Soil properties affect the toxicities of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to the enchytraeid worm Enchytraeus crypticus.

PubMed

Kuperman, Roman G; Checkai, Ronald T; Simini, Michael; Phillips, Carlton T; Kolakowski, Jan E; Lanno, Roman

2013-11-01

The authors investigated individual toxicities of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to the potworm Enchytraeus crypticus using the enchytraeid reproduction test. Studies were designed to generate ecotoxicological benchmarks that can be used for developing ecological soil-screening levels for ecological risk assessments of contaminated soils and to identify and characterize the predominant soil physicochemical parameters that can affect the toxicities of TNT and RDX to E. crypticus. Soils, which had a wide range of physicochemical parameters, included Teller sandy loam, Sassafras sandy loam, Richfield clay loam, Kirkland clay loam, and Webster clay loam. Analyses of quantitative relationships between the toxicological benchmarks for TNT and soil property measurements identified soil organic matter content as the dominant property mitigating TNT toxicity for juvenile production by E. crypticus in freshly amended soil. Both the clay and organic matter contents of the soil modulated reproduction toxicity of TNT that was weathered and aged in soil for 3 mo. Toxicity of RDX for E. crypticus was greater in the coarse-textured sandy loam soils compared with the fine-textured clay loam soils. The present studies revealed alterations in toxicity to E. crypticus after weathering and aging TNT in soil, and these alterations were soil- and endpoint-specific. © 2013 SETAC.

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]).

Electrochemical techniques implementation for corrosion rate measurement in function of humidity level in grounding systems (copper and stainless steel) in soil samples from Tunja (Colombia)

NASA Astrophysics Data System (ADS)

Salas, Y.; Guerrero, L.; Blanco, J.; Jimenez, C.; Vera-Monroy, S. P.; Mejía-Camacho, A.

2017-12-01

In this work, DC electrochemical techniques were used to determine the corrosion rate of copper and stainless-steel electrodes used in grounding, varying the level of humidity, in sandy loam and clay loam soils. The maximum corrosion potentials were: for copper -211 and -236mV and for stainless steel of -252 and -281mV, in sandy loam and clay loam respectively, showing that in sandy loam the values are higher, about 30mV. The mechanism by which steel controls corrosion is by diffusion, whereas in copper it is carried out by transfer of mass and charge, which affects the rate of corrosion, which in copper reached a maximum value of 5mm/yr and in Steel 0.8mm/yr, determined by Tafel approximations. The behaviour of the corrosion rate was mathematically adjusted to an asymptotic model that faithfully explains the C.R. as a function of humidity, however, it is necessary to define the relation between the factor □ established in the model and the precise characteristics of the soil, such as the permeability or quantity of ions present.

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...

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.

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.

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.

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 largest and accumulated the most total As, while under field conditions, control and compost-treated ferns accumulated the most total As. Under greenhouse conditions, leaching appeared to account for most As removed from sandy loam soil. Results from a similar greenhouse study now underway in clayey soil will be discussed.

Effects of slaking and mechanical breakdown on disaggregation and splash erosion

USDA-ARS?s Scientific Manuscript database

The contributions of different aggregate breakdown mechanisms to splash erosion are still obscure. This study was designed to investigate the effects of different soil disaggregation mechanisms on splash erosion. Loam clay soil, clay loam soil, and sandy loam soil were used in this study. Soil aggre...

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

Electrical Imaging of Infiltration in Agricultural Soils on Long Island, New York

NASA Astrophysics Data System (ADS)

Lampousis, A.; Kenyon, P. M.; Sanwald, K.; Steiner, N.

2007-12-01

High resolution electrical resistivity imaging of vadose zone infiltration experiments was conducted on agricultural soils by the City College and Graduate Center of CUNY, in cooperation with Cornell University's Agricultural Stewardship Program and Long Island Horticultural Research and Extension Center (LIHREC) in Riverhead, New York. Measurements were made in active vineyards with a commercial resistivity imaging system, using a half- meter electrode spacing. Soils considered were Riverhead sandy loam (RdA), Haven loam (HaA), and Bridgehampton silty loam (BgA). The Riverhead and Haven soils are the most common types found on eastern Long Island. The Bridgehampton is considered the most fertile. Soil samples and measurements of soil compaction were collected at the same time as the geophysical measurements. In addition, remote sensing data were obtained for the three sites and processed to produce normalized difference vegetation index (NDVI) data to evaluate potential correlations between vegetation vigor, soil texture and water migration patterns. Applications of this study include continuous water content monitoring in high value cash crops (precision agriculture). Changes in electrical resistivity during infiltration are clearly visible at all three locations. Preliminary analysis of the results shows correlations of baseline resistivity with particle size distributions and correlations between changes in resistivity during infiltration and soil compaction data. Time-lapse electrical images of the three sites will also be compared with published properties for these soils, including particle size distribution, saturated hydraulic conductivity, available water capacity, and surface texture.

Analyzing the Sand-fixing Effect of Feldspathic Sandstone from the Texture Characteristics

NASA Astrophysics Data System (ADS)

Zhang, lu; Ban, Jichang

2018-01-01

The purpose of this research was aimed to study the sand fixing effect of feldspathic sandstone in Mu Us Sandy Land, to provide a scienticic basis for desertification control, soil and water conservation and development of farming there. Methods of mixing feldspathic sandstone and aeolian sandy soil according to 1: 0, 1: 1, 1: 2, 1: 5, and 0: 1 mass ratioes, the graded composition and characteristics were studied with laser particle size analyzer. The result showed that these features of sand-based, loosely structured, easy to wind erosion of aeolian sandy soil were changed before feldspathic sandstone and aeolian sandy soil compounding. The <0.05 mm particle mass increased with feldspathic sandstone mass increasing. The texture presented this kind of change from sand to sandy loam to loam to silt loam. The small particle size distribution, good homogeneity and other features of aeolian sandy soil were improved to a certain degree, and the particle size distribution became broad before feldspathic sandstone and aeolian sandy soil compounding. The particle grading was continuous, and the grading characteristic was good when m(F): m(S) was 1: 5(Cu was 54.71 and Cc was 2.54) or when m(F): m(S) was 1: 2(Cu was 76.21, Cc was 1.12). The conclusion is that feldspathic sandstone has sand-fixing effect in texture characteristics, which heightens with feldspathic sandstone mass increasing, and when the mass ratio of feldspathic sandstone: aeolian sandy soil is 1: 2 or 1: 5 which compound better.

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

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.

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...

Soil Texture and Cultivar Effects on Rice (Oryza sativa, L.) Grain Yield, Yield Components and Water Productivity in Three Water Regimes.

PubMed

Dou, Fugen; Soriano, Junel; Tabien, Rodante E; Chen, Kun

2016-01-01

The objective of this study was to determine the effects of water regime/soil condition (continuous flooding, saturated, and aerobic), cultivar ('Cocodrie' and 'Rondo'), and soil texture (clay and sandy loam) on rice grain yield, yield components and water productivity using a greenhouse trial. Rice grain yield was significantly affected by soil texture and the interaction between water regime and cultivar. Significantly higher yield was obtained in continuous flooding than in aerobic and saturated soil conditions but the latter treatments were comparable to each other. For Rondo, its grain yield has decreased with soil water regimes in the order of continuous flooding, saturated and aerobic treatments. The rice grain yield in clay soil was 46% higher than in sandy loam soil averaged across cultivar and water regime. Compared to aerobic condition, saturated and continuous flooding treatments had greater panicle numbers. In addition, panicle number in clay soil was 25% higher than in sandy loam soil. The spikelet number of Cocodrie was 29% greater than that of Rondo, indicating that rice cultivar had greater effect on spikelet number than soil type and water management. Water productivity was significantly affected by the interaction of water regime and cultivar. Compared to sandy loam soil, clay soil was 25% higher in water productivity. Our results indicated that cultivar selection and soil texture are important factors in deciding what water management option to practice.

Dominant Douglas-fir respond to fertilizing and thinning in southwest Oregon

Treesearch

Richard E. Miller; Richard L. Williamson

1974-01-01

In 30-year-old, Site IV Douglas-fir in southwest Oregon, fertilizing increased average 4-year basal area growth of dominant trees by 57 and 28 percent on clay loam and sandy loam soils, respectively. Fertilizing with thinning increased growth by 94 and 132 percent over untreated growth. Thinning on clay loam soil increased growth by 53 percent. Treatment did not affect...

Interaction of the Bored Sand and Gravel Drain Pile with the Surrounding Compacted Loam Soil and Foundation Raft Taking into Account Rheological Properties of the Loam Soil and Non-Linear Properties of the Drain Pile

NASA Astrophysics Data System (ADS)

Ter-Martirosyan, Z. G.; Ter-Martirosyan, A. Z.; Anzhelo, G. O.; Buslov, A. S.

2018-01-01

The task of the interaction of the sand and gravel drain pile with the surrounding loam soil after its preliminary deep compaction and formation of the composite ground cylinder from the drain pile and surrounding compacted loam soil (cells) is considered in the article. It is seen that the subsidence and carrying capacity of such cell considerably depends on physical and mechanical properties of the compacted drain piles and surrounding loam soil as well as their diameter and intercellular distance. The strain-stress state of the cell is considered not taking into account its component elements, but taking into account linear and elastic-plastic properties of the drain pile and creep flow of the surrounding loam soil. It is stated that depending on these properties the distribution and redistribution of the load on a cell takes place from the foundation raft between the drain pile and surrounding soil. Based on the results of task solving the formulas and charts are given demonstrating the ratio of the load between the drain pile and surrounding loam soil in time.

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.

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.

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.

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 conditioning effect.

PHYSICOCHEMICAL PROPERTIES AS PREDICTORS OF ORGANIC CHEMICAL EFFECTS ON SOIL MICROBIAL RESPIRATION

EPA Science Inventory

Structure-activity analysis was used to evaluate the effects of 19 hazardous organic chemicals on microbial respiration in two slightly acidic soils (a Captina silt loam from Roane County Tennessee, and a McLaurin sandy loam from Stone County, Mississippi), both low in organic ca...

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.

Site-specific early performance and nutrition of two Salix species in SRIC in southern Quebec (Canada)

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

Labrecque, M.; Teodorescu, T.I.; Daigle, S.

1996-12-31

Salix discolor WU and Salix viminalis L. were planted under short-rotation intensive culture (SRIC) in three unirrigated and unfertilized abandoned farmland sites (S1, S2, S3) showing different soil textures: sandy loam, clay silt and clay loam. The aims of the experiment were to: (i) investigate first year response to site nutrient condition and (ii) diagnose factors limiting performance. Over the first season, stem biomass productivity was superior on the sandy site (S1) for S. discolor and did not vary between species on clay sites (S2, S3). The inferior performance of plants on clay sites was related to difficulty implanting unrootedmore » cuttings in compacted soil during an exceptionally dry period (May and June). The change in nutrient status was unapparent solely from comparison of critical levels or optimum ratios because leaf nutrient concentration was less affected by site. Diagnostic techniques based on vector analysis of leaf nutrient concentration, content, and dry mass allowed simultaneous comparison of the nutrient status of two species planted on three sites. The relative deficiency of all nutrients, based on vector magnitude and direction, on the two other clay sites (S2, S3) supports the hypothesis that specific edaphic conditions and dryness induced nutrient disorders in willows. Successful establishment of willows in SRIC depends strongly on the characteristics of the plantation site and on precipitation during the establishment phase in the first year of growth.« less

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.

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.

Influence of wood-derived biochar on the compactibility and strength of silt loam soil

NASA Astrophysics Data System (ADS)

Ahmed, Ahmed; Gariepy, Yvan; Raghavan, Vijaya

2017-04-01

Biochar is proven to enhance soil fertility and increase crop productivity. Given that the influence of biochar on soil compaction remains unclear, selected physico-mechanical properties of soil amended with wood-derived biochar were assessed. For unamended silt loam, the bulk density, maximum bulk density, optimum moisture content, plastic limit, liquid limit, and plasticity index were 1.05 Mg m-3, 1.69 Mg m-3, 16.55, 17.1, 29.3, and 12.2%, respectively. The penetration resistance and shear strength of the unamended silt loam compacted in the standard compaction Proctor mold and at its optimum moisture content were 1800 kPa and 850 kPa, respectively. Results from amending the silt loam with 10% particle size ranges (0.5-212 μm) led to relative decreases of 18.1, 17.75, 66.66, and 97.4% in bulk density, maximum bulk density, penetration resistance, and shear strength, respectively; a 26.8% relative increase in optimum moisture content; along with absolute increases in plastic limit, liquid limit, and plasticity index of 5.3, 13.7, and 8.4%, respectively. While the biochar-amended silt loam soil was more susceptible to compaction, however, soil mechanical impedance enhanced.

Dissipation and leaching of pyroxasulfone and s-metolachlor

USDA-ARS?s Scientific Manuscript database

Pyroxasulfone dissipation and mobility in the soil was evaluated and compared to S-metolachlor in 2009 and 2010 at two field sites in northern Colorado, on a Nunn fine clay loam, and Olney fine sandy loam soil. Pyroxasulfone dissipation half-life (DT50) values varied from 47 to 134 d, and those of S...

Field performance of three real-time moisture sensors in sandy loam and clay loam soils

USDA-ARS?s Scientific Manuscript database

The study was conducted to evaluate HydraProbe (HyP), Campbell Time Domain Reflectometry (TDR) and Watermarks (WM) moisture sensors for their ability to estimate water content based on calibrated neutron probe measurements. The three sensors were in-situ tested under natural weather conditions over ...

Soil and groundwater attenuation factors for nitrogen from septic systems in the Chesapeake Bay TMDL

NASA Astrophysics Data System (ADS)

Radcliffe, D. E.; Geza, M.; O'Drisoll, M.; Humphrey, C., Jr.

2015-12-01

An expert panel was tasked with estimating the percent of the nitrogen (N) load from septic systems that was lost in the flow path from a typical home to third-order streams as part of the Chesapeake Bay Total Maximum Daily Load (TMDL). These losses were referred to as attenuation factors. We developed values for the soil (unsaturated) zone and for the Piedmont and Coastal Plain groundwater zones. For the soil zone, we used the Soil Treatment Unit MODel (STUMOD) to estimate loses due to denitrification for all 12 soil textural classes and then averaged the results over three textural groups. Assuming hydraulic loading at the design rate and a conventional system, the attenuation factors were 16% for sand, loamy sand, sandy loam, and loam soils; 34% for silt loam, clay loam, sandy clay loam, silty clay loam, and silt soils; and 54% for sandy clay, silty clay, and clay soils. Attenuation factors increased in the more clayey soils due to wetter conditions and more losses due to denitrification. Attenuation factors were also developed for reduced hydraulic loading rates and for systems using advanced N pre-treatment. For the Piedmont groundwater zone, we used data from a recent study in Georgia of small suburban streams with high-density septic systems. Stream base-flow load was estimated using simultaneous measurements of total N concentration and discharge and compared to the estimated groundwater input load, resulting in an attenuation factor of 81%. For the Coastal Plain groundwater zone, literature values of groundwater N concentrations within septic system plumes in Virginia, North Carolina, and Florida were used to estimate an attenuation factor of approximately 60% at 100m downgradient from the drainfield. These attenuation factors will be used to estimate the contribution of N to the Chesapeake Bay in the Phase 6 TMDL models.

An Experimental Study of the Effects of Litter and Duff Consumption and Ash Formation on Post-Fire Runoff.

NASA Astrophysics Data System (ADS)

Woods, S. W.; Balfour, V.

2007-12-01

Consumption of the litter and duff layers in forest wildfires can lead to substantial increases in the frequency and magnitude of overland flow. These increases result from the loss of storage in the organic surface layer, reduced surface roughness, and from sealing of the exposed mineral soil surface. The presence of an ash layer may accentuate surface sealing by providing an additional source of fine material, or it may reduce runoff by storing rainfall and by protecting the soil surface from raindrop impacts. We used simulated rainfall experiments to assess the effects of litter and duff consumption and the presence of ash layers of varying thickness on post fire runoff at two forested sites in western Montana, one with sandy loam soils formed out of granodiorite and the other with gravelly silt loam soils formed out of argillite. At each site we measured the runoff from simulated rainfall in replicated 0.5 m2 plots before and after application of the following treatments: 1) burning with a fuel load of 90 Mg ha-1, 2) manual removal of the litter and duff layers, 3) addition of 0.5, 2.5 and 5 cm of ash to plots from which the litter and duff had previously been removed, and 4) addition of the same depths of ash to burned plots at the sandy loam site. In the burned plots the surface litter and duff layers were completely consumed and a <1cm layer of black and gray ash and char was formed, indicating a moderate severity burn. The mean soil temperature in the upper 1 cm of the mineral soil was 70° C, and there was no detectable increase in water repellency. The mean final infiltration capacity of the burned sandy loam plots was 35 mm hr-1 compared to a pre-fire mean of 87 mm hr-1, while in the gravelly silt loam plots the pre- and post burn infiltration capacities (27 and 31 mm hr- 1) were not significantly different. Manual removal of the litter and duff layers reduced the mean final infiltration capacity in the sandy loam plots from 64 mm hr-1 to 40 mm hr-1 and in the gravelly silt loam plots from 23 mm hr-1 to 16 mm hr-1. We attribute decreases in infiltration due to the burning and duff removal treatments primarily to surface sealing. In the sandy loam plots, burning may have had a greater effect on infiltration than duff removal because the thin ash layer in the burned plots provided an additional source of fine material. In the gravelly silt loam plots, macropores located around rock fragments helped to minimize sealing effects. The addition of 0.5 cm of ash to the burned granitic plots resulted in a 20 mm hr-1 decrease in the final infiltration rate, and this was also probably due to surface sealing. However, the overall effect of ash addition was to increase the cumulative infiltration in proportion to the ash thickness and to maintain a higher average infiltration rate, indicating that while thin (<1 cm) ash layers may promote sealing, thicker ash layers help to reduce the runoff rate by providing additional storage for rainfall and by protecting the soil surface from raindrop impacts.

Mucilage from seeds of chia (Salvia hispanica L.) used as soil conditioner; effects on the sorption-desorption of four herbicides in three different soils.

PubMed

Di Marsico, A; Scrano, L; Amato, M; Gàmiz, B; Real, M; Cox, L

2018-06-01

The objective of this work was to determine the effect of the mucilage extracted from Chia seeds (Salvia hispanica L.) as soil amendment on soil physical properties and on the sorption-desorption behaviour of four herbicides (MCPA, Diuron, Clomazone and Terbuthylazine) used in cereal crops. Three soils of different texture (sandy-loam, loam and clay-loam) were selected, and mercury intrusion porosimetry and surface area analysis were used to examine changes in the microstructural characteristics caused by the reactions that occur between the mucilage and soil particles. Laboratory studies were conducted to characterise the selected herbicides with regard their sorption on tested soils added or not with the mucilage. Mucilage amendment resulted in a reduction in soil porosity, basically due to a reduction in larger pores (radius>10μm) and an important increase in finer pores (radius<10μm) and in partcles' surface. A higher herbicide sorption in the amended soils was ascertained when compared to unamended soils. The sorption percentage of herbicides in soils treated with mucilage increased in the order; sandy-loam

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

Changes in microbial community structure following herbicide (glyphosate) additions to forest soils

Treesearch

Alice W. Ratcliff; Matt D. Busse; Carol J. Shestak

2006-01-01

Glyphosate applied at the recommended field rate to a clay loam and a sandy loam forest soil resulted in few changes in microbial community structure. Total and culturable bacteria, fungal hyphal length, bacterial:fungal biomass, carbon utilization profiles (BIOLOG), and bacterial and fungal phospholipid fatty acids (PLFA) were unaffected 1, 3, 7, or 30 days...

Soil compaction vulnerability at Organ Pipe Cactus National Monument, Arizona

USGS Publications Warehouse

Webb, Robert H.; Nussear, Kenneth E.; Carmichael, Shinji; Esque, Todd C.

2014-01-01

Compaction vulnerability of different types of soils by hikers and vehicles is poorly known, particularly for soils of arid and semiarid regions. Engineering analyses have long shown that poorly sorted soils (for example, sandy loams) compact to high densities, whereas well-sorted soils (for example, eolian sand) do not compact, and high gravel content may reduce compaction. Organ Pipe Cactus National Monument (ORPI) in southwestern Arizona, is affected greatly by illicit activities associated with the United States–Mexico border, and has many soils that resource managers consider to be highly vulnerable to compaction. Using geospatial soils data for ORPI, compaction vulnerability was estimated qualitatively based on the amount of gravel and the degree of sorting of sand and finer particles. To test this qualitative assessment, soil samples were collected from 48 sites across all soil map units, and undisturbed bulk densities were measured. A scoring system was used to create a vulnerability index for soils on the basis of particle-size sorting, soil properties derived from Proctor compaction analyses, and the field undisturbed bulk densities. The results of the laboratory analyses indicated that the qualitative assessments of soil compaction vulnerability underestimated the area of high vulnerability soils by 73 percent. The results showed that compaction vulnerability of desert soils, such as those at ORPI, can be quantified using laboratory tests and evaluated using geographic information system analyses, providing a management tool that managers potentially could use to inform decisions about activities that reduce this type of soil disruption in protected areas.

Comparison of planted loblolly, longleaf, and slash pine development through 10 growing seasons in central Louisiana--an argument for longleaf pine

Treesearch

James D. Haywood; Mary Anne S. Sayer; Shi-Jean Susana Sung

2015-01-01

Two studies were established in central Louisiana to compare development of planted loblolly (Pinus taeda L.), longleaf (P. palustris Mill.), and slash (P. elliottii Engelm.) pine. Study 1 was on a Beauregard silt loam, and Study 2 was on Ruston and McKamie fine sandy loams. After 10 growing seasons,...

Use of a size-resolved 1-D resuspension scheme to evaluate resuspended radioactive material associated with mineral dust particles from the ground surface.

PubMed

Ishizuka, Masahide; Mikami, Masao; Tanaka, Taichu Y; Igarashi, Yasuhito; Kita, Kazuyuki; Yamada, Yutaka; Yoshida, Naohiro; Toyoda, Sakae; Satou, Yukihiko; Kinase, Takeshi; Ninomiya, Kazuhiko; Shinohara, Atsushi

2017-01-01

A size-resolved, one-dimensional resuspension scheme for soil particles from the ground surface is proposed to evaluate the concentration of radioactivity in the atmosphere due to the secondary emission of radioactive material. The particle size distributions of radioactive particles at a sampling point were measured and compared with the results evaluated by the scheme using four different soil textures: sand, loamy sand, sandy loam, and silty loam. For sandy loam and silty loam, the results were in good agreement with the size-resolved atmospheric radioactivity concentrations observed at a school ground in Tsushima District, Namie Town, Fukushima, which was heavily contaminated after the Fukushima Dai-ichi Nuclear Power Plant accident in March 2011. Though various assumptions were incorporated into both the scheme and evaluation conditions, this study shows that the proposed scheme can be applied to evaluate secondary emissions caused by aeolian resuspension of radioactive materials associated with mineral dust particles from the ground surface. The results underscore the importance of taking soil texture into account when evaluating the concentrations of resuspended, size-resolved atmospheric radioactivity. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

Vertical movement of iron-cyanide complexes in soils of a former Manufactured Gas Plant site

NASA Astrophysics Data System (ADS)

Sut, Magdalena; Repmann, Frank; Raab, Thomas

2015-04-01

In Germany, soil and groundwater at more than a thousand sites are contaminated with iron-cyanide complexes. These contaminations originate from the gas purification process that was conducted in Manufactured Gas Plants (MGP). The phenomenon of iron-cyanide complexes 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. This study suggests vertical transport of a colloidal ferric ferrocyanide, in the excess of iron and circum-neutral pH conditions, as an alternative process that influences the retardation of the pollutant movement through the soil profile. Preliminary in situ investigations of the two boreholes implied 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). The acidic character of the wastes and the accumulation of the blue patches suggested the potential filter function of a sandy loam material due to colloidal transport of the ferric ferricyanide. Series of batch and column experiments, using sandy loam soil, revealed reduction of CN concentration due to mechanical filtration of precipitated solid iron-cyanide complexes and due to the formation of potassium manganese iron-cyanide (K2Mn[Fe(CN)6]).

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.

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.

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.

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...

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 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

Evaluation of soil manipulation to prepare engineered earthen waste covers for revegetation

DOE PAGES

Waugh, W. Joseph; Benson, Craig H.; Albright, William H.; ...

2015-10-21

Seven ripping treatments designed to improve soil physical conditions for revegetation were compared on a test pad simulating an earthen cover for a waste disposal cell. The field test was part of study of methods to convert compacted-soil waste covers into evapotranspiration covers. The test pad consisted of a compacted layer of fine-textured soil simulating a barrier protection layer overlain by a gravelly sand bedding layer and a cobble armor layer. Treatments included combinations of soil-ripping implements (conventional shank [CS], wing-tipped shank [WTS], and parabolic oscillating shank with wings [POS]), ripping depths, and number of passes. Dimensions, dry density, moisturemore » content, and particle size distribution of disturbance zones were determined in two trenches excavated across rip rows. The goal was to create a root-zone dry density between 1.2 and 1.6 Mg m-3 and a seedbed soil texture ranging from clay loam to sandy loam with low rock content. All treatments created V-shaped disturbance zones as measured on trench faces. Disturbance zone size was most influenced by ripping depth. Winged implements created larger disturbance zones. All treatments lifted fines into the bedding layer, moved gravel and cobble down into the fine-textured protection layer, and thereby disrupted the capillary barrier at the interface. Changes in dry density within disturbance zones were comparable for the CS and WTS treatments but were highly variable among POS treatments. Water content increased in the bedding layer and decreased in the protection layer after ripping. The POS at 1.2-m depth and two passes created the largest zone with a low dry density (1.24 Mg m-3) and the most favorable seedbed soil texture (gravely silt loam). Furthermore, ripping also created large soil aggregates and voids in the protection layer that may produce preferential flow paths and reduce water storage capacity.« less

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.

Pine Regeneration with Simultaneous Control of Kudzu

Treesearch

Jerry L. Michael

1986-01-01

Kudzu (Pueraria lobata (Willd.)Ohwi) growing on clay, clay loam, and sandy loam soils in cm and north Alabama was treated in a randomized design on each soil type with three replications using three application rates of Arsenal@ (imazapyr at 0.5, 1.0, and 2.0 lb se/a), a single rate of Tordone 101 [1.35 lb ae/a picloram plus 5 lb se/a 2,4-...

Interactions between soil texture and placement of dairy slurry application: I. Flow characteristics and leaching of nonreactive components.

PubMed

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

2011-01-01

Land application of manure can exacerbate nutrient and contaminant transfers to the aquatic environment. This study examined the effect of injecting a dairy cattle (Bostaurus L.) manure slurry on mobilization and leaching of dissolved, nonreactive slurry components across a range of agricultural soils. We compared leaching of slurry-applied bromide through intact soil columns (20 cm diam., 20 cm high) of differing textures following surface application or injection of slurry. The volumetric fraction of soil pores >30 microm ranged from 43% in a loamy sand to 28% in a sandy loam and 15% in a loam-textured soil. Smaller active flow volumes and higher proportions of preferential flow were observed with increasing soil clay content. Injection of slurry in the loam soil significantly enhanced diffusion of applied bromide into the large fraction of small pores compared with surface application. The resulting physical protection against leaching of bromide was reflected by 60.2% of the bromide tracer was recovered in the effluent after injection, compared with 80.6% recovery after surface application. No effect of slurry injection was observed in the loamy sand and sandy loam soils. Our findings point to soil texture as an important factor influencing leaching of dissolved, nonreactive slurry components in soils amended with manure slurry.

Soil salinity and matric potential interaction on water use, water use efficiency and yield response factor of bean and wheat.

PubMed

Khataar, Mahnaz; Mohhamadi, Mohammad Hossien; Shabani, Farzin

2018-02-08

We studied the effects of soil matric potential and salinity on the water use (WU), water use efficiency (WUE) and yield response factor (Ky), for wheat (Triticum aestivum cv. Mahdavi) and bean (Phaseoulus vulgaris cv. COS16) in sandy loam and clay loam soils under greenhouse conditions. Results showed that aeration porosity is the predominant factor controlling WU, WUE, Ky and shoot biomass (Bs) at high soil water potentials. As matric potential was decreased, soil aeration improved, with Bs, WU and Ky reaching maximum value at -6 to -10 kPa, under all salinities. Wheat WUE remained almost unchanged by reduction of matric potential under low salinities (EC ≤ 8 dSm -1 ), but increased under higher salinities (EC ≥ 8 dSm -1 ), as did bean WUE at all salinities, as matric potential decreased to -33 kPa. Wheat WUE exceeds that of bean in both sandy loam and clay loam soils. WUE of both plants increased with higher shoot/root ratio and a high correlation coefficient exists between them. Results showed that salinity decreases all parameters, particularly at high potentials (h = -2 kPa), and amplifies the effects of waterlogging. Further, we observed a strong relationship between transpiration (T) and root respiration (Rr) for all experiments.

Willow water uptake and shoot extension growth in response to nutrient and moisture on a clay landfill cap soil.

PubMed

Martin, Peter J; Stephens, William

2008-09-01

Extension growth of willow (Salix viminalis L.) and changes in soil water were measured in lysimeters containing clay and sandy loam soils with different amendment and watering treatments. No water uptake was found below 0.3m in the nutritionally poor unamended clay; amendment with organic matter to 0.4m depth resulted in water extraction down to 0.5m depth whereas in the sandy loam, there was greater extraction from all depths down to 0.6m. With water stress, wilting of plants occurred when the volumetric soil water content at 0.1m was about 31% in the clay and 22% in the sandy loam. Compared with shoots on plants in the amended clay, those in the unamended treatment showed reduced extension growth, little increase in stem basal area (SBA) and a small shoot leaf area, resulting from a reduced number of leaves shoot(-1) and a small average area leaf(-1). Water stress also reduced shoot extension growth, SBA gain and the leaf area on extension growth. Shoot growth rates were significantly correlated with air temperature and base temperatures between 2.0 and 7.6 degrees C were indicated for the different treatments. These studies have helped to explain some of the large treatment effects described previously on biomass production and plant leaf area.

Spatial variation in the degradation rate of the pesticides isoproturon, azoxystrobin and diflufenican in soil and its relationship with chemical and microbial properties.

PubMed

Bending, Gary D; Lincoln, Suzanne D; Edmondson, Rodney N

2006-01-01

The extent of within field variability in the degradation rate of the pesticides isoproturon, azoxystrobin and diflufenican, and the role of intrinsic soil factors and technical errors in contributing to the variability, was investigated in sites on sandy-loam and clay-loam. At each site, 40 topsoil samples were taken from a 160 x 60 m area, and pesticides applied in the laboratory. Time to 25% dissipation (DT25) ranged between 13 and 61 weeks for diflufenican, 5.6 and 17.2 weeks for azoxystrobin, and 0.3 and 12.5 weeks for isoproturon. Variability in DT25 was higher in the sandy-loam in which there was also greatest variability in soil chemical and microbial properties. Technical error associated with pesticide extraction, analysis and lack of model fit during derivation of DT25 accounted for between 5.3 and 25.8% of the variability for isoproturon and azoxystrobin, but could account for almost all the variability for diflufenican. Azoxystrobin DT25, sorption and pH were significantly correlated.

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.

Spatial Dependence of Physical Attributes and Mechanical Properties of Ultisol in a Sugarcane Field.

PubMed

Tavares, Uilka Elisa; Rolim, Mário Monteiro; de Oliveira, Veronildo Souza; Pedrosa, Elvira Maria Regis; Siqueira, Glécio Machado; Magalhães, Adriana Guedes

2015-01-01

This study investigates the effect of conventional tillage and application of the monoculture of sugar cane on soil health. Variables like density, moisture, texture, consistency limits, and preconsolidation stress were taken as indicators of soil quality. The measurements were made at a 120 × 120 m field cropped with sugar cane under conventional tillage. The objective of this work was to characterize the soil and to study the spatial dependence of the physical and mechanical attributes. Then, undisturbed soil samples were collected to measure bulk density, moisture content and preconsolidation stress and disturbed soil samples for classification of soil texture, and consistency limits. The soil texture indicated that soil can be characterized as sandy clay soil and a sandy clay loam soil, and the consistency limits indicated that the soil presents an inorganic low plasticity clay. The preconsolidation tests tillage in soil moisture content around 19% should be avoided or should be chosen a management of soil with lighter vehicles in this moisture content, to avoid risk of compaction. Using geostatistical techniques mapping was possible to identify areas of greatest conservation soil and greater disturbance of the ground.

Spatial Dependence of Physical Attributes and Mechanical Properties of Ultisol in a Sugarcane Field

PubMed Central

Tavares, Uilka Elisa; Monteiro Rolim, Mário; Souza de Oliveira, Veronildo; Maria Regis Pedrosa, Elvira; Siqueira, Glécio Machado; Guedes Magalhães, Adriana

2015-01-01

This study investigates the effect of conventional tillage and application of the monoculture of sugar cane on soil health. Variables like density, moisture, texture, consistency limits, and preconsolidation stress were taken as indicators of soil quality. The measurements were made at a 120 × 120 m field cropped with sugar cane under conventional tillage. The objective of this work was to characterize the soil and to study the spatial dependence of the physical and mechanical attributes. Then, undisturbed soil samples were collected to measure bulk density, moisture content and preconsolidation stress and disturbed soil samples for classification of soil texture, and consistency limits. The soil texture indicated that soil can be characterized as sandy clay soil and a sandy clay loam soil, and the consistency limits indicated that the soil presents an inorganic low plasticity clay. The preconsolidation tests tillage in soil moisture content around 19% should be avoided or should be chosen a management of soil with lighter vehicles in this moisture content, to avoid risk of compaction. Using geostatistical techniques mapping was possible to identify areas of greatest conservation soil and greater disturbance of the ground. PMID:26167528

Electrical resistivity imaging study of near-surface infiltration

NASA Astrophysics Data System (ADS)

Lampousis, Angelos

High resolution electrical resistivity images (ERI method) were obtained during vadose zone infiltration experiments on agricultural soils in cooperation with Cornell University's Agricultural Stewardship Program, Cooperative Extension of Suffolk County, Extension Education Center, Riverhead, New York [ as well as Cornell University's Long Island Horticultural Research & Extension Center (LIHREC) in Riverhead, New York]. One natural soil was also studied. Infiltration was monitored by means of image analysis of two-dimensional array resistivity generated by a Syscal Kid Switch resistivity system (Griffiths et al., 1990). The data was inverted with the computer program RES2DINV (Loke, 2004). The agricultural soils considered were Riverhead sandy loam (RdA), Haven loam (HaA), and Bridgehampton silt loam (BgA). The natural site was located in the Catskill Mountains of New York State. The soils there are classified as Schoharie silty clay loam. The electrical images of the three sites were compared against established soil properties, including particle size distribution, available water capacity, and soluble salts (from the literature), as well as against site-specific soil samples and penetrometer data, which were collected along with the geophysical measurements. This research evaluates the potential of acquiring high resolution, non-destructive measurements of infiltration in the uppermost 1.5 meter of the vadose zone. The results demonstrate that resistivity differences can detect infiltration in soils typical of the north-eastern United States. Temporal and spatial variations of soil water content in the upper 1.5 meters (relevant to agriculture) of the subsurface can be monitored successfully and non-destructively with ERI. The sensitivity of the method is higher in subsurface environments that demonstrate high overall apparent resistivity values (e.g. high sand content). Under conditions of increased soil heterogeneity, instead of the formation of a continuous water plume as occurred in the homogeneous agricultural soils, the location of the infiltrated water seems to be highly influenced by the soil heterogeneity, and the water front is scattered into discontinuous layers and travels in additional directions. The geophysical results during infiltration correlate well with soil compaction data. It follows that the ERI method can be used as a proxy for soil compaction and water content variations in agricultural applications. In a natural environment, ERI successfully maps the tree root zone of mature trees. Applications include continuous water content monitoring in high value cash crops, such as viticulture (precision agriculture).

Dietary crude protein and tannin impact dairy manure chemistry and ammonia emissions from incubated soils.

PubMed

Powell, J M; Aguerre, M J; Wattiaux, M A

2011-01-01

Excess crude protein (CP) in dairy cow diets is excreted mostly as urea nitrogen (N), which increases ammonia (NH) emissions from dairy farms and heightens human health and environmental concerns. Feeding less CP and more tannin to dairy cows may enhance feed N use and milk production, abate NH emissions, and conserve the fertilizer N value of manure. Lab-scale ventilated chambers were used to evaluate the impacts of CP and tannin feeding on slurry chemistry, NH emissions, and soil inorganic N levels after slurry application to a sandy loam soil and a silt loam soil. Slurry from lactating Holstein dairy cows (Bos taurus) fed two levels of dietary CP (low CP [LCP], 155 g kg; high CP [HCP], 168 g kg) each fed at four levels of dietary tannin extract, a mixture from red quebracho (Schinopsis lorentzii) and chestnut (Castanea sativa) trees (0 tannin [0T]; low tannin [LT], 4.5 g kg; medium tannin [MT], 9.0 g kg; and high tannin [HT], 18.0 g kg) were applied to soil-containing lab-scale chambers, and NH emissions were measured 1, 3, 6, 12, 24, 36, and 48 h after slurry application. Emissions from the HCP slurry were 1.53 to 2.57 times greater ( < 0.05) than from the LCP slurry. At trial's end (48 h), concentrations of inorganic N in soils were greater ( < 0.05) in HCP slurry-amended soils than in LCP slurry-amended soils. Emissions from HT slurry were 28 to 49% lower ( < 0.05) than emissions from 0T slurry, yet these differences did not affect soil inorganic N levels. Emissions from the sandy loam soil were 1.07 to 1.15 times greater ( < 0.05) than from silt loam soil, a result that decreased soil inorganic N in the sandy loam compared with the silt loam soil. Larger-scale and longer-term field trails are needed to ascertain the effectiveness of feeding tannin extracts to dairy cows in abating NH loss from land-applied slurry and the impact of tannin-containing slurry on soil N cycles. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Vulnerability of tropical forest ecosystems and forest dependent communities to droughts.

PubMed

Vogt, D J; Vogt, K A; Gmur, S J; Scullion, J J; Suntana, A S; Daryanto, S; Sigurðardóttir, R

2016-01-01

Energy captured by and flowing through a forest ecosystem can be indexed by its total Net Primary Productivity (NPP). This forest NPP can also be a reflection of its sensitivity to, and its ability to adapt to, any climate change while also being harvested by humans. However detecting and identifying the vulnerability of forest and human ecosystems to climate change requires information on whether these coupled social and ecological systems are able to maintain functionality while responding to environmental variability. To better understand what parameters might be representative of environmental variability, we compiled a metadata analysis of 96 tropical forest sites. We found that three soil textural classes (i.e., sand, sandy loam and clay) had significant but different relationships between NPP and precipitation levels. Therefore, assessing the vulnerability of forests and forest dependent communities to drought was carried out using data from those sites that had one of those three soil textural classes. For example, forests growing on soil textures of sand and clay had NPP levels decreasing as precipitation levels increased, in contrast to those forest sites that had sandy loam soils where NPP levels increased. Also, forests growing on sandy loam soil textures appeared better adapted to grow at lower precipitation levels compared to the sand and clay textured soils. In fact in our tropical database the lowest precipitation level found for the sandy loam soils was 821 mm yr(-1) compared to sand at 1739 mm yr(-1) and clay at 1771 mm yr(-1). Soil texture also determined the level of NPP reached by a forest, i.e., forest growing on sandy loam and clay reached low-medium NPP levels while higher NPP levels (i.e., medium, high) were found on sand-textured soils. Intermediate precipitation levels (>1800-3000 mm yr(-1)) were needed to grow forests at the medium and high NPP levels. Low thresholds of NPP were identified at both low (∼750 mm) and high precipitation (>3500 mm) levels. By combining data on the ratios of precipitation to the amount of biomass produced in a year with how much less precipitation input occurs during a drought year, it is possible to estimate whether productivity levels are sufficient to support forest growth and forest dependent communities following a drought. In this study, the ratios of annual precipitation inputs required to produce 1 Mg ha(-1) yr(-1) biomass by soil texture class varied across the three soil textural classes. By using a conservative estimate of 20% of productivity collected or harvested by people and 30% precipitation reduction level as triggering a drought, it was possible to estimate a potential loss of annual productivity due to a drought. In this study, the total NPP unavailable due to drought and harvest by forest dependent communities per year was 10.2 Mg ha(-1) yr(-1) for the sandy textured soils (64% of NPP still available), 8.4 Mg ha(-1) yr(-1) for the sandy loam textured soils (60% available) and 12.7 Mg ha(-1) yr(-1) for the clay textured soils (29% available). Forests growing on clay textured soils would be most vulnerable to drought triggered reductions in productivity so NPP levels would be inadequate to maintain ecosystem functions and would potentially cause a forest-to-savanna shift. Further, these forests would not be able to provide sufficient NPP to satisfy the requirements of forest dependent communities. By predicting the productivity responses of different tropical forest ecosystems to changes in precipitation patterns coupled with edaphic data, it could be possible to spatially identify where tropical forests are most vulnerable to climate change impacts and where mitigation efforts should be concentrated. Copyright © 2015 Elsevier Inc. 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.

A geophysical and biochemical investigation of buried remains in contrasting soil textures in southern Ontario

NASA Astrophysics Data System (ADS)

Lowe, Amanda C.

Ground penetrating radar (GPR) is a non-invasive, geophysical tool used for the detection of clandestine graves. GPR operates by detecting density differences in soil by the transmission of high frequency electromagnetic (EM) waves from an antenna. A 500 Megahertz (MHz) frequency antenna is typically used for forensic investigations, as it provides a suitable compromise between depth of penetration and sub-surface resolution. Domestic pig (Sus scrofa) carcasses were clothed in 100% cotton t-shirts and 50% cotton/50% polyester briefs, and buried at a consistent depth at three field sites of contrasting soil texture (silty clay loam, fine sand and fine sandy loam) in southern Ontario. GPR was used to detect and monitor the graves for a period of 14 months post burial. Analysis of collected data revealed that GPR had applicability in the detection of clandestine graves containing remains in silty clay loam and fine sandy loam soils, but was not suitable for detection in fine sandy soil. Specifically, within a fine sandy loam soil, there is the potential to estimate the post burial interval (PBI), as hyperbolic grave response was well defined at the beginning of the 14 month burial duration, but became less distinctive near the completion of the study. Following the detection of a clandestine grave containing a carcass, collection of gravesoil, tissue and textile samples is important for the estimation of the stage of decomposition and the post burial interval (PBI) of the remains. Throughout the decomposition process of a carcass, adipose tissue is subjected to hydrolytic enzymes that convert triglycerides to their corresponding unsaturated, saturated and salts of fatty acids. The composition of fatty acids in the decomposed tissue will vary with the post mortem period, but it is unknown what affect the soil texture has on lipid degradation. As decomposition proceeds, fatty acids can leach from the tissues into the surrounding burial environment. Fatty acid analysis of gravesoil, tissue and textile samples, exhumed at two, eleven and fourteen month post burial intervals, was conducted using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and gas chromatography-mass spectrometry (GC-MS). Infrared (IR) spectroscopy analysis of the samples provided a qualitative profile of lipid degradation. Analysis of gravesoil samples did not reveal IR spectroscopy bands attributable to fatty acid degradation or adipocere formation. IR spectroscopy analysis of tissue samples is applicable for the estimation of carcass decomposition in all of the soil textures tested. Results of textile IR spectroscopy analysis revealed limited potential to estimate the stage of carcass decomposition in silty clay loam soil. GC-MS was used to quantify the peak area ratio (area/int std area) (PAR) of myristic (C14:0), palmitic (C16:0), palmitoleic (C16:1), stearic (C18:0) and oleic (C18:1) acids. GC-MS results revealed that analysis of both tissue and textile samples can be useful in the estimation of the stage of decomposition and the PBI of carcasses in all three of the soil textures tested. The results of this research may have applicability within forensic investigations involving decomposing bodies by aiding in the location of clandestine graves in silty clay loam and fine sandy loam soil through the use of GPR. Infrared spectroscopy and GC-MS analysis of the fatty acid composition of tissue and textile samples may also be incorporated into investigational protocols to aid in the estimation of the stage of decomposition and the PBI of a body. Key Words: forensic science, ground penetrating radar, soil texture, buried remains, fatty acids, gas chromatography-mass spectrometry (GC-MS), infrared spectroscopy

A Note on the Fractal Behavior of Hydraulic Conductivity and Effective Porosity for Experimental Values in a Confined Aquifer

PubMed Central

De Bartolo, Samuele; Fallico, Carmine; Veltri, Massimo

2013-01-01

Hydraulic conductivity and effective porosity values for the confined sandy loam aquifer of the Montalto Uffugo (Italy) test field were obtained by laboratory and field measurements; the first ones were carried out on undisturbed soil samples and the others by slug and aquifer tests. A direct simple-scaling analysis was performed for the whole range of measurement and a comparison among the different types of fractal models describing the scale behavior was made. Some indications about the largest pore size to utilize in the fractal models were given. The results obtained for a sandy loam soil show that it is possible to obtain global indications on the behavior of the hydraulic conductivity versus the porosity utilizing a simple scaling relation and a fractal model in coupled manner. PMID:24385876

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.

Evaluation of the effects of mulch on optimum sowing date and irrigation management of zero till wheat in central Punjab, India using APSIM.

PubMed

Balwinder-Singh; Humphreys, E; Gaydon, D S; Eberbach, P L

2016-10-01

Machinery for sowing wheat directly into rice residues has become more common in the rice-wheat systems of the north-west Indo-Gangetic Plains of South Asia, with increasing numbers of farmers now potentially able to access the benefits of residue retention. However, surface residue retention affects soil water and temperature dynamics, thus the optimum sowing date and irrigation management for a mulched crop may vary from those of a traditional non-mulched crop. Furthermore, the effects of sowing date and irrigation management are likely to vary with soil type and seasonal conditions. Therefore, a simulation study was conducted using the APSIM model and 40 years of weather data to evaluate the effects of mulch, sowing date and irrigation management and their interactions on wheat grain yield, irrigation requirement (I) and water productivity with respect to irrigation (WP I ) and evapotranspiration (WP ET ). The results suggest that the optimum wheat sowing date in central Punjab depends on both soil type and the presence or absence of mulch. On the sandy loam, with irrigation scheduled at 50% soil water deficit (SWD), the optimum sowing date was late October to early November for maximising yield, WP I and WP ET . On the clay loam, the optimum date was about one week later. The effect of mulch on yield varied with seasonal conditions and sowing date. With irrigation at 50% SWD, mulching of wheat sown at the optimum time increased average yield by up to 0.5 t ha -1 . The beneficial effect of mulch on yield increased to averages of 1.2-1.3 t ha -1 as sowing was advanced to 15 October. With irrigation at 50% SWD and 7 November sowing, mulch reduced the number of irrigations by one in almost 50% of years, a reduction of about 50 mm on the sandy loam and 60 mm on the clay loam. The reduction in irrigation amount was mainly due to reduced soil evaporation. Mulch reduced irrigation requirement by more as sowing was delayed, more so on the sandy loam than the clay loam soil. There was little effect of mulch on irrigation requirement for late October sowings. There were large trade-offs between irrigation input, yield, WP ET and WP I on the sandy loam with regard to the optimum irrigation schedule. Maximum yield occurred with very frequent irrigation (10-20% SWD) which also had the greatest irrigation input, while WP I was highest with least frequent irrigation (70% SWD), and WP ET was highest with irrigation at 40-50% SWD. This was the case with and without mulch. On the clay loam, the trade-offs were not so pronounced, as maximum yield was reached with irrigation at 50% SWD, with and without mulch. However, both WP ET and WP I were maximum and irrigation input least at the lowest irrigation frequency (70% SWD). On both soils, maximum yield, WP ET and WP I were higher with mulch, while irrigation input was slightly lower, but mulch had very little effect on the irrigation thresholds at which each parameter was maximised.

Investigating the Effect of Compaction Characteristics on the Erodibility of Cohesive Soils Using the JET Method

NASA Astrophysics Data System (ADS)

Asghari Tabrizi, A.; LaRocque, L. A.; Chaudhry, M.; Imran, J.

2013-12-01

Several flood disasters occur every year all over the world, mostly due to levee and dam failure which result in human fatalities as well as devastating economic damages. To model and predict earthen embankment failures for the preparation of emergency action plans and risk assessments, the soil erodibility by flowing water is an essential parameter. The determination of erodibility becomes even more complicated for cohesive soils because of the large number of parameters controlling their erosion behavior (e.g. clay content, plasticity, compaction effort, compaction water content) and the difficulty of estimating these parameters. In this study the effect of the compaction energy and compaction water content on the erodibility of a sandy loam soil was assessed. Soil samples were prepared in a standard diameter compaction mold, 101.6 mm, for three levels of compaction effort and water content (i.e. low, medium, and high) with two replications for each case (18 tests total) and examined using the jet erosion test (JET). Observations from qualitative and statistical analyses of the data are: 1) a wide range of erodibility, from very erodible to very resistant, was produced by changes in the compaction characteristics; 2) for a given compaction energy, the erosion resistance based on the detachment rate coefficient kd tends to become minimum near the optimum compaction water content. On the dry side of optimum compaction water content, kd decreases with steep gradients by increasing the water content, while it increases with a flatter gradient on the wet side; 3) At a given water content, the soil erosion resistance increases with compaction efforts; 4) compaction water content influences soil erosibility more than compaction energy, especially on the dry side of the optimum compaction water content; and 5) for a given compaction effort, the critical shear stress increases with water content up to an optimum water content and then it decreases which is in consistent with the kd trends.

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

Removal of a mixture of pesticides by a Streptomyces consortium: Influence of different soil systems.

PubMed

Fuentes, María S; Raimondo, Enzo E; Amoroso, María J; Benimeli, Claudia S

2017-04-01

Although the use of organochlorine pesticides (OPs) is restricted or banned in most countries, they continue posing environmental and health concerns, so it is imperative to develop methods for removing them from the environment. This work is aimed to investigate the simultaneous removal of three OPs (lindane, chlordane and methoxychlor) from diverse types of systems by employing a native Streptomyces consortium. In liquid systems, a satisfactory microbial growth was observed accompanied by removal of lindane (40.4%), methoxychlor (99.5%) and chlordane (99.8%). In sterile soil microcosms, the consortium was able to grow without significant differences in the different textured soils (clay silty loam, sandy and loam), both contaminated or not contaminated with the OPs-mixture. The Streptomyces consortium was able to remove all the OPs in sterile soil microcosm (removal order: clay silty loam > loam > sandy). So, clay silty loam soil (CSLS) was selected for next assays. In non-sterile CSLS microcosms, chlordane removal was only about 5%, nonetheless, higher rates was observed for lindane (11%) and methoxychlor (20%). In CSLS slurries, the consortium exhibited similar growth levels, in the presence of or in the absence of the OPs-mixture. Not all pesticides were removed in the same way; the order of pesticide dissipation was: methoxychlor (26%)>lindane (12.5%)>chlordane (10%). The outlines of microbial growth and pesticides removal provide information about using actinobacteria consortium as strategies for bioremediation of OPs-mixture in diverse soil systems. Texture of soils and assay conditions (sterility, slurry formulation) were determining factors influencing the removal of each pesticide of the mixture. Copyright © 2017 Elsevier Ltd. All rights reserved.

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%.

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.

[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.

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

Comparison of germination and seed vigor of sunflower in two contaminated soils of different texture

NASA Astrophysics Data System (ADS)

Zhao, Xin; Han, Jaemaro; Lee, Jong Keun; Kim, Jae Young

2014-05-01

Phytoremediation as an emerging low-cost and ecologically friendly alternative to the conventional soil remediation technologies has gained a great deal of attention and into lots of research. As a kind of the methods that use of green plants to remediate heavy metals contaminated soils, the early growth status of plant seeds in the contaminated environmental directly affects the effect of phytoremediation. Germination test in the water (aqueous solution of heavy metal) is generally used for assessing heavy metal phytotoxicity and possibility of plant growth, but there is a limit. Because soil is commonly main target of phytoremediation, not the water. The bioavailability of heavy metals in the soil also depends on the texture. So soil texture is an important factor of phytoremediation effect. Sunflower is the representative species which have good tolerance to various heavy metals; furthermore, the seeds of sunflower can be used as the raw-material for producing bio-diesel. The objectives of this research were to investigate germination rate of sunflowers in various heavy metal contaminated soils and to compare the seedling vigor index (SVI) of sunflower in two contaminated soils of different texture. Sunflower (Helianthusannuus L.) seeds were obtained from a commercial market. In order to prove the soil texture effect on heavy metal contaminated soil, germination tests in soil were conducted with two different types of soil texture (i.e., loam soil and sandy loam soil) classified by soil textural triangle (defined by USDA) including representative soil texture of Korea. Germination tests in soil were conducted using KS I ISO 11260-1 (2005) for reference that sunflower seeds were incubated for 7 days in dark at 25 ± 1 Celsius degree. The target heavy metals are Nickel (Ni) and Zinc (Zn). The Ni and Zn concentrations were 0, 10, 50, 100, 200, 300, 500 mg-Ni/kg-dry soil, and 0, 10, 50, 100, 300, 500, 900 mg-Zn/kg-dry soil, respectively. After germination test for 7 days, germination rate of sunflower was calculated, and shoot and root lengths were also measured. According to the results of germination tests, the seeds germination rates were reduced with increasing heavy metal concentrations in both loam soil and sandy loam soil. The SVI values in loam soil in more than in sandy loam soil. Keywords: phytoremediation, sunflower, soil texture, germination test ACKNOWLEDGEMENT This work is supported by the Korea Ministry of the Environment as 'The GAIA (Geo-Advanced Innovative Action) Project'.

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 account in furthering our understanding of NVS activities for M. hapla management. Copyright 2010 Elsevier Ltd. All rights reserved.

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 would decrease P solubility and might at large application rates hamper P uptake by plants or, on the other hand, the sediment amendment in the soil might reduce P losses by runoff.

Nutrient and Antinutrient Compositions and Heavy Metal Uptake and Accumulation in S. nigrum Cultivated on Different Soil Types

PubMed Central

Ogundola, Adijat Funke; Bvenura, Callistus

2018-01-01

Solanum nigrum cultivated on different soil texture types, sandy clay loam, silty clay loam, clay loam, loam, and control soils, were evaluated for proximate compositions, antinutrients, vitamins, and mineral composition with plant age using standard analytical methods. Accumulation of trace elements using translocation factor was studied to determine their toxic levels in plant tissues. Data were analysed by ANOVA and results expressed as means and standard deviation. Ash content, crude fibre, protein, alkaloid, phytate, and saponin ranged between 11.4 and 12%, 19.24 and 19.95%, 34.23 and 38.98, 42.08 and 45.76 mg/ml, 0.84 and 1.17%, and 94.10 and 97.00%, respectively. Vitamins A, C, and B were present in high quantity. Macro- and micronutrients recorded showed that S. nigrum is a potential reservoir of minerals. Accumulation of micronutrients was observed to be the highest at the flowering stage between the 4th and 5th weeks after transplanting. Plants cultivated on clay loam, silty clay loam, and loam soils accumulated elevated nutritional compositions and abundant antinutrients. However, the accumulated trace metals in the plants are within the recommended safe levels. All nutrient values are in the recommended requirements for daily consumption. PMID:29576752

Effect of surfactants on sorption of atrazine by soil

NASA Astrophysics Data System (ADS)

Abu-Zreig, Majed; Rudra, R. P.; Dickinson, W. T.; Evans, L. J.

1999-03-01

This study investigates the effect of synthetic wastewater containing surfactants on the sorption of atrazine using an equilibrium batch technique. Laboratory experiments were conducted on three soils with two non-ionic (Rexol and Rexonic) surfactants and one anionic (Sulphonic) surfactant, specifically manufactured for the detergent industry. Four sets of experiments were conducted to examine the influence of surfactants on the equilibrium time of atrazine sorption, to explore the effect of surfactant concentration, pH and type of surfactant on the amount of atrazine sorbed and to determine sorption isotherms of atrazine in the presence of surfactants. The results indicate that the application of Sulphonic results in dramatic increase in the adsorption of atrazine on to soils, the increase being directly proportional to the concentration of the surfactant. Application of the Sulphonic surfactants with a concentration of 3000 mg/l can result in a significant increase in Kd values of atrazine for loam and sandy loam soils. On the other hand, the effect of non-ionic surfactants depends on their concentration. Generally, non-ionic surfactants can result in a slight increase in atrazine sorption at high concentration, an exception being Rexol on sandy loam soil. At low concentrations, non-ionic surfactants have shown a tendency to decrease atrazine sorption.

Cadmium phytoextraction from loam soil in tropical southern China by Sorghum bicolor.

PubMed

Wang, Xu; Chen, Can; Wang, Jianlong

2017-06-03

The cadmium (Cd) uptake characteristics by Sorghum bicolor cv. Nengsi 2# and Cowley from the acidic sandy loam soil (pH = 6.1) during the entire growth period (100 days) were investigated in pot outdoors in a tropical district of southern China, Hainan Island. The Cd-spiked levels in soil were set as 3 and 15 mg/kg. Correspondingly, the available Cd levels in soil extracted by Mehlich III solution were 2.71 and 9.41 mg/kg, respectively. Basically, two varieties in a full growth period (100 days) did not show a significant difference in their growth and Cd uptake. Under high Cd stress, the plant growth was inhibited and its biomass weight and height decreased by 38.7-51.5% and 27.6-28.5%, respectively. However, S. bicolor showed higher bioaccumulation capability of Cd from soil to plant [bioconcentration factor (BCF)>4], and higher transfer capability of Cd from roots to shoots [translocation factor (TF)>1] under high Cd stress; Cd contents in the roots, stems, and leaves of S. bicolor reached 43.79-46.07, 63.28-70.60, and 63.10-66.06 mg/kg, respectively. S. bicolor exhibited the potential phytoextraction capability for low or moderate Cd-contamination in acidic sandy loam soil.

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.

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.

Multilaboratory evaluation of methods for detecting enteric viruses in soils.

PubMed Central

Hurst, C J; Schaub, S A; Sobsey, M D; Farrah, S R; Gerba, C P; Rose, J B; Goyal, S M; Larkin, E P; Sullivan, R; Tierney, J T

1991-01-01

Two candidate methods for the recovery and detection of viruses in soil were subjected to round robin comparative testing by members of the American Society for Testing and Materials D19:24:04:04 Subcommittee Task Group. Selection of the methods, designated "Berg" and "Goyal," was based on results of an initial screening which indicated that both met basic criteria considered essential by the task group. Both methods utilized beef extract solutions to achieve desorption and recovery of viruses from representative soils: a fine sand soil, an organic muck soil, a sandy loam soil, and a clay loam soil. One of the two methods, Goyal, also used a secondary concentration of resulting soil eluants via low-pH organic flocculation to achieve a smaller final assay volume. Evaluation of the two methods was simultaneously performed in replicate by nine different laboratories. Each of the produced samples was divided into portions, and these were respectively subjected to quantitative viral plaque assay by both the individual, termed independent, laboratory which had done the soil processing and a single common reference laboratory, using a single cell line and passage level. The Berg method seemed to produce slightly higher virus recovery values; however, the differences in virus assay titers for samples produced by the two methods were not statistically significant (P less than or equal to 0.05) for any one of the four soils. Despite this lack of a method effect, there was a statistically significant laboratory effect exhibited by assay titers from the independent versus reference laboratories for two of the soils, sandy loam and clay loam. PMID:1849712

Multilaboratory evaluation of methods for detecting enteric viruses in soils.

PubMed

Hurst, C J; Schaub, S A; Sobsey, M D; Farrah, S R; Gerba, C P; Rose, J B; Goyal, S M; Larkin, E P; Sullivan, R; Tierney, J T

1991-02-01

Two candidate methods for the recovery and detection of viruses in soil were subjected to round robin comparative testing by members of the American Society for Testing and Materials D19:24:04:04 Subcommittee Task Group. Selection of the methods, designated "Berg" and "Goyal," was based on results of an initial screening which indicated that both met basic criteria considered essential by the task group. Both methods utilized beef extract solutions to achieve desorption and recovery of viruses from representative soils: a fine sand soil, an organic muck soil, a sandy loam soil, and a clay loam soil. One of the two methods, Goyal, also used a secondary concentration of resulting soil eluants via low-pH organic flocculation to achieve a smaller final assay volume. Evaluation of the two methods was simultaneously performed in replicate by nine different laboratories. Each of the produced samples was divided into portions, and these were respectively subjected to quantitative viral plaque assay by both the individual, termed independent, laboratory which had done the soil processing and a single common reference laboratory, using a single cell line and passage level. The Berg method seemed to produce slightly higher virus recovery values; however, the differences in virus assay titers for samples produced by the two methods were not statistically significant (P less than or equal to 0.05) for any one of the four soils. Despite this lack of a method effect, there was a statistically significant laboratory effect exhibited by assay titers from the independent versus reference laboratories for two of the soils, sandy loam and clay loam.

New technology N products in alabama

USDA-ARS?s Scientific Manuscript database

Because of high fertilizer N prices, growers are interested in using less expensive sources of N and using fertilizer additives to reduce ammonia volatilization losses from urea sources. An experiment on a Lucedale fine sandy loam in Central Alabama (Prattville Research Unit) was conducted in 2007 ...

Evaluation of N products for cotton and corn

USDA-ARS?s Scientific Manuscript database

Because of high fertilizer N prices, growers are interested in using less expensive sources of N and using fertilizer additives to reduce ammonia volatilization losses from urea sources. An experiment on a Lucedale fine sandy loam (fine-loamy, siliceous, thermic Rhodic Paleudults) in Central Alabam...

New technology N products in alabama

USDA-ARS?s Scientific Manuscript database

Because of high fertilizer N prices, growers are interested in using less expensive sources of N and using fertilizer additives to reduce ammonia volatilization losses from urea sources. An experiment on a Lucedale fine sandy loam in Central Alabama (Prattville Research Unit) was conducted in 2007 t...

Suppression of cheatgrass by established perennial grasses: I. mechanisms

USDA-ARS?s Scientific Manuscript database

Cheatgrass is often considered a competitive species. In a greenhouse experiment using rhizotrons, we tested the effect of established perennial grasses (Indian ricegrass, creeping wildrye, and Snake River wheatgrass) on the growth of cheatgrass. The soil was a sandy loam A horizon of a Xeric Haploc...

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...

Monitoring the performance of an alternative cover using caisson lysimeters

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

Waugh, W.J.; Smith, G.M.; Mushovic, P.S.

2004-02-29

The U.S. Department of Energy (DOE) office in Grand Junction, Colorado, and the U.S. Environmental Protection Agency (EPA), Region 8, collaborated on a series of field lysimeter studies to design and monitor the performance of an alternative cover for a uranium mill tailings disposal cell at the Monticello, Utah, Superfund Site. Because groundwater recharge is naturally limited at Monticello in areas with thick loess soils, DOE and EPA chose to design a cover for Monticello using local soils and a native plant community to mimic this natural soilwater balance. Two large drainage lysimeters fabricated of corrugated steel culvert lined withmore » high-density polyethylene were installed to evaluate the hydrological and ecological performance of an alternative cover design constructed in 2000 on the disposal cell. Unlike conventional, lowpermeability designs, this cover relies on (1) the water storage capacity of a 163-cm soil “sponge” layer overlying a sand-and-gravel capillary barrier to retain precipitation while plants are dormant and (2) native vegetation to remove precipitation during the growing season. The sponge layer consists of a clay loam subsoil compacted to 1.65 g/cm2 in one lysimeter and a loam topsoil compacted to 1.45 g/cm2 in the other lysimeter, representing the range of as-built conditions constructed in the nearby disposal cell cover. About 0.1 mm of drainage occurred in both lysimeters during an average precipitation year and before they were planted, an amount well below the EPA target of <3.0 mm/yr. However, the cover with less compacted loam topsoil sponge had a 40% greater water storage capacity than the cover with overly compacted clay loam subsoil sponge. The difference is attributable in part to higher green leaf area and water extraction by plants in the loam topsoil. The lesson learned is that seemingly subtle differences in soil types, sources, and compaction can result in salient differences in performance. Diverse, seeded communities of predominantly native perennial species were established on both lysimeters during an extended 3-yr drought, highlighting the importance of a sound understanding of the local ecology and of implementing the science and methods of disturbed-land revegetation.« less

The impact of biosolids application on organic carbon and carbon dioxide fluxes in soil.

PubMed

Wijesekara, Hasintha; Bolan, Nanthi S; Thangavel, Ramesh; Seshadri, Balaji; Surapaneni, Aravind; Saint, Christopher; Hetherington, Chris; Matthews, Peter; Vithanage, Meththika

2017-12-01

A field study was conducted on two texturally different soils to determine the influences of biosolids application on selected soil chemical properties and carbon dioxide fluxes. Two sites, located in Manildra (clay loam) and Grenfell (sandy loam), in Australia, were treated at a single level of 70 Mg ha -1 biosolids. Soil samples were analyzed for SOC fractions, including total organic carbon (TOC), labile, and non-labile carbon contents. The natural abundances of soil δ 13 C and δ 15 N were measured as isotopic tracers to fingerprint carbon derived from biosolids. An automated soil respirometer was used to measure in-situ diurnal CO 2 fluxes, soil moisture, and temperature. Application of biosolids increased the surface (0-15 cm) soil TOC by > 45% at both sites, which was attributed to the direct contribution from residual carbon in the biosolids and also from the increased biomass production. At both sites application of biosolids increased the non-labile carbon fraction that is stable against microbial decomposition, which indicated the soil carbon sequestration potential of biosolids. Soils amended with biosolids showed depleted δ 13 C, and enriched δ 15 N indicating the accumulation of biosolids residual carbon in soils. The in-situ respirometer data demonstrated enhanced CO 2 fluxes at the sites treated with biosolids, indicating limited carbon sequestration potential. However, addition of biosolids on both the clay loam and sandy loam soils found to be effective in building SOC than reducing it. Soil temperature and CO 2 fluxes, indicating that temperature was more important for microbial degradation of carbon in biosolids than soil moisture. Copyright © 2017 Elsevier Ltd. All rights reserved.

Combined effects of tides, evaporation and rainfall on the soil conditions in an intertidal creek-marsh system

NASA Astrophysics Data System (ADS)

Xin, Pei; Zhou, Tingzhang; Lu, Chunhui; Shen, Chengji; Zhang, Chenming; D'Alpaos, Andrea; Li, Ling

2017-05-01

Salt marshes, distributed globally at the land-ocean interface, are a highly productive eco-system with valuable ecological functions. While salt marshes are affected by various eco-geo-hydrological processes and factors, soil moisture and salinity affect plant growth and play a key role in determining the structure and functions of the marsh ecosystem. To examine the variations of both soil parameters, we simulated pore-water flow and salt transport in a creek-marsh system subjected to spring-neap tides, evaporation and rainfall. The results demonstrated that within a sandy-loam marsh, the tide-induced pore-water circulation averted salt build-up due to evaporation in the near-creek area. In the marsh interior where the horizontal drainage was weak, density-driven flow was responsible for dissipating salt accumulation in the shallow soil layer. In the sandy-loam marsh, the combined influences of spring-neap tides, rainfall and evaporation led to the formation of three characteristic zones, c.f., a near-creek zone with low soil water saturation (i.e., well-aerated) and low pore-water salinity as affected by the semi-diurnal spring tides, a less well-aerated zone with increased salinity where drainage occurred during the neap tides, and an interior zone where evaporation and rainfall infiltration regulated the soil conditions. These characteristics, however, varied with the soil type. In low-permeability silt-loam and clay-loam marshes, the tide-induced drainage weakened and the soil conditions over a large area became dominated by evaporation and rainfall. Sea level rise was found to worsen the soil aeration condition but inhibit salt accumulation due to evaporation. These findings shed lights on the soil conditions underpinned by various hydrogeological processes, and have important implications for further investigations on marsh plant growth and ecosystem functions.

