Lasting effects of soil health improvements with management changes in cotton-based cropping systems in a sandy soil

USDA-ARS?s Scientific Manuscript database

The soil microbial component is essential for sustainable agricultural systems and soil health. This study evaluated the lasting impacts of 5 years of soil health improvements from alternative cropping systems compared to intensively tilled continuous cotton (Cont. Ctn) in a low organic matter sandy...

Different Behavior of Enteric Bacteria and Viruses in Clay and Sandy Soils after Biofertilization with Swine Digestate

PubMed Central

Fongaro, Gislaine; García-González, María C.; Hernández, Marta; Kunz, Airton; Barardi, Célia R. M.; Rodríguez-Lázaro, David

2017-01-01

Enteric pathogens from biofertilizer can accumulate in the soil, subsequently contaminating water and crops. We evaluated the survival, percolation and leaching of model enteric pathogens in clay and sandy soils after biofertilization with swine digestate: PhiX-174, mengovirus (vMC0), Salmonella enterica Typhimurium and Escherichia coli O157:H7 were used as biomarkers. The survival of vMC0 and PhiX-174 in clay soil was significantly lower than in sandy soil (iT90 values of 10.520 ± 0.600 vs. 21.270 ± 1.100 and 12.040 ± 0.010 vs. 43.470 ± 1.300, respectively) and PhiX-174 showed faster percolation and leaching in sandy soil than clay soil (iT90 values of 0.46 and 2.43, respectively). S. enterica Typhimurium was percolated and inactivated more slowly than E. coli O157:H7 (iT90 values of 9.340 ± 0.200 vs. 6.620 ± 0.500 and 11.900 ± 0.900 vs. 10.750 ± 0.900 in clay and sandy soils, respectively), such that E. coli O157:H7 was transferred more quickly to the deeper layers of both soils evaluated (percolation). Our findings suggest that E. coli O157:H7 may serve as a useful microbial biomarker of depth contamination and leaching in clay and sandy soil and that bacteriophage could be used as an indicator of enteric pathogen persistence. Our study contributes to development of predictive models for enteric pathogen behavior in soils, and for potential water and food contamination associated with biofertilization, useful for risk management and mitigation in swine digestate recycling. PMID:28197137

Effects of sodium polyacrylate on water retention and infiltration capacity of a sandy soil.

PubMed

Zhuang, Wenhua; Li, Longguo; Liu, Chao

2013-01-01

Based on the laboratory study, the effects of sodium polyacrylate (SP) was investigated at 5 rates of 0, 0.08, 0.2, 0.5, and 1%, on water retention, saturated hydraulic conductivity(Ks), infiltration characteristic and water distribution profiles of a sandy soil. The results showed that water retention and available water capacity effectively increased with increasing SP rate. The Ks and the rate of wetting front advance and infiltration under certain pond infiltration was significantly reduced by increasing SP rate, which effectively reduced water in a sandy soil leaking to a deeper layer under the plough layer. The effect of SP on water distribution was obviously to the up layer and very little to the following deeper layers. Considering both the effects on water retention and infiltration capacity, it is suggested that SP be used to the sandy soil at concentrations ranging from 0.2 to 0.5%.

[Monitoring of water and salt transport in silt and sandy soil during the leaching process].

PubMed

Fu, Teng-Fei; Jia, Yong-Gang; Guo, Lei; Liu, Xiao-Lei

2012-11-01

Water and salt transport in soil and its mechanism is the key point of the saline soil research. The dynamic rule of water and transport in soil during the leaching process is the theoretical basis of formation, flush, drainage and improvement of saline soil. In this study, a vertical infiltration experiment was conducted to monitor the variation in the resistivity of silt and sandy soil during the leaching process by the self-designed automatic monitoring device. The experimental results showed that the peaks in the resistivity of the two soils went down and faded away in the course of leaching. It took about 30 minutes for sandy soil to reach the water-salt balance, whereas the silt took about 70 minutes. With the increasing leaching times, the desalination depth remained basically the same, being 35 cm for sandy soil and 10 cm for the silt from the top to bottom of soil column. Therefore, 3 and 7 leaching processes were required respectively for the complete desalination of the soil column. The temporal and spatial resolution of this monitoring device can be adjusted according to the practical demand. This device can not only achieve the remote, in situ and dynamic monitoring data of water and salt transport, but also provide an effective method in monitoring, assessment and early warning of salinization.

Changes in physical properties of sandy soil after long-term compost treatment

NASA Astrophysics Data System (ADS)

Aranyos, József Tibor; Tomócsik, Attila; Makádi, Marianna; Mészáros, József; Blaskó, Lajos

2016-07-01

Studying the long-term effect of composted sewage sludge application on chemical, physical and biological properties of soil, an experiment was established in 2003 at the Research Institute of Nyíregyháza in Hungary. The applied compost was prepared from sewage sludge (40%), straw (25%), bentonite (5%) and rhyolite (30%). The compost was ploughed into the 0-25 cm soil layer every 3rd year in the following amounts: 0, 9, 18 and 27 Mg ha-1 of dry matter. As expected, the compost application improved the structure of sandy soil, which is related with an increase in the organic matter content of soil. The infiltration into soil was improved significantly, reducing the water erosion under simulated high intensity rainfall. The soil compaction level was reduced in the first year after compost re-treatment. In accordance with the decrease in bulk density, the air permeability of soil increased tendentially. However, in the second year the positive effects of compost application were observed only in the plots treated with the highest compost dose because of quick degradation of the organic matter. According to the results, the sewage sludge compost seems to be an effective soil improving material for acidic sandy soils, but the beneficial effect of application lasts only for two years.

Assessment of physical and chemical indicators of sandy soil quality for sustainable crop production

NASA Astrophysics Data System (ADS)

Lipiec, Jerzy; Usowicz, Boguslaw

2017-04-01

Sandy soils are used in agriculture in many regions of the world. The share of sandy soils in Poland is about 55%. The aim of this study was to assess spatial variability of soil physical and chemical properties affecting soil quality and crop yields in the scale of field (40 x 600 m) during three years of different weather conditions. The experimental field was located on the post glacial and acidified sandy deposits of low productivity (Szaniawy, Podlasie Region, Poland). Physical soil quality indicators included: content of sand, silt, clay and water, bulk density and those chemical: organic carbon, cation exchange capacity, acidity (pH). Measurements of the most soil properties were done at spring and summer each year in topsoil and subsoil layer in 150 points. Crop yields were evaluated in places close to measuring points of the soil properties. Basic statistics including mean, standard deviation, skewness, kurtosis minimal, maximal and correlations between the soil properties and crop yields were calculated. Analysis of spatial dependence and distribution for each property was performed using geostatistical methods. Mathematical functions were fitted to the experimentally derived semivariograms that were used for mapping the soil properties and crop yield by kriging. The results showed that the largest variations had clay content (CV 67%) and the lowest: sand content (5%). The crop yield was most negatively correlated with sand content and most positively with soil water content and cation exchange capacity. In general the exponential semivariogram models fairly good matched to empirical data. The range of semivariogram models of the measured indicators varied from 14 m to 250 m indicate high and moderate spatial variability. The values of the nugget-to-sill+nugget ratios showed that most of the soil properties and crop yields exhibited strong and moderate spatial dependency. The kriging maps allowed identification of low yielding sub-field areas that

Expanded uncertainty estimation methodology in determining the sandy soils filtration coefficient

NASA Astrophysics Data System (ADS)

Rusanova, A. D.; Malaja, L. D.; Ivanov, R. N.; Gruzin, A. V.; Shalaj, V. V.

2018-04-01

The combined standard uncertainty estimation methodology in determining the sandy soils filtration coefficient has been developed. The laboratory researches were carried out which resulted in filtration coefficient determination and combined uncertainty estimation obtaining.

Study of sandy soil grain-size distribution on its deformation properties

NASA Astrophysics Data System (ADS)

Antropova, L. B.; Gruzin, A. V.; Gildebrandt, M. I.; Malaya, L. D.; Nikulina, V. B.

2018-04-01

As a rule, new oil and gas fields' development faces the challenges of providing construction objects with material and mineral resources, for example, medium sand soil for buildings and facilities footings of the technological infrastructure under construction. This problem solution seems to lie in a rational usage of the existing environmental resources, soils included. The study was made of a medium sand soil grain-size distribution impact on its deformation properties. Based on the performed investigations, a technique for controlling sandy soil deformation properties was developed.

Toluene removal from sandy soils via in situ technologies with an emphasis on factors influencing soil vapor extraction.

PubMed

Amin, Mohammad Mehdi; Hatamipour, Mohammad Sadegh; Momenbeik, Fariborz; Nourmoradi, Heshmatollah; Farhadkhani, Marzieh; Mohammadi-Moghadam, Fazel

2014-01-01

The integration of bioventing (BV) and soil vapor extraction (SVE) appears to be an effective combination method for soil decontamination. This paper serves two main purposes: it evaluates the effects of soil water content (SWC) and air flow rate on SVE and it investigates the transition regime between BV and SVE for toluene removal from sandy soils. 96 hours after air injection, more than 97% removal efficiency was achieved in all five experiments (carried out for SVE) including 5, 10, and 15% for SWC and 250 and 500 mL/min for air flow rate on SVE. The highest removal efficiency (>99.5%) of toluene was obtained by the combination of BV and SVE (AIBV: Air Injection Bioventing) after 96 h of air injection at a constant flow rate of 250 mL/min. It was found that AIBV has the highest efficiency for toluene removal from sandy soils and can remediate the vadose zone effectively to meet the soil guideline values for protection of groundwater.

Toluene Removal from Sandy Soils via In Situ Technologies with an Emphasis on Factors Influencing Soil Vapor Extraction

PubMed Central

Amin, Mohammad Mehdi; Hatamipour, Mohammad Sadegh; Nourmoradi, Heshmatollah; Farhadkhani, Marzieh; Mohammadi-Moghadam, Fazel

2014-01-01

The integration of bioventing (BV) and soil vapor extraction (SVE) appears to be an effective combination method for soil decontamination. This paper serves two main purposes: it evaluates the effects of soil water content (SWC) and air flow rate on SVE and it investigates the transition regime between BV and SVE for toluene removal from sandy soils. 96 hours after air injection, more than 97% removal efficiency was achieved in all five experiments (carried out for SVE) including 5, 10, and 15% for SWC and 250 and 500 mL/min for air flow rate on SVE. The highest removal efficiency (>99.5%) of toluene was obtained by the combination of BV and SVE (AIBV: Air Injection Bioventing) after 96 h of air injection at a constant flow rate of 250 mL/min. It was found that AIBV has the highest efficiency for toluene removal from sandy soils and can remediate the vadose zone effectively to meet the soil guideline values for protection of groundwater. PMID:24587723

Soil Physical Constraints on Intrinsic Biodegradation of Petroleum Vapors in a Layered Subsurface

PubMed Central

Kristensen, Andreas H.; Henriksen, Kaj; Mortensen, Lars; Scow, Kate M.; Moldrup, Per

2011-01-01

Naturally occurring biodegradation of petroleum hydrocarbons in the vadose zone depends on the physical soil environment influencing field-scale gas exchange and pore-scale microbial metabolism. In this study, we evaluated the effect of soil physical heterogeneity on biodegradation of petroleum vapors in a 16-m-deep, layered vadose zone. Soil slurry experiments (soil/water ratio 10:30 w/w, 25°C) on benzene biodegradation under aerobic and well-mixed conditions indicated that the biodegradation potential in different textured soil samples was related to soil type rather than depth, in the order: sandy loam > fine sand > limestone. Similarly, O2 consumption rates during in situ respiration tests performed at the site were higher in the sandy loam than in the fine sand, although the difference was less significant than in the slurries. Laboratory and field data generally agreed well and suggested a significant potential for aerobic biodegradation, even with nutrient-poor and deep subsurface conditions. In slurries of the sandy loam, the biodegradation potential declined with increasing in situ water saturation (i.e., decreasing air-filled porosity in the field). This showed a relation between antecedent undisturbed field conditions and the slurry biodegradation potential, and suggested airfilled porosity to be a key factor for the intrinsic biodegradation potential in the field. PMID:21617737

Screening identification of aerobic denitrification bacteria with high soil desalinization capacity

NASA Astrophysics Data System (ADS)

Jin, H.; Chen, H.; Jin, H.; Qian, Y.; Zhang, K.

2017-08-01

In order to study the mechanism of bacteria used in the saline soil remediation process, the aerobic denitrification bacteria were isolated from an agricultural greenhouse soil in a farm in East China’s Zhejiang Province. The identification, nitrogen reducing characteristics and the denitrification effect of bacteria from different soils at various locations were investigated. The results showed that the NO3- removal rate was 91% with bacteria from the greenhouse soil under aerobic conditions in 52 h, and the bacteria were identified as Gram-positive Castellaniella denitrification bacteria.

Assessment of grass root effects on soil piping in sandy soils using the pinhole test

NASA Astrophysics Data System (ADS)

Bernatek-Jakiel, Anita; Vannoppen, Wouter; Poesen, Jean

2017-04-01

Soil piping is a complex land degradation process, which involves the hydraulic removal of soil particles by subsurface flow. This process is frequently underestimated and omitted in most soil erosion studies. However, during the last decades several studies reported the importance of soil piping in various climatic zones and for a wide range of soil types. Compared to sheet, rill and gully erosion, very few studies focused on the factors controlling piping and, so far, there is no research study dealing with the effects of plant roots on piping susceptibility of soils having a low cohesion. The objective of this study is therefore to assess the impact of grass root density (RD) on soil piping in sandy soils using the pinhole test. The pinhole test involves a water flow passing through a hole of 1 mm diameter in a soil specimen (sampled using a metal ring with a diameter of 5 cm and a length of 8 cm), under varying hydraulic heads (50 mm, 180 mm, 380 mm and 1020 mm; Nadal-Romero et al., 2011). To provide a quantitative assessment piping susceptibility of the soil sample, the pipeflow discharge (cm3 s-1) and the sediment discharge (g s-1) were measured every minute during a five minute test. Bare and root-permeated samples were tested, using a sandy soil with a sand, silt, clay content of respectively, 94%, 4% and 2%. The root-permeated topsoil samples were taken in field plots sown with a mixture of grasses with fibrous roots. All soil samples were placed on a sandbox with a 100 mm head for 24 hours to ensure a similar water content for all samples. In total, 67 pinhole tests (lasting 5 minutes each) were conducted, i.e. 43 root-permeated soil samples with RD ranging from 0.01 to 0.93 kg m-3 and 24 root-free soil samples as a reference. Clear piping erosion could be observed in 65% of the root-free soil samples, whereas only 17% of rooted soil samples revealed clear piping erosion during the tests. Statistical analyses show that there is a negative correlation (-0

Remediation of sandy soils contaminated with hydrocarbons and halogenated hydrocarbons by soil vapour extraction.

PubMed

Albergaria, José Tomás; Alvim-Ferraz, Maria da Conceição M; Delerue-Matos, Cristina

2012-08-15

This paper presents the study of the remediation of sandy soils containing six of the most common contaminants (benzene, toluene, ethylbenzene, xylene, trichloroethylene and perchloroethylene) using soil vapour extraction (SVE). The influence of soil water content on the process efficiency was evaluated considering the soil type and the contaminant. For artificially contaminated soils with negligible clay contents and natural organic matter it was concluded that: (i) all the remediation processes presented efficiencies above 92%; (ii) an increase of the soil water content led to a more time-consuming remediation; (iii) longer remediation periods were observed for contaminants with lower vapour pressures and lower water solubilities due to mass transfer limitations. Based on these results an easy and relatively fast procedure was developed for the prediction of the remediation times of real soils; 83% of the remediation times were predicted with relative deviations below 14%. Copyright © 2012 Elsevier Ltd. All rights reserved.

Fit-for-purpose phosphorus management: do riparian buffers qualify in catchments with sandy soils?

PubMed

Weaver, David; Summers, Robert

2014-05-01

Hillslope runoff and leaching studies, catchment-scale water quality measurements and P retention and release characteristics of stream bank and catchment soils were used to better understand reasons behind the reported ineffectiveness of riparian buffers for phosphorus (P) management in catchments with sandy soils from south-west Western Australia (WA). Catchment-scale water quality measurements of 60 % particulate P (PP) suggest that riparian buffers should improve water quality; however, runoff and leaching studies show 20 times more water and 2 to 3 orders of magnitude more P are transported through leaching than runoff processes. The ratio of filterable reactive P (FRP) to total P (TP) in surface runoff from the plots was 60 %, and when combined with leachate, 96 to 99 % of P lost from hillslopes was FRP, in contrast with 40 % measured as FRP at the large catchment scale. Measurements of the P retention and release characteristics of catchment soils (<2 mm) compared with stream bank soil (<2 mm) and the <75-μm fraction of stream bank soils suggest that catchment soils contain more P, are more P saturated and are significantly more likely to deliver FRP and TP in excess of water quality targets than stream bank soils. Stream bank soils are much more likely to retain P than contribute P to streams, and the in-stream mixing of FRP from the landscape with particulates from stream banks or stream beds is a potential mechanism to explain the change in P form from hillslopes (96 to 99 % FRP) to large catchments (40 % FRP). When considered in the context of previous work reporting that riparian buffers were ineffective for P management in this environment, these studies reinforce the notion that (1) riparian buffers are unlikely to provide fit-for-purpose P management in catchments with sandy soils, (2) most P delivered to streams in sandy soil catchments is FRP and travels via subsurface and leaching pathways and (3) large catchment-scale water quality measurements

Aerobic methanol-oxidizing bacteria in soil.

PubMed

Kolb, Steffen

2009-11-01

Methanol is an atmospheric compound that is primarily released from plant polymers and impacts ozone formation. The global methanol emission rate from terrestrial ecosystems is of the same order of magnitude (4.9 x 10(12) mol year(-1)) as that of methane (10 x 10(12) mol year(-1)). The major proportion of the annual plant-released methanol does not enter the atmosphere, but may be reoxidized by biological methanol oxidation, which is catalyzed by methanol-oxidizing prokaryotes. Fifty-six aerobic methanol-oxidizing species have been isolated from soils. These methylotrophs belong to the Alpha-, Beta-, and Gammaproteobacteria, Verrucomicrobia, Firmicutes, and Actinobacteria. Their ecological niches are determined by oxygen and methanol concentration, temperature, pH, the capability to utilize nitrate as an electron acceptor, and the spectrum of nitrogen sources and utilizable multicarbon substrates. Recently discovered interactions with eukaryotes indicate that their ecological niches may not solely be defined by physicochemical parameters. Nonetheless, there are still gaps in knowledge; based on global methanol budgets, methanol oxidation in soil is important, but has not been addressed adequately by biogeochemical studies. Ratios of above-ground and soil-internal methanol oxidation are not known. The contribution to methanol-oxidation by aerobic and anaerobic methylotrophs in situ also needs further research.

Irrigation initiation timing in soybean grown on sandy soils in Northeast Arkansas

USDA-ARS?s Scientific Manuscript database

Irrigation initiation timing was evaluated in furrow-irrigated soybean field with sandy soils in Mississippi County, AR. A major objective of this 2015 study was to validate and expand irrigation timing recommendations that pair plant growth measures with weather cues including use of local weather ...

[Soil moisture dynamics of artificial Caragana microphylla shrubs at different topographical sites in Horqin sandy land].

PubMed

Huang, Gang; Zhao, Xue-yong; Huang, Ying-xin; Su, Yan-gui

2009-03-01

Based on the investigation data of vegetation and soil moisture regime of Caragana microphylla shrubs widely distributed in Horqin sandy land, the spatiotemporal variations of soil moisture regime and soil water storage of artificial sand-fixing C. microphylla shrubs at different topographical sites in the sandy land were studied, and the evapotranspiration was measured by water balance method. The results showed that the soil moisture content of the shrubs was the highest in the lowland of dunes, followed by in the middle, and in the crest of the dunes, and increased with increasing depth. No water stress occurred during the growth season of the shrubs. Soil moisture content of the shrubs was highly related to precipitation event, and the relationship of soil moisture content with precipitation was higher in deep soil layer (50-180 cm) than in shallow soil layer (0-50 cm). The variation coefficient of soil moisture content was also higher in deep layer than in shallow layer. Soil water storage was increasing in the whole growth season of the shrubs, which meant that the accumulation of soil water occurred in this area. The evapotranspiriation of the shrubs occupied above 64% of the precipitation.

SOIL AND HYDROLOGY OF A WET-SANDY CATENA IN EAST-CENTRAL MINNESOTA

EPA Science Inventory

Sail properties are strongly related to the retention and movement of water within the soil system. The purposes of this study were to document the near-surface hydrology of a wetland-upland hillslope on a sandy glacial outwash plain in east-central Minnesota and to describe the ...

Assessment of grass root effects on soil piping in sandy soils using the pinhole test

NASA Astrophysics Data System (ADS)

Bernatek-Jakiel, Anita; Vannoppen, Wouter; Poesen, Jean

2017-10-01

Soil piping is an important land degradation process that occurs in a wide range of environments. Despite an increasing number of studies on this type of subsurface erosion, the impact of vegetation on piping erosion is still unclear. It can be hypothesized that vegetation, and in particular plant roots, may reduce piping susceptibility of soils because roots of vegetation also control concentrated flow erosion rates or shallow mass movements. Therefore, this paper aims to assess the impact of grass roots on piping erosion susceptibility of a sandy soil. The pinhole test was used as it provides quantitative data on pipeflow discharge, sediment concentration and sediment discharge. Tests were conducted at different hydraulic heads (i.e., 50 mm, 180 mm, 380 mm and 1020 mm). Results showed that the hydraulic head was positively correlated with pipeflow discharge, sediment concentration and sediment discharge, while the presence of grass roots (expressed as root density) was negatively correlated with these pipeflow characteristics. Smaller sediment concentrations and sediment discharges were observed in root-permeated samples compared to root-free samples. When root density exceeds 0.5 kg m- 3, piping erosion rates decreased by 50% compared to root-free soil samples. Moreover, if grass roots are present, the positive correlation between hydraulic head and both sediment discharge and sediment concentration is less pronounced, demonstrating that grass roots become more effective in reducing piping erosion rates at larger hydraulic heads. Overall, this study demonstrates that grass roots are quite efficient in reducing piping erosion rates in sandy soils, even at high hydraulic head (> 1 m). As such, grass roots may therefore be used to efficiently control piping erosion rates in topsoils.

Garlic mustard and its effects on soil microbial communities in a sandy pine forest in central Illinois

Treesearch

Alexander B. Faulkner; Brittany E. Pham; Truc-Quynh D. Nguyen; Kenneth E. Kitchell; Daniel S. O' Keefe; Kelly D. McConnaughay; Sherri J. Morris

2014-01-01

This study evaluated the impacts of garlic mustard (Alliaria petiolata), an invasive species, on soil microbial community dynamics in a pine plantation on sandy soils in central Illinois. In situ soil carbon dioxide efflux was significantly greater in invaded sites. Similarly, in vitro carbon mineralization was significantly greater for soils...

[Soil sandy desertification and salinization and their interrelationships in Yanghuang irrigated area of Hongsipu, Ningxia of northwest China].

PubMed

Yang, Xin-guo; Song, Nai-ping

2011-09-01

By the methods of controlled and typical sampling, this paper analyzed the texture, salinization characteristics, cation exchange capacity (CEC), and their correlations in the 0-40 cm soil profiles of corn land, medlar land, and non-utilized land in Yanghuang irrigated area of Hongsipu, Northwest China. Under controlled sampling, the salt content in the soil profiles was 0.69-1.30 g x kg(-1) (except in non-utilized land where the 0-10 cm soil salt content was up to 1.74 g x kg(-1)), with no obvious salinization. The sodium adsorption ratio and exchangeable sodium percentage in the 20-40 cm soil layer of medlar land were 12.18 and 14.1%, respectively, and the total content of clay and silt in the 0-40 cm soil profile of medlar land was up to 37.3% whereas that in the 0-20 cm soil layer of corn land was only 13.5%. In the 20-40 cm soil layer of corn land, the indices of sandy desertification and salinization had significant correlations under controlled sampling but no correlations under typical sampling, while the CEC and the sandy desertification and salinization indices had significant correlations under typical sampling. In different land use types in the study area, soil sandy desertification and salinization had complicated interrelationships, and CEC could be used as the indicator for the changes in soil environmental quality.

Occurrence, fate, and persistence of gemfibrozil in water and soil.

PubMed

Fang, Yu; Karnjanapiboonwong, Adcharee; Chase, Darcy A; Wang, Jiafan; Morse, Audra N; Anderson, Todd A

2012-03-01

Pharmaceuticals and personal care products (PPCPs) have emerged as a group of potential environmental contaminants of concern. The occurrence of gemfibrozil, a lipid-regulating drug, was studied in the influent and effluent at a wastewater treatment plant (WWTP) and groundwater below a land application site receiving treated effluent from the WWTP. In addition, the sorption of gemfibrozil in two loam soils and sand was assessed, and biological degradation rates in two soil types under aerobic conditions were also determined. Results showed that concentrations of gemfibrozil in wastewater influent, effluent, and groundwater were in the range of 3.47 to 63.8 µg/L, 0.08 to 19.4 µg/L, and undetectable to 6.86 µg/L, respectively. Data also indicated that gemfibrozil in the wastewater could reach groundwater following land application of the treated effluent. Soil-water distribution coefficients for gemfibrozil, determined by the batch equilibrium method, varied with organic carbon content in the soils. The sorption capacity was silt loam > sandy loam > sand. Under aerobic conditions, dissipation half-lives for gemfibrozil in sandy loam and silt loam soils were 17.8 and 20.6 days, respectively; 25.4 and 11.3% of gemfibrozil was lost through biodegradation from the two soils over 14 days. Copyright © 2011 SETAC.

AEROBIC SOIL MICROCOSMS FOR LONG-TERM BIODEGRADATION OF HYDROCARBON VAPORS

EPA Science Inventory

The aims of this research project included the development of laboratory protocols for the preparation of aerobic soil microcosms using aseptic field soil samples, and for the gas chromatographic analysis of hydrocarbon vapor biodegradation based on vapor samples obtained from th...

Estimating water retention curves for sandy soils at the Doñana National Park, SW Spain

USDA-ARS?s Scientific Manuscript database

The determination of soil water retention curves (SWRC) in the laboratory is a slow and tedious task, which is especially challenging for sandy soils due to their low water retention capacity and large water content changes for small pressure head differences. Due to spatial variability within larg...

Production of PFOS from aerobic soil biotransformation of two perfluoroalkyl sulfonamide derivatives.

PubMed

Mejia Avendaño, Sandra; Liu, Jinxia

2015-01-01

The continuous production and use in certain parts of the world of perfluoroalkyl sulfonamide derivatives that can degrade to perfluorooctane sulfonic acid (PFOS) has called for better understanding of the environmental fate of these PFOS precursors. Aerobic soil biotransformation of N-ethyl perfluorooctane sulfonamide (EtFOSA, also known as Sulfluramid) was quantitatively investigated in semi-closed soil microcosms over 182 d for the first time. The apparent soil half-life of EtFOSA was 13.9±2.1 d and the yield to PFOS by the end of incubation was 4.0 mol%. A positive identification of a previously suspected degradation product, EtFOSA alcohol, provided strong evidence to determine degradation pathways. The lower mass balance in sterile soil than live soil suggested likely strong irreversible sorption of EtFOSA to the test soil. The aerobic soil biotransformation of a technical grade N-ethyl perfluorooctane sulfonamidoethanol (EtFOSE) was semi-quantitatively examined, and the degradation pathways largely followed those in activated sludge and marine sediments. Aside from PFOS, major degradation products included N-Ethyl perfluorooctane sulfonamidoacetic acid (EtFOSAA), perfluorooctane sulfonamide (FOSA) and perfluorooctane sulfonamide acetic acid (FOSAA). This study confirms that aerobic soil biotransformation of EtFOSE and EtFOSA contributes significantly to the PFOS observed in soil environment, as well as to several highly persistent sulfonamide derivatives frequently detected in biosolid-amended soils and landfill leachates. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biological soil crust formation under artificial vegetation effect and its properties in the Mugetan sandy land, northeastern Qinghai-Tibet Plateau

NASA Astrophysics Data System (ADS)

Li, Y. F.; Li, Z. W.; Jia, Y. H.; Zhang, K.

2016-08-01

Mugetan sandy land is an inland desertification area of about 2,065 km2 in the northeastern Qinghai-Tibet Plateau. In the ecological restoration region of the Mugetan sandy land, different crusts have formed under the action of vegetation in three types of sandy soil (i.e. semi-fixed sand dune, fixed sand dune and ancient fixed aeolian sandy soil). The surface sand particle distribution, mineral component and vegetation composition of moving sand dunes and three types of sandy soil were studied in 2010-2014 to analyze the biological crust formation properties in the Mugetan sandy land and the effects of artificial vegetation. Results from this study revealed that artificial vegetation increases the clay content and encourages the development of biological curst. The fine particles (i.e. clay and humus) of the surface layer of the sand dunes increased more than 15% ten years after the artificial vegetation planting, and further increased up to 20% after one hundred years. The interaction of clay, humus, and other fine particles formed the soil aggregate structure. Meanwhile, under the vegetation effect from the microbes, algae, and moss, the sand particles stuck together and a biological crust formed. The interconnection of the partial crusts caused the sand dunes to gradually be fixed as a whole. Maintaining the integrity of the biological crust plays a vital role in fixing the sand under the crust. The precipitation and temperature conditions in the Mugetan sandy land could satisfy the demand of biological crust formation and development. If rational vegetation measures are adopted in the region with moving sand dunes, the lichen-moss-algae biological curst will form after ten years, but it still takes more time for the sand dunes to reach the nutrient enrichment state. If the biological curst is partly broken due to human activities, reasonable closure and restoration measures can shorten the restoration time of the biological crust.

Biochar reduces copper toxicity in Chenopodium quinoa Willd. In a sandy soil.

PubMed

Buss, Wolfram; Kammann, Claudia; Koyro, Hans-Werner

2012-01-01

Mining, smelting, land applications of sewage sludge, the use of fungicides containing copper (Cu), and other human activities have led to widespread soil enrichment and contamination with Cu and potentially toxic conditions. Biochar (BC) can adsorb several substances, ranging from herbicides to plant-inhibiting allelochemicals. However, the range of potential beneficial effects on early-stage plant growth with regard to heavy metal toxicity is largely unexplored. We investigated the ameliorating properties of a forestry-residue BC under Cu toxicity conditions on early plant growth. Young quinoa plants () were grown in the greenhouse in the presence of 0, 2, and 4% BC application (w/w) added to a sandy soil with 0, 50, or 200 μg g Cu supplied. The plants without BC showed severe stress symptoms and reduced growth shortly after Cu application of 50 μg g and died at 200 μg Cu g. Increasing BC concentrations in the growth medium significantly increased the plant performance without Cu toxicity or under Cu stress. At the 4% BC application rate, the plants with 200 μg g Cu almost reached the same biomass as in the control treatment. In the presence of BC, less Cu entered the plant tissues, which had reduced Cu concentrations in the order roots, shoots, leaves. The amelioration effect also was reflected in the plant-soil system CO gas exchange, which showed clear signs of improvement with BC presence. The most likely ameliorating mechanisms were adsorption of Cu to negatively charged BC surfaces and an improvement of the water supply. Overall, BC seems to be a beneficial amendment with the potential to ameliorate Cu toxicity in sandy soils. Further research with a broad spectrum of different soil types, BCs, and crop plants is required. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Intra-aggregate CO2 enrichment: a modelling approach for aerobic soils

NASA Astrophysics Data System (ADS)

Schlotter, D.; Schack-Kirchner, H.

2013-02-01

CO2 concentration gradients inside soil aggregates, caused by the respiration of soil microorganisms and fungal hyphae, might lead to variations in the soil solution chemistry on a mm-scale, and to an underestimation of the CO2 storage. But, up to now, there seems to be no feasible method for measuring CO2 inside natural aggregates with sufficient spatial resolution. We combined a one-dimensional model for gas diffusion in the inter-aggregate pore space with a cylinder diffusion model, simulating the consumption/production and diffusion of O2 and CO2 inside soil aggregates with air- and water-filled pores. Our model predicts that for aerobic respiration (respiratory quotient = 1) the intra-aggregate increase in the CO2 partial pressure can never be higher than 0.9 kPa for siliceous, and 0.1 kPa for calcaric aggregates, independent of the level of water-saturation. This suggests that only for siliceous aggregates CO2 produced by aerobic respiration might cause a high small-scale spatial variability in the soil solution chemistry. In calcaric aggregates, however, the contribution of carbonate species to the CO2 transport should lead to secondary carbonates on the aggregate surfaces. As regards the total CO2 storage in aerobic soils, both siliceous and calcaric, the effect of intra-aggregate CO2 gradients seems to be negligible. To assess the effect of anaerobic respiration on the intra-aggregate CO2 gradients, the development of a device for measuring CO2 on a mm-scale in soils is indispensable.

Light Gray Surface-Gleyed Loamy Sandy Soils of the Northern Part of Tambov Plain: Agroecology, Properties, and Diagnostics

NASA Astrophysics Data System (ADS)

Zaidel'man, F. R.; Stepantsova, L. V.; Nikiforova, A. S.; Krasin, V. N.; Dautokov, I. M.; Krasina, T. V.

2018-04-01

Light gray soils of Tambov oblast mainly develop from sandy and loamy sandy parent materials; these are the least studied soils in this region. Despite their coarse texture, these soils are subjected to surface waterlogging. They are stronger affected by the agrogenic degradation in comparison with chernozems and dark gray soils. Morphology, major elements of water regime, physical properties, and productivity of loamy sandy light gray soils with different degrees of gleyzation have been studied in the northern part of Tambov Plain in order to substantiate the appropriate methods of their management. The texture of these soils changes at the depth of 70-100 cm. The upper part is enriched in silt particles (16-30%); in the lower part, the sand content reaches 80-85%. In the nongleyed variants, middle-profile horizons contain thin iron-cemented lamellae (pseudofibers); in surface-gleyed variants, iron nodules are present in the humus horizon. The removal of clay from the humus horizon and its accumulation at the lithological contact and in pseudofibers promote surface subsidence and formation of microlows in the years with moderate and intense winter precipitation. The low range of active moisture favors desiccation of the upper horizons to the wilting point in dry years. The yield of cereal crops reaches 3.5-4.5 t/ha in the years with high and moderate summer precipitation on nongleyed and slightly gleyed light gray soils and decreases by 20-50% on strongly gleyed light gray soils. On light gray soils without irrigation, crop yields are unstable, and productivity of pastures is low. High yields of cereals and vegetables can be obtained on irrigated soils. In this case, local drainage measures should be applied to microlows; liming can be recommended to improve soil productivity.

Aerobic and anaerobic biosynthesis of nano-selenium for remediation of mercury contaminated soil.

PubMed

Wang, Xiaonan; Zhang, Daoyong; Pan, Xiangliang; Lee, Duu-Jong; Al-Misned, Fahad A; Mortuza, M Golam; Gadd, Geoffrey Michael

2017-03-01

Selenium (Se) nanoparticles are often synthesized by anaerobes. However, anaerobic bacteria cannot be directly applied for bioremediation of contaminated top soil which is generally aerobic. In this study, a selenite-reducing bacterium, Citrobacter freundii Y9, demonstrated high selenite reducing power and produced elemental nano-selenium nanoparticles (nano-Se 0 ) under both aerobic and anaerobic conditions. The biogenic nano-Se 0 converted 45.8-57.1% and 39.1-48.6% of elemental mercury (Hg 0 ) in the contaminated soil to insoluble mercuric selenide (HgSe) under anaerobic and aerobic conditions, respectively. Addition of sodium dodecyl sulfonate enhanced Hg 0 remediation, probably owing to the release of intracellular nano-Se 0 from the bacterial cells for Hg fixation. The reaction product after remediation was identified as non-reactive HgSe that was formed by amalgamation of nano-Se 0 and Hg 0 . Biosynthesis of nano-Se 0 both aerobically and anaerobically therefore provides a versatile and cost-effective remediation approach for Hg 0 -contaminated surface and subsurface soils, where the redox potential often changes dramatically. Copyright © 2016. Published by Elsevier Ltd.

Aerobic biotransformation of polyfluoroalkyl phosphate esters (PAPs) in soil.

PubMed

Liu, Chen; Liu, Jinxia

2016-05-01

Microbial transformation of polyfluoroalkyl phosphate esters (PAPs) into perfluorocarboxylic acids (PFCAs) has recently been confirmed to occur in activated sludge and soil. However, there lacks quantitative information about the half-lives of the PAPs and their significance as the precursors to PFCAs. In the present study, the biotransformation of 6:2 and 8:2 diPAP in aerobic soil was investigated in semi-dynamics reactors using improved sample preparation methods. To develop an efficient extraction method for PAPs, six different extraction solvents were compared, and the phenomenon of solvent-enhanced hydrolysis was investigated. It was found that adding acetic acid could enhance the recoveries of the diPAPs and inhibit undesirable hydrolysis during solvent extraction of soil. However 6:2 and 8:2 monoPAPs, which are the first breakdown products from diPAPs, were found to be unstable in the six solvents tested and quickly hydrolyzed to form fluorotelomer alcohols. Therefore reliable measurement of the monoPAPs from a live soil was not achievable. The apparent DT50 values of 6:2 diPAP and 8:2 diPAP biotransformation were estimated to be 12 and > 1000 days, respectively, using a double first-order in parallel model. At the end of incubation of day 112, the major degradation products of 6:2 diPAP were 5:3 fluorotelomer carboxylic acid (5:3 acid, 9.3% by mole), perfluoropentanoic acid (PFPeA, 6.4%) and perfluorohexanoic acid (PFHxA, 6.0%). The primary product of 8:2 diPAP was perfluorooctanoic acid (PFOA, 2.1%). The approximately linear relationship between the half-lives of eleven polyfluoroalkyl and perfluoroalkyl substances (PFASs, including 6:2 and 8:2 diPAPs) that biotransform in aerobic soils and their molecular weights suggested that the molecular weight is a good indicator of the general stability of low-molecular-weight PFAS-based compounds in aerobic soils. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of leachate on geotechnical characteristics of sandy clay soil

NASA Astrophysics Data System (ADS)

Harun, N. S.; Ali, Z. Rahman; Rahim, A. S.; Lihan, T.; Idris, R. M. W.

2013-11-01

Leachate is a hazardous liquid that poses negative impacts if leaks out into environments such as soil and ground water systems. The impact of leachate on the downgraded quality in terms of chemical characteristic is more concern rather than the physical or mechanical aspect. The effect of leachate on mechanical behaviour of contaminated soil is not well established and should be investigated. This paper presents the preliminary results of the effects of leachate on the Atterberg limit, compaction and shear strength of leachate-contaminated soil. The contaminated soil samples were prepared by mixing the leachate at ratiosbetween 0% and 20% leachate contents with soil samples. Base soil used was residual soil originated from granitic rock and classified as sandy clay soil (CS). Its specific gravity ranged between 2.5 and 2.64 with clay minerals of kaolinite, muscovite and quartz. The field strength of the studied soil ranged between 156 and 207 kN/m2. The effects of leachate on the Atterberg limit clearly indicated by the decrease in liquid and plastic limit values with the increase in the leachate content. Compaction tests on leachate-contaminated soil caused the dropped in maximum dry density, ρdry and increased in optimum moisture content, wopt when the amount of leachate was increased between 0% and 20%. The results suggested that leachate contamination capable to modify some geotechnical properties of the studied residual soils.

Alum amendment effects on phosphorus release and distribution in poultry litter-amended sandy soils

USGS Publications Warehouse

Staats, K.E.; Arai, Y.; Sparks, D.L.

2004-01-01

Increased poultry production has contributed to excess nutrient problems in Atlantic Coastal Plain soils due to land application of poultry litter (PL). Aluminum sulfate [alum, Al2(SO4)3?? 14H2O] amendment of PL effectively reduces soluble phosphorus (P) in the PL; however, the effects of these litters when added to acidic, sandy soils are not well understood. The objective of this study was to investigate the efficacy of alum-amended poultry litter in reducing P release from three Delaware Coastal Plain soils: Evesboro loamy sand (Ev; excessively drained, mesic, coated Typic Quartzipsamments), Rumford loamy sand (Ru; well drained, coarse-loamy, siliceous, subactive, thermic Typic Hapludults), and Pocomoke sandy loam (Pm; very poorly drained, coarse-loamy, siliceous, active, thermic Typic Umbraquults). Long-term (25 d) and short-term (24 h) desorption studies were conducted, in addition to chemical extractions and kinetic modeling, to observe the changes that alum-amended versus unamended PL caused in the soils. The Ev, Ru, and Pm soils were incubated with 9 Mg ha-1 of alum-amended or unamended PL. Long-term desorption (25 d) of the incubated material resulted in approximately 13.5% (Ev), 12.7% (Ru), and 13.3% (Pm) reductions in cumulative P desorbed when comparing soil treated with unamended and alum-amended PL. In addition, the P release from the soil treated with alum-amended litter was not significantly different from the control (soil alone). Short-term desorption (24 h) showed 7.3% (Ev), 15.4% (Ru), and 20% (Pm) reductions. The overall implication from this study is that the use of alum as a PL amendment is useful in coarse-textured soils of the Coastal Plain. With increased application of alum-amended PL, more significant decreases may be possible with little or no effect on soil quality.

Characterization of biomass residues and their amendment effects on water sorption and nutrient leaching in sandy soil.

PubMed

Wang, Letian; Tong, Zhaohui; Liu, Guodong; Li, Yuncong

2014-07-01

In this study, we evaluated the efficiency of two types of biomass residues (fermentation residues from a bioethanol process, FB; brown mill residues from a papermaking process, BM) as amendments for a sandy soil. The characteristics of these residues including specific surface areas, morphologies and nutrient sorption capacity were measured. The effects of biorefinery residues on water and nutrient retention were investigated in terms of different particle sizes and loadings. The results indicated that bio-based wastes FB and BM were able to significantly improve water and nutrient retention of sandy soil. The residues with larger surface areas had better water and nutrient retention capability. Specifically, in the addition of 10% loading, FB and BM was able to improve water retention by approximately 150% and 300%, while reduce 99% of ammonium and phosphate concentration in the leachate compare to the soil control, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Effects of long-term fertilization on pH buffer system of sandy loam calcareous fluvor-aquic soil].

PubMed

Wang, Ji-Dong; Qi, Bing-Jie; Zhang, Yong-Chun; Zhang, Ai-Jun; Ning, Yun-Wang; Xu, Xian-Ju; Zhang, Hui; Ma, Hong-Bo

2012-04-01

Soil samples (0-80 cm) were collected from a 30-year fertilization experimental site in Xuzhou, Jiangsu Province of East China to study the variations of the pH, calcium carbonate and active calcium carbonate contents, and pH buffer capacity of sandy loam calcareous fluvor-aquic soil under different fertilization treatments. Thirty-year continuous application of different fertilizers accelerated the acidification of topsoil (0-20 cm), with the soil pH decreased by 0.41-0.70. Under different fertilization, the soil pH buffer capacity (pHBC) varied from 15.82 to 21.96 cmol x kg(-1). As compared with no fertilization, single N fertilization decreased the pHBC significantly, but N fertilization combined with organic fertilization could significantly increase the pHBC. The soil pHBC had significant positive correlations with soil calcium carbonate and active calcium carbonate contents, but less correlation with soil organic matter content and soil cation exchange capacity, suggesting that after a long-term fertilization, the sandy loam calcareous fluvor-aquic soil was still of an elementary calcium carbonate buffer system, and soil organic matter and cation exchange capacity contributed little to the buffer system. The soil calcium carbonate and active calcium carbonate contents were greater in 0-40 cm than in 40-80 cm soil layer. Comparing with soil calcium carbonate, soil active calcium carbonate was more sensitive to reflect the changes of soil physical and chemical properties, suggesting that the calcium carbonate buffer system could be further classified as soil active calcium carbonate buffer system.

Nitroglycerin degradation mediated by soil organic carbon under aerobic conditions.

PubMed

Bordeleau, Geneviève; Martel, Richard; Bamba, Abraham N'Valoua; Blais, Jean-François; Ampleman, Guy; Thiboutot, Sonia

2014-10-01

The presence of nitroglycerin (NG) has been reported in shallow soils and pore water of several military training ranges. In this context, NG concentrations can be reduced through various natural attenuation processes, but these have not been thoroughly documented. This study aimed at investigating the role of soil organic matter (SOM) in the natural attenuation of NG, under aerobic conditions typical of shallow soils. The role of SOM in NG degradation has already been documented under anoxic conditions, and was attributed to SOM-mediated electron transfer involving different reducing agents. However, unsaturated soils are usually well-oxygenated, and it was not clear whether SOM could participate in NG degradation under these conditions. Our results from batch- and column-type experiments clearly demonstrate that in presence of dissolved organic matter (DOM) leached from a natural soil, partial NG degradation can be achieved. In presence of particulate organic matter (POM) from the same soil, complete NG degradation was achieved. Furthermore, POM caused rapid sorption of NG, which should result in NG retention in the organic matter-rich shallow horizons of the soil profile, thus promoting degradation. Based on degradation products, the reaction pathway appears to be reductive, in spite of the aerobic conditions. The relatively rapid reaction rates suggest that this process could significantly participate in the natural attenuation of NG, both on military training ranges and in contaminated soil at production facilities. Copyright © 2014 Elsevier B.V. All rights reserved.

[Soil moisture dynamics and water balance of Salix psammophila shrubs in south edge of Mu Us Sandy Land].

PubMed

An, Hui; An, Yu

2011-09-01

Taking the artificial sand-fixing Salix psammophila shrubs with different plant density (0.2, 0.6, and 0.8 plants x m(-2)) in Mu Us Sandy Land as test objects, this paper studied the soil moisture dynamics and evapotranspiration during growth season. There existed obvious differences in the soil moisture dynamics and evapotranspiration among the shrubs. The soil moisture content changed in single-hump-shape with the increase of plant density, and in "S" shape during growth season, being closely correlated with precipitation. The evapotranspiration was the highest (114.5 mm) in the shrubs with a density 0.8 plants x m(-1), accounting for 90.8% of the total precipitation during growth season, and the lowest (109.7 mm) in the shrubs with a density 0.6 plants x m(-2) Based on the soil moisture dynamics and water balance characteristics, the appropriate planting density of S. psammophila shrubs in Mu Us Sandy Land could be 0.6 plants x m(-2).

Microbial and physical properties as indicators of sandy soil quality under cropland and grassland

NASA Astrophysics Data System (ADS)

Frac, Magdalena; Lipiec, Jerzy; Usowicz, Boguslaw; Oszust, Karolina; Brzezinska, Malgorzata

2017-04-01

Land use is one of the key factor driving changes in soil properties influencing on soil health and quality. Microbial diversity and physical properties are sensitive indicators for assessing soil health and quality. The alterations of microbial diversity and physical properties following land use changes have not been sufficiently elucidated, especially for sandy soils. We investigated microbial diversity indicators including fungal communities composition and physical properties of sandy acid soil under cropland and more than 20-yr-old grassland (after cropland) in Trzebieszów, Podlasie Region, Poland (N 51° 59' 24", E 22° 33' 37"). The study included four depths within 0-60 cm. Microbial genetic diversity was assessed by terminal restriction fragment length polymorphism (t-RFLP) analysis, fungal community composition was evaluated by next generation sequencing (NGS) analysis and functional diversity was determined by Biolog EcoPlate method. Overall microbial activity was assessed by soil enzymes (dehydrogenases, β-glucosidase) and respiration test. At the same places soil texture, organic carbon content, pH, bulk density, water holding capacity were determined. Our results showed that grassland soil was characterized by higher activity of soil enzymes than cropland. The average well color development of soil microorganisms, the microbial functional diversity and the number of carbon source utilization were significantly affected by land use type and were differentiated among soil depths. In grassland compared to cropland soil a significant increase of carboxylic acids and decrease of amino acids utilization was observed. The quantitative and qualitative differences were found in community of ammonia oxidizing archaea in cropland and grassland soil. The results of fungal community composition help to explain the soil health of grassland and cropland based on the appearance of phytopathogenic and antagonistic fungi. In general bulk density and field water

Retention and transport of mecoprop on acid sandy-loam soils

NASA Astrophysics Data System (ADS)

Paradelo Núñez, Remigio; Conde Cid, Manuel; Abad, Elodie Martin; Fernández Calviño, David; Nóvoa Muñoz, Juan Carlos; Arias Estévez, Manuel

2017-04-01

Interaction with soil components is one of the key processes governing the fate of agrochemicals in the environment. In this work, we have studied the adsorption/desorption and transport of mecoprop in four acid sandy-loam soils with different organic matter contents. Kinetics of adsorption and adsorption/desorption at equilibrium have been studied in batch experiments, whereas transport was studied in laboratory columns. Adsorption and desorption are linear or nearly-linear. The kinetics of mecoprop adsorption are relatively fast in all cases (less than 24 h). Adsorption and desorption were adequately described by the linear and Freundlich models, with KF values that ranged from 0.7 to 8.8 Ln µmol1-n kg-1 and KD values from 0.3 to 3.6 L kg-1. High desorption percentages (>50%) were found, indicative of a high reversibility of the adsorption process. The results of the transport experiments showed that the retention of mecoprop by soil was very low (less than 6.2%). The retention of mecoprop by the soils in all experiments increased with organic matter content. Overall, it was observed that mecoprop was weakly adsorbed by the soils, what would result in a high risk of leaching of this compound.

Effects of of habitats and pesticides on aerobic capacity and survival of soil fauna.

PubMed

Tripathi, G; Sharma, B M

2005-06-01

Faunal health is largely dependent on their soil environment and available litter quality. So the effects of different soil habitats and pesticides on citrate synthase (CS) activity of soil fauna and its population were studied. The soil animals were collected from different pedoecosystems for habitat study. Whereas Vigna radiata based system was selected for pesticidal observations. The field was divided into five equal plots for control and treatment of gamma-BHC, quinalphos, carbaryl and cypermethrin. Soil fauna was collected by quadrat method and extracted by Tullgren funnel. Individuals of a species having similar sizes were collected for the estimation of CS activity. They were homogenized and fractions were obtained by differential centrifugation. The activity of CS was assayed spectrophotometrically. Citrate synthase (CS) activity of beetle (Rasphytus fregi), woodlouse (Porcellio laevis) and centipede (Scolopendra morsitans) varied significantly with respect to changes in different soil habitats. Though the CS activity of R. fregi, P. laevis, and S. morsitans differed among themselves but the highest activity of CS in these animals was in V. radiata and lowest in A. nilotica based pedoecosystem. The aerobic capacity of centipede was maximum followed by woodlouse and beetle. The treatment of gamma-BHC, quinalphos, carbaryl and cypermethrin significantly reduced the CS activity of these animals. Gamma-BHC showed maximum reduction in CS activity indicating highly toxic effect of organochlorine on aerobic metabolism of soil fauna. However, minimum reduction was observed in response to carbaryl (in beetle) or cypermethrin (in woodlouse/centipede) leading to impairment of aerobic capacity. The differences in pesticide effects might be assigned to the differences in chemical nature of pesticides and their interactions with below-ground fauna. Treatment of gamma-BHC and quinalphos reduced the population of Acari, Coleoptera, Collembola, other arthropods as well as

[Effects of Different Residue Part Inputs of Corn Straws on CO2 Efflux and Microbial Biomass in Clay Loam and Sandy Loam Black Soils].

PubMed

Liu, Si-yi; Liang, Ai-zhen; Yang, Xue-ming; Zhang, Xiao-ping; Jia, Shu-xia; Chen, Xue-wen; Zhang, Shi-xiu; Sun, Bing-jie; Chen, Sheng-long

2015-07-01

The decomposed rate of crop residues is a major determinant for carbon balance and nutrient cycling in agroecosystem. In this study, a constant temperature incubation study was conducted to evaluate CO2 emission and microbial biomass based on four different parts of corn straw (roots, lower stem, upper stem and leaves) and two soils with different textures (sandy loam and clay loam) from the black soil region. The relationships between soil CO2 emission, microbial biomass and the ratio of carbon (C) to nitrogen (N) and lignin of corn residues were analyzed by the linear regression. Results showed that the production of CO2 was increased with the addition of different parts of corn straw to soil, with the value of priming effect (PE) ranged from 215. 53 µmol . g-1 to 335. 17 µmol . g -1. Except for corn leaves, the cumulative CO2 production and PE of clay loam soil were significantly higher than those in sandy loam soil. The correlation of PE with lignin/N was obviously more significant than that with lignin concentration, nitrogen concentration and C/N of corn residue. The addition of corn straw to soil increased the contents of MBC and MBN and decreased MBC/MBN, which suggested that more nitrogen rather than carbon was conserved in microbial community. The augmenter of microbial biomass in sandy loam soil was greater than that in clay loam soil, but the total dissolved nitrogen was lower. Our results indicated that the differences in CO2 emission with the addition of residues to soils were primarily ascribe to the different lignin/N ratio in different corn parts; and the corn residues added into the sandy loam soil could enhance carbon sequestration, microbial biomass and nitrogen holding ability relative to clay loam soil.

Toxicity of Nitro-Heterocyclic and Nitroaromatic Energetic Materials to Folsomia candida in a Natural Sandy Loam Soil

DTIC Science & Technology

2015-04-01

held in place with a rubber band. The mass of each container was then recorded to monitor soil - moisture loss during the test. Five replicates were used...relative humidity of 88 ± 5%. During the course of the study, the containers were weighed and misted weekly to maintain soil moisture levels. To...FOLSOMIA CANDIDA IN A NATURAL SANDY LOAM SOIL ECBC-TR-1272 Carlton T. Phillips Ronald T. Checkai Roman G. Kuperman Michael Simini Jan E

Microbial Degradation of Phenanthrene in Pristine and Contaminated Sandy Soils.

PubMed

Schwarz, Alexandra; Adetutu, Eric M; Juhasz, Albert L; Aburto-Medina, Arturo; Ball, Andrew S; Shahsavari, Esmaeil

2018-05-01

Phenanthrene mineralisation studies in both pristine and contaminated sandy soils were undertaken through detailed assessment of the activity and diversity of the microbial community. Stable isotope probing (SIP) was used to assess and identify active 13 C-labelled phenanthrene degraders. Baseline profiling indicated that there was little difference in fungal diversity but a significant difference in bacterial diversity dependent on contamination history. Identification of dominant fungal and bacterial species highlighted the presence of organisms capable of degrading various petroleum-based compounds together with other anthropogenic compounds, regardless of contamination history. Community response following a simulated contamination event ( 14 C-phenanthrene) showed that the microbial community in deep pristine and shallow contaminated soils adapted most to the presence of phenanthrene. The similarity in microbial community structure of well-adapted soils demonstrated that a highly adaptable fungal community in these soils enabled a rapid response to the introduction of a contaminant. Ten fungal and 15 bacterial species were identified as active degraders of phenanthrene. The fungal degraders were dominated by the phylum Basidiomycota including the genus Crypotococcus, Cladosporium and Tremellales. Bacterial degraders included the genera Alcanivorax, Marinobacter and Enterococcus. There was little synergy between dominant baseline microbes, predicted degraders and those that were determined to be actually degrading the contaminant. Overall, assessment of baseline microbial community in contaminated soils provides useful information; however, additional laboratory assessment of the microbial community's ability to degrade pollutants allows for better prediction of the bioremediation potential of a soil.

Aggregate-associated carbon and nitrogen in reclaimed sandy loam soils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wick, A.F.; Stahl, P.D.; Ingram, L.J.

2009-11-15

Minimal research has been conducted on aggregate, C, and N in coarse-textured soils used to reclaim surface coal mine lands. Furthermore, little is known about the contribution different plant communities make to the recovery of aggregation in these soils. Two chronosequences of semiarid reclaimed sites with sandy loam soils were sampled under shrub- and grass-dominated communities. Aggregation, aggregate fractions, and associated C and N were measured. No definitive trends of increasing macroaggregates between sites were observed undershrubs; however, macro- and microaggregation was greater in the 16-yr-old (0.20 and 0.23 kg aggregate kg{sup -1} soil, respectively) than in the 5-yr-old soilsmore » (0.02 and 0.08 kg aggregate kg{sup -1} soil, respectively) under grasses. Although C and N concentrations were drastically reduced (50-75%) with mining activity between the <1-yr-old and native soils, aggregate C and N concentrations tinder shrubs and grasses were similar to each other and to the native soils in the 5-yr-old site. Sods under grass in the 16-yr-old site had lower available and aggregate-occluded C and N concentrations than the 5-yr-old site, while C and N concentrations did not change between 5- and 16-yr-old soils under shrubs. Conversely, aggregate C and N pool sizes under shrubs and grasses both increased with site age to conditions similar to those observed in the native soil. Reclaimed shrub site soils had consistently higher C concentrations in the older reclaimed sites (10 and 16 yr old) than the soils under grasses, indicating greater accumulation and retention of C and N in organic material under shrub than grass communities in semiarid reclaimed sites.« less

Effect of treated wastewater application on soil water repellency of sandy soil with olive trees and grass cover

NASA Astrophysics Data System (ADS)

Diamantis, V.; Ziogas, A.; Giougis, J.; Pliakas, F.; Diamantis, I.

2009-04-01

Soil water repellency has received significant attention due to water scarcity and increasing demand of irrigation water worldwide. The objective of this study was to examine the effects of treated wastewater application on soil water repellency of a repellent sandy soil with olive trees and grass cover. Secondary effluent from a municipal wastewater treatment plant was applied directly on the field on a 4×2 m plot. Freshwater and a mixture of freshwater:wastewater (1:1) were used in subsequent plots for comparison. A total of 62 water applications were performed between March 2006 and July 2008. The soil receiving the mixture of freshwater:wastewater exhibited the highest wettability. The soil water repellency after the first year of wastewater application decreased in the respective plot compared with the soil under natural conditions. The higher values of the WDPT were determined on the freshwater irrigated plot. The field-moist samples on all plots revealed high wettability because the moisture content of the soil was maintained above the critical soil water content. The results of this study reveal that short-term application of treated municipal wastewater does not induce soil water repellency.

