A Comparative Evaluation on Antimicrobial Effect of Honey, Neem Leaf Extract and Sodium Hypochlorite as Intracanal Irrigant: An Ex-Vivo Study

PubMed Central

Narayanan, Retna Kumari; Vadakkepurayil, Kannan

2016-01-01

Introduction The major determinant of the success of root canal treatment depends on meticulous disinfection of the root canal using intracanal irrigants. The most commonly used root canal irrigant is sodium hypochlorite which has disadvantages of cytotoxicity and unpleasant taste. So there is a need to identify a more biocompatible root canal irrigant. Aim The aim of this ex-vivo study was to evaluate the efficacy of 40% honey, 100% neem leaf extract and 5.25% sodium hypochlorite as an intracanal irrigant against the isolated microorganisms from infected root canal. Materials and Methods The samples were collected from infected root canals of 60 primary molar teeth indicated for pulpectomy. Alpha hemolytic Streptococci, gram negative bacilli, Candida, Staphylococci, Lactobacilli, Enterococci, Spore bearing gram positive bacilli and Micrococci were the microorganisms isolated from the samples. The zone of inhibition against the microbial growth was measured by agar well diffusion method. Statistical analysis was done by Repeated Analysis of Variance (ANOVA) and Bonferroni method. Results Statistical analysis showed that the means of the zones of inhibition measured in this study were 18.56mm, 2.09mm and 1.62mm for sodium hypochlorite, 100% neem leaf extract and 40% honey respectively. The significance was greater between sodium hypochlorite and the other two agents as p-value was <0.001. Conclusion The results indicated that 5.25% sodium hypochlorite is more effective as root canal irrigant when compared with 100% neem leaf extract and 40% honey. It was also observed that 100% neem leaf extract has greater antimicrobial effect than 40% honey. PMID:27656571

Soil degradation in farmlands of California's San Joaquin Valley resulting from drought-induced land-use changes

NASA Astrophysics Data System (ADS)

Scudiero, Elia; Skaggs, Todd; Anderson, Ray; Corwin, Dennis

2016-04-01

Irrigation in California's Central Valley (USA) has decreased significantly due to water shortages resulting from the current drought, which began in 2010. In particular, fallow fields in the west side of the San Joaquin Valley (WSJV), which is the southwest portion of the Central Valley, increased from around 12% in the years before the drought (2007-2010) to 20-25% in the following years (2011-2015). We monitored and mapped drought-induced edaphic changes in salinity at two scales: (i) field scale (32.4-ha field in Kings County) and (ii) water district scale (2400 ha at -former- Broadview Water District in Fresno County). At both scales drought-induced land-use changes (i.e., shift from irrigated agriculture to fallow) drastically decreased soil quality by increasing salinity (and sodicity), especially in the root-zone (top 1.2 m). The field study monitors the spatial (three dimensions) changes of soil salinity (and sodicity) in the root-zone during 10 years of irrigation with drainage water followed by 4 years of no applied irrigation water (only rainfall) due to drought conditions. Changes of salinity (and other edaphic properties), through the soil profile (down to 1.2 m, at 0.3-m increments), were monitored and modeled using geospatial apparent electrical conductivity measurements and extensive soil sampling in 1999, 2002, 2004, 2009, 2011, and 2013. Results indicate that when irrigation was applied, salts were leached from the root-zone causing a remarkable improvement in soil quality. However, in less than two years after termination of irrigation, salinity in the soil profile returned to original levels or higher across the field. At larger spatial scales the effect of drought-induced land-use change on root-zone salinity is also evident. Up to spring 2006, lands in Broadview Water District (BWD) were used for irrigated agriculture. Water rights were then sold and the farmland was retired. Soil quality decreased since land retirement, especially during the drought years. Root-zone soil salinity was mapped in 1991 using geospatial apparent electrical conductivity measurements and extensive soil sampling and in 2013 using recent root-zone remote sensing salinity map for the WSJV (developed and published by the U.S. Salinity Laboratory, USDA-ARS), which was calibrated and (independently) validated, including fields from the BWD. Results reveal dramatic increases in soil salinity for all the fields that were originally non-saline and slightly-saline in 1991. Additionally, time-series analysis of very-high resolution ortho-imagery (from Google Earth and USGS) suggests that surface soil quality drastically decreased especially during the drought years. Our research shows how terminating irrigation in California's Central Valley can lead to substantial soil salinization in a very short time. Salinization in WSJV due to the termination of irrigation is a consequence of the complex multi-scale interaction of geomorphologic, topographic, and anthropogenic factors requiring yearly monitoring to adequately assess the impacts of drought for use in field- and basin-scale water management decisions. Among other concerns, increased salinity and sodicity affect vegetation growth and may lead to increased soil erosion and very-fine dust formation creating health and environmental hazards.

Interactive Effects of Elevated CO2 and N Fertilization on Yield and Quality of Tomato Grown Under Reduced Irrigation Regimes

PubMed Central

Wei, Zhenhua; Du, Taisheng; Li, Xiangnan; Fang, Liang; Liu, Fulai

2018-01-01

The interactive effects of CO2 elevation, N fertilization, and reduced irrigation regimes on fruit yield (FY) and quality in tomato (Solanum lycopersicum L.) were investigated in a split-root pot experiment. The plants were grown in two separate climate-controlled greenhouse cells at atmospheric [CO2] of 400 and 800 ppm, respectively. In each cell, the plants were fertilized at either 100 or 200 mg N kg-1 soil and were either irrigated to full water holding capacity [i.e., a volumetric soil water content of 18%; full irrigation (FI)], or using 70% water of FI to the whole pot [deficit irrigation (DI)] or alternately to only half of the pot [partial root-zone irrigation (PRI)]. The yield and fruit quality attributes mainly from sugars (sucrose, fructose, and glucose) and organic acids (OAs; citric acid and malic acid) to various ionic (NH4+, K+, Mg2+, Ca2+, NO3-, SO42-, and PO43-) concentrations in fruit juice were determined. The results indicated that lower N supply reduced fruit number and yield, whereas it enhanced some of the quality attributes of fruit as indicated by greater firmness and higher concentrations of sugars and OAs. Elevated [CO2] (e[CO2]) attenuated the negative influence of reduced irrigation (DI and PRI) on FY. Principal component analysis revealed that the reduced irrigation regimes, especially PRI, in combination with e[CO2] could synergistically improve the comprehensive quality of tomato fruits at high N supply. These findings provide useful knowledge for sustaining tomato FY and quality in a future drier and CO2-enriched environment. PMID:29636756

Influences of the unsaturated, saturated, and riparian zones on the transport of nitrate near the Merced River, California, USA

USGS Publications Warehouse

Domagalski, Joseph L.; Phillips, S.P.; Bayless, E.R.; Zamora, C.; Kendall, C.; Wildman, R.A.; Hering, J.G.

2008-01-01

Transport and transformation of nitrate was evaluated along a 1-km groundwater transect from an almond orchard to the Merced River, California, USA, within an irrigated agricultural setting. As indicated by measurements of pore-water nitrate and modeling using the root zone water quality model, about 63% of the applied nitrogen was transported through a 6.5-m unsaturated zone. Transport times from recharge locations to the edge of a riparian zone ranged from approximately 6 months to greater than 100 years. This allowed for partial denitrification in horizons having mildly reducing conditions, and essentially no denitrification in horizons with oxidizing conditions. Transport times across a 50-100-m-wide riparian zone of less than a year to over 6 years and more strongly reducing conditions resulted in greater rates of denitrification. Isotopic measurements and concentrations of excess N2 in water were indicative of denitrification with the highest rates below the Merced River. Discharge of water and nitrate into the river was dependent on gradients driven by irrigation or river stage. The results suggest that the assimilative capacity for nitrate of the groundwater system, and particularly the riverbed, is limiting the nitrate load to the Merced River in the study area. ?? Springer-Verlag 2007.

Optimizing ET-based irrigation scheduling for wheat and maize with water constraints

USDA-ARS?s Scientific Manuscript database

Deficit irrigation is proved to increase crop water use efficiency (WUE) in water limited areas, but effective irrigation required better understanding of crop responses to water stress intensity and timing. In this study, the Root Zone Water Quality Model (RZWQM) was first calibrated and validated ...

Root Zone Sensors for Irrigation Management in Intensive Agriculture

PubMed Central

Pardossi, Alberto; Incrocci, Luca; Incrocci, Giorgio; Malorgio, Fernando; Battista, Piero; Bacci, Laura; Rapi, Bernardo; Marzialetti, Paolo; Hemming, Jochen; Balendonck, Jos

2009-01-01

Crop irrigation uses more than 70% of the world’s water, and thus, improving irrigation efficiency is decisive to sustain the food demand from a fast-growing world population. This objective may be accomplished by cultivating more water-efficient crop species and/or through the application of efficient irrigation systems, which includes the implementation of a suitable method for precise scheduling. At the farm level, irrigation is generally scheduled based on the grower’s experience or on the determination of soil water balance (weather-based method). An alternative approach entails the measurement of soil water status. Expensive and sophisticated root zone sensors (RZS), such as neutron probes, are available for the use of soil and plant scientists, while cheap and practical devices are needed for irrigation management in commercial crops. The paper illustrates the main features of RZS’ (for both soil moisture and salinity) marketed for the irrigation industry and discusses how such sensors may be integrated in a wireless network for computer-controlled irrigation and used for innovative irrigation strategies, such as deficit or dual-water irrigation. The paper also consider the main results of recent or current research works conducted by the authors in Tuscany (Italy) on the irrigation management of container-grown ornamental plants, which is an important agricultural sector in Italy. PMID:22574047

Accounting for sap flow from different parts of the root system improves the prediction of xylem ABA concentration in plants grown with heterogeneous soil moisture.

PubMed

Dodd, Ian C; Egea, Gregorio; Davies, William J

2008-01-01

When soil moisture is heterogeneous, sap flow from, and ABA status of, different parts of the root system impact on leaf xylem ABA concentration ([X-ABA]leaf). The robustness of a model for predicting [X-ABA]leaf was assessed. 'Two root-one shoot' grafted sunflower (Helianthus annuus L.) plants received either deficit irrigation (DI, each root system received the same irrigation volumes) or partial rootzone drying (PRD, only one root system was watered and the other dried the soil). Irrespective of whether relative sap flow was assessed using sap flow sensors in vivo or by pressurization of de-topped roots, each root system contributed similarly to total sap flow during DI, while sap flow from roots in drying soil declined linearly with soil water potential (Psisoil) during PRD. Although Psisoil of the irrigated pot determined the threshold Psisoil at which sap flow from roots in drying soil decreased, the slope of this decrease was independent of the wet pot Psisoil. Irrespective of whether sap was collected from the wet or dry root system of PRD plants, or a DI plant, root xylem ABA concentration increased as Psisoil declined. The model, which weighted ABA contributions of each root system according to the sap flow from each, almost perfectly explained [X-ABA] immediately above the graft union. That the model overestimated measured [X-ABA]leaf may result from changes in [X-ABA] along the transport pathway or an artefact of collecting xylem sap from detached leaves. The implications of declining sap flow through partially dry roots during PRD for the control of stomatal behaviour and irrigation scheduling are discussed.

Nebraska's groundwater legacy: Nitrate contamination beneath irrigated cropland

PubMed Central

Exner, Mary E; Hirsh, Aaron J; Spalding, Roy F

2014-01-01

A 31 year record of ∼44,000 nitrate analyses in ∼11,500 irrigation wells was utilized to depict the decadal expansion of groundwater nitrate contamination (N ≥ 10 mg/L) in the irrigated corn-growing areas of eastern and central Nebraska and analyze long-term nitrate concentration trends in 17 management areas (MAs) subject to N fertilizer and budgeting requirements. The 1.3 M contaminated hectares were characterized by irrigation method, soil drainage, and vadose zone thickness and lithology. The areal extent and growth of contaminated groundwater in two predominately sprinkler-irrigated areas was only ∼20% smaller beneath well-drained silt loams with thick clayey-silt unsaturated layers and unsaturated thicknesses >15 m (400,000 ha and 15,000 ha/yr) than beneath well and excessively well-drained soils with very sandy vadose zones (511,000 ha and 18,600 ha/yr). Much slower expansion (3700 ha/yr) occurred in the 220,000 contaminated hectares in the central Platte valley characterized by predominately gravity irrigation on thick, well-drained silt loams above a thin (∼5.3 m), sandy unsaturated zone. The only reversals in long-term concentration trends occurred in two MAs (120,500 ha) within this contaminated area. Concentrations declined 0.14 and 0.20 mg N/L/yr (p < 0.02) to ∼18.3 and 18.8 mg N/L, respectively, during >20 years of management. Average annual concentrations in 10 MAs are increasing (p < 0.05) and indicate that average nitrate concentrations in leachates below the root zone and groundwater concentrations have not yet reached steady state. While management practices likely have slowed increases in groundwater nitrate concentrations, irrigation and nutrient applications must be more effectively controlled to retain nitrate in the root zone. PMID:25558112

Quantifying long-term responses of crop yield and nitrate leaching in an intensive farmland using agro-eco-environmental model.

PubMed

Sun, Mei; Huo, Zailin; Zheng, Yanxia; Dai, Xiaoqin; Feng, Shaoyuan; Mao, Xiaomin

2018-02-01

Quantitatively ascertaining and analyzing long-term responses of crop yield and nitrate leaching on varying irrigation and fertilization treatments are focal points for guaranteeing crop yield and reducing nitrogen loss. The calibrated agricultural-hydrological RZWQM2 model was used to explore the long-term (2003-2013) transport processes of water and nitrogen and the nitrate leaching amount into groundwater in summer maize and winter wheat rotation field in typical intensive plant area in the North China Plain, Daxing district of Beijing. Simulation results showed that application rates of irrigation and nitrogen fertilizer have couple effects on crop yields and nitrogen leaching of root zone. When both the irrigation and fertilizer for summer maize and winter wheat were 400mm and 400kgNha -1 , respectively, nitrate leaching into groundwater accounted for 47.9% of application amount of nitrogen fertilizer. When application amount of irrigation is 200mm and fertilization is 200kgNha -1 , NUPE (nitrogen uptake efficiency), NUE (nitrogen use efficiency), NPFP (nitrogen partial factor productivity), and W pi (irrigation water productive efficiency) were in general higher than that under other irrigation and fertilization condition (irrigation from 104-400mm, fertilizer 104-400kgNha -1 ). Irrigation bigger than 200mm could shorten the response time of nitrate leaching in deeper soil layer in different irrigation treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

Time-lapse 3D electrical resistivity tomography to monitor soil-plant interactions

NASA Astrophysics Data System (ADS)

Boaga, Jacopo; Rossi, Matteo; Cassiani, Giorgio; Putti, Mario

2013-04-01

In this work we present the application of time-lapse non-invasive 3D micro- electrical tomography (ERT) to monitor soil-plant interactions in the root zone in the framework of the FP7 Project CLIMB (Climate Induced Changes on the Hydrology of Mediterranean Basins). The goal of the study is to gain a better understanding of the soil-vegetation interactions by the use of non-invasive techniques. We designed, built and installed a 3D electrical tomography apparatus for the monitoring of the root zone of a single apple tree in an orchard located in the Trentino region, Northern Italy. The micro-ERT apparatus consists of 48 buried electrodes on 4 instrumented micro boreholes plus 24 mini-electrodes on the surface spaced 0.1 m on a square grid. We collected repeated ERT and TDR soil moisture measurements for one year and performed two different controlled irrigation tests: one during a very dry Summer and one during a very wet and highly dynamic plant growing Spring period. We also ran laboratory analyses on soil specimens, in order to evaluate the electrical response at different saturation steps. The results demonstrate that 3D micro-ERT is capable of characterizing subsoil conditions and monitoring root zone activities, especially in terms of root zone suction regions. In particular, we note that in very dry conditions, 3D micro ERT can image water plumes in the shallow subsoil produced by a drip irrigation system. In the very dynamic growing season, under abundant irrigation, micro 3D ERT can detect the main suction zones caused by the tree root activity. Even though the quantitative use of this technique for moisture content balance suffers from well-known inversion difficulties, even the pure imaging of the active root zone is a valuable contribution. However the integration of the measurements in a fully coupled hydrogeophysical inversion is the way forward for a better understanding of subsoil interactions between biomass, hydrosphere and atmosphere.

Model development for prediction of soil water dynamics in plant production.

PubMed

Hu, Zhengfeng; Jin, Huixia; Zhang, Kefeng

2015-09-01

Optimizing water use in agriculture and medicinal plants is crucially important worldwide. Soil sensor-controlled irrigation systems are increasingly becoming available. However it is questionable whether irrigation scheduling based on soil measurements in the top soil could make best use of water for deep-rooted crops. In this study a mechanistic model was employed to investigate water extraction by a deep-rooted cabbage crop from the soil profile throughout crop growth. The model accounts all key processes governing water dynamics in the soil-plant-atmosphere system. Results show that the subsoil provides a significant proportion of the seasonal transpiration, about a third of water transpired over the whole growing season. This suggests that soil water in the entire root zone should be taken into consideration in irrigation scheduling, and for sensor-controlled irrigation systems sensors in the subsoil are essential for detecting soil water status for deep-rooted crops.

Vegetative growth and cluster development in Shiraz grapevines subjected to partial root-zone cooling

PubMed Central

Rogiers, Suzy Y.; Clarke, Simon J.

2013-01-01

Heterogeneity in root-zone temperature both vertically and horizontally may contribute to the uneven vegetative and reproductive growth often observed across vineyards. An experiment was designed to assess whether the warmed half of a grapevine root zone could compensate for the cooled half in terms of vegetative growth and reproductive development. We divided the root system of potted Shiraz grapevines bilaterally and applied either a cool or a warm treatment to each half from budburst to fruit set. Shoot growth and inflorescence development were monitored over the season. Simultaneous cooling and warming of parts of the root system decreased shoot elongation, leaf emergence and leaf expansion below that of plants with a fully warmed root zone, but not to the same extent as those with a fully cooled root zone. Inflorescence rachis length, flower number and berry number after fertilization were smaller only in those vines exposed to fully cooled root zones. After terminating the treatments, berry enlargement and the onset of veraison were slowed in those vines that had been exposed to complete or partial root-zone cooling. Grapevines exposed to partial root-zone cooling were thus delayed in vegetative and reproductive development, but the inhibition was greater in those plants whose entire root system had been cooled. PMID:24244839

A root zone modelling approach to estimating groundwater recharge from irrigated areas

NASA Astrophysics Data System (ADS)

Jiménez-Martínez, J.; Skaggs, T. H.; van Genuchten, M. Th.; Candela, L.

2009-03-01

SummaryIn irrigated semi-arid and arid regions, accurate knowledge of groundwater recharge is important for the sustainable management of scarce water resources. The Campo de Cartagena area of southeast Spain is a semi-arid region where irrigation return flow accounts for a substantial portion of recharge. In this study we estimated irrigation return flow using a root zone modelling approach in which irrigation, evapotranspiration, and soil moisture dynamics for specific crops and irrigation regimes were simulated with the HYDRUS-1D software package. The model was calibrated using field data collected in an experimental plot. Good agreement was achieved between the HYDRUS-1D simulations and field measurements made under melon and lettuce crops. The simulations indicated that water use by the crops was below potential levels despite regular irrigation. The fraction of applied water (irrigation plus precipitation) going to recharge ranged from 22% for a summer melon crop to 68% for a fall lettuce crop. In total, we estimate that irrigation of annual fruits and vegetables produces 26 hm 3 y -1 of groundwater recharge to the top unconfined aquifer. This estimate does not include important irrigated perennial crops in the region, such as artichoke and citrus. Overall, the results suggest a greater amount of irrigation return flow in the Campo de Cartagena region than was previously estimated.

On the Control of Solute Mass Fluxes and Concentrations Below Fields Irrigated With Low-Quality Water: A Numerical Study

NASA Astrophysics Data System (ADS)

Russo, David

2017-11-01

The main goal of this study was to test the capability of irrigation water-based and soil-based approaches to control nitrate and chloride mass fluxes and concentrations below the root zone of agricultural fields irrigated with treated waste water (TWW). Using numerical simulations of flow and transport in relatively a fine-textured, unsaturated, spatially heterogeneous, flow domain, scenarios examined include: (i) irrigating with TWW only (REF); (ii) irrigation water is substituted between TWW and desalinized water (ADW); (iii) soil includes a capillary barrier (CB) and irrigating with TWW only (CB + TWW); and (iv) combination of (ii) and a CB (CB + ADW). Considering groundwater quality protection, plausible goals are: (i) to minimize solute discharges leaving the root zone, and, (ii) to maximize the probability that solute concentrations leaving the root zone will not exceed a prescribed, critical value. Results of the analyses suggest that in the case of a seasonal crop (a corn field) subject to irrigations only, with respect to the first goal, the CB + TWW and CB + ADW scenarios provide similar, excellent results, better than the ADW scenario; with respect to the second goal, however, the CB + ADW scenario gave substantially better results than the CB + TWW scenario. In the case a multiyear, perennial crop (a citrus orchard), subject to a sequence of irrigation and rainfall periods, for both solutes, and, particularly, nitrate, with respect to the two goals, both the ADW and CB + ADW scenarios perform better than the CB + TWW scenario. As compared with the REF and CB + TWW scenarios, the ADW and CB + ADW scenarios substantially reduce nitrogen mass fluxes to the groundwater and to the atmosphere, and, essentially, did not reduce nitrogen mass fluxes to the trees. Similar results, even better, were demonstrated for a relatively coarse-textured, spatially heterogeneous soil.

A comprehensive guide for designing more efficient irrigation systems with respect to application control

NASA Astrophysics Data System (ADS)

Khaddam, Issam; Schuetze, Niels

2017-04-01

The worldwide water scarcity problems are expected to aggravate due to the increasing population and the need to produce more food. Irrigated agriculture is considered the highest consumer of fresh water resources with a rate exceeds 70% of global consumption. Consequently, an improvement in the efficiency of all irrigation methods, such as furrow or drip irrigation, becomes more necessary and urgent. Therefore, a more precise knowledge about soil water distribution in the root zone and the water balance components is required. For this purpose and as a part of the SAPHIR project (Saxonian Platform for high Performance Irrigation), a 2D simulation- based study was performed with virtual field conditions. The study investigates the most important design parameters of many irrigation systems, such as irrigation intensity and duration, and shows there influence on the water distribution efficiency. Furthermore, three main soil textures are used to test the impact of the soil hydraulic properties on irrigation effectiveness. A numerous number of irrigation scenarios of each irrigation system was simulated using HYDRUS 2D. Thereafter, the results were digitally calculated, compiled and made available online in the so called "Irrigation Atlases". The irrigation atlases provide graphical results of the soil moisture and pressure head distributions in the root zone. Moreover, they contain detailed information of the water balance for all simulated scenarios. The most studies evaluate the irrigation water demands on local, regional or global scales and for that an efficient water distribution is required. In this context, the irrigation atlases can serve as a valuable tool for the implementation of planned irrigation measures.

Vitality of Enterococcus faecalis inside dentinal tubules after five root canal disinfection methods

PubMed Central

Vatkar, Niranjan Ashok; Hegde, Vivek; Sathe, Sucheta

2016-01-01

Aim: To compare the vitality of Enterococcus faecalis within dentinal tubules after subjected to five root canal disinfection methods. Materials and Methods: Dentin blocks (n = 60) were colonized with E. faecalis. After 4 weeks of incubation, the dentin blocks were divided into one control and five test groups (n = 10 each). The root canals of test groups were subjected to one of the disinfection methods, namely, normal saline (NS), sodium hypochlorite (NaOCl), chlorhexidine digluconate (CHX), neodymium-doped yttrium aluminum garnet (Nd: YAG) laser, and diode laser. The effect of disinfection methods was assessed by LIVE/DEAD BacLight stain under the confocal laser scanning microscopy to determine the “zone of dead bacteria” (ZDB). Mean values were calculated for ZDB and the difference between groups was established. Results: Penetration of E. faecalis was seen to a depth of >1000 μm. Viable bacteria were detected with NS irrigation. NaOCl and CHX showed partial ZDB. When the root canals were disinfected with Nd: YAG and diode lasers, no viable bacteria were found. Conclusion: E. faecalis has the ability to colonize inside dentinal tubules to a depth of >1000 μm. In contrast to conventional irrigants, both Nd: YAG and diode lasers were effective in eliminating the vitality of E. faecalis. NS, NaOCl, and CHX showed viable bacteria remaining in dentinal tubules. PMID:27656064

Developing an automated water emitting-sensing system, based on integral tensiometers placed in homogenous environment.

NASA Astrophysics Data System (ADS)

Dabach, Sharon; Shani, Uri

2010-05-01

As the population grows, irrigated agriculture is using more water and fertilizers to supply the growing food demand. However, the uptake by various plants is only 30 to 50% of the water applied. The remaining water flows to surface water and groundwater and causes their contamination by fertilizers or other toxins such as herbicides or pesticides. To improve the water use efficiency of crops and decrease the drainage below the root zone, irrigation water should be applied according to the plant demand. The aim of this work is to develop an automated irrigation system based on real-time feedback from an inexpensive and reliable integrated sensing system. This system will supply water to plants according to their demand, without any user interference during the entire growth season. To achieve this goal a sensor (Geo-Tensiometer) was designed and tested. This sensor has better contact with the surrounding soil, is more reliable and much cheaper than the ceramic cup tensiometer. A lysimeter experiment was conducted to evaluate a subsurface drip irrigation regime based on the Geo-Tensiometer and compare it to a daily irrigation regime. All of the drippers were wrapped in Geo-textile. By integrating the Geo-Tensiometer within the Geo-textile which surrounds the drippers, we created a homogenous media in the entire lysimeter in which the reading of the matric potential takes place. This media, the properties of which are set and known to us, encourages root growth therein. Root density in this media is very high; therefore most of the plant water uptake is from this area. The irrigation system in treatment A irrigated when the matric potential reached a threshold which was set every morning automatically by the system. The daily treatment included a single irrigation each morning that was set to return 120% of the evapotranspiration of the previous day. All Geo-Tensiometers were connected to an automated washing system, that flushed air trapped in the Geo-Tensiometers. In treatment A, the system discharge changed according to the plant water demand. The discharge changes followed the water uptake changes during the day and during the entire growth period without any user interference. The integration of Geo-Tensiometer into the emitter system, together with the irrigation regime, maintained high and constant water content in the root zone in comparison to other irrigation methods, such as daily drip irrigation. Reading the matric potential in this media yielded better indication of water availability to the plants than sensors placed 3 cm from the emitters. In addition, the amount of water drainage below the root zone decreased significantly and therefore the threat of polluting groundwater. Furthermore, the automated flushing system eliminated the need for manual maintenance of the tensiometers creating a user friendly system.

Modelling and Evaluation of Non-Linear Rootwater Uptake for Winter Cropping of Wheat and Berseem

NASA Astrophysics Data System (ADS)

GS, K.; Prasad, K. S. H.

2017-12-01

The plant water uptake is significant for study to monitor the irrigation supplied to the plant. The Richards equation has been the key governing equation to quantify the root water uptake in the vadose zone and it takes all the sources and sink terms into consideration. The β parameter or the non linearity parameter is used in this modeling to bring the non linearity in the plant root water uptake. The soil parameters are obtained by experimentation and are employed in the Van-Genuchten equation for soil moisture study. Field experiments were carried out at Civil Engineering Department IIT Roorkee, Uttarakhand, India, during the winter season of 2013 and 2014 for berseem and 2016 for wheat as per the local cropping practices. Drainage type lysimeters were installed to study the soil water balance. Soil moisture was monitored using profile probe. Precipitation and all meteorological data were obtained from the nearby gauges located at the National Institute of Hydrology, Roorkee.The moisture data and the deep percolation data were collected on a daily basis and the irrigation supply was controlled and monitored to satisfy the moisture requirements of the crops respectively.In order to study the effect of water scarcity on the crops, the plot was divided and deficited irrigation was applied for the second cropping season for Berseem.The yields for both the seasons was also measured. The solution of Richards equation as applied to the moisture movement in the root zone was modeled. For estimation of root water uptake, the governing equation is the one-dimensional mixed form of Richards' equation is employed (Ji et al., 2007; Shankar et al., 2012).The sink term in the model accounts for the root water uptake, which is utilized by the plant for transpiration. Smaxor the maximum root water uptake for the root zone on a given day must be equal to the maximum transpiration on the corresponding day The model computed moisture content and pressure head is calibrated with the measured soil water content in the crop root zone. The Model output is compared with the output of the HYDRUS 1D software package. The complete calibrated model is now employed to determine the irrigation requirement of crops for a known initial moisture content and available precipitation and can be useful for economical agriculture in the semi-arid regions of India.

Growth and proteomic analysis of tomato fruit under partial root-zone drying.

PubMed

Marjanović, Milena; Stikić, Radmila; Vucelić-Radović, Biljana; Savić, Sladjana; Jovanović, Zorica; Bertin, Nadia; Faurobert, Mireille

2012-06-01

The effects of partial root-zone drying (PRD) on tomato fruit growth and proteome in the pericarp of cultivar Ailsa Craig were investigated. The PRD treatment was 70% of water applied to fully irrigated (FI) plants. PRD reduced the fruit number and slightly increased the fruit diameter, whereas the total fruit fresh weight (FW) and dry weight (DW) per plant did not change. Although the growth rate was higher in FI than in PRD fruits, the longer period of cell expansion resulted in bigger PRD fruits. Proteins were extracted from pericarp tissue at two fruit growth stages (15 and 30 days post-anthesis [dpa]), and submitted to proteomic analysis including two-dimensional gel electrophoresis and mass spectrometry for identification. Proteins related to carbon and amino acid metabolism indicated that slower metabolic flux in PRD fruits may be the cause of a slower growth rate compared to FI fruits. The increase in expression of the proteins related to cell wall, energy, and stress defense could allow PRD fruits to increase the duration of fruit growth compared to FI fruits. Upregulation of some of the antioxidative enzymes during the cell expansion phase of PRD fruits appears to be related to their role in protecting fruits against the mild stress induced by PRD.

Soil nitrogen balance under wastewater management: Field measurements and simulation results

USGS Publications Warehouse

Sophocleous, M.; Townsend, M.A.; Vocasek, F.; Ma, Liwang; KC, A.

2009-01-01

The use of treated wastewater for irrigation of crops could result in high nitrate-nitrogen (NO3-N) concentrations in the vadose zone and ground water. The goal of this 2-yr field-monitoring study in the deep silty clay loam soils south of Dodge City, Kansas, was to assess how and under what circumstances N from the secondary-treated, wastewater-irrigated corn reached the deep (20-45 m) water table of the underlying High Plains aquifer and what could be done to minimize this problem. We collected 15.2-m-deep soil cores for characterization of physical and chemical properties; installed neutron probe access tubes to measure soil-water content and suction lysimeters to sample soil water periodically; sampled monitoring, irrigation, and domestic wells in the area; and obtained climatic, crop, irrigation, and N application rate records for two wastewater-irrigated study sites. These data and additional information were used to run the Root Zone Water Quality Model to identify key parameters and processes that influence N losses in the study area. We demonstrated that NO3-N transport processes result in significant accumulations of N in the vadose zone and that NO3-N in the underlying ground water is increasing with time. Root Zone Water Quality Model simulations for two wastewater-irrigated study sites indicated that reducing levels of corn N fertilization by more than half to 170 kg ha-1 substantially increases N-use efficiency and achieves near-maximum crop yield. Combining such measures with a crop rotation that includes alfalfa should further reduce the accumulation and downward movement of NO3-N in the soil profile. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

Effects of different irrigation practices using treated wastewater on tomato yields, quality, water productivity, and soil and fruit mineral contents.

PubMed

Demir, Azize Dogan; Sahin, Ustun

2017-11-01

Wastewater use in agricultural irrigation is becoming a common practice in order to meet the rising water demands in arid and semi-arid regions. The study was conducted to determine the effects of the full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation practices using treated municipal wastewater (TWW) and freshwater (FW) on tomato yield, water use, fruit quality, and soil and fruit heavy metal concentrations. The TWW significantly increased marketable yield compared to the FW, as well as decreased water consumption. Therefore, water use efficiency (WUE) in the TWW was significantly higher than in the FW. Although the DI and the PRD practices caused less yields, these practices significantly increased WUE values due to less irrigation water applied. The water-yield linear relationships were statistically significant. TWW significantly increased titratable acidity and vitamin C contents. Reduced irrigation provided significantly lower titratable acidity, vitamin C, and lycopene contents. TWW increased the surface soil and fruit mineral contents in response to FW. Greater increases were observed under FI, and mineral contents declined with reduction in irrigation water. Heavy metal accumulation in soils was within safe limits. However, Cd and Pb contents in fruits exceeded standard limits given by FAO/WHO. Higher metal pollution index values determined for fruits also indicated that TWW application, especially under FI, might cause health risks in long term.

Analytical steady-state solutions for water-limited cropping systems using saline irrigation water

NASA Astrophysics Data System (ADS)

Skaggs, T. H.; Anderson, R. G.; Corwin, D. L.; Suarez, D. L.

2014-12-01

Due to the diminishing availability of good quality water for irrigation, it is increasingly important that irrigation and salinity management tools be able to target submaximal crop yields and support the use of marginal quality waters. In this work, we present a steady-state irrigated systems modeling framework that accounts for reduced plant water uptake due to root zone salinity. Two explicit, closed-form analytical solutions for the root zone solute concentration profile are obtained, corresponding to two alternative functional forms of the uptake reduction function. The solutions express a general relationship between irrigation water salinity, irrigation rate, crop salt tolerance, crop transpiration, and (using standard approximations) crop yield. Example applications are illustrated, including the calculation of irrigation requirements for obtaining targeted submaximal yields, and the generation of crop-water production functions for varying irrigation waters, irrigation rates, and crops. Model predictions are shown to be mostly consistent with existing models and available experimental data. Yet the new solutions possess advantages over available alternatives, including: (i) the solutions were derived from a complete physical-mathematical description of the system, rather than based on an ad hoc formulation; (ii) the analytical solutions are explicit and can be evaluated without iterative techniques; (iii) the solutions permit consideration of two common functional forms of salinity induced reductions in crop water uptake, rather than being tied to one particular representation; and (iv) the utilized modeling framework is compatible with leading transient-state numerical models.

Discrimination of plant root zone water status in greenhouse production based on phenotyping and machine learning techniques.

PubMed

Guo, Doudou; Juan, Jiaxiang; Chang, Liying; Zhang, Jingjin; Huang, Danfeng

2017-08-15

Plant-based sensing on water stress can provide sensitive and direct reference for precision irrigation system in greenhouse. However, plant information acquisition, interpretation, and systematical application remain insufficient. This study developed a discrimination method for plant root zone water status in greenhouse by integrating phenotyping and machine learning techniques. Pakchoi plants were used and treated by three root zone moisture levels, 40%, 60%, and 80% relative water content. Three classification models, Random Forest (RF), Neural Network (NN), and Support Vector Machine (SVM) were developed and validated in different scenarios with overall accuracy over 90% for all. SVM model had the highest value, but it required the longest training time. All models had accuracy over 85% in all scenarios, and more stable performance was observed in RF model. Simplified SVM model developed by the top five most contributing traits had the largest accuracy reduction as 29.5%, while simplified RF and NN model still maintained approximately 80%. For real case application, factors such as operation cost, precision requirement, and system reaction time should be synthetically considered in model selection. Our work shows it is promising to discriminate plant root zone water status by implementing phenotyping and machine learning techniques for precision irrigation management.

Soil Water Sensing-Focus on Variable Rate Irrigation

USDA-ARS?s Scientific Manuscript database

Irrigation scheduling using soil water sensors is an exercise in maintaining the water content of the crop root zone soil above a lower limit defined by the management allowed depletion (MAD) for that soil and crop, but not so wet that too much water is lost to deep percolation. The management allow...

76 FR 50171 - Notice of Intent To Prepare an Environmental Impact Statement for the Henrys Fork Salinity...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-12

... following methods: Government-wide rulemaking Web site: http://www.regulations.gov . Follow the instructions... irrigation system improvements outlined in this plan will provide more efficient use of this water. Deep... reduction of excess deep percolation passing below the plant root zone. Deep percolation of irrigation water...

Nitrogen fluxes through unsaturated zones in five agricultural settings across the USA

NASA Astrophysics Data System (ADS)

Green, C. T.; Fisher, L. H.; Bekins, B. A.

2006-12-01

The main controls on nitrogen (N) fluxes between the root zone and the water table were determined for agricultural sites in California, Washington, Nebraska, Indiana, and Maryland in 2004 and 2005. Sites included irrigated and non-irrigated fields; soil textures ranging from clay to sand; crops including corn, soybeans, almonds, and pasture; and unsaturated zone thicknesses ranging from 0.5 to 20 m. Chemical analyses of water from lysimeters, shallow wells, and sediment cores indicate that advective transport of nitrate is the dominant process affecting the rate of N transport below the root zone. Vertical profiles of (1) N species, (2) stable N and O isotopes, and (3) oxygen gas in unsaturated zone air and shallow ground water, and correlations between N and other agricultural chemicals indicate that reactions do not greatly affect N concentrations between the root zone and the capillary fringe. Relatively stable concentrations at depths greater than a few meters allow calculation of nitrogen fluxes to the saturated zone. These fluxes are equivalent to 14 - 64% of the N application rates. At the same locations, median vertical fluxes of N in ground water are generally lower, ranging from 4 - 37% of N application rates. The lower nitrate fluxes in ground water reflect processes including lateral flow to tile drains and denitrification in the capillary fringe, as well as historical changes in N inputs.

Effect of Post-Infiltration Soil Aeration at Different Growth Stages on Growth and Fruit Quality of Drip-Irrigated Potted Tomato Plants (Solanum lycopersicum)

PubMed Central

Li, Yuan; Jia, Zongxia; Niu, Wenquan; Wang, Jingwei; Zhang, Mingzhi

2015-01-01

Soil hydraulic principles suggest that post-infiltration hypoxic conditions would be induced in the plant root-zone for drip-irrigated tomato production in small pots filled with natural soil. No previous study specifically examined the response of tomato plants (Solanum lycopersicum) at different growth stages to low soil aeration under these conditions. A 2 × 6 factorial experiment was conducted to quantify effects of no post-infiltration soil aeration versus aeration during 5 different periods (namely 27–33, 34–57, 58–85, 86–99, and 27–99 days after sowing), on growth and fruit quality of potted single tomato plants that were sub-surface trickle-irrigated every 2 days at 2 levels. Soil was aerated by injecting 2.5 liters of air into each pot through the drip tubing immediately after irrigation. Results showed that post-infiltration aeration, especially during the fruit setting (34–57 DAS) and enlargement (58–85 DAS) growth stages, can positively influence the yield, root dry weight and activity, and the nutritional (soluble solids and vitamin C content), taste (titratable acidity), and market quality (shape and firmness) of the tomato fruits. Interactions between irrigation level and post-infiltration aeration on some of these fruit quality parameters indicated a need for further study on the dynamic interplay of air and water in the root zone of the plants under the conditions of this experiment. PMID:26630675

Effect of Post-Infiltration Soil Aeration at Different Growth Stages on Growth and Fruit Quality of Drip-Irrigated Potted Tomato Plants (Solanum lycopersicum).

PubMed

Li, Yuan; Jia, Zongxia; Niu, Wenquan; Wang, Jingwei; Zhang, Mingzhi

2015-01-01

Soil hydraulic principles suggest that post-infiltration hypoxic conditions would be induced in the plant root-zone for drip-irrigated tomato production in small pots filled with natural soil. No previous study specifically examined the response of tomato plants (Solanum lycopersicum) at different growth stages to low soil aeration under these conditions. A 2 × 6 factorial experiment was conducted to quantify effects of no post-infiltration soil aeration versus aeration during 5 different periods (namely 27-33, 34-57, 58-85, 86-99, and 27-99 days after sowing), on growth and fruit quality of potted single tomato plants that were sub-surface trickle-irrigated every 2 days at 2 levels. Soil was aerated by injecting 2.5 liters of air into each pot through the drip tubing immediately after irrigation. Results showed that post-infiltration aeration, especially during the fruit setting (34-57 DAS) and enlargement (58-85 DAS) growth stages, can positively influence the yield, root dry weight and activity, and the nutritional (soluble solids and vitamin C content), taste (titratable acidity), and market quality (shape and firmness) of the tomato fruits. Interactions between irrigation level and post-infiltration aeration on some of these fruit quality parameters indicated a need for further study on the dynamic interplay of air and water in the root zone of the plants under the conditions of this experiment.

Improving soil moisture simulation to support Agricultural Water Resource Management using Satellite-based water cycle observations

NASA Astrophysics Data System (ADS)

Gupta, Manika; Bolten, John; Lakshmi, Venkat

2016-04-01

Efficient and sustainable irrigation systems require optimization of operational parameters such as irrigation amount which are dependent on the soil hydraulic parameters that affect the model's accuracy in simulating soil water content. However, it is a scientific challenge to provide reliable estimates of soil hydraulic parameters and irrigation estimates, given the absence of continuously operating soil moisture and rain gauge network. For agricultural water resource management, the in-situ measurements of soil moisture are currently limited to discrete measurements at specific locations, and such point-based measurements do not represent the spatial distribution at a larger scale accurately, as soil moisture is highly variable both spatially and temporally (Wang and Qu 2009). In the current study, flood irrigation scheme within the land surface model is triggered when the root-zone soil moisture deficit reaches below a threshold of 25%, 50% and 75% with respect to the maximum available water capacity (difference between field capacity and wilting point) and applied until the top layer is saturated. An additional important criterion needed to activate the irrigation scheme is to ensure that it is irrigation season by assuming that the greenness vegetation fraction (GVF) of the pixel exceed 0.40 of the climatological annual range of GVF (Ozdogan et al. 2010). The main hypothesis used in this study is that near-surface remote sensing soil moisture data contain useful information that can describe the effective hydrological conditions of the basin such that when appropriately inverted, it would provide field capacity and wilting point soil moisture, which may be representative of that basin. Thus, genetic algorithm inverse method is employed to derive the effective parameters and derive the soil moisture deficit for the root zone by coupling of AMSR-E soil moisture with the physically based hydrological model. Model performance is evaluated using MODIS-evapotranspiration (ET) and MODIS land surface temperature (LST) products. The soil moisture estimates for the root zone are also validated with the in-situ field data, for three sites (2- irrigated and 1- rainfed) located at the University of Nebraska Agricultural Research and Development Center near Mead, NE and monitored by three AmeriFlux installations (Verma et al., 2005) by evaluating the root mean square error (RMSE) and Mean Bias error (MBE).

Holistic irrigation water management approach based on stochastic soil water dynamics

NASA Astrophysics Data System (ADS)

Alizadeh, H.; Mousavi, S. J.

2012-04-01

Appreciating the essential gap between fundamental unsaturated zone transport processes and soil and water management due to low effectiveness of some of monitoring and modeling approaches, this study presents a mathematical programming model for irrigation management optimization based on stochastic soil water dynamics. The model is a nonlinear non-convex program with an economic objective function to address water productivity and profitability aspects in irrigation management through optimizing irrigation policy. Utilizing an optimization-simulation method, the model includes an eco-hydrological integrated simulation model consisting of an explicit stochastic module of soil moisture dynamics in the crop-root zone with shallow water table effects, a conceptual root-zone salt balance module, and the FAO crop yield module. Interdependent hydrology of soil unsaturated and saturated zones is treated in a semi-analytical approach in two steps. At first step analytical expressions are derived for the expected values of crop yield, total water requirement and soil water balance components assuming fixed level for shallow water table, while numerical Newton-Raphson procedure is employed at the second step to modify value of shallow water table level. Particle Swarm Optimization (PSO) algorithm, combined with the eco-hydrological simulation model, has been used to solve the non-convex program. Benefiting from semi-analytical framework of the simulation model, the optimization-simulation method with significantly better computational performance compared to a numerical Mote-Carlo simulation-based technique has led to an effective irrigation management tool that can contribute to bridging the gap between vadose zone theory and water management practice. In addition to precisely assessing the most influential processes at a growing season time scale, one can use the developed model in large scale systems such as irrigation districts and agricultural catchments. Accordingly, the model has been applied in Dasht-e-Abbas and Ein-khosh Fakkeh Irrigation Districts (DAID and EFID) of the Karkheh Basin in southwest of Iran. The area suffers from the water scarcity problem and therefore the trade-off between the level of deficit and economical profit should be assessed. Based on the results, while the maximum net benefit has been obtained for the stress-avoidance (SA) irrigation policy, the highest water profitability, defined by economical net benefit gained from unit irrigation water volume application, has been resulted when only about 60% of water used in the SA policy is applied.

Soil water sensing: Implications of sensor capabilities for variable rate irrigation management

USDA-ARS?s Scientific Manuscript database

Irrigation scheduling using soil water sensors aims at maintaining the soil water content in the crop root zone above a lower limit defined by the management allowed depletion (MAD) for that soil and crop, but not so wet that too much water is lost to deep percolation, evaporation and runoff or that...

Sensing water from subsurface drip irrigation laterals: In situ sensors, weighing lysimeters and COSMOS under vegetated and bare conditions

USDA-ARS?s Scientific Manuscript database

Characterization of soil water dynamics in the root zone under subsurface drip irrigated (SDI) is complicated by the three dimensional nature of water fluxes from drip emitters plus the fluxes, if any, of water from precipitation. In addition, soil water sensing systems may differ in their operating...

Variation in Adult Plant Phenotypes and Partitioning among Seed and Stem-Borne Roots across Brachypodium distachyon Accessions to Exploit in Breeding Cereals for Well-Watered and Drought Environments.

PubMed

Chochois, Vincent; Vogel, John P; Rebetzke, Gregory J; Watt, Michelle

2015-07-01

Seedling roots enable plant establishment. Their small phenotypes are measured routinely. Adult root systems are relevant to yield and efficiency, but phenotyping is challenging. Root length exceeds the volume of most pots. Field studies measure partial adult root systems through coring or use seedling roots as adult surrogates. Here, we phenotyped 79 diverse lines of the small grass model Brachypodium distachyon to adults in 50-cm-long tubes of soil with irrigation; a subset of 16 lines was droughted. Variation was large (total biomass, ×8; total root length [TRL], ×10; and root mass ratio, ×6), repeatable, and attributable to genetic factors (heritabilities ranged from approximately 50% for root growth to 82% for partitioning phenotypes). Lines were dissected into seed-borne tissues (stem and primary seminal axile roots) and stem-borne tissues (tillers and coleoptile and leaf node axile roots) plus branch roots. All lines developed one seminal root that varied, with branch roots, from 31% to 90% of TRL in the well-watered condition. With drought, 100% of TRL was seminal, regardless of line because nodal roots were almost always inhibited in drying topsoil. Irrigation stimulated nodal roots depending on genotype. Shoot size and tillers correlated positively with roots with irrigation, but partitioning depended on genotype and was plastic with drought. Adult root systems of B. distachyon have genetic variation to exploit to increase cereal yields through genes associated with partitioning among roots and their responsiveness to irrigation. Whole-plant phenotypes could enhance gain for droughted environments because root and shoot traits are coselected. © 2015 American Society of Plant Biologists. All Rights Reserved.

Land Retirement as a Habitat Restoration Tool

NASA Astrophysics Data System (ADS)

Singh, P. N.; Wallender, W. W.

2007-12-01

Use of intensive irrigation in arid and semi-arid areas usually leads to gradual salination of the soil leading to crop yield decline. The salination problem is mitigated by applying irrigation in excess of crop requirements, which leaches the excess salt load to the groundwater. Insufficient natural or man made drainage to dispose off this saline recharge to the groundwater leads to a gradual rise in the water table and eventual encroachment upon the root zone. This may ultimately make the land unfit for any economically productive activity. The abandoned land may even lead to desertification with adverse environmental consequences. In drainage basins with no surface outflow (sometimes called closed basins), land retirement has been proposed as a management tool to address this problem. Land retirement essentially entails intentionally discontinuing irrigation of selected farmlands with the expectation that the shallow water table beneath those lands should drop and the root zone salinity level should decrease. In the San Joaquin Valley of California, intensive irrigation in conjunction with a shallow underlying layer of clay, known as the Corcoran clay layer and absence of a drainage system caused the root zone to become highly saline and the shallow water table to rise. Land retirement would remove from production those farmlands contributing the poorest quality subsurface drain water. Based on numerical models results, it was expected that with land retirement of substantial irrigated lands with poor drainage characteristics, beneath which lies shallow groundwater with high salt load, the shallow water table beneath those lands should drop. A part of the retired lands could also be used for wildlife habitat. A potential negative side of the land retirement option that has to be considered is that in certain enabling evapotranspiration, soil and water table conditions, water will be drawn upwards and evaporated, leaving a deposit of salts on the surface and in the root zone. Salt on the surface may then be wind blown to adjacent areas creating a potential environmental hazard. Using field results from the U.S. Department of the Interior Land Retirement Demonstration Project at the Tranquillity site located in western Fresno County, principles of mass balance in a fixed control volume, the HYDRUS-1D Software Package for Simulating the One-Dimensional Movement of Water, Heat, and Multiple Solutes in Variably-Saturated Media, and PEST, a model-independent parameter optimizer, we have investigated the processes of soil water and salinity movement in the root zone and the deep vadose zone. Various combinations of evapotranspiration, soil water retention properties, water table condition and top and bottom boundary condition were tested. We show that certain Land Retirement scenarios decrease shallow water table and soil water salinity and enhance development of native plants as a means to facilitate habitat restoration for certain combination of soil and bottom boundary condition. Other combinations are not sustainable.

Untangling the effects of shallow groundwater and deficit irrigation on irrigation water productivity in arid region: New conceptual model.

PubMed

Xue, Jingyuan; Huo, Zailin; Wang, Fengxin; Kang, Shaozhong; Huang, Guanhua

2018-04-01

Water scarcity and salt stress are two main limitations for agricultural production. Groundwater evapotranspiration (ET g ) with upward salt movement plays an important role in crop water use and water productivity in arid regions, and it can compensate the impact of deficit irrigation on crop production. Thus, comprehensive impacts of shallow groundwater and deficit irrigation on crop water use results in an improvement of irrigation water productivity (IWP). However, it is difficult to quantify the effects of groundwater and deficit irrigation on IWP. In this study, we built an IWP evaluation model coupled with a water and salt balance model and a crop yield estimation model. As a valuable tool of IWP simulation, the calibrated model was used to investigate the coupling response of sunflower IWP to irrigation water depths (IWDs), groundwater table depth (GTDs) and groundwater salinities (GSs). A total of 210 scenarios were run in which five irrigation water depths (IWDs) and seven groundwater table depths (GTDs) and six groundwater salinities (GSs) were used. Results indicate that increasing GS clearly increases the negative effect on a crop's actual evapotranspiration (ET a ) as salt accumulation in root zone. When GS is low (0.5-1g/L), increasing GTD produces more positive effect than negative effect. In regard to relatively high GS (2-5g/L), the negative effect of shallow-saline groundwater reaches a maximum at 2m GTD. Additionally, the salt concentration in the root zone maximizes its value at 2.0m GTD. In most cases, increasing GTD and GS reduces the benefits of irrigation water and IWP. The IWP increases with decreasing irrigation water. Overall, in arid regions, capillary rise of shallow groundwater can compensate for the lack of irrigation water and improve IWP. By improving irrigation schedules and taking advantages of shallow saline groundwater, we can obtain higher IWP. Copyright © 2017 Elsevier B.V. All rights reserved.

Potentials and problems of sustainable irrigation with water high in salts

NASA Astrophysics Data System (ADS)

Ben-Gal, Alon

2015-04-01

Water scarcity and need to expand agricultural productivity have led to ever growing utilization of poor quality water for irrigation of crops. Almost in all cases, marginal or alternative water sources for irrigation contain relatively high concentrations of dissolved salts. When salts are present, irrigation water management, especially in the dry regions where water requirements are highest, must consider leaching in addition to crop evapotranspiration requirements. Leaching requirements for agronomic success are calculable and functions of climate, soil, and very critically, of crop sensitivity and the actual salinity of the irrigation water. The more sensitive the crop and more saline the water, the higher the agronomic cost and the greater the quantitative need for leaching. Israel is a forerunner in large-scale utilization of poor quality water for irrigation and can be used as a case study looking at long term repercussions of policy alternatively encouraging irrigation with recycled water or brackish groundwater. In cases studied in desert conditions of Israel, as much of half of the water applied to crops including bell peppers in greenhouses and date palms is actually used to leach salts from the root zone. The excess water used to leach salts and maintain agronomic and economic success when irrigating with water containing salts can become an environmental hazard, especially in dry areas where natural drainage is non-existent. The leachate often contains not only salts but also agrochemicals including nutrients, and natural contaminants can be picked up and transported as well. This leachate passes beyond the root zone and eventually reaches ground or surface water resources. This, together with evidence of ongoing increases in sodium content of fresh produce and increased SAR levels of soils, suggest that the current policy and practice in Israel of utilization of high amounts of low quality irrigation water is inherently non- sustainable. Current trends and technologies allowing economically feasible desalination at large scales present a sustainable alternative where salts are removed from water prior to irrigation.

Soil moisture dynamics modeling considering multi-layer root zone.

PubMed

Kumar, R; Shankar, V; Jat, M K

2013-01-01

The moisture uptake by plant from soil is a key process for plant growth and movement of water in the soil-plant system. A non-linear root water uptake (RWU) model was developed for a multi-layer crop root zone. The model comprised two parts: (1) model formulation and (2) moisture flow prediction. The developed model was tested for its efficiency in predicting moisture depletion in a non-uniform root zone. A field experiment on wheat (Triticum aestivum) was conducted in the sub-temperate sub-humid agro-climate of Solan, Himachal Pradesh, India. Model-predicted soil moisture parameters, i.e., moisture status at various depths, moisture depletion and soil moisture profile in the root zone, are in good agreement with experiment results. The results of simulation emphasize the utility of the RWU model across different agro-climatic regions. The model can be used for sound irrigation management especially in water-scarce humid, temperate, arid and semi-arid regions and can also be integrated with a water transport equation to predict the solute uptake by plant biomass.

Long term agronomic and environmental effects of irrigation with reclaimed wastewater

NASA Astrophysics Data System (ADS)

Yermiyahu, Uri; Ben-Gal, Alon; Dag, Arnon

2014-05-01

Fresh water in the Mediterranean region is generally scarce and only low quality reclaimed wastewater (RWW) is available for irrigation. The aim of the present study was to evaluate the effect of irrigation with RWW on tree growth and productivity and to quantify nitrate and chloride (Cl) losses in an olive orchard. Three treatments were tested on two cultivars (Barnea and Leccino); fresh water with standard fertigation (Fr), recycled water with standard fertigation (Re) and recycled water with reduced fertigation (in accordance to the K and N available in the recycled water) (Re-). The total amount of nutrients arriving with the RWW was substantial; 100, 30, 150 kg ha-1 N, P, K, respectively, ca. half of the recommended fertilization dosages. Throughout the 6 experimental years, fertigation treatments did not influence nutrient status in leaves and did not affect fruit or oil production. While similar amounts of water were applied, the Re and Re- treatments loaded the soil profile with 1.75 times more Cl than the Fr treatment. Additionally, significantly more nitrates were transported out of the root zone in the Re treatment compared to Fr and Re- for both cultivars. The results indicate that recycled water can be used for olive oil irrigation with no negative effects on oil yield or quality. Irrigation with RWW increased salt loads into and beyond the root zone. The nutritional constituents in the RWW used to irrigate olives should be accounted for in order to increase fertilizer application efficiency and minimize the transport of salts and nutrients into groundwater.

User guide for the farm process (FMP1) for the U.S. Geological Survey's modular three-dimensional finite-difference ground-water flow model, MODFLOW-2000

USGS Publications Warehouse

Schmid, Wolfgang; Hanson, R.T.; Maddock, Thomas; Leake, S.A.

2006-01-01

There is a need to estimate dynamically integrated supply-and-demand components of irrigated agriculture as part of the simulation of surface-water and ground-water flow. To meet this need, a computer program called the Farm Process (FMP1) was developed for the U.S. Geological Survey three-dimensional finite-difference modular ground-water flow model, MODFLOW- 2000 (MF2K). The FMP1 allows MF2K users to simulate conjunctive use of surface- and ground water for irrigated agriculture for historical and future simulations, water-rights issues and operational decisions, nondrought and drought scenarios. By dynamically integrating farm delivery requirement, surface- and ground-water delivery, as well as irrigation-return flow, the FMP1 allows for the estimation of supplemental well pumpage. While farm delivery requirement and irrigation return flow are simulated by the FMP1, the surface-water delivery to the farm can be simulated optionally by coupling the FMP1 with the Streamflow Routing Package (SFR1) and the farm well pumping can be simulated optionally by coupling the FMP1 to the Multi-Node Well (MNW) Package. In addition, semi-routed deliveries can be specified that are associated with points of diversion in the SFR1 stream network. Nonrouted surface-water deliveries can be specified independently of any stream network. The FMP1 maintains a dual mass balance of a farm budget and as part of the ground-water budget. Irrigation demand, supply, and return flow are in part subject to head-dependent sources and sinks such as evapotranspiration from ground water and leakage between the conveyance system and the aquifer. Farm well discharge and farm net recharge are source/sink terms in the FMP1, which depend on transpiration uptake from ground water and other head dependent consumptive use components. For heads rising above the bottom of the root zone, the actual transpiration is taken to vary proportionally with the depth of the active root zone, which can be restricted by anoxia or wilting. Depths corresponding to anoxia- or wilting-related pressure heads within the root zone are found using analytical solutions of a vertical pseudo steady-state pressure- head distribution over the depth of the total root zone (Consumptive Use Concept 1). Alternatively, a simpler, conceptual model is available, which defines how consumptive use (CU) components vary with changing head (CU Concept 2). Subtracting the ground water and precipitation transpiration components from the total transpiration yields a transpiratory irrigation requirement for each cell. The total farm delivery requirement (TFDR) then is determined as cumulative transpiratory and evaporative irrigation requirements of all farm cells and increased sufficiently to compensate for inefficient use from irrigation with respect to plant consumption. The TFDR subsequently is satisfied with surface- and ground-water delivery, respectively constrained by allotments, water rights, or maximum capacities. Five economic and noneconomic drought response policies can be applied optionally, if the potential supply of surface water and ground water is insufficient to meet the crop demand: acreage-optimization with or without a water conservation pool, deficit irrigation with or without water-stacking, and zero policy.

Relative Water Uptake as a Criterion for the Design of Trickle Irrigation Systems

NASA Astrophysics Data System (ADS)

Communar, G.; Friedman, S. P.

2008-12-01

Previously derived analytical solutions to the 2- and 3-dimensional water flow problems describing trickle irrigation are not being widely used in practice because those formulations either ignore root water uptake or refer to it as a known input. In this lecture we are going to describe a new modeling approach and demonstrate its applicability for designing the geometry of trickle irrigation systems, namely the spacing between the emitters and drip lines. The major difference between our and previous modeling approaches is that we refer to the root water uptake as to the unknown solution of the problem and not as to a known input. We postulate that the solution to the steady-state water flow problem with a root sink that is acting under constant, maximum suction defines un upper bound to the relative water uptake (water use efficiency) in actual transient situations and propose to use it as a design criterion. Following previous derivations of analytical solutions we assume that the soil hydraulic conductivity increases exponentially with its matric head, which allows the linearization of the Richards equation, formulated in terms of the Kirchhoff matric flux potential. Since the transformed problem is linear, the relative water uptake for any given configuration of point or line sources and sinks can be calculated by superposition of the Green's functions of all relevant water sources and sinks. In addition to evaluating the relative water uptake, we also derived analytical expressions for the steam functions. The stream lines separating the water uptake zone from the percolating water provide insight to the dependence of the shape and extent of the actual rooting zone on the source- sink geometry and soil properties. A minimal number of just 3 system parameters: Gardner's (1958) alfa as a soil type quantifier and the depth and diameter of the pre-assumed active root zone are sufficient to characterize the interplay between capillary and gravitational effects on water flow and the competition between the processes of root water uptake and percolation. For accounting also for evaporation from the soil surface, when significant, another parameter is required, adopting the solution of Lomen and Warrick (1978).

A Scanning Electron Microscope Evaluation of Smear Layer Removal and Antimicrobial Action of Mixture of Tetracycline, Acid and Detergent, Sodium Hypochlorite, Ethylenediaminetetraacetic Acid, and Chlorhexidine Gluconate: An In vitro Study.

PubMed

Charlie, K M; Kuttappa, M A; George, Liza; Manoj, K V; Joseph, Bobby; John, Nishin K

2018-01-01

The main objective is to evaluate the efficiency in removal of smear layer of mixture of tetracycline, acid and detergent (MTAD), sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA) and chlorhexidine gluconate by scanning electron microscope (SEM) evaluation and also to evaluate the antimicrobial action of the same irrigants against standard culture strains of Enterococcus faecalis . This study included 60 extracted permanent teeth with single root canal. The sample was categorized into five groups with 12 teeth in each group. Root canals were enlarged till size 40 with K-files. One group was kept as control and irrigated only with saline. Other four groups used 5% NaOCl as irrigant during instrumentation and MTAD, 5% NaOCl, 17% EDTA, and 2% chlorhexidine gluconate as final rinse. Teeth were split and examined under SEM. To test the antibacterial action, the zone of inhibition method using agar plates was used. Obtained data were statistically analyzed by SPSS version 17 (SPSS Inc., Chicago, IL, USA). MTAD and 17% EDTA removed smear layer from all regions of the root canals. About 5% NaOCl and 2% chlorhexidine gluconate were ineffective in removing the smear layer. The mean zone of inhibition formed by the irrigants was in the following order; MTAD (40.5 mm), 2% chlorhexidine gluconate (29.375 mm), 17% EDTA (24.125 mm), 5% NaOCl (22.125 mm), and saline (zero). MTAD showed high smear layer removal efficacy, but no significant difference was found to that of 17% EDTA. As the dimensions of the zones of inhibition showed, MTAD has got highest antibacterial action against E. faecalis , followed by 2% chlorhexidine gluconate, 17% EDTA, and 5% NaOCl. However, the exact correlation of in vitro study results to clinical conditions is impossible due to the variables involved.

Matching agricultural freshwater supply and demand: using industrial and domestic treated wastewater for sub-irrigation purposes

NASA Astrophysics Data System (ADS)

Bartholomeus, Ruud; van den Eertwegh, Gé; Worm, Bas; Cirkel, Gijsbert; van Loon, Arnaut; Raat, Klaasjan

2017-04-01

Agricultural crop yields depend largely on soil moisture conditions in the root zone. Climate change leads to more prolonged drought periods that alternate with more intensive rainfall events. With unaltered water management practices, reduced crop yield due to drought stress will increase. Therefore, both farmers and water management authorities search for opportunities to manage risks of decreasing crop yields. Available groundwater sources for irrigation purposes are increasingly under pressure due to the regional coexistence of land use functions that are critical to groundwater levels or compete for available water. At the same time, treated wastewater from industries and domestic wastewater treatment plants are quickly discharged via surface waters towards sea. Exploitation of these freshwater sources may be an effective strategy to balance regional water supply and agricultural water demand. We present results of two pilot studies in drought sensitive regions in the Netherlands, concerning agricultural water supply through reuse of industrial and domestic treated wastewater. In these pilots, excess wastewater is delivered to the plant root zone through sub-irrigation by drainage systems. Sub-irrigation is a subsurface irrigation method that can be more efficient than classical, aboveground irrigation methods using sprinkler installations. Domestic wastewater treatment plants in the Netherlands produce annually 40-50mm freshwater. A pilot project has been setup in the eastern part of the Netherlands, in which treated wastewater is applied to a corn field by sub-irrigation during the growing seasons of 2015 and 2016, using a climate adaptive drainage system. The chemical composition of treated domestic wastewater is different from infiltrating excess rainfall water and natural groundwater. In the pilot project, the bromide-chloride ratio and traces of pharmaceuticals in the treated wastewater are used as a tracer to describe water and solute transport in the soil system. Focus of this pilot study is on quantifying potential contamination of both the root zone and the deeper groundwater with pharmaceutical residues. We have installed a field monitoring network at several locations in the vadose zone and the local groundwater system, which enables us to measure vertical solute profiles in the soil water by taking samples. Based on field data obtained during the experiments, combined with SWAP (1D) and Hydrus (2D) model simulations, flow and transport of the sub-irrigated treated wastewater are quantified. In the south of The Netherlands, the Bavaria Beer Brewery abstracts a large volume of groundwater and discharges treated wastewater to local surface water which transports the water rapidly out of the region. At the same time, neighboring farmers invest in sprinkler irrigation systems to maintain their crop production during drought periods. In this region, increasing pressure is put on the regional groundwater and surface water availability. Within a pilot study, a sub-irrigation system has been installed, by using subsurface drains, interconnected through a collector drain, and connected to an inlet control basin for the treated wastewater to enter the drainage system. We combine both process-based modeling of the soil-plant-atmosphere system and field experiments to i) investigate the amount of water that needs to be and that can be sub-irrigated, and ii) quantify the effect on soil moisture availability and herewith reduced needs for aboveground irrigation.

Comparative evaluation of antimicrobial activity of hydroalcoholic extract of Aloe vera, garlic, and 5% sodium hypochlorite as root canal irrigants against Enterococcus faecalis: An in vitro study.

PubMed

Karkare, Swati Ramesh; Ahire, Nivedita Pramod; Khedkar, Smita Uday

2015-01-01

Enterococcus faecalis are the most resistant and predominant microorganisms recovered from root canals of teeth where previous treatment has failed. Over the past decade, interest in drugs derived from medicinal plants has markedly increased. In dentistry, phytomedicines has been used as an anti-inflammatory, antibiotic, analgesic, sedative, and also as an endodontic irrigant. In endodontics, because of the cytotoxic reactions of most of the commercial intracanal medicaments and their inability to eliminate bacteria completely from dentinal tubules, the trend is shifting toward use of biologic medication extracted from natural plants. To compare the antimicrobial efficacy of newer irrigating agents which would probably be as effective or more and at the same time less irritating to the tissues than sodium hypochlorite (NaOCl). The objective of this study was to compare the antimicrobial activity of saturated and diluted (1:1) hydroalcoholic extract of Aloe vera, garlic, and 5% NaOCl against E. faecalis using the commonly used agar diffusion method. Saturated hydroalcoholic extract of A. vera showed the highest zone of inhibition against E. faecalis. NaOCl, which is considered as gold standard, also showed higher zones of inhibition.

Models for root water uptake under deficit irrigation

NASA Astrophysics Data System (ADS)

Lazarovitch, Naftali; Krounbi, Leilah; Simunek, Jirka

2010-05-01

Modern agriculture, with its dependence on irrigation, fertilizers, and pesticide application, contributes significantly to the water and solute influx through the soil into the groundwater, specifically in arid areas. The quality and quantity of this water as it passes through the vadose zone is influenced primarily by plant roots. Root water uptake is a function of both a physical root parameter, commonly referred to as the root length density, and the soil water status. The location of maximum water uptake in a homogenous soil profile of uniform water content and hydraulic conductivity occurs in the soil layer containing the largest root length density. Under field conditions, in a drying soil, plants are both subject to, and the source of, great spatial variability in the soil water content. The upper soil layers containing the bulk of the root zone are usually the most water depleted, while the deeper regions of the soil profile containing fewer roots are wetter. Changes in the physiological functioning of plants have been shown to result from extended periods of water stress, but the short term effects of water stress on root water uptake are less well understood. While plants can minimize transpiration and the resulting growth rates under limiting conditions to conserve water, many plants maintain a constant potential transpiration rate long after the commencement of the drying process. Compensatory uptake, whereby plants respond to non-uniform, limiting conditions by increasing water uptake from areas in the root zone characterized by more favorable conditions, is one such mechanism by which plants sustain potential transpiration rates in drying soils. The development of models which accurately characterize temporal and spatial root water uptake patterns is important for agricultural resource optimization, upon which subsequent management decisions affecting resource conservation and environmental pollution are based. Numerical simulations of root water uptake in various irrigation and fertilization regimes provide a much-needed alternative to tiring and expensive field work. These simulations can aid in raising agricultural water use efficiency while preserving soil and water resources. In this research, controlled lab experiments were carried out in soil-packed lysimeters designed for plant cultivation. Both the water balance of the growing plants as well as the temporary matric head distribution in the soil profile were calculated and measured. The experiment was conducted with sweet sorghum grown in two different soil profiles with different hydraulic properties. The experiment provided the data necessary to calculate the parameters of various models used to simulate root water uptake, by using an inverse solution method imbedded in the HYDRUS-1D code. The observed increase in uptake from the wetter soil regions under drying conditions, as measured and calculated, sheds light on the dominant role of soil hydraulic properties over the root distribution, and consequently root water uptake.

Comparison of simulations of land-use specific water demand and irrigation water supply by MF-FMP and IWFM

USGS Publications Warehouse

Schmid, Wolfgang; Dogural, Emin; Hanson, Randall T.; Kadir, Tariq; Chung, Francis

2011-01-01

Two hydrologic models, MODFLOW with the Farm Process (MF-FMP) and the Integrated Water Flow Model (IWFM), are compared with respect to each model’s capabilities of simulating land-use hydrologic processes, surface-water routing, and groundwater flow. Of major concern among the land-use processes was the consumption of water through evaporation and transpiration by plants. The comparison of MF-FMP and IWFM was conducted and completed using a realistic hypothetical case study. Both models simulate the water demand for water-accounting units resulting from evapotranspiration and inefficiency losses and, for irrigated units, the supply from surface-water deliveries and groundwater pumpage. The MF-FMP simulates reductions in evapotranspiration owing to anoxia and wilting, and separately considers land-use-related evaporation and transpiration; IWFM simulates reductions in evapotranspiration related to the depletion of soil moisture. The models simulate inefficiency losses from precipitation and irrigation water applications to runoff and deep percolation differently. MF-FMP calculates the crop irrigation requirement and total farm delivery requirement, and then subtracts inefficiency losses from runoff and deep percolation. In IWFM, inefficiency losses to surface runoff from irrigation and precipitation are computed and subtracted from the total irrigation and precipitation before the crop irrigation requirement is estimated. Inefficiency losses in terms of deep percolation are computed simultaneously with the crop irrigation requirement. The seepage from streamflow routing also is computed differently and can affect certain hydrologic settings and magnitudes ofstreamflow infiltration. MF-FMP assumes steady-state conditions in the root zone; therefore, changes in soil moisture within the root zone are not calculated. IWFM simulates changes in the root zone in both irrigated and non-irrigated natural vegetation. Changes in soil moisture are more significant for non-irrigated natural vegetation areas than in the irrigated areas. Therefore, to facilitate the comparison of models, the changes in soil moisture are only simulated by IWFM for the natural vegetation areas, and soil-moisture parameters in irrigated regions in IWFM were specified at constant values . The IWFM total simulated changes in soil moisture that are related to natural vegetation areas vary from stress period to stress period but are small over the entire two-year period of simulation. In the hypothetical case study, IWFM simulates more evapotranspiration and return flows and less streamflow infiltration than MF-FMP. This causes more simulated surface-water diversions upstream and less simulated water available to downstream farms in IWFM compared to MF-FMP. The evapotranspiration simulated by the two models is well correlated even though the quantity is different. The different approaches used to simulate soil moisture, evapotranspiration, and inefficient losses yield different results for deep percolation and pumpage. In IWFM, deep percolation is a function of soil moisture; therefore, the constant soil-moisture requirement for irrigated regions, assumed for this comparison, results in a constant deep percolation rate. This led to poor correlation with the variable deep percolation rates simulated in MF-FMP, where the deep percolation rate, a fraction of inefficiency losses from precipitation and irrigation, is a function of quasi-steady state infiltration for each soil type and a function of groundwater head. Similarly, the larger simulated evapotranspiration in IWFM is mainly responsible for larger simulated groundwater pumpage demands and related lower groundwater levels in IWFM compared to MF-FMP. Because of the differences in features between MF-FMP and IWFM, the user may find that for certain hydrologic settings one model is better suited than the other. The performance of MF-FMP and IWFM in this particular hypothetical test case, with a fixed framework composed of common initial and boundary conditions and input parameter values, does not necessarily predict the performance of MF-FMP and IWFM in a real-world situation with variable framework and parameter values. These differences may affect the evaluation of policies, projects, or water-balance analysis for some hydrologic settings. Generally, both models are powerful tools that simulate a connected system of aquifer, stream networks, land surface, root zone, and runoff processes. MF-FMP simulated the hypothetical test case in about 4 minutes compared to about 58 minutes for IWFM.

Evaluation of Crop-Water Consumption Simulation to Support Agricultural Water Resource Management using Satellite-based Water Cycle Observations

NASA Astrophysics Data System (ADS)

Gupta, M.; Bolten, J. D.; Lakshmi, V.

2016-12-01

Water scarcity is one of the main factors limiting agricultural development. Numerical models integrated with remote sensing datasets are increasingly being used operationally as inputs for crop water balance models and agricultural forecasting due to increasing availability of high temporal and spatial resolution datasets. However, the model accuracy in simulating soil water content is affected by the accuracy of the soil hydraulic parameters used in the model, which are used in the governing equations. However, soil databases are known to have a high uncertainty across scales. Also, for agricultural sites, the in-situ measurements of soil moisture are currently limited to discrete measurements at specific locations, and such point-based measurements do not represent the spatial distribution at a larger scale accurately, as soil moisture is highly variable both spatially and temporally. The present study utilizes effective soil hydraulic parameters obtained using a 1-km downscaled microwave remote sensing soil moisture product based on the NASA Advanced Microwave Scanning Radiometer (AMSR-E) using the genetic algorithm inverse method within the Catchment Land Surface Model (CLSM). Secondly, to provide realistic irrigation estimates for agricultural sites, an irrigation scheme within the land surface model is triggered when the root-zone soil moisture deficit reaches the threshold, 50% with respect to the maximum available water capacity obtained from the effective soil hydraulic parameters. An additional important criterion utilized is the estimation of crop water consumption based on dynamic root growth and uptake in root zone layer. Model performance is evaluated using MODIS land surface temperature (LST) product. The soil moisture estimates for the root zone are also validated with the in situ field data, for three sites (2- irrigated and 1- rainfed) located at the University of Nebraska Agricultural Research and Development Center near Mead, NE and monitored by three AmeriFlux installations (Verma et al., 2005).

Application of time-lapse ERT to Characterize Soil-Water-Disease Interactions of Citrus Orchard - Case Study

NASA Astrophysics Data System (ADS)

Peddinti, S. R.; Kbvn, D. P.; Ranjan, S.; Suradhaniwar, S.; J, P. A.; R M, G.

2015-12-01

Vidarbha region in Maharashtra, India (home for mandarin Orange) experience severe climatic uncertainties resulting in crop failure. Phytopthora are the soil-borne fungal species that accumulate in the presence of moisture, and attack the root / trunk system of Orange trees at any stage. A scientific understanding of soil-moisture-disease relations within the active root zone under different climatic, irrigation, and crop cycle conditions can help in practicing management activities for improved crop yield. In this study, we developed a protocol for performing 3-D time-lapse electrical resistivity tomography (ERT) at micro scale resolution to monitor the changes in resistivity distribution within the root zone of Orange trees. A total of 40 electrodes, forming a grid of 3.5 m x 2 m around each Orange tree were used in ERT survey with gradient and Wenner configurations. A laboratory test on un-disturbed soil samples of the region was performed to plot the variation of electrical conductivity with saturation. Curve fitting techniques were applied to get the modified Archie's model parameters. The calibrated model was further applied to generate the 3-D soil moisture profiles of the study area. The point estimates of soil moisture were validated using TDR probe measurements at 3 different depths (10, 20, and 40 cm) near to the root zone. In order to understand the effect of soil-water relations on plant-disease relations, we performed ERT analysis at two locations, one at healthy and other at Phytopthora affected Orange tree during the crop cycle, under dry and irrigated conditions. The degree to which an Orange tree is affected by Phytopthora under each condition is evaluated using 'grading scale' approach following visual inspection of the canopy features. Spatial-temporal distribution of moisture profiles is co-related with grading scales to comment on the effect of climatic and irrigation scenarios on the degree and intensity of crop disease caused by Phytopthora.

Water consumption and water-saving characteristics of a ground cover rice production system

NASA Astrophysics Data System (ADS)

Jin, Xinxin; Zuo, Qiang; Ma, Wenwen; Li, Sen; Shi, Jianchu; Tao, Yueyue; Zhang, Yanan; Liu, Yang; Liu, Xiaofei; Lin, Shan; Ben-Gal, Alon

2016-09-01

The ground cover rice production system (GCRPS) offers a potentially water-saving alternative to the traditional paddy rice production system (TPRPS) by furrow irrigating mulched soil beds and maintaining soils under predominately unsaturated conditions. The guiding hypothesis of this study was that a GCRPS would decrease both physiological and non-physiological water consumption of rice compared to a TPRPS while either maintaining or enhancing production. This was tested in a two-year field experiment with three treatments (TPRPS, GCRPSsat keeping root zone average soil water content near saturated, and GCRPS80% keeping root zone average soil water content as 80-100% of field water capacity) and a greenhouse experiment with four treatments (TPRPS, GCRPSsat, GCRPSfwc keeping root zone average soil water content close to field water capacity, and GCRPS80%). The water-saving characteristics of GCRPS were analyzed as a function of the measured soil water conditions, plant parameters regarding growth and production, and water input and consumption. In the field experiment, significant reduction in both physiological and non-physiological water consumption under GCRPS lead to savings in irrigation water of ∼61-84% and reduction in total input water of ∼35-47%. Compared to TPRPS, deep drainage was reduced ∼72-88%, evaporation was lessened ∼83-89% and transpiration was limited ∼6-10% under GCRPS. In addition to saving water, plant growth and grain yield were enhanced under GCRPS due to increased soil temperature in the root zone. Therefore, water use efficiencies (WUEs), based on transpiration, irrigation and total input water, were respectively improved as much as 27%, 609% and 110% under GCRPS. Increased yield attributed to up to ∼19%, decreased deep drainage accounted for ∼75%, decreased evaporation accounted for ∼14% and reduced transpiration for ∼5% of the enhancement in WUE of input water under GCRPS, while increased runoff and water storage had negative influence on WUE (-7.5 and -3.7%, respectively) for GCRPS compared to TPRPS. The greenhouse experiment validated the results obtained in the field by simplifying the non-physiological water consumption processes, and thus confirming the relative importance of physiological processes and increased WUE under GCRPS.

[Effects of soil wetting pattern on the soil water-thermal environment and cotton root water consumption under mulched drip irrigation].

PubMed

Li, Dong-wei; Li, Ming-si; Liu, Dong; Lyu, Mou-chao; Jia, Yan-hui

2015-08-01

Abstract: To explore the effects of soil wetting pattern on soil water-thermal environment and water consumption of cotton root under mulched drip irrigation, a field experiment with three drip intensities (1.69, 3.46 and 6.33 L · h(-1)), was carried out in Shihezi, Xinjiang Autonomous Region. The soil matric potential, soil temperature, cotton root distribution and water consumption were measured during the growing period of cotton. The results showed that the main factor influencing the soil temperature of cotton under plastic mulch was sunlight. There was no significant difference in the soil temperature and root water uptake under different treatments. The distribution of soil matrix suction in cotton root zone under plastic mulch was more homogeneous under ' wide and shallow' soil wetting pattern (W633). Under the 'wide and shallow' soil wetting pattern, the average difference of cotton root water consumption between inner row and outer row was 0.67 mm · d(-1), which was favorable to the cotton growing trimly at both inner and outer rows; for the 'narrow and deep' soil wetting pattern (W169), the same index was 0.88 mm · d(-1), which was unfavorable to cotton growing uniformly at both inner and outer rows. So, we should select the broad-shallow type soil wetting pattern in the design of drip irrigation under mulch.

Consequences of waterlogging in cotton and opportunities for mitigation of yield losses

PubMed Central

Najeeb, Ullah; Bange, Michael P.; Tan, Daniel K. Y.; Atwell, Brian J.

2015-01-01

Climatic variability, typified by erratic heavy-rainfall events, causes waterlogging in intensively irrigated crops and is exacerbated under warm temperature regimes on soils with poor internal drainage. Irrigated cotton is often grown in precisely these conditions, exposing it to waterlogging-induced yield losses after substantial summer rainfall. This calls for a deeper understanding of mechanisms of waterlogging tolerance and its relevance to cotton. Hence this review suggests possible causes of waterlogging-induced yield loss in cotton and approaches to improvement of waterlogging tolerance, drawing upon the slight body of published data in cotton and principles from other species. The yield penalty depends on soil type, phenological stage and cumulative period of root exposure to air-filled porosities below 10 %. Events in the soil include O2 deficiency in the root zone that changes the redox state of nutrients, making them unavailable (e.g. nitrogen) or potentially toxic for plants. Furthermore, root-derived hormones that are transported in the xylem have long been associated with oxygen deficits. These belowground effects (impaired root growth, nutrient uptake and transport, hormonal signalling) affect the shoots, interfering with canopy development, photosynthesis and radiation-use efficiency. Compared with the more waterlogging-tolerant cereals, cotton does not have identified adaptations to waterlogging in the root zone, forming no conspicuous root aerenchyma and having low fermentative activity. We speculate that these factors contribute substantially to the sensitivity of cotton to sustained periods of waterlogging. We discuss the impact of these belowground factors on shoot performance, photosynthesis and yield components. Management practices, i.e. soil aeration, scheduling irrigation and fertilizer application, can reduce waterlogging-induced damage. Limiting ethylene biosynthesis using anti-ethylene agents and down-regulating expression of genes controlling ethylene biosynthesis are strong candidates to minimize yield losses in waterlogged cotton crops. Other key pathways of anoxia tolerance are also cited as potential tools towards waterlogging-tolerant cotton genotypes. PMID:26194168

Comparison of Antibacterial Efficacy of Turmeric Extract, Morinda Citrifolia and 3% Sodium Hypochlorite on Enterococcus faecalis: An In-vitro Study.

PubMed

Chaitanya, Bathula Vimala; Somisetty, Kusum Valli; Diwan, Abhinav; Pasha, Shiraz; Shetty, Nandaprasad; Reddy, Yashwanth; Nadigar, Shankar

2016-10-01

Sodium hypochlorite (NaOCl), the most commonly used irrigant, has many potential properties like its unique ability to dissolve pulp tissue, excellent antimicrobial activity, but has a cytotoxic effect when injected into periapical tissues. It is also known to produce allergic reactions, foul smell and taste, and potential for corrosion. Facultative organisms such as Enterococcus faecalis and aerobes like Staphylococcus aureus are considered to be the most resistant species and one of the possible causes of root canal treatment failure. So there is a need to find an alternative to sodium hypochlorite to act against these resistant microorganisms. To evaluate and compare the antibacterial efficacy of morinda citrifolia and turmeric extract with 3% NaOCl as a root canal irrigant, against E. faecalis and S.aureus . The antimicrobial efficacy was assessed in vitro using agar well diffusion method. Agar plates were prepared using Brain-Heart Infusion (BHI) agar. Cultures of E.faecalis and S.aureus were grown in nutrient broth at 37°C. Plates were incubated for 24 hours at 37°C and microbial zones of inhibition were recorded. Statistical analysis was performed using ANOVA. NaOCl (3%) showed larger zones of inhibition than herbal irrigants against both the microorganisms. Among the herbal irrigants, morinda citrifolia showed larger zones of inhibition than turmeric hydro-alcoholic extract and turmeric water extract which was statistically significant (p<0.05). NaOCl (3%) showed maximum antibacterial activity against E. faecalis , followed by morinda citrifolia and turmeric extracts. Considering the potential for undesirable properties of NaOCl, use of herbal alternatives in endodontics might prove to be advantageous.

Comparison of Antibacterial Efficacy of Turmeric Extract, Morinda Citrifolia and 3% Sodium Hypochlorite on Enterococcus faecalis: An In-vitro Study

PubMed Central

Somisetty, Kusum Valli; Diwan, Abhinav; Pasha, Shiraz; Shetty, Nandaprasad; Reddy, Yashwanth; Nadigar, Shankar

2016-01-01

Introduction Sodium hypochlorite (NaOCl), the most commonly used irrigant, has many potential properties like its unique ability to dissolve pulp tissue, excellent antimicrobial activity, but has a cytotoxic effect when injected into periapical tissues. It is also known to produce allergic reactions, foul smell and taste, and potential for corrosion. Facultative organisms such as Enterococcus faecalis and aerobes like Staphylococcus aureus are considered to be the most resistant species and one of the possible causes of root canal treatment failure. So there is a need to find an alternative to sodium hypochlorite to act against these resistant microorganisms. Aim To evaluate and compare the antibacterial efficacy of morinda citrifolia and turmeric extract with 3% NaOCl as a root canal irrigant, against E. faecalis and S.aureus. Materials and Methods The antimicrobial efficacy was assessed in vitro using agar well diffusion method. Agar plates were prepared using Brain-Heart Infusion (BHI) agar. Cultures of E.faecalis and S.aureus were grown in nutrient broth at 37°C. Plates were incubated for 24 hours at 37°C and microbial zones of inhibition were recorded. Statistical analysis was performed using ANOVA. Results NaOCl (3%) showed larger zones of inhibition than herbal irrigants against both the microorganisms. Among the herbal irrigants, morinda citrifolia showed larger zones of inhibition than turmeric hydro-alcoholic extract and turmeric water extract which was statistically significant (p<0.05). Conclusion NaOCl (3%) showed maximum antibacterial activity against E. faecalis, followed by morinda citrifolia and turmeric extracts. Considering the potential for undesirable properties of NaOCl, use of herbal alternatives in endodontics might prove to be advantageous. PMID:27891459

Soil water movement in the unsaturated zone of an inland arid region: Mulched drip irrigation experiment

NASA Astrophysics Data System (ADS)

Han, Dongmei; Zhou, Tiantian

2018-04-01

Agricultural irrigation with trans-basin water diversion can effectively relieve the water paucity in arid and semi-arid regions, however, this may be accompanied by eco-environmental problems (e.g., saline soils, rising groundwater levels, water quality problems). The mechanism of soil water movement under irrigation in the unsaturated zone of arid regions is a key scientific problem that should be solved in order to evaluate agricultural water management and further improve current irrigation practices. This study investigated the impact of drip irrigation on soil water movement in the unsaturated zone of a cotton field in an inland arid region (the Karamay Agricultural Development Area), northwest China. Combining in situ observational physical data with temporal variation in stable isotopic compositions of soil water, we described the soil water flow system and mechanism in severe (Plot 1) and mild (Plot 2) saline-alkali cotton fields. The infiltration depths are 0-150 cm for both plots. Drip irrigation scheduling makes no significant contribution to local groundwater recharge, however, groundwater can move into the unsaturated zone through capillary rise during cotton flowering and boll periods. Plot 2 is less prone to having secondary soil salinization than Plot 1 due to the existence of a middle layer (approximately 100 cm thick), which elongated the distance between the root zone and aquifer. Rise in the water table (approximately 60 cm for Plot 1 and 50 cm for Plot 2) could be caused by lateral groundwater flow instead of vertical infiltration. We estimated the soil water storage changes in the unsaturated zone and proposed a conceptual model for deciphering the movement process of soil water. This study provides a scientific basis for determining the rise of groundwater levels and potential development of saline soils and improving agricultural water management in arid regions.

Matching soil salinization and cropping systems in communally managed irrigation schemes

NASA Astrophysics Data System (ADS)

Malota, Mphatso; Mchenga, Joshua

2018-03-01

Occurrence of soil salinization in irrigation schemes can be a good indicator to introduce high salt tolerant crops in irrigation schemes. This study assessed the level of soil salinization in a communally managed 233 ha Nkhate irrigation scheme in the Lower Shire Valley region of Malawi. Soil samples were collected within the 0-0.4 m soil depth from eight randomly selected irrigation blocks. Irrigation water samples were also collected from five randomly selected locations along the Nkhate River which supplies irrigation water to the scheme. Salinity of both the soil and the irrigation water samples was determined using an electrical conductivity (EC) meter. Analysis of the results indicated that even for very low salinity tolerant crops (ECi < 2 dS/m), the irrigation water was suitable for irrigation purposes. However, root-zone soil salinity profiles depicted that leaching of salts was not adequate and that the leaching requirement for the scheme needs to be relooked and always be adhered to during irrigation operation. The study concluded that the crop system at the scheme needs to be adjusted to match with prevailing soil and irrigation water salinity levels.

The effect of passive ultrasonic activation of 2% chlorhexidine or 5.25% sodium hypochlorite irrigant on residual antimicrobial activity in root canals.

PubMed

Weber, Carol Diener; McClanahan, Scott B; Miller, Glenn A; Diener-West, Marie; Johnson, James D

2003-09-01

Ninety-four single-canal roots were prepared using the step-down technique. Forty-two canals were irrigated with 2% chlorhexidine, 42 canals with 5.25% sodium hypochlorite (NaOCl), and 10 control canals with phosphate-buffered saline (PBS). The chlorhexidine and NaOCl groups were each then equally divided into a final irrigation group and a 1-min passive ultrasonic irrigation group. Canals were enlarged with a Parapost drill. The apical 3-5 mm was covered with nail polish. Canals were rinsed with PBS, dried, refilled with PBS, and stored. At 6 h, 20 microl of fluid was pipetted from each canal and placed into wells on agar plates, which were inoculated with Streptococcus sanguinis. The plates were incubated, and zones of inhibition were measured. Sampling was repeated at 24, 48, 72, 96, 120, 144, and 168 h. Residual antimicrobial activity with 2% chlorhexidine was statistically significantly superior to 5.25% NaOCl with irrigation alone and with final passive ultrasonic activation (p < 0.001). Chlorhexidine experimental groups demonstrated residual antimicrobial activity for as long as 168 h.

Plasticity in stomatal size and density of potato leaves under different irrigation and phosphorus regimes.

PubMed

Sun, Yanqi; Yan, Fei; Cui, Xiaoyong; Liu, Fulai

2014-09-01

The morphological features of stomata including their size and density could be modulated by environmental cues; however, the underlying mechanisms remain largely elusive. Here, the effect of different irrigation and phosphorus (P) regimes on stomatal size (SS) and stomatal density (SD) of potato leaves was investigated. The plants were grown in split-root pots under two P fertilization rates (viz., 0 and 100mgkg(-1) soil, denoted as P0 and P1, respectively) and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation regimes. Results showed that SS and SD were unresponsive to P but significantly affected by the irrigation treatment. FI plants had the largest SS, followed by DI, and PRD the smallest; and the reverse was the case for SD. Compared to FI and DI, PRD plants had significantly lower values of specific leaf area (SLA) and leaf carbon isotope discrimination (Δ(13)C) under P0. Midday leaf water potential (Ψleaf) and stomatal conductance (gs) was similar for DI and PRD, which was significantly lower than that of FI. Leaf contents of C, N, K, Ca and Mg were higher in PRD than in DI plants, particularly under P0. When analyzed across the three irrigation regimes, it was found that the P1 plants had significantly higher leaf contents of P and Mg, but significantly lower leaf K content compared to the P0 plants. Linear correlation analyses revealed that SS was positively correlated with Ψleaf and Δ(13)C; whereas SD was negatively correlated with Ψleaf, Δ(13)C and SLA, and positively correlated with leaf C, N and Ca contents. And gs was positively correlated with SS but negatively correlated with SD. Collectively, under low P level, the smaller and denser stomata in PRD plants may bring about a more efficient stomatal control over gas exchange, hereby potentially enhance water-use efficiency as exemplified by the lowered leaf Δ(13)C under fluctuating soil moisture conditions. Copyright © 2014 Elsevier GmbH. All rights reserved.

Moving forward on remote sensing of soil salinity at regional scale

USDA-ARS?s Scientific Manuscript database

Soil salinity undermines global agriculture by reducing crop yield and soil quality. Irrigation management can help control salinity levels within the root-zone. To best allocate water resources, accurate regional-scale inventories are needed. Two remote sensing approaches are currently used to moni...

Is irrigation with partial desalinated seawater a policy option for saving freshwater in the Kingdom of Saudi Arabia

NASA Astrophysics Data System (ADS)

Multsch, Sebastian; Alquwaizany, Abdulaziz S.; Lehnert, Karl-H.; Frede, Hans-Georg; Breuer, Lutz

2015-04-01

The agriculture sector consumes with 88 % a majority of the almost fossil water resources in the Kingdom of Saudi Arabia (KSA). Irrigation with saline water has been highlighted to be a promising technique to reduce fresh water consumption. Current desalination techniques, further developments, salt tolerant crop types and improved irrigation systems can potentially redesign future perspectives for irrigation agriculture, in particular by considering the growing desalination capacity in KSA (5 million m3 day-1 in 2003). Hence, we have analyzed the potential of using desalinated and partial desalinated seawater for growing crops in KSA by considering scenarios of salinity levels and desalination costs. The desalination process has been modelled with the ROSA© software considering a reverse osmosis (RO) plant. The spatial decision support system SPARE:WATER has been applied to assess the water footprint of crops (WFcrop). In order to maintain high crop yields, salts need to be washed out from the rooting zone, which requires the application of additional salt-free water. Therefore, high crop yields come along with additional water requirements and increased desalination effort and increased costs for proving high quality water. As an example, growing wheat with partial desalinated seawater from the Arabian Gulf with a RO plant has been investigated. Desalination reduces the salinity level from 76 dS m-1 to 0.5 dS m-1 considering two RO cycles, with cost of desalinized water in the range of 0.5 to 1.2 m-3. We acknowledge that cost only refer to desalination without considering others such as transport, water pumping or crop fertilization. The study shows that Boron is the most problematic salt component, because it is difficult to remove by RO and toxic in high concentrations for crops (wheat threshold of 0.5 to 1.0 mg l-1). The nationwide average WFcrop of wheat under surface irrigation is 2,628 m3 t-1 considering high water quality of 1 dS m-1 and 3,801 m3 t-1 at 12 dS m-1. Using sprinkler or drip irrigation systems the WFcrop decreases of about 20 % and 34 %, respectively. It can be shown that a salinity level larger than 9 dS m-1 increases leaching water requirement of wheat over proportional and that a salinity level of 9 dS m-1 reduces cost for irrigation water by about 11 % in comparison to the irrigation with nearly fresh water quality of 1 dS m-1. A trade-off analyses reveals that making desalinated seawater use profitable, cost need to be reduced below 0.2 m-3 for sprinkler and drip irrigation and even below 0.1 m-3 for widespread used surface irrigation systems. The authors gratefully acknowledge the support of the King Abdulaziz City for Science and Technology (KACST), Saudi Arabia, for funding the research Project No. 33-900 entitled 'Technology for desalinated seawater use in agriculture'.

Root Induced Heterogeneity In Agricultural Soils

NASA Astrophysics Data System (ADS)

Gomes, C.; Gabai, R.; Weisbrod, N.; Furman, A.