Altered humin compositions under organic and inorganic fertilization on an intensively cultivated sandy loam soil

USDA-ARS?s Scientific Manuscript database

Humin is the largest and also the least understood fraction of soil organic matter. The humin structure and its correlation with microbiological properties are particularly uncertain. We applied advanced solid-state 13C nuclear magnetic resonance (NMR) spectroscopy to investigate the structural chan...

Evidence For Different Reaction Pathways For Liquid And Granular Micronutrients In A Calcareous Soil

EPA Science Inventory

The benefits of Mn and Zn fluid fertilizers over conventional granular products in calcareous sandy loam soils have been agronomically demonstrated. We hypothesized that the differences in the effectiveness between granular and fluid Mn and Zn fertilizers is due to different Mn ...

Plant, soil and weather based cues for irrigation timing in soybean production 2014

USDA-ARS?s Scientific Manuscript database

Expanded use of irrigation management tools are needed to improve irrigation and water use efficiency in eastern Arkansas soybean production. In 2014 we initiated an Arkansas Soybean Promotion Board supported project to examine irrigation initiation timing on a sandy loam soil in a furrow-irrigated ...

Parameterization of norfolk sandy loam properties for stochastic modeling of light in-wheel motor UGV

USDA-ARS?s Scientific Manuscript database

To accurately develop a mathematical model for an In-Wheel Motor Unmanned Ground Vehicle (IWM UGV) on soft terrain, parameterization of terrain properties is essential to stochastically model tire-terrain interaction for each wheel independently. Operating in off-road conditions requires paying clos...

Water Storage and Related Physical Characteristics of Four Mineral Soils in North Central Minnesota

Treesearch

E. S. Verry

1969-01-01

Soil water storage in a 7.5 foot profile varied nearly 100 percent (7.9 to 15.5 inches) among four mineral soils ranging from a sand to sandy loam. Bulk density, size fractions, and four water retention values are tabulated for each horizon.

Evaluation of factors affecting nitrous oxide emission and N transformation in a sandy loam soil

USDA-ARS?s Scientific Manuscript database

A better understanding of the complex factors affecting nitrous oxide (N2O) emission and potential mitigation practices will assist in developing strategies to improve the sustainability of agricultural production systems. Using surface soil collected from a pomegranate orchard, a series of laborato...

Rates of forest floor decomposition and nutrient turnover in aspen, pine, and spruce stands on two soils.

Treesearch

D. A. Perala; D.H. Alban

1982-01-01

Compares rates of forest floor decomposition and nutrient turnover in aspen and conifers. These rates were generally most rapid under aspen, slowest under spruce, and more rapid on a loamy fine sand than on a very fine sandy loam. Compares results with literature values.

THE PHYTOAVAILABILITY OF CADMIUM TO LETTUCE IN LONG-TERM BIOSOLIDS-AMENDED SOILS

EPA Science Inventory

A field study was conducted to assess the phytoavailability of Cd in long-term biosolids-amended field plots managed at high and low pH. The experiment, established 13-15 yr prior to the present cropping, on a Christiana fine sandy loam soil (a clayey, kaolinitic, mesic Typic Pa...

Cotton Cultivar Response to Root-Knot Nematodes in Two Tillage Regimes, 2008

USDA-ARS?s Scientific Manuscript database

Six cotton cultivars were evaluated for yield response to the root-knot nematode in a naturally infested field at E. V. Smith Research and Extension Center, near Shorter, Alabama. The field had a long history of root-knot nematode infestation, and the soil type was classified as a sandy loam. Plots ...

Apple rootstock evaluation for apple replant disease

USDA-ARS?s Scientific Manuscript database

Twenty-nine rootstocks from the Cornell-Geneva rootstock breeding program, some Budagovski rootstocks, M.9T337 and M.26EMLA were screened for apple replant disease (ARD) tolerance at Geneva, New York in 2008. Bench grafted rootstocks were planted in pots with two types of soil –clay loam and sandy l...

Effect of alternative surface inlet designs on sediment and phosphorus drainage losses

USDA-ARS?s Scientific Manuscript database

Open surface inlets that connect to subsurface tile drainage systems provide a direct pathway for sediment, nutrients, and agrochemicals to surface waters. This study was conducted to determine whether modifying open inlets by burying them in gravel capped with 30 cm of sandy clay loam soil or in ve...

Clinoptilolite zeolite influence on inorganic nitrogen in silt loam and sandy agricultural soils

USDA-ARS?s Scientific Manuscript database

Development of best management practices can help improve inorganic nitrogen (N) availability to plants and reduce nitrate-nitrogen (NO3-N) leaching in soils. This study was conducted to determine the influence of the zeolite mineral Clinoptilolite (CL) additions on NO3-N and ammonium-nitrogen (NH4...

Clinoptilolite Zeolite Influence on Inorganic Nitrogen in Silt Loam and Sandy Agricultural Soils

USDA-ARS?s Scientific Manuscript database

Development of best management practices can help improve inorganic nitrogen (N) availability to plants and reduce nitrate-nitrogen (NO3-N) leaching in soils. This study was conducted to determine the influence of the zeolite mineral Clinoptilolite (CL) additions on NO3-N and ammonium-nitrogen (NH4...

Eleventh-year results of fertilization, herbaceous, and woody plant control in a loblolly pine plantation

Treesearch

James D. Haywood; Allan E. Tiarks

1990-01-01

Through 11 years, fertilization at planting significantly increased the stemwood volume (outside bark) per loblolly pine (Pinus taeda L.) on an intensively prepared moderately well-drained fine sandy loam site in northern Louisiana. Four years of herbaceous plant control significantly increased pine survival, and because herbaceous plant control...

Finding of No Significant Impact: Expand RV Storage Lot United States Air Force Academy, CO

DTIC Science & Technology

2006-09-18

the surface layer is grayish brown gravelly sandy loam about 14 inches thick. The underlying material is light yellowish brown gravelly loamy sand...inhibit the urease activity of soil microbes by up to 47% and 35%, respectively, suggesting that sources of nitrogen other than urea should be used

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...

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.

Evaluation of on-site wastewater system Escherichia coli contributions to shallow groundwater in coastal North Carolina.

PubMed

Humphrey, C P; O'Driscoll, M A; Zarate, M A

2011-01-01

The study goal was to determine if on-site wastewater systems (OSWWS) installed in coastal areas were effective at reducing indicator bacteria densities before discharge to groundwater. Groundwater Escherichia coli (E. coli) densities and groundwater levels adjacent to 16 OSWWS in three different soil groups (sand, sandy loam, and sandy clay loam) were monitored and compared to background groundwater conditions on four occasions between March 2007 and February 2008 in coastal North Carolina. Groundwater beneath OSWWS had significantly (p≤0.05) lower densities of E. coli than septic tank effluent, but significantly higher densities of E. coli than background conditions for each soil type. Twenty three percent of all groundwater samples near OSWWS had E. coli densities that exceeded the EPA freshwater contact standards (single sample 235 cfu/100 mL) for surface waters. Groundwater E. coli densities near OSWWS were highest during shallow water table periods. The results indicate that increasing the required vertical separation distance from drainfield trenches to seasonal high water table could improve shallow groundwater quality.

Ammonia oxidation pathways and nitrifier denitrification are significant sources of N2O and NO under low oxygen availability

PubMed Central

Zhu, Xia; Burger, Martin; Doane, Timothy A.; Horwath, William R.

2013-01-01

The continuous increase of nitrous oxide (N2O) abundance in the atmosphere is a global concern. Multiple pathways of N2O production occur in soil, but their significance and dependence on oxygen (O2) availability and nitrogen (N) fertilizer source are poorly understood. We examined N2O and nitric oxide (NO) production under 21%, 3%, 1%, 0.5%, and 0% (vol/vol) O2 concentrations following urea or ammonium sulfate [(NH4)2SO4] additions in loam, clay loam, and sandy loam soils that also contained ample nitrate. The contribution of the ammonia (NH3) oxidation pathways (nitrifier nitrification, nitrifier denitrification, and nitrification-coupled denitrification) and heterotrophic denitrification (HD) to N2O production was determined in 36-h incubations in microcosms by 15N-18O isotope and NH3 oxidation inhibition (by 0.01% acetylene) methods. Nitrous oxide and NO production via NH3 oxidation pathways increased as O2 concentrations decreased from 21% to 0.5%. At low (0.5% and 3%) O2 concentrations, nitrifier denitrification contributed between 34% and 66%, and HD between 34% and 50% of total N2O production. Heterotrophic denitrification was responsible for all N2O production at 0% O2. Nitrifier denitrification was the main source of N2O production from ammonical fertilizer under low O2 concentrations with urea producing more N2O than (NH4)2SO4 additions. These findings challenge established thought attributing N2O emissions from soils with high water content to HD due to presumably low O2 availability. Our results imply that management practices that increase soil aeration, e.g., reducing compaction and enhancing soil structure, together with careful selection of fertilizer sources and/or nitrification inhibitors, could decrease N2O production in agricultural soils. PMID:23576736

Ammonia oxidation pathways and nitrifier denitrification are significant sources of N2O and NO under low oxygen availability.

PubMed

Zhu, Xia; Burger, Martin; Doane, Timothy A; Horwath, William R

2013-04-16

The continuous increase of nitrous oxide (N2O) abundance in the atmosphere is a global concern. Multiple pathways of N2O production occur in soil, but their significance and dependence on oxygen (O2) availability and nitrogen (N) fertilizer source are poorly understood. We examined N2O and nitric oxide (NO) production under 21%, 3%, 1%, 0.5%, and 0% (vol/vol) O2 concentrations following urea or ammonium sulfate [(NH4)2SO4] additions in loam, clay loam, and sandy loam soils that also contained ample nitrate. The contribution of the ammonia (NH3) oxidation pathways (nitrifier nitrification, nitrifier denitrification, and nitrification-coupled denitrification) and heterotrophic denitrification (HD) to N2O production was determined in 36-h incubations in microcosms by (15)N-(18)O isotope and NH3 oxidation inhibition (by 0.01% acetylene) methods. Nitrous oxide and NO production via NH3 oxidation pathways increased as O2 concentrations decreased from 21% to 0.5%. At low (0.5% and 3%) O2 concentrations, nitrifier denitrification contributed between 34% and 66%, and HD between 34% and 50% of total N2O production. Heterotrophic denitrification was responsible for all N2O production at 0% O2. Nitrifier denitrification was the main source of N2O production from ammonical fertilizer under low O2 concentrations with urea producing more N2O than (NH4)2SO4 additions. These findings challenge established thought attributing N2O emissions from soils with high water content to HD due to presumably low O2 availability. Our results imply that management practices that increase soil aeration, e.g., reducing compaction and enhancing soil structure, together with careful selection of fertilizer sources and/or nitrification inhibitors, could decrease N2O production in agricultural soils.

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.

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 © 2012 Elsevier Ltd. All rights reserved.

Microbial Community Structure and Enzyme Activities in Semiarid Agricultural Soils

NASA Astrophysics Data System (ADS)

Acosta-Martinez, V. A.; Zobeck, T. M.; Gill, T. E.; Kennedy, A. C.

2002-12-01

The effect of agricultural management practices on the microbial community structure and enzyme activities of semiarid soils of different textures in the Southern High Plains of Texas were investigated. The soils (sandy clay loam, fine sandy loam and loam) were under continuous cotton (Gossypium hirsutum L.) or in rotations with peanut (Arachis hypogaea L.), sorghum (Sorghum bicolor L.) or wheat (Triticum aestivum L.), and had different water management (irrigated or dryland) and tillage (conservation or conventional). Microbial community structure was investigated using fatty acid methyl ester (FAME) analysis by gas chromatography and enzyme activities, involved in C, N, P and S cycling of soils, were measured (mg product released per kg soil per h). The activities of b-glucosidase, b-glucosaminidase, alkaline phosphatase, and arylsulfatase were significantly (P<0.05) increased in soils under cotton rotated with sorghum or wheat, and due to conservation tillage in comparison to continuous cotton under conventional tillage. Principal component analysis showed FAME profiles of these soils separated distinctly along PC1 (20 %) and PC2 (13 %) due to their differences in soil texture and management. No significant differences were detected in FAME profiles due to management practices for the same soils in this sampling period. Enzyme activities provide early indications of the benefits in microbial populations and activities and soil organic matter under crop rotations and conservation tillage in comparison to the typical practices in semiarid regions of continuous cotton and conventional tillage.

Effects of biochar addition to soil on nitrogen fluxes in a winter wheat lysimeter experiment

NASA Astrophysics Data System (ADS)

Hüppi, Roman; Leifeld, Jens; Neftel, Albrecht; Conen, Franz; Six, Johan

2014-05-01

Biochar is a carbon-rich, porous residue from pyrolysis of biomass that potentially increases crop yields by reducing losses of nitrogen from soils and/or enhancing the uptake of applied fertiliser by the crops. Previous research is scarce about biochar's ability to increase wheat yields in temperate soils or how it changes nitrogen dynamics in the field. In a lysimeter system with two different soils (sandy/silt loam) nitrogen fluxes were traced by isotopic 15N enriched fertiliser to identify changes in nitrous oxide emissions, leaching and plant uptake after biochar addition. 20t/ha woodchip-waste biochar (pH=13) was applied to these soils in four lysimeters per soil type; the same number of lysimeters served as a control. The soils were cropped with winter wheat during the season 2012/2013. 170 kg-N/ha ammonium nitrate fertiliser with 10% 15N was applied in 3 events during the growing season and 15N concentrations where measured at different points in time in plant, soil, leachate and emitted nitrous oxide. After one year the lysimeter system showed no difference between biochar and control treatment in grain- and straw yield or nitrogen uptake. However biochar did reduce nitrous oxide emissions in the silt loam and losses of nitrate leaching in sandy loam. This study indicates potential reduction of nitrogen loss from cropland soil by biochar application but could not confirm increased yields in an intensive wheat production system.

The effect of EDTA on Helianthus annuus uptake, selectivity, and translocation of heavy metals when grown in Ohio, New Mexico and Colombia soils.

PubMed

Turgut, Cafer; Pepe, M Katie; Cutright, Teresa J

2005-02-01

The use of two EDTA concentrations for enhancing the bioavailability of cadmium, chromium, and nickel in three natural soils (Ohio, New Mexico and Colombia) was investigated. The resulting uptake, translocation and selectivity with Helianthus annuus after mobilization were also examined. In general, plants grown in the sandy-loam Ohio soil had a higher uptake that resulted in a selectivity and total metal content of Cd>Cr>Ni and 0.73 mg and Cr>Cd>Ni and 0.32 mg for 0.1 and 0.3 g kg-1 EDTA, respectively. With the silty-loam New Mexico soil, although the total metal uptake was not statistically different the EDTA level did alter the selectivity; Cd>Cr>Ni (0.1 g kg-1 EDTA) and Cd>Cr>Ni (0.3 g kg-1 EDTA). Conversely, with the Colombian (sandy clay loam) soil increasing the EDTA level resulted in a higher total metal uptake (0.62 mg) than the 0.1 g kg-1 (0.59 mg) treatment. For all three soils, the translocation of Cd was limited. Evaluating the mobile metal fraction with and without EDTA determined that the chelator was capable of overcoming mass transfer limitations associated with the expandable clay fraction in the soils. Root wash results and root biomass concentrations indicated that Cd sorption was occurring. Therefore limited Cd translocation was attributed to insufficient phytochelatin levels.

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.

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 pattern in the temporal stability of tree growth was clearly related to that one in SWC. Nevertheless, the treatments that represent the mean conditions in growth were not exactly the same than those in SWC, which could be attributable to other characteristics than soil.

Comparative research on tillable properties of diatomite-improved soils in the Yangtze River Delta region, China.

PubMed

Qu, Ji-Li; Zhao, Dong-Xue

2016-10-15

To improve soil texture and structure, techniques associated with physical, biological or chemical aspects are generally adopted, among which diatomite is an important soil conditioner. However, few studies have been conducted to investigate the physical, hydraulic and tillage performance of diatomite-improved soils. Consistency limits and compaction properties were investigated in this study, and several performance indicators were compared, such as the liquid limit, plastic limit and compactability, of silt, silt loam and silty-clay loam soils to which diatomite was added at volumetric ratios of 0%, 10%, 20%, and 30%. The results showed that diatomite significantly (p<0.05) improved the consistency limits, with the most preferred effects in the silt soil. The liquid limits were increased by 53.9%, 27.3%, and 14.7%, in the silt, silt loam and silty-clay loam soils, respectively, when the volumetric ratio was 30%. While diatomite lowered the maximum dry bulk density (MBD) of the classified soils, the optimum moisture content (OMC) was increased overall. The trend was consistent with the proportion of diatomite, and MBD decreased by 8.7%, 10.3%, and 13.2% in the silt, silt loam and silty-clay loam soils when 30% diatomite was mixed, whereas OMC increased by 28.7%, 22.4%, and 25.3%, respectively. Additionally, aggregate stability was negatively correlated with MBD but positively correlated with OMC. Diatomite exerts positive effects on soil mechanical strength, suggesting that soils from sludge farms are more tillable with a larger stabilized and workable matrix. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

[Development of APSIM (agricultural production systems simulator) and its application].

PubMed

Shen, Yuying; Nan, Zhibiao; Bellotti, Bill; Robertson, Michael; Chen, Wen; Shao, Xinqing

2002-08-01

Soil-crop simulator model is an effective tool for providing decision on agricultural management. APSIM (Agricultural Production Systems Simulator) was developed to simulate the biophysical process in farming system, and particularly in the economic and ecological features of the systems under climatic risk. The current literatures revealed that APSIM could be applied in wide zone, including temperate continental, temperate maritime, sub-tropic and arid climate, and Mediterranean climates, with the soil type of clay, duplex soil, vertisol, silt sandy, silt loam and silt clay loam. More than 20 crops have been simulated well. APSIM is powerful on describing crop structure, crop sequence, yield prediction, and quality control as well as erosion estimation under different planting pattern.

Off-Site Movement of Picloram From A Coastal Plain Kudzu Site

Treesearch

Jerry L. Michael

1987-01-01

Picloram (4-amino-3,5,6-trichloro-picolinic acid) was aerially applied to a longleaf pine (Pinus palustris L.) site in the upper coastal plain of Alabama to control kudzu (Pueraria lobata (Willd.) Ohwi). Granules (10% ai [active ingredient]) were spread at a rate of 56 kg/ha to sandy loam Typic Paleudult soils. Movement was...

75 FR 41229 - Endangered and Threatened Wildlife and Plants; Permit, San Bernardino County, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-15

... scrub and sandy loam soils. Desert tortoise surveys were conducted on the property and two individuals... species has been recorded nearby and the property is within the range of and provides suitable habitat for... risks; (3) Approval of the HCP would not result in any cumulative or growth-inducing impacts and would...

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.

The effects of soil moisture, texture, and nutrient levels on the growth of black walnut.

Treesearch

Richard E. Dickson

1971-01-01

Black walnut seedlings grown in a clay loam and sandy soil were subjected to two soil moisture regimes and three fertility levels. Fertilization increased growth only under most conditions. Under draught, fertilization retarded growth in the sand. Nitrogen was the element primarily responsible for the greater growth under moist conditions.

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.

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

1,3-dichloropropene and chloropicrin emissions following simulated drip irrigation to raised beds under plastic films

USDA-ARS?s Scientific Manuscript database

Using laboratory soil chambers a non-scaled representation of an agricultural raised bed was constructed. For a sandy loam soil, a drip application of 1,3-dichloropropene (1,3-D) and chloropicrin (CP) under both high density polyethylene (HDPE) and virtually impermeable film (VIF) was performed at 5...

Belowground Processes in Nitrogen Fertilized Cottonwood and Loblolly Pine Plantations

Treesearch

Kye-Han Lee; Shibu Jose

2004-01-01

We measured soil respiration, fine root biomass production, and microbial biomass along a fertilization gradient (0, 56, 112, and 224 kg N ha-1 per year) in 7-year-old cottonwood and loblolly pine plantations, established on a well-drained, Redbay sandy loam (a fine-loamy, siliceous, thermic Rhodic Paleudlt), in northwest Florida. Annual soil...

Effect of replacing surface inlets with blind or gravel inlets on sediment and phosphorus subsurface drainage losses

USDA-ARS?s Scientific Manuscript database

Open surface inlets that connect to subsurface tile drainage systems provide a direct pathway for sediment, nutrients, and agrochemicals to surface waters. This study was conducted to determine whether modifying open inlets by burying them in gravel capped with 30 cm of sandy clay loam soil or in ve...

Soil bacterial and fungal community responses across a conservation reserve program chronosequence in Texas high plains region

USDA-ARS?s Scientific Manuscript database

We investigated changes in soil bacterial and fungal communities with increasing restoration time across a Conservation Reserve Program chronosequence (CRP) on fine sandy loam soils in the Texas high plains region. Soil samples (0-10cm) were collected in 2012 and 2014 from seven dryland croplands (0...

Dissipation of terbuthylazine, metolachlor and mesotrione in soils with contrasting texture

NASA Astrophysics Data System (ADS)

Carretta, Laura; Cardinali, Alessandra; Zanin, Giuseppe; Masin, Roberta

2017-04-01

Herbicides play an important role in the crops production, but their use may result in residues with undesirable effects on the environment. The determination of the herbicide dissipation rate in agricultural soil is an important issue for monitoring their environmental fate. As soil composition is one of the factors affecting herbicide persistence, this study aimed to evaluate the dissipation of three herbicides, terbuthylazine (TERB), metolachlor (METO) and mesotrione (MESO) in soils with contrasting texture. The field trial was conducted at the Padua University Experimental Farm (45.3° N, 12.0° E) in the Po Valley, north-east Italy in 2012. The persistence of three herbicides has been studied in three diverse soil textures (clay, sand and loam soil) at two different depths (0-5 and 5-15 cm). A randomized complete block design was used for this experiment with six plots (2 m × 2 m) for each of 3 treatments. TERB, METO and MESO were applied in May on maize as a formulated product (Lumax®) with hand-held field plot sprayer at a dose of 3.5 L/ha. Soil organic carbon content was the highest in clay texture (1.10%) followed by loam soil (0.67%) and sandy soil (0.24%). The soil was sampled with a soil auger before herbicides treatment, and soon after treatment soil samples were taken to assess initial concentration, then at increasing times from spraying to evaluate field dissipation kinetics (t50). The dissipation of the herbicides in the treated plots was followed for nearly 2 months after their application. The herbicides were analysed by liquid chromatography-mass spectrometry. The dissipation of TERB, METO and MESO could be described by a pseudo first order kinetics. Within the herbicides, TERB showed the highest t50, followed by METO and MESO. Considering the tested soil, the highest t50 value was found for clay soil texture for TERB and METO, whereas for MESO there was no difference among different soils. Significant differences were found within the 2 soil depths for TERB and MESO only in sandy soil, for METO only in loam soil. In detail, considering the average of both depths, TERB and METO degraded slowly in clay soil (22 days and 16 days respectively) followed by loam soil (14 days and 7 days) and sandy soil (12 days and 5 days). On the other hand, MESO did not show significant differences (ranging from about 4 days in clay soil to 5 days in loam soil). These results suggest that soil texture have a large influence on the dissipation of TERB and METO, whereas no influence was observed on MESO.

Fate and Transport of CL-20 and RDX in Unsaturated Laboratory Columns

NASA Astrophysics Data System (ADS)

Lemond, L. A.; Gamerdinger, A. P.; Szecsody, J. E.

2005-05-01

This research examines the fate and transport of two explosive compounds, Hexanitrohexaazaisowurtzitane (CL-20) and Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in unsaturated laboratory columns. The transport and fate of these compounds were studied under saturated and unsaturated conditions in three natural soils: coarse sand, sandy loam, and a silt loam. Unsaturated column experiments were conducted using an ultra-centrifugation method. Sorption and degradation parameters were determined by moment analysis and hydrodynamic parameters were assessed with a two-region flow model. Differences in these parameters were evaluated as a function of water content. The fate and transport of CL-20 is highly dependent on 1) the soil type and 2) the compound's residence time in the soil and 3) water content of the media. Sorption of CL-20 was rate-limited. CL-20 degradation in saturated columns produced a half-life of as much as 22hr, but in unsaturated columns the degradation rate increased considerably, producing a half life of as little as 2hr. The fate and transport of RDX are also affected by the soil type, but sorption appeared to be instantaneous. Degradation of RDX was negligible. Our results suggest that at very low water content immobile water regions may become (at least in effect) isolated water regions and significantly alter the retardation of the tracer. In the sandy loam, there was as much as a 20-fold over-prediction of the retardation factor in the unsaturated saturated columns when predicted by Kd values derived from saturated columns. In the coarse sand, Kd values derived from saturated columns over-predicted retardation in the unsaturated columns by as much as 30%. In the silt loam, retardation factors were over-predicted by as much as 80%. At very low water contents, predictions of tracer behavior become very difficult because of changes in the flow regime that cannot be directly accounted for.

Estimating of Soil Texture Using Landsat Imagery: a Case Study in Thatta Tehsil, Sindh

NASA Astrophysics Data System (ADS)

Khalil, Zahid

2016-07-01

Soil texture is considered as an important environment factor for agricultural growth. It is the most essential part for soil classification in large scale. Today the precise soil information in large scale is of great demand from various stakeholders including soil scientists, environmental managers, land use planners and traditional agricultural users. With the increasing demand of soil properties in fine scale spatial resolution made the traditional laboratory methods inadequate. In addition the costs of soil analysis with precision agriculture systems are more expensive than traditional methods. In this regard, the application of geo-spatial techniques can be used as an alternative for examining soil analysis. This study aims to examine the ability of Geo-spatial techniques in identifying the spatial patterns of soil attributes in fine scale. Around 28 samples of soil were collected from the different areas of Thatta Tehsil, Sindh, Pakistan for analyzing soil texture. An Ordinary Least Square (OLS) regression analysis was used to relate the reflectance values of Landsat8 OLI imagery with the soil variables. The analysis showed there was a significant relationship (p<0.05) of band 2 and 5 with silt% (R2 = 0.52), and band 4 and 6 with clay% (R2 =0.40). The equation derived from OLS analysis was then used for the whole study area for deriving soil attributes. The USDA textural classification triangle was implementing for the derivation of soil texture map in GIS environment. The outcome revealed that the 'sandy loam' was in great quantity followed by loam, sandy clay loam and clay loam. The outcome shows that the Geo-spatial techniques could be used efficiently for mapping soil texture of a larger area in fine scale. This technology helped in decreasing cost, time and increase detailed information by reducing field work to a considerable level.

Lysimeter study to investigate the effect of rainfall patterns on leaching of isoproturon.

PubMed

Beulke, Sabine; Brown, Colin D; Fryer, Christopher J; Walker, Allan

2002-01-01

The influence of five rainfall treatments on water and solute leaching through two contrasting soil types was investigated. Undisturbed lysimeters (diameter 0.25 m, length 0.5 m) from a sandy loam (Wick series) and a moderately structured clay loam (Hodnet series) received autumn applications of the radio-labelled pesticide isoproturon and bromide tracer. Target rainfall plus irrigation from the end of November 1997 to May 1998 ranged from drier to wetter than average (235 to 414 mm); monthly rainfall was varied according to a pre-selected pattern or kept constant (triplicate lysimeters per regime). Leachate was collected at intervals and concentrations of the solutes were determined. Total flow (0.27-0.94 pore volumes) and losses of bromide (3-80% of applied) increased with increasing inputs of water and were larger from the Wick sandy loam than from the Hodnet clay loam soil. Matrix flow appeared to be the main mechanism for transport of isoproturon through the Wick soil whereas there was a greater influence of preferential flow for the Hodnet lysimeters. The total leached load of isoproturon from the Wick lysimeters was 0.02-0.26% of that applied. There was no clear variation in transport processes between the rainfall treatments investigated for this soil and there was an approximately linear relationship (r2 = 0.81) between leached load and total flow. Losses of isoproturon from the Hodnet soil were 0.03-0.39% of applied and there was evidence of enhanced preferential flow in the driest and wettest treatments. Leaching of isoproturon was best described by an exponential relationship between load and total flow (r2 = 0.62). A 45% increase in flow between the two wettest treatments gave a 100% increase in leaching of isoproturon from the Wick soil. For the Hodnet lysimeters, a 35% increase in flow between the same treatments increased herbicide loss by 325%.

The utility of surface temperature measurements for the remote sensing of surface soil water status

NASA Technical Reports Server (NTRS)

Idso, S. B.; Jackson, R. D.; Reginato, R. J.; Schmugge, T. J.

1975-01-01

Experiments carried out on an Avondale loam soil indicated that the thermal inertia concept of soil water content detection is reasonably sound. The volumetric water contents of surface soil layers between 2 and 4 cm thick were found to be linear functions of the amplitude of the diurnal surface soil temperature wave for clear day-night periods. They were also found to be linear functions of the daily maximum value of the surface soil-air-temperature differential. Tests on three additional soils ranging from sandy loam to clay indicated that the relations determined for Avondale loam could not be accurately applied to these other soil types. When the moisture characteristic curves of each soil were used to transform water contents into pressure potentials, however, it was found that soil water pressure potential could be determined without prior knowledge of soil type, and thus its value as a potential soil water status survey tool was significantly enhanced.

Comparing seven planting tools for container-grown longleaf pine seedlings

Treesearch

James D. Haywood; Daniel J. Leduc; Shi-Jean S. Sung

2013-01-01

We compared seven tools for planting container-grown longleaf pine seedlings in fine sandy loam in Louisiana and in fine sand in Alabama. The tools were (1) JIM-GEM® KBC dibble bar, (2) JIM-GEM® OST Dibble Bar, (3) Terra Tech Styro 8 Dibble Stick, (4) container seedling tube dibble, (5) hoedad, (6) auger, and (7) shovel....

Physical and hydraulic properties of a sandy loam soil under zero, shallow and deep tillage practices

USDA-ARS?s Scientific Manuscript database

Over the centuries, tillage has been an important agronomic practice that has been used to mechanically alter soil properties and enhance the soil ecosystem for growth of crops. A 4-yr study investigated the impact of no-tillage (NT), shallow tillage at a 10-cm depth (ST), and deep tillage at a 30-c...

Comparisons of single-row and twin-row soybean production in the Mid South

USDA-ARS?s Scientific Manuscript database

A Maturity Group (MG) IV and MG V soybean [Glycine max (L.) Merr] cultivar were planted in single-rows and twin-rows on 102 cm beds at 20, 30, 40, and 50 seeds m-2 in a Beulah fine sandy loam (coarse-loamy, mixed thermic Typic Dystrochrepts) in 2008, 2009, 2010 and Sharkey clay (Vertic Haplaquept) i...

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...

Effect of urea application rate and water content on nitrous oxide emission from a sandy loam soil - a laboratory study

USDA-ARS?s Scientific Manuscript database

Agriculture is a major contributor to global anthropogenic nitrous oxide (N2O, a potent greenhouse gas) emission. Data from a pomegranate orchard indicate that N2O emission is highly variable with nitrogen application rates and irrigation methods. The aim of this study was to investigate the effect ...

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.

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.

Development of a low-cost soil moisture sensor for in-situ data collection by citizen scientists

NASA Astrophysics Data System (ADS)

Rajasekaran, E.; Jeyaram, R.; Lohrli, C.; Das, N.; Podest, E.; Hovhannesian, H.; Fairbanks, G.

2017-12-01

Soil moisture (SM) is identified as an Essential Climate Variable and it exerts a strong influence on agriculture, hydrology and land-atmosphere interaction. The aim of this project is to develop an affordable (low-cost), durable, and user-friendly, sensor and an associated mobile app to measure in-situ soil moisture by the citizen scientists or any K-12 students. The sensor essentially measures the electrical resistance between two metallic rods and the resistance is converted into SM based on soil specific calibration equations. The sensor is controlled by a micro-controller (Arduino) and a mobile app (available both for iOS and Android) reads the resistance from the micro-controller and converts it into SM for the soil type selected by the user. Extensive laboratory tests are currently being carried out to standardize the sensor and to calibrate the sensor for various soil types. The sensor will also be tested during field campaigns and recalibrated for field conditions. In addition to the development of the sensor and the mobile app, supporting documentation and videos are also being developed that show the step-by-step process of building the sensor from scratch and measurement protocols. Initial laboratory calibration and validation of the prototype suggested that the sensor is able to satisfactorily measure SM for sand, loam, sandy loam, sandy clay loam type of soils. The affordable and simple sensor will help citizen scientists to understand the dynamics of SM at their site and the in-situ data will further be utilized for validation of the satellite observations from the SMAP mission.

Incorporation of digestate selectively affects physical, chemical and biochemical properties along with CO2 emissions in two contrasting agricultural soils in the Mediterranean area.

NASA Astrophysics Data System (ADS)

Badagliacca, Giuseppe; Petrovičová, Beatrix; Zumbo, Antonino; Romeo, Maurizio; Gullì, Tommaso; Martire, Luigi; Monti, Michele; Gelsomino, Antonio

2017-04-01

Soil incorporation of digestate represents a common practice to dispose the solid residues from biogas producing plants. Although the digestate constitutes a residual biomass rich in partially decomposed organic matter and nutrients, whose content is often highly variable and unbalanced, its potential fertilizer value can vary considerably depending on the recipient soil properties. The aim of the work was to assess short-term changes in the fertility status of two contrasting agricultural soils in Southern Italy (Calabria), olive grove on a clay acid soil (Typic Hapludalfs) and citrus grove on a sandy loam slightly calcareous soil (Typic Xerofluvents), respectively located along the Tyrrhenian or the Ionian coast. An amount of 30 t ha-1 digestate was incorporated into the soil by ploughing. Unamended tilled soil was used as control. The following soil physical, chemical and biochemical variables were monitored during the experimental period: aggregate stability, pH, electrical conductivity, organic C, total N, Olsen-P, N-NH4+, N-NO3-, microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) and the mineralization quotient (qM). Moreover, in the olive grove soil CO2 emissions have been continuously measured at field scale for 5 months after digestate incorporation. Digestate application in both site exerted a significant positive effect on soil aggregate stability with a greater increase in clay than in sandy loam soil. Over the experimental period, digestate considerably affected the nutrient availability, namely Olsen-P, N-NH4+, N-NO3-, along with the electrical conductivity. The soil type increased significantly the soil N-NH4+ content, which was always higher in the olive than in citrus grove soil. N-NO3- content was markedly increased soon after the organic amendment, followed by a seasonal decline more evident in the sandy loam soil. Moreover, soil properties as CaCO3 content and the pH selectively affected the Olsen-P dynamics. No appreciable variation was recorded in total C and N pools. Interestingly, amendment with digestate altered the soil microbial community size in both soils as MBC and MBN were increased, although the response was more evident in the clay soil (olive) than in the sandy loam (citrus) one. The considerably higher qM observed in the clay soil suggests that the C mineralization was selectively stimulated in this soil. This finding was confirmed by the increase of CO2 emissions. As a whole our results show that digestate application selectively stimulated soil C dynamics and determined an unbalanced nutrient release, strongly depending on the soil physical-chemical properties. The use of digestate can therefore represent an interesting strategy for managing the soil fertility in Mediterranean agroecosystem soils, provided that digestate and recipient soil properties are carefully taken into account.

The impacts of pyrolysis temperature and feedstock type on biochar properties and the effects of biochar application on the properties of a sandy loam

NASA Astrophysics Data System (ADS)

Aston, Steve; Doerr, Stefan; Street-Perrott, Alayne

2013-04-01

The production of biochar and its application to soil has the potential to make a significant contribution to climate change mitigation whilst simultaneously improving soil fertility, crop yield and soil water-holding capacity. Biochar is produced from various biomass feedstock materials at varying pyrolysis temperatures, but relatively little is known about how these parameters affect the properties of the resultant biochars and their impact on the properties of the soils to which they are subsequently applied. Salix viminalis, M. giganteus and Picea sitchensis feedstocks were chipped then sieved to 2 - 5 mm, oven dried to constant weight, then pyrolyzed at 350, 500, 600 and 800° C in a nitrogen-purged tube furnace. Biochar yields were measured by weighing the mass of each sample before and after pyrolysis. Biochar hydrophobicity was assessed by using a goniometer to measure water-droplet contact-angles. Cation-exchange-capacity (CEC) was measured using the ammonium acetate method. Biochars were also produced in a rotary kiln from softwood pellets at 400, 500, 600 and 700° C then ground to 0.4 - 1 mm and applied to a sandy loam at a rate of 50 g kg-1. Bulk densities of these soil-biochar mixtures were measured on a tapped, dry, basis. The water-holding-capacity (WHC) of each mixture was measured gravimetrically following saturation and free-draining. The filter paper method was used to assess how pyrolysis temperature influences the effect of biochar application on matric suction. For all feedstocks, large decreases in biochar yield were observed between the pyrolysis temperatures of 350° C and 500° C. For Salix viminalis and M. giganteus feedstocks, subsequent reductions in the yield with increasing pyrolysis temperature were much lower. There were significant differences in hydrophobicity between biochars produced from different biomass and mean biochar hydrophobicity decreased with increasing pyrolysis temperature for all feedstocks. Results for CEC and WHC measurements will also be presented. With water contents of 0.04, 0.08 and 0.16 cm3 cm-3, the mean matric suctions of a sandy loam were higher when biochar was added. However, the differences were only statistically significant at a water content of 0.16 cm3 cm-3, where biochar produced at 500° C had the highest suction. Biochar additions always lowered the mean bulk density of a sandy loam, but there were significant differences in the extent to which biochars produced at different temperatures did this. Biochar yields and hydrophobicity vary according to feedstock type and decrease with increasing pyrolysis temperature. Application of biochar can significantly reduce bulk density but the extent of this effect varies according to the pyrolysis temperature at which the biochar is produced. Pyrolysis temperature can have a significant influence on how biochars affect soil suction. Acknowledgements: This study was funded by a UK Natural Environment Research Council (NERC) Doctoral Training Grant: NE/H525154/1.

The role of sediment compaction and groundwater withdrawal in local sea-level rise, Sandy Hook, New Jersey, USA

NASA Astrophysics Data System (ADS)

Johnson, Christopher S.; Miller, Kenneth G.; Browning, James V.; Kopp, Robert E.; Khan, Nicole S.; Fan, Ying; Stanford, Scott D.; Horton, Benjamin P.

2018-02-01

The rate of relative sea-level (RSL) rise at Sandy Hook, NJ (4.0 ± 0.5 mm/yr) was higher than The Battery, NY (3.0 ± 0.3 mm/yr) from 1900 to 2012 despite being separated by just 26 km. The difference cannot be explained by differential glacial isostatic adjustment (GIA; 1.4 ± 0.4 and 1.3 ± 0.4 mm/yr RSL rise, respectively) alone. We estimate the contribution of sediment compaction to subsidence at Sandy Hook using high-resolution grain size, percent organic matter, and porosity data from three upper Quaternary (≤13,350 cal yr) cores. The organic matter content (<2%) is too low to contribute to local subsidence. However, numerical modeling of the grain size-depth-age-porosity relationship indicates that compaction of deglacial silts likely reduced the column thickness by 10-20% over the past 13,350 cal yrs. While compaction rates were high immediately after the main silt deposition (13,350-13,150 cal yrs BP), rates decreased exponentially after deposition to an average 20th century rate of 0.16 mm/yr (90% Confidence Interval (C.I.), 0.06-0.32 mm/yr). The remaining ∼0.7 mm/yr (90% C.I. 0.3-1.2 mm/yr) difference in subsidence between Sandy Hook and The Battery is likely due to anthropogenic groundwater withdrawal. Historical data from Fort Hancock wells (2 km to the southeast of the Sandy Hook tide gauge) and previous regional work show that local and regional water extraction lowered the water levels in the aquifers underlying Sandy Hook. We suggest that the modern order of contribution to subsidence (highest to lowest) appears to be GIA, local/regional groundwater extraction, and compaction of thick Quaternary silts.

Phosphorus leaching from loamy sand and clay loam topsoils after application of pig slurry.

PubMed

Liu, Jian; Aronsson, Helena; Bergström, Lars; Sharpley, Andrew

2012-12-01

Appropriate management of animal waste is essential for guaranteeing good water quality. A laboratory leaching study with intact soil columns was performed to investigate the risk of phosphorus (P) leaching from a clay loam and a loamy sand. The columns (0.2 m deep) were irrigated before and after application of pig slurry on the surface or after incorporation, or application of mineral P, each at a rate of 30 kg P ha(-1). The two soils had different initial P contents (i.e. the ammonium lactate-extractable P was 65 and 142 mg kg(-1) for the clay loam and loamy sand, respectively), but had similar P sorption characteristics (P sorption index 3.0) and degree of P saturation (17-21%). Concentrations of dissolved reactive P (DRP) and total P (TP) before P application were significantly higher in leachate from the loamy sand (TP 0.21 mg L(-1)) than from the clay loam (TP 0.13 mg L(-1)), but only increased significantly after P application to the clay loam. The highest concentrations were found when slurry was surface-applied (DRP 1.77 mg L(-1)), while incorporation decreased the DRP concentration by 64% in the clay loam. Thus moderate slurry application to a sandy soil with low P saturation did not pose a major risk of P leaching. However, application of P increased the risk of P leaching from the clay loam, irrespective of application method and despite low P saturation. The results show the importance of considering soil texture and structure in addition to soil chemical characteristics in risk assessments of P leaching. Structured soils such as the clay loam used in this study are high risk soils and application of P to bare soil during wet periods, e.g. in autumn or spring, should be followed by incorporation or avoided completely.

A comparison of cation sampling in forest soils by tension and tension-free lysimeters

Treesearch

James H. Miller

1981-01-01

Field tests conducted in two soils with ceramic cup, ceramic plate, and tension-free lysimeters showed no concentration differences in collected cations (Ca, Mg, K, Na) between cups and plates, except for the hydrogen ion. Mean pH was 0.6 lower in cup collected samples for a sandy loam profile. Tension-free lysimeters of the design tested had persistent contamination...

Measurement and Modeling of Fugitive Dust from Off Road DoD Activities

DTIC Science & Technology

2017-12-08

each soil and vehicle type (see Table 2). Note, no tracked vehicles were run at YTC. CT is the curve track sampling location, CR is the curve ridge...Soil is SL = sandy loam. ...................... 116 Figure 35. Single-event Wind Erosion Evaluation Program (SWEEP) Run example results. ... 121...Figure 36. Single-event Wind Erosion Evaluation Program (SWEEP) Threshold Run example results screen

Whole-tree harvesting of pines with taproot attached

Treesearch

P. Koch

1974-01-01

The taproot of a 15- to 3O-yearold slash pine, with lateral roots pruned away, weighs about 20% as much as the bark-free merchantable stem to a four-inch top (dry-weight basis). Maximum taproot diameter, a few inches below ground level, is 1.5 to two times stem diameter at breast height. Length in sandy loam soils is commonly three to five feet.

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...

Optimal seeding depth of five forb species from the Great Basin

Treesearch

Jennifer K. Rawlins; Val J. Anderson; Robert Johnson; Thomas Krebs

2009-01-01

Use of forbs in revegetation projects in the Great Basin is limited due to high seed cost and insufficient understanding of their germination and establishment requirements. We tested the effects of seeding depth from 0 to 25.4 mm (1 in) on emergence and survival in clay and sandy loam soils of 5 ecologically important forbs. Significantly less emergence occurred of...

Effects of biochar on the emissions, soil distribution, and nematode control of 1,3-dichloropropene

USDA-ARS?s Scientific Manuscript database

Application of a rice husk-derived biochar to the surface of a sandy loam soil chamber reduced soil-air emissions of 1,3-dichloropropene (1,3-D) from 42% in a control (no biochar) to 8%. The difference in emissions was due to adsorption of 1,3-D onto the biochar, measured as 32.5%. The remaining 1,3...

Salty bark as a soil amendment

Treesearch

W.B. Bollen

1971-01-01

Bark from Douglas-fir logs floated in sea water contained 0.75 to 1.94 percent salt (NaCl). Leaching by natural and simulated rainfall and by soaking readily removed this salt. Bush bean and tomato plants were grown in the greenhouse on a sandy loam soil to which bark of three different proportions of salt was applied as a mulch and as an incorporation at the rate of...

76 FR 11086 - Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Carex lutea

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-01

... more in height. The yellowish green leaves are grass-like, with those of the culm mostly basal and up... lutea generally occurs on fine sandy loam, loamy fine sands, and fine sands with a pH of 5.5 to 7.2, and... (cutover muhly) is the most abundant grass in relatively undisturbed, specific locations of Carex lutea...

Core Versus Nuclear Gauge Methods of Determining Soil Bulk Density and Moisture Content

Treesearch

Jacqueline G. Steele; Jerry L. Koger; Albert C. Trouse; Donald L. Sirois

1983-01-01

Soil bulk and moisture content measurements were obtained using two nuclear gauge systems and those compared to those obtained from soil cores. The soils, a Hiwassee sandy loam, a Lakeland loamy sand, and a Loyd clay, were free of organic matter and uniform in mechanical composition. The regression equations developed for the nuclear guages for the first phase of the...

Influence of fertilizer placement on gaseous loss (CO2, CH4, N2O, and NH4) under different tillage management practices in a corn cropping system

USDA-ARS?s Scientific Manuscript database

Tillage and fertilizer application methods could alter plant yield and quality of corn production. Thus, a field experiment was conducted at the Sand Mountain Research Station located in the Appalachian Plateau region of Northeast Alabama on a Hartsells fine sandy loam to evaluate tillage (conventi...

Comparison of Five Woody Species for Reclamation of an Upper Coastal Plain Spoil Bank

Treesearch

J.W. McMinn; R.R. Roth; C.R. Berry; W.H. McNab

1980-01-01

Third-year survival and height are compared for autumn olive. European black alder, flowering crab apple, sawtooth oak, and Virginia pine on a sandy clay loam spoil bank in South Carolina. Flowering crab apple and sawtooth oak exhibited the best survival, while autumn olive and European black alder had greater height growth. Only European black alder failed to become...

Biochar increases plant-available water in a sandy loam soil under an aerobic rice crop system

NASA Astrophysics Data System (ADS)

de Melo Carvalho, M. T.; de Holanda Nunes Maia, A.; Madari, B. E.; Bastiaans, L.; van Oort, P. A. J.; Heinemann, A. B.; Soler da Silva, M. A.; Petter, F. A.; Marimon, B. H., Jr.; Meinke, H.

2014-09-01

The main objective of this study was to assess the impact of biochar rate (0, 8, 16 and 32 Mg ha-1) on the water retention capacity (WRC) of a sandy loam Dystric Plinthosol. The applied biochar was a by-product of slow pyrolysis (∼450 °C) of eucalyptus wood, milled to pass through a 2000 μm sieve that resulted in a material with an intrinsic porosity ≤10 μm and a specific surface area of ∼3.2 m2 g-1. The biochar was incorporated into the top 15 cm of the soil under an aerobic rice system. Our study focused on both the effects on WRC and rice yields 2 and 3 years after its application. Undisturbed soil samples were collected from 16 plots in two soil layers (5-10 and 15-20 cm). Soil water retention curves were modelled using a nonlinear mixed model which appropriately accounts for uncertainties inherent of spatial variability and repeated measurements taken within a specific soil sample. We found an increase in plant-available water in the upper soil layer proportional to the rate of biochar, with about 0.8% for each Mg ha-1 biochar amendment 2 and 3 years after its application. The impact of biochar on soil WRC was most likely related to an effect in overall porosity of the sandy loam soil, which was evident from an increase in saturated soil moisture and macro porosity with 0.5 and 1.6% for each Mg ha-1 of biochar applied, respectively. The increment in soil WRC did not translate into an increase in rice yield, essentially because in both seasons the amount of rainfall during the critical period for rice production exceeded 650 mm. The use of biochar as a soil amendment can be a worthy strategy to guarantee yield stability under short-term water-limited conditions. Our findings raise the importance of assessing the feasibility of very high application rates of biochar and the inclusion of a detailed analysis of its physical and chemical properties as part of future investigations.

Scratching technique for the study and analysis of soil surface abrasion mechanism

NASA Astrophysics Data System (ADS)

Ta, Wanquan

2007-11-01

Aeolian abrasion is the most fundamental and active surface process that takes place in arid and semi-arid environments. Its nature is a wear process for wind blown grains impinging on a soil or sediment surface, which causes particles and aggregates to fracture from the soil surface through a series of plastic and brittle cracking deformation such as cutting, ploughing and brittle fracturing. Using a Universal Micro-Tribometer (UMT), a scratching test was carried out on six soil surfaces (sandy soil, sand loam, silt loam, loam, silt clay loam, and silt clay). The results indicate that traces of normal and tangential force vs. time show a jagged curve, which can reflect the plastic deformation and brittle fracturing of aggregates and particles of various sizes fractured from the soil surfaces. The jagged curve peaks, and the area enclosed underneath, may represent the bonding forces and bonding energies of some aggregates and grains on the soil surface, respectively. Connecting the scratching test with an impact abrasion experiment furthermore demonstrates that soil surface abrasion rates are proportional to the square of speeds of impacting particles and to the 2.6 power of mean soil grain size, and inversely proportional to the 1.5 power of specific surface abrasive energy or to the 1.7 power of specific surface hardness.

Analyzing the impacts of three types of biochar on soil carbon fractions and physiochemical properties in a corn-soybean rotation.

PubMed

Sandhu, Saroop S; Ussiri, David A N; Kumar, Sandeep; Chintala, Rajesh; Papiernik, Sharon K; Malo, Douglas D; Schumacher, Thomas E

2017-10-01

Biochar is a solid material obtained when biomass is thermochemically converted in an oxygen-limited environment. In most previous studies, the impacts of biochar on soil properties and organic carbon (C) were investigated under controlled conditions, mainly laboratory incubation or greenhouse studies. This 2-year field study was conducted to evaluate the influence of biochar on selected soil physical and chemical properties and carbon and nitrogen fractions for two selected soil types (clay loam and a sandy loam soil) under a corn (Zea mays L.)-soybean (Glycine max L.) rotation. The three plant based biochar materials used for this study were corn stover (CS), ponderosa pine (Pinus ponderosa Lawson and C. Lawson) wood residue (PW), and switchgrass (Panicum virgatum L.) (SG). Data showed that CS and SG significantly increased the pH of acidic soil at the eroded landscape position but produced no significant change in soil pH at the depositional landscape position. The effects of biochar treatments on cold water extractable C (WSC) and nitrogen (WSN) fractions for the 0-7.5 cm depth were depended on biochar and soil type. Results suggested that alkaline biochars applied at 10 Mg ha -1 can increase the pH and WSC fraction of acidic sandy loam soil, but the 10 Mg ha -1 rate might be low to substantially improve physical properties and hot water extractable C and N fractions of soil. Application of higher rates of biochar and long-term monitoring is needed to quantify the benefits of biochar under field conditions on soils in different environmental conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Non-grazing and gophers lower bulk density and acidity in annual-plant soil

Treesearch

Raymond D. Ratliff; Stanley E. Westfall

1971-01-01

The effects of non-grazing on Ahwahnee coarse sandy loam were studied at the San Joaquin Experimental Range in central California. An exclosure, on which there had been no livestock grazing for 34 years, had a lower surface bulk density and lower acidity than an adjacent range that had been grazed. Bulk density averaged 1.08 gm./cc. on the ungrazed range, and 1.43 gm./...

Effect of Minesoil Compaction on Growth and Yield of KY-31 Tall Fescue and Sericea Lespedeza

Treesearch

Jerry T. Crews; Jerry T. Crews

1984-01-01

Kentucky 31 tall fescue and sericea lespedeza were sown on clay and loam minesoils that had been screened throu h a No. 10 sieve and compacted to densities of 1.6, 1.8, and 2.0 gfjcm3. Stands of sericea lespedeza were more difficult to establish than fescue on both minesoils and were more susceptible than fescue to increased levels of compaction. Dry matter yields...

Effects of shrub encroachment on soil organic carbon in global grasslands.

PubMed

Li, He; Shen, Haihua; Chen, Leiyi; Liu, Taoyu; Hu, Huifeng; Zhao, Xia; Zhou, Luhong; Zhang, Pujin; Fang, Jingyun

2016-07-08

This study aimed to evaluate the effect of shrub encroachment on soil organic carbon (SOC) content at broad scales and its controls. We conducted a meta-analysis using paired control data of shrub-encroached grassland (SEG) vs. non-SEG collected from 142 studies worldwide. SOC contents (0-50 cm) were altered by shrub encroachment, with changes ranging from -50% to + 300%, with an effect size of 0.15 (p < 0.01). The SOC contents increased in semi-arid and humid regions, and showed a greater rate of increase in grassland encroached by leguminous shrubs than by non-legumes. The SOC content decreased in silty and clay soils but increased in sand, sandy loam and sandy clay loam. The SOC content increment was significantly positively correlated with precipitation and temperature as well as with soil bulk density but significantly negatively correlated with soil total nitrogen. We conclude the main effects of shrub encroachment would be to increase topsoil organic carbon content. As structural equation model revealed, soils properties seem to be the primary factors responsible for the extent of the changes, coarse textured soils having a greater capacity than fine textured soils to increase the SOC content. This increased effect appears to be secondarily enhanced by climate and plant elements.

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.

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).

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.

[Ecological suitability regionalization for Gastrodia elata in Zhaotong based on Maxent and ArcGIS].

PubMed

Shi, Zi-Wei; Ma, Cong-Ji; Kang, Chuan-Zhi; Wang, Li; Zhang, Zhi-Hui; Chen, Jun-Fei; Zhang, Xiao-Bo; Liu, Da-Hui

2016-09-01

In this paper, the potential distribution information and ecological suitability regionalization for Gastrodia elata in Zhaotong were studied based on the climate, terrain, soil and vegetation factors analysis by Maxent and ArcGIS. The results showed that the highly potential distribution (suitability index>0.6) mainly located in Zhaotong, Yunnan province（Zhenxiong,Yiliang and Daguan county, with an area of 2 872 km²）, and Bijie, Guizhou province （Hezhang,Bijie,Weining county, 1 251 km²）. The AUC of ROC curve was above 0.99, indicating that the predictive results with the Maxent model were highly precise. The main ecological factors determining the potential distribution were the altitude, average rainfall in November, average rainfall in October, vegetation types, average rainfall in March, average rainfall in April,soil types,isothermal characteristic and average rainfall in June. The environmental variables in the highly potential areas were determined as altitude around 1 450-2 200 m,annual average temperature around 18.0-20.4 ℃,annual average precipitation around 900 mm,yellow soil or yellow brown soil,and acid sandy loam or slightly acidic sandy loam.The results will provide valuable references for plantation regionalization and the siting for imitation wild planting of G. elata in Zhaotong. Copyright© by the Chinese Pharmaceutical Association.

Determination of phenanthrene bioavailability by using a self-dying reporter bacterium: test with model solids and soil.

PubMed

Shin, Doyun; Nam, Kyoungphile

2012-02-20

The present study was conducted to investigate the performance and feasibility of a self-dying reporter bacterium to visualize and quantify phenanthrene bioavailability in soil. The self-dying reporter bacterium was designed to die on the initiation of phenanthrene biodegradation. The viability of the reporter bacterium was determined by a fluorescence live/dead cell staining method and visualized by confocal laser scanning microscopic observation. Phenanthrene was spiked into four types of model solids and a sandy loam. The bioavailability of phenanthrene to the reporter bacterium was remarkably declined with the hydrophobicity of the model solids: essentially no phenanthrene was biodegraded in the presence of 9-nm pores and about 35.8% of initial phenanthrene was biodegraded without pores. Decrease in bioavailability was not evident in the nonporous hydrophilic bead, but a small decrease was observed in the porous hydrophilic bead at 1000 mg/kg of phenanthrene. The fluorescence intensity was commensurate with the extent of phenanthrene biodegradation by the reporter bacterium at the concentration range from 50 to 500 mg/kg. Such a quantitative relationship was also confirmed with a sandy loam spiked up to 1000 mg/kg of phenanthrene. This reporter bacterium may be a useful means to determine phenanthrene bioavailability in soil. Copyright © 2011 Elsevier B.V. All rights reserved.

Electrochemical characterization of corrosion in materials of grounding systems, simulating conditions of synthetic soils with characteristics of local soils

NASA Astrophysics Data System (ADS)

Salas, Y.; Guerrero, L.; Vera-Monroy, S. P.; Blanco, J.; Jimenez, C.

2017-12-01

The integrity of structures buried in earthing becomes relevant when analysing maintenance and replacement costs of these systems, as the deterioration is mainly due to two factors, namely: the failures caused in the electrical systems, which are due to the system. Failure in earthing due to corrosion at the interface cause an alteration in the structure of the component material and generates an undesirable resistivity that cause malfunction in this type of protection systems. Two local soils were chosen that were categorized as sandy loam and clay loam type, whose chemical characteristics were simulated by means of an electrolyte corresponding to the amount of ions present determined by a soil characterization based on the CICE (effective cation exchange coefficient), which allows us to deduce the percentage of chloride and sulphate ions present for the different levels established in the experimental matrix. The interaction of these soils with grounding electrodes is a complex problem involving many factors to consider. In this study, the rates and corrosion currents of the different soils on two types of electrodes, one copper and the other AISI 304 stainless steel, were approximated by electrochemical techniques such as potentiodynamic curves and electrochemical impedance spectra. Considerably higher speeds were determined for copper-type electrodes when compared to those based on steel. However, from the Nyquist diagrams, it was noted that copper electrodes have better electrical performance than steel ones. The soil with the highest ionic activity turned out to be the sandy loam. The clay loam soil presents a tendency to water retention and this may be the reason for the different behaviour with respect to ionic mobility. The diffusion control in the steel seems to alter the ionic mobility because its corrosion rates proved to be very similar regardless of the type of soil chemistry. In general, corrosion rates fell since tenths of a millimetre every year to the hundredths of a millimetre in the case of the steel-based electrode, which are relatively small corrosion rates.

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

Use of 15N labeled Urea to Study Nitrogen Use Efficiencies in a Forage Corn-Oat Rotation Grown on Clay and Sandy Clay Loam Soils of Mexico

USDA-ARS?s Scientific Manuscript database

Nitrogen (N) is applied in large amounts to sustain high forage yield and quality to feed a dairy cattle population surpassing 440,000 heads in Comarca Lagunera, Mexico (25° 32´ N, 103° 14´W and 1150 masl). Traditional farm practices across this region overaplly organic (manure) and fertilizer N. We...

Effects of tractor loads and tyre pressures on soil compaction in Tunisia under different moisture conditions

NASA Astrophysics Data System (ADS)

Khemis, Chiheb; Abrougui, Khaoula; Ren, Lidong; Mutuku, Eunice Ann; Chehaibi, Sayed; Cornelis, Wim

2017-04-01

Vegetables in Tunisia demand frequent tractor traffic for soil tillage, cultural operations and phytosanitary treatment, resulting in soil compaction. This study evaluates the effects of four levels of compaction by using different loads and tyre pressures of tractors, i.e., load 1 (C1) = 1460 kg, load 2 (C2) = 3100 kg, tyre pressure 1 (C3) = 800 kg cm-2, tyre pressure 2 (C4) = 1500 kg cm-2 on the hydraulic and physical properties of a sandy loam (10% clay, 20% silt, 68% sand) under three natural moisture conditions H0, H1 (15 days later), H2 (30 days later). At H0 average water content between 0 and 30 cm depth varied from 0.04 to 0.06 kg kg-1, at H1 between 0.13 and 0.07 kg kg-1, and at H2 between 0.10 and 0.09 kg kg-1. Each test run was limited to one pass. Undisturbed soil cores were collected in the topsoil (0-10 cm), at 10-20 cm and in the subsoil (20-30 cm) below the trace of the wheel at sites in the Higher Institute of Agronomy of Chott Mariam, Sousse, Tunisia. Soil compaction level was determined by penetration resistance using a penetrologger. Porosity, bulk density and permeability were then determined to evaluate the impact of the four load/tyre pressure combinations at the three moisture conditions on soil compaction. Prior to the experiment (C0), bulk density was 1.4 Mg m-3. After the tractor pass, the highest degree of compaction was observed with tractor load C2 and tyre pressure C4 which significantly changed soil bulk density resulting in values of up to 1.71 Mg m-3 in the topsoil and compacted subsoil under H2, which is significantly above the critical value of 1.6 Mg m-3 for soils with clay content below 17.5%. The high degree of compaction significantly affected penetration resistance and porosity of both topsoil and subsoil layers accordingly. Permeability was significantly reduced as a result of the induced compaction. The results demonstrate that different degrees of soil compaction under different moisture levels could greatly influence hydraulic and physical properties in different ways. Even under relatively low water contents, i.e., below or near field capacity, substantial top and subsoil compaction was induced after one tractor pass.

Trace gas emissions following deposition of excreta by grazing dairy cows in eastern Canada

NASA Astrophysics Data System (ADS)

Rochette, P.; Pelster, D. E.; Chantigny, M. H.; Angers, D. A.; Liang, C.; Belanger, G.; Ziadi, N.; Charbonneau, E.; Pellerin, D.

2012-04-01

The N2O emission factor proposed for cattle excreta N by the Tier I IPCC methodology (EF3) is 2% (IPCC, 2006). While N2O emissions from excreta deposited by grazing animals have been reported in several publications, relatively few estimated EF3 values because measurements did not cover the entire year. This study measured N2O and CH4 flux and crop dry matter (DM) yield over two years (2009 to 2011) from a clay and a sandy loam soil cultivated with Timothy grass (Phleum pratense L.). A split-plot design was used on each soil type, with different application dates (either spring, summer or autumn application) as main plots and treatment (U-50: urine 50 g N m-2, U-100: urine 100 g N m-2, dung: 60 g N m-2, and control) as the sub-plots. Regardless of application time, annual DM yield increased in all treated plots when compared to the control. Also, DM yields were generally greater when urine as opposed to dung was applied suggesting greater N-availability from the urine application. The CH4 flux from the dung plots increased for only the first two weeks after treatment while the flux from the urine plots was similar to the control plots. Cumulative N2O emissions on the U-50 and U-100 plots increased linearly with urine N rate on both soils, resulting in nearly identical mean emission factors for both urine rates. The emission factor for the urine was three times greater on the clay (1.02% of applied N on both rates) than on the sandy loam soil (0.26% (U100) and 0.31% (U50) of applied N). Cumulative N2O emissions from dung plots also differed between soil types; however the impact of soil type on N2O emissions was opposite to that of urine, with greater losses from the sandy loam (0.15%) compared with the clay soil (0.07%). These results suggest that estimates of soil N2O emissions by grazing cattle in Eastern Canada obtained using the IPCC default methodology are overestimates of actual values and that these estimates for should include a stratification according to soil type.

Precipitation pulse use by an invasive woody legume: the role of soil texture and pulse size.

PubMed

Fravolini, Alessandra; Hultine, Kevin R; Brugnoli, Enrico; Gazal, Rico; English, Nathan B; Williams, David G

2005-08-01

Plant metabolic activity in arid and semi-arid environments is largely tied to episodic precipitation events or "pulses". The ability of plants to take up and utilize rain pulses during the growing season in these water-limited ecosystems is determined in part by pulse timing, intensity and amount, and by hydrological properties of the soil that translate precipitation into plant-available soil moisture. We assessed the sensitivity of an invasive woody plant, velvet mesquite (Prosopis velutina Woot.), to large (35 mm) and small (10 mm) isotopically labeled irrigation pulses on two contrasting soil textures (sandy-loam vs. loamy-clay) in semi-desert grassland in southeastern Arizona, USA. Predawn leaf water potential (psi(pd)), the isotopic abundance of deuterium in stem water (deltaD), the abundance of 13C in soluble leaf sugar (delta13C), and percent volumetric soil water content (theta(v)) were measured prior to irrigation and repeatedly for 2 weeks following irrigation. Plant water potential and the percent of pulse water present in the stem xylem indicated that although mesquite trees on both coarse- and fine-textured soils quickly responded to the large irrigation pulse, the magnitude and duration of this response substantially differed between soil textures. After reaching a maximum 4 days after the irrigation, the fraction of pulse water in stem xylem decreased more rapidly on the loamy-clay soil than the sandy-loam soil. Similarly, on both soil textures mesquite significantly responded to the 10-mm pulse. However, the magnitude of this response was substantially greater for mesquite on the sandy-loam soil compared to loamy-clay soil. The relationship between psi(pd) and delta13C of leaf-soluble carbohydrates over the pulse period did not differ between plants at the two sites, indicating that differences in photosynthetic response of mesquite trees to the moisture pulses was a function of soil water availability within the rooting zone rather than differences in plant biochemical or physiological constraints. Patterns of resource acquisition by mesquite during the dynamic wetting-drying cycle following rainfall pulses is controlled by a complex interaction between pulse size and soil hydraulic properties. A better understanding of how this interaction affects plant water availability and photosynthetic response is needed to predict how grassland structure and function will respond to climate change.

Assessing the value of multi-receiver low-frequency electromagnetic-induction (EMI) measurement for assessing variation in soil moisture content in field experiments with winter wheat (Triticum aestivum)

NASA Astrophysics Data System (ADS)

Shanahan, Peter; Binley, Andrew; Dodd, Ian; Whalley, Richard; Watts, Chris; Ashton, Rhys; Ober, Eric

2014-05-01

In large plant breeding field trials with multiple genotypes, measuring soil water status (an indicator of crop water uptake) by conventional techniques (e.g. core extraction and penetration resistance) is limited by the cost and effort needed to achieve sufficient replication to apply robust statistical analysis. Geophysical methods may provide a more cost-effective means of more assessing valuable information about soil water status for such studies. We present here results from a field experiment using geophysical techniques for remote mapping of soil water content on sandy loam and silt loam soils in spring/summer 2013 in the UK. The aim of the study was to assess electromagnetic-induction (EMI) conductivity measurements for sensitivity to variations in shallow soil electrical properties and the spatial and temporal mapping of soil water. The CMD Mini-Explorer (GF Instruments) operates with three receiver coils at fixed distances from a transmitter coil (0.32 m, 0.71 m, 1.2 m). Measurement of magnetic field quadrature in horizontal coplanar (HC) and vertical coplanar (VC) of the three receiver coils provides six depths of investigation for the given coil spacing cumulative sensitivities. At the two field sites the instrument was applied to measuring apparent electrical conductivity (ECa) below 7.0 x 1.8 m plots consisting of 23 rain fed winter wheat cultivars and bare soil fallow control plots. These plots were sown in March 2013 and organised into a randomised block design. Electrical resistivity tomography (ERT) surveys along 15 m transects were also conducted at the two sites in order to compare EMI measured ECa. Our results show that progressive soil drying at both sites due to crop uptake significantly decreased (p<0.05) soil ECa. The difference in soil ECa as a result of water uptake between cultivars was found to be significant (p<0.05) from one of the coil configurations (coil spacing 1.8m in HC mode), and only at the silty loam site (no significant difference was found in data from the sandy loam site). The difference in soil ECa over time was expected owing to crop root development and low rainfall during the growing season. It was expected that soil ECa between certain cultivars in the June and July would differ over all investigation depths at both sites. It was not possible in this study to produce calibrations for EMI measured ECa from the ERT data. Our study confirms the suitability of multi-core EMI devices for efficient and repeatable measurements of soil ECa in trials of winter wheat cultivars, providing data on soil ECa with minimal user requirements and instrument error. Differences in soil ECa as a result of crop water uptake was, however, not fully conclusive, since water extraction by the different cultivars is difficult to detect with the instrument, especially on sandy textured soils. The full-depth of investigation (1.8 m) of the instrument used on silt loam soil textures can provide qualitative data on crop performance. Over time, with gradual soil drying, the instrument detected reductions in ECa at all depths of investigation in both sandy and silt textured soils. Further analysis will be done using profiles of electrical conductivity determined from inversions of measured ECa values. ERT data calibration of EMI measured ECa was not possible due to lower than expected variation in ECa measured along the 15 m transect over the field season. This has meant a change in the methodology by having transects crossing soil with greater vertical variation in ECa (determined from field EMI surveys) and surface conditions (e.g. bare and cropped soil).

