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Sample records for loam hagerstown silty

  1. Effect of biochar amendment on nitrate retention in a silty clay loam soil

    Directory of Open Access Journals (Sweden)

    Angela Libutti

    2016-08-01

    Full Text Available Biochar incorporation into agricultural soils has been proposed as a strategy to decrease nutrient leaching. The present study was designed to assess the effect of biochar on nitrate retention in a silty clay loam soil. Biochar obtained from the pyrogasification of fir wood chips was applied to soil and tested in a range of laboratory sorption experiments. Four soil treatments were considered: soil only (control, soil with 2, 4 and 8% of biochar by mass. The Freundlich sorption isotherm model was used to fit the adsorbed amount of nitrate in the soil-biochar mixtures. The model performed very well in interpreting the experimental data according to a general linear regression (analysis of co-variance statistical approach. Nitrate retention in the soilbiochar mixtures was always higher than control, regardless the NO3 – concentration in the range of 0-400 mg L–1. Different sorption capacities and intensities were detected depending on the biochar application rate. The highest adsorption capacity was observed in the soils added with 2 and 4% of biochar, respectively. From the results obtained is possible to infer that nitrate retention is higher at lower biochar addition rate to soil (2 and 4% and at lower nitrate concentration in the soil water solution. These preliminary laboratory results suggest that biochar addition to a typical Mediterranean agricultural soil could be an effective management option to mitigate nitrate leaching.

  2. IMPACT OF THE REPEATED TRACTOR PASSES ON SOME PHYSICAL PROPERTIES OF SILTY LOAM SOIL

    Directory of Open Access Journals (Sweden)

    Dubravko Filipović

    2011-12-01

    Full Text Available The aim of this paper was to quantify soil compaction induced by tractor traffic on untilled wet silty loam soil (Mollic Fluvisol. Changes in penetration resistance, bulk density and total porosity were measured for detecting the soil compaction. Treatments include ten passes of a four-wheel drive tractor with the engine power of 54.0 kW and weight of 3560 kg (1580 kg on the front axle and 1980 kg on the rear axle, 2.41 m distance between axles. The tyres on the tractor were cross-ply, front 11.2-24 and rear 16.9-30, with the inflation pressure of 160 kPa and 100 kPa, respectively. The speed of tractor during passes over experimental plots was 5.0 km h-1. In comparison to control, each tractor pass induced an increase in soil penetration resistance at all depths, and the average increment ratios, determined as the average of all layers, were 9.8, 18.5 and 26.1% after one, five and ten passes, respectively. The bulk density also increased with number of tractor passes, but with less percentage increasing. The increment ratios comparison to the control were 3.6, 9.5 and 12.9% after one, five and ten passes, respectively. The total porosity decreased with the number of passes, and the decrement ratios were 4.5, 16.5 and 20.8% after one, five and ten passes, respectively.

  3. USE OF THE “ROTHC” MODEL TO SIMULATE SOIL ORGANIC CARBON DYNAMICS ON A SILTY-LOAM INCEPTISOL IN NORTHERN ITALY UNDER DIFFERENT FERTILIZATION PRACTICES

    Directory of Open Access Journals (Sweden)

    Rosa Francaviglia

    2014-01-01

    Full Text Available We evaluated the efficiency of the RothC model to simulate Soil Organic Carbon (SOC dynamics after 12 years of organic and mineral fertilization practices in a study area located in northern Italy, on a silty-loam Inceptisol with a rotation including tomato, maize and alfalfa. The model performance was assessed by RMSE and EF coefficients. RothC simulated well observed SOC decreases in 71 samples (RMSE=7.42; EF=0.79, while performed with less accuracy when considering all samples (96 samples; RMSE=12.37; EF=0.58, due to the fact that the model failed in case of measured SOC increases (25 samples; RMSE=20.77; EF=-0.038. The model was used to forecast the SOC dynamics over a 50 year period under the same pedoclimatic conditions. Only clay contents >15% allowed to predict increasing levels of SOC respect to the starting values.

  4. Geology and sinkhole development of the Hagerstown Valley : phase II summary report.

    Science.gov (United States)

    2014-06-01

    As a part of this study, karst areas of the Hagerstown, Mason Dixon, Williamsport, Clear Spring, and Hedgesville : quadrangles (western half of the Hagerstown Valley) were mapped in detail to determine the distribution of karst : features relative to...

  5. Effects of Conventional and Conservation Tillage on Soil Hydraulic Properties of a Silty-loamy Soil

    DEFF Research Database (Denmark)

    Wahl, Niels Arne; Bens, O.; Buczko, U.

    2004-01-01

    Infiltration into soils is strongly correlated with macroporosity. Under agricultural land use, the properties of the macropore network are governed by the applied management and tillage system. On an experimental site with a silt loam soil partly under conventional and conservation tillage, the ......, conservation tillage could possibly offer a means to reduce surface runoff and flood generation in agricultural landscapes dominated by silty-loamy soils. d 2...

  6. Hagerstown Community College: Building a High Tech Base.

    Science.gov (United States)

    Regional Technology Strategies, Inc., Carrboro, NC.

    This document describes the Advanced Technology Center (ATC) at Hagerstown Community College (HCC) (Maryland), created in 1990 as a response to the region's economic decline. The ATC is a partnership between the College, industry, and government to help promote industrial modernization and regional competitiveness through training, demonstration,…

  7. Geology and sinkhole development of the Hagerstown valley : phase II : [research summary].

    Science.gov (United States)

    2014-06-01

    The objective of this study was to map the western half of the Hagerstown Valley to : determine the distribution of karst features relative to bedrock geologic units using a : global positioning system (GPS).

  8. Linear Shrinkage Behaviour of Compacted Loam Masonry Blocks

    Directory of Open Access Journals (Sweden)

    NAWAB ALI LAKHO

    2017-04-01

    Full Text Available Walls of wet loam, used in earthen houses, generally experience more shrinkage which results in cracks and less compressive strength. This paper presents a technique of producing loam masonry blocks that are compacted in drained state during casting process in order to minimize shrinkage. For this purpose, loam masonry blocks were cast and compacted at a pressure of 6 MPa and then dried in shade by covering them in plastic sheet. The results show that linear shrinkage of 2% occurred which is smaller when compared to un-compacted wet loam walls. This implies that the loam masonry blocks compacted in drained state is expected to perform better than un-compacted wet loam walls.

  9. Metal (Cu, Cd and Zn) removal and stabilization during multiple soil washing by saponin.

    Science.gov (United States)

    Gusiatin, Zygmunt Mariusz; Klimiuk, Ewa

    2012-01-01

    The influence of multiple saponin washing on copper, cadmium and zinc removal and stability in three types of soils (loamy sand, loam, silty clay) was investigated. Distribution of metals and their mobility measured as the ratio of exchangeable form to the sum of all fractions in soils was differential. After single washing the highest efficiency of metal removal was obtained in loamy sand (82-90%) and loam (67-88%), whereas the lowest in silty clay (39-62%). In loamy sand and loam metals had higher mobility factors (44-61% Cu, 60-76% Cd, and 68-84% Zn) compared to silty clay (9% Cu, 28% Cd and 36% Zn). Triplicate washing led to increase both efficiency of metal removal and percentage content of their stable forms. In consequence, fractional patterns for metals before and after treatment changed visibly as a result of their redistribution. Based on the redistribution index, the most stable metal (mainly in residual and organic fractions) after triplicate washing was Cu in loamy sand and loam. For silty clay contaminated with Cd, effective metal removal and its stabilization required a higher number of washings. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Characteristics of Soil and Organic Carbon Loss Induced by Water Erosion on the Loess Plateau in China.

    Science.gov (United States)

    Li, Zhongwu; Nie, Xiaodong; Chang, Xiaofeng; Liu, Lin; Sun, Liying

    2016-01-01

    Soil erosion has been a common environmental problem in the Loess Plateau in China. This study aims to better understand the losses of soil organic carbon (SOC) induced by water erosion. Laboratory-simulated rainfall experiments were conducted to investigate the characteristics of SOC loss induced by water erosion. The applied treatments included two rainfall intensities (90 and 120 mm h-1), four slope gradients (10°, 15°, 20°, and 25°), and two typical soil types- silty clay loam and silty loam. Results showed that the sediment OC enrichment ratios (ERoc) in all the events were relative stable with values ranged from 0.85 to1.21 and 0.64 to 1.52 and mean values of 0.98 and 1.01 for silty clay loam and silty loam, respectively. Similar to the ERoc, the proportions of different sized particles in sediment showed tiny variations during erosion processes. No significant correlation was observed between ERoc values and the proportions of sediment particles. Slope, rainfall intensity and soil type almost had no impact on ERoc. These results indicate that the transportation of SOC during erosion processes was nonselective. While the mean SOC loss rates for the events of silty clay loam and silty loam were 0.30 and 0.08 g m-2 min-1, respectively. Greater differences in SOC loss rates were found in events among different soil types. Meanwhile, significant correlations between SOC loss and soil loss for all the events were observed. These results indicated that the amount of SOC loss was influenced primarily by soil loss and the SOC content of the original soil. Erosion pattern and original SOC content are two main factors by which different soils can influence SOC loss. It seems that soil type has a greater impact on SOC loss than rainfall characteristics on the Loess Plateau of China. However, more kinds of soils should be further studied due to the special formation processes in the Loess Plateau.

  11. Analysis on Wetting Deformation Properties of Silty Clay

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    Xinrong Liu

    2014-06-01

    Full Text Available Changes in water level that cause deformation and stability problems often occur in foundation pit engineering. Water damage is one of the main problems that will lead to disasters in foundation pit engineering. Research findings with regard to properties of wetting deformation due to water damage can be applied not only in foundation pit engineering, slope engineering, hydraulic engineering, and mining engineering but also in related issues in the field of theoretical research and practice. In this study, the characteristics of silty clay deformation after wetting are examined from the perspective of the effect of wetting on the side wall of foundation pit, and wetting experiments on silty clay of a selected area’s stratum located in Chongqing Municipality are conducted under different confining pressures and stress levels through a multi-function triaxial apparatus. Then, laws of silty clay wetting deformation are obtained, and the relationship between wetting stress level and wetting deformation amount is also figured out. The study reveals that the maximum values of wetting deformation under different confining pressures have appear at a particular stress level; therefore, the related measures should be taken to avoid this deformation in the process of construction.

  12. Attachment of Escherichia coli and enterococci to particles in runoff.

    Science.gov (United States)

    Soupir, Michelle L; Mostaghimi, Saied; Dillaha, Theo

    2010-01-01

    Association of Escherichia coli and enterococci with particulates present in runoff from erodible soils has important implications for modeling the fate and transport of bacteria from agricultural sources and in the selection of management practices to reduce bacterial movement to surface waters. Three soils with different textures were collected from the Ap horizon (silty loam, silty clay loam, and loamy fine sand), placed in portable box plots, treated with standard cowpats, and placed under a rainfall simulator. Rainfall was applied to the plots until saturation-excess flow occurred for 30 min, and samples were collected 10, 20, and 30 min after initiation of the runoff event. The attachment of E. coli and enterococci to particles present in runoff was determined by a screen filtration and centrifugation procedure. Percentage of E. coli and enterococci attached to particulates in runoff ranged from 28 to 49%, with few statistically significant differences in attachment among the three soils. Similar partitioning release patterns were observed between E. coli and enterococci from the silty loam (r = 0.57) and silty clay loam soils (r = 0.60). At least 60% of all attached E. coli and enterococci were associated particles within an 8- to 62-microm particle size category. The results indicate that the majority of fecal bacteria attach to and are transported with manure colloids in sediment-laden flow regardless of the soil texture.

  13. Bioremediating silty soil contaminated by phenanthrene, pyrene ...

    African Journals Online (AJOL)

    ... followed in the order of their increasing molecular weight. The synergy of the bacterial isolates and the biosurfactant produced from B. vulgaris agrowaste could be used in environmental bioremediation of PAHs even in silty soil. Keywords: Benz(a)anthracene, benzo(a)pyrene, bioremediation, biosurfactant, Beta vulgaris, ...

  14. Assessment of the mechanical properties of sisal fiber-reinforced silty clay using triaxial shear tests.

    Science.gov (United States)

    Wu, Yankai; Li, Yanbin; Niu, Bin

    2014-01-01

    Fiber reinforcement is widely used in construction engineering to improve the mechanical properties of soil because it increases the soil's strength and improves the soil's mechanical properties. However, the mechanical properties of fiber-reinforced soils remain controversial. The present study investigated the mechanical properties of silty clay reinforced with discrete, randomly distributed sisal fibers using triaxial shear tests. The sisal fibers were cut to different lengths, randomly mixed with silty clay in varying percentages, and compacted to the maximum dry density at the optimum moisture content. The results indicate that with a fiber length of 10 mm and content of 1.0%, sisal fiber-reinforced silty clay is 20% stronger than nonreinforced silty clay. The fiber-reinforced silty clay exhibited crack fracture and surface shear fracture failure modes, implying that sisal fiber is a good earth reinforcement material with potential applications in civil engineering, dam foundation, roadbed engineering, and ground treatment.

  15. Assessment of the Mechanical Properties of Sisal Fiber-Reinforced Silty Clay Using Triaxial Shear Tests

    Directory of Open Access Journals (Sweden)

    Yankai Wu

    2014-01-01

    Full Text Available Fiber reinforcement is widely used in construction engineering to improve the mechanical properties of soil because it increases the soil’s strength and improves the soil’s mechanical properties. However, the mechanical properties of fiber-reinforced soils remain controversial. The present study investigated the mechanical properties of silty clay reinforced with discrete, randomly distributed sisal fibers using triaxial shear tests. The sisal fibers were cut to different lengths, randomly mixed with silty clay in varying percentages, and compacted to the maximum dry density at the optimum moisture content. The results indicate that with a fiber length of 10 mm and content of 1.0%, sisal fiber-reinforced silty clay is 20% stronger than nonreinforced silty clay. The fiber-reinforced silty clay exhibited crack fracture and surface shear fracture failure modes, implying that sisal fiber is a good earth reinforcement material with potential applications in civil engineering, dam foundation, roadbed engineering, and ground treatment.

  16. Evaluation of the ecotoxicological impact of the organochlorine chlordecone on soil microbial community structure, abundance, and function.

    Science.gov (United States)

    Merlin, Chloé; Devers, Marion; Béguet, Jérémie; Boggio, Baptiste; Rouard, Nadine; Martin-Laurent, Fabrice

    2016-03-01

    The insecticide chlordecone applied for decades in banana plantations currently contaminates 20,000 ha of arable land in the French West Indies. Although the impact of various pesticides on soil microorganisms has been studied, chlordecone toxicity to the soil microbial community has never been assessed. We investigated in two different soils (sandy loam and silty loam) exposed to different concentrations of CLD (D0, control; D1 and D10, 1 and 10 times the agronomical dose) over different periods of time (3, 7, and 32 days): (i) the fate of chlordecone by measuring (14)C-chlordecone mass balance and (ii) the impact of chlordecone on microbial community structure, abundance, and function, using standardized methods (-A-RISA, taxon-specific quantitative PCR (qPCR), and (14)C-compounds mineralizing activity). Mineralization of (14)C-chlordecone was inferior below 1 % of initial (14)C-activity. Less than 2 % of (14)C-activity was retrieved from the water-soluble fraction, while most of it remained in the organic-solvent-extractable fraction (75 % of initial (14)C-activity). Only 23 % of the remaining (14)C-activity was measured in nonextractable fraction. The fate of chlordecone significantly differed between the two soils. The soluble and nonextractable fractions were significantly higher in sandy loam soil than in silty loam soil. All the measured microbiological parameters allowed discriminating statistically the two soils and showed a variation over time. The genetic structure of the bacterial community remained insensitive to chlordecone exposure in silty loam soil. In response to chlordecone exposure, the abundance of Gram-negative bacterial groups (β-, γ-Proteobacteria, Planctomycetes, and Bacteroidetes) was significantly modified only in sandy loam soil. The mineralization of (14)C-sodium acetate and (14)C-2,4-D was insensitive to chlordecone exposure in silty loam soil. However, mineralization of (14)C-sodium acetate was significantly reduced in soil

  17. Effect of Drainage Conditions on Cone Penetration Testing in Silty Soils

    DEFF Research Database (Denmark)

    Poulsen, Rikke; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

    2011-01-01

    This paper discusses the challenges that occur when performing Cone Penetration Tests (CPT) in silty soil due to changes in drainage conditions. In this paper, CPT results from various papers and researchers are collected and interpreted. Results from cone penetrations tests with various penetrat......This paper discusses the challenges that occur when performing Cone Penetration Tests (CPT) in silty soil due to changes in drainage conditions. In this paper, CPT results from various papers and researchers are collected and interpreted. Results from cone penetrations tests with various...

  18. New insights into the wind-dust relationship in sandblasting and direct aerodynamic entrainment from wind tunnel experiments

    KAUST Repository

    Parajuli, Sagar Prasad; Zobeck, Ted M.; Kocurek, Gary; Yang, Zong-Liang; Stenchikov, Georgiy L.

    2016-01-01

    Numerous parameterizations have been developed for predicting wind erosion, yet the physical mechanism of dust emission is not fully understood. Sandblasting is thought to be the primary mechanism, but recent studies suggest that dust emission by direct aerodynamic entrainment can be significant under certain conditions. In this work, using wind tunnel experiments, we investigated some of the lesser understood aspects of dust emission in sandblasting and aerodynamic entrainment for three soil types, namely clay, silty clay loam, and clay loam. First, we explored the role of erodible surface roughness on dust emitted by aerodynamic entrainment. Second, we compared the emitted dust concentration in sandblasting and aerodynamic entrainment under a range of wind friction velocities. Finally, we explored the sensitivity of emitted dust particle size distribution (PSD) to soil type and wind friction velocity in these two processes. The dust concentration in aerodynamic entrainment showed strong positive correlation, no significant correlation, and weak negative correlation, for the clay, silty clay loam, and clay loam, respectively, with the erodible soil surface roughness. The dust in aerodynamic entrainment was significant constituting up to 28.3, 41.4, and 146.4% compared to sandblasting for the clay, silty clay loam, and clay loam, respectively. PSD of emitted dust was sensitive to soil type in both sandblasting and aerodynamic entrainment. PSD was sensitive to the friction velocity in aerodynamic entrainment but not in sandblasting. Our results highlight the need to consider the details of sandblasting and direct aerodynamic entrainment processes in parameterizing dust emission in global/regional climate models.

  19. New insights into the wind-dust relationship in sandblasting and direct aerodynamic entrainment from wind tunnel experiments

    KAUST Repository

    Parajuli, Sagar Prasad

    2016-01-22

    Numerous parameterizations have been developed for predicting wind erosion, yet the physical mechanism of dust emission is not fully understood. Sandblasting is thought to be the primary mechanism, but recent studies suggest that dust emission by direct aerodynamic entrainment can be significant under certain conditions. In this work, using wind tunnel experiments, we investigated some of the lesser understood aspects of dust emission in sandblasting and aerodynamic entrainment for three soil types, namely clay, silty clay loam, and clay loam. First, we explored the role of erodible surface roughness on dust emitted by aerodynamic entrainment. Second, we compared the emitted dust concentration in sandblasting and aerodynamic entrainment under a range of wind friction velocities. Finally, we explored the sensitivity of emitted dust particle size distribution (PSD) to soil type and wind friction velocity in these two processes. The dust concentration in aerodynamic entrainment showed strong positive correlation, no significant correlation, and weak negative correlation, for the clay, silty clay loam, and clay loam, respectively, with the erodible soil surface roughness. The dust in aerodynamic entrainment was significant constituting up to 28.3, 41.4, and 146.4% compared to sandblasting for the clay, silty clay loam, and clay loam, respectively. PSD of emitted dust was sensitive to soil type in both sandblasting and aerodynamic entrainment. PSD was sensitive to the friction velocity in aerodynamic entrainment but not in sandblasting. Our results highlight the need to consider the details of sandblasting and direct aerodynamic entrainment processes in parameterizing dust emission in global/regional climate models.

  20. Applicability of zeolites in potassium and nitrate retention in different soil types

    Directory of Open Access Journals (Sweden)

    Pavlović Jelena B.

    2017-01-01

    Full Text Available Environmental protection and sustainable agricultural production require the use of inexpensive and environmentally acceptable soil supplements. Objectives of this study were to investigate the influence of the addition of the natural zeolite – clinoptilolite (NZ and its iron(III-modified form (FeZ on the potassium and nitrate leaching from sandy, silty loam and silty clay soils. The zeolites were added in two amounts: 0.5 (FeZ and 1.0 wt. % (NZ and FeZ. The experiments were carried out in columns organized in eight experimental systems containing unamended (control specimens and amended soils. The concentration of K+ and NO3–N in the leachates was monitored during 7 days. The obtained results indicate that the K+ and NO3–N leaching mainly depends on the soil type and pH of the soil. The NZ and FeZ addition has the highest impact on the K+ retention in the acidic sandy soil. The highest NO3–N retention is obtained with FeZ in acidic silty loam soil. The K+ leaching kinetics for all the studied soils follow the Avrami kinetics model with the parameter n < 1. This study demonstrates that NZ and FeZ can be a good soil supplement for the K+ retention for all studied soils and in the NO3–N retention for silty loam and silty clay soils. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172018

  1. Dynamic Characteristics of Saturated Silty Soil Ground Treated by Stone Column Composite Foundation

    Directory of Open Access Journals (Sweden)

    Yongxiang Zhan

    2014-01-01

    Full Text Available A shaking table model test was carried out to develop an understanding of the performance improvement of saturated silty soil ground using stone column composite foundation as reinforcement. It is found that at less than 0.161 g loading acceleration, soil between piles has not yet been liquefied, the response acceleration scarcely enlarges, and the shear displacement almost does not appear in silty soil. At 0.252 g loading acceleration, as a result of liquefaction of soil between piles, the response acceleration increases rapidly and reaches its peak, and the shear displacement of silty soil increases significantly. At 0.325 g loading acceleration, the integral rigidity of foundation decreases greatly, which reduces its capability of vibration transmission and result in the response acceleration amplification coefficient is less than that at the former loading acceleration, but the shear displacement of silty soil further increases. The stone column composite foundation can greatly reduce both the shear displacement and the settlement of ground compared with untreated foundation. Under the condition of 7-degree seismic fortification, the design meets seismic resistance requirements.

  2. Correlation Between Cone Penetration Rate And Measured Cone Penetration Parameters In Silty Soils

    DEFF Research Database (Denmark)

    Poulsen, Rikke; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

    2013-01-01

    This paper shows, how a change in cone penetration rate affects the cone penetration measurements, hence the cone resistance, pore pressure, and sleeve friction in silty soil. The standard rate of penetration is 20 mm/s, and it is generally accepted that undrained penetration occurs in clay while...... drained penetration occurs in sand. When lowering the penetration rate, the soil pore water starts to dissipate and a change in the drainage condition is seen. In intermediate soils such as silty soils, the standard cone penetration rate may result in a drainage condition that could be undrained......, partially or fully drained. However, lowering the penetration rate in silty soils has a great significance because of the soil permeability, and only a small change in penetration rate will result in changed cone penetration measurements. In this paper, analyses will be done on data from 15 field cone...

  3. Evaluation of fertilization-to-planting and fertilization-to-harvest intervals for safe use of noncomposted bovine manure in Wisconsin vegetable production.

    Science.gov (United States)

    Ingham, Steven C; Fanslau, Melody A; Engel, Rebecca A; Breuer, Jeffry R; Breuer, Jane E; Wright, Thomas H; Reith-Rozelle, Judith K; Zhu, Jun

    2005-06-01

    Fresh bovine manure was mechanically incorporated into loamy sand and silty clay loam Wisconsin soils in April 2004. At varying fertilization-to-planting intervals, radish, lettuce, and carrot seeds were planted; crops were harvested 90, 100, 110 or 111, and 120 days after manure application. As an indicator of potential contamination with fecal pathogens, levels of Escherichia coli in the manure-fertilized soil and presence of E. coli on harvested vegetables were monitored. From initial levels of 4.0 to 4.2 log CFU/g, E. coli levels in both manure-fertilized soils decreased by 2.4 to 2.5 log CFU/g during the first 7 weeks. However, E. coli was consistently detected from enriched soil samples through week 17, perhaps as a result of contamination by birds and other wildlife. In the higher clay silty clay loam soil, the fertilization-to-planting interval affected the prevalence of E. coli on lettuce but not on radishes and carrots. Root crop contamination was consistent across different fertilization-to-harvest intervals in silty clay loam, including the National Organic Program minimum fertilization-to-harvest interval of 120 days. However, lettuce contamination in silty clay loam was significantly (P < 0.10) affected by fertilization-to-harvest interval. Increasing the fertilization-to-planting interval in the lower clay loamy sand soil decreased the prevalence of E. coli on root crops. The fertilization-to-harvest interval had no clear effect on vegetable contamination in loamy sand. Overall, these results do not provide grounds for reducing the National Organic Program minimum fertilization-to-harvest interval from the current 120-day standard.

  4. Interaction of radionuclides with diluvium loams

    International Nuclear Information System (INIS)

    Martyanov, V.V.; Guskov, A.V.; Tkachenko, A.V.; Prozorov, L.B.; Karlina, O.K.

    2005-01-01

    Full text of publication follows: Primary goal of this research was to study the interaction of radioactive liquid waste with diluvium loams. A geology-hydro-geological characterisation of the RADON-site facility, located in the Southern Region of Russia, is given. According to the results of laboratory and field studies, the hydro-geological parameters of diluvium loams were designed, and their mineral and grain structures were investigated. It was established, that loams have low filtration properties. Definition of filtration coefficients (Kf) under laboratory conditions has shown low values (hydraulic gradient J=10, Kf = 8.10 -4 m/day). But the field experiment has shown, that Kf values vary from 0.1 up to 0.04 m/day with a gradient of J=1! (It is important to point at the selection of the initial data for modelling migration). Mineral structure: quartz - 43 %, montmorillonite - 28 %, hydro-micas - 17 %, iron hydroxides - 5 %, feldspar - 3,7 %, kaolinite - 2 %, carbonates - 1 %, organics - 0,3 %. The content of minerals known as good sorbents, makes up to 52 %. Laboratory experiments dedicated to the determination of sorption isotherms for various radionuclides were carried out. As a result, distribution coefficients (Kd) for 90 Sr, 137 Cs, 60 Co, 238 Pu were determined. Geology-hydro-geological and radiochemical data were used for the schematization of the system. Then, the mathematical modelling and forecasting of radionuclide migration was carried out. Two conservative scenarios were considered - full destruction of the waste matrices + water flow (lateral and vertical direction). As migrating components 90 Sr, 137 Cs, 60 Co, 238 Pu were considered. 90 Sr, 137 Cs, 60 Co, 238 Pu have different mobility due to their Kd ranging from tens and hundreds up to thousand ml/g depending on the properties of the diluvium loams. Initial radionuclide concentrations were as follow: 137 Cs -1.32.10 8 Bq/l, 60 Co - 2.52.10 7 Bq/l, 90 Sr - 1.81.10 7 Bq/l, 238 Pu - 7.78.10 6

  5. Environmental Assessment for Alternate Water Supply System, Joint Base Langley-Eustis, Newport News, Virginia

    Science.gov (United States)

    2013-06-01

    sanitary sewer facilities at JBLE- FE. The existing water distribution system consists of approximately 50 miles of pipe, a water booster pumping station...layers consist of clay , silty clay , or silty clay loam. None of these soils are classified as Prime Farmland soils. Environmental Assessment for...ODUS owns and operates the sanitary sewer facilities at JBLE-FE. Newport News owns and operates the sanitary sewer facilities on the private land in

  6. 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

    Science.gov (United States)

    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.

  7. STABILISATION OF SILTY CLAY SOIL USING CHLORIDE

    Directory of Open Access Journals (Sweden)

    TAMADHER T. ABOOD

    2007-04-01

    Full Text Available The object of this paper is to investigate the effect of adding different chloride compounds including (NaCl, MgCl2, CaCl2 on the engineering properties of silty clay soil. Various amounts of salts (2%, 4%, and 8% were added to the soil to study the effect of salts on the compaction characteristics, consistency limits and compressive strength. The main findings of this study were that the increase in the percentage of each of the chloride compounds increased the maximum dry density and decrease the optimum moisture content. The liquid limit, plastic limit and plasticity index decreased with the increase in salt content. The unconfinedcompressive strength increased as the salt content increased.

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

    Science.gov (United States)

    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 (pdiatomite 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.

  9. Aplicación potencial universal de bioindicadores del suelo: su evaluación en tres ecosistemas templados

    OpenAIRE

    González, Mirta G; Gallardo, Juan F; Gómez, Elena; Masciandaro, Grazia; Ceccanti, Brunello; Pajares, Silvia

    2007-01-01

    Three selected soils from three countries with temperate climates have been analyzed. Two of the soils are silty loams (Buenos Aires, Argentina, and Salamanca, Spain) and the third one is a sandy loam (Peccioli, Italy). Soil samples representing three agricultural managements were obtained from the top layer (0-10 cm), i.e. intensively cultivated, cultivated and undisturbed native soils. Soil organic carbon (SOC), total nitrogen (Nt), ATP, urease, protease, phosphatase, b-glucosidase, dehydro...

  10. Determination of the equivalent intergranular void ratio - Application to the instability and the critical state of silty sand

    Directory of Open Access Journals (Sweden)

    Nguyen Trung-Kien

    2017-01-01

    Full Text Available This paper presents an experimental study of mechanical response of natural Camargue silty sand. The analysis of test results used the equivalent intergranular void ratio instead of the global void ratio. The calculation of equivalent intergranular void ratio requires the determination of parameter b which represents, physically, the fraction of active fines participating on the chain forces network, hence the strength of the soil. A new formula for determining the parameter b by using an approach based on the coordination number distribution and probability calculation is proposed. The validation of the developed relationship was done through back-analysis of published datasets in literature on the effect of fines content on silty sand behavior. It is shown that the equivalent intergranular void ratio calculated with the b value obtained by the new formula is able to provide strong correlation to not only the critical state of but also the onset of instability of various silty sands, in different terms as peak deviator stress, peak stress ratio or cyclic resistance. Therefore, it is suggested that the use of the equivalent void ratio concept and the new b calculating formula is highly desirable in predicting of the silty sand behavior.

  11. EFFECTS OF ALKALINE SANDY LOAM ON SULFURIC SOIL ACIDITY AND SULFIDIC SOIL OXIDATION

    Directory of Open Access Journals (Sweden)

    Patrick S. Michael

    2015-08-01

    Full Text Available  In poor soils, addition of alkaline sandy loam containing an adequate proportion of sand, silt and clay would add value by improving the texture, structure and organic matter (OM for general use of the soils. In acid sulfate soils (ASS, addition of alkaline sandy would improve the texture and leach out salts as well as add a sufficient proportion of OM for vegetation establishment. In this study, addition of alkaline sandy loam into sulfuric soil effectively increased the pH, lowered the redox and reduced the sulfate content, the magnitude of the effects dependent on moisture content. Addition of alkaline sandy loam in combination with OM was highly effective than the effects of the lone alkaline sandy loam. When alkaline sandy was added alone or in combination with OM into sulfidic soil, the effects on pH and the redox were similar as in the sulfuric soil but the effect on sulfate content was variable. The effects under aerobic conditions were higher than under anaerobic conditions. The findings of this study have important implications for the general management of ASS where lime availability is a concern and its application is limited.International Journal of Environment Volume-4, Issue-3, June-August 2015Page: 42-54

  12. Interpretation of Cone Penetration Testing in Silty Soils Conducted under Partially Drained Conditions

    DEFF Research Database (Denmark)

    Holmsgaard, Rikke; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

    2016-01-01

    The standard penetration rate used in cone penetration tests (CPTs) is 20 mm=s, regardless of soil type, which yields fully drained penetration in sand and fully undrained penetration in clay. However, for silty soils that represent an intermediate grain size composition and unique characteristic...

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

    Science.gov (United States)

    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.

  14. Sorption and migration of 137Cs attached to organic materials of tea in silty clay soil

    International Nuclear Information System (INIS)

    Yuecel, H.; Oezmen, A.

    1996-01-01

    The effect of the organic material of tea on the adsorption behavior of 137 Cs on the silty clay soil has been examined by batch experiments, using 137 Cs extracted tea contaminated by the Chernobyl accident, with water. The variation of K d values was studied as a function of contact time and a volume-solid ratio (V/m). The equilibrium time of 137 Cs extracted from the tea is slower by 9 times than that of 137 Cs + ions for the silty clay soil. The V/m ratio did not affect the 137 Cs adsorption strongly. The sorption of 137 Cs extracted form the tea in terms of the distribution coefficient K d is higher (a factor of 2.5) than that of 137 Cs + ions. This result indicates that 137 Cs-complexes with organic materials of tea are much sorbed than 137 C + ions on the silty clay soil. The migration of 137 Cs extracted from the tea in the silty clay soil has been studied under a steady flow of tea-extract by using a soil zone apparatus. The 137 Cs concentrations contained in both effluent fractions and in soil samples were measured using a HPGe detector. The distribution patterns of 137 Cs in the layers of the soil zone were obtained as one- and two-dimensional. The migration of 137 Cs extracted from the tea in soil is mainly influenced by flow. The results indicate that the migration of 137 Cs-complexes with organic materials and 137 Cs adsorbed fine silts cannot be described by such a K d based on ion-exchange reactions, but it is important to consider the moving mechanism of particulates besides ion-exchange reactions. (Author)

  15. effect of tractor forward speed on sandy loam soil physical ...

    African Journals Online (AJOL)

    Dr Obe

    Ilorin on a sandy loam soil to evaluate the effect of the imposition of different .... of the blade is 10.5cm. ... arranged in an inverted cone shape with ... replicates were taken for each speed run. The ..... Thakur, T. C; A. Yadav; B. P. Varshney and.

  16. Periodically operated bioreactors for the treatment of soils and leachates

    International Nuclear Information System (INIS)

    Irvine, R.L.; Cassidy, D.P.

    1995-01-01

    Limited contaminant bioavailability at concentrations above the required cleanup level reduces biodegradation rate and renders solid-phase bioremediation more cost effective than complete treatment in a bioslurry reactor. Slurrying followed by solid-phase bioremediation combines the advantages and minimizes the weaknesses of each treatment method when used alone. Periodic aeration during solid-phase bioremediation has the potential to lower treatment costs relative to continuous aeration. A biological treatment system consisting of slurrying followed by periodic aeration in solid-phase sequencing batch reactors (SP-SBRs) was developed and tested in the laboratory using a silty loam contaminated predominantly with the plasticizer bis(2-ethylhexyl)phthalate (BEHP) or (DEHP) and a silty clay loam contaminated with diesel fuel. The first experiment evaluated the effect of water content and mixing time during slurrying on subsequent treatment in continuously aerated solid-phase bioreactors. The second experiment compared treatment of slurried soil in SP-SBRs using three different periodic aeration strategies with continuous aeration

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

    Science.gov (United States)

    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.

  18. Investigating the Effect of Soil Texture and Fertility on Evapotranspiration and Crop Coefficient of Maize Forage

    Directory of Open Access Journals (Sweden)

    M. Ghorbanian Kerdabadi

    2017-02-01

    Full Text Available Introduction: Crop coefficient varies in different environmental conditions, such as deficit irrigation, salinity and intercropping. The effect of soil fertility and texture of crop coefficient and evapotranspiration of maize was investigated in this study. Low soil fertility and food shortages as a stressful environment for plants that makes it different evapotranspiration rates of evapotranspiration calculation is based on the FAO publication 56. Razzaghi et al. (2012 investigate the effect of soil type and soil-drying during the seed-filling phase on N-uptake, yield and water use, a Danish-bred cultivar (CV. Titicaca was grown in field lysimeters with sand, sandy loam and sandy clay loam soil. Zhang et al (2014 were investigated the Effect of adding different amounts of nitrogen during three years (from 2010 to 2012 on water use efficiency and crop evapotranspiration two varieties of winter wheat. The results of their study showed. The results indicated the following: (1 in this dry land farming system, increased N fertilization could raise wheat yield, and the drought-tolerant Changhan No. 58 showed a yield advantage in drought environments with high N fertilizer rates; (2 N application affected water consumption in different soil layers, and promoted wheat absorbing deeper soil water and so increased utilization of soil water; and (3 comprehensive consideration of yield and WUE of wheat indicated that the N rate of 270 kg/ha for Changhan No. 58 was better to avoid the risk of reduced production reduction due to lack of precipitation; however, under conditions of better soil moisture, the N rate of 180 kg/ha was more economic. Materials and Methods: The study was a factorial experiment in a completely randomized design with three soil texture treatment, including silty clay loam, loam and sandy-loam soil and three fertility treatment, including without fertilizer, one and two percent fertilizer( It was conducted at the experimental farm in

  19. influence of tillage practices on physical properties of a sandy loam

    African Journals Online (AJOL)

    DR. AMINU

    many regions of the world if the mechanics of tillage effects on soil physical properties is to be well understood. Thus, the ... tillage systems on water storage of a sandy loam soil after 22 years of ..... Soil infiltration ... and processes. Academy ...

  20. Optimising crop production and nitrate leaching in China: Measured and simulated effects of straw incorporation and nitrogen fertilisation

    DEFF Research Database (Denmark)

    Manevski, Kiril; Børgesen, Christen Duus; Li, Xiaoxin

    2016-01-01

    model Daisy for estimating crop production and nitrate leaching from silty loam fields in the NCP. The main objectives were to: i) calibrate and validate Daisy for the NCP pedo-climate and field management conditions, and ii) use the calibrated model and the field data in a multi-response analyses...

  1. Uniaxial compression tests on diesel contaminated frozen silty soil specimens

    International Nuclear Information System (INIS)

    Chenaf, D.; Stampli, N.; Bathurst, R.; Chapuis, R.P.

    1999-01-01

    Results of a uniaxial, unconfined compression test on artificial diesel-contaminated and uncontaminated frozen silty soils are discussed. The testing program involved 59 specimens. The results show that for the same fluid content, diesel contamination reduced the strength of the frozen specimens by increasing the unfrozen water content. For example, in specimens containing 50 per cent diesel oil of the fluid content by weight the maximum strength was reduced by 95 per cent compared to the strength of an uncontaminated specimen. Diesel contamination was also shown to contribute to the slippage between soil particles by acting as a lubricant, thus accelerating the loss of compressive strength.13 refs., 18 figs

  2. Effectiveness of the GAEC cross-compliance standard Ploughing in good soil moisture conditions in soil structure protection

    Directory of Open Access Journals (Sweden)

    Maria Teresa Dell'Abate

    2011-08-01

    Full Text Available Researches have been carried out within the framework on the EFFICOND Project, focused at evaluating the effectiveness of the standards of Good Agricultural and Environmental Conditions (GAECs established for Cross Compliance implementation under EC Regulation 1782/2003. In particular the standard 3.1b deals with soil structure protection through appropriate machinery use, with particular reference to ploughing in good soil moisture conditions. The study deals with the evaluation of soil structure after tillage in tilth and no-tilth conditions at soil moisture contents other than the optimum water content for tillage. The Mean Weight Diameter (MWD of water stable aggregates was used as an indicator of tillage effectiveness. The study was carried out in the period 2008-2009 at six experimental farms belonging to Research Centres and Units of the Italian Agricultural Research Council (CRA with different pedo-climatic and cropping conditions. Farm management and data collection in the different sites were carried out by the local CRA researchers and technicians. The comparison of MWD values in tilth and no tilth theses showed statistically significant differences in most cases, depending on topsoil texture. On clay, clay loam, silty clay, and silty clay loam topsoils a general and significant increase of MWD values under no tilth conditions were observed. No significant differences were observed in silt loam and sandy loam textures, probably due to the weak soil structure of the topsoils. Moreover, ploughing in good soil moisture condition determined higher crop production and less weed development than ploughing in high soil moisture conditions.

  3. Assessment of structural stability of a degraded sandy clay loam soil ...

    African Journals Online (AJOL)

    The effects of bare, two legumes and four grasses cover treatments on the structural stability of a sandy clay loam Ultisol were studied within a two year period. The experiment was of a randomised complete block design with seven treatments. The legume treatments were Centrosema pubescens (Ce) and Pueraria ...

  4. Resistive heating enhanced soil vapor extraction of chlorinated solvents from trichloroethylene contaminated silty, low permeable soil

    NARCIS (Netherlands)

    Zutphen, M. van; Heron, G.; Enfield, C.G.; Christensen, T.H.

    1998-01-01

    A 2D-laboratory box experiment (12 x 56 x 116 cm) was conducted to simulate the enhancement of soil vapor extraction by the application of low frequency electrical heating Uoule heating) for the remediation of a low permeable, silty soil contaminated with trichloroethylene. Joule heating enlarged

  5. Bioavailability of cerium oxide nanoparticles to Raphanus sativus L. in two soils.

    Science.gov (United States)

    Zhang, Weilan; Musante, Craig; White, Jason C; Schwab, Paul; Wang, Qiang; Ebbs, Stephen D; Ma, Xingmao

    2017-01-01

    Cerium oxide nanoparticles (CeO 2 NP) are a common component of many commercial products. Due to the general concerns over the potential toxicity of engineered nanoparticles (ENPs), the phytotoxicity and in planta accumulation of CeO 2 NPs have been broadly investigated. However, most previous studies were conducted in hydroponic systems and with grain crops. For a few studies performed with soil grown plants, the impact of soil properties on the fate and transport of CeO 2 NPs was generally ignored even though numerous previous studies indicate that soil properties play a critical role in the fate and transport of environmental pollutants. The objectives of this study were to evaluate the soil fractionation and bioavailability of CeO 2 NPs to Raphanus sativus L (radish) in two soil types. Our results showed that the silty loam contained slightly higher exchangeable fraction (F1) of cerium element than did loamy sand soil, but significantly lower reducible (F2) and oxidizable (F3) fractions as CeO 2 NPs concentration increased. CeO 2 NPs associated with silicate minerals or the residue fraction (F4) dominated in both soils. The cerium concentration in radish storage root showed linear correlation with the sum of the first three fractions (r 2  = 0.98 and 0.78 for loamy sand and silty loam respectively). However, the cerium content in radish shoots only exhibited strong correlations with F1 (r 2  = 0.97 and 0.89 for loamy sand and silty loam respectively). Overall, the results demonstrated that soil properties are important factors governing the distribution of CeO 2 NPs in soil and subsequent bioavailability to plants. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  6. Comparative evaluation of the effect of rock phosphate and monoammonium phosphate on plant P: Nutrition in Sod-podzolic and peat soils

    International Nuclear Information System (INIS)

    Bogdevitch, I.; Tarasiuk, S.; Putyatin, Yu.; Seraya, T.

    2002-01-01

    The direct application of finely ground rock phosphate (RP) imported from Russia has been suggested as an alternative to the almost twice more expensive water-soluble monoammonium phosphate (MAP) on acid (moderately limed) Sod-podzolic and peat soils. A pot experiment was conducted in 1997-1998 for a comparative evaluation of P availability from RP and MAP using the 32 P isotope dilution technique. The lupine was grown on Sod-podzolic silty clay loam soil with pH 6.0 and a medium level of available P. Ryegrass plants were grown on peat soil with pH 4.9 and a low level of native soil P fertility. Application of RP and MAP at a rate of 40 mg P/kg soil supplied similar moderate mount of P to lupine plants. The Pdff values, i.e. the fractions of P in the plants derived from the applied RP and MAP, were 7.4 and 8.4%, respectively. The application of the same P fertilizers to the peat soil had different effects on P nutrition of ryegrass plants. The Pdff values were 14.9% for RP and 22.1% for MAP. It may be concluded that for most annual crops water-soluble P forms such as MAP should be preferred. Direct application of RP is recommended for plants with an adequate rhizosphere ability to utilize P, such as lupine on acid Sod-podzolic silty clay loam soils (pH 137 Cs on contaminated, moderately limed Sod-podzolic silty clay loam and peat soils. These soils are widely spread in the radioactive contaminated area of Belarus after the Chernobyl accident. Direct application of RP may be one of the effective countermeasures for the decrease of 137 Cs transfer from the contaminated acid soils to crop production. (author)

  7. Response of fed dung composted with rock phosphate on yield and ...

    African Journals Online (AJOL)

    Field experiment was conducted on silty clay loam soil at the research farm of Khyber Pakhtunkhwa Agricultural University, Peshawar to study the effect of RP fed dung composted with RP on the yield, yield components and P uptake of maize (Zea mays. L. Azam). The fertilizers, N, P and K, were applied at the rate of 120- ...

  8. Inoculation effects of two South African cyanobacteria strains on ...

    African Journals Online (AJOL)

    Two South African cyanobacteria strains (coded 3g and 7e) of the genus Nostoc were evaluated for improvement of the aggregate stability of a silty loam soil with low organic C content and compared with Nostoc strain 9v isolated from a Tanzanian soil. The soil was either cropped with maize or non-cropped and inoculated ...

  9. Application of Polyacrylamide (PAM) through Lay-Flat Polyethylene Tubing: Effects on Infiltration, Erosion, N and P Transport, and Corn Yield.

    Science.gov (United States)

    McNeal, J P; Krutz, L J; Locke, M A; Kenty, M M; Atwill, R L; Pickelmann, D M; Bryant, C J; Wood, C W; Golden, B R; Cox, M S

    2017-07-01

    Polyacrylamides (PAMs), when applied as a soil amendment, purportedly improve soil infiltration, decrease erosion, and reduce offsite agrochemical transport. The effect of PAM on infiltration, erosion, agrochemical transport, and crop yield when applied in furrow to mid-southern US production systems has not been evaluated. The objective of this study was to assess PAM effects on infiltration, erosion, corn ( L.) grain yield, and nitrogen (N) and phosphorus (P) transport when applied at 10 mg L through lay-flat polyethylene tubing. A 2-yr field study was conducted at the Mississippi State Delta Research and Extension Center in Stoneville, MS, on a Dundee silt loam and a Forestdale silty clay loam. The experimental design was a randomized complete block with four replications of each treatment: irrigated plus no PAM (control) and irrigated plus PAM at 10 mg L. Each irrigation event delivered 102 mm of water at 18.9 L m per furrow, and runoff was captured in a holding tank on the lower end of each plot. Pooled over year and soil texture, PAM increased infiltration and corn grain yield by 6% ( ≤ 0.0398). Polyacrylamide effects on the offsite transport of sediment and N and P were inconsistent, varying across year and soil texture. Results indicate that PAM improves infiltration and corn grain yield on silt loam and silty clay loam textured soils; however, further research is required before PAM can be recommended as a best management practice for mitigating erosion and offsite agrochemical transport in mid-southern production systems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

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

    Science.gov (United States)

    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.

  11. Effects of aluminium water treatment residuals, used as a soil amendment to control phosphorus mobility in agricultural soils.

    Science.gov (United States)

    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.

  12. Processing Uranium-Bearing Materials Containing Coal and Loam

    Energy Technology Data Exchange (ETDEWEB)

    Civin, V; Prochazka, J [Research and Development Laboratory No. 3 of the Uranium Industry, Prague, Czechoslovakia (Czech Republic)

    1967-06-15

    Among the ores which are classified as low-grade in the CSSR are mixtures of coal and bentonitic loam of tertiary origin, containing approximately 0.1% U and with a moisture content at times well above 20-30%. The uranium is held mainly by the carbonaceous component. Conventional processing of these materials presents various difficulties which are not easily overcome. During leaching the pulp thickens and frequently becomes pasty, due to the presence of montmorillonites. Further complications arise from the high sorption capacity of the materials (again primarily due to montmorillonites) and poor sedimentation of the viscous pulps. In addition, the materials are highly refractory to the leaching agents. The paper presents experience gained in solving the problems of processing these ores. The following basic routes were explored: (1) separation of the carbonaceous and loamy components: The organic component appears to be the main activity carrier. Processing the concentrated material upon separation of the inactive or less active loam may not only remove the thixotropic behaviour but also substantially reduce the cost of the ore treatment; (2) 'liquifying' the pulps or preventing the thickening of the pulp by addition of suitable agents; (3) joint acid or carbonate processing of the materials in question with current ore types; (4) removal or suppression of thixotropic behaviour by thermal pretreatment of the material; and (5) application of the 'acid cure' method. The first method appears to be the most effective, but it presents considerable difficulties due to the extreme dispersion of the carbonaceous phase and further research is being carried out. Methods 2 and 3 proved to be unacceptable. Method 4, which includes roasting at 300-400{sup o}C, is now being operated on an industrial scale. The final method has also shown definite advantages for particular deposits of high montmorillonite content material. (author)

  13. Copper effects on bacterial activity of estuarine silty sediments

    Science.gov (United States)

    Almeida, Adelaide; Cunha, Ângela; Fernandes, Sandra; Sobral, Paula; Alcântara, Fernanda

    2007-07-01

    Bacteria of silty estuarine sediments were spiked with copper to 200 μg Cu g -1 dry weight sediment in order to assess the impact of copper on bacterial degradation of organic matter and on bacterial biomass production. Bacterial density was determined by direct counting under epifluorescence microscopy and bacterial production by the incorporation of 3H-Leucine. Leucine turnover rate was evaluated by 14C-leucine incorporation and ectoenzymatic activities were estimated as the hydrolysis rate of model substrates for β-glucosidase and leucine-aminopeptidase. The presence of added copper in the microcosms elicited, after 21 days of incubation, generalised anoxia and a decrease in organic matter content. The non-eroded surface of the copper-spiked sediment showed, when compared to the control, a decrease in bacterial abundance and significant lower levels of bacterial production and of leucine turnover rate. Bacterial production and leucine turnover rate decreased to 1.4% and 13% of the control values, respectively. Ectoenzymatic activities were also negatively affected but by smaller factors. After erosion by the water current in laboratory flume conditions, the eroded surface of the control sediment showed a generalised decline in all bacterial activities. The erosion of the copper-spiked sediment showed, however, two types of responses with respect to bacterial activities at the exposed surface: positive responses of bacterial production and leucine turnover rate contrasting with slight negative responses of ectoenzymatic activities. The effects of experimental erosion in the suspended cells were also different in the control and in the copper-spiked sediment. Bacterial cells in the control microcosm exhibited, when compared to the non-eroded sediment cells, decreases in all activities after the 6-h suspension. The response of the average suspended copper-spiked sediment cell differed from the control by a less sharp decrease in ectoenzymatic activities and

  14. Interrill sediment enrichment of P and C from organically and conventionally farmed silty loams

    Science.gov (United States)

    Kuhn, N. J.

    2012-04-01

    Globally, between 0.57 and 1.33 Pg of soil organic carbon (SOC) may be affected by interrill processes. Also, a significant amount of phosphorus (P) is contained in the surface soil layer transformed by raindrop impact, runoff and crust formation. In the EU, the P content of a crusted (2 mm) surface layer corresponds to 4 to 40 kg ha-1 of P on arable land (1.094 mil km2). Therefore, the role of interrill processes for nutrient cycling and the global carbon cycle requires close attention. Interrill erosion is a complex phenomen on involving the detachment, transport and deposition of soil particles by raindrop impacted flow. Resistance to interrill erosion varies between soils depending on their physical, chemical and mineralogical properties. In addition, significant changes in soil resistance to interrill erosion occur during storms as a result of changes in surface roughness, cohesion and particle size. As a consequence, erosion on interrill areas is selective, moving the most easily detached small and/or light soil particles. This leads to the enrichment of clay, phosphorous (P)and carbon (C). Such enrichment in interrill sediment is well documented, however, the role of interrill erosion processes on the enrichment remains unclear. Enrichment of P and C in interrill sediment is attributed to the preferential erosion of the smaller, lighter soil particles. In this study, the P and organic C content of sediment generated from two Devon silts under conventional (CS) and organic (OS) soil management were examined. Artificial rainfall was applied to the soils using two rainfall scenarios of differing intensity and kinetic energy to determine the effects on the P and C enrichment in interrill sediment. Interrill soil erodibility was lower on the OS, irrespective of rainfall intensity. Sediment from both soils showed a significant enrichment in P and C compared to the bulk soil. However, sediment from the OS displayed a much greater degree of P enrichment. This shows that the net P export from organically farmed soils is not reduced by a similar degree than soil erosion compared to conventional soil management. The enrichment of P and C in the interrill sediment was not directly related to SOC, P content of the soil and soil interrill erodibility. A comparison of soil and sediment properties indicates that crusting, P and C content as well as density and size of eroded aggregate fragments control P and C enrichment. Due to complex and dynamic interactions between P, SOC and interrill erosional processes, the nutrient and C status of sediments cannot be predicted based on soil P content, SOC or interrill erodibility alone. Clearly, further research on crust formation and the composition of fragments generated by aggregate breakdown and their transport in raindrop impacted flow under different rainfall conditions is required. Attaining this critical missing knowledge would enable a comprehensive assessment of the benefits of organic farming on nutrient budgets, off-site effects of interrill erosion and its role in the global C cycle.

  15. Anisotropy of the porosity in a silty loam soil under continuous no tillage management

    OpenAIRE

    Soracco, Carlos Germán; Lozano, Luis A.; Gelati, Pablo R.; Sarli, Guillermo O.; Filgueira, Roberto R.

    2008-01-01

    La superficie bajo siembra directa (SD) se incrementa continuamente en la Republica Argentina. Existen trabajos que muestran una orientación preferencial de los poros en sentido horizontal cerca de la superficie de suelos bajo SD. El objetivo específico de este trabajo fue evaluar la conductividad hidráulica saturada del horizonte superficial en sentido vertical y horizontal en SD continua con descompactación (SDCD) respecto de un testigo de SD sin descompactacion (SDSD) para determinar la ex...

  16. Challenges of conservation agriculture practices on silty soils. Effects on soil pore and gas transport characteristics in North-eastern Italy

    DEFF Research Database (Denmark)

    Piccoli, Ilaria; Schjønning, Per; Lamandé, Mathieu

    2017-01-01

    highlighted low transmission properties of the silty soils independently from agronomic management. Both air permeability and relative gas diffusivity showed poor aerated conditions being generallytreatments affected the transmission properties only in the coarsest soil...... of this study was to evaluate the effect of CA practices on gas transport characteristics in the silty soils of the Veneto Region (North-Eastern Italy). In 2010, a field experiment comparing CA practices (no-tillage, cover crop and residues retention) to conventional intensive tillage (IT) system...... was established in four farms located in the Veneto low plain. In fall 2015, 144 undisturbed 100 cm3 soil cores where collected at two different layers (3–6.5 cm and 20–23.5 cm) and analysed for air-filled porosity, air permeability, gas diffusivity and soil structure indices derived. Gas transport measurements...

  17. Pore structure characteristics after two years biochar application to a sandy loam field

    DEFF Research Database (Denmark)

    Sun, Zhencai; Arthur, Emmanuel; de Jonge, Lis Wollesen

    2015-01-01

    the effects of birch wood biochar (20, 40, and 100 Mg ha−1) applied to a sandy loam on soil total porosity and pore structure indices. Bulk and intact soil samples were collected for physicochemical analyses and water retention and gas diffusivity measurements between pF 1.0 and pF 3.0. Biochar application...

  18. Velocidad y Tiempo de Centrifugación para Extraer Nematodos Fitoparásitos del Suelo.

    Directory of Open Access Journals (Sweden)

    Volcy Charles

    1980-09-01

    Full Text Available An experiment was carried out in order to compare different combination of speeds and times of centrifugation to isolate Helicotylenchus dihystera, Meloidogyne incognita and Tylenchulus semipenetrans. The centrifugation-sugar screening method was used. Two loam soils were use with natural infestations of the above mentioned nematodes and a silty loam with natural infestation of H. dihystera. It was concluded that the combination with more consistent results to isolate the spiral eelworm was the centrifugation at 1000 rpm (200 g for 5 minutes in both cycles, while the combinations with best result to extract the other two species was the centrifugation at 2000 rpm (800 g for 3 minutes in both cycles.

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

    Science.gov (United States)

    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.

  20. Final Oahe Dam/Lake Oahe Master Plan Missouri River, South Dakota and North Dakota

    Science.gov (United States)

    2010-09-01

    silty loams with moderate erosion and poor permeability. Normally used for pastureland. Sansarc- Opal : clays with minor erosion and permeability...One active sand and gravel mining area is located on Oahe project lands at Fort Yates, North Dakota. There is also a small amount of sand and...consist of sand and gravel deposits and Pierre Shale. The sand and gravel deposits are mined for road construction materials and concrete aggregate

  1. Respirable dust and quartz exposure from three South African farms with sandy, sandy loam, and clay soils.

    Science.gov (United States)

    Swanepoel, Andrew J; Kromhout, Hans; Jinnah, Zubair A; Portengen, Lützen; Renton, Kevin; Gardiner, Kerry; Rees, David

    2011-07-01

    To quantify personal time-weighted average respirable dust and quartz exposure on a sandy, a sandy loam, and a clay soil farm in the Free State and North West provinces of South Africa and to ascertain whether soil type is a determinant of exposure to respirable quartz. Three farms, located in the Free State and North West provinces of South Africa, had their soil type confirmed as sandy, sandy loam, and clay; and, from these, a total of 298 respirable dust and respirable quartz measurements were collected between July 2006-November 2009 during periods of major farming operations. Values below the limit of detection (LOD) (22 μg · m(-3)) were estimated using multiple 'imputation'. Non-parametric tests were used to compare quartz exposure from the three different soil types. Exposure to respirable quartz occurred on all three farms with the highest individual concentration measured on the sandy soil farm (626 μg · m(-3)). Fifty-seven, 59, and 81% of the measurements on the sandy soil, sandy loam soil, and clay soil farm, respectively, exceeded the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) of 25 μg · m(-3). Twelve and 13% of respirable quartz concentrations exceeded 100 μg · m(-3) on the sandy soil and sandy loam soil farms, respectively, but none exceeded this level on the clay soil farm. The proportions of measurements >100 μg · m(-3) were not significantly different between the sandy and sandy loam soil farms ('prop.test'; P = 0.65), but both were significantly larger than for the clay soil farm ('prop.test'; P = 0.0001). The percentage of quartz in respirable dust was determined for all three farms using measurements > the limit of detection. Percentages ranged from 0.5 to 94.4% with no significant difference in the median quartz percentages across the three farms (Kruskal-Wallis test; P = 0.91). This study demonstrates that there is significant potential for over-exposure to respirable quartz in

  2. Final Environmental Assessment Addressing a Proposed Airfield Drainage Improvement Project, Dobbins Air Reserve Base, Georgia

    Science.gov (United States)

    2013-11-01

    components of the herbaceous layer. Soil in the wetland is chru·actetized by a samrated, low chroma silty clay loam. Hydrology apperu·s to be from overland...Mrutin and meet the installation’s water requirements for consmnption and fire-fighting pmposes. Sanitary /Sewer Wastewater System. Wastewater... clay pipes ranging in size from 6 to 10 inches in diameter, with some newer collection lines const111cted of reinforced concrete pipe. Sewage is

  3. Non-cohesive silt turbidity current flow processes; insights from proximal sandy-silt and silty-sand turbidites, Fiordland, New Zealand

    Science.gov (United States)

    Strachan, Lorna J.; Bostock, Helen C.; Barnes, Philip M.; Neil, Helen L.; Gosling, Matthew

    2016-08-01

    Silt-rich turbidites are commonly interpreted as distal marine deposits. They are associated with interlaminated clay and silt deposition from the upper and rear portions of turbidity currents. Here, multibeam bathymetry and shallow sediment core data from the intra-slope Secretary Basin, Fiordland, New Zealand, located laminar) flows that have undergone a variety of up-dip flow transformations. Most flows were initially erosive followed by deposition of partitioned 2- or 3- phase mixed mode flows that include high-density transitional and laminar flows that can be fore- or after-runners to low-density turbulent flow sections. Turbulence is inferred to have been suppressed in high-density flows by increasing flow concentration of both sands and silts. The very fine and fine sand modal grain sizes of sandy-silt and silty-sand turbidites are significantly coarser than classical abyssal plain silt turbidites and are generally coarser than overbank silt turbidites. While the low percentage of clays within Secretary Basin sandy-silt and silty-sand turbidites represents a fundamental difference between these and other silt and mud turbidites, we suggest these beds represent a previously undescribed suite of proximal continental slope deposits.

  4. Effects of Surfactant on Geotechnical Characteristics of Silty Soil

    International Nuclear Information System (INIS)

    Rahman, Z.A.; Sahibin, A.R.; Lihan, T.; Idris, W.M.R.; Sakina, M.

    2013-01-01

    Surfactants are often used as a cleaning agent for restoration of oil-contaminated soil. However the effect of surfactant on the geotechnical properties of soil is not clearly understood. In this study, the effects of surfactant on silty soil were investigated for consistency index, compaction, permeability and shear strength. Sodium dodecyl sulfate (SDS) was used in this study to prepare the surfactant-treated soil. Our results showed that the soil with added surfactant exhibited a decrease in liquid and plastic limit values. Maximum dry densities increased and optimum moisture contents decreased as contents of added surfactant were increased. The presence of surfactant assists the soil to achieve maximum density at lower water content. The addition of surfactant decreased the permeability of soil from 6.29 x 10 -4 to 1.15 x 10 -4 ms -1 . The shear strength of soil with added surfactant was examined using the undrained unconsolidated triaxial tests. The results showed that the undrained shear strength, Cu was significantly affected, decreased from 319 kPa to 50 kPa for soil with 20 % of added surfactant. The results of this study showed that the presence of surfactant in soil can modify the mechanical behaviour of the soil. (author)

  5. Loss of surface horizon of an irrigated soil detected by radiometric images of normalized difference vegetation index.