2012-12-01

In this study we investigate the role of plant induced heterogeneity on water dynamics in agricultural soils. We conducted three experiments in two sites (one still ongoing) in which a trench was excavated in the root zone of an orchard and the subsurface, to a depth of over 1 m, was instrumented in high resolution with water content, water potential and temperature sensors. High temporal resolution monitoring of soil state was carried for over a year, period that included natural (Mediterranean) climate boundary forcing. In addition, sprinkler, flood, and spray irrigation boundary conditions were forced for short time periods to explore the infiltration process under these conditions. One site was an Avocado orchard planted in red sandy soil while the other, still on-going, is in a grape vineyards irrigated by tap and treated wastewater, planted over alluvial clayey soil. In the vineyard, we are comparing soil irrigated with fresh water to soil irrigated with treated waste water for more than 10 years. Our preliminary results indicate several interesting phenomena. First, the role of plant roots is clearly seen as the major roots act as a conduit for water (and solute), providing a fast bypass of the upper soil. Further, we identified different regions of the subsurface that apparently were of the same texture, but in practice presented very different hydraulic properties. Second, the role of these roots depends on the boundary conditions. That is, the root bypass acts differently when soil is flooded than when flow is strictly unsaturated. As expected, simulation of the experimental results show good fit only if the domain heterogeneity of soil properties was incorporated. Results for the clayey soils were not available at time of abstract submission.

Effects of shallow water table, salinity and frequency of irrigation water on the date palm water use

NASA Astrophysics Data System (ADS)

Askri, Brahim; Ahmed, Abdelkader T.; Abichou, Tarek; Bouhlila, Rachida

2014-05-01

In southern Tunisia oases, waterlogging, salinity, and water shortage represent serious threats to the sustainability of irrigated agriculture. Understanding the interaction between these problems and their effects on root water uptake is fundamental for suggesting possible options of improving land and water productivity. In this study, HYDRUS-1D model was used in a plot of farmland located in the Fatnassa oasis to investigate the effects of waterlogging, salinity, and water shortage on the date palm water use. The model was calibrated and validated using experimental data of sap flow density of a date palm, soil hydraulic properties, water table depth, and amount of irrigation water. The comparison between predicted and observed data for date palm transpiration rates was acceptable indicating that the model could well estimate water consumption of this tree crop. Scenario simulations were performed with different water table depths, and salinities and frequencies of irrigation water. The results show that the impacts of water table depth and irrigation frequency vary according to the season. In summer, high irrigation frequency and shallow groundwater are needed to maintain high water content and low salinity of the root-zone and therefore to increase the date palm transpiration rates. However, these factors have no significant effect in winter. The results also reveal that irrigation water salinity has no significant effect under shallow saline groundwater.

Analysis and comparison of modern methods of turf irrigation, verifying the capability of existing information systems through the use of numerical modeling

NASA Astrophysics Data System (ADS)

Deangelis, Maria Laura; Facoetti, Nicola

2016-04-01

The automated irrigation of parks and gardens in public areas has become more and more a common practice due to the many benefits it brings in terms of improving the quality of urban green areas. Since this practice requires significant volumes of water, and this becomes increasingly scarce and expensive, it is necessary that the design criteria and use management aim at maximizing the irrigation efficiency. There are conflicting relationship and competition between trees and turf for several reasons. On one hand the different irrigation needs can cause excess water in the root zones of the trees, on the other hand the surface roots of trees and the shade created from the leaves by the dripline (projection line of the canopy) determine an unfavorable area to the growth of the turf because of light factor. It follows that for an optimal design of an irrigation system is necessary to separate the turf areas from trees, with the disadvantage of considerably complicate the geometries of the sprinklers. Each tree or group of trees need to be associated to a not irrigated area. This problem seems not to have a specifically bibliographical evidence, although there are operating standards primarily used to define buffer zones for trees from constructions (British Standard 5837:2005). Ideally, a high number of sprinklers is required to follow the shape of the areas perfectly. Hence, an additional step is necessary to simplify these geometries, identifying a correct scheme for the sprinkler spacing. Such a sequence of geometric operations has been tested on the "Indro Montanelli" park in Milan, obtaining a reduction of the irrigated area of 47% and a water saving of around 30%. We intend to continue the research applying the model to other parks, verifying its applicability in different situations.

Wireless lysimeters for real-time online soil water monitoring

USDA-ARS?s Scientific Manuscript database

Identification of nitrate-nitrogen (NO3-N) in drainage water allows accessing the effectiveness of water quality management. A passive capillary wick-type lysimeter (PCAPs) was used to monitor water flux and NO3-N leached below the root zone under an irrigated cropping system. Wireless lysimeters we...

Precipitation, irrigation and crop growth signals in COSMOS data

USDA-ARS?s Scientific Manuscript database

Soil water sensors are used to characterize water content in the root zone and below for water management and environmental monitoring, but only a few are capable of sensing soil volumes larger than a few hundred liters. Scientists with the USDA-ARS Conservation & Production Research Laboratory, Bus...

The efficiency of different irrigation solutions and techniques for the removal of triple antibiotic paste from simulated immature root canals.

PubMed

Ustun, Y; Düzgün, S; Aslan, T; Aktı, A

2018-03-01

The purpose of this study was to evaluate the efficiencies of different irrigation protocols in the removal of triple antibiotic paste (TAP) from root canals. A total of 127 extracted human maxillary incisor teeth were prepared. Then, root-end resection of 3 mm was accomplished to simulate immature apex model. The root canals were filled with TAP, after 21 days, randomly divided into nine groups according to irrigation systems and solutions (n = 13). Conventional irrigation (CI) groups - Group 1: Root canal irrigation was performed with CI by Peracetic acid (PAA) solution, Group 2: Root canal irrigation was performed with CI by etidronic acid 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) + sodium hypochlorite (NaOCl) solution, Group 3: Root canal irrigation was performed with CI by ethylenediaminetetraacetic acid (EDTA)/NaOCl solutions. Vibringe system groups - Group 4: Root canal irrigation was performed with Vibringe system by PAA solution, Group 5: Root canal irrigation was performed with Vibringe system by HEBP + NaOCl solution, Group 6: Root canal irrigation was performed with Vibringe system by EDTA/NaOCl solution. EndoVac system groups - Group 7: Root canal irrigation was performed with EndoVac system by PAA solution, Group 8: Root canal irrigation was performed with EndoVac system by HEBP + NaOCl solution, Group 9: Root canal irrigation was performed with EndoVac system by EDTA/NaOCl solution. Control Group: (n = 0). Samples were sectioned vertically, and the amount of remaining medicament was scored for each root half and data were statistically analyzed. Among the irrigation systems, CI groups showed the highest scores at both apical and coronal parts (P < 0.05). In comparisons among the solutions, at the apical part, PAA groups showed the highest scores (P < 0.05). At the coronal part, EDTA + NaOCl groups showed the lowest score values (P < 0.05). The use of irrigation systems improved the removal of TAP from the simulated immature root canals. Also, as an irrigation solution EDTA gives more promising results than PAA and HEBP solutions.

Sap fluxes from different parts of the rootzone modulate xylem ABA concentration during partial rootzone drying and re-wetting

PubMed Central

Pérez-Pérez, J. G.; Dodd, I. C.

2015-01-01

Previous studies with partial rootzone drying (PRD) irrigation demonstrated that alternating the wet and dry parts of the rootzone (PRD-Alternated) increased leaf xylem ABA concentration ([X-ABA]leaf) compared with maintaining the same wet and dry parts of the rootzone (PRD-Fixed). To determine the relative contributions of different parts of the rootzone to this ABA signal, [X-ABA]leaf of potted, split-root tomato (Solanum lycopersicum) plants was modelled by quantifying the proportional water uptake from different soil compartments, and [X-ABA]leaf responses to the entire pot soil-water content (θpot). Continuously measuring soil-moisture depletion by, or sap fluxes from, different parts of the root system revealed that water uptake rapidly declined (within hours) after withholding water from part of the rootzone, but was rapidly restored (within minutes) upon re-watering. Two hours after re-watering part of the rootzone, [X-ABA]leaf was equally well predicted according to θpot alone and by accounting for the proportional water uptake from different parts of the rootzone. Six hours after re-watering part of the rootzone, water uptake by roots in drying soil was minimal and, instead, occurred mainly from the newly irrigated part of the rootzone, thus [X-ABA]leaf was best predicted by accounting for the proportional water uptake from different parts of the rootzone. Contrary to previous results, alternating the wet and dry parts of the rootzone did not enhance [X-ABA]leaf compared with PRD-Fixed irrigation. Further work is required to establish whether altered root-to-shoot ABA signalling contributes to the improved yields of crops grown with alternate, rather than fixed, PRD. PMID:25740924

Sap fluxes from different parts of the rootzone modulate xylem ABA concentration during partial rootzone drying and re-wetting.

PubMed

Pérez-Pérez, J G; Dodd, I C

2015-04-01

Previous studies with partial rootzone drying (PRD) irrigation demonstrated that alternating the wet and dry parts of the rootzone (PRD-Alternated) increased leaf xylem ABA concentration ([X-ABA]leaf) compared with maintaining the same wet and dry parts of the rootzone (PRD-Fixed). To determine the relative contributions of different parts of the rootzone to this ABA signal, [X-ABA]leaf of potted, split-root tomato (Solanum lycopersicum) plants was modelled by quantifying the proportional water uptake from different soil compartments, and [X-ABA]leaf responses to the entire pot soil-water content (θpot). Continuously measuring soil-moisture depletion by, or sap fluxes from, different parts of the root system revealed that water uptake rapidly declined (within hours) after withholding water from part of the rootzone, but was rapidly restored (within minutes) upon re-watering. Two hours after re-watering part of the rootzone, [X-ABA]leaf was equally well predicted according to θpot alone and by accounting for the proportional water uptake from different parts of the rootzone. Six hours after re-watering part of the rootzone, water uptake by roots in drying soil was minimal and, instead, occurred mainly from the newly irrigated part of the rootzone, thus [X-ABA]leaf was best predicted by accounting for the proportional water uptake from different parts of the rootzone. Contrary to previous results, alternating the wet and dry parts of the rootzone did not enhance [X-ABA]leaf compared with PRD-Fixed irrigation. Further work is required to establish whether altered root-to-shoot ABA signalling contributes to the improved yields of crops grown with alternate, rather than fixed, PRD. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Evaluation of Three Models for Simulating Pesticide Runoff from Irrigated Agricultural Fields.

PubMed

Zhang, Xuyang; Goh, Kean S

2015-11-01

Three models were evaluated for their accuracy in simulating pesticide runoff at the edge of agricultural fields: Pesticide Root Zone Model (PRZM), Root Zone Water Quality Model (RZWQM), and OpusCZ. Modeling results on runoff volume, sediment erosion, and pesticide loss were compared with measurements taken from field studies. Models were also compared on their theoretical foundations and ease of use. For runoff events generated by sprinkler irrigation and rainfall, all models performed equally well with small errors in simulating water, sediment, and pesticide runoff. The mean absolute percentage errors (MAPEs) were between 3 and 161%. For flood irrigation, OpusCZ simulated runoff and pesticide mass with the highest accuracy, followed by RZWQM and PRZM, likely owning to its unique hydrological algorithm for runoff simulations during flood irrigation. Simulation results from cold model runs by OpusCZ and RZWQM using measured values for model inputs matched closely to the observed values. The MAPE ranged from 28 to 384 and 42 to 168% for OpusCZ and RZWQM, respectively. These satisfactory model outputs showed the models' abilities in mimicking reality. Theoretical evaluations indicated that OpusCZ and RZWQM use mechanistic approaches for hydrology simulation, output data on a subdaily time-step, and were able to simulate management practices and subsurface flow via tile drainage. In contrast, PRZM operates at daily time-step and simulates surface runoff using the USDA Soil Conservation Service's curve number method. Among the three models, OpusCZ and RZWQM were suitable for simulating pesticide runoff in semiarid areas where agriculture is heavily dependent on irrigation. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Farm water budgets for semiarid irrigated floodplains of northern New Mexico: characterizing the surface water-groundwater interactions

NASA Astrophysics Data System (ADS)

Gutierrez, K. Y.; Fernald, A.; Ochoa, C. G.; Guldan, S. J.

2013-12-01

KEY WORDS - Hydrology, Water budget, Deep percolation, Surface water-Groundwater interactions. With the recent projections for water scarcity, water balances have become an indispensable water management tool. In irrigated floodplains, deep percolation from irrigation can represent one of the main aquifer recharge sources. A better understanding of surface water and groundwater interactions in irrigated valleys is needed for properly assessing the water balances in these systems and estimating potential aquifer recharge. We conducted a study to quantify the parameters and calculate the water budgets in three flood irrigated hay fields with relatively low, intermediate and, high water availability in northern New Mexico. We monitored different hydrologic parameters including total amount of water applied, change in soil moisture, drainage below the effective root zone, and shallow water level fluctuations in response to irrigation. Evapotranspiration was calculated from weather station data collected in-situ using the Samani-Hargreaves. Previous studies in the region have estimated deep percolation as a residual parameter of the water balance equation. In this study, we used both, the water balance method and actual measurements of deep percolation using passive lysimeters. Preliminary analyses for the three fields show a relatively rapid movement of water through the upper 50 cm of the vadose zone and a quick response of the shallow aquifer under flood irrigation. Further results from this study will provide a better understanding of surface water-groundwater interactions in flood irrigated valleys in northern New Mexico.

COSMOS soil water sensor compared with EM sensor network & weighing lysimeter

USDA-ARS?s Scientific Manuscript database

Soil water sensing methods are widely used to characterize the root zone and below, but only a few are capable of delivering water content data with accuracy for the entire soil profile such that evapotranspiration (ET) can be determined by soil water balance and irrigations can be scheduled with mi...

Impact of phenazine-producing pseudomonads upon Fe and Mn bioavailability in the rhizosphere of dryland wheat

USDA-ARS?s Scientific Manuscript database

Large populations of plant-growth-promoting Pseudomonas fluorescens strains producing up to 1 µg/g root of the redox-active antibiotic phenazine-1-carboxylic acid (PCA) have been discovered in dryland but not irrigated wheat fields throughout the low precipitation zone of the Columbia Plateau of the...

Crop model application to soybean irrigation management in the mid-south USA

USDA-ARS?s Scientific Manuscript database

Since mid 1990s, there have been a rapid development and application of crop growth models such as APEX (the Agricultural Policy/Environmental eXtender) and RZWQM2 (Root Zone Water Quality Model). Such process-oriented models have been designed to study the interactions of genetypes, weather, soil, ...

Potassium fertigation in highbush blueberry increases availability of K and other nutrients in the root zone

USDA-ARS?s Scientific Manuscript database

Fertigation with nitrogen (N) increases growth and production relative to granular N applications in blueberry, but little information is available on whether there is any benefit to fertigating with other nutrients. The plants were grown on raised beds and irrigated using two lines of drip tubing p...

Modeling yield and biomass responses of maize cultivars to climate change under full and deficit irrigation

USDA-ARS?s Scientific Manuscript database

As climate change becomes inevitable, the agricultural community is concerned about its possible effects on crop production and developing strategies to adapt to this change. In this study, the Root Zone Water Quality Model (RZWQM2) was calibrated with four years of maize data from central Colorado ...

Root canal irrigants

PubMed Central

Kandaswamy, Deivanayagam; Venkateshbabu, Nagendrababu

2010-01-01

Successful root canal therapy relies on the combination of proper instrumentation, irrigation, and obturation of the root canal. Of these three essential steps of root canal therapy, irrigation of the root canal is the most important determinant in the healing of the periapical tissues. The primary endodontic treatment goal must thus be to optimize root canal disinfection and to prevent reinfection. In this review of the literature, various irrigants and the interactions between irrigants are discussed. We performed a Medline search for English-language papers published untill July 2010. The keywords used were ‘root canal irrigants’ and ‘endodontic irrigants.’ The reference lists of each article were manually checked for additional articles of relevance. PMID:21217955

Adopting adequate leaching requirement for practical response models of basil to salinity

NASA Astrophysics Data System (ADS)

Babazadeh, Hossein; Tabrizi, Mahdi Sarai; Darvishi, Hossein Hassanpour

2016-07-01

Several mathematical models are being used for assessing plant response to salinity of the root zone. Objectives of this study included quantifying the yield salinity threshold value of basil plants to irrigation water salinity and investigating the possibilities of using irrigation water salinity instead of saturated extract salinity in the available mathematical models for estimating yield. To achieve the above objectives, an extensive greenhouse experiment was conducted with 13 irrigation water salinity levels, namely 1.175 dS m-1 (control treatment) and 1.8 to 10 dS m-1. The result indicated that, among these models, the modified discount model (one of the most famous root water uptake model which is based on statistics) produced more accurate results in simulating the basil yield reduction function using irrigation water salinities. Overall the statistical model of Steppuhn et al. on the modified discount model and the math-empirical model of van Genuchten and Hoffman provided the best results. In general, all of the statistical models produced very similar results and their results were better than math-empirical models. It was also concluded that if enough leaching was present, there was no significant difference between the soil salinity saturated extract models and the models using irrigation water salinity.

Coordinating management of water, salinity and trace elements for cotton under mulched drip irrigation with brackish water

NASA Astrophysics Data System (ADS)

Jin, M.; Chen, W.; Liang, X.

2016-12-01

Rational irrigation with brackish water can increase crop production, but irrational use may cause soil salinization. In order to understand the relationships among water, salt, and nutrient (including trace elements) and find rational schemes to manage water, salinity and nutrient in cotton fields, field and pot experiments were conducted in an arid area of southern Xinjiang, northwest China. Field experiments were performed from 2008 to 2015, and involved mulched drip irrigation during the growing season and flood irrigation afterwards. The average cotton yield of seven years varied between 3,575 and 5,095 kg/ha, and the irrigation water productivity between 0.91 and 1.16 kg/m3. With the progress of brackish water irrigation, Cu, Fe, Mn, and Na showed strong aggregation in topsoil at the narrow row, whereas the contents of Ca and K decreased in the order of inter-mulch gap, the wide inter row, and the narrow row. The contents of Cu, Fe, Mn, Ca and K in root soil reduced with cotton growth, whereas Na increased. Although mulched drip irrigation during the growing season resulted in an increase in salinity in the root zone, flood irrigation after harvesting leached the accumulated salts below background levels. Based on experiments a scheme for coordinating management of soil water, salt, and nutrient is proposed, that is, under the planting pattern of one mulch, two drip lines and four rows, the alternative irrigation plus a flood irrigation after harvesting or before seeding was the ideal scheme. Numerical simulations using solute transport model coupled with the root solute uptake based on the experiments and extended by another 20 years, suggest that the mulched drip irrigation using alternatively fresh and brackish water during the growing season and flood irrigation with fresh water after harvesting, is a sustainable irrigation practice that should not lead to soil salinization. Pot experiments with trace elements and different saline water showed significantly antagonistic effects on cotton growth and yield between NaCl and Mn or Zn or B. Zn concentration in irrigation water under salinity stress affected the uptake of nutrient elements and caused the different contents of nutrient elements in cotton, and influenced cotton growth and yields.

Spectrophotometric determination of irrigant extrusion using passive ultrasonic irrigation, EndoActivator, or syringe irrigation.

PubMed

Rodríguez-Figueroa, Carolina; McClanahan, Scott B; Bowles, Walter R

2014-10-01

Sodium hypochlorite (NaOCl) irrigation is critical to endodontic success, and several new methods have been developed to improve irrigation efficacy (eg, passive ultrasonic irrigation [PUI] and EndoActivator [EA]). Using a novel spectrophotometric method, this study evaluated NaOCl irrigant extrusion during canal irrigation. One hundred fourteen single-rooted extracted teeth were decoronated to leave 15 mm of the root length for each tooth. Cleaning and shaping of the teeth were completed using standardized hand and rotary instrumentation to an apical file size #40/0.04 taper. Roots were sealed (not apex), and 54 straight roots (n = 18/group) and 60 curved roots (>20° curvature, n = 20/group) were included. Teeth were irrigated with 5.25% NaOCl by 1 of 3 methods: passive irrigation with needle, PUI, or EA irrigation. Extrusion of NaOCl was evaluated using a pH indicator and a spectrophotometer. Standard curves were prepared with known amounts of irrigant to quantify amounts in unknown samples. Irrigant extrusion was minimal with all methods, with most teeth showing no NaOCl extrusion in straight or curved roots. Minor NaOCl extrusion (1-3 μL) in straight roots or curved roots occurred in 10%-11% of teeth in all 3 irrigant methods. Two teeth in both the syringe irrigation and the EA group extruded 3-10 μL of NaOCl. The spectrophotometric method used in this study proved to be very sensitive while providing quantification of the irrigant levels extruded. Using the PUI or EA tip to within 1 mm of the working length appears to be fairly safe, but apical anatomy can vary in teeth to allow extrusion of irrigant. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Influence of Laser Activated Irrigation with two Erbium Lasers on Bond Strength of Inidividually Formed Fiber Reinforced Composite Posts to Root Canal Dentin.

PubMed

Parčina, Ivana; Amižić; Miletić, Ivana; Ionescu, Andrei C; Brambilla, Eugenio; Gabrić, Dragana; Baraba, Anja

2016-12-01

The aim of this in vitro study was to investigate the effect of laser activated irrigation (LAI) using two erbium lasers on bond strength of individually formed fiber-reinforced composite (FRC) posts to root canal dentin. Twenty-seven single-rooted human teeth were endodontically treated and after post space preparation divided into three groups (n=9 per group), according to the pre-treatment of post space preparation: 1) Conventional syringe irrigation (CSI) and saline; 2) Er.YAG photon-induced photoacoustic streaming (PIPS) technique and saline; 3) Er,Cr:YSGG activated irrigation with RFT2 tip. Two specimens from each group were used for SEM analysis. The remaining specimens (n=7 per group) received individually formed FRC post, everStick POST, luted with self-adhesive cement, G-CEM LinkAce. After cementation, the roots were perpendicularly sectioned into 1 mm thin sections and a push-out test was carried out (0.5 mm/min). The data were calculated as megapascals and were log transformed and statistically analysed using one-way ANOVA at the level of significance set at 5%. In the control group, the smear layer was still present. In the Er:YAG group, the smear layer was removed. In the Er,Cr:YSGG group, the smear layer was partially removed. The Er,Cr:YSGG group achieved the highest bond strength values, followed by the control group and then the Er:YAG group, but no statistically significant difference was found in bond strength values in the tested group of post space pretreatment (p=0.564). LAI using two erbium lasers, with PIPS or RFT2 tip, did not affect the bond strength of individually formed FRC posts to root canal dentin.

Effect of irrigation techniques and strategies on water footprint of growing crops

NASA Astrophysics Data System (ADS)

Chukalla, A. D.; Krol, M. S.; Hoekstra, A. Y. Y.

2014-12-01

Reducing the water footprint (WF) of growing crops, the largest water user and a significant contributor to the WF of many consumer products, plays a significant role in integrated and sustainable water management. The water footprint for growing crop is accounted by relating the crop yield with the corresponding consumptive water use (CWU), which both can be adjusted by measures that affect the crop growth and root-zone soil water balance. This study explored the scope for reducing the water footprint of irrigated crops by experimenting set of field level technical and managerial measures: (i) irrigation technologies (Furrow, sprinkler, drip and sub-surface drip), (ii) irrigation strategies (full and a range of sustained and controlled deficit) and (iii) field management options (zero, organic and synthetic mulching). Ranges of cases were also considered: (a) Arid and semi-arid environment (b) Loam and Sandy-loam soil types and (c) for Potato, Wheat and Maize crops; under (c) wet, normal and dry years. AquaCrop, the water driven crop growth and soil water balance model, offered the opportunity to systematically experiment these measures on water consumption and yield. Further, the green and blue water footprints of growing crop corresponding to each measure were computed by separating the root zone fluxes of the AquaCrop output into the green and blue soil water stocks and their corresponding fluxes. Results showed that in arid environment reduction in irrigation supply, CWU and WF up to 300 mm, 80 mm and 75 m3/tonne respectively can be achieved for Maize by a combination of organic mulching and drip technology with controlled deficit irrigation strategies (10-20-30-40% deficit with reference to the full irrigation requirement). These reductions come with a yield drop of 0.54 tonne/ha. In the same environment under the absence of mulching practice, the sub-surface drip perform better in reducing CWU and WF of irrigated crops followed by drip and furrow irrigation technique. This rank though changes in non-moisture limiting condition (wet year) drip performing better in reducing the WF of growing crops than sub-surface drip. It was observed that with all range of irrigation techniques, strategies and field management practices there is more room in reducing the WF of growing crops in loam than sandy-loam soil.

One step pulp revascularization treatment of an immature permanent tooth with chronic apical abscess: a case report.

PubMed

Shin, S Y; Albert, J S; Mortman, R E

2009-12-01

To describe a case in which a mandibular right second premolar with a necrotic pulp, sinus tract, periradicular radiolucency and an immature apex underwent revascularization via a single treatment approach. Revascularization procedures have the potential to heal a partially necrotic pulp, which can be beneficial for the continued root development of immature teeth. However, it is not clear which revascularization protocols are the most effective. This case report details the outcome of a successful revascularization procedure on tooth 45 (FDI) in a 12-year-old patient, eliminating the associated periapical pathosis within 19 months. The tooth was treated using coronal root irrigation with 6% NaOCl and 2% chlorhexidine without instrumentation in a single visit. The successful outcome of this case report suggests that this conservative revascularization treatment approach can preserve the vitality of the dental pulp stem cells and create a suitable environment for pulp regeneration, resulting in the completion of root maturation. The noninstrumentation procedure using 6% NaOCl and 2% chlorhexidine coronal irrigation may help preserve the remaining vital dental pulp stem cells believed to be critical for pulp revascularization. A single visit pulp revascularization protocol can be a favourable treatment option for an immature permanent tooth with a partially necrotic pulp.

Physiological and gene expression responses of sunflower (Helianthus annuus L.) plants differ according to irrigation placement.

PubMed

Aguado, Ana; Capote, Nieves; Romero, Fernando; Dodd, Ian C; Colmenero-Flores, José M

2014-10-01

To investigate effects of soil moisture heterogeneity on plant physiology and gene expression in roots and leaves, three treatments were implemented in sunflower plants growing with roots split between two compartments: a control (C) treatment supplying 100% of plant evapotranspiration, and two treatments receiving 50% of plant evapotranspiration, either evenly distributed to both compartments (deficit irrigation - DI) or unevenly distributed to ensure distinct wet and dry compartments (partial rootzone drying - PRD). Plants receiving the same amount of water responded differently under the two irrigation systems. After 3 days, evapotranspiration was similar in C and DI, but 20% less in PRD, concomitant with decreased leaf water potential (Ψleaf) and increased leaf xylem ABA concentration. Six water-stress responsive genes were highly induced in roots growing in the drying soil compartment of PRD plants, and their expression was best correlated with local soil water content. On the other hand, foliar gene expression differed significantly from that of the root and correlated better with xylem ABA concentration and Ψleaf. While the PRD irrigation strategy triggered stronger physiological and molecular responses, suggesting a more intense and systemic stress reaction due to local dehydration of the dry compartment of PRD plants, the DI strategy resulted in similar water savings without strongly inducing these responses. Correlating physiological and molecular responses in PRD/DI plants may provide insights into the severity and location of water deficits and may enable a better understanding of long-distance signalling mechanisms. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Effect of Er:YAG laser-activated irrigation solution on Enterococcus Faecalis biofilm in an ex-vivo root canal model.

PubMed

Sahar-Helft, Sharonit; Stabholtz, Adam; Moshonov, Joshua; Gutkin, Vitaly; Redenski, Idan; Steinberg, Doron

2013-07-01

Abstract Objective: The purpose of this study was to evaluate mineral content and surface morphology of root canals coated with Enterococcus faecalis biofilm after treatment with several endodontic irrigation solutions, with and without Er:YAG laser-activated irrigation (LAI). LAI has been introduced as a powerful method for root canal irrigation resulting in smear-layer removal from the root canal wall. Distal and palatal roots from 60 freshly extracted human molars were used in this study. The coronal of each tooth was removed. Roots were split longitudinally and placed in an ultrasonic bath to remove the smear layer, creating conditions for the formation of E. faecalis biofilm. After incubation, the two halves were reassembled in impression material to simulate clinical conditions. Specimens were divided into two main groups: roots rinsed with irrigation solutions and roots subjected to laser irradiation combined with irrigation solutions. Solutions tested were 2% chlorhexidine and 17% ethylenediaminetetraacetic acid (EDTA) and saline. Surface morphology: 17% EDTA irrigant solution combined with Er:YAG laser showed the best results for removing bacteria from the root canal walls. Chemical analysis: all samples treated with combined laser irradiation and irrigation solution had low surface levels of Ca compared with samples treated with irrigation alone. The Ca/P ratio was highest in the laser-EDTA group. Overall, mineral changes caused by laser with irrigation solutions were minimal, and statistically nonsignificant. In vitro irrigation solutions, combined with Er:YAG laser irradiation, were effective in removing E. faecalis biofilm from root canal walls. Irrigation solutions without laser irradiation were less effective, leaving a layer of biofilm on the dentin surface.

Cokriging of Electromagnetic Induction Soil Electrical Conductivity Measurements and Soil Textural Properties to Demarcate Sub-field Management Zones for Precision Irrigation.

NASA Astrophysics Data System (ADS)

Ding, R.; Cruz, L.; Whitney, J.; Telenko, D.; Oware, E. K.

2017-12-01

There is the growing need for the development of efficient irrigation management practices due to increasing irrigation water scarcity as a result of growing population and changing climate. Soil texture primarily controls the water-holding capacity of soils, which determines the amount of irrigation water that will be available to the plant. However, while there are significant variabilities in the textural properties of the soil across a field, conventional irrigation practices ignore the underlying variability in the soil properties, resulting in over- or under-irrigation. Over-irrigation leaches plant nutrients beyond the root-zone leading to fertilizer, energy, and water wastages with dire environmental consequences. Under-irrigation, in contrast, causes water stress of the plant, thereby reducing plant quality and yield. The goal of this project is to leverage soil textural map of a field to create water management zones (MZs) to guide site-specific precision irrigation. There is increasing application of electromagnetic induction methods to rapidly and inexpensively map spatially continuous soil properties in terms of the apparent electrical conductivity (ECa) of the soil. ECa is a measure of the bulk soil properties, including soil texture, moisture, salinity, and cation exchange capacity, making an ECa map a pseudo-soil map. Data for the project were collected from a farm site at Eden, NY. The objective is to leverage high-resolution ECa map to predict spatially dense soil textural properties from limited measurements of soil texture. Thus, after performing ECa mapping, we conducted particle-size analysis of soil samples to determine the textural properties of soils at selected locations across the field. We cokriged the high-resolution ECa measurements with the sparse soil textural data to estimate a soil texture map for the field. We conducted irrigation experiments at selected locations to calibrate representative water-holding capacities of each estimated soil textural unit. Estimated soil units with similar water-holding characteristics were merged to create sub-field water MZs to guide precision irrigation of each MZ, instructed by each MZ's calibrated water-holding properties.

In situ sensors, weighing lysimeters and COSMOS under vegetated and bare conditions with subsurface drip irrigation

USDA-ARS?s Scientific Manuscript database

Long term weighing lysimeter records may have utility for assessment of climate changes occurring during the period of record. They typically enclose a depth of soil that exceeds the root zone of vegetation normally grown on them and have drainagy systems so that more or less natural hydrologic flux...

Adaptation of fine roots to annual fertilization and irrigation in a 13-year-old Pinus pinaster stand.

PubMed

Bakker, M R; Jolicoeur, E; Trichet, P; Augusto, L; Plassard, C; Guinberteau, J; Loustau, D

2009-02-01

Effects of fertilization and irrigation on fine roots and fungal hyphae were studied in 13-year-old maritime pine (Pinus pinaster Aït. in Soland), 7 years after the initiation of the treatments. The fertilization trials consisted of a phosphorus treatment, a complete fertilizer treatment (N, P, K, Ca and Mg), and an unfertilized treatment (control). Fertilizers were applied annually and were adjusted according to foliar target values. Two irrigation regimes (no irrigation and irrigation of a set amount each day) were applied from May to October. Root samples to depths of 120 cm were collected in summer of 2005, and the biomass of small roots (diameter 2-20 mm) and fine roots (diameter

Assessment of solute fluxes beneath an orchard irrigated with treated sewage water: A numerical study

NASA Astrophysics Data System (ADS)

Russo, David; Laufer, Asher; Shapira, Roi H.; Kurtzman, Daniel

2013-02-01

Detailed numerical simulations were used to analyze water flow and transport of nitrate, chloride, and a tracer solute in a 3-D, spatially heterogeneous, variably saturated soil, originating from a citrus orchard irrigated with treated sewage water (TSW) considering realistic features of the soil-water-plant-atmosphere system. Results of this study suggest that under long-term irrigation with TSW, because of nitrate uptake by the tree roots and nitrogen transformations, the vadose zone may provide more capacity for the attenuation of the nitrate load in the groundwater than for the chloride load in the groundwater. Results of the 3-D simulations were used to assess their counterparts based on a simplified, deterministic, 1-D vertical simulation and on limited soil monitoring. Results of the analyses suggest that the information that may be gained from a single sampling point (located close to the area active in water uptake by the tree roots) or from the results of the 1-D simulation is insufficient for a quantitative description of the response of the complicated, 3-D flow system. Both might considerably underestimate the movement and spreading of a pulse of a tracer solute and also the groundwater contamination hazard posed by nitrate and particularly by chloride moving through the vadose zone. This stems mainly from the rain that drove water through the flow system away from the rooted area and could not be represented by the 1-D model or by the single sampling point. It was shown, however, that an additional sampling point, located outside the area active in water uptake, may substantially improve the quantitative description of the response of the complicated, 3-D flow system.

Evaluation of Apical Vapor Lock Formation and comparative Evaluation of its Elimination using Three different Techniques: An in vitro Study.

PubMed

Agarwal, Anand; Deore, Rahul B; Rudagi, Kavitarani; Nanda, Zinnie; Baig, Mirza Osman; Fareez, Md Adil

2017-09-01

The aim of this study was (i) to evaluate the formation of air bubbles in the apical region of root canal (apical vapor lock) during syringe irrigation, using cone beam computed tomography (CBCT) and (ii) comparative evaluation of the elimination of an established vapor lock by EndoActivator, ultrasonics, and manual dynamic agitation (MDA), using CBCT. A total of 60 extracted human single-rooted teeth were equally divided into three groups of 20 teeth each. The samples were decoronated 17 mm from the apex, cleaned, and shaped to size F4 Protaper using 3% sodium hypochlorite. Samples were irrigated with 3% sodium hypochlorite + cesium chloride radiopaque dye, and preoperative CBCT images were obtained. After formation of apical vapor lock in the scanned teeth, EndoActivator (group I), passive ultrasonic irrigation (group II), and MDA with K-file (group III) were performed and the teeth were again placed in CBCT scanner and results analyzed using the chi-square test. The apical vapor lock was formed in all the samples. Out of the 20 teeth in each group, the apical vapor lock was eliminated in 18 samples of EndoActivator group (90%), 16 samples of ultrasonic group (80%), while it was eliminated in 10 samples by MDA (50%). It is concluded that (1) apical vapor lock is consistently formed during endodontic irrigation in closed canal systems and (2) sonic activation performs better than the ultrasonics and MDA in eliminating the apical vapor lock, with statistically significant difference between all the three groups (p < 0.05). The results suggest that the apical vapor lock (dead water zone) is consistently formed during routine endodontic irrigation which impedes irrigant penetration till the working length, thereby leading to inefficient debridement. Hence, to eliminate this vapor lock, techniques, such as sonics or ultrasonics should be used along with the irrigant after shaping and cleaning of the root canal.

Osmolarity and root canal antiseptics.

PubMed

Rossi-Fedele, G; Guastalli, A R

2014-04-01

Antiseptics used in endodontics for disinfection purposes include root canal dressings and irrigants. Osmotic shock is known to cause the alteration of microbial cell viability and might have a role in the mechanism of action of root canal antiseptics. The aim of this review was to determine the role of osmolarity on the performance of antiseptics in root canal treatment. A literature search using the Medline electronic database was conducted up to 30 May 2013 using the following search terms and combinations: 'osmolarity AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmolality AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmotic AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmosis AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; sodium chloride AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm'. Publications were included if the effects of osmolarity on the clinical performance of antiseptics in root canal treatment were stated, if preparations with different osmolarities values were compared and if they were published in English. A hand search of articles published online, 'in press' and 'early view', and in the reference list of the included papers was carried out following the same criteria. A total of 3274 publications were identified using the database, and three were included in the review. The evidence available in endodontics suggests a possible role for hyperosmotic root canal medicaments as disinfectants, and that there is no influence of osmolarity on the tissue dissolution capacity of sodium hypochlorite. There are insufficient data to obtain a sound conclusion regarding the role of hypo-osmosis in root canal disinfection, or osmosis in any further desirable ability. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

[Endodontics in motion: new concepts, materials and techniques 3. The role of irrigants during root canal treatment].

PubMed

van der Sluis, L W M

2015-10-01

The aims of root canal irrigation are the chemical dissolution or disruption and the mechanical detachment of pulp tissue, dentin debris and smear layer (instrumentation products), microorganisms (planktonic or biofilm) and their products from the root canal wall, their removal out of the root canal system and their chemical dissolution or disruption. Each of the endodontic irrigation systems has its own irrigant flow characteristics, which should fulfill these aims. Without flow (convection), the irrigant would have to be distributed through diffusion. This process is slow and depends on temperature and concentration gradients. On the other hand, convection is a faster and more efficient transport mechanism. During irrigant flow, frictional forces will occur, for example between the irrigant and the root canal wall (wall shear stress). These frictional forces have a mechanical cleaning effect on the root canal wall. These frictional forces are the result of the flow characteristics related to the different irrigation systems.

Irrigation management strategies to improve Water Use Efficiency of potatoes crop in Central Tunisia

NASA Astrophysics Data System (ADS)

Ghazouani, Hiba; Provenzano, Giuseppe; Rallo, Giovanni; Mguidiche, Amel; Douh, Boutheina; Boujelben, Abdelhamid

2015-04-01

In Tunisia, the expansion of irrigated area and the semiarid climate make it compulsory to adopt strategies of water management to increase water use efficiency. Subsurface drip irrigation (SDI), providing the application of high frequency small irrigation volumes below the soil surface have been increasingly used to enhance irrigation efficiency. At the same time, deficit irrigation (DI) has shown successful results with a large number of crop in various countries. However, for some crops like potatoes, DI is difficult to manage due to the rapid effect of water stress on tuber yield. Irrigation frequency is a key factor to schedule subsurface drip irrigation because, even maintaining the total seasonal volume, soil wetting patterns can result different during the growth period, with consequence on crop yield. Despite the need to enhance water use efficiency, only a few studies related to deficit irrigation of horticultural crops have been made in Tunisia. Objective of the paper was to assess the effects of different on-farm irrigation strategies on water use efficiency of potatoes crop irrigated with subsurface drip irrigation in a semiarid area of central Tunisia. After validation, Hydrus-2D model was used to simulate soil water status in the root zone, to evaluate actual crop evapotranspiration and then to estimate indirectly water use efficiency (IWUE), defined as the ratio between crop yield and total amount of water supplied with irrigation. Field experiments, were carried out in Central Tunisia (10° 33' 47.0" E, 35° 58' 8.1° N, 19 m a.s.l) on a potatoes crop planted in a sandy loam soil, during the growing season 2014, from January 15 (plantation of tubers) to May 6 (harvesting). Soil water status was monitored in two plots (T1 and T2) maintained under the same management, but different irrigation volumes, provided by a SDI system. In particular, irrigation was scheduled according to the average water content measured in the root zone, with a total of 8 watering, with timing ranging between one and three hours in T1, and between about half-an-hour and one-hour and a-half, in T2. The validity of Hydrus-2D model was initially assessed based on the comparison between measured and estimated soil water content at different distances from the emitter (RMSE values were not higher than 0.036). Then, model simulations allowed to verify that it is possible to enhance irrigation water use efficiency by increasing the frequency of irrigation even maintaining limited water deficit conditions during the full development stage subsequent the crop tuberization. Experimental results, joined to model simulations can therefore provide useful guidelines for a more sustainable use of irrigation water in countries characterised by semi-arid environments and limited availability of water resources.

Nine Years of Irrigation Cause Vegetation and Fine Root Shifts in a Water-Limited Pine Forest

PubMed Central

Herzog, Claude; Steffen, Jan; Graf Pannatier, Elisabeth; Hajdas, Irka; Brunner, Ivano

2014-01-01

Scots pines (Pinus sylvestris L.) in the inner-Alpine dry valleys of Switzerland have suffered from increased mortality during the past decades, which has been caused by longer and more frequent dry periods. In addition, a proceeding replacement of Scots pines by pubescent oaks (Quercus pubescens Willd.) has been observed. In 2003, an irrigation experiment was performed to track changes by reducing drought pressure on the natural pine forest. After nine years of irrigation, we observed major adaptations in the vegetation and shifts in Scots pine fine root abundance and structure. Irrigation permitted new plant species to assemble and promote canopy closure with a subsequent loss of herb and moss coverage. Fine root dry weight increased under irrigation and fine roots had a tendency to elongate. Structural composition of fine roots remained unaffected by irrigation, expressing preserved proportions of cellulose, lignin and phenolic substances. A shift to a more negative δ13C signal in the fine root C indicates an increased photosynthetic activity in irrigated pine trees. Using radiocarbon (14C) measurement, a reduced mean age of the fine roots in irrigated plots was revealed. The reason for this is either an increase in newly produced fine roots, supported by the increase in fine root biomass, or a reduced lifespan of fine roots which corresponds to an enhanced turnover rate. Overall, the responses belowground to irrigation are less conspicuous than the more rapid adaptations aboveground. Lagged and conservative adaptations of tree roots with decadal lifespans are challenging to detect, hence demanding for long-term surveys. Investigations concerning fine root turnover rate and degradation processes under a changing climate are crucial for a complete understanding of C cycling. PMID:24802642

Irrigation in endodontic treatment.

PubMed

Basrani, Bettina

2011-01-01

The primary endodontic treatment goal is to optimize root canal disinfection and to prevent reinfection. Successful root canal therapy relies on the combination of proper instrumentation, irrigation, and obturation of the root canal system. In this review of the literature, various irrigants and the interactions between irrigants are discussed and new delivery systems are introduced.

Improved soil water deficit estimation through the integration of canopy temperature measurements into a soil water balance model

USDA-ARS?s Scientific Manuscript database

Correct prediction of the dynamics of total available water in the root zone (TAWr) is critical for irrigation management as shown in the soil water balance model presented in FAO paper 56 (Allen et al., 1998). In this study, we propose a framework to improve TAWr estimation by incorporating the cro...

The effect of four different irrigation systems in the removal of a root canal sealer.

PubMed

Grischke, J; Müller-Heine, A; Hülsmann, M

2014-09-01

The aim of this study was to compare the efficiency of sonic, ultrasonic, and hydrodynamic devices in the removal of a root canal sealer from the surface and from simulated irregularities of root canals. Fifty-three root canals with two standardized grooves in the apical and coronal parts of longitudinally split roots were covered with AH Plus root canal sealer. Compared were the effects of (control) syringe irrigation, (1) CanalBrush, (2) passive ultrasonic irrigation, (3) EndoActivator, and (4) RinsEndo on the removal of the sealer. The specimens were divided into four groups (N = 12) and one control group (N = 5) via randomization. The amount of remaining sealer in the root canal irregularities was evaluated under a microscope using a 4-grade scoring system, whereas the remaining sealer on the root canal surface was evaluated with a 7-grade scoring system. Passive ultrasonic irrigation is more effective than the other tested irrigation systems or syringe irrigation in removing sealer from root canal walls (p < 0.01). None of the techniques had a significant effect on cleaning the lateral grooves. Within the limitations of this study protocol ultrasonic irrigation shows a superior effect on sealer removal from the root canal surface during endodontic retreatment. Cleaning of lateral grooves seems not to be possible with one of the techniques investigated. Incomplete removal of root canal sealer during re-treatment may cause treatment failure. Passive Ultrasonic irrigation seems to be the most effective system to remove sealer from a root canal.

Numerical Modeling of Water Fluxes in the Root Zone of Irrigated Pecan

NASA Astrophysics Data System (ADS)

Shukla, M. K.; Deb, S.

2010-12-01

Information is still limited on the coupled liquid water, water vapor, heat transport and root water uptake for irrigated pecan. Field experiments were conducted in a sandy loam mature pecan field in Las Cruces, New Mexico. Three pecan trees were chosen to monitor diurnal soil water content under the canopy (approximately half way between trunk and the drip line) and outside the drip line (bare spot) along a transect at the depths of 5, 10, 20, 40, and 60 cm using TDR sensors. Soil temperature sensors were installed at an under-canopy locations and bare spot to monitor soil temperature data at depths of 5, 10, 20, and 40 cm. Simulations of the coupled transport of liquid water, water vapor, and heat with and without root water uptake were carried out using the HYDRUS-1D code. Measured soil hydraulic and thermal properties, continuous meteorological data, and pecan characteristics, e.g. rooting depth, leaf area index, were used in the model simulations. Model calibration was performed for a 26-day period from DOY 204 through DOY 230, 2009 based on measured soil water content and soil temperature data at different soil depths, while the model was validated for a 90-day period from DOY 231 through DOY 320, 2009 at bare spot. Calibrated parameters were also used to apply the model at under-canopy locations for a 116-day period from DOY 204 to 320. HYDRUS-1D simulated water contents and soil temperatures correlated well with the measured data at each depth. Numerical assessment of various transport mechanisms and quantitative estimates of isothermal and thermal water fluxes with and without root water uptake in the unsaturated zone within canopy and bare spot is in progress and will be presented in the conference.

Simulating spatial and temporal variation of corn canopy temperature during an irrigation cycle

NASA Technical Reports Server (NTRS)

Choudhury, B. J.; Federer, C. A.

1983-01-01

The canopy air temperature difference (delta T) which provides an index for scheduling irrigation was examined. The Monteith transpiration equation was combined with both uptake from a single layered root zone and change in internal storage of the plant and the continuity equation for water flux in the soil plant atmosphere system was solved. The model indicates that both daily total transpiration and soil induced depression of plant water potential may be inferred from mid-day delta T. It is suggested that for the soil plant weather data used in the simulation, either a mid day spatial variability of about 0.8K in canopy temperatures or a field averaged delta T of 2 to 4K may be a suitable criterion for irrigation scheduling.

Effect of Passive Ultrasonic Irrigation on Enterococcus faecalis from Root Canals: An Ex Vivo Study.

PubMed

Guerreiro-Tanomaru, Juliane Maria; Chávez-Andrade, Gisselle Moraima; de Faria-Júnior, Norberto Batista; Watanabe, Evandro; Tanomaru-Filho, Mário

2015-01-01

Endodontic irrigation aims to clean and disinfect the root canal system. Passive ultrasonic irrigation (PUI) is based on the use of an ultrasound-activated instrument into the root canal filled with irrigant. The aim of this study was to evaluate, ex vivo, the effectiveness of PUI in eliminating Enterococcus faecalis from root canals. Seventy-five extracted human single-root teeth were used. After root canal preparation, specimens were inoculated with E. faecalis and incubated at 37 °C for 21 days. Specimens were distributed into five groups (n=15), according to the irrigation method: PUI + saline solution (PUI/SS); PUI + 1% NaOCl (PUI/NaOCl); conventional needle irrigation (CNI) + saline solution (CNI/SS); CNI + 1% NaOCl (CNI/NaOCl); No irrigation (control). Microbiological samples were collected at three time points: initial (21 days after inoculation), post-irrigation (immediately after irrigation), and final (7 days after irrigation). Data were obtained in CFU mL-1 and subjected to analysis by ANOVA and Tukey's tests at 5% significance level. The post-irrigation samples did not demonstrate statistical difference between PUI/SS and CNI/SS nor between PUI/NaOCl and CNI/NaOCl (p>0.05), but PUI/NaOCl and CNI/NaOCl had lower CFU mL-1 number than the other groups (p>0.05). Statistically significant difference was observed between the initial and post-irrigation samples and between the post-irrigation and final samples (p<0.05) in all groups, except in the control. The final samples of all groups presented bacterial counts similar to the initial samples. PUI or CNI with 1% NaOCl contribute to disinfection, but are unable to eradicate E. faecalis from the root canal system.

Validation and application of a two-dimensional model to simulate soil salt transport under mulched drip irrigation

NASA Astrophysics Data System (ADS)

Jiao, Huiqing; Zhao, Chengyi; Sheng, Yu; Chen, Yan; Shi, Jianchu; Li, Baoguo

2017-04-01

Water shortage and soil salinization increasingly become the main constraints for sustainable development of agriculture in Southern Xinjiang, China. Mulched drip irrigation, as a high-efficient water-saving irrigation method, has been widely applied in Southern Xinjiang for cotton production. In order to analyze the reasonability of describing the three-dimensional soil water and salt transport processes under mulched drip irrigation with a relatively simple two-dimensional model, a field experiment was conducted from 2007 to 2015 at Aksu of Southern Xinjiang, and soil water and salt transport processes were simulated through the three-dimensional and two-dimensional models based on COMSOL. Obvious differences were found between three-dimensional and two-dimensional simulations for soil water flow within the early 12 h of irrigation event and for soil salt transport in the area within 15 cm away from drip tubes during the whole irrigation event. The soil water and salt contents simulated by the two-dimensional model, however, agreed well with the mean values between two adjacent emitters simulated by the three-dimensional model, and also coincided with the measurements as corresponding RMSE less than 0.037 cm3 cm-3 and 1.80 g kg-1, indicating that the two-dimensional model was reliable for field irrigation management. Subsequently, the two-dimensional model was applied to simulate the dynamics of soil salinity for five numerical situations and for a widely adopted irrigation pattern in Southern Xinjiang (about 350 mm through mulched drip irrigation during growing season of cotton and total 400 mm through flooding irrigations before sowing and after harvesting). The simulation results indicated that the contribution of transpiration to salt accumulation in root layer was about 75% under mulched drip irrigation. Moreover, flooding irrigations before sowing and after harvesting were of great importance for salt leaching of arable layer, especially in bare strip where drip irrigation water hardly reached, and thus providing suitable root zone environment for cotton. Nevertheless, flooding irrigation should be further optimized to enhance water use efficiency.

Effect of Peracetic Acid as A Final Rinse on Push Out Bond Strength of Root Canal Sealers to Root Dentin.

PubMed

Gaddala, Naresh; Veeramachineni, Chandrasekhar; Tummala, Muralidhar

2015-05-01

Smear layer which was formed during the instrumentation of root canals hinders the penetration of root canal sealers to root dentin and affect the bond strength of root canal sealers to root dentin. Final irrigant such as demineralizing agents are used to remove the inorganic portion of the smear layer. In the present study, peracetic acid used as a final rinse, to effect the bond strength of root canal sealers to root dentin. The purpose of the present study was to evaluate the efficacy of peracetic acid as a final irrigant on bond strength of root canal sealers to root dentin. Sixty six freshly extracted human single rooted mandibular premolars were used for this study. After decoronation the samples were instrumented with Protaper upto F3 and irrigated with 5.25% NaOcl. The teeth were then divided into three groups based on final irrigant used: Group-1(control group) Canals were irrigated with distilled water. Group-2: Canals were irrigated with peracetic acid. Group-3: Canals were irrigated with smear clear. Each group was further divided into three subgroups (n=30) based on the sealer used to obturate the canals. Subgroup-1: kerr, Subgroup-2: Apexit plus, Subgroup-3: AH PLUS. Each sealer was mixed and coated to master cone and placed in the canal. The bonding between sealer and dentin surface was evaluated using push out bond strength by universal testing machine. The mean bond strength values of each group were statistically evaluated using Two-way ANOVA followed by Tukey post-hoc test. Significant difference was found among the bond strength of the sealers. But, there is no statistically significant difference between the groups irrigated with peracetic acid and smear clear compared to control group. AH Plus showed highest bond strength irrespective of the final irrigant used. Peracetic acid when employed as final irrigant improved the bond strength of root canal sealers compared to control group but not statistically significant than smear clear.

Effect of Peracetic Acid as A Final Rinse on Push Out Bond Strength of Root Canal Sealers to Root Dentin

PubMed Central

Gaddala, Naresh; Veeramachineni, Chandrasekhar

2015-01-01

Background Smear layer which was formed during the instrumentation of root canals hinders the penetration of root canal sealers to root dentin and affect the bond strength of root canal sealers to root dentin. Final irrigant such as demineralizing agents are used to remove the inorganic portion of the smear layer. In the present study, peracetic acid used as a final rinse, to effect the bond strength of root canal sealers to root dentin. Aim The purpose of the present study was to evaluate the efficacy of peracetic acid as a final irrigant on bond strength of root canal sealers to root dentin. Materials and Methods Sixty six freshly extracted human single rooted mandibular premolars were used for this study. After decoronation the samples were instrumented with Protaper upto F3 and irrigated with 5.25% NaOcl. The teeth were then divided into three groups based on final irrigant used: Group-1(control group) Canals were irrigated with distilled water. Group-2: Canals were irrigated with peracetic acid. Group-3: Canals were irrigated with smear clear. Each group was further divided into three subgroups (n=30) based on the sealer used to obturate the canals. Subgroup-1: kerr, Subgroup-2: Apexit plus, Subgroup-3: AH PLUS. Each sealer was mixed and coated to master cone and placed in the canal. The bonding between sealer and dentin surface was evaluated using push out bond strength by universal testing machine. The mean bond strength values of each group were statistically evaluated using Two-way ANOVA followed by Tukey post-hoc test. Results Significant difference was found among the bond strength of the sealers. But, there is no statistically significant difference between the groups irrigated with peracetic acid and smear clear compared to control group. AH Plus showed highest bond strength irrespective of the final irrigant used. Conclusion Peracetic acid when employed as final irrigant improved the bond strength of root canal sealers compared to control group but not statistically significant than smear clear. PMID:26155568

Community Dynamics of Arbuscular Mycorrhizal Fungi in High-Input and Intensively Irrigated Rice Cultivation Systems

PubMed Central

Wang, Yutao; Li, Ting; Li, Yingwei; Björn, Lars Olof; Rosendahl, Søren; Olsson, Pål Axel; Fu, Xuelin

2015-01-01

Application of a mycorrhizal inoculum could be one way to increase the yield of rice plants and reduce the application of fertilizer. We therefore studied arbuscular mycorrhizal fungi (AMF) in the roots of wetland rice (Oryza sativa L.) collected at the seedling, tillering, heading, and ripening stages in four paddy wetlands that had been under a high-input and intensively irrigated rice cultivation system for more than 20 years. It was found that AMF colonization was mainly established in the heading and ripening stages. The AMF community structure was characterized in rhizosphere soils and roots from two of the studied paddy wetlands. A fragment covering the partial small subunit (SSU), the whole internal transcribed spacer (ITS), and the partial large subunit (LSU) rRNA operon regions of AMF was amplified, cloned, and sequenced from roots and soils. A total of 639 AMF sequences were obtained, and these were finally assigned to 16 phylotypes based on a phylogenetic analysis, including 12 phylotypes from Glomeraceae, one phylotype from Claroideoglomeraceae, two phylotypes from Paraglomeraceae, and one unidentified phylotype. The AMF phylotype compositions in the soils were similar between the two surveyed sites, but there was a clear discrepancy between the communities obtained from root and soil. The relatively high number of AMF phylotypes at the surveyed sites suggests that the conditions are suitable for some species of AMF and that they may have an important function in conventional rice cultivation systems. The species richness of root-colonizing AMF increased with the growth of rice, and future studies should consider the developmental stages of this crop in the exploration of AMF function in paddy wetlands. PMID:25681190

Community dynamics of arbuscular mycorrhizal fungi in high-input and intensively irrigated rice cultivation systems.

PubMed

Wang, Yutao; Li, Ting; Li, Yingwei; Björn, Lars Olof; Rosendahl, Søren; Olsson, Pål Axel; Li, Shaoshan; Fu, Xuelin

2015-04-01

Application of a mycorrhizal inoculum could be one way to increase the yield of rice plants and reduce the application of fertilizer. We therefore studied arbuscular mycorrhizal fungi (AMF) in the roots of wetland rice (Oryza sativa L.) collected at the seedling, tillering, heading, and ripening stages in four paddy wetlands that had been under a high-input and intensively irrigated rice cultivation system for more than 20 years. It was found that AMF colonization was mainly established in the heading and ripening stages. The AMF community structure was characterized in rhizosphere soils and roots from two of the studied paddy wetlands. A fragment covering the partial small subunit (SSU), the whole internal transcribed spacer (ITS), and the partial large subunit (LSU) rRNA operon regions of AMF was amplified, cloned, and sequenced from roots and soils. A total of 639 AMF sequences were obtained, and these were finally assigned to 16 phylotypes based on a phylogenetic analysis, including 12 phylotypes from Glomeraceae, one phylotype from Claroideoglomeraceae, two phylotypes from Paraglomeraceae, and one unidentified phylotype. The AMF phylotype compositions in the soils were similar between the two surveyed sites, but there was a clear discrepancy between the communities obtained from root and soil. The relatively high number of AMF phylotypes at the surveyed sites suggests that the conditions are suitable for some species of AMF and that they may have an important function in conventional rice cultivation systems. The species richness of root-colonizing AMF increased with the growth of rice, and future studies should consider the developmental stages of this crop in the exploration of AMF function in paddy wetlands. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Root-Zone Redox Dynamics - In Search for the Cause of Damage to Treated-Wastewater Irrigated Orchards in Clay Soils

NASA Astrophysics Data System (ADS)

Yalin, David; Shenker, Moshe; Schwartz, Amnon; Assouline, Shmuel; Tarchitzky, Jorge

2016-04-01

Treated wastewater (TW) has become a common source of water for agriculture. However recent findings raise concern regarding its use: a marked decrease (up to 40%) in yield appeared in orchards irrigated with TW compared with fresh water (FW) irrigated orchards. These detrimental effects appeared predominantly in orchards cultivated in clay soils. The association of the damage with clay soils rather than sandy soils led us to hypothesize that the damage is linked to soil aeration problems. We suspected that in clay soils, high sodium adsorption ratio (SAR) and high levels of organic material, both typical of TW, may jointly lead to an extreme decrease in soil oxygen levels, so as to shift soil reduction-oxidation (redox) state down to levels that are known to damage plants. Two-year continuous measurement of redox potential, pH, water tension, and oxygen were conducted in the root-zone (20-35 cm depth) of avocado trees planted in clay soil and irrigated with either TW or FW. Soil solution composition was sampled periodically in-situ and mineral composition was sampled in tree leaves and woody organs biannually. In dry periods the pe+pH values indicated oxic conditions (pe+pH>14), and the fluctuations in redox values were small in both TW and FW plots. Decreases in soil water tension following irrigation or rain were followed by drops in soil oxygen and pe+pH values. TW irrigated plots had significantly lower minimum pe+pH values compared with FW-irrigated plots, the most significant differences occurred during the irrigation season rather than the rain season. A linear correlation appeared between irrigation volume and reduction severity in TW-irrigated plots, but not in the FW plots, indicating a direct link to the irrigation regime in TW-irrigated plots. The minimum pe+pH values measured in the TW plots are indicative of suboxic conditions (9

Apoplastic Alkalinization Is Instrumental for the Inhibition of Cell Elongation in the Arabidopsis Root by the Ethylene Precursor 1-Aminocyclopropane-1-Carboxylic Acid1[W][OA

PubMed Central

Staal, Marten; De Cnodder, Tinne; Simon, Damien; Vandenbussche, Filip; Van Der Straeten, Dominique; Verbelen, Jean-Pierre; Elzenga, Theo; Vissenberg, Kris

2011-01-01

In Arabidopsis (Arabidopsis thaliana; Columbia-0) roots, the so-called zone of cell elongation comprises two clearly different domains: the transition zone, a postmeristematic region (approximately 200–450 μm proximal of the root tip) with a low rate of elongation, and a fast elongation zone, the adjacent proximal region (450 μm away from the root tip up to the first root hair) with a high rate of elongation. In this study, the surface pH was measured in both zones using the microelectrode ion flux estimation technique. The surface pH is highest in the apical part of the transition zone and is lowest at the basal part of the fast elongation zone. Fast cell elongation is inhibited within minutes by the ethylene precursor 1-aminocyclopropane-1-carboxylic acid; concomitantly, apoplastic alkalinization occurs in the affected root zone. Fusicoccin, an activator of the plasma membrane H+-ATPase, can partially rescue this inhibition of cell elongation, whereas the inhibitor N,N′-dicyclohexylcarbodiimide does not further reduce the maximal cell length. Microelectrode ion flux estimation experiments with auxin mutants lead to the final conclusion that control of the activity state of plasma membrane H+-ATPases is one of the mechanisms by which ethylene, via auxin, affects the final cell length in the root. PMID:21282405

Impact of Various Irrigating Agents on Root Fracture: An in vitro Study.

PubMed

Tiwari, Sukriti; Nikhade, Pradnya; Chandak, Manoj; Sudarshan, C; Shetty, Priyadarshini; Gupta, Naveen K

2016-08-01

Irrigating solutions are used for cleaning and removing dentinal debris, and the other remains from pulpal space during biomechanical preparation. Therefore, we evaluated the impact of various irrigating agents on root fracture at 5-minute time exposure. We sectioned 60 permanent maxillary premolars with fully formed root structures transversely maintaining the root length of approximately 14 mm. Five study groups were made comprising ethylenediaminetetraacetic acid (EDTA), cetrimide, citric acid, and so on as various irrigating agents. A universal force test machine was used to calculate the force which was enough to fracture each root. Analysis of variance (ANOVA) test was used to access the level of significance. About 10% citric acid solution as an irrigating agent showed minimal fracture opposing results, whereas 10% EDTA solution showed the maximum fracture resistance of root portion. Selection of suitable EDTA concentration that has minimal adverse effect on the mechanical properties of the tooth is very important for the successful management of tooth fracture. About 10% EDTA provided the highest fracture resistance, necessitating the use of irrigating solution in root canal therapy (RCT). Further research with higher and different study groups is required to search for more efficient irrigating solution to improve the outcome of RCT.

Comparison of positive-pressure, passive ultrasonic, and laser-activated irrigations on smear-layer removal from the root canal surface.

PubMed

Sahar-Helft, Sharonit; Sarp, Ayşe Sena Kabaş; Stabholtz, Adam; Gutkin, Vitaly; Redenski, Idan; Steinberg, Doron

2015-03-01

The purpose of this study was to compare the efficacy of three irrigation techniques for smear-layer removal with 17% EDTA. Cleaning and shaping the root canal system during endodontic treatment produces a smear layer and hard tissue debris. Three irrigation techniques were tested for solution infiltration of this layer: positive-pressure irrigation, passive ultrasonic irrigation, and laser-activated irrigation. Sixty extracted teeth were divided into six equal groups; 17% EDTA was used for 60 sec irrigation of five of the groups. The groups were as follows: Group 1, treated only with ProTaper™ F3 Ni-Ti files; Group 2, positive-pressure irrigation, with a syringe; Group 3, passive ultrasonic irrigation, inserted 1 mm short of the working length; Group 4, passive ultrasonic irrigation, inserted in the upper coronal third of the root; Group 5, Er:YAG laser-activated irrigation, inserted 1 mm short of the working length; and Group 6, Er:YAG laser-activated irrigation, inserted in the upper coronal third of the root. Scanning electron microscopy showed that the smear layer is removed most efficiently using laser-activated irrigation at low energy with 17% EDTA, inserted either at the working length or only in the coronal upper third of the root. Amounts of Ca, P, and O were not significantly different on all treated dentin surfaces. Smear-layer removal was most effective when the root canals were irrigated using Er:YAG laser at low energy with 17% EDTA solution. Interestingly, removal of the smear layer along the entire canal was similar when the laser was inserted in the upper coronal third and at 1 mm short of the working length of the root canal. This effect was not observed with the ultrasonic and positive-pressure techniques.

Safe and High Quality Food Production using Low Quality Waters and Improved Irrigation Systems and Management (SAFIR)

NASA Astrophysics Data System (ADS)

Cary, L.; Kloppmann, W.; Battilani, A.; Bertaki, M.; Blagojevic, S.; Chartzoulakis, K.; Dalsgaard, A.; Forslund, A.; Jovanovic, Z.; Kasapakis, I.

2009-04-01

The safe use of treated domestic wastewater for irrigation needs to address the risks for humans (workers, exposed via contact with irrigation water, soil, crops and food, consumers, exposed via ingestion of fresh and processed food), for animals (via ingestion of crops an soil), for the crops and agricultural productivity (via salinity and trace element uptake), for soil (via accumulation or release of pollutants) as well as for surface, groundwaters and the associated ecosystems (via runoff and infiltration, Kass et al., 2005, Bouwer, 2000). A work package in the EU FP5 project SAFIR is dedicated to study the impact of wastewater irrigation on the soil-water-plant-product system. Its monitoring program comprises pathogens and inorganic pollutants, including both geogenic and potentially anthropogenic trace elements in the aim to better understand soil-irrigation water interactions. The SAFIR field study sites are found in China, Italy, Crete, and Serbia. A performance evaluation of SAFIR-specific treatment technology through the monitoring of waste water and irrigation water quality was made through waste water chemical and microbiological qualities, which were investigated upstream and downstream of the SAFIR specific treatment three times per season. Irrigation water transits through the uppermost soil decimetres to the crop roots. The latter will become, in the course of the irrigation season, the major sink of percolating water, together with evaporation. The water saving irrigation techniques used in SAFIR are surface and subsurface drip irrigation. The investigation of the solid soil phase concentrates on the root zone as main transit and storage compartment for pollutants and, eventually, pathogens. The initial soil quality was assessed through a sampling campaign before the onset of the first year irrigation; the soil quality has been monitored throughout three years under cultivation of tomatoes or potatoes. The plot layout for each of the study sites allows comparing different combinations of (1) water quality, including tap water as a reference, (2) irrigation techniques, and (3) irrigation strategies (including full irrigation, partial root drying, RDI). The replication of each of the combinations on three different plots takes into account the local variations of soil properties and allows a proper statistical treatment. Reactions of the infiltrating water with the soil solid phase are important for the solute cycling, temporary fixation and remobilisation of trace pollutants. The type of reaction (sorption, co-precipitation…) and the reactive mineral phases will also determine the availability of trace elements for the plant and determine the passage towards crops and products. Therefore it is important to assess the soil water quality, directly or indirectly. Direct measurements of soil water imply soil water sampling through an appropriate system; porous cups were installed on the Cretan, Italian and Chinese sites. Indirect evaluation of water-soil interactions can be obtained through sequential extractions. The combination of a variable input function (through diffuse pollution, irrigation, fertigation) and of variable MTE mobility in soils can be expected to lead to short term variations in soil metal concentrations even if such short term variations have been rarely investigated (Féder, 2001; Cary and Trolard, 2008). The sampling focused upon the fully irrigated plots given that the potential impact of irrigation water quality on soil and plant quality can be expected higher for fully irrigated soils compared to other irrigation strategies. Samples were taken within the soil volume of potential influence around each of the drip emitters. This volume varies depending on the nature of the soil and the irrigation system so that each site adopted a specific protocol. For all experiments, three sampling campaigns were scheduled for each irrigation season: at pre-planting, at the end of irrigation, at harvest. The geochemical evolution of soil properties over the 3 years shows significant variations in major and minor elements, especially trace metallic elements. It implies the role of the cultivated plant as a sink of elements which leads to direct loss of elements in the soil system. Bouwer, H., 2000. Groundwater problems caused by irrigation with sewage effluent. Journal of Environmental Health 63, 17-20. Cary L., Trolard F. (2008). Metal mobility in the ground water of a paddy field in Camargue (South eastern France). Journal of Geochemical Exploration 96/2-3 : 132-143. Féder, 2001. Dynamique des processus d'oxydo-reduction dans les sols hydromorphes, These de l'Universite Aix Marseille III. Kass, A. Gavrieli, I. Yechieli, Y. Vengosh A.and Starinsky, A., 2005. The impact of freshwater and wastewater irrigation on the chemistry of shallow groundwater: a case study from the Israeli Coastal Aquifer, Journal of Hydrology, 300, 314-331.

Assessment of the soil water balance by the combination of cosmic ray neutron sensing and eddy covariance technique in an irrigated citrus orchard (Marrakesh, Morocco)

NASA Astrophysics Data System (ADS)

Mroos, Katja; Baroni, Gabriele; Er-Raki, Salah; Francke, Till; Khabba, Said; Jarlan, Lionel; Hanich, Lahoucine; Oswald, Sascha E.

2014-05-01

Irrigation water requirement plays a crucial role in many agricultural areas and especially in arid and semi-arid landscapes. Improvements in the water management and the performance of the irrigation systems require a correct evaluation of the hydrological processes involved. However, some difficulties can arise due to the heterogeneity of the soil-plant system and of the irrigation scheme. To overcome these limitations, in this study, the soil water balance is analyzed by the combination of the Eddy Covariance technique (EC) and Cosmic Ray neutron Sensing (CRS). EC provides the measurement of the actual evapotranspiration over the area as it was presented in many field conditions. Moreover CRS showed to be a valuable approach to measure the root zone soil moisture integrated in a footprint of ~30 ha. In this way, the combination of the two methodologies should provide a better analysis of the soil water balance at field scale, as opposed to point observations, e.g. by TDR, evaporimeter and fluxmeter. Then, this could increase the capability to assess the irrigation efficiency and the agricultural water management. The study is conducted in a citrus orchard situated in a semi-arid region, 30 km southwest of Marrakesh (Morocco). The site is flat and planted with trees of same age growing in parallel rows with drip irrigation lines and application of fertilizer and pesticides. The original soil seems modified on the surface by the agricultural use, creating differences between trees, rows and lines. In addition, the drip irrigation creates also a spatial variability of the water flux distribution in the field, making this site an interesting area to test the methodology. Particular attention is given to the adaptation of the standard soil sampling campaign used for the calibration of the CRS and the introduction of a weighing function. Data were collected from June to December 2013, which corresponds to the high plant transpiration. Despite the intention of the farmer to maintain constant soil water contents in the root zone throughout the period, the CRS results showed a relatively strong dynamic of the soil water conditions at field scale and respond well to the EC measurements. Strong spatial heterogeneities and the difficulties of direct comparison between the different scales of measurements pose a challenge for full quantification of the water balance. Further analysis will address the assessment of the irrigation efficiency at different scales and of deep percolation. Keywords: Cosmic Ray Sensing, deep percolation, Eddy Covariance, evapotranspiration, irrigation, Morocco, soil moisture, semi-arid;

Combined effects of photodynamic therapy and irrigants in disinfection of root canals.

PubMed

Susila, Anand V; Sugumar, R; Chandana, C S; Subbarao, C V

2016-06-01

In this study, the combined effects of photodynamic therapy and irrigants in eradicating common endodontic pathogens are evaluated. Roots of 80 extracted single rooted teeth are divided into 2 groups (1) mechanical flushing; (2) antibacterial irrigation. After cleaning and shaping, they are inoculated with either (A) Streptococcus mutans or (B) Enterococcus faecalis and incubated. They are again subdivided and either only irrigated or irrigated and lased. Dentin shavings are taken from root canal walls and cultured. Statistical analysis using One-Way ANOVA and Post-hoc tests are done. The combination eradicated both bacteria. Antibacterial irrigants controlled S. mutans better than PDT (p = 0.041). The combination of PDT and antibacterial irrigation proposed in this study can be used in all primary cases for thorough and reliable disinfection of root canals but may be highly effective in resistant cases like endodontic failures, as E. faecalis is prevalent in such cases. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Unusual Root Canal Irrigation Solutions.

PubMed

Mohammadi, Zahed; Jafarzadeh, Hamid; Shalavi, Sousan; Kinoshita, Jun-Ichiro

2017-05-01

Microorganisms and their by-products play a critical role in pulp and periradicular pathosis. Therefore, one of the main purposes of root canal treatment is disinfection of the entire system of the canal. This aim may be obtained using mechanical preparation, chemical irrigation, and temporary medication of the canal. For this purpose, various irrigation solutions have been advocated. Common root canal irrigants, such as sodium hypochlorite, chlorhexidine, and a mixture of tetracycline, acid, and detergent have been extensively reviewed. The aim of this review was to address the less common newer root canal irrigation solutions, such as citric acid, maleic acid, electrochemically activated water, green tea, ozonated water, and SmearClear.

Microcystin-LR-induced phytotoxicity in rice crown root is associated with the cross-talk between auxin and nitric oxide.

PubMed

Chen, Jian; Zhang, Hai-Qiang; Hu, Liang-Bin; Shi, Zhi-Qi

2013-09-01

Irrigation with cyanobacterial-blooming water containing microcystin-LR (MC-LR) poses threat to the growth of agricultural plants. Large amounts of rice (Oryza sativa) field in the middle part of China has been irrigating with cyanobacterial-blooming water. Nevertheless, the mechanism of MC-LR-induced phytotoxicity in the root of monocot rice remains unclear. In the present study, we demonstrate that MC-LR stress significantly inhibits the growth of rice root by impacting the morphogenesis rice crown root. MC-LR treatment results in the decrease in IAA (indole-3-acetic acid) concentration as well as the expression of CRL1 and WOX11 in rice roots. The application of NAA (1-naphthylacetic acid), an IAA homologue, is able to attenuate the inhibitory effect of MC-LR on rice root development. MC-LR treatment significantly inhibits OsNia1-dependent NO generation in rice roots. The application of NO donor SNP (sodium nitroprusside) is able to partially reverse the inhibitory effects of MC-LR on the growth of rice root and the expression of CRL1 and WOX11 by enhancing endogenous NO level in rice roots. The application of NO scavenger cPTIO [2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylinidazoline-1-oxyl-3-oxide] eliminates the effects of SNP. Treatment with NAA stimulates the generation of endogenous NO in MC-LR-treated rice roots. Treatment with NO scavenger cPTIO abolishes the ameliorated effect of NAA on MC-LR-induced growth inhibition of rice root. Treatment with SNP enhanced IAA concentration in MC-LR-treated rice roots. Altogether, our data suggest that NO acts both downstream and upstream of auxin in regulating rice root morphogenesis under MC-LR stress. Copyright © 2013 Elsevier Ltd. All rights reserved.

Irrigation of human prepared root canal – ex vivo based computational fluid dynamics analysis

PubMed Central

Šnjarić, Damir; Čarija, Zoran; Braut, Alen; Halaji, Adelaida; Kovačević, Maja; Kuiš, Davor

2012-01-01

Aim To analyze the influence of the needle type, insertion depth, and irrigant flow rate on irrigant flow pattern, flow velocity, and apical pressure by ex-vivo based endodontic irrigation computational fluid dynamics (CFD) analysis. Methods Human upper canine root canal was prepared using rotary files. Contrast fluid was introduced in the root canal and scanned by computed tomography (CT) providing a three-dimensional object that was exported to the computer-assisted design (CAD) software. Two probe points were established in the apical portion of the root canal model for flow velocity and pressure measurement. Three different CAD models of 27G irrigation needles (closed-end side-vented, notched open-end, and bevel open-end) were created and placed at 25, 50, 75, and 95% of the working length (WL). Flow rates of 0.05, 0.1, 0.2, 0.3, and 0.4 mL/s were simulated. A total of 60 irrigation simulations were performed by CFD fluid flow solver. Results Closed-end side-vented needle required insertion depth closer to WL, regarding efficient irrigant replacement, compared to open-end irrigation needle types, which besides increased velocity produced increased irrigant apical pressure. For all irrigation needle types and needle insertion depths, the increase of flow rate was followed by an increased irrigant apical pressure. Conclusions The human root canal shape obtained by CT is applicable in the CFD analysis of endodontic irrigation. All the analyzed values –irrigant flow pattern, velocity, and pressure – were influenced by irrigation needle type, as well as needle insertion depth and irrigant flow rate. PMID:23100209

Irrigation of human prepared root canal--ex vivo based computational fluid dynamics analysis.

PubMed

Snjaric, Damir; Carija, Zoran; Braut, Alen; Halaji, Adelaida; Kovacevic, Maja; Kuis, Davor

2012-10-01

To analyze the influence of the needle type, insertion depth, and irrigant flow rate on irrigant flow pattern, flow velocity, and apical pressure by ex-vivo based endodontic irrigation computational fluid dynamics (CFD) analysis. Human upper canine root canal was prepared using rotary files. Contrast fluid was introduced in the root canal and scanned by computed tomography (CT) providing a three-dimensional object that was exported to the computer-assisted design (CAD) software. Two probe points were established in the apical portion of the root canal model for flow velocity and pressure measurement. Three different CAD models of 27G irrigation needles (closed-end side-vented, notched open-end, and bevel open-end) were created and placed at 25, 50, 75, and 95% of the working length (WL). Flow rates of 0.05, 0.1, 0.2, 0.3, and 0.4 mL/s were simulated. A total of 60 irrigation simulations were performed by CFD fluid flow solver. Closed-end side-vented needle required insertion depth closer to WL, regarding efficient irrigant replacement, compared to open-end irrigation needle types, which besides increased velocity produced increased irrigant apical pressure. For all irrigation needle types and needle insertion depths, the increase of flow rate was followed by an increased irrigant apical pressure. The human root canal shape obtained by CT is applicable in the CFD analysis of endodontic irrigation. All the analyzed values -irrigant flow pattern, velocity, and pressure - were influenced by irrigation needle type, as well as needle insertion depth and irrigant flow rate.

Cutaneous Sinus Tract from Mandibular Second Molar with C-shaped Canal System and Improper Former Root Canal Treatment: A Case Report.

PubMed

Gharechahi, Maryam; Dastmalchi, Parisa

2016-01-01

Here, we report the diagnosis and treatment of an extraoral cutaneous sinus tract originating in a mandibular second molar with a C-shaped root canal system. The patient was referred to our department by a dermatologist after a series of unsuccessful treatments, including antibiotics. Diffuse radiolucency on a preoperative radiograph revealed that earlier root canal treatment had been only partially successful. Consequently, we performed retreatment of the root canal comprising removal of the former restoration and gutta-percha, cleaning and shaping, and passive irrigation with sodium hypochlorite. The patient responded well, and the cutaneous lesion completely resolved uneventfully within 1 month postoperatively. Preoperative recognition and thorough knowledge of the root canal anatomy and conventional methods of obturation are necessary in performing successful endodontic treatment.

Efficacy of passive ultrasonic irrigation with natural irrigants (Morinda citrifolia juice, Aloe Vera and Propolis) in comparison with 1% sodium hypochlorite for removal of E. faecalis biofilm: an in vitro study.

PubMed

Bhardwaj, Anuj; Velmurugan, Natanasabapathy; Ballal, Suma

2013-01-01

Present study evaluated the efficacy of natural derivative irrigants, Morinda citrifolia juice (MCJ), Aloe Vera and Propolis in comparison to 1% sodium hypochlorite with passive ultrasonic irrigation for removal of the intraradicular E. faecalis biofilms in extracted single rooted human permanent teeth. Biofilms of E. faecalis were grown on the prepared root canal walls of 60 standardized root halves which were longitudinally sectioned. These root halves were re-approximated and the samples were divided into five groups of twelve each. The groups were, Group A (1% NaOCl), Group B (MCJ), Group C (Aloe vera), Group D (Propolis) and Group E (Saline). These groups were treated with passive ultrasonic irrigation (PUI) along with the respective irrigants. The root halves were processed for scanning electron microscopy. Three images (X2.5), coronal, middle and apical, were taken for the twelve root halves in each of the five groups. The images were randomized and biofilm coverage assessed independently by three calibrated examiners, using a four-point scoring system. 1% NaOCl with passive ultrasonic irrigation (PUI) was effective in completely removing E. faecalis biofilm and was superior to the natural irrigants like MCJ, Aloe vera and Propolis tested in this study. 1% NaOCl used along with passive ultrasonic irrigation was effective in completely removing E. faecalis biofilm when compared to natural irrigants (MCJ, Aloe Vera and Propolis).

Differentiating transpiration from evaporation in seasonal agricultural wetlands and the link to advective fluxes in the root zone

USGS Publications Warehouse

Bachand, P.A.M.; S. Bachand,; Fleck, Jacob A.; Anderson, Frank E.; Windham-Myers, Lisamarie

2014-01-01

The current state of science and engineering related to analyzing wetlands overlooks the importance of transpiration and risks data misinterpretation. In response, we developed hydrologic and mass budgets for agricultural wetlands using electrical conductivity (EC) as a natural conservative tracer. We developed simple differential equations that quantify evaporation and transpiration rates using flowrates and tracer concentrations atwetland inflows and outflows. We used two ideal reactormodel solutions, a continuous flowstirred tank reactor (CFSTR) and a plug flow reactor (PFR), to bracket real non-ideal systems. From those models, estimated transpiration ranged from 55% (CFSTR) to 74% (PFR) of total evapotranspiration (ET) rates, consistent with published values using standard methods and direct measurements. The PFR model more appropriately represents these nonideal agricultural wetlands in which check ponds are in series. Using a fluxmodel, we also developed an equation delineating the root zone depth at which diffusive dominated fluxes transition to advective dominated fluxes. This relationship is similar to the Peclet number that identifies the dominance of advective or diffusive fluxes in surface and groundwater transport. Using diffusion coefficients for inorganic mercury (Hg) and methylmercury (MeHg) we calculated that during high ET periods typical of summer, advective fluxes dominate root zone transport except in the top millimeters below the sediment–water interface. The transition depth has diel and seasonal trends, tracking those of ET. Neglecting this pathway has profound implications: misallocating loads along different hydrologic pathways; misinterpreting seasonal and diel water quality trends; confounding Fick's First Law calculations when determining diffusion fluxes using pore water concentration data; and misinterpreting biogeochemicalmechanisms affecting dissolved constituent cycling in the root zone. In addition,our understanding of internal root zone cycling of Hg and other dissolved constituents, benthic fluxes, and biological irrigation may be greatly affected.

Modelling orange tree root water uptake active area by minimally invasive ERT data and transpiration measurements

NASA Astrophysics Data System (ADS)

Vanella, Daniela; Boaga, Jacopo; Perri, Maria Teresa; Consoli, Simona; Cassiani, Giorgio

2015-04-01

The comprehension of the hydrological processes involving plant root dynamics is crucial for implementing water saving measures in agriculture. This is particular urgent in areas, like those Mediterranean, characterized by scarce water availability. The study of root water dynamics should not be separated from a more general analysis of the mass and energy fluxes transferred in the soil-plant-atmosphere continuum. In our study, in order to carry this inclusive approach, minimal invasive 3D time-lapse electrical resistivity tomography (ERT) for soil moisture estimation was combined with plant transpiration fluxes directly measured with Sap Flow (SF) techniques and Eddy Covariance methods, and volumetric soil moisture measurements by TDR probes. The main objective of this inclusive approach was to accurately define root-zone water dynamics and individuate the root-area effectively active for water and nutrient uptake process. The monitoring was carried out in Eastern Sicily (south Italy) in summers 2013 and 2014, within an experimental orange orchard farm. During the first year of experiment (October 2013), ERT measurements were carried out around the pertinent volume of one fully irrigated tree, characterized by a vegetation ground cover of 70%; in the second year (June 2014), ERT monitoring was conducted considering a cutting plant, thus to evaluate soil water dynamics without the significant plant transpiration contribution. In order to explore the hydrological dynamics of the root zone volume surrounded by the monitored tree, the resistivity data acquired during the ERT monitoring were converted into soil moisture content distribution by a laboratory calibration based on the soil electrical properties as a function of moisture content and pore water electrical conductivity. By using ERT data in conjunction with the agro-meteorological information (i.e. irrigation rates, rainfall, evapotranspiration by Eddy Covariance, transpiration by Sap Flow and soil moisture content by TRD) of the test area, a spatially distributed one-dimensional (1D) model that solves the Richards' equation was applied; in the model the van Genuchten parameters were obtained by laboratory analysis of soil water retention and soil permeability at saturation. Results of the 1D model were successfully compared with both ERT-based soil moisture dynamics and TDR measurements of soil moisture. The modelling allows to defining the soil volume interested by root water uptake process and its extent. In particular, this volume results significantly smaller (i.e. surface area of 1.75 m2, with 0.4 m cm thickness) than expected, considering the design of the drip irrigation scheme adopted in the farm. The obtained results confirm that ERT is a technique that (i) can provide a lot of information on small scale and vegetation related processes; (ii) the integration with physical modelling is essential to capture the meaning of space-time signal changes; (iii) in the case of the orange orchard, this approach shows that about half of the irrigated water is wasted.

Cleaning of Root Canal System by Different Irrigation Methods.

PubMed

Tanomaru-Filho, Mário; Miano, Lucas Martinati; Chávez-Andrade, Gisselle Moraima; Torres, Fernanda Ferrari Esteves; Leonardo, Renato de Toledo; Guerreiro-Tanomaru, Juliane Maria

2015-11-01

The aim of this study was to compare the cleaning of main and lateral canals using the irrigation methods: negative pressure irrigation (EndoVac system), passive ultrasonic irrigation (PUI) and manual irrigation (MI). Resin teeth were used. After root canal preparation, four lateral canals were made at 2 and 7 mm from the apex. Root canals were filled with contrast solution and radiographed pre- and post-irrigation using digital radiographic system [radiovisiography (RVG)]. The irrigation protocols were: MI1-manual irrigation [22 G needle at 5 mm short of working length-WL]; MI2-manual irrigation (30G needle at 2 mm short of WL); PUI; EV1-EndoVac (microcannula at 1 mm short of WL); EV2-Endovac (microcannula at 3 mm short of WL). The obtained images, initial (filled with contrast solution) and final (after irrigation) were analyzed by using image tool 3.0 software. Statistical analysis was performed by analysis of variance (ANOVA) and Tukey tests (5% significance level). EV1 and EV2, followed by PUI showed better cleaning capacity than manual irrigation (MI1 and MI2) (p < 0.05). Negative pressure irrigation and PUI promoted better cleaning of main and simulated lateral canals. Conventional manual irrigation technique may promote less root canal cleaning in the apical third. For this reason, the search for other irrigation protocols is important, and EndoVac and PUI are alternatives to contribute to irrigation effectiveness.

Enhanced vadose zone nitrogen removal by poplar during dormancy.

PubMed

Ausland, Hayden; Ward, Adam; Licht, Louis; Just, Craig

2015-01-01

A pilot-scale, engineered poplar tree vadose zone system was utilized to determine effluent nitrate (NO3(-)) and ammonium concentrations resulting from intermittent dosing of a synthetic wastewater onto sandy soils at 4.5°C. The synthetic wastewater replicated that of an industrial food processor that irrigates onto sandy soils even during dormancy which can leave groundwater vulnerable to NO3(-) contamination. Data from a 21-day experiment was used to assess various Hydrus model parameterizations that simulated the impact of dormant roots. Bromide tracer data indicated that roots impacted the hydraulic properties of the packed sand by increasing effective dispersion, water content and residence time. The simulated effluent NO3(-) concentration on day 21 was 1.2 mg-N L(-1) in the rooted treatments compared to a measured value of 1.0 ± 0.72 mg-N L(-1). For the non-rooted treatment, the simulated NO3(-) concentration was 4.7 mg-N L(-1) compared to 5.1 ± 3.5 mg-N L(-1) measured on day 21. The model predicted a substantial "root benefit" toward protecting groundwater through increased denitrification in rooted treatments during a 21-day simulation with 8% of dosed nitrogen converted to N2 compared to 3.3% converted in the non-rooted test cells. Simulations at the 90-day timescale provided similar results, indicating increased denitrification in rooted treatments.

A two-plane internally irrigated root observation system for forest nursery stock.

Treesearch

Paul S. Johnson; Charles W. Putnam; William G. Mares

1981-01-01

A root observation chamber designed for forest nursery stock is described. The chamber consists of lower root observation section and a detachable upper "planter" section, both constructed of plexiglass and wood; the lower section is internally irrigated by a porous irrigation tube and the upper section by a "leader tube."

The Automated Root Exudate System (ARES): a method to apply solutes at regular intervals to soils in the field.

PubMed

Lopez-Sangil, Luis; George, Charles; Medina-Barcenas, Eduardo; Birkett, Ali J; Baxendale, Catherine; Bréchet, Laëtitia M; Estradera-Gumbau, Eduard; Sayer, Emma J

2017-09-01

Root exudation is a key component of nutrient and carbon dynamics in terrestrial ecosystems. Exudation rates vary widely by plant species and environmental conditions, but our understanding of how root exudates affect soil functioning is incomplete, in part because there are few viable methods to manipulate root exudates in situ . To address this, we devised the Automated Root Exudate System (ARES), which simulates increased root exudation by applying small amounts of labile solutes at regular intervals in the field.The ARES is a gravity-fed drip irrigation system comprising a reservoir bottle connected via a timer to a micro-hose irrigation grid covering c . 1 m 2 ; 24 drip-tips are inserted into the soil to 4-cm depth to apply solutions into the rooting zone. We installed two ARES subplots within existing litter removal and control plots in a temperate deciduous woodland. We applied either an artificial root exudate solution (RE) or a procedural control solution (CP) to each subplot for 1 min day -1 during two growing seasons. To investigate the influence of root exudation on soil carbon dynamics, we measured soil respiration monthly and soil microbial biomass at the end of each growing season.The ARES applied the solutions at a rate of c . 2 L m -2  week -1 without significantly increasing soil water content. The application of RE solution had a clear effect on soil carbon dynamics, but the response varied by litter treatment. Across two growing seasons, soil respiration was 25% higher in RE compared to CP subplots in the litter removal treatment, but not in the control plots. By contrast, we observed a significant increase in microbial biomass carbon (33%) and nitrogen (26%) in RE subplots in the control litter treatment.The ARES is an effective, low-cost method to apply experimental solutions directly into the rooting zone in the field. The installation of the systems entails minimal disturbance to the soil and little maintenance is required. Although we used ARES to apply root exudate solution, the method can be used to apply many other treatments involving solute inputs at regular intervals in a wide range of ecosystems.

Impact assessment and recommendation of alternative conjunctive water use strategies for salt affected agricultural lands through a field scale decision support system - a case study.

PubMed

Kaur, Ravinder; Paul, Madhumita; Malik, Rashmi

2007-06-01

Conjunctive use of saline/non-saline irrigation waters is generally aimed at minimizing yield losses and enhancing flexibility of cropping, without much alteration in farming operations. Recommendation of location-specific suitable conjunctive water use plans requires assessment of their long-term impacts on soil salinization/sodification and crop yield reductions. This is conventionally achieved through long-term field experiments. However such impact evaluations are site specific, expensive and time consuming. Appropriate decision support systems (DSS) can be time-efficient and cost-effective means for such long-term impact evaluations. This study demonstrates the application of one such (indigenously developed) DSS for recommending best conjunctive water use plans for a, rice-wheat growing, salt affected farmer's field in Gurgaon district of Haryana (India). Before application, the DSS was extensively validated on several farmers and controlled experimental fields in Gurgaon and Karnal districts of Haryana (India). Validation of DSS showed its potential to give realistic estimates of root zone soil salinity (with R = 0.76-0.94; AMRE = 0.03-0.06; RMSPD = 0.51-0.90); sodicity (with R = 0.99; AMRE = 0.02; RMSPD = 0.84) and relative crop yield reductions (AMRE = 0.24), under existing (local) resource management practices. Long term (10 years) root zone salt build ups and associated rice/wheat crop yield reductions, in a salt affected farmer's field, under varied conjunctive water use scenarios were evaluated with the validated DSS. It was observed that long-term applications of canal (CW) and tube well (TW) waters in a cycle and in 1:1 mixed mode, during Kharif season, predicted higher average root zone salt reductions (2-9%) and lower rice crop yield reductions (4-5%) than the existing practice of 3-CW, 3-TW, 3-CW. Besides this, long-term application of 75% CW mixed with 25% TW, during Rabi season, predicted about 17% lower average root-zone salt reductions than the cyclic applications of (1-CW, 1-TW, 2-CW) and (2-CW, 1-TW, 1-CW, i.e., existing irrigation strategy). However, average wheat crop yield reductions (16-17%) simulated under all these strategies were almost at par. In general, cyclic-conjunctive water use strategies emerged as better options than the blending modes. These results were in complete confirmation with actual long-term conjunctive water use experiments on similar soils. It was thus observed that such pre-validated tools could be efficient means for designing, local resource and target crop yield-specific, appropriate conjunctive water use plans for irrigated agricultural lands.

Predicting deep percolation with eddy covariance under mulch drip irrigation

NASA Astrophysics Data System (ADS)

Ming, Guanghui; Tian, Fuqiang; Hu, Hongchang

2016-04-01

Water is essential for the agricultural development and ecological sustainability of the arid and semi-arid oasis with rare precipitation input and high evaporation demand. Deep percolation (DP) defined as excess irrigation water percolating below the plant root zone will reduce irrigation water use efficiency (WUE). But the DP was often ignored in mulch drip irrigation (MDI) which has reached the area of 1.6 million hectares in Xinjiang, the northwest of China. In this study DP experiments were conducted at an agricultural experiment station located within an irrigation district in the Tarim River Basin for four cotton growing periods. First it was detected the irrigation water infiltrated into the soil layers below 100cm and the groundwater level responded to the irrigation events well. Then DP below 100cm soil layers was calculated using the soil water balance method with the aid of eddy covariance (with the energy balance closure of 0.72). The negative DP (groundwater contribution to the crop-water use through capillary rising) at the seedling and harvesting stages can reach 77mm and has a good negative correlation with the groundwater level and positive correlation with potential evaporation. During the drip irrigation stage approximately 45% of the irrigation became DP and resulted in the low irrigation WUE of 0.6. The DP can be 164mm to 270mm per year which was positive linearly correlated to irrigation depth and negative linear correlated to irrigation interval. It is better to establish the irrigation schedule with small irrigation depth and given frequently to reduce deep percolation and meet crop needs.

