Environmental Chemistry Methods (ECM) Index - K

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with K as the first character.

Environmental Chemistry Methods (ECM) Index - R

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with R as the first character.

Environmental Chemistry Methods (ECM) Index - G

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with G as the first character.

Environmental Chemistry Methods (ECM) Index - F

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with F as the first character.

Environmental Chemistry Methods (ECM) Index - B

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with B as the first character.

Environmental Chemistry Methods (ECM) Index - M

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with M as the first character.

Environmental Chemistry Methods (ECM) Index - C

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with C as the first character.

Environmental Chemistry Methods (ECM) Index - H

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with H as the first character.

Environmental Chemistry Methods (ECM) Index - 0-9

EPA Pesticide Factsheets

Laboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with a number as the first character.

Childhood lead poisoning investigations: evaluating a portable instrument for testing soil lead.

PubMed

Reames, Ginger; Lance, Larrie L

2002-04-01

The Childhood Lead Poisoning Prevention Branch of the California Department of Health Services evaluated a portable X-ray fluorescence (XRF) instrument for use as a soil lead-testing tool during environmental investigations of lead-poisoned children's homes. A Niton XRF was used to test soil at 119 sampling locations in the yards of 11 San Francisco Bay Area houses. Niton XRF readings were highly correlated with laboratory results and met the study criteria for an acceptable screening method. The data suggest that the most health-protective and time-efficient approach to testing for soil lead above regulatory levels is to take either surface readings or readings of a test cup of soil prepared by grinding with a mortar and pestle. The advantage of the test cup method is that the test cup with soil may be submitted to a laboratory for confirmatory analysis.

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

Stephenson, G.L.; Scroggins, R.

Environment Canada has embarked on a five year program to develop, standardize, and validate a battery of soil toxicity tests which can be used to assess the relative toxicity of contaminants in soils to terrestrial organisms. These tests must be applicable to soil conditions typically found in Canadian environments and the test species must be representative of the species of soil invertebrates or plants inhabiting soil ecosystems in Canada. One of the toxicity tests being developed is designed to assess the toxicity of contaminated soils to earthworms. Five of the potential test species belong to the Lumbricidae family and includemore » the Canadian worm (Allobophora calignosa/Aporrectodea tuberculate), the European bark worm (Dendrodtilus rubidus (rubida)), the pink soil worm (Eisenia rosea), the red marsh worm (Lumbricus rubellus), and the Canadian night crawler or dew worm (Lumbricus terrestris). The sixth species, the white pot worm (Enchytraeus albidus), belongs to the Enchytraeidae family. Further assessment reduced the number of representative species to three. Most earthworm test methods have been developed to assess the toxicity of chemically-spiked artificial soils to Eisenia fetida or E. andrei. Test methods have also been developed to assess the relative toxicity of contaminated soils from hazardous waste sites. Comparative acute toxicity data for three species of earthworm exposed to a hydrocarbon contamination will be presented. Comparative toxicity data for the same three species of earthworm will also be presented using test procedures and conditions that have been modified to accommodate biological differences among the species of earthworm. Recommendations regarding test design, methods, and conditions optimal for each test species will be summarized and discussed with respect to the precision of test results.« less

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

PubMed

Briassoulis, D; Mistriotis, A

2018-09-01

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

An efficient and reproducible method for improving growth of a soil alga (Chlorococcum infusionum) for toxicity assays.

PubMed

Nam, Sun-Hwa; An, Youn-Joo

2015-12-01

This study evaluated five methods of soil inoculation using the soil alga Chlorococcum infusionum to determine the most efficient and reproducible method for promoting the growth of soil algae for toxicity testing. The five techniques included application of C. infusionum in a circle on top of the soil, to a central spot on top of the soil, to a central spot in the subsoil, to one side on top of the soil, and application divided between a circle and a central spot on top of the soil. Of these, the first method generated the greatest amount of chlorophyll fluorescence and was the method with the best reproducibility. We evaluated the applicability of this method in an assessment of the toxicity of copper and nickel to C. infusionum in two representative standard soils. Copper (20-75 mg/kg for OECD soil and 20-60 mg/kg Lufa 2.2 soil) and nickel (400-500 mg/kg for OECD soil and 60-100 mg/kg Lufa 2.2 soil) reduced the chlorophyll fluorescence of C. infusionum when the inoculation was delivered in a circle on top of both soil types. To our knowledge, this is the first study to assess the suitability of different soil algal inoculation methods for terrestrial toxicity testing. Copyright © 2015 Elsevier B.V. All rights reserved.

ECM for Aldicarb & Degradates in Water - MRID 49515901

EPA Pesticide Factsheets

aboratories use testing methods to identify pesticides in water and soil. Environmental chemistry methods test soil and water samples to determine the fate of pesticides in the environment. Find methods for chemicals with A as the first character.

Characterization studies and indicated remediation methods for plutonium contaminated soils at the Nevada Test Site

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

Murarik, T.M.; Wenstrand, T.K.; Rogers, L.A.

An initial soil characterization study was conducted to help identify possible remediation methods to remove plutonium from the Nevada Test Site and Tonapah Test Range surface soils. Results from soil samples collected across various isopleths at five sites indicate that the size-fraction distribution patterns of plutonium remain similar to findings from the Nevada Applied Ecology Group (NAEG) (1970's). The plutonium remains in the upper 10--15 cm of soils, as indicated in previous studies. Distribution of fine particles downwind'' of ground zero at each site is suggested. Whether this pattern was established immediately after each explosion or this resulted from post-shotmore » wind movement of deposited material is unclear. Several possible soil treatment scenarios are presented. Removal of plutonium from certain size fractions of the soils would alleviate the sites of much of the plutonium burden. However, the nature of association of plutonium with soil components will determine which remediation methods will most likely succeed.« less

Characterization studies and indicated remediation methods for plutonium contaminated soils at the Nevada Test Site

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

Murarik, T.M.; Wenstrand, T.K.; Rogers, L.A.

An initial soil characterization study was conducted to help identify possible remediation methods to remove plutonium from the Nevada Test Site and Tonapah Test Range surface soils. Results from soil samples collected across various isopleths at five sites indicate that the size-fraction distribution patterns of plutonium remain similar to findings from the Nevada Applied Ecology Group (NAEG) (1970`s). The plutonium remains in the upper 10--15 cm of soils, as indicated in previous studies. Distribution of fine particles ``downwind`` of ground zero at each site is suggested. Whether this pattern was established immediately after each explosion or this resulted from post-shotmore » wind movement of deposited material is unclear. Several possible soil treatment scenarios are presented. Removal of plutonium from certain size fractions of the soils would alleviate the sites of much of the plutonium burden. However, the nature of association of plutonium with soil components will determine which remediation methods will most likely succeed.« less

Testing single extraction methods and in vitro tests to assess the geochemical reactivity and human bioaccessibility of silver in urban soils amended with silver nanoparticles.

PubMed

Cruz, N; Rodrigues, S M; Tavares, D; Monteiro, R J R; Carvalho, L; Trindade, T; Duarte, A C; Pereira, E; Römkens, Paul F A M

2015-09-01

To assess if the geochemical reactivity and human bioaccessibility of silver nanoparticles (AgNPs) in soils can be determined by routine soil tests commonly applied to other metals in soil, colloidal Ag was introduced to five pots containing urban soils (equivalent to 6.8 mg Ag kg(-1) soil). Following a 45 days stabilization period, the geochemical reactivity was determined by extraction using 0.43 M and 2 M HNO3. The bioaccessibility of AgNPs was evaluated using the Simplified Bioaccessibility Extraction Test (SBET) the "Unified BARGE Method" (UBM), and two simulated lung fluids (modified Gamble's solution (MGS) and artificial lysosomal fluid (ALF)). The amount of Ag extracted by 0.43 M and 2 M HNO3 soil tests was <8% and <50%, respectively of the total amount of Ag added to soils suggesting that the reactivity of Ag present in the soil can be relatively low. The bioaccessibility of Ag as determined by the four in vitro tests ranged from 17% (ALF extraction) to 99% (SBET) indicating that almost all Ag can be released from soil due to specific interactions with the organic ligands present in the simulated body fluids. This study shows that to develop sound soil risk evaluations regarding soil contamination with AgNPs, aspects of Ag biochemistry need to be considered, particularly when linking commonly applied soil tests to human risk assessment. Copyright © 2015 Elsevier Ltd. All rights reserved.

The tolerance efficiency of Panicum maximum and Helianthus annuus in TNT-contaminated soil and nZVI-contaminated soil.

PubMed

Jiamjitrpanich, Waraporn; Parkpian, Preeda; Polprasert, Chongrak; Laurent, François; Kosanlavit, Rachain

2012-01-01

This study was designed to compare the initial method for phytoremediation involving germination and transplantation. The study was also to determine the tolerance efficiency of Panicum maximum (Purple guinea grass) and Helianthus annuus (Sunflower) in TNT-contaminated soil and nZVI-contaminated soil. It was found that the transplantation of Panicum maximum and Helianthus annuus was more suitable than germination as the initiate method of nano-phytoremediation potting test. The study also showed that Panicum maximum was more tolerance than Helianthus annuus in TNT and nZVI-contaminated soil. Therefore, Panicum maximum in the transplantation method should be selected as a hyperaccumulated plant for nano-phytoremediation potting tests. Maximum tolerance dosage of Panicum maximum to TNT-concentration soil was 320 mg/kg and nZVI-contaminated soil was 1000 mg/kg in the transplantation method.

Develop a new testing and evaluation protocol to assess flexbase performance using strength of soil binder.

DOT National Transportation Integrated Search

2008-01-01

This research involved a detailed laboratory study of a new test method for evaluating road base materials based on : the strength of the soil binder. In this test method, small test specimens (5.0in length and 0.75in square cross : section) of binde...

[Environmental Education Units.] Soil Sampling. Stream Profiles. Tree Watching. Plant Puzzles.

ERIC Educational Resources Information Center

Minneapolis Independent School District 275, Minn.

Five of these eleven units describe methods elementary school students can use when studying soil characteristics. Soil nitrogen and water holding capacity tests are included with two techniques for measuring soil pH. Survey methods for soil organisms are suggested. The remaining pamphlets describe diverse activities associated with field…

Use of laboratory geophysical and geotechnical investigation methods to characterize gypsum rich soils

NASA Astrophysics Data System (ADS)

Bhamidipati, Raghava A.

Gypsum rich soils are found in many parts of the world, particularly in arid and semi-arid regions. Most gypsum occurs in the form of evaporites, which are minerals that precipitate out of water due to a high rate of evaporation and a high mineral concentration. Gypsum rich soils make good foundation material under dry conditions but pose major engineering hazards when exposed to water. Gypsum acts as a weak cementing material and has a moderate solubility of about 2.5 g/liter. The dissolution of gypsum causes the soils to undergo unpredictable collapse settlement leading to severe structural damages. The damages incur heavy financial losses every year. The objective of this research was to use geophysical methods such as free-free resonant column testing and electrical resistivity testing to characterize gypsum rich soils based on the shear wave velocity and electrical resistivity values. The geophysical testing methods could provide quick, non-intrusive and cost-effective methodologies to screen sites known to contain gypsum deposits. Reconstituted specimens of ground gypsum and quartz sand were prepared in the laboratory with varying amounts of gypsum and tested. Additionally geotechnical tests such as direct shear strength tests and consolidation tests were conducted to estimate the shear strength parameters (drained friction angle and cohesion) and the collapse potential of the soils. The effect of gypsum content on the geophysical and geotechnical parameters of soil was of particular interest. It was found that gypsum content had an influence on the shear wave velocity but had minimal effect on electrical resistivity. The collapsibility and friction angle of the soil increased with increase in gypsum. The information derived from the geophysical and geotechnical tests was used to develop statistical design equations and correlations to estimate gypsum content and soil collapse potential.

Determination of bentazone, dichlorprop, and MCPA in different soils by sodium hydroxide extraction in combination with solid-phase preconcentration.

PubMed

Thorstensen, C W; Christiansen, A

2001-09-01

A method for the extraction of bentazone, dichlorprop, and MCPA in three selected Norwegian soils of different textures is described. Initially three different extraction methods were tested on one soil type. All methods gave recoveries >80% for the pesticide mixture, but extraction with sodium hydroxide in combination with solid-phase preconcentration was used for further recovery tests with soils of different properties spiked at four herbicide concentration levels (0.001-10 microg/g of wet soil). The method was rapid and easy and required a minimum of organic solvents. The recoveries were in the range of 82-109, 80-123, and 45-91% for the soils containing 1.4 (Hole), 2.5 (Kroer), and 37.8% (Froland) organic carbon, respectively. Limits of quantification using GC-MS were 0.0003 microg/g of wet soil for bentazone and 0.0001 microg/g of wet soil for both dichlorprop and MCPA.

An evaluation of the utility of four in situ test methods for transmission line foundation design

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

Mullen, W.G. Jr.

1991-01-01

This research examines four existing in-situ soil strength testing methods; standard penetration test (SPT), the cone penetrometer (CPT), the flat plate dilatometer (DMT), and the pressuremeter (PMT). Soils data were collected at eight separate sites using each of the devices. The test sites were chosen to mirror soil conditions encountered within the service territory of Virginia Power, the project sponsor. A total of 19 standard soil borings, 30 cone penetrometer soundings, 26 dilatometer soundings, and 33 pressuremeter tests were undertaken in residual, alluvial and marine clay soil conditions. The testing program was conducted with five areas of concern: (1) comparisonmore » of the penetration/stiffness data from the four tests, (2) comparison of values of undrained shear strength and angle of internal friction developed from each of the test methods, (3) determination if pressuremeter data can be correlated to and thereby developed from one of the more rapid tests, (4) comparison of indirect soil type identifications from the standard borings, (5) development of information on the relative effort required for each test. Comparison of the penetration resistance stiffness data produced useful correlations among the CPT and DMT, with the SPT data yielding more erratic results. Shear strength data was most consistent for the marine clay sites, while the CPT and DMT returned useful friction angle data in the alluvial sands. PMT data correlated well to both the CPT and DMT test results. Correlation of PMT results to the SPT was more erratic. Indirect soil identification from the CPT and DMT was fully adequate for transmission line foundation design purposes, and finally, useful comparative data on the relative testing time required for the four in-situ tests was developed.« less

Performance-based quality assurance/quality control (QA/QC) acceptance procedures for in-place soil testing phase 3.

DOT National Transportation Integrated Search

2015-01-01

One of the objectives of this study was to evaluate soil testing equipment based on its capability of measuring in-place stiffness or modulus values. : As design criteria transition from empirical to mechanistic-empirical, soil test methods and equip...

Multilaboratory evaluation of methods for detecting enteric viruses in soils.

PubMed Central

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

1991-01-01

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

Multilaboratory evaluation of methods for detecting enteric viruses in soils.

PubMed

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

1991-02-01

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

A MULTI-LABORATORY EVALUATION OF METHODS FOR DETECTING ENTERIC VIRUSES IN SOILS

EPA Science Inventory

Two candidate methods for the recovery and detection of viruses in soil were subjected to round robin comparative testing by members of the American Society for Testing and Materials D19:24:04:04 Subcommittee Task Group. Selection of the methods, designated “Berg” and “Goyal,” wa...

Evaluation of the Migration Capacity of Zn in the Soil–Plant System

NASA Astrophysics Data System (ADS)

Anisimov, V. S.; Anisimova, L. N.; Frigidova, L. M.; Dikarev, D. V.; Frigidov, R. A.; Korneev, Yu. N.; Sanzharov, A. I.; Arysheva, S. P.

2018-04-01

The mobility and migration capacity of Zn in the soil-plant system were studied in a series of pot experiments with barley as a test plant. The parameters of Zn accumulation depending on the metal concentrations in soils and soil solutions were estimated by soil and water culture methods. Experiments with barley in water culture were performed on a nutrient (soil) solution extracted from soddy-podzolic soil (Albic Retisol (Loamic, Ochric)) to which Zn2+ was added to reach working concentrations increasing from 0.07 to 430 μM. Different responses of barley plants to changes in the concentration of Zn in the studied soil were identified. Ranges of the corresponding concentrations in the soil and aboveground barley biomass were determined. Parameters of Zn accumulation by test plants were determined depending on the metal content in soddypodzolic soil and the soil solution. A new method was proposed for evaluating the buffer capacity of soils with respect to a heavy metal (Zn) using test plants (BCS(P)Zn). The method was used to evaluate the buffering capacity of loamy sandy soddy-podzolic soil. The considered methodological approach offers opportunities for using data obtained during the agroecological monitoring of agricultural lands with heavy metals (HMs), including the contents of exchangeable HMs and macroelements (C and Mg) in soils and concentrations of HMs and (Ca + Mg) in plants, in the calculation of the buffering capacity of the surveyed soils for HMs.

Implementation of centrifuge testing of expansive soils for pavement design.

DOT National Transportation Integrated Search

2017-03-01

The novel centrifuge-based method for testing of expansive soils from project 5-6048-01 was implemented into : use for the determination of the Potential Vertical Rise (PVR) of roadways that sit on expansive subgrades. The : centrifuge method was mod...

Soil-contact decay tests using small blocks : a procedural analysis

Treesearch

Rodney C. De Groot; James W. Evans; Paul G. Forsyth; Camille M. Freitag; Jeffrey J. Morrell

Much discussion has been held regarding the merits of laboratory decay tests compared with field tests to evaluate wood preservatives. In this study, procedural aspects of soil jar decay tests with 1 cm 3 blocks were critically examined. Differences among individual bottles were a major source of variation in this method. The reproducibility and sensitivity of the soil...

Influence of solid-liquid separation method parameters employed in soil leaching tests on apparent metal concentration.

PubMed

Imoto, Yukari; Yasutaka, Tetsuo; Someya, Masayuki; Higashino, Kazuo

2018-05-15

Soil leaching tests are commonly used to evaluate the leachability of hazardous materials, such as heavy metals, from the soil. Batch leaching tests often enhance soil colloidal mobility and may require solid-liquid separation procedures to remove excess soil particles. However, batch leaching test results depend on particles that can pass through a 0.45μm membrane filter and are influenced by test parameters such as centrifugal intensity and filtration volume per filter. To evaluate these parameters, we conducted batch leaching experiments using metal-contaminated soils and focused on the centrifugal intensity and filtration volume per filter used in solid-liquid separation methods currently employed in standard leaching tests. Our experiments showed that both centrifugal intensity and filtration volume per filter affected the reproducibility of batch leaching tests for some soil types. The results demonstrated that metal concentrations in the filtrates significantly differed according to the centrifugal intensity when it was 3000 g for 2h or less. Increased filtration volume per filter led to significant decreases in filtrate metal concentrations when filter cakes formed during filtration. Comparison of the filtration tests using 0.10 and 0.45μm membrane filters showed statistically significant differences in turbidity and metal concentration. These findings suggest that colloidal particles were not adequately removed from the extract and contributed substantially to the apparent metal concentrations in the leaching test of soil containing colloidal metals. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Field test and sensitivity analysis of a sensible heat balance method to determine ice contents

USDA-ARS?s Scientific Manuscript database

Soil ice content impacts winter vadose zone hydrology. It may be possible to estimate changes in soil ice content with a sensible heat balance (SHB) method, using measurements from heat pulse (HP) sensors. Feasibility of the SHB method is unknown because of difficulties in measuring soil thermal pro...

Improvements of the Profil Cultural Method for a better Low-tech Field Assessment of Soil Structure under no-till

NASA Astrophysics Data System (ADS)

Roger-Estrade, Jean; Boizard, Hubert; Peigné, Josephine; Sasal, Maria Carolina; Guimaraes, Rachel; Piron, Denis; Tomis, Vincent; Vian, Jean-François; Cadoux, Stephane; Ralisch, Ricardo; Filho, Tavares; Heddadj, Djilali; de Battista, Juan; Duparque, Annie

2016-04-01

In France, agronomists have studied the effects of cropping systems on soil structure, using a field method based on a visual description of soil structure. The "profil cultural" method (Manichon and Gautronneau, 1987) has been designed to perform a field diagnostic of the effects of tillage and compaction on soil structure dynamics. This method is of great use to agronomists improving crop management for a better preservation of soil structure. However, this method was developed and mainly used in conventional tillage systems, with ploughing. As several forms of reduced, minimum and no tillage systems are expanding in many parts of the world, it is necessary to re-evaluate the ability of this method to describe and interpret soil macrostructure in unploughed situations. In unploughed fields, soil structure dynamics of untilled layers is mainly driven by compaction and regeneration by natural agents (climatic conditions, root growth and macrofauna) and it is of major importance to evaluate the importance of these natural processes on soil structure regeneration. These concerns have led us to adapt the standard method and to propose amendments based on a series of field observations and experimental work in different situations of cropping systems, soil types and climatic conditions. We improved the description of crack type and we introduced an index of biological activity, based on the visual examination of clods. To test the improved method, a comparison with the reference method was carried out and the ability of the "profil cultural" method to make a diagnosis was tested on five experiments in France, Brazil and Argentina. Using the improved method, the impact of cropping systems on soil functioning was better assessed when natural processes were integrated into the description.

Deriving site-specific soil clean-up values for metals and metalloids: Rationale for including protection of soil microbial processes

PubMed Central

Kuperman, Roman G; Siciliano, Steven D; Römbke, Jörg; Oorts, Koen

2014-01-01

Although it is widely recognized that microorganisms are essential for sustaining soil fertility, structure, nutrient cycling, groundwater purification, and other soil functions, soil microbial toxicity data were excluded from the derivation of Ecological Soil Screening Levels (Eco-SSL) in the United States. Among the reasons for such exclusion were claims that microbial toxicity tests were too difficult to interpret because of the high variability of microbial responses, uncertainty regarding the relevance of the various endpoints, and functional redundancy. Since the release of the first draft of the Eco-SSL Guidance document by the US Environmental Protection Agency in 2003, soil microbial toxicity testing and its use in ecological risk assessments have substantially improved. A wide range of standardized and nonstandardized methods became available for testing chemical toxicity to microbial functions in soil. Regulatory frameworks in the European Union and Australia have successfully incorporated microbial toxicity data into the derivation of soil threshold concentrations for ecological risk assessments. This article provides the 3-part rationale for including soil microbial processes in the development of soil clean-up values (SCVs): 1) presenting a brief overview of relevant test methods for assessing microbial functions in soil, 2) examining data sets for Cu, Ni, Zn, and Mo that incorporated soil microbial toxicity data into regulatory frameworks, and 3) offering recommendations on how to integrate the best available science into the method development for deriving site-specific SCVs that account for bioavailability of metals and metalloids in soil. Although the primary focus of this article is on the development of the approach for deriving SCVs for metals and metalloids in the United States, the recommendations provided in this article may also be applicable in other jurisdictions that aim at developing ecological soil threshold values for protection of microbial processes in contaminated soils. PMID:24376192

Mobility of coated and uncoated TiO2 nanomaterials in soil columns--Applicability of the tests methods of OECD TG 312 and 106 for nanomaterials.

PubMed

Nickel, Carmen; Gabsch, Stephan; Hellack, Bryan; Nogowski, Andre; Babick, Frank; Stintz, Michael; Kuhlbusch, Thomas A J

2015-07-01

Nanomaterials are commonly used in everyday life products and during their life cycle they can be released into the environment. Soils and sediments are estimated as significant sinks for those nanomaterials. To investigate and assess the behaviour of nanomaterials in soils and sediments standardized test methods are needed. In this study the applicability of two existing international standardized test guidelines for the testing of nanomaterials, OECD TG 106 "Adsorption/Desorption using a Bath Equilibrium Method" and the OECD TG 312 "Leaching in Soil Columns", were investigated. For the study one coated and two uncoated TiO2 nanomaterials were used, respectively. The results indicate that the OECD TG 106 is not applicable for nanomaterials. However, the test method according to OECD TG 312 was found to be applicable if nano-specific adaptations are applied. The mobility investigations of the OECD TG 312 indicated a material-dependent mobility of the nanomaterials, which in some cases may lead to an accumulation in the upper soil layers. Whereas no significant transport was observed for the uncoated materials for the double-coated material (coating with dimethicone and aluminiumoxide) a significant transport was detected and attributed to the coating. Copyright © 2015 Elsevier Ltd. All rights reserved.

Basic Aspects of Deep Soil Mixing Technology Control

NASA Astrophysics Data System (ADS)

Egorova, Alexandra A.; Rybak, Jarosław; Stefaniuk, Damian; Zajączkowski, Przemysław

2017-10-01

Improving a soil is a process of increasing its physical/mechanical properties without changing its natural structure. Improvement of soil subbase is reached by means of the knitted materials, or other methods when strong connection between soil particles is established. The method of DSM (Deep Soil Mixing) columns has been invented in Japan in 1970s. The main reason of designing cement-soil columns is to improve properties of local soils (such as strength and stiffness) by mixing them with various cementing materials. Cement and calcium are the most commonly used binders. However new research undertaken worldwide proves that apart from these materials, also gypsum or fly ashes can also be successfully implemented. As the Deep Soil Mixing is still being under development, anticipating mechanical properties of columns in particular soils and the usage of cementing materials in formed columns is very difficult and often inappropriate to predict. That is why a research is carried out in order to find out what binders and mixing technology should be used. The paper presents several remarks on the testing procedures related to quality and capacity control of Deep Soil Mixing columns. Soil improvement methods, their advantages and limitations are briefly described. The authors analyse the suitability of selected testing methods on subsequent stages of design and execution of special foundations works. Chosen examples from engineering practice form the basis for recommendations for the control procedures. Presented case studies concerning testing the on capacity field samples and laboratory procedures on various categories of soil-cement samples were picked from R&D and consulting works offered by Wroclaw University of Science and Technology. Special emphasis is paid to climate conditions which may affect the availability of performing and controlling of DSM techniques in polar zones, with a special regard to sample curing.

Methodological Approaches toward Chemico-Biological Diagnostics of the State of Soils in Technogenically Transformed Territories

NASA Astrophysics Data System (ADS)

Fokina, A. I.; Dabakh, E. V.; Domracheva, L. I.; Skugoreva, S. G.; Lyalina, E. I.; Ashikhmina, T. Ya.; Zykova, Yu. N.; Leonova, K. A.

2018-05-01

The comprehensive diagnostics of the state of soils in the impact zone of thermal power station (TPS-5) in the city of Kirov was performed on the basis of the soil chemical analyses and the study of biota response to the loads at different organization levels. The chemical analyses attested to a satisfactory state of the soils. However, the use of soil cyanobacteria and bird's-foot trefoil ( Lótus corniculátus) as test objects showed the toxicity of studied soil samples. The toxicity of the samples was judged from the bioindication effects of cyanophytization and melanization of soil microbial complexes. The obtained results demonstrated that at relatively low concentrations of total and mobile heavy metal compounds in the soil samples, their amount released into the tested soil water (1: 4) extract exceeded the limit allowable for normal functioning of living organisms. For the first time, the express cyanobacterial tetrazole-topographic method of biotesting was applied in the geoecological study to estimate the toxicity of the soil samples. The results obtained with the help of traditional and express methods proved to be comparable. The express-method was sufficiently sensitive and efficient. It allowed the determination of the samples' toxicity in five hours, i.e., four to five times faster than the traditional technique. An inverse relationship between the number of viable cells of cyanobacteria (as judged from the inclusion of formazan crystals) and the concentration of lead ions in the tested soil extracts was found. This finding can be considered a prerequisite for further study and application of the express method in the practice of geoecological monitoring. Our study demonstrated the necessity of a comprehensive approach for the assessment of the real ecological state of soils in the investigated impact zone of the thermal power station.

A rapid method for soil cement design : Louisiana slope value method.

DOT National Transportation Integrated Search

1964-03-01

The current procedure used by the Louisiana Department of Highways for laboratory design of cement stabilized soil base and subbase courses is taken from standard AASHO test methods, patterned after Portland Cement Association criteria. These methods...

Do soil tests help forecast nitrogen response in first-year corn following alfalfa on fine-textured soils?

USDA-ARS?s Scientific Manuscript database

Improved methods of predicting grain yield response to fertilizer N for first-year corn (Zea mays L.) following alfalfa (Medicago sativa L.) on fine-textured soils are needed. Data from 21 site-years in the North Central Region were used to (i) determine how Illinois soil nitrogen test (ISNT) and pr...

An Inverse Method to Estimate the Root Water Uptake Source-Sink Term in Soil Water Transport Equation under the Effect of Superabsorbent Polymer

PubMed Central

Liao, Renkuan; Yang, Peiling; Wu, Wenyong; Ren, Shumei

2016-01-01

The widespread use of superabsorbent polymers (SAPs) in arid regions improves the efficiency of local land and water use. However, SAPs’ repeated absorption and release of water has periodic and unstable effects on both soil’s physical and chemical properties and on the growth of plant roots, which complicates modeling of water movement in SAP-treated soils. In this paper, we proposea model of soil water movement for SAP-treated soils. The residence time of SAP in the soil and the duration of the experiment were considered as the same parameter t. This simplifies previously proposed models in which the residence time of SAP in the soil and the experiment’s duration were considered as two independent parameters. Numerical testing was carried out on the inverse method of estimating the source/sink term of root water uptake in the model of soil water movement under the effect of SAP. The test results show that time interval, hydraulic parameters, test error, and instrument precision had a significant influence on the stability of the inverse method, while time step, layering of soil, and boundary conditions had relatively smaller effects. A comprehensive analysis of the method’s stability, calculation, and accuracy suggests that the proposed inverse method applies if the following conditions are satisfied: the time interval is between 5 d and 17 d; the time step is between 1000 and 10000; the test error is ≥ 0.9; the instrument precision is ≤ 0.03; and the rate of soil surface evaporation is ≤ 0.6 mm/d. PMID:27505000

Dynamic deformation of soft soil media: Experimental studies and mathematical modeling

NASA Astrophysics Data System (ADS)

Balandin, V. V.; Bragov, A. M.; Igumnov, L. A.; Konstantinov, A. Yu.; Kotov, V. L.; Lomunov, A. K.

2015-05-01

A complex experimental-theoretical approach to studying the problem of high-rate strain of soft soil media is presented. This approach combines the following contemporary methods of dynamical tests: the modified Hopkinson-Kolsky method applied tomedium specimens contained in holders and the method of plane wave shock experiments. The following dynamic characteristics of sand soils are obtained: shock adiabatic curves, bulk compressibility curves, and shear resistance curves. The obtained experimental data are used to study the high-rate strain process in the system of a split pressure bar, and the constitutive relations of Grigoryan's mathematical model of soft soil medium are verified by comparing the results of computational and natural test experiments of impact and penetration.

DNA recovery from soils of diverse composition.

PubMed

Zhou, J; Bruns, M A; Tiedje, J M

1996-02-01

A simple, rapid method for bacterial lysis and direct extraction of DNA from soils with minimal shearing was developed to address the risk of chimera formation from small template DNA during subsequent PCR. The method was based on lysis with a high-salt extraction buffer (1.5 M NaCl) and extended heating (2 to 3 h) of the soil suspension in the presence of sodium dodecyl sulfate (SDS), hexadecyltrimethylammonium bromide, and proteinase K. The extraction method required 6 h and was tested on eight soils differing in organic carbon, clay content, and pH, including ones from which DNA extraction is difficult. The DNA fragment size in crude extracts from all soils was > 23 kb. Preliminary trials indicated that DNA recovery from two soils seeded with gram-negative bacteria was 92 to 99%. When the method was tested on all eight unseeded soils, microscopic examination of indigenous bacteria in soil pellets before and after extraction showed variable cell lysis efficiency (26 to 92%). Crude DNA yields from the eight soils ranged from 2.5 to 26.9 micrograms of DNA g-1, and these were positively correlated with the organic carbon content in the soil (r = 0.73). DNA yields from gram-positive bacteria from pure cultures were two to six times higher when the high-salt-SDS-heat method was combined with mortar-and-pestle grinding and freeze-thawing, and most DNA recovered was of high molecular weight. Four methods for purifying crude DNA were also evaluated for percent recovery, fragment size, speed, enzyme restriction, PCR amplification, and DNA-DNA hybridization. In general, all methods produced DNA pure enough for PCR amplification. Since soil type and microbial community characteristics will influence DNA recovery, this study provides guidance for choosing appropriate extraction and purification methods on the basis of experimental goals.

Drawbar Pull

DTIC Science & Technology

2017-01-26

Includes procedures for hard surface, soil , and water tests. Discusses vehicle preparation, instrumentation method of computing results, data reduction...and amphibious vehicles. 15. SUBJECT TERMS Bollard pull Soft- soil mobility Drawbar pull Vehicle, amphibious Drawbar horsepower Vehicle...4.3 Drawbar Pull in Soft Soil ................................................. 8 4.4 Amphibious Vehicle Tests (Drawbar Pull in Water and Bollard Pull

Feasibility analysis of EDXRF method to detect heavy metal pollution in ecological environment

NASA Astrophysics Data System (ADS)

Hao, Zhixu; Qin, Xulei

2018-02-01

The change of heavy metal content in water environment, soil and plant can reflect the change of heavy metal pollution in ecological environment, and it is important to monitor the trend of heavy metal pollution in eco-environment by using water environment, soil and heavy metal content in plant. However, the content of heavy metals in nature is very low, the background elements of water environment, soil and plant samples are complex, and there are many interfering factors in the EDXRF system that will affect the spectral analysis results and reduce the detection accuracy. Through the contrastive analysis of several heavy metal elements detection methods, it is concluded that the EDXRF method is superior to other chemical methods in testing accuracy and method feasibility when the heavy metal pollution in soil is tested in ecological environment.

Yarding-method and slash-treatment effects on compaction, humus, and variation in plantation soils.

Treesearch

Don Minore; Howard G. Weatherly

1988-01-01

Soil penetration-resistance and soil-humus frequency were measured on 86 progeny-test plantations in southwestern Oregon to determine the effects of yarding method and slash treatment on soil compaction and humus, and a disturbance index was calculated for each plantation. Compaction and humus loss were more severe on tractor-yarded, machine-piled plantations than on...

A soil bioassay using the nematode Caenorhabditis elegans

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

Freeman, M.N.; Peredney, C.L.; Williams, P.L.