    Science.gov (United States)

    Fabian Sallesses, Leonardo; Aparicio, Virginia Carolina; Costa, Jose Luis

    2017-04-01

    The use of the soil in the Humid Pampa of Argentina has changed since the mid-1990s from agricultural-livestock production (that included pastures with direct grazing) to a purely agricultural production. Also, in recent years the area under irrigation by central pivot has been increased to 150%. The waters used for irrigation are sodium carbonates. The combination of irrigation and rain increases the sodium absorption ratio of soil (SARs), consequently raising the clay dispersion and reducing infiltration. This implies an increased risk of soil loss. A reduction in the development of white clover crop (Trifolium repens L.) was observed at an irrigation plot during 2015 campaign. The clover was planted in order to reduce the impact of two maize (Zea mays L.) campaigns under irrigation, which had increased soil SAR and deteriorated soil structure. SPOT-5 radiometric normalized difference vegetation index (NDVI) images were used to determine two zones of high and low production. In each zone, four random points were selected for further geo-referenced field sampling. Two geo-referenced measures of effective depth and surface soil sampling were carried out in each point. Texture of soil samples was determined by Pipette Method of Sedimentation Analysis. Data exploratory analysis showed that low production zone had a media effective depth = 80 cm and silty clay loam texture, while high production zone had a media effective depth > 140 cm and silt loam texture. The texture class of the low production zone did not correspond to prior soil studies carried out by the INTA (National Institute of Agricultural Technology), which showed that those soil textures were silt loam at surface and silty clay loam at sub-surface. The loss of the A horizon is proposed as a possible explanation, but further research is required. Besides, the need of a soil cartography actualization, which integrates new satellite imaging technologies and geo-referenced measurements with soil sensors is

  6. Effect of vermicomposts from wastes of the wine and alcohol industries in the persistence and distribution of imidacloprid and diuron on agricultural soils.

    Science.gov (United States)

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

    2009-06-24

    The persistence and distribution of diuron (D) and imidacloprid (I) in soils amended or not with winery vermicomposts were recorded for several months. Sandy loam (S1) and silty clay loam (S2) soils with organic carbon contents of Diuron was dissipated more rapidly except in the unamended soil S1 with DT(50) values of 259 days. The addition of vermicomposts to S1 soil decreased the persistence of D, and high amounts of DPMU (40%) and DPU (20%) metabolites were found. In unamended and amended S2 soils, the persistence of D was lower than in S1 (DT(50) < 42 days) but only DPMU was determined (up to 5%). Different simulation models from FOCUS guidelines were applied to the experimental data. No relationship between pesticide degradation and soil enzyme activities was found.

  7. Impact of tillage intensity on clay loam soil structure

    DEFF Research Database (Denmark)

    Daraghmeh, Omar; Petersen, Carsten; Munkholm, Lars Juhl

    Soil structure and structural stability are key parameters in sustainable soil management and optimum cropping practices. Locally and temporally adapted precision tillage may improve crop performance while at the same time reduce environmental impacts. The main objective of this study...... was to improve the knowledge of precision tillage practices through characterizing the effect of varied tillage intensities on structural properties of a clay loam soil. A field experiment was conducted using a randomized complete block design with two main factors, i.e. operational speed (OS, 2 levels......) and rotovating speed (RS, 3 levels). The tillage was conducted using a PTO-driven rotovator equipped to measure angular velocity. The effect of traffic compaction, made directly after tillage, was measured on soil taken from wheel track (WT) compared with soil outside wheel track (NWT). Soil samples from 0-3 cm...

  8. Distribution of Soil Organic Carbon and the Influencing Factors in An Oasis Farmland Area

    Directory of Open Access Journals (Sweden)

    WANG Ze

    2014-08-01

    Full Text Available The soil organic carbon(SOC of a typical oasis farmland in middle part of Manasi county of Xinjiang was used as the research ob原 ject. Using remote sensing and lab analysis techniques, influences of soil texture, terrain, land uses, and crop types on SOC content of farmland were studied. Results showed that the SOC distribution in farmland of Manasi was mainly determined by comprehensive natural environmental factors. The SOC content decreased along with the increasing soil depth. For soil textures, the SOC content from high to low was clay loam>powder loam>silty loam. Slope direction had significantly positive correlations with SOC contents at 0~30 cm and 30~60 cm, while altitude and SOC content at 60~100 cm were significantly positive correlation. The SOC content of orchard was the highest, and the uncultivated land was the lowest under different land-use patterns. For different crop planting systems, the order of SOC content was corn field >wine grapes field>cotton field, and the difference was significant.

  9. Impact of chemical leaching on permeability and cadmium removal from fine-grained soils.

    Science.gov (United States)

    Lin, Zhongbing; Zhang, Renduo; Huang, Shuang; Wang, Kang

    2017-08-01

    The aim of this study was to investigate the influence of chemical leaching on permeability and Cd removal from fine-grained polluted soils. Column leaching experiments were conducted using two types of soils (i.e., artificially Cd-polluted loam and historically polluted silty loam). Chemical agents of CaCl 2 , FeCl 3 , citric acid, EDTA, rhamnolipid, and deionized water were used to leach Cd from the soils. Results showed that organic agents reduced permeability of both soils, and FeCl 3 reduced permeability of loam soil, compared with inorganic agents and deionized water. Entrapment and deposition of colloids generated from the organic agents and FeCl 3 treatments reduced the soil permeability. The peak Cd effluence from the artificially polluted loam columns was retarded. For the artificially polluted soils treated with EDTA and the historically polluted soils with FeCl 3 , Cd precipitates were observed at the bottom after chemical leaching. When Cd was associated with large colloid particles, the reduction of soil permeability caused Cd accumulation in deeper soil. In addition, the slow process of disintegration of soil clay during chemical leaching might result in the retardation of peak Cd effluence. These results suggest the need for caution when using chemical-leaching agents for Cd removal in fine-grained soils.

  10. Slow reaction of soil structure to conservation agriculture practices in Veneto silty soils (North-Easter Italy)

    Science.gov (United States)

    Piccoli, Ilaria; Camarotto, Carlo; Lazzaro, Barbara; Furlan, Lorenzo; Morari, Francesco

    2017-04-01

    Soil structure plays a pivotal role in soil functioning and can inform of the degradation of the soil ecosystem. Intensive and repeated tillage operations have been known to negatively affect the soil structure characteristics while conservation agriculture (CA) practices were demonstrated to improve soil structure and related ecosystem services. The aim of this study is to evaluate the effect of conservation agriculture practices on total porosity, pore size distribution, pore architecture and morphology on silty soils of Veneto low-lying plain (North-Eastern Italy). Experimental design was established in 2010 on 4 farms in North-Eastern Italy to compare conventional intensive tillage system "IT" versus conservation agriculture "CA" (no-tillage, cover-crop and residue retention). 96 samples were collected in 2015 at four depths down to 50 cm depth, and investigated for porosity from micro to macro by coupling mercury intrusion porosimetry (MIP) (0.0074-100 µm) and x-ray computed microtomography (µCT) (>26 µm). Pore morphology and architecture were studied from 3D images analysis and MIP pore size curve. Ultramicroporosity class (0.1-5 μm) positively responded to CA after 5-yr of practices adoption while no significant effects were observed in the x-ray µCT domain (> 26 µm). Silty soils of Veneto plain showed a slow reaction to conservation agriculture because of the low soil organic carbon content and poor aggregate stability. Nevertheless the positive influence of CA on ultramicroporosity, which is strictly linked to soil organic carbon (SOC) stabilization, indicated that a virtuous cycle was initiated between SOC and porosity, hopefully leading to well-developed macropore systems and, in turn, enhanced soil functions and ecosystem services.

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

    DEFF Research Database (Denmark)

    Woldetsadik, Desta; Drechsel, Pay; Keraita, Bernard

    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...... 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...

  12. Modeling the pullout characteristics of welded wire mats embedded in silty sand

    International Nuclear Information System (INIS)

    Sampaco, C.L.; Anderson, L.R.; Nielson, M.R.

    1994-01-01

    This paper is an outgrowth of the on-going research on discrete finite element modeling of welded wire mesh reinforced soil structures such as the welded wire and RSE walls. The stiffness characteristics of the wire mesh-soil interfaces are modeled by a nonlinear hyperbolic relationship between the applied pullout stress and the associated mat placement. The relevant parameters are estimated from laboratory pullout tests that were conducted for welded wire mats embedded on silty sand. Since the bulk of the pullout resistance of welded wire mesh reinforcements is derived from the bearing resistance of the transverse wires that constitute the test mats. This feature permits proper evaluation of actual interface parameters for the actual reinforced soil structures in which the actual lengths of the mats are longer (i.e. more transverse members) than the specimen used in the laboratory pullout tests. The resulting pullout stress-displacement formulations are then verified by comparing the predicted pullout resistance to the existing specifications and design methods for estimated the pullout capacities of grid reinforcements. 22 refs., 13 figs

  13. Combined mild soil washing and compost-assisted phytoremediation in treatment of silt loams contaminated with copper, nickel, and chromium.

    Science.gov (United States)

    Sung, Menghau; Lee, Chi-Yi; Lee, Suen-Zone

    2011-06-15

    A new soil remediation option, combining the soil washing process using pure water followed by the compost-assisted phytoextraction, is evaluated using silt loams contaminated with plating wastewater containing Cu, Ni, and Cr. Plants utilized in this study are the rapeseeds, sunflowers, tomatoes, and soapworts. Phytoextraction operation was carried out in pot experiments over a period of 4 months. Metal concentrations in roots and shoots of plants were analyzed upon completion of each pot experiment. Hypothesis testing was employed in assessing the significance of difference in the experimental data. Results indicated that the rapeseed, a hyperaccumulator, is most effective in extracting metals from the compost-amended silt loams. The fast-growing sunflowers and tomatoes are comparable to rapeseeds in accumulating metals despite their relatively low metal concentrations in tissues. Bioaccumulation coefficients obtained for all plants are less than one, indicating that phytostabilization rather than phytoextraction is the dominant mechanism at this simulated final-phase condition. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. The effect of particle size on sorption of estrogens, androgens and progestagens in aquatic sediment

    Energy Technology Data Exchange (ETDEWEB)

    Sangster, Jodi L.; Oke, Hugues; Zhang, Yun; Bartelt-Hunt, Shannon L., E-mail: sbartelt2@unl.edu

    2015-12-15

    Highlights: • Two sediments were used to evaluate the effects of particle size on steroid sorption. • Sorption capacity did not increase with decreasing particle size for all steroids. • Particle interactions affect the distribution of steroids within the whole sediments. • Preferential sorption to fine particles was observed. - Abstract: There is growing concern about the biologic effects of steroid hormones in impacted waterways. There is increasing evidence of enhanced transport and biological effects stemming from steroid hormones associated with soils or sediments; however, there are limited studies evaluating how steroid hormone distribution between various particle sizes within whole sediments affects steroid fate. In this study, sorption of 17β-estradiol, estrone, progesterone, and testosterone was evaluated to different size fractions of two natural sediments, a silty loam and a sandy sediment, to determine the steroid sorption capacity to each fraction and distribution within the whole sediment. Sorption isotherms for all steroid hormones fit linear sorption models. Sorption capacity was influenced more by organic carbon content than particle size. Interactions between size fractions were found to affect the distribution of steroids within the whole sediments. All four steroids preferentially sorbed to the clay and colloids in the silty loam sediment at the lowest aqueous concentration (1 ng/L) and as aqueous concentration increased, the distribution of sorbed steroid was similar to the distribution by weight of each size fraction within the whole sediment. In the sandy sediment, preferential sorption to fine particles was observed.

  15. The effect of particle size on sorption of estrogens, androgens and progestagens in aquatic sediment

    International Nuclear Information System (INIS)

    Sangster, Jodi L.; Oke, Hugues; Zhang, Yun; Bartelt-Hunt, Shannon L.

    2015-01-01

    Highlights: • Two sediments were used to evaluate the effects of particle size on steroid sorption. • Sorption capacity did not increase with decreasing particle size for all steroids. • Particle interactions affect the distribution of steroids within the whole sediments. • Preferential sorption to fine particles was observed. - Abstract: There is growing concern about the biologic effects of steroid hormones in impacted waterways. There is increasing evidence of enhanced transport and biological effects stemming from steroid hormones associated with soils or sediments; however, there are limited studies evaluating how steroid hormone distribution between various particle sizes within whole sediments affects steroid fate. In this study, sorption of 17β-estradiol, estrone, progesterone, and testosterone was evaluated to different size fractions of two natural sediments, a silty loam and a sandy sediment, to determine the steroid sorption capacity to each fraction and distribution within the whole sediment. Sorption isotherms for all steroid hormones fit linear sorption models. Sorption capacity was influenced more by organic carbon content than particle size. Interactions between size fractions were found to affect the distribution of steroids within the whole sediments. All four steroids preferentially sorbed to the clay and colloids in the silty loam sediment at the lowest aqueous concentration (1 ng/L) and as aqueous concentration increased, the distribution of sorbed steroid was similar to the distribution by weight of each size fraction within the whole sediment. In the sandy sediment, preferential sorption to fine particles was observed.

  16. Fate of {sup 14}C-triclocarban in biosolids-amended soils

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, Elizabeth Hodges, E-mail: lizah@ufl.edu [Soil and Water Science Department, University of Florida, 408 Newell Hall, Gainesville, Florida, 32611 (United States); Department of Health Sciences, University of Alaska Anchorage, DPL 404, 3211 Providence Drive, Anchorage, AK 99508-4614 (United States); O' Connor, George A., E-mail: gao@ufl.edu [Soil and Water Science Department, P.O. Box 110510, University of Florida, Gainesville, FL 32611-01519 (United States); McAvoy, Drew C., E-mail: mcavoy.dc@pg.com [Environmental Safety Department, P.O. Box 538707, The Procter and Gamble Company, Cincinnati, OH, 45253-8707 (United States)

    2010-06-01

    Triclocarban (TCC) is an antibacterial compound commonly detected in biosolids at parts-per-million concentrations. Approximately half of the biosolids produced in the United States are land-applied, resulting in a systematic release of TCC into the soil environment. The extent of biosolids-borne TCC environmental transport and potential human/ecological exposures will be greatly affected by its bioavailability and the rate of degradation in amended soils. To investigate these factors, radiolabeled TCC ({sup 14}C-TCC) was incorporated into anaerobically digested biosolids, amended to two soils, and incubated under aerobic conditions. The evolution of {sup 14}CO2 (biodegradation) and changes in chemical extractability (bioavailability) was measured over time. Water extractable TCC over the study period was low and significantly decreased over the first 3 weeks of the study (from 14% to 4% in a fine sand soil and from 3 to < 1% in a silty clay loam soil). Mineralization (i.e. ultimate degradation), as measured by evolution of {sup 14}CO{sub 2}, was < 4% over 7.5 months. Methanol extracts of the amended soils were analyzed by radiolabel thin-layer chromatography (RAD-TLC), but no intermediate degradation products were detected. Approximately 20% and 50% of the radioactivity in the amended fine sand and silty clay loam soils, respectively, was converted to bound residue as measured by solids combustion. These results indicate that biosolids-borne TCC becomes less bioavailable over time and biodegrades at a very slow rate.

  17. Performance of Low-Volume Roads with Wearing Course Layer of Silty Sandy Soil Modified with Rice Husk Ash and Lime

    Energy Technology Data Exchange (ETDEWEB)

    Behak Katz, L.; Musso Laespiga, M.

    2016-07-01

    Rice husk ash (RHA) is a by-product of rice milling. Its use as soil stabilizer is a way to replace the final disposal with environmental benefit. However, RHA is not cementitious itself but when mixed with lime forms cements which improve the soil properties. A research of performance of a silty sandy soil modified with RHA and lime as wearing course layer of low-volume roads was conducted through two full-scale test sections with different pavements built in Artigas, northern Uruguay. The alkaline reactivity of RHA is low because the husk burning is not controlled. The soil-RHA-lime mix design was conducted according to the Thompson’s Method. The pavement test sections were monitored through deflection measures by Benkelman beam and observations of surface condition. The deflections decreased over time in both test sections due to the development of cementation of the study materials. After one year, the dust emission was reduced, the wet skid resistance of pavement surfaces improved and there was not rutting. The researched pavements have had a good performance under the existing traffic and environmental conditions, demonstrating that wearing course layer of silty sand modified with RHA and lime is an alternative to improve the condition of low-volume roads and to replace the final disposal of RHA, with environmental, social and economic benefits. (Author)

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

    Science.gov (United States)

    2016-07-01

    LOAM SOIL ECBC-TR-1388 Roman G. Kuperman Ronald T. Checkai Michael Simini Carlton T. Phillips RESEARCH AND TECHNOLOGY DIRECTORATE Richard M...plastic wrap was stretched over the top of each container and secured with a rubber band. Three pinholes were made in the plastic wrap to 6...172–178. Glover, J.; Levander, O.; Parizek, J.; Vouk, V. Selenium. In Handbook on the Toxicology of Metals; Friberg, L., Norberg, G.F., Vouk, V.B

  19. Measuring Static and Dynamic Properties of Frozen Silty Soils

    Energy Technology Data Exchange (ETDEWEB)

    Furnish, M.D.

    1998-09-30

    A mechanical characterization of frozen silty soils has been conducted to support computer modeling of penetrators. The soils were obtained from the Eilson AFB (Alaska) vicinity. Quasi-static testing with a multiaxial system in a cold room and intermediate strain rate testing with a split Hopkinson pressure bar were conducted. Maximum stresses achieved were slightly above 1 GPa, apparently limiting the observed behavior primarily to elastic compression and pore crushing phenomena. Lower temperatures seem to increase the strength of the material markedly, although not by a simple factor. Lower temperatures and higher strain rates increase the apparent Young's and bulk moduli as well (an increase of {approximately} a factor of two is observed for strain rate increasing from 0.001 s{sup {minus}1} to 800 s{sup {minus}1}). The strength also depends strongly on strain rate. Increasing the strain rate from 0.001 {sup {minus}1} to 0.07 {sup {minus}1} increases the strength by a factor of five to ten (to values of order 1 GPa). However,only a small increase in strength is seen as strain rate is increased to {approximately} 10{sup 2}--10{sup 3} s{sup {minus}1}. The reliability of the strength measurements at strain rates< 1 s{sup {minus}1} is decreased due to details of the experimental geometry, although general trends are observable. A recipe is provided for a simulant soil based on bentonite, sand, clay-rich soil and water to fit the {approximately} 6% air-filled porosity, density and water content of the Alaska soils, based on benchtop mixing and jacketed compression testing of candidate mixes.

  20. Crop uptake and leaching losses of 15N labelled fertilizer nitrogen in relation to waterlogging of clay and sandy loam soils

    International Nuclear Information System (INIS)

    Webster, C.P.; Belford, R.K.; Cannell, R.Q.

    1986-01-01

    Ammonium nitrate fertilizer, labelled with 15 N, was applied in spring to winter wheat growing in undisturbed monoliths of clay and sandy loam soil in lysimeters; the rates of application were respectively 95 and 102 kg N ha -1 in the spring of 1976 and 1975. Crops of winter wheat, oilseed rape, peas and barley grown in the following 5 or 6 years were treated with unlabelled nitrogen fertilizer at rates recommended for maximum yields. During each year of the experiments the lysimeters were divided into treatments which were either freely drained or subjected to periods of waterlogging. Another labelled nitrogen application was made in 1980 to a separate group of lysimeters with a clay soil and a winter wheat crop to study further the uptake of nitrogen fertilizer in relation to waterlogging. In the first growing season, shoots of the winter wheater at harvest contained 46 and 58% of the fertilizer nitrogen applied to the clay and sandy loam soils respectively. In the following year the crops contained a further 1-2% of the labelled fertilizer, and after 5 and 6 years the total recoveries of labelled fertilizer in the crops were 49 and 62% on the clay and sandy loam soils respectively. In the first winter after the labelled fertilizer was applied, less than 1% of the fertilizer was lost in the drainage water, and only about 2% of the total nitrogen (mainly nitrate) in the drainage water from both soils was derived from the fertilizer

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  3. The influence of land use and management on nitrogen leaching in two agricultural catchments in China and Denmark

    DEFF Research Database (Denmark)

    Manevski, Kiril

    The agriculture in both China and Denmark needs to reduce nitrogen (N) leaching from the crop root zone in order to maintain high-quality groundwater for drinking purposes and to reduce eutrophication of surface waters. However, N leaching is a process that is concurrent and interacting with many...... others in the agro-ecosystem, such as crop growth and N uptake, mineralization of soil organic N and field management practices. Thus, the aim of the Ph.D. study was to investigate, with the use of the physically-based DAISY agro-ecosystem model, crop growth, soil N and leaching processes from (i) maize......-winter wheat annual systems at different fertilizer N rates in the North China Plain (NCP, silty loam soil), China, and (ii) maize for silage systems differing in past cropping, intercropping and fertilizer N levels in central Jutland (sandy loam soil, JB4) and southern Jutland (coarse sandy soil JB1, Jyndevad...

  4. Migration of Co and Cs radionuclides through a loam soil column

    International Nuclear Information System (INIS)

    Syed Hakimi Sakuma bin Syed Ahmad; Shimooka, K.

    1990-01-01

    A soil column experiment was conducted to determine the migration of Co and Cs radionuclides through a loam soil. The different migration rates of the radionuclides at low and high concentrations were determined at pH 7. Retardation factor (Rf) both the radionuclides at low and high concentrations were determined by fitting adsorbed concentration distribution equations to observed values. The calculation shows that the Rf1=500 and Rf2=3 for Co at high and low concentrations, respectively. For Cs, the Rf1=600 and Rf2=5 at high and low concentrations, respectively. The results shows that major portions of both the radionuclides were adsorbed onto the soil layer at the top by ion exchange mechanism which resulted in the high retardation factor values. Minor portions had migrated downwards as insoluble cations, pseudocolloids and very fine silt particles resulting in the low retardation factor

  5. Immobilization of Agricultural Phosphorus in an Illinois Floodplain Soil

    Science.gov (United States)

    Arenberg, M. R.; Arai, Y.

    2017-12-01

    Nutrient losses from the Mississippi watershed are exacerbating the growth of the hypoxic zone in the Gulf of Mexico. Located within the highly agricultural Piatt County, IL, Allerton Park encompasses a riparian forest that receives an influx of phosphorus (P) via surface runoff and leaching during spring flooding. The purpose of this study is to investigate the ability of a poorly drained Sawmill silty clay loam (fine-silty, mixed, superactive, mesic Cumulic Endoaquolls) and a poorly drained Tice silty clay loam (fine-silty, mixed, superactive, mesic Fluvaquentic Hapludolls), both with an average pH of 7.08, to buffer agricultural P losses through immobilization. If P is effectively sequestered, it may also lead to improved tree growth in woody biomass. The system's response to the seasonal flooding event was assessed by comparing P mineralization-immobilization dynamics within the bottomland and surrounding upland of the forest. Specifically, organic P, microbial P, phosphatase activity, and total P were assessed. First, total P ranged from 338 to 819 mg kg-1, averaging at 580 mg kg-1, in the bottomland and from 113 to 370 mg kg-1, averaging at 245 mg kg-1, in the upland. Next, organic P spanned from 90 to 457 mg kg-1in the bottomland, comprising an average of 45% of total P, and ranged from 42 to 191 mg kg-1in the upland, comprising an average of 36% of total P. Furthermore, microbial P averaged 13.08 mg kg-1 in the bottomland and 6.87 mg kg-1 in the upland. Finally, acidic phosphatase activity averaged 13 μmol p-nitrophenyl phosphate (PNP)/g·hr in the bottomland and 11 μmol PNP/g·hr in the upland while alkaline phosphatase activity averaged 24 μmol PNP/g·hr in the bottomland and 8 μmol PNP/g·hr in the upland. Our preliminary assessment suggests that the concentrations of total P, organic P, and microbial P in the bottomland are greater than that of the upland. This suggests that the floodplain has been effectively immobilizing agricultural P. This

  6. Geoelectrical Soil Properties of Farmlands Located on Ancient River Floodplains in EL Paso County Texas

    Science.gov (United States)

    Pegues, J. G.; Kaip, G.; Doser, D. I.

    2013-12-01

    Farming in Rio Grande flood plain deposit soils has presented challenges concerning soil salinity, soil drainage and soil collapse. Typical soil forms include Saneli silted clay loam, Harkey loam, Harkey silky loam clay and Tigua silty clay. In the lower valley farmlands of Socorro, TX, cotton and alfalfa are the principal crops, but grain sorghum, corn and vegetable crops also are suitable. Pecan trees, as well as fruit trees suited to the climate, can be grown. Agrarians are faced with varying results of crop yields over relatively small stretches of land; for example, a 22 acre area can contain multiple soil inclusions. This study was conducted on a 22 acre tract of farmland which has recently undergone multiple geophysical testing analyses that include: magnetics, DC resistivity, gravity, and ground penetrating radar. Results will compare flood plain sedimentation qualities to agricultural soil classes through the identification of soil salinity and grain size. This investigation will focus on the testing of geo-electrical soil properties through resistivity assessment. Examination of the sight using a capacity coupled resistivity meter to measure the soil properties over various time periods will be conducted. The results will be compared with the other geophysical data to look for correlations that highlight soil properties.

  7. Determination of heavy metal content and physico-chemical properties of soils in the vicinity of Tasik Chini, Pahang

    International Nuclear Information System (INIS)

    Sahibin Abdul Rahim; Muhd Barzani Gasim; Mohd Nizam Mohd Said; Wan Mohd Razi Idris; Azman Hashim; Sharilnizam Yusof; Masniyana Jamil

    2008-01-01

    This study was carried out to determine heavy metal content and physico-chemical properties of soils influencing heavy metal accumulation in some series surrounding the Chini Lakes. A total of 15 topsoil sample were collected randomly from 6 stations. The physical properties that were analyzed include particle size distribution and soil organic matter. Meanwhile, the chemical characteristics determined were pH, electrical conductivity and cation exchange capacity. It was found that heavy metal content of Cd, Cr, Cu, Co, Pb, Zn and Mn were low whereas Fe content was high. The textures of soil studied were clay, loamy sand, sandy loam, clay loam and silty clay loam. The mean of organic matter ranged from 2.68 to 11.46 %. The soil pH showed that the soil studied was acidic with values ranged between 3.36 to 3.72. The range of electrical conductivity mean was between 2150 μScm -1 to 2403 μScm -1 . Cation exchange capacity mean ranged from 2.85 until 8.59 cmol/ kg. Correlation analysis showed that there were positive and negative significant correlations between soils parameters heavy metal concentration. Analysis of variance (ANOVA) showed that there were significant differences in organic matter percentage, pH, cation exchange capacity and heavy metals except cadmium between sampling station. (author)

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

    Science.gov (United States)

    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.

  9. Neutron Gauge Calibration Curve as Affected by Chloride Concentration and Bulk Density of Loam Soil

    International Nuclear Information System (INIS)

    AL-Hasani, A.A.; Fahad, A.A.; Shihab, R.M.

    2010-01-01

    chloride concentration and bulk density are considered among important factors affecting calibration curve of neutron gauge in the soil.The aim of this study was to investigate the effect of chloride concentration and bulk density of a loam soil on neutron gauge calibration curve.Sufficient amount of loam soil was air dried screened through a 2 mm sieve,and divided into three equal portions.Sodium chloride of 2.5 and 6.6g kg'-1 soil was added to the first and second portions,respectively.The third portion was left as a control.The soil then moistened and mixed well to make volumetric water content within the range of 0.01 to 0.24 cm 3 cm - 3. The moist soil was packed into an iron drum 0.80 m diameter and 1.00 m height to obtain bulk densities of 1.10 and 1.30 to 1.60 Mg m - 3 for uncompacted soil,respectively.Access tube 0.05 m inner diameter was installed in the center of the drum.Three readings from CPN 503 neutron gauge were taken at each 0.15,0.30, 0.45,and 0.75 m depth.Results indicated that the count (counts/standard count) for an aqueous solution decreased with the increase in chloride concentration.Similarly, the slope of the linear calibration curves of the investigated soil decreased with the increase in chloride concentration.Shifting of the curves was 9 to 10%for the uncompacted soil, whereas it was 12 to 14 % for the compacted of low and high concentration of chloride, respectively . Results of changing bulk density always reduced the slope value as compared with the uncorrected count ratio.

  10. THE EFFECT OF SALINITY-SODICITY AND GLYPHOSATE FORMULATIONS – AVANS PREMIUM 360 SL ON PHOSPHOMONOESTERASE ACTIVITIES IN SANDY LOAM

    Directory of Open Access Journals (Sweden)

    Maciej Płatkowski

    2016-01-01

    Full Text Available The aim of study was to determine the influence of NaCl and glyphosate-based herbicide Avans Premium 360 SL on acid and alkaline phosphomonoesterase activities in sandy loam. The experiment was carried out in laboratory conditions on sandy loam with Corg content 10.90 g/kg. Soil was divided into half kilogram samples and adjusted to 60% of maximum water holding capacity. In the experiment dependent variables were: I – dosages of Avans Premium 360 SL (0, a recommended field dosage – FD, a tenfold higher dosage – 10 FD and hundredfold higher dosage – 100 FD, II – amount of NaCl (0, 3% and 6%, III – day of experiment (1, 7, 14, 28 and 56. On days of experiment the activity of alkaline and acid phosphomonoesterase activity was assayed spectrophotometrically. The obtained result showed that the application of Avans Premium 360 SL decreased in acid and alkaline phosphomonoesterase activity in clay soil. Significant interaction effect between the dosage of Avans Premium 360 SL, NaCl amount and day of experiment was reported in the experiment. The inhibitory effect of Avans Premium 360 SL was the highest in soil with NaCl at the amount of 6%.

  11. Impact of industrial effluent on growth and yield of rice (Oryza sativa L.) in silty clay loam soil.

    Science.gov (United States)

    Anwar Hossain, Mohammad; Rahman, Golum Kibria Muhammad Mustafizur; Rahman, Mohammad Mizanur; Molla, Abul Hossain; Mostafizur Rahman, Mohammad; Khabir Uddin, Mohammad

    2015-04-01

    Degradation of soil and water from discharge of untreated industrial effluent is alarming in Bangladesh. Therefore, buildup of heavy metals in soil from contaminated effluent, their entry into the food chain and effects on rice yield were quantified in a pot experiment. The treatments were comprised of 0, 25%, 50%, 75% and 100% industrial effluents applied as irrigation water. Effluents, initial soil, different parts of rice plants and post-harvest pot soil were analyzed for various elements, including heavy metals. Application of elevated levels of effluent contributed to increased heavy metals in pot soils and rice roots due to translocation effects, which were transferred to rice straw and grain. The results indicated that heavy metal toxicity may develop in soil because of contaminated effluent application. Heavy metals are not biodegradable, rather they accumulate in soils, and transfer of these metals from effluent to soil and plant cells was found to reduce the growth and development of rice plants and thereby contributed to lower yield. Moreover, a higher concentration of effluent caused heavy metal toxicity as well as reduction of growth and yield of rice, and in the long run a more aggravated situation may threaten human lives, which emphasizes the obligatory adoption of effluent treatment before its release to the environment, and regular monitoring by government agencies needs to be ensured. Copyright © 2015. Published by Elsevier B.V.

  12. Lysimeter experiments to determine the ability of soil to reduce concentrations of BOD, available P and inorganic N in dirty water.

    Science.gov (United States)

    Brookman, S K E; Chadwick; Retter, A R

    2005-11-01

    Lysimeter experiments were conducted to determine the ability of different soils to reduce levels of biochemical oxygen demand (BOD) and concentrations of molybdate reactive phosphorus (MRP) and ammonium-N (NH4(+)-N) in dirty water and the impact of applications on nitrate leaching. An additional experiment investigated the effect of dirty water components on leaching quality. This information is required to assess the potential risk of dirty water applications on polluting groundwater and to assess the use of such soils in the development of treatment systems for dirty water. Intact and disturbed soil lysimeters, 0.5 and 1m deep were constructed from four soils; a coarse free-draining sandy loam, a sandy loam over soft sandstone, a calcareous silty clay over chalk and a sandy loam over granite. For the coarse free-draining sandy loam, lysimeters were also constructed from disturbed soil with and without the addition of lime, to assess if this could increase phosphorus immobilisation. Levels of BOD and concentrations of MRP, NH4(+)-N and nitrate (NO3(-)-N) of leachates were measured following dirty water applications at 2 and 8 mm day(-1) under laboratory conditions. Under the daily 2mm application, all soils were effective at treating dirty water, reducing concentrations of BOD, MRP and NH4(+)- N by > or = 98% but NO3(-)-N concentrations increased up to 80 mg l(-1) from the 0.5 m deep lysimeters of the sandy loam over granite. Soils were less effective at reducing levels of BOD, MRP and NH4(+)- N at the 8 mm daily rate of application, with maximum NO3(-)-N concentrations of leachates of 200 mg l(-1) from disturbed soils.

  13. Weeds of cereal stubble-fields on various soils in the Kielce region. P. 1. Podzolic and brown soils developed from sands and loams

    Directory of Open Access Journals (Sweden)

    Franciszek Pawłowski

    2013-12-01

    Full Text Available Occupying cereal stubble-fields weed flora is the most characteristic of the environmental (especially soil conditions. Because of its developing and accomplishing the reproductive stages there it can threatens cultivated plants. They are considered to complete the seed store in a soil by 393 min per ha. The results presented in the paper concern the species composition, number and constancy (S and indice of coverage (D of the cereal stubble-field weed species on various soils in the Kielce region (the central part of Poland. The report was based upon 885 phytosociological records collected in the 268 stands. The records were carried out after the crop harvest, in the latter part of September, in 1976-1980. Soil were chosen on the base of soil maps. The analyse of soil samples, taken at the investigation process, were done in order to confirm the soil quality. The worked out material was divided into three parts. The first part, including 369 phytosociological records collected in the 112 stands (in 90 localities concerns stubble-field weeds on podzolic and brown soils developed from sands (loose, weakly loamy and loamy and loams (light and medium. It was found that these soils were grown by 108 (loamy sands to 132 (weakly loamy sands weed species. Among them 66 species were common for all of the soils. Species composition was not differentiated by the soil type (brown, podzolic within kind of the. soil (sand or loams. Among soil examined, the brown loams was the most abundant with species of high constancy degree (30 species but brown loose sands and podzolic loamy sands was the poorest one with (16 species.

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

    Science.gov (United States)

    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

  15. Degradation of roxarsone in a silt loam soil and its toxicity assessment.

    Science.gov (United States)

    Liang, Tengfang; Ke, Zhengchen; Chen, Qing; Liu, Li; Chen, Guowei

    2014-10-01

    The land application of poultry or swine litter, containing large amounts of roxarsone, causes serious arsenic pollution in soil. Understanding biotransformation process of roxarsone and its potential risks favors proper disposal of roxarsone-contaminated animal litter, yet remains not achieved. We report an experimental study of biotransformation process of roxarsone in a silt loam soil under various soil moisture and temperature conditions, and the toxicity of roxarsone and its products from degradation. Results showed that soil moisture and higher temperature promoted roxarsone degradation, associating with emergent pentavalent arsenic. Analysis of fluorescein diacetate (FDA) hydrolysis activity revealed that roxarsone does not exert acute toxic on soil microbes. With the release of inorganic arsenic, FDA hydrolysis activity was inhibited gradually, as evidenced by ecotoxicological assessment using Photobacterium leiognathi. The results shade new lights on the dynamic roxarsone biotransformation processes in soil, which is important for guiding appropriate disposal of poultry or swine litter in the environment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. The Effect of Compost and the Ripe Fruit Waste of Fig on some Physical Properties of Surface Soil

    Directory of Open Access Journals (Sweden)

    zahra dianat maharluei

    2017-02-01

    Full Text Available Introduction: In arid and semi-arid soils, low organic matter is one of the barriers to achieving optimal performance. The soils with more organic matter have a better structure and are more resistant to erosive factors such as water and wind. Soil organic matter has a particular importance and has significant impact on the stability of soil aggregates, the extension of plant root system, carbon and water cycles and soil resistance to erosion. This substance acts as a cementing agent and plays an important role in soil flocculation and formation of resistant aggregates.Also, the addition of organic matter to the soil increases soil porosity and decreases soil bulk density. Materials and Methods: In this research, the effect of the two types of organic matter (compost and the ripe fruit waste of fig on some soil physical properties was studied. A factorial experiment based on completely randomized design, including the four levels of compost and the ripe fruit waste of fig (0, 1, 2 and 4 by weight % and three soil types (loamy sand, loam and silty clay loam with three replications was carried out. The soil samples were collected from the three territories of Fars Province: loamy sand soil from Shiraz, loamy soil from Maharlu and Silty clay loam soil from Zarghan area. The soil samples were air dried and passed through a 2 mm sieve. The physical properties including the bulk density, particle density, porosity, moisture content and soil crust strength was measured. In this research, the soil texture by hydrometer method, Electrical conductivity of the soil saturated paste extract by electrical conductivity meter, saturated paste pH by pH meter, seedling emergence test, soil crust strength by a pocket penetrometer (HUMBOLDT MFG.CO. bulk density by cylindrical sample and particle density by pycnometer method were measured. The fig fruit treatments were prepared by thoroughly mixing the dried powder of ripe fig fruit passed through a 2 mm sieve (with

  17. Use of INAA in the preparation of a set soil Reference Materials with certified values of total element contents

    International Nuclear Information System (INIS)

    Kucera, J.; Horakova, J.; Soukal, L.

    1997-01-01

    A set of certified Reference Materials was prepared consisting of four natural agricultural soils with normal (n) and elevated (e) levels of element contents: CRM 7001 Light Sandy Soil (n), CRM 7002 Light Sandy Soil (e), CRM 7003 Silty Clay Loam (n), and CRM 7004 Loam (e). In these materials, certified and/or information values of the total contents of the elements As, Ba, Be, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, V and Zn, and their fractions extractable by aqua regia, boiling and cold 2M nitric acid were derived from an interlaboratory comparison in which 28 laboratories participated. Highly precise and accurate procedures of instrumental neutron activation analysis (INAA) were employed for homogeneity testing and also for certification of the total element contents. For comparation purposes, NIST SRM-2704 Buffalo River Sediment was analyzed by INAA, as well. The INAA results obtained compared very well with the certified and/or information values for four soil CRMs and also with NIST values for SRM-2704. From this agreement, a very high reliability of the new soil CRMs can be inferred. (author)

  18. Influence of Long-term Application of Feedlot Manure Amendments on Water Repellency of a Clay Loam Soil.

    Science.gov (United States)

    Miller, Jim J; Beasley, Bruce W; Hazendonk, Paul; Drury, Craig F; Chanasyk, David S

    2017-05-01

    Long-term application of feedlot manure to cropland may increase the quantity of soil organic carbon (C) and change its quality, which may influence soil water repellency. The objective was to determine the influence of feedlot manure type (stockpiled vs. composted), bedding material (straw [ST] vs. woodchips [WD]), and application rate (13, 39, or 77 Mg ha) on repellency of a clay loam soil after 17 annual applications. The repellency was determined on all 14 treatments using the water repellency index ( index), the water drop penetration time (WDPT) method, and molarity of ethanol (MED) test. The C composition of particulate organic matter in soil of five selected treatments after 16 annual applications was also determined using C nuclear magnetic resonance-direct polarization with magic-angle spinning (NMR-DPMAS). Manure type had no significant ( > 0.05) effect on index and WDPT, and MED classification was similar. Mean index and WDPT values were significantly greater and MED classification more hydrophobic for WD than ST. Application rate had no effect on the index, but WDPT was significantly greater and MED classification more hydrophobic with increasing application rate. Strong ( > 0.7) but nonsignificant positive correlations were found between index and WDPT versus hydrophobic (alkyl + aromatic) C, lignin at 74 ppm (O-alkyl), and unspecified aromatic compounds at 144 ppm. Specific aromatic compounds also contributed more to repellency than alkyl, O-alkyl, and carbonyl compounds. Overall, all three methods consistently showed that repellency was greater for WD- than ST-amended clay loam soil, but manure type had no effect. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  19. The fate of fresh and stored 15N-labelled sheep urine and urea applied to a sandy and a sandy loam soil using different application strategies

    DEFF Research Database (Denmark)

    Sørensen, P.; Jensen, E.S.

    1996-01-01

    The fate of nitrogen from N-15-labelled sheep urine and urea applied to two soils was studied under field conditions. Labelled and stored urine equivalent to 204 kg N ha(-1) was either incorporated in soil or applied to the soil surface prior to sowing of Italian ryegrass (Lolium multiflorum L...... and soil was not significantly different for incorporated urine and urea. Almost all the supplied labelled N was accounted for in soil and herbage in the sandy loam soil, whereas 33-34% of the labelled N was unaccounted for in the sandy soil. When the stored urine was applied to the soil surface, 20...... was applied to growing ryegrass at the sandy loam soil, the immobilization of urine-derived N was significantly reduced compared to application prior to sowing. The results indicated that the net mineralization of urine N was similar to that of urea in the sandy soil, but only about 75% of the urine N was net...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  2. Cultivos de cobertura: efectos sobre la macroporosidad y la estabilidad estructural de un suelo franco-limoso Cover crops: effects on soil macroporosity and soil structural stability in a silt loam soil

    Directory of Open Access Journals (Sweden)

    María Florencia Varela

    2011-07-01

    Full Text Available Los suelos franco-limosos manejados con siembra directa a menudo poseen porosidad estructural baja e inestable. Con el objetivo de determinar la capacidad de los cultivos de cobertura (CC de mejorar la porosidad y estabilidad estructural de estos suelos se llevaron a cabo experimentos de campo y de invernáculo. Ambos tuvieron tratamientos con y sin CC (avena, Avena sativa L., en rotación con soja (Glicine max L. Merr.. Luego de los CC se midieron densidad aparente (DA, el índice de inestabilidad estructural (IE y en el ensayo de invernáculo además, se midió la evolución de la distribución de tamaño de poros (DTP. En ambos ensayos la introducción de CC no disminuyó la DA, aunque incrementó la estabilidad del suelo (PNo- till (NT silt loam topsoils have often a low and unstable structural porosity. The objective of this study was to determine the capability of cover crops (CC of improving the structural porosity and stability of silt loam soils under NT. Greenhouse and field experiments were carried out on a silt loam soil (Typic Argiudoll with and without CC (oat, Avena sativa L. in crop sequences with soybean (Glicine max L. Merr.. Soil bulk density (DA and aggregate instability index (IE were measured after the CC in both experiments. In the greenhouse experiment, soil pore size distribution (DTP was measured. The use of CC did not change DA, but soil IE was significantly lower in crop sequences with CC (P < 0.05 both under field and greenhouse conditions. Stability increases were likely due to the effect of CC residues and root mass. No differences in DTP were found between treatments, although a significant effect of sampling date was observed (P<0.05. Changes in DTP were due to significant increases in mesopore (517.5% and macropore (52.7% volumes. Such changes occurred in all the treatments, probably due to the soil wetting-drying cycles. The results found in this study agree with other studies carried out on silt loams in the

  3. Calibration, field-testing, and error analysis of a gamma-ray probe for in situ measurement of dry bulk density

    International Nuclear Information System (INIS)

    Bertuzzi, P.; Bruckler, L.; Gabilly, Y.; Gaudu, J.C.

    1987-01-01

    This paper describes a new gamma-ray probe for measuring dry bulk density in the field. This equipment can be used with three different tube spacings (15, 20 and 30 cm). Calibration procedures and local error analyses are proposed for two cases: (1) for the case where the access tubes are parallel, calibration equations are given for three tube spacings. The linear correlation coefficient obtained in the laboratory is satisfactory (0.999), and a local error analysis shows that the standard deviation in the measured dry bulk density is small (+/- 0.02 g/cm 3 ); (2) when the access tubes are not parallel, a new calibration procedure is presented that accounts for and corrects measurement bias due to the deviating probe spacing. The standard deviation associated with the measured dry bulk density is greater (+/- 0.05 g/cm 3 ), but the measurements themselves are regarded as unbiased. After comparisons of core samplings and gamma-ray probe measurements, a field validation of the gamma-ray measurements is presented. Field validation was carried out on a variety of soils (clay, clay loam, loam, and silty clay loam), using gravimetric water contents that varied from 0.11 0.27 and dry bulk densities ranging from 1.30-1.80 g°cm -3 . Finally, an example of dry bulk density field variability is shown, and the spatial variability is analyzed in regard to the measurement errors

  4. 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.

    Science.gov (United States)

    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.

  5. Evaluation of soil fertility status of Regional Agricultural Research Station, Tarahara, Sunsari, Nepal

    Directory of Open Access Journals (Sweden)

    Dinesh Khadka

    2017-10-01

    Full Text Available Soil fertility evaluation of an area or region is most basic decision making tool for the sustainable soil nutrient management. In order to evaluate the soil fertility status of the Regional Agricultural Research Station (RARS, Tarahara, Susari, Nepal. Using soil sampling auger 81 soil samples (0-20 cm were collected based on the variability of land. The collected samples were analyzed for their texture, structure, colour, pH, OM, N, P2O5, K2O, Ca, Mg, S, B, Fe, Zn, Cu and Mn status. The Arc-GIS 10.1 software was used for the preparation of soil fertility maps. The soil structure was granular to sub-angular blocky and varied between brown- dark grayish brown and dark gray in colour. The sand, silt and clay content were 30.32±1.4%, 48.92±0.89% and 20.76±0.92%, respectively and categorized as loam, clay loam, sandy loam, silt loam and silty clay loam in texture. The soil was moderately acidic in pH (5.98±0.08. The available sulphur (2.15±0.21 ppm, available boron (0.08±0.01 ppm and available zinc (0.35±0.03 ppm status were very low, whereas extractable magnesium (44.33±6.03 ppm showed low status. Similarly, organic matter (2.80±0.07%, total nitrogen (0.09±0.004 %, extractable calcium (1827.90±45.80 ppm and available copper (1.15±0.04 ppm were medium in content. The available phosphorus (39.77±5.27 ppm, extractable potassium (134.12±4.91 ppm, and available manganese (18.15±1.15 ppm exhibits high status, while available iron (244.7±19.70 ppm was very high. The fertilizer recommendation can be done based on determined soil fertility status to economize crop production. Furthermore, research farm should develop future research strategy accordance with the prepared soil data base.

  6. Heavy metal phytoextraction-natural and EDTA-assisted remediation of contaminated calcareous soils by sorghum and oat.

    Science.gov (United States)

    Mahmood-Ul-Hassan, Muhammad; Suthar, Vishandas; Ahmad, Rizwan; Yousra, Munazza

    2017-10-30

    The abilities of sorghum (Sorghum bicolor L.) and oat (Avena sativa L.) to take up heavy metals from soils amended with ethylenediaminetetraacetic acid (EDTA) were assessed under greenhouse conditions. Both plants were grown in two soils contaminated with heavy metals (Gujranwala-silty loam and Pacca-clay loam). The soils were treated with 0, 0.625, 1.25, and 2.5 mM EDTA kg -1 soil applied at both 45 and 60 days after sowing (DAS); the experiment was terminated at 75 DAS. Addition of EDTA significantly increased concentrations of Cd, Cr, and Pb in roots and shoots, and bio-concentration factors and phytoextraction rates were also increased. Post-harvest soil analysis showed that soluble fractions of metals were also increased significantly. The increase in Cd was ≈ 3-fold and Pb was ≈ 15-fold at the highest addition of EDTA in Gujranwala soil; in the Pacca soil, the increase was less. Similarly, other phytoremediation factors, such as metal translocation, bio-concentration factor, and phytoextraction, efficiency were also maximum when soils were treated with 2.5 mM EDTA kg -1 soil. The study demonstrated that sorghum was better than oat for phytoremediation.

  7. Late-Pleistocene evolution of the East Mediterranean shallow continental shelf of north-central Israel

    Science.gov (United States)

    Shtienberg, Gilad; Dix, Justin; Waldmann, Nicolas; Makovsky, Yizhaq; Bookman, Revital; Roskin, Joel; Bialik, Or; Golan, Arik; Sivan, Dorit

    2016-04-01

    Sea-level fluctuations are a dominant and dynamic mechanism that control coastal environmental through time. This is especially the case for the successive regressions and transgressions over the last interglacial cycle, which have shaped the deposition, preservation and erosion patterns of unconsolidated sediments currently submerged on continental shelves. The current study focuses on an integrated high-resolution marine and terrestrial litho-stratigraphic and geophysical framework of the north-central Mediterranean coastal zone of Israel. The interpretation enabled the reconstruction of the coastal evolution over the last ˜130 ka. A multi-disciplinary approach was applied by compiling existing elevation raster grids, bathymetric charts, detailed lithological borehole data-sets, a dense 110 km long sub-bottom geophysical survey and seven continuous boreholes sediment records. Based on seismic stratigraphic analysis, observed geometries, and reflective appearances, six bounding surfaces and seven seismic units were identified and characterized. Meanwhile, the chronostratigraphy of the terrestrial side was constructed through integration of magnetic susceptibility, sedimentological and geochemical analysis with 17 new OSL ages. The seismic units were correlated with the available terrestrial borehole data and then associated to the retrieved terrestrial chronostratigraphy to produce a 4D reconstruction model of the paleo-landscape. The entire unconsolidated sequence overlies a calcareous aeolianite (locally named Kurkar unit) dated from ˜131 - ˜104 ka, which represents the top of the last interglacial cycle dune sediments. The lower unconsolidated unit consists of a red silty loam dated to ˜71 ka. This Red-Paleosol unit is overlaid by a dark brown clayey silty loam This Brown-Paleosol unit dates to ˜58 - ˜36 ka and is overlaid by a dark silty clay wetland deposit dated to ˜21 - ˜10 ka. The wetland unit is topped by a quartz sand dated to ˜6.6 - 0.1 ka

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

    Science.gov (United States)

    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.

  9. Direct and Indirect Short-term Effects of Biochar on Physical Characteristics of an Arable Sandy Loam

    DEFF Research Database (Denmark)

    Sun, Zhencai; Moldrup, Per; Elsgaard, Lars

    2013-01-01

    Biochar addition to agricultural soil is reported in several studies to reduce climate gas emissions, boost carbon storage, and improve soil fertility and crop productivity. These effects may be partly related to soil physical changes resulting from biochar amendment, but knowledge of how biochar...... application mechanistically affects soil physical characteristics is limited. This study investigated the effect of biochar application on soil structural and functional properties, including specific surface area, water retention, and gas transport parameters. Intact soil cores were taken from a field...... experiment on an arable sandy loam that included four reference plots without biochar and four plots with 20 tons ha(-1) biochar incorporated into the upper 20 cm 7 months before sampling. Water retention was measured at matric potentials ranging from wet (pF 1.0) to extremely dry conditions (pF similar to 6...

  10. Effect of biochar on aerobic processes, enzyme activity, and crop yields in two sandy loam soils

    DEFF Research Database (Denmark)

    Sun, Zhencai; Bruun, Esben; Arthur, Emmanuel

    2014-01-01

    Biochar added to agricultural soils may sequester carbon and improve physico-chemical conditions for crop growth, due to effects such as increased water and nutrient retention in the root zone. The effects of biochar on soil microbiological properties are less certain. We addressed the effects...... of wood-based biochar on soil respiration, water contents, potential ammonia oxidation (PAO), arylsulfatase activity (ASA), and crop yields at two temperate sandy loam soils under realistic field conditions. In situ soil respiration, PAO, and ASA were not significantly different in quadruplicate field...... plots with or without biochar (20 Mg ha−1); however, in the same plots, volumetric water contents increased by 7.5 % due to biochar (P = 0.007). Crop yields (oat) were not significantly different in the first year after biochar application, but in the second year, total yields of spring barley increased...

  11. Net sulfur mineralization potential in Swedish arable soils in relation to long-term treatment history and soil properties

    DEFF Research Database (Denmark)

    Boye, Kristin; Nilsson, S Ingvar; Eriksen, Jørgen

    2009-01-01

    accumulated net S mineralization (SAccMin) and a number of soil physical and chemical properties were determined. Treatments and soil differences in SAccMin, as well as correlations with soil variables, were tested with single and multivariate analyses. Long-term FYM application resulted in a significantly (p......The long-term treatment effect (since 1957-1966) of farmyard manure (FYM) application compared with crop residue incorporation was investigated in five soils (sandy loam to silty clay) with regards to the net sulfur (S) mineralization potential. An open incubation technique was used to determine...... = 0.012) higher net S mineralization potential, although total amounts of C, N, and S were not significantly (p soils within this treatment. The measured soil variables were not significantly correlated...

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

    Science.gov (United States)

    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; Pcharacteristics 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.

  13. Soil nitrogen dynamics and Capsicum Annuum sp. plant response to biochar amendment in silt loam soil

    Science.gov (United States)

    Horel, Agota; Gelybo, Gyorgyi; Dencso, Marton; Toth, Eszter; Farkas, Csilla; Kasa, Ilona; Pokovai, Klara

    2017-04-01

    The present study investigated the growth of Capsicum Annuum sp. (pepper) in small-scale experiment to observe changes in plant growth and health as reflected by leaf area, plant height, yield, root density, and nitrogen usage. Based on field conditions, part of the study aimed to examine the photosynthetic and photochemical responses of plants to treatments resulting from different plant growth rates. During the 12.5 week long study, four treatments were investigated with biochar amount of 0, 0.5%, 2.5%, and 5.0% (by weight) added to silt loam soil. The plants were placed under natural environmental conditions, such that photosynthetic activities from photosynthetically active radiation (PAR) and the plants photochemical reflectance index (PRI) could be continuously measured after exposure to sunlight. In this study we found that benefits from biochar addition to silt loam soil most distinguishable occurred in the BC2.5 treatments, where the highest plant yield, highest root density, and highest leaf areas were observed compared to other treatments. Furthermore, data showed that too low (0.5%) or too high (5.0%) biochar addition to the soil had diminishing effects on Capsicum Annuum sp. growth and yield over time. At the end of the 12th week, BC2.5 had 22.2%, while BC0.5 and BC5.0 showed 17.4% and 15.7% increase in yield dry weight respectively compared to controls. The collected data also showed that the PRI values of plants growing on biochar treated soils were generally lower compared to control treatments, which could relate to leaf nitrogen levels. Total nitrogen amount showed marginal changes over time in all treatments. The total nitrogen concentration showed 28.6% and 17.7% increase after the 6th week of the experiment for BC2.5 and BC5.0, respectively, while inorganic nutrients of NO3-N and NH4+-N showed a continuous decrease during the course of the study, with a substantial drop during the first few weeks. The present study provides evidence for impact

  14. 振冲碎石桩加固高层建筑粉砂土地基实例分析%Case Study on Improving Silty Sand Foundation of Tall Building by Vibro-replacement Stone Column

    Institute of Scientific and Technical Information of China (English)

    谢新宇; 应宏伟; 夏建中

    2001-01-01

    In this paper, the case studies of two tall buildings built on silty sand improved by vibro-replacement stone column in Hangzhou are reported. The design and computation method for vibro-replacement stone column composite foundation are introduced. Based on field testing results,the construction techniques of vibro-replacement stone column and the appraisement of improvement effect are discussed. It is the first time that the vibro-replacement stone column method has been successfully applied to improve silty sand foundation of tall building in Hangzhou.%本文介绍杭州两座高层建筑物采用振冲碎石桩加固粉砂土地基的工程实例。结合有关现场测试成果,探讨了高层建筑振冲碎石桩地基设计计算、振冲碎石桩施工控制和加固效果评价等有关问题。为振冲碎石桩在同类地基中的推广应用提供一些成功经验。

  15. Inhibition effect of zinc in wastewater on the N2O emission from coastal loam soils.

    Science.gov (United States)

    Huang, Yan; Ou, Danyun; Chen, Shunyang; Chen, Bin; Liu, Wenhua; Bai, Renao; Chen, Guangcheng

    2017-03-15

    The effects of zinc (Zn) on nitrous oxide (N 2 O) fluxes from coastal loam soil and the abundances of soil nitrifier and denitrifier were studied in a tidal microcosm receiving livestock wastewater with different Zn levels. Soil N 2 O emission significantly increased due to discharge of wastewater rich in ammonia (NH 4 + -N) while the continuous measurements of gas flux showed a durative reduction in N 2 O flux by high Zn input (40mgL -1 ) during the low tide period. Soil inorganic nitrogen concentrations increased at the end of the experiment and even more soil NH 4 + -N was measured in the high-Zn-level treatment, indicating an inhibition of ammonia oxidation by Zn input. Quantitative PCR of soil amoA, narG and nirK genes encoding ammonia monooxygenase, nitrate reductase and nitrite reductase, respectively, showed that the microbial abundances involved in these metabolisms were neither affected by wastewater discharge nor Zn contamination. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. ELASTOPLASTICIDAD DE UN SUELO FRANCO ARENOSO DE SABANA I SANDY LOAM SAVANNA SOIL ELASTOPLASTICITY

    Directory of Open Access Journals (Sweden)

    Américo Hossne García

    2018-04-01

    Full Text Available The knowledge of elastoplastic properties is important for calculating soil elastic and plastic deformations experienced by static or dynamic loads generated, for example, by farm implements and root growth. The objective of this study was to determine the soil elastoplastic parameters: Young’s modulus (E, the shear modulus (G, bulk modulus (K and Poisson’s ratio (υ of a sandy-loam soil from a savanna in Monagas State, Venezuela. Triaxial tests and regression analyses were used to interpret the variance between them. The results show that E varied from 4693.39 to 36669.35 kPa; G from 700 to 5000 kPa; K from 500 to 2000 kPa and υ had a value of 0.50. It is concluded that these soils are incompressible under plastic conditions, i.e. easily deformable. The Poisson’s ratio varied significantly with soil water content. The Young modulus, bulk modulus and the shear modulus showed high variation with respect to water content. Both the Young’s modulus and Poisson’s ratio increased, at low soil water content, with the rise in chamber pressure .

  17. Eleven years' effect of conservation practices for temperate sandy loams: II. Soil pore characteristics

    DEFF Research Database (Denmark)

    Abdollahi, Lotfallah; Munkholm, Lars Juhl

    2017-01-01

    Conservation agriculture (CA) is regarded by many as a sustainable intensification strategy. Minimal soil disturbance in combination with residue retention are important CA components. This study examined the long-term effects of crop rotation, residue retention, and tillage on soil pore characte......Conservation agriculture (CA) is regarded by many as a sustainable intensification strategy. Minimal soil disturbance in combination with residue retention are important CA components. This study examined the long-term effects of crop rotation, residue retention, and tillage on soil pore...... characteristics of two Danish sandy loams. Rotation R2 is a rotation of winter crops (mainly cereals) with residues retained, rotation R3 a mix of winter and spring crops (mainly cereals) with residues removed, and rotation R4 the same mix of winter and spring crops, but with residues retained. Each rotation...... included the tillage treatments: moldboard plowing to 20-cm depth (MP), harrowing to 8- to 10-cm depth (H) and direct drilling (D). Soil cores were taken from the topsoil (4–8, 12–16, 18–27 cm) in mid-autumn 2013 and early spring 2014. Water retention, air permeability, and gas diffusivity was determined...

  18. Effect of soil texture on phytoremediation of arsenic-contaminated soils

    Science.gov (United States)

    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

  19. Aggregate-associated carbon and nitrogen in reclaimed sandy loam soils

    Energy Technology Data Exchange (ETDEWEB)

    Wick, A.F.; Stahl, P.D.; Ingram, L.J. [Virginia Polytechnic Institute & State University, Blacksburg, VA (United States)

    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 soils (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.

  20. Surface Runoff of Pesticides from a Clay Loam Field in Sweden.

    Science.gov (United States)

    Larsbo, Mats; Sandin, Maria; Jarvis, Nick; Etana, Ararso; Kreuger, Jenny

    2016-07-01

    Pesticides stored at or close to the soil surface after field application can be mobilized and transported off the field when surface runoff occurs. The objective of our study was to quantify the potential pesticide losses in surface runoff from a conventionally managed agricultural field in a Swedish climate. This was achieved by measuring surface runoff volumes and concentrations in runoff of six spring-applied pesticides and autumn-applied glyphosate and its metabolite aminomethylphosphonic acid (AMPA). Measurements were performed for 3 yr both during the growing seasons and during intervening winter snowmelt periods on a clay loam field close to Uppsala. During growing seasons, surface runoff was generated on only five occasions during one 25-d period in 2012 when the infiltration capacity of the soil may have been reduced by structural degradation due to large cumulative rainfall amounts after harrowing. Concentrations in surface runoff exceeded Swedish water quality standards in all samples during this growing season for diflufenican and pirimicarb. Surface runoff was generated during three snowmelt periods during the winter of 2012-2013. All of the applied pesticides were found in snowmelt samples despite incorporation of residues by autumn plowing, degradation, and leaching into the soil profile during the period between spraying and sampling. Concentrations of glyphosate ranged from 0.12 to 7.4 μg L, and concentrations of AMPA ranged from 0 to 2.7 μg L. Our results indicate that temporal changes in hydraulic properties during the growing season and when the soil freezes during winter affect pesticide losses through surface runoff. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  1. The use of stable isotopes for Cr(VI) determination in silty-clay soil solution.

    Science.gov (United States)

    Zuliani, Tea; Sčančar, Janez; Milačič, Radmila

    2013-09-01

    In assessing the environmental hazard of Cr(VI) present in soil, exchangeable Cr(VI) is important, since it can be easily washed out from the upper part of the soil into subsurface soil, surface and ground water, and taken up by plants. The aim of this study was to evaluate the degree of species interconversion that may occur during the extraction of exchangeable Cr(VI) from silty-clay soil with phosphate buffer in order to establish an extraction method that would be effective, accurate and with minimal or no species interconversions. The Cr(VI) concentration in soil extracts was determined by speciated isotope dilution inductively coupled plasma mass spectrometry (SID-ICP-MS). The study was performed on soil samples from a field treated with tannery waste for 17 years. Samples were spiked by enriched stable isotopic solutions of (50)Cr(VI) and (53)Cr(III) that were added to phosphate buffers (0.1 M KH2PO4-K2HPO4 (pH 7.2) and/or 0.1 M K2HPO4 (pH 8)). To optimize extraction, mechanical shaking and/or ultrasound-assisted extraction were compared. The separation and detection of Cr species was performed by high-performance liquid chromatography (HPLC) ICP-MS. When mechanical shaking was applied, 90 % reduction of Cr(VI) was induced by extraction with 0.1 M KH2PO4-K2HPO4, while with 0.1 M K2HPO4 reduction was around 40 %. To shorten the extraction time and the possibility of species interconversions, ultrasound-assisted extraction was further applied only with 0.1 M K2HPO4. For total extraction of exchangeable Cr(VI) with a maximum 10 % reduction of Cr(VI), five consecutive ultrasound-assisted extractions were needed.