Water saving at the field scale with Irrig-OH, an open-hardware environment device for soil water potential monitoring and irrigation management

NASA Astrophysics Data System (ADS)

Masseroni, Daniele; Facchi, Arianna; Gandolfi, Claudio

2015-04-01

Sustainability of irrigation practices is an important objective which should be pursued in many countries, especially in areas where water scarcity causes strong conflicts among the different water uses. The efficient use of water is a key factor in coping with the food demand of an increasing world population and with the negative effects of the climate change on water resources availability in many areas. In this complex context, it is important that farmers adopt instruments and practices that enable a better management of water at the field scale, whatever the irrigation method they adopt. This work presents the hardware structure and the functioning of an open-hardware microstation based on the Arduino technology, called Irrig-OH, which allows the continuous and low-cost monitoring of the soil water potential (SWP) in the root zone for supporting the irrigation scheduling at the field scale. In order to test the microstation, an experiment was carried out during the agricultural season 2014 at Lodi (Italy), with the purpose of comparing the farmers' traditional management of irrigation of a peach variety and the scheduling based on the SWP measurements provided by the microstation. Additional measurements of leaf water potential (LWP), stomatal resistance, transpiration (T), crop water stress index (CWSI) and fruit size evolution were performed respectively on leafs and fruits for verifying the plant physiological responses on different SWP levels in soil. At the harvesting time, the peach production in term of quantity and quality (sucrose content was measured by a rifractometer over a sample of one hundred fruits) of the two rows were compared. Irrigation criteria was changed with respect to three macro-periods: up to the endocarp hardening phase (begin of May) soil was kept well watered fixing the SWP threshold in the first 35 cm of the soil profile at -20 kPa, during the pit hardening period (about the entire month of May) the allowed SWP threshold was -30 kPa and, finally, from the end of May to the harvesting time (maturation process), irrigation was applied when SWP reached -25 kPa. Every time irrigation events were stopped when SWP at the field capacity (-10 kPa) was restored in the upper part of the root zone. Results showed a water saving of nearly 50% using the Irrig-OH device, without consequences on the quantity and quality of the production. Plant physiological status based on LWP, T and CWSI measurements showed that despite the different irrigation treatments adopted, no considerable plant stress was found in both rows. In particular, maximum values of the previous indices, performed at midday, were respectively -2 MPa, 1.4 mm h-1 and 0.6, which were in good agreement with those observed by many researches for no-stressed peach orchards in Mediterranean areas.

Comparison of the antibacterial efficiency of neem leaf extracts, grape seed extracts and 3% sodium hypochlorite against E. feacalis – An in vitro study

PubMed Central

Ghonmode, Wasudeo Namdeo; Balsaraf, Omkar D; Tambe, Varsha H; Saujanya, K P; Patil, Ashishkumar K; Kakde, Deepak D

2013-01-01

Background: E. faecalis is the predominant micro-organism recovered from root canal of the teeth where previous endodontic treatment has failed. Thorough debridement and complete elimination of micro-organisms are objectives of an effective endodontic treatment. For many years, intracanal irrigants have been used as an adjunct to enhance antimicrobial effect of cleaning and shaping in endodontics. The constant increase in antibiotic-resistant strains and side-effects of synthetic drugs has promoted researchers to look for herbal alternatives. For thousands of years humans have sought to fortify their health and cure various illnesses with herbal remedies, but only few have been tried and tested to withstand modern scientific scrutiny. The present study was aimed to evaluate alternative, inexpensive simple and effective means of sanitization of the root canal systems. The antimicrobial efficacy of herbal alternatives as endodontic irrigants is evaluated and compared with the standard irrigant sodium hypochlorite. Materials & Methods: Neem leaf extracts, grape seed extracts, 3% Sodium hypochlorite, absolute ethanol, Enterococcus faecalis (ATCC 29212) cultures, Brain heart infusion media. The agar diffusion test was performed in brain heart infusion media and broth. The agar diffusion test was used to measure the zone of inhibition. Results: Neem leaf extracts and grape seed extracts showed zones of inhibition suggesting that they had anti-microbial properties. Neem leaf extracts showed significantly greater zones of inhibition than 3% sodium hypochlorite. Also interestingly grape seed extracts showed zones of inhibition but were not as significant as of neem extracts. Conclusion: Under the limitations of this study, it was concluded that neem leaf extract has a significant antimicrobial effect against E. faecalis. Microbial inhibition potential of neem leaf extract observed in this study opens perspectives for its use as an intracanal medication. How to cite this article: Ghonmode WN, Balsaraf OD, Tambe VH, Saujanya KP, Patil AK, Kakde DD. Comparison of the antibacterial efficiency of neem leaf extracts, grape seed extracts and 3% sodium hypochlorite against E. feacalis – An in vitro study. J Int Oral Health 2013; 5(6):61-6 . PMID:24453446

Irrigation Differentially Impacts Populations of Indigenous Antibiotic-Producing Pseudomonas spp. in the Rhizosphere of Wheat

PubMed Central

Mavrodi, Olga V.; Mavrodi, Dmitri V.; Parejko, James A.; Thomashow, Linda S.

2012-01-01

This work determined the impact of irrigation on the seasonal dynamics of populations of Pseudomonas spp. producing the antibiotics phenazine-1-carboxylic acid (Phz+) and 2,4-diacetylphloroglucinol (Phl+) in the rhizosphere of wheat grown in the low-precipitation zone (150 to 300 mm annually) of the Columbia Plateau of the Inland Pacific Northwest. Population sizes and plant colonization frequencies of Phz+ and Phl+ Pseudomonas spp. were determined in winter and spring wheat collected during the growing seasons from 2008 to 2009 from selected commercial dryland and irrigated fields in central Washington State. Only Phz+ bacteria were detected on dryland winter wheat, with populations ranging from 4.8 to 6.3 log CFU g−1 of root and rhizosphere colonization frequencies of 67 to 100%. The ranges of population densities of Phl+ and Phz+ Pseudomonas spp. recovered from wheat grown under irrigation were similar, but 58 to 100% of root systems were colonized by Phl+ bacteria whereas only 8 to 50% of plants harbored Phz+ bacteria. In addition, Phz+ Pseudomonas spp. were abundant in the rhizosphere of native plant species growing in nonirrigated areas adjacent to the sampled dryland wheat fields. This is the first report that documents the impact of irrigation on indigenous populations of two closely related groups of antibiotic-producing pseudomonads that coinhabit the rhizosphere of an economically important cereal crop. These results demonstrate how crop management practices can influence indigenous populations of antibiotic-producing pseudomonads with the capacity to suppress soilborne diseases of wheat. PMID:22389379

Deficit irrigation of a landscape halophyte for reuse of saline waste water in a desert city

USGS Publications Warehouse

Glenn, E.P.; Mckeon, C.; Gerhart, V.; Nagler, P.L.; Jordan, F.; Artiola, J.

2009-01-01

Saline waste waters from industrial and water treatment processes are an under-utilized resource in desert urban environments. Management practices to safely use these water sources are still in development. We used a deeprooted native halophyte, Atriplex lentiformis (quailbush), to absorb mildly saline effluent (1800 mg l-1 total dissolved solids, mainly sodium sulfate) from a water treatment plant in the desert community of Twentynine Palms, California. We developed a deficit irrigation strategy to avoid discharging water past the root zone to the aquifer. The plants were irrigated at about one-third the rate of reference evapotranspiration (ETo) calculated from meteorological data over five years and soil moisture levels were monitored to a soil depth of 4.7 m at monthly intervals with a neutron hydroprobe. The deficit irrigation schedule maintained the soil below field capacity throughout the study. Water was presented on a more or less constant schedule, so that the application rates were less than ETo in summer and equal to or slightly greater than ETo in winter, but the plants were able to consume water stored in the profile in winter to support summer ET. Sodium salts gradually increased in the soil profile over the study but sulfate levels remained low, due to formation of gypsum in the calcic soil. The high salt tolerance, deep roots, and drought tolerance of desert halophytes such as A. lentiformis lend these plants to use as deficit-irrigated landscape plants for disposal of effluents in urban setting when protection of the aquifer is important. ?? 2008 Elsevier B.V.

Salinity management using an anionic polymer in a pecan field with calcareous-sodic soil.

PubMed

Ganjegunte, Girisha K; Sheng, Zhuping; Braun, Robert J

2011-01-01

Soil salinity and sodicity have long been recognized as the major concerns for irrigated agriculture in the Trans-Pecos Basin, where fields are being flood irrigated with Rio Grande River water that has elevated salinity. Reclamation of these salt-affected lands is difficult due to fine-texture, high shrink-swell soils with low permeability. Conventional practice of subsoiling to improve soil permeability is expensive and has had limited success on the irrigated soils that have appreciable amounts of readily weatherable Ca minerals. If these native Ca sources can be effectively used to counter sodicity, it can improve soil permeability and reduce amelioration costs. This study evaluated the effects of 3 yr of polyacrylamide (PAM) application at 10 mg L concentration during the first irrigation of the season to evaluate soil permeability, in situ Ca mineral dissolution, and leaching of salts from the effective root zone in a pecan field of El Paso County, TX. Results indicated that PAM application improved water movement throughout the effective root zone that resulted in Na leaching. Polymer application significantly decreased CaCO (estimated based on inorganic C analysis) concentrations in the top 45 cm compared with baseline levels, indicating solubilization and redistribution of calcite. The PAM application also reduced soil electrical conductivity (EC) in the top 60 cm (4.64-2.76 dS m) and sodium adsorption ratio (SAR) from 13.1 to 5.7 mmol L in the top 75-cm depths. As evidence of improved soil conditions, pecan nut yields increased by 34% in PAM-treated fields over the control. Results suggested that PAM application helped in effective use of native Ca sources present in soils of the study site and reduced Na by improving soil permeability. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Complication of improper management of sodium hypochlorite accident during root canal treatment

PubMed Central

Faras, Fatemah; Abo-Alhassan, Fawaz; Sadeq, Abdullah; Burezq, Hisham

2016-01-01

Sodium Hypochlorite (NaOCl) is a common irrigation solution used in root canal treatment. It has strong antibacterial and tissue dissolving properties. Nevertheless, it has some serious complications, some of which are life-threatening. A young male presented with severe chemical burn of the right infraorbital area and partial necrosis of the hard palate resulting from extrusion of NaOCl during root canal treatment of the upper right 2nd molar tooth. The patient had a facial scar, and mucosal damage healed nearly completely. Several precautions must be taken during NaOCl use to prevent the spread of the solution into surrounding tissues. Early recognition of NaOCl accident and proper immediate management are important to achieve the best possible outcome. PMID:27891318

In vivo antimicrobial efficacy of 6% Morinda citrifolia, Azadirachta indica, and 3% sodium hypochlorite as root canal irrigants.

PubMed

Podar, Rajesh; Kulkarni, Gaurav P; Dadu, Shifali S; Singh, Shraddha; Singh, Shishir H

2015-01-01

To evaluate and compare the antimicrobial efficacy of 6% Morinda citrifolia, Azadirachta indica, and 3% sodium hypochlorite (NaOCl) as root canal irrigants. Thirty nonvital maxillary anteriors were randomly assigned to one of the three groups corresponding to the irrigant to be tested; 6% Morinda citrifolia juice (MCJ) (n = 10), A. indica (n = 10) and 3% NaOCl (n = 10). After the root canal access opening a root canal culture sample was taken with two paper points and cultured under aerobic and anaerobic conditions. Cleaning and shaping were completed with irrigation by 10 mL of respective irrigants and 5 mL of final rinse. The patients were recalled after 3 days and canals were rinsed again with 5 mL of the test irrigants. This was followed by obtaining a posttreatment root canal culture sample and culturing and analyzed by counting the colony forming units (CFUs). Six percentage MCJ, A. indica, and 3% NaOCl showed a significant reduction (P < 0.05) in the mean CFU counts for aerobic and anaerobic bacteria between baseline and 3 days. There was no difference in the antimicrobial efficacy of 6% M. citrifolia, A. indica, and 3% NaOCl as root canal irrigants.

Nitrogen fluxes through unsaturated zones in five agricultural settings across the United States

USGS Publications Warehouse

Green, C.T.; Fisher, L.H.; Bekins, B.A.

2008-01-01

The main physical and chemical controls on nitrogen (N) fluxes between the root zone and the water table were determined for agricultural sites in California, Indiana, Maryland, Nebraska, and Washington from 2004 to 2005. Sites included irrigated and nonirrigated fields; soil textures ranging from clay to sand; crops including corn, soybeans, almonds, and pasture; and unsaturated zone thicknesses ranging from 1 to 22 m. Chemical analyses of water from lysimeters and shallow wells indicate that advective transport of nitrate is the dominant process affecting the flux of N below the root zone. Vertical profiles of (i) nitrogen species, (ii) stable isotopes of nitrogen and oxygen, and (iii) oxygen, N, and argon in unsaturated zone air and correlations between N and other agricultural chemicals indicate that reactions do not greatly affect N concentrations between the root zone and the capillary fringe. As a result, physical factors, such as N application rate, water inputs, and evapotranspiration, control the differences in concentrations among the sites. Concentrations of N in shallow lysimeters exhibit seasonal variation, whereas concentrations in lysimeters deeper than a few meters are relatively stable. Based on concentration and recharge estimates, fluxes of N through the deep unsaturated zone range from 7 to 99 kg ha-1 yr-1. Vertical fluxes of N in ground water are lower due to spatial and historical changes in N inputs. High N fluxes are associated with coarse sediments and high N application rates. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

[Influence of different ultrasonic irrigation solutions after root canal preparation with ProTaper by machine on micro-hardness of root canal dentin].

PubMed

Guo, Jiang-li; Zhang, Yan; Zhen, Lei

2015-08-01

To develope the influence of different ultrasonic irrigations after root canal preparation with nickel titanium ProTaper on micro-hardness of root canal dentin. Sixty of maxillary anterior teeth with single-canal were collected and randomly divided into 6 groups. Group A was control group, group B was prepared to F3 with nickel titanium ProTaper by machine, group C was ultrasonic irrigated with 3% hydrogen peroxide solution for 1 minute after preparation, group D was ultrasonic irrigated with koutai mouthwash for 1 minute after preparation, group E was ultrasonic irrigated with 17% EDTA solution for 1 minute after preparation, group F was ultrasonic irrigated with distilled water for 1 minute after preparation. The roots were then sectioned horizontally into 3 parts, split longitudinally into halves and examined under a micro Vickers hardness test machine. The data was analyzed by one-way ANOVA and t test with SPSS 17.0 software package. The micro-hardness of group A was (52.66 ± 1.64) HV,(52.08 ± 1.53) HV and (51.47 ± 2.53) HV. There was no significant difference in all parts of the root canal in group A (P>0.05). The micro-hardness of the apical third of root canal was lower than that of the cervical and middle of root canal in the other groups (P<0.05). In the cervical and middle third of the root canals, the micro-hardness of group E was (44.65 ± 1.33) HV and(42.55 ± 1.12) HV, and there were statistical significances between group E and the other groups (P<0.05). In the apical third of root canal,the micro-hardness of group E was (37.82 ± 1.60) HV, and group C was (44.14±1.73) HV, both of the comparative differences with other groups were statistically significant (P<0.05). There was no significant difference among group B, group D and group F (P>0.05). Root canal preparation to F3 with nickel titanium ProTaper by machine can make the micro-hardness of the apical third of root canal decrease. Ultrasonic irrigation with 17% EDTA solution for 1 minute can make the micro-hardness of the root canal decrease ultrasonic irrigation with. Ultrasonic irrigation with 3% hydrogen peroxide can make the micro-hardness of the apical third of root canal decrease. Ultrasonic irrigation with Koutai mouthwash and distilled water for 1 minute have no influence on the micro-hardness of root canal.

Efficiency of Different Endodontic Irrigation and Activation Systems in Removal of the Smear Layer: A Scanning Electron Microscopy Study.

PubMed

Karade, Priyatam; Chopade, Rutuja; Patil, Suvarna; Hoshing, Upendra; Rao, Madhukar; Rane, Neha; Chopade, Aditi; Kulkarni, Anish

2017-01-01

This in vitro study was designed to evaluate and compare different endodontic irrigation and activation systems for removal of the intracanal smear layer. Forty recently extracted, non-carious human intact single rooted premolars were selected and divided into five groups ( n =10) according to the root canal irrigation systems; syringe and needle irrigation (CTR), sonic irrigation, passive ultrasonic irrigation (PUI) and EndoVac irrigation system. All groups were prepared to #40 apical size with K-files. Each sample was subjected to final irrigation by using four different irrigation/activation systems. After splitting the samples, one half of each root was selected for examination under scanning electron microscope (SEM). The irrigation systems were compared using the Fisher's exact test with the level of significance set at 0.05. The four groups did not differ from each other in the coronal and mid-root parts of the canal. In the apical part of the canal none of the methods could completely remove all the smear layer but EndoVac system showed significantly better removal of smear layer and debris than the other methods. Within the limitations of the present study, the EndoVac system cleaned the apical part of the canal more efficiently than sonic, ultrasonic and syringe and needle irrigation.

Effectiveness of various irrigation activation protocols and the self-adjusting file system on smear layer and debris removal.

PubMed

Çapar, İsmail Davut; Aydinbelge, Hale Ari

2014-01-01

The purpose of the present study is to evaluate smear layer generation and residual debris after using self-adjusting file (SAF) or rotary instrumentation and to compare the debris and smear layer removal efficacy of the SAF cleaning/shaping irrigation system against final agitation techniques. One hundred and eight maxillary lateral incisor teeth were randomly divided into nine experimental groups (n = 12), and root canals were prepared using ProTaper Universal rotary files, with the exception of the SAF instrumentation group. During instrumentation, root canals were irrigated with a total of 16 mL of 5% NaOCl. For final irrigation, rotary-instrumented groups were irrigated with 10 mL of 17% EDTA and 10 mL of 5% NaOCl using different irrigation agitation regimens (syringe irrigation with needles, NaviTip FX, manual dynamic irrigation, CanalBrush, EndoActivator, EndoVac, passive ultrasonic irrigation (PUI), and SAF irrigation). In the SAF instrumentation group, root canals were instrumented for 4 min at a rate of 4 mL/min with 5% NaOCl and received a final flush with same as syringe irrigation with needles. The surface of the root dentin was observed using a scanning electron microscope. The SAF instrumentation group generated less smear layer and yielded cleaner canals compared to rotary instrumentation. The EndoActivator, EndoVac, PUI, and SAF irrigation groups increased the efficacy of irrigating solutions on the smear layer and debris removal. The SAF instrumentation yielded cleaner canal walls when compared to rotary instrumentation. None of the techniques completely removed the smear layer from the root canal walls. © 2014 Wiley Periodicals, Inc.

Evaluation of 4% Sodium Hypochlorite in eliminating Enterococcus faecalis from the Root Canal when Used with Three Irrigation Methods: An in vitro Study.

PubMed

Priyank, Harsh; Pandey, Vinisha; Bagul, Abhishek; Majety, Kishore Kumar; Verma, Parul; Choudhury, Basanta Kumar

2017-03-01

Endodontic treatment removes all pathogens, such as Enterococcus faecalis from pulp and root canals. The aim of this study is to assess the usefulness of sodium hypo-chlorite (NaOCl) in removing E. faecalis from the root canal used with three different irrigation methods. This study was conducted on freshly extracted maxillary incisors. After biomechanical preparation, root canals were injected with E. faecalis. Three groups were made which contained 30 teeth in each group; 2 mL of NaOCl solution was used for irrigation followed by agitation with K-files in group I; 2 mL of NaOCl solution was used for irrigation and ultrasonic agitation was done in group II. In group III, an alternate irrigation with NaOCl and 3% hydrogen peroxide was done. The fourth group (control) was irrigated with sterile saline solution. E. fae-calis bacteria were sampled to the root canals with paper points and were transferred to tubes that contained 5 mL of brain heart infusion broth. Tubes were incubated and the presence of broth turbidity was suggestive of bacteria remaining in the root canal. All three groups showed no statistically significant difference. However, difference existed between experimental groups and control groups. The author concluded that all three methods of application of NaOCl were effective in disinfecting the root canal than the saline solution. No single irrigant has 100% efficiency. Thus by this study, a best irrigating solution with maximum properties can be established.

Salt and N leaching and soil accumulation due to cover cropping practices

NASA Astrophysics Data System (ADS)

Gabriel, J. L.; Quemada, M.

2012-04-01

Nitrate leaching beyond the root zone can increase water contamination hazards and decrease crop available N. Cover crops used in spite of fallow are an alternative to reduce nitrate contamination in the vadose zone, because reducing drainage and soil mineral N accumulation. Cover crops can improve important characteristics in irrigated land as water retention capacity or soil aggregate stability. However, increasing evapotranspiration and consequent drainage below the root system reduction, could lead to soil salt accumulation. Salinity affects more than 80 million ha of arable land in many areas of the world, and one of the principal causes for yield reduction and even land degradation in the Mediterranean region. Few studies dealt with both problems at the same time. Therefore, it is necessary a long-term evaluation of the potential effect on soil salinity and nitrate leaching, in order to ensure that potential disadvantages that could originate from soil salt accumulation are compensated with all advantages of cover cropping. A study of the soil salinity and nitrate leaching was conducted during 4 years in a semiarid irrigated agricultural area of Central Spain. Three treatments were studied during the intercropping period of maize (Zea mays L.): barley (Hordeum vulgare L.), vetch (Vicia villosa L.) and fallow. Cover crops were killed in March allowing seeding of maize of the entire trial in April, and all treatments were irrigated and fertilised following the same procedure. Before sowing, and after harvesting maize and cover crops, soil salt and nitrate accumulation was determined along the soil profile. Soil analysis was conducted at six depths every 0.20 m in each plot in samples from four 0 to 1.2-m depth holes dug. The electrical conductivity of the saturated paste extract and soil mineral nitrogen was measured in each soil sample. A numerical model based on the Richards water balance equation was applied in order to calculate drainage at 1.2 m depth, using daily soil water content measurements, based on calibrated capacitance probes. Our results showed that drainage during the irrigated period was minimized, because irrigation water was adjusted to crop needs, leading to soil salt and nitrate accumulation on the upper layers after maize harvest. Then, during the intercrop period, most of salt and nitrate leaching occurred. Cover crops use led to shorter drainage period, lower drainage water amount and lower nitrate and salt leaching than treatment with fallow. These effects were related with a larger nitrate accumulation in the upper layers of the soil after cover crop treatments. But there was not soil salt accumulation increase in treatments with cover crops, and even decreased after years with a large cover crop biomass production. Then, adoption of cover crops in this kind of irrigated cropping system reduced water drainage beyond the root zone, salt and nitrate leaching diminished as a consequence but did not lead to salt accumulation in the upper soil layers. Acknowledgements: Financial support by CICYT, Spain (ref. AGL2005-00163 and AGL 2011-24732) and Comunidad de Madrid (project AGRISOST, S2009/AGR-1630).

Simultaneous effects of leaf irradiance and soil moisture on growth and root system architecture of novel wheat genotypes: implications for phenotyping

PubMed Central

Nagel, Kerstin A.; Bonnett, David; Furbank, Robert; Walter, Achim; Schurr, Ulrich; Watt, Michelle

2015-01-01

Plants in the field are exposed to varying light and moisture. Agronomic improvement requires knowledge of whole-plant phenotypes expressed in response to simultaneous variation in these essential resources. Most phenotypes, however, have been described from experiments where resources are varied singularly. To test the importance of varying shoot and root resources for phenotyping studies, sister pre-breeding lines of wheat were phenotyped in response to independent or simultaneous exposure to two light levels and soil moisture profiles. The distribution and architecture of the root systems depended strongly on the moisture of the deeper soil layer. For one genotype, roots, specifically lateral roots, were stimulated to grow into moist soil when the upper zone was well-watered and were inhibited by drier deep zones. In contrast, the other genotype showed much less plasticity and responsiveness to upper moist soil, but maintained deeper penetration of roots into the dry layer. The sum of shoot and root responses was greater when treated simultaneously to low light and low soil water, compared to each treatment alone, suggesting the value of whole plant phenotyping in response to multiple conditions for agronomic improvement. The results suggest that canopy management for increased irradiation of leaves would encourage root growth into deeper drier soil, and that genetic variation within closely related breeding lines may exist to favour surface root growth in response to irrigation or in-season rainfall. PMID:26089535

Preparation Prerequisites for Effective Irrigation of Apical Root Canal: A Critical Review.

PubMed

Tziafas, Dimitrios; Alraeesi, Dana; Al Hormoodi, Reem; Ataya, Maamoun; Fezai, Hessa; Aga, Nausheen

2017-10-01

It is well recognized that disinfection of the complex root canal system at the apical root canal remains the most critical therapeutic measure to treat apical periodontitis. Observational and experimental data in relation to the anatomy of the apical root canal in different tooth types and the cross sectional diameters of the apical part of the most commonly used hand and rotary files are critically reviewed. The present data analysis confirm that the challenging issue of antibacterial efficacy of modern preparation protocols in non-surgical endodontics requires more attention to apical root canal irrigation as a balance between safety and effectiveness. Ex vivo investigations clearly indicate that a specific design of the chemo-mechanical preparation is needed at the onset of RCT, more particularly in infected teeth. Design should be based on specific anatomical parameters, and must determine the appropriate size and taper of preparation as pre-requirements for effective and safe apical irrigation. The optimal irrigation protocols might be designed on the basis of technical specifications of the preparations procedures, such as the penetration depth, the type of the needle, the required time for continuous irrigant flow, the concentration of NaOCl, and the activation parameters. Key words: Endodontics, root canal treatment, instrumentation, irrigation, apical root canal.

Local root abscisic acid (ABA) accumulation depends on the spatial distribution of soil moisture in potato: implications for ABA signalling under heterogeneous soil drying

PubMed Central

Puértolas, Jaime; Conesa, María R.; Ballester, Carlos; Dodd, Ian C.

2015-01-01

Patterns of root abscisic acid (ABA) accumulation ([ABA]root), root water potential (Ψroot), and root water uptake (RWU), and their impact on xylem sap ABA concentration ([X-ABA]) were measured under vertical partial root-zone drying (VPRD, upper compartment dry, lower compartment wet) and horizontal partial root-zone drying (HPRD, two lateral compartments: one dry, the other wet) of potato (Solanum tuberosum L.). When water was withheld from the dry compartment for 0–10 d, RWU and Ψroot were similarly lower in the dry compartment when soil volumetric water content dropped below 0.22cm3 cm–3 for both spatial distributions of soil moisture. However, [ABA]root increased in response to decreasing Ψroot in the dry compartment only for HPRD, resulting in much higher ABA accumulation than in VPRD. The position of the sampled roots (~4cm closer to the surface in the dry compartment of VPRD than in HPRD) might account for this difference, since older (upper) roots may accumulate less ABA in response to decreased Ψroot than younger (deeper) roots. This would explain differences in root ABA accumulation patterns under vertical and horizontal soil moisture gradients reported in the literature. In our experiment, these differences in root ABA accumulation did not influence [X-ABA], since the RWU fraction (and thus ABA export to shoots) from the dry compartment dramatically decreased simultaneously with any increase in [ABA]root. Thus, HPRD might better trigger a long-distance ABA signal than VPRD under conditions allowing simultaneous high [ABA]root and relatively high RWU fraction. PMID:25547916

Local root abscisic acid (ABA) accumulation depends on the spatial distribution of soil moisture in potato: implications for ABA signalling under heterogeneous soil drying.

PubMed

Puértolas, Jaime; Conesa, María R; Ballester, Carlos; Dodd, Ian C

2015-04-01

Patterns of root abscisic acid (ABA) accumulation ([ABA]root), root water potential (Ψroot), and root water uptake (RWU), and their impact on xylem sap ABA concentration ([X-ABA]) were measured under vertical partial root-zone drying (VPRD, upper compartment dry, lower compartment wet) and horizontal partial root-zone drying (HPRD, two lateral compartments: one dry, the other wet) of potato (Solanum tuberosum L.). When water was withheld from the dry compartment for 0-10 d, RWU and Ψroot were similarly lower in the dry compartment when soil volumetric water content dropped below 0.22cm(3) cm(-3) for both spatial distributions of soil moisture. However, [ABA]root increased in response to decreasing Ψroot in the dry compartment only for HPRD, resulting in much higher ABA accumulation than in VPRD. The position of the sampled roots (~4cm closer to the surface in the dry compartment of VPRD than in HPRD) might account for this difference, since older (upper) roots may accumulate less ABA in response to decreased Ψroot than younger (deeper) roots. This would explain differences in root ABA accumulation patterns under vertical and horizontal soil moisture gradients reported in the literature. In our experiment, these differences in root ABA accumulation did not influence [X-ABA], since the RWU fraction (and thus ABA export to shoots) from the dry compartment dramatically decreased simultaneously with any increase in [ABA]root. Thus, HPRD might better trigger a long-distance ABA signal than VPRD under conditions allowing simultaneous high [ABA]root and relatively high RWU fraction. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Improving Agricultural Water Resources Management Using Ground-based Infrared Thermometry

NASA Astrophysics Data System (ADS)

Taghvaeian, S.

2014-12-01

Irrigated agriculture is the largest user of freshwater resources in arid/semi-arid parts of the world. Meeting rapidly growing demands in food, feed, fiber, and fuel while minimizing environmental pollution under a changing climate requires significant improvements in agricultural water management and irrigation scheduling. Although recent advances in remote sensing techniques and hydrological modeling has provided valuable information on agricultural water resources and their management, real improvements will only occur if farmers, the decision makers on the ground, are provided with simple, affordable, and practical tools to schedule irrigation events. This presentation reviews efforts in developing methods based on ground-based infrared thermometry and thermography for day-to-day management of irrigation systems. The results of research studies conducted in Colorado and Oklahoma show that ground-based remote sensing methods can be used effectively in quantifying water stress and consequently triggering irrigation events. Crop water use estimates based on stress indices have also showed to be in good agreement with estimates based on other methods (e.g. surface energy balance, root zone soil water balance, etc.). Major challenges toward the adoption of this approach by agricultural producers include the reduced accuracy under cloudy and humid conditions and its inability to forecast irrigation date, which is a critical knowledge since many irrigators need to decide about irrigations a few days in advance.

Decalcifying capability of irrigating solutions on root canal dentin mineral content

PubMed Central

Poggio, Claudio; Dagna, Alberto; Vinci, Andrea; Beltrami, Riccardo; Cucca, Lucia; Giardino, Luciano

2015-01-01

Background: Chelating agents are believed to aid root canal irrigation and to be able to remove the inorganic smear layer. Aims: The purpose of the present study was to evaluate and to compare the decalcifying capability of different irrigating solutions (Tubuliclean, Largal Ultra, ethylenediaminetetraacetic acid 17%, Tetraclean, Tetraclean NA). Materials and Methods: Sixty maxillary central incisors were used. Root canals were instrumented and irrigated. From each root, four comparable slices of cervical dentin were obtained. At three successive 5-min interval immersion times, the concentration of calcium extracted from root canal dentin was assessed with an inductively coupled plasma-atomic emission spectrometer. Statistical Analysis Used: Data were analyzed by means of Kruskal Wallis and Mann–Whitney tests. Significance was predetermined at P < 0.05. Results and Conclusions: For all irrigating solutions, the maximum amount of Ca2+ extracted from root canal dentin samples was reached after 10 min contact time except for citric acid-based agents (Tetraclean and Tetraclean NA) which induced a higher and still increasing calcium release even after 10 min contact time. In order to obtain an efficient decalcifying action on dentin and to facilitate the biomechanical procedures, citric acid-based irrigants can be applied. PMID:26097355

An in vitro evaluation of the degree of pulp tissue dissolution through different root canal irrigation protocols.

PubMed

Amato, Massimo; Pantaleo, Giuseppe; Abtellatif, Dina; Blasi, Andrea; Gagliani, Massimo; Iandolo, Alfredo

2018-01-01

The aim of this study is to evaluate in vitro , using artificial lateral canals, the rate of dissolution of the pulp tissue through different protocols of canal irrigation. One hundred artificial canals provided with lateral canals have been used. Each lateral canal was filled with pulp tissue and calibrated to 0.002 mg. All canals were irrigated using five different protocols. Five groups have been used for the experiment: Group A, distilled water (control); Group B, preheated NaOCl; Group C, NaOCl heated inside the canal; Group D, NaOCl ultrasonically activated; and Group E, NaOCl heated inside the canal with ultrasonic activation. All samples were weighed through professional microbalance in three different phases: before insertion of the pulp tissue into the lateral canal, after insertion of the pulp tissue and, finally, after different protocols of irrigation. A statistical analysis with Kruskal-Wallis test and Mann-Whitney test was performed. The partial dissolution of the pulp tissue inside the artificial lateral canal occurs only using the protocol with NaOCl heated inside the canal with ultrasonic activation. Other irrigation protocols are not able to dissolve the pulp tissue. The main objective of endodontic therapy is the removal of damaged tissues and bacteria. Modern literature highlights that it is impossible to remove all the pulp tissues and bacteria from the whole endodontic space. Hence, to achieve excellence and get positive results in the short and long term, it is necessary to use techniques and technologies that may increase the degree of root canal detersion.

Field tracer investigation of unsaturated zone flow paths and mechanisms in agricultural soils of northwestern Mississippi, USA

USGS Publications Warehouse

Perkins, K.S.; Nimmo, J.R.; Rose, C.E.; Coupe, R.H.

2011-01-01

In many farmed areas, intensive application of agricultural chemicals and withdrawal of groundwater for irrigation have led to water quality and supply issues. Unsaturated-zone processes, including preferential flow, play a major role in these effects but are not well understood. In the Bogue Phalia basin, an intensely agricultural area in the Delta region of northwestern Mississippi, the fine-textured soils often exhibit surface ponding and runoff after irrigation and rainfall as well as extensive surface cracking during prolonged dry periods. Fields are typically land-formed to promote surface flow into drainage ditches and streams that feed into larger river ecosystems. Downward flow of water below the root zone is considered minimal; regional groundwater models predict only 5% or less of precipitation recharges the heavily used alluvial aquifer. In this study transport mechanisms within and below the root zone of a fallow soybean field were assessed by performing a 2-m ring infiltration test with tracers and subsurface monitoring instruments. Seven months after tracer application, 48 continuous cores were collected for tracer extraction to define the extent of water movement and quantify preferential flow using a mass-balance approach. Vertical water movement was rapid below the pond indicating the importance of vertical preferential flow paths in the shallow unsaturated zone, especially to depths where agricultural disturbance occurs. Lateral flow of water at shallow depths was extensive and spatially non-uniform, reaching up to 10. m from the pond within 2. months. Within 1. month, the wetting front reached a textural boundary at 4-5. m between the fine-textured soil and sandy alluvium, now a potential capillary barrier which, prior to extensive irrigation withdrawals, was below the water table. Within 10. weeks, tracer was detectable at the water table which is presently about 12. m below land surface. Results indicate that 43% of percolation may be through preferential flow paths and that any water breaking through the capillary barrier (as potential recharge) likely does so in fingers which are difficult to detect with coring methods. In other areas where water levels have declined and soils have similar properties, the potential for transport of agricultural chemicals to the aquifer may be greater than previously assumed. ?? 2010 .

Evaluation of diffuse and preferential flow pathways of infiltrated precipitation and irrigation using oxygen and hydrogen isotopes

NASA Astrophysics Data System (ADS)

Ma, Bin; Liang, Xing; Liu, Shaohua; Jin, Menggui; Nimmo, John R.; Li, Jing

2017-05-01

Subsurface-water flow pathways in three different land-use areas (non-irrigated grassland, poplar forest, and irrigated arable land) in the central North China Plain were investigated using oxygen (18O) and hydrogen (2H) isotopes in samples of precipitation, soils, and groundwater. Soil water in the top 10 cm was significantly affected by both evaporation and infiltration. Water at 10-40 cm depth in the grassland and arable land, and 10-60 cm in poplar forest, showed a relatively short residence time, as a substantial proportion of antecedent soil water was mixed with a 92-mm storm infiltration event, whereas below those depths (down to 150 cm), depleted δ18O spikes suggested that some storm water bypassed the shallow soil layers. Significant differences, in soil-water content and δ18O values, within a small area, suggested that the proportion of immobile soil water and water flowing in subsurface pathways varies depending on local vegetation cover, soil characteristics and irrigation applications. Soil-water δ18O values revealed that preferential flow and diffuse flow coexist. Preferential flow was active within the root zone, independent of antecedent soil-water content, in both poplar forest and arable land, whereas diffuse flow was observed in grassland. The depleted δ18O spikes at 20-50 cm depth in the arable land suggested the infiltration of irrigation water during the dry season. Temporal isotopic variations in precipitation were subdued in the shallow groundwater, suggesting more complete mixing of different input waters in the unsaturated zone before reaching the shallow groundwater.

Rational Water and Nitrogen Management Improves Root Growth, Increases Yield and Maintains Water Use Efficiency of Cotton under Mulch Drip Irrigation

PubMed Central

Zhang, Hongzhi; Khan, Aziz; Tan, Daniel K. Y.; Luo, Honghai

2017-01-01

There is a need to optimize water-nitrogen (N) applications to increase seed cotton yield and water use efficiency (WUE) under a mulch drip irrigation system. This study evaluated the effects of four water regimes [moderate drip irrigation from the third-leaf to the boll-opening stage (W1), deficit drip irrigation from the third-leaf to the flowering stage and sufficient drip irrigation thereafter (W2), pre-sowing and moderate drip irrigation from the third-leaf to the boll-opening stage (W3), pre-sowing and deficit drip irrigation from the third-leaf to the flowering stage and sufficient drip irrigation thereafter (W4)] and N fertilizer at a rate of 520 kg ha-1 in two dressing ratios [7:3 (N1), 2:8 (N2)] on cotton root morpho-physiological attributes, yield, WUE and the relationship between root distribution and dry matter production. Previous investigations have shown a strong correlation between root activity and water consumption in the 40–120 cm soil layer. The W3 and especially W4 treatments significantly increased root length density (RLD), root volume density (RVD), root mass density (RMD), and root activity in the 40–120 cm soil layer. Cotton RLD, RVD, RMD was decreased by 13.1, 13.3, and 20.8%, respectively, in N2 compared with N1 at 70 days after planting (DAP) in the 0–40 cm soil layer. However, root activity in the 40–120 cm soil layer at 140 DAP was 31.6% higher in N2 than that in N1. Total RMD, RLD and root activity in the 40–120 cm soil were significantly and positively correlated with shoot dry weight. RLD and root activity in the 40–120 cm soil layer was highest in the W4N2 treatments. Therefore increased water consumption in the deep soil layers resulted in increased shoot dry weight, seed cotton yield and WUE. Our data can be used to develop a water-N management strategy for optimal cotton yield and high WUE. PMID:28611817

Water and salt dynamics and the hydraulic conductivity feedback: irreversible soil degradation and reclamation opportunities

NASA Astrophysics Data System (ADS)

Mau, Yair; Porporato, Amilcare

2017-04-01

We present a model for the dynamics of soil water, salt concentration and exchangeable sodium fraction in the root zone, driven by irrigation water of various qualities and stochastic rainfall. The main nonlinear feedback is the decrease in hydraulic conductivity for low salinity and/or high sodicity levels. The three variables have quite disparate characteristic time scales: soil water can vary two or three orders of magnitude faster than the exchangeable sodium fraction. In certain limiting cases in which the input of water is constant, the system can be simplified by eliminating the equation for soil water, allowing a full description of the dynamics in the two-dimensional salinity-sodicity phase space. We estimate soil structure degradation time scales for high sodium-adsorption-ratio irrigation water, and delineate the regions in the salinity-sodicity phase space where sodium-induced degradation is effectively irreversible. This apparent irreversibility is the result of relatively long evolution time scales with respect to human activity. When we take into account stochastic rainfall—and the accompanying wetting and drying cycles—the system produces a myriad of statistical steady states. This means that equal environmental conditions can produce different outcomes, accessible to each other only by large interventions, such as temporary changes in the quality of irrigation water or one-time amendment use. Our characterization of the dynamics of water and salt in the root zone, and how it depends on environmental parameters, offers us opportunities to control and reclaim degraded states making optimal resource use. We show an example of sodic soil reclamation through calcium-based fertigation, with minimal time (and applied water) expenditure.

Ultrasonic irrigation of a maxillary lateral incisor with perforation of the apical third of the root.

PubMed

Tsurumachi, Tamotsu; Takita, Toshiya; Hashimoto, Kazuhiro; Katoh, Takeshi; Ogiso, Bunnai

2010-12-01

We describe the successful use of a combination of nonsurgical root canal treatment and ultrasonic irrigation for collaborative management of a maxillary left lateral incisor with perforation of the apical third of the root. During the endodontic treatment procedure, the ultrasonically activated tip was used for intracanal irrigation. The area of perforation in the apical third of the root and the main root canal space were obturated with gutta-percha and root canal sealer, using a lateral condensation method. A follow-up clinical and radiographic examination at 5 years after treatment showed an asymptomatic tooth with excellent osseous healing.

The sensitivity of southeastern United States climate to varying irrigation vigor

NASA Astrophysics Data System (ADS)

Selman, Christopher; Misra, Vasubandhu

2016-07-01

Four regional climate model runs centered on the Southeast United States (SEUS) assuming a crop growing season of May through October are irrigated at 25% (IRR25), 50% (IRR50), 75% (IRR75), and 100% (IRR100) of the root zone porosity to assess the sensitivity of the SEUS climate to irrigation. A fifth run, assuming no irrigation (CTL), is used as the basis for comparison. Across all IRR runs, it is found that there is a general reduction in seasonal mean precipitation over the irrigated cells relative to CTL. This manifests as an increase in dry (0-1 mm/d) days and reduction in > 1 mm/d rainfall events. A comparative moisture budget reveals that area-averaged precipitation over the irrigated cells displays a reduction in precipitation and runoff in IRR100 with a weaker reduction in IRR25. This is despite an increase in vertically integrated moisture convergence and local evaporation. We find that irrigation increases the lower atmospheric stability, which in turn reduces the convective rainfall over the irrigated areas. Seasonally averaged temperatures reduce over irrigated areas, with the intensity of the reduction increasing with irrigation vigor. This is largely attributed to a repartitioning of sensible heat flux into latent heat flux. There is also, however, a small increase of heat flow to deeper soil layers. Precipitation ahead of transient cold fronts is also reduced by irrigation as they pass over irrigated cells, owing to the increased stability in the lower troposphere. The intensity of this precipitation reduction becomes more intense as irrigation vigor increases. Lastly, heat waves in the SEUS are reduced in intensity over irrigated cells.

Optodynamic Phenomena During Laser-Activated Irrigation Within Root Canals

NASA Astrophysics Data System (ADS)

Lukač, Nejc; Gregorčič, Peter; Jezeršek, Matija

2016-07-01

Laser-activated irrigation is a powerful endodontic treatment for smear layer, bacteria, and debris removal from the root canal. In this study, we use shadow photography and the laser-beam-transmission probe to examine the dynamics of laser-induced vapor bubbles inside a root canal model and compare ultrasonic needle irrigation to the laser method. Results confirm important phenomenological differences in the two endodontic methods with the laser method resulting in much deeper irrigation. Observations of simulated debris particles show liquid vorticity effects which in our opinion represents the major cleaning mechanism.

Irrigant flow within a prepared root canal using various flow rates: a Computational Fluid Dynamics study.

PubMed

Boutsioukis, C; Lambrianidis, T; Kastrinakis, E

2009-02-01

To study using computer simulation the effect of irrigant flow rate on the flow pattern within a prepared root canal, during final irrigation with a syringe and needle. Geometrical characteristics of a side-vented endodontic needle and clinically realistic flow rate values were obtained from previous and preliminary studies. A Computational Fluid Dynamics (CFD) model was created using FLUENT 6.2 software. Calculations were carried out for five selected flow rates (0.02-0.79 mL sec(-1)) and velocity and turbulence quantities along the domain were evaluated. Irrigant replacement was limited to 1-1.5 mm apical to the needle tip for all flow rates tested. Low-Reynolds number turbulent flow was detected near the needle outlet. Irrigant flow rate affected significantly the flow pattern within the root canal. Irrigation needles should be placed to within 1 mm from working length to ensure fluid exchange. Turbulent flow of irrigant leads to more efficient irrigant replacement. CFD represents a powerful tool for the study of irrigation.

Influence of different final irrigation regimens and various endodontic filling materials on vertical root fracture resistance.

PubMed

Sungur, D D; Altundasar, E; Uzunoglu, E; Yilmaz, Z

2016-01-01

The aim of this study was to evaluate the influence of different endodontic materials and final irrigation regimens on vertical root fracture (VRF) resistance. Eighty human teeth were prepared then assigned into two groups (n = 40) according to the final irrigations. G1: 5 mL, 5.25% sodium hypochlorite (NaOCl), G2: 5 mL, 2% chlorhexidine gluconate (CHX). Each group was assigned into four subgroups according to the obturation system used (n = 10): A: iRoot SP/single gutta-percha cone (SGP), B: Only iRoot SP, C: Mineral trioxide aggregate (MTA)-Fillapex/SGP, D: AH26/SGP. The specimens were embedded in acrylic molds and subjected to compressive loading at a rate of 1 mm min until VRF occurred. Data were analyzed via three-way ANOVA tests. The statistically significant difference was found among groups (P < 0.05). The G1A and G1B and G1D revealed significantly higher-VRF values than G1C (P = 0.023). The roots filled with MTA-Fillapex revealed lower-VRF values than the other subgroups (P < 0.05). Groups irrigated with NaOCl had significantly lower-VRF values than the groups irrigated with CHX (P < 0.05). Final irrigation regimens could alter VRF resistance of root canals filled with different obturation technique and root canal sealers.

Methylmercury production in and export from agricultural wetlands in California, USA: the need to account for physical transport processes into and out of the root zone

USGS Publications Warehouse

Bachand, Philip A.M.; Bachand, Sandra M.; Fleck, Jacob A.; Alpers, Charles N.; Stephenson, Mark; Windham-Myers, Lisamarie

2014-01-01

Concentration and mass balance analyses were used to quantify methylmercury (MeHg) loads from conventional (white) rice, wild rice, and fallowed fields in northern California's Yolo Bypass. These analyses were standardized against chloride to distinguish transport pathways and net ecosystem production (NEP). During summer, chloride loads were both exported with surface water and moved into the root zone at a 2:1 ratio. MeHg and dissolved organic carbon (DOC) behaved similarly with surface water and root zone exports at ~ 3:1 ratio. These trends reversed in winter with DOC, MeHg, and chloride moving from the root zone to surface waters at rates opposite and exceeding summertime root zone fluxes. These trends suggest that summer transpiration advectively moves constituents from surface water into the root zone, and winter diffusion, driven by concentration gradients, subsequently releases those constituents into surface waters. The results challenge a number of paradigms regarding MeHg. Specifically, biogeochemical conditions favoring microbial MeHg production do not necessarily translate to synchronous surface water exports; MeHg may be preserved in the soils allowing for release at a later time; and plants play a role in both biogeochemistry and transport. Our calculations show that NEP of MeHg occurred during both summer irrigation and winter flooding. Wild rice wet harvesting and winter flooding of white rice fields were specific practices that increased MeHg export, both presumably related to increased labile organic carbon and disturbance. Outflow management during these times could reduce MeHg exports. Standardizing MeHg outflow:inflow concentration ratios against natural tracers (e.g. chloride, EC) provides a simple tool to identify NEP periods. Summer MeHg exports averaged 0.2 to 1 μg m− 2 for the different agricultural wetland fields, depending upon flood duration. Average winter MeHg exports were estimated at 0.3 μg m− 2. These exports are within the range reported for other shallow aquatic systems.

Methylmercury production in and export from agricultural wetlands in California, USA: the need to account for physical transport processes into and out of the root zone.

PubMed

Bachand, P A M; Bachand, S M; Fleck, J A; Alpers, C N; Stephenson, M; Windham-Myers, L

2014-02-15

Concentration and mass balance analyses were used to quantify methylmercury (MeHg) loads from conventional (white) rice, wild rice, and fallowed fields in northern California's Yolo Bypass. These analyses were standardized against chloride to distinguish transport pathways and net ecosystem production (NEP). During summer, chloride loads were both exported with surface water and moved into the root zone at a 2:1 ratio. MeHg and dissolved organic carbon (DOC) behaved similarly with surface water and root zone exports at ~3:1 ratio. These trends reversed in winter with DOC, MeHg, and chloride moving from the root zone to surface waters at rates opposite and exceeding summertime root zone fluxes. These trends suggest that summer transpiration advectively moves constituents from surface water into the root zone, and winter diffusion, driven by concentration gradients, subsequently releases those constituents into surface waters. The results challenge a number of paradigms regarding MeHg. Specifically, biogeochemical conditions favoring microbial MeHg production do not necessarily translate to synchronous surface water exports; MeHg may be preserved in the soils allowing for release at a later time; and plants play a role in both biogeochemistry and transport. Our calculations show that NEP of MeHg occurred during both summer irrigation and winter flooding. Wild rice wet harvesting and winter flooding of white rice fields were specific practices that increased MeHg export, both presumably related to increased labile organic carbon and disturbance. Outflow management during these times could reduce MeHg exports. Standardizing MeHg outflow:inflow concentration ratios against natural tracers (e.g. chloride, EC) provides a simple tool to identify NEP periods. Summer MeHg exports averaged 0.2 to 1 μg m(-2) for the different agricultural wetland fields, depending upon flood duration. Average winter MeHg exports were estimated at 0.3 μg m(-2). These exports are within the range reported for other shallow aquatic systems. Copyright © 2013 Elsevier B.V. All rights reserved.

Comparative antibacterial efficacies of hydrodynamic and ultrasonic irrigation systems in vitro.

PubMed

Cachovan, Georg; Schiffner, Ulrich; Altenhof, Saskia; Guentsch, Arndt; Pfister, Wolfgang; Eick, Sigrun

2013-09-01

To ensure root canal treatment success, endodontic microbiota should be efficiently reduced. The in vitro bactericidal effects of a hydrodynamic system and a passive ultrasonic irrigation system were compared. Single-rooted extracted teeth (n = 250) were contaminated with suspensions of Enterococcus faecalis ATCC 29212, mixed aerobic cultures, or mixed anaerobic cultures. First, the antibacterial effects of the hydrodynamic system (RinsEndo), a passive ultrasonic irrigation system (Piezo smart), and manual rinsing with 0.9% NaCl (the control) were compared. Colony-forming units were counted. Second, the 2 systems were used with 1.5% sodium hypochlorite (NaOCl) alone or NaOCl + 0.2% chlorhexidine (CHX). The colony-forming units in the treated and untreated roots were determined during a period of 5 days. Both irrigation systems reduced bacterial numbers more effectively than manual rinsing (P < .001). With NaCl, ultrasonic activated irrigation reduced bacterial counts significantly better than hydrodynamic irrigation (P = .042). The NaOCl + CHX combination was more effective than NaOCl alone for both systems (P < .001), but hydrodynamic irrigation was more effective with NaOCl + CHX than the passive ultrasonic irrigation system. Both irrigation systems, when combined with NaOCl + CHX, removed bacteria from root canals. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Comparison of the EndoVac system and conventional needle irrigation on removal of the smear layer in primary molar root canals.

PubMed

Buldur, B; Kapdan, A

2017-09-01

This study aimed to compare the EndoVac system and conventional needle irrigation in removing smear layer (SR) from primary molar root canals. Fifty extracted human primary second molar roots were instrumented up to an apical size of 0.04/35 and randomly divided into two main groups; Group 1: EndoVac system (n = 25) and Group 2: Conventional needle irrigation (n = 25) and three subgroups (a) NaOCl + ethylenediaminetetraacetic acid (EDTA) (n = 20) (b) ozonated water (OW) + EDTA (n = 20) and (c) saline (control, n = 10). After a standardized final irrigation protocol performed for all teeth, scanning electron microscope images were taken at ×1000 magnification for each thirds of each root canal. Data were analyzed by the weighted kappa, Kruskal-Wallis, and Wilcoxon signed rank tests. EndoVac was more effective than conventional needle in the removal of SR from the apical third of the root canal system (P < 0.05). The OW + EDTA regimen provided similar SR removal compared with NaOCl + EDTA. EndoVac has better performance than conventional needle irrigation in the removal of the SR in the apical thirds of the primary molar root canals. As a final irrigation regimen, the OW + EDTA regimen is as effective as the NaOCl + EDTA regimen.

The comparison of the effect of endodontic irrigation on cell adherence to root canal dentin.

PubMed

Ring, Karla C; Murray, Peter E; Namerow, Kenneth N; Kuttler, Sergio; Garcia-Godoy, Franklin

2008-12-01

The purpose of this study was to compare the effect of 10 different endodontic irrigation and chelating treatments on dental pulp stem cell (DPSC) attachment to root canal surfaces. Thirty-eight extracted human nondiseased single-canal teeth were cleaned and shaped using ProTaper and ProFile rotary instrumentation (Tulsa Dentsply, Tulsa, OK). The irrigation treatments investigated were 6% sodium hypochlorite, 2% chlorhexidine gluconate, Aquatine Endodontic Cleanser, and Morinda citrifolia juice. The irrigation treatments were used in conjunction with EDTA or MTAD. The instrumented teeth were immediately placed in cell culture with confluent DPSCs for 1 week. The number of attached DPSCs appeared to be correlated with the cytotoxicity of the root canal irrigating solution (analysis of variance, p < 0.0001). The presence or absence of the smear layer had little influence on DPSC activity (chi-square, p > 0.05). The results suggest that biocompatible irrigants are needed to promote DPSC attachment to root canal dentin, which is essential to accomplish some regenerative endodontic therapies.

Treated wastewater and Nitrate transport beneath irrigated fields near Dodge city, Kansas

USGS Publications Warehouse

Sophocleous, M.; Townsend, M.A.; Vocasek, F.; Ma, Liwang; Ashok, K.C.

2010-01-01

Use of secondary-treated municipal wastewater for crop irrigation south of Dodge City, Kansas, where the soils are mainly of silty clay loam texture, has raised a concern that it has resulted in high nitratenitrogen concentrations (10-50 mg/kg) in the soil and deeper vadose zone, and also in the underlying deep (20-45 m) ground water. The goal of this field-monitoring project was to assess how and under what circumstances nitrogen (N) nutrients under cultivated corn that is irrigated with this treated wastewater can reach the deep ground water of the underlying High Plains aquifer, and what can realistically be done to minimize this problem. We collected 15.2-m-deep cores for physical and chemical properties characterization; installed neutron moisture-probe access tubes and suction lysimeters for periodic measurements; sampled area monitoring, irrigation, and domestic wells; performed dye-tracer experiments to examine soil preferential-flow processes through macropores; and obtained climatic, crop, irrigation, and N-application rate records. These data and additional information were used in the comprehensive Root Zone Water Quality Model (RZWQM2) to identify key parameters and processes that influence N losses in the study area. We demonstrated that nitrate-N transport processes result in significant accumulations of N in the thick vadose zone. We also showed that nitrate-N in the underlying ground water is increasing with time and that the source of the nitrate is from the wastewater applications. RZWQM2 simulations indicated that macropore flow is generated particularly during heavy rainfall events, but during our 2005-06 simulations the total macropore flow was only about 3% of precipitation for one of two investigated sites, whereas it was more than 13% for the other site. Our calibrated model for the two wastewater-irrigated study sites indicated that reducing current levels of corn N fertilization by half or more to the level of 170 kg/ha substantially increases N-use efficiency and achieves near-maximum crop yield. Combining such measures with a crop rotation that includes alfalfa should further reduce the amounts of residual N in the soil, as indicated in one of the study sites that had alfalfa in past crop rotations.

Application of a single root-scale model to improve macroscopic modeling of root water uptake: focus on osmotic stress

NASA Astrophysics Data System (ADS)

Jorda, Helena; Perelman, Adi; Lazarovitch, Naftali; Vanderborght, Jan

2017-04-01

Root water uptake is a fundamental process in the hydrological cycle and it largely regulates the water balance in the soil vadose zone. Macroscopic stress functions are currently used to estimate the effect of salinity on root water uptake. These functions commonly assume stress to be a function of bulk salinity and of the plant sensitivity to osmotic stress expressed as the salinity at which transpiration is reduced by half or so called tolerance value. However, they fail to integrate additional relevant factors such as atmospheric conditions or root architectural traits. We conducted a comprehensive simulation study on a single root using a 3-D physically-based model that resolves flow and transport to individual root segments and that couples flow in the soil and root system. The effect of salt concentrations on root water uptake was accounted for by including osmotic water potential gradients between the solution at the soil root interface and the root xylem sap in the hydraulic gradient between the soil and root. A large set of factors were studied, namely, potential transpiration rate and dynamics, root length density (RLD), irrigation water quality and irrigation frequency, and leaching fraction. Results were fitted to the macroscopic function developed by van Genuchten and Hoffman (1984) and the dependency of osmotic stress and the fitted macroscopic parameters on the studied factors was evaluated. Osmotic stress was found to be highly dependent on RLD. Low RLDs result in a larger stress to the plant due to high evaporative demand per root length unit. In addition, osmotic stress was positively correlated to potential transpiration rate, and sinusoidal potential transpiration lead to larger stress than when imposed as a constant boundary condition. Macroscopic parameters are usually computed as single values for each crop and used for the entire growing season. However, our study shows that both tolerance value and shape parameter p from the van Genuchten and Hoffman (1984) function were highly dependent on both potential transpiration and RLD. Plant salt tolerance was lower under high evaporative demand and lower RLD. In addition, the shape of the stress curve, which is defined by p, was found to be steeper under larger RLD and low transpiration rate. Time-variant macroscopic parameters based on knowledge of current potential transpiration rate per root unit length would be more convenient to accurately predict osmotic stress, and hence root water uptake, during a growing season. In a next step, simulations considering the whole root systems will be conducted to assess how macroscopic parameters are also related to root architectural characteristics. van Genuchten, M.T., Hoffman, G., 1984. Analysis of crop production. Soil Salin. Irrig. Springer Berl. 258-271.

Simulations and field observations of root water uptake in plots with different soil water availability.

NASA Astrophysics Data System (ADS)

Cai, Gaochao; Vanderborght, Jan; Couvreur, Valentin; Javaux, Mathieu; Vereecken, Harry

2015-04-01

Root water uptake is a main process in the hydrological cycle and vital for water management in agronomy. In most models of root water uptake, the spatial and temporal soil water status and plant root distributions are required for water flow simulations. However, dynamic root growth and root distributions are not easy and time consuming to measure by normal approaches. Furthermore, root water uptake cannot be measured directly in the field. Therefore, it is necessary to incorporate monitoring data of soil water content and potential and root distributions within a modeling framework to explore the interaction between soil water availability and root water uptake. But, most models are lacking a physically based concept to describe water uptake from soil profiles with vertical variations in soil water availability. In this contribution, we present an experimental setup in which root development, soil water content and soil water potential are monitored non-invasively in two field plots with different soil texture and for three treatments with different soil water availability: natural rain, sheltered and irrigated treatment. Root development is monitored using 7-m long horizontally installed minirhizotubes at six depths with three replicates per treatment. The monitoring data are interpreted using a model that is a one-dimensional upscaled version of root water uptake model that describes flow in the coupled soil-root architecture considering water potential gradients in the system and hydraulic conductances of the soil and root system (Couvreur et al., 2012). This model approach links the total root water uptake to an effective soil water potential in the root zone. The local root water uptake is a function of the difference between the local soil water potential and effective root zone water potential so that compensatory uptake in heterogeneous soil water potential profiles is simulated. The root system conductance is derived from inverse modelling using measurements of soil water potentials, water contents, and root distributions. The results showed that this modelling approach reproduced soil water dynamics well in the different plots and treatments. Root water uptake reduced when the effective soil water potential decreased to around -70 to -100 kPa in the root zone. Couvreur, V., Vanderborght, J., and Javaux, M.: A simple three dimensional macroscopic root water uptake model based on the hydraulic architecture approach, Hydrol. Earth Syst. Sci., 16, 2957-2971, doi:10.5194/hess-16-2957-2012, 2012.

Simultaneous effects of leaf irradiance and soil moisture on growth and root system architecture of novel wheat genotypes: implications for phenotyping.

PubMed

Nagel, Kerstin A; Bonnett, David; Furbank, Robert; Walter, Achim; Schurr, Ulrich; Watt, Michelle

2015-09-01

Plants in the field are exposed to varying light and moisture. Agronomic improvement requires knowledge of whole-plant phenotypes expressed in response to simultaneous variation in these essential resources. Most phenotypes, however, have been described from experiments where resources are varied singularly. To test the importance of varying shoot and root resources for phenotyping studies, sister pre-breeding lines of wheat were phenotyped in response to independent or simultaneous exposure to two light levels and soil moisture profiles. The distribution and architecture of the root systems depended strongly on the moisture of the deeper soil layer. For one genotype, roots, specifically lateral roots, were stimulated to grow into moist soil when the upper zone was well-watered and were inhibited by drier deep zones. In contrast, the other genotype showed much less plasticity and responsiveness to upper moist soil, but maintained deeper penetration of roots into the dry layer. The sum of shoot and root responses was greater when treated simultaneously to low light and low soil water, compared to each treatment alone, suggesting the value of whole plant phenotyping in response to multiple conditions for agronomic improvement. The results suggest that canopy management for increased irradiation of leaves would encourage root growth into deeper drier soil, and that genetic variation within closely related breeding lines may exist to favour surface root growth in response to irrigation or in-season rainfall. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Impacts of deficit irrigation and altered rooting patterns on soil structure and associated soil properties

USDA-ARS?s Scientific Manuscript database

A better understanding of belowground systems and overall management impacts on soil health is needed to improve crop production and long-term sustainability under deficit irrigation. This study investigates effects of deficit irrigation on rooting patterns in maize and subsequent impacts on soil pr...

A new method to enhance rhizosheath formation

NASA Astrophysics Data System (ADS)

Ahmadi, katayoun; Zarebanadkouki, Mohsen; Kuzyakov, Yakov; Carminati, Andrea

2016-04-01

The rhizosheath is defined as the soil that adheres to the roots by help of root hairs and mucilage. Rhizosheath maintain the contact between roots and soil improving water and nutrient uptake. Here we introduce: (1) a technique to quantify the formation of rhizosheath around the roots, and (2) a method to enhance the formation of rhizosheath around the roots. Additionally, we measured the relation between rhizosheath thickness and the carbon content and enzyme activities in the rhizosphere. We grew lupine plants in aluminum containers (28×30×1 cm) filled with a sandy soil. When plants were two weeks-old and the soil had a water content of 30%, we stopped the irrigation and let the plants to uptake water to a soil water content of 4-5%. Thereafter, half of the plants (4 plants) were irrigated with water and the other half with water with an additive (international patent is pending). We repeated the drying and rewetting cycle three times. At the end of the third drying cycle, when plants were 40 days old and soil had a water content of 4-5%,the containers were opened and roots and their surrounding soils were gently collected. We used imaging to quantify the rhizosheath formation. The method consists of scanning the roots and the surrounding soil using the Winrhizo software. By image analysis we quantified the thickness of roots and their rhizosheath. The plants irrigated with the additive had 63% thicker rhizopsheath than plants irrigated with water. So, the additive enhanced gelation of mucilage exuded by the roots. Carbon content and enzyme activity in the collected rhizosheath showed that the rhizosheath of plants irrigated with the additive had higher carbon content and enzyme activity than the rhizopsheath of plants irrigated with water. The new method to increase rhizosheath has the great advantage that can be easily applied to the irrigation water to improve plant uptake of water and nutrients in semiarid and arid areas.

The impact of an extreme case of irrigation on the southeastern United States climate

NASA Astrophysics Data System (ADS)

Selman, Christopher; Misra, Vasubandhu

2017-02-01

The impacts of irrigation on southeast United States diurnal climate are investigated using simulations from a regional climate model. An extreme case is assumed, wherein irrigation is set to 100 % of field capacity over the growing season of May through October. Irrigation is applied to the root zone layers of 10-40 and 40-100 cm soil layers only. It is found that in this regime there is a pronounced decrease in monthly averaged temperatures in irrigated regions across all months. In non-irrigated areas a slight warming is simulated. Diurnal maximum temperatures in irrigated areas warm, while diurnal minimum temperatures cool. The daytime warming is attributed to an increase in shortwave flux at the surface owing to diminished low cloud cover. Nighttime and daily mean cooling result as a consequence repartitioning of energy into latent heat flux over sensible heat flux, and of a higher net downward ground heat flux. Excess heat is transported into the deep soil layer, preventing a rapidly intensifying positive feedback loop. Both diurnal and monthly average precipitations are reduced over irrigated areas at a magnitude and spatial pattern similar to one another. Due to the excess moisture availability, evaporation is seen to increase, but this is nearly balanced by a corresponding reduction in sensible heat flux. Concomitant with additional moisture availability is an increase in both transient and stationary moisture flux convergences. However, despite the increase, there is a large-scale stabilization of the atmosphere stemming from a cooled surface.

Reduction of hard-tissue debris accumulation during rotary root canal instrumentation by etidronic acid in a sodium hypochlorite irrigant.

PubMed

Paqué, Frank; Rechenberg, Dan-Krister; Zehnder, Matthias

2012-05-01

Hard-tissue debris is accumulated during rotary instrumentation. This study investigated to what extent a calcium-complexing agent that has good short-term compatibility with sodium hypochlorite (NaOCl) could reduce debris accumulation when applied in an all-in-one irrigant during root canal instrumentation. Sixty extracted mandibular molars with isthmuses in the mesial root canal system were selected based on prescans using a micro-computed tomography system. Thirty teeth each were randomly assigned to be instrumented with a rotary system and irrigated with either 2.5% NaOCl or 2.5% NaOCl containing 9% (wt/vol) etidronic acid (HEBP). Using a side-vented irrigating tip, 2 mL of irrigant was applied by 1 blinded investigator to the mesial canals after each instrument. Five milliliters of irrigant was applied per canal as the final rinse. Mesial root canal systems were scanned at high resolution before and after treatment, and accumulated hard-tissue debris was calculated as vol% of the original canal anatomy. Values between groups were compared using the Student's t test (α < .05). Irrigation with 2.5% NaOCl resulted in 5.5 ± 3.6 vol% accumulated hard-tissue debris compared with 3.8 ± 1.8 vol% when HEBP was contained in the irrigant (P < .05). A hypochlorite-compatible chelator can reduce but not completely prevent hard-tissue debris accumulation during rotary root canal instrumentation. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Role of the confinement of a root canal on jet impingement during endodontic irrigation

NASA Astrophysics Data System (ADS)

Verhaagen, B.; Boutsioukis, C.; Heijnen, G. L.; van der Sluis, L. W. M.; Versluis, M.

2012-12-01

During a root canal treatment the root canal is irrigated with an antimicrobial fluid, commonly performed with a needle and a syringe. Irrigation of a root canal with two different types of needles can be modeled as an impinging axisymmetric or non-axisymmetric jet. These jets are investigated experimentally with high-speed Particle Imaging Velocimetry, inside and outside the confinement (concave surface) of a root canal, and compared to theoretical predictions for these jets. The efficacy of irrigation fluid refreshment with respect to the typical reaction time of the antimicrobial fluid with a biofilm is characterized with a non-dimensional Damköhler number. The pressure that these jets induce on a wall or at the apex of the root canal is also measured. The axisymmetric jet is found to be stable and its velocity agrees with the theoretical prediction for this type of jet, however, a confinement causes instabilities to the jet. The confinement of the root canal has a pronounced influence on the flow, for both the axisymmetric and non-axisymmetric jet, by reducing the velocities by one order of magnitude and increasing the pressure at the apex. The non-axisymmetric jet inside the confinement shows a cascade of eddies with decreasing velocities, which at the apex does not provide adequate irrigation fluid refreshment.

Evaluation of smear layer removal and marginal adaptation of root canal sealer after final irrigation using ethylenediaminetetraacetic, peracetic, and etidronic acids with different concentrations.

PubMed

Ulusoy, Özgür İlke; Zeyrek, Salev; Çelik, Bülent

2017-07-01

The purpose of this study was to investigate the effects of different irrigation solutions on the smear layer removal and marginal adaptation of a resin-based sealer to root canal dentine. A total of 152 instrumented roots were irrigated with the following irrigants: 9,18% etidronic acid (HEBP), 0.5, 1,2% peracetic acid (PAA), 17% ethylenediaminetetraacetic acid (EDTA), saline. The amount of smear layer was evaluated using scanning electron microscope (SEM) in seventy root samples. Eighty-two roots were filled with AH Plus and gutta-percha. Slices obtained from apical third of each specimen were viewed with SEM to assess marginal adaptation. Use of 9% and 18% HEBP resulted in more efficient smear layer removal in the apical third than the other chelators (p < 0.05). Higher smear layer scores in the coronal and middle thirds were obtained from 0.5%, 1% PAA groups. Regarding marginal adaptation, 18% HEBP group showed the lowest gap size values (p < 0.05), and better marginal adaptation. Etidronic acid is a promising candidate for final irrigation of root canals. © 2017 Wiley Periodicals, Inc.

Heavy metal accumulation by Corchorus olitorius L. irrigated with wastewater.

PubMed

Ahmed, Dalia A; Slima, Dalia F

2018-05-01

Many agricultural soils in Egypt irrigated with untreated wastewater. Herein, we investigated the effect of untreated industrial wastewater irrigation on the soil and fodder plant Corchorus olittorius (Jew mallow). It also aimed to assess its effect on the growth measurements as well as analyses of soils, irrigation waters, and plants for heavy metal and nutrient concentrations. Significant differences between irrigation waters and soil irrigated with fresh and wastewater were recognized. Wastewater irrigation leads to remarkable reduction in the growth parameters and reduced its vegetative biomass. The concentration of Pb, Cd, Cr, Cu, Fe, and Zn were high significant and above phytotoxic concentrations in leaves (edible part) and roots of wastewater-irrigated plant. The present study indicated that Jew mallow plant tends to phytostabilize (Cd, Ni, and Mn) in its root and had the ability to translocate (Pb, Cu, Cr, Fe, and Zn) to its leaves. Higher concentrations of Cd, Cu, Cr, Pb, Fe, Mn, Ni, and Zn in the roots than leaves indicate that the roots are hyper-accumulators for Pb, Cr, Cu, Fe, and Zn more than the leaves. The research study recommended that there is a need to protect the soil from contamination through regular monitoring and not to cultivate Jew mallow in wastewater-irrigated soil and that it had a high capacity to accumulate heavy metals in its edible part and causes several harmful health effects for consumers.

Evaluation of diffuse and preferential flow pathways of infiltratedprecipitation and irrigation using oxygen and hydrogen isotopes

USGS Publications Warehouse

Ma, Bin; Liang, Xing; Liu, Shaohua; Jin, Menggui; Nimmo, John R.; Li, Jingxin

2017-01-01

Subsurface-water flow pathways in three different land-use areas (non-irrigated grassland, poplar forest, and irrigated arable land) in the central North China Plain were investigated using oxygen (18O) and hydrogen (2H) isotopes in samples of precipitation, soils, and groundwater. Soil water in the top 10 cm was significantly affected by both evaporation and infiltration. Water at 10–40 cm depth in the grassland and arable land, and 10–60 cm in poplar forest, showed a relatively short residence time, as a substantial proportion of antecedent soil water was mixed with a 92-mm storm infiltration event, whereas below those depths (down to 150 cm), depleted δ18O spikes suggested that some storm water bypassed the shallow soil layers. Significant differences, in soil-water content and δ18O values, within a small area, suggested that the proportion of immobile soil water and water flowing in subsurface pathways varies depending on local vegetation cover, soil characteristics and irrigation applications. Soil-water δ18O values revealed that preferential flow and diffuse flow coexist. Preferential flow was active within the root zone, independent of antecedent soil-water content, in both poplar forest and arable land, whereas diffuse flow was observed in grassland. The depleted δ18O spikes at 20–50 cm depth in the arable land suggested the infiltration of irrigation water during the dry season. Temporal isotopic variations in precipitation were subdued in the shallow groundwater, suggesting more complete mixing of different input waters in the unsaturated zone before reaching the shallow groundwater.

Root Canal Irrigation: Chemical Agents and Plant Extracts Against Enterococcus faecalis

PubMed Central

Borzini, Letizia; Condò, Roberta; De Dominicis, Paolo; Casaglia, Adriano; Cerroni, Loredana

2016-01-01

Background: There are various microorganisms related to intra and extra-radicular infections and many of these are involved in persistent infections. Bacterial elimination from the root canal is achieved by means of the mechanical action of instruments and irrigation as well as the antibacterial effects of the irrigating solutions. Enterococcus faecalis can frequently be isolated from root canals in cases of failed root canal treatments. Antimicrobial agents have often been developed and optimized for their activity against endodontic bacteria. An ideal root canal irrigant should be biocompatible, because of its close contact with the periodontal tissues during endodontic treatment. Sodium hypoclorite (NaOCl) is one of the most widely recommended and used endodontic irrigants but it is highly toxic to periapical tissues. Objectives: To analyze the literature on the chemotherapeutic agent and plant extracts studied as root canal irrigants. In particularly, the study is focused on their effect on Enterococcus faecalis. Method: Literature search was performed electronically in PubMed (PubMed Central, MEDLINE) for articles published in English from 1982 to April 2015. The searched keywords were “endodontic irrigants” and “Enterococcus faecalis” and “essential oil” and “plant extracts”. Results: Many of the studied chemotherapeutic agents and plant extracts have shown promising results in vitro. Conclusion: Some of the considered phytotherapic substances, could be a potential alternative to NaOCl for the biomechanical treatment of the endodontic space. PMID:28217184

Comparison of Different Irrigants in the Removal of Endotoxins and Cultivable Microorganisms from Infected Root Canals

PubMed Central

Valera, Marcia Carneiro; Cardoso, Flávia Goulart da Rosa; Chung, Adriana; Xavier, Ana Cláudia Carvalho; Figueiredo, Mariana Diehl; Martinho, Frederico Canato; Palo, Renato Miotto

2015-01-01

This study was conducted to compare the effectiveness of different irrigants used to remove endotoxins and cultivable microorganisms during endodontic therapy. Forty root canals were contaminated and divided into groups according to the irrigant: 2% NaOCl + surfactant, 2% CHX, 2.5% NaOCl, and pyrogen-free saline solution (control). Samples were collected after root canal contamination (S1), after instrumentation (S2), and 7 days after instrumentation (S3). Microorganisms and endotoxins were recovered from 100% of the contaminated root canals (S1). At S2, 2% NaOCl + surfactant, 2% CHX, and 2.5% NaOCl were able to completely eliminate cultivable microorganisms. At S3, both 2% CHX and 2.5% NaOCl were effective in preventing C. albicans and E. coli regrowth, but E. faecalis was still detected. No microorganism species was recovered from root canals instrumented with 2% NaOCl + surfactant. At S2, a higher percentage value of endotoxin reduction was found for 2% NaOCl + surfactant (99.3%) compared to 2% CHX (98.9%) and 2.5% NaOCl (97.18%) (p < 0.05). Moreover, at S3, 2% NaOCl + surfactant (100%) was the most effective irrigant against endotoxins. All irrigants tested were effective in reducing microorganisms and endotoxins from root canals. Moreover, 2% NaOCl + surfactant was the most effective irrigant against endotoxins and regrowth of microorganisms. PMID:26346574

An in vitro evaluation of various irrigation techniques for the removal of double antibiotic paste from root canal surfaces

PubMed Central

GOKTURK, Hakan; OZKOCAK, Ismail; BUYUKGEBİZ, Fevzi; DEMİR, Osman

2016-01-01

ABSTRACT Objective The aim of this study was to investigate the effectiveness of conventional syringe irrigations, passive ultrasonic irrigation (PUI), Vibringe, CanalBrush, XP-endo Finisher, and laser-activated irrigation (LAI) systems in removing double antibiotic paste (DAP) from root canals. Material and Methods One hundred five extracted single-rooted teeth were instrumented. The roots were split longitudinally. Three standard grooves were created and covered with DAP. The roots were distributed into seven groups: Group 1, beveled needle irrigation; Group 2, double side-vented needle irrigation; Group 3, CanalBrush; Group 4, XP-endo Finisher; Group 5, Vibringe; Group 6, PUI; Group 7, LAI. The amount of remaining DAP was scored under a stereomicroscope. Results Group 4, Group 6, and Group 7 removed significantly more DAP than the other protocols in the coronal region. Group 7 was more efficient in the middle region; however, no significant difference was found between Group 7 and Group 6. No differences were found between groups in the apical region either, except for the comparisons between groups 7 and 2, and groups 2 and 3. Conclusions None of the investigated protocols were able to completely remove the DAP from the grooves. The Vibringe and XP-endo Finisher systems showed results similar to those of conventional needle irrigation. PMID:28076461

Effect of endodontic irrigating solutions on the microhardness and roughness of root canal dentin: an in vitro study.

PubMed

Patil, Chetan R; Uppin, Veerendra

2011-01-01

To evaluate the effect of widely used endodontic irrigating solutions on root dentin microhardness and surface roughness. One hundred twenty, non-carious extracted human permanent incisor teeth were selected. The crowns of the teeth were sectioned and the roots were separated longitudinally to get 240 specimens. These specimens were then divided into six groups according to the irrigating solutions used. The solutions used were 5% and 2.5% NaOCl solutions, 3% H2 O2 , 17% EDTA solution, 0.2% chlorhexidine gluconate, and distilled water. Then, the specimens were subjected to microhardness and roughness testing. The data were analyzed using ANOVA and Tukey's multiple comparison tests. The results of this study indicated that all irrigation solutions, except 0.2% chlorhexidine gluconate, decreased the microhardness of root dentin, and 3% H2 O2 and 0.2% chlorhexidine gluconate had no effect on surface roughness. Within the limitation of this study, it is concluded that 0.2% chlorhexidine gluconate seems to be an appropriate irrigation solution, because of its harmless effect on the microhardness and surface roughness of root canal dentin.

Effects of drought and irrigation on ecosystem functioning in a mature Scots pine forest

NASA Astrophysics Data System (ADS)

Dobbertin, Matthias; Brunner, Ivano; Egli, Simon; Eilmann, Britta; Graf Pannatier, Eisabeth; Schleppi, Patrick; Zingg, Andreas; Rigling, Andreas

2010-05-01

Climate change is expected to increase temperature and reduce summer precipitation in Switzerland. To study the expected effects of increased drought in mature forests two different approaches are in general possible: water can be partially or completely removed from the ecosystems via above- or below-canopy roofs or water can be added to already drought-prone ecosystems. Both methods have advantages and disadvantages. In our study water was added to a mature 90-year old Scots pine (Pinus sylvestris L.) forest with a few singe pubescent oaks (Quercus pubescens Willd.), located in the valley bottom of the driest region of Switzerland (Valais). In Valais, Scots pines are declining, usually with increased mortality rates following drought years. It was therefore of special interest to study here how water addition is changing forest ecosystem functioning. The irrigation experiment started in the summer of 2003. Out of eight 0.1 ha experimental plots, four were randomly selected for irrigation, the other four left as a control. Irrigation occurred during rainless nights between April and October, doubling the annual rainfall amount from 650 to 1300 mm. Irrigation water, taken from a near-by irrigation channel, added some nutrients to the plots, but nutrients which were deficient on the site, e.g. nitrogen and phosphorus, were not altered. Tree diameter, tree height and crown width were assessed before the start of the irrigation in winter 2002/2003 and after 7 years of the experiment in 2009/2010. Tree crown transparency (lack of foliage) and leaf area index (LAI) were annually assessed. Additionally, tree mortality was annually evaluated. Mycorrhizal fruit bodies were identified and counted at weekly intervals from 2003 until 2007. Root samples were taken in 2004 and 2005. In 2004 and 2005 wood formation of thirteen trees was analysed in weekly or biweekly intervals using the pinning method. These trees were felled in 2006 for stem, shoot and needle growth analysis. Soil water content was significantly reduced during irrigation periods. Irrigation doubled tree stem growth, increased shoot growth and thus increased volume growth and crown dimensions. Annual tree mortality rates were reduced by 50% in irrigated plots. The growing period for stem growth was extended in pines as a result of irrigation. Altogether, increased growth and reduced mortality significantly increased tree stem basal area at breast height per ha. As irrigation also increased needle length, estimated mean foliage amount per tree and stand leaf area index significantly increased. However, the number of needle generations was not altered or even reduced due to irrigation. Root growth, was less affected by irrigation and only resulted in increased fine root length. Species richness and fruit body numbers of mycorrhizal fungi were several times higher on the irrigated plots. Overall, it can be concluded that water availability was the main ecosystem limiting factor and that any changes in water availability will result in changes in ecosystem functioning. References Brunner I, Graf-Pannatier E, Frey B, Rigling A, Landolt W, Dobbertin M (2009) Morphological and physiological responses of Scots pine fine roots to water supply in a climatic dry area in Switzerland. Tree Physiology 29:541-550. Dobbertin M, Eilmann B, Bleuler P, Giuggiola A, Graf Pannatier E, Landolt W, Schleppi P, Rigling A (2010) Effect of irrigation on needle, shoot and stem growth in natural drought-exposed Pinus sylvestris forests, Tree Physiology, doi:10.1093/treephys/tpp123. Eilmann B, Zweifel R, Buchmann N, Fonti P, Rigling A (2009) Drought induced adaptation of the xylem in Pinus sylvestris and Quercus pubescens. Tree Physiology 29:1011-1020.

Leaf, woody, and root biomass of Populus irrigated with landfill leachate

Treesearch

Jill A. Zalesny; Ronald S., Jr. Zalesny; D.R. Coyle; R.B. Hall

2007-01-01

Poplar (Populus spp.) trees can be utilized for ecological leachate disposal when applied as an irrigation source for managed tree systems. Our objective was to evaluate differences in tree height, diameter, volume, and biomass of leaf, stem, branch, and root tissues of Populus trees after two seasons of irrigation with municipal...

Induced heterogeneity of soil water content and chemical properties by treated wastewater irrigation and its reclamation by freshwater irrigation

NASA Astrophysics Data System (ADS)

Rahav, Matan; Brindt, Naaran; Yermiyahu, Uri; Wallach, Rony

2017-06-01

The recognition of treated wastewater (TWW) as an alternative water resource is expanding in areas with a shortage of freshwater (FW) resources. Today, most orchards in Israel are irrigated with TWW. While the benefits of using TWW for irrigation are apparent, evidence of its negative effects on soil, trees, and yield is accumulating. This study, performed in a commercial TWW-irrigated citrus orchard in central Israel, examined the effects of (1) soil-wettability decrease due to prolonged TWW irrigation on the spatial and temporal distribution of water content and associated chemical properties in the root zone; (2) the conversion of irrigation in half of the TWW-irrigated research plot to FW (2012) for soil reclamation. Electrical resistivity tomography surveys in the substantially water repellent soils revealed that water flow is occurring along preferential flow paths in both plots, leaving behind a considerably nonuniform water-content distribution. This was despite the gradual relief in soil water repellency measured in the FW plots. Four soil-sampling campaigns (spring and fall, 2014-2016), performed in 0-20 and 20-40 cm layers of the research plot, revealed bimodal gravimetrically measured water-content distribution. The preferential flow led to uneven chemical-property distribution, with substantially high concentrations in the dry spots, and lower concentrations in the wet spots along the preferential flow paths. The average salt and nutrient concentrations, which were initially high in both plots, gradually dispersed with time, as concentrations in the FW plots decreased. Nevertheless, the efficiency of reclaiming TWW soil by FW irrigation appears low.

Nitrous oxide fluxes from cultivated areas and rangeland: U.S. High Plains

USGS Publications Warehouse

Weeks, Edwin P.; McMahon, Peter B.

2007-01-01

Concentration profiles of N2O, a greenhouse gas, and the conservative trace gases SF6 and the chlorofluorocarbons CFC-11, CFC-12, CFC-113, and were measured periodically through thick vadose zones at nine sites in the U.S. High Plains. The CFC and SF6 measurements were used to calibrate a one-dimensional gas diffusion model, using the parameter identification program UCODE. The calibrated model was used with N2O measurements to estimate average annual N2O flux from both the root zone and the deep vadose zone to the atmosphere. Estimates of root-zone N 2O fluxes from three rangeland sites ranged from near 0 to about 0.2 kg N2O-N ha-1 yr-1, values near the low end of the ranges determined for native grass from other studies. Estimates of root-zone N2O fluxes from two fields planted to corn (Zea mays L.) of about 2 to 6 kg N2O-N ha-1 yr-1 are similar to those determined for corn in other studies. Estimates of N2O flux from Conservation Reserve grassland converted from irrigated corn indicate that production of N2O is substantially reduced following conversion from cropland. Small N2O fluxes from the water table or from deep in the vadose zone occurred at three sites, ranging from 0.004 to 0.02 kg N 2O-N ha-1 yr-1. Our estimates of N2O flux represent space- and time-averaged values that should be useful to more fully evaluate the significance of instantaneous point flux measurements. ?? Soil Science Society of America.

How will climate change affect vine behaviour in different soils?

NASA Astrophysics Data System (ADS)

Leibar, Urtzi; Aizpurua, Ana; Morales, Fermin; Pascual, Inmaculada; Unamunzaga, Olatz

2014-05-01

Various agricultural sectors are sensitive to projected climate change. In this sense, the strong link between climate and grapevine phenology and berry quality suggests a relevant impact. Within the concept of terroir, climate is a factor that influences ripening of a specific variety and resulting wine style. Furthermore, the effect of soil on grape potential is complex, because the soil acts on grapevine water and nutrient supply, and influences root zone temperature. The aim of this work was to evaluate the effect of climate change (increased CO2, higher temperature and lower relative humidity), soil texture and irrigation on the physiology, yield and berry quality of grapevine (Vitis vinifera L.) cv. Tempranillo. A greenhouse experiment was carried out with potted, own-rooted fruit-bearing cuttings. Three factors were studied: a) climate change (700 μmol CO2 mol-1 air, 28/18°C and 45/65% day/night relative humidity) vs. current conditions (375 μmol CO2 mol-1 air, 24/14ºC and 33/53% day/night relative humidity), b) soil texture (9, 18 and 36% soil clay content) and c) irrigation; well-irrigated (20-35% of soil water content) vs. water deficit (60% of the water applied to the irrigated plants). Berries were harvested at ripeness (21-23 ºBrix). Climate change shortened the time between veraison and full maturity up to 9 days and reduced the number of berries per bunch. Grapes grown under climate change conditions had higher pH and lower acidity (due to malic and tartaric acids), anthocyanins content and colour intensity. Water-deficit delayed ripening up to 10 days and reduced final leaf area and root weight. Berries from water stressed plants had an increased skin/pulp ratio and pH, and lower acidity (malic acid) and polyphenol content. Regarding soil texture, plants grown in the soil with lower clay content increased root fresh weight and had higher total anthocyanins content. There were no interactions between factors. In conclusion, both climate change and water-deficit had a clear influence on the grape phenological development and composition, whilst soil affected root configuration and anthocyanins concentration. Effects of climate change and water availability on different soil conditions should be considered to take full advantage or mitigate the consequences of the future climate conditions.

Impact of water quality and irrigation management on soil salinization in the Drâa valley of Morocco.

NASA Astrophysics Data System (ADS)

Beff, L.; Descamps, C.; Dufey, J.; Bielders, C.

2009-04-01

Under the arid climatic conditions of the Drâa valley in southern Morocco, irrigation is essential for crop production. Two sources of water are available to farmers: (1) moderate salinity water from the Oued Drâa (classified as C3-S1 in the USDA irrigation water classification diagram) which is available only a few times per year following discrete releases from the Mansour Eddahbi dam, and (2) high salinity water from wells (C4-S2). Soil salinization is frequently observed, principally on plots irrigated with well water. As Oued water is available in insufficient amounts, strategies must be devised to use well and Oued water judiciously, without inducing severe salinization. The salinization risk under wheat production was evaluated using the HP1 program (Jacques and Šimůnek, 2005) for different combinations of the two main water sources, different irrigation frequencies and irrigation volumes. The soil was a sandy clay loam (topsoil) to sandy loam (40 cm depth). Soil hydrodynamic properties were derived from in situ measurements and lab measurements on undisturbed soil samples. The HP1 model was parameterized for wheat growth and 12 scenarios were run for 10 year periods using local climatic data. Water quality was measured or estimated on the basis of water samples in wells and various Oueds, and the soil chemical properties were determined. Depending on the scenario, soil salinity in the mean root zone increased from less than 1 meq/100g of soil to more than 5 meq/100g of soil over a ten year period. Salt accumulation was more pronounced at 45 cm soil depth, which is half of the maximum rooting depth, and when well water was preferentially used. Maximum crop yield (water transpired / potential water transpired) was achieved for five scenarios but this implied the use of well water to satisfy the crop water requirements. The usual Drâa Valley irrigation scenario, with five, 84 mm dam water applications per year, lead to a 25% yield loss. Adding the amount of well water needed to satisfy the crop water requirements as well as the leaching requirement had the lowest impact on soil salinization but resulted in a very low water use efficiency of 0.2 (water transpired / water added). This demonstrates the importance of using larger amounts of water than plant water requirements in this region in order to leach out salt of the root zone. However, in arid region, water is often limited and thus farmers can not afford to waste it. In that case, it is necessary to find a compromise between salinization, sodification and saving water. References: Jacques D., Šimůnek J. (2005). User Manual of the Multicomponent Variably-Saturated Flow and Transport Model HP1. Waste and Disposal Department, Mol, Belgium. USDA, United States Department of Agriculture (1969). Diagnosis and Improvement of Saline and Alkali Soils. United States Salinity Laboratory Staff, Agriculture Handbook No. 60, 160p.

Histological study of the effect of some irrigating solutions on bacterial endotoxin in dogs.

PubMed

Silva, Léa Assed Bezerra da; Leonardo, Mario Roberto; Assed, Sada; Tanomaru Filho, Mário

2004-01-01

The aim of this study was to evaluate, histopathologically, the effectiveness of mechanical preparation of root canals using different irrigating solutions in dog teeth filled with LPS after pulpectomy. A total of 120 root canals of 6 mongrel dogs were filled with a solution of LPS after pulpectomy. The irrigating solutions used were saline, 1, 2.5, and 5% sodium hypochlorite, and 2% chlorhexidine. No irrigation was used in the control group. The animals were sacrificed after 60 days and the teeth were fixed and demineralized. Subsequently, serial 6-microm sections were stained with hematoxylin and eosin and Mallory's trichrome for histopathological analysis and Brown-Brenn for verification of bacterial contamination. Analysis showed that the inflammatory infiltrate was statistically less intense in the groups in which the root canals were irrigated with 5% sodium hypochlorite and 2% chlorhexidine. However, none of the irrigating solutions completely inactivated the harmful effects of LPS. Mechanical preparation associated with different irrigating solutions did not completely inactivate LPS.

[Effects of alternative furrow irrigation and nitrogen application rate on photosynthesis, growth, and yield of cucumber in solar greenhouse].

PubMed

Zhang, Liu-xia; Wang, Shu-zhong; Sui, Xiao-lei; Zhang, Zhen-xian

2011-09-01

This paper studied the effects of alternative furrow irrigation and nitrogen (N) application rate (no N, optimal N, and conventional N) on the photosynthesis, growth characteristics, yield formation, and fruit quality of cucumber (Cucumis sativus) cultivar Jinyu No. 5 in a solar greenhouse in winter-spring growth season and autumn-winter season. Under alternative furrow irrigation, the net photosynthetic rate of upper, middle, eand lower leaves was appreciably lower and the transpiration rate decreased significantly, and the transient water use efficiency of upper and middle leaves improved, as compared with those under conventional irrigation. Stomatal factor was the limiting factor of photosynthesis under alternative furrow irrigation. The photosynthesis and transient water use efficiency of functional leaves under alternative furrow irrigation increased with increasing N application rate. Comparing with conventional irrigation, alternative furrow irrigation decreased leaf chlorophyll content and plant biomass, but increased root biomass, root/shoot ratio, and dry matter allocation in root and fruit. The economic output under alternative furrow irrigation was nearly the same as that under conventional irrigation, whereas the water use efficiency for economic yield increased significantly, suggesting the beneficial effects of alternative furrow irrigation on root development and fruit formation. With the increase of N application rate, the leaf chlorophyll content, chlorophyll a/b, specific leaf mass, plant biomass, economic yield, and fruit Vc and soluble sugar contents under alternative furrow irrigation increased, but no significant difference was observed between the treatments optimal N and conventional N. N application had little effects on the water use efficiency for economic yield. The economic yield and biomass production of the cucumber were significantly higher in winter-spring growth season than in autumn-winter growth season.

Confocal laser scanning, scanning electron, and transmission electron microscopy investigation of Enterococcus faecalis biofilm degradation using passive and active sodium hypochlorite irrigation within a simulated root canal model.

PubMed

Mohmmed, Saifalarab A; Vianna, Morgana E; Penny, Matthew R; Hilton, Stephen T; Mordan, Nicola; Knowles, Jonathan C

2017-08-01

Root canal irrigation is an important adjunct to control microbial infection. The aim of this study was to investigate the effect of 2.5% (wt/vol) sodium hypochlorite (NaOCl) agitation on the removal, killing, and degradation of Enterococcus faecalis biofilm. A total of 45 root canal models were manufactured using 3D printing with each model comprising an 18 mm length simulated root canal of apical size 30 and taper 0.06. E. faecalis biofilms were grown on the apical 3 mm of the models for 10 days. A total of 60 s of 9 ml of 2.5% NaOCl irrigation using syringe and needle was performed, the irrigant was either left stagnant in the canal or agitated using manual (Gutta-percha), sonic, and ultrasonic methods for 30 s. Following irrigation, the residual biofilms were observed using confocal laser scanning, scanning electron, and transmission electron microscopy. The data were analyzed using one-way ANOVA with Dunnett post hoc tests at a level of significance p ≤ .05. Consequence of root canal irrigation indicate that the reduction in the amount of biofilm achieved with the active irrigation groups (manual, sonic, and ultrasonic) was significantly greater when compared with the passive and untreated groups (p < .05). Collectively, finding indicate that passive irrigation exhibited more residual biofilm on the model surface than irrigant agitated by manual or automated (sonic, ultrasonic) methods. Total biofilm degradation and nonviable cells were associated with the ultrasonic group. © 2017 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Evaluation of the antimicrobial effect of super-oxidized water (Sterilox®) and sodium hypochlorite against Enterococcus faecalis in a bovine root canal model

PubMed Central

ROSSI-FEDELE, Giampiero; de FIGUEIREDO, José Antonio Poli; STEIER, Liviu; CANULLO, Luigi; STEIER, Gabriela; ROBERTS, Adam P.

2010-01-01

Ideally root canal irrigants should have, amongst other properties, antimicrobial action associated with a lack of toxicity against periapical tissues. Sodium hypochlorite (NaOCl) is a widely used root canal irrigant, however it has been shown to have a cytotoxic effect on vital tissue and therefore it is prudent to investigate alternative irrigants. Sterilox's Aquatine Alpha Electrolyte® belongs to the group of the super-oxidized waters; it consists of a mixture of oxidizing substances, and has been suggested to be used as root canal irrigant. Super-oxidized waters have been shown to provide efficient cleaning of root canal walls, and have been proposed to be used for the disinfection of medical equipment. Objective To compare the antimicrobial action against Enterococcus faecalis of NaOCl, Optident Sterilox Electrolyte Solution® and Sterilox's Aquatine Alpha Electrolyte® when used as irrigating solutions in a bovine root canal model. Methodology Root sections were prepared and inoculated with E. faecalis JH2-2. After 10 days of incubation the root canals were irrigated using one of three solutions (NaOCl, Optident Sterilox Electrolyte Solution® and Sterilox's Aquatine Alpha Electrolyte®) and subsequently sampled by grinding dentin using drills. The debris was placed in BHI broth and dilutions were plated onto fresh agar plates to quantify growth. Results Sodium hypochlorite was the only irrigant to eliminate all bacteria. When the dilutions were made, although NaOCl was still statistically superior, Sterilox's Aquatine Alpha Electrolyte® solution was superior to Optident Sterilox Electrolyte Solution®. Conclusion Under the conditions of this study Sterilox's Aquatine Alpha Electrolyte® appeared to have significantly more antimicrobial action compared to the Optident Sterilox Electrolyte Solution® alone, however NaOCl was the only solution able to consistently eradicate E. faecalis in the model. PMID:21085808

Water movement through thick unsaturated zones overlying the central High Plains aquifer, southwestern Kansas, 2000-2001

USGS Publications Warehouse

McMahon, Peter B.; Dennehy, K.F.; Michel, R.L.; Sophocleous, M.A.; Ellett, K.M.; Hurlbut, D.B.