Degradation and persistence of cotton pesticides in sandy loam soils from Punjab, Pakistan.

PubMed

Tariq, Muhammad Ilyas; Afzal, Shahzad; Hussain, Ishtiaq

2006-02-01

The present study evaluated the influence of temperature, moisture, and microbial activity on the degradation and persistence of commonly used cotton pesticides, i.e., carbosulfan, carbofuran, lambda-cyhalothrin, endosulfan, and monocrotophos, with the help of laboratory incubation and lysimeter studies on sandy loam soil (Typic Ustocurepts) in Pakistan. Drainage from the lysimeters was sampled on days 49, 52, 59, 73, 100, 113, and 119 against the pesticide application on days 37, 63, 82, 108, and 137 after the sowing of cotton. Carbofuran, monocrotophos, and nitrate were detected in the drainage samples, with an average value, respectively, of 2.34, 2.6 microg/L, and 15.6 mg/L for no-tillage and 2.16, 2.3 microg/L, and 13.4 mg/L for tillage. In the laboratory, pesticide disappearance kinetics were measured with sterile and nonsterile soils from 0 to 10 cm in depth at 15, 25, and 35 degrees C and 50% and 90% field water capacities. Monocrotophos and carbosulfan dissipation followed first-order kinetics while others followed second-order kinetics. The results of incubation studies showed that temperature and moisture contents significantly reduced the t(1/2) (half-life) values of pesticides in sterile and nonsterile soil, but the effect of microbial activity was nearly significant that might be due to less organic carbon (0.3%). The presence of carbofuran and monocrotophos in the soil profile (0-10, 10-30, 30-60, 60-90, 90-150 cm) and the higher concentrations of endosulfan and lambda-cyhalothrin in the top layer (0-10 cm) showed the persistence of the pesticides. The detection of endosulfan and lambda-cyhalothrin in the 10-30 cm soil layer might be due to preferential flow. The data generated from this study could be helpful for risk assessment studies of pesticides and for validating pesticide transport models for sandy loam soils in cotton-growing areas of Pakistan.

Estimation of Nitrogen Pools in Irrigated Potato Production on Sandy Soil Using the Model SUBSTOR

PubMed Central

Prasad, Rishi; Hochmuth, George J.; Boote, Kenneth J.

2015-01-01

Recent increases in nitrate concentrations in the Suwannee River and associated springs in northern Florida have raised concerns over the contributions of non-point sources. The Middle Suwannee River Basin (MSRB) is of special concern because of prevalent karst topography, unconfined aquifers and sandy soils which increase vulnerability of the ground water contamination from agricultural operations- a billion dollar industry in this region. Potato (Solanum tuberosum L.) production poses a challenge in the area due to the shallow root system of potato plants, and low water and nutrient holding capacity of the sandy soils. A four-year monitoring study for potato production on sandy soil was conducted on a commercial farm located in the MSRB to identify major nitrogen (N) loss pathways and determine their contribution to the total environmental N load, using a partial N budget approach and the potato model SUBSTOR. Model simulated environmental N loading rates were found to lie within one standard deviation of the observed values and identified leaching loss of N as the major sink representing 25 to 38% (or 85 to 138 kg ha-1 N) of the total input N (310 to 349 kg ha-1 N). The crop residues left in the field after tuber harvest represented a significant amount of N (64 to 110 kg ha-1N) and posed potential for indirect leaching loss of N upon their mineralization and the absence of subsequent cover crops. Typically, two months of fallow period exits between harvest of tubers and planting of the fall row crop (silage corn). The fallow period is characterized by summer rains which pose a threat to N released from rapidly mineralizing potato vines. Strategies to reduce N loading into the groundwater from potato production must focus on development and adoption of best management practices aimed on reducing direct as well as indirect N leaching losses. PMID:25635904

Travel of pollution, and purification en route, in sandy soils

PubMed Central

Baars, J. K.

1957-01-01

The travel of pollution in sandy soils, and the extent to which purification takes place en route, are discussed, with special reference to the possible contamination of ground water—a problem which is of particular importance in the Netherlands, where the water-supply for many of the large towns is drawn from the water underneath the dunes. Specifically, two types of soil pollution are considered: (a) severe pollution of the surface layers with matter concentrated in a small volume of water (e.g., faecal matter from pit privies at camping-sites); and (b) moderate pollution of the surface layers with matter contained in large quantities of water (e.g., organic matter and bacteria in river water used for the artificial recharge of ground water). It is shown that in both these types of pollution the self-purification is sufficient to prevent contamination of the ground water, provided that the soil is very fine and—in the case of the first type—dry and well aerated, and provided that the ground-water level is not too high or the rate of infiltration too great. PMID:13472428

Diffusion and emissions of 1,3-dichloro propene in Florida sandy soil in microplots affected by soil moisture, organic matter, and plastic film.

PubMed

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

2004-04-01

The main objective of this study was to determine the influence of soil moisture, organic matter amendment and plastic cover (a virtually impermeable film, VIF) on diffusion and emissions of (Z)- and (E)-1,3-dichloropropene (1,3-D) in microplots of Florida sandy soil (Arredondo fine sand). Upward diffusion of the two isomers in the Arredondo soil without a plastic cover was greatly influenced by soil-water content and (Z)-1,3-D diffused faster than (E)-1,3-D. In less than 5 h after 1,3-D injection to 30 cm depth, (Z)- and (E)-1,3-D in air dry soil had diffused to a 10 cm depth, whereas diffusion for the two isomers was negligible in near-water-saturated soil, even 101 h after injection. The diffusion rate of (Z)- and (E)-1,3-D in near-field-capacity soil was between the rates in the two water regimes. Yard waste compost (YWC) amendment greatly reduced diffusion of (Z)- and (E)-1,3-D, even in air-dry soil. Although upward diffusion of (Z)- and (E)-1,3-D in soil with VIF cover was slightly less than in the corresponding bare soil; the cover promoted retention of vapors of the two isomers in soil pore air in the shallow subsurface. More (Z)-1,3-D vapor was found initially in soil pore air than (E)-1,3-D although the difference declined thereafter. As a result of rapid upward movement in air-dry bare soil, (Z)- and (E)-1,3-D were rapidly volatilized into the atmosphere, but emissions from the near-water-saturated soil were minimal. Virtually impermeable film and YWC amendment retarded emissions. This study indicated that adequate soil water in this sandy soil is needed to prevent rapid emissions, but excess soil water slows diffusion of (Z)- and (E)-1,3-D. Thus, management for optimum water in soil is critical for pesticidal efficacy and the environment.

Degradation pathway and field-scale DT50 determination of Boscalid in a sandy Soil

NASA Astrophysics Data System (ADS)

Karlsson, Anneli S.; Weihermüller, Lutz; Tappe, Wolfgang; Mukherjee, Santanu; Spielvogel, Sandra

2016-04-01

The research on environmental fate of pesticides has received increasing attention within the last decades and the persistence of several compounds in soil matrices is well documented. However, the fate of the new fungicide Boscalid (introduced in 2003) is not yet completely investigated. The aim of this study was to analyze the environmental fate of Boscalid in a sandy soil. Three years after the second application on a cropland site in Kaldenkirchen, Germany, 65 undisturbed soil samples from the plough layer were derived. Boscalid residues were extracted using Accelerated Solvent Extraction (ASE) and measured with UPLC-MS/MS. The Boscalid residues ranged between 0.12 and 0.53 μg kg-1with a field mean of 0.20 ± 0.09 μg kg-1. These results differed considerably from the predicted field concentration of 16.89 μg kg-1 (calculated from the application rate) and half-lives (DT50) of 104-182 days compared to 345 days reported in literature. Adjusting the extraction efficiency to 20% could not explain the large difference. Therefore, an incubation study with 14C-labeled Boscalid was conducted to measure the DT50 under controlled conditions. Here, the DT50 values were in the range of values stated in literature (297-337 days compared to 345 days) but still much larger than the DT50 based on the field-study values (104-182 days). Our results indicate that Boscalid dissipation under field conditions is much faster at agricultural sites with sandy soil type as expected from laboratory incubation experiments. Future experiments with Boscalid will be conducted in two different soils with different particle size. A laboratory experiment with uniformly 13C-labeled Boscalid will provide insight into the uptake and incorporation in microbial biomass.

An obligately aerobic soil bacterium activates fermentative hydrogen production to survive reductive stress during hypoxia.

PubMed

Berney, Michael; Greening, Chris; Conrad, Ralf; Jacobs, William R; Cook, Gregory M

2014-08-05

Oxygen availability is a major factor and evolutionary force determining the metabolic strategy of bacteria colonizing an environmental niche. In the soil, conditions can switch rapidly between oxia and anoxia, forcing soil bacteria to remodel their energy metabolism accordingly. Mycobacterium is a dominant genus in the soil, and all its species are obligate aerobes. Here we show that an obligate aerobe, the soil actinomycete Mycobacterium smegmatis, adopts an anaerobe-type strategy by activating fermentative hydrogen production to adapt to hypoxia. This process is controlled by the two-component system DosR-DosS/DosT, an oxygen and redox sensor that is well conserved in mycobacteria. We show that DosR tightly regulates the two [NiFe]-hydrogenases: Hyd3 (MSMEG_3931-3928) and Hyd2 (MSMEG_2719-2718). Using genetic manipulation and high-sensitivity GC, we demonstrate that Hyd3 facilitates the evolution of H2 when oxygen is depleted. Combined activity of Hyd2 and Hyd3 was necessary to maintain an optimal NAD(+)/NADH ratio and enhanced adaptation to and survival of hypoxia. We demonstrate that fermentatively-produced hydrogen can be recycled when fumarate or oxygen become available, suggesting Mycobacterium smegmatis can switch between fermentation, anaerobic respiration, and aerobic respiration. Hydrogen metabolism enables this obligate aerobe to rapidly meet its energetic needs when switching between microoxic and anoxic conditions and provides a competitive advantage in low oxygen environments.

Hydrological Components of a Young Loblolly Pine Plantation on a Sandy Soil with Estimates of Water Use and Loss

Treesearch

Deborah A. Abrahamson; Phillip M. Dougherty; Stanley J. Zarnoch

1998-01-01

Fertilizer and irrigation treatments were applied in a 7- to l0-year-old loblolly pine (Pinus taeda L.) plantation on a sandy soil near Laurinburg, North Carolina. Rainfall, throughfall, stemflow, and soil water content were measured throughout the study period. Monthly interception losses ranged from 4 to 15% of rainfall. Stemflow ranged from 0.2...

Self-purification of agrosoddy-podzolic sandy loamy soils fertilized with sewage sludge

NASA Astrophysics Data System (ADS)

Plekhanova, I. O.

2017-04-01

Sandy loamy agrosoddy-podzolic soils and plants growing on them were studied. The soils had been treated with sewage sludge from the Lyubertsy aeration station applied as organic fertilizer for 5-10 years before 1990. Initially, these soils were used for cultivating vegetables and fodder crops. The content and mobility of heavy metal compounds increased in the plow horizons of studied soils under the influence of sewage sludge. The concentrations of Cd and Zn exceeded the tentative permissible concentrations (TPC) for these elements by 8-16 and 2-4 times, respectively. The contaminated layer was found at the depths within 30-50 cm, which attests to a low migration rate of heavy metals added to the studied soils with sewage sludge (SS) 25 years ago. The concentration of Cd exceeded the maximum permissible concentration (MPC) of this element in all vegetable and fodder crops cultivated on the studied soils. The content of heavy metals in plants differed by three-five times in dependence on the capacity of particular plants to accumulate them. The period of soil self-purification from heavy metals was found to depend on the soil contamination level and element mobility, as well as on the element removal with harvested crops and with soil water flows. The maximal time of achieving the normal level of Cd concentration was estimated as 288 years for maximally contaminated soils; the corresponding values for Cu and Zn were estimated as 74 and 64 years, respectively.

Toxicity of iron oxide nanoparticles to grass litter decomposition in a sandy soil

NASA Astrophysics Data System (ADS)

Rashid, Muhammad Imtiaz; Shahzad, Tanvir; Shahid, Muhammad; Imran, Muhammad; Dhavamani, Jeyakumar; Ismail, Iqbal M. I.; Basahi, Jalal M.; Almeelbi, Talal

2017-02-01

We examined time-dependent effect of iron oxide nanoparticles (IONPs) at a rate of 2000 mg kg-1 soil on Cynodon dactylon litter (3 g kg-1) decomposition in an arid sandy soil. Overall, heterotrophic cultivable bacterial and fungal colonies, and microbial biomass carbon were significantly decreased in litter-amended soil by the application of nanoparticles after 90 and 180 days of incubation. Time dependent effect of nanoparticles was significant for microbial biomass in litter-amended soil where nanoparticles decreased this variable from 27% after 90 days to 49% after 180 days. IONPs decreased CO2 emission by 28 and 30% from litter-amended soil after 90 and 180 days, respectively. These observations indicated that time-dependent effect was not significant on grass-litter carbon mineralization efficiency. Alternatively, nanoparticles application significantly reduced mineral nitrogen content in litter-amended soil in both time intervals. Therefore, nitrogen mineralization efficiency was decreased to 60% after 180 days compared to that after 90 days in nanoparticles grass-litter amended soil. These effects can be explained by the presence of labile Fe in microbial biomass after 180 days in nanoparticles amendment. Hence, our results suggest that toxicity of IONPs to soil functioning should consider before recommending their use in agro-ecosystems.

An obligately aerobic soil bacterium activates fermentative hydrogen production to survive reductive stress during hypoxia

PubMed Central

Berney, Michael; Greening, Chris; Conrad, Ralf; Jacobs, William R.; Cook, Gregory M.

2014-01-01

Oxygen availability is a major factor and evolutionary force determining the metabolic strategy of bacteria colonizing an environmental niche. In the soil, conditions can switch rapidly between oxia and anoxia, forcing soil bacteria to remodel their energy metabolism accordingly. Mycobacterium is a dominant genus in the soil, and all its species are obligate aerobes. Here we show that an obligate aerobe, the soil actinomycete Mycobacterium smegmatis, adopts an anaerobe-type strategy by activating fermentative hydrogen production to adapt to hypoxia. This process is controlled by the two-component system DosR-DosS/DosT, an oxygen and redox sensor that is well conserved in mycobacteria. We show that DosR tightly regulates the two [NiFe]-hydrogenases: Hyd3 (MSMEG_3931-3928) and Hyd2 (MSMEG_2719-2718). Using genetic manipulation and high-sensitivity GC, we demonstrate that Hyd3 facilitates the evolution of H2 when oxygen is depleted. Combined activity of Hyd2 and Hyd3 was necessary to maintain an optimal NAD+/NADH ratio and enhanced adaptation to and survival of hypoxia. We demonstrate that fermentatively-produced hydrogen can be recycled when fumarate or oxygen become available, suggesting Mycobacterium smegmatis can switch between fermentation, anaerobic respiration, and aerobic respiration. Hydrogen metabolism enables this obligate aerobe to rapidly meet its energetic needs when switching between microoxic and anoxic conditions and provides a competitive advantage in low oxygen environments. PMID:25049411

Various soil amendments and environmental wastes affect the (im)mobilization and phytoavailability of potentially toxic elements in a sewage effluent irrigated sandy soil.

PubMed

Shaheen, Sabry M; Shams, Mohamed S; Khalifa, Mohamed R; El-Dali, Mohamed A; Rinklebe, Jörg

2017-08-01

Contamination of long-term sewage effluent irrigated soils by potentially toxic elements (PTEs) is a serious concern due to its high environmental and health risk. Our scientific hypothesis is that soil amendments can cause contradictory effects on the element mobilization and phytoavailability depending on the type of element and amendment. Therefore, we aimed to assess the impact of the application (1%) of several low cost amendments and environmental wastes on the (im)mobilization, availability, and uptake of Al, Cd, Cr, Cu, Fe, Mn, Ni, and Zn by sorghum (Sorghum bicolor) in a long term sewage effluent irrigated sandy soils collected from Egypt. The used materials include activated charcoal (AC), potassium humate (KH), phosphate rock (PR), phosphogypsum (PG), triple superphosphate (TSP), phosphoric acid (PA), sulfur (S), sugar beet factory lime (SBFL), cement bypass kiln dust (CBD), egg shell (ES), bone mill (BM), brick factory residual (BFR), ceramic powder (CP), and drinking water treatment residual (WTR). The mobilization and availability of the elements in the soil were extracted using NH 4 NO 3 and ammonium bicarbonate- diethylene triamine penta acetic acid (AB-DTPA), respectively. The above-ground biomass samples were analyzed for the elements studied. The results confirmed our hypothesis and concluded that although some amendments like S, PA, and TSP can be used for reducing the plant uptake of Al, Cr, and Fe, they might be used with KH for enhancing the phytoextraction of Cd, Cu, Mn, and Ni. Moreover, several wastes such as BFR and WTR might be used for enhancing the phytoextraction of Al, Cd, Cr, Cu, Fe, and Ni and reducing the uptake of Mn from the studied soil. Although SBFL decreased the plant uptake of Al, Fe, Mn, and Zn, it's increased the plant uptake of Cd, Cu, and Ni. Therefore, the amendments which reduce the plant uptake of an element might be suitable candidates for its immobilization, while the amendments which increase the plant uptake of

Effect of Simulated Weathering and Aging of TNT in Amended Sandy Loam Soil on Toxicity to the Enchytraeid Worm, Enchytreaeus Crypticus

DTIC Science & Technology

2006-05-01

high bioavailability of organic compounds. However, amended SSL soil was analyzed for presence of metabolic transformation products from nitroaromatic...Phillips, C.; Checkai, R. 1999. Comparison of malathion toxicity using enchytraeid reproduction test and earthworm toxicity test in different soil ...OF TNT IN AMENDED SANDY LOAM SOIL ON TOXICITY TO THE ENCHYTRAEID WORM, ENCHYTRAEUS CRYPTICUS Roman G. Kuperman Ronald T. Checkai Michael Simini

Ethylcellulose formulations for controlled release of the herbicide alachlor in a sandy soil.

PubMed

Sopeña, Fátima; Cabrera, Alegría; Maqueda, Celia; Morillo, Esmeralda

2007-10-03

The development of controlled-release formulations of alachlor to diminish its leaching in sandy soils, avoiding groundwater contamination and maintaining its efficacy, was studied. For this purpose, ethylcellulose (EC) microencapsulated formulations (MEFs) of alachlor were prepared under different conditions and applied to soil columns to study their mobility. The results show that in all cases the release into water of alachlor from MEFs was retarded when compared with commercial formulation. Total leaching losses in soil columns were reduced to 59% from 98%. The mobility of alachlor from EC microspheres into soil columns has been greatly diminished in comparison with its current commercial formulation (CF), above all with increasing EC/herbicide ratios. Distribution of alachlor applied as MEFs at different depths in the soil was higher in the soil surface (66.3-81.3% of herbicide applied at the first 12 cm). In contrast, the residues from CF along the complete soil column were only 20.4%. From the results of bioassays, MEFs showed a higher efficacy than CF at 30 days after the treatment. The use of ME formulations could provide an advantage in minimizing the risk of groundwater contamination by alachlor and reducing the application rates, as a result of maintaining the desired concentration of the herbicide in the top soil layer, obtaining longer periods of weed control.

Removal of trichloroethylene (TCE) contaminated soil using a two-stage anaerobic-aerobic composting technique.

PubMed

Ponza, Supat; Parkpian, Preeda; Polprasert, Chongrak; Shrestha, Rajendra P; Jugsujinda, Aroon

2010-01-01

The effect of organic carbon addition on remediation of trichloroethylene (TCE) contaminated clay soil was investigated using a two stage anaerobic-aerobic composting system. TCE removal rate and processes involved were determined. Uncontaminated clay soil was treated with composting materials (dried cow manure, rice husk and cane molasses) to represent carbon based treatments (5%, 10% and 20% OC). All treatments were spiked with TCE at 1,000 mg TCE/kg DW and incubated under anaerobic and mesophillic condition (35 degrees C) for 8 weeks followed by continuous aerobic condition for another 6 weeks. TCE dissipation, its metabolites and biogas composition were measured throughout the experimental period. Results show that TCE degradation depended upon the amount of organic carbon (OC) contained within the composting treatments/matrices. The highest TCE removal percentage (97%) and rate (75.06 micro Mole/kg DW/day) were obtained from a treatment of 10% OC composting matrices as compared to 87% and 27.75 micro Mole/kg DW/day for 20% OC, and 83% and 38.08 micro Mole/kg DW/day for soil control treatment. TCE removal rate was first order reaction kinetics. Highest degradation rate constant (k(1) = 0.035 day(- 1)) was also obtained from the 10% OC treatment, followed by 20% OC (k(1) = 0.026 day(- 1)) and 5% OC or soil control treatment (k(1) = 0.023 day(- 1)). The half-life was 20, 27 and 30 days, respectively. The overall results suggest that sequential two stages anaerobic-aerobic composting technique has potential for remediation of TCE in heavy texture soil, providing that easily biodegradable source of organic carbon is present.

Trace metal pyritization variability in response to mangrove soil aerobic and anaerobic oxidation processes.

PubMed

Machado, W; Borrelli, N L; Ferreira, T O; Marques, A G B; Osterrieth, M; Guizan, C

2014-02-15

The degree of iron pyritization (DOP) and degree of trace metal pyritization (DTMP) were evaluated in mangrove soil profiles from an estuarine area located in Rio de Janeiro (SE Brazil). The soil pH was negatively correlated with redox potential (Eh) and positively correlated with DOP and DTMP of some elements (Mn, Cu and Pb), suggesting that pyrite oxidation generated acidity and can affect the importance of pyrite as a trace metal-binding phase, mainly in response to spatial variability in tidal flooding. Besides these aerobic oxidation effects, results from a sequential extraction analyses of reactive phases evidenced that Mn oxidized phase consumption in reaction with pyrite can be also important to determine the pyritization of trace elements. Cumulative effects of these aerobic and anaerobic oxidation processes were evidenced as factors affecting the capacity of mangrove soils to act as a sink for trace metals through pyritization processes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of organic manure on sorption and degradation of azoxystrobin in soil.

PubMed

Ghosh, Rakesh Kumar; Singh, Neera

2009-01-28

Information on pesticide degradation and factors influencing are important in predicting the levels of pesticide remaining in soils and allow assessment of potential risk associated with exposure. The present study reports the sorption and degradation of azoxystrobin [methyl (E)-2-{2-(6-(2-cyanophenoxy)pyrimidin-4-yloxy)phenyl}-3-methoxyacrylate] in a sandy loam soil. The fungicide was moderately sorbed, and the Freundlich adsorption parameter K(f) (1/n) values in natural and 5% compost-amended soils were 9.31 and 13.72, respectively. Sorption showed hysteresis with 32.5 and 14.7% of sorbed fungicide desorbed from the natural and 5% compost-amended soils, respectively. Azoxystrobin was more persistent in the aerobic soil than the anaerobic soil with half-life values of 107.47 and 62.69 days, respectively. Amendment of compost (5%) to the soil enhanced the degradation of fungicide, and the respective half-life values in aerobic and anaerobic soils were 73.39 and 38.58 days, respectively. Azoxystrobin acid was recovered as the only metabolite of azoxystrobin degradation in soils. Both sunlight and UV light affected the persistence of azoxystrobin with fungicide degraded at a faster rate in UV light than in sunlight. Soil acts as a screen and slows the fungicide degradation under sunlight and UV light.

Fate of CL-20 in sandy soils: degradation products as potential markers of natural attenuation.

PubMed

Monteil-Rivera, Fanny; Halasz, Annamaria; Manno, Dominic; Kuperman, Roman G; Thiboutot, Sonia; Ampleman, Guy; Hawari, Jalal

2009-01-01

Hexanitrohexaazaisowurtzitane (CL-20) is an emerging explosive that may replace the currently used explosives such as RDX and HMX, but little is known about its fate in soil. The present study was conducted to determine degradation products of CL-20 in two sandy soils under abiotic and biotic anaerobic conditions. Biotic degradation was prevalent in the slightly acidic VT soil, which contained a greater organic C content, while the slightly alkaline SAC soil favored hydrolysis. CL-20 degradation was accompanied by the formation of formate, glyoxal, nitrite, ammonium, and nitrous oxide. Biotic degradation of CL-20 occurred through the formation of its denitrohydrogenated derivative (m/z 393 Da) while hydrolysis occurred through the formation of a ring cleavage product (m/z 156 Da) that was tentatively identified as CH(2)=N-C(=N-NO(2))-CH=N-CHO or its isomer N(NO(2))=CH-CH=N-CO-CH=NH. Due to their chemical specificity, these two intermediates may be considered as markers of in situ attenuation of CL-20 in soil.

Comparison of aerobic and anaerobic [3H]leucine incorporation assays for determining pollution-induced bacterial community tolerance in copper-polluted, irrigated soils.

PubMed

Aaen, Karoline Nolsø; Holm, Peter E; Priemé, Anders; Hung, Ngoc Ngo; Brandt, Kristian Koefoed

2011-03-01

Pollution-induced community tolerance (PICT) constitutes a sensitive and ecologically relevant impact parameter in ecotoxicology. We report the development and application of a novel anaerobic [(3) H]leucine incorporation assay and its comparison with the conventional aerobic [(3) H]leucine incorporation assay for PICT detection in soil bacterial communities. Selection of bacterial communities was performed over 42 d in bulk soil microcosms (no plants) and in rice (Oryza sativa) rhizosphere soil mesocosms. The following experimental treatments were imposed using a full factorial design: two soil types, two soil water regimes, and four Cu application rates (0, 30, 120, or 280 µg g(-1)). Bacterial communities in bulk soil microcosms exhibited similar Cu tolerance patterns when assessed by aerobic and anaerobic PICT assays, whereas aerobic microorganisms tended to be more strongly selected for Cu tolerance than anaerobic microorganisms in rhizosphere soil. Despite similar levels of water-extractable Cu, bacterial Cu tolerance was significantly higher in acid sulfate soil than in alluvial soil. Copper amendment selected for significant PICT development in soils subjected to alternate wetting and drying, but not in continuously flooded soils. Our results demonstrate that soil bacterial communities subjected to alternate wetting and drying may be more affected by Cu than bacterial communities subjected to continuous flooding. We conclude that the parallel use of anaerobic and aerobic [(3) H]leucine PICT assays constitutes a valuable improvement over existing procedures for PICT detection in irrigated soils and other redox gradient environments such as sediments and wetlands. Copyright © 2010 SETAC.

Biochar pyrolyzed at two temperatures affects Escherichia coli transport through a sandy soil.

PubMed

Bolster, Carl H; Abit, Sergio M

2012-01-01

The incorporation of biochar into soils has been proposed as a means to sequester carbon from the atmosphere. An added environmental benefit is that biochar has also been shown to increase soil retention of nutrients, heavy metals, and pesticides. The goal of this study was to evaluate whether biochar amendments affect the transport of Escherichia coli through a water-saturated soil. We looked at the transport of three E. coli isolates through 10-cm columns packed with a fine sandy soil amended with 2 or 10% (w/w) poultry litter biochar pyrolyzed at 350 or 700°C. For all three isolates, mixing the high-temperature biochar at a rate of 2% into the soil had no impact on transport behavior. When added at a rate of 10%, a reduction of five orders of magnitude in the amount of E. coli transported through the soil was observed for two of the isolates, and a 60% reduction was observed for the third isolate. Mixing the low-temperature biochar into the soil resulted in enhanced transport through the soil for two of the isolates, whereas no significant differences in transport behavior were observed between the low-temperature and high-temperature biochar amendments for one isolate. Our results show that the addition of biochar can affect the retention and transport behavior of E. coli and that biochar application rate, biochar pyrolysis temperature, and bacterial surface characteristics were important factors determining the transport of E. coli through our test soil. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Dynamics of carbon pools in post-agrogenic sandy soils of southern taiga of Russia.

PubMed

Kalinina, Olga; Goryachkin, Sergey V; Karavaeva, Nina A; Lyuri, Dmitriy I; Giani, Luise

2010-04-26

Until recently, a lot of arable lands were abandoned in many countries of the world and, especially, in Russia, where about half a million square kilometers of arable lands were abandoned in 1961-2007. The soils at these fallows undergo a process of natural restoration (or self-restoration) that changes the balance of soil organic matter (SOM) supply and mineralization. A soil chronosequence study, covering the ecosystems of 3, 20, 55, 100, and 170 years of self-restoration in southern taiga zone, shows that soil organic content of mineral horizons remains relatively stable during the self-restoration. This does not imply, however, that SOM pools remain steady. The C/N ratio of active SOM reached steady state after 55 years, and increased doubly (from 12.5 - 15.6 to 32.2-33.8). As to the C/N ratio of passive SOM, it has been continuously increasing (from 11.8-12.7 to 19.0-22.8) over the 170 years, and did not reach a steady condition. The results of the study imply that soil recovery at the abandoned arable sandy lands of taiga is incredibly slow process. Not only soil morphological features of a former ploughing remained detectable but also the balance of soil organic matter input and mineralization remained unsteady after 170 years of self-restoration.

Dynamics of carbon pools in post-agrogenic sandy soils of southern taiga of Russia

PubMed Central

2010-01-01

Background Until recently, a lot of arable lands were abandoned in many countries of the world and, especially, in Russia, where about half a million square kilometers of arable lands were abandoned in 1961-2007. The soils at these fallows undergo a process of natural restoration (or self-restoration) that changes the balance of soil organic matter (SOM) supply and mineralization. Results A soil chronosequence study, covering the ecosystems of 3, 20, 55, 100, and 170 years of self-restoration in southern taiga zone, shows that soil organic content of mineral horizons remains relatively stable during the self-restoration. This does not imply, however, that SOM pools remain steady. The C/N ratio of active SOM reached steady state after 55 years, and increased doubly (from 12.5 - 15.6 to 32.2-33.8). As to the C/N ratio of passive SOM, it has been continuously increasing (from 11.8-12.7 to 19.0-22.8) over the 170 years, and did not reach a steady condition. Conclusion The results of the study imply that soil recovery at the abandoned arable sandy lands of taiga is incredibly slow process. Not only soil morphological features of a former ploughing remained detectable but also the balance of soil organic matter input and mineralization remained unsteady after 170 years of self-restoration. PMID:20420668

Soil property control of biogeochemical processes beneath two subtropical stormwater infiltration basins

USGS Publications Warehouse

O'Reilly, Andrew M.; Wanielista, Martin P.; Chang, Ni-Bin; Harris, Willie G.; Xuan, Zhemin

2012-01-01

Substantially different biogeochemical processes affecting nitrogen fate and transport were observed beneath two stormwater infiltration basins in north-central Florida. Differences are related to soil textural properties that deeply link hydroclimatic conditions with soil moisture variations in a humid, subtropical climate. During 2008, shallow groundwater beneath the basin with predominantly clayey soils (median, 41% silt+clay) exhibited decreases in dissolved oxygen from 3.8 to 0.1 mg L-1 and decreases in nitrate nitrogen (NO3-–N) from 2.7 mg L-1 to -1, followed by manganese and iron reduction, sulfate reduction, and methanogenesis. In contrast, beneath the basin with predominantly sandy soils (median, 2% silt+clay), aerobic conditions persisted from 2007 through 2009 (dissolved oxygen, 5.0–7.8 mg L-1), resulting in NO3-–N of 1.3 to 3.3 mg L-1 in shallow groundwater. Enrichment of d15N and d18O of NO3- combined with water chemistry data indicates denitrification beneath the clayey basin and relatively conservative NO3- transport beneath the sandy basin. Soil-extractable NO3-–N was significantly lower and the copper-containing nitrite reductase gene density was significantly higher beneath the clayey basin. Differences in moisture retention capacity between fine- and coarse-textured soils resulted in median volumetric gas-phase contents of 0.04 beneath the clayey basin and 0.19 beneath the sandy basin, inhibiting surface/subsurface oxygen exchange beneath the clayey basin. Results can inform development of soil amendments to maintain elevated moisture content in shallow soils of stormwater infiltration basins, which can be incorporated in improved best management practices to mitigate NO3- impacts.

Mitigation of Water Stress on Apple Trees under Rotational Irrigation Conditions by Increasing the Application Rate of Organic Fertilizers to Sandy Soils

NASA Astrophysics Data System (ADS)

Hamed, Lamy Mamdoh Mohamed; Ramadan Eid, Abdelraouf; Mohsmed Rabie Abdellatif Abdelaziz, Adel; Fathy Abdelsalam Essa, El-Sayed

2016-04-01

Egypt, as part of Mediterranean regions, is characterized by irregular and low rainfall amount which varies between (30-150 mm.year-1), and characterized also by high temperature which increase the rate of evapotranspiration from the cultivated soil. On the other hand, New reclaimed soils are mostly occupies around 84 % of total area of Egypt, which is mainly sandy soils. These soils generally characterized by low water capacity holding, soil organic matter, and weak in nutrients retention. Under these conditions which have a great influence on crop production, there is a great needing to increase the crop water use efficiency and increasing of nutrient retention in sandy soils. In this context, two field experiments were carried out on sand soil located in north Cairo-Egypt at the experimental farm of National Research Center, El-NUBARIA, (latitude 30° 30' N, and longitude 30° 19' E). The effect of compost rates on soil hydraulic characteristics, fruit yields, quality traits, and water use efficiency and productivity of apple tree (Apple Anna Cultivar), was studied under deficit irrigation conditions. Four rates of compost [I1: control, I2: 12 ton.ha-1., I3: 24 ton.ha-1., I4: 36 ton.ha-1. and I5:48 ton.ha-1.] were applied under irrigation frequencies of (IF1 :once per week; IF2 :twice per week, IF3 :three times per week). The obtained results indicated that by increasing the application rate of compost, the available water capacity and saturated water content of sandy soil have been enhanced. In the same time, the fruit yield, quality traits and water productivity were increased by increasing the application rate of compost. It is worthy to mention that the I5IF3 treatment gave the highest values of fruit yield, quality traits and water productivity, whereas I1IF1 treatment gave the lowest values of all the above mentioned variables. As result, for apple cultivation in El-NUBARIA region, the recommended rate of compost is 48 ton.ha-1 and irrigation frequency

Experimental studies on the physico-mechanical properties of jet-grout columns in sandy and silty soils

NASA Astrophysics Data System (ADS)

Akin, Muge K.

2016-04-01

The term of ground improvement states to the modification of the engineering properties of soils. Jet-grouting is one of the grouting methods among various ground improvement techniques. During jet-grouting, different textures of columns can be obtained depending on the characteristics of surrounding subsoil as well as the adopted jet-grouting system for each site is variable. In addition to textural properties, strength and index parameters of jet-grout columns are highly affected by the adjacent soil. In this study, the physical and mechanical properties of jet-grout columns constructed at two different sites in silty and sandy soil conditions were determined by laboratory tests. A number of statistical relationships between physical and mechanical properties of soilcrete were established in this study in order to investigate the dependency of numerous variables. The relationship between qu and γd is more reliable for sandy soilcrete than that of silty columns considering the determination coefficients. Positive linear relationships between Vp and γd with significantly high determination coefficients were obtained for the jet-grout columns in silt and sand. The regression analyses indicate that the P-wave velocity is a very dominant parameter for the estimation of physical and mechanical properties of jet-grout columns and should be involved during the quality control of soilcrete material despite the intensive use of uniaxial compressive strength test. Besides, it is concluded that the dry unit weight of jet-grout column is a good indicator of the efficiency of employed operational parameters during jet-grouting.

Regional analysis of groundwater phosphate concentrations under acidic sandy soils: Edaphic factors and water table strongly mediate the soil P-groundwater P relation.

PubMed

Mabilde, Lisa; De Neve, Stefaan; Sleutel, Steven

2017-12-01

Historic long-term P application to sandy soils in NW-Europe has resulted in abundant sorption, saturation and eventually leaching of P from soil to the groundwater. Although many studies recognize the control of site-specific factors like soil texture and phosphate saturation degree (PSD), the regional-scaled relevance of effects exerted by single factors controlling P leaching is unclear. Very large observational datasets of soil and groundwater P content are furthermore required to reveal indirect controls of soil traits through mediating soil variables. We explored co-variation of phreatic groundwater orthophosphate (o-P) concentration and soil factors in sandy soils in Flanders, Belgium. Correlation analyses were complemented with an exploratory model derived using 'path analysis'. Data of oxalate-extractable Al, Fe, P and pH KCl , phosphate sorption capacity (PSC) and PSD in three depth layers (0-30, 30-60, 60-90 cm), topsoil SOC, % clay and groundwater depth (fluctuation) were interpolated to predict soil properties on exact locations of a very extensive net of groundwater monitoring wells. The mean PSD was only poorly correlated to groundwater o-P concentration, indicating the overriding control of other factors in the transport of P to the groundwater. A significant (P < 0.01) positive non-linear relationship was found between groundwater o-P concentrations and pH KCl for all depth layers. Likewise, lower SOC% (P < 0.01) and shallower groundwater level (MHL or MLL) corresponded (P < 0.01) with higher o-P concentrations. Groundwater o-P unexpectedly correlated positively to clay% and path analysis indicated this to be an indirect effect of the groundwater level. Path analysis furthermore indicated an important indirect control of pH on groundwater o-P concentrations and a considerable direct effect of P ox, 0-90 , Al ox, 0-90 and MHL. The fact that groundwater o-P concentration was stronger controlled by soil pH and groundwater table depth than by

[Nutrient contents and microbial populations of aeolian sandy soil in Sanjiangyuan region of Qinghai Province].

PubMed

Lin, Chao-feng; Chen, Zhan-quan; Xue, Quan-hong; Lai, Hang-xian; Chen, Lai-sheng; Zhang, Deng-shan

2007-01-01

Sanjiangyuan region (the headstream of three rivers) in Qinghai Province of China is the highest and largest inland alpine wetland in the world. The study on the nutrient contents and microbial populations of aeolian sandy soils in this region showed that soil organic matter content increased with the evolution of aeolian sand dunes from un-stabilized to stabilized state, being 5.9 and 3.8 times higher in stabilized sand dune than in mobile and semi-stabilized sand dunes, respectively. Soil nitrogen and phosphorus contents increased in line with the amount of organic matter, while potassium content and pH value varied slightly. The microbial populations changed markedly with the development of vegetation, fixing of mobile sand, and increase of soil nutrients. The quantities of soil bacteria, fungi and actinomycetes were 4.0 and 2.8 times, 19.6 and 6.3 times, and 12.4 and 2.6 times higher in stabilized and semi-stabilized sand dunes than in mobile sand dune, respectively, indicating that soil microbial bio-diversity was increased with the evolution of aeolian sand dunes from mobile to stabilized state. In addition, the quantities of soil microbes were closely correlated with the contents of soil organic matter, total nitrogen, and available nitrogen and phosphorus, but not correlated with soil total phosphorus, total and available potassium, or pH value.

Effects of a novel poly (AA-co-AAm)/AlZnFe₂O₄/potassium humate superabsorbent hydrogel nanocomposite on water retention of sandy loam soil and wheat seedling growth.

PubMed

Shahid, Shaukat Ali; Qidwai, Ansar Ahmad; Anwar, Farooq; Ullah, Inam; Rashid, Umer

2012-10-25

A novel poly(acrylic acid-co-acrylamide)AlZnFe₂O₄/potassium humate( )superabsorbent hydrogel nanocomposite (PHNC) was synthesized and its physical properties characterized using SEM, Energy Dispersive X-ray (EDX) and FTIR spectroscopic techniques. Air dried sandy loam soil was amended with 0.1 to 0.4 w/w% of PHNC to evaluate its soil moisture retention attributes. Effect of PHNC amendment on pH, electrical conductivity (EC), porosity, bulk density and hydraulic conductivity of sandy loam soil was also studied. The soil amendment with 0.1 to 0.4 w/w% of PHNC remarkably enhanced the moisture retention at field capacity as compared to the un-amended soils. Seed germination and seedling growth of wheat (Triticum aestivum L.) was considerably increased and a delay by 6-9 days in wilting of seedlings was observed in the soil amended with PHNC, resulting in improved wheat plant establishment and growth.

Genome sequence of "Pedosphaera parvula" Ellin514, an aerobic Verrucomicrobial isolate from pasture soil.

PubMed

Kant, Ravi; van Passel, Mark W J; Sangwan, Parveen; Palva, Airi; Lucas, Susan; Copeland, Alex; Lapidus, Alla; Glavina del Rio, Tijana; Dalin, Eileen; Tice, Hope; Bruce, David; Goodwin, Lynne; Pitluck, Sam; Chertkov, Olga; Larimer, Frank W; Land, Miriam L; Hauser, Loren; Brettin, Thomas S; Detter, John C; Han, Shunsheng; de Vos, Willem M; Janssen, Peter H; Smidt, Hauke

2011-06-01

"Pedosphaera parvula" Ellin514 is an aerobically grown verrucomicrobial isolate from pasture soil. It is one of the few cultured representatives of subdivision 3 of the phylum Verrucomicrobia. Members of this group are widespread in terrestrial environments.

Feasibility of electrokinetic oxygen supply for soil bioremediation purposes.

PubMed

Mena Ramírez, E; Villaseñor Camacho, J; Rodrigo Rodrigo, M A; Cañizares Cañizares, P

2014-12-01

This paper studies the possibility of providing oxygen to a soil by an electrokinetic technique, so that the method could be used in future aerobic polluted soil bioremediation treatments. The oxygen was generated from the anodic reaction of water electrolysis and transported to the soil in a laboratory-scale electrokinetic cell. Two variables were tested: the soil texture and the voltage gradient. The technique was tested in two artificial soils (clay and sand) and later in a real silty soil, and three voltage gradients were used: 0.0 (control), 0.5, and 1.0 V cm(-1). It was observed that these two variables strongly influenced the results. Oxygen transport into the soil was only available in the silty and sandy soils by oxygen diffusion, obtaining high dissolved oxygen concentrations, between 4 and 9 mg L(-1), useful for possible aerobic biodegradation processes, while transport was not possible in fine-grained soils such as clay. Electro-osmotic flow did not contribute to the transport of oxygen, and an increase in voltage gradients produced higher oxygen transfer rates. However, only a minimum fraction of the electrolytically generated oxygen was efficiently used, and the maximum oxygen transport rate observed, approximately 1.4 mgO2 L(-1)d(-1), was rather low, so this technique could be only tested in slow in-situ biostimulation processes for organics removal from polluted soils. Copyright © 2014 Elsevier Ltd. All rights reserved.

Soil property control of biogeochemical processes beneath two subtropical stormwater infiltration basins.

PubMed

O'Reilly, Andrew M; Wanielista, Martin P; Chang, Ni-Bin; Harris, Willie G; Xuan, Zhemin

2012-01-01

Substantially different biogeochemical processes affecting nitrogen fate and transport were observed beneath two stormwater infiltration basins in north-central Florida. Differences are related to soil textural properties that deeply link hydroclimatic conditions with soil moisture variations in a humid, subtropical climate. During 2008, shallow groundwater beneath the basin with predominantly clayey soils (median, 41% silt+clay) exhibited decreases in dissolved oxygen from 3.8 to 0.1 mg L and decreases in nitrate nitrogen (NO-N) from 2.7 mg L to <0.016 mg L, followed by manganese and iron reduction, sulfate reduction, and methanogenesis. In contrast, beneath the basin with predominantly sandy soils (median, 2% silt+clay), aerobic conditions persisted from 2007 through 2009 (dissolved oxygen, 5.0-7.8 mg L), resulting in NO-N of 1.3 to 3.3 mg L in shallow groundwater. Enrichment of δN and δO of NO combined with water chemistry data indicates denitrification beneath the clayey basin and relatively conservative NO transport beneath the sandy basin. Soil-extractable NO-N was significantly lower and the copper-containing nitrite reductase gene density was significantly higher beneath the clayey basin. Differences in moisture retention capacity between fine- and coarse-textured soils resulted in median volumetric gas-phase contents of 0.04 beneath the clayey basin and 0.19 beneath the sandy basin, inhibiting surface/subsurface oxygen exchange beneath the clayey basin. Results can inform development of soil amendments to maintain elevated moisture content in shallow soils of stormwater infiltration basins, which can be incorporated in improved best management practices to mitigate NO impacts. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Leaching and ponding of viral contaminants following land application of biosolids on sandy-loam soil.

PubMed

Wong, Kelvin; Harrigan, Tim; Xagoraraki, Irene

2012-12-15

Much of the land available for application of biosolids is cropland near urban areas. Biosolids are often applied on hay or grassland during the growing season or on corn ground before planting or after harvest in the fall. In this study, mesophilic anaerobic digested (MAD) biosolids were applied at 56,000 L/ha on a sandy-loam soil over large containment lysimeters seeded to perennial covers of orchardgrass (Dactylis glomerata L.), switchgrass (Panicum virgatum), or planted annually to maize (Zea mays L.). Portable rainfall simulators were to maintain the lysimeters under a nearly saturated (90%, volumetric basis) conditions. Lysimeter leachate and surface ponded water samples were collected and analyzed for somatic phage, adenoviruses, and anionic (chloride) and microbial (P-22 bacteriophage) tracers. Neither adenovirus nor somatic phage was recovered from the leachate samples. P-22 bacteriophage was found in the leachate of three lysimeters (removal rates ranged from 1.8 to 3.2 log(10)/m). Although the peak of the anionic tracer breakthrough occurred at a similar pore volume in each lysimeter (around 0.3 pore volume) the peak of P-22 breakthrough varied between lysimeters (<0.1, 0.3 and 0.7 pore volume). The early time to peak breakthrough of anionic and microbial tracers indicated preferential flow paths, presumably from soil cracks, root channels, worm holes or other natural phenomena. The concentration of viral contaminants collected in ponded surface water ranged from 1 to 10% of the initial concentration in the applied biosolids. The die off of somatic phage and P-22 in the surface water was fit to a first order decay model and somatic phage reached background level at about day ten. In conclusion, sandy-loam soils can effectively remove/adsorb the indigenous viruses leached from the land-applied biosolids, but there is a potential of viral pollution from runoff following significant rainfall events when biosolids remain on the soil surface. Copyright �

Chemical contamination of soils in the New York City area following Hurricane Sandy.

PubMed

Mandigo, Amy C; DiScenza, Dana J; Keimowitz, Alison R; Fitzgerald, Neil

2016-10-01

This paper presents a unique data set of lead, arsenic, polychlorinated biphenyl (PCB), and polycyclic aromatic hydrocarbon (PAH) concentrations in soil samples collected from the metropolitan New York City area in the aftermath of Hurricane Sandy. Initial samples were collected by citizen scientists recruited via social media, a relatively unusual approach for a sample collection project. Participants in the affected areas collected 63 usable samples from basements, gardens, roads, and beaches. Results indicate high levels of arsenic, lead, PCBs, and PAHs in an area approximately 800 feet south of the United States Environmental Protection Agency (US EPA) Superfund site at Newtown Creek. A location adjacent to the Gowanus Canal, another Superfund site, was found to have high PCB concentrations. Areas of high PAH contamination tended to be near high traffic areas or next to sites of known contamination. While contamination as a direct result of Hurricane Sandy cannot be demonstrated conclusively, the presence of high levels of contamination close to known contamination sites, evidence for co-contamination, and decrease in number of samples containing measureable amounts of semi-volatile compounds from samples collected at similar locations 9 months after the storm suggest that contaminated particles may have migrated to residential areas as a result of flooding.

Assessment of chemical and biological significance of arsenical compounds in the Maurice River drainage basin (N. J. ). Part III. Transformations in aerobic and anaerobic conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faust, S.D.; Winka, A.J.; Belton, T.

1987-01-01

A quiescent reservoir system revealed the effects of temperature (20/sup 0/C. and 30/sup 0/C), oxygen levels (aerobic and anaerobic) on the arsenic partitioning and interconversion in organic and sandy lake sediments. Temperature had little or no effect on the specie partitioning. In aerobic reservoirs (sandy and organic), the As(V) levels increased, especially in the organic sediment. In the anaerobic reservoir, the organic sediment maintained its level of As(III). The sandy sediment has a predominance of As(V) suggesting something other than the level of oxygen is a significant controlling factor.

Manure Refinement Affects Apple Rhizosphere Bacterial Community Structure: A Study in Sandy Soil

PubMed Central

Zhang, Qiang; Sun, Jian; Liu, Songzhong; Wei, Qinping

2013-01-01

We used DNA-based pyrosequencing to characterize the bacterial community structure of the sandy soil of an apple orchard with different manure ratios. Five manure percentages (5%, 10%, 15%, 20% and 25%) were examined. More than 10,000 valid reads were obtained for each replicate. The communities were composed of five dominant groups (Proteobacteria, Actinobacteria, Chloroflexi, Acidobacteria and Bacteroidetes), of which Proteobacteria content gradually decreased from 41.38% to 37.29% as manure ratio increased from 0% to 25%, respectively. Redundancy analysis showed that 37 classes were highly correlated with manure ratio, 18 of which were positively correlated. Clustering revealed that the rhizosphere samples were grouped into three components: low manure (control, 5%) treatment, medium manure (10%, 15%) treatment and high manure (20%, 25%) treatment. Venn analysis of species types of these three groups revealed that the bacteria community difference was primarily reflected by quantity ratio rather than species variety. Although greater manure content led to higher soil organic matter content, the medium manure improved soil showed the highest urease activity and saccharase activity, while 5% to 20% manure ratio improvement also resulted in higher bacteria diversity than control and 25% manure ratio treatment. Our experimental results suggest that the use of a proper manure ratio results in significantly higher soil enzyme activity and different bacteria community patterns, whereas the use of excessive manure amounts has negative effect on soil quality. PMID:24155909

Active Distribute Temperature Sensing to Estimate Vertical Water Content Variations in a Loamy-Sandy Soil

NASA Astrophysics Data System (ADS)

Ciocca, F.; Van De Giesen, N.; Assouline, S.; Huwald, H.; Hopmans, J. W.; Lunati, I.; Parlange, M. B.

2011-12-01

Optical fibers in combination with Raman scattering measurements (Distributed Temperature Sensor: DTS) have recently become more standard for the measurement of soil temperature. A recently developed technique to measure soil moisture called Active DTS (ADTS) is investigated in this study. ADTS consists of an application of a heat pulse for a fixed duration and power along the metal sheath covering the optical fiber placed in the soil. Soil moisture can be inferred from the increased temperature measured during the heating phase and the subsequent temperature decrease during the cooling phase. We assess this technique for a loamy-sandy soil as part of a field campaign that took place during the 2011 summer at EPFL. The measurements were taken within a weighing lysimeter (2.5 m depth and 1.2 m diameter) using an optical fiber arranged in 15 loops for a total measurement length of 52 m in the top 80 cm of the soil profile. Local soil moistures were simultaneously measured using capacity-based probes. Thermocouples, wrapped around the fiber, are used to account for the effects of the insulating cover surrounding the cable. Heat pulses of various duration and power have been applied for a range of soil moistures. Measurements were taken during periods of drainage and evaporation. The accuracy of the technique for the EPFL 2011 field campaign and the experiment are discussed and the soil moisture measurements are presented.

Study of aliphatic-aromatic copolyester degradation in sandy soil and its ecotoxicological impact.

PubMed

Rychter, Piotr; Kawalec, Michał; Sobota, Michał; Kurcok, Piotr; Kowalczuk, Marek

2010-04-12

Degradation of poly[(1,4-butylene terephthalate)-co-(1,4-butylene adipate)] (Ecoflex, BTA) monofilaments (rods) in standardized sandy soil was investigated. Changes in the microstructure and chemical composition distribution of the degraded BTA samples were evaluated and changes in the pH and salinity of postdegradation soil, as well as the soil phytotoxicity impact of the degradation products, are reported. A macroscopic and microscopic evaluation of the surface of BTA rod samples after specified periods of incubation in standardized soil indicated erosion of the surface of BTA rods starting from the fourth month of their incubation, with almost total disintegration of the incubated BTA material observed after 22 months. However, the weight loss after this period of time was about 50% and only a minor change in the M(w) of the investigated BTA samples was observed, along with a slight increase in the dispersity (from an initial 2.75 up to 4.00 after 22 months of sample incubation). The multidetector SEC and ESI-MS analysis indicated retention of aromatic chain fragments in the low molar mass fraction of the incubated sample. Phytotoxicity studies revealed no visible damage, such as necrosis and chlorosis, or other inhibitory effects, in the following plants: radish, cres, and monocotyledonous oat, indicating that the degradation products of the investigated BTA copolyester are harmless to the tested plants.

Zinc oxide nanoparticles affect carbon and nitrogen mineralization of Phoenix dactylifera leaf litter in a sandy soil.

PubMed

Rashid, Muhammad Imtiaz; Shahzad, Tanvir; Shahid, Muhammad; Ismail, Iqbal M I; Shah, Ghulam Mustafa; Almeelbi, Talal

2017-02-15

We investigated the impact of zinc oxide nanoparticles (ZnO NPs; 1000mgkg -1 soil) on soil microbes and their associated soil functions such as date palm (Phoenix dactylifera) leaf litter (5gkg -1 soil) carbon and nitrogen mineralization in mesocosms containing sandy soil. Nanoparticles application in litter-amended soil significantly decreased the cultivable heterotrophic bacterial and fungal colony forming units (cfu) compared to only litter-amended soil. The decrease in cfu could be related to lower microbial biomass carbon in nanoparticles-litter amended soil. Likewise, ZnO NPs also reduced CO 2 emission by 10% in aforementioned treatment but this was higher than control (soil only). Labile Zn was only detected in the microbial biomass of nanoparticles-litter applied soil indicating that microorganisms consumed this element from freely available nutrients in the soil. In this treatment, dissolved organic carbon and mineral nitrogen were 25 and 34% lower respectively compared to litter-amended soil. Such toxic effects of nanoparticles on litter decomposition resulted in 130 and 122% lower carbon and nitrogen mineralization efficiency respectively. Hence, our results entail that ZnO NPs are toxic to soil microbes and affect their function i.e., carbon and nitrogen mineralization of applied litter thus confirming their toxicity to microbial associated soil functions. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of soil texture on phytoremediation of arsenic-contaminated soils

NASA Astrophysics Data System (ADS)

Pallud, C. E.; Matzen, S. L.; Olson, A.

2015-12-01

Soil arsenic (As) contamination is a global problem, resulting in part from anthropogenic activities, including the use of arsenical pesticides and treated wood, mining, and irrigated agriculture. Phytoextraction using the hyperaccumulating fern Pteris vittata is a promising new technology to remediate soils with shallow arsenic contamination with minimal site disturbance. However, many challenges still lie ahead for a global application of phytoremediation. For example, remediation times using P. vittata are on the order of decades. In addition, most research on As phytoextraction with P. vittata has examined As removal from sandy soils, where As is more available, with little research focusing on As removal from clayey soils, where As is less available. The objective of this study is to determine the effects of soil texture and soil fertilization on As extraction by P. vittata, to optimize remediation efficiency and decrease remediation time under complex field conditions. A field study was established 2.5 years ago in an abandoned railroad grade contaminated with As (average 85.5 mg kg-1) with texture varying from sandy loam to silty clay loam. Organic N, inorganic N, organic P, inorganic P, and compost were applied to separate sub-plots; control ferns were grown in untreated soil. In a parallel greenhouse experiment, ferns were grown in sandy loam soil extracted from the field (180 mg As kg-1), with similar treatments as those used at the field site, plus a high phosphate treatment and treatments with arbuscular mycorrhizal fungi. In the field study, fern mortality was 24% higher in clayey soil than in sandy soil due to waterlogging, while As was primarily associated with sandy soil. Results from the sandy loam soil indicate that soil treatments did not significantly increase As phytoextraction, which was lower in phosphate-treated ferns than in control ferns, both in the field and greenhouse study. Under greenhouse conditions, ferns treated with organic N were

Genome Sequence of "Pedosphaera parvula" Ellin514, an Aerobic Verrucomicrobial Isolate from Pasture Soil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kant, Ravi; Van Passel, Mark W.J.; Palva, Airi

2011-01-01

Pedosphaera parvula Ellin514 is an aerobically grown verrucomicrobial isolate from pasture soil. In contrast to the high abundance of members of Verrucomicrobia subdivision 3 based on molecular surveys in terrestrial environments, Ellin514 is one of the few cultured representatives of this group.

Percolation and transport in a sandy soil under a natural hydraulic gradient

USGS Publications Warehouse

Green, Christopher T.; Stonestrom, David A.; Bekins, Barbara A.; Akstin, Katherine C.; Schulz, Marjorie S.

2005-01-01

Unsaturated flow and transport under a natural hydraulic gradient in a Mediterranean climate were investigated with a field tracer experiment combined with laboratory analyses and numerical modeling. Bromide was applied to the surface of a sandy soil during the dry season. During the subsequent rainy season, repeated sediment sampling tracked the movement of bromide through the profile. Analysis of data on moisture content, matric pressure, unsaturated hydraulic conductivity, bulk density, and soil texture and structure provides insights into parameterization and use of the advective‐dispersive modeling approach. Capturing the gross features of tracer and moisture movement with model simulations required an order‐of‐magnitude increase in laboratory‐measured hydraulic conductivity. Wetting curve characteristics better represented field results, calling into question the routine estimation of hydraulic characteristics based only on drying conditions. Measured increases in profile moisture exceeded cumulative precipitation in early winter, indicating that gains from dew drip can exceed losses from evapotranspiration during periods of heavy (“Tule”) fog. A single‐continuum advective‐dispersive modeling approach could not reproduce a peak of bromide that was retained near the soil surface for over 3 years. Modeling of this feature required slow exchange of solute at a transfer rate of 0.5–1 × 10−4 d−1 with an immobile volume approaching the residual moisture content.