1999-07-01

Caenorhabditis elegans is a free-livings soil nematode that is commonly used as a biological model. Recently, much work has been done using the nematode as a toxicological model as well. Much of the work involving C. elegans has been performed in aquatic media, since it lives in the interstitial water of soil. However, testing in soil would be expected to more accurately reproduce the organism's normal environment and may take into consideration other factors not available in an aquatic test, i.e., toxicant availability effects due to sorption, various chemical interactions, etc. This study used a modification of a previous experimentalmore » protocol to determine 24h LC{sub 50} values for Cu in a Cecil series soil mixture, and examined the use of CuCl{sub 2} as a reference toxicant for soil toxicity testing with C. elegans. Three different methods of determining percent lethality were used, each dependent on how the number of worms missing after the recovery process was used in the lethality calculations. Only tests having {ge}80% worm recovery and {ge}90% control survival were used in determining the LC{sub 50}s, by Probit analysis. The replicate LC{sub 50} values generated a control chart for each method of calculating percent lethality. The coefficient of variation (CV) for each of the three methods was {le}14%. The control charts and the protocol outlined in this study are intended to be used to assess test organism health and monitor precision of future soil toxicity tests with C. elegans.« less

FUELS IN SOIL TEST KIT: FIELD USE OF DIESEL DOG SOIL TEST KITS

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

Unknown

2001-05-31

Western Research Institute (WRI) is commercializing Diesel Dog Portable Soil Test Kits for performing analysis of fuel-contaminated soils in the field. The technology consists of a method developed by WRI (U.S. Patents 5,561,065 and 5,976,883) and hardware developed by WRI that allows the method to be performed in the field (patent pending). The method is very simple and does not require the use of highly toxic reagents. The aromatic components in a soil extract are measured by absorption at 254 nm with a field-portable photometer. WRI added significant value to the technology by taking the method through the American Societymore » for Testing and Materials (ASTM) approval and validation processes. The method is designated ASTM Method D-5831-96, Standard Test Method for Screening Fuels in Soils. This ASTM designation allows the method to be used for federal compliance activities. In FY 99, twenty-five preproduction kits were successfully constructed in cooperation with CF Electronics, Inc., of Laramie, Wyoming. The kit components work well and the kits are fully operational. In the calendar year 2000, kits were provided to the following entities who agreed to participate as FY 99 and FY 00 JSR (Jointly Sponsored Research) cosponsors and use the kits as opportunities arose for field site work: Wyoming Department of Environmental Quality (DEQ) (3 units), F.E. Warren Air Force Base, Gradient Corporation, The Johnson Company (2 units), IT Corporation (2 units), TRC Environmental Corporation, Stone Environmental, ENSR, Action Environmental, Laco Associates, Barenco, Brown and Caldwell, Dames and Moore Lebron LLP, Phillips Petroleum, GeoSyntek, and the State of New Mexico. By early 2001, ten kits had been returned to WRI following the six-month evaluation period. On return, the components of all ten kits were fully functional. The kits were upgraded with circuit modifications, new polyethylene foam inserts, and updated instruction manuals.« less

Fate and transport of antimicrobials and antimicrobial resistance genes in soil and runoff following land application of swine manure slurry.

PubMed

Joy, Stacey R; Bartelt-Hunt, Shannon L; Snow, Daniel D; Gilley, John E; Woodbury, Bryan L; Parker, David B; Marx, David B; Li, Xu

2013-01-01

Due to the use of antimicrobials in livestock production, residual antimicrobials and antimicrobial resistance genes (ARGs) could enter the environment following the land application of animal wastes and could further contaminate surface and groundwater. The objective of this study was to determine the effect of various manure land application methods on the fate and transport of antimicrobials and ARGs in soil and runoff following land application of swine manure slurry. Swine manure slurries were obtained from facilities housing pigs that were fed chlortetracyline, tylosin or bacitracin and were land applied via broadcast, incorporation, and injection methods. Three rainfall simulation tests were then performed on amended and control plots. Results show that land application methods had no statistically significant effect on the aqueous concentrations of antimicrobials in runoff. However, among the three application methods tested broadcast resulted in the highest total mass loading of antimicrobials in runoff from the three rainfall simulation tests. The aqueous concentrations of chlortetracyline and tylosin in runoff decreased in consecutive rainfall events, although the trend was only statistically significant for tylosin. For ARGs, broadcast resulted in significantly higher erm genes in runoff than did incorporation and injection methods. In soil, the effects of land application methods on the fate of antimicrobials in top soil were compound specific. No clear trend was observed in the ARG levels in soil, likely because different host cells may respond differently to the soil environments created by various land application methods.

Assessment of soil compaction properties based on surface wave techniques

NASA Astrophysics Data System (ADS)

Jihan Syamimi Jafri, Nur; Rahim, Mohd Asri Ab; Zahid, Mohd Zulham Affandi Mohd; Faizah Bawadi, Nor; Munsif Ahmad, Muhammad; Faizal Mansor, Ahmad; Omar, Wan Mohd Sabki Wan

2018-03-01

Soil compaction plays an important role in every construction activities to reduce risks of any damage. Traditionally, methods of assessing compaction include field tests and invasive penetration tests for compacted areas have great limitations, which caused time-consuming in evaluating large areas. Thus, this study proposed the possibility of using non-invasive surface wave method like Multi-channel Analysis of Surface Wave (MASW) as a useful tool for assessing soil compaction. The aim of this study was to determine the shear wave velocity profiles and field density of compacted soils under varying compaction efforts by using MASW method. Pre and post compaction of MASW survey were conducted at Pauh Campus, UniMAP after applying rolling compaction with variation of passes (2, 6 and 10). Each seismic data was recorded by GEODE seismograph. Sand replacement test was conducted for each survey line to obtain the field density data. All seismic data were processed using SeisImager/SW software. The results show the shear wave velocity profiles increase with the number of passes from 0 to 6 passes, but decrease after 10 passes. This method could attract the interest of geotechnical community, as it can be an alternative tool to the standard test for assessing of soil compaction in the field operation.

Influence of subsoil and Soil Volume on the accumulation of nickel by Alyssum corsicum grown on a serpentine soil

USDA-ARS?s Scientific Manuscript database

Aims: Test the effect of soil volume and presence of subsoil on Ni hyperaccumulation. Methods: A. corsicum Duby was grown for 3 months on Chrome loam topsoil and subsoil from near Reistertown, MD, in a test of growth and Ni accumulation with varied soil masses (2.8 and 5.6 kg pot-1) to study the im...

Soil Sampling Techniques For Alabama Grain Fields

NASA Technical Reports Server (NTRS)

Thompson, A. N.; Shaw, J. N.; Mask, P. L.; Touchton, J. T.; Rickman, D.

2003-01-01

Characterizing the spatial variability of nutrients facilitates precision soil sampling. Questions exist regarding the best technique for directed soil sampling based on a priori knowledge of soil and crop patterns. The objective of this study was to evaluate zone delineation techniques for Alabama grain fields to determine which method best minimized the soil test variability. Site one (25.8 ha) and site three (20.0 ha) were located in the Tennessee Valley region, and site two (24.2 ha) was located in the Coastal Plain region of Alabama. Tennessee Valley soils ranged from well drained Rhodic and Typic Paleudults to somewhat poorly drained Aquic Paleudults and Fluventic Dystrudepts. Coastal Plain s o i l s ranged from coarse-loamy Rhodic Kandiudults to loamy Arenic Kandiudults. Soils were sampled by grid soil sampling methods (grid sizes of 0.40 ha and 1 ha) consisting of: 1) twenty composited cores collected randomly throughout each grid (grid-cell sampling) and, 2) six composited cores collected randomly from a -3x3 m area at the center of each grid (grid-point sampling). Zones were established from 1) an Order 1 Soil Survey, 2) corn (Zea mays L.) yield maps, and 3) airborne remote sensing images. All soil properties were moderately to strongly spatially dependent as per semivariogram analyses. Differences in grid-point and grid-cell soil test values suggested grid-point sampling does not accurately represent grid values. Zones created by soil survey, yield data, and remote sensing images displayed lower coefficient of variations (8CV) for soil test values than overall field values, suggesting these techniques group soil test variability. However, few differences were observed between the three zone delineation techniques. Results suggest directed sampling using zone delineation techniques outlined in this paper would result in more efficient soil sampling for these Alabama grain fields.

Characterization of Soil Samples of Enzyme Activity

ERIC Educational Resources Information Center

Freeland, P. W.

1977-01-01

Described are nine enzyme essays for distinguishing soil samples. Colorimetric methods are used to compare enzyme levels in soils from different sites. Each soil tested had its own spectrum of activity. Attention is drawn to applications of this technique in forensic science and in studies of soil fertility. (Author/AJ)

Field testing a mobile inelastic neutron scattering system to measure soil carbon

USDA-ARS?s Scientific Manuscript database

Cropping history in conjunction with soil management practices can have a major impact on the amount of organic carbon (C) stored in soil. Current methods of assessing soil C based on soil coring and subsequent processing procedures prior to laboratory analysis are labor intensive and time consuming...

Evaluation of soil processing conditions on mineralizable C and N across a textural gradient

USDA-ARS?s Scientific Manuscript database

Soil biological activity is an important component of a well-functioning soil. Methodologies for estimating this process in soil vary due to a variety of theoretical, functional, and expediency considerations. We tested the effects of soil processing (sieve size), water delivery method (from top a...

Static penetration resistance of soils

NASA Technical Reports Server (NTRS)

Durgunoglu, H. T.; Mitchell, J. K.

1973-01-01

Model test results were used to define the failure mechanism associated with the static penetration resistance of cohesionless and low-cohesion soils. Knowledge of this mechanism has permitted the development of a new analytical method for calculating the ultimate penetration resistance which explicitly accounts for penetrometer base apex angle and roughness, soil friction angle, and the ratio of penetration depth to base width. Curves relating the bearing capacity factors to the soil friction angle are presented for failure in general shear. Strength parameters and penetrometer interaction properties of a fine sand were determined and used as the basis for prediction of the penetration resistance encountered by wedge, cone, and flat-ended penetrometers of different surface roughness using the proposed analytical method. Because of the close agreement between predicted values and values measured in laboratory tests, it appears possible to deduce in-situ soil strength parameters and their variation with depth from the results of static penetration tests.

Comparative evaluation of subgrade resilient modulus from non-destructive, in-situ, and laboratory methods.

DOT National Transportation Integrated Search

2007-08-01

Field and laboratory testing programs were conducted to develop models that predict the resilient modulus of subgrade soils from : the test results of DCP, CIMCPT, FWD, Dynaflect, and soil properties. The field testing program included DCP, CIMCPT, F...

Testing the regionalization of a SVAT model for a region with high observation density

NASA Astrophysics Data System (ADS)

Eiermann, Sven; Thies, Boris; Bendix, Jörg

2014-05-01

The variable soil moisture is an important quantity in weather and climate investigations, because it has an essential influence on the energy exchange between the land surface and the atmosphere. However the recording of soil moisture in high spatio-temporal resolution is problematic. The planned Tandem-L mission of the German Aerospace Center (DLR) with an innovative L-band radar on board provides the opportunity to get daily soil moisture data at a spatial resolution of 50 meters. Within the Helmholtz Alliance Remote Sensing and Earth System Dynamics this data is planned to be used to regionalize a Soil Vegetation Atmosphere Transfer Model, in order to analyze the energy flux and the gas exchange and to improve the prediction of the water exchange between soil, vegetation and atmosphere. As investigation areas selected regions of the TERENO (TERrestrial ENviromental Observatoria) test sites and, later on, a region in South Ecuador will be used, for which data for the model initialization and validation are available. The reason for testing the method for the TERENO test sites first is the good data basis as a result of the already established high observation density there. The poster will present the methods being used for the model adaptation for the TERENO test sites and discuss the improvements achieved by these methods.

An analysis of the static load test on single square pile of 40x40 cm2, using finite element method in Rusunawa project, Jatinegara, Jakarta

NASA Astrophysics Data System (ADS)

Harasid, Harun; Roesyanto; Iskandar, Rudi; Silalahi, Sofyan A.

2018-03-01

Piling Foundation is one of the foundations which is used to penetrate its load through soil layer. The power carried by the piling is obtained from the end bearing capacity, that is, the compressive end piling and friction bearing capacity obtained from friction bearing and adhesive capacity between the piling and the soil around it. The investigation on the Standard Penetration Test is aimed to get the description of soil layer, based on the type and color of soil through visual observation, and soil characteristics. SPT data can be used to calculate bearing capacity. Besides investigating the SPT, this study is also been equipped by taking the samples in laboratory and loading test on the piling and Ducth Cone Penetrometer (DCP) data to confirm its bearing capacity. This study analyzed bearing capacity and settlement in the square pile of 40X40 cm in diameter in a single pile or grouped, using an empirical method, AllPile program, Plaxis program, and comparing the result with interpreting its loading test in the foundation of Rusunawa project, Jatinegara, Jakarta. The analysis was been done by using the data on soil investigation and laboratory by comparing them with Mohr-Coulomb soil model. Ultimate bearing capacity from the SPT data in the piling of 15.4 meters was 189.81 tons and the parameter of soil shear strength was 198.67 tons. The sander point, based on Aoki and De Alencar bearing capacity was 276.241 tons and based on Mayerhoff it was 305.49 tons. Based on the loading test of bearing capacity, unlimited bearing capacity for the three methods was Davisson (260 tons), Mazurkiewich (270 tons), and Chin (250 tons). The efficiency of grouped piles according to Converse-Library Equation method = 0.73, according to Los Angeles Group Action Equation method = 0.59, and according to Sheila-Keeny method = 0.94. Bearing capacity based on piling strength was 221.76 tons, bearing capacity based on calendaring data was 201.71 tons, and lateral bearing capacity of a single piling foundation was 129.6 kN (12.96 tons). When the maximum load (280 tons) was been given, more decrease occurred in the Maintained load test of 21.00 mm and Quick Load Test method of 20.67 mm, compared with the result of Load Test in the field of 18.74 mm. Based on ASTM D1143/81, the permitted value was 25.40 mm. Therefore, based on that decreasing, it could be concluded that foundation piles were safe in the construction. The pore water pressure is highly influenced by time so that in Maintained Load Test and Quick Load Test, there was the disparity in the level of pore water pressure. Based on the result of the calculation, Quick Load Test showed that in pore water pressure was dissipated in its acceleration.

Novel diffusive gradients in thin films technique to assess labile sulfate in soil.

PubMed

Hanousek, Ondrej; Mason, Sean; Santner, Jakob; Chowdhury, Md Mobaroqul Ahsan; Berger, Torsten W; Prohaska, Thomas

2016-09-01

A novel diffusive gradients in thin films (DGT) technique for sampling labile soil sulfate was developed, based on a strong basic anion exchange resin (Amberlite IRA-400) for sulfate immobilization on the binding gel. For reducing the sulfate background on the resin gels, photopolymerization was applied instead of ammonium persulfate-induced polymerization. Agarose cross-linked polyacrylamide (APA) hydrogels were used as diffusive layer. The sulfate diffusion coefficient in APA gel was determined as 9.83 × 10(-6) ± 0.35 × 10(-6) cm(2) s(-1) at 25 °C. The accumulated sulfate was eluted in 1 mol L(-1) HNO3 with a recovery of 90.9 ± 1.6 %. The developed method was tested against two standard extraction methods for soil sulfate measurement. The obtained low correlation coefficients indicate that DGT and conventional soil test methods assess differential soil sulfate pools, rendering DGT a potentially important tool for measuring labile soil sulfate.

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

PubMed

Majid, Abdul Hafiz Ab; Ahmad, Abu Hassan

2013-12-01

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

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

PubMed Central

Majid, Abdul Hafiz Ab; Ahmad, Abu Hassan

2013-01-01

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

SITE EVALUATION OF SOIL AMENDMENT TECHNOLOGIES AT THE CROOKSVILLE/ROSEVILLE POTTERY AREA OF CONCERN - STAR ORGANICS SOIL RESCUE CAPSULE

EPA Science Inventory

This report briefly summarizes Star Organics treatment technology demonstration of a soil amendment process for lead contaminated soil at Roseville, OH. The evaluation included leaching, bioavailability, geotechnical, and geochemical testing methods.

LEAK AND GAS PERMEABILITY TESTING DURING SOIL-GAS SAMPLING AT HAL'S CHEVRON LUST SITE IN GREEN RIVER, UTAH

EPA Science Inventory

The results of gas permeability and leak testing during active soil-gas sampling at Hal’s Chevron LUST Site in Green River, Utah are presented. This study was conducted to support development of a passive soil-gas sampling method. Gas mixtures containing helium and methane were...

Measuring the electrical properties of soil using a calibrated ground-coupled GPR system

USGS Publications Warehouse

Oden, C.P.; Olhoeft, G.R.; Wright, D.L.; Powers, M.H.

2008-01-01

Traditional methods for estimating vadose zone soil properties using ground penetrating radar (GPR) include measuring travel time, fitting diffraction hyperbolae, and other methods exploiting geometry. Additional processing techniques for estimating soil properties are possible with properly calibrated GPR systems. Such calibration using ground-coupled antennas must account for the effects of the shallow soil on the antenna's response, because changing soil properties result in a changing antenna response. A prototype GPR system using ground-coupled antennas was calibrated using laboratory measurements and numerical simulations of the GPR components. Two methods for estimating subsurface properties that utilize the calibrated response were developed. First, a new nonlinear inversion algorithm to estimate shallow soil properties under ground-coupled antennas was evaluated. Tests with synthetic data showed that the inversion algorithm is well behaved across the allowed range of soil properties. A preliminary field test gave encouraging results, with estimated soil property uncertainties (????) of ??1.9 and ??4.4 mS/m for the relative dielectric permittivity and the electrical conductivity, respectively. Next, a deconvolution method for estimating the properties of subsurface reflectors with known shapes (e.g., pipes or planar interfaces) was developed. This method uses scattering matrices to account for the response of subsurface reflectors. The deconvolution method was evaluated for use with noisy data using synthetic data. Results indicate that the deconvolution method requires reflected waves with a signal/noise ratio of about 10:1 or greater. When applied to field data with a signal/noise ratio of 2:1, the method was able to estimate the reflection coefficient and relative permittivity, but the large uncertainty in this estimate precluded inversion for conductivity. ?? Soil Science Society of America.

Improving the spatial representation of soil properties and hydrology using topographically derived watershed model initialization processes

NASA Astrophysics Data System (ADS)

Easton, Z. M.; Fuka, D.; Collick, A.; Kleinman, P. J. A.; Auerbach, D.; Sommerlot, A.; Wagena, M. B.

2015-12-01

Topography exerts critical controls on many hydrologic, geomorphologic, and environmental biophysical processes. Unfortunately many watershed modeling systems use topography only to define basin boundaries and stream channels and do not explicitly account for the topographic controls on processes such as soil genesis, soil moisture distributions and hydrological response. We develop and demonstrate a method that uses topography to spatially adjust soil morphological and soil hydrological attributes [soil texture, depth to the C-horizon, saturated conductivity, bulk density, porosity, and the field capacities at 33kpa (~ field capacity) and 1500kpa (~ wilting point) tensions]. In order to test the performance of the method the topographical adjusted soils and standard SSURGO soil (available at 1:20,000 scale) were overlaid on soil pedon pit data in the Grasslands Soil and Water Research Lab in Resiel, TX. The topographically adjusted soils exhibited significant correlations with measurements from the soil pits, while the SSURGO soil data showed almost no correlation to measured data. We also applied the method to the Grasslands Soil and Water Research watershed using the Soil and Water Assessment Tool (SWAT) model to 15 separate fields as a proxy to propagate changes in soil properties into field scale hydrological responses. Results of this test showed that the topographically adjusted soils resulted better model predictions of field runoff in 50% of the field, with the SSURGO soils preforming better in the remainder of the fields. However, the topographically adjusted soils generally predicted baseflow response more accurately, reflecting the influence of these soil properties on non-storm responses. These results indicate that adjusting soil properties based on topography can result in more accurate soil characterization and, in some cases improve model performance.

Proposed modification to avoidance test with Eisenia fetida to assess metal toxicity in agricultural soils affected by mining activities.

PubMed

Delgadillo, Víctor; Verdejo, José; Mondaca, Pedro; Verdugo, Gabriela; Gaete, Hernán; Hodson, Mark E; Neaman, Alexander

2017-06-01

Use of avoidance tests is a quick and cost-effective method of assessing contaminants in soils. One option for assessing earthworm avoidance behavior is a two-section test, which consists of earthworms being given the choice to move between a test soil and a control substrate. For ecological relevance, tested soils should be field-contaminated soils. For practical reasons, artificial soils are commonly used as the control substrate. Interpretation of the test results compromised when the test soil and the artificial substrate differ in their physico-chemical properties other than just contaminants. In this study we identified the physico-chemical properties that influence avoidance response and evaluated the usefulness of adjusting these in the control substrate in order to isolate metal-driven avoidance of field soils by earthworms. A standardized two-section avoidance test with Eisenia fetida was performed on 52 uncontaminated and contaminated (Cu >155mgkg -1 , As >19mgkg -1 ) agricultural soils from the Aconcagua River basin and the Puchuncaví Valley in Chile. Regression analysis indicated that the avoidance response was determined by soil organic matter (OM), electrical conductivity (EC) and total soil Cu. Organic matter content of the artificial substrate was altered by peat additions and EC by NaCl so that these properties matched those of the field soils. The resultant EC 80 for avoidance (indicative of soils of "limited habitat") was 433mg Cu kg -1 (339 - 528mgkg -1 95% confidence intervals). The earthworm avoidance test can be used to assess metal toxicity in field-contaminated soils by adjusting physico-chemical properties (OM and EC) of the artificial control substrate in order to mimic those of the field-collected soil. Copyright © 2017 Elsevier Inc. All rights reserved.

Measuring temperature dependence of soil respiration: importance of incubation time, soil type, moisture content and model fits

NASA Astrophysics Data System (ADS)

Schipper, L. A.; Robinson, J.; O'Neill, T.; Ryburn, J.; Arcus, V. L.

2015-12-01

Developing robust models of the temperature response and sensitivity of soil respiration is critical for determining changes carbon cycling in response to climate change and at daily to annual time scales. Currently, approaches for measuring temperature dependence of soil respiration generally use long incubation times (days to weeks and months) at a limited number of incubation temperatures. Long incubation times likely allow thermal adaptation by the microbial population so that results are poorly representative of in situ soil responses. Additionally, too few incubation temperatures allows for the fit and justification of many different predictive equations, which can lead to inaccuracies when used for carbon budgeting purposes. We have developed a method to rapidly determine the response of soil respiration rate to wide range of temperatures. An aluminium block with 44 sample slots is heated at one end and cooled at the other to give a temperature gradient from 0 to 55°C at about one degree increments. Soil respiration is measured within 5 hours to minimise the possibility of thermal adaptation. We have used this method to demonstrate the similarity of temperature sensitivity of respiration for different soils from the same location across seasons. We are currently testing whether long-term (weeks to months) incubation alter temperature response and sensitivity that occurs in situ responses. This method is also well suited for determining the most appropriate models of temperature dependence and sensitivity of soil respiration (including macromolecular rate theory MMRT). With additional testing, this method is expected to be a more reliable method of measuring soil respiration rate for soil quality and modelling of soil carbon processes.

Aquifer sensitivity to pesticide leaching: Testing a soils and hydrogeologic index method

USGS Publications Warehouse

Mehnert, E.; Keefer, D.A.; Dey, W.S.; Wehrmann, H.A.; Wilson, S.D.; Ray, C.

2005-01-01

For years, researchers have sought index and other methods to predict aquifer sensitivity and vulnerability to nonpoint pesticide contamination. In 1995, an index method and map were developed to define aquifer sensitivity to pesticide leaching based on a combination of soil and hydrogeologic factors. The soil factor incorporated three soil properties: hydraulic conductivity, amount of organic matter within individual soil layers, and drainage class. These properties were obtained from a digital soil association map. The hydrogeologic factor was depth to uppermost aquifer material. To test this index method, a shallow ground water monitoring well network was designed, installed, and sampled in Illinois. The monitoring wells had a median depth of 7.6 m and were located adjacent to corn and soybean fields where the only known sources of pesticides were those used in normal agricultural production. From September 1998 through February 2001, 159 monitoring wells were sampled for 14 pesticides but no pesticide metabolites. Samples were collected and analyzed to assess the distribution of pesticide occurrence across three units of aquifer sensitivity. Pesticides were detected in 18% of all samples and nearly uniformly from samples from the three units of aquifer sensitivity. The new index method did not predict pesticide occurrence because occurrence was not dependent on the combined soil and hydrogeologic factors. However, pesticide occurrence was dependent on the tested hydrogeologic factor and was three times higher in areas where the depth to the uppermost aquifer was <6 m than in areas where the depth to the uppermost aquifer was 6 to <15 m. Copyright ?? 2005 National Ground Water Association.

Determination of total carbonates in soil archaeometry using a new pressure method with temperature compensation

NASA Astrophysics Data System (ADS)

Barouchas, Pantelis; Koulos, Vasilios; Melfos, Vasilios

2017-04-01

For the determination of total carbonates in soil archaeometry a new technique was applied using a multi-sensor philosophy, which combines simultaneous measurement of pressure and temperature. This technology is innovative and complies with EN ISO 10693:2013, ASTM D4373-02(2007) and Soil Science Society of America standard test methods for calcium carbonate content in soils and sediments. The total carbonates analysis is based on a pressure method that utilizes the FOGII Digital Soil CalcimeterTM, which is a portable apparatus. The total carbonate content determined by treating a 1.000 g (+/- 0.001 g) dried sample specimens with 6N hydrochloric acid (HCL) reagent grade, in an enclosed reaction vessel. Carbon dioxide gas evolved during the reaction between the acid and carbonate fraction of the specimen, was measured by the resulting pressure generated, taking in account the temperature conditions during the reaction. Prior to analysis the procedure was validated with Sand/Soil mixtures from BIPEA proficiency testing program with soils of different origins. For applying this new method in archaeometry a total number of ten samples were used from various rocks which are related with cultural constructions and implements in Greece. They represent a large range of periods since the Neolithic times, and were selected because there was an uncertainty about their accurate mineralogical composition especially regarding the presence of carbonate minerals. The results were compared to the results from ELTRA CS580 inorganic carbon analyzer using an infrared cell. The determination of total carbonates for 10 samples from different ancient sites indicated a very good correlation (R2 >0.97) between the pressure method with temperature compensation and the infrared method. The proposed method is quickly and accurate in archaeometry and can replace easily other techniques for total carbonates testing. The FOGII Digital Soil CalcimeterTM is portable and easily can be carried for field work in archaeology.

SUPERFUND TREATABILITY CLEARINGHOUSE: BDAT FOR SOLIDIFICATION/STABILIZATION TECHNOLOGY FOR SUPERFUND SOILS (DRAFT FINAL REPORT)

EPA Science Inventory

This report evaluates the performance of solidification as a method for treating solids from Superfund sites. Tests were conducted on four different artificially contaminated soils which are representative of soils found at the sites. Contaminated soils were solidified us...

The surface area of soil organic matter

USGS Publications Warehouse

Chiou, C.T.; Lee, J.-F.; Boyd, S.A.

1990-01-01

The previously reported surface area for soil organic matter (SOM) of 560-800 m2/g as determined by the ethylene glycol (EG) retention method was reexamined by the standard BET method based on nitrogen adsorption at liquid nitrogen temperature. Test samples consisted of two high organic content soils, a freeze-dried soil humic acid, and an oven-dried soil humic acid. The measured BET areas for these samples were less than 1 m2/g, except for the freeze-dried humic acid. The results suggest that surface adsorption of nonionic organic compounds by SOM is practically insignificant in comparison to uptake by partition. The discrepancy between the surface areas of SOM obtained by BET and EG methods was explained in terms of the 'free surface area' and the 'apparent surface area' associated with these measurements.The previously reported surface area for soil organic matter (SOM) of 560-800 m2/g as determined by the ethylene glycol (EG) retention method was reexamined by the standard BET method based on nitrogen adsorption at liquid nitrogen temperature. Test samples consisted of two high organic content soils, a freeze-dried soil humic acid, and an oven-dried soil humic acid. The measured BET areas for these samples were less than 1 m2/g, except for the freeze-dried humic acid. The results suggest that surface adsorption of nonionic organic compounds by SOM is practically insignificant in comparison to uptake by partition. The discrepancy between the surface areas of SOM obtained by BET and EG methods was explained in terms of the 'free surface area' and the 'apparent surface area' associated with these measurements.

Uptakes of Cs and Sr on San Joaquin soil measured following ASTM method C1733.

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

Ebert, W.L.; Petri, E.T.

2012-04-04

Series of tests were conducted following ASTM Standard Procedure C1733 to evaluate the repeatability of the test and the effects of several test parameters, including the solution-to-soil mass ratio, test duration, pH, and the concentrations of contaminants in the solution. This standard procedure is recommended for measuring the distribution coefficient (K{sub d}) of a contaminant in a specific soil/groundwater system. One objective of the current tests was to identify experimental conditions that can be used in future interlaboratory studies to determine the reproducibility of the test method. This includes the recommendation of a standard soil, the range of contaminant concentrationsmore » and solution matrix, and various test parameters. Quantifying the uncertainty in the distribution coefficient that can be attributed to the test procedure itself allows the differences in measured values to be associated with differences in the natural systems being studied. Tests were conducted to measure the uptake of Cs and Sr dissolved as CsCl and Sr(NO{sub 3}){sub 2} in a dilute NaHCO{sub 3}/SiO{sub 2} solution (representing contaminants in a silicate groundwater) by a NIST standard reference material of San Joaquin soil (SRM 2709a). Tests were run to measure the repeatability of the method and the sensitivity of the test response to the reaction time, the mass of soil used (at a constant soil-to-solution ratio), the solution pH, and the contaminant concentration. All tests were conducted in screw-top Teflon vessels at 30 C in an oven. All solutions were passed through a 0.45-{mu}m pore size cellulose acetate membrane filter and stabilized with nitric acid prior to analysis with inductively-coupled plasma mass spectrometry (ICP-MS). Scoping tests with soil in demineralized water resulted in a solution pH of about 8.0 and the release of small amounts of Sr from the soil. Solutions were made with targeted concentrations of 1 x 10{sup -6} m, 1 x 10{sup -5} m, 2.5 x 10{sup -5} m, 5 x 10{sup -5} m, 1 x 10{sup -4} m, and 5 x 10{sup -4} m to measure the effects of the Cs and Sr concentrations on their uptake by the soil. The pH values of all solutions were adjusted to about pH 8.5 so that the effects of pH and concentration could be measured separately. The 1 x 10{sup -4} m solutions were used to measure the repeatability of the test and the effects of duration, scale, and imposed pH on the test response.« less

A New Non-Destructive TDR System Combined with a Piezoelectric Stack for Measuring Properties of Geomaterials

PubMed Central

Choi, Chanyong; Song, Minwoo; Kim, Daehyeon; Yu, Xiong

2016-01-01

Dry density and water content are two important factors affecting the degree of soil compaction. Conventional methods such as the sand cone test and the plate load test are used to measure such properties for evaluating the degree of compaction and the stiffness of soil in the field. However, these tests are generally very time-consuming and are inherent with some errors depending on the operator (in particular for the sand cone test). Elastic modulus is an indicator to describe the stress-strain behavior of soil and in some cases is used as a design input parameter. Although a rod type TDR (Time Domain Reflectometry) system has been recently proposed to overcome some shortcomings of the conventional methods (particularly the sand cone test), it requires driving the probes into the ground, thus implying that it is still a time-consuming and destructive testing method. This study aims to develop a new non-destructive TDR system that can rapidly measure the dry density, water content, and elastic modulus of soil on the surface of compacted soil, without disturbing the ground. In this study, the Piezoelectric Stack, which is an instrument for measuring the elastic modulus of soil, has been added to the TDR system with a flat type probe, leading to a non-destructive TDR system that is capable of measuring the dry density, water content, and elastic modulus of soil. The new TDR system developed is light enough for an engineer to carry. Results of the standard compaction and TDR tests on sand showed that the dry densities and the moisture contents measured with the new TDR system were in good agreement with those measured with the standard compaction test, respectively. Consequently, it appears that the new TDR system developed will be very useful to advance the current practice of compaction quality control. PMID:28773563

A New Non-Destructive TDR System Combined with a Piezoelectric Stack for Measuring Properties of Geomaterials.

PubMed

Choi, Chanyong; Song, Minwoo; Kim, Daehyeon; Yu, Xiong

2016-06-02

Dry density and water content are two important factors affecting the degree of soil compaction. Conventional methods such as the sand cone test and the plate load test are used to measure such properties for evaluating the degree of compaction and the stiffness of soil in the field. However, these tests are generally very time-consuming and are inherent with some errors depending on the operator (in particular for the sand cone test). Elastic modulus is an indicator to describe the stress-strain behavior of soil and in some cases is used as a design input parameter. Although a rod type TDR (Time Domain Reflectometry) system has been recently proposed to overcome some shortcomings of the conventional methods (particularly the sand cone test), it requires driving the probes into the ground, thus implying that it is still a time-consuming and destructive testing method. This study aims to develop a new non-destructive TDR system that can rapidly measure the dry density, water content, and elastic modulus of soil on the surface of compacted soil, without disturbing the ground. In this study, the Piezoelectric Stack, which is an instrument for measuring the elastic modulus of soil, has been added to the TDR system with a flat type probe, leading to a non-destructive TDR system that is capable of measuring the dry density, water content, and elastic modulus of soil. The new TDR system developed is light enough for an engineer to carry. Results of the standard compaction and TDR tests on sand showed that the dry densities and the moisture contents measured with the new TDR system were in good agreement with those measured with the standard compaction test, respectively. Consequently, it appears that the new TDR system developed will be very useful to advance the current practice of compaction quality control.

Rapid Method of Determining Factors Limiting Bacterial Growth in Soil

PubMed Central

Aldén, L.; Demoling, F.; Bååth, E.

2001-01-01

A technique to determine which nutrients limit bacterial growth in soil was developed. The method was based on measuring the thymidine incorporation rate of bacteria after the addition of C, N, and P in different combinations to soil samples. First, the thymidine incorporation method was tested in two different soils: an agricultural soil and a forest humus soil. Carbon (as glucose) was found to be the limiting substance for bacterial growth in both of these soils. The effect of adding different amounts of nutrients was studied, and tests were performed to determine whether the additions affected the soil pH and subsequent bacterial activity. The incubation time required to detect bacterial growth after adding substrate to the soil was also evaluated. Second, the method was used in experiments in which three different size fractions of straw (1 to 2, 0.25 to 1, and <0.25 mm) were mixed into the agricultural soil in order to induce N limitation for bacterial growth. When the straw fraction was small enough (<0.25 mm), N became the limiting nutrient for bacterial growth after about 3 weeks. After the addition of the larger straw fractions (1 to 2 and 0.25 to 1 mm), the soil bacteria were C limited throughout the incubation period (10 weeks), although an increase in the thymidine incorporation rate after the addition of C and N together compared with adding them separately was seen in the sample containing the size fraction from 0.25 to 1 mm. Third, soils from high-pH, limestone-rich areas were examined. P limitation was observed in one of these soils, while tendencies toward P limitation were seen in some of the other soils. PMID:11282640

Assessment of current AASHTO LRFD methods for static pile capacity analysis in Rhode Island soils.