2003-01-01

The role of irrigation as a driving force for water and chemical movement to the central High Plains aquifer is uncertain because of the thick unsaturated zone overlying the aquifer. Water potentials and profiles of tritium, chloride, nitrate, and pesticide concentrations were used to evaluate water movement through thick unsaturated zones overlying the central High Plains aquifer at three sites in southwestern Kansas. One site was located in rangeland and two sites were located in areas dominated by irrigated agriculture. In 2000?2001, the depth to water at the rangeland site was 50 meters and the depth to water at the irrigated sites was about 45.4 meters. Irrigation at the study sites began in 1955?56. Measurements of matric potential and volumetric water content indicate wetter conditions existed in the deep unsaturated zone at the irrigated sites than at the rangeland site. Total water potentials in the unsaturated zone at the irrigated sites systematically decreased with depth to the water table, indicating a potential existed for downward water movement from the unsaturated zone to the water table at those sites. At the rangeland site, total water potentials in the deep unsaturated zone indicate small or no potential existed for downward water movement to the water table. Postbomb tritium was not detected below a depth of 1.9 meters in the unsaturated zone or in ground water at the rangeland site. In contrast, postbomb tritium was detected throughout most of the unsaturated zone and in ground water at both irrigated sites. These results indicate post-1953 water moved deeper in the unsaturated zone at the irrigated sites than at the rangeland site. The depth of the interface between prebomb and postbomb tritium and a tritium mass-balance method were used to estimate water fluxes in the unsaturated zone at each site. The average water fluxes at the rangeland site were 5.4 and 4.4 millimeters per year for the two methods, which are similar to the average water flux (5.1 millimeters per year) estimated using a chloride mass-balance method. Tritium profiles in the unsaturated zone at the irrigated sites were complicated by the presence of tritium-depleted intervals separating upper and lower zones containing postbomb tritium. If the interface between prebomb and postbomb tritium was at the top of the tritium-depleted interval and postbomb tritium detected beneath that interval was from the declining water table in the area, then the average water flux at the irrigated sites was estimated to be 21 to 54 millimeters per year. If postbomb tritium detected beneath the tritium-depleted interval was from bypass or preferential water movement through the local unsaturated zone instead of the declining water table, then the minimum water flux at the irrigated sites was estimated to be 106 to 116 millimeters per year. In either case, water fluxes at the irrigated sites were at least 4 to 12 times larger than the flux at the rangeland site, indicating irrigation was an important driving force for water movement through the unsaturated zone. The presence of postbomb tritium and large nitrate and total pesticide concentrations (24 milligrams per liter as nitrogen and 0.923 microgram per liter, respectively) in ground water at the irrigated sites indicates irrigation water also was an important driving force for chemical movement to the water table. The persistence of a downward hydraulic gradient from the deep unsaturated zone to the water table at the irrigated sites, in addition to large nitrate and atrazine concentrations in deep soil water (34 milligrams per liter as nitrogen and 0.79 microgram per liter, respectively), indicate that the deep unsaturated zone will be a source of nitrate and atrazine to the aquifer in the future.

Influence of irrigation protocols on the bond strength of fiber posts cemented with a self-adhesive luting agent 24 hours after endodontic treatment.

PubMed

Lima, Jessica Ferraz Carvalho; Lima, Adriano Fonseca; Humel, Maria Malerba Colombi; Paulillo, Luis Alexandre Maffei Sartini; Marchi, Giselle Maria; Ferraz, Caio Cezar Randi

2015-01-01

The aim of this in vitro study was to evaluate the influence of different irrigation protocols on the bond strength, at different root depths, of fiber posts cemented with a self-adhesive cement 24 hours after endodontic treatment. Fifty-six bovine incisor roots were endodontically prepared and separated into 7 groups (n = 8) according to irrigation protocols: group 1, sterile saline (control); group 2, chlorhexidine (CHX) gel 2% and saline; group 3, sodium hypochlorite (NaOCl) 5.25% and saline; group 4, CHX and saline (final irrigation with ethylenediaminetetraacetic acid [EDTA] 17%); group 5, NaOCl and saline (final irrigation with EDTA); group 6, CHX and saline (final irrigation with NaOCl and EDTA); and group 7, NaOCl (final irrigation with CHX and EDTA). No statistically significant difference was found among the groups. Within the limitations of this study, it can be concluded that the different irrigation protocols did not influence the bond strength of self-adhesive resin cement, which presented similar behaviors at the 3 root depths studied.

Does endodontic post space irrigation affect smear layer removal and bonding effectiveness?

PubMed

Gu, Xin-Hua; Mao, Cai-Yun; Liang, Cong; Wang, Hui-Ming; Kern, Matthias

2009-10-01

The effect of different post space irrigants on smear layer removal and dentin bond strength was evaluated. Sixty-six extracted sound maxillary central incisors were endodontically treated. After post space preparation, the teeth were assigned to three groups of 22 teeth each. The teeth of these three groups were irrigated for 1 min with 17% ethylenediaminetetracetic acid (EDTA) (group 1), 5.25% sodium hypochlorite (NaOCl) (group 2), or 0.9% sodium chloride (NaCl) (group 3). In each group, eight specimens were split longitudinally for smear layer evaluation, and the other fourteen specimens were filled with a self-etching adhesive system (Panavia F). Four of 14 specimens of each group were prepared for evaluation of the resin-dentin interdiffusion zone (RDIZ) and resin tags, and the other 10 specimens were serially sectioned for push-out test analysis. Smear layer removal and bond strength were affected by different post space irrigants. EDTA removed the smear layer extremely effectively and, as a result, improved the bond strength at each region (apical, middle, and coronal) of the roots. Resin tag formation and the RDIZ were also affected by different irrigants and in accordance with bond strength. Therefore, removal of the smear layer use a self-etching luting system plays an important role in bonding effectiveness.

A comparative study of the debridement efficacy and apical extrusion of dynamic and passive root canal irrigation systems

PubMed Central

2014-01-01

Background Root canal irrigation carries a risk of extrusion of irrigant into the periapical tissues which can be associated with pain, swelling, and tissue damage. Studies have shown less extrusion with sonic or apical negative pressure devices compared with syringe and side-port needle or passive ultrasonic irrigation with continuous irrigant flow. This study aimed to evaluate the effectiveness of the EndoVac irrigation system, regarding 1) debris removal and 2) the control of apically extruded irrigating solution. Methods Fifty extracted human single-rooted teeth were used in this study. The teeth were then randomly divided into three experimental groups according to the type of irrigation used and one control group. In group 1, irrigation was performed using the EndoVac irrigation system. In group 2, irrigation was performed using a 30-gauge, tip-vented irrigation needle. In group 3, irrigation was performed using a 30-gauge, side-vented irrigation needle. The control group received instrumentation with no irrigation to serve as a control for cleaning efficiency. Root canal instrumentation was performed using the Profile NiTi rotary system with a crown-down technique. All of the experimental teeth were irrigated with the same amount of 5.25% sodium hypochlorite. The amount of extruded irrigating solution was then measured by subtracting the post-instrumentation weight from the pre-instrumentation weight using an electronic balance. The cleanliness of debris removal was evaluated using scanning electron microscopy. Results EndoVac irrigation had the least amount of extrusion followed by the side-vented and tip-vented method. The difference between the groups was statistically significant (P <0.01). As for the cleaning results, the debris collection in the EndoVac and tip-vented groups was the least in the apical third. In the control and the side-vented groups, the debris was the greatest in the apical third, but this difference was not significant among the three experimental groups. Conclusions The EndoVac irrigation system extruded significantly less irrigant solution than either needle irrigation system. Debris collection was the least in the apical third for the EndoVac irrigation system. No significant difference was found in the cleaning efficiency among the three irrigation systems. PMID:24512441

Scanning Electron Microscopic Evaluation of Root Canal Irrigation with Saline, Sodium Hypochlorite, and Citric Acid,

DTIC Science & Technology

1983-12-01

with six different irrigation regimens. Sodium hypochlorite (NaOCl) was significantly more effective than citric acid in "* removing superficial...EVALUATION OF ROOT CANAL IRRIGATION WITH SALINE, SODIUM HYPOCHLORITE , AND CITRIC ACID 4 *J. Craig Baumgartner, D.D.S., M.S. • **Carolyn M. Brown, D.D.S., M.S...preparation with six different irrigation regimens. Sodium hypochlorite (NaOCl) was significantly more effective than citric acid in removing superficial

Modeling and assessing field irrigation water use in a canal system of Hetao, upper Yellow River basin: Application to maize, sunflower and watermelon

NASA Astrophysics Data System (ADS)

Ren, Dongyang; Xu, Xu; Hao, Yuanyuan; Huang, Guanhua

2016-01-01

Water saving in irrigation is a key issue in the upper Yellow River basin. Excessive irrigation leads to water waste, water table rising and increased salinity. Land fragmentation associated with a large dispersion of crops adds to the agro-hydrological complexity of the irrigation system. The model HYDRUS-1D, coupled with the FAO-56 dual crop coefficient approach (dualKc), was applied to simulate the water and salt movement processes. Field experiments were conducted for maize, sunflower and watermelon crops in the command area of a typical irrigation canal system in Hetao Irrigation District during 2012 and 2013. The model was calibrated and validated in three crop fields using two-year experimental data. Simulations of soil moisture, salinity concentration and crop yield fitted well with the observations. The irrigation water use was then evaluated and results showed that large amounts of irrigation water percolated due to over-irrigation but their reuse through capillary rise was also quite large. That reuse was facilitated by the dispersion of crops throughout largely fragmented field, thus with fields reusing water percolated from nearby areas due to the rapid lateral migration of groundwater. Beneficial water use could be improved when taking this aspect into account, which was not considered in previous researches. The non-beneficial evaporation and salt accumulation into the root zone were found to significantly increase during non-growth periods due to the shallow water tables. It could be concluded that when applying water saving measures, close attention should be paid to cropping pattern distribution and groundwater control in association with irrigation scheduling and technique improvement.

Factors affecting irrigant extrusion during root canal irrigation: a systematic review.

PubMed

Boutsioukis, C; Psimma, Z; van der Sluis, L W M

2013-07-01

The aim of the present study was to conduct a systematic review and critical analysis of published data on irrigant extrusion to identify factors causing, affecting or predisposing to irrigant extrusion during root canal irrigation of human mature permanent teeth. An electronic search was conducted in Cochrane Library, LILACS, PubMed, SciELO, Scopus and Web of Knowledge using a combination of the terms 'irrigant', 'rinse', 'extrusion', 'injection', 'complication', 'accident', 'iatrogenic', 'root canal', 'tooth' and 'endodontic'. Additional studies were identified by hand-searching of six endodontic journals and the relevant chapters of four endodontic textbooks, resulting in a total of 460 titles. No language restriction was imposed. After applying screening and strict eligibility criteria by two independent reviewers, 40 case reports and 10 ex vivo studies were included in the review. A lack of clinical studies focusing on irrigant extrusion during root canal irrigation was evident. The reviewed case reports focused mainly on the clinical manifestations and management of the accidents and did not provide adequate details on the possible factors that may influence irrigant extrusion. The data from the included ex vivo studies were inconclusive due to major methodological limitations, such as not simulating the presence of periapical tissues and not assessing the validity of irrigant detection methods. The extensive variability in the protocols employed hindered quantitative synthesis. The choice of factors investigated in ex vivo studies seems not to have been driven by the available clinical evidence. These issues need to be addressed in future studies. © 2012 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Efficacy of different irrigation regimes on the push-out bond strength of various resin-based sealers at different root levels: An in vitro study.

PubMed

Verma, Diksha; Taneja, Sonali; Kumari, Manju

2018-01-01

This study aims to evaluate and compare the efficacy of various irrigation regimens on push-out bond strength of AH Plus/gutta-percha, Real Seal/Resilon, and MetaSeal/gutta-percha at three different root levels. Single-rooted mandibular premolars ( n = 120) were prepared and divided into four groups ( n = 30) based on irrigation regimen used: I: 5.25% sodium hypochlorite (NaOCl)-17% ethylenediaminetetraacetic acid (EDTA); II: 5.25% NaOCl-2.25% Peracetic acid (PAA); III: 5.25% NaOCl-18% 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) (Etidronic Acid); and IV: Distilled Water. Each group was further divided into three subgroups ( n = 10); A: AH Plus/gutta-percha; B: MetaSEAL/gutta-percha; C: RealSeal/Resilon. After obturation, roots were sectioned at 3 levels and push-out tests were performed. One-way ANOVA with post hoc Tukey-honestly significant difference tests were applied to assess the significance among various groups. Among irrigants, 2.25% PAA showed significantly lower values when compared with rest of the irrigants. There was no significant difference found among EDTA and HEBP. The push-out bond strength of AH Plus was significantly higher among all sealers. The bond strength values were significantly decreased in apico-coronal direction. There was superior efficacy of EDTA and HEBP on the bond strength of AH Plus at apical root level when compared with other irrigants and sealers at various root levels.

Apical pressure created during irrigation with the GentleWave™ system compared to conventional syringe irrigation.

PubMed

Haapasalo, Markus; Shen, Ya; Wang, Zhejun; Park, Ellen; Curtis, Allison; Patel, Payal; Vandrangi, Prashanthi

2016-09-01

The purpose of this study is to compare pressures at the apical foramen created by conventional syringe irrigation and the GentleWave™ System, which releases high-velocity degassed irrigants to the pulp chamber and uses broad-spectrum sound energy for cleaning. The apical pressure generated during irrigation was measured for palatal and distobuccal root canals of four extracted maxillary molars after no instrumentation, minimal instrumentation to a size #15/.04, instrumentation to a size #40/.04 taper, and after perforating the apical foramen to size #40. The root canals opened into an air-tight custom fixture coupled to a piezoresistive pressure transducer. Apical pressures were measured for the GentleWave™ System and syringe-needle irrigation at different irrigant flow rates, with the needle tip at 1 and 3 mm from the apical foramen using 30-gauge (G) open-ended or side-vented safety tip needles. The GentleWave™ System generated negative apical pressures (P < 0.001 compared with syringe irrigation); the mean pressures were between -13.07 and -17.19 mmHg. The 30 G needles could not reach the 1 and 3 mm from the working length in uninstrumented and 1 mm in minimally instrumented canals. The mean positive pressures between 6.46 and 110.34 mmHg were measured with needle irrigation depending on the flow rate, needle insertion depth, and size of the root canal. The GentleWave™ System creates negative pressure at the apical foramen during root canal cleaning irrespective of the size of canal instrumentation. Positive apical pressures were measured for syringe irrigation. Negative pressure during irrigation contributes to improved safety as compared to high-positive pressure.

Release of Growth Factors into Root Canal by Irrigations in Regenerative Endodontics.

PubMed

Zeng, Qian; Nguyen, Sean; Zhang, Hongming; Chebrolu, Hari Priya; Alzebdeh, Dalia; Badi, Mustafa A; Kim, Jong Ryul; Ling, Junqi; Yang, Maobin

2016-12-01

The aim of this study was to investigate the release of growth factors into root canal space after the irrigation procedure of regenerative endodontic procedure. Sixty standardized root segments were prepared from extracted single-root teeth. Nail varnish was applied to all surfaces except the root canal surface. Root segments were irrigated with 1.5% NaOCl + 17% EDTA, 2.5% NaOCl + 17% EDTA, 17% EDTA, or deionized water. The profile of growth factors that were released after irrigation was studied by growth factor array. Enzyme-linked immunosorbent assay was used to validate the release of transforming growth factor (TGF)-β1 and basic fibroblast growth factor (bFGF) at 4 hours, 1 day, and 3 days after irrigation. The final concentrations were calculated on the basis of the root canal volume measured by cone-beam computed tomography. Dental pulp stem cell migration on growth factors released from root segments was measured by using Transwell assay. Total of 11 of 41 growth factors were detected by growth factors array. Enzyme-linked immunosorbent assay showed that TGF-β1 was released in all irrigation groups. Compared with the group with 17% EDTA (6.92 ± 4.49 ng/mL), the groups with 1.5% NaOCl + 17% EDTA and 2.5% NaOCl + 17% EDTA had significantly higher release of TGF-β1 (69.04 ± 30.41 ng/mL and 59.26 ± 3.37 ng/mL, respectively), with a peak release at day 1. The release of bFGF was detected at a low level in all groups (0 ng/mL to 0.43 ± 0.22 ng/mL). Migration assay showed the growth factors released from root segments induced dental pulp stem cell migration. The root segment model in present study simulated clinical scenario and indicated that the current irrigation protocol released a significant amount of TGF-β1 but not bFGF. The growth factors released into root canal space induced dental pulp stem cell migration. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Efficacy of laser-driven irrigation versus ultrasonic in removing an airlock from the apical third of a narrow root canal.

PubMed

Peeters, Harry Huiz; Gutknecht, Norbert

2014-08-01

The purpose of the study was to test the hypothesis that air entrapment occurs in the apical third of a root canal during irrigation. A second objective was to test the null hypothesis that there is no difference between laser-driven irrigation (an erbium, chromium:yttrium-scandium-gallium-garnet laser) and passive ultrasonic irrigation in removing an airlock from the apical third. One hundred twenty extracted human teeth with single narrow root canals were randomised into two experimental groups (n = 40) and two control groups (n = 20). The specimens were shaped using hand instruments up to a size 30/0.02 file. The teeth were irrigated with a mixture of saline, radiopaque contrast and ink in solution. In the passive ultrasonic irrigation group, the irrigant was activated with an ultrasonic device for 60 s. In the laser group, the irrigant was activated with a laser for 60 s. It was concluded that if the insertion of irrigation needle is shorter than the working length, air entrapment may develop in the apical third, but the use of laser-driven irrigation is completely effective in removing it. © 2013 The Authors. Australian Endodontic Journal © 2013 Australian Society of Endodontology.

The effect of ultrasonic post instrumentation on root surface temperature.

PubMed

Huttula, Andrew S; Tordik, Patricia A; Imamura, Glen; Eichmiller, Frederick C; McClanahan, Scott B

2006-11-01

This study measured root surface temperature changes when ultrasonic vibration, with and without irrigation, was applied to cemented endodontic posts. Twenty-six, extracted, single-rooted premolars were randomly divided into two groups. Root lengths were standardized, canals instrumented, obturated, and posts cemented into prepared spaces. Thermocouples were positioned at two locations on the proximal root surfaces. Samples were embedded in plaster and brought to 37 degrees C in a water bath. Posts were ultrasonically vibrated for 4 minutes while continuously measuring temperature. Two-way ANOVA compared effects of water coolant and thermocouple location on temperature change. Root surface temperatures were significantly higher (p < 0.001) when posts were instrumented dry. A trend for higher temperatures was observed at coronal thermocouples of nonirrigated teeth and at apical thermocouples of irrigated teeth (p = 0.057). Irrigation during post removal with ultrasonics had a significant impact on the temperature measured at the external root surface.

Comparative Effectiveness of New Mechanical Irrigant Agitating Devices for Debris Removal from the Canal and Isthmus of Mesial Roots of Mandibular Molars.

PubMed

Duque, Jussaro Alves; Duarte, Marco Antonio Hungaro; Canali, Lyz Cristina Furquim; Zancan, Rafaela Fernandes; Vivan, Rodrigo Ricci; Bernardes, Ricardo Affonso; Bramante, Clovis Monteiro

2017-02-01

The aim of this study was to compare the effectiveness of Easy Clean (Easy Dental Equipment, Belo Horizonte, MG, Brazil) in continuous and reciprocating motion, passive ultrasonic irrigation (PUI), Endoactivator systems (Dentsply Maillefer, Ballaigues, Switzerland), and conventional irrigation for debris removal from root canals and isthmus. Fifty mesial roots of mandibular molars were embedded in epoxy resin using a metal muffle; afterward, the blocks containing the roots were sectioned at 2, 4, and 6 mm from the apex. After instrumentation, the roots were divided into 5 groups (n = 10) for application of the final irrigation protocol using Easy Clean in continuous rotation, Easy Clean in reciprocating motion, PUI, Endoactivator, and conventional irrigation. Scanning electron microscopic images were taken after instrumentation and after the first, second, and third activation of irrigating solution to evaluate the area of remaining debris with image J software (National Institutes of Health, Bethesda, MD). The protocol of 3 irrigating solution activations for 20 seconds provided better cleaning of the canal and isthmus. On conclusion of all procedures, analysis of the canals showed a statistical difference only at 2 mm; the Easy Clean in continuous rotation was more efficient than conventional irrigation (P < .05). On conclusion of all steps, the largest difference was observed in the isthmus in which the Easy Clean in continuous rotation was more effective than conventional irrigation at the 3 levels analyzed and the Endoactivator at 4 mm (P < .05). The PUI promoted greater cleaning than conventional irrigation at 6 mm (P < .05). There was no statistical difference between Easy Clean in continuous rotation, Easy Clean in reciprocating motion, and PUI (P > .05). Irrigating solution activation methods provided better cleaning of the canal and isthmus, especially the Easy Clean used in continuous rotation. The protocol of 3 irrigating solution activations for 20 seconds favored better cleaning. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Farm scale application of EMI and FDR sensors to measuring and mapping soil water content

NASA Astrophysics Data System (ADS)

Rallo, Giovanni; Provenzano, Giuseppe

2017-04-01

Soil water content (SWC) controls most water exchange processes within and between the soil-plants-atmosphere continuum and can therefore be considered as a practical variable for irrigation farmer choices. A better knowledge of spatial SWC patterns could improve farmer's awareness about critical crop water status conditions and enhance their capacity to characterize their behavior at the field or farm scale. However, accurate soil moisture measurement across spatial and temporal scales is still a challenging task and, specifically at intermediate spatial (0.1-100 ha) and temporal (minutes to days) scales, a data gap remains that limits our understanding over reliability of the SWC spatial measurements and its practical applicability in irrigation scheduling. In this work we compare the integrated EM38 (Geonics Ltd. Canada) response, collected at different sensor positions above ground to that obtained by integrating the depth profile of volumetric SWC measured with Diviner 2000 (Sentek) in conjunction with the depth response function of the EM38 when operated in both horizontal and vertical dipole configurations. On a 1.0-ha Olive grove site in Sicliy (Italy), 200 data points were collected before and after irrigation or precipitation events following a systematic sampling grid with focused measurements around the tree. Inside two different zone of the field, characterized from different soil physical properties, two Diviner 2000 access tube (1.2 m) were installed and used for the EM38 calibration. After calibration, the work aimed to propose the combined use of the FDR and EMI sensors to measuring and mapping root zone soil water content. We found strong correlations (R2 = 0.66) between Diviner 2000 SWC averaged to a depth of 1.2 m and ECa from an EM38 held in the vertical mode above the soil surface. The site-specific relationship between FDR-based SWC and ECa was linear for the purposes of estimating SWC over the explored range of ECa monitored at field levels. Volumetric SWC changes in the root zone were observed by differencing the maps, where differences in the observed ECa are primarily the result of changes in soil water status. As with the data showed in the research, more structured patterns occur after wetting event, indicating the presence of subsurface flow or root water uptake paths. A vision for the future at hydrological watershed scale is to combine EMI measurements with FDR-based sensor networks, the last with the scope to constrain calibration of the EMI measurements.

Comparison of the EndoVac system to needle irrigation of root canals.

PubMed

Nielsen, Benjamin A; Craig Baumgartner, J

2007-05-01

Past studies have shown that current irrigation methods are effective at cleaning root canals coronally but less effective apically. To be effective, endodontic irrigants should ideally be delivered near working length. The purpose of this study was to compare the efficacy of the EndoVac irrigation system and needle irrigation to debride root canals at 1 and 3 mm from working length. One tooth of each matched pair was instrumented and irrigated by using the EndoVac, which uses negative pressure to deliver irrigating solutions to working length. The other tooth of the matched pair was instrumented and irrigated with a 30-gauge ProRinse irrigating needle. All teeth were irrigated with sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) for a predetermined amount of time, and total volume of irrigant used was recorded. After instrumentation and irrigation, the teeth were fixed, decalcified, and sectioned at 1 mm and 3 mm from working length. Serial sections were made and digitally photographed. The amount of remaining debris was determined as a percentage of the area of the canal lumen. Remaining debris and total irrigant were analyzed by using the Wilcoxon signed rank test at the 5% confidence level. At the 1-mm level, significantly less debris was found in the EndoVac group (p=0.0347). At the 3-mm level, there was no significant difference between groups. Significantly more irrigant was delivered with the EndoVac (p<0001). This study showed significantly better debridement at 1 mm from working length by using the EndoVac compared with needle irrigation.

Transpiration Driven Hydrologic Transport in vegetated shallow water environments: Implications on Diel and Seasonal Soil Biogeochemical Processes and System Management

NASA Astrophysics Data System (ADS)

Bachand, P.; Bachand, S. M.; Fleck, J.; Anderson, F.

2011-12-01

Hydrology arguably plays the most important role in biogeochemical cycling of mercury in wetlands and other shallow aquatic systems. CFSTR, PFR and non-ideal reactor models are oftentimes currently used to hydrologically assess these systems and to account for the fate, transport and cycling of constituents of concern (COC) with systems assumed to be non-leaky and with diffusion dominating soil transport. Yet a number of results in the literature imply transpiration drives soil transport: transpiration into the root zone is in the range of 50 - 75% of ET seasonally; gaseous emissions from aquatic systems show a diel pattern that tracks diel ET patterns; in long detention time aquatic systems ET is the largest sink for applied surface waters; and non-reactive tracers when applied to surface waters can find themselves in the root zone and within plants. All these findings strongly suggest transpiration driven infiltration into the root zone, is a significant hydrologic pathway for constituents and is an important transport mechanism. This paper examines the annual water budget for four shallow aquatic land uses in the Yolo Bypass, California: rice, wild rice, fallowed fields and wetlands. Results indicate that differences in hydrology between the fields, particularly the temporal nature of transpiration, play a significant role in mercury transformations and transport. During the irrigation period, fallowed fields discharged 6 cm of surface water (15% applied water), rice fields 31 - 43 cm (27 - 31% applied water), and wild rice fields 16 - 39 cm (15 - 31% applied water). Evapotranspiration rates were in the range of 120 - 130 cm/y for all land uses (i.e. rice, wild rice, fallowed fields and seasonal wetlands) except for the permanent wetland which was about 1/3 higher at about 170 cm/y. During the summer, approximately 50% of the applied surface water was drawn into the root zone to meet transpiration demands. Based upon results from our water budget and utilizing modified Peclet No. calculations, we quantified the relative importance of upward diffusion from the sediments and downward advection from transpiration as hydrologic transport mechanisms in the root zone. Transpiration driven infiltration moves water past the diffusive zone within 1 - 2 days in this system during the summer months. With the waning seasons, evapotranspiration diminishes until by winter diffusion dominates throughout the entire root zone. This model has great implications on the analyses of soil biogeochemical process in the root zone of shallow aquatic systems. Downward advection is a major transport mechanism into the root zone of shallow flooded aquatic systems and provides an important physical mechanism that drives variability in the seasonal and diel storage; release and cycling of COCs; and the creation of both a physical and chemical barrierd to upward diffusion of soil-borne COCs into the water column. Models that do not account for root zone interactions may not be able to capture diel and seasonal differences. Moreover, these interactions may lead to unanticipated environmental consequences as a result of cultural practices.

Modeling the intersections of Food, Energy, and Water in climate-vulnerable Ethiopia with an application to small-scale irrigation

NASA Astrophysics Data System (ADS)

Zhang, Y.; Sankaranarayanan, S.; Zaitchik, B. F.; Siddiqui, S.

2017-12-01

Africa is home to some of the most climate vulnerable populations in the world. Energy and agricultural development have diverse impacts on the region's food security and economic well-being from the household to the national level, particularly considering climate variability and change. Our ultimate goal is to understand coupled Food-Energy-Water (FEW) dynamics across spatial scales in order to quantify the sensitivity of critical human outcomes to FEW development strategies in Ethiopia. We are developing bottom-up and top-down multi-scale models, spanning local, sub-national and national scales to capture the FEW linkages across communities and climatic adaptation zones. The focus of this presentation is the sub-national scale multi-player micro-economic (MME) partial-equilibrium model with coupled food and energy sector for Ethiopia. With fixed large-scale economic, demographic, and resource factors from the national scale computable general equilibrium (CGE) model and inferences of behavior parameters from the local scale agent-based model (ABM), the MME studies how shocks such as drought (crop failure) and development of resilience technologies would influence FEW system at a sub-national scale. The MME model is based on aggregating individual optimization problems for relevant players. It includes production, storage, and consumption of food and energy at spatially disaggregated zones, and transportation in between with endogenously modeled infrastructure. The aggregated players for each zone have different roles such as crop producers, storage managers, and distributors, who make decisions according to their own but interdependent objective functions. The food and energy supply chain across zones is therefore captured. Ethiopia is dominated by rain-fed agriculture with only 2% irrigated farmland. Small-scale irrigation has been promoted as a resilience technology that could potentially play a critical role in food security and economic well-being in Ethiopia, but that also intersects with energy and water consumption. Here, we focus on the energy usage for small-scale irrigation and the collective impact on crop production and water resources across zones in the MME model.

Comparison of sealer penetration using the EndoVac irrigation system and conventional needle root canal irrigation.

PubMed

Kara Tuncer, Aysun; Unal, Bayram

2014-05-01

The aim of this study was to compare the effect of the EndoVac irrigation system (SybronEndo, Orange, CA) and conventional endodontic needle irrigation on sealer penetration into dentinal tubules. Forty single-rooted, recently extracted human maxillary central incisors were randomly divided into 2 groups according to the irrigation technique used: conventional endodontic needle irrigation and EndoVac irrigation. All teeth were instrumented using the ProFile rotary system (Dentsply Maillefer, Ballaigues, Switzerland) and obturated with gutta-percha and AH Plus sealer (Dentsply DeTrey, Konstanz, Germany) labeled with fluorescent dye. Transverse sections at 1, 3, and 5 mm from the root apex were examined using confocal laser scanning microscopy. The total percentage and maximum depth of sealer penetration were then measured. Mann-Whitney test results showed that EndoVac irrigation resulted in a significantly higher percentage of sealer penetration than conventional irrigation at both the 1- and 3-mm levels (P < .05). However, no difference was found at the 5-mm level. The 5-mm sections in each group showed a significantly higher percentage and maximum depth of sealer penetration than did the 1- and 3-mm sections (P < .05). The EndoVac irrigation system significantly improved the sealer penetration at the 1- to 3-mm level over that of conventional endodontic needle irrigation. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Antibacterial efficacy of an endodontic sonic-powered irrigation system: An in vitro study.

PubMed

Zeng, Chang; Willison, Jon; Meghil, Mohamed M; Bergeron, Brian E; Cutler, Christopher W; Tay, Franklin R; Niu, Lina; Ma, Jingzhi

2018-06-13

To evaluate the efficacy of EDDY, a new sonic-powered irrigation system, in reducing intracanal bacteria load. Thirty-eight instrumented, autoclaved single-rooted human premolars were inoculated with Enterococcus faecalis (ATCC-29212) for 21 days. Two teeth were used as negative control without bacterial contamination. For the bacteria-inoculated teeth, 6 were used as positive control without irrigation. The remaining 30 teeth were randomly divided into 2 groups (N = 15), using 3% NaOCl as irrigant: (A) 30-gauge syringe needle irrigation (SNI), (B) EDDY (VDW, Munich, Germany). Twelve teeth per group and 4 teeth in the positive control were evaluated for bacterial reduction using MTT assay. The remaining teeth were split for BacLight LIVE/DEAD staining to examine the percentages of live/dead bacteria present in the dentinal tubules from different canal locations (coronal, mid-root and apical portions of the canal space) using confocal laser scanning microscopy (CLSM). MTT assay indicated that both SNI and EDDY significantly reduced overall intracanal bacterial load compared with the positive control, with no significant difference between the two techniques. CLSM indicated that EDDY had better intratubular bacterial killing efficacy than SNI in the coronal and mid-root portions of the canal space only but not in the apical portion. In all canal locations (coronal, mid-root apical), both systems failed to eliminate bacteria that proliferated deep within the dentinal tubules. With the use of 3% NaOCl, sonic-powered irrigant activation with EDDY tips did not provide additional advantage over SNI in killing Enterococcus faecalis from deep intraradicular dentin. Both the sonic-powered root canal irrigant activation system and syringe needle irrigation can reduce intracanal bacteria load but are incapable of completely killing all bacteria that resided deep within the dentinal tubules of root canals infected with Enterococcus faecalis. Published by Elsevier Ltd.

[Influence of different levels of irrigation and nitrogen application on the root growth and yield of spring wheat under permanent raised bed.

PubMed

Chen, Juan; Ma, Zhong Ming; Lyu, Xiao Dong; Liu, Ting Ting

2016-05-01

To establish an optimum combination of water and nitrogen for spring under permanent raised bed (PRB) tillage, a field investigation was carried out to assess effects of irrigation and N application on root growth, yield, irrigation water productivity and N efficiency. The experiment followed a completely randomized split-plot design, taking furrow irrigation 1200 m 3 ·hm -2 (W 1 ), 2400 m 3 ·hm -2 (W 2 ), 3600 m 3 ·hm -2 (W 3 ) as main plot treatments, and N rates (0, 90, 180, 270 kg·hm -2 ) the sub-plot treatments. Our results showed that the root mass density (RWD) was significantly affected by irrigation and N application, the RWD of spring wheat reached a maximum at the filling stage, followed by a slow decline until maturity, while the effect of N on RWD depended on soil water conditions. The application of N 2 produced the maximum RWD under W 2 irrigation, the application of N 1 produced the maximum RWD under W 1 irrigation, and the application of N 3 produced the maximum RWD under W 3 irrigation. The order of irrigation regime effect on RWD of spring wheat was W 2 >W 3 >W 1 . The order of irrigation regime and N rate effect on RWD of spring wheat was irrigation>N>irrigation and N interaction. W 2 N 2 treatment produced the highest RWD value. The root-to-shoot ratio (R/S) descended with the rising of irrigation water and nitrogen amount, and the combined treatment (W 1 N 0 ) produced the maximum R/S. The root system was mainly distributed in the 0-40 cm soil layer, in which the RWD accounted for 85% of the total RWD in 0-80 cm soil depth. There was a significantly positive relationship between RWD in the 0-40 cm and the yield of spring wheat, RWD in the 40-60 cm had higher linear dependence on the yield of spring wheat. W 2 increased the proportion of RWD in the deep soil layer (40-60 cm). The irrigation and N rate had a significant impact on biomass and grain yield of spring wheat, the biomass increased as the N rate and water amount increased, W 2 N 2 treatment produced the highest grain yield, irrigation water productivity descended with increasing the irrigation amount, and the nitrogen agronomic efficiency descended with increasing N rate. It was concluded that the irrigation level W 2 (2400 m 3 ·hm -2 ) and nitrogen level N 2 (180 kg·hm -2 ) could be recommended as the best combination of water and N, which promoted the root growth, improved grain yield, water and nitrogen use efficiencies of spring wheat production under PRB tillage in the experimental area.

Influence of irrigation and obturation techniques on artificial lateral root canal filling capacity.

PubMed

Silva, Emmanuel J; Herrera, Daniel R; Souza-Júnior, Eduardo J; Teixeira, João M

2013-01-01

The aim of this study was to evaluate the influence of two different irrigation protocols on artificial lateral root canal filling capacity using different obturation techniques. Sixty single-root human teeth were used. Two artificial lateral canals were created in the apical third. Root canals were instrumented up to a 45 K-file to the working length. Before each file, root canals were irrigated either with 2 mL of 2.5% NaOCl or 2% chlorhexidine gel with further irrigation with saline solution and 3 mL of 17% EDTA. Specimens were randomly divided into three groups according to the obturation technique: (1) lateral compaction technique; (2) Tagger hybrid technique; and (3) thermoplasticized technique using BeeFill 2 in 1. All groups used AH Plus as the root canal sealer. The specimens were decalcified and cleared in methyl salicylate. The total length of lateral canals was observed under X30 magnification with a stereomicroscope and measured on the buccal and lingual root surfaces using Leica IM50 software. The data were submitted to ANOVA and Tukey test (p < 0.05). Among the obturation techniques, BeeFill 2 in 1 showed deeper penetration into all lateral canals than the lateral compaction or Tagger hybrid techniques (p < 0.05). The lateral compaction group showed the worst results (p < 0.05). Irrigants did not affect the outcome; there was no difference between NaOCl and chlorhexidine when the same obturation technique was used (p > 0.05). Regardless of the irrigant used during endodontic procedures, the thermoplasticized techniques showed higher penetration behavior for filling artificial lateral canals than the lateral compaction technique.

Mesquite root distribution and water use efficiency in response to long-term soil moisture manipulations

Treesearch

R. J. Ansley; T. W. Boutton; P. W. Jacoby

2007-01-01

This study quantified honey mesquite (Prosopis glandulosa) root growth and water use efficiency following chronic soil drought or wetness on a clay loam site in north Texas. Root systems of mature trees were containerized with barriers inserted into the soil. Soil moisture within containers was manipulated with irrigation (Irrigated) or rain...

Continuous chelation irrigation improves the adhesion of epoxy resin-based root canal sealer to root dentine.

PubMed

Neelakantan, P; Varughese, A A; Sharma, S; Subbarao, C V; Zehnder, M; De-Deus, G

2012-12-01

To test the impact of continuous chelation by NaOCl+ etidronic acid (HEBP) during instrumentation, and a final rinse of EDTA or NaOCl + HEBP on the dentine bond strength of an epoxy resin sealer (AH Plus). Single-rooted teeth (n = 100) were divided into five groups (n = 20) based on the irrigation protocol and their root canals instrumented using a rotary Ni-Ti system: 2.5% NaOCl during instrumentation followed by bi-distilled water (G1) or 17% EDTA (G2) as final rinse; 1 : 1 mixture of 5% NaOCl and 18% HEBP during instrumentation, and the same mixture (G3), 17% EDTA (G4) or bi-distilled water (G5) as final rinse. Canals were filled with AH Plus. Roots were sectioned, and push-out tests were performed in coronal, middle and apical root thirds. Results were analysed using analysis of variance (anova) and Bonferroni test for multiple comparisons. The alpha-type error was set at 0.05 for all the analyses. Push-out bond strength was highest in coronal and lowest in apical root thirds (P < 0.05). Groups that used NaOCl + HEBP irrigation during instrumentation had significantly higher bond strengths than groups following the NaOCl-EDTA irrigation in all root thirds (P < 0.05). The use of a strong chelator as final flush further increased bond strengths (G4, P < 0.05). The continuous chelation irrigation protocol optimizes the bond strength of an epoxy resin sealer to dentine. © 2012 International Endodontic Journal.

Comparison of the Antimicrobial Efficacy of Octenidine Dihydrochloride and Chlorhexidine with and Without Passive Ultrasonic Irrigation - An Invitro Study.

PubMed

Cherian, Bastin; Gehlot, Paras Mull; Manjunath, Mysore Krishnaswamy

2016-06-01

Elimination of microorganisms from infected root canals is a complicated task. Numerous measures have been described to reduce the microbial load in the root canal system, including the use of various instrumentation techniques, irrigation regimens and intracanal medicaments. The drawbacks of few commonly used irrigants include toxic and harmful side effects, microbial resistance to antimicrobial agents and staining. Hence there is a need for alternative agents which are nontoxic, effective and safe. To compare and evaluate antimicrobial effects of 2% Chlorhexidine (CHX) versus 0.1% Octenidine Dihydrochloride (OCT) as root canal irrigant with and without passive ultrasonic irrigation against Enterococcus faecalis (E. faecalis) in vitro and to evaluate the depth of penetration of irrigant solution into the dentinal tubules at the junction of middle and apical third. Forty eight freshly extracted, single rooted human mandibular premolars were decoronated and root specimen standardized to 14mm. Biofilm of E. faecalis (strain ATCC 29212) was grown for seven days and the specimens were divided into four groups (n=12) based on irrigation protocol : Group I- Conventional Syringe Irrigation (CSI) with 2% CHX, Group II- CSI + 0.1% OCT, Group III-Passive Ultrasonic Irrigation (PUI) + 2% CHX and Group IV- PUI+ 0.1% OCT. Dentin shavings were collected at two depths (200μm and 400μm) and total number of colony forming units were determined. The data were statistically analyzed using ANOVA, Scheffes multiple comparison of means and paired t-test (p<0.05). Group III and IV (PUI) showed significant difference compared to Group I and II (CSI) both at 200μm and 400μm (p=0.000). For Group III and Group IV no significant differences were found at 200μm and 400μm (p=1.000 and 0.363 respectively), however significant difference was found between data at 200μm and 400μm for all the four groups (p=0.000). Octenidine (0.1%) was more effective than 2% Chlorhexidine against E. faecalis both at 200μm and 400μm. Passive ultrasonic irrigation proved to enhance the antimicrobial action of the irrigants.

Long range lateral root activity by neo-tropical savanna trees.

Treesearch

Leonel da S. L. Sternberg; Sandra Bucci; Augusto Franco; Guillermo Goldstein; William A. Hoffman; Frederick C. Meinzer; Marcelo Z. Moreira; Fabian Scholz

2004-01-01

The extent of water uptake by lateral roots of savanna trees in the Brazilian highlands was measured by irrigating two 2 by 2 m plots with deuterium-enriched water and assaying for the abundance of deuterium in stem water from trees inside and at several distances from the irrigation plots. Stem water of trees inside the irrigation plots was highly enriched compared to...

Efficacy of different irrigation regimes on the push-out bond strength of various resin-based sealers at different root levels: An in vitro study

PubMed Central

Verma, Diksha; Taneja, Sonali; Kumari, Manju

2018-01-01

Aim: This study aims to evaluate and compare the efficacy of various irrigation regimens on push-out bond strength of AH Plus/gutta-percha, Real Seal/Resilon, and MetaSeal/gutta-percha at three different root levels. Materials and Methods: Single-rooted mandibular premolars (n = 120) were prepared and divided into four groups (n = 30) based on irrigation regimen used: I: 5.25% sodium hypochlorite (NaOCl)-17% ethylenediaminetetraacetic acid (EDTA); II: 5.25% NaOCl-2.25% Peracetic acid (PAA); III: 5.25% NaOCl-18% 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) (Etidronic Acid); and IV: Distilled Water. Each group was further divided into three subgroups (n = 10); A: AH Plus/gutta-percha; B: MetaSEAL/gutta-percha; C: RealSeal/Resilon. After obturation, roots were sectioned at 3 levels and push-out tests were performed. One-way ANOVA with post hoc Tukey-honestly significant difference tests were applied to assess the significance among various groups. Results: Among irrigants, 2.25% PAA showed significantly lower values when compared with rest of the irrigants. There was no significant difference found among EDTA and HEBP. The push-out bond strength of AH Plus was significantly higher among all sealers. The bond strength values were significantly decreased in apico-coronal direction. Conclusions: There was superior efficacy of EDTA and HEBP on the bond strength of AH Plus at apical root level when compared with other irrigants and sealers at various root levels. PMID:29674811

Simulating the fate of water in field soil crop environment

NASA Astrophysics Data System (ADS)

Cameira, M. R.; Fernando, R. M.; Ahuja, L.; Pereira, L.

2005-12-01

This paper presents an evaluation of the Root Zone Water Quality Model(RZWQM) for assessing the fate of water in the soil-crop environment at the field scale under the particular conditions of a Mediterranean region. The RZWQM model is a one-dimensional dual porosity model that allows flow in macropores. It integrates the physical, biological and chemical processes occurring in the root zone, allowing the simulation of a wide spectrum of agricultural management practices. This study involved the evaluation of the soil, hydrologic and crop development sub-models within the RZWQM for two distinct agricultural systems, one consisting of a grain corn planted in a silty loam soil, irrigated by level basins and the other a forage corn planted in a sandy soil, irrigated by sprinklers. Evaluation was performed at two distinct levels. At the first level the model capability to fit the measured data was analyzed (calibration). At the second level the model's capability to extrapolate and predict the system behavior for conditions different than those used when fitting the model was assessed (validation). In a subsequent paper the same type of evaluation is presented for the nitrogen transformation and transport model. At the first level a change in the crop evapotranspiration (ETc) formulation was introduced, based upon the definition of the effective leaf area, resulting in a 51% decrease in the root mean square error of the ETc simulations. As a result the simulation of the root water uptake was greatly improved. A new bottom boundary condition was implemented to account for the presence of a shallow water table. This improved the simulation of the water table depths and consequently the soil water evolution within the root zone. The soil hydraulic parameters and the crop variety specific parameters were calibrated in order to minimize the simulation errors of soil water and crop development. At the second level crop yield was predicted with an error of 1.1 and 2.8% for grain and forage corn, respectively. Soil water was predicted with an efficiency ranging from 50 to 95% for the silty loam soil and between 56 and 72% for the sandy soil. The purposed calibration procedure allowed the model to predict crop development, yield and the water balance terms, with accuracy that is acceptable in practical applications for complex and spatially variable field conditions. An iterative method was required to account for the strong interaction between the different model components, based upon detailed experimental data on soils and crops.

[Evaluation of root canal isthmus debridement efficacy of Er:YAG laser in combination with sodium hypochlorite].

PubMed

Zhou, Meng-Qi; Wang, Hao-Ming; Xiao, Jia-Qi; Hong, Jin

2016-10-01

To histologically evaluate the efficacy of sodium hypochlorite (NaClO) in combination with Er:YAG (erbium-doped yttrium aluminium garnet) laser in dissolving necrotic tissue and cleaning root canals as well as canal isthmuses. After scanned by cone-beam CT (CBCT), 50 well-prepared premolars with root canal isthmuses were selected and randomly assigned into 5 groups. They were subsequently subjected to different regimens as followed: group A-irrigated with 1% NaClO for 1 minute, group B- irradiated by Er:YAG laser at 0.5 W combined with 1% NaClO irrigation for 1 minute, group C- irradiated by Er:YAG laser at 1.0 W combined with 1% NaClO irrigation for 1 minute, group D- irradiated by Er:YAG laser at 2.0 W combined with 1% NaClO irrigation for 1 minute,group E- negative control. After histological preparation and staining, the cross-sections were evaluated for percentage of tissue removal from root canals and isthmuses. The cleanliness values were calculated using SPSS 13.0 software package. The mean percentage of root canals in group A, B, C and D was 95.24%, 96.53%、97.63% and 98.22%, respectively, and the mean percentage of isthmuses was 16.50%, 51.48%, 52.56% and 53.83%, respectively. The mean percentage of root canal and isthmus cleanliness values were significantly higher in group B, C and D (P<0.05) than that in group A. There was no significant differences of root canal and isthmus cleanliness among group B, C and D. Er:YAG laser combined with 1% NaClO irrigation may be used effectively in root canal and root canal isthmus cleanliness as a new method.

Salinity control in a clay soil beneath an orchard irrigated with treated waste water in the presence of a high water table: A numerical study

NASA Astrophysics Data System (ADS)

Russo, David; Laufer, Asher; Bardhan, Gopali; Levy, Guy J.

2015-12-01

A citrus orchard planted on a structured, clay soil associated with a high water table, irrigated by drip irrigation system using treated waste water (TWW) and local well water (LWW) was considered here. The scope of the present study was to analyze transport of mixed-ion, interacting salts in a combined vadose zone-groundwater flow system focusing on the following issues: (i) long-term effects of irrigation with TWW on the response of the flow system, identifying the main factors (e.g., soil salinity, soil sodicity) that control these effects, and (ii) salinity control aiming at improving both crop productivity and groundwater quality. To pursue this two-fold goal, 3-D numerical simulations of field-scale flow and transport were performed for an extended period of time, considering realistic features of the soil, water table, crop, weather and irrigation, and the coupling between the flow and the transport through the dependence of the soil hydraulic functions, K(ψ) and θ(ψ), on soil solution concentration C, and sodium adsorption ratio, SAR. Results of the analyses suggest that in the case studied, the long-term effect of irrigation with TWW on the response of the flow system is attributed to the enhanced salinity of the TWW, and not to the increase in soil sodicity. The latter findings are attributed to: (i) the negative effect of soil salinity on water uptake, and the tradeoff between water uptake and drainage flux, and, concurrently, solute discharge below the root zone; and, (ii) the tradeoff between the effects of C and SAR on K(ψ) and θ(ψ). Furthermore, it was demonstrated that a data-driven protocol for soil salinity control, based on alternating irrigation water quality between TWW and desalinized water, guided by the soil solution salinity at the centroid of the soil volume active in water uptake, may lead to a substantial increase in crop yield, and to a substantial decrease in the salinity load in the groundwater.

Evaluation of triple antibiotic paste removal by different irrigation procedures.

PubMed

Berkhoff, Julie A; Chen, Paul B; Teixeira, Fabricio B; Diogenes, Anibal

2014-08-01

Regenerative endodontics aims to re-establish a functional pulp-dentin complex. First, the root canal system is disinfected primarily by irrigants and medicaments. Triple antibiotic paste (TAP), a commonly used intracanal medicament, has been shown to be directly toxic to stem cells at concentrations greater than 0.1 g/mL. Thus, its complete removal is a crucial step in regenerative endodontic procedures. We hypothesized that currently used irrigation techniques do not completely remove TAP from root canal system. TAP was radiolabeled by the incorporation of I(125), and calcium hydroxide (Ultracal; Ultradent, South Jordan, UT) was radiolabeled with Ca(45). The intracanal medicaments were placed into standardized human root segments and incubated for 28 days at 37°C. Then, canals were irrigated with EndoActivator (Dentsply, Tulsa, OK), passive ultrasonic irrigation, EndoVac (SybronEndo, Coppell, TX), or a syringe/Max-i-Probe needle (Dentsply Rinn, Elgin, IL) using a standardized irrigation protocol in a closed system. Radioactivity levels (counts per minute values) were measured for each tooth before and after the irrigation protocols. Furthermore, the canals were sequentially enlarged and dentin samples collected and evaluated for radioactivity. Data were analyzed with analysis of variance and Bonferroni post hoc testing (P < .05). Approximately 88% of the TAP was retained in the root canal system regardless of the irrigation technique used (no difference among groups). Furthermore, approximately 50% of the radiolabeled TAP was present circumferentially up to 350 μm within the dentin. Conversely, up to 98% of the radiolabeled intracanal calcium hydroxide was removed, and most residual medicament was found present in the initial 50 μm of dentin. Current irrigation techniques do not effectively remove TAP from root canal systems, possibly because of its penetration and binding into dentin. However, calcium hydroxide is effectively removed with significant less residual presence. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Comparison of the Antibacterial Effect and Smear Layer Removal Using Photon-Initiated Photoacoustic Streaming Aided Irrigation Versus a Conventional Irrigation in Single-Rooted Canals: An In Vitro Study

PubMed Central

Zhu, Xiaofei; Yin, Xingzhe; Chang, Jeffrey W.W.; Wang, Yu; Cheung, Gary S.P.

2013-01-01

Abstract Objective: The Er:YAG laser with photon-induced photoacoustic streaming (PIPS) technique was reported to be effective in root canal disinfection. This study attempted to further investigate the antibacterial efficacy and smear layer removal ability of PIPS in comparison with conventional syringe irrigation in vitro. Methods: For antibacterial analysis, 48 single-rooted human teeth were prepared and inoculated with Enterococcus faecalis, and then divided into six groups of eight roots each. The colony-forming units (CFUs) per milliliter were determined after infection as the baseline. Then, the teeth were subjected to either PIPS plus 3% sodium hypochlorite (PIPS+NaOCl) or conventional syringe irrigation with 0.9% saline, 3% NaOCl, 17% ethylenediaminetetraacetic acid (EDTA), 0.2% chlorhexidine gluconate (CHX), or 3% NaOCl alternating with 17% EDTA. The reduction of CFUs in the individual group was determined. Additionally, scanning electron microscopy (SEM) examination of the canal walls for E. faecalis colonization was performed. For comparing the smear removal efficacy, another 48 single-rooted teeth, assigned to different groups as mentioned, were irrigated after mechanical instrumentation. The presence of a smear layer at different levels of the root canal was scored by SEM examination. Results: No significant differences were found in CFU reduction. No bacteria could be observed by SEM in the NaOCl, NaOCl+EDTA, and PIPS+NaOCl groups. The scores of smear layer of the NaOCl+EDTA and PIPS+NaOCl groups were significantly lower than those of the other groups in the coronal and middle third of the root canal. None of the methods can effectively remove smear layer in the apical third. Conclusions: PIPS system supplied with NaOCl and conventional syringe irrigation with NaOCl+EDTA are comparable in their ability to remove E. faecalis and smear layer in single-rooted canals. PMID:23863104

Three-dimensional modeling of nitrate-N transport in vadose zone: Roles of soil heterogeneity and groundwater flux.

PubMed

Akbariyeh, Simin; Bartelt-Hunt, Shannon; Snow, Daniel; Li, Xu; Tang, Zhenghong; Li, Yusong

2018-04-01

Contamination of groundwater from nitrogen fertilizers in agricultural lands is an important environmental and water quality management issue. It is well recognized that in agriculturally intensive areas, fertilizers and pesticides may leach through the vadose zone and eventually reach groundwater. While numerical models are commonly used to simulate fate and transport of agricultural contaminants, few models have considered a controlled field work to investigate the influence of soil heterogeneity and groundwater flow on nitrate-N distribution in both root zone and deep vadose zone. In this work, a numerical model was developed to simulate nitrate-N transport and transformation beneath a center pivot-irrigated corn field on Nebraska Management System Evaluation area over a three-year period. The model was based on a realistic three-dimensional sediment lithology, as well as carefully controlled irrigation and fertilizer application plans. In parallel, a homogeneous soil domain, containing the major sediment type of the site (i.e. sandy loam), was developed to conduct the same water flow and nitrate-N leaching simulations. Simulated nitrate-N concentrations were compared with the monitored nitrate-N concentrations in 10 multi-level sampling wells over a three-year period. Although soil heterogeneity was mainly observed from top soil to 3 m below the surface, heterogeneity controlled the spatial distribution of nitrate-N concentration. Soil heterogeneity, however, has minimal impact on the total mass of nitrate-N in the domain. In the deeper saturated zone, short-term variations of nitrate-N concentration correlated with the groundwater level fluctuations. Copyright © 2018 Elsevier B.V. All rights reserved.

Three-dimensional modeling of nitrate-N transport in vadose zone: Roles of soil heterogeneity and groundwater flux

NASA Astrophysics Data System (ADS)

Akbariyeh, Simin; Bartelt-Hunt, Shannon; Snow, Daniel; Li, Xu; Tang, Zhenghong; Li, Yusong

2018-04-01

Contamination of groundwater from nitrogen fertilizers in agricultural lands is an important environmental and water quality management issue. It is well recognized that in agriculturally intensive areas, fertilizers and pesticides may leach through the vadose zone and eventually reach groundwater. While numerical models are commonly used to simulate fate and transport of agricultural contaminants, few models have considered a controlled field work to investigate the influence of soil heterogeneity and groundwater flow on nitrate-N distribution in both root zone and deep vadose zone. In this work, a numerical model was developed to simulate nitrate-N transport and transformation beneath a center pivot-irrigated corn field on Nebraska Management System Evaluation area over a three-year period. The model was based on a realistic three-dimensional sediment lithology, as well as carefully controlled irrigation and fertilizer application plans. In parallel, a homogeneous soil domain, containing the major sediment type of the site (i.e. sandy loam), was developed to conduct the same water flow and nitrate-N leaching simulations. Simulated nitrate-N concentrations were compared with the monitored nitrate-N concentrations in 10 multi-level sampling wells over a three-year period. Although soil heterogeneity was mainly observed from top soil to 3 m below the surface, heterogeneity controlled the spatial distribution of nitrate-N concentration. Soil heterogeneity, however, has minimal impact on the total mass of nitrate-N in the domain. In the deeper saturated zone, short-term variations of nitrate-N concentration correlated with the groundwater level fluctuations.

Irrigation dynamics associated with positive pressure, apical negative pressure and passive ultrasonic irrigations: a computational fluid dynamics analysis.

PubMed

Chen, José Enrique; Nurbakhsh, Babak; Layton, Gillian; Bussmann, Markus; Kishen, Anil

2014-08-01

Complexities in root canal anatomy and surface adherent biofilm structures remain as challenges in endodontic disinfection. The ability of an irrigant to penetrate into the apical region of a canal, along with its interaction with the root canal walls, will aid in endodontic disinfection. The aim of this study was to qualitatively examine the irrigation dynamics of syringe irrigation with different needle tip designs (open-ended and closed-ended), apical negative pressure irrigation with the EndoVac® system, and passive ultrasonic-assisted irrigation, using a computational fluid dynamics model. Syringe-based irrigation with a side-vented needle showed a higher wall shear stress than the open-ended but was localised to a small region of the canal wall. The apical negative pressure mode of irrigation generated the lowest wall shear stress, while the passive-ultrasonic irrigation group showed the highest wall shear stress along with the greatest magnitude of velocity. © 2013 The Authors. Australian Endodontic Journal © 2013 Australian Society of Endodontology.

The Farm Process Version 2 (FMP2) for MODFLOW-2005 - Modifications and Upgrades to FMP1

USGS Publications Warehouse

Schmid, Wolfgang; Hanson, R.T.

2009-01-01

The ability to dynamically simulate the integrated supply-and-demand components of irrigated agricultural is needed to thoroughly understand the interrelation between surface water and groundwater flow in areas where the water-use by vegetation is an important component of the water budget. To meet this need, the computer program Farm Process (FMP1) was updated and refined for use with the U.S. Geological Survey's MODFLOW-2005 groundwater-flow model, and is referred to as MF2005-FMP2. The updated program allows the simulation, analysis, and management of nearly all components of human and natural water use. MF2005-FMP2 represents a complete hydrologic model that fully links the movement and use of groundwater, surface water, and imported water for water consumption of irrigated agriculture, but also of urban use, and of natural vegetation. Supply and demand components of water use are analyzed under demand-driven and supply-constrained conditions. From large- to small-scale settings, the MF2005-FMP2 has the unique set of capabilities to simulate and analyze historical, present, and future conditions. MF2005-FMP2 facilitates the analysis of agricultural water use where little data is available for pumpage, land use, or agricultural information. The features presented in this new version of FMP2 along with the linkages to the Streamflow Routing (SFR), Multi-Node Well (MNW), and Unsaturated Zone Flow (UZF) Packages prevents mass loss to an open system and helps to account for 'all of the water everywhere and all of the time'. The first version, FMP1 for MODFLOW-2000, is limited to (a) transpiration uptake from unsaturated root zones, (b) on-farm efficiency defined solely by farm and not by crop type, (c) a simulation of water use and returnflows related only to irrigated agriculture and not also to non-irrigated vegetation, (d) a definition of consumptive use as potential crop evapotranspiration, (e) percolation being instantly recharged to the uppermost active aquifer, (f) automatic routing of returnflow from runoff either to reaches of tributary stream segments adjacent to a farm or to one reach nearest to the farm's lowest elevation, (g) farm-well pumping from cell locations regardless of whether an irrigation requirement from these cells exists or not, and (h) specified non-routed water transfers from an undefined source outside the model domain. All of these limitations are overcome in MF2005-FMP2. The new features include (a) simulation of transpiration uptake from variably saturated, fully saturated, or ponded root zones (for example, for crops like rice or riparian vegetation), (b) definition of on-farm efficiency not only by farm but also by crop, (c) simulation of water use and returnflow from non-irrigated vegetation (for example, rain-fed agriculture or native vegetation), (d) use of crop coefficients and reference evapotranspiration, (e) simulation of the delay between percolation from farms through the unsaturated zone and recharge into the uppermost active aquifer by linking FMP2 to the UZF Package, (f) an option to manually control the routing of returnflow from farm runoff to streams, (g) an option to limit pumping to wells located only in cells where an irrigation requirement exists, and (h) simulation of water transfers to farms from a series of well fields (for example, recovery well field of an aquifer-storage-and-recovery system, ASR). In addition to the output of an economic budget for each farm between irrigation demand and supply ('Farm Demand and Supply Budget' in FMP1), a new output option called 'Farm Budget' was created for FMP2, which allows the user to track all physical flows into and out of a water accounting unit at all times. Such a unit can represent individual farms, farming districts, natural areas, or urban areas. The example model demonstrates the application of MF2005-FMP2 with delayed recharge through an unsaturated zone, rejected infiltration in a riparian area, changes in de

Apical extrusion of debris: a literature review of an inherent occurrence during root canal treatment.

PubMed

Tanalp, J; Güngör, T

2014-03-01

Extrusion of intracanal debris as well as irrigants is a common occurrence during root canal treatment, and no instrument or technique has thoroughly solved this problem. Because flare-ups may arise with any irritation directed towards periapical tissues, a shaping or irrigation technique should minimize the risk of apical extrusion, even though it may not be prevented. There has been a rapid evolution of root canal instruments and irrigation systems through the last decade, and many have been assessed for their debris extrusion potential. The purpose of this review was to identify publications regarding the evaluation of debris, bacteria and irrigant extrusion during root canal treatment. A PubMed, Ovid and MEDLINE search was conducted using the keywords "apical extrusion", "debris extrusion" and "endodontic treatment". The literature search extended over a period of more than 30 years up to 2012. Content of the review was limited to apical extrusion of debris and irrigants, extrusion of liquid by irrigation methods and bacterial extrusion. Issues relevant to apical extrusion were obtained by further search in the reference sections of the retrieved articles. The review provides an update on the current status of apical extrusion. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

EnviroAtlas - Agricultural Water Demand by 12-Digit HUC for the Conterminous United States

EPA Pesticide Factsheets

The national agricultural water demand metric provides insight into the amount of water currently used for agricultural irrigation in the contiguous United States. The values are based on 2005 irrigation water use; combined 2010 crop, 2006 land use, and 2001 remotely sensed irrigation location estimates; and have been summarized by watershed or 12-digit hydrologic unit code (HUC). Agricultural irrigation water use, as defined in this case, meets a variety of needs before, during, and after growing seasons (e.g., dust suppression, field preparation, chemical application, weed control, salt removal from root zones, frost protection, crop cooling, and harvesting). Estimates include self-supplied surface and groundwater, as well as supplies from irrigation-specific organizations (e.g., companies, districts, cooperatives, government). This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

Sodium hypochlorite in endodontics: an update review.

PubMed

Mohammadi, Zahed

2008-12-01

The major objective in root canal treatment is to disinfect the entire root canal system. This requires that the pulpal contents be eliminated as sources of infection. This goal may be accomplished using mechanical instrumentation and chemical irrigation, in conjunction with medication of the root canal between treatment sessions. Microorganisms and their by-products are considered to be the major cause of pulpal and periradicular pathosis. In order to reduce or eliminate bacteria and pulpal tissue remnants, various irrigation solutions have been suggested to be used during treatment. Sodium hypochlorite, an excellent non-specific proteolytic and antimicrobial agent, is the most common irrigation solution used during root canal therapy. The purpose of this paper was to review different aspects of sodium hypochlorite use in endodontics.

Additional disinfection with a modified salt solution in a root canal model.

PubMed

van der Waal, Suzette V; Oonk, Charlotte A M; Nieman, Selma H; Wesselink, Paul R; de Soet, Johannes J; Crielaard, Wim

2015-10-01

The aim of this study is to investigate the disinfecting properties of a modified salt solution (MSS) and calcium hydroxide (Ca(OH)2) in a non-direct-contact ex-vivo model. Seventy-four single-canal roots infected with Enterococcus faecalis were treated with 1% sodium hypochlorite (NaOCl) irrigation or with NaOCl irrigation with subsequent dressing with MSS or Ca(OH)2. After removal of the dressings, the roots were filled with bacterial growth medium and incubated for seven days to enable the surviving bacteria to repopulate the root canal lumen. Growth was determined by sampling the root canals with paper points before treatment (S1), after treatment (S2) and incubation after treatment (S3). The colony forming units were counted at S1 and S2. At S3, growth was determined as no/yes regrowth. The Kruskal-Wallis, McNemar and χ(2) test were used for statistical analyses. At S2, in the NaOCl group, growth was found in 5 of 19 root canals. After the removal of MSS or Ca(OH)2 bacteria were retrieved from one root canal in both groups. At S3, repopulation of the root canals had occurred in 14 of 19 roots after sole NaOCl irrigation, 6 of 20 roots after MSS-dressing and in 14 of 20 roots after Ca(OH)2-dressing. MSS was more effective in preventing regrowth than Ca(OH)2 (P=0.009). The modified salt solution prevented regrowth in roots which indicates that it can eliminate persistent bacteria. Dressing the root canals with Ca(OH)2 did not provide additional disinfection after NaOCl irrigation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Wettability of root canal sealers on intraradicular dentine treated with different irrigating solutions.

PubMed

Ballal, Nidambur Vasudev; Tweeny, Adlyn; Khechen, Khaled; Prabhu, K Narayan; Satyanarayan; Tay, Franklin R

2013-06-01

The aim of this in vitro study was to evaluate the wettability of AH Plus and ThermaSeal Plus sealers on intraradicular dentine treated with different irrigating solutions. Fifty anterior teeth were decoronated and split longitudinally. Each root half was divided into 5 groups (n=10). Group I: 5mL of 2.5% NaOCl+QMix. Group II: 5mL of 2.5% NaOCl+17% EDTA. Group III: 5mL of 2.5% NaOCl+7% maleic acid. Group IV: 5mL of 2.5% NaOCl. Group V: 5mL of distilled water. Irrigation regimens were performed for 1min. Each specimen was placed inside a Dynamic Contact Angle Analyser. A controlled-volume droplet of sealer was placed on each specimen and the static contact angle was analysed. The contact angle made by both sealers with EDTA-irrigated dentine was significantly larger when compared to the other irrigants (P<0.05). For ThermaSeal Plus, contact angles produced on maleic acid-, NaOCl- and distilled water-irrigated dentine were not significantly different, but were all significantly larger than the contact angle produced on QMix-irrigated dentine (P<0.05). For AH Plus, contact angles produced on NaOCl- and distilled water-irrigated dentine were not significantly different, but were significantly larger than those made by maleic acid and QMix. When used as a final irrigant, QMix favours the wetting of root canal dentine by both AH Plus and ThermaSeal Plus sealers. Maleic acid shows a promising result when compared to EDTA and NaOCl. Wettability of both sealers is the worst on EDTA-irrigated dentine. The present study highlights the effect of newer endodontic irrigating solutions on the wettability of sealers on to the root canal dentine, which is required for obtaining good obturation seal. Copyright © 2013 Elsevier Ltd. All rights reserved.

An optimization model to design and manage subsurface drip irrigation system for alfalfa

NASA Astrophysics Data System (ADS)

Kandelous, M.; Kamai, T.; Vrugt, J. A.; Simunek, J.; Hanson, B.; Hopmans, J. W.

2010-12-01

Subsurface drip irrigation (SDI) is one of the most efficient and cost-effective methods for watering alfalfa plants. Lateral installation depth and distance, emitter discharge, and irrigation time and frequency of SDI, in addition to soil and climatic conditions affect alfalfa’s root water uptake and yield. Here we use a multi-objective optimization approach to find optimal SDI strategies. Our approach uses the AMALGAM evolutionary search method, in combination with the HYDRUS-2D unsaturated flow model to maximize water uptake by alfalfa’s plant roots, and minimize loss of irrigation and drainage water to the atmosphere or groundwater. We use a variety of different objective functions to analyze SDI. These criteria include the lateral installation depth and distance, the lateral discharge, irrigation duration, and irrigation frequency. Our framework includes explicit recognition of the soil moisture status during the simulation period to make sure that the top soil is dry for harvesting during the growing season. Initial results show a wide spectrum of optimized SDI strategies for different root distributions, soil textures and climate conditions. The developed tool should be useful in helping farmers optimize their irrigation strategy and design.

Measurement and visualization of file-to-wall contact during ultrasonically activated irrigation in simulated canals.

PubMed

Boutsioukis, C; Verhaagen, B; Walmsley, A D; Versluis, M; van der Sluis, L W M

2013-11-01

(i) To quantify in a simulated root canal model the file-to-wall contact during ultrasonic activation of an irrigant and to evaluate the effect of root canal size, file insertion depth, ultrasonic power, root canal level and previous training, (ii) To investigate the effect of file-to-wall contact on file oscillation. File-to-wall contact was measured during ultrasonic activation of the irrigant performed by 15 trained and 15 untrained participants in two metal root canal models. Results were analyzed by two 5-way mixed-design anovas. The level of significance was set at P < 0.05. Additionally, high-speed visualizations, laser-vibrometer measurements and numerical simulations of the file oscillation were conducted. File-to-wall contact occurred in all cases during 20% of the activation time. Contact time was significantly shorter at high power (P < 0.001), when the file was positioned away from working length (P < 0.001), in the larger root canal (P < 0.001) and from coronal towards apical third of the root canal (P < 0.002), in most of the cases studied. Previous training did not show a consistent significant effect. File oscillation was affected by contact during 94% of the activation time. During wall contact, the file bounced back and forth against the wall at audible frequencies (ca. 5 kHz), but still performed the original 30 kHz oscillations. Travelling waves were identified on the file. The file oscillation was not dampened completely due to the contact and hydrodynamic cavitation was detected. Considerable file-to-wall contact occur-red during irrigant activation. Therefore, the term 'Passive Ultrasonic Irrigation' should be amended to 'Ultrasonically Activated Irrigation'. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Long-term tillage and crop rotation effects on residual nitrate in the crop root zone and nitrate accumulation in the intermediate vadose zone

USGS Publications Warehouse

Katupitiya, A.; Eisenhauer, D.E.; Ferguson, R.B.; Spalding, R.F.; Roeth, F.W.; Bobier, M.W.

1997-01-01

Tillage influences the physical and biological environment of soil. Rotation of crops with a legume affects the soil N status. A furrow irrigated site was investigated for long-term tillage and crop rotation effects on leaching of nitrate from the root zone and accumulation in the intermediate vadose zone (IVZ). The investigated tillage systems were disk-plant (DP), ridge-till (RT) and slot-plant (SP). These tillage treatments have been maintained on the Hastings silt loam (Udic Argiustoll) and Crete silt loam (Pachic Argiustoll) soils since 1976. Continuous corn (CC) and corn soybean (CS) rotations were the subtreatments. Since 1984, soybeans have been grown in CS plots in even calendar years. All tillage treatments received the same N rate. The N rate varied annually depending on the root zone residual N. Soybeans were not fertilized with N-fertilizer. Samples for residual nitrate in the root zone were taken in 8 of the 15 year study while the IVZ was only sampled at the end of the study. In seven of eight years, root zone residual soil nitrate-N levels were greater with DP than RT and SP. Residual nitrate-N amounts were similar in RT and SP in all years. Despite high residual nitrate-N with DP and the same N application rate, crop yields were higher in RT and SP except when DP had an extremely high root zone nitrate level. By applying the same N rates on all tillage treatments, DP may have been fertilized in excess of crop need. Higher residual nitrate-N in DP was most likely due to a combination of increased mineralization with tillage and lower yield compared to RT and SP. Because of higher nitrate availability with DP, the potential for nitrate leaching from the root zone was greater with DP as compared to the RT and SP tillage systems. Spring residual nitrate-N contents of DP were larger than RT and SP in both crop rotations. Ridge till and SP systems had greater nitrate-N with CS than CC rotations. Nitrate accumulation in IVZ at the upstream end of the field was twice as high with DP compared to RT and SP. At the downstream end, it was 2.4 and 1.6 times greater with DP than RT and SP, respectively. Nitrate concentration was greater in the IVZ of DP compared to RT and SP tillage systems. Nitrate accumulations in IVZ of RT and SP were not different. Continuous corn had slightly higher nitrate levels in IVZ than CS. The depth of nitrate penetration at the upstream end was greater than that of the downstream end. Estimated rates of nitrate movement ranged from 0.87 to 0.92 m yr-1 at the upstream end and 0.73 to 0.78 m yr-1 at the downstream end.

Quantitative imaging of rhizosphere pH and CO2 dynamics with planar optodes.

PubMed

Blossfeld, Stephan; Schreiber, Christina Maria; Liebsch, Gregor; Kuhn, Arnd Jürgen; Hinsinger, Philippe

2013-07-01

Live imaging methods have become extremely important for the exploration of biological processes. In particular, non-invasive measurement techniques are key to unravelling organism-environment interactions in close-to-natural set-ups, e.g. in the highly heterogeneous and difficult-to-probe environment of plant roots: the rhizosphere. pH and CO2 concentration are the main drivers of rhizosphere processes. Being able to monitor these parameters at high spatio-temporal resolution is of utmost importance for relevant interpretation of the underlying processes, especially in the complex environment of non-sterile plant-soil systems. This study introduces the application of easy-to-use planar optode systems in different set-ups to quantify plant root-soil interactions. pH- and recently developed CO2-sensors were applied to rhizobox systems to investigate roots with different functional traits, highlighting the potential of these tools. Continuous and highly resolved real-time measurements were made of the pH dynamics around Triticum turgidum durum (durum wheat) roots, Cicer arietinum (chickpea) roots and nodules, and CO2 dynamics in the rhizosphere of Viminaria juncea. Wheat root tips acidified slightly, while their root hair zone alkalized their rhizosphere by more than 1 pH unit and the effect of irrigation on soil pH could be visualized as well. Chickpea roots and nodules acidified the surrounding soil during N2 fixation and showed diurnal changes in acidification activity. A growing root of V. juncea exhibited a large zone of influence (mm) on soil CO2 content and therefore on its biogeochemical surrounding, all contributing to the extreme complexity of the root-soil interactions. This technique provides a unique tool for future root research applications and overcomes limitations of previous systems by creating quantitative maps without, for example, interpolation and time delays between single data points.

Monitoring the Impact of Climate Change on Soil Salinity in Agricultural Areas Using Ground and Satellite Sensors

NASA Astrophysics Data System (ADS)

Corwin, D. L.; Scudiero, E.

2017-12-01

Changes in climatic patterns have had dramatic influence on agricultural areas worldwide, particularly in irrigated arid-zone agricultural areas subjected to recurring drought, such as California's San Joaquin Valley (SJV), or areas receiving above average rainfall for a decade or more, such as Minnesota's Red River Valley (RRV). Climate change has impacted water availability with an under or over abundance, which subsequently has impacted soil salinity levels in the root zone primarily from the upward movement of salts from shallow water tables. Inventorying and monitoring the impact of climate change on soil salinity is crucial to evaluate the extent of the problem, to recognize trends, and to formulate state-wide and field-scale irrigation, drainage, and crop management strategies that will sustain the agricultural productivity of the SJV and RRV. Over the past 3 decades, Corwin and colleagues at the U.S. Salinity Laboratory have developed proximal sensor (i.e., electrical resistivity and electromagnetic induction) and remote imagery (i.e., MODIS and Landsat 7) methodologies for assessing soil salinity at multiple scales: field (0.5 ha to 3 km2), landscape (3 to 10 km2), and regional (10 to 105 km2) scales. The purpose of this presentation is to provide an overview of these scale-dependent salinity assessment technologies. Case studies for SJV and RRV are presented to demonstrate at multiple scales the utility of these approaches in assessing soil salinity changes due to management-induced changes and to changes in climate patterns, and in providing site-specific irrigation management information for salinity control. Decision makers in state and federal agencies, irrigation and drainage district managers, soil and water resource managers, producers, agriculture consultants, extension specialists, and Natural Resource Conservation Service field staff are the beneficiaries of this information.

Partitioning Evapotranspiration into Green and Blue Water Sources in the Conterminous United States.

PubMed

Velpuri, Naga Manohar; Senay, Gabriel B

2017-07-21

In this study, we combined two 1 km actual evapotranspiration datasets (ET), one obtained from a root zone water balance model and another from an energy balance model, to partition annual ET into green (rainfall-based) and blue (surface water/groundwater) sources. Time series maps of green water ET (GWET) and blue water ET (BWET) are produced for the conterminous United States (CONUS) over 2001-2015. Our results indicate that average green and blue water for all land cover types in CONUS accounts for nearly 70% and 30% of the total ET, respectively. The ET in the eastern US arises mostly from GWET, and in the western US, it is mostly BWET. Analysis of the BWET in the 16 irrigated areas in CONUS revealed interesting results. While the magnitude of the BWET gradually showed a decline from west to east, the increase in coefficient of variation from west to east confirmed greater use of supplemental irrigation in the central and eastern US. We also established relationships between different hydro-climatology zones and their blue water requirements. This study provides insights on the relative contributions and the spatiotemporal dynamics of GWET and BWET, which could lead to improved water resources management.

Antibacterial Efficacy of Calcium Hypochlorite with Vibringe Sonic Irrigation System on Enterococcus faecalis: An In Vitro Study

PubMed Central

Dumani, Aysin; Guvenmez, Hatice Korkmaz; Yilmaz, Sehnaz; Yoldas, Oguz; Kurklu, Zeliha Gonca Bek

2016-01-01

Aim. The purpose of this study was to compare the in vitro efficacy of calcium hypochlorite (Ca[OCl]2) and sodium hypochlorite (NaOCl) associated with sonic (Vibringe) irrigation system in root canals which were contaminated with Enterococcus faecalis. Material and Methods. The root canals of 84 single-rooted premolars were enlarged up to a file 40, autoclaved, inoculated with Enterococcus faecalis, and incubated for 21 days. The samples were divided into 7 groups according to the irrigation protocol: G0: no treatment; G1: distilled water; G2: 2.5% NaOCl; G3: 2.5% Ca(OCl)2; G4: distilled water with sonic activation; G5: 2.5% NaOCl with sonic activation; and G6: 2.5% Ca(OCl)2 with sonic activation. Before and after decontamination procedures microbiological samples were collected and the colony-forming units were counted and the percentages of reduction were calculated. Results. Distilled water with syringe irrigation and sonic activation groups demonstrated poor antibacterial effect on Enterococcus faecalis compared to other experimental groups (p < 0.05). There was no statistically significant difference between syringe and sonic irrigation systems with Ca(OCl)2 and NaOCl. Conclusion. The antimicrobial property of Ca(OCl)2 has been investigated and compared with that of NaOCl. Both conventional syringe irrigation and sonic irrigation were found effective at removing E. faecalis from the root canal of extracted human teeth. PMID:27218106

Effect of ultrasonic activation on the reduction of bacteria and endotoxins in root canals: a randomized clinical trial.

PubMed

Nakamura, V C; Pinheiro, E T; Prado, L C; Silveira, A C; Carvalho, A P L; Mayer, M P A; Gavini, G

2018-01-01

This randomized clinical trial aimed to compare the effectiveness of ultrasonic activation with that of nonactivated irrigation on the removal of bacteria and endotoxin from root canals. Fifty patients with necrotic pulps and asymptomatic apical periodontitis were randomly allocated into two groups according to the final irrigation protocol after root canal preparation: Group UI - ultrasonic irrigation (n = 25) and Group NI - needle irrigation (n = 25). The root canals were medicated with calcium hydroxide for 14 days. Microbiological sampling was performed before (S1) and after the root canal preparation (S2), after the irrigation protocols (S3) and after the removal of the intracanal medication (S4). Total bacteria counts were determined by qPCR and the endotoxin levels by the limulus amebocyte lysate assay. Intragroup analyses were performed using the Wilcoxon test for related samples, whereas intergroup analyses were performed using the Mann-Whitney U-test (P < 0.05). All S1 samples were positive for bacteria, with median numbers of 1.49 × 10 6 and 8.55 × 10 5 bacterial cells for the UI and NI groups, respectively. This number significantly decreased in S2 samples (UI: 1.41 × 10 4 ; NI: 3.53 × 10 4 ; both with P < 0.001). After final irrigation protocols, there was a significant decrease in bacterial load from S2 to S3 samples in both groups (UI: 4.29 × 10 3 ; NI: 1.08 × 10 4 ; P < 0.01). Intergroup analysis revealed a significant difference between irrigation methods regarding bacterial counts in S3 samples (P < 0.05). In contrast, no significant differences were observed between groups for endotoxin levels (P > 0.05). Ultrasonic activation was more effective than nonactivated irrigation for reducing the number of bacteria but not the endotoxin levels in root canals of teeth with apical periodontitis. © 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.

A novel experimental approach to investigate the effect of different agitation methods using sodium hypochlorite as an irrigant on the rate of bacterial biofilm removal from the wall of a simulated root canal model.

PubMed

Mohmmed, Saif Alarab; Vianna, Morgana E; Penny, Matthew R; Hilton, Stephen T; Mordan, Nicola; Knowles, Jonathan C

2016-10-01

Root canal irrigation is an important adjunct to control microbial infection. This study aimed primarily to develop a transparent root canal model to study in situ Enterococcus faecalis biofilm removal rate and remaining attached biofilm using passive or active irrigation solution for 90s. The change in available chlorine and pH of the outflow irrigant were assessed. A total of forty root canal models (n=10 per group) were manufactured using 3D printing. Each model consisted of two longitudinal halves of an 18mm length simulated root canal with size 30 and taper 0.06. E. faecalis biofilms were grown on the apical 3mm of the models for 10days in Brain Heart Infusion broth. Biofilms were stained using crystal violet for visualization. The model halves were reassembled, attached to an apparatus and observed under a fluorescence microscope. Following 60s of 9mL of 2.5% NaOCl irrigation using syringe and needle, the irrigant was either left stagnant in the canal or activated using gutta-percha, sonic and ultrasonic methods for 30s. Images were then captured every second using an external camera. The residual biofilm percentages were measured using image analysis software. The data were analyzed using Kruskal-Wallis test and generalized linear mixed model. The highest level of biofilm removal was with ultrasonic agitation (90.13%) followed by sonic (88.72%), gutta-percha (80.59%), and passive irrigation group (control) (43.67%) respectively. All agitation groups reduced the available chlorine and pH of NaOCl more than that in the passive irrigation group. The 3D printing method provided a novel model to create a root canal simulation for studying and understanding a real-time biofilm removal under microscopy. Ultrasonic agitation of NaOCl left the least amount of residual biofilm in comparison to sonic and gutta-percha agitation methods. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Observation and Modelling of Soil Water Content Towards Improved Performance Indicators of Large Irrigation Schemes

NASA Astrophysics Data System (ADS)

Labbassi, Kamal; Akdim, Nadia; Alfieri, Silvia Maria; Menenti, Massimo

2014-05-01

Irrigation performance may be evaluated for different objectives such as equity, adequacy, or effectiveness. We are using two performance indicators: IP2 measures the consistency of the allocation of the irrigation water with gross Crop Water requirements, while IP3 measures the effectiveness of irrigation by evaluating the increase in crop transpiration between the case of no irrigation and the case of different levels of irrigation. To evaluate IP3 we need to calculate the soil water balance for the two cases. We have developed a system based on the hydrological model SWAP (Soil Water atmosphere Plant) to calculate spatial and temporal patterns of crop transpiration T(x, y, t) and of the vertical distribution of soil water content θ(x, y, z, t). On one hand, in the absence of ground measurement of soil water content to validate and evaluate the precision of the estimated one, a possibility would be to use satellite retrievals of top soil water content, such as the data to be provided by SMAP. On the other hand, to calculate IP3 we need root zone rather than top soil water content. In principle, we could use the model SWAP to establish a relationship between the top soil and root zone water content. Such relationship could be a simple empirical one or a data assimilation procedure. In our study area (Doukkala- Morocco) we have assessed the consistency of the water allocation with the actual irrigated area and crop water requirements (CWR) by using a combination of multispectral satellite image time series (i,e RapidEye (REIS), SPOT4 (HRVIR1) and Landsat 8 (OLI) images acquired during the 2012/2013 agricultural season). To obtain IP2 (x, y, t) we need to determine ETc (x, y, t). We have applied two (semi)empirical approaches: the first one is the Kc-NDVI method, based on the correlation between the Near Difference Vegetation Index (NDVI) and the value of crop coefficient (kc); the second one is the analytical approach based on the direct application of Penman-Monteith equation with reflectance-based estimates of canopy biophysical variables, such as surface albedo (r), leaf area index (LAI) and crop height (hc). The validation of spatial results using the dual crop coefficient approach (kcb) showed that the satellite-based estimates of ETc corresponded well with ground-based ETc i.e, R²=0.75 and RMSE=0.79 versus R²=0.73 and RMSE=0.89 for respectively kc-NDVI and analytical approach. To monitor IP3 (x, y, t) with the SWAP model we mapped soil hydrological properties combining soil maps with grain size analysis of a number of samples, and agricultural crops using multi-temporal classification of NDVI time series. The assessment of irrigation performance in term of adequacy between requirement and allocation showed that CWR are much larger than water supply for entire area, this mismatch is improved in the beginning of the growing season by means of Irrigation water requirement (IWR) and even more using the net irrigation water requirement (NIWR) estimated using SWAP model. We expect that the availability of SMAP data products will significantly improve the reliability and temporal sampling of our indicators.

Vegetative and Atmospheric Controls on the Bouchet-Morton Complementary Relationship Hypothesis

NASA Astrophysics Data System (ADS)

Pettijohn, J. C.; Salvucci, G. D.; Phillips, N. G.; Daley, M. J.

2006-12-01

The Bouchet-Morton Complementary Relationship (CR) hypothesis is a potentially-powerful analytic tool to help understand the feedback between evapotranspiring land surfaces and the atmospheric boundary layer (ABL), and how potential evaporation reflects this coupling on multiple time and length scales. In spite of advances in our ability to measure and model these processes, the heuristic CR hypothesis remains an unsolved, first-order problem. The leading theoretical models, i.e., Morton, Granger, and Szilagyi, of the coupled land surface atmosphere mechanisms responsible for CR focus primarily on vertical humidity (vapor pressure) profiles while assuming that vegetative and/or atmospheric diffusivities play an insignificant role in regulating CR. Further, whereas Granger and Szilagyi assume almost opposite vertical temperature profile boundary conditions, both derivations appear to validate CR. Contrary to these multiple working hypotheses' assumptions, our recent CR evaluation of 147 days (1987-1989) at the FIFE temperate grassland discovered that canopy conductance was an essential forcing variable in complementarity, and thus improved CR in application when included in the definition of potential evaporation. To isolate the exact forcing mechanisms of canopy and ABL conductances to complementarity, we evaluated CR in a mixed-deciduous forest at Harvard Forest (summers 2005-2006) by comparing daily averaged water-stressed (non-irrigated, regionally stressed soil moisture) and water-unstressed (irrigated, `potential') transpiration. Root-zone soil moisture of a red maple (Acer rubrum L.) sample set was elevated using a pulse-irrigation system. Whole-tree transpiration of the `potential` (water-unstressed) and a reference (water-stressed) set of maples was monitored at high frequency using heat-dissipation Granier-type sap flux sensors. To isolate physiological and/or atmospheric forcing of CR, we estimated isothermal Penman-Monteith transpiration models of both irrigated and non-irrigated time series using a Jarvis type multiplicative stress model of scaled canopy conductance to water vapor transport. Poorly-constrained model parameters (e.g., environmental stress boundary conditions) were estimated using a grid search routine; further, parameter confidence limits were inferred using bootstrap replacement sampling. Preliminary results suggest the following: (1) the absence of an unstressed canopy conductance in the Penman equation results in violation of fundamental CR assumptions (similar to FIFE); and (2) unlimited root-zone water availability does not reduce the leaf-level stomatal resistance enough to yield complementarity, i.e., the typical CR potential signal is also a function of other environmental stresses, e.g., vapor pressure deficit. In summary, our results yield valuable insight into the role of vertical atmospheric and vegetative conductances in CR.

Multiple-scale Proximal Sensor and Remote Imagery Technology for Sustaining Agricultural Productivity During Climate Change

NASA Astrophysics Data System (ADS)

Corwin, D. L.; Scudiero, E.

2016-12-01

Changes in climatic patterns have had dramatic influence on agricultural areas worldwide, particularly in irrigated arid-zone agricultural areas subjected to recurring drought, such as California's San Joaquin Valley. Climate change has impacted water availability, which subsequently has impacted soil salinity levels in the root zone, especially on the west side of the San Joaquin Valley (WSJV). Inventorying and monitoring the extent of climate change on soil salinity is crucial to evaluate the extent of the problem, to recognize trends, and to formulate state-wide and field-scale irrigation management strategies that will sustain the agricultural productivity of the WSJV. Over the past 3 decades, Corwin and colleagues at the U.S. Salinity Laboratory have developed proximal sensor (i.e., electrical resistivity and electromagnetic induction) and remote imagery (i.e., MODIS and Landsat 7) methodologies for assessing soil salinity at multiple scales: field (0.5 ha to 3 km2), landscape (3 to 10 km2), and regional (10 to 105 km2) scales. The purpose of this presentation is to provide an overview of these scale-dependent salinity assessment technologies. Case studies for the WSJV are presented to demonstrate at multiple scales the utility of these approaches in assessing soil salinity changes due to management-induced changes and to changes in climate patterns, and in providing site-specific irrigation management information for salinity control. Land resource managers, producers, agriculture consultants, extension specialists, and Natural Resource Conservation Service field staff are the beneficiaries of this information.

The antimicrobial effectiveness of 25% propolis extract in root canal irrigation of primary teeth.

PubMed

Verma, Manjesh Kumar; Pandey, Ramesh Kumar; Khanna, Richa; Agarwal, Jyotsna

2014-01-01

The choice of irrigating solution used in root canals of primary teeth is complicated by their complex morphology and paucity of associated literature. Propolis is a natural product that has gained interest in this context due to its antibacterial effectiveness against several endodontic pathogens. The present study was undertaken to assess the potential of water-soluble 25% propolis extract against microorganisms present in root canals of primary teeth during endodontic procedures. The child patients in the age group of 4-7 years with radiographic evidence of carious pulp exposure were included in the study. Definitive selection was done after gaining access into the pulp chamber and root canals of the selected teeth. The clinical and radiographic evidence of pathosis was ruled out for inclusion in the study. The selected teeth were divided into two groups randomly. In Group A 0.9% isotonic saline and in Group B 25% extract water-soluble propolis were used as irrigating solution, respectively. The bacterial samples were collected both pre- and post-irrigation and were transferred for microbial assay. STAISTISTICAL ANALYSIS: Wilcoxon matched signed rank test was used to compare the pre-and post-irrigation bacterial counts. Mann-Whitney test was used to compare the mean change (pre-post) in bacterial colony counts of groups in the study. Antimicrobial effectiveness of 25% water-soluble extract of propolis in the root canals of primary teeth was confirmed in the present study. The reduction in the mean bacterial colony counts of all the isolated bacteria was noticed higher in Group B than Group A. The results of the present study have confirmed that the antibacterial effectiveness of water-soluble extract of propolis in the root canals of primary teeth in vivo. Considering the low toxicity concerns and antibacterial effectiveness, water-soluble extract of 25% propolis can be advocated as a root canal irrigant in endodontic treatment of primary teeth.

Comparison of the Antimicrobial Efficacy of Octenidine Dihydrochloride and Chlorhexidine with and Without Passive Ultrasonic Irrigation - An Invitro Study

PubMed Central

Cherian, Bastin; Manjunath, Mysore Krishnaswamy

2016-01-01

Introduction Elimination of microorganisms from infected root canals is a complicated task. Numerous measures have been described to reduce the microbial load in the root canal system, including the use of various instrumentation techniques, irrigation regimens and intracanal medicaments. The drawbacks of few commonly used irrigants include toxic and harmful side effects, microbial resistance to antimicrobial agents and staining. Hence there is a need for alternative agents which are nontoxic, effective and safe. Aim To compare and evaluate antimicrobial effects of 2% Chlorhexidine (CHX) versus 0.1% Octenidine Dihydrochloride (OCT) as root canal irrigant with and without passive ultrasonic irrigation against Enterococcus faecalis (E. faecalis) in vitro and to evaluate the depth of penetration of irrigant solution into the dentinal tubules at the junction of middle and apical third. Materials and Methods Forty eight freshly extracted, single rooted human mandibular premolars were decoronated and root specimen standardized to 14mm. Biofilm of E. faecalis (strain ATCC 29212) was grown for seven days and the specimens were divided into four groups (n=12) based on irrigation protocol : Group I- Conventional Syringe Irrigation (CSI) with 2% CHX, Group II- CSI + 0.1% OCT, Group III-Passive Ultrasonic Irrigation (PUI) + 2% CHX and Group IV- PUI+ 0.1% OCT. Dentin shavings were collected at two depths (200μm and 400μm) and total number of colony forming units were determined. The data were statistically analyzed using ANOVA, Scheffes multiple comparison of means and paired t-test (p<0.05). Results Group III and IV (PUI) showed significant difference compared to Group I and II (CSI) both at 200μm and 400μm (p=0.000). For Group III and Group IV no significant differences were found at 200μm and 400μm (p=1.000 and 0.363 respectively), however significant difference was found between data at 200μm and 400μm for all the four groups (p=0.000). Conclusion Octenidine (0.1%) was more effective than 2% Chlorhexidine against E. faecalis both at 200μm and 400μm. Passive ultrasonic irrigation proved to enhance the antimicrobial action of the irrigants. PMID:27504415

Water Use Efficiency under Different Tillage and Irrigation Systems for Tomato Farming in Southeastern Brazil

NASA Astrophysics Data System (ADS)

Bhering, S. B.; Fernandes, N. F.; Macedo, J. R.