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).

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.

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 the priming effect caused by plant litter. Reference: Frøseth RB, Bleken MA(2015) Effect of low temperature and soil type on the decomposition rate of soil organic carbon and clover leaves, and related priming effect. Soil Biology and Biochemistry 80:156-166.

Improved retention of imidacloprid (Confidor) in soils by adding vermicompost from spent grape marc.

PubMed

Fernández-Bayo, Jesús D; Nogales, Rogelio; Romero, Esperanza

2007-05-25

Batch sorption experiments of the insecticide imidacloprid by ten widely different Spanish soils were carried out. The sorption was studied for the active ingredient and its registered formulation Confidor. The temperature effect was studied at 15 degrees C and 25 degrees C. The addition of a vermicompost from spent grape marc (natural and ground), containing 344 g kg(-1) organic carbon, on the sorption of imidacloprid by two selected soils, a sandy loam and a silty clay loam, having organic carbon content of 3.6 g kg(-1) and 9.3 g kg(-1), respectively, was evaluated. Prior to the addition of this vermicompost, desorption isotherms with both selected soils, were also performed. The apparent hysteresis index (AHI) parameter was used to quantify sorption-desorption hysteresis. Sorption coefficients, K(d) and K(f), for the active ingredient and Confidor(R) in the different soils were similar. Sorption decreased with increasing temperature, this fact has special interest in greenhouse systems. A significant correlation (R(2)=0.965; P<0.01) between K(f) values and the organic carbon (OC) content was found, but some soils showed higher sorption coefficients than that expected from their OC values. The normalized sorption coefficients with the soil organic carbon content (K(oc)) were dispersed and low, implying that other characteristics of soils could contribute to the retention capacity as well. The spent grape marc vermicompost was an effective sorbent of this insecticide (K(f)=149). The sorption of imidacloprid increased significantly in soils amended with this vermicompost. The most pronounced effect was found in the sandy loam soil with low OC content, where the addition of 5% and 10% of vermicompost increased K(f) values by 8- and 15-fold, respectively. Soil desorption of imidacloprid was slower for the soil with the higher OC and clay content.

Probabilistic risk assessment of nitrate groundwater contamination from greenhouses in Albenga plain (Liguria, Italy) using lysimeters.

PubMed

Paladino, Ombretta; Seyedsalehi, Mahdi; Massabò, Marco

2018-09-01

The use of fertilizers in greenhouse-grown crops can pose a threat to groundwater quality and, consequently, to human beings and subterranean ecosystem, where intensive farming produces pollutants leaching. Albenga plain (Liguria, Italy) is an alluvial area of about 45km 2 historically devoted to farming. Recently the crops have evolved to greenhouses horticulture and floriculture production. In the area high levels of nitrates in groundwater have been detected. Lysimeters with three types of reconstituted soils (loamy sand, sandy clay loam and sandy loam) collected from different areas of Albenga plain were used in this study to evaluate the leaching loss of nitrate (NO 3 - ) over a period of 12weeks. Leaf lettuce (Lactuca sativa L.) was selected as a representative green-grown crop. Each of the soil samples was treated with a slow release fertilizer, simulating the real fertilizing strategy of the tillage. In order to estimate the potential risk for aquifers as well as for organisms exposed via pore water, nitrate concentrations in groundwater were evaluated by applying a simplified attenuation model to the experimental data. Results were refined and extended from comparison of single effects and exposure values (Tier I level) up to the evaluation of probabilistic distributions of exposure and related effects (Tier II, III IV levels). HHRA suggested HI >1 and about 20% probability of exceeding RfD for all the greenhouses, regardless of the soil. ERA suggested HQ>100 for all the greenhouses; 93% probability of PNEC exceedance for greenhouses containing sand clay loam. The probability of exceeding LC50 for 5% of the species was about 40% and the probability corresponding to DBQ of DEC/EC50>0.001 was >90% for all the greenhouses. The significantly high risk, related to the detected nitrate leaching loss, can be attributed to excessive and inappropriate fertigation strategies. Copyright © 2018 Elsevier B.V. All rights reserved.

Impact of spreading olive mill waste water on agricultural soils for leaching of metal micronutrients and cations.

PubMed

Aharonov-Nadborny, R; Tsechansky, L; Raviv, M; Graber, E R

2017-07-01

Olive mill waste water (OMWW) is an acidic (pH 4-5), saline (EC ∼ 5-10 mS cm -1 ), blackish-red aqueous byproduct of the three phase olive oil production process, with a high chemical oxygen demand (COD) of up to 220,000 mg L -1 . OMWW is conventionally disposed of by uncontrolled dumping into the environment or by semi-controlled spreading on agricultural soils. It was hypothesized that spreading such liquids on agricultural soils could result in the release and mobilization of indigenous soil metals. The effect of OMWW spreading on leaching of metal cations (Na, K, Mg, Mn, Fe, Cu, Zn) was tested in four non-contaminated agricultural soils having different textures (sand, clay loam, clay, and loam) and chemical properties. While the OMWW contributed metals to the soil solution, it also mobilized indigenous soil metals as a function of soil clay content, cation exchange capacity (CEC), and soil pH-buffer capacity. Leaching of soil-originated metals from the sandy soil was substantially greater than from the loam and clay soils, while the clay loam was enriched with metals derived from the OMWW. These trends were attributed to cation exchange and organic-metal complex formation. The organic matter fraction of OMWW forms complexes with metal cations; these complexes may be mobile or precipitate, depending on the soil chemical and physical environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spatial variability of soil salinity in coastal saline soil at different scales in the Yellow River Delta, China.

PubMed

Wang, Zhuoran; Zhao, Gengxing; Gao, Mingxiu; Chang, Chunyan

2017-02-01

The objectives of this study were to explore the spatial variability of soil salinity in coastal saline soil at macro, meso and micro scales in the Yellow River delta, China. Soil electrical conductivities (ECs) were measured at 0-15, 15-30, 30-45 and 45-60 cm soil depths at 49 sampling sites during November 9 to 11, 2013. Soil salinity was converted from soil ECs based on laboratory analyses. Our results indicated that at the macro scale, soil salinity was high with strong variability in each soil layer, and the content increased and the variability weakened with increasing soil depth. From east to west in the region, the farther away from the sea, the lower the soil salinity was. The degrees of soil salinization in three deeper soil layers are 1.14, 1.24 and 1.40 times higher than that in the surface soil. At the meso scale, the sequence of soil salinity in different topographies, soil texture and vegetation decreased, respectively, as follows: depression >flatland >hillock >batture; sandy loam >light loam >medium loam >heavy loam >clay; bare land >suaeda salsa >reed >cogongrass >cotton >paddy >winter wheat. At the micro scale, soil salinity changed with elevation in natural micro-topography and with anthropogenic activities in cultivated land. As the study area narrowed down to different scales, the spatial variability of soil salinity weakened gradually in cultivated land and salt wasteland except the bare land.

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

DTIC Science & Technology

2005-04-01

oat. The authors reported seed germination EC5 0 values of 19 mg kg-1 for lettuce and > 375 mg kg-1 for oat. 11 Few studies investigated the toxicity...to evapo-transpiration. Plant toxicity tests were performed in a temperature and light controlled growth chamber. Plants were incubated in the dark for... seeds . Kandy corn Canada No. 1 and Japanese millet seeds gave satisfactory germination with seedling emergence of 100% and 85%, respectively. Two

Vapor Intrusion from Entrapped NAPL Sources and Groundwater Plumes: Process Understanding and Improved Modeling Tools for Pathway Assessment

DTIC Science & Technology

2014-07-01

into a building ....149 Figure 5.52: Effect of infiltration at 1 mm/hr for 24 hours on vapor signals in sandy clay loam scenario...shown above, there will also likely be large diameter sanitary sewers running the length of each street. Each house on the street will have a sewer...permeability, a discontinuous clay layer system, and a system with scattered obstacles (e.g. utilities). The layered systems indicated that the sequence of

Effect of Pellet Size of Defoliation and Estimated Kill of Small Stems Treated with Hexazinone

Treesearch

J.L. Michael

1981-01-01

Hexazinone [3-cyclohexyl-6-(dimethylamino)-1-methyl-1,2,5-triaine-2,4,(1H,2H)-dione] was tested in the 2, 1, and 0.5 cc size uellet (10% ai) against very small stems [average height, 1.97m; average ground line diameter (GLD), 2 cm] of water oak, Quercus nigra L., at 1.12 and 2.24 kg/ha on a sandy loam soil. First year defoliation of water oak by...

Determination of Selenium Toxicity for Survival and Reproduction of Enchytraeid Worms in a Sandy Loam Soil

DTIC Science & Technology

2016-07-01

ecotoxicological benchmarks for developing the ecological soil screening levels (Eco-SSLs) for risk assessments of contaminated soils. For the present study, we...or manufacturers ’ names in this report does not constitute an official endorsement of any commercial products. This report may not be cited for...Disposal of Se in commercial products and waste can also contribute to Se contaminant levels in soil. Se has been found in at least 508 of the 1623

Toxicity of a New Polynitramine Energetic Material, CL-20, to the Enchytraeid Worm, Enchytraeus Crypticus, in a Sandy Loam Soil

DTIC Science & Technology

2006-08-01

transformation, and other fate processes that commonly occur at contaminated sites ( Kaplan , 1992; Gorontzy et al., 1994; Preuf and Rieger, 1995; Daun et al...CL-20) by denitrifying Pseudomonas sp. strain FA1 . Appl. Environ. Microbiol. 69, 5216-5221. Bhushan, B., Halasz, A., Hawari, J., 2004a...contamination at military firing ranges. Technical Report ERDC TR-01-5. USACE Engineer Research and Development Center, Vicksburg, MS. 26 Kaplan , D.L

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

NASA Astrophysics Data System (ADS)

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

2014-12-01

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

Freeze-Thaw Cycles Effects on Soil Compaction in a Clay Loam

NASA Astrophysics Data System (ADS)

Jabro, J.; Evans, R.; Iversen, W.

2012-04-01

Inappropriate soil management practices and heavier farm machinery and equipment have led to an increase in soil compaction in the last two decades prompting increased global concern regarding the impact of soil compaction on crop production and soil quality in modern mechanized agriculture. A 3-yr comprehensive study was established to evaluate the dynamic of freeze-thaw cycles on soil compaction in a clay loam soil. Plots of frozen soils were compared with plots where soils were prevented from freezing with electrically heated blankets commonly used on concrete. Results showed that frequent freeze-thaw cycles over the winter alleviated a majority of soil compaction at the 0 - 20 cm depth. Soil penetration resistance in compacted soils was reduced by 73 and 68% over the winter at the 0 - 10 and 10 - 20 cm depths, respectively, due to dynamic effects of freeze-thaw cycles on soil structure and particles configuration. In unfrozen compacted soils, the penetration resistance was also reduced by 50 and 60% over winter at the 0 - 10 and 10 - 20 cm depths, respectively, due to the biology of soil, microbial activity, and disruptive effects of shrink-swell cycles. These results have demonstrated of how repeated freeze-thaw cycles can alleviate soil compaction, alter soil physical quality and create optimal soil conditions required for profitable growth of agricultural crops. The results from this study will save growers considerable time, money and energy currently required to alleviate soil compaction using other methods such as sub-soiling and deep tillage. We believe that Mother Nature provides ways to reverse soil compaction and improve soil structure and aggregation through the dynamic of freeze-thaw cycles that soils in Montana and other parts of the country go through each year. We concluded that the Mother Nature is the most effective and cheapest way to alleviate soil compaction.

Investigating the Influence of Clay Mineralogy on Stream Bank Erodibility

NASA Astrophysics Data System (ADS)

Ambers, R. K.; Stine, M. B.

2005-12-01

Soil scientists concerned with erosion of agricultural fields and geotechnical engineers concerned with the mechanical behavior of soils under different conditions have both examined the role of clay mineralogy in controlling soil/sediment properties. Fluvial geomorphologists studying stream channel erosion and stability have focused more on the effects of particle-size distribution, vegetation and rooting. The clay mineralogy of bed and bank sediment has the potential to influence cohesiveness and erodibility, however. The goal of this study is to determine the influence of clay mineralogy on the erodibility of natural stream bank sediment, utilizing techniques drawn from pedology and soil mechanics. Bank samples were collected from eleven sites in small watersheds in central and western Virginia. To obtain sediment containing a range of different clay minerals, watersheds with different types of bedrock were chosen for sampling. Rock types included mafic to felsic metamorphic and igneous rocks, shale, sandstone, and limestone. Where stream bank materials were clearly stratified, different layers were sampled separately. X-ray diffraction of the clay-fraction of the sediment indicates the presence of kaolinite, illite, vermiculite, and mixed-layer clay minerals in various abundances in the different samples. Clay content is 9-46%, as determined by the hydrometer method, and textures range from silty clay and silt loam to clay loam and sandy loam. Organic mater contents range from 1-5% by the loss-on-ignition method. Bulk density of intact sediment samples averages 1.5 g/cc. Liquid limits range from 23-41 with one sample having a value of 65; plasticity indices range from 15-22. While these tests predict that the samples would show a range of mechanical behaviors, the channel morphology at the sampling sites was not strikingly different, all having steep cut banks eroded primarily by scour with no evidence of mass movement and most having a width/depth ratio around 4.5. The ASTM pinhole test for identifying dispersive clay soils is being adapted to measure erodibility of intact and remolded sediment samples in the laboratory to look for more subtle differences in behavior under erosive conditions. Factors such as the extent and method of sample compaction are being taken into account in order to standardize the method.

Relationship of grapevine yield and growth to nematode densities.

PubMed

Ferris, H; McKenry, M V

1975-07-01

Yield, growth, and vigor of individual grape vines were correlated with nematode population densities in a series of California vineyards. In a Hanford sandy loam soil, Xiphinema americanum densities showed negative correlations with yield, growth, and vigor of vines. When vines were categorized according to vigor, X. americanurn densities had little relationship to yield of high-vigor vines, but were negatively correlated with yield of low-vigor vines. Densities of Paratylenchus harnatus were positively correlated with yield, growth, and vigor of vines. Correlations between Meloidogyne spp. densities and vine performance were variable, even when the vines were separated according to soil type and plant vigor. Densities of Meloidogyne spp. populations were generally higher on coarser-textured, sandy soils and the vines were less vigorous there. Densities of P. hamatus were greater in fine-textured soils.

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.

Remote sensing of the surface emissivity at 9 microns over the globe. [over desert regions with IR Interferometer Spectrometer data

NASA Technical Reports Server (NTRS)

Prabhakara, C.; Dalu, G.

1976-01-01

The infrared spectral measurements made by the Nimbus 4 infrared interferometer spectrometer (Iris) for a period of about 10 months are used to study the surface emissivity properties over the globe. It is found that the surface emissivity at 9 microns, as measured by Iris with a circular field of view of about 100-km diameter, is significantly less than unity over arid and semiarid areas. The spectral features in the 8-12-micron window observed over these lands reveal emissivity characteristics essentially due to quartz (SiO2). It is found that these emissivity features are significantly weakened by the presence of clay, clay horizons, or pedogenic horizons in the soil. Low emissivity is observed over sandy or sandy loam areas (psamments) with no clay or pedogenic horizons.

Determining fate and transport parameters for nitroglycerine, 2,4-dinitrotoluine, and nitroguanidine in soils

NASA Astrophysics Data System (ADS)

Gosch, D. L.; Dontsova, K.; Chorover, J.; Ferré, T.; Taylor, S.

2010-12-01

During military operations, a small fraction of propellant mass is not consumed during firing and is deposited onto the ground surface (Jenkins et al., 2006). Soluble propellant constituents can be released from particulate residues into the environment. Propellant constituents of interest for this study are nitroglycerine (NG), 2,4-dinitrotoluine (2,4-DNT), 2,6-dinitrotoluine (2,6-DNT), and nitroguanidine (NQ). The goal of this work is to determine fate and transport parameters for these constituents in three soils that represent a range of geographic locations and soil properties. This supports a companion study that looks at dissolution of NG, 2,4-DNT, 2,6-DNT, and NQ from fired and unfired solid propellant formulations and their transport in soils. The three soils selected for the study are Catlin silt loam (fine-silty, mixed, mesic, superactive Oxyaquic Argiudoll), Plymouth sandy loam (mesic, coated Typic Quartzipsamment), and Sassafras loam (fine loamy, siliceous, mesic Typic Hapudult). Two of these soils, Plymouth sandy loam and Sassafras loam, were collected on military installations. Linear adsorption coefficients and transformation rates of propellant constituents were determined in batch kinetic experiments. Soils were mixed with propellant constituent solutions (2 mg L-1) at 4:1 solution/soil mass ratio and equilibrated for 0, 1, 2, 6, 12, 24, 48, and 120 hr at which time samples were centrifuged and supernatant solutions were analyzed for target compounds by high performance liquid chromatography (HPLC) using U.S. EPA Method 8330b for NG, 2,4-DNT, and 2,6-DNT, and Walsh (1989) method for NQ. Adsorption and transformation of propellant constituents were determined from the decrease in solution concentration of these compounds. It was determined that all studied compounds were subjected to sorption by the solid phase and degradation. Catlin soil, with finer texture and high organic matter content, influenced solution concentration of NG, 2,4-DNT, 2,6-DNT, and NQ to the greatest extent. Estimated fate and transport parameters will support ongoing release and column transport studies and will allow environmental managers on military installations to better estimate potential for propellant constituent transport off-site. Jenkins, T.F., A.D. Hewitt, C.L. Grant, S. Thiboutot, G. Ampleman, M.E. Walsh, T.A. Ranney, C.A. Ramsey, A.J. Palazzo, and J.C. Pennington. 2006. Identity and distribution of residues of energetic compounds at army live-fire training ranges. Chemosphere 63:1280-1290. Walsh, M.E. 1989. Analytical Methods for Determining Nitroguanidine in Soil and Water. Special Report 89-35. U.S. Army Cold Regions Research and Engineering Laboratory, Hanover, NH.

The lost micro-deserts of the Patuxent River using landscape history, insect and plant specimens, and field work to detect and define a unique community

USGS Publications Warehouse

Droege, S.; Davis, C.A.; Steiner, W.E.; =Mawdsley, J.

2009-01-01

Historical and recent records of both plants and insects are synthesized for uplands along the eastern edge of Maryland?s Patuxent River from the edge of the Piedmont south to Jug Bay. This strip is characterized by deep sandy soils found in the Evesboro and Galestown sandy loams soil series. Within this narrow strip there exists a unique flora and fauna adapted to open dry sandy soils and occurring in small remnant patches associated with old sand mining operations and scattered protected areas. We illustrate the uniqueness of these sites using four groups, vascular plants, tenebrionid beetles (Coleoptera: Tenebrionidae), tiger beetles (Coleoptera: Cicindelidae), and bees (Hymenoptera: Apoidea: Anthophila). Within each of these groups, rare species were detected whose populations were locally restricted to this soil type and whose nearest known populations were often hundreds of kilometers away. In addition to documenting the direct conservation importance of these small sandy openings along the Patuxent, we contrast the lack of any indication from vertebrate inventories that this region is unique. The combination of plant and insect inventories appears to be a better means of clarifying a site?s importance than does any survey of a single taxonomic group.

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

[A site index model for Larix principis-rupprechtii plantation in Saihanba, north China].

PubMed

Wang, Dong-zhi; Zhang, Dong-yan; Jiang, Feng-ling; Bai, Ye; Zhang, Zhi-dong; Huang, Xuan-rui

2015-11-01

It is often difficult to estimate site indices for different types of plantation by using an ordinary site index model. The objective of this paper was to establish a site index model for plantations in varied site conditions, and assess the site qualities. In this study, a nonlinear mixed site index model was constructed based on data from the second class forest resources inventory and 173 temporary sample plots. The results showed that the main limiting factors for height growth of Larix principis-rupprechtii were elevation, slope, soil thickness and soil type. A linear regression model was constructed for the main constraining site factors and dominant tree height, with the coefficient of determination being 0.912, and the baseline age of Larix principis-rupprechtii determined as 20 years. The nonlinear mixed site index model parameters for the main site types were estimated (R2 > 0.85, the error between the predicted value and the actual value was in the range of -0.43 to 0.45, with an average root mean squared error (RMSE) in the range of 0.907 to 1.148). The estimation error between the predicted value and the actual value of dominant tree height for the main site types was in the confidence interval of [-0.95, 0.95]. The site quality of the high altitude-shady-sandy loam-medium soil layer was the highest and that of low altitude-sunny-sandy loam-medium soil layer was the lowest, while the other two sites were moderate.

[Virus adsorption from batch experiments as influenced by air-water interface].

PubMed

Zhang, Hui; Zhao, Bing-zi; Zhang, Jia-bao; Zhang, Cong-zhi; Wang, Qiu-ying; Chen, Ji

2007-12-01

The presence of air-water interface in batch sorption experiments may result in inaccurate estimation of virus adsorption onto various soils. A batch sorption experiment was conducted to compare the adsorption results of MS2 in different soils under presence/absence of air-water interface. Soils with sterilization/nonterilization treatment were used. Virus recovery efficiency in a blank experiment (no soil) was also evaluated as affected by different amount of air-water interface. The presence of air-water interface altered the results of virus adsorption in different soils with different extent, with Sandy fluvo-aquic soil being the most considerably affected, followed by Red loam soil, and the least being Red clay soil, probably because of different soil properties associated with virus adsorption/inactivation. Soil sterilization resulted in more significant difference of virus adsorption onto the Sandy fluvo-aquic soil between the presence and absence of air-water interface, while a reduced difference was observed in the Red loam soil. The presence of air-water interface significantly decreased virus recovery efficiency, with the values being decreased with increase in the amount of air-water interface. Soil particles likely prohibit viruses from reaching the air-water interface or alter the forces at the solid-water-air interface so that the results from the blank experiment did not truly represent results from control blank, which probably resulted in adsorption difference between presence and absence of the air-water interface.

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.

Persistence of Escherichia coli and Salmonella in surface soil following application of liquid hog manure for production of pickling cucumbers.

PubMed

Côté, Caroline; Quessy, Sylvain

2005-05-01

Liquid hog manure is routinely applied to farm land as a crop fertilizer. However, this practice raises food safety concerns, especially when manure is used on fruit and vegetable crops. The objectives of this project were to evaluate the persistence of Escherichia coli and Salmonella in surface soil after application of liquid hog manure to fields where pickling cucumbers were grown and to verify the microbiological quality of harvested cucumbers. Mineral fertilizers were replaced by liquid hog manure at various ratios in the production of pickling cucumbers in a 3-year field study. The experimental design was a randomized complete block comprising four replicates in sandy loam (years 1, 2, and 3) and loamy sand (year 3). Soil samples were taken at a depth of 20 cm every 2 weeks after June application of organic and inorganic fertilizers. Vegetable samples were also taken at harvest time. Liquid hog manure, soil, and vegetable (washed and unwashed) samples were analyzed for the presence of Salmonella and E. coli. An exponential decrease of E. coli populations was observed in surface soil after the application of manure. The estimated average time required to reach undetectable concentrations of E. coli in sandy loam varied from 56 to 70 days, whereas the absence of E. coli was estimated at 77 days in loamy sand. The maximal Salmonella persistence in soil was 54 days. E. coli and Salmonella were not detected in any vegetable samples.

Fuzzy logic-based assessment for mapping potential infiltration areas in low-gradient watersheds.

PubMed

Quiroz Londoño, Orlando Mauricio; Romanelli, Asunción; Lima, María Lourdes; Massone, Héctor Enrique; Martínez, Daniel Emilio

2016-07-01

This paper gives an account of the design a logic-based approach for identifying potential infiltration areas in low-gradient watersheds based on remote sensing data. This methodological framework is applied in a sector of the Pampa Plain, Argentina, which has high level of agricultural activities and large demands for groundwater supplies. Potential infiltration sites are assessed as a function of two primary topics: hydrologic and soil conditions. This model shows the state of each evaluated subwatershed respecting to its potential contribution to infiltration mainly based on easily measurable and commonly used parameters: drainage density, geomorphologic units, soil media, land-cover, slope and aspect (slope orientation). Mapped outputs from the logic model displayed 42% very low-low, 16% moderate, 41% high-very high contribution to potential infiltration in the whole watershed. Subwatersheds in the upper and lower section were identified as areas with high to very high potential infiltration according to the following media features: low drainage density (<1.5 km/km(2)), arable land and pastures as the main land-cover categories, sandy clay loam to loam - clay loam soils and with the geomorphological units named poorly drained plain, channelized drainage plain and, dunes and beaches. Copyright © 2016 Elsevier Ltd. All rights reserved.

Features of Scots pine radial growth in conditions of provenance trial

NASA Astrophysics Data System (ADS)

Kuzmin, S.

2012-12-01

Provenance trial of Scots pine in Boguchany forestry of Krasnoyarsk krai is conducted on two different soils - dark-grey loam forest soil and sod-podzol sandy soil. Complex of negative factors for plant growth and development appears in dry conditions of sandy soil. It could results in decrease of resistance to diseases. Sandy soils in different climatic zones have such common traits as low absorbing capacity, poorness of elemental nutrition, low microbiological activity and moisture capacity, very high water permeability. But Scots pine trees growing in such conditions could have certain advantages and perspectives of use. In the scope of climate change (global warming) the study of Scots pine growth on sandy soil become urgent because of more frequent appearance of dry seasons. Purpose of the work is revelation of radial growth features of Scots pine with different origin in dry conditions of sandy soil and assessment of external factors influence. The main feature of radial growth of majority of studied pine provenances in conditions of sandy soil is presence of significant variation of increment with distinct decline in 25-years old with loss of tree rings in a number of cases. The reason of it is complex of factors: deficit of June precipitation and next following outbreak of fungal disease. Found «frost rings» for all trees of studied clymatypes in 1992 are the consequence of temperature decline from May 21 to June 2 - from 23 C degrees up to 2 C. Perspective climatypes with biggest radial increments and least sensitivity to fungal disease were revealed.

Use of Pleurotus eous Strain P-31 Spent Mushroom Compost (SMC) as Soil Conditioner on the Growth and Yield Performance of Capsicum annuum L. and Solanum lycopersicon L. Seedlings under Greenhouse Conditions in Ghana

PubMed Central

Wiafe-Kwagyan, M; Odamtten, G T

2018-01-01

The objective of this study was to investigate the influence of spent mushroom compost of Pleurotus eous strain P-31 on the growth and yield performance of pepper and tomato seedlings under greenhouse conditions. Sandy loam soil was combined with different percentages of SMC to obtain the following combinations (0, 5, 10, 15, 20, 25 and 30) %. Lower concentrations SMC5, SMC10 and SMC15 promoted vegetative growth (plant height, leaf area, chlorophyll content, number of leaves and axillary branches) of the two test plants. Tomato seedlings grown in SMC10 recorded the highest plant height (50.3 ± 7.2cm); leaf area (378.8 ± 1.2cm2); number of floral buds (51) and flowers (28) whereas SMC5 recorded the highest chlorophyll content 34.1 ± 0.9CCI though SMC15 recorded the highest number of leaves (8). Tomato seedlings grown in SMC30 produced both the maximum number of fruits (8) with corresponding high weight (34.2 ± 7.7g). Pepper seedlings grown in lower concentrations (SMC5–15) recorded the highest plant heights (29.8–30.8cm), chlorophyll content (20.3CCI) and leaf area (53.5–66.2 cm2). Although the different combinations of sandy loam soil and SMC did not significantly (p ≥ 0.05) affect the number of axillary branches developed; different combinations significantly (p ≤ 0.05) affected the number of floral bud, flower and fruit, weight of fruits formed and value of each of these increased with increasing percentage of SMC. Pepper seedlings grown on SMC30 recorded the maximum number of floral buds (32.0 ± 3.6), number of flowers (19.4 ± 1.3), number of fruits (10.8 ± 1.2) and weight of fruits (31.9 ± 3.4g). Tomato seedlings raised on SMC100 (spent mushroom compost only) and soil only did not significantly (p ≥ 0.05) differ from each other however, was statistically significant (p ≤ 0.05) from amended sandy loam soil by all criteria investigated. The study shows that SMC provide favourable soil conditioners for the cultivation of fruits, vegetables and foliage crops as it improved growth and yield of tomato and pepper seedlings. PMID:29644023

Damage and Reproductive Potentials of Pratylenchus brachyurus and P. penetrans on soybean.

PubMed

Schmitt, D P; Barker, K R

1981-07-01

Damage and reproductive potentials of Pratylenchus brachyurus and P. penetrans on soybean, Glycine max, cvs. Essex, Forrest, and Lee 68, were determined in microplot tests. Cultivar Essex was generally tolerant to P. brachyurus. Yield of Forrest was suppressed linearly with increasing P(i)'s in the sandy soil (r = -0.92) and loamy sand soil (r = -0.99). Low to moderate P(i)'s in the sandy clay loam gave an increase in yields as compared to plants without nematodes. Yield was not affected by this nematode in muck. Lee 68 was very sensitive to P. penetrans in microplots. Yield vs. P(i) was fitted by a quadratic model (r = 0.82) with yield decreasing sharply as P(i)'s were increased. The reproduction of both species decreased with increases in P(i). Lee 68 was a good host for P. penetrans, whereas Essex and Forrest were fair to poor hosts for P. brachyurus.

Sediment Equilibrium and Diffusive Fluxes in Relation to Phosphorus Dynamics in the Turbid Minnesota River

DTIC Science & Technology

2009-01-01

extractable P and K in a sandy clay loam soil under continuous corn ( Zea mays L .). Can J Soil Sci 75:361-367. Zhang, T. Q., A. F. MacKenzie, B. C...diffusive P flux from deposited sediment stored in river channels may also play a role in soluble P control. Ranges in equilibrium partitioning between...largest plants in the State of Minnesota, discharge (average discharge = 1.8 m3 s-1) at effluent P concentrations of 1.5 mg L -1 or less. A 538-megawatt

Pesticide leaching through sandy and loamy fields - long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme.

PubMed

Rosenbom, Annette E; Olsen, Preben; Plauborg, Finn; Grant, Ruth; Juhler, René K; Brüsch, Walter; Kjær, Jeanne

2015-06-01

The European Union authorization procedure for pesticides includes an assessment of the leaching risk posed by pesticides and their degradation products (DP) with the aim of avoiding any unacceptable influence on groundwater. Twelve-year's results of the Danish Pesticide Leaching Assessment Programme reveal shortcomings to the procedure by having assessed leaching into groundwater of 43 pesticides applied in accordance with current regulations on agricultural fields, and 47 of their DP. Three types of leaching scenario were not fully captured by the procedure: long-term leaching of DP of pesticides applied on potato crops cultivated in sand, leaching of strongly sorbing pesticides after autumn application on loam, and leaching of various pesticides and their DP following early summer application on loam. Rapid preferential transport that bypasses the retardation of the plow layer primarily in autumn, but also during early summer, seems to dominate leaching in a number of those scenarios. Copyright © 2015 Elsevier Ltd. All rights reserved.

Application of Modular Modeling System to Predict Evaporation, Infiltration, Air Temperature, and Soil Moisture

NASA Technical Reports Server (NTRS)

Boggs, Johnny; Birgan, Latricia J.; Tsegaye, Teferi; Coleman, Tommy; Soman, Vishwas

1997-01-01

Models are used for numerous application including hydrology. The Modular Modeling System (MMS) is one of the few that can simulate a hydrology process. MMS was tested and used to compare infiltration, soil moisture, daily temperature, and potential and actual evaporation for the Elinsboro sandy loam soil and the Mattapex silty loam soil in the Microwave Radiometer Experiment of Soil Moisture Sensing at Beltsville Agriculture Research Test Site in Maryland. An input file for each location was created to nut the model. Graphs were plotted, and it was observed that the model gave a good representation for evaporation for both plots. In comparing the two plots, it was noted that infiltration and soil moisture tend to peak around the same time, temperature peaks in July and August and the peak evaporation was observed on September 15 and July 4 for the Elinsboro Mattapex plot respectively. MMS can be used successfully to predict hydrological processes as long as the proper input parameters are available.

Determination of Two Sulfonylurea Herbicides Residues in Soil Environment Using HPLC and Phytotoxicity of These Herbicides by Lentil Bioassay.

PubMed

Mehdizadeh, Mohammad; Alebrahim, Mohammad Taghi; Roushani, Mahmoud

2017-07-01

A HPLC-UV detection system was used for determination of sulfosulfuron and tribenuron methyl residues from soils. The soils were fortified with sulfosulfuron and tribenuron methyl at rates of 26 and 15 g a.i. ha -1 respectively and samples were taken randomly on 0 (2 h), 1, 2, 4, 10, 20, 40, 60, 90 and 120 days after treatment. The final extracts were prepared for analysis by HPLC. The results showed that degradation of both herbicides in the silty loam soil was faster than sandy loam soil. Half-life of sulfosulfuron was ranged from 5.37 to 10.82 days however this value for tribenuron methyl was ranged from 3.23 to 5.72 days on different soils. The residue of both herbicides at 120 days after application in wheat field had no toxicitic effect on lentil. It was concluded that HPLC analysis procedure was an appropriate method for determination of these herbicides from soils.

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

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.

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.

EVALUATION OF FROST HEAVE ON WASTE TRANSFER LINES WITH SHALLOW DEPTHS IN DST (DOUBLE SHELL TANK) FARMS

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

HAQ MA

2009-05-12

The purpose of this document is to evaluate the effect of frost heave on waste transfer lines with shallow depths in DST farms. Because of the insulation, well compacted sandy material around waste transfer lines, the type of sandy and gravel soil, and relatively low precipitation at Hanford site, it is concluded that waste transfer lines with one foot of soil covers (sandy cushion material and insulation) are not expected to undergo frost heave damaging effects.

Using Color, Texture and Object-Based Image Analysis of Multi-Temporal Camera Data to Monitor Soil Aggregate Breakdown

PubMed Central

Ymeti, Irena; van der Werff, Harald; Shrestha, Dhruba Pikha; Jetten, Victor G.; Lievens, Caroline; van der Meer, Freek

2017-01-01

Remote sensing has shown its potential to assess soil properties and is a fast and non-destructive method for monitoring soil surface changes. In this paper, we monitor soil aggregate breakdown under natural conditions. From November 2014 to February 2015, images and weather data were collected on a daily basis from five soils susceptible to detachment (Silty Loam with various organic matter content, Loam and Sandy Loam). Three techniques that vary in image processing complexity and user interaction were tested for the ability of monitoring aggregate breakdown. Considering that the soil surface roughness causes shadow cast, the blue/red band ratio is utilized to observe the soil aggregate changes. Dealing with images with high spatial resolution, image texture entropy, which reflects the process of soil aggregate breakdown, is used. In addition, the Huang thresholding technique, which allows estimation of the image area occupied by soil aggregate, is performed. Our results show that all three techniques indicate soil aggregate breakdown over time. The shadow ratio shows a gradual change over time with no details related to weather conditions. Both the entropy and the Huang thresholding technique show variations of soil aggregate breakdown responding to weather conditions. Using data obtained with a regular camera, we found that freezing–thawing cycles are the cause of soil aggregate breakdown. PMID:28556803

Key parameters in testing biodegradation of bio-based materials in soil.

PubMed

Briassoulis, D; Mistriotis, A

2018-09-01

Biodegradation of plastics in soil is currently tested by international standard testing methods (e.g. ISO 17556-12 or ASTM D5988-12). Although these testing methods have been developed for plastics, it has been shown in project KBBPPS that they can be extended also to lubricants with small modifications. Reproducibility is a critical issue regarding biodegradation tests in the laboratory. Among the main testing variables are the soil types and nutrients available (mainly nitrogen). For this reason, the effect of the soil type on the biodegradation rates of various bio-based materials (cellulose and lubricants) was tested for five different natural soil types (loam, loamy sand, clay, clay-loam, and silt-loam organic). It was shown that use of samples containing 1 g of C in a substrate of 300 g of soil with the addition of 0.1 g of N as nutrient strongly improves the reproducibility of the test making the results practically independent of the soil type with the exception of the organic soil. The sandy soil was found to need addition of higher amount of nutrients to exhibit similar biodegradation rates as those achieved with the other soil types. Therefore, natural soils can be used for Standard biodegradation tests of bio-based materials yielding reproducible results with the addition of appropriate nutrients. Copyright © 2018 Elsevier Ltd. All rights reserved.

Using Color, Texture and Object-Based Image Analysis of Multi-Temporal Camera Data to Monitor Soil Aggregate Breakdown.

PubMed

Ymeti, Irena; van der Werff, Harald; Shrestha, Dhruba Pikha; Jetten, Victor G; Lievens, Caroline; van der Meer, Freek

2017-05-30

Remote sensing has shown its potential to assess soil properties and is a fast and non-destructive method for monitoring soil surface changes. In this paper, we monitor soil aggregate breakdown under natural conditions. From November 2014 to February 2015, images and weather data were collected on a daily basis from five soils susceptible to detachment (Silty Loam with various organic matter content, Loam and Sandy Loam). Three techniques that vary in image processing complexity and user interaction were tested for the ability of monitoring aggregate breakdown. Considering that the soil surface roughness causes shadow cast, the blue/red band ratio is utilized to observe the soil aggregate changes. Dealing with images with high spatial resolution, image texture entropy, which reflects the process of soil aggregate breakdown, is used. In addition, the Huang thresholding technique, which allows estimation of the image area occupied by soil aggregate, is performed. Our results show that all three techniques indicate soil aggregate breakdown over time. The shadow ratio shows a gradual change over time with no details related to weather conditions. Both the entropy and the Huang thresholding technique show variations of soil aggregate breakdown responding to weather conditions. Using data obtained with a regular camera, we found that freezing-thawing cycles are the cause of soil aggregate breakdown.

Soil physicochemical properties to evaluate soil degradation under different land use types in a high rainfall tropical region: A case study from South Sulawesi, Indonesia

NASA Astrophysics Data System (ADS)

Ahmad, A.; Lopulisa, C.; Imran, A. M.; Baja, S.

2018-05-01

Intensive cropping in the tropical region always becomes one of important driving forces of soil degradation. The primary aim of this study is to analyze the states and the dynamics of soil physicochemical properties to evaluate soil degradation in the tropical region a high rainfall on agricultural areas in South Sulawesi. A number of soil characteristics were analyzed for physical and chemical properties, and clay minerals with X-ray diffractometer. The degree of soil degradation is determined using Wischmeier and Smith equation. This study reveals that mean annual precipitation in 1979-2016 ranged from 1853.15 to 2981.30 mm/year. For land used for paddy field, palm oil, cacao and coffee plantation, the texture dominated with silt loam-clay loam, cation exchange capacity was 18.63-26.32 cmol+ kg-1, 0.98-2.91% of C-organic, 32-55% of base saturation, 0.1-3.5 cm h-1 of permeability, soil clay minerals were montmorillonite-kaolinite-halloysite, and the index erodibility was 0.3-0.5. Land used for mixed plants and shrubs, the texture dominated with silt loam-sandy clay loam, cation exchange capacity was 18.63-27.12 cmol+ kg-1, 1.09-2.89% of C-organic, 32-55% of base saturation, 0.2-4.9 cm/h of permeability, soil clay minerals were kaolinite-halloysite, and index erodibility was 0.1-0.3. Land use for cultivated in the high intensity of rainfall has changed the physicochemical properties of soils, but cultivated in monoculture has at some degree increased soil erodibility.

Effects of Nitramine Explosive CL-20 on the Soil Microinvertebrate Community in a Sandy Loam Soil

DTIC Science & Technology

2013-09-01

with soil invertebrates using the earthworm Eisenia fetida (ISO,1998a), potworm E. crypticus (ISO, 2004), and collembolan Folsomia candida (ISO,1998b...survival of microarthropods and nematodes, compared with reproduction toxicity data for E. fetida, E. andrei, E. crypticus, E. albidus, and F. candida ...fetida >500 0.1 95% CI ND 0.07–0.13 Enchytraeus crypticus 18 0.3 95% CI 2.6–34 0.2–0.4 Folsomia candida 32 0.7 95% CI 9–55 0.36–1.06 Notes

Compaction Characteristics of Earth-Rock Mixtures. Report 1. Vicksburg Silty Clay and Degray Dam Clayey Sandy Gravel

DTIC Science & Technology

1973-05-01

dry density of total sample Yf = dry unit weight of finer fraction G = bulk specific gravity of coarser fraction (based on ovendry weightq). Same as G...ttl~o o 40 oe o Fig. ii. Theoretical and experimental densities of eclayey sandy gravel (GC) DeGray meterial expressions require tests performed on

Sorption-desorption behavior of PCP on soil organic matter and clay minerals.

PubMed

Pu, Xunchi; Cutright, Teresa J

2006-08-01

Pentachlorophenol (PCP) contamination is a severe environmental problem due to its widespread occurrence, toxicity and recalcitrance. In order to gain a better understanding of the fate of PCP in soils, the role of the soil organic matter (SOM) and clay minerals in the PCP sorption-desorption was studied on two bulk field soils, two subsoils (i.e., SOM or clay-removed soil) and two artificial soils. The two field soils used were a silty loam from New Mexico (NM) containing 10% clay and a sandy-clay-loam from Colombia (CO) South America comprised of 18% clay minerals. The bulk CO soil containing kaolinite sorbed significantly less PCP than the NM soil. All soils depicted an apparent hysteresis during sorption. The CO bulk and subsoils desorbed 14-20% and 15-26% of the sorbed PCP respectively whereas the NM bulk and subsoils desorbed only 4-12% and 5-16%, respectively. Experiments conducted with pure clay and artificial soils indicated that the expandable clay minerals were key sorbent material. Additional studies to investigate the interaction between SOM and clay minerals are needed to fully understand sorptive phenomena.

Enzyme Sorption onto Soil and Biocarbon Amendments Alters Catalytic Capacity and Depends on the Specific Protein and pH

NASA Astrophysics Data System (ADS)

Foster, E.; Fogle, E. J.; Cotrufo, M. F.

2017-12-01

Enzymes catalyze biogeochemical reactions in soils and play a key role in nutrient cycling in agricultural systems. Often, to increase soil nutrients, agricultural managers add organic amendments and have recently experimented with charcoal-like biocarbon products. These amendments can enhance soil water and nutrient holding capacity through increasing porosity. However, the large surface area of the biocarbon has the potential to sorb nutrients and other organic molecules. Does the biocarbon decrease nutrient cycling through sorption of enzymes? In a laboratory setting, we compared the interaction of two purified enzymes β-glucosidase and acid phosphatase with a sandy clay loam and two biocarbons. We quantified the sorbed enzymes at three different pHs using a Bradford protein assay and then measured the activity of the sorbed enzyme via high-throughput fluorometric analysis. Both sorption and activity depended upon the solid phase, pH, and specific enzyme. Overall the high surface area biocarbon impacted the catalytic capacity of the enzymes more than the loam soil, which may have implications for soil nutrient management with these organic amendments.

A novel low-cost open-hardware platform for monitoring soil water content and multiple soil-air-vegetation parameters.

PubMed

Bitella, Giovanni; Rossi, Roberta; Bochicchio, Rocco; Perniola, Michele; Amato, Mariana

2014-10-21

Monitoring soil water content at high spatio-temporal resolution and coupled to other sensor data is crucial for applications oriented towards water sustainability in agriculture, such as precision irrigation or phenotyping root traits for drought tolerance. The cost of instrumentation, however, limits measurement frequency and number of sensors. The objective of this work was to design a low cost "open hardware" platform for multi-sensor measurements including water content at different depths, air and soil temperatures. The system is based on an open-source ARDUINO microcontroller-board, programmed in a simple integrated development environment (IDE). Low cost high-frequency dielectric probes were used in the platform and lab tested on three non-saline soils (ECe1: 2.5 < 0.1 mS/cm). Empirical calibration curves were subjected to cross-validation (leave-one-out method), and normalized root mean square error (NRMSE) were respectively 0.09 for the overall model, 0.09 for the sandy soil, 0.07 for the clay loam and 0.08 for the sandy loam. The overall model (pooled soil data) fitted the data very well (R2 = 0.89) showing a high stability, being able to generate very similar RMSEs during training and validation (RMSE(training) = 2.63; RMSE(validation) = 2.61). Data recorded on the card were automatically sent to a remote server allowing repeated field-data quality checks. This work provides a framework for the replication and upgrading of a customized low cost platform, consistent with the open source approach whereby sharing information on equipment design and software facilitates the adoption and continuous improvement of existing technologies.

A Novel Low-Cost Open-Hardware Platform for Monitoring Soil Water Content and Multiple Soil-Air-Vegetation Parameters

PubMed Central

Bitella, Giovanni; Rossi, Roberta; Bochicchio, Rocco; Perniola, Michele; Amato, Mariana

2014-01-01

Monitoring soil water content at high spatio-temporal resolution and coupled to other sensor data is crucial for applications oriented towards water sustainability in agriculture, such as precision irrigation or phenotyping root traits for drought tolerance. The cost of instrumentation, however, limits measurement frequency and number of sensors. The objective of this work was to design a low cost “open hardware” platform for multi-sensor measurements including water content at different depths, air and soil temperatures. The system is based on an open-source ARDUINO microcontroller-board, programmed in a simple integrated development environment (IDE). Low cost high-frequency dielectric probes were used in the platform and lab tested on three non-saline soils (ECe1: 2.5 < 0.1 mS/cm). Empirical calibration curves were subjected to cross-validation (leave-one-out method), and normalized root mean square error (NRMSE) were respectively 0.09 for the overall model, 0.09 for the sandy soil, 0.07 for the clay loam and 0.08 for the sandy loam. The overall model (pooled soil data) fitted the data very well (R2 = 0.89) showing a high stability, being able to generate very similar RMSEs during training and validation (RMSEtraining = 2.63; RMSEvalidation = 2.61). Data recorded on the card were automatically sent to a remote server allowing repeated field-data quality checks. This work provides a framework for the replication and upgrading of a customized low cost platform, consistent with the open source approach whereby sharing information on equipment design and software facilitates the adoption and continuous improvement of existing technologies. PMID:25337742

Nebraska's groundwater legacy: Nitrate contamination beneath irrigated cropland

PubMed Central

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

2014-01-01

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

Bioaugmentation of Soil Contaminated with Azoxystrobin.

PubMed

Baćmaga, Małgorzata; Wyszkowska, Jadwiga; Kucharski, Jan

2017-01-01

The presence of fungicides in the natural environment, either resulting from deliberate actions or not, has become a serious threat to many ecosystems, including soil. This can be prevented by taking appropriate measures to clear the environment of organic contamination, including fungicides. Therefore, a study was conducted aimed at determining the effect of bioaugmentation of soil exposed to azoxystrobin on its degradation and activity of selected enzymes (dehydrogenases, catalase, urease, acidic phosphatase, alkaline phosphatase). A model experiment was conducted for 90 days on two types of soil: loamy sand (pH KCl -5.6) and sandy loam (pH KCl -7.0), which were contaminated by azoxystrobin at 22.50 mg kg -1 DM of soil and inoculated with a specific consortium of microorganisms. Four strains of bacteria were used in the experiment ( Bacillus sp. LM655314.1, B. cereus KC848897.1, B. weihenstephanensis KF831381.1, B. megaterium KJ843149.1) and two strains of mould fungi ( Aphanoascus terreus AB861677.1, A. fulvescens JN943451.1). Inoculation of soil with the consortium of microorganisms accelerated the degradation of azoxystrobin. The isolated microorganisms were more active in loamy sand because within 90 days azoxystrobin was degraded by 24% ( Bacillus sp., B. cereus , B. weihenstephanensis , B. megaterium ) to 78% ( Aphanoascus terreus , A. fulvescens ). In sandy loam, azoxystrobin was degraded by 9% ( Aphanoascus terreus , A. fulvescens ) to 29% ( Bacillus sp., B. cereus , B. weihenstephanensis , B. megaterium and Aphanoascus terreus , A. fulvescens ). The activity of soil enzymes was also changed as a result of inoculation of soil with microorganisms. The activity of all of the enzymes under study was found to have increased when soil augmentation was performed.

Barley responses to combined waterlogging and salinity stress: separating effects of oxygen deprivation and elemental toxicity

PubMed Central

Zeng, Fanrong; Shabala, Lana; Zhou, Meixue; Zhang, Guoping; Shabala, Sergey

2013-01-01

Salinity and waterlogging are two major factors affecting crop production around the world and often occur together (e.g., salt brought to the surface by rising water tables). While the physiological and molecular mechanisms of plant responses to each of these environmental constraints are studied in detail, the mechanisms underlying plant tolerance to their combined stress are much less understood. In this study, whole-plant physiological responses to individual/combined salinity and waterlogging stresses were studied using two barley varieties grown in either vermiculite (semi-hydroponics) or sandy loam. Two weeks of combined salinity and waterlogging treatment significantly decreased plant biomass, chlorophyll content, maximal quantum efficiency of PSII and water content (WC) in both varieties, while the percentage of chlorotic and necrotic leaves and leaf sap osmolality increased. The adverse effects of the combined stresses were much stronger in the waterlogging-sensitive variety Naso Nijo. Compared with salinity stress alone, the combined stress resulted in a 2-fold increase in leaf Na+, but a 40% decrease in leaf K+ content. Importantly, the effects of the combined stress were more pronounced in sandy loam compared with vermiculite and correlated with changes in the soil redox potential and accumulation of Mn and Fe in the waterlogged soils. It is concluded that hypoxia alone is not a major factor determining differential plant growth under adverse stress conditions, and that elemental toxicities resulting from changes in soil redox potential have a major impact on genotypic differences in plant physiological and agronomical responses. These results are further discussed in the context of plant breeding for waterlogging stress tolerance. PMID:23967003

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

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.

Transformation of corn plant residues in loamy and sandy substrates

NASA Astrophysics Data System (ADS)

Mal'tseva, A. N.; Zolotareva, B. N.; Pinskii, D. L.

2014-05-01

The mineralization and humification dynamics of corn plant residues in loamy and sandy substrates have been studied under laboratory conditions. It has been shown that the dynamics are determined by the undulating development laws of the microbial community under constant temperature and moisture conditions. At the same time, the intensity and final results of the processes significantly differ depending on the composition and properties of the mineral substrate. The loss of Corg during the mineralization and the content of newly formed humic substances reached the maximum values a month after the beginning of the experiment. The mineralization is more intensive in sand at the early stages, and the humification is more active in loam throughout the incubation period. The loamy substrate has better protective properties compared to the sand; therefore, it favors the accumulation of significant amounts of fulvic acids (FAs), along with humic acids (HAs), and causes the relative fulvatization of the humic substances. It has been found using densimetric fractionation and Fourier IR spectroscopy that the different mineralogy of the fractions results in differences in the chemical composition of the formed mineral-organic compounds of newly formed humic substances, mainly due to carboxyl and nitrogen-containing groups. The similarity of the humification products in the heavy fractions of the loamy and sandy substrates has been revealed.

Humic substances as a washing agent for Cd-contaminated soils.

PubMed

Meng, Fande; Yuan, Guodong; Wei, Jing; Bi, Dongxue; Ok, Yong Sik; Wang, Hailong

2017-08-01

Cost-effective and eco-friendly washing agents are in demand for Cd contaminated soils. Here, we used leonardite-derived humic substances to wash different types of Cd-contaminated soils, namely, a silty loam (Soil 1), a silty clay loam (Soil 2), and a sandy loam (Soil 3). Washing conditions were investigated for their effects on Cd removal efficiency. Cadmium removal was enhanced by a high humic substance concentration, long washing time, near neutral pH, and large solution/soil ratio. Based on the tradeoff between efficiency and cost, an optimum working condition was established as follows: humic substance concentration (3150 mg C/L), solution pH (6.0), washing time (2 h) and a washing solution/soil ratio (5). A single washing removed 0.55 mg Cd/kg from Soil 1 (1.33 mg Cd/kg), 2.32 mg Cd/kg from Soil 2 (6.57 mg Cd/kg), and 1.97 mg Cd/kg from Soil 3 (2.63 mg Cd/kg). Cd in effluents was effectively treated by adding a small dose of calcium hydroxide, reducing its concentration below the discharge limit of 0.1 mg/L in China. Being cost-effective and safe, humic substances have a great potential to replace common washing agents for the remediation of Cd-contaminated soils. Besides being environmentally benign, humic substances can improve soil physical, chemical, and biological properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

Uchrin, C.G.; Mangels, G.

Studies examining sorption equilibria of benzene and toluene to New Jersey coastal plain aquifer solids were performed. Adsorption to the Cohansey aquifer solids, a coarse to fine grade sand with a 2.6% organic carbon content, and to the Potomac-Raritan-Magothy aquifer solids, a sandy loam with a 1.3% organic carbon content, was found to be dependent on adsorber mass. Equilibrium adsorption could be characterized by either linear or Freundlich isotherms. Toluene exhibited a greater affinity to sorb than benzene. Greater adsorption was in general observed for both substances to the Cohansey material, which was attributed to its greater organic matter (carbon)more » content. Consecutive desorption experiments displayed an apparent hysteresis.« less

Bacterial mobilization and transport through manure enriched soils: Experiment and modeling.

PubMed

Sepehrnia, N; Memarianfard, L; Moosavi, A A; Bachmann, J; Guggenberger, G; Rezanezhad, F

2017-10-01

A precise evaluation of bacteria transport and mathematical investigations are useful for best management practices in agroecosystems. In this study, using laboratory experiments and modeling approaches, we assess the transport of bacteria released from three types of manure (cow, sheep, and poultry) to find the importance of the common manures in agricultural activities in soil and water pollution. Thirty six intact soil columns with different textures (sandy, loamy, and silty clay loam) were sampled. Fecal coliform leaching from layers of the manures on the soil surface was conducted under steady-state saturated flow conditions at 20 °C for up to four Pore Volumes (PVs). Separate leaching experiments were conducted to obtain the initial concentrations of bacteria released from the manures (Co). Influent (Co) and effluent (C) bacteria concentrations were measured by the plate-count method and the normalized concentrations (C/C0) were plotted versus PV representing the breakthrough curves (BTCs). Transport parameters were predicted using the attachment/detachment model (two-kinetic site) in HYDRUS-1D. Simulations fitted well the experimental data (R 2  = 0.50-0.96). The attachment, detachment, and straining coefficients of bacteria were more influenced by the soils treated with cow manure compared to the sheep and poultry manures. Influent curves of fecal coliforms from the manures (leached without soil) illustrated that the poultry manure had the highest potential to pollute the effluent water from the soils in term of concentration, but the BTCs and simulated data related to the treated soils illustrated that the physical shape of cow manure was more important to both straining and detachment of bacteria back into the soil solution. Detachment trends of bacteria were observed through loam and silty clay loam soils treated with cow manure compared to the cow manure enriched sandy soil. We conclude that management strategies must specifically minimize the effect of fecal coliform concentrations before field application, especially for the combination of poultry and cow manures, which has higher solubility and tailing behavior, respectively. Interestingly, the addition of sheep manure with all three soils had the lowest mobilization of bacteria. We also suggest studying the chemistry of soil solution affected by manures to present all relevant information which affect bacterial movement through soils during leaching. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Physically-based Model for Predicting Soil Moisture Dynamics in Wetlands

NASA Astrophysics Data System (ADS)

Kalin, L.; Rezaeianzadeh, M.; Hantush, M. M.

2017-12-01

Wetlands are promoted as green infrastructures because of their characteristics in retaining and filtering water. In wetlands going through wetting/drying cycles, simulation of nutrient processes and biogeochemical reactions in both ponded and unsaturated wetland zones are needed for an improved understanding of wetland functioning for water quality improvement. The physically-based WetQual model can simulate the hydrology and nutrient and sediment cycles in natural and constructed wetlands. WetQual can be used in continuously flooded environments or in wetlands going through wetting/drying cycles. Currently, WetQual relies on 1-D Richards' Equation (RE) to simulate soil moisture dynamics in unponded parts of the wetlands. This is unnecessarily complex because as a lumped model, WetQual only requires average moisture contents. In this paper, we present a depth-averaged solution to the 1-D RE, called DARE, to simulate the average moisture content of the root zone and the layer below it in unsaturated parts of wetlands. DARE converts the PDE of the RE into ODEs; thus it is computationally more efficient. This method takes into account the plant uptake and groundwater table fluctuations, which are commonly overlooked in hydrologic models dealing with wetlands undergoing wetting and drying cycles. For verification purposes, DARE solutions were compared to Hydrus-1D model, which uses full RE, under gravity drainage only assumption and full-term equations. Model verifications were carried out under various top boundary conditions: no ponding at all, ponding at some point, and no rain. Through hypothetical scenarios and actual atmospheric data, the utility of DARE was demonstrated. Gravity drainage version of DARE worked well in comparison to Hydrus-1D, under all the assigned atmospheric boundary conditions of varying fluxes for all examined soil types (sandy loam, loam, sandy clay loam, and sand). The full-term version of DARE offers reasonable accuracy compared to the full RE solutions from Hydrus-1D, with a significant reduction in computational time. The full-term version of DARE estimated the moisture content with better accuracy for the root zone by considering zero pressure head at a fixed groundwater depth as the bottom boundary condition. The accuracy of this model is lower for the second layer.

Effects of slash, machine passes, and soil moisture on penetration resistance in a cut-to-length harvesting

Treesearch

Han-Sup Han; Debbie Page-Dumroese; Sang-Kyun Han; Joanne Tirocke

2006-01-01

Multiple entries into forest stands are often needed for fire hazard reduction and ecosystem restoration treatments in the Inland-Northwest U.S.A. region. However, soil compaction occurring from mechanized harvesting operations often remains for many years and may contribute to a decline in long-term site productivity. A controlled experiment on a silt loam soil was...

[Distribution of soil organic carbon, total nitrogen, total phosphorus and water stable aggregates of cropland with different soil textures on the Loess Plateau, Northwest China].

PubMed

Ge, Nan Nan; Shi, Yun; Yang, Xian Long; Zhang, Qing Yin; Li, Xue Zhang; Jia, Xiao Xu; Shao, Ming An; Wei, Xiao Rong

2017-05-18

In this study, combined with field investigation and laboratory analyses, we assessed the distribution of soil organic carbon, nitrogen, phosphorous contents and their stoichiometric ratios, and the distribution of soil water stable aggregates along a soil texture gradient in the cropland of the Loess Plateau to understand the effect of soil texture and the regulation of soil aggregates on soil fertility in cropland. The results showed that, with the change from fine soils to coarse soils along the texture gradient (loam clay→ clay loam→ sandy loam), the contents of macroaggregates, organic carbon, nitrogen, phosphorous and their stoichiometric ratios decreased, while pH value and microaggregates content showed an opposite changing pattern. The contents of macroaggregates, organic carbon, nitrogen, phosphorous, and C/P and N/P were significantly increased, but pH value and microaggregates content were significantly decreased with increasing the soil clay content. Furthermore, the contents of organic carbon, nitrogen, phosphorous, and C/P and N/P increased with the increase of macroaggregates content. These results indicated that soil fertility in croplands at a regional scale was mainly determined by soil texture, and was regulated by soil macroaggregates.

Effect of bovine manure on fecal coliform attachment to soil and soil particles of different sizes.

PubMed

Guber, Andrey K; Pachepsky, Yakov A; Shelton, Daniel R; Yu, Olivia

2007-05-01

Manure-borne bacteria can be transported in runoff as free cells, cells attached to soil particles, and cells attached to manure particles. The objectives of this work were to compare the attachment of fecal coliforms (FC) to different soils and soil fractions and to assess the effect of bovine manure on FC attachment to soil and soil fractions. Three sand fractions of different sizes, the silt fraction, and the clay fraction of loam and sandy clay loam soils were separated and used along with soil samples in batch attachment experiments with water-FC suspensions and water-manure-FC suspensions. In the absence of manure colloids, bacterial attachment to soil, silt, and clay particles was much higher than the attachment to sand particles having no organic coating. The attachment to the coated sand particles was similar to the attachment to silt and clay. Manure colloids in suspensions decreased bacterial attachment to soils, clay and silt fractions, and coated sand fractions, but did not decrease the attachment to sand fractions without the coating. The low attachment of bacteria to silt and clay particles in the presence of manure colloids may cause predominantly free-cell transport of manure-borne FC in runoff.

Effects of sorbate speciation on sorption of selected sulfonamides in three loamy soils

USGS Publications Warehouse

Kurwadkar , Sudarshan T.; Adams, Craig D.; Meyer, Michael T.; Kolpin, Dana W.

2007-01-01

Sorption of sulfamethazine (SMN) and sulfathiazole (STZ) was investigated in three soils, a North Carolina loamy sand, an Iowa sandy loam, and a Missouri loam, under various pH conditions. A significant increase in the sorption coefficient (KD) was observed in all three soils, as the sulfonamides converted from an anionic form at higher pH to a neutral/cationic form at lower pH. Above pH 7.5, sulfonamides exist primarily in anionic form and have higher aqueous solubility and no cationic character, thereby consequently leading to lower sorption to soils. The effect of speciation on sorption is not the same for all sulfonamides; it is a function of the pH of the soil and the pKa of the sulfonamides. The results indicate that, for the soils under investigation, SMN has comparatively lower KD values than STZ. The pH-dependent sorption of sulfonamides was observed to be consistent in all three soils investigated. The KD values for each speciated formcationic, neutral, and anionicwere calculated using an empirical model in which the species-specific sorption coefficients (KD0, KD1, and KD2) were weighted with their respective fractions present at any given pH.

Dielectrophoretic sample preparation for environmental monitoring of microorganisms: Soil particle removal.

PubMed

Fatoyinbo, Henry O; McDonnell, Martin C; Hughes, Michael P

2014-07-01

Detection of pathogens from environmental samples is often hampered by sensors interacting with environmental particles such as soot, pollen, or environmental dust such as soil or clay. These particles may be of similar size to the target bacterium, preventing removal by filtration, but may non-specifically bind to sensor surfaces, fouling them and causing artefactual results. In this paper, we report the selective manipulation of soil particles using an AC electrokinetic microfluidic system. Four heterogeneous soil samples (smectic clay, kaolinitic clay, peaty loam, and sandy loam) were characterised using dielectrophoresis to identify the electrical difference to a target organism. A flow-cell device was then constructed to evaluate dielectrophoretic separation of bacteria and clay in a continous flow through mode. The average separation efficiency of the system across all soil types was found to be 68.7% with a maximal separation efficiency for kaolinitic clay at 87.6%. This represents the first attempt to separate soil particles from bacteria using dielectrophoresis and indicate that the technique shows significant promise; with appropriate system optimisation, we believe that this preliminary study represents an opportunity to develop a simple yet highly effective sample processing system.

Environmental fate of two sulfonamide antimicrobial agents in soil.

PubMed

Accinelli, Cesare; Koskinen, William C; Becker, Joanna M; Sadowsky, Michael J

2007-04-04

Veterinary antimicrobial agents have been detected in a number of environmental samples, including agricultural soils. In this study, we investigated the persistence and sorption of the sulfonamides sulfamethazine (SMZ) and sulfachloropyridine (SCP) in soil and their potential effects on soil microorganisms. The sulfonamides dissipated more rapidly from the silt loam soil as compared to the sandy soil. Average half-lives of SMZ and SPC among the two soils were 18.6 and 21.3 days, respectively. The presence of liquid swine slurry (5% v/w) decreased sulfonamide persistence in the silt loam soil. The lower persistence of the antimicrobials in liquid swine slurry-amended soil was likely due to higher microbial activity, as compared to unamended soil, and/or to the greater bioavailability of the sulfonamides to degrading microorganisms, as estimated by sorption isotherms. Concentrations of SMZ and SPC up to 100 microg g-1 had no effect on antimicrobial degradation rates and soil microorganisms. These studies suggest that higher sulfonamide concentrations would be necessary to affect the main processes controlling their environmental fates in soil, but at the concentrations normally found in the environment, there would be little or no effects.

Effects of biochar and alkaline amendments on cadmium immobilization, selected nutrient and cadmium concentrations of lettuce (Lactuca sativa) in two contrasting soils.

PubMed

Woldetsadik, Desta; Drechsel, Pay; Keraita, Bernard; Marschner, Bernd; Itanna, Fisseha; Gebrekidan, Heluf

2016-01-01

To assess the efficiency of seven treatments including biochars produced from dried faecal matter and manures as stabilizing agents of cadmium (Cd)-spiked soils, lettuce was grown in glasshouse on two contrasting soils. The soils used were moderately fertile silty loam and less fertile sandy loam and the applied treatments were 7 % w/w. The reduction of bioavailable Cd (ammonium nitrate extractable) and its phytoavailability for lettuce were used as assessment criteria in the evaluation of stabilization performance of each treatment. Moreover, the agronomic values of the treatments were also investigated. Ammonium nitrate extraction results indicated that faecal matter biochar, cow manure biochar and lime significantly reduced bioavailable Cd by 84-87, 65-68 and 82-91 %, respectively, as compared to the spiked controls. Unpredictably, coffee husk biochar induced significant increment of Cd in NH4NO3 extracts. The immobilization potential of faecal matter biochar and lime were superior than the other treatments. However, lime and egg shell promoted statistically lower yield and P, K and Zn concentrations response of lettuce plants compared to the biochar treatments. The lowest Cd and highest P tissue concentrations of lettuce plants were induced by faecal matter and cow manure biochar treatments in both soils. Additionally, the greatest Cd phytoavailability reduction for lettuce was induced by poultry litter and cow manure biochars in the silty loam soil. Our results indicate that faecal matter and animal manure biochars have shown great potential to promote Cd immobilization and lettuce growth response in heavily contaminated agricultural fields.

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.

Toxicity and uptake of cyclic nitramine explosives in ryegrass Lolium perenne.

PubMed

Rocheleau, Sylvie; Lachance, Bernard; Kuperman, Roman G; Hawari, Jalal; Thiboutot, Sonia; Ampleman, Guy; Sunahara, Geoffrey I

2008-11-01

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) are cyclic nitramines used as explosives. Their ecotoxicities have been characterized incompletely and little is known about their accumulation potential in soil organisms. We assessed the toxicity and uptake of these explosives in perennial ryegrass Lolium perenne L. exposed in a Sassafras sandy loam (SSL) or in a sandy soil (DRDC, CL-20 only) containing contrasting clay contents (11% and 0.3%, respectively). A 21-d exposure to RDX, HMX or CL-20 in either soil had no adverse effects on ryegrass growth. RDX and HMX were translocated to ryegrass shoots, with bioconcentration factors (BCF) of up to 15 and 11, respectively. In contrast, CL-20 was taken up by the roots (BCF up to 19) with no translocation to the shoots. These studies showed that RDX, HMX, and CL-20 can accumulate in plants and may potentially pose a risk of biomagnification across the food chain.

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.

The long-term effects of silvicultural thinning and partial cutting on soil compaction in red pine (Pinus resinosa Ait.) and northern hardwood stands in the northern Great Lakes Region of the United States

Treesearch

Rachel A. Tarpey; Martin F. Jurgensen; Brian J. Palik; Randy K. Kolka

2008-01-01

Periodic silvicultural thinnings (23.0, 27.6, 32.1 m2 ha-1 residual basal area) in a red pine stand growing on a sandy soil in north-central Minnesota over a 57-yr period increased soil compaction as the intensity of the thinning treatment increased. Of the three different methods used to measure soil compaction (bulk...