DOT National Transportation Integrated Search

2013-07-01

This report presents an assessment of current AASHTO LRFD methods for static pile capacity analysis in Rhode : Island soils. Current static capacity methods and associated resistance factors are based on pile load test data in sands : and clays. Some...

Normalized Rotational Multiple Yield Surface Framework (NRMYSF) stress-strain curve prediction method based on small strain triaxial test data on undisturbed Auckland residual clay soils

NASA Astrophysics Data System (ADS)

Noor, M. J. Md; Ibrahim, A.; Rahman, A. S. A.

2018-04-01

Small strain triaxial test measurement is considered to be significantly accurate compared to the external strain measurement using conventional method due to systematic errors normally associated with the test. Three submersible miniature linear variable differential transducer (LVDT) mounted on yokes which clamped directly onto the soil sample at equally 120° from the others. The device setup using 0.4 N resolution load cell and 16 bit AD converter was capable of consistently resolving displacement of less than 1µm and measuring axial strains ranging from less than 0.001% to 2.5%. Further analysis of small strain local measurement data was performed using new Normalized Multiple Yield Surface Framework (NRMYSF) method and compared with existing Rotational Multiple Yield Surface Framework (RMYSF) prediction method. The prediction of shear strength based on combined intrinsic curvilinear shear strength envelope using small strain triaxial test data confirmed the significant improvement and reliability of the measurement and analysis methods. Moreover, the NRMYSF method shows an excellent data prediction and significant improvement toward more reliable prediction of soil strength that can reduce the cost and time of experimental laboratory test.

An empirical method to estimate shear wave velocity of soils in the New Madrid seismic zone

USGS Publications Warehouse

Wei, B.-Z.; Pezeshk, S.; Chang, T.-S.; Hall, K.H.; Liu, Huaibao P.

1996-01-01

In this study, a set of charts are developed to estimate shear wave velocity of soils in the New Madrid seismic zone (NMSZ), using the standard penetration test (SPT) N values and soil depths. Laboratory dynamic test results of soil samples collected from the NMSZ showed that the shear wave velocity of soils is related to the void ratio and the effective confining pressure applied to the soils. The void ratio of soils can be estimated from the SPT N values and the effective confining pressure depends on the depth of soils. Therefore, the shear wave velocity of soils can be estimated from the SPT N value and the soil depth. To make the methodology practical, two corrections should be made. One is that field SPT N values of soils must be adjusted to an unified SPT N??? value to account the effects of overburden pressure and equipment. The second is that the effect of water table to effective overburden pressure of soils must be considered. To verify the methodology, shear wave velocities of five sites in the NMSZ are estimated and compared with those obtained from field measurements. The comparison shows that our approach and the field tests are consistent with an error of less than of 15%. Thus, the method developed in this study is useful for dynamic study and practical designs in the NMSZ region. Copyright ?? 1996 Elsevier Science Limited.

Development of internal forest soil reference samples and testing of digestion methods

Treesearch

J.E. Hislop; J.W. Hornbeck; S.W. Bailey; R.A. Hallett

1998-01-01

Our research requires determinations of total elemental concentrations of forest soils. The lack of certified forest soil reference materials led us to develop internal reference samples. Samples were collected from three soil horizons (Oa, B, and C) at three locations having forested, acidic soils similar to those we commonly analyze. A shatterbox was used to...

Effect of biochar activation by different methods on toxicity of soil contaminated by industrial activity.

PubMed

Kołtowski, Michał; Charmas, Barbara; Skubiszewska-Zięba, Jadwiga; Oleszczuk, Patryk

2017-02-01

The objective of the study was to determine the effect of various methods of biochar activation on the ecotoxicity of soils with various properties and with various content and origin of contaminants. The biochar produced from willow (at 700°C) was activated by 1) microwaves (in a microwave reactor under an atmosphere of water vapour), 2) carbon dioxide (in the quartz fluidized bed reactor) and 3) superheated steam (in the quartz fluidized bed reactor). Three different soils were collected from industrial areas. The soils were mixed with biochar and activated biochars at the dose of 5% and ecotoxicological parameters of mixture was evaluated using two solid phase test - Phytotoxkit F (Lepidium sativum) and Collembolan test (Folsomia candida) and one liquid phase test - Microtox® (Vibrio fischeri). Biochar activation had both positive and negative impacts, depending on the activation method, kind of bioassay and kind of soil. Generally, biochar activated by microwaves increased the effectiveness of ecotoxicity reduction relative to non-activated biochars. Whereas, biochar activated with CO 2 most often cause a negative effect manifested by deterioration or as a lack of improvement in relation to non-activated biochar or to non-amended soil. It was also demonstrated that the increase of biochar specific surface area caused a significant reduction of toxicity of water leachates from the studied soils. Effectiveness of the reduction of leachate toxicity was weakened in the presence of dissolved organic carbon in the soil. Copyright © 2016 Elsevier Inc. All rights reserved.

Radar Cuts Subsoil Survey Costs

NASA Technical Reports Server (NTRS)

Johnson, R.; Glaccum, R.

1984-01-01

Soil features located with minimum time and labor. Ground-penetrating radar (GPR) system supplements manual and mechanical methods in performing subsurface soil survey. Mobile system obtains graphic profile of soil discontinuities and interfaces as function of depth. One or two test borings necessary to substantiate soil profile. GPR proves useful as reconnaissance tool.

Comparison of basic laboratory test results with more sophisticated laboratory and in-situ tests methods on soils in southeastern Wisconsin : final report, March 21, 2009.

DOT National Transportation Integrated Search

2009-03-21

This study investigates all of the generated soils data in an attempt to use the more 'routine' laboratory tests to determine geotechnical design parameters (such as phiangle, cohesion, wet unit weight, unconfined compression, consolidation character...

Accelerated detection of brown-rot decay : comparison of soil block test, chemical analysis, mechanical properties, and immunodetection

Treesearch

C. A. Clausen; S. N. Kartal

2003-01-01

Early detection of wood decay is critical because decay fungi can cause rapid structural failure. The objective of this study was to compare the sensitivity of different methods purported to detect brown-rot decay in the early stages of development. The immunodiagnostic wood decay (IWD)test, soil block test/cake pan test, mechanical property tests, and chemical...

Use of the laboratory tests of soil modulus in modelling pile behaviour

NASA Astrophysics Data System (ADS)

Dyka, Ireneusz

2012-10-01

This article deals with the question of theoretical description of behaviour of a single pile rested in a layered soil medium. Particular attention is paid to soil modulus which is used in calculation method for pile load-settlement curve. A brief analysis of the results obtained by laboratory tests to assess soil modulus and its nonlinear variability has been presented. The results of tests have been used in triaxial apparatus and resonant column/torsional shear device. There have also been presented the results of load-settlement calculation for a single pile under axial load with implementation of different models of soil modulus degradation. On this basis, possibilities of using particular kinds of laboratory tests in calculation procedure of foundation settlement have been presented as well as further developments of them.

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

NASA Astrophysics Data System (ADS)

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.

Resilient moduli of typical Missouri soils and unbound granular base materials

DOT National Transportation Integrated Search

2008-03-01

The objective of this project is to accurately determine the resilient moduli for common Missouri subgrade soils and unbound granular base materials in accordance with the AASHTO T 307 test method. The test results included moduli data from 27 common...

Comparative Efficiency of the Fenwick Can and Schuiling Centrifuge in Extracting Nematode Cysts from Different Soil Types

PubMed Central

Bellvert, Joaquim; Crombie, Kieran; Horgan, Finbarr G.

2008-01-01

The Fenwick can and Schuiling centrifuge are widely used to extract nematode cysts from soil samples. The comparative efficiencies of these two methods during cyst extraction have not been determined for different soil types under different cyst densities. Such information is vital for statutory laboratories that must choose a method for routine, high-throughput soil monitoring. In this study, samples of different soil types seeded with varying densities of potato cyst nematode (Globodera rostochiensis) cysts were processed using both methods. In one experiment, with 200 ml samples, recovery was similar between methods. In a second experiment with 500 ml samples, cyst recovery was higher using the Schuiling centrifuge. For each method and soil type, cyst extraction efficiency was similar across all densities tested. Extraction was efficient from pure sand (Fenwick 72%, Schuiling 84%) and naturally sandy soils (Fenwick 62%, Schuiling 73%), but was significantly less efficient from clay-soil (Fenwick 42%, Schuiling 44%) and peat-soil with high organic matter content (Fenwick 35%, Schuiling 33%). Residual moisture (<10% w/w) in samples prior to analyses reduced extraction efficiency, particularly for sand and sandy soils. For each soil type and method, there were significant linear relationships between the number of cysts extracted and the numbers of cysts in the samples. We discuss the advantages and disadvantages of each extraction method for cyst extraction in statutory soil laboratories. PMID:19259516

Geotechnical soil characterization of intact Quaternary deposits forming the March 22, 2014 SR-530 (Oso) landslide, Snohomish County, Washington

USGS Publications Warehouse

Riemer, Michael F.; Collins, Brian D.; Badger, Thomas C.; Toth, Csilla; Yu, Yat Chun

2015-01-01

This report provides a description of the methods used to obtain and test the intact soil stratigraphy behind the headscarp of the March 22 landslide. Detailed geotechnical index testing results are presented for 24 soil samples representing the stratigraphy at 19 different depths along a 650 ft (198 m) soil profile. The results include (1) the soil's in situ water content and unit weight (where applicable); (2) specific gravity of soil solids; and (3) each sample's grain-size distribution, critical limits for fine-grain water content states (that is, the Atterberg limits), and official Unified Soil Classification System (USCS) designation. In addition, preliminary stratigraphy and geotechnical relations within and between soil units are presented.

Enhanced Cover Assessment Project:Soil Manipulation and Revegetation Tests

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

Waugh, W. Joseph; Albright, Dr. Bill; Benson, Dr. Craig

2014-02-01

The U.S. Department of Energy Office of Legacy Management is evaluating methods to enhance natural changes that are essentially converting conventional disposal cell covers for uranium mill tailings into water balance covers. Conventional covers rely on a layer of compacted clayey soil to limit exhalation of radon gas and percolation of rainwater. Water balance covers rely on a less compacted soil “sponge” to store rainwater, and on soil evaporation and plant transpiration (evapotranspiration) to remove stored water and thereby limit percolation. Over time, natural soil-forming and ecological processes are changing conventional covers by increasing hydraulic conductivity, loosening compaction, and increasingmore » evapotranspiration. The rock armor on conventional covers creates a favorable habitat for vegetation by slowing soil evaporation, increasing soil water storage, and trapping dust and organic matter, thereby providing the water and nutrients needed for plant germination, survival, and sustainable transpiration. Goals and Objectives Our overall goal is to determine if allowing or enhancing these natural changes could improve cover performance and reduce maintenance costs over the long term. This test pad study focuses on cover soil hydrology and ecology. Companion studies are evaluating effects of natural and enhanced changes in covers on radon attenuation, erosion, and biointrusion. We constructed a test cover at the Grand Junction disposal site to evaluate soil manipulation and revegetation methods. The engineering design, construction, and properties of the test cover match the upper three layers of the nearby disposal cell cover: a 1-foot armoring of rock riprap, a 6-inch bedding layer of coarse sand and gravel, and a 2-foot protection layer of compacted fine soil. The test cover does not have a radon barrier—cover enhancement tests leave the radon barrier intact. We tested furrowing and ripping as means for creating depressions parallel to the slope contour, bringing soil up into the rock riprap layer, and loosening and blending compacted fine soil with coarse sand and gravel layers. Objectives of these manipulations include (1) enhancing root growth, (2) increasing seed-soil contact, (3) catching runoff water for plant germination and growth, (4) increasing soil water storage capacity, and (5) enhancing deep drying by disrupting the capillary barrier at the interface of the bedding and protection layers.« less

Field and laboratory procedures used in a soil chronosequence study

USGS Publications Warehouse

Singer, Michael J.; Janitzky, Peter

1986-01-01

In 1978, the late Denis Marchand initiated a research project entitled "Soil Correlation and Dating at the U.S. Geological Survey" to determine the usefulness of soils in solving geologic problems. Marchand proposed to establish soil chronosequences that could be dated independently of soil development by using radiometric and other numeric dating methods. In addition, by comparing dated chronosequences in different environments, rates of soil development could be studied and compared among varying climates and mineralogical conditions. The project was fundamental in documenting the value of soils in studies of mapping, correlating, and dating late Cenozoic deposits and in studying soil genesis. All published reports by members of the project are included in the bibliography.The project demanded that methods be adapted or developed to ensure comparability over a wide variation in soil types. Emphasis was placed on obtaining professional expertise and on establishing consistent techniques, especially for the field, laboratory, and data-compilation methods. Since 1978, twelve chronosequences have been sampled and analyzed by members of this project, and methods have been established and used consistently for analysis of the samples.The goals of this report are to:Document the methods used for the study on soil chronosequences,Present the results of tests that were run for precision, accuracy, and effectiveness, andDiscuss our modifications to standard procedures.Many of the methods presented herein are standard and have been reported elsewhere. However, we assume less prior analytical knowledge in our descriptions; thus, the manual should be easy to follow for the inexperienced analyst. Each chapter presents one or more references of the basic principle, an equipment and reagents list, and the detailed procedure. In some chapters this is followed by additional remarks or example calculations.The flow diagram in figure 1 outlines the step-by-step procedures used to obtain and analyze soil samples for this study. The soils analyzed had a wide range of characteristics (such as clay content, mineralogy, salinity, and acidity). Initially, a major task was to test and select methods that could be applied and interpreted similarly for the various types of soils. Tests were conducted to establish the effectiveness and comparability of analytical techniques, and the data for such tests are included in figures, tables, and discussions. In addition, many replicate analyses of samples have established a "standard error" or "coefficient of variance" which indicates the average reproducibility of each laboratory procedure. These averaged errors are reported as percentage of a given value. For example, in particle-size determination, 3 percent error for 10 percent clay content equals 10 ± 0.3 percent clay. The error sources were examined to determine, for example, if the error in particle-size determination was dependent on clay content. No such biases were found, and data are reported as percent error in the text and in tables of reproducibility.

Agronomic and environmental soil test phosphorus method comparisons and diet modification impacts on poultry litter phosphorus composition

NASA Astrophysics Data System (ADS)

Eugene, Branly

Phosphorus (P) loss from agricultural fields to freshwater ecosystems is of increasing concern due to elevated soil P levels brought on by long term and excessive application rates of manure and commercial fertilizers. Both Bray P1 and Mehlich-3 P (PM3) soil tests are used in Indiana to make fertilizer recommendations and to limit manure application rates. The Mehlich-3 P Saturation Ratio (PSRM3) has been proposed as an alternative to PM3 and the ammonium oxalate degree of P saturation (DPSOX) for assessing the risk of soluble P loss from soils. We assessed the correlations among agronomic soil test methods (PM3 and Bray P1), environmental soil test methods (soluble P: deionized water, DW; artificial rainwater, ARW; dilute salt extractable P, DSEP), ammonium oxalate P (POX), total P (TP), and P saturation methods from 565 Indiana surface soil samples. Significant correlations were found among the various STP methods evaluated, and Bray P1 and PM3 displayed the strongest coefficient of correlation (r = 0.93, p < 0.0001). Mehlich-3 P had stronger correlations with TP and POX compared to correlations between Bray P1 and TP and POX, and their correlations were all highly significant ( p < 0.0001). Additionally, all soluble P forms were significantly correlated with Bray P1, PM3, and POX, and the correlations between Bray P1 and all three soluble P measures were consistently greater than those between other soil test methods and the soluble measures. Significant correlations were found between PM3 and PSRM3 (r = 0.93, p < 0.0001) and between PSRM3 and DPSOX (r = 0.92, p < 0.0001), suggesting that PSRM3 can be as effective as DPSOX to identify soils with a greater potential to contribute bioavailable (not just soluble) P to surface and ground water. We conclude that both PM3 and PSRM3 can be integrated into more comprehensive P loss risk algorithms to mitigate elevated P concentration in surface and ground water. The PSRM3 can be used as an alternative to PM3 as it does account for extractable Al and Fe, the primary P sorbents in most soils. Although Bray P1 is an appropriate soil test based on the data generated in this study, it would not be the most practical soil test as it is not considered a multi-element extraction in most states. Since PM3 was strongly correlated with Bray P1 and the benefit of using PM3as a multi-element extractant from which the PSRM3 can be calculated, it is probably the most practical test to use for both agronomic and environmental soil P assessment. We also evaluated the impacts of diets containing different amounts of DDGS and dietary fumeric acid on P excretion and P transformations during litter storage. Total P and phytate P were significantly (p< 0.0001) affected by dietary inclusion of DDGS; where DDGS inclusion of 20% decreased TP by 16, 15, and 16% for day 0, 7, and 14 of storage, respectively compared to commercial diets. Phytate P, on the other hand, was reduced by 38, 37, and 47% for day 0, 7, and 14 of storage, respectively. Overall, DDGS influenced the forms of P in poultry litter with phytate P being the most impacted. The inclusion of DDGS in poultry diets seems promising as it can potentially decrease the levels of phytate P in poultry litters, which is of may be of environmental significance as phytate P can desorb inorganic P in soils.

40 CFR 265.112 - Closure plan; amendment of plan.

Code of Federal Regulations, 2010 CFR

2010-07-01

... residues and contaminated containment system components, equipment, structures, and soils during partial... contaminated soils, methods for sampling and testing surrounding soils, and criteria for determining the extent of decontamination necessary to satisfy the closure performance standard; and (5) A detailed...

40 CFR 264.112 - Closure plan; amendment of plan.

Code of Federal Regulations, 2010 CFR

2010-07-01

... residues and contaminated containment system components, equipment, structures, and soils during partial... contaminated soils, methods for sampling and testing surrounding soils, and criteria for determining the extent of decontamination required to satisfy the closure performance standard; and (5) A detailed...

Test procedure for determining organic matter content in soils : UV-VIS method.

DOT National Transportation Integrated Search

2010-11-01

The Texas Department of Transportation has been having problems with organic matter in soils that they : stabilize for use as subgrade layers in road construction. The organic matter reduces the effectiveness of : common soil additives (lime/cement) ...

Graphical determination of metal bioavailability to soil invertebrates utilizing the Langmuir sorption model

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

Donkin, S.G.

1997-09-01

A new method of performing soil toxicity tests with free-living nematodes exposed to several metals and soil types has been adapted to the Langmuir sorption model in an attempt at bridging the gap between physico-chemical and biological data gathered in the complex soil matrix. Pseudo-Langmuir sorption isotherms have been developed using nematode toxic responses (lethality, in this case) in place of measured solvated metal, in order to more accurately model bioavailability. This method allows the graphical determination of Langmuir coefficients describing maximum sorption capacities and sorption affinities of various metal-soil combinations in the context of real biological responses of indigenousmore » organisms. Results from nematode mortality tests with zinc, cadmium, copper, and lead in four soil types and water were used for isotherm construction. The level of agreement between these results and available literature data on metal sorption behavior in soils suggests that biologically relevant data may be successfully fitted to sorption models such as the Langmuir. This would allow for accurate prediction of soil contaminant concentrations which have minimal effect on indigenous invertebrates.« less

Usability of calcium carbide gas pressure method in hydrological sciences

NASA Astrophysics Data System (ADS)

Arsoy, S.; Ozgur, M.; Keskin, E.; Yilmaz, C.

2013-10-01

Soil moisture is a key engineering variable with major influence on ecological and hydrological processes as well as in climate, weather, agricultural, civil and geotechnical applications. Methods for quantification of the soil moisture are classified into three main groups: (i) measurement with remote sensing, (ii) estimation via (soil water balance) simulation models, and (iii) measurement in the field (ground based). Remote sensing and simulation modeling require rapid ground truthing with one of the ground based methods. Calcium carbide gas pressure (CCGP) method is a rapid measurement procedure for obtaining soil moisture and relies on the chemical reaction of the calcium carbide reagent with the water in soil pores. However, the method is overlooked in hydrological science applications. Therefore, the purpose of this study is to evaluate the usability of the CCGP method in comparison with standard oven-drying and dielectric methods in terms of accuracy, time efficiency, operational ease, cost effectiveness and safety for quantification of the soil moisture over a wide range of soil types. The research involved over 250 tests that were carried out on 15 different soil types. It was found that the accuracy of the method is mostly within ±1% of soil moisture deviation range in comparison to oven-drying, and that CCGP method has significant advantages over dielectric methods in terms of accuracy, cost, operational ease and time efficiency for the purpose of ground truthing.

Geophysical methods for monitoring soil stabilization processes

NASA Astrophysics Data System (ADS)

Saneiyan, Sina; Ntarlagiannis, Dimitrios; Werkema, D. Dale; Ustra, Andréa

2018-01-01

Soil stabilization involves methods used to turn unconsolidated and unstable soil into a stiffer, consolidated medium that could support engineered structures, alter permeability, change subsurface flow, or immobilize contamination through mineral precipitation. Among the variety of available methods carbonate precipitation is a very promising one, especially when it is being induced through common soil borne microbes (MICP - microbial induced carbonate precipitation). Such microbial mediated precipitation has the added benefit of not harming the environment as other methods can be environmentally detrimental. Carbonate precipitation, typically in the form of calcite, is a naturally occurring process that can be manipulated to deliver the expected soil strengthening results or permeability changes. This study investigates the ability of spectral induced polarization and shear-wave velocity for monitoring calcite driven soil strengthening processes. The results support the use of these geophysical methods as soil strengthening characterization and long term monitoring tools, which is a requirement for viable soil stabilization projects. Both tested methods are sensitive to calcite precipitation, with SIP offering additional information related to long term stability of precipitated carbonate. Carbonate precipitation has been confirmed with direct methods, such as direct sampling and scanning electron microscopy (SEM). This study advances our understanding of soil strengthening processes and permeability alterations, and is a crucial step for the use of geophysical methods as monitoring tools in microbial induced soil alterations through carbonate precipitation.

Application of spatial methods to identify areas with lime requirement in eastern Croatia

NASA Astrophysics Data System (ADS)

Bogunović, Igor; Kisic, Ivica; Mesic, Milan; Zgorelec, Zeljka; Percin, Aleksandra; Pereira, Paulo

2016-04-01

With more than 50% of acid soils in all agricultural land in Croatia, soil acidity is recognized as a big problem. Low soil pH leads to a series of negative phenomena in plant production and therefore as a compulsory measure for reclamation of acid soils is liming, recommended on the base of soil analysis. The need for liming is often erroneously determined only on the basis of the soil pH, because the determination of cation exchange capacity, the hydrolytic acidity and base saturation is a major cost to producers. Therefore, in Croatia, as well as some other countries, the amount of liming material needed to ameliorate acid soils is calculated by considering their hydrolytic acidity. For this research, several interpolation methods were tested to identify the best spatial predictor of hidrolitic acidity. The purpose of this study was to: test several interpolation methods to identify the best spatial predictor of hidrolitic acidity; and to determine the possibility of using multivariate geostatistics in order to reduce the number of needed samples for determination the hydrolytic acidity, all with an aim that the accuracy of the spatial distribution of liming requirement is not significantly reduced. Soil pH (in KCl) and hydrolytic acidity (Y1) is determined in the 1004 samples (from 0-30 cm) randomized collected in agricultural fields near Orahovica in eastern Croatia. This study tested 14 univariate interpolation models (part of ArcGIS software package) in order to provide most accurate spatial map of hydrolytic acidity on a base of: all samples (Y1 100%), and the datasets with 15% (Y1 85%), 30% (Y1 70%) and 50% fewer samples (Y1 50%). Parallel to univariate interpolation methods, the precision of the spatial distribution of the Y1 was tested by the co-kriging method with exchangeable acidity (pH in KCl) as a covariate. The soils at studied area had an average pH (KCl) 4,81, while the average Y1 10,52 cmol+ kg-1. These data suggest that liming is necessary agrotechnical measure for soil conditioning. The results show that ordinary kriging was most accurate univariate interpolation method with smallest error (RMSE) in all four data sets, while the least precise showed Radial Basis Functions (Thin Plate Spline and Inverse Multiquadratic). Furthermore, it is noticeable a trend of increasing errors (RMSE) with a reduced number of samples tested on the most accurate univariate interpolation model: 3,096 (Y1 100%), 3,258 (Y1 85%), 3,317 (Y1 70%), 3,546 (Y1 50%). The best-fit semivariograms show a strong spatial dependence in Y1 100% (Nugget/Sill 20.19) and Y1 85% (Nugget/Sill 23.83), while a further reduction of the number of samples resulted with moderate spatial dependence (Y1 70% -35,85% and Y1 50% - 32,01). Co-kriging method resulted in a reduction in RMSE compared with univariate interpolation methods for each data set with: 2,054, 1,731 and 1,734 for Y1 85%, Y1 70%, Y1 50%, respectively. The results show the possibility for reducing sampling costs by using co-kriging method which is useful from the practical viewpoint. Reduced number of samples by half for determination of hydrolytic acidity in the interaction with the soil pH provides a higher precision for variable liming compared to the univariate interpolation methods of the entire set of data. These data provide new opportunities to reduce costs in the practical plant production in Croatia.

Developing Soil Models for Dynamic Impact Simulations

NASA Technical Reports Server (NTRS)

Fasanella, Edwin L.; Lyle, Karen H.; Jackson, Karen E.

2009-01-01

This paper describes fundamental soils characterization work performed at NASA Langley Research Center in support of the Subsonic Rotary Wing (SRW) Aeronautics Program and the Orion Landing System (LS) Advanced Development Program (ADP). LS-DYNA(Registered TradeMark)1 soil impact model development and test-analysis correlation results are presented for: (1) a 38-ft/s vertical drop test of a composite fuselage section, outfitted with four blocks of deployable energy absorbers (DEA), onto sand, and (2) a series of impact tests of a 1/2-scale geometric boilerplate Orion capsule onto soil. In addition, the paper will discuss LS-DYNA contact analysis at the soil/structure interface, methods used to estimate frictional forces, and the sensitivity of the model to density, moisture, and compaction.

Comparative study of engineering properties of two-lime waste tire particle soil and soil with lime/loess ratio of 3:7

NASA Astrophysics Data System (ADS)

Tiecheng, Yan; Xingyuan, Zhang; Hongping, Yang

2018-03-01

This study describes an analytical comparison of the engineering characteristics of two-lime waste tire particle soil and soil with lime/loess ratio of 3:7 using density measurements, results of indoor consolidation tests, and direct shear tests to examine the strength and deformation characteristics. It investigates the engineering performance of collapsible loess treated with waste tire particles and lime. The results indicate that (1) the shear strength of the two-lime waste tire particle soils increases continuously with soil age; and (2) the two-lime waste tire particle soils are light-weight, strong, and low-deformation soils, and can be applied primarily to improve the foundation soil conditions in areas with collapsible loess soils. This could address the problem of used tire disposal, while providing a new method to consider and manage collapsible loess soils.

Terrestrial Eco-Toxicological Tests as Screening Tool to Assess Soil Contamination in Krompachy Area

NASA Astrophysics Data System (ADS)

Ol'ga, Šestinová; Findoráková, Lenka; Hančuľák, Jozef; Fedorová, Erika; Tomislav, Špaldon

2016-10-01

In this study, we present screening tool of heavy metal inputs to agricultural and permanent grass vegetation of the soils in Krompachy. This study is devoted to Ecotoxicity tests, Terrestrial Plant Test (modification of OECD 208, Phytotoxkit microbiotest on Sinapis Alba) and chronic tests of Earthworm (Dendrobaena veneta, modification of OECD Guidelines for the testing of chemicals 317, Bioaccumulation in Terrestrial Oligochaetes) as practical and sensitive screening method for assessing the effects of heavy metals in Krompachy soils. The total Cu, Zn, As, Pb and Hg concentrations and eco-toxicological tests of soils from the Krompachy area were determined of 4 sampling sites in 2015. An influence of the sampling sites distance from the copper smeltery on the absolutely concentrations of metals were recorded for copper, lead, zinc, arsenic and mercury. The highest concentrations of these metals were detected on the sampling sites up to 3 km from the copper smeltery. The samples of soil were used to assess of phytotoxic effect. Total mortality was established at earthworms using chronic toxicity test after 7 exposure days. The results of our study confirmed that no mortality was observed in any of the study soils. Based on the phytotoxicity testing, phytotoxic effects of the metals contaminated soils from the samples 3KR (7-9) S.alba seeds was observed.

Wavelet-based image analysis system for soil texture analysis

NASA Astrophysics Data System (ADS)

Sun, Yun; Long, Zhiling; Jang, Ping-Rey; Plodinec, M. John

2003-05-01

Soil texture is defined as the relative proportion of clay, silt and sand found in a given soil sample. It is an important physical property of soil that affects such phenomena as plant growth and agricultural fertility. Traditional methods used to determine soil texture are either time consuming (hydrometer), or subjective and experience-demanding (field tactile evaluation). Considering that textural patterns observed at soil surfaces are uniquely associated with soil textures, we propose an innovative approach to soil texture analysis, in which wavelet frames-based features representing texture contents of soil images are extracted and categorized by applying a maximum likelihood criterion. The soil texture analysis system has been tested successfully with an accuracy of 91% in classifying soil samples into one of three general categories of soil textures. In comparison with the common methods, this wavelet-based image analysis approach is convenient, efficient, fast, and objective.

Comparison of Shear-wave Profiles for a Compacted Fill in a Geotechnical Test Pit

NASA Astrophysics Data System (ADS)

Sylvain, M. B.; Pando, M. A.; Whelan, M.; Bents, D.; Park, C.; Ogunro, V.

2014-12-01

This paper investigates the use of common methods for geological seismic site characterization including: i) multichannel analysis of surface waves (MASW),ii) crosshole seismic surveys, and iii) seismic cone penetrometer tests. The in-situ tests were performed in a geotechnical test pit located at the University of North Carolina at Charlotte High Bay Laboratory. The test pit has dimensions of 12 feet wide by 12 feet long by 10 feet deep. The pit was filled with a silty sand (SW-SM) soil, which was compacted in lifts using a vibratory plate compactor. The shear wave velocity values from the 3 techniques are compared in terms of magnitude versus depth as well as spatially. The comparison was carried out before and after inducing soil disturbance at controlled locations to evaluate which methods were better suited to captured the induced soil disturbance.

Evaluation of a bioluminescence method, contact angle measurements and topography for testing the cleanability of plastic surfaces under laboratory conditions

NASA Astrophysics Data System (ADS)

Redsven, I.; Kymäläinen, H.-R.; Pesonen-Leinonen, E.; Kuisma, R.; Ojala-Paloposki, T.; Hautala, M.; Sjöberg, A.-M.

2007-04-01

Detection of adenosine triphosphate (ATP) by bioluminescence is used, for instance, in the food industry and in hospitals to assess the hygiene status of surfaces. The aim of this laboratory study was to investigate the feasibility of the ATP method for estimating the cleanability of resilient floor coverings from biological soil. The surfaces were worn using a Soiling and Wearing Drum Tester, and soiled and cleaned with an Erichsen Washability and Scrubbing Resistance Tester. In the laboratory test carried out with the bioluminescence method, most of the new and worn floor coverings that were biologically soiled were cleaned efficiently. According to this study, the semiquantitative ATP screening method can be used for hygiene monitoring of flooring materials. No correlation was found between cleanability and contact angles or surface topography measured using a profilometer. However, by revealing local irregularities and damage on surfaces, scanning electron micrographs appeared useful in explaining differences in cleanability.

How to interpret rheometry, an innovative technique in soil physicochemistry, correctly - explained by critical users

NASA Astrophysics Data System (ADS)

Holthusen, Dörthe; Paulus, Eloi; Pértile, Patricia; Reichert, José Miguel; José Reinert, Dalvan; Horn, Rainer

2015-04-01

In soil physics some new methods were developed in the past years, e.g. with regard to observe soil structure non-invasively by means of micro-computed tomography, while the range of methods that investigate a soil's behavior in motion, e.g. under the impact of mechanic stresses, was enlarged by rheometry. The adjustment to the specific conditions of soil as a relatively dry and heterogeneous media opened a new field compared to the materials under investigations till then, like concrete or clay dispersions. The potential of this methodology is not fully appreciated yet which we would like to change with the help of our findings and the deduced guidelines. Rheology itself has been making part of soil science already for many years; however, the technical investigation was mostly done at a large scale, by means of triaxial shear or shear frame or compression tests etc. The corresponding measuring device, the rheometer, hence was tested and developed by and for the industries of food, cosmetics, paintings and coatings and only quite recently found to be applicable to soil also. The most interesting aspect was the possibility to combine soil physics with soil chemistry, namely to relate the behavior of soil under mechanical stresses to chemical interactions like e.g. particle charge and friction between single particles by means of an amplitude sweep test. Meanwhile, many different soils of different texture, organic matter and oxides and hydroxides content, and fertilization levels have been investigated at different matric potentials and allowed for a comparatively broad classification system. Therewith, the microstructural stability of a given soil by means of stiffness degradation during an amplitude sweep test can be categorized as a function of texture and matric potential. The micro scale soil stability furthermore influences the processes and thus soil structural stability at larger scales, which supports the investigations of relationships between different scales. Transferability to field situations is given due to the character of the mechanic stress which equals those appearing e.g. under a tractor tire exerting vibrating, compressing and shearing forces. Unfortunately, the multiple results of this single test can impede the use of rheometry as their interpretation requires intensive data analysis. By pointing out the single results and their meaning for soil structure, we aim at facilitating the use of rheometry. We also suggest moderate alterations to take into account more strongly the vertical compression of soil for a more comprehensive implementation of a micro shear test. Additionally, we point out further uses of a rheometer in soil physics, which is the viscosity, i. e. the ability of a fluid to penetrate into a porous system and to be relocated within. Herewith, quite complex fluid characteristics, e.g. of animal manure, anaerobic digestates, but also pesticides in aqueous solution, root mucilage etc. can be determined and applied as improved, because more detailed, model parameters in soil water transport. As a conclusion, our contribution aims at further promoting a promising method for investigating the fundamentals of soil physics at the interface to soil chemistry.