2009-04-01

In the northwest part of Rio de Janeiro state water availability is one of the main limiting factors for human development and crop productivity. In the same way that shortage of freshwater is one of the main problems, the tomato production systems waste water and highly degrade the environment. The search for the water use efficiency is a challenge in tomato sustainable development production systems. This study aimed to contribute towards the development of sustainable production systems for the tomato farming in the northwestern part or Rio de Janeiro state, as well as increase water use efficiency and the improvement of our understanding on the role played by soil and water management practices on soil hydrology, especially on the amount of water available for the plants. The study was carried out at an experimental watershed in the city of São José do Ubá, in the northwestern portion of Rio de Janeiro state. This city has one of the worst human development index (HDI = 0718) of the state, occupying one of the last 6 positions (85 in 91), with serious problems of education, sanitation, water supply and public health. This area is characterized by an extensive steep hilly topography constituted by long convex-concave hillslopes separated by flat valley-bottoms. The original Atlantic Forest was continuously removed for the introduction of farming and grazing activities, which currently dominate the landscape of the region. The combination of such topographic and land-use characteristics tend to generate a variety of erosional processes, including rill and interrill erosion, gullies and even landslides. The average annual rainfall in the area is about 1,171 mm, with most of rain concentrated during the summer season, making December the wetter and July the drier months. The water balance is negative for most of the year, with the exception of the period from November to January. The cultivation in the area is traditionally done using production systems that highly degrade the environment, applied without practices of soil and water conservation. Such production systems are associated with a variety of environmental problems, such as soil erosion, the extensive pumping of groundwater, the partial obstruction of surface drainage to form artificial lakes, the contamination of groundwater, among others. The environmental impacts generated by all these problems assume a greater importance due to the complete absence of monitoring the continuous lowering of the water table and the changes in water quality. We consider that the main management strategies for developing sustainable production systems for the tomato farming in this area should be based on monitoring water use efficiency, increasing water availability in the root zone and also preventing runoff, leaching and evaporation of water from the soil. Therefore, techniques were applied as green manures with legumes without incorporation of the biomass, non-mechanized and curve-level soil preparation, planting in level, soil cover with crop residues, fertirrigation with solid fertilization of low value, the conduct of tomato especially supported by plastic string attached to a trellis, drip irrigation, and monitoring soil water potential (SWP) with Watermak sensors. At the end of the tomato cycle, water use efficiency and the productivity were compared at 8 micro-plots installed in the 3 studied production systems: conventional tillage (CT-H), minimum tillage (MT-H), both with "wetting irrigation with garden hose", and no-tillage with drip irrigation (NT-D). For each production system, soil physical properties were characterized and soil water potential (SWP) and soil temperature were continuously monitored at different depths (20, 40, 60 and 80 cm), as well as the total water volume used in each irrigation. In parallel, we also compared the development of the root system and the final productivity for each one of the three production systems. The results obtained in this study did no suggest significant modifications on soil physical properties among the three systems. The no-tillage system (NT-D) presented the lower values for average soil temperature and amplitude and supplied more water to the plants, favoring groundwater recharge on the long-term, while preventing runoff, leaching or evaporation of water from the soil. On the other hand, conventional (CT-H) and minimum tillage (MT-H) systems generated water stress conditions, especially during fruiting, maturation and harvest periods. Besides, 75% of the root system is concentrated on the first 30cm of the soil profile while in the no-tillage system with drip irrigation (NT-D) is observed an increase of water availability in the effective root zone (60 cm). The results obtained here also suggest a 50% increase in the production of tomato for the no-tillage system with drip irrigation (NT-D) when compared to the conventional system. Therefore, the results attest that the implementation of simple soil and water conservation practices play an important role toward an improvement of the environmental sustainability of the tomato farming in this area.

Antibacterial Potential of 2.5% Sodium Hypochlorite in Distinct Irrigation Protocols on Enterococcus faecalis Biofilm.

PubMed

Alves, Denise Ramos Silveira; Cunha, Rodrigo Sanches; da Silveira Bueno, Carlos Eduardo; de Alencar, Ana Helena Gonçalves; de Araújo Estrela, Cyntia Rodrigues; dos Santos, Tatiane Oliveira; Estrela, Carlos

2015-05-01

The aim of this study was to evaluate the effect of irrigation methods on antibacterial potential of 2.5% NaOCl on Enterococcus faecalis biofilm. Enterococcus faecalis biofilms were prepared during 60 days on 48 human root canals and randomized into control and experimental groups using positive and negative pressure irrigation. Bacterial growth was analyzed using turbidity of culture medium followed by UV spectrophotometry, and scanning electron microscopy (SEM) analyses were performed. Mean and standard deviations were used for evaluate the mean optical densities associated to the number of bacteria present culture, and Scheirer-Ray-Hare (an extension of the Kruskal-Wallis test) and Tamhane test to analyze the SEM images in the groups and thirds. Significance was set at 5%. Enterococcus faecalis was still present after root canal cleaning regardless of irrigation methods or bacterial identification methods. Positive and negative pressure irrigation protocols using 2.5% NaOCl show a similar capacity to reduce E. faecalis in infected root canals.

Cleaning capacity of octenidine as root canal irrigant: A scanning electron microscopy study.

PubMed

Coaguila-Llerena, Hernán; Stefanini da Silva, Virgínia; Tanomaru-Filho, Mario; Guerreiro Tanomaru, Juliane Maria; Faria, Gisele

2018-06-01

The aim of this study was to assess the cleaning capacity of the octenidine hydrochloride (OCT) used as root canal irrigant by scanning electron microscopy (SEM) analysis. Sixty human unirradicular extracted teeth were randomly distributed in 6 groups (n = 10) according to irrigant solutions which were used during root canal preparation: G1, 0.1% OCT; G2, 2% chlorhexidine (CHX); G3, 2.5% sodium hypochlorite (NaOCl); G4, OCT + 17% ethylenediaminetetraacetic acid (EDTA); G5, 2.5% NaOCl + 17% EDTA and G6, distilled water. All specimens were instrumented with ProTaper system up to F4. Teeth were sectioned and prepared for SEM. The smear layer was evaluated using a 5-score system and the data were analyzed by Kruskal-Wallis and Dunn (α = 0.05). In all root canal thirds there was no significant difference between OCT, CHX, NaOCl, and water groups (p > .05), and these groups showed higher smear layer values than NaOCl + EDTA and OCT + EDTA groups (p < .05). There was no significant difference between NaOCl + EDTA and OCT + EDTA groups (p > .05). It was concluded that OCT used as a single root canal irrigant presented poor cleaning capacity and could be used in association with a final irrigation with EDTA to obtain smear layer removal. © 2018 Wiley Periodicals, Inc.

Comparison of efficacy of pulverization and sterile paper point techniques for sampling root canals.

PubMed

Tran, Kenny T; Torabinejad, Mahmoud; Shabahang, Shahrokh; Retamozo, Bonnie; Aprecio, Raydolfo M; Chen, Jung-Wei

2013-08-01

The purpose of this study was to compare the efficacy of the pulverization and sterile paper point techniques for sampling root canals using 5.25% NaOCl/17% EDTA and 1.3% NaOCl/MTAD (Dentsply, Tulsa, OK) as irrigation regimens. Single-canal extracted human teeth were decoronated and infected with Enterococcus faecalis. Roots were randomly assigned to 2 irrigation regimens: group A with 5.25% NaOCl/17% EDTA (n = 30) and group B with 1.3% NaOCl/MTAD (n = 30). After chemomechanical debridement, bacterial samplings were taken using sterile paper points and pulverized powder of the apical 5 mm root ends. The sterile paper point technique did not show growth in any samples. The pulverization technique showed growth in 24 of the 60 samples. The Fisher exact test showed significant differences between sampling techniques (P < .001). The sterile paper point technique showed no difference between irrigation regimens. However, 17 of the 30 roots in group A and 7 of the 30 roots in group B resulted in growth as detected by pulverization technique. Data showed a significant difference between irrigation regimens (P = .03) in pulverization technique. The pulverization technique was more efficacious in detecting viable bacteria. Furthermore, this technique showed that 1.3% NaOCl/MTAD regimen was more effective in disinfecting root canals. Published by Elsevier Inc.

A New Weak Chelator in Endodontics: Effects of Different Irrigation Regimens with Etidronate on Root Dentin Microhardness

PubMed Central

Tartari, Talita; de Almeida Rodrigues Silva e Souza, Patrícia; Vila Nova de Almeida, Bruno; Carrera Silva Júnior, José Otávio; Facíola Pessoa, Oscar; Silva e Souza Junior, Mario Honorato

2013-01-01

This study investigated the effect of sodium hypochlorite (NaOCl), ethylenediaminetetraacetic (EDTA), etidronic (HEBP), and citric acid (CA) associated in different irrigation regimens on root dentin microhardness. Forty-five root halves of single-rooted teeth were sectioned into thirds that were embedded in acrylic resin, polished, randomly assigned into 3 groups, and treated as follows: G1: saline solution; G2: 5% NaOCl + 18% HEBP, mixed in equal parts; and G3: 2.5% NaOCl. After measurements, the G3 samples were distributed into subgroups G4, G5, and G6, which were submitted to 17% EDTA, 10% CA and 9% HEBP, respectively. Following the new measurements, these groups received a final flush with 2.5% NaOCl, producing G7, G8, and G9. Microhardness was measured with Knoop indenter under a 25 g load for 15 seconds, before and after treatments. The data were statistically analyzed using paired Student's t-test (α<0.05) to compare values before and after treatments and analysis of variance (ANOVA) (α<0.05) to detect any differences among thirds. Except G1, all tested irrigation regimens significantly decreased the microhardness. There were no differences between root thirds before treatments, and all root thirds exhibited equal responses to same treatment. Except saline, all tested irrigation regimens reduced the root dentin microhardness. PMID:23983692

Effect of photodynamic therapy (PDT) on Enterococcus faecalis biofilm in experimental primary and secondary endodontic infections.

PubMed

Tennert, Christian; Feldmann, Katharina; Haamann, Edwina; Al-Ahmad, Ali; Follo, Marie; Wrbas, Karl-Thomas; Hellwig, Elmar; Altenburger, Markus J

2014-11-04

To determine the antibacterial effect of photodynamic Therapy on Enterococcus faecalis (E. faecalis) biofilms in experimentally infected human root canals in primary infections and endodontic retreatments. One hundred and sixty single-rooted extracted teeth with one root canal were prepared using ProTaper instruments. Seventy specimens were left without root canal filling and autoclaved. The root canals of another 70 specimens were filled with Thermafil and AH Plus and the root canal fillings were removed after 24 hours using ProTaper D files and plasma sterilized. The specimens were infected with a clinical isolate of E. faecalis for 72 hours. Samples were taken using sterile paper points to determine the presence of E. faecalis in the root canals. The specimens were randomly divided into groups according to their treatment with 20 teeth each and a control. In the PDT group the teeth were treated using PDT, consisting of the photosensitizer toluidine blue and the PDT light source at 635 nm. In the NaOCl (sodium hypochlorite) group the root canals were rinsed with 10 mL of 3% NaOCl. In the NaOCl-PDT group the root canals were rinsed with 10 mL of 3% of sodium hypochlorite and then treated with PDT. Samples were taken after treatments using sterile paper points. Additionally, remaining root canal filling material was recovered from the root canal walls. Survival fractions of the samples were calculated by counting colony-forming units. A one-way analysis of variance (ANOVA) was applied to the data to assess the effect of different treatment techniques. Antimicrobial treatment of root canals caused a significant reduction of bacterial load in all groups. NaOCl irrigation eliminated E. faecalis most effectively. PDT alone was less effective compared to NaOCl irrigation and the combination of NaOCl irrigation and PDT. CFU levels recovered from the filling material after NaOCl irrigation of the root canals were 10fold higher compared to PDT and the combination of NaOCl irrigation and PDT. Photodynamic therapy killed E. faecalis in experimental primary endodontic infections and retreated human root canals. PDT is an effective supplement in root canal disinfection, especially in endodontic retreatments.

Antimicrobial activity of root canal irrigants against biofilm forming pathogens- An in vitro study

PubMed Central

Ghivari, Sheetal Basavraj; Bhattacharya, Haimanti; Bhat, Kishore G.; Pujar, Madhu A.

2017-01-01

Aims: The aim of the study was to check the antimicrobial activity of the 5% Sodium hypochlorite, 2% Chlorhexidine, 0.10% Octenidine (OCT), and 2% Silver Zeolite (SZ) at different time intervals against a single species biofilm of Enterococcus faecalis, Staphylococcus aureus, and Candida albicans model prepared on a nitrocellulose membrane. Settings and Design: In vitro nitrocellulose biofilm model was used to check antibacterial efficacy of root canal irrigants. Materials and Methods: The in vitro nitrocellulose biofilm model was used to check the antibacterial activity of root canal irrigants. Single species biofilms were suspended into 96-well microtiter plate and treated with root canal irrigants for 1, 5, 10, 15, 30, and 60 s, respectively. The remaining microbial load in the form of colony-forming unit/ml after antimicrobial treatment was tabulated and data were statistically analyzed. Statistical Analysis: SPSS version 17, Kruskal–Wallis ANOVA, Mann–Whitney U-test, and Wilcoxon matched pair test (P < 0.05) were used. Results: All tested microorganisms were eliminated within 30 s by all the antimicrobial substances tested except normal saline. 2% chlorhexidine and 0.10% OCT were equally effective against C. albicans at 30 s. Conclusion: The newly tested irrigants have shown considerable antibacterial activity against selected single species biofilm. OCT (0.10%) can be used as an alternative endodontic irrigant. PMID:29279615

Zone edge effects with variable rate irrigation

USDA-ARS?s Scientific Manuscript database

Variable rate irrigation (VRI) systems may offer solutions to enhance water use efficiency by addressing variability within a field. However, the design of VRI systems should be considered to maximize application uniformity within sprinkler zones, while minimizing edge effects between such zones alo...

A higher sink competitiveness of the rooting zone and invertases are involved in dark stimulation of adventitious root formation in Petunia hybrida cuttings.

PubMed

Klopotek, Yvonne; Franken, Philipp; Klaering, Hans-Peter; Fischer, Kerstin; Hause, Bettina; Hajirezaei, Mohammad-Reza; Druege, Uwe

2016-02-01

The contribution of carbon assimilation and allocation and of invertases to the stimulation of adventitious root formation in response to a dark pre-exposure of petunia cuttings was investigated, considering the rooting zone (stem base) and the shoot apex as competing sinks. Dark exposure had no effect on photosynthesis and dark respiration during the subsequent light period, but promoted dry matter partitioning to the roots. Under darkness, higher activities of cytosolic and vacuolar invertases were maintained in both tissues when compared to cuttings under light. This was partially associated with higher RNA levels of respective genes. However, activity of cell wall invertases and transcript levels of one cell wall invertase isogene increased specifically in the stem base during the first two days after cutting excision under both light and darkness. During five days after excision, RNA accumulation of four invertase genes indicated preferential expression in the stem base compared to the apex. Darkness shifted the balance of expression of one cytosolic and two vacuolar invertase genes towards the stem base. The results indicate that dark exposure before planting enhances the carbon sink competitiveness of the rooting zone and that expression and activity of invertases contribute to the shift in carbon allocation. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

The effect of different final irrigant activation techniques on the bond strength of an epoxy resin-based endodontic sealer: a preliminary study.

PubMed

Topçuoğlu, Hüseyin Sinan; Tuncay, Öznur; Demirbuga, Sezer; Dinçer, Asiye Nur; Arslan, Hakan

2014-06-01

The aim of this study was to evaluate whether or not different final irrigation activation techniques affect the bond strength of an epoxy resin-based endodontic sealer (AH Plus; Dentsply DeTrey, Konstanz, Germany) to the root canal walls of different root thirds. Eighty single-rooted human mandibular premolars were prepared by using the ProTaper system (Dentsply Maillefer, Ballaigues, Switzerland) to size F4, and a final irrigation regimen using 3% sodium hypochlorite and 17% EDTA was performed. The specimens were randomly divided into 4 groups (n = 20) according to the final irrigation activation technique used as follows: no activation (control), manual dynamic activation (MDA), CanalBrush (Coltene Whaledent, Altststten, Switzerland) activation, and ultrasonic activation. Five specimens from each group were prepared for scanning electron microscopic observation to assess the smear layer removal after the final irrigation procedures. All remaining roots were then obturated with gutta-percha and AH Plus sealer. A push-out test was used to measure the bond strength between the root canal dentin and AH Plus sealer. The data obtained from the push-out test were analyzed using 2-way analysis of variance and Tukey post hoc tests. The bond strength values mostly decreased in the coronoapical direction (P < .001). In the coronal and middle thirds, ultrasonic activiation showed a higher bond strength than other groups (P < .05). In the apical third, MDA displayed the highest bond strength to root dentin (P < .05). The majority of specimens exhibited cohesive failures. The bond strength of AH Plus sealer to root canal dentin may improve with ultrasonic activation in the coronal and middle thirds and MDA in the apical third. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

The self-adjusting file (SAF). Part 3: removal of debris and smear layer-A scanning electron microscope study.

PubMed

Metzger, Zvi; Teperovich, Ehud; Cohen, Raphaela; Zary, Raviv; Paqué, Frank; Hülsmann, Michael

2010-04-01

The aim of this study was to evaluate the cleaning ability of the Self-Adjusting File (SAF) system in terms of removal of debris and smear layer. Root canal preparations were performed in 20 root canals using an SAF operated with a continuous irrigation device. The glide path was initially established using a size 20 K-file followed by the SAF file that was operated in the root canal via a vibrating motion for a total of 4 minutes. Sodium hypochlorite (3%) and EDTA (17%) were used as continuous irrigants and were alternated every minute during this initial 4-minute period. This was followed by a 30-second rinse using EDTA applied through a nonactivated SAF and a final flush with sodium hypochlorite. The roots were split longitudinally and subjected to scanning electron microscopy (SEM). The presence of debris and a smear layer in the coronal, middle, and apical thirds of the canal were evaluated through the analysis of the SEM images using five-score evaluation systems based on reference photographs. The SAF operation with continuous irrigation, using alternating irrigants, resulted in root canal walls that were free of debris in all thirds of the canal in all (100%) of the samples. In addition, smear layer-free surfaces were observed in 100% and 80% of the coronal and middle thirds of the canal, respectively. In the apical third of the canal, smear layer-free surfaces were found in 65% of the root canals. The operation of the SAF system with continuous irrigation coupled with alternating sodium hypochlorite and EDTA treatment resulted in a clean and mostly smear layer-free dentinal surface in all parts of the root canal. Copyright (c) 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Efficacy of different irrigation and activation systems on the penetration of sodium hypochlorite into simulated lateral canals and up to working length: an in vitro study.

PubMed

de Gregorio, Cesar; Estevez, Roberto; Cisneros, Rafael; Paranjpe, Avina; Cohenca, Nestor

2010-07-01

The removal of vital and necrotic pulp tissue, microorganisms, and their toxins is essential for endodontic success. However, the complex anatomy of the root canal system has limited our ability to debride it completely. Hence the purpose of this study was to evaluate the effect of currently used irrigation and activation systems on the penetration of sodium hypochlorite into simulated lateral canals and to working length in a closed system. One hundred single-rooted teeth were used in this study. A total of 600 simulated lateral canals were created, 6 in each tooth, with 2 lateral canals at 2, 4.5, and 6 mm of working length. To resemble the clinical situation, a closed system was created by coating each root with soft modeling wax. Roots were then randomly assigned to 4 experimental groups: group 1 (n = 20), Endoactivator (sonic activation); group 2 (n = 20), passive ultrasonic (PUI) activation; group 3 (n = 20), F file; group 4 (n = 20), apical negative pressure (ANP) irrigation; and control group 5 (n = 20), positive pressure irrigation. The samples were evaluated by direct observation of the images recorded under the dental operating microscope. The results demonstrated that the ANP irrigation group was superior at reaching working length, and PUI was the most effective at lateral canal penetration. The ANP irrigation system demonstrated limited activation of the irrigant into lateral canals but reached the working length significantly more than the other groups tested. In contrast, PUI group demonstrated significantly more penetration of irrigant into lateral canals but not up to the working length. Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

A titration model for evaluating calcium hydroxide removal techniques.

PubMed

Phillips, Mark; McClanahan, Scott; Bowles, Walter

2015-01-01

Calcium hydroxide (Ca(OH)2) has been used in endodontics as an intracanal medicament due to its antimicrobial effects and its ability to inactivate bacterial endotoxin. The inability to totally remove this intracanal medicament from the root canal system, however, may interfere with the setting of eugenol-based sealers or inhibit bonding of resin to dentin, thus presenting clinical challenges with endodontic treatment. This study used a chemical titration method to measure residual Ca(OH)2 left after different endodontic irrigation methods. Eighty-six human canine roots were prepared for obturation. Thirty teeth were filled with known but different amounts of Ca(OH)2 for 7 days, which were dissolved out and titrated to quantitate the residual Ca(OH)2 recovered from each root to produce a standard curve. Forty-eight of the remaining teeth were filled with equal amounts of Ca(OH)2 followed by gross Ca(OH)2 removal using hand files and randomized treatment of either: 1) Syringe irrigation; 2) Syringe irrigation with use of an apical file; 3) Syringe irrigation with added 30 s of passive ultrasonic irrigation (PUI), or 4) Syringe irrigation with apical file and PUI (n=12/group). Residual Ca(OH)2 was dissolved with glycerin and titrated to measure residual Ca(OH)2 left in the root. No method completely removed all residual Ca(OH)2. The addition of 30 s PUI with or without apical file use removed Ca(OH)2 significantly better than irrigation alone. This technique allowed quantification of residual Ca(OH)2. The use of PUI (with or without apical file) resulted in significantly lower Ca(OH)2 residue compared to irrigation alone.

[Influences of micro-irrigation and subsoiling before planting on enzyme activity in soil rhizosphere and summer maize yield.

PubMed

Zhang, Ming Zhi; Niu, Wen Quan; Xu, Jian; Li, Yuan

2016-06-01

In order to explore the influences of micro-irrigation and subsoiling before planting on enzyme activity in soil rhizosphere and summer maize yield, an orthogonal experiment was carried out with three factors of micro-irrigation method, irrigation depth, and subsoiling depth. The factor of irrigation method included surface drip irrigation, subsurface drip irrigation, and moistube-irrigation; three levels of irrigation depth were obtained by controlling the lower limit of soil water content to 50%, 65%, and 80% of field holding capacity, respectively; and three depths of deep subsoiling were 20, 40, and 60 cm. The results showed that the activities of catalase and urease increased first and then decreased, while the activity of phosphatase followed an opposite trend in the growth season of summer maize. Compared with surface drip irrigation and moistube-irrigation, subsurface drip irrigation increased the average soil moisture of 0-80 cm layer by 6.3% and 1.8% in the growth season, respectively. Subsurface drip irrigation could significantly increase soil urease activity, roots volume, and yield of summer maize. With the increase of irrigation level, soil phosphatase activity decreased first and then increased, while urease activity and yield increased first and then decreased. The average soil moisture and root volume all increased in the growth season of summer maize. The increments of yield and root volume from subsoiling of 40 to 20 cm were greater than those from 60 to 40 cm. The highest enzyme activity was obtained with the treatment of subsoiling of 40 cm. In terms of improving water resource use efficiency, nitrogen use efficiency, and crop yield, the best management strategy of summer maize was the combination of subsurface drip irrigation, controlling the lower limit of soil water content to 65% of field holding capacity, and 40 cm subsoiling before planting.

Plant Habitat (PH)

NASA Technical Reports Server (NTRS)

Onate, Bryan

2016-01-01

The International Space Station (ISS) will soon have a platform for conducting fundamental research of Large Plants. Plant Habitat (PH) is designed to be a fully controllable environment for high-quality plant physiological research. PH will control light quality, level, and timing, temperature, CO2, relative humidity, and irrigation, while scrubbing ethylene. Additional capabilities include leaf temperature and root zone moisture and oxygen sensing. The light cap will have red (630 nm), blue (450 nm), green (525 nm), far red (730 nm) and broad spectrum white LEDs. There will be several internal cameras (visible and IR) to monitor and record plant growth and operations.

Effects of Irrigation with Treated Wastewater on Root and Fruit Mineral Elements of Chemlali Olive Cultivar

PubMed Central

Bedbabis, Saida; Ben Rouina, Béchir; Boukhris, Makki

2014-01-01

Twenty-year-old “Chemlali” olive trees trained to vase and rainfed were investigated in either “on” (2004) or “off” (2003) year. A randomized block design with three blocks and three treatments was used and each experimental plot consisted of nine olive trees. Three treatments were applied: (1) rainfed conditions (RF, used as control treatment); (2) irrigation with well water (WW); and (3) irrigation with treated wastewater (TWW). Irrigation with TWW led to a significant increase of root N, P, Ca, Zn, Mn, Na, and Cl concentrations, in particular in the on-year. Data showed significant differences, between the two years, for the concentration of the mineral elements in the roots, with general lower values in the on-year, probably as a consequence of nutrients movement upward in the tree. Fruit N, P, K, Zn, Mn, and Cl contents were significantly higher in TWW irrigated trees with respect to both RF and WW trees, whereas similar values for Ca, Mg, Na, and Cl contents were measured for WW and TWW irrigated trees. The irrigation with TWW allowed to reuse problematic waters and to save nutrients inputs in the olive orchard thus moving towards a more sustainable management of olive orchards in countries where water is the major limiting factor for agriculture. PMID:25013873

Effects of ethylenediaminetetraacetic, etidronic and peracetic acid irrigation on human root dentine and the smear layer.

PubMed

Lottanti, S; Gautschi, H; Sener, B; Zehnder, M

2009-04-01

To evaluate the effects of ethylenediaminetetraacetic (EDTA), etidronic (EA) and peracetic acid (PA) when used in conjunction with sodium hypochlorite (NaOCl) as root canal irrigants on calcium eluted from canals, smear layer, and root dentine demineralization after instrumentation/irrigation. Single-rooted human premolars were irrigated as follows (n = 12 per group): (1) 1% NaOCl during instrumentation, deionized water after instrumentation, (2) 1% NaOCl during, 17% EDTA after instrumentation, (3) a 1 : 1-mixture of 2% NaOCl and 18% EA during and after instrumentation, and (4) 1% NaOCl during, 2.25% PA after instrumentation. Irrigant volumes and contact times were 10 mL/15 min during and 5 mL/3 min after instrumentation. The evaluated outcomes were eluted calcium by atomic absorption spectroscopy, smear-covered areas by scanning electron microscopy in secondary electron mode and apparent canal wall decalcifications on root transsections in backscatter mode. For the smear layer analysis, sclerotic dentine was taken into consideration. Results were compared using appropriate parametric and nonparametric tests, alpha = 0.05. The statistical comparison of the protocols regarding calcium elution revealed that protocol (1) yielded less calcium than (3), which yielded less than protocols (2) and (4). Most of the instrumented canal walls treated with one of the decalcifying agents were free of smear layer. Protocols (1) and (3) caused no decalcification of root dentine, whilst (2) and (4) showed substance typical demineralization patterns. The decalcifying agents under investigation were all able to remove or prevent a smear layer. However, they eroded the dentine wall differently.

Influence of an apical negative pressure irrigation system on bacterial elimination during endodontic therapy: a prospective randomized clinical study.

PubMed

Pawar, Rekha; Alqaied, Abdullah; Safavi, Kamran; Boyko, Jennifer; Kaufman, Blythe

2012-09-01

Recent in vitro studies that use an apical negative pressure irrigation system, EndoVac, have demonstrated promising results in the production of debris-free root canals, while also preventing potential extrusion of irrigants into the periapical region. We conducted a randomized, controlled, prospective clinical study to determine whether the use of EndoVac irrigation (EndoVac group) was more efficient compared with standard needle irrigation (control group) in obtaining canals from which microbes could not be cultivated. Routine endodontic therapy was performed in 48 patients with necrotic, single-rooted, single-canal teeth. The patients were randomly assigned to either the EndoVac group (n = 25) or control group (n = 23). Irrigation with either method was carried out with 0.5% sodium hypochlorite. After surface disinfection, before instrumentation and on completion of chemomechanical preparation, intracanal microbial samples were obtained and cultured under anaerobic conditions. The frequency of microbial cultivability by using either irrigation system was analyzed. The frequency of obtaining culture-negative root canals was 90.9% and 82.6% for the control group and EndoVac group, respectively. There was no significant difference in the antimicrobial efficacy of either control group or EndoVac group (Fisher exact test, P = .665). Furthermore, no significant association between study variables and the irrigation systems' antimicrobial efficacy was found (P > .05). The results of this prospective in vivo study demonstrate that the antimicrobial efficacy of EndoVac irrigation is comparable to that of standard irrigation. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

[Water-saving mechanisms of intercropping system in improving cropland water use efficiency].

PubMed

Zhang, Feng-Yun; Wu, Pu-Te; Zhao, Xi-Ning; Cheng, Xue-Feng

2012-05-01

Based on the multi-disciplinary researches, and in terms of the transformation efficiency of surface water to soil water, availability of cropland soil water, crop canopy structure, total irrigation volume needed on a given area, and crop yield, this paper discussed the water-saving mechanisms of intercropping system in improving cropland water use efficiency. Intercropping system could promote the full use of cropland water by plant roots, increase the water storage in root zone, reduce the inter-row evaporation and control excessive transpiration, and create a special microclimate advantageous to the plant growth and development. In addition, intercropping system could optimize source-sink relationship, provide a sound foundation for intensively utilizing resources temporally and spatially, and increase the crop yield per unit area greatly without increase of water consumption, so as to promote the crop water use efficiency effectively.

Effect of climate change on the irrigation and discharge scheme for winter wheat in Huaibei Plain, China

NASA Astrophysics Data System (ADS)

Zhu, Y.; Ren, L.; Lü, H.

2017-12-01

On the Huaibei Plain of Anhui Province, China, winter wheat (WW) is the most prominent crop. The study area belongs to transitional climate, with shallow water table. The original climate change is complex, in addition, global warming make the climate change more complex. The winter wheat growth period is from October to June, just during the rainless season, the WW growth always depends on part of irrigation water. Under such complex climate change, the rainfall varies during the growing seasons, and water table elevations also vary. Thus, water tables supply variable moisture change between soil water and groundwater, which impact the irrigation and discharge scheme for plant growth and yield. In Huaibei plain, the environmental pollution is very serious because of agricultural use of chemical fertilizer, pesticide, herbicide and etc. In order to protect river water and groundwater from pollution, the irrigation and discharge scheme should be estimated accurately. Therefore, determining the irrigation and discharge scheme for winter wheat under climate change is important for the plant growth management decision-making. Based on field observations and local weather data of 2004-2005 and 2005-2006, the numerical model HYDRUS-1D was validated and calibrated by comparing simulated and measured root-zone soil water contents. The validated model was used to estimate the irrigation and discharge scheme in 2010-2090 under the scenarios described by HadCM3 (1970 to 2000 climate states are taken as baselines) with winter wheat growth in an optimum state indicated by growth height and LAI.

A site-specific agricultural water requirement and footprint estimator (SPARE:WATER 1.0) for irrigation agriculture

NASA Astrophysics Data System (ADS)

Multsch, S.; Al-Rumaikhani, Y. A.; Frede, H.-G.; Breuer, L.

2013-01-01

The water footprint accounting method addresses the quantification of water consumption in agriculture, whereby three types of water to grow crops are considered, namely green water (consumed rainfall), blue water (irrigation from surface or groundwater) and grey water (water needed to dilute pollutants). Most of current water footprint assessments focus on global to continental scale. We therefore developed the spatial decision support system SPARE:WATER that allows to quantify green, blue and grey water footprints on regional scale. SPARE:WATER is programmed in VB.NET, with geographic information system functionality implemented by the MapWinGIS library. Water requirement and water footprints are assessed on a grid-basis and can then be aggregated for spatial entities such as political boundaries, catchments or irrigation districts. We assume in-efficient irrigation methods rather than optimal conditions to account for irrigation methods with efficiencies other than 100%. Furthermore, grey water can be defined as the water to leach out salt from the rooting zone in order to maintain soil quality, an important management task in irrigation agriculture. Apart from a thorough representation of the modelling concept we provide a proof of concept where we assess the agricultural water footprint of Saudi Arabia. The entire water footprint is 17.0 km3 yr-1 for 2008 with a blue water dominance of 86%. Using SPARE:WATER we are able to delineate regional hot spots as well as crop types with large water footprints, e.g. sesame or dates. Results differ from previous studies of national-scale resolution, underlining the need for regional water footprint assessments.

Comparative evaluation of postoperative pain after using endodontic needle and EndoActivator during root canal irrigation: A randomised controlled trial.

PubMed

Ramamoorthi, Surendar; Nivedhitha, Malli Sureshbabu; Divyanand, Madras Jeyaprakash

2015-08-01

The purpose of this study was to evaluate and compare the postoperative level of pain after activation of irrigants using EndoActivator with conventional needle irrigation during root canal therapy. In this prospective randomised clinical trial, 72 symptomatic irreversible pulpitis patients were selected. Based on block randomisation after routine root canal preparation, patients were assigned to two groups. In group EN, procedures were performed with endodontic irrigating needle (n = 36) while group EA received activation using EndoActivator (n = 36) in the final irrigation protocol. All the participants were called through phone at 8, 24 and 48 h to analyse pain score using visual analogue scale. Those patients who developed pain were prescribed ibuprofen 200 mg. Pain score and frequency of tablet intake were recorded and statistically analysed. Results showed that group EA resulted in significantly less postoperative pain and analgesics intake than group EN. In conclusion, within the limitations of this study, the activation of irrigants using EndoActivator can be considered an effective method for reducing postoperative pain. © 2014 Australian Society of Endodontology.

Evaluation of effectiveness of various irrigating solutions on removal of calcium hydroxide mixed with 2% chlorhexidine gel and detection of orange-brown precipitate after removal.

PubMed

Arslan, Hakan; Gok, Tuba; Saygili, Gokhan; Altintop, Hülya; Akçay, Merve; Çapar, Ismail Davut

2014-11-01

The aims of the present study were to evaluate the effect of various irrigating solutions on the removal of calcium hydroxide mixed with 2% chlorhexidine gel from an artificial groove created in a root canal and the generation of orange-brown precipitate in the remaining calcium hydroxide mixed with 2% chlorhexidine gel after irrigation with the various irrigating solutions. The root canals of 48 mandibular premolars were prepared using ProTaper Universal Rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland) up to size F4. The roots were split longitudinally, and a standardized groove was prepared in the apical part of 1 segment. The root halves were reassembled, and calcium hydroxide mixed with 2% chlorhexidine gel medicament was placed into the grooves. The roots were randomly divided into 4 experimental groups specified by the irrigation solution used: 1% NaOCl, 17% EDTA, 7% maleic acid, and 10% citric acid (n = 12). The amount of remaining medicament was evaluated under a stereomicroscope using a 4-grade scoring system. After irrigation, the specimens were also evaluated for the presence/absence of orange-brown precipitate. The effects of the different irrigation solutions on medicament removal were statistically evaluated using the Kruskal-Wallis and Mann-Whitney U tests with Bonferroni correction at a 95% confidence level (P = .0083). Solutions of 7% maleic acid and 10% citric acid were superior to solutions of 1% NaOCl and 17% EDTA in removing calcium hydroxide mixed with 2% chlorhexidine gel (P < .0083). There were no significant differences among the other groups (P > .0083). Orange-brown precipitate was observed in all specimens of the NaOCl group but in no specimens in the other groups. Irrigation solutions of 7% maleic acid and 10% citric acid were more effective in the removal of calcium hydroxide mixed with 2% chlorhexidine gel than those of 1% NaOCl and 17% EDTA. Orange-brown precipitate was found in all specimens of the NaOCl-irrigated groups. However, the precipitate was not observed in specimens in the groups irrigated with 17% EDTA, 7% maleic acid, and 10% citric acid. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Soil water content assessment: critical issues concerning the operational application of the triangle method.

PubMed

Maltese, Antonino; Capodici, Fulvio; Ciraolo, Giuseppe; La Loggia, Goffredo

2015-03-19

Knowledge of soil water content plays a key role in water management efforts to improve irrigation efficiency. Among the indirect estimation methods of soil water content via Earth Observation data is the triangle method, used to analyze optical and thermal features because these are primarily controlled by water content within the near-surface evaporation layer and root zone in bare and vegetated soils. Although the soil-vegetation-atmosphere transfer theory describes the ongoing processes, theoretical models reveal limits for operational use. When applying simplified empirical formulations, meteorological forcing could be replaced with alternative variables when the above-canopy temperature is unknown, to mitigate the effects of calibration inaccuracies or to account for the temporal admittance of the soil. However, if applied over a limited area, a characterization of both dry and wet edges could not be properly achieved; thus, a multi-temporal analysis can be exploited to include outer extremes in soil water content. A diachronic empirical approach introduces the need to assume a constancy of other meteorological forcing variables that control thermal features. Airborne images were acquired on a Sicilian vineyard during most of an entire irrigation period (fruit-set to ripening stages, vintage 2008), during which in situ soil water content was measured to set up the triangle method. Within this framework, we tested the triangle method by employing alternative thermal forcing. The results were inaccurate when air temperature at airborne acquisition was employed. Sonic and aerodynamic air temperatures confirmed and partially explained the limits of simultaneous meteorological forcing, and the use of proxy variables improved model accuracy. The analysis indicates that high spatial resolution does not necessarily imply higher accuracies.

Soil Water Content Assessment: Critical Issues Concerning the Operational Application of the Triangle Method

PubMed Central

Maltese, Antonino; Capodici, Fulvio; Ciraolo, Giuseppe; La Loggia, Goffredo

2015-01-01

Knowledge of soil water content plays a key role in water management efforts to improve irrigation efficiency. Among the indirect estimation methods of soil water content via Earth Observation data is the triangle method, used to analyze optical and thermal features because these are primarily controlled by water content within the near-surface evaporation layer and root zone in bare and vegetated soils. Although the soil-vegetation-atmosphere transfer theory describes the ongoing processes, theoretical models reveal limits for operational use. When applying simplified empirical formulations, meteorological forcing could be replaced with alternative variables when the above-canopy temperature is unknown, to mitigate the effects of calibration inaccuracies or to account for the temporal admittance of the soil. However, if applied over a limited area, a characterization of both dry and wet edges could not be properly achieved; thus, a multi-temporal analysis can be exploited to include outer extremes in soil water content. A diachronic empirical approach introduces the need to assume a constancy of other meteorological forcing variables that control thermal features. Airborne images were acquired on a Sicilian vineyard during most of an entire irrigation period (fruit-set to ripening stages, vintage 2008), during which in situ soil water content was measured to set up the triangle method. Within this framework, we tested the triangle method by employing alternative thermal forcing. The results were inaccurate when air temperature at airborne acquisition was employed. Sonic and aerodynamic air temperatures confirmed and partially explained the limits of simultaneous meteorological forcing, and the use of proxy variables improved model accuracy. The analysis indicates that high spatial resolution does not necessarily imply higher accuracies. PMID:25808771

A Review Over Benefits and Drawbacks of Combining Sodium Hypochlorite with Other Endodontic Materials.

PubMed

Mohammadi, Zahed; Shalavi, Sousan; Moeintaghavi, Amir; Jafarzadeh, Hamid

2017-01-01

As the root canal system considered to be complex and unpredictable, using root canal irrigants and medicaments are essential in order to enhance the disinfection of the canal. Sodium hypochlorite is the most common irrigant in endodontics. Despite its excellent antimicrobial activity and tissue solubility, sodium hypochlorite lacks some important properties such as substantivity and smear layer removing ability. The aim of this review was to address benefits and drawbacks of combining sodium hypochlorite with other root canal irrigants and medicaments. According to the reviewed articles, NaOCl is the most common irrigation solution in endodontics. However, it has some drawbacks such as inability to remove smear layer. One of the drawbacks of NaOCl is its inability to remove the smear layer and lack of substantivity. The adjunctive use of other materials has been suggested to improve NaOCl efficacy. Nevertheless, further studies are required in this field.

Efficacy of 3D conforming nickel titanium rotary instruments in eliminating canal wall bacteria from oval-shaped root canals.

PubMed

Bortoluzzi, Eduardo A; Carlon, Daniel; Meghil, Mohamed M; El-Awady, Ahmed R; Niu, Lina; Bergeron, Brian E; Susin, Lisiane; Cutler, Christopher W; Pashley, David H; Tay, Franklin R

2015-05-01

To evaluate the effectiveness of TRUShape® 3D Conforming Files, compared with Twisted Files, in reducing bacteria load from root canal walls, in the presence or absence of irrigant agitation. Extracted human premolars with single oval-shaped canals were infected with Enterococcus faecalis. Teeth in Group I (N=10; NaOCl and QMix® 2in1 as respective initial and final irrigants) were subdivided into 4 subgroups: (A) TRUShape® instrumentation without irrigant activation; (B) TRUShape® instrumentation with sonic irrigant agitation; (C) Twisted Files without irrigant agitation; (D) Twisted Files with sonic irrigant agitation. To remove confounding factor (antimicrobial irrigants), teeth in Group II (N=10) were irrigated with sterile saline, using the same subgroup designations. Specimens before and after chemomechanical débridement were cultured for quantification of colony-forming units (CFUs). Data from each group were analyzed separately using two-factor ANOVA and Holm-Sidak multiple comparison (α=0.05). Canal wall bacteria were qualitatively examined using scanning electron microscopy (SEM) and light microscopy of Taylor-modified Brown and Brenn-stained demineralised sections. CFUs from subgroups in Group I were not significantly different (P=0.935). For Group II, both file type (P<0.001) and irrigant agitation (P<0.001) significantly affected log-reduction in CFU concentrations. The interaction of these two factors was not significant (P=0.601). Although SEM showed reduced canal wall bacteria, bacteria were present within dentinal tubules after rotary instrumentation, as revealed by light microscopy of longitudinal root sections. TRUShape® files removed significantly more canal wall bacteria than Twisted Files when used without an antibacterial irrigant; the latter is required to decontaminate dentinal tubules. Root canal disinfection should not be focused only on a mechanistic approach. Rather, the rational choice of a rotary instrumentation system should be combined with the use of well-tested antimicrobial irrigants and delivery/agitation techniques to establish a clinically realistic chemomechanical débridement protocol. Published by Elsevier Ltd.

Modelling the impact of mulching the soil with plant remains on water regime formation, crop yield and energy costs in agricultural ecosystems

NASA Astrophysics Data System (ADS)

Gusev, Yeugeniy M.; Dzhogan, Larisa Y.; Nasonova, Olga N.

2018-02-01

The model MULCH, developed by authors previously for simulating the formation of water regime in an agricultural field covered by straw mulch layer, has been used for the comparative evaluation of the efficiency of four agricultural cultivation technologies, which are usually used for wheat production in different regions of Russia and Ukraine. It simulates the dynamics of water budget components in a soil rooting zone at daily time step from the beginning of spring snowmelt to the beginning of the period with stable negative air temperatures. The model was designed for estimation of mulching efficiency in terms of increase in plant water supply and crop yield under climatic and soil conditions of the steppe and forest-steppe zones. It is used for studying the mulching effect on some characteristics of water regime and yield of winter wheat growing at specific sites located in semi-arid and arid regions of the steppe and forest-steppe zones of the eastern and southern parts of the East-European (Russian) plain. In addition, a previously developed technique for estimating the energetic efficiency of various agricultural technologies with accounting for their impact on changes in soil energy is applied for the comparative evaluation of the efficiency of four agricultural cultivation technologies, which are usually used for wheat production in different regions of the steppe and forest-steppe zones of the European Russia: (1) moldboard tillage of soil without irrigation, (2) moldboard tillage of soil with irrigation, (3) subsurface cultivation, and (4) subsurface cultivation with mulching the soil with plant remains.

Effectiveness of various irrigation protocols for the removal of calcium hydroxide from artificial standardized grooves

PubMed Central

GOKTURK, Hakan; OZKOCAK, Ismail; BUYUKGEBIZ, Feyzi; DEMIR, Osman

2017-01-01

Abstract Objective The aim of this study was to investigate the ability of laser-activated irrigation (LAI), XP-endo Finisher, CanalBrush, Vibringe, passive ultrasonic irrigation (PUI), and conventional syringe irrigation systems on the removal of calcium hydroxide (CH) from simulated root canal irregularities. Material and Methods The root canals of one hundred and five extracted single-rooted teeth were instrumented using Reciproc rotary files up to size R40. The teeth were split longitudinally. Two of the three standard grooves were created in the coronal and apical section of one segment, and another in the middle part of the second segment. The standardized grooves were filled with CH and the root halves were reassembled. After 14 days, the specimens were randomly divided into 7 experimental groups (n=15/group). CH was removed as follows: Group 1: beveled needle irrigation; Group 2: double side-vented needle irrigation; Group 3: CanalBrush; Group 4: XP-endo Finisher; Group 5: Vibringe; Group 6: PUI; Group 7: LAI. The amount of remaining CH in the grooves was scored under a stereomicroscope at 20× magnification. Statistical evaluation was performed using Kruskal–Wallis and Bonferroni-Correction Mann–Whitney U tests. Results Groups 1 and 2 were the least efficient in eliminating CH from the grooves. Groups 6 and 7 eliminated more CH than the other protocols; however, no significant differences were found between these two groups (P>.05). Conclusions Nevertheless, none of the investigated protocols were able to completely remove all CH from all three root regions. LAI and PUI showed less residual CH than the other protocols from artificial grooves. PMID:28678948

[Regulation effect of water storage in deeper soil layers on root physiological characteristics and leaf photosynthetic traits of cotton with drip irrigation under mulch].

PubMed

Luo, Hong-Hai; Zhang, Hong-Zhi; Du, Ming-Wei; Huang, Jian-Jun; Zhang, Ya-Li; Zhang, Wang-Feng

2009-06-01

A soil column culture experiment was conducted under the ecological and climatic conditions of Xinjiang to study the effects of water storage in deeper (> 60 cm) soil layers on the root physiological characteristics and leaf photosynthetic traits of cotton variety Xinluzao 13. Two treatments were installed, i.e., well-watered and no watering. The moisture content in plough layer was controlled at 70% +/- 5% and 55% +/- 5% of field capacity by drip irrigation under mulch during growth season. It was shown that the water storage in deeper soil layers enhanced the SOD activity and the vigor of cotton root, and increased the water use efficiency of plant as well as the leaf water potential, chlorophyll content, and net photosynthesis rate, which finally led to a higher yield of seed cotton and higher water use efficiency. Under well-watered condition and when the moisture content in plough layer was maintained at 55% of field capacity, the senescence of roots in middle and lower soil layers was slower, and the higher root vigor compensated the negative effects of impaired photosynthesis caused by water deficit to some extent. The yield of seed cotton was lower when the moisture content in plough layer was maintained at 55% of field capacity than at 70% of field capacity, but no significant difference was observed in the water use efficiency. Our results emphasized the importance of pre-sowing irrigation in winter or in spring to increase the water storage of deeper soil layers. In addition, proper cultivation practices and less frequent drip irrigation (longer intervals between successive rounds of irrigation) were also essential for conserving irrigation water and achieving higher yield.

Smear layer removal evaluation of different protocol of Bio Race file and XP- endo Finisher file in corporation with EDTA 17% and NaOCl.

PubMed

Zand, Vahid; Mokhtari, Hadi; Reyhani, Mohammad-Frough; Nahavandizadeh, Neda; Azimi, Shahram

2017-11-01

The aim of the present study was to compare the amount of the smear layer remaining in prepared root canals with different protocols of Bio RaCe files and XP-endo Finisher file (XPF) in association with 17% EDTA and sodium hypochlorite solution. A total of 68 extracted single-rooted teeth were randomly divided into 4 experimental groups (n=14) and two control groups (n=6). The root canals were prepared with Bio RaCe files (FKG Dentaire, Switzerland) using the crown-down technique based on manufacturer's instructions and irrigated according to the following irrigation techniques: Group 1: XPF with 2 mL of 2.5% NaOCl for 1 minute. Group 2:, XPF with 1 mL of 17% EDTA for one minute. Group 3: XPF was used for 1 minute in association with normal saline solution. Group 4: XP-endo Finisher file for 30 seconds in association with 2.5% NaOCl and 17% EDTA for 30 seconds. The negative control group: NaOCl (2.5%) was used during root canal preparation, followed by irrigation with 17% EDTA at the end of root canal preparation. The positive control group: Normal saline solution was used for irrigation during root canal preparation. In all the groups, during preparation of the root canals with Bio RaCe file, 20 mL of 2.5% NaOCl was used for root canal irrigation and at the end of the procedural steps 20 mL of normal saline solution was used as a final irrigant. The samples were analyzed under SEM at ×1000‒2000 magnification and evaluated using Torabinejad scoring system. Data were analyzed with non-parametric Kruskal-Wallis test and post hoc Mann-Whitney U test, using SPSS. Statistical significant was defined at P <0.05. The results of the study showed the least amount of the smear layer at coronal, middle and apical thirds of the root canals in groups 2, which was not significantly different from the negative control group ( P <0.5). Under the limitations of the present study, use of a combination of NaOCl and EDTA in association with XPF exhibited the best efficacy for the removal of the smear layer. Key words: Smear layer, XP-endo Finisher file, EDTA, Sodium hypochlorite.

Uptake and distribution of bisphenol A and nonylphenol in vegetable crops irrigated with reclaimed water.

PubMed

Lu, Jian; Wu, Jun; Stoffella, Peter J; Wilson, P Chris

2015-01-01

The potential uptake and distribution of bisphenol A (BPA) and nonylphenol (NP) (from reclaimed irrigation water) in edible crops was investigated. BPA and NP were spiked into simulated reclaimed water at environmentally relevant concentrations. Two crops (lettuce, Lactuca sativa and tomato, Lycopersicon esculentum) were grown hydroponically in a greenhouse using the spiked irrigation water under two irrigation exposure scenarios (overhead foliar exposure and subsurface root exposure). BPA concentrations in tomato fruit were 26.6 ± 5.8 (root exposure) and 18.3 ± 3.5 (foliar exposure) μg kg(-1), while concentrations in lettuce leaves were 80.6 ± 23.1 (root exposure) and 128.9 ± 17.4 (foliar exposure) μg kg(-1). NP concentrations in tomato fruit were 46.1 ± 6.6 (root exposure) and 24.6 ± 6.4 (foliar exposure) μg kg(-1), while concentrations in lettuce leaves were 144.1 ± 9.2 (root exposure) and 195.0 ± 16.9 (foliar exposure) μg kg(-1). BPA was relatively mobile in lettuce plants regardless of exposure route. Limited mobility was observed for NP in both crops and BPA in tomatoes. The estimated daily intake of BPA and NP through consumption of vegetables irrigated with reclaimed water ranged from 8.9-62.9 to 11.9-95.1 μg, respectively, depending on the exposure route. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of post-space treatment on retention of fiber posts in different root regions using two self-etching systems.

PubMed

Zhang, Ling; Huang, Li; Xiong, Yu; Fang, Ming; Chen, Ji-Hua; Ferrari, Marco

2008-06-01

The effect of post-space treatment on the retention of fiber posts in different root regions was evaluated using two self-etching systems. Post spaces were prepared in extracted premolars and then the root canals were subjected to one of the following post-space treatments: (i) water irrigation (control); (ii) etching with 35% phosphoric acid for 30 s; (iii) irrigation with 17% EDTA followed by 5.25% sodium hypochlorite (NaOCl); and (iv) ultrasonic agitation associated with 17% EDTA and 5.25% NaOCl irrigating solutions. The dentin surfaces were examined under scanning electron microscopy (SEM) after different post-space treatments. Fiber posts were then luted in the treated roots using resin cement with either Clearfil SE Bond or Clearfil DC Bond, and the thin-slice push-out test was performed. Scanning electron microscopy showed that all the post-space treatments tested were effective in removal of the smear layer of debris, or sealer/gutta-percha remnants, on the root canal. The apical push-out strength was affected by post-space treatment. Both 35% phosphoric acid etching and ultrasonic agitation in combination with EDTA/NaOCl irrigation improved the apical push-out strength of the fiber post, regardless of the type of self-etching system. A solo irrigation with an EDTA/NaOCl solution resulted in a lower apical push-out strength compared with the other two experimental groups.

The Effect of Sodium Hypochlorite and Chlorhexidine as Irrigant Solutions for Root Canal Disinfection: A Systematic Review of Clinical Trials.

PubMed

Gonçalves, Lucio Souza; Rodrigues, Renata Costa Val; Andrade Junior, Carlos Vieira; Soares, Renata G; Vettore, Mario Vianna

2016-04-01

This systematic review aimed to compare the effectiveness of sodium hypochlorite and chlorhexidine for root canal disinfection during root canal therapy. A literature search for clinical trials was made on the PubMed (MEDLINE), Web of Knowledge, SCOPUS, and Science Direct databases and in the reference lists of the identified articles up to January 2015. Quality assessment of the selected studies was performed according to the Consolidated Standards of Reporting Trials statement. One clinical trial and 4 randomized clinical trials were selected from the 172 articles initially identified. There was heterogeneity in the laboratory methods used to assess the root canal disinfection as well as in the concentrations of the irrigants used. Therefore, meta-analysis was not performed. Two studies reported effective and similar reductions in bacterial levels for both irrigants. Sodium hypochlorite was more effective than chlorhexidine in reducing microorganisms in 1 study, and another reported opposite findings. Both root irrigants were ineffective in eliminating endotoxins from necrotic pulp root canals in 1 study. Trial design and information regarding randomization procedures were not clearly described in the clinical trials. No study compared laboratory results with clinical outcomes. The available evidence on this topic is scarce, and the findings of studies were not consistent. Additional randomized clinical trials using clinical outcomes to compare the use of sodium hypochlorite and chlorhexidine during root canal therapy are needed. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

[Analysis of different endodontic sealers and strategies of root canal irrigation on the bond strength of fiber posts].

PubMed

Zhu, Shujin; Liu, Cuiling; Zheng, Zheng; Yang, Liyuan; Gao, Xu

2015-06-01

To evaluate the influence of eugenol-containing and resin-containing endodontic sealers on the bond strength of fiber posts using different strategies of root canal irrigation. Forty-eight mandibular premolars were endodontically treated. The specimens were randomly assigned into two groups according to different endodontic sealers. Group A used Endofil (eugenol-containing endodontic sealer), and group B used AH-plus (resin-containing endodontic sealer). After post space preparation, each group was randomly assigned into three subgroups according to the strategies of root canal irrigation (eight premolars in each subgroup). Group Al and B1: 0.9%NaCl irrigation; Group A2 and B2: 17% ethylene diamine tetraacetic acid (EDTA)+5.25%NaClO+0.9%NaCl irrigation; Group A3 and B3: ultrasonic agitation associated with 1 7%EDTA+5.25%NaClO+0.9%NaCl. One week after the cementation of fiber posts using RelyX™ Unicem, a push-out test was performed to measure the bond strength of the posts. The microstructure of the root canal surface was examined under scanning electron microscope (SEM). The bond strengths of the six groups were as follows: Al (7.96±2.23) MPa, A2 (9.95±2.89) MPa, A3 (18.88±3.69) MPa, B1 (11.41±3.71) MPa, B2 (14.00±4.04) MPa, and B3 (19.14±3.27) MPa. Statistical analysis revealed a significant interaction between the different endodontic sealers and the strategies of root canal irrigation (P<0.05). Lower bond strength was found in group Al but not in group BI (P<0.05), and the same result was revealed when comparing group A2 and B2. No significant difference was observed between group A3 and B3 (P>0.05). SEM showed that the root canal in group A3 and B3 achieved the cleanest surface with nearly all dentine tubules opened. The eugenol-containing endodontic sealer can impair the bond strength of fiber posts compared with the resin-containing sealer when the root canal is irrigated by 0.9% NaCl or 17%EDTA+5.25%NaClO+0.9%NaC. No difference was observed between the two sealers when using 17%EDTA+5.25% NaCIO+0.9%NaCl combined with ultrasonic irrigation.

Efficacy of low concentrations of sodium hypochlorite and low-powered Er,Cr:YSGG laser activated irrigation against an Enterococcus faecalis biofilm.

PubMed

Christo, J E; Zilm, P S; Sullivan, T; Cathro, P R

2016-03-01

To establish the antibacterial efficacy of low concentrations of sodium hypochlorite with and without Er,Cr:YSGG laser activation on Enterococcus faecalis biofilms in extracted teeth. The root canals of 96 decoronated single-rooted extracted human teeth were prepared to a size 40, 0.06 taper 1 mm beyond the apex. They were mounted within a flow cell, which was sterilized before pumping a nutrient media through the root canals. The flow cell was inoculated with E. faecalis (ATCC 700802) and cultivated for 4 weeks. The root-ends were sealed, and the roots were then subjected to one of six treatment groups: group 1: syringe irrigation (SI) with saline (control) using a 27 -gauge Monoject needle 1 mm from the apex for 2 min; group 2: as for group 1 but with 1% NaOCl; group 3: as for group 1 but with 4% NaOCl; group 4: 0.5% NaOCl irrigation for 15 s followed by laser-activated irrigation (LAI) with four 15-s cycles replenishing the irrigant between cycles; group 5: as for group 4 but with 1% NaOCl as the irrigant; group 6: as for group 4 but with 4% NaOCl as the irrigant. Following treatment, teeth were crushed and viable bacteria were quantitated by serial dilution and plating. The colony-forming unit values were compared between groups using one-way anova and Tukey-adjusted post hoc tests. A two-tailed P value of <0.05 was considered statistically significant. The mean number of cells recovered from the 1% NaOCl SI group was significantly higher than that from the 4% NaOCl LAI group (P = 0.02). Within the limitations of this laboratory study, low-powered (0.5 W) Er,Cr:YSGG laser activation did not improve the antibacterial effect of low concentrations of sodium hypochlorite. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Biomass Accumulation, Photosynthetic Traits and Root Development of Cotton as Affected by Irrigation and Nitrogen-Fertilization

PubMed Central

Chen, Zongkui; Tao, Xianping; Khan, Aziz; Tan, Daniel K. Y.; Luo, Honghai

2018-01-01

Limitations of soil water and nitrogen (N) are factors which cause a substantial reduction in cotton (Gossypium hirsutum L.) yield, especially in an arid environment. Suitable management decisions like irrigation method and nitrogen fertilization are the key yield improvement technologies in cotton production systems. Therefore, we hypothesized that optimal water-N supply can increase cotton plant biomass accumulation by maintaining leaf photosynthetic capacity and improving root growth. An outdoor polyvinyl chloride (PVC) tube study was conducted to investigate the effects of two water-N application depths, i.e., 20 cm (H20) or 40 cm (H40) from soil surface and four water-N combinations [deficit irrigation (W55) and no N (N0) (W55N0), W55 and moderate N (N1) (W55N1), moderate irrigation (W75) and N0 (W75N0), W75N1] on the roots growth, leaf photosynthetic traits and dry mass accumulation of cotton crops. H20W55N1 combination increased total dry mass production by 29–82% and reproductive organs biomass by 47–101% compared with other counterparts. Root protective enzyme and nitrate reductase (NR) activity, potential quantum yield of photosystem (PS) II (Fv/Fm), PSII quantum yield in the light [Y(II)] and electron transport rate of PSII were significantly higher in H20W55N1 prior to 82 days after emergence. Root NR activity and protective enzyme were significantly correlated with chlorophyll, Fv/Fm, Y(II) and stomatal conductance. Hence, shallow irrigation (20 cm) with moderate irrigation and N-fertilization application could increase cotton root NR activity and protective enzyme leading to enhance light capture and photochemical energy conversion of PSII before the full flowering stage. This enhanced photoassimilate to reproductive organs. PMID:29497435

Comparative analysis of endodontic smear layer removal efficacy of 17% ethylenediaminetetraacetic acid, 7% maleic acid, and 2% chlorhexidine using scanning electron microscope: An in vitro study.

PubMed

Attur, Kailash; Joy, Mathew T; Karim, Riyas; Anil Kumar, V J; Deepika, C; Ahmed, Haseena

2016-08-01

The aim of the present study was to evaluate the efficiency of different endodontic irrigants in the removal of smear layer through scanning electron microscopic image analysis. The present in vitro study was carried out on 45 single-rooted extracted human mandibular premolar teeth with single canal and complete root formation. Teeth were randomly assigned to three groups with 15 teeth in each group. Group I samples were irrigated with 17% ethylenediaminetetraacetic (EDTA) irrigation, Group II with 7% maleic acid irrigation, and Group III with 2% chlorhexidine irrigation. Scanning electron microscope evaluation was done for the assessment of smear layer removal in the coronal, middle, and apical thirds. Comparison of the smear layer removal between the three different groups was done by Kruskal-Wallis test, followed by Mann-Whitney U test for comparing individual groups. A P value less than 0.05 was considered to be statistically significant. Statistically significant difference was seen between the two test groups (17% EDTA vs. 7% maleic acid and 17% EDTA vs. 2% chlorhexidine) in smear layer removal at coronal, middle, and apical thirds of the root canal. The most efficient smear layer removal was seen in Group I with 17% EDTA irrigation compared with other groups (P < 0.05) and the least by 2% chlorhexidine. The present study shows that 17% EDTA efficiently removes the smear layer from root canal walls.

Temporal variations in reference evapotranspiration in Hubei Province, China, from 1960 to 2014

NASA Astrophysics Data System (ADS)

Wu, Hao; Wang, Xiugui; Wang, Yan; Xu, Yaxin; Han, Xudong

2018-01-01

Reference evapotranspiration (ET0) plays a critical role in irrigation planning and is also important for hydrological cycle, environmental, and other studies. Thus, this research examined the trends in ET0 on seasonal and annual timescales in Hubei Province, China. ET0 was estimated using the Penman Monteith method (P-M) at 16 meteorological stations located in different areas of Hubei Province during the period 1960-2014. The trends in seasonal and annual ET0 were investigated using the Mann-Kendall test and Sen's slope estimator. The periodicities of ET0 in different regions were investigated using wavelet analysis. The major meteorological factors affecting ET0 were investigated using partial correlation analysis and the contribution rate method. The results showed, on a seasonal timescale, that in spring, ET0 increased in all geographic zones. In summer, ET0 decreased in all geographic zones. In autumn and winter, ET0 displayed no significant changes in any of the geographic zones. On an annual timescale, ET0 decreased in all geographic zones, and the magnitudes of the negative trend in annual ET0 were 2.58-10.04 mm 10a-1. In the five geographic zones, the periodic characteristics of ET0 were identical; the significant wavelet power spectra of ET0 had 3-7, 13-17, and 24-32-year modulations in variation. Among the meteorological factors, sunshine hours were the major climate element that influenced the variability in ET0. The results will provide important references for scientific planning for agriculture, water resource allocation, and water-saving irrigation.

Effects of application methods of metam sodium and plastic covers on horizontal and vertical distributions of methyl isothiocyanate in bedded field plots.

PubMed

Ou, Li-Tse; Thomas, John E; Allen, L Hartwell; Vu, Joseph C; Dickson, Donald W

2006-08-01

This study was conducted to examine the effects of three application methods of metam sodium (broadcast, single irrigation drip tape delivery, and double irrigation drip tape delivery) and two plastic covers (polyethylene film and virtually impermeable film) on volatilization and on horizontal and vertical distributions of the biologically active product of metam sodium, methyl isothiocyanate (MITC), in field plots in a Florida sandy soil. Volatilization of MITC from field beds lasted for about 20 hours after completion of metam sodium application regardless of application methods. Virtually impermeable film (VIF) was a better barrier to reduce volatilization loss than polyethylene film (PE). Since water was not applied during broadcast application, MITC was mainly retained in the shallow soil layer (0- to 20-cm depth) and downward movement of MITC was limited to about 30 cm. Large values of standard deviation indicated that initial spatial distribution of MITC in the root zone (10- and 20-cm depths) of the two broadcast applied beds covered with PE or VIF was variable. Twice more water was delivered through the single drip tape than through individual tapes of double drip tape treatments during drip application of metam sodium. More water from the single drip tape likely facilitated downward movement of MITC to at least 60-cm depth, but MITC did not penetrate to this depth in the double drip tape beds. On the other hand, horizontal distribution of MITC in the root zone (10- and 20-cm depths) in the double drip tape beds was more uniform than in the single drip tape beds. More MITC was retained in the subsurface of the VIF-covered beds regardless of application methods than in the PE-covered beds.

Immobilization remediation of Cd-polluted soil with different water condition.

PubMed

Li, Jianrui; Xu, Yingming

2017-05-15

To demonstrate effects of water management on soil Cd immobilization using palygorskite, the investigation evaluated impacts of palygorskite on uptake of Cd present in soils with different water condition by rice plant. Pot experiment results showed that, pH, available Fe and P in untreated soils were higher in continuous flooding than in traditional irrigation and wetting irrigation, which were reasons for lower soil exchangeable Cd and plant Cd in continuous flooding. In control group (untreated soils), compared to traditional irrigation, continuous flooding reduced brown rice Cd by 37.9%, that in wetting irrigation increased by 31.0%. At palygorskite concentrations of 5 g kg -1 , 10 g kg -1 and 15 g kg -1 , brown rice Cd reduced by 16.7%, 44.4% and 55.6% under continuous flooding, 13.8%, 34.5% and 44.8% under traditional irrigation, 13.1%, 36.8% and 47.3% under wetting irrigation (p < 0.05). At the same palygorskite addition, decreasing amplitude of brown rice Cd was higher in continuous flooding than in traditional irrigation and wetting irrigation. Competition for adsorption sites in root coating between Cd 2+ and Fe 2+ was another factor governing plant Cd. In control group, compared to traditional irrigation, root coating Fe(II) increased by 124.5% and root coating Cd reduced by 17.6% upon continuous flooding (p < 0.05). In conclusion, palygorskite addition combined with continuous flooding was an efficacious technique to stabilize Cd in paddy soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

A combined monitoring and modeling approach to quantify water and nitrate leaching using effective soil column hydraulic properties

NASA Astrophysics Data System (ADS)

Couvreur, V.; Kandelous, M. M.; Moradi, A. B.; Baram, S.; Mairesse, H.; Hopmans, J. W.

2014-12-01

There is a worldwide growing concern for agricultural lands input to groundwater pollution. Nitrate contamination of groundwater across the Central Valley of California has been related to its diverse and intensive agricultural practices. However, there has been no study comparing leaching of nitrate in each individual agricultural land within the complex and diversely managed studied area. A combined field monitoring and modeling approach was developed to quantify from simple measurements the leaching of water and nitrate below the root zone. The monitored state variables are soil water content at several depths within the root zone, soil matric potential at two depths below the root zone, and nitrate concentration in the soil solution. In the modeling part, unsaturated water flow and solute transport are simulated with the software HYDRUS in a soil profile fragmented in up to two soil hydraulic types, whose effective hydraulic properties are optimized with an inverse modeling method. The applicability of the method will first be demonstrated "in-silico", with synthetic soil water dynamics data generated with HYDRUS, and considering the soil column as the layering of several soil types characterized in-situ. The method will then be applied to actual soil water status data from various crops in California including tomato, citrus, almond, pistachio, and walnut. Eventually, improvements of irrigation and fertilization management practices (i.e. mainly questions of quantity and frequency of application minimizing leaching under constraint of water and nutrient availability) will be investigated using coupled modeling and optimization tools.

Effectiveness of different final irrigation protocols in removing debris in flattened root canals.

PubMed

Nadalin, Michele Regina; Perez, Danyel Elias da Cruz; Vansan, Luiz Pascoal; Paschoala, Cristina; Souza-Neto, Manoel Damião; Saquy, Paulo César

2009-01-01

This study evaluated in vitro the capacity of debris removal from the apical third of flattened root canals, using different final irrigation protocols. Thirty human mandibular central incisors with a mesiodistal flattened root were prepared using rotary instrumentation by Endo-Flare 25.12 and Hero 642 30.06, 35.02, 40.02 files, irrigated with 2 mL of 1% NaOCl after each file. The specimens were randomly distributed into 5 groups according to the final irrigation of root canals: Group I: 10 mL of distilled water (control), Group II: 10 mL of 1% NaOCl for 8 min, Group III: 2 mL of 1% NaOCl for 2 min (repeated 4 times), Group IV: 10 mL of 2.5% NaOCl for 8 min, and Group V: 10 mL of 2.5% NaOCl for 2 min (repeated 4 times). The apical thirds of the specimens were subjected to histological processing and 6-microm cross-sections were obtained and stained with hematoxylin-eosin. The specimens were examined under optical microscopy at x40 magnification and the images were subjected to morphometric analysis using the Scion image-analysis software. The total area of root canal and the area with debris were measured in square millimeters. Analysis of variance showed no statistically significant difference (p>0.05) among the groups GI (2.39 +/- 3.59), GII (2.91 +/- 2.21), GIII (0.73 +/- 1.36), GIV (0.95 +/- 0.84) and GV (0.51 +/- 0.22). In conclusion, the final irrigation protocols evaluated in this study using the Luer syringe presented similar performance in the removal of debris from the apical third of flattened root canals.

Effect of endodontic irrigation with 1% sodium hypochlorite and 17% EDTA on primary teeth: a scanning electron microscope analysis.

PubMed

Ximenes, Marcos; Triches, Thaisa C; Beltrame, Ana Paula C A; Hilgert, Leandro A; Cardoso, Mariane

2013-01-01

This study evaluated the efficacy of 2 final irrigation solutions for removal of the smear layer (SL) from root canals of primary teeth, using scanning electron microscope (SEM) analysis. Thirty primary molars were selected and a single operator instrumented the canals. The initial irrigation was done with a 1% sodium hypochlorite (NaOCl) solution. After the preparation, the roots were randomly divided into 3 groups for final irrigation: Group 1, 1% NaOCl (n = 10); Group 2, 17% EDTA + 1% NaOCl (n = 10); and Group 3, 17% EDTA + saline solution (n = 10). The roots were prepared for SEM analysis (magnification 1000X). The photomicrographs were independently analyzed by 2 investigators with SEM experience, attributing scores to each root third in terms of SL removal. Kruskal-Wallis and Mann-Whitney tests revealed that there was no statistical difference between the groups (P = 0.489). However, a statistical difference was found (P < 0.05) in a comparison of root thirds, with the apical third having the worst results. Comparing the thirds within the same group, all canals showed statistical differences between the cervical and apical thirds (P < 0.05). The authors determined that no substance or association of substances were able to completely remove SL.

Model assessing thermal changes during high temperature root canal irrigation

PubMed Central

Bartolo, Analise; Koyess, Edmond; Micallef, Christopher

2016-01-01

The main aim of root canal irrigation is to eliminate micro-organisms. Sodium hypochlorite (NaOCl) is considered to be the ideal material and raising its temperature potentiates the antimicrobial activity. NaOCl may lead to localised tissue necrosis when extruded past the root apex. This study analyses the use of high temperature root canal irrigation as an alternative process for the elimination of microorganisms from the root canal system. An experimental set-up was designed where a constant supply of heat was passed from a heat source through a copper wire inside the root canal. The data acquired together with known constants pertaining to enamel and dentine was used to numerically model the thermal changes in a tooth using a finite element method. Results obtained from the finite element thermal model of the tooth were repeatable and were validated with the experimental results. The thermo-physical properties of the tooth were varied and convergence criteria met. The temperatures reached were below what has been reported to cause irreversible damage to the bone. This was further confirmed from a series of simulations that were undertaken. The temperatures achieved were suitable for the elimination of microorganisms during root canal therapy. PMID:27733934

Measurement of pressure changes during laser-activated irrigant by an erbium, chromium: yttrium, scandium, gallium, garnet laser.

PubMed

Peeters, Harry Huiz; De Moor, Roeland J G

2015-07-01

The use of Er,Cr:YSGG laser to activate irrigants results in the creation of vapour bubbles and shockwaves. The present study evaluated the magnitude of pressure changes in the root canal during laser-activated irrigation. The root canal of a single extracted maxillary canine was enlarged to a size 40/0.06 file. A pressure sensor was inserted apically into the root canal. The tooth was processed as follows. In the EDTA condition, the tooth was irrigated with 17 % EDTA; in the NaOCl condition, the tooth was irrigated with 3 % NaOCl. In all conditions, the irrigants were activated at 0.75 and 1.75 W for 60 s using RFT2 and MZ2 tips; to analyse the effect of tip placement, the tip was activated at the orifice and after inserting the tip 5 mm deeper than the orifice. Data showed no significant difference between irrigation regimens (p > 0.05). There were no significant differences of the pressure between RFT2 and MZ2 tips (p > 0.05). The placement of tips closer to the apex resulted in significantly higher pressure than at the orifice (p < 0.001). The use of 1.75 W power resulted in a significantly higher increase of pressure compared to 0.75 W (p < 0.001), regardless either the type of solutions or tips used. The magnitude of the pressure changes in the root canal at 0.75 W was significantly lower than 1.75 W regardless of either type of tips or solutions used. The closer the insertion of the tip to the apex, the higher the pressure.

Effectiveness of root canal debris removal using passive ultrasound irrigation with chlorhexidine digluconate or sodium hypochlorite individually or in combination as irrigants.

PubMed

Ferreira, Rafael Brandao; Marchesan, Melissa Andreia; Silva-Sousa, Yara Teresinha; Sousa-Neto, Manoel

2008-07-01

The aim of this in vitro study was to evaluate the cleaning capacity of different auxiliary chemical substances energized with ultrasound in radicular dentin using morphologic analysis. Twenty-eight single-canal, mandibular incisors were prepared with the Hero 642 canal preparation system following the sequence: 25/12, 30/06, 35/02, and 40/02, 1 mm from the apex. The specimens were then divided into four groups of seven teeth. During biomechanical preparation the teeth were irrigated with 2 ml of distilled water between files. Each group of specimens (n=7) received a final irrigation with 100 ml of the following irrigants that were activated with ultrasound for 3 minutes: Group 1- distilled water; Group 2- 0.2% chlorhexidine digluconate (CHX); Group 3- 2.5% sodium hypochlorite (NaOCl); and Group 4-the filtrate obtained after combining 0.2% CHX and 2.5% NaOCl. The apical portions of the root canals from each group were then submitted to histological processing and analyzed using optical microscopy. Results showed statistical differences between the groups (p<0.01). Groups 1 and 2 (distilled water and 0.2% CHX respectively) were statistically similar in terms of a greater amount of debris, whereas 2.5% NaOCl and the filtrate were more efficient in removal of debris. There is no additional benefit in terms of debris removal from root canal walls by irrigating with the filtrate obtained from the combination of NaOCl and CHX when compared to using NaOCl alone. The findings of this study suggest the time and expense of preparing and using a combination of NaOCl and CHX is not warranted compared to using NaOCl alone for root canal irrigation.

Auxin distribution is differentially affected by nitrate in roots of two rice cultivars differing in responsiveness to nitrogen

PubMed Central

Song, Wenjing; Sun, Huwei; Li, Jiao; Gong, Xianpo; Huang, Shuangjie; Zhu, Xudong; Zhang, Yali; Xu, Guohua

2013-01-01

Background and Aims Although ammonium (NH4+) is the preferred form of nitrogen over nitrate (NO3−) for rice (Oryza sativa), lateral root (LR) growth in roots is enhanced by partial NO3− nutrition (PNN). The roles of auxin distribution and polar transport in LR formation in response to localized NO3− availability are not known. Methods Time-course studies in a split-root experimental system were used to investigate LR development patterns, auxin distribution, polar auxin transport and expression of auxin transporter genes in LR zones in response to localized PNN in ‘Nanguang’ and ‘Elio’ rice cultivars, which show high and low responsiveness to NO3−, respectively. Patterns of auxin distribution and the effects of polar auxin transport inhibitors were also examined in DR5::GUS transgenic plants. Key Results Initiation of LRs was enhanced by PNN after 7 d cultivation in ‘Nanguang’ but not in ‘Elio’. Auxin concentration in the roots of ‘Nanguang’ increased by approx. 24 % after 5 d cultivation with PNN compared with NH4+ as the sole nitrogen source, but no difference was observed in ‘Elio’. More auxin flux into the LR zone in ‘Nanguang’ roots was observed in response to NO3− compared with NH4+ treatment. A greater number of auxin influx and efflux transporter genes showed increased expression in the LR zone in response to PNN in ‘Nanguang’ than in ‘Elio’. Conclusions The results indicate that higher NO3− responsiveness is associated with greater auxin accumulation in the LR zone and is strongly related to a higher rate of LR initiation in the cultivar ‘Nanguang’. PMID:24095838

Analysis of the relationship between the volumetric soil moisture content and the NDVI from high resolution multi-spectral images for definition of vineyard management zones to improve irrigation

NASA Astrophysics Data System (ADS)

Martínez-Casasnovas, J. A.; Ramos, M. C.

2009-04-01

As suggested by previous research in the field of precision viticulture, intra-field yield variability is dependent on the variation of soil properties, and in particular the soil moisture content. Since the mapping in detail of this soil property for precision viticulture applications is highly costly, the objective of the present research is to analyse its relationship with the normalised difference vegetation index from high resolution satellite images to the use it in the definition of vineyard zonal management. The final aim is to improve irrigation in commercial vineyard blocks for better management of inputs and to deliver a more homogeneous fruit to the winery. The study was carried out in a vineyard block located in Raimat (NE Spain, Costers del Segre Designation of Origin). This is a semi-arid area with continental Mediterranean climate and a total annual precipitation between 300-400 mm. The vineyard block (4.5 ha) is planted with Syrah vines in a 3x2 m pattern. The vines are irrigated by means of drips under a partial root drying schedule. Initially, the irrigation sectors had a quadrangular distribution, with a size of about 1 ha each. Yield is highly variable within the block, presenting a coefficient of variation of 24.9%. For the measurement of the soil moisture content a regular sampling grid of 30 x 40 m was defined. This represents a sample density of 8 samples ha-1. At the nodes of the grid, TDR (Time Domain Reflectometer) probe tubes were permanently installed up to the 80 cm or up to reaching a contrasting layer. Multi-temporal measures were taken at different depths (each 20 cm) between November 2006 and December 2007. For each date, a map of the variability of the profile soil moisture content was interpolated by means of geostatistical analysis: from the measured values at the grid points the experimental variograms were computed and modelled and global block kriging (10 m squared blocks) undertaken with a grid spacing of 3 m x 3 m. On the other hand, three Quickbird-2 satellite images where acquired and processed to monitor plant vigour. The dates of images acquisition were: 29-07-2004, 13-07-2005 and 13-07-2006. They are within the range of

Estimates of deep percolation beneath native vegetation, irrigated fields, and the Amargosa-River Channel, Amargosa Desert, Nye County, Nevada

USGS Publications Warehouse

Stonestrom, David A.; Prudic, David E.; Laczniak, Randell J.; Akstin, Katherine C.; Boyd, Robert A.; Henkelman, Katherine K.

2003-01-01

The presence and approximate rates of deep percolation beneath areas of native vegetation, irrigated fields, and the Amargosa-River channel in the Amargosa Desert of southern Nevada were evaluated using the chloride mass-balance method and inferred downward velocities of chloride and nitrate peaks. Estimates of deep-percolation rates in the Amargosa Desert are needed for the analysis of regional ground-water flow and transport. An understanding of regional flow patterns is important because ground water originating on the Nevada Test Site may pass through the area before discharging from springs at lower elevations in the Amargosa Desert and in Death Valley. Nine boreholes 10 to 16 meters deep were cored nearly continuously using a hollow-stem auger designed for gravelly sediments. Two boreholes were drilled in each of three irrigated fields in the Amargosa-Farms area, two in the Amargosa-River channel, and one in an undisturbed area of native vegetation. Data from previously cored boreholes beneath undisturbed, native vegetation were compared with the new data to further assess deep percolation under current climatic conditions and provide information on spatial variability.The profiles beneath native vegetation were characterized by large amounts of accumulated chloride just below the root zone with almost no further accumulation at greater depths. This pattern is typical of profiles beneath interfluvial areas in arid alluvial basins of the southwestern United States, where salts have been accumulating since the end of the Pleistocene. The profiles beneath irrigated fields and the Amargosa-River channel contained more than twice the volume of water compared to profiles beneath native vegetation, consistent with active deep percolation beneath these sites. Chloride profiles beneath two older fields (cultivated since the 1960’s) as well as the upstream Amargosa-River site were indicative of long-term, quasi-steady deep percolation. Chloride profiles beneath the newest field (cultivated since 1993), the downstream Amargosa-River site, and the edge of an older field were indicative of recently active deep percolation moving previously accumulated salts from the upper profile to greater depths.Results clearly indicate that deep percolation and ground-water recharge occur not only beneath areas of irrigation but also beneath ephemeral stream channels, despite the arid climate and infrequency of runoff. Rates of deep percolation beneath irrigated fields ranged from 0.1 to 0.5 m/yr. Estimated rates of deep percolation beneath the Amargosa-River channel ranged from 0.02 to 0.15 m/yr. Only a few decades are needed for excess irrigation water to move through the unsaturated zone and recharge ground water. Assuming vertical, one-dimensional flow, the estimated time for irrigation-return flow to reach the water table beneath the irrigated fields ranged from about 10 to 70 years. In contrast, infiltration from present-day runoff takes centuries to move through the unsaturated zone and reach the water table. The estimated time for water to reach the water table beneath the channel ranged from 140 to 1000 years. These values represent minimum times, as they do not take lateral flow into account. The estimated fraction of irrigation water becoming deep percolation averaged 8 to 16 percent. Similar fractions of infiltration from ephemeral flow events were estimated to become deep percolation beneath the normally dry Amargosa-River channel. In areas where flood-induced channel migration occurs at sub-centennial frequencies, residence times in the unsaturated zone beneath the Amargosa channel could be longer. Estimates of deep percolation presented herein provide a basis for evaluating the importance of recharge from irrigation and channel infiltration in models of ground-water flow from the Nevada Test Site.

The Slow Moving Threat of Groundwater Salinization: Mechanisms, Costs, and Adaptation Strategies

NASA Astrophysics Data System (ADS)

Pauloo, R.; Guo, Z.; Fogg, G. E.

2016-12-01

Population growth, the Green Revolution, and climate uncertainties have accelerated overdraft in groundwater basins worldwide, which in some regions is converting these basins into closed hydrologic systems, where the dominant exits for water are evapotranspiration and pumping. Irrigated agricultural basins are particularly at risk to groundwater salinization, as naturally occurring (i.e., sodium, potassium, chloride) and anthropogenic (i.e., nitrate fertilizers) salts leach back into the water table through the root zone, while a large portion of pumped groundwater leaves the system as it is evapotranspired by crops. Decreasing water quality associated with increases in Total Dissolved Solids (TDS) has been documented in aquifers across the United States in the past half century. This study suggests that the increase in TDS in aquifers can be partially explained by closed basin hydrogeology and rock-water interactions leading to groundwater salinization. This study will present: (1) a report on historical water quality in the Tulare basin, (2) a forward simulation of salt balance in Tulare Basin based on the Department of Water Resources numerical model C2VSim, and a simple mixing model, (3) an economic analysis forecasting the cost of desalination under varying degrees of managed groundwater recharge where the basin is gradually filled, avoiding hydraulic closure.

Growth and Flowering Responses of Cut Chrysanthemum Grown under Restricted Root Volume to Irrigation Frequency

PubMed Central

Taweesak, Viyachai; Lee Abdullah, Thohirah; Hassan, Siti Aishah; Kamarulzaman, Nitty Hirawaty; Wan Yusoff, Wan Abdullah

2014-01-01

Influences of irrigation frequency on the growth and flowering of chrysanthemum grown under restricted root volume were tested. Chrysanthemum cuttings (Chrysanthemum morifolium “Reagan White”) were grown in seedling tray which contained coconut peat in volumes of 73 and 140 cm3. Plants were irrigated with drip irrigation at irrigation frequencies of 4 (266 mL), 6 (400 mL), and 8 (533 mL) times/day to observe their growth and flowering performances. There was interaction between irrigation frequency and substrate volume on plant height of chrysanthemum. Plants grown in 140 cm3 substrates and irrigated 6 times/day produced the tallest plant of 109.25 cm. Plants irrigated 6 and 8 times/day had significantly higher level of phosphorus content in their leaves than those plants irrigated 4 times/day. The total leaf area, number of internodes, leaf length, and leaf width of chrysanthemums grown in 140 cm3 substrate were significantly higher than those grown in 73 cm3 substrate. The numbers of flowers were affected by both irrigation frequencies and substrate volumes. Chrysanthemums irrigated 8 times/day had an average of 19.56 flowers while those irrigated 4 times/day had an average of 16.63 flowers. Increasing irrigation frequency can improve the growth and flowering of chrysanthemums in small substrate volumes. PMID:25478586

Regional Scale Simulations of Nitrate Leaching through Agricultural Soils of California

NASA Astrophysics Data System (ADS)

Diamantopoulos, E.; Walkinshaw, M.; O'Geen, A. T.; Harter, T.

2016-12-01

Nitrate is recognized as one of California's most widespread groundwater contaminants. As opposed to point sources, which are relative easily identifiable sources of contamination, non-point sources of nitrate are diffuse and linked with widespread use of fertilizers in agricultural soils. California's agricultural regions have an incredible diversity of soils that encompass a huge range of properties. This complicates studies dealing with nitrate risk assessment, since important biological and physicochemical processes appear at the first meters of the vadose zone. The objective of this study is to evaluate all agricultural soils in California according to their potentiality for nitrate leaching based on numerical simulations using the Richards equation. We conducted simulations for 6000 unique soil profiles (over 22000 soil horizons) taking into account the effect of climate, crop type, irrigation and fertilization management scenarios. The final goal of this study is to evaluate simple management methods in terms of reduced nitrate leaching. We estimated drainage rates of water under the root zone and nitrate concentrations in the drain water at the regional scale. We present maps for all agricultural soils in California which can be used for risk assessment studies. Finally, our results indicate that adoption of simple irrigation and fertilization methods may significantly reduce nitrate leaching in vulnerable regions.

Field note: irrigation of tree stands with groundwater containing 1,4-dioxane.

PubMed

Ferro, Ari M; Tammi, Carl E

2009-07-01

Coniferous and deciduous tree stands totaling 14 ha were recently planted on a closed landfill, and when mature, the stands are expected to be part of a natural treatment system for recovered groundwater. The trees would be irrigated at the rate of 189 L/min year-round with water containing 1,4-dioxane (< 10 mg/L), a compound that would be taken up and phytovolatilized by the trees. The water is moderately saline and contains elevated levels of manganese. This paper describes a concurrent series of preliminary studies, performed prior to the full-scale planting, to assess the feasibility of the phytoremediation system. Greenhouse experiments were carried out to identify tree species that can take up 1,4-dioxane and are tolerant of the water. Estimates were made of the area of the tree stand necessary to transpire the irrigation water plus precipitation. The landfill matrix was characterized in terms of its percolation rate and water holding capacity and based on those results salinity-modeling studies were carried out to estimate the fate and leaching potential of the various inorganic species that would accumulate in the root-zone of the trees. A pilot study, currently in progress on the landfill, suggested that the landfill cap is a suitable matrix for the establishment of large trees, and that the stands could be irrigated without the production of excess drainage.

Durum wheat seedlings in saline conditions: Salt spray versus root-zone salinity

NASA Astrophysics Data System (ADS)

Spanò, Carmelina; Bottega, Stefania

2016-02-01

Salinity is an increasingly serious problem with a strong negative impact on plant productivity. Though many studies have been made on salt stress induced by high NaCl concentrations in the root-zone, few data concern the response of plants to saline aerosol, one of the main constraints in coastal areas. In order to study more in depth wheat salinity tolerance and to evaluate damage and antioxidant response induced by various modes of salt application, seedlings of Triticum turgidum ssp. durum, cv. Cappelli were treated for 2 and 7 days with salt in the root-zone (0, 50 and 200 mM NaCl) or with salt spray (400 mM NaCl + 0 or 200 mM NaCl in the root-zone). Seedlings accumulated Na+ in their leaves and therefore part of their ability to tolerate high salinity seems to be due to Na+ leaf tissue tolerance. Durum wheat, confirmed as a partially tolerant plant, shows a higher damage under airborne salinity, when both an increase in TBA-reactive material (indicative of lipid peroxidation) and a decrease in root growth were recorded. A different antioxidant response was activated, depending on the type of salt supply. Salt treatment induced a depletion of the reducing power of both ascorbate and glutathione while the highest contents of proline were detected under salt spray conditions. In the short term catalase and ascorbate peroxidase co-operated with glutathione peroxidase in the scavenging of hydrogen peroxide, in particular in salt spray-treated plants. From our data, the durum wheat cultivar Cappelli seems to be sensitive to airborne salinity.

Laser assisted irrigation and hand irrigation for root canal decontamination: a comparison

NASA Astrophysics Data System (ADS)

Olivi, M.; Stefanucci, M.; Todea, C.

2014-01-01

Aim: to compare the bactericidal efficiency of conventional method and LAI for root canal decontamination. Material and method: 22 human single root teeth, extracted for periodontal problems, mechanically prepared up to ISO 25 at the working lenght were divided in 2 groups: after sterilization, the teeth were infected with enterococcus faecalis and incubated for 4 weeks. Group A: 10 teeth were irrigated with conventional hand technique (CI): 3ml of 5% NaClO were used for two times of 30s each and after washing with sterile bi-distilled water for 20s, a final irrigation was performed with 3ml of 17% EDTA. Group B: 10 teeth were irrigated with 3ml of NaClO and activated by erbium laser, two cycles of 30s; also the final irrigation with 3ml of 17% EDTA was activated by erbium laser. In both the groups a resting time of 30s was used between the two sessions to allow the reaction rate of NaClO. The Erbium laser 2940 nm (LightWalker AT, Fotona; Lublijana, Slovenia) was used with 50microsecond pulse duration, at 15Hz, 20mJ, with a 600micron PIPS tip. Two samples were used as positive and negative control.

Antibacterial Efficacy of a New Sonic Irrigation Device for Root Canal Disinfection.

PubMed

Neuhaus, Klaus W; Liebi, Melanie; Stauffacher, Simone; Eick, Sigrun; Lussi, Adrian

2016-12-01

Passive ultrasonic irrigation (PUI) is the most widespread method used to activate irrigation solutions. Concerns have been raised that PUI is less effective in curved root canals and is not passive at all. Our aim was to compare a novel passive sonic irrigation (PSI) device (6000 Hz) with PUI and manual irrigation (MI) with respect to their efficiency in removing different endodontic microorganisms from curved and straight root canals. We performed 2 experiments as follows. In a 3-day infection model, we included 8 groups of single or dual microbial species that were rinsed with 0.9% sodium chloride using PSI, PUI, or MI. Colony-forming units (CFUs) were counted after incubation, and log 10 transformations were performed for statistical comparisons. In a 21-d infection model, we tested the same irrigation protocols on 4 groups of microorganisms and used 1.5% sodium hypochlorite as an irrigant. Infection control samples were taken at day 0, 3, 5, and 7 after treatment and were subsequently reincubated. Using sodium chloride as an irrigant, the amount of reduction in CFUs compared with the negative control was approximately 3 log 10 units for PSI at 6000 Hz, 2 log 10 units for PUI, and 1 log 10 unit for MI. PSI reduced the microorganism CFUs significantly better than PUI. Using sodium hypochlorite led to a significant reduction in microorganism CFUs even with MI. After 3 days, compared with MI, microorganism regrowth significantly reduced after PSI and PUI treatment, but in these groups, in at least half of the samples, microorganisms were detectable after 7 days. PSI at 6000 Hz might be at least equal to PUI with respect to reduction of the microbial load in curved and straight root canals. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Simulation of Soil Wetting Patterns in Drip and Subsurface Irrigation. Effects in Design and Irrigation Management Variables.

NASA Astrophysics Data System (ADS)

Rodríguez-Sinobas, L.; Gil-Rodríguez, M.; Sánchez, R.; Losada, A.; Castañón, G.; Juana, L.; Laguna, F. V.; Benítez, J.

2010-05-01

Conventional drip irrigation is considered one of the most efficient irrigation systems. Alternatively to traditional surface drip irrigation systems (DI), laterals are deployed underneath the soil surface, as in subsurface drip irrigation (SDI), leading to a higher potential efficiency, which is of especial interest in places where water is a limited source. The design and management of DI and SDI systems involve selection of an appropriate combination of emitter discharge rate and spacing between emitters and the inlet pressure and irrigation time for any given set of soil, crop, and climatic conditions, as well as understanding the wetted zone pattern around the emitter. Likewise, water distribution is affected by soil hydraulic properties, initial water content, emitter discharge, irrigation frequency, evapotranspiration and root characteristics. However, complexity arousing of soil water properties and soil profile characteristics means that these are often not properly considered in the design and management of those systems. A better understanding of the infiltration process around the discharge point source should contribute to increase water use efficiency and thus to reduce the risk of environmental impact of irrigation. In this regard, numerical models have been proved to be a powerful tool to analyze the evolution of the wetting pattern during the distribution and redistribution processes, in order to explore irrigation management strategies, to set up the duration of irrigation, and finally to optimize water use efficiency. Also, irrigation design variables such as emitter spacing and discharge could also be assessed. In this study the suitability of the HYDRUS-2D to simulate infiltration process around an emitter during irrigation of a loamy soil with drip and SDI laterals has been addressed. The model was then applied in order to evaluate the main dimensions of the wetted soil volume surrounding the emitter during irrigation. Irrigation uniformity with DI and SDI laterals were determined by field evaluations at different inlet head pressures. Results were related with estimations made on water distribution within the soil that were simulated taking into account the emitter discharge at different lateral locations, initial soil water content, soil hydraulic properties and time of irrigation. Conclusions highlight the effect of emitter discharge, emitter spacing, and irrigation time on wetting patterns, and thus solute transport, in both drip and subsurface drip irrigation. The effect of emitter depth was also considered in SDI. Some recommendations for the design and management of these irrigation systems are also provided.

Quasi 3D modeling of water flow and solute transport in vadose zone and groundwater

NASA Astrophysics Data System (ADS)

Yakirevich, A.; Kuznetsov, M.; Weisbrod, N.; Pachepsky, Y. A.

2013-12-01

The complexity of subsurface flow systems calls for a variety of concepts leading to the multiplicity of simplified flow models. One commonly used simplification is based on the assumption that lateral flow and transport in unsaturated zone is insignificant unless the capillary fringe is involved. In such cases the flow and transport in the unsaturated zone above groundwater level can be simulated as a 1D phenomenon, whereas through groundwater they are viewed as 2D or 3D phenomena. A new approach for a numerical scheme for 3D variably saturated flow and transport is presented. A Quasi-3D approach allows representing flow in the 'vadose zone - aquifer' system by a series of 1D Richards' equations solved in variably-saturated zone and by 3D-saturated flow equation in groundwater (modified MODFLOW code). The 1D and 3D equations are coupled at the phreatic surface in a way that aquifer replenishment is calculated using the Richards' equation, and solving for the moving water table does not require definition of the specific yield parameter. The 3D advection-dispersion equation is solved in the entire domain by the MT3D code. Using implicit finite differences approximation to couple processes in the vadose zone and groundwater provides mass conservation and increase of computational efficiency. The above model was applied to simulate the impact of irrigation on groundwater salinity in the Alto Piura aquifer (Northern Peru). Studies on changing groundwater quality in arid and semi-arid lands show that irrigation return flow is one of the major factors contributing to aquifer salinization. Existing mathematical models do not account explicitly for the solute recycling during irrigation on a daily scale. Recycling occurs throughout the unsaturated and saturated zones, as function of the solute mass extracted from pumping wells. Salt concentration in irrigation water is calculated at each time step as a function of concentration of both surface water and groundwater extracted at specific locations. Three scenarios were considered: (i) use of furrow irrigation and groundwater extraction (the present situation); (ii) increase of groundwater pumping by 50% compared to the first scenario; and (iii) transition from furrow irrigation to drip irrigation, thus decreasing irrigation volume by around 60% compared to the first scenario. Results indicate that in different irrigation areas, the simulated increase rates of total dissolved solids in groundwater vary from 3 to17 mg/L/ year, depending on hydrogeological and hydrochemical conditions, volumes of water extracted, and proportion between surface water and groundwater applied. The transition from furrow irrigation to drip irrigation can decrease the negative impact of return flow on groundwater quality; however drip irrigation causes faster simulated soil salinization compared to furrow irrigation. The quasi 3D modeling appeared to be efficient in elucidating solute recycling effects on soil and groundwater salinity.