  2. Biochar effects on wet and dry regions of the soil water retention curve of a sandy loam

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Moldrup, Per; Sun, Zhencai

    2014-01-01

    Reported beneficial effects of biochar on soil physical properties and processes include decreased soil density, and increased soil water transport, water holding capacity and retention (mainly for the wet region). Research is limited on biochar effects on the full soil water retention curve (wet...... and dry regions) for a given soil and biochar amendment scenarios. This study evaluates how biochar applied to a sandy loam field at rates from 0 to 50 Mg ha−1 yr–1 in 2011, 2012, or both years (2011+2012) influences the full water retention curve. Inorganic fertilizer and pig slurry were added to all...... treatments. Six months after the last biochar application, intact and disturbed soil samples were collected for analyses. Soil water retention was measured from −1 kPa to −100 kPa using tension tables and ceramic plates and from −10 MPa to −480 MPa using a Vapor Sorption Analyzer. Soil specific area...

  3. Changes to soil water content and biomass yield under combined maize and maize-weed vegetation with different fertilization treatments in loam soil

    Directory of Open Access Journals (Sweden)

    Lehoczky Éva

    2016-06-01

    Full Text Available Especially during early developmental stages, competition with weeds can reduce crop growth and have a serious effect on productivity. Here, the effects of interactions between soil water content (SWC, nutrient availability, and competition from weeds on early stage crop growth were investigated, to better understand this problem. Field experiments were conducted in 2013 and 2014 using long-term study plots on loam soil in Hungary. Plots of maize (Zea mays L. and a weed-maize combination were exposed to five fertilization treatments. SWC was observed along the 0–80 cm depth soil profile and harvested aboveground biomass (HAB was measured.

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

    Science.gov (United States)

    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

  5. The Influence Of Loam Type And Cement Content On The Compressive Strength Of Rammed Earth

    Directory of Open Access Journals (Sweden)

    Narloch P. L.

    2015-03-01

    Full Text Available Currently, a worldwide dynamic rise of interest in using soil as a construction material can be observed. This trend is evident in the rapid rise of the amount of standards that deal with soil techniques. In 2012 the number of standards was larger by one third than five years prior. To create a full standardization of the rammed earth technique it is necessary to take into account the diversity of used soil and stabilizing additives. The proportion of the components, the process of element production and the research methods must also be made uniform. The article describes the results of research on the compressive strength of rammed earth samples that differed from each other with regards to the type of loam used for the mixture and the amount of the stabilizer. The stabilizer used was Portland cement CEM I 42.5R. The research and the analysis of the results were based on foreign publications, the New Zealand standard NZS 4298:1998, the American Standard NMAC14.7.4 and archival Polish Standards from the 1960’s that dealt with earth material.

  6. Influence of N,K and CaSO4 on utilisation of sulfur by rice in red sandy loam soil

    International Nuclear Information System (INIS)

    Patnaik, M.C.; Sathe, Arun

    1993-01-01

    A greenhouse study with rice on red sandy loam soil showed that uptake of sulphur increased from both native as well as applied source with increase in the application of sulphur from 20-60 kg S ha -1 through gypsum. The grain yields were influenced by nitrogen application but there was only relative increase with the application of potassium and sulphur. There was positive effect of applied nitrogen and sulphur for the total sulphur removal by the rice crop. The per cent sulphur utilisation decreased with increase in sulphur application from 20-60 kg S ha -1 through gypsum but increased with increase in the application of nitrogen from 0-150 kg N ha -1 . Sulphur utilization by rice crop was more in potassium treated pots compared to that without its application. (author). 7 refs., 3 tabs

  7. Evaluation of the the temperature and humidity effect in the Atrazine degradation in the Saldana soil (Tolima) for liquid chromatography of high resolution

    International Nuclear Information System (INIS)

    Acevedo Buitrago Baudilio; Guerrero Jairo A; Lozano Amanda; Fuentes Cilia

    2000-01-01

    In this study was designed an experiment under laboratory conditions with temperature and soil moisture controlled. The effect of these two factors was evaluated in atrazine degradation in silty loam soil, pH 6.23 (1:1 w), and 1.48% organic carbon. The extraction process of AT and deetilatrazine (DEA), and deisopropilatrazine (DIA) metabolites of the soil was carried out with methanol followed by a clean up with dichloromethane-buffer phosphate pH 10,0.01 M. Separation and quantification of the compounds was carried out by high performance liquid chromatography (HPLC). Soil moisture was not a significant factor in atrazine degradation process, while the temperature was the factor that regulates the herbicide degradation. Atrazine degradation at 30oC was faster than at 20o C. DIA and DEA metabolites were not detected in any soil field samples

  8. Soil water retention, air flow and pore structure characteristics after corn cob biochar application to a tropical sandy loam

    DEFF Research Database (Denmark)

    Amoakwah, Emmanuel; Frimpong, Kwame Agyei; Okae-Anti, D

    2017-01-01

    Soil structure is a key soil physical property that affects soil water balance, gas transport, plant growth and development, and ultimately plant yield. Biochar has received global recognition as a soil amendment with the potential to ameliorate the structure of degraded soils. We investigated how...... corn cob biochar contributed to changes in soil water retention, air flow by convection and diffusion, and derived soil structure indices in a tropical sandy loam. Intact soil cores were taken from a field experiment that had plots without biochar (CT), and plots each with 10 t ha− 1 (BC-10), 20 t ha...... to significant increase in soil water retention compared to the CT and BC-10 as a result of increased microporosity (pores biochar had minimal impact. No significant influence of biochar was observed for ka and Dp/D0 for the BC treatments compared to the CT despite...

  9. Laboratory and field evaluation of broiler litter nitrogen mineralization.

    Science.gov (United States)

    Sistani, K R; Adeli, A; McGowen, S L; Tewolde, H; Brink, G E

    2008-05-01

    Two studies were conducted for this research. First, a laboratory incubation to quantify broiler litter N mineralization with the following treatments: two soil moisture regimes, constant at 60% water fill pore space (WFPS) and fluctuating (60-30% WFPS), three soil types, Brooksville silty clay loam, Ruston sandy loam from Mississippi, and Catlin silt loam from Illinois. Second, a field incubation study to quantify broiler litter N mineralization using similar soils and litter application rates as the laboratory incubation. Broiler litter was applied at an equivalent rate of 350 kg total N ha(-1) for both studies except for control treatments. Subsamples were taken at different timing for both experiments for NO3-N and NH4-N determinations. In the laboratory experiment, soil moisture regimes had no significant impact on litter-derived inorganic N. Total litter-derived inorganic N across all treatments increased from 23 mg kg(-1) at time 0, to 159 mg kg(-1) at 93 d after litter application. Significant differences were observed among the soil types. Net litter-derived inorganic N was greater for Brooksville followed by Ruston and Catlin soils. For both studies and all soils, NH4-N content decreased while NO3-N content increased indicating a rapid nitrification of the mineralized litter N. Litter mineralization in the field study followed the same trend as the laboratory study but resulted in much lower net inorganic N, presumably due to environmental conditions such as precipitation and temperature, which may have resulted in more denitrification and immobilization of mineralized litter N. Litter-derived inorganic N from the field study was greater for Ruston than Brooksville. Due to no impact by soil moisture regimes, additional studies are warranted in order to develop predictive relationships to quantify broiler litter N availability.

  10. Plant uptake and soil retention of phthalic acid applied to Norfolk sandy loam

    International Nuclear Information System (INIS)

    Dorney, J.R.; Weber, J.B.; Overcash, M.R.; Strek, H.J.

    1985-01-01

    Plant uptake and soil retention of 14 C carboxyl-labeled phthalic acid were studied at application rates of 0.6, 6.0, 60.0, and 600.0 ppm (soil dry weight) to Norfolk sandy loam (Typic Paleudult, fine loamy, kaolinitic, thermic). Height and dry weight of corn (Zea mays L. Pioneer 3368A) (21 day), tall fescue (Festuca arundinacea Schreb. Kentucky 31) (45 day) immature soybean (Glycine max (L.) Merr. Altoona) (21 day) plant, mature soybean plant, and mature wheat (Triticum aestivum L. Butte) straw were not affected by phthalic acid applied to soil. In addition, soybean seed and wheat seed dry weight were unaffected. Immature wheat (40 day) height decreased at the 600 ppm rate. Plant uptake of phthalic acid ranged from 0 to 23 ppm and was significantly above background for all plants and plant materials except soybean pods. Fescue and immature plants exhibited the highest concentration of phthalic acid while mature wheat plants and wheat seeds exhibited the least. Most of the phthalic acid volatilized or was decomposed from the soil by the end of the study; an average of only 5.7% of the originally applied chemical was recovered in both soil or plants. An average of 0.02% of the originally applied phthalic acid leached out of the treated zone. Considering the low toxicity of phthalic acid and its relatively rapid disappearance from soil, it is unlikely to become a health hazard from contaminated plants. However, plant uptake of other toxic organics could potentially become a hazard on soils treated with sludge containing significant quantities of these substances

  11. Field Performance of Nine Soil Water Content Sensors on a Sandy Loam Soil in New Brunswick, Maritime Region, Canada

    Directory of Open Access Journals (Sweden)

    Lionel Stevens

    2009-11-01

    Full Text Available An in situ field test on nine commonly-used soil water sensors was carried out in a sandy loam soil located in the Potato Research Center, Fredericton, NB (Canada using the gravimetric method as a reference. The results showed that among the tested sensors, regardless of installation depths and soil water regimes, CS615, Trase, and Troxler performed the best with the factory calibrations, with a relative root mean square error (RRMSE of 15.78, 16.93, and 17.65%, and a r2 of 0.75, 0.77, and 0.65, respectively. TRIME, Moisture Point (MP917, and Gopher performed slightly worse with the factory calibrations, with a RRMSE of 45.76, 26.57, and 20.41%, and a r2 of 0.65, 0.72, and 0.78, respectively, while the Gypsum, WaterMark, and Netafim showed a frequent need for calibration in the application in this region.

  12. Water use efficiency in potatoes crop using nuclear techniques in Tumbaco - Ecuador

    International Nuclear Information System (INIS)

    Calvache, Marcelo; Ontaneda, Milton; Flor Jorge.

    1986-01-01

    The optimum water layer for potatoes (Solanum tuberosum L.) was computed by the balance of mass method. This project was carried out in a Typic Ustropepts, Silty-Loam Soil at 'La Tola' Experimental Field. Soil humidity was determined through the neutron probe. Irrigation efficiency for the first application layer, - layer 3- (30 days old crop), was 17%. It was increased to 34% at the age of 100 days. Layer 2 was increased to 25% and layer 1 to 20%. By this time the crop was developed. Crop water consumptive usage at layer 3 was 476.4 mm; 355.7 mm in layer 2; 390.5 mm for layer 1 and 269.3 mm in layer 0. Yield production was of the 29. 24.; 18.4 and 15. Kg/ha respectively. It is concluded that the timely application of water to potato crops is very important

  13. Assessing PAH removal from clayey soil by means of electro-osmosis and electrodialysis

    DEFF Research Database (Denmark)

    Lima, Ana T.; Ottosen, Lisbeth M.; Heister, Katja

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAH) are persistent and toxic contaminants which are difficult to remove from fine porous material like clayey soils. The present work aims at studying two electroremediation techniques for the removal of PAHs from a spiked natural silt soil from Saudi Arabia...... and a silty loam soil from The Netherlands which has been exposed to tar contamination for over 100years. The two techniques at focus are electro-osmosis and electrodialysis. The latter is applied for the first time for the removal of PAH. The efficiency of the techniques is studied using these two soils......, having been subjected to different PAH contact times.Two surfactants were used: the non-ionic surfactant Tween 80 and anionic surfactant sodium dodecyl sulphate (SDS) to aid desorption of PAHs from the soil. Results show a large discrepancy in the removal rates between spiked soil and long-term field...

  14. Models for prediction of soil precompression stress from readily available soil properties

    DEFF Research Database (Denmark)

    Schjønning, Per; Lamandé, Mathieu

    2018-01-01

    matric potentials. σpc was estimated from the original stress-strain curves by a novel, numerical method for estimating the stress at maximum curvature, assumingly partitioning the curve into elastic and plastic sections. Multiple regression was used to identify the drivers best describing the variation......Compaction of the subsoil is an almost irreversible damage to the soil resource. Modern machinery exerts high mechanical stresses to the subsoil, and a range of studies report significant effects on soil functions. There is an urgent need for quantitative knowledge of soil strength in order...... to evaluate sustainability of current field traffic. The aim of this study was to identify the most important drivers of soil precompression stress, σpc, and to develop pedotransfer functions for prediction of σpc. We revisited previously published data on σpc for a silty clay loam soil at a range of soil...

  15. Description of the physical environment and coal-mining history of west-central Indiana, with emphasis on six small watersheds

    International Nuclear Information System (INIS)

    Martin, J.D.; Crawford, C.G.; Duwelius, R.F.; Renn, D.E.

    1990-01-01

    West-central Indiana is underlain by coal-bearing Pennsylvanian rocks. Nearly all of the area has been glaciated at least once and is characterized by wide flood plains and broad, flat uplands. The most productive aquifers are confined or unconfined outwash aquifers located along the major rivers. Bedrock aquifers are regionally insignificant but are the sole source of groundwater for areas that lack outwash, alluvium, or sand and gravel lenses in till. Indiana has > 17 billion short tons of recoverable coal reserves; about 11% can be mined by surface methods. More than 50,000 acres in west-central Indiana were disturbed by surface coal mining from 1941 through 1980. Ridges of mine spoil have been graded to a gently rolling topography. Soils are well drained and consist of 6 to 12 inches of silt-loam topsoil that was stockpiled and then replaced over shale and sandstone fragments of the graded mine spoil. Grasses and legumes form the vegetative cover in each watershed. Pond Creek and the unnamed tributary to Big Branch are streams that drain mined and unreclaimed watersheds. Approximately one-half of the Pond Creek watershed is unmined,agricultural land. Soils are very well drained shaly silty loams that have formed on steeply sloping spoil banks. Both watersheds contain numerous impoundments of water and have enclosed areas that do not contribute surface runoff to streamflow. The ridges of mine spoil are covered with pine trees, but much of the soil surface is devoid of vegetation

  16. Root distribution of paddy and wheat grown on differing soil and water conditions

    International Nuclear Information System (INIS)

    Jha, M.N.; Subbiah, B.V.

    1977-01-01

    Two varieties of paddy and one variety of wheat were grown on two soil texture types - paddy on silty clay loam and wheat on sandy loam. Wheat crop was grown on a well drained plot and given normally scheduled irrigation while paddy was given normal and restricted irrigation. The root distribution pattern of these crops was determined. Under normal irrigation, NP 130 showed greater proportion of roots in a soil zone of 16 cm depth and 16.5 cm lateral distance. In case of Padma, the trend was similar to NP 130. More roots were found in a soil zone of 8 cm depth and 22.5 cm lateral distance. Under restricted irrigation, NP 130 showed greater proportion upto 16 cm depth and 22.5 cm lateral distance. In case of Padma, larger proportion of roots was found to be in a soil zone of 8 cm depth and 16.5 cm lateral distance. The root distribution of wheat described almost cylindrical geometry with little overall lateral growth. Regardless of treatments, roots showed a tendency to describe a cylindrical geometry (of about 1.5 cm dia and 32 cm depth). Water stress does effect the root distribution pattern of crops. Other conditions remaining the same, the narrow root cylinder described by the crops of paddy and wheat could possibly be a genetically controlled behaviour. 32 P plant injection technique was used in the study. (author)

  17. Transport of atrazine and dicamba through silt and loam soils

    Science.gov (United States)

    Tindall, James A.; Friedel, Michael J.

    2016-01-01

    The objectives of this research were to determine the role of preferential flow paths in the transport of atrazine (2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine) and dicamba (3-6-dichloro-2-methoxybenzoic acid) through silt and loam soils overlying the High Plains aquifer in Nebraska. In a previous study, 3 of 6 study areas demonstrated high percentages of macropores; those three areas were used in this study for analysis of chemical transport. As a subsequent part of the study, 12 intact soil cores (30-cm diameter by 40-cm height), were excavated sequentially, two from each of the following depths: 0-40cm and 40-80cm. These cores were used to study preferential flow characteristics using dye staining and to determine hydraulic properties. Two undisturbed experimental field plots, each with a 3-m2 surface area, were installed in three study areas in Nebraska. Each was instrumented with suction lysimeters and tensiometers at depths of 10cm to 80cm in 10-cm increments. Additionally, each plot was planted with corn (Zea mays). A neutron probe access tube was installed in each plot to determine soil w ater content at 15-cm intervals. All plots were enclosed w ith a raised frame (of 8-cm height) to prevent surface runoff. All suction lysimeters were purged monthly for three months and were sampled immediately prior to pre-plant herbicide application to obtain background chemical concentrations. Atrazine and dicamba moved rapidly through the soil, but only after a heavy rainfall event, probably owing to the presence of preferential flow paths and lack of microbial degradation in these soil areas. Staining of laboratory cores showed a positive correlation between the percent area stained by depth and the subsequent breakthrough of Br- in the laboratory and leaching of field-applied herbicides owing to large rainfall events. Suction lysimeter samples in the field showed increases in concentrations of herbicides at depths where laboratory data indicated greater

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

    Science.gov (United States)

    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

  19. Depth distribution of preferential flow patterns in a sandy loam soil as affected by tillage

    Directory of Open Access Journals (Sweden)

    C. T. Petersen

    1997-01-01

    Full Text Available Dye-tracer studies using the anionic dye Brilliant Blue FCF were conducted on a structured sandy loam soil (Typic Agrudalf. 25 mm of dye solution was applied to the surface of 11 1.6 x 1.6 m field plots, some of which had been subjected to conventional seed bed preparation (harrowing while others had been rotovated to either 5 or 15 cm depth before sowing. The soil was excavated to about 160 cm depth one or two days after dye application. Flow patterns and structural features appearing on vertical or horizontal cross sections were examined and photographed. The flow patterns were digitized, and depth functions for the number of activated flow pathways and the degree of dye coverage were calculated. Dye was found below 100 cm depth on 26 out of 33 vertical cross sections made in conventionally tilled plots showing that preferential flow was a prevailing phenomenon. The depth-averaged number of stained flow pathways in the 25-100 cm layer was significantly smaller in a plot rotovated to 5 cm depth than in a conventionally tilled plot, both under relatively dry initial soil conditions and when the entire soil profiles were initially at field capacity. There were no examples of dye penetration below 25 cm depth one month after deep rotovation. Distinct horizontal structures in flow patterns appearing at 20-40 cm depth coupled with changes in flow domains indicated soil layering with abrupt changes in soil structure and hydraulic properties.

  20. Empirical Models for Power and Energy Requirements II : A Powered Implement Operation in Serdang Sandy Clay Loam, Malaysia

    Directory of Open Access Journals (Sweden)

    A. F. Kheiralla

    2017-12-01

    Full Text Available Power and energy requirements were measured with an instrumented tractor for rotary tilling in Serdang sandy clay loam soil.  The effects of travel speed and rotor speed upon the measured data were investigated.  Power model from orthogonal regression analysis was formulated based on linear and quadratic functions of travel speed and bite length.  Fuel consumption model from regression analysis was formulated based on linear tractor PTO power as well as linear equivalent tractor PTO power.  Fuel consumption rates predicted by ASAE D497.3 were found to be 25% to 28% overestimates of the values predicted by the model developed.  However, fuel consumption rates reported by OECD Tractor Test were found to be 1% to 9% lower than the fuel consumption rates predicted by the model developed.  A comparison of power and energy requirements for both powered and draught implements showed that the disk harrow was the most energy efficient implement in terms of fuel consumption and specific energy followed by the rotary tiller, disk plough and mouldboard.  Finally, average PTO power, fuel consumption, wheel slip, wheel power and specific energy for a powered implement are presented.

  1. Elevated gas hydrate saturation within silt and silty clay sediments in the Shenhu area, South China Sea

    Science.gov (United States)

    Wang, Xiujuan; Hutchinson, Deborah R.; Wu, Shiguo; Yang, Shengxiong; Guo, Yiqun

    2011-01-01

    Gas hydrate saturations were estimated using five different methods in silt and silty clay foraminiferous sediments from drill hole SH2 in the South China Sea. Gas hydrate saturations derived from observed pore water chloride values in core samples range from 10 to 45% of the pore space at 190–221 m below seafloor (mbsf). Gas hydrate saturations estimated from resistivity (Rt) using wireline logging results are similar and range from 10 to 40.5% in the pore space. Gas hydrate saturations were also estimated by P wave velocity obtained during wireline logging by using a simplified three-phase equation (STPE) and effective medium theory (EMT) models. Gas hydrate saturations obtained from the STPE velocity model (41.0% maximum) are slightly higher than those calculated with the EMT velocity model (38.5% maximum). Methane analysis from a 69 cm long depressurized core from the hydrate-bearing sediment zone indicates that gas hydrate saturation is about 27.08% of the pore space at 197.5 mbsf. Results from the five methods show similar values and nearly identical trends in gas hydrate saturations above the base of the gas hydrate stability zone at depths of 190 to 221 mbsf. Gas hydrate occurs within units of clayey slit and silt containing abundant calcareous nannofossils and foraminifer, which increase the porosities of the fine-grained sediments and provide space for enhanced gas hydrate formation. In addition, gas chimneys, faults, and fractures identified from three-dimensional (3-D) and high-resolution two-dimensional (2-D) seismic data provide pathways for fluids migrating into the gas hydrate stability zone which transport methane for the formation of gas hydrate. Sedimentation and local canyon migration may contribute to higher gas hydrate saturations near the base of the stability zone.

  2. Distinguishing between natural and aquaculture-derived sediment concentrations of heavy metals in the Broughton Archipelago, British Columbia

    International Nuclear Information System (INIS)

    Sutherland, T.F.; Petersen, S.A.; Levings, C.D.; Martin, A.J.

    2007-01-01

    Marine sediment samples were collected in the Broughton Archipelago, British Columbia, to assess the use of a geochemical normalization technique in the identification of a chemical tracer of aquaculture waste material. Zinc and copper were suggested as tracers of feed pellets, while copper was considered an indicator of anti-foulant agents used on netpen systems. The sediment samples were analyzed for carbon, nitrogen, organic matter, water, trace-element, and free sulfide concentrations, and sediment grain-size distribution. Sediment texture analysis revealed a wide range of substrate types from sand to silty loam categories. Strong relationships between sediment texture, sediment porosity, and organic content were observed across both near-field and far-field stations. Excess zinc and copper sediment concentrations, identified using a lithium-normalization technique, were restricted to near-field sampling stations (0 and 30 m from netpen systems). The relationships between these metal tracers and organic content and sulfur concentrations were explored to account for variations in sediment concentrations of zinc and copper

  3. Seal Formation Mechanism Beneath Animal Waste Holding Ponds

    Science.gov (United States)

    Cihan, A.; Tyner, J. S.; Wright, W. C.

    2005-12-01

    Infiltration of animal waste from holding ponds can cause contamination of groundwater. Typically, the initial flux from a pond decreases rapidly as a seal of animal waste particulates is deposited at the base of the pond. The purpose of this study was to investigate the mechanism of the seal formation. Twenty-four soil columns (10-cm diameter by 43-cm long) were hand-packed with sand, silty loam or clay soils. A 2.3 m column of dairy or swine waste was applied to the top of the each column. The leakage rate from each column was measured with respect to time to analyze the effect of seal formation on different soil textures and animal waste types. We tested our hypothesis that seal growth and the subsequent decrease of leachate production adheres to a filter cake growth model. Said model predicts that the cumulative leakage rate is proportional to the square root of time and to the square root of the height of the waste.

  4. Simulation of groundwater flows in unsaturated porous media

    International Nuclear Information System (INIS)

    Musy, A.

    1976-01-01

    Groundwater flow in unsaturated porous media is caused by a potential gradient where the total potential consists of the sum of a gravitational and a suction component. The partial differential equations which result from the general analysis of groundwater flow in unsaturated soil are solved by succesive approximations with the finite-element method. General boundary and initial conditions, linear or curvilinear shaped elements (isoparametric elements) and steady-state or transient flow can be introduced into the numerical computer program. The results of this mathematical model are compared with experimental data established in the laboratory with a physical groundwater model. This is a rectangular testing tank of dimension 3 x 1.5 x 0.15 m and contains a silty clay loam. The variation of the bulk density and the volumetric moisture of the soil as a function of time and space are measured by gamma absorption from a 137 Cs source with 300 mCi intensity

  5. Agrogenic degradation of soils in Krasnoyarsk forest-steppe

    Science.gov (United States)

    Shpedt, A. A.; Trubnikov, Yu. N.; Zharinova, N. Yu.

    2017-10-01

    Agrogenic degradation of soils in Krasnoyarsk forest-steppe was investigated. Paleocryogenic microtopography of microlows and microhighs in this area predetermined the formation of paragenetic soil series and variegated soil cover. Specific paleogeographic conditions, thin humus horizons and soil profiles, and long-term agricultural use of the land resulted in the formation of soils unstable to degradation processes and subjected to active wind and water erosion. Intensive mechanical soil disturbances during tillage and long-term incorporation of the underlying Late Pleistocene (Sartan) calcareous silty and clay loams into the upper soil horizons during tillage adversely affected the soil properties. We determined the contents of total and labile humus and easily decomposable organic matter and evaluated the degree of soil exhaustion. It was concluded that in the case of ignorance of the norms of land use and soil conservation practices, intense soil degradation would continue leading to complete destruction of the soil cover within large areas.

  6. Phosphorus application to cotton enhances growth, yield, and quality characteristics on a sandy loam soil

    International Nuclear Information System (INIS)

    Ahmad, M.; Ranjha, A.M.

    2009-01-01

    Phosphorus (P) is the second most limiting nutrient in cotton (Gossypium hirsutum L.) production after nitrogen. Under wheat-cotton cropping system of Pakistan most of the farmers apply P fertilizer only to wheat crop. A field experiment was conducted to evaluate the effect of fertilizer P on the growth, yield and fibre quality of cotton on a sandy loam calcareous soil at farmer's field in cotton growing area of district Khanewal, Punjab. Five levels of P (0, 17, 26, 34 and 43 kg P ha /sup -1/) along with 120 kg N and 53 kg K ha/sup -1/ were applied. The response of cotton growth parameters was greater than quality components to P addition in calcareous soil. There was significant increase in the growth and yield parameters with each additional rate of P. The response of number of bolls per plant, boll weight and seed cotton yield was to the tune of 88.23, 16.82 and 42%, respectively at P application rate of 34 kg ha/sup -1/. Cotton quality components (lint %age, fiber length and fiber strength) improved from 2 to 5% where 43 kg P ha/sup -1/ was added. The lint and seed P concentration was little affected by P application as compared to stem and leaves showing its essentiality for cell division and development of meristematic tissue. Phosphorus use, thus not only valuable for wheat crop but also its application to cotton crop is of vital importance in improving both lint yield and quality. (author)

  7. Design and Testing of an Agricultural Implement for Underground Application of Rodenticide Bait

    Directory of Open Access Journals (Sweden)

    Hugo Malón

    2015-01-01

    Full Text Available An agricultural implement for underground application of rodenticide bait to control the Mediterranean pocket gopher (Microtus Duodecimcostatus in fruit orchards has been designed and tested. The main objective of this research was to design and test the implement by using the finite element method (FEM and considering a range of loads generated on most commonly used furrow openers in agricultural implements. As a second step, the prototype was tested in the field by analysing the effects of forward speed and application depth on the mechanical behaviour of the implement structure. The FEM was used in the design phase and a prototype was manufactured. The structural strains on the prototype chassis under working conditions were tested by using strain gauges to validate the design phase. Three forward speeds (4.5, 5.5, and 7.0 km/h, three application depths (0.12, 0.15, and 0.17 m, and two types of soil (clayey-silty-loam and clayey-silty-sandy were considered. The prototype was validated successfully by analysing the information obtained from the strain gauges. The Von Mises stresses indicated a safety coefficient of 1.9 for the most critical load case. Although both forward speed and application depth had a significant effect on the stresses generated on the chassis, the latter parameter critically affected the structural behaviour of the implement. The effects of the application depth on the strains were linear such that strains increased with depth. In contrast, strains remained roughly constant regardless of variation in the forward speed.

  8. Analysis of some parameters related to the hydraulic infiltration of a silty-loam soil subjected to organic and mineral fertilizer systems in Southern Italy

    Directory of Open Access Journals (Sweden)

    Antonietta Napolitano

    2011-05-01

    Full Text Available This experiment was carried out to detect the most linear process to calculate the hydraulic conductivity, with the aim to classify the soil of experimental station of the Unit for Research in Cultivations Alternative to Tobacco (CAT, locate in South Italy (Scafati, Province of Salerno, subject to different types of manure: compost and mineral fertilizer. The field tests were made by a system measuring infiltration by double, inner and outer ring, inserted into the ground. Each ring was supplied with a constant level of water from external bottle (3 cm, and hydraulic conductivity is determined when the water flow rate in the inner ring is constant. Four areas, two fertilized by mineral fertilizer (areas I and III and two amended with compost (areas II and IV at two depths, 5 and 10 cm (H1-H2, were analysed. The parameters were recorded at the following dates: on 18th and 19th September 2009, respectively, at 5 and 10 cm of depth (H1-H2 in area I; on 7th and 8th October 2009 in area II; on 13th and 14th October 2009 in area III; on 16th and 17th October 2009 in area IV. The effect of compost, used one time only, is present in all parameters, even if with a low statistical significance (P<0.01-0.05. This biomass stores a better water reserve [g (100 g–1-Δθ] and causes a lower avidity for water (bibacity and a better speed of percolation (Ks of exceeding water. The organic matter decreased the variability of soil along field. The studied soil showed to be almost permeable and not having any serious problem concerning rain intensity.

  9. Uncertainty of Deardorff’s soil moisture model based on continuous TDR measurements for sandy loam soil

    Directory of Open Access Journals (Sweden)

    Brandyk Andrzej

    2016-03-01

    Full Text Available Knowledge on soil moisture is indispensable for a range of hydrological models, since it exerts a considerable influence on runoff conditions. Proper tools are nowadays applied in order to gain in-sight into soil moisture status, especially of uppermost soil layers, which are prone to weather changes and land use practices. In order to establish relationships between meteorological conditions and topsoil moisture, a simple model would be required, characterized by low computational effort, simple structure and low number of identified and calibrated parameters. We demonstrated, that existing model for shallow soils, considering mass exchange between two layers (the upper and the lower, as well as with the atmosphere and subsoil, worked well for sandy loam with deep ground water table in Warsaw conurbation. GLUE (Generalized Likelihood Uncertainty Estimation linked with GSA (Global Sensitivity Analysis provided for final determination of parameter values and model confidence ranges. Including the uncertainty in a model structure, caused that the median soil moisture solution of the GLUE was shifted from the one optimal in deterministic sense. From the point of view of practical model application, the main shortcoming were the underestimated water exchange rates between the lower soil layer (ranging from the depth of 0.1 to 0.2 m below ground level and subsoil. General model quality was found to be satisfactory and promising for its utilization for establishing measures to regain retention in urbanized conditions.

  10. Overland Transport of Rotavirus and the Effect of Soil Type and Vegetation

    Directory of Open Access Journals (Sweden)

    Paul C. Davidson

    2016-03-01

    Full Text Available Soil and vegetation are two critical factors for controlling the overland transport kinetics of pathogens in a natural environment. With livestock operations moving more towards concentrated animal operations, the need to dispose of a very large amount of manure in a localized area is becoming increasingly important. Animal manure contains a substantial amount of microbial pathogens, including rotavirus, which may pose a threat of contamination of water resources. This study examined the kinetics of rotavirus in overland transport, with an overall objective of optimizing the design of best management practices, especially vegetative filter strips. The overland transport of rotavirus was studied using three soil types (Catlin silt-loam, Darwin silty-clay, Alvin fine sandy-loam, spanning the entire spectrum of typical Illinois soil textures. A 20-min rainfall event was produced using a small-scale (1.07 m × 0.66 m laboratory rainfall simulator over a soil box measuring 0.610 m × 0.305 m. Each soil type was tested for rotavirus transport kinetics with bare surface conditions, as well as with Smooth Brome and Fescue vegetative covers. Surface runoff, near-surface runoff, soil cores, and vegetation were each analyzed for infective rotavirus particles using cell-culture infectivity assays. Results show that vegetation reduces the recovery of infective rotavirus particles in surface runoff by an average of 73%, in addition to delaying the time to peak recovery. The vegetation, in general, appeared to decrease the recovery of infective rotavirus particles in surface runoff by impeding surface flow and increasing the potential for infiltration into the soil profile.

  11. Simulation of chloride transport based description soil structure

    International Nuclear Information System (INIS)

    Mahmood-ul-Hassan, M.; Akhtar, M.S.; Gill, S.M.; Nabi, G.

    2003-01-01

    There is a need of environmental implications of rapid appearance of surface by applying chemical at depths below the vadose zone (tile line or shallow groundwater) for developing better insight into solute flow mechanism through the arable lands. Transport of chloride, a representative non-adsorbing solute, through a moderately structured silty clay loam soil (Gujranwala series, Typic Ustochrepts) and an un-structured sandy loam soil (Nabipur series, Typic Camborthid) was characterized and two existing models viz. convection dispersion equation (CDE) and preferential flow models were tested. The flux average of solute concentration in the outflow as a function of cumulative drainage was fitted to the models. The CDE fitted, relatively, better in the non-structured soil than in the moderately structured soil. Dispersivity value determined by CDE was very high for the structured soil which is physically not possible. The preferential flow model fitted well in the Gujranwala soil, but not in the Nabipur soil. The breakthrough characteristics i.e. drainage to peak concentration (Dp), symmetry coefficient (SC), skewness, and kurtosis were compared. Chloride breakthrough was earlier than expected based on piston flow. It indicated preferential flow in both the soils, yet, immediate appearance of the tracer in the Gujranwala soil demonstrated even larger magnitude of the preferential flow. Breakthrough curves' parameters indicated a large amount of the solute movement through the preferred pathways by passing the soil matrix in the Gujranwala soil. The study suggests that some soil structure parameters (size/shape and degree of aggregation) should be incorporated in the solute transport models.(author)

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

    Science.gov (United States)

    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.

  13. 78 FR 75335 - Intent To Grant an Exclusive License for a U.S. Government-Owned Invention

    Science.gov (United States)

    2013-12-11

    ..., ``Automated Inhalation Toxicology Exposure System and Method,'' and related foreign rights. The intended licensee is Biaera Technologies, LLC, with its principal place of business at 277 Eastern Boulevard North, Suite 3, Hagerstown, MD 21740. ADDRESSES: Commander, U.S. Army Medical Research and Materiel Command...

  14. Resistance of soil-bound prions to rumen digestion.

    Directory of Open Access Journals (Sweden)

    Samuel E Saunders

    Full Text Available Before prion uptake and infection can occur in the lower gastrointestinal system, ingested prions are subjected to anaerobic digestion in the rumen of cervids and bovids. The susceptibility of soil-bound prions to rumen digestion has not been evaluated previously. In this study, prions from infectious brain homogenates as well as prions bound to a range of soils and soil minerals were subjected to in vitro rumen digestion, and changes in PrP levels were measured via western blot. Binding to clay appeared to protect noninfectious hamster PrP(c from complete digestion, while both unbound and soil-bound infectious PrP(Sc proved highly resistant to rumen digestion. In addition, no change in intracerebral incubation period was observed following active rumen digestion of unbound hamster HY TME prions and HY TME prions bound to a silty clay loam soil. These results demonstrate that both unbound and soil-bound prions readily survive rumen digestion without a reduction in infectivity, further supporting the potential for soil-mediated transmission of chronic wasting disease (CWD and scrapie in the environment.

  15. SPATIAL MODELLING FOR DESCRIBING SPATIAL VARIABILITY OF SOIL PHYSICAL PROPERTIES IN EASTERN CROATIA

    Directory of Open Access Journals (Sweden)

    Igor Bogunović

    2016-06-01

    Full Text Available The objectives of this study were to characterize the field-scale spatial variability and test several interpolation methods to identify the best spatial predictor of penetration resistance (PR, bulk density (BD and gravimetric water content (GWC in the silty loam soil in Eastern Croatia. The measurements were made on a 25 x 25-m grid which created 40 individual grid cells. Soil properties were measured at the center of the grid cell deep 0-10 cm and 10-20 cm. Results demonstrated that PR and GWC displayed strong spatial dependence at 0-10 cm BD, while there was moderate and weak spatial dependence of PR, BD and GWC at depth of 10-20 cm. Semi-variogram analysis suggests that future sampling intervals for investigated parameters can be increased to 35 m in order to reduce research costs. Additionally, interpolation models recorded similar root mean square values with high predictive accuracy. Results suggest that investigated properties do not have uniform interpolation method implying the need for spatial modelling in the evaluation of these soil properties in Eastern Croatia.

  16. ALLELOPATHIC EFFECTS OF SOME PLANT SPECIES ON GROWTH AND DEVELOPMENT OF CROPS AND WEEDS

    Directory of Open Access Journals (Sweden)

    Igor Bogunović

    2016-06-01

    Full Text Available The objectives of this study were to characterize the field-scale spatial variability and test several interpolation methods to identify the best spatial predictor of penetration resistance (PR, bulk density (BD and gravimetric water content (GWC in the silty loam soil in Eastern Croatia. The measurements were made on a 25 x 25-m grid which created 40 individual grid cells. Soil properties were measured at the center of the grid cell deep 0-10 cm and 10-20 cm. Results demonstrated that PR and GWC displayed strong spatial dependence at 0-10 cm BD, while there was moderate and weak spatial dependence of PR, BD and GWC at depth of 10-20 cm. Semi-variogram analysis suggests that future sampling intervals for investigated parameters can be increased to 35 m in order to reduce research costs. Additionally, interpolation models recorded similar root mean square values with high predictive accuracy. Results suggest that investigated properties do not have uniform interpolation method implying the need for spatial modelling in the evaluation of these soil properties in Eastern Croatia.

  17. Resistance of Soil-Bound Prions to Rumen Digestion

    Science.gov (United States)

    Saunders, Samuel E.; Bartelt-Hunt, Shannon L.; Bartz, Jason C.

    2012-01-01

    Before prion uptake and infection can occur in the lower gastrointestinal system, ingested prions are subjected to anaerobic digestion in the rumen of cervids and bovids. The susceptibility of soil-bound prions to rumen digestion has not been evaluated previously. In this study, prions from infectious brain homogenates as well as prions bound to a range of soils and soil minerals were subjected to in vitro rumen digestion, and changes in PrP levels were measured via western blot. Binding to clay appeared to protect noninfectious hamster PrPc from complete digestion, while both unbound and soil-bound infectious PrPSc proved highly resistant to rumen digestion. In addition, no change in intracerebral incubation period was observed following active rumen digestion of unbound hamster HY TME prions and HY TME prions bound to a silty clay loam soil. These results demonstrate that both unbound and soil-bound prions readily survive rumen digestion without a reduction in infectivity, further supporting the potential for soil-mediated transmission of chronic wasting disease (CWD) and scrapie in the environment. PMID:22937149

  18. Biochar affects carbon composition and stability in soil: a combined spectroscopy-microscopy study

    Science.gov (United States)

    Hernandez-Soriano, Maria C.; Kerré, Bart; Kopittke, Peter M.; Horemans, Benjamin; Smolders, Erik

    2016-01-01

    The use of biochar can contribute to carbon (C) storage in soil. Upon addition of biochar, there is a spatial reorganization of C within soil particles, but the mechanisms remain unclear. Here, we used Fourier transformed infrared-microscopy and confocal laser scanning microscopy to examine this reorganization. A silty-loam soil was amended with three different organic residues and with the biochar produced from these residues and incubated for 237 d. Soil respiration was lower in biochar-amended soils than in residue-amended soils. Fluorescence analysis of the dissolved organic matter revealed that biochar application increased a humic-like fluorescent component, likely associated with biochar-C in solution. The combined spectroscopy-microscopy approach revealed the accumulation of aromatic-C in discrete spots in the solid-phase of microaggregates and its co-localization with clay minerals for soil amended with raw residue or biochar.The co-localization of aromatic-C:polysaccharides-C was consistently reduced upon biochar application. We conclude that reduced C metabolism is an important mechanism for C stabilization in biochar-amended soils. PMID:27113269

  19. Biochar affects carbon composition and stability in soil: a combined spectroscopy-microscopy study

    Science.gov (United States)

    Hernandez-Soriano, Maria C.; Kerré, Bart; Kopittke, Peter M.; Horemans, Benjamin; Smolders, Erik

    2016-04-01

    The use of biochar can contribute to carbon (C) storage in soil. Upon addition of biochar, there is a spatial reorganization of C within soil particles, but the mechanisms remain unclear. Here, we used Fourier transformed infrared-microscopy and confocal laser scanning microscopy to examine this reorganization. A silty-loam soil was amended with three different organic residues and with the biochar produced from these residues and incubated for 237 d. Soil respiration was lower in biochar-amended soils than in residue-amended soils. Fluorescence analysis of the dissolved organic matter revealed that biochar application increased a humic-like fluorescent component, likely associated with biochar-C in solution. The combined spectroscopy-microscopy approach revealed the accumulation of aromatic-C in discrete spots in the solid-phase of microaggregates and its co-localization with clay minerals for soil amended with raw residue or biochar.The co-localization of aromatic-C:polysaccharides-C was consistently reduced upon biochar application. We conclude that reduced C metabolism is an important mechanism for C stabilization in biochar-amended soils.

  20. The effect of EDTA and citric acid on phytoremediation of Cd, Cr, and Ni from soil using Helianthus annuus

    International Nuclear Information System (INIS)

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

    2004-01-01

    The possibility to clean heavy metal contaminated soils with hyperaccumulator plants has shown great potential. One of the most recently studied species used in phytoremediation applications are sunflowers. In this study, two cultivars of Helianthus annuus were used in conjunction with ethylene diamine tetracetic acid (EDTA) and citric acid (CA) as chelators. Two different concentrations of the chelators were studied for enhancing the uptake and translocation of Cd, Cr, and Ni from a silty-clay loam soil. When 1.0 g/kg CA was used, the highest total metal uptake was only 0.65 mg. Increasing the CA concentration posed a severe phytotoxicity to both cultivars as evidenced by stunted growth and diminished uptake rates. Decreasing the CA concentration to 0.1 and 0.3 g/kg yielded results that were not statistically different from the control. EDTA at a concentration of 0.1 g/kg yielded the best results for both cultivars achieving a total metal uptake of ∼0.73 mg compared to ∼0.40 mg when EDTA was present at 0.3 g/kg

  1. The effect of EDTA and citric acid on phytoremediation of Cd, Cr, and Ni from soil using Helianthus annuus.

    Science.gov (United States)

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

    2004-09-01

    The possibility to clean heavy metal contaminated soils with hyperaccumulator plants has shown great potential. One of the most recently studied species used in phytoremediation applications are sunflowers. In this study, two cultivars of Helianthus annuus were used in conjunction with ethylene diamine tetracetic acid (EDTA) and citric acid (CA) as chelators. Two different concentrations of the chelators were studied for enhancing the uptake and translocation of Cd, Cr, and Ni from a silty-clay loam soil. When 1.0 g/kg CA was used, the highest total metal uptake was only 0.65 mg. Increasing the CA concentration posed a severe phytotoxicity to both cultivars as evidenced by stunted growth and diminished uptake rates. Decreasing the CA concentration to 0.1 and 0.3 g/kg yielded results that were not statistically different from the control. EDTA at a concentration of 0.1 g/kg yielded the best results for both cultivars achieving a total metal uptake of approximately 0.73 mg compared to approximately 0.40 mg when EDTA was present at 0.3 g/kg.

  2. The effect of EDTA and citric acid on phytoremediation of Cd, Cr, and Ni from soil using Helianthus annuus

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-09-01

    The possibility to clean heavy metal contaminated soils with hyperaccumulator plants has shown great potential. One of the most recently studied species used in phytoremediation applications are sunflowers. In this study, two cultivars of Helianthus annuus were used in conjunction with ethylene diamine tetracetic acid (EDTA) and citric acid (CA) as chelators. Two different concentrations of the chelators were studied for enhancing the uptake and translocation of Cd, Cr, and Ni from a silty-clay loam soil. When 1.0 g/kg CA was used, the highest total metal uptake was only 0.65 mg. Increasing the CA concentration posed a severe phytotoxicity to both cultivars as evidenced by stunted growth and diminished uptake rates. Decreasing the CA concentration to 0.1 and 0.3 g/kg yielded results that were not statistically different from the control. EDTA at a concentration of 0.1 g/kg yielded the best results for both cultivars achieving a total metal uptake of {approx}0.73 mg compared to {approx}0.40 mg when EDTA was present at 0.3 g/kg.

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

    Science.gov (United States)

    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.

  4. "Snow Soup" Students Take on Animation Creation

    Science.gov (United States)

    Nikirk, Martin

    2009-01-01

    This article describes the process of producing "Snow Soup"--the 2009 Adobe Flash animation produced by the Computer Game Development and Animation seniors of Washington County Technical High School in Hagerstown, Maryland, for libraries in their area. In addition to the Flash product, the students produced two related Game Maker games, a printed…

  5. Bibliography of Ticks and Tickborne Diseases from Homer (About 800 B.C.) to 31 December 1981. Volume 7.

    Science.gov (United States)

    1982-05-01

    HUELI, L. E. (1979A) Estudlo del ciclo Medical Department, Harper & Row, biol6gico de Hya.joma rnarginatum Publishers; Hagerstown, Maryland...1980Ai Ciclo anual de Rep. Internat., 23(2):219-228. parasitismo por pulgas y garrapatas en el consejo de campo 12.S1oLI.us cuniculus L. ) en Andalucia

  6. Description of the physical environment and coal-mining history of west-central Indiana, with emphasis on six small watersheds

    Science.gov (United States)

    Martin, Jeffrey D.; Crawford, Charles G.; Duwelius, R.F.; Renn, D.E.

    1987-01-01

    Information on the geology, geomorphology, soils, climate, hydrology, water use, land use, population, and coal mining history of Clay, Owen, Sullivan, and Vigo Counties in Indiana is summarized. Site-specific information is given on the morphology , geology, soils, land use, coal mining history, and hydrologic instrumentation of the six watersheds which are each less than 3 sq mi in area. The Wabash, White, and Eel Rivers are the major drainages in west-central Indiana. Average annual precipitation is about 39.5 in/yr and average annual runoff is about 13 in/yr. The most productive aquifers are confined or unconfined outwash aquifers located along the major rivers. Bedrock aquifers are regionally insignificant but are the sole source of groundwater for areas that lack outwash, alluvium, or sand and gravel lenses in till. Indiana has more than 17 billion short tons of recoverable coal reserves; about 11% can be mined by surface methods. Almost half of Indiana 's surface reserves are in Clay, Owen, Sullivan, and Vigo Counties. More than 50,000 acres in west-central Indiana have been disturbed by surface coal mining from 1941 through 1980. Big Slough and Hooker Creek are streams that drain unmined, agricultural watersheds. Row-crop corn and soybeans are the principal crops. Soils are moderately well drained silt loams, and the watersheds well developed dendritic drainage systems. Unnamed tributaries drain mined and reclaimed watersheds. Ridges of mine spoil have been graded to a gently rolling topography. Soils are well drained and consist of 6 to 12 inches of silt-loam topsoil that was stockpiled and then replaced over shale and sandstone fragments of the graded mine spoil. Grasses and legumes form the vegetative cover in each watershed. Pond Creek and an unnamed tributary to Big Branch are streams that drain mined and unreclaimed watersheds. Soils are very well drained shaly silty loams that have formed on steeply sloping banks. Both watersheds contain numerous

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

    Directory of Open Access Journals (Sweden)

    Weiwei Lu

    Full Text Available 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.

  8. 78 FR 7458 - Petitions for Modification of Application of Existing Mandatory Safety Standards

    Science.gov (United States)

    2013-02-01

    .... Petitioner: Sterling Mining Corporation, P.O. Box 217, North Lima, Ohio 44452. Mines: Shean Hill, MSHA I.D... outlets and valves. 6. Due to the thin coal seam and low mining height, the pipes placed along the roof... Granules (Ione) LLC, 1101 Opal Court, Suite 315, Hagerstown, Maryland 21740. Mine: Ione Mine, MSHA I.D. No...

  9. Spring Research Festival Highlighted on WHAG-TV | Poster

    Science.gov (United States)

    WHAG-TV (Hagerstown, Md.) visited Fort Detrick to highlight the 2015 Spring Research Festival (SRF), sponsored by the National Interagency Confederation for Biological Research (NICBR). Visit the WHAG-TV website to see the video broadcast, which aired May 6. The video was produced by WHAG Reporter Mallory Sofastaii. The video featured Linganore High School senior Rebecca

  10. Degradation and leaching behaviour of 14C-glufosinate in a silty sand soil. Experiments in outdoor lysimeters with undisturbed soil cores

    International Nuclear Information System (INIS)

    Kubiak, R.

    1996-12-01

    Degradation and leaching behaviour of 14 C-labelled glufosinate in a silty sand soil was investigated in two outdoor lysimeters after repeated application of 12.5 litres/hectare (1/ha) Basta (divided in 7.5 and 5 l/ha respectively). The 14 C-loss during application was 4.8-8.2%. The 14 C-content in the plants (vines and weeds) was 0.3% of that applied at the most. After 130 days, 25.9 and 25.5% of the applied material was found in the soil up to a depth of 40 cm. One year after the first application, this amount was still 18.5 and 18.6%. As a consequence of the renewed spraying, the detected amounts of 14 C were 44.3 and 43.1% some 107 days after the first application in the second experimental year. The additional investigation in lysimeter 2 after 373 days showed a decrease to 33.9%. Most of the detected radioactivity remained in the 0-10 cm soil layer. At the end of the experiment, the amount of 14 C in the 30-40 cm layer was 0.5%. The total residues in the 0-10 cm soil layer were less than 1 mg/kg at all dates of sampling, and only a small amount still represented the free acid of the active ingredient. The average values were 0.05 mg/kg after 130 days, 0.01 mg/kg after 363 days and 0.09 mg/kg at the following date of sampling. In the spring of the following year, no residues of the free acid were detectable. The radioactivity in the percolate amounted to a maximum of 0.11% of that applied and in no case represented the free acid of the ammonium salt. (author)

  11. Combined impacts of land use and soil property changes on soil erosion in a mollisol area under long-term agricultural development.

    Science.gov (United States)

    Ouyang, Wei; Wu, Yuyang; Hao, Zengchao; Zhang, Qi; Bu, Qingwei; Gao, Xiang

    2018-02-01

    Soil erosion exhibits special characteristics in the process of agricultural development. Understanding the combined impacts of land use and soil property changes on soil erosion, especially in the area under long-term agricultural cultivations, is vital to watershed agricultural and soil management. This study investigated the temporal-spatial patterns of the soil erosion based on a modified version of Universal Soil Loss Equation (USLE) and conducted a soil erosion contribution analysis. The land use data were interpreted from Landsat series images, and soil properties were obtained from field sampling, laboratory tests and SPAW (Soil-Plant-Atmosphere-Water) model calculations. Over a long period of agricultural development, the average erosion modulus decreased from 187.7tkm -2 a -1 in 1979 to 158.4tkm -2 a -1 in 2014. The land use types were transformed mainly in the reclamation of paddy fields and the shrinking of wetlands on a large scale. Most of the soils were converted to loam from silty or clay loam and the saturated hydraulic conductivity (K s ) of most soil types decreased by 1.11% to 43.6%. The rapidly increasing area of 49.8km 2 of paddy fields together with the moderate decrease of 14.0km 2 of forests, as well as K s values explained 87.4% of the total variance in soil erosion. Although changes in soil physical and water characteristics indicated that soil erosion loads should have become higher, the upsurge in paddy fields played an important role in mitigating soil erosion in this study area. These results demonstrated that land use changes had more significant impacts than soil property changes on soil erosion. This study suggested that rational measures should be taken to extend paddy fields and control the dry land farming. These findings will benefit watershed agricultural targeting and management. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Parameter importance and uncertainty in predicting runoff pesticide reduction with filter strips.

    Science.gov (United States)

    Muñoz-Carpena, Rafael; Fox, Garey A; Sabbagh, George J

    2010-01-01

    Vegetative filter strips (VFS) are an environmental management tool used to reduce sediment and pesticide transport from surface runoff. Numerical models of VFS such as the Vegetative Filter Strip Modeling System (VFSMOD-W) are capable of predicting runoff, sediment, and pesticide reduction and can be useful tools to understand the effectiveness of VFS and environmental conditions under which they may be ineffective. However, as part of the modeling process, it is critical to identify input factor importance and quantify uncertainty in predicted runoff, sediment, and pesticide reductions. This research used state-of-the-art global sensitivity and uncertainty analysis tools, a screening method (Morris) and a variance-based method (extended Fourier Analysis Sensitivity Test), to evaluate VFSMOD-W under a range of field scenarios. The three VFS studies analyzed were conducted on silty clay loam and silt loam soils under uniform, sheet flow conditions and included atrazine, chlorpyrifos, cyanazine, metolachlor, pendimethalin, and terbuthylazine data. Saturated hydraulic conductivity was the most important input factor for predicting infiltration and runoff, explaining >75% of the total output variance for studies with smaller hydraulic loading rates ( approximately 100-150 mm equivalent depths) and approximately 50% for the higher loading rate ( approximately 280-mm equivalent depth). Important input factors for predicting sedimentation included hydraulic conductivity, average particle size, and the filter's Manning's roughness coefficient. Input factor importance for pesticide trapping was controlled by infiltration and, therefore, hydraulic conductivity. Global uncertainty analyses suggested a wide range of reductions for runoff (95% confidence intervals of 7-93%), sediment (84-100%), and pesticide (43-100%) . Pesticide trapping probability distributions fell between runoff and sediment reduction distributions as a function of the pesticides' sorption. Seemingly

  13. Exploratory Water Budget Analysis of A Transitional Premontane Cloud Forest in Costa Rica Through Undergraduate Research

    Science.gov (United States)

    Washington-Allen, R. A.; Buckwalter, E. H.; Moore, G. W.; Burns, J. N.; Dennis, A. R.; Dodge, O.; Guffin, E. C.; Morris, E. R.; Oien, R. P.; Orozco, G.; Peterson, A.; Teale, N. G.; Shibley, N. C.; Tourtellotte, N.; Houser, C.; Brooks, S. D.; Brumbelow, J. K.; Cahill, A. T.; Frauenfeld, O. W.; Gonzalez, E.; Hallmark, C. T.; McInnes, K. J.; Miller, G. R.; Morgan, C.; Quiring, S. M.; Rapp, A. D.; Roark, E.; Delgado, A.; Ackerson, J. P.; Arnott, R.

    2012-12-01

    The ecohydrology of transitional premontane cloud forests is not well understood. This problem is being addressed by a NSF Research Experience for Undergraduates (REU) study at the Texas A&M University Soltis Center for Research & Education in Costa Rica. Exploratory analysis of the water budget within a 20-ha watershed was used to connect three faculty-mentored research areas in ecohydrology, climate, and soil sciences and highlight the roles of 12 undergraduate researchers from 12 different universities. The water budget model is Q = Pn - E - T + ΔG + ΔS where Q = runoff, Pn = net precipitation, E = evaporation, T = transpiration, and ΔG and ΔS are change in groundwater soil water storage, respectively. Additionally, Pn = Pg - I = Tf + Sf + D, where Pg = gross precipitation, I/ΔI = canopy interception or storage, Tf = throughfall, Sf = stemflow, and D = canopy drip. The following terms were well understood Pg (satellite = 34-mm and tower = 38.1-mm) and Q from a recently constructed v-notch weir. We moderately understand Tf + D (30.9-mm from an array of forest rain gages), ΔI (7.2-mm) related to Sf, and T (10.4-mm measured with sapflow sensors). We found that soils were clay loam to silty loam textured Andisols on saprolitic tuft with a mean potential ΔS of 398 mm H2O under laboratory conditions, but in the field the following terms are almost completely unknown and require further field studies including E, ΔG, and ΔS. Recent installation of piezometers will address ΔG. Temporal scaling of measurements to a 1-week period was a challenge as well as the construction, deployment and calibration of instruments. However, this exploration allowed us to determine measurement uncertainties in the water budget, e.g., E, and to set future areas of research to address these uncertainties.

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

    Science.gov (United States)

    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.

  15. The use of modern data about the composition and properties of soils for the development of transport infrastructure of Tyumen

    Science.gov (United States)

    Eremin, Dmitry

    2017-10-01

    Sedimentary properties territory Tura-Pyshma interfluve, where Tyumen is located are determined by the general course of ancient and especially the newest tectonic movements. Active development of the transport network on the territory of the Tour-Pyshma interfluve has created the need for a contemporary study of regional peculiarities of grounds. This will allow you to create roads with the quality meet the international standards. The use of average values of indicators of the properties of silty-clay soils during the development of the transport infrastructure projects of the city of Tyumen and its environs is ineffective due to the genetic characteristics of the rocks located at the depth of 1.5-5.0 meters. Detailed analysis showed that the studied soil belongs to the covering carbonate loams and clays, differing in its characteristics from loess-like sediments of the European part of Russia. The thickness of the covering rocks is not more than 5 meters. It’s low-carbonate, non-saline and often has a layered structure. The upper three meters of sediments contain the minimum quantity of water-soluble salts (dry residue less than 0.1%). Studied covering loams are characterized by favorable physical properties: the density of the bulk and the particle is 1.44 to 1.62 and 2.70-2.78 g/cm3, respectively. Water permeability is high - the filtration coefficient varies from 3.4 to 6.4 m/day, the minimum water velocity observed in the clay types of soil. The presence of sand layers adversely affects the permeability of soil. Therefore, the design and construction of transport infrastructure of the city and the surrounding territories it is necessary to consider regional features of grounds.

  16. Degradation and leaching behaviour of {sup 14}C-glufosinate in a silty sand soil. Experiments in outdoor lysimeters with undisturbed soil cores

    Energy Technology Data Exchange (ETDEWEB)

    Kubiak, R

    1996-12-01

    Degradation and leaching behaviour of {sup 14}C-labelled glufosinate in a silty sand soil was investigated in two outdoor lysimeters after repeated application of 12.5 litres/hectare (1/ha) Basta (divided in 7.5 and 5 l/ha respectively). The {sup 14}C-loss during application was 4.8-8.2%. The {sup 14}C-content in the plants (vines and weeds) was 0.3% of that applied at the most. After 130 days, 25.9 and 25.5% of the applied material was found in the soil up to a depth of 40 cm. One year after the first application, this amount was still 18.5 and 18.6%. As a consequence of the renewed spraying, the detected amounts of {sup 14}C were 44.3 and 43.1% some 107 days after the first application in the second experimental year. The additional investigation in lysimeter 2 after 373 days showed a decrease to 33.9%. Most of the detected radioactivity remained in the 0-10 cm soil layer. At the end of the experiment, the amount of {sup 14}C in the 30-40 cm layer was 0.5%. The total residues in the 0-10 cm soil layer were less than 1 mg/kg at all dates of sampling, and only a small amount still represented the free acid of the active ingredient. The average values were 0.05 mg/kg after 130 days, 0.01 mg/kg after 363 days and 0.09 mg/kg at the following date of sampling. In the spring of the following year, no residues of the free acid were detectable. The radioactivity in the percolate amounted to a maximum of 0.11% of that applied and in no case represented the free acid of the ammonium salt. (author)

  17. Effect of Reactive Black 5 azo dye on soil processes related to C and N cycling

    Directory of Open Access Journals (Sweden)

    Khadeeja Rehman

    2018-05-01

    Full Text Available Azo dyes are one of the largest classes of synthetic dyes being used in textile industries. It has been reported that 15–50% of these dyes find their way into wastewater that is often used for irrigation purpose in developing countries. The effect of azo dyes contamination on soil nitrogen (N has been studied previously. However, how does the azo dye contamination affect soil carbon (C cycling is unknown. Therefore, we assessed the effect of azo dye contamination (Reactive Black 5, 30 mg kg−1 dry soil, bacteria that decolorize this dye and dye + bacteria in the presence or absence of maize leaf litter on soil respiration, soil inorganic N and microbial biomass. We found that dye contamination did not induce any change in soil respiration, soil microbial biomass or soil inorganic N availability (P > 0.05. Litter evidently increased soil respiration. Our study concludes that the Reactive Black 5 azo dye (applied in low amount, i.e., 30 mg kg−1 dry soil contamination did not modify organic matter decomposition, N mineralization and microbial biomass in a silty loam soil.

  18. Assessing PAH removal from clayey soil by means of electro-osmosis and electrodialysis

    KAUST Repository

    Lima, Ana T.

    2012-10-01

    Polycyclic aromatic hydrocarbons (PAH) are persistent and toxic contaminants which are difficult to remove from fine porous material like clayey soils. The present work aims at studying two electroremediation techniques for the removal of PAHs from a spiked natural silt soil from Saudi Arabia and a silty loam soil from The Netherlands which has been exposed to tar contamination for over 100. years. The two techniques at focus are electro-osmosis and electrodialysis. The latter is applied for the first time for the removal of PAH. The efficiency of the techniques is studied using these two soils, having been subjected to different PAH contact times. Two surfactants were used: the non-ionic surfactant Tween 80 and anionic surfactant sodium dodecyl sulphate (SDS) to aid desorption of PAHs from the soil. Results show a large discrepancy in the removal rates between spiked soil and long-term field contaminated soil, as expected. In spiked soil, electro-osmosis achieves up to 85% while electrodialysis accomplishes 68% PAH removal. In field contaminated soil, electro-osmosis results in 35% PAH removal whereas electrodialysis results in 79%. Short recommendations are derived for the up-scale of the two techniques. © 2012.