Soil Compaction Assessment Using Spectral Analysis of Surface Waves (SASW)

NASA Astrophysics Data System (ADS)

Afiq Roslan, Muhammad; Madun, Aziman; Hazreek Zainalabidin, Mohd; Dan@Azlan, Mohd Firdaus Md; Khaidir Abu Talib, Mohd; Nur Hidayat Zahari, Muhammad; Ambak, Kamaruddin; Ashraf Mohamad Ismail, Mohd

2018-04-01

Compaction is a process of soil densification in earthworks via by pressing the soil particles with air being expelled from the soil mass, thereby increasing its unit weight. Thus, it is important to evaluate the quality of soil compaction as prescribed in the technical requirement. SASW method is widely used for estimating material properties in layered structures based on the dispersion characteristics of Rayleigh Waves. The small scale at dimension area of 1.0 m width x 1.0 m length x 0.9 m depth was excavated and back filled with laterite soil. The soil was compacted for every layer at 0.3 m thickness. Each layer of soil compaction was conducted compaction test using core cutter methods and SASW test to determine the density and shear wave velocity. The phase velocity for layer 1 was between 112 m/s and 114 m/s, layer 2 was between 67 m/s and 74 m/s and layer 3 was between 74 m/s and 97 m/s. The result shows that the compacted soil layers are not fulfilled the quality of compacted soil layers where supposedly the expected shear wave velocity for the compacted layers should be higher than 180 m/s which is classified as stiff soil.

Prediction of the wetting-induced collapse behaviour using the soil-water characteristic curve

NASA Astrophysics Data System (ADS)

Xie, Wan-Li; Li, Ping; Vanapalli, Sai K.; Wang, Jia-Ding

2018-01-01

Collapsible soils go through three distinct phases in response to matric suction decrease during wetting: pre-collapse phase, collapse phase and post-collapse phase. It is reasonable and conservative to consider a strain path that includes a pre-collapse phase in which constant volume is maintained and a collapse phase that extends to the final matric suction to be experienced by collapsible soils during wetting. Upon this assumption, a method is proposed for predicting the collapse behaviour due to wetting. To use the proposed method, two parameters, critical suction and collapse rate, are required. The former is the suction value below which significant collapse deformations take place in response to matric suction decease, and the later is the rate at which void ratio reduces with matric suction in the collapse phase. The value of critical suction can be estimated from the water-entry value taking account of both the microstructure characteristics and collapse mechanism of fine-grained collapsible soils; the wetting soil-water characteristic curve thus can be used as a tool. Five sets of data of wetting tests on both compacted and natural collapsible soils reported in the literature were used to validate the proposed method. The critical suction values were estimated from the water-entry value with parameter a that is suggested to vary between 0.10 and 0.25 for compacted soils and to be lower for natural collapsible soils. The results of a field permeation test in collapsible loess soils were also used to validate the proposed method. The relatively good agreement between the measured and estimated collapse deformations suggests that the proposed method can provide reasonable prediction of the collapse behaviour due to wetting.

DSM for soil erosion risk in Scotland

NASA Astrophysics Data System (ADS)

Poggio, Laura; Gimona, Alessandro; McLeaod, Jim; Castellazzi, Marie; Baggio Compagnucci, Andrea; Irvine, Justin

2017-04-01

Soils play a crucial role in ecosystem functioning, and modelling its risk of degradation is fundamental, especially in the context of climate change. In this work we used continuous 3D soil information derived from digital soil mapping (DSM) approaches to map sediment erosion and deposition patterns due to rainfall. The test area covers the whole of mainland Scotland, excluding the Northern Islands. Soil profiles data were interpolated using a geo-statistical hybrid Generalised Additive Models method for a range of soil properties such as organic matter, texture, soil depth and peat presence. The same method was used to interpolate climatic data and management information. Remote sensing data were integrated in the process and land use data included. Information on grazing (sheep and deer) pressure was taken into account in the modelling. The uncertainty was accounted and propagated across the whole process. The Scottish test case highlights the differences in roles between mineral and organic soils with an assessment adapted to each of them. The results and intermediate steps were compared with available continental scale results. The results show the importance of the use of DSM approaches for modeling soils and ecosystem functions and assessing uncertainty propagation.

Application of the digital image correlation method in the study of cohesive coarse soil deformations

NASA Astrophysics Data System (ADS)

Kogut, Janusz P.; Tekieli, Marcin

2018-04-01

Non-contact video measurement methods are used to extend the capabilities of standard measurement systems, based on strain gauges or accelerometers. In most cases, they are able to provide more accurate information about the material or construction being tested than traditional sensors, while maintaining a high resolution and measurement stability. With the use of optical methods, it is possible to generate a full field of displacement on the surface of the test sample. The displacement value is the basic (primary) value determined using optical methods, and it is possible to determine the size of the derivative in the form of a sample deformation. This paper presents the application of a non-contact optical method to investigate the deformation of coarse soil material. For this type of soil, it is particularly difficult to obtain basic strength parameters. The use of a non-contact optical method, followed by a digital image correlation (DIC) study of the sample obtained during the tests, effectively completes the description of the behaviour of this type of material.

Assessing the applicability of the earth impedance method for in situ studies of tree root systems

PubMed Central

Urban, Josef; Bequet, Raphael; Mainiero, Raphael

2011-01-01

Several electrical methods have been introduced as non-invasive techniques to overcome the limited accessibility to root systems. Among them, the earth impedance method (EIM) represents the most recent development. Applying an electrical field between a cormus and the rooted soil, the EIM measures the absorptive root surface area (ARSA) from grounding resistance patterns. Allometric relationships suggested that this method was a valuable tool. Crucial assumptions for the applicability of the EIM, however, have not been tested experimentally. Focusing on tree root systems, the present study assesses the applicability of the EIM. Six hypotheses, deduced from the EIM approach, were tested in several experiments and the results were compared with conventional methods. None of the hypotheses could be verified and the results allow two major conclusions. First, in terms of an analogue electrical circuit, a tree-root–soil continuum appears as a serial circuit with xylem and soil resistance being the dominant components. Allometric variation in contact resistance, with the latter being the proxy for root surface area, are thus overruled by the spatial and seasonal variation of soil and xylem resistances. Second, in a tree-root–soil continuum, distal roots conduct only a negligible portion of the electric charge. Most of charge carriers leave the root system in the proximal parts of the root–soil interface. PMID:21273337

Design and Construction of Airport Pavements on Expansive Soils

DTIC Science & Technology

1976-06-01

Selection of the type anc amount of stabilizing agent (lime, cement , asphalt, only) (4) Test methods to determine the physical properties of sta...7 8.3 5.4 3.3 6.5 1 4.7 3-3, 1 (8) Investigate the effect of sulfate on cement -stabilized soils and establish...terested because the properties of soil/ cement mixtures and the relationships existing among these properties and various test values are discussed

Soil aggregate stability within the morphologically diverse area

NASA Astrophysics Data System (ADS)

Jaksik, Ondrej; Kodesova, Radka; Kubis, Adam; Klement, Ales; Fer, Miroslav

2013-04-01

This study evaluates the effect of soil erosion on properties of topsoil especially on soil aggregate stability. Study was performed on morphologically diverse study site (6 ha area) in loess region of Southern Moravia, Czech Republic. The region has been under uninterrupted agricultural use since the middle of the Holocene. Haplic Chernozem is an original dominant soil unit in the area, nowadays progressively transformed into different soil units along with intensive soil erosion. There are eroded phases of Chernozem, Regosol (the steepest and heavily eroded parts of the study area), colluvial Chernozem and Colluvial soil (base slope). Sampling spots were selected in order to represent diverse soil units and morphological units. Soil samples were taken from the topsoil, carefully transported to the laboratory and consequently air dried. Following soil properties were measured: pH_KCl, pH_CaCl2, soil organic matter content (SOM), carbonate content (CO3), content of iron and manganese (in ammonium oxalate extract, Feo and Mn_o, and dithionite-citrate extract, Fed and Mn_d), and stability of soil aggregates using two different methods. The indexes of water stable aggregates (WSA) were determined using the procedure presented by Nimmo and Perkins (2002). The three methods proposed by Le Bissonnais (1996) were also used to study various destruction mechanisms. The fast wetting test (KV1) was applied to study aggregate slaking due to the compression of the entrapped air (mechanism similar to the WSA test). The slow wetting test (KV2) was used to evaluate aggregate disintegration caused by the micro cracking due to the different swelling, and physico-chemical dispersion due to the osmotic stress. The shaking after prewetting test (KV3) was utilized to study the mechanical aggregate breakdown. Terrain attributes were evaluated from digital terrain model. In general the lowest soil aggregate stability was observed on steep slopes, which were highly impacted by soil erosion. The highest aggregate stability was measured on soils sampled at relatively flat upper parts, which were only slightly influenced by erosion processes. Higher stability was also obtained on base slope, where the sedimentation of previously eroded soil material occurred. Following correlations were obtained between different test results: R=0.911 for WSA and KV1, R=0.481 for WSA and KV2, R=0.700 for WSA and KV3. The statistical significant correlation was found between WSA index and SOM (R=0.403), WSA and pH_CaCl2 (R=-0.360), WSA and Mnd (R=0.408), WSA and Mno (R=0.355), KV1 and SOM (R=-0.377), KV1 and pH_CaCl2 (R=0.352), KV2 and CO3 (R=0.379), KV3 and pH_CaCl2 (R=0.376). We also found statistical significant correlation between WSA index and two terrain attributes (plan curvature R=-0.490, and total curvature R=-0.501). Acknowledgment: Authors acknowledge the financial support of the Ministry of Agriculture of the Czech Republic (QJ1230319). References Le Bissonnais Y. 1996. Aggregate stability and assessment of soil crustability and erodibility: Theory and methodology. Eur. J. Soil Sci. 47: 425-437. Nimmo J.R., Perkins K.S. 2002. Aggregate stability and size distribution, pp. 317-328. In: Dane J. H. & Topp G.C. (eds), Methods of Soil Analysis, Part 4 - Physical Methods. Soil Science Society of America, Inc. Madison, USA.

Controlled soil warming powered by alternative energy for remote field sites.

PubMed

Johnstone, Jill F; Henkelman, Jonathan; Allen, Kirsten; Helgason, Warren; Bedard-Haughn, Angela

2013-01-01

Experiments using controlled manipulation of climate variables in the field are critical for developing and testing mechanistic models of ecosystem responses to climate change. Despite rapid changes in climate observed in many high latitude and high altitude environments, controlled manipulations in these remote regions have largely been limited to passive experimental methods with variable effects on environmental factors. In this study, we tested a method of controlled soil warming suitable for remote field locations that can be powered using alternative energy sources. The design was tested in high latitude, alpine tundra of southern Yukon Territory, Canada, in 2010 and 2011. Electrical warming probes were inserted vertically in the near-surface soil and powered with photovoltaics attached to a monitoring and control system. The warming manipulation achieved a stable target warming of 1.3 to 2 °C in 1 m(2) plots while minimizing disturbance to soil and vegetation. Active control of power output in the warming plots allowed the treatment to closely match spatial and temporal variations in soil temperature while optimizing system performance during periods of low power supply. Active soil heating with vertical electric probes powered by alternative energy is a viable option for remote sites and presents a low-disturbance option for soil warming experiments. This active heating design provides a valuable tool for examining the impacts of soil warming on ecosystem processes.

Interpretation of the lime column penetration test

NASA Astrophysics Data System (ADS)

Liyanapathirana, D. S.; Kelly, R. B.

2010-06-01

Dry soil mix (DSM) columns are used to reduce the settlement and to improve the stability of embankments constructed on soft clays. During construction the shear strength of the columns needs to be confirmed for compliance with technical assumptions. A specialized blade shaped penetrometer known as the lime column probe, has been developed for testing DSM columns. This test can be carried out as a pull out resistance test (PORT) or a push in resistance test (PIRT). The test is considered to be more representative of average column shear strength than methods that test only a limited area of the column. Both PORT and PIRT tests require empirical correlations of measured resistance to an absolute measure of shear strength, in a similar manner to the cone penetration test. In this paper, finite element method is used to assess the probe factor, N, for the PORT test. Due to the large soil deformations around the probe, an Arbitrary Lagrangian Eulerian (ALE) based finite element formulation has been used. Variation of N with rigidity index and the friction at the probe-soil interface are investigated to establish a range for the probe factor.

Test plan for the soils facility demonstration: A petroleum contaminated soil bioremediation facility

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

Lombard, K.H.

1994-08-01

The objectives of this test plan are to show the value added by using bioremediation as an effective and environmentally sound method to remediate petroleum contaminated soils (PCS) by: demonstrating bioremediation as a permanent method for remediating soils contaminated with petroleum products; establishing the best operating conditions for maximizing bioremediation and minimizing volatilization for SRS PCS during different seasons; determining the minimum set of analyses and sampling frequency to allow efficient and cost-effective operation; determining best use of existing site equipment and personnel to optimize facility operations and conserve SRS resources; and as an ancillary objective, demonstrating and optimizing newmore » and innovative analytical techniques that will lower cost, decrease time, and decrease secondary waste streams for required PCS assays.« less

Application of a new purification method of West-Kazakhstan chestnut soil microbiota DNA for metagenomic analysis

NASA Astrophysics Data System (ADS)

Sergaliev, N. Kh.; Kakishev, M. G.; Zhiengaliev, A. T.; Volodin, M. A.; Andronov, E. E.; Pinaev, A. G.

2015-04-01

A method for the extraction of soil microbial DNA has been tested on chestnut soils (Kastanozems) of the West Kazakhstan region. The taxonomic analysis of soil microbiome libraries has shown that the phyla Actinobacteria and Proteobacteria constitute the largest part of microbial communities in the analyzed soils. The Archaea form an appreciable part of the microbiome in the studied samples. In the underdeveloped dark chestnut soil, their portion is higher than 11%. This is of interest, as the proportion of Archaea in the soil communities of virgin lands usually does not exceed 5%. In addition to the phyla mentioned above, there are representatives of the phyla Acidobacteria, Bacteroidetes, Firmicutes, Gemmatimonadales, Planctomycetes, and Verrucomicrobia, which are all fairly common in soil communities.

Ultimate pier and contraction scour prediction in cohesive soils at selected bridges in Illinois

USGS Publications Warehouse

Straub, Timothy D.; Over, Thomas M.; Domanski, Marian M.

2013-01-01

The Scour Rate In COhesive Soils-Erosion Function Apparatus (SRICOS-EFA) method includes an ultimate scour prediction that is the equilibrium maximum pier and contraction scour of cohesive soils over time. The purpose of this report is to present the results of testing the ultimate pier and contraction scour methods for cohesive soils on 30 bridge sites in Illinois. Comparison of the ultimate cohesive and noncohesive methods, along with the Illinois Department of Transportation (IDOT) cohesive soil reduction-factor method and measured scour are presented. Also, results of the comparison of historic IDOT laboratory and field values of unconfined compressive strength of soils (Qu) are presented. The unconfined compressive strength is used in both ultimate cohesive and reduction-factor methods, and knowing how the values from field methods compare to the laboratory methods is critical to the informed application of the methods. On average, the non-cohesive method results predict the highest amount of scour, followed by the reduction-factor method results; and the ultimate cohesive method results predict the lowest amount of scour. The 100-year scour predicted for the ultimate cohesive, noncohesive, and reduction-factor methods for each bridge site and soil are always larger than observed scour in this study, except 12% of predicted values that are all within 0.4 ft of the observed scour. The ultimate cohesive scour prediction is smaller than the non-cohesive scour prediction method for 78% of bridge sites and soils. Seventy-six percent of the ultimate cohesive predictions show a 45% or greater reduction from the non-cohesive predictions that are over 10 ft. Comparing the ultimate cohesive and reduction-factor 100-year scour predictions methods for each bridge site and soil, the scour predicted by the ultimate cohesive scour prediction method is less than the reduction-factor 100-year scour prediction method for 51% of bridge sites and soils. Critical shear stress remains a needed parameter in the ultimate scour prediction for cohesive soils. The unconfined soil compressive strength measured by IDOT in the laboratory was found to provide a good prediction of critical shear stress, as measured by using the erosion function apparatus in a previous study. Because laboratory Qu analyses are time-consuming and expensive, the ability of field-measured Rimac data to estimate unconfined soil strength in the critical shear–soil strength relation was tested. A regression analysis was completed using a historic IDOT dataset containing 366 data pairs of laboratory Qu and field Rimac measurements from common sites with cohesive soils. The resulting equations provide a point prediction of Qu, given any Rimac value with the 90% confidence interval. The prediction equations are not significantly different from the identity Qu = Rimac. The alternative predictions of ultimate cohesive scour presented in this study assume Qu will be estimated using Rimac measurements that include computed uncertainty. In particular, the ultimate cohesive predicted scour is greater than observed scour for the entire 90% confidence interval range for predicting Qu at the bridges and soils used in this study, with the exception of the six predicted values that are all within 0.6 ft of the observed scour.

Acid-base properties of water-soluble organic matter of forest soils, studied by the pK-spectroscopy method.

PubMed

Shamrikova, E V; Ryazanov, M A; Vanchikova, E V

2006-11-01

Using the potentiometric titration and pK spectroscopy method, acid-base properties of water-soluble organic matter of forest soils have been studied. Five acidic classes composed of different substances with pK(a) values around 3.6; 4.8; 6.7; 8.7 and 9.7 have been identified. Testing the properties of soluble soil fraction, it is to be taken into account that when it is isolated from non-soluble soil matter, some water-soluble substances remain in soil and do not pass into the solution. Most firmly adsorbed in soil are water-soluble components with pK(a) 9.6-9.8.

Impacts of heterogeneous organic matter on phenanthrene sorption--Different soil and sediment samples

USGS Publications Warehouse

Karapanagioti, Hrissi K.; Childs, Jeffrey; Sabatini, David A.

2001-01-01

Organic petrography has been proposed as a tool for characterizing the heterogeneous organic matter present in soil and sediment samples. A new simplified method is proposed as a quantitative means of interpreting observed sorption behavior for phenanthrene and different soils and sediments based on their organic petrographical characterization. This method is tested under singe solute conditions and at phenanthrene concentration of 1 μg/L. Since the opaque organic matter fraction dominates the sorption process, we propose that by quantifying this fraction one can interpret organic content normalized sorption distribution coefficient (Koc) values for a sample. While this method was developed and tested for various samples within the same aquifer, in the current study the method is validated for soil and sediment samples from different sites that cover a wide range of organic matter origin, age, and organic content. All 10 soil and sediment samples studied had log Koc values for the opaque particles between 5.6 and 6.8. This range of Koc values illustrates the heterogeneity of opaque particles between sites and geological formations and thus the need to characterize the opaque fraction of materials on a site-by-site basis.

78 FR 45104 - Model Manufactured Home Installation Standards: Ground Anchor Installations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-26

... test methods for establishing working load design values of ground anchor assemblies used for new... anchor installations and establish standardized test methods to determine ground anchor performance and... currently no national test method for rating and certifying ground anchor assemblies in different soil...

Contribution of calcium oxalate to soil-exchangeable calcium

USGS Publications Warehouse

Dauer, Jenny M.; Perakis, Steven S.

2013-01-01

Acid deposition and repeated biomass harvest have decreased soil calcium (Ca) availability in many temperate forests worldwide, yet existing methods for assessing available soil Ca do not fully characterize soil Ca forms. To account for discrepancies in ecosystem Ca budgets, it has been hypothesized that the highly insoluble biomineral Ca oxalate might represent an additional soil Ca pool that is not detected in standard measures of soil-exchangeable Ca. We asked whether several standard method extractants for soil-exchangeable Ca could also access Ca held in Ca oxalate crystals using spike recovery tests in both pure solutions and soil extractions. In solutions of the extractants ammonium chloride, ammonium acetate, and barium chloride, we observed 2% to 104% dissolution of Ca oxalate crystals, with dissolution increasing with both solution molarity and ionic potential of cation extractant. In spike recovery tests using a low-Ca soil, we estimate that 1 M ammonium acetate extraction dissolved sufficient Ca oxalate to contribute an additional 52% to standard measurements of soil-exchangeable Ca. However, in a high-Ca soil, the amount of Ca oxalate spike that would dissolve in 1 M ammonium acetate extraction was difficult to detect against the large pool of exchangeable Ca. We conclude that Ca oxalate can contribute substantially to standard estimates of soil-exchangeable Ca in acid forest soils with low soil-exchangeable Ca. Consequently, measures of exchangeable Ca are unlikely to fully resolve discrepancies in ecosystem Ca mass balance unless the contribution of Ca oxalate to exchangeable Ca is also assessed.

Recovery of microbial community structure and functioning after wildfire in semi-arid environments: optimising methods for monitoring and assessment

NASA Astrophysics Data System (ADS)

Muñoz-Rojas, Miriam; Martini, Dylan; Erickson, Todd; Merritt, David; Dixon, Kingsley

2015-04-01

Introduction In semi-arid areas such as northern Western Australia, wildfires are a natural part of the environment and many ecosystems in these landscapes have evolved and developed a strong relationship with fire. Soil microbial communities play a crucial role in ecosystem processes by regulating the cycling of nutrients via decomposition, mineralization, and immobilization processes. Thus, the structure (e.g. soil microbial biomass) and functioning (e.g. soil microbial activity) of microbial communities, as well as their changes after ecosystem disturbance, can be useful indicators of soil quality and health recovery. In this research, we assess the impacts of fire on soil microbial communities and their recovery in a biodiverse semi-arid environment of Western Australia (Pilbara region). New methods for determining soil microbial respiration as an indicator of microbial activity and soil health are also tested. Methodology Soil samples were collected from 10 similar ecosystems in the Pilbara with analogous native vegetation, but differing levels of post-fire disturbance (i.e. 3 months, 1 year, 5, 7 and 14 years after wildfire). Soil microbial activity was measured with the Solvita test which determines soil microbial respiration rate based on the measurement of the CO2 burst of a dry soil after it is moistened. Soils were dried and re-wetted and a CO2 probe was inserted before incubation at constant conditions of 25°C during 24 h. Measurements were taken with a digital mini spectrometer. Microbial (bacteria and fungi) biomass and community composition were measured by phospholipid fatty acid analysis (PLFA). Results Immediately after the fire (i.e. 3 months), soil microbial activity and microbial biomass are similar to 14 years 'undisturbed' levels (53.18±3.68 ppm CO2-CO and 14.07±0.65 mg kg-1, respectively). However, after the first year post-fire, with larger plant productivity, microbial biomass and microbial activity increase rapidly, peaking after 5-7 years post fire (70.70±8.94 ppm CO2-CO and 21.67±2.62 mg kg-1, respectively). Microbial activity measured with the Solvita test was significantly correlated (R Pearson > 0.7; P < 0.001) with microbial parameters analysed with PLFA such as microbial biomass, bacteria biomass or mycorrhizhal fungi. This method has proven to be reliable, fast and easy to interpret for assessment of soil microbial activity in the recovery of soil quality during the recovery after fire. Keywords Pilbara region, biodiverse ecosystems, microbial biomass, microbial respiration, Solvita test, CO2 burst.

Assessing NIR & MIR Spectral Analysis as a Method for Soil C Estimation Across a Network of Sampling Sites

NASA Astrophysics Data System (ADS)

Spencer, S.; Ogle, S.; Borch, T.; Rock, B.

2008-12-01

Monitoring soil C stocks is critical to assess the impact of future climate and land use change on carbon sinks and sources in agricultural lands. A benchmark network for soil carbon monitoring of stock changes is being designed for US agricultural lands with 3000-5000 sites anticipated and re-sampling on a 5- to10-year basis. Approximately 1000 sites would be sampled per year producing around 15,000 soil samples to be processed for total, organic, and inorganic carbon, as well as bulk density and nitrogen. Laboratory processing of soil samples is cost and time intensive, therefore we are testing the efficacy of using near-infrared (NIR) and mid-infrared (MIR) spectral methods for estimating soil carbon. As part of an initial implementation of national soil carbon monitoring, we collected over 1800 soil samples from 45 cropland sites in the mid-continental region of the U.S. Samples were processed using standard laboratory methods to determine the variables above. Carbon and nitrogen were determined by dry combustion and inorganic carbon was estimated with an acid-pressure test. 600 samples are being scanned using a bench- top NIR reflectance spectrometer (30 g of 2 mm oven-dried soil and 30 g of 8 mm air-dried soil) and 500 samples using a MIR Fourier-Transform Infrared Spectrometer (FTIR) with a DRIFT reflectance accessory (0.2 g oven-dried ground soil). Lab-measured carbon will be compared to spectrally-estimated carbon contents using Partial Least Squares (PLS) multivariate statistical approach. PLS attempts to develop a soil C predictive model that can then be used to estimate C in soil samples not lab-processed. The spectral analysis of soil samples either whole or partially processed can potentially save both funding resources and time to process samples. This is particularly relevant for the implementation of a national monitoring network for soil carbon. This poster will discuss our methods, initial results and potential for using NIR and MIR spectral approaches to either replace or augment traditional lab-based carbon analyses of soils.

Spatial probability of soil water repellency in an abandoned agricultural field in Lithuania

NASA Astrophysics Data System (ADS)

Pereira, Paulo; Misiūnė, Ieva

2015-04-01

Water repellency is a natural soil property with implications on infiltration, erosion and plant growth. It depends on soil texture, type and amount of organic matter, fungi, microorganisms, and vegetation cover (Doerr et al., 2000). Human activities as agriculture can have implications on soil water repellency (SWR) due tillage and addition of organic compounds and fertilizers (Blanco-Canqui and Lal, 2009; Gonzalez-Penaloza et al., 2012). It is also assumed that SWR has a high small-scale variability (Doerr et al., 2000). The aim of this work is to study the spatial probability of SWR in an abandoned field testing several geostatistical methods, Organic Kriging (OK), Simple Kriging (SK), Indicator Kriging (IK), Probability Kriging (PK) and Disjunctive Kriging (DK). The study area it is located near Vilnius urban area at (54 49' N, 25 22', 104 masl) in Lithuania (Pereira and Oliva, 2013). It was designed a experimental plot with 21 m2 (07x03 m). Inside this area it was measured SWR was measured every 50 cm using the water drop penetration time (WDPT) (Wessel, 1998). A total of 105 points were measured. The probability of SWR was classified in 0 (No probability) to 1 (High probability). The methods accuracy was assessed with the cross validation method. The best interpolation method was the one with the lowest Root Mean Square Error (RMSE). The results showed that the most accurate probability method was SK (RMSE=0.436), followed by DK (RMSE=0.437), IK (RMSE=0.448), PK (RMSE=0.452) and OK (RMSE=0.537). Significant differences were identified among probability tests (Kruskal-Wallis test =199.7597 p<0.001). On average the probability of SWR was high with the OK (0.58±0.08) followed by PK (0.49±0.18), SK (0.32±0.16), DK (0.32±0.15) and IK (0.31±0.16). The most accurate probability methods predicted a lower probability of SWR in the studied plot. The spatial distribution of SWR was different according to the tested technique. Simple Kriging, DK, IK and PK methods identified the high SWR probabilities in the northeast and central part of the plot, while OK observed mainly in the south-western part of the plot. In conclusion, before predict the spatial probability of SWR it is important to test several methods in order to identify the most accurate. Acknowledgments COST action ES1306 (Connecting European connectivity research). References Blanco-Canqui, H., Lal, R. (2009) Extend of water repellency under long-term no-till soils. Geoderma, 149, 171-180. Doerr, S.H., Shakesby, R.A., Walsh, R.P.D. (2000) Soil water repellency: Its causes, characteristics and hydro-geomorphological significance. Earth-Science Reviews, 51, 33-65. Gonzalez-Penaloza, F.A., Cerda, A., Zavala, L.M., Jordan, A., Gimenez-Morera, A., Arcenegui, V. (2012) Do conservative agriculture practices increase soil water repellency? A case study in citrus-croped soils. Soil and Tillage Research, 124, 233-239. Pereira, P., Oliva, M. (2013) Modelling soil water repellency in an abandoned agricultural field, Visnyk Geology, Visnyk Geology 4, 77-80. Wessel, A.T. (1988) On using the effective contact angle and the water drop penetration time for classification of water repellency in dune soils. Earth Surface Process and Landforms, 13, 555-265.

Evaluating the importance of characterizing soil structure and horizons in parameterizing a hydrologic process model

USGS Publications Warehouse

Mirus, Benjamin B.

2015-01-01

Incorporating the influence of soil structure and horizons into parameterizations of distributed surface water/groundwater models remains a challenge. Often, only a single soil unit is employed, and soil-hydraulic properties are assigned based on textural classification, without evaluating the potential impact of these simplifications. This study uses a distributed physics-based model to assess the influence of soil horizons and structure on effective parameterization. This paper tests the viability of two established and widely used hydrogeologic methods for simulating runoff and variably saturated flow through layered soils: (1) accounting for vertical heterogeneity by combining hydrostratigraphic units with contrasting hydraulic properties into homogeneous, anisotropic units and (2) use of established pedotransfer functions based on soil texture alone to estimate water retention and conductivity, without accounting for the influence of pedon structures and hysteresis. The viability of this latter method for capturing the seasonal transition from runoff-dominated to evapotranspiration-dominated regimes is also tested here. For cases tested here, event-based simulations using simplified vertical heterogeneity did not capture the state-dependent anisotropy and complex combinations of runoff generation mechanisms resulting from permeability contrasts in layered hillslopes with complex topography. Continuous simulations using pedotransfer functions that do not account for the influence of soil structure and hysteresis generally over-predicted runoff, leading to propagation of substantial water balance errors. Analysis suggests that identifying a dominant hydropedological unit provides the most acceptable simplification of subsurface layering and that modified pedotransfer functions with steeper soil-water retention curves might adequately capture the influence of soil structure and hysteresis on hydrologic response in headwater catchments.

Effects of Applied Land Use Strategies on Farmland Soils in the Southwestern Siberian Kulunda-Steppe

NASA Astrophysics Data System (ADS)

Grunwald, Lars-Christian; Illiger, Patrick; Stephan, Eckart; Frühauf, Manfred

2014-05-01

The Kulunda steppe in southwestern Siberia is one of the most intensely used agricultural regions in the world. The study area of the KULUNDA project is the Kulunda steppe, which is a part of the conversion region created during the so called "virgin land campaign" in the soviet era. Nowadays it is characterized by widespread soil degradation. Despite the fact that agriculture is the basis of existence, land use practice is maladjusted to the local conditions. The widespread soil degradation and accordingly the decreased soil humus content have negative effects on crop yields in this region. With respect to climate change, the current study analyses the cause effect relationship between land use practice and soil properties. In particular, different methods of soil cultivation will be tested and for each of the cases the soil humus content, soil water, soil solute balance will be measured and compared. In addition, the possibilities of soil carbon sequestration capacity will be analyzed. Furthermore, the study aims to achieve properly adapted sustainable cropping systems to stabilize the yields and to increase the productivity of plant production per spatial unit in this high vulnerable dry farming region. In 2012 the long term field trials started at three test farms in different steppe biomes, containing different soil types from chernozems to kastanozems. Each of them is characterized by a negative water balance. Successfully running cropping models, such as crop rotation, tilling intensity, plant protection and nutrition strategies from south Canadian steppe regions were adapted to regional agronomic needs. The traditional Russian cultivation system will be compared with two modern systems, including no-tillage methods on specially randomized test plots. Additionally, these plots are equipped with soil moisture monitoring systems to analyze the soil water content in different depths under the different cropping methods. The expected results will not only deepen the understanding of the impact of agricultural land use practice on field scale, but also largely contribute to the research on sustainable land management, rural development and climate change and connect applied science with capacity building for local stakeholders.

Soil carbon content and character in an old-growth forest in northwestern Pennsylvania: a case study introducing pyrolysis molecular beam mass spectrometry (py-MBMS)

Treesearch

C.M. Hoover; K.A. Magrini; R.J. Evans

2002-01-01

This study was conducted to: (1) test the utility of a new and rapid analytical method, pyrolysis molecular beam mass spectrometry (py-MBMS), for the measurement and characterization of carbon in forest soils, and (2) examine the effects of natural disturbance on soil carbon dynamics. An additional objective was to test the ability of py-MBMS to distinguish recent from...

Evaluation of PLS, LS-SVM, and LWR for quantitative spectroscopic analysis of soils

USDA-ARS?s Scientific Manuscript database

Soil testing requires the analysis of large numbers of samples in laboratory that are often time consuming and expensive. Mid-infrared spectroscopy (mid-IR) and near-infrared spectroscopy (NIRS) are fast, non-destructive, and inexpensive analytical methods that have been used for soil analysis, in l...

Microfungi diversity isolation from sandy soil of Acapulco touristic beaches

USDA-ARS?s Scientific Manuscript database

Microscopic fungi diversity in marine sandy soil habitats is associated with key functions of beach ecosystems. There are few reports on their presence in Mexican beaches. Although standard methods to obtain the fungi from soil samples are established, the aim of this pilot study was to test the pla...

Quantification of soil surface roughness evolution under simulated rainfall

USDA-ARS?s Scientific Manuscript database

Soil surface roughness is commonly identified as one of the dominant factors governing runoff and interrill erosion. The objective of this study was to compare several existing soil surface roughness indices and to test the Revised Triangular Prism surface area Method (RTPM) as a new approach to cal...

Critical assessment of jet erosion test methodologies for cohesive soil and sediment

USDA-ARS?s Scientific Manuscript database

The submerged Jet Erosion Test (JET) is a commonly used technique to assess the erodibility of cohesive soil. Employing a linear excess shear stress equation and impinging jet theory, simple numerical methods have been developed to analyze data collected using a JET to determine the critical shear s...

Implementation of the soil compactor analyzer into test method TEX-113-E : technical report.

DOT National Transportation Integrated Search

2012-04-01

Test method Tex-113-E prepares laboratory aggregate base test specimens with an impact hammer : compactor. These specimens are used for compaction characteristics and design tests. Although the : historical Tex-113-E required a certain amount of comp...

Testing an Alternative Method for Estimating the Length of Fungal Hyphae Using Photomicrography and Image Processing.