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.

Calibrated Hydrothermal Parameters, Barrow, Alaska, 2013

DOE Data Explorer

Atchley, Adam; Painter, Scott; Harp, Dylan; Coon, Ethan; Wilson, Cathy; Liljedahl, Anna; Romanovsky, Vladimir

2015-01-29

A model-observation-experiment process (ModEx) is used to generate three 1D models of characteristic micro-topographical land-formations, which are capable of simulating present active thaw layer (ALT) from current climate conditions. Each column was used in a coupled calibration to identify moss, peat and mineral soil hydrothermal properties to be used in up-scaled simulations. Observational soil temperature data from a tundra site located near Barrow, AK (Area C) is used to calibrate thermal properties of moss, peat, and sandy loam soil to be used in the multiphysics Advanced Terrestrial Simulator (ATS) models. Simulation results are a list of calibrated hydrothermal parameters for moss, peat, and mineral soil hydrothermal parameters.

Controllability of runoff and soil loss from small plots treated by vinasse-produced biochar.

PubMed

Sadeghi, Seyed Hamidreza; Hazbavi, Zeinab; Harchegani, Mahboobeh Kiani

2016-01-15

Many different amendments, stabilizers, and conditioners are usually applied for soil and water conservation. Biochar is a carbon-enriched substance produced by thermal decomposition of organic material in the absence of oxygen with the goal to be used as a soil amendment. Biochar can be produced from a wide range of biomass sources including straw, wood, manure, and other organic wastes. Biochar has been demonstrated to restore soil fertility and crop production under many conditions, but less is known about the effects of its application on soil erosion and runoff control. Therefore, a rainfall simulation study, as a pioneer research, was conducted to evaluate the performance of the application of vinasse-produced biochar on the soil erosion control of a sandy clay loam soil packed in small-sized runoff 0.25-m(2) plots with 3 replicates. The treatments were (i) no biochar (control), (ii) biochar (8 tha(-1)) application at 24h before the rainfall simulation and (iii) biochar (8 tha(-1)) application at 48 h before the rainfall simulation. Rainfall was applied at 50 mm h(-1) for 15 min. The mean change of effectiveness in time to runoff could be found in biochar application at 24 and 48 h before simulation treatment with rate of +55.10% and +71.73%, respectively. In addition, the mean runoff volume 24 and 48 h before simulation treatments decreased by 98.46% and 46.39%, respectively. The least soil loss (1.12 ± 0.57 g) and sediment concentration (1.44 ± 0.48 gl(-1)) occurred in the biochar-amended soil treated 48 h before the rainfall simulation. In conclusion, the application of vinasse-produced biochar could effectively control runoff and soil loss. This study provided a new insight into the effects of biochar on runoff, soil loss, and sediment control due to water erosion in sandy clay loam soils. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of Metal Oxide Nanoparticles on Microbial Community Structure and Function in Two Different Soil Types

PubMed Central

Frenk, Sammy; Ben-Moshe, Tal; Dror, Ishai; Berkowitz, Brian; Minz, Dror

2013-01-01

Increased availability of nanoparticle-based products will, inevitably, expose the environment to these materials. Engineered nanoparticles (ENPs) may thus find their way into the soil environment via wastewater, dumpsters and other anthropogenic sources; metallic oxide nanoparticles comprise one group of ENPs that could potentially be hazardous for the environment. Because the soil bacterial community is a major service provider for the ecosystem and humankind, it is critical to study the effects of ENP exposure on soil bacteria. These effects were evaluated by measuring bacterial community activity, composition and size following exposure to copper oxide (CuO) and magnetite (Fe3O4) nanosized (<50 nm) particles. Two different soil types were examined: a sandy loam (Bet-Dagan) and a sandy clay loam (Yatir), under two ENP concentrations (1%, 0.1%). Results indicate that the bacterial community in Bet-Dagan soil was more susceptible to change due to exposure to these ENPs, relative to Yatir soil. More specifically, CuO had a strong effect on bacterial hydrolytic activity, oxidative potential, community composition and size in Bet-Dagan soil. Few effects were noted in the Yatir soil, although 1% CuO exposure did cause a significant decreased oxidative potential and changes to community composition. Fe3O4 changed the hydrolytic activity and bacterial community composition in Bet-Dagan soil but did not affect the Yatir soil bacterial community. Furthermore, in Bet-Dagan soil, abundance of bacteria annotated to OTUs from the Bacilli class decreased after addition of 0.1% CuO but increased with 1% CuO, while in Yatir soil their abundance was reduced with 1% CuO. Other important soil bacterial groups, including Rhizobiales and Sphingobacteriaceae, were negatively affected by CuO addition to soil. These results indicate that both ENPs are potentially harmful to soil environments. Furthermore, it is suggested that the clay fraction and organic matter in different soils interact with the ENPs and reduce their toxicity. PMID:24349575

Nitrous oxide emissions respond differently to mineral and organic nitrogen sources in contrasting soil types.

PubMed

Pelster, David E; Chantigny, Martin H; Rochette, Philippe; Angers, Denis A; Rieux, Christine; Vanasse, Anne

2012-01-01

The use of various animal manures for nitrogen (N) fertilization is often viewed as a viable replacement for mineral N fertilizers. However, the impacts of amendment type on NO production may vary. In this study, NO emissions were measured for 2 yr on two soil types with contrasting texture and carbon (C) content under a cool, humid climate. Treatments consisted of a no-N control, calcium ammonium nitrate, poultry manure, liquid cattle manure, or liquid swine manure. The N sources were surface applied and immediately incorporated at 90 kg N ha before seeding of spring wheat ( L.). Cumulative NO-N emissions from the silty clay ranged from 2.2 to 8.3 kg ha yr and were slightly lower in the control than in the fertilized plots ( = 0.067). The 2-yr mean NO emission factors ranged from 2.0 to 4.4% of added N, with no difference among N sources. Emissions of NO from the sandy loam soil ranged from 0.3 to 2.2 kg NO-N ha yr, with higher emissions with organic than mineral N sources ( = 0.015) and the greatest emissions with poultry manure ( < 0.001). The NO emission factor from plots amended with poultry manure was 1.8%, more than double that of the other treatments (0.3-0.9%), likely because of its high C content. On the silty clay, the yield-based NO emissions (g NO-N kg grain yield N) were similar between treatments, whereas on the sandy loam, they were greatest when amended with poultry manure. Our findings suggest that, compared with mineral N sources, manure application only increases soil NO flux in soils with low C content. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Influence of Root Exudates and Soil on Attachment of Pasteuria penetrans to Meloidogyne arenaria

PubMed Central

Liu, Chang; Ji, Pingsheng; Mekete, Tesfamariam; Joseph, Soumi

2017-01-01

The bacterium Pasteuria penetrans is a parasite of root-knot nematodes (Meloidogyne spp.). Endospores of P. penetrans attach to the cuticle of second-stage juveniles (J2) and subsequently sterilize infected females. When encumbered by large numbers of spores, juveniles are less mobile and their ability to infect roots is reduced. This study looked at different factors that influence spore attachment of P. penetrans to the root-knot nematode Meloidogyne arenaria. Pretreatment of J2 with root exudates of eggplant (Solanum melongena cv. Black beauty) reduced spore attachment compared with pretreatment with phosphate-buffered saline (PBS), suggesting that the nematode surface coat was altered or the spore recognition domains on the nematode surface were blocked. Spore attachment was equally reduced following exposure to root exudates from both host and nonhost plants for M. arenaria, indicating a common signal that affects spore attachment. Although phytohormones have been shown to influence the lipophilicity of the nematode surface coat, auxins and kinetins did not affect spore attachment compared with PBS. Root exudates reduced spore attachment more in sterilized soil than in natural soil. Sterilization may have eliminated microbes that consume root exudates, or altered the chemical components of the soil solution or root exudates. Root exudates caused a greater decrease in spore attachment in loamy sand than in a sandy loam soil. The sandy loam had higher clay content than the loamy sand, which may have resulted in more adsorption of compounds in the root exudates that affect spore attachment. The components of the root exudates could have also been modified by soil type. The results of this study demonstrate that root exudates can decrease the attachment of P. penetrans endospores to root-knot nematodes, indicating that when these nematodes enter the root zone their susceptibility to spore attachment may decrease. PMID:29062153

Influence of Root Exudates and Soil on Attachment of Pasteuria penetrans to Meloidogyne arenaria.

PubMed

Liu, Chang; Timper, Patricia; Ji, Pingsheng; Mekete, Tesfamariam; Joseph, Soumi

2017-09-01

The bacterium Pasteuria penetrans is a parasite of root-knot nematodes ( Meloidogyne spp.). Endospores of P. penetrans attach to the cuticle of second-stage juveniles (J2) and subsequently sterilize infected females. When encumbered by large numbers of spores, juveniles are less mobile and their ability to infect roots is reduced. This study looked at different factors that influence spore attachment of P. penetrans to the root-knot nematode Meloidogyne arenaria . Pretreatment of J2 with root exudates of eggplant ( Solanum melongena cv. Black beauty) reduced spore attachment compared with pretreatment with phosphate-buffered saline (PBS), suggesting that the nematode surface coat was altered or the spore recognition domains on the nematode surface were blocked. Spore attachment was equally reduced following exposure to root exudates from both host and nonhost plants for M. arenaria , indicating a common signal that affects spore attachment. Although phytohormones have been shown to influence the lipophilicity of the nematode surface coat, auxins and kinetins did not affect spore attachment compared with PBS. Root exudates reduced spore attachment more in sterilized soil than in natural soil. Sterilization may have eliminated microbes that consume root exudates, or altered the chemical components of the soil solution or root exudates. Root exudates caused a greater decrease in spore attachment in loamy sand than in a sandy loam soil. The sandy loam had higher clay content than the loamy sand, which may have resulted in more adsorption of compounds in the root exudates that affect spore attachment. The components of the root exudates could have also been modified by soil type. The results of this study demonstrate that root exudates can decrease the attachment of P. penetrans endospores to root-knot nematodes, indicating that when these nematodes enter the root zone their susceptibility to spore attachment may decrease.

Effects of fresh and aged biochars from pyrolysis and hydrothermal carbonization on nutrient sorption in agricultural soils

NASA Astrophysics Data System (ADS)

Gronwald, M.; Don, A.; Tiemeyer, B.; Helfrich, M.

2015-01-01

Leaching of nutrients from agricultural soils causes major environmental problems that may be reduced with biochar amendments to the soils. Biochars are characterised by a high adsorption capacity, i.e., they may retain nutrients such nitrate and ammonium. However, biochar properties strongly depend on feedstock and the production process. We investigated the nutrient retention capacity of biochars derived from pyrolysis (pyrochar) as well as from hydrothermal carbonization (hydrochar; produced at 200 and 250 °C) from three different feedstocks (digestates, Miscanthus, woodchips) mixed into different soil substrates (sandy loam and silty loam). Moreover, we investigated the influence of biochar degradation on its nutrient retention capacity using a seven-month in-situ field incubation of pyrochar and hydrochar. Pyrochars showed the highest ability to retain nitrate, ammonium and phosphate, with pyrochar from woodchips being particularly efficient in nitrate adsorption. Ammonium adsorption of pyrochars was controlled by the soil type of the soil-biochar mixture. We found some ammonium retention on sandy soils, but no pyrochar effect or even ammonium leaching from the loamy soil. The phosphate retention capacity of pyrochars strongly depended on the pyrochar feedstock with large phosphate leaching from digestate-derived pyrochar and some adsorption capacity from woodchip-derived pyrochar. Application of hydrochars to agricultural soils caused small, and often not significant, effects on nutrient retention. In contrast, some hydrochars did increase the leaching of nutrients compared to the non-amended control soil. We found a surprisingly rapid loss of the biochars' adsorption capacity after field application of the biochars. For all sites and for hydrochar and pyrochar, the adsorption capacity was reduced by 60-80% to less or no nitrate and ammonium adsorption. Thus, our results cast doubt on the efficiency of biochar applications to temperate zone soils to minimize nutrient losses via leaching.

Effects of fresh and aged chars from pyrolysis and hydrothermal carbonization on nutrient sorption in agricultural soils

NASA Astrophysics Data System (ADS)

Gronwald, M.; Don, A.; Tiemeyer, B.; Helfrich, M.

2015-06-01

Leaching of nutrients from agricultural soils causes major environmental problems that may be reduced with amendments of chars derived from pyrolysis (pyrochars) or hydrothermal carbonization (hydrochars). Chars are characterized by a high adsorption capacity - i.e. they may retain nutrients such as nitrate and ammonium. However, the physicochemical properties of the chars and hence their sorption capacity likely depend on feedstock and the production process. We investigated the nutrient retention capacity of pyrochars and hydrochars from three different feedstocks (digestates, Miscanthus, woodchips) mixed into different soil substrates (sandy loam and silty loam). Moreover, we investigated the influence of char degradation on its nutrient retention capacity using a 7-month in situ field incubation of pyrochar and hydrochar mixed into soils at three different field sites. Pyrochars showed the highest ability to retain nitrate, ammonium and phosphate, with pyrochar from woodchips being particularly efficient in nitrate adsorption. Ammonium adsorption of pyrochars was controlled by the soil type of the soil-char mixture. We found some ammonium retention on sandy soils, but no pyrochar effect or even ammonium leaching from the loamy soil. The phosphate retention capacity of pyrochars strongly depended on the pyrochar feedstock with large phosphate leaching from digestate-derived pyrochar and some adsorption capacity from woodchip-derived pyrochar. Application of hydrochars to agricultural soils caused small, and often not significant, effects on nutrient retention. In contrast, some hydrochars did increase the leaching of nutrients compared to the non-amended control soil. We found a surprisingly rapid loss of the chars' adsorption capacity after field application of the chars. For all sites and for hydrochar and pyrochar, the adsorption capacity was reduced by 60-80 % to less or no nitrate and ammonium adsorption. Thus, our results cast doubt on the efficiency of char applications to temperate zone soils to minimize nutrient losses via leaching.

Leaching of nitrogen and base cations from calcareous soil amended with organic residues.

PubMed

Zarabi, Mahboubeh; Jalali, Mohsen

2012-01-01

The potential for groundwater and surface water pollution by nutrients in organic residues, primarily nitrogen (N) and base cations (K+, Na+, Ca2+, Mg2+), is a consideration when applying such residues to land. In this study, we used a laboratory column leaching procedure to examine the leaching of N, K+, Na+, Ca2+ and Mg2+ in soils treated with two types of raw organic residues (poultry manure and potato residues) and one municipal waste compost, which are currently recycled on agricultural land in Iran. Each organic residue was thoroughly mixed with two different soils (sandy loam and clay) at the rate of 3%. Soil columns were leached at 4-d intervals for 92 d with distilled water, and effluents were analysed for pH, EC, nitrate (NO3(-)-N), ammonium (NH4(+)-N) K+, Na+, Ca2+ and Mg2+. The results indicated that the amounts of NO3(-)-N and NH4(+)-N leached from the poultry manure and potato residues could represent very important economic losses of N and pose an environmental threat under field conditions. The sandy loam soil amended with poultry manure lost the highest amount of NO3(-)-N (206.4 kg ha(-1)), and clay soil amended with poultry manure lost the highest amounts of NH4(+)-N (454.3 kg ha(-1)). The results showed that a treatment incorporating 3% of municipal waste compost could be used without negative effects to groundwater N concentration in clay soil. Significant amounts of K+, Na+, Ca2+, and Mg2+ were leached owing to the application of poultry manure, potato and municipal waste compost to soils. There was a positive relationship between K+, Na+, Ca2+, and Mg2+ with NO3(-)-N and NH4(+)-N leached in soils. Analysis of variance detected significant effects of amendment, soil type and time on the leaching NO3(-)-N, NH4(+)-N, K+, Na+, Ca2+ and Mg2+.

Soil seal development under simulated rainfall: Structural, physical and hydrological dynamics

NASA Astrophysics Data System (ADS)

Armenise, Elena; Simmons, Robert W.; Ahn, Sujung; Garbout, Amin; Doerr, Stefan H.; Mooney, Sacha J.; Sturrock, Craig J.; Ritz, Karl

2018-01-01

This study delivers new insights into rainfall-induced seal formation through a novel approach in the use of X-ray Computed Tomography (CT). Up to now seal and crust thickness have been directly quantified mainly through visual examination of sealed/crusted surfaces, and there has been no quantitative method to estimate this important property. X-ray CT images were quantitatively analysed to derive formal measures of seal and crust thickness. A factorial experiment was established in the laboratory using open-topped microcosms packed with soil. The factors investigated were soil type (three soils: silty clay loam - ZCL, sandy silt loam - SZL, sandy loam - SL) and rainfall duration (2-14 min). Surface seal formation was induced by applying artificial rainfall events, characterised by variable duration, but constant kinetic energy, intensity, and raindrop size distribution. Soil porosities derived from CT scans were used to quantify the thickness of the rainfall-induced surface seals and reveal temporal seal micro-morphological variations with increasing rainfall duration. In addition, the water repellency and infiltration dynamics of the developing seals were investigated by measuring water drop penetration time (WDPT) and unsaturated hydraulic conductivity (Kun). The range of seal thicknesses detected varied from 0.6 to 5.4 mm. Soil textural characteristics and OM content played a central role in the development of rainfall-induced seals, with coarser soil particles and lower OM content resulting in thicker seals. Two different trends in soil porosity vs. depth were identified: i) for SL soil porosity was lowest at the immediate soil surface, it then increased constantly with depth till the median porosity of undisturbed soil was equalled; ii) for ZCL and SL the highest reduction in porosity, as compared to the median porosity of undisturbed soil, was observed in a well-defined zone of maximum porosity reduction c. 0.24-0.48 mm below the soil surface. This contrasting behaviour was related to different dynamics and processes of seal formation which depended on the soil properties. The impact of rainfall-induced surface sealing on the hydrological behaviour of soil (as represented by WDTP and Kun) was rapid and substantial: an average 60% reduction in Kun occurred for all soils between 2 and 9 min rainfall, and water repellent surfaces were identified for SZL and ZCL. This highlights that the condition of the immediate surface of agricultural soils involving rainfall-induced structural seals has a strong impact in the overall ability of soil to function as water reservoir.

An Emerging Wine Region in Nova Scotia, Canada: Terroir Trials and Tribulations

NASA Astrophysics Data System (ADS)

Cameron, B. I.; Ketter, B. S.; Karakis, S.

2012-12-01

Nova Scotia, strategically located on Canada's east coast, is an emerging wine region, whose distinctive wines are garnering international acclaim. Nova Scotia has a long and rich tradition of growing grapes for wine dating back as far as 1611. Nova Scotia's mesoclimates, glacial soils, and proximity to the Atlantic Ocean form a complex alliance to create a unique and expressive terroir. Tidal Bay is a new appellation wine for Nova Scotia stylistically defined as a fresh, crisp and high-acid blend of white grapes. There are four main wine-growing regions in Nova Scotia, all influenced by the warming effects of the Bay of Fundy and Atlantic Ocean: Malagash Peninsula, Annapolis Valley, Bear River Valley and the South Shore. Nova Scotia currently has 14 producing wineries with many more in the development stage. Nova Scotia grape growers not only have had success developing mature and consistent hybrids, but in recent years several vinifera have flourished in this cool climate area. The white hybrids include L'Acadie Blanc, New York Muscat, Seyval Blanc, and Vidal Blanc. The white vinifera include chardonnay, riesling, pinot gris, and sauvignon blanc. Red hybrids are Baco Noir, Leon Millet, Lucie Kuhlmann, and Marechal Foch, whereas the only red vinifera is pinot noir. Nova Scotia has nearly perfect climatic conditions for making world class icewines and sparkling wines. A preliminary GIS analysis of climate, topographic, geology and soil data helps to define Nova Scotia's terroir. Annual precipiatation varies from 10 to 21.6 cm/year with a vast majority of the wineries located in regions with the lowest rainfall. Daily average temperature ranges from 5.5 to 7.5°C, degree growing days above 5°C from 1382 to 1991, and mean August temperature from 15.6 to 19.3 °C. Wineries cluster in the warmest regions based on these temperature measures to assist grape ripening. Soils in these diverse wine regions can range from silty, sandy and clay loams to more gravel-rich sandy loams. In the Gaspereaux Valley, a sub-valley of the Annapolis Valley, relatively fertile silty and clay loams dominate on the south-facing slope, but well-drained, gravel-rich glacial soils on the north-facing slope impart a complex and mineral flavor profile to the wines. Detailed soil profiles from select vineyards along with studies of soil texture and chemistry highlight differences in terroirs in the four wine regions. This terroir study assists the expanding, but young wine industry in Nova Scotia to ideally match grape variety to vineyard block.

Arsenic and Heavy Metal Contamination in Soils under Different Land Use in an Estuary in Northern Vietnam

PubMed Central

Nguyen Van, Thinh; Ozaki, Akinori; Nguyen Tho, Hoang; Nguyen Duc, Anh; Tran Thi, Yen; Kurosawa, Kiyoshi

2016-01-01

Heavy metal contamination of soil and sediment in estuaries warrants study because a healthy estuarine environment, including healthy soil, is important in order to achieve ecological balance and good aquaculture production. The Ba Lat estuary of the Red River is the largest estuary in northern Vietnam and is employed in various land uses. However, the heavy metal contamination of its soil has not yet been reported. The following research was conducted to clarify contamination levels, supply sources, and the effect of land use on heavy metal concentrations in the estuary. Soil samples were collected from the top soil layer of the estuary, and their arsenic (As), chromium (Cr), cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) concentrations were analyzed, as were other soil properties. Most soils in the estuary were loam, silt loam, or sandy loam. The pH was neutral, and the cation exchange capacity ranged from 3.8 to 20 cmol·kg−1. Manganese and iron concentrations averaged 811 µg·g−1 and 1.79%, respectively. The magnitude of the soil heavy metal concentrations decreased in the order of Zn > Pb > Cr > Cu > As > Cd. The concentrations were higher in the riverbed and mangrove forest than in other land-use areas. Except for As, the mean heavy metal concentrations were lower than the permissible levels for agricultural soils in Vietnam. The principal component analyses suggested that soil As, Pb, Zn, Cd, and Cu were of anthropogenic origin, whereas Cr was of non-anthropogenic origin. The spatial distribution of concentration with land use indicated that mangrove forests play an important role in preventing the spread of heavy metals to other land uses and in maintaining the estuarine environment. PMID:27827965

Arsenic and Heavy Metal Contamination in Soils under Different Land Use in an Estuary in Northern Vietnam.

PubMed

Nguyen Van, Thinh; Ozaki, Akinori; Nguyen Tho, Hoang; Nguyen Duc, Anh; Tran Thi, Yen; Kurosawa, Kiyoshi

2016-11-05

Heavy metal contamination of soil and sediment in estuaries warrants study because a healthy estuarine environment, including healthy soil, is important in order to achieve ecological balance and good aquaculture production. The Ba Lat estuary of the Red River is the largest estuary in northern Vietnam and is employed in various land uses. However, the heavy metal contamination of its soil has not yet been reported. The following research was conducted to clarify contamination levels, supply sources, and the effect of land use on heavy metal concentrations in the estuary. Soil samples were collected from the top soil layer of the estuary, and their arsenic (As), chromium (Cr), cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) concentrations were analyzed, as were other soil properties. Most soils in the estuary were loam, silt loam, or sandy loam. The pH was neutral, and the cation exchange capacity ranged from 3.8 to 20 cmol·kg -1 . Manganese and iron concentrations averaged 811 µg·g -1 and 1.79%, respectively. The magnitude of the soil heavy metal concentrations decreased in the order of Zn > Pb > Cr > Cu > As > Cd. The concentrations were higher in the riverbed and mangrove forest than in other land-use areas. Except for As, the mean heavy metal concentrations were lower than the permissible levels for agricultural soils in Vietnam. The principal component analyses suggested that soil As, Pb, Zn, Cd, and Cu were of anthropogenic origin, whereas Cr was of non-anthropogenic origin. The spatial distribution of concentration with land use indicated that mangrove forests play an important role in preventing the spread of heavy metals to other land uses and in maintaining the estuarine environment.

Effects of soil texture and drought stress on the uptake of antibiotics and the internalization of Salmonella in lettuce following wastewater irrigation.

PubMed

Zhang, Yuping; Sallach, J Brett; Hodges, Laurie; Snow, Daniel D; Bartelt-Hunt, Shannon L; Eskridge, Kent M; Li, Xu

2016-01-01

Treated wastewater is expected to be increasingly used as an alternative source of irrigation water in areas facing fresh water scarcity. Understanding the behaviors of contaminants from wastewater in soil and plants following irrigation is critical to assess and manage the risks associated with wastewater irrigation. The objective of this study was to evaluate the effects of soil texture and drought stress on the uptake of antibiotics and the internalization of human pathogens into lettuce through root uptake following wastewater irrigation. Lettuce grown in three soils with variability in soil texture (loam, sandy loam, and sand) and under different levels of water stress (no drought control, mild drought, and severe drought) were irrigated with synthetic wastewater containing three antibiotics (sulfamethoxazole, lincomycin and oxytetracycline) and one Salmonella strain a single time prior to harvest. Antibiotic uptake in lettuce was compound-specific and generally low. Only sulfamethoxazole was detected in lettuce with increasing uptake corresponding to increasing sand content in soil. Increased drought stress resulted in increased uptake of lincomycin and decreased uptake of oxytetracycline and sulfamethoxazole. The internalization of Salmonella was highly dependent on the concentration of the pathogen in irrigation water. Irrigation water containing 5 Log CFU/mL Salmonella resulted in limited incidence of internalization. When irrigation water contained 8 Log CFU/mL Salmonella, the internalization frequency was significantly higher in lettuce grown in sand than in loam (p = 0.009), and was significantly higher in lettuce exposed to severe drought than in unstressed lettuce (p = 0.049). This work demonstrated how environmental factors affected the risk of contaminant uptake by food crops following wastewater irrigation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Are we sinking Sandy Hook? Possible impacts of groundwater extraction to sea-level change

NASA Astrophysics Data System (ADS)

Johnson, C. S.; Fan, Y.; Miller, K. G.; Browning, J. V.

2017-12-01

The tide gauge at Sandy Hook, NJ, a spit of sand extending 8 km into Raritan Bay of New York and New Jersey, recorded a 20th century rate of relative sea-level (RSL) rise of 4.0±0.5 mm/yr, significantly higher than the 1.4±0.2 mm/yr rate of global mean sea-level rise for the twentieth century. The Battery, NY tide gauge, located atop crystalline bedrock 26 km to the northwest, recorded a 20th century rate of RSL rise of 3.0±0.3 mm/yr and reflects the regional rate of RSL rise. After global and regional effects are removed from the rate of RSL rise at Sandy Hook, the remaining 0.9±0.5 mm/yr is due to local effects, autocompaction and groundwater extraction induced compaction, within the unconsolidated Cretaceous to recent sediments underlying Sandy Hook. Our previous work showed that 0.13 mm/yr (90% CI 0.01-0.34 mm/yr) is due to autocompaction of young (≤13,350 cal yrs BP), highly compressible, Quaternary sediments underlying Sandy Hook. The remaining 0.8 mm/yr (90% CI 0.3-1.2 mm/yr) is hypothesized to be due to regional and local groundwater extraction. Previous studies have shown that Sandy Hook is within the cone of depression for Monmouth County, NJ. Historical records indicate that pumping for Ft. Hancock, a military installation on Sandy Hook, depleted some shallow aquifers as early as 1905. Visual MODFLOW was used to model the northern portion of the New Jersey coastal plain. Well logs from the northern New Jersey coastal plain were compiled and interpreted to refine subsurface geometries and build the model grid. Well permits provided modern locations and rates of groundwater extraction. 1,794 observation wells were used to calibrate the model. We present model results simulating the change in regional and local groundwater flow and hydraulic pressures from pre-development ( 1880) to present. The pressure changes were then used to calculate the potential changes in thickness of each of the stratigraphic units underneath Sandy Hook between 1880 and present. The resulting average rate of groundwater extraction induced compaction is between 0.2 and 4.3 mm/yr. Better constraints on stratigraphy, pumping rates, and improved model boundaries are being used to narrow this range.

Relationships between soil moisture-holding properties and soil texture, organic matter content, and bulk density

NASA Technical Reports Server (NTRS)

Riley, H. C. F.

1981-01-01

Specimens from the surface horizon and the subsoil of 62 soil horizons in Hedmark and Oppland were investigated to study how the mechanical composition of the soil, the organic matter content and the bulk density affect their porosity and air capacity and their total and available water content. Most of the specimens belonged to the loam group, and a smaller number was from sandy and silty types of soil. Equations were established to make it possible to calculate the water retention curves and the amount of available water from the above mentioned parameters. As a rule, errors derived from the equations are no greater than those which are found in similar research in other countries.

Automated Microbial Metabolism Laboratory

NASA Technical Reports Server (NTRS)

1971-01-01

The effect of several environmental parameters on previously developed life detection systems is explored. Initial attempts were made to conduct all the experiments in a moist mode (high soil volume to water volume ratio). However, only labeled release and measurement of ATP were found to be feasible under conditions of low moisture. Therefore, these two life detection experiments were used for most of the environmental effects studies. Three soils, Mojave (California desert), Wyaconda (Maryland, sandy loam) and Victoria Valley (Antarctic desert) were generally used throughout. The environmental conditions studied included: incubation temperature 3 C to 80 C, ultraviolet irradiation of soils, variations in soil/liquid ratio, specific atmospheric gases, various antimetabolites, specific substrates, and variation in pH. An experiment designed to monitor nitrogen metabolism was also investigated.

Biological monitoring of an agricultural food chain: soil cadmium and lead in ruminant tissues

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

Brams, E.; Anthony, W.; Weatherspoon, L.

1988-01-01

The hypothesis that low-level contamination of a sandy loam soil with cadmium and lead at 0.01-9.0 and 3.0-54.0 ug g-1 soil respectively could induce a response in grasses as measured by the accumulation of soil Cd and Pb in sudan sorghum hay, was verified at the 0.08 and 0.05 levels respectively. Employing these data and the concentrations of Cd and Pb in blood, liver, kidney, select brain tissues and fetal tissues of pregnant goats as test animals consuming the hay over a 98 day feeding period, an assessment of the magnitude of these metals retained along select pathways of themore » agricultural food chain was developed.« less

Adhesion of and to soil in runoff as influenced by polyacrylamide.

PubMed

Bech, Tina B; Sbodio, Adrian; Jacobsen, Carsten S; Suslow, Trevor

2014-11-01

Polyacrylamide (PAM) is used in agriculture to reduce soil erosion and has been reported to reduce turbidity, nutrients, and pollutants in surface runoff water. The objective of this work was to determine the effect of PAM on the concentration of enteric bacteria in surface runoff by comparing four enteric bacteria representing phenotypically different motility and hydrophobicity from three soils. Results demonstrated that bacterial surface runoff was differentially influenced by the PAM treatment. Polyacrylamide treatment increased surface runoff for adhered and planktonic cells from a clay soil; significantly decreased surface runoff of adhered bacteria, while no difference was observed for planktonic bacteria from the sandy loam; and significantly decreased the surface runoff of planktonic cells, while no difference was observed for adhered bacteria from the clay loam. Comparing strains from a final water sample collected after 48 h showed a greater loss of while serovar Poona was almost not detected. Thus, (i) the PAM efficiency in reducing the concentration of enteric bacteria in surface runoff was influenced by soil type and (ii) variation in the loss of enteric bacteria highlights the importance of strain-specific properties that may not be captured with general fecal indicator bacteria. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Preimpoundment water quality of Raystown Branch Juniata River and six tributary streams, south-central Pennsylvania

USGS Publications Warehouse

Williams, Donald R.

1976-01-01

The Raystown Branch Juniata River watershed, which is the main water source for Raystown Lake, is a 960-square-mile (2,490 square kilometres) drainage basin in south-central Pennsylvania. Preimpoundment water-quality data were collected on the Raystown Branch and six tributary st.reams in the basin. Specific conductance values varied inversely with water discharge. The pH values were extremely low only at the Shoup Run site. Dissolved oxygen concentrations observed at all sites indicated a relatively high oxygen saturation level throughout the year. Seasonal variations in nitrate-N and orthophosphate-P levels were measured at the main inflow station at Saxton, Pa. The highest concentrations of nitrate-N and orthophosphate-P occurred in the winter and spring months and the lowest concentrations were measured dur:l.ng the swnmer and fall. Bacteriological data indicated no excessive -amounts of fecal matter present at the inflows. Soil samples collected at four sites in the impoundment area were predominantly of the Barbour, Philo, and Basher series, which are considered to be highly fertile soils with silt-loam and sandy~loam textures. Morphological features of the lake basin and low nutrient levels at the inflows should prevent excessive weed growth around the lake perimeter.

Response of Soybean to Heterodera glycines Races 1 and 2 in Different Soil Types.

PubMed

Schmitt, D P; Ferris, H; Barker, K R

1987-04-01

Experiments were conducted for 3 years at four locations and 1 year with six soil types at a common location in North Carolina to determine damage and control-cost functions for Heterodera glycines races 1 and 2 on soybean. In the experiments on native loamy sand and sandy soils, tolerance limits for initial population densities were 0 or very low, whereas in a muck, the tolerance limit was 315 eggs/500 cm(3) soil. The aggressive race 2 was more damaging than race 1 in Lakeland sand and Norfolk loamy sand. The crop response was not different between races in the Appling sandy clay loam and Belhaven muck. Soybean yield responses to H. glycines were linear in six soil types in microplots at a common site. The amount of damage varied among these soil types, with lowest yields in the muck because of severe drought stress in this soil. An exponential function adequately described soybean yield response relative to nematode control with increasing rates of aldicarb in Norfolk loamy sand. Treatment with aldicarb in the Lakeland sand decreased the effective egg population of H. glycines but had only a minor effect in the muck.

Sensitivity analysis and metamodeling of a toolchain of models to help sizing vetetative filter strips in a watershed.

NASA Astrophysics Data System (ADS)

Lauvernet, Claire; Noll, Dorothea; Muñoz-Carpena, Rafael; Carluer, Nadia

2014-05-01

In Europe, environmental agencies do the finding a significant presence of contaminants in surface water, which is partly due to pesticide applications. Vegetative filter strips (VFS), often located along rivers, are a common tool among other buffer zones to reduce non point source pollution of water by reducing surface runoff. However, they need to be adapted to the agro-pedo-climatic conditions, both in terms of position and size, in order to be efficient. This is one of the roles of TOPPS-PROWADIS project which involves European experts and stakeholders to develop and recommend Best Management Practices (BMPs) to reduce pesticide transfer by drift or runoff in several European countries. In this context, Irstea developed a guide accompanying the use of different tools, which allows designing VFS by simulating their efficiency to limit transfers. It needs the user to define both a scenario of incoming surface runoff and the buffer zone characteristics. First, the contributive zone (surface, length, slope) is derived from the topography by a GIS tool, HydroDem. ; 2nd, the runoff hydrograph coming in the buffer zone is generated from a rainfall hyetogram typical of the area, using Curve Number theory, taking into account soil characteristics. The VFS's optimal width is then deduced for a given desired efficiency (for example 70% of runoff reduction), by using VFSMOD model, which simulates water, suspended matters (and pesticides) transfer inside a vegetative filter strip. Results also indicate if this kind of buffer zone is relevant in that situation (if too high, another type of buffer zone may be more relevant, for example constructed wetland). This method assumes that the user supplies quite a lot of field knowledge and data, which are not always easily available. In order to fill in the lack of real data, a set of virtual scenarios was tested, which is supposed to cover a large range of agro-pedo-climatic conditions in Europe, considering both the upslope agricultural field and the VFS characteristics. These scenarios are based on: 2 types of climates (North and South-west of France), different rainfall intensities and durations, different lengths and slopes of hillslope, different humidity conditions, 4 soil types (silt loam, sandy loam, clay loam, sandy clay loam), 2 crops (wheat and corn) for the contributive area, 2 water table depths (1m and 2.5m) and 4 soil types for the VFS. The sizing method was applied for all these scenarios, and a sensitivity analysis of the VFS optimal length was performed for all the input parameters in order to understand their influence, and to identify for which a special care has to be given. Based on that sensitivity analysis, a metamodel has been developed. The idea is to simplify the whole toolchain and to make it possible to perform the buffer sizing by using a unique tool and a smaller set of parameters, given the available information from the end users. We first compared several mathematical methods to compute the metamodel, and then validated them on an agricultural watershed with real data in the North-West of France.

Determination of soil degradation in argentine semi-arid environments from remote sensors: case department of patagones, province of buenos aires

NASA Astrophysics Data System (ADS)

Pezzola, Alejandro; Cacella, Alejandra; Enrique, Mario; Winschel, Cristina

2017-04-01

The continental territory of the Argentine Republic owns 75% of its surface under arid and semiarid conditions to the west of the meridian of 64°. Wind erosion is the main physical cause of desertification. In the Pampena area, studies showed that the sandy loam soils were more pronounced than the sandy loam with significant losses of organic matter, decreases in the cation exchange capacity and modification of the mineral composition of the very fine sand fraction (From 73 to 100 μm), with increases in the proportion of heavy minerals (magnetite) relative to light (quartz). In the Patagones department, Buenos Aires province, the soils with a sandy-loamy texture, which are transported by wind and deposited on calcium carbonate (tosca), with little moisture retention and susceptible to wind erosion. In the 1980s and 1990s, increases in rainfall above the historical average led to a shift of the isohytes towards the southwest, leading to agricultural intensification that caused greater pressure on the soil and native vegetation. This advance on the native vegetation within the Patagones produced a reduction between 1975 and 2009 of 432,280 ha, leaving only 31% of the area covered by native forest - shrub xerophyte today. Between 2005-2009, the call "agricultural drought" caused losses in crops, wheat - oats and natural pastures associated with the native forest, causing a significant deterioration of the soil, exposing them to wind erosion. Remote sensors represent a very valuable technology for the mapping and evaluation of soil erosion. The availability of multispectral images allows the mapping and monitoring of changes in the dynamics of the erosion process. The objective of this work was to make an expeditious diagnosis of the surface affected by wind erosion and to evaluate the degree to which the soils destined for agriculture and livestock were affected. For this purpose, Terra's MODIS (Moderate-Resolution Imaging Spectroradiometer) sensor information was used with a temporal resolution of 1 to 2 days, 36 spectral bands, spatial resolution of 250m and Improved Vegetation Index (EVI). The period was covered from July 2007 to July 2009 by analyzing 47 images of the EVI product. The phenological curves of the soil cover were obtained. Of 1,360,717 ha it was estimated that there are a total of 393,511 hectares of eroded soils: 47,337 ha from mild to moderate, 219,204 ha moderate to severe and 126,970 ha severe to severe

Investigation of the effects of pile jetting and performing

DOT National Transportation Integrated Search

1999-07-01

This report presents the results of an experimental study performed with similar model piles installed using (1) impact driving (2) jetting and (3) performing in a sandy soil (with 10% clay) compacted to different unit weights under saturated and uns...

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...

Simultaneous hyperaccumulation of multiple heavy metals by Helianthus annuus grown in a contaminated sandy-loam soil.

PubMed

Cutright, Teresa; Gunda, Nagaraju; Kurt, Firat

2010-08-01

Phytoremediation is a promising means for the treatment of contamination arising from heavy metal spills. Although several species have been identified as hyperaccumulators, most of the studies were performed with only one heavy metal. Experiments were conducted with two cultivars of H. annuus exposed to different combinations of metal contamination (30 mg/kg Cd, Cr, Ni, As, and/or Fe). Cultivar efficiency was based on total metal uptake, as well as translocation and selectivity of each metal. The results for each cultivar were also compared after 0.1 g/kg or 0.3 g/kg EDTA was added to enhance metal bioavailability. The key finding was that H. annuus achieved hyperaccumulator status for multiple metals simultaneously: Cd, Cr, and As.

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.

Features of Scots pine radial growth in conditions of provenance trial.

NASA Astrophysics Data System (ADS)

Kuzmin, Sergey; Kuzmina, Nina

2013-04-01

Provenance trial of Scots pine in Boguchany forestry of Krasnoyarsk krai is conducted on two different soils - dark-grey loam forest soil and sod-podzol sandy soil. Complex of negative factors for plant growth and development appears in dry conditions of sandy soil. It could results in decrease of resistance to diseases. Sandy soils in different climatic zones have such common traits as low absorbing capacity, poorness of elemental nutrition, low microbiological activity and moisture capacity, very high water permeability. But Scots pine trees growing in such conditions could have certain advantages and perspectives of use. In the scope of climate change (global warming) the study of Scots pine growth on sandy soil become urgent because of more frequent appearance of dry seasons. Purpose of the work is revelation of radial growth features of Scots pine with different origin in dry conditions of sandy soil and assessment of external factors influence. The main feature of radial growth of majority of studied pine provenances in conditions of sandy soil is presence of significant variation of increment with distinct decline in 25-years old with loss of tree rings in a number of cases. The reason of it is complex of factors: deficit of June precipitation and next following outbreak of fungal disease. Found «frost rings» for all trees of studied clymatypes in 1992 are the consequence of temperature decline from May 21 to June 2 - from 23 down to 2 degree Celsius. Perspective climatypes with biggest radial increments and least sensitivity to fungal disease were revealed. Eniseysk and Vikhorevka (from Krasnoyarsk krai and Irkutsk oblast)provenances of pine have the biggest radial increments, the least sensitivity to Cenangium dieback and smallest increments decline. These climatypes are in the group of perspective provenances and in present time they are recommended for wide trial in the region for future use in plantation forest growing. Kandalaksha (Murmansk oblast) climatype from northern taiga with good resistance to pathogen have nonsignificant decline in radial increment during epiphytoty in comparison with local and southern climatypes. Southern Chemal provenance (Altai) after influence of Cenangium dieback has more than others losses of tree rings as the result of nonresistance to this fungal disease.

Changes of soil particle size distribution in tidal flats in the Yellow River Delta.

PubMed

Lyu, Xiaofei; Yu, Junbao; Zhou, Mo; Ma, Bin; Wang, Guangmei; Zhan, Chao; Han, Guangxuan; Guan, Bo; Wu, Huifeng; Li, Yunzhao; Wang, De

2015-01-01

The tidal flat is one of the important components of coastal wetland systems in the Yellow River Delta (YRD). It can stabilize shorelines and protect coastal biodiversity. The erosion risk in tidal flats in coastal wetlands was seldom been studied. Characterizing changes of soil particle size distribution (PSD) is an important way to quantity soil erosion in tidal flats. Based on the fractal scale theory and network analysis, we determined the fractal characterizations (singular fractal dimension and multifractal dimension) soil PSD in a successional series of tidal flats in a coastal wetland in the YRD in eastern China. The results showed that the major soil texture was from silt loam to sandy loam. The values of fractal dimensions, ranging from 2.35 to 2.55, decreased from the low tidal flat to the high tidal flat. We also found that the percent of particles with size ranging between 0.4 and 126 μm was related with fractal dimensions. Tide played a great effort on soil PSD than vegetation by increasing soil organic matter (SOM) content and salinity in the coastal wetland in the YRD. Tidal flats in coastal wetlands in the YRD, especially low tidal flats, are facing the risk of soil erosion. This study will be essential to provide a firm basis for the coast erosion control and assessment, as well as wetland ecosystem restoration.

Impact of paper mill wastewater on soil properties and crop yield through lysimeter studies.

PubMed

Singh, P K; Ladwani, K; Ladwani, K; Deshbhratar, P B; Ramteke, D S

2013-01-01

Paper and pulp industries produce large quantities of wastewater which can have adverse effects on the receiving water systems. In the present study lysimeters were used and filled with different soils replicating natural soil horizons and provided with a leachate collection system. The physico-chemical characteristics of the soil in each lysimeter and the quality of wastewater before leaching were assessed. Treated wastewater was evaluated for crop irrigation, and was categorized according to the irrigation water class 'Increasing Problem to Severe Problem' with respect to salinity and specific ion toxicity. Sandy loam soils showed 96% chemical oxygen demand (COD) removal while clay loam soils removed 99% of COD, and the colour removal in both the cases was found to be 100%. Application of wastewater resulted in an increase of pH value, ranging from 6.2-7.6; the electrical conductivity (ECe) of saturated extracts was found to be 0.6-1.7 dS m(-1), and exchangeable sodium percentage (ESP) ranged from 7.8-11.1% in soils. Similarly, an increase in the organic carbon, available nitrogen, phosphorus and potash content of soils was observed when irrigated with wastewater. Wastewater irrigation showed increased grain and straw yield of jowar, wheat and moong. These results permit successful utilization of pulp and paper mill wastewater for crop production without damaging the soils.

Rainfall-Induced Release of Fecal Coliforms and Other Manure Constituents: Comparison and Modeling▿

PubMed Central

Guber, A. K.; Shelton, D. R.; Pachepsky, Y. A.; Sadeghi, A. M.; Sikora, L. J.

2006-01-01

Modeling release of fecal coliforms is an important component of fate and transport simulations related to environmental water quality. Manure constituents other than fecal coliforms may serve as natural tracers of fecal contamination provided that their release from manure to runoff is similar to the fecal coliform release. The objectives of this work were to compare release of fecal coliforms (FC), chloride (Cl−), organic carbon (OC), and water-soluble phosphorus (P) from dissolving manure and to assess the performance of three models in describing the observed release. Bovine manure was applied on 0.5- by 0.3-m bare and vegetated subplots with 20% slope on sandy loam and clay loam soils. Concentrations of Cl−, FC, OC, and P were measured in runoff collected from troughs at the edges of the subplots at 5-min intervals during 1-h rainfall simulations. The one-parametric exponential model and two-parametric Vadas-Kleinman-Sharpley model and Bradford-Schijven model were fitted to the data. The Bradford-Schijven model had uncorrelated parameters, one of which was linearly related to the irrigation rate, and another parameter reflected the presence or the absence of vegetation. Kinetics of the FC release from manure was similar to the release kinetics of P and OC. The Bradford-Schijven model is recommended to simulate the release of manure constituents. PMID:17028232

Root hairs aid soil penetration by anchoring the root surface to pore walls

PubMed Central

Bengough, A. Glyn; Loades, Kenneth; McKenzie, Blair M.

2016-01-01

The physical role of root hairs in anchoring the root tip during soil penetration was examined. Experiments using a hairless maize mutant (Zea mays: rth3–3) and its wild-type counterpart measured the anchorage force between the primary root of maize and the soil to determine whether root hairs enabled seedling roots in artificial biopores to penetrate sandy loam soil (dry bulk density 1.0–1.5g cm−3). Time-lapse imaging was used to analyse root and seedling displacements in soil adjacent to a transparent Perspex interface. Peak anchorage forces were up to five times greater (2.5N cf. 0.5N) for wild-type roots than for hairless mutants in 1.2g cm−3 soil. Root hair anchorage enabled better soil penetration for 1.0 or 1.2g cm−3 soil, but there was no significant advantage of root hairs in the densest soil (1.5g cm−3). The anchorage force was insufficient to allow root penetration of the denser soil, probably because of less root hair penetration into pore walls and, consequently, poorer adhesion between the root hairs and the pore walls. Hairless seedlings took 33h to anchor themselves compared with 16h for wild-type roots in 1.2g cm−3 soil. Caryopses were often pushed several millimetres out of the soil before the roots became anchored and hairless roots often never became anchored securely.The physical role of root hairs in anchoring the root tip may be important in loose seed beds above more compact soil layers and may also assist root tips to emerge from biopores and penetrate the bulk soil. PMID:26798027

Root hairs aid soil penetration by anchoring the root surface to pore walls.

PubMed

Bengough, A Glyn; Loades, Kenneth; McKenzie, Blair M

2016-02-01

The physical role of root hairs in anchoring the root tip during soil penetration was examined. Experiments using a hairless maize mutant (Zea mays: rth3-3) and its wild-type counterpart measured the anchorage force between the primary root of maize and the soil to determine whether root hairs enabled seedling roots in artificial biopores to penetrate sandy loam soil (dry bulk density 1.0-1.5g cm(-3)). Time-lapse imaging was used to analyse root and seedling displacements in soil adjacent to a transparent Perspex interface. Peak anchorage forces were up to five times greater (2.5N cf. 0.5N) for wild-type roots than for hairless mutants in 1.2g cm(-3) soil. Root hair anchorage enabled better soil penetration for 1.0 or 1.2g cm(-3) soil, but there was no significant advantage of root hairs in the densest soil (1.5g cm(-3)). The anchorage force was insufficient to allow root penetration of the denser soil, probably because of less root hair penetration into pore walls and, consequently, poorer adhesion between the root hairs and the pore walls. Hairless seedlings took 33h to anchor themselves compared with 16h for wild-type roots in 1.2g cm(-3) soil. Caryopses were often pushed several millimetres out of the soil before the roots became anchored and hairless roots often never became anchored securely.The physical role of root hairs in anchoring the root tip may be important in loose seed beds above more compact soil layers and may also assist root tips to emerge from biopores and penetrate the bulk soil. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Comparison of model microbial allocation parameters in soils of varying texture

NASA Astrophysics Data System (ADS)

Hagerty, S. B.; Slessarev, E.; Schimel, J.

2017-12-01

The soil microbial community decomposes the majority of carbon (C) inputs to the soil. However, not all of this C is respired—rather, a substantial portion of the carbon processed by microbes may remain stored in the soil. The balance between C storage and respiration is controlled by microbial turnover rates and C allocation strategies. These microbial community properties may depend on soil texture, which has the potential to influence both the nature and the fate of microbial necromass and extracellular products. To evaluate the role of texture on microbial turnover and C allocation, we sampled four soils from the University of California's Hastings Reserve that varied in texture (one silt loam, two sandy loam, and on clay soil), but support similar grassland plant communities. We added 14C- glucose to the soil and measured the concentration of the label in the carbon dioxide (CO2), microbial biomass, and extractable C pools over 7 weeks. The labeled biomass turned over the slowest in the clay soil; the concentration of labeled biomass was more than 1.5 times the concentration of the other soils after 8 weeks. The clay soil also had the lowest mineralization rate of the label, and mineralization slowed after two weeks. In contrast, in the sandier soils mineralization rates were higher and did not plateau until 5 weeks into the incubation period. We fit the 14C data to a microbial allocation model and estimated microbial parameters; assimilation efficiency, exudation, and biomass specific respiration and turnover for each soil. We compare these parameters across the soil texture gradient to assess the extent to which models may need to account for variability in microbial C allocation across soils of different texture. Our results suggest that microbial C turns over more slowly in high-clay soils than in sandy soils, and that C lost from microbial biomass is retained at higher rates in high-clay soils. Accounting for these differences in microbial allocation and carbon stabilization could improve model representations of C cycling across a range of soil types.

Impacts of crop rotations on soil organic carbon sequestration

NASA Astrophysics Data System (ADS)

Gobin, Anne; Vos, Johan; Joris, Ingeborg; Van De Vreken, Philippe

2013-04-01

Agricultural land use and crop rotations can greatly affect the amount of carbon sequestered in the soil. We developed a framework for modelling the impacts of crop rotations on soil carbon sequestration at the field scale with test case Flanders. A crop rotation geo-database was constructed covering 10 years of crop rotation in Flanders using the IACS parcel registration (Integrated Administration and Control System) to elicit the most common crop rotation on major soil types in Flanders. In order to simulate the impact of crop cover on carbon sequestration, the Roth-C model was adapted to Flanders' environment and coupled to common crop rotations extracted from the IACS geodatabases and statistical databases on crop yield. Crop allometric models were used to calculate crop residues from common crops in Flanders and subsequently derive stable organic matter fluxes to the soil (REGSOM). The REGSOM model was coupled to Roth-C model was run for 30 years and for all combinations of seven main arable crops, two common catch crops and two common dosages of organic manure. The common crops are winter wheat, winter barley, sugar beet, potato, grain maize, silage maize and winter rapeseed; the catch crops are yellow mustard and Italian ryegrass; the manure dosages are 35 ton/ha cattle slurry and 22 ton/ha pig slurry. Four common soils were simulated: sand, loam, sandy loam and clay. In total more than 2.4 million simulations were made with monthly output of carbon content for 30 years. Results demonstrate that crop cover dynamics influence carbon sequestration for a very large percentage. For the same rotations carbon sequestration is highest on clay soils and lowest on sandy soils. Crop residues of grain maize and winter wheat followed by catch crops contribute largely to the total carbon sequestered. This implies that agricultural policies that impact on agricultural land management influence soil carbon sequestration for a large percentage. The framework is therefore suited for further scenario analysis and impact assessment in order to support agri-environmental policy decisions.

Detection of high concentrations of organic acids in fish emulsion and their role in pathogen or disease suppression.

PubMed

Abbasi, Pervaiz A; Lazarovits, George; Jabaji-Hare, Suha

2009-03-01

Fish emulsion (FE) added to a sandy-loam soil at 1 and 2% rates reduced the viability of Verticillium dahliae microsclerotia by 39 and 74% in 1 day, 87 and 98% in 3 days, and 95 and 99% in 6 days, respectively. The immediate kill of microsclerotia indicated that FE contains toxic substances. We found in FE high concentrations (400 mmol/liter) of organic acids, including some known toxicants. Glycolic, acetic, formic, n-butyric, and propionic acids were the major organic acids detected in FE at the proportions of 52.5, 26.9, 7.9, 7.2, and 4.7%, respectively. In solution assays, the viability of V. dahliae microsclerotia treated for 24 h in 1, 2, 5, and 10% FE (pH 3.6 to 3.0) or a mixture of organic acids (pH 4.1 to 3.9) equivalent to the proportions in FE was reduced by 74, 94, 97, and 99% or 81, 91, 98, and 99%, respectively. The viability of microsclerotia was increased when the treatment solutions were buffered to pH 6.0. The organic acids mixtures and formic (0.025%) and acetic (0.1%) acids were toxic to Pythium ultimum. A mixture of organic acids (1, 2, and 4%) provided immediate protection of cucumber seedlings from damping-off in P. ultimum-infested muck and sandy-loam soils but not in peat-based mix. FE (1 and 2%) provided immediate protection of cucumber seedlings from damping-off in an infested muck soil, and disease protection was consistent when planting was delayed for 7, 14, and 28 days after adding FE. FE (1, 2, and 4%) did not provide immediate protection of cucumber seedlings from damping-off in a P. ultimum-infested peat-based mix; however, disease suppression was evident when planting was delayed for 7, 14, and 21 days after adding FE. Real-time polymerase chain reaction analyses of the peat-based mix indicated that the P. ultimum populations in the FE-amended mix declined over time. This study suggests that these organic acids in FE played a major role in pathogen or disease suppression, depending on the soil and substrate.

Estimation of evapotranspiration rate in irrigated lands using stable isotopes

NASA Astrophysics Data System (ADS)

Umirzakov, Gulomjon; Windhorst, David; Forkutsa, Irina; Brauer, Lutz; Frede, Hans-Georg

2013-04-01

Agriculture in the Aral Sea basin is the main consumer of water resources and due to the current agricultural management practices inefficient water usage causes huge losses of freshwater resources. There is huge potential to save water resources in order to reach a more efficient water use in irrigated areas. Therefore, research is required to reveal the mechanisms of hydrological fluxes in irrigated areas. This paper focuses on estimation of evapotranspiration which is one of the crucial components in the water balance of irrigated lands. Our main objective is to estimate the rate of evapotranspiration on irrigated lands and partitioning of evaporation into transpiration using stable isotopes measurements. Experiments has done in 2 different soil types (sandy and sandy loam) irrigated areas in Ferghana Valley (Uzbekistan). Soil samples were collected during the vegetation period. The soil water from these samples was extracted via a cryogenic extraction method and analyzed for the isotopic ratio of the water isotopes (2H and 18O) based on a laser spectroscopy method (DLT 100, Los Gatos USA). Evapotranspiration rates were estimated with Isotope Mass Balance method. The results of evapotranspiration obtained using isotope mass balance method is compared with the results of Catchment Modeling Framework -1D model results which has done in the same area and the same time.

Application of Microtremor Survey Methods to Determine the Shallow Crustal S-wave Velocity Structure beneath the Wudalianchi Weishan Volcano Area

NASA Astrophysics Data System (ADS)

Zhang, B.; LI, Z.; Chu, R.

2015-12-01

Ambient noise has been proven particularly effective in imaging Earth's crust and uppermost mantle on local, regional and global scales, as well as in monitoring temporal variations of the Earth interior and determining earthquake ground truth location. Previous studies also have shown that the Microtremor Survey Method is effective to map the shallow crustal structure. In order to obtain the shallow crustal velocity structure beneath the Wudalianchi Weishan volcano area, an array of 29 new no-cable digital geophones were deployed for three days at the test site (3km×3km) for recording continuously seismic noise. Weishan volcano is located in the far north of Wudalianchi Volcanoes, the volcanic cone is composed of basaltic lava and the volcano area covered by a quaternary sediments layer (gray and black loam, brown and yellow loam, sandy loam). Accurate shallow crustal structure, particularly sedimentary structure model can improve the accuracy of location of volcanic earthquakes and structural imaging. We use ESPAC method, which is one of Microtremor Survey Methods, to calculate surface wave phase velocity dispersion curves between station pairs. A generalized 2-D linear inversion code that is named Surface Wave Tomography (SWT) is adopted to invert phase velocity tomographic maps in 2-5 Hz periods band. On the basis of a series of numerical tests, the study region is parameterized with a grid spacing of 0.1km×0.1km, all damping parameters and regularization are set properly to ensure relatively smooth results and small data misfits as well. We constructed a 3D Shallow Crustal S-wave Velocity model in the area by inverting the phase velocity dispersion curves at each node adopting an iterative linearized least-square inversion scheme of surf96. The tomography model is useful in interpreting volcanic features.

Effect of intermediate soil cover on municipal solid waste decomposition.

PubMed

Márquez-Benavides, L; Watson-Craik, I

2003-01-01

A complex series of chemical and microbiological reactions is initiated with the burial of refuse in a sanitary landfill. At the end of each labour day, the municipal solid wastes (MSW) are covered with native soil (or an alternative material). To investigate interaction between the intermediate cover and the MSW, five sets of columns were set up, one packed with refuse only, and four with a soil-refuse mixture (a clay loam, an organic-rich peaty soil, a well limed sandy soil and a chalky soil). The anaerobic degradation over 6 months was followed in terms of leachate volatile fatty acids, chemical oxygen demand, pH and ammoniacal-N performance. Results suggest that the organic-rich peaty soil may accelerate the end of the acidogenic phase. Clay appeared not to have a significant effect on the anaerobic degradation process.

Effect of Soil Water on Infectivity and Development of Rotylenchulus reniformis on Soybean, Glycine max

PubMed Central

Rebois, R. V.

1973-01-01

The effect of soil water content on Rotylenchulus reniformis infectivity of 'Lee' soybean roots was investigated in an autoclaved sandy clay loam. Nematodes were introduced into soil masses maintained at constant soil water levels ranging from 3.4 to 19% by weight. Seedling growth and the soil water content-water potential relationships of the soil were determined. Nematode infectivity was greatest when the soil water content was maintained just below field capacity in the 7.2 (-1/3 bar) to 13.0% (-1/7 bar) ranges. Nematode invasion of roots was reduced in the wetter 15.5 (-1/10 bar) to 19.0% (-1 /2 0 bar) soil moisture ranges and in the dryer 3.4 (-15 bar) to 5.8% (-3/4 bar) soil moisture ranges. PMID:19319344

Compared Biochar and Compost effects on plant growth and soil factors as reported for three consequent greenhouse trial setups

NASA Astrophysics Data System (ADS)

Schulz, H. S.; Glaser, B. G.

2012-04-01

Since ten years there is a major increase in research concerning biochar applications to soils trying to mimic effects known from Terra Preta do Indio (Glaser 2002). We conducted a preliminary study in which we analyzed the synergistic effects of biochar in combination with conventional and with organic fertilizers, whereas our latter experiments use biochar which was blended with fresh organic material and underwent the whole composting procedure leading to the first known composted biochars. Our first pot experiment (with two consequent growth periods without additional fertilization) helped to distinguish the effects from conventional and organic fertilizers in combination with biochar, where biochar revealed abilities for stabilizing carbon content (Total Organic and Black Carbon) and reducing nitrification. Plant weights were highest with pure compost, but biochar combined with compost (50:50) showed a sustained progression comparing second growth period's results. Those outcomes let us focus on biochar-compost-mixes. Our second greenhouse experiment concentrated on the question of the minimal biochar content to enhance plant growth and soil properties and was performed on a very poor sandy and on a richer loamy soil with rising concentrations between 0% and 1% biochar per compost. We could not find significant differences between the pure compost and the biochar amended pots. For our third experiment we tried to elevate the biochar share as high as possible and tested treatments with up to 200 Mg ha-1(eq.) in steps with up to 50% biochar content, again in poor sandy and richer loamy soil pots. The measured seed weight of applied Avena sativa L. plants showed very different results on sandy soil compared to the loamy soil. Whereas compost on loam showed a seed weight 2 times higher than on pure loam control and seed weights 1.6 times higher compared to compost with highest biochar amounts, on sand the pure compost was even slightly less productive than pure sand control (factor: 0.8) and the highest biochar applications yielded 13.8 times the seed harvest of the sand compost (10.4 times sand control). We will try to present possible explanations for those results based on TOC, TN, pH, NO3, NH4 and electrical conductivity data. - Bridle, T.R., Pritchard, D., 2004. Energy and nutrient recovery from sewage sludge via pyrolysis. Water Science and Technology 50, 169-175. - Glaser, B.; Lehmann, J.; Zech, W. (2002): Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal - a review. Biology and Fertility of Soils, 35, 219-230. - Lehmann, J. and Joseph, S. (eds.) (2010): Biochar for environmental management. Science and technology. Earthscan. London.

Infiltration in layered loessial deposits: Revised numerical simulations and recharge assessment

NASA Astrophysics Data System (ADS)

Dafny, Elad; Šimůnek, Jirka

2016-07-01

The objective of this study is to assess recharge rates and their timing under layered loessial deposits at the edge of arid zones. Particularly, this study is focused on the case of the coastal plain of Israel and Gaza. First, results of a large-scale field infiltration test were used to calibrate the van Genuchten parameters of hydraulic properties of the loessial sediments using HYDRUS (2D/3D). Second, optimized soil hydraulic parameters were used by HYDRUS-1D to simulate the water balance of the sandy-loess sediments during a 25-year period (1990-2015) for three environmental conditions: bare soil, and soil with both sparse and dense natural vegetation. The best inverse parameter optimization run fitted the infiltration test data with the RMSE of 0.27 d (with respect to a moisture front arrival) and R2 of 96%. The calibrated model indicates that hydraulic conductivities of the two soil horizons, namely sandy loam and sandy clay loam, are 81 cm/d and 17.5 cm/d, respectively. These values are significantly lower than those previously reported, based on numerical simulations, for the same site. HYDRUS-1D simulation of natural recharge under bare soil resulted in recharge estimates (to the aquifer) in the range of 21-93 mm/yr, with an average recharge of 63 mm/yr. Annual precipitation in the same period varied between 100 and 300 mm/yr, with an average of 185 mm/yr. For semi-stabilized dunes, with 26% of the soil surface covered by local shrub (Artemisia monosperma), the mean annual recharge was 28 mm. For the stabilized landscape, with as much as 50% vegetation coverage, it was only 2-3 mm/yr. In other words, loessial sediments can either be a source of significant recharge, or of no recharge at all, depending on the degree of vegetative cover. Additionally, the time lag between specific rainy seasons and corresponding recharge events at a depth of 22 m, increased from 2.5 to 5 years, and to about 20 years, respectively, with an increasing vegetative cover. For this reason, and also likely due to a great depth of loessial sediments, no correlation was found between annual recharge and annual precipitations of the same year or subsequent years. Similarly, no differences were found between summer and winter recharge fluxes. Instead, numerical simulations indicated continuous year-round recharge of the aquifer. We conclude that the layered subsurface acts as a short-term (annual) and long-term (multi-annual) buffer to smooth sudden precipitation/infiltration events. Vegetation conditions can help in predicting long-term recharge rates (as percentage of annual precipitation), which in turn need to be considered when assigning recharge characteristics in regional assessments and models.

Carbonate pseudomatrix in siliciclastic-carbonate turbidites from the Oquirrh-Wood River basin, southern Idaho

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

Geslin, J.K.

1994-01-01

Upper Pennsylvanian to Lower Permian mixed siliciclastic-carbonate sandy turbidites from the Oquirrh-Wood River basin in southern Idaho contain 20 to 60 modal percent microspar and pseudospar. Previous interpretations suggested that neomorphism of detrital lime mud produced the observed carbonate textures. The original detrital lime mud produced the observed carbonate textures. The original detrital lime mud content, based on these interpretations, indicates matrix-rich, poorly sorted turbidite deposits. However, observed turbidite hydrodynamics, and grain-size data from experimental and naturally occurring sandy turbidite deposits, indicate that T[sub n]-T[sub c] intervals of sandy turbidites are generally moderately well sorted, with low matrix content. Fluorescencemore » microscopy reveals that the carbonate fraction of these mixed siliciclastic-carbonate turbidites contains micritized skeletal grains and fusulinids, and algal peloids. These micritized grains and peloids were physically compacted and neomorphosed to form a carbonate pseudomatrix. Formation of carbonate pseudomatrix is analogous to formation of pseudomatrix in siliciclastic lithic sands, which includes crushing and recrystallization of lithic grains. Grain-size analysis of siliciclastic and slightly compacted carbonate grains indicates that these are moderately well sorted turbidite deposits with similar grain-size populations in both fractions. Lack of recognition of carbonate pseudomatrix could lead to erroneous interpretations of carbonate petrology. Identification of carbonate pseudomatrix is important to the study of mixed siliciclastic-carbonate gravity-flow deposits. This study demonstrates the value of fluorescence microscopy in the recognition of carbonate pseudomatrix.« less

Mixed-mode isolation of triazine metabolites from soil and aquifer sediments using automated solid-phase extraction

USGS Publications Warehouse

Mills, M.S.; Thurman, E.M.

1992-01-01

Reversed-phase isolation and ion-exchange purification were combined in the automated solid-phase extraction of two polar s-triazine metabolites, 2-amino-4-chloro-6-(isopropylamino)-s-triazine (deethylatrazine) and 2-amino-4-chloro-6-(ethylamino)-s-triazine (deisopropylatrazine) from clay-loam and slit-loam soils and sandy aquifer sediments. First, methanol/ water (4/1, v/v) soil extracts were transferred to an automated workstation following evaporation of the methanol phase for the rapid reversed-phase isolation of the metabolites on an octadecylresin (C18). The retention of the triazine metabolites on C18 decreased substantially when trace methanol concentrations (1%) remained. Furthermore, the retention on C18 increased with decreasing aqueous solubility and increasing alkyl-chain length of the metabolites and parent herbicides, indicating a reversed-phase interaction. The analytes were eluted with ethyl acetate, which left much of the soil organic-matter impurities on the resin. Second, the small-volume organic eluate was purified on an anion-exchange resin (0.5 mL/min) to extract the remaining soil pigments that could foul the ion source of the GC/MS system. Recoveries of the analytes were 75%, using deuterated atrazine as a surrogate, and were comparable to recoveries by soxhlet extraction. The detection limit was 0.1 ??g/kg with a coefficient of variation of 15%. The ease and efficiency of this automated method makes it viable, practical technique for studying triazine metabolites in the environment.

Differences in Soil Moisture Dynamics across Landforms in South Texas Shrublands

NASA Astrophysics Data System (ADS)

Basant, S.; Wilcox, B. P.