Efficacy of xylene and passive ultrasonic irrigation on remaining root filling material during retreatment of anatomically complex teeth.

PubMed

Cavenago, B C; Ordinola-Zapata, R; Duarte, M A H; del Carpio-Perochena, A E; Villas-Bôas, M H; Marciano, M A; Bramante, C M; Moraes, I G

2014-11-01

To evaluate the volume of remaining filling material in the mesial root canals of mandibular molars after root canal retreatment with different procedures performed sequentially. The mesial root canals of 12 human first mandibular molars were instrumented using the BioRace system until a size 25, .06 taper instrument. The mesial roots were filled with gutta-percha and AH-Plus using a vertical compaction technique. The specimens were scanned using microcomputed tomography with a voxel size of 16.8 μm before and after the retreatment procedures. To remove the filling material, the root canals were enlarged until the size 40, .04 taper instrument. The second step was to irrigate the root canals with xylene in the attempt to clean the root canals with paper points. In the third step, the passive ultrasonic irrigation technique (PUI) was performed using 2.5% sodium hypochlorite. The initial and residual filling material volume (mm(3) ) after each step was evaluated from the 0.5 to 6.5 mm level. The obtained data were expressed in terms of percentage of residual filling material. Statistical analysis was performed using the Friedman test (P < 0.05). All specimens had residual filling materials after all retreatment procedures. Passive ultrasonic irrigation enhanced the elimination of residual filling material in comparison with the mechanical stage at the 0.5-2.5 mm and 4.5-6.5 mm levels (P < 0.05). No significant difference was found between xylene and PUI methods. Filling materials were not completely removed by any of the retreatment procedures. The use of xylene and PUI after mechanical instrumentation enhanced removal of materials during endodontic retreatment of anatomically complex teeth. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

A comparison of groundwater recharge estimation methods in a semi-arid, coastal avocado and citrus orchard (Ventura County, California)

NASA Astrophysics Data System (ADS)

Grismer, Mark E.; Bachman, S.; Powers, T.

2000-10-01

We assess the relative merits of application of the most commonly used field methods (soil-water balance (SWB), chloride mass balance (CMB) and soil moisture monitoring (NP)) to determine recharge rates in micro-irrigated and non-irrigated areas of a semi-arid coastal orchard located in a relatively complex geological environment.Application of the CMB method to estimate recharge rates was difficult owing to the unusually high, variable soil-water chloride concentrations. In addition, contrary to that expected, the chloride concentration distribution at depths below the root zone in the non-irrigated soil profiles was greater than that in the irrigated profiles. The CMB method severely underestimated recharge rates in the non-irrigated areas when compared with the other methods, although the CMB method estimated recharge rates for the irrigated areas, that were similar to those from the other methods, ranging from 42 to 141 mm/year.The SWB method, constructed for a 15-year period, provided insight into the recharge process being driven by winter rains rather than summer irrigation and indicated an average rate of 75 mm/year and 164 mm/year for the 1984 - 98 and 1996 - 98 periods, respectively. Assuming similar soil-water holding capacity, these recharge rates applied to both irrigated and non-irrigated areas. Use of the long period of record was important because it encompassed both drought and heavy rainfall years. Successful application of the SWB method, however, required considerable additional field measurements of orchard ETc, soil-water holding capacity and estimation of rainfall interception - runoff losses.Continuous soil moisture monitoring (NP) was necessary to identify both daily and seasonal seepage processes to corroborate the other recharge estimates. Measured recharge rates during the 1996 - 1998 period in both the orchards and non-irrigated site averaged 180 mm/year. The pattern of soil profile drying during the summer irrigation season, followed by progressive wetting during the winter rainy season was observed in both irrigated and non-irrigated soil profiles, confirming that groundwater recharge was rainfall driven and that micro-irrigation did not predispose the soil profile to excess rainfall recharge. The ability to make this recharge assessment, however, depended on making multiple field measurements associated with all three methods, suggesting that any one should not be used alone.

Evaluation of an operational real-time irrigation scheduling scheme for drip irrigated citrus fields in Picassent, Spain

NASA Astrophysics Data System (ADS)

Li, Dazhi; Hendricks-Franssen, Harrie-Jan; Han, Xujun; Jiménez Bello, Miguel Angel; Martínez Alzamora, Fernando; Vereecken, Harry

2017-04-01

Irrigated agriculture accounts worldwide for 40% of food production and 70% of fresh water withdrawals. Irrigation scheduling aims to minimize water use while maintaining the agricultural production. In this study we were concerned with the real-time automatic control of irrigation, which calculates daily water allocation by combining information from soil moisture sensors and a land surface model. The combination of soil moisture measurements and predictions by the Community Land Model (CLM) using sequential data assimilation (DA) is a promising alternative to improve the estimate of soil and plant water status. The LETKF (Local Ensemble Transform Kalman Filter) was chosen to assimilate soil water content measured by FDR (Frequency Domain Reflectometry) into CLM and improve the initial (soil moisture) conditions for the next model run. In addition, predictions by the GFS (Global Forecast System) atmospheric simulation model were used as atmospheric input data for CLM to predict an ensemble of possible soil moisture evolutions for the next days. The difference between predicted and target soil water content is defined as the water deficit, and the irrigation amount was calculated by the integrated water deficit over the root zone. The corresponding irrigation time to apply the required water was introduced in SCADA (supervisory control and data acquisition system) for each citrus field. In total 6 fields were irrigated according our optimization approach including data assimilation (CLM-DA) and there were also 2 fields following the FAO (Food and Agriculture Organization) water balance method and 4 fields controlled by farmers as reference. During the real-time irrigation campaign in Valencia from July to October in 2015 and June to October in 2016, the applied irrigation amount, stem water potential and soil moisture content were recorded. The data indicated that 5% 20% less irrigation water was needed for the CLM-DA scheduled fields than for the other fields following the FAO or farmers' method. Stem water potential data indicated that the CLM-DA fields were not suffering from water stress during most of the irrigation period. Even though the CLM-DA fields received the least irrigation water, the orange production was not suppressed either. Our results show the water saving potential of the CLM-DA method compared to other traditional irrigation methods.

A Review Over Benefits and Drawbacks of Combining Sodium Hypochlorite with Other Endodontic Materials

PubMed Central

Mohammadi, Zahed; Shalavi, Sousan; Moeintaghavi, Amir

2017-01-01

Introduction: As the root canal system considered to be complex and unpredictable, using root canal irrigants and medicaments are essential in order to enhance the disinfection of the canal. Sodium hypochlorite is the most common irrigant in endodontics. Despite its excellent antimicrobial activity and tissue solubility, sodium hypochlorite lacks some important properties such as substantivity and smear layer removing ability. Objective: The aim of this review was to address benefits and drawbacks of combining sodium hypochlorite with other root canal irrigants and medicaments. Discussion: According to the reviewed articles, NaOCl is the most common irrigation solution in endodontics. However, it has some drawbacks such as inability to remove smear layer. One of the drawbacks of NaOCl is its inability to remove the smear layer and lack of substantivity. Conclusion: The adjunctive use of other materials has been suggested to improve NaOCl efficacy. Nevertheless, further studies are required in this field. PMID:29387282

Biofilm removal by 6% sodium hypochlorite activated by different irrigation techniques.

PubMed

Ordinola-Zapata, R; Bramante, C M; Aprecio, R M; Handysides, R; Jaramillo, D E

2014-07-01

To compare the removal of biofilm utilizing four irrigation techniques on a bovine root canal model. Fifty dentine specimens (2 × 2 mm) were infected with biofilm. The samples were then adapted to previously created cavities in the bovine model. The root canals were irrigated twice with 2 mL of 6% sodium hypochlorite for 2 min (4 min total). Following initial irrigation, the different treatment modalities were introduced for 60 s (3 × 20 s intervals). The evaluated techniques were needle irrigation, Endoactivator (Dentsply Tulsa Dental, Tulsa, OK, USA), passive ultrasonic irrigation and laser-activated irrigation (photon-induced photoacoustic streaming). The controls were irrigated with distilled water and conventional needle irrigation. Subsequently, the dentine samples were separated from the model and analysed using a scanning electron microscope (SEM). Fifteen operative fields were scanned per block, and SEM pictures were captured. Two calibrated evaluators examined the images and collected data using a four-degree scale. Nonparametric tests were used to evaluate for statistical significance amongst the groups. The group undergoing laser-activated irrigation using photon-induced photoacoustic streaming exhibited the most favourable results in the removal of biofilm. Passive ultrasonic irrigation scores were significantly lower than both the Endoactivator and needle irrigation scores. Sonic and needle irrigation were not significantly different. The least favourable results were found in the control group. Laser activation of 6% sodium hypochlorite significantly improved the cleaning of biofilm-infected dentine followed by passive ultrasonic irrigation. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

An evaluation of microbial leakage after using MTAD as a final irrigation.

PubMed

Ghoddusi, Jamileh; Rohani, Armita; Rashed, Tahereh; Ghaziani, Pari; Akbari, Majid

2007-02-01

Cleaning the root canal is not possible without using proper irrigation. The aim of this in vitro study was to evaluate the effect of MTAD as a final irrigant on bacterial leakage of the root canal, and its interaction with two conventional root canal sealers. We used 132 extracted human maxillary anterior teeth. The teeth were randomly divided into three experimental groups (n=40) and two groups (n=6) of positive and negative control. In group 1, the smear layer was not removed and irrigation was performed using 5.25% NaOCl. In group 2, the smear layer was removed using EDTA, and in group 3, the smear layer was removed using MTAD according to the clinical protocol of use. The teeth in each group were obturated with gutta-percha and AH-Plus or Rickert sealer. The coronal portion of each root was placed in contact with inoculum of Streptococcus mutans in Brain Heart Infusion (BHI) culture media. Each root tip was placed in one bottle containing sterile BHI. Mean duration of bacterial penetration in groups 2 and 3 was significantly greater than in group 1, but there was no significant difference between groups 2 and 3. According to our findings, it takes longer for bacteria to penetrate when either EDTA or MTAD is used for smear layer removal. The root canals obturated with AH Plus showed significantly longer duration of resistance to bacterial penetration than canals obturated with Rickert.

Experimental monitoring and numerical study of pesticide (carbofuran) transfer in an agricultural soil at a field site

NASA Astrophysics Data System (ADS)

Hmimou, Abderrahim; Maslouhi, Abdellatif; Tamoh, Karim; Candela, Lucila

2014-09-01

We studied the transport of a pesticide at field scale, namely carbofuran molecule, which is known for its high mobility, especially in sandy soils with high hydraulic conductivity and low organic matter. To add to our knowledge of the future of this high-mobility molecule in this type of soils, we developed a mechanistic numerical model allowing the simulation of hydric and solute transfers (bromide and carbofuran) in the soil. We carried out this study in an agricultural plot in the region of Mnasra in Morocco. Confrontation of the measured and simulated values allowed the calibration of the parameters of hydric transfer and carbofuran. The developed model accurately reproduces the measured values. Despite a weak irrigation and precipitation regime, carbofuran was practically leached beyond the root zone. Prospective simulations show that under a more important irrigation regime, carbofuran reaches a 100-cm depth, whereas it does not exceed 60 cm under a deficit regime.

Statistical Analysis Of Heavy Metals Concentration In Watermelon Plants Irrigated By Wastewater

NASA Astrophysics Data System (ADS)

Khanjani, M. J.; Maghsoudi moud, A. A.; Saffari, V. R.; Hashamipor, S. M.; Soltanizadeh, M.

2008-01-01

Concentration of heavy metals in vegetables irrigated by urban wastewater is a cause of serious concern due to the potentials health problems of consuming contaminated produce. In this study it is tried to model the concentration of heavy metals (Cd, Cr, Cu, Fe,…) as a function of their concentration in watermelon roots and stems. Our study shows there is a good relationship between them for most of collected data. By measuring the concentration in root and stem of watermelon plant samples before harvesting, the concentration of heavy metal in watermelon's fruit can be estimated by presented mathematical models. This study shows the concentrations of heavy metals in fruits, roots and stems of watermelon plants are very high and in dangerous level when irrigated by municipal waste water.

Management of Chronic Periodontitis Using Subgingival Irrigation of Ozonized Water: A Clinical and Microbiological Study.

PubMed

Issac, Annie V; Mathew, Jayan Jacob; Ambooken, Majo; Kachappilly, Arun Jose; Pk, Ajithkumar; Johny, Thomas; Vk, Linith; Samuel, Anju

2015-08-01

Adjunctive use of professional subgingival irrigation with scaling and root planing (SRP) has been found to be beneficial in eradicating the residual microorganisms in the pocket. To evaluate the effect of ozonized water subgingival irrigation on microbiologic parameters and clinical parameters namely Gingival index, probing pocket depth, and clinical attachment level. Thirty chronic periodontitis patients with probing pocket depth ≥6mm on at least one tooth on contra lateral sides of opposite arches were included in the study. The test sites were subjected to ozonized water subgingival irrigation with subgingival irrigation device fitted with a modified subgingival tip. Control sites were subjected to scaling and root planing only. The following clinical parameters were recorded initially and after 4 weeks at the test sites and control sites. Plaque Index, Gingival Index, probing pocket depth, clinical attachment level. Microbiologic sampling was done for the test at the baseline, after scaling, immediately after ozonized water subgingival irrigation and after 4 weeks. In control sites microbiologic sampling was done at the baseline, after scaling and after 4 weeks. The following observations were made after 4 weeks. The results were statistically analysed using independent t-test and paired t-test. Test sites showed a greater reduction in pocket depth and gain in clinical attachment compared to control sites. The total anaerobic counts were significantly reduced by ozonized water subgingival irrigation along with SRP compared to SRP alone. Ozonized water subgingival irrigation can improve the clinical and microbiological parameters in patients with chronic periodontitis when used as an adjunct to scaling and root planing.

Irrigation and Nitrogen Regimes Promote the Use of Soil Water and Nitrate Nitrogen from Deep Soil Layers by Regulating Root Growth in Wheat.

PubMed

Liu, Weixing; Ma, Geng; Wang, Chenyang; Wang, Jiarui; Lu, Hongfang; Li, Shasha; Feng, Wei; Xie, Yingxin; Ma, Dongyun; Kang, Guozhang

2018-01-01

Unreasonably high irrigation levels and excessive nitrogen (N) supplementation are common occurrences in the North China Plain that affect winter wheat production. Therefore, a 6-yr-long stationary field experiment was conducted to investigate the effects of irrigation and N regimes on root development and their relationship with soil water and N use in different soil layers. Compared to the non-irrigated treatment (W0), a single irrigation at jointing (W1) significantly increased yield by 3.6-45.6%. With increases in water (W2, a second irrigation at flowering), grain yield was significantly improved by 14.1-45.3% compared to the W1 treatments during the drier growing seasons (2010-2011, 2012-2013, and 2015-2016). However, under sufficient pre-sowing soil moisture conditions, grain yield was not increased, and water use efficiency (WUE) decreased significantly in the W2 treatments during normal precipitation seasons (2011-2012, 2013-2014, and 2014-2015). Irrigating the soil twice inhibited root growth into the deeper soil depth profiles and thus weakened the utilization of soil water and NO 3 -N from the deep soil layers. N applications increased yield by 19.1-64.5%, with a corresponding increase in WUE of 66.9-83.9% compared to the no-N treatment (N0). However, there was no further increase in grain yield and the WUE response when N rates exceeded 240 and 180 kg N ha -1 , respectively. A N application rate of 240 kg ha -1 facilitated root growth in the deep soil layers, which was conducive to utilization of soil water and NO 3 -N and also in reducing the residual NO 3 -N. Correlation analysis indicated that the grain yield was significantly positively correlated with soil water storage (SWS) and nitrate nitrogen accumulation (SNA) prior to sowing. Therefore, N rates of 180-240 kg ha -1 with two irrigations can reduce the risk of yield loss that occurs due to reduced precipitation during the wheat growing seasons, while under better soil moisture conditions, a single irrigation at jointing was effective and more economical.

Alkaline Sodium Hypochlorite Irrigant and Its Chemical Interactions

PubMed Central

Kahler, Bill; Walsh, Laurence J.

2017-01-01

Endodontic irrigating solutions may interact chemically with one another. This is important, because even when solutions are not admixed, they will come into contact with one another during an alternating irrigation technique, forming unwanted by-products, which may be toxic or irritant. Mixing or alternating irrigants can also reduce their ability to clean and disinfect the root canal system of teeth by changing their chemical structure with subsequent loss of the active agent, or by inducing precipitate formation in the root canal system. Precipitates occlude dental tubules, resulting in less penetration of antimicrobials and a loss of disinfection efficacy. Sodium hypochlorite is not only a very reactive oxidizing agent, but is also the most commonly used endodontic irrigant. As such, many interactions occurring between it and other irrigants, chelators and other antimicrobials, may occur. Of particular interest is the interaction between sodium hypochlorite and the chelators EDTA, citric acid and etidronate and between sodium hypochlorite and the antimicrobials chlorhexidine, alexidine, MTAD and octenisept. PMID:28961175

[Influence of arbuscular mycorrhizal inoculation on growth and phoxim residue of carrot (Daucus carota L.)].

PubMed

Wang, Fa-Yuan; Chen, Xin; Sun, Xian-Ming; Shi, Zhao-Yong

2010-12-01

A pot culture experiment was carried out to study the influence of arbuscular mycorrhizal (AM) fungi on the growth and phoxim residue of carrot (Daucus carota L). Four levels of phoxim (0, 200, 400, 800 mg x L(-1)) and two AM fungal inocula, Glomus intraradices BEG 141(141), Glomus mosseae BEG 167 (167),and one nonmycorrhizal inoculum (CK), were applied to the sterilized soil. The plants were harvested after 5 months of growth and phoxim was irrigated into the root zone 14 d before plant harvest. Although decreasing with the increase of phoxim dosage, root infection rates of all the mycorrhizal plants were higher than 70%. Phoxim showed no significant dose effect on shoot wet weights and root yields, which were all increased by AM inoculation at four phoxim dosages. Phoxim residues in shoots and roots increased with the increase of phoxim dosage, but decreased by AM inoculation. In general, Glomus intraradices BEG 141 showed more pronounced effects on the growth and phoxim residue of carrot than Glomus mosseae BEG 167 did. Our results show a promising potential of AM fungi in carrot production and controlling pesticide residues.

Anatomy of Sodium Hypochlorite Accidents Involving Facial Ecchymosis – A Review

PubMed Central

Zhu, Wan-chun; Gyamfi, Jacqueline; Niu, Li-na; Schoeffel, G. John; Liu, Si-ying; Santarcangelo, Filippo; Khan, Sara; Tay, Kelvin C-Y.; Pashley, David H.; Tay, Franklin R.

2013-01-01

Objectives Root canal treatment forms an essential part of general dental practice. Sodium hypochlorite (NaOCl) is the most commonly used irrigant in endodontics due to its ability to dissolve organic soft tissues in the root canal system and its action as a potent antimicrobial agent. Although NaOCl accidents created by extrusion of the irrigant through root apices are relatively rare and are seldom life-threatening, they do create substantial morbidity when they occur. Methods To date, NaOCl accidents have only been published as isolated case reports. Although previous studies have attempted to summarise the symptoms involved in these case reports, there was no endeavor to analyse the distribution of soft tissue distribution in those reports. In this review, the anatomy of a classical NaOCl accident that involves facial swelling and ecchymosis is discussed. Results By summarising the facial manifestations presented in previous case reports, a novel hypothesis that involves intravenous infusion of extruded NaOCl into the facial vein via non-collapsible venous sinusoids within the cancellous bone is presented. Conclusions Understanding the mechanism involved in precipitating a classic NaOCl accident will enable the profession to make the best decision regarding the choice of irrigant delivery techniques in root canal débridement, and for manufacturers to design and improve their irrigation systems to achieve maximum safety and efficient cleanliness of the root canal system. PMID:23994710

Anatomy of sodium hypochlorite accidents involving facial ecchymosis - a review.

PubMed

Zhu, Wan-chun; Gyamfi, Jacqueline; Niu, Li-na; Schoeffel, G John; Liu, Si-ying; Santarcangelo, Filippo; Khan, Sara; Tay, Kelvin C-Y; Pashley, David H; Tay, Franklin R

2013-11-01

Root canal treatment forms an essential part of general dental practice. Sodium hypochlorite (NaOCl) is the most commonly used irrigant in endodontics due to its ability to dissolve organic soft tissues in the root canal system and its action as a potent antimicrobial agent. Although NaOCl accidents created by extrusion of the irrigant through root apices are relatively rare and are seldom life-threatening, they do create substantial morbidity when they occur. To date, NaOCl accidents have only been published as isolated case reports. Although previous studies have attempted to summarise the symptoms involved in these case reports, there was no endeavour to analyse the distribution of soft tissue distribution in those reports. In this review, the anatomy of a classical NaOCl accident that involves facial swelling and ecchymosis is discussed. By summarising the facial manifestations presented in previous case reports, a novel hypothesis that involves intravenous infusion of extruded NaOCl into the facial vein via non-collapsible venous sinusoids within the cancellous bone is presented. Understanding the mechanism involved in precipitating a classic NaOCl accident will enable the profession to make the best decision regarding the choice of irrigant delivery techniques in root canal débridement, and for manufacturers to design and improve their irrigation systems to achieve maximum safety and efficient cleanliness of the root canal system. Copyright © 2013 Elsevier Ltd. All rights reserved.

Using Hydrus 2-D to assess the emitters optimal position for Eggplants under surface and subsurface drip irrigation

NASA Astrophysics Data System (ADS)

Ghazouani, Hiba; Autovino, Dario; Douh, Boutheina; Boujelben, Abdel Hamid; Provenznao, Giuseppe; Rallo, Giovanni

2014-05-01

The main objective of the work is to assess the emitters optimal position for Eggplant crop (Solanum melongena L.) in a sandy loam soil irrigated with surface or subsurface drip irrigation systems, by means of field measurements and simulations carried out with Hydrus-2D model. Initially, the performance of the model is evaluated on the basis of the comparison between simulated soil water contents (SWC) and the corresponding measured in two plots, in which laterals with coextruded emitters are laid on the soil surface (T0) and at 20 cm depth (T20), respectively. In order to choose the best position of the lateral, the results of different simulation runs, carried out by changing the installation depth of the lateral (5 cm, 15 cm and 45 cm) were compared in terms of ratio between actual transpiration and total amount of water provided during the entire growing season (WUE). Experiments were carried out, from April to June 2007, at Institut Supérieur Agronomique de Chott Mériem (Sousse, Tunisia). In the two plots, plants were spaced 0.40 m along the row and 1.2 m between the rows. Each plot was irrigated by means of laterals with coextruded emitters spaced 0.40 m and discharging a flow rate equal to 4.0 l h-1 at a nominal pressure of 100 kPa. In each plot, spatial and temporal variability of SWCs were acquired with a Time Domain Reflectometry probe (Trime-FM3), on a total of four 70 cm long access tubes, installed along the direction perpendicular to the plant row, at distances of 0, 20, 40 and 60 cm from the emitter. Irrigation water was supplied, accounting for the rainfall, every 7-10 days at the beginning of the crop cycle (March-April) and approximately once a week during the following stages till the harvesting (May-June), for a total of 15 one-hour watering. To run the model, soil evaporation, Ep, and crop transpiration, Tp were determined according to the modified FAO Penman-Monteith equation and the dual crop coefficient approach, whereas soil hydraulics and rooting system parameters were experimentally determined. Simulated SWCs resulted fairly close to the corresponding measured at different distances from the emitter and therefore the model was able to predict SWCs in the root zone with values of the Root Mean Square Error generally lower than 4%. This result is consequent to the appropriate schematization of the root distribution, as well as of the root water uptake. Simulations also evidenced the contribute of soil evaporation losses when laterals are installed from the soil surface to a 20 cm depth, whereas significant water losses by deep percolation occured at the highest installation depth. The values of WUE associated to the different examined installation depths tend to a very slight increase when the position of the lateral rises from 0 to 15 cm and start to decrease for the higher depths.

When should irrigators invest in more water-efficient technologies as an adaptation to climate change?

NASA Astrophysics Data System (ADS)

Malek, K.; Adam, J. C.; Stockle, C.; Brady, M.; Yoder, J.

2015-12-01

The western US is expected to experience more frequent droughts with higher magnitudes and persistence due to the climate change, with potentially large impacts on agricultural productivity and the economy. Irrigated farmers have many options for minimizing drought impacts including changing crops, engaging in water markets, and switching irrigation technologies. Switching to more efficient irrigation technologies, which increase water availability in the crop root zone through reduction of irrigation losses, receives significant attention because of the promise of maintaining current production with less. However, more efficient irrigation systems are almost always more capital-intensive adaptation strategy particularly compared to changing crops or trading water. A farmer's decision to switch will depend on how much money they project to save from reducing drought damages. The objective of this study is to explore when (and under what climate change scenarios) it makes sense economically for farmers to invest in a new irrigation system. This study was performed over the Yakima River Basin (YRB) in Washington State, although the tools and information gained from this study are transferable to other watersheds in the western US. We used VIC-CropSyst, a large-scale grid-based modeling framework that simulates hydrological processes while mechanistically capturing crop water use, growth and development. The water flows simulated by VIC-CropSyst were used to run the RiverWare river system and water management model (YAK-RW), which simulates river processes and calculates regional water availability for agricultural use each day (i.e., the prorationing ratio). An automated computational platform has been developed and programed to perform the economic analysis for each grid cell, crop types and future climate projections separately, which allows us to explore whether or not implementing a new irrigation system is economically viable. Results of this study indicate that climate change could justify the investment in new irrigation systems during this century, but the timing of a farmer's response is likely to depend on a variety of factors, including changes in the frequency and magnitude of drought events, current irrigation systems, climatological characteristics within the basin, and crop type.

Effects of alternate drip irrigation and superabsorbent polymers on growth and water use of young coffee tree.

PubMed

Liu, Xiaogang; Li, Fusheng; Yang, Qiliang; Wang, Xinle

2016-07-01

To obtain optimal irrigation management for young coffee tree, the effects of alternate drip irrigation (ADI) and superabsorbent polymers on physiology, growth, dry mass accumulation and water use on one-year old Coffea arabica L. tree were investigated. This experiment had three drip irrigation methods, i.e., conventional drip irrigation (CDI), alternate drip irrigation (ADI) and fixed drip irrigation (FDI), and two levels of superabsorbent polymers, i.e., no superabsorbent polymers (NSAP) and added superabsorbent polymers (SAP). Compared to CDI, ADI saved irrigation water by 32.1% and increased water use efficiency (WUE) by 29.9%. SAP increased root-shoot ratio, total dry mass and WUE by 20.3, 24.9 and 33.0%, respectively, when compared to NSAP. Compared to CDI with NSAP treatment, ADI with SAP treatment increased total dry mass by 13.8% and saved irrigation water by 34.4%, thus increased WUE by 73.4%, and it increased root activity, the contents of chlorophyll and soluble sugar in leaves by 162.4, 38.0 and 8.5%, but reduced the contents of proline and malondialdehyde in leaves by 7.2 and 9.7%, respectively. Thus, alternate drip irrigation with superabsorbent polymers increased the growth and WUE of young Coffea arabica L. tree and was optimal irrigation management for young coffee tree.

Semiconductor laser irradiation improves root canal sealing during routine root canal therapy

PubMed Central

Hu, Xingxue; Wang, Dashan; Cui, Ting; Yao, Ruyong

2017-01-01

Objective To evaluate the effect of semiconductor laser irradiation on root canal sealing after routine root canal therapy (RCT). Methods Sixty freshly extracted single-rooted human teeth were randomly divided into six groups (n = 10). The anatomic crowns were sectioned at the cementoenamel junction and the remaining roots were prepared endodontically with conventional RCT methods. Groups A and B were irradiated with semiconductor laser at 1W for 20 seconds; Groups C and D were ultrasonically rinsed for 60 seconds as positive control groups; Groups E and F without treatment of root canal prior to RCT as negative control groups. Root canal sealing of Groups A, C and E were evaluated by measurements of apical microleakage. The teeth from Groups B, D and F were sectioned, and the micro-structures were examined with scanning electron microscopy (SEM). One way ANOVA and LSD-t test were used for statistical analysis (α = .05). Results The apical sealing of both the laser irradiated group and the ultrasonic irrigated group were significantly different from the control group (p<0.5). There was no significant difference between the laser irradiated group and the ultrasonic irrigated group (p>0.5). SEM observation showed that most of the dentinal tubules in the laser irradiation group melted, narrowed or closed, while most of the dentinal tubules in the ultrasonic irrigation group were filled with tooth paste. Conclusion The application of semiconductor laser prior to root canal obturation increases the apical sealing of the roots treated. PMID:28957407

Root-endophytes improve the ecophysiological performance and production of an agricultural species under drought condition

PubMed Central

Molina-Montenegro, Marco A.; Oses, Rómulo; Torres-Díaz, Cristian; Atala, Cristian; Zurita-Silva, Andrés; Ruiz-Lara, Simón

2016-01-01

Throughout many regions of the world, climate change has limited the availability of water for irrigating crops. Indeed, current models of climate change predict that arid and semi-arid zones will be places where precipitation will drastically decrease. In this context, plant root-associated fungi appear as a new strategy to improve ecophysiological performance and yield of crops under abiotic stress. Thus, use of fungal endophytes from ecosystems currently subjected to severe drought conditions could improve the ecophysiological performance and quantum yield of crops exposed to drought. In this study, we evaluated how the inoculation of fungal endophytes isolated from Antarctic plants can improve the net photosynthesis, water use efficiency and production of fresh biomass in a lettuce cultivar, grown under different water availability regimes. In addition, we assessed if the presence of biochemical mechanisms and gene expression related with environmental tolerance are improved in presence of fungal endophytes. Overall, those individuals with presence of endophytes showed higher net photosynthesis and maintained higher water use efficiency in drought conditions, which was correlated with greater fresh and dry biomass production as well as greater root system development. In addition, presence of fungal endophytes was correlated with a higher proline concentration, lower peroxidation of lipids and up-/down-regulation of ion homeostasis. Our results suggest that presence of fungal endophytes could minimize the negative effect of drought by improving drought tolerance through biochemical mechanisms and improving nutritional status. Thus, root-endophytes might be a successful biotechnological tool to maintain high levels of ecophysiological performance and productivity in zones under drought. PMID:27613875

Fibrin gel improves tissue ingrowth and cell differentiation in human immature premolars implanted in rats.

PubMed

Ruangsawasdi, Nisarat; Zehnder, Matthias; Weber, Franz E

2014-02-01

In pulpless immature human premolars implanted in rodents, this study investigated whether fibrin gel offered advantages over leaving the root canal empty regarding soft tissue ingrowth and cell differentiation. Root canals of extracted human immature premolars (n = 12) were accessed and then irrigated with 5% sodium hypochlorite followed by 17% ethylenediaminetetraacetic acid. Root canals were then either left empty or filled with a fibrin gel (n = 6 each) before being placed subcutaneously on top of the calvarial bone of rats (1 tooth per rat) for 12 weeks. After sacrifice, teeth were histologically assessed. Tissue ingrowth was quantified and compared between groups using the Mann-Whitney U test (P < .05). Cells adhering to the pulp canal wall were immunohistochemically screened for the presence of bone sialoprotein (BSP) and dentin sialoprotein (DSP). More tissue grew into the pulp space when teeth were filled with fibrin gel (P < .05). The presence of fibrin gel affected not only the extent of tissue ingrowth but also tissue morphology and differentiation of cells contacting the dentinal wall. In the fibrin gel group, newly formed tissue was similar to normal pulp, constituted of inner pulp, cell-rich zone, cell-free zone, and an apparent odontoblast layer, which stained positive for BSP and DSP. Newly formed blood vessels were also more abundant compared with the initially empty root canals. Under the conditions of this study, fibrin gel improved cell infiltration and cell-dentin interaction. Both are necessary for pulp tissue regeneration. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Temporal variations in arsenic uptake by rice plants in Bangladesh: the role of iron plaque in paddy fields irrigated with groundwater

PubMed Central

Garnier, J.-M.; Travassac, F.; Lenoble, V.; Rose, J.; Zheng, Y.; Hossain, M.S.; Chowdhury, S. H.; Biswas, A. K.; Ahmed, K.M.; Cheng, Z.; van Geen, A.

2010-01-01

The transfer of arsenic to rice grains is a human health issue of growing relevance in regions of southern Asia where shallow groundwater used for irrigation of paddy fields is elevated in As. In the present study, As and Fe concentrations in soil water and in the roots of rice plants, primarily the Fe plaque surrounding the roots, were monitored during the 4-month growing season at two sites irrigated with groundwater containing ~130 μg/L As and two control sites irrigated with water containing <15 μg/L As. At both sites irrigated with contaminated water, As concentrations in soil water increased from <10 μg/L to >1000 μg/L during the first five weeks of the growth season and then gradually declined to <10 μg/L during the last five weeks. At the two control sites, concentrations of As in soil water never exceeded 40 μg/L. At both contaminated sites, the As content of roots and Fe plaque rose to 1000-1500 mg/kg towards the middle of the growth season. It then declined to ~300 mg/kg towards the end, a level still well above As concentration of ~100 mg/kg in roots and plaque measured throughout the growing season at the two control sites. These time series, combined with simple mass balance considerations, demonstrate that the formation of Fe plaque on the roots of rice plants by micro-aeration significant limits uptake of As by rice plants grown in paddy fields. Large variations in the As and Fe content of plant stems at two of the sites irrigated with contaminated water and one of the control sites were also recorded. The origin of these variations, particularly during the last month of the growth season, need to be better understood because they are likely to influence uptake of As in rice grains. PMID:20576285

Distribution of gases in the unsaturated zone at a low-level radioactive-waste disposal site near Sheffield, Illinois

USGS Publications Warehouse

Striegl, Robert G.

1988-01-01

The unsaturated zone is a medium that provides pneumatic communication for the movement of gases from wastes buried in landfills to the atmosphere, biota, and groundwater. Gases in unsaturated glacial and eolian deposits near a waste-disposal trench at the low-level radioactive-waste disposal site near Sheffield, Bureau County, Illinois, were identified, and the spatial and temporal distributions of the partial pressures of those gases were determined for the period January 1984 through January 1986. Methods for the collection and analyses of the gases are described, as are geologic and hydrologic characteristics of the unsaturated zone that affect gas transport. The identified gases, which are of natural and of waste origin, include nitrogen, oxygen, and argon, carbon dioxide, methane, propane, butane, tritiated water vapor, 14carbon dioxide, and 222 radon. Concentrations of methane and 14carbon dioxide originated at the waste, as shown by partial-pressure gradients of the gases; 14carbon dioxide partial pressures exceeded natural background partial pressures by factors greater than 1 million at some locations. Variations in partial pressures of oxygen and carbon dioxide were seasonal among piezometers because of increased root and soil-microbe respiration during summer. Variations in methane and 14carbon dioxide partial pressures were apparently related to discrete releases from waste sources at unpredictable intervals of time. No greater than background partial pressures for tritiated water vapor or 222 radon were measured. (USGS)

Influence of a passive sonic irrigation system on the elimination of bacteria from root canal systems: a clinical study.

PubMed

Huffaker, S Kirk; Safavi, Kamran; Spangberg, Larz S W; Kaufman, Blythe

2010-08-01

The present investigation evaluated the ability of a new passive sonic irrigation (sonic group) system (EndoActivator) to eliminate cultivable bacteria from root canals in vivo and compared it with that of standard syringe irrigation (control group). Data were obtained by using bacteriologic sampling of root canals treated by endodontic residents. Sampling results from 1 session of treatment were then compared with results obtained after intervisit calcium hydroxide disinfection and a second session of treatment. There was no significant difference in the ability of sonic group and control group to eliminate cultivable bacteria from root canals (P > .05). A second session and intervisit calcium hydroxide disinfection were able to eliminate cultivable bacteria from significantly more teeth than a single session of treatment (P < .05). These in vivo results strengthen the case for a multi-visit approach to the treatment of apical periodontitis. Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Sodium Hypochlorite Irrigation and Its Effect on Bond Strength to Dentin

PubMed Central

Abuhaimed, Tariq S.

2017-01-01

Effective shaping and cleaning of root canals are essential for the success of endodontic treatment. Due to the complex anatomy of root canal spaces, the use of various instrumentation techniques alone is not effective in producing bacteria-free root canal spaces. Irrigation, disinfectants, rinses, and intervisit medications are used in conjunction with the mechanical instrumentation to ensure the success of endodontic treatment. Sodium hypochlorite (NaOCl), a halogenated compound, is routinely used to irrigate the root canal during endodontic treatments. NaOCl has been known for its antibacterial action, proteolytic and dissolution capacity, and debridement properties. NaOCl, however, can alter the composition of dentin and hence its interaction with the adhesive resins used to bond the restorative materials to treated dentin. This review therefore covers in depth the action of NaOCl on dentin-adhesive resin bond strength including both enhancement and reduction, then mechanisms proposed for such action, and finally how the adverse action of NaOCl on dentin can be reversed. PMID:28904947

Sodium Hypochlorite Irrigation and Its Effect on Bond Strength to Dentin.

PubMed

Abuhaimed, Tariq S; Abou Neel, Ensanya A

2017-01-01

Effective shaping and cleaning of root canals are essential for the success of endodontic treatment. Due to the complex anatomy of root canal spaces, the use of various instrumentation techniques alone is not effective in producing bacteria-free root canal spaces. Irrigation, disinfectants, rinses, and intervisit medications are used in conjunction with the mechanical instrumentation to ensure the success of endodontic treatment. Sodium hypochlorite (NaOCl), a halogenated compound, is routinely used to irrigate the root canal during endodontic treatments. NaOCl has been known for its antibacterial action, proteolytic and dissolution capacity, and debridement properties. NaOCl, however, can alter the composition of dentin and hence its interaction with the adhesive resins used to bond the restorative materials to treated dentin. This review therefore covers in depth the action of NaOCl on dentin-adhesive resin bond strength including both enhancement and reduction, then mechanisms proposed for such action, and finally how the adverse action of NaOCl on dentin can be reversed.

Effects of soil water availability on water fluxes in winter wheat

NASA Astrophysics Data System (ADS)

Cai, G.; Vanderborght, J.; Langensiepen, M.; Vereecken, H.

2014-12-01

Quantifying soil water availability in water-limited ecosystems on plant water use continues to be a practical problem in agronomy. Transpiration which represents plant water demand is closely in relation to root water uptake in the root zone and sap flow in plant stems. However, few studies have been concentrated on influences of soil moisture on root water uptake and sap flow in crops. This study was undertaken to investigate (i) whether root water uptake and sap flow correlate with the transpiration estimated by the Penman-Monteith model for winter wheat(Triticum aestivum), and (ii) for which soil water potentials in the root zone, the root water uptake and sap flow rates in crop stems would be reduced. Therefore, we measured sap flow velocities by an improved heat-balance approach (Langensiepen et al., 2014), calculated crop transpiration by Penman-Monteith model, and simulated root water uptake by HYDRUS-1D on an hourly scale for different soil water status in winter wheat. In order to assess the effects of soil water potential on root water uptake and sap flow, an average soil water potential was calculated by weighting the soil water potential at a certain depth with the root length density. The temporal evolution of root length density was measured using horizontal rhizotubes that were installed at different depths.The results showed that root water uptake and sap flow matched well with the computed transpiration by Penman-Monteith model in winter wheat when the soil water potential was not limiting root water uptake. However, low soil water content restrained root water uptake, especially when soil water potential was lower than -90 kPa in the top soil. Sap flow in wheat was not affected by the observed soil water conditions, suggesting that stomatal conductance was not sensitive to soil water potentials. The effect of drought stress on root water uptake and sap flow in winter wheat was only investigated in a short time (after anthesis). Further research could focus on a long time (e.g. from vegetation to maturity) effect under different soil water conditions, such as irrigated, sheltered and normal status. Langensiepen, M., Kupisch, M., Graf, A., Schmidt, M. and Ewert, F., 2014. Improving the stem heat balance method for determining sap-flow in wheat. Agricultural and Forest Meteorology, 186: 34-42.

Apical extrusion of debris and irrigants using hand and three rotary instrumentation systems − An in vitro study.

PubMed

Madhusudhana, Koppolu; Mathew, Vinod Babu; Reddy, Nelaturi Madhusudhan

2010-10-01

Sterilization of the root canal is a prime aim of successful endodontics. The cleaning and shaping of the canal is directed as achieving this goal. The extrusion of apical debris has a deleterious effect on the prognosis of root canal treatment. Several instrument designs and instrumentation techniques have been developed to prevent this. Forty caries free single rooted human mandibular premolar teeth were divided in four groups of ten teeth each. Teeth in each group were instrumented until the working length with rotary ProTaper, K3, Mtwo systems, and hand K-type stainless steel files. Debris and irrigant extruded from the apical foramen were collected into vials and the amounts were quantitatively determined. The data obtained were analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests. The results show that all instrumentation techniques produced significant amount of extruded debris and irrigant. The engine-driven nickel-titanium systems showed less apical extrusion of debris and irrigant than manual technique. No statistically significant difference was found between the groups at [P > 0.05]. Maximum apical debris and irrigant extrusion was seen with K-file group and least in the Mtwo group. The use of rotary files and techniques to perform instrumentation does show less extrusion of the debris and irrigant from the apex. This can contribute to more successful endodontic therapy.

Antibacterial properties of root canal lubricants: a comparison with commonly used irrigants.

PubMed

Wong, Samantha; Mundy, Lance; Chandler, Nicholas; Upritchard, Jenine; Purton, David; Tompkins, Geoffrey

2014-12-01

The aim was to assess in vitro the antibacterial activity of 10 root canal lubricants. K-Y Jelly personal lubricant, RC-Prep, File-Eze, File-Rite, EndoPrep Gel, Endosure Prep Crème 15%, Prep-Rite, Glyde, SlickGel ES and Alpha Glide were selected and compared in their antimicrobial properties to seven irrigants. Serial dilutions of each agent in tryptic soy broth were inoculated with either Enterococcus faecalis or Pseudomonas aeruginosa and incubated at 37C for 24 h. During incubation bacterial growth was measured by optical density (A(600)), and samples removed for cultivation on tryptic soy broth agar. Against both test bacteria after 1 h incubation, six lubricants recorded minimum bactericidal concentrations ranging from 1/10 to 1/80, whereas the inhibitory activity of the irrigants ranged from 1/20 to 1/640. Under these conditions, several lubricants exhibited antimicrobial activity comparable with some irrigants. Three irrigants, Consepsis (containing chlorhexidine), Endosure EDTA/C (containing cetrimide) and EndoPrep Solution (containing cetrimide), showed superior antibacterial action to lubricants against both species. The irrigants containing ethylenediamine tetraacetic acid and cetrimide were the most effective against both bacterial species at all time intervals. Antimicrobial activity of the lubricants did not correlate to pH values, which ranged from 2.9 to 10.3. Root canal lubricants have antibacterial properties that may help to disinfect canals. © 2014 Australian Society of Endodontology.

An in vivo comparison of antimicrobial efficacy of sodium hypochlorite and Biopure MTAD™ against enterococcus faecalis in primary teeth: A qPCR study.

PubMed

Tulsani, S G; Chikkanarasaiah, N; Bethur, S

2014-01-01

Biopure MTAD™, a new root canal irrigant has shown promising results against the most common resistant microorganism, E. faecalis, in permanent teeth. However, there is lack of studies comparing its antimicrobial effectiveness with NaOCl in primary teeth. The purpose of this study was to compare the in vivo antimicrobial efficacy of NaOCl 2.5% and Biopure MTAD™ against E. faecalis in primary teeth. Forty non vital single rooted primary maxillary anterior teeth of children aged 4-8 years, were irrigated either with NaOCl 2.5% (n=15), Biopure MTAD™ (n=15) and 0.9% Saline (n=10, control group). Paper point samples were collected at baseline (S1) and after chemomechanical preparation (S2) during the pulpectomy procedure. The presence of E. faecalis in S1 & S2 was evaluated using Real time Polymerase Chain Reaction. Statistical significant difference was found in the antimicrobial efficacy of NaOCl 2.5 % and BioPure MTAD™ when compared to saline (p>0.05). However, no statistical significant difference was found between the efficacies of both the irrigants. NaOCl 2.5% and BioPure MTAD™, both irrigants are equally efficient against E. faecalis in necrotic primary anterior teeth. MTAD is a promising irrigant, however clinical studies are required to establish it as ideal root canal irrigant in clinical practice.

Research on lettuce growth technology onboard Chinese Tiangong II Spacelab

NASA Astrophysics Data System (ADS)

Shen, Yunze; Guo, Shuangsheng; Zhao, Pisheng; Wang, Longji; Wang, Xiaoxia; Li, Jian; Bian, Qiang

2018-03-01

Lettuce was grown in a space vegetable cultivation facility onboard the Tiangong Ⅱ Spacelab during October 18 to November 15, 2016, in order to testify the key cultivating technology in CELSS under spaceflight microgravity condition. Potable water was used for irrigation of rooting substrate and the SRF (slowly released fertilizer) offered mineral nutrition for plant growth. Water content and electric conductivity in rooting substrate were measured based on FDR(frequency domain reflectometry) principle applied first in spaceflight. Lettuce germinated with comparative growth vigor as the ground control, showing that the plants appeared to be not stressed by the spaceflight environment. Under microgravity, lettuce grew taller and showed deeper green color than the ground control. In addition, the phototropism of the on-orbit plants was more remarkable. The nearly 30-d spaceflight test verified the seed fixation technology and water& nutrition management technology, which manifests the feasibility of FDR being used for measuring moisture content and electric conductivity in rooting zone under microgravity. Furthermore, the edibility of the space-grown vegetable was proved, providing theoretical support for astronaut to consume the space vegetable in future manned spaceflight.

Effects of different sonic activation protocols on debridement efficacy in teeth with single-rooted canals

PubMed Central

Niu, Li-na; Luo, Xiao-juan; Li, Guo-hua; Bortoluzzi, Eduardo A.; Mao, Jing; Chen, Ji-hua; Gutmann, James L.; Pashley, David H.; Tay, Franklin R.

2014-01-01

Objectives The effects of different EndoActivator® (EA) sonic activation protocols on root canal debridement efficacy were examined. Methods Root canals in 48 single-rooted teeth were instrumented, irrigated initially with NaOCl and divided into 6 groups (N=8) based on the application time of QMix (antimicrobial calcium-chelating irrigant), and the time and sequence of EA irrigant activation - Positive Control: 90 sec QMix; Negative Control: 90 sec saline; Group 1A: 15 sec QMix + 15 sec QMix with EA-activation; Group 1B: 30 sec QMix + 30 sec of QMix with EA-activation; Group 2A: 15 sec QMix with EA-activation + 15 sec QMix; Group 2B: 30 sec QMix with EA-activation + 30 sec QMix. Split roots were examined with scanning electron microscopy for assignment of smear and debris scores in locations along the coronal, middle and apical thirds of the canals. The overall cleanliness of pooled canal locations in the Positive Control and the 4 experimental groups were compared with chi-square tests. Results Significant differences were detected among the 5 groups (p<0.001). Post-hoc pairwise comparisons indicated that the overall canal cleanliness was in the order (from best to worst): 1B = 2B > 2A > 1A > Positive Control. Completely clean canals could not be achieved due to the absence of continuous irrigant flow for EA to clear intraradicular debris. Conclusions Irrespective of the sonic activation sequence, irrigant activation for 30 seconds during a 60-second period of QMix application appears to maximize the smear layer and debris removal potential of the EndoActivator® system. PMID:24878251

Oral tissue complications during endodontic irrigation: literature review.

PubMed

Kishor, Nanda

2013-04-01

The literature concerning the etiology, symptomatology and management of complications during root canal irrigation is reviewed. Clinical symptoms are discussed, as well as preventive and therapeutic considerations.

Antimicrobial Activity of Photodynamic Therapy Against Enterococcus faecalis Before and After Reciprocating Instrumentation in Permanent Molars.

PubMed

Pinheiro, Sérgio Luiz; Azenha, Giuliana Rodrigues; Democh, Yasmin Marialva; Nunes, Daniela Camila; Provasi, Silvia; Fontanetti, Giovana Masiero; Duarte, Danilo Antônio; Fontana, Carlos Eduardo; da Silveira Bueno, Carlos Eduardo

2016-12-01

The present study sought to evaluate the antimicrobial activity against Enterococcus faecalis of photodynamic therapy applied before and after reciprocating instrumentation of permanent molars. Apical extrusion of debris can cause flare-ups due to introduction of bacteria into the periapical tissues. Eighteen mesial roots from permanent mandibular molars were selected. The crowns were removed to obtain a standard root length of 15 mm. The included mesial roots had an angulation of 10°-40° and canals with independent foramina. The orifice of each mesiolingual canal was sealed with light-curing resin, and the working length was established visually, 1 mm short of the apical foramen. The roots were rendered impermeable and sterilized, and the mesiobuccal canals were contaminated with a standard strain of E. faecalis for 21 days. Specimens were randomly divided into three groups (n = 6): G1, photodynamic therapy performed before instrumentation and irrigation with 0.9% NaCl (saline) solution; G2, photodynamic therapy performed after instrumentation and irrigation with 0.9% NaCl; and G3 (control), instrumentation and irrigation with 2.5% NaOCl (sodium hypochlorite) solution. Canals were shaped with a WaveOne primary file (25.08) and irrigated with 0.9% NaCl. E. faecalis samples were collected before and after each procedure, and the results were analyzed using descriptive statistics and the Kruskal-Wallis and Wilcoxon tests. Significant reductions in E. faecalis were observed when photodynamic therapy was performed before and after instrumentation of the root canal system (p < 0.05). Reciprocating instrumentation significantly reduced E. faecalis colonies in experimentally contaminated root canal systems (p < 0.05). Photodynamic therapy was effective in removing E. faecalis from the root canal system, whether performed before or after reciprocating instrumentation.

Efficacy of irrigation systems on penetration of sodium hypochlorite to working length and to simulated uninstrumented areas in oval shaped root canals.

PubMed

de Gregorio, C; Paranjpe, A; Garcia, A; Navarrete, N; Estevez, R; Esplugues, E O; Cohenca, N

2012-05-01

To assess the ability of sodium hypochlorite (NaOCl) to penetrate simulated lateral canals and to reach working length (WL) when using the self-adjusting file (SAF). Seventy single-rooted teeth with oval-shaped canals were used. Upon access, presence of a single canal was confirmed by direct visualization under a dental-operating microscope. Canal length and patency were obtained using a size 10 K-file and root length standardized to 18 mm. Pre-enlargement was restricted to the coronal one-third. The apical size of each canal was gauged at WL and samples larger than size 30 were excluded. Canals were instrumented for 5 min using the SAF system while delivering a total of 20 mL of 5.25% NaOCl and 5 mL of 17% EDTA. Then, the apical diameters were standardized to size 35 using hand files. Four hundred and twenty simulated lateral canals were then created during the clearing process and roots coated with wax to create a closed system. All samples were then cleared and randomly assigned to four experimental groups: 1 (n = 15) positive pressure; 2 (n = 15) SAF without pecking motion; 3 (n = 15) SAF with pecking motion; 4 (n = 15) apical negative pressure (ANP) irrigation and (n = 10) control groups. Samples were scored on the basis of the ability of the contrast solution to reach WL and permeate into the simulated lateral canals to at least 50% of the total length. The Kruskal-Wallis test was used to analyse irrigant penetration and the Tukey test to determine statistical differences between groups (P < 0.05). All samples irrigated with ANP were associated with irrigant penetration to WL (Table 1). The differences between group 4 (ANP) and all other groups were significant in penetration to WL (P < 0.05). The pecking motion allowed for further penetration of the irrigant when using the SAF system but failed to irrigate at WL. None of the experimental groups demonstrated predictable irrigation of simulated lateral canals. In this laboratory model, ANP was the only delivery system capable of irrigating consistently to full WL. None of the systems tested produced complete irrigation in artificial lateral canals. © 2012 International Endodontic Journal.

Ultrasonic activation and chemical modification of photosensitizers enhances the effects of photodynamic therapy against Enterococcus faecalis root-canal isolates.

PubMed

Tennert, C; Drews, A M; Walther, V; Altenburger, M J; Karygianni, L; Wrbas, K T; Hellwig, E; Al-Ahmad, A

2015-06-01

The aim of this study was to evaluate the effect of photodynamic therapy (PDT) on Enterococcus faecalis biofilms in artificially infected root canals using modified photosensitizers and passive ultrasonic activation. Two hundred and seventy extracted human teeth with one root canal were instrumented utilizing ProTaper files, autoclaved, infected with E. faecalis T9 for 72 h and divided into different groups: irrigation with 3% sodium hypochlorite (NaOCl), 20% ethylenediaminetetraacetic acid (EDTA), or 20% citric acid, PDT without irrigation, PDT accompanied by irrigation with NaOCl, EDTA, or citric acid, PDT using an EDTA-based photosensitizer or a citric-acid-based photosensitizer and PDT with ultrasonic activation of the photosensitizer. A 15 mg/ml toluidine blue served as the photosensitizer, activated by a 100 mW LED light source. Sterile paper points were used for sampling the root canals and dentin chips were collected to assess the remaining contamination after treatment. Samples were cultured on blood agar plates and colony forming units were quantified. PDT alone achieved a reduction in E. faecalis counts by 92.7%, NaOCl irrigation alone and combined with PDT by 99.9%. The antibacterial effects increased by the combination of irrigation using EDTA or citric acid and PDT compared to irrigation alone. More than 99% of E. faecalis were killed using PDT with the modified photosensitizers and ultrasonic activation. NaOCl based disinfection achieved the highest antimicrobial effect. Using PDT with an EDTA-based or citric-acid-based phozosensitizer or activating the photosensitizer with ultrasound resulted in a significantly higher reduction in E. faecalis counts compared to conventional PDT. Copyright © 2015 Elsevier B.V. All rights reserved.

Rice Performance and Water Use Efficiency under Plastic Mulching with Drip Irrigation

PubMed Central

He, Haibing; Ma, Fuyu; Yang, Ru; Chen, Lin; Jia, Biao; Cui, Jing; Fan, Hua; Wang, Xin; Li, Li

2013-01-01

Plastic mulching with drip irrigation is a new water-saving rice cultivation technology, but little is known on its productivity and water-saving capacity. This study aimed to assess the production potential, performance, and water use efficiency (WUE) of rice under plastic mulching with drip irrigation. Field experiments were conducted over 2 years with two rice cultivars under different cultivation systems: conventional flooding (CF), non-flooded irrigation incorporating plastic mulching with furrow irrigation (FIM), non-mulching with furrow irrigation (FIN), and plastic mulching with drip irrigation (DI). Compared with the CF treatment, grain yields were reduced by 31.76–52.19% under the DI treatment, by 57.16–61.02% under the FIM treatment, by 74.40–75.73% under the FIN treatment, which were mainly from source limitation, especially a low dry matter accumulation during post-anthesis, in non-flooded irrigation. WUE was the highest in the DI treatment, being 1.52–2.12 times higher than with the CF treatment, 1.35–1.89 times higher than with the FIM treatment, and 2.37–3.78 times higher than with the FIN treatment. The yield contribution from tillers (YCFTs) was 50.65–62.47% for the CF treatment and 12.07–20.62% for the non-flooded irrigation treatments. These low YCFTs values were attributed to the poor performance in tiller panicles rather than the total tiller number. Under non-flooded irrigation, root length was significantly reduced with more roots distributed in deep soil layers compared with the CF treatment; the DI treatment had more roots in the topsoil layer than the FIM and FIN treatments. The experiment demonstrates that the DI treatment has greater water saving capacity and lower yield and economic benefit gaps than the FIM and FIN treatments compared with the CF treatment, and would therefore be a better water-saving technology in areas of water scarcity. PMID:24340087

Carbon balance, partitioning and photosynthetic acclimation in fruit-bearing grapevine (Vitis vinifera L. cv. Tempranillo) grown under simulated climate change (elevated CO2, elevated temperature and moderate drought) scenarios in temperature gradient greenhouses.

PubMed

Salazar-Parra, Carolina; Aranjuelo, Iker; Pascual, Inmaculada; Erice, Gorka; Sanz-Sáez, Álvaro; Aguirreolea, Jone; Sánchez-Díaz, Manuel; Irigoyen, Juan José; Araus, José Luis; Morales, Fermín

2015-02-01

Although plant performance under elevated CO2 has been extensively studied in the past little is known about photosynthetic performance changing simultaneously CO2, water availability and temperature conditions. Moreover, despite of its relevancy in crop responsiveness to elevated CO2 conditions, plant level C balance is a topic that, comparatively, has received little attention. In order to test responsiveness of grapevine photosynthetic apparatus to predicted climate change conditions, grapevine (Vitis vinifera L. cv. Tempranillo) fruit-bearing cuttings were exposed to different CO2 (elevated, 700ppm vs. ambient, ca. 400ppm), temperature (ambient vs. elevated, ambient +4°C) and irrigation levels (partial vs. full irrigation). Carbon balance was followed monitoring net photosynthesis (AN, C gain), respiration (RD) and photorespiration (RL) (C losses). Modification of environment (13)C isotopic composition (δ(13)C) under elevated CO2 (from -10.30 to -24.93‰) enabled the further characterization of C partitioning into roots, cuttings, shoots, petioles, leaves, rachides and berries. Irrespective of irrigation level and temperature, exposure to elevated CO2 induced photosynthetic acclimation of plants. C/N imbalance reflected the inability of plants grown at 700ppm CO2 to develop strong C sinks. Partitioning of labeled C to storage organs (main stem and roots) did not avoid accumulation of labeled photoassimilates in leaves, affecting negatively Rubisco carboxylation activity. The study also revealed that, after 20 days of treatment, no oxidative damage to chlorophylls or carotenoids was observed, suggesting a protective role of CO2 either at current or elevated temperatures against the adverse effect of water stress. Copyright © 2014 Elsevier GmbH. All rights reserved.

Expanding the Annual Irrigation Maps (AIM) Product to the entire High Plains Aquifer (HPA): Addressing the Challenges of Cotton and Deficit-Irrigated Fields

NASA Astrophysics Data System (ADS)

Rapp, J. R.; Deines, J. M.; Kendall, A. D.; Hyndman, D. W.

2017-12-01

The High Plains Aquifer (HPA) is the most extensively irrigated aquifer in the continental United States and is the largest major aquifer in North America with an area of 500,000 km2. Increased demand for agricultural products has led to expanded irrigation extent, but brought with it declining groundwater levels that have made irrigation unsustainable in some locations. Understanding these irrigation dynamics and mapping irrigated areas through time are essential for future sustainable agricultural practices and hydrological modeling. Map products using remote sensing have only recently been able to track annual dynamics at relatively high spatial resolution (30 m) for a large portion of the northern HPA. However follow-on efforts to expand these maps to the entire HPA have met with difficulty due to the challenge of distinguishing irrigation in crop types that are commonly deficit- or partially-irrigated. Expanding these maps to the full HPA requires addressing unique features of partially irrigated fields and irrigated cotton, a major water user in the southern HPA. Working in Google Earth Engine, we used all available Landsat imagery to generate annual time series of vegetation indices. We combined this information with climate covariables, planting dates, and crop specific training data to algorithmically separate fully irrigated, partially irrigated, and non-irrigated field locations. The classification scheme was then applied to produce annual maps of irrigation across the entire HPA. The extensive use of ancillary data and the "greenness" time series for the algorithmic classification generally increased accuracy relative to previous efforts. High-accuracy, representative map products of irrigation extent capable of detecting crop type and irrigation intensity within aquifers will be an essential tool to monitor the sustainability of global aquifers and to provide a scientific bases for political and economic decisions affecting those aquifers.

Evaluation of potential water conservation using site-specific irrigation

USDA-ARS?s Scientific Manuscript database

With the advent of site-specific variable-rate irrigation (VRI) systems, irrigation can be spatially managed within sub-field-sized zones. Spatial irrigation management can optimize spatial water use efficiency and may conserve water. Spatial VRI systems are currently being managed by consultants ...

Comparison of the Antimicrobial Efficacy of the EndoVac System and Conventional Needle Irrigation in Primary Molar Root Canals.

PubMed

Buldur, Burak; Kapdan, Arife

The purpose of this study was to compare the antimicrobial efficacy of the EndoVac system and conventional needle irrigation to eliminate E faecalis in primary molar root canals. 60 extracted human primary second molar roots were instrumented up to an apical size .04/35 and randomly divided into two groups; Group 1: conventional needle (n=30) and Group 2: EndoVac (n=30), and four subgroups (two experimental subgroups; (a) 2.5% sodium hypochlorite (NaOCl) + ethylenediaminetetraacetic acid (EDTA) (n=20), (b) ozonated water (OW) + EDTA (n=20), and control groups (c) 5.25% NaOCl (n=10) and (d) saline (n=10). All roots were sterilized and then inoculated with E.faecalis. Before and after final irrigation procedures, root canals were sampled and the grown colony forming units (CFUs) were counted. Data were analyzed by Kruskall-Wallis and Mann-Whitney U tests using a 0.05 significance level. The EndoVac reduced more bacteria than the conventional needle did but it was not statistically significant (p>0.05). NaOCl alone or followed by EDTA totally eliminated bacteria. OW + EDTA showed higher reduction of bacteria but could not totally eliminate bacterias. In the context of bacterial elimination, the EndoVac was not significantly better than the conventional needle. Although, there were fewer CFU/mg when using EndoVac, there was not any statistically significant superiority to conventional needle irrigation. An OW+EDTA regimen showed antibacterial effect in the primary molar root canals but it was significantly less effective than NaOCl+EDTA.

Downscaling Satellite Data for Predicting Catchment-scale Root Zone Soil Moisture with Ground-based Sensors and an Ensemble Kalman Filter

NASA Astrophysics Data System (ADS)

Lin, H.; Baldwin, D. C.; Smithwick, E. A. H.

2015-12-01

Predicting root zone (0-100 cm) soil moisture (RZSM) content at a catchment-scale is essential for drought and flood predictions, irrigation planning, weather forecasting, and many other applications. Satellites, such as the NASA Soil Moisture Active Passive (SMAP), can estimate near-surface (0-5 cm) soil moisture content globally at coarse spatial resolutions. We develop a hierarchical Ensemble Kalman Filter (EnKF) data assimilation modeling system to downscale satellite-based near-surface soil moisture and to estimate RZSM content across the Shale Hills Critical Zone Observatory at a 1-m resolution in combination with ground-based soil moisture sensor data. In this example, a simple infiltration model within the EnKF-model has been parameterized for 6 soil-terrain units to forecast daily RZSM content in the catchment from 2009 - 2012 based on AMSRE. LiDAR-derived terrain variables define intra-unit RZSM variability using a novel covariance localization technique. This method also allows the mapping of uncertainty with our RZSM estimates for each time-step. A catchment-wide satellite-to-surface downscaling parameter, which nudges the satellite measurement closer to in situ near-surface data, is also calculated for each time-step. We find significant differences in predicted root zone moisture storage for different terrain units across the experimental time-period. Root mean square error from a cross-validation analysis of RZSM predictions using an independent dataset of catchment-wide in situ Time-Domain Reflectometry (TDR) measurements ranges from 0.060-0.096 cm3 cm-3, and the RZSM predictions are significantly (p < 0.05) correlated with TDR measurements [r = 0.47-0.68]. The predictive skill of this data assimilation system is similar to the Penn State Integrated Hydrologic Modeling (PIHM) system. Uncertainty estimates are significantly (p < 0.05) correlated to cross validation error during wet and dry conditions, but more so in dry summer seasons. Developing an EnKF-model system that downscales satellite data and predicts catchment-scale RZSM content is especially timely, given the anticipated release of SMAP surface moisture data in 2015.

Management of Chronic Periodontitis Using Subgingival Irrigation of Ozonized Water: A Clinical and Microbiological Study

PubMed Central

Mathew, Jayan Jacob; Ambooken, Majo; Kachappilly, Arun Jose; PK, Ajithkumar; Johny, Thomas; VK, Linith; Samuel, Anju

2015-01-01

Introduction Adjunctive use of professional subgingival irrigation with scaling and root planing (SRP) has been found to be beneficial in eradicating the residual microorganisms in the pocket. Objective To evaluate the effect of ozonized water subgingival irrigation on microbiologic parameters and clinical parameters namely Gingival index, probing pocket depth, and clinical attachment level. Materials and Methods Thirty chronic periodontitis patients with probing pocket depth ≥6mm on at least one tooth on contra lateral sides of opposite arches were included in the study. The test sites were subjected to ozonized water subgingival irrigation with subgingival irrigation device fitted with a modified subgingival tip. Control sites were subjected to scaling and root planing only. The following clinical parameters were recorded initially and after 4 weeks at the test sites and control sites. Plaque Index, Gingival Index, probing pocket depth, clinical attachment level. Microbiologic sampling was done for the test at the baseline, after scaling, immediately after ozonized water subgingival irrigation and after 4 weeks. In control sites microbiologic sampling was done at the baseline, after scaling and after 4 weeks. The following observations were made after 4 weeks. The results were statistically analysed using independent t-test and paired t-test. Result Test sites showed a greater reduction in pocket depth and gain in clinical attachment compared to control sites. The total anaerobic counts were significantly reduced by ozonized water subgingival irrigation along with SRP compared to SRP alone. Conclusion Ozonized water subgingival irrigation can improve the clinical and microbiological parameters in patients with chronic periodontitis when used as an adjunct to scaling and root planing. PMID:26436042

Nutrition and irrigation regime affect size and early growth of white oak seedlings

Treesearch

Paul P. Kormanik; Shi-Jean S. Sung; Taryn L. Kormanik; Thomas Tibbs; Stanley J. Zarnoch

2003-01-01

Modifications of our nursery protocol for oaks during 1997 and 1998 by instituting dormant season irrigation resulted in high white oak seedling quality. The improved growth was associated with the consistent presence of succulent fibrous roots on the upper 10 to 15 cm of taproots. Many of these fibrous roots on 1-1 stock were as sturdy as many of the permanent first-...

Three rooted, four canalled mandibular first molar (Radix Entomolaris).

PubMed

Parolia, Abhishek; Kundabala, M; Thomas, M S; Mohan, M; Joshi, N

2009-01-01

A mandibular first molar with two distal roots is an interesting example of anatomic variation. This paper describes case reports of mandibular first molar with three roots (one mesial and two distal) and four canals (two in mesial and one in each distobuccal and distolingual root). The canals were shaped with protaper rotary files and irrigated with 5.25% sodium hyochlorite, 0.2 %w/v of chlorhexidine gluconate and normal saline as the fi nal irrigant. The canals were then obturated with gutta- percha and AH plus sealer. These case reports show an anatomic variation of internal morphology of the tooth and points out the importance of searching for additional canals.

A reconnaissance study of the effect of irrigated agriculture on water quality in the Ogallala Formation, Central High Plains Aquifer

USGS Publications Warehouse

McMahon, Peter B.

2000-01-01

In 1998, the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program began a regional study of water quality in the High Plains aquifer. The High Plains aquifer underlies an area of about 174,000 square miles in parts of eight States. Because of its large size, the High Plains aquifer has been divided into three regions: the Southern High Plains, Central High Plains, and Northern High Plains. Although an assessment of water quality in each of the three regions is planned, the initial focus will be the Central High Plains aquifer. Anyone who has flown over the Central High Plains in the summer and has seen the large green circles associated with center pivot sprinklers knows that irrigated agriculture is a widespread land use. Pesticides and fertilizers applied on those irrigated fields will not degrade ground-water quality if they remain in or above the root zone. However, if those chemicals move downward through the unsaturated zone to the water table, they may degrade the quality of the ground water. Water is the principal agent for transporting chemicals from land surface to the water table, and in the semiarid Central High Plains, irrigation often represents the most abundant source of water during the growing season. One objective of NAWQA's High Plains Regional Ground-Water study is to evaluate the effect of irrigated agriculture on the quality of recently recharged water in the Ogallala Formation of the Central High Plains aquifer. The Ogallala Formation is the principal geologic unit in the Central High Plains aquifer, and it consists of poorly sorted clay, silt, sand, and gravel that generally is unconsolidated (Gutentag and others, 1984). Approximately 23 percent of the cropland overlying the Ogallala Formation is irrigated (U.S. Department of Agriculture, 1999). The NAWQA Program generally defines recently recharged ground water to be water recharged in the last 50 years. The water table in the Ogallala Formation is separated from overlying land-use practices by as much as 400 feet of unsaturated sediments. Consequently, one may hypothesize that recently recharged water is not present in the formation. The U.S. Geological Survey conducted a reconnaissance study in 1999 to establish (a) if recently recharged water was present in the Ogallala Formation underlying irrigated cropland and (b) if agricultural land-use practices affect water quality. Results from the reconnaissance study will be used to determine whether a full-scale land-use study is warranted.

Water balance analysis for efficient water allocation in agriculture. A case study: Balta Brailei, Romania

NASA Astrophysics Data System (ADS)

Chitu, Zenaida; Villani, Giulia; Tomei, Fausto; Minciuna, Marian; Aldea, Adrian; Dumitrescu, Alexandru; Trifu, Cristina; Neagu, Dumitru

2017-04-01

Balta Brailei is one of the largest agriculture area in the Danube floodplain, located in SE of Romania. An impressive irrigation system, that covered about 53.500 ha and transferred water from the Danube River, was carried out in the period 1960-1980. Even if the water resources for agriculture in this area cover in most of the cases the volumes required by irrigation water users, the irrigation infrastructure issues as the position of the pumping stations against the river levels hinder the use of the water during low flows periods. An efficient optimization of water allocation in agriculture could avoid periods with water deficit in the irrigation systems. Hydrological processes are essentials in describing the mass and energy exchanges in the atmosphere-plant-soil system. Furthermore, the hydrological regime in this area is very dynamic with many feedback mechanisms between the various parts of the surface and subsurface water regimes. Agricultural crops depend on capillary rise from the shallow groundwater table and irrigation. For an effective optimization of irrigation water in Balta Brailei, we propose to analyse the water balance taking into consideration the water movement into the root zone and the influence of the Danube river, irrigation channel system and the shallow aquifer by combining the soil water balance model CRITERIA and GMS hydrogeological model. CRITERIA model is used for simulating water movement into the soil, while GMS model is used for simulating the shallow groundwater level variation. The understanding of the complex feedbacks between atmosphere, crops and the various parts of the surface and subsurface water regimes in the Balta Brailei will bring more insights for predicting crop water need and water resources for irrigation and it will represent the basis for implementing Moses Platform in this specific area. Moses Platform is a GIS based system devoted to water procurement and management agencies to facilitate planning of irrigation water resources. This work is financed by the European Union's H2020 research and innovation programme under grant agreement No 642258 (Moses Project).

Antimicrobial activity of sodium hypochlorite in endodontics.

PubMed

Mohammadi, Zahed; Shalavi, Sousan

2013-01-01

One of the major objectives in endodontic therapy is to disinfect the entire root canal system. This goal may be achieved using mechanical instrumenation and chemical irrigation in conjunrction with medication of the root canal between treatment sessions. Microorganisms and their by-products are considered to be the major cause of pulpal and periradicular patholic. In order to reduce or eliminate bacteria and popular tissue remnants, the use of various irrigation solution during treatment have been suggested. Sodium hypochlorite (NaOCI), the most common irrigant, is an excellent nonspecific proteolytic and antimicrobial agent. The purpose of this paper is to review the antimicrobial activity of sodium hypochlorite.

Comparison of Vibringe, EndoActivator, and needle irrigation on sealer penetration in extracted human teeth.

PubMed

Bolles, Jordan A; He, Jianing; Svoboda, Kathy K H; Schneiderman, Emet; Glickman, Gerald N

2013-05-01

Vibringe is a new device that allows continuous sonic irrigation of the canal system during endodontic treatment. The aim of this study was to compare the effect of different irrigation systems on sealer penetration into dentinal tubules of extracted single-rooted teeth. Fifty single-rooted human teeth were instrumented and randomly divided into 4 groups: group 1 (control), saline; group 2 (conventional irrigation), 17% EDTA followed by 6% NaOCl; group 3 (EndoActivator), same irrigants as group 2; group 4 (Vibringe), same irrigants as group 2. Obturation of all teeth was done with gutta-percha and SimpliSeal labeled with fluorescent dye. Transverse sections at 1 mm and 5 mm from the root apex were examined by using confocal laser scanning microscopy. Percentage and maximum depth of sealer penetration were measured by using NIS-Elements Br 3.0 imaging software. Groups 3 and 4 had a significantly greater percentage of the canal wall penetrated by sealer at the 5-mm level than group 1 (P < .0125), but not group 2. No other differences were found between the groups at either section level for both the percentage of sealer penetration and maximum depth. The 5-mm sections in each experimental group had a significantly higher percentage and maximum depth of sealer penetration than did the 1-mm sections (P < .0125). The use of sonic activation with either the EndoActivator or Vibringe did not significantly improve the sealer penetration when compared with conventional irrigation. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Uptake and distribution of minerals and heavy metals in commonly grown leafy vegetable species irrigated with sewage water.

PubMed

Anwar, Sumera; Nawaz, Muhammad Farrakh; Gul, Sadaf; Rizwan, Muhammad; Ali, Shafaqat; Kareem, Arshaad

2016-09-01

Heavy metal uptake and accumulation behavior in dietary vegetables irrigated with sewage waters is an important issue worldwide. The main objective of this study was to examine and compare the physiological and growth responses of leafy vegetables irrigated with sewage water. A pot experiment was conducted in a wire house with three leafy vegetables, coriander (Coriandrum sativum), mint (Mentha arvensis), and fenugreek (Trigonella foenum), grown under ambient conditions. Plants were irrigated with different concentrations, 0, 50 (T 1), and 100 % (T 2), of sewage water. After harvesting, morphological and physiological parameters of plants were measured. Heavy metal (Cd, Cu, Pb, and Zn) concentrations in the sewage water were found much higher than safer limits. The results revealed that the highest plant biomass and lowest metal contents were observed in control treatments in all studied vegetables. The biomass of all the vegetables were negatively affected when irrigated with sewage water. In T 2, coriander accumulated maximum Cd (μg g(-1) DW) in shoots (4.97) as compared to other vegetables. The maximum Pb and Cu concentrations were accumulated in mint roots (44 and 3.9, respectively) as compared to coriander and fenugreek. Zinc was accumulated in the sequence of leaves > roots > shoots under polluted water irrigation. The concentrations of potassium increased in leaves, shoots, and roots in all vegetables, while phosphorous concentrations varied with species and plant parts with increasing sewage water concentration. It was found that the leafy vegetables grown with sewage water irrigation may cause severe human health problems.

Changes in fine-root production, phenology and spatial distribution in response to N application in irrigated sweet cherry trees.

PubMed

Artacho, Pamela; Bonomelli, Claudia

2016-05-01

Factors regulating fine-root growth are poorly understood, particularly in fruit tree species. In this context, the effects of N addition on the temporal and spatial distribution of fine-root growth and on the fine-root turnover were assessed in irrigated sweet cherry trees. The influence of other exogenous and endogenous factors was also examined. The rhizotron technique was used to measure the length-based fine-root growth in trees fertilized at two N rates (0 and 60 kg ha(-1)), and the above-ground growth, leaf net assimilation, and air and soil variables were simultaneously monitored. N fertilization exerted a basal effect throughout the season, changing the magnitude, temporal patterns and spatial distribution of fine-root production and mortality. Specifically, N addition enhanced the total fine-root production by increasing rates and extending the production period. On average, N-fertilized trees had a length-based production that was 110-180% higher than in control trees, depending on growing season. Mortality was proportional to production, but turnover rates were inconsistently affected. Root production and mortality was homogeneously distributed in the soil profile of N-fertilized trees while control trees had 70-80% of the total fine-root production and mortality concentrated below 50 cm depth. Root mortality rates were associated with soil temperature and water content. In contrast, root production rates were primarily under endogenous control, specifically through source-sink relationships, which in turn were affected by N supply through changes in leaf photosynthetic level. Therefore, exogenous and endogenous factors interacted to control the fine-root dynamics of irrigated sweet cherry trees. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Changes in fine-root production, phenology and spatial distribution in response to N application in irrigated sweet cherry trees

PubMed Central

Artacho, Pamela; Bonomelli, Claudia

2016-01-01

Factors regulating fine-root growth are poorly understood, particularly in fruit tree species. In this context, the effects of N addition on the temporal and spatial distribution of fine-root growth and on the fine-root turnover were assessed in irrigated sweet cherry trees. The influence of other exogenous and endogenous factors was also examined. The rhizotron technique was used to measure the length-based fine-root growth in trees fertilized at two N rates (0 and 60 kg ha−1), and the above-ground growth, leaf net assimilation, and air and soil variables were simultaneously monitored. N fertilization exerted a basal effect throughout the season, changing the magnitude, temporal patterns and spatial distribution of fine-root production and mortality. Specifically, N addition enhanced the total fine-root production by increasing rates and extending the production period. On average, N-fertilized trees had a length-based production that was 110–180% higher than in control trees, depending on growing season. Mortality was proportional to production, but turnover rates were inconsistently affected. Root production and mortality was homogeneously distributed in the soil profile of N-fertilized trees while control trees had 70–80% of the total fine-root production and mortality concentrated below 50 cm depth. Root mortality rates were associated with soil temperature and water content. In contrast, root production rates were primarily under endogenous control, specifically through source–sink relationships, which in turn were affected by N supply through changes in leaf photosynthetic level. Therefore, exogenous and endogenous factors interacted to control the fine-root dynamics of irrigated sweet cherry trees. PMID:26888890

Morphological alterations of radicular dentine pretreated with different irrigating solutions and irradiated with 980-nm diode laser.

PubMed

Alfredo, Edson; Souza-Gabriel, Aline E; Silva, Silvio Rocha C; Sousa-Neto, Manoel D; Brugnera-Junior, Aldo; Silva-Sousa, Yara T C

2009-01-01

The topographical features of intraradicular dentine pretreated with sodium hypochlorite (NaOCl) or ethylenediamine tetraacetic acid (EDTA) followed by diode laser irradiation have not yet been determined. To evaluate the alterations of dentine irradiated with 980-nm diode laser at different parameters after the surface treatment with NaOCl and EDTA. Roots of 60 canines were biomechanically prepared and irrigated with NaOCl or EDTA. Groups were divided according to the laser parameters: 1.5 W/CW; 1.5 W/100 Hz; 3.0 W/CW; 3.0 W/100 Hz and no irradiation (control). The roots were splited longitudinally and analyzed by scanning electron microscopy (SEM) in a quali-quatitative way. The scores were submitted to two-way Kruskal-Wallis and Dunn's tests. The statistical analysis demonstrated that the specimens treated only with NaOCl or EDTA (control groups) were statistically different (P < 0.05) from the laser-irradiated specimens, regardless of the parameter setting. The specimens treated with NaOCl showed a laser-modified surface with smear layer, fissures, and no visible tubules. Those treated with EDTA and irradiated by laser presented absence of smear layer, tubules partially exposed and melting areas. The tested parameters of 980-nm diode laser promoted similar alterations on dentine morphology, dependent to the type of surface pretreatment. Copyright 2008 Wiley-Liss, Inc.

Health risk assessment and growth characteristics of wheat and maize crops irrigated with contaminated wastewater.

PubMed

Farahat, Emad A; Galal, Tarek M; Elawa, Omar E; Hassan, Loutfy M

2017-10-02

The present study evaluated the effect of untreated wastewater irrigation and its health risks in Triticum aestivum (wheat) and Zea mays (maize) cultivated at south Cairo, Egypt. Morphological measurements (stem and root lengths, number of leaves per plant, and dry weights of main organs) as well as soil, irrigation water, and plant analyses for nutrients and heavy metals were conducted in polluted and unpolluted sites. Wastewater irrigations leads to reduction in the morphological traits of the plants and reduced its vegetative biomass and yield production, with more negative impacts on maize than wheat. The concentrations of Pb, Cd, Cr, and Fe in roots and leaves of wheat were above the phytotoxic limits. Conversely, Pb, Cd, and Fe were significantly high and at phytotoxic concentrations in the leaves of maize at polluted site. The present study indicated that wheat plants tend to phytostabilize heavy metals in their roots, while maize accumulates it more in their leaves. Maize and wheat had toxic concentrations of Pb and Cd in their grains under wastewater irrigation. The health risk index showed values > 1 for Pb and Cd in polluted site for both crops, in addition to maize in unpolluted site. Consequently, this will have greatest potential to pose health risk to the consumers.

Comparison of the antimicrobial efficacy of irrigation using the EndoVac to endodontic needle delivery.

PubMed

Miller, Todd A; Baumgartner, J Craig

2010-03-01

The purpose of this investigation was to compare the antimicrobial efficacy of root canal irrigation with the EndoVac (Discus Dental, Culver City, CA) to endodontic needle irrigation in the apical 5 mm of root canals infected with Enterococcus faecalis. Bilaterally matched, extracted human teeth were sterilized and inoculated with E. faecalis. Specimens in the EndoVac group were irrigated using the EndoVac system, whereas those in the needle group were irrigated with a 30-G side-vented needle. After chemomechanical preparation, the apical 5 mm of the roots were removed, frozen in liquid nitrogen, and pulverized to expose E. faecalis in dentinal tubules or other morphologic irregularities. The number of colony forming units (cfus) of E. faecalis per mg dentin was determined. The EndoVac Group had a mean of 31.6 cfu/mg, whereas the needle group had a mean of 157 cfu/mg. This represents a bacterial reduction of 99.7% in group A and 98.8% in group B when compared with positive controls. Although there were fewer cfu/mg when using the EndoVac, there was not a statistically significant difference between the EndoVac and needle groups. Copyright (c) 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Effect of diode laser and ultrasonics with and without ethylenediaminetetraacetic acid on smear layer removal from the root canals: A scanning electron microscope study.

PubMed

Amin, Khalid; Masoodi, Ajaz; Nabi, Shahnaz; Ahmad, Parvaiz; Farooq, Riyaz; Purra, Aamir Rashid; Ahangar, Fayaz Ahmad

2016-01-01

To evaluate the effect of diode laser and ultrasonics with and without ethylenediaminetetraacetic acid (EDTA) on the smear layer removal from root canals. A total of 120 mandibular premolars were decoronated to working the length of 12 mm and prepared with protaper rotary files up to size F3. Group A canals irrigated with 1 ml of 3% sodium hypochlorite (NaOCl) followed by 3 ml of 3% NaOCl. Group B canals irrigated with 1 ml of 17% EDTA followed by 3 ml of 3% NaOCl. Group C canals lased with a diode laser. Group D canals were initially irrigated with 0.8 ml of 17% EDTA the remaining 0.2 ml was used to fill the root canals, and diode laser application was done. Group E canals were irrigated with 1 ml distilled water with passive ultrasonic activation, followed by 3 ml of 3% NaOCl. Group F canals were irrigated with 1 ml EDTA with passive ultrasonic activation, followed by 3 ml of 3% NaOCl. Scanning electron microscope examination of canals was done for remaining smear layer at coronal middle and apical third levels. Ultrasonics with EDTA had the least smear layer scores. Diode laser alone performed significantly better than ultrasonics.

Comparative anti-microbial efficacy of Azadirachta indica irrigant with standard endodontic irrigants: A preliminary study

PubMed Central

Dutta, Arindam; Kundabala, Mala

2014-01-01

Objective: The anti-microbial efficacy of 2.5% sodium hypochlorite (SHC) and 0.2% chlorhexidine gluconate were compared with an experimental irrigant formulated from the Neem tree, Azadirachta indica A. Juss. Materials and Methods: A sample of 36 single rooted anterior teeth with periapical radiolucency and absence of response to vitality tests that required root canal treatment were selected for this study. The test irrigants and their combinations were assigned to five different groups and saline served as the control. Access cavities were prepared using an aseptic technique and samples collected for both anaerobic culture and Gram stained smears, followed by irrigation and sample collection again. The number of organisms were expressed in colony forming units/ml after 72 h of incubation; the smears were analyzed for their microbial loads and tissue clearance and assessed as per defined criteria. Results: Our results found the maximum reduction in microbial loads, when analyzed by culture method, with a combination of SHC and the experimental neem irrigant. Maximum tissue clearance on the Gram Stained smears was also found with the same combination. Conclusion: Neem irrigant has anti-microbial efficacy and can be considered for endodontic use. PMID:24778508

Effect of EDTA, sodium hypochlorite, and chlorhexidine gluconate with or without surface modifiers on dentin microhardness.

PubMed

Aslantas, Eda E; Buzoglu, Hatice Dogan; Altundasar, Emre; Serper, Ahmet

2014-06-01

This study aimed to evaluate the effects of root canal irrigants on the microhardness of root canal dentin in the presence and absence of surface-modifying agents. Forty-eight root halves were prepared by longitudinal splitting of the distal roots of 24 freshly extracted mandibular human third molars and embedded in autopolymerizing acrylic resin, leaving the dentin surface exposed. After polishing, the microhardness values of the untreated dentin surfaces were recorded by using Vickers tester at the mid-root level. The root halves were randomly assigned to 6 groups composed of 8 samples each and treated for 5 minutes with one of the following irrigants: 17% EDTA, REDTA, 2% chlorhexidine gluconate (CHX), 2% CHX with surface modifiers (CHX-Plus), 6% NaOCl, or 6% NaOCl with surface modifiers (Chlor-XTRA). After surface treatment, dentin microhardness values were recorded at close proximity to the initial indentation areas. Experimental data were statistically analyzed by using the t test and one-way analysis of variance, followed by Tukey honestly significant difference test at α = 0.05. EDTA, REDTA, NaOCl, and Chlor-XTRA significantly decreased the microhardness of root dentin compared with intact controls (P < .05). The addition of surface modifiers to the irrigants did not affect the microhardness of the samples. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Measured soil water evaporation as a function of the square root of time and reference ET

USDA-ARS?s Scientific Manuscript database

Sunflower (Helianthus annuus L.) is a drought-adapted crop with a short growing season that reduces irrigation requirements and makes it ideal for regions with limited irrigation water supplies. Our objectives were a) to evaluate the yield potential of sunflower under deficit irrigation and b) det...

Sodium and chloride accumulation in leaf, woody, and root tissue of Populus after irrigation with landfill leachate

Treesearch

Jill A. Zalesny; Ronald S., Jr. Zalesny; Adam H. Wiese; Bart Sexton; Richard B. Hall

2008-01-01

The response of Populus to irrigation sources containing elevated levels of sodium (Na+) and chloride (Cl-) is poorly understood. We irrigated eight Populus clones with fertilized well water (control) (N, P, K) or municipal solid waste landfill leachate weekly during 2005 and 2006 in...

HYDRUS-1D Modeling of an Irrigated Agricultural Plot with Application to Aquifer Recharge Estimation

USDA-ARS?s Scientific Manuscript database

A variety of methods are available for estimating aquifer recharge in semi-arid regions, each with advantages and disadvantages. We are investigating a procedure for estimating recharge in an irrigated basin. The method involves computing irrigation return flows based on HYDRUS-1D modeling of root z...

Colonic irrigation for defecation disorders after dynamic graciloplasty.

PubMed

Koch, Sacha M; Uludağ, Ozenç; El Naggar, Kadri; van Gemert, Wim G; Baeten, Cor G

2008-02-01

Dynamic graciloplasty (DGP) improves anal continence and quality of life for most patients. However, in some patients, DGP fails and fecal incontinence is unsolved or only partially improved. Constipation is also a significant problem after DGP, occurring in 13-90%. Colonic irrigation can be considered as an additional or salvage treatment for defecation disorders after unsuccessful or partially successful DGP. In this study, the effectiveness of colonic irrigation for the treatment of persistent fecal incontinence and/or constipation after DGP is investigated. Patients with defecation disorders after DGP visiting the outpatient clinic of the University Hospital Maastricht were selected for colonic irrigation as additional therapy or salvage therapy in the period between January 1999 and June 2003. The Biotrol(R) Irrimatic pump or the irrigation bag was used for colonic irrigation. Relevant physical and medical history was collected. The patients were asked to fill out a detailed questionnaire about colonic irrigation. Forty-six patients were included in the study with a mean age of 59.3 +/- 12.4 years (80% female). On average, the patients started the irrigation 21.39 +/- 38.77 months after the DGP. Eight patients started irrigation before the DGP. Fifty-two percent of the patients used the irrigation as additional therapy for fecal incontinence, 24% for constipation, and 24% for both. Irrigation was usually performed in the morning. The mean frequency of irrigation was 0.90 +/- 0.40 times per day. The mean amount of water used for the irrigation was 2.27 +/- 1.75 l with a mean duration of 39 +/- 23 min. Four patients performed antegrade irrigation through a colostomy or appendicostomy, with good results. Overall, 81% of the patients were satisfied with the irrigation. Thirty-seven percent of the patients with fecal incontinence reached (pseudo-)continence, and in 30% of the patients, the constipation completely resolved. Side effects of the irrigation were reported in 61% of the patients: leakage of water after irrigation, abdominal cramps, and distended abdomen. Seven (16%) patients stopped the rectal irrigation. Colonic irrigation is an effective alternative for the treatment of persistent fecal incontinence after DGP and/or recurrent or onset constipation additional to unsuccessful or (partially) successful DGP.

Uptake and Accumulation of Pharmaceuticals in Lettuce Under Surface and Overhead Irrigations

NASA Astrophysics Data System (ADS)

Bhalsod, G.; Chuang, Y. H.; Jeon, S.; Gui, W.; Li, H.; Guber, A.; Zhang, W.

2015-12-01

Pharmaceuticals and personal care products are being widely detected in wastewater and surface waters. As fresh water becomes scarcer, interests in using reclaimed water for crop irrigation is intensified. Since reclaimed waters often carry trace levels of pharmaceuticals, accumulation of pharmaceuticals in food crops could increase the risk of human exposure. This study aims to investigate uptake and accumulations of pharmaceuticals in greenhouse-grown lettuce under contrasting irrigation practices (i.e., overhead and surface irrigations). Lettuce was irrigated with water spiked with 11 commonly used pharmaceuticals (acetaminophen, caffeine, carbamazepine, sulfadiazine, sulfamethoxazole, carbadox, trimethoprim, lincomycin hydrochloride, oxytetracycline hydrochloride, monensin sodium, and tylosin). Weekly sampling of lettuce roots, shoots, and soils were continued for 5 weeks, and the samples were freeze dried, extracted for pharmaceuticals and analyzed by LC-MS/MS. Preliminary results indicate that higher concentrations of pharmaceuticals were found in overhead irrigated lettuce compared to surface irrigated lettuce. For carbamezapine, sulfadiazine, trimethoprim, oxytetracycline, and monensin sodium, their concentrations generally increased in lettuce shoots in the overhead treatment over time. However, acetaminophen was found at higher concentrations in both shoots and roots, indicating that acetaminophen can be easily transported in the plant system. This study provides insight on developing better strategies for using reclaimed water for crop irrigations, while minimizing the potential risks of pharmaceutical contamination of vegetables.

Can nitrate contaminated groundwater be remediated by optimizing flood irrigation rate with high nitrate water in a desert oasis using the WHCNS model?

PubMed

Liang, Hao; Qi, Zhiming; Hu, Kelin; Prasher, Shiv O; Zhang, Yuanpei

2016-10-01

Nitrate contamination of groundwater is an environmental concern in intensively cultivated desert oases where this polluted groundwater is in turn used as a major irrigation water resource. However, nitrate fluxes from root zone to groundwater are difficult to monitor in this complex system. The objectives of this study were to validate and apply the WHCNS (soil Water Heat Carbon Nitrogen Simulator) model to simulate water drainage and nitrate leaching under different irrigation and nitrogen (N) management practices, and to assess the utilization of groundwater nitrate as an approach to remediate nitrate contaminated groundwater while maintain crop yield. A two-year field experiment was conducted in a corn field irrigated with high nitrate groundwater (20 mg N L(-1)) in Alxa, Inner Mongolia, China. The experiment consisted of two irrigation treatments (Istd, standard, 750 mm per season; Icsv, conservation, 570 mm per season) factorially combined with two N fertilization treatments (Nstd, standard, 138 kg ha(-1); Ncsv, conservation, 92 kg ha(-1)). The validated results showed that the WHCNS model simulated values of crop dry matter, yield, soil water content and soil N concentration in soil profile all agreed well with the observed values. Compared to the standard water management (Istd), the simulated drainage and nitrate leaching decreased about 65% and 59%, respectively, under the conservation water management (Icsv). Nearly 55% of input N was lost by leaching under the IstdNstd and IstdNcsv treatments, compared to only 26% under the IcsvNstd and IcsvNcsv treatments. Simulations with more than 240 scenarios combing different levels of irrigation and fertilization indicated that irrigation was the main reason leading to the high risk of nitrate leaching, and the nitrate in irrigation groundwater can be best utilized without corn yield loss when the total irrigation was reduced from the current 750 mm to 491 mm. This reduced irrigation rate facilitated the use of approximately 42 kg N ha(-1) yr(-1) of nitrate from groundwater, which would gradually improve the groundwater quality. Future field studies on nitrate leaching in this area are suggested to investigate water and N dynamics under irrigation rates near 490 mm per season. Copyright © 2016 Elsevier Ltd. All rights reserved.

Direct observation of organic contaminant uptake, storage, and metabolism within plant roots.

PubMed

Wild, Edward; Dent, John; Thomas, Gareth O; Jones, Kevin C

2005-05-15

Two-photon excitation microscopy (TPEM) is used to visualize and track the uptake and movement of anthracene and phenanthrene from a contaminated growth medium into living unmodified roots of maize and wheat over a 56-day period. The degradation of anthracene was also directly observed within the cortex cells of both species. The power of this technique is that neither the plant nor the compound require altering (staining or sectioning) to visualize them, meaning they are in their natural form throughout the experiment. Initially both compounds bound to the epidermis along the zone of elongation, passing through the epidermal cells to reach the cortex within the root hair, and branching zones of the root. The PAHs entered the epidermis radially; however, once within the cortex cells this movement was dominated by slow lateral movement of both compounds toward the shoot. Highly focused "streams" of compound were observed to form over time; zones where phenanthrene concentrated extended up to 1500 microm in length over a 56-day period, for example, passing through several adjoining cells, and were detectable in cell walls and cell vacuoles. Radial movement was not observed to extend beyond the cortex cells to reach the vascular tissues of the plant. The longitudinal movement of both compounds was not observed to extend beyond the root base into the stem or vegetative parts of the plant. The lateral movement of both compounds within the cortex cells was dominated by movement within the cell walls, suggesting apoplastic flow through multiple cell walls, but with a low level of symplastic movement to transport compound into the cellular vacuoles. Degradation of anthracene to the partial breakdown products anthrone, anthraquinone, and hydroxyanthraquinone was observed directly in the zones of root elongation and branching. The technique and observations have important applications to the fields of agrochemistry and phytoremediation.