PubMed

Shen, Qinhua; Kirschbaum, Miko U F; Hedley, Mike J; Camps Arbestain, Marta

2016-01-01

This study aimed to develop and test an unbiased and rapid methodology to estimate the length of external arbuscular mycorrhizal fungal (AMF) hyphae in soil. The traditional visual gridline intersection (VGI) method, which consists in a direct visual examination of the intersections of hyphae with gridlines on a microscope eyepiece after aqueous extraction, membrane-filtration, and staining (e.g., with trypan blue), was refined. For this, (i) images of the stained hyphae were taken by using a digital photomicrography technique to avoid the use of the microscope and the method was referred to as "digital gridline intersection" (DGI) method; and (ii), the images taken in (i) were processed and the hyphal length was measured by using ImageJ software, referred to as the "photomicrography-ImageJ processing" (PIP) method. The DGI and PIP methods were tested using known grade lengths of possum fur. Then they were applied to measure the hyphal lengths in soils with contrasting phosphorus (P) fertility status. Linear regressions were obtained between the known lengths (Lknown) of possum fur and the values determined by using either the DGI (LDGI) (LDGI = 0.37 + 0.97 × Lknown, r2 = 0.86) or PIP (LPIP) methods (LPIP = 0.33 + 1.01 × Lknown, r2 = 0.98). There were no significant (P > 0.05) differences between the LDGI and LPIP values. While both methods provided accurate estimation (slope of regression being 1.0), the PIP method was more precise, as reflected by a higher value of r2 and lower coefficients of variation. The average hyphal lengths (6.5-19.4 m g-1) obtained by the use of these methods were in the range of those typically reported in the literature (3-30 m g-1). Roots growing in P-deficient soil developed 2.5 times as many hyphae as roots growing in P-rich soil (17.4 vs 7.2 m g-1). These tests confirmed that the use of digital photomicrography in conjunction with either the grid-line intersection principle or image processing is a suitable method for the measurement of AMF hyphal lengths in soils for comparative investigations.

[Change in soil enzymes activities after adding biochar or straw by fluorescent microplate method].

PubMed

Zhang, Yu-Lan; Chen, Li-Jun; Duan, Zheng-Hu; Wu, Zhi-Jie; Sun, Cai-Xia; Wang, Jun-Yu

2014-02-01

The present work was aimed to study soil a-glucosidase and beta-glucosidase activities of and red soils based on fluorescence detection method combined with 96 microplates with TECAN Infinite 200 Multi-Mode Microplate Reader. We added biochar or straw (2.5 g air dry sample/50g air dry soil sample) into and red soils and the test was carried under fixed temperature and humidity condition (25 degrees C, 20% soil moisture content). The results showed that straw addition enhances soil alpha-glucosidase and beta-glucosidase activities, beta-glucosidase activity stimulated by rice straw treatment was higher than that of corn straw treatment, and activity still maintains strong after 40 days, accounting for increasing soil carbon transformation with straw inputting. Straw inputting increased soil nutrients contents and may promote microbial activity, which also lead to the increase oin enzyme Straw inputting increased soil nutrients contents and may promote microbial activity, which also lead to the increase oin enzyme activities. Different effects of straw kinds may be related to material source that needs further research. However, biochar inputting has little effect on soil alpha-glucosidase and beta-glucosidase activity. Biochar contains less available nutrients than straw and have degradation-resistant characteristics. Compared with the conventional spectrophotometric method, fluorescence microplate method is more sensitive to soil enzyme activities in suspension liquid, which can be used in a large number of samples. In brief, fluorescence microplate method is fast, accurate, and simple to determine soil enzymes activities.

In situ stabilization of cadmium-, lead-, and zinc-contaminated soil using various amendments.

PubMed

Lee, Sang-Hwan; Lee, Jin-Soo; Choi, Youn Jeong; Kim, Jeong-Gyu

2009-11-01

Chemical stabilization is an in situ remediation method that uses inexpensive amendments to reduce contaminant availability in polluted soil. We tested the effects of several amendments (limestone, red-mud, and furnace slag) on the extractability of heavy metals, microbial activities, phytoavailability of soil metals (assessed using lettuce, Lactuca sativa L.), and availability of heavy metals in ingested soil to the human gastrointestinal system (assessed using the physiologically based extraction test). The application of soil amendments significantly decreased the amount of soluble and extractable heavy metals in the soil (p<0.05). The decreased extractable metal content of soil was accompanied by increased microbial activity and decreased plant uptake of heavy metals. Soil microbial activities (soil respiration, urease, and dehydrogenase activity) significantly increased in limestone and red-mud-amended soils. Red-mud was the most effective treatment in decreasing heavy-metal concentrations in lettuce. Compared to non-amended control soil, lettuce uptake of Cd, Pb, and Zn was reduced 86%, 58%, and 73%, respectively, by the addition of red-mud.

The Influence of Processing Soil With a Coffee Grinder on Soil Classification

DTIC Science & Technology

2015-01-20

shaker, sieves , coffee grinder, plastic limit tool, bowls, spatulas, and scoops. To classify soils, a dry sieve analysis is performed, as is a Plastic...processed with the coffee grinder for 90 seconds as described above. Sieve analysis using the wet preparation method was used to test and classify the soils...one 90 second cycle of Elevator Soil Figure 3: The blades after three 90 second cycles of Elevator Soil 71Page 4.2 Ottawa Sand Dry Sieve Analysis

Optimization of the diffusive gradients in thin films (DGT) method for simultaneous assay of potassium and plant-available phosphorus in soils.

PubMed

Zhang, Yulin; Mason, Sean; McNeill, Ann; McLaughlin, Michael J

2013-09-15

Potassium (K) and phosphorus (P) are two important macronutrients for crops, and are usually applied to soils as granular fertilizer before seeding. Therefore, accurate soil tests prior to planting to predict crop response to fertilizers are important in optimizing crop yields. Traditional methods used for testing both available K and P in soils, which are based on chemical extraction procedures, are to be soil-type dependent, and the predictive relationships across a broad range of soils are generally poor. The diffusive gradients in thin films (DGT) technique, based on diffusion theory, is extensively used to measure the diffusive supply of trace elements, metals and some nutrients in soils and water. When DGT is used to assess plant-available P in soils, a good relationship is found between crop response to P fertilizer and concentrations of P in soil measured by DGT, and therefore the DGT method provides a more precise recommendation of P fertilizer requirements. Adaptation of the DGT method to measure plant-available K in soils has already been attempted [1], but limitations were reported due to the non-uniform size of the resin gel, decreased K binding rate of the gel at long deployment times and a limited ability to measure a wide range of K concentrations. To eliminate these problems, a new resin gel has been developed by combining Amberlite and ferrihydrite. This mixed Amberlite and ferrihydrite (MAF) gel has improved properties in terms of handling and even distribution of Amberlite in the gel. The elution efficiencies of the MAF gel for K and P were 90% and 96%, respectively. The diffusion coefficient of K through the diffusive gel was 1.30 × 10(-5)cm(2)s(-1) at 22 ± 1°C and was stable through time. Since ferrihydrite is already used in DGT P testing, the ability of the MAF gel to assess available P simultaneously was also assessed. The MAF gel performed the same as the traditional ferrihydrite gel for available P assessment in a wide variety of agricultural soils. This means that the newly developed gel has the potential to measure K and plant-available P in soils simultaneously. Copyright © 2013 Elsevier B.V. All rights reserved.

Recovery of soil unicellular eukaryotes: an efficiency and activity analysis on the single cell level.

PubMed

Lentendu, Guillaume; Hübschmann, Thomas; Müller, Susann; Dunker, Susanne; Buscot, François; Wilhelm, Christian

2013-12-01

Eukaryotic unicellular organisms are an important part of the soil microbial community, but they are often neglected in soil functional microbial diversity analysis, principally due to the absence of specific investigation methods in the special soil environment. In this study we used a method based on high-density centrifugation to specifically isolate intact algal and yeast cells, with the aim to analyze them with flow cytometry and sort them for further molecular analysis such as deep sequencing. Recovery efficiency was tested at low abundance levels that fit those in natural environments (10(4) to 10(6) cells per g soil). Five algae and five yeast morphospecies isolated from soil were used for the testing. Recovery efficiency was between 1.5 to 43.16% and 2 to 30.2%, respectively, and was dependent on soil type for three of the algae. Control treatments without soil showed that the majority of cells were lost due to the method itself (58% and 55.8% respectively). However, the cell extraction technique did not much compromise cell vitality because a fluorescein di-acetate assay indicated high viability percentages (73.3% and 97.2% of cells, respectively). The low abundant algae and yeast morphospecies recovered from soil were cytometrically analyzed and sorted. Following, their DNA was isolated and amplified using specific primers. The developed workflow enables isolation and enrichment of intact autotrophic and heterotrophic soil unicellular eukaryotes from natural environments for subsequent application of deep sequencing technologies. Copyright © 2013 Elsevier B.V. All rights reserved.

Critical Evaluation of Soil Pore Water Extraction Methods on a Natural Soil

NASA Astrophysics Data System (ADS)

Orlowski, Natalie; Pratt, Dyan; Breuer, Lutz; McDonnell, Jeffrey

2017-04-01

Soil pore water extraction is an important component in ecohydrological studies for the measurement of δ2H and δ18O. The effect of pore water extraction technique on resultant isotopic signature is poorly understood. Here we present results of an intercomparison of commonly applied lab-based soil water extraction techniques on a natural soil: high pressure mechanical squeezing, centrifugation, direct vapor equilibration, microwave extraction, and two types of cryogenic extraction systems. We applied these extraction methods to a natural summer-dry (gravimetric water contents ranging from 8% to 15%) glacio-lacustrine, moderately fine textured clayey soil; excavated in 10 cm sampling increments to a depth of 1 meter. Isotope results were analyzed via OA-ICOS and compared for each extraction technique that produced liquid water. From our previous intercomparison study among the same extraction techniques but with standard soils, we discovered that extraction methods are not comparable. We therefore tested the null hypothesis that all extraction techniques would be able to replicate the natural evaporation front in a comparable manner occurring in a summer-dry soil. Our results showed that the extraction technique utilized had a significant effect on the soil water isotopic composition. High pressure mechanical squeezing and vapor equilibration techniques produced similar results with similarly sloped evaporation lines. Due to the nature of soil properties and dryness, centrifugation was unsuccessful in obtaining pore water for isotopic analysis. Cryogenic extraction on both tested techniques produced similar results to each other on a similar sloping evaporation line, but dissimilar with depth.

Synergistic method for boreal soil moisture and soil freeze retrievals using active and passive microwave instruments

NASA Astrophysics Data System (ADS)

Smolander, Tuomo; Lemmetyinen, Juha; Rautiainen, Kimmo; Schwank, Mike; Pulliainen, Jouni

2017-04-01

Soil moisture and soil freezing are important for diverse hydrological, biogeochemical, and climatological applications. They affect surface energy balance, surface and subsurface water flow, and exchange rates of carbon with the atmosphere. Soil freezing controls important biogeochemical processes, like photosynthetic activity of plants and microbial activity within soils. Permafrost covers approximately 24% of the land surface in the Northern Hemisphere and seasonal freezing occurs on approximately 51% of the area. The retrieval method presented is based on an inversion technique and applies a semiempirical backscattering model that describes the dependence of radar backscattering of forest as a function of stem volume, soil permittivity, the extinction coefficient of forest canopy, surface roughness, incidence angle, and radar frequency. It gives an estimate of soil permittivity using active microwave measurements. Applying a Bayesian assimilation scheme, it is also possible to use other soil permittivity retrievals to regulate this estimate to combine for example low resolution passive observations with high resolution active observations for a synergistic retrieval. This way the higher variance in the active retrieval can be constricted with the passive retrieval when at the same time the spatial resolution of the product is improved compared to the passive-only retrieval. The retrieved soil permittivity estimate can be used to detect soil freeze/thaw state by considering the soil to be frozen when the estimate is below a threshold value. The permittivity retrieval can also be used to estimate the relative moisture of the soil. The method was tested using SAR (Synthetic Aperture Radar) measurements from ENVISAT ASAR instrument for the years 2010-2012 and from Sentinel-1 satellite for the years 2015-2016 in Sodankylä area in Northern Finland. The synergistic method was tested combining the SAR measurements with a SMOS (Soil Moisture Ocean Salinity) radiometer based retrieval. The results were validated using in situ measurements from automatic soil state observation stations in Sodankylä calibration and validation (CAL-VAL) site, which is a reference site for several EO (Earth Observation) data products.

Laboratory tests of oviposition by the African malaria mosquito, Anopheles gambiae, on dark soil as influenced by presence or absence of vegetation

PubMed Central

Huang, Juan; Walker, Edward D; Otienoburu, Philip E; Amimo, Fred; Vulule, John; Miller, James R

2006-01-01

Background Physical objects like vegetation can influence oviposition by mosquitoes on soil or water substrates. Anopheles gambiae s. l. is generally thought to utilize puddles over bare soil as its prime larval habitat and to avoid standing water populated with vegetation. In Kisian, Kenya near Kisumu, water often pools in grassy drainage areas both during and after periods of infrequent rains, when typical puddle habitats become scarce because of drying. This raised the question of whether An. gambiae has the behavioural flexibility to switch ovipositional sites when puddles over bare soil are unavailable. Methods To test whether presence and height of grasses influenced oviposition, wild-caught gravid An. gambiae s. l. were offered paired choices between wet, bare soil and wet soil populated with mixed grasses or grasses of differing height. No-choice tests were also conducted by giving females either grassy soil or bare soil. Results In choice tests, females laid four times more eggs on bare, wet soil than soil populated with grasses. However in no-choice tests, egg output was not significantly different whether grasses were present or not. Females laid significantly more eggs on soil populated with short grass than with medium, or tall grass. Conclusion This work shows An. gambiae s. l. has the capacity to oviposit into grassy aquatic habitats when typical puddles over bare soil are unavailable. This knowledge will need to be considered in the design and implementation of programmes aimed at reducing malaria transmission by suppression of An. gambiae s. l. immatures. PMID:17038187

Spatial distribution of soil moisture obtained from gravimetric and TDR methods for SMOS validation, at the Polesie test site SVRT 3275, in Poland

NASA Astrophysics Data System (ADS)

Usowicz, B.; Marczewski, W.; Lipiec, J.; Usowicz, J. B.; Sokolowska, Z.; Dabkowska-Naskret, H.; Hajnos, M.; Lukowski, M. I.

2009-04-01

The purpose is obtaining trustful ground based measurement data of SM (Soil Moisture) for validating SMOS, respectively to spatial and temporal distribution and variations. A use of Time Domain Reflectometric (TDR) method is fast, simple and less destructive, to the soil matter, than a usual standard gravimetric method. TDR tools operate efficiently, enable nearly instant measurements, and allow on collecting many measurements from numerous sites, even when operated manually in short time intervals. The method enables also very frequent sampling of SM at few selected fixed sites, when long terms of temporal variations are needed. In effect one obtains reasonably large data base for determining spatial and temporal distributions of SM. The study is devoted to determining a plan on collecting TDR data, in the scales of small and large field areas, and checking their relevance to those available from gravimetric methods. Finally, the ground based SM distributions are needed for validating other SM distributions, available remotely in larger scales, from the satellite data of ENVISAT-ASAR, and from SMOS (Soil Moisture and Ocean Salinity Mission) when it becomes operational. The ground based evaluations are served mainly by geo-statistical analysis. The space borne estimations are retrieved by image processing and physical models, proper to relevant Remote Sensing (RS) instruments on the orbit. Finally, validation must engage again the geo-statistical evaluations, to assess the agreement between direct and remote sensing means, and provide a measure of trust for extending the limited scales of the ground based data, on concluding the agreement in scales proper to the satellite data. The study is focused mainly on trustful evaluating data from the ground, provided independently on satellite data sources. SM ground based data are collected permanently at 2 selected tests sites, and temporary in areas around the tests sites, in one day sessions, repeated several times per vegetation season. Permanent measurements are provided in profiles, down to 50 cm below surface. Temporary SM measurements are collected by hand held TDR (FOM/mts type, Easy Test Ltd., Lublin, Poland) from the top surface layer (1-6 cm), in a grid covering small and large areas, containing few hundred sites. The same places are served by collecting soil samples for the gravimetric analysis of SM, bulk density, other physical and textural characteristics. Sessions on measurement in large areas on the scale of community are repeated for separate days. The two methods used were compared with correlation coefficient, regression equation and differences of values. The spatial variability of soil moisture from gravimetric and TDR measurements were analyzed using geostatistical methods. The semivariogram parameters were determined and mathematical functions were fitted to empirically derived semivariograms. These functions were used for estimation of spatial distribution of soil moisture in cultivated fields by the kriging method. The results showed that spatial distribution patterns of topsoil soil moisture in the investigated areas obtained from TDR and gravimetric methods were in general similar to each other. The TDR soil moisture contents were dependent on bulk density and texture of soil. In areas with fine-textured soils of lower soil bulk densities (approximately below 1.35 Mg m^-3) we observed that TDR soil moisture and spatial differentiation were greater compared to those with gravimetric method. However at higher bulk densities the inverse was true. The spatial patterns were further modified in areas with domination of coarse-textured soils. Decrease of measurement points results in smoothing soil moisture pattern and at the same time in a greater estimation error. The TDR method can be useful tool for ground moisture measurements and validation of satellite data. The use of specific calibration or correction for soil bulk density and texture with respect to the reflectometric method is recommended. The study is a contribution to the project SWEX (AO-3275) and funded by the Polish Ministry of Science and Higher Education (in part by Grant No. N305 046 31/1707 and in part by Grant No. N305 107 32/3865).

Integrating classical and molecular approaches to evaluate the impact of nanosized zero-valent iron (nZVI) on soil organisms.

PubMed

Saccà, Maria Ludovica; Fajardo, Carmen; Costa, Gonzalo; Lobo, Carmen; Nande, Mar; Martin, Margarita

2014-06-01

Nanosized zero-valent iron (nZVI) is a new option for the remediation of contaminated soil and groundwater, but the effect of nZVI on soil biota is mostly unknown. In this work, nanotoxicological studies were performed in vitro and in two different standard soils to assess the effect of nZVI on autochthonous soil organisms by integrating classical and molecular analysis. Standardised ecotoxicity testing methods using Caenorhabditis elegans were applied in vitro and in soil experiments and changes in microbial biodiversity and biomarker gene expression were used to assess the responses of the microbial community to nZVI. The classical tests conducted in soil ruled out a toxic impact of nZVI on the soil nematode C. elegans in the test soils. The molecular analysis applied to soil microorganisms, however, revealed significant changes in the expression of the proposed biomarkers of exposure. These changes were related not only to the nZVI treatment but also to the soil characteristics, highlighting the importance of considering the soil matrix on a case by case basis. Furthermore, due to the temporal shift between transcriptional responses and the development of the corresponding phenotype, the molecular approach could anticipate adverse effects on environmental biota. Copyright © 2013 Elsevier Ltd. All rights reserved.

Soil Overconsolidation Changes Caused by Dynamic Replacement

NASA Astrophysics Data System (ADS)

Piotr, Kanty; Sławomir, Kwiecień; Jerzy, Sękowski

2017-10-01

In the dynamic replacement method (DR) the soil is improved by initially dropping a large weight (typically 8-20 t) pounder from a significant height up to 25 m. The created crater is filled with a stronger material (gravel, rubble, stone aggregate, debris), and the pounder is dropped once or multiple times again. The construction of dynamic replacement pillars influences the parameters of the adjacent soil. It results from the energy generated by dropping a pounder into the soil. In the current practice, these changes are not taken into the account during the design. This paper focuses on the changes of overconsolidation ratio (OCR) and in situ coefficient of lateral earth pressure (K) values estimated base on cone penetration test (CPTU) and Dilatometric test (DMT) performed at a test site. A single column was constructed and the ground around the column was examined using CPTU and DMT, performed at different distances from the column centre (2, 3, 4 and 6 m) and at different time intervals (during construction and 1, 8, 30 days later). The column was constructed in so-called transition soils (between cohesive and non-cohesive). While interpreting the results of the research, the authors addressed the matter of choosing the procedure of OCR and K indication for transition soils (in this case described as silts and/or sandy silts). Overconsolidation changes may differ depending on the chosen analysis procedure (for cohesive or non-cohesive soils). On the basis of the analysis presented in the paper and the observation of soil (acknowledged as cohesive according to macroscopic observations) during column excavation, it was decided that for more detailed analyses methods dedicated to cohesive soils should be applied. Generally, it can be stated that although the changes were complex, DR pillar formation process resulted in the increase of these parameters. The average increases of OCR and K values were 25% and 10% respectively. The post installation values are not significant from the engineering point of view, but they represent the influence of the formation process of only a single column. The described results indicate that Priebe’s column dimensioning method should be applied with caution, as it assumes the value K=1 which was not obtained in the described research. The results from the conducted tests indicate that different mechanisms occur during stone column formation with vibro-replacement and dynamic replacement. As the authors did not manage to find literature describing the results of K tests in the surrounding of a DR column, the presented results should be acknowledged as significant for designers who will apply the dynamic replacement method.

77 FR 31443 - Energy Conservation Program: Test Procedures for Residential Dishwashers, Dehumidifiers, and...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-25

... dishwashers with a separate soil- sensing cycle, and the normal cycle definition, power supply and detergent... Soiling Requirements 5. Detergent Dosing Specifications E. Incorporation by Reference of an Updated AHAM...: (1) The addition of a method to rate the efficiency of soil-sensing products; (2) the addition of a...

Evaluating Metal Probe Meters for Soil Testing.

ERIC Educational Resources Information Center

Hershey, David R.

1992-01-01

Inexpensive metal probe meters that are sold by garden stores can be evaluated by students for their accuracy in measuring soil pH, moisture, fertility, and salinity. The author concludes that the meters are inaccurate and cannot be calibrated in standard units. However, the student evaluations are useful in learning the methods of soil analysis…

Using Controlled Landslide Initiation Experiments to Test Limit-Equilibrium Analyses of Slope Stability

NASA Astrophysics Data System (ADS)

Reid, M. E.; Iverson, R. M.; Brien, D. L.; Iverson, N. R.; Lahusen, R. G.; Logan, M.

2004-12-01

Most studies of landslide initiation employ limit equilibrium analyses of slope stability. Owing to a lack of detailed data, however, few studies have tested limit-equilibrium predictions against physical measurements of slope failure. We have conducted a series of field-scale, highly controlled landslide initiation experiments at the USGS debris-flow flume in Oregon; these experiments provide exceptional data to test limit equilibrium methods. In each of seven experiments, we attempted to induce failure in a 0.65m thick, 2m wide, 6m3 prism of loamy sand placed behind a retaining wall in the 31° sloping flume. We systematically investigated triggering of sliding by groundwater injection, by prolonged moderate-intensity sprinkling, and by bursts of high intensity sprinkling. We also used vibratory compaction to control soil porosity and thereby investigate differences in failure behavior of dense and loose soils. About 50 sensors were monitored at 20 Hz during the experiments, including nests of tiltmeters buried at 7 cm spacing to define subsurface failure geometry, and nests of tensiometers and pore-pressure sensors to define evolving pore-pressure fields. In addition, we performed ancillary laboratory tests to measure soil porosity, shear strength, hydraulic conductivity, and compressibility. In loose soils (porosity of 0.52 to 0.55), abrupt failure typically occurred along the flume bed after substantial soil deformation. In denser soils (porosity of 0.41 to 0.44), gradual failure occurred within the soil prism. All failure surfaces had a maximum length to depth ratio of about 7. In even denser soil (porosity of 0.39), we could not induce failure by sprinkling. The internal friction angle of the soils varied from 28° to 40° with decreasing porosity. We analyzed stability at failure, given the observed pore-pressure conditions just prior to large movement, using a 1-D infinite-slope method and a more complete 2-D Janbu method. Each method provides a static Factor of Safety (FS), and in theory failure occurs when FS ≤ 1. Using the 1-D analysis, all experiments having failure had FS well below 1 (typically 0.5-0.8). Using the 2-D analysis for these same conditions, FS was less than but closer to 1 (typically 0.8-0.9). For the experiment with no failure, the 2-D FS was, reassuringly, > 1. These results indicate that the 2-D Janbu analysis is more accurate than the 1-D infinite-slope method for computing limit-equilibrium slope stability in shallow slides with limited areal extent.

Development of a nematode offspring counting assay for rapid and simple soil toxicity assessment.

PubMed

Kim, Shin Woong; Moon, Jongmin; Jeong, Seung-Woo; An, Youn-Joo

2018-05-01

Since the introduction of standardized nematode toxicity assays by the American Society for Testing and Materials (ASTM) and International Organization for Standardization (ISO), many studies have reported their use. Given that the currently used standardized nematode toxicity assays have certain limitations, in this study, we examined the use of a novel nematode offspring counting assay for evaluating soil ecotoxicity based on a previous soil-agar isolation method used to recover live adult nematodes. In this new assay, adult Caenorhabditis elegans were exposed to soil using a standardized toxicity assay procedure, and the resulting offspring in test soils attracted by a microbial food source in agar plates were counted. This method differs from previously used assays in terms of its endpoint, namely, the number of nematode offspring. The applicability of the bioassay was demonstrated using metal-spiked soils, which revealed metal concentration-dependent responses, and with 36 field soil samples characterized by different physicochemical properties and containing various metals. Principal component analysis revealed that texture fraction (clay, sand, and silt) and electrical conductivity values were the main factors influencing the nematode offspring counting assay, and these findings warrant further investigation. The nematode offspring counting assay is a rapid and simple process that can provide multi-directional toxicity assessment when used in conjunction with other standard methods. Copyright © 2018 Elsevier Ltd. All rights reserved.

BetaScint{trademark} fiber-optic sensor for detecting strontium-90 and uranium-238 in soil. Innovative technology summary report

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

NONE

1998-12-01

Accurate measurements of radioactivity in soils contaminated with Strontium-90 (Sr-90) or Uranium-238 (U-238) are essential for many DOE site remediation programs. These crucial measurements determine if excavation and soil removal is necessary, where remediation efforts should be focused, and/or if a site has reached closure. Measuring soil contamination by standard EPA laboratory methods typically takes a week (accelerated analytical test turnaround) or a month (standard analytical test turnaround). The time delay extends to operations involving heavy excavation equipment and associated personnel which are the main costs of remediation. This report describes an application of the BetaScint{trademark} fiber-optic sensor that measuresmore » Sr-90 or U-238 contamination in soil samples on site in about 20 minutes, at a much lower cost than time-consuming laboratory methods, to greatly facilitate remediation. This report describes the technology, its performance, its uses, cost, regulatory and policy issues, and lessons learned.« less

Pull-out testing facility for geosynthetics.

DOT National Transportation Integrated Search

1992-11-01

The considerable increase in using geosynthetics in soil reinforcement made it necessary to develop methods of measuring the interaction properties and modeling load transfer in reinforced-soil structures. The large number of factors that influence t...

Soil surface roughness: comparing old and new measuring methods and application in a soil erosion model

NASA Astrophysics Data System (ADS)

Thomsen, L. M.; Baartman, J. E. M.; Barneveld, R. J.; Starkloff, T.; Stolte, J.

2015-04-01

Quantification of soil roughness, i.e. the irregularities of the soil surface due to soil texture, aggregates, rock fragments and land management, is important as it affects surface storage, infiltration, overland flow, and ultimately sediment detachment and erosion. Roughness has been measured in the field using both contact methods (such as roller chain and pinboard) and sensor methods (such as stereophotogrammetry and terrestrial laser scanning (TLS)). A novel depth-sensing technique, originating in the gaming industry, has recently become available for earth sciences: the Xtion Pro method. Roughness data obtained using various methods are assumed to be similar; this assumption is tested in this study by comparing five different methods to measure roughness in the field on 1 m2 agricultural plots with different management (ploughing, harrowing, forest and direct seeding on stubble) in southern Norway. Subsequently, the values were used as input for the LISEM soil erosion model to test their effect on the simulated hydrograph at catchment scale. Results show that statistically significant differences between the methods were obtained only for the fields with direct seeding on stubble; for the other land management types the methods were in agreement. The spatial resolution of the contact methods was much lower than for the sensor methods (10 000 versus at least 57 000 points per square metre). In terms of costs and ease of use in the field, the Xtion Pro method is promising. Results from the LISEM model indicate that especially the roller chain overestimated the random roughness (RR) values and the model subsequently calculated less surface runoff than measured. In conclusion, the choice of measurement method for roughness data matters and depends on the required accuracy, resolution, mobility in the field and available budget. It is recommended to use only one method within one study.

Soil surface roughness: comparing old and new measuring methods and application in a soil erosion model

NASA Astrophysics Data System (ADS)

Thomsen, L. M.; Baartman, J. E. M.; Barneveld, R. J.; Starkloff, T.; Stolte, J.

2014-11-01

Quantification of soil roughness, i.e. the irregularities of the soil surface due to soil texture, aggregates, rock fragments and land management, is important as it affects surface storage, infiltration, overland flow and ultimately sediment detachment and erosion. Roughness has been measured in the field using both contact methods, such as roller chain and pinboard, and sensor methods, such as stereophotogrammetry and terrestrial laser scanning (TLS). A novel depth sensing technique, originating in the gaming industry, has recently become available for earth sciences; the Xtion Pro method. Roughness data obtained using various methods are assumed to be similar; this assumption is tested in this study by comparing five different methods to measure roughness in the field on 1 m2 agricultural plots with different management (ploughing, harrowing, forest and direct seeding on stubble) in southern Norway. Subsequently, the values were used as input for the LISEM soil erosion model to test their effect on the simulated hydrograph on catchment scale. Results show that statistically significant differences between the methods were obtained only for the fields with direct drilling on stubble; for the other land management types the methods were in agreement. The spatial resolution of the contact methods was much lower than for the sensor methods (10 000 versus at least 57 000 points per m2 respectively). In terms of costs and ease of handling in the field, the Xtion Pro method is promising. Results from the LISEM model indicate that especially the roller chain underestimated the RR values and the model thereby calculated less surface runoff than measured. In conclusion: the choice of measurement method for roughness data matters and depends on the required accuracy, resolution, mobility in the field and available budget. It is recommended to use only one method within one study.

A novel in-situ method for real-time monitoring of gas transport in soil

NASA Astrophysics Data System (ADS)

Laemmel, Thomas; Maier, Martin; Schack-Kirchner, Helmer; Lang, Friederike

2017-04-01

Gas exchange between soil and atmosphere is important for the biogeochemistry of soils. Gas transport in soil is commonly assumed to be governed by molecular diffusion and is usually described by the soil gas diffusion coefficient DS characterizing the ability of the soil to "transport passively" gas through the soil. One way to determine DS is sampling soil cores in the field and measuring DS in the lab. Unfortunately this method is destructive and laborious. Moreover, a few previous field studies identified other gas transport processes in soil to significantly enhance the diffusive gas transport. However, until now, no method is available to measure gas transport in situ in the soil. We developed a novel method to monitor gas transport in soil in situ. The method includes a custom made gas sampling device, the continuous injection of an inert tracer gas and inverse gas transport modelling in the soil. The gas sampling device has several sampling depths and can be easily installed into a vertical hole drilled by an auger, which allows for fast installation of the system. Helium (He) as inert tracer gas was injected continuously at the lower end of the device. The resulting steady state distribution of He was used to deduce the depth profile of DS. Gas transport in the soil surrounding the gas-sampling-device/soil system was modeled using the Finite Element Modeling program COMSOL . We tested our new method both in the lab and during two short field studies and compared the results with a reference method using soil cores. DS profiles obtained by our in-situ method were consistent with DS profiles determined based on soil core analyses. During a longer monitoring field campaign, typical soil-moisture effects upon gas diffusivity such as an increase during a drying period or a decrease after rain could be observed consistently. Under windy conditions we additionally measured for the first time the direct enhancement of gas transport in soil due to wind-induced pressure-pumping which could increase the effective DS up to 30% in the topsoil. Our novel monitoring method can be quickly and easily installed and allows for monitoring continuously soil gas transport over a long time. It allows monitoring physical modifications of soil gas diffusivity due to rain events or evaporation but it also allows studying non-diffusive gas transport processes in the soil.

Soil transference patterns on bras: Image processing and laboratory dragging experiments.

PubMed

Murray, Kathleen R; Fitzpatrick, Robert W; Bottrill, Ralph S; Berry, Ron; Kobus, Hilton

2016-01-01

In a recent Australian homicide, trace soil on the victim's clothing suggested she was initially attacked in her front yard and not the park where her body was buried. However the important issue that emerged during the trial was how soil was transferred to her clothing. This became the catalyst for designing a range of soil transference experiments (STEs) to study, recognise and classify soil patterns transferred onto fabric when a body is dragged across a soil surface. Soil deposits of interest in this murder were on the victim's bra and this paper reports the results of anthropogenic soil transfer to bra-cups and straps caused by dragging. Transfer patterns were recorded by digital photography and photomicroscopy. Eight soil transfer patterns on fabric, specific to dragging as the transfer method, appeared consistently throughout the STEs. The distinctive soil patterns were largely dependent on a wide range of soil features that were measured and identified for each soil tested using X-ray Diffraction and Non-Dispersive Infra-Red analysis. Digital photographs of soil transfer patterns on fabric were analysed using image processing software to provide a soil object-oriented classification of all soil objects with a diameter of 2 pixels and above transferred. Although soil transfer patterns were easily identifiable by naked-eye alone, image processing software provided objective numerical data to support this traditional (but subjective) interpretation. Image software soil colour analysis assigned a range of Munsell colours to identify and compare trace soil on fabric to other trace soil evidence from the same location; without requiring a spectrophotometer. Trace soil from the same location was identified by linking soils with similar dominant and sub-dominant Munsell colour peaks. Image processing numerical data on the quantity of soil transferred to fabric, enabled a relationship to be discovered between soil type, clay mineralogy (smectite), particle size and soil moisture content that would not have been possible otherwise. Soil type (e.g. Anthropogenic, gravelly sandy loam soil or Natural, organic-rich soil), clay mineralogy (smectite) and soil moisture content were the greatest influencing factors in all the dragging soil transference tests (both naked eye and measured properties) to explain the eight categories of soil transference patterns recorded. This study was intended to develop a method for dragging soil transference laboratory experiments and create a baseline of preliminary soil type/property knowledge. Results confirm the need to better understand soil behaviour and properties of clothing fabrics by further testing of a wider range of soil types and clay mineral properties. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Aqueous and gaseous nitrogen losses induced by fertilizer application

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

Gu, C.; Maggi, F.; Riley, W.J.