2016-12-01

To understand the water budget for a landscape, it is important to understand the hydrologic differences between different landforms constituting the landscape. The Tamaulipas Biotic Province shrublands in South Texas are characterized by primarily three different landforms - the sandy loam uplands, clay loam intermittent drainage woodlands and closed basin depressions situated in intermittent drainage ways, also referred to as `playas'. Texas A&M's La Copita Research Area (LCRA) in South Texas is a similar landscape where previous research has been limited to soil water movement in uplands and localized water accumulation in the playa landforms. The objective of this research is to understand the hydrology of different landforms and integrate them to complete a landscape scale water budget. Deep soil water movement will be measured at LCRA using neutron moisture gauges. Over 50 access tubes distributed around the site will be used to cover the dominant landforms and vegetation classes. Soil moisture will be measured up to a depth of 2m at different times of the year - so as to capture the variability in response to different rain events and also to different seasons. This will be complimented by over 6 years of run off data collected from controlled plots which will provide an estimate on the amount of overland water exchange from uplands to drainage and playas. The depth-wise soil moisture data collected over time will also be used to estimate the variability in plant water uptake rates across different sites.

Wind-driven rain and its implications for natural hazard management

NASA Astrophysics Data System (ADS)

Marzen, Miriam; Iserloh, Thomas; de Lima, João L. M. P.; Fister, Wolfgang; Ries, Johannes B.

2017-04-01

Prediction and risk assessment of hydrological extremes are great challenges. Following climate predictions, frequent and violent rainstorms will become a new hazard to several regions in the medium term. Particularly agricultural soils will be severely threatened due to the combined action of heavy rainfall and accompanying winds on bare soil surfaces. Basing on the general underestimation of the effect of wind on rain erosion, conventional soil erosion measurements and modeling approaches lack related information to adequately calculate its impact. The presented experimental-empirical approach shows the powerful impact of wind on the erosive potential of rain. The tested soils had properties that characterise three different environments 1. Silty loam of semi-arid Mediterranean dryfarming and fallow, 2. clayey loam of humid agricultural sites and 3. cohesionless sandy substrates as found at coasts, dune fields and drift-sand areas. Erosion was found to increase by a factor of 1.3 to 7.1, depending on site characteristics. Complementary tests with a laboratory procedure were used to quantify explicitly the effect of wind on raindrop erosion as well as the influence of substrate, surface structure and slope on particle displacement. These tests confirmed the impact of wind-driven rain on total erosion rates to be of great importance when compared to all other tested factors. To successfully adapt soil erosion models to near-future challenges of climate change induced rain storms, wind-driven rain is supposed to be introduced into the hazard management agenda.

Geomorphology of the Chippewa River delta of Glacial Lake Saginaw, central Lower Michigan, USA

NASA Astrophysics Data System (ADS)

Connallon, Christopher B.; Schaetzl, Randall J.

2017-08-01

We introduce, characterize, and interpret the geomorphic history of a relict, Pleistocene-aged delta of the Chippewa River in central Lower Michigan. The broad, sandy Chippewa delta developed into various stages of Glacial Lake Saginaw, between ca. ≈ 17 and 15 ka·BP (calibrated ages). Although the delta was first identified in 1955 on a statewide glacial geology map, neither its extent nor its Pleistocene history had been previously determined. The delta is typically forested, owing to its wet, sandy soils, which stand out against the agricultural fields of the surrounding, loamy lake plain sediments. The delta heads near the city of Mt Pleasant and extends eastward onto the Saginaw Lowlands, i.e., the plain of Glacial Lake Saginaw. Data from 3285 water well logs, 180 hand augered sites, and 185 points randomly located in a GIS on two-storied (sand over loam) soils were used to determine the extent, textural properties, and thickness of the delta. The delta is ≈ 18 km wide and ≈ 38 km long and is sandy throughout. Deltaic sediments from neighboring rivers that also drained into Glacial Lake Saginaw merge with the lower Chippewa delta, obscuring its boundary there. The delta is thickest near the delta's head and in the center, but thins to 1-2 m or less on its eastern margins. Mean thicknesses are 2.3-2.9 m, suggestive of a thin sediment body, frequently impacted by the waves and fluctuating waters of the lakes. Although beach ridges are only weakly expressed across the delta because of the sandy sediment, the coarsest parts of the delta are generally coincident with some of these inferred former shorezones and have a broad, incised channel that formed while lake levels were low. The thick upper delta generally lies above the relict shorelines of Glacial Lakes Saginaw and Arkona (≈ 17.1 to ≈ 16 ka·BP), whereas most of the thin, distal delta is associated with Glacial Lake Warren (≈ 15 ka·BP). Together, these data suggest that the Chippewa delta formed and prograded as lake levels in the Saginaw Lowlands alternated and episodically fell. The result is a delta that is comparatively thin, expansive, and sandy. In some places, these sands have subsequently been reworked into fields of small parabolic dunes.

The influence of compost addition on the water repellency of brownfield soils

NASA Astrophysics Data System (ADS)

Whelan, Amii; Kechavarzi, Cedric; Sakrabani, Ruben; Coulon, Frederic; Simmons, Robert; Wu, Guozhong

2010-05-01

Compost application to brownfield sites, which can facilitate the stabilisation and remediation of contaminants whilst providing adequate conditions for plant growth, is seen as an opportunity to divert biodegradable wastes from landfill and put degraded land back into productive use. However, although compost application is thought to improve soil hydraulic functioning, there is a lack of information on the impact of large amounts of compost on soil water repellency. Water repellency in soils is attributed to the accumulation of hydrophobic organic compounds released as root exudates, fungal and microbial by-products and decomposition of organic matter. It has also been shown that brownfield soils contaminated with petroleum-derived organic contaminants can exhibit strong water repellency, preventing the rapid infiltration of water and leading potentially to surface run off and erosion of contaminated soil. However, hydrophobic organic contaminants are known to become sequestrated by partitioning into organic matter or diffusing into nano- and micropores, making them less available over time (ageing). The effect of large amounts of organic matter addition through compost application on the water repellency of soils contaminated with petroleum-derived organic contaminants requires further investigation. We characterised the influence of compost addition on water repellency in the laboratory by measuring the Water Drop Penetration Time (WDPT), sorptivity and water repellency index through infiltration experiments on soil samples amended with two composts made with contrasting feedstocks (green waste and predominantly meat waste). The treatments consisted of a sandy loam, a clay loam and a sandy loam contaminated with diesel fuel and aged for 3 years, which were amended with the two composts at a rate equivalent to 750t/ha. In addition core samples collected from a brownfield site, amended with compost at three different rates (250, 500 and 750t/ha) in 2007, were also tested. The results show that the water repellency of air dried samples is significantly higher in samples amended with composts and increases with increasing organic matter content. The WDPT suggests that compost, when dry, is hydrophobic. Diesel contamination leads to a decrease in sorptivity compared to uncontaminated controls and wettability is not re-established following the addition of compost. Finally, the increase in compost volume (i.e. application rate) in the field samples leads to an increase in water repellency. The infiltration tests, carried out using a miniature tension infiltrometer, also illustrate different effects of hydrophobicity on infiltration, with some samples demonstrating reduced infiltration and low sorptivity but others showing no infiltration at all until the breakdown of repellency at later times. This investigation is currently being complemented by a study of the influence of hydrophobic organic contaminant sequestration with time (i.e. ageing), estimated by measuring the changes in the available fraction of polycyclic aromatic hydrocarbons (PAHs), on the water repellency of compost amended brownfield soils.

Evapotranspiration and crop coefficient of oil palm (Elaeis guineensis Jacq.) on the main nursery in a greenhouse

NASA Astrophysics Data System (ADS)

Sigalingging, R.; Sumono; Rahmansyah, N.

2018-02-01

The estimation of crop water requirement is an important part of oil palm plantation because fruit yield of oil palm can be affected by water stress. Evapotranspiration and crop coefficient of oil palm using Tenera variety at 7-12 months old was determined. Soil texture was sandy loam with 73.8 % sand, 10.8 % silt, 15.77 % clay and 1.41 % organic matter. The results showed that the oil palm getting older decreased significantly in bulk density, particle density and porosity of soil caused the root of oil palm enlarged (19.42 g to 53.37 g). This was indicated by increased the dry root weight. On the other hand, the value of evapotranspiration and crop coefficient increased significantly, that was 1.85 to 2.00 mm/day and 0.8 to 0.87 respectively.

Assessment of the physicochemical and microbiological status of western Niger Delta soil for crude oil pollution bioremediation potential.

PubMed

Ejechi, Bernard O; Ozochi, Chizoba A

2015-06-01

The physical, chemical and microbiological characteristics of the soil across the western Niger Delta area of Nigeria were determined to assess its potential for natural remediation of crude oil pollution. The pH (oil-producing area, 6.1 ± 1.1; non-oil producing, 5.9 ± 0.9) and temperature (28-35 °C in both areas) were favourable to natural remediation, while the fluctuating moisture (7.7-45.6 %) and the dominant sandy soil textural classes (70 %) were limitations. The carbon nitrogen phosphorus (CNP) ratio markedly exceeded recommended 100:10:1, while the cation exchange capacity was below acceptable range. Counts of heterotrophic bacteria, fungi and hydrocarbon-utilising and nitrogen-fixing bacteria (mean range log10 3.8 ± 1.5-6.52 ± 0.9 cfu/g) were favourable having markedly exceeded the minimum counts required. Crude oil loss was highest in loam soil, but significantly (P = 0.00) increased in all soil textural classes including sandy soils after amendment with cow dung/poultry dropping and manual aeration in laboratory and 8-month field tests as indicated by two-way ANOVA. Thus, the overall assessment is that while CNP can be viewed as the major limiting factor to natural oil pollution remediation in the western Niger Delta soil, its influence can be minimised by the amendment indicated in the study.

Pupal development of Ceratitis capitata (Diptera: Tephritidae) and Diachasmimorpha longicaudata (Hymenoptera: Braconidae) at different moisture values in four soil types.

PubMed

Bento, F de M M; Marques, R N; Costa, M L Z; Walder, J M M; Silva, A P; Parra, J R P

2010-08-01

This study aimed to evaluate adult emergence and duration of the pupal stage of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), and emergence of the fruit fly parasitoid, Diachasmimorpha longicaudata (Ashmead), under different moisture conditions in four soil types, using soil water matric potential. Pupal stage duration in C. capitata was influenced differently for males and females. In females, only soil type affected pupal stage duration, which was longer in a clay soil. In males, pupal stage duration was individually influenced by moisture and soil type, with a reduction in pupal stage duration in a heavy clay soil and in a sandy clay, with longer duration in the clay soil. As matric potential decreased, duration of the pupal stage of C. capitata males increased, regardless of soil type. C. capitata emergence was affected by moisture, regardless of soil type, and was higher in drier soils. The emergence of D. longicaudata adults was individually influenced by soil type and moisture factors, and the number of emerged D. longicaudata adults was three times higher in sandy loam and lower in a heavy clay soil. Always, the number of emerged adults was higher at higher moisture conditions. C. capitata and D. longicaudata pupal development was affected by moisture and soil type, which may facilitate pest sampling and allow release areas for the parasitoid to be defined under field conditions.

Response of Soil Bulk Density and Mineral Nitrogen to Harvesting and Cultural Treatments

Treesearch

Minyi Zhou; Mason C. Carter; Thomas J. Dean

1998-01-01

The interactive effects of harvest intensity, site preparation, and fertilization on soil compaction and nitrogen mineralization were examined in a loblolly pine (Pinus taeda L.) stand growing on a sandy, well-drained soil in eastern Texas. The experimental design was 2 by 2 by 2 factorial, consisting of two harvesting treatments (mechanical whole-...

Soils of the Eastern mountainsides of the southern Sikhote-Alin (on the example of Lazovsky nature reserve, Russia)

NASA Astrophysics Data System (ADS)

Tregubova, Valentina; Semal, Victoria; Nesterova, Olga; Yaroslavtsev, Alexis

2017-04-01

The most common soils of the southern Far East are Brownzems under Russian classification (Cambisols), which are the zonal ones, emerging on the steep slopes and tops of hills, on high river terraces under broad-leaved and cedar-broad-leaved forests. Those soils formed due to two processes: organic matter metamorphism and clayization by siallite, leading to the formation of clay-metamorphic horizon Bw. The main morphological features of Cambisols are not deep soil profile (50 - 70 cm), weak horizons differentiation, with lots of cobble. Chemically those soils are low saturated, even in the humus horizon. Distribution of total absorbed bases is mostly accumulative, which is related to the distribution of humus in these soils, and the predominant type of clay fraction distribution of. The only exception are Humic Cambisols and Humic Cambisols Calcic which were formed on redeposited products of limestone rock weathering. Fine-grained deposits are mainly loams with a low content of silt. Silt distribution has an accumulative character with a gradual decrease in the content of silt down from the top of the profile. Layer of fresh leaf fall is very common for the Humic Cambisols surfaces, and under it there is the litter of plant residues with different degrees of decomposition. Accumulative humus horizon is dark gray with brownish tint, thin, from 10 to 15 cm in depth, loose, crumbly, highly penetrated by roots, with a strong granular structure, with aggregates tightly attached to the root hairs, sandy loam or sandy clay loam. The middle horizon is brown, yellowish-brown, divided into sub-horizons, with different color intensity, density, soil texture and amount of cobble. Dystric Cambisols are acidic or strongly acidic with low saturation of soil absorbing complex. Due to amount and distribution of organic matter these soils can be divided into two groups. The first group is soils with accumulative humus distribution: with a low depth humus-accumulative horizon (11 - 12 cm) and high content of organic matter (23 - 26 %); humus in the upper horizons mainly consists of humic acids, while in lower horizons it is with higher ratio of fulvic acids. The second group is soils with a gradual humus distribution along the profile and with a smaller amount of organic matter in the upper horizon (9 - 13 %) and with no differentiation in humus composition. Folic Cambisols are formed on the watershed surfaces, on the steep slopes under pine and oak trees. Under thin litter horizon these soils have organic-accumulative horizon of well decomposed organic matter, but in contrast with Dystric Cambisols it doesn't have strong granular structure. At the bottom the organic horizon is humic-impregnated or has clear streaks of humus. Humic Cambisols are formed in the lower parts of slopes, on steep slopes and high river terraces under pine and deciduous forests. All this soils have humified litter horizon, which is up to 7 cm in depth, weak differentiation of the soil profile, deep humus-accumulative horizon (18 - 31 cm) with dark gray, almost black color, with strong granular structure and loam or clay loam texture. Soil acidity is determined by the lithogenic basis. Base saturation is quite high (77 - 90%) in mineral horizons and is up to 70 % in organic and accumulative ones. There is a high amount of humus on the entire profile (5 - 16 %), which consists of humic acids in the upper half of the profile and of fulvates at the bottom. Humic Cambisols Gleyic are located in the lower parts of gentle slopes under mixed forest. Due to higher moisture at the lower parts of slopes this soils have signs of weak gley process in dense subsoil horizons in the form of small light grey spots. Humic Leptosols are weakly developed soils formed on rocky hills, boulders, rocky outcrops, under thick moss layer, under which is a layer of weathered gravel rock. Humic Cambisols (Calcic) are formed on the surface sediments of limestone. They have a deep soil profile, up to 40 cm and it's humus-accumulative horizon is dark gray or black, gradually passing into soil-forming rock. Bw horizon, typical for Cambisols, is weak.

Biochar effect on maize yield and soil characteristics in five conservation farming sites in Zambia

USGS Publications Warehouse

Cornelissen, Gerard; Martinsen, Vegard; Shitumbanuma, Victor; Alling, Vanja; Breedveld, Gijs D.; Rutherford, David W.; Sparrevik, Magnus; Hale, Sarah E.; Obia, Alfred; Mulder, Jan

2013-01-01

Biochar addition to agricultural soils can improve soil fertility, with the added bonus of climate change mitigation through carbon sequestration. Conservation farming (CF) is precision farming, often combining minimum tillage, crop rotation and residue retention. In the present farmer-led field trials carried out in Zambia, the use of a low dosage biochar combined with CF minimum tillage was tested as a way to increase crop yields. Using CF minimum tillage allows the biochar to be applied to the area where most of the plant roots are present and mirrors the fertilizer application in CF practices. The CF practice used comprised manually hoe-dug planting 10-L sized basins, where 10%–12% of the land was tilled. Pilot trials were performed with maize cob biochar and wood biochar on five soils with variable physical/chemical characteristics. At a dosage as low as 4 tons/ha, both biochars had a strong positive effect on maize yields in the coarse white aeolian sand of Kaoma, West-Zambia, with yields of 444% ± 114% (p = 0.06) and 352% ± 139% (p = 0.1) of the fertilized reference plots for maize and wood biochar, respectively. Thus for sandy acidic soils, CF and biochar amendment can be a promising combination for increasing harvest yield. Moderate but non-significant effects on yields were observed for maize and wood biochar in a red sandy clay loam ultisol east of Lusaka, central Zambia (University of Zambia, UNZA, site) with growth of 142% ± 42% (p > 0.2) and 131% ± 62% (p > 0.2) of fertilized reference plots, respectively. For three other soils (acidic and neutral clay loams and silty clay with variable cation exchange capacity, CEC), no significant effects on maize yields were observed (p > 0.2). In laboratory trials, 5% of the two biochars were added to the soil samples in order to study the effect of the biochar on physical and chemical soil characteristics. The large increase in crop yield in Kaoma soil was tentatively explained by a combination of an increased base saturation (from <50% to 60%–100%) and cation exchange capacity (CEC; from 2–3 to 5–9 cmol/kg) and increased plant-available water (from 17% to 21%) as well as water vapor uptake (70 mg/g on maize cob biochar at 50% relative humidity).

Mechanical impedance of soil crusts and water content in loamy soils

NASA Astrophysics Data System (ADS)

Josa March, Ramon; Verdú, Antoni M. C.; Mas, Maria Teresa

2013-04-01

Soil crust development affects soil water dynamics and soil aeration. Soil crusts act as mechanical barriers to fluid flow and, as their mechanical impedance increases with drying, they also become obstacles to seedling emergence. As a consequence, the emergence of seedling cohorts (sensitive seeds) might be reduced. However, this may be of interest to be used as an effective system of weed control. Soil crusting is determined by several factors: soil texture, rain intensity, sedimentation processes, etc. There are different ways to characterize the crusts. One of them is to measure their mechanical impedance (MI), which is linked to their moisture level. In this study, we measured the evolution of the mechanical impedance of crusts formed by three loamy soil types (clay loam, loam and sandy clay loam, USDA) with different soil water contents. The aim of this communication was to establish a mathematical relationship between the crust water content and its MI. A saturated soil paste was prepared and placed in PVC cylinders (50 mm diameter and 10 mm height) arranged on a plastic tray. Previously the plastic tray was sprayed with a hydrophobic liquid to prevent the adherence of samples. The samples on the plastic tray were left to air-dry under laboratory conditions until their IM was measured. To measure IM, a food texture analyzer was used. The equipment incorporates a mobile arm, a load cell to apply force and a probe. The arm moves down vertically at a constant rate and the cylindrical steel probe (4 mm diameter) penetrates the soil sample vertically at a constant rate. The equipment is provided with software to store data (time, vertical distance and force values) at a rate of up to 500 points per second. Water content in crust soil samples was determined as the loss of weight after oven-drying (105°C). From the results, an exponential regression between MI and the water content was obtained (determination coefficient very close to 1). This methodology allows the prediction of the potential mechanical behaviour of soil crusts generated during soil drying, from initial saturated soil conditions (e.g. waterlogging conditions).

Combined effects of short-term rainfall patterns and soil texture on nitrogen cycling -- A Modeling Analysis

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

Gu, C.; Riley, W.J.

2009-11-01

Precipitation variability and magnitude are expected to change in many parts of the world over the 21st century. We examined the potential effects of intra-annual rainfall patterns on soil nitrogen (N) transport and transformation in the unsaturated soil zone using a deterministic dynamic modeling approach. The model (TOUGHREACT-N), which has been tested and applied in several experimental and observational systems, mechanistically accounts for microbial activity, soil-moisture dynamics that respond to precipitation variability, and gaseous and aqueous tracer transport in the soil. Here, we further tested and calibrated the model against data from a precipitation variability experiment in a tropical systemmore » in Costa Rica. The model was then used to simulate responses of soil moisture, microbial dynamics, nitrogen (N) aqueous and gaseous species, N leaching, and N trace-gas emissions to changes in rainfall patterns; the effect of soil texture was also examined. The temporal variability of nitrate leaching and NO, N{sub 2}, and N{sub 2}O effluxes were significantly influenced by rainfall dynamics. Soil texture combined with rainfall dynamics altered soil moisture dynamics, and consequently regulated soil N responses to precipitation changes. The clay loam soil more effectively buffered water stress during relatively long intervals between precipitation events, particularly after a large rainfall event. Subsequent soil N aqueous and gaseous losses showed either increases or decreases in response to increasing precipitation variability due to complex soil moisture dynamics. For a high rainfall scenario, high precipitation variability resulted in as high as 2.4-, 2.4-, 1.2-, and 13-fold increases in NH{sub 3}, NO, N{sub 2}O and NO{sub 3}{sup -} fluxes, respectively, in clay loam soil. In sandy loam soil, however, NO and N{sub 2}O fluxes decreased by 15% and 28%, respectively, in response to high precipitation variability. Our results demonstrate that soil N cycling responses to increasing precipitation variability depends on precipitation amount and soil texture, and that accurate prediction of future N cycling and gas effluxes requires models with relatively sophisticated representation of the relevant processes.« less

Development and validation of a quick, easy, cheap, effective, rugged and safe method for the determination of imidacloprid and its metabolites in soil.

PubMed

Akoijam, Romila; Singh, Balwinder; Mandal, Kousik

2015-04-01

A simplified quick, easy, cheap, effective, rugged and safe method was standardized and validated for the estimation of residues of imidacloprid and its metabolites from different types of soil comprising sandy loam, loamy sand and clay loam soil. The samples were extracted with acetonitrile, clean up by treatment with primary secondary amine sorbent and graphitized carbon. High-performance liquid chromatography (HPLC) is a technique to separate and quantitate residues of polar, nonvolatile and thermolabile chemical compounds, using high-pressure pumps, short and narrow columns packed with microparticulate phases and a detector. The residues were estimated using HPLC equipped with a photodiode array detector system, C18 column. Acetonitrile and water (30 : 70) were used as an isocratic mobile phase at 0.3 mL/min. Imidacloprid and its metabolites presented distinct peaks at retention factors of 4.93 min (6-chloronicotinic acid), 7.91 min (nitroguanidine), 9.12 min (olefin), 11.32 min (nitrosimine), 13.82 min (urea), 15.45 min (5-hydroxy) and 22.47 min (imidacloprid). Consistent recoveries above 80% for imidacloprid and its metabolites were observed when samples were spiked at 0.01, 0.05 and 0.10 mg/kg levels. The limit of quantification of the method was 0.01 mg/kg. The analytical method was validated in terms of parameters including selectivity, linearity, precision and accuracy of the detection system. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Temperature effect on the transport of bromide and E. coli NAR in saturated soils

NASA Astrophysics Data System (ADS)

Gharabaghi, B.; Safadoust, A.; Mahboubi, A. A.; Mosaddeghi, M. R.; Unc, A.; Ahrens, B.; Sayyad, Gh.

2015-03-01

In this study we investigated the transport of nalidixic acid-resistant Escherichia coli (E. coli NAR) and bromide (Br-) through two soils, a sandy loam (SL) and clay loam (CL). Soils were repacked in columns (45 cm length × 22 cm diameter) and subjected to physical (freeze/thaw, and wet/dry cycles) and biological (by earthworms, Eisenia fetida) weathering for 12 months. Saturated flow conditions were maintained using a tension infiltrometer. Tests were carried out at either 5 or 20 °C. After steady-state flow conditions were established, a suspension containing E. coli NAR and Br- was sprayed onto the surface of soil columns. Leachate was sampled at three depths, 15, 30 and 45 cm. Time to maximum concentration (Cmax) of E. coli NAR was greater for SL at all depths. Both tracers had rapid breakthrough curves (BTCs) shortly after the suspension injection followed by prolonged tailing indicating the presence of preferential pathways and thus soil heterogeneity regenerated after the induced physical and biological weathering. About 40% of the E. coli NAR and 79% of the Br- leached through the entire 45 cm soil columns during the experiments. Leaching with cold water (5 °C) led to lower hydraulic conductivity and flow rate and consequently enhanced bacterial filtration for both soils. Very low values for the detachment coefficient for E. coli NAR at 5 °C suggest an irreversible process of bacterial attachment in heterogeneous soils. BTCs were well described by the mobile-immobile model (MIM) in HYDRUS-1D. Soil texture/structure and temperature had a significant effect on the model's fitted parameters.

Phytotoxic effects of Cu and Zn on soybeans grown in field-aged soils: their additive and interactive actions.

PubMed

Kim, Bojeong; McBride, Murray B

2009-01-01

A field pot experiment was conducted to investigate the interactive phytotoxicity of soil Cu and Zn on soybean plants [Glycine max (L.) Merr.]. Two soils (Arkport sandy loam [coarse-loamy, mixed, active, mesic Lamellic Hapludalf] and Hudson silty clay loam [fine, illitic, mesic Glossaquic Hapludalf]) spiked with Cu, Zn, and combinations of both to reach the final soil metal range of 0 to 400 mg kg(-1) were tested in a 2-yr bioassay after 1 yr of soil-metal equilibration in the field. The soluble and easily-extractable fraction of soil Zn (or Cu), estimated by dilute CaCl2, increased linearly in response to the total Zn (or Cu) added. This linearity was, however, strongly affected where soils were treated with both metals in combination, most notably for Zn, as approximately 50% more of soil Zn was extracted into solution when the Cu level was high. Consequently, added Zn is less likely to be stabilized by aging than added Cu when both metals are present in field soils. The predictive model relating soil metal extractability to plant Zn concentration also revealed a significant Cu-Zn interaction. By contrast, the interaction between the two metals contributed little to explain plant Cu uptake. The additive action of soil Cu and Zn was of considerable importance in explaining plant biomass reduction. This work clearly demonstrates the critical roles of the properties of the soil, the nature of the metal, and the level of other toxic metals present on the development of differential phytotoxicity due to soil Cu and Zn.

Slopewash, surface runoff and fine-litter transport in forest and landslide scars in humid-tropical steeplands, Luquillo Experimental Forest, Puerto Rico

USGS Publications Warehouse

Larsen, M.C.; Torres-Sanchez, A. J.; Concepcion, I.M.

1999-01-01

Rainfall, slopewash (the erosion of soil particles), surface runoff and fine-litter transport at humid-tropical steepland sites in the Luquillo Experimental Forest, Puerto Rico (18??20' N, 65??45' W) were measured from 1991 to 1995. Hillslopes underlain by (1) Cretaceous tuffaceous sandstone and siltstone in subtropical rain (tabonuco) forest with vegetation recovering from Hurricane Hugo (1989), and (2) Tertiary quartz diorite in subtropical lower montane wet (colorado and dwarf) forest with undisturbed forest canopy were compared to recent landslide scars. Monthly surface runoff on these very steep hillslopes (24??to 43??) was only 0.2 to 0.5 per cent of monthly rainfall. Slopewash was higher in sandy loam soils whose parent material is quartz diorite (averaging 46 g m-2 a-1) than in silty clay loam soils derived from tuffaceous sandstone and siltstone where the average was 9 g m-2 a-1. Annual slopewash of 100 to 349 g m-2 on the surfaces of two recent, small landslide scars was measured initially but slopewash decreased to only 3 to 4 g m-2 a-1 by the end of the study. The mean annual mass of fine litter (mainly leaves and twigs) transported downslope at the forested sites ranged from 5 to 8 g m-2 and was lower at the tabonuco forest site, where post-Hurricane Hugo recovery is still in progress. Mean annual fine-litter transport was 2.5 g m-2 on the two landslide scars.

A model to predict the effects of soil structure on denitrification and N 2O emission

NASA Astrophysics Data System (ADS)

Laudone, G. M.; Matthews, G. P.; Bird, N. R. A.; Whalley, W. R.; Cardenas, L. M.; Gregory, A. S.

2011-10-01

SummaryA model of the void space of soil is presented, and used for the a priori biophysical simulation of denitrification. The model comprises a single critical percolation channel through a 5 cm stack of four unit cells of a dual-porous void structure. Together, the micro- and macro-porous structures closely replicate the full water retention characteristic of a sandy clay loam soil from the Woburn Experimental Farm operated by Rothamsted Research, UK. Between 1 and 10 micro-porous hot-spot zones of biological activity were positioned at equally spaced distances within 5 cm from the surface, and at either 10 μm or 100 μm from the critical percolation channel. Nitrification and denitrification reactions within the hotspots were assumed to follow Michaelis-Menten kinetics, with estimated values of rate coefficients. Estimates were also made of the threshold values of oxygen concentration below which the anaerobic processes would commence. The pore network was fully saturated following addition of an aqueous 'amendment' of nitrate and glucose which started the reactions, and which mirrored an established laboratory protocol. Diffusion coefficients for Fickian and Crank-Nicolson calculations were taken from the literature, and were corrected for the tortuosity of the micro-porosity. The model was used to show the amount of carbon dioxide, nitrous oxide and molecular nitrogen emerging from the simulated soil with time. Adjustment of the rate coefficient and oxygen threshold concentrations, within the context of a sensitivity analysis, gave emission curves in good agreement with previous experimental measurements. Positioning of the hot-spot zones away from the critical percolation path slowed the increase and decline in emission of the gases. The model and its parameters can now be used for modelling the effect of soil compaction and saturation on the emission of nitrous oxide.

Principles of control automation of soil compacting machine operating mechanism

NASA Astrophysics Data System (ADS)

Anatoly Fedorovich, Tikhonov; Drozdov, Anatoly

2018-03-01

The relevance of the qualitative compaction of soil bases in the erection of embankment and foundations in building and structure construction is given.The quality of the compactible gravel and sandy soils provides the bearing capability and, accordingly, the strength and durability of constructed buildings.It has been established that the compaction quality depends on many external actions, such as surface roughness and soil moisture; granulometry, chemical composition and degree of elasticity of originalfilled soil for compaction.The analysis of technological processes of soil bases compaction of foreign and domestic information sources showed that the solution of such important problem as a continuous monitoring of soil compaction actual degree in the process of machine operation carry out only with the use of modern means of automation. An effective vibrodynamic method of gravel and sand material sealing for the building structure foundations for various applications was justified and suggested.The method of continuous monitoring the soil compaction by measurement of the amplitudes and frequencies of harmonic oscillations on the compactible surface was determined, which allowed to determine the basic elements of facilities of soil compacting machine monitoring system of operating, etc. mechanisms: an accelerometer, a bandpass filter, a vibro-harmonics, an on-board microcontroller. Adjustable parameters have been established to improve the soil compaction degree and the soil compacting machine performance, and the adjustable parameter dependences on the overall indexhave been experimentally determined, which is the soil compaction degree.A structural scheme of automatic control of the soil compacting machine control mechanism and theoperation algorithm has been developed.

Composition, structure and properties of sediment thermal springs of Kamchatka

NASA Astrophysics Data System (ADS)

Shanina, Violetta; Smolyakov, Pavel; Parfenov, Oleg

2016-04-01

The paper deals with the physical and mechanical properties sediment thermal fields Mutnovsky, Lower Koshelevo and Bannyh (Kamchatka). This multi-component soils, mineral and chemical composition of which depends on the formation factors (pH, temperature, salinity of water, composition and structure of the host volcanic rocks). Samples Lower Koshelevo sediment thermal sources differ in the following composition: smectite, kaolinite, kaolinite-smectite mixed-mineral. Samples of sediment thermal springs Mutnovsky volcano in accordance with the X-ray analysis has the following composition: volcanic glass, crystalline sulfur, plagioclase, smectite, illite-smectite mixed, illite, chlorite, quartz, cristobalite, pyrite, melanterite, kaolinite. Natural moisture content samples of sediment thermal springs from 45 to 121%, hygroscopic moisture content of 1.3 to 3.7%. A large amount of native sulfur (up to 92%) and the presence of amorphous material gives low values of density of solid particles (up to 2.1 g/cm3) samples Mutnovskii thermal field. The values of the density of solids sediment Koshelevo and Bannyh hot springs close to those of the main components of mineral densities (up to 2.6-3.0 g/cm3). The results of the particle size distribution and microaggregate analysis of sediment thermal springs Lower Koshelevo field shows that the predominance observed of particles with a diameter from 0.05 mm to 0.25 mm, the coefficient of soil heterogeneity heterogeneous. In the bottom sediments of the thermal springs of the volcano Mutnovsky poorly traced predominance of one faction. Most prevalent fraction with particle size 0.01 - 0.05 mm. When analyzing the content in the soil microaggregates their content is shifted towards particles with a diameter of 0.25 mm. The contents of a large number of large (1-10 mm), porous rock fragments, due to the deposition of pyroclastic material from the eruptions of the last century. Present in large amounts rounded crystals of native sulfur associated with the rise of mixed solutions, formed at the boundary of secondary boil through faults to the surface thermal boiler (Bortnikova et al., 2009). Calculated flow index and plasticity, shows the classification in accordance with GOST 25100-2011. From these figures it is clear that all the sediments are sandy loam and are in a fluid state. A clear relationship between temperature, pH and particle size distribution of sediment thermal springs can not be traced, great importance is the geological evolution of the volcanic activity, hydrogeological conditions and the time factor. Therefore, samples with a currently active Mutnovsky volcano - sandy loam, sediments of the thermal springs Koshelevo fields are often to loams. The bottom sediments of thermal springs from the territory of the Lower Koshelevo thermal field in a natural occurrence in a state of higher yield strength, so they are an unstable surface, which may cause landslides. The bottom sediments of thermal springs are low explored subject of engineering geology, it is important to examine their properties to simulate the conditions of formation and the development of dangerous processes.

Partitions for high-rise construction using phosphogypsum

NASA Astrophysics Data System (ADS)

Zolotukhin, Sergey; Kukina, Olga; Abramenko, Anatoly

2018-03-01

Gypsum blocks are usually used to make partitions in highrise construction. Reducing the cost of materials used in high-rise construction is an urgent task of modern material science. Phosphogypsum dihydrate, which has binding properties, is one of the large-tonnage waste. The authors have proved that, after years of storage in heaps, water-soluble phosphates, fluorides and other additives included in the structure of fresh phosphogypsum dissolved in water due to weathering (humidification-drying, freezing-thawing in a water-saturated state), and the calcium hydro-and dihydrogen phosphates ingressed in the lattice underwent complete hydrolysis and disintegration, thereby changing the physicochemical properties of phosphogypsum. The data obtained by the authors on the absence of water-soluble compounds of phosphorus, fluorine in stale phosphogypsum indicate its ecological purity and the possibility of application in housing construction. Having analyzed the data of modern methods of differential scanning calorimetry and scanning electron microscopy, the authors predicted and proved by the energy of dehydration of phosphogypsum dihydrate, lime, sandy loam, the possibility of obtaining non-flammable materials with sufficient strength for wall materials. Understanding the processes occurring in water films (the thickness of the water film, the pressure, the temperature and the pH of the aqueous extract of the mixture, the drying of the materials produced), made it possible to develop a technology for obtaining wall products from lime-sandy phosphogypsum material using typical silicate brick production equipment and vibropresses for key-cog blocks production.

Evaluation of distribution and manganese availability in soils under soybean cultivation

NASA Astrophysics Data System (ADS)

Mendes Coutinho, Edson Luiz; de Cássia Gomes São João, Andréia; Mendes Coutinho Neto, André; Corá, José Eduardo; Fernandes, Carolina

2013-04-01

Manganese (Mn) deficiency in soybean became a problem in Brazil, mainly, due to soil low fertility use or soil high pH due to incorrect lime use. However, the manganese deficiency have not been thoroughly investigated. The effect of Mn soil application on Mn distribution among exchangeable, organic matter, amorphous Fe and Al oxides, crystalline Fe and Al oxides, and residual fractions were studied on a Typic Quartzipsament (RQ), a clayey Typic Haplustox (LVA) and a sandy clay loam Typic Haplustox (LV), in a greenhouse experiment carried out in Jaboticabal (SP) - Brazil (21°14'05'' S and 48°17'09'' W). A complete randomized design with three replications of treatments in a 3 x 6 factorial arrangement (three soils and six manganese rates) was used. Five soybean plants were grown during 34 days in pots with 2.5 kg of soil. The Mn contents in these fractions were correlated with those extracted by DTPA and by Mehlich-1 extractants and with soybean shoot Mn contents. Mn rates (0, 5, 10, 20, 40 and 60 mg kg-1) were applied using manganese sulphate (MnSO4). In the Oxisols, most of the Mn was associated with the Fe and Al oxides (amorphous and crystalline) and residual fractions. In the sandy soil (RQ), higher contents were found in exchangeable and residual fractions. Exchangeable fraction was the most important Mn supplier to soybean plants. Multiple regression analysis showed that Mn extracted by DTPA and Mehlich-1 were associated with soil exchangeable fraction.

Variations in water balance and recharge potential at three western desert sites

USGS Publications Warehouse

Gee, G.W.; Wierenga, P.J.; Andraski, Brian J.; Young, M.H.; Fayer, M.J.; Rockhold, M.L.

1994-01-01

Radioactive and hazardous waste landfills exist at numerous desert locations in the USA. At these locations, annual precipitation is low and soils are generally dry, yet little is known about recharge of water and transport of contaminants to the water table. Recent water balance measurements made at three desert locations, Las Cruces, NM, Beatty, NV, and the U.S. Department of Energy's Hanford Site in the state of Washington, provide information on recharge potential under three distinctly different climate and soil conditions. All three sites show water storage increases with time when soils are coarse textured and plants are removed from the surface, the rate of increase being influenced by climatic variables such as precipitation, radiation, temperature, and wind. Lysimeter data from Hanford and Las Cruces indicate that deep drainage (recharge) from bare, sandy soils can range from 10 to >50% of the annual precipitation. At Hanford, when desert plants are present on sandy or gravelly surface soils, deep drainage is reduced but not eliminated. When surface soils are silt loams, deep drainage is eliminated whether plants are present or not. At Las Cruces and Beatty, the presence of plants eliminated deep drainage at the measurement sites. Differences in water balance between sites are attributed to precipitation quantity and distribution and to soil and vegetation types. The implication for waste management at desert locations is that surface soil properties and plant characteristics must be considered in waste site design in order to minimize recharge potential.

Optimization of the Use of His₆-OPH-Based Enzymatic Biocatalysts for the Destruction of Chlorpyrifos in Soil.

PubMed

Senko, Olga; Maslova, Olga; Efremenko, Elena

2017-11-23

Applying enzymatic biocatalysts based on hexahistidine-containing organophosphorus hydrolase (His₆-OPH) is suggested for the decomposition of chlorpyrifos, which is actively used in agriculture in many countries. The application conditions were optimized and the following techniques was suggested to ensure the highest efficiency of the enzyme: first, the soil is alkalinized with hydrated calcitic lime Ca(OH)₂, then the enzyme is introduced into the soil at a concentration of 1000 U/kg soil. Non-equilibrium low temperature plasma (NELTP)-modified zeolite is used for immobilization of the relatively inexpensive polyelectrolyte complexes containing the enzyme His₆-OPH and a polyanionic polymer: poly-l-glutamic acid (PLE 50 ) or poly-l-aspartic acid (PLD 50 ). The soil's humidity is then increased up to 60-80%, the top layer (10-30 cm) of soil is thoroughly stirred, and then exposed for 48-72 h. The suggested approach ensures 100% destruction of the pesticide within 72 h in soils containing as much as 100 mg/kg of chlorpyrifos. It was concluded that using this type of His₆-OPH-based enzyme chemical can be the best approach for soils with relatively low humus concentrations, such as sandy and loam-sandy chestnut soils, as well as types of soil with increased alkalinity (pH 8.0-8.4). Such soils are often encountered in desert, desert-steppe, foothills, and subtropical regions where chlorpyrifos is actively used.

Optimization of the Use of His6-OPH-Based Enzymatic Biocatalysts for the Destruction of Chlorpyrifos in Soil

PubMed Central

Senko, Olga; Efremenko, Elena

2017-01-01

Applying enzymatic biocatalysts based on hexahistidine-containing organophosphorus hydrolase (His6-OPH) is suggested for the decomposition of chlorpyrifos, which is actively used in agriculture in many countries. The application conditions were optimized and the following techniques was suggested to ensure the highest efficiency of the enzyme: first, the soil is alkalinized with hydrated calcitic lime Ca(OH)2, then the enzyme is introduced into the soil at a concentration of 1000 U/kg soil. Non-equilibrium low temperature plasma (NELTP)-modified zeolite is used for immobilization of the relatively inexpensive polyelectrolyte complexes containing the enzyme His6-OPH and a polyanionic polymer: poly-l-glutamic acid (PLE50) or poly-l-aspartic acid (PLD50). The soil’s humidity is then increased up to 60–80%, the top layer (10–30 cm) of soil is thoroughly stirred, and then exposed for 48–72 h. The suggested approach ensures 100% destruction of the pesticide within 72 h in soils containing as much as 100 mg/kg of chlorpyrifos. It was concluded that using this type of His6-OPH-based enzyme chemical can be the best approach for soils with relatively low humus concentrations, such as sandy and loam-sandy chestnut soils, as well as types of soil with increased alkalinity (pH 8.0–8.4). Such soils are often encountered in desert, desert-steppe, foothills, and subtropical regions where chlorpyrifos is actively used. PMID:29168784

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 relatively high C/N ratio and consequently a relatively low rate of nutrient release.

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.

Large herbivores promote habitat specialization and beta diversity of African savanna trees.

PubMed

Pringle, Robert M; Prior, Kirsten M; Palmer, Todd M; Young, Truman P; Goheen, Jacob R

2016-10-01

Edaphic variation in plant community composition is widespread, yet its underlying mechanisms are rarely understood and often assumed to be physiological. In East African savannas, Acacia tree species segregate sharply across soils of differing parent material: the ant-defended whistling thorn, A. drepanolobium (ACDR), is monodominant on cracking clay vertisols that are nutrient rich but physically stressful, whereas poorly defended species such as A. brevispica (ACBR) dominate on nutrient-poor but otherwise less-stressful sandy loams. Using a series of field experiments, we show that large-mammal herbivory interacts with soil properties to maintain this pattern. In the absence of large herbivores, transplanted saplings of both species established on both soil types. Browsers strongly suppressed survival and growth of ACDR saplings on sandy soil, where resource limitation constrained defensive investment. On clay soil, ACBR saplings established regardless of herbivory regime, but elephants prevented recruitment to maturity, apparently because trees could not tolerate the combination of biotic and abiotic stressors. Hence, each tree species was filtered out of one habitat by browsing in conjunction with different edaphic factors and at different ontogenetic stages. Browser abundance was greater on sandy soil, where trees were less defended, consistent with predicted feedbacks between plant community assembly and herbivore distributions. By exploring two inversely related axes of soil "quality" (abiotic stress and nutrient content), our study extends the range of mechanisms by which herbivores are known to promote edaphic specialization, illustrates how the high cost of a protection mutualism can constrain the realized niche of host trees, and shows that large-scale properties of savanna ecosystems are shaped by species interactions in cryptic ways that mimic simple abiotic determinism. These results suggest that ongoing declines in large-herbivore populations may relax spatial heterogeneity in plant assemblages and reduce the beta diversity of communities. © 2016 by the Ecological Society of America.

Distributional patterns in an insect community inhabiting a sandy beach of Uruguay

NASA Astrophysics Data System (ADS)

Mourglia, Virginia; González-Vainer, Patricia; Defeo, Omar

2015-12-01

Most studies of sandy beach macrofauna have been restricted to semiterrestrial species and do not include insects when providing species richness and abundance estimates. Particularly, spatio-temporal patterns of community structure of the entomofauna inhabiting these ecosystems have been scarcely documented. This study assessed spatio-temporal distributional patterns of the night active entomofauna on a beach-dune system of Uruguay, including variations in species richness, abundance and diversity, and their relationship with environmental factors. A deconstructive taxonomic analysis was also performed, considering richness and abundance patterns separately for the most abundant insect Orders (Hymenoptera and Coleoptera) to better understand the factors which drive their patterns. We found clear temporal and across-shore patterns in the insect community inhabiting a land-ocean interface, which matched spatiotemporal variations in the environment. Abundance and species richness were highest in spring and summer, concurrently with high temperatures and low values of sediment moisture and compaction. Multivariate ordinations showed two well-defined species groups, which separated summer, autumn and spring samples from winter ones. Generalized Linear Models allowed us to describe a clear segregation in space of the most important orders of the insect community, with specific preferences for the terrestrial (Hymenoptera) and beach (Coleoptera) fringes. Hymenoptera preferred the dune zone, characterized by high elevation and low sand moisture and compaction levels, whereas Coleoptera preferred gentle slopes and fine and humid sands of the beach. Our results suggest that beach and dune ecosystems operate as two separate components in regard to their physical and biological features. The high values of species richness and abundance of insects reveal that this group has a more significant ecological role than that originally considered so far in sandy beach ecology.

Aging effect of 137Cs obtained from 137Cs in the Kanto loam layer from the Fukushima nuclear power plant accident and in the Nishiyama loam layer from the Nagasaki A-bomb explosion.

PubMed

Ohta, Tomoko; Mahara, Yasunori; Kubota, Takumi; Igarashi, Toshifumi

2013-01-01

We measured (134)Cs and (137)Cs in the surface soil of the Kanto loam in the eastern Tokyo metropolitan area and the Nishiyama loam in Nagasaki, Japan. The observed (137)Cs deposition in the Kanto loam from the Fukushima nuclear power plant (NPP) accident ranged from 4.0 to 77 kBq m(-2), which corresponds to 0.3-5 times of that in the Nishiyama loam. The (137)Cs retardation factor in the Kanto loam obtained seven months after the Fukusima NPP accident and in the Nishiyama loam after 36 and 38 years from the detonation of the Pu atomic bomb (A-bomb) ranged from 180 to 260 and 2000 to 10,000, respectively. This difference in the retardation factors is attributed to an aging effect that corresponds to seven months and 36 to 38 years after the deposition of (137)Cs occurred on the soil minerals.

Effect of different nitrogen sources on plant characteristics and yield of common bean (Phaseolus vulgaris L.).

PubMed

Fernández-Luqueño, F; Reyes-Varela, V; Martínez-Suárez, C; Salomón-Hernández, G; Yáñez-Meneses, J; Ceballos-Ramírez, J M; Dendooven, L

2010-01-01

Wastewater sludge can be used to fertilize crops, especially after vermicomposting (composting with earthworms to reduce pathogens). How wastewater sludge or vermicompost affects bean (Phaseolus vulgaris L.) growth is still largely unknown. In this study the effect of different forms of N fertilizer on common bean plant characteristics and yield were investigated in a Typic Fragiudepts (sandy loam) soil under greenhouse conditions. Beans were fertilized with wastewater sludge, or wastewater sludge vermicompost, or urea, or grown in unamended soil, while plant characteristics and yield were monitored (the unamended soil had no fertilization). Yields of common bean plants cultivated in unamended soil or soil amended with urea were lower than those cultivated in wastewater sludge-amended soil. Application of vermicompost further improved plant development and increased yield compared with beans cultivated in wastewater amended soil. It was found that application of organic waste products improved growth and yield of bean plants compared to those amended with inorganic fertilizer.

Multi-frequency Electromagnetic Induction Survey for Archaeological Prospection: Approach and Results in Han Hangu Pass and Xishan Yang in China

NASA Astrophysics Data System (ADS)

Tang, Panpan; Chen, Fulong; Jiang, Aihui; Zhou, Wei; Wang, Hongchao; Leucci, Giovanni; de Giorgi, Lara; Sileo, Maria; Luo, Rupeng; Lasaponara, Rosa; Masini, Nicola

2018-04-01

This study presents the potential of multi-frequency electromagnetic induction (EMI) in archaeology. EMI is currently less employed for archaeological prospection with respect to other geophysical techniques. It is capable of identifying shallow subsurface relics by simultaneously measuring the apparent electrical conductivity (ECa) and apparent magnetic susceptibility (MSa). Moreover, frequency sounding is able to quantify the depths and vertical shapes of buried structures. In this study, EMI surveys with five frequencies were performed at two heritage sites with different geological conditions: Han Hangu Pass characterized by cinnamon soil and Xishan Yang by sandy loams. In the first site, high ECa values were observed with variations in depth correlated to archaeological remains. Moreover, electromagnetic anomalies related to an ancient road and five kiln caves were identified. In the second site, an ancient tomb, indicating extremely low ECa and high MSa, was discovered. Its electromagnetic properties are attributed to the cavity and ferroferric oxides.

Contribution of inorganic and organic components to sorption of neutral and ionizable pharmaceuticals by sediment/soil.

PubMed

Yamamoto, Hiroshi; Takemoto, Kohei; Tamura, Ikumi; Shin-Oka, Norihiro; Nakano, Takahiro; Nishida, Masayo; Honda, Yuta; Moriguchi, Shigemi; Nakamura, Yudai

2018-03-01

Our previous study showed that the sorption coefficient of certain polar pharmaceuticals to river sediment, especially particular amines, was unexpectedly high. Thus, we conducted sorption experiments of selected polar pharmaceuticals and pyrene derivatives, including amines, carboxylic acids, and neutral compounds, to model clay minerals, i.e., montmorillonite and kaolin, in addition to silica sands and humic substances. The contribution of each component was roughly estimated by simple fractionation of the individual sorption coefficients. Relatively high sorption coefficients (K d values) were found, especially for amines on clay minerals, which suggest that electrochemical affinity may play an important role. The estimated contribution percentage suggests a relatively large contribution from inorganic constituents, such as clay minerals, for silt loam soil; in contrast, organic components predominantly contribute for sandy river sediments. These findings could be the key to understanding not only the fate and transport but also bioavailability and environmental risks of pharmaceuticals, which are mostly polar and/or ionizable.

Inventory and vertical migration of ¹³⁷Cs in Spanish mainland soils.

PubMed

Legarda, F; Romero, L M; Herranz, M; Barrera, M; Idoeta, R; Valiño, F; Olondo, C; Caro, A

2011-06-01

In this study the total activity of (137)Cs deposited per unit area over the Spanish peninsular territory was analysed using a 150 × 150 km(2) mesh grid, with samples taken from 29 points. The deposited activities ranged between 251 and 6074 Bq/m(2). A linear relationship was obtained between these values and the mean annual rainfall at each sampling point which allowed a map to be drawn, using GIS software, which shows the distribution of total deposited (137)Cs activity across the Spanish mainland. At twelve of these sampling points the vertical migration profile of (137)Cs was obtained. These profiles are separated into two groups with different behaviour, one of which includes clay and loam soils and the other containing sandy soils. For both groups of profiles the parameters of the convective-diffusive model, which describes the vertical migration of (137)Cs in the soil, v (apparent convection velocity) and D (apparent diffusion coefficient) were calculated. Copyright © 2011 Elsevier Ltd. All rights reserved.

Fipronil mobility and transformation in undisturbed soil columns.

PubMed

Chatterjee, Niladri Sekhar; Gupta, Suman

2010-08-01

The downward movement of fipronil and its two toxic metabolites i.e. sulfone and desulfinyl were studied in undisturbed soil columns. Mobility behavior of two different formulations of fipronil viz granular and suspension concentrate were also studied. The undisturbed columns containing sandy loam soil were leached with water equivalent to 400 mm rainfall. Results revealed that although majority of the fipronil (approximately 80%) remained in top 0-5 cm layer, substantial amount (approximately 15%) moved to 5-10 cm depth. In case of metabolites sulfone and desulfinyl >90% of the residues remained in 0-5 cm core indicating low mobility of these metabolites in comparison to fipronil. Results of mobility behavior of fipronil in granular and SC formulations revealed low mobility in granular formulation. Sulfide was detected as the major degradation product in both the formulations and was found to be distributed throughout the column. A little amount of sulfone (0.1% of the total recovered) was also detected upto 10 cm depth.

Soil metabarcoding identifies season indicators and differentiators of pig and Agrostis/Festuca spp. decomposition.

PubMed

Olakanye, Ayodeji O; Ralebitso-Senior, T Komang

2018-04-15

To gain a better understanding of how environmental microbiota respond to cadaver decomposition, a forensic ecogenomic study was made with soil only control and 4g each of Sus scrofa domesticus and plant litter (Agrostis/Festuca spp.) buried individually in a sandy clay loam (80g) in sealed but perforated triplicate microcosms. The next-generation sequencing (Illumina Miseq) of the soil bacteria (16S rRNA gene) clade revealed seasonal taxomonic shifts at genus-level for the pig and plant litter microcosms compared to the non-burial controls. In particular, numerical abundances of Sphingobacterium (5.9%) and Pedobacter (24.1%) for the pig microcosms, and Rhodanobacter (18.1%) and Shinella (4.6%) for the plant litter microcosms, identified bacterial genera that could be tracked to establish a (seasonal) subsurface postmortem microbial clock. Also, family-level resolution revealed members that were unique to the control, grass and pig soils after 365 days. Copyright © 2018 Elsevier B.V. All rights reserved.

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.

Influence of Lumbricus terrestris and Folsomia candida on N2 O formation pathways in two different soils - with particular focus on N2 emissions.

PubMed

Schorpp, Quentin; Riggers, Catharina; Lewicka-Szczebak, Dominika; Giesemann, Anette; Well, Reinhard; Schrader, Stefan

2016-11-15

The gaseous N losses mediated by soil denitrifiers are generally inferred by measuring N 2 O fluxes, but should include associated N 2 emissions, which may be affected by abiotic soil characteristics and biotic interactions. Soil fauna, particularly anecic earthworms and euedaphic collembola, alter the activity of denitrifiers, creating hotspots for denitrification. These soil fauna are abundant in perennial agroecosystems intended to contribute to more sustainable production of bioenergy. Two microcosm experiments were designed to evaluate gaseous N emissions from a silty loam and a sandy soil, both provided with litter from the bioenergy crop Silphium perfoliatum (cup-plant) and inoculated with an anecic earthworm (Lumbricus terrestris), which was added alone or together with an euedaphic collembola (Folsomia candida). In experiment 1, litter-derived N flux was determined by adding 15 N-labelled litter, followed by mass spectrometric analysis of N 2 and N 2 O isotopologues. In experiment 2, the δ 18 O values and 15 N site preference of N 2 O were determined by isotope ratio mass spectrometry to reveal underlying N 2 O formation pathways. Lumbricus terrestris significantly increased litter-derived N 2 emissions in the loamy soil, from 174.5 to 1019.3 μg N 2 -N kg -1 soil, but not in the sandy soil (non-significant change from 944.7 to 1054.7 μg N 2 -N kg -1 soil). Earthworm feeding on plant litter resulted in elevated N 2 O emissions in both soils, derived mainly from turnover of the soil mineral N pool during denitrification. Folsomia candida did not affect N losses but showed a tendency to redirect N 2 O formation pathways from fungal to bacterial denitrification. The N 2 O/(N 2  + N 2 O) product ratio was predominantly affected by abiotic soil characteristics (loamy soil: 0.14, sandy soil: 0.26). When feeding on S. perfoliatum litter, the anecic L. terrestris, but not the euedaphic F. candida, has the potential to cause substantial N losses. Biotic interactions between the species are not influential, but abiotic soil characteristics have an effect. The coarse-textured sandy soil had lower gaseous N losses attributable to anecic earthworms. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Visualizing Rhizosphere Soil Structure Around Living Roots

NASA Astrophysics Data System (ADS)

Menon, M.; Berli, M.; Ghezzehei, T. A.; Nico, P.; Young, M. H.; Tyler, S. W.

2008-12-01

The rhizosphere, a thin layer of soil (0 to 2 mm) surrounding a living root, is an important interface between bulk soil and plant root and plays a critical role in root water and nutrient uptake. In this study, we used X-ray Computerized Microtomography (microCT) to visualize soil structure around living roots non-destructively and with high spatial resolution. Four different plant species (Helianthus annuus, Lupinus hartwegii, Vigna radiata and Phaseolus lunatus), grown in four different porous materials (glass beads, medium and coarse sand, loam aggregates), were scanned with 10 ìm spatial resolution, using the microtomography beamline 8.3.2 at the Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA. Sample cross section images clearly show contacts between roots and soil particles, connecting water films, air-water interfaces as well as some cellular features of the plants taproots. We found with a simulation experiment, inflating a cylindrical micro-balloon in a pack of air-dry loam aggregates, that soil fracturing rather than compaction might occur around a taproot growing in dry soil. Form these preliminary experiments, we concluded that microCT has potential as a tool for a more process-based understanding of the role of rhizosphere soil structure on soil fertility, plant growth and the water balance at the earth-atmosphere interface.

Visualizing the impact of living roots on rhizosphere soil structure using X-ray microtomography

NASA Astrophysics Data System (ADS)

Menon, M.; Berli, M.; Ghezzehei, T. A.; Nico, P.; Young, M. H.; Tyler, S. W.

2009-04-01

The rhizosphere is an interface between bulk soil and plant root and plays a critical role in root water and nutrient uptake. In this study, we used X-ray Computerized Microtomography (microCT) to visualize soil structure around living roots non-destructively and with high spatial resolution. Four different plant species (Helianthus annuus, Lupinus hartwegii, Vigna radiata and Phaseolus lunatus), grown in four different porous materials (glass beads, medium and coarse sand, loam aggregates), were scanned with 10 μm spatial resolution, using the microtomography beamline 8.3.2 at the Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA. Sample cross section images clearly show contacts between roots and soil particles, connecting water films, air-water interfaces as well as some cellular features of the plants taproots. We found with a simulation experiment, inflating a cylindrical micro-balloon in a pack of air-dry loam aggregates, that soil fracturing rather than compaction might occur around a taproot growing in dry soil. Form these preliminary experiments, we concluded that microCT has potential as a tool for a more process-based understanding of the role of rhizosphere soil structure on soil fertility, plant growth and the water balance at the earth-atmosphere interface.

Effects of traffic-induced soil compaction on crop growth and soil properties

NASA Astrophysics Data System (ADS)

Baibay, Amélia; Ren, Lidong; D'Hose, Tommy; De Pue, Jan; Ruysschaert, Greet; Cornelis, Wim

2017-04-01

Traffic-induced soil compaction on arable soils constitutes a major threat for agricultural productivity and the environmental quality of the soil, water and atmosphere. The objective of this work is to evaluate a set of prevention strategies for agricultural traffic under real farming conditions. To that end, a one-pass traffic experiment was conducted near Ghent, Belgium in winter 2015 on a sandy loam (haplic Luvisol; 43% sand, 47% silt, 10% clay). Winter rye (Secale cereale L.), which promotes the removal of residual soil nitrogen and thus reduces the potential for nitrogen leaching, was sown as cover crop using different tractor and weather settings on different field lanes: dry (D, 0.16 m3 m-3) or wet (W, 0.20-0.23 m3 m-3) conditions, normal (N, 65 cm width, axle load 8520 kg) or wide (W, 90 cm width, axle load 8520 kg) tires and high (HP, 1.4 bars for N, 1.0 bar for W) or low (LP, 1.0 bar for N, 0.5 bar for W) inflation pressure. Subsequently, crop biomass, root density and a set of hydrophysical properties (penetration resistance, saturated hydraulic conductivity and water retention at 15, 35 and 55 cm depth) were measured. Bulk density, soil quality indicators (such as air capacity) and the pore size distribution were also calculated. Results showed significant biomass reduction (p < 0.01) for trafficked plots compared to their control (un-trafficked): 40% reduction under dry conditions and ˜80% under wet conditions. However, no differences were found between traffic treatments. A similar trend was observed for root density, though less significant. Under wet conditions, the rooting depth was also reduced (10 cm instead of 30 cm), and densities were very small. These results suggest a negative effect of compaction on crop growth, worse under wet conditions, but the choice of tires did not prove to have an effect. Observations on the hydrophysical properties were more mitigated, as expected: distinct differences are primarily found under controlled lab conditions or after several passes. Moreover, high moisture conditions could not be obtained for the wet experiment, which never exceeded field capacity, conceived as threshold. Nevertheless, penetration resistance profiles indicated a plough pan about 40 cm depth, witness of previous agricultural operations on the field, and high values (3.5 to 4 MPa) were found in the subsoil too. Moreover, bulk densities were higher for all treatments (up to 1.8 Mg m-3) compared to the controls (˜1.55 Mg m-3). Saturated hydraulic conductivities were very small (<< 10 cm/d), especially for the treatments. The dry treatment also showed better values than the wet ones at 15 cm. Water retention curves tended to show decreased water content at low suctions for the treatments (mainly at 15 cm), which could reflect on a reduction of macropores and their continuity. Soil quality parameters also showed better values in the control plots. These observations support an overall compacted state and loss of structural quality, though no significant impact of the traffic experiment or prevention strategies could be drawn.

Low black carbon concentration in agricultural soils of central and northern Ethiopia.

PubMed

Yli-Halla, Markku; Rimhanen, Karoliina; Muurinen, Johanna; Kaseva, Janne; Kahiluoto, Helena

2018-08-01

Soil carbon (C) represents the largest terrestrial carbon stock and is key for soil productivity. Major fractions of soil C consist of organic C, carbonates and black C. The turnover rate of black C is lower than that of organic C, and black C abundance decreases the vulnerablility of soil C stock to decomposition under climate change. The aim of this study was to determine the distribution of soil C in different pools and impact of agricultural management on the abundance of different species. Soil C fractions were quantified in the topsoils (0-15cm) of 23 sites in the tropical highlands of Ethiopia. The sites in central Ethiopia represented paired plots of agroforestry and adjacent control plots where cereal crops were traditionally grown in clayey soils. In the sandy loam and loam soils of northern Ethiopia, the pairs represented restrained grazing with adjacent control plots with free grazing, and terracing with cereal-based cropping with adjacent control plots without terracing. Soil C contained in carbonates, organic matter and black C along with total C was determined. The total C median was 1.5% (range 0.3-3.6%). The median proportion of organic C was 85% (range 53-94%), 6% (0-41%) for carbonate C and 6% (4-21%) for black C. An increase was observed in the organic C and black C fractions attributable to agroforestry and restrained grazing. The very low concentration of the relatively stable black C fraction and the dominance of organic C in these Ethiopian soils suggest vulnerability to degradation and the necessity for cultivation practices maintaining the C stock. Copyright © 2018 Elsevier B.V. All rights reserved.

Water- and Fertilizer-Integrated Hydrogel Derived from the Polymerization of Acrylic Acid and Urea as a Slow-Release N Fertilizer and Water Retention in Agriculture.

PubMed

Cheng, Dongdong; Liu, Yan; Yang, Guiting; Zhang, Aiping

2018-05-31

To reduce the preparation cost of superabsorbent and improve the N release rate at the same time, a novel low-cost superabsorbent (SA) with the function of N slow release was prepared by chemical synthesis with neutralized acrylic acid (AA), urea, potassium persulfate (KPS), and N, N'-methylenebis(acrylamide) (MBA). The order of influence factors on the water absorbency property was determined by an orthogonal L 18 (3) 7 experiment. On the basis of the optimization results of the orthogonal experiment, the effects of a single factor on the water absorption were investigated, and the highest water absorbency (909 g/g) was achieved for the conditions of 1.0 mol urea/mol AA ratio, 100% of AA neutralized, K + , 1.5% KPS to AA mass fraction, 0.02% MBA to AA mass fraction, 45 °C reaction temperature, and 4.0 h reaction time. The optimal sample was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Swelling behaviors of the superabsorbent were investigated in distilled water and various soil and salt solutions. The water-release kinetics of SA in different negative pressures and soils were systematically investigated. Additionally, the maize seed germination in various types of soil with different amounts of SA was proposed, and the N could release 3.71% after being incubated in distilled water for 40 days. After 192 h, the relative water content of SA-treated sandy loam, loam, and paddy soil were 42, 56, and 45%, respectively. All of the results in this work showed that SA had good water retention and slow N-release properties, which are expected to have potential applications in sustainable modern agriculture.

Aeolian cliff-top deposits and buried soils in the White River Badlands, South Dakota, USA

USGS Publications Warehouse

Rawling, J. E.; Fredlund, G.G.; Mahan, S.

2003-01-01

Aeolian deposits in the North American Great Plains are important sources of Holocene palaeo-environmental records. Although there are extensive studies on loess and dune records in the region, little is known about records in aeolian cliff-top deposits. These are common on table (mesa) edges in the White River Badlands. These sediments typically have loam and sandy-loam textures with dominantly very fine sand, 0.5-1% organic carbon and 0.5-5% CaCO3. Some of these aeolian deposits are atypically coarse and contain granules and fine pebbles. Buried soils within these deposits are weakly developed with A-C and A-AC-C profiles. Beneath these are buried soils with varying degrees of pedogenic development formed in fluvial, aeolian or colluvial deposits. Thickness and number of buried soils vary. However, late-Holocene soils from several localities have ages of approximately 1300, 2500 and 3700 14C yrs BP. The 1300 14C yr BP soil is cumulic, with a thicker and lighter A horizon. Soils beneath the cliff-top deposits are early-Holocene (typically 7900 but as old as 10000 14C yrs BP) at higher elevation (???950 m) tables, and late-Holocene (2900 14C yrs BP) at lower (???830 m) tables. These age estimates are based on total organic matter 14C ages from the top 5 cm of buried soils, and agreement is good between an infrared stimulated luminescence age and bracketing 14C ages. Our studies show that cliff-top aeolian deposits have a history similar to that of other aeolian deposits on the Great Plains, and they are another source of palaeoenvironmental data.

Effect of vermicompost on soil fertility and crop productivity--beans (Phaseolus vulgaris).

PubMed

Manivannan, S; Balamurugan, M; Parthasarathi, K; Gunasekaran, G; Ranganathan, L S

2009-03-01

Field experiments were conducted at Sivapuri, Chidambaram, Tamil Nadu to evaluate the efficacy of vermicompost, in comparison to inorganic fertilizers-NPK, on the physio-chemical and biological characteristics of the soils--clay loam soil (CLS) and sandy loam soil (SLS) and on the growth, yield and nutrient content of beans--Phaseolus vulgaris. Results showed that the application of vermicompost @ 5 tonnes ha(-1) had enhanced significantly the pore space (1.09 and 1.02 times), water holding capacity (1.1 and 1.3 times), cation exchange capacity (1.2 and 1.2 times). It reduced particles (1.2 and 1.2 times), and bulk density (1.2 and 1.2 times), pH (1 and 1.02 times) and electrical conductivity (1.4 and 1.2 times) and increased organic carbon (37 and 47 times), micro (Ca 3.07 and 1.9 times, Mg 1.6 and 1.6 times, Na 2.4 and 3.8 times, Fe 7 and 7.6 times, Mn 8.2 and 10.6 times, Zn 50 and 52 times and Cu 14 and 22 times) and macro (N 1.6 and 1.7 times, P 1.5 and 1.7 times, K 1.5 and 1.4 times) nutrients and microbial activity (1.4 and 1.5 times) in both soil types, particularly more in CLS. The growth, yield (1.6 times) and quality (protein (1.05 times) and sugar (1.01 times) content in seed) of bean were enhanced in CLS than SLS. On the other hand, the application of inorganic fertilizers @ 20:80:40 kg ha(-1) has resulted in reduced porosity (1.03 and 1.01 times), organic carbon (1.04 and 9.5 times) and microbial activity (1.02 and 1.03 times) in both soil types.

Perfluorooctane sulfonate in surface soils: Effects on reproduction in the collembolan, Folsomia candida, and the oribatid mite, Oppia nitens.