Comparative evaluation of apical extrusion of debris and irrigant with three rotary instruments using crown down technique - An in vitro study.

PubMed

Jindal, Rahul; Singh, Smita; Gupta, Siddharth; Jindal, Punita

2012-01-01

The purpose of this study was to evaluate and compare the apical extrusion of debris and irrigant using various rotary instruments with crown down technique in the instrumentation of root canals. Thirty freshly extracted human permanent straight rooted mandibular premolars with minimum root curvature of 0-10 ° were divided in three groups with 10 teeth in each group. Each group was instrumented using one of the three rotary instrumentation systems: Rotary Hero shapers, Rotary ProTaper and Rotary Mtwo. One ml of sterile water was used as an irrigant after using each instrument. Debris extruded was collected in pre weighed glass vials and the extruded irrigant was measured quantitatively by Myers and Montgomery method and was later evaporated. The weight of the dry extruded debris was calculated by comparing the pre and post instrumentation weight of glass vials for each group. Statistical analysis was done by using by a Kruskal-Wallis One-way ANOVA test. Statistical analysis showed that all the rotary instruments used in this study caused apical extrusion of debris and irrigant. A Statistically significant difference was observed with Rotary ProTaper and Rotary Mtwo groups when compared with Rotary Hero shapers. But no significant difference was observed between Rotary ProTaper and Rotary Mtwo groups. After instrumentation with different rotary instruments, Hero shapers showed a less apical extrusion of debris and irrigant.

Apical extrusion of debris and irrigants using hand and three rotary instrumentation systems– An in vitro study

PubMed Central

Madhusudhana, Koppolu; Mathew, Vinod Babu; Reddy, Nelaturi Madhusudhan

2010-01-01

Introduction: Sterilization of the root canal is a prime aim of successful endodontics. The cleaning and shaping of the canal is directed as achieving this goal. The extrusion of apical debris has a deleterious effect on the prognosis of root canal treatment. Several instrument designs and instrumentation techniques have been developed to prevent this. Materials and Methods: Forty caries free single rooted human mandibular premolar teeth were divided in four groups of ten teeth each. Teeth in each group were instrumented until the working length with rotary ProTaper, K3, Mtwo systems, and hand K-type stainless steel files. Debris and irrigant extruded from the apical foramen were collected into vials and the amounts were quantitatively determined. The data obtained were analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests. Results: The results show that all instrumentation techniques produced significant amount of extruded debris and irrigant. The engine-driven nickel-titanium systems showed less apical extrusion of debris and irrigant than manual technique. No statistically significant difference was found between the groups at [P > 0.05]. Maximum apical debris and irrigant extrusion was seen with K-file group and least in the Mtwo group. Conclusions: The use of rotary files and techniques to perform instrumentation does show less extrusion of the debris and irrigant from the apex. This can contribute to more successful endodontic therapy. PMID:22114427

Hydraulic characteristics of an underdrained irrigation circle, Muskegon County wastewater disposal system, Michigan

USGS Publications Warehouse

McDonald, M.G.

1980-01-01

Muskegon County, Michigan, disposes of wastewater by spray irrigating farmland on its waste-disposal site. Buried drains in the highly permeable unconfined aquifer at the site control the level of the water table. Hydraulic conductivity of the aquifer and drain-leakance, the reciprocal of resistance to flow into the drains, was determined at a representative irrigation circle while calibrating a model of the groundwater flow system. Hydraulic conductivity is 0.00055 m/sec, in the north zone of the circle, and 0.00039 m/sec in the south zone. Drain leakance -6 -6 is low in both zones: 2.9 x 10m/sec in the north and 9.5 x 10 m/sec in the south. Low drain leakance is responsible for waterlogging when irrigation rates are maintained at design levels. The capacity of the study circle to accept wastewater is 35 percent less than design capacity.

Irrigation and Nitrogen Regimes Promote the Use of Soil Water and Nitrate Nitrogen from Deep Soil Layers by Regulating Root Growth in Wheat

PubMed Central

Liu, Weixing; Ma, Geng; Wang, Chenyang; Wang, Jiarui; Lu, Hongfang; Li, Shasha; Feng, Wei; Xie, Yingxin; Ma, Dongyun; Kang, Guozhang

2018-01-01

Unreasonably high irrigation levels and excessive nitrogen (N) supplementation are common occurrences in the North China Plain that affect winter wheat production. Therefore, a 6-yr-long stationary field experiment was conducted to investigate the effects of irrigation and N regimes on root development and their relationship with soil water and N use in different soil layers. Compared to the non-irrigated treatment (W0), a single irrigation at jointing (W1) significantly increased yield by 3.6–45.6%. With increases in water (W2, a second irrigation at flowering), grain yield was significantly improved by 14.1–45.3% compared to the W1 treatments during the drier growing seasons (2010–2011, 2012–2013, and 2015–2016). However, under sufficient pre-sowing soil moisture conditions, grain yield was not increased, and water use efficiency (WUE) decreased significantly in the W2 treatments during normal precipitation seasons (2011–2012, 2013–2014, and 2014–2015). Irrigating the soil twice inhibited root growth into the deeper soil depth profiles and thus weakened the utilization of soil water and NO3-N from the deep soil layers. N applications increased yield by 19.1–64.5%, with a corresponding increase in WUE of 66.9–83.9% compared to the no-N treatment (N0). However, there was no further increase in grain yield and the WUE response when N rates exceeded 240 and 180 kg N ha−1, respectively. A N application rate of 240 kg ha−1 facilitated root growth in the deep soil layers, which was conducive to utilization of soil water and NO3-N and also in reducing the residual NO3-N. Correlation analysis indicated that the grain yield was significantly positively correlated with soil water storage (SWS) and nitrate nitrogen accumulation (SNA) prior to sowing. Therefore, N rates of 180–240 kg ha−1 with two irrigations can reduce the risk of yield loss that occurs due to reduced precipitation during the wheat growing seasons, while under better soil moisture conditions, a single irrigation at jointing was effective and more economical. PMID:29449850

May humic acids or mineral fertilisation mitigate arsenic mobility and availability to carrot plants (Daucus carota L.) in a volcanic soil polluted by As from irrigation water?

PubMed

Caporale, Antonio G; Adamo, Paola; Azam, Shah M G G; Rao, Maria A; Pigna, Massimo

2018-02-01

Carrot (Daucus carota L.) is a widely consumed root vegetable, whose growth and safety might be threatened by growing-medium arsenic (As) contamination. By this work, we evaluated the effects of humic acids from Leonardite and NPK mineral fertilisation on As mobility and availability to carrot plants grown for 60 days in a volcanic soil irrigated with As-contaminated water - representing the most common scenario occurring in As-affected Italian areas. As expected, the irrigation with As-contaminated water caused a serious toxic effect on plant growth and photosynthetic rate; the highest rate of As also inhibited soil enzymatic activity. In contrast, the organic and mineral fertilisation alleviated, at least partially, the toxicity of As, essentially by stimulating plant growth and promoting nutrient uptake. The mobility of As in the volcanic soil and thus its phytoavailability were differently affected by the organic and mineral fertilisers; the application of humic acids mitigated the availability of the contaminant, likely by its partial immobilisation on humic acid sorption sites - thus raising up the intrinsic anionic sorption capacity of the volcanic soil; the mineral fertilisation enhanced the mobility of As in soil, probably due to competition of P for the anionic sorption sites of the soil variable-charge minerals, very affine to available P. These findings hence suggest that a proper soil management of As-polluted volcanic soils and amendment by stable organic matter might mitigate the environmental risk of these soils, thus minimising the availability of As to biota. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fine root biomass, necromass and chemistry during seven years of elevated aluminium concentrations in the soil solution of a middle-aged Picea abies stand.

PubMed

Eldhuset, Toril D; Lange, Holger; de Wit, Helene A

2006-10-01

Toxic effects of aluminium (Al) on Picea abies (L.) Karst. (Norway spruce) trees are well documented in laboratory-scale experiments, but field-based evidence is scarce. This paper presents results on fine root growth and chemistry from a field manipulation experiment in a P. abies stand that was 45 years old when the experiment started in 1996. Different amounts of dissolved aluminium were added as AlCl3 by means of periodic irrigation during the growing season in the period 1997-2002. Potentially toxic concentrations of Al in the soil solution were obtained. Fine roots were studied from direct cores (1996) and sequential root ingrowth cores (1999, 2001, 2002) in the mineral soil (0-40 cm). We tested two hypotheses: (1) elevated concentration of Al in the root zone leads to significant changes in root biomass, partitioning into fine, coarse, living or dead fractions, and distribution with depth; (2) elevated Al concentration leads to a noticeable uptake of Al and reduced uptake of Ca and Mg; this results in Ca and Mg depletion in roots. Hypothesis 1 was only marginally supported, as just a few significant treatment effects on biomass were found. Hypothesis 2 was supported in part; Al addition led to increased root concentrations of Al in 1999 and 2002 and reduced Mg/Al in 1999. Comparison of roots from subsequent root samplings showed a decrease in Al and S over time. The results illustrated that 7 years of elevated Al(tot) concentrations in the soil solution up to 200 microM are not likely to affect root growth. We also discuss possible improvements of the experimental approach.

Debris remaining in the apical third of root canals after chemomechanical preparation by using sodium hypochlorite and glyde: an in vivo study.

PubMed

Cruz, Alvaro; Vera, Jorge; Gascón, Gerardo; Palafox-Sánchez, Claudia A; Amezcua, Octavio; Mercado, Gabriela

2014-09-01

During chemomechanical instrumentation, several liquid or paste substances are used to ease the action of the files and to eliminate debris and the smear layer. The aim of this study was to evaluate whether the use of a paste containing EDTA during cleaning and shaping of the root canal helps to eliminate debris. Twenty root canals in dog teeth were instrumented by a crown-down technique by using nickel-titanium rotary files. In 10 root canals (group A), sodium hypochlorite was used during instrumentation, followed by a final irrigation with 17% liquid EDTA. In another 10 canals (group B), sodium hypochlorite was again used as the irrigating solution, but Glyde File Prep paste was used with every instrument, and a final irrigation with EDTA was also carried out. Two additional teeth were used as positive and 2 as negative controls. The jaws were prepared for histologic evaluation. In group A where Glyde was not used during cleaning and shaping, little or no debris was found in the apical third of the instrumented root canals; however; in group B in which Glyde File Prep paste was used during chemomechanical instrumentation, moderate to high accumulation of debris was observed in the apical third. The use of Glyde File Prep paste during rotary mechanical instrumentation favors the accumulation of debris in the apical third of the root canals. Irrigation with NaOCl and a final flush with EDTA by means of a small-gauge needle with simultaneous aspiration led to less accumulation of debris than in the Glyde File Prep group (P < .05). Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

A Site-sPecific Agricultural water Requirement and footprint Estimator (SPARE:WATER 1.0)

NASA Astrophysics Data System (ADS)

Multsch, S.; Al-Rumaikhani, Y. A.; Frede, H.-G.; Breuer, L.

2013-07-01

The agricultural water footprint addresses the quantification of water consumption in agriculture, whereby three types of water to grow crops are considered, namely green water (consumed rainfall), blue water (irrigation from surface or groundwater) and grey water (water needed to dilute pollutants). By considering site-specific properties when calculating the crop water footprint, this methodology can be used to support decision making in the agricultural sector on local to regional scale. We therefore developed the spatial decision support system SPARE:WATER that allows us to quantify green, blue and grey water footprints on regional scale. SPARE:WATER is programmed in VB.NET, with geographic information system functionality implemented by the MapWinGIS library. Water requirements and water footprints are assessed on a grid basis and can then be aggregated for spatial entities such as political boundaries, catchments or irrigation districts. We assume inefficient irrigation methods rather than optimal conditions to account for irrigation methods with efficiencies other than 100%. Furthermore, grey water is defined as the water needed to leach out salt from the rooting zone in order to maintain soil quality, an important management task in irrigation agriculture. Apart from a thorough representation of the modelling concept, we provide a proof of concept where we assess the agricultural water footprint of Saudi Arabia. The entire water footprint is 17.0 km3 yr-1 for 2008, with a blue water dominance of 86%. Using SPARE:WATER we are able to delineate regional hot spots as well as crop types with large water footprints, e.g. sesame or dates. Results differ from previous studies of national-scale resolution, underlining the need for regional estimation of crop water footprints.

Determination of threshold value of soil water content for field and vegetable plants with lysimeter measurements

NASA Astrophysics Data System (ADS)

Knoblauch, S.

2009-04-01

Both the potential water consumption of plants and their ability to withdraw soil water are necessary in order to estimate actual evapotranspiration and to predict irrigation timing and amount. In relating to root water uptake the threshold value at which plants reducing evapotranspiration is an important parameter. Since transpiration is linearly correlated to dry matter production, under the condition that the AET/PET-Quotient is smaller than 1.0 (de Wit 1958, Tanner & Sinclair 1983), the dry matter production begins to decline too. Plants respond to drought with biochemical, physiological and morphological modifications in order to avoid damages, for instance by increasing the root water uptake. The objective of the study is to determine threshold values of soil water content and pressure head respectively for different field and vegetable plants with lysimeter measurements and to derive so called reduction functions. Both parameter, potenzial water demand in several growth stages and threshold value of soil water content or pressure head can be determined with weighable field lysimeter. The threshold value is reached, when the evapotranspiration under natural rainfall condition (AET) drop clearly (0.8 PET) below the value under well watered condition (PET). Basis for the presented results is the lysimeter plant Buttelstedt of the Thuringian State Institute of Agriculture. It consist of two lysimeter cellars, each with two weighable monolithic lysimeters. The lysimeter are 2.5 m deep with a surface area of 2 m2 to allow a non-restrictive root growth and to arrange a representative number of plants. The weighing accuracy amounts to 0.05 mm. The percolating water is collected by ceramic suction cups with suction up to 0.3 MPa at a depth of 2.3 m. The soil water content is measured by using neutron probe. One of the two lysimeter cellars represents the will irrigated, the other one the non irrigated and/or reduced irrigated part of field. The soil is a Haplic Phaeozem with silt-loamy texture developed from loess (water content at wilting point amounts between 0.167 and 0.270 cm3/cm3 and at field capacity (0.03 MPa) between 0.286 and 0.342 cm3/cm3). The mean annual temperature is 8.2°C and the mean annual precipitation is 550 mm. Results are as follows: Winter wheat begins to reduce evapotranspiration when the water content in the root zone to a depth of 2.0 m is smaller than 25 % of the available water holding capacity (AWC). That is equal to an amount of soil water of 171 mm. The threshold value of potatoes is 40 % of the AWC to a rooting depth of 0.6 m (49 mm soil water amount). The corresponding value for cabbage is 40 % of the AWC relating to a rooting depth of 1.2 m, for cauli flower 60 % of the AWC relating to a depth of 1.0 m and for onion 80 % of the AWC to a rooting depth of 0.3 m (90, 50 and 5 mm soil water amount). Nevertheless onion attain a maximum rooting depth of 0.9 m. The maximum rooting depths of winter wheat, potatoes, cabbage and cawli flower are 2.0, 1.0, 1.5 und 1.5 m. The date on which the threshold is reached is different, for winter wheat and cabbage just before harvest and for onion in a few days after 8-leaf-stage. However, it is assumed that these values are also the influence of weather reflect, particulary with regard to the transpiration demand of the atmosphere and the amount of rain fall during earlier growth stages which can prefer the development of adaptation mechanism. Although there are great differences between the plant species concerning root water uptake to avoid a decline of biomass production due to drought.

From files to SAF: 3D endodontic treatment is possible at last.

PubMed

Metzger, Zvi

2011-01-01

3D cleaning, shaping and obturation of root canals has always been the desired goal of endodontic treatment which in many cases is difficult to attain. The introduction of NiTi rotary files made a major change in endodontic practice, making treatment easier, safer and faster. Nevertheless, after 16 years of intensive development, most of these instruments still share several drawbacks, the major one being the inability to three-dimensionally clean and shape oval root canals. The Self-Adjusting File (SAF) System was designed to overcome many of the current drawbacks of rotary file systems. It is based on a hollow, highly compressible file that adapts itself three-dimensionally to the shape of a given root canal, including its cross section. The file is operated with vibratory in-and-out motion, with continuous irrigation delivered by a peristaltic pump through the hollow file. A uniform layer of dentin is removed from the whole circumference of the root canal, thus achieving the main goals of root canal treatment while preserving the remaining root dentin. The 3D scrubbing effect of the file, combined with the always fresh irrigant, result in unprecedentedly clean canals which facilitate in turn better obturation. More effective disinfection of flat-oval root canals is another goal which is simultaneously attained. The safety of the root-canal treatment is also greatly enhanced by the high mechanical stability of the SAF and by using a new concept of no-pressure irrigation. The SAF System gets the operator much closer to the long-desired goal of 3D root-canal treatment.

Root-zone temperatures affect phenology of bud break, flower cluster development, shoot extension growth and gas exchange of 'Braeburn' (Malus domestica) apple trees.

PubMed

Greer, Dennis H; Wünsche, Jens N; Norling, Cara L; Wiggins, Harry N

2006-01-01

We investigated the effects of root-zone temperature on bud break, flowering, shoot growth and gas exchange of potted mature apple (Malus domestica (Borkh.)) trees with undisturbed roots. Soil respiration was also determined. Potted 'Braeburn' apple trees on M.9 rootstock were grown for 70 days in a constant day/night temperature regime (25/18 degrees C) and one of three constant root-zone temperatures (7, 15 and 25 degrees C). Both the proportion and timing of bud break were significantly enhanced as root-zone temperature increased. Rate of floral cluster opening was also markedly increased with increasing root-zone temperature. Shoot length increased but shoot girth growth declined as root-zone temperatures increased. Soil respiration and leaf photosynthesis generally increased as root-zone temperatures increased. Results indicate that apple trees growing in regions where root zone temperatures are < or = 15 degrees C have delayed bud break and up to 20% fewer clusters than apple trees exposed to root zone temperatures of > or = 15 degrees C. The effect of root-zone temperature on shoot performance may be mediated through the mobilization of root reserves, although the role of phytohormones cannot be discounted. Variation in leaf photosynthesis across the temperature treatments was inadequately explained by stomatal conductance. Given that root growth increases with increasing temperature, changes in sink activity induced by the root-zone temperature treatments provide a possible explanation for the non-stomatal effect on photosynthesis. Irrespective of underlying mechanisms, root-zone temperatures influence bud break and flowering in apple trees.

Effects of Diode Laser, Gaseous Ozone, and Medical Dressings on Enterococcus faecalis Biofilms in the Root Canal Ex Vivo

PubMed Central

Vlassakidis, Alexander; Niepel, Mediha; Hoedke, Daniela; Schulze, Julia; Neumann, Konrad; Moter, Annette; Noetzel, Jörn

2017-01-01

The objective was to compare the antibacterial effects of adjunctive disinfection using diode laser and gaseous ozone compared to the medical dressings calcium hydroxide (Ca(OH)2) and chlorhexidine gel (CHX-Gel) on Enterococcus faecalis biofilms in human root canals ex vivo. Root canals of 180 human extracted teeth were infected by E. faecalis and divided into 3 main groups (G): G1, control; G2, instrumentation and irrigation using 0.9% NaCl; G3, instrumentation and irrigation using 1% NaOCl. In each main group, the following treatments were applied: gaseous ozone, diode laser, and medical dressings of Ca(OH)2 or CHX-Gel for 7 days (n = 15). Reduction of colony forming units (CFUs) inside the root canal of planktons and frequencies of adherent bacteria after treatment were calculated. Bacterial reduction was significantly affected by the irrigation protocol (p < 0.0005) and the disinfection method (p < 0.0005), and a significant interaction between both factors could be observed (p < 0.0005; ANOVA). In G3 (instrumentation using 1% NaOCl), no significant effect of disinfection methods could be demonstrated on planktonic bacteria (p = 0.062; ANOVA) and frequencies of adherent bacteria (p > 0.05; chi-square test). Instrumentation and irrigation using NaOCl combined with ozone or laser application resulted in comparable bacterial reduction on E. faecalis to the application of medical dressings. PMID:28567421

Efficacy of new irrigating solution on smear layer removal in apical third of root canal: A scanning electron microscope study.

PubMed

Patil, Priyanka Himmatrao; Gulve, Meenal Nitin; Kolhe, Swapnil Janardan; Samuel, Roshan Mathew; Aher, Gayatri Balasaheb

2018-01-01

The aim of this in vitro study is to evaluate and compare the smear layer removal efficacy of etidronic acid-based irrigating solution with others in the apical third of the root canal. Forty human single-rooted mandibular premolar teeth were taken and decoronated to standardize the canal length. After biomechanical preparation, teeth were randomly divided into four groups ( n = 10) and the final irrigation was carried out with tested irrigants. Group I: normal saline (negative control); Group II: 5.25% sodium hypochlorite (NaOCl) with surfactant and 17% ethylenediaminetetraacetic acid (EDTA) with surfactant; Group III: freshly mixed BioPure MTAD; and Group IV: freshly mixed Chloroquick solution. The teeth were split into two halves and observed under a scanning electron microscope to analyze the amount of smear layer present. Data were analyzed using the Kruskal-Wallis test and Mann-Whitney test. Group II (5.25% NaOCl with surfactant followed by 17% EDTA with surfactant) showed least smear layer scores (1.1 ± 0.3162). This was followed by Group III (MTAD) (2.2 ± 0.4216) and then Group IV (Chloroquick) (2.4 ± 0.5164). Sequential use of 5.25% NaOCl with surfactant and 17% EDTA with surfactant was found to be the most efficient than MTAD and Chloroquick in the removal of smear layer in the apical third of root canal.

Effectiveness of Three Different Irrigants - 17% Ethylenediaminetetraacetic Acid, Q-MIX, and Phytic Acid in Smear Layer Removal: A Comparative Scanning Electron Microscope Study.

PubMed

Jagzap, Janhavi Balasaheb; Patil, Sanjay S; Gade, Vandana Jaykumar; Chandhok, Deepika J; Upagade, Madhura A; Thakur, Deepa A

2017-01-01

Removal of smear layer from the root canal walls is important for long-standing endodontic success. The aim of this study is to evaluate and compare smear layer removing ability among 17% ethylenediaminetetraacetic acid (EDTA), Q-MIX, and phytic acid by scanning electron microscopy (SEM). This in-vitro experimental study assessed smear layer removal using three different irrigants. Thirty single-rooted freshly extracted human permanent premolars were collected, disinfected, and decoronated to a standardized root length of 13 mm. Root canals were cleaned and shaped till F2 universal rotary protaper at working length 1 mm short of the apex. They were randomly divided into three groups, and final irrigation was done accordingly. Group 1 ( n = 10): with 1 ml of 17% EDTA, Group 2 ( n = 10): with 1 ml of Q-MIX, Group 3 ( n = 10): with 1 ml of phytic acid. Samples were then longitudinally sectioned and evaluated under SEM at coronal, middle, and apical levels. Two-way analysis of variance and Tukey's post hoc test were performed. The level of significance was set at 0.05. Smear layer removing ability among irrigants and sections in descending order: 17 EDTA > Q-MIX > phytic acid; coronal > middle > apical. 17% EDTA showed better and promising results followed by Q-MIX and then phytic acid.

Soft chelating irrigation protocol optimizes bonding quality of Resilon/Epiphany root fillings.

PubMed

De-Deus, Gustavo; Namen, Fátima; Galan, João; Zehnder, Matthias

2008-06-01

This study was designed to test the impact of either a strong (MTAD) or a soft (1-hydroxyethylidene-1, 1-bisphosphonate [HEPB]) chelating solution on the bond strength of Resilon/Epiphany root fillings. Both 17% EDTA and the omission of a chelator in the irrigation protocol were used as reference treatments. Forty extracted human upper lateral incisors were prepared using different irrigation protocols (n = 10): G1: NaOCl, G2: NaOCl + 17% EDTA, G3: NaOCl + BioPure MTAD (Dentsply/Tulsa, Tulsa, OK), and G4: NaOCl + 18% HEPB. The teeth were obturated and then prepared for micropush-out assessment using root slices of 1 mm thickness. Loading was performed on a universal testing machine at a speed of 0.5 mm/min. One-way analysis of variance and Tukey multiple comparisons were used to compare the results among the experimental groups. EDTA- and MTAD-treated samples revealed intermediate bond strength (0.3-3.6 MPa). The lowest bond strengths were achieved in NaOCl-treated samples (0.3-1.2 MPa, p < 0.05). The highest bond strength was reached in the HEBP-treated samples (3.1-6.1 MPa, p < 0.05). Under the present in vitro conditions, the soft chelating irrigation protocol (18% HEBP) optimized the bonding quality of Resilon/Epiphany (Resilon Research LLC, Madison, CT) root fillings.

Measurement of pressure and flow rates during irrigation of a root canal ex vivo with three endodontic needles.

PubMed

Boutsioukis, C; Lambrianidis, T; Kastrinakis, E; Bekiaroglou, P

2007-07-01

To monitor ex vivo intra-canal irrigation with three endodontic needles (25, 27 and 30 gauge) and compare them in terms of irrigant flow rate, intra-barrel pressure, duration of irrigation and volume of irrigant delivered. A testing system was constructed to allow measurement of selected variables with pressure and displacement transducers during ex vivo intra-canal irrigation with a syringe and three different needles (groups A, B, C) into a prepared root canal. Ten specialist endodontists performed the irrigation procedure. Each operator performed ten procedures with each needle. Data recorded by the transducers were analysed using Friedman's test, Wilcoxon Signed Rank test, Mann-Whitney U-test and Kendall's T(b) test. The level of significance was set to 95%. Significant differences were detected among the three needles for most variables. Duration of delivery and flow rates significantly decreased as the needle diameter increased, whilst pressure increased up to 400-550 kPa. Gender of the operator had a significant impact on the results. Experience of the operators (years) were negatively correlated to volume of irrigant (all groups), to the duration of delivery (groups A, B) and to the average flow rate (group A). Finer diameter needles require increased effort to deliver the irrigant and result in higher intra-barrel pressure. The syringe and needles used tolerated the pressure developed. Irrigant flow rate should be considered as a factor directly influencing flow beyond the needle. Wide variations of flow rate were observed among operators. Syringe irrigation appears difficult to standardize and control.

Biomolecular Characterization of Diazotrophs Isolated from the Tropical Soil in Malaysia

PubMed Central

Naher, Umme Aminun; Othman, Radziah; Latif, Mohammad Abdul; Panhwar, Qurban Ali; Amaddin, Puteri Aminatulhawa Megat; Shamsuddin, Zulkifli H

2013-01-01

This study was conducted to evaluate selected biomolecular characteristics of rice root-associated diazotrophs isolated from the Tanjong Karang rice irrigation project area of Malaysia. Soil and rice plant samples were collected from seven soil series belonging to order Inceptisol (USDA soil taxonomy). A total of 38 diazotrophs were isolated using a nitrogen-free medium. The biochemical properties of the isolated bacteria, such as nitrogenase activity, indoleacetic acid (IAA) production and sugar utilization, were measured. According to a cluster analysis of Jaccard’s similarity coefficients, the genetic similarities among the isolated diazotrophs ranged from 10% to 100%. A dendogram constructed using the unweighted pair-group method with arithmetic mean (UPGMA) showed that the isolated diazotrophs clustered into 12 groups. The genomic DNA rep-PCR data were subjected to a principal component analysis, and the first four principal components (PC) accounted for 52.46% of the total variation among the 38 diazotrophs. The 10 diazotrophs that tested highly positive in the acetylene reduction assay (ARA) were identified as Bacillus spp. (9 diazotrophs) and Burkholderia sp. (Sb16) using the partial 16S rRNA gene sequence analysis. In the analysis of the biochemical characteristics, three principal components were accounted for approximately 85% of the total variation among the identified diazotrophs. The examination of root colonization using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) proved that two of the isolated diazotrophs (Sb16 and Sb26) were able to colonize the surface and interior of rice roots and fixed 22%–24% of the total tissue nitrogen from the atmosphere. In general, the tropical soils (Inceptisols) of the Tanjong Karang rice irrigation project area in Malaysia harbor a diverse group of diazotrophs that exhibit a large variation of biomolecular characteristics. PMID:23999588

Development of Strategies for Sustainable Irrigation Water Management in Russia

NASA Astrophysics Data System (ADS)

Zeyliger, Anatoly; Ermolaeva, Olga

2013-04-01

During 1960 - 1990 years irrigated areas in Russia have increased rapidly, helping to boost agricultural output. Although the impressive achievements of irrigation in this period its large experience indicates problems and failures of irrigation water management. In addition to large water use and low irrigation water efficiency, environmental concerns (excessive water depletion, water quality reduction, water logging, soil degradation) are usually considered like the most significant problem of the irrigation sector. Despite of considerable shrinking of irrigated areas in Russia and decreasing of water withdrawal for irrigation purposes during two last decades a degradation of environment as well as degradation of soil and water resources in irrigated areas was prolonged and will probably continue if current irrigation practices are maintained. Nowadays, in different regions of Russia there are societal demand to restore agricultural irrigation in Russia as answer to challenges from climate pattern changes and degradation of land & water resources. In the respect of these demands there is a need to develop strategies for sustainability of agricultural irrigation in Russia that should be based on three main societal objectives: costeffective use of water in irrigated agriculture at farm level, and satisfactory preserving the natural environment. Therefore sustainable irrigation water management is not only an objective at farm level but also an overall goal at the local and regional as well. A way to achieve sustainability in irrigation water management is to solve the local conflicts arising from the interactions between water use at irrigation areas and surrounding environment. Thus should be based on the development of irrigation framework program including on the irrigation water management issues, policies & decisions making at federal and regional levels should be based on the indicators of environment & irrigation water efficiency monitoring promoting the use of the appropriate irrigation technologies confined to a field scale and local environmental conditions. In presented contribution a case studies of large and small irrigation schemes based on sprinklers at Saratov Region will be discussed. Analyze is focused on the identification of main causes of groundwater logging, following soil salinization and impact to surrounding environment at irrigation areas. This analyze is based on plot and field scales experimentations as well as time series about 40 years long monitoring of ground water and soils. Main conclusion from this analyze accuses current irrigation practice at this region using high irrigation dozes & intensities as well as uniformity of water application within the irrigated perimeter promoting chain of processes starting by ponding of applied water at mezodepression of soil surface, preferential flow through out macropores-cracks, wormholes, or decayed root channels and groundwater rising. Special attention is done to simulate relationships between uniform technology of water application by sprinkler and spatial nonuniformity of moisture storage (zoning of high soil moisture in depressions) in soil and as consequence of infiltration capacity. Technological alternative aimed at reducing these problems is analysed by the use of SWAP model application to uniform and nonuniform irrigation water applications. Model results indicate that use nonuniform water application technology is increasing an irrigation efficiency, increasing yield and stopping rising of groundwater. ACKNOWLEDGMENTS. This study was financially supported by FP6 DESIRE project 037046

A Comparison of Satellite Data-Based Drought Indicators in Detecting the 2012 Drought in the Southeastern US

NASA Technical Reports Server (NTRS)

Yagci, Ali Levent; Santanello, Joseph A.; Rodell, Matthew; Deng, Meixia; Di, Liping

2018-01-01

The drought of 2012 in the North America devastated agricultural crops and pastures, further damaging agriculture and livestock industries and leading to great losses in the economy. The drought maps of the United States Drought Monitor (USDM) and various drought monitoring techniques based on the data collected by the satellites orbiting in space such as the Gravity Recovery and Climate Experiment (GRACE) and the Moderate Resolution Imaging Spectroradiometer (MODIS) are inter-compared during the 2012 drought conditions in the southeastern United States. The results indicated that spatial extent of drought reported by USDM were in general agreement with those reported by the MODIS-based drought maps. GRACE-based drought maps suggested that the southeastern US experienced widespread decline in surface and root-zone soil moisture and groundwater resources. Disagreements among all drought indicators were observed over irrigated areas, especially in Lower Mississippi region where agriculture is mainly irrigated. Besides, we demonstrated that time lag of vegetation response to changes in soil moisture and groundwater partly contributed to these disagreements, as well.

Phosphorus and other soil components in a dairy effluent sprayfield within the central Florida Ridge.

PubMed

Woodard, Kenneth R; Sollenberger, Lynn E; Sweat, Lewin A; Graetz, Donald A; Nair, Vimala D; Rymph, Stuart J; Walker, Leighton; Joo, Yongsung

2007-01-01

There is concern that P from dairy effluent sprayfields will leach into groundwater beneath Suwannee River basins in northern Florida. Our purpose was to describe the effects of dairy effluent irrigation on the movement of soil P and other nutrients within the upper soil profile of a sprayfield over three 12-mo cycles (April 1998-March 2001). Effluent P rates of 70, 110, and 165 kg ha(-1) cycle(-1) were applied to forages that were grown year-round. The soil is a deep, excessively drained sand (thermic, uncoated Typic Quartzipsamment). Mean P concentration in soil water below the rooting zone (152-cm depth) was < or = 0.1 mg L(-1) during 11 3-mo periods. Mehlich-1-extractable (M1) P, Al, and Ca in the topsoil increased over time but did not change in subsoil depths of 25 to 51, 51 to 71, 71 to 97, and 97 to 122 cm. Topsoil Ca increased as effluent rate increased. High Ca levels were found in dairy effluent (avg.: 305 mg L(-1)) and supplemental irrigation water (avg.: 145 mg L(-1)) which likely played a role in retaining P in the topsoil. An effect of effluent rate on P and Al concentrations in the topsoil was not detected, probably due to large and variable quantities present at project initiation. The P retention capacity (i.e., Al plus Fe) increased in the topsoil because Al increased. Dairy effluent contained Al (avg.: 31 mg L(-1)). Phosphorus saturation ratio (PSR) increased over time in the topsoil but not in subsoil layers. Regardless of effluent rate, the P retention capacity and PSR of subsoil, which contained 119 to 229 mg kg(-1) of Al, should be taken into account when assessing the risk of P moving below the rooting zone of most forage crops.

Determination of Root Canal Cleanliness by Different Irrigation Methods and Morphometric Analysis of Apical Third.

PubMed

Seixas, Fábio Heredia; Estrela, Carlos; Bueno, Mike Reis; Sousa-Neto, Manoel Damião; Pécora, Jesus Djalma

2015-06-01

The aim of this study was to determine the root canal area before and after the instrumentation 1 mm short of the apical foramen by clinical and cone beam computed tomography (CBCT) methods, and to evaluate the cleanliness of the apical region in mesiodistal flattened teeth by using optical microscopy. Forty-two human single-canal mandibular incisors were instrumented using the Free Tip Preparation technique up to three, four or five instruments from the initial. Cone beam computed tomography scans were acquired of the samples before and after root canal preparation (RCP). Irrigation was performed by conventional or hydrodynamic means, using 2.5% sodium hypochlorite. The samples were prepared for observation under an optical microscope. Images were digitally obtained, analyzed and the results were submitted to statistical analysis (two-way ANOVA complemented by Bonferroni's post-test). There was no significant difference between the studied anatomical areas with both CBCT and clinical methods. There were no differences between irrigation methods. It was verified differences between instrumentation techniques. Instrumentation with four instruments from the initial instrument determined a significant increase in the contact area when compared to preparation with three instruments, but RCP with 5 instruments did not result in a better cleanliness. The analysis with CBCT was not capable to determine the precise shape of surgical apical area comparing to the clinical method. Both the conventional and hydrodynamic irrigation techniques were not able to promote root canals debris-free. The instruments action in root canal walls was proportional to the number of instruments used from the initial apical instrument.

Expression of ABA synthesis and metabolism genes under different irrigation strategies and atmospheric VPDs is associated with stomatal conductance in grapevine (Vitis vinifera L. cv Cabernet Sauvignon).

PubMed

Speirs, Jim; Binney, Allan; Collins, Marisa; Edwards, Everard; Loveys, Brian

2013-04-01

The influence of different levels of irrigation and of variation in atmospheric vapour pressure deficit (VPD) on the synthesis, metabolism, and transport of abscisic acid (ABA) and the effects on stomatal conductance were examined in field-grown Cabernet Sauvignon grapevines. Xylem sap, leaf tissue, and root tissue were collected at regular intervals during two seasons in conjunction with measurements of leaf water potential (Ψleaf) and stomatal conductance (gs). The different irrigation levels significantly altered the Ψleaf and gs of the vines across both seasons. ABA abundance in the xylem sap was correlated with gs. The expression of genes associated with ABA synthesis, NCED1 and NCED2, was higher in the roots than in the leaves throughout and highest in the roots in mid January, a time when soil moisture declined and VPD was at its highest. Their expression in roots was also inversely related to the levels of irrigation and correlated with ABA abundance in the roots, xylem sap, and leaves. Three genes encoding ABA 8'-hydroxylases were isolated and their identities confirmed by expression in yeast cells. The expression of one of these, Hyd1, was elevated in leaves when VPD was below 2.0-2.5 kPa and minimal at higher VPD levels. The results provide evidence that ABA plays an important role in linking stomatal response to soil moisture status and that changes in ABA catabolism at or near its site of action allows optimization of gas exchange to current environmental conditions.

Monitoring the effectiveness of root canal procedures on endotoxin levels found in teeth with chronic apical periodontitis

PubMed Central

MARINHO, Ariane Cassia Salustiano; MARTINHO, Frederico Canato; ZAIA, Alexandre Augusto; FERRAZ, Caio Cezar Randi; GOMES, Brenda Paula Figueiredo de Almeida

2014-01-01

Objective: The aim of this study was to monitor the effectiveness of root canal procedures by using different irrigants and intracanal medication on endotoxin levels found in root canals of teeth with chronic apical periodontitis. Material and Methods: Thirty root canals of teeth with pulpal necrosis associated with periapical lesions were selected and randomly divided into groups according to the irrigants used: GI - 2.5% NaOCl, GII - 2% chlorhexidine (CHX) gel, and GIII - saline solution (SS) (all, n=10). Samples were collected with sterile/apyrogenic paper points before (S1) and after root canal instrumentation (S2), after use of 17% ethylenediaminetetraacetic acid (EDTA) (S3), and after 30 days of intracanal medication (Ca(OH)2+SS) (S4). A turbidimetric kinetic Limulus Amebocyte Lysate assay was used for endotoxin measurement. Results: Endotoxins were detected in 100% of the root canals investigated (30/30), with a median value of 18.70 EU/mL. After S2, significant median percentage reduction was observed in all groups, irrespective of the irrigant tested: 2.5% NaOCl (99.65%) (GI), 2% CHX (94.27%) (GII), and SS (96.79%) (GIII) (all p<0.05). Root canal rinse with 17% EDTA (S3) for a 3-minute period failed to decrease endotoxin levels in GI and a slight decrease was observed in GII (59%) and GIII (61.1%) (all p>0.05). Intracanal medication for 30 days was able to significantly reduce residual endotoxins: 2.5% NaOCl (90%) (GI), 2% CHX (88.8%) (GII), and SS (85.7%) (GIII, p<0.05). No differences were found in the endotoxin reduction when comparing s2 and s4 treatment groups. Conclusion: Our findings demonstrated the effectiveness of the mechanical action of the instruments along with the flow and backflow of irrigant enduring root canal instrumentation for the endotoxin removal from root canals of teeth with chronic apical periodontitis. Moreover, the use of intracanal medication for 30 days contributed for an improvement of endotoxin reduction. PMID:25075670

Comparison of apical extrusion of sodium hypochlorite using 4 different root canal irrigation techniques.

PubMed

İriboz, Emre; Bayraktar, Koral; Türkaydın, Dilek; Tarçın, Bilge

2015-03-01

We compared the apical extrusion of sodium hypochlorite delivered with a 27-G needle, self-adjusting file (SAF), passive ultrasonic irrigation, or the EndoVac system (SybronEndo, Orange, CA) during the instrumentation and final irrigation of root canals. Matched paired single-canal teeth were divided into 8 groups. The experimental groups were needle irrigation size #30 (NI30) and #50 (NI50), SAF size #30 (SAF30) and #50 (SAF50), passive ultrasonic irrigation size #30 (PUI30) and #50 (PUI50), and EndoVac size #30 (EV30) and #50 (EV50). Teeth were embedded in 0.2% agarose gel (pH = 7.4) containing 1 mL 0.1% m-Cresol purple (Sigma-Aldrich, St Louis, MO), which changes color at a pH level of 9.0. Root canals were irrigated with sodium hypochlorite and EDTA using 4 different techniques, and the amount of irrigant was controlled. Standardized digital photographs were taken 20 minutes after the first irrigant was used and were analyzed to determine the amount of extrusion (expressed as a percentage of total pixels). The amounts of apical extrusion obtained in the NI30, NI50, SAF30, SAF50, PUI30, PUI50, EV30, and EV50 groups were 30% (3/10), 50% (5/10), 20% (2/10), 70% (7/10), 40% (4/10), 40% (4/10), 10% (1/10), and 10% (1/10), respectively. The overall extrusion frequency, regardless of the apical preparation size, was 40% (8/20) for needle, 45% (9/20) for SAF, 40% (8/20) for ultrasonic irrigation, and 10% (2/20) for EndoVac. Although the SAF group showed more extrusion, the percentage of pixels was significantly higher in the needle irrigation group (P < .01). The EndoVac group showed significantly lower extrusion values than the other techniques in terms of the number of teeth and pixels (P < .05 and P < .01, respectively). The risk of apical extrusion is significantly lower with the EndoVac in comparison with the 3 other techniques. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Implications for water use of a shift from annual to perennial crops - A stochastic modelling approach based on a trait meta-analysis

NASA Astrophysics Data System (ADS)

Vico, Giulia; Brunsell, Nathaniel

2017-04-01

The projected population growth and changes in climate and dietary habits will further increase the pressure on water resources globally. Within precision farming, a host of technical solutions has been developed to reduce water consumption for agricultural uses. The next frontier for a more sustainable agriculture is the combination of reduced water requirements with enhanced ecosystem services. Currently, staple grains are obtained from annuals crops. A shift from annual to perennial crops has been suggested as a way to enhance ecosystem services. In fact, perennial plants, with their continuous soil cover and the higher allocation of resources to the below ground, contribute to the reduction of soil erosion and nutrient losses, while enhancing carbon sequestration in the root zone. Nevertheless, the net effect of a shift to perennial crops on water use for agriculture is still unknown, despite its relevance for the sustainability of such a shift. We explore here the implications for water management at the field- to farm-scale of a shift from annual to perennial crops, under rainfed and irrigated agriculture. A probabilistic description of the soil water balance and crop development is employed to quantify water requirements and yields and their inter-annual variability, as a function of rainfall patterns, soil and crop features. Optimal irrigation strategies are thus defined in terms of maximization of yield and minimization of required irrigation volumes and their inter-annual variability. The probabilistic model is parameterized based on an extensive meta-analysis of traits of co-generic annual and perennial species to explore the consequences for water requirements of shifting from annual to perennial crops under current and future climates. We show that the larger and more developed roots of perennial crops may allow a better exploitation of soil water resources and a reduction of yield variability with respect to annual species. At the same time, perennial crops are larger and may require adequate water supply for longer periods, thus leading to higher water requirements. Furthermore, they lead to lower yields per unit area, thus requiring irrigation of larger areas.

Root canal obturation: experimental study on the thermafil system related to different irrigation protocols

PubMed Central

Migliau, Guido; Sofan, Afrah Ali Abdullah; Sofan, Eshrak Ali Abdullah; Cosma, Salvatore; Eramo, Stefano; Gallottini, Livio

2014-01-01

Summary Aim The aim of this study was to stress the ability of a specific obturation technique (thermafil technique) to seal root canal system in presence or absence of smear layer. Methodology Sixteen monoradicular teeth, extracted for periodontal reasons, were collected for this study. All specimens were prepared with nickel-titanium rotary files, and then divided into two groups: for each group was applied a different kind of irrigation method, verifying the effectiveness in removing the smear layer, thus rendering the dentinal tubules more permeable for penetration of softened gutta-percha. Thermafil system was used to fill the root canals, and then all the specimens were observed under scanning electron microscope (SEM). Results The results showed that the Group which followed irrigation only with sodium hypochlorite exhibited significantly less gutta-percha tags when compared to the second Group, which was irrigated with sodium hypochlorite and EDTA. Conclusion The thermafil systems have a very good quality of compression and fluency that permit to gain a good seal of endodontic space; furthermore it allows the penetration of gutta-percha with the formation of numerous of gutta-percha tags inside the dentinal tubules above all when smear layer is reduced or eliminated. PMID:25506413

In vivo efficacy of three different endodontic irrigation systems for irrigant delivery to working length of mesial canals of mandibular molars.

PubMed

Munoz, Hugo Roberto; Camacho-Cuadra, Karla

2012-04-01

Many in vitro studies have debated over the ability of different irrigant delivery and/or agitation systems to reach the apical third of curved root canals; however, little is known about irrigant penetration in vivo. Therefore, the purpose of this study was to compare the efficacy of the conventional endodontic irrigation needle, passive ultrasonic irrigation (PUI), and a negative pressure system for irrigant delivery to working length (WL) of mesial canals of mandibular molars. Thirty mesial canals of 30 vital mandibular first or second molars were randomly assigned into 3 groups (n = 10): (1) Monoject syringe with 27-gauge needle; (2) PUI with IrriSafe tip; and (3) EndoVac system. All canals were treated following the same preparation protocol to size 35/0.04 by using 5.25% NaOCl as irrigant during preparation procedure. Before obturation, canals were irrigated with 1 mL of a radiopaque solution by using the assigned irrigation system, and a digital radiograph was taken by using a parallel technique. With the aid of image editing software the distance between WL and maximum irrigant penetration was measured. Mean distances for Monoject, PUI, and EndoVac groups were 1.51 mm, 0.21 mm, and 0.42 mm, respectively. Analysis of variance test showed statistically significant differences between groups (P < .001). Tukey honestly significant difference test showed statistically significant differences between the Monoject group and the other 2 groups (P < .001) but no significant differences between PUI and EndoVac groups (P = .06). PUI and EndoVac are more effective than the conventional endodontic needle in delivering irrigant to WL of root canals. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Antibacterial and residual antimicrobial activities against Enterococcus faecalis biofilm: A comparison between EDTA, chlorhexidine, cetrimide, MTAD and QMix.

PubMed

Zhang, Rui; Chen, Min; Lu, Yan; Guo, Xiangjun; Qiao, Feng; Wu, Ligeng

2015-08-06

We compared the antibacterial and residual antimicrobial activities of five root canal irrigants (17% EDTA,2% chlorhexidine,0.2% cetrimide, MTAD, and QMix) in a model of Enterococcus faecalis biofilm formation. Sixty dentin blocks with 3-week E. faecalis biofilm were divided into six equal groups and flushed with irrigant for 2 min or left untreated. A blank control group was also established. Antibacterial activities of the irrigants were evaluated by counting colony forming units. To test residual antimicrobial activities, 280 dentin blocks were divided into seven equal groups and flushed with irrigant for 2 min or left untreated and then incubated with E. faecalis suspension for 48 h, or used as a blank. No bacteria were observed in the blank control group. The number of viable E. faecalis was significantly fewer in the irrigant-treated groups compared with the untreated control (P < 0.05). Among the five irrigants, QMix had the strongest antibacterial activity. Residual antimicrobial activities of CHX were significantly higher at 12 h, 24 h and 36 h compared to untreated control (P < 0.05). All five root canal irrigants were effective to some extent against E. faecalis, but QMix and CHX had the strongest, and CHX the longest (up to 36 h), antimicrobial activity.

Effectiveness of supplementary irrigant agitation with the Finisher GF Brush on the debridement of oval root canals instrumented with the Gentlefile or nickel titanium rotary instruments.

PubMed

Neelakantan, P; Khan, K; Li, K Y; Shetty, H; Xi, W

2018-07-01

To examine the efficacy of a novel supplementary irrigant agitating brush (Finisher GF Brush, MedicNRG, Kibbutz Afikim, Israel) on the debridement of root canals prepared with a novel stainless steel rotary instrumentation system (Gentlefile; MedicNRG), or nickel titanium rotary instruments in oval root canals. Mandibular premolars (n = 72) were selected and divided randomly into three experimental groups (n = 24) after microCT scanning: group 1, canal preparation to rotary NiTi size 20, .04 taper (R20); group 2, rotary NiTi to size 25, .04 taper (R25) and group 3, Gentlefile size 23, .04 taper (GF). Specimens were subdivided into two subgroups: subgroup A, syringe-and-needle irrigation (SNI); subgroup B, Finisher GF Brush (GB). Ten untreated canals served as controls. Specimens were processed for histological evaluation, and the remaining pulp tissue (RPT) was measured. Data were analysed using Mann-Whitney and Kruskal-Wallis tests (P = 0.05). All experimental groups had significantly less RPT than the control (P < 0.05). Group 3B (GF-GB) had significantly less RPT than groups 1B (R20-GB) and 2B (R25-GF; P < 0.05). When irrigated with SNI, there was no significant difference in the RPT between the three groups (P > 0.05). When instrumented with R20, there was no significant difference between SNI and GF (P < 0.05) whilst GB had significantly less RPT than SNI for R25 (P < 0.05). Supplementary irrigant agitation with the Finisher GF Brush improved the debridement of canals prepared with Gentlefile and size 25, .04 taper rotary NiTi. Root canal debridement did not significantly differ between the instruments when syringe irrigation was used. © 2018 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Investigations into in situ Enterococcus faecalis biofilm removal by passive and active sodium hypochlorite irrigation delivered into the lateral canal of a simulated root canal model.

PubMed

Mohmmed, S A; Vianna, M E; Penny, M R; Hilton, S T; Mordan, N J; Knowles, J C

2018-06-01

To investigate in situ Enterococcus faecalis biofilm removal from the lateral canal of a simulated root canal system using passive or active irrigation protocols. Root canal models (n = 43) were manufactured from transparent resin materials using 3D printing. Each canal was created with an 18 mm length, apical size 30, a .06 taper and a lateral canal of 3 mm length, with 0.3 mm diameter. Biofilms were grown in the lateral canal and apical 3 mm of the main canal for 10 days. Three models from each group were examined for residual biofilm using SEM. The other forty models were divided into four groups (n = 10). The models were observed under a fluorescence microscope. Following 60 s of 9 mL of 2.5% NaOCl irrigation using syringe and needle, the irrigant was either left stagnant in the canal or activated using gutta-percha, sonic or ultrasonic methods for 30 s. Images were then captured every second using an external camera. The residual biofilm percentages were measured using image analysis software. The data were analysed using generalized linear mixed models. A significance level of 0.05 was used throughout. The greatest level of biofilm removal was obtained with ultrasonic agitation (66.76%) followed by sonic (45.49%), manual agitation (43.97%) and passive irrigation groups (38.67%), respectively. The differences were significant between the residual biofilm in the passive irrigation and both sonic and ultrasonic groups (P = 0.001). Agitation resulted in better penetration of 2.5% NaOCl into the lateral canal of an artificial root canal model. Ultrasonic agitation of NaOCl improved the removal of biofilm. © 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Effects of furrow irrigation on the growth, production, and water use efficiency of direct sowing rice.

PubMed

He, Chunlin

2010-08-03

Rice farming is the major crop production in Asia and is predicted to increase significantly in the near future in order to meet the demands for the increasing human population. Traditional irrigation methods used in rice farming often result in great water loss. New water-saving methods are urgently needed to reduce water consumption. Three field and pot experiments were conducted to evaluate the furrow irrigation (FI) system to improve water use efficiency (WUE) and production of direct sowing rice in southern China. Compared to the conventional irrigation (CI) system (continuous flooding irrigation), for every square hectometer of rice field, the FI system reduced water use by 3130 m3, or 48.1%, and increased grain production by 13.9% for an early cultivar. For a late cultivar, the FI system reduced water use by 2655 m3, or 40.6%, and an increase of grain production by 12.1%. The improved WUE in the FI system is attributed to (1) a significant reduction of irrigation rate, seepage, evaporation, and evapotranspiration; (2) a significant reduction in the reduced materials, such as ferrous ion (Fe2+), and therefore an increase in the vitality of the root system, evident by the increases in the number of white roots by 32.62%, and decreases in the number of black roots by 20.04% and yellow roots by 12.58%; the use of the FI system may also reduce humidity of the rice field and enhance gas transport in the soil and light penetration, which led to reduced rice diseases and increased leaf vitality; and (3) increases in tiller and effective spikes by 11.53% and the weight per thousand grains by 1.0 g. These findings suggest that the shallow FI system is a promising means for rice farming in areas with increasing water shortages.

Vertical Distribution of Pasteuria penetrans Parasitizing Meloidogyne incognita on Pittosporum tobira in Florida.

PubMed

Baidoo, Richard; Mengistu, Tesfamariam Mekete; Brito, Janete A; McSorley, Robert; Stamps, Robert H; Crow, William T

2017-09-01

Pasteuria penetrans is considered as the primary agent responsible for soil suppressiveness to root-knot nematodes widely distributed in many agricultural fields. A preliminary survey on a Pittosporum tobira field where the grower had experienced a continuous decline in productivity caused by Meloidogyne incognita showed that the nematode was infected with Pasteuria penetrans . For effective control of the nematode, the bacterium and the host must coexist in the same root zone. The vertical distribution of Pasteuria penetrans and its relationship with the nematode host in the soil was investigated to identify (i) the vertical distribution of P. penetrans endospores in an irrigated P. tobira field and (ii) the relationship among P. penetrans endospore density, M. incognita J2 population density, and host plant root distribution over time. Soil bioassays revealed that endospore density was greater in the upper 18 cm of the top soil compared with the underlying depths. A correlation analysis showed that the endospore density was positively related to the J2 population density and host plant root distribution. Thus, the vertical distribution of P. penetrans was largely dependent on its nematode host which in turn was determined by the distribution of the host plant roots. The Pasteuria was predominant mostly in the upper layers of the soil where their nematode host and the plant host roots are abundant, a factor which may be a critical consideration when using P. penetrans as a nematode biological control agent.

Vertical Distribution of Pasteuria penetrans Parasitizing Meloidogyne incognita on Pittosporum tobira in Florida

PubMed Central

Baidoo, Richard; Mengistu, Tesfamariam Mekete; Brito, Janete A.; McSorley, Robert; Stamps, Robert H.; Crow, William T.

2017-01-01

Pasteuria penetrans is considered as the primary agent responsible for soil suppressiveness to root-knot nematodes widely distributed in many agricultural fields. A preliminary survey on a Pittosporum tobira field where the grower had experienced a continuous decline in productivity caused by Meloidogyne incognita showed that the nematode was infected with Pasteuria penetrans. For effective control of the nematode, the bacterium and the host must coexist in the same root zone. The vertical distribution of Pasteuria penetrans and its relationship with the nematode host in the soil was investigated to identify (i) the vertical distribution of P. penetrans endospores in an irrigated P. tobira field and (ii) the relationship among P. penetrans endospore density, M. incognita J2 population density, and host plant root distribution over time. Soil bioassays revealed that endospore density was greater in the upper 18 cm of the top soil compared with the underlying depths. A correlation analysis showed that the endospore density was positively related to the J2 population density and host plant root distribution. Thus, the vertical distribution of P. penetrans was largely dependent on its nematode host which in turn was determined by the distribution of the host plant roots. The Pasteuria was predominant mostly in the upper layers of the soil where their nematode host and the plant host roots are abundant, a factor which may be a critical consideration when using P. penetrans as a nematode biological control agent. PMID:29062154

In vitro study of calcium hydroxide removal from mandibular molar root canals.

PubMed

Ma, Jingzhi; Shen, Ya; Yang, Yan; Gao, Yuan; Wan, Pan; Gan, Yan; Patel, Payal; Curtis, Allison; Khakpour, Mehrzad; Haapasalo, Markus

2015-04-01

Previous studies have shown the difficulty in removing calcium hydroxide (Ca[OH]2) paste from the root canals before root filling. Mesial and distal canals of 30 mandibular molars were prepared with the WaveOne Primary (25/.08) and Large file (40/.08) (Dentsply Tulsa Dental Specialties, Tulsa, OK), respectively. All canals were then filled with Ca(OH)2. The teeth were divided into the following 3 treatment groups (each with n = 10): (1) instrumentation with needle irrigation, (2) instrumentation with irrigation and passive ultrasonic activation (PUI), and (3) the GentleWave system (Sonendo, Inc, Laguna Hills, CA) without instrumentation. The irrigation time in each group was 7.5 minutes. To further test the efficiency of the GentleWave system, shorter times of 90 seconds were tested using water alone. Reconstructed micro-computed tomographic scans were used to measure the volume of the canals and Ca(OH)2 after instrumentation, initial filling of Ca(OH)2, and after its removal. The percentage of Ca(OH)2 remaining in the canals was calculated. None of the 10 teeth (30 canals) in the conventional irrigation and PUI groups were completely cleaned of Ca(OH)2 in 7.5 minutes. In the apical third of mesial and distal canals, respectively, conventional irrigation removed 47.82% ± 16.36% and 77.68% ± 12.82%, PUI removed 61.66% ± 25.54% and 88.85 ± 12.06%, and the GentleWave system removed significantly more Ca(OH)2 (P < .05) with 100% and 98.78% ± 3.84%. Additional experiments in 10 teeth, using only water as the irrigant, revealed that the GentleWave system removed 99.85% and 99.97% of Ca(OH)2 within 90 seconds without the use of any instruments in the mesial and distal canals, respectively. The study confirms the difficulty to remove Ca(OH)2 from root canals using conventional methods. The GentleWave system removed the paste within 90 seconds using water irrigation alone. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

The fluid mechanics of root canal irrigation.

PubMed

Gulabivala, K; Ng, Y-L; Gilbertson, M; Eames, I

2010-12-01

Root canal treatment is a common dental operation aimed at removing the contents of the geometrically complex canal chambers within teeth; its purpose is to remove diseased or infected tissue. The complex chamber is first enlarged and shaped by instruments to a size sufficient to deliver antibacterial fluids. These irrigants help to dissolve dying tissue, disinfect the canal walls and space and flush out debris. The effectiveness of the procedure is limited by access to the canal terminus. Endodontic research is focused on finding the instruments and clinical procedures that might improve success rates by more effectively reaching the apical anatomy. The individual factors affecting treatment outcome have not been unequivocally deciphered, partly because of the difficulty in isolating them and in making the link between simplified, general experimental models and the complex biological objects that are teeth. Explicitly considering the physical processes within the root canal can contribute to the resolution of these problems. The central problem is one of fluid motion in a confined geometry, which makes the dispersion and mixing of irrigant more difficult because of the absence of turbulence over much of the canal volume. The effects of treatments can be understood through the use of scale models, mathematical modelling and numerical computations. A particular concern in treatment is that caustic irrigant may penetrate beyond the root canal, causing chemical damage to the jawbone. In fact, a stagnation plane exists beyond the needle tip, which the irrigant cannot penetrate. The goal is therefore to shift the stagnation plane apically to be coincident with the canal terminus without extending beyond it. Needle design may solve some of the problems but the best design for irrigant penetration conflicts with that for optimal removal of the bacterial biofilm from the canal wall. Both irrigant penetration and biofilm removal may be improved through canal fluid agitation using a closely fitting instrument or by sonic or ultrasonic activation. This review highlights a way forward by understanding the physical processes involved through physical models, mathematical modelling and numerical computations.

Effect of woody and herbaceous plants on chemical weathering of basalt material

NASA Astrophysics Data System (ADS)

Mark, N.; Dontsova, K.; Barron-Gafford, G. A.

2011-12-01

Worldwide, semi-arid landscapes are transitioning from shallow-rooted grasslands to mixed vegetation savannas composed of deeper-rooted shrubs. These contrasting growth forms differentially drive below-ground processes because they occupy different soil horizons, are differentially stressed by periods of drought, and unequally stimulate soil weathering. Our study aims to determine the effect of woody and herbaceous plants on weathering of granular basalt serving as a model for soil. We established pots with velvet mesquite (Prosopis veluntina), sideoats grama (Bouteloua curtipendula), and bare-soil pots within two temperature treatments in University of Arizona Biosphere 2. The Desert biome served as the ambient temperature treatment, while the Savanna biome was maintained 4°C warmer to simulate projected air temperatures if climate change continues unabated. Rhizon water samplers were installed at a depth of one inch from the soil surface to monitor root zone exudates (total dissolved carbon and nitrogen), dissolved inorganic carbon, and lithogenic elements resulting from basalt weathering. Soil leachates were collected through the course of the experiment. The anion content of the leachates was determined using the ICS-5000 Reagent-Free ion chromatography system. Dissolved carbon and nitrogen were analyzed by combustion using the Shimadzu TOC-VCSH with TN module. Metals and metalloids were measured using inductively coupled plasma mass spectrometry. Irrigation of the pots was varied in time to simulate periods of drought and determine the effect of stress on root exudation. Leachates from all treatments displayed higher pH and electrical conductivity than water used for irrigation indicating weathering. On average, leachates from the potted grasses displayed higher pH and electrical conductivity than mesquites. This agreed with higher concentrations of organic carbon, a measure of root exudation, and inorganic carbon, measure of soil respiration. Both organic acids exuded by plants and respired CO2 have been linked to mineral weathering. Increased weathering in grass treatments also resulted in higher concentrations of plant nutrients. No effect of temperature on plant exudation or basalt weathering was observed in the course of the experiment. This work links physiological plant responses to temperature and water stress by two vegetation types with below-ground processes that result in soil evolution.

Colonic irrigation for defecation disorders after dynamic graciloplasty

PubMed Central

Koch, Sacha M.; Uludağ, Özenç; El Naggar, Kadri; van Gemert, Wim G.

2007-01-01

Background and aims Dynamic graciloplasty (DGP) improves anal continence and quality of life for most patients. However, in some patients, DGP fails and fecal incontinence is unsolved or only partially improved. Constipation is also a significant problem after DGP, occurring in 13–90%. Colonic irrigation can be considered as an additional or salvage treatment for defecation disorders after unsuccessful or partially successful DGP. In this study, the effectiveness of colonic irrigation for the treatment of persistent fecal incontinence and/or constipation after DGP is investigated. Materials and methods Patients with defecation disorders after DGP visiting the outpatient clinic of the University Hospital Maastricht were selected for colonic irrigation as additional therapy or salvage therapy in the period between January 1999 and June 2003. The Biotrol® Irrimatic pump or the irrigation bag was used for colonic irrigation. Relevant physical and medical history was collected. The patients were asked to fill out a detailed questionnaire about colonic irrigation. Results Forty-six patients were included in the study with a mean age of 59.3 ± 12.4 years (80% female). On average, the patients started the irrigation 21.39 ± 38.77 months after the DGP. Eight patients started irrigation before the DGP. Fifty-two percent of the patients used the irrigation as additional therapy for fecal incontinence, 24% for constipation, and 24% for both. Irrigation was usually performed in the morning. The mean frequency of irrigation was 0.90 ± 0.40 times per day. The mean amount of water used for the irrigation was 2.27 ± 1.75 l with a mean duration of 39 ± 23 min. Four patients performed antegrade irrigation through a colostomy or appendicostomy, with good results. Overall, 81% of the patients were satisfied with the irrigation. Thirty-seven percent of the patients with fecal incontinence reached (pseudo-)continence, and in 30% of the patients, the constipation completely resolved. Side effects of the irrigation were reported in 61% of the patients: leakage of water after irrigation, abdominal cramps, and distended abdomen. Seven (16%) patients stopped the rectal irrigation. Conclusion Colonic irrigation is an effective alternative for the treatment of persistent fecal incontinence after DGP and/or recurrent or onset constipation additional to unsuccessful or (partially) successful DGP. PMID:17896111

[Effects of arsenic from soil and irrigation-water on As accumulation on the root surfaces and in mature rice plants (Oryza sativa L.)].

PubMed

Liu, Wen-ju; Zhu, Yong-guan; Hu, Ying; Zhao, Quan-li

2008-04-01

A compartmented soil-glass bead culture system was used to investigate characteristics of arsenic accumulation in iron plaque and in mature rice plants irrigated using water with arsenic in greenhouse. Arsenic was supplied as a solution of Na3AsO4 * 12H2O at the following stages: tillering, stem elongation, booting, flowering and grain filling. The whole plant was separated into four parts and As concentrations were analyzed in DCB (dithionite-citrate-bicarbonate)-extraction, root, straw, rice husk and grain respectively. The results show that irrigation-water with arsenic has no significant effect on biomass of straw and grain. Arsenic concentrations are distributed in different components of mature rice with the ranking of iron plaque > root > straw > husk > grain. Arsenic in straw and grain just derive from soil in control, and derive from soil and irrigation-water in arsenic treatment. About 76.5% and 71.0% of total arsenic in rice straw are from soil for lines of YY-1 and 94D-64 respectively. There is no significant difference between two lines. However, about 33.6% of total arsenic in grain of YY-1 comes from irrigation-water with arsenic, and only 15.2% of total arsenic in grain of 94D1-64 is from irrigation-water with arsenic. There is a significant difference between YY-1 and 94D-64. Arsenic concentrations in rice grain are lower than the food safety limitation in China (0.7 mg x kg(-1)).

[The use of self-adapting system files (SAF) for controlling microbial biofilms of root canals in the treatment of apical periodontitis].

PubMed

Tsarev, V N; Mamedova, L A; Siukaeva, T N; Podporin, M S

The aim of this study was to conduct a clinical and laboratory study and evaluate the effectiveness of endodontic root canal treatment using a self-adapting files system (SAF) in the complex treatment of patients with chronic apical periodontitis. 3% sodium hypochlorite solution was used as irrigation agent in all groups which included 20 patients treated with conventional manual tools, 21 patients receiving treatment with ultrasonic activation of irrigant and 26 patients treated with SAF system. Root canal biofilm structure was studied by scanning electron microscopy (SEM) using a Quantum 3D microscope (USA). Clinical efficiency of the root canal treatment was assessed by complications frequency a year after treatment. SEM revealed the presence of high levels of microbial contamination of dentine tubules in the apical portion of the tooth. In standard method group the percentage of re-treatment and surgery was higher than in the studied groups. Use of SAF irrigation system was associated with a decrease in the number of identified pathogens. However, the study revealed high resistance of Enterococcus spp., Porphyromonas gingivalis, Candida albicans to all types of endodontic treatment, so the improvement of methods of root canal microbial biofilms removing need to be continued.

Effects of arbuscular mycorrhizae on tomato yield, nutrient uptake, water relations, and soil carbon dynamics under deficit irrigation in field conditions.

PubMed

Bowles, Timothy M; Barrios-Masias, Felipe H; Carlisle, Eli A; Cavagnaro, Timothy R; Jackson, Louise E

2016-10-01

Plant strategies to cope with future droughts may be enhanced by associations between roots and soil microorganisms, including arbuscular mycorrhizal (AM) fungi. But how AM fungi affect crop growth and yield, together with plant physiology and soil carbon (C) dynamics, under water stress in actual field conditions is not well understood. The well-characterized mycorrhizal tomato (Solanum lycopersicum L.) genotype 76R (referred to as MYC+) and the mutant nonmycorrhizal tomato genotype rmc were grown in an organic farm with a deficit irrigation regime and control regime that replaced evapotranspiration. AM increased marketable tomato yields by ~25% in both irrigation regimes but did not affect shoot biomass. In both irrigation regimes, MYC+ plants had higher plant nitrogen (N) and phosphorus (P) concentrations (e.g. 5 and 24% higher N and P concentrations in leaves at fruit set, respectively), 8% higher stomatal conductance (gs), 7% higher photosynthetic rates (Pn), and greater fruit set. Stem water potential and leaf relative water content were similar in both genotypes within each irrigation regime. Three-fold higher rates of root sap exudation in detopped MYC+ plants suggest greater capacity for water uptake through osmotic driven flow, especially in the deficit irrigation regime in which root sap exudation in rmc was nearly absent. Soil with MYC+ plants also had slightly higher soil extractable organic C and microbial biomass C at anthesis but no changes in soil CO2 emissions, although the latter were 23% lower under deficit irrigation. This study provides novel, field-based evidence for how indigenous AM fungi increase crop yield and crop water use efficiency during a season-long deficit irrigation and thus play an important role in coping with increasingly limited water availability in the future. Copyright © 2016 Elsevier B.V. All rights reserved.

Investigation of the Efficacy of Passive Ultrasonic Irrigation Versus Irrigation with Reciprocating Activation: An Environmental Scanning Electron Microscopic Study.

PubMed

Kato, Augusto Shoji; Cunha, Rodrigo Sanches; da Silveira Bueno, Carlos Eduardo; Pelegrine, Rina Andrea; Fontana, Carlos Eduardo; de Martin, Alexandre Sigrist

2016-04-01

The objective of this ex vivo study was to compare the efficacy of passive ultrasonic irrigation (PUI) versus a new activation system using reciprocating motion (EasyClean [EC]; Easy Equipamentos Odontológicos, Belo Horizonte, Brazil) to remove debris from the root canal walls at 6 predetermined apical levels using environmental scanning electron microscopy. Mesiobuccal root canals of 10 mandibular molars were prepared with a 30/.05 final instrument. The specimens were embedded in flasks containing heavy body silicone, cleaved longitudinally, and 6 round indentations were made into the apical region of the buccal half at 1-mm intervals. The same specimens were used to prepare a blank control group (no debris), a negative control group (completely covered by debris), and 2 experimental groups: PUI and irrigation with reciprocating activation. Standardized images of the indentations were obtained under environmental scanning electron microscopy and assessed by 2 examiners. The amount of debris was then classified using a 4-category scoring system. The kappa test was applied to determine interexaminer agreement, whereas the Kruskal-Wallis, Dunn, and Friedman tests were used to compare scores. The EC group had results statistically similar to those of the blank control group for all 6 root levels examined. The PUI group had results statistically similar to those of the negative control group for the 3 most apical levels and similar to those of the blank control group for the 3 most cervical levels. Activating the irrigant with a reciprocating system (EC) promoted more effective debris removal from the more apical regions of the root canal when compared with PUI. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Clonal variation in lateral and basal rooting of Populus irrigated with landfill leachate

Treesearch

R.S. Zalesny Jr.; J.A. Zalesny

2011-01-01

Successful establishment and productivity of Populus depends upon adventitious rooting from: 1) lateral roots that develop from either preformed or induced primordia and 2) basal roots that differentiate from callus at the base of the cutting in response to wounding. Information is needed for phytotechnologies about the degree to which ...

Monitoring Contamination of the subsurface with Quasi-Static Deformation

NASA Astrophysics Data System (ADS)

Spetzler, H.; Snieder, R.; Zhang, J.

2005-12-01

Data from a field experiment suggest that we can detect the infiltration of contaminated water (contaminated with 150 ppm of a biosurfactant, Rhamnolipid) into the vadose zone with tilt meters. Three sets of instruments were installed in the vicinity of a 50m x 50m field, which was instrumented and could be irrigated in a controlled manner. Each set consisted of one tiltmeter at the bottom of a 10m cased borehole and one seismometer buried to a depth of about 1m. The instruments were installed in late summer and early fall of 2002. The drift in tilt caused by their installation decayed to near background levels in about one year. The site was irrigated with plain water at 50,000 l/day for 40 days during the fall of 2003. The irrigation was repeated in the fall of 2004 for 50 days, again with 50,000 l/day. This time the irrigation water contained 150ppm of a biosurfactant. This surfactant was chosen to simulate a contaminant through its effect on the modification of surface tension and because it is environmentally benign. It was developed for bioremediation. We expected subtle changes in the relative responses of the instruments as the elastic properties of the vadose zone were altered by the contaminant. This expectation is based on a long series of laboratory measurements, e.g. W. Brunner and H.A. Spetzler 2002. We used natural sources for the excitation of the instruments, solid Earth tides for the tiltmeters and microseisms, i.e. ocean generated noise at about 6s periods, for the seismometers. In the case of the tilt meters we used theoretical site specific tilt and compared that with our measured tilt. We found no significant change in the correlation coefficient between theoretical and measured tilt for the water-only irrigation. The correlation coefficient was generally above 0.9. The correlation coefficient dropped precipitously about ten days after we had started irrigating with the surfactant. It recovered again about ten days after irrigation was stopped. A preliminary analysis of the seismic data shows similar trends, but with much more noise. Using a Born approximation we calculate that a slight perturbation of the complex moduli near the surface does indeed yield changes in tidally-induced tilt near the observed values. Brunner, W. M. and H. A. Spetzler, Contaminant-Induced Mechanical Damping in Partially Saturated Berea Sandstone, Geophys. Res. Lett., Vol.29, No.16, 10.1029/2002GL015455 ,2002

A case study of field-scale maize irrigation patterns in western Nebraska: implications for water managers and recommendations for hyper-resolution land surface modeling

NASA Astrophysics Data System (ADS)

Gibson, Justin; Franz, Trenton E.; Wang, Tiejun; Gates, John; Grassini, Patricio; Yang, Haishun; Eisenhauer, Dean

2017-02-01

In many agricultural regions, the human use of water for irrigation is often ignored or poorly represented in land surface models (LSMs) and operational forecasts. Because irrigation increases soil moisture, feedback on the surface energy balance, rainfall recycling, and atmospheric dynamics is not represented and may lead to reduced model skill. In this work, we describe four plausible and relatively simple irrigation routines that can be coupled to the next generation of hyper-resolution LSMs operating at scales of 1 km or less. The irrigation output from the four routines (crop model, precipitation delayed, evapotranspiration replacement, and vadose zone model) is compared against a historical field-scale irrigation database (2008-2014) from a 35 km2 study area under maize production and center pivot irrigation in western Nebraska (USA). We find that the most yield-conservative irrigation routine (crop model) produces seasonal totals of irrigation that compare well against the observed irrigation amounts across a range of wet and dry years but with a low bias of 80 mm yr-1. The most aggressive irrigation saving routine (vadose zone model) indicates a potential irrigation savings of 120 mm yr-1 and yield losses of less than 3 % against the crop model benchmark and historical averages. The results of the various irrigation routines and associated yield penalties will be valuable for future consideration by local water managers to be informed about the potential value of irrigation saving technologies and irrigation practices. Moreover, the routines offer the hyper-resolution LSM community a range of irrigation routines to better constrain irrigation decision-making at critical temporal (daily) and spatial scales (< 1 km).

Hydraulic characteristics of an underdrained irrigation circle, Muskegon County, wastewater disposal system, Michigan

USGS Publications Warehouse

McDonald, M.G.

1981-01-01

Muskegon County, Michigan, disposes of waste water by spray irrigating farmland on its waste-disposal site. Buried drains in the highly permeable unconfined aquifer at the site control the level of the water table. Hydraulic conductivity of the aquifer and drain-leakance, the reciprocal of resistance to flow into the drains, was determined at a representative irrigation circle while calibrating a model of the ground-water flow system. Hydraulic conductivity is 0.00055 meter per second in the north zone of the circle and 0.00039 meter per second in the south zone. Drain leakance is low in both zones: 2.9 x 10-6 meters per second in the north and 9.5 x 10-6 meters per second in the south. Low drain leakance is responsible for waterlogging when irrigation rates are maintained at design levels. The capacity of the study circle to accept waste water is 35 percent less than design capacity.

Geospatial distribution modeling and determining suitability of groundwater quality for irrigation purpose using geospatial methods and water quality index (WQI) in Northern Ethiopia

NASA Astrophysics Data System (ADS)

Gidey, Amanuel

2018-06-01

Determining suitability and vulnerability of groundwater quality for irrigation use is a key alarm and first aid for careful management of groundwater resources to diminish the impacts on irrigation. This study was conducted to determine the overall suitability of groundwater quality for irrigation use and to generate their spatial distribution maps in Elala catchment, Northern Ethiopia. Thirty-nine groundwater samples were collected to analyze and map the water quality variables. Atomic absorption spectrophotometer, ultraviolet spectrophotometer, titration and calculation methods were used for laboratory groundwater quality analysis. Arc GIS, geospatial analysis tools, semivariogram model types and interpolation methods were used to generate geospatial distribution maps. Twelve and eight water quality variables were used to produce weighted overlay and irrigation water quality index models, respectively. Root-mean-square error, mean square error, absolute square error, mean error, root-mean-square standardized error, measured values versus predicted values were used for cross-validation. The overall weighted overlay model result showed that 146 km2 areas are highly suitable, 135 km2 moderately suitable and 60 km2 area unsuitable for irrigation use. The result of irrigation water quality index confirms 10.26% with no restriction, 23.08% with low restriction, 20.51% with moderate restriction, 15.38% with high restriction and 30.76% with the severe restriction for irrigation use. GIS and irrigation water quality index are better methods for irrigation water resources management to achieve a full yield irrigation production to improve food security and to sustain it for a long period, to avoid the possibility of increasing environmental problems for the future generation.

Effect of Aquatine Endodontic Cleanser on smear layer removal in the root canals of ex vivo human teeth.

PubMed

Garcia, Faustino; Murray, Peter E; Garcia-Godoy, Franklin; Namerow, Kenneth N

2010-01-01

The purpose of this study was to measure and compare the root canal cleanliness and smear layer removal effectiveness of Aquatine Endodontic Cleanser (Aquatine EC) when used as an endodontic irrigating solution in comparison with 6% sodium hypochlorite (NaOCl). Forty-five human teeth were randomly allocated to five treatment groups; the pulp chamber was accessed, cleaned, and shaped by using ProTaper and ProFile rotary instrumentation to an ISO size #40. The teeth were then processed for scanning electron microscopy, and the root canal cleanliness and removal of smear layer were examined. The most effective removal of smear layer occurred with Aquatine EC and NaOCl, both with a rinse of EDTA. Aquatine EC appears to be the first hypochlorous acid approved by the FDA to be a possible alternative to the use of NaOCl as an intracanal irrigant. Further research is needed to identify safer and more effective alternatives to the use of NaOCl irrigation in endodontics.

Evaluation of the influence of time and concentration of sodium hypochlorite on the bond strength of glass fibre post.

PubMed

Knight, Beau; Love, Robert M; George, Roy

2017-10-24

This study evaluated the effect of time and concentrations of sodium hypochlorite on the bond strength of a glass fibre post cemented in a root canal with resin cement. A total of 45 single-rooted extracted human teeth were prepared with Protaper ® universal files, randomly allocated into nine groups and then subjected to 1% or 4% NaOCl for a period of 1 min or 2 min. Fibre posts were then bonded into the root canal, sectioned and the bond strength tested using a push-out test. A longer irrigation time resulted in a significant reduction (P < 0.05) in bond strength, while a final additional irrigation with distilled water significantly reduced bond strength. The concentration of NaOCl did not significantly affect bond strength. Within the limitations of this study, it was observed that regardless of the concentration of NaOCl used, shorter irrigation times favoured better fibre post bonding. © 2017 Australian Society of Endodontology Inc.

Antibacterial effect of chlorhexidine-cetrimide combination, Salvia officinalis plant extract and octenidine in comparison with conventional endodontic irrigants.

PubMed

Guneser, Mehmet Burak; Akbulut, Makbule Bilge; Eldeniz, Ayce Unverdi

2016-01-01

The aim of the present study was to compare the antimicrobial effect of sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), a CHX/cetrimide solution (CHX+CTR), octenidine hydrochloride (OCT) and Salvia officinalis plant extract against Enterococcus faecalis. Seventy decoronated single-rooted human teeth were infected and divided into 6 test (n=10) and 2 control groups (n=5) (negative, sterile samples and positive, infected samples). Following irrigants were then applied to test groups: 2.5% NaOCl, 5.25% NaOCl, CHX, CHX+CTR, S. officinalis extract and OCT. The dentin chips were obtained from inner root canal walls and analyzed by counting the number of colony forming units (CFU). The 2.5% NaOCl, 5.25% NaOCl, CHX and OCT groups presented no bacterial growth (CFU=0). S. officinalis and CHX+CTR groups reduced the number of E. faecalis cells but could not eliminate all. OCT may have potential as an endodontic irrigant in treatment of infected root canals.

Closing the loop: integrating human impacts on water resources to advanced land surface models

NASA Astrophysics Data System (ADS)

Zaitchik, B. F.; Nie, W.; Rodell, M.; Kumar, S.; Li, B.

2016-12-01

Advanced Land Surface Models (LSMs), including those used in the North American Land Data Assimilation System (NLDAS), offer a physically consistent and spatially and temporally complete analysis of the distributed water balance. These models are constrained both by physically-based process representation and by observations ingested as meteorological forcing or as data assimilation updates. As such, they have become important tools for hydrological monitoring and long-term climate analysis. The representation of water management, however, is extremely limited in these models. Recent advances have brought prognostic irrigation routines into models used in NLDAS, while assimilation of Gravity Recovery and Climate Experiment (GRACE) derived estimates of terrestrial water storage anomaly has made it possible to nudge models towards observed states in water storage below the root zone. But with few exceptions these LSMs do not account for the source of irrigation water, leading to a disconnect between the simulated water balance and the observed human impact on water resources. This inconsistency is unacceptable for long-term studies of climate change and human impact on water resources in North America. Here we define the modeling challenge, review instances of models that have begun to account for water withdrawals (e.g., CLM), and present ongoing efforts to improve representation of human impacts on water storage across models through integration of irrigation routines, water withdrawal information, and GRACE Data Assimilation in NLDAS LSMs.

Antibacterial Effect of Azadirachta indica (Neem) or Curcuma longa (Turmeric) against Enterococcus faecalis Compared with That of 5% Sodium Hypochlorite or 2% Chlorhexidine in vitro.

PubMed

Joy Sinha, Dakshita; D S Nandha, Kanwar; Jaiswal, Natasha; Vasudeva, Agrima; Prabha Tyagi, Shashi; Pratap Singh, Udai

2017-01-01

The purpose of this study was to compare the antibacterial properties of Azadirachta indica (neem) or Curcuma longa (turmeric) against Enterococcus faecalis with those of 5% sodium hypochlorite or 2% chlorhexidine as root canal irrigants in vitro. The activity of neem, chlorhexidine, sodium hypochlorite, or turmeric against E. faecalis was measured on agar plates using the agar diffusion method. The tube dilution method was used to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the irrigants used. Chlorhexidine or neem exhibited the greatest antibacterial activity when used as endodontic irrigants against E. faecalis, followed by sodium hypochlorite. No statistically significant difference was observed between neem, sodium hypochlorite, or chlorhexidine. The MIC of neem was 1: 128, which was similar to that of chlorhexidine. The MBC for each of these irrigants was 1: 16. Neem yielded antibacterial activity equivalent to 2% chlorhexidine or sodium hypochlorite against E. faecalis, suggesting that it offers a promising alternative to the other root canal irrigants tested.

Antibacterial efficacy of Mangifera indica L. kernel and Ocimum sanctum L. leaves against Enterococcus faecalis dentinal biofilm

PubMed Central

Subbiya, Arunajatesan; Mahalakshmi, Krishnan; Pushpangadan, Sivan; Padmavathy, Kesavaram; Vivekanandan, Paramasivam; Sukumaran, Vridhachalam Ganapathy

2013-01-01

Introduction: The Enterococcus faecalis biofilm in the root canal makes it difficult to be eradicated by the conventional irrigants with no toxicity to the tissues. Hence, plant products with least side effects are explored for their use as irrigants in the root canal therapy. Aim: To evaluate and compare the antibacterial efficacy of Mangifera indica L. kernel (mango kernel) and Ocimum sanctum L. leaves (tulsi) extracts with conventional irrigants (5% sodium hypochlorite (NaOCl) and 2% chlorhexidine) against E. faecalis dentinal biofilm. Materials and Methods: Agar diffusion and broth microdilution assay was performed with the herbal extracts and conventional irrigants (2% chlorhexidine and 5% NaOCl) against E. faecalis planktonic cells. The assay was extended onto 3 week E. faecalis dentinal biofilm. Results: Significant reduction of colony forming units (CFU)/mL was observed for the herbal groups and the antibacterial activity of the herbal groups was at par with 5% NaOCl. Conclusions: The antibacterial activity of these herbal extracts is found to be comparable with that of conventional irrigants both on the biofilm and planktonic counterparts. PMID:24082577

Computer-based video digitizer analysis of surface extension in maize roots: kinetics of growth rate changes during gravitropism

NASA Technical Reports Server (NTRS)

Ishikawa, H.; Hasenstein, K. H.; Evans, M. L.

1991-01-01

We used a video digitizer system to measure surface extension and curvature in gravistimulated primary roots of maize (Zea mays L.). Downward curvature began about 25 +/- 7 min after gravistimulation and resulted from a combination of enhanced growth along the upper surface and reduced growth along the lower surface relative to growth in vertically oriented controls. The roots curved at a rate of 1.4 +/- 0.5 degrees min-1 but the pattern of curvature varied somewhat. In about 35% of the samples the roots curved steadily downward and the rate of curvature slowed as the root neared 90 degrees. A final angle of about 90 degrees was reached 110 +/- 35 min after the start of gravistimulation. In about 65% of the samples there was a period of backward curvature (partial reversal of curvature) during the response. In some cases (about 15% of those showing a period of reverse bending) this period of backward curvature occurred before the root reached 90 degrees. Following transient backward curvature, downward curvature resumed and the root approached a final angle of about 90 degrees. In about 65% of the roots showing a period of reverse curvature, the roots curved steadily past the vertical, reaching maximum curvature about 205 +/- 65 min after gravistimulation. The direction of curvature then reversed back toward the vertical. After one or two oscillations about the vertical the roots obtained a vertical orientation and the distribution of growth within the root tip became the same as that prior to gravistimulation. The period of transient backward curvature coincided with and was evidently caused by enhancement of growth along the concave and inhibition of growth along the convex side of the curve, a pattern opposite to that prevailing in the earlier stages of downward curvature. There were periods during the gravitropic response when the normally unimodal growth-rate distribution within the elongation zone became bimodal with two peaks of rapid elongation separated by a region of reduced elongation rate. This occurred at different times on the convex and concave sides of the graviresponding root. During the period of steady downward curvature the elongation zone along the convex side extended farther toward the tip than in the vertical control. During the period of reduced rate of curvature, the zone of elongation extended farther toward the tip along the concave side of the root. The data show that the gravitropic response pattern varies with time and involves changes in localized elongation rates as well as changes in the length and position of the elongation zone. Models of root gravitropic curvature based on simple unimodal inhibition of growth along the lower side cannot account for these complex growth patterns.

Identifying Developmental Zones in Maize Lateral Root Cell Length Profiles using Multiple Change-Point Models

PubMed Central

Moreno-Ortega, Beatriz; Fort, Guillaume; Muller, Bertrand; Guédon, Yann

2017-01-01

The identification of the limits between the cell division, elongation and mature zones in the root apex is still a matter of controversy when methods based on cellular features, molecular markers or kinematics are compared while methods based on cell length profiles have been comparatively underexplored. Segmentation models were developed to identify developmental zones within a root apex on the basis of epidermal cell length profiles. Heteroscedastic piecewise linear models were estimated for maize lateral roots of various lengths of both wild type and two mutants affected in auxin signaling (rtcs and rum-1). The outputs of these individual root analyses combined with morphological features (first root hair position and root diameter) were then globally analyzed using principal component analysis. Three zones corresponding to the division zone, the elongation zone and the mature zone were identified in most lateral roots while division zone and sometimes elongation zone were missing in arrested roots. Our results are consistent with an auxin-dependent coordination between cell flux, cell elongation and cell differentiation. The proposed segmentation models could extend our knowledge of developmental regulations in longitudinally organized plant organs such as roots, monocot leaves or internodes. PMID:29123533

Sodium hypochlorite chemical burn in an endodontist's eye during canal treatment using operating microscope.

PubMed

Regalado Farreras, Desirée C; Puente, Carlos García; Estrela, Carlos

2014-08-01

This study describes a case of eye burn induced by sodium hypochlorite used as an irrigant during root canal preparation. A 24-year-old female endodontist was using an operating microscope during root canal treatment, and as the root canal was irrigated, the pressure cannula burst and the irrigant (3.5% sodium hypochlorite) came into direct contact with her left eye. She immediately sought ophthalmologic emergency care for pain, redness of the cornea, burning sensation, photophobia, intraocular pressure, and blurred vision. The initial treatment consisted of washing the eye with saline solution and administering analgesic and anti-inflammatory (steroid) medications. One day after the accident, a topical demulcent and hydroxypropyl medication were applied to the eyeball (conjunctiva), the eye was bandaged for 24 hours, and rest was prescribed for 7 days. Eight days later, a corneal ulcer was diagnosed, and antibiotic and anti-inflammatory (steroid) medications were used. Vision was restored without any sequelae 4 weeks after the accident. The endodontist was instructed to apply control medication (Lagricel; Sophia SA, Caracas, Venezuela) for 3 months and to return for ophthalmologic follow-up every 6 months. Sodium hypochlorite is an effective antibacterial irrigant indicated for the treatment of root canal infections. The tissue cytotoxicity highlights the need to inform the patient of the risk factors of accidents and enhance care with individual protection equipment for the patient and the professional during clinical procedures. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

A microleakage study of gutta-percha/AH Plus and Resilon/Real self-etch systems after different irrigation protocols.

PubMed

Prado, Maíra; Simão, Renata Antoun; Gomes, Brenda Paula Figueiredo de Almeida

2014-06-01

The development and maintenance of the sealing of the root canal system is the key to the success of root canal treatment. The resin-based adhesive material has the potential to reduce the microleakage of the root canal because of its adhesive properties and penetration into dentinal walls. Moreover, the irrigation protocols may have an influence on the adhesiveness of resin-based sealers to root dentin. The objective of the present study was to evaluate the effect of different irrigant protocols on coronal bacterial microleakage of gutta-percha/AH Plus and Resilon/Real Seal Self-etch systems. One hundred ninety pre-molars were used. The teeth were divided into 18 experimental groups according to the irrigation protocols and filling materials used. The protocols used were: distilled water; sodium hypochlorite (NaOCl)+eDTA; NaOCl+H3PO4; NaOCl+eDTA+chlorhexidine (CHX); NaOCl+H3PO4+CHX; CHX+eDTA; CHX+ H3PO4; CHX+eDTA+CHX and CHX+H3PO4+CHX. Gutta-percha/AH Plus or Resilon/Real Seal Se were used as root-filling materials. The coronal microleakage was evaluated for 90 days against Enterococcus faecalis. Data were statistically analyzed using Kaplan-Meier survival test, Kruskal-Wallis and Mann-Whitney tests. No significant difference was verified in the groups using chlorhexidine or sodium hypochlorite during the chemo-mechanical preparation followed by eDTA or phosphoric acid for smear layer removal. The same results were found for filling materials. However, the statistical analyses revealed that a final flush with 2% chlorhexidine reduced significantly the coronal microleakage. A final flush with 2% chlorhexidine after smear layer removal reduces coronal microleakage of teeth filled with gutta-percha/AH Plus or Resilon/Real Seal SE.

Expression of ABA synthesis and metabolism genes under different irrigation strategies and atmospheric VPDs is associated with stomatal conductance in grapevine (Vitis vinifera L. cv Cabernet Sauvignon)

PubMed Central

Speirs, Jim; Binney, Allan; Collins, Marisa; Edwards, Everard; Loveys, Brian

2013-01-01

The influence of different levels of irrigation and of variation in atmospheric vapour pressure deficit (VPD) on the synthesis, metabolism, and transport of abscisic acid (ABA) and the effects on stomatal conductance were examined in field-grown Cabernet Sauvignon grapevines. Xylem sap, leaf tissue, and root tissue were collected at regular intervals during two seasons in conjunction with measurements of leaf water potential (Ψleaf) and stomatal conductance (gs). The different irrigation levels significantly altered the Ψleaf and gs of the vines across both seasons. ABA abundance in the xylem sap was correlated with gs. The expression of genes associated with ABA synthesis, NCED1 and NCED2, was higher in the roots than in the leaves throughout and highest in the roots in mid January, a time when soil moisture declined and VPD was at its highest. Their expression in roots was also inversely related to the levels of irrigation and correlated with ABA abundance in the roots, xylem sap, and leaves. Three genes encoding ABA 8’-hydroxylases were isolated and their identities confirmed by expression in yeast cells. The expression of one of these, Hyd1, was elevated in leaves when VPD was below 2.0–2.5 kPa and minimal at higher VPD levels. The results provide evidence that ABA plays an important role in linking stomatal response to soil moisture status and that changes in ABA catabolism at or near its site of action allows optimization of gas exchange to current environmental conditions. PMID:23630325

Antimicrobial efficacy of 2.5% sodium hypochlorite, 2% chlorhexidine, and ozonated water as irrigants in mesiobuccal root canals with severe curvature of mandibular molars

PubMed Central

Pinheiro, Sergio Luiz; da Silva, Caio Cesar; da Silva, Lucas Augusto; Cicotti, Marina P.; Bueno, Carlos Eduardo da Silveira; Fontana, Carlos Eduardo; Pagrion, Letícia R.; Dalmora, Natália P.; Daque, Thaís T.; de Campos, Francisco UF

2018-01-01

Objective: The aim of this study is to evaluate the antimicrobial efficacy of 2.5% sodium hypochlorite, 2% chlorhexidine, and ozonated water on biofilms of Enterococcus faecalis, Streptococcus mutans, and Candida albicans in mesiobuccal root canals with severe curvature of mandibular molars. Materials and Methods: This was an experimental ex vivo study in microbiologic laboratory. Sixty mesiobuccal root canals with severe curvature of mandibular molars were contaminated with standard strains of E. faecalis, S. mutans, and C. albicans. The specimens were randomly divided into four groups (n = 15) according to irrigating solution: SH: 2.5% sodium hypochlorite; CH: 2% chlorhexidine; O3: ozonated water; and control: double-distilled water. The mesiobuccal root canals of all groups were instrumented with the WaveOne Gold Primary reciprocating system. Three cycles of instrumentation with three short in-and-out brushing motions were performed: (1) in the coronal third, (2) in the middle third, and (3) in the apical third of the canal. A ProGlider file was used before the first cycle. Statistical Analysis: Statistical analysis was performed using one-way analysis of variance followed by Tukey's multiple comparison test. Samples were collected for viable bacterial counts before and after instrumentation. Results: All groups showed significant biofilm reduction after irrigation (P < 0.01). After instrumentation, sodium hypochlorite (98.07%), chlorhexidine (98.31%), and ozonated water (98.02%) produced a significantly reduction in bacterial counts compared with double-distilled water (control, 72.98%) (P < 0.01). Conclusion: All irrigants tested in this study showed similar antimicrobial activity. Thus, ozonated water may be an option for microbial reduction in the root canal system. PMID:29657531

Evaluation of the smear layer removal and erosive capacity of EDTA, boric acid, citric acid and desy clean solutions: an in vitro study.