[Characteristics of soil nematode community along an age sequence of sandy desert soil cultivation in a marginal oasis of middle reaches of Heihe River].

PubMed

Wang, Xue-Feng; Su, Yong-Zhong; Yang, Rong

2010-08-01

This paper studied the characteristics of soil nematode community following the conversion of native sandy desert soil to irrigated farmland in a marginal oasis of the middle reaches of Heihe River basin, aimed to approach the bioindicating function of soil nematodes in soil evolution process. A total of 27921 soil nematode individuals were captured, belonging to 25 families and 34 genera. The total number of nematodes increased gradually with increasing age of cultivation. At all sampling sites, bacterivores and plant parasites were the dominant trophic groups, and made up the main parts of nematode community in oasis farmland. Through the analysis of the evenness index (J) and dominance index (lambda) of nematode community, the ecosystems were found to be fragile for the farmlands having cultivated for 0, 10, and > 50 years. The maturity index MI2-5 and MMI decreased with increasing cultivation age, suggesting that the practice of agricultural use enhanced the disturbance on farmland. The soil properties changed significantly after 10 years of cultivation, which was at a significant change stage for the structure stability of soil ecosystems. The characteristics of soil nematode community could be used as the bioindicator of soil evolution following the conversion of native desert soil to irrigated farmland.

Phytotoxicity of nitroaromatic energetic compounds freshly amended or weathered and aged in sandy loam soil.

PubMed

Rocheleau, Sylvie; Kuperman, Roman G; Martel, Majorie; Paquet, Louise; Bardai, Ghalib; Wong, Stephen; Sarrazin, Manon; Dodard, Sabine; Gong, Ping; Hawari, Jalal; Checkai, Ronald T; Sunahara, Geoffrey I

2006-01-01

The toxicities of 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitrobenzene (TNB), 2,4-dinitrotoluene (2,4-DNT), and 2,6-dinitrotoluene (2,6-DNT) to terrestrial plants alfalfa (Medicago sativa L.), Japanese millet (Echinochloa crusgalli L.), and perennial ryegrass (Lolium perenne L.) were determined in Sassafras sandy loam soil using seedling emergence, fresh shoot, and dry mass measurement endpoints. A 13-week weathering and aging of energetic materials in soils, which included wetting and drying cycles, and exposure to sunlight of individual soil treatments, was incorporated into the study design to better reflect the soil exposure conditions in the field than toxicity determinations in freshly amended soils. Definitive toxicity tests showed that dinitrotoluenes were more phytotoxic for all plant species in freshly amended treatments based on EC20 values for dry shoot ranging from 3 to 24mgkg(-1) compared with values for TNB or TNT ranging from 43 to 62mgkg(-1). Weathering and aging of energetic materials (EMs) in soil significantly decreased the toxicity of TNT, TNB or 2,6-DNT to Japanese millet or ryegrass based on seedling emergence, but significantly increased the toxicity of all four EMs to all three plant species based on shoot growth. Exposure of the three plant species to relatively low concentrations of the four compounds initially stimulated plant growth before the onset of inhibition at greater concentrations (hormesis).

Influence of biochar on the physical, chemical and retention properties of an amended sandy soil

NASA Astrophysics Data System (ADS)

Baiamonte, Giorgio; De Pasquale, Claudio; Parrino, Francesco; Crescimanno, Giuseppina

2017-04-01

Soil porosity plays an important role in soil-water retention and water availability to crops, potentially affecting both agricultural practices and environmental sustainability. The pore structure controls fluid flow and transport through the soil, as well as the relationship between the properties of individual minerals and plants. Moreover, the anthropogenic pressure on soil properties has produced numerous sites with extensive desertification process close to residential areas. Biochar (biologically derived charcoal) is produced by pyrolysis of biomasses under low oxygen conditions, and it can be applied for recycling organic waste in soils and increase soil fertility, improving soil structure and enhancing soil water storage and soil water movement. Soil application of biochar might have agricultural, environmental and sustainability advantages over the use of organic manures or compost, as it is a porous material with a high inner surface area. The main objectives of the present study were to investigate the possible application of biochar from forest residues, derived from mechanically chipped trunks and large branches of Abies alba M., Larix decidua Mill., Picea excelsa L., Pinus nigra A. and Pinus sylvestris L. pyrolysed at 450 °C for 48h, to improve soil structural and hydraulic properties (achieving a stabilization of soil). Different amount of biochar were added to a desertic sandy soil, and the effect on soil porosity water retention and water available to crops were investigated. The High Energy Moisture Characteristic (HEMC) technique was applied to investigate soil-water retention at high-pressure head levels. The adsorption and desorption isotherms of N2 on external surfaces were also determined in order to investigate micro and macro porosity ratio. Both the described model of studies on adsorption-desorption experiments with the applied isotherms model explain the increasing substrate porosity with a particular attention to the macro and micro

Spectroscopic characterization of organic matter of a soil and vinasse mixture during aerobic or anaerobic incubation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doelsch, Emmanuel; Masion, Armand; Cazevieille, Patrick

2009-06-15

Mineralization potentials are often used to classify organic wastes. These methods involve measuring CO{sub 2} production during batch experiments, so variations in chemical compounds are not addressed. Moreover, the physicochemical conditions are not monitored during the reactions. The present study was designed to address these deficiencies. Incubations of a mixture of soil and waste (vinasse at 20% dry matter from a fermentation industry) were conducted in aerobic and anaerobic conditions, and liquid samples obtained by centrifugation were collected at 2 h, 1 d and 28 d. Dissolved organic carbon (DOC) patterns highlighted that: there was a 'soil effect' which increasedmore » organic matter (OM) degradation in all conditions compared to vinasse incubated alone; and OM degradation was faster under aerobic conditions since 500 mg kg{sup -1} of C remained after aerobic incubation, as compared to 4000 mg kg{sup -1} at the end of the anaerobic incubation period. No changes were detected by Fourier transform infrared spectroscopy (FTIR) between 2 h and 1 d incubation. At 28 days incubation, the FTIR signal of the aerobic samples was deeply modified, thus confirming the high OM degradation. Under anaerobic conditions, the main polysaccharide contributions ({nu}(C-O)) disappeared at 1000 and 1200 cm{sup -1}, as also confirmed by the {sup 13}C NMR findings. Under aerobic incubation, a 50% decrease in the polysaccharide proportion was observed. Under anaerobic conditions, significant chemical modifications of the organic fraction were detected, namely formation of low molecular weight organic acids.« less

Aerobic Degradation of N-Methyl-4-Nitroaniline (MNA) by Pseudomonas sp. Strain FK357 Isolated from Soil

PubMed Central

Khan, Fazlurrahman; Vyas, Bhawna; Pal, Deepika; Cameotra, Swaranjit Singh

2013-01-01

N-Methyl-4-nitroaniline (MNA) is used as an additive to lower the melting temperature of energetic materials in the synthesis of insensitive explosives. Although the biotransformation of MNA under anaerobic condition has been reported, its aerobic microbial degradation has not been documented yet. A soil microcosms study showed the efficient aerobic degradation of MNA by the inhabitant soil microorganisms. An aerobic bacterium, Pseudomonas sp. strain FK357, able to utilize MNA as the sole carbon, nitrogen, and energy source, was isolated from soil microcosms. HPLC and GC-MS analysis of the samples obtained from growth and resting cell studies showed the formation of 4-nitroaniline (4-NA), 4-aminophenol (4-AP), and 1, 2, 4-benzenetriol (BT) as major metabolic intermediates in the MNA degradation pathway. Enzymatic assay carried out on cell-free lysates of MNA grown cells confirmed N-demethylation reaction is the first step of MNA degradation with the formation of 4-NA and formaldehyde products. Flavin-dependent transformation of 4-NA to 4-AP in cell extracts demonstrated that the second step of MNA degradation is a monooxygenation. Furthermore, conversion of 4-AP to BT by MNA grown cells indicates the involvement of oxidative deamination (release of NH2 substituent) reaction in third step of MNA degradation. Subsequent degradation of BT occurs by the action of benzenetriol 1, 2-dioxygenase as reported for the degradation of 4-nitrophenol. This is the first report on aerobic degradation of MNA by a single bacterium along with elucidation of metabolic pathway. PMID:24116023

Aerobic degradation of N-methyl-4-nitroaniline (MNA) by Pseudomonas sp. strain FK357 isolated from soil.

PubMed

Khan, Fazlurrahman; Vyas, Bhawna; Pal, Deepika; Cameotra, Swaranjit Singh

2013-01-01

N-Methyl-4-nitroaniline (MNA) is used as an additive to lower the melting temperature of energetic materials in the synthesis of insensitive explosives. Although the biotransformation of MNA under anaerobic condition has been reported, its aerobic microbial degradation has not been documented yet. A soil microcosms study showed the efficient aerobic degradation of MNA by the inhabitant soil microorganisms. An aerobic bacterium, Pseudomonas sp. strain FK357, able to utilize MNA as the sole carbon, nitrogen, and energy source, was isolated from soil microcosms. HPLC and GC-MS analysis of the samples obtained from growth and resting cell studies showed the formation of 4-nitroaniline (4-NA), 4-aminophenol (4-AP), and 1, 2, 4-benzenetriol (BT) as major metabolic intermediates in the MNA degradation pathway. Enzymatic assay carried out on cell-free lysates of MNA grown cells confirmed N-demethylation reaction is the first step of MNA degradation with the formation of 4-NA and formaldehyde products. Flavin-dependent transformation of 4-NA to 4-AP in cell extracts demonstrated that the second step of MNA degradation is a monooxygenation. Furthermore, conversion of 4-AP to BT by MNA grown cells indicates the involvement of oxidative deamination (release of NH2 substituent) reaction in third step of MNA degradation. Subsequent degradation of BT occurs by the action of benzenetriol 1, 2-dioxygenase as reported for the degradation of 4-nitrophenol. This is the first report on aerobic degradation of MNA by a single bacterium along with elucidation of metabolic pathway.

Transport of E. coli in a sandy soil as impacted by depth to water table.

PubMed

Stall, Christopher; Amoozegar, Aziz; Lindbo, David; Graves, Alexandria; Rashash, Diana

2014-01-01

Septic systems are considered a source of groundwater contamination. In the study described in this article, the fate of microbes applied to a sandy loam soil from North Carolina coastal plain as impacted by water table depth was studied. Soil materials were packed to a depth of 65 cm in 17 columns (15-cm diameter), and a water table was established at 30, 45, and 60 cm depths using five replications. Each day, 200 mL of an artificial septic tank effluent inoculated with E. coli were applied to the top of each column, a 100-mL sample was collected at the water table level and analyzed for E. coli, and 100 mL was drained from the bottom to maintain the water table. Two columns were used as control and received 200 mL/day of sterilized effluent. Neither 30 nor 45 cm of unsaturated soil was adequate to attenuate bacterial contamination, while 60 cm of separation appeared to be sufficient. Little bacterial contamination moved with the water table when it was lowered from 30 to 60 cm.

Microbiological characteristics of a sandy loam soil exposed to tebuconazole and lambda-cyhalothrin under laboratory conditions.

PubMed

Cycoń, M; Piotrowska-Seget, Z; Kaczyńska, A; Kozdrój, J

2006-11-01

Changes in microbiological properties of a sandy loam soil in response to the addition of different concentrations of fungicide tebuconazole and pyrethroid insecticide lambda-cyhalothrin were assessed under laboratory conditions. To ascertain these changes, the potentially active soil microbial biomass, concentrations of ammonium and nitrate ions, numbers of total culturable bacteria, fungi, nitrogen-fixing bacteria, nitrifying and denitrifying bacteria were determined. Substrate-induced respiration (SIR) increased with time in both control (ranged from 13.7 to 23.7 mg/O(2)/kg(-1)/dry soil/h(-1)) and pesticide treated soil portions. For both pesticides, SIR values ranged from 12-13 to 23-25 mg/O(2)/kg(-1)/dry soil/h(-1) on days 1 and 28, respectively. Also, concentrations of nitrate and ammonium ions, numbers of total culturable bacteria, denitrifying bacteria, nitrogen-fixing bacteria (for the insecticide) and fungi (for the insecticide) were either unaffected or even stimulated by the pesticide treatments. The adverse impacts of the pesticides were observed for nitrate concentrations (on days 1 or 7), numbers of nitrifying bacteria (on day 1), denitrifying bacteria (for the insecticide on days 1 and 14), nitrogen-fixing bacteria (for tebuconazole on day 1) as well as numbers of fungi in tebuconazole-treated soil (on days 1 and 14).

Isolation and characterization of aerobic anoxygenic phototrophs from exposed soils from the Sør Rondane Mountains, East Antarctica.

PubMed

Tahon, Guillaume; Willems, Anne

2017-09-01

This study investigated the culturable aerobic phototrophic bacteria present in soil samples collected in the proximity of the Belgian Princess Elisabeth Station in the Sør Rondane Mountains, East Antarctica. Until recently, only oxygenic phototrophic bacteria (Cyanobacteria) were well known from Antarctic soils. However, more recent non-cultivation-based studies have demonstrated the presence of anoxygenic phototrophs and, particularly, aerobic anoxygenic phototrophic bacteria in these areas. Approximately 1000 isolates obtained after prolonged incubation under different growth conditions were studied and characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Representative strains were identified by sequence analysis of 16S rRNA genes. More than half of the isolates grouped among known aerobic anoxygenic phototrophic taxa, particularly with Sphingomonadaceae, Methylobacterium and Brevundimonas. In addition, a total of 330 isolates were tested for the presence of key phototrophy genes. While rhodopsin genes were not detected, multiple isolates possessed key genes of the bacteriochlorophyll synthesis pathway. The majority of these potential aerobic anoxygenic phototrophic strains grouped with Alphaproteobacteria (Sphingomonas, Methylobacterium, Brevundimonas and Polymorphobacter). Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

Effects of foliage litter of a pioneer shrub (Artemisia halodendron) on germination from the soil seedbank in a semi-arid sandy grassland in China.

PubMed

Luo, Yongqing; Zhao, Xueyong; Li, Yuqiang; Wang, Tao

2017-11-01

Vegetation recovery during succession is an important process for ecological restoration of the soil, especially in degraded sandy land. However, the driving mechanisms, such as how a pioneer species competes with other species, is uncertain. In China's Horqin Sandy Land, Artemisia halodendron is an important shrub that is common on semi-fixed dunes, where it replaces Agriophyllum squarrosum during succession, and is an important indicator species of the second stage of dune stabilization. However, how it outcompetes other species is still unclear. In this study, we conducted a seed bank germination experiment using soil from the native habitats of A. halodendron on semi-fixed dunes. We covered the soil with foliage litter of A. halodendron at a range of concentrations. Seed germination and seedling growth were strongly affected by the foliage litter. Seed germination and seedling growth were not harmed by a low concentration (≤50 g m -2 ) of the foliage litter but severely inhibited by high concentrations (≥100 g m -2 ). Strong allelopathy, indicated by decreased germination, increased seedling loss, and decreased plant biomass, appeared during the later stages of germination (after about 20 days of incubation). Our results suggest that as a pioneer shrub during the vegetation succession that occurs during dune stabilization, A. halodendron outcompeted other species through the allelopathic effect of its foliage litter. This helps to explain the patchy distribution and heterogeneity of vegetation communities in the Horqin Sandy Land.

Bioremediation of soil contaminated by dichlorodiphenyltrichloroethane with the use of aerobic strain Rhodococcus wratislaviensis Ch628

NASA Astrophysics Data System (ADS)

Egorova, D. O.; Farafonova, V. V.; Shestakova, E. A.; Andreyev, D. N.; Maksimov, A. S.; Vasyanin, A. N.; Buzmakov, S. A.; Plotnikova, E. G.

2017-10-01

The concentration of dichlorodiphenyltrichloroethane (DDT) was determined in a sandy soil of specially Protected Natural Area Osinskaya Lesnaya Dacha (Perm region) 45 years after the last application of the insecticide in this area. The concentration of DDT in the soil exceeded the maximum permissible concentration by 250 times and reached 25.05 mg/kg of soil. Under the conditions of model experiment, efficient decontamination of the soil was recorded in the system with the introduced strain Rhodococcus wratislaviensis Ch628; the DDT concentration decreased by 99.7% and equaled 0.07 mg/kg. The process of DDT degradation proceeded slower in the model soil system with autochthonous microbial complex. In this case, 58.2% DDT degraded in 70 days, and the final concentration was 10.47 mg/kg. The soil lost its toxicity for animal and plant test objects by the end of the experiment only in the model system containing the R. wratislaviensis Ch628 strain.

Effects of soil moisture on dust emission from 2011 to 2015 observed over the Horqin Sandy Land area, China

NASA Astrophysics Data System (ADS)

Ju, Tingting; Li, Xiaolan; Zhang, Hongsheng; Cai, Xuhui; Song, Yu

2018-06-01

Using the observational data of dust concentrations and meteorological parameters from 2011 to 2015, the effects of soil moisture and air humidity on dust emission were studied at long (monthly) and short (several days or hours) time scales over the Horqin Sandy Land area, Inner Mongolia of China. The results show that the monthly mean dust concentrations and dust fluxes within the near-surface layer had no obvious relationship with the monthly mean soil moisture content but had a slightly negative correlation with monthly mean air relative humidity from 2011 to 2015. The daily mean soil moisture exhibited a significantly negative correlation with the daily mean dust concentrations and dust fluxes, as soil moisture changed obviously. However, such negative correlation between soil moisture and dust emission disappeared on dust blowing days. Additionally, the effect of soil moisture on an important parameter for dust emission, the threshold friction velocity (u∗t), was investigated during several saltation-bombardment and/or aggregation-disintegration dust emission (SADE) events. Under dry soil conditions, the values of u∗t were not influenced by soil moisture content; however, when the soil moisture content was high, the values of u∗t increased with increasing soil moisture content.

Community Structure of Active Aerobic Methanotrophs in Red Mangrove (Kandelia obovata) Soils Under Different Frequency of Tides.

PubMed

Shiau, Yo-Jin; Cai, Yuanfeng; Lin, Yu-Te; Jia, Zhongjun; Chiu, Chih-Yu

2018-04-01

Methanotrophs are important microbial communities in coastal ecosystems. They reduce CH 4 emission in situ, which is influenced by soil conditions. This study aimed to understand the differences in active aerobic methanotrophic communities in mangrove forest soils experiencing different inundation frequency, i.e., in soils from tidal mangroves, distributed at lower elevations, and from dwarf mangroves, distributed at higher elevations. Labeling of pmoA gene of active methanotrophs using DNA-based stable isotope probing (DNA-SIP) revealed that methanotrophic activity was higher in the dwarf mangrove soils than in the tidal mangrove soils, possibly because of the more aerobic soil conditions. Methanotrophs affiliated with the cluster deep-sea-5 belonging to type Ib methanotrophs were the most dominant methanotrophs in the fresh mangrove soils, whereas type II methanotrophs also appeared in the fresh dwarf mangrove soils. Furthermore, Methylobacter and Methylosarcina were the most important active methanotrophs in the dwarf mangrove soils, whereas Methylomonas and Methylosarcina were more active in the tidal mangrove soils. High-throughput sequencing of the 16S ribosomal RNA (rRNA) gene also confirmed similar differences in methanotrophic communities at the different locations. However, several unclassified methanotrophic bacteria were found by 16S rRNA MiSeq sequencing in both fresh and incubated mangrove soils, implying that methanotrophic communities in mangrove forests may significantly differ from the methanotrophic communities documented in previous studies. Overall, this study showed the feasibility of 13 CH 4 DNA-SIP to study the active methanotrophic communities in mangrove forest soils and revealed differences in the methanotrophic community structure between coastal mangrove forests experiencing different tide frequencies.

Effects of biochars on the bioaccessibility of phenanthrene/pyrene/zinc/lead and microbial community structure in a soil under aerobic and anaerobic conditions.

PubMed

Ni, Ni; Shi, Renyong; Liu, Zongtang; Bian, Yongrong; Wang, Fang; Song, Yang; Jiang, Xin

2018-01-01

The immobilization of co-contaminants of organic and inorganic pollutants by biochar is an efficient remediation strategy. However, the effect of biochar amendments on the bioaccessibility of the co-contaminants in dry versus flooded soils has rarely been compared. In batch experiments, bamboo-derived biochar (BB) had a higher sorption capacity for phenanthrene (Phe)/pyrene (Pyr)/zinc (Zn) than corn straw-derived biochar (CB), while CB had a higher sorption capacity for lead (Pb) than BB. After 150days of incubation, the amendments of 2% CB, 0.5% BB and 2% BB effectively suppressed the dissipation and reduced the bioaccessibility of Phe/Pyr by 15.65%/18.02%, 17.07%/18.31% and 25.43%/27.11%, respectively, in the aerobic soils. This effectiveness was more significant than that in the anaerobic soils. The accessible Zn/Pb concentrations were also significantly lower in the aerobic soils than in the anaerobic soils, regardless of treatments. The Gram-negative bacterial biomass and the Shannon-Weaver index in the aerobic soil amended with 2% CB were the highest. The soil microbial community structure was jointly affected by changes in the bioaccessibility of the co-contaminants and the soil physiochemical properties caused by biochar amendments under the two conditions. Therefore, dry land farming may be more reliable than paddy soil cultivation at reducing the bioaccessibility of Phe/Pyr/Zn/Pb and enhancing the soil microbial diversity in the short term. Copyright © 2017. Published by Elsevier B.V.

Does thermal carbonization (Biochar) of organic material increase more merits for their amendments of sandy soil?

NASA Astrophysics Data System (ADS)

Wu, Y.; Xu, G.; Sun, J. N.; Shao, H. B.

2014-02-01

Organic materials (e.g. furfural residue) are generally believed to improve the physical and chemical properties of the soils with low fertility. Recently, biochar have been received more attention as a possible measure to improve the carbon balance and improve soil quality in some degraded soils. However, little is known about their different amelioration of a sandy saline soil. In this study, 56d incubation experiment was conducted to evaluate the influence of furfural and its biochar on the properties of saline soil. The results showed that both furfural and biochar greatly reduced pH, increased soil organic carbon (SOC) content and cation exchange capacity (CEC), and enhanced the available phosphorus (P) in the soil. Furfural is more efficient than biochar in reducing pH: 5% furfural lowered the soil pH by 0.5-0.8 (soil pH: 8.3-8.6), while 5% biochar decreased by 0.25-0.4 due to the loss of acidity in pyrolysis process. With respect to available P, 5% of the furfural addition increased available P content by 4-6 times in comparison to 2-5 times with biochar application. In reducing soil exchangeable sodium percentage (ESP), biochar is slightly superior to furfural because soil ESP reduced by 51% and 43% with 5% furfural and 5% biochar addition at the end of incubation. In addition, no significant differences were observed between furfural and biochar about their capacity to retain N, P in leaching solution and to increase CEC in soil. These facts may be caused by the relatively short incubation time. In general, furfural and biochar have different amendments depending on soil properties: furfural was more effectively to decrease pH and to increase available P, whereas biochar played a more important role in increasing SOC and reducing ESP of saline soil.

Transport and Retention of Toxoplasma gondii Oocysts in Loamy Sand and Sandy Loam Soils

NASA Astrophysics Data System (ADS)

Kinsey, E. N.; Korte, C.; L'Ollivier, C.; Dubey, J. P.; Aurélien, D.; Darnault, C. J. G.

2016-12-01

Toxoplasma gondii is one of the most prevalent parasites affecting warm-blooded animals and humans. It has a complex life cycle that involves a wide variety of intermediate hosts with felids as a definitive host. Humans may contract it through consumption of infected, undercooked meat or by water or food sources contaminated with the oocyst form of the parasite. Infection of pregnant women can cause stillbirth, neurological effects or blindness. Because of the prevalence of cats, including on farms where oocyst-contaminated cat feces, animal feed, soil and water have been found, T. gondii is spread almost throughout the entire globe. It has been implicated or suspected in waterborne infections since the 1990s. This study aims to characterize the transport and retention of T. gondii oocysts in field soils. The four soils used were collected from fallow and cultivated fields in Illinois and Utah, USA. They are classified as loamy sands and sandy loams. Soil columns were subjected to continuous artificial rainfall until they reached steady state at which point pulses that included 2.5 million T. gondii oocysts (Me49 strain) and KBr as a tracer were added. After the pulse infiltrated, continuous rainfall was resumed. Rain applied all columns was a 1 mM KCl solution. Leachate samples were collected, analyzed using qPCR for T. gondii and bromide ions and breakthrough curves were produced. Soil was sliced into 1 to 2 cm sections, for which water content and T. gondii concentration were measured to access degree of saturation and oocyst retention.

Quasi 3D modelling of water flow in the sandy soil

NASA Astrophysics Data System (ADS)

Rezaei, Meisam; Seuntjens, Piet; Joris, Ingeborg; Boënne, Wesley; De Pue, Jan; Cornelis, Wim

2016-04-01

Monitoring and modeling tools may improve irrigation strategies in precision agriculture. Spatial interpolation is required for analyzing the effects of soil hydraulic parameters, soil layer thickness and groundwater level on irrigation management using hydrological models at field scale. We used non-invasive soil sensor, a crop growth (LINGRA-N) and a soil hydrological model (Hydrus-1D) to predict soil-water content fluctuations and crop yield in a heterogeneous sandy grassland soil under supplementary irrigation. In the first step, the sensitivity of the soil hydrological model to hydraulic parameters, water stress, crop yield and lower boundary conditions was assessed after integrating models at one soil column. Free drainage and incremental constant head conditions were implemented in a lower boundary sensitivity analysis. In the second step, to predict Ks over the whole field, the spatial distributions of Ks and its relationship between co-located soil ECa measured by a DUALEM-21S sensor were investigated. Measured groundwater levels and soil layer thickness were interpolated using ordinary point kriging (OK) to a 0.5 by 0.5 m in aim of digital elevation maps. In the third step, a quasi 3D modelling approach was conducted using interpolated data as input hydraulic parameter, geometric information and boundary conditions in the integrated model. In addition, three different irrigation scenarios namely current, no irrigation and optimized irrigations were carried out to find out the most efficient irrigation regime. In this approach, detailed field scale maps of soil water stress, water storage and crop yield were produced at each specific time interval to evaluate the best and most efficient distribution of water using standard gun sprinkler irrigation. The results show that the effect of the position of the groundwater level was dominant in soil-water content prediction and associated water stress. A time-dependent sensitivity analysis of the hydraulic

Lead and cadmium interactions in Cynodon nlemfuensis and sandy soil subjected to treated wastewater application under greenhouse conditions

NASA Astrophysics Data System (ADS)

Madyiwa, Simon; Chimbari, Moses John; Schutte, Frederik

Pb and Cd are known to influence each other’s uptake by some plants when the two metals exist in the soil in significant amounts. This influence may be beneficial if it reduces uptake of metal by plants but may be detrimental if it increases uptake of the metal. This study was carried out to investigate the interaction of Pb and Cd in sandy soils and Cynodon nlemfluensis (star grass). Star grass was grown under greenhouse conditions in 33 fertilized pots containing sandy soils. Three weeks after planting the grass the pots were randomly assigned to the following treatments replicated three times; (a) application of three varying concentrations of Pb or Cd in addition to effluent and sludge, (b) application of three varying concentrations of combined Pb and Cd in addition to effluent and sludge, (c) application of water and (d) application of only effluent and sludge. Analysis of grass samples was done 45 and 90 days after addition of Pb and Cd to pots and that of the soil was done 90 days after addition of Pb and Cd to pots. The log normal mean level (in mg/kg) of Pb detected in the soil was 1.75 and that of Cd was 0.057 in mixed treatments while for single treatments the levels were 1.67 for Pb and 0.03 for Cd. The presence of Cd in the soil had no effect on the bio-available level of Pb but Pb significantly ( p < 0.05) increased the bio-available concentration of Cd. The log normal mean levels of Pb in grass re-growth from mixed treatment was 1.68 and that of Cd was 0.57 while the values for single treatments were 1.47 for Pb and 0.31 for Cd. There was no significant change in the level of uptake of Pb between single treatments and mixed treatments. However, Pb significantly increased uptake of Cd in mixed treatments compared to single treatments ( p < 0.05). The results of this study indicate that co-presence of Pb and Cd may have the detrimental effect of increasing uptake of Cd in star grass.

Reorganization of vegetation, hydrology and soil carbon after permafrost degradation across heterogeneous boreal landscapes

USGS Publications Warehouse

Jorgenson, M. Torre; Harden, Jennifer; Kanevskiy, Mikhail; O'Donnell, Jonathan; Wickland, Kim; Ewing, Stephanie; Manies, Kristen; Zhuang, Qianlai; Shur, Yuri; Striegl, Robert G.; Koch, Joshua C.

2013-01-01

The diversity of ecosystems across boreal landscapes, successional changes after disturbance and complicated permafrost histories, present enormous challenges for assessing how vegetation, water and soil carbon may respond to climate change in boreal regions. To address this complexity, we used a chronosequence approach to assess changes in vegetation composition, water storage and soil organic carbon (SOC) stocks along successional gradients within four landscapes: (1) rocky uplands on ice-poor hillside colluvium, (2) silty uplands on extremely ice-rich loess, (3) gravelly–sandy lowlands on ice-poor eolian sand and (4) peaty–silty lowlands on thick ice-rich peat deposits over reworked lowland loess. In rocky uplands, after fire permafrost thawed rapidly due to low ice contents, soils became well drained and SOC stocks decreased slightly. In silty uplands, after fire permafrost persisted, soils remained saturated and SOC decreased slightly. In gravelly–sandy lowlands where permafrost persisted in drier forest soils, loss of deeper permafrost around lakes has allowed recent widespread drainage of lakes that has exposed limnic material with high SOC to aerobic decomposition. In peaty–silty lowlands, 2–4 m of thaw settlement led to fragmented drainage patterns in isolated thermokarst bogs and flooding of soils, and surface soils accumulated new bog peat. We were not able to detect SOC changes in deeper soils, however, due to high variability. Complicated soil stratigraphy revealed that permafrost has repeatedly aggraded and degraded in all landscapes during the Holocene, although in silty uplands only the upper permafrost was affected. Overall, permafrost thaw has led to the reorganization of vegetation, water storage and flow paths, and patterns of SOC accumulation. However, changes have occurred over different timescales among landscapes: over decades in rocky uplands and gravelly–sandy lowlands in response to fire and lake drainage, over decades to

Bioavailability and chronic toxicity of bismuth citrate to earthworm Eisenia andrei exposed to natural sandy soil.

PubMed

Omouri, Zohra; Hawari, Jalal; Fournier, Michel; Robidoux, Pierre Yves

2018-01-01

The present study describes bioavailability and chronic effects of bismuth to earthworms Eisenia andrei using OECD reproduction test. Adult earthworms were exposed to natural sandy soil contaminated artificially by bismuth citrate. Average total concentrations of bismuth in soil recovered by HNO 3 digestion ranged from 75 to 289mg/kg. Results indicate that bismuth decreased significantly all reproduction parameters of Eisenia andrei at concentrations ≥ 116mg/kg. However, number of hatched cocoons and number of juveniles seem to be more sensitive than total number of cocoons, as determined by IC 50 ; i.e., 182, 123 and > 289mg/kg, respectively. Bismuth did not affect Eisenia andrei growth and survival, and had little effect on phagocytic efficiency of coelomocytes. The low immunotoxicity effect might be explained by the involvement of other mechanisms i.e. bismuth sequestered by metal-binding compounds. After 28 days of exposure bismuth concentrations in earthworms tissue increased with increasing bismuth concentrations in soil reaching a stationary state of 21.37mg/kg dry tissue for 243mg Bi/kg dry soil total content. Data indicate also that after 56 days of incubation the average fractions of bismuth available extracted by KNO 3 aqueous solution in soil without earthworms varied from 0.0051 to 0.0229mg/kg, while in soil with earthworms bismuth concentration ranged between 0.310-1.347mg/kg dry soil. We presume that mucus and chelating agents produced by earthworms and by soil or/and earthworm gut microorganisms could explain this enhancement, as well as the role of dermal and ingestion routes of earthworms uptake to soil contaminant. Copyright © 2017 Elsevier Inc. All rights reserved.

Aerobic composting reduces antibiotic resistance genes in cattle manure and the resistome dissemination in agricultural soils.

PubMed

Gou, Min; Hu, Hang-Wei; Zhang, Yu-Jing; Wang, Jun-Tao; Hayden, Helen; Tang, Yue-Qin; He, Ji-Zheng

2018-01-15

Composting has been suggested as a potential strategy to eliminate antibiotic residues and pathogens in livestock manure before its application as an organic fertilizer in agro-ecosystems. However, the impacts of composting on antibiotic resistance genes (ARGs) in livestock manure and their temporal succession following the application of compost to land are not well understood. We examined how aerobic composting affected the resistome profiles of cattle manure, and by constructing laboratory microcosms we compared the effects of manure and compost application to agricultural soils on the temporal succession of a wide spectrum of ARGs. The high-throughput quantitative PCR array detected a total of 144 ARGs across all the soil, manure and compost samples, with Macrolide-Lincosamide-Streptogramin B, aminoglycoside, multidrug, tetracycline, and β-lactam resistance as the most dominant types. Composting significantly reduced the diversity and relative abundance of ARGs and mobile genetic elements (MGEs) in the cattle manure. In the 120-day microcosm incubation, the diversity and abundance of ARGs in manure-treated soils were significantly higher than those in compost-treated soils at the beginning of the experiment. The level of antibiotic resistance rapidly declined over time in all manure- and compost-treated soils, coupled with similar temporal patterns of manure- and compost-derived bacterial communities as revealed by SourceTracker analysis. The network analysis revealed more intensive interactions/associations among ARGs and MGEs in manure-treated soils than in compost-treated soils, suggesting that mobility potential of ARGs was lower in soils amended with compost. Our results provide evidence that aerobic composting of cattle manure may be an effective approach to mitigate the risk of antibiotic resistance propagation associated with land application of organic wastes. Copyright © 2017 Elsevier B.V. All rights reserved.

Bioremediation and phytoremediation of total petroleum hydrocarbons (TPH) under various conditions.

PubMed

McIntosh, Patrick; Schulthess, Cristian P; Kuzovkina, Yulia A; Guillard, Karl

2017-08-03

Remediation of contaminated soils is often studied using fine-textured soils rather than low-fertility sandy soils, and few studies focus on recontamination events. This study compared aerobic and anaerobic treatments for remediation of freshly introduced used motor oil on a sandy soil previously phytoremediated and bioacclimated (microorganisms already adapted in the soil environment) with some residual total petroleum hydrocarbon (TPH) contamination. Vegetated and unvegetated conditions to remediate anthropogenic fill containing residual TPH that was spiked with nonaqueous phase liquids (NAPLs) were evaluated in a 90-day greenhouse pot study. Vegetated treatments used switchgrass (Panicum virgatum). The concentration of aerobic bacteria were orders of magnitude higher in vegetated treatments compared to unvegetated. Nevertheless, final TPH concentrations were low in all saturated soil treatments, and high in the presence of switchgrass. Concentrations were also low in unvegetated pots with fertilizer. Acclimated indigenous microbial communities were shown to be more effective in breaking down hydrocarbons than introducing microbes from the addition of plant treatments in sandy soils. Remediation of fresh introduced NAPLs on pre-phytoremediated and bioacclimated soil was most efficient in saturated, anaerobic environments, probably due to the already pre-established microbial associations, easily bioavailable contaminants, and optimized soil conditions for microbial establishment and survival.

Why biochar application did not improve the soil water retention of a sandy soil: An investigation into the underlying mechanisms.

NASA Astrophysics Data System (ADS)

Jeffery, Simon; Meinders, Marcel B. J.; Stoof, Cathelijne; Bezemer, T. Martijn; vande Voorde, Tess F. J.; Mommer, Liesje; Willem van Groenigen, Jan

2015-04-01

Biochar application to soil is currently being widely touted as a means to improve soil quality and to enhance the provision of numerous ecosystem services, including water storage, in soils. However, evidence for hydrological effects in the primary literature remain inconclusive with contradictory effects reported. The mechanisms behind such contradictory results are not yet elucidated. As such we aimed to investigate the effects of biochar on soil water retention and infiltration, as well as the underlying mechanisms. To do so we set up two field experiments with biochar produced from herbaceous feedstock through slow pyrolysis at two temperatures (400°C and 600°C). In the first experiment both biochars were applied at a rate of 10 t ha-1 to separate plots in a sandy soil in a North European grassland. In a separate experiment, the biochar produced at 400°C was applied to a different set of plots in the same grassland at rates equivalent to 1, 5, 20 and 50 t ha-1. Soils from these experiments were analysed for soil water retention and infiltration rate as well as aggregate stability and other soil physical parameters. The pore structure of the biochar was fully characterised using X-ray computed micro-tomography (XRT) and hydrophobicity determined using contact angle measurements. There were no significant effects of biochar application on soil water retention, field saturated conductivity or aggregate stability in either experiment. XRT analysis of the biochars confirmed that the biochars were highly porous, with 48% and 57% porosity for the 400°C and 600°C biochars, respectively. More than 99% of internal pores of the biochar particles were connected to the surface, suggesting a potential role for biochars in improving soil water retention. However, the biochars were highly hydrophobic as demonstrated by the high contact angles when water was applied. We suggest that this hydrophobicity greatly diminished water infiltration into the biochar particles

[Dynamic changes of surface soil organic carbon and light-fraction organic carbon after mobile dune afforestation with Mongolian pine in Horqin Sandy Land].

PubMed

Shang, Wen; Li, Yu-qiang; Wang, Shao-kun; Feng, Jing; Su, Na

2011-08-01

This paper studied the dynamic changes of surface (0-15 cm) soil organic carbon (SOC) and light-fraction organic carbon (LFOC) in 25- and 35-year-old sand-fixing Mongolian pine (Pinus sylvestris var. mongolica) plantations in Horqin Sandy Land, with a mobile dune as a comparison site. After the afforestation on mobile dune, the content of coarse sand in soil decreased, while that of fine sand and clay-silt increased significantly. The SOC and LFOC contents also increased significantly, but tended to decrease with increasing soil depth. Afforestation increased the storages of SOC and LFOC in surface soil, and the increment increased with plantation age. In the two plantations, the increment of surface soil LFOC storage was much higher than that of SOC storage, suggesting that mobile dune afforestation had a larger effect on surface soil LFOC than on SOC.

Proposal of new convenient extractant for assessing phytoavailability of heavy metals in contaminated sandy soil.

PubMed

Korzeniowska, Jolanta; Stanislawska-Glubiak, Ewa

2017-06-01

The aim of the study was to compare the usefulness of 1 M HCl with aqua regia, EDTA, and CaCl 2 for the extraction of phytoavailable forms of Cu, Ni, and Zn on coarse-textured soils contaminated with these metals. Two microplot experiments were used for the studies. Reed canary grass (Phalaris arundinacea), maize (Zea mays), willow (Salix viminalis), spartina (Spartina pectinata), and miscanthus (Miscanthus × giganteus) were used as test plants. They were grown on soil artificially spiked with Cu, Ni, and Zn. The experimental design included a control and three increasing doses of metals. Microplots (1 m 2  × 1 m deep) were filled with sandy soil (clay-6%, pH 5.5, Corg-0.8%). Metals in the form of sulfates were dissolved in water and applied to the plot using a hand liquid sprayer. During the harvest, samples were collected from aboveground parts, roots, and the soil and then tested for their Cu, Zn, and Ni contents. The metal content of the soil was determined using four tested extractants. It was found that Cu and Ni were accumulated in roots in bigger amounts than Zn. The usefulness of the extractants was evaluated based on the correlation between the content of metals in the soil and the plant (n = 32). This study demonstrated that 1 M HCl, aqua regia, and EDTA were more efficient or equally useful for the assessment of the phytoavailability of Cu, Ni, and Zn as CaCl 2 . Due to the ease of performing determinations and their low cost, 1 M HCl can be recommended to assess the excess of Cu, Ni, and Zn in the coarse-textured soils.

Spatial distribution of hydroxylamine and its role in aerobic N2O formation in a Norway spruce forest soil

NASA Astrophysics Data System (ADS)

Liu, S.; Weymann, D.; Gottselig, N.; Wiekenkamp, I.; Vereecken, H.; Brueggemann, N.

2014-12-01

Hydroxylamine (HA) as a crucial intermediate in the microbial oxidation of ammonium to nitrite (nitrification) is a potential precursor of abiotic N2O formation in the soil. However, the determination of HA concentration in natural soil samples has not been reported until now. Here, we determined the HA concentrations in organic (Oh) and mineral (Ah) layers of 135 soil samples collected from a spruce forest (Wüstebach, Eifel National Park, Germany) using a novel approach, based on the fast extraction of HA from the soil at a pH of 1.7, the oxidation of HA to N2O with Fe3+, and the analysis of produced N2O using gas chromatography (GC). Meanwhile, N2O emission rates were determined by means of aerobic laboratory incubations of 3-g soil in 22-mL vials. Subsequently, the spatial distribution of soil HA concentrations and N2O emission rates in the Oh and Ah layers of the whole sampling area were analyzed using a geostatistical approach. The correlations among soil HA, N2O emission rate, pH, soil C, N, Fe, Mn and soil water content (SWC) were further explored. The HA concentrations ranged from 0.3-44.6 μg N kg-1 dry soil and 0.02-16.2 μg N kg-1 dry soil in the Oh and the Ah layer, respectively. The spatial distribution of HA was similar in both layers, with substantial spatial variability dependent on soil type, tree density and distance to a stream. For example, HA concentration was greater at locations with a thick litter layer or at locations close to the stream. The average N2O emission rate in the Oh layer was 0.38 μg N kg-1 dry soil h-1, 10-fold larger than in the Ah layer. Interestingly, N2O emission rate exhibited high correlation with soil HA content in the Oh (R2 = 0.65, p < 0.01) and Ah (R2 = 0.45, p < 0.05) layer. The results demonstrated that HA is a crucial component for aerobic N2O formation and emission in spruce forest soils. Moreover, HA concentration was negatively correlated with pH and positively correlated with SWC in the Oh layer, while

Seasonal Dynamics of Water Use Strategy of Two Salix Shrubs in Alpine Sandy Land, Tibetan Plateau.

PubMed

Zhu, Yajuan; Wang, Guojie; Li, Renqiang

2016-01-01

Water is a limiting factor for plant growth and vegetation dynamics in alpine sandy land of the Tibetan Plateau, especially with the increasing frequency of extreme precipitation events and drought caused by climate change. Therefore, a relatively stable water source from either deeper soil profiles or ground water is necessary for plant growth. Understanding the water use strategy of dominant species in the alpine sandy land ecosystem is important for vegetative rehabilitation and ecological restoration. The stable isotope methodology of δD, δ18O, and δ13C was used to determine main water source and long-term water use efficiency of Salix psammophila and S. cheilophila, two dominant shrubs on interdune of alpine sandy land in northeastern Tibetan Plateau. The root systems of two Salix shrubs were investigated to determine their distribution pattern. The results showed that S. psammophila and S. cheilophila absorbed soil water at different soil depths or ground water in different seasons, depending on water availability and water use strategy. Salix psammophila used ground water during the growing season and relied on shallow soil water recharged by rain in summer. Salix cheilophila used ground water in spring and summer, but relied on shallow soil water recharged by rain in spring and deep soil water recharged by ground water in fall. The two shrubs had dimorphic root systems, which is coincident with their water use strategy. Higher biomass of fine roots in S. psammophila and longer fine roots in S. cheilophila facilitated to absorb water in deeper soil layers. The long-term water use efficiency of two Salix shrubs increased during the dry season in spring. The long-term water use efficiency was higher in S. psammophila than in S. cheilophila, as the former species is better adapted to semiarid climate of alpine sandy land.

Seasonal Dynamics of Water Use Strategy of Two Salix Shrubs in Alpine Sandy Land, Tibetan Plateau

PubMed Central

Zhu, Yajuan; Wang, Guojie; Li, Renqiang

2016-01-01

Water is a limiting factor for plant growth and vegetation dynamics in alpine sandy land of the Tibetan Plateau, especially with the increasing frequency of extreme precipitation events and drought caused by climate change. Therefore, a relatively stable water source from either deeper soil profiles or ground water is necessary for plant growth. Understanding the water use strategy of dominant species in the alpine sandy land ecosystem is important for vegetative rehabilitation and ecological restoration. The stable isotope methodology of δD, δ18O, and δ13C was used to determine main water source and long-term water use efficiency of Salix psammophila and S. cheilophila, two dominant shrubs on interdune of alpine sandy land in northeastern Tibetan Plateau. The root systems of two Salix shrubs were investigated to determine their distribution pattern. The results showed that S. psammophila and S. cheilophila absorbed soil water at different soil depths or ground water in different seasons, depending on water availability and water use strategy. Salix psammophila used ground water during the growing season and relied on shallow soil water recharged by rain in summer. Salix cheilophila used ground water in spring and summer, but relied on shallow soil water recharged by rain in spring and deep soil water recharged by ground water in fall. The two shrubs had dimorphic root systems, which is coincident with their water use strategy. Higher biomass of fine roots in S. psammophila and longer fine roots in S. cheilophila facilitated to absorb water in deeper soil layers. The long-term water use efficiency of two Salix shrubs increased during the dry season in spring. The long-term water use efficiency was higher in S. psammophila than in S. cheilophila, as the former species is better adapted to semiarid climate of alpine sandy land. PMID:27243772

Community-specific impacts of exotic earthworm invasions on soil carbon dynamics in a sandy temperate forest.

PubMed

Crumsey, Jasmine M; Le Moine, James M; Capowiez, Yvan; Goodsitt, Mitchell M; Larson, Sandra C; Kling, George W; Nadelhoffer, Knute J

2013-12-01

Exotic earthworm introductions can alter above- and belowground properties of temperate forests, but the net impacts on forest soil carbon (C) dynamics are poorly understood. We used a mesocosm experiment to examine the impacts of earthworm species belonging to three different ecological groups (Lumbricus terrestris [anecic], Aporrectodea trapezoides [endogeic], and Eisenia fetida [epigeic]) on C distributions and storage in reconstructed soil profiles from a sandy temperate forest soil by measuring CO2 and dissolved organic carbon (DOC) losses, litter C incorporation into soil, and soil C storage with monospecific and species combinations as treatments. Soil CO2 loss was 30% greater from the Endogeic x Epigeic treatment than from controls (no earthworms) over the first 45 days; CO2 losses from monospecific treatments did not differ from controls. DOC losses were three orders of magnitude lower than CO2 losses, and were similar across earthworm community treatments. Communities with the anecic species accelerated litter C mass loss by 31-39% with differential mass loss of litter types (Acer rubrum > Populus grandidentata > Fagus grandifolia > Quercus rubra > or = Pinus strobus) indicative of leaf litter preference. Burrow system volume, continuity, and size distribution differed across earthworm treatments but did not affect cumulative CO2 or DOC losses. However, burrow system structure controlled vertical C redistribution by mediating the contributions of leaf litter to A-horizon C and N pools, as indicated by strong correlations between (1) subsurface vertical burrows made by anecic species, and accelerated leaf litter mass losses (with the exception of P. strobus); and (2) dense burrow networks in the A-horizon and the C and N properties of these pools. Final soil C storage was slightly lower in earthworm treatments, indicating that increased leaf litter C inputs into soil were more than offset by losses as CO2 and DOC across earthworm community treatments.

Soil color indicates carbon and wetlands: developing a color-proxy for soil organic carbon and wetland boundaries on sandy coastal plains in South Africa.

PubMed

Pretorius, M L; Van Huyssteen, C W; Brown, L R

2017-10-13

A relationship between soil organic carbon and soil color is acknowledged-albeit not a direct one. Since heightened carbon contents can be an indicator of wetlands, a quantifiable relationship between color and carbon might assist in determining wetland boundaries by rapid, field-based appraisal. The overarching aim of this initial study was to determine the potential of top soil color to indicate soil organic carbon, and by extension wetland boundaries, on a sandy coastal plain in South Africa. Data were collected from four wetland types in northern KwaZulu-Natal in South Africa. Soil samples were taken to a depth of 300 mm in three transects in each wetland type and analyzed for soil organic carbon. The matrix color was described using a Munsell soil color chart. Various color indices were correlated with soil organic carbon. The relationship between color and carbon were further elucidated using segmented quantile regression. This showed that potentially maximal carbon contents will occur at values of low color indices, and predictably minimal carbon contents will occur at values of low or high color indices. Threshold values can thus be used to make deductions such as "when the sum of dry and wet Value and Chroma values is 9 or more, carbon content will be 4.79% and less." These threshold values can then be used to differentiate between wetland and non-wetland sites with a 70 to 100% certainty. This study successfully developed a quantifiable correlation between color and carbon and showed that wetland boundaries can be determined based thereon.

Response of N2O emissions to biochar amendment in a cultivated sandy loam soil during freeze-thaw cycles

PubMed Central

Liu, Xiang; Wang, Quan; Qi, Zhiming; Han, Jiangang; Li, Lanhai

2016-01-01

In the last decade, an increasing number of studies have reported that soil nitrous oxide (N2O) emissions can be reduced by adding biochar. However, the effect of biochar amendment on soil N2O emissions during freeze-thaw cycle (FTC) is still unknown. In this laboratory study, biochar (0%, 2% and 4%, w/w) was added into a cultivated sandy loam soil and then treated with 15 times of FTC (each FTC consisted of freeze at −5/−10 °C for 24 h and thaw at 5/10 °C for 24 h), to test whether biochar can mitigate soil N2O emissions during FTC, and estimate the relationships between N2O emissions and soil inorganic nitrogen contents/microbial biomass content/enzyme activities. The results showed that biochar amendment suppressed soil N2O emissions by 19.9–69.9% as compared to soils without biochar amendment during FTC. However, N2O emissions were only significantly correlated to soil nitrate nitrogen (NO3−-N) contents, which decreased after biochar amendment, indicating that the decreased soil nitrification by adding biochar played an important role in mitigating N2O emissions during FTC. Further studies are needed to estimate the effectiveness of biochar amendment on reducing freeze-thaw induced N2O emissions from different soils under field conditions. PMID:27748462

Impact of Rotylenchulus reniformis on Cotton Yield as Affected by Soil Texture and Irrigation

PubMed Central

Herring, Stephanie L.; Heitman, Joshua L.

2010-01-01

The effects of soil type, irrigation, and population density of Rotylenchulus reniformis on cotton were evaluated in a two-year microplot experiment. Six soil types, Fuquay sand, Norfolk sandy loam, Portsmouth loamy sand, Muck, Cecil sandy loam, and Cecil sandy clay, were arranged in randomized complete blocks with five replications. Each block had numerous plots previously inoculated with R. reniformis and two or more noninoculated microplots per soil type, one half of which were irrigated in each replicate for a total of 240 plots. Greatest cotton lint yields were achieved in the Muck, Norfolk sandy loam, and Portsmouth loamy sand soils. Cotton yield in the Portsmouth loamy sand did not differ from the Muck soil which averaged the greatest lint yield per plot of all soil types. Cotton yield was negatively related to R. reniformis PI (initial population density) in all soil types except for the Cecil sandy clay which had the highest clay content. Supplemental irrigation increased yields in the higher yielding Muck, Norfolk sandy loam, and Portsmouth loamy sand soils compared to the lower yielding Cecil sandy clay, Cecil sandy loam, and Fuquay sand soils. The Portsmouth sandy loam was among the highest yielding soils, and also supported the greatest R. reniformis population density. Cotton lint yield was affected more by R. reniformis Pi with irrigation in the Portsmouth loamy sand soil with a greater influence of Pi on lint yield in irrigated plots than other soils. A significant first degree PI × irrigation interaction for this soil type confirms this observation. PMID:22736865

Impact of Rotylenchulus reniformis on Cotton Yield as Affected by Soil Texture and Irrigation.

PubMed

Herring, Stephanie L; Koenning, Stephen R; Heitman, Joshua L

2010-12-01

The effects of soil type, irrigation, and population density of Rotylenchulus reniformis on cotton were evaluated in a two-year microplot experiment. Six soil types, Fuquay sand, Norfolk sandy loam, Portsmouth loamy sand, Muck, Cecil sandy loam, and Cecil sandy clay, were arranged in randomized complete blocks with five replications. Each block had numerous plots previously inoculated with R. reniformis and two or more noninoculated microplots per soil type, one half of which were irrigated in each replicate for a total of 240 plots. Greatest cotton lint yields were achieved in the Muck, Norfolk sandy loam, and Portsmouth loamy sand soils. Cotton yield in the Portsmouth loamy sand did not differ from the Muck soil which averaged the greatest lint yield per plot of all soil types. Cotton yield was negatively related to R. reniformis PI (initial population density) in all soil types except for the Cecil sandy clay which had the highest clay content. Supplemental irrigation increased yields in the higher yielding Muck, Norfolk sandy loam, and Portsmouth loamy sand soils compared to the lower yielding Cecil sandy clay, Cecil sandy loam, and Fuquay sand soils. The Portsmouth sandy loam was among the highest yielding soils, and also supported the greatest R. reniformis population density. Cotton lint yield was affected more by R. reniformis Pi with irrigation in the Portsmouth loamy sand soil with a greater influence of Pi on lint yield in irrigated plots than other soils. A significant first degree PI × irrigation interaction for this soil type confirms this observation.

Effects of organic fertilizers and biochar/organic fertilizer combinations on fertility and organic matter dynamics of a sandy soil in north-west Germany

NASA Astrophysics Data System (ADS)

Greenberg, Isabel; Kaiser, Michael; Polifka, Steven; Wiedner, Katja; Glaser, Bruno; Ludwig, Bernard

2017-04-01

Biochar and biochar/organic fertilizer combinations have been recommended as soil amendments to improve plant productivity and soil properties, as well as to increase soil organic C (OC) storage. However, these claims have been largely unverified by field experiments lasting several years. To address these issues, a field experiment was established in 2012 to analyze the effects of organic fertilizers and biochar/organic fertilizer combinations (five field replicates, fully randomized block design) on the fertility and organic matter dynamics of a sandy Cambisol. In 2016, samples were taken from the 0-10 cm and 10-30 cm soil depths of the following treatments: mineral fertilizer and maize digestate that were applied both individually and in combination with 1 t/ha or 40 t/ha biochar. Further treatments were compost and 10 t/ha composted biochar. The treatments were analyzed for the plant yield and the bulk soil samples were analyzed for the pH, cation exchange capacity (CEC), OC content, microbial biomass C and the distribution of aggregate-size fractions (i.e. >2 mm, 2 mm - 250 µm, 250 - 53 µm, <53 µm). The latter were also analyzed for OC content and by FTIR. In 2012, the combination of 40 t/ha biochar+digestate accounted for about 42% higher maize (Zea mays) yields (7.9 t/ha) than the mineral fertilization treatment. For winter rye (Secale cereale) in 2013, we detected the highest yield (10.4 t/ha) for the 10 t/ha composted biochar treatment. In 2014, the highest yield for blue lupine (Lupinus angustifolius) (1.84 t/ha) was detected for the 40 t/ha biochar+digestate treatment. The first data for the soil samples indicate that the 10 t/ha composted biochar and the compost treatment are most effective in increasing the CEC, and the microbial biomass C content of the soil, while pH was not significantly affected by any of the treatments. The bulk soil OC content of the treatments receiving 40 t/ha biochar+fertilizer (digestate or mineral), 10 t/ha composted

Crop water use efficiency following biochar application on maize cropping systems on sandy soils of tropical semiarid eastern Indonesia

NASA Astrophysics Data System (ADS)

Sukartono, S.; Utomo, W.

2012-04-01

A field study was conducted to evaluate the effect of biochar on crop water use efficiency under three consecutive maize cropping system on sandy loam of Lombok, eastern Indonesia from December 2010 to October 2011.The treatments tested were: coconut shell- biochar (CSB), cattle dung-biochar (CDB), cattle manure applied at only early first crop (CM1) and cattle manure applied at every planting time (CM2) and no organic amendment as the control. Evaluation after the end of third maize, the application of organic amendments (biochar and cattle manure) slightly altered the pore size distribution resulting changes in water retention and the available water capacity. The available water capacity was relatively comparable between biochar treated soils (0.206 cm3 cm-3) and soil treated with cattle manure applied at every planting time (0.220 cm3 cm-3). Water use efficiency (WUE) of maize under biochars were 9.44 kg/mm (CSB) and 9.24 kg/mm (CDB) while WUE for CM1 and CM2 were 8.54 and 9.97 kg/mm respectively, and control was 8.08 kg/mm. Thus, biochars as well as cattle manure applied at every planting time improved water use efficiency by 16.83% and 23.39 respectively compared to control. Overall, this study confirms that biochar and cattle manure are both valuable amendments for improving water use efficiency and to sustain maize production in the sandy loam soils of semiarid North Lombok, eastern Indonesia. However, unlike bicohar, in order to maintain its posivtive effect, cattle manure should be applied at every planting time, and this make cattle manure application is more costly. Keywords: Biochar, organic management, catle manure, water retention, maize yield

A genetic-algorithm approach for assessing the liquefaction potential of sandy soils

NASA Astrophysics Data System (ADS)

Sen, G.; Akyol, E.

2010-04-01

The determination of liquefaction potential is required to take into account a large number of parameters, which creates a complex nonlinear structure of the liquefaction phenomenon. The conventional methods rely on simple statistical and empirical relations or charts. However, they cannot characterise these complexities. Genetic algorithms are suited to solve these types of problems. A genetic algorithm-based model has been developed to determine the liquefaction potential by confirming Cone Penetration Test datasets derived from case studies of sandy soils. Software has been developed that uses genetic algorithms for the parameter selection and assessment of liquefaction potential. Then several estimation functions for the assessment of a Liquefaction Index have been generated from the dataset. The generated Liquefaction Index estimation functions were evaluated by assessing the training and test data. The suggested formulation estimates the liquefaction occurrence with significant accuracy. Besides, the parametric study on the liquefaction index curves shows a good relation with the physical behaviour. The total number of misestimated cases was only 7.8% for the proposed method, which is quite low when compared to another commonly used method.