  19. Evaluation of the mobility and pollution index of selected essential/toxic metals in paddy soil by sequential extraction method.

    Science.gov (United States)

    Hasan, Maria; Kausar, Dilshad; Akhter, Gulraiz; Shah, Munir H

    2018-01-01

    Comparative distribution and mobility of selected essential and toxic metals in the paddy soil from district Sargodha, Pakistan was evaluated by the modified Community Bureau of Reference (mBCR) sequential extraction procedure. Most of the soil samples showed slightly alkaline nature while the soil texture was predominantly silty loam in nature. The metal contents were quantified in the exchangeable, reducible, oxidisable and residual fractions of the soil by flame atomic absorption spectrophotometry and the metal data were subjected to the statistical analyses in order to evaluate the mutual relationships among the metals in each fraction. Among the metals, Ca, Sr and Mn were found to be more mobile in the soil. A number of significant correlations between different metal pairs were noted in various fractions. Contamination factor, geoaccumulation index and enrichment factor revealed extremely severe enrichment/contamination for Cd; moderate to significant enrichment/contamination for Ni, Zn, Co and Pb while Cr, Sr, Cu and Mn revealed minimal to moderate contamination and accumulation in the soil. Multivariate cluster analysis showed significant anthropogenic intrusions of the metals in various fractions. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Nutrient Concentrations of Bush Bean (Phaseolus vulgaris L. and Potato (Solanum tuberosum L. Cultivated in Subarctic Soils Managed with Intercropping and Willow (Salix spp. Agroforestry

    Directory of Open Access Journals (Sweden)

    Meaghan J. Wilton

    2017-12-01

    Full Text Available To ease food insecurities in northern Canada, some remote communities started gardening initiatives to gain more access to locally grown foods. Bush beans (Phaseolus vulgaris L. and potatoes (Solanum tuberosum L. were assessed for N, P, K, Mg, and Ca concentrations of foliage as indicators of plant nutrition in a calcareous silty loam soil of northern Ontario James Bay lowlands. Crops were grown in sole cropping and intercropping configurations, with comparisons made between an open field and an agroforestry site enclosed with willow (Salix spp. trees. Foliage chemical analysis of the sites revealed an abundance of Ca, adequacies for Mg and N, and deficiencies in P and K. Intercropping bean and potato did not show significant crop–crop facilitation for nutrients. The agroforestry site showed to be a superior management practice for the James Bay lowland region, specifically for P. The agroforestry site had significantly greater P for bean plant (p = 0.024 and potato foliage (p = 0.002 compared to the open site. It is suspected that the presence of willows improve plant available P to bean and potatoes by tree root—crop root interactions and microclimate enhancements.

  1. Rate of loss of simazine, terbuthylazine, isoproturon, and methabenzthiazuron during soil solarization.

    Science.gov (United States)

    Navarro, Simón; Bermejo, Salvador; Vela, Nuria; Hernández, Joaquín

    2009-07-22

    This paper reports the use of solar heating by polyethylene mulching for decontamination of a silty clay-loam soil polluted with herbicides. Soil solarization, a natural and hydrothermal method commonly used for disinfesting soils, was tested during the summer season on a Hipercalcic Calcisol located in Murcia (southeast Spain) for dissipation of s-triazine (simazine and terbuthylazine) and phenylurea (isoproturon and methabenzthiazuron) herbicides using low-density (LD) and high-density (HD) polyethylene (PE) film as a cover. A well-established influence of the film was observed on the dissipation of all herbicides from the soil, although the density (0.92-0.95 g/cm(3)) of the film used (LDPE and HDPE) was not significant in terms of the rate of loss. In all cases, a quick depletion during the first 2 weeks was observed, mainly for terbuthylazine. The first-order model satisfactorily explained the dissipation process, but the Hoerl and biexponential equations were more appropriate, mainly for simazine, isoproturon, and methabenzthiazuron. In all cases, herbicides disappeared at faster rates in solarized soils (DT(50) = 4-29 days) than in nonmulched soils (DT(50) = 11-35 days), especially for terbuthylazine and isoproturon.

  2. Assessing PAH removal from clayey soil by means of electro-osmosis and electrodialysis

    KAUST Repository

    Lima, Ana T.; Ottosen, Lisbeth M.; Heister, Katja; Loch, J.P. Gustav

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAH) are persistent and toxic contaminants which are difficult to remove from fine porous material like clayey soils. The present work aims at studying two electroremediation techniques for the removal of PAHs from a spiked natural silt soil from Saudi Arabia and a silty loam soil from The Netherlands which has been exposed to tar contamination for over 100. years. The two techniques at focus are electro-osmosis and electrodialysis. The latter is applied for the first time for the removal of PAH. The efficiency of the techniques is studied using these two soils, having been subjected to different PAH contact times. Two surfactants were used: the non-ionic surfactant Tween 80 and anionic surfactant sodium dodecyl sulphate (SDS) to aid desorption of PAHs from the soil. Results show a large discrepancy in the removal rates between spiked soil and long-term field contaminated soil, as expected. In spiked soil, electro-osmosis achieves up to 85% while electrodialysis accomplishes 68% PAH removal. In field contaminated soil, electro-osmosis results in 35% PAH removal whereas electrodialysis results in 79%. Short recommendations are derived for the up-scale of the two techniques. © 2012.

  3. Impacts of soil conditioners and water table management on phosphorus loss in tile drainage from a clay loam soil.

    Science.gov (United States)

    Zhang, T Q; Tan, C S; Zheng, Z M; Welacky, T W; Reynolds, W D

    2015-03-01

    Adoption of waste-derived soil conditioners and refined water management can improve soil physical quality and crop productivity of fine-textured soils. However, the impacts of these practices on water quality must be assessed to ensure environmental sustainability. We conducted a study to determine phosphorus (P) loss in tile drainage as affected by two types of soil conditioners (yard waste compost and swine manure compost) and water table management (free drainage and controlled drainage with subirrigation) in a clay loam soil under corn-soybean rotation in a 4-yr period from 1999 to 2003. Tile drainage flows were monitored and sampled on a year-round continuous basis using on-site auto-sampling systems. Water samples were analyzed for dissolved reactive P (DRP), particulate P (PP), and total P (TP). Substantially greater concentrations and losses of DRP, PP, and TP occurred with swine manure compost than with control and yard waste compost regardless of water table management. Compared with free drainage, controlled drainage with subirrigation was an effective way to reduce annual and cumulative losses of DRP, PP, and TP in tile drainage through reductions in flow volume and P concentration with control and yard waste compost but not with swine manure compost. Both DRP and TP concentrations in tile drainage were well above the water quality guideline for P, affirming that subsurface loss of P from fine-textured soils can be one critical source for freshwater eutrophication. Swine manure compost applied as a soil conditioner must be optimized by taking water quality impacts into consideration. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  4. Radiological aspects of choice of a system of cultivation of sod-podzolic sandy loam soils with different degree of humidity on lands of Mogilev region contaminated with 137Cs

    International Nuclear Information System (INIS)

    Lazarevich, S.S.; Ermolenko, A.V.; Shapsheeva, T.P.

    2010-01-01

    In the conditions of the Republic of Belarus there were presented data about the influence of technological factors on entry of 137Cs into plant products (grain and green mass). In course of the study there were analyzed the following variants of soil cultivation: moldboard plowing; subsurface chisel soil tillage; subsurface surface soil tillage; minimal tillage. There were presented data on specific activity of 137Cs in plant product samples of oat (Avena sativa) grain; field pea (Pisum arvense L.) and oat mixture grain and green mass; wheat (Triticum aestivum) grain. There were determined the main principles of influence of cultivation systems of sod-podzolic sandy loam soil with different degree of humidity on transition of 137Cs into plants depending on the degree of soil and crop humidity. On the automorphic soil there was revealed a tendency of increased transition of 137Cs into grain and green mass after application of subsurface surface soil tillage system

  5. 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

    Directory of Open Access Journals (Sweden)

    A. D. Chukalla

    2017-07-01

    Full Text Available 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

  6. 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

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    2011-01-01

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

  8. Hibiscus sabdariffa L

    African Journals Online (AJOL)

    TEKWA IJASINI JOHN

    P application increased K and Mg, but reduced Ca contents of shoots. Application of P did ... of natural coloring and flavoring agent in food and fruit processing industries (Mc Clintock, 2004). The seeds .... loam. Loam. Sandy loam Clay loam.

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

    Science.gov (United States)

    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.

  10. Vegetative biomass predicts inflorescence production along a CO2 concentration gradient in mesic grassland

    Science.gov (United States)

    Fay, P. A.; Collins, H.; Polley, W.

    2016-12-01

    Atmospheric CO2 concentration will likely exceed 500 µL L-1 by 2050, often increasing plant community productivity in part by increasing abundance of species favored by increased CA . Whether increased abundance translates to increased inflorescence production is poorly understood, and is important because it indicates the potential effects of CO2 enrichment on genetic variability and the potential for evolutionary change in future generations. We examined whether the responses of inflorescence production to CO2 enrichment in four C4 grasses and a C3 forb were predicted their vegetative biomass, and by soil moisture, soil nitrogen, or light availability. Inflorescence production was studied in a long-term CO2 concentration gradient spanning pre-industrial to anticipated mid-21st century values (250 - 500 µL L-1) maintained on clay, silty clay and sandy loam soils common in the U.S. Southern Plains. We expected that CO2 enrichment would increase inflorescence production, and more so with higher water, nitrogen, or light availability. However, structural equation modeling revealed that vegetative biomass was the single consistent direct predictor of flowering for all species (p grass) and Solidago canadensis (C3 forb), direct CO2 effects on flowering were only weakly mediated by indirect effects of soil water content and soil NO3-N availability. For the decreasing species (Bouteloua curtipendula, C4 grass), the negative CO2-flowering relationship was cancelled (p = 0.39) by indirect effects of increased SWC and NO3-N on clay and silty clay soils. For the species with no CO2 response, inflorescence production was predicted only by direct water content (p grass) or vegetative biomass (p = 0.0009, Tridens albescens, C4 grass) effects. Light availability was unrelated to inflorescence production. Changes in inflorescence production are thus closely tied to direct and indirect effects of CO2 enrichment on vegetative biomass, and may either increase, decrease, or leave

  11. Seismic Response to Sonic Boom-Coupled Rayleigh Waves

    Science.gov (United States)

    1990-06-28

    side slopes and moderately deep well-drained, gently sloping to moderately steep soils on terraces; Ann. Rainfall--10" to 16") Cath-Timpahute- Jarab ...slopes less than 15%, and Alluvial land) Jarab Series (cobbley loam, gravelly loam, gravelly clay loam, pan fragments, hardpan with silica laminae...weakly and strongly cemented with lime, soft, calcareous gravelly loam: al!-aline, calcareous) Jarab cobbley loam, 2 to 15% slopes, (JCD) (moderately

  12. SSEM: A model for simulating runoff and erosion of saline-sodic soil slopes under coastal reclamation

    Science.gov (United States)

    Liu, Dongdong; She, Dongli

    2018-06-01

    Current physically based erosion models do not carefully consider the dynamic variations of soil properties during rainfall and are unable to simulate saline-sodic soil slope erosion processes. The aim of this work was to build upon a complete model framework, SSEM, to simulate runoff and erosion processes for saline-sodic soils by coupling dynamic saturated hydraulic conductivity Ks and soil erodibility Kτ. Sixty rainfall simulation rainfall experiments (2 soil textures × 5 sodicity levels × 2 slope gradients × 3 duplicates) provided data for model calibration and validation. SSEM worked very well for simulating the runoff and erosion processes of saline-sodic silty clay. The runoff and erosion processes of saline-sodic silt loam were more complex than those of non-saline soils or soils with higher clay contents; thus, SSEM did not perform very well for some validation events. We further examined the model performances of four concepts: Dynamic Ks and Kτ (Case 1, SSEM), Dynamic Ks and Constant Kτ (Case 2), Constant Ks and Dynamic Kτ (Case 3) and Constant Ks and Constant Kτ (Case 4). The results demonstrated that the model, which considers dynamic variations in soil saturated hydraulic conductivity and soil erodibility, can provide more reasonable runoff and erosion prediction results for saline-sodic soils.

  13. Plasticity and density-moisture-resistance relations of soils amended with fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Mapfuno, E.; Chanasyk, D.S. [University of Alberta, Edmonton, AB (Canada). Dept. of Renewable Resources

    1998-06-01

    The objective of this study was to investigate the impact of fly ash amendments on the plasticity, water retention and penetration resistance-density-moisture relationships of three soils of sandy loam, loam and clay loam textures in order to determine the potential compaction of these soil/fly ash mixtures if they were worked at different moisture ranges. For all three soils the addition of fly ash decreased the plasticity index, but slightly increased the Proctor maximum density. This implies that fly ash amendments reduce the range of moisture within which soils are most susceptible to compaction. However, for the sandy loam and loam textured soils amended with fly ash, cultivation must be avoided at moisture contents close to field capacity since maximum densification occurs at these moisture contents. In all three soils the addition of fly ash increased water retention, especially in the sandy loam. Fly ash amendments increased penetration resistance of the clay loam, but increased penetration resistance of the sandy loam.

  14. Green and blue water footprint reduction in irrigated agriculture: effect of irrigation techniques, irrigation strategies and mulching

    Science.gov (United States)

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

    2015-12-01

    Consumptive water footprint (WF) reduction in irrigated crop production is essential given the increasing competition for freshwater. This study explores the effect of three management practices on the soil water balance and plant growth, specifically on evapotranspiration (ET) and yield (Y) and thus the consumptive WF of crops (ET / Y). The management practices are four irrigation techniques (furrow, sprinkler, drip and subsurface drip (SSD)), four irrigation strategies (full (FI), deficit (DI), supplementary (SI) and no irrigation), and three mulching practices (no mulching, organic (OML) and synthetic (SML) mulching). Various cases were considered: arid, semi-arid, sub-humid and humid environments in Israel, Spain, Italy and the UK, respectively; wet, normal and dry years; three soil types (sand, sandy loam and silty clay loam); and three crops (maize, potato and tomato). The AquaCrop model and the global WF accounting standard were used to relate the management practices to effects on ET, Y and WF. For each management practice, the associated green, blue and total consumptive WF were compared to the reference case (furrow irrigation, full irrigation, no mulching). The average reduction in the consumptive WF is 8-10 % if we change from the reference to drip or SSD, 13 % when changing to OML, 17-18 % when moving to drip or SSD in combination with OML, and 28 % for drip or SSD in combination with SML. All before-mentioned reductions increase by one or a few per cent when moving from full to deficit irrigation. Reduction in overall consumptive WF always goes together with an increasing ratio of green to blue WF. The WF of growing a crop for a particular environment is smallest under DI, followed by FI, SI and rain-fed. Growing crops with sprinkler irrigation has the largest consumptive WF, followed by furrow, drip and SSD. Furrow irrigation has a smaller consumptive WF compared with sprinkler, even though the classical measure of "irrigation efficiency" for furrow

  15. Characterization of lacustrine shale pore structure: The Upper-Triassic Yanchang Formation, Ordos Basin, China

    Directory of Open Access Journals (Sweden)

    Yuxi Yu

    2016-08-01

    Full Text Available Amounts of silty laminae in continental shale gas reservoir were investigated in the Zhangjiatan shale of the Yanchang Formation, Ordos Basin. The purpose of this study is to provide awareness in terms of the nature and discrepancies in pore structure between silty laminae and clayey laminae. By mechanically separating the silty laminae from the shale core, a combination measurement series of mercury injection capillary pressure, N2 adsorption, and carbon dioxide adsorption were performed on the aforementioned two parts. An integrated pore size distribution, with a pore diameter range of 0.1 nm-100 μm, was obtained by using appropriate sample particle size and calculation model. The comparative analysis of the pore structure shows that the clayey laminae are dominated by mesopore and micropore; meanwhile, the silty laminae are dominated by macropore alone. The pore volume distribution in clayey laminae is sorted as mesopore volume > micropore volume > macropore volume, on the other hand, for silty laminae it is macropore volume > mesopore volume > micropore volume. The averaged total pore volume of silty laminae is 2.02 cc/100 g, and for clayey laminae, it is 1.41 cc/100 g. The porosity of silty laminae is 5.40%, which is greater than that of clayey laminae's 3.67%. Since silty laminae have larger pore width and pore space, they are more permeable and porous than the clayey laminae; it also acts as a favorable conduit and reservoir for shale gas.

  16. The influence of reduced tillage on water regime and nutrient leaching in a loamy soil

    OpenAIRE

    Baigys, Giedrius; Gaigalis, Kazimieras; Kutra, Ginutis

    2006-01-01

    The effect of tillage technologies and terms on soil moisture regime and nitrate leaching was studied in field trials carried out on 0.76-1.36-ha fields. The study site was arranged in Pikeliai village (Kėdainiai district). The soil prevailing in the study site is Endocalcari - Endohypogleic Cambisol, sandy light loam and sandy loam on deeper layers of sandy loam and sandy light loam. The arable horizon contains sandy light loam, which is characteristic of the soils prevailing in the Middle L...

  17. Nitrogen availability and indirect measurements of greenhouse gas emissions from aerobic and anaerobic biowaste digestates applied to agricultural soils

    International Nuclear Information System (INIS)

    Rigby, H.; Smith, S.R.

    2013-01-01

    Highlights: • Nitrogen release in digestate-amended soil depends on the digestate type. • Overall N release is modulated by digestate mineral and mineralisable N contents. • Microbial immobilisation does not influence overall release of digestate N in soil. • Digestate physical properties and soil type interact to affect overall N recovery. • High labile C inputs in digestate may promote denitrification in fine-textured soil. - Abstract: Recycling biowaste digestates on agricultural land diverts biodegradable waste from landfill disposal and represents a sustainable source of nutrients and organic matter (OM) to improve soil for crop production. However, the dynamics of nitrogen (N) release from these organic N sources must be determined to optimise their fertiliser value and management. This laboratory incubation experiment examined the effects of digestate type (aerobic and anaerobic), waste type (industrial, agricultural and municipal solid waste or sewage sludge) and soil type (sandy loam, sandy silt loam and silty clay) on N availability in digestate-amended soils and also quantified the extent and significance of the immobilisation of N within the soil microbial biomass, as a possible regulatory mechanism of N release. The digestate types examined included: dewatered, anaerobically digested biosolids (DMAD); dewatered, anaerobic mesophilic digestate from the organic fraction of municipal solid waste (DMADMSW); liquid, anaerobic co-digestate of food and animal slurry (LcoMAD) and liquid, thermophilic aerobic digestate of food waste (LTAD). Ammonium chloride (NH 4 Cl) was included as a reference treatment for mineral N. After 48 days, the final, maximum net recoveries of mineral N relative to the total N (TN) addition in the different digestates and unamended control treatments were in the decreasing order: LcoMAD, 68%; LTAD, 37%, DMAD, 20%; and DMADMSW, 11%. A transient increase in microbial biomass N (MBN) was observed with LTAD application

  18. Nitrogen availability and indirect measurements of greenhouse gas emissions from aerobic and anaerobic biowaste digestates applied to agricultural soils

    Energy Technology Data Exchange (ETDEWEB)

    Rigby, H.; Smith, S.R., E-mail: s.r.smith@imperial.ac.uk

    2013-12-15

    Highlights: • Nitrogen release in digestate-amended soil depends on the digestate type. • Overall N release is modulated by digestate mineral and mineralisable N contents. • Microbial immobilisation does not influence overall release of digestate N in soil. • Digestate physical properties and soil type interact to affect overall N recovery. • High labile C inputs in digestate may promote denitrification in fine-textured soil. - Abstract: Recycling biowaste digestates on agricultural land diverts biodegradable waste from landfill disposal and represents a sustainable source of nutrients and organic matter (OM) to improve soil for crop production. However, the dynamics of nitrogen (N) release from these organic N sources must be determined to optimise their fertiliser value and management. This laboratory incubation experiment examined the effects of digestate type (aerobic and anaerobic), waste type (industrial, agricultural and municipal solid waste or sewage sludge) and soil type (sandy loam, sandy silt loam and silty clay) on N availability in digestate-amended soils and also quantified the extent and significance of the immobilisation of N within the soil microbial biomass, as a possible regulatory mechanism of N release. The digestate types examined included: dewatered, anaerobically digested biosolids (DMAD); dewatered, anaerobic mesophilic digestate from the organic fraction of municipal solid waste (DMADMSW); liquid, anaerobic co-digestate of food and animal slurry (LcoMAD) and liquid, thermophilic aerobic digestate of food waste (LTAD). Ammonium chloride (NH{sub 4}Cl) was included as a reference treatment for mineral N. After 48 days, the final, maximum net recoveries of mineral N relative to the total N (TN) addition in the different digestates and unamended control treatments were in the decreasing order: LcoMAD, 68%; LTAD, 37%, DMAD, 20%; and DMADMSW, 11%. A transient increase in microbial biomass N (MBN) was observed with LTAD application

  19. Microbial functional diversity responses to 2 years since biochar application in silt-loam soils on the Loess Plateau.

    Science.gov (United States)

    Zhu, Li-Xia; Xiao, Qian; Shen, Yu-Fang; Li, Shi-Qing

    2017-10-01

    The structure and function of soil microbial communities have been widely used as indicators of soil quality and fertility. The effect of biochar application on carbon sequestration has been studied, but the effect on soil microbial functional diversity has received little attention. We evaluated effects of biochar application on the functional diversities of microbes in a loam soil. The effects of biochar on microbial activities and related processes in the 0-10 and 10-20cm soil layers were determined in a two-year experiment in maize field on the Loess Plateau in China. Low-pyrolysis biochar produced from maize straw was applied into soils at rates of 0 (BC0), 10 (BC10) and 30 (BC30)tha -1 . Chemical analysis indicated that the biochar did not change the pH, significantly increased the amounts of organic carbon and nitrogen, and decreased the amount of mineral nitrogen and the microbial quotient. The biochar significantly decreased average well colour development (AWCD) values in Biolog EcoPlates™ for both layers, particularly for the rate of 10tha -1 . Biochar addition significantly decreased substrate richness (S) except for BC30 in the 0-10cm layer. Effects of biochar on the Shannon-Wiener index (H) and Simpson's dominance (D) were not significant, except for a significant increase in evenness index (E) in BC10 in the 10-20cm layer. A principal component analysis clearly differentiated the treatments, and microbial use of six categories of substrates significantly decreased in both layers after biochar addition, although the use of amines and amides did not differ amongst the three treatments in the deeper layer. Maize above ground dry biomass and height did not differ significantly amongst the treatments, and biochar had no significant effect on nitrogen uptake by maize seedlings. H was positively correlated with AWCD, and negatively with pH. AWCD was positively correlated with mineral N and negatively with pH. Our results indicated that shifts in soil

  20. The Effect of Zeolite on Aggregate Stability Indices

    Directory of Open Access Journals (Sweden)

    F. Sohrab

    2016-02-01

    , after preparation of two different types of soil with light and medium texture and doing identification tests such as determination of gradation and hydrometer tests and Atterberg limits, zeolite in four levels, 0 (control, 1%, 5%, and 10%w/w, was mixed with two soil textures (sandy loam and silty loam in three replications. Then, each treatment was saturated for 48 hours in each month, during 6 months. Dry soil aggregate stability (Mean Weight Diameter (MWD, Geometric Mean Diameter (GMD, and Wet Aggregate Stability (WAS, were determined. The experiment was carried out using factorial method in a randomized complete design. Results and Discussion:The results showed that, in sandy loam texture, there was no significant difference between two types of zeolites, their level of using and their interaction on MWD (p

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

    Science.gov (United States)

    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

  2. Physical-hydraulic properties of a sandy loam typic paleudalf soil under organic cultivation of 'montenegrina' mandarin (Citrus deliciosa Tenore¹

    Directory of Open Access Journals (Sweden)

    Caroline Valverde dos Santos

    2014-12-01

    Full Text Available Citrus plants are the most important fruit species in the world, with emphasis to oranges, mandarins and lemons. In Rio Grande do Sul, Brazil, most fruit production is found on small properties under organic cultivation. Soil compaction is one of the factors limiting production and due to the fixed row placement of this crop, compaction can arise in various manners in the interrows of the orchard. The aim of this study was to evaluate soil physical properties and water infiltration capacity in response to interrow management in an orchard of mandarin (Citrus deliciosa Tenore 'Montenegrina' under organic cultivation. Interrow management was performed through harrowing, logs in em "V", mowing, and cutting/knocking down plants with a knife roller. Soil physical properties were evaluated in the wheel tracks of the tractor (WT, between the wheel tracks (BWT, and in the area under the line projection of the canopy (CLP, with undisturbed soil samples collected in the 0.00-0.15, 0.15-0.30, 0.30-0.45, and 0.45-0.60 m layers, with four replicates. The soil water infiltration test was performed using the concentric cylinder method, with a maximum time of 90 min for each test. In general, soil analysis showed a variation in the physical-hydraulic properties of the Argissolo Vermelho-Amarelo distrófico arênico (sandy loam Typic Paleudalf in the three sampling sites in all layers, regardless of the management procedure in the interrows. Machinery traffic leads to heterogeneity in the soil physical-hydraulic properties in the interrows of the orchard. Soil porosity and bulk density are affected especially in the wheel tracks of the tractor (WT, which causes a reduction in the constant rate of infiltration and in the accumulated infiltration of water in this sampling site. The use of the disk harrow and mower leads to greater harmful effects on the soil, which can interfere with mandarin production.

  3. Environmental Assessment, Repair of the Dam at Non-Potable Reservoir #1, United States Air Force Academy, Colorado

    Science.gov (United States)

    2015-08-01

    expected and are not analyzed further in this EA. Utilities. The electrical, natural gas, water, and sanitary sewer requirements of the Proposed...therefore, no increase in utility usage or sanitary and solid waste generation would occur. Utility connections that run alongside the existing dam...for evaluation of the soils suitability for native revegetation. An acceptable topsoil shall have a loam, sandy loam, clay loam, or silt loam texture

  4. Nitrogen Fertilizer Rate and Crop Management Effects on Nitrate Leaching from an Agricultural Field in Central Pennsylvania

    Directory of Open Access Journals (Sweden)

    Richard H. Fox

    2001-01-01

    Full Text Available Eighteen pan lysimeters were installed at a depth of 1.2 m in a Hagerstown silt loam soil in a corn field in central Pennsylvania in 1988. In 1995, wick lysimeters were also installed at 1.2 m depth in the same access pits. Treatments have included N fertilizer rates, use of manure, crop rotation (continuous corn, corn-soybean, alfalfa-corn, and tillage (chisel plow-disk, no-till. The leachate data were used to evaluate a number of nitrate leaching models. Some of the highlights of the 11 years of results include the following: 1 growing corn without organic N inputs at the economic optimum N rate (EON resulted in NO3–-N concentrations of 15 to 20 mg l-1 in leachate; 2 use of manure or previous alfalfa crop as partial source of N also resulted in 15 to 20 mg l-1 of NO3–-N in leachate below corn at EON; 3 NO3–-N concentration in leachate below alfalfa was approximately 4 mg l-1; 4 NO3–-N concentration in leachate below soybeans following corn was influenced by fertilizer N rate applied to corn; 5 the mass of NO3–-N leached below corn at the EON rate averaged 90 kg N ha-1 (approx. 40% of fertilizer N applied at EON; 6 wick lysimeters collected approximately 100% of leachate vs. 40–50% collected by pan lysimeters. Coefficients of variation of the collected leachate volumes for both lysimeter types were similar; 7 tillage did not markedly affect nitrate leaching losses; 8 tested leaching models could accurately predict leachate volumes and could be calibrated to match nitrate leaching losses in calibration years, but only one model (SOILN accurately predicted nitrate leaching losses in the majority of validation treatment years. Apparent problems with tested models: there was difficulty estimating sizes of organic N pools and their transformation rates, and the models either did not include a macropore flow component or did not handle macropore flow well.

  5. Comparison of pore water samplers and cryogenic distillation under laboratory and field conditions for soil water stable isotope analysis.

    Science.gov (United States)

    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).

  6. Infiltration into cropped soils: effect of rain and sodium adsorption ratio-impacted irrigation water.

    Science.gov (United States)

    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.

  7. Decaffeination process characteristic of Robusta coffee in single column reactor using ethyl acetate solvent

    Directory of Open Access Journals (Sweden)

    Sukrisno Widyotomo

    2009-08-01

    Full Text Available AbstractThis experiment aims to know the solar energy efficiency of four clones of cocoa that cultivated under three different shading plants. This experiment has been done from September until December 2013 located at Kaliwining Experiment Farm with characteristic 45 m above sea level, soil type is low humic gley, soil texture is silty clay loam, and climate classification type D based on Scmidht and Fergusson Classification. This experiment used Nested Design as Experimental Design with species of shading plant as main plot which are Teak (Tectona grandis L., Krete (Cassia surattensis (Burm. F., Lamtoro (Leucaena leucocephala L. and Cocoa clones as sub plot which are Sulawesi 1, Sulawesi 2, KKM 22, KW 165. The observation of solar energy efficiency consists of daily solar radiation intensity, solar radiation intensity above plant, solar radiation intensity under plant, and also plant total dry weight. The experimental result showed that there is differences (heterogenity between shading location based on homogenity test by Bartlett Method. There are some interaction between the kind of shading plant and clones in parameter of interception efficiency, absorbtion efficiency, the efficiency of solar energy that caught by plant, and solar energy conversion efficiency. The efficiency of solar energy that caught by plant will affect the solar energy conversion efficiency with R2 = 0,86.  Keywords : Solar Energy Efficiency, Cocoa Clones, Shading Plant, Nested Design, Bartlett Method

  8. Water retention and availability in soils of the State of Santa Catarina-Brazil: effect of textural classes, soil classes and lithology

    Directory of Open Access Journals (Sweden)

    André da Costa

    2013-12-01

    Full Text Available The retention and availability of water in the soil vary according to the soil characteristics and determine plant growth. Thus, the aim of this study was to evaluate water retention and availability in the soils of the State of Santa Catarina, Brazil, according to the textural class, soil class and lithology. The surface and subsurface horizons of 44 profiles were sampled in different regions of the State and different cover crops to determine field capacity, permanent wilting point, available water content, particle size, and organic matter content. Water retention and availability between the horizons were compared in a mixed model, considering the textural classes, the soil classes and lithology as fixed factors and profiles as random factors. It may be concluded that water retention is greater in silty or clayey soils and that the organic matter content is higher, especially in Humic Cambisols, Nitisols and Ferralsol developed from igneous or sedimentary rocks. Water availability is greater in loam-textured soils, with high organic matter content, especially in soils of humic character. It is lower in the sandy texture class, especially in Arenosols formed from recent alluvial deposits or in gravelly soils derived from granite. The greater water availability in the surface horizons, with more organic matter than in the subsurface layers, illustrates the importance of organic matter for water retention and availability.

  9. Solar energy efficiency of cocoa clones cultivated under three species of shade trees.

    Directory of Open Access Journals (Sweden)

    Oscar Regazzoni

    2015-04-01

    Full Text Available This experiment aims to know the solar energy efficiency of four clones of cocoa that cultivated under three different shading plants. This experiment has been done from September until December 2013 located at Kaliwining Experiment Farm with characteristic 45 m above sea level, soil type is low humic gley, soil texture is silty clay loam, and climate classification type D based on Scmidht and Fergusson Classification. This experiment used Nested Design as Experimental Design with species of shading plant as main plot which are Teak (Tectona grandis L., Krete (Cassia surattensis (Burm. F., Lamtoro (Leucaena leucocephala L. and Cocoa clones as sub plot which are Sulawesi 1, Sulawesi 2, KKM 22, KW 165. The observation of solar energy efficiency consists of daily solar radiation intensity, solar radiation intensity above plant, solar radiation intensity under plant, and also plant total dry weight. The experimental result showed that there is differences (heterogenity between shading location based on homogenity test by Bartlett Method. There are some interaction between the kind of shading plant and clones in parameter of interception efficiency, absorbtion efficiency, the efficiency of solar energy that caught by plant, and solar energy conversion efficiency. The efficiency of solar energy that caught by plant will affect the solar energy conversion efficiency with R2 = 0,86.

  10. Submerged pedology: the soils of minor islands in the Venice lagoon

    Directory of Open Access Journals (Sweden)

    Mohammad Washa

    2015-12-01

    Full Text Available Minor islands of the Venice lagoon are part of a delicate ecosystem, with equilibrium that depends on multiple factors deriving from both the aqueous and the terrestrial compartment, and represent useful indicators of the lagoon ecosystem status. Over centuries, some islands emerged, some others disappeared, others are being submerged in consequence of sea level rise, or are dismantled by marine erosion. Ecological survey and soil sampling evidenced rather homogeneous environment and soil characters, likely due to the same genesis from HTM during centuries, and to environmental conditions such as moisture and brackish groundwater. Four of the examined soils are Inceptisols, while the others present limited horizon differentiation, and are Entisols. All the profiles reflect udic or aquic conditions, and some of them are submerged for most time. Most soils are moderately alkaline (7.9 250 g/kg; organic carbon content at surface is within the normal range (8 17 g/kg and carbonates. Moreover, the textural class is generally silty-loam with increasing clay content with depth. Currently, the soils examined present hydromorphic pedofeatures, which are the result of the most important pedogenic process in the lagoon. Alternating reduction/oxidation processes would increase as a consequence of sea level rise, determining reducing conditions at bottom, and conversely enhancing salt concentration uppermost, with negative consequences for both pedogenic evolution and vegetation survival.

  11. Level of Coffee Consumption in Urban Community and Its Determinant Factors: Case Study in Jember District

    Directory of Open Access Journals (Sweden)

    Endang Wiji Lestari

    2009-12-01

    Full Text Available AbstractThis experiment aims to know the solar energy efficiency of four clones of cocoa that cultivated under three different shading plants. This experiment has been done from September until December 2013 located at Kaliwining Experiment Farm with characteristic 45 m above sea level, soil type is low humic gley, soil texture is silty clay loam, and climate classification type D based on Scmidht and Fergusson Classification. This experiment used Nested Design as Experimental Design with species of shading plant as main plot which are Teak (Tectona grandis L., Krete (Cassia surattensis (Burm. F., Lamtoro (Leucaena leucocephala L. and Cocoa clones as sub plot which are Sulawesi 1, Sulawesi 2, KKM 22, KW 165. The observation of solar energy efficiency consists of daily solar radiation intensity, solar radiation intensity above plant, solar radiation intensity under plant, and also plant total dry weight. The experimental result showed that there is differences (heterogenity between shading location based on homogenity test by Bartlett Method. There are some interaction between the kind of shading plant and clones in parameter of interception efficiency, absorbtion efficiency, the efficiency of solar energy that caught by plant, and solar energy conversion efficiency. The efficiency of solar energy that caught by plant will affect the solar energy conversion efficiency with R2 = 0,86.  Keywords : Solar Energy Efficiency, Cocoa Clones, Shading Plant, Nested Design, Bartlett Method

  12. Effect of different pre-sowing tillage on quantity and quality of parsnip (Pastinaca sativa L. root yield in ridge cultivation

    Directory of Open Access Journals (Sweden)

    Mirosław Konopiński

    2012-12-01

    Full Text Available Parsnip is a very valuable vegetable due to its nutritional value and dietetic quality. It is moreover herbal raw material abundant in active substances. The yield quality of vegetables greatly depends on thorough pre-sowing soil tillage. The present study aimed at evaluating the influence of different presowing soil tillage (medium-deep ploughing, cultivating and plant growing methods, flat or ridge cultivation, on the yield of parsnip and some biometric traits of its roots. The field experiment was carried out in 1999, 2000 and 2002 on lessive soil with the granulometric composition corresponding to medium silty loam. The parsnip cultivar 'Półdługi Biały' was the experimental plant species. The cultivation of parsnip on ridges had a significant influence on increased total yield of roots and decreased yield of small roots, as compared to flat cultivation. A significant increase in unit weight of the root and its diameter in the top part was also recorded in the latter type of cultivation. Spring pre-sowing tillage had no significant effect on parsnip yields. An increasing trend was observed only for total and marketable root yield in the ploughed plots. When parsnip is grown on lessive soil (which has an unstable structure, plants cultivated on ridges after spring pre-sowing plough are the most beneficial treatment combination.

  13. Side Effects of Nitrification Inhibitors on Non Target Microbial Processes in Soils

    Directory of Open Access Journals (Sweden)

    Johannes Carl Gottlieb Ottow

    2011-01-01

    Full Text Available Agricultural chemicals have been used extensively in modern agriculture and toxicological studies suggest a great potential for inducing undesirable effects on non target organisms. A model experiment was conducted in order to determine side effects of three nitrification inhibitors (NIs, 3,4dimethylpyrazolephosphate = DMPP, 4-Chlor-methylpyrazole phosphate = ClMPP and dicyandiamide = DCD on non target microbial processes in soils. Side effects and dose response curve of three NIs were quantified under laboratory conditions using silty clay, loam and a sandy soils. Dehydrogenase, dimethylsulfoxide reductase as well as nitrogenase activity (NA and potential denitrification capacity were measured as common and specific non target microbial processes. The influence of 5-1000 times the base concentration, dose response curves were examined, and no observable effect level = NOEL, as well as effective dose ED10 and ED50 (10% and 50% inhibition were calculated. The NOEL for microbial non target processes were about 30–70 times higher than base concentration in all investigated soils. The potential denitrification capacity revealed to be the most sensitive parameter. ClMPP exhibited the strongest influence on the non target microbial processes in the three soils. The NOEL, ED10 and ED50 values were higher in clay than in loamy or sandy soil. The NIs was the most effective in sandy soils.

  14. Migration of 137Cs and 90Sr in undisturbed soil profiles under controlled and close-to-real conditions

    International Nuclear Information System (INIS)

    Forsberg, S.; Rosen, K.; Fernandez, V.; Juhan, H.

    2000-01-01

    Migration of 137 Cs and 90 Sr in undisturbed soil was studied in large lysimeters three and four years after contamination, as part of a larger European project studying radionuclide soil-plant interactions. The lysimeters were installed in greenhouses with climate control and contaminated with radionuclides in an aerosol mixture, simulating fallout from a nuclear accident. The soil types studied were loam, silt loam, sandy loam and loamy sand. The soils were sampled to 30-40 cm depth in 1997 and 1998. The total deposition of 137 Cs ranged from 24 to 45 MBq/m 2 , and of 90 Sr from 23 to 52 MBq/m 2 . It was shown that migration of 137 Cs was fastest in sandy loam, and of 90 Sr fastest in sandy loam and loam. The slowest migration of both nuclides was found in loamy sand. Retention within the upper 5 cm was 60% for both 137 Cs and 90 Sr in sandy loam, while in loamy sand it was 97 and 96%, respectively. In 1998, migration rates, calculated as radionuclide weighted median depth (migration centre) divided by time since deposition were 1.1 cm/year for both 137 Cs and 90 Sr in sandy loam, 0.8 and 1.0 cm/year, respectively, in loam, 0.6 and 0.8 cm/year in silt loam, and 0.4 and 0.6 cm/year for 137 Cs and 90 Sr, respectively, in loamy sand. A distinction is made between short-term migration, caused by events soon after deposition and less affected by soil type, and long-term migration, more affected by e.g. soil texture. Three to four years after deposition, effects of short-term migration is still dominant in the studied soils

  15. Influence of salinity on bioremediation of oil in soil

    International Nuclear Information System (INIS)

    Rhykerd, R.L.; Weaver, R.W.; McInnes, K.J.

    1995-01-01

    Spills from oil production and processing result in soils being contaminated with oil and salt. The effect of NaCl on degradation of oil in a sandy-clay loam and a clay loam soil was determined. Soils were treated with 50 g kg -1 non-detergent motor oil (30 SAE). Salt treatments included NaCl amendments to adjust the soil solution electrical conductivities to 40, 120, and 200 dS m -1 . Soils were amended with nutrients and incubated at 25 o C. Oil degradation was estimated from the quantities of CO 2 evolved and from gravimetric determinations of remaining oil. Salt concentrations of 200 dS m -1 in oil amended soils resulted in a decrease in oil mineralized by 44% for a clay loam and 20% for a sandy-clay loam soil. A salt concentration of 40 dS m -1 reduced oil mineralization by about 10% in both soils. Oil mineralized in the oil amended clay-loam soil was 2-3 times greater than for comparable treatments of the sandy-clay loam soil. Amending the sandy-clay loam soil with 5% by weight of the clay-loam soil enhanced oil mineralization by 40%. Removal of salts from oil and salt contaminated soils before undertaking bioremediation may reduce the time required for bioremediation. (author)

  16. Laboratory Study of the Influence of Substrate Type and Temperature on the Exploratory Tunneling by Formosan Subterranean Termite

    Directory of Open Access Journals (Sweden)

    Bal K. Gautam

    2012-06-01

    Full Text Available Using two-dimensional foraging arenas, laboratory tests were conducted to investigate the effect of soil type, soil moisture level and ambient temperature on the exploratory tunneling by Coptotermes formosanus Shiraki. In choice arenas consisting of two substrate types having two moisture levels each, and conducted at a constant temperature of 22 °C, a significantly greater proportion of termites aggregated in sand than in sandy loam. Similarly, the length of excavated tunnels was also increased in sand. In a given substrate, termite aggregation or tunnel length did not differ between 5% and 15% moisture levels. In no-choice tests, where three different substrates (sand, sandy loam and silt loam were tested at two temperatures (22 °C and 28 °C, excavations were significantly greater in sand than either sandy loam or silt loam at 22 °C. Fewer primary tunnels were constructed in sandy loam than in sand and fewer branched tunnels than either in sand or silt loam. No significant difference in either tunnel length or number of primary or branched tunnels was found between these two temperatures.

  17. Effect of nitrogen and water availability of three soil types on yield, radiation use efficiency and evapotranspiration in field-grown quinoa

    DEFF Research Database (Denmark)

    Razzaghi, Fatemeh; Plauborg, Finn; Jacobsen, Sven-Erik

    2012-01-01

    Quinoa (Chenopodium quinoa Willd.) is believed to be tolerant to abiotic stress including salinity, drought and poor soil quality. To investigate the effect of soil type and soil-drying during the seed-filling phase on N-uptake, yield and water use, a Danish-bred cultivar (cv. Titicaca) was grown...... in field lysimeters with sand, sandy loam and sandy clay loam soil. Despite application of the same amount of nitrogen (120 kg N ha−1) to all plots, there were large differences in crop nitrogen-uptake for sandy clay loam (134 kg ha−1), sandy loam (102 kg ha−1) and sand (77 kg ha−1) under full irrigation....... This lead to higher interception of photosynthetic active radiation and higher seed yield on sandy clay loam (3.3 Mg ha−1) and sandy loam (3.0 Mg ha−1) than on sand (2.3 Mg ha−1). The soil with higher clay content had also the highest transpiration, crop evapotranspiration and yield due to the higher uptake...

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

    Science.gov (United States)

    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...

  19. Shallow water table effects on water, sediment, and pesticide transport in vegetative filter strips - Part 2: model coupling, application, factor importance, and uncertainty

    Science.gov (United States)

    Lauvernet, Claire; Muñoz-Carpena, Rafael

    2018-01-01

    Vegetative filter strips are often used for protecting surface waters from pollution transferred by surface runoff in agricultural watersheds. In Europe, they are often prescribed along the stream banks, where a seasonal shallow water table (WT) could decrease the buffer zone efficiency. In spite of this potentially important effect, there are no systematic experimental or theoretical studies on the effect of this soil boundary condition on the VFS efficiency. In the companion paper (Muñoz-Carpena et al., 2018), we developed a physically based numerical algorithm (SWINGO) that allows the representation of soil infiltration with a shallow water table. Here we present the dynamic coupling of SWINGO with VFSMOD, an overland flow and transport mathematical model to study the WT influence on VFS efficiency in terms of reductions of overland flow, sediment, and pesticide transport. This new version of VFSMOD was applied to two contrasted benchmark field studies in France (sandy-loam soil in a Mediterranean semicontinental climate, and silty clay in a temperate oceanic climate), where limited testing of the model with field data on one of the sites showed promising results. The application showed that for the conditions of the studies, VFS efficiency decreases markedly when the water table is 0 to 1.5 m from the surface. In order to evaluate the relative importance of WT among other input factors controlling VFS efficiency, global sensitivity and uncertainty analysis (GSA) was applied on the benchmark studies. The most important factors found for VFS overland flow reduction were saturated hydraulic conductivity and WT depth, added to sediment characteristics and VFS dimensions for sediment and pesticide reductions. The relative importance of WT varied as a function of soil type (most important at the silty-clay soil) and hydraulic loading (rainfall + incoming runoff) at each site. The presence of WT introduced more complex responses dominated by strong interactions in

  20. Shallow water table effects on water, sediment, and pesticide transport in vegetative filter strips – Part 2: model coupling, application, factor importance, and uncertainty

    Directory of Open Access Journals (Sweden)

    C. Lauvernet

    2018-01-01

    Full Text Available Vegetative filter strips are often used for protecting surface waters from pollution transferred by surface runoff in agricultural watersheds. In Europe, they are often prescribed along the stream banks, where a seasonal shallow water table (WT could decrease the buffer zone efficiency. In spite of this potentially important effect, there are no systematic experimental or theoretical studies on the effect of this soil boundary condition on the VFS efficiency. In the companion paper (Muñoz-Carpena et al., 2018, we developed a physically based numerical algorithm (SWINGO that allows the representation of soil infiltration with a shallow water table. Here we present the dynamic coupling of SWINGO with VFSMOD, an overland flow and transport mathematical model to study the WT influence on VFS efficiency in terms of reductions of overland flow, sediment, and pesticide transport. This new version of VFSMOD was applied to two contrasted benchmark field studies in France (sandy-loam soil in a Mediterranean semicontinental climate, and silty clay in a temperate oceanic climate, where limited testing of the model with field data on one of the sites showed promising results. The application showed that for the conditions of the studies, VFS efficiency decreases markedly when the water table is 0 to 1.5 m from the surface. In order to evaluate the relative importance of WT among other input factors controlling VFS efficiency, global sensitivity and uncertainty analysis (GSA was applied on the benchmark studies. The most important factors found for VFS overland flow reduction were saturated hydraulic conductivity and WT depth, added to sediment characteristics and VFS dimensions for sediment and pesticide reductions. The relative importance of WT varied as a function of soil type (most important at the silty-clay soil and hydraulic loading (rainfall + incoming runoff at each site. The presence of WT introduced more complex responses dominated by strong

  1. Final Environmental Assessment for Establishment of a New C-130 Landing Zone for 58 SOW

    Science.gov (United States)

    2013-10-01

    sand about 10 inches thick. The subsoil is brown light sandy clay loam about 12 inches thick. The substratum is pink loam and sandy loam that has a...Madurez series soils is light brown loamy fine sand approximately 10 inches thick, with a brown light sandy clay loam subsoil about 12 inches thick...Closure Opening/Comments Count Sanitary Can w/folded seam 3” dia. x 4” ht. 1 Potted meat cans w/solder 2” dia. x 1 5/8” ht. ”Est-20-A” on base 2

  2. Effect of organic amendments on nitrate leaching mitigation in a sandy loam soil of Shkodra district, Albania

    Directory of Open Access Journals (Sweden)

    Erdona Demiraj

    2018-03-01

    Full Text Available European lacustrine systems are frequently exposed to nitrate (NO3– pollution causing eutrophication processes. An example of these lakes is Shkodra Lake, a large, shallow lake shared by Albania and Montenegro, in the Balkans Peninsula. Shkodra Lake is a natural sink that collects NO3– from agricultural activities, widely diffused in the surrounding area. The additions of wheat straw and biochar have been suggested to increase soil NO3– retention of agricultural lands. To better understand the role of these two organic soil amendments in mitigating NO3– leaching from arable lands, a pot experiment using a representative sandy loam soil of the Skodra Lake basin was performed. More specifically, a greenhouse experiment with Lolium multiflorum L. and Zea mays L., was carried out for three months, to evaluate the concentrations of NO3–-N in leachate and the cumulative leaching losses of NO3–-N, after wheat straw (10 Mg ha–1 and biochar (10 Mg ha–1 soil addition, under the same rate of NPK fertiliser (300 kg ha–1. The effect of the two organic amendments on nitrate retention, was evaluated according to two methods: i Soil NO3–-N leaching with distilled water; and ii Soil NO3–-N extraction with 2M KCl. The leached NO3–-N and the Potentially Leachable NO3–-N (2M KCl extraction were respectively determined. N uptake by plants, as well as the Nitrogen Use Efficiency were also calculated. A retention effect on nitrate was found in Lolium multiflorum L. and wheat straw treatments compared to control, by reducing leached NO3–-N almost to 35%. In SBFL (soil+biochar+fertiliser+Lolium treatment, biochar effectively reduced the total amount of nitrate in leachate of 27% and 26% compared to SFL (soil+fertiliser+Lolium and SSFL (soil+straw+fertiliser+Lolium treatments, respectively. The potentially leachable NO3–-N was two to four times higher than the leached NO3–-N. The amount of potentially leachable NO3–-N per hectare ranged

  3. Isotopic study (Sr-Nd) of the origin of Holocene fine-grained deposits on the Atlantic littoral, SW France

    International Nuclear Information System (INIS)

    Parra, M.; Jouanneau, J.M.; Grousset, F.; Latouche, C.; Castaing, P.; Trouky, H.

    1998-01-01

    The fine-grained sediments of the West Gironde mud patch derive mainly from materials supplied via the Gironde estuary. Between 1500 and 1200/1300 years BP and 300/400 years BP and the present day, the Sr isotopic and chemical compositions of the estuarine silty clay inputs are the same. In contrast, these compositions were different during the period 1200/1300 to 300/400 years BP. These variation probably reflect anthropogenic activities including cultivation and agriculture, in the Garonne and Dordogne drainage basins during the medieval period. Modern silty clay sedimentation in the mud flats of the Marennes-Oleron basin and Perthuis Breton is characterised by the occurrence of important quantities (between 40 and 90 % of the total) of detritus that issues from the Gironde estuary. The autochthonous silty clays derived from outcrops of Jurassic green marls and Flandrian deposits are mixed with estuarine autochthonous clays delivered by coastal surface currents. In the Anse de l'Aiguillon, the muds are mainly composed of these autochthonous silty clays. The silty clay infilling of these mud flats has been highly influenced by the development of the oyster and shellfish aquaculture. (authors)

  4. Effects of tillage during the nonwaterlogged period on nitrous oxide and nitric oxide emissions in typical Chinese rice-wheat rotation ecosystems

    Science.gov (United States)

    Yao, Zhisheng; Zhou, Zaixing; Zheng, Xunhua; Xie, Baohua; Liu, Chunyan; Butterbach-Bahl, Klaus; Zhu, Jianguo

    2010-03-01

    Tillage practices result in major changes to soil environmental conditions and to the distribution of crop residues and nutrients in the soil profile, which may consequently affect the biogenic production and emission of N trace gases. To investigate the effects of tillage during the nonwaterlogged period on nitric oxide (NO) and nitrous oxide (N2O) emissions in rice-wheat rotation systems, we performed field experiments at three sites (Suzhou, Wuxi, and Jiangdu) in the Yangtze River Delta using static chamber techniques. The results showed that the effect of tillage on the emissions of both gases differed among the three field sites due to differences in agricultural management and soil texture. At the site with a light soil texture (Jiangdu: sandy loam), no tillage resulted in reduced NO emissions (0.5 kg N ha-1) as compared to conventionally tilled fields (0.9 kg N ha-1; p tillage plots showed significantly higher emissions (p tillage resulted in lower NO and higher N2O emissions from either N fertilized or unfertilized fields even though these results were not statistically significant. In the silty clay loam soils (Suzhou), which showed the highest soil organic carbon contents and the highest rates of N trace gas emissions in all three of the investigated sites, reduced tillage resulted in much higher NO emissions, whereas N2O emissions were not obviously influenced by tillage practices (reduced tillage versus tillage: NO, 9.5 versus 5.4 kg N ha-1; N2O, 10.6 versus 9.0 kg N ha-1). Similar effects of tillage were observed for the direct emission factors of the applied N during the wheat season. The observed emission factors for the different sites ranged from 0.3% to 2.4% for N2O (mean: 1.0%) and from 0.1% to 4.0% (mean: 0.9%) for NO, respectively. The observed site-to-site differences in emission factors are most likely the results of variations in soil properties (such as texture and pH) and agricultural practices (such as tillage and crop residue management

  5. Potential universal applicability of soil bioindicators: evaluation in three temperate ecosystems Aplicación potencial universal de bioindicadores del suelo: su evaluación en tres ecosistemas templados

    Directory of Open Access Journals (Sweden)

    Mirta G González

    2007-12-01

    Full Text Available Three selected soils from three countries with temperate climates have been analyzed. Two of the soils are silty loams (Buenos Aires, Argentina, and Salamanca, Spain and the third one is a sandy loam (Peccioli, Italy. Soil samples representing three agricultural managements were obtained from the top layer (0-10 cm, i.e. intensively cultivated, cultivated and undisturbed native soils. Soil organic carbon (SOC, total nitrogen (Nt, ATP, urease, protease, phosphatase, b-glucosidase, dehydrogenase (DHA, and arginine ammonification (ARA were determined and compared. SOC and Nt were significantly higher (P Se compararon las actividades enzimáticas de distintos ecosistemas con diferentes características de uso de suelo para utilizarlas como bioindicadores. Se analizaron suelos de tres países de climas templados. Dos de los suelos presentan textura franco limosa (Buenos Aires, Argentina y Salamanca, España y el tercero franco arenosa (Peccioli, Italia. Se obtuvieron muestras de 10 cm de profundidad provenientes de tres manejos diferentes en cada uno de ellos: agricultura intensiva, rotación cultivo-pastura y suelo nativo. En todos los sitios se determinaron y compararon el Carbono orgánico(SOC, Nitrógeno total(Nt, contenido de ATP, acividad enzimática de la ureasa, proteasa, fosfatasa, b-glucosidasa, deshidrogenasa (DHA y arginina(ARA. Se encontró una buena correlación (p < 0,05 entre ATP, DHA, ARA con el SOC y Nt, indicando que estos parámetros del suelo están relacionados con las propiedades biológicas y la actividad bioquímica. No se encontró correlación entre DHA con el SOC, con el Nt , ni con la actividad de la proteasa en suelos de agricultura intensiva, indicando que en ecosistemas de bajos contenidos de sustratos exógenos para metabolizar, los microorganismos están en un nivel bajo de actividad. La similitud de los resultados obtenidos de los suelos de tres diferentes países confirman la utilidad de las variables bioqu

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

    Science.gov (United States)

    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

  7. Peanut plant growth and yield as influenced by co-inoculation with Bradyrhizobium and some rhizo-microorganisms under sandy loam soil conditions

    Directory of Open Access Journals (Sweden)

    F.Sh.F. Badawi

    2011-06-01

    Full Text Available The ability of tested rhizomicrobial isolates (Serratia marcescens and Trichoderma harzianum along with a strain of root nodule bacteria (Bradyrhizobium spp. to exhibit some PGP-properties was evaluated in vitro conditions. The main PGP-properties, namely the ability to solubilize-P and production of IAA, as well as production of siderophores and HCN were examined. Additionally, field trials were conducted on sandy loam soil at El-Tahrir Province during two successive summer seasons to study the effect of co-inoculation with Bradyrhizobium either individually or together with S. marcescens and/or T. harzianum on nodulation, some plant growth characters, peanut yield and its yield components. The in vitro experiment revealed that all of the tested microorganisms were apparently able to trigger PGP-properties. Phosphate solubilization was the common feature of the employed microorganisms. However, T. harzianum appeared to be superior to other microorganisms, and Bradyrhizobium displayed the lowest capacity. The ability of the microorganisms to produce indole compounds showed that S. marcescens was more effective in IAA production and followed by Bradyrhizobium. Capacity of S. marcescens and T. harzianum to excrete ferric-specific ligands (siderophores and HCN was detected, while Bradyrhizobium failed to produce such compounds. Results of field trials showed that the uninoculated peanut had the least nodulation status, N2-ase activity and all vegetative growth characters in both studied seasons. Bacterization of peanut seeds with bradyrhizobia exerted considerable improvement in number and mass of root nodules, increased the rate of acetylene reduction and all growth characters in comparison to the uninoculated control. The synergy inoculation between bradyrhizobia and any of the tested microorganisms led to further increases of all mentioned characters and strengthened the stimulating effect of the bacterial inoculation. However, the promotive

  8. Estimating the saturated soil hydraulic conductivity by the near steady-state phase of a beerkan infiltration run

    Science.gov (United States)

    Di Prima, Simone; Bagarello, Vincenzo; Iovino, Massimo

    2017-04-01

    soils (sand, S; loamy sand, LS; sandy loam, SAL; loam, L; silt loam, SIL and silty clay loam, SCL) from UNSODA database and different initial water contents. Comparison with other existing procedures were also carried out. The SSBI method allowed accurate estimation of saturated soil hydraulic conductivity of both field and analytically generated data. For analytically generated data, the most accurate predictions were obtained with the method 2 by Wu et al. (1999) for the S and LS soils (prediction errors not exceeding 3.8%) and with the SSBI method for the other four soils (error Taha, A., Ross, P., Angulo-Jaramillo, R., 1996. Hydrological and thermal behaviour of the vadose zone in the area of Barrax and Tomelloso (Spain): Experimental study, analysis and modeling. Project UE n. EV5C-CT 92, 00-90. Lassabatere, L., Angulo-Jaramillo, R., Soria Ugalde, J.M., Cuenca, R., Braud, I., Haverkamp, R., 2006. Beerkan Estimation of Soil Transfer Parameters through Infiltration Experiments—BEST. Soil Science Society of America Journal 70, 521. doi:10.2136/sssaj2005.0026 Reynolds, W.D., Elrick, D.E., 1990. Ponded Infiltration From a Single Ring: I. Analysis of Steady Flow. Soil Science Society of America Journal 54, 1233. doi:10.2136/sssaj1990.03615995005400050006x Wu, L., Pan, L., Mitchell, J., Sanden, B., 1999. Measuring Saturated Hydraulic Conductivity using a Generalized Solution for Single-Ring Infiltrometers. Soil Science Society of America Journal 63, 788. doi:10.2136/sssaj1999.634788x Yilmaz, D., Lassabatere, L., Angulo-Jaramillo, R., Deneele, D., Legret, M., 2010. Hydrodynamic Characterization of Basic Oxygen Furnace Slag through an Adapted BEST Method. Vadose Zone Journal 9, 107. doi:10.2136/vzj2009.0039

  9. Passive Microwave Observation of Soil Water Infiltration

    Science.gov (United States)

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

    1997-01-01

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

  10. INFLUENCE OF VERMICOMPOST ON THE PHYSICO-CHEMICAL AND BIOLOGICAL PROPERTIES IN DIFFERENT TYPES OF SOIL ALONG WITH YIELD AND QUALITY OF THE PULSE CROP-BLACKGRAM

    Directory of Open Access Journals (Sweden)

    K. Parthasarathi, M. Balamurugan, L. S. Ranganathan

    2008-01-01

    Full Text Available Field experiments were conducted during 2002-2003 on clay loam, sandy loam and red loam soil at Sivapuri, Chidambaram, Tamil Nadu, to evaluate the efficacy of vermicompost on the physico-chemical and biological characteristics of the soils and on the yield and nutrient content of blackgram - Vigna mungo, in comparison to inorganic fertilizers nitrogen, phosphorous, potassium. Vermicompost had increased the pore space, reduced particle and bulk density, increased water holding capacity, cation exchange capacity, reduced pH and electrical conductivity, increased organic carbon content, available nitrogen, phosphorous, potassium and microbial population and activity in all the soil types, particularly clay loam. The yield and quality (protein and sugar content in seed of blackgram was enhanced in soils, particularly clay loam soil. On the contrary, the application of inorganic fertilizers has resulted in reduced porosity, compaction of soil, reduced carbon and reduced microbial activity.

  11. Environmental Assessment, United States Air Force Proposed Lease Replacement for Scandia Elementary School, Travis Air Force Base, California

    Science.gov (United States)

    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

  12. Soil of the lower valley of the Dragonja river (Slovenia

    Directory of Open Access Journals (Sweden)

    Tomaž PRUS

    2015-11-01

    Full Text Available Soil of the lower valley of the river Dragonja developed under specific soil-forming factors. Soil development in the area was influenced by alluvial sediments originating from surrounding hills, mostly of flysch sequence rocks, as a parent material, Sub-Mediterranean climate and the vicinity of the sea. Different soil classification units (Gleysol and Fluvisol were proposed for that soil in previous researches. The aim of our study was the evaluation of morphological, chemical and mineralogical characteristics of soil, based on detailed soil description and analyses, and to define the appropriate soil classification units. Field examinations revealed that the soil had a stable blocky or subangular structure and did not express substantial hydromorphic forms. Soil pH value was ranging from 6.9 to 7.5. In most locations electroconductivity (ECe did not exceed 2 ds/m. Base saturation was high (up to 99 %, with a majority of Ca2+ ions. Exchangeable sodium percentage (ESP was ranging from 0.2 to 3.8 %, which is higher compared to other Slovenian soils but does not pose a risk to soil structure. Soil has silty clay loam texture with up to 66 % of silt. Prevailing minerals were quartz, calcite and muscovite/illite. No presence of swelling clay mineral montmorillonite was detected. According to Slovenian soil classification, we classified the examined soil as alluvial soil. According to WRB soil classification, the soil was classified as Cambisol.

  13. Effect of adding phosphogypsum to the soil on the growth, yields, radionuclides, trace elements and fluorine accumulation in some crops

    International Nuclear Information System (INIS)

    Al-Oudat, M.; Sharabi, N. E.; Kanacri, S.