2009-01-15

In recent years concern has grown over the contribution of nitrogen (N) fertilizer use to nitrate (NO{sub 3}{sup -}) water pollution and nitrous oxide (N{sub 2}O), nitric oxide (NO), and ammonia (NH{sub 3}) atmospheric pollution. Characterizing soil N effluxes is essential in developing a strategy to mitigate N leaching and emissions to the atmosphere. In this paper, a previously described and tested mechanistic N cycle model (TOUGHREACT-N) was successfully tested against additional observations of soil pH and N{sub 2}O emissions after fertilization and irrigation, and before plant emergence. We used TOUGHREACT-N to explain the significantly different N gas emissions andmore » nitrate leaching rates resulting from the different N fertilizer types, application methods, and soil properties. The N{sub 2}O emissions from NH{sub 4}{sup +}-N fertilizer were higher than from urea and NO{sub 3}{sup -}-N fertilizers in coarse-textured soils. This difference increased with decreases in fertilization application rate and increases in soil buffering capacity. In contrast to methods used to estimate global terrestrial gas emissions, we found strongly non-linear N{sub 2}O emissions as a function of fertilizer application rate and soil calcite content. Speciation of predicted gas N flux into N{sub 2}O and N{sub 2} depended on pH, fertilizer form, and soil properties. Our results highlighted the need to derive emission and leaching factors that account for fertilizer type, application method, and soil properties.« less

Use of gas push-pull tests for the measurement of methane oxidation in different landfill cover soils.

PubMed

Streese-Kleeberg, Jan; Rachor, Ingke; Gebert, Julia; Stegmann, Rainer

2011-05-01

In order to optimise methane oxidation in landfill cover soils, it is important to be able to accurately quantify the amount of methane oxidised. This research considers the gas push-pull test (GPPT) as a possible method to quantify oxidation rates in situ. During a GPPT, a gas mixture consisting of one or more reactive gases (e.g., CH(4), O(2)) and one or more conservative tracers (e.g., argon), is injected into the soil. Following this, the mixture of injected gas and soil air is extracted from the same location and periodically sampled. The kinetic parameters for the biological oxidation taking place in the soil can be derived from the differences in the breakthrough curves. The original method of Urmann et al. (2005) was optimised for application in landfill cover soils and modified to reduce the analytical effort required. Optimised parameters included the flow rate during the injection phase and the duration of the experiment. 50 GPPTs have been conducted at different landfills in Germany during different seasons. Generally, methane oxidation rates ranged between 0 and 150 g m(soil air)(-3)h(-1). At one location, rates up to 440 g m(soil air)(-3)h(-1) were measured under particularly favourable conditions. The method is simple in operation and does not require expensive equipment besides standard laboratory gas chromatographs. Copyright © 2010 Elsevier Ltd. All rights reserved.

GICHD Mine Dog Testing Project - Soil Sample Results No.3

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

PHELAN, JAMES M.; BARNETT, JAMES L.; BENDER, SUSAN FAE ANN

2003-03-01

A mine dog evaluation project initiated by the Geneva International Center for Humanitarian Demining is evaluating the capability and reliability of mine detection dogs. The performance of field-operational mine detection dogs will be measured in test minefields in Afghanistan and Bosnia containing actual, but unfused landmines. Repeated performance testing over two years through various seasonal weather conditions will provide data simulating near real world conditions. Soil samples will be obtained adjacent to the buried targets repeatedly over the course of the test. Chemical analysis results from these soil samples will be used to evaluate correlations between mine dog detection performancemore » and seasonal weather conditions. This report documents the analytical chemical methods and results from the third batch of soils received. This batch contained samples from Kharga, Afghanistan collected in October 2002.« less

GICHD mine dog testing project : soil sample results #5.

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

Barnett, James L.; Phelan, James M.; Archuleta, Luisa M.

2004-01-01

A mine dog evaluation project initiated by the Geneva International Center for Humanitarian Demining is evaluating the capability and reliability of mine detection dogs. The performance of field-operational mine detection dogs will be measured in test minefields in Afghanistan containing actual, but unfused landmines. Repeated performance testing over two years through various seasonal weather conditions will provide data simulating near real world conditions. Soil samples will be obtained adjacent to the buried targets repeatedly over the course of the test. Chemical analysis results from these soil samples will be used to evaluate correlations between mine dog detection performance and seasonalmore » weather conditions. This report documents the analytical chemical methods and results from the fifth batch of soils received. This batch contained samples from Kharga, Afghanistan collected in June 2003.« less

Soil separator and sampler and method of sampling

DOEpatents

O'Brien, Barry H [Idaho Falls, ID; Ritter, Paul D [Idaho Falls, ID

2010-02-16

A soil sampler includes a fluidized bed for receiving a soil sample. The fluidized bed may be in communication with a vacuum for drawing air through the fluidized bed and suspending particulate matter of the soil sample in the air. In a method of sampling, the air may be drawn across a filter, separating the particulate matter. Optionally, a baffle or a cyclone may be included within the fluidized bed for disentrainment, or dedusting, so only the finest particulate matter, including asbestos, will be trapped on the filter. The filter may be removable, and may be tested to determine the content of asbestos and other hazardous particulate matter in the soil sample.

Ensemble learning for spatial interpolation of soil potassium content based on environmental information.

PubMed

Liu, Wei; Du, Peijun; Wang, Dongchen

2015-01-01

One important method to obtain the continuous surfaces of soil properties from point samples is spatial interpolation. In this paper, we propose a method that combines ensemble learning with ancillary environmental information for improved interpolation of soil properties (hereafter, EL-SP). First, we calculated the trend value for soil potassium contents at the Qinghai Lake region in China based on measured values. Then, based on soil types, geology types, land use types, and slope data, the remaining residual was simulated with the ensemble learning model. Next, the EL-SP method was applied to interpolate soil potassium contents at the study site. To evaluate the utility of the EL-SP method, we compared its performance with other interpolation methods including universal kriging, inverse distance weighting, ordinary kriging, and ordinary kriging combined geographic information. Results show that EL-SP had a lower mean absolute error and root mean square error than the data produced by the other models tested in this paper. Notably, the EL-SP maps can describe more locally detailed information and more accurate spatial patterns for soil potassium content than the other methods because of the combined use of different types of environmental information; these maps are capable of showing abrupt boundary information for soil potassium content. Furthermore, the EL-SP method not only reduces prediction errors, but it also compliments other environmental information, which makes the spatial interpolation of soil potassium content more reasonable and useful.

Effects of ivermectin application on the diversity and function of dung and soil fauna: Regulatory and scientific background information.

PubMed

Adler, Nicole; Bachmann, Jean; Blanckenhorn, Wolf U; Floate, Kevin D; Jensen, John; Römbke, Jörg

2016-08-01

The application of veterinary medical products to livestock can impact soil organisms in manure-amended fields or adversely affect organisms that colonize dung pats of treated animals and potentially retard the degradation of dung on pastures. For this reason, the authorization process for veterinary medicinal products in the European Union includes a requirement for higher-tier tests when adverse effects on dung organisms are observed in single-species toxicity tests. However, no guidance documents for the performance of higher-tier tests are available. Hence, an international research project was undertaken to develop and validate a proposed test method under varying field conditions of climate, soil, and endemic coprophilous fauna at Lethbridge (Canada), Montpellier (France), Zurich (Switzerland), and Wageningen (The Netherlands). The specific objectives were to determine if fecal residues of an anthelmintic with known insecticidal activity (ivermectin) showed similar effects across sites on 1) insects breeding in dung of treated animals, 2) coprophilous organisms in the soil beneath the dung, and 3) rates of dung degradation. By evaluating the effects of parasiticides on communities of dung-breeding insects and soil fauna under field conditions, the test method meets the requirements of a higher-tier test as mandated by the European Union. The present study provides contextual information on authorization requirements for veterinary medicinal products and on the structure and function of dung and soil organism communities. It also provides a summary of the main findings. Subsequent studies on this issue provide detailed information on different aspects of this overall project. Environ Toxicol Chem 2016;35:1914-1923. © 2015 SETAC. © 2015 SETAC.

Optimization of viral resuspension methods for carbon-rich soils along a permafrost thaw gradient

DOE PAGES

Trubl, Gareth; Solonenko, Natalie; Chittick, Lauren; ...

2016-05-17

Permafrost stores approximately 50% of global soil carbon (C) in a frozen form; it is thawing rapidly under climate change, and little is known about viral communities in these soils or their roles in C cycling. In permafrost soils, microorganisms contribute significantly to C cycling, and characterizing them has recently been shown to improve prediction of ecosystem function. In other ecosystems, viruses have broad ecosystem and community impacts ranging from host cell mortality and organic matter cycling to horizontal gene transfer and reprogramming of core microbial metabolisms. Here we developed an optimized protocol to extract viruses from three types ofmore » high organic-matter peatland soils across a permafrost thaw gradient (palsa, moss-dominated bog, and sedge-dominated fen). Three separate experiments were used to evaluate the impact of chemical buffers, physical dispersion, storage conditions, and concentration and purification methods on viral yields. The most successful protocol, amended potassium citrate buffer with bead-beating or vortexing and BSA, yielded on average as much as 2-fold more virus-like particles (VLPs) g –1of soil than other methods tested. All method combinations yielded VLPs g –1of soil on the 10 8order of magnitude across all three soil types. The different storage and concentration methods did not yield significantly more VLPs g –1of soil among the soil types. In conclusion, this research provides much-needed guidelines for resuspending viruses from soils, specifically carbon-rich soils, paving the way for incorporating viruses into soil ecology studies.« less

Optimization of viral resuspension methods for carbon-rich soils along a permafrost thaw gradient

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

Trubl, Gareth; Solonenko, Natalie; Chittick, Lauren

Permafrost stores approximately 50% of global soil carbon (C) in a frozen form; it is thawing rapidly under climate change, and little is known about viral communities in these soils or their roles in C cycling. In permafrost soils, microorganisms contribute significantly to C cycling, and characterizing them has recently been shown to improve prediction of ecosystem function. In other ecosystems, viruses have broad ecosystem and community impacts ranging from host cell mortality and organic matter cycling to horizontal gene transfer and reprogramming of core microbial metabolisms. Here we developed an optimized protocol to extract viruses from three types ofmore » high organic-matter peatland soils across a permafrost thaw gradient (palsa, moss-dominated bog, and sedge-dominated fen). Three separate experiments were used to evaluate the impact of chemical buffers, physical dispersion, storage conditions, and concentration and purification methods on viral yields. The most successful protocol, amended potassium citrate buffer with bead-beating or vortexing and BSA, yielded on average as much as 2-fold more virus-like particles (VLPs) g –1of soil than other methods tested. All method combinations yielded VLPs g –1of soil on the 10 8order of magnitude across all three soil types. The different storage and concentration methods did not yield significantly more VLPs g –1of soil among the soil types. In conclusion, this research provides much-needed guidelines for resuspending viruses from soils, specifically carbon-rich soils, paving the way for incorporating viruses into soil ecology studies.« less

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

NASA Astrophysics Data System (ADS)

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

2017-04-01

Simple infiltration experiments carried out in the field allow an easy and inexpensive way of characterizing soil hydraulic behavior, maintaining the functional connection of the sampled soil volume with the surrounding soil. The beerkan method consists of a three-dimensional (3D) infiltration experiment at zero pressure head (Haverkamp et al., 1996). It uses a simple annular ring inserted to a depth of about 0.01 m to avoid lateral loss of the ponded water. Soil disturbance is minimized by the limited ring insertion depth. Infiltration time of small volumes of water repeatedly poured on the confined soil are measured to determine the cumulative infiltration. Different algorithms based on this methodology (the so-called BEST family of algorithms) were developed for the determination of soil hydraulic characteristic parameters (Bagarello et al., 2014a; Lassabatere et al., 2006; Yilmaz et al., 2010). Recently, Bagarello et al. (2014b) developed a Simplified method based on a Beerkan Infiltration run (SBI method) to determine saturated soil hydraulic conductivity, Ks, by only the transient phase of a beerkan infiltration run and an estimate of the α* parameter, expressing the relative importance of gravity and capillary forces during an infiltration process (Reynolds and Elrick, 1990). However, several problems yet arise with the existing BEST-algorithms and the SBI method, including (i) the need of supplementary field and laboratory measurements (Bagarello et al., 2013); (ii) the difficulty to detect a linear relationship between I / √t and √t in the early stage of the infiltration process (Bagarello et al., 2014b); (iii) estimation of negative Ks values for hydrophobic soils (Di Prima et al., 2016). In this investigation, a new Simplified method based on the analysis of the Steady-state Beerkan Infiltration run (SSBI method) was proposed and tested. In particular, analytical data were generated to simulate beerkan infiltration experiments for six contrasting 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 < 3.7%). Therefore, this last method performed better than the other tested methods in most cases. The analysis of the field data supported the usability of the SSBI method in different environments and conditions to obtain an acceptable prediction of Ks, i.e. similar to the one that can be obtained with the BEST-steady algorithm (Bagarello et al., 2014a). Finally, this investigation yielded encouraging signs on the applicability of the SSBI method for a trustworthy estimation of Ks by the near steady-state phase of a beerkan infiltration run. REFERENCES Bagarello, V., Castellini, M., Di Prima, S., Giordano, G., Iovino, M., 2013. Testing a Simplified Approach to Determine Field Saturated Soil Hydraulic Conductivity. Procedia Environmental Sciences 19, 599-608. doi:10.1016/j.proenv.2013.06.068 Bagarello, V., Di Prima, S., Iovino, M., 2014a. Comparing Alternative Algorithms to Analyze the Beerkan Infiltration Experiment. Soil Science Society of America Journal 78, 724. doi:10.2136/sssaj2013.06.0231 Bagarello, V., Di Prima, S., Iovino, M., Provenzano, G., 2014b. Estimating field-saturated soil hydraulic conductivity by a simplified Beerkan infiltration experiment. Hydrological Processes 28, 1095-1103. doi:10.1002/hyp.9649 Di Prima, S., Lassabatere, L., Bagarello, V., Iovino, M., Angulo-Jaramillo, R., 2016. Testing a new automated single ring infiltrometer for Beerkan infiltration experiments. Geoderma 262, 20-34. doi:10.1016/j.geoderma.2015.08.006 Haverkamp, R., Arrúe, J., Vandervaere, J., Braud, I., Boulet, G., Laurent, J., 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

Preparation of a Frozen Regolith Simulant Bed for ISRU Component Testing in a Vacuum Chamber

NASA Technical Reports Server (NTRS)

Klenhenz, Julie; Linne, Diane

2013-01-01

In-Situ Resource Utilization (ISRU) systems and components have undergone extensive laboratory and field tests to expose hardware to relevant soil environments. The next step is to combine these soil environments with relevant pressure and temperature conditions. Previous testing has demonstrated how to incorporate large bins of unconsolidated lunar regolith into sufficiently sized vacuum chambers. In order to create appropriate depth dependent soil characteristics that are needed to test drilling operations for the lunar surface, the regolith simulant bed must by properly compacted and frozen. While small cryogenic simulant beds have been created for laboratory tests, this scale effort will allow testing of a full 1m drill which has been developed for a potential lunar prospector mission. Compacted bulk densities were measured at various moisture contents for GRC-3 and Chenobi regolith simulants. Vibrational compaction methods were compared with the previously used hammer compaction, or "Proctor", method. All testing was done per ASTM standard methods. A full 6.13 m3 simulant bed with 6 percent moisture by weight was prepared, compacted in layers, and frozen in a commercial freezer. Temperature and desiccation data was collected to determine logistics for preparation and transport of the simulant bed for thermal vacuum testing. Once in the vacuum facility, the simulant bed will be cryogenically frozen with liquid nitrogen. These cryogenic vacuum tests are underway, but results will not be included in this manuscript.

EVALUATION OF IMMUNOASSAY METHODS FOR DETERMINATION OF 3,5,6-TRICHLORO-2-PYRIDINOL IN MULTIPLE SAMPLE MEDIA

EPA Science Inventory

Two enzyme-linked immunosorbent assay (ELISA) methods were evaluated for the determination of 3,5,6-trichloro-2-pyridinol (3,5,6-TCP) in multiple sample media (dust, soil, food, and urine). The dust and soil samples were analyzed by the RaPID (TM) commercial immunoassay testing ...

Comparison of sprinkler droplet size and velocity measurements using a laser precipitation meter and photographic method

USDA-ARS?s Scientific Manuscript database

Kinetic energy of water droplets has a substantial effect on development of a soil surface seal and infiltration rate of bare soil. Methods for measuring sprinkler droplet size and velocity needed to calculate droplet kinetic energy have been developed and tested over the past 50 years, each with ad...

An Evaluation Method for the Suppression of Pathogenic Fusarium oxysporum by Soil Microorganisms Using the Dilution Plate Technique.

PubMed

Mitsuboshi, Masahiro; Kioka, Yuuzou; Noguchi, Katsunori; Asakawa, Susumu

2016-09-29

Soil-borne diseases caused by pathogenic microorganisms are one of the main factors responsible for the decline in crop yields in farmlands. Pathogenic Fusarium oxysporum causes serious damage to various crops, and, thus, a feasible diagnostic method for soil-borne diseases is required. We herein examined a simple method to evaluate the suppressiveness of soil microorganisms against a pathogen by co-cultivating indigenous soil microorganisms and a pathogenic fungus (F. oxysporum f. sp. spinaciae). We inoculated F. oxysporum onto the center of agar medium plates mixed with a dilution series of a suspension of organic fertilizers or soil. After an approximately one-week cultivation, the growth degree of F. oxysporum was estimated based on the size of the colonies that formed on the plates. The growth degree of F. oxysporum significantly differed among the organic fertilizers tested, indicating the usefulness of the method for evaluating suppressiveness by organic fertilizers. Differences in the growth degrees of F. oxysporum were associated with the incidence of disease in spinach on soil treated with organic fertilizers and inoculated with a pathogenic F. oxysporum strain. These results suggested that this method provides some useful information on the suppressiveness of organic fertilizers and soil against Fusarium wilt.

An Evaluation Method for the Suppression of Pathogenic Fusarium oxysporum by Soil Microorganisms Using the Dilution Plate Technique

PubMed Central

Mitsuboshi, Masahiro; Kioka, Yuuzou; Noguchi, Katsunori; Asakawa, Susumu

2016-01-01

Soil-borne diseases caused by pathogenic microorganisms are one of the main factors responsible for the decline in crop yields in farmlands. Pathogenic Fusarium oxysporum causes serious damage to various crops, and, thus, a feasible diagnostic method for soil-borne diseases is required. We herein examined a simple method to evaluate the suppressiveness of soil microorganisms against a pathogen by co-cultivating indigenous soil microorganisms and a pathogenic fungus (F. oxysporum f. sp. spinaciae). We inoculated F. oxysporum onto the center of agar medium plates mixed with a dilution series of a suspension of organic fertilizers or soil. After an approximately one-week cultivation, the growth degree of F. oxysporum was estimated based on the size of the colonies that formed on the plates. The growth degree of F. oxysporum significantly differed among the organic fertilizers tested, indicating the usefulness of the method for evaluating suppressiveness by organic fertilizers. Differences in the growth degrees of F. oxysporum were associated with the incidence of disease in spinach on soil treated with organic fertilizers and inoculated with a pathogenic F. oxysporum strain. These results suggested that this method provides some useful information on the suppressiveness of organic fertilizers and soil against Fusarium wilt. PMID:27558588

Control of embankment settlement field verification on PCPT prediction methods.

DOT National Transportation Integrated Search

2011-07-01

Piezocone penetration tests (PCPT) have been widely used by geotechnical engineers for subsurface investigation and evaluation of different soil properties such as strength and deformation characteristics of the soil. This report focuses on the verif...

Control of embankment settlement field verification on PCPT prediction methods.

DOT National Transportation Integrated Search

2011-07-01

Piezocone penetration tests (PCPT) have been widely used by geotechnical engineers for subsurface : investigation and evaluation of different soil properties such as strength and deformation characteristics of the : soil. This report focuses on the v...

The Analysis of Soil Resistance During Screw Displacement Pile Installation

NASA Astrophysics Data System (ADS)

Krasinski, Adam

2015-02-01

The application of screw displacement piles (SDP) is still increasing due to their high efficiency and many advantages. However, one technological problem is a serious disadvantage of those piles. It relates to the generation of very high soil resistance during screw auger penetration, especially when piles are installed in non-cohesive soils. In many situations this problem causes difficulties in creating piles of designed length and diameter. It is necessary to find a proper method for prediction of soil resistance during screw pile installation. The analysis of screw resistances based on model and field tests is presented in the paper. The investigations were carried out as part of research project, financed by the Polish Ministry of Science and Higher Education. As a result of tests and analyses the empirical method for prediction of rotation resistance (torque) during screw auger penetration in non-cohesive subsoil based on CPT is proposed.

Effects of Low-Temperature Plasma-Sterilization on Mars Analog Soil Samples Mixed with Deinococcus radiodurans.

PubMed

Schirmack, Janosch; Fiebrandt, Marcel; Stapelmann, Katharina; Schulze-Makuch, Dirk

2016-05-26

We used Ar plasma-sterilization at a temperature below 80 °C to examine its effects on the viability of microorganisms when intermixed with tested soil. Due to a relatively low temperature, this method is not thought to affect the properties of a soil, particularly its organic component, to a significant degree. The method has previously been shown to work well on spacecraft parts. The selected microorganism for this test was Deinococcus radiodurans R1, which is known for its remarkable resistance to radiation effects. Our results showed a reduction in microbial counts after applying a low temperature plasma, but not to a degree suitable for a sterilization of the soil. Even an increase of the treatment duration from 1.5 to 45 min did not achieve satisfying results, but only resulted in in a mean cell reduction rate of 75% compared to the untreated control samples.

In situ silicone tube microextraction: a new method for undisturbed sampling of root-exuded thiophenes from marigold (Tagetes erecta L.) in soil.

PubMed

Mohney, Brian K; Matz, Tricia; Lamoreaux, Jessica; Wilcox, David S; Gimsing, Anne Louise; Mayer, Philipp; Weidenhamer, Jeffrey D

2009-11-01

The difficulties of monitoring allelochemical concentrations in soil and their dynamics over time have been a major barrier to testing hypotheses of allelopathic effects. Here, we evaluate three diffusive sampling strategies that employ polydimethylsiloxane (PDMS) sorbents to map the spatial distribution and temporal dynamics of root-exuded thiophenes from the African marigold, Tagetes erecta. Solid phase root zone extraction (SPRE) probes constructed by inserting stainless steel wire into PDMS tubing were used to monitor thiophene concentrations at various depths beneath marigolds growing in PVC pipes. PDMS sheets were used to map the distribution of thiophenes beneath marigolds grown in thin glass boxes. Concentrations of the two major marigold thiophenes measured by these two methods were extremely variable in both space and time. Dissection and analysis of roots indicated that distribution of thiophenes in marigold roots also was quite variable. A third approach used 1 m lengths of PDMS microtubing placed in marigold soil for repeated sampling of soil without disturbance of the roots. The two ends of the tubing remained out of the soil so that solvent could be washed through the tubing to collect samples for HPLC analysis. Unlike the other two methods, initial experiments with this approach show more uniformity of response, and suggest that soil concentrations of marigold thiophenes are affected greatly even by minimal disturbance of the soil. Silicone tube microextraction gave a linear response for alpha-terthienyl when maintained in soils spiked with 0-10 ppm of this thiophene. This method, which is experimentally simple and uses inexpensive materials, should be broadly applicable to the measurement of non-polar root exudates, and thus provides a means to test hypotheses about the role of root exudates in plant-plant and other interactions.

BIOACCESSIBILITY TESTS ACCURATELY ESTIMATE ...

EPA Pesticide Factsheets

Hazards of soil-borne Pb to wild birds may be more accurately quantified if the bioavailability of that Pb is known. To better understand the bioavailability of Pb to birds, we measured blood Pb concentrations in Japanese quail (Coturnix japonica) fed diets containing Pb-contaminated soils. Relative bioavailabilities were expressed by comparison with blood Pb concentrations in quail fed a Pb acetate reference diet. Diets containing soil from five Pb-contaminated Superfund sites had relative bioavailabilities from 33%-63%, with a mean of about 50%. Treatment of two of the soils with P significantly reduced the bioavailability of Pb. The bioaccessibility of the Pb in the test soils was then measured in six in vitro tests and regressed on bioavailability. They were: the “Relative Bioavailability Leaching Procedure” (RBALP) at pH 1.5, the same test conducted at pH 2.5, the “Ohio State University In vitro Gastrointestinal” method (OSU IVG), the “Urban Soil Bioaccessible Lead Test”, the modified “Physiologically Based Extraction Test” and the “Waterfowl Physiologically Based Extraction Test.” All regressions had positive slopes. Based on criteria of slope and coefficient of determination, the RBALP pH 2.5 and OSU IVG tests performed very well. Speciation by X-ray absorption spectroscopy demonstrated that, on average, most of the Pb in the sampled soils was sorbed to minerals (30%), bound to organic matter 24%, or present as Pb sulfate 18%. Ad

Remediation of grey forest soils heavily polluted with heavy metals by means of their leaching at acidic pH followed by the soil reclamation by means of neutralization and bacterial manure addition

NASA Astrophysics Data System (ADS)

Georgiev, Plamen; Groudev, Stoyan; Spasova, Irena; Nicolova, Marina

2014-05-01

Some grey forest soils in Western Bulgaria are heavily polluted with heavy metals (copper, lead, and zinc), arsenic, and uranium due to the infiltration of acid mine drainage generated at the abandoned uranium mine Curilo. This paper presents some results from a study about soil remediation based on the contaminants leaching from the topsoil by means of irrigation with solutions containing sulphuric acid or its in situ generation by means of sulphur-oxidizing chemolithotrophic bacteria in or without the presence of finely cut straw. These methods were tested in large scale zero suction lysimeters. The approaches based on S° and finely cut straw addition was the most efficient amongst the tested methods and for seven months of soil remediation the concentration of all soil contaminants were decreased below the relevant Maximum Admissible Concentration (MAC). Neutralization of the soil acidity was applied as a next stage of soil reclamation by adding CaCO3 and cow manure. As a result, soil pH increased from strongly acidic (2.36) to slightly acidic (6.15) which allowed subsequent addition of humic acids and bacterial manure to the topsoil. The soil habitat changed in this way facilitated the growth of microorganisms which restored the biogeochemical cycles of nitrogen and carbon to the levels typical for non-polluted grey forest soil.

Analysis of beryllium and depleted uranium: An overview of detection methods in aerosols and soils

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

Camins, I.; Shinn, J.H.

We conducted a survey of commercially available methods for analysis of beryllium and depleted uranium in aerosols and soils to find a reliable, cost-effective, and sufficiently precise method for researchers involved in environmental testing at the Yuma Proving Ground, Yuma, Arizona. Criteria used for evaluation include cost, method of analysis, specificity, sensitivity, reproducibility, applicability, and commercial availability. We found that atomic absorption spectrometry with graphite furnace meets these criteria for testing samples for beryllium. We found that this method can also be used to test samples for depleted uranium. However, atomic absorption with graphite furnace is not as sensitive amore » measurement method for depleted uranium as it is for beryllium, so we recommend that quality control of depleted uranium analysis be maintained by testing 10 of every 1000 samples by neutron activation analysis. We also evaluated 45 companies and institutions that provide analyses of beryllium and depleted uranium. 5 refs., 1 tab.« less

An Establishment of Rainfall-induced Soil Erosion Index for the Slope Land in Watershed

NASA Astrophysics Data System (ADS)

Tsai, Kuang-Jung; Chen, Yie-Ruey; Hsieh, Shun-Chieh; Shu, Chia-Chun; Chen, Ying-Hui

2014-05-01

With more and more concentrated extreme rainfall events as a result of climate change, in Taiwan, mass cover soil erosion occurred frequently and led to sediment related disasters in high intensity precipiton region during typhoons or torrential rain storms. These disasters cause a severely lost to the property, public construction and even the casualty of the resident in the affected areas. Therefore, we collected soil losses by using field investigation data from the upstream of watershed where near speific rivers to explore the soil erosion caused by heavy rainfall under different natural environment. Soil losses induced by rainfall and runoff were obtained from the long-term soil depth measurement of erosion plots, which were established in the field, used to estimate the total volume of soil erosion. Furthermore, the soil erosion index was obtained by referring to natural environment of erosion test plots and the Universal Soil Loss Equation (USLE). All data collected from field were used to compare with the one obtained from laboratory test recommended by the Technical Regulation for Soil and Water Conservation in Taiwan. With MATLAB as a modeling platform, evaluation model for soil erodibility factors was obtained by golden section search method, considering factors contributing to the soil erosion; such as degree of slope, soil texture, slope aspect, the distance far away from water system, topography elevation, and normalized difference vegetation index (NDVI). The distribution map of soil erosion index was developed by this project and used to estimate the rainfall-induced soil losses from erosion plots have been established in the study area since 2008. All results indicated that soil erodibility increases with accumulated rainfall amount regardless of soil characteristics measured in the field. Under the same accumulated rainfall amount, the volume of soil erosion also increases with the degree of slope and soil permeability, but decreases with the shear strength of top soil within 30 cm and the coverage of vegetation. The slope plays more important role than the soil permeability on soil erosion. However, soil losses are not proportional to the hardness of top soil or subsurface soil. The empirical formula integrated with soil erosion index map for evaluating soil erodibility obtained from optimal numerical search method can be used to estimate the soil losses induced by rainfall and runoff erosion on slope land in Taiwan. Keywords: Erosion Test Plot, Soil Erosion, Optimal Numerical Search, Universal Soil Loss Equation.

Evaluation of Three Field-Based Methods for Quantifying Soil Carbon

PubMed Central

Izaurralde, Roberto C.; Rice, Charles W.; Wielopolski, Lucian; Ebinger, Michael H.; Reeves, James B.; Thomson, Allison M.; Francis, Barry; Mitra, Sudeep; Rappaport, Aaron G.; Etchevers, Jorge D.; Sayre, Kenneth D.; Govaerts, Bram; McCarty, Gregory W.

2013-01-01

Three advanced technologies to measure soil carbon (C) density (g C m−2) are deployed in the field and the results compared against those obtained by the dry combustion (DC) method. The advanced methods are: a) Laser Induced Breakdown Spectroscopy (LIBS), b) Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFTS), and c) Inelastic Neutron Scattering (INS). The measurements and soil samples were acquired at Beltsville, MD, USA and at Centro International para el Mejoramiento del Maíz y el Trigo (CIMMYT) at El Batán, Mexico. At Beltsville, soil samples were extracted at three depth intervals (0–5, 5–15, and 15–30 cm) and processed for analysis in the field with the LIBS and DRIFTS instruments. The INS instrument determined soil C density to a depth of 30 cm via scanning and stationary measurements. Subsequently, soil core samples were analyzed in the laboratory for soil bulk density (kg m−3), C concentration (g kg−1) by DC, and results reported as soil C density (kg m−2). Results from each technique were derived independently and contributed to a blind test against results from the reference (DC) method. A similar procedure was employed at CIMMYT in Mexico employing but only with the LIBS and DRIFTS instruments. Following conversion to common units, we found that the LIBS, DRIFTS, and INS results can be compared directly with those obtained by the DC method. The first two methods and the standard DC require soil sampling and need soil bulk density information to convert soil C concentrations to soil C densities while the INS method does not require soil sampling. We conclude that, in comparison with the DC method, the three instruments (a) showed acceptable performances although further work is needed to improve calibration techniques and (b) demonstrated their portability and their capacity to perform under field conditions. PMID:23383225

Avoidance behaviour of Eisenia fetida to carbofuran, chlorpyrifos, mancozeb and metamidophos in natural soils from the highlands of Colombia.

PubMed

García-Santos, Glenda; Keller-Forrer, Karin

2011-07-01

Earthworm avoidance behaviour test is an important screening tool in soil eco-toxicology. This test has been developed and validated under North American and European conditions. However, little research has been performed on the avoidance test in the tropics. This work demonstrates the potential suitability of the avoidance behaviour test as screening method in the highlands of Colombia using Eisenia fetida as the bio-indicator species on contaminated soils with carbofuran and chlorpyrifos. Though for the two active ingredients 100% avoidance was not reached, a curve with six meaningful concentrations is provided. No significant avoidance behaviour trend was found for mancozeb and methamidophos. Tests were conducted in the field yielded similar results to the tests carried out in the laboratory for chlorpyrifos and mancozeb. However, for the case of carbofuran and methamidophos, differences of more than double in avoidance were obtained. Divergence might be explained by soil and temperature conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Microbial rRNA: rDNA gene ratios may be unexpectedly low due to extracellular DNA preservation in soils

USDA-ARS?s Scientific Manuscript database

We tested a method of estimating the activity of detectable individual bacterial and archaeal OTUs within a community by calculating ratios of absolute 16S rRNA to rDNA copy numbers. We investigated phylogenetically coherent patterns of activity among soil prokaryotes in non-growing soil communitie...

Assessment of metal(loid)s phytoavailability in intensive agricultural soils by the application of single extractions to rhizosphere soil.

PubMed

Pinto, Edgar; Almeida, Agostinho A; Ferreira, Isabel M P L V O

2015-03-01

The influence of soil properties on the phytoavailability of metal(loid)s in a soil-plant system was evaluated. The content of extractable metal(loid)s obtained by using different extraction methods was also compared. To perform this study, a test plant (Lactuca sativa) and rhizosphere soil were sampled at 5 different time points (2, 4, 6, 8 and 10 weeks of plant growth). Four extraction methods (Mehlich 3, DTPA, NH4NO3 and CaCl2) were used. Significant positive correlations between the soil extractable content and lettuce shoot content were obtained for several metal(loid)s. The extraction with NH4NO3 showed the higher number of strong positive correlations indicating the suitability of this method to estimate metal(loid)s phytoavailability. The soil CEC, OM, pH, texture and oxides content significantly influenced the distribution of metal(loid)s between the phytoavailable and non-phytoavailable fractions. A reliable prediction model for Cr, V, Ni, As, Pb, Co, Cd, and Sb phytoavailability was obtained considering the amount of metal(loid) extracted by the NH4NO3 method and the main soil properties. This work shows that the analysis of rhizosphere soil by single extractions methods is a reliable approach to estimate metal(loid)s phytoavailability. Copyright © 2014 Elsevier Inc. All rights reserved.

Experimental Study on Vacuum Dynamic Consolidation Treatment of Soft Soil Foundation

NASA Astrophysics Data System (ADS)

Fu-lai, Ni; Xin, Wen; Xiao-bin, Zhang; Wei, Li

2017-11-01

In view of the deficiency of the saturated silt clay foundation reinforced by the dynamic consolidation method, combination the project of soft foundation treatment test area in Tangshan, the reaserch analysed indexes, included groundwater level, pore water pressure, settlement about soil layer and so on, by use of field tests and indoor geotechnical tests, The results showed that the whole reinforcement effect with vacuum dynamic compaction method to blow fill foundation is obvious, due to the result of vacuum precipitation, generally, the excess pore water pressure can be dissipated by 90% above in 2 days around and the effective compaction coefficient can reached more than 0.9,the research work in soft foundation treatment engineering provide a new method and thought to similar engineering.