Mobility and dissipation of chlorpyriphos and quinalphos in sandy clay loam in an agroecosystem-a laboratory-based soil column study.

PubMed

G P, Bindumol; C C, Harilal

2017-09-15

Leaching potential of pesticides, apart from climatological factors, depends on soil physical properties, soil-pesticide interaction and chemical nature of the molecule. Recent investigations have revealed the presence of various organophosphate pesticides in various agroecosystems. The present study investigated the soil transport mechanism of commonly used organophosphate pesticides in acidic sandy clay loam soils of Kerala State, India. Packed soil column experiment was undertaken under laboratory condition for 30 days. Unsaturated flow was carried out using distilled water/0.01 M CaCl 2 solution after applying chlorpyriphos and quinalphos at the rate of 0.04% a.i.ha -1 and 0.025% a.i.ha -1 , respectively. The study revealed the retention of residues of chlorpyriphos and quinalphos in the top 5-cm layer. Irrespective of the applied concentration of chlorpyriphos and quinalphos, the relative concentration of the pesticides in soil was similar. About 56% of the applied chemicals were dissipated in 30 days of unsaturated flow. A new dissipation compound iron, tricarbonyl [N-(phenyl-2-pyridinylmethyene) benzenamine-N, N'], was detected in GCMS analysis of soil extract from distilled water percolated soil. The dissipation of chlorpyriphos and quinalphos was faster in 0.01 M CaCl 2 -treated soil column. Among the pesticides analysed, the residue of quinalphos was detected in leachate.

Copper Accumulation, Availability and Adsorption Capacity in Sandy Soils of Vineyards with Different Cultivation Duration

NASA Astrophysics Data System (ADS)

Mallmann, F. J. K.; Miotto, A.; Bender, M. A.; Gubiani, E.; Rheinheimer, D. D. S.; Kaminski, J.; Ceretta, C. A.; Šimůnek, J.

2015-12-01

Bordeaux mixture is a copper-based (Cu) fungicide and bactericide applied in vineyards to control plant diseases. Since it is applied several times per year, it accumulates in large quantities on plants and in soil. This study evaluates the Cu accumulation in, and desorption kinetics and adsorption capability of a sandy Ultisol in a natural field and in 3 vineyards for 5 (V1), 11 (V2), and 31 (V3) years in South of Brazil. Soil samples were collected in 8 depths (0-60 cm) of all four soil profiles, which all displayed similar soil properties. The following soil properties were measured: pH, organic matter (OM), soil bulk density, Cu total concentration, and Cu desorption and adsorption curves. A two first-order reactions model and the Langmuir isotherm were fitted to the desorption and adsorption curves, respectively. An increase in the total mass of Cu in the vineyards followed a linear regression curve, with an average annual increase of 7.15 kg ha-1. Cu accumulated down to a depth of 5, 20, and 30 cm in V1, V2 and V3, respectively, with the highest Cu content reaching 138.4 mg kg-1 in the 0-5 cm soil layer of V3. Cu desorption parameters showed a high correlation with its total concentration. Approximately 57 and 19% of total Cu were immediately and slowly available, respectively, indicating a high potential for plant absorption and/or downward movement. Cu concentrations extracted by EDTA from soil layers not affected by anthropogenic Cu inputs were very low. The maximum Cu adsorption capacity of the 0-5 and 5-10 cm soil layers increased with the vineyard age, reaching concentrations higher than 900 mg kg-1. This increase was highly related to OM and pH, which both increased with cultivation duration. Despite of low clay content of these soils, there is low risk of groundwater Cu contamination for actual conditions. However, high Cu concentrations in the surface layer of the long-term vineyards could cause toxicity problems for this and for companion crops.

Interaction of aerobic soil bacteria with plutonium(VI)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Panak, Petra J.; Nitsche, Heino

2000-08-22

We studied the interaction of Pu(VI) with Pseudomonas stutzeri ATCC 17588 and Bacillus sphaericus ATCC 14577, representatives of the main aerobic groups of soil bacteria present in the upper soil layers. The accumulation studies have shown that these soil bacteria accumulate high amounts of Pu(VI). The sorption efficiency toward Pu(VI) decreased with increasing biomass concentration due to increased agglomeration of the bacteria resulting in a decreased total surface area and number of available complexing groups. Spores of Bacillus sphaericus showed a higher biosorption than the vegetative cells at low biomass concentration which decreased significantly with increasing biomass concentration. At highermore » biomass concentrations (> 0.7 g/L), the vegetative cells of both strains and the spores of B. sphaericus showed comparable sorption efficiencies. Investigations on the pH dependency of the biosorption and extraction studies with 0.01 M EDTA solution have shown that the biosorption of plutonium is a reversible process and the plutonium is bound by surface complexation. Optical absorption spectroscopy showed that one third of the initially present Pu(VI) was reduced to Pu(V) after 24 hours. Kinetic studies and solvent extraction to separate different oxidation states of Pu after contact with the biomass provided further information on the yield and the kinetics of the bacteria-mediated reduction. Long-term studies showed that also 16% of Pu(IV) was formed after one month. The comparison of the amount of Pu(IV) formed during that time period with literature data of the Pu(V) disproportionation, indicated that the Pu(IV) seemed to be rather the result of the disproportionation of the formed Pu(V) than of a further microbial reduction.« less

Jatropha curcas L. Root Structure and Growth in Diverse Soils

PubMed Central

Valdés-Rodríguez, Ofelia Andrea; Sánchez-Sánchez, Odilón; Pérez-Vázquez, Arturo; Caplan, Joshua S.; Danjon, Frédéric

2013-01-01

Unlike most biofuel species, Jatropha curcas has promise for use in marginal lands, but it may serve an additional role by stabilizing soils. We evaluated the growth and structural responsiveness of young J. curcas plants to diverse soil conditions. Soils included a sand, a sandy-loam, and a clay-loam from eastern Mexico. Growth and structural parameters were analyzed for shoots and roots, although the focus was the plasticity of the primary root system architecture (the taproot and four lateral roots). The sandy soil reduced the growth of both shoot and root systems significantly more than sandy-loam or clay-loam soils; there was particularly high plasticity in root and shoot thickness, as well as shoot length. However, the architecture of the primary root system did not vary with soil type; the departure of the primary root system from an index of perfect symmetry was 14 ± 5% (mean ± standard deviation). Although J. curcas developed more extensively in the sandy-loam and clay-loam soils than in sandy soil, it maintained a consistent root to shoot ratio and root system architecture across all types of soil. This strong genetic determination would make the species useful for soil stabilization purposes, even while being cultivated primarily for seed oil. PMID:23844412

Jatropha curcas L. root structure and growth in diverse soils.

PubMed

Valdés-Rodríguez, Ofelia Andrea; Sánchez-Sánchez, Odilón; Pérez-Vázquez, Arturo; Caplan, Joshua S; Danjon, Frédéric

2013-01-01

Unlike most biofuel species, Jatropha curcas has promise for use in marginal lands, but it may serve an additional role by stabilizing soils. We evaluated the growth and structural responsiveness of young J. curcas plants to diverse soil conditions. Soils included a sand, a sandy-loam, and a clay-loam from eastern Mexico. Growth and structural parameters were analyzed for shoots and roots, although the focus was the plasticity of the primary root system architecture (the taproot and four lateral roots). The sandy soil reduced the growth of both shoot and root systems significantly more than sandy-loam or clay-loam soils; there was particularly high plasticity in root and shoot thickness, as well as shoot length. However, the architecture of the primary root system did not vary with soil type; the departure of the primary root system from an index of perfect symmetry was 14 ± 5% (mean ± standard deviation). Although J. curcas developed more extensively in the sandy-loam and clay-loam soils than in sandy soil, it maintained a consistent root to shoot ratio and root system architecture across all types of soil. This strong genetic determination would make the species useful for soil stabilization purposes, even while being cultivated primarily for seed oil.

Effect of moisture and compost on fate of azoxystrobin in soils.

PubMed

Singh, Neera; Singh, Shashi B

2010-10-01

The effect of compost-amendment and moisture status on the persistence of azoxystrobin [methyl (E)-2-{2-(6-(2-cyanophenoxy) pyrimidin-4-yloxy) phenyl}-3-methoxyacrylate], a strobilurin fungicide, in two rice-growing soils was studied. Azoxystrobin is more sorbed in the silt loam (K f – 4.66) soil than the sandy loam (K f – 2.98) soil. Compost-amendment at 5 % levels further enhanced the azoxystrobin sorption and the respective Kf values in silt loam and sandy loam soils were 8.48 and 7.6. Azoxystrobin was more persistent in the sandy loam soil than the silt loam soil. The half–life values of azoxystrobin in nonflooded and flooded silt loam soil were 54.7 and 46.3 days, respectively. The corresponding half–life values in the sandy loam soils were 64 and 62.7 days, respectively. Compost application enhanced persistence of azoxystrobin in the silt loam soil under both moisture regimes and half-life values in non–flooded and flooded soils were 115.7 and 52.8 days, respectively. However, compost enhanced azoxystrobin degradation in the sandy loam soil and half-life values were 59 (nonflooded) and 54.7 days (flooded). The study indicates that compost amendment enhanced azoxystrobin sorption in the soils. Azoxystrobin is more persistent in non-flooded soils than the flooded soils. Compost applications to soils had mixed effect on the azoxystrobin degradation.

Dissolved organic matter removal during coal slag additive soil aquifer treatment for secondary effluent recharging: Contribution of aerobic biodegradation.

PubMed

Wei, Liangliang; Li, Siliang; Noguera, Daniel R; Qin, Kena; Jiang, Junqiu; Zhao, Qingliang; Kong, Xiangjuan; Cui, Fuyi

2015-06-01

Recycling wastewater treatment plant (WWTP) effluent at low cost via the soil aquifer treatment (SAT), which has been considered as a renewable approach in regenerating potable and non-potable water, is welcome in arid and semi-arid regions throughout the world. In this study, the effect of a coal slag additive on the bulk removal of the dissolved organic matter (DOM) in WWTP effluent during SAT operation was explored via the matrix configurations of both coal slag layer and natural soil layer. Azide inhibition and XAD-resins fractionation experiments indicated that the appropriate configuration designing of an upper soil layer (25 cm) and a mixture of soil/coal slag underneath would enhance the removal efficiency of adsorption and anaerobic biodegradation to the same level as that of aerobic biodegradation (31.7% vs 32.2%), while it was only 29.4% compared with the aerobic biodegradation during traditional 50 cm soil column operation. The added coal slag would preferentially adsorb the hydrophobic DOM, and those adsorbed organics could be partially biodegraded by the biomass within the SAT systems. Compared with the relatively lower dissolved organic carbon (DOC), ultraviolet light adsorption at 254 nm (UV-254) and trihalomethane formation potential (THMFP) removal rate of the original soil column (42.0%, 32.9%, and 28.0%, respectively), SSL2 and SSL4 columns would enhance the bulk removal efficiency to more than 60%. Moreover, a coal slag additive in the SAT columns could decline the aromatic components (fulvic-like organics and tryptophan-like proteins) significantly. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of aerobic and anaerobic biological processes on leaching of heavy metals from soil amended with sewage sludge compost.

PubMed

Fang, Wen; Wei, Yonghong; Liu, Jianguo; Kosson, David S; van der Sloot, Hans A; Zhang, Peng

2016-12-01

The risk from leaching of heavy metals is a major factor hindering land application of sewage sludge compost (SSC). Understanding the change in heavy metal leaching resulting from soil biological processes provides important information for assessing long-term behavior of heavy metals in the compost amended soil. In this paper, 180days aerobic incubation and 240days anaerobic incubation were conducted to investigate the effects of the aerobic and anaerobic biological processes on heavy metal leaching from soil amended with SSC, combined with chemical speciation modeling. Results showed that leaching concentrations of heavy metals at natural pH were similar before and after biological process. However, the major processes controlling heavy metals were influenced by the decrease of DOC with organic matter mineralization during biological processes. Mineralization of organic matter lowered the contribution of DOC-complexation to Ni and Zn leaching. Besides, the reducing condition produced by biological processes, particularly by the anaerobic biological process, resulted in the loss of sorption sites for As on Fe hydroxide, which increased the potential risk of As release at alkaline pH. Copyright © 2016 Elsevier Ltd. All rights reserved.

Application of N-modified lignite and activated biochar to increase growth of summer wheat on nutrient-poor sandy soil

NASA Astrophysics Data System (ADS)

Schillem, Steffi; Schneider, Bernd-Uwe; Zeihser, Uwe; Hüttl, Reinhard F.

2017-04-01

Land degradation is recognized as the main environmental problem that adversely depletes soil organic carbon (SOC) and nitrogen (SON) stocks, which in turn directly affects the fertility and productivity of soils. Degraded soils and marginal lands are characterized by low fertility, poor physicochemical and biological properties and are almost free of soil organic matter (SOM), limiting their functional properties and, hence, their productivity. To enhance or restore the fertility of these soils, natural soil amendments such as biochar, lignite or humic acids can be added. A greenhouse experiment was carried out to investigate the effect of different application rates (5, 7.5, 11, 15, 28 t ha-1) of N-modified lignite (NL) incorporated in a nutrient-poor sandy soil from a recultivation site on plant growth, water use and nitrogen use efficiency of summer wheat. Additionally activated biochar (BC) was tested to see whether any differences exist between N-modified lignite and activated biochar at the same C-application rates. All variants with soil amendments displayed a much higher grain and straw yield and water use efficiency compared to the control sample. The differences were significant for the 28 t ha-1variant followed by the variant with 5 t ha-1 NL. With the 7.5 t ha-1 NL higher biomasses, water and nitrogen use efficiency could be achieved compared to the variant treated with BC at the same C-content. This study shows that even small amounts of N-modified lignite can increase growth, water and nitrogen use efficiency of summer wheat on marginal lands.

Development and survival of Anopheles gambiae eggs in drying soil: influence of the rate of drying, egg age, and soil type.

PubMed

Shililu, J I; Grueber, W B; Mbogo, C M; Githure, J I; Riddiford, L M; Beier, J C

2004-09-01

Little is known about the contribution made by the egg stage of African malaria vectors to the rapid rise in adult populations following the onset of seasonal rains. To examine this issue, we evaluated the viability of Anopheles gambiae eggs in drying soil in the laboratory. Survival data were collected from field-caught mosquitoes kept in sandy loam soil and laboratory-reared colonies kept in sandy loam soil and black cotton soil. Under high, medium, and low soil-moisture regimes, egg viability declined sharply with increased duration of drying. Eggs remained viable in drying sandy loam soil for 1, 5, and 10 days, but not after 15 or 20 days. The most dramatic decline in hatching success occurred between drying days 1 (78-83% hatch) and 5 (20-23% hatch). In contrast, eggs reared in high-moisture black cotton soil remained viable for up to 15 days. Furthermore, after 5 drying days, high-, medium-, and low-moisture soils averaged 59, 47, and 31% hatching success, respectively. We recovered unhatched eggs from sandy loam soils to examine the developmental status of the embryos. A majority of the unhatched eggs that were recovered from days 15 and 20 in sandy loam soils contained fully developed late-stage embryos. Thus, unhatched eggs completed embryonic development but probably died before receiving an appropriate hatching stimulus. Our results suggest that the absolute moisture content of the soil does not alone determine hatching success of anopheline eggs. Rather, soil moisture, together with the rate of drying, physiological factors associated with the age of the egg, and the type of soil in which the egg rests likely influence survival.

Hydraulic conductivity of a sandy soil at low water content after compaction by various methods

USGS Publications Warehouse

Nimmo, John R.; Akstin, Katherine C.

1988-01-01

To investigate the degree to which compaction of a sandy soil influences its unsaturated hydraulic conductivity K, samples of Oakley sand (now in the Delhi series; mixed, thermic, Typic Xeropsamments) were packed to various densities and K was measured by the steady-state centrifuge method. The air-dry, machine packing was followed by centrifugal compression with the soil wet to about one-third saturation. Variations in (i) the impact frequency and (ii) the impact force during packing, and (iii) the amount of centrifugal force applied after packing, produced a range of porosity from 0.333 to 0.380. With volumetric water content θ between 0.06 and 0.12, K values were between 7 × 10−11 and 2 × 10−8 m/s. Comparisons of K at a single θ value for samples differing in porosity by about 3% showed as much as fivefold variation for samples prepared by different packing procedures, while there generally was negligible variation (within experimental error of 8%) where the porosity difference resulted from a difference in centrifugal force. Analysis involving capillary-theory models suggests that the differences in K can be related to differences in pore-space geometry inferred from water retention curves measured for the various samples.

Seasonal variations measured by TDR and GPR on an anthropogenic sandy soil and the implications for utility detection

NASA Astrophysics Data System (ADS)

Curioni, Giulio; Chapman, David N.; Metje, Nicole

2017-06-01

The electromagnetic (EM) soil properties are dynamic variables that can change considerably over time, and they fundamentally affect the performance of Ground Penetrating Radar (GPR). However, long-term field studies are remarkably rare and records of the EM soil properties and their seasonal variation are largely absent from the literature. This research explores the extent of the seasonal variation of the apparent permittivity (Ka) and bulk electrical conductivity (BEC) measured by Time Domain Reflectometry (TDR) and their impact on GPR results, with a particularly important application to utility detection. A bespoke TDR field monitoring station was specifically developed and installed in an anthropogenic sandy soil in the UK for 22 months. The relationship between the temporal variation of the EM soil properties and GPR performance has been qualitatively assessed, highlighting notably degradation of the GPR images during wet periods and a few days after significant rainfall events following dry periods. Significantly, it was shown that by assuming arbitrary average values (i.e. not extreme values) of Ka and BEC which do not often reflect the typical conditions of the soil, it can lead to significant inaccuracies in the estimation of the depth of buried targets, with errors potentially up to approximately 30% even over a depth of 0.50 m (where GPR is expected to be most accurate). It is therefore recommended to measure or assess the soil conditions during GPR surveys, and if this is not possible to use typical wet and dry Ka values reported in the literature for the soil expected at the site, to improve confidence in estimations of target depths.

Deep Soil Recharge in Arid and Semi-Arid Regions: New Evidences in MU-US Sandy Land of China

NASA Astrophysics Data System (ADS)

Cheng, Y.; Yang, W.; Zhan, H.

2017-12-01

Precipitation induced recharge is an important source of groundwater budget but it is very difficult to quantify in arid and semiarid regions. In this study, a newly invented lysimeter was used to monitor deep soil recharge (DSR) under 200 cm depth in MU-US sandy land in western China under three kinds of landforms (mobile dune, semi-fixed dune, and fixed dune). We found that the annual DSRs in such three different kinds of landforms varied significantly. Specifically, the annual DSRs were 224.1 mm (50.5% of the annual precipitation), 71.1 mm (50.5% of the annual precipitation), and 1.3 mm (0.3% of the annual precipitation) in mobile dune, semi-fixed dune, and fixed dune, respectively. We also found that vegetation coverage and precipitation pattern significantly affected DSR. A 24-hr precipitation event with the precipitation amount greater than 8 mm was able to infiltrate soil deeper than 200 cm and contributed to ground water recharge directly. Vegetation was a dominant factor influencing infiltration in the fixed sand dune. Our research revealed that precipitation induced DSR in arid and semi-arid regions was a complex process that required long-term monitoring and innovative system analysis of interrelated factors such as precipitation strength and pattern, meteorological parameters, and dynamic soil moisture. Key words: Precipitation pattern, sand dune groundwater, deep soil recharge, infiltration.

Growth patterns of red pine on fine-textured soils.

Treesearch

David H. Alban; Donald H. Prettyman; Gary J. Brand

1987-01-01

Compares growth of 28- to 49-year-old red pine plantations on sandy and fine-textured soils. Red pine growing on these two contrasting soils did not differ in bole form, live crown ratio, or mortality, and tree growth predicted by models (STEMS and REDPINE) developed from trees growing on sandy soils worked equally well for trees growing on fine-textured soils.

Passive Microwave Observation of Soil Water Infiltration

NASA Technical Reports Server (NTRS)

Jackson, Thomas J.; Schmugge, Thomas J.; Rawls, Walter J.; ONeill, Peggy E.; Parlange, Marc B.

1997-01-01

Infiltration is a time varying process of water entry into soil. Experiments were conducted here using truck based microwave radiometers to observe small plots during and following sprinkler irrigation. Experiments were conducted on a sandy loam soil in 1994 and a silt loam in 1995. Sandy loam soils typically have higher infiltration capabilities than clays. For the sandy loam the observed brightness temperature (TB) quickly reached a nominally constant value during irrigation. When the irrigation was stopped the TB began to increase as drainage took place. The irrigation rates in 1995 with the silt loam soil exceeded the saturated conductivity of the soil. During irrigation the TB values exhibited a pattern that suggests the occurrence of coherent reflection, a rarely observed phenomena under natural conditions. These results suggested the existence of a sharp dielectric boundary (wet over dry soil) that was increasing in depth with time.

Evaluation of Diuron Tolerance and Biotransformation by Fungi from a Sugar Cane Plantation Sandy-Loam Soil.

PubMed

Perissini-Lopes, Bruna; Egea, Tássia Chiachio; Monteiro, Diego Alves; Vici, Ana Cláudia; Da Silva, Danilo Grünig Humberto; Lisboa, Daniela Correa de Oliveira; de Almeida, Eduardo Alves; Parsons, John Robert; Da Silva, Roberto; Gomes, Eleni

2016-12-14

Microorganisms capable of degrading herbicides are essential to minimize the amount of chemical compounds that may leach into other environments. This work aimed to study the potential of sandy-loam soil fungi to tolerate the herbicide Herburon (50% diuron) and to degrade the active ingredient diuron. Verticillium sp. F04, Trichoderma virens F28, and Cunninghamella elegans B06 showed the highest growth in the presence of the herbicide. The evaluation of biotransformation showed that Aspergillus brasiliensis G08, Aspergillus sp. G25, and Cunninghamella elegans B06 had the greatest potential to degrade diuron. Statistical analysis demonstrated that glucose positively influences the potential of the microorganism to degrade diuron, indicating a cometabolic process. Due to metabolites founded by diuron biotransformation, it is indicated that the fungi are relevant in reducing the herbicide concentration in runoff, minimizing the environmental impact on surrounding ecosystems.

An assessment of the effectiveness and impact of electrokinetic remediation for pyrene-contaminated soil.

PubMed

Xu, Sujuan; Guo, Shuhai; Wu, Bo; Li, Fengmei; Li, Tingting

2014-11-01

The effectiveness of electrokinetic remediation for pyrene-contaminated soil was investigated by an anode-cathode separated system using a salt bridge. The applied constant voltage was 24 V and the electrode gap was 24 cm. Two types of soil (sandy soil and loam soil) were selected because of their different conductive capabilities. The initial concentrations of pyrene in these soil samples were 261.3mg/kg sandy soil and 259.8 mg/kg loam soil. After treatment of the sandy soil and loam soil for seven days, 56.8% and 20.1% of the pyrene had been removed respectively. Under the same power supply voltage, the removal of the pollutant from the sandy soil was greater than that from the loam soil, due to the higher current and lower pH. Further analysis revealed that the effectiveness of electrokinetic remediation was affected by the energy expenditure, and was associated with changes in soil properties. Copyright © 2014. Published by Elsevier B.V.

Electrokinetic transport of aerobic microorganisms under low-strength electric fields.

PubMed

Maillacheruvu, Krishnanand Y; Chinchoud, Preethi R

2011-01-01

To investigate the feasibility of utilizing low strength electric fields to transport commonly available mixed cultures such as those from an activated sludge process, bench scale batch reactor studies were conducted in sand and sandy loam soils. A readily biodegradable substrate, dextrose, was used to test the activity of the transported microorganisms. Electric field strengths of 7V, 10.5V, and 14V were used. Results from this investigation showed that an electric field strength of 0.46 Volts per cm was sufficient to transport activated sludge microorganisms across a sandy loam soil across a distance of about 8 cm in 72 h. More importantly, the electrokinetically transported microbial culture remained active and viable after the transport process and was biodegrade 44% of the dextrose in the soil medium. Electrokinetic treatment without microorganisms resulted in removal of 37% and the absence of any treatment yielded a removal of about 15%.

Nitrogen Amendment Stimulated Decomposition of Maize Straw-Derived Biochar in a Sandy Loam Soil: A Short-Term Study.

PubMed

Lu, Weiwei; Ding, Weixin; Zhang, Junhua; Zhang, Huanjun; Luo, Jiafa; Bolan, Nanthi

2015-01-01

This study examined the effect of nitrogen (N) on biochar stability in relation to soil microbial community as well as biochar labile components using δ13C stable isotope technology. A sandy loam soil under a long-term rotation of C3 crops was amended with biochar produced from maize (a C4 plant) straw in absence (BC0) and presence (BCN) of N and monitored for dynamics of carbon dioxide (CO2) flux, phospholipid fatty acids (PLFAs) profile and dissolved organic carbon (DOC) content. N amendment significantly increased the decomposition of biochar during the first 5 days of incubation (P < 0.05), and the proportions of decomposed biochar carbon (C) were 2.30% and 3.28% in BC0 and BCN treatments, respectively, during 30 days of incubation. The magnitude of decomposed biochar C was significantly (P < 0.05) higher than DOC in biochar (1.75%) and part of relatively recalcitrant biochar C was mineralized in both treatments. N amendment increased soil PLFAs concentration at the beginning of incubation, indicating that microorganisms were N-limited in test soil. Furthermore, N amendment significantly (P < 0.05) increased the proportion of gram-positive (G+) bacteria and decreased that of fungi, while no noticeable changes were observed for gram-negative (G-) bacteria and actinobacteria at the early stage of incubation. Our results indicated that N amendment promoted more efficiently the proliferation of G+ bacteria and accelerated the decomposition of relatively recalcitrant biochar C, which in turn reduced the stability of maize straw-derived biochar in test soil.

Nitrogen Amendment Stimulated Decomposition of Maize Straw-Derived Biochar in a Sandy Loam Soil: A Short-Term Study

PubMed Central

Lu, Weiwei; Ding, Weixin; Zhang, Junhua; Zhang, Huanjun; Luo, Jiafa; Bolan, Nanthi

2015-01-01

This study examined the effect of nitrogen (N) on biochar stability in relation to soil microbial community as well as biochar labile components using δ13C stable isotope technology. A sandy loam soil under a long-term rotation of C3 crops was amended with biochar produced from maize (a C4 plant) straw in absence (BC0) and presence (BCN) of N and monitored for dynamics of carbon dioxide (CO2) flux, phospholipid fatty acids (PLFAs) profile and dissolved organic carbon (DOC) content. N amendment significantly increased the decomposition of biochar during the first 5 days of incubation (P < 0.05), and the proportions of decomposed biochar carbon (C) were 2.30% and 3.28% in BC0 and BCN treatments, respectively, during 30 days of incubation. The magnitude of decomposed biochar C was significantly (P < 0.05) higher than DOC in biochar (1.75%) and part of relatively recalcitrant biochar C was mineralized in both treatments. N amendment increased soil PLFAs concentration at the beginning of incubation, indicating that microorganisms were N-limited in test soil. Furthermore, N amendment significantly (P < 0.05) increased the proportion of gram-positive (G+) bacteria and decreased that of fungi, while no noticeable changes were observed for gram-negative (G−) bacteria and actinobacteria at the early stage of incubation. Our results indicated that N amendment promoted more efficiently the proliferation of G+ bacteria and accelerated the decomposition of relatively recalcitrant biochar C, which in turn reduced the stability of maize straw-derived biochar in test soil. PMID:26192282

The dielectric properties of soil-water mixtures at microwave frequencies

NASA Technical Reports Server (NTRS)

Wang, J. R.

1979-01-01

Recent measurements on the dielectric constants of soil-water mixtures show the existence of two frequency regions in which the dielectric behavior of these mixtures was quite different. At the frequencies of 1.4 GHz to 5 GHz, there were strong evidences that the variations of the dielectric (epsilon) with water content (W) depended on soil type. While the real part of epsilon for sandy soils rose rapidly with the increase in W, epsilon for the high-clay content soils rose only slowly with W. As a consequence, epsilon was generally higher for the sandy soils than for the high-clay content soils at a given W. On the other hand, most of the measurements at frequencies 1 GHz indicated the increase of epsilon with W independent of soil types. At a given W, epsilon' (sandy soil) approximately equals epsilon (high-clay content soil) within the precision of the measurements. These observational features can be satisfactorily interpreted in terms of a simple dielectric relaxation model, with an appropriate choice of the mean relaxation frequency f(m) and the range of the activation energy (beta). It was found that smaller f(m) and larger beta were required for the high-clay content soils than the sandy soils in order to be consistent with the measured data.

Aerobic De-Epoxydation of Trichothecene Mycotoxins by a Soil Bacterial Consortium Isolated Using In Situ Soil Enrichment.

PubMed

He, Wei-Jie; Yuan, Qing-Song; Zhang, You-Bing; Guo, Mao-Wei; Gong, An-Dong; Zhang, Jing-Bo; Wu, Ai-Bo; Huang, Tao; Qu, Bo; Li, He-Ping; Liao, Yu-Cai

2016-09-24

Globally, the trichothecene mycotoxins deoxynivalenol (DON) and nivalenol (NIV) are among the most widely distributed mycotoxins that contaminate small grain cereals. In this study, a bacterial consortium, PGC-3, with de-epoxydation activity was isolated from soil by an in situ soil enrichment method. Screening of 14 soil samples that were sprayed with DON revealed that 4 samples were able to biotransform DON into de-epoxydized DON (dE-DON). Among these, the PGC-3 consortium showed the highest and most stable activity to biotransform DON into dE-DON and NIV into dE-NIV. PGC-3 exhibited de-epoxydation activity at a wide range of pH (5-10) and temperatures (20-37 °C) values under aerobic conditions. Sequential subculturing with a continued exposure to DON substantially reduced the microbial population diversity of this consortium. Analyses of the 16S rDNA sequences indicated that PGC-3 comprised 10 bacterial genera. Among these, one species, Desulfitobacterium, showed a steady increase in relative abundance, from 0.03% to 1.55% (a 52-fold increase), as higher concentrations of DON were used in the subculture media, from 0 to 500 μg/mL. This study establishes the foundation to further develop bioactive agents that can detoxify trichothecene mycotoxins in cereals and enables for the characterization of detoxifying genes and their regulation.

Aerobic De-Epoxydation of Trichothecene Mycotoxins by a Soil Bacterial Consortium Isolated Using In Situ Soil Enrichment

PubMed Central

He, Wei-Jie; Yuan, Qing-Song; Zhang, You-Bing; Guo, Mao-Wei; Gong, An-Dong; Zhang, Jing-Bo; Wu, Ai-Bo; Huang, Tao; Qu, Bo; Li, He-Ping; Liao, Yu-Cai

2016-01-01

Globally, the trichothecene mycotoxins deoxynivalenol (DON) and nivalenol (NIV) are among the most widely distributed mycotoxins that contaminate small grain cereals. In this study, a bacterial consortium, PGC-3, with de-epoxydation activity was isolated from soil by an in situ soil enrichment method. Screening of 14 soil samples that were sprayed with DON revealed that 4 samples were able to biotransform DON into de-epoxydized DON (dE-DON). Among these, the PGC-3 consortium showed the highest and most stable activity to biotransform DON into dE-DON and NIV into dE-NIV. PGC-3 exhibited de-epoxydation activity at a wide range of pH (5–10) and temperatures (20–37 °C) values under aerobic conditions. Sequential subculturing with a continued exposure to DON substantially reduced the microbial population diversity of this consortium. Analyses of the 16S rDNA sequences indicated that PGC-3 comprised 10 bacterial genera. Among these, one species, Desulfitobacterium, showed a steady increase in relative abundance, from 0.03% to 1.55% (a 52-fold increase), as higher concentrations of DON were used in the subculture media, from 0 to 500 μg/mL. This study establishes the foundation to further develop bioactive agents that can detoxify trichothecene mycotoxins in cereals and enables for the characterization of detoxifying genes and their regulation. PMID:27669304

[Correlation Among Soil Organic Carbon, Soil Inorganic Carbon and the Environmental Factors in a Typical Oasis in the Southern Edge of the Tarim Basin].

PubMed

Gong, Lu; Zhu, Mei-ling; Liu, Zeng-yuan; Zhang, Xue-ni; Xie, Li-na

2016-04-15

We analyzed the differentiation among the environmental factors and soil organic/inorganic carbon contents of irrigated desert soil, brown desert soil, saline soil and aeolian sandy soil by classical statistics methods, and studied the correlation between soil carbon contents and the environmental factor by redundancy analysis (RDA) in a typical oasis of Yutian in the southern edge of the Tarim Basin. The results showed that the average contents of soil organic carbon and soil inorganic carbon were 2.51 g · kg⁻¹ and 25.63 g · kg⁻¹ respectively. The soil organic carbon content of the irrigated desert soil was significantly higher than those of brown desert soil, saline soil and aeolian sandy soil, while the inorganic carbon content of aeolian sandy soil was significantly higher than those of other soil types. The soil moisture and nutrient content were the highest in the irrigated desert soil and the lowest in the aeolian sandy sail. All soil types had high degree of salinization except the irrigated desert soil. The RDA results showed that the impacts of environmental factors on soil carbon contents ranked in order of importance were total nitrogen > available phosphorus > soil moisture > ground water depth > available potassium > pH > total salt. The soil carbon contents correlated extremely significantly with total nitrogen, available phosphorus, soil moisture and ground water depth (P < 0.01), and it correlated significantly with available potassium and pH (P < 0.05). There was no significant correlation between soil carbon contents and other environmental factors (P > 0.05).

[Moderately haloalkaliphilic aerobic methylobacteria].

PubMed

Trotsenko, Iu A; Doronina, N V; Li, Ts D; Reshetnikov, A S

2007-01-01

Aerobic methylobacteria utilizing oxidized and substituted methane derivatives as carbon and energy sources are widespread in nature and involved in the global carbon cycle, being a unique biofilter on the path of these C1 compounds from different ecosystems to the atmosphere. New data on the biological features of moderately halophilic, neutrophilic, and alkaliphilic methylobacteria isolated from biotopes with higher osmolarity (seas, saline and soda lakes, saline soils, and deteriorating marble) are reviewed. Particular attention is paid to the latest advances in the study of the mechanisms of osmoadaptation of aerobic moderately haloalkaliphilic methylobacteria: formation of osmolytes, in particular, molecular and genetic aspects of biosynthesis of the universal bioprotectant ectoine. The prospects for further studies of the physiological and biochemical principles of haloalkalophily and for the application of haloalkaliphilic aerobic methylobacteria in biosynthesis and biodegradation are discussed.

[Variations of soil fertility level in red soil region under long-term fertilization].

PubMed

Yu, Han-qing; Xu, Ming-gang; Lü, Jia-long; Bao, Yao-xian; Sun, Nan; Gao, Ju-sheng

2010-07-01

Based on the long-term (1982-2007) field experiment of "anthropogenic mellowing of raw soil" at the Qiyang red soil experimental station under Chinese Academy of Agricultural Sciences, and by using numerical theory, this paper studied the variations of the fertility level of granite red soil, quaternary red soil, and purple sandy shale soil under six fertilization patterns. The fertilization patterns included non-fertilization (CK), straw-returning without fertilizers (CKR), chemical fertilization (NPK), NPK plus straw-return (NPKR), rice straw application (M), and M plus straw-return (MR). The soil integrated fertility index (IFI) was significantly positively correlated with relative crop yield, and could better indicate soil fertility level. The IFI values of the three soils all were in the order of NPK, NPKR > M, MR > CK, CKR, with the highest value in treatment NPKR (0.77, 0.71, and 0.71 for granite red soil, quaternary red soil, and purple sandy shale soil, respectively). Comparing with that in the treatments of no straw-return, the IFI value in the treatments of straw return was increased by 6.72%-18.83%. A turning point of the IFI for all the three soils was observed at about 7 years of anthropogenic mellowing, and the annual increasing rate of the IFI was in the sequence of purple sandy shale soil (0.016 a(-1)) > quaternary red clay soil (0.011 a(-1)) > granite red soil (0.006 a(-1)). It was suggested that a combined application of organic and chemical fertilizers and/or straw return could be an effective and fast measure to enhance the soil fertility level in red soil region.

Long-term influence of tillage and fertilization on net carbon dioxide exchange rate on two soils with different textures.

PubMed

Feiziene, Dalia; Feiza, Virginijus; Slepetiene, Alvyra; Liaudanskiene, Inga; Kadziene, Grazina; Deveikyte, Irena; Vaideliene, Asta

2011-01-01

The importance of agricultural practices to greenhouse gas mitigation is examined worldwide. However, there is no consensus on soil organic carbon (SOC) content and CO emissions as affected by soil management practices and their relationships with soil texture. No-till (NT) agriculture often results in soil C gain, though, not always. Soil net CO exchange rate (NCER) and environmental factors (SOC, soil temperature [T], and water content [W]), as affected by soil type (loam and sandy loam), tillage (conventional, reduced, and NT), and fertilization, were quantified in long-term field experiments in Lithuania. Soil tillage and fertilization affected total CO flux (heterotrophic and autotrophic) through effect on soil SOC sequestration, water, and temperature regime. After 11 yr of different tillage and fertilization management, SOC content was 23% more in loam than in sandy loam. Long-term NT contributed to 7 to 27% more SOC sequestration on loam and to 29 to 33% more on sandy loam compared with reduced tillage (RT) or conventional tillage (CT). Soil water content in loam was 7% more than in sandy loam. Soil gravimetric water content, averaged across measurement dates and fertilization treatments, was significantly less in NT than CT and RT in both soils. Soil organic carbon content and water storage capacity of the loam and sandy loam soils exerted different influences on NCER. The NCER from the sandy loam soil was 13% greater than that from the loam. In addition, NCER was 4 to 9% less with NT than with CT and RT systems on both loam and sandy loam soils. Application of mineral NPK fertilizers promoted significantly greater NCER from loam but suppressed NCER by 15% from sandy loam. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Effect of cement injection on sandy soil slope stability, case study: slope in Petang district, Badung regency

NASA Astrophysics Data System (ADS)

Arya, I. W.; Wiraga, I. W.; GAG Suryanegara, I.

2018-01-01

with cement injection interval 5 cm and third model is soil with cement injection interval 10 cm. The result is the shear strength (ϕ value) the soil is increase from 32.02° to 47.57°. The increase value of internal friction angle (ϕ) shows that an increase in shear strength of the cement improved soil. While, the value of cohesion (c) is zero indicating there is no cohesion in the soil. This is common for sand soil or sandy soil. The calculation of safety factor with GeoStructural Analysis obtained an increase of safety factor from 0.78 if the soil without cement injection to 1.07 and 1.17 if the soil is injected with cement at a distance of 10 cm and 5 cm.

Root morphology, hydraulic conductivity and plant water relations of high-yielding rice grown under aerobic conditions.

PubMed

Kato, Yoichiro; Okami, Midori

2011-09-01

Increasing physical water scarcity is a major constraint for irrigated rice (Oryza sativa) production. 'Aerobic rice culture' aims to maximize yield per unit water input by growing plants in aerobic soil without flooding or puddling. The objective was to determine (a) the effect of water management on root morphology and hydraulic conductance, and (b) their roles in plant-water relationships and stomatal conductance in aerobic culture. Root system development, stomatal conductance (g(s)) and leaf water potential (Ψ(leaf)) were monitored in a high-yielding rice cultivar ('Takanari') under flooded and aerobic conditions at two soil moisture levels [nearly saturated (> -10 kPa) and mildly dry (> -30 kPa)] over 2 years. In an ancillary pot experiment, whole-plant hydraulic conductivity (soil-leaf hydraulic conductance; K(pa)) was measured under flooded and aerobic conditions. Adventitious root emergence and lateral root proliferation were restricted even under nearly saturated conditions, resulting in a 72-85 % reduction in total root length under aerobic culture conditions. Because of their reduced rooting size, plants grown under aerobic conditions tended to have lower K(pa) than plants grown under flooded conditions. Ψ(leaf) was always significantly lower in aerobic culture than in flooded culture, while g(s) was unchanged when the soil moisture was at around field capacity. g(s) was inevitably reduced when the soil water potential at 20-cm depth reached -20 kPa. Unstable performance of rice in water-saving cultivations is often associated with reduction in Ψ(leaf). Ψ(leaf) may reduce even if K(pa) is not significantly changed, but the lower Ψ(leaf) would certainly occur in case K(pa) reduces as a result of lower water-uptake capacity under aerobic conditions. Rice performance in aerobic culture might be improved through genetic manipulation that promotes lateral root branching and rhizogenesis as well as deep rooting.

Warming intensify CO2 flux and nutrient release from algal wrack subsidies on sandy beaches.

PubMed

Lastra, Mariano; López, Jesús; Rodil, Iván F

2018-04-18

Algal wrack subsidies underpin most of the food web structure of exposed sandy beaches and are responsible of important biogeochemical processes that link marine and terrestrial ecosystems. The response in decomposition of algal wrack deposits to global warming has not been studied in ocean-exposed sandy beaches to date. With this aim, passive open top chambers (OTCs) were used to increase soil temperature within the range predicted by the IPCC for western Europe (between 0.5 and 1.5°C), following the hypothesis that the biogeochemical processing of macroalgal wrack subsidies would accelerate in response to temperature increase. The effect of temperature manipulation on three target substrates: fresh and aged macroalgae, and bare sand, was tested. Results indicated that a small warming (<0.5°C) affected the wrack decomposition process through traceable increases in soil respiration through CO 2 flux, inorganic nutrients within the interstitial environment (N and P), sediment organic contents measured through the amount of proteins and microbial pool through the total soil DNA. The different responses of soil variables in the studied substrates indicated that the decomposition stage of stranded macroalgae influences the biogeochemical processing of organic matter in sandy beaches. Thus, CO 2 fluxes, releases of organic and inorganic nutrients and microbial activity intensify in aged wrack deposits. Our results predict that expected global warming will increase the release of inorganic nutrients to the coastal ocean by 30% for the N (21 Gg/year) and 5.9% for P (14 Gg/year); that increase for the flow of C to the atmosphere as CO 2 was estimated in 8.2% (523 Gg/year). This study confirms the key role of sandy beaches in recycling ocean-derived organic matter, highlighting their sensitivity to a changing scenario of global warming that predicts significant increases in temperature over the next few decades. © 2018 John Wiley & Sons Ltd.

Stability Behavior and Thermodynamic States of Iron and Manganese in Sandy Soil Aquifer, Manukan Island, Malaysia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Chin Yik, E-mail: cy_lin_ars@hotmail.com; Abdullah, Mohd. Harun; Musta, Baba

2011-03-15

A total of 20 soil samples were collected from 10 boreholes constructed in the low lying area, which included ancillary samples taken from the high elevation area. Redox processes were investigated in the soil as well as groundwater in the shallow groundwater aquifer of Manukan Island, Sabah, Malaysia. Groundwater samples (n = 10) from each boreholes were also collected in the low lying area to understand the concentrations and behaviors of Fe and Mn in the dissolved state. This study strives to obtain a general understanding of the stability behaviors on Fe and Mn at the upper unsaturated and themore » lower-saturated soil horizons in the low lying area of Manukan Island as these elements usually play a major role in the redox chemistry of the shallow groundwater. Thermodynamic calculations using PHREEQC showed that the groundwater samples in the study area are oversaturated with respect to goethite, hematite, Fe(OH){sub 3} and undersaturated with respect to manganite and pyrochroite. Low concentrations of Fe and Mn in the groundwater might be probably due to the lack of minerals of iron and manganese oxides, which exist in the sandy aquifer. In fact, high organic matters that present in the unsaturated horizon are believed to be responsible for the high Mn content in the soil. It was observed that the soil samples collected from high elevation area (BK) comprises considerable amount of Fe in both unsaturated (6675.87 mg/kg) and saturated horizons (31440.49 mg/kg) compared to the low Fe content in the low lying area. Based on the stability diagram, the groundwater composition lies within the stability field for Mn{sup 2+} and Fe{sup 2+} under suboxic condition and very close to the FeS/Fe{sup 2+} stability boundary. This study also shows that both pH and Eh values comprise a strong negative value thus suggesting that the redox potential is inversely dependent on the changes of pH.« less

Patterns of Arbuscular Mycorrhizal Fungal Distribution on Mainland and Island Sandy Coastal Plain Ecosystems in Brazil.

PubMed

da Silva, Iolanda Ramalho; de Souza, Francisco Adriano; da Silva, Danielle Karla Alves; Oehl, Fritz; Maia, Leonor Costa

2017-10-01

Although sandy coastal plains are important buffer zones to protect the coast line and maintain biological diversity and ecosystem services, these ecosystems have been endangered by anthropogenic activities. Thus, information on coastal biodiversity and forces shaping coastal biological diversity are extremely important for effective conservation strategies. In this study, we aimed to compare arbuscular mycorrhizal (AM) fungal communities from soil samples collected on the mainland and nearby islands located in Brazilian sandy coastal plain ecosystems (Restingas) to get information about AM fungal biogeography and identify factors shaping these communities. Soil samples were collected in 2013 and 2014 on the beachfront of the tropical sandy coastal plain at six sites (three island and three mainland locations) across the northeast, southeast, and south regions of Brazil. Overall, we recorded 53 AM fungal species from field and trap culture samples. The richness and diversity of AM fungal species did not differ between mainland and island locations, but AM fungal community assemblages were different between mainland and island environments and among most sites sampled. Glomeromycota communities registered from island samples showed higher heterogeneity than communities from mainland samples. Sandy coastal plains harbor diverse AM fungal communities structured by climatic, edaphic, and spatial factors, while the distance from the colonizing source (mainland environments) does not strongly affect the AM fungal communities in Brazilian coastal environments.

Pyrosequence analysis of bacterial communities in aerobic bioreactors treating polycyclic aromatic hydrocarbon-contaminated soil

PubMed Central

Richardson, Stephen D.; Aitken, Michael D.

2011-01-01

Two aerobic, lab-scale, slurry-phase bioreactors were used to examine the biodegradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil and the associated bacterial communities. The two bioreactors were operated under semi-continuous (draw-and-fill) conditions at a residence time of 35 days, but one was fed weekly and the other monthly. Most of the quantified PAHs, including high-molecular-weight compounds, were removed to a greater extent in the weekly-fed bioreactor, which achieved total PAH removal of 76%. Molecular analyses, including pyrosequencing of 16S rRNA genes, revealed significant shifts in the soil bacterial communities after introduction to the bioreactors and differences in the abundance and types of bacteria in each of the bioreactors. The weekly-fed bioreactor displayed a more stable bacterial community with gradual changes over time, whereas the monthly-fed bioreactor community was less consistent and may have been more strongly influenced by the influx of untreated soil during feeding. Phylogenetic groups containing known PAH-degrading bacteria previously identified through stable-isotope probing of the untreated soil were differentially affected by bioreactor conditions. Sequences from members of the Acidovorax and Sphingomonas genera, as well as the uncultivated ‘‘Pyrene Group 2’’ were abundant in the bioreactors. However, the relative abundances of sequences from the Pseudomonas, Sphingobium, and Pseudoxanthomonas genera, as well as from a group of unclassified anthracene degraders, were much lower in the bioreactors compared to the untreated soil. PMID:21369833

Aerobic biotransformation of N-nitrosodimethylamine and N-nitrodimethylamine in methane and benzene amended soil columns

NASA Astrophysics Data System (ADS)

Weidhaas, Jennifer; Dupont, R. Ryan

2013-07-01

Aerobic biotransformation of N-nitrosodimethylamine (NDMA), an emerging contaminant of concern, and its structural analog N-nitrodimethylamine (DMN), was evaluated in benzene and methane amended groundwater passed through laboratory scale soil columns. Competitive inhibition models were used to model the kinetics for NDMA and DMN cometabolism accounting for the concurrent degradation of the growth and cometabolic substrates. Transformation capacities for NDMA and DMN with benzene (13 and 23 μg (mg cells)- 1) and methane (0.14 and 8.4 μg (mg cells)- 1) grown cultures, respectively are comparable to those presented in the literature, as were first order endogenous decay rates estimated to be 2.1 × 10- 2 ± 1.7 × 10- 3 d- 1 and 6.5 × 10- 1 ± 7.1 × 10- 1 d- 1 for the methane and benzene amended cultures, respectively. These studies highlight possible attenuation mechanisms and rates for NDMA and DMN biotransformation in aerobic aquifers undergoing active remediation, natural attenuation or managed aquifer recharge with treated wastewater (i.e., reclaimed water).

Transport of gadolinium- and arsenic-based pharmaceuticals in saturated soil under various redox conditions.

PubMed

Menahem, Adi; Dror, Ishai; Berkowitz, Brian

2016-02-01

The release of pharmaceuticals and personal care products (PPCPs) to the soil-water environment necessitates understanding of PPCP transport behavior under conditions that account for dynamic flow and varying redox states. This study investigates the transport of two organometallic PPCPs, Gd-DTPA and roxarsone (arsenic compound) and their metal salts (Gd(NO3)3, AsNaO2); Gd-DTPA is used widely as a contrasting agent for MRI, while roxarsone is applied extensively as a food additive in the broiler poultry industry. Here, we present column experiments using sand and Mediterranean red sandy clay soil, performed under several redox conditions. The metal salts were almost completely immobile. In contrast, transport of Gd-DTPA and roxarsone was affected by the soil type. Roxarsone was also affected by the different redox conditions, showing delayed breakthrough curves as the redox potential became more negative due to biological activity (chemically-strong reducing conditions did not affect the transport). Mechanisms that include adsorptive retardation for aerobic and nitrate-reducing conditions, and non-adsorptive retardation for iron-reducing, sulfate-reducing and biologically-strong reducing conditions, are suggested to explain the roxarsone behavior. Gd-DTPA is found to be a stable complex, with potential for high mobility in groundwater systems, whereas roxarsone transport through groundwater systems is affected by redox environments, demonstrating high mobility under aerobic and nitrate-reducing conditions and delayed transport under iron-reducing, sulfate-reducing and biologically-strong reducing conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Simulation of effects of soil properties and plants on soil water-salt movement with reclaimed water irrigation by ENVIRO-GRO model].

PubMed

Lü, Si-Dan; Chen, Wei-Ping; Wang, Mei-E

2012-12-01

In order to promote safe irrigation with reclaimed water and prevent soil salinisation, the dynamic transport of salts in urban soils of Beijing under irrigation of reclaimed water was simulated by ENVIRO-GRO model in this study. The accumulation trends and profile distribution of soil salinity were predicted. Simultaneously, the effects of different soil properties and plants on soil water-salt movement and salt accumulation were investigated. Results indicated that soil salinity in the profiles reached uniform equilibrium conditions by repeated simulation, with different initial soil salinity. Under the conditions of loam and clay loam soil, salinity in the profiles increased over time until reaching equilibrium conditions, while under the condition of sandy loam soil, salinity in the profiles decreased over time until reaching equilibrium conditions. The saturated soil salinity (EC(e)) under equilibrium conditions followed an order of sandy loam < loam < clay loam. Salt accumulations in Japan euonymus and Chinese pine were less than that in Blue grass. The temporal and spatial distributions of soil salinity were also different in these three types of plants. In addition, the growth of the plants was not influenced by soil salinity (except clay loam), but mild soil salinization occurred under all conditions (except sandy loam).

[Characteristics of soil microorganisms and soil nutrients in different sand-fixation shrub plantations in Kubuqi Desert, China].

PubMed

Zhang, Li-Xin; Duan, Yu Xi; Wang, Bo; Wang, Wei Feng; Li, Xiao Jing; Liu, Jin Jie

2017-12-01

Three types of sand-fixation shrub plantations, including Artemisia ordosica + Hedysarum fruticosum, Caragana korshinskii and Salix psammophila, were selected in the eastern area of Kubuqi Desert to study the changes in soil microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN), quantities of soil microorganisms, contents of soil nutrients and the relations among these variables under the different plantation types and shifting sandy land. The restoration effects of each plantation type on soil quality were assessed by synthetic index method. The results showed that the contents of soil organic matter, total nitrogen and phosphorus, and available nitrogen and phosphorus under different plantations were all significantly greater than those under shifting sandy land, and the order of increase was A. ordosica + H. fruticosum ＞ C. korshinskii ＞ S. psammophila. The soil nutrient contents decreased with the increase of soil depth under all plantation types. The quantities of soil microorganisms and the contents of soil MBC and MBN under the plantations were higher at different degrees than those under shifting sandy land. MBC, MBN and the relative numbers of bacteria under A. ordosica+H. fruticosum plantation were higher than those under C. korshinskii plantation and S. psammophila plantation. The relative numbers of fungi and actinobacteria decreased in the order of C. korshinskii ＞ S. psammophila ＞ A. ordosica + H. fruticosum. The relative number of bacteria, MBC and MBN under the plantations were mainly affected by the contents of soil organic matter, total nitrogen, total phosphorus, available nitrogen, available phosphorus, as well as C/N, and the relative numbers of actinobacteria and fungi were primarily affected by the contents of soil total phosphorus, available nitrogen and available phosphorus. Soil quality was ranked in the order of A. ordosica + H. fruticosum ＞ C. korshinskii ＞ S. psammophila ＞ shifting sandy land. These results

Enhanced retention of linuron, alachlor and metalaxyl in sandy soil columns intercalated with wood barriers.

PubMed

Rodríguez-Cruz, M S; Ordax, J M; Arienzo, M; Sánchez-Martín, M J

2011-03-01

A study has been made of the effect a reactive barrier made of pine (softwood) or oak (hardwood) wood intercalated in a sandy soil column has on the retention of linuron, alachlor and metalaxyl (pesticides with contrasting physicochemical characteristics). The leaching of pesticides has been carried out under a saturated flow regime and breakthrough curves (BTCs) have been obtained at flow rates of 1 m Lmin(-1) (all pesticides) and 3 m Lmin(-1) (linuron). The cumulative curves in the unmodified soil indicate a leaching of pesticides >80% of the total amount of compound added. After barrier intercalation, linuron leaching decreases significantly and a modification of the leaching kinetics of alachlor and metalaxyl has been observed. The theoretical R factors increased ∼2.6-3.3, 1.2-1.6-fold, and 1.4-1.7-fold and the concentration of the maximum peak decreased ∼6-12-fold, 2-4-fold and 1.2-2-fold for linuron, alachlor and metalaxyl, respectively. When considering the three pesticides, significant correlations have been found between the theoretical retardation factor (R) and the pore volume corresponding to the maximum peaks of the BTCs (r=0.77; p<0.05) or the total volume leached (r=-0.78; p<0.05). The results reveal the efficacy of reactive wood barriers to decrease the leaching of pesticides from point sources of pollution depends on the type of wood, the hydrophobicity of the pesticide and the adopted water flow rate. Pine was more effective than oak in decreasing the leaching of hydrophobic pesticide linuron or in decreasing the maximum peak concentration of the less hydrophobic pesticides in soils. Efficacy of these wood barriers was limited for the least hydrophobic pesticide metalaxyl. Copyright © 2010 Elsevier Ltd. All rights reserved.

Sorption and biodegradability of sludge bacterial extracellular polymers in soil and their influence on soil copper behavior.

PubMed

Zhou, L X; Zhou, S G; Zhan, X H

2004-01-01

Bacterial extracellular polymers (BEP) affect the translocation and fate of organic and inorganic pollutants in terrestrial and aquatic ecosystems. In this study, BEP from activated sludge was compared with sludge dissolved organic matter (DOM) in terms of behavior and effects on the mobilization and bioavailability of Cu in a well-aged Cu-contaminated orchard sandy loam. Addition of sludge BEP (10-200 mg dissolved organic carbon [DOC] L(-1)) to the soil resulted in 1.6- to 12.8-fold-higher soil soluble Cu concentration over the control and 1.3- to 2.2-fold over sludge DOM of the same concentration. Consequently, the Cu uptake by the ryegrass (Lolium perenne L., cv. Target) grown in the soil was increased by 31% due to interval watering of 100 mg DOC L(-1) of sludge BEP solution in a 35-d period. The influence of sludge BEP on mobilizing soil Cu could be maintained as long as 60 d or more, depending on BEP biodegradation status. The findings that sludge BEP promoted Cu mobilization and bioavailability could be attributed to less adsorption of BEP by soil, slow degradation, and higher affinity with Cu. For example, after 3 wk of aerobic incubation, the soluble Cu present in the sludge DOM-treated soil was reduced to about the level of the control, while the concentration of soluble Cu in BEP-treated soil was 6.2 times higher than that in the control. Therefore, sludge BEP could act as a facilitated-transport carrier of Cu. The environmental risk of Cu should receive much attention if BEP is incorporated into soils.

[Effects of desertification on C and N storages in grassland ecosystem on Horqin sandy land].

PubMed

Zhao, Ha-lin; Li, Yu-qiang; Zhou, Rui-lian

2007-11-01

Sandy grassland is widespread in northern China, where desertification is very common because of overgrazing and estrepement. However, little is known about the effects of desertification on grassland C and N storages in this region. A field survey was conducted on Horqin sandy grassland, and desertification gradients were established to evaluate the effects of desertification on C and N storages in soil, plant, and litter. The results showed that desertification had deep effects on the contents and storages of grassland C and N. The C and N contents and storages in the grassland decreased significantly with increasing desertification degree. Comparing with those in un-desertified grassland, the C and N contents in lightly, moderately, heavily, and severely desertified grasslands decreased by 56.06% and 48.72%, 78.43% and 74.36%, 88.95% and 84.62%, and 91.64% and 84.62% in 0-100 cm soil layer, and by 8.61% and 6.43%, 0.05% and 25.71%, 2.58% and 27.14%, and 8. 61% and 27. 86% in plant components, respectively. Relevantly, the C and N storages decreased by 50.95% and 43.38%, 75.19% and 71.04%, 86.76% and 81.48%, and 91.17% and 83.17% in plant underground components in 0-100 cm soil layer, and by 25.08% and 27.62%, 30.90% and 46.55%, 73.84% and 80.62%, and 90.89% and 87.31% in plant aboveground components, respectively. In 2000, the total area of desertified grassland in Horqin sandy land was 30152. 7 km2, and the C and N loss via desertification reached up to 107.53 and 9.97 Mt, respectively. Correlation analysis indicated that the decrease of soil C and N contents was mainly come from the decreased soil fine particles caused by wind erosion in the process of desertification, and the degradation of soil texture- and nutrient status led finally to the rapid decrease of C and N storages in plant biomass and litter.