    2001-12-01

    large quantities of phosphogypsum, a by-product of phosphate fertilizer industry, are stacked close to urban areas in Syria. This may pose negative impacts on the environment. Many studies have reported positive effects of phosphogypsum application on nutrient levels, physical and chemical properties of agricultural soils. There are some concerns that the application of phosphogypsum to agricultural lands may result in the uptake by plant of radionuclides, fluorine and trace elements. Phosphogypsum, which has a radioactivity of 430 Bq/Kg, was mixed with silty loam soil, at different rates (0, 10, 20, 40 and 80 t/ha), the experiments were carried out using chick pea, maize cotton and spinach. The results showed that adding phosphogypsum to the soil, at a rate ranging between 10 and 40 t/ha, increased the infiltration rate, electrical conductivity and concentration of available S, Mg, Ca, P. It also increased significantly the yields of studied crops. The radioactivities in the shoot systems and grains yields of crops grown on these soil-phosphogypsum mixtures were below detection level. In addition, phosphogypsum application did not cause accumulation of trace elements in soil or plants. The fluorine concentrations in plants increased but remained less than the allowable level (30 ppm). Therefor, adding phosphogypsum to agricultural soils (at a rate of 10-20 t/ha) can be considered an-effective way of improving soil properties, crop productivity and represents a way of phosphogypsum utilization which reduces its negative effects on the environment. (authors)

  14. Degradation kinetics and safety evaluation of buprofezin residues in grape (Vitis vinifera L.) and three different soils of India.

    Science.gov (United States)

    Oulkar, Dasharath P; Banerjee, Kaushik; Patil, Sangram H; Upadhyay, Ajay K; Taware, Praveen B; Deshmukh, Madhukar B; Adsule, Pandurang G

    2009-02-01

    This work was undertaken to determine the preharvest interval (PHI) of buprofezin to minimize its residues in grapes and thereby ensure consumer safety and avoid possible non-compliance in terms of residue violations in export markets. Furthermore, the residue dynamics in three grapevine soils of India was explored to assess its environmental safety. Residues dissipated following non-linear two-compartment first + first-order kinetics. In grapes, the PHI was 31 days at both treatments (312.5 and 625 g a.i. ha(-1)), with the residues below the maximum permissible intake even 1 h after foliar spraying. Random sampling of 5 kg comprising small bunchlets (8-10 berries) collected from a 1 ha area gave satisfactory homogeneity and representation of the population. A survey on the samples harvested after the PHI from supervised vineyards that received treatment at the recommended dose showed residues below the maximum residue limit (MRL) of 0.02 mg kg(-1) applicable for the European Union. In soil, the degradation rate was fastest in clay soil, followed by sandy loam and silty clay, with a half-life within 16 days in all the soils. The recommendation of the PHI proved to be effective in minimizing buprofezin residues in grapes. Thus, this work is of high practical significance to the domestic and export grape industry of India to ensure safety compliance in respect of buprofezin residues, keeping in view the requirements of international trade.

  15. Napropamide residues in runoff and infiltration water from pepper production.

    Science.gov (United States)

    Antonious, George F; Patterson, Matthew A

    2005-01-01

    A field study was conducted on a Lowell silty loam soil of 2.7% organic matter at the Kentucky State University Research Farm, Franklin County, Kentucky. Eighteen universal soil loss equation (USLE) standard plots (22 x 3.7 m each) were established on a 10% slope. Three soil management practices were used: (i) class-A biosolids (sewage sludge), (ii) yard waste compost, each mixed with native soil at a rate of 50 ton acre(-1) on a dry-weight basis, and (iii) a no-mulch (NM) treatment (rototilled bare soil), used for comparison purposes. Devrinol 50-DF "napropamide" [N,N-diethyl-2-(1-naphthyloxy) propionamide] was applied as a preemergent herbicide, incorporated into the soil surface, and the plots were planted with 60-day-old sweet bell pepper seedlings. Napropamide residues one hour following spraying averaged 0.8, 0.4, and 0.3 microg g(-1) dry soil in sewage sludge, yard waste compost, and no-mulch treatments, respectively. Surface runoff water, runoff sediment, and napropamide residues in runoff were significantly reduced by the compost and biosolid treatments. Yard waste compost treatments increased water infiltration and napropamide residues in the vadose zone compared to sewage sludge and NM treatments. Total pepper yields from yard waste compost amended soils (9187 lbs acre(-1)) was significantly higher (P soil amended with class-A biosolids (6984 lbs acre(-1)) or the no-mulch soil (7162 lbs acre(-1)).

  16. Reuse of liquid, dewatered, and composted sewage sludge on agricultural land: effects of long-term application on soil and crop.

    Science.gov (United States)

    Mantovi, Paolo; Baldoni, Guido; Toderi, Giovanni

    2005-01-01

    To evaluate the effects of repeated sewage sludge applications in comparison to mineral fertilisers on a winter wheat-maize-sugar beet rotation, a field experiment on a silty-loam soil, in the eastern Po Valley (Italy), was carried out since 1988. Municipal-industrial wastewater sludge as anaerobically digested, belt filtered (dewatered), and composted with wheat straw, has been applied at 5 and 10 Mg DM ha(-1)yr(-1). Biosolids gave crop yields similar to the highest mineral fertiliser dressing. However, with the higher rate of liquid and dewatered sludge, excessive N supply was harmful, leading to wheat lodging and poor quality of sugar beet and wheat crops. From this standpoint compost use was safer. Biosolids increased organic matter (OM), total N, and available P in the soil and reduced soil alkalinity, with more evident effects at the highest rate. Compost caused the most pronounced OM top soil accumulation. Significant accumulations of total Zn and Cu were detected in amended top soil, but no other heavy metals (Cd, Cr, Ni, Pb), whose total concentration remained well below the hazard limits. Biosolid applications significantly increased the content of N, P, Zn, and Cu in wheat grain, N and Cu in sugar beet roots, and only Cu in maize grain. The application of biosolids brought about notable benefits to soil fertility but it was associated with possible negative effects on water quality due to increased P availability and on soil ecology due to Zn accumulation.

  17. Potassium-phosphorus relationships in cotton (gossypium hirsutum L.) as affected by potassium nutrition

    International Nuclear Information System (INIS)

    Makhdum, M.I.; Ashraf, M.

    2007-01-01

    Field studies were undertaken to determine the interrelationship between potassium (K+) concentration in various organs of plant and phosphorus (P) content as influenced by K-nutrition in cotton. The experiment was conducted on Miani soil series silt loam and classified as Calcaric Cambisols, fine silty, mixed Hyperthermic Fluventic Haplocambids. The treatments consisted .of (a) four cotton (Gossypium hirsutum L.) cultivars (CI.M-448, CIM-IIOO, Karishma, S-12); and (b) four potassium fertilizer doses (0, 62.5, 125.0, 250.0 kg K ha-l). The design of experiment was split plot (main: cultivars, sub-plot: K-doses). The plant samples were collected at five stages of growth, i.e., first flower bud., first flower, peak flowering, first boll split and maturity. The various parts of plants were analyzed for phosphorus and potassium concentration at various stages of growth. Phosphorus concentration in leaves, stems, burs, seed and lint decreased with concurrent increase in K-doses. Crop maintained 0.22% phosphorus concentration in leaf tissues at first flower bud and dropped to 0.11% at maturity. Cultivars differed greatly amongst themselves in terms of maintaining P content in their different parts. Averaged across K-doses, cv. CIM-448 maintained the highest P content in all parts than other cultivars. There was a negative and significant correlation co-efficient between K and P concentration in various parts of the plant. The study demonstrated antagonistic interaction between K+ and P in cotton plant under irrigated conditions. (author)

  18. Effect of Incident Rainfall Redistribution by Maize Canopy on Soil Moisture at the Crop Row Scale

    Directory of Open Access Journals (Sweden)

    Marco Martello

    2015-05-01

    Full Text Available The optimization of irrigation use in agriculture is a key challenge to increase farm profitability and reduce its ecological footprint. To this context, an understanding of more efficient irrigation systems includes the assessment of water redistribution at the microscale. This study aimed to investigate rainfall interception by maize canopy and to model the soil water dynamics at row scale as a result of rain and sprinkler irrigation with HYDRUS 2D/3D. On average, 78% of rainfall below the maize canopy was intercepted by the leaves and transferred along the stem (stemflow, while only 22% reached the ground directly (throughfall. In addition, redistribution of the water with respect to the amount (both rain and irrigation showed that the stemflow/throughfall ratio decreased logarithmically at increasing values of incident rainfall, suggesting the plant capacity to confine the water close to the roots and diminish water stress conditions. This was also underlined by higher soil moisture values observed in the row than in the inter-row at decreasing rainfall events. Modelled data highlighted different behavior in terms of soil water dynamics between simulated irrigation water distributions, although they did not show significant changes in terms of crop water use efficiency. These results were most likely affected by the soil type (silty-loam where the experiment was conducted, as it had unfavorable physical conditions for the rapid vertical water movement that would have increased infiltration and drainage.

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

    International Nuclear Information System (INIS)

    Torre Jorgenson, M; Harden, Jennifer; Manies, Kristen; Kanevskiy, Mikhail; Shur, Yuri; O’Donnell, Jonathan; Wickland, Kim; Striegl, Robert; Ewing, Stephanie; Zhuang Qianlai; Koch, Josh

    2013-01-01

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

  20. Bioremediating silty soil contaminated by phenanthrene, pyrene ...

    African Journals Online (AJOL)

    sunny t

    benzo(a)pyrene using Bacillus sp. and Pseudomonas sp.: Biosurfactant/Beta vulgaris ... potential human mutagens and carcinogens (Grimmer,. 1983). Chemical and ...... of naphthalene on zeolite from aqueous solution. J. Colloid Interf. Sci.

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

    Science.gov (United States)

    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. The increase in the organic carbon content upon amendment and the natural clay content of the soils are revealed to be responsible for the higher adsorption of Diuron when compared with Terbuthylazine, Clomazone and MCPA. Desorption of the herbicides was highly inhibited in the soils treated with mucilage; only Terbuthylazine showed a slight desorption in the case of loam and clay loam-soils. This study leads to the conclusion that mucilage from Chia seeds used as soil conditioner can reduce the mobility of herbicides tested in agricultural soils with different physico-chemical properties. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. [Characteristics of N2, N2O, NO, CO2 and CH4 Emissions in Anaerobic Condition from Sandy Loam Paddy Soil].

    Science.gov (United States)

    Cao, Na; Wang, Rui; Liao, Ting-ting; Chen, Nuo; Zheng, Xun-hua; Yao, Zhi-sheng; Zhang, Hai; Butterbach-Bahl, Klaus

    2015-09-01

    Understanding the characteristics of the production of nitrogen gases (N2, N2O and NO), CO2 and CH4 in anaerobic paddy soils is not only a prerequisite for an improved mechanistic understanding of key microbial processes involved in the production of atmospheric greenhouse gases (GHG), but might also provide the basis for designing greenhouse gas mitigation strategies. Moreover, quantifying the composition fractions of denitrification gaseous products is of key importance for improving parameterization schemes of microbial processes in process-oriented models which are increasingly used for assessing soil GHG emissions at site and national scales. In our experiments we investigated two sandy loam soils from two paddy fields. The initial concentrations of soil nitrate and dissolved organic carbon (DOC) were set at approximately 50 mg.kg-1 and mg.kg-1, respectively, by adding a mixture solution of KNO3 and glucose. The emissions of N2, N2O NO, CO2 and CH4, as well as concentrations of carbon and nitrogen substrates for each soil sample were measured simultaneously, using a gas-flow-soil-core technique and a paralleling substrate monitoring system. The results showed that the accumulative emissions of N2, N2O and NO of the two soil samples for the entire incubation period were 6 - 8, 20, and 15 - 18 mg.kg-1, respectively. By measuring the cumulative emissions of denitrification gases (N, = N2 + N2O + NO) we were able to explain 95% to 98% of observed changes in s1ifr nilrate concentrations. The mass fractions of N2, N2O and NO emissions to Nt were approximately 15% -19%, 47% -49%, and 34% -36%, respectively. Thus, in our experiments N2O and NO were the main products of denitrification for the entire incubation period. However, as the temporal courses of hourly or daily production of the denitrification gases showed, NO production dominated and peaked firstly, and then N2O, before finally N2 became the dominant product. Our results show the high temporal dynamic of

  3. Jatropha curcas L. Root Structure and Growth in Diverse Soils

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2013-01-01

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

  5. Jatropha curcas L. Root Structure and Growth in Diverse Soils

    Directory of Open Access Journals (Sweden)

    Ofelia Andrea Valdés-Rodríguez

    2013-01-01

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

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

    Science.gov (United States)

    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 ...

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

    Science.gov (United States)

    Ahmed, Ahmed S. F.; Raghavan, Vijaya

    2018-01-01

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

  8. KC-46A Formal Training Unit (FTU) and First Main Operating Base (MOB 1) Beddown EIS. Volume 1

    Science.gov (United States)

    2014-03-01

    discharged into the sanitary sewer system. Most of the sanitary sewer system at Altus AFB is over 45 years old and constructed of vitrified clay ...drained (USDA 2002a, 2003). The textures of the Tillman-Hollister soils range from clay loam to clay , with the Hollister subsurface soils being more clayey...range from sandy to sandy loam to sandy clay loam, with the Nobscot soils having a more sandy nature, especially in the surface soils (Altus AFB 2009a

  9. Final KC-46A Formal Training Unit (FTU) and First Main Operating Base (MOB 1) Beddown EIS

    Science.gov (United States)

    2014-03-01

    years old and constructed of vitrified clay pipe or concrete. Of the sanitary sewer lines field surveyed in 2004 and 2007, approximately 85 percent...Hollister soils are very deep and well-drained (USDA 2002a, 2003). The textures of the Tillman-Hollister soils range from clay loam to clay , with...The textures of the Miles-Nobscot soils range from sandy to sandy loam to sandy clay loam, with the Nobscot soils having a more sandy nature

  10. 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)

    Science.gov (United States)

    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.

  11. Characteristics of soils developed from alluvium and their potential for cocoa plant development in East Kolaka Regency, Southeast Sulawesi

    Directory of Open Access Journals (Sweden)

    E. Yatno

    2016-04-01

    Full Text Available Cocoa is one of plantation commodities that is quite important for the national economy. Land management for the development of this plant should pay attention to the characteristics of the soil. Three soil profiles formed from alluvium parent material in East Kolaka Regency were investigated to determine the mineralogical, physical, and chemical soil properties, as well as the potential of the land for the development of cocoa plant. The results showed that the mineral composition of the sand fraction was dominated by quartz, while the clay mineral fraction was composed of kaolinite, hydrate halloysite, interstratified of illite-vermiculite and smectite. The soils were characterized by poor drainage, low bulk density (0.78 to 0.95 g / cm3, moderate available water pores (10-15%, slow to fast permeability (0.10 to 14.05 cm / h, silty clay loam to silty clay texture of top soil, acidic soil reaction (pH 4.62 to 5.47, high organic C content (3.86 to 4.60% in the top soil and very low organic C content (<0.65% in the lower layer, moderate to high available P (14-38 mg / kg in the A horizon and very low to moderate (1-18 mg / kg in horizon B, moderate to high P2O5 (30-71 mg / 100g in horizon A and extremely low (1-11 mg / 100g in horizon B, very low to moderate K2O (3-28 mg / 100g , moderate to high exchangeable Ca (9.32 to 13.92 cmolc / kg in the upper and lower (0.70 to 5.04 cmolc / kg in the bottom layer, high exchangeable Mg content (2.83 to 8.95 cmolc / kg, high soil CEC (34.18 to 38.28 cmolc / kg in the upper layer and low to moderate (7.87 to 20.39 cmolc / kg in the bottom layer, moderate to high base saturation (44-68%, and very low to moderate Al saturation (0-17%. At the family level, the soil was classified as Fluvaquentic Endoaquepts (EK 1 profile and Typic Endoaquepts (EK 2 and EK 3 profiles, finely loamy, mix, acid, isohypertermik. The land was marginally suitable (S3 for cocoa plant with the contraints of impeded drainage, acid soil

  12. Pupation Behaviors and Emergence Successes of Ectropis grisescens (Lepidoptera: Geometridae) in Response to Different Substrate Types and Moisture Contents.

    Science.gov (United States)

    Wang, Huifang; Ma, Tao; Xiao, Qiang; Cao, Panrong; Chen, Xuan; Wen, Yuzhen; Xiong, Hongpeng; Qin, Wenquan; Liang, Shiping; Jian, Shengzhe; Li, Yanjun; Sun, Zhaohui; Wen, Xiujun; Wang, Cai

    2017-12-08

    Ectropis grisescens Warren (Lepidoptera: Geometridae) is one of the most severe pests of tea plants in China. This species commonly pupates in soil; however, little is known about its pupation ecology. In the present study, choice and no-choice tests were conducted to investigate the pupation behaviors and emergence success of E. grisescens in response to different substrates (sand, sandy loam 1, sandy loam 2, and silt loam) and moisture contents (5, 20, 35, 50, 65, and 80%). Moisture-choice bioassays showed that significantly more E. grisescens individuals pupated in or on soil (sandy loam 1 and 2 and silt loam) that was at the intermediate moisture levels, whereas 5%- and 35%-moisture sand was significantly more preferred over 80%-moisture sand for pupating. Substrate-choice bioassays showed that sand was most preferred by E. grisescens individuals at 20%- and 80%-moisture levels, but no preference was detected among the four substrates at 50%-moisture content. No-choice tests showed that the percentage of burrowed E. grisescens individuals and pupation depth were significantly lower when soil was dry (20% moisture) or wet (80% moisture). In addition, 20%-moisture sandy loam 2 and silt loam significantly decreased the body water content of pupae and emergence success of adults compared to 50%-moisture content. However, each measurement (percentage of burrowed individuals, pupation depth, body water content, or emergence success) was similar when compared among different moisture levels of sand. Interestingly, pupae buried with 80%-moisture soil exhibited significantly lower emergence success than that were unburied. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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

    Science.gov (United States)

    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

  14. Biochar Effect on Maize Yield and Soil Characteristics in Five Conservation Farming Sites in Zambia

    Directory of Open Access Journals (Sweden)

    Alfred Obia

    2013-04-01

    Full Text Available 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

  15. influence of some types of Algerian soil on the development of rot-knot nematodes Meloidogyne incognita, M. javanica and M. arenaria (Tylenchida,Meloidogynidae)

    International Nuclear Information System (INIS)

    Hammach, M.

    2010-01-01

    Crops under greenhouses offer the possibility of vegetables production of high added value by focusing on earliness. They help to spread the availability timing of vegetables and fruits in the market throughout the year. However, these crops are subject to numerous attacks entailing heavy losses of yield quantity and quality. The plant parasitic nematodes especially rot-knot nematodes of the genus Meloidogyne are considered dangerous enemies of these cultures. The evolution study of these nematodes in different soil types allows one to compare the migration and movement of these nematodes in sandy soils considered as light soils, in clay soils heavy and intermediate silty clay soils. These soils have also rates of organic matter and a percentage of magnesium and calcium that might provide better conditions to the survival and migration of second stage larvae inoculated at a rate of 650 juveniles per pot of 24 cm in diameter where plants of melon Cucumis melo var. (Charentais) known to be susceptible to Meloidogyne was cultivated. The results for the population development of Meloidogyne, after a growing period of 3 months show an increase in the number of eggs, juvenile stages, inflated, swollen females and males in the 3 types of soil and that independently of clay fraction although clay soil may asphyxiate Meloidogyne. The development of the three species of Meloidogyne studied in these soils, the parameters taken into consideration (index of galls, which were 1.58, 1.75 and 1.5 for the sandy clay and the middle ground soils, vigour index and the evolution of populations of Meloidogyne and roots and soil as well as parameters related to production reveal the adaptation of these root-knot nematodes to the clay and sandy loam soils. At the end of culture, the final populations are important in the soils studied; 2680 for soil S. (sandy), 2272 for soil A (clay) and 2327 for soil I (intermediate) with a multiplication rate almost similar ( 4.12, 3.49 and 3

  16. Biological treatment of soils contaminated with hydrophobic organics using slurry- and solid-phase techniques

    Science.gov (United States)

    Cassidy, Daniel H.; Irvine, Robert L.

    1995-10-01

    Both slurry-phase and solid-phase bioremediation are effective ex situ soil decontamination methods. Slurrying is energy intensive relative to solid-phase treatment, but provides homogenization and uniform nutrient distribution. Limited contaminant bioavailability at concentrations above the required cleanup level reduces biodegradation rates and renders solid phase bioremediation more cost effective than complete treatment in a bio-slurry reactor. Slurrying followed by solid-phase bioremediation combines the advantages and minimizes the weaknesses of each treatment method when used alone. A biological treatment system consisting of slurrying followed by aeration in solid phase bioreactors was developed and tested in the laboratory using a silty clay loam contaminated with diesel fuel. The first set of experiments was designed to determine the impact of the water content and mixing time during slurrying on the rate an extent of contaminant removal in continuously aerated solid phase bioreactors. The second set of experiments compared the volatile and total diesel fuel removal in solid phase bioreactors using periodic and continuous aeration strategies. Results showed that slurrying for 1.5 hours at a water content less than saturation markedly increased the rate and extent of contaminant biodegradation in the solid phase bioreactors compared with soil having no slurry pretreatment. Slurrying the soil at or above its saturation moisture content resulted in lengthy dewatering times which prohibited aeration, thereby delaying the onset of biological treatment in the solid phase bioreactors. Results also showed that properly operated periodic aeration can provide less volatile contaminant removal and a grater fraction of biological contaminant removal than continuous aeration.

  17. Effluent Storage and Biomat Occurrence among Septic System Absorption Field Architectures in a Typic Fragiudult.

    Science.gov (United States)

    Prater, N J M; Brye, K R; Dunn, S; Soerens, T S; Sharpley, A N; Mason, E; Gbur, E E

    2013-07-01

    On-site wastewater treatment systems (OWTSs) are commonly used by households in areas of low population density to treat household wastewater and recycle it back to the environment. However, new absorption field products of differing architecture types have recently become available. A 3-yr field study was conducted in Bethel Heights, northwest Arkansas to assess several newer architecture types (i.e., chambers, polystyrene-aggregate, and gravel-less pipe) relative to the traditional pipe-and-gravel design under wet- and dry-soil conditions. Thirteen products of four different architecture types were installed in 46-cm-deep trenches in a Captina silt loam (fine-silty, siliceous, active, mesic Typic Fragiudult). Products were evaluated based on in-trench solution storage measured with an electronic water-level sensor approximately weekly from January 2009 through January 2012. Between May 2010 and January 2012, the thickness of any biomat formation was measured approximately weekly by insertion of a wooden dowel through in-trench monitoring ports. Architecture type alone did not affect ( > 0.05) in-trench solution storage. However, solution storage among individual products differed under wet- and dry-soil conditions ( storage but that several alternative products also had greater solution storage than that of the traditional pipe-and-gravel system. With no observed effluent surfacing, the soil morphology approach appears to be adequate and appropriately environmentally conservative for assigning typical single-family loading rates to alternative OWTS products and to the traditional pipe-and-gravel system. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  18. Mineralization of soil organic matter in biochar amended agricultural landscape

    Science.gov (United States)

    Chintala, R.; Clay, D. E.; Schumacher, T. E.; Kumar, S.; Malo, D. D.

    2015-12-01

    Pyrogenic biochar materials have been identified as a promising soil amendment to enhance climate resilience, increase soil carbon recalcitrance and achieve sustainable crop production. A three year field study was initiated in 2013 to study the impact of biochar on soil carbon and nitrogen storage on an eroded Maddock soil series - Sandy, Mixed, Frigid Entic Hapludolls) and deposition Brookings clay loam (Fine-Silty, Mixed, Superactive, Frigid Pachic Hapludolls) landscape positions. Three biochars produced from corn stover (Zea mays L.), Ponderosa pine (Pinus ponderosa Lawson and C. Lawson) wood residue, and switchgrass (Panicum virgatum L.) were incorporated at 9.75 Mg ha-1 rate (≈7.5 cm soil depth and 1.3 g/cm3 soil bulk density) with a rototiller. The changes in chemical fractionation of soil carbon (soluble C, acid hydrolyzable C, total C, and δ13 C) and nitrogen (soluble N, acid hydrolyzable N, total N, and δ14 N) were monitored for two soil depths (0-7.5 and 7.5 - 15 cm). Soluble and acid hydrolyzable fractions of soil C and N were influenced by soil series and were not significantly affected by incorporation of biochars. Based on soil and plant samples to be collected in the fall of 2015, C and N budgets are being developed using isotopic and non-isotopic techniques. Laboratory studies showed that the mean residence time for biochars used in this study ranged from 400 to 666 years. Laboratory and field studies will be compared in the presentation.

  19. Raw or incubated olive-mill wastes and its biotransformed products as agricultural soil amendments-effect on sorption-desorption of triazine herbicides.

    Science.gov (United States)

    Delgado-Moreno, Laura; Almendros, Gonzalo; Peña, Aránzazu

    2007-02-07

    Raw olive-mill waste and soil amendments obtained from their traditional composting or vermicomposting were added, at rates equivalent to 200 Mg ha-1, to a calcareous silty clay loam soil in a laboratory test, in order to improve its fertility and physicochemical characteristics. In particular, the effects on the sorption-desorption processes of four triazine herbicides have been examined. We found that comparatively hydrophobic herbicides terbuthylazine and prometryn increased their retention on amended soil whereas the more polar herbicides simazine and cyanazine were less affected. Soil application of olive cake, without transformation, resulted in the highest herbicide retention. Its relatively high content in aliphatic fractions and lipids could explain the increased herbicide retention through hydrophobic bonding and herbicide diffusion favored by poorly condensed macromolecular structures. On the other hand, the condensed aromatic structure of the compost and vermicompost from olive cake could hinder diffusion processes, resulting in lower herbicide sorption. In fact, the progressive humification in soil of olive-mill solid waste led to a decrease of sorption capacity, which suggested important changes in organic matter quality and interactions during the mineralization process. When soil amended with vermicompost was incubated for different periods of time, the enhanced herbicide sorption capacity persisted for 2 months. Pesticide desorption was reduced by the addition of fresh amendments but was enhanced during the transformation process of amendments in soil. Our results indicate the potential of soil amendments based on olive-mill wastes in the controlled, selective release of triazine herbicides, which varies depending on the maturity achieved by their biological transformation.

  20. Inoculation of arbuscular mycorrhizal fungi and phosphate solubilizing bacteria in the presence of rock phosphate improves phosphorus uptake and growth of maize

    International Nuclear Information System (INIS)

    Wahid, F.; Sharif, M.; Khan, M. A.; Khan, S. A.

    2016-01-01

    The beneficial microbes like arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing bacteria (PSB) are known to play an important role in phosphorous (P) supply to plants in a sustainable manner in P deficient soils. In this scenario, a pot experiment was conducted under greenhouse condition to assess the synergistic effect of AMF and PSB strains (Coccus DIM7 Streptococcus PIM6 and Bacillus sp. PIS7) on P solubility from RP and their successive uptake by maize (Zea-mays L. Azam) crop at alkaline soil. The experiment was completely randomized design with three replications having calcareous silty clay loam soil, low in organic matter, nitrogen and phosphorus contents. RP was used as a crude phosphate alone and/or in combination with the native AMF and PSB inoculum. The Results indicated that the rhizosphere interactions between AMF and PSB significantly promote RP mineralization in soil and improved all growth parameters including shoot (56 percent), root yield (52 percent), height (41 percent), N (80 percent) and P (91 percent) uptake by the maize plants as compared to control and single inoculation. A remarkable increase in soil spore density, PSB population and percent root colonization in maize plants were also recorded by the combined inoculation of AMF and PSB with RP. From this study, it is concluded that the combined application of AMF and PSB with RP has the potential to improve maize growth and nutrients uptake. Moreover, AMF and PSB inoculants are recommended as useful biofertilizers for enhancing P solubility and bioavailability in P deficient agricultural soils. (author)

  1. soil failure crescent radii measurement for draft in tillage study

    African Journals Online (AJOL)

    user

    1986-09-01

    Sep 1, 1986 ... SCHOOL OF ENGINEERING AND ENGINEERING TECHNOLOGY. FEDERAL UNIVERSITY OF TECHNOLOGY. OWERRI. ABSTRACT. Field clay loam and sandy loam soils were tilled with a chisel .... modified earth moving equation proposed by Mckyes and All was: ... applications of analytical mechanics.

  2. Southeast Florida Sediment Assessment and Needs Determination (SAND) Study

    Science.gov (United States)

    2014-09-01

    sand with some shell beds, sandstone , and limestone *Miami Limestone 0 to 80 ft Oolitic limestone, quartz sand, and sandstone Anastasia 0 to 100 ft...Sand, shell beds, marl, calcareous sandstone (coquina/calcarenite) Fort Thompson 0 to 80 ft Silty limestone, silty sand, clayey marl, shell marl...highly- to moderately- weathered quartzose sandstone , and highly-weathered (saprolitic) to moderately-weathered hard limestone. North-south and

  3. Transformation of the herbicide [14C]glufosinate in soils

    International Nuclear Information System (INIS)

    Smith, A.E.

    1989-01-01

    The degradation of 2 μg/g [ 14 C]glufosinate (DL-homoalan-4-ylmethylphosphinic acid) was studied in clay, clay loam, and sandy loam soils at 85% field capacity and at 20 degree C. Over a 4-week period the soils were extracted and analyzed for transformation products by radiochemical and gas chromatographic techniques. In all soils there was release of [ 14 C]carbon dioxide and formation of [ 14 C]-3-(hydroxymethylphosphinyl)propionic acid (MPPA) as major degradation products. Within 21 days, about 55% of the applied 14 C herbicide had been transformed to MPPA in the sandy loam and 19% to [ 14 C]carbon dioxide. After 28 days, approximately 45% of the 14 C herbicide had been transformed to MPPA in the clay and clay loam and 10% released as [ 14 C]carbon dioxide. At all samplings, other 14 C transformation products appeared to be insignificant

  4. The non-steroidal anti-inflammatory drug diclofenac is readily biodegradable in agricultural soils

    International Nuclear Information System (INIS)

    Al-Rajab, Abdul Jabbar; Sabourin, Lyne; Lapen, David R.; Topp, Edward

    2010-01-01

    Diclofenac, 2-[2-[(2,6-dichlorophenyl)amino]phenyl]acetic acid, is an important non-steroidal anti-inflammatory drug widely used for human and animals to reduce inflammation and pain. Diclofenac could potentially reach agricultural lands through the application of municipal biosolids or wastewater, and in the absence of any environmental fate data, we evaluated its persistence in agricultural soils incubated in the laboratory. 14 C-Diclofenac was rapidly mineralized without a lag when added to soils varying widely in texture (sandy loam, loam, clay loam). Over a range of temperature and moisture conditions extractable 14 C-diclofenac residues decreased with half lives < 5 days. No extractable transformation products were detectable by HPLC. Diclofenac mineralization in the loam soil was abolished by heat sterilization. Addition of biosolids to sterile or non-sterile soil did not accelerate the dissipation of diclofenac. These findings indicate that diclofenac is readily biodegradable in agricultural soils.

  5. Manure biochar influence upon soil properties, phosphorus distribution and phosphatase activities: A microcosm incubation study.

    Science.gov (United States)

    Jin, Yi; Liang, Xinqiang; He, Miaomiao; Liu, Yu; Tian, Guangming; Shi, Jiyan

    2016-01-01

    Using manure-derived-biochar as an alternative phosphorus (P) source has bright future prospects to improve soil P status. A 98-day microcosm incubation experiment was set up for two soils which were amended with manure biochar at proportions of 0, 0.5% and 1.5%. Swine manure samples were air-dried and manure biochar was prepared by pyrolysis at 400 °C for 4 h. As determined by P-31 nuclear magnetic resonance ((31)P NMR) spectroscopy, manure biochar mainly increased the contents and fractions of orthophosphate and pyrophosphate in two soils, while decreased those of monoesters (P<0.05). At the end of incubation, 1.5% of manure biochar raised soil pH by 0.5 and 0.6 units, cation exchange capacity by 16.9% and 32.2%, and soil total P by 82.1% and 81.1% for silt loam and clay loam soils, respectively, as compared with those soils without biochar. Simultaneously, 1.5% of manure biochar decreased acid phosphomonoesterase activities by 18.6% and 34.0% for clay loam and silt loam, respectively; while it increased alkaline phosphomonoesterase activities by 28.5% and 95.1% for clay loam and silt loam, respectively. The enhancement of soil P availability after manure biochar addition was firstly due to the orthophosphate and pyrophosphate as the major P species in manure biochar which directly increased contents of soil inorganic P, and also attributed to the decomposition of some organic P like monoesters by enhanced alkaline phosphomonoesterase activities from manure biochar addition. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Pedological ~cterization, Clay Mine:at~ and .~cation of,

    African Journals Online (AJOL)

    namely, very deep, well drained, dark reddish brown to dark brown, sandy clay loams and sandy clays on the steep convex slopes; very deep, well drained, dark brown to dark red, sandy clay loams and; sandy clays on the linear slopes; and very ...

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

    Science.gov (United States)

    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...

  8. LAMBERSART "LES CONQUERANTS" (DEULE VALLEY, NORTH OF FRANCE) : A WEICHSELIAN EARLY-PLENIGLACIAL SLOPE-BOTTOM VALLEY TRANSITION

    NARCIS (Netherlands)

    Deschodt, Laurent; Munaut, Andre-Valentin; Limondin-Lozouet, Nicole; Boulen, Muriel

    2008-01-01

    The Lambersart "les Conquerants" trench sequence is made of a Shelly loam topped by coarse alluviums. The whole is covered by several meters thick pleniglacial loess. The palynological and malacological data shows that this Shelly loam deposit occured during Early Glacial, in cold and moist

  9. The antihistamine diphenhydramine is extremely persistent in agricultural soil

    International Nuclear Information System (INIS)

    Topp, Edward; Sumarah, Mark W.; Sabourin, Lyne

    2012-01-01

    The widely used antihistamine diphenhydramine is present in municipal biosolids, and is detected in runoff from agricultural land fertilized with biosolids. In the present study the kinetics and major pathways of diphenhydramine dissipation in a loam, sandy loam, and clay loam soil were determined in laboratory incubations. The time to dissipate 50% (DT 50 ) of 14 C-diphenhydramine residues at 30 °C ranged from 88 ± 28 days in the clay loam to 335 ± 145 days in the loam soil. Mineralization of 14 C was insignificant, and diphenhydramine-N-oxide was the only detected extractable transformation product elucidated by radioisotope and HPLC-MS methods. There were no significant effects of municipal biosolids on the kinetics or pathways of removal. Overall, diphenhydramine is quite persistent in soils, and formation of non-extractable soil-bound residues is the major mechanism of diphenhydramine dissipation. -- Highlights: ► Diphenhydramine is a widely used antihistamine drug, is found in biosolids, and in runoff from biosolids-fertilized fields. ► The persistence of 14 C-diphenhydramine was evaluated in soils. ► Half lives ranged from 88 to 335 days. Diphenhydramine-N-oxide was the only detected transformation product. ► Soil-bound residues was a major sink.

  10. The antihistamine diphenhydramine is extremely persistent in agricultural soil

    Energy Technology Data Exchange (ETDEWEB)

    Topp, Edward, E-mail: ed.topp@agr.gc.ca; Sumarah, Mark W.; Sabourin, Lyne

    2012-11-15

    The widely used antihistamine diphenhydramine is present in municipal biosolids, and is detected in runoff from agricultural land fertilized with biosolids. In the present study the kinetics and major pathways of diphenhydramine dissipation in a loam, sandy loam, and clay loam soil were determined in laboratory incubations. The time to dissipate 50% (DT{sub 50}) of {sup 14}C-diphenhydramine residues at 30 Degree-Sign C ranged from 88 {+-} 28 days in the clay loam to 335 {+-} 145 days in the loam soil. Mineralization of {sup 14}C was insignificant, and diphenhydramine-N-oxide was the only detected extractable transformation product elucidated by radioisotope and HPLC-MS methods. There were no significant effects of municipal biosolids on the kinetics or pathways of removal. Overall, diphenhydramine is quite persistent in soils, and formation of non-extractable soil-bound residues is the major mechanism of diphenhydramine dissipation. -- Highlights: Black-Right-Pointing-Pointer Diphenhydramine is a widely used antihistamine drug, is found in biosolids, and in runoff from biosolids-fertilized fields. Black-Right-Pointing-Pointer The persistence of {sup 14}C-diphenhydramine was evaluated in soils. Black-Right-Pointing-Pointer Half lives ranged from 88 to 335 days. Diphenhydramine-N-oxide was the only detected transformation product. Black-Right-Pointing-Pointer Soil-bound residues was a major sink.

  11. South. Afr.J. Educ.Sci.Technol.2(1) (2007)

    African Journals Online (AJOL)

    PNR841, Pennisetum purpureum cvv. Napier SDPP 19 and Bana, Chloris gayana ... Bana, Napier, Sorghum bicolor, Chloris gayana and Cynodon inlemfluensis on the sandy, sandy loam and sandy clay loam soils. On the clay soil, the .... of experimental plots, which included seedbed preparation, planting, weeding and ...

  12. Volatilization of gasoline from soil

    International Nuclear Information System (INIS)

    Arthus, P.

    1993-05-01

    Gasoline contaminated soil threatens water resources and air quality. The extent of the threat depends on gasoline behavior in soil, which is affected by various mechanisms such as volatilization. To quantify volatilization, gasoline spills were simulated in the laboratory using a synthetic gasoline and three dry soils. Total gasoline and individual gasoline compound concentrations in soil were monitored as a function of depth and time. The time to reduce overall gasoline concentration in coarse sand, sandy loam, and silt loam to 40% of initial concentration, averaged between surface and a 200-mm depth, ranged from 0.25 d to 10 d. A wicking phenomenon which contributed to gasoline flux toward the atmosphere was indicated by behavior of a low-volatility gasoline compound. Based on separate wicking experiments, this bulk immiscible movement was estimated at an upward velocity of 0.09 m/d for Delhi sandy loam and 0.05 m/d for Elora silt loam. 70 refs., 24 figs., 34 tabs

  13. The non-steroidal anti-inflammatory drug diclofenac is readily biodegradable in agricultural soils

    Energy Technology Data Exchange (ETDEWEB)

    Al-Rajab, Abdul Jabbar; Sabourin, Lyne [Agriculture and Agri-Food Canada, London, ON, Canada N5V 4T3 (Canada); Lapen, David R. [Agriculture and Agri-Food Canada, Ottawa ON, Canada K1A 0C6 (Canada); Topp, Edward, E-mail: ed.topp@agr.gc.ca [Agriculture and Agri-Food Canada, London, ON, Canada N5V 4T3 (Canada)

    2010-12-01

    Diclofenac, 2-[2-[(2,6-dichlorophenyl)amino]phenyl]acetic acid, is an important non-steroidal anti-inflammatory drug widely used for human and animals to reduce inflammation and pain. Diclofenac could potentially reach agricultural lands through the application of municipal biosolids or wastewater, and in the absence of any environmental fate data, we evaluated its persistence in agricultural soils incubated in the laboratory. {sup 14}C-Diclofenac was rapidly mineralized without a lag when added to soils varying widely in texture (sandy loam, loam, clay loam). Over a range of temperature and moisture conditions extractable {sup 14}C-diclofenac residues decreased with half lives < 5 days. No extractable transformation products were detectable by HPLC. Diclofenac mineralization in the loam soil was abolished by heat sterilization. Addition of biosolids to sterile or non-sterile soil did not accelerate the dissipation of diclofenac. These findings indicate that diclofenac is readily biodegradable in agricultural soils.

  14. The Effects of Land Configuration and Wood-Shavings Mulch on the Properties of a Sandy Loam Soil in Northeast Nigeria. 2. Changes in Physical Properties

    Directory of Open Access Journals (Sweden)

    Chiroma, AM.

    2006-01-01

    Full Text Available Mulching and ridge tillage are proven technologies for improving soil productivity in semi-arid regions. Yet data quantifying the combined influences of these practices are limited. Our objectives were to determine the changes in selected physical properties of a sandy loam after 4-years of annual tillage and wood-shavings mulching. The tillage and wood-shavings treatments consisted of: Flat bed (FB, Open ridge (OR, Tiedridge (TR, FBM, ORM and TRM were same as FB, OR and TR, respectively except that wood-shavings at a rate of 10 t/ha were surface applied ≈ 2 weeks after sowing each year to serve as both a mulch and an organic amendment. At the end of the trial in 2002, bulk density, penetration resistance, total porosity and soil water content from each of 0-0.075, 0.075-0.15 and 0.15-0.30 m depths were determined. Composite samples from the surface (0.075 and 0.075-0.15 m layers from 3 replicates of each treatment were also collected for the determination of wet aggregate stability and from 0-0.15 m and 0.15-0.30 m layers for determination of saturated hydraulic conductivity (Ksat. After 4 years of annual tillage and addition of woodshavings, soil bulk density and penetration resistance were consistently lower and total porosity higher in the FBM, ORM and TRM treatments than in the FB, OR and TR treatments. Penetration resistance in all treatments was strongly related to soil water content. A 'hoe pan' was established below 0.15 m depth beneath the furrows of the ridged treatments. This could be attributed to human traffic during field operations and ponding of water, which occurred in the furrows following heavy rains. Wet aggregate stability estimated as the proportion of aggregates of size > 0.25 mm (macro-aggregates in the 0-0.15 m layer were significantly (P< 0.05 higher under FBM, ORM and TRM than under FB, OR or TR treatments. Ksat was not influenced by either tillage or wood-shavings treatments but were higher for the mulched plots

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

    Science.gov (United States)

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

    2006-03-01

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

  16. CURVAS DE TRANSFERENCIA DE CARGA HORIZONTAL p-y PARA SUELOS LIMOSOS LOÉSSICOS CURVAS DE TRANSFERÊNCIA DE CARGA HORIZONTAL p-y PARA SOLOS LIMOSOS LOÉSSICOS HORIZOTAL LOAD TRANSFERENCE p-y CURVE FOR SILTY LOESS SOILS

    Directory of Open Access Journals (Sweden)

    PEDRO A ARRÚA

    2009-07-01

    a cargas laterais para a construção de curvas de transferência de carga horizontal p-y em condição de umidade natural e saturado. Finalmente, se analisam dois casos de estudo, onde se avalia computacionalmente a resposta de um pilotis instalado em uma camada de limo loéssico que sofre humedecimento localizado. Os resultados mostram a importância de considerar o aumento acidental de umidade no perfil quando os pilotis se encontram instalados em solos de características instáveis.Drilled deep foundations may be subjected to horizontal loads. Under this condition, the behavior analysis is complicated due to the tridimensionality of the problem. H ow ever, the models used in engineering practice often reduce the analysis to two dimensions. In this paper the procedure proposed by Matlock and Reese (1960 is modified for its applicability to loess soils. An alternative to establish the variation of the horizontal subgrade reaction module as a function of depth, for soils with intermediate characteristics between sands and clays, such as silty soils, is developed. An analogy between the cavity expansion and deflection of a pile subjected to lateral loads is established for construction of horizontal charge transfer p-y curves under natural humidity and saturated conditions. Finally, two study cases are analyzed, where the response of pile installed on loess silty soil layer suffering localized wetting is computationally evaluated. Results show the importance of considering the accidental wetting increase, when the piles are installed in unstable soils.

  17. Environmental Assessment for Proposed Demolition and Consolidation, Maxwell Air Force Base, Montgomery County, Alabama

    Science.gov (United States)

    2013-09-01

    51 3.11.2.2 SANITARY SEWER ...............................................................51 3.11.2.3 ELECTRICITY...72 4.2.11.2 SANITARY SEWER ...............................................................73 4.2.11.3...loam or sandy clay soils. The majority of the installation consists of the Amite-Cahaba association which is deep, well-drained, fine sandy loam

  18. Post-Remediation Evaluation of EVO Treatment: How Can We Improve Performance

    Science.gov (United States)

    2017-11-15

    QA/QC Quality Assurance/ Quality Control RAOs Remedial Action Objectives Resolutions Resolutions Consultants SA17 Study Area 17 viii SAP...upper 30 feet of the unconfined aquifer consists of fine sand with multiple discontinuous layers of silty sand , ranging from 1 to over 5 ft thick...Beneath the lower silty sand is a layer of fine to coarse grained sand that extends from 30 to 50 ft bgs. The confining unit of the Hawthorne Group

  19. Interactions between Soil Texture and Placement of Dairy Slurry Application

    DEFF Research Database (Denmark)

    Glæsner, Nadia; Kjærgaard, Charlotte; Rubæk, Gitte Holton

    2011-01-01

    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 μm ranged from 43% in a loamy sand to 28% in a sandy loam and 15% in a loam...... 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...

  20. United States of America Ocean Dumping Report for Calendar Year 1981. Dredged Material.

    Science.gov (United States)

    1982-06-01

    ocean dumping rules and regulations, F.R. Vol 42 No. 7, 11 Jan 1977 (2) Metals: () esame as above(3) Orga& nics : same as above 1). Other :iiLvs.is: (I...results: (1) Nutrients: Meets chemical - biological testing criteria II (2) Metals: * B 1 t U S(3) Orga! nics : b. Other analyses: (1) Metals: (2...description of dredged material, dredging, and transportation made: a. Description: Silty sand to silty clay noncohesive Hydrogen Sulfide smell. BIDDLE b

  1. Interactive effects of vegetation and sediment properties on erosion of salt marshes in the Northern Adriatic Sea.

    Science.gov (United States)

    Lo, V B; Bouma, T J; van Belzen, J; Van Colen, C; Airoldi, L

    2017-10-01

    We investigated how lateral erosion control, measured by novel photogrammetry techniques, is modified by the presence of Spartina spp. vegetation, sediment grain size, and the nutrient status of salt marshes across 230 km of the Italian Northern Adriatic coastline. Spartina spp. vegetation reduced erosion across our study sites. The effect was more pronounced in sandy soils, where erosion was reduced by 80% compared to 17% in silty soils. Erosion resistance was also enhanced by Spartina spp. root biomass. In the absence of vegetation, erosion resistance was enhanced by silt content, with mean erosion 72% lower in silty vs. sandy soils. We found no relevant relationships with nutrient status, likely due to overall high nutrient concentrations and low C:N ratios across all sites. Our results contribute to quantifying coastal protection ecosystem services provided by salt marshes in both sandy and silty sediments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Influence of ageing of residues on the availability of herbicides for leaching

    International Nuclear Information System (INIS)

    Walker, A.; Rodriguez-Cruz, M.S.; Mitchell, M.J.

    2005-01-01

    Losses by leaching of chlorotoluron, isoproturon and triasulfuron from small intact columns of a structured clay loam and an unstructured sandy loam soil were measured in five separate field experiments. In general, losses of all three herbicides were greater from the clay loam than from the sandy loam soil and the order between herbicides was always triasulfuron>>isoproturon>chlorotoluron. Differences between experiments were also consistent for every soil/herbicide combination. There was no relationship between total loss and either total rainfall or cumulative leachate volume. When weighting factors were applied to the rainfall data to make early rainfall more important than later rainfall, there were significant positive relationships between cumulative weighted rainfall and total losses. Also, there were significant negative correlations between total losses and the delay to accumulation of 25 mm rainfall (equivalent to one pore volume of available water) in the different experiments. In laboratory incubations, there was a more rapid decline in aqueous (0.01 M calcium chloride) extractable residues than in total solvent extractable residues indicating increasing sorption with residence time. However, the rate of change in water extractable residues could not completely explain the decrease in leachability with ageing of residues in the field. Short-term sorption studies with aggregates of the two soils indicated slower sorption by those of the clay loam than by those of the sandy loam suggesting that diffusion into and out of aggregates may affect availability for leaching in the more structured soil. Small scale leaching studies with aggregates of the soils also demonstrated reductions in availability for leaching as residence time in soil was increased, which could not be explained by degradation. These results therefore indicate that time-dependent sorption processes are important in controlling pesticide movement in soils, although the data do not give a

  3. Influence of Soil Based Growing Media on Vegetative Propagation of Selected Cultivars of Olea Europaea

    International Nuclear Information System (INIS)

    Ahmed, M. I.; Ashraf, M. I.; Malik, S. U.; Husaain, Q.

    2016-01-01

    Pothwar region of Pakistan is a natural habitat of Olea spp. There is a high demand of certified olive plants to establish olive orchids in the region, because native wild species are non-fruit bearing. Plants of certified fruit bearing olive (Olea europaea L.) cultivars are rarely available. Vegetative propagation of olive is highly responsive to texture of soil based growing media. This study examined the effect of growing media composition (soil texture and nutrients) on vegetative propagation of five cultivars of olive. The experiment was carried out in randomized complete block design (RCBD) with two factors factorial having 25 repeats of each four treatments. Plant growth and survival data were collected and analyzed for the influence of soil attributes. In sandy loam soil, cv. Bari-1 had 82 percent plant survival, highest number of roots per plant (3.5), and longest root length (13.01 cm). Highest number of shoots per plant (4.25) and maximum shoot length (15.64 cm) were also recorded for Bari-1 with sandy loam growing media. Silt loam soil is least suitable growing media for vegetative propagation of olive. In the silt loam soil, plants survival rate was 59 percent for cv. Gemlik, number of roots per plant was 1.5 for cv. Ottobrattica, minimum root length 5.65 cm, minimum number of shoots per plant one, and minimum shoot length 7.42 cm were recorded for cv. Pendolino with silt loam soil. Results suggested that sandy loam growing media is better than the others for vegetative propagation of olive. Cultivar Bari-1 performed better than the others examined in this study by indicating highest (1) survival percentage, (2) root and shoot length, and (3) number of roots and shoots produced within a specific period of time. (author)

  4. Influence of ageing of residues on the availability of herbicides for leaching

    Energy Technology Data Exchange (ETDEWEB)

    Walker, A.; Rodriguez-Cruz, M.S.; Mitchell, M.J

    2005-01-01

    Losses by leaching of chlorotoluron, isoproturon and triasulfuron from small intact columns of a structured clay loam and an unstructured sandy loam soil were measured in five separate field experiments. In general, losses of all three herbicides were greater from the clay loam than from the sandy loam soil and the order between herbicides was always triasulfuron>>isoproturon>chlorotoluron. Differences between experiments were also consistent for every soil/herbicide combination. There was no relationship between total loss and either total rainfall or cumulative leachate volume. When weighting factors were applied to the rainfall data to make early rainfall more important than later rainfall, there were significant positive relationships between cumulative weighted rainfall and total losses. Also, there were significant negative correlations between total losses and the delay to accumulation of 25 mm rainfall (equivalent to one pore volume of available water) in the different experiments. In laboratory incubations, there was a more rapid decline in aqueous (0.01 M calcium chloride) extractable residues than in total solvent extractable residues indicating increasing sorption with residence time. However, the rate of change in water extractable residues could not completely explain the decrease in leachability with ageing of residues in the field. Short-term sorption studies with aggregates of the two soils indicated slower sorption by those of the clay loam than by those of the sandy loam suggesting that diffusion into and out of aggregates may affect availability for leaching in the more structured soil. Small scale leaching studies with aggregates of the soils also demonstrated reductions in availability for leaching as residence time in soil was increased, which could not be explained by degradation. These results therefore indicate that time-dependent sorption processes are important in controlling pesticide movement in soils, although the data do not give a

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

    Science.gov (United States)

    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...

  6. Dissipation and leaching of pyroxasulfone and s-metolachlor

    Science.gov (United States)

    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...

  7. EFFECT OF SOLE AND ASSOCIATIVE ACTIONS OF ELEMENTAL SULFUR AND INOCULATION SULFUR OXIDIZING BACTERIA ON GROWTH AND NUTRIENTS CONTENTS OF PEPPER PLANTS AND THE USED SOILS

    Directory of Open Access Journals (Sweden)

    S. A. Ibrahim

    2011-12-01

    Full Text Available A pot experiment was conducted to study the effect of elemental sulfur (E.S rate (2.5 g/kg soil and sulfur oxidizing bacteria on pepper plant and some chemical properties of two representative soil samples varying in their texture and CaCO3 content. Pepper was grown in Shobrakheet clay loam and Nobaria sandy loam soils for 50 days. Each soil was treated with elemental sulfur (2.5 g kg-1 soil and inoculated with two sulfur oxidizing bacteria (S.O.B. No.8 and S.O.B. ATCC 8158. Elemental sulfur with or without sulfur oxidizing bacteria increased shoot dry weights of pepper plants as compared with control. The highest effect was observed with E.S + ATCC 8158 treatment which resulted in increasing the pepper shoot dry weights from 1.36 to 2.08 g pot-1 with the clay loam soil and from 0.77 to 1.37 g pot-1 with the sandy loam soil. The same treatment resulted in the highest plant content of S, N, P, K and micronutrients.

  8. Analysis of Soil Structure Turnover with Garnet Particles and X-Ray Microtomography.

    Directory of Open Access Journals (Sweden)

    Steffen Schlüter

    Full Text Available Matter turnover in soil is tightly linked to soil structure which governs the heterogeneous distribution of habitats, reaction sites and pathways in soil. Thereby, the temporal dynamics of soil structure alteration is deemed to be important for essential ecosystem functions of soil but very little is known about it. A major reason for this knowledge gap is the lack of methods to study soil structure turnover directly at microscopic scales. Here we devise a conceptual approach and an image processing workflow to study soil structure turnover by labeling some initial state of soil structure with small garnet particles and tracking their fate with X-ray microtomography. The particles adhere to aggregate boundaries at the beginning of the experiment but gradually change their position relative to the nearest pore as structure formation progresses and pores are destructed or newly formed. A new metric based on the contact distances between particles and pores is proposed that allows for a direct quantification of soil structure turnover rates. The methodology is tested for a case study about soil compaction of a silty loam soil during stepwise increase of bulk density (ρ = {1.1, 1.3, 1.5} g/cm3. We demonstrate that the analysis of mean contact distances provides genuinely new insights about changing diffusion pathways that cannot be inferred neither from conventional pore space attributes (porosity, mean pore size, pore connectivity nor from deformation analysis with digital image correlation. This structure labeling approach to quantify soil structure turnover provides a direct analogy to stable isotope labeling for the analysis of matter turnover and can be readily combined with each other.

  9. Use of zeolite to neutralise nickel in a soil environment.

    Science.gov (United States)

    Boros-Lajszner, Edyta; Wyszkowska, Jadwiga; Kucharski, Jan

    2017-12-30

    Nickel is a heavy metal which is a stable soil pollutant which is difficult to remediate. An attempt to reduce its impact on the environment can be made by changing its solubility. The right level of hydrogen ions and the content of mineral and organic colloids are crucial in this regard. Therefore, methods to neutralise heavy metals in soil are sought. There are no reports in the literature on the possibility of using minerals in the detoxication of a soil environment contaminated with metals. It is important to fill the gap in research on the effect of zeolites on the microbiological, biochemical and physicochemical properties of soils under pressure from heavy metals. Therefore, a pot experiment was conducted on two soils which examined the effect of various levels of contamination of soil with nickel on the activity of soil enzymes, physical and chemical properties and growth and development of plants. An alleviating effect of zeolite Bio.Zeo.S.01 on the negative impact of nickel on the soil and a plant (oats) was examined. The enzyme activity and the oat yield were found to be significantly and negatively affected by an excess of nickel in the soil, regardless of the soil type. The metal was accumulated more in the oat roots than in the above-ground parts. An addition of zeolite decreased the level of accumulation of nickel in oats grown only on sandy-silty loam. Zeolite Bio.Zeo.S.01 used in the study only slightly alleviated the negative effect of nickel on the biochemical properties of soil. Therefore, its usability in the remediation of soil contaminated with nickel is small.

  10. Analysis of Soil Structure Turnover with Garnet Particles and X-Ray Microtomography.

    Science.gov (United States)

    Schlüter, Steffen; Vogel, Hans-Jörg

    2016-01-01

    Matter turnover in soil is tightly linked to soil structure which governs the heterogeneous distribution of habitats, reaction sites and pathways in soil. Thereby, the temporal dynamics of soil structure alteration is deemed to be important for essential ecosystem functions of soil but very little is known about it. A major reason for this knowledge gap is the lack of methods to study soil structure turnover directly at microscopic scales. Here we devise a conceptual approach and an image processing workflow to study soil structure turnover by labeling some initial state of soil structure with small garnet particles and tracking their fate with X-ray microtomography. The particles adhere to aggregate boundaries at the beginning of the experiment but gradually change their position relative to the nearest pore as structure formation progresses and pores are destructed or newly formed. A new metric based on the contact distances between particles and pores is proposed that allows for a direct quantification of soil structure turnover rates. The methodology is tested for a case study about soil compaction of a silty loam soil during stepwise increase of bulk density (ρ = {1.1, 1.3, 1.5} g/cm3). We demonstrate that the analysis of mean contact distances provides genuinely new insights about changing diffusion pathways that cannot be inferred neither from conventional pore space attributes (porosity, mean pore size, pore connectivity) nor from deformation analysis with digital image correlation. This structure labeling approach to quantify soil structure turnover provides a direct analogy to stable isotope labeling for the analysis of matter turnover and can be readily combined with each other.

  11. Repeated compost application effects on phosphorus runoff in the Virginia Piedmont.

    Science.gov (United States)

    Spargo, John T; Evanylo, Gregory K; Alley, Marcus M

    2006-01-01

    Increasing amounts of animal and municipal wastes are being composted before land application to improve handling and spreading characteristics, and to reduce odor and disease incidence. Repeated applications of composted biosolids and manure to cropland may increase the risk for P enrichment of agricultural runoff. We conducted field research in 2003 and 2004 on a Fauquier silty clay loam (Ultic Hapludalfs) to compare the effects of annual (since 1999) applications of composted and uncomposted organic residuals on P runoff characteristics. Biosolids compost (BSC), poultry litter-yard waste compost (PLC), and uncomposted poultry litter (PL) were applied based on estimated plant-available N. A commercial fertilizer treatment (CF) and an unamended control treatment (CTL) were also included. Corn (Zea mays L.) and a cereal rye (Secale cereal L.) cover crop were planted each year. We applied simulated rainfall in fall 2004 and analyzed runoff for dissolved reactive P (DRP), total dissolved P (TDP), total P (TP), total organic C (TOC), and total suspended solids (TSS). End of season soil samples were analyzed for Mehlich-3 P (M3P), EPA 3050 P (3050P), water soluble P (WSP), degree of P saturation (DPS), soil C, and bulk density. Compost treatments significantly increased soil C, decreased bulk density, and increased M3P, 3050P, WSP, and DPS. The concentration of DRP, TDP, and TP in runoff was highest in compost treatments, but the mass of DRP and TDP was not different among treatments because infiltration was higher and runoff lower in compost-amended soil. Improved soil physical properties associated with poultry litter-yard waste compost application decreased loss of TP and TSS.

  12. Interactions of tillage and cover crop on water, sediment, and pre-emergence herbicide loss in glyphosate-resistant cotton: implications for the control of glyphosate-resistant weed biotypes.

    Science.gov (United States)

    Krutz, L Jason; Locke, Martin A; Steinriede, R Wade

    2009-01-01

    The need to control glyphosate [N-(phosphonomethyl)glycine]-resistant weed biotypes with tillage and preemergence herbicides in glyphosate-resistant crops (GRCs) is causing a reduction in no-tillage hectarage thereby threatening the advances made in water quality over the past decade. Consequently, if environmental gains afforded by GRCs are to be maintained, then an in-field best management practice (BMP) compatible with tillage is required for hectarage infested with glyphosate-resistant weed biotypes. Thus, 1 d after a preemergent application of fluometuron [N,N-dimethyl-N'-(3-(trifluoromethyl)phenyl)urea] (1.02 kg ha(-1)) and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] (1.18 kg ha(-1)) to a Dundee silt loam (fine-silty, mixed, active, thermic Typic Endoaqualf), simulated rainfall (60 mm h(-1)) was applied to 0.0002-ha microplots for approximately 1.25 h to elucidate tillage (no tillage [NT] and reduced tillage [RT])and cover crop (no cover [NC] and rye cover [RC]) effects on water, sediment, and herbicide loss in surface runoff. Regardless of tillage, RC delayed time-to-runoff 1.3-fold, reduced cumulative runoff volume 1.4-fold, and decreased cumulative sediment loss 4.7-fold. Cumulative fluometuron loss was not affected by tillage or cover crop. Conversely, total metolachlor loss was 1.3-fold lower in NT than RT and 1.4-fold lower in RC than NC. These data indicate that RC can be established in hectarage requiring tillage and potentially curtail water, sediment, and preemergence herbicide losses in the spring to levels equivalent to or better than that of NT, thereby protecting environmental gains provided by GRCs.

  13. Effect of composting and soil type on dissipation of veterinary antibiotics in land-applied manures.

    Science.gov (United States)

    Chen, Chaoqi; Ray, Partha; Knowlton, Katharine F; Pruden, Amy; Xia, Kang

    2018-04-01

    The objective of this study was to determine the fate of commonly used veterinary antibiotics in their naturally excreted form when manure-based amendments are applied to soil. Beef cattle were administered sulfamethazine, tylosin, and chlortetracycline and dairy cows were treated with pirlimycin. The resulting manure was composted for 42 d under static or turned conditions and applied at agronomic N rates to sandy, silt, and silty clay loam soils and compared with amendment with corresponding raw manures in sacrificial microcosms over a 120-day period. Antibiotic dissipation in the raw manure-amended soils followed bi-phasic first order kinetics. The first phase half-lives for sulfamethazine, tylosin, chlortetracycline, and pirlimycin ranged from 6.0 to 18, 2.7 to 3.7, 23 to 25, and 5.5-8.2 d, respectively. During the second phase, dissipation of sulfamethazine was negligible, while the half-lives for tylosin, chlortetracycline, and pirlimycin ranged from 41 to 44, 75 to 144, and 87-142 d, respectively. By contrast, antibiotic dissipation in the compost-amended soils followed single-phase first order kinetics with negligible dissipation of sulfamethazine and half-lives of tylosin and chlortetracycline ranging from 15 to 16 and 49-104 d, respectively. Pirlimycin was below the detection limit in the compost-amended soils. After incubating 120 d, antibiotics in compost-amended soils (up to 3.1 μg kg -1 ) were significantly lower than in manure-amended soils (up to 19 μg kg -1 , p soil type on the dissipation. Risk assessment suggested that composting can reduce antibiotic resistance selection potential in manure-amended soils. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Suitability of soils of the university of Nigeria, Nsukka for the ...