Experimental Study on Fatigue Performance of Foamed Lightweight Soil

NASA Astrophysics Data System (ADS)

Qiu, Youqiang; Yang, Ping; Li, Yongliang; Zhang, Liujun

2017-12-01

In order to study fatigue performance of foamed lightweight soil and forecast its fatigue life in the supporting project, on the base of preliminary tests, beam fatigue tests on foamed lightweight soil is conducted by using UTM-100 test system. Based on Weibull distribution and lognormal distribution, using the mathematical statistics method, fatigue equations of foamed lightweight soil are obtained. At the same time, according to the traffic load on real road surface of the supporting project, fatigue life of formed lightweight soil is analyzed and compared with the cumulative equivalent axle loads during the design period of the pavement. The results show that even the fatigue life of foamed lightweight soil has discrete property, the linear relationship between logarithmic fatigue life and stress ratio still performs well. Especially, the fatigue life of Weibull distribution is more close to that derived from the lognormal distribution, in the instance of 50% guarantee ratio. In addition, the results demonstrated that foamed lightweight soil as subgrade filler has good anti-fatigue performance, which can be further adopted by other projects in the similar research domain.

Predicting the spatial distribution of soil profile in Adapazari/Turkey by artificial neural networks using CPT data

NASA Astrophysics Data System (ADS)

Arel, Ersin

2012-06-01

The infamous soils of Adapazari, Turkey, that failed extensively during the 46-s long magnitude 7.4 earthquake in 1999 have since been the subject of a research program. Boreholes, piezocone soundings and voluminous laboratory testing have enabled researchers to apply sophisticated methods to determine the soil profiles in the city using the existing database. This paper describes the use of the artificial neural network (ANN) model to predict the complex soil profiles of Adapazari, based on cone penetration test (CPT) results. More than 3236 field CPT readings have been collected from 117 soundings spread over an area of 26 km2. An attempt has been made to develop the ANN model using multilayer perceptrons trained with a feed-forward back-propagation algorithm. The results show that the ANN model is fairly accurate in predicting complex soil profiles. Soil identification using CPT test results has principally been based on the Robertson charts. Applying neural network systems using the chart offers a powerful and rapid route to reliable prediction of the soil profiles.

Lung bioaccessibility of contaminants in particulate matter of geological origin.

PubMed

Guney, Mert; Chapuis, Robert P; Zagury, Gerald J

2016-12-01

Human exposure to particulate matter (PM) has been associated with adverse health effects. While inhalation exposure to airborne PM is a prominent research subject, exposure to PM of geological origin (i.e., generated from soil/soil-like material) has received less attention. This review discusses the contaminants in PM of geological origin and their relevance for human exposure and then evaluates lung bioaccessibility assessment methods and their use. PM of geological origin can contain toxic elements as well as organic contaminants. Observed/predicted PM lung clearance times are long, which may lead to prolonged contact with lung environment. Thus, certain exposure scenarios warrant the use of in vitro bioaccessibility testing to predict lung bioavailability. Limited research is available on lung bioaccessibility test development and test application to PM of geological origin. For in vitro tests, test parameter variation between different studies and concerns about physiological relevance indicate a crucial need for test method standardization and comparison with relevant animal data. Research is recommended on (1) developing robust in vitro lung bioaccessibility methods, (2) assessing bioaccessibility of various contaminants (especially polycyclic aromatic hydrocarbons (PAHs)) in PM of diverse origin (surface soils, mine tailings, etc.), and (3) risk characterization to determine relative importance of exposure to PM of geological origin.

Rapid determination of soil quality and earthworm impacts on soil microbial communities using fluorescence-based respirometry

NASA Astrophysics Data System (ADS)

Prendergast-Miller, Miranda T.; Thurston, Josh; Taylor, Joe; Helgason, Thorunn; Ashauer, Roman; Hodson, Mark E.

2017-04-01

We applied a fluorescence-based respirometry method currently devised for aquatic ecotoxicology studies to rapidly measure soil microbial oxygen consumption as a function of soil quality. In this study, soil was collected from an arable wheat field and the field margin. These two soil habitats are known to differ in their soil quality due to differences in their use and management as well as plant, microbial and earthworm community. The earthworm Lumbricus terrestris was incubated in arable or margin soil for three weeks. After this initial phase, a transfer experiment was then conducted to test the hypothesis that earthworm 'migration' alters soil microbial community function and diversity. In this transfer experiment, earthworms incubated in margin soil were transferred to arable soil. The converse transfer (i.e. earthworms incubated in arable soil) was also conducted. Soils of each type with no earthworms were also incubated as controls. After a further four week incubation, the impact of earthworm migration on the soil microbial community was tested by measuring oxygen consumption. Replicated soil slurry subsamples were aliquoted into individual respirometer wells (600 μl volume) on a glass 24-well microplate (Loligo Systems, Denmark) fitted with non-invasive, reusable oxygen sensor spots. The sealed microplate was then attached to an oxygen fluorescence sensor (SDR SensorDish Reader, PreSens, Germany). Oxygen consumption was measured in real-time over a 2 hr period following standard operating procedures. Soil microbial activity was measured with and without an added carbon source (glucose or cellulose, 50 mg C L-1). Using this system, we were able to differentiate between soil type, earthworm treatment and C source. Earthworm-driven impacts on soil microbial oxygen consumption were also supported by changes in soil microbial community structure and diversity revealed using DNA-based sequencing techniques. This method provides a simple and rapid system for measuring soil quality and has the potential for use in a variety of scenarios investigating impacts on soil microbial function.

Approximating Phosphorus Leaching from Agricultural Organic Soils by Soil Testing.

PubMed

Zheng, Z M; Zhang, T Q; Kessel, C; Tan, C S; O'Halloran, I P; Wang, Y T; Speranzini, D; Van Eerd, L L

2015-11-01

Phosphorus applied to soils in excess of crop requirement could create situations favorable to P enrichment in subsurface flow that contributes to eutrophication of surface water. This pathway of P loss can be more severe in muck (i.e., organic) soils where agricultural production is intensive. This study evaluated the suitability of various environmental and agronomic soil P tests initially designed for mineral soils to predict dissolved reactive P (DRP) in subsurface flow from organic soils. Intact soil columns were collected from 44 muck soils in Ontario to provide a wide range of soil test P levels. A lysimeter leaching study was conducted by evenly adding water in an amount equivalent to 5 mm of rainfall. The leachate DRP concentration was linearly related to soil water-extractable P and CaCl-extractable P with values of 0.90 and 0.93, respectively, and to Bray-1 P and FeO-impregnated filter paper extractable P in a split-line model with a change point. Mehlich-3 P and Olsen P, a method recommended for agronomic P calibration in Ontario, were not related to leachate DRP concentration. All P sorption index (PSI) based degree of P saturation (DPS) values were closely related to leachate DRP in split-line models, with the DPS indices expressed as Bray-1 P/PSI and FeO-P/PSI having the highest correlation with leachate DRP concentration. Because it is desirable from practical and economic standpoints that the environmental risk assessment shares the same soil test with agronomic P calibration, the two PSI-based DPS indices as presented can be considered as environmental risk indicators of DRP subsurface loss from organic soils. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

GICHD mine dog testing project - soil sample results #4.

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

Barnett, James L.; Phelan, James M.; Archuleta, Luisa M.

2003-08-01

A mine dog evaluation project initiated by the Geneva International Center for Humanitarian Demining is evaluating the capability and reliability of mine detection dogs. The performance of field-operational mine detection dogs will be measured in test minefields in Afghanistan and Bosnia containing actual, but unfused landmines. Repeated performance testing over two years through various seasonal weather conditions will provide data simulating near real world conditions. Soil samples will be obtained adjacent to the buried targets repeatedly over the course of the test. Chemical analysis results from these soil samples will be used to evaluate correlations between mine dog detection performancemore » and seasonal weather conditions. This report documents the analytical chemical methods and results from the fourth batch of soils received. This batch contained samples from Kharga, Afghanistan collected in April 2003 and Sarajevo, Bosnia collected in May 2003.« less

Validity and extension of the SCS-CN method for computing infiltration and rainfall-excess rates

NASA Astrophysics Data System (ADS)

Mishra, Surendra Kumar; Singh, Vijay P.

2004-12-01

A criterion is developed for determining the validity of the Soil Conservation Service curve number (SCS-CN) method. According to this criterion, the existing SCS-CN method is found to be applicable when the potential maximum retention, S, is less than or equal to twice the total rainfall amount. The criterion is tested using published data of two watersheds. Separating the steady infiltration from capillary infiltration, the method is extended for predicting infiltration and rainfall-excess rates. The extended SCS-CN method is tested using 55 sets of laboratory infiltration data on soils varying from Plainfield sand to Yolo light clay, and the computed and observed infiltration and rainfall-excess rates are found to be in good agreement.

Estimating soil matric potential in Owens Valley, California

USGS Publications Warehouse

Sorenson, Stephen K.; Miller, R.F.; Welch, M.R.; Groeneveld, D.P.; Branson, F.A.

1988-01-01

Much of the floor of the Owens Valley, California, is covered with alkaline scrub and alkaline meadow plant communities, whose existence is dependent partly on precipitation and partly on water infiltrated into the rooting zone from the shallow water table. The extent to which these plant communities are capable of adapting to and surviving fluctuations in the water table depends on physiological adaptations of the plants and on the water content, matric potential characteristics of the soils. Two methods were used to estimate soil matric potential in test sites in Owens Valley. The first was the filter-paper method, which uses water content of filter papers equilibrated to water content of soil samples taken with a hand auger. The other method of estimating soil matric potential was a modeling approach based on data from this and previous investigations. These data indicate that the base 10 logarithm of soil matric potential is a linear function of gravimetric soil water content for a particular soil. Estimates of soil water characteristic curves were made at two sites by averaging the gravimetric soil water content and soil matric potential values from multiple samples at 0.1 m depths derived by using the hand auger and filter paper method and entering these values in the soil water model. The characteristic curves then were used to estimate soil matric potential from estimates of volumetric soil water content derived from neutron-probe readings. Evaluation of the modeling technique at two study sites indicated that estimates of soil matric potential within 0.5 pF units of the soil matric potential value derived by using the filter paper method could be obtained 90 to 95% of the time in soils where water content was less than field capacity. The greatest errors occurred at depths where there was a distinct transition between soils of different textures. (Lantz-PTT)

Visual soil evaluation - future research requirements

NASA Astrophysics Data System (ADS)

Emmet-Booth, Jeremy; Forristal, Dermot; Fenton, Owen; Ball, Bruce; Holden, Nick

2017-04-01

A review of Visual Soil Evaluation (VSE) techniques (Emmet-Booth et al., 2016) highlighted their established utility for soil quality assessment, though some limitations were identified; (1) The examination of aggregate size, visible intra-porosity and shape forms a key assessment criterion in almost all methods, thus limiting evaluation to structural form. The addition of criteria that holistically examine structure may be desirable. For example, structural stability can be indicated using dispersion tests or examining soil surface crusting, while the assessment of soil colour may indirectly indicate soil organic matter content, a contributor to stability. Organic matter assessment may also indicate structural resilience, along with rooting, earthworm numbers or shrinkage cracking. (2) Soil texture may influence results or impeded method deployment. Modification of procedures to account for extreme texture variation is desirable. For example, evidence of compaction in sandy or single grain soils greatly differs to that in clayey soils. Some procedures incorporate separate classification systems or adjust deployment based on texture. (3) Research into impacts of soil moisture content on VSE evaluation criteria is required. Criteria such as rupture resistance and shape may be affected by moisture content. It is generally recommended that methods are deployed on moist soils and quantification of influences of moisture variation on results is necessary. (4) Robust sampling strategies for method deployment are required. Dealing with spatial variation differs between methods, but where methods can be deployed over large areas, clear instruction on sampling is required. Additionally, as emphasis has been placed on the agricultural production of soil, so the ability of VSE for exploring structural quality in terms of carbon storage, water purification and biodiversity support also requires research. References Emmet-Booth, J.P., Forristal. P.D., Fenton, O., Ball, B.C. & Holden, N.M. 2016. A review of visual soil evaluation techniques for soil structure. Soil Use and Management, 32, 623-634.

Behavior of nonplastic silty soils under cyclic loading.

PubMed

Ural, Nazile; Gunduz, Zeki

2014-01-01

The engineering behavior of nonplastic silts is more difficult to characterize than is the behavior of clay or sand. Especially, behavior of silty soils is important in view of the seismicity of several regions of alluvial deposits in the world, such as the United States, China, and Turkey. In several hazards substantial ground deformation, reduced bearing capacity, and liquefaction of silty soils have been attributed to excess pore pressure generation during dynamic loading. In this paper, an experimental study of the pore water pressure generation of silty soils was conducted by cyclic triaxial tests on samples of reconstituted soils by the slurry deposition method. In all tests silty samples which have different clay percentages were studied under different cyclic stress ratios. The results have showed that in soils having clay content equal to and less than 10%, the excess pore pressure ratio buildup was quicker with an increase in different cyclic stress ratios. When fine and clay content increases, excess pore water pressure decreases constant cyclic stress ratio in nonplastic silty soils. In addition, the applicability of the used criteria for the assessment of liquefaction susceptibility of fine grained soils is examined using laboratory test results.

Behavior of Nonplastic Silty Soils under Cyclic Loading

PubMed Central

Ural, Nazile; Gunduz, Zeki

2014-01-01

The engineering behavior of nonplastic silts is more difficult to characterize than is the behavior of clay or sand. Especially, behavior of silty soils is important in view of the seismicity of several regions of alluvial deposits in the world, such as the United States, China, and Turkey. In several hazards substantial ground deformation, reduced bearing capacity, and liquefaction of silty soils have been attributed to excess pore pressure generation during dynamic loading. In this paper, an experimental study of the pore water pressure generation of silty soils was conducted by cyclic triaxial tests on samples of reconstituted soils by the slurry deposition method. In all tests silty samples which have different clay percentages were studied under different cyclic stress ratios. The results have showed that in soils having clay content equal to and less than 10%, the excess pore pressure ratio buildup was quicker with an increase in different cyclic stress ratios. When fine and clay content increases, excess pore water pressure decreases constant cyclic stress ratio in nonplastic silty soils. In addition, the applicability of the used criteria for the assessment of liquefaction susceptibility of fine grained soils is examined using laboratory test results. PMID:24672343

Phytotoxicity of trace metals in spiked and field-contaminated soils: Linking soil-extractable metals with toxicity.

PubMed

Hamels, Fanny; Malevé, Jasmina; Sonnet, Philippe; Kleja, Dan Berggren; Smolders, Erik

2014-11-01

Soil tests have been widely developed to predict trace metal uptake by plants. The prediction of metal toxicity, however, has rarely been tested. The present study was set up to compare 8 established soil tests for diagnosing phytotoxicity in contaminated soils. Nine soils contaminated with Zn or Cu by metal mining, smelting, or processing were collected. Uncontaminated reference soils with similar soil properties were sampled, and series of increasing contamination were created by mixing each with the corresponding soil. In addition, each reference soil was spiked with either ZnCl2 or CuCl2 at several concentrations. Total metal toxicity to barley seedling growth in the field-contaminated soils was up to 30 times lower than that in corresponding spiked soils. Total metal (aqua regia-soluble) toxicity thresholds of 50% effective concentrations (EC50) varied by factors up to 260 (Zn) or 6 (Cu) among soils. For Zn, variations in EC50 thresholds decreased as aqua regia > 0.43 M HNO3  > 0.05 M ethylenediamine tetraacetic acid (EDTA) > 1 M NH4 NO3  > cobaltihexamine > diffusive gradients in thin films (DGT) > 0.001 M CaCl2 , suggesting that the last extraction is the most robust phytotoxicity index for Zn. The EDTA extraction was the most robust for Cu-contaminated soils. The isotopically exchangeable fraction of the total soil metal in the field-contaminated soils markedly explained the lower toxicity compared with spiked soils. The isotope exchange method can be used to translate soil metal limits derived from soils spiked with metal salts to site-specific soil metal limits. © 2014 SETAC.

Soil classification based on cone penetration test (CPT) data in Western Central Java

NASA Astrophysics Data System (ADS)

Apriyono, Arwan; Yanto, Santoso, Purwanto Bekti; Sumiyanto

2018-03-01

This study presents a modified friction ratio range for soil classification i.e. gravel, sand, silt & clay and peat, using CPT data in Western Central Java. The CPT data was obtained solely from Soil Mechanic Laboratory of Jenderal Soedirman University that covers more than 300 sites within the study area. About 197 data were produced from data filtering process. IDW method was employed to interpolated friction ratio values in a regular grid point for soil classification map generation. Soil classification map was generated and presented using QGIS software. In addition, soil classification map with respect to modified friction ratio range was validated using 10% of total measurements. The result shows that silt and clay dominate soil type in the study area, which is in agreement with two popular methods namely Begemann and Vos. However, the modified friction ratio range produces 85% similarity with laboratory measurements whereby Begemann and Vos method yields 70% similarity. In addition, modified friction ratio range can effectively distinguish fine and coarse grains, thus useful for soil classification and subsequently for landslide analysis. Therefore, modified friction ratio range proposed in this study can be used to identify soil type for mountainous tropical region.

Evaluation on expansive performance of the expansive soil using electrical responses

NASA Astrophysics Data System (ADS)

Chu, Ya; Liu, Songyu; Bate, Bate; Xu, Lei

2018-01-01

Light structures, such as highways and railroads, built on expansive soils are prone to damages from the swelling of their underlain soil layers. Considerable amount of research has been conducted to characterize the swelling properties of expansive soils. Current swell characterization models, however, are limited by lack of standardized tests. Electrical methods are non-destructive, and are faster and less expensive than the traditional geotechnical methods. Therefore, geo-electrical methods are attractive for defining soil characteristics, including the swelling behavior. In this study, comprehensive laboratory experiments were undertaken to measure the free swelling and electrical resistivity of the mixtures of commercial kaolinite and bentonite. The electrical conductivity of kaolinite-bentonite mixtures was measured by a self-developed four-electrode soil resistivity box. Increasing the free swelling rate of the kaolinite-bentonite mixtures (0.72 to 1 of porosity of soils samples) led to a reduction in the electrical resistivity and an increase in conductivity. A unique relationship between free swelling rate and normalized surface conductivity was constructed for expensive soils by eliminating influences of porosity and m exponent. Therefore, electrical response measurement can be used to characterize the free swelling rate of expensive soils.

COMPARISON OF IMMUNOASSAY AND GAS CHROMATOGRAPHY/MASS SPECTROMETRY METHODS FOR MEASURING 3,5,6-TRICHLORO-2PYRIDINOL IN MULTIPLE SAMPLE MEDIA

EPA Science Inventory

Two enzyme-linked immunosorbent assay (ELISA) methods were evaluated for the determination of 3,5,6-trichloro-2-pyridinol (3,5,6-TCP) in multiple sample media (dust, soil, food, and urine). The dust and soil samples were analyzed by a commercial RaPID immunoassay testing kit. ...

Enhancing a Remote-Sensing Method for Soil Moisture by Accounting for Regional Soil, Vegetation, and Climatic Characteristics

NASA Astrophysics Data System (ADS)

Sahaar, A. S.; Niemann, J. D.

2016-12-01

Accurate knowledge of root-zone soil moisture is critical for understanding the perpetuation of droughts and managing agricultural water systems. A remote-sensing method based on optical and thermal satellite imagery has been previously proposed to estimate fine-resolution (30 m) root-zone soil moisture over large regions. This method uses Landsat imagery to calculate all the components of the surface energy balance and then calculates the evaporative fraction (Λ) as the ratio of the latent heat flux to the sum of the sensible and latent heat fluxes. Root-zone soil moisture (θ) is then estimated from an empirical relationship with Λ. A similar approach has also been proposed to estimate the degree of saturation. Previous testing of this method for a semiarid region of southeastern Colorado has shown that a single relationship between θ and Λ does not apply universally. The primary objective of this study is to evaluate the impact of regional soil, vegetation, and climatic conditions on the form and strength of the Λ- θ relationship. To accomplish this goal, a global sensitivity analysis is performed using the Extended Fourier Amplitude Sensitivity Test (FAST) and a physically-based model (Hydrus-1D) that simulates both the land-surface energy balance and soil moisture dynamics. The modeling results show that, within a given climatic region, soil characteristics are very important in determining the shape of the Λ-θ relationship, while vegetation characteristics have the largest effect on the strength of the relationship. The modeling results also indicate that the annual average rainfall, which helps determine the climatic region, has a strong effect on both the form and strength of the relationship. From this analysis, the constants that define the Λ-θ relationships are estimated using regional characteristics. This approach allows the remote-sensing method to be adapted to local conditions and has the potential to greatly improve its performance.

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

NASA Astrophysics Data System (ADS)

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

2014-05-01

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

Modification to the AOAC Sporicidal Activity of Disinfectants Test (Method 966.04): collaborative study.

PubMed

Tomasino, Stephen F; Hamilton, Martin A

2006-01-01

In an effort to improve AOAC Method 966.04, the Sporicidal Activity of Disinfectants Test, selected modifications to the procedure were evaluated in a collaborative study. Method 966.04 is used to generate efficacy data to support the product registration of sporicides and sterilants. The method is a carrier-based test that provides a qualitative measure of product efficacy against spores of Bacillus subtilis and Clostridium sporogenes. The use of garden soil extract and the lack of standard procedures for the enumeration of spores and neutralization of the test chemicals have been considered problematic for many years. The proposed modifications were limited to the B. subtilis and hard surface carrier (porcelain penicylinder) components of the method. The study included the evaluation of a replacement for soil extract nutrient broth and an establishment of a minimum spore titer per carrier, both considered crucial for the improvement and utilization of the method. Additionally, an alternative hard surface material and a neutralization confirmation procedure were evaluated. To determine the equivalence of the proposed alternatives to the standard method, 3 medium/carrier combinations, (1) soil extract nutrient broth/porcelain carrier (current method), (2) nutrient agar amended with 5 microg/mL manganese sulfate/porcelain carrier, and (3) nutrient agar amended with 5 microg/mL manganese sulfate/stainless steel carrier were analyzed for carrier counts, HCI resistance, efficacy, quantitative efficacy, and spore wash-off. The test chemicals used in the study represent 3 chemical classes and are commercially available antimicrobial liquid products: sodium hypochlorite (bleach), glutaraldehyde, and a combination of peracetic acid and hydrogen peroxide. Four laboratories participated in the study. The results of the spore titer per carrier, HCI resistance, efficacy, and wash-off studies demonstrate that amended nutrient agar in conjunction with the porcelain is comparable to the current method, soil extract nutrient broth/porcelain. The nutrient agar method is simple, inexpensive, reproducible, and provides an ample supply of high quality spores. Due to the current use of porcelain carriers for testing C. sporogenes, it is advisable to retain the use of porcelain carriers until stainless steel can be evaluated as a replacement carrier material for Clostridium. The evaluation of stainless steel for Clostridium has been initiated by the Study Director. Study Director recommendations for First Action revisions are provided in a modified method.

Resilient moduli of typical Missouri soils and unbound granular base materials.

DOT National Transportation Integrated Search

2009-01-01

The objective of this project was to determine the resilient moduli for common Missouri subgrade soils and typical unbound granular base materials in accordance with the AASHTO T 307 test method. The results allow Missouri Department of Transportatio...

Feasibility of electrokinetic oxygen supply for soil bioremediation purposes.

PubMed

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

2014-12-01

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

Geostatistical interpolation of available copper in orchard soil as influenced by planting duration.

PubMed

Fu, Chuancheng; Zhang, Haibo; Tu, Chen; Li, Lianzhen; Luo, Yongming

2018-01-01

Mapping the spatial distribution of available copper (A-Cu) in orchard soils is important in agriculture and environmental management. However, data on the distribution of A-Cu in orchard soils is usually highly variable and severely skewed due to the continuous input of fungicides. In this study, ordinary kriging combined with planting duration (OK_PD) is proposed as a method for improving the interpolation of soil A-Cu. Four normal distribution transformation methods, namely, the Box-Cox, Johnson, rank order, and normal score methods, were utilized prior to interpolation. A total of 317 soil samples were collected in the orchards of the Northeast Jiaodong Peninsula. Moreover, 1472 orchards were investigated to obtain a map of planting duration using Voronoi tessellations. The soil A-Cu content ranged from 0.09 to 106.05 with a mean of 18.10 mg kg -1 , reflecting the high availability of Cu in the soils. Soil A-Cu concentrations exhibited a moderate spatial dependency and increased significantly with increasing planting duration. All the normal transformation methods successfully decreased the skewness and kurtosis of the soil A-Cu and the associated residuals, and also computed more robust variograms. OK_PD could generate better spatial prediction accuracy than ordinary kriging (OK) for all transformation methods tested, and it also provided a more detailed map of soil A-Cu. Normal score transformation produced satisfactory accuracy and showed an advantage in ameliorating smoothing effect derived from the interpolation methods. Thus, normal score transformation prior to kriging combined with planting duration (NSOK_PD) is recommended for the interpolation of soil A-Cu in this area.

A dynamic soil chamber system coupled with a tunable diode laser for online measurements of delta-13C, delta-18O, and efflux rate of soil respired CO2

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

Powers, Heath H; Mcdowell, Nate; Hanson, David

2009-01-01

High frequency observations of the stable isotopic composition of CO(2) effluxes from soil have been sparse due in part to measurement challenges. We have developed an open-system method that utilizes a flow-through chamber coupled to a tunable diode laser (TDL) to quantify the rate of soil CO(2) efflux and its delta(13)C and delta(18)O values (delta(13)C(R) and delta(18)O(R), respectively). We tested the method first in the laboratory using an artificial soil test column and then in a semi-arid woodland. We found that the CO(2) efflux rates of 1.2 to 7.3 micromol m(-2) s(-1) measured by the chamber-TDL system were similar tomore » measurements made using the chamber and an infrared gas analyzer (IRGA) (R(2) = 0.99) and compared well with efflux rates generated from the soil test column (R(2) = 0.94). Measured delta(13)C and delta(18)O values of CO(2) efflux using the chamber-TDL system at 2 min intervals were not significantly different from source air values across all efflux rates after accounting for diffusive enrichment. Field measurements during drought demonstrated a strong dependency of CO(2) efflux and isotopic composition on soil water content. Addition of water to the soil beneath the chamber resulted in average changes of +6.9 micromol m(-2) s(-1), -5.0 per thousand, and -55.0 per thousand for soil CO(2) efflux, delta(13)C(R) and delta(18)O(R), respectively. All three variables initiated responses within 2 min of water addition, with peak responses observed within 10 min for isotopes and 20 min for efflux. The observed delta(18)O(R) was more enriched than predicted from temperature-dependent H(2)O-CO(2) equilibration theory, similar to other recent observations of delta(18)O(R) from dry soils (Wingate L, Seibt U, Maseyk K, Ogee J, Almeida P, Yakir D, Pereira JS, Mencuccini M. Global Change Biol. 2008; 14: 2178). The soil chamber coupled with the TDL was found to be an effective method for capturing soil CO(2) efflux and its stable isotope composition at high temporal frequency.« less

Review and evaluation of the effects of xenobiotic chemicals on microorganisms in soil. [139 references

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

Hicks, R.J.; Van Voris, P.

1988-02-01

The primary objective was to review and evaluate the relevance and quality of existing xenobiotic data bases and test methods for evaluating direct and indirect effects (both adverse and beneficial) of xenobiotics on the soil microbial community; direct and indirect effects of the soil microbial community on xenobiotics; and adequacy of test methods used to evaluate these effects and interactions. Xenobiotic chemicals are defined here as those compounds, both organic and inorganic, produced by man and introduced into the environment at concentrations that cause undesirable effects. Because soil serves as the main repository for many of these chemicals, it thereforemore » has a major role in determining their ultimate fate. Once released, the distribution of xenobiotics between environmental compartments depends on the chemodynamic properties of the compounds, the physicochemical properties of the soils, and the transfer between soil-water and soil-air interfaces and across biological membranes. Abiotic and biotic processes can transform the chemical compound, thus altering its chemical state and, subsequently, its toxicity and reactivity. Ideally, the conversion is to carbon dioxide, water, and mineral elements, or at least, to some harmless substance. However, intermediate transformation products, which can become toxic pollutants in their own right, can sometimes be formed. 139 refs., 6 figs., 11 tabs.« less

An enzyme-linked immunosorbent assay for the determination of dioxins in contaminated sediment and soil samples

PubMed Central

Van Emon, Jeanette M.; Chuang, Jane C.; Lordo, Robert A.; Schrock, Mary E.; Nichkova, Mikaela; Gee, Shirley J.; Hammock, Bruce D.

2010-01-01

A 96-microwell enzyme-linked immunosorbent assay (ELISA) method was evaluated to determine PCDDs/PCDFs in sediment and soil samples from an EPA Superfund site. Samples were prepared and analyzed by both the ELISA and a gas chromatography/high resolution mass spectrometry (GC/HRMS) method. Comparable method precision, accuracy, and detection level (8 ng kg−1) were achieved by the ELISA method with respect to GC/HRMS. However, the extraction and cleanup method developed for the ELISA requires refinement for the soil type that yielded a waxy residue after sample processing. Four types of statistical analyses (Pearson correlation coefficient, paired t-test, nonparametric tests, and McNemar’s test of association) were performed to determine whether the two methods produced statistically different results. The log-transformed ELISA-derived 2,3,7,8-tetrachlorodibenzo-p-dioxin values and logtransformed GC/HRMS-derived TEQ values were significantly correlated (r = 0.79) at the 0.05 level. The median difference in values between ELISA and GC/HRMS was not significant at the 0.05 level. Low false negative and false positive rates (<10%) were observed for the ELISA when compared to the GC/HRMS at 1000 ng TEQ kg−1. The findings suggest that immunochemical technology could be a complementary monitoring tool for determining concentrations at the 1000 ng TEQ kg−1 action level for contaminated sediment and soil. The ELISA could also be used in an analytical triage approach to screen and rank samples prior to instrumental analysis. PMID:18313102

Piezocone Penetration Testing Device

DOT National Transportation Integrated Search

2017-01-03

Hydraulic characteristics of soils can be estimated from piezocone penetration test (called PCPT hereinafter) by performing dissipation test or on-the-fly using advanced analytical techniques. This research report presents a method for fast estimatio...

A comparison of soil moisture sensors for space flight applications

NASA Technical Reports Server (NTRS)

Norikane, J. H.; Prenger, J. J.; Rouzan-Wheeldon, D. T.; Levine, H. G.

2005-01-01

Plants will be an important part of future long-term space missions. Automated plant growth systems require accurate and reliable methods of monitoring soil moisture levels. There are a number of different methods to accomplish this task. This study evaluated sensors using the capacitance method (ECH2O), the heat-pulse method (TMAS), and tensiometers, compared to soil water loss measured gravimetrically in a side-by-side test. The experiment monitored evaporative losses from substrate compartments filled with 1- to 2-mm baked calcinated clay media. The ECH2O data correlated well with the gravimetric measurements, but over a limited range of soil moisture. The averaged TMAS sensor data overstated soil moisture content levels. The tensiometer data appeared to track evaporative losses in the 0.5- to 2.5-kPa range of matric potential that corresponds to the water content needed to grow plants. This small range is characteristic of large particle media, and thus high-resolution tensiometers are required to distinguish changing moisture contents in this range.

Comparison of specific-yield estimates for calculating evapotranspiration from diurnal groundwater-level fluctuations

NASA Astrophysics Data System (ADS)

Gribovszki, Zoltán

2018-05-01

Methods that use diurnal groundwater-level fluctuations are commonly used for shallow water-table environments to estimate evapotranspiration (ET) and recharge. The key element needed to obtain reliable estimates is the specific yield (Sy), a soil-water storage parameter that depends on unsaturated soil-moisture and water-table fluxes, among others. Soil-moisture profile measurement down to the water table, along with water-table-depth measurements, can provide a good opportunity to calculate Sy values even on a sub-daily scale. These values were compared with Sy estimates derived by traditional techniques, and it was found that slug-test-based Sy values gave the most similar results in a sandy soil environment. Therefore, slug-test methods, which are relatively cheap and require little time, were most suited to estimate Sy using diurnal fluctuations. The reason for this is that the timeframe of the slug-test measurement is very similar to the dynamic of the diurnal signal. The dynamic characteristic of Sy was also analyzed on a sub-daily scale (depending mostly on the speed of drainage from the soil profile) and a remarkable difference was found in Sy with respect to the rate of change of the water table. When comparing constant and sub-daily (dynamic) Sy values for ET estimation, the sub-daily Sy application yielded higher correlation, but only a slightly smaller deviation from the control ET method, compared with the usage of constant Sy.

[Effects of rare earth elements on soil fauna community structure and their ecotoxicity to Holotrichia parallela].

PubMed

Li, Guiting; Jiang, Junqi; Chen, Jie; Zou, Yunding; Zhang, Xincai

2006-01-01

By the method of OECD filter paper contact, this paper studied the effects of applied rare earth elements on soil fauna community structure and their ecological toxicity to Holotrichia parallela in bean field. The results showed that there were no significant differences between the treatments and the control in soil fauna species, quantity of main species, and diversity index. Urgent and chronic toxic test showed that the differences between the treatments and the control were not significant. It was suggested that within the range of test dosages, rare earth elements had little ecological toxicity to Holotrichia parallela, and did not change the soil fauna community structure.

Effect of Lime Stabilization on Vertical Deformation of Laterite Halmahera Soil

NASA Astrophysics Data System (ADS)

Saing, Zubair; Djainal, Herry

2018-04-01

In this paper, the study was conducted to determine the lime effect on vertical deformation of road base physical model of laterite Halmahera soil. The samples of laterite soil were obtained from Halmahera Island, North Maluku Province, Indonesia. Soil characteristics were obtained from laboratory testing, according to American Standard for Testing and Materials (ASTM), consists of physical, mechanical, minerals, and chemical. The base layer of physical model testing with the dimension; 2m of length, 2m of width, and 1.5m of height. The addition of lime with variations of 3, 5, 7, an 10%, based on maximum dry density of standard Proctor test results and cured for 28 days. The model of lime treated laterite Halmahera soil with 0,1m thickness placed on subgrade layer with 1,5m thickness. Furthermore, the physical model was given static vertical loading. Some dial gauge is placed on the lime treated soil surface with distance interval 20cm, to read the vertical deformation that occurs during loading. The experimentals data was analyzed and validated with numerical analysis using finite element method. The results showed that the vertical deformation reduced significantly on 10% lime content (three times less than untreated soil), and qualify for maximum deflection (standard requirement L/240) on 7-10% lime content.