Virus and bacteria transport in a sandy aquifer, Cape Cod, MA

USGS Publications Warehouse

Bales, Roger C.; Li, Shimin; Maguire, Kimberly M.; Yahya, Moyasar T.; Gerba, Charles P.; Harvey, Ronald W.

1995-01-01

Transport of the bacteriophage PRD-1, bacteria, and latex microspheres was studied in a sandy aquifer under natural-gradient conditions. The field injection was carried out at the U.S. Geological Survey's Toxic Substances Hydrology research site on Cape Cod. The three colloids and a salt tracer (Br−) moved along the same path. There was significant attenuation of the phage, with PRD-1 peak concentrations less than 0.001 percent of Br− peaks 6 m from the source; but the low detection limit (one per ml) enabled tracking movement of the PRD-1 plume for 12 m downgradient over the 25-day experiment. Attenuation of phage was apparently due to retention on soil particles (adsorption). Attenuation of bacteria and microspheres was less, with peak concentrations 6 m from the source on the order of 10 and 0.4 percent of Br−, respectively. Injection of a high-pH pulse of water 20 days into the experiment resulted in significant remobilization of retained phage, demonstrating that attached phage remained viable, and that PRD-1 attachment to and detachment from the sandy soil particles was highly pH dependent. Phage behavior in this experiment, i.e. attenuation at pH 5.7 and rapid resuspension at pH 6–8, was consistent with that observed previously in laboratory column studies. Results illustrate that biocolloids travel in a fairly narrow plume in sandy (relatively homogeneous) media, with virus concentrations dropping below detection limit several meters away from the source; bacteria concentrations above detection limits can persist over longer distances.

Analysis of volatile organic compound from Elaeis guineensis inflorescences planted on different soil types in Malaysia

NASA Astrophysics Data System (ADS)

Muhamad Fahmi, M. H.; Ahmad Bukhary, A. K.; Norma, H.; Idris, A. B.

2016-11-01

The main attractant compound for Eleidobius kamerunicus to male spikelet Elaeis guineensis (oil palm) were determined by analyzing volatile organic compound extracted from E. guineenses inflorescences planted on different soil types namely peat soil, clay soil and sandy soil. Anthesizing male oil palm inflorescences were randomly choosen from palm aged between 4-5 years old age. Extraction of the volatiles from the oil palm inflorescences were performed by Accelerated Solvent Extraction method (ASE). The extracted volatile compound were determined by using gas chromatography-mass spectrometry. Out of ten identified compound, estragole was found to be a major compound in sandy soil (37.49%), clay soil (30.71%) and peat soil (27.79%). Other compound such as 9,12-octadecadieonic acid and n-hexadecanoic acid were found as major compound in peat soil (27.18%) and (7.45%); sandy soil (14.15 %) and (9.31%); and clay soil (30.23%) and (4.99%). This study shows that estragole was the predominant volatile compound detected in oil palm inflorescences with highly concentrated in palm planted in sandy soil type.

Removal of Fast Flowing Nitrogen from Marshes Restored in Sandy Soils

PubMed Central

Sparks, Eric L.; Cebrian, Just; Smith, Sara M.

2014-01-01

Groundwater flow rates and nitrate removal capacity from an introduced solution were examined for five marsh restoration designs and unvegetated plots shortly after planting and 1 year post-planting. The restoration site was a sandy beach with a wave-dampening fence 10 m offshore. Simulated groundwater flow into the marsh was introduced at a rate to mimic intense rainfall events. Restoration designs varied in initial planting density and corresponded to 25%, 50%, 75% and 100% of the plot area planted. In general, groundwater flow was slower with increasing planting density and decreased from year 0 to year 1 across all treatments. Nevertheless, removal of nitrate from the introduced solution was similar and low for all restoration designs (3–7%) and similar to the unvegetated plots. We suggest that the low NO3 − removal was due to sandy sediments allowing rapid flow of groundwater through the marsh rhizosphere, thereby decreasing the contact time of the NO3 − with the marsh biota. Our findings demonstrate that knowledge of the groundwater flow regime for restoration projects is essential when nutrient filtration is a target goal of the project. PMID:25353607

Understanding the hydrologic control of N cycle: Effect of water filled pore space on heterotrophic nitrification, denitrification and dissimilatory nitrate reduction to ammonium mechanisms in unsaturated soils

NASA Astrophysics Data System (ADS)

Mekala, C.; Nambi, Indumathi M.

2017-07-01

Irrigation practice will be effective if it supplies optimal water and nutrients to crops and act as a filter for contaminants leaching to ground water. There is always a scope for improving the fertilizer use efficiency and scheduling of wastewater irrigation if the fate and transport of nutrients particularly nitrogenous compounds in the soil are well understood. In the present study, nitrogen transport experiments for two different agricultural soils are performed under varying saturation 33, 57, 78% water filled pore space for sandy soil 1 and 52, 81 and 96% for loam soil 2. A HYDRUS 2D model with constructed wetland (CW2D) module could simulate aerobic nitrification and anoxic denitrification well for both soils and estimated the reaction kinetics. A hot spot of Dissimilatory Nitrate Reduction to Ammonium (DNRA) pathway has been observed at 81% moisture content for a loamy sand soil. The presence of high organic content and reductive soil environment (5.53 C/NO3- ratio; ORP = - 125 mV) results in ammonium accumulation of 16.85 mg in the soil. The overall observation from this study is nitrification occurs in a wide range of saturations 33-78% with highest at 57% whereas denitrification is significant at higher water saturations 57-78% for sandy soil texture. For a loamy sand soil, denitrification is dominant at 96% saturation with least nitrification at all saturation studies. The greatest nitrogen losses (> 90%) was observed for soil 2 while 30-70% for soil1. The slow dispersive subsurface transport with varying oxygen dynamics enhanced nitrogen losses from soil2 due to lesser soil permeability. This in turn, prevents NO3- leaching and groundwater contamination. This type of modeling study should be used before planning field experiments for designing optimal irrigation and fertigation schedules.

Plant-uptake of uranium: Hydroponic and soil system studies

USGS Publications Warehouse

Ramaswami, A.; Carr, P.; Burkhardt, M.

2001-01-01

Limited information is available on screening and selection of terrestrial plants for uptake and translocation of uranium from soil. This article evaluates the removal of uranium from water and soil by selected plants, comparing plant performance in hydroponic systems with that in two soil systems (a sandy-loam soil and an organic-rich soil). Plants selected for this study were Sunflower (Helianthus giganteus), Spring Vetch (Vicia sativa), Hairy Vetch (Vicia villosa), Juniper (Juniperus monosperma), Indian Mustard (Brassica juncea), and Bush Bean (Phaseolus nanus). Plant performance was evaluated both in terms of the percent uranium extracted from the three systems, as well as the biological absorption coefficient (BAC) that normalized uranium uptake to plant biomass. Study results indicate that uranium extraction efficiency decreased sharply across hydroponic, sandy and organic soil systems, indicating that soil organic matter sequestered uranium, rendering it largely unavailable for plant uptake. These results indicate that site-specific soils must be used to screen plants for uranium extraction capability; plant behavior in hydroponic systems does not correlate well with that in soil systems. One plant species, Juniper, exhibited consistent uranium extraction efficiencies and BACs in both sandy and organic soils, suggesting unique uranium extraction capabilities.

Consumption of methane by soils.

PubMed

Dueñas, C; Fernández, M C; Carretero, J; Pérez, M; Liger, E

1994-05-01

Measurements of the methane flux and methane concentration profiles in soil air are presented. The flux of methane from the soil is calculated by two methods: a) Direct by placing a static open chamber at the soil surface. b) Indirect, using the (222)Rn concentrations profile and the (222)Rn flux in the soil surface in parallel with the methane concentration ((222)Rn calibrated fluxes). The methane flux has been determined in two kinds of soils (sandy and loamy) in the surroundings of Málaga (SPAIN). The directly measured methane fluxes at all investigated sites is higher than methane fluxes derived from "Rn calibrated fluxes". Atmospheric methane is consumed by soils, mean direct flux to the atmosphere were - 0.33 g m(-2)yr-1. The direct methane flux is the same within the measuring error in sandy and loamy soils. The influence of the soil parameters on the methane flux indicates that microbial decomposition of methane is primarily controlled by the transport of methane.

Influence of soil texture on hydraulic properties and water relations of a dominant warm-desert phreatophyte.

PubMed

Hultine, K R; Koepke, D F; Pockman, W T; Fravolini, A; Sperry, J S; Williams, D G

2006-03-01

We investigated hydraulic constraints on water uptake by velvet mesquite (Prosopis velutina Woot.) at a site with sandy-loam soil and at a site with loamy-clay soil in southeastern Arizona, USA. We predicted that trees on sandy-loam soil have less negative xylem and soil water potentials during drought and a lower resistance to xylem cavitation, and reach E(crit) (the maximum steady-state transpiration rate without hydraulic failure) at higher soil water potentials than trees on loamy-clay soil. However, minimum predawn leaf xylem water potentials measured during the height of summer drought were significantly lower at the sandy-loam site (-3.5 +/- 0.1 MPa; all errors are 95% confidence limits) than at the loamy-clay site (-2.9 +/- 0.1 MPa). Minimum midday xylem water potentials also were lower at the sandy-loam site (-4.5 +/- 0.1 MPa) than at the loamy-clay site (-4.0 +/- 0.1 MPa). Despite the differences in leaf water potentials, there were no significant differences in either root or stem xylem embolism, mean cavitation pressure or Psi(95) (xylem water potential causing 95% cavitation) between trees at the two sites. A soil-plant hydraulic model parameterized with the field data predicted that E(crit) approaches zero at a substantially higher bulk soil water potential (Psi(s)) on sandy-loam soil than on loamy-clay soil, because of limiting rhizosphere conductance. The model predicted that transpiration at the sandy-loam site is limited by E(crit) and is tightly coupled to Psi(s) over much of the growing season, suggesting that seasonal transpiration fluxes at the sandy-loam site are strongly linked to intra-annual precipitation pulses. Conversely, the model predicted that trees on loamy-clay soil operate below E(crit) throughout the growing season, suggesting that fluxes on fine-textured soils are closely coupled to inter-annual changes in precipitation. Information on the combined importance of xylem and rhizosphere constraints to leaf water supply across soil

Variation and significance of surface heat after the mechanical sand control of Qinghai-Tibet Railway was covered with sandy sediments

NASA Astrophysics Data System (ADS)

Xie, Shengbo; Qu, Jianjun; Mu, Yanhu; Xu, Xiangtian

Mechanical control of drifting sand used to protect the Qinghai-Tibet Railway from sand damage inevitably results in sand deposition, and the change in radiation and heat flux after the ground surface is covered with sandy sediments remains unclear. These variations were studied in this work through field observations along with laboratory analyses and tests. After the ground surface was covered with sandy sediments produced by the mechanical control of sand in the Qinghai-Tibet Railway, the reflectivity increased, and the annual average reflectivity on the surface covered with sandy sediments was higher than that without sandy sediments, with the value increasing by 0.043. Moreover, the surface shortwave radiation increased, whereas the surface net radiation decreased. The annual average value of the surface shortwave radiant flux density on the sandy sediments was higher than that without sandy sediments, with the value increasing by 7.291 W·m-2. The annual average value of the surface net radiant flux density on the sandy sediments decreased by 9.639 W·m-2 compared with that without sandy sediments. The soil heat flux also decreased, and the annual average value of the heat flux in the sandy sediments decreased by 0.375 W·m-2 compared with that without sandy sediments. These variations caused the heat source on the surface of sandy sediments underground to decrease, which is beneficial for preventing permafrost from degradation in the section of sand control of the railway.

Analysis of Long Wave Infrared (LWIR) Soil Data to Predict Reflectance Response

DTIC Science & Technology

2009-08-01

Aridisol red-orange sandy soil 6% x 16% 61 12% smectite Aridisol grey calcareous silty soil x 19% 49 22% smectite ...trace 16% 59 20% smectite ; grain size analysis of fraction finer than 2 mm indicates 35% finer than 20 micrometer (12% finer than 5 micrometer...Entisol red-orange sandy loam/alluvium see comment 8% x 10% 72 7% smectite ; 47% finer than 20 μm (22% finer than 5 μm) Entisol sandy

Winter Survival of Meloidogyne incognita in Six Soil Types

PubMed Central

Windham, G. L.; Barker, K. R.

1988-01-01

Winter survival of Meloidogyne incognita in six soil types (Fuquay sand, Norfolk loamy sand, Portsmouth loamy sand, muck, Cecil sandy clay loam, and Cecil sandy clay) was determined in microplots at one location from November 1981 to May 1982 and from November 1982 to March 1983. Survival, based on second-stage juveniles (J2) of M. incognita, from November 1981 until May 1982 ranged from 1% in the muck soil to 6% in a Cecil sandy clay loam, but survival rates were much higher the next year following a winter with higher average temperatures. Survival rates of J2 from November to March ranged from 20 to 40% the first winter and from 38 to 87% the second. Soil type did not have a striking effect on the overwintering capabilities ofM. incognita. There were no differences between clay and sand soils, whereas survival of J2 in the muck tended to be lower than in the mineral soils. PMID:19290193

Winter Survival of Meloidogyne incognita in Six Soil Types.

PubMed

Windham, G L; Barker, K R

1988-01-01

Winter survival of Meloidogyne incognita in six soil types (Fuquay sand, Norfolk loamy sand, Portsmouth loamy sand, muck, Cecil sandy clay loam, and Cecil sandy clay) was determined in microplots at one location from November 1981 to May 1982 and from November 1982 to March 1983. Survival, based on second-stage juveniles (J2) of M. incognita, from November 1981 until May 1982 ranged from 1% in the muck soil to 6% in a Cecil sandy clay loam, but survival rates were much higher the next year following a winter with higher average temperatures. Survival rates of J2 from November to March ranged from 20 to 40% the first winter and from 38 to 87% the second. Soil type did not have a striking effect on the overwintering capabilities ofM. incognita. There were no differences between clay and sand soils, whereas survival of J2 in the muck tended to be lower than in the mineral soils.

Effect of soil and vegetation on growth of planted white spruce.

Treesearch

Donald A. Perala

1987-01-01

White spruce container stock grew better on a sandy loam soil than on a silty clay, and much better without herbaceous competitions. Herbaceous competition was less vigorous on the sandy loam soil following glyphosate treatment, but was more vigorous on the silty clay. Certain spruce genotypes excelled under different field environments.

Spatial patterns and natural recruitment of native shrubs in a semi-arid sandy land.

PubMed

Wu, Bo; Yang, Hongxiao

2013-01-01

Passive restoration depending on native shrubs is an attractive approach for restoring desertified landscapes in semi-arid sandy regions. We sought to understand the relationships between spatial patterns of native shrubs and their survival ability in sandy environments. Furthermore, we applied our results to better understand whether passive restoration is feasible for desertified landscapes in semi-arid sandy regions. The study was conducted in the semi-arid Mu Us sandy land of northern China with the native shrub Artemisia ordosica. We analyzed population structures and patterns of A. ordosica at the edges and centers of land patches where sand was stabilized by A. ordosica-dominated vegetation. Saplings were more aggregated than adults, and both were more aggregated at the patch edges than at the patch centers. At the patch edges, spatial association of the saplings with the adults was mostly positive at distances 0.3-6.6 m, and turned from positive to neutral, and even negative, at other distances. At the patch centers, the saplings were spaced almost randomly around the adults, and their distances from the adults did not seem to affect their locations. A greater number of A. ordosica individuals emerged at the patch edges than at the patch centers. Such patterns may have resulted from their integrative adjustment to specific conditions of soil water supply and sand drift intensity. These findings suggest that in semi-arid sandy regions, native shrubs that are well-adapted to local environments may serve as low-cost and competent ecological engineers that can promote the passive restoration of surrounding patches of mobile sandy land.

Processing Protocol for Soil Samples Potentially ...

EPA Pesticide Factsheets

Method Operating Procedures This protocol describes the processing steps for 45 g and 9 g soil samples potentially contaminated with Bacillus anthracis spores. The protocol is designed to separate and concentrate the spores from bulk soil down to a pellet that can be used for further analysis. Soil extraction solution and mechanical shaking are used to disrupt soil particle aggregates and to aid in the separation of spores from soil particles. Soil samples are washed twice with soil extraction solution to maximize recovery. Differential centrifugation is used to separate spores from the majority of the soil material. The 45 g protocol has been demonstrated by two laboratories using both loamy and sandy soil types. There were no significant differences overall between the two laboratories for either soil type, suggesting that the processing protocol would be robust enough to use at multiple laboratories while achieving comparable recoveries. The 45 g protocol has demonstrated a matrix limit of detection at 14 spores/gram of soil for loamy and sandy soils.

Effects of permafrost thaw on carbon emissions under aerobic and anaerobic environments in the Great Hing'an Mountains, China.

PubMed

Song, Changchun; Wang, Xianwei; Miao, Yuqing; Wang, Jiaoyue; Mao, Rong; Song, Yanyu

2014-07-15

The carbon (C) pool of permafrost peatland is very important for the global C cycle. Little is known about how permafrost thaw could influence C emissions in the Great Hing'an Mountains of China. Through aerobic and anaerobic incubation experiments, we studied the effects of permafrost thaw on CH4 and CO2 emissions. The rates of CH4 and CO2 emissions were measured at -10, 0 and 10°C. Although there were still C emissions below 0°C, rates of CH4 and CO2 emissions significantly increased with permafrost thaw under aerobic and anaerobic conditions. The C release under aerobic conditions was greater than under anaerobic conditions, suggesting that permafrost thaw and resulting soil environment change should be important influences on C emissions. However, CH4 stored in permafrost soils could affect accurate estimation of CH4 emissions from microbial degradation. Calculated Q10 values in the permafrost soils were significantly higher than values in active-layer soils under aerobic conditions. Our results highlight that permafrost soils have greater potential decomposability than soils of the active layer, and such carbon decomposition would be more responsive to the aerobic environment. © 2013 Elsevier B.V. All rights reserved.

Defense.gov Special Report: Superstorm Sandy

Science.gov Websites

Guard Members Provide Post-Sandy Aid Guardsmen Send Supplies to Stricken Communities Marines Assist New Response Army Engineers 'Forward Leaning' in Response Department Continues Post-Hurricane Sandy Support Virginia, D.C. Guard Members Provide Post-storm Aid DOD Provides Hurricane Sandy Response Update President

Spatial distribution of Eucalyptus roots in a deep sandy soil in the Congo: relationships with the ability of the stand to take up water and nutrients.

PubMed

Laclau, J P; Arnaud, M; Bouillet, J P; Ranger, J

2001-02-01

Spatial statistical analyses were performed to describe root distribution and changes in soil strength in a mature clonal plantation of Eucalyptus spp. in the Congo. The objective was to analyze spatial variability in root distribution. Relationships between root distribution, soil strength and the water and nutrient uptake by the stand were also investigated. We studied three, 2.35-m-wide, vertical soil profiles perpendicular to the planting row and at various distances from a representative tree. The soil profiles were divided into 25-cm2 grid cells and the number of roots in each of three diameter classes counted in each grid cell. Two profiles were 2-m deep and the third profile was 5-m deep. There was both vertical and horizontal anisotropy in the distribution of fine roots in the three profiles, with root density decreasing sharply with depth and increasing with distance from the stump. Roots were present in areas with high soil strength values (> 6,000 kPa). There was a close relationship between soil water content and soil strength in this sandy soil. Soil strength increased during the dry season mainly because of water uptake by fine roots. There were large areas with low root density, even in the topsoil. Below a depth of 3 m, fine roots were spatially concentrated and most of the soil volume was not explored by roots. This suggests the presence of drainage channels, resulting from the severe hydrophobicity of the upper soil.

Incorporated Woodchips as a Novel Intervention to Support Plant Growth through Increased Water Holding Capacity and Nutrient Retention in Sandy Degraded Soils

NASA Astrophysics Data System (ADS)

Menzies, E.; Schneider, R.; Walter, T.

2017-12-01

According to the World Wildlife Federation's most recent Plow Print report 53 million acres of temperate, water limited, grasslands across the Great Plains have been converted to agriculture since 2009. This conversion very often begins the process of soil degradation which can lead to desertification and the necessity to convert more land to agriculture. The most common solution to this problem is improved crop efficiency to reduce conversion of grasslands to agriculture while still producing enough food for us all. We suggest that while that may be the beginning of the solution, degraded soils need to be rehabilitated and brought back into production to adequately provide food crops for the increasing population of the globe. Incorporated woodchips can be used to improve the soils' water holding capacity and nutrient (N and P) retention. In a previous study we observed an increase in the gravimetric water content and a decrease in soluble N and P losses when fertilizers were applied in liquid form in soil columns with incorporated woodchips (see attached figure). In this study we examine the availability of the retained water and nutrients to grasses to determine the extent to which this intervention might be used to reestablish plant growth in degraded sandy soils. We also begin examining the quantity of woodchips necessary to retain sufficient water and nutrients to sustain the growth of grasses over the course of a growing season. A laboratory soil column study is currently underway to examine these questions; the results of this study will be presented at the Fall Meeting.

Deep Compaction Control of Sandy Soils

NASA Astrophysics Data System (ADS)

Bałachowski, Lech; Kurek, Norbert

2015-02-01

Vibroflotation, vibratory compaction, micro-blasting or heavy tamping are typical improvement methods for the cohesionless deposits of high thickness. The complex mechanism of deep soil compaction is related to void ratio decrease with grain rearrangements, lateral stress increase, prestressing effect of certain number of load cycles, water pressure dissipation, aging and other effects. Calibration chamber based interpretation of CPTU/DMT can be used to take into account vertical and horizontal stress and void ratio effects. Some examples of interpretation of soundings in pre-treated and compacted sands are given. Some acceptance criteria for compaction control are discussed. The improvement factors are analysed including the normalised approach based on the soil behaviour type index.

Microbial transformation of 8:2 fluorotelomer acrylate and methacrylate in aerobic soils.

PubMed

Royer, Laurel A; Lee, Linda S; Russell, Mark H; Nies, Loring F; Turco, Ronald F

2015-06-01

Biotransformation of fluorotelomer (FT) compounds, such as 8:2 FT alcohol (FTOH) is now recognized to be a source of perfluorooctanoic acid (PFOA) as well as other perfluoroalkyl acids. In this study, microbially mediated hydrolysis of FT industrial intermediates 8:2 FT acrylate (8:2 FTAC) and 8:2 FT methacrylate (8:2 FTMAC) was evaluated in aerobic soils for up to 105d. At designated times, triplicate microcosms were sacrificed by sampling the headspace for volatile FTOHs followed by sequential extraction of soil for the parent monomers as well as transient and terminal degradation products. Both FTAC and FTMAC were hydrolyzed at the ester linkage as evidenced by 8:2 FTOH production. 8:2 FTAC and FTMAC degraded rapidly with half-lives ⩽5d and 15d, respectively. Maximum 8:2 FTOH levels were 6-13mol% within 3-6d. Consistent with the known biotransformation pathway of 8:2 FTOH, FT carboxylic acids and perfluoroalkyl carboxylic acids were subsequently generated including up to 10.3mol% of PFOA (105d). A total mass balance (parent plus metabolites) of 50-75mol% was observed on the last sampling day. 7:2 sFTOH, a direct precursor to PFOA, unexpectedly increased throughout the incubation period. The likely, but unconfirmed, concomitant production of acrylic acids was proposed as altering expected degradation patterns. Biotransformation of 8:2 FTAC, 8:2 FTMAC, and previously reported 8:2 FT-stearate for the same soils revealed the effect of the non-fluorinated terminus group linked to the FT chain on the electronic differences that affect microbially-mediated ester cleavage rates. Copyright © 2014 Elsevier Ltd. All rights reserved.

Spatial Patterns and Natural Recruitment of Native Shrubs in a Semi-arid Sandy Land

PubMed Central

Wu, Bo; Yang, Hongxiao

2013-01-01

Passive restoration depending on native shrubs is an attractive approach for restoring desertified landscapes in semi-arid sandy regions. We sought to understand the relationships between spatial patterns of native shrubs and their survival ability in sandy environments. Furthermore, we applied our results to better understand whether passive restoration is feasible for desertified landscapes in semi-arid sandy regions. The study was conducted in the semi-arid Mu Us sandy land of northern China with the native shrub Artemisia ordosica. We analyzed population structures and patterns of A. ordosica at the edges and centers of land patches where sand was stabilized by A. ordosica-dominated vegetation. Saplings were more aggregated than adults, and both were more aggregated at the patch edges than at the patch centers. At the patch edges, spatial association of the saplings with the adults was mostly positive at distances 0.3–6.6 m, and turned from positive to neutral, and even negative, at other distances. At the patch centers, the saplings were spaced almost randomly around the adults, and their distances from the adults did not seem to affect their locations. A greater number of A. ordosica individuals emerged at the patch edges than at the patch centers. Such patterns may have resulted from their integrative adjustment to specific conditions of soil water supply and sand drift intensity. These findings suggest that in semi-arid sandy regions, native shrubs that are well-adapted to local environments may serve as low-cost and competent ecological engineers that can promote the passive restoration of surrounding patches of mobile sandy land. PMID:23505489

Microbial community structure of sandy intertidal sediments in the North Sea, Sylt-Rømø Basin, Wadden Sea.

PubMed

Musat, Niculina; Werner, Ursula; Knittel, Katrin; Kolb, Steffen; Dodenhof, Tanja; van Beusekom, Justus E E; de Beer, Dirk; Dubilier, Nicole; Amann, Rudolf

2006-06-01

Molecular biological methods were used to investigate the microbial diversity and community structure in intertidal sandy sediments near the island of Sylt (Wadden Sea) at a site which was characterized for transport and mineralization rates in a parallel study (D. de Beer, F. Wenzhöfer, T. Ferdelman, S.E. Boehme, M. Huettel, J.E.E. van Beusekom, M.E. Böttcher, N. Musat, N. Dubilier, Transport and mineralization rates in North Sea sandy intertidal sediments, Sylt-Romo Basin, Wadden Sea, Limnol. Oceanogr. 50 (2005) 113-127). Comparative 16S rRNA sequence analysis revealed a high bacterial diversity. Most sequences retrieved by PCR with a general bacterial primer set were affiliated with Bacteroidetes, Gammaproteobacteria, Deltaproteobacteria and the Pirellula cluster of Planctomycetales. Fluorescence in situ hybridization (FISH) and slot-blot hybridization with group-specific rRNA-targeted oligonucleotide probes were used to characterize the microbial community structure over depth (0-12 cm) and seasons (March, July, October). We found high abundances of bacteria with total cell numbers up to 3 x 10(9) cells ml(-1) and a clear seasonal variation, with higher values in July and October versus March. The microbial community was dominated by members of the Planctomycetes, the Cytophaga/Flavobacterium group, Gammaproteobacteria, and bacteria of the Desulfosarcina/Desulfococcus group. The high abundance (1.5 x 10(7)-1.8 x 10(8) cells ml(-1) accounting for 3-19% of all cells) of presumably aerobic heterotrophic polymer-degrading planctomycetes is in line with the high permeability, deep oxygen penetration, and the high rates of aerobic mineralization of algal biomass measured in the sandy sediments by de Beer et al. (2005). The high and stable abundance of members of the Desulfosarcina/Desulfococcus group, both over depth and season, suggests that these bacteria may play a more important role than previously assumed based on low sulfate reduction rates in parallel cores

Kinetic analysis of aerobic biotransformation pathways of a perfluorooctane sulfonate (PFOS) precursor in distinctly different soils.

PubMed

Zhang, Lilan; Lee, Linda S; Niu, Junfeng; Liu, Jinxia

2017-10-01

With the phaseout of perfluorooctane sulfonate (PFOS) production in most countries and its well known recalcitrance, there is a need to quantify the potential release of PFOS from precursors previously or currently being emitted into the environment. Aerobic biodegradation of N-ethyl perfluorooctane sulfonamidoethanol (EtFOSE) was monitored in two soils from Indiana, USA: an acidic forest silt loam (FRST-48, pH = 5.5) and a high pH agricultural loam (PSF-49, pH = 7.8) with similar organic carbon contents (2.4 and 2.6%) for 210 d and 180 d, respectively. At designated times, triplicate samples were sacrificed for which headspace samples were taken followed by three sequential extractions. Extracts were analyzed using HPLC-tandem mass spectrometry. Measured profiles of EtFOSE degradation and generation/degradation of subsequent metabolites were fitted to the Indiana soils data as well as to a previously published data set for a Canadian soil using an R-based model (KinGUII) to explore pathways and estimate half-lives (t 1/2 ) for EtFOSE and metabolites. EtFOSE degradation ranged from a few days to up to a month. PFOS yields ranged form 1.06-5.49 mol% with the alkaline soils being four to five times higher than the acidic soil. In addition, a direct pathway to PFOS had to be invoked to describe the early generation of PFOS in the Canadian soil. Of all metabolites, the sulfonamidoacetic acids were the most persistent (t 1/2  ≥ 3 months) in all soils. We hypothesized that while pH-pK a dependent speciation may have impacted rates, differences in microbial communities between the 3 soils arising from varied soil properties including pH, nutrient levels, soil management, and climatic regions are likely the major factors affecting pathways, rates, and PFOS yields. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sorption and mobility of metronidazole, olaquindox, oxytetracycline and tylosin in soil.

PubMed

Rabølle, M; Spliid, N H

2000-04-01

Laboratory studies were conducted to characterise four different antibiotic compounds with regard to sorption and mobility in various soil types. Distribution coefficients (Kd values) determined by a batch equilibrium method varied between 0.5 and 0.7 for metronidazole, 0.7 and 1.7 for olaquindox and 8 and 128 for tylosin. Tylosin sorption seems to correlate positively with the soil clay content. No other significant interactions between soil characteristics and sorption were observed. Oxytetracycline was particularly strongly sorbed in all soils investigated, with Kd values between 417 in sand soil and 1026 in sandy loam, and no significant desorption was observed. Soil column leaching experiments indicated large differences in the mobility of the four antibiotic substances, corresponding to their respective sorption capabilities. For the weakly adsorbed substances metronidazole and olaquindox the total amounts added were recovered in the leachate of both sandy loam and sand soils. For the strongly adsorbed oxytetracyline and tylosin nothing was detected in the leachate of any of the soil types, indicating a much lower mobility. Results from defractionation and extraction of the columns (30 cm length) showed that 60-80% of the tylosin added had been leached to a depth of 5 cm in the sandy loam soil and 25 cm in the sand soil.

Cumulative effects of sewage sludge and effluent mixture application on soil properties of a sandy soil under a mixture of star and kikuyu grasses in Zimbabwe

NASA Astrophysics Data System (ADS)

Madyiwa, S.; Chimbari, M.; Nyamangara, J.; Bangira, C.

Although sewage effluent and sludge provides nutrients for plant growth, its continual use over extended periods can result in the accumulation of heavy metals in soils and in grass to levels that are detrimental to the food chain. This study was carried in 2001 out at Firle farm, owned by the Municipality of Harare, to assess heavy metal loading on a sandy soil and uptake of the metals by pasture grass consisting of a mixture of Cynodon nlemfuensis (star grass) and Pennisetum clandestinum Chiov (kikuyu grass) following sewage effluent and sludge application for 29 years. Firle Farm receives treated effluent and sludge emanating from domestic and industrial sources. Soil and grass samples were taken from the study area, consisting of 3 ha of non-irrigated area (control) and 1.3 ha of irrigated area. Both the soil and grass samples were tested for Cu, Zn, Ni and Pb using atomic absorption spectrophotometry. Sewage sludge addition resulted in high levels of soil pollution, especially in the 20 cm horizon, in the irrigated area when compared to the control. Grasses took up moderate levels of Cu and Zn, and limited levels of Pb. Nickel was not detectable in grasses despite high levels in the irrigated soil. Copper uptake was several times higher than the suggested potentially toxic level of 12 mg/kg [Soil Science Society of America, Micronutrients in agriculture, second ed., Wisconsin, USA, 1991]. Lead uptake averaged 1.0 mg/kg, which was below 10 mg/kg the suggested limit for agronomic crops [E.M. Seaker, Zinc, copper, cadmium and lead in minespoil, water and plants from reclaimed mine land amended with sewage sludge, 1991]. Cu and Zn showed relatively higher mobility down the soil profile than Ni and Pb. Even then, the concentrations in the lower soil layers were very small, suggesting that the metals were unlikely to contaminate groundwater. There was no direct correlation between metal levels in soils and grasses. It was postulated that it is the bio

[Ecological distribution and antimicrobial effects of soil actinomycetes in artificial vegetation systems in Shazhuyu of Qinghai, China].

PubMed

Yang, Bin; Xue, Quan-hong; Chen, Zhan-quan; Guo, Zhi-ying; Zhang, Xiao-lu; Zhou, Yong-qiang; Xu, Ying-jun; Sun, De-fu

2008-08-01

In order to probe into the effects of artificial vegetation rehabilitation on soil actinomycetes, dilution plate and agar block methods were used to investigate the ecological distribution and antimicrobial effects of actinomycetes in sandy soil in Shazhuyu area of Qinghai after artificial vegetation restoration. The results showed that with the vegetation rehabilitation and the improvement of vegetation coverage on alpine sandy dry land, the quantity of soil actinomycetes increased significantly, being 145.4% higher in the grassland transferred from farmland than in sandy land. The quantity of soil Micromonospora in grassland transferred from farmland was about six times as much as that in sandy land. The average selection rate of antimicrobial actinomycetes was increased greatly, with the antimicrobial actinomycetes in the soil of grassland transferred from farmland, the antibacterial actinomycetes in the soil of natural grassland, and the pathogenic fungus resistant aetinomycetes in the soil of forestland being approximately 2, 3.2 and 1.5 times as much as those in the soil of sandy land, respectively. Vegetation coverage and soil nutrients had great influences on the quantities of actinomycetes and antimicrobial actinomycetes. The contents of soil organic matter and alkali-hydrolyzable nitrogen and the yield of fresh grasses had significant correlations with the quantities of actinomycetes (P < 0.01), and the content of soil organic matter and the yield of fresh grasses significantly correlated with the strain numbers of antimicrobial actinomycetes (P < 0.01). Furthermore, vegetation coverage and the contents of soil total nitrogen, total phosphorous, total potassium, total salt, and available potassium had significant correlations with the total quantities of actinomycetes, Streptomycetes, and Micromonospora (P < 0.05).

Responses of 1-year-old cottonwood to increasing soil moisture tension

Treesearch

F.T. Bonner

1967-01-01

Cottonwood cuttings planted in sandy loam and clay soils showed a sensitive control of water loss as soil moisture tension increased. Transpiration rates began decreasing at leaf water deficits of 2.5 percent in sandy loam and 4.5 percent in clay. There were no significant differences in rates per unit of leaf area or shoot dry weight between plants grown in the two...

Soil development in OSL dated sandy dune substrates under Quercus robur Forest (Netherlands)

NASA Astrophysics Data System (ADS)

van Mourik, J. M.; Nierop, Ir. K.; Verstraten, J. M.

2009-04-01

Coastal dune landscapes are very dynamic. The present distribution of vegetation and soil is the result of over 2000 years of natural processes and human management. The initial soil development was controlled by an increase of the organic matter content, which consisted mainly of decomposed roots of grasses (rhizomull), and a decrease of the soil pH to 3-4 by decalcification. This stage was followed by the development of a deciduous forest, which was dominated by Quercus robur. Since 1600 AD, a large part of the deciduous forest that dominated the east side of the coastal dune landscape transferred in expensive residential areas and urbanizations. Nevertheless some parts of the oak forest belt remained. The present forest soils are acid and the controlling soil processes are leaching of sesquioxides and storage of organic matter in mormoder humus forms. The sustainability of ecosystems is closely related to the quality of the humus form, controlling nutrient cycling and water supply. Therefore, improve of knowledge of humus form development and properties is important. We applied soil micromorphology and pyrolysis-gas chromatography/mass spectrometry (GC/MS) to investigate more details of humus form development at two locations (Duivendrift and Hoek van Klaas) in the coastal dune area of the Amsterdamse Waterleidingduinen (near Haarlem, the Netherlands). However, to understand forest soil development, including the organic matter composition in the humus form, the age of the substrate and the forest is required. Therefore, we used tradition techniques as pollen analysis and radiocarbon dating but also the recently introduced optical stimulated luminescence (OSL) dating technique. OSL dating works excellent for aeolian sandy deposits with a high percentage of quartz grains. The OSL age is defined as the time after the last bleaching by solar radiation of mineral grains. Or in other words, the start of a stable period without sand drifting. In the Ah horizons we

Evaluation of propargyl bromide for control of barnyardgrass and Fusarium oxysporum in three soils.

PubMed

Ma, Q; Gan, J; Becker, J O; Papiernik, S K; Yates, S R

2001-09-01

With the scheduled phasing out of methyl bromide, there is an urgent need for alternatives. We evaluated the efficacy of propargyl bromide as a potential replacement for methyl bromide for the control of barnyardgrass (Echinochloa crus-galli) and Fusarium oxysporum in an Arlington sandy loam, a Carsitas loamy sand and a Florida muck soil. Soil was mixed with barnyardgrass seeds or F oxysporum colonized on millet seeds, and treated with propargyl bromide at a range of concentrations. The mortality of the fungi and weed seeds was determined after 24 h of exposure at 30 degrees C. The concentrations required to inhibit 50% barnyard seed germination (LC50) were 2.8, 2.4 and 48.5 micrograms g-1 in the sandy loam, loamy sand and muck soil, respectively. In contrast, the LC50 values for F oxysporum were 11.2, 10.8 and 182.1 micrograms g-1 in the sandy loam, loamy sand and muck soil, respectively. The low efficacy of propargyl bromide in the muck soil was a result of the rapid degradation and high adsorption of the compound in the soil. The degradation half-life (t1/2) was only 7 h in the muck soil at an initial concentration of 6.8 micrograms g-1, compared to 60 and 67 h in the sandy loam and loamy sand, respectively. The adsorption coefficients (Kd) were 0.96, 0.87 and 5.6 cm3 g-1 in the sandy loam, loamy sand and muck soil, respectively. These results suggest that registration agencies should consider site-specific properties in recommending application rates for propargyl bromide.

The determination of the real nano-scale sizes of bacteria in chernozem during microbial succession by means of hatching of a soil in aerobic and anaerobic conditions

NASA Astrophysics Data System (ADS)

Gorbacheva, M.

2012-04-01

M.A. Gorbacheva,L.M. Polyanskaya The Faculty of Soil Science, Moscow State University, Leninskie Gory, GSP-1, Moscow,119991,Russia In recent years there's been particular attention paid to the smallest life's forms- bacteria which size can be measured in nanometer. These are the forms of bacteria with diameter of 5-200 nm. Theoretical calculations based on the content of the minimum number of DNA, enzyme, lipids in and ribosome in cells indicates impossibility of existence of a living cells within diameter less than 300 nm. It is theoretically possible for a living cell to exist within possible diameter of approximately 140 nm. Using a fluorescence microscope there's been indicated in a number of samples from lakes, rivers, soil, snow and rain water that 200 nm is the smallest diameter of a living cell. Supposingly, such a small size of bacteria in soil is determined by natural conditions which limit their development by nutritious substances and stress-factors. Rejuvenescence of nanobacteria under unfavourable natural conditions and stress-factors is studied in laboratory environment. The object of the current study has become the samples of typical arable chernozem of the Central Chernozem State Biosphere Reserve in Kursk. The detailed morphological description of the soil profile and its basic analytical characteristics are widely represented in scientific publications. The soil is characterized by a high carbon content which makes up 3,96% ,3,8% , and 2,9% for the upper layers of the A horizon, and 0,79% for the layer of the B horizon. A microbial succession was studied under aerobic and anaerobic conditions by means of experiments with microcosms in upper A horizons and B horizon of a chernozem. The final aim is to identify the cells size of bacteria in aerobic and anaerobic soil conditions in chernozem during the microbial succession, by dampening and application of chitin by means of «cascade filtration» method. The study of the microcosms is important for

Interaction Among Machine Traffic, Soil Physical Properties and Loblolly Pine Root Prolifereation in a Piedmont Soil

Treesearch

Emily A. Carter; Timothy P. McDonald

1997-01-01

The impact of forwarder traffic on soil physical properties was evaluated on a Gwinnett sandy loam, a commonly found soil of the Piedmont. Soil strength and saturated hydraulic conductivity were significantly altered by forwarder traffic, but reductions in air-filled porosity also occurred. Bulk density did not increase significantly in trafficked treatments. The...

Role of macrofauna on benthic oxygen consumption in sandy sediments of a high-energy tidal beach

NASA Astrophysics Data System (ADS)

Charbonnier, Céline; Lavesque, Nicolas; Anschutz, Pierre; Bachelet, Guy; Lecroart, Pascal

2016-06-01

Sandy beaches exposed to tide and waves are characterized by low abundance and diversity of benthic macrofauna, because of high-energy conditions. This is the reason why there are few studies on benthic communities living in such highly dynamic environments. It has been shown recently that tidal sandy beaches may act as biogeochemical reactors. Marine organic matter that is supplied in the sand during each flood tide is efficiently mineralized through aerobic respiration. In order to quantify the role of macrofauna in the whole beach benthic respiration, we studied the macrofauna and the pore water oxygen content of an exposed sandy beach (Truc Vert, SW of France) during four seasons in 2011. The results showed that macrofauna was characterised by a low number of species of specialized organisms such as the crustaceans Eurydice naylori and Gastrosaccus spp. and the polychaetes Ophelia bicornis and Scolelepis squamata. The distribution and abundance of macrofauna were clearly affected by exposure degree and emersion time. The combined monitoring of benthic macrofauna and pore waters chemistry allowed us to estimate (1) the macrofauna oxygen uptake, calculated with a standard allometric relationship using biomass data, and (2) the total benthic oxygen uptake, calculated from the oxygen deficit measured in pore waters. This revealed that benthic macrofauna respiration represented a variable but low (<10%) contribution to the total benthic oxygen consumption. This suggests that oxygen was mainly consumed by microbial respiration.

Urease activity in different soils of Egypt.

PubMed

el-Shinnawi, M M

1978-01-01

Samples from two depths (0--15 and 15--30 cm) of five Egyptian soils: sandy, calcareous, fertile alluvial, saline alluvial, and alkali alluvial were tested for urease activity. Samples were treated with farmyard manure at rates of 0 and 0.5% C, and moisture at levels of 50, 65, and 80% of the water holding capacity. The studied Egyptian soils showed different activities of urease. Decreases in the values were shown by depth of sampling and varied in their intensities according to soil type, except for saline soil which revealed an opposite trend by the higher activity of its sub-surface layer. Order of activity was the following: fertile, saline, alkali, calcareous, and sandy soil. Farmyard manure slightly increased the activity of the enzyme. Incubation of moistened samples revealed that the optimum moisture content was 50% of W.H.C. for the tested soils, except for saline which showed best results at 65% of W.H.C.

Biodegradation and bioremediation potential of diazinon-degrading Serratia marcescens to remove other organophosphorus pesticides from soils.

PubMed

Cycoń, Mariusz; Żmijowska, Agnieszka; Wójcik, Marcin; Piotrowska-Seget, Zofia

2013-03-15

The ability of diazinon-degrading Serratia marcescens to remove organophosphorus pesticides (OPPs), i.e. chlorpyrifos (CP), fenitrothion (FT), and parathion (PT) was studied in a mineral salt medium (MSM) and in three soils of different characteristics. This strain was capable of using all insecticides at concentration of 50 mg/l as the only carbon source when grown in MSM, and 58.9%, 70.5%, and 82.5% of the initial dosage of CP, FT, and PT, respectively was degraded within 14 days. The biodegradation experiment showed that autochthonous microflora in all soils was characterized by a degradation potential of all tested OPPs; however, the initial lag phases for degradation of CP and FT, especially in sandy soil, were observed. During the 42-day experiment, 45.3%, 61.4% and 72.5% of the initial dose of CP, FT, and PT, respectively, was removed in sandy soil whereas the degradation of CP, FT, and PT in the same period, in sandy loam and silty soils reached 61.4%, 79.7% and 64.2%, and 68.9%, 81.0% and 63.6%, respectively. S. marcescens introduced into sterile soils showed a higher degradation potential (5-13%) for OPPs removal than those observed in non-sterile soil with naturally occurring attenuation. Inoculation of non-sterile soils with S. marcescens enhanced the disappearance rates of all insecticides, and DT50 for CP, FT, and PT was reduced by 20.7, 11.3 and 13.0 days, and 11.9, 7.0 and 8.1 days, and 9.7, 14.5 and 12.6 days in sandy, sandy loam, and silty soils, respectively, in comparison with non-sterile soils with only indigenous microflora. This ability of S. marcescens makes it a suitable strain for bioremediation of soils contaminated with OPPs. Copyright © 2013 Elsevier Ltd. All rights reserved.

MEASUREMENTS OF INFILTRATION RATES IN COMPACTED URBAN SOILS

EPA Science Inventory

Previous research hs identified significant reductions in infiltration rates in disturbed urban soils, More than 150 prior tests were conducted in predominately sandy and clayey urban soils in the Birmingham and Mobile, AL areas. Infiltration in Clayey soils ws found to be affect...

The Effects of Soil Texture on the Ability of Human Remains Detection Dogs to Detect Buried Human Remains.

PubMed

Alexander, Michael B; Hodges, Theresa K; Wescott, Daniel J; Aitkenhead-Peterson, Jacqueline A

2016-05-01

Despite technological advances, human remains detection (HRD) dogs still remain one of the best tools for locating clandestine graves. However, soil texture may affect the escape of decomposition gases and therefore the effectiveness of HDR dogs. Six nationally credentialed HRD dogs (three HRD only and three cross-trained) were evaluated on novel buried human remains in contrasting soils, a clayey and a sandy soil. Search time and accuracy were compared for the clayey soil and sandy soil to assess odor location difficulty. Sandy soil (p < 0.001) yielded significantly faster trained response times, but no significant differences were found in performance accuracy between soil textures or training method. Results indicate soil texture may be significant factor in odor detection difficulty. Prior knowledge of soil texture and moisture may be useful for search management and planning. Appropriate adjustments to search segment sizes, sweep widths and search time allotment depending on soil texture may optimize successful detection. © 2016 American Academy of Forensic Sciences.

Soil suitability for hardwoods in Coastal Plains

Treesearch

W. M. Broadfoot; J. S. McKnight

1962-01-01

The Coastal Plain soil area occupies the major portion of Mississippi east of the Delta and Loess areas. In general, the soils are sandy, acid, and lacking in natural fertility, but on the alluvial soils moisture and drainage relations appear sufficient to support good growth of some tree species.

Development of an extraction method for perchlorate in soils.

PubMed

Cañas, Jaclyn E; Patel, Rashila; Tian, Kang; Anderson, Todd A

2006-03-01

Perchlorate originates as a contaminant in the environment from its use in solid rocket fuels and munitions. The current US EPA methods for perchlorate determination via ion chromatography using conductivity detection do not include recommendations for the extraction of perchlorate from soil. This study evaluated and identified appropriate conditions for the extraction of perchlorate from clay loam, loamy sand, and sandy soils. Based on the results of this evaluation, soils should be extracted in a dry, ground (mortar and pestle) state with Milli-Q water in a 1 ratio 1 soil ratio water ratio and diluted no more than 5-fold before analysis. When sandy soils were extracted in this manner, the calculated method detection limit was 3.5 microg kg(-1). The findings of this study have aided in the establishment of a standardized extraction method for perchlorate in soil.

Degradation kinetics of ptaquiloside in soil and soil solution.

PubMed

Ovesen, Rikke Gleerup; Rasmussen, Lars Holm; Hansen, Hans Christian Bruun

2008-02-01

Ptaquiloside (PTA) is a carcinogenic norsesquiterpene glycoside produced in bracken (Pteridium aquilinum (L.) Kuhn), a widespread, aggressive weed. Transfer of PTA to soil and soil solution eventually may contaminate groundwater and surface water. Degradation rates of PTA were quantified in soil and soil solutions in sandy and clayey soils subjected to high natural PTA loads from bracken stands. Degradation kinetics in moist soil could be fitted with the sum of a fast and a slow first-order reaction; the fast reaction contributed 20 to 50% of the total degradation of PTA. The fast reaction was similar in all horizons, with the rate constant k(1F) ranging between 0.23 and 1.5/h. The slow degradation, with the rate constant k(1S) ranging between 0.00067 and 0.029/ h, was more than twice as fast in topsoils compared to subsoils, which is attributable to higher microbial activity in topsoils. Experiments with sterile controls confirmed that nonmicrobial degradation processes constituted more than 90% of the fast degradation and 50% of the slow degradation. The lower nonmicrobial degradation rate observed in the clayey compared with the sandy soil is attributed to a stabilizing effect of PTA by clay silicates. Ptaquiloside appeared to be stable in all soil solutions, in which no degradation was observed within a period of 28 d, in strong contrast to previous studies of hydrolysis rates in artificial aqueous electrolytes. The present study predicts that the risk of PTA leaching is controlled mainly by the residence time of pore water in soil, soil microbial activity, and content of organic matter and clay silicates.

[Effects of different vegetation restoration patterns on the diversity of soil nitrogen-fixing microbes in Hulunbeier sandy land, Inner Mongolia of North China].

PubMed

Li, Gang; Wang, Li-Juan; Li, Yu-Jie; Qiao, Jiang; Zhang, Hai-Fang; Song, Xiao-Long; Yang, Dian-Lin

2013-06-01

By using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and sequence analysis, this paper studied the nifH gene diversity and community structure of soil nitrogen-fixing microbes in Hulunbeier sandy land of Inner Mongolia under four years management of five vegetation restoration modes, i. e., mixed-planting of Agropyron cristatum, Hedysarum fruticosum, Caragana korshinskii, and Elymus nutans (ACHE) and of Agropyron cristatum and Hedysarum fruticosum (AC), and mono-planting of Caragana korshinskii (UC), Agropyron cristatum (UA), and Hedysarum fruticosum (UH), taking the bare land as the control (CK). There existed significant differences in the community composition of nitrogen-fixing microbes among the five vegetation restoration patterns. The Shannon index of the nifH gene was the highest under ACHE, followed by under AC, UC, UA, and UH, and the lowest in CK. Except that UH and CK had less difference in the Shannon index, the other four vegetation restoration modes had a significantly higher Shannon index than CK (P < 0.05). The phylogenetic analysis showed that the soil nitrogen-fixing microbes under UA, UH, and UC were mainly of cyanobacteria, but the soil nitrogen-fixing microbes under AC and ACHE changed obviously, mainly of proteobacteria, and also of cyanobacteria. The canonical correlation analysis showed that the soil total phosphorus, available phosphorus, total nitrogen, and nitrate nitrogen contents under the five vegetation restoration modes had significant effects on the nitrogen-fixing microbial communities, and there existed significant correlations among the soil total phosphorus, available phosphorus, total nitrogen, and nitrate nitrogen. It was suggested that the variations of the community composition of soil nitrogen-fixing microbes under the five vegetation restoration modes were resulted from the interactive and combined effects of the soil physical and chemical factors.

Field-measured, hourly soil water evaporation stages in relation to reference evapotranspiration rate and soil to air temperature ratio

USDA-ARS?s Scientific Manuscript database

Soil water evaporation takes critical water supplies away from crops, especially in areas where both rainfall and irrigation water are limited. This study measured bare soil water evaporation from clay loam, silt loam, sandy loam, and fine sand soils. It found that on average almost half of the ir...

The Topic Is Sandy Hook: A Program for Gifted and Talented Students at Sandy Hook.

ERIC Educational Resources Information Center

Grant, David

"The Topic Is Sandy Hook" is an experiential 10-week program designed to provide special opportunities and educational experiences for 6th to 10th grade gifted and talented students. Sandy Hook, a natural resource in Monmouth County, New Jersey, is unique in its physical and historical features and provides an exceptionally rich environment in…

Soil moisture-soil temperature interrelationships on a sandy-loam soil exposed to full sunlight

Treesearch

David A. Marquis

1967-01-01

In a study of birch regeneration in New Hampshire, soil moisture and temperature were found to be intimately related. Not only does low moisture lead to high temperature, but high temperature undoubtedly accelerates soil drying, setting up a vicious cycle of heating and drying that may prevent seed germination or kill seedlings.

Improvement in the water retention characteristics of sandy loam soil using a newly synthesized poly(acrylamide-co-acrylic acid)/AlZnFe2O4 superabsorbent hydrogel nanocomposite material.

PubMed

Shahid, Shaukat Ali; Qidwai, Ansar Ahmad; Anwar, Farooq; Ullah, Inam; Rashid, Umer

2012-08-03

The use of some novel and efficient crop nutrient-based superabsorbent hydrogel nanocomposites (SHNCs), is currently becoming increasingly important to improve the crop yield and productivity, due to their water retention properties. In the present study a poly(Acrylamide-co-acrylic acid)/AlZnFe2O4 superabsorbent hydrogel nanocomposite was synthesized and its physical properties characterized using Energy Dispersive X-ray (EDX), FE-SEM and FTIR spectroscopic techniques. The effects of different levels of SHNC were studied to evaluate the moisture retention properties of sandy loam soil (sand 59%, silt 21%, clay 19%, pH 7.4, EC 1.92 dS/m). The soil amendment with 0.1, 0.2, 0.3 and 0.4 w/w% of SHNC enhanced the moisture retention significantly at field capacity compared to the untreated soil. Besides, in a separate experiment, seed germination and seedling growth of wheat was found to be notably improved with the application of SHNC. A delay in wilting of seedlings by 5-8 days was observed for SHNC-amended soil, thereby improving wheat plant growth and establishment.

Kinetics of biotransformation of chlorpyrifos in aqueous and soil slurry environments.

PubMed

Tiwari, Manoj K; Guha, Saumyen

2014-03-15

The attenuation of chlorpyrifos (CPF) by the enriched indigenous soil microorganism was studied in 15 d aerobic and 60 d anaerobic batch experiments in aqueous and soil slurry (1:3 w/w) media. At the end of the batch experiments, 2.78 ± 0.11 μM of CPF was degraded by 82% in aerobic and 66% in anaerobic aqueous environments, while 12.4 ± 0.5 μM of CPF was degraded by 48% in aerobic and 31% in anaerobic soil slurries. The reduced degradation in the soil slurries was due to the significantly (2-10 times) slower rate of degradation of soil phase CPF compared with its degradation rate in water. The pathways of degradation of CPF were identified, including a partial anaerobic degradation pathway that is constructed for the first time. The simulation of the various conversions in the degradation pathways using first order kinetics was used to analyze relative persistence of metabolites. The common metabolite 3,5,6-trichloro-2-pyridinol (TCP) accumulated (increased monotonically during the period of experiments) in aerobic soil slurry and in anaerobic aqueous as well as soil slurry systems but did not accumulate in aerobic aqueous system. The most toxic compound in the pathway, chlorpyrifos oxon (CPFO) was not detected in anaerobic environment. In aerobic environment, CPFO was short lived in aqueous medium, but accumulated slowly in the soils. Copyright © 2013 Elsevier Ltd. All rights reserved.

Impact of treated wastewater on growth, respiration and hydraulic conductivity of citrus root systems in light and heavy soils.

PubMed

Paudel, Indira; Cohen, Shabtai; Shaviv, Avi; Bar-Tal, Asher; Bernstein, Nirit; Heuer, Bruria; Ephrath, Jhonathan

2016-06-01

Roots interact with soil properties and irrigation water quality leading to changes in root growth, structure and function. We studied these interactions in an orchard and in lysimeters with clay and sandy loam soils. Minirhizotron imaging and manual sampling showed that root growth was three times lower in the clay relative to sandy loam soil. Treated wastewater (TWW) led to a large reduction in root growth with clay (45-55%) but not with sandy loam soil (<20%). Treated wastewater increased salt uptake, membrane leakage and proline content, and decreased root viability, carbohydrate content and osmotic potentials in the fine roots, especially in clay. These results provide evidence that TWW challenges and damages the root system. The phenology and physiology of root orders were studied in lysimeters. Soil type influenced diameter, specific root area, tissue density and cortex area similarly in all root orders, while TWW influenced these only in clay soil. Respiration rates were similar in both soils, and root hydraulic conductivity was severely reduced in clay soil. Treated wastewater increased respiration rate and reduced hydraulic conductivity of all root orders in clay but only of the lower root orders in sandy loam soil. Loss of hydraulic conductivity increased with root order in clay and clay irrigated with TWW. Respiration and hydraulic properties of all root orders were significantly affected by sodium-amended TWW in sandy loam soil. These changes in root order morphology, anatomy, physiology and hydraulic properties indicate rapid and major modifications of root systems in response to differences in soil type and water quality. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Using Biochar composts for improving sandy vineyard soils while reducing the risk of

NASA Astrophysics Data System (ADS)

Kammann, Claudia; Mengel, Jonathan; Mohr, Julia; Muskat, Stefan; Schmidt, Hans-Peter; Löhnertz, Otmar

2016-04-01

In recent years, biochar has increasingly been discussed as an option for sustainable environmentalmanagement, combining C sequestration with the aim of soil fertility improvement. Biochar has shownpositive effects in viticulture before (Genesio et al. 2015) which were largely attributed to improved water supply to the plants. However, in fertile temperate soils, the use of pure, untreated biochar does not guarantee economic benefits on the farm level (Ruysschaert et al., 2016). Hence, recent approaches started introducing biochar in management of nutrient-rich agricultural waste, e.g. in compost production (Kammann et al. 2015). Compost is frequently used in German vineyards for humus buildup and as a slow-release organic fertilizer. This, and increasingly mild, precipitation-rich winters, promoting mineralization, increase the risk of unwanted nitrate leaching losses into surface and ground waters during winter. To investigate if biochar pure, or biochar-compost mixtures and -products may have the potential to reduce nitrate leaching, we set up the following experiment: Either 30 or 60 t ha-1 of the following additives were mixed into the top 30 cm of sandy soil in large (120 L) containers, and planted with oneRiesling grapevine (Clone 198-30 GM) per container: Control (no addition), pure woody biochar, pure compost, biochar-compost (produced from the same organic feedstock than the compost, with 20 vol. - % of a woody biochar added), and pure compost plus pure biochar (same mixing ratio as in the former product). Once monthly, containers were exposed to simulated heavy rainfall that caused drainage. Leachates were collected from an outlet at the bottom of the containers, and analyzed for nutrients. The nutrient-rich additives containing compost all improved grape biomass and yield, most markedly pure compost and biochar-compost; same amendments were not significantly different. However,while the addition of the lower amount (30 t ha-1) of compost reduced nitrate

Sorption of thiabendazole in sub-tropical Brazilian soils.