    African Journals Online (AJOL)

    The Nkpologu series of valley bottom, plain and gentle slopes (0-6%) are suitable due to favorable topography, moderately heavy soil textures (sandy clay loam to sandy loam at the topsoil, and sandy clay at the subsoil), and relative soil fertility (with average topsoil % base sat. on the basis of ECEC of 45.08% and O.M. ...

  15. Interactions between Soil Texture and Placement of Dairy Slurry Application

    DEFF Research Database (Denmark)

    Glæsner, Nadia; Kjærgaard, Charlotte; Rubæk, Gitte Holton

    2011-01-01

    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...

  16. Demonstration Report, Munitions Management Projects, ESTCP Project MR-200809, ALLTEM Multi-Axis Electromagnetic Induction System Demonstration and Validation, Aberdeen Proving Ground Standardized UXO Technology Demonstration Site, Version 1.0

    Science.gov (United States)

    2011-11-17

    8217/ ~ O.OOO -~ lOAM "’ "’ 0 > "’ "’ 0 > .O . OSO -~--------------------------------------~~IO~P~M~/’V~~~ .0. !00...j SPM /V 0.050 - ·- ---· SPM 1) ~ 9PM /V ~ o.ooo -IP’ lOAM .o . oso -r-------------------------------------t,.~IO!P~M_l/V~]J .O

  17. Water content estimated from point scale to plot scale

    Science.gov (United States)

    Akyurek, Z.; Binley, A. M.; Demir, G.; Abgarmi, B.

    2017-12-01

    Soil moisture controls the portioning of rainfall into infiltration and runoff. Here we investigate measurements of soil moisture using a range of techniques spanning different spatial scales. In order to understand soil water content in a test basin, 512 km2 in area, in the south of Turkey, a Cosmic Ray CRS200B soil moisture probe was installed at elevation of 1459 m and an ML3 ThetaProbe (CS 616) soil moisture sensor was established at 5cm depth used to get continuous soil moisture. Neutron count measurements were corrected for the changes in atmospheric pressure, atmospheric water vapour and intensity of incoming neutron flux. The calibration of the volumetric soil moisture was performed, from the laboratory analysis, the bulk density varies between 1.719 (g/cm3) -1.390 (g/cm3), and the dominant soil texture is silty clay loam and silt loamThe water content reflectometer was calibrated for soil-specific conditions and soil moisture estimates were also corrected with respect to soil temperature. In order to characterize the subsurface, soil electrical resistivity tomography was used. Wenner and Schlumberger array geometries were used with electrode spacing varied from 1m- 5 m along 40 m and 200 m profiles. From the inversions of ERT data it is apparent that within 50 m distance from the CRS200B, the soil is moderately resistive to a depth of 2m and more conductive at greater depths. At greater distances from the CRS200B, the ERT results indicate more resistive soils. In addition to the ERT surveys, ground penetrating radar surveys using a common mid-point configuration was used with 200MHz antennas. The volumetric soil moisture obtained from GPR appears to overestimate those based on TDR observations. The values obtained from CS616 (at a point scale) and CRS200B (at a mesoscale) are compared with the values obtained at a plot scale. For the field study dates (20-22.06.2017) the volumetric moisture content obtained from CS616 were 25.14%, 25.22% and 25

  18. Interpretation of Seismic Cone Penetration Testing in Silty Soil

    DEFF Research Database (Denmark)

    Holmsgaard, Rikke; Ibsen, Lars Bo; Nielsen, Benjaminn Nordahl

    2016-01-01

    Five Seismic Cone Penetration Tests (SCPT) were conducted at a test site in northern Denmark where the subsoil consists primarily of sandy silt with clay bands. A portion of the test data were collected every 0.5 m to compare the efficacy of closely-spaced down-hole data collection on the computa...

  19. Bioslurping pilot test in a silty low-permeability soil

    International Nuclear Information System (INIS)

    Millette, D.; Thibault, R.; Charlebois, S.; Samson, R.; Orban, H.J.

    1997-01-01

    The efficiency of bioslurping as a remedial technology for hydrocarbon contaminated sites was discussed. Bioslurping combines the two remedial technologies of bioventing and vacuum-enhanced free-product recovery. Bioslurping does not require a cone of depression in the groundwater table around a well to draw the light non-aqueous phase liquid (LNAPL) contaminant to the well. LNAPLs are recovered by applying a low to medium vacuum on the recovery wells. The rate of LNAPL recovery is higher with bioslurping than with a dual-pump system. A 26-day bioslurping pilot study was conducted at a decommissioned Montreal gas station contaminated by gasoline. The site was on soil composed mainly of silt. The depth of hydrocarbons measured was 1.17 m. Bioslurping was capable of removing about 50 kg/day per well of hydrocarbons from this site. The bulk of the product extracted was in the form of vapors. The cost associated with the treatment of air emissions could be reduced by partial reinjection within the radius of influence of the slurping wells. The indigenous microbial population was able to biodegrade the hydrocarbons. About eight per cent of the total mass of hydrocarbons was eliminated by biodegradation. 13 refs., 5 tabs., 11 figs

  20. Anchorage Behaviors of Frictional Tieback Anchors in Silty Sand

    Science.gov (United States)

    Hsu, Shih-Tsung; Hsiao, Wen-Ta; Chen, Ke-Ting; Hu, Wen-Chi; Wu, Ssu-Yi

    2017-06-01

    Soil anchors are extensively used in geotechnical applications, most commonly serve as tieback walls in deep excavations. To investigate the anchorage mechanisms of this tieback anchor, a constitutive model that considers both strain hardening and softening and volume dilatancy entitled SHASOVOD model, and FLAC3D software are used to perform 3-D numerical analyses. The results from field anchor tests are compared with those calculated by numerical analyses to enhance the applicability of the numerical method. After the calibration, this research carried out the parameter studies by numerical analyses. The numerical results reveal that whether the yield of soil around an anchor develops to ground surface and/or touches the diaphragm wall depending on the overburden depth H and the embedded depth Z of an anchor, this study suggests the minimum overburden and embedded depths to avoid the yield of soils develop to ground surface and/or touch the diaphragm wall. When the embedded depth, overburden depth or fixed length of an anchor increases, the anchorage capacity also increases. Increasing fixed length should be the optimum method to increase the anchorage capacity for fixed length less than 20m. However, when the fixed length of an anchor exceeds 30 m, the increasing rate of anchorage capacity per fixed length decreases, and progressive yield occurs obviously between the fixed length and surrounding soil.

  1. Soil physical effects on longleaf pine performance in the West Gulf Coastal Plain

    Science.gov (United States)

    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...

  2. Effects of soil physical properties on erodibility and infiltration ...

    African Journals Online (AJOL)

    The soil moisture count for plot A ranged between 9.54% to 14.56% while that of plot B range between 10.64% to 11.26%. The particle sizes analysis indicated that the soil type in plot A is mainly medium loam and predominantly sand clay loam in plot B. It is therefore concluded that, the study area is susceptible to erosion ...

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

    Science.gov (United States)

    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%...

  4. Adsorption and desorption study of 14C-Chloropyrifos in two Malaysian agricultural soils

    International Nuclear Information System (INIS)

    Halimah Muhammad; Nashriyah Mat; Tan Yew Ai; Ismail, B.S.

    2004-01-01

    The adsorption equilibrium time and effects of pH and concentration of 14 C-labeled chloropyrifos 0,0-diethyl 0-(3, 5, 6 tricloro-2-pyridyl)-phosphorothiote in soil were investigated. Two types of Malaysian soil under oil palm were used in this study; namely clay loam and clay soil obtained from the Sungai Sedu and Kuala Lumpur International Airport (KLIA) Estates, respectively. Equilibrium studies of chloropyrifos between the agricultural soil and the pesticide solution were conducted. Adsorption equilibrium time was achieved within 6 and 24 hours for clay loam and clay soil, respectively. It was found that chloropyrifos adsorbed by the soil samples was characterized by an initial rapid adsorption after which adsorption remained approximately constant. The percentage of 14 C-labeled chloropyrifos adsorption on soil was found to be higher in clay loam than in clay soils. Results of the study demonstrated that pH affected the adsorption of chloropyrifos on both clay loam and clay soils. The adsorption of chloropyrifos on both types of soil was higher at low pH with the adsorption reduced as the pH increased. Results also suggest that chloropyrifos sorption by soil is concentration dependent. (Author)

  5. Performance of two bioswales on urban runoff management

    Science.gov (United States)

    Qingfu Xiao; E. McPherson; Qi Zhang; Xinlei Ge; Randy Dahlgren

    2017-01-01

    This study evaluated the effectiveness of two bioswales eight years after construction in Davis, California. The treatment bioswale measured 9 m × 1 m × 1 m (L × W × D). Engineered soil mix (75% native lava rock and 25% loam soil) replaced the native loam soil. Four Red Tip Photinia (Photinia × fraseri Dress) trees and two Blueberry Muffin Hawthorn...

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

    Science.gov (United States)

    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

  7. Geotechnical maps for recommendation on bored pile capacity in Nakhon Ratchasima municipality, Thailand

    Directory of Open Access Journals (Sweden)

    Suksun Horpibulsuk

    2013-08-01

    Full Text Available This paper presents the development of geotechnical maps in Nakhon Ratchasima municipality, Nakhon Ratchasima province, Thailand based on the boring logs and in situ test results collected from public and private sector sources. The standard penetration number, N was used to identify the soil type. The soil deposits in Nakhon Ratchasima municipality are divided into three layers: medium-to-stiff silty clay with N 50. The medium-to-stiff silty clay layer has a thickness varying from 1.8 to 7.5 metres and an average N value of 14 with a relatively low standard deviation of 1.08. The first hard silty clay layer has a thickness varying from 1.2 to 3.0 metres and an average N value of 42 with a standard deviation of 1.37. For a practical application in foundation engineering in which the pile tips of the bored piles are located in the second hard stratum with N > 50, eight pile tip zones with approximated load capacity are recommended for pile lengths of 3-10 metres.

  8. Impact of Incremental Sampling Methodology (ISM) on Metals Bioavailability

    Science.gov (United States)

    2016-05-01

    Analysis Date Ca K Na Mg P Si (mg/kg) BL-1B Background Loam 0.61 Sieved >2 mm 4013004-05 29-Jan-14 30-Jan-14 1330 601 24 9570 396 21 BL-1AUa... analysis of soil. In contrast, L. rigidum grown in loam had much lower recoverable lead. Milling of the soil as part of the ISM process had no...19 3.4.6 Metals analysis

  9. Environmental Assessment Newport Research Facility Irish Hill

    Science.gov (United States)

    2011-09-12

    Classification Symbol Burdett silt loam, 3 to 8 percent BuB Not Hydric Prime Farmland if Drained slopes Honeoye and Lansing silt loams, Hre Not...Part USDA - llap unit symbol BuB ~ CsB HrE HsD HIB HtC LnC LnD McB MIS ~ MoB I MoD NaB NaC NaD I 1R0 •ShF llap unit Mille Rating

  10. Fate of the antiretroviral drug tenofovir in agricultural soil

    Energy Technology Data Exchange (ETDEWEB)

    Al-Rajab, Abdul Jabbar; Sabourin, Lyne; Chapman, Ralph; Lapen, David R.; Topp, Edward, E-mail: ed.topp@agr.gc.ca [Agriculture and Agri-Food Canada, London, ON, N5V 4T3 (Canada)

    2010-10-15

    Tenofovir (9-(R)-(2-phosphonylmethoxypropyl)-adenine) is an antiretroviral drug widely used for the treatment of human immunodeficiency virus (HIV-1) and Hepatitis B virus (HBV) infections. Tenofovir is extensively and rapidly excreted unchanged in the urine. In the expectation that tenofovir could potentially reach agricultural lands through the application of municipal biosolids or wastewater, and in the absence of any environmental fate data, we evaluated its persistence in selected agricultural soils. Less than 10% of [adenine-8-{sup 14}C]-tenofovir added to soils varying widely in texture (sand, loam, clay loam) was mineralized in a 2-month incubation under laboratory conditions. Tenofovir was less readily extractable from clay soils than from a loam or a sandy loam soil. Radioactive residues of tenofovir were removed from the soil extractable fraction with DT{sub 50}s ranging from 24 {+-} 2 to 67 + 22 days (first order kinetic model) or 44 + 9 to 127 + 55 days (zero order model). No extractable transformation products were detectable by HPLC. Tenofovir mineralization in the loam soil increased with temperature (range 4 {sup o}C to 30 {sup o}C), and did not occur in autoclaved soil, suggesting a microbial basis. Mineralization rates increased with soil moisture content, ranging from air-dried to saturated. In summary, tenofovir was relatively persistent in soils, there were no extractable transformation products detected, and the response of [adenine-8-{sup 14}C]-tenofovir mineralization to soil temperature and heat sterilization indicated that the molecule was biodegraded by aerobic microorganisms. Sorption isotherms with dewatered biosolids suggested that tenofovir residues could potentially partition into the particulate fraction during sewage treatment.

  11. Spatial Variability of Soil Physical Properties Obtained with Laboratory Methods and Their Relation to Field Electrical Resistivity Measurements

    Science.gov (United States)

    Dathe, A.; Nemes, A.; Bloem, E.; Patterson, M.; Gimenez, D.; Angyal, A.; Koestel, J. K.; Jarvis, N.

    2017-12-01

    Soil spatial heterogeneity plays a critical role for describing water and solute transport processes in the unsaturated zone. Although we have a sound understanding of the physical properties underlying this heterogeneity (like macropores causing preferential water flow), their quantification in a spatial context is still a challenge. To improve existing knowledge and modelling approaches we established a field experiment on an agriculturally used silty clay loam (Stagnosol) in SE Norway. Centimeter to decimeter scale heterogeneities were investigated in the field using electrical resistivity tomography (ERT) in a quasi-3D and a real 3D approach. More than 100 undisturbed soil samples were taken in the 2x1x1 m3plot investigated with 3D ERT to determine soil water retention, saturated and unsaturated hydraulic conductivities and bulk density in the laboratory. A subset of these samples was scanned at the computer tomography (CT) facility at the Swedish University of Agricultural Sciences in Uppsala, Sweden, with special emphasis on characterizing macroporosity. Results show that the ERT measurements captured the spatial distribution of bulk densities and reflected soil water contents. However, ERT could not resolve the large variation observed in saturated hydraulic conductivities from the soil samples. Saturated hydraulic conductivity was clearly related to the macroporosity visible in the CT scans obtained from the respective soil cores. Hydraulic conductivities close to saturation mainly changed with depths in the soil profile and therefore with bulk density. In conclusion, to quantify the spatial heterogeneity of saturated hydraulic conductivities scanning methods with a resolution smaller than the size of macropores have to be used. This is feasible only when the information obtained from for example CT scans of soil cores would be upscaled in a meaningful way.

  12. Vinasse application to sugar cane fields. Effect on the unsaturated zone and groundwater at Valle del Cauca (Colombia).

    Science.gov (United States)

    Ortegón, Gloria Páez; Arboleda, Fernando Muñoz; Candela, Lucila; Tamoh, Karim; Valdes-Abellan, Javier

    2016-01-01

    Extensive application of vinasse, a subproduct from sugar cane plantations for bioethanol production, is currently taking place as a source of nutrients that forms part of agricultural management in different agroclimatic regions. Liquid vinasse composition is characterised by high variability of organic compounds and major ions, acid pH (4.7), high TDS concentration (117,416-599,400mgL(-1)) and elevated EC (14,350-64,099μScm(-1)). A large-scale sugar cane field application is taking place in Valle del Cauca (Colombia), where monitoring of soil, unsaturated zone and the aquifer underneath has been made since 2006 to evaluate possible impacts on three experimental plots. For this assessment, monitoring wells and piezometers were installed to determine groundwater flow and water samples were collected for chemical analysis. In the unsaturated zone, tensiometers were installed at different depths to determine flow patterns, while suction lysimeters were used for water sample chemical determinations. The findings show that in the sandy loam plot (Hacienda Real), the unsaturated zone is characterised by low water retention, showing a high transport capacity, while the other two plots of silty composition presented temporal saturation due to La Niña event (2010-2011). The strong La Niña effect on aquifer recharge which would dilute the infiltrated water during the monitoring period and, on the other hand dissolution of possible precipitated salts bringing them back into solution may occur. A slight increase in the concentration of major ions was observed in groundwater (~5% of TDS), which can be attributed to a combination of factors: vinasse dilution produced by water input and hydrochemical processes along with nutrient removal produced by sugar cane uptake. This fact may make the aquifer vulnerable to contamination. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Brackish water for irrigation: IV. effects on yield of maize (zea mays l.) and saturated hydraulic conductivity of soil

    International Nuclear Information System (INIS)

    Abid, M.; Anwar-ur-Hassan; Ghafoor, A.

    2003-01-01

    The experiment was conducted to investigate the effect of brackish water irrigation on fresh biomass yield of maize variety Agati-72 and saturated hydraulic conductivity (HC) of silty clay loam soil. Total 20 treatment combinations having different EC/sub iw/ (0.65, 2.0, 4.0, 6.0 and 7.35 dS m/sup -1/), SAR/sub iw/ (3.95, 9.65, 18.0, 26.35 and 32.04 (mmol L/sup -1)/sup 1/2/) and RSC (0.65, 2.0, 4.0, 6.0 and 7.35 mmol/sub c/ L/sup -1/) were applied to 30 cm x 68 cm undisturbed and disturbed soil columns. Results indicated that biomass yield of maize decreased with an increase in EC/sub iw/ from 0.65 to 7.35 dS m/sup -1/ at coded 0 levels of SAR/sub iw/ and RSC in undisturbed soil. The maize tolerated EC/sub iw/ up to 2.0 dS m/sup-1/ at coded 0 levels of SAR/sub iw/ and RSC in disturbed soil. The SAR/sub iw/ up to 18.0 did not affect the yield of crop at coded 0 levels of EC/sub iw/ for the undisturbed and disturbed soils, respectively. The increase in HC was 48% in undisturbed and 54% in disturbed soils with EC/sub iw/ 7.35 dS m/sup -1/ over EC/sub iw/ 0.65 dS m/sup -1/ coded 0 levels of EC/sub iw/ and RSC. The HC decreased with SAR/sub iw/ and RSC at coded 0 levels of EC/sub iw/ and RSC; EC/sub iw/ and SAR/sub iw/ in both the soil columns. (author)

  14. UNA NUEVA ALTERNATIVA NUMÉRICA PARA LA SOLUCIÓN DE LA ECUACIÓN UNIDIMENSIONAL DE RICHARDS: ESTUDIO DE DRENAJE E INFILTRACIÓN DE FLUIDOS EN LA ZONA NO SATURADA

    Directory of Open Access Journals (Sweden)

    Evelyn Álvarez Sierra

    2016-10-01

    Full Text Available En el trabajo se comparan dos métodos numéricos para resolver el modelo unidimensional de infiltración y drenaje de agua en la zona no saturada en medios porosos, el cual es modelado respecto al contenido de humedad utilizando la ecuación no-lineal de Richards. El primer método está basado en el método clásico de Diferencias Finitas y el segundo en el método de Líneas combinado con el código DASSL para la solución de las ecuaciones diferenciales-algebraicas resultantes. Se muestra que el último método proporciona una vía numérica eficiente para la solución de problemas de EDPs que tienen un comportamiento singular de shock u ondas viajeras, como es el caso de la ecuación de Richard, los cuales se pueden resolver numéricamente con éxito sólo utilizando esquemas muy estables. Los métodos numéricos discutidos en el trabajo se aplican a dos tipos de suelos reales: Yolo Light Clay y Brindabella Silty Clay Loam, usando las propiedades hidráulicas referidas en Broadbridge y White [16]. Para validar el modelo, se comparan los perfiles de humedad con los resultados reportados por Warrick, Lomen e Islas [18].Igualmente, se demuestra con datos reales la ventaja de resolver numéricamente el comportamiento del flujo unidimensional en la zona no saturada de un medio poroso. Finalmente, el modelo propuesto y los resultados numéricos obtenidos posibilitan brindar un pronóstico sobre la utilización de recursos hídricos para el caso de riego en agricultura y también para el transporte de contaminantes.

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

    Science.gov (United States)

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

    2009-01-01

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

  16. Evaluating equilibrium and non-equilibrium transport of bromide and isoproturon in disturbed and undisturbed soil columns

    Science.gov (United States)

    Dousset, S.; Thevenot, M.; Pot, V.; Šimunek, J.; Andreux, F.

    2007-12-01

    In this study, displacement experiments of isoproturon were conducted in disturbed and undisturbed columns of a silty clay loam soil under similar rainfall intensities. Solute transport occurred under saturated conditions in the undisturbed soil and under unsaturated conditions in the sieved soil because of a greater bulk density of the compacted undisturbed soil compared to the sieved soil. The objective of this work was to determine transport characteristics of isoproturon relative to bromide tracer. Triplicate column experiments were performed with sieved (structure partially destroyed to simulate conventional tillage) and undisturbed (structure preserved) soils. Bromide experimental breakthrough curves were analyzed using convective-dispersive and dual-permeability (DP) models (HYDRUS-1D). Isoproturon breakthrough curves (BTCs) were analyzed using the DP model that considered either chemical equilibrium or non-equilibrium transport. The DP model described the bromide elution curves of the sieved soil columns well, whereas it overestimated the tailing of the bromide BTCs of the undisturbed soil columns. A higher degree of physical non-equilibrium was found in the undisturbed soil, where 56% of total water was contained in the slow-flow matrix, compared to 26% in the sieved soil. Isoproturon BTCs were best described in both sieved and undisturbed soil columns using the DP model combined with the chemical non-equilibrium. Higher degradation rates were obtained in the transport experiments than in batch studies, for both soils. This was likely caused by hysteresis in sorption of isoproturon. However, it cannot be ruled out that higher degradation rates were due, at least in part, to the adopted first-order model. Results showed that for similar rainfall intensity, physical and chemical non-equilibrium were greater in the saturated undisturbed soil than in the unsaturated sieved soil. Results also suggested faster transport of isoproturon in the undisturbed soil due

  17. Effects of cadmium amendments on low-molecular-weight organic acid exudates in rhizosphere soils of tobacco and sunflower.

    Science.gov (United States)

    Chiang, Po-Neng; Wang, Ming Kuang; Chiu, Chih Yu; Chou, Shu-Yen

    2006-10-01

    To recognize physiological response of plants to cadmium (Cd) toxicity in rhizosphere of plants, the pot experiments were employed to investigate how low-molecular-weight organic acids (LMWOAs) were exudated from tobacco and sunflower roots of Cd-amended soils. The aims of this study were to assess the effect of LMWOAs on uptake of Cd by tobacco and sunflower under pot experiments, thus comparing the ability of tobacco and sunflower for phytoremediation. Surface soils (0-20 cm) were collected from Taichung Experiment Station (TC) (silty loam). Cadmium chloride (CdCl(2)) was amended into TC soil, giving Cd concentrations of 1, 5, 10 mg kg(-1) soil. Soils with different concentrations of Cd were put into 12 cm (i.d.) pots for incubation, and then 2-week-old tobacco and sunflower seedlings were transplanted into the pots. Tobacco and sunflower were grown in greenhouse for 50 days, respectively. The rhizosphere and bulk soils, and fresh plant tissues were collected after harvest. The Cd concentrations in the plant and transfer factor values in the sunflower were higher than that in the tobacco. No LMWOAs were detected by gas chromatograph in bulk soils, and low amounts of LMWOAs were found in uncontaminated rhizosphere soils. Acetic, lactic, glycolic, malic, maleic, and succinic acids were found in the tobacco and sunflower rhizosphere soils. Concentrations of LMWOAs increased with increasing amendment of Cd concentrations in tobacco and sunflower rhizosphere soils. Correlation coefficient (r) of concentrations of Cd amendment versus LMWOAs exudates of tobacco and sunflower were 0.85 and 0.98, respectively. These results suggest that the different levels of LMWOAs present in the rhizosphere soil play an important role in the solubilization of Cd that bound with soil particle into soil solution and then uptake by plants.

  18. Elucidating the impact of nitrate and labile carbon application on spatial heterogeneity of denitrification by 15N modelling

    Science.gov (United States)

    Cardenas, Laura; Loick, Nadine; Dixon, Liz; Matthews, Peter; Gilsanz, Claudia; Bol, Roland; Lewicka-Szczebak, Dominika; Well, Reinhard

    2016-04-01

    N2O is considered to be an important GHG with soils representing its major source and accounting for approximately 6% of the current global warming and is also implicated in the depletion of stratospheric ozone. The atmospheric N2O concentration has been increasing since the Industrial Revolution making the understanding of its sources and removal processes very important for development of mitigation strategies. Bergstermann et al. (2011) found evidence of the existence of more than one pool of nitrate undergoing denitrification in a silty clay loam arable soil amended with glucose/nitrate solution. The Rayleigh type model was used to simulate d15N of N2O using process rates and associated fractionation factors, but assumptions for some of the model parameters had to be made due to lack of available data. In this study we carried out 2 incubation experiments in order to parameterise the model. To restrict the volume of soil reached by the amendment, we used blocks containing 3 soil cores that were incubated in one vessel to measure emissions of NO, N2O, N2 and CO2 from a clay grassland soil amended with KNO3 (N) and glucose (C) in three treatments: '1C' only 1 core received N and C (the other 2 received water), '3C' 3 cores received N and C, and 'Control' (received water only). The results showed changes in the d15Nbulk trends after day 6 post amendment application, coinciding with the decrease of N2O fluxes. We also report the results in the 15N site preference (SP) and d18O. We will show the results from the model validation based on this data.

  19. Modeling Phytoremediation of Cadmium Contaminated Soil with Sunflower (Helianthus annus) Under Salinity Stress

    International Nuclear Information System (INIS)

    Motesharezadeh, B.; Navabzadeh, M.; Liyaghat, A. M.

    2016-01-01

    This study was carried out as a factorial experiment with 5 levels of cadmium (Cd) (o, 25, 50, 75, and 100 mg/kg), 5 levels of salinity (Control, 4, 5, 6, and 7 dS/m), and two soil textures (sandy loam and clay loam). The results showed that the amount of Cd in root and shoot of sunflower increased as soil salinity and Cd concentration increased. The best concentrations for Cd phytoremediation were 75 mg/kg in sandy loam and 100 mg/kg in clay loam. Mass-Hoffman model in simulating transpiration Cd stress as well as Homaee model in simulating salt stress indicated the best results in light soils. By multiplying the salinity stress model by Cd stress model, the simultaneous model for each soil was calculated. These models in light soil (r2=0.68) and heavy soil (r2=0.81) were compatible with measured values. In the heavy soil, absorbed Cd by plant along with increased salinity reflected low changes, but changes in Cd absorbed by plants in the heavy soil were more uniform than in the light soil. In conclusion, for estimating the Cd uptake, the model had a better performance in the heavy soil (under salt stress).

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

    Science.gov (United States)

    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.

  1. Amounts of mercury in soil of some golf course sites

    Energy Technology Data Exchange (ETDEWEB)

    MacLean, A J; Stone, B; Cordukes, W E

    1973-01-01

    Mercurial compounds are widely used for controlling diseases of turfgrass of golf courses, but the fungicides are usually confined to the greens. Composite soil samples were obtained from three golf courses in the Ottawa and Ontario region of Canada. Samples from the turf and surface layer of soil were analyzed and high amounts of mercury were found. The soil of No.I course was a sand; No.II was a sandy loam in the surface and a loam below; and No. III was a loam in the surface layer and a clay loam below. The pH of the surface layer was 6.4 in No. I, 7.5 in No. II, and 6.0 in No. III. The amounts of Hg in the turf were high near the green but they decreased with distance. Fairway III contained the highest amounts of Hg and there was evidence of it leaching to a depth of 90 cm at the edge of the green. The particularly high amounts of Hg in no III were in accord with the liberal use of mercurial fungicides on this course in the period 1912-64. The leaching of Hg depends on amounts of organic matter and the clay in the soil.

  2. Adsorption-Desorption of Hexaconazole in Soils with Respect to Soil Properties, Temperature, and pH

    Directory of Open Access Journals (Sweden)

    Maznah Zainol

    2016-06-01

    Full Text Available The effect of temperature and pH on adsorption-desorption of fungicide hexaconazole was studied in two Malaysian soil types; namely clay loam and sandy loam. The adsorption-desorption experiment was conducted using the batch equilibration technique and the residues of hexaconazole were analysed using the GC-ECD. The results showed that the adsorption-desorption isotherms of hexaconazole can be described with Freundlich equation. The Freundlich sorption coefficient (Kd values were positively correlated to the clay and organic matter content in the soils. Hexaconazole attained the equilibrium phase within 24 h in both soil types studied. The adsorption coefficient (Kd values obtained for clay loam soil and sandy loam soil were 2.54 mL/g and 2.27 mL/g, respectively, indicating that hexaconazole was weakly sorbed onto the soils due to the low organic content of the soils. Regarding thermodynamic parameters, the Gibb’s free energy change (ΔG analysis showed that hexaconazole adsorption onto soil was spontaneous and exothermic, plus it exhibited positive hysteresis. A strong correlation was observed between the adsorption of hexaconazole and pH of the soil solution. However, temperature was found to have no effect on the adsorption of hexaconazole onto the soils; for the range tested.

  3. Effects of Field Conditions on Emergence of Oilseed Rape Seed lots Grown in Khorasan Province

    Directory of Open Access Journals (Sweden)

    A Yanegh

    2014-07-01

    Full Text Available Nineteen irrigated farms of canola from six cities of Khorasan selected to assess the seedling emergence one month after sowing in 2009. Soil texture of each farm determined using the Hydrometer method. The results showed that weather conditions of sowing areas had no significant effect on emergence of oilseed rape. With increasing the temperature (within the range of 19.5 to 21.5 ˚C emergence percentage was not increased significantly. Rainfall also caused no significant effect on seedling emergence. The percentage of emergence in machine-sowing and hand-sowing were 38.4% and 28%, respectively. Soils with loam silt, silt clay loam and loam texture had emergence of 27.2%, 31.2% and 47% respectively. It seems soil texture plays a great roll on the emergence of oilseed rape with epigeal seedlings.

  4. Proceedings of the International Symposium on Frozen Soil Impacts on Agricultural, Range, and Forest Lands Held at Spokane, Washington on March 21-22, 1990

    Science.gov (United States)

    1990-03-01

    the United States. The soils were: a Cecil sandy loam (clayey, kaolinitic, thermic Typic Hapludult) from Watkinsville, GA ; a Barnes loam (fine loamy...1987). GLEAMS user manual. Lab Note South East Watershed Research Laboratory 110 187 WGK, Tifton , Ge, 1987. Lane, L.J., and V. A. Ferreira, (1980...as caps for processed uranium mill tailings in the western United States. The purpose of these barriers is to control radon gas release. The soil

  5. Rhizosphere organic anions play a minor role in improving crop species’ ability to take up residual phosphorus (P in agricultural soils low in P availability

    Directory of Open Access Journals (Sweden)

    Yanliang Wang

    2016-11-01

    Full Text Available Many arable lands have accumulated large reserves of residual phosphorus (P and a relatively large proportion of soil P is less available for uptake by plants. Root released organic anions are widely documented as a key physiological strategy to enhance P availability, while limited information has been generated on the contribution of rhizosphere organic anions to P utilization by crops grown in agricultural soils that are low in available P and high in extractable Ca, Al and Fe. We studied the role of rhizosphere organic anions in P uptake from residual P in four common crops Triticum aestivum, Avena sativa, Solanum tuberosum and Brassica napus in low- and high-P availability agricultural soils from long-term fertilization field trials in a mini-rhizotron experiment with four replications. Malate was generally the dominant organic anion. More rhizosphere citrate was detected in low P soils than in high P soil. Brassica napus showed 74-103% increase of malate in low P loam, compared with clay loam. Avena sativa had the greatest rhizosphere citrate concentration in all soils (5.3-15.2 mol g-1 root DW. Avena sativa also showed the highest level of root colonization by arbuscular mycorrhizal fungi (36% and 40%, the greatest root mass ratio (0.51 and 0.66 in the low-P clay loam and loam respectively, and the greatest total P uptake (5.92 mg P/mini-rhizotron in the low-P loam. Brassica napus had 15-44% more rhizosphere APase activity, ~0.1-0.4 units lower rhizosphere pH than other species, the greatest increase in rhizosphere water-soluble P in the low-P soils, and the greatest total P uptake in the low-P clay loam. Shoot P content was mainly explained by rhizosphere APase activity, water-soluble P and pH within low P soils across species. Within species, P uptake was mainly linked to rhizosphere water soluble P, APase and pH in low P soils. The effects of rhizosphere organic anions varied among species and they appeared to play minor roles in

  6. Rhizosphere Organic Anions Play a Minor Role in Improving Crop Species' Ability to Take Up Residual Phosphorus (P) in Agricultural Soils Low in P Availability.

    Science.gov (United States)

    Wang, Yanliang; Krogstad, Tore; Clarke, Jihong L; Hallama, Moritz; Øgaard, Anne F; Eich-Greatorex, Susanne; Kandeler, Ellen; Clarke, Nicholas

    2016-01-01

    Many arable lands have accumulated large reserves of residual phosphorus (P) and a relatively large proportion of soil P is less available for uptake by plants. Root released organic anions are widely documented as a key physiological strategy to enhance P availability, while limited information has been generated on the contribution of rhizosphere organic anions to P utilization by crops grown in agricultural soils that are low in available P and high in extractable Ca, Al, and Fe. We studied the role of rhizosphere organic anions in P uptake from residual P in four common crops Triticum aestivum, Avena sativa, Solanum tuberosum , and Brassica napus in low- and high-P availability agricultural soils from long-term fertilization field trials in a mini-rhizotron experiment with four replications. Malate was generally the dominant organic anion. More rhizosphere citrate was detected in low P soils than in high P soil. B. napus showed 74-103% increase of malate in low P loam, compared with clay loam. A. sativa had the greatest rhizosphere citrate concentration in all soils (5.3-15.2 μmol g -1 root DW). A. sativa also showed the highest level of root colonization by arbuscular mycorrhizal fungi (AMF; 36 and 40%), the greatest root mass ratio (0.51 and 0.66) in the low-P clay loam and loam respectively, and the greatest total P uptake (5.92 mg P/mini-rhizotron) in the low-P loam. B. napus had 15-44% more rhizosphere acid phosphatase (APase) activity, ~0.1-0.4 units lower rhizosphere pH than other species, the greatest increase in rhizosphere water-soluble P in the low-P soils, and the greatest total P uptake in the low-P clay loam. Shoot P content was mainly explained by rhizosphere APase activity, water-soluble P and pH within low P soils across species. Within species, P uptake was mainly linked to rhizosphere water soluble P, APase, and pH in low P soils. The effects of rhizosphere organic anions varied among species and they appeared to play minor roles in

  7. The role of herbaceous crops in soil carbon and nitrogen cycles in relation to soil management . methodological approaches and innovative technologies

    International Nuclear Information System (INIS)

    Mohamed, M.A.A.

    2010-01-01

    stable. In this study the isotopic signature of a series of soils collected throughout Italy was determined before and after eliminating carbonates The field experiment was conducted during the growing seasons 2007 and 2008 at the Agronomic Institute, for industrial crop (ISCI) Battipaglia Italy cooperation with International PhD Crop Systems, Forestry, and Environmental Sciences university of Basilicata - Southern Italy on a Pachic Phaeozems (PHph) (WRB-FAO) soil which was classified as Silty Clay Loam from 0 to 0.30 m depth and a Silty Clay from 0.30 to 1.20 m depth. The studied crop was sorghum Sorghum bicolor Moench x S. sudanense (Piper) Stapf.(BMR333), planted by hand in rows during the first season 2007 on 31 May with density of 20 plant/m 2 and on 14 June 2008

  8. Bioremediation Potential of Terrestrial Fuel Spills †

    OpenAIRE

    Song, Hong-Gyu; Wang, Xiaoping; Bartha, Richard

    1990-01-01

    A bioremediation treatment that consisted of liming, fertilization, and tilling was evaluated on the laboratory scale for its effectiveness in cleaning up a sand, a loam, and a clay loam contaminated at 50 to 135 mg g of soil−1 by gasoline, jet fuel, heating oil, diesel oil, or bunker C. Experimental variables included incubation temperatures of 17, 27, and 37°C; no treatment; bioremediation treatment; and poisoned evaporation controls. Hydrocarbon residues were determined by quantitative gas...

  9. Effect of Aggregate Structure on VOC Gas Adsorption onto Volcanic Ash Soil

    OpenAIRE

    濱本, 昌一郎

    2008-01-01

    The understanding of the gaseous adsorption process and the parameters of volatile organic compounds such as organic solvents or fuels onto soils is very important in the analysis of the transport or fate of these chemicals in soils. Batch adsorption experiments with six different treatments were conducted to determine the adsorption of isohexane, a gaseous aliphatic, onto volcanic ash soil (Tachikawa loam). The measured gas adsorption coefficient for samples of Tachikawa loam used in the fir...

  10. A Study on the Autecology of Reseda lutea L. (Resedaceae) Distributed in Western Anatolia

    OpenAIRE

    DOĞAN, Yunus

    2014-01-01

    The aim of this study was to determine the autecological characteristics of Reseda lutea L. (Resedaceae) distributed in Western Anatolia. The chemical and physical analysis was carried out on soil and plant samples collected from 54 different localities in Western Anatolia. The results show that the plant generally prefers sandy-loam and sandy-clayey-loam textural soils, with a slightly alkaline or medium alkaline pH. They prefer non-saline, calcareous soils which are poor in potassium and ph...

  11. Caracterización y modelación del transporte preferencial de plaguicidas organofosforados en suelos productivos bajo riego. Aplicación al Distrito Colonia Centenario, Patagonia Argentina.

    OpenAIRE

    DUFILHO, ANA CECILIA AMALIA

    2016-01-01

    [EN] In this thesis, transport and fate of organophosphate pesticides - azinphos-methyl and chlorpyrifos- in productive soils from the valley of the Neuquén River in the Patagonia Argentina are analysed. Climate of the region is arid, so traditional fruit production is under flood irrigation. The soils in the floodplain are predominant Aridisols with textures from sandy loam to clay loam. Methodologically, the thesis was based on: field experiments and data and information processing condu...

  12. A Comparative Study of the Persistence, Movement and Metabolism of Six Insecticides in Soils and Plants

    International Nuclear Information System (INIS)

    Fuhremann, T.W.; Lichtenstein, E.P.

    1981-01-01

    Full text: Two soil types and oat plants grown in these soils were incubated under identical environmental conditions. The insecticides used in order to increase the water solubility were 14 C-DDT, 14 C-lindane, 14 C-fonofos, 14 C-parathion, 14 C-phorate and 14 C-carbofuran. Total amounts of 14 C-residues recovered from insecticide-treated loam soils plus oats grown in these soils were similar with DDT and oarbofuran. They were also higher than those observed with the other insecticides. While most of the 14 C-DDT residues remained in the soils, most of the 14 C-carbofuran residues were recovered from oat leaves in the form of carbofuran and 3-hydroxycarbofuran. 14 C-residues of all insecticides were more persistent in loam than in sandy soil and sand-grown oats took up more 14 C-insecticide residues than loamgrown oats. The more water-soluble insecticides, 14 C-phorate and Ccarbofuran were more mobile and were metabolized to a greater extent than insecticides of lower water solubilities. Unextractable (bound) 14 C-residues in loam soil ranged from 2.8% to 29.1% of the applied doses of 14 C-DDT and 14 C-parathion, respectively. Bound 14 C-residues were lower in the sandy soil than in the loam soil, however, plant-bound 14 C-residues were higher in oats grown in the sandy soil than in loam grown oats. Insecticide metabolites recovered from soils and plants were identified and quantitated whenever possible. The oxygen analog metabolites of the organophosphorus insecticides were most abundant in the sandy soil and in oats grown therein. Data illustrate the importance of chemical structure, water solubility and soil type in predicting the comparative environmental behaviour of pesticides. (author)

  13. Long-term bioremediation of a subsurface plume in silty soil

    International Nuclear Information System (INIS)

    Mose, D.G.; Mushrush, G.W.

    2000-01-01

    In northern Virginia, a loss from a tank farm has produced two plumes, containing about 200,000 gal of diesel fuel, jet-A fuel, and gasoline. Evidence suggests that the longest part of the contamination plume moved to its present length of 2,500 ft in less than 5 years. Since natural biodegradation would require about 2,500 years to reduce the hydrocarbon contamination to the remediation endpoints, other methods have been considered. Excavation of the plumes would take an estimated 5 years. However, the tank farm is surrounded by commercial buildings and expensive homes, and many of these buildings would have to be removed to reach the plumes. Enhanced natural bioremediation would require about 200 years at a start-up cost of about $1 million dollars and recurring costs of approximately $500,000/year. Infiltration galleries and enhanced subsurface permeability could reduce the remediation time to as little as 20 years

  14. An automated microinfiltrometer to measure small-scale soil water infiltration properties

    Directory of Open Access Journals (Sweden)

    Gordon Dennis C.

    2014-09-01

    Full Text Available We developed an automated miniature constant-head tension infiltrometer that measures very small infiltration rates at millimetre resolution with minimal demands on the operator. The infiltrometer is made of 2.9 mm internal radius glass tube, with an integrated bubbling tower to maintain constant negative head and a porous mesh tip to avoid air-entry. In the bubbling tower, bubble formation and release changes the electrical resistance between two electrodes at the air-inlet. Tests were conducted on repacked sieved sands, sandy loam soil and clay loam soil, packed to a soil bulk density ρd of 1200 kg m-3 or 1400 kg m-3 and tested either air-dried or at a water potential ψ of -50 kPa. The change in water volume in the infiltrometer had a linear relationship with the number of bubbles, allowing bubble rate to be converted to infiltration rate. Sorptivity measured with the infiltrometer was similar between replicates and showed expected differences from soil texture and ρd, varying from 0.15 ± 0.01 (s.e. mm s-1/2 for 1400 kg m-3 clay loam at ψ = -50 kPa to 0.65 ± 0.06 mm s-1/2 for 1200 kg m-3 air dry sandy loam soil. An array of infiltrometers is currently being developed so many measurements can be taken simultaneously.

  15. La gestión social del agua en las organizaciones de usuarios/as/as del territorio de la sub cuenca del río Pisque

    OpenAIRE

    Cachipuendo Ulcuango, Charles Jim

    2013-01-01

    The micro watershed of the Pisque river is located north of the Pichincha Province at 70 km from Quito, Ecuador’s capital. The natural flow of the river irrigates two cantones Cayambe and Pedro Moncayo. Based on the altitude and environmental conditions three specific zones can be differentiated, high, medium and low. These two cantons have an altitude between 2600–3000 above sea level and have mainly clayey, clayey-loam, sandy and sandy-loam soils. The region’s main crops are ...

  16. ALLTEM Multi-Axis Electromagnetic Induction System Demonstration and Validation

    Science.gov (United States)

    2011-11-17

    8217/ SAM /’/ 0. 100 -~==;;;:~~~;~~~~~~i~~~~~~~§~~~~~~~~~~~~~ SPM /’/ O.OSO+ SPM 1) ~ 9PM /’/ ~ O.OOO -~ lOAM "’ "’ 0 > "’ "’ 0 > .O . OSO ...1) ~ 9PM /V ~ o.ooo -IP’ lOAM .o . oso -r-------------------------------------t,.~IO!P~M_l/V~]J .O. l00 -~---------------------------------------1

  17. Using 15N in studies on the uptake of mineral and organic nitrogen by plants

    International Nuclear Information System (INIS)

    Mitovska, R.

    1983-01-01

    Modelled microplot field experiments at the Central Experimental Station of the All-Union Institute of Fertilizers and Agrochemistry in Moscow were used to study the uptake of nitrogen ( 15 N) applied together or individually with minerals or with green oats mass or in both ways. The studies were conducted on soddy podzolic, heavy loam, soddy podzolic sandy soil and leached chernozem. It was established that the soddy podzolic heavy loam had the highest natural fertility and showed greatest response to the applied N

  18. Rockmagnetic correlation between Holocene cave sediments at the mountain and loess soil deposits in Piedmont Crimea (on example of the trap cave Emine-Bair-Khosar and archaeological site Biyuk-Karasu-XIX

    Directory of Open Access Journals (Sweden)

    Kseniia BONDAR

    2014-11-01

    Full Text Available Modern soils and paleosols, loess and uncemented aeolian caves sediments are carriers of a paleoclimatic signal (Evans, Heller, 2003. The saturation degree of a layer with humus material, depending on the temperature, correlates well with magnetic susceptibility and different types of magnetization of deposits (Tang et al., 2003, Bosak&Pruner, 2011.On the base of rockmagnetic measurements of soil-containing samples, collected from sections at Biyuk-Karasu-XIX (Piedmont Crimea and Emine-Bair-Khosar Cave (lower plateau of Chatyrdag mountain massive in Crimea (Ridush et al., 2013, correlation of sediments done in the context of common climate changes in the region during Holocene.The process of sediments accumulation in the sections covers roughly the same period. The loess soil section Biyuk-Karasu-XIX contains findings of hand shaped pottery and flintstones. The section structure has characteristic features of Holocene soil formation for which received a definite chronological anchor. The section of cave deposits in the Emine-Bair-Khosar Cave was dated by radiocarbon and paleomagnetic methods (Ridush et al., 2013. For saiga bone from the depth of 2.0 m radiocarbon (14C date 10,490 +/- 170 (Ki-13063 obtained. At -1.1 m deep the paleomagnetic excursion, dated 2.8 kyr BP, was recorded (Bondar, Ridush, 2010.Sediments of both sections are horizontally-layered. They contain darker units, which color is controlled by organic material, and lighter units of loess-like loam.Section Biyuk-Karasu-XIX consists of the following lithofacial units: 1, 2 - hlb2 – meadow alkaline chernozem, where unit 1 - horizon Hegl, unit 2 - horizon Hp, Pikgl, Pkgl; 3, 4 - hlb1 - the soil has features of grey or sod-calcareous soil forming, unit 3 combines horizons He and Eh, unit 4 – illuvial horizons Ihp and Pigl; 5 - pc-bg? - silty-sandy light loam. Lithofacial units are named according to “Stratigraphic scheme of Quaternary deposits of Ukraine” (Veklich et al

  19. Effects of the herbicide glyphosate on the uptake of 239Pu and 241Am to vegetation

    International Nuclear Information System (INIS)

    Nisbet, A.F.; Shaw, S.

    1990-01-01

    Glyphosate (n-phosphonomethyl glycine) is a broad spectrum herbicide widely used in lowland agriculture, forestry and improved upland pastures. Although its metal chelating properties are well established, its interaction with radionuclides remains unknown. A pot experiment was conducted to determine the effect of soil applications of glyphosate on the uptake of 239 Pu and 241 Am to peas and carrots grown in loam, peat and sand soils. Soil-to-plant transfer factors were calculated for treated and untreated soils at harvest. The most marked effect was an increase in 241 Am uptake to crops grown in loam soil. Supplementary laboratory batch experiments were conducted by shaking radiolabelled soil and its associated soil solution with glyphosate. The activity concentration of 241 Am increased ten fold in the liquid phase of loam soils treated with glyphosate. It is postulated that this 241 Am desorption could have been mediated by the formation of a stable Am-glyphosate complex which was subsequently more available for crop uptake than Am alone. (author)

  20. The behavior and bioactivity of imazaquin in soils

    International Nuclear Information System (INIS)

    McKinnon, E.J.

    1989-01-01

    Laboratory studies were conducted to determine the adsorption and relative mobility of 14 C-labelled imazaquin (2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imadazol-2-yl]-3-quinolinecarboxylic acid) and 14 C labelled metolachlor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide) on Norfolk sand loan (Typic Paleudult), Rion sandy clay loam (Typic Hapludult), Cape Fear sandy clay loam (Typic Umbraquult) and Webster clay loam (Typic Hapluquoll). Imazaquin was more mobile than metolachlor on all four soils. Soils high in humic matter content retained between 45 and 48% of the applied imazaquin and 93 and 97% of the applied metolachlor. The relative order of mobility of imazaquin in the soils was Rion = Norfolk > Cape Fear = Webster. The order for metolachlor in the soils was Rion > Norfolk > Cape Fear > Webster. Adsorption of imazaquin and metolachlor was inversely related to their mobility in the soil columns. Adsorption of imazaquin increased as the suspension pH decreased

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

    Science.gov (United States)

    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

  2. Using /sup 15/N in studies on the uptake of mineral and organic nitrogen by plants

    Energy Technology Data Exchange (ETDEWEB)

    Mitovska, R. (Akademiya na Selskostopanskite Nauki, Sofia (Bulgaria). Inst. po Pochvoznanie)

    1983-01-01

    Modelled microplot field experiments at the Central Experimental Station of the All-Union Institute of Fertilizers and Agrochemistry in Moscow were used to study the uptake of nitrogen (/sup 15/N) applied together or individually with minerals or with green oats mass or in both ways. The studies were conducted on soddy podzolic, heavy loam, soddy podzolic sandy soil and leached chernozem. It was established that the soddy podzolic heavy loam had the highest natural fertility and showed greatest response to the applied N.

  3. Advance of Wetting Front in Silt Loam Soil

    Directory of Open Access Journals (Sweden)

    Mohamed Mahmood

    2013-04-01

    Full Text Available Under drip irrigation , the plant's root is concentrated inside the wetted bulb (region. Thus, the development of these roots and the plant production are greatly affected by the wetting pattern. Therefore, the wetting pattern of soil under drip irrigation must be taken into consideration in the design of drip irrigation system for both single dripping source or multi-overlapping wetting patterns of dripping water sources.2The aim of this study is to evaluate the effect of initial water content of the soil and spacing between two adjacent dripping sources with different flow rate on the movement of the wetting front.This study included 16 tests for monitoring the advancement of the wetting front with time during and after the water application phase. The water advance and water distribution measurement are carried out for two cases of the soil profile: for the first case with initial volumetric water content of 4.08% and for the second case with initial volumetric water content of 12.24%. Two spacing between the emitter were tested 25cm and 50 cm using application flow rates of 0.606, 1.212, 1.818, and 2.424 cm3 /min/cm to show the combined effect of spacing and flow rate on the performance of two adjacent emitter.The study proposed a method for determining the spacing between the two emitting sources , the water application rate and watering time. The proposed method depends on a wetted zone whose depth is equal to the root zone depth with a values equals to the maximum vertical advance of the wetting front underneath the drip line at time when this depth is equal to the depth of wetting at mid­point between the drip line. the study revealed that both the vertical water advance in soil underneath the emitter and the horizontal advance of the wetting front is larger than those in the case of single emitter.Furthermore, the vertical water advance increases with the decrease spacing between the two drip lines. Also, the horizontal advance of the wetting front is not affected by varying this spacing for both studied cases of initial water content.

  4. A Preliminary Design of a Calibration Chamber for Evaluating the Stability of Unsaturated Soil Slope

    Science.gov (United States)

    Hsu, H.-H.

    2012-04-01

    The unsaturated soil slopes, which have ground water tables and are easily failure caused by heavy rainfalls, are widely distributed in the arid and semi-arid areas. For analyzing the stability of slope, in situ tests are the direct methods to obtain the test site characteristics. The cone penetration test (CPT) is a popular in situ test method. Some of the CPT empirical equations established from calibration chamber tests. The CPT performed in calibration chamber was commonly used clean quartz sand as testing material in the past. The silty sand is observed in many actual slopes. Because silty sand is relatively compressible than quartz sand, it is not suitable to apply the correlations between soil properties and CPT results built from quartz sand to silty sand. The experience on CPT calibration in silty sand has been limited. CPT calibration tests were mostly performed in dry or saturated soils. The condition around cone tip during penetration is assumed to be fully drained or fully undrained, yet it was observed to be partially drained for unsaturated soils. Because of the suction matrix has a great effect on the characteristics of unsaturated soils, they are much sensitive to the water content than saturated soils. The design of an unsaturated calibration chamber is in progress. The air pressure is supplied from the top plate and the pore water pressure is provided through the high air entry value ceramic disks located at the bottom plate of chamber cell. To boost and uniform distribute the unsaturated effect, four perforated burettes are installed onto the ceramic disks and stretch upwards to the midheight of specimen. This paper describes design concepts, illustrates this unsaturated calibration chamber, and presents the preliminary test results.

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

    Science.gov (United States)

    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

  6. 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.

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Fugen Dou

    Full Text Available 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.

  8. Transport of Pathogen Surrogates in Soil Treatment Units: Numerical Modeling

    Directory of Open Access Journals (Sweden)

    Ivan Morales

    2014-04-01

    Full Text Available Segmented mesocosms (n = 3 packed with sand, sandy loam or clay loam soil were used to determine the effect of soil texture and depth on transport of two septic tank effluent (STE-borne microbial pathogen surrogates—green fluorescent protein-labeled E. coli (GFPE and MS-2 coliphage—in soil treatment units. HYDRUS 2D/3D software was used to model the transport of these microbes from the infiltrative surface. Mesocosms were spiked with GFPE and MS-2 coliphage at 105 cfu/mL STE and 105–106 pfu/mL STE, respectively. In all soils, removal rates were >99.99% at 25 cm. The transport simulation compared (1 optimization; and (2 trial-and-error modeling approaches. Only slight differences between the transport parameters were observed between these approaches. Treating both the die-off rates and attachment/detachment rates as variables resulted in an overall better model fit, particularly for the tailing phase of the experiments. Independent of the fitting procedure, attachment rates computed by the model were higher in sandy and sandy loam soils than clay, which was attributed to unsaturated flow conditions at lower water content in the coarser-textured soils. Early breakthrough of the bacteria and virus indicated the presence of preferential flow in the system in the structured clay loam soil, resulting in faster movement of water and microbes through the soil relative to a conservative tracer (bromide.

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

    Science.gov (United States)

    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.

  10. Control of Eolian soil erosion from waste site surface barriers

    International Nuclear Information System (INIS)

    Ligotke, M.W.

    1994-11-01

    Physical models were tested in a wind tunnel to determine optimum surface-ravel admixtures for protecting silt-loam soil from erosion by, wind and saltating, sand stresses. The tests were performed to support the development of a natural-material surface barrier for and waste sites. Plans call for a 2-m deep silt-loam soil reservoir to retain infiltrating water from rainfall and snowmelt. The objective of the study was to develop a gravel admixture that would produce an erosion-resistant surface layer during, periods of extended dry climatic stress. Thus, tests were performed using simulated surfaces representing dry, unvegetated conditions present just after construction, after a wildfire, or during an extended drought. Surfaces were prepared using silt-loam soil mixed with various grades of sand and Travel. Wind-induced surface shear stresses were controlled over the test surfaces, as were saltating, sand mass flow rates and intensities. Tests were performed at wind speeds that approximated and exceeded local 100-year peak gust intensities. Surface armors produced by pea gravel admixtures were shown to provide the best protection from wind and saltating sand stresses. Compared with unprotected silt-loam surfaces, armored surfaces reduced erosion rates by more than 96%. Based in part on wind tunnel results, a pea gravel admixture of 15% will be added to the top 1 in of soil in a prototype barrier under construction in 1994. Field tests are planned at the prototype site to provide data for comparison with wind tunnel results

  11. Effects of soil type, moisture content, redox potential and methyl bromide fumigation on Kd values of radio-selenium in soil

    International Nuclear Information System (INIS)

    Ashworth, D.J.; Moore, J.; Shaw, G.

    2008-01-01

    Understanding the processes that determine the solid-liquid partitioning (K d value) of Se is of fundamental importance in assessing the risk associated with the disposal of radio-selenium-containing waste. Using a mini-column (rather than batch) approach, K d values for 75 Se were determined over time in relation to soil moisture content (field capacity or saturated), redox potential and methyl bromide fumigation (used to disrupt the soil microbial population) in three contrasting soil types: clay loam, organic and sandy loam. The K d values were generally in the range 50-500 L kg -1 , with mean soil K d increasing with increasing organic matter content. Saturation with water lowered the measured redox potentials in the soils. However, only in the sandy loam soil did redox potential become negative, and this led to an increase in 75 Se K d value in this soil. Comparison of the data with the Eh-pH stability diagram for Se suggested that such strong reduction may have been consistent with the formation of the insoluble Se species, selenide. These findings, coupled with the fact that methyl bromide fumigation had no discernible effect on 75 Se K d value in the sandy loam soil, suggest that geochemical, rather than microbial, processes controlled 75 Se partitioning. The inter-relations between soil moisture content, redox potential and Se speciation should be considered in the modelling and assessment of radioactive Se fate and transport in the environment

  12. Taaskasutusest armastusega / Tiiu Suvi

    Index Scriptorium Estoniae

    Suvi, Tiiu

    2006-01-01

    Tuuliki Peili loomingulistest rõivastest, mis kannavad silti "Humana Disain" ning on valmistatud peamiselt second-hand materjalist ja Tallinna Taaskasutuskeskuse tekstiilikojast ning selle meistri Pille Kelleri tegemistest

  13. 76 FR 22922 - JLG Industries, Inc., Access Division, A Subsidiary of Oshkosh Corporation, Hagerstown, MD...

    Science.gov (United States)

    2011-04-25

    ... access equipment. The negative determination was based on the findings that the subject firm worker group... as required by Section 222 of the Trade Act of 1974, as amended. Further, the group eligibility... different times for different employees to maintain some semblance of a work force.'' The Department has...

  14. Archaeological Investigations in the Gainesville Lake Area of the Tennessee-Tombigbee Waterway. Volume I. The Gainesville Lake Area Excavations.

    Science.gov (United States)

    1981-01-01

    which that record is transposed to the archaeologist’s notes is it preserved for study either by the collector himself or by other students. A good...Late Archaic or Possible prepared clay hearth Leoel I Fired Clay Loam Broken Pumpkin Concentrat ion Creek Phase 2 44 ’NIIOU Bowl 3.bx3.bx2.5 Dark...LeoL 2 Fired c.loy Loam Clay. Charcoal Broken Pumpkin "ncool rat Lo Creek Phu.e S 1o0U.NOO ,traignt I.7.2.4.4.u Mdtum ’ark Brown Ceramics. Llthlcs

  15. Effect of Adding Sugarcane Bagasse and Filter Cake and Wetting and Drying Cycles on Pre-Compaction Stress of Soil

    Directory of Open Access Journals (Sweden)

    Z Nemati

    2018-03-01

    Full Text Available Introduction The compaction of soil by agricultural equipment has become a matter of increasing concern because compaction of arable lands may reduce crop growth and yield, and it also has environmental impacts. In nature, soils could be compacted due to its own weights, external loads and internal forces as a result of wetting and drying processes. Soil compaction in sugarcane fields usually occurs due to mechanized harvesting operations by using heavy machinery in wet soils. Adding plant residues to the soil can improve soil structure. To improve soil physical quality of sugarcane fields, it might be suggested to add the bagasse and filter cake, which are the by-products of the sugar industry, to the soils. When a soil has been compacted by field traffic or has settled owing to natural forces, a threshold stress is believed to exist such that loadings inducing lower than the threshold cause little additional compaction, whilst loadings inducing greater stresses than the threshold cause much additional compaction. This threshold is called pre-compaction stress (σpc. The σpc is considered as an index of soil compactibility, the maximum pressure a soil has experienced in the past (i.e. soil management history, and the maximum major principal stress a soil can resist without major plastic deformation and compaction. Therefore, the main objective of this study was to investigate the effects of wetting and drying cycles, soil water content, residues type and percent on stress at compaction threshold (σpc. Materials and Methods In this research, the effect of adding sugarcane residues (i.e., bagasse and filter cake with two different rates (1 and 2% on pre-compaction stress (σpc in a silty clay loam soil which was prepared at two relative water contents of 0.9PL (PL= plastic limit, moist and 1.1PL (wet with or without wetting and drying cycles. This study was conducted using a factorial experiment in a completely randomized design with three

  16. Slope and Land Use Changing Effects on Soil Properties and Magnetic Susceptibility in Hilly Lands, Yasouj Region

    Directory of Open Access Journals (Sweden)

    rouhollaah vafaeezadeh

    2017-02-01

    Full Text Available Introduction: Land use changes are the most reasons which affect natural ecosystem protection. Forest soils have high organic matter and suitable structure, but their land use management change usually affects soil properties and decreases soil quality. There are several outcomes of such land use changes and intensification: accelerated soil erosion and decline of soil nutrient conditions, change of hydrological regimes and sedimentation and loss of primary forests and their biodiversity. Establishing effects of land use and land cover changes on soil properties have implications for devising management strategies for sustainable use. Forest land use change in Yasouj caused soil losses and decreased soil quality. The objectives of this study were to assess some soil physical and chemical properties and soil magnetic susceptibility changes in different land uses and slope position. Materials and Methods: Soil samples were taken from natural forest, degraded forest and dryland farm from different slops (0-10, 10-20 and 20-30 percent in sout east of Yasouj. They were from 0–10 cm depth in a completely randomized design with five replications. Soil moisture and temperature regimes in the study area are xeric and mesic, respectively. Particle size distribution was determined by the hydrometer method and soil organic matter, CaCO3 equivalent and bulk density was determined using standard procedures described in Methods of Soil Analysis book. Magnetic susceptibility was measured at low and high frequency of 0.46 kHz (χlf and 4.6 kHz (χHf respectively with a Bartington MS2D meter using approximately 20 g of soil held in a four-dram clear plastic vial. Frequency dependent susceptibility (χfd is expressed as the difference between the high and the low frequency measurements as a percentage of χ at low frequency. Results and Discussion: Soil texture was affected by land use change from silty clay loam in forest to silty loam in dry land farm

  17. Identification of Soil Properties and Organophosphate Residues From Agricultural Land in Wanasari Sub-District, Brebes, Indonesia

    Science.gov (United States)

    Joko, Tri; Anggoro, Sutrisno; Sunoko, Henna Rya; Rachmawati, Savitri

    2018-02-01

    Organophosphates have been used to eradicate pests and prevent losses from harvest failures caused by pest attack. It is undeniable that the organophosphate persist in soil. This study aims to identify the organophosphate residue and soil properties include pH, soil texture, and permeability. The soil samples were taken from cropland in 10 villages, Wanasari sub-district, Brebes, Indonesia. Organophosphate residue determined by gas chromatography using Flame Photometric Detector. Soil texture was determined by soil texture triangle from NRCS USDA, and the permeability value was determined by falling head method. The mean value of chlorpyrifos, profenofos, diazinon were 0.0078; 0.0388; 0.2271 mg/l respectively. The soil texture varies from clay, silt clay, loam, silt loam, and silt clay loam with permeability value at 10-7 with the soil pH value between 6.4 - 8.1. The results showed that organophosphate residues found in the soil and its potential affect the soil fertility decline. We recommend to conduct routine soil quality analysis to prevent soil damage in the agricultural environment.