High-throughput diagnosis of potato cyst nematodes in soil samples.

PubMed

Reid, Alex; Evans, Fiona; Mulholland, Vincent; Cole, Yvonne; Pickup, Jon

2015-01-01

Potato cyst nematode (PCN) is a damaging soilborne pest of potatoes which can cause major crop losses. In 2010, a new European Union directive (2007/33/EC) on the control of PCN came into force. Under the new directive, seed potatoes can only be planted on land which has been found to be free from PCN infestation following an official soil test. A major consequence of the new directive was the introduction of a new harmonized soil sampling rate resulting in a threefold increase in the number of samples requiring testing. To manage this increase with the same staffing resources, we have replaced the traditional diagnostic methods. A system has been developed for the processing of soil samples, extraction of DNA from float material, and detection of PCN by high-throughput real-time PCR. Approximately 17,000 samples are analyzed each year using this method. This chapter describes the high-throughput processes for the production of float material from soil samples, DNA extraction from the entire float, and subsequent detection and identification of PCN within these samples.

The wettability of selected organic soils in Poland

NASA Astrophysics Data System (ADS)

Całka, A.; Hajnos, M.

2009-04-01

The wettability was measured in the laboratory by means of two methods: Water Drop Penetration Time (WDPT) test and Thin Column Wicking (TCW) method. WDPT is fast and simple method and was used to investigate potential water repellency of analyzed samples. TCW is an indirect method and was used to determine contact angles and surface free energy components. The measurement was performed in horizontal teflon chambers for thin-layer chromatography, adapted for tubes 10 cm long. The experiment was carried out on muck soils (samples were taken from two levels of soil profile: 0-20 cm and 20-40 cm) and peat soils. There were two types of peats: low-moor peats and high moor peats. Samples of low-moor peats were taken from level 25-75 cm (alder peat) and 75-125cm (sedge peat) and 25-75 cm (peloid peat). Samples of high moor peats from level 25-175 cm (sphagnum peat) and 175-225 cm (sphagnum peat with Eriophorum). There was found no variability in persistence of potential water repellency but there were differences in values of contact angles of individual soil samples. Both muck and peat samples are extremely water repellent soils. Water droplets persisted on the surface of soils for more than 24 hours. Contact angles and surface free energy components for all samples were differentiated. Ranges of water contact angles for organic soils are from 27,54o to 96,50o. The highest values of contact angles were for sphagnum peats, and the lowest for muck soil from 20-40 cm level. It means, that there are differences in wettability between these samples. Muck soil is the best wettable and sphagnum peats is the worst wettable soil. If the content of organic compounds in the soil exceeds 40% (like in peats), the tested material displays only dispersion-type interactions. Therefore for peat soils, the technique of thin column wicking could only be used to determine the dispersive component γiLW. For muck soils it was also determined electron-acceptor (Lewis acid) γ+ and electron-donor (Lewis base) γ- surface free energy components. The authors gratefully acknowledge the Ministry of Science and Higher Education for financial support of this work (grant No. N N310 149335).

Biodegradation of poly(hydroxy butanoic acid) copolymer mulch films in soil

NASA Astrophysics Data System (ADS)

Kukade, Pranav

Agricultural mulch films that are used to cover soil of crop rows contribute to earlier maturation of crops and higher yield. Incineration and landfill disposals are the most common means of disposal of the incumbent polyethylene (PE) mulch films; however, these are not environment friendly options. Biodegradable mulch films that can be rototilled into the soil after crop harvest are a promising alternative to offset problems such as landfill disposal, film retrieval and disposal costs. In this study, an in-house laboratory scale test method was developed in which the rate of disintegration, as a result of biodegradation of films based on polyhydroxybutanoic acid (PHB) copolymers was investigated in a soil environment using the residual weight loss method. The influence of soil composition, moisture levels in the soil, and industry-standard anti-microbial additive in the film composition on the rate of disintegration of PHB copolymer films was investigated. The soil composition has significant effect on the disintegration kinetics of PHB copolymer films, since the increasing compost levels in the soil lowered the rate of disintegration of the film. Also, with the increase in moisture level up to a threshold limit, the microbial activity and, hence, the rate of disintegration increased. Lastly, the developed lab-scale test protocol was found to be sensitive to even small concentrations of industry-standard antimicrobial additive in the film composition.

Organophilic clays as a tracer to determine Erosion processes

NASA Astrophysics Data System (ADS)

Mentler, A.; Strauss, P.; Schomakers, J.; Hann, S.; Köllensberger, G.; Ottner, F.

2009-04-01

In recent years the use of new tracing techniques to measure soil erosion has gained attention. Beside long time existing isotopic methods the use of rare earth elements has been reported. We wanted to contribute to the efforts of obtaining better methods for determination surface soil movement and tested a novel method using organophilic clays as a tracer for erosion related studies. At present tests to extract organophilic clays from soil have been performed successfully using an Industrial produced organophilic bentonite (Tixogel TVZ, Süd-Chemie) treated with quaternary ammonium surfactants. A liquid extraction method with barium ions (Ba2+) and methanol was used to extract the n-alkyl ammonium compounds from the inter crystal layers of the modified Bentonite. To increase extraction efficiency, an ultrasound device was used (UW 2200 Bandelin, 10.000 cycles per second, vibration amplitude 54 µm, sonification time of one minute). This procedure lead to a recovery rate of about 85% for the organophilic bentonite. This was clearly superior to alternative extraction methods such as acetonitrile in different mixing ratios. Quantification of the extracted surfactants was performed via high performance liquid chromatography - mass spectrometry (HPLC-MS, Agilent 1200 SL HPLC and 6220 time-of-flight MS). The mass spectra of this industrial produced organophilic clay mineral showed four different molecular masses (M+H+ of 304.30, 332.33, 360.36 and 388.39. The four substances could be separated by HPLC (20 x 2 mm Zorbax C18 reversed phase column, 0.5 mL/min isocratic flow with 90% acetonitrile and 0.1% formic acid in water, run time of 7 minutes). The linear working range of the method was 5 to 1000 µg/L, with a limit of quantification of 1 µg/L n-alkyl ammonium compound. All four compounds of the Tixogel were extracted with identical extraction efficiencies and are hence suitable for accurate quantification procedures. Next steps of the methodology to develop are the application of the organophilic clays in an indoor rainfall simulation experiment at a small scale of 2 m². At present the methodology has been tested only for one particular soil. Future tests will be performed to see if the chosen methodology needs soil specific treatment when applied to more soils of different textural composition.

A Field and Laboratory Based Assessment of the Potential of High Frequency Ground Penetrating Radar (HFGPR) to Evaluate the Presence and Spatial Variabilty of Hydrophobic Soil Layers

NASA Astrophysics Data System (ADS)

Weirich, F. H.; Neumann, W.; Campbell, D.

2017-12-01

The presence of fire related hydrophobic (water repellant) soil layers in a wide range of environmental settings can result in greatly increased rates of storm runoff and erosion. In many situations this can contribute to the generation of debris and/or hyperconcentrated flows. While the role of hydrophobic soils in greatly increasing sediment production in such situations is known, the ability to predict the volume of sediment that will be generated by specific storm events has been limited, in part, by limits on the ability to assess the characteristics of hydrophobic soil layers. At present, the most widely accepted method of assessing the presence, strength, extent and persistence of hydrophobic soil layers requires the performance of an in situ water drop penetration test (WDPT). This approach, while effective on a local site, is labor and time intensive and can be difficult to employ on a watershed or even slope wide basis. As part of a wider research effort to develop more effective methods of evaluating the characteristics of hydrophobic soils a combined field and laboratory based program has been undertaken to evaluate the capability of higher frequency ground penetrating radar (HFGPR) to detect and map out the spatial extent, strength, and persistence of hydrophobic soil layers. This has involved the testing of HFGPR systems at several field site in burnt watersheds in Southern California as well as a program of laboratory tests on samples of fire impacted soils collected from the same watersheds. The field tests were undertaken on sites ranging from a location that had burnt a few weeks earlier to locations where over 5 years had passed since a burn took place. Laboratory samples of soils were taken from the same range of sites and used in the laboratory tests. In parallel with the HFGPR testing WDPT's were used to confirm the findings of the HFGPR approach. Both the field and laboratory results indicate that the use of HFGPR, under appropriate soil moisture conditions, is capable of mapping out the presence, spatial extent, and persistence of hydrophobic soil layers. Layers at depth ranging from 1-6 cm were successfully mapped. The persistence of layers on some sites 5 years after a burn were also able to be measured using this approach. Work to further refine both the approach and its limitations is ongoing.

Isolation of antimicrobial producing Actinobacteria from soil samples.

PubMed

Elbendary, Afaf Ahmed; Hessain, Ashgan Mohamed; El-Hariri, Mahmoud Darderi; Seida, Ahmed Adel; Moussa, Ihab Mohamed; Mubarak, Ayman Salem; Kabli, Saleh A; Hemeg, Hassan A; El Jakee, Jakeen Kamal

2018-01-01

Emergence of multidrug resistant bacteria has made the search for novel bioactive compounds from natural and unexplored habitats a necessity. Actinobacteria have important bioactive substances. The present study investigated antimicrobial activity of Actinobacteria isolated from soil samples of Egypt. One hundred samples were collected from agricultural farming soil of different governorates. Twelve isolates have produced activity against the tested microorganisms ( S. aureus , Bacillus cereus , E. coli , K. pneumoniae , P. aeruginosa , S. Typhi, C. albicans , A. niger and A. flavus ). By VITEK 2 system version: 07.01 the 12 isolates were identified as Kocuria kristinae , Kocuria rosea , Streptomyces griseus , Streptomyces flaveolus and Actinobacteria . Using ethyl acetate extraction method the isolates culture's supernatants were tested by diffusion method against indicator microorganisms. These results indicate that Actinobacteria isolated from Egypt farms could be sources of antimicrobial bioactive substances.

A toxicity test in artificial soil based on the life-history strategy of the nematode Plectus acuminatus

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

Kammenga, J.E.; Van Koert, P.H.G.; Riksen, J.A.G.

1996-05-01

The ecological risk assessment of toxicants in soil requires reproducible and relevant test systems using a wide range of species. To supplement present test methods from the Organisation of Economic Cooperation and Development (OECD) in artificial soil with earthworms and springtails, a toxicity test in OECD artificial soil has been developed using the bacterivorous nematode Plectus acuminatus (Bastian, 1865) (Nematoda; Plectidae). The juvenile to adult ratio was used as a test parameter since previous life-cycle studies pointed out that fitness of P. acuminatus was strongly determined by changes in both reproduction and juvenile survival. Optimal conditions for the performance ofmore » nematodes in OECD artificial soil were determined (pH{sub KCl} = 5.5, temperature = 20C, and a moisture content of 70% dry wt. artificial soil), and tests were conducted with cadmium, copper, and pentachlorophenol. After an exposure period of 3 weeks the EC50 for cadmium was 321.0 {+-} 1.7 mg/kg dry wt., and the no-observed-effect concentration (NOEC) was 32 mg/kg dry wt. The EC50 for pentachlorophenol was 47.9 {+-} 1.2 mg/kg dry wt., and the NOEC was <10 mg/kg dry wt. For copper the EC50 was 162 {+-} 0.2 mg/kg dry wt., and the NOEC was 32 mg/kg dry wt. It is concluded that the nematode test may well supplement current coil test systems using earthworms and springtails.« less

An innovative method for the solidification/stabilization of PAHs-contaminated soil using sulfonated oil.

PubMed

Ma, Fujun; Wu, Bin; Zhang, Qian; Cui, Deshan; Liu, Qingbing; Peng, Changsheng; Li, Fasheng; Gu, Qingbao

2018-02-15

Stabilization/solidification (S/S) has been successfully employed in many superfund sites contaminated with organic materials. However, this method's long-term effectiveness has not been fully evaluated and the increase in soil volume following treatment is unfavorable to follow-up disposal. The present study developed a novel method for the S/S of PAHs-contaminated soil with the facilitation of sulfonated oil (SO). Adding SO significantly improved the unconfined compressive strength (UCS) values of Portland cement and activated carbon (PC-AC) treated soil samples, and the UCS values of the soil sample treated with 0.02% of SO were up to 2.3 times higher than without SO addition. When the soil was treated with PC-AC-SO, the PAHs leaching concentrations were 14%-25% of that in leachates of the control soil, and high molecular weight PAHs including benzo(a)pyrene were rarely leached. Freeze/thaw durability tests reveal that the leachability of PAHs was not influenced by freeze-thaw cycles. The UCS values of PC-AC-SO treated soil samples were 2.2-3.4 times greater than those of PC-AC treated soil samples after 12 freeze-thaw cycles. The PC-AC-SO treated soils resist disintegration better when compared to the PC-AC treated soils. The SEM micrographs reveal that the soils' compactness was significantly improved when treated with SO. Copyright © 2017 Elsevier B.V. All rights reserved.

Selected papers in the hydrologic sciences 1984; July 1984

USGS Publications Warehouse

Meyer, Eric L.

1984-01-01

The rapid, accurate measurement of the oxygen content of soil gas in the unsaturated zone or dissolved oxygen in soil water in the saturated zone can be useful in wetland vegetation studies. A method has been devised and tested in the Great Dismal Swamp, a wetland with fine silt-clay and organic soils, that appears to provide good results. A 60-milliliter sample of soil gas or water is withdrawn from permanently installed chambers at various depths in the soil profile. The oxygen concentration of air samples is measured with a specially constructed analyzer cell fitted to the polarographic oxygen electrode of a portable oxygen meter. The dissolved oxygen concentration of water samples is measured directly with the oxygen electrode while stirring the sample in a 32-milliliter glass bottle with a portable magnetic stirrer. Field tests with duplicate chamber installations showed that consistent results are obtained for soil gas and water.

Reference guide for the soil compactor analyzer.

DOT National Transportation Integrated Search

2009-07-01

The Soil Compactor Analyzer (SCA) attaches to the automatic tamper used for Test Methods Tex-113-E and 114-E and uses rapid sampling of the hammer displacement to measure impact velocity. With the known mass of the hammer and the determined velocity,...

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

Fitzgerald, D.; Lanno, R.P.; Farwell, A.

Although methods for standardized toxicity tests with earthworms exist, many of the test parameters and conditions have not been validated in actual tests and with different species of worms. This study evaluated the toxicity of pentachlorophenol (PCP) to three species of earthworms, Lumbricus terrestris, Eisenia fetida, and Eudrilus eugeniae using various methods of data analysis and body residues. Tests were conducted in artificial soil for a period of 28 days or until an Acute Lethality Threshold (ALT) was reached. An intensive temporal sampling regime was applied to generate sufficient data for the accurate estimation of ALTs using both LC50/time andmore » time-to-death/soil concentration methods of data analysis. L. terrestris was tested at 15 C, E. eugeniae at 24 C, and E. fetida at both temperatures. Total body residues of PCP were measured by GC following cryogenic separation of the lipid fraction of the worm. ALTs were significantly different between E. fetida and the two larger species of worms. No effect of temperature on the ALT for E. fetida was observed, although the time taken to reach the ALT increased at the lower temperature. The relationship of PCP residues at mortality will be discussed in terms of the effects of species, body size and temperature. Limitations of the artificial soil based upon growth curves of worms will also be examined.« less

Some Remarks on Practical Aspects of Laboratory Testing of Deep Soil Mixing Composites Achieved in Organic Soils

NASA Astrophysics Data System (ADS)

Kanty, Piotr; Rybak, Jarosław; Stefaniuk, Damian

2017-10-01

This paper presents the results of laboratory testing of organic soil-cement samples are presented in the paper. The research program continues previously reported the authors’ experiences with cement-fly ash-soil sample testing. Over 100 of compression and a dozen of tension tests have been carried out altogether. Several samples were waiting for failure test for over one year after they were formed. Several factors, like: the large amount of the tested samples, a long observation time, carrying out the tests in complex cycles of loading and the possibility of registering the loads and deformation in the axial and lateral direction - have made it possible to take into consideration numerous interdependencies, three of which have been presented in this work: the increments of compression strength, the stiffness of soil-cement in relation to strength and the tensile strength. Compressive strength, elastic modulus and tensile resistance of cubic samples were examined. Samples were mixed and stored in the laboratory conditions. Further numerical analysis in the Finite Element Method numerical code Z_Soil, were performed on the basis of laboratory test results. Computations prove that cement-based stabilization of organic soil brings serious risks (in terms of material capacity and stiffness) and Deep Soil Mixing technology should not be recommended for achieving it. The numerical analysis presented in the study below includes only one type of organic and sandy soil and several possible geometric combinations. Despite that, it clearly points to the fact that designing the DSM columns in the organic soil may be linked with a considerable risk and the settlement may reach too high values. During in situ mixing, the organic material surrounded by sand layers surely mixes with one another in certain areas. However, it has not been examined and it is difficult to assume such mixing already at the designing stage. In case of designing the DSM columns which goes through a thin layer of organic soil it is recommended to carry out each time the core drilling which checks the degree of material mixing and their strength.

Digital mapping of soil properties in Canadian managed forests at 250 m of resolution using the k-nearest neighbor method

NASA Astrophysics Data System (ADS)

Mansuy, N. R.; Paré, D.; Thiffault, E.

2015-12-01

Large-scale mapping of soil properties is increasingly important for environmental resource management. Whileforested areas play critical environmental roles at local and global scales, forest soil maps are typically at lowresolution.The objective of this study was to generate continuous national maps of selected soil variables (C, N andsoil texture) for the Canadian managed forest landbase at 250 m resolution. We produced these maps using thekNN method with a training dataset of 538 ground-plots fromthe National Forest Inventory (NFI) across Canada,and 18 environmental predictor variables. The best predictor variables were selected (7 topographic and 5 climaticvariables) using the Least Absolute Shrinkage and Selection Operator method. On average, for all soil variables,topographic predictors explained 37% of the total variance versus 64% for the climatic predictors. Therelative root mean square error (RMSE%) calculated with the leave-one-out cross-validation method gave valuesranging between 22% and 99%, depending on the soil variables tested. RMSE values b 40% can be considered agood imputation in light of the low density of points used in this study. The study demonstrates strong capabilitiesfor mapping forest soil properties at 250m resolution, compared with the current Soil Landscape of CanadaSystem, which is largely oriented towards the agricultural landbase. The methodology used here can potentiallycontribute to the national and international need for spatially explicit soil information in resource managementscience.

Legacy Phosphorus Effect and Need to Re-calibrate Soil Test P Methods for Organic Crop Production.

NASA Astrophysics Data System (ADS)

Dao, Thanh H.; Schomberg, Harry H.; Cavigelli, Michel A.

2015-04-01

Phosphorus (P) is a required nutrient for the normal development and growth of plants and supplemental P is needed in most cultivated soils. Large inputs of cover crop residues and nutrient-rich animal manure are added to supply needed nutrients to promote the optimal production of organic grain crops and forages. The effects of crop rotations and tillage management of the near-surface zone on labile phosphorus (P) forms were studied in soil under conventional and organic crop management systems in the mid-Atlantic region of the U.S. after 18 years due to the increased interest in these alternative systems. Soil nutrient surpluses likely caused by low grain yields resulted in large pools of exchangeable phosphate-P and equally large pools of enzyme-labile organic P (Po) in soils under organic management. In addition, the difference in the P loading rates between the conventional and organic treatments as guided by routine soil test recommendations suggested that overestimating plant P requirements contributed to soil P surpluses because routine soil testing procedures did not account for the presence and size of the soil enzyme-labile Po pool. The effect of large P additions is long-lasting as they continued to contribute to elevated soil total bioactive P concentrations 12 or more years later. Consequently, accurate estimates of crop P requirements, P turnover in soil, and real-time plant and soil sensing systems are critical considerations to optimally manage manure-derived nutrients in organic crop production.

Mobility of arsenic and its compounds in soil and soil solution: the effect of soil pretreatment and extraction methods.

PubMed

Száková, J; Tlustos, P; Goessler, W; Frková, Z; Najmanová, J

2009-12-30

The effect of soil extraction procedures and/or sample pretreatment (drying, freezing of the soil sample) on the extractability of arsenic and its compounds was tested. In the first part, five extraction procedures were compared with following order of extractable arsenic portions: 2M HNO(3)>0.43 M CH(3)COOH>or=0.05 M EDTA>or=Mehlich III (0.2M CH(3)COOH+0.25 M NH(4)NO(3)+0.013 M HNO(3)+0.015 M NH(4)F+0.001 M EDTA) extraction>water). Additionally, two methods of soil solution sampling were compared, centrifugation of saturated soil and the use of suction cups. The results showed that different sample pretreatments including soil solution sampling could lead to different absolute values of mobile arsenic content in soils. However, the interpretation of the data can lead to similar conclusions as apparent from the comparison of the soil solution sampling methods (r=0.79). For determination of arsenic compounds mild extraction procedures (0.05 M (NH(4))(2)SO(4), 0.01 M CaCl(2), and water) and soil solution sampling using suction cups were compared. Regarding the real soil conditions the extraction of fresh samples and/or in situ collection of soil solution are preferred among the sample pretreatments and/or soil extraction procedures. However, chemical stabilization of the solutions should be allowed and included in the analytical procedures for determination of individual arsenic compounds.

Adsorption-desorption behavior of atrazine on agricultural soils in China.

PubMed

Yue, Lin; Ge, ChengJun; Feng, Dan; Yu, Huamei; Deng, Hui; Fu, Bomin

2017-07-01

Adsorption and desorption are important processes that affect atrazine transport, transformation, and bioavailability in soils. In this study, the adsorption-desorption characteristics of atrazine in three soils (laterite, paddy soil and alluvial soil) were evaluated using the batch equilibrium method. The results showed that the kinetics of atrazine in soils was completed in two steps: a "fast" adsorption and a "slow" adsorption and could be well described by pseudo-second-order model. In addition, the adsorption equilibrium isotherms were nonlinear and were well fitted by Freundlich and Langmuir models. It was found that the adsorption data on laterite, and paddy soil were better fitted by the Freundlich model; as for alluvial soil, the Langmuir model described it better. The maximum atrazine sorption capacities ranked as follows: paddy soil>alluvial soil>laterite. Results of thermodynamic calculations indicated that atrazine adsorption on three tested soils was spontaneous and endothermic. The desorption data showed that negative hysteresis occurred. Furthermore, lower solution pH value was conducive to the adsorption of atrazine in soils. The atrazine adsorption in these three tested soils was controlled by physical adsorption, including partition and surface adsorption. At lower equilibrium concentration, the atrazine adsorption process in soils was dominated by surface adsorption; while with the increase of equilibrium concentration, partition was predominant. Copyright © 2016. Published by Elsevier B.V.

Measuring air-water interfacial area for soils using the mass balance surfactant-tracer method.

PubMed

Araujo, Juliana B; Mainhagu, Jon; Brusseau, Mark L

2015-09-01

There are several methods for conducting interfacial partitioning tracer tests to measure air-water interfacial area in porous media. One such approach is the mass balance surfactant tracer method. An advantage of the mass-balance method compared to other tracer-based methods is that a single test can produce multiple interfacial area measurements over a wide range of water saturations. The mass-balance method has been used to date only for glass beads or treated quartz sand. The purpose of this research is to investigate the effectiveness and implementability of the mass-balance method for application to more complex porous media. The results indicate that interfacial areas measured with the mass-balance method are consistent with values obtained with the miscible-displacement method. This includes results for a soil, for which solid-phase adsorption was a significant component of total tracer retention. Copyright © 2015 Elsevier Ltd. All rights reserved.

Determination of molybenum in soils and rocks: A geochemical semimicro field method

USGS Publications Warehouse

Ward, F.N.

1951-01-01

Reconnaissance work in geochemical prospecting requires a simple, rapid, and moderately accurate method for the determination of small amounts of molybdenum in soils and rocks. The useful range of the suggested procedure is from 1 to 32 p.p.m. of molybdenum, but the upper limit can be extended. Duplicate determinations on eight soil samples containing less than 10 p.p.m. of molybdenum agree within 1 p.p.m., and a comparison of field results with those obtained by a conventional laboratory procedure shows that the method is sufficiently accurate for use in geochemical prospecting. The time required for analysis and the quantities of reagents needed have been decreased to provide essentially a "test tube" method for the determination of molybdenum in soils and rocks. With a minimum amount of skill, one analyst can make 30 molybdenum determinations in an 8-hour day.

Estimating soil matric potential in Owens Valley, California

USGS Publications Warehouse

Sorenson, Stephen K.; Miller, Reuben F.; Welch, Michael R.; Groeneveld, David P.; Branson, Farrel A.

1989-01-01

Much of the floor of Owens Valley, California, is covered with alkaline scrub and alkaline meadow plant communities, whose existence is dependent partly on precipitation and partly on water infiltrated into the rooting zone from the shallow water table. The extent to which these plant communities are capable of adapting to and surviving fluctuations in the water table depends on physiological adaptations of the plants and on the water content, matric potential characteristics of the soils. Two methods were used to estimate soil matric potential in test sites in Owens Valley. The first, the filter-paper method, uses water content of filter papers equilibrated to water content of soil samples taken with a hand auger. The previously published calibration relations used to estimate soil matric potential from the water content of the filter papers were modified on the basis of current laboratory data. The other method of estimating soil matric potential was a modeling approach based on data from this and previous investigations. These data indicate that the base-10 logarithm of soil matric potential is a linear function of gravimetric soil water content for a particular soil. The slope and intercepts of this function vary with the texture and saturation capacity of the soil. Estimates of soil water characteristic curves were made at two sites by averaging the gravimetric soil water content and soil matric potential values from multiple samples at 0.1-m depth intervals derived by using the hand auger and filter-paper method and entering these values in the soil water model. The characteristic curves then were used to estimate soil matric potential from estimates of volumetric soil water content derived from neutron-probe readings. Evaluation of the modeling technique at two study sites indicated that estimates of soil matric potential within 0.5 pF units of the soil matric potential value derived by using the filter-paper method could be obtained 90 to 95 percent of the time in soils where water content was less than field capacity. The greatest errors occurred at depths where there was a distinct transition between soils of different textures.

Airstream fractionation of vesicular-arbuscular mycorrhizal fungi: concentration and enumeration of propagules.

PubMed

Tommerup, I C

1982-09-01

Spores and fragments of vesicular-arbuscular mycorrhizal fungi in dry soils were concentrated up to 100-fold when the soils were partitioned by fluidization and elutriation with a series of upward airstreams at progressively increasing velocities. The propagules were transported with the finer soil particles according to their equivalent spherical diameters. The system was used to predict the transport of propagules by wind. Concentrated propagules were rapidly separated from the soil particles in each soil fraction by an aqueous flotation method. The technique is proposed as a quantitative method for estimating the numbers of spores and fragments of mycorrhizae. The scheme includes a viability test that was used to differentiate between potentially infective propagules and those that were either dormant or incapable of regrowth.

A comparison of reliability of soil Cd determination by standard spectrometric methods

PubMed Central

McBride, M.B.

2015-01-01

Inductively coupled plasma emission spectrometry (ICP-OES) is the most common method for determination of soil Cd, yet spectral and matrix interferences affect measurements at the available analytical wavelengths for this metal. This study evaluated the severity of the interference over a range of total soil Cd by comparing ICP-OES and ICP-MS measurements of Cd in acid digests. ICP-OES using the emission at 226.5 nm generally unable to quantify soil Cd at low (near-background) levels, and gave unreliable values compared to ICP-MS. Using the line at 228.nm, a marked positive bias in Cd measurement (relative to the 226.5 nm measurement) was attributable to As interference even at soil As concentrations below 10 mg/kg. This spectral interference in ICP-OES was severe in As-contaminated orchard soils, giving a false value for soil total Cd near 2 mg kg−1 when soil As was 100–150 mg kg−1. In attempting to avoid these ICP emission-specific interferences, we evaluated a method to estimate total soil Cd using 1 M HNO3 extraction followed by determination of Cd by flame atomic absorption (FAA), either with or without pre-concentration of Cd using an Aliquat-heptanone extractant. The 1 M HNO3 extracted an average of 82% of total soil Cd. The FAA method had no significant interferences, and estimated the total Cd concentrations in all soils tested with acceptable accuracy. For Cd-contaminated soils, the Aliquat-heptanone pre-concentration step was not necessary, as FAA sensitivity was adequate for quantification of extractable soil Cd and reliable estimation of total soil Cd. PMID:22031569

Predicting Nitrogen Availability to Rice: II. Assessing Available Nitrogen in Silt Loams With Different Previous Year Crop History

Treesearch

J. L. Sims; B. G. Blackmon

1967-01-01

Soil test method s that measure NH4+-N in silt 100ms before and after incubation under waterlogged conditions were evaluated as predictors of N availability to 'Nato' rice (Oriza sativa L.) frown in the greenhouse. Eighteen soils for each of five previous year crop histories were utilized. An soils were from crop rotations containing rice....

Nematodes Relevance in Soil Quality Management and their Significance as Biomarkers in Aquatic Substrates: Review.

PubMed

Akpheokhai, Leonard I; Oribhabor, Blessing J

2016-01-01

The interaction of man with the ecosystem is a major factor causing environmental pollution and its attendant consequences such as climate change in our world today. Patents relating to nematodes' relevance in soil quality management and their significance as biomarkers in aquatic substrates were reviewed. Nematodes are useful in rapid, easy and inexpensive method for testing the toxicity of substance (e.g. aquatic substrates). This review paper sets out to examine and discuss the issue of soil pollution, functions of nematodes in soil and aquatic substrates as well as bio-indicators in soil health management in terrestrial ecology. The information used were on the basis of secondary sources from previous research. It is abundantly clear that the population dynamics of plant parasitic or free-living nematodes have useful potentials as biomonitor for soil health and other forms of environmental contamination through agricultural activities, industrial pollution and oil spillage, and the analysis of nematode community structure could be used as complementary information obtained from conventional soil testing approaches.

FEASIBILITY OF HYDRAULIC FRACTURING OF SOILS TO IMPROVE REMEDIAL ACTIONS

EPA Science Inventory

Hydraulic fracturing, a technique commonly used to increase the yields of oil wells, could improve the effectiveness of several methods of in situ remediation. This project consisted of laboratory and field tests in which hydraulic fractures were created in soil. Laboratory te...

40 CFR 412.37 - Additional measures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... STANDARDS CONCENTRATED ANIMAL FEEDING OPERATIONS (CAFO) POINT SOURCE CATEGORY Dairy Cows and Cattle Other... application; (4) Test methods used to sample and analyze manure, litter, process waste water, and soil; (5) Results from manure, litter, process waste water, and soil sampling; (6) Explanation of the basis for...

40 CFR 412.37 - Additional measures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... STANDARDS CONCENTRATED ANIMAL FEEDING OPERATIONS (CAFO) POINT SOURCE CATEGORY Dairy Cows and Cattle Other... application; (4) Test methods used to sample and analyze manure, litter, process waste water, and soil; (5) Results from manure, litter, process waste water, and soil sampling; (6) Explanation of the basis for...

40 CFR 412.37 - Additional measures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... STANDARDS CONCENTRATED ANIMAL FEEDING OPERATIONS (CAFO) POINT SOURCE CATEGORY Dairy Cows and Cattle Other... application; (4) Test methods used to sample and analyze manure, litter, process waste water, and soil; (5) Results from manure, litter, process waste water, and soil sampling; (6) Explanation of the basis for...

Contribution to Estimating Bearing Capacity of Pile in Clayey Soils

NASA Astrophysics Data System (ADS)

Drusa, Marián; Gago, Filip; Vlček, Jozef

2016-12-01

The estimation of real geotechnical parameters is key factor for safe and economic design of geotechnical structures. One of these are pile foundations, which require proper design and evaluation due to accessing more deep foundation soil and because remediation work of not bearable piles or broken piles is a crucial operation. For this reason, geotechnical field testing like cone penetration test (CPT), standard penetration (SPT) or dynamic penetration test (DP) are realized in order to receive continuous information about soil strata. Comparing with rotary core drilling type of survey with sampling, these methods are more progressive. From engineering geologist point of view, it is more important to know geological characterization of locality but geotechnical engineers have more interest above the real geotechnical parameters of foundation soils. The role of engineering geologist cannot be underestimated because important geological processes in origin or during history can explain behaviour of a geological environment. In effort to streamline the survey, investigation by penetration tests is done as it is able to provide enough information for designers. This paper deals with actual trends in pile foundation design; because there are no new standards and usable standards are very old. Estimation of the bearing capacity of a single pile can be demonstrated on the example of determination of the cone factor Nk from CPT testing. Then results were compared with other common methods.

Potential microbial risk factors related to soil amendments and irrigation water of potato crops.

PubMed

Selma, M V; Allende, A; López-Gálvez, F; Elizaquível, P; Aznar, R; Gil, M I

2007-12-01

This study assesses the potential microbial risk factors related to the use of soil amendments and irrigation water on potato crops, cultivated in one traditional and two intensive farms during two harvest seasons. The natural microbiota and potentially pathogenic micro-organisms were evaluated in the soil amendment, irrigation water, soil and produce. Uncomposted amendments and residual and creek water samples showed the highest microbial counts. The microbial load of potatoes harvested in spring was similar among the tested farms despite the diverse microbial levels of Listeria spp. and faecal coliforms in the potential risk sources. However, differences in total coliform load of potato were found between farms cultivated in the autumn. Immunochromatographic rapid tests and the BAM's reference method (Bacteriological Analytical Manual; AOAC International) were used to detect Escherichia coli O157:H7 from the potential risk sources and produce. Confirmation of the positive results by polymerase chain reaction procedures showed that the immunochromatographic assay was not reliable as it led to false-positive results. The potentially pathogenic micro-organisms of soil amendment, irrigation water and soil samples changed with the harvest seasons and the use of different agricultural practices. However, the microbial load of the produce was not always influenced by these risk sources. Improvements in environmental sample preparation are needed to avoid interferences in the use of immunochromatographic rapid tests. The potential microbial risk sources of fresh produce should be regularly controlled using reliable detection methods to guarantee their microbial safety.

Rapid Estimation of TPH Reduction in