PubMed

de Oliveira Neto, Odilon França; Arenas, Alejandro Yopasa; Fostier, Anne Hélène

2017-07-01

Thiabendazole (TBZ) is an ionizable anthelmintic agent that belongs to the class of benzimidazoles. It is widely used in veterinary medicine and as a fungicide in agriculture. Sorption and desorption are important processes influencing transport, transformation, and bioavailability of xenobiotic compounds in soils; data related to sorption capacity are therefore needed for environmental risk assessments. The aim of this work was to assess the sorption potential of TBZ in four Brazilians soils (sandy, sandy-clay, and clay soils), using batch equilibrium experiments at three pH ranges (2.3-3.0, 3.8-4.2, and 5.5-5.7). The Freundlich sorption coefficient (K F ) ranged from 9.0 to 58 μg 1-1/n  (mL) 1/n  g -1 , with higher values generally observed at the lower pH ranges (2.3-3.0 and 3.8-4.2) and for clay soils. The highest organic carbon-normalized sorption coefficients (K OC ) obtained at pH 3.8-5.7 (around the natural pH range of 4.1-5.0) for both clay soils and sandy-clay soil were 3255 and 2015 mL g -1 , respectively. The highest correlations K F vs SOM (r = 0.70) and K F vs clay content (r = 0.91) were observed at pH 3.8-4.2. Our results suggest that TBZ sorption/desorption is strongly pH dependent and that its mobility could be higher in the studied soils than previously reported in soils from temperate regions.

Retardation of iron-cyanide complexes in the soil of a former manufactured gas plant site.

PubMed

Sut, Magdalena; Repmann, Frank; Raab, Thomas

2015-01-01

The soil in the vicinities of former Manufactured Gas Plant (MGP) sites is commonly contaminated with iron-cyanide complexes (ferric ferrocyanide). The phenomenon of cyanide mobility in soil, according to the literature, is mainly governed by the dissolution and precipitation of ferric ferrocyanide, which is only slightly soluble (<1 mg L(-1)) under acidic conditions. In this paper, retention properties of the sandy loam soil and the potential vertical movement of the solid iron-cyanide complexes, co-existing with the dissolution, sorption and precipitation reactions were investigated. Preliminary research conducted on a former MGP site implied colloidal transport of ferric ferricyanide from the initial deposition in the wastes layer towards the sandy loam material (secondary accumulation), which possibly retarded the mobility of cyanide (CN). A series of batch and column experiments were applied in order to investigate the retardation of iron-cyanide complexes by the sandy loam soil. Batch experiments revealed that in circumneutral pH conditions sandy loam material decreases the potassium ferro- and ferricyanide concentration. In column experiments a minor reduction in CN concentration was observed prior to addition of iron sulfide (FeS) layer, which induced the formation of the Prussian blue colloids in circumneutral pH conditions. Precipitated solid iron-cyanide complexes were mechanically filtered by the coherent structure of the investigated soil. Additionally, the reduction of the CN concentration of the percolation solutions by the sandy loam soil was presumably induced due to the formation of potassium manganese iron-cyanide (K2Mn[Fe(CN)6]).

Stump sprouting of northern pin oak on nutrient-poor sandy soils in central Wisconsin

Treesearch

Kevin M. Schwartz; Michael C. Demchik

2013-01-01

Coppice with two to three reserve trees per acre is the generally accepted practice (GAP) for rotating oak stands on nutrient-poor, sandy sites (colloquially called "scrub oak sites") in Wisconsin. The future stocking of the stand is therefore dependent predominantly on stump sprouts with varying levels of contribution from advance regeneration. Two groups of...

[Introduction of upland rice cultivars to eastern Keerqin sandy land and their biological characteristics].

PubMed

Zeng, Dehui; Zhang, Chunxing; Wang, Guirong; Fan, Zhiping

2004-10-01

Developing water-saving rice cultivation is one important strategy for food security in China. This paper reported the experimental results of introducing six upland rice cultivars to eastern Keerqin sandy land. The field experiment results showed that under the condition of 60% water-saving, the yield of cultivars XH 95-13 and XH 95-13-6 was 10.2% and 5.5% higher than the control, respectively, while other four cultivars decreased by 6.7%-18.6%. Economically, all the cultivars except JP 121 had a higher income than the control, and the profitability of cultivars XH 95-13 and XH 95-13-6 reached 24.0% and 19.3%, respectively. The water productivity of all the six cultivars was over 0.566 kg x m(-3), increased by 59.89%-116.38%. Pot experiment showed that 12.1%-16.3% of soil moisture in 0-15 cm layer was beneficial to the growth of upland rice. In eastern Keerqin sandy land, effective tillers occurred before July 18. In brief, upland rice production could be extensively applicable in eastern Keerqin sandy land to gradually alternate the traditional lowland rice cultivation with continuous flooding, and save much underground water.

Dynamic chemical characteristics of soil solution after pig manure application: a column study.

PubMed

Hao, Xiuzhen; Zhou, Dongmei; Sun, Lei; Li, Lianzhen; Zhang, Hailin

2008-06-01

When manures from intensive livestock operations are applied to agricultural or vegetable fields at a high rate, large amounts of salts and metals will be introduced into soils. Using a column leaching experiment, this study assessed the leaching potential of the downward movement of Cu and Zn as well as some salt ions after an intensive farm pig manure at rates of 0%, 5% and 10% (w/w) were applied to the top 20 cm of two different textured soils (G soil -sandy loam soil; H soil-silty clay loam soil), and investigated the growth of amaranth and Cu and Zn transfer from soil to amaranth (Amaranthus tricolor). Soil solutions were obtained at 20, 40 and 60 cm depth of the packed column and analyzed for pH, electrical conductivity (EC), dissolved organic matter (DOC) and Cu and Zn concentrations. The results indicated that application of pig manure containing Cu and Zn to sandy loam soil might cause higher leaching and uptake risk than silty clay loam soil, especially at high application rates. And manure amendment at 5% and 10% significantly decreased the biomass of amaranth, in which the salt impact rather than Cu and Zn toxicity from manures played more important role in amaranth growth. Thus the farmer should avoid application the high rate of pig manure containing metal and salt to soil at a time, especially in sandy soil.

Emerging organic pollutants in the vadose zone of a soil aquifer treatment system: Pore water extraction using positive displacement.

PubMed

Sopilniak, Alexander; Elkayam, Roy; Rossin, Anna Voloshenko; Lev, Ovadia

2018-01-01

Trace organic compounds in effluents, water streams and aquifers are amply reported. However, the mobile pool of Emerging Organic Contaminants (EOCs) in the deep parts of the vadose zone is hard to estimate, due to difficulties in extraction of sufficient quantity of pore water. Here, we present a new methodology for depth profiling of EOCs in pore water by Positive Displacement Extraction (PDE): Pore water extraction from unsaturated soil samples is carried out by withdrawal of soil cores by direct-push drilling and infiltrating the core by organics free water. We show that EOC concentrations in the water eluted in the plateau region of the inverse breakthrough curve is equal to their pore water concentrations. The method was previously validated for DOC extraction, and here the scope of the methodology is extended to pore water extraction for organic pollutants analysis. Method characteristics and validation were carried out with atrazine, simazine, carbamazepine, venlafaxine, O-desmethylvenlafaxine and caffeine in the concentration range of several ng to several μg/liter. Validation was carried out by laboratory experiments on three different soils (sandy, sandy-clayey and clayey). Field studies in the vadose zone of a SAT system provided 27 m deep EOC profiles with less than 1.5 m spatial resolution. During the percolation treatment, carbamazepine remained persistent, while the other studied EOCs were attenuated to the extent of 50-99%.The highest degradation rate of all studied EOCs was in the aerobic zone. EOC levels based on PDE and extraction by centrifugation were compared, showing a positive bias for centrifugation. Copyright © 2017 Elsevier Ltd. All rights reserved.

The mathematical model accuracy estimation of the oil storage tank foundation soil moistening

NASA Astrophysics Data System (ADS)

Gildebrandt, M. I.; Ivanov, R. N.; Gruzin, AV; Antropova, L. B.; Kononov, S. A.

2018-04-01

The oil storage tanks foundations preparation technologies improvement is the relevant objective which achievement will make possible to reduce the material costs and spent time for the foundation preparing while providing the required operational reliability. The laboratory research revealed the nature of sandy soil layer watering with a given amount of water. The obtained data made possible developing the sandy soil layer moistening mathematical model. The performed estimation of the oil storage tank foundation soil moistening mathematical model accuracy showed the experimental and theoretical results acceptable convergence.

NOAA releases final report of Sandy service assessment

Science.gov Websites

released a report on the National Weather Service's performance during hurricane/post tropical cyclone Sandy. The report, Hurricane/Post Tropical Cyclone Sandy Service Assessment, reaffirms that the National warnings for dangerous storms like Sandy, even when they are expected to become post-tropical cyclones by

Decreasing Nitrogen Fertilizer Input Had Little Effect on Microbial Communities in Three Types of Soils

PubMed Central

Yu, Hailing; Gao, Qiang; Shao, Zeqiang; Ying, Anning; Sun, Yuyang; Liu, Jingwei; Mao, Wei; Zhang, Bin

2016-01-01

In this study, we examined the influence of different nitrogen (N) application rates (0, 168, 240, 270 and 312 kg N ha-1) on soil properties, maize (Zea mays L.) yields and microbial communities of three types of soils (clay, alluvial and sandy soils). Phospholipid fatty acid analysis was used to characterize soil microbial communities. Results indicated that N fertilization significantly decreased microbial biomass in both clay and sandy soils regardless of application rate. These decreases were more likely a result of soil pH decreases induced by N fertilization, especially in the sandy soils. This is supported by structural equation modeling and redundancy analysis results. Nitrogen fertilization also led to significant changes in soil microbial community composition. However, the change differences were gradually dismissed with increase in N application rate. We also observed that N fertilization increased maize yields to the same level regardless of application rate. This suggests that farmers could apply N fertilizers at a lower rate (i.e. 168 kg N ha-1), which could achieve high maize yield on one hand while maintain soil microbial functions on the other hand. PMID:26992097

Selenite reduction by the obligate aerobic bacterium Comamonas testosteroni S44 isolated from a metal-contaminated soil

PubMed Central

2014-01-01

Background Selenium (Se) is an essential trace element in most organisms but has to be carefully handled since there is a thin line between beneficial and toxic concentrations. Many bacteria have the ability to reduce selenite (Se(IV)) and (or) selenate (Se(VI)) to red elemental selenium that is less toxic. Results A strictly aerobic bacterium, Comamonas testosteroni S44, previously isolated from metal(loid)-contaminated soil in southern China, reduced Se(IV) to red selenium nanoparticles (SeNPs) with sizes ranging from 100 to 200 nm. Both energy dispersive X-ray Spectroscopy (EDX or EDS) and EDS Elemental Mapping showed no element Se and SeNPs were produced inside cells whereas Se(IV) was reduced to red-colored selenium in the cytoplasmic fraction in presence of NADPH. Tungstate inhibited Se(VI) but not Se(IV) reduction, indicating the Se(IV)-reducing determinant does not contain molybdenum as co-factor. Strain S44 was resistant to multiple heavy and transition metal(loid)s such as Se(IV), As(III), Cu(II), and Cd(II) with minimal inhibitory concentrations (MIC) of 100 mM, 20 mM, 4 mM, and 0.5 mM, respectively. Disruption of iscR encoding a transcriptional regulator negatively impacted cellular growth and subsequent resistance to multiple heavy metal(loid)s. Conclusions C. testosteroni S44 could be very useful for bioremediation in heavy metal(loid) polluted soils due to the ability to both reduce toxic Se(VI) and Se(IV) to non-toxic Se (0) under aerobic conditions and to tolerate multiple heavy and transition metals. IscR appears to be an activator to regulate genes involved in resistance to heavy or transition metal(loid)s but not for genes responsible for Se(IV) reduction. PMID:25098921

[Effects of litter and root exclusion on soil microbial community composition and function of four plantations in subtropical sandy coastal plain area, China].

PubMed

Sang, Chang Peng; Wan, Xiao Hua; Yu, Zai Peng; Wang, Min Huang; Lin, Yu; Huang, Zhi Qun

2017-04-18

We conducted detritus input and removal treatment (DIRT) to examine the effects of shifting above- and belowground carbon (C) inputs on soil microbial biomass, community composition and function in subtropical Pinus elliottii, Eucalyptus urophylla × Eucalyptus grandis, Acacia aulacocarpa and Casuarina equisetifolia coastal sandy plain forests, and the treatments included: root trenching, litter removal and control. Up to September 2015, one year after the experiment began, we collected the 0-10 cm soil samples from each plot. Phospholipid fatty acid (PLFA) analysis was used to characterize the microbial community composition, and micro-hole enzymatic detection technology was utilized to determine the activity of six kinds of soil enzymes. Results showed that changes in microbial biomass induced by the C input manipulations differed among tree species, and mainly affected by litter and root qualily. In E. urophylla × E. grandis stands, root trenching significantly decreased the contents of total PLFAs, Gram-positive bacteria, Gram-negative bacteria, fungi and actinomycetes by 31%, 30%, 32%, 36% and 26%, respectively. Litter removal reduced the contents of Gram-positive bacteria, fungi and actinomycetes by 24%, 27% and 24%, respectively. However, C input manipulations had no significant effect on soil microbial biomassunder other three plantations. According to the effect of C input manipulations on soil microbial community structure, litter and root exclusion decreased fungi abundance and increased actinomycetes abundance. Different treatments under different plantations resulted in various soil enzyme activities. Litter removal significantly decreased the activities of cellobiohydrolase, β-glucosidase, acid phosphatase and N-acetyl-β-d-glucosaminidase of P. elliottii, A. aulacocarpa and C. equisetifolia, root exclusion only decreased and increased the activities of β-glucosidase in P. elliottii and A. aulacocarpa forest soils, respectively. Litter removal also

Degradation of TCE using sequential anaerobic biofilm and aerobic immobilized bed reactor

NASA Technical Reports Server (NTRS)

Chapatwala, Kirit D.; Babu, G. R. V.; Baresi, Larry; Trunzo, Richard M.

1995-01-01

Bacteria capable of degrading trichloroethylene (TCE) were isolated from contaminated wastewaters and soil sites. The aerobic cultures were identified as Pseudomonas aeruginosa (four species) and Pseudomonas fluorescens. The optimal conditions for the growth of aerobic cultures were determined. The minimal inhibitory concentration values of TCE for Pseudomonas sps. were also determined. The aerobic cells were immobilized in calcium alginate in the form of beads. Degradation of TCE by the anaerobic and dichloroethylene (DCE) by aerobic cultures was studied using dual reactors - anaerobic biofilm and aerobic immobilized bed reactor. The minimal mineral salt (MMS) medium saturated with TCE was pumped at the rate of 1 ml per hour into the anaerobic reactor. The MMS medium saturated with DCE and supplemented with xylenes and toluene (3 ppm each) was pumped at the rate of 1 ml per hour into the fluidized air-uplift-type reactor containing the immobilized aerobic cells. The concentrations of TCE and DCE and the metabolites formed during their degradation by the anaerobic and aerobic cultures were monitored by GC. The preliminary study suggests that the anaerobic and aerobic cultures of our isolates can degrade TCE and DCE.

The effect of soil type on the bioremediation of petroleum contaminated soils.

PubMed

Haghollahi, Ali; Fazaelipoor, Mohammad Hassan; Schaffie, Mahin

2016-09-15

In this research the bioremediation of four different types of contaminated soils was monitored as a function of time and moisture content. The soils were categorized as sandy soil containing 100% sand (type I), clay soil containing more than 95% clay (type II), coarse grained soil containing 68% gravel and 32% sand (type III), and coarse grained with high clay content containing 40% gravel, 20% sand, and 40% clay (type IV). The initially clean soils were contaminated with gasoil to the concentration of 100 g/kg, and left on the floor for the evaporation of light hydrocarbons. A full factorial experimental design with soil type (four levels), and moisture content (10 and 20%) as the factors was employed. The soils were inoculated with petroleum degrading microorganisms. Soil samples were taken on days 90, 180, and 270, and the residual total petroleum hydrocarbon (TPH) was extracted using soxhlet apparatus. The moisture content of the soils was kept almost constant during the process by intermittent addition of water. The results showed that the efficiency of bioremediation was affected significantly by the soil type (Pvalue < 0.05). The removal percentage was the highest (70%) for the sandy soil with the initial TPH content of 69.62 g/kg, and the lowest for the clay soil (23.5%) with the initial TPH content of 69.70 g/kg. The effect of moisture content on bioremediation was not statistically significant for the investigated levels. The removal percentage in the clay soil was improved to 57% (within a month) in a separate experiment by more frequent mixing of the soil, indicating low availability of oxygen as a reason for low degradation of hydrocarbons in the clay soil. Copyright © 2016 Elsevier Ltd. All rights reserved.

Kinetics of diuron under aerobic condition and residue analysis in sugarcane under subtropical field conditions.

PubMed

Tandon, Shishir; Pant, Ravi

2017-10-10

The phenylureas group includes persistent herbicides which are major pollutants to soil and water. Dissipation kinetics of diuron in different soils under sugarcane field conditions was investigated. Diuron was extracted with acetone and florisil solid phase extraction clean-up and characterized by high-performance liquid chromatography-UV. Diuron persisted for more than 100 days and dissipation followed monophasic first-order kinetics. Persistence was more in sandy loam compared to silty clay loam soil. Half-life of diuron in silty clay loam soil was 22.57 and 32.37 days and in sandy loam was 28.35 and 43.93 days at 2 and 4 kg ha-1applications, respectively. Average recovery in soil, bagasse, leaf-straw and juice ranged from 75.95% to 84.20%, 80.15% to 89.35%, 77.46% to 86.19% and 81.88% to 92.68%, respectively. The quantitation limits for soil, bagasse, leaf-straw and juice were 0.01, 0.03, 0.04 μg g -1 and 0.008 μg mL -1 , respectively. Application of diuron inhibited growth of soil microbes initially but they recovered later. At harvest, diuron residues were below maximum residue limits in all samples. The study revealed that under subtropical conditions, diuron is safe for use in weed management and would not pose any residual/environmental problem and that sugarcane crop could be used safe for human/animal consumption.

Fates of nickel and fluoranthene during the bioremediation by Pleurotus eryngii in three different soils.

PubMed

Tang, Xia; Dong, Shunwen; Shi, Wenjin; Gao, Ni; Zuo, Lei; Xu, Heng

2016-11-01

This study focused on the bioremediation role of Pleurotus eryngii in different characteristics soils contaminated with nickel (Ni) and fluoranthene. The results of bioremediation experiments showed that fluoranthene had a positive effect on the growth of P. eryngii, whereas Ni exerted a negative influence. The concentration of fluoranthene significantly decreased in inoculated soil accounting for 86.39-91.95% of initial concentration in soils and 71.46-81.76% in non-inoculated soils, which showed that the dissipation of fluoranthene was enhanced by mushroom inoculating. The highest removal rates of fluoranthene in sandy loam, loamy clay, and sandy soils reached to 87.81, 86.39, and 91.95%, respectively, which demonstrated that P. eryngii was more suitable for the bioremediation of sandy soil contaminated with fluoranthene. In addition, the presence of Ni tended to decrease the dissipation of fluoranthene in inoculated soil. Higher ligninolytic enzymes activities were detected in inoculated soils, resulting in the enhanced dissipation of fluoranthene in inoculated soils. Furthermore, P. eryngii had the ability to uptake Ni (4.88-39.53 mg kg -1 ) in co-contamination soil. In conclusion, the inoculating of P. eryngii was effective in remediating of Ni-fluoranthene co-contaminated soils. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of red mud on soil microbial communities: Application and comprehensive evaluation of the Biolog EcoPlate approach as a tool in soil microbiological studies.

PubMed

Feigl, Viktória; Ujaczki, Éva; Vaszita, Emese; Molnár, Mónika

2017-10-01

Red mud can be applied as soil ameliorant to acidic, sandy and micronutrient deficient soils. There are still knowledge gaps regarding the effects of red mud on the soil microbial community. The Biolog EcoPlate technique is a promising tool for community level physiological profiling. This study presents a detailed evaluation of Biolog EcoPlate data from two case studies. In experiment "A" red mud from Ajka (Hungary) was mixed into acidic sandy soil in soil microcosms at 5-50 w/w%. In experiement "B" red mud soil mixture was mixed into low quality subsoil in a field experiment at 5-50 w/w%. According to average well color development, substrate average well color development and substrate richness 5-20% red mud increased the microbial activity of the acidic sandy soil over the short term, but the effect did not last for 10months. Shannon diversity index showed that red mud at up to 20% did not change microbial diversity over the short term, but the diversity decreased by the 10th month. 30-50% red mud had deteriorating effect on the soil microflora. 5-20% red mud soil mixture in the low quality subsoil had a long lasting enhancing effect on the microbial community based on all Biolog EcoPlate parameters. However, 50% red mud soil mixture caused a decrease in diversity and substrate richness. With the Biolog EcoPlate we were able to monitor the changes of the microbial community in red mud affected soils and to assess the amount of red mud and red mud soil mixture applicable for soil treatment in these cases. Copyright © 2017 Elsevier B.V. All rights reserved.

Occurrence and Fate of Trace Contaminants during Aerobic and Anaerobic Sludge Digestion and Dewatering.

PubMed

Guerra, Paula; Kleywegt, Sonya; Payne, Michael; Svoboda, M Lewina; Lee, Hing-Biu; Reiner, Eric; Kolic, Terry; Metcalfe, Chris; Smyth, Shirley Anne

2015-07-01

Digestion of municipal wastewater biosolids is a necessary prerequisite to their beneficial use in land application, in order to protect public health and the receiving environment. In this study, 13 pharmaceuticals and personal care products (PPCPs), 11 musks, and 17 polybrominated diphenyl ethers were analyzed in 84 samples including primary sludge, waste activated sludge, digested biosolids, dewatered biosolids, and dewatering centrate or filtrate collected from five wastewater treatment plants with aerobic or anaerobic digestion. Aerobic digestion processes were sampled during both warm and cold temperatures to analyze seasonal differences. Among the studied compounds, triclosan, triclocarban, galaxolide, and BDE-209 were the substances most frequently detected under different treatment processes at levels up to 30,000 ng/g dry weight. Comparing aerobic and anaerobic digestion, it was observed that the levels of certain PPCPs and musks were significantly higher in anaerobically digested biosolids, relative to the residues from aerobic digestion. Therefore, aerobic digestion has the potential advantage of reducing levels of PPCPs and musks. On the other hand, anaerobic digestion has the advantage of recovering energy from the biosolids in the form of combustible gases while retaining the nutrient and soil conditioning value of this resource. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

[The influence of straw, particularly rice straw, together with calcium-cyanamide on the microbiological activity of two Portuguese soils (author's transl)].

PubMed

Glathe, H; El Din, A; Scheuer, A

1976-01-01

The influence of calcium-cyanamide upon the microbiological activity was tested in pot experiments under controlled conditions in two Portuguese soils (sandy and loamy) after the addition of rice or wheat straw (rice straw 0.275% N, wheat straw 0.307% N). The amount of straw was equalled to 100 dz/ha, the application of calcium-cyanamide to 25, 50 and 100 kg N/ha. In the containers treated with straw the total amount of microorganisms (Koch-method) was higher in sandy than in loamy soil after 30 days, but after 70 days it was higher in loamy soil. The content of active nitrogen (NH4 + NO3) increased, when calcium-cyanamide was added, but decreased after the application of straw. After 70 days sandy soil again showed an increase of active nitrogen. Straw increased the rates of CO2-production considerably, wheat straw was superior to rice straw. Calcium-cyanamide increased the CO2-production more in sandy than in loamy soil or German loess, which was also used for this experiment. Only in the case of rice straw higher doses of calcium-cyanamide had a positive effect. After 70 days the CO2-production rose only when rice straw was applied. The dehydrogenase-activity was increased in both soils, but a superiority of wheat straw occurred in sandy soil only. The microbiological activity in the pots with straw was higher in sandy than in loamy soil, the addition of calcium-cyanamide accelerated it. Doses of 25-50 kg N/ha are sufficient generally. The period of the formation of insoluble organic N-compounds, usually connected with the application of organic matter with a wide N:C-ratio, seems to be reduced by the addition of calcium-cyanamide.

[Influence of a new phosphoramide urease inhibitor on urea-N transformation in different texture soil].

PubMed

Zhou, Xuan; Wu, Liang Huan; Dai, Feng

2016-12-01

Addition of urease inhibitors is one of the important measures to increase nitrogen (N) use efficiency of crop, due to retardant of urea hydrolysis and reduction of ammonia volatilization loss. An incubation experiment was conducted to investigate the urease inhibition effect of a new phosphoramide urease inhibitor, NPPT (N-(n-propyl) thiophosphoric triamide) in different texture soils under dark condition at 25 ℃, and NBPT (N-(n-butyl) thiophosphoric triamide) was obtained to compare the inhibition effect on urease in different soil textures by different dosages of urea adding. Results showed that the effective reaction time of urea was less than 9 d in the loamy and clay soil. Addition of inhibitors for retardation of urea hydrolysis was more than 3 d. In sandy soil, urea decomposition was relatively slow, and adding inhibitor significantly inhibited soil urease acti-vity, and reduced NH 4 + -N content. During the incubation time, the inhibition effect of high dosage urea in the soil was better than that of low dosage. At day 6, the urease inhibition rate of NBPT and NPPT (N 250 mg·kg -1 ) were 56.3% and 53.0% in sandy soil, 0.04% and 0.3% in loamy soil, 4.1% and 6.2% in clay soil; the urease inhibition rate of NBPT and NPPT (N 500 mg·kg -1 ) were 59.4% and 65.8% in sandy soil, 14.5% and 15.1% in loamy soil, 49.1% and 48.1% in clay soil. The urease inhibition effects in different texture soil were in order of sandy soil > clay soil> loamy soil. The soil NH 4 + -N content by different inhibitors during incubation time increased at first and then decreased, while soil NO 3 - -N content and apparent nitrification rate both showed rising trends. Compared with urea treatment, addition of urease inhibitors (NBPT and NPPT) significantly increased urea-N left in the soil and reduced NH 4 + -N content. In short, new urease inhibitor NPPT in different texture is an effective urease inhibitor.

Soil Nitrification and N2O Production: the connection with N concentration and Soil Water Content

NASA Astrophysics Data System (ADS)

Zhu-Barker, X.; Horwath, W. R.

2016-12-01

The development of mitigation strategies to reduce nitrous oxide (N2O) emission from soils is dependent on explicating the biophysical factors affecting different N2O production pathways. Ammonia oxidation and heterotrophic denitrification are the main pathways of N2O production, depending on soil conditions such as soil moisture content, oxygen (O2) content and N substrate. Many researchers have reported that N2O production increased as substrate concentration and soil moisture content increased. However, less understood is how N fertilizer concentration and moisture content interact to affect N2O production pathways. To investigate interaction and its effect on O2 consumption, we incubated three agricultural soils (clay, sandy loam, and peat) with different concentrations of (NH4)2SO4 (0-1000 µg N g-1) under 50 %, 75%, and 100% of water holding capacity. All treatments received 15N -KNO3 to bring the concentrations of NO3-_N in soils to 50 mg kg-1 soil and the NO3- pool to an enrichment of 10 atom% 15N. In all soils, the total amount of O2 consumption and N2O production increased as soil ammonical N concentration increased. The increased soil moisture significantly promoted N2O production in sandy loam and clay loam soils, compared to the peat soil. These results indicate that N2O production increased as substrate concentration increased likely due to the onset of O2 limitation caused by ammonia oxidation.

Mobilization of phenol and dichlorophenol in unsaturated soils by non-uniform electrokinetics.

PubMed

Luo, Qishi; Zhang, Xihui; Wang, Hui; Qian, Yi

2005-06-01

The poor mobility of organic pollutants in contaminated sites frequently results in slow remediation processes. Organics, especially hydrophobic compounds, are generally retained strongly in soil matrix as a result of sorption, sequestration, or even formation into non-aqueous-phase liquids and their mobility is thus greatly reduced. The objective of this study was to evaluate the feasibility of using non-uniform electrokinetic transport processes to enhance the mobility of organic pollutants in unsaturated soils with no injection reagents. Phenol and 2,4-dichlorophenol (2,4-DCP), and kaolin and a natural sandy loam soil were selected as model organics and soils, respectively. The results showed that non-uniform electrokinetics can accelerate the desorption and movement of phenol and 2,4-DCP in unsaturated soils. Electromigration and electroosmotic flow were the main driving forces, and their role in the mobilization of phenol and 2,4-DCP varied with soil pH. The movement of 2,4-DCP in the sandy loam towards the anode (about 1.0 cmd(-1)V(-1)) was 1.0-1.5 cmd(-1)V(-1) slower than that in the kaolin soil, but about 0.5 cmd(-1)V(-1) greater than that of phenol in the sandy loam. When the sandy loam was adjusted to pH 9.3, the movement of phenol and 2,4-DCP towards the anode was about twice and five times faster than that at pH 7.7, respectively. The results also demonstrated that the movement of phenol and 2,4-DCP in soils can be easily controlled by regulating the operational mode of electric field. It is believed that non-uniform electrokinetics has the potential for practical application to in situ remediation of organics-contaminated sites.

Study on reinforcement of soil for suppressing fugitive dust by bio-cementitious material

NASA Astrophysics Data System (ADS)

Zhan, Qiwei; Qian, Chunxiang

2017-06-01

Microbial-induced reinforcement of soil, as a new green and environmental-friendly method, is being paid extensive attention to in that it has low cost, simple operation and rapid effects. In this research, reinforcement of soil for suppressing fugitive dust by bio-cementitious material was investigated. Soil cemented by bio-cementitious material had superior mechanical properties, such as hardness, compressive strength, microstructure, wind-erosion resistance, rainfall-erosion resistance and freeze-thaw resistance. The average hardness of sandy soil, floury soil and clay soil is 18.9 º, 25.2 º and 26.1 º, while average compressive strength of samples is 0.43 MPa, 0.54 MPa and 0.69 MPa, respectively; meanwhile, the average calcite content of samples is 6.85 %, 6.09 %, and 5.96 %, respectively. Compared with the original sandy soil, floury soil and clay soil, the porosity decreases by 38.5 %, 33.7 % and 29.2 %. When wind speed is 12 m/s, the mass loss of sandy soil, floury soil and clay soil cemented by bio-cementitious material are all less than 30 g/(m2·h). After three cycles of rainfall erosion of 2.5 mm/h, the mass loss are less than 25 g/(m2·h) and the compressive strength residual ratio are more than 98.0 %. Under 25 cycles of freeze-thaw, the mass loss ratio are less than 3.0 %.

Relationships between Soil and Levels of Meloidogyne incognita and Tobacco Yield and Quality.

PubMed

Barker, K R; Weeks, W W

1991-01-01

A 2-year study with six soils and four levels of Meloidogyne incognita in microplots was designed to determine the effects of these parameters on nematode activity and tobacco yield and quality. Key components under study were affected by soil, nematode level, and season (year-cultivar). In 1980, low initial nematode numbers (1,250) enhanced tobacco yield in Cecil clay loam, but caused slight to moderate yield losses in the other soils. Yield losses to M. incognita were generally greatest in sandy and muck soils. In 1980, regression analyses of the independent parameters Pi - clay-sand vs. yield gave an R(2) of 0.40. Examples of other coefficients of determination for yield vs. selected factors were root-necrosis index, 0.40; root-gall index, 0.18; root-gall index-cation exchange capacity (CEC), 0.34; root-necrosis index-CEC, 0.56; and root-necrosis index-sand-soil acidity-calcium, 0.62. In contrast, the R(2) for Pi alone versus yield in 1981 was 0.84. Soil also affected nematode reproduction with the greatest increases occurring in the sandy soils. In both years, low nematode numbers enhanced the synthesis of sugar in tobacco, whereas leaves from all other nematode treatments had low sugar levels. A low nicotine content was associated with nematode infection. Tobacco from sandy soils had a higher nicotine content than tobacco from clay soils.

Manure-amended soil characteristics affecting the survival of E. coli O157:H7 in 36 Dutch soils.

PubMed

Franz, Eelco; Semenov, Alexander V; Termorshuizen, Aad J; de Vos, O J; Bokhorst, Jan G; van Bruggen, Ariena H C

2008-02-01

The recent increase in foodborne disease associated with the consumption of fresh vegetables stresses the importance of the development of intervention strategies that minimize the risk of preharvest contamination. To identify risk factors for Escherichia coli O157:H7 persistence in soil, we studied the survival of a Shiga-toxin-deficient mutant in a set of 36 Dutch arable manure-amended soils (organic/conventional, sand/loam) and measured an array of biotic and abiotic manure-amended soil characteristics. The Weibull model, which is the cumulative form of the underlying distribution of individual inactivation kinetics, proved to be a suitable model for describing the decline of E. coli O157:H7. The survival curves generally showed a concave curvature, indicating changes in biological stress over time. The calculated time to reach the detection limit ttd ranged from 54 to 105 days, and the variability followed a logistic distribution. Due to large variation among soils of each management type, no differences were observed between organic and conventional soils. Although the initial decline was faster in sandy soils, no significant differences were observed in ttd between both sandy and loamy soils. With sandy, loamy and conventional soils, the variation in ttd was best explained by the level of dissolved organic carbon per unit biomass carbon DOC/biomC, with prolonged survival at increasing DOC/biomC. With organic soils, the variation in ttd was best explained by the level of dissolved organic nitrogen (positive relation) and the microbial species diversity as determined by denaturing gradient gel electrophoresis (negative relation). Survival increased with a field history of low-quality manure (artificial fertilizer and slurry) compared with high-quality manure application (farmyard manure and compost). We conclude that E. coli O157:H7 populations decline faster under more oligotrophic soil conditions, which can be achieved by the use of organic fertilizer with a

Aflatoxin decomposition in various soils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Angle, J.S.

The persistence of aflatoxin in the soil environment could potentially result in a number of adverse environmental consequences. To determine the persistence of aflatoxin in soil, /sup 14/C-labeled aflatoxin B1, was added to silt loam, sandy loam, and silty clay loam soils and the subsequent release of /sup 14/CO/sub 2/ was determined. After 120 days of incubation, 8.1% of the original aflatoxin added to the silt loam soil was released as CO/sub 2/. Aflatoxin decomposition in the sandy loam soil proceeded more quickly than the other two soils for the first 20 days of incubation. After this time, the decompositionmore » rate declined and by the end of the study, 4.9% of the aflatoxin was released as CO/sub 2/. Aflatoxin decomposition proceeded most slowly in the silty clay loam soil. Only 1.4% of aflatoxin added to the soil was released as CO/sub 2/ after 120 days incubation. To determine whether aflatoxin was bound to the silty clay loam soil, aflatoxin B1 was added to this soil and incubated for 20 days. The soil was periodically extracted and the aflatoxin species present were determined using thin layer chromatographic (TLC) procedures. After one day of incubation, the degradation products, aflatoxins B2 and G2, were observed. It was also found that much of the aflatoxin extracted from the soil was not mobile with the TLC solvent system used. This indicated that a conjugate may have formed and thus may be responsible for the lack of aflatoxin decomposition.« less

Evaluating the environmental parameters that determine aerobic biodegradation half-lives of pesticides in soil with a multivariable approach.

PubMed

Wang, Yuxin; Lai, Adelene; Latino, Diogo; Fenner, Kathrin; Helbling, Damian E

2018-06-14

Aerobic biodegradation half-lives (half-lives) are key parameters used to evaluate pesticide persistence in soil. However, half-life estimates for individual pesticides often span several orders of magnitude, reflecting the impact that various environmental or experimental parameters have on half-lives in soil. In this work, we collected literature-reported half-lives for eleven pesticides along with associated metadata describing the environmental or experimental conditions under which they were derived. We then developed a multivariable framework to discover relationships between the half-lives and associated metadata. We first compared data for the herbicide atrazine collected from 95 laboratory and 65 field studies. We discovered that atrazine application history and soil texture were the parameters that have the largest influence on the observed half-lives in both types of studies. We then extended the analysis to include ten additional pesticides with data collected exclusively from laboratory studies. We found that, when data were available, pesticide application history and biomass concentrations were always positively associated with half-lives. The relevance of other parameters varied among the pesticides, but in some cases the variability could be explained by the physicochemical properties of the pesticides. For example, we found that the relative significance of the organic carbon content of soil for determining half-lives depends on the relative solubility of the pesticide. Altogether, our analyses highlight the reciprocal influence of both environmental parameters and intrinsic physicochemical properties for determining half-lives in soil. Copyright © 2018 Elsevier Ltd. All rights reserved.

Influence of wood-derived biochar on the physico-mechanical and chemical characteristics of agricultural soils

NASA Astrophysics Data System (ADS)

Ahmed, Ahmed S. F.; Raghavan, Vijaya

2018-01-01

Amendment of soil with biochar has been shown to enhance fertility and increase crop productivity, but the specific influence of biochar on soil workability remains unclear. Select physico-mechanical and chemical properties of clay loam and sandy loam soils were measured after amendment with wood-derived biochar of two particle size ranges (0.5-425 and 425-850 µm) at five dosages ranging from 0.5 to 10% dry weight. Whereas the clay loam soil workability decreased when the finer wood-derived biochar was applied at rates of 6 or 10%, soil fertility was not enhanced. The sandy loam soil, due to Proctor compaction, significantly decreased in bulk density with 6 and 10% wood-derived biochar amendments indicating higher soil resistance to compaction.

Soil nitrous oxide emissions after deposition of dairy cow excreta in eastern Canada.

PubMed

Rochette, Philippe; Chantigny, Martin H; Ziadi, Noura; Angers, Denis A; Bélanger, Gilles; Charbonneau, Édith; Pellerin, Doris; Liang, Chang; Bertrand, Normand

2014-05-01

Urine and dung deposited by grazing dairy cows are a major source of nitrous oxide (NO), a potent greenhouse gas that contributes to stratospheric ozone depletion. In this study, we quantified the emissions of NO after deposition of dairy cow excreta onto two grassland sites with contrasting soil types in eastern Canada. Our objectives were to determine the impact of excreta type, urine-N rate, time of the year, and soil type on annual NO emissions. Emissions were monitored on sandy loam and clay soils after spring, summer, and fall urine (5 and 10 g N patch) and dung (1.75 kg fresh weight dung) applications to perennial grasses in two successive years. The mean NO emission factor (EF) for urine was 1.09% of applied N in the clay soil and 0.31% in the sandy loam soil, estimates much smaller than the default Intergovernmental Panel on Climate Change (IPCC) default value for total excreta N (2%). Despite variations in urine composition and in climatic conditions, these soil-specific EFs were similar for the two urine-N application rates. The time of the year when urine was applied had no impact on emissions from the sandy loam soil, but greater EFs were observed after summer (1.59%) than spring (1.14%) and fall (0.55%) applications in the clay soil. Dung deposition impact on NO emission was smaller than that of urine, with a mean EF of 0.15% in the sandy loam soil and 0.08% in the clay soil. Our results suggest (i) that the IPCC default EF overestimates NO emissions from grazing cattle excreta in eastern Canada by a factor of 4.3 and (ii) that a region-specific inventory methodology should account for soil type and should use specific EFs for urine and dung. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Variation in microbial activity in histosols and its relationship to soil moisture.

PubMed

Tate, R L; Terry, R E

1980-08-01

Microbial biomass, dehydrogenase activity, carbon metabolism, and aerobic bacterial populations were examined in cropped and fallow Pahokee muck (a lithic medisaprist) of the Florida Everglades. Dehydrogenase activity was two- to sevenfold greater in soil cropped to St. Augustinegrass (Stenotaphrum secundatum (Walt) Kuntz) compared with uncropped soil, whereas biomass ranged from equivalence in the two soils to a threefold stimulation in the cropped soil. Biomass in soil cropped to sugarcane (Saccharum spp. L) approximated that from the grass field, whereas dehydrogenase activities of the cane soil were nearly equivalent to those of the fallow soil. Microbial biomass, dehydrogenase activity, aerobic bacterial populations, and salicylate oxidation rates all correlated with soil moisture levels. These data indicate that within the moisture ranges detected in the surface soils, increased moisture stimulated microbial activity, whereas within the soil profile where moisture ranges reached saturation, increased moisture inhibited aerobic activities and stimulated anaerobic processes.

Testing Associations of Plant Functional Diversity with Carbon and Nitrogen Storage along a Restoration Gradient of Sandy Grassland

PubMed Central

Zuo, Xiaoan; Zhou, Xin; Lv, Peng; Zhao, Xueyong; Zhang, Jing; Wang, Shaokun; Yue, Xiyuan

2016-01-01

The trait-based approach shows that ecosystem function is strongly affected by plant functional diversity as reflected by the traits of the most abundant species (community-weighted mean, CWM) and functional dispersion (FDis). Effects of CWM and FDis individually support the biomass ratio hypothesis and the niche complementarity hypothesis. However, there is little empirical evidence on the relative roles of CWM traits and FDis in explaining the carbon (C) and nitrogen (N) storage in grassland ecosystems. We measured plant functional traits in the 34 most abundant species across 24 sites along a restoration gradient of sandy grassland (mobile dune, semi-fixed dune, fixed dune, and grassland) in Horqin Sand Land, northern China. Thereafter, we calculated the CWM traits, the functional divergence of each single trait (FDvar) and the trait dispersion of multiple traits (FDis). We also measured the C and N storage in plant, litter, root, and soil. Using a stepwise multiple regression analysis, we further assessed which of the functional diversity components best explained C and N storage in the sandy grassland restoration. We found consistent links between C or N storage and leaf traits related to plant resource use strategy. However, the CWM of plant height was retained as an important predictor of C and N storage in plant, litter, soil, and total ecosystem in the final multiple models. CWMs of specific leaf area and plant height best predicted soil C and N storage and total ecosystem N storage. FDis was one of good predictors of litter C and N storage as well as total ecosystem C storage. These results suggest that ecosystem C and N pools in the sandy grassland restoration are primarily associated with the traits of the most abundant species in communities, thereby supporting the biomass ratio hypothesis. The positive associations of FDis with C storage in litter and total ecosystem provide evidence to support the niche complementarity hypothesis. Both functional

15N-CPMAS nuclear magnetic resonace spectroscopy and biological stability of soil organic nitrogen in whole soil and particle-size fractions

Treesearch

R.J. DiCosty; D.P. Weliky; S.J. Anderson; E.A. Paul

2003-01-01

Soil organic nitrogen was quantified by solid-state 15N cross-polarization nuclear magnetic resonance spectroscopy (NMR) during a 14-month laboratory incubation of a sandy loam soil amended with 15N-clover. In whole soil and particle-size fractions, the clover-derived N was always 85-90% amide, 5 10% guanidinium N of...

Cadmium dynamics in soil pore water and uptake by rice: Influences of soil-applied selenite with different water managements.

PubMed

Wan, Yanan; Camara, Aboubacar Younoussa; Yu, Yao; Wang, Qi; Guo, Tianliang; Zhu, Lina; Li, Huafen

2018-05-11

Cadmium (Cd) in rice grains is a potential threat to human health. This study investigated the effects of selenite fertilisation (0 mg kg -1 , 0.5 mg kg -1 , and 1.0 mg kg -1 ) on soil solution Cd dynamics and rice uptake. Rice was grown in two Cd-contaminated soils in Jiangxi and Hunan Provinces under two different sets of conditions: aerobic and flooded. The experiments were conducted in pots. The plants were harvested at the seedling stage and at maturity to determine their Cd levels. Soil solutions were also extracted during the growing season to monitor Cd dynamics. The results showed that in the Jiangxi soil (pH 5.25), Cd concentrations in the soil solutions, seedlings, and mature rice plants were higher under aerobic than under flooded water management conditions. In the Hunan soil (pH 7.26), however, flooding decreased Cd levels in the rice seedlings but not in mature plants. Selenite additions to the Hunan soil decreased Cd concentrations in the soil solutions and in the mature rice plants. These effects were not observed for the solutions or the plants from Jiangxi soil amended with selenite. Relative to the control treatment, 0.5 mg kg -1 selenite decreased the rice grain Cd content by 45.2% and 67.7% under aerobic and flooding conditions, respectively. The results demonstrated that water management regimes affected rice Cd uptake more effectively in Jiangxi than in Hunan soil, whereas selenite addition was more effective in Hunan than in Jiangxi soil. Selenite addition was also more effective at reducing rice grain Cd levels when it was applied under flooding than under aerobic conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Influence of soil types and osmotic pressure on growth and 137Cs accumulation in blackgram (Vigna mungo L.).

PubMed

Win, Khin Thuzar; Oo, Aung Zaw; Bellingrath-Kimura, Sonoko Dorothea

2017-04-01

A pot experiment was conducted to study the effects of soil types and osmotic levels on growth and 137 Cs accumulation in two blackgram varieties differing in salinity tolerance grown in Fukushima contaminated soils. The contamination levels of the sandy clay loam and clay soil were 1084 and 2046 Bq kg -1 DW, respectively. The 137 Cs activity was higher in both plants grown on the sandy clay loam than on the clay soil regardless of soil 137 Cs activity concentration. No significant differences were observed in all measured growth parameters between the two varieties under optimal water conditions for both types of soil. However, the growth, leaf water contents and 137 Cs activity concentrations in both plants were lower in both soil types when there was water stress induced by addition of polyethylene glycol. Water stress-induced reduction in total leaf area and total biomass, in addition to leaf relative water content, were higher in salt sensitive 'Mut Pe Khaing To' than in salt tolerant 'U-Taung-2' plants for both soil types. Varietal difference in decreased 137 Cs uptake under water stress was statically significant in the sandy clay loam soil, however, it was not in the clay soil. The transfer of 137 Cs from soil to plants (i.e., root, stem and leaf) was higher for the sandy clay loam for both plants when compared with those of the clay soil. The decreased activity of 137 Cs in the above ground samples (leaf and stem) in both plants in response to osmotic stress suggested that plant available 137 Cs decreased when soil water is limited by osmotic stress. Copyright © 2017 Elsevier Ltd. All rights reserved.

Temperature effect on mineralization of SOM, plant litter and priming: modified by soil type?

NASA Astrophysics Data System (ADS)

Azzaroli Bleken, Marina; Berland Frøseth, Randi

2015-04-01

The purpose of this study was to provide improved temperature response functions to be used in models of soil organic carbon (SOC) and litter mineralization, with focus on the winter period. Our working hypothesis were: 1) decomposition of SOM and plant residue occurs also at temperature close to the freezing point; 2) the effect of temperature on SOC decomposition is stronger in clayey than in sandy soil; 3) decomposition and response to temperature of added plant litter is not affected by soil type. A silty clay loam (27% clay, 3% sand) and a sandy loam (6% clay, 51% sand) with similar weather and cultivation history were pre-incubated at about 15° C for about 4.5 months. Clover leaves labelled with 13C were added to half of the samples, and soil with and without clover was incubated for 142 days at 0, 4, 8.5 or 15 °C. Mineralization of SOC and clover leaves was observed also at 0° C. In the absence of added plant material, SOC decomposition followed a first order reaction which was twice as fast in the sandy soil as in the clay soil. The decomposition rate of clover leaves was also higher in the sandy soil than in the clay soil. However, the influence of temperature on SOC and on clover decomposition was the same in both soils. In presence of plant material, there was a positive priming effect on SOC, which initially correlated with decomposition of plant litter. There was a progressively lower priming effect at higher temperatures, particularly in the sandy soil, that could be understood as substrates exhaustion in a restricted volume of influence around the added clover leaves. We provide parameterised Arrhenius and alternative modifying linear temperature functions together with decay rates at reference temperature, which can be used for predicting decay rates of SOC per se and of the labile pool of clover leaves. We also show the superiority of these functions compared to the use of Q10 as temperature factor. Further, we suggest approaches for modelling

Correlation between landscape fragmentation and sandy desertification: a case study in Horqin Sandy Land, China.

PubMed

Ge, Xiaodong; Dong, Kaikai; Luloff, A E; Wang, Luyao; Xiao, Jun; Wang, Shiying; Wang, Qian

2016-01-01

The exact roles of landscape fragmentation on sandy desertification are still not fully understood, especially with the impact of different land use types in spatial dimension. Taking patch size and shape into consideration, this paper selected the Ratio of Patch Size and the Fractal Dimension Index to establish a model that reveals the association between the area of bare sand land and the fragmentation of different land use types adjacent to bare sand land. Results indicated that (1) grass land and arable land contributed the most to landscape fragmentation processes in the regions adjacent to bare sand land during the period 1980 to 2010. Grass land occupied 54 % of the region adjacent to bare sand land in 1980. The Ratio of Patch Size of grass land decreased from 1980 to 2000 and increased after 2000. The Fractal Dimension Index of grass increased during the period 1980 to 1990 and decreased after 1990. Arable land expanded significantly during this period. The Ratio of Patch Size of arable land increased from 1980 to 1990 and decreased since 1990. The Fractal Dimension Index of arable land increased from 1990 to 2000 and decreased after 2000. (2) The Ratio of Patch Size and the Fractal Dimension Index were significantly related to the area of bare sand land. The role of landscape fragmentation was not linear to sandy desertification. There were both positive and negative effects of landscape fragmentation on sandy desertification. In 1980, the Ratio of Patch Size and the Fractal Dimension Index were negatively related to the area of bare sand land, showing that the landscape fragmentation and regularity of patches contributed to the expansion of sandy desertification. In 1990, 2000, and 2010, the Ratio of Patch Size and the Fractal Dimension Index were mostly positively related to the area of bare sand land, showing the landscape fragmentation and regularity of patches contributed to the reversion of sandy desertification in this phase. The absolute values of

Critical soil bulk density for soybean growth in Oxisols

NASA Astrophysics Data System (ADS)

Keisuke Sato, Michel; Veras de Lima, Herdjania; Oliveira, Pedro Daniel de; Rodrigues, Sueli

2015-10-01

The aim of this study was to evaluate the critical soil bulk density from the soil penetration resistance measurements for soybean root growth in Brazilian Amazon Oxisols. The experiment was carried out in a greenhouse using disturbed soil samples collected from the northwest of Para characterized by different texture. The treatments consisted of a range of soil bulk densities for each soil textural class. Three pots were used for soybean growth of and two for the soil penetration resistance curve. From the fitted model, the critical soil bulk density was determined considering the penetration resistance values of 2 and 3 MPa. After sixty days, plants were cut and root length, dry mass of root, and dry mass of shoots were determined. At higher bulk densities, the increase in soil water content decreased the penetration resistance, allowing unrestricted growth of soybean roots. Regardless of soil texture, the penetration resistance of 2 and 3 MPa had a slight effect on root growth in soil moisture at field capacity and a reduction of 50% in the soybean root growth was achieved at critical soil bulk density of 1.82, 1.75, 1.51, and 1.45 Mg m-3 for the sandy loam, sandy clay loam, clayey, and very clayey soil.

Effect of peat on the accumulation and translocation of heavy metals by maize grown in contaminated soils.

PubMed

Stanislawska-Glubiak, Ewa; Korzeniowska, Jolanta; Kocon, Anna

2015-03-01

Incorporation of organic materials into soil improves the soil sorption capacity, while limiting the mobility of metals in soil and their availability to plants. These effects can be taken advantage for remediation of soils polluted with heavy metals. The objective of this study is to assess the remediatory potential of peat applied to soils with concomitant pollution with Cd, Pb, and Zn. Two 1-year experiments were run in microplots in which maize was grown as the test plant. The following treatments were compared on two soils (sandy soil and loess): (1) control, (2) heavy metals (HM), (3) HM + peat in a single dose, and (4) HM + peat in a double dose. Maize was harvested in the maturity stage; the biomass of roots and aerial parts, including grain and cobs, was measured. Besides, concentration of metals in all those plant parts and the net photosynthetic rate and transpiration rate were determined. The approach of using peat in soil remediation led to satisfactory results on sandy soil only. The application of peat to sandy soil caused significant changes in the accumulation of the metals and their translocation from roots to other parts of plants, which resulted in a higher intensity of photosynthesis and an increase in the maize biomass compared to the HM treatment.

Variation in Microbial Activity in Histosols and Its Relationship to Soil Moisture †

PubMed Central

Tate, Robert L.; Terry, Richard E.

1980-01-01

Microbial biomass, dehydrogenase activity, carbon metabolism, and aerobic bacterial populations were examined in cropped and fallow Pahokee muck (a lithic medisaprist) of the Florida Everglades. Dehydrogenase activity was two- to sevenfold greater in soil cropped to St. Augustinegrass (Stenotaphrum secundatum (Walt) Kuntz) compared with uncropped soil, whereas biomass ranged from equivalence in the two soils to a threefold stimulation in the cropped soil. Biomass in soil cropped to sugarcane (Saccharum spp. L) approximated that from the grass field, whereas dehydrogenase activities of the cane soil were nearly equivalent to those of the fallow soil. Microbial biomass, dehydrogenase activity, aerobic bacterial populations, and salicylate oxidation rates all correlated with soil moisture levels. These data indicate that within the moisture ranges detected in the surface soils, increased moisture stimulated microbial activity, whereas within the soil profile where moisture ranges reached saturation, increased moisture inhibited aerobic activities and stimulated anaerobic processes. PMID:16345610

Study on the water retention effect of compound soil of arsenic sandstone and sand under the condition of typical crop planting

NASA Astrophysics Data System (ADS)

Liu, S. Y.; Wang, N.; Xie, J. C.; Jiang, R. G.; Zhao, M. L.

2017-08-01

Arsenic sandstone is the main reason of soil erosion in the Mu Us Sandy Land, simultaneously was proved to be a kind of good water retaining agent. In order to provide references for the utilization of water and soil resources and the prevention and control of desertification and soil erosion of the southern margin of Mu Us Sandy Land, on the basis of earlier studies the farmland experiments of compound soil with three ratios of 1:1, 1:2 and 1:5 between arsenic sandstone and sand under maize planting patterns were designed, whose experimental process was divided into six stages according to the crop growth status. The results showed that the soil moisture content was highest in the layer of 0˜40cm where the compound soil mainly concentrated in, which was related to the potent water retention of arsenic sandstone and strong water permeability of undisturbed sandy soil. The variation coefficients in the soil of 1:1 and 1:2 were more stable and evenly distributed. The compound soil can effectively improve the soil water retention capacity, and prolong the storage time of soil water. Among them, water loss rate in soil of 1:1 and 1:2 were lower. The coefficient of variation also confirms that the water distributions of the two types of soil were more uniform and stable. Besides illustrating the effects of the soil amelioration measures on spatial and temporal variation of soil moisture content and the improvement of soil water regime, the study provides some references for the development and utilization of agriculture in Mu Us Sandy Land.

Influence of soil texture, moisture, and surface cracks on the performance of a root-feeding flea beetle, Longitarsus bethae (Coleoptera: Chrysomelidae), a biological control agent for Lantana camara (Verbenaceae).

PubMed

Simelane, David O

2007-06-01

Laboratory studies were conducted to determine the influence of soil texture, moisture and surface cracks on adult preference and survival of the root-feeding flea beetle, Longitarsus bethae Savini and Escalona (Coleoptera: Chrysomelidae), a natural enemy of the weed, Lantana camara L. (Verbenaceae). Adult feeding, oviposition preference, and survival of the immature stages of L. bethae were examined at four soil textures (clayey, silty loam, sandy loam, and sandy soil), three soil moisture levels (low, moderate, and high), and two soil surface conditions (with or without surface cracks). Both soil texture and moisture had no influence on leaf feeding and colonization by adult L. bethae. Soil texture had a significant influence on oviposition, with adults preferring to lay on clayey and sandy soils to silty or sandy loam soils. However, survival to adulthood was significantly higher in clayey soils than in other soil textures. There was a tendency for females to deposit more eggs at greater depth in both clayey and sandy soils than in other soil textures. Although oviposition preference and depth of oviposition were not influenced by soil moisture, survival in moderately moist soils was significantly higher than in other moisture levels. Development of immature stages in high soil moisture levels was significantly slower than in other soil moisture levels. There were no variations in the body size of beetles that emerged from different soil textures and moisture levels. Females laid almost three times more eggs on cracked than on noncracked soils. It is predicted that clayey and moderately moist soils will favor the survival of L. bethae, and under these conditions, damage to the roots is likely to be high. This information will aid in the selection of suitable release sites where L. bethae would be most likely to become established.