  18. Residues of Avermectin B1a in rotational crops and soils following soil treatment with [14C]Avermectin B1a

    International Nuclear Information System (INIS)

    Moye, H.A.; Malagodi, M.H.; Yoh, H.; Leibee, G.L.; Ku, C.C.; Wislocki, P.G.

    1987-01-01

    [ 14 C]Avermectin B 1 a was applied twelve times to muck and sandy loam soils and three times to sandy soil at 0.025-0.030 lb/acre per application. These applications simulated the intended use of avermectin B 1 a on celery, vegetables, and cotton, respectively. Following three aging periods in each soil type, sorghum, lettuce, and carrot or turnip seeds were planted and harvested at one-fourth, half, and full size. Analysis of these crops by oxidative combustion demonstrated that crops grown in muck, sandy loam, and sandy soils contained radiolabeled residues ranging from below the limit of quantitation (BLQ) to 7.4 μg/kg of avermectin B 1 a equivalents, BLQ to 11.6 μg/kg, and BLQ to 3.54 μg/kg, respectively. There was a general trend of decreasing residue concentrations with increasing preharvest intervals in crops grown in all soils. The radioactivity present in muck and sandy loam soils disappeared with half-lives ranging from 103 to 267 days and from 102 to 132 days, respectively

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

    International Nuclear Information System (INIS)

    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 160x60 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. - Spatial variation determines risk assessment for pesticides in soil

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bending, Gary D. [Warwick HRI, University of Warwick, Wellesbourne, Warwick CV35 9EF (United Kingdom)]. E-mail: gary.bending@warwick.ac.uk; Lincoln, Suzanne D. [Warwick HRI, University of Warwick, Wellesbourne, Warwick CV35 9EF (United Kingdom); Edmondson, Rodney N. [Warwick HRI, University of Warwick, Wellesbourne, Warwick CV35 9EF (United Kingdom)

    2006-01-15

    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 160x60 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. - Spatial variation determines risk assessment for pesticides in soil.

  2. Effect of Injecting Hydrogen Peroxide into Heavy Clay Loam Soil on Plant Water Status, NET CO2 Assimilation, Biomass, and Vascular Anatomy of Avocado Trees Efecto de la Inyección de Peróxido de Hidrógeno en Suelo Franco Arcilloso Pesado, sobre el Estado Hídrico, Asimilación Neta de CO2, Biomasa y Anatomía Vascular de Paltos

    Directory of Open Access Journals (Sweden)

    Pilar M Gil M

    2009-03-01

    Full Text Available In Chile, avocado (Persea americana Mill. orchards are often located in poorly drained, low-oxygen soils, situation which limits fruit production and quality. The objective of this study was to evaluate the effect of injecting soil with hydrogen peroxide (H2O2 as a source of molecular oxygen, on plant water status, net CO2 assimilation, biomass and anatomy of avocado trees set in clay loam soil with water content maintained at field capacity. Three-year-old ‘Hass’ avocado trees were planted outdoors in containers filled with heavy loam clay soil with moisture content sustained at field capacity. Plants were divided into two treatments, (a H2O2 injected into the soil through subsurface drip irrigation and (b soil with no H2O2 added (control. Stem and root vascular anatomical characteristics were determined for plants in each treatment in addition to physical soil characteristics, net CO2 assimilation (A, transpiration (T, stomatal conductance (gs, stem water potential (SWP, shoot and root biomass, water use efficiency (plant biomass per water applied [WUEb]. Injecting H2O2 into the soil significantly increased the biomass of the aerial portions of the plant and WUEb, but had no significant effect on measured A, T, gs, or SWP. Xylem vessel diameter and xylem/phloem ratio tended to be greater for trees in soil injected with H2O2 than for controls. The increased biomass of the aerial portions of plants in treated soil indicates that injecting H2O2 into heavy loam clay soils may be a useful management tool in poorly aerated soil.En Chile, los huertos de palto (Persea americana Mill. se ubican comúnmente en suelos pobremente drenados con bajo contenido de oxígeno, lo que limita producción y calidad de fruta. El objetivo de este estudio fue evaluar el efecto de la inyección de peróxido de hidrógeno (H2O2 al suelo como fuente de O2, sobre el estado hídrico, asimilación de CO2, biomasa y anatomía de paltos en suelo franco arcilloso con

  3. Adsorption-desorption characteristics of Ni, Zn and Pb in soils of a landfill environment in Metro Manila, Philippines

    International Nuclear Information System (INIS)

    Castañeda, Soledad S.; Cuarto, Christina D.; David, Carlos Primo C.

    2015-01-01

    This study investigated the sorption-desorption characteristics of Ni, Zn, and Pb on two soil types in the environment of a municipal waste disposal facility. Batch experiments were carried out in ambient temperature and in unadjusted and close to soil field pH conditions. The kinetics of of adsorption fitted a pseudo second-order model. Rate constants were calculated and an empirical model for predicting adsorption of metal ions at a given time was derived from these constants. The equilibrium sorption capacities for the heavy metals in the clay and sandy loam soils were estimated using the Linear, Freundlich, and Langmuir isotherm models. The sorption process of Ni, Pb, and Zn in both soils generally fitted well with the Freundlich isotherm model at moderate to high initial concentration range of the metals. The Langmuir isotherm was applicable to the adsorption of Ni and Zn only. The adsorption capacity of the clay soil for the metals followed the order Zn > Pb > Ni. In the sandy loam soil, the adsorption capacity for the metals under the same conditions followed the order Pb > Zn > Ni. The adsorption capacities for the metals were in order of 1mg/g in both the landfill clay soil and the Lukutan River sandy loam soil, with slightly higher values for the clay soil. Desorption was minimal, less than 1% in the clay soil and about 2% in the sandy loam soil. Sorption reversibility tests showed that the retention of the metals in both soils follows the order Ni> Pb> Zn. (author)

  4. Within- and trans-generational plasticity affects the opportunity for selection in barbed goatgrass (Aegilops triuncialis).

    Science.gov (United States)

    Espeland, Erin K; Rice, Kevin J

    2012-12-01

    Environments are composed of selective agents, and environments may also modify the efficacy of these agents. Environments affect the rate of maximum evolutionary change by influencing variation in relative fitness (i.e., the opportunity for selection, or I). Within- and transgenerational plastic environmental responses may affect I, speeding or slowing processes of local adaptation. • We determined whether environmental factors affected the opportunity for selection (I) in Aegilops triuncialis (barbed goatgrass) by measuring I as a within- and transgenerational plastic response to two maternal glasshouse environments (serpentine/dry and loam/moist). We also determined whether this species' two most common genetic lineages (determined by DNA microsatellite length polymorphism) varied in response to glasshouse treatments. • Opportunity for selection was less for plants grown in the dry serpentine environment than for plants grown in the moist loam environment. This response varied between genetic lineages. The east lineage exhibited a within-generation response to the dry serpentine environment. For both seed mass and average seed weight in this lineage, the opportunity for selection was lower in dry serpentine than in moist loam. The west lineage had a transgenerational response to the dry serpentine such that the opportunity for selection for seed number and seed mass was lower for plants produced by mothers grown in dry serpentine than for plants produced by mothers in moist loam. • Phenotypic variation in relative fitness is constrained by the dry serpentine environment, which leads to lower evolvability in this environment. Within- and transgenerational effects of the environment may slow local adaptation to serpentine soils.

  5. A discrete element model for soil-sweep interaction in three different soils

    DEFF Research Database (Denmark)

    Chen, Y; Munkholm, Lars Juhl; Nyord, Tavs

    2013-01-01

    . To serve the model development, the sweep was tested in three different soils (coarse sand, loamy sand, and sandy loam). In the tests, soil cutting forces (draught and vertical forces) and soil disturbance characteristics (soil cross-section disturbance and surface deformation) resulting from the sweep...... were measured. The measured draught and vertical forces were used in calibrations of the most sensitive model parameter, particle stiffness. The calibrated particle stiffness was 0.75 × 103 N m−1 for the coarse sand, 2.75 × 103 N m−1 for the loamy sand, and 6 × 103 N m−1 for the sandy loam...

  6. Intervalo hídrico óptimo en suelos argiudoles plantados con Eucalyptus dunnii Maiden Least limiting water range in argiudoll soils under eucalyptus dunnii maiden

    Directory of Open Access Journals (Sweden)

    Francisco Damiano

    2011-07-01

    of soil moisture values falling outside the LLWR (p out was statistically evaluated using the PROC CATMOD model. LLWR increased from 0.009 cm³ cm-3 in silty clay Bt horizons to 0.207 cm3 cm-3 in silty loam C horizons. The p out was negatively related to LLWR (R² = 0.83***. The slope of the fitted model (b1 = - 30.5475 was not altered by climatic conditions, but its intercept varied from dry (b o = 5.0083 to wet (b o = 3.5207 years. From this empirical-fundamental model, it can be concluded that LLWR is a suitable index to indicate the best soil physical conditions for the growth of eucalyptus plantations.

  7. Numerical Evaluation and Optimization of Multiple Hydraulically Fractured Parameters Using a Flow-Stress-Damage Coupled Approach

    Directory of Open Access Journals (Sweden)

    Yu Wang

    2016-04-01

    Full Text Available Multiple-factor analysis and optimization play a critical role in the the ability to maximizethe stimulated reservoir volume (SRV and the success of economic shale gas production. In this paper, taking the typical continental naturally fractured silty laminae shale in China as anexample, response surface methodology (RSM was employed to optimize multiple hydraulic fracturing parameters to maximize the stimulated area in combination with numerical modeling based on the coupled flow-stress-damage (FSD approach. This paper demonstrates hydraulic fracturing effectiveness by defining two indicesnamelythe stimulated reservoir area (SRA and stimulated silty laminae area (SLA. Seven uncertain parameters, such as laminae thickness, spacing, dip angle, cohesion, internal friction angle (IFA, in situ stress difference (SD, and an operational parameter-injection rate (IR with a reasonable range based on silty Laminae Shale, Southeastern Ordos Basin, are used to fit a response of SRA and SLA as the objective function, and finally identity the optimum design under the parameters based on simultaneously maximizingSRA and SLA. In addition, asensitivity analysis of the influential factors is conducted for SRA and SLA. The aim of the study is to improve the artificial ability to control the fracturing network by means of multi-parameteroptimization. This work promises to provide insights into the effective exploitation of unconventional shale gas reservoirs via optimization of the fracturing design for continental shale, Southeastern Ordos Basin, China.

  8. Centrifuge Modelling of Two Civil-Environmental Problems

    National Research Council Canada - National Science Library

    Goodings, Deborah

    2001-01-01

    Research Problem 1: Frost heave and thaw induced settlement in silt and silty clay developing over a year have been modelled correctly using a geotechnical centrifuge with tests requiring less than a day...

  9. Fate of diuron and terbuthylazine in soils amended with two-phase olive oil mill waste.

    Science.gov (United States)

    Cabrera, A; Cox, Lucia; Velarde, P; Koskinen, William C; Cornejo, Juan

    2007-06-13

    The addition of organic amendments to soil increases soil organic matter content and stimulates soil microbial activity. Thus, processes affecting herbicide fate in the soil should be affected. The objective of this work was to investigate the effect of olive oil production industry organic waste (alperujo) on soil sorption-desorption, degradation, and leaching of diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] and terbuthylazine [N2-tert-butyl-6-chloro-N4-ethyl-1,3,5-triazine-2,4-diamine], two herbicides widely used in olive crops. The soils used in this study were a sandy soil and a silty clay soil from two different olive groves. The sandy soil was amended in the laboratory with fresh (uncomposted) alperujo at the rate of 10% w/w, and the silty clay soil was amended in the field with fresh alperujo at the rate of 256 kg per tree during 4 years and in the laboratory with fresh or composted alperujo. Sorption of both herbicides increased in laboratory-amended soils as compared to unamended or field-amended soils, and this process was less reversible in laboratory-amended soils, except for diuron in amended sandy soil. Addition of alperujo to soils increased half-lives of the herbicides in most of the soils. Diuron and terbuthylazine leached through unamended sandy soil, but no herbicide was detected in laboratory-amended soil. Diuron did not leach through amended or unamended silty clay soil, whereas small amounts of terbuthylazine were detected in leachates from unamended soil. Despite their higher sorption capacity, greater amounts of terbuthylazine were found in the leachates from amended silty clay soils. The amounts of dissolved organic matter from alperujo and the degree of humification can affect sorption, degradation, and leaching of these two classes of herbicides in soils. It appears that adding alperujo to soil would not have adverse impacts on the behavior of herbicides in olive production.

  10. Preliminary laboratory assessments of a lightweight geocomposite material for embankment fill application

    Directory of Open Access Journals (Sweden)

    Felix Okonta

    2015-03-01

    Full Text Available The cost of retaining structures used for the lateral support of roadside embankments can be significantly reduced through the use of lightly cemented mixtures of expanded polystyrene (EPS beads and backfill soils as lightweight roadside embankment material. Four grades of residually derived sandy soils were mixed with EPS beads and the geocomposites were stabilised with 3% cement content, compacted and cured. The textural properties and shear strength parameters of dry and soaked specimens of the cemented geocomposites were determined by direct shear tests. The shear parameters and slope stability charts were used to simulate the slope of typical road embankments. The settlement potentials at different applied normal stresses were also determined. Inclusion of EPS reduced the dry density of the residual soils from an average value of 1790 kg/m3 to 1335 kg/m3. The maximum friction coefficient, tan ᴓ′, mobilised by the geocomposite specimens decreased with an increase in the soil fines content (>0.425 mm. The difference in tan ᴓ′ between the stabilised geocomposites and the natural soil was also dependent on the fines content. For an embankment height of 20 m, slope angles of 38° and 62° were determined for fine sand geocomposites in fully saturated drainage and drained conditions, respectively. Lower slope angles were determined for geocomposites made from silty, coarse and gravelly sands. A limiting embankment height of 50 m was determined for the four geocomposites. Rainfall-induced settlement of geocomposites was dependent on pre-inundation stiffness; for the range of applied stress up to 200 kPa, the settlement exhibited by the fine and silty sand geocomposites was lower than that for the coarse and gravelly sand geocomposites. Fine and silty sands make poor materials for slope embankments because of their poor hydraulic conductivity; however, fine and silty sand geocomposites have a good conductivity and friction angle to support

  11. Aplicações de misturas solo-"grits" em estradas florestais: resistência mecânica via CBR Application of soil-grits mixtures in forest roads: mechanical strength via CBR test

    Directory of Open Access Journals (Sweden)

    Reginaldo Sérgio Pereira

    2006-08-01

    Full Text Available Analisaram-se as potencialidades de emprego do resíduo sólido industrial "grits", oriundo da indústria de celulose, como agente estabilizante de dois solos da Zona da Mata Norte de Minas Gerais, Brasil, para fins de emprego em estradas florestais. Os solos estudados englobaram um residual maduro, de textura argilo-areno-siltosa, e um residual jovem, de textura areno-silto-argilosa. Para tanto, prepararam-se misturas envolvendo solos e o resíduo nos quantitativos de 4, 8, 12, 16, 20, 24 e 28% em relação às massas de solo seco. Fez-se uso do ensaio CBR para avaliar as características de resistência e expansão das misturas. A avaliação dos resultados do estudo permite concluir que o resíduo "grits" apresentou potencial significativo como estabilizante dos solos, observando-se que: (i a adição de "grits" aos solos foi responsável por ganhos nas suas resistências mecânicas, obtendo-se melhores resultados com o solo de textura areno-silto-argilosa; (ii com relação à expansão medida no ensaio CBR, observaram-se pequenos acréscimos para o solo de textura argilo-areno-siltosa e decréscimos para o solo de textura areno-silto-argilosa, com aumentos no teor de "grits"; e (iii as misturas solo-"grits" não responderam bem ao aumento da energia de compactação, quanto aos parâmetros CBR e expansãoCBR.This paper is directed to forest road engineering applications, and address the potentialities of using an industrial solid waste from the cellulose industry, named grits, in the stabilization process of two soils from Zona da Mata Norte of Minas Gerais States, Brazil. Soil types tested comprised a mature residual silty-sandy-clay and a young residual clayey-silty-sand. Soil-grits mixtures were prepared at 4, 8, 12, 16, 20, 24 and 28 % stabilizer contents referred to soil dry masses. Mechanical strength and swelling parameters were determined by CBR (California Bearing Ratio tests. The laboratory testing program data supported that

  12. Effects of Plant Residues in Two Types of Soil Texture on Soil characteristics and corn (Zea mays L. NS640 Yield in a Reduced -Tillage cropping System

    Directory of Open Access Journals (Sweden)

    E Hesami

    2018-05-01

    Full Text Available Introduction The impact of agronomy on the subsequent product in rotational cropping systems depends on factors such as plant type, duration of crop growth, soil moisture content, tillage type, irrigation method, the amount of nitrogen fertilizer, quantity and quality of returned crop residues to the soil. Prior cultivated crops improve the next crop yield by causing different conditions (nitrogen availability, organic matter and volume of available water in soil. This study was conducted due to importance of corn cultivation in Khuzestan and necessity of increasing the soil organic matter, moisture conservation and in the other hand the lack of sufficient information about the relationship between soil texture, type of preparatory crop in low-tillage condition and some soil characteristics and corn growth habits. The purpose of this experiment was to evaluate the effect of residue of preparatory crops in low plowing condition in two soil types on corn yield and some soil characteristics. Materials and Methods This experiment was carried out at Shooshtar city located in Khuzestan province. An experiment was performed by combined analysis in randomized complete block design in two fields and in two consecutive years with four replications. Two kinds of soil texture including: clay loam and clay sand. Five preparatory crops including: broad bean, wheat, canola, cabbage and fallow as control assigned as sub plots. SAS Ver. 9.1 statistical software was used for analysis of variance and comparison of means. Graphs were drawn using MS Excel software. All means were compared by Duncan test at 5% probability level. Results and Discussion The soil texture and the type of preparatory crop influenced the characteristics of the soil and corn grain yield. Returning the broad bean residue into two types of soil caused the highest grain yield of corn 10128.6 and 9547.9 kgha-1, respectively. The control treatment in sandy loam texture had the lowest corn seed

  13. Growth and nutrient concentrations of maize in pressmud treated saline-sodic soils

    Directory of Open Access Journals (Sweden)

    D. Muhammad

    2009-05-01

    Full Text Available n open-air pot experiment was conducted to investigate effects of pressmud (PM on saline-sodic soil reclamation, mitigating the adverse effects of saline irrigation and increase of maize (Zea mays L. growth. Pressmud was added at the rate of 0, 5, 10 and 20 Mg ha-1 to pots containing 6.8 kg air dried surface (0-20 cm soil collected from two sites. The increasing levels of PM enhanced maize plant height, shoots and roots biomass in both soils. However, the Soil 2, with initial EC and SAR of 5.43 dS m-1 and 18.67(m mol L-11/2, respectively, produced comparatively more biomass at all PM levels than Soil 1 [silty-clay loam, EC = 6.22 dS m-1, SAR = 20.72 (m mol L- 1 1/2]. The [P] in shoots was maximum at the highest PM in both the soils but the [K] increased with PM levels in Soil 1 and decreased in Soil 2 due to the dilution effect. The Soil 1 maintained several folds more [Na] in shoots and consequently lower K:Na ratio than Soil 2. The post harvest soil pH, Na, Ca+Mg and SAR in saturation extracts decreased with increasing levels of PM as compared to control. Soil 2 released more volume of leachate as compared to Soil 1 but the leachate EC and [Na] were comparable while [Ca+Mg] were relatively higher in Soil 2. The higher removal of total salts from Soil 2 resulted in lower soil pH, EC and SAR in this soil as compared to Soil 1. The increases in crop growth with each increment of PM up to 20 Mg ha-1 in the present study proved the benefits of PM in increasing crop yields and suggested that doses higher than 20 Mg PM ha-1 could be applied to the saline-sodic soils ofthe area to get maximum possible crop yields depending on soil and water quality

  14. Mitigation of dimethazone residues in soil and runoff water from agricultural field.

    Science.gov (United States)

    Antonious, George F

    2011-01-01

    Dimethazone, also known as clomazone [2-[(2-chlorophenyl) methyl]- 4,4-dimethyl-3-isoxaolidinone] is a pre-emergent nonionic herbicide commonly used in agriculture. A field study was conducted on a silty-loam soil of 10 % slope to monitor off-site movement and persistence of dimethazone in soil under three management practices. Eighteen plots of 22 x 3.7 m each were separated using stainless steel metal borders and the soil in six plots was mixed with municipal sewage sludge (MSS) and yard waste (YW) compost (MSS+YW) at 15 t acre⁻¹ on dry weight basis, six plots were mixed with MSS at 15 t acre⁻¹, and six unamended plots (NM) were used for comparison purposes. The objectives of this investigation were to: (i) monitor the dissipation and half-life (T₁/₂) of dimethazone in soil under three management practices; (ii) determine the concentration of dimethazone residues in runoff and infiltration water following natural rainfall events; and (iii) assess the impact of soil amendments on the transport of NO₃, NH₄, and P into surface and subsurface water. Gas chromatography/mass spectrometery (GC/MS) analyses of soil extracts indicated the presence of ion fragments at m/z 125 and 204 that can be used for identification of dimethazone residues. Intitial deposits of dimethazone varied from 1.3 μg g⁻¹ dry native soil to 3.2 and 11.8 μg g⁻¹ dry soil in MSS and MSS+YW amended soil, respectively. Decline of dimethazone residues in the top 15 cm native soil and soil incorporated with amendments revealed half-life (T₁/₂) values of 18.8, 25.1, and 43.0 days in MSS+YW, MSS, and NM treatments, respectively. Addition of MSS+YW mix and MSS alone to native soil increased water infiltration, lowering surface runoff water volume and dimethazone residues in runoff following natural rainfall events.

  15. Heavy metals in summer squash fruits grown in soil amended with municipal sewage sludge.

    Science.gov (United States)

    Antonious, George F; Snyder, John C; Dennis, Sam O

    2010-02-01

    The increasing awareness of the value of vegetables and fruits in the human diet requires monitoring of heavy metals in food crops. The effects of amending soil with compost made from municipal sewage sludge (MSS) and MSS mixed with yard waste (MSS-YW) on Cd, Cr, Mo, Cu, Zn, Pb, and Ni concentrations in soil and the potential bioaccumulation of heavy metals in squash fruits at harvest were investigated. A field study was conducted in a silty-loam soil at Kentucky State University Research Farm. Eighteen plots of 22 x 3.7 m each were separated using metal borders and the soil in six plots was mixed with MSS at 15 t acre(-1), six plots were mixed with MSS-YW at 15 t acre(-1) (on dry weight basis), and six unamended plots (no-mulch) were used for comparison purposes. Plots were planted with summer squash and heavy metals were analyzed in soil and mature fruits at harvest. Analysis of heavy metals in squash fruits was conducted using inductively coupled plasma spectrometry. Zinc and Cu concentrations in soil mixed with MSS were extremely high compared to other metals. In squash fruits, concentrations of Zn were generally greater than Cu. Total squash marketable yield was greatest in MSS-YW and MSS treatments compared to no-mulch conventional soil. Concentrations of Cd and Pb in soil amended with MSS averaged 0.1 and 1.4 mg kg(-1), respectively. These levels were much lower than the limits in the U.S. guidelines for using MSS in land farming. Data revealed that maximum concentrations of Cd and Pb in squash fruits were 0.03 and 0.01 microg g(-1) dry fruit, respectively. Nickel concentration in squash fruits fluctuated among harvest dates reaching a maximum of 2.5 microg g(-1) dry fruit. However, these concentrations were far below their permissible limits in edible fruits.

  16. Cyanobacteria Inoculation Improves Soil Stability and Fertility on Different Textured Soils: Gaining Insights for Applicability in Soil Restoration

    Directory of Open Access Journals (Sweden)

    Sonia Chamizo

    2018-06-01

    Full Text Available Cyanobacteria are ubiquitous components of biocrust communities and the first colonizers of terrestrial ecosystems. They play multiple roles in the soil by fixing C and N and synthesizing exopolysaccharides, which increase soil fertility and water retention and improve soil structure and stability. Application of cyanobacteria as inoculants to promote biocrust development has been proposed as a novel biotechnological technique for restoring barren degraded areas and combating desertification processes in arid lands. However, previous to their widespread application under field conditions, research is needed to ensure the selection of the most suitable species. In this study, we inoculated two cyanobacterial species, Phormidium ambiguum (non N-fixing and Scytonema javanicum (N-fixing, on different textured soils (from silt loam to sandy, and analyzed cyanobacteria biocrust development and evolution of physicochemical soil properties for 3 months under laboratory conditions. Cyanobacteria inoculation led to biocrust formation in all soil types. Scanning electron microscope (SEM images showed contrasting structure of the biocrust induced by the two cyanobacteria. The one from P. ambiguum was characterized by thin filaments that enveloped soil particles and created a dense, entangled network, while the one from S. javanicum consisted of thicker filaments that grouped as bunches in between soil particles. Biocrust development, assessed by chlorophyll a content and crust spectral properties, was higher in S. javanicum-inoculated soils compared to P. ambiguum-inoculated soils. Either cyanobacteria inoculation did not increase soil hydrophobicity. S. javanicum promoted a higher increase in total organic C and total N content, while P. ambiguum was more effective in increasing total exopolysaccharide (EPS content and soil penetration resistance. The effects of cyanobacteria inoculation also differed among soil types and the highest improvement in soil

  17. Soil physical properties affecting soil erosion in tropical soils

    International Nuclear Information System (INIS)

    Lobo Lujan, D.

    2004-01-01

    detachment. Studies on necessary kinetic energy to detach one kilogram of sediments by raindrop impact have shown that the minimum energy is required for particles of 0.125 mm. Particles between 0.063 to 0.250 mm are the most vulnerable to detachment. This means that soils with high content of particles into vulnerable range, for example silty loam, loamy, fine sandy, and sandy loam are the most susceptible soils to detachment. Many aspects of soil behaviour in the field such as hydraulic conductivity water retention, soil crusting, soil compaction, and workability are influenced strongly by the primary particles. In tropical soils also a negative relation between structure stability and particles of silt, fine sand and very fine sand has been found, this is attributed to low cohesiveness of these particles. The ability of a structure to persist is known as its stability. There are two principal types of stability: the ability of the soil to retain its structure under the action of water, and the ability of the soil to retain its structure under the action of external mechanical stresses. (e.g. by wheels). Both types of stability are related with susceptibility to erosion

  18. Monitoring the performance of an alternative cover using caisson lysimeters

    Energy Technology Data Exchange (ETDEWEB)

    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 with 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

  19. Integrated assessment of space, time, and management-related variability of soil hydraulic properties

    Energy Technology Data Exchange (ETDEWEB)

    Es, H.M. van; Ogden, C.B.; Hill, R.L.; Schindelbeck, R.R.; Tsegaye, T.

    1999-12-01

    Computer-based models that simulate soil hydrologic processes and their impacts on crop growth and contaminant transport depend on accurate characterization of soil hydraulic properties. Soil hydraulic properties have numerous sources of variability related to spatial, temporal, and management-related processes. Soil type is considered to be the dominant source of variability, and parameterization is typically based on soil survey databases. This study evaluated the relative significance of other sources of variability: spatial and temporal at multiple scales, and management-related factors. Identical field experiments were conducted for 3 yr. at two sites in New York on clay loam and silt loam soils, and at two sites in Maryland on silt loam and sandy loam soils, all involving replicated plots with plow-till and no-till treatments. Infiltrability was determined from 2054 measurements using parameters, and Campbell's a and b parameters were determined based on water-retention data from 875 soil cores. Variance component analysis showed that differences among the sites were the most important source of variability for a (coefficient of variation, CV = 44%) and b (CV = 23%). Tillage practices were the most important source of variability for infiltrability (CV = 10%). For all properties, temporal variability was more significant than field-scale spatial variability. Temporal and tillage effects were more significant for the medium- and fine-textured soils, and correlated to initial soil water conditions. The parameterization of soil hydraulic properties solely based on soil type may not be appropriate for agricultural lands since soil-management factors are more significant. Sampling procedures should give adequate recognition to soil-management and temporal processes at significant sources of variability to avoid biased results.

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

    Science.gov (United States)

    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.

  1. Polyacrylamide+Al2(SO4)3 and polyacrylamide+CaO remove coliform bacteria and nutrients from swine wastewater

    International Nuclear Information System (INIS)

    Entry, J.A.; Phillips, Ian; Stratton, Helen; Sojka, R.E.

    2003-01-01

    Polyacrylamide mixture may be able to reduce run-off of enteric bacteria from animal wastes. - Animal wastes are a major contributor of nutrients and enteric microorganisms to surface water and ground water. Polyacrylamide (PAM) mixtures are an effective flocculent, and we hypothesized that they would reduce transport of microorganisms in flowing water. After waste water running at 60.0 l min -1 flowed over PAM+Al 2 (SO 4 ) 3 , or PAM+CaO in furrows, total coliform bacteria (TC) and fecal coliform bacteria (FC) were reduced by 30-50% at 1 and 50 m downstream of the treatments compared to the control. In a column study, PAM+Al 2 (SO 4 ) 3 , and PAM+CaO applied to sandy, sandy loam, loam, and clay soils reduced NH 4 + and ortho-P concentrations in leachate compared to the source waste water and the control. PAM+Al 2 (SO 4 ) 3 and PAM+CaO applied to sandy, sandy loam and loam soils reduced both total and ortho-P, concentrations in leachate compared to the source wastewater and control treatment. In a field study, PAM+Al 2 (SO 4 ) 3 , or PAM+CaO treatments did not consistently reduce NH 4 + , NO 3 - , ortho-P, and total P concentrations in wastewater flowing over any soil compared to inflow wastewater or the control treatment. With proper application PAM+ Al 2 (SO 4 ) 3 and PAM+CaO may be able to reduce the numbers of enteric bacteria in slowly flowing wastewater running off animal confinement areas, reducing the amount of pollutants entering surface water and groundwater

  2. Determining photon energy absorption parameters for different soil samples

    International Nuclear Information System (INIS)

    Kucuk, Nil; Cakir, Merve; Tumsavas, Zeynal

    2013-01-01

    The mass attenuation coefficients (μ s ) 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 137 Cs and 60 Co (370 kBq) radioactive point gamma sources. The measurements were made by performing transmission experiments with a 2″ x 2″ NaI(Tl) scintillation detector, which had an energy resolution of 7% at 0.662 MeV for the gamma-rays from the decay of 137 Cs. The effective atomic numbers (Z eff ) and the effective electron densities (N eff ) were determined experimentally and theoretically using the obtained μ s values for the soil samples. Furthermore, the Z eff and N eff 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. (author)

  3. Conservation of nitrate during the fallow; Conservacion del nitrogeno durante el barbecho

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez Aguilar, M.

    2004-07-01

    We study the possibility to use the waste-water from olive oil mills, or woom to reduce the leaching, of nitrate during the fallow. The blocking in time that practice the woom about the nitrogen of soil we are suggest this study. We make use of woom dilute in water and we study the influence,as soon as the contained potassium, on the nitrogen leaching of two soils, loam and silt-clay loam. The irrigation of soils with woom dilute in water from ten to forty times prior to the autumnal rains to be worth for reducing the leaching of nitrate during the fallow. (Author) 21 refs.

  4. Integral abutment bridge for Louisiana's soft and stiff soils : Tech summary.

    Science.gov (United States)

    2016-03-01

    In this project, fi eld-instrumentation, monitoring, and analyzing the design and : construction of full integral abutment bridges for Louisianas fi ne sand and silty sand : deposit and clay soil conditions were conducted. Comparison of results wa...

  5. 160-169 Characterization and Fertility Status of the Soils of Ayehu Res

    African Journals Online (AJOL)

    The soils were moderately acidic in reaction and silty clay to clay in texture. ... Application of increasing rates of P fertilizer increased both the Olsen and Bray II P consistently, while .... by the modified Bouyoucos hydrometer method.

  6. Lixiviação e inativação do metribuzin em dois tipos de solos Leaching and inactivation of metribuzin in two soil types

    Directory of Open Access Journals (Sweden)

    J. Ferreira da Silva

    1981-12-01

    Full Text Available Com o objetivo de avaliar a lixiviação e a inativação do herbicida metribuzin (4-amino-6-tertbutil-3-(metiltio-as-triazina-5-(4Hona em materiais de um solo franco-argiloso e de outro solo franco-argilo-arenoso de duas regiões de Minas Gerais, um em laboratório e outro em casa de vegetação. O solo franco-argiloso era um Latossolo Roxo, com 2,8% de matéria orgãnica e o solo franco-argilo-arenoso era um Podzólico Vermelho-Amarelo; fase terraço, em 2,17% de matéria orgânica. Em laboratório estudou-se a lixiviação do metribuzin em colunas de 5, 10 e 15 cm de altura, com 7,5 cm de diâmetro, enchidas com materiais dos solos franco-argiloso e do solo franco-argiloarenoso. Usou-se o ensaio biológico de discos de cotilédones de melancia para detectar o metribuzin no lixiviado. Em casa de vegetação, estudou-se a inativação do metribuzin com materiais dos mesmos solos utilizados para o estudo de lixiviação. Para este ensaio foram utilizadas as doses de 0, 50, 80, 110, 140, 170 e 200g do i.a./ha do produto, e em areia lavada, as doses foram de 0, 4, 6, 8, 10, 12 e 16 g do i.a./ha do metribuzin, usando o pepino como planta teste, que foi cortado rente ao solo e pesado aos 14 dias após o plantio. Informações adicionais são necessárias para explicar porque o solo franco -argiloso inativa mais o metribuzin que o solo franco-argilo-arenoso.Laboratory and greenhouse experiments were made to evaluate the leaching and the inactivation of the metribuzin in clay loam and sand clay loam soils. The clay loam soil was a dark, red latosol with 2,8% organic matter and the sand clay loam soil was a reddish-yellow podzol with 2,17% organic matter. Leaching of metribuzin was studied in the laboratory in colums of 5, 10 and 15 cm high, 7.5 cm diameter, filled with soil. Watermelon cotiledon discs were used to measure the metribuzin leached. The inactivation of metribuzin was estudied in a greenhouse using doses of 0, 50, 80, 110, 140, 170 and 200

  7. Sorção do imazapyr em solos com diferentes texturas Imazapyr sorption in soils with different textures

    Directory of Open Access Journals (Sweden)

    L.E. Firmino

    2008-06-01

    Full Text Available O conhecimento do comportamento de herbicidas no ambiente, sobretudo no solo, permite a predição de possíveis impactos do seu uso em sistemas agrícolas. Com o intuito de avaliar a sorção do herbicida imazapyr no solo, foi realizado um experimento, utilizando sorgo (Sorghum bicolor como planta bioindicadora. A sorção do imazapyr foi avaliada em areia lavada e em três solos, com as seguintes texturas: muito argilosa, franco-argilo-arenosa e areia-franca, provenientes, respectivamente, das cidades de Sete Lagoas, João Pinheiro e Rio Casca, em Minas Gerais. Foram determinados: o valor de I50 (dose que inibiu 50% no acúmulo de massa seca da planta-teste e a relação de sorção [RS = (I50 solo -I 50 areia/I50 areia]. Os valores de I50 observados foram: 29,41; 10,20 e 7,33 mg kg-1, e a relação de sorção (RS: 9,77; 2,73 e 1,68, respectivamente para os solos muito argiloso, franco-argilo-arenoso e areia franca. O herbicida imazapyr apresentou a seguinte ordem de sorção nos substratos: muito argiloso > franco-argilo-arenoso > areia-franca > areia lavada. Em solos arenosos e com baixos teores de matéria orgânica, a baixa sorção do imazapyr predispõe o produto à lixiviação no perfil do solo, podendo contaminar mananciais de águas subterrâneas.Knowledge about herbicide behavior in the environment, especially in soil, allows predicting possible impacts caused by its use in agricultural systems. An experiment using Sorghum bicolor as a bio-indicator was carried out to evaluate imazapyr sorption in soil. Sorption was evaluated in washed sand and in soils of 3 different textures: very clayed, sandy clayed loam and sandy loam, respectively from Sete Lagoas, João Pinheiro and Rio Casca - Minas Gerais. The value of I50, which inhibits 50% of dry biomass accumulation of the test-plant, and sorption relation (SR = I50 soil - I50 sand/I50 sand were determined. I50 values observed were 29.41, 10.20 and 7.33 mg kg-1 and SR values were 9

  8. Occurrence of volcanic ash in the Quaternary alluvial deposits, lower ...

    Indian Academy of Sciences (India)

    of finely laminated silty sand and gravel lenses. ... undulating upper contact following the pre-existing ... The ash material is light with its specific .... negative Eu-anomaly, area enclosed within blue line indicates compositional range of the distal ...

  9. Osnovnye zakonomernosti raspredelenija, migracii i nakoplenija radionuklidov v donnyh otlozhenijah Baltijskogo morja [The basic patterns of the distribution, migration and accumulation of radionuclides in the bottom sediment of the Baltic Sea

    Directory of Open Access Journals (Sweden)

    Grigoryev Andrey

    2011-01-01

    Full Text Available This paper focuses on the impact of certain factors on the contemporary distribution of natural (226Ra, 232Th, 40К and anthropogenic (137Cs, 60Co radionuclides in the sediments of the Baltic Sea. The results of the study suggest that the distribution of 137Cs is determined by the content of hydromica of silty-clay and clay grain-size fractions, while radiocaesium is mainly accumulated by silty fractions. The accumulation of 226Ra by bottom sediments is mainly determined by the pH geochemical barrier at the water-seafloor boundary. The accumulation of 232Th occurs mainly in clayey fractions of the sediment. The distribution and accumulation of 40K is predominantly determined by the ratio of potassium contained in hydromica minerals. Significant 60Co activity was registered only in a few samples.

  10. A case study on stratified settlement and rebound characteristics due to dewatering in Shanghai subway station.

    Science.gov (United States)

    Wang, Jianxiu; Huang, Tianrong; Sui, Dongchang

    2013-01-01

    Based on the Yishan Metro Station Project of Shanghai Metro Line number 9, a centrifugal model test was conducted to investigate the behavior of stratified settlement and rebound (SSR) of Shanghai soft clay caused by dewatering in deep subway station pit. The soil model was composed of three layers, and the dewatering process was simulated by self-invention of decompressing devise. The results indicate that SSR occurs when the decompression was carried out, and only negative rebound was found in sandy clay, but both positive and negative rebound occurred in the silty clay, and the absolute value of rebound in sandy clay was larger than in silty clay, and the mechanism of SSR was discussed with mechanical sandwich model, and it was found that the load and cohesive force of different soils was the main source of different responses when decompressed.

  11. Polyacrylamide+Al{sub 2}(SO{sub 4}){sub 3} and polyacrylamide+CaO remove coliform bacteria and nutrients from swine wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Entry, J.A.; Phillips, Ian; Stratton, Helen; Sojka, R.E

    2003-03-01

    Polyacrylamide mixture may be able to reduce run-off of enteric bacteria from animal wastes. - Animal wastes are a major contributor of nutrients and enteric microorganisms to surface water and ground water. Polyacrylamide (PAM) mixtures are an effective flocculent, and we hypothesized that they would reduce transport of microorganisms in flowing water. After waste water running at 60.0 l min{sup -1} flowed over PAM+Al{sub 2}(SO{sub 4}){sub 3}, or PAM+CaO in furrows, total coliform bacteria (TC) and fecal coliform bacteria (FC) were reduced by 30-50% at 1 and 50 m downstream of the treatments compared to the control. In a column study, PAM+Al{sub 2}(SO{sub 4}){sub 3}, and PAM+CaO applied to sandy, sandy loam, loam, and clay soils reduced NH{sub 4}{sup +} and ortho-P concentrations in leachate compared to the source waste water and the control. PAM+Al{sub 2}(SO{sub 4}){sub 3} and PAM+CaO applied to sandy, sandy loam and loam soils reduced both total and ortho-P, concentrations in leachate compared to the source wastewater and control treatment. In a field study, PAM+Al{sub 2}(SO{sub 4}){sub 3}, or PAM+CaO treatments did not consistently reduce NH{sub 4}{sup +}, NO{sub 3}{sup -}, ortho-P, and total P concentrations in wastewater flowing over any soil compared to inflow wastewater or the control treatment. With proper application PAM+ Al{sub 2}(SO{sub 4}){sub 3} and PAM+CaO may be able to reduce the numbers of enteric bacteria in slowly flowing wastewater running off animal confinement areas, reducing the amount of pollutants entering surface water and groundwater.

  12. Effect of ISPAD Anaerobic Digestion on Ammonia Volatilization from Soil Applied Swine Manure

    Directory of Open Access Journals (Sweden)

    Susan King

    2012-01-01

    Full Text Available Swine manure subjected to in-storage psychrophilic anaerobic digestion (ISPAD undergoes proteins degradation but limited NH3 volatilization, producing an effluent rich in plant-available nitrogen. Accordingly, ISPAD effluent can offer a higher fertilizer value during land application, as compared to manure of similar age stored in an open tank. However, this additional nitrogen can also be lost by volatilization during land application. The objective of this study was therefore to measure NH3 volatilization from both ISPAD and open tank swine manures when applied to 5 different soils, namely, washed sand, a Ste Rosalie clay, an Upland sandy loam, a St Bernard loam, and an Ormstown loam. This research was conducted using laboratory wind tunnels simulating land application. The five experimental soils offered similar pH values but different water holding capacity, cation exchange capacity, cation saturation, and organic matter. After 47 h of wind tunnel monitoring, the % of total available nitrogen (TAN or NH4 + and NH3 volatilized varied with both manure and soil type. For all soil types, the ISPAD manure consistently lost less NH3 as compared to the open tank manure, averaging 53% less. Lower volatile solids content improving manure infiltration into the soil and a more complex ionic solution explain the effect of the ISPAD manure advantages. This was reinforced by the St Bernard sandy loam losing the same nitrogen mass for both manures, because of its higher pH and buffer pH coupled with an intermediate CEC resulting in more soil solution NH3. Within each manure type, % TAN volatilized was highest for washed sand and lowest for the clay soil. As a result, ISPAD manure can offer up to 21% more plant-available nitrogen fertilizer especially when the manure is not incorporated into the soil following its application.

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

    Science.gov (United States)

    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%.

  14. Benthic foraminifers as indices of diversity and hyposalinity in a modern clastic shelf regime, off Bombay, India

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.; Nigam, R.

    -20 m at submerged depth. Sub-Recent foraminiferal populations and their diversity are noticeably low at stations near the sand bar while relatively high in the clay substrate. Miliolids are abundant in the sandy and silty substrates. @iAmmonia...

  15. Gypsum crystals in the inner shelf sediments off Maharashtra, India

    Digital Repository Service at National Institute of Oceanography (India)

    Hashimi, N.H.; Ambre, N.V.

    Gypsum crystals have been found in the inner shelf silty clay/clayey silt off the Maharashtra Coast between Vengurla and Bombay. Generally these occur as euhedral single or twinned crystals of selenite. Very often shells are found embedded within...

  16. Sorption and desorption of Sr-90 and Cs-137 by sediments of the Sozh-river valley and border water collections

    International Nuclear Information System (INIS)

    Onoshko, M.P.

    2001-01-01

    collections taking into account landscape conditions and lithologic breed features. The sediments of various genesis and granulometric structure were investigated in the number of complexes: breeds of the water collection (starved clay, loam, humus light loam, sandy loam) and breeds of the valley (meadow marl, peat, humus horizon of buried soil, loam). Characteristics of the sediment structure used in experiment are given in the table. The model samples enriched by Sr-90 and Cs-137 were prepared for experiments. Amounts of the radioisotopes absorbed by sediments of different of structure, practically did not differ and did not depend on capacity of absorption of a sample. It means that cation-exchange abilities of samples are higher, than radioisotope amounts in a solution, therefore their absorption by soils and exchange with the absorbed bases is provided by minimal sorption abilities. In the desorption experiments breed samples after interaction with radioisotopes was filled by leaching-out solution taken in the ratio 1:20. The further processing of samples was carried out according to the method described above at saturation by radioisotopes. For radiocaesium the desorption value, according to the received data, grows from valley sediments to the sediments from water collection. Water collection breeds give back this isotope better, than sediments of the valley. High desorption ability to Cs-137 of sandy and light loamy sediments of the water collection by all reagents (35,4-57,8 %) may promote secondary redistribution of this radioisotope. Its fixation in breeds of the water collections, is especial in starved loam, below, than at valley sediments. One of the possible reasons of the observably order of the increase of durability of connection of the isotope with sorption breeds complexes are distinctions in exchange capacity. The efficiency of all reagents that replace Cs-137 from the water collections sediments are close. Desorption radiostrontium just as for

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

    Science.gov (United States)

    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.

  18. Gas transport and subsoil pore characteristics

    DEFF Research Database (Denmark)

    Berisso, Feto Esimo; Schjønning, Per; Keller, Thomas

    2013-01-01

    Arrangements of elementary soil particles during soil deposition and subsequent biological and physical processes in long-term pedogenesis are expected to lead to anisotropy of the non-tilled subsoil pore system. Soil compaction by agricultural machinery is known to affect soil pore characteristics...... were sampled in vertical and horizontal directions from 0.3, 0.5, 0.7 and 0.9 m depth (the two lower depths only in Sweden). In the laboratory, water retention, air permeability (ka) and gas diffusivity (Ds/D0) were determined. For the sandy clay loam, morphological characteristics of pores (effective......). In the sandy clay loam soil, dB and nB displayed significant anisotropy (FAcharacteristics because of its origin...

  19. Effect of aggregate structure on VOC gas adsorption onto volcanic ash soil.

    Science.gov (United States)

    Hamamoto, Shoichiro; Seki, Katsutoshi; Miyazaki, Tsuyoshi

    2009-07-15

    The understanding of the gaseous adsorption process and the parameters of volatile organic compounds such as organic solvents or fuels onto soils is very important in the analysis of the transport or fate of these chemicals in soils. Batch adsorption experiments with six different treatments were conducted to determine the adsorption of isohexane, a gaseous aliphatic, onto volcanic ash soil (Tachikawa loam). The measured gas adsorption coefficient for samples of Tachikawa loam used in the first three treatments, Control, AD (aggregate destroyed), and AD-OMR (aggregate destroyed and organic matter removed), implied that the aggregate structure of volcanic ash soil as well as organic matter strongly enhanced gas adsorption under the dry condition, whereas under the wet condition, the aggregate structure played an important role in gas adsorption regardless of the insolubility of isohexane. In the gas adsorption experiments for the last three treatments, soils were sieved in different sizes of mesh and were separated into three different aggregate or particle size fractions (2.0-1.0mm, 1.0-0.5mm, and less than 0.5mm). Tachikawa loam with a larger size fraction showed higher gas adsorption coefficient, suggesting the higher contributions of macroaggregates to isohexane gas adsorption under dry and wet conditions.

  20. Mixtures of coal ash and compost as substrates for highbush blueberry

    Energy Technology Data Exchange (ETDEWEB)

    Black, B.L.; Zimmerman, R.H. [ARS, Beltsville, MD (USA). USDA Henry A Wallace Beltsville Agriculture Research Center, Fruit Lab.

    2002-07-01

    Bottom ash from a coal-fired power plant and two composts were tested as components of soil-free media and as soil amendments for growing highbush blueberry (Vaccinium corymbosum L.). Combinations of ash and compost were compared to Berryland sand, and Manor clay loam, and compost amended Manor clay loam. The pH of all treatment media was adjusted to 4.5 with sulfur at the beginning of the experiment. In 1997, plants of 'Bluecrop' and 'Sierra' were planted in 15-dm{sup 3} pots containing the pH-adjusted treatment media. The first substantial crop was harvested in 1999. At the end of the 1999 season, one half of the plants were destructively harvested for growth analysis. The remaining plants were cropped again in 2000. Yield and fruit size data were collected in both seasons, and leaf and fruit samples were collected in 1999 for elemental analysis. The presence of coal ash or composted biosolids in the media had no detrimental effect on leaf or fruit elemental content. Total growth and yield of both cultivars was reduced in clay loam soil compared to Berryland sand, whereas growth and yield of plants in coal ash-compost was similar to or exceeded that of plants in Berryland sand.

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

    Science.gov (United States)

    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.

  2. Research Note:Determination of soil hydraulic properties using pedotransfer functions in a semi-arid basin, Turkey

    Directory of Open Access Journals (Sweden)

    M. Tombul

    2004-01-01

    Full Text Available Spatial and temporal variations in soil hydraulic properties such as soil moisture q(h and hydraulic conductivity K(q or K(h, may affect the performance of hydrological models. Moreover, the cost of determining soil hydraulic properties by field or laboratory methods makes alternative indirect methods desirable. In this paper, various pedotransfer functions (PTFs are used to estimate soil hydraulic properties for a small semi-arid basin (Kurukavak in the north-west of Turkey. The field measurements were a good fit with the retention curve derived using Rosetta SSC-BD for a loamy soil. To predict parameters to describe soil hydraulic characteristics, continuous PTFs such as Rosetta SSC-BD (Model H3 and SSC-BD-q33q1500 (Model H5 have been applied. Using soil hydraulic properties that vary in time and space, the characteristic curves for three soil types, loam, sandy clay loam and sandy loam have been developed. Spatial and temporal variations in soil moisture have been demonstrated on a plot and catchment scale for loamy soil. It is concluded that accurate site-specific measurements of the soil hydraulic characteristics are the only and probably the most promising method to progress in the future. Keywords: soil hydraulic properties, soil characteristic curves, PTFs

  3. Structure and Composition of Leachfield Bacterial Communities: Role of Soil Texture, Depth and Septic Tank Effluent Inputs

    Directory of Open Access Journals (Sweden)

    Janet A. Atoyan

    2012-09-01

    Full Text Available Although groundwater quality depends on microbial processes in the soil treatment area (STA of onsite wastewater treatment systems (OWTS, our understanding of the development of these microbial communities is limited. We examined the bacterial communities of sand, sandy loam, and clay STAs at different depths in response to septic tank effluent (STE addition using mesocosms. Terminal restriction fragment length polymorphism (TRFLP analysis was used to compare the bacterial community structure and composition of STE, native soil prior to STE addition (UNX and soil exposed to STE (EXP. Principal component analysis separated communities with depth in sand but not in sandy loam or clay. Indices of richness, diversity, and evenness followed the order: sandy loam > sand > clay. Analysis of TRF peaks indicated that STE contributed least to the composition of STA bacterial communities (5%–16%, followed by UNX soil (18%–48%, with the highest proportion of the community made up of TRFs not detected previously in either UNX or STE (50%–82% for all three soils. Soil type and depth can have a marked effect on the structure and composition of STA bacterial communities, and on the relative contribution of native soil and STE to these communities.

  4. Abundance of plankton population densities in relation to bottom soil textural types in aquaculture ponds

    Directory of Open Access Journals (Sweden)

    F. Siddika

    2012-06-01

    Full Text Available Plankton is an important food item of fishes and indicator for the productivity of a water body. The present study was conducted to evaluate the effects of bottom soil textural conditions on abundance of plankton in aquaculture pond. The experiment was carried out using three treatments, i.e., ponds bottom with sandy loam (T1, with loam (T2 and with clay loam (T3. The ranges of water quality parameters analyzed were suitable for the growth of plankton during the experimental period. Similarly, chemical properties of soil were also within suitable ranges and every parameter showed higher ranges in T2. A total 20 genera of phytoplankton were recorded belonged to Chlorophyceae (7, Cyanophyceae (5, Bacillariophyceae (5, Euglenophyceae (2 and Dinophyceae (1. On the other hand, total 13 genera of zooplankton were recorded belonged to Crustacea (7 and Rotifera (6. The highest ranges of phytoplankton and zooplankton densities were found in T2 where low to medium-type bloom was observed during the study period. Consequently, the mean abundance of plankton (phytoplankton and zooplankton density was significantly highest in T2. The highest abundance of plankton in the T2 indicated that pond bottom with loamy soil is suitable for the growth and production of plankton in aquaculture ponds.

  5. application of used engine oil on of used engine oil in soil on of ...

    African Journals Online (AJOL)

    eobe

    Keywords: soil stabilization, used engine oil, s. 1. INTRODUCTION ... cement, lime, fly ash and a combination of ot additives is meant to ... California bearing ratio (CBR) of the soil. This p of the soil. ... range of silty-clay and sandy. CBR of ...

  6. Water balance of two earthen landfill caps in a semi-arid climate

    International Nuclear Information System (INIS)

    Khire, M.V.; Benson, C.H.; Bosscher, P.J.

    1997-01-01

    Water balance data are presented that were obtained from two earthen cap test sections located in a semi-arid region. The test sections were constructed on a municipal solid waste landfill in East Wenatchee, Washington, USA. One test section represents a traditional resistive barrier, and is constructed with a compacted silty clay barrier 60 cm thick and a vegetated silty clay surface layer 15 cm thick. The other test section represents a capillary barrier and has a sand layer 75 cm thick overlain by a 15-cm-thick vegetated surface layer of silt. Extensive hydrological and meteorological data have been collected since November 1992. Unsaturated hydraulic properties of soils, hydrologic parameters, and vegetation have been extensively characterized. Results of the study show that capillary barriers can be effective caps in semi-arid and arid regions. They are also cheaper to construct and can perform better than traditional resistive barriers

  7. Field Test Evaluation of Effect on Cone Resistance Caused by Change in Penetration Rate

    DEFF Research Database (Denmark)

    Poulsen, Rikke; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

    2012-01-01

    in the laboratory. A change in the measured cone resistance occurs by lowering the penetration rate. This is caused by the changes in drainage conditions. Compared to the normal penetration rate of 20 mm/s, this paper illustrates that lowering the penetration rate leads to an increase in the cone resistance from 1......This paper presents how a change in cone penetration rate affects the measured cone resistance during cone penetration testing in silty soils. Regardless of soil, type the standard rate of penetration is 20 mm/s and it is generally accepted that undrained penetration occurs in clay while drained...... penetration occurs in sand. In intermediate soils such as silty soils, the standard cone penetration rate may result in drainage conditions varying from undrained to partially or fully drained conditions. Field cone penetrations tests have been conducted with different penetration rates on a test site...

  8. A Case Study on Stratified Settlement and Rebound Characteristics due to Dewatering in Shanghai Subway Station

    Directory of Open Access Journals (Sweden)

    Jianxiu Wang

    2013-01-01

    Full Text Available Based on the Yishan Metro Station Project of Shanghai Metro Line number 9, a centrifugal model test was conducted to investigate the behavior of stratified settlement and rebound (SSR of Shanghai soft clay caused by dewatering in deep subway station pit. The soil model was composed of three layers, and the dewatering process was simulated by self-invention of decompressing devise. The results indicate that SSR occurs when the decompression was carried out, and only negative rebound was found in sandy clay, but both positive and negative rebound occurred in the silty clay, and the absolute value of rebound in sandy clay was larger than in silty clay, and the mechanism of SSR was discussed with mechanical sandwich model, and it was found that the load and cohesive force of different soils was the main source of different responses when decompressed.

  9. Elements of the tsunami precursors' detection physics

    Science.gov (United States)

    Novik, Oleg; Ruzhin, Yuri; Ershov, Sergey; Volgin, Max; Smirnov, Fedor

    In accordance with the main physical principles and geophysical data, we formulated a nonlinear mathematical model of seismo-hydro-electromagnetic (EM) geophysical field interaction and calculated generation and propagation of elastic, EM, temperature and hydrodynamic seismically generated disturbances (i.e. signals) in the basin of a marginal sea. We show transferring of seismic and electromagnetic (EM) energy from the upper mantle beneath the sea into its depths and EM emission from the sea surface into the atmosphere. Basing on the calculated characteristics of the signals of different physical nature (computations correspond to measurements of other authors) we develop the project of a Lithosphere-Ocean-Atmosphere Monitoring System (LOAMS) including: a bottom complex, a moored ocean surface buoy complex, an observational balloon complex, and satellite complex. The underwater stations of the bottom complex of the LOAMS will record the earlier signals of seismic activation beneath a seafloor (the ULF EM signals outrun seismic ones, according to the above calculations) and localize the seafloor epicenter of an expected seaquake. These stations will be equipped, in particular, with: magnetometers, the lines for the electric field measurements, and magneto-telluric blocks to discover dynamics of physical parameters beneath a sea floor as signs of a seaquake and/or tsunami preparation process. The buoy and balloon complexes of the LOAMS will record the meteorological and oceanographic parameters' variations including changes of reflection from a sea surface (tsunami ‘shadows’) caused by a tsunami wave propagation. Cables of the balloon and moored buoy will be used as receiving antennas and for multidisciplinary measurements including gradients of the fields (we show the cases are possible when the first seismic EM signal will be registered by an antenna above a sea). Also, the project includes radio-tomography with satellite instrumentation and sounding of the

  10. Total Stem and Merchantable Volume Equations of Norway Spruce (Picea abies (L. Karst. Growing on Former Farmland in Sweden

    Directory of Open Access Journals (Sweden)

    Tord Johansson

    2014-08-01

    Full Text Available An equation was constructed to estimate the stem volume of Norway spruce (Picea abies (L. Karst. in 145 stands growing on former farmland in Sweden (Latitude 56–63° N. The mean total age was 40 ± 13 (range 17–91 years, the mean diameter at breast height (ob was 15 ± 4 (range 5–27 cm and the mean density was 1621 ± 902 (range 100–7600 stems ha−1. The equation which fits the data best used the diameter at breast height and total stem height as predictive variables. Merchantable volume equations for the estimation of commercial volume for any top diameter and bole length were developed. Soil types in the stands were sediments (coarse sand, fine sand and silt and heavy, medium and light clay, tills (sandy, fine sandy and silty and peat. The standing volume was calculated; the mean was 253 ± 103 (range 26–507 m3 ha−1 with a MAI (mean annual increment of 6.9±3.5 (range 1.3–16.7 m3 ha−1 year−1. There were statistically significant differences between MAI and coarse sand, sand and silt, light clay, peat and silty till soils. Spruce stands growing on silty tills had the lowest MAI (4.94 ± 2.27 m3 ha−1 year−1 and light clay, fine sand and silt and peat the highest (7.62 ± 4.24, 7.46 ± 3.33 and 8.67 ± 2.83 m3 ha−1 year−1.

  11. Water and nutrient productivity in melon crop by fertigation under subsurface drip irrigation and mulching in contrasting soils

    Directory of Open Access Journals (Sweden)

    Rodrigo Otávio Câmara Monteiro

    2014-01-01

    Full Text Available Cropping intensification and technical, economic and environmental issues require efficient application of production factors to maintain the soil productive capacity and produce good quality fruits and vegetables. The production factors, water and NPK nutrients, are the most frequent limiting factors to higher melon yields. The objective of the present study was to identify the influence of subsurface drip irrigation and mulching in a protected environment on the water and NPK nutrients productivity in melon cropped in two soil types: sandy loam and clay. The melon crop cultivated under environmental conditions with underground drip irrigation at 0.20m depth, with mulching on sandy loam soil increased water and N, P2O5 and K use efficiency.

  12. Mobility and retention of micronutrients in soil : Part III. Investigation on the influence of various external factors, NPK-fertilizers and soil amending agents on the mobility and retention of manganese

    International Nuclear Information System (INIS)

    Das, S.K.; Santikari, A.K.; Banerji, K.C.

    1980-01-01

    Investigations on the mobility and retention of manganese through Sindri red sandy clay loam of pH 7.4 and Ranchi clay loam of pH 5.6 have been carried out using the radiotracer 54 Mn. The vertical distribution of manganese in these soils showed almost sharp fall upto a depth of 12 to 14 cm and thereafter it tended to attain the saturation. Variations have been marked in the degrees of manganese retention at the top surface layers of the concerned soils. Influence of various NPK fertilizers and soil amending agents, at various application levels, have been studied on the mobility, retention and leaching loss of manganese in the prementioned soils. Marked variations have been recorded and discussed. (author)

  13. Quantitative distribution of meiobenthos in the Gulf of Martaban, Myanmar Coast, north-east Andaman Sea.

    Digital Repository Service at National Institute of Oceanography (India)

    Ansari, Z.A.; Mehta, P.; Furtado, R.; Aung, C.; Pandiyarajan, R.S.

    .428 mg/10 cm2 in different sediment type and depth zone. Numerical abundance of meiofauna was high in fine silty clay and low in sandy bottom. Formation of three main clusters suggests the influence of dominant sediment texture of clayey sand sand silt...

  14. Shallow stratigraphy and gas-charged sediments in the inner shelf off Redi, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Subbaraju, L.V.

    palaeochannel running across the region in ENE-WSW direction. Shallow seismic surveys indicate a pseudo escapment of more than 7 m deep between 12-14 m water depths. Eastern part (11-14 m) of the escarpment indicate the existence of gas-charged sediments (silty...