PubMed

Princz, Juliska; Jatar, Muriel; Lemieux, Heather; Scroggins, Rick

2018-06-04

Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant, which has been detected at significant concentrations in soils at sites used for fire-fighting training operations. Recent ecotoxicological research has mainly focused on earthworms to assess the toxicity of PFOS in soil. However, the inclusion of other soil taxonomic groups allow for a more holistic estimate of contaminant risk, including the derivation of more comprehensive soil quality guidelines. The present study assessed the toxicity of PFOS using the collembolan, Folsomia candida, and the oribatid mite, Oppia nitens, in two types of soil: a coarse-textured sandy loam (VSL) and fine-textured clay loam (NRS). As a standard O. nitens reproduction test is being formalized, the results of the study were also used to compare sensitivity across test species. Effects were soil dependent, with test species being 2-4 times more susceptible to PFOS in VSL, relative to NRS, likely due to differences in organic matter and clay content. Oppia nitens was significantly more sensitive to PFOS, regardless of soil type, in comparison to F. candida. The IC50s for reproduction for O. nitens were 23 mg kg -1 (95% confidence interval: 17-32 mg kg -1 ) in the VSL and 95 mg kg -1 (69-134 mg kg -1 ) in the NRS, and for F. candida were 94 mg kg -1 (72-122 mg kg -1 ) in the VSL and 233 mg kg -1 (177-306 mg kg -1 ) in the NRS. The present study demonstrates the application and inclusion of the oribatid mite, O. nitens, for the risk assessment of contaminants in soil. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

Occurrence of Phytophthora plurivora and other Phytophthora species in oak forests of southern Poland and their association with site conditions and the health status of trees.

PubMed

Jankowiak, R; Stępniewska, H; Bilański, P; Kolařík, M

2014-11-01

Phytophthora plurivora and other Phytophthora species are known to be serious pathogens of forest trees. Little is known, however, about the presence of P. plurivora in Polish oak forests and their role in oak decline. The aims of this study were to identify P. plurivora in healthy and declining Quercus robur stands in southern Poland and to demonstrate the relationship between different site factors and the occurrence of P. plurivora. In addition, the virulence of P. plurivora and other Phytophthora species was evaluated through inoculations using 2-year-old oak seedlings. Rhizosphere soil was investigated from 39 oak stands representing different healthy tree statuses. The morphology and DNA sequences of the internal transcribed spacer regions (ITS) of the ribosomal DNA and the mitochondrial cox1 gene were used for identifications. P. plurivora, an oak fine root pathogen, was isolated from rhizosphere soil samples in 6 out of 39 stands. Additionally, Phytophthora cambivora, Phytophthora polonica and Phytophthora rosacearum-like were also obtained from several stands. The results showed a significant association between the presence of P. plurivora and the health status of oak trees. Similar relationships were also observed for all identified Phytophthora species. In addition, there was evidence for a connection between the presence of all identified Phytophthora species and some site conditions. Phytophthora spp. occurred more frequently in declining stands and in silt loam and sandy loam soils with pH ≥ 3.66. P. plurivora and P. cambivora were the only species capable of killing whole plants, producing extensive necrosis on seedling stems.

Range expansion potential of two co-occurring invasive vines to marginal habitats in Turkey

NASA Astrophysics Data System (ADS)

Farooq, Shahid; Tad, Sonnur; Onen, Huseyin; Gunal, Hikmet; Caldiran, Ugur; Ozaslan, Cumali

2017-10-01

Niche distribution models accurately predict the potential distribution range of invasive plants into new habitats based on their climatic requirements in the native regions. However, these models usually ignore the marginal habitats which can limit the distribution of exotic plants. We therefore tested the seedling survival, growth and nutrient acquisition capabilities of two co-occurring invasive vines [Persicaria perfoliata (L.) H. Gross and Sicyos angulatus L.] in three different manipulative greenhouse experiments to infer their range expansion potential to marginal habitats in Turkey. First experiment included five different moisture availability regimes (100, 75, 50, 25 and 12.5% available water), second experiment consisted of four different salinity levels (0, 3, 6 and 12 dSm-1 soil salinity) and third experiment had four different soil textures (clay-1, clay-2, sandy loam and silt-clay-loam). Seedling mortality was only observed under extreme moisture deficiency in both plant species, while most of the transplanted seedlings of both species did not survive under 6 and 12 dSm-1 salinity levels. Soil textures had no effect on seedling survival. POLPE better tolerated low moisture availability and high salinity compared to SIYAN. Biomass production in both plant species was linearly reduced with increasing salinity and moisture deficiency. SIYAN invested more resources towards shoot, accumulated higher K and P, whereas POLPE maintained higher root-to-shoot ratio under all experimental conditions. Both plant species employed different strategies to cope with adverse environmental conditions, but failed to persist under high soil salinity and moisture deficiency. Our study suggest that both plant species have limited potential of range expansion to marginal habitats and will be limited to moist and humid areas only. Therefore, further research activities should be concentrated in these regions to develop effective management strategies against both species.

Physicochemical properties of soils in the sago palm (Metroxylon spp.) growing area of Surat Thani province Thailand

NASA Astrophysics Data System (ADS)

Ruairuen, W.; Sparrow, E. B.; Fochesatto, G. J.

2016-12-01

Sago palm is one of the most important plants for sustainable agriculture and rural development in tropical swampy and peaty soils. Where no major crops can grow without drainage or soil improvement. It stores large quantities of starch which can be further processed into various basic raw materials for food, animal feed, industrial uses and alternative energy. This study aims to investigate the physicochemical properties of soil across the sago palm growing areas at Surat Thani province Thailand, where major of sago palms growth naturally exists. The soil samples from three districts Khiri Rat Nikhom (KR; 9 sampling sites), Kanchanadit (KD; 5 sampling sites), and Khian Sa (KS; 2 sampling sites) were studied and compared at 0-15 cm depth during March to June 2016. Observations indicated that the physicochemical properties of soil varied in each growing area. Soil bulk densities averages were lower in KD (0.52 g cm-3) than those in KR (0.58 g cm-3) and KS (0.57 g cm-3). Soil texture around KD and KS were dominated by silty loam. While in KR soil texture was dominated by sandy loam. The average soil conductivity in KS (5.68 mS m-1) was higher than KR (2.62 mS m-1) and KD (1.65 mS m-1). Furthermore, we found the sago palms grow well in a range of soil pH from 5.52 to 7.15, average soil pH: KS (6.8) and KD (6.96), while acid in KR (5.84). We also discuss the conservation activities to adequately protect sago palm, most of which are significantly threatened by habitat destruction and unsustainable harvesting.

Simulating the fate of water in field soil crop environment

NASA Astrophysics Data System (ADS)

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

2005-12-01

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

Environmental factors determining the trace-level sorption of silver and thallium to soils.

PubMed

Jacobson, Astrid R; McBride, Murray B; Baveye, Philippe; Steenhuis, Tammo S

2005-06-01

Silver (Ag) and thallium (Tl) are nonessential elements that can be highly toxic to a number of biota even when present in the environment at trace levels. In spite of that, the literature on the chemistry and fate of Ag and Tl in soils is extremely scanty. In that context, the key objective of this research was to compare the sorption characteristics of trace amounts of Ag and Tl on a range of soils and minerals. A second objective was to determine the extent to which the composition and surface chemistry of the sorbents, as well as other environmental factors (simulated acid rain application and the presence of competing ions like K+ and NH4+) influence the sorption and lability of Ag and Tl. To this end, short-term and long-term sorption isotherms were generated under batch conditions for trace levels of Ag and Tl onto three illite-rich mineral soils from central New York (silt loam and fine sandy loam), a peaty-muck soil drained for agricultural use, and soil minerals (ferrihydrite and birnessite). Silver sorbed more strongly than thallium to all the soils. The peaty-muck soil sorbed Ag more strongly than the mineral soils, confirming that silver sorption to soils is dominated by soil organic matter either through exchange or complexation. The organic matter-rich soil's retention of Tl, however, was similar to that of the sandy soil. Amounts of Ag and Tl sorbed to the mineral soils increased after a 1-year incubation period. Whereas Ag sorption to the peaty-muck soil also increased with time, Tl sorption was unaffected. Short batch studies indicated that high amounts of Tl sorb to birnessite (30% by mass). However, subsequent X-ray diffraction (XRD) analysis of the solid did not detect the presence of any Tl3+ as Tl2O3 on the MnO4. In contrast, TlI was relatively poorly sorbed on noncrystalline ferrihydrite at pH 5.1 (1.5% by mass). Thus, Mn oxides may play a role in Tl retention by soils; whereas, contrary to previous reports, iron oxides do not effectively sorb Tl. Acid rain and addition of potassium (K+) and ammonium (NH4+) as competing ions had no long-term effect on Ag or Tl sorption. Thallium remaining in the all the batch sorption solutions, as determined by flame atomic absorption spectroscopy (FAAS) and differential pulse anodic stripping voltametry (DPASV), was completely labile, which may have important environmental consequences.

Macroaggregation and soil organic carbon restoration in a highly weathered Brazilian Oxisol after two decades under no-till.

PubMed

de Oliveira Ferreira, Ademir; de Moraes Sá, João Carlos; Lal, Rattan; Tivet, Florent; Briedis, Clever; Inagaki, Thiago Massao; Gonçalves, Daniel Ruiz Potma; Romaniw, Jucimare

2018-04-15

Conclusions based on studies of the impacts of soil organic carbon (SOC) fractions and soil texture on macroaggregation and SOC stabilization in long-term (>20years) no-till (NT) fields remain debatable. This study was based on the hypothesis that the amount and frequency of biomass-C input associated with NT can be a pathway to formation of macroaggregates and to SOC buildup. The objectives were to: 1) assess the macroaggregate distribution (proportional mass, class mass) and the SOC and particulate organic carbon (POC) stocks of extra-large (8-19mm), large (2-8mm) and small (0.25-2mm) macroaggregate size classes managed for two decades by NT, and 2) assess the recovery of SOC stocks in extra-large macroaggregates compared to adjacent native vegetation (Andropogon sp., Aristida sp., Paspalum sp., and Panicum sp.). The crop rotation systems were: soybean (Glycine max L.), maize (Zea mays L.) and beans (Phaseolus vulgaris L.) in summer; and black oat (Avena strigosa Schreb), white oat (Avena sativa), vetch (Vicia sativa L.), black oat.+vetch (Avena strigosa Schreb+vetch) and wheat (Triticum aestivum L.) in winter. The experimental was laid out as 2×2 randomized block factorial with 12 replicates of a NT experiment established in 1997 on two highly weathered Oxisols. The factors comprised of: (a) two soil textural types: clay loam and sandy clay, and (b) two sampling depths: 0-5 and 5-20cm. The three classes of macroaggregates were obtained by wet sieving, and the SOC content was determined by the dry combustion method. The extra-large macroaggregate classes in 0-20cm depth for sandy clay (SdC) and clay loam (CL) Oxisol represented 75.2 and 72.4% of proportional mass, respectively. The SOC and POC stocks among macroaggregate classes in 0-5 and 5-20cm depths decreased in the order: 8-19mm>2-8mm ≈ 0.25-2mm. The SdC plots under soybean/maize at 3:1 ratio recovered 58.3%, while those at 1:1 ratio (high maize frequency) in CL recovered 73.1% of SOC stock in the extra-large macroaggregates compared with the same under native vegetation for 0-20cm depth. Thus, partial restoration of the SOC stock in original extra-large macroaggregate confirms the hypothesis that NT through higher maize cultivation frequency can be a pathway to fomation of macroaggregates and SOC buildup. Copyright © 2017 Elsevier B.V. All rights reserved.

Reformulation of the CBR Procedure. Report 1: Basic Report

DTIC Science & Technology

2012-04-01

originate a superior method of compaction control, the modified density test associated with the name of Ralph R. Proctor . In time, Porter was able to...enough for the subsoil moisture to equalize. Colonel Bragdon in the South Atlantic Division was to choose an airstrip built on sandy clay , a fairly good...subsoil; Colonel Scott in the Southwestern Division, one of lean black clay , a rather poor foundation; Colonel Elliott in the Upper Mississippi

An environmental assessment and risk map of Ascaris lumbricoides and Necator americanus distributions in Manufahi District, Timor-Leste

PubMed Central

Wardell, Rebecca; Clements, Archie C. A.; Lal, Aparna; Summers, David; Llewellyn, Stacey; Campbell, Suzy J.; McCarthy, James; Gray, Darren J.; V. Nery, Susana

2017-01-01

Background In Timor-Leste there have been intermittent and ineffective soil-transmitted helminth (STH) deworming programs since 2004. In a resource-constrained setting, having information on the geographic distribution of STH can aid in prioritising high risk communities for intervention. This study aimed to quantify the environmental risk factors for STH infection and to produce a risk map of STH in Manufahi district, Timor-Leste. Methodology/Principal findings Georeferenced cross-sectional data and stool samples were obtained from 2,194 participants in 606 households in 24 villages in the Manufahi District as part of cross sectional surveys done in the context of the “WASH for Worms” randomised controlled trial. Infection status was determined for Ascaris lumbricoides and Necator americanus using real-time quantitative polymerase chain reaction. Baseline infection data were linked to environmental data obtained for each household. Univariable and multivariable multilevel mixed-effects logistic regression analysis with random effects at the village and household level were conducted, with all models adjusted for age and sex. For A. lumbricoides, being a school-aged child increased the odds of infection, whilst higher temperatures in the coolest quarter of the year, alkaline soils, clay loam/loam soils and woody savannas around households were associated with decreased infection odds. For N. americanus, greater precipitation in the driest month, higher average enhanced vegetation index, age and sandy loam soils increased infection odds, whereas being female and living at higher elevations decreased the odds of infection. Predictive risk maps generated for Manufahi based upon these final models highlight the high predicted risk of N. americanus infection across the district and the more focal nature of A. lumbricoides infection. The predicted risk of any STH infection is high across the entire district. Conclusions/Significance The widespread predicted risk of any STH infection in 6 to 18 year olds provides strong evidence to support strategies for control across the entire geographical area. As few studies include soil texture and pH in their analysis, this study adds to a growing body of evidence suggesting these factors influence STH infection distribution. This study also further supports that A. lumbricoides prefers acidic soils, highlighting a potential relatively unexplored avenue for control. Trial registration ClinicalTrials.gov ACTRN12614000680662. PMID:28489889

Factors affecting trace element content in periurban market garden subsoil in Yunnan Province, China.

PubMed

Zu, Yanqun; Bock, Laurent; Schvartz, Christian; Colinet, Gilles; Li, Yuan

2011-01-01

Field investigations were conducted to measure subsoil trace element content and factors influencing content in an intensive periurban market garden in Chenggong County, Yunnan Province, South-West China. The area was divided into three different geomorphological units: specifically, mountain (M), transition (T) and lacustrine (L). Mean trace element content in subsoil were determined for Pb (58.2 mg/kg), Cd (0.89 mg/kg), Cu (129.2 mg/kg), and Zn (97.0 mg/kg). Strong significant relationships between trace element content in topsoil and subsoil were observed. Both Pb and Zn were accumulated in topsoil (RTS (ratio of mean trace element in topsoil to subsoil) of Pb and Zn > or =1.0) and Cd and Cu in subsoil (RTS of Cd and Cu < or = 1.0). Subsoil trace element content was related to relief, stoniness, soil color, clay content, and cation exchange capacity. Except for 7.5 YR (yellow-red) color, trace element content increased with color intensity from brown to reddish brown. Significant positive relationships were observed between Fe content and that of Pb and Cu. Trace element content in mountain unit subsoil was higher than in transition and lacustrine units (M > T > L), except for Cu (T > M > L). Mean trace element content in calcareous subsoil was higher than in sandstone and shale. Mean trace element content in clay texture subsoil was higher than in sandy and sandy loam subsoil, and higher Cu and Zn content in subsoil with few mottles. It is possible to model Pb, Cd, Cu, and Zn distribution in subsoil physico-chemical characteristics to help improve agricultural practice.

Reductive immobilization of chromate in water and soil using stabilized iron nanoparticles.

PubMed

Xu, Yinhui; Zhao, Dongye

2007-05-01

Laboratory batch and column experiments were conducted to investigate the feasibility of using a new class of stabilized zero-valent iron (ZVI) nanoparticles for in situ reductive immobilization of Cr(VI) in water and in a sandy loam soil. Batch kinetic tests indicated that 0.08g/L of the ZVI nanoparticles were able to rapidly reduce 34mg/L of Cr(VI) in water at an initial pseudo first-order rate constant of 0.08h(-1). The extent of Cr(VI) reduction was increased from 24% to 90% as the ZVI dosage was increased from 0.04 to 0.12g/L. The leachability of Cr preloaded in a Cr-loaded sandy soil was reduced by nearly 50% when the soil was amended with 0.08g/L of the ZVI nanoparticles in batch tests at a soil-to-solution ratio of 1g: 10mL. Column experiments indicated that the stabilized ZVI nanoparticles are highly deliverable in the soil column. When the soil column was treated with 5.7 bed volumes of 0.06g/L of the nanoparticles at pH 5.60, only 4.9% of the total Cr was eluted compared to 12% for untreated soil under otherwise identical conditions. The ZVI treatment reduced the TCLP leachability of Cr in the soil by 90%, and the California WET (Waste Extraction Test) leachability by 76%. The stabilized ZVI nanoparticles may serve as a highly soil-dispersible and effective agent for in situ reductive immobilization of chromium in soils, groundwater, or industrial wastes.

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.

Altering recharge dynamics through woody vegetation removal: a study on the Carrizo-Wilcox aquifer of south Texas

NASA Astrophysics Data System (ADS)

Mattox, A. M.

2011-12-01

Grasslands in many semi-arid regions of the world have seen an expansion of woody vegetation over the past century and many now exist largely as woodlands or shrublands. This "woody encroachment" results in numerous changes to ecosystem function, including alteration of element and water cycles. As in many parts of the world, these shrublands in south Texas have been subjected to a variety of management practices intended to reduce woody vegetation and increase the dominance of herbaceous vegetation. In addition to the intended change in vegetation structure, this activity has the potential to affect hydrologic fluxes and potentially increase deep drainage through reduced transpiration and rooting depths. However, there is significant uncertainty about the hydrologic response of vegetation to woody vegetation removal. We report here the results of a large manipulative experiment designed to assess the effects of woody vegetation removal on soil moisture movement in the vadose zone in an area that serves as a recharge zone for an unconsolidated sediment aquifer (Carrizo-Wilcox). In this study woody vegetation has been removed using a mechanical method (roller chopping) as well as a mechanical and chemical method (chainsaw removal + stump herbicide). The treated plots are located on three different soil types that represent the range of soils typical in this area. A water balance approach is used to assess soil moisture fluxes and potential deep drainage. In this first year of the study we quantified ecological and edaphic components that have the greatest effect on deep drainage, namely rooting depth, soil texture and antecedent soil water conditions. Exceptionally dry conditions this year have provided a unique opportunity to understand plant soil water interactions in the critical zone given the strong soil moisture limitations observed in the surface soil horizons. Understanding these interactions across different plant communities and soil textures are the initial steps to determining if ground water recharge may be increased through brush management. Rooting depth and volumetric water content were determined in the Chacon clay loam, Webb sandy loam and Antosa-Bobillo loamy sands. Two soil cores were taken to depths of 2 m in each of the 1/4 acre plots in each of the treated and untreated plots for a total of 54 cores. Rooting depths were determined through a combination of hydro-pneumatic root elutriation, comparison of soil water profiles in treated and untreated plots, as well as stem and soil water isotope analysis. Initial data indicates hydraulic redistribution is occurring in the loamy sand as well as the clay loam soils. Neutron probe measurements suggest that vegetation may be facilitating the movement of water into deeper soil horizons in the clay loam soils. In addition to improving our understanding of the relationships between vegetation structure and vadose zone hydrology, our results will be useful for managing water resources under increasing demand, climate change, and varied priorities for entities tasked with managing water resources.

Emergence and growth of plant species in coal mine soil

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

Day, A.D.; Mitchell, G.F.; Tucker, T.C.

1979-01-01

Experiments were conducted in the laboratory and greenhouse in Arizona with the following objectives: to evaluate the chemical properties of undisturbed soil, surface-mined coal land (coal mine soil) on the Black Mesa Coal Mine, and Gila loam soil; and to study the emergence of seven plant species in the greenhouse in Gila loam soil and coal mine soil. The pH of coal mine soil (6.2) was lower than the pH of undisturbed soil (7.5) or Gila loam (7.6). The total soluble salts in coal mine soil (3241) and undisturbed soil (4592) were much higher than in Gila loam (378); however,more » coal mine soil was lower in total soluble salts than undisturbed soil. The nitrogen content of coal mine soil was higher than the nitrogen content of undisturbed soil or gila loam. Emergence percentages for seven plant species grown in coal mine soil were similar to emergence percentages for the same species grown in Gila loam. Alfalfa (Medicago sativa L.), barley (Hordeum vulgare L.), and wheat (Triticum aestivum L. em Thell.) had from 84 to 93% emergence in coal mine soil. Indian ricegrass (Oryzopsis hymenoides Roem. and Shult), fourwing saltbush (Atriplex canescens Pursh), yellow sweetclover (Melilotus officinalis Lam.), and winterfat (Euroti lanata Pursh.) emerged <35% in coal mine soil and Gila loam. Plant growth data from forage species grown in the greenhouse indicate that coal mine soil has a lower fertility level than does Gila loam soil. When supplied with optimum soil moisture and plant nutrients, coal mine soil produced approximately the same yields of forage from alfalfa, barley, and wheat as were produced in Gila loam under the same soil-moisture and fertility conditions.« less

Increase in Dry Weight and Total Nitrogen Content in Zea mays and Setaria italica Associated with Nitrogen-fixing Azospirillum spp. 1

PubMed Central

Cohen, Efraim; Okon, Yaacov; Kigel, Jaime; Nur, Israel; Henis, Yigal

1980-01-01

The association between nitrogen-fixing bacteria from the genus Azospirillum and the grasses Zea mays and Setaria italica was investigated in sterilized Leonard-jar assemblies. Nitrogen-fixing bacteria isolated from Cynodon dactylon roots in Israel and Azospirillum brasilense (Sp-7, Sp-80, and Cd) were examined. C2H2 reduction activity was detected in systems containing 0.0 to 0.08 but not in those containing 0.16 gram per liter NH4NO3. The organisms tested significantly increased plant dry weight (50-100%), total N content of leaves (50-100%) and C2H4 production (300-1000 nanomoles C2H4 per plant per hour). Highest C2H2 reduction activities were obtained above 30 C and with high light intensities. Significant increases in S. italica dry weight (DW) and nitrogen (N) content were observed in sand (DW = 80%, N = 150%), sandy loam soil (DW = 80%, N = 75%) and loess (DW = 37%, N = 25%). The results obtained in this work clearly demonstrate the potential benefit of inoculating grasses with Azospirillum. PMID:16661514

Metal concentrations in aquatic macrophytes as influenced by soil and acidification

USGS Publications Warehouse

Sparling, D.W.; Lowe, T.P.

1998-01-01

Bioavailability of metals to aquatic plants is dependent on many factors including ambient metal concentration, pH of soil or water, concentration of ligands, competition with other metals for binding sites, and mode of exposure. Plants may be exposed to metals through water, air, or soil, depending on growth form. This paper examines the influence of soil type under two regimens of water acidification on metal uptake by four species of aquatic macrophytes: smartweed (Polygonum sagittatum), burreed (Sparganium americanum), pondweed (Potamogeton diversifolius), and bladderwort (Utricularia vulgaris) in constructed, experimentally acidified wetlands. Soil types consisted of a comparatively high-metal clay or a lower-metal sandy loam. Each pond was either acidified to pH ca. 4.85.3 or allowed to remain circumneutral. Metal concentrations tended to be higher in the submerged bladderwort and pondweed than in the emergent burreed and smartweed. Soils were important to plant metal concentrations in all species, but especially in the emergents. Acidification influenced plant concentrations of some metals and was especially important in the submerged pondweed. Bioaccumulation of metals occurred for Mn, B, Sr, Ba, and Zn, compared to soil concentrations.

Study on Correlation Between Shear Wave Velocity and Ground Properties for Ground Liquefaction Investigation of Silts

NASA Astrophysics Data System (ADS)

Che, Ailan; Luo, Xianqi; Qi, Jinghua; Wang, Deyong

Shear wave velocity (Vs) of soil is one of the key parameters used in assessment of liquefaction potential of saturated soils in the base with leveled ground surface; determination of shear module of soils used in seismic response analyses. Such parameter can be experimentally obtained from laboratory soil tests and field measurements. Statistical relation of shear wave velocity with soil properties based on the surface wave survey investigation, and resonant column triaxial tests, which are taken from more than 14 sites within the depth of 10 m under ground surface, is obtained in Tianjin (China) area. The relationship between shear wave velocity and the standard penetration test N value (SPT-N value) of silt and clay in the quaternary formation are summarized. It is an important problem to research the effect of shear wave velocity on liquefaction resistance of saturated silts (sandy loams) for evaluating liquefaction resistance. According the results of cyclic triaxial tests, a correlation between liquefaction resistance and shear wave velocity is presented. The results are useful for ground liquefaction investigation and the evaluation of liquefaction resistance.

Biogenic nitric oxide from wastewater land application

NASA Astrophysics Data System (ADS)

Rammon, Desirée A.; Peirce, J. Jeffrey

The importance of municipal wastewater land application to nitric oxide production and transport in soil was studied through the formulation and conduct of a comprehensive laboratory testing protocol. Nitric oxide (NO) is a precursor in the formation of tropospheric ozone which can directly impact public health and the environment. It is the uncertainty in the NO budget, and its relation to O 3, that motivates the need for measurements and modeling of NO flux from soils. Wastewater-amended soil is potentially one important component of that budget. NO emissions reported here were measured from: a well-characterized unamended soil, water-amended soil, and wastewater-amended soil in the laboratory in a dynamic test chamber. Laboratory results indicate that NO emissions from the selected sandy loam soil ranged from 0.3 to 0.4 ng N m -2 s -1 per cm 2 of unamended soil, while water-amended soil emissions ranged from 0.4 to 0.7 ng N m -2 s -1 per cm 2. NO flux from wastewater-amended soil ranged from 1.0 to 1.2 ng N m -2 s -1 per cm 2 of applied soil.

Sorption and leaching of benzalkonium chlorides in agricultural soils.

PubMed

Khan, Adnan Hossain; Macfie, Sheila M; Ray, Madhumita B

2017-07-01

The adsorption and leaching characteristics of two commonly used benzalkonium chlorides (BACs), benzyl dimethyl dodecyl ammonium chloride (BDDA) and benzyl dimethyl tetradecyl ammonium chloride (BDTA) using three agricultural soils with varied proportions of silt, sand, clay, and organic matter were determined. BACs are cationic surfactants used in large quantities for sanitary and personal care products and are abundant in environmental samples. Adsorption isotherm data (aqueous concentration in the range of 25-150 mg L -1 ) fitted the Langmuir model better than the Freundlich model. BDTA with a longer alkyl chain adsorbed more to soil compared to BDDA, and the soil with the highest percentage of clay adsorbed the most. Column tests conducted using soils amended with lime stabilised biosolids and artificial rain water at a flow rate of 0.2 mL min -1 indicate very low leaching of BACs. Less than 1% of the available BDDA leached through sandy loam soil column with a depth of 9 cm. Therefore, the possibility of BACs to become bioavailable through leaching is very low at environmentally relevant concentrations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Soybean Photosynthesis and Yield as Influenced by Heterodera glycines, Soil Type and Irrigation.

PubMed

Koenning, S R; Barker, K R

1995-03-01

The effects of soil types and soil water matric pressure on the Heterodera glycines-Glycine max interaction were examined in microplots in 1988 and 1989. Reproduction of H. glycines was restricted in fine-textured soils as compared with coarse-textured ones. Final population densities of this pathogen in both years of the study were greater in nonirrigated soils than in irrigated soils. The net photosynthetic rate of soybean (per unit area of leaf) was suppressed only slightly or not at all in response to infection by H. glycines and other stresses. Relative soybean-yield suppression in response to H. glycines was not affected by water content in fine-textured soils, but slopes of the damage functions were steepest in sand, sandy loam, and muck soils at high water content (irrigated plots). Yield restriction of soybean in response to this pathogen under irrigation was equal to or greater than the yield suppression under dry conditions. Although yield potential may be elevated by irrigation when soil-water content is inadequate, supplemental irrigation cannot be used to circumvent nematode damage to soybean.

Distribution of total and fecal coliform organisms from septic effluent in selected coastal plain soils.

PubMed Central

Reneau, R B; Pettry, D E; Shanholtz, M I; Graham, S A; Weston, C W

1977-01-01

Distribution of total and fecal coliform bacteria in three Atlantic coastal plain soils in Virginia were monitored in situ over a 3-year period. The soils studied were Varina, Goldsboro, and Beltsville sandy loams. These and similar soils are found extensively along the populous Atlantic seaboard of the United States. They are considered only marginally suitable for septic tank installation because the restricting soil layers result in the subsequent development of seasonal perched water tables. To determine both horizontal and vertical movement of indicator organisms, samples were collected from piezometers placed at selected distances and depths from the drainfields in the direction of the ground water flow. Large reductions in total and fecal coliform bacteria were noted in the perched ground waters above the restricting layers as distance from the drainfield increased. These restricting soil layers appear to be effective barriers to the vertical movement of indicator organisms. The reduction in the density of the coliform bacteria above the restricting soil layers can probably be attributed to dilution, filtration, and dieoff as the bacteria move through the natural soil systems. PMID:325589

Effect of soil type and exposure duration on mortality and transfer of chlorantraniliprole and fipronil on Formosan subterranean termites (Isoptera: Rhinotermitidae).

PubMed

Gautam, Bal K; Henderson, Gregg

2011-12-01

The uptake and potential transfer of chlorantraniliprole and fipronil by the Formosan subterranean termite, Coptotermes formosanus Shiraki, was investigated in the laboratory by using donor-recipient model bioassays. Two different types of substrates, sandy loam soil (18.6% organic matter) and sand (0.19% organic matter), were used to evaluate how these treated substrates impact the direct mortality and transfer efficiency of the two nonrepellent termiticides tested at different concentrations. Chlorantraniliprole exhibited a more delayed mortality on termites than fipronil in sand. In soil, chlorantraniliprole did not cause higher mortality to either donor or recipient termite at any of the tested concentrations during a 21-d test period when compared with controls. Compared with the controls, a greater number of donors died in the soil treated with fipronil at 14 h postinteraction, and higher death of recipients occurred at 21 d but only in the 60-ppm concentration tested. Our data showed that chlorantraniliprole performed best in substrate with low organic matter against

Impact of azadirachtin, an insecticidal allelochemical from neem on soil microflora, enzyme and respiratory activities.

PubMed

Gopal, Murali; Gupta, Alka; Arunachalam, V; Magu, S P

2007-11-01

The effect of 10% azadirachtin granules (alcoholic extract of neem seed kernel mixed with China clay) was studied on the population of bacteria, actinomycetes, fungi, Azotobacter and nitrifying bacteria; soil dehydrogenase, phosphatase and respiratory activities on 0, 15th, 30th, 60th and 90th days after application in sandy loam soil collected from the fields. It was observed that baring the Azotobacter sp., azadirachtin at all the doses exerted a suppressive effect on the rest of the microbial communities and enzyme activities in the initial 15 day period. The population of bacteria, actinomycetes besides phosphatase and respiratory activities recovered after 60th day and subsequently increased significantly. The fungi and nitrifiers were most sensitive groups as their numbers were reduced significantly throughout the studies. The two times and five times recommended dose of azadirachtin had very high biocidal effects on the soil microorganisms and its activities. However, analysis of the data by the Shannon Weaver index showed that azadirachtin reduces both the form and functional microbial diversity at all doses.

Influence of the Soil Genesis on Physical and Mechanical Properties

PubMed Central

Marschalko, Marian; Yilmaz, Işık; Fojtová, Lucie; Kubečka, Karel; Bouchal, Tomáš; Bednárik, Martin

2013-01-01

The paper deals with the influence of soil genesis on the physical-mechanical properties. The presented case study was conducted in the region of the Ostrava Basin where there is a varied genetic composition of the Quaternary geological structure on the underlying Neogeneous sediments which are sediments of analogous granulometry but different genesis. In this study, 7827 soil samples of an eolian, fluvial, glacial, and deluvial origin and their laboratory analyses results were used. The study identified different values in certain cases, mostly in coarser-grained foundation soils, such as sandy loam S4 (MS) and clayey sand F4 (CS). The soils of the fluvial origin manifest different values than other genetic types. Next, based on regression analyses, dependence was proved neither on the deposition depth (depth of samples) nor from the point of view of the individual foundation soil classes or the genetic types. The contribution of the paper is to point at the influence of genesis on the foundation soil properties so that engineering geologists and geotechnicians pay more attention to the genesis during engineering-geological and geotechnical investigations. PMID:23844398

Soil Moisture Retrieval Through Changing Corn Using Active/Passive Microwave Remote Sensing

NASA Technical Reports Server (NTRS)

ONeill, P. E.; Joseph, A.; DeLannoy, G.; Lang, R.; Utku, C.; Kim, E.; Houser, P.; Gish, T.

2003-01-01

An extensive field experiment was conducted from May-early October, 2002 at the heavily instrumented USDA-ARS (U.S. Dept. of Agriculture-Agricultural Research Service) OPE3 (Optimizing Production Inputs for Economic and Environmental Enhancement) test site in Beltsville, MD to acquire data needed to address active/passive microwave algorithm, modeling, and ground validation issues for accurate soil moisture retrieval. During the experiment, a tower-mounted 1.4 GHz radiometer (Lrad) and a truck-mounted dual-frequency (1.6 and 4.75 GHz) radar system were deployed on the northern edge of the site. The soil in this portion of the field is a sandy loam (silt 23.5%, sand 60.3%, clay 16.1%) with a measured bulk density of 1.253 g/cu cm. Vegetation cover in the experiment consisted of a corn crop which was measured from just after planting on April 17, 2002 through senescence and harvesting on October 2. Although drought conditions prevailed during the summer, the corn yield was near average, with peak biomass reached in late July.

Acid soil infertility effects on peanut yields and yield components

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

Blamey, F.P.C.

1983-01-01

The interpretation of soil amelioration experiments with peanuts is made difficult by the unpredictibility of the crop and by the many factors altered when ameliorating acid soils. The present study was conducted to investigate the effects of lime and gypsum applications on peanut kernel yield via the three first order yield components, pods per ha, kernels per pod, and kernel mass. On an acid medium sandy loam soil (typic Plinthustult), liming resulted in a highly significant kernel yield increase of 117% whereas gypsum applications were of no significant benefit. As indicated by path coefficient analysis, an increase in the numbermore » of pods per ha was markedly more important in increasing yield than an increase in either the number of kernels per pod or kernel mass. Furthermore, exch. Al was found to be particularly detrimental to pod number. It was postulated that poor peanut yields resulting from acid soil infertility were mainly due to the depressive effect of exch. Al on pod number. Exch. Ca appeared to play a secondary role by ameliorating the adverse effects of exch. Al.« less

Composition and structure of arbuscular-mycorrhizal communities in El Palmar National Park, Argentina.

PubMed

Velázquez, María S; Cabello, Marta N; Barrera, Marcelo

2013-01-01

The arbuscular-mycorrhizal-fungal (AMF) communities from the El Palmar National Park of Entre Ríos Province, Argentina, were investigated and characterized. The species of AMF present in five distinct vegetation types-gallery forest, grassland, marsh, palm forest, and scrubland-were isolated, identified and quantified over 2 y. Forty-six AMF morphotaxa were found. The composition of the AMF communities differed between the seasons, soil and vegetation types. Seasonal variations were observed in members of the Acaulosporaceae, Archaeosporaceae, Claroideoglomeraceae, Gigasporaceae and Pacisporaceae. Depending on soil type, the AMF-spore communities were dominated by members of one of the two main orders of the Glomeromycota. AMF communities from grassland and palm forest, which occur on sandy soils, comprised primarily members of the Diversisporales, with a high percentage of species of Acaulospora and of Gigasporaceae. Communities from the gallery forest, marsh and scrubland, which occur on loam-clay soils, were composed of members of the Glomerales, with a high percentage of spores from species of Glomus. Thus, both AMF and plant communities would appear to be strongly and similarly influenced by edaphic conditions.

Low level off-road vehicle (ORV) traffic negatively impacts macroinvertebrate assemblages at sandy beaches in south-western Australia

NASA Astrophysics Data System (ADS)

Davies, Rebecca; Speldewinde, Peter C.; Stewart, Barbara A.

2016-04-01

Off-road vehicle use is arguably one of the most environmentally damaging human activities undertaken on sandy beaches worldwide. Existing studies focused on areas of high traffic volumes have demonstrated significantly lower abundance, diversity and species richness of fauna in zones where traffic is concentrated. The impact of lower traffic volumes is unknown. This study aimed to investigate the impacts of relatively low-level vehicle traffic on sandy beach fauna by sampling invertebrate communities at eight beaches located in south-western Australia. We found that even low-level vehicle traffic negatively impacts the physical beach environment, and consequently, the ability of many species to survive in this habitat in the face of this disturbance. Compaction, rutting and displacement of the sand matrix were observed over a large area, resulting in significant decreases in species diversity and density, and measurable shifts in community structure on beaches that experienced off-road vehicle traffic. Communities at impact sites did not display seasonal recovery as traffic was not significantly different between seasons. Given a choice between either reducing traffic volumes, or excluding ORV traffic from beaches, our results suggest that the latter would be more appropriate when the retention of ecological integrity is the objective.

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.

Global pattern and controls of soil microbial metabolic quotient

DOE PAGES

Xu, Xiaofeng; Schimel, Joshua P.; Janssens, Ivan A.; ...

2017-05-02

The microbial metabolic quotient (MMQ), microbial respiration per unit of biomass, is a fundamental factor controlling heterotrophic respiration, the largest carbon flux in soils. The magnitude and controls of MMQ at regional scale remain uncertain. We compiled a comprehensive data set of MMQ to investigate the global patterns and controls of MMQ in top 30 cm soils. Published MMQ values, generally measured in laboratory microcosms, were adjusted on ambient soil temperature using long-term (30 yr) average site soil temperature and a Q10 = 2. The area-weighted global average of MMQ_Soil is estimated as 1.8 (1.5–2.2) (95% confidence interval) lmol C•hmore » -1•mmol -1 microbial biomass carbon (MBC) with substantial variations across biomes and between cropland and natural ecosystems. Variation was most closely associated with biological factors, followed by edaphic and meteorological parameters. MMQ_Soil was greatest in sandy clay and sandy clay loam and showed a pH maximum of 6.7 - 0.1 (mean ± se). At large scale, MMQ_Soil varied with latitude and mean annual temperature (MAT), and was negatively correlated with microbial N:P ratio, supporting growth rate theory. These trends led to large differences in MMQ_Soil between natural ecosystems and cropland. When MMQ was adjusted to 11°C (MMQ_Ref), the global MAT in the top 30 cm of soils, the area-weighted global averages of MMQ_Ref was 1.5 (1.3–1.8) lmol C•mmol MBC -1•h -1. The values, trends, and controls of MMQ_Soil add to our understanding of soil microbial influences on soil carbon cycling and could be used to represent microbial activity in global carbon models.« less

Global pattern and controls of soil microbial metabolic quotient

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

Xu, Xiaofeng; Schimel, Joshua P.; Janssens, Ivan A.

The microbial metabolic quotient (MMQ), microbial respiration per unit of biomass, is a fundamental factor controlling heterotrophic respiration, the largest carbon flux in soils. The magnitude and controls of MMQ at regional scale remain uncertain. We compiled a comprehensive data set of MMQ to investigate the global patterns and controls of MMQ in top 30 cm soils. Published MMQ values, generally measured in laboratory microcosms, were adjusted on ambient soil temperature using long-term (30 yr) average site soil temperature and a Q10 = 2. The area-weighted global average of MMQ_Soil is estimated as 1.8 (1.5–2.2) (95% confidence interval) lmol C•hmore » -1•mmol -1 microbial biomass carbon (MBC) with substantial variations across biomes and between cropland and natural ecosystems. Variation was most closely associated with biological factors, followed by edaphic and meteorological parameters. MMQ_Soil was greatest in sandy clay and sandy clay loam and showed a pH maximum of 6.7 - 0.1 (mean ± se). At large scale, MMQ_Soil varied with latitude and mean annual temperature (MAT), and was negatively correlated with microbial N:P ratio, supporting growth rate theory. These trends led to large differences in MMQ_Soil between natural ecosystems and cropland. When MMQ was adjusted to 11°C (MMQ_Ref), the global MAT in the top 30 cm of soils, the area-weighted global averages of MMQ_Ref was 1.5 (1.3–1.8) lmol C•mmol MBC -1•h -1. The values, trends, and controls of MMQ_Soil add to our understanding of soil microbial influences on soil carbon cycling and could be used to represent microbial activity in global carbon models.« less

Bioaccumulation of polycyclic aromatic hydrocarbons and survival of earthworms (Eisenia andrei) exposed to biochar amended soils.

PubMed

Malev, O; Contin, M; Licen, S; Barbieri, P; De Nobili, M

2016-02-01

Biochar has a charcoal polycyclic aromatic structure which allows its long half-life in soil, making it an ideal tool for C sequestration and for adsorption of organic pollutants, but at the same time raises concerns about possible adverse impacts on soil biota. Two biochars were tested under laboratory-controlled conditions on Eisenia andrei earthworms: a biochar produced at low temperature from wine tree cuttings (WTB) and a commercial low tar hardwood lump charcoal (HLB). The avoidance test (48-h exposure) showed that earthworms avoid biochar-treated soil with rates higher than 16 t ha(-1) for HLB and 64 t ha(-1) for WTB. After 42 days, toxic effects on earthworms were observed even at application rates (100 t ha(-1)) that are generally considered beneficial for most crops. The concentration of HLB and WTB required to kill half of earthworms' population (LC50; 95% confidence limits) in the synthetic OECD soil was 338 and 580 t ha(-1), respectively. Accumulation of polycyclic aromatic hydrocarbons (PAH) in earthworms exposed to the two biochar types at 100 t ha(-1) was tested in two soils of different texture. In biochar-treated soils, the average earthworm survival rates were about 64% in the sandy and 78% clay-loam soils. PAH accumulation was larger in the sandy soil and largest in soils amended with HLB. PAH with less than four rings were preferentially scavenged from the soil by biochars, and this behaviour may mask that of the more dangerous components (i.e. four to five rings), which are preferentially accumulated. Earthworms can accumulate PAH as a consequence of exposure to biochar-treated soils and transfer them along the food chain. Soil type and biochar quality are both relevant in determining PAH transfer.

[Trace element supply to ruminants in the German Democratic Republic. 2. Supply of copper].

PubMed

Anke, M; Groppel, B; Lüdke, H; Grün, M; Kleemann, J

1975-06-01

The supply of copper to ruminants as influenced by and depending on the geological origin of soils was investigated in different parts of the GDR by using the hair test. Red clovers (meadow clover and field clover) were used as indicator plants. The following results were obtained: Data on the Cu content of clovers grown on soils of the same geological origin were found to correlate with r = 0,81. After eliminating the effects of Cu antagonists resulting from industrial pollution it was possible to establish numerical relations (B = 0.39 and B = 0.89) between the relative values (specific for the particular location) for the Cu content of the indicator plants and the percentage of cows suffering from Cu deficiencies (6.0 and 5.0 ppm Cu in hair). The lowest percentages of Cu supply to the ruminants (established on the basis of the Cu content of red clovers) were found on diluvial sandy soils, glacial loams and peat and bog soils whereas the highest percentages of Cu were found on weathered soils (of phyllite, gneiss, shell limestone, red marl soils and porphyry). Secondary Cu deficiencies in ruminants may arise, independent of the geological origin of the soil material, in places exposed to the main direction of the winds from major industrial areas (emission of SO2, Cd and Mo). Due to primary and/or secondary deficiencies the supply of Cu to ruminants in various locations (syenite, granite, red sandstone, gneiss, loess; peat soils, diluvial sandy soils) may be insufficient. A detailed description is given of areas where Cu deficiency is likely to occur and recommendations are given on how to use mineral mixtures containing a high proportion of Cu (1.00 g Cu per kg).

Impact of Amendments on the Physical Properties of Soil under Tropical Long-Term No Till Conditions

PubMed Central

Mooney, Sacha J.

2016-01-01

Tropical regions have been considered the world’s primary agricultural frontier; however, some physico-chemical deficiencies, such as low soil organic matter content, poor soil structure, high erodibility, soil acidity, and aluminum toxicity, have affected their productive capacity. Lime and gypsum are commonly used to improve soil chemical fertility, but no information exists about the long-term effects of these products on the physical attributes and C protection mechanisms of highly weathered Oxisols. A field trial was conducted in a sandy clay loam (kaolinitic, thermic Typic Haplorthox) under a no-tillage system for 12 years. The trial consisted of four treatments: a control with no soil amendment application, the application of 2.1 Mg ha-1 phosphogypsum, the application of 2.0 Mg ha-1 lime, and the application of lime + phosphogypsum (2.0 + 2.1 Mg ha-1, respectively). Since the experiment was established in 2002, the rates have been applied three times (2002, 2004, and 2010). Surface liming effectively increased water-stable aggregates > 2.0 mm at a depth of up to 0.2 m; however, the association with phosphogypsum was considered a good strategy to improve the macroaggregate stability in subsoil layers (0.20 to 0.40 m). Consequently, both soil amendments applied together increased the mean weight diameter (MWD) and geometric mean diameter (GMD) in all soil layers, with increases of up to 118 and 89%, respectively, according to the soil layer. The formation and stabilization of larger aggregates contributed to a higher accumulation of total organic carbon (TOC) on these structures. In addition to TOC, the MWD and aggregate stability index were positively correlated with Ca2+ and Mg2+ levels and base saturation. Consequently, the increase observed in the aggregate size class resulted in a better organization of soil particles, increasing the macroporosity and reducing the soil bulk density and penetration resistance. Therefore, adequate soil chemical management plays a fundamental role in improving the soil’s physical attributes in tropical areas under conservative management and highly affected by compaction caused by intensive farming. PMID:27959897

Impact of Amendments on the Physical Properties of Soil under Tropical Long-Term No Till Conditions.

PubMed

Carmeis Filho, Antonio C A; Crusciol, Carlos A C; Guimarães, Tiara M; Calonego, Juliano C; Mooney, Sacha J

2016-01-01

Tropical regions have been considered the world's primary agricultural frontier; however, some physico-chemical deficiencies, such as low soil organic matter content, poor soil structure, high erodibility, soil acidity, and aluminum toxicity, have affected their productive capacity. Lime and gypsum are commonly used to improve soil chemical fertility, but no information exists about the long-term effects of these products on the physical attributes and C protection mechanisms of highly weathered Oxisols. A field trial was conducted in a sandy clay loam (kaolinitic, thermic Typic Haplorthox) under a no-tillage system for 12 years. The trial consisted of four treatments: a control with no soil amendment application, the application of 2.1 Mg ha-1 phosphogypsum, the application of 2.0 Mg ha-1 lime, and the application of lime + phosphogypsum (2.0 + 2.1 Mg ha-1, respectively). Since the experiment was established in 2002, the rates have been applied three times (2002, 2004, and 2010). Surface liming effectively increased water-stable aggregates > 2.0 mm at a depth of up to 0.2 m; however, the association with phosphogypsum was considered a good strategy to improve the macroaggregate stability in subsoil layers (0.20 to 0.40 m). Consequently, both soil amendments applied together increased the mean weight diameter (MWD) and geometric mean diameter (GMD) in all soil layers, with increases of up to 118 and 89%, respectively, according to the soil layer. The formation and stabilization of larger aggregates contributed to a higher accumulation of total organic carbon (TOC) on these structures. In addition to TOC, the MWD and aggregate stability index were positively correlated with Ca2+ and Mg2+ levels and base saturation. Consequently, the increase observed in the aggregate size class resulted in a better organization of soil particles, increasing the macroporosity and reducing the soil bulk density and penetration resistance. Therefore, adequate soil chemical management plays a fundamental role in improving the soil's physical attributes in tropical areas under conservative management and highly affected by compaction caused by intensive farming.

Occasional large emissions of nitrous oxide and methane observed in stormwater biofiltration systems.

PubMed

Grover, Samantha P P; Cohan, Amanda; Chan, Hon Sen; Livesley, Stephen J; Beringer, Jason; Daly, Edoardo

2013-11-01

Designed, green infrastructures are becoming a customary feature of the urban landscape. Sustainable technologies for stormwater management, and biofilters in particular, are increasingly used to reduce stormwater runoff volumes and peaks as well as improve the water quality of runoff discharged into urban water bodies. Although a lot of research has been devoted to these technologies, their effect in terms of greenhouse gas fluxes in urban areas has not been yet investigated. We present the first study aimed at quantifying greenhouse gas fluxes between the soil of stormwater biofilters and the atmosphere. N2O, CH4, and CO2 were measured periodically over a year in two operational vegetated biofiltration cells at Monash University in Melbourne, Australia. One cell had a saturated zone at the bottom, and compost and hardwood mulch added to the sandy loam filter media. The other cell had no saturated zone and was composed of sandy loam. Similar sedges were planted in both cells. The biofilter soil was a small N2O source and a sink for CH4 for most measurement events, with occasional large emissions of both N2O and CH4 under very wet conditions. Average N2O fluxes from the cell with the saturated zone were almost five-fold greater (65.6 μg N2O-N m(-2) h(-1)) than from the other cell (13.7 μg N2O-N m(-2) h(-1)), with peaks up to 1100 μg N2O-N m(-2) h(-1). These N2O fluxes are of similar magnitude to those measured in other urban soils, but with larger peak emissions. The CH4 sink strength of the cell with the saturated zone (-3.8 μg CH4-C m(-2) h(-1)) was lower than the other cell (-18.3 μg CH4-C m(-2) h(-1)). Both cells of the biofilter appeared to take up CH4 at similar rates to other urban lawn systems; however, the biofilter cells displayed occasional large CH4 emissions following inflow events, which were not seen in other urban systems. CO2 fluxes increased with soil temperature in both cells, and in the cell without the saturated zone CO2 fluxes decreased as soil moisture increased. Other studies of CO2 fluxes from urban soils have found both similar and larger CO2 emissions than those measured in the biofilter. The results of this study suggest that the greenhouse gas footprint of stormwater treatment warrant consideration in the planning and implementation of engineered green infrastructures. Copyright © 2013 Elsevier B.V. All rights reserved.

Marginal cost curves for water footprint reduction in irrigated agriculture: guiding a cost-effective reduction of crop water consumption to a permit or benchmark level

NASA Astrophysics Data System (ADS)

Chukalla, Abebe D.; Krol, Maarten S.; Hoekstra, Arjen Y.

2017-07-01

Reducing the water footprint (WF) of the process of growing irrigated crops is an indispensable element in water management, particularly in water-scarce areas. To achieve this, information on marginal cost curves (MCCs) that rank management packages according to their cost-effectiveness to reduce the WF need to support the decision making. MCCs enable the estimation of the cost associated with a certain WF reduction target, e.g. towards a given WF permit (expressed in m3  ha-1 per season) or to a certain WF benchmark (expressed in m3  t-1 of crop). This paper aims to develop MCCs for WF reduction for a range of selected cases. AquaCrop, a soil-water-balance and crop-growth model, is used to estimate the effect of different management packages on evapotranspiration and crop yield and thus the WF of crop production. A management package is defined as a specific combination of management practices: irrigation technique (furrow, sprinkler, drip or subsurface drip); irrigation strategy (full or deficit irrigation); and mulching practice (no, organic or synthetic mulching). The annual average cost for each management package is estimated as the annualized capital cost plus the annual costs of maintenance and operations (i.e. costs of water, energy and labour). Different cases are considered, including three crops (maize, tomato and potato); four types of environment (humid in UK, sub-humid in Italy, semi-arid in Spain and arid in Israel); three hydrologic years (wet, normal and dry years) and three soil types (loam, silty clay loam and sandy loam). For each crop, alternative WF reduction pathways were developed, after which the most cost-effective pathway was selected to develop the MCC for WF reduction. When aiming at WF reduction one can best improve the irrigation strategy first, next the mulching practice and finally the irrigation technique. Moving from a full to deficit irrigation strategy is found to be a no-regret measure: it reduces the WF by reducing water consumption at negligible yield reduction while reducing the cost for irrigation water and the associated costs for energy and labour. Next, moving from no to organic mulching has a high cost-effectiveness, reducing the WF significantly at low cost. Finally, changing from sprinkler or furrow to drip or subsurface drip irrigation reduces the WF, but at a significant cost.

The effect of mulching and soil compaction on fungi composition and microbial communities in the rhizosphere of soybean

NASA Astrophysics Data System (ADS)

Frac, M.; Siczek, A.; Lipiec, J.

2009-04-01

The soil environment is the habitat of pathogenic and saprotrophic microorganisms. The composition of the microbial community are related to biotic and abiotic factors, such as root exudates, crop residues, climate factors, mulching, mineral fertilization, pesticides introduction and soil compaction. The aim of the study was to determine the effect of the mulching and soil compaction on the microorganism communities in the rhizosphere soil of soybean. The studies were carried out on silty loam soil (Orthic Luvisol) developed from loess (Lublin, Poland). The experiment area was 192m2 divided into 3 sections consisted of 6 micro-plots (7m2). Three levels of soil compaction low, medium and heavy obtained through tractor passes were compared. The soil was compacted and loosened within seedbed layer 2 weeks before sowing. Soybean "Aldana" seeds were inoculated with Bradyrhizobium japonicum and were sown with interrow spacing of 0.3m. Wheat straw (as mulch) was uniformly spread on the half of each micro-plot at an amount of 0.5kg m-1 after sowing. Rhizosphere was collected three times during growing season of soybean. Microbiological analyses were conducted in 3 replications and included the determination of: the total number of bacteria and fungi, the number of bacteria Pseudomonas sp. and Bacillus sp., the genus identification of fungi isolated from rhizosphere of soybean. Results indicated a positive effect of mulching on the increase number of all groups of examined rhizosphere microorganisms (fungi, bacteria, Pseudomonas sp., Bacillus sp.). The highest number of the microorganisms was found in the low and medium compacted soil and markedly decreased in the most compacted soil. Relatively high number of antagonistic fungi (Penicillium sp., Trichoderma sp.) was recorded in the rhizosphere of low and medium compacted soil, particularly in mulched plots. The presence of these fungi can testify to considerable biological activity, which contributes to the improvement of the phytosanitary condition of the soil. However, the decrease of the antagonistic microorganism number in the heavy compacted soil can be responsible for appearance higher number of the potentially phytopathogenic fungi (Fusarium sp., Phoma sp.). Further research, with using molecular technique, will help better understanding interactions between plant and microorganisms in the soybean rhizosphere under different soil management conditions.

Changes in Soil Carbon Turnover after Five Years of Bioenergy Cropping Systems from a Long-Term Incubation Experiment and Radiocarbon Measurements.

NASA Astrophysics Data System (ADS)

Szymanski, L. M.; Sanford, G. R.; Heckman, K. A.; Jackson, R. D.; Marin-Spiotta, E.

2016-12-01

In the face of climate change, the global production of bioenergy crops has increased in response to policies calling for non-fossil energy sources as a means to mitigate rising atmospheric carbon (C) concentrations. To provide overall C sequestration benefits, identifying biomass crops that can maintain or enhance soil resources is desirable for sustainable bioenergy production. The objective of our study was to compare the effects of four bioenergy cropping systems on SOM dynamics in two agricultural soils: Mollisols at the University of Wisconsin Agricultural Research Station in Arlington, Wisconsin and Alfisols at Kellogg Biological Station in Hickory Corners, Michigan, USA. We used fresh soils collected in 2013 and archived soils collected in 2008 to measure differences among biofuel crops after 5 years of management. Using a 365-day laboratory soil incubation and radiocarbon measurements of bulk soil and respired C, we separated soils into three SOM pools and determined their corresponding turnover times. Total soil C respired from surface soils increased in the order: mixed species perennials > monoculture perennials > monoculture annuals. More C was associated with the active fraction in the sandy loam Alfisol and with the slow-cycling fraction in the silt loam Mollisol. Radiocarbon content of respired CO2 did not differ between corn and switchgrass, but did differ between 2008 and 2013. The respiration of more radiocarbon-depleted C after 5 years of cultivation may be due to an initial flux of young C following tillage in 2008 or to depletion of labile plant inputs with continued harvest. All bioenergy cropping systems lost soil C after 5 years. Monoculture perennial switchgrass systems did not provide significant C sequestration benefits, as expected, compared to monoculture annual corn systems. Bioenergy crop land-use change affects soil C dynamics, with implications for assessing C costs associated with biofuel production.

Change in soluble phosphorus in soils following fertilization is dependent on initial Mehlich-3 phosphorus.

PubMed

Bond, C Ryan; Maguire, R O; Havlin, J L

2006-01-01

There is a lack of information on how fertilization and initial Mehlich-3 phosphorus (M3P) interact to affect water soluble P (WSP) in soils. Our objectives were to (i) quantify the relationship between WSP and M3P for four textural diverse benchmark soils of North Carolina (NC) and (ii) quantify the change in WSP concentrations following P additions to soils over a wide range of initial M3P. Soils known to represent a wide range in M3P were collected from an Autryville loamy sand (loamy, siliceous, subactive, thermic Arenic Paleudults), Wasda muck (fine-loamy, mixed, semiactive, acid, thermic Histic Humaquepts), Georgeville silt loam (fine, kaolinitic, thermic Typic Kanhapludults), and Pacolet sandy clay loam (fine, kaolinitic, thermic Typic Kanhapludults) and analyzed for M3P, Fe, Al, and WSP. An incubation study was also conducted where four samples representing a range in M3P from each series were fertilized at rates of 150 and 300 kg P ha(-1), and WSP was measured at 1, 7, and 21 d after fertilization. The Wasda muck exhibited a change point at 115 mg P kg(-1) across a broad range of M3P concentrations (60-238 mg kg(-1)) while Autryville, Georgeville, and Pacolet series (with ranges in M3P of 32-328, 119-524, 0-1034 mg P kg(-1), respectively) maintained linear relationships between WSP and M3P. For the fertilized soils, significant increases in WSP occurred regardless of P rate. Yet, WSP concentrations were greater in soils with greater initial M3P. Thus, these data suggest that shifting animal waste applications to fields of relatively lower M3P concentrations would have an immediate impact on reducing risk for P losses, if all other factors are equal.

Assessment of Cu applications in two contrasting soils-effects on soil microbial activity and the fungal community structure.

PubMed

Keiblinger, Katharina M; Schneider, Martin; Gorfer, Markus; Paumann, Melanie; Deltedesco, Evi; Berger, Harald; Jöchlinger, Lisa; Mentler, Axel; Zechmeister-Boltenstern, Sophie; Soja, Gerhard; Zehetner, Franz

2018-03-01

Copper (Cu)-based fungicides have been used in viticulture to prevent downy mildew since the end of the 19th century, and are still used today to reduce fungal diseases. Consequently, Cu has built up in many vineyard soils, and it is still unclear how this affects soil functioning. The present study aimed to assess the short and medium-term effects of Cu contamination on the soil fungal community. Two contrasting agricultural soils, an acidic sandy loam and an alkaline silt loam, were used for an eco-toxicological greenhouse pot experiment. The soils were spiked with a Cu-based fungicide in seven concentrations (0-5000 mg Cu kg -1 soil) and alfalfa was grown in the pots for 3 months. Sampling was conducted at the beginning and at the end of the study period to test Cu toxicity effects on total microbial biomass, basal respiration and enzyme activities. Fungal abundance was analysed by ergosterol at both samplings, and for the second sampling, fungal community structure was evaluated via ITS amplicon sequences. Soil microbial biomass C as well as microbial respiration rate decreased with increasing Cu concentrations, with EC 50 ranging from 76 to 187 mg EDTA-extractable Cu kg -1 soil. Oxidative enzymes showed a trend of increasing activity at the first sampling, but a decline in peroxidase activity was observed for the second sampling. We found remarkable Cu-induced changes in fungal community abundance (EC 50 ranging from 9.2 to 94 mg EDTA-extractable Cu kg -1 soil) and composition, but not in diversity. A large number of diverse fungi were able to thrive under elevated Cu concentrations, though within the order of Hypocreales several species declined. A remarkable Cu-induced change in the community composition was found, which depended on the soil properties and, hence, on Cu availability.

Invasion Potential of Two Tropical Physalis Species in Arid and Semi-Arid Climates: Effect of Water-Salinity Stress and Soil Types on Growth and Fecundity.

PubMed

Ozaslan, Cumali; Farooq, Shahid; Onen, Huseyin; Bukun, Bekir; Ozcan, Selcuk; Gunal, Hikmet

2016-01-01

Invasive plants are recognized for their impressive abilities to withstand adverse environmental conditions however, all invaders do not express the similar abilities. Therefore, survival, growth, nutrient uptake and fecundity of two co-occurring, invasive Physalis species were tested under water and salinity stresses, and different soil textures in the current study. Five different water stress levels (100, 75, 50, 25, and 12.5% pot water contents), four different soil salinity levels (0, 3, 6, and 12 dSm-1) and four different soil textures (67% clay, 50% clay, silt clay loam and sandy loam) were included in three different pot experiments. Both weeds survived under all levels of water stress except 12.5% water contents and on all soil types however, behaved differently under increasing salinity. The weeds responded similarly to salinity up till 3 dSm-1 whereas, P. philadelphica survived for longer time than P. angulata under remaining salinity regimes. Water and salinity stress hampered the growth and fecundity of both weeds while, soil textures had slight effect. Both weeds preferred clay textured soils for better growth and nutrient uptake however, interactive effect of weeds and soil textures was non-significant. P. angulata accumulated higher K and Na while P. philadelphica accrued more Ca and Mg as well as maintained better K/Na ratio. P. angulata accumulated more Na and P under salinity stress while, P. philadelphica accrued higher K and Mg, and maintained higher K/Na ratio. Collectively, highest nutrient accumulation was observed under stress free conditions and on clay textured soils. P. philadelphica exhibited higher reproductive output under all experimental conditions than P. angulata. It is predicted that P. philadelphica will be more problematic under optimal water supply and high salinity while P. angulata can better adapt water limited environments. The results indicate that both weeds have considerable potential to further expand their ranges in semi-arid regions of Turkey.

Geochemical Assessment of Groundwater in the Peri-urban Environment of Buenos Aires, Argentina

NASA Astrophysics Data System (ADS)

Gallardo, A.

2014-12-01

Groundwater pollution is a major concern in peri-urban environments. Thus, water quality is being investigated at several domestic wells in Brandsen, 70 km south of Buenos Aires, Argentina. To present, about 20 water sources were sampled in orchards and small farms of the area. There is limited data about the wells construction, although collected information suggests that groundwater is derived from the superficial sandy loams of the Pampean Aquifer. Samples were analysed for major inorganic elements using ion chromatography and ICP-MS. Titration was used to estimate alkalinity. Physical characteristics (EC, pH, temperature) were measured on site. Results show that groundwater pH ranges from 6.5 to 7.8, with a specific conductance of 180 to 255 mS/m. A peak of 360 mS/m in one horticultural parcel is associated to local NO3- concentrations up to 140 mg/L. This value exceeds the maximum recommendations set by the WHO (50 mg/L). Considering that fertilizer inputs in that property are negligible, the high levels of NO3- might be attributed to effluents from a neighbour septic tank. An increase in NO3- (>150mg/L) was also detected in two conventional farms. This increase correlates to elevated SO42- concentrations (>300 mg/L) suggesting thus, fertilizers percolation into the saturated zone. The leaching of these fluids might be exacerbated by irrigation during new planting, and accumulations of fertilizer-solids in the root zones from previous seasons. Chloride concentrations average ~90 mg/L and would not pose a threat to health at the moment. Its main origin would be related to connate waters in the loam matrix, although some anthropogenic inputs might occur in the previously described farms. In general, the rest of the analysed elements fall within acceptable levels for drinking purposes as well. Nevertheless, further work is still necessary to better define the fate of the potential harmful elements and assess seasonal variations in water quality.

Invasion Potential of Two Tropical Physalis Species in Arid and Semi-Arid Climates: Effect of Water-Salinity Stress and Soil Types on Growth and Fecundity

PubMed Central

Ozaslan, Cumali; Bukun, Bekir; Ozcan, Selcuk

2016-01-01

Invasive plants are recognized for their impressive abilities to withstand adverse environmental conditions however, all invaders do not express the similar abilities. Therefore, survival, growth, nutrient uptake and fecundity of two co-occurring, invasive Physalis species were tested under water and salinity stresses, and different soil textures in the current study. Five different water stress levels (100, 75, 50, 25, and 12.5% pot water contents), four different soil salinity levels (0, 3, 6, and 12 dSm-1) and four different soil textures (67% clay, 50% clay, silt clay loam and sandy loam) were included in three different pot experiments. Both weeds survived under all levels of water stress except 12.5% water contents and on all soil types however, behaved differently under increasing salinity. The weeds responded similarly to salinity up till 3 dSm-1 whereas, P. philadelphica survived for longer time than P. angulata under remaining salinity regimes. Water and salinity stress hampered the growth and fecundity of both weeds while, soil textures had slight effect. Both weeds preferred clay textured soils for better growth and nutrient uptake however, interactive effect of weeds and soil textures was non-significant. P. angulata accumulated higher K and Na while P. philadelphica accrued more Ca and Mg as well as maintained better K/Na ratio. P. angulata accumulated more Na and P under salinity stress while, P. philadelphica accrued higher K and Mg, and maintained higher K/Na ratio. Collectively, highest nutrient accumulation was observed under stress free conditions and on clay textured soils. P. philadelphica exhibited higher reproductive output under all experimental conditions than P. angulata. It is predicted that P. philadelphica will be more problematic under optimal water supply and high salinity while P. angulata can better adapt water limited environments. The results indicate that both weeds have considerable potential to further expand their ranges in semi-arid regions of Turkey. PMID:27741269

Mid-term effect of silvicultural treatments on carbon cycling in a Mediterranean Pinus halepensis forest

NASA Astrophysics Data System (ADS)

Lull, Cristina; Bautista, Inmaculada; Lado-Monserrat, Luis; Lidón, Antonio

2014-05-01

Twelve years after a silvicultural treatment in a Pinus halepensis forest, seasonal variation of carbon pools were compared between three treatments: a control reference with no treatment (T0); a moderate thinning with 40% of mean basal area removed (T40); a total clearcut (T100). The silvicultural treatments were performed following a randomized block design. The three blocks selected, namely called Tuéjar izquierda (TI), Tuéjar derecha (TD) and Chelv a(CH) are located in Valencia (East of Spain) and have the same canopy characteristics, but different soils. Soil environmental conditions in each plot were continuously recorded with a pluviometer and two soil moisture and temperature sensors installed at 5 and 10 cm depth connected to a data logger. During two years (2009 and 2010), superficial soil samples (0-15 cm) were collected thrice per year, in spring, summer and autumn. In each sample, water holding capacity, total organic carbon (TOC), soluble organic carbon (SOC), microbial biomass carbon (MBC) and soil respiration were determined. Our results showed that the textural composition (clay loam for TI and TD soils and sandy loam for CH soil), affected carbon pools. Total organic carbon differs significantly between blocks, and also between T40 and the other two treatments in Chelva. Seasonal analysis of the data could not be performed because summer in the year 2009 was very dry compared with 2010. The SOC and MBC pools are related with TOC which explain 51% of the temporal and spatial variation of the SOC and 38% of the MBC. TOC also explain 75% of soil respiration variance. Despite the differences in soil properties between blocks, the silvicultural treatment affect significantly to the BMC pool and the basal respiration flux. Moreover, the most labile pool of soil organic carbon is affected by environmental variables such as soil temperature and for this reason changes seasonally.