Treatability of volatile chlorinated hydrocarbon-contaminated soils of different textures along a vertical profile by mechanical soil aeration: A laboratory test.

PubMed

Ma, Yan; Shi, Yi; Hou, Deyi; Zhang, Xi; Chen, Jiaqi; Wang, Zhifen; Xu, Zhu; Li, Fasheng; Du, Xiaoming

2017-04-01

Mechanical soil aeration is a simple, effective, and low-cost soil remediation technology that is suitable for sites contaminated with volatile chlorinated hydrocarbons (VCHs). Conventionally, this technique is used to treat the mixed soil of a site without considering the diversity and treatability of different soils within the site. A laboratory test was conducted to evaluate the effectiveness of mechanical soil aeration for remediating soils of different textures (silty, clayey, and sandy soils) along a vertical profile at an abandoned chloro-alkali chemical site in China. The collected soils were artificially contaminated with chloroform (TCM) and trichloroethylene (TCE). Mechanical soil aeration was effective for remediating VCHs (removal efficiency >98%). The volatilization process was described by an exponential kinetic function. In the early stage of treatment (0-7hr), rapid contaminant volatilization followed a pseudo-first order kinetic model. VCH concentrations decreased to low levels and showed a tailing phenomenon with very slow contaminant release after 8hr. Compared with silty and sandy soils, clayey soil has high organic-matter content, a large specific surface area, a high clay fraction, and a complex pore structure. These characteristics substantially influenced the removal process, making it less efficient, more time consuming, and consequently more expensive. Our findings provide a potential basis for optimizing soil remediation strategy in a cost-effective manner. Copyright © 2016. Published by Elsevier B.V.

Amending soils with sediment material from constructed wetlands increases phosphorus sorption

NASA Astrophysics Data System (ADS)

Laakso, Johanna; Uusitalo, Risto; Leppänen, Janette; Yli-Halla, Markku

2017-04-01

Sediment of agricultural constructed wetlands (CWs) is comprised of matter eroded from surrounding fields. This material is rich in aluminium (Al) and iron (Fe) (hydr)oxides that have a high affinity for phosphorus (P). Sediment material returned to fields could therefore affect soil P retention characteristics. We incubated a clay soil with a high soil test P (STP, 24 mg PAc l-1; extracted with pH 4.65 ammonium acetate buffer) and a sandy loam with excessive STP (210 mg PAc l-1) for three weeks with increasing amounts of CW sediment: 0, 2, 5, 10 and 50% of the sample volume. After incubation, the soil-sediment mixtures were studied with the quantity/intensity (Q/I) technique, using chemical extractions and by exposing the mixtures to simulated rainfall. Sorption affinity for P regularly increased with increasing the sediment share of the mixtures, the 0% sediment content having the lowest and 50% sediment content the highest P sorption. With 0% sediment application, the value of equilibrium P concentration (EPC0) determined by Q/I technique, was 0.69 and 44.3 mg l-1 for clay soil and sandy loam, respectively. With 2-5% sediment amendment, the EPC0 decreased 13-36% for clay soil and 13-54% for sandy loam. The 50% sediment mixtures had EPC0 of 0.05 mg l-1 for both soils. At a practically feasible sediment addition rate of 5%, dissolved reactive P (DRP) in percolating water from simulated rainfall decreased by 55% in the clay soil and 54% in sandy loam (p<0.001 in both cases). Particulate-P (PP) also showed a decreasing trend with increasing sediment addition rate. Upon prolonged simulated rainfall, the decreasing effect of sediment on DRP and PP declined somewhat. The effects of sediment addition can be attributed partly to increased salt concentrations in the sediment, which have a short-term effect on P mobilisation, but mostly to increased concentrations of Al and Fe (hydr)oxides, increasing long-term P sorption capacity. Amending the soils with sediment material

Features of abandoned cemetery soils on sandy substrates in Northern Poland

NASA Astrophysics Data System (ADS)

Majgier, L.; Rahmonov, O.; Bednarek, R.

2014-06-01

Morphological and chemical features of cemetery soils (Necrosols and undisturbed cemetery soils) have been studied with Northern Poland as an example. Special attention has been given to the contents of the total phosphorus (as an indicator of the anthropogenic impact); the organic carbon; the total nitrogen; the calcium carbonate; and the changes in the acidity and total Ca, Na, K, Al, Fe, Mg, Zn, Cd, and Pb. The soil profiles have been compared to the control soil (a Brunic Arenosol according to the WRB classification) occurring beyond the cemetery area. The changes in the studied burial soils are mainly manifested in their morphology: the disturbance of the primary genetic horizons and the presence of mixed soil horizons and artifacts (bones, coffin remains, limestone-concrete debris of the cemetery infrastructure). Such changes in the chemical properties as an increase in the contents of the organic carbon and total nitrogen and the soil reaction were observed. Our studies have shown that the highest Ptotal concentration is observed in the A horizons of the anthropogenic burial horizons and undisturbed cemetery soils. The content of phosphorus in the Necrosols is significantly higher than that in the control soil profile, as is observed for the Cgrb layers of burial Necrosols. The morphology and chemistry of the undisturbed cemetery soils are very similar to those of the control profile.

Hydrodispersive characterization of a sandy porous medium by tracer tests carried out in laboratory on undisturbed soil samples

NASA Astrophysics Data System (ADS)

Ferrante, Aldo Pedro; Fallico, Carmine; Rios, Ana C.; Fernanda Rivera, Maria; Santillan, Patricio; Salazar, Mario

2013-04-01

The contamination of large areas and correspondent aquifers often imposes to implement some recovery operations which are generally complex and very expensive. Anyway, these interventions necessarily require the preventive characterization of the aquifers to be reclaimed and in particular the knowledge of the relevant hydrodispersive parameters. The determination of these parameters requires the implementation tracer tests for the specific site (Sauty JP, 1978). To reduce cost and time that such test requires tracer tests on undisturbed soil samples, representative of the whole aquifer, can be performed. These laboratory tests are much less expensive and require less time, but the results are certainly less reliable than those obtained by field tests for several reasons, including the particular scale of investigation. In any case the hydrodispersive parameters values, obtained by tests carried out in laboratory, can provide useful information on the considered aquifer, allowing to carry out initial verifications on the transmission and propagation of the pollutants in the aquifer considered. For this purpose, tracer tests with inlet of short time were carried out in the Soil Physics Laboratory of the Department of Soil Protection (University of Calabria), on a series of sandy soil samples with six different lengths, repeating each test with three different water flow velocities (5 m/d; 10 m/s and 15 m/d) (J. Feyen et al., 1998). The lengths of the samples taken into account are respectively 15 cm, 24 cm, 30 cm, 45 cm, 60 cm and 75 cm, while the solution used for each test was made of 100 ml of water and NaCl with a concentration of this substance corresponding to 10 g/L. For the porous medium taken into consideration a particle size analysis was carried out, resulting primarily made of sand, with total porosity equal to 0.33. Each soil sample was placed in a flow cell in which was inlet the tracer from the bottom upwards, measuring by a conductivimeter the

Fungal Community Responses to Past and Future Atmospheric CO2 Differ by Soil Type

PubMed Central

Ellis, J. Christopher; Fay, Philip A.; Polley, H. Wayne; Jackson, Robert B.

2014-01-01

Soils sequester and release substantial atmospheric carbon, but the contribution of fungal communities to soil carbon balance under rising CO2 is not well understood. Soil properties likely mediate these fungal responses but are rarely explored in CO2 experiments. We studied soil fungal communities in a grassland ecosystem exposed to a preindustrial-to-future CO2 gradient (250 to 500 ppm) in a black clay soil and a sandy loam soil. Sanger sequencing and pyrosequencing of the rRNA gene cluster revealed that fungal community composition and its response to CO2 differed significantly between soils. Fungal species richness and relative abundance of Chytridiomycota (chytrids) increased linearly with CO2 in the black clay (P < 0.04, R2 > 0.7), whereas the relative abundance of Glomeromycota (arbuscular mycorrhizal fungi) increased linearly with elevated CO2 in the sandy loam (P = 0.02, R2 = 0.63). Across both soils, decomposition rate was positively correlated with chytrid relative abundance (r = 0.57) and, in the black clay soil, fungal species richness. Decomposition rate was more strongly correlated with microbial biomass (r = 0.88) than with fungal variables. Increased labile carbon availability with elevated CO2 may explain the greater fungal species richness and Chytridiomycota abundance in the black clay soil, whereas increased phosphorus limitation may explain the increase in Glomeromycota at elevated CO2 in the sandy loam. Our results demonstrate that soil type plays a key role in soil fungal responses to rising atmospheric CO2. PMID:25239904

The medically important aerobic actinomycetes: epidemiology and microbiology.

PubMed Central

McNeil, M M; Brown, J M

1994-01-01

The aerobic actinomycetes are soil-inhabiting microorganisms that occur worldwide. In 1888, Nocard first recognized the pathogenic potential of this group of microorganisms. Since then, several aerobic actinomycetes have been a major source of interest for the commercial drug industry and have proved to be extremely useful microorganisms for producing novel antimicrobial agents. They have also been well known as potential veterinary pathogens affecting many different animal species. The medically important aerobic actinomycetes may cause significant morbidity and mortality, in particular in highly susceptible severely immunocompromised patients, including transplant recipients and patients infected with human immunodeficiency virus. However, the diagnosis of these infections may be difficult, and effective antimicrobial therapy may be complicated by antimicrobial resistance. The taxonomy of these microorganisms has been problematic. In recent revisions of their classification, new pathogenic species have been recognized. The development of additional and more reliable diagnostic tests and of a standardized method for antimicrobial susceptibility testing and the application of molecular techniques for the diagnosis and subtyping of these microorganisms are needed to better diagnose and treat infected patients and to identify effective control measures for these unusual pathogens. We review the epidemiology and microbiology of the major medically important aerobic actinomycetes. Images PMID:7923055

Critical evaluation of the use of the hydroxyapatite as a stabilizing agent to reduce the mobility of Zn and Ni in sewage sludge amended soils.

PubMed

Zupancic, Marija; Bukovec, Peter; Milacic, Radmila; Scancar, Janez

2006-01-01

The leachability of zinc (Zn) and nickel (Ni) was investigated in various soil types amended with sewage sludge and sewage sludge treated with hydroxyapatite. Sandy, clay and peat soils were investigated. For leachability tests, plastic columns (diameter 9 cm, height 50 cm) were filled with moist samples up to a height of 25 cm. Sewage sludge (1 kg) was mixed with 4.6 kg of clay and sandy soils and with 6.7 kg of peat soil. For sewage sludge mixtures treated with hydroxyapatite, 0.5 kg of the hydroxyapatite was added to 1 kg of the sewage sludge. Neutral (pH 7) and acid precipitation (pH 3.5) were applied. Acid precipitation was prepared from concentrated HNO(3), H(2)SO(4) and fresh doubly distilled water. The amount of precipitation corresponded to the average annual precipitation for the city of Ljubljana, Slovenia. It was divided into eight equal portions and applied sequentially on the top of the columns. The results indicated that the leachabilities of Zn in sewage sludge amended peat and clay soils were low (below 0.3% of total Zn content) and of Ni in sewage sludge amended sandy, clay and peat soil below 1.9% of total Ni content. In sewage sludge amended sandy soil, the leachability of Zn was higher (11% of Zn content). The pH of precipitation had no influence on the leachability of either metal. Treatment of sewage sludge with hydroxyapatite efficiently reduced the leachability of Zn in sewage sludge amended sandy soil (from 11% to 0.2% of total Zn content). In clay and peat sewage sludge amended soils, soil characteristics rather than hydroxyapatite treatment dominate Zn mobility.

Termite infestation associated with type of soil in pulau pinang, malaysia (isoptera: rhinotermitidae).

PubMed

Majid, Abdul Hafiz Ab; Ahmad, Abu Hassan

2013-12-01

Nine soil samples from nine buildings infested with Coptotermes gestroi in Pulau Pinang, Malaysia, were tested for the type of soil texture. The soil texture analysis procedures used the hydrometer method. Four of nine buildings (44%) yielded loamy sand-type soil, whereas five of nine buildings (56%) contained sandy loam-type soil.

Statistical process control applied to mechanized peanut sowing as a function of soil texture.

PubMed

Zerbato, Cristiano; Furlani, Carlos Eduardo Angeli; Ormond, Antonio Tassio Santana; Gírio, Lucas Augusto da Silva; Carneiro, Franciele Morlin; da Silva, Rouverson Pereira

2017-01-01

The successful establishment of agricultural crops depends on sowing quality, machinery performance, soil type and conditions, among other factors. This study evaluates the operational quality of mechanized peanut sowing in three soil types (sand, silt, and clay) with variable moisture contents. The experiment was conducted in three locations in the state of São Paulo, Brazil. The track-sampling scheme was used for 80 sampling locations of each soil type. Descriptive statistics and statistical process control (SPC) were used to evaluate the quality indicators of mechanized peanut sowing. The variables had normal distributions and were stable from the viewpoint of SPC. The best performance for peanut sowing density, normal spacing, and the initial seedling growing stand was found for clayey soil followed by sandy soil and then silty soil. Sandy or clayey soils displayed similar results regarding sowing depth, which was deeper than in the silty soil. Overall, the texture and the moisture of clayey soil provided the best operational performance for mechanized peanut sowing.

Statistical process control applied to mechanized peanut sowing as a function of soil texture

PubMed Central

Furlani, Carlos Eduardo Angeli; da Silva, Rouverson Pereira

2017-01-01

The successful establishment of agricultural crops depends on sowing quality, machinery performance, soil type and conditions, among other factors. This study evaluates the operational quality of mechanized peanut sowing in three soil types (sand, silt, and clay) with variable moisture contents. The experiment was conducted in three locations in the state of São Paulo, Brazil. The track-sampling scheme was used for 80 sampling locations of each soil type. Descriptive statistics and statistical process control (SPC) were used to evaluate the quality indicators of mechanized peanut sowing. The variables had normal distributions and were stable from the viewpoint of SPC. The best performance for peanut sowing density, normal spacing, and the initial seedling growing stand was found for clayey soil followed by sandy soil and then silty soil. Sandy or clayey soils displayed similar results regarding sowing depth, which was deeper than in the silty soil. Overall, the texture and the moisture of clayey soil provided the best operational performance for mechanized peanut sowing. PMID:28742095

Solubility of lead and copper in biochar-amended small arms range soils: influence of soil organic carbon and pH.

PubMed

Uchimiya, Minori; Bannon, Desmond I

2013-08-14

Biochar is often considered a strong heavy metal stabilizing agent. However, biochar in some cases had no effects on, or increased the soluble concentrations of, heavy metals in soil. The objective of this study was to determine the factors causing some biochars to stabilize and others to dissolve heavy metals in soil. Seven small arms range soils with known total organic carbon (TOC), cation exchange capacity, pH, and total Pb and Cu contents were first screened for soluble Pb and Cu concentrations. Over 2 weeks successive equilibrations using weak acid (pH 4.5 sulfuric acid) and acetate buffer (0.1 M at pH 4.9), Alaska soil containing disproportionately high (31.6%) TOC had nearly 100% residual (insoluble) Pb and Cu. This soil was then compared with sandy soils from Maryland containing significantly lower (0.5-2.0%) TOC in the presence of 10 wt % (i) plant biochar activated to increase the surface-bound carboxyl and phosphate ligands (PS450A), (ii) manure biochar enriched with soluble P (BL700), and (iii) unactivated plant biochars produced at 350 °C (CH350) and 700 °C (CH500) and by flash carbonization (corn). In weak acid, the pH was set by soil and biochar, and the biochars increasingly stabilized Pb with repeated extractions. In pH 4.9 acetate buffer, PS450A and BL700 stabilized Pb, and only PS450A stabilized Cu. Surface ligands of PS450A likely complexed and stabilized Pb and Cu even under acidic pH in the presence of competing acetate ligand. Oppositely, unactivated plant biochars (CH350, CH500, and corn) mobilized Pb and Cu in sandy soils; the putative mechanism is the formation of soluble complexes with biochar-borne dissolved organic carbon. In summary, unactivated plant biochars can inadvertently increase dissolved Pb and Cu concentrations of sandy, low TOC soils when used to stabilize other contaminants.

Predicting Impact of Biochar Addition on Soil Hydraulic Properties

NASA Astrophysics Data System (ADS)

Nakhli, S. A. A.; Yudi, Y.; Imhoff, P. T.

2017-12-01

Biochar has been proposed as a soil amendment to improve soil hydraulic properties, including water retention and saturated and unsaturated hydraulic conductivity, for agricultural and environmental applications. However, its effect on hydraulic properties is difficult to predict and often with mixed results: in some cases biochar enhances soil hydraulic properties, while in other cases it degrades them. Despite several published observational studies, there are no models that can reliably predict biochar's impact on soil hydraulic properties. In this project we developed models to describe the effect of addition of a commercial wood biochar pyrolyzed at 550° on soil hydraulic properties in laboratory-scale experiments. The effects of biochar addition at 2% and 6% (w/w) on water retention and saturated and unsaturated hydraulic conductivity were evaluated for silt loam, sandy loam, and loamy sand. The addition of 6% (w/w) biochar increased the available water content of silt loam, sandy loam and loamy sand by 25, 20 and 70%, respectively. The impact of biochar addition on water retention was predicted reasonably well using information on the intra particle pore volume of biochar (mercury porosimetry, N2 and CO2 sorption) and the particle size distribution of the soil/biochar mixture. When amended with 6% biochar, saturated hydraulic conductivity increased 17% for loamy sand, but decreased 30% and 54% for silt loam and sandy loam, respectively. The Kozeny-Carman equation modified to account for changes in inter pore volume predicted saturated hydraulic conductivities of the biochar-amended soils reasonably well, with RMSE ranging from 0.06 to 5.06 cm h-1 for silt loam and loamy sand, respectively. While intra particle pore volume of biochar contributed significantly to higher water retention, changes in hydraulic conductivity were correlated instead with changes in inter pore volume - the large pores between biochar and soil particles.

Determining photon energy absorption parameters for different soil samples

PubMed Central

Kucuk, Nil; Tumsavas, Zeynal; Cakir, Merve

2013-01-01

The mass attenuation coefficients (μs) for five different soil samples were measured at 661.6, 1173.2 and 1332.5 keV photon energies. The soil samples were separately irradiated with 137Cs and 60Co (370 kBq) radioactive point gamma sources. The measurements were made by performing transmission experiments with a 2″ × 2″ NaI(Tl) scintillation detector, which had an energy resolution of 7% at 0.662 MeV for the gamma-rays from the decay of 137Cs. The effective atomic numbers (Zeff) and the effective electron densities (Neff) were determined experimentally and theoretically using the obtained μs values for the soil samples. Furthermore, the Zeff and Neff values of the soil samples were computed for the total photon interaction cross-sections using theoretical data over a wide energy region ranging from 1 keV to 15 MeV. The experimental values of the soils were found to be in good agreement with the theoretical values. Sandy loam and sandy clay loam soils demonstrated poor photon energy absorption characteristics. However, clay loam and clay soils had good photon energy absorption characteristics. PMID:23179375

Spectral induced polarization (SIP) measurement of NAPL contaminated soils

NASA Astrophysics Data System (ADS)

Schwartz, N.; Huisman, J. A.; Furman, A.

2010-12-01

The potential applicability of spectral induce polarization (SIP) as a tool to map NAPLs (non aqueous phase liquids) contaminants at the subsurface lead researchers to investigate the electric signature of those contaminant on the spectral response. However, and despite the cumulative efforts, the effect of NAPL on the electrical properties of soil, and the mechanisms that control this effect are largely unknown. In this work a novel experiment is designed to further examine the effect of NAPL on the electrical properties of partially saturated soil. The measurement system that used is the ZEL-SIP04 impedance meter developed at the Forschungszentrum Julich, Germany. The system accurately (nominal phase precision of 0.1 mrad below 1 kHz) measures the phase and the amplitude of a material possessing a very low polarization (such as soil). The sample holder has a dimension of 60 cm long and 4.6 cm in diameter. Current and potential electrodes were made of brass, and while the current electrodes were inserted in full into the soil, the contact between the potential electrode and the soil was made through an Agarose bridge. Two types of soils were used: clean quartz sand, and a mixture of sand with clean Bentonite. Each soil (sandy or clayey) was mixed with water to get saturation degree of 30%. Following the mixture with water, NAPL was added and the composite were mixed again. Packing was done by adding and compressing small portions of the soil to the column. A triplicate of each mixture was made with a good reproducible bulk density. Both for the sandy and clayey soils, the results indicate that additions of NAPL decrease the real part of the complex resistivity. Additionally, for the sandy soil this process is time depended, and that a further decrease in resistivity develops over time. The results are analyzed considering geometrical factors: while the NAPL is electrically insulator, addition of NAPL to the soil is expected to increase the connectivity of the

The Role of Teak Leaves (Tectona grandis), Rhizobium, and Vesicular-Arbuscular Mycorrhizae on Improving Soil Structure and Soil Nutrition

NASA Astrophysics Data System (ADS)

Yuliani; Rahayu, Y. S.

2018-01-01

Calcium is the largest mineral in calcareous soils. High levels of calcium carbonate lead to phosphate deposition. Nutrient deficiencies in calcareous soil (mainly Phosphate and Nitrogen) resulted only certain crops with a wide range of tolerances that can grow. Meanwhile, dynamics nutrient in calcareous soils also depend on the topography and decomposition of the litter in the growing vegetation. The purpose of this study was to describe the pattern of nutrient enhancement and soil-texture structures on calcareous soils after littering the teak leaves, Rhizobium and Vesicular Arbuscular Mycorrhiza. The research parameters were the concentration of N, P, K; C/N ratio, humid acid content, and soil structure, which measured at days 30, 60, and 85 of soil decomposition process. The results showed that at days 30, the texture and structure of the soil tend to be stable (porosity 31.2, DMR 1.93, moisture content 0.36, sandy clay) while at days 85 has been very stable (porosity 49.8; Water content 0.28, sandy clay). While C and N organic, N and K concentration at days 30 showed low value (C organic 1.03, N 0.12, K 0.49, C / N ratio 9). This condition is almost unchanged at days 85. While the P value shows very high value (60.53) at days 30 although after 60 days the P content showed a decrease.

Termite Infestation Associated with Type of Soil in Pulau Pinang, Malaysia (Isoptera: Rhinotermitidae)

PubMed Central

Majid, Abdul Hafiz Ab; Ahmad, Abu Hassan

2013-01-01

Nine soil samples from nine buildings infested with Coptotermes gestroi in Pulau Pinang, Malaysia, were tested for the type of soil texture. The soil texture analysis procedures used the hydrometer method. Four of nine buildings (44%) yielded loamy sand-type soil, whereas five of nine buildings (56%) contained sandy loam-type soil. PMID:24575252

Processing protocol for soil samples potentially contaminated with Bacillus anthracis spores [HS7.52.02 - 514

USGS Publications Warehouse

Silvestri, Erin E.; Griffin, Dale W.

2017-01-01

This protocol describes the processing steps for 45 g and 9 g soil samples potentially contaminated with Bacillus anthracis spores. The protocol is designed to separate and concentrate the spores from bulk soil down to a pellet that can be used for further analysis. Soil extraction solution and mechanical shaking are used to disrupt soil particle aggregates and to aid in the separation of spores from soil particles. Soil samples are washed twice with soil extraction solution to maximize recovery. Differential centrifugation is used to separate spores from the majority of the soil material. The 45 g protocol has been demonstrated by two laboratories using both loamy and sandy soil types. There were no significant differences overall between the two laboratories for either soil type, suggesting that the processing protocol would be robust enough to use at multiple laboratories while achieving comparable recoveries. The 45 g protocol has demonstrated a matrix limit of detection at 14 spores/gram of soil for loamy and sandy soils.

Soil catenas on denudation plains in the forest-tundra and northern taiga zones of the Kola Peninsula

NASA Astrophysics Data System (ADS)

Urusevskaya, I. S.

2017-07-01

Morphogenetic features of soils of two catenas developed on sandy to loamy sandy moraine deposits in the forest-tundra and northern taiga zones on denudation plains of the Kola Peninsula are discussed. It is shown that these catenas are similar with respect to the major directions of soil formation, regularities of soil distribution by the elements of mesotopography, and the factors of the soil cover differentiation. The differences between the catenas are of quantitative character and are related to the intensities of manifestation of the particular processes and features. Both catenas are characterized by the pronounced differentiation of soils with respect to their moistening with hydromorphic peat bog soils in the subordinate positions and Al-Fe-humus podzols in the automorphic positions.

Metals in European roadside soils and soil solution--a review.

PubMed

Werkenthin, Moritz; Kluge, Björn; Wessolek, Gerd

2014-06-01

This review provides a summary of studies analysing metal concentrations in soils and soil solution at European roadsides. The data collected during 27 studies covering a total of 64 sites across a number of European countries were summarised. Highest median values of Cr, Cu, Ni, Pb, and Zn were determined in the top soil layer at the first 5 m beside the road. Generally, the influence of traffic on soil contamination decreased with increasing soil depth and distance to the road. The concentration patterns of metals in soil solution were independent from concentrations in the soil matrix. At 10-m distance, elevated soil metal concentrations, low pH, and low percolation rates led to high solute concentrations. Directly beside the road, high percolation rates lead to high annual loadings although solute concentrations are comparatively low. These loadings might be problematic, especially in regions with acidic sandy soils and a high groundwater table. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fate of trace organic compounds during vadose zone soil treatment in an onsite wastewater system

USGS Publications Warehouse

Conn, K.E.; Siegrist, R.L.; Barber, L.B.; Meyer, M.T.

2010-01-01

During onsite wastewater treatment, trace organic compounds are often present in the effluents applied to subsurface soils for advanced treatment during vadose zone percolation and groundwater recharge. The fate of the endocrine-disrupting surfactant metabolites 4-nonylphenol (NP), 4-nonylphenolmonoethoxylate (NP1EO), and 4-nonylphenolmonoethoxycarboxylate (NP1EC), metal-chelating agents ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA), antimicrobial agent triclosan, stimulant caffeine, and antibiotic sulfamethoxazole during transport through an unsaturated sandy loam soil was studied at a field-scale test site. To assess the effects of effluent quality and hydraulic loading rate (HLR) on compound fate in the soil profile, two effluents (septic tank or textile biofilter) were applied at two design HLRs (2 or 8 cm/d). Chemical concentrations were determined in the two effluents and soil pore water at 60, 120, and 240 cm below the soil infiltrative surface. Concentrations of trace organic compounds in septic tank effluent were reduced by more than 90% during transport through 240 cm (often within 60 cm) of soil, likely due to sorption and biotransformation. However, the concentration of NP increased with depth in the shallow soil profile. Additional treatment of anaerobic septic tank effluent with an aerobic textile biofilter reduced effluent concentrations of many compounds, but generally did not affect any changes in pore water concentrations. The soil profile receiving septic tank effluent (vs. textile biofilter effluent) generally had greater percent removal efficiencies. EDTA, NP, NP1EC, and sulfamethoxazole were measured in soil pore water, indicating the ability of some trace organic compounds to reach shallow groundwater. Risk is highly dependent on the degree of further treatment in the saturated zone and the types and proximity of uses for the receiving groundwater environment. ?? 2009 SETAC.

Fate of trace organic compounds during vadose zone soil treatment in an onsite wastewater system.

PubMed

Conn, Kathleen E; Siegrist, Robert L; Barber, Larry B; Meyer, Michael T

2010-02-01

During onsite wastewater treatment, trace organic compounds are often present in the effluents applied to subsurface soils for advanced treatment during vadose zone percolation and groundwater recharge. The fate of the endocrine-disrupting surfactant metabolites 4-nonylphenol (NP), 4-nonylphenolmonoethoxylate (NP1EO), and 4-nonylphenolmonoethoxycarboxylate (NP1EC), metal-chelating agents ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA), antimicrobial agent triclosan, stimulant caffeine, and antibiotic sulfamethoxazole during transport through an unsaturated sandy loam soil was studied at a field-scale test site. To assess the effects of effluent quality and hydraulic loading rate (HLR) on compound fate in the soil profile, two effluents (septic tank or textile biofilter) were applied at two design HLRs (2 or 8 cm/d). Chemical concentrations were determined in the two effluents and soil pore water at 60, 120, and 240 cm below the soil infiltrative surface. Concentrations of trace organic compounds in septic tank effluent were reduced by more than 90% during transport through 240 cm (often within 60 cm) of soil, likely due to sorption and biotransformation. However, the concentration of NP increased with depth in the shallow soil profile. Additional treatment of anaerobic septic tank effluent with an aerobic textile biofilter reduced effluent concentrations of many compounds, but generally did not affect any changes in pore water concentrations. The soil profile receiving septic tank effluent (vs. textile biofilter effluent) generally had greater percent removal efficiencies. EDTA, NP, NP1EC, and sulfamethoxazole were measured in soil pore water, indicating the ability of some trace organic compounds to reach shallow groundwater. Risk is highly dependent on the degree of further treatment in the saturated zone and the types and proximity of uses for the receiving groundwater environment. Copyright 2009 SETAC.

A Constitutive Relationship for Gravelly Soil Considering Fine Particle Suffusion

PubMed Central

Zhang, Yuning; Chen, Yulong

2017-01-01

Suffusion erosion may occur in sandy gravel dam foundations that use suspended cutoff walls. This erosion causes a loss of fine particles, degrades the soil strength and deformation moduli, and adversely impacts the cutoff walls of the dam foundation, as well as the overlying dam body. A comprehensive evaluation of these effects requires models that quantitatively describe the effects of fine particle losses on the stress-strain relationships of sandy gravels. In this work, we propose an experimental scheme for studying these types of models, and then perform triaxial and confined compression tests to determine the effects of particle losses on the stress-strain relationships. Considering the Duncan-Chang E-B model, quantitative expressions describing the relationship between the parameters of the model and the particle losses were derived. The results show that particle losses did not alter the qualitative stress-strain characteristics of the soils; however, the soil strength and deformation moduli were degraded. By establishing the relationship between the parameters of the model and the losses, the same model can then be used to describe the relationship between sandy gravels and erosion levels that vary in both time and space. PMID:29065532

Differences in impacts of Hurricane Sandy on freshwater swamps on the Delmarva Peninsula, Mid−Atlantic Coast, USA

USGS Publications Warehouse

Middleton, Beth A.

2016-01-01

Hurricane wind and surge may have different influences on the subsequent composition of forests. During Hurricane Sandy, while damaging winds were highest near landfall in New Jersey, inundation occurred along the entire eastern seaboard from Georgia to Maine. In this study, a comparison of damage from salinity intrusion vs. wind/surge was recorded in swamps of the Delmarva Peninsula along the Pocomoke (MD) and Nanticoke (DE) Rivers, south of the most intense wind damage. Hickory Point Cypress Swamp (Hickory) was closest to the Chesapeake Bay and may have been subjected to a salinity surge as evidenced by elevated salinity levels at a gage upstream of this swamp (storm salinity = 13.1 ppt at Nassawango Creek, Snow Hill, Maryland). After Hurricane Sandy, 8% of the standing trees died at Hickory including Acer rubrum, Amelanchier laevis, Ilex spp., and Taxodium distichum. In Plot 2 of Hickory, 25% of the standing trees were dead, and soil salinity levels were the highest recorded in the study. The most important variables related to structural tree damage were soil salinity and proximity to the Atlantic coast as based on Stepwise Regression and NMDS procedures. Wind damage was mostly restricted to broken branches although tipped−up trees were found at Hickory, Whiton and Porter (species: Liquidamabar styraciflua, Pinus taeda, Populus deltoides, Quercus pagoda and Ilex spp.). These trees fell mostly in an east or east−southeast direction (88o−107o) in keeping with the wind direction of Hurricane Sandy on the Delmarva Peninsula. Coastal restoration and management can be informed by the specific differences in hurricane damage to vegetation by salt versus wind.

[Effects of biochar addition into soils in semiarid land on water infiltration under the condition of the same bulk density].

PubMed

Qi, Rui-Peng; Zhang, Lei; Yan, Yong-Hao; Wen, Man; Zheng, Ji-Yong

2014-08-01

Making clear the effects of biochar addition on soil water infiltration process can provide the scientific basis for the evaluation of the influence of biochar application on soil hydrology in semi-arid region. In this paper, through the soil column simulation method in laboratory, the effects of biochar of three sizes (1-2 mm, 0.25-1 mm and ≤ 0.25 mm) at 4 doses (10, 50, 100 and 150 g x kg(-1)) on the cumulative infiltration, the permeability and the stable infiltration rate of two different soils (anthrosol and aeolian sandy soil) were studied. The results showed that the infiltration capacity of the anthrosol was obviously increased compared to the control, however, the one in the aeolian sandy soil was decreased due to the biochar addition. At 100 minutes after infiltration starting, the averaged cumulative infiltration was increased by 25.1% in the anthrosol with comparison to the control. Contrarily, the averaged cumulative infiltration was decreased by 11.1% in the aeolian sandy soil at 15 minutes after infiltration starting. When the dose was the same, biochar with different particle sizes improved the infiltration for the anthrosol, but for the different dose treatments, the particle size of biochar which showed the greatest improvement was different. As for the aeolian sandy soil, the infiltration increased at the dose of 10 g x kg(-1) after the addition of biochar with different particle sizes, while decreased at the higher dose of 50, 100 and 150 g x kg(-1). The cumulative infiltration of the aeolian sandy soil was decreased with the increase in addition amount of biochar with the same particle size, while it was not so for the anthrosol. The determination coefficient fitted by the Philip infiltration model ranged from 0.965 to 0.999, suggesting this model was suitable for the simulation of soil water infiltration process after biochar application. Statistical analysis of main effects showed that the biochar particle size, the biochar addition amount

Observed effects of soil organic matter content on the microwave emissivity of soils

NASA Technical Reports Server (NTRS)

O'Neill, P. E.; Jackson, T. J.

1990-01-01

In order to determine the significance of organic matter content on the microwave emissivity of soils when estimating soil moisture, field experiments were conducted in which 1.4 GHz microwave emissivity data were collected over test plots of sandy loam soil with different organic matter levels (1.8, 4.0, and 6.1 percent) for a range of soil moisture values. Analyses of the observed data show only minor variation in microwave emissivity due to a change in organic matter content at a given moisture level for soils with similar texture and structure. Predictions of microwave emissivity made using a dielectric model for aggregated soils exhibit the same trends and type of response as the measured data when appropriate values for the input parameters were utilized.

Observed effects of soil organic matter content on the microwave intensity of soils

NASA Technical Reports Server (NTRS)

Jackson, T. J.; Oneill, P. E.

1988-01-01

In order to determine the significance of organic matter content on the microwave emissivity of soils when estimating soil moisture, field experiments were conducted in which 1.4 GHz microwave emissivity data were collected over test plots of sandy loam soil with different organic matter levels (1.8, 4.0, and 6.1 percent) for a range of soil moisture values. Analyses of the observed data show only minor variation in microwave emissivity due to a change in organic matter content at a given moisture level for soils with similar texture and structure. Predictions of microwave emissivity made using a dielectric model for aggregated soils exhibit the same trends and type of response as the measured data when appropriate values for the input parameters were utilized.

Effect of soil texture on the microwave emission from soils

NASA Technical Reports Server (NTRS)

Schmugge, T. J.

1980-01-01

The intensity brightness temperature of the microwave emission from the soil is determined primarily by its dielectric properties. The large difference between the dielectric constant of water and that of dry soil produces a strong dependence of the soil's dielectric constant on its moisture content. This dependence is effected by the texture of the soil because the water molecules close to the particle surface are tightly bound and do not contribute significantly to the dielectric properties. Since this surface area is a function of the particle size distribution (soil texture), being larger for clay soils with small particles, and smaller for sandy soils with larger particles; the dielectric properties will depend on soil texture. Laboratory measurements of the dielectric constant for soils are summarized. The dependence of the microwave emission on texture is demonstrated by measurements of brightness temperature from an aircraft platform for a wide range of soil textures. It is concluded that the effect of soil texture differences on the observed values can be normalized by expressing the soil moisture values as a percent field capacity for the soil.

Evaporation From Soil Containers With Irregular Shapes

NASA Astrophysics Data System (ADS)

Assouline, Shmuel; Narkis, Kfir

2017-11-01

Evaporation from bare soils under laboratory conditions is generally studied using containers of regular shapes where the vertical edges are parallel to the flow lines in the drying domain. The main objective of this study was to investigate the impact of irregular container shapes, for which the flow lines either converge or diverge toward the surface. Evaporation from initially saturated sand and sandy loam soils packed in cones and inverted cones was compared to evaporation from corresponding cylindrical columns. The initial evaporation rate was higher in the cones, and close to potential evaporation. At the end of the experiment, the cumulative evaporation depth in the sand cone was equal to that in the column but higher than in the inverted cone, while in the sandy loam, the order was cone > column > inverted cone. By comparison to the column, stage 1 evaporation was longer in the cones, and practically similar in the inverted cones. Stage 2 evaporation rate decreased with the increase of the evaporating surface area. These results were more pronounced in the sandy loam. For the sand column, the transition between stage 1 and stage 2 evaporation occurred when the depth of the saturation front was approximately equal to the characteristic length of the soil. However, for the cone and the inverted cone, it occurred for a shallower depth of the saturation front. It seems therefore that the concept of the characteristic length derived from the soil hydraulic properties is related to drying systems of regular shapes.

Differential sensitivity of aerobic gram-positive and gram-negative microorganisms to 2,4,6-trinitrotoluene (TNT) leads to dissimilar growth and TNT transformation: Results of soil and pure culture studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fuller, M.E.; Manning, J.F. Jr.

1996-07-30

The effects of 2,4,6-trinitrotoluene (TNT) on indigenous soil populations and pure bacterial cultures were examined. The number of colony-forming units (CFU) appearing when TNT-contaminated soil was spread on 0.3% molasses plates decreased by 50% when the agar was amended with 67 {mu}g TNT mL{sup -1}, whereas a 99% reduction was observed when uncontaminated soil was plated. Furthermore, TNT-contaminated soil harbored a greater number of organisms able to grow on plates amended with greater than 10 {mu}g TNT mL{sup -1}. The percentage of gram-positive isolates was markedly less in TNT-contaminated soil (7%; 2 of 30) than in uncontaminated soil (61%; 20more » of 33). Pseudomonas aeruginosa, Pseudomonas corrugate, Pseudomonasfluorescens and Alcaligenes xylosoxidans made up the majority of the gram-negative isolates from TNT-contaminated soil. Gram-positive isolates from both soils demonstrated marked growth inhibition when greater than 8-16 {mu}g TNT mL{sup -1} was present in the culture media. Most pure cultures of known aerobic gram-negative organisms readily degraded TNT and evidenced net consumption of reduced metabolites. However, pure cultures of aerobic gram-positive bacteria were sensitive to relatively low concentrations of TNT as indicated by the 50% reduction in growth and TNT transformation which was observed at approximately 10 {mu}g TNT mL{sup -1}. Most non-sporeforming gram-positive organisms incubated in molasses media amended with 80 {mu}g TNT mL{sup -1} or greater became unculturable, whereas all strains tested remained culturable when incubated in mineral media amended with 98 {mu}g TNT mL{sup -1}, indicating that TNT sensitivity is likely linked to cell growth. These results indicate that gram-negative organisms are most likely responsible for any TNT transformation in contaminated soil, due to their relative insensitivity to high TNT concentrations and their ability to transform TNT.« less

Content Analysis of Select YouTube Postings: Comparisons of Reactions to the Sandy Hook and Aurora Shootings and Hurricane Sandy.

PubMed

Miller, Eric D

2015-11-01

This study details an innovative and methodical content analysis of 2,207 YouTube comments from four different YouTube videos (e.g., breaking news or memorials) related to the 2012 Sandy Hook Elementary School and Aurora theater mass shootings and the catastrophic Hurricane Sandy. As expected, YouTube comments associated with the Sandy Hook shootings (particularly those from a memorial video) were especially likely to feature compassion and grief with lessened hostility. This study highlights differing online contexts by which individuals show grief and related emotions following man-made and natural calamities and how-even in an online environment-powerful situational contexts greatly guide behavior.

OSCAT Eyes Hurricane Sandy

NASA Image and Video Library

2012-10-30

This image shows ocean surface winds for Hurricane Sandy observed by the OSCAT radar scatterometer on the Indian Space Research Organization ISRO OceanSat-2 satellite. Colors indicate wind speed and arrows indicate direction.

Identification of TCE and PCE sorption and biodegradation parameters in a sandy aquifer for fate and transport modelling: batch and column studies.

PubMed

Kret, E; Kiecak, A; Malina, G; Nijenhuis, I; Postawa, A

2015-07-01

The main aim of this study was to determine the sorption and biodegradation parameters of trichloroethene (TCE) and tetrachloroethene (PCE) as input data required for their fate and transport modelling in a Quaternary sandy aquifer. Sorption was determined based on batch and column experiments, while biodegradation was investigated using the compound-specific isotope analysis (CSIA). The aquifer materials medium (soil 1) to fine (soil 2) sands and groundwater samples came from the representative profile of the contaminated site (south-east Poland). The sorption isotherms were approximately linear (TCE, soil 1, K d = 0.0016; PCE, soil 1, K d = 0.0051; PCE, soil 2, K d = 0.0069) except for one case in which the best fitting was for the Langmuir isotherm (TCE, soil 2, K f = 0.6493 and S max = 0.0145). The results indicate low retardation coefficients (R) of TCE and PCE; however, somewhat lower values were obtained in batch compared to column experiments. In the column experiments with the presence of both contaminants, TCE influenced sorption of PCE, so that the R values for both compounds were almost two times higher. Non-significant differences in isotope compositions of TCE and PCE measured in the observation points (δ(13)C values within the range of -23.6 ÷ -24.3‰ and -26.3 ÷-27.7‰, respectively) indicate that biodegradation apparently is not an important process contributing to the natural attenuation of these contaminants in the studied sandy aquifer.

Application of Potential Phosphate-Solubilizing Bacteria and Organic Acids on Phosphate Solubilization from Phosphate Rock in Aerobic Rice

PubMed Central

Jusop, Shamshuddin; Naher, Umme Aminun; Othman, Radziah; Razi, Mohd Ismail

2013-01-01

A study was conducted at Universiti Putra Malaysia to determine the effect of phosphate-solubilizing bacteria (PSB) and organic acids (oxalic & malic) on phosphate (P) solubilization from phosphate rock (PR) and growth of aerobic rice. Four rates of each organic acid (0, 10, 20, and 30 mM), and PSB strain (Bacillus sp.) were applied to aerobic rice. Total bacterial populations, amount of P solubilization, P uptake, soil pH, and root morphology were determined. The results of the study showed significantly high P solubilization in PSB with organic acid treatments. Among the two organic acids, oxalic acid was found more effective compared to malic acid. Application of oxalic acid at 20 mM along with PSB16 significantly increased soluble soil P (28.39 mg kg−1), plant P uptake (0.78 P pot−1), and plant biomass (33.26 mg). Addition of organic acids with PSB and PR had no influence on soil pH during the planting period. A higher bacterial population was found in rhizosphere (8.78 log10 cfu g−1) compared to the nonrhizosphere and endosphere regions. The application of organic acids along with PSB enhanced soluble P in the soil solution, improved root growth, and increased plant biomass of aerobic rice seedlings without affecting soil pH. PMID:24288473

Science and Sandy: Lessons Learned

NASA Astrophysics Data System (ADS)

Werner, K.

2013-12-01

Following Hurricane Sandy's impact on the mid-Atlantic region, President Obama established a Task Force to '...ensure that the Federal Government continues to provide appropriate resources to support affected State, local, and tribal communities to improve the region's resilience, health, and prosperity by building for the future.' The author was detailed from NOAA to the Task Force between January and June 2013. As the Task Force and others began to take stock of the region's needs and develop plans to address them, many diverse approaches emerged from different areas of expertise including: infrastructure, management and construction, housing, public health, and others. Decision making in this environment was complex with many interests and variables to consider and balance. Although often relevant, science and technical expertise was not always at the forefront of this process. This talk describes the author's experience with the Sandy Task Force focusing on organizing scientific expertise to support the work of the Task Force. This includes a description of federal activity supporting Sandy recovery efforts, the role of the Task Force, and lessons learned from developing a science support function within the Task Force.

Fungicide dissipation and impact on metolachlor aerobic soil degradation and soil microbial dynamics.

PubMed

White, Paul M; Potter, Thomas L; Culbreath, Albert K

2010-02-15

Pesticides are typically applied as mixtures and or sequentially to soil and plants during crop production. A common scenario is herbicide application at planting followed by sequential fungicide applications post-emergence. Fungicides depending on their spectrum of activity may alter and impact soil microbial communities. Thus there is a potential to impact soil processes responsible for herbicide degradation. This may change herbicide efficacy and environmental fate characteristics. Our study objective was to determine the effects of 4 peanut fungicides, chlorothalonil (2,4,5,6-tetrachloro-1,3-benzenedicarbonitrile), tebuconazole (alpha-[2-(4-chlorophenyl)ethyl]-alpha-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol), flutriafol (alpha-(2-fluorophenyl)-alpha-(4-fluorophenyl)-1H-1,2,4-triazole-1-ethanol), and cyproconazole (alpha-(4-chlorophenyl)-alpha-(1-cyclopropylethyl)-1H-1,2,4-triazole-1-ethanol) on the dissipation kinetics of the herbicide, metolachlor (2-chloro-N-(6-ethyl-o-tolyl)-N-[(1RS)-2-methoxy-1-methylethyl]acetamide), and on the soil microbial community. This was done through laboratory incubation of field treated soil. Chlorothalonil significantly reduced metolachlor soil dissipation as compared to the non-treated control or soil treated with the other fungicides. Metolachlor DT(50) was 99 days for chlorothalonil-treated soil and 56, 45, 53, and 46 days for control, tebuconazole, flutriafol, and cyproconazole-treated soils, respectively. Significant reductions in predominant metolachlor metabolites, metolachlor ethane sulfonic acid (MESA) and metolachlor oxanilic acid (MOA), produced by oxidation of glutathione-metolachlor conjugates were also observed in chlorothalonil-treated soil. This suggested that the fungicide impacted soil glutathione-S-transferase (GST) activity. Fungicide DT(50) was 27-80 days but impacts on the soil microbial community as indicated by lipid biomarker analysis were minimal. Overall study results indicated that

Laboratory evaluation of dual-frequency multisensor capacitance probes to monitor soil water and salinity

USDA-ARS?s Scientific Manuscript database

Real-time information on salinity levels and transport of fertilizers are generally missing from soil profile knowledge bases. A dual-frequency multisensor capacitance probe (MCP) is now commercially available for sandy soils that simultaneously monitor volumetric soil water content (VWC, ') and sa...

Research Highlight: Water-extractable organic matter from sandy loam soils

USDA-ARS?s Scientific Manuscript database

Labile organic matter plays important roles in soil health and nutrient cycling because of its dynamic nature. Water-extractable organic matter is part of the soil labile organic matter. In an article recently published in Agricultural & Environmental Letters, researchers report on the level and na...

Micromorphological characteristics of sandy forest soils recently impacted by wildfires in Russia

NASA Astrophysics Data System (ADS)

Maksimova, Ekaterina; Abakumov, Evgeny

2017-04-01

Two fire-affected soils were studied using micromorphological methods. The objective of the paper is to assess and compare fire effects on the micropedological organisation of soils in a forest-steppe zone of central Russia (Volga Basin, Togliatti city). Samples were collected in the green zone of Togliatti city. The results showed that both soils were rich in quartz and feldspar. Mica was highly present in soils affected by surface fires, while calcium carbonates were identified in the soils affected by crown fires. The type of plasma is humus-clay, but the soil assemblage is plasma-silt with a prevalence of silt. Angular and subangular grains are the most dominant soil particulates. No evidence of intensive weathering was detected. There was a decrease in the porosity of soils affected by fires as a consequence of soil pores filled with ash and charcoal.

Ethnopedology and soil quality of bamboo (Bambusa sp.) based agroforestry system.

PubMed

Arun Jyoti, Nath; Lal, Rattan; Das, Ashesh Kumar

2015-07-15

It is widely recognized that farmers' hold important knowledge of folk soil classification for agricultural land for its uses, yet little has been studied for traditional agroforestry systems. This article explores the ethnopedology of bamboo (Bambusa sp.) based agroforestry system in North East India, and establishes the relationship of soil quality index (SQI) with bamboo productivity. The study revealed four basic folk soil (mati) types: kalo (black soil), lal (red soil), pathal (stony soil) and balu (sandy soil). Of these, lal mati soil was the most predominant soil type (~ 40%) in bamboo-based agroforestry system. Soil physio-chemical parameters were studied to validate the farmers' soil hierarchal classification and also to correlate with productivity of the bamboo stand. Farmers' hierarchal folk soil classification was consistent with the laboratory scientific analysis. Culm production (i.e. measure of productivity of bamboo) was the highest (27culmsclump(-1)) in kalo mati (black soil) and the lowest (19culmsclump(-1)) in balu mati (sandy soil). Linear correlation of individual soil quality parameter with bamboo productivity explained 16 to 49% of the variability. A multiple correlation of the best fitted linear soil quality parameter (soil organic carbon or SOC, water holding capacity or WHC, total nitrogen) with productivity improved explanatory power to 53%. Development of SQI from ten relevant soil quality parameters and its correlation with bamboo productivity explained the 64% of the variation and therefore, suggest SQI as the best determinant of bamboo yield. Data presented indicate that the kalo mati (black soil) is sustainable or sustainable with high input. However, the other three folk soil types (red, stony and sandy soil) are also sustainable but for other land uses. Therefore, ethnopedological studies may move beyond routine laboratory analysis and incorporate SQI for assessing the sustainability of land uses managed by the farmers'. Additional

EVALUATION OF RADON EMANATION FROM SOIL WITH VARYING MOISTURE CONTENT IN A SOIL CHAMBER

EPA Science Inventory

The paper describes measurements to quantitatively identify the extent to which moisture affects radon emanation and diffusive transport components of a sandy soil radon concentration gradient obtained in the EPA test chamber. The chamber (2X2X4 m long) was constructed to study t...

EPA COMPARES THREE SOIL-GAS SAMPLING SYSTEMS FOR VAPOR INTRUSION INVESTIGATIONS

EPA Science Inventory

This newsletter article summarizes the finding of "U.S. Environmental Protection Agency, Comparison of Geoprobe PRT, AMS GVP Soil-Gas Sampling Systems with Dedicated Vapor Probes in Sandy Soils at the Raymark Superfund Site, EPA/600/R-06/11, November 2006. "

Design of dry sand soil stratified sampler

NASA Astrophysics Data System (ADS)

Li, Erkang; Chen, Wei; Feng, Xiao; Liao, Hongbo; Liang, Xiaodong

2018-04-01

This paper presents a design of a stratified sampler for dry sand soil, which can be used for stratified sampling of loose sand under certain conditions. Our group designed the mechanical structure of a portable, single - person, dry sandy soil stratified sampler. We have set up a mathematical model for the sampler. It lays the foundation for further development of design research.

A New approach for evaluate a sandy soil infiltration to calculate the permeability

NASA Astrophysics Data System (ADS)

Mechergui, M. Mohamed; Latifa Dhaouadi, Ms

2016-04-01

10 sites were chosen in the four ha field of Research Regional Center of Oasis Agriculture in Deguache (Tozeur). The soil is homogeneous to the depth of 120 cm; with a sandy texture (60% big sand, 20% small sand 13% silt and 7% clay); with a mean bulk density equal to 1.43g/cm3 and with field capacity and welting point equal respectively to 11.9 and 6 %. The time duration for each infiltration essay lasted between 352 and 554 minutes. The number of observation points for each infiltration curve varies between 31 and 40. The shape of the infiltration curves observed in all sites is in part similar to what observed in literature (high increase with time of cumulative infiltration for a short time and then a linear increase of this parameter to a time varying between 122 to 197 minutes depending on the site) and then something special a slowdown in the cumulative infiltration to the end of the essay. The (F(t) / t 1/2 versus t 1/2) plotted curves showed two distinguished parts: A linear relation to the time varying between 122 and 197 minutes confirming the validity of Philips model and a second part showed a slowdown in the slope to a time varying between 231 and 347 minutes depending on the site and then drop down to the end of the essay. This is may be due to the rearrangement of particles after a long time of infiltration which led to a decrease in hydraulic conductivity. To improve the calculation of the saturated hydraulic conductivity, we choose only the part that is validated by Philips model, the linear part. The number of omitted points in the cumulative infiltration varies between 11 and 22 points. By this method, the saturated hydraulic conductivity varies between 1 and 3.72 m/day with a mean equal to 2.35. However the previous technique used gave a mean value equal to 2.07. The new method is accurate and gives better results of K and sorbtivity.

Water level response in back-barrier bays unchanged following Hurricane Sandy

USGS Publications Warehouse

Aretxabaleta, Alfredo L.; Butman, Bradford; Ganju, Neil K.

2014-01-01

On 28–30 October 2012, Hurricane Sandy caused severe flooding along portions of the northeast coast of the United States and cut new inlets across barrier islands in New Jersey and New York. About 30% of the 20 highest daily maximum water levels observed between 2007 and 2013 in Barnegat and Great South Bay occurred in 5 months following Hurricane Sandy. Hurricane Sandy provided a rare opportunity to determine whether extreme events alter systems protected by barrier islands, leaving the mainland more vulnerable to flooding. Comparisons between water levels before and after Hurricane Sandy at bay stations and an offshore station show no significant differences in the transfer of sea level fluctuations from offshore to either bay following Sandy. The post-Hurricane Sandy bay high water levels reflected offshore sea levels caused by winter storms, not by barrier island breaching or geomorphic changes within the bays.

Effects of biochar, compost and biochar-compost on growth and nutrient status of maize in two Mediterranean soils

NASA Astrophysics Data System (ADS)

Manolikaki, Ioanna; Diamadopoulos, Evan

2017-04-01

During the past years, studies have shown that biochar alone or combined with compost, has the potential to improve soil fertility and maize yield mostly on tropical soils whereas experiments on Mediterranean soils are rare. Therefore, the influence of biochar, compost and mixtures of the two, on maize (Zea mays L.) growth and nutrient status were investigated, in this study. Biochars were produced from 2 feedstocks: grape pomace (GP) and rice husks (RH) pyrolyzed at 300°C. Maize was grown for 30 days in a greenhouse pot trial on two Mediterranean soils amended with biochar or/with compost at application rates of 0% and 2% (w/w) (equivalent to 0 and 16 t ha-1) and N fertilization. Total aboveground dry matter yield of maize was significantly improved relative to the control for all organic amendments, with increases in yield 43-60.8%, in sandy loam soil, while, in loam soil a statistically significant increase of 70.6-81.3% was recorded for all the amendments apart from compost. Some morphological traits, such as aboveground height of plants, shoot diameter and belowground dry matter yield were significantly increased by the organic treatments. Aboveground concentration of P was significantly increased from 1.46 mg g-1 at control to 1.69 mg g-1 at 2% GP biochar in sandy loam soil, whereas GP biochar combined with compost gave an increase of 2.03 mg g-1 compared to control 1.23 mg g-1. K and Mn concentrations of above ground tissues were significantly increased only in sandy loam soil, while Fe in both soils. N concentration of aboveground tissues declined for all the amendments in loam soil and in sandy loam soil apart from compost amendment. Significant positive impacts of amended soils on nutrients uptake were observed in both soils as compared to the control related to the improved dry matter yield of plant. The current study demonstrated that maize production could be greatly improved by biochar and compost because of the nutrients they supply and their

Isolation of Acinetobacter from Soil and Water

PubMed Central

Baumann, Paul

1968-01-01

An enrichment culture procedure for isolating members of the genus Acinetobacter from soil and water is described. It involves the use of vigorously aerated mineral media at relative low pH, supplemented with acetate or other suitable carbon source and nitrate as nitrogen source. With this method, virtually all samples of soil and water yielded representatives of this genus. Semiquantitative comparisons of the numbers of Acinetobacter and of all bacteria capable of aerobic growth in a complex medium revealed that Acinetobacter constituted no less than 0.001% of the total heterotrophic aerobic population in soil and water and was one of the predominant organisms in some water samples. PMID:4874313

Health assessment for Lake Sandy Jo Landfill, Gary, Indiana, Region 5. CERCLIS No. IND980500524. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1985-11-21

The 50-acre Lake Sandy Jo Landfill is located in the Black Oak community (predominantly residential) of southwestern Gary in Lake County, Indiana. From about 1971 until about 1980, the lake was filled in with construction and demolition debris, municipal garbage, industrial wastes, hazardous materials, and possibly drummed wastes. These wastes are partly to completely exposed on the landfill surface. Surface soil, subsurface soil, surface water, sediment, and ground water show a variety of metal and organic chemical carcinogens. Toxic noncarcinogen priority pollutants found were chloromethane, copper, cyanide, lead, mercury, and silver. Inorganic soil levels found on the site for leadmore » and cadmium exceed levels of concern that would permit unrestricted use of the site. Remedial measures would be necessary before the site could be granted unrestricted use.« less

Spatial variability in the soil water content of a Mediterranean agroforestry system with high soil heterogeneity

NASA Astrophysics Data System (ADS)

Molina, Antonio Jaime; Llorens, Pilar; Aranda, Xavier; Savé, Robert; Biel, Carmen

2013-04-01

Variability of soil water content is known to increase with the size of spatial domain in which measurements are taken. At field scale, heterogeneity in soil, vegetation, topography, water input volume and management affects, among other factors, hydrologic plot behaviour under different mean soil water contents. The present work studies how the spatial variability of soil water content (SWC) is affected by soil type (texture, percentage of stones and the combination of them) in a timber-orientated plantation of cherry tree (Prunus avium) under Mediterranean climatic conditions. The experimental design is a randomized block one with 3 blocks * 4 treatments, based on two factors: irrigation (6 plots irrigated versus 6 plots not irrigated) and soil management (6 plots tillaged versus 6 plots not tillaged). SWC is continuously measured at 25, 50 and 100 cm depth with FDR sensors, located at two positions in each treatment: under tree influence and 2.5 m apart. This study presents the results of the monitoring during 2012 of the 24 sensors located at the 25 cm depth. In each of the measurement point, texture and percentage of stones were measured. Sandy-loam, sandy-clay-loam and loam textures were found together with a percentage of stones ranging from 20 to 70 %. The results indicated that the relationship between the daily mean SWC and its standard deviation, a common procedure used to study spatial variability, changed with texture, percentage of stones and the estimation of field capacity from the combination of both. Temporal stability analysis of SWC showed a clear pattern related to field capacity, with the measurement points of the sandy-loam texture and the high percentage of stones showing the maximun negative diference with the global mean. The high range in the mean relative difference observed (± 75 %), could indicate that the studied plot may be considered as a good field-laboratory to extrapolate results at higher spatial scales. Furthermore, the

Duripan effect on soil water availability: study case in North-Central Namibia

NASA Astrophysics Data System (ADS)

Prudat, Brice; Bloemertz, Lena; Kuhn, Nikolaus J.