  15. Effect of Tractor Forward Speed on Sandy Loam Soil Physical ...

    African Journals Online (AJOL)

    Results indicate significant differences in soil physical conditions arising from different levels of tractor forward speed. A forward speed of approximately 7km/h resulted in appreciable amelioration of soil structure as reflected in improvements in the soil strength properties and maximum reduction in clod mean weight ...

  16. Enhanced isoproturon mineralisation in a clay silt loam agricultural soil

    OpenAIRE

    El-Sebai , T.; Lagacherie , B.; Cooper , J.F.; Soulas , G.; Martin-Laurent , F.

    2005-01-01

    International audience; 14C-ring-labelled isoproturon mineralisation was investigated in a French agricultural soil previously exposed to isoproturon. 50 different soil samples collected every 2 m along a transect of 100 m in length were treated one or two times with isoproturon under laboratory conditions and analysed by radiorespirometry. 94% of the soil samples showed a high ability to mineralise isoproturon with a relatively low variability in the cumulative percentage of mineralisation r...

  17. SUPERFUND TREATABILITY CLEARINGHOUSE: FINAL REPORT: ON-SITE INCINERATION OF SHIRCO INFRARED SYSTEMS PORTABLE PILOT TEST UNIT, TIMES BEACH, MISSOURI

    Science.gov (United States)

    During the period of July 8 - July 12, 1985, the Shirco Infrared Systems Portable Pilot Test Unit was in operation at the Times Beach Dioxin Research Facility to demonstrate the capability of Shirco's infrared technology to decontaminate silty soil laden with 2,3,7,8-tetrachlorod...

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

    Science.gov (United States)

    Briassoulis, D; Mistriotis, A

    2018-05-05

    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.

  19. Impact of pulp and paper mill effluents and solid wastes on soil mineralogical and physicochemical properties.

    Science.gov (United States)

    Adhikari, Gopi; Bhattacharyya, Krishna G

    2015-03-01

    The present study was carried out to evaluate the impact of the effluents and the solid wastes generated by a giant pulp and paper mill in the northeastern part of India on soil mineralogy of the area. The impacts were monitored by analysis of soil samples from seven sites located in the potential impact zone and a control site where any kind of effluent discharge or solid waste dumping was absent. The soil belonged to medium texture type (sandy clay loam, sandy loam, loamy sand, and silt loam), and the soil aggregate analysis indicated higher levels of organic carbon, pH, electrical conductivity, effective cation exchange capacity, and mean weight diameter at sites receiving effluents and solid wastes from the pulp and paper mill. Depletion in soil silica level and in feldspar and quartz contents and rise in iron and calcium contents at the sites receiving effluents from the pulp and paper mill indicated significant influence on soil mineralogy. The soil contained a mixture of minerals consisting of tectosilicates (with silicate frameworks as in quartz or feldspar), phylosilicates (layered clays like kaolinite, smectite, chlorite, illite, etc.), and carbonates. Absence of pure clay minerals indicated a state of heterogeneous intermediate soil clay transformation. The significance of the mixed mineralogy in relation to the disposal of effluents and dumping of solid wastes is discussed in details.

  20. Alkaline extraction: can it be used for the removal of 137Cs from soil?

    International Nuclear Information System (INIS)

    Nageldinger, G.; Flowers, A.; Entwistle, J.

    1998-01-01

    A titration extraction procedure was applied to a silty clay which was spiked with 137 Cs. At least 20% of spiked 137 Cs silty clay was found to be associated with the humic acid (HA) fraction. This shows that HA contributes significantly to cesium fixing in soil and cesium is not only fixed between regular ion exchange complexes (REC) and specific sites in the frayed edges of clay minerals (FES). About 85% of 137 Cs was found in the 12M HCl extract. The titration extraction procedure was found useful for investigation of the impact of the soil pH on the radiocesium mobility. Only trace amounts of cesium were found between pH 1 to 7, demonstrating a high immobility of cesium over this pH range. If the alkaline digestion is applied to soil for the removal of radiocesium, then these can be significantly separated from the extract by protonation of the extracted HA. (P.A.)

  1. A geological reconnaissance study of the Dyfi Valley region, Gwynedd/Powys, Wales

    International Nuclear Information System (INIS)

    Martin, B.A.; Howells, M.F.; Reedman, A.J.

    1981-01-01

    A collation of existing maps and data backed up by localised checking, reinterpretation and modification, employing sampling, structural measurements and aerial photograph interpretation, have updated the geological information available on the Dyfi Valley region. The region comprises an argillaceous-dominated Ordovician and Silurian sedimentary pile of approximately 4 km thickness. Thick formations of mudstones and silty mudstones with thin intercalations of silty sandstone and fine-grained sandstone predominate and exhibit fewer variations in thickness and extent than the subordinate formations with a higher proportion of sand-grade material. Three periods of deformation (D 1 -D 3 ) are distinguished, with the D 1 phase dominating the structure of the region by forming upright, asymmetrical, large (km) scale folds (F 1 ) of a NNE-SSW to NE-SW trend and producing an almost ubiquitous slaty cleavage (S 1 ). The succeeding deformations produced localised crenulation cleavages, kink bands and box folds. Data on the faulting and jointing associated with this deformation history are also presented. (author)

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

    Science.gov (United States)

    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

  3. an ecological study on rodents of natural vegetation and farm lands ...

    African Journals Online (AJOL)

    preferred customer

    habitat association of rodents was conducted in Siltie natural vegetation and nearby farmlands ... In each habitat type, one representative grid was selected for live trapping. In addition, rodents were also snap- trapped from these habitats. A total of 562 captures was made .... into seeds, leaves, roots, earthworms and arthro-.

  4. Autoclave decomposition method for metals in soils and sediments.

    Science.gov (United States)

    Navarrete-López, M; Jonathan, M P; Rodríguez-Espinosa, P F; Salgado-Galeana, J A

    2012-04-01

    Leaching of partially leached metals (Fe, Mn, Cd, Co, Cu, Ni, Pb, and Zn) was done using autoclave technique which was modified based on EPA 3051A digestion technique. The autoclave method was developed as an alternative to the regular digestion procedure passed the safety norms for partial extraction of metals in polytetrafluoroethylene (PFA vessel) with a low constant temperature (119.5° ± 1.5°C) and the recovery of elements were also precise. The autoclave method was also validated using two Standard Reference Materials (SRMs: Loam Soil B and Loam Soil D) and the recoveries were equally superior to the traditionally established digestion methods. Application of the autoclave was samples from different natural environments (beach, mangrove, river, and city soil) to reproduce the recovery of elements during subsequent analysis.

  5. Investigation of the transport of actinide-bearing soil colloids in the soil-aquatic environment

    International Nuclear Information System (INIS)

    Sheppard, J.C.; Campbell, M.J.; Kittrick, J.; Cheng, T.

    1980-04-01

    Uranium-233 particle size dependent distribution ratios for the 10 to 60 range were determined for muscatine silt loam, Burbank loamy sand, Ritzville silt loam, Fuquay sand, and Idaho sandy clay. A mathematical method for the analysis of centrifuge data was developed to determine particle size dependent distribution ratio for the 10 to 60 nm range. Comparison of the distribution ratio data for the 0 to 60 nm particle size range strongly suggests that particles in the 1 to 10 nm (8000 to 50,000 MW) range play a dominate role. Since these particles are probably humic acid polymers, future research should be focused on humic acid complexing of radionuclides. A mathematical analysis is given to demonstrate the role of humic acid complexing in the transport of radionuclides in the soil-aquatic environment

  6. Leaching of human pathogens in repacked soil lysimeters and contamination of potato tubers under subsurface drip irrigation in Denmark

    DEFF Research Database (Denmark)

    Forslund, Anita; Plauborg, Finn; Andersen, Mathias Neumann

    2011-01-01

    The risk for contamination of potatoes and groundwater through subsurface drip irrigation with low quality water was explored in 30 large-scale lysimeters containing repacked coarse sand and sandy loam soils. The human pathogens, Salmonella Senftenberg, Campylobacter jejuni and Escherichia coli O......, phage 28B was detected in low concentrations (2 pfu ml1) in leachate from both sandy loam soil and coarse sand lysimeters. After 27 days, phage 28B continued to be present in similar concentrations in leachate from lysimeters containing coarse sand, while no phage were found in lysimeters with sandy....... The findings of bacterial pathogens and phage 28 on all potato samples suggest that the main risk associated with subsurface drip irrigation with low quality water is faecal contamination of root crops, in particular those consumed raw....

  7. LNAPL source zone delineation using soil gases in a heterogeneous silty-sand aquifer

    Science.gov (United States)

    Cohen, Grégory J. V.; Jousse, Florie; Luze, Nicolas; Höhener, Patrick; Atteia, Olivier

    2016-09-01

    Source delineation of hydrocarbon contaminated sites is of high importance for remediation work. However, traditional methods like soil core extraction and analysis or recent Membrane Interface Probe methods are time consuming and costly. Therefore, the development of an in situ method based on soil gas analysis can be interesting. This includes the direct measurement of volatile organic compounds (VOCs) in soil gas taken from gas probes using a PID (Photo Ionization Detector) and the analysis of other soil gases related to VOC degradation distribution (CH4, O2, CO2) or related to presence of Light Non-Aqueous Phase Liquid (LNAPL) as 222Rn. However, in widespread heterogeneous formations, delineation by gas measurements becomes more challenging. The objective of this study is twofold: (i) to analyse the potential of several in situ gas measurement techniques in comparison to soil coring for LNAPL source delineation at a heterogeneous contaminated site where the techniques might be limited by a low diffusion potential linked to the presence of fine sands and silts, and (ii) to analyse the effect of vertical sediment heterogeneities on the performance of these gas measurement methods. Thus, five types of gases were analysed: VOCs, their three related degradation products O2, CO2 and CH4 and 222Rn. Gas measurements were compared to independent LNAPL analysis by coring. This work was conducted at an old industrial site frequently contaminated by a Diesel-Fuel mixture located in a heterogeneous fine-grained aquifer. Results show that in such heterogeneous media migration of reactive gases like VOCs occurs only across small distances and the VOC concentrations sampled with gas probes are mainly related to local conditions rather than the presence of LNAPL below the gas probe. 222Rn is not well correlated with LNAPL because of sediment heterogeneity. Oxygen, CO2, and especially CH4, have larger lengths of diffusion and give the clearest picture for LNAPL presence at this site even when the gas probe is somewhat distant.

  8. Estimation of Effective Stress From Bishop’s Parameter c for a Silty Sand

    Directory of Open Access Journals (Sweden)

    Rojas-González Eduardo

    2013-04-01

    Full Text Available El comportamiento de resistencia y cambios volumétricos de un suelo saturado están controlados por los esfuerzos efectivos, sin embargo, para el caso de los suelos no saturados no ha sido posible esclarecer este argumento. No existe una ecuación de esfuerzos efectivos para los suelos no saturados que sea aplicable a todos los tipos de suelos. Bishop (1959 propuso una ecuación para esfuerzos efectivos para suelos no saturados, esta ecuación contiene el parámetro c; para determinar este parámetro existen varias ecuaciones pero ninguna comprende todos los casos. Por otra parte, en la mecánica de suelos se ha considerado que la resistencia cortante de los suelos finos se incrementa con la succión; sin embargo, esto no es el caso para todos los tipos de suelos. Existen algunos suelos cuya resistencia alcanza un máximo para cierta succión y luego se reduce para valores mayores de succión, no obstante, tales casos aún no han sido completamente documentados y analizados. Este artículo presenta una serie de pruebas triaxiales con succión controlada en laboratorio hechas en una arena limosa. Las pruebas se hicieron para las trayectorias de humedecimiento y secado. La succión se controló mediante circulación de aire con humedad relativa constante. La curva de retención de agua fue también obtenida para ambas trayectorias de humedecimiento y secado con la técnica del papel filtro, y para la trayectoria de secado se hicieron pruebas con el cilindro extractor de membrana. Los resultados de las pruebas triaxiales se muestran en diagramas p’-q y se ha podido observar que la resistencia del suelo crece a un máximo para cierta succión y luego decrece para valores mayores de succión, también se han incluido los valores de c obtenidos de algunas ecuaciones existentes para este parámetro y resultados experimentales.

  9. Experimental study of silty clay stabilization with cement and lime in multan, pakistan

    International Nuclear Information System (INIS)

    Sultan, T.

    2014-01-01

    Stabilization is valuable substitute for advancing the soil characteristics. The engineering features gained after stabilization differs broadly owing to non-uniformity in constitutions of soil. This study describes an assessment of cement and lime additives for advancing soils ventures. The effectiveness of lime and cement stabilization on geotechnical characteristics of the in situ soil has also been described in the paper. The additives like cement and lime were added in different dosage rates to examine the change in properties of the in situ soil. Cement addition caused an increase in unconfined compression strength (UCS) throughout from 4% to 16% of cement. Moreover, it has been observed that by adding lime, the early strength of clay increases up to 6% of lime but for long term strength i.e. 28 days maximum strengths is achieved for 4% of lime. It also confirms that with more percentage of lime and longer duration of curing, it expands. In addition to the strength behavior of samples at various percentages of cement and lime, the deflection at failure point was also examined. In order to make a straight comparison, both cement and lime stabilized soils were also tested in laboratory. Generally, the performance of Portland cement-stabilized soils was advanced to lime in the experiments performed. (author)

  10. Modelos de infiltración y funciones de pedotransferencia aplicados a suelos de distinta textura Infiltration models and pedotransfer functions applied to soils with different texture

    Directory of Open Access Journals (Sweden)

    Ana M Landini

    2007-12-01

    las hipótesis del modelo.The knowledge of the process of water infiltration in soil is important in the design of irrigation systems and in the prediction of the vulnerability to the contamination of soil and groundwater. Moreover, it is important to evaluate the efficiency of the hydrological models that predict the movement of water in soil. The objective of this study was to evaluate and to compare the goodness of fitting of Kostiakov-Lewis (K-L and Philip (Ph infiltration models to experimental data obtained from three soils: two of them at the Province of Buenos Aires, and the third one at the School of Agronomy's campus of the Buenos Aires University, (Argentina. Efficiency of Saxton and Rawls (SyR pedotransfer functions (FPT on the determination of the Green and Ampt (GA model input hydraulic parameters and the prediction of the soil-moisture release curve were analyzed too. K-L and Ph models fitted data with R² coefficient greater than 0.6. Then it was concluded that these models accurately describe the infiltration process of the studied soils. The highest basic infiltration rate (fo was 0.42 cm min-1 and corresponded to a silty clay soil with organic amendment, and for the other two soils (silt loam and clay loam were 0.03 and 0.07 cm min-1 respectively. For two of the studied soils, GA model obtained from input parameters determined with the FPT, predicted the infiltration process with an efficiency coefficient (CE greater than 0.8. However, at some cases, the fitting was not so good for dephts greater than 20 cm. For the silt loam soil, the FPT predicted the soil-moisture release curve with an CE close to 0.9. It might be suggested to carry out a preliminary few number of infiltration tests on any soil under study, and analyze the FPT and the GA model goodness of fit. In this way, the convenience of using these models could be evaluated.

  11. Ecological Assessment of Lake Hora, Ethiopia, Using Benthic and ...

    African Journals Online (AJOL)

    Bheema

    Lake Hora needs protection management strategies to maintain its sustainable use. Key words: Benthic Fauna, Ethiopia, Lake Hora, Specimens, Weed-bed. 1. ..... Loam soils often contain a good amount of organic matter. 3.3. Ecological ...

  12. In Vitro antibacterial activity of rumex nervosus, plantago lanceolata ...

    African Journals Online (AJOL)

    determined by agar dilution assay based on the zone of bacterial growth inhibition. ... trees such as eucalyptus and acacia. The soil type is dominantly sandy loam .... However, a range of pharmacological properties has been found in.

  13. Effects of crust and cracks on simulated catchment discharge and soil loss

    NARCIS (Netherlands)

    Stolte, J.; Ritsema, C.J.; Roo, de A.P.J.

    1997-01-01

    Sealing, crusting and cracking of crusts of the soil surface has been observed in many parts of the world in areas with sandy, silty and loamy soils. Sealing and crust formation occurs under the influence of rain storm and drying weather. With prolonged drying, surface crusts might crack, leading to

  14. Increasing cotton stand establishment in soils prone to soil crusting

    Science.gov (United States)

    Many factors can contribute to poor cotton stand establishment, and cotton is notorious for its weak seedling vigor. Soil crusting can be a major factor hindering cotton seedling emergence in many of the cotton production regions of the US and the world. Crusting is mainly an issue in silty soils ...

  15. Aspects of Geophysical Exploration for Groundwater Using Vertical ...

    African Journals Online (AJOL)

    MICHAEL HORSFALL

    3666.4m); wet laterite, (44.017-2201m); anomalous soil, (601.03-. 1450m); clayed/silty sand, (2712.38-11741m); dry sand, and (2909.7-12423m); as aquifer. The results reveal depth to water table ranges of 31.2-65.5m. The range of values of.

  16. Journal of Earth System Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 123; Issue 2 ... Trend analysis and change point detection of annual and seasonal .... Numerical evaluation of seismic response of shallow foundation on loose silt and silty sand ... complex interactions can be a valuable tool to gain new insights for improved seismic ...

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

    Science.gov (United States)

    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

  18. Upland cotton growth and yield response to timing the initial postplant irrigation

    International Nuclear Information System (INIS)

    Steger, A.J.; Silvertooth, J.C.; Brown, P.W.

    1998-01-01

    Cotton (Gossypium spp.) production in arid and semiarid regions depends on well-managed irrigation systems for optimum yield and production efficiency. Water deficit stress early in the growing season can affect the subsequent growth and development of short-season cotton. A 2-yr field study was conducted in southern Arizona to determine the optimum timing of the initial postplant irrigation for a short-season upland cotton variety based on midday leaf water potential (LWP) measurements, and to evaluate the season-long effects of delayed irrigation on subsequent plant growth patterns. In both years, the short-season upland variety, DPL 20, was planted into a Pima clay loam soil [fine-silty, mixed (calcareous), thermic Typic Torrifluvent] that had received a preplant irrigation of 152 (1993) or 254 mm (1994) approximately 3 wk prior to planting. Treatments, designated T1, T2, and T3, received the initial postplant irrigation when the average midday LWP of the uppermost, fully expanded leaf measured −1.5, −1.9, and −2.3 MPa, respectively. Daily midday LWP measurements were taken using the pressure chamber technique. Soil water was measured at 25-cm depth increments using neutron attenuation. Plant height, number of mainstem nodes, nodes above white flower (NAWF), and canopy closure were measured at weekly intervals. All treatments reached maturity, as measured by NAWF ≤ 5, at approximately the same time during the growing season. Complete canopy closure was delayed in the T3 plots resulting in reduced interception and utilization of available solar radiation early in the growing season. When treatments were initiated, approximately 84% (T1), 62% (T2), and 32% (T3) of the total plant-available water (field capacity less permanent wilting point) was present in the upper 1.5 of the soil profile. Yields were 1263, 1244, and 1110 kg lint ha−1 in 1993 and 1229, 1176, and 1095 kg lint ha −1 in 1994 for T1, T2, and T3, respectively. Lint yields were significantly

  19. Suitability and Economic Viability of Light Weight Mechanical Power Sources for Mechanizing Hill Farming

    Science.gov (United States)

    Vatsa, Dinesh Kumar; Singh, Sukhbir

    2017-06-01

    Farm power and equipment role was established in agriculture beyond doubt for sustainable development but hill farming is still facing shortage of farm power and matching equipment for timely and precisely operations. A study was carried out on performance evaluation of different light weight power tillers/weeders designated as P1, P2, P3 and P4 under dry and wet land conditions to meet out the demand of farm power for mechanizing hill agriculture, particularly under small and irregular shaped terraces having high vertical intervals where it is difficult to operate commercially available power tillers. Four power tillers in the horse power range of 3.0-7.0 hp manufactured and marketed by Indian firms were tested in silty-clay-loam soil at the HPKV farm, Palampur, India. The results showed that the depth of operation was less than 80 mm with P1, P2 as well as P3 power tiller after two passes of rotary at soil moisture content of 16.4% whereas, it was 102 mm with P4. The average effective field capacity was 0.055, 0.051, 0.042 and 0.060 ha/h under dry land conditions with P1, P2, P3 and P4, respectively whereas in wetland condition the capacity was 0.042, 0.038 and 0.05 with P1, P2, and P4, respectively. P3 power tiller could not be possible to test under wet land conditions due to less ground clearance of the engine. The cost of repair and maintenance was observed to be very high in case of P1, P2 and P3 power tillers due to the occurrence of frequent breakdowns. It was construed from the study that the power tillers up to 5 hp are not suitable for seed-bed preparation but it could be used as weeder for interculture operations in wide row spaced crops. However, P4 power tiller performed better than other models under different conditions. There was saving of 50-66% in time and 66-75% cost of operation observed with different makes of power tillers as compared to bullock ploughing.

  20. Spatial variability of soil carbon, pH, available phosphorous and potassium in organic farm located in Mediterranean Croatia

    Science.gov (United States)

    Bogunović, Igor; Pereira, Paulo; Šeput, Miranda

    2016-04-01

    Soil organic carbon (SOC), pH, available phosphorus (P), and potassium (K) are some of the most important factors to soil fertility. These soil parameters are highly variable in space and time, with implications to crop production. The aim of this work is study the spatial variability of SOC, pH, P and K in an organic farm located in river Rasa valley (Croatia). A regular grid (100 x 100 m) was designed and 182 samples were collected on Silty Clay Loam soil. P, K and SOC showed moderate heterogeneity with coefficient of variation (CV) of 21.6%, 32.8% and 51.9%, respectively. Soil pH record low spatial variability with CV of 1.5%. Soil pH, P and SOC did not follow normal distribution. Only after a Box-Cox transformation, data respected the normality requirements. Directional exponential models were the best fitted and used to describe spatial autocorrelation. Soil pH, P and SOC showed strong spatial dependence with nugget to sill ratio with 13.78%, 0.00% and 20.29%, respectively. Only K recorded moderate spatial dependence. Semivariogram ranges indicate that future sampling interval could be 150 - 200 m in order to reduce sampling costs. Fourteen different interpolation models for mapping soil properties were tested. The method with lowest Root Mean Square Error was the most appropriated to map the variable. The results showed that radial basis function models (Spline with Tension and Completely Regularized Spline) for P and K were the best predictors, while Thin Plate Spline and inverse distance weighting models were the least accurate. The best interpolator for pH and SOC was the local polynomial with the power of 1, while the least accurate were Thin Plate Spline. According to soil nutrient maps investigated area record very rich supply with K while P supply was insufficient on largest part of area. Soil pH maps showed mostly neutral reaction while individual parts of alkaline soil indicate the possibility of penetration of seawater and salt accumulation in the

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

    Science.gov (United States)

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

    2010-01-01

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

  2. Are BVOC exchanges in agricultural ecosystems overestimated? Insights from fluxes measured in a maize field over a whole growing season

    Science.gov (United States)

    Bachy, Aurélie; Aubinet, Marc; Schoon, Niels; Amelynck, Crist; Bodson, Bernard; Moureaux, Christine; Heinesch, Bernard

    2016-04-01

    . Moreover, as in our region (i.e., temperate climate, silty-loam soils), SEF observed on maize were much lower than SEF currently considered by models, our results tend to lower the impact of agricultural ecosystems on BVOC exchanges.

  3. Multidecadal persistence of organic matter in soils: insights from spatially resolved investigations at the submicrometer scale

    Science.gov (United States)

    Lutfalla, Suzanne; Barré, Pierre; Bernard, Sylvain; Le Guillou, Corentin; Alléon, Julien; Chenu, Claire

    2016-04-01

    Better understanding the mechanisms responsible for the pluri-decadal persistence of carbon in soils requires well constraining the dynamics, the distribution and the chemical nature of both the soil organic carbon (SOC) and the associated mineral phases. The question we address in this work is whether different mineral species lead to different organo-mineral interactions and stabilize different quantities of SOM and different types of SOC. Here, benefiting from the unique opportunity offered by an INRA long term bare fallow (LTBF) experiment having started in 1928 in Versailles (France), we report the in-situ characterization of SOC dynamics in four clay fractions of this silty loam soil (total clays [TC, clays [CC, 0.2-2μm], intermediate clays [IC, 0.05-0.2μm] and fine clays [FC, 0-0.05μm]). The IC and FC fractions only contain smectite and illite/smectite mixed-layered clay minerals while the CC fraction also contains illite and kaolinite. In the absence of any carbon input, the plant-free LTBF clay fractions from Versailles progressively lost SOC during the first 50 years of the experiment, until they reached a seemingly stable concentration. Of note, the investigated clay fractions did not lose the same amount of SOC and do not exhibit the same final carbon concentrations. The decrease of the organic C:N ratios with LTBF duration corresponds to a progressive enrichment in N-rich SOC for all fractions which can be attributed to microbial material. Even though the speciation of SOC appears to only slightly evolve with LTBF duration, an enrichment in carboxyl and carbonyl groups is revealed by bulk-scale C-NEXAFS data for SOC from all clay fractions. In addition, STXM-based NEXAFS investigations at the submicrometer scale reveal three types of SOC-clay assemblages in addition to clay-free SOC and organic-free clays. While SOC appears mostly adsorbed onto clay surfaces within the IC and FC fractions, other protection mechanisms occur within the CC fraction

  4. Download this PDF file

    African Journals Online (AJOL)

    Effect of bush encroachment on vertical soil organic carbon distribution in a clay loam soil in Shangani ... Chemistry and Soil Research Institute, P.O. Box CY 550, Causeway, Harare, Zimbabwe .... by removal of ammonium ions by distillation.

  5. Using Agricultural Residue Biochar to Improve Soil Quality of Desert Soils

    Directory of Open Access Journals (Sweden)

    Yunhe Zhang

    2016-03-01

    Full Text Available A laboratory study was conducted to test the effects of biochars made from different feedstocks on soil quality indicators of arid soils. Biochars were produced from four locally-available agricultural residues: pecan shells, pecan orchard prunings, cotton gin trash, and yard waste, using a lab-scale pyrolyzer operated at 450 °C under a nitrogen environment and slow pyrolysis conditions. Two local arid soils used for crop production, a sandy loam and a clay loam, were amended with these biochars at a rate of 45 Mg·ha−1 and incubated for three weeks in a growth chamber. The soils were analyzed for multiple soil quality indicators including soil organic matter content, pH, electrical conductivity (EC, and available nutrients. Results showed that amendment with cotton gin trash biochar has the greatest impact on both soils, significantly increasing SOM and plant nutrient (P, K, Ca, Mn contents, as well as increasing the electrical conductivity, which creates concerns about soil salinity. Other biochar treatments significantly elevated soil salinity in clay loam soil, except for pecan shell biochar amended soil, which was not statistically different in EC from the control treatment. Generally, the effects of the biochar amendments were minimal for many soil measurements and varied with soil texture. Effects of biochars on soil salinity and pH/nutrient availability will be important considerations for research on biochar application to arid soils.

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

    Science.gov (United States)

    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 0.7), 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

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

    Science.gov (United States)

    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.

  8. Sorption – desorption of imidacloprid insecticide on Indian soils of five different locations

    Directory of Open Access Journals (Sweden)

    Shailendra Singh Chauhan

    2013-07-01

    Full Text Available Sorption-desorption processes govern the movement of all chemicals including pesticides in soils. The present investigation was undertaken to study the sorption-desorption of imidacloprid, using a batch method, on soils of five different location of India. Sorption data were fitted to Freundlich isotherm. The log K value was the highest for loam type soil (1.830 and the lowest for clay type soil (1.661. The value of 1/n was the maximum for silt loam soil (0.909 but minimum for loam soil (0.723. Simple correlation analysis indicated that among soil properties only electrical conductivity showed a higher but marginally non-significant negative correlation with log K (r = -0.826 indicating that higher concentration of solutes solutes are conducive to low sorption capacity of soil. The desorption data conformed to two surfaces Freundlich desorption isotherm. The values of 1/n1' corresponding to easily desorbed fraction of imidacloprid showed significant negative correlation with soil pH (r = -0.886, significant at p ≤0.05 but significant positive correlation with clay content (r = 0.980, significant at p ≤0.01. The desorption index for easily desorbed fraction of imidacloprid (n1’/n also had significant negative correlation with soil pH (r = 0.953, significant at p ≤0.05. From cumulative desorption data, it appeared that bioavailability of imidacloprid would be lower in neutral soil than acidic or alkaline soils.

  9. Detection of probable marker-free transgene-positive rice plants ...

    Indian Academy of Sciences (India)

    crossed progenies were first germinated in plastic trays and the 30-day-old seedlings were transplanted into the pots filled with equal volume of clay loam soil and supplemented with ... based micro-Prep method (Banerjee et al. 2009).

  10. E-SAFE©

    Science.gov (United States)

    Technical product bulletin: this surface washing agent for oil spill cleanups should be applied with pressure spray. Tilling or aerating soil will speed penetration. Sand or loam may require heavy dosage as hydrocarbon migration is rapid in these.

  11. A comparison of the morphological and physiochemical characteristics of ten carambola cultivars

    Science.gov (United States)

    Carambola (Averrhoa carambola L.) was grown on a Krome gravely loam soil (Loamy-skeletal, carbonic, hyperthermic Lithic Udorthents) in Miami, FL. Carambola morphological characteristics were determined by measuring fruit length, diameter and weight. Carambola physiochemical characteristics were det...

  12. Download this PDF file

    African Journals Online (AJOL)

    influences their usability in construction works. The grain size distributions show that ADET I is silty-clayey very gravelly sand, having 23% clay and silt. 47% sand and 30% gravel compositions. Similarly, ADET 2 could be described as gravelly silt-clayey sand with 36% clay and silt. 52% sand and 12% gravel compositions.

  13. Journal of Earth System Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science. Ali Asgari. Articles written in Journal of Earth System Science. Volume 123 Issue 2 March 2014 pp 365-379. Numerical evaluation of seismic response of shallow foundation on loose silt and silty sand · Ali Asgari Aliakbar Golshani Mohsen Bagheri · More Details Abstract ...

  14. Biomass production on saline-alkaline soils

    Energy Technology Data Exchange (ETDEWEB)

    Chaturvedi, A.N.

    1985-01-01

    In a trial of twelve tree species (both nitrogen fixing and non-fixing) for fuel plantations on saline-alkaline soil derived from Gangetic alluvium silty clay, Leucaena leucocephala failed completely after showing rapid growth for six months. Results for other species at age two showed that Prosopis juliflora had the best productivity.

  15. Savanna ant species richness is maintained along a bioclimatic gradient of increasing latitude and decreasing rainfall in northern Australia

    DEFF Research Database (Denmark)

    Andersen, Alan N.; Del Toro, Israel; Parr, Catherine L.

    2015-01-01

    of 246 species from 37 genera. Mean observed species richness pooled across sampling periods was similar at sand (85.4) and loam (82.2) sites, but was less than half this at clay sites (40.0). Ant communities were also compositionally distinct on clay soils compared with sands and loams. Individual...... genera showed variable diversity patterns, ranging from a linear increase to a linear decrease in species richness along the NATT. However, total species richness was relatively uniform along the gradient. Patterns of ant species turnover were consistent with previously recognized biogeographical......Aim: Using a standardized sampling protocol along a 600-km transect in northern Australia, we tested whether ant diversity within a single biome, tropical savanna, decreases with increasing latitude (as a surrogate of temperature) and decreasing rainfall, as is expected for biodiversity in general...

  16. Hydrogen peroxide treatment of TCE contaminated soil

    International Nuclear Information System (INIS)

    Hurst, D.H.; Robinson, K.G.; Siegrist, R.L.

    1993-01-01

    Solvent contaminated soils are ubiquitous in the industrial world and represent a significant environmental hazard due to their persistence and potentially negative impacts on human health and the environment. Environmental regulations favor treatment of soils with options which reduce the volume and toxicity of contaminants in place. One such treatment option is the in-situ application of hydrogen peroxide to soils contaminated with chlorinated solvents such as trichloroethylene (TCE). This study investigated hydrogen peroxide mass loading rates on removal of TCE from soils of varying organic matter content. Batch experiments conducted on contaminated loam samples using GC headspace analysis showed up to 80% TCE removal upon peroxide treatment. Column experiments conducted on sandy loam soils with high organic matter content showed only 25% TCE removal, even at hydrogen peroxide additions of 25 g peroxide per kg soil

  17. Organic-rich shale lithofacies geophysical prediction: A case study in the fifth organic-matter-rich interval of Paleogene Hetaoyuan Formation, Biyang Depression

    Science.gov (United States)

    Fei, S.; Xinong, X.

    2017-12-01

    The fifth organic-matter-rich interval (ORI 5) in the He-third Member of the Paleogene Hetaoyuan Formation is believed to be the main exploration target for shale oil in Biyang Depression, eastern China. An important part of successful explorating and producing shale oil is to identify and predict organic-rich shale lithofacies with different reservoir capacities and rock geomechanical properties, which are related to organic matter content and mineral components. In this study, shale lithofacies are defined by core analysis data, well-logging and seismic data, and the spatial-temporal distribution of various lithologies are predicted qualitatively by seismic attribute technology and quantitatively by geostatistical inversion analysis, and the prediction results are confirmed by the logging data and geological background. ORI 5 is present in lacustrine expanding system tract and can be further divided into four parasequence sets based on the analysis of conventional logs, TOC content and wavelet transform. Calcareous shale, dolomitic shale, argillaceous shale, silty shale and muddy siltstone are defined within ORI 5, and can be separated and predicted in regional-scale by root mean square amplitude (RMS) analysis and wave impedance. The results indicate that in the early expansion system tract, dolomitic shale and calcareous shale widely developed in the study area, and argillaceous shale, silty shale, and muddy siltstone only developed in periphery of deep depression. With the lake level rising, argillaceous shale and calcareous shale are well developed, and argillaceous shale interbeded with silty shale or muddy siltstone developed in deep or semi-deep lake. In the late expansion system tract, argillaceous shale is widely deposited in the deepest depression, calcareous shale presented band distribution in the east of the depression. Actual test results indicate that these methods are feasible to predict the spatial distribution of shale lithofacies.

  18. Turnover of intra- and extra-aggregate organic matter at the silt-size scale

    Science.gov (United States)

    I. Virto; C. Moni; C. Swanston; C. Chenu

    2010-01-01

    Temperate silty soils are especially sensitive to organic matter losses associated to some agricultural management systems. Long-term preservation of organic C in these soils has been demonstrated to occur mainly in the silt- and clay-size fractions, although our knowledge about the mechanisms through which it happens remains unclear. Although organic matter in such...

  19. productivity of maize hybrid maturity classes in savanna agro

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    11, ... it requires fertile, well-drained loam soil, well- ... This was equivalent to 320 g per ... Agronomic characteristics of hybrid varieties of maize used in the field experiment in ... moisture content, at which figure it is believed to ..... Textural class.

  20. Efficient recovery of environmental DNA for expression cloning by indirect extraction methods

    NARCIS (Netherlands)

    Gabor, Esther; de Vries, Erik; Janssen, DB

    2003-01-01

    Using direct and cell extraction-based (indirect) isolation methods, DNA was obtained from environmental samples with largely differing characteristics (loam soil, sand soil, sediment, activated sludge, and compost) and evaluated with respect to the comprised bacterial diversity and its suitability

  1. Management of parthenium weed by extracts and residue of wheat

    African Journals Online (AJOL)

    Ehsan Zaidi

    2011-10-24

    Oct 24, 2011 ... bioassay, dried and chopped wheat straw of the four test wheat varieties was thoroughly mixed in pot ... environment from living plants and the subsequent ... Copped materials were mixed in sandy loam soil in plastic pots of 8.

  2. Estimating Infiltration Rates for a Loessal Silt Loam Using Soil Properties

    Science.gov (United States)

    M. Dean Knighton

    1978-01-01

    Soil properties were related to infiltration rates as measured by single-ringsteady-head infiltometers. The properties showing strong simple correlations were identified. Regression models were developed to estimate infiltration rate from several soil properties. The best model gave fair agreement to measured rates at another location.

  3. Short exposure to acetylene to distinguish between nitrifier and denitrifier nitrous oxide production in soil and sediment samples

    NARCIS (Netherlands)

    Kester, R.A.; Boer, W. de; Laanbroek, H.J.

    1996-01-01

    The contribution of nitrifiers and denitrifiers to the nitrous oxide production in slurries of calcareous silt loam and river bank sediment at different oxygen concentrations was determined using acetylene as nitrification inhibitor. The addition of 10 Pa acetylene resulted in inhibition of

  4. Short exposure to acetylene to distinguish between nitrifier and denitrifier nitrous oxide production in soil and sediment samples

    NARCIS (Netherlands)

    Kester, R.A.; De Boer, W.; Laanbroek, H.J.

    1996-01-01

    The contribution of nitrifiers and denitrifiers to the nitrous oxide production in slurries of calcareous silt loam and river bank sediment at different oxygen concentrations was determined using acetylene as nitrification inhibitor. The addition of 10 Pa acetylene resulted in inhibition of nitrous

  5. Investigation of plutonium behaviour in artificially contaminated soil

    International Nuclear Information System (INIS)

    Lukshiene, B.; Druteikiene, R.

    2006-01-01

    The vertical migration and transformation of plutonium chemical forms artificially supplied to sandy loam columns after its exposure to natural conditions for about one year was investigated. An analysis of artificially contaminated samples after one year had shown that 81% of 239 Pu 4+ and 44% of 239 Pu 3+ were accumulated in the 0-5 cm layer of sandy loam. The data of sequential analysis of the same type of soil at the adequate artificial contamination level after one month exposure under laboratory conditions are presented as well. Pu 239 binding to soil geochemical fractions was rather uneven. The largest amount of Pu 239 (60 %) was determined in the residual fraction. Consequently, it can be assumed that organic substances and some inorganic compounds, which usually are the main components of a residual fraction, affects the retention and migration of plutonium in the soil. (authors)

  6. Investigation of plutonium behaviour in artificially contaminated soil

    International Nuclear Information System (INIS)

    Luksiene, B.; Druteikiene, R.

    2006-01-01

    The vertical migration and transformation of plutonium chemical forms artificially supplied to sandy loam columns after its exposure to natural conditions for about one year was investigated. An analysis of artificially contaminated samples after one year had shown that 81% of 239 Pu 4+ and 44% of 239 Pu 3+ were accumulated in the 0-5 cm layer of sandy loam. The data of sequential analysis of the same type of soil at the adequate artificial contamination level after one month exposure under laboratory conditions are presented as well. Pu 239 binding to soil geochemical fractions was rather uneven. The largest amount of Pu 239 (60%) was determined in the residual fraction. Consequently, it can be assumed that organic substances and some inorganic compounds, which usually are the main components of a residual fraction, affects the retention and migration of plutonium in the soil. (authors)

  7. The fate of uranium contaminants of phosphate fertiliser: chemical partitioning of uranium in two New Zealand soils of volcanic origin and the effect on partitioning of amending one of those soils with uranium

    International Nuclear Information System (INIS)

    Taylor, M.D.

    1998-01-01

    This study assessed the chemical partitioning of U isotopes in Horomanga Sandy Loam and Te Kowhai silt loam, two agricultural soils derived from rhyolitic ash and receiving low level contamination from U impurities in phosphate fertiliser. To simulate future U additions, a sub-sample of the Horomanga soil was amended with 2.259 μg U g -1 soil before sequential extraction. The hypothesis that U additions will be strongly held on to the soil and are not available for leaching or plant uptake was tested. After extraction U was purified and determined by alpha spectrometry. Results were corrected for tailing, background, for losses in the purification process (using 232 U), and for soil moisture. It is concluded that only a small proportion of U in the two type of soils examined was derived from fertiliser and that very little U would be available to plants or to leaching

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

    Science.gov (United States)

    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%.

  9. Interaction of different irrigation strategies and soil textures on the nitrogen uptake of field grown potatoes

    DEFF Research Database (Denmark)

    Ahmadi, S.H.; Andersen, Mathias Neumann; Lærke, Poul Erik

    2011-01-01

    Nitrogen (N) uptake (kg ha-1) of field-grown potatoes was measured in 4.32 m2 lysimeters that were filled with coarse sand, loamy sand, and sandy loam and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation strategies. PRD and DI as water-saving irrigation treatments...... in the loamy sand had the highest amount of N uptake. The interaction between irrigation treatments and soil textures was significant, and implied that under non-limiting water conditions, loamy sand is the suitable soil for potato production because plants can take up sufficient amounts of N and it could...... potentially lead to higher yield. However, under limited water conditions and applying water-saving irrigation strategies, sandy loam and coarse sand are better growth media because N is more available for the potatoes. The simple yield prediction model was developed that could explains ca. 96...

  10. Effects of irrigation strategies and soils on field grown potatoes

    DEFF Research Database (Denmark)

    Ahmadi, Seyed Hamid; Plauborg, Finn; Andersen, Mathias Neumann

    2011-01-01

    Root distribution of field grown potatoes (cv. Folva) was studied in 4.32m2 lysimeters and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation strategies. Drip irrigation was applied for all irrigations. Irrigations were run in three different soils: coarse sand......, loamy sand, and sandy loam. Irrigation treatments started after tuber bulking and lasted until final harvest with PRD and DI receiving 65% of FI. Potatoes irrigated with water-saving irrigation techniques (PRD and DI) did not show statistically different dry root mass and root length density (RLD, cm...... density in the furrow. Most roots accumulated in the surface layers of coarse sand as compared to the other soil types. In the deep soil profile (30–70 cm) a higher root density was found in loamy sand compared with the sandy loam and coarse sand. Approximately twice the amounts of roots were found below...

  11. Land surface evapotranspiration modelling at the regional scale

    Science.gov (United States)

    Raffelli, Giulia; Ferraris, Stefano; Canone, Davide; Previati, Maurizio; Gisolo, Davide; Provenzale, Antonello

    2017-04-01

    minimal point of soil moisture that plant requires not to wilt); the field capacity (i.e. the maximum amount of water content that a soil can held); the available water content (AWC), obtained as the difference between field capacity and wilting point. Furthermore, the model considers 15 different ID of land use, with a resolution of 250 m. The model was then tested by a direct comparison with experimental data. First, the modelled water content from the surface down to 65 cm of soil depth was compared to the measured one with a Time Domain Reflectometry (TDR) in Grugliasco (TO), a non-irrigated flat permanent meadow, for years 2006-2008. Here, the soil is sandy with a slope of about 1%. Then, considering three corn farms located in the Cuneo district, the goodness of modelled irrigations was verified. The soil texture of the three farms, analysed according to the USDA criteria, is loam or silty-loam. In particular, we compared the number of irrigations done by the farmers with the ones given by the model, which irrigates as soon as the plant reaches an imposed level of water stress. We also compared the irrigation turn given by the model with the farmers' one. Then we compared the modelled water content with the one measured before and after the irrigation. We observed that the modelled irrigation occurred when the measured water content was close to the modelled wilting point. In both test cases, the model seems to reflect quite well the real behaviour of water content.

  12. Transport of contaminants from energy-process-waste leachates through subsurface soils and soil components: laboratory experiments

    International Nuclear Information System (INIS)

    Wangen, L.E.; Stallings, E.A.; Walker, R.D.

    1982-08-01

    The subsurface transport and attenuation of inorganic contaminants common to a variety of energy process waste leachates are being studied using laboratory column methods. Anionic species currently being emphasized are As, B, Mo, and Se. Transport of the cations Cd and Ni is also being studied. The solid adsorbents consist of three soil mineral components (silica sand, kaolinite, and goethite), and four subsurface soils (a dunal sand, an oxidic sandy clay loam, an acidic clay loam, and an alkaline clay loam). Breakthrough patterns of these species from packed soil columns are followed by monitoring eluent concentrations vs time under carefully controlled laboratory conditions. This report describes the experimental methods being used, the results of preliminary batch adsorption studies, and the results of column experiments completed through calendar year 1981. Using column influent concentrations of about 10 mg/l, adsorption (mmoles/100 g) has been determined from the eluent volume corresponding to 50% breakthrough. On silica sand, kaolinite, dunal sand, and goethite, respectively, these are 2.0 x 10 -4 , 0.020, 0.013, and 0.31 for cadmium, 4.4 x 10 -4 , 0.039, 0.020, and 0.98 for nickel. On kaolinite, dunal sand, and goethite, respectively, adsorption values (mmoles/100 g) are As (0.24, 0.019, and 20.5), B (0.041, 0.0019, and 1.77), Mo (0.048, 0.0010, and 5.93), and Se (0.029, 0.00048, and 1.30). Arsenic is the most highly adsorbed contaminant species and goethite has the largest adsorption capacity of the adsorbents

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

    Science.gov (United States)

    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.

  14. Study on weathering index for improving the reliability of terrace correlation and chronology. Based on the observation and analysis of terrace deposit distributed in the Mid Niigata region and others

    International Nuclear Information System (INIS)

    Hamada, Takaomi; Hataya, Ryuta

    2009-01-01

    We carried out field survey and laboratory analysis to investigate various weathering indexes in loam and terrace deposit at outcrops of the terraces distributed in Mid-Niigata area and other two areas, which were correlated and chronologized accurately. We also collect and analyze the data of color and hardness of eolian loam, matrix of terrace deposit, thickness of decolorated and/or browning rim of terrace gravels, color and roughness of gravel surface and effective porosity on each terrace. According to result of the analysis, thickness of weathering rind can be an useful index for terrace correlation. Weathering rind is observed frequently in mafic and fine gravels, as a result of statistical survey of occurrence of the patterns of weathering type. According to the result of our field survey, Middle terrace contains few decayed gravels and Higher terrace group, which is older than MIS8 terrace, contains large amounts of decayed gravels. We can distinguish two different age terraces according to ratio of decayed gravel concentration in terrace deposit. Combination of data of thickness of weathering rind of gravel and concentration of decayed gravel in terrace deposit, adequate terrace correlation can be obtained with increased reliability. Difference of weathering degree can be detected by a combination of several indexes that can be observed in outcrops, it is possible to distinguish between different age terraces. Color and hardness of loam, thickness of weathering rind of terrace gravel can be indexes of weathering, these can explain the facts observed in outcrops. (author)

  15. Recycled Urban Wastewater for Irrigation of Jatropha curcas L. in Abandoned Agricultural Arid Land

    Directory of Open Access Journals (Sweden)

    María Dorta-Santos

    2014-10-01

    Full Text Available In a global context in which obtaining new energy sources is of paramount importance, the production of biodiesel from plant crops is a potentially viable alternative to the use of fossil fuels. Among the species used to produce the raw material for biodiesel, Jatropha curcas L. (JCL has enjoyed increased popularity in recent years, due partly to its ability to grow in degraded zones and under arid and semi-arid conditions. The present study evaluates the potential for JCL production under irrigation with non-conventional water resources in abandoned agricultural soils of the island of Fuerteventura (Canary Islands, Spain, which is one of the most arid parts of the European Union. JCL growth and productivity are compared during the first 39 months of cultivation in two soil types (clay-loam and sandy-loam and with two irrigation water qualities: recycled urban wastewater (RWW and desalinated brackish water (DBW. The results indicate that JCL growth (in terms of plant height and stem diameter was significantly influenced both by soil type and water quality, with better development observed in the sandy-loam soil under RWW irrigation. Productivity, measured as cumulative seed production, was not affected by soil type but was affected by water quality. Production under RWW irrigation was approximately seven times greater than with DBW (mean ~2142 vs. 322 kg·ha−1. The higher nutrient content, especially P, K and Mg, and lower B content of the RWW were found to be key factors in the greater productivity observed under irrigation with this type of water.

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

    Science.gov (United States)

    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.

  17. Evaporation From Soil Containers With Irregular Shapes

    Science.gov (United States)

    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.

  18. Rheological properties of different minerals and clay soils

    Directory of Open Access Journals (Sweden)

    Dolgor Khaydapova

    2015-07-01

    Full Text Available Rheological properties of kaolinite, montmorillonite, ferralitic soil of the humid subtropics (Norfolk island, southwest of Oceania, alluvial clay soil of arid subtropics (Konyaprovince, Turkey and carbonate loess loam of Russian forest-steppe zone were determined. A parallel plate rheometer MCR-302 (Anton Paar, Austria was used in order to conduct amplitude sweep test. Rheological properties allow to assess quantitatively structural bonds and estimate structural resistance to a mechanical impact. Measurements were carried out on samples previously pounded and capillary humidified during 24 hours. In the amplitude sweep method an analyzed sample was placed between two plates. The upper plate makes oscillating motions with gradually extending amplitude. Software of the device allows to receive several rheological parameters such as elastic modulus (G’, Pa, viscosity modulus (G", Pa, linear viscoelasticity range (G’>>G”, and point of destruction of structure at which the elastic modulus becomes equal to the viscosity modulus (G’=G”- crossover. It was found out that in the elastic behavior at G '>> G " strength of structural links of kaolinite, alluvial clay soil and loess loam constituted one order of 105 Pa. Montmorillonit had a minimum strength - 104 Pa and ferrallitic soil of Norfolk island [has] - a maximum one -106 Pa. At the same time montmorillonite and ferralitic soil were characterized by the greatest plasticity. Destruction of their structure (G '= G" took place only in the cases when strain was reaching 11-12%. Destraction of the kaolinite structure happened at 5% of deformation and of the alluvial clay soil and loess loam - at 4.5%.

  19. Chemical composition of Kiscellian silty sediment (sivica from the Trobni Dol area, Eastern Slovenia

    Directory of Open Access Journals (Sweden)

    Miha Mišič

    2003-06-01

    Full Text Available Kiscellian marine silt termed »sivica« is widely developed in Tertiary basins of Eastern Slovenia. Chemical composition is rather uniform and reflects the dominance of filosilicates (mainly illite/muscovite, chlorite and montmorillonite and carbonates. PAAS normalised REE and Y abundances are slightly depleted for La, Ce, Pr and Nd, very close to PAAS for Sm, Eu, Gd and Tb, and depleted for Y, Ho, Er, Tm, Yb and Lu.

  20. Influence of Rice Husk Ash and Clay in Stabilization of Silty Soils Using Cement

    Directory of Open Access Journals (Sweden)

    Widjajakusuma Jack

    2017-01-01

    Full Text Available Soil stabilization is needed to enhance the strength of the soil. One popular method of soil stabilization is using cement. Due to the environmental issue, it is a need to reduce the application of cement and/or to replace partially the cement with other environmental-friendly compounds. One of these compounds is rice husk ash (RSA, which is agricultural wastes. The objective of this paper is to study the influence of RSA and clay as partial replacement to cement in soil stabilization of silt soil with high plasticity (MH using cement. The cement used was ordinary Portland cement, while the RHA was obtained by burning rice husk at temperature of 250°C. The MH soil is stabilized with 4% cement, 4% cement and 3% rice husk ash and 4% cement, 3 % RHA and 3 % clay. The various tests were conducted on the pure and stabilized soils. Results have indicated that application of 4% cement, 3 % RHA and 3 % clay as silt soil stabilization is more favorable in increasing soil strength and reducing brittle behaviour of soil.

  1. Influence of Rice Husk Ash and Clay in Stabilization of Silty Soils Using Cement

    OpenAIRE

    Widjajakusuma Jack; Winata Hendo

    2017-01-01

    Soil stabilization is needed to enhance the strength of the soil. One popular method of soil stabilization is using cement. Due to the environmental issue, it is a need to reduce the application of cement and/or to replace partially the cement with other environmental-friendly compounds. One of these compounds is rice husk ash (RSA), which is agricultural wastes. The objective of this paper is to study the influence of RSA and clay as partial replacement to cement in soil stabilization of sil...

  2. Modelling the carbon cycle of grassland in the Netherlands under various management strategies and environmental conditions.

    NARCIS (Netherlands)

    Pol-van Dasselaar, van den A.; Lantinga, E.A.

    1995-01-01

    A simulation model of the grassland carbon cycle (CCGRASS) was developed to evaluate the long-term effects of different management strategies and various environmental conditions on carbon sequestration in a loam soil under permanent grassland in the Netherlands. The model predicted that the rate of

  3. Effects Of Palm Oil Mill Effluents (Pome) On Soil Bacterial Flora And ...

    African Journals Online (AJOL)

    Sandy loam soil in Egbema, Rivers State was impacted with POME at different levels and analyzed for bacteriological quality and soil enzyme activities. Light application caused significant increase in total heterotrophic, phosphate solibilizing, nitrifying and lipolytic bacterial counts while heavy application caused a decrease ...

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

    Science.gov (United States)

    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...

  5. Soil microbial and physical properties and their relations along a steep copper gradient

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Møldrup, Per; Holmstrup, Martin

    2012-01-01

    years; from background concentrations up to 3837 mg Cu kg–1) on soil microbial enzyme activity, physical properties and resilience to compression. Soil samples and cores were taken from a fallow sandy loam field in Denmark. Microbial activity was quantified using fluorescein diacetate (FDA...

  6. Improvement, Verification, and Refinement of Spatially-Explicit Exposure Models in Risk Assessment - SEEM

    Science.gov (United States)

    2015-06-01

    is Beltsville silt loam. Land use in the watershed is mainly upland or wetland forests, with significant urban and agricultural development. The...covered with extensive woodlands and wetlands that provide habitat for many animals, including white tail deer, foxes, and wild turkeys. The area is

  7. Improvement, Verification, and Refinement of Spatially Explicit Exposure Models in Risk Assessment - SEEM Demonstration

    Science.gov (United States)

    2015-06-01

    is Beltsville silt loam. Land use in the watershed is mainly upland or wetland forests, with significant urban and agricultural development. The...covered with extensive woodlands and wetlands that provide habitat for many animals, including white tail deer, foxes, and wild turkeys. The area is

  8. Effects of litter quality and parent material on organic matter characteristics and N-dynamics in Luxembourg beech and hornbeam forests

    NARCIS (Netherlands)

    Kooijman, A.M.; Martinez-Hernandez, G.B.

    2009-01-01

    To test effects of litter quality and soil conditions on N-dynamics, we selected seven forests in Luxembourg dominated by beech (Fagus sylvatica, L.) and hornbeam (Carpinus betulus L.), and located on acid loam, decalcified marl or limestone, and measured organic matter characteristics, microbial C

  9. High-Explosive Cratering a Frozen and Unfrozen Soils in Alaska

    Science.gov (United States)

    1980-02-01

    SAMPLES I DEPTH TO .... T 24 DATE HOLEIROUN - S]T AR ED adO~ ________ F __24_ad_2____________7 EL . ITHOE (4IQ1 ~.0oioy Section ChlofRrndotboelI a...MotorIoI. Bronco Dno 20 f t.D. FREDRICKSON DEPTH %WATER SAI.IPLE SOIL MAAX FEET .4CtENT NO LEGEND CLASSIFICATION IZE F G i Silty Sandy Gravel Brown, Frozen

  10. Preliminary Evaluation of Some Engineering Geological Properties ...

    African Journals Online (AJOL)

    BH 2 to BH 10 present single to two layered stratigraphy of the commonly occurring fine sand and silty clay in various thicknesses to the maximum drilled depth of 10m. Grain size analysis results show a range of poorly graded (well sorted) sands with uniform gradation curves and very little or no fines (0.08 to 6.56% passing ...

  11. In-Situ Spatial Variability Of Thermal Conductivity And Volumetric ...

    African Journals Online (AJOL)

    Studies of spatial variability of thermal conductivity and volumetric water content of silty topsoil were conduct-ed on a 0.6 ha site at Abeokuta, South-Western Nigeria. The thermal conductivity (k) was measured at depths of up to 0.06 m along four parallel profiles of 200 m long and at an average temperature of 25 C, using ...

  12. Growth and physiological aspects of bell pepper ( Capsicum annuum )

    African Journals Online (AJOL)

    This study aimed to evaluate growth and physiological aspects of 'All Big' bell pepper, under saline stress and exogenous application of proline on the leaves. The research was conducted in pots adapted as drainage lysimeters under greenhouse conditions, using sandy-loam eutrophic Regolithic Neosol, in the ...

  13. The impact of the age of vines on soil hydraulic conductivity in vineyards in eastern Spain

    NARCIS (Netherlands)

    Alagna, Vincenzo; Prima, Di Simone; Rodrigo-Comino, Jesús; Iovino, Massimo; Pirastru, Mario; Keesstra, Saskia D.; Novara, Agata; Cerdà, Artemio

    2017-01-01

    Soil infiltration processes manage runoff generation, which in turn affects soil erosion. There is limited information on infiltration rates. In this study, the impact of vine age on soil bulk density (BD) and hydraulic conductivity (Ks) was assessed on a loam soil tilled by chisel plough. Soil

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

    Science.gov (United States)

    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...

  15. Fine-scale spatial distribution of plants and resources on a sandy soil in the Sahel

    NARCIS (Netherlands)

    Rietkerk, M.G.; Ouedraogo, T.; Kumar, L.; Sanou, S.; Langevelde, F. van; Kiema, A.; Koppel, J. van de; Andel, J. van; Hearne, J.; Skidmore, A.K.; Ridder, N. de; Stroosnijder, L.; Prins, H.H.T.

    2002-01-01

    We studied fine-scale spatial plant distribution in relation to the spatial distribution of erodible soil particles, organic matter, nutrients and soil water on a sandy to sandy loam soil in the Sahel. We hypothesized that the distribution of annual plants would be highly spatially autocorrelated

  16. Wind erosion potential of a winter wheat–summer fallow rotation after land application of biosolids

    Science.gov (United States)

    While land application of biosolids is recognized as a sustainable management practice for enhancing soil health, no studies have determined the effects of biosolids on soil wind erosion. Wind erosion potential of a silt loam was assessed using a portable wind tunnel after applying synthetic and bio...

  17. Performance of Two Bioswales on Urban Runoff Management

    Directory of Open Access Journals (Sweden)

    Qingfu Xiao

    2017-09-01

    Full Text Available This study evaluated the effectiveness of two bioswales eight years after construction in Davis, California. The treatment bioswale measured 9 m × 1 m × 1 m (L × W × D. Engineered soil mix (75% native lava rock and 25% loam soil replaced the native loam soil. Four Red Tip Photinia (Photinia × fraseri Dress trees and two Blueberry Muffin Hawthorn (Rhaphiolepis umbellata (Thunb. Makino shrubs were planted in the bioswale. Runoff flowed into the bioswale from an adjacent 171 m2 panel of turf grass. An identically sized control bioswale consisting of non-disturbed native soil was located adjacent to the treatment bioswale. Surface runoff quantity and quality were measured during three experiments with different pollutant loads. When compared to the control, the treatment bioswale reduced surface runoff by 99.4%, and reduced nitrogen, phosphate, and total organic carbon loading by 99.1%, 99.5%, and 99.4%, respectively. After eight years, tree growth characteristics were similar across both sites.

  18. Adsorption behavior of endosulfan on alluvial soil

    International Nuclear Information System (INIS)

    Ashraf, M.; Sherazi, S.T.H.; Nizamani, S.M.; Bhanger, M.I.

    2012-01-01

    The present study was carried out to assess the behavior of endosulfan pesticide in alluvial soil under laboratory conditions. Sandy loam soil was studied to evaluate the fate of applied endosulfan with respect to soil properties. Known amount of endosulfan was added on alluvial soil in PVC column and eluted with 1000 ml of water. Eluents were collected in 10 parts, each of 100 ml. The soil in the column was divided in to three equal parts, each of 10 cm. Each part of the soil and eluents were analyzed for the determination of Endosulfan level using GC- mu ECD and GC-MS techniques. The kinetic and equilibrium adsorption characteristics of endosulfan on sandy loam soil was also studied and found that it follows Ho's pseudo second order and Freundlich isotherm. The present study revealed that a-and beta-Endosulfan was determined efficiently with their degraded products in alluvial soil under laboratory conditions with above mentioned instruments. (author)

  19. Study on Soil Mobility of Two Neonicotinoid Insecticides

    Directory of Open Access Journals (Sweden)

    Mária Mörtl

    2016-01-01

    Full Text Available Movement of two neonicotinoid insecticide active ingredients, clothianidin (CLO and thiamethoxam (TMX, was investigated in different soil types (sand, clay, or loam and in pumice. Elution profiles were determined to explore differences in binding capacity. Soil characterized by high organic matter content retained the ingredients, whereas high clay content resulted in long release of compounds. Decrease in concentration was strongly influenced by soil types: both CLO and TMX were retained in loam and clay soils and showed ready elution through sandy soil and pumice. Elution capability of the active ingredients in sandy soil correlated with their water solubility, indicating approximately 30% higher rapidity for TMX than for CLO. Soil organic carbon-water partitioning coefficients (Koc determined were in good agreement with literature values with somewhat lower value for CLO in sandy soil and substantially higher values for TMX in clay soil. High mobility of these neonicotinoid active ingredients in given soil types urges stronger precautionary approach taken during their application.

  20. Fate of fertilizer nitrogen in flooded rice soil - I. Leaching losses of nitrogen

    International Nuclear Information System (INIS)

    Daftardar, S.Y.; Deb, D.L.; Datta, N.P.

    1979-01-01

    A greenhouse experiment on rice (Oryza sativa L. cv IR 22) was conducted under flooded conditions using CO( 15 NH 2 ) 2 , 15 NH 4 NO 3 and NH 4 ( 15 NO 3 ) to study the leaching loss of added fertilizer nitrogen in two typical rice soils. The loss of nitrogen was in the order: NO 3 -N (4 to 25.6 percent) > amide-N (1.2 to 16.2 percent) > NH 4 -N (0.07 to 0.3 percent). The basal applied urea was lost by percolation in the first month while the basal applied NO 3 -N was lost in the first 8 days. Leaching loss did not occur after split application of fertilizer nitrogen at primordial initiation stage. The loss of nitrogen in kaolinitic Dapoli clay loam soil was about 2.5 to 4.5 times more than that in montmorillonitic Karjat sandy loam soil. Cropping reduced the percolation loss of N by 40 to 60 percent. (auth.)