Exploring the use of weathering indexes in an alluvial fan chronology

NASA Astrophysics Data System (ADS)

Hardenbicker, Ulrike; Watanabe, Makiko; Kotowich, Roberta

2015-04-01

Alluvial fan sediments can act as an archive of local environmental history. Two borehole cores (FN 350 cm and AG 850cm) from Holocene alluvial fans located in the Qu'Appelle Valley in southern Saskatchewan were analyzed in order to identify how changes in land use of upland catchment plateaus modified the pattern and rate of sediment delivery to the fan. Due to the lack of material for radiometric dating a chronology of depositional events within the alluvial fans was established by using lithostratigraphy data of soils and sediments. In order to establish a more detailed relative chronology we evaluated if weathering indexes (the Parker Index, the CaO/ZrO2 molar ratio, the Product Index) originally developed for studies of in situ weathering of bedrock, are suitable to assess sediment weathering within alluvial fan sediments. To quantify the degree of weathering within the sediment samples the three indexes of weathering were calculated using the proportions of elements measure by Energy Dispersive X-ray Spectroscopy and there is an inverse relationship between weathering index and sample age. For further statistical analyses the fan sediments were classified into three groups: a sheet flow facies of well sorted silt loam and sandy loam textures, bed load facies characterized by high sand and gravel content and layers with high organic matter in combination with higher clay content indicative of in situ weathering and soil development. First results show that the Product Index may be the most suitable weathering index to indicate weathering or input of less weathered sediment within the sheet flow and bed load facies. In general, the weathering indexes do not take into account complexities of the weathering processes nor the overall environmental conditions in an alluvial fan. But chemical weathering indexes accompanied by geophysical and geo-chemical information have value, especially when the amount of sample material is limited.

Winery vermicomposts to control the leaching of diuron, imidacloprid and their metabolites: role of dissolved organic carbon content.

PubMed

Fernández-Bayo, Jesús D; Nogales, Rogelio; Romero, Esperanza

2015-01-01

Soil organic amendment addition is an effective practice in Mediterranean areas due to its associated high agricultural benefits and its potential to reduce the pesticide impact on water resources. However, their metabolites have received scarce attention, even when they may pose more risk than their parent compounds. Two winery vermicomposts obtained from spent grape marc (V1) and the mixture vine shoot-biosolid vinasses (V2) have been investigated as low cost organic amendments to minimize the leaching of diuron, imidacloprid and their metabolites in columns packed with a sandy loam (S1) and a silty-clay loam soil (S2) under steady state flow conditions. In the unamended soil columns, leached amounts of diuron were 75% and 53% in S1 and S2, respectively. Its metabolites (3-(3,4-dichlorophenyl)-1-methylurea, DPMU; and 3,4-dichlorophenylurea, DPU) percolated less than 35% of the total applied amount. The amount of the metabolite 3,4-dichloroaniline (DCA) was 2% and 30% for S1 and S2, respectively. Leaching of imidacloprid was 79% and 96% for S1 and S2, respectively, while its metabolite 6-chloronicotinic acid (CNA) was entirely leached. In the vermicompost-amended columns, the leaching of diuron was reduced 2 to 3-fold. DPMU and DPU were also significantly reduced (more than 6-fold). DCA did not appear in any of the leachates of the amended soil columns. Imidacloprid leaching was reduced 1 to 2-folds in the amended columns. The amendments did not affect the transport of CNA. The dissolved organic carbon (DOC) from the vermicomposts did not enhance pesticide transport throughout the soil in any case. This qualitative study presents these vermicomposts as an effective potential low-cost tool in reducing pesticide and metabolite leaching. The next step would be to test them under more realistic conditions.

Stimulation of N2 O emission by manure application to agricultural soils may largely offset carbon benefits: a global meta-analysis.

PubMed

Zhou, Minghua; Zhu, Bo; Wang, Shijie; Zhu, Xinyu; Vereecken, Harry; Brüggemann, Nicolas

2017-10-01

Animal manure application as organic fertilizer does not only sustain agricultural productivity and increase soil organic carbon (SOC) stocks, but also affects soil nitrogen cycling and nitrous oxide (N 2 O) emissions. However, given that the sign and magnitude of manure effects on soil N 2 O emissions is uncertain, the net climatic impact of manure application in arable land is unknown. Here, we performed a global meta-analysis using field experimental data published in peer-reviewed journals prior to December 2015. In this meta-analysis, we quantified the responses of N 2 O emissions to manure application relative to synthetic N fertilizer application from individual studies and analyzed manure characteristics, experimental duration, climate, and soil properties as explanatory factors. Manure application significantly increased N 2 O emissions by an average 32.7% (95% confidence interval: 5.1-58.2%) compared to application of synthetic N fertilizer alone. The significant stimulation of N 2 O emissions occurred following cattle and poultry manure applications, subsurface manure application, and raw manure application. Furthermore, the significant stimulatory effects on N 2 O emissions were also observed for warm temperate climate, acid soils (pH < 6.5), and soil texture classes of sandy loam and clay loam. Average direct N 2 O emission factors (EFs) of 1.87% and 0.24% were estimated for upland soils and rice paddy soils receiving manure application, respectively. Although manure application increased SOC stocks, our study suggested that the benefit of increasing SOC stocks as GHG sinks could be largely offset by stimulation of soil N 2 O emissions and aggravated by CH 4 emissions if, particularly for rice paddy soils, the stimulation of CH 4 emissions by manure application was taken into account. © 2017 John Wiley & Sons Ltd.

Microbial Ecology of Soil Aggregation in Agroecosystems

NASA Astrophysics Data System (ADS)

Hofmockel, K. S.; Bell, S.; Tfailly, M.; Thompson, A.; Callister, S.

2017-12-01

Crop selection and soil texture influence the physicochemical attributes of the soil, which structures microbial communities and influences soil C cycling storage. At the molecular scale, microbial metabolites and necromass alter the soil environment, which creates feedbacks that influence ecosystem functions, including soil C accumulation. By integrating lab to field studies we aim to identify the molecules, organisms and metabolic pathways that control carbon cycling and stabilization in bioenergy soils. We investigated the relative influence of plants, microbes, and minerals on soil aggregate ecology at the Great Lakes Bioenergy Research experiment. Sites in WI and MI, USA have been in corn and switchgrass cropping systems for a decade. By comparing soil aggregate ecology across sites and cropping systems we are able to test the relative importance of plant, microbe, mineral influences on soil aggregate dynamics. Soil microbial communities (16S) differ in diversity and phylogeny among sites and cropping systems. FT-ICR MS revealed differences in the molecular composition of water-soluble fraction of soil organic matter for cropping systems and soil origin for both relative abundance of assigned formulas and biogeochemical classes of compounds. We found the degree of aggregation, measured by mean weighted diameter of aggregate fractions, is influenced by plant-soil interactions. Similarly, the proportion of soil aggregate fractions varied by both soil and plant factors. Differences in aggregation were reflected in differences in bacterial, but not fungal community composition across aggregate fractions, within each soil. Scanning electron microscopy revealed stark differences in mineral-organic interactions that influence the microbial niche and the accessibility of substrates within the soil. The clay soils show greater surface heterogeneity, enabling interactions with organic fraction of the soil. This is consistent with molecular data that reveal differences in the abundance of chemical classes in clay loams compared to sandy loams. Together our data demonstrate that the potential for aggregation and C storage is strongly influenced by soil mineralogy with important implications for plant-microbe interactions that mediate C biogeochemistry.

Reconstructing Mississippi River Deltaic Wetland Hydrostratigraphy Using Compositional Kriging Method - Implications for Groundwater, Groundwater-River Water Interaction, Subsidence and Deltaic Wetland Evolution

NASA Astrophysics Data System (ADS)

Li, A.; Tsai, F. T. C.; White, C.; Wang, J.; Bentley, S. J.; Xu, K.

2016-12-01

River deltaic wetlands are formed along coastal area where sediment-laden river water reaches ocean. A river deltaic wetland is a complex system that mainly consists of groundwater, soil and vegetation components. Groundwater makes up a large portion of the system. The wetlands are important to human being and wild life. This research focuses on hydrostratigraphic architecture of the Mississippi River deltaic wetland. Research area includes lower Barataria Bay and lower Breton Sound that located on the Mississippi River Delta in southern Louisiana. In this study, a three dimensional hydrostratigraphy model is constructed using coring survey grain size data and geostatistics approach. A three-dimensional grid system is firstly constructed to cover the whole research domain. Each cell of the grid has a dimension of 100 meters by 100 meters by 1 centimeter (length by width by depth). Then Compositional Kriging and Gaussian Sequential Simulation methods are adopted to estimate soil composition (sand, silt and clay fractions) for each cell. A result has been generated to reveal spatial hydro facies variation by cutting cross sections and extracting soil texture maps at different locations. In the result, bay silt makes a large portion of the sediments body and sandy sediments are shown at different depths in both sides of the river. In Barataria Bay, sand bodies are lenticular, relatively thick and vertical continuous, however, in Breton Sound, sand bodies are sheet-like, relatively thin and vertical non-continuous. It is likely that the sandy sediments in Barataria Bay and Breton Sound are deposited in distal distributary and overbank flow respectively. Larger sandy bodies are prone to form in the distal distributary than in the overbank flow. Sandy units formed in the distal distributary can provide better interconnection between river water and groundwater than that formed in the overbank flow. Larger sandy bodies also provides more space to store groundwater. More silty and clayey sediments in the Breton Sound side make it more subject to compactional subsidence. More sandy sediments occur at the shallow portion of the Breton Sound than Barataria Bay. And these sands are interpreted as transgressive product that is formed by reworking forces such as wind, tide, cold front and storm.

Agricultural landscapes dynamic at the North-West of Russia

NASA Astrophysics Data System (ADS)

Guzel, N.

2012-04-01

The process of reduction of agrolandscapes has taken place some decades in the North-Western European Russia. During 100 last years the area of agricultural lands have reduced in 1,4 times on the Karelian Isthmus. The most part of it had been abandoned after change of State border after of the Second World War. The processes of overgrowing of the former agricultural lands are studied on the landscapes base. The types of landscapes are distinguished on the based of the morphological relief symptoms, characteristics of the structure rock and the humid regime. Agricultural lands occupy landscapes such as kames, sandy, sandy-loam, clayey plains, sometimes with excess moistening, sandy fluvioglacial plains, loamy morainic plains, mesotrophic and evtrophic peat-bogs. Four stages can be revealed. I - (period to 20 years after termination of agricultural use) - grass-herb meadow with unclosed brush II - (20 - 40) - shrub layer with closed or low-closed canopy and unclosed or low closed small-leaved regrowth III - (40 - 80) - closed small-leaved forest, sometime including the coniferous trees IY - predomination of the coniferous on small-leaved trees Reestablish vegetation successions can be realised by different ways, with different rate, including various trees and ecological groups of species in different landscapes. In the different sites many traits in common are discovered during this processes. The processes taking place in soil of abandoned agricultural lands are expressed more poorly than in vegetation as soil is more "conservative" element of landscape. Now most area occupies former agricultural lands, inhering on III stage and presenting itself small-leaved forest. Over the last decade because of a change in the socio-political situation there has emerged a tendency towards an increase in the area of the cultivated land in the Karelian Isthmus including the secondary development of previously abandoned lands. However, this process is going on spontaneously; there are quite a few cases of the use of woodland valuable in recreational and forestry respects for dacha or country-cottage construction. From fast change the pattern of ownership on ground is necessary urgent inventory of being available ground resources, including with the purposes of creation of new especially protected territories. It is important to emphasise, that to guards should be subject not only sites so-called quot.; untouched quot.; a nature, but also area with different overgrowth succession stages agricultural lands, where biodiversity raises.

Evaluation of six pesticides leaching indexes using field data of herbicide application in Casablanca Valley, Chile.

PubMed

Kogan, M; Rojas, S; Gómez, P; Suárez, F; Muñoz, J F; Alister, C

2007-01-01

A field study was performed to evaluate the accuracy of six pesticide screening leaching indexes for herbicide movement. Adsorption, dissipation and soil movement were studied in a vineyard in a sandy loam soil during 2005 season. Simazine, diuron, pendimethalin, oxyfluorfen and flumioxazin were applied to bare soil at rates commonly used, and their soil concentrations throughout soil profile were determined at 0, 10, 20, 40 and 90 days after application (DAA). Herbicides were subjected to two pluviometric regimens, natural field condition and modified conditions (plus natural rainfall 180 mm). Leaching indexes utilized were: Briggs's Rf, Hamaker's Rf, LEACH, LPI, GUS and LIX. Simazine reached 120 cm, diuron 90 cm, flumioxazin 30 cm soil depth respectively. Pendimethalin and oxyfluorfen were retained up to 5 cm. None of the herbicides leaching was affected by rainfall regimen. Only flumioxazin field dissipation was clearly affected by pluviometric condition. The best representation of the herbicide soil depth movement and leaching below 15 cm soil depth were: Hamaker's Rf < Briggs's Rf < GUS < LPI, < LEACH < LIX. Field results showed a good correlation between herbicides K(d) and their soil depth movement and mass leached below 15 cm soil depth.

Field dissipation of oxyfluorfen in onion and its dynamics in soil under Indian tropical conditions.

PubMed

Janaki, P; Sathya Priya, R; Chinnusamy, C

2013-01-01

Oxyfluorfen, a diphenyl-ether herbicide is being used to control annual and perennial broad-leaved weeds and sedges in a variety of field crops including onion. The present study was aimed to investigate the dynamics and field persistence of oxyfluorfen in onion plant, bulb and soil under Indian tropical conditions. Application of four rates of oxyfluorfen viz., 200, 250, 300 and 400 g AI ha(-1) as pre-emergence gave good weed control in field experiment with onion. The oxyfluorfen residue dissipated faster in plant than in soil respectively, with a mean half-life of 6.1 and 11.2 days. Dissipation followed first-order kinetics. In laboratory column leaching experiments, 17 percent of the applied oxyfluorfen was recovered from the soil and indicates its solubility in water and mobility in sandy clay loam soil was low. A sorption study revealed that the adsorption of oxyfluorfen to the soil was highly influenced by the soil organic carbon with the Koc value of 5450. The study concludes that the dissipation of oxyfluorfen in soil and onion was dependent on the physico-chemical properties of the soil and environmental conditions.

Effects of hydrated lime and quicklime on the decay of buried human remains using pig cadavers as human body analogues.

PubMed

Schotsmans, Eline M J; Denton, John; Dekeirsschieter, Jessica; Ivaneanu, Tatiana; Leentjes, Sarah; Janaway, Rob C; Wilson, Andrew S

2012-04-10

Recent casework in Belgium involving the search for human remains buried with lime, demonstrated the need for more detailed understanding of the effect of different types of lime on cadaver decomposition and its micro-environment. Six pigs (Sus scrofa) were used as body analogues in field experiments. They were buried without lime, with hydrated lime (Ca(OH)(2)) and with quicklime (CaO) in shallow graves in sandy loam soil in Belgium and recovered after 6 months of burial. Observations from these field recoveries informed additional laboratory experiments that were undertaken at the University of Bradford, UK. The combined results of these studies demonstrate that despite conflicting evidence in the literature, hydrated lime and quicklime both delay the decay of the carcass during the first 6 months. This study has implications for the investigation of clandestine burials and for a better understanding of archaeological plaster burials. Knowledge of the effects of lime on decomposition processes also has bearing on practices involving burial of animal carcasses and potentially the management of mass graves and mass disasters by humanitarian organisations and DVI teams. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Mini rainfall simulation for assessing soil erodibility

NASA Astrophysics Data System (ADS)

Peters, Piet; Palese, Dina; Baartman, Jantiene

2016-04-01

The mini rainfall simulator is a small portable rainfall simulator to determine erosion and water infiltration characteristics of soils. The advantages of the mini rainfall simulator are that it is suitable for soil conservation surveys and light and easy to handle in the field. Practical experience over the last decade has shown that the used 'standard' shower is a reliable method to assess differences in erodibility due to soil type and/or land use. The mini rainfall simulator was used recently in a study on soil erosion in olive groves (Ferrandina-Italy). The propensity to erosion of a steep rain-fed olive grove (mean slope ~10%) with a sandy loam soil was evaluated by measuring runoff and sediment load under extreme rain events. Two types of soil management were compared: spontaneous grass as a ground cover (GC) and tillage (1 day (T1) and 10 days after tillage (T2)). Results indicate that groundcover reduced surface runoff to approximately one-third and soil-losses to zero compared with T1. The runoff between the two tilled plots was similar, although runoff on T1 plots increased steadily over time whereas runoff on T2 plots remained stable.

Factors influencing real time internal structural visualization and dynamic process monitoring in plants using synchrotron-based phase contrast X-ray imaging

PubMed Central

Karunakaran, Chithra; Lahlali, Rachid; Zhu, Ning; Webb, Adam M.; Schmidt, Marina; Fransishyn, Kyle; Belev, George; Wysokinski, Tomasz; Olson, Jeremy; Cooper, David M. L.; Hallin, Emil

2015-01-01

Minimally invasive investigation of plant parts (root, stem, leaves, and flower) has good potential to elucidate the dynamics of plant growth, morphology, physiology, and root-rhizosphere interactions. Laboratory based absorption X-ray imaging and computed tomography (CT) systems are extensively used for in situ feasibility studies of plants grown in natural and artificial soil. These techniques have challenges such as low contrast between soil pore space and roots, long X-ray imaging time, and low spatial resolution. In this study, the use of synchrotron (SR) based phase contrast X-ray imaging (PCI) has been demonstrated as a minimally invasive technique for imaging plants. Above ground plant parts and roots of 10 day old canola and wheat seedlings grown in sandy clay loam soil were successfully scanned and reconstructed. Results confirmed that SR-PCI can deliver good quality images to study dynamic and real time processes such as cavitation and water-refilling in plants. The advantages of SR-PCI, effect of X-ray energy, and effective pixel size to study plant samples have been demonstrated. The use of contrast agents to monitor physiological processes in plants was also investigated and discussed. PMID:26183486

Spatial variation of corn canopy temperature as dependent upon soil texture and crop rooting characteristics

NASA Technical Reports Server (NTRS)

Choudhury, B. J.

1983-01-01

A soil plant atmosphere model for corn (Zea mays L.) together with the scaling theory for soil hydraulic heterogeneity are used to study the sensitivity of spatial variation of canopy temperature to field averaged soil texture and crop rooting characteristics. The soil plant atmosphere model explicitly solves a continuity equation for water flux resulting from root water uptake, changes in plant water storage and transpirational flux. Dynamical equations for root zone soil water potential and the plant water storage models the progressive drying of soil, and day time dehydration and night time hydration of the crop. The statistic of scaling parameter which describes the spatial variation of soil hydraulic conductivity and matric potential is assumed to be independent of soil texture class. The field averaged soil hydraulic characteristics are chosen to be representative of loamy sand and clay loam soils. Two rooting characteristics are chosen, one shallow and the other deep rooted. The simulation shows that the range of canopy temperatures in the clayey soil is less than 1K, but for the sandy soil the range is about 2.5 and 5.0 K, respectively, for the shallow and deep rooted crops.

Traditional pattern of cashew cultivation : A lesson from Sumenep-Madura, Indonesia

NASA Astrophysics Data System (ADS)

Jadid, Nurul; Sutikno, Dewi, Dyah Santhi; Nurhidayati, Tutik; Abdulgani, Nurlita; Muzaki, Farid Kamal; Arraniry, Byan Arasyi; Mardika, Rizal Kharisma; Rakhman, R. Yuvita

2017-11-01

Belonging to the Anacardiaceae family, the cashew tree (Anacardium Occidentale, Linn.) is one of the important tropical plants that possess high economic value. This plant is commonly grown in Indonesian regions including Sumenep, Madura, where the red sandy loam type of soil is commonly present. This study aims to obtain rough data on the pattern of cashew cultivation and identify the cashew cultivation knowledge of local communities. Data were taken in Bringin village, Sumenep-Madura. Our field survey showed that the cashew's cultivation pattern in this village applies the so-called traditional organic farming. Cashew trees are planted along the boundaries of the owner's farm field, functioning as a fence of their farm. Nevertheless, our survey also indicated that this pattern of cultivation is still below standard of cultivation. The planting distance between the cashew trees with one another is relatively close (< 5 meters), causing the cashew branches to overlap with each other. Moreover, we observed that there was no rejuvenation of old cashew trees. Finally, knowledge of the community about post-harvest processing is limited. Therefore, we suggest that educating the community about good standard cashew cultivation is required to improve productivity as well as the quality of cashew nuts.

Epidemiological investigations into multiple sclerosis in southern Hesse. II. The distribution of cases in relation to exogenous features.

PubMed

Lauer, K; Firnhaber, W

1984-10-01

In order to discover possible exogenous variables associated with a higher multiple sclerosis risk, the distribution of cases with definite and probable multiple sclerosis ascertained in the course of a micro-epidemiologic study in Southern Hesse was evaluated and compared with some environmental factors. The prevalence in 1980, the prevalence of cases with disease-onset within the region according to locality of onset and the rate of native Southern Hesse patients according to childhood residence all showed a similar geographical distribution, with the highest values in the south-eastern, mountainous part of the region. This district has a lower annual mean temperature, more annual snow-days and a higher annual precipitation compared to the remaining area. A statistical comparison revealed no association with industrial or agricultural activities, with a particular type of land use, with cattle, pig- or horse-breeding, or with sanitary or housing standards. On the other hand, a slight association with the soil type could be demonstrated, with higher rates on loam and clay subsoils when compared to predominantly sandy regions. Whether this finding has any significance or not remains to be clarified.

Reduction of root-knot nematode, Meloidogyne javanica, and ozone mass transfer in soil treated with ozone.

PubMed

Qiu, Jinya Jack; Westerdahl, Becky B; Pryor, Alan

2009-09-01

Ozone gas (O₃) is a reactive oxidizing agent with biocidal properties. Because of the current phasing out of methyl bromide, investigations on the use of ozone gas as a soil-fumigant were conducted. Ozone gas was produced at a concentration of 1% in air by a conventional electrical discharge O₃ generator. Two O₃ dosages and three gas flow rates were tested on a sandy loam soil collected from a tomato field that had a resident population of root knot nematodes, Meloidogyne javanica. At dosages equivalent to 50 and 250 kg of O₃/ha, M. javanica were reduced by 24% and 68%, and free-living nematodes by 19% and 52%, respectively. The reduction for both M. javanica and free-living nematodes was dosage dependent and flow rate independent. The rates of O₃ mass transfer (OMT) through three soils of different texture were greater at low and high moisture levels than at intermediate ones. At any one soil moisture level, the OMT rate varied with soil texture and soil organic matter content. Results suggest that soil texture, moisture, and organic matter content should be considered in determining O₃ dosage needed for effective nematode control.

Fluridone: a combination germination stimulant and herbicide for problem fields?

PubMed

Goggin, Danica E; Powles, Stephen B

2014-09-01

Problem weeds in agriculture, such as Lolium rigidum Gaud., owe some of their success to their large and dormant seed banks, which permit germination throughout a crop-growing season. Dormant weed seed banks could be greatly depleted by application of a chemical that stimulates early-season germination and then kills the young seedlings. Fluridone, a phytoene desaturase-inhibiting herbicide that can also break seed dormancy, was assessed for its efficacy in this regard. The germination of fluridone-treated Lolium rigidum seeds was stimulated on soils with low organic matter, and almost 100% seedling mortality was observed, while the treatment was only moderately effective on a high-organic-matter potting mix. Seedlings from wheat, canola, common bean and chickpea seeds sown on fluridone-treated sandy loam were bleached and did not survive, but lupins and field peas grew normally. This proof-of-concept study with fluridone suggests that it may be possible to design safe and effective molecules that act as germination stimulants plus herbicides in a range of crop and soil types: a potentially novel way of utilising herbicides to stimulate seed bank germination and a valuable addition to an integrated weed management system. © 2014 Society of Chemical Industry.

Pore-scale water dynamics during drying and the impacts of structure and surface wettability

NASA Astrophysics Data System (ADS)

Cruz, Brian C.; Furrer, Jessica M.; Guo, Yi-Syuan; Dougherty, Daniel; Hinestroza, Hector F.; Hernandez, Jhoan S.; Gage, Daniel J.; Cho, Yong Ku; Shor, Leslie M.

2017-07-01

Plants and microbes secrete mucilage into soil during dry conditions, which can alter soil structure and increase contact angle. Structured soils exhibit a broad pore size distribution with many small and many large pores, and strong capillary forces in narrow pores can retain moisture in soil aggregates. Meanwhile, contact angle determines the water repellency of soils, which can result in suppressed evaporation rates. Although they are often studied independently, both structure and contact angle influence water movement, distribution, and retention in soils. Here drying experiments were conducted using soil micromodels patterned to emulate different aggregation states of a sandy loam soil. Micromodels were treated to exhibit contact angles representative of those in bulk soil (8.4° ± 1.9°) and the rhizosphere (65° ± 9.2°). Drying was simulated using a lattice Boltzmann single-component, multiphase model. In our experiments, micromodels with higher contact angle surfaces took 4 times longer to completely dry versus micromodels with lower contact angle surfaces. Microstructure influenced drying rate as a function of saturation and controlled the spatial distribution of moisture within micromodels. Lattice Boltzmann simulations accurately predicted pore-scale moisture retention patterns within micromodels with different structures and contact angles.

Functional and environmental assessment of the urboecosystems designed in the biologically reclamated landfill with industrial wastes (in Ryazan city)

NASA Astrophysics Data System (ADS)

Karyakin, Alexey; Vasenev, Ivan; Karyakina, Svetlana

2015-04-01

Regional environmental bodies' ability to understand, model and predict their soil cover environmental functions are especially important in case of landfill reclamation. The special attention has to be done to landfills with industrial wastes created earlier in frame of big city - comparatively closed to their residential areas. Dominated in Ryazan region sandy loam gray forest soils with not so high soil organic matter content and soil exchange capacity determine additional problems with landfill biological reclamation and continuous sustainable vegetation cover development. The modern environmental monitoring system has been developed in the big landfill with tanning industrial wastes from the biggest in Europe tannery to develop recommendation on the environmentally friendly reclamation technologies adapted to concrete landscape conditions and functional features of 2 m fresh soil-ground coating the landfill surface. More detailed monitoring system has to be developed to assess the regulatory environmental functions of the regenerated soil cover to minimize the reclamated landfill' negative impacts on the urban ecosystem air, surface and ground water quality. Obtained result will be useful for similar landfills with tanning industrial wastes environmental impact assessment and smart design.

Cordia dichotoma G. Forst. : Bioecology and population density

NASA Astrophysics Data System (ADS)

Rahayu, E. S.; Martin, P.; Dewi, N. K.; Kurniawan, F. H.

2017-04-01

Kendal tree is declared as an identity flora of Kendal Regency, Central Java, Indonesia. It is predicted as a rare species; most of the local people do not know the existence of this tree. The study aimed to describe some aspects of bioecology and a population density of Kendal tree. An explorative study was conducted from March to July 2016, through interview, observation, and literature review. The respondents were determined by purposive and snowball sampling methods. The data were analysed descriptively. Results showed that there were very limited numbers (only five trees) of Kendal tree throughout Kendal Regency. The species was identified as Cordia dichotoma G. Forst. The tree is 3-15 m in height. The leaves are simple and arranged spirally, inflorescence dichotomous, bisexual, with five gamosepalous and gamopetalous. Generative reproduction occurred at a low rate. The tree grew optimally in a dusty, sandy loam soil, pH 6.0-6.5 with a temperature ranged from 27-34 °C, a light intensity of 450-1580 lux, and an altitude of about 10 meters above sea level. In conclusion, C. dichotoma is a rare plant in Kendal Regency. This plant needs an alternative method of propagation, regeneration and conservation using in vitro technique.

Biodegradation, sorption, and transport of 2,4-dichlorophenoxyacetic acid in saturated and unsaturated soils.

PubMed Central

Estrella, M R; Brusseau, M L; Maier, R S; Pepper, I L; Wierenga, P J; Miller, R M

1993-01-01

The fate of an organic contaminant in soil depends on many factors, including sorption, biodegradation, and transport. The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) was used as a model compound to illustrate the impact of these interacting factors on the fate of an organic contaminant. Batch and column experiments performed with a sandy loam soil mixture under saturated and unsaturated conditions were used to determine the effects of sorption and biodegradation on the fate and transport of 2,4-D. Sorption of 2,4-D was found to have a slight but significant effect on transport of 2,4-D under saturated conditions (retardation factor, 1.8) and unsaturated conditions (retardation factor, 3.4). Biodegradation of 2,4-D was extensive under both batch and column conditions and was found to have a significant impact on 2,4-D transport in column experiments. In batch experiments, complete mineralization of 2,4-D (100 mg kg-1) occurred over a 4-day period following a 3-day lag phase under both saturated and unsaturated conditions. The biodegradation rate parameters calculated for batch experiments were found to be significantly different from those estimated for column experiments. PMID:8285717

Postharvest response of oranges of ethylene

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

Aharoni, Y.; Lattar, F.S.; Monselise, S.P.

1969-01-01

Since the effect of ethylene on the respiration rate of young unripe oranges has not yet been described, experiments were carried out to study the respiratory response of such fruits to ethylene. Oranges (Citrus sinensis (L.) Osbeck) of the Washington navel, Shamouti and Valencia varieties, growing on a sandy loam near Rehovot, Israel, were picked in June, July, September, December and January. Immediately after picking, they were weighed, placed in glass jars, and stored at 20/sup 0/. Each experiment comprised 12 jars, 4 for each variety. A constant stream (200 ml/min) of air containing 20 ppm of ethylene was runmore » through the jars. The respiration rate was measured by the amount of CO/sub 2/ evolved by the fruits, and based on a fresh weight unit. The results show that in all 3 varieties, ethylene caused an immediate rise in respiration rate, at all stages of development tested, regardless of whether it was applied from the beginning of the test or after a certain period of storage in air. The pattern of response to ethylene of young unripe oranges (picked in June, July, and September) was therefore similar to that of ripe ones (picked in December and January).« less

Automated Passive Capillary Lysimeters for Estimating Water Drainage in the Vadose Zone

NASA Astrophysics Data System (ADS)

Jabro, J.; Evans, R.

2009-04-01

In this study, we demonstrated and evaluated the performance and accuracy of an automated PCAP lysimeters that we designed for in-situ continuous measuring and estimating of drainage water below the rootzone of a sugarbeet-potato-barley rotation under two irrigation frequencies. Twelve automated PCAPs with sampling surface dimensions of 31 cm width * 91 cm long and 87 cm in height were placed 90 cm below the soil surface in a Lihen sandy loam. Our state-of-the-art design incorporated Bluetooth wireless technology to enable an automated datalogger to transmit drainage water data simultaneously every 15 minutes to a remote host and had a greater efficiency than other types of lysimeters. It also offered a significantly larger coverage area (2700 cm2) than similarly designed vadose zone lysimeters. The cumulative manually extracted drainage water was compared with the cumulative volume of drainage water recorded by the datalogger from the tipping bucket using several statistical methods. Our results indicated that our automated PCAPs are accurate and provided convenient means for estimating water drainage in the vadose zone without the need for costly and manually time-consuming supportive systems.

Isothermal and non-isothermal infiltration and deuterium transport: a case study on undisturbed soil column from headwater catchment

NASA Astrophysics Data System (ADS)

Sobotkova, Martina; Snehota, Michal; Tesar, Miroslav

2017-04-01

Isothermal and non-isothermal infiltration experiments with tracer breakthrough were carried out in the laboratory on intact column of sandy loam soil taken from Roklan site (Sumava Mountains, Czech Republic). In the case of isothermal experiment, the temperature of infiltrating water was almost equal to the initial temperature of the sample. For the non-isothermal case the infiltration was performed using water approximately 10 °C colder than was the initial temperature of soil sample. The experiments were otherwise conducted under the same initial and boundary conditions. Pressure heads and temperatures in two depths (8.8 and 15.3 cm) inside the soil were monitored as well as the temperature of water entering and leaving the sample. Water drained freely through the perforated plate at the bottom of the sample by gravity and outflow was measured using tipping bucket flowmeter. Permeability of the sample calculated for steady state stages of the experiment showed that significant difference between water flow rates recorded during two experiment could not be justified only by temperature induced changes of water viscosity and density. Results of deuterium breakthrough were nearly identical for isothermal and non-isothermal conditions.

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

Bhattacharya, N.C.; Biswas, P.K.; Hileman, D.R.

During the Summer of 1985, studies were conducted on sweet potato plants in open top chambers and open field plots with CO/sub 2/ concentrations of +0, +75, +150 and +300 ..mu..l l/sup -1/ above ambient level. Sweet potato seedlings (cv. Georgia Jet) were planted singly in pots containing 23 kg of Norfolk sandy loam soil (Typic Paleudult). A group of five plants at each CO/sub 2/ concentrations were subjected to water stress for 10 and 15 days during the growth period of 40 and 75 days after planting. A comparison between stress and well watered plants showed an increase inmore » leaf area and tuber yield with CO/sub 2/ enrichment up to +150 ..mu..l l/sup -1/ CO/sub 2/ in stress plants, and +75 ..mu..l l/sup -1/ in well watered plants at 90 day harvest. However, leaf area as well as dry weights of shoots and tubers were greater in well watered than in stress plants. The root to shoot ratio was found to be higher in stress plants than in well watered plants in each CO/sub 2/ concentrations and it was most pronounced in +75 ..mu..l l/sup -1/ CO/sub 2/ in stressed plants.« less

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

In Russia quality standards of contaminated substances values in environment consist of ecological and sanitary rate-setting. The sanitary risk assessment base on potential risk that contaminants pose to protect human beings. The main purpose of the ecological risk assessment is to protect ecosystem. To determine negative influence on living organisms in the sanitary risk assessment in Russia we use MPC. This value of contaminants show how substances affected on different part of environment, biological activity and soil processes. The ecological risk assessment based on comparison compounds concentration with background concentration for definite territories. Taking into account high interval of microelements value in soils, we suggest using statistic method for determination of concentration levels of chemical elements concentration in soils of Russia. This method is based on determination middle levels of elements content in natural condition. The top limit of middle chemical elements concentration in soils is value, which exceed middle regional background level in three times standard deviation. The top limit of natural concentration excess we can explain as anthropogenic impact. At first we study changing in the middle content value of microelements in soils of geographic regions in European part of Russia on the basis of cartographical analysis. Cartographical analysis showed that the soil of mountainous and mountain surrounding regions is enriched with microelements. On the plain territory of European part of Russia for most of microelements was noticed general direction of increasing their concentration in soils from north to south, also in the same direction soil clay content rise for majority of soils. For all other territories a clear connection has been noticed between the distribution of sand sediment. By our own investigation and data from scientific literature data base was created. This data base consist of following soil properties: texture, 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.

Application of TREECS to Small Arms Firing Ranges at Fort Leonard Wood, MO

DTIC Science & Technology

2013-12-01

edited as necessary. The crop management factors (C) of the Universal Soil Loss Equation ( USLE ) were adjusted based upon the land-use description...ranges from approximately 750 to 1,150 feet above sea level near the northeastern installation boundary. The soils located at FLW are formed in the...official U.S. Department of Agriculture (USDA) soil types have been identified at FLW: Clarksville Gravelly Loam, Lebanon Silt Loam, and Huntington Loam

Environmental Assessment, United States Air Force Proposed Lease Replacement for Scandia Elementary School, Travis Air Force Base, California

DTIC Science & Technology

2015-09-01

brown, and light gray loam 19-inches thick. The subsoil is mottled, light yellowish brown, yellowish brown, and pale brown clay 41-inches thick...areas of Solano loam and Pescadero clay loam. The Antioch soil has slightly concave slopes, and the San Ysidro soil has slightly convex slopes (Web...Infrastructure and utilities include transportation, water supply, sanitary sewage/wastewater natural gas, electrical, communications, and liquid fuels

Impact of landform and type of land use on soils developed over granite in the monsoonal climate of North-East India

NASA Astrophysics Data System (ADS)

Prokop, Paweł; Kruczkowska, Bogusława; Jones Syiemlieh, Hiambok; Bucała, Anna

2016-04-01

Soil properties are determined by the factors such climate, organisms, topography, geology, and time. Despite human activity will be recognized as part of biotic factors or distinct from other organisms it change soil directly or indirectly by changing both soil morphology and the underlying soil-forming processes. Thus it is difficult to distinguish soil properties modified only due to human impact. A small hilly catchment (3.9 km2) at an altitude of 1750-1800 m a.s.l. was selected for the investigation of landform and land use impact on soil properties. The climate is monsoonal with 14oC of mean annual temperature and 2400 mm of mean annual rainfall. The catchment is underlain by deeply weathered (up to 20 m) granite with abundant corestones embedded in sandy grus. Soils have been classified as sandy-loam and silty-loam Ultisols. Site has relatively uniform climate and parent material, so that a large proportion of the local soil variation can be attributed to landforms and land use changes within them. Thirty soil samples from topsoil (depth up to10 cm) were analysed from two landforms: flat ridge and the middle part of 150 m length slope (15o) with three types of land use: natural deciduous forest, cultivated land (potatoes, cabbage) and 20-years old pine forest on former cultivated land. Physical (texture, bulk density) and chemical (pH, C, N, P, K, CEC) soil properties were analysed. Significant differences between the means of soil properties were identified using the t-statistics, with a level of probability of 5%. Impact of landform on topsoil properties was visible under all three land use types. Soil under natural deciduous forest on flat ridge has statistically significant less sand, higher content of C and N in comparison to soil profile localized on slope. The differences between ridge and slope under pine forest and cultivated land were limited to some chemical properties such content of C, N and CEC, while statistically significant differences in physical properties were not observed due to homogenization of topsoil during tillage. Contrasts in soil properties between three types of land use within the flat ridge were smaller than the contrast on slope. Soil under pine forest has highest pH and C, N content both within ridge (4.8, 4.24%, 0.37%) and slope (4.8, 3.46%, 0.27%) in comparison to natural deciduous forest (ridge 4.4, 3.42, 0.27%; slope 4.6, 2.32%, 0.20%) and agricultural land (ridge 4.7, 2.94%, 0.27%; slope 4.5, 2.43%, 0.23%). This indicates relatively fast recovery of topsoil chemical properties on the former cultivated land. The effects of cultivation on deep weathered granites, despite severe erosion on slopes, are less negative for environment than on surrounding areas built of quartzites with limited thickness of parent material.

Development of a new medium frequency EM device: Mapping soil water content variations using electrical conductivity and dielectric permittivity

NASA Astrophysics Data System (ADS)

Kessouri, P.; Buvat, S.; Tabbagh, A.

2012-12-01

Both electrical conductivity and dielectric permittivity of soil are influenced by its water content. Dielectric permittivity is usually measured in the high frequency range, using GPR or TDR, where the sensitivity to water content is high. However, its evaluation is limited by a low investigation depth, especially for clay rich soils. Electrical conductivity is closely related not only to soil water content, but also to clay content and soil structure. A simultaneous estimation of these electrical parameters can allow the mapping of soil water content variations for an investigation depth close to 1m. In order to estimate simultaneously both soil electrical conductivity and dielectric permittivity, an electromagnetic device working in the medium frequency range (between 100 kHz and 10 MHz) has been designed. We adopted Slingram geometry for the EM prototype: its PERP configuration (vertical transmission loop Tx and horizontal measuring loop Rx) was defined using 1D ground models. As the required investigation depth is around 1m, the coil spacing was fixed to 1.2m. This prototype works in a frequency range between 1 and 5 MHz. After calibration, we tested the response of prototype to objects with known properties. The first in situ measurements were led on experimental sites with different types of soils and different water content variations (artificially created or natural): sandy alluvium on a plot of INRA (French National Institute for Agricultural Research) in Orléans (Centre, France), a clay-loam soil on an experimental site in Estrée-Mons (Picardie, France) and fractured limestone at the vicinity of Grand (Vosges, France). In the case of the sandy alluvium, the values of dielectric permittivity measured are close to those of HF permittivity and allow the use of existing theoretical models to determine the soil water content. For soils containing higher amount of clay, the coupled information brought by the electrical conductivity and the dielectric permittivity is used. Variations of water content detected by the EM prototype are confirmed by additional DC electrical profiling and direct mass water content measurements along depth. For the clay-loam soil, containing more than 20% of clay, the relative dielectric permittivity values, ranging from 63 to 138, are much higher than those expected in the high frequency range (above 20 MHz, the highest measured permittivity is equal to 81 for water). In the medium frequency range, those values are very likely due to interfacial polarization. This effect, also known as Maxwell-Wagner polarization, should increase with the soil clay content. The first measuring trial is coherent with the gravimetric water content as well as DC electrical profiling measurements. For a clay rich soil, the EM prototype is able to detect water content variations for an investigation depth close to 1m with both electrical conductivity and dielectric permittivity in the medium frequency range. Other field experiments are scheduled to confirm these results on other types of soils.

Beach disturbance caused by off-road vehicles (ORVs) on sandy shores: relationship with traffic volumes and a new method to quantify impacts using image-based data acquisition and analysis.

PubMed

Schlacher, Thomas A; Morrison, Jennifer M

2008-09-01

Vehicles cause environmental damage on sandy beaches, including physical displacement and compaction of the sediment. Such physical habitat disturbance provides a relatively simple indicator of ORV-related impacts that is potentially useful in monitoring the efficacy of beach traffic management interventions; such interventions also require data on the relationship between traffic volumes and the resulting levels of impact. Here we determined how the extent of beach disturbance is linked to traffic volumes and tested the utility of image-based data acquisition to monitor beach surfaces. Experimental traffic application resulted in disturbance effects ranging from 15% of the intertidal zone being rutted after 10 vehicle passes to 85% after 100 passes. A new camera platform, specifically designed for beach surveys, was field tested and the resulting image-based data compared with traditional line-intercept methods and in situ measurements using quadrats. All techniques gave similar results in terms of quantifying the relationship between traffic intensity and beach disturbance. However, the physical, in situ measurements, using quadrats, generally produced higher (+4.68%) estimates than photos taken with the camera platform coupled with off-site image analysis. Image-based methods can be more costly, but in politically and socially sensitive monitoring applications, such as ORV use on sandy beaches, they are superior in providing unbiased and permanent records of environmental conditions in relation to anthropogenic pressures.

Method for Detection and Enumeration of Cryptosporidium parvum Oocysts in Feces, Manures, and Soils

PubMed Central

Kuczynska, Ewa; Shelton, Daniel R.

1999-01-01

Eight concentration and purification methods were evaluated to determine percentages of recovery of Cryptosporidium parvum oocysts from calf feces. The NaCl flotation method generally resulted in the highest percentages of recovery. Based on the percentages of recovery, the amounts of fecal debris in the final oocyst preparations, the relatively short processing time (<3 h), and the low expense, the NaCl flotation method was chosen for further evaluation. Extraction efficiency was evaluated by using oocyst concentrations of 25, 50, 102, 103, 104, and 105 oocysts g of bovine feces−1. The percentages of recovery ranged from 10.8% (25 oocysts g−1) to 17.0% (104 oocysts g−1) (r2 = 0.996). A conservative estimate of the detection limit for bovine feces is ca. 30 oocysts g of feces−1. Percentages of recovery were determined for six different types of animal feces (cow, horse, pig, sheep, deer, and chicken feces) at a single oocyst concentration (104 oocysts g−1). The percentages of recovery were highest for bovine feces (17.0%) and lowest for chicken feces (3.2%). Percentages of recovery were determined for bovine manure after 3 to 7 days of storage. The percentages of recovery ranged from 1.9 to 3.5% depending on the oocyst concentration, the time of storage, and the dispersing solution. The percentages of oocyst recovery from soils were evaluated by using different flotation solutions (NaCl, cold sucrose, ZnSO4), different dispersing solutions (Triton X-100, Tween 80, Tris plus Tween 80), different dispersion techniques (magnetic stirring, sonication, blending), and different dispersion times (5, 15, and 30 min). Twenty-five-gram soil samples were used to reduce the spatial variability. The highest percentages of recovery were obtained when we used 50 mM Tris–0.5% Tween 80 as the dispersing solution, dispersion for 15 min by stirring, and saturated NaCl as the flotation solution. The percentages of oocyst recovery from freshly spiked sandy loam, silty clay loam, and clay loam soils were ca. 12 to 18, 8, and 6%, respectively. The theoretical detection limits were ca. 1 to 2 oocysts g of soil−1 depending on the soil type. The percentages of recovery without dispersant (distilled H2O or phosphate-buffered saline) were less than 0.1%, which indicated that oocysts adhere to soil particles. The percentages of recovery decreased with storage time, although the addition of dispersant (Tris-Tween 80) before storage appeared to partially prevent adhesion. These data indicate that the NaCl flotation method is suitable for routine detection and enumeration of oocysts from feces, manures, soils, or soil-manure mixtures. PMID:10388670

Acute and chronic toxicity of the new explosive CL-20 to the earthworm (Eisenia andrei) exposed to amended natural soils.

PubMed

Robidoux, Pierre Yves; Sunahara, Geoffrey I; Savard, Kathleen; Berthelot, Yann; Dodard, Sabine; Martel, Majorie; Gong, Ping; Hawari, Jalal

2004-04-01

Monocyclic nitramine explosives such as 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) are toxic to a number of ecological receptors, including earthworms. The polycyclic nitramine CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane) is a powerful explosive that may replace RDX and HMX, but its toxicity is not known. In the present study, the lethal and sublethal toxicities of CL-20 to the earthworm (Eisenia andrei) are evaluated. Two natural soils, a natural sandy forest soil (designated RacFor2002) taken in the Montreal area (QC, Canada; 20% organic carbon, pH 7.2) and a Sassafras sandy loam soil (SSL) taken on the property of U.S. Army Aberdeen Proving Ground (Edgewood, MD, USA; 0.33% organic carbon, pH 5.1), were used. Results showed that CL-20 was not lethal at concentrations of 125 mg/kg or less in the RacFor2002 soil but was lethal at concentrations of 90.7 mg/kg or greater in the SSL soil. Effects on the reproduction parameters such as a decrease in the number of juveniles after 56 d of exposure were observed at the initial CL-20 concentration of 1.6 mg/kg or greater in the RacFor2002 soil, compared to 0.2 mg/kg or greater in the SSL soil. Moreover, low concentrations of CL-20 in SSL soil (approximately 0.1 mg/kg; nominal concentration) were found to reduce the fertility of earthworms. Taken together, the present results show that CL-20 is a reproductive toxicant to the earthworm, with lethal effects at higher concentrations. Its toxicity can be decreased in soils favoring CL-20 adsorption (high organic carbon content).

Study of processes influencing bioavailability of pesticides in wood-soil systems: Effect of different factors.

PubMed

Marín-Benito, J M; Herrero-Hernández, E; Rodríguez-Cruz, M S; Arienzo, M; Sánchez-Martín, M J

2017-05-01

Lignocellulosic wastes and by-products containing lignin are now available in large amounts from forestry and industrial activities, and could be promising organic materials for the biosorption of pesticides by soils in order to reduce point-source pollution. Adding these materials to soil requires understanding the process of pesticide sorption-desorption by wood-soils, as sorption capacity could increase, with changes in pesticide bioavailability and final fate. The objective of this work was to study the effect that pine and oak wood added to soils had on the sorption/desorption of the pesticides linuron, alachlor, and metalaxyl. Experiments were conducted with two sandy loam and sandy clay soils each amended with two wood doses (5% and 50%) after different incubation times (0, 5 and 12 months). A low wood dose (5%) had no significant impact on the sorption (K f ) of alachlor, but K f increased for linuron (up to 5.4-1.7 times) and metalaxyl (up to 4.4 and 8.6 times) in all wood-soil systems. The results were not significantly different after different incubation times. The desorption results indicated that wood decreases the sorption irreversibility of alachlor, and increases that of linuron and metalaxyl, with a varying effect of the wood-soil incubation time. The addition of a high wood dose to soil (50%) was more significant for increasing the sorption of all the pesticides, and the sorbed amounts remaining after desorption (>49% for linuron, >33% for alachlor and >6% for metalaxyl), although there was no apparent discrimination between the two types of woods. The role of the nature of the organic carbón (K oc values) for sorption was evidenced for alachlor and metalaxyl, but not for linuron. These outcomes are of interest for extending wood application to soil as a barrier for avoiding environmental risk by point-source pollution due to the use and management of pesticides in farming systems. Copyright © 2017 Elsevier Inc. All rights reserved.

Preliminary assessment of soil erosion impact during forest restoration process

NASA Astrophysics Data System (ADS)

Lai, Yen-Jen; Chang, Cheng-Sheng; Tsao, Tsung-Ming; Wey, Tsong-Huei; Chiang, Po-Neng; Wang, Ya-Nan

2014-05-01

Taiwan has a fragile geology and steep terrain. The 921 earthquake, Typhoon Toraji, Typhoon Morakot, and the exploitation and use of the woodland by local residents have severely damaged the landscape and posed more severe challenges to the montane ecosystem. A land conservation project has been implemented by the Experimental Forest of National Taiwan University which reclaimed approximately 1,500 hectares of leased woodland from 2008 to 2010, primarily used to grow bamboo, tea trees, betel nut, fruit, and vegetable and about 1,298 hectares have been reforested. The process of forest restoration involves clear cutting, soil preparation and a six-year weeding and tending period which may affect the amount of soil erosion dramatically. This study tried to assess the impact of forest restoration from the perspective of soil erosion through leased-land recovery periods and would like to benefit the practical implementation of reforestation in the future. A new plantation reforested in the early 2013 and a nearby 29-year-old mature forest were chosen as experimental and comparison sites. A self-designed weir was set up in a small watershed of each site for the runoff and sediment yield observation. According to the observed results from May to August 2013, a raining season in Taiwan, the runoff and erosion would not as high as we expected, because the in-situ soil texture of both sites is sandy loam to sandy with high percentage of coarse fragment which increased the infiltration. There were around 200 kg to 250 kg of wet sand/soil yielded in mature forest during the hit of Typhoon Soulik while the rest of the time only suspended material be yielded at both sites. To further investigate the influence of the six-year weeding and tending period, long term observations are needed for a more completed assessment of soil erosion impact.

Managing Semi-Arid Rangelands for Carbon Storage: Grazing and Woody Encroachment Effects on Soil Carbon and Nitrogen

PubMed Central

Yusuf, Hasen M.; Treydte, Anna C.; Sauerborn, Jauchim

2015-01-01

High grazing intensity and wide-spread woody encroachment may strongly alter soil carbon (C) and nitrogen (N) pools. However, the direction and quantity of these changes have rarely been quantified in East African savanna ecosystem. As shifts in soil C and N pools might further potentially influence climate change mitigation, we quantified and compared soil organic carbon (SOC) and total soil nitrogen (TSN) content in enclosures and communal grazing lands across varying woody cover i.e. woody encroachment levels. Estimated mean SOC and TSN stocks at 0–40 cm depth varied across grazing regimes and among woody encroachment levels. The open grazing land at the heavily encroached site on sandy loam soil contained the least SOC (30 ± 2.1 Mg ha-1) and TSN (5 ± 0.57 Mg ha-1) while the enclosure at the least encroached site on sandy clay soil had the greatest mean SOC (81.0 ± 10.6 Mg ha-1) and TSN (9.2 ± 1.48 Mg ha-1). Soil OC and TSN did not differ with grazing exclusion at heavily encroached sites, but were twice as high inside enclosure compared to open grazing soils at low encroached sites. Mean SOC and TSN in soils of 0–20 cm depth were up to 120% higher than that of the 21–40 cm soil layer. Soil OC was positively related to TSN, cation exchange capacity (CEC), but negatively related to sand content. Our results show that soil OC and TSN stocks are affected by grazing, but the magnitude is largely influenced by woody encroachment and soil texture. We suggest that improving the herbaceous layer cover through a reduction in grazing and woody encroachment restriction are the key strategies for reducing SOC and TSN losses and, hence, for climate change mitigation in semi-arid rangelands. PMID:26461478

Field application of farmstead runoff to vegetated filter strips: surface and subsurface water quality assessment.

PubMed

Larson, Rebecca A; Safferman, Steven I

2012-01-01

Farmstead runoff poses significant environmental impacts to ground and surface waters. Three vegetated filter strips were assessed for the treatment of dairy farmstead runoff at the soil surface and subsurface at 0.3- or 0. 46-m and 0. 76-m depths for numerous storm events. A medium-sized Michigan dairy was retrofitted with two filter strips on sandy loam soil and a third filter strip was implemented on a small Michigan dairy with sandy soil to collect and treat runoff from feed storage, manure storage, and other impervious farmstead areas. All filter strips were able to eliminate surface runoff via infiltration for all storm events over the duration of the study, eliminating pollutant contributions to surface water. Subsurface effluent was monitored to determine the contributing groundwater concentrations of numerous pollutants including chemical oxygen demand (COD), metals, and nitrates. Subsurface samples have an average reduction of COD concentrations of 20, 11, and 85% for the medium dairy Filter Strip 1 (FS1), medium dairy Filter Strip 2 (FS2), and the small Michigan dairy respectively, resulting in average subsurface concentrations of 355, 3960, and 718 mg L COD. Similar reductions were noted for ammonia and total Kjeldahl nitrogen (TKN) in the subsurface effluent. The small Michigan dairy was able to reduce the pollutant leachate concentrations of COD, TKN, and ammonia over a range of influent concentrations. Increased influent concentrations in the medium Michigan dairy filter strips resulted in an increase in COD, TKN, and ammonia concentrations in the leachate. Manganese was leached from the native soils at all filter strips as evidenced by the increase in manganese concentrations in the leachate. Nitrate concentrations were above standard drinking water limits (10 mg L), averaging subsurface concentrations of 11, 45, and 25 mg L NO-N for FS1, FS2, and the small Michigan dairy, respectively. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

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.

A laboratory study of the persistence of carbofuran and its 3-hydroxy- and 3 keto-metabolites in sterile and natural mineral and organic soils.

PubMed

Miles, J R; Tu, C M; Harris, C R

1981-01-01

In a laboratory study, the persistence of carbofuran and its 3-hydroxy- and 3-keto-metabolites was examined separately over 16 wk in sterile and natural organic (muck) and mineral (loam) soils. Carbofuran was relatively persistent in sterile soils; at 8 wk 77% remained in the sterile muck and about 50% remained in the sterile loam. In the natural muck 25% of initial carbofuran remained at wk whereas in the natural loam carbofuran had completely disappeared by that time. The 3-ketocarbofuran was very short-lived even in the sterile muck where only 50% remained at 1 wk. The 3-hydroxycarbofuran degraded appreciably on zero day in the natural soils (with conversion to 3-keto-carbofuran) and about 90% had disappeared in 1 wk. A more detailed study of the persistence of 3-hydroxycarbofuran in the natural soils showed complete disappearance in 2 days in loam and in 3 days in muck. The 3-ketocarbofuran produced from the 3-hydroxy-carbofuran reached a maximum concentration in 1 day and then disappeared within 4 days in loam and about 1 wk in muck.

Effects of aluminium water treatment residuals, used as a soil amendment to control phosphorus mobility in agricultural soils.

PubMed

Ulén, Barbro; Etana, Ararso; Lindström, Bodil

2012-01-01

Phosphorus (P) leaching from agricultural soils is a serious environmental concern. Application of aluminium water treatment residuals (Al-WTRs) at a rate of 20 Mg ha(-1) to clay soils from central Sweden significantly increased mean topsoil P sorption index (PSI) from 4.6 to 5.5 μmol kg(-1) soil. Mean degree of P saturation in ammonium lactate extract (DPS-AL) significantly decreased from 17 to 13%, as did plant-available P (P-AL). Concentrations of dissolved reactive P (DRP) decreased by 10-85% in leaching water with Al-WTR treatments after exposure of topsoil lysimeters to simulated rain. Soil aggregate stability (AgS) for 15 test soils rarely improved. Three soils (clay loam, silty loam and loam sand) were tested in greenhouse pot experiments. Aluminium-WTR application of 15 or 30 ton ha(-1) to loam sand and a clay loam with P-AL values of 80-100 mg kg(-1) soil significantly increased growth of Italian ryegrass when fertilised with P but did not significantly affect growth of spring barley on any soil. Al-WTR should only be applied to soils with high P fertility where improved crop production is not required.

Evaluation of the mechanical properties of class-F fly ash.

PubMed

Kim, Bumjoo; Prezzi, Monica

2008-01-01

Coal-burning power plants in the United States (US) generate more than 70 million tons of fly ash as a by-product annually. Recycling large volumes of fly ash in geotechnical applications may offer an attractive alternative to the disposal problem as most of it is currently dumped in ponds or landfills. Class-F fly ash, resulting from burning of bituminous or anthracite coals, is the most common type of fly ash in the US. In the present study, the mechanical characteristics (compaction response, compressibility, and shear strength) of class-F fly ash were investigated by performing various laboratory tests (compaction test, one-dimensional compression test, direct shear test and consolidated-drained triaxial compression test) on fly ash samples collected from three power plants in the state of Indiana (US). Test results have shown that despite some morphological differences, class-F fly ash exhibits mechanical properties that are, in general, comparable to those observed in natural sandy soils.

Spatial and Temporal Pattern of Rift Valley Fever Outbreaks in Tanzania; 1930 to 2007

PubMed Central

Sindato, Calvin; Karimuribo, Esron D.; Pfeiffer, Dirk U.; Mboera, Leonard E. G.; Kivaria, Fredrick; Dautu, George; Bernard, Bett; Paweska, Janusz T.

2014-01-01

Background Rift Valley fever (RVF)-like disease was first reported in Tanzania more than eight decades ago and the last large outbreak of the disease occurred in 2006–07. This study investigates the spatial and temporal pattern of RVF outbreaks in Tanzania over the past 80 years in order to guide prevention and control strategies. Materials and Methods A retrospective study was carried out based on disease reporting data from Tanzania at district or village level. The data were sourced from the Ministries responsible for livestock and human health, Tanzania Meteorological Agency and research institutions involved in RVF surveillance and diagnosis. The spatial distribution of outbreaks was mapped using ArcGIS 10. The space-time permutation model was applied to identify clusters of cases, and a multivariable logistic regression model was used to identify risk factors associated with the occurrence of outbreaks in the district. Principal Findings RVF outbreaks were reported between December and June in 1930, 1947, 1957, 1960, 1963, 1968, 1977–79, 1989, 1997–98 and 2006–07 in 39.2% of the districts in Tanzania. There was statistically significant spatio-temporal clustering of outbreaks. RVF occurrence was associated with the eastern Rift Valley ecosystem (OR = 6.14, CI: 1.96, 19.28), total amount of rainfall of >405.4 mm (OR = 12.36, CI: 3.06, 49.88), soil texture (clay [OR = 8.76, CI: 2.52, 30.50], and loam [OR = 8.79, CI: 2.04, 37.82]). Conclusion/Significance RVF outbreaks were found to be distributed heterogeneously and transmission dynamics appeared to vary between areas. The sequence of outbreak waves, continuously cover more parts of the country. Whenever infection has been introduced into an area, it is likely to be involved in future outbreaks. The cases were more likely to be reported from the eastern Rift Valley than from the western Rift Valley ecosystem and from areas with clay and loam rather than sandy soil texture. PMID:24586433

Phytotoxicity of three plant-based biodiesels, unmodified castor oil, and Diesel fuel to alfalfa (Medicago sativa L.), lettuce (Lactuca sativa L.), radish (Raphanus sativus), and wheatgrass (Triticum aestivum).

PubMed

Bamgbose, Ifeoluwa; Anderson, Todd A

2015-12-01

The wide use of plant-based oils and their derivatives, in particular biodiesel, have increased extensively over the past decade to help alleviate demand for petroleum products and improve the greenhouse gas emissions profile of the transportation sector. Biodiesel is regarded as a clean burning alternative fuel produced from livestock feeds and various vegetable oils. Although in theory these animal and/or plant derived fuels should have less environmental impact in soil based on their simplified composition relative to Diesel, they pose an environmental risk like Diesel at high concentrations when disposed. The aim of the present study was to ascertain the phytotoxicity of three different plant-derived biodiesels relative to conventional Diesel. For phytotoxicological analysis, we used seeds of four crop plants, Medicago sativa, Lactuca sativa, Raphanus sativus, and Triticum aestivum to analyze the germination of seeds in contaminated soil samples. The toxicological experiment was conducted with two different soil textures: sandy loam soil and silt loam soil. The studied plant-based biodiesels were safflower methyl-ester, castor methyl ester, and castor ethyl-ester. Biodiesel toxicity was more evident at high concentrations, affecting the germination and survival of small-seeded plants to a greater extent. Tolerance of plants to the biodiesels varied between plant species and soil textures. With the exception of R. sativus, all plant species were affected and exhibited some sensitivity to the fuels, such as delayed seedling emergence and slow germination (average=10 days) at high soil concentrations (0.85% for Diesel and 1.76% for the biodiesels). Tolerance of plants to soil contamination had a species-specific nature, and on average, decreased in the following order: Raphanus sativus (0-20%)>Triticum aestivum (10-40%) ≥ Medicago sativa> Lactuca sativa (80-100%). Thus, we conclude that there is some phytotoxicity associated with plant-based biodiesels. Further, the findings of this study can be useful for selecting the least fuel-tolerant species as a soil contamination bio-indicator and for determining the risks of biodiesel contamination. Copyright © 2015 Elsevier Inc. All rights reserved.

Evaluation of N environmental risks on Andosols from an intensive dairy farming watershed using DNDC.

PubMed

Deng, Meihua; Bellingrath-Kimura, Sonoko D; Zeng, Lin; Hojito, Masayuki; Zhang, Tianzhu; Yoh, Muneoki

2015-04-15

Manure nitrogen (N) in the livestock sector has become a key driver of environmental change. The denitrification-decomposition (DNDC) model was used to evaluate N pollution strengths on Andosols with intensive dairy manure application in Upper Naka River Watershed, Japan. The calibrated model was capable of predicting Andosol N flows because the simulated soil mineral N content, soil nitrogen oxide (N2O) fluxes, denitrification rate, and crop N uptake matched the patterns and magnitudes of the field observations from a wide range of soil textures, as well as manure management and cropping systems. The simulations showed that current intensive manure application systems caused low crop N use efficiency and a large amount of NO3(-)-N leaching and N2O emission. The crop N use efficiency was 27%-42% and 37%-55% of input N for uplands and paddy rice, respectively. The uplands showed much more serious N environmental pollution risks with N leaching 123-362 kg N ha(-1) yr(-1) and N2O emissions 6.53-11.8 kg N ha(-1) yr(-1) than that in the lowland paddy rice with N leaching 17.4-103 kg N ha(-1) yr(-1) and N2O emissions 0.59-2.77 kg N ha(-1) yr(-1). Forage rice/barley crop systems have high N cleaning capability due to the greater crop N uptake which reached to 304 kg N ha(-1) yr(-1). High precipitation stimulated more NO3(-)-N leaching. Sandy soil also showed higher N leaching and was unsuitable for paddy rice. Slurry application stimulated more N2O emission than compost manure. To mitigate the current high N pollution, the critical N application rate was recommended to be approximately 380, 470, 640, and 390 kg N ha(-1) yr(-1) for loam sand planted with maize/grass, loam soil with maize/grass, forage rice/barley, and rice/fallow with winter manure application, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

Greenhouse gas emissions and soil properties following amendment with manure-derived biochars: Influence of pyrolysis temperature and feedstock type.

PubMed

Subedi, Raghunath; Taupe, Natalie; Pelissetti, Simone; Petruzzelli, Laura; Bertora, Chiara; Leahy, James J; Grignani, Carlo

2016-01-15

Manure-derived biochars can offer a potential option for the stabilization of manure, while mitigating climate change through carbon sequestration and the attenuation of nitrous oxide emission. A laboratory incubation study was conducted to assess the effects of four different manure-derived biochars produced from different feedstocks (poultry litter and swine manure) at different temperatures (400 or 600 °C). A commonly available standard wood chip biochar, produced at a greater temperature (1000 °C), and non-amended treatments were used as references. Two different soils (sandy and silt-loam) were amended with 2% (w/w) biochar on a dry soil weight basis (corresponding to 20 Mg ha(-1)), with the soil moisture being adjusted to 75% saturation level. After a pre-incubation period (21 days), 170 kg N ha(-1) of NH4NO3 fertilizer was added. Measurements of CO2, N2O, CH4 emissions and soil N mineralisation were carried out on different days during the 85 days of incubation. The net C mineralization and N2O emissions from both soils amended with poultry litter biochar at 400 °C were significantly greater than the other biochar treatments. Nitrate availability was greater in both soils in which the manure-derived biochar was used instead of the standard biochar. All of the biochars increased the pH of the silt-loam, sub-acid soil, but failed to improve the cation exchange capacities (CEC) in either soil. Total C and N, P, K and Mg (except Ca) were significantly increased in the manure-derived biochar amended soils, compared to the Control, and were positively correlated to the biochar nutrient contents. This study indicates that the soil application of biochar engenders effects that can vary considerably according to the biochar properties, as determined on the basis of the feedstock types and process conditions. Low-temperature biochar production from manure represents a possible way of producing a soil amendment that can stabilize C while supplying a significant quantity of nutrients. Copyright © 2015 Elsevier Ltd. All rights reserved.

The effect of soil texture on the degradation of textiles associated with buried bodies.

PubMed

Lowe, A C; Beresford, D V; Carter, D O; Gaspari, F; O'Brien, R C; Stuart, B H; Forbes, S L

2013-09-10

There are many factors which affect the rate of decomposition in a grave site including; the depth of burial, climatic conditions, physical conditions of the soil (e.g. texture, pH, moisture), and method of burial (e.g. clothing, wrappings). Clothing is often studied as a factor that can slow the rate of soft tissue decomposition. In contrast, the effect of soft tissue decomposition on the rate of textile degradation is usually reported as anecdotal evidence rather than being studied under controlled conditions. The majority of studies in this area have focused on the degradation of textiles buried directly in soil. The purpose of this study was to investigate the effect of soil texture on the degradation and/or preservation of textile materials associated with buried bodies. The study involved the burial of clothed domestic pig carcasses and control clothing in contrasting soil textures (silty clay loam, fine sand and fine sandy loam) at three field sites in southern Ontario, Canada. Graves were exhumed after 2, 12 and 14 months burial to observe the degree of degradation for both natural and synthetic textiles. Recovered textile samples were chemically analyzed using infrared (IR) spectroscopy and gas chromatography-mass spectrometry (GC-MS) to investigate the lipid decomposition by-products retained in the textiles. The findings of this study demonstrate that natural textile in contact with a buried decomposing body will be preserved for longer periods of time when compared to the same textile buried directly in soil and not in contact with a body. The soil texture did not visually impact the degree of degradation or preservation. Furthermore, the natural-synthetic textile blend was resistant to degradation, regardless of soil texture, contact with the body or time since deposition. Chemical analysis of the textiles using GC-MS correctly identified a lipid degradation profile consistent with the degree of soft tissue decomposition. Such information may be important for estimating time since deposition in instances where only grave goods and associated materials are recovered from a burial site. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Evaluation of Two Soil Water Redistribution Models (Finite Difference and Hourly Cascade Approach) Through The Comparison of Continuous field Sensor-Based Measurements

NASA Astrophysics Data System (ADS)

Ferreyra, R.; Stockle, C. O.; Huggins, D. R.