2016-04-01

Soils with duripan and other hardpans are frequently disregarded for agriculture. However, in North-Central Namibia, farmers cultivate a type of sandy soil with a developing duripan at few decimetres of depth. This soil is particularly valuable for Pearl Millet cultivation during years with limited rainfall. Understanding the water dynamic and the role of the duripan in the soil moisture dynamic will improve livelihood and secure food production in North-Central Namibia, in Southern Angola and other areas in the world where similar soils appear. We recorded soil water content during five months at different depth in one of these sandy soil. The comparison of the recorded data with values calculated with models based on e.g. texture indicate that the duripan plays a very important role as water reservoir. Our results demonstrate that soils with duripans should not be disregarded for agricultural development, especially in context with irregular rainfall patterns. Understanding the role of duripans based on this study will thus help to anticipate and alleviate the effect of climate change in northern Namibia and other semi-arid regions, where similar soils occur.

Coastal ocean circulation during Hurricane Sandy

NASA Astrophysics Data System (ADS)

Miles, Travis; Seroka, Greg; Glenn, Scott

2017-09-01

Hurricane Sandy (2012) was the second costliest tropical cyclone to impact the United States and resulted in numerous lives lost due to its high winds and catastrophic storm surges. Despite its impacts little research has been performed on the circulation on the continental shelf as Sandy made landfall. In this study, integrated ocean observing assets and regional ocean modeling were used to investigate the coastal ocean response to Sandy's large wind field. Sandy's unique cross-shelf storm track, large size, and slow speed resulted in along-shelf wind stress over the coastal ocean for nearly 48 h before the eye made landfall in southern New Jersey. Over the first inertial period (˜18 h), this along-shelf wind stress drove onshore flow in the surface of the stratified continental shelf and initiated a two-layer downwelling circulation. During the remaining storm forcing period a bottom Ekman layer developed and the bottom Cold Pool was rapidly advected offshore ˜70 km. This offshore advection removed the bottom Cold Pool from the majority of the shallow continental shelf and limited ahead-of-eye-center sea surface temperature (SST) cooling, which has been observed in previous storms on the MAB such as Hurricane Irene (2011). This cross-shelf advective process has not been observed previously on continental shelves during tropical cyclones and highlights the need for combined ocean observing systems and regional modeling in order to further understand the range of coastal ocean responses to tropical cyclones.

The soil microbial community composition and soil microbial carbon uptake are more affected by soil type than by different vegetation types (C3 and C4 plants) and seasonal changes

NASA Astrophysics Data System (ADS)

Griselle Mellado Vazquez, Perla; Lange, Markus; Gleixner, Gerd

2016-04-01

This study investigates the influence of different vegetation types (C3 and C4 plants), soil type and seasonal changes on the soil microbial biomass, soil microbial community composition and soil microbial carbon (C) uptake. We collected soil samples in winter (non-growing season) and summer (growing season) in 2012 from an experimental site cropping C3 and C4 plants for 6 years on two different soil types (sandy and clayey). The amount of phospholipid fatty acids (PLFAs) and their compound-specific δ13C values were used to determined microbial biomass and the flow of C from plants to soil microorganisms, respectively. Higher microbial biomass was found in the growing season. The microbial community composition was mainly explained by soil type. Higher amounts of SOC were driving the predominance of G+ bacteria, actinobacteria and cyclic G- bacteria in sandy soils, whereas root biomass was significantly related to the increased proportions of G- bacteria in clayey soils. Plant-derived C in G- bacteria increased significantly in clayey soils in the growing season. This increase was positively and significantly driven by root biomass. Moreover, changes in plant-derived C among microbial groups pointed to specific capabilities of different microbial groups to decompose distinct sources of C. We concluded that soil texture and favorable growth conditions driven by rhizosphere interactions are the most important factors controlling the soil microbial community. Our results demonstrate that a change of C3 plants vs. C4 plants has only a minor effect on the soil microbial community. Thus, such experiments are well suited to investigate soil organic matter dynamics as they allow to trace the C flow from plants into the soil microbial community without changing the community abundance and composition.

Study on small-strain behaviours of methane hydrate sandy sediments using discrete element method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu Yanxin; Cheng Yipik; Xu Xiaomin

Methane hydrate bearing soil has attracted increasing interest as a potential energy resource where methane gas can be extracted from dissociating hydrate-bearing sediments. Seismic testing techniques have been applied extensively and in various ways, to detect the presence of hydrates, due to the fact that hydrates increase the stiffness of hydrate-bearing sediments. With the recognition of the limitations of laboratory and field tests, wave propagation modelling using Discrete Element Method (DEM) was conducted in this study in order to provide some particle-scale insights on the hydrate-bearing sandy sediment models with pore-filling and cementation hydrate distributions. The relationship between shear wavemore » velocity and hydrate saturation was established by both DEM simulations and analytical solutions. Obvious differences were observed in the dependence of wave velocity on hydrate saturation for these two cases. From the shear wave velocity measurement and particle-scale analysis, it was found that the small-strain mechanical properties of hydrate-bearing sandy sediments are governed by both the hydrate distribution patterns and hydrate saturation.« less

Toxicity of Fipronil in Mississippi Soil Types Against Reticulitermes flavipes (Isoptera: Rhinotermitidae)

Treesearch

J. E. Mulrooney; P. D. Gerard

2007-01-01

Three soils (a silt loam, loamy sand, sandy loam) found in Mississippi and pure silica sand were treated with fipronil and bioassayed using eastern subterranean termites, Reticulitermes flavipes. Soils were treated with aqueous solutions of Termidor (fipronil) at concentrations of 0, 0.12, 0.25,2.5, 5.0 and 20.0 ppm (wt AI: wt soil) that brought the soils to 15%...

Analysis of the inhibitory effects of chloropicrin fumigation on nitrification in various soil types.

PubMed

Yan, Dongdong; Wang, Qiuxia; Li, Yuan; Ouyang, Canbin; Guo, Meixia; Cao, Aocheng

2017-05-01

Chloropicrin retards the conversion of ammonia to nitrite during the nitrification process in soil. In our study, the dynamic effect of chloropicrin fumigation on soil nitrification was evaluated in five different soil types to identify relationships between soil properties and the effect of fumigation on nitrification. Chloropicrin significantly inhibited nitrification in all soils; however, the recovery of nitrification varied greatly between the soils. Following chloropicrin fumigation, nitrification recovered to the control level in all soils, except in the acidic Guangxi soil. Nitrification recovered faster in fumigated sandy loam Beijing soil than in the other four fumigated soils. Soil texture and pH were two important factors that influenced chloropicrin's inhibitory effect on nitrification. An S-shaped function was fitted to soil NO 3 - -N content to assess the nitrification recovery tendency in different soils. The time taken to reach maximum nitrification (t max ) ranged from 2.4 to 3.0 weeks in all unfumigated soils. Results demonstrated that t max was greater in all fumigated soils than in untreated soils. Correlation calculations showed that t max was strongly correlated to soil texture. The correlation analysis results indicated that the recovery rate of nitrification after chloropicrin fumigation is much faster in sandy loam soil than silty loam soil. Copyright © 2017. Published by Elsevier Ltd.

Regional prediction of carbon isotopes in soil carbonates for Asian dust source tracer

NASA Astrophysics Data System (ADS)

Chen, Bing; Cui, Xinjuan; Wang, Yaqiang

2016-10-01

Dust particles emitted from deserts and semi-arid lands in northern China cause particulate pollution that increases the burden of disease particularly for urban population in East Asia. The stable carbon isotopes (δ13C) of carbonates in soils and dust aerosols in northern China were investigated. We found that the δ13C of carbonates in surface soils in northern China showed clearly the negative correlation (R2 = 0.73) with Normalized Difference Vegetation Index (NDVI). Using Moderate Resolution Imaging Spectroradiometer (MODIS) satellite-derived NDVI, we predicted the regional distribution of δ13C of soil carbonates in deserts, sandy lands, and steppe areas. The predictions show the mean δ13C of -0.4 ± 0.7‰ in soil carbonates in Taklimakan Desert and Gobi Deserts, and the isotope values decrease to -3.3 ± 1.1‰ in sandy lands. The increase in vegetation coverage depletes 13C in soil carbonates, thus the steppe areas are predicted by the lowest δ13C levels (-8.1 ± 1.7‰). The measurements of atmospheric dust samples at eight sites showed that the Asian dust sources were well assigned by the 13C mapping in surface soils. Predicting 13C in large geographical areas with fine resolution offers a cost-effective tracer to monitor dust emissions from sandy lands and steppe areas which show an increasing role in Asian dust loading driven by climate change and human activities.

Nitrous oxide fluxes and soil oxygen dynamics of soil treated with cow urine

USDA-ARS?s Scientific Manuscript database

Ruminant urine deposition onto pastures creates hot-spots where emissions of nitrous oxide (N2O) are produced by aerobic and anaerobic microbial pathways. However, limited measurements of in situ soil oxygen (O2)-N2O relationships hinder the prediction of N2O emissions from urine-affected soil. This...

Sandy River Delta Habitat Restoration Project, Annual Report 2001.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelly, Virginia; Dobson, Robin L.

The Sandy River Delta is located at the confluence of the Sandy and Columbia Rivers, just east of Troutdale, Oregon. It comprises about 1,400 land acres north of Interstate 84, managed by the USDA Forest Service, and associated river banks managed by the Oregon Division of State Lands. Three islands, Gary, Flag and Catham, managed by Metro Greenspaces and the State of Oregon lie to the east, the Columbia River lies to the north and east, and the urbanized Portland metropolitan area lies to the west across the Sandy River. Sandy River Delta was historically a wooded, riparian wetland withmore » components of ponds, sloughs, bottomland woodland, oak woodland, prairie, and low and high elevation floodplain. It has been greatly altered by past agricultural practices and the Columbia River hydropower system. Restoration of historic landscape components is a primary goal for this land. The Forest Service is currently focusing on restoration of riparian forest and wetlands. Restoration of open upland areas (meadow/prairie) would follow substantial completion of the riparian and wetland restoration. The Sandy River Delta is a former pasture infested with reed canary grass, blackberry and thistle. The limited over story is native riparian species such as cottonwood and ash. The shrub and herbaceous layers are almost entirely non-native, invasive species. Native species have a difficult time naturally regenerating in the thick, competing reed canary grass, Himalayan blackberry and thistle. A system of drainage ditches installed by past owners drains water from historic wetlands. The original channel of the Sandy River was diked in the 1930's, and the river diverted into the ''Little Sandy River''. The original Sandy River channel has subsequently filled in and largely become a slough. The FS acquired approximately 1,400 acres Sandy River Delta (SRD) in 1991 from Reynolds Aluminum (via the Trust for Public Lands). The Delta had been grazed for many years but shortly after

CORRELATIONS BETWEEN PESTICIDE TRANSFORMATION RATE AND MICROBIAL RESPIRATION ACTIVITY IN SOIL OF DIFFERENT ECOSYSTEMS

EPA Science Inventory

Cecil sandy loam soils (ultisol) from forest (coniferous and deciduous), pasture, and arable ecosystems were sampled (0-10 cm) in the vicinity of Athens, GA, USA. Soil from each site was subdivided into three portions, consisting of untreated soil (control) as well as live and s...

Sandy beaches: state of the art of nematode ecology.

PubMed

Maria, Tatiana F; Vanaverbeke, Jan; Vanreusel, Ann; Esteves, André M

2016-01-01

In this review, we summarize existing knowledge of the ecology of sandy-beach nematodes, in relation to spatial distribution, food webs, pollution and climate change. We attempt to discuss spatial scale patterns (macro-, meso- and microscale) according to their degree of importance in structuring sandy-beach nematode assemblages. This review will provide a substantial background on current knowledge of sandy-beach nematodes, and can be used as a starting point to delineate further investigations in this field. Over decades, sandy beaches have been the scene of studies focusing on community and population ecology, both related to morphodynamic models. The combination of physical factors (e.g. grain size, tidal exposure) and biological interactions (e.g. trophic relationships) is responsible for the spatial distribution of nematodes. In other words, the physical factors are more important in structuring nematodes communities over large scale of distribution while biological interactions are largely important in finer-scale distributions. It has been accepted that biological interactions are assumed to be of minor importance because physical factors overshadow the biological interactions in sandy beach sediments; however, the most recent results from in-situ and ex-situ experimental investigations on behavior and biological factors on a microscale have shown promise for understanding the mechanisms underlying larger-scale patterns and processes. Besides nematodes are very promising organisms used to understand the effects of pollution and climate changes although these subjects are less studied in sandy beaches than distribution patterns.

Soil Fertility Gradient in the Restinga Ecosystem

NASA Astrophysics Data System (ADS)

América Castelar da Cunha, Joana; Casagrande, José Carlos; Soares, Marcio Roberto; Martins Bonilha, Rodolfo

2013-04-01

The restinga ecosystem (coastal plain vegetation) can be termed as a set of plant communities that suffer strong influenced by fluvial and marine factors and is characterized as an ecosystem of great biological diversity, therefore, represents areas of great importance in the context of ecological preservation. The degradation processes from many forms of anthropogenic disturbances that has taken place since the colonization of the country, made studies on the characterization and dynamics of soil fertility of these areas even more important in relation to the maintenance of its biodiversity and conservation. The sites studied were the Cardoso Island and Comprida Island, and in these, we analyzed four physiognomies, restinga, low restinga, dune and antedune (from continent to ocean). Chemical analyses were performed and soil salinity in these areas in depths 0-5; 0-10; 0-20; 20-40; 40-60 cm. In all soils the cationic exchange capacity was intimately associated with the concentration of soil organic matter, which makes this parameter essential to the maintenance of soil fertility of these areas; in more superficial layers (0-20 cm) there was an increase of pH and base saturation and decline of organic matter, aluminum saturation and cationic exchange capacity in the nearby sea, physiognomies what determines the existence of fertility gradient towards the continent-coast; restinga forests showed a chemical standard that is heavily marked by sandy texture, high degree of leaching, nutrient poverty, low base saturation, high saturation by aluminum and acidity, opposite conditions to soils of the dunes and antedunes, with the exception of sandy texture; despite the existence of a chemical gradient of fertility among the physiognomies studied it is possible to determine the soil acts more strongly as a physical support than as provider of fertility; as for salinity, soil collected in Cardoso Island did not present salinity in any depth, a fact which can be explained due

Evaluation of alternative landfill cover soils for attenuating hydrogen sulfide from construction and demolition (C&D) debris landfills.

PubMed

Plaza, Cristine; Xu, Qiyong; Townsend, Timothy; Bitton, Gabriel; Booth, Matthew

2007-08-01

Hydrogen sulfide (H(2)S) generated from C&D debris landfills has emerged as a major environmental concern due to odor problems and possible health impacts to landfill employees and surrounding residents. Research was performed to evaluate the performance of various cover materials as control measures for H(2)S emissions from C&D debris landfills. Twelve laboratory-scale simulated landfill columns containing gypsum drywall were operated under anaerobic conditions to promote H(2)S production. Five different cover materials were placed on top of the waste inside duplicate columns: (1) sandy soil, (2) sandy soil amended with lime, (3) clayey soil, (4) fine concrete (particle size less than 2.5 cm), and (5) coarse concrete (particle size greater than 2.5 cm). No cover was placed on two of the columns, which were used as controls. H(2)S concentrations measured from the middle of the waste layer ranged from 50,000 to 150,000 ppm. The different cover materials demonstrated varying H(2)S removal efficiencies. The sandy soil amended with lime and the fine concrete were the most effective for the control of H(2)S emissions. Both materials exhibited reduction efficiencies greater than 99%. The clayey and sandy soils exhibited lower reduction efficiencies, with average removal efficiencies of 65% and 30%, respectively. The coarse concrete was found to be the least efficient material as a result of its large particle size.

Interactions between soil texture and placement of dairy slurry application: II. Leaching of phosphorus forms.

PubMed

Glaesner, Nadia; Kjaergaard, Charlotte; Rubaek, Gitte H; Magid, Jakob

2011-01-01

Managing phosphorus (P) losses in soil leachate folllowing land application of manure is key to curbing eutrophication in many regions. We compared P leaching from columns of variably textured, intact soils (20 cm diam., 20 cm high) subjected to surface application or injection of dairy cattle (Bos taurus L.) manure slurry. Surface application of slurry increased P leaching losses relative to baseline losses, but losses declined with increasing active flow volume. After elution of one pore volume, leaching averaged 0.54 kg P ha(-1) from the loam, 0.38 kg P ha(-1) from the sandy loam, and 0.22 kg P ha(-1) from the loamy sand following surface application. Injection decreased leaching of all P forms compared with surface application by an average of 0.26 kg P ha(-1) in loam and 0.23 kg P ha(-1) in sandy loam, but only by 0.03 kg P ha(-1) in loamy sand. Lower leaching losses were attributed to physical retention of particulate P and dissolved organic P, caused by placing slurry away from active flow paths in the fine-textured soil columns, as well as to chemical retention of dissolved inorganic P, caused by better contact between slurry P and soil adsorption sites. Dissolved organic P was less retained in soil after slurry application than other P forms. On these soils with low to intermediate P status, slurry injection lowered P leaching losses from clay-rich soil, but not from the sandy soils, highlighting the importance of soil texture in manageing P losses following slurry application.

ON-SITE ENGINEERING REPORT OF THE SLURRY-PHASE BIOLOGICAL REACTOR FOR PILOT-SCALE TESTING ON CONTAMINATED SOIL

EPA Science Inventory

The performance of pilot-scale bioslurry treatment on creosote-contaminated soil was evaluated. Five reactors containing 66 L of slurry (30% soil by weight), were operated in parallel. The soil was a sandy soil with minor gravel content. The pilot-scale phase utilized an inoculum...

Climatic thresholds for pedogenic iron oxides under aerobic conditions: Processes and their significance in paleoclimate reconstruction

NASA Astrophysics Data System (ADS)

Long, Xiaoyong; Ji, Junfeng; Barrón, Vidal; Torrent, José

2016-10-01

Iron oxides are widely distributed across the surface of the Earth as a result of the aerobic weathering of primary Fe-bearing minerals. Pedogenic iron oxides which consist mainly of hematite (Hm), goethite (Gt), maghemite (Mgh), are often concentrated synchronously in aerobic soils under low to moderate rainfall regimes. Magnetic susceptibility (χ) and redness, which respectively reflect the content of Mgh and Hm in soils, are considered reasonable pedogenic and climatic indicators in soil taxonomy and paleorainfall reconstruction. However, under high rainfall regimes, the grain growth of Mgh and transformation to Hm, combined with the prior formation of Gt under conditions of high relative humidity (RH), can result in magnetic reduction and dramatic yellowing of soils and sediments, which explains the existence of rainfall thresholds for Mgh and Hm at a large scale even before the pedogenic environment turns anaerobic. In order to capture the rainfall thresholds for Mgh and Hm occurring under aerobic conditions, we explored a tropical transect across a granitic region where the soil color turned from red to yellow under a wide rainfall range of 900-2200 mm/yr and a corresponding mean annual RH range of 77%-85%. We observed a lower rainfall threshold of ∼1500 mm/yr and a corresponding RH ∼80% for Mgh and Hm along this transect, as well as a higher rainfall threshold of ∼1700 mm/yr and a corresponding RH of ∼81% for Gt and total pedogenic iron oxides (citrate/bicarbonate/dithionite-extractable Fe, Fed). Cross-referencing with comparable studies in temperate and subtropical regions, we noted that the rainfall or RH thresholds for Fed and Hm or Mgh likewise increase with temperature. Moreover, the different thresholds for total and individual iron oxide phase indicates that a negative correlation between chemical weathering intensity and redness or χ in sediment sequences can occur under the prevalent climate regime just between their thresholds. Finally

On-farm treatment of dairy soiled water using aerobic woodchip filters.

PubMed

Ruane, Eimear M; Murphy, Paul N C; Healy, Mark G; French, Padraig; Rodgers, Michael

2011-12-15

Dairy soiled water (DSW) is produced on dairy farms through the washing-down of milking parlours and holding areas, and is generally applied to land. However, there is a risk of nutrient loss to surface and ground waters from land application. The aim of this study was to use aerobic woodchip filters to remove organic matter, suspended solids (SS) and nutrients from DSW. This novel treatment method would allow the re-use of the final effluent from the woodchip filters to wash down yards, thereby reducing water usage and environmental risks associated with land spreading. Three replicate 100 m(2) farm-scale woodchip filters, each 1 m deep, were constructed and operated to treat DSW from 300 cows over an 11-month study duration. The filters were loaded at a hydraulic loading rate of 30 L m(-2) d(-1), applied in four doses through a network of pipes on the filter surface. Average influent concentrations of chemical oxygen demand (COD), SS and total nitrogen (TN) of 5750 ± 1441 mg L(-1), 602 ± 303 mg L(-1) and 357 ± 100 mg L(-1), respectively, were reduced by 66, 86 and 57% in the filters. Effluent nutrient concentrations remained relatively stable over the study period, indicating the effectiveness of the filter despite increasing and/or fluctuating influent concentrations. Woodchip filters are a low cost, minimal maintenance treatment system, using a renewable resource that can be easily integrated into existing farm infrastructure. Copyright © 2011 Elsevier Ltd. All rights reserved.

Long-term grazing effects on vegetation characteristics and soil properties in a semiarid grassland, northern China.

PubMed

Zhang, Jing; Zuo, Xiaoan; Zhou, Xin; Lv, Peng; Lian, Jie; Yue, Xiyuan

2017-05-01

Understanding the responses of vegetation characteristics and soil properties to grazing disturbance is useful for grassland ecosystem restoration and management in semiarid areas. Here, we examined the effects of long-term grazing on vegetation characteristics, soil properties, and their relationships across four grassland types (meadow, Stipa steppe, scattered tree grassland, and sandy grassland) in the Horqin grassland, northern China. Our results showed that grazing greatly decreased vegetation cover, aboveground plant biomass, and root biomass in all four grassland types. Plant cover and aboveground biomass of perennials were decreased by grazing in all four grasslands, whereas grazing increased the cover and biomass of shrubs in Stipa steppe and of annuals in scattered tree grassland. Grazing decreased soil carbon and nitrogen content in Stipa steppe and scattered tree grassland, whereas soil bulk density showed the opposite trend. Long-term grazing significantly decreased soil pH and electrical conductivity (EC) in annual-dominated sandy grassland. Soil moisture in fenced and grazed grasslands decreased in the following order of meadow, Stipa steppe, scattered tree grassland, and sandy grassland. Correlation analyses showed that aboveground plant biomass was significantly positively associated with the soil carbon and nitrogen content in grazed and fenced grasslands. Species richness was significantly positively correlated with soil bulk density, moisture, EC, and pH in fenced grasslands, but no relationship was detected in grazed grasslands. These results suggest that the soil carbon and nitrogen content significantly maintains ecosystem function in both fenced and grazed grasslands. However, grazing may eliminate the association of species richness with soil properties in semiarid grasslands.

Persistence and mobility of nitrofen (niclofen, TOK) in mineral and organic soils.

PubMed

Murty, A S; Miles, J R; Tu, C M

1982-01-01

Residues of nitrofen in farm soils, persistence of nitrofen in field microplots, mobility of nitrofen in natural soils and the role of microbial flora in its degradation were studied. Muck soils from vegetable farms in southwestern Ontario contained up to 35 ppm nitrofen in mid-season (August), which decreased to 18 ppm by October. The herbicide was less persistent in sand than in muck. Degradation was slightly faster in sand and muck soils receiving two sprays, than in those sprayed once. From an initial deposit of ca. 2 and 10 ppm resp., in sand and muck field microplots, ca. 2 and 15% persisted after 16 wk. Leaching of nitrofen by water through sand was negligible, and it was even more strongly adsorbed onto organic soil. Natural microbial flora seemed to play an important role in the degradation of nitrofen in soil. Ca. 15 and 38% resp., of the initial concentration persisted in natural sandy loam and muck 16 wk after treatment at 10 ppm, whereas about 94 and 82% resp., persisted in sterilized sandy loam and muck at the same period.

Geochemistry Of Lead In Contaminated Soils: Effects Of Soil Physico-Chemical Properties

NASA Astrophysics Data System (ADS)

Saminathan, S.; Sarkar, D.; Datta, R.; Andra, S. P.

2006-05-01

Lead (Pb) is an environmental contaminant with proven human health effects. When assessing human health risks associated with Pb, one of the most common exposure pathways typically evaluated is soil ingestion by children. However, bioaccessibility of Pb primarily depends on the solubility and hence, the geochemical form of Pb, which in turn is a function of site specific soil chemistry. Certain fractions of ingested soil-Pb may not dissociate during digestion in the gastro-intestinal tract, and hence, may not be available for transport across the intestinal membrane. Therefore, this study is being currently performed to assess the geochemical forms and bioaccessibility of Pb in soils with varying physico-chemical properties. In order to elucidate the level of Pb that can be ingested and assimilated by humans, an in-vitro model that simulates the physiological conditions of the human digestive system has been developed and is being used in this study. Four different types of soils from the Immokalee (an acid sandy soil with minimal Pb retention potential), Millhopper (a sandy loam with high Fe/Al content), Pahokee (a muck soil with more than 80% soil organic matter), and Tobosa series (an alkaline soil with high clay content) were artificially contaminated with Pb as lead nitrate at the rate equivalent to 0, 400, 800, and 1200 mg/kg dry soil. Analysis of soils by a sequential extraction method at time zero (immediately after spiking) showed that Immokalee and Millhopper soils had the highest amount of Pb in exchangeable form, whereas Pahokee and Tobosa soils had higher percentages of carbonate-bound and Fe/Al-bound Pb. The results of in-vitro experiment at time zero showed that majority of Pb was dissolved in the acidic stomach environment in Immokalee, Millhopper, and Tobosa, whereas it was in the intestinal phase in Pahokee soils. Because the soil system is not in equilibrium at time zero, the effect of soil properties on Pb geochemistry is not clear as yet. The

Influences of composted hazelnut husk on some physical properties of soils.

PubMed

Zeytin, Serhat; Baran, Abdullah

2003-07-01

Some physical properties of clay loam and sandy loam soils amended with hazelnut husk (HH) were investigated. HH collected from hazelnut trees were dried, ground and composted for four months. Before use the composted material obtained was separated to three different aggregate sizes, smaller than 0.84 mm, 0.84-2.38 mm and bigger than 2.38 mm. Then these fractions were mixed with soil samples, at 0%, 1%, 2%, 4% and 8% by weight. Huzelnut husk compost-soil mixtures were placed to plastic pots and kept in an incubator at 25+/-5 degrees C for 45 and 90 days. At the end of incubation periods, water stable aggregate (WSA), hydraulic conductivity, total porosity, aeration porosity and macro- and micro-pore percentages of the mixtures were determined. Results obtained showed that composted HH increased the WSA, hydraulic conductivity, total porosity and macro-pore percentage in both clay loam and sandy loam soils depending on the incubation time and aggregate sizes.

Psammochthoniidae n. fam., a paedomorphic family of oribatid mites (Oribatida: Enarthronota) from sandy soil in Thailand, Brazil and the U.S.A.

PubMed

Fuangarworn, Marut; Norton, Roy A

2013-01-01

A new genus and species of enarthronote oribatid mite, Psammochthonius kethleyi n.g., n. sp., is described and illustrated based on adult and immature specimens collected from coastal sandy soil in Thailand (Phangnga), Brazil (SAo Paulo) and the U.S.A. (Mississippi). Analysis shows that it is a member of Hypochthonioidea, but not of any named family, so the monobasic family Psammochthoniidae n. fain. is proposed. Traits that are unique among hypochthonioid mites include an adult body length under 250 microm, a functionally trichoid body form (postpedal flexing), strong lateral displacement of setae in row e, which insert on a unique form of transverse scissure, subcapitular stenarthry, leg IV vestiges and a possible precocious genital swelling in the larva, apparent absence of an anal segment, and a highly regressed leg setation. The latter two, and some other traits that were previously unknown in Hypochthonioidea, suggest that Psammochthoniidae represents the first clearly paedomorphic lineage in this diverse superfamily. Like all other known hypochthonioid mites, P. kethleyi appears to be thelytokous.

Fluensulfone sorption and mobility as affected by soil type.

PubMed

Morris, Kelly A; Li, Xiao; Langston, David B; Davis, Richard F; Timper, Patricia; Grey, Timothy L

2018-02-01

Fluensulfone is a fluoroalkenyl chemical with activity against multiple genera of plant-parasitic nematodes. The adsorption, desorption, and mobility of fluensulfone were evaluated on multiple soils from the USA in laboratory and column experiments. Adsorption data regressed to the logarithmic Freundlich equation resulted in isotherm values of 1.24 to 3.28. Soil adsorption of fluensulfone correlated positively with organic matter (0.67) and clay (0.34), but negatively with sand (-0.54). Fluensulfone soil desorption correlated to pH (0.38) and cation exchange capacity (0.44). Fluensulfone desorption from Arredondo sand soil was 26%, and from other soils ranged from 43 to 70%. In mobility experiments, fluensulfone in the leachate peaked at 3 h, gradually declining and becoming undetectable after 9 h. Recovery from leachate was 45% of the initial fluensulfone applied to the soil surface. In separate experiments, 30-cm-long soil columns were saturated with 1 L of water, and then segregated into three 10-cm sections. Fluensulfone recovery was 41, 34, 29, and 13% in Chualar sandy loam, Arredondo sand, Greenville sandy clay loam, and Tifton loamy sand, respectively, in the top 10-cm section. Data indicated that soil organic matter and clay contents will affect sorption, mobility, and dissipation of fluensulfone. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Isotope fractionation of sandy-soil water during evaporation - an experimental study.

PubMed

Rao, Wen-Bo; Han, Liang-Feng; Tan, Hong-Bing; Wang, Shuai

2017-06-01

Soil samples containing water with known stable isotopic compositions were prepared. The soil water was recovered by using vacuum/heat distillation. The experiments were held under different conditions to control rates of water evaporation and water recovery. Recoveries, δ 18 O and δ 2 H values of the soil water were determined. Analyses of the data using a Rayleigh distillation model indicate that under the experimental conditions only loosely bound water is extractable in cases where the recovery is smaller than 100 %. Due to isotopic exchange between vapour and remaining water in the micro channels or capillaries of the soil matrix, isotopic fractionation may take place under near-equilibrium conditions. This causes the observed relationship between δ 2 H and δ 18 O of the extracted water samples to have a slope close to 8. The results of this study may indicate that, in arid zones when soil that initially contains water dries out, the slope of the relationship between δ 2 H and δ 18 O values should be close to 8. Thus, a smaller slope, as observed by some groundwater and soil water samples in arid zones, may be caused by evaporation of water before the water has entered the unsaturated zone.

Dissipation of phenanthrene and pyrene at the aerobic-anaerobic soil interface: differentiation induced by the rhizosphere of PAH-tolerant and PAH-sensitive rice (Oryza sativa L.) cultivars.

PubMed

He, Yan; Xia, Wen; Li, Xinfeng; Lin, Jiajiang; Wu, Jianjun; Xu, Jianming

2015-03-01

A pot experiment was conducted to reveal the removal of two polycyclic aromatic hydrocarbons (PAHs) (phenanthrene, PHE, and pyrene, PYR) during rice cultivation in a paddy field. The rhizosphere effect on facilitating dissipation of PAHs varied simultaneously as a function of soil properties, PAH types, cultivation time, and genotypes within rice cultivars, with differences performed for PYR but not PHE. Changes in soil PLFA profiles evidenced that the growth of rice roots modified the dominant species within rhizosphere microbial communities and induced a selective enrichment of Gram-negative aerobic bacteria capable of degrading, thereby resulting in the differentiated dissipation of PYR. While the insignificant differences in PHE dissipation might be attributed to its higher solubility and availability under flooded condition that concealed the differences in improvement of bioavailability for microorganisms between rhizosphere and non-rhizosphere, and between both soils and both rice cultivars. Our findings illustrate that the removal of PAHs in paddy soils was more complex relative to those in dryland soils. This was possibly due to the specialty of rice roots for oxygen secretion that provides development of redox heterogeneous microbial habitats at root-soil interface under flooded condition.

Soil physical effects on longleaf pine performance in the West Gulf Coastal Plain

Treesearch

Mary Anne S. Sayer; James D. Haywood; Shi-Jean Susana Sung

2015-01-01

We summarize 8 years of soil physical property responses to herbicide manipulation of the understory in two young longleaf pine stands growing on either Ruston fine sandy loam or Beauregard silt loam soils. We also describe relationships between pine sapling vigor and the soil physical environment across a 3-year period on the Ruston soil and a 2-year period on the...

Impact of glycerin and lignosulfonate on biodegradation of high explosives in soil.

PubMed

Won, Jongho; Borden, Robert C

2016-11-01

Soil microcosms were constructed and monitored to evaluate the impact of substrate addition and transient aerobic and anaerobic conditions on TNT, RDX and HMX biodegradation in grenade range soils. While TNT was rapidly biodegraded under both aerobic and anaerobic conditions with and without organic substrate, substantial biodegradation of RDX, HMX, and RDX daughter products was not observed under aerobic conditions. However, RDX and HMX were significantly biodegraded under anaerobic conditions, without accumulation of TNT or RDX daughter products (2-ADNT, 4-ADNT, MNX, DNX, and TNX). In separate microcosms containing grenade range soil, glycerin and lignosulfonate addition enhanced oxygen consumption, increasing the consumption rate >200% compared to untreated soils. Mathematical model simulations indicate that oxygen consumption rates of 5 to 20g/m 3 /d can be achieved with reasonable amendment loading rates. These results indicate that glycerin and lignosulfonate can be potentially used to stimulate RDX and HMX biodegradation by increasing oxygen consumption rates in soil. Copyright © 2016 Elsevier B.V. All rights reserved.

Laboratory study on leachability of five herbicides in South Australian soils.

PubMed

Ying, G G; Williams, B

2000-03-01

Norflurazon, oxadiazon, oxyfluorfen, trifluralin and simazine are herbicides widely used in the vineyards of the Barossa Valley, South Australia. The leaching behaviour of norflurazon, oxadiazon, oxyfluorfen and trifluralin was investigated on four key soils in the Barossa Valley. Leaching potential on packed soil columns and actual mobility using intact soil columns were investigated. On the packed soil columns, norflurazon was the most leachable herbicide. More of the herbicides were detected in the leachates from the sandy soils (Mountadam and Nuriootpa) than from the clayey soils (Lyndoch and Tanunda). Organic matter is generally low in soils in the Barossa region. Porosity and saturated conductivity significantly affect herbicide movement and in the sandy Mountadam and Nuriootpa soils, the water flux is greater than for the higher clay content Lyndoch and Tanunda soils. Increasing the time interval between herbicide application and the incidence of "rainfall" reduced the amounts of herbicides found in the leachates. The use of intact soil columns and including simazine for comparison showed that both norflurazon and simazine were present in the leachates. Simazine was the first herbicide to appear in leachates. Sectioning of the intact soil columns after leaching clearly demonstrated that norflurazon and simazine reached the bottom of the soil columns for all soils studied. Greater amounts of norflurazon were retained in the soil columns compared with simazine. The other herbicides were mostly retained in the initial sections of the soil columns.

Shoreface response and recovery to Hurricane Sandy: Fire Island, NY

USGS Publications Warehouse

Nelson, Timothy R.; Hapke, Cheryl J.; Wang, Ping; Rosati, Julie D.; Cheng, Jun

2015-01-01

The shoreface of Fire Island was extensively modified by Hurricane Sandy and subsequent storms in the following winter months. The changes were evaluated using various morphometrics of the shoreface from four bathymetric surveys, one prior to Hurricane Sandy, and three over the course of twenty months following Sandy. The datasets show that the nearshore bar system moved offshore to deeper water depths following Hurricane Sandy with volume lost from the subaerial beach and surfzone. Following the offshore shift, the nearshore bar system increased in size, the trough deepened, and there has been gradual landward movement of the nearshore bar. The steepening of the upper shoreface, landward translation of the profile, and loss of sediment is indicative of barrier island transgression.

Rapid Consumption of Low Concentrations of Methyl Bromide by Soil Bacteria

PubMed Central

Hines, Mark E.; Crill, Patrick M.; Varner, Ruth K.; Talbot, Robert W.; Shorter, Joanne H.; Kolb, Charles E.; Harriss, Robert C.

1998-01-01

A dynamic dilution system for producing low mixing ratios of methyl bromide (MeBr) and a sensitive analytical technique were used to study the uptake of MeBr by various soils. MeBr was removed within minutes from vials incubated with soils and ∼10 parts per billion by volume of MeBr. Killed controls did not consume MeBr, and a mixture of the broad-spectrum antibiotics chloramphenicol and tetracycline inhibited MeBr uptake by 98%, indicating that all of the uptake of MeBr was biological and by bacteria. Temperature optima for MeBr uptake suggested a biological sink, yet soil moisture and temperature optima varied for different soils, implying that MeBr consumption activity by soil bacteria is diverse. The eucaryotic antibiotic cycloheximide had no effect on MeBr uptake, indicating that soil fungi were not involved in MeBr removal. MeBr consumption did not occur anaerobically. A dynamic flowthrough vial system was used to incubate soils at MeBr mixing ratios as low as those found in the remote atmosphere (5 to 15 parts per trillion by volume [pptv]). Soils consumed MeBr at all mixing ratios tested. Temperate forest and grassy lawn soils consumed MeBr most rapidly (rate constant [k] = 0.5 min−1), yet sandy temperate, boreal, and tropical forest soils also readily consumed MeBr. Amendments of CH4 up to 5% had no effect on MeBr uptake even at CH4:MeBr ratios of 107, and depth profiles of MeBr and CH4 consumption exhibited very different vertical rate optima, suggesting that methanotrophic bacteria, like those presently in culture, do not utilize MeBr when it is at atmospheric mixing ratios. Data acquired with gas flux chambers in the field demonstrated the very rapid in situ consumption of MeBr by soils. Uptake of MeBr at mixing ratios found in the remote atmosphere occurs via aerobic bacterial activity, displays first-order kinetics at mixing ratios from 5 pptv to ∼1 part per million per volume, and is rapid enough to account for 25% of the global annual loss of

Biotic and abiotic degradation of CL-20 and RDX in soils.

PubMed

Crocker, Fiona H; Thompson, Karen T; Szecsody, James E; Fredrickson, Herbert L

2005-01-01

The caged cyclic nitramine 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) is a new explosive that has the potential to replace existing military explosives, but little is known about its environmental toxicity, transport, and fate. We quantified and compared the aerobic environmental fate of CL-20 to the widely used cyclic nitramine explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in surface and subsurface soil microcosms. Soil-free controls and biologically attenuated soil controls were used to separate abiotic processes from biologically mediated processes. Both abiotic and biological processes significantly degraded CL-20 in all soils examined. Apparent abiotic, first-order degradation rates (k) for CL-20 were not significantly different between soil-free controls (0.018 < k < 0.030 d(-1)) and biologically attenuated soil controls (0.003 < k < 0.277 d(-1)). The addition of glucose to biologically active soil microcosms significantly increased CL-20 degradation rates (0.068 < k < 1.22 d(-1)). Extents of mineralization of (14)C-CL-20 to (14)CO(2) in biologically active soil microcosms were 41.1 to 55.7%, indicating that the CL-20 cage was broken, since all carbons are part of the heterocyclic cage. Under aerobic conditions, abiotic degradation rates of RDX were generally slower (0 < k < 0.032 d(-1)) than abiotic CL-20 degradation rates. In biologically active soil microcosms amended with glucose aerobic RDX degradation rates varied between 0.010 and 0.474 d(-1). Biodegradation was a key factor in determining the environmental fate of RDX, while a combination of biotic and abiotic processes was important with CL-20. Our data suggest that CL-20 should be less recalcitrant than RDX in aerobic soils.

Bioremediation trial on aged PCB-polluted soils--a bench study in Iceland.

PubMed

Lehtinen, Taru; Mikkonen, Anu; Sigfusson, Bergur; Ólafsdóttir, Kristín; Ragnarsdóttir, Kristín Vala; Guicharnaud, Rannveig

2014-02-01

Polychlorinated biphenyls (PCBs) pose a threat to the environment due to their high adsorption capacity to soil organic matter, stability and low reactivity, low water solubility, toxicity and ability to bioaccumulate. With Icelandic soils, research on contamination issues has been very limited and no data has been reported either on PCB degradation potential or rate. The goals of this research were to assess the bioavailability of aged PCBs in the soils of the old North Atlantic Treaty Organization facility in Keflavík, Iceland and to find the best biostimulation method to decrease the pollution. The effectiveness of different biostimulation additives (N fertiliser, white clover and pine needles) at different temperatures (10 and 30 °C) and oxygen levels (aerobic and anaerobic) were tested. PCB bioavailability to soil fauna was assessed with earthworms (Eisenia foetida). PCBs were bioavailable to earthworms (bioaccumulation factor 0.89 and 0.82 for earthworms in 12.5 ppm PCB soil and in 25 ppm PCB soil, respectively), with less chlorinated congeners showing higher bioaccumulation factors than highly chlorinated congeners. Biostimulation with pine needles at 10 °C under aerobic conditions resulted in nearly 38 % degradation of total PCBs after 2 months of incubation. Detection of the aerobic PCB degrading bphA gene supports the indigenous capability of the soils to aerobically degrade PCBs. Further research on field scale biostimulation trials with pine needles in cold environments is recommended in order to optimise the method for onsite remediation.

Ecological risk assessment: influence of texture on background concentration of microelements in soils of Russia.

NASA Astrophysics Data System (ADS)

Beketskaya, Olga

2010-05-01

, organic matter content, concentration of microelements and pH value. On the basis of this data base massive of data for Forest-steppe and Steppe regions was create, which was divided by texture. For all data statistics method was done and was calculated maximum level natural microelements content for soils with different texture (?+3*δ). As a result of our statistic calculation we got middle and the top limit of background concentration of microelements in sandy and clay soils (conditional border - sandy loam) of two regions. We showed, that for all territory of European part of Russia and for Forest-steppe and Steppe regions separately middle content and maximum level natural microelements concentrations (?+3*σ) are higher in clay soils, rather then in sandy soils. Data characterizing soils, in different regions, of similar texture differs less than the data collected for sandy and clay soils of the same region. After all this calculation we can notice, that data of middle and top limit of background microelements concentration in soils, based on statistic method, can be used in the aim of ecological risk assessment. Using offered method allow to calculate top limit of background concentration for sandy and clay soils for large-scale geographic regions, exceeding which will be evidence of anthropogenic contamination of soil.

Effects of biosolid amendment on populations of Meloidogyne hapla and soils with different textures and pHs.

PubMed

Mennan, Sevilhan; Melakeberhan, Haddish

2010-09-01

Temperate vegetable and nursery industries face significant challenges in managing Meloidogyne hapla, a plant-parasite for which few resistant cultivars and/or viable alternatives to methyl bromide exist. N-Viro Soil(R) (NVS), an alkaline-stabilized biosolid product, has soil nutrition enrichment capacity and potential for plant-parasitic nematode suppression. In three sets of experiments, we investigated the effects of NVS on M. hapla populations from Rhode Island (RI), Connecticut (CT), New York, Geneva (NYG) and Lyndonville (NYL), and Michigan (MI), and growth of tomato cv 'Rutgers' in five soils commonly used for vegetable and nursery crop production in the Great Lakes Region of the USA. Either 0 (control) or 600 eggs/100 cm(3) of soil per M. hapla population were added in all experiments. In the first set, NVS was applied at rates of 0, 1, 2 and 4 g/100 cm(3) of sandy loam soil (pH 7) and resulted in variable responses on the numbers of nematodes recovered and plant growth at 30 and 90 days (25+/-2 degrees C); however, the 2g NVS treatment consistently increased plant growth. Either 0 or 2 NVS/100 cm(3) were applied to a coarse loamy (pH 4.5) and sandy loam (pH 8, second set of experiments), and muck (pH 5.5), loamy sand (pH 7.1) and sandy loam (pH 7.5, third set of experiments) soils and experiments terminated four weeks after nematode inoculation. Across experiments, the effect of NVS on the M. hapla populations varied. Generally nematode infection decreased plant growth. NVS increased soil pH the most in muck and the least in sandy loam soil. The most consistent interaction effects of NVS*soil, NVS*M. hapla, soil*M. hapla and/or NVS*soil*M. hapla across the experiments indicate that NVS affects M. hapla populations in different ways in different soil types, suggesting that NVS application is likely to be site-specific. These findings further provide basis that may potentially explain reports of variable effects of NVS on nematodes and how future studies may

Dynamics of the Entomogenous Nematode Steinernema feltiae Applied to Soil with and without Nematicide Treatment

PubMed Central

Ishibashi, N.; Kondo, E.

1987-01-01

The dynamics of Steinernema feltiae strain DD-136 in soils with different fauna was investigated to determine the best method for the biological control of soil insects. Infective juveniles (J3) were applied to field plots with and without 1,3-D (Telone II) fumigation. Recovery of J3 and changes in native nematode fauna were monitored until the applied J3 were no longer recovered by Baermann funnel (BF). Recovery of J3 by BF or by a two-step extraction procedure from steam-sterilized or nonsterilized sandy or silty soil with different fauna was investigated. More DD-136 J3 were recovered from the 1,3-D treated soil than from nontreated soil, while native nematodes in the treated soil fluctuated more with the addition of DD-136 than those in nontreated soil. The J3 persisted longer in silty than in sandy soils. The inundative soil application of DD-136 increased native rhabditids and decreased plant-parasitic nematodes. DD-136 in chemically treated soil not only effectively attacked the invading soil insect pests but also suppressed the recovery of plant nematodes. PMID:19290163

Soil surface disturbances in cold deserts: Effects on nitrogenase activity in cyanobacterial-lichen soil crusts

USGS Publications Warehouse

Belnap, Jayne

1996-01-01

CyanobacteriaMichen soil crusts can be a dominant source of nitrogen for cold-desert ecosystems. Effects of surface disturbance from footprints, bike and vehicle tracks on the nitrogenase activity in these crusts was investigated. Surface disturbances reduced nitrogenase activity by 30-100%. Crusts dominated by the cyanobacterium Microcoleus vaginatus on sandy soils were the most susceptible to disruption; crusts on gypsiferous soils were the least susceptible. Crusts where the soil lichen Collema tenax was present showed less immediate effects; however, nitrogenase activity still declined over time. Levels of nitrogenase activity reduction were affected by the degree of soil disruption and whether sites were dominated by cyanobacteria with or without heterocysts. Consequently, anthropogenic surface disturbances may have serious implications for nitrogen budgets in these ecosystems.

Decomposition Dynamics and Changes in Chemical Composition of Wheat Straw Residue under Anaerobic and Aerobic Conditions

PubMed Central

Gao, Hongjian; Chen, Xi; Wei, Junling; Zhang, Yajie; Zhang, Ligan; Chang, Jiang; Thompson, Michael L.

2016-01-01

Soil aeration is a crucial factor that regulates crop residue decomposition, and the chemical composition of decomposing crop residues may change the forms and availability of soil nutrients, such as N and P. However, to date, differences in the chemical composition of crop straw residues after incorporation into soil and during its decomposition under anaerobic vs. aerobic conditions have not been well documented. The objective of the present study was to assess changes in the C-containing functional groups of wheat straw residue during its decomposition in anaerobic and aerobic environments. A 12-month incubation experiment was carried out to investigate the temporal variations of mass, carbon, and nitrogen loss, as well as changes in the chemical composition of wheat (Triticum aestivum L) straw residues under anaerobic and aerobic conditions by measuring C-containing functional groups using solid state nuclear magnetic resonance (NMR) spectroscopy. The residual mass, carbon content, and nitrogen content of the straw residue sharply declined during the initial 3 months, and then slowly decreased during the last incubation period from 3 to 12 months. The decomposition rate constant (k) for mass loss under aerobic conditions (0.022 d-1) was higher than that under anaerobic conditions (0.014 d-1). The residual mass percentage of cellulose and hemicellulose in the wheat straw gradually declined, whereas that of lignin gradually increased during the entire 12-month incubation period. The NMR spectra of C-containing functional groups in the decomposing straw under both aerobic and anaerobic conditions were similar at the beginning of the incubation as well as at 1 month, 6 months, and 12 months. The main alterations in C-containing functional groups during the decomposition of wheat straw were a decrease in the relative abundances of O-alkyl C and an increase in the relative abundances of alkyl C, aromatic C and COO/N-C = O functional groups. The NMR signals of alkyl C

Fundamental Properties of Soils for Complex Dynamic Loadings: Dynamic Constitutive Modeling of Sandy Soils.

DTIC Science & Technology

1983-04-01

1.0 INTRODUCTION AND SCOPE 1 2.0 PROGRESS SUMMARY 3 2.1 Soil Element Model Development 3 2.2 U.S. Any Engineer Waterways Experiment Station (WES...LABORATORY BEHAVIOR OF SAND 8 3.1 Introduction 8 3.2 Material Description 8 3.3 Laboratory Tests Performed 9 3.4 Laboratory Test Results 14 4.0 MODELING THE... INTRODUCTION AND SCOPE The subject of this annual report is constitutive modeling of cohesionless soil, for both laboratory standard static test conditions

Effect of biochar or activated carbon amendment on the volatilisation and biodegradation of organic soil pollutants

NASA Astrophysics Data System (ADS)

Werner, David; Meynet, Paola; Bushnaf, Khaled

2013-04-01

Biochar or activated carbon added to contaminated soil may temporarily reduce the volatilisation of organic pollutants by enhanced sorption. The long-term effect of sorbent amendments on the fate of volatile petroleum hydrocarbon mixtures (VPHs) will depend on the responses of the soil bacterial community members, especially those which may utilize VPHs as carbon substrates. We investigated the volatilisation and biodegradation of VPHs emanating from NAPL sources and migrating through one meter long columns containing unsaturated sandy soil with and without 2% biochar or activated carbon amendment. After 420 days, VPH volatilisation from AC amended soil was less than 10 percent of the cumulative VPH volatilisation flux from unamended soil. The cumulative CO2 volatilisation flux increased more slowly in AC amended soil, but was comparable to the untreated soil after 420 days. This indicated that the pollution attenuation over a 1 meter distance was improved by the AC amendment. Biochar was a weaker VPH sorbent than AC and had a lesser effect on the cumulative VPH and CO2 fluxes. We also investgated the predominant bacterial community responses in sandy soil to biochar and/or VPH addition with a factorially designed batch study, and by analyzing preserved soil samples. Biochar addition alone had only weak effects on soil bacterial communities, while VPH addition was a strong community structure shaping factor. The bacterial community effects of biochar-enhanced VPH sorption were moderated by the limited biomass carrying capacity of the sandy soil investigated which contained only low amounts of inorganic nitrogen. Several Pseudomonas spp., including Pseudomonas putida strains, became dominant in VPH polluted soil with and without biochar. The ability of these versatile VPH degraders to effectively regulate their metabolic pathways according to substrate availabilities may additionally have moderated bacterial community structure responses to the presence of biochar

Characteristics of the soil-like substrates produced with a novel technique combining aerobic fermentation and earthworm treatment

NASA Astrophysics Data System (ADS)

Kang, Wenli; He, Wenting; Li, Leyuan; Liu, Hong

2012-12-01

The soil-like substrate (SLS) technique is key for improving the closure of bioregenerative life support system (BLSS) by recycling the inedible biomass of higher plants. In this study, a novel SLS technique (NSLST) was proposed: aerobic fermentations at 35 °C for 1 day, then 60 °C for 6 days, finally 30 °C for 3 days, followed by earthworm treatment for 70 days. Comparing with the original SLS technique (OSLST), its process cycle was 13 days shorter, and the dry weight loss rate (81.1%) was improved by 24.77%. The cellulose and lignin degradation rates were 96.6% and 94.6%. The concentrations of available N, P and K in mature SLS were respectively 776.1 mg/L, 348.0 mg/L and 7943.0 mg/L. Low CH4 and NH3 production was observed, but no accumulation. According to the seed germination test, the SLSs were feasible for plant growth. This investigation will provide a preliminary foundation for BLSS design.

Changes in labile soil organic matter fractions following land use change from monocropping to poplar-based agroforestry systems in a semiarid region of Northeast China.

PubMed

Mao, Rong; Zeng, De-Hui; Li, Lu-Jun; Hu, Ya-Lin

2012-11-01

Labile fractions of soil organic matter (SOM) respond rapidly to land management practices and can be used as a sensitive indicator of changes in SOM. However, there is little information about the effect of agroforestry practices on labile SOM fractions in semiarid regions of China. In order to test the effects of land use change from monocropping to agroforestry systems on labile SOM fractions, we investigated soil microbial biomass C (MBC) and N, particulate organic matter C (POMC) and N (POMN), as well as total organic C (TOC) and total N (TN) in the 0- to 15-cm and the 15- to 30-cm layers in 4-year-old poplar-based agroforestry systems and adjoining monocropping systems with two different soil textures (sandy loam and sandy clay loam) in a semiarid region of Northeast China. Our results showed that poplar-based agroforestry practices affected soil MBC, POMC, and POMN, albeit there was no significant difference in TOC and TN. Agroforestry practices increased MBC, POMC, and POMN in sandy clay loam soils. However, in sandy loam soils, agroforestry practices only increased MBC and even decreased POMC and POMN at the 0- to 15-cm layer. Our results suggest that labile SOM fractions respond sensitively to poplar-based agroforestry practices and can provide early information about the changes in SOM in semiarid regions of Northeast China and highlight that the effects of agroforestry practices on labile SOM fractions vary with soil texture.

Adsorption and degradation of five selected antibiotics in agricultural soil.

PubMed

Pan, Min; Chu, L M

2016-03-01

Large quantities of antibiotics are being added to agricultural fields worldwide through the application of wastewater, manures and biosolids, resulting in antibiotic contamination and elevated environmental risks in terrestrial environments. Most studies on the environmental fate of antibiotics focus on aquatic environments or wastewater treatment plants. Little is known about the behavior of antibiotics at environmentally relevant concentrations in agricultural soil. In this study we evaluated the adsorption and degradation of five different antibiotics (tetracycline, sulfamethazine, norfloxacin, erythromycin, and chloramphenicol) in sterilized and non-sterilized agricultural soils under aerobic and anaerobic conditions. Adsorption was highest for tetracycline (Kd, 1093 L/kg), while that for sulfamethazine was negligible (Kd, 1.365 L/kg). All five antibiotics were susceptible to microbial degradation under aerobic conditions, with half-lives ranging from 2.9 to 43.3 d in non-sterilized soil and 40.8 to 86.6 d in sterilized soil. Degradation occurred at a higher rate under aerobic conditions but was relatively persistent under anaerobic conditions. For all the antibiotics, a higher initial concentration was found to slow down degradation and prolong persistence in soil. The degradation behavior of the antibiotics varied in relation to their physicochemical properties as well as the microbial activities and aeration of the recipient soil. The poor adsorption and relative persistence of sulfamethazine under both aerobic and anaerobic conditions suggest that it may pose a higher risk to groundwater quality. An equation was proposed to predict the fate of antibiotics in soil under different field conditions, and assess their risks to the environment. Copyright © 2015 Elsevier B.V. All rights reserved.

A Case Study of Petroleum Degradation in Different Soil Textural Classes.

PubMed

Kogbara, Reginald B; Ayotamuno, Josiah M; Worlu, Daniel C; Fubara-Manuel, Isoteim

2016-01-01

Patents have been granted for a number of techniques for petroleum biodegradation including use of micro-organisms for degradation of hydrocarbon-based substances and for hydrocarbon degradation in oil reservoirs, but there is a dearth of information on hydrocarbon degradation in different soil textures. Hence, this work investigated the effects of different soil textures on degradation of petroleum hydrocarbons during a six-week period. Five soil textural classes commonly found in Port Harcourt metropolis, Nigeria, namely sand, loamy sand, sandy loam, silty clay and clay, were employed. The soils were contaminated with the same amount of crude oil and then remediated by biostimulation. Selected soil properties were monitored over time. Bacterial numbers declined significantly in the fine soil textures after petroleum contamination, but were either unaffected or increased significantly in the coarser soil textures. Hydrocarbon losses ranged from 42% - 99%; the sandy loam had the highest, while the clay soil had the least total hydrocarbon content (THC) reduction. The total heterotrophic bacterial (THB) counts generally corroborated the THC results. Fold increase in bacterial numbers due to remediation treatment decreased with increasing clay content. The results suggest that higher sand than clay content of soil favours faster hydrocarbon degradation. Hydrocarbon degradation efficiency increased with silt content among soil groupings such as fine and coarse soils but not necessarily with increasing silt content of soil. Thus, there seems to be cut-off sand and clay contents in soil at which the effect of the silt content becomes significant.