PubMed

Turk, Tugba; Kaval, Mehmet Emin; Şen, Bilge Hakan

2015-09-03

The purpose of this study was to investigate the smear layer removal and erosive capacity of various irrigation solutions with sequential use of NaOCl on instrumented root canal walls. The root canals of single-rooted teeth were instrumented with ProTaper rotary instrument. Then, the teeth were randomly divided into five experimental groups. The root canals were irrigated with one of the following solutions (5 mL/1 min): 5% EDTA, 5% boric acid (BA), a mixture of BA and CA, 2.5% citric acid (CA) and 5% Desy Clean. After irrigating with 2.5% NaOCl and distilled water, the roots were split into two halves and each half was prepared for SEM examination. Representative photographs were taken from each third at x500 and x1000 magnifications. Double blind scoring was performed by two calibrated observers for smear layer and erosion. The scores were statistically analyzed using Kruskal-Wallis, Dunn's post hoc and Spearman's correlation tests (p = 0.05). There were statistically significant differences among the solutions by means of smear layer and erosion (p < 0.05). While 2.5% CA solution was the most effective solution in removal of smear layer, it was also the most erosive solution (p < 0.05). 5% Desy Clean removed smear layer effectively and caused less erosion. There was a negative, but statistically significant correlation between presence of smear layer and erosion (r = -0.684; p < 0.0001). Desy Clean can be a promising agent as an irrigation solution with optimal smear layer removal capacity and less erosive effects.

Root responses to elevated CO2, warming, and irrigation in a semiarid grassland: integrating biomass, length, and lifespan in a 5-year field experiment

USDA-ARS?s Scientific Manuscript database

Plant roots mediate the impacts of environmental change on ecosystems, yet knowledge of root responses to environmental change is limited because few experiments manipulate multiple environmental factors and root dynamics are rarely measured thoroughly. Using five years of observations from an exper...

Root morphology and growth of bare-root seedlings of Oregon white oak

Treesearch

Peter J. Gould; Constance A. Harrington

2009-01-01

Root morphology and stem size were evaluated as predictors of height and basal-area growth (measured at groundline) of 1-1 Oregon white oak (Quercus garryana Dougl. ex Hook.) seedlings planted in raised beds with or without an additional irrigation treatment. Seedlings were classified into three root classes based on a visual assessment of the...

Micro-computed tomography evaluation of the removal of calcium hydroxide medicament from C-shaped root canals of mandibular second molars.

PubMed

Ma, J Z; Shen, Y; Al-Ashaw, A J; Khaleel, H Y; Yang, Y; Wang, Z J; Peng, B; Haapasalo, M

2015-04-01

To use micro-computed tomography (μ-CT) to evaluate the amount of calcium hydroxide [Ca(OH)2 ] remaining in the C-shaped root canals of mandibular second molars after attempting to remove it with passive ultrasonic and sonic irrigation. Thirty mandibular second molars, 15 in C1 and 15 in C2 configurations as first identified by μ-CT, were divided into three groups (five C1 and five C2 in each group) for the three irrigation methods. All teeth were prepared to ProTaper Universal F2 and filled with Ca(OH)2 paste. The Ca(OH)2 was removed with F2 files and irrigation without agitation or with agitation using either EndoActivator or ultrasonics. μ-CT was used to measure the initial amount of Ca(OH)2 present. After removal of Ca(OH)2, μ-CT imaging was used to assess the percentage of volume of residual Ca(OH)2 in the canal. Data were analysed using one-way anova test. There was no significant difference in the mean volume of the root canal systems after instrumentation amongst the three groups. The three irrigation techniques left 2-17% of Ca(OH)2 in the root canals after removal. The mean volume of the remaining Ca(OH)2 was higher in the group without agitation than in the groups with sonic or ultrasonic agitation (P < 0.05). In the apical third, 68% of the canal space remained occupied by Ca(OH)2 when no agitation was used, whereas 28% and 31% remained filled by Ca(OH)2 in the EndoActivator and ultrasonic groups, respectively. There was no significant difference in the amount of residual Ca(OH)2 between the EndoActivator and ultrasonic groups. The proportion of remaining Ca(OH)2 in the apical canals was higher than in the middle and coronal canals in all groups (P < 0.05). A considerable proportion of the apical canal space remained filled with Ca(OH)2 in the C-shaped root canals after instrumentation and conventional needle irrigation. Although combining rotary instrumentation and irrigation with sonic or ultrasonic agitation reduced the amount of residual Ca(OH)2 in the C-shaped root canals, the large amount of calcium hydroxide in the critical apical area remains a concern. Alternative strategies should be considered in medication of the apical canal in C-shaped teeth. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Yield response to variable rate irrigation in corn

USDA-ARS?s Scientific Manuscript database

To investigate the impact of variable rate irrigation on corn yield, twenty plots of corn were laid out under a center pivot variable rate irrigation (VRI) system in an experimental field near Stoneville, MS. The VRI system is equipped with five VRI zone control units, a global positioning system (G...

SDI increases water use efficiency of grain crops in the Southern High Plains

USDA-ARS?s Scientific Manuscript database

In the semi-arid Southern High Plains, nearly all irrigation water is derived from the declining High Plains (Ogallala) aquifer. As well capacities likewise decline, one tactic for continued irrigation is to install subsurface drip irrigation (SDI) systems with zones sized to accommodate the limited...

Adapting FAO-56 Spreadsheet Program to estimate olive orchard transpiration fluxes under soil water stress condition

NASA Astrophysics Data System (ADS)

Rallo, G.; Provenzano, G.; Manzano-Juárez, J.

2012-04-01

In the Mediterranean environment, where the period of crops growth does not coincide with the rainy season, the crop is subject to water stress periods that may be amplified with improper irrigation management. Agro-hydrological models can be considered an economic and simple tool to optimize irrigation water use, mainly when water represents a limiting factor for crop production. In the last two decades, agro-hydrological physically based models have been developed to simulate mass and energy exchange processes in the soil-plant-atmosphere system (Feddes et al., 1978; Bastiaanssen et al., 2007). Unfortunately these models, although very reliable, as a consequence of the high number of required variables and the complex computational analysis, cannot often be used. Therefore, simplified agro-hydrological models may represent an useful and simple tool for practical irrigation scheduling. The main objective of the work is to assess, for an olive orchard, the suitability of FAO-56 spreadsheet agro-hydrological model to estimate a long time series of field transpiration, soil water content and crop water stress dynamic. A modification of the spreadsheet is suggested in order to adapt the simulations to a crop tolerant to water stress. In particular, by implementing a new crop water stress function, actual transpiration fluxes and an ecophysiological stress indicator, i. e. the relative transpiration, are computed in order to evaluate a plant-based irrigation scheduling parameter. Validation of the proposed amendment is carried out by means of measured sap fluxes, measured on different plants and up-scaled to plot level. Spatial and temporal variability of soil water contents in the plot was measured, at several depths, using the Diviner 2000 capacitance probe (Sentek Environmental Technologies, 2000) and TDR-100 (Campbell scientific, Inc.) system. The detailed measurements of soil water content, allowed to explore the high spatial variability of soil water content due to the combined effect of the punctual irrigation and the non-uniform root density distribution. A further validation of the plant-based irrigation-timing indicator will be carried out by considering another ecophysiological stress variable like the predawn leaf water potential. Accuracy of the model output was assessed using the Mean Absolute Difference, the Root Mean Square Difference and the efficiency index of Nash and Sutcliffe. Experimental data, recorded during three years of field observation, allowed, with a great level of detail, to investigate on the dynamic of water fluxes from the soil to atmosphere as well as to validate the proposed amendment of the FAO-56 spreadsheet. The modified model simulated with a satisfactory approximation the measured values of average soil water content in the root zone, with error of estimation equal to about 2.0%. These differences can be considered acceptable for practical applications taking into account the intrinsic variability of the data especially in the soil moisture point measurements. An error less than 1 mm was calculated in the daily transpiration estimation. A good performance was observed in the estimation of the cumulate transpiration fluxes.

Loss of surface horizon of an irrigated soil detected by radiometric images of normalized difference vegetation index.

NASA Astrophysics Data System (ADS)

Fabian Sallesses, Leonardo; Aparicio, Virginia Carolina; Costa, Jose Luis

2017-04-01

The use of the soil in the Humid Pampa of Argentina has changed since the mid-1990s from agricultural-livestock production (that included pastures with direct grazing) to a purely agricultural production. Also, in recent years the area under irrigation by central pivot has been increased to 150%. The waters used for irrigation are sodium carbonates. The combination of irrigation and rain increases the sodium absorption ratio of soil (SARs), consequently raising the clay dispersion and reducing infiltration. This implies an increased risk of soil loss. A reduction in the development of white clover crop (Trifolium repens L.) was observed at an irrigation plot during 2015 campaign. The clover was planted in order to reduce the impact of two maize (Zea mays L.) campaigns under irrigation, which had increased soil SAR and deteriorated soil structure. SPOT-5 radiometric normalized difference vegetation index (NDVI) images were used to determine two zones of high and low production. In each zone, four random points were selected for further geo-referenced field sampling. Two geo-referenced measures of effective depth and surface soil sampling were carried out in each point. Texture of soil samples was determined by Pipette Method of Sedimentation Analysis. Data exploratory analysis showed that low production zone had a media effective depth = 80 cm and silty clay loam texture, while high production zone had a media effective depth > 140 cm and silt loam texture. The texture class of the low production zone did not correspond to prior soil studies carried out by the INTA (National Institute of Agricultural Technology), which showed that those soil textures were silt loam at surface and silty clay loam at sub-surface. The loss of the A horizon is proposed as a possible explanation, but further research is required. Besides, the need of a soil cartography actualization, which integrates new satellite imaging technologies and geo-referenced measurements with soil sensors is emphasized. Key words: soil use change, satellite images, erosion.

Chemomechanical preparation by hand instrumentation and by Mtwo engine-driven rotary files, an ex vivo study.

PubMed

Krajczár, Károly; Tigyi, Zoltán; Papp, Viktória; Marada, Gyula; Sára, Jeges; Tóth, Vilmos

2012-07-01

To compare the disinfecting efficacy of the sodium hypochlorite irrigation by root canal preparation with stainless steel hand files, taper 0.02 and nickel-titanium Mtwo files with taper 0.04-0.06. 40 extracted human teeth were sterilized, and then inoculated with Enterococcus faecalis (ATCC 29212). After 6 day incubation time the root canals were prepared by hand with K-files (n=20) and by engine-driven Mtwo files (VDW, Munich, Germany) (n=20). Irrigation was carried out with 2.5% NaOCl in both cases. Samples were taken and determined in colony forming units (CFU) from the root canals before and after the preparation with instruments #25 and #35. Significant reduction in bacterial count was determined after filing at both groups. The number of bacteria kept on decreasing with the extension of apical preparation diameter. There was no significant difference between the preparation sizes in the bacterial counts after hand or engine-driven instrumentation at the same apical size. Statistical analysis was carried out with Mann-Whitney test, paired t-test and independent sample t-test. Significant reduction in CFU was achieved after the root canal preparation completed with 2.5% NaOCl irrigation, both with stainless steel hand or nickel-titanium rotary files. The root canal remained slightly infected after chemo mechanical preparation in both groups. Key words:Chemomechanical preparation, root canal disinfection, nickel-titanium, conicity, greater taper, apical size.

Chemomechanical preparation by hand instrumentation and by Mtwo engine-driven rotary files, an ex vivo study

PubMed Central

Krajczár, Károly; Tigyi, Zoltán; Papp, Viktória; Sára, Jeges; Tóth, Vilmos

2012-01-01

Objective: To compare the disinfecting efficacy of the sodium hypochlorite irrigation by root canal preparation with stainless steel hand files, taper 0.02 and nickel-titanium Mtwo files with taper 0.04-0.06. Study Design: 40 extracted human teeth were sterilized, and then inoculated with Enterococcus faecalis (ATCC 29212). After 6 day incubation time the root canals were prepared by hand with K-files (n=20) and by engine-driven Mtwo files (VDW, Munich, Germany) (n=20). Irrigation was carried out with 2.5% NaOCl in both cases. Samples were taken and determined in colony forming units (CFU) from the root canals before and after the preparation with instruments #25 and #35. Results: Significant reduction in bacterial count was determined after filing at both groups. The number of bacteria kept on decreasing with the extension of apical preparation diameter. There was no significant difference between the preparation sizes in the bacterial counts after hand or engine-driven instrumentation at the same apical size. Statistical analysis was carried out with Mann-Whitney test, paired t-test and independent sample t-test. Conclusions: Significant reduction in CFU was achieved after the root canal preparation completed with 2.5% NaOCl irrigation, both with stainless steel hand or nickel-titanium rotary files. The root canal remained slightly infected after chemo mechanical preparation in both groups. Key words:Chemomechanical preparation, root canal disinfection, nickel-titanium, conicity, greater taper, apical size. PMID:24558545

Effect of super-oxidized water, sodium hypochlorite and EDTA on dentin microhardness.

PubMed

Ghisi, Alexandre Corrêa; Kopper, Patrícia Maria Poli; Baldasso, Flávia E R; Stürmer, Caroline P; Rossi-Fedele, Giampiero; Steier, Liviu; Figueiredo, José Antonio Poli de; Morgental, Renata Dornelles; Vier-Pelisser, Fabiana Vieira

2014-01-01

The present study aimed to evaluate the influence of the following irrigating solutions on the microhardness of root canal dentin: 2% sodium hypochlorite (2NaOCl), 5% sodium hypochlorite (5NaOCl), super-oxidized water (400 ppm Sterilox - Sx) and 17% EDTA (E). Eighty roots from bovine incisors were randomly divided into 8 groups (n=10): 2NaOCl, 5NaOCl, Sx, and 2NaOCl + E, 5NaOCl + E, Sx + E (associated with E as final irrigant for 5 min), E solely and distilled water (dH2O) as the negative control. Root canal preparation was performed by hand instruments, using one of the irrigation protocols for 30 min. Then, 5 mm of the cervical root third were cut out from each sample and subjected to the Vickers microhardness test, at two points, one at approximately 500-1000 µm from the root canal lumen (distance 1), and the other at approximately 500-1000 µm from the external root surface (distance 2). Data were analyzed by Wilcoxon and Kruskal-Wallis tests at 5% significance level. Microhardness values at distance 1 were significantly lower than those at distance 2 for all groups, except 5NaOCl and 5NaOCl + E groups (p>0.05). EDTA showed the lowest microhardness values. However, no statistically significant difference was detected among groups at distance 1 and EDTA was significantly different only from Sx at distance 2. In conclusion, all tested solutions showed lower microhardness at the most superficial root canal dentin layer compared to the one found near the external root surface, except 5NaOCl and 5NaOCl + E; EDTA promoted lower microhardness values in comparison to Sterilox at this site.

[Spatial and temporal characteristics of flue-cured tobacco water requirement and irrigation requirement index in Yunnan Province, China].

PubMed

Zheng, Dong-fang; Xu, Jia-yang; Lu, Xiu-ping; Xu, Zi-cheng; Li, Jun-ying; Pang, Tao; Zhang, Ya-jie; Wang, Pei-wen

2015-07-01

Based on the daily meteorological data of 124 agricultural meteorological sites during 1977-2010 in Yunnan Province, using recommended Penman-Monteith formula by FAO, water requirement and irrigation requirement index in the growth period of flue-cured tobacco were calculated to analyze their spatial and temporal characteristics and change patterns. The results showed that water requirements of flue-cured tobacco in root extending, vigorous, mature periods and field growth period during 1977-2010 were 76.73-174.73, 247.50-386.64, 180.28-258.14 and 528.18-764.08 mm, respectively, and the water requirement of vigorous period was the highest. The average irrigation demand index of each period was -0.02, 0.38, 0.17 and 0.26, respectively. Effective precipitation could meet the demand of flue-cured tobacco in root extending period. Water requirement of flue-cured tobacco in Yunnan Province decreased annually, and the rates of water requirement under the climate change trend in the four periods abovementioned were -12. 42, -21.46, -7.17 and -47.15 mm . (10 a)-1, respectively. The smallest irrigation demand index was observed in Dehong, and the largest in Diqing. The irrigation demand indexes of Dehong, Xishuangbanna and Puer regions were negative in flue-cured tobacco field growth period. The reference crop evapotranspiration, water requirement and effective precipitation decreased, but the irrigation requirement and irrigation requirement index increased with the increase of latitude. The effective precipitation decreased, but the irrigation requirement and irrigation requirement index increased with the increase of altitude.

In vitro comparison of passive and continuous ultrasonic irrigation in simulated lateral canals of extracted teeth.

PubMed

Castelo-Baz, Pablo; Martín-Biedma, Benjamín; Cantatore, Giuseppe; Ruíz-Piñón, Manuel; Bahillo, José; Rivas-Mundiña, Berta; Varela-Patiño, Purificación

2012-05-01

Complete endodontic system disinfection requires the removal of vital and necrotic pulp tissue, microorganisms, and toxins. The purpose of this study was to compare the effects of 2 ultrasonic irrigation techniques on the penetration of sodium hypochlorite into the main canal and simulated lateral canals of extracted teeth. Two simulated lateral canals each were created 2, 4, and 6 mm from the working length in 60 single-rooted teeth (6 canals/tooth, n = 360). To resemble the clinical situation, a closed system was created in each tooth. The teeth were randomly assigned to 3 experimental irrigation groups: group 1 (n = 20), positive pressure irrigation (PPI); group 2 (n = 20), passive ultrasonic irrigation (PUI); and group 3 (n = 20), continuous ultrasonic irrigation (CUI). Samples were evaluated by direct observation of still images recorded under a dental operating microscope. To examine irrigating solution penetration, 20% Chinese ink (Sanford Rotring GmbH, Hamburg, Germany) was added to a 5% sodium hypochlorite solution and delivered into the root canals. The results showed a significantly higher (P < .05) penetration of irrigant into the lateral canals in the CUI group. PUI and CUI did not differ significantly in solution penetration into the apical thirds of the main canals. The PPI group showed a significantly lower penetration of sodium hypochlorite into the main and lateral canals compared with the CUI and PUI groups. CUI as a final rinse significantly increased the penetration of irrigating solution into simulated lateral canals. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Evaluation of apical extrusion of debris and irrigant using two new reciprocating and one continuous rotation single file systems.

PubMed

Nayak, Gurudutt; Singh, Inderpreet; Shetty, Shashit; Dahiya, Surya

2014-05-01

Apical extrusion of debris and irrigants during cleaning and shaping of the root canal is one of the main causes of periapical inflammation and postoperative flare-ups. The purpose of this study was to quantitatively measure the amount of debris and irrigants extruded apically in single rooted canals using two reciprocating and one rotary single file nickel-titanium instrumentation systems. Sixty human mandibular premolars, randomly assigned to three groups (n = 20) were instrumented using two reciprocating (Reciproc and Wave One) and one rotary (One Shape) single-file nickel-titanium systems. Bidistilled water was used as irrigant with traditional needle irrigation delivery system. Eppendorf tubes were used as test apparatus for collection of debris and irrigant. The volume of extruded irrigant was collected and quantified via 0.1-mL increment measure supplied on the disposable plastic insulin syringe. The liquid inside the tubes was dried and the mean weight of debris was assessed using an electronic microbalance. The data were statistically analysed using Kruskal-Wallis nonparametric test and Mann Whitney U test with Bonferroni adjustment. P-values less than 0.05 were considered significant. The Reciproc file system produced significantly more debris compared with OneShape file system (P<0.05), but no statistically significant difference was obtained between the two reciprocating instruments (P>0.05). Extrusion of irrigant was statistically insignificant irrespective of the instrument or instrumentation technique used (P >0.05). Although all systems caused apical extrusion of debris and irrigant, continuous rotary instrumentation was associated with less extrusion as compared with the use of reciprocating file systems.

Antibacterial and residual antimicrobial activities against Enterococcus faecalis biofilm: A comparison between EDTA, chlorhexidine, cetrimide, MTAD and QMix

NASA Astrophysics Data System (ADS)

Zhang, Rui; Chen, Min; Lu, Yan; Guo, Xiangjun; Qiao, Feng; Wu, Ligeng

2015-08-01

We compared the antibacterial and residual antimicrobial activities of five root canal irrigants (17% EDTA,2% chlorhexidine,0.2% cetrimide, MTAD, and QMix) in a model of Enterococcus faecalis biofilm formation. Sixty dentin blocks with 3-week E. faecalis biofilm were divided into six equal groups and flushed with irrigant for 2 min or left untreated. A blank control group was also established. Antibacterial activities of the irrigants were evaluated by counting colony forming units. To test residual antimicrobial activities, 280 dentin blocks were divided into seven equal groups and flushed with irrigant for 2 min or left untreated and then incubated with E. faecalis suspension for 48 h, or used as a blank. No bacteria were observed in the blank control group. The number of viable E. faecalis was significantly fewer in the irrigant-treated groups compared with the untreated control (P < 0.05). Among the five irrigants, QMix had the strongest antibacterial activity. Residual antimicrobial activities of CHX were significantly higher at 12 h, 24 h and 36 h compared to untreated control (P < 0.05). All five root canal irrigants were effective to some extent against E. faecalis, but QMix and CHX had the strongest, and CHX the longest (up to 36 h), antimicrobial activity.

The efficacy of the self-adjusting file and ProTaper for removal of calcium hydroxide from root canals

PubMed Central

FARIA, Gisele; KUGA, Milton Carlos; RUY, Alessandra Camila; ARANDA-GARCIA, Arturo Javier; BONETTI-FILHO, Idomeo; GUERREIRO-TANOMARU, Juliane Maria; LEONARDO, Renato Toledo

2013-01-01

Objective The goal of this study was to evaluate the efficacy of the Self-Adjusting File (SAF) and ProTaper for removing calcium hydroxide [Ca(OH)2] from root canals. Material and Methods Thirty-six human mandibular incisors were instrumented with the ProTaper system up to instrument F2 and filled with a Ca(OH)2-based dressing. After 7 days, specimens were distributed in two groups (n=15) according to the method of Ca(OH)2 removal. Group I (SAF) was irrigated with 5 mL of NaOCl and SAF was used for 30 seconds under constant irrigation with 5 mL of NaOCl using the Vatea irrigation device, followed by irrigation with 3 mL of EDTA and 5 mL of NaOCl. Group II (ProTaper) was irrigated with 5 mL of NaOCl, the F2 instrument was used for 30 seconds, followed by irrigation with 5 mL of NaOCl, 3 mL of EDTA, and 5 mL of NaOCl. In 3 teeth Ca(OH)2 was not removed (positive control) and in 3 teeth canals were not filled with Ca(OH)2 (negative control). Teeth were sectioned and prepared for the scanning electron microscopy. The amounts of residual Ca(OH)2 were evaluated in the middle and apical thirds using a 5-score system. Results None of the techniques completely removed the Ca(OH)2 dressing. No difference was observed between SAF and ProTaper in removing Ca(OH)2 in the middle (P=0.11) and the apical (P=0.23) thirds. Conclusion The SAF system showed similar efficacy to rotary instrument for removal of Ca(OH)2 from mandibular incisor root canals. PMID:24037074

Assessment of irrigation performance: contribution to improve water management in a small catchment in the Brazilian savannas

NASA Astrophysics Data System (ADS)

Rodrigues, Lineu; Marioti, Juliana; Steenhuis, Tammo; Wallender, Wesley

2010-05-01

Irrigated agriculture is the major consumer of surface water in Brazil using over 70% of the total supply. Due to the growing competition for water among different sectors of the economy, sustainable water use can only be achieved by decreasing the portion of water used by the irrigated agriculture. Thus, in order to maintain yield, farmers need to irrigate more efficiently. There is little known on irrigation efficiency in Brazil. Therefore a study was carried out in the Buriti Vermelho basin to assess the irrigation performance of existing system. The experimental basin has a drainage area of 940 hectares and is located in the eastern part of the Federal District, in the Brazilian savanna region. Agriculture is the main activity. There is a dominance of red latosols. Several types of land use and crop cover are encountered in the basin. Conflicts among farmers for water are increasing. As water, in quality and quantity, is crucial to maintain the livelihood of the population in the basin, concern about risk of water lack due to climatic and land use change is in place. Once irrigation is the main water user in the basin, to increase water availability and reduce conflicts a water resource management plan has to be established. For this purpose, irrigation system performance has to be understood. The objective of this work was to assess the performance and the management of irrigation (small and big) that has been carried out by farmers in the Buriti Vermelho experimental watershed. A survey undertaken in 2007 was used to identify the irrigation systems in the basin. It was verified that irrigation is practiced by both small (area up to 6 hectare) and big farmers. Small farmers usually crop limes and vegetables and use micro-irrigation, drip, sprinkler, guns or furrow to irrigate them. Big farmers plant annual crops and use center pivot as irrigation system. In this first assessment 13 irrigation systems were evaluated: five conventional sprinklers, four drip systems, one microirrigation system and three center pivots schemes. Field evaluations used the method advocated by Keller and Bliesner and conducted during farmer scheduled irrigation. Soil samples were taken before irrigations to investigate adequacy of water applied. Since the irrigation water management and the uniformity of water distribution are the two major factors used to define the quality of irrigation, the following criteria for uniformity was used: i) Localized irrigations (distribution uniformity - UD) - excellent (90% < UD), acceptable (70% < UD < 90%), not acceptable (UD < 70); ii) Center pivots and conventional sprinkler irrigations (Christiansen coefficient - UC) - excellent (85% < UC), acceptable (85% < UC < 75%), not acceptable (UC < 75%). The water stored in the root zone after an irrigation event was compared with the real necessity. The results showed that: i) Localized irrigations - Three systems had UD < 70% and all systems presented deficit or excess of irrigation; ii) Conventional sprinkler system - Three system had UD smaller than 75% and all systems applied less water than the minimum necessary to keep an amount of water in the soil that don't cause plant stress; iii) Center pivot - In two system were observed UC < 75%. In one of the center pivots the depth applied was about 42% higher than the required and in the other two it was 39% and 47% lower. The study demonstrated the importance of adopting irrigation management criteria, in agricultural basins, once irrigation water becomes limiting and reduces basin water productivity.

Inoculation of drought-stressed strawberry with a mixed inoculum of two arbuscular mycorrhizal fungi: effects on population dynamics of fungal species in roots and consequential plant tolerance to water deficiency.

PubMed

Boyer, Louisa Robinson; Brain, Philip; Xu, Xiang-Ming; Jeffries, Peter

2015-04-01

The effect of inoculation with two arbuscular mycorrhizal fungi (AMF) on growth and drought tolerance of cultivated strawberry (Fragaria × ananassa) was studied. Three treatments (a single treatment either of Funneliformis mosseae BEG25, Funneliformis geosporus BEG11 or a 50:50 mixed inoculation treatment of both species) were compared to uninoculated plants. Species-specific primers for qPCR quantification of F. geosporus and F. mosseae DNA were developed to quantify the relative abundance of each fungus in roots of strawberry under different conditions of water stress. Co-occupation of the same root by both species was shown to commonly occur, but their relative abundance varied with water stress (reduced irrigation of up to 40%). Greater root colonisation was observed microscopically under water stress, but this increased colonisation was often accompanied with decreased amounts of fungal DNA in the root. F. mosseae tended to become more abundant under water stress relative to F. geosporus. There was significant correlation in the fungal colonisation measurements from the microscopic and qPCR methods under some conditions, but the nature of this relationship varied greatly with AMF inoculum and abiotic conditions. Single-species inoculation treatments gave similar benefits to the host to the mixed inoculation treatment regardless of irrigation regime; here, amount of colonisation was of greater importance than functional diversity. The addition of AMF inocula to plants subjected to reduced irrigation restored plant growth to the same or higher values as the non-mycorrhizal, fully-watered plants. The water use efficiency of plants was greater under the regulated deficit irrigation (RDI) regime and in AMF-inoculated plants, but there were no significant differences between plants inoculated with the single or combined inoculum. This study demonstrated that the increase in plant growth was directly influenced by an increase in root colonisation by AMF when individual plants were examined.

Influence of different irrigation levels on the root water uptake and the physiology of root-chicory

NASA Astrophysics Data System (ADS)

Vandoorne, B.; Dekoninck, N.; Lutts, S.; Capelle, B.; Javaux, M.

2009-04-01

In the context of global warming and given recent heat waves observed in Western Europe, the relationship between the soil water status and the plant health has recently received more attention, especially for cash crops like chicory. In this study we particularly investigated the impact of soil water status on the chicory root water uptake and density and made a link with physiological and yield parameters. During five months, we imposed different irrigation levels to 10 plants of chicory (Cichorium intybus var. sativum) growing in greenhouses. Each seed, coming from an autogamous selection in this allogamous species, was sown in a column of 1.42m height and 0.4m diameter filled with yellow sand and irrigated from the bottom with Hoagland solution. On those 10 columns, we measured the distribution of soil moisture with TDR (8 columns) and ERT (2 columns) probes. Lateral windows also allowed us to follow the root growth. The column weights were also monitored in order to quantify the plant transpiration. During the experiment, several physiological indices were also followed like the gas exchange (CO2 and transpiration), the chlorophyll fluorescence, the stomatal conductance, the plastochron, and the Leaf Area Index (LAI). At the end of the experiment, the complete root length density and the water content profiles were measured. We had also a look to the osmotic potential, the pigments content and the isotopic discrimination of carbon in the leaves, which gives information about the level of stress. At a biochemical point of view, we measured the content in enzymes involves in inulin metabolism and sugars synthesis. We observed that the plants suffering from a slight water stress developed better. A simple1-D model was built which describes the root growth in function of the irrigation level and of the soil and atmospheric boundary conditions.

Concentration and time-dependent effect of initial sodium hypochlorite on the ability of QMix and ethylenediaminetetraacetic acid to remove smear layer.

PubMed

Aksel, Hacer; Serper, Ahmet

2017-01-01

The aim of this study was to compare the ability of 17% ethylenediaminetetraacetic acid (EDTA) and QMix with different concentrations and time exposures of initial sodium hypochlorite (NaOCl) to remove the smear layer from the root canals. Eighty maxillary central incisors were used. After instrumentation, the teeth were divided into eight experimental groups according to the initial and final rinse. About 2.5% and 5% NaOCl were used during instrumentation and for 1 or 3 min was used as postinstrumentation initial irrigants, and 17% EDTA and QMix used as final irrigants. The apical and middle parts of the specimens were observed by scanning electron microscope. Data were analyzed using the Kruskal-Wallis, Mann-Whitney, and Friedman's test. Regardless of the type of final irrigant, QMix allowed more smear layer removal than EDTA after using 5% initial NaOCl for 3 min. In the apical part of the root canal walls, the smear layer was not completely removed. QMix and EDTA were similarly effective in smear layer removal at the middle parts of the root canal regardless of the concentration and time exposure of initial NaOCl, while none of the irrigation protocols was able to remove smear layer at the apical parts.

Wall shear stress effects of different endodontic irrigation techniques and systems.

PubMed

Goode, Narisa; Khan, Sara; Eid, Ashraf A; Niu, Li-na; Gosier, Johnny; Susin, Lisiane F; Pashley, David H; Tay, Franklin R

2013-07-01

This study examined débridement efficacy as a result of wall shear stresses created by different irrigant delivery/agitation techniques in an inaccessible recess of a curved root canal model. A reusable, curved canal cavity containing a simulated canal fin was milled into mirrored titanium blocks. Calcium hydroxide (Ca(OH)2) paste was used as debris and loaded into the canal fin. The titanium blocks were bolted together to provide a fluid-tight seal. Sodium hypochlorite was delivered at a previously-determined flow rate of 1 mL/min that produced either negligible or no irrigant extrusion pressure into the periapex for all the techniques examined. Nine irrigation delivery/agitation techniques were examined: NaviTip passive irrigation control, Max-i-Probe(®) side-vented needle passive irrigation, manual dynamic agitation (MDA) using non-fitting and well-fitting gutta-percha points, EndoActivator™ sonic agitation with medium and large points, VPro™ EndoSafe™ irrigation system, VPro™ StreamClean™ continuous ultrasonic irrigation and EndoVac apical negative pressure irrigation. Débridement efficacies were analysed with Kruskal-Wallis ANOVA and Dunn's multiple comparisons tests (α=0.05). EndoVac was the only technique that removed more than 99% calcium hydroxide debris from the canal fin at the predefined flow rate. This group was significantly different (p<0.05) from the other groups that exhibited incomplete Ca(OH)2 removal. The ability of the EndoVac system to significantly clean more debris from a mechanically inaccessible recess of the model curved root canal may be caused by robust bubble formation during irrigant delivery, creating higher wall shear stresses by a two-phase air-liquid flow phenomenon that is well known in other industrial débridement systems. Copyright © 2013 Elsevier Ltd. All rights reserved.

Agricultural Liming, Irrigation, and Carbon Sequestration

NASA Astrophysics Data System (ADS)

McGill, B. M.; Hamilton, S. K.

2015-12-01

Row crop farmers routinely add inorganic carbon to soils in the form of crushed lime (e.g., calcite or dolomite minerals) and/or inadvertently as bicarbonate alkalinity naturally dissolved in groundwater used for irrigation. In the soil these carbonates can act as either a source or sink of carbon dioxide, depending in large part on nitrogen fertilization and nitrification. The potentially variable fate of lime carbon is not accounted for in the IPCC greenhouse gas inventory model for lime emissions, which assumes that all lime carbon becomes carbon dioxide (irrigation additions are not accounted for). In a corn-soybean-wheat crop rotation at the Kellogg Biological Station Long Term Ecological Research site in southwest Michigan, we are collecting soil porewater from several depths in the vadose zone across a nitrogen fertilizer gradient with and without groundwater irrigation. The soil profile in this region is dominated by carbonate rich glacial outwash that lies 1.5 m below a carbonate-leached zone. We analyze the porewater stoichiometry of calcium, magnesium, and carbonate alkalinity in a conceptual model to reveal the source/sink fate of inorganic carbon. High nitrate porewater concentrations are associated with net carbon dioxide production in the carbonate-leached zone, according to our model. This suggests that the acidity associated with nitrification of the nitrogen fertilizer, which is evident from soil pH measurements, is driving the ultimate fate of lime carbon in the vadose zone. Irrigation is a significant source of both alkalinity and nitrate in drier years, compared to normal rates of liming and fertilization. We will also explore the observed dramatic changes in porewater chemistry and the relationship between irrigation and inorganic carbon fate above and within the native carbonate layer.

Effect of Alcohol on the Spreading Ability of Sodium Hypochlorite Endodontic Irrigant

DTIC Science & Technology

1982-09-01

Research Progress Sodium Hypochlorite Endodontic Irrigant Report (Interim) 6. PERFORMING ORG. REPORT NUMBER 7. AU THOR(s) 8. CONTRACT OR GRANT NUMBER(s...neceewary and Identify by block nam.ber) Alcohol Sodium hypochlorite Endodontics Root canal 20, ABSTRACT (Continue on reveree side If neceeseay and...depressant significantly increased the ability of the sodium hypochlorite endodontic irrigant to penetrate in vitro. A freshly mixed solution containing 30

Uptake of macro- and micro-nutrients into leaf, woody, and root tissue of Populus after irrigation with landfill leachate

Treesearch

Jill A. Zalesny; Ronald S., Jr. Zalesny; Adam H. Wiese; Bart T. Sexton; Richard B. Hall

2008-01-01

Information about macro- and micro-nutrient uptake and distribution into tissues of Populus irrigated with landfill leachate helps to maximize biomass production and understand impacts of leachate chemistry on tree health. We irrigated eight Populus clones (NC 13460, NCI4O18, NC14104, NC14106, DM115, DN5, NM2, NM6) with fertilized (N, P, K) well...

Foliar uptake of radiocaesium from irrigation water by paddy rice (Oryza sativa): an overlooked pathway in contaminated environments.

PubMed

Uematsu, Shinichiro; Vandenhove, Hildegarde; Sweeck, Lieve; Hees, May Van; Wannijn, Jean; Smolders, Erik

2017-04-01

Flooded (paddy) rice (Oryza sativa) can take up ions from the irrigation water by foliar uptake via the exposed stem base. We hypothesised that the stem base uptake of radiocaesium (RCs) is a pathway for rice grown in RCs-contaminated environments. We developed a bi-compartmental device which discriminates the stem base from root RCs uptake from solutions, thereby using RCs isotopes ( 137 Cs and 134 Cs) with < 2% solution leak between the compartments. Radiocaesium uptake was linear over time (0-24 h). Radiocaesium uptake to the entire plant, expressed per dry weight of the exposed parts, was sixfold higher for the roots than for the exposed stem base. At equal RCs concentrations in both compartments, the exposed stem base and root uptake contributed almost equally to the total shoot RCs concentrations. Reducing potassium supply to the roots not only increased the root RCs uptake but also increased RCs uptake by the stem base. This study was the first to experimentally demonstrate active and internally regulated RCs uptake by the stem base of rice. Scenario calculations for the Fukushima-affected area predict that RCs in irrigation water could be an important source of RCs in rice as indirectly suggested from field data. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

The Use of Different Irrigation Techniques to Decrease Bacterial Loads in Healthy and Diabetic Patients with Asymptomatic Apical Periodontitis.

PubMed

Ghoneim, Mai; Saber, Shehab ElDin; El-Badry, Tarek; Obeid, Maram; Hassib, Nehal

2016-12-15

Diabetes mellitus is a multisystem disease which weakens the human's immunity. Subsequently, it worsens the sequelae of apical periodontitis by raising a fierce bacterial trait due to the impaired host response. This study aimed to estimate bacterial reduction after using different irrigation techniques in systemically healthy and diabetic patients with asymptomatic apical periodontitis. Enterococcus faecalis , Peptostreptococcus micros , and Fusobacterium necleatum bacteria were chosen, as they are the most common and prevailing strains found in periodontitis. Bacterial samples were retrieved from necrotic root canals of systemically healthy and diabetic patients, before and after endodontic cleaning and shaping by using two different irrigation techniques; the conventional one and the EndoVac system. Quantitive polymerase chain reaction (qPCR) was utilised to detect the reduction in the bacterial count. The EndoVac irrigation system was effective in reducing bacteria, especially Peptostreptococcus micros in the diabetic group when compared to conventional irrigation technique with a statistically significant difference. The EndoVac can be considered as a promising tool in combination with irrigant solution to defeat the bacterial colonies living in the root canal system. Additional studies ought to be done to improve the means of bacterial clearance mainly in immune-compromised individuals.

The Use of Different Irrigation Techniques to Decrease Bacterial Loads in Healthy and Diabetic Patients with Asymptomatic Apical Periodontitis

PubMed Central

Ghoneim, Mai; Saber, Shehab ElDin; El-Badry, Tarek; Obeid, Maram; Hassib, Nehal

2016-01-01

BACKGROUND: Diabetes mellitus is a multisystem disease which weakens the human’s immunity. Subsequently, it worsens the sequelae of apical periodontitis by raising a fierce bacterial trait due to the impaired host response. AIM: This study aimed to estimate bacterial reduction after using different irrigation techniques in systemically healthy and diabetic patients with asymptomatic apical periodontitis. MATERIAL AND METHODS: Enterococcus faecalis, Peptostreptococcus micros, and Fusobacterium necleatum bacteria were chosen, as they are the most common and prevailing strains found in periodontitis. Bacterial samples were retrieved from necrotic root canals of systemically healthy and diabetic patients, before and after endodontic cleaning and shaping by using two different irrigation techniques; the conventional one and the EndoVac system. Quantitive polymerase chain reaction (qPCR) was utilised to detect the reduction in the bacterial count. RESULTS: The EndoVac irrigation system was effective in reducing bacteria, especially Peptostreptococcus micros in the diabetic group when compared to conventional irrigation technique with a statistically significant difference. CONCLUSION: The EndoVac can be considered as a promising tool in combination with irrigant solution to defeat the bacterial colonies living in the root canal system. Additional studies ought to be done to improve the means of bacterial clearance mainly in immune-compromised individuals. PMID:28028421

Effect of apical size and taper on volume of irrigant delivered at working length with apical negative pressure at different root curvatures.

PubMed

de Gregorio, Cesar; Arias, Ana; Navarrete, Natalia; Del Rio, Veronica; Oltra, Enrique; Cohenca, Nestor

2013-01-01

The purpose of this investigation was to determine the effect that apical preparation size and preparation taper have on the volume of irrigant delivered at the working length for different canal curvatures using apical negative pressure irrigation. One hundred fifty-five human teeth (55 maxillary canines and 100 mandibular molars) were used in this study. Root canals were prepared with rotary instruments to a size 35.04 and separated into 3 experimental groups according to their degree of curvature: group A (n = 50) included canal curvatures ranging from 0° to 10°, group B (n = 50) from 11° to 30°, and group C (n = 50) from 31° to 65°. Samples of each curvature group were further randomized to experimental subgroups according to the apical size and taper as follow: 35.06, 40.04, 40.06, 45.04, and 45.06. The apical third was irrigated using a microcannula and the volume of NaOCl suctioned at the working length under negative pressure was measured over a period of 30 seconds using a fluid recovery trap. Positive controls consisted of measuring the maximum volume of 5.25% NaOCl capable of being suctioned by the microcannula from an open glass vial over 30 seconds. Negative control was the volume of irrigant aspirated by the microcannula with a preparation size of 25.04 over 30 seconds. The volume of irrigant was significantly greater when the apical preparation size increased from 35.06 to 40.04. As the apical preparation taper increased further from 40.04 to 40.06, the volume of irrigant significantly improved in group B, but it was not significant in group A. Apical preparation sizes greater than 40.06 did not show an increase of the volume of irrigant aspirated. The degree of root canal curvature decreased the volume of irrigant at the working length for a given apical size and taper. An apical preparation of 40.06 significantly increased the volume and exchange of irrigant at the working length regardless of curvature. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Efficacy of four different irrigation techniques combined with 60 °C 3% sodium hypochlorite and 17% EDTA in smear layer removal.

PubMed

Guo, Xiangjun; Miao, Hui; Li, Lei; Zhang, Shasha; Zhou, Dongyan; Lu, Yan; Wu, Ligeng

2014-09-08

Efforts to improve the efficacy of smear layer removal by applying irrigant activation at the final irrigation or by elevating the temperature of the irrigant have been reported. However, the combination of such activation protocols with 60 °C 3% sodium hypochlorite (NaOCl) has seldom been mentioned. The aim of this study was to compare the efficacy in smear layer removal of four different irrigation techniques combined with 60 °C 3% NaOCl and 17% EDTA. Fifty single-rooted teeth were randomly divided into five groups (n = 10) according to the irrigant agitation protocols used during chemomechanical preparation(Dentsply Maillefer, Ballaigues, Switzerland): a side-vented needle group, a ultrasonic irrigation (UI) group, a NaviTip FX group, an EndoActivator group, and a control group (no agitation). After each instrumentation, the root canals were irrigated with 1 mL of 3% NaOCl at 60 °C for 1 minute, and after the whole instrumentation, the root canals were rinsed with 1 mL of 17% EDTA for 1 minute. Both NaOCl and EDTA were activated with one of the five irrigation protocols. The efficacy of smear layer removal was scored at the apical, middle and coronal thirds. The Data were statistically analyzed using SAS version 9.2 for Windows (rank sum test for a randomised block design and ANOVA). No significant differences among the NaviTip FX group, EndoActivator group and control groups, and each of these groups showed a lower score than that of UI group (P < 0.05). Within each group, all three thirds were ranked in the following order: coronal > middle > apical (P < 0.05). In the coronal third, the NaviTip FX group was better than UI group. In the middle and apical third, the differences were not significant among any of the groups. Even without any activation, the combination of 60 °C 3% NaOCl and 17% EDTA could remove the smear layer effectively, similar to NaviTip FX or EndoActivator, and these three protocols were more effective than UI. However, regardless of different types of irrigation technique applied, complete removal of the smear layer was not achieved, particularly in the apical third.

Value added cleaning and disinfection of the root canal: laser-activated irrigation and laser-induced photoporation

NASA Astrophysics Data System (ADS)

De Moor, Roeland J. G.; Meire, Maarten A.

2016-03-01

Among present-day marketed systems ultrasonic activation appears to be the best way to activate and potentiate endodontic irrigants. An alternative for ultrasonic activation of irrigants is laser activated irrigation (LAI) or photoninitiated acoustic streaming. Based on present-day research it appears that LAI (especially with Erbium lasers) can be more efficient for debris removal out of root canals and interaction with the endodontic biofilms thanks to the induction of specific cavitation phenomena and acoustic streaming. Other wavelengths are now explored to be used for LAI. Another way to interact with biofilms is to rely on laser-induced photoporation in combination with gold nanoparticles ( AuNPs). The latter is an alternative physical method for delivering macromolecules in cells. Nanosized membrane pores can be created upon pulsed laser illumination. Depending on the laser energy, pores are created through either direct heating of the AuNPs or by vapour nanobubbles that can emerge around the AuNPs.

Effect of different irrigation on smear layer removal after post space preparation.

PubMed

Gu, Xin-Hua; Mao, Cai-Yun; Kern, Matthias

2009-04-01

The purpose of this study was to evaluate the effect of different irrigating solutions on smear layer removal and dentinal tubule opening on root canal surfaces after post space preparation and to study whether additional ultrasonic irrigation has any effect on smear layer removal. Forty-eight anterior teeth were treated endodontically. After post space preparation, they were assigned to six groups: group 1, EDTA; group 2, EDTA with ultrasonic activation; group 3, sodium hypochlorite (NaOCl); group 4, NaOCl with ultrasonic activation; group 5, sodium chloride (NaCl); and group 6, NaCl with ultrasonic activation. Specimens were examined under a field-emission scanning electron microscope and scored for debris removal and dentinal tubule opening at the coronal, middle, and apical thirds of the root canal. The results showed that EDTA performed significantly better than NaCl and NaOCl in smear layer removal and dentinal tubule opening. Additional ultrasonic irrigation did not improve smear layer removal significantly.

Nocturnal and daytime stomatal conductance respond to root-zone temperature in ‘Shiraz’ grapevines

PubMed Central

Rogiers, Suzy Y.; Clarke, Simon J.

2013-01-01

Background and Aims Daytime root-zone temperature may be a significant factor regulating water flux through plants. Water flux can also occur during the night but nocturnal stomatal response to environmental drivers such as root-zone temperature remains largely unknown. Methods Here nocturnal and daytime leaf gas exchange was quantified in ‘Shiraz’ grapevines (Vitis vinifera) exposed to three root-zone temperatures from budburst to fruit-set, for a total of 8 weeks in spring. Key Results Despite lower stomatal density, night-time stomatal conductance and transpiration rates were greater for plants grown in warm root-zones. Elevated root-zone temperature resulted in higher daytime stomatal conductance, transpiration and net assimilation rates across a range of leaf-to-air vapour pressure deficits, air temperatures and light levels. Intrinsic water-use efficiency was, however, lowest in those plants with warm root-zones. CO2 response curves of foliar gas exchange indicated that the maximum rate of electron transport and the maximum rate of Rubisco activity did not differ between the root-zone treatments, and therefore it was likely that the lower photosynthesis in cool root-zones was predominantly the result of a stomatal limitation. One week after discontinuation of the temperature treatments, gas exchange was similar between the plants, indicating a reversible physiological response to soil temperature. Conclusions In this anisohydric grapevine variety both night-time and daytime stomatal conductance were responsive to root-zone temperature. Because nocturnal transpiration has implications for overall plant water status, predictive climate change models using stomatal conductance will need to factor in this root-zone variable. PMID:23293018

Nocturnal and daytime stomatal conductance respond to root-zone temperature in 'Shiraz' grapevines.

PubMed

Rogiers, Suzy Y; Clarke, Simon J

2013-03-01

Daytime root-zone temperature may be a significant factor regulating water flux through plants. Water flux can also occur during the night but nocturnal stomatal response to environmental drivers such as root-zone temperature remains largely unknown. Here nocturnal and daytime leaf gas exchange was quantified in 'Shiraz' grapevines (Vitis vinifera) exposed to three root-zone temperatures from budburst to fruit-set, for a total of 8 weeks in spring. Despite lower stomatal density, night-time stomatal conductance and transpiration rates were greater for plants grown in warm root-zones. Elevated root-zone temperature resulted in higher daytime stomatal conductance, transpiration and net assimilation rates across a range of leaf-to-air vapour pressure deficits, air temperatures and light levels. Intrinsic water-use efficiency was, however, lowest in those plants with warm root-zones. CO(2) response curves of foliar gas exchange indicated that the maximum rate of electron transport and the maximum rate of Rubisco activity did not differ between the root-zone treatments, and therefore it was likely that the lower photosynthesis in cool root-zones was predominantly the result of a stomatal limitation. One week after discontinuation of the temperature treatments, gas exchange was similar between the plants, indicating a reversible physiological response to soil temperature. In this anisohydric grapevine variety both night-time and daytime stomatal conductance were responsive to root-zone temperature. Because nocturnal transpiration has implications for overall plant water status, predictive climate change models using stomatal conductance will need to factor in this root-zone variable.

Growth Chambers on the International Space Station for Large Plants

NASA Technical Reports Server (NTRS)

Massa, G. D.; Wheeler, R. M.; Morrow, R. C.; Levine, H. G.

2016-01-01

The International Space Station (ISS) now has platforms for conducting research on horticultural plant species under LED lighting, and those capabilities continue to expand. The 'Veggie' vegetable production system was deployed to the ISS as an applied research platform for food production in space. Veggie is capable of growing a wide array of horticultural crops. It was designed for low power usage, low launch mass and stowage volume, and minimal crew time requirements. The Veggie flight hardware consists of a light cap containing red (630 nm), blue, (455 nm) and green (530 nm) LEDs. Interfacing with the light cap is an extendable bellows/baseplate for enclosing the plant canopy. A second large plant growth chamber, the Advanced Plant Habitat (APH), is will fly to the ISS in 2017. APH will be a fully controllable environment for high-quality plant physiological research. APH will control light (quality, level, and timing), temperature, CO2, relative humidity, and irrigation, while scrubbing any cabin or plant-derived ethylene and other volatile organic compounds. Additional capabilities include sensing of leaf temperature and root zone moisture, root zone temperature, and oxygen concentration. The light cap will have red (630 nm), blue (450 nm), green (525 nm), far red (730 nm) and broad spectrum white LEDs (4100K). There will be several internal cameras (visible and IR) to monitor and record plant growth and operations. Veggie and APH are available for research proposals.

Efficacy of Needle, Ultrasonic, and Endoactivator Irrigation and Photon-Induced Photoacoustic Streaming in Removing Calcium Hydroxide from the Main Canal and Isthmus: An In Vitro Micro-Computed Tomography and Scanning Electron Microscopy Study.

PubMed

Li, Dongxia; Jiang, Shan; Yin, Xingzhe; Chang, Jeffrey Wen Wei; Ke, Jie; Zhang, Chengfei

2015-06-01

The aim of this in vitro study was to use high-resolution micro-computed tomography (micro-CT) and scanning electron microscopy (SEM) to compare the efficacy of four irrigation techniques [needle, ultrasonic, EndoActivator, and photon-induced photoacoustic streaming (PIPS)] in removing calcium hydroxide (Ca[OH]2) from the root canal and isthmus of maxillary premolars. Twenty-four maxillary first premolars were selected based on the presence of isthmus regions on micro-CT scans. Root canals were instrumented with an F2 file using ProTaper rotary instruments and filled with Ca(OH)2 paste. Samples were stored at 37°C and 100% humidity for 1 week and randomly divided into four groups (n=6 each), according to irrigation technique. Samples were scanned with micro-CT before instrumentation, after Ca(OH)2 filling, and after irrigation. Ca(OH)2 reduction in the coronal, middle, and apical thirds and in the isthmus were assessed with three-dimensional image analysis. Next, specimens were split longitudinally, and canal walls were examined with SEM for Ca(OH)2 residues. Data were statistically evaluated with the Kruskal-Wallis and Mann-Whitney tests (p=0.05). The PIPS and ultrasonic groups showed greater Ca(OH)2 reduction in the apical third and higher cleanliness of the isthmus than the EndoActivator and needle irrigation groups (p<0.05). Ca(OH)2 residue scores in the PIPS and ultrasonic groups were significantly lower than those in the EndoActivator and needle groups in all regions of the root canals (p<0.05). There was no significant difference between PIPS and ultrasonic groups (p>0.05), or between EndoActivator and needle groups (p>0.05). PIPS and ultrasonic irrigation more effectively removed Ca(OH)2 from the main canal and isthmus in maxillary premolars than did EndoActivator or needle irrigation.

Long-term trends in field level irrigation water demand in Mahanadi delta districts - a hydrological modeling approach for coping with climate change

NASA Astrophysics Data System (ADS)

Raju Pokkuluri, Venkat; Rao, Diwakar Parsi Guru; Hazra, Sugata; Srikant Kulkarni, Sunil

2017-04-01

India uses its 85 percent of available water resources for irrigation making it the country with largest net irrigated area in the world. With one of the largest delta plains, sustaining the needs of irrigation supplies is critical for food security and coping with challenges of climate change. The extensive development of upstream river basins/catchments is posing serious challenge and constrains to the water availability to delta regions, which depend on the controlled/regulated flows from the upstream catchments. The irrigation water demands vary due to changes in agricultural practices, cropping pattern and changing climate conditions. Estimation of realistic irrigation water demand and its trend over time is critical for meeting the supplementary water needs of productive agricultural lands in delta plains and there by coping the challenges of extensive upstream river basin development and climate change. The present study carried out in delta districts of Mahanadi river in Odisha State of India, wherein the long-term trends in field level irrigation water requirements were estimated, both on spatial & temporal scales, using hydrological modeling framework. This study attempts to estimate field level irrigation water requirements through simulation of soil water balance during the crop growing season through process based hydrological modeling framework. The soil water balance computations were carried out using FAO-56 framework, by modifying the crop coefficient (Kc) proportional to the water stress coefficient (Ks), which is a function of root zone depletion of water. Daily meteorological data, spatial cropping pattern, terrain are incorporated in the soil water balance simulation in the model. The irrigation water demand is derived considering the exclusion of soil water stress for each model time step. The field level irrigation water requirement at 8 day interval had been estimated for the each Rabi season (post-monsoon) spanning over 1986 to 2015. The results indicate that irrigation water requirements show spatial and temporal changes and tend to deviate from notional/envisaged demands. Validation of estimated irrigation demand is attempted through correlation of gap in supply and demand with the trends in crop water stress and crop production during the study years. Crop water Stress Index (CWSI), which is the ratio of deficit of actual evapotranspiration (AET) from the potential evapotranspiration (PET) and is derived from MODIS Evapotranspiration data. Agricultural production data is used from State/Central government statistics. The attempted methodology provides opportunities to estimate future irrigation water demand under projected climate change scenarios and for planning for basin level water resources development sustaining the delta agriculture, which are projected to be more vulnerable to climate change.

Dissecting the role of isoprene and stress-related hormones (ABA and ethylene) in Populus nigra exposed to unequal root zone water stress.

PubMed

Marino, Giovanni; Brunetti, Cecilia; Tattini, Massimiliano; Romano, Andrea; Biasioli, Franco; Tognetti, Roberto; Loreto, Francesco; Ferrini, Francesco; Centritto, Mauro

2017-12-01

Isoprene is synthesized through the 2-C-methylerythritol-5-phosphate (MEP) pathway that also produces abscisic acid (ABA). Increases in foliar free ABA concentration during drought induce stomatal closure and may also alter ethylene biosynthesis. We hypothesized a role of isoprene biosynthesis in protecting plants challenged by increasing water deficit, by influencing ABA production and ethylene evolution. We performed a split-root experiment on Populus nigra L. subjected to three water treatments: well-watered (WW) plants with both root sectors kept at pot capacity, plants with both root compartments allowed to dry for 5 days (DD) and plants with one-half of the roots irrigated to pot capacity, while the other half did not receive water (WD). WD and WW plants were similar in photosynthesis, water relations, foliar ABA concentration and isoprene emission, whereas these parameters were significantly affected in DD plants: leaf isoprene emission increased despite the fact that photosynthesis declined by 85% and the ABA-glucoside/free ABA ratio decreased significantly. Enhanced isoprene biosynthesis in water-stressed poplars may have contributed to sustaining leaf ABA biosynthesis by keeping the MEP pathway active. However, this enhancement in ABA was accompanied by no change in ethylene biosynthesis, likely confirming the antagonistic role between ABA and ethylene. These results may indicate a potential cross-talk among isoprene, ABA and ethylene under drought. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Nitrogen regulation of transpiration controls mass-flow acquisition of nutrients.

PubMed

Matimati, Ignatious; Verboom, G Anthony; Cramer, Michael D

2014-01-01

Transpiration may enhance mass-flow of nutrients to roots, especially in low-nutrient soils or where the root system is not extensively developed. Previous work suggested that nitrogen (N) may regulate mass-flow of nutrients. Experiments were conducted to determine whether N regulates water fluxes, and whether this regulation has a functional role in controlling the mass-flow of nutrients to roots. Phaseolus vulgaris were grown in troughs designed to create an N availability gradient by restricting roots from intercepting a slow-release N source, which was placed at one of six distances behind a 25 μm mesh from which nutrients could move by diffusion or mass-flow (termed 'mass-flow' treatment). Control plants had the N source supplied directly to their root zone so that N was available through interception, mass-flow, and diffusion (termed 'interception' treatment). 'Mass-flow' plants closest to the N source exhibited 2.9-fold higher transpiration (E), 2.6-fold higher stomatal conductance (gs), 1.2-fold higher intercellular [CO2] (Ci), and 3.4-fold lower water use efficiency than 'interception' plants, despite comparable values of photosynthetic rate (A). E, gs, and Ci first increased and then decreased with increasing distance from the N source to values even lower than those of 'interception' plants. 'Mass-flow' plants accumulated phosphorus and potassium, and had maximum concentrations at 10mm from the N source. Overall, N availability regulated transpiration-driven mass-flow of nutrients from substrate zones that were inaccessible to roots. Thus when water is available, mass-flow may partially substitute for root density in providing access to nutrients without incurring the costs of root extension, although the efficacy of mass-flow also depends on soil nutrient retention and hydraulic properties.

Nitrogen regulation of transpiration controls mass-flow acquisition of nutrients

PubMed Central

Matimati, Ignatious

2014-01-01

Transpiration may enhance mass-flow of nutrients to roots, especially in low-nutrient soils or where the root system is not extensively developed. Previous work suggested that nitrogen (N) may regulate mass-flow of nutrients. Experiments were conducted to determine whether N regulates water fluxes, and whether this regulation has a functional role in controlling the mass-flow of nutrients to roots. Phaseolus vulgaris were grown in troughs designed to create an N availability gradient by restricting roots from intercepting a slow-release N source, which was placed at one of six distances behind a 25 μm mesh from which nutrients could move by diffusion or mass-flow (termed ‘mass-flow’ treatment). Control plants had the N source supplied directly to their root zone so that N was available through interception, mass-flow, and diffusion (termed ‘interception’ treatment). ‘Mass-flow’ plants closest to the N source exhibited 2.9-fold higher transpiration (E), 2.6-fold higher stomatal conductance (g s), 1.2-fold higher intercellular [CO2] (C i), and 3.4-fold lower water use efficiency than ‘interception’ plants, despite comparable values of photosynthetic rate (A). E, g s, and C i first increased and then decreased with increasing distance from the N source to values even lower than those of ‘interception’ plants. ‘Mass-flow’ plants accumulated phosphorus and potassium, and had maximum concentrations at 10mm from the N source. Overall, N availability regulated transpiration-driven mass-flow of nutrients from substrate zones that were inaccessible to roots. Thus when water is available, mass-flow may partially substitute for root density in providing access to nutrients without incurring the costs of root extension, although the efficacy of mass-flow also depends on soil nutrient retention and hydraulic properties. PMID:24231035

Comparative evaluation of canal isthmus debridement efficacy of modified EndoVac technique with different irrigation systems.

PubMed

Thomas, Anchu Rachel; Velmurugan, Natanasabapathy; Smita, Surendran; Jothilatha, Sundaramurthy

2014-10-01

The purpose of this study was to evaluate the canal isthmus debridement efficacy of a new modified EndoVac (Discus Dental, Culver City, CA) irrigation protocol in comparison with EndoVac, passive ultrasonic irrigation (PUI), and conventional needle irrigation in mesial roots of mandibular molars. The mesial roots of 64 extracted mandibular molars mounted in resin using Kuttler's endodontic cube, sectioned at 2 and 4 mm from the working length, were randomly divided into 4 groups (n = 16): group 1: Max-I-Probe (Dentsply Tulsa Dental, York, PA), group 2: EndoVac (EVI), group 3: modified EndoVac, and group 4: PUI. The specimens were reassembled and instrumented. A standard irrigation protocol was used during cleaning and shaping and final irrigation with the 4 irrigation/agitation techniques. Images of the isthmus region were taken before and after cleaning and shaping and after final irrigation. The percentage reduction of debris in the isthmus region was calculated by using the software program Image J (v1.43; National Institutes of Health, Bethesda, MD). Intergroup analysis was performed using the Kruskal Wallis and Mann-Whitney U tests. Intragroup analysis was performed using Friedman and Wilcoxon signed rank tests. The level of significance was set at P < .05. Intragroup analysis revealed a statistically significant difference in the percentage reduction of debris after cleaning and shaping and after final irrigation protocol in all the groups (P < .001). The final irrigation protocol produced significantly cleaner canal isthmuses in all the groups (P < .001). On intergroup analysis, the modified EVI group performed significantly better than the other groups. The EVI and PUI groups performed better than the Max-I-Probe group. There was no statistical significance between the EVI and PUI groups. Canal isthmuses were significantly cleaner with the modified EndoVac irrigation technique when compared with the cleanliness seen with the other irrigation systems. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Effect of photon-initiated photoacoustic streaming, passive ultrasonic, and sonic irrigation techniques on dentinal tubule penetration of irrigation solution: a confocal microscopic study.

PubMed

Akcay, Merve; Arslan, Hakan; Mese, Merve; Durmus, Nazlı; Capar, Ismail Davut

2017-09-01

The aim of this in vitro study was to evaluate the efficacy of different irrigation techniques including laser-activated irrigation using an erbium:yttrium-aluminum-garnet (Er:YAG) laser with a novel tip design (photon-induced photoacoustic streaming (PIPS)), Er:YAG laser with Preciso tip, sonic activation, and passive ultrasonic activation on the final irrigation solution penetration into dentinal tubules by using a laser scanning confocal microscope. In this study, 65 extracted single-rooted human mandibular premolars were instrumented up to size 40 and randomly divided into 5 groups (n = 13) based on the activation technique of the final irrigation solution as follows: conventional irrigation (control group), sonic activation, passive ultrasonic activation, Er:YAG-PIPS tip activation, and Er:YAG-Preciso tip activation. In each group, 5 mL of 5% NaOCl labeled with fluorescent dye was used during the activation as the final irrigation solution. Specimens were sectioned at 2.5 and 8 mm from the apex and then examined under a confocal microscope to calculate the dentinal tubule penetration area. Data were analyzed using two-way analysis of variance (ANOVA) and Tukey's post hoc tests (P = 0.05). Both Er:YAG laser (Preciso/PIPS) activations exhibited a significantly higher penetration area than the other groups (P < 0.05). Additionally, passive ultrasonic activation had significantly higher penetration than the sonic activation group and the control group. Statistically significant differences were also found between each root canal third (coronal > middle > apical) (P < 0.001). The results from the present study support the use of Er:YAG laser activation (Preciso/PIPS) to improve the effectiveness of the final irrigation procedure by increasing the irrigant penetration area into the dentinal tubules. The activation of the irrigant and the creation of the streaming with the Er:YAG laser have a positive effect on the irrigant penetration.

Microbial community structure across a wastewater-impacted riparian buffer zone in the southeastern coastal plain.

PubMed

Ducey, T F; Johnson, P R; Shriner, A D; Matheny, T A; Hunt, P G

2013-01-01

Riparian buffer zones are important for both natural and developed ecosystems throughout the world because of their ability to retain nutrients, prevent soil erosion, protect aquatic environments from excessive sedimentation, and filter pollutants. Despite their importance, the microbial community structures of riparian buffer zones remains poorly defined. Our objectives for this study were twofold: first, to characterize the microbial populations found in riparian buffer zone soils; and second, to determine if microbial community structure could be linked to denitrification enzyme activity (DEA). To achieve these objectives, we investigated the microbial populations of a riparian buffer zone located downslope of a pasture irrigated with swine lagoon effluent, utilizing DNA sequencing of the 16S rDNA, DEA, and quantitative PCR (qPCR) of the denitrification genes nirK, nirS, and nosZ. Clone libraries of the 16S rDNA gene were generated from each of twelve sites across the riparian buffer with a total of 986 partial sequences grouped into 654 operational taxonomic units (OTUs). The Proteobacteria were the dominant group (49.8% of all OTUs), with the Acidobacteria also well represented (19.57% of all OTUs). Analysis of qPCR results identified spatial relationships between soil series, site location, and gene abundance, which could be used to infer both incomplete and total DEA rates.

Sensitivity of Active and Passive Microwave Observations to Soil Moisture during Growing Corn

NASA Astrophysics Data System (ADS)

Judge, J.; Monsivais-Huertero, A.; Liu, P.; De Roo, R. D.; England, A. W.; Nagarajan, K.

2011-12-01

Soil moisture (SM) in the root zone is a key factor governing water and energy fluxes at the land surface and its accurate knowledge is critical to predictions of weather and near-term climate, nutrient cycles, crop-yield, and ecosystem productivity. Microwave observations, such as those at L-band, are highly sensitive to soil moisture in the upper few centimeters (near-surface). The two satellite-based missions dedicated to soil moisture estimation include, the European Space Agency's Soil Moisture and Ocean Salinity (SMOS) mission and the planned NASA Soil Moisture Active/Passive (SMAP) [4] mission. The SMAP mission will include active and passive sensors at L-band to provide global observations of SM, with a repeat coverage of every 2-3 days. These observations can significantly improve root zone soil moisture estimates through data assimilation into land surface models (LSMs). Both the active (radar) and passive (radiometer) microwave sensors measure radiation quantities that are functions of soil dielectric constant and exhibit similar sensitivities to SM. In addition to the SM sensitivity, radar backscatter is highly sensitive to roughness of soil surface and scattering within the vegetation. These effects may produce a much larger dynamic range in backscatter than that produced due to SM changes alone. In this study, we discuss the field observations of active and passive signatures of growing corn at L-band from several seasons during the tenth Microwave, Water and Energy Balance Experiment (MicroWEX-10) conducted in North Central Florida, and to understand the sensitivity of these signatures to soil moisture under dynamic vegetation conditions. The MicroWEXs are a series of season-long field experiments conducted during the growing seasons of sweet corn, cotton, and energy cane over the past six years (for example, [22]). The corn was planted on July 5 and harvested on September 23, 2011 during MicroWEX-10. The size of the field was 0.04 km2 and the soils at the site were Lakeland fine sand, with 89% sand content by volume. The crop was heavily irrigated via a linear move irrigation system. Every 15-minute ground-based passive and active microwave observations at L-band were conducted at an incidence angle of 40°. In addition, concurrent observations were conducted of soil moisture, temperature, heat flux at various depths in the root zone, along with concurrent micrometeorological conditions. Weekly vegetation sampling included measurements of LAI, green and dry biomass of stems, leaves, and ears, crop height and width, vertical distribution of moisture in the canopy, leaf size and orientation, other phonological observations. Such observations at high temporal density allow detailed sensitivity analyses as the vegetation grows.

The organization of the actin cytoskeleton in vertical and graviresponding primary roots of maize

NASA Technical Reports Server (NTRS)

Blancaflor, E. B.; Hasenstein, K. H.

1997-01-01

To determine whether actin microfilament (MF) organization is correlated with differential elongation, primary roots of Zea mays cv Merit maintained vertically or reoriented horizontally for 15 to 120 min were stained with rhodamine phalloidin and examined with a confocal microscope. Root curvature was measured with a computer-controlled video digitizer. In vertical roots bundles of MFs in the elongation and maturation zone were oriented parallel to the longitudinal axis of cells. MFs in the vascular parenchyma cells were more abundant than in the cortex and epidermis. Epidermal and proendodermal cells in the meristematic region contained transverse cortical MFs. The organization of MFs of graviresponding roots was similar to that of vertical roots. Application of cytochalasin B or cytochalasin D resulted in extensive disruption of MFs in the cortex and epidermis, but only partially affected MFs in the stele. Despite the cytochalasin B-induced depolymerization of MFs, gravicurvature exceeded that of controls. In contrast, the auxin transport inhibitor N-1 naphthylphthalamic acid suppressed root curvature but had no observable effect on the integrity of the MFs. The data indicate that MFs may not be involved in the graviresponse of maize roots.

Protein association of β-N-methylamino-L-alanine in Triticum aestivum via irrigation.

PubMed

Contardo-Jara, Valeska; Schwanemann, Torsten; Esterhuizen-Londt, Maranda; Pflugmacher, Stephan

2018-04-01

Bioaccumulation of several cyanotoxins has been observed in numerous food webs. More recently, the neurotoxic, non-proteinogenic amino acid β-N-methylamino-L-alanine (BMAA) was shown to biomagnify in marine food webs. It was thus necessary to assess whether a human exposure risk via a terrestrial food source could exist. As shown for other cyanotoxins, spray irrigation of crop plants with cyanobacterial bloom-contaminated surface water poses the risk of toxin transfer into edible plant parts. Therefore, in the present study, we evaluated a possible transfer of BMAA via spray irrigation into the seeds of one of the world's most widely cultivated crop plants, Triticum aestivum. Wheat plants were irrigated with water containing 10 µg L -1 BMAA until they reached maturity and seed-bearing stage (205 days). Several morphological characteristics, such as germination rate, number of roots per seedling, length of primary root and cotyledon, and diameter of the stems were evaluated to assess the effects of chronic exposure. After 205 days, BMAA bioaccumulation was quantified in roots, shoots, and mature seeds of T. aestivum. No adverse morphology effects were observed and no free intracellular BMAA was detected in any of the exposed plants. However, in mature seeds, protein-associated BMAA was detected at 217 ± 150 ng g FW -1 ; significantly more than in roots and shoots. This result demonstrates the unexpected bioaccumulation of a hydrophilic compound and highlights the demand to specify in addition to limit values for drinking water, tolerable daily intake rates for the cyanobacterial-neurotoxin BMAA.

Visualization of removal of trapped air from the apical region of the straight root canal models generating 2-phase intermittent counter flow during ultrasonically activated irrigation.

PubMed

Peeters, Harry Huiz; Iskandar, Bernard; Suardita, Ketut; Suharto, Djoko

2014-06-01

The purpose of this in vitro study was to obtain a better understanding of the mechanism of irrigant traveling apically and generating 2-phase intermittent counter flow in straight root canal models during activation of the irrigant by ultrasonic means in an endodontic procedure. A high-speed imaging system, with high temporal and spatial resolution (FastCam SA5; Photron, Tokyo, Japan) at a frame rate of 100,000 frames per second using a macro lens (60 mm, f/2.8; Nikon, Tokyo, Japan), was used to visualize, in glass models of root canals, an ultrasonically induced acoustic pressure wave in an EDTA solution environment. A 25-mm stainless steel noncutting file #20 driven by an ultrasonic device (P5 Newtron; Satelec Acteon, Mérignac, France) at power settings of 5 and 7 produced disturbances at the solution-air interface. We found that apically directed travel of the irrigant was caused by disruption of the surface tension at the solution-air interface. This disruption caused by ultrasonic activation energy displaced air in the form of bubbles from the apical region toward the solution. The apical movement of the solution may be attributed to ultrasonically induced wave generation at the solution-air interface, resulting in the removal of trapped air from the root canal and allowing the solution to travel apically in the opposite directions (via a 2-phase intermittent counter flow). Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

A GIS-based assessment of groundwater suitability for irrigation purposes in flat areas of the wet Pampa plain, Argentina.

PubMed

Romanelli, Asunción; Lima, María Lourdes; Quiroz Londoño, Orlando Mauricio; Martínez, Daniel Emilio; Massone, Héctor Enrique

2012-09-01

The Pampa in Argentina is a large plain with a quite obvious dependence on agriculture, water availability and its quality. It is a sensitive environment due to weather changes and slope variations. Supplementary irrigation is a useful practice for compensating the production in the zone. However, potential negative impacts of this type of irrigation in salinization and sodification of soils are evident. Most conventional methodologies for assessing water irrigation quality have difficulties in their application in the region because they do not adjust to the defined assumptions for them. Consequently, a new GIS-based methodology integrating multiparametric data was proposed for evaluating and delineating groundwater suitability zones for irrigation purposes in flat areas. Hydrogeological surveys including water level measurements, groundwater samples for chemical analysis and electrical conductivity (EC) measurements were performed. The combination of EC, sodium adsorption ratio, residual sodium carbonate, slopes and hydraulic gradient parameters generated an irrigation water index (IWI). With the integration of the IWI 1 to 3 classes (categories of suitable waters for irrigation) and the aquifer thickness the restricted irrigation water index (RIWI) was obtained. The IWI's index application showed that 61.3 % of the area has "Very high" to "Moderate" potential for irrigation, while the 31.4 % of it has unsuitable waters. Approximately, 46 % of the tested area has high suitability for irrigation and moderate groundwater availability. This proposed methodology has advantages over traditional methods because it allows for better discrimination in homogeneous areas.

The evolution of root zone moisture storage capacities after deforestation: a step towards hydrological predictions under change?

NASA Astrophysics Data System (ADS)

Nijzink, Remko C.; Hutton, Christopher; Pechlivanidis, Ilias; Capell, René; Arheimer, Berit; Freer, Jim; Han, Dawei; Wagener, Thorsten; McGuire, Kevin; Savenije, Hubert; Hrachowitz, Markus

2017-04-01

The moisture storage available to vegetation is a key parameter in the hydrological functioning of ecosystems. This parameter, the root zone storage capacity, determines the partitioning between runoff and transpiration, but is impossible to observe at the catchment scale. In this research, data from the experimental forests of HJ Andrews (Oregon, USA) and Hubbard Brook (New Hampshire, USA) was used to test the hypotheses that: (1) the root zone storage capacity significantly changes after deforestation, (2) changes in the root zone storage capacity can to a large extent explain post-treatment changes to the hydrological regimes and that (3) a time-dynamic formulation of the root zone storage can improve the performance of a hydrological model. At first, root zone storage capacities were estimated based on a simple, water-balance based method. Briefly, the maximum difference between cumulative rainfall and estimated transpiration was determined, which could be considered a proxy for root zone storage capacity. These values were compared with root zone storage capacities obtained from four conceptual models (HYPE, HYMOD, FLEX, TUW), calibrated for consecutive 2-year windows. Both methods showed a sharp decline in root zone storage capacity after deforestation, which was followed by a gradual recovery signal. It was found in a trend analysis that these recovery periods took between 5 and 13 years for the different catchments. Eventually, one of the models was adjusted to allow for a time-dynamic formulation of root zone storage capacity. This adjusted model showed improvements in model performance as evaluated by 28 hydrological signatures, such as rising limb density or peak flows. Thus, this research clearly shows the time-dynamic character of a crucial parameter, which is often considered to remain constant in time. Root zone storage capacities are strongly affected by deforestation, leading to changes in hydrological regimes, and time-dynamic formulations of root zone storage are therefore necessary in systems under change.

SEBAL Model Using to Estimate Irrigation Water Efficiency & Water Requirement of Alfalfa Crop

NASA Astrophysics Data System (ADS)

Zeyliger, Anatoly; Ermolaeva, Olga

2013-04-01

The sustainability of irrigation is a complex and comprehensive undertaking, requiring an attention to much more than hydraulics, chemistry, and agronomy. A special combination of human, environmental, and economic factors exists in each irrigated region and must be recognized and evaluated. A way to evaluate the efficiency of irrigation water use for crop production is to consider the so-called crop-water production functions, which express the relation between the yield of a crop and the quantity of water applied to it or consumed by it. The term has been used in a somewhat ambiguous way. Some authors have defined the Crop-Water Production Functions between yield and the total amount of water applied, whereas others have defined it as a relation between yield and seasonal evapotranspiration (ET). In case of high efficiency of irrigation water use the volume of water applied is less than the potential evapotranspiration (PET), then - assuming no significant change of soil moisture storage from beginning of the growing season to its end-the volume of water may be roughly equal to ET. In other case of low efficiency of irrigation water use the volume of water applied exceeds PET, then the excess of volume of water applied over PET must go to either augmenting soil moisture storage (end-of-season moisture being greater than start-of-season soil moisture) or to runoff or/and deep percolation beyond the root zone. In presented contribution some results of a case study of estimation of biomass and leaf area index (LAI) for irrigated alfalfa by SEBAL algorithm will be discussed. The field study was conducted with aim to compare ground biomass of alfalfa at some irrigated fields (provided by agricultural farm) at Saratov and Volgograd Regions of Russia. The study was conducted during vegetation period of 2012 from April till September. All the operations from importing the data to calculation of the output data were carried by eLEAF company and uploaded in Fieldlook web geo database and used for experiment program managment. Quite good agreement between measured and calculated biomass and LAI were obtained. Estimation of effectiveness of water efficiency as well as estimation of applied water losses were done in the base of supplied irrigation water provided by local operating irrigation water supply companies and data of soil moisture monitoring. Following analyse of the remote sensing use to estimate of crop water requirement will be presented. ACKNOWLEDGMENTS. This study was financially supported by G2G project

[Effects of different techniques on removal of vapor lock in the apical region of curved canals: a cone-beam computed tomography study].

PubMed

Su, Z; Bai, Y H; Hou, X M

2017-02-18

To compare the effect of four different techniques on removal of vapor lock in the apical region of curved root canals. Forty simulated resin root canals with 45° curvature were prepared using WaveOne Primary, then the apical foramen were sealed with soft wax. The teeth were divided randomly into 4 groups thereafter (n=10). Contract solution was injected into the canals using a 30 G side-vented needle and scanned with cone-beam CT (CBCT) to identify the volume of the vapor lock. Four different techniques including photon-induced photoacoustic streaming (PIPS) laser-activated irrigation, gutta-percha cone technique, ultrasonic irrigation, and sonic irrigation were used to remove the vapor locks in the root canals. The residual volume of the vapor lock was identified again using CBCT scanning data. Accordingly, the reduction rates of the vapor lock were calculated. Furthermore, the initial and residual vapor lock length was calculated. The data were analyzed by using the One-way ANOVA analysis and Kruskal-Wallis H test at a significance level of P<0.05. There was no significant difference in the initial vapor lock volume (P>0.05). Residual volume of the vapor lock for PIPS laser-activated irrigation was 0 mm(3), and that for gutta-percha cone technique was (0.02±0.07) mm3, significantly lower than those of ultrasonic and sonic irrigation, the values being (0.20±0.09) mm(3) and (0.23±0.06) mm(3) (P<0.001), respectively. The reduction rates of the vapor lock of PIPS laser-activated irrigation and gutta-percha cone technique were 100.00% (100.00%, 100.00%) and 100.00% (77.66%, 100.00%), respectively, significantly higher than those of ultrasonic irrigation [70.37% (56.41%, 91.43%)] and sonic irrigation [63.54% (51.47%, 74.00%), P<0.001]. The length of the residual vapor lock for PIPS laser-activated irrigation was 0 mm, and that for gutta-percha cone technique was (0.15±0.47) mm, significantly lower than those of ultrasonic and sonic irrigation, values being (2.21±0.09) mm and (2.34±0.08) mm (P<0.001), respectively. The length of the residual vapor locks in the ultrasonic and sonic group remained approximately the same as the distance between the working tip and the apical foramen. PIPS laser activated irrigation and gutta-percha cone technique could remove the vapor lock from the apical region of curved canals effectively.

Antibacterial Efficacy of Super-Oxidized Water on Enterococcus faecalis Biofilms in Root Canal

PubMed Central

Zan, Recai; Alacam, Tayfun; Hubbezoglu, Ihsan; Tunc, Tutku; Sumer, Zeynep; Alici, Oguzhan

2016-01-01

Background The success of endodontic treatment depends on a few crucial factors. One of these factors is the complete chemomechanic preparation of root canal against various bacteria. In particular, the effect of resistant bacteria may cause intense pain with flare-up and formation of periapical lesions. Therefore, the strong effect of irrigants plays an important role in terms of the complete elimination of these bacteria to achieve long-term successful treatment. Objectives The aim of this study was to investigate the antibacterial effects of super-oxidized water (SPO) in root canals infected with Enterococcus faecalis biofilms. Methods One hundred twenty single-root, premolar teeth were selected. Initially, the teeth were prepared and then disinfected. E. faecalis were inoculated and kept at 37°C for 24 hours in the root canals. The re-inoculation procedure was repeated on the first, fourth, seventh, and tenth days. The infected root canals were divided into one negative (saline) and one positive (sodium hypochlorite) control group and four experimental groups (super-oxidized water: 1, 2, 3, or 5 minutes) (n = 20). Paper points were placed in the root canals to control and evaluate the biofilm formation. Biofilms were counted on blood agar plates, and data was evaluated and statistically analyzed using one-way ANOVA and Tukey’s test. Results Although sodium hypochlorite (NaOCl) showed no statistically significant difference when compared with three and five minutes of SPO irrigation (P > 0.05), NaOCl showed statistically significant differences among all other groups (P < 0.05). Conclusions Super-oxidized water indicated a remarkable and similar bactericidal effect to that of traditional NaOCl against E. faecalis biofilms. In terms of successful endodontic treatment approaches, super-oxidized water may be used as an effective irrigation solution in clinics. PMID:27800142

Effect of aquatine endodontic cleanser on smear layer removal in the root canals of ex vivo human teeth

PubMed Central

GARCIA, Faustino; MURRAY, Peter E.; GARCIA-GODOY, Franklin; NAMEROW, Kenneth N.

2010-01-01

Objectives The purpose of this study was to measure and compare the root canal cleanliness and smear layer removal effectiveness of Aquatine Endodontic Cleanser (Aquatine EC) when used as an endodontic irrigating solution in comparison with 6% sodium hypochlorite (NaOCl). Material and Methods Forty-five human teeth were randomly allocated to five treatment groups; the pulp chamber was accessed, cleaned, and shaped by using ProTaper and ProFile rotary instrumentation to an ISO size #40. The teeth were then processed for scanning electron microscopy, and the root canal cleanliness and removal of smear layer were examined. Results The most effective removal of smear layer occurred with Aquatine EC and NaOCl, both with a rinse of EDTA. Conclusions Aquatine EC appears to be the first hypochlorous acid approved by the FDA to be a possible alternative to the use of NaOCl as an intracanal irrigant. Further research is needed to identify safer and more effective alternatives to the use of NaOCl irrigation in endodontics. PMID:20835577

Evaluation of Apical Extrusion of Debris and Irrigant Using Two New Reciprocating and One Continuous Rotation Single File Systems

PubMed Central

Nayak, Gurudutt; Singh, Inderpreet; Shetty, Shashit; Dahiya, Surya

2014-01-01

Objective: Apical extrusion of debris and irrigants during cleaning and shaping of the root canal is one of the main causes of periapical inflammation and postoperative flare-ups. The purpose of this study was to quantitatively measure the amount of debris and irrigants extruded apically in single rooted canals using two reciprocating and one rotary single file nickel-titanium instrumentation systems. Materials and Methods: Sixty human mandibular premolars, randomly assigned to three groups (n = 20) were instrumented using two reciprocating (Reciproc and Wave One) and one rotary (One Shape) single-file nickel-titanium systems. Bidistilled water was used as irrigant with traditional needle irrigation delivery system. Eppendorf tubes were used as test apparatus for collection of debris and irrigant. The volume of extruded irrigant was collected and quantified via 0.1-mL increment measure supplied on the disposable plastic insulin syringe. The liquid inside the tubes was dried and the mean weight of debris was assessed using an electronic microbalance. The data were statistically analysed using Kruskal-Wallis nonparametric test and Mann Whitney U test with Bonferroni adjustment. P-values less than 0.05 were considered significant. Results: The Reciproc file system produced significantly more debris compared with OneShape file system (P<0.05), but no statistically significant difference was obtained between the two reciprocating instruments (P>0.05). Extrusion of irrigant was statistically insignificant irrespective of the instrument or instrumentation technique used (P >0.05). Conclusions: Although all systems caused apical extrusion of debris and irrigant, continuous rotary instrumentation was associated with less extrusion as compared with the use of reciprocating file systems. PMID:25628665

The effects of different irrigation protocols on removing calcium hydroxide from the root canals.

PubMed

Üstün, Y; Aslan, T; Sagsen, B; Dincer, A N

2016-01-01

The aim of this study was to evaluate the efficiencies of different irrigation protocols and solutions in the removal of calcium hydroxide (Ca[OH]2). Sixty-eight maxillary incisors were used. Root canals were prepared and filled with Ca(OH)2. Two control (n = 4) and six experimental groups (n = 10) were adjusted: Group 1:1% peracetic acid (PAA) + master apical file (MAF); Group 2: 17% ethylenediaminetetraacetic acid (EDTA) + MAF; Group 3: 9% 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) + MAF; Group 4: 1% PAA + ultrasonic activation (UA); Group 5: 17% EDTA + UA; Group 6: 9% HEBP + UA. The cleanliness of root canal thirds were evaluated with scanning electron microscopy. Statistical analysis were performed (α = 0.05). At coronal thirds; PAA + UA was superior to EDTA + MAF, HEBP + MAF; and PAA + MAF was superior to EDTA + MAF, HEBP + MAF (P < 0.05). At middle thirds; PAA + MAF and PAA + UA were superior to EDTA + MAF and EDTA + UA; and, PAA + UA was superior to HEBP + MAF (P < 0.05). There were no significant differences among the rest of the experimental groups (P > 0.05). Complete removal of Ca(OH)2could not be achieved by none of the irrigants at all root thirds.

Lysimeter Study of Plant Water Uptake in a Model Forest Ecosystem on Heavy Metal Contaminated Soil

NASA Astrophysics Data System (ADS)

Menon, M.; Abbaspour, K.; Schulin, R.; Oswald, S.

2003-04-01

We have been investigating the impact of heavy metal stress on the water regime of young forest ecosystems grown in 32 open top lysimeters (3 m in diameter and 1 m deep). The factorial treatments of the lysimeters include variations of rainwater acidity (acidic, ambient rain), subsoil type (acidic, calcareous), and soil contamination (with and without copper, zinc and cadmium in the top 20 cm). Each lysimeter was planted in spring of 2000 with the same selection of trees and herbaceous plants. All lysimeters are equipped with tensiometers for monitoring of pressure head and time domain reflectometry for measuring of water content. Irrigation was applied equally to all lysimeters through sprinkler devices. Drainage water was collected by means of canisters installed at the bottom of the lysimeters, and thus evapotranspiration could be calculated through water balancing. We monitored the water regime for two years including an imposed drought period. Significantly more water was extracted from the calcareous than the acidic subsoil. The water potential measurements show that also the heavy metal polluted topsoil had a significant influence on the water regime. Metal stress was particularly evident under reduced irrigation. We suspect that the roots were damaged in the contaminated topsoil. In contrast to the subsoil type, heavy metal pollution did not produce a significant effect on evapotranspiration (ET) though, and neither did acidic rain. Pot experiments confirmed that in presence of clean subsoil plants compensated for metal stress in contaminated topsoil by shifting their root activity from contaminated to uncontaminated zones.

Simulating Salt Movement and Transformation using a Coupled Reactive Transport Model in Variably-Saturated Groundwater Systems

NASA Astrophysics Data System (ADS)

Tavakoli Kivi, S.; Bailey, R. T.; Gates, T.

2016-12-01

Salinization is one of the major concerns in irrigated agricultural landscapes. Increasing salinity concentrations are due principally to evaporative concentration; dissolution of salts from weathered minerals and bedrock; and a high water table that results from excessive irrigation, canal seepage, and a lack of efficient drainage systems; leading to decreasing crop yield. High groundwater salinity loading to nearby river systems also impacts downstream areas, with saline river water diverted for application on irrigated fields. In this study, a solute transport model coupled with equilibrium chemistry reactions has been developed to simulate transport of individual salt ions in regional-scale aquifer systems and thereby investigate strategies for salinity remediation. The physically-based numerical model is based on the UZF-RT3D variably-saturated, multi-species groundwater reactive transport modeling code, and accounts for advection, dispersion, carbon and nitrogen cycling, oxidation-reduction reactions, and salt ion equilibrium chemistry reactions such as complexation, ion exchange, and precipitation/dissolution. Each major salt ion (sulfate, chloride, bicarbonate, calcium, sodium, magnesium, potassium) is included. The model has been tested against measured soil salinity at a small scale (soil profile) and against soil salinity, groundwater salinity, and groundwater salinity loading to surface water at the regional scale (500 km2) in the Lower Arkansas River Valley (LARV) in southeastern Colorado, an area acutely affected by salinization for many decades and greatly influenced by gypsum deposits. Preliminary results of using the model in scenario analysis suggest that increasing irrigation efficiency, sealing earthen canals, and rotational fallowing of land can decrease the groundwater salt load to the Arkansas River by 50 to 70% and substantially lower soil salinity in the root zone.

The influence of treeshelters and irrigation on shoot and root growth of three California oak species

Treesearch

Douglas McCreary; Laurence R. Costello; Jerry Tecklin; Katherine Jones; David Labadie

2002-01-01

Treeshelters are individual seedling protectors that can accelerate height growth of native California oaks. There is concern, however, that this growth may occur at the expense of the roots, resulting in poor long-term field performance. This study could detect no differences between protected and unprotected seedlings in shoot weight, root weight or shoot/root ratios...

Spatial and temporal patterns of root distribution in developing stands of four woody crop species grown with drip irrigation and fertilization

Treesearch

Mark Coleman

2007-01-01

In forest trees, roots mediate such significant carbon fluxes as primary production and soil C02 efflux. Despite the central role of roots in these critical processes, information on root distribution during stand establishment is limited, yet must be described to accurately predict how various forest types, which are growing with a range of...

Effect of Intermediate Flush Using Different Devices to Prevent Chemical Smear Layer Formation.

PubMed

Silva, Camilla Corrêa; Ferreira, Vivian Maria Durange; De-Deus, Gustavo; Herrera, Daniel Rodrigo; Prado, Maíra do; Silva, Emmanuel João Nogueira Leal da

2017-01-01

This study compared the effect of intermediate flush with distilled water delivered by conventional irrigation, EndoVac microcannula or Self-Adjusting File (SAF) system in the prevention of chemical smear layer (CSL) formation. Thirty human premolars were used. Canals were prepared with Reciproc system and 5.25% NaOCl. After chemomechanical preparation, samples were divided in 3 groups (n=10) according to the intermediate irrigation protocol with distilled water using: conventional irrigation, EndoVac microcannula or SAF. A final flush with 2% chlorhexidine solution was used and scanning electron microscopy was performed to assess protocol effectiveness. Two calibrated evaluators attributed scores according the presence or absence of CSL on the surface of the root canal walls at the coronal, middle and apical thirds, as follows: (1) no CSL; (2) small amounts of CSL; (3) moderate CSL; and (4) heavy CSL. Differences between protocols were analyzed with Kruskal-Wallis and Mann-Whitney U tests. Friedman and Wilcoxon signed rank tests were used for comparison between each root canal third. SAF resulted in less formation of CSL when compared with the conventional irrigation and EndoVac microcannula (p<0.05). When root canal thirds were analyzed, conventional irrigation and EndoVac groups showed less CSL formation at coronal and middle thirds in comparison to the apical third (p<0.05). In SAF group, there was no difference among the thirds (p>0.05). It may be concluded that an intermediate flush of distilled water, delivered by the SAF system resulted in a better reduction of CSL formation during chemomechanical preparation.

Field Performance of an Indica x Tropical Japonica Rice Mapping Population under AWD Stress

USDA-ARS?s Scientific Manuscript database

Alternating-wetting-drying (AWD) is an emerging rice irrigation management system that has the potential ability to reduce both irrigation water use and emissions of the greenhouse gas, methane. Based on preliminary experiments, 15 (F10) recombinant inbred lines (RILs) showing diversity for root an...

Effect of 95% Ethanol as a Final Irrigant before Root Canal Obturation in Primary Teeth: An in vitro Study.

PubMed

Thiruvenkadam, G; Asokan, Sharath; John, Baby; Priya, Pr Geetha

2016-01-01

Successful obturation in the primary teeth demands complete dryness of the root canal system. The purpose of this study was to determine the effect of 95% ethanol as the final irrigant before root canal obturation in primary teeth. A total of 20 extracted primary mandibular canines were biomechanically prepared and pre-obturated volume of each tooth was assessed using spiral computed tomography (CT). The specimens were divided into two groups (n = 10): group 1, Metapex group; group 2, zinc oxide eugenol group. Each group was further divided randomly into two subgroups (n = 5): subgroup 1, canals were dried with 95% ethanol; subgroup 2, canals were blot dried with paper points with the last one appearing dry. All canals were obturated and the postobturated volume of each tooth was measured. The percentage of obturated volume (POV) was calculated using the formula: (postobturated volume/preobturated volume) × 100. The POV between the groups was statistically analyzed using Mann-Whitney test and Wilcoxon Signed rank test appropriately. Root canals that were dried with ethanol showed better obturation than using paper points alone and the difference was statistically significant in both group 1 (p < 0.001) and group 2 (p < 0.002). Drying of the root canal system with 95% ethanol can result in better obturation in the primary teeth. How to cite this article: Thiruvenkadam G, Asokan S, John B, Geetha Priya PR. Effect of 95% Ethanol as a Final Irrigant before Root Canal Obturation in Primary Teeth: An in vitro Study. Int J Clin Pediatr Dent 2016;9(1):21-24.

Ensemble forecasting of short-term system scale irrigation demands using real-time flow data and numerical weather predictions

NASA Astrophysics Data System (ADS)

Perera, Kushan C.; Western, Andrew W.; Robertson, David E.; George, Biju; Nawarathna, Bandara

2016-06-01

Irrigation demands fluctuate in response to weather variations and a range of irrigation management decisions, which creates challenges for water supply system operators. This paper develops a method for real-time ensemble forecasting of irrigation demand and applies it to irrigation command areas of various sizes for lead times of 1 to 5 days. The ensemble forecasts are based on a deterministic time series model coupled with ensemble representations of the various inputs to that model. Forecast inputs include past flow, precipitation, and potential evapotranspiration. These inputs are variously derived from flow observations from a modernized irrigation delivery system; short-term weather forecasts derived from numerical weather prediction models and observed weather data available from automatic weather stations. The predictive performance for the ensemble spread of irrigation demand was quantified using rank histograms, the mean continuous rank probability score (CRPS), the mean CRPS reliability and the temporal mean of the ensemble root mean squared error (MRMSE). The mean forecast was evaluated using root mean squared error (RMSE), Nash-Sutcliffe model efficiency (NSE) and bias. The NSE values for evaluation periods ranged between 0.96 (1 day lead time, whole study area) and 0.42 (5 days lead time, smallest command area). Rank histograms and comparison of MRMSE, mean CRPS, mean CRPS reliability and RMSE indicated that the ensemble spread is generally a reliable representation of the forecast uncertainty for short lead times but underestimates the uncertainty for long lead times.