2014-12-01

Soil water storage and dynamics are of critical importance for a variety of processes in terrestrial ecosystems, including agriculture. Many of those systems are under significant pressure in terms of water availability and use. Therefore, assessing alternative scenarios through hydrological models is an increasingly valuable exercise. Soil water holding capacity is defined by the concepts of soil field capacity and plant available water, which are directly related to soil physical properties. Both concepts define the energy status of water in the root system and closely interact with plant physiological processes. Furthermore, these concepts play a key role in the environmental transport of nutrients and pollutants. Soil physical parameters (e.g. saturated hydraulic conductivity, total porosity and water release curve) are required as input for field-scale soil water redistribution models. These parameters are normally not easy to measure or monitor, and estimation through pedotransfer functions is often inadequate. Our objectives are to improve field-scale hydrological modeling by: (1) assessing new undisturbed methodologies for determining important soil physical parameters necessary for model inputs; and (2) evaluating model outputs, making a detailed specification of soil parameters and the particular boundary condition that are driving water movement under two contrasting environments. Soil physical properties (saturated hydraulic conductivity and determination of water release curves) were quantified using undisturbed laboratory methodologies for two different soil textural classes (silt loam and sandy loam) and used to evaluate two soil water redistribution models (finite difference solution and hourly cascade approach). We will report on model corroboration results performed using in situ, continuous, field measurements with soil water content capacitance probes and digital tensiometers. Here, natural drainage and water redistribution were monitored following a controlled water application where the study areas were isolated from other water inputs and outputs. We will also report on the assessment of two soil water sensors (Decagon Devices 5TM capacitance probe and UMS T4 tensiometers) for the two soil textural classes in terms of consistency and replicability.

Microbial Response to UV Exposure and Nitrogen Limitation in Desert Soil Crusts

NASA Astrophysics Data System (ADS)

Fulton, J. M.; Van Mooy, B. A.

2016-12-01

Microbiotic soil crusts have diverse biomarker distributions and C and N stable isotopic compositions that covary with soil type. Sparse plant cover and the relative lack of soil disturbance in arid/semi-arid landscapes allows populations of soil cyanobacteria to develop along with fungi and heterotrophic bacteria. Microbial communities in this extreme environment depend in part on the production of scytonemin, a UV protective pigment, by cyanobacteria near the top of the crust. N limitation of microbial growth also affects soil crust population dynamics, increasing the requirement of N2fixation by diazotrophic cyanobacteria. We collected 56 soil crust samples from 27 locations throughout the Great Salt Lake Desert, including four transects spanning high-elevation, erosion-dominated soils to lower elevation soils dominated by silt-accumulation. Erosion-dominated soil surfaces included rounded gravel and cobbles; in the interstices there were poorly-developed microbiotic crusts on sandy loam with low δ15N values near 0‰ that point toward microbial growth dependent on cyanobacterial N2 fixation. Nutrients regenerated by heterotrophic bacteria may have been eroded from the system, providing a positive feedback for N2 fixation. High scytonemin:chlorophyll a ratios suggest that cyanobacteria required enhanced protection from UV damage in these crusts. A similar increase in scytonemin:chlorophyll a ratio during soil crust rehydration experiments also points toward the importance of UV protection. Glycolipid:phospholipid ratios were lowest where N2 fixation was favored, however, suggesting that the cyanobacterial population was relatively small, possibly because of the metabolic cost of N2fixation. Microbiotic crusts on silt loam soils, on the other hand, had higher δ15N values between 3.5 and 7.8‰, consistent with heterotrophic growth and nutrient recycling. Lower scytonemin:chlorophyll a ratios suggest that relatively high photosynthetic activity was supported in these well-developed crusts. Vertical migration may have reduced the scytonemin requirement of cyanobacteria. Higher glycolipid:phospholipid ratios suggest that cyanobacteria and algae had greater relative abundance than heterotrophic bacteria in well-developed compared with erosion-dominated crusts.

Soil management practice in Croatian vineyard affect CO2 fluxes and soil degradation in trafficking zones. First results

NASA Astrophysics Data System (ADS)

Bogunovic, Igor; Bilandzija, Darija; Andabaka, Zeljko; Stupic, Domagoj; Cacic, Marija; Brezinscak, Luka; Maletic, Edi; Pereira, Paulo; Kisic, Ivica

2017-04-01

Vineyards represent one of the most degradation prone types of intensively managed land on Earth. Steep slopes encourage grape producers to adopt environmental friendly soil management like mulching or continuous no-tillage. In this context, producers have concerns about efficient fertilisation practices and water competitions between vine and grasses in continuous no-tillage inter rows. Vineyards in semi-humid areas like Continental Croatia mostly not suffer from water deficit during growth. Nevertheless, lack of research of different soil management practices open dilemma about soil compaction concerns in intensively trafficked soils in vineyard of semi-humid areas. Soil compaction, determined by bulk density (BD), soil water content (SWC) and CO2 fluxes from trafficked inter row positions were recorded in 2016 in an experiment in which four different soil management systems were compared in a vineyard raised on a silty clay loam soil, near Zagreb, Croatia: No-tillage (NT) system, continuous tillage (CT) and yearly inversed grass covered (INV-GC) and tillage managed (INV-T) inter rows are subjected to intensive traffic. Grape yield and must quality of grape variety Chardonnay was also monitored. Tractor traffic increased the soil BD at 0-10 and 10-20 cm, but especially at the 0-10 cm depth. CT treatment record lowest compaction at 0-10 cm because of tillage. Soil water content showed better conservation possibilities of INV-GC in drier period. In wet period SWC possibilities are similar between treatments. The results of soil compaction under different management indicate that vineyard soil differently response to traffic intensity and impact on microfauna activity and CO2 emissions. INV-GC and NT managed soils record lower CO2 fluxes from vineyard soil compared to CT and INV-T treatments. Management treatments did not statistically influenced on grape yields. Several years of investigation is needed to confirm the overall impact of different management treatments on the proportion of degradation process and their response to proportion of tractor circulation impacts.

Impact of soil organic carbon on monosodium methyl arsenate (MSMA) sorption and species transformation.

PubMed

Ou, Ling; Gannon, Travis W; Polizzotto, Matthew L

2017-11-01

Monosodium methyl arsenate (MSMA), a common arsenical herbicide, is a major contributor of anthropogenic arsenic (As) to the environment. Uncertainty about controls on MSMA fate and the rates and products of MSMA species transformation limits effective MSMA regulation and management. The main objectives of this research were to quantify the kinetics and mechanistic drivers of MSMA species transformation and removal from solution by soil. Laboratory MSMA incubation studies with two soils and varying soil organic carbon (SOC) levels were conducted. Arsenic removal from solution was more extensive and faster in sandy clay loam incubations than sand incubations, but for both systems, As removal was biphasic, with initially fast removal governed by sorption, followed by slower As removal limited by species transformation. Dimethylarsinic acid was the dominant product of species transformation at first, but inorganic As(V) was the ultimate transformation product by experiment ends. SOC decreased As removal and enhanced As species transformation, and SOC content had linear relationships with As removal rates (R 2  = 0.59-0.95) for each soil and reaction phase. These results reveal the importance of edaphic conditions on inorganic As production and overall mobility of As following MSMA use, and such information should be considered in MSMA management and regulatory decisions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Disruption rates for one vulnerable soil in Organ Pipe Cactus National Monument, Arizona, USA

USGS Publications Warehouse

Webb, Robert H.; Esque, Todd C.; Nussear, Kenneth E.; Sturm, Mark

2013-01-01

Rates of soil disruption from hikers and vehicle traffic are poorly known, particularly for arid landscapes. We conducted an experiment in Organ Pipe Cactus National Monument (ORPI) in western Arizona, USA, on an air-dry very fine sandy loam that is considered to be vulnerable to disruption. We created variable-pass tracks using hikers, an all-terrain vehicle (ATV), and a four-wheel drive vehicle (4WD) and measured changes in cross-track topography, penetration depth, and bulk density. Hikers (one pass = 5 hikers) increased bulk density and altered penetration depth but caused minimal surface disruption up to 100 passes; a minimum of 10 passes were required to overcome surface strength of this dry soil. Both ATV and 4WD traffic significantly disrupted the soil with one pass, creating deep ruts with increasing passes that rendered the 4WD trail impassable after 20 passes. Despite considerable soil loosening (dilation), bulk density increased in the vehicle trails, and lateral displacement created berms of loosened soil. This soil type, when dry, can sustain up to 10 passes of hikers but only one vehicle pass before significant soil disruption occurs; greater disruption is expected when soils are wet. Bulk density increased logarithmically with applied pressure from hikers, ATV, and 4WD.

Effects of Biosolid Soil Amendment on Heterodera glycines Populations

PubMed Central

Melakeberhan, H; Noel, G. R.

2006-01-01

The high degree of parasitic variability in Heterodera glycines and its distribution in a wide range of soybean production systems present multiple challenges for management, which necessitate increased understanding of the biology of H. glycines. Soil amendments are being considered either as stand-alone and/or as part of integrated management approaches. A recycled municipal biosolid with nutrition supplement and liming qualities, N-Viro Soil (NVS) has potential as a multi-purpose soil amendment. In three greenhouse experiments, the effects of 0, 1.0 or 4.0 g NVS/100 cm3 of sandy loam soil on three H. glycines populations (GN1, GN2 and GN3) were investigated on soybean grown for 557 ± 68 degree-days (base 10°C). The response of the three H. glycines populations to NVS treatment varied by experiment. The overall numbers of preadult stages and cysts generally decreased with increasing levels of NVS in all experiments, and the high rate was more effective than the low rate in suppressing H. glycines numbers. This suggests that the high NVS treatment can affect the three populations in the experimental soil type under controlled conditions. Field studies to determine efficacy of the soil amendment in a wide range of environments should be initiated. PMID:19259540

Modelling hydrology of a single bioretention system with HYDRUS-1D.

PubMed

Meng, Yingying; Wang, Huixiao; Chen, Jiangang; Zhang, Shuhan

2014-01-01

A study was carried out on the effectiveness of bioretention systems to abate stormwater using computer simulation. The hydrologic performance was simulated for two bioretention cells using HYDRUS-1D, and the simulation results were verified by field data of nearly four years. Using the validated model, the optimization of design parameters of rainfall return period, filter media depth and type, and surface area was discussed. And the annual hydrologic performance of bioretention systems was further analyzed under the optimized parameters. The study reveals that bioretention systems with underdrains and impervious boundaries do have some detention capability, while their total water retention capability is extremely limited. Better detention capability is noted for smaller rainfall events, deeper filter media, and design storms with a return period smaller than 2 years, and a cost-effective filter media depth is recommended in bioretention design. Better hydrologic effectiveness is achieved with a higher hydraulic conductivity and ratio of the bioretention surface area to the catchment area, and filter media whose conductivity is between the conductivity of loamy sand and sandy loam, and a surface area of 10% of the catchment area is recommended. In the long-term simulation, both infiltration volume and evapotranspiration are critical for the total rainfall treatment in bioretention systems.

Ecotoxicological effects on earthworms of fresh and aged nano-sized zero-valent iron (nZVI) in soil.

PubMed

El-Temsah, Yehia S; Joner, Erik J

2012-09-01

Although nano-sized zero-valent iron (nZVI) has been used for several years for remediation of contaminated soils and aquifers, only a limited number of studies have investigated secondary environmental effects and ecotoxicity of nZVI to soil organisms. In this study we therefore measured the ecotoxicological effects of nZVI coated with carboxymethyl cellulose on two species of earthworms, Eisenia fetida and Lumbricus rubellus, using standard OECD methods with sandy loam and artificial OECD soil. Earthworms were exposed to nZVI concentrations ranging from 0 to 2000 mg nZVI kg soil(-1) added freshly to soil or aged in non-saturated soil for 30 d prior to exposure. Regarding avoidance, weight changes and mortality, both earthworm species were significantly affected by nZVI concentrations ≥500 mg kg(-1)soil. Reproduction was affected also at 100 mg nZVI kg(-1). Toxicity effects of nZVI were reduced after aging with larger differences between soils compared to non-aged soils. We conclude that doses ≥500 mg nZVI kg(-1) are likely to give acute adverse effects on soil organisms, and that effects on reproduction may occur at significantly lower concentrations. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effect of soil moisture content on the splash phenomenon reproducibility.

PubMed

Ryżak, Magdalena; Bieganowski, Andrzej; Polakowski, Cezary

2015-01-01

One of the methods for testing splash (the first phase of water erosion) may be an analysis of photos taken using so-called high-speed cameras. The aim of this study was to determine the reproducibility of measurements using a single drop splash of simulated precipitation. The height from which the drops fell resulted in a splash of 1.5 m. Tests were carried out using two types of soil: Eutric Cambisol (loamy silt) and Orthic Luvisol (sandy loam); three initial pressure heads were applied equal to 16 kPa, 3.1 kPa, and 0.1 kPa. Images for one, five, and 10 drops were recorded at a rate of 2000 frames per second. It was found that (i) the dispersion of soil caused by the striking of the 1st drop was significantly different from the splash impact caused by subsequent drops; (ii) with every drop, the splash phenomenon proceeded more reproducibly, that is, the number of particles of soil and/or water that splashed were increasingly close to each other; (iii) the number of particles that were detached during the splash were strongly correlated with its surface area; and (iv) the higher the water film was on the surface the smaller the width of the crown was.

Effect of Soil Moisture Content on the Splash Phenomenon Reproducibility

PubMed Central

Ryżak, Magdalena; Bieganowski, Andrzej; Polakowski, Cezary

2015-01-01

One of the methods for testing splash (the first phase of water erosion) may be an analysis of photos taken using so-called high-speed cameras. The aim of this study was to determine the reproducibility of measurements using a single drop splash of simulated precipitation. The height from which the drops fell resulted in a splash of 1.5 m. Tests were carried out using two types of soil: Eutric Cambisol (loamy silt) and Orthic Luvisol (sandy loam); three initial pressure heads were applied equal to 16 kPa, 3.1 kPa, and 0.1 kPa. Images for one, five, and 10 drops were recorded at a rate of 2000 frames per second. It was found that (i) the dispersion of soil caused by the striking of the 1st drop was significantly different from the splash impact caused by subsequent drops; (ii) with every drop, the splash phenomenon proceeded more reproducibly, that is, the number of particles of soil and/or water that splashed were increasingly close to each other; (iii) the number of particles that were detached during the splash were strongly correlated with its surface area; and (iv) the higher the water film was on the surface the smaller the width of the crown was. PMID:25785859

Intrinsic vulnerability assessment of shallow aquifers of the sedimentary basin of southwestern Nigeria

PubMed Central

2018-01-01

The shallow groundwater of the multi-layered sedimentary basin aquifer of southwestern Nigeria was assessed based on its intrinsic vulnerability property. The vulnerability evaluation involves determining the protective cover and infiltration condition of the unsaturated zone in the basin. This was achieved using the PI (P stands for protective cover effectiveness of the overlying lithology and I indicates the degree of infiltration bypass) vulnerability method of the European vulnerability approach. The PI method specifically measures the protection cover and the degree to which the protective cover is bypassed. Intrinsic parameters assessed were the subsoil, lithology, topsoil, recharge and fracturing for the protective cover. The saturated hydraulic conductivity of topsoil, infiltration processes and the lateral surface and subsurface flow were evaluated for the infiltration bypassed. The results show moderate to very low vulnerability areas. Low vulnerability areas were characterised by lithology with massive sandstone and limestone, subsoils of sandy loam texture, high slopes and high depth to water table. The moderate vulnerability areas were characterised by high rainfall and high recharge, low water table, unconsolidated sandstones and alluvium lithology. The intrinsic vulnerability properties shown in vulnerability maps will be a useful tool in planning and monitoring land use activities that can be of impact in groundwater pollution.

Trichoderma harzianum enhances the production of nematicidal compounds in vitro and improves biocontrol of Meloidogyne javanica by Pseudomonas fluorescens in tomato.

PubMed

Siddiqui, I A; Shaukat, S S

2004-01-01

To determine the influence of soil-borne fungus Trichoderma harzianum on the biocontrol performance of Pseudomonas fluorescens strain CHA0 and its 2,4-diacetylphloroglucinol (DAPG) overproducing derivative CHA0/pME3424 against Meloidogyne javanica. Amendment of the culture filtrate (CF) or methanol extract of the CF of a T. harzianum strain Th6 to P. fluorescens growth medium enhanced the production of nematicidal compound(s) by bacterial inoculants in vitro. In addition, bacteria overwhelmingly expressed phl'-'lacZ reporter gene when the medium was amended with CF of T. harzianum. Pseudomonas fluorescens and T. harzianum applied together in unsterilized sandy loam soil caused greater reduction in nematode population densities in tomato roots. Trichoderma harzianum improves root-knot nematode biocontrol by the antagonistic rhizobacterium P. fluorescens both in vitro and under glasshouse conditions. The synergistic effect of T. harzianum on the production of nematicidal compound(s) critical in biocontrol may improve the efficacy of biocontrol bacteria against plant-parasitic nematodes. Considering the inconsistent performance of the biocontrol agents under field conditions, application of a mixture of compatible T. harzianum and P. fluorescens would more closely mimic the natural situation and might broaden the spectrum of biocontrol activity with enhanced efficacy and reliability of control.

Reduction of Root-Knot Nematode, Meloidogyne javanica, and Ozone Mass Transfer in Soil Treated with Ozone

PubMed Central

Qiu, Jinya Jack; Pryor, Alan

2009-01-01

Ozone gas (O3) is a reactive oxidizing agent with biocidal properties. Because of the current phasing out of methyl bromide, investigations on the use of ozone gas as a soil-fumigant were conducted. Ozone gas was produced at a concentration of 1% in air by a conventional electrical discharge O3 generator. Two O3 dosages and three gas flow rates were tested on a sandy loam soil collected from a tomato field that had a resident population of root knot nematodes, Meloidogyne javanica. At dosages equivalent to 50 and 250 kg of O3/ha, M. javanica were reduced by 24% and 68%, and free-living nematodes by 19% and 52%, respectively. The reduction for both M. javanica and free-living nematodes was dosage dependent and flow rate independent. The rates of O3 mass transfer (OMT) through three soils of different texture were greater at low and high moisture levels than at intermediate ones. At any one soil moisture level, the OMT rate varied with soil texture and soil organic matter content. Results suggest that soil texture, moisture, and organic matter content should be considered in determining O3 dosage needed for effective nematode control. PMID:22736821

Modelling Furrow Irrigation-Induced Erosion on a Sandy Loam Soil in Samaru, Northern Nigeria

PubMed Central

Dibal, Jibrin M.; Igbadun, H. E.; Ramalan, A. A.; Mudiare, O. J.

2014-01-01

Assessment of soil erosion and sediment yield in furrow irrigation is limited in Samaru-Zaria. Data was collected in 2009 and 2010 and was used to develop a dimensionless model for predicting furrow irrigation-induced erosion (FIIE) using the dimensional analyses approach considering stream size, furrow length, furrow width, soil infiltration rate, hydraulic shear stress, soil erodibility, and time flow of water in the furrows as the building components. One liter of water-sediment samples was collected from the furrows during irrigations from which sediment concentrations and soil erosion per furrow were calculated. Stream sizes Q (2.5, 1.5, and 0.5 l/s), furrow lengths X (90 and 45 m), and furrow widths W (0.75 and 0.9 m) constituted the experimental factors randomized in a split plot design with four replications. Water flow into and out of the furrows was measured using cutthroat flumes. The model produced reasonable predictions relative to field measurements with coefficient of determination R 2 in the neighborhood of 0.8, model prediction efficiency NSE (0.7000), high index of agreement (0.9408), and low coefficient of variability (0.4121). The model is most sensitive to water stream size. The variables in the model are easily measurable; this makes it better and easily adoptable. PMID:27471748

Energetic contaminants inhibit plant litter decomposition in soil.

PubMed

Kuperman, Roman G; Checkai, Ronald T; Simini, Michael; Sunahara, Geoffrey I; Hawari, Jalal

2018-05-30

Individual effects of nitrogen-based energetic materials (EMs) 2,4-dinitrotoluene (2,4-DNT), 2-amino-4,6-dinitrotoluene (2-ADNT), 4-amino-2,6-dinitrotoluene (4-ADNT), nitroglycerin (NG), and 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20) on litter decomposition, an essential biologically-mediated soil process, were assessed using Orchard grass (Dactylis glomerata) straw in Sassafras sandy loam (SSL) soil, which has physicochemical characteristics that support "very high" qualitative relative bioavailability for organic chemicals. Batches of SSL soil were separately amended with individual EMs or acetone carrier control. To quantify the decomposition rates, one straw cluster was harvested from a set of randomly selected replicate containers from within each treatment, after 1, 2, 3, 4, 6, and 8 months of exposure. Results showed that soil amended with 2,4-DNT or NG inhibited litter decomposition rates based on the median effective concentration (EC50) values of 1122 mg/kg and 860 mg/kg, respectively. Exposure to 2-ADNT, 4-ADNT or CL-20 amended soil did not significantly affect litter decomposition in SSL soil at ≥ 10,000 mg/kg. These ecotoxicological data will be helpful in identifying concentrations of EMs in soil that present an acceptable ecological risk for biologically-mediated soil processes. Published by Elsevier Inc.

[Survival capacity of Corynebacterium pseudotuberculosis biovar ovis in different soil types from Chubut, Argentine Patagonia].

PubMed

Alvarez, Laura; William, Aillin; Castro, Isabel; Valenzuela, Fernanda; Estevao Belchior, Silvia

Corynebacterium pseudotuberculosis is transmitted among sheep in Argentine Patagonia causing pseudotuberculosis. The bacterium penetrates the skin or mucous membrane wounds, infecting the superficial lymph nodes and viscera. When surface abscesses are cut during shearing, they drain their purulent contents and contaminate tools and the soil. The objective of this work was to evaluate the survival capacity of C. pseudotuberculosis over time, in soils from the extra-Andean Patagonia region. Five types of superficial soils were collected from different areas in Chubut province (extra-Andean Patagonia), having distinctive physicochemical properties including organic matter content (very high to nonexistent), pH (neutral to strongly alkaline), electrical conductivity (saline to non-saline) and texture (sandy, clayey, silty loam). Different aliquots of each type of soil were inoculated with C. pseudotuberculosis PAT10 strain isolated from a Patagonian sheep, and were stored at room temperature. The number of surviving bacteria was determined at various times. Sixty percent (60%) of the inoculated C. pseudotuberculosis population survived for 80 to 210 days in soils with moderate to high organic matter content respectively. Silty soils favored bacterial survival, whereas the variables pH and salinity had no effect on survival. Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Biodegradation of carbofuran and furathiocarb in soil: effect of pretreatment and microbial growth responses to carbofuran

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

Henry, K.M.

The rate of degradation of carbofuran was measured in Norfolk loamy sand and Lynchburg sandy loam soils with no known history of pesticide treatment. Degradation was measured by trapping /sup 14/CO/sub 2/ evolved from /sup 14/C-carbonyl carbofuran applied to soil in flasks. Loamy sand soil pretreated with 9 ..mu..g x g/sup -1/ carbofuran completely degraded a second or third application of 9 ..mu..g x g/sup -1/ within 1-3 days, but <5% was degraded in soil treated for the first time. Nitrogen, applied as 100 ..mu..g x g/sup -1/ in NH/sub 4/NO/sub 3/, very slightly increased the rate of degradation ofmore » 9 ..mu..g x g/sup -1/ carbofuran in the pretreated soils. The rate of degradation of carbofuran in the pretreated soils can be described by 1st order kinetics. However, in the soil pretreated with 9 ..mu..g x g/sup -1/ carbofuran, the rate of degradation of an 8 ng x g/sup -1/ treatment was biphasic, with only 65% rapidly degraded within 2 days. This /sup 14/CO/sub 2/ evolution curve was best described by a two-compartment model for the degradation of low levels of organics in soil.« less

Shifts in soil biodiversity-A forensic comparison between Sus scrofa domesticus and vegetation decomposition.

PubMed

Olakanye, Ayodeji O; Thompson, Tim; Ralebitso-Senior, T Komang

2015-12-01

In a forensic context, microbial-mediated cadaver decomposition and nutrient recycling cannot be overlooked. As a result, forensic ecogenomics research has intensified to gain a better understanding of cadaver/soil ecology interactions as a powerful potential tool for forensic practitioners. For this study, domestic pig (Sus scrofa domesticus) (4g) and grass (Agrostis/Festuca spp) cuttings (4g) were buried (July 2013 to July 2014) in sandy clay loam (80 g) triplicates in sealed microcosms (127 ml; 50 × 70 cm) with parallel soil only controls. The effects of the two carbon sources were determined by monitoring key environmental factors and changes in soil bacterial (16S rRNA gene) and fungal (18S rRNA gene) biodiversity. Soil pH changes showed statistically significant differences (p<0.05) between the treatments. The measured ecological diversity indices (Shannon-Wiener, HꞋ; Simpson, D; and richness, S) of the 16S rRNA and 18S rRNA gene profiles also revealed differences between the treatments, with bacterial and fungal community dominance recorded in the presence of S. scrofa domesticus and grass trimming decomposition, respectively. In contrast, no statistically significant difference in evenness (p>0.05) was observed between the treatments. Copyright © 2015 The Chartered Society of Forensic Sciences. Published by Elsevier Ireland 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.

Leaching behaviour of azoxystrobin and metabolites in soil columns.

PubMed

Ghosh, Rakesh Kumar; Singh, Neera

2009-09-01

Azoxystrobin [methyl (E)-2-{2-[6-(2-cyanophenoxy)pyrimidin-4-yloxy]phenyl}-3-methoxyacrylate], a strobilurin fungicide, is a broad-spectrum, systemic and soil-applied fungicide. Azoxystrobin has been registered for rice cultivation in India, but no information is available on its leaching behaviour in Indian soils. Therefore, leaching behaviour of azoxystrobin was studied in packed and intact soil columns under different irrigation regimes. Azoxystrobin did not leach out of the 300 mm long columns after 126 and 362 mm rainfall. After percolating water equivalent to 362 mm rainfall, azoxystrobin leached down to 10-15 cm (packed columns) and 15-20 cm (intact columns) depth. Azoxystrobin was not detected in the leachate from the packed column leached with 94.5 mL water every week (140 mm rainfall per month) during the 28 weeks of the study period. However, azoxystrobin acid, formed by azoxystrobin degradation, was detected in the leachate after 18 weeks. At the end of the study, azoxystrobin had leached down to 5-10 cm depth, and only 60% of initially applied azoxystrobin was recovered from the soil. The results indicate that azoxystrobin is fairly immobile in sandy loam soil, but azoxystrobin acid, a major metabolite of azoxystrobin, is quite mobile and may pose a threat of soil and groundwater contamination. Copyright 2009 Society of Chemical Industry.

2,4-Dichlorophenoxyacetic acid (2,4-D) sorption and degradation dynamics in three agricultural soils.

PubMed

Boivin, Arnaud; Amellal, Samira; Schiavon, Michel; van Genuchten, Martinus Th

2005-11-01

The fate and transport of 2,4-dichlorophenoxyacetic acid (2,4-D) in the subsurface is affected by a complex, time-dependent interplay between sorption and mineralization processes. 2,4-D is biodegradable in soils, while adsorption/desorption is influenced by both soil organic matter content and soil pH. In order to assess the dynamic interactions between sorption and mineralization, 2,4-D mineralization experiments were carried using three different soils (clay, loam and sand) assuming different contact times. Mineralization appeared to be the main process limiting 2,4-D availability, with each soil containing its own 2,4-D decomposers. For the clay and the loamy soils, 45 and 48% of the applied dose were mineralized after 10 days. By comparison, mineralization in the sandy soil proceeded initially much slower because of longer lag times. While 2,4-D residues immediately after application were readily available (>93% was extractable), the herbicide was present in a mostly unavailable state (<2% extractable) in all three soils after incubation for 60 days. We found that the total amount of bound residue decreased between 30 and 60 incubation days. Bioaccumulation may have led to reversible immobilization, with some residues later becoming more readily available again to extraction and/or mineralization.

Quality of white cabbage yield and potential risk of ground water nitrogen pollution, as affected by nitrogen fertilisation and irrigation practices.

PubMed

Maršić, Nina Kacjan; Sturm, Martina; Zupanc, Vesna; Lojen, Sonja; Pintar, Marina

2012-01-15

The effect of different fertilisation (broadcast solid NPK application and fertigation with water-soluble fertiliser) and irrigation practices (sprinkler and drip irrigation) on yield, the nitrate content in cabbage (Brassica oleracea var. capitata L.) and the cabbage N uptake was detected, in order to assess the potential risk for N losses, by cultivation on sandy-loam soil. The N rate applied on the plots was 200 kg N ha(-1). The highest yield (93 t ha(-1)) and nitrate content (1256 mg kg(-1) DW) were found with treatments using broadcast fertilisation and sprinkler irrigation. On those plots the negative N balance (-30 kg N ha(-1)) was recorded, which comes mainly from the highest crop N uptake (234 kg N ha(-1)) indicating the lowest potential for N losses. In terms of yield quality and the potential risk for N losses, broadcast fertilisation combined with sprinkler irrigation proved to be the most effective combination among the tested practices under the given experimental conditions. The importance of adequate irrigation is also evident, namely in plots on which 50% drip irrigation was applied, the lowest yield was detected and according to the positive N balance, a higher potential for N losses is expected. Copyright © 2011 Society of Chemical Industry.

Accumulation of organic C components in soil and aggregates

PubMed Central

Yu, Hongyan; Ding, Weixin; Chen, Zengming; Zhang, Huanjun; Luo, Jiafa; Bolan, Nanthi

2015-01-01

To explore soil organic carbon (SOC) accumulation mechanisms, the dynamics of C functional groups and macroaggregation were studied synchronously through aggregate fractionation and 13C NMR spectroscopy in sandy loam soil following an 18-year application of compost and fertilizer in China. Compared with no fertilizer control, both compost and fertilizer improved SOC content, while the application of compost increased macroaggregation. Fertilizer application mainly increased the levels of recalcitrant organic C components characterized by methoxyl/N-alkyl C and alkyl C, whereas compost application mainly promoted the accumulation of methoxyl/N-alkyl C, phenolic C, carboxyl C, O-alkyl C and di-O-alkyl C in bulk soil. The preferential accumulation of organic C functional groups in aggregates depended on aggregate size rather than nutrient amendments. These groups were characterized by phenolic C and di-O-alkyl C in the silt + clay fraction, carboxyl C in microaggregates and phenolic C, carboxyl C and methoxyl/N-alkyl C in macroaggregates. Thus, the differences in accumulated organic C components in compost- and fertilizer-amended soils were primarily attributable to macroaggregation. The accumulation of methoxyl/N-alkyl C in microaggregates effectively promoted macroaggregation. Our results suggest that organic amendment rich in methoxyl/N-alkyl C effectively improved SOC content and accelerated macroaggregation in the test soil. PMID:26358660

[Hydrological characteristics of calcareous soil with contrasting architecture on dolomite slope of Northwest Guangxi].

PubMed

Zhang, Xing; Wang, Ke Lin; Fu, Zhi Yong; Chen, Hong Song; Zhang, Wei; Shi, Zhi Hua

2017-07-18

The traditional hydrology method, stable hydrogen and oxygen isotope technology, and rainfall simulation method were combined to investigate the hydrological function of small experimental plots (2 m×1.2 m) of contrasting architecture in Northwest Guangxi dolomite area. There were four typical catenary soils along the dolomite peak-cluster slope, which were the whole-sand, up-loam and down-sand, the whole loam, up-clay and down-sand soil types, respectively. All the experimental plots generated little amounts of overland runoff and had a high surface infiltration rate, ranging from 41 to 48 mm·h -1 , and the interflow and deep percolation were the dominant hydrological progress. The interflow was classified into interflow in soil clay A and C according to soil genetic layers. For interflow in soil clay A, matrix flow was generated from the whole-sand, up-loam and down-sand, up-clay and down-sand soil types, but preferential flow dominated in the whole-loam soil type. As for interflow in soil clay C, preferential flow dominated in the whole-loam, up-clay and down-sand, up-loam and down-sand soil types. The soils were shallow yet continuously distributed along the dolomite slope. The difference of hydrological characteristics in soil types with different architectures mainly existed in the runoff generation progress of each interface underground. It proved that the a 3-D perspective was needed to study the soil hydrological functions on dolomite slope of Northwest Guangxi, and a new way paying more attention on underground hydrological progress should be explored to fully reveal the near-surface hydrological processes on karst slope.

Bromoxynil Degradation in a Mississippi Silt Loam Soil

USDA-ARS?s Scientific Manuscript database

There is a paucity of data on bromoxynil fate in agricultural soils. The objective of these laboratory experiments were to 1) assess bromoxynil sorption, mineralization, bound residue formation, and persistence of extractable residues in native (i.e., non-autoclaved) Dundee silt loam soil collecte...

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

NASA Astrophysics Data System (ADS)

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

2009-04-01

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

Erodibility from natural rainfall events on soils of the Pacific Northwest

USDA-ARS?s Scientific Manuscript database

Erosion event data from long-term USLE-size continuous fallow plots (Palouse silt loam) at the Palouse Conservation Field Station (PCFS) at Pullman, WA and similar plots (Thatuna silt loam) near the Columbia Plateau Conservation Research Center (CPCRC) at Pendleton, OR provided an opportunity to cal...

Mitigation of Liquefaction in Sandy Soils Using Stone Columns

NASA Astrophysics Data System (ADS)

Selcuk, Levent; Kayabalı, Kamil

2010-05-01

Soil liquefaction is one of the leading causes of earthquake-induced damage to structures. Soil improvement methods provide effective solutions to reduce the risk of soil liquefaction. Thus, soil ground treatments are applied using various techniques. However, except for a few ground treatment methods, they generally require a high cost and a lot of time. Especially in order to prevent the risk of soil liquefaction, stone columns conctructed by vibro-systems (vibro-compaction, vibro-replacement) are one of the traditional geotechnical methods. The construction of stone columns not only enhances the ability of clean sand to drain excess pore water during an earthquake, but also increases the relative density of the soil. Thus, this application prevents the development of the excess pore water pressure in sand during earthquakes and keeps the pore pressure ratio below a certain value. This paper presents the stone column methods used against soil liquefaction in detail. At this stage, (a) the performances of the stone columns were investigated in different spacing and diameters of columns during past earthquakes, (b) recent studies about design and field applications of stone columns were presented, and (c) a new design method considering the relative density of soil and the capacity of drenage of columns were explained in sandy soil. Furthermore, with this new method, earthquake performances of the stone columns constructed at different areas were investigated before the 1989 Loma Prieta and the 1994 Northbridge earthquakes, as case histories of field applications, and design charts were compiled for suitable spacing and diameters of stone columns with consideration to the different sandy soil parameters and earhquake conditions. Key Words: Soil improvement, stone column, excess pore water pressure

Comparing gibbs energy relationships for ammonia volatilizations from agricultural soils for potato production

USDA-ARS?s Scientific Manuscript database

Soil drought, that can be enhanced by global warming increases ammonia (NH3) volatilization. This laboratory study was conducted with two soils: Krome Gravelly Loam (KGL) from Florida and Warden Silt Loam (WSL) from Washington State and two fertilizers: Ammonium sulfate [(NH4)2SO4] or ammonium nitra...

Early Diagenesis of Subseafloor Sandy Sediments Closely Related to Gas Hydrate Occurrences and Their Provenances in the Eastern Margin of Japan Sea

NASA Astrophysics Data System (ADS)

Uchida, T.; Sakai, H.; Horiuchi, S.; Matsumoto, R.

2015-12-01

A lot of effort have been put into recovering gas hydrate, methane induced carbonate, and associated sediments in order to develop the geologic model of gas hydrate accumulation and evaluate its possible environmental impact for the last glacial-interglacial cycles. Having investigated gas hydrate occurrences in the eastern margin of Japan Sea revealed wide distributions of chimney-shape gas hydrate concentrations beneath the seafloor, confirmed off Shimane and off Akita/Yamagata as well as off Joetsu (Niigata), which are quite different from the occurrences of pore space hydrate filling intergranular pore systems of sands recognized in Nankai Trough, Mallik and other sites. Many sediment samples have been obtained below from the Umitaka Spur, Joetsu Channel, Toyama Trough, Mogami Trough and Okushiri Ridge areas. Small amounts of sandy sediment have been retrieved as thin intercalations in Holocene and Pleistocene silty/muddy layers, where trace fossils and strong bioturbations are commonly observed. Sandy sediments consist of very fine- to fine-grained sand grains, and are sometimes tuffaceous. Pore-size distribution measurements and thin-section observations of these sands were carried out, which indicate that porosities of silty sediments are around 50 % but those of arenites range from 42 to 52 %, of which mean pore sizes and permeabilities are larger than those of silty sediments. These coarser sediments might have been transported approximately around 3 to 30 ka due to the tephra ages, where supplying sediments might be abundant due to sea level fluctuation during the Pleistocene ice age. Sandy sediments contain not only detrital quartz and feldspar but mafic minerals (pyroxene, amphibole and mica), contents of which may indicate their provenances. Silty/muddy sediments usually contain diatom tests, foraminifers and framboidal pyrites, and, in particular, the shapes of diatom are usually various, dominantly fragmental and infrequently preserved. It is remarked that physical diagenesis proceeds first due to mechanical compaction, whereas chemical diagenesis advances very slowly in early diagenesis. This study was performed as a part of the MH21 Research Consortium on methane hydrate in Japan and the METI project entitled "FY2014 promoting research and development on methane hydrate."

Forest Species Compared in Ozark Plantations

Treesearch

William R. Maple

1965-01-01

Fifteen years ago a series of plantations containing native and nonnative forest tree species was established on the Henry R. Koen Experimental Forest in Newton County. The sites, which were representative of abandoned fields in the Arkansas portion of the Ozark Mountains, included loamy sand, silty clay loam, and cherty silt loam soils. All had similar histories of...

Responses of Young Slash Pine on Poorly Drained to Somewhat Poorly Drained Silt Loam Soils to Site Preparation and Fertilization Treatments

Treesearch

James D. Haywood

1995-01-01

Slash pines (Pinus elliottii Engelm. var. elliottii) were planted on poorly drained Wrightsville and somewhat poorly drained Vidrine silt loam soils in southwest Louisiana. Neither flat disking nor bedding increased pine growth and yield substantially after nine growing seasons, but broadcast application of triple superphoshate...

Forms and Lability of Phosphorus in Humic Acid Fractions of Hord Silt Loam Soil

USDA-ARS?s Scientific Manuscript database

Phosphorus (P) has long been known to be present in soil humic fractions, but little is known about specific P forms in humic fractions, or their lability. We extracted the mobile humic acid (MHA) and recalcitrant calcium humate (CaHA) fractions from a Nebraska Hord silt loam soil under continuous c...

Planted Pines do not Respond to Bedding on an Acadia-Beauregard-Kolin Silt Loam Site

Treesearch

James D. Haywood

1980-01-01

Average height and volume of loblolly and slash pines were not affected by site treatment or soil differences 15 years after planting on an Acadia-Beauregard-Kolin silt loam site. Slash pine averaged 2.04 m more in height and yielded 22 percent more volume per hectare than did loblolly pine.

Phosphorus forms in Alabama decatur silt loam with upland cotton production

USDA-ARS?s Scientific Manuscript database

Alabama was historically known as "The Cotton State." It ranks 4th with 10.1% of U.S. cotton production. We assessed the forms and labile P in the Alabama Decatur silt loam cotton soils, and evaluated the impact of management practices on the soil P forms. We observed that manure and inorganic ferti...

A Novel Method for Measurement and Characterization of Soil Macroporosity

Treesearch

Christopher Barton; Tasos Karathanasis

2002-01-01

Quantitative macropore characterizations were performed in large zero-tension soil lysimeters of a Maury silt loam (fine, mixed, mesic Typic Paleudalf) and a Loradale silt loam (fine, silty, mixed, mesic Typic Axgiudoll) soil in an effort to assess potential colloid transport. Steel pipe sections (50 cm diameter X 100 cm length) were hydraulically driven into the soil...

Soil microbial community response to surfactants and herbicides in two soils

USDA-ARS?s Scientific Manuscript database

The impact of herbicides on more than just the target weed and the effect of some herbicides on the soil biota is of environmental interest. The surfactants that are often used with herbicides are also coming under fire as a potential harm to the soil life. We used a silt loam and a silty clay loam ...

Vadose Zone Nitrate Transport Dynamics Resulting from Agricultural Groundwater Banking

NASA Astrophysics Data System (ADS)

Murphy, N. P.; McLaughlin, S.; Dahlke, H. E.

2017-12-01

In recent years, California's increased reliance on groundwater resources to meet agricultural and municipal demands has resulted in significant overdraft and water quality issues. Agricultural groundwater banking (AGB) has emerged as a promising groundwater replenishment opportunity in California; AGB is a form of managed aquifer recharge where farmland is flooded during the winter using excess surface water in order to recharge the underlying groundwater. Suitable farmland that is connected to water delivery systems is available for AGB throughout the Central Valley. However, questions remain how AGB could be implemented on fertilized agricultural fields such that nitrate leaching from the root zone is minimized. Here, we present results from field and soil column studies that investigate the transport dynamics of nitrogen in the root and deeper vadose zone during flooding events. We are specifically interested in estimating how timing and duration of flooding events affect percolation rates, leaching and nitrification/denitrification processes in three soil types within the Central Valley. Laboratory and field measurements include nitrogen (NO3-, NH4+, NO2-, N2O), redox potentials, total organic carbon, dissolved oxygen, moisture content and EC. Soil cores are collected in the field before and after recharge events up to a depth of 4m, while other sensors monitor field conditions continuously. Preliminary results from the three field sites show that significant portions of the applied floodwater (12-62 cm) infiltrated below the root zone: 96.1% (Delhi), 88.6% (Modesto) and 76.8% (Orland). Analysis of the soil cores indicate that 70% of the residual nitrate was flushed from the sandy soil, while the fine sandy loam showed only a 5% loss and in some cores even an increase in soil nitrate (in the upper 20cm). Column experiments support these trends and indicate that increases in soil nitrate in the upper root zone might be due to organic nitrogen mineralization and nitrification, facilitated by the added water. The next step will be to use field and laboratory data for the parameterization of the HP1 (Coupled Hydrus-1D and PHREEQC) model to develop an understanding of nitrogen transport in differing soil textures, and develop best management practices for future AGB projects.

Evaluating drywells for stormwater management and enhanced aquifer recharge

NASA Astrophysics Data System (ADS)

Sasidharan, Salini; Bradford, Scott A.; Šimůnek, Jiří; DeJong, Bill; Kraemer, Stephen R.

2018-06-01

Drywells are increasingly used for stormwater management and enhanced aquifer recharge, but only limited research has quantitatively determined the performance of drywells. Numerical and field scale experiments were, therefore, conducted to improve our understanding and ability to characterize the drywell behavior. In particular, HYDRUS (2D/3D) was modified to simulate transient head boundary conditions for the complex geometry of the Maxwell Type IV drywell; i.e., a sediment chamber, an overflow pipe, and the variable geometry and storage of the drywell system with depth. Falling-head infiltration experiments were conducted on drywells located at the National Training Center in Fort Irwin, California (CA) and a commercial complex in Torrance, CA to determine in situ soil hydraulic properties (the saturated hydraulic conductivity, Ks, and the retention curve shape parameter, α) for an equivalent uniform soil profile by inverse parameter optimization. A good agreement between the observed and simulated water heights in wells was obtained for both sites as indicated by the coefficient of determination 0.95-0.99-%, unique parameter fits, and small standard errors. Fort Irwin and Torrance drywells had very distinctive soil hydraulic characteristics. The fitted value of Ks=1.01 × 10-3 m min-1 at the Torrance drywell was consistent with the sandy soil texture at this site and the default value for sand in the HYDRUS soil catalog. The drywell with this Ks= 1.01 × 10-3 m min-1 could easily infiltrate predicted surface runoff from a design rain event (∼51.3 m3) within 5760 min (4 d). In contrast, the fitted value of Ks=2.25 × 10-6 m min-1 at Fort Irwin was very low compared to the Torrance drywell and more than an order of magnitude smaller than the default value reported in the HYDRUS soil catalog for sandy clay loam at this site, likely due to clogging. These experiments and simulations provide useful information to characterize effective soil hydraulic properties in situ, and to improve the design of drywells for enhanced recharge.

The effect of vegetation and soil texture on the nature of organics in runoff from a catchment supplying water for domestic consumption.

PubMed

Awad, John; van Leeuwen, John; Abate, Dawit; Pichler, Markus; Bestland, Erick; Chittleborough, David J; Fleming, Nigel; Cohen, Jonathan; Liffner, Joel; Drikas, Mary

2015-10-01

The influence of vegetation and soil texture on the concentration and character of dissolved organic matter (DOM) present in runoff from the surface and sub-surface of zero order catchments of the Myponga Reservoir-catchment (South Australia) was investigated to determine the impacts of catchment characteristics and land management practices on the quality of waters used for domestic supply. Catchments selected have distinct vegetative cover (grass, native vegetation or pine) and contrasting texture of the surface soil horizon (sand or clay loam/clay). Water samples were collected from three slope positions (upper, middle, and lower) at soil depths of ~30 cm and ~60 cm in addition to overland flows. Filtered (0.45 μm) water samples were analyzed for dissolved organic carbon (DOC) and UV-visible absorbance and by F-EEM and HPSEC with UV and fluorescence detection to characterize the DOM. Surface and sub-surface runoff from catchments with clay soils and native vegetation or grass had lower DOC concentrations and lower relative abundances of aromatic, humic-like and high molecular weight organics than runoff from sandy soils with these vegetative types. Sub-surface flows from two catchments with Pinus radiata had similar DOC concentrations and DOM character, regardless of marked variation in surface soil texture. Runoff from catchments under native vegetation and grass on clay soils resulted in lower DOC concentrations and hence would be expected to have lower coagulant demand in conventional treatment for potable water supply than runoff from corresponding sandy soil catchments. However, organics in runoff from clay catchments would be more difficult to remove by coagulation. Surface waters from the native vegetation and grass catchments were generally found to have higher relative abundance of organic compounds amenable to removal by coagulation compared with sub-surface waters. Biophysical and land management practices combine to have a marked influence on the quality of source water used for domestic supply. Copyright © 2015 Elsevier B.V. All rights reserved.

Study of Usage Areas of Clay Samples of Asphaltite Quarries in Sirnak, Turkey

NASA Astrophysics Data System (ADS)

Bilgin, Oyku

2017-12-01

The asphaltite of Sirnak, Turkey are in the form of 12 veins and their total reserves are anticipated to be approximately 200 million tons in a field of 25.000 hectares. The asphaltites at the Sirnak region are in the form of fault and crack fillings and take place together with clay minerals at their side rock. The main raw materials used in the production of cement are limestone, clay and marn known as sedimentary rocks. Limestone for CaO and clay minerals for SiO2, Al2O3, and Fe2O3, which are the main compounds of clinker production, are the main raw materials. Other materials containing these four oxides like marn are also used as cement raw material. Conformity levels of the raw materials to be used in cement production vary according to their chemical compounds. The rocks to be used as clay mineral are evaluated by taking the rate of silicate and alumina into consideration. The soils suitable for brick-tile productions are named as sandy clay. Their difference from the ceramic clays is that they are richer in terms of iron, silica and carbonate. These soils are also known under the names such as clay, arid, alluvium, silt, loam and argil. Inside these soils, minerals such as quartz, montmorillonite, kaolinite, calcite, limonite, hidromika, sericite, illite, and chlorite are available. Some parts of the soils consist of clays in amorphous structure. Limestone parts, gypsums, organic substances and bulky rock residuals spoil the quality. The soils suitable for brick production may not be suitable for tile production. In this case, their sandy soils should be mixed up with the clays with fine granule structure which is high in plasticity. During asphaltite mining in Sirnak region, clays forming side rock are gathered at dump sites. In this study; SQX analyses of the clay samples taken from Avgamasya, Seridahli and Segürük asphaltite veins run in Sirnak region are carried out and their usage areas are searched.

Combined Application of Biofertilizers and Inorganic Nutrients Improves Sweet Potato Yields

PubMed Central

Mukhongo, Ruth W.; Tumuhairwe, John B.; Ebanyat, Peter; AbdelGadir, AbdelAziz H.; Thuita, Moses; Masso, Cargele

2017-01-01

Sweet potato [Ipomoea batatas (L) Lam] yields currently stand at 4.5 t ha−1 on smallholder farms in Uganda, despite the attainable yield (45–48 t ha−1) of NASPOT 11 cultivar comparable to the potential yield (45 t ha−1) in sub-Saharan Africa (SSA). On-farm field experiments were conducted for two seasons in the Mt Elgon High Farmlands and Lake Victoria Crescent agro-ecological zones in Uganda to determine the potential of biofertilizers, specifically arbuscular mycorrhizal fungi (AMF), to increase sweet potato yields (NASPOT 11 cultivar). Two kinds of biofertilizers were compared to different rates of phosphorus (P) fertilizer when applied with or without nitrogen (N) and potassium (K). The sweet potato response to treatments was variable across sites (soil types) and seasons, and significant tuber yield increase (p < 0.05) was promoted by biofertilizer and NPK treatments during the short-rain season in the Ferralsol. Tuber yields ranged from 12.8 to 20.1 t ha−1 in the Rhodic Nitisol (sandy-clay) compared to 7.6 to 14.9 t ha−1 in the Ferralsol (sandy-loam) during the same season. Root colonization was greater in the short-rain season compared to the long-rain season. Biofertilizers combined with N and K realized higher biomass and tuber yield than biofertilizers alone during the short-rain season indicating the need for starter nutrients for hyphal growth and root colonization of AMF. In this study, N0.25PK (34.6 t ha−1) and N0.5PK (32.9 t ha−1) resulted in the highest yield during the long and the short-rain season, respectively, but there was still a yield gap of 11.9 and 13.6 t ha−1 for the cultivar. Therefore, a combination of 90 kg N ha−1 and 100 kg K ha−1 with either 15 or 30 kg P ha−1 can increase sweet potato yield from 4.5 to >30 t ha−1. The results also show that to realize significance of AMF in nutrient depleted soils, starter nutrients should be included. PMID:28348569

In-situ degradation of soil-sorbed 17β-estradiol using carboxymethyl cellulose stabilized manganese oxide nanoparticles: Column studies.

PubMed

Han, Bing; Zhang, Man; Zhao, Dongye

2017-04-01

This work tested a new remediation technology for in-situ degradation of estrogens by delivering a new class of stabilized manganese oxide (MnO 2 ) nanoparticles in contaminated soils. The nanoparticles were prepared using a food-grade carboxymethyl cellulose (CMC) as a stabilizer, which was able to facilitate particle delivery into soil. The effectiveness of the technology was tested using 17β-estradiol (E2) as a model estrogen and three sandy loams (SL1, SL2, and SL3) as model soils. Column transport tests showed that the nanoparticles can be delivered in the three soils, though retention of the nanoparticles varied. The nanoparticle retention is strongly dependent on the injection pore velocity. The treatment effectiveness is highly dependent upon the mass transfer rates of both the nanoparticles and contaminants. When the E2-laden soils were treated with 22-130 pore volumes of a 0.174 g/L MnO 2 nanoparticle suspension, up to 88% of water leachable E2 was degraded. The nanoparticles were more effective for soils that offer moderate desorption rates of E2. Decreasing injection velocity or increasing MnO 2 concentration facilitate E2 degradation. The nanoparticles-based technology appears promising for in-situ oxidation of endocrine disruptors in groundwater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nature's amazing biopolymer: basic mechanical and hydrological properties of soil affected by plant exudates

NASA Astrophysics Data System (ADS)

Naveed, Muhammad; Roose, Tiina; Raffan, Annette; George, Timothy; Bengough, Glyn; Brown, Lawrie; Keyes, Sam; Daly, Keith; Hallett, Paul

2016-04-01

Plant exudates are known to have a very large impact on soil physical properties through changes in mechanical and hydrological processes driven by long-chain polysaccharides and surface active compounds. Whilst these impacts are well known, the basic physical properties of these exudates have only been reported in a small number of studies. We present data for exudates obtained from barley roots and chia seeds, incorporating treatments examining biological decomposition of the exudates. When these exudates were added to a sandy loam soil, contact angle and drop penetration time increased exponentially with increasing exudate concentration. These wetting properties were strongly correlated with both exudate density and zero-shear viscosity, but not with exudate surface tension. Water holding capacity and water repellency of exudate mixed soil tremendously increased with exudate concentration, however they were significantly reduced on decomposition when measured after 14 days of incubation at 16C. Mechanical stability greatly increased with increasing exudate amendment to soils, which was assessed using a rheological amplitude sweep test near saturation, at -50 cm matric potential (field capacity) using indentation test, and at air-dry condition using the Brazilian test. This reflects that exudates not only attenuate plant water stress but also impart mechanical stability to the rhizosphere. These data are highly relevant to the understanding and modelling of rhizosphere development, which is the next phase of our research.

Water flux through a semi-deciduous forest grove of the Orinoco savannas.

PubMed

San José, José J; Montes, Ruben A; Florentino, Adriana

1995-02-01

Water relations were analysed in a semi-deciduous forest grove occurring in the oxisols of the Orinoco savannas. This grove has a shallow unconsolidated ironstone cuirass, which is overlaid by a sandy loam layer (0.0-0.5 m) that contains more than 90% of the grove forest root phytomass. Evapotranspiration and through drainage were calculated by using data from the soil profile as related to physical characteristics of the site root zone, hydraulic conductivity, volumetric water content and potential hydraulic gradient. Mean annual evapotranspiration was 783 mm year -1 and annual through drainage below the root zone was 14% (162 mm year -1 ) of the gross rainfall. This drainage recharged the 42% of the annual saturation deficit of the water table. Similar mean annual evapotranspiration (770 mm year -1 ) was also calculated by using the water balance components. The mean daily coupling omega factor (Ω) between the grove canopy and the surrounding atmosphere indicated that a high degree of coupling (Ω=0.14±0.16) occurs in the grove and evapotranspiration was mainly controlled by surface conductance. As the dry season proceeded, the soil saturation deficit (δθ) increased rapidly resulting in a threshold surface conductance (0.030-0.005 m s -1 ) for δθ ranging from 0.05 to 0.10. Hypotheses to explain the omnipresence of perennial species in the wide range of physical conditions in neotropical savannas are discussed.

Role of EDTA in arsenic mobilization and its uptake by maize grown on an As-polluted soil.

PubMed

Abbas, Mohamed H H; Abdelhafez, Ahmed A

2013-01-01

EDTA amendments are widely used for micronutrient fertilization in arid soils, besides their effectiveness in the remediation process of heavy metal from contaminated soils. However, the persistence of EDTA in arsenic contaminated soil may have further negative effects on the grown plants. To investigate the influences of EDTA on soil As, a pot experiment was conducted using a sandy clay loam As-polluted soil treated with gradual rates of EDTA (0, 1.0, 2.5 and 5 mmol kg(-1)) and planted with maize for two months. The key findings reveal that EDTA applications increased AB-DTPA extractable and water soluble As significantly. Such increases seemed to be the main reasons behind the increase in As uptake by maize plants as the addition of EDTA at the rates of 1.0, 2.5 and 5.0 mmol kg(-1) increased significantly As uptake by shoots 1.5, 2.4 and 3.0 folds, respectively compared to the untreated soil. On the other hand, As uptake by roots did not increase significantly except with the highest application rates of 2.5 and 5.0 mmol kg(-1). The results also show that arsenic translocation factor (TF) values were too low to attain successful phytoextraction. In conclusion, the bioavailable fraction of As is important to investigate the phytoextraction and phytotoxicity of As. Copyright © 2012 Elsevier Ltd. All rights reserved.

High-resolution synchrotron imaging shows that root hairs influence rhizosphere soil structure formation.

PubMed

Koebernick, Nicolai; Daly, Keith R; Keyes, Samuel D; George, Timothy S; Brown, Lawrie K; Raffan, Annette; Cooper, Laura J; Naveed, Muhammad; Bengough, Anthony G; Sinclair, Ian; Hallett, Paul D; Roose, Tiina

2017-10-01

In this paper, we provide direct evidence of the importance of root hairs on pore structure development at the root-soil interface during the early stage of crop establishment. This was achieved by use of high-resolution (c. 5 μm) synchrotron radiation computed tomography (SRCT) to visualise both the structure of root hairs and the soil pore structure in plant-soil microcosms. Two contrasting genotypes of barley (Hordeum vulgare), with and without root hairs, were grown for 8 d in microcosms packed with sandy loam soil at 1.2 g cm -3 dry bulk density. Root hairs were visualised within air-filled pore spaces, but not in the fine-textured soil regions. We found that the genotype with root hairs significantly altered the porosity and connectivity of the detectable pore space (> 5 μm) in the rhizosphere, as compared with the no-hair mutants. Both genotypes showed decreasing pore space between 0.8 and 0.1 mm from the root surface. Interestingly the root-hair-bearing genotype had a significantly greater soil pore volume-fraction at the root-soil interface. Effects of pore structure on diffusion and permeability were estimated to be functionally insignificant under saturated conditions when simulated using image-based modelling. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Conservation tillage, optimal water and organic nutrient supply enhance soil microbial activities during wheat (Triticum Aestivum L.) cultivation

PubMed Central

Sharma, Pankaj; Singh, Geeta; Singh, Rana P.

2011-01-01

The field experiments were conducted on sandy loam soil at New Delhi, during 2007 and 2008 to investigate the effect of conservation tillage, irrigation regimes (sub-optimal, optimal and supra-optimal water regimes), and integrated nutrient management (INM) practices on soil biological parameters in wheat cultivation. The conservation tillage soils has shown significant (p<0.05) increase in soil respiration (81.1%), soil microbial biomass carbon (SMBC) (104%) and soil dehydrogenase (DH) (59.2%) compared to the conventional tillage soil. Optimum water supply (3-irrigations) enhanced soil respiration over sub-optimum and supra-optimum irrigations by 13.32% and 79% respectively. Soil dehydrogenase (DH) activity in optimum water regime has also increased by 23.33% and 8.18% respectively over the other two irrigation regimes. Similarly, SMBC has also increased by 12.14% and 27.17% respectively in soil with optimum water supply compared to that of sub-optimum and supra-optimum water regime fields. The maximum increase in soil microbial activities is found when sole organic source (50% Farm Yard Manure+25% biofertilizer+25% Green Manure) has been used in combination with the conservation tillage and the optimum water supply. Study demonstrated that microbial activity could be regulated by tillage, water and nitrogen management in the soil in a sustainable manner. PMID:24031665

Suppression of nitrification and N2O emission by karanjin--a nitrification inhibitor prepared from karanja (Pongamia glabra Vent.).

PubMed

Majumdar, Deepanjan

2002-06-01

A laboratory incubation study was undertaken to study nitirification and N2O emission in an alluvial, sandy loam soil (typic ustochrept), fertilized with urea and urea combined with different levels of two nitrification inhibitors viz. karanjin and dicyandiamide (DCD). Karanjin [a furanoflavonoid, obtained from karanja (Pongamia glabra Vent.) seeds] and DCD were incorporated at the rate of 5%, 10%, 15%, 20% and 25% of applied urea-N (100 mg kg(-1) soil), to the soil (100 g) adjusted to field capacity moisture content. Mean N2O flux was appreciably reduced on addition of the inhibitors with urea. Amounts of nitrified N (i.e. (NO3- + NO2-)-N) in total inorganic N (i.e. (NO3 + NO2- + NH4+)-N) in soil were found to be much lower on the addition of karanjin with urea (2-8%) as compared to urea plus DCD (14-66%) during incubation, indicating that karanjin was much more potent nitrification inhibitor than DCD. Nitrification inhibition was appreciable on the application of different levels of karanjin (62-75%) and DCD (9-42%). Cumulative N2O-N loss was found to be in the range of 0.5-80% of the nitrified N at different stages of incubation. Application of karanjin resulted in higher mitigation of total N2O-N emission (92-96%) when compared with DCD (60-71%).

Impact of sediment particle size on biotransformation of 17β-estradiol and 17β-trenbolone.

PubMed

Zhang, Yun; Sangster, Jodi L; Gauza, Lukasz; Bartelt-Hunt, Shannon L

2016-12-01

Soil/sediment particle size has been reported to influence the sorption and bioavailability of steroid hormones in the environment. However, the impact of particle size on biotransformation has not been well elucidated. The present study investigated the dissipation of 17β-estradiol and 17β-trenbolone and the formation and degradation of the subsequent transformation products in different size fractions of a sandy and a silt loam sediment. The results showed that the decay of 17β-estradiol and 17β-trenbolone associated with fine particles followed a biphasic pattern with more rapid decay in the initial phase followed by a second phase with slower decay of the residues compared to their decay rates in the sand fraction. Estrone and trendione were detected as a primary biotransformation product for 17β-estradiol and 17β-trenbolone, respectively. The parent-to-product conversion ratios and the degradation rates of estrone and trendione varied among different size fractions, but no consistent correlation was observed between decay rates and sediment particle size. Estrone and trendione decayed in the whole sediments at rates not statistically different from those associated with the fine fractions. These results indicate that fine particles may play an important role in influencing the persistence of and the potential risk posed by steroid hormones in the aquatic systems. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparison of pore water samplers and cryogenic distillation under laboratory and field conditions for soil water stable isotope analysis.

PubMed

Thoma, Michael; Frentress, Jay; Tagliavini, Massimo; Scandellari, Francesca

2018-02-15

We used pore water samplers (PWS) to sample for isotope analysis (1) only water, (2) soil under laboratory conditions, and (3) soil in the field comparing the results with cryogenic extraction (CE). In (1) and (2), no significant differences between source and water extracted with PWS were detected with a mean absolute difference (MAD) always lower than 2 ‰ for δ 2 H and 1 ‰ for δ 18 O. In (2), CE water was more enriched than PWS-extracted water, with a MAD respect to source water of roughly 8 ‰ for δ 2 H and 4 ‰ for δ 18 O. In (3), PWS water was enriched relative to CE water by 3 ‰ for δ 2 H and 0.9 ‰ for δ 18 O. The latter result may be due to the distinct water portions sampled by the two methods. Large pores, easily sampled by PWS, likely retain recent, and enriched, summer precipitation while small pores, only sampled by CE, possibly retain isotopically depleted water from previous winter precipitation or irrigation inputs. Accuracy and precision were greater for PWS relative to CE. PWS is therefore suggested as viable tool to extract soil water for stable isotope analysis, particularly for soils used in this study (sandy and silty loams).

Infiltration into cropped soils: effect of rain and sodium adsorption ratio-impacted irrigation water.

PubMed

Suarez, Donald L; Wood, James D; Lesch, Scott M

2008-01-01

The sodium adsorption ratio (SAR) and salinity criteria for water suitability for irrigation have been developed for conditions where irrigation water is the only water source. It is not clear that these criteria are applicable to environments where there is a combination of rain and irrigation during the growing season. The interaction of rainfall with irrigation water is expected to result in increased sodicity hazard because of the low electrical conductivity of rain. In this study we examined the effects of irrigation waters of SAR 2, 4, 6, 8, and 10 mmol(1/2) L(-1/2) and electrical conductivities of 1 and 2 dS m(-1) on the infiltration rate of two soils with alternating cycles of rain (simulated with a rainfall sprinkler) and irrigation water, separated by drying cycles. The infiltration rate of surface samples from two soils, Kobase silty clay (fine, smectitic, frigid, Torrertic Haplustept) and Glendive very fine sandy loam (coarse-loamy, mixed superactive, calcareous, frigid Aridic Ustifluvent) were evaluated under alfalfa (Medicago sativa) cropped conditions for over 140 d and under full canopy cover. Reductions in infiltration were observed for both soils for SAR above 2, and the reductions became more severe with increasing SAR. Saturated hydraulic conductivity measurements taken from undisturbed cores at the end of the experiment were highly variable, suggesting that in situ infiltration measurements may be preferred when evaluating SAR effects.

Effects of novel nitrification and urease inhibitors (DCD/TZ and 2-NPT) on N2O emissions from surface applied urea: An incubation study

NASA Astrophysics Data System (ADS)

Ni, Kang; Kage, Henning; Pacholski, Andreas

2018-02-01

A 41-day incubation trial was conducted to test the single and combined effects of the novel urease (N-(2-Nitrophenyl) phosphoric triamide, 2-NPT) and nitrification inhibitors (mixture of dicyandiamide and 1H-1,2,4-triazole, DCD/TZ) on N2O emissions and underlying soil processes from a North German sandy loam soil. The effects of treatment on N2O emission were determined using static closed chamber incubation and detected using a photo-acoustic gas monitor. The emission processes were strongly related to soil mineral N and pH dynamics, obtained from destructive sampling of replicate incubation chambers. The combined use of urease and nitrification inhibitors slightly increased the reduction of N2O compared with single use of the nitrification inhibitor (69% vs. 61%). The small amount of soil used in the incubation and the depletion of labile carbon by air drying and pre-incubation caused very low initial N2O emissions, and glucose addition significantly stimulated N2O emission by supplying labile carbon. The urease inhibitor significantly reduced simultaneously determined qualitative NH3 emissions in either urea alone (90%) or urea plus nitrification inhibitor treatment (82%). These results highlighted the potential of the combined use of urease and nitrification inhibitors with urea application to mitigate soil NH3 and N2O emissions.

Proximal Gamma-Ray Spectroscopy to Predict Soil Properties Using Windows and Full-Spectrum Analysis Methods

PubMed Central

Mahmood, Hafiz Sultan; Hoogmoed, Willem B.; van Henten, Eldert J.

2013-01-01

Fine-scale spatial information on soil properties is needed to successfully implement precision agriculture. Proximal gamma-ray spectroscopy has recently emerged as a promising tool to collect fine-scale soil information. The objective of this study was to evaluate a proximal gamma-ray spectrometer to predict several soil properties using energy-windows and full-spectrum analysis methods in two differently managed sandy loam fields: conventional and organic. In the conventional field, both methods predicted clay, pH and total nitrogen with a good accuracy (R2 ≥ 0.56) in the top 0–15 cm soil depth, whereas in the organic field, only clay content was predicted with such accuracy. The highest prediction accuracy was found for total nitrogen (R2 = 0.75) in the conventional field in the energy-windows method. Predictions were better in the top 0–15 cm soil depths than in the 15–30 cm soil depths for individual and combined fields. This implies that gamma-ray spectroscopy can generally benefit soil characterisation for annual crops where the condition of the seedbed is important. Small differences in soil structure (conventional vs. organic) cannot be determined. As for the methodology, we conclude that the energy-windows method can establish relations between radionuclide data and soil properties as accurate as the full-spectrum analysis method. PMID:24287541

Nitrogen release from urea with different coatings.

PubMed

Campos, Odirley R; Mattiello, Edson Marcio; Cantarutti, Reinaldo Bertola; Vergütz, Leonardus

2018-01-01

Coatings or urease inhibitors are designed to reduce losses of ammonia [NH 3(g) ] from urea fertilizers. However, nitrogen (N) release and its effects on soil solution have not previously been evaluated under standardized conditions in soils. In this study, the urea fertilizers were incubated in chambers filled with sandy loam soil, adapted for the collection of NH 3(g) and soil solution by centrifugation. In the fast-release N fertilizers, around 93% and 100% of urea-N applied was recovered within the first hours of incubation. In contrast, in the slow-release N fertilizers, less than 40% of urea-N applied, was recovered at 19 days of incubation. The maximum N release from the fertilizers followed the order: UP1 (106%) ≈ UNBPT (102%) ≈ urea (93%) > USP2 (57%) ≈ USP3 (57%) > USP4 (31%) ≈ USP5 (18%). NH 3(g) volatilization accounted for only 3% of the applied N in the slow-release fertilizers, which corresponded to about 88% less than the NH 3(g) loss from prilled urea. This study demonstrated distinct N release patterns, which changed the N dynamics in the soil. Some coatings effectively delayed urea release from granules and reduced NH 3(g) gas losses, while other were not efficient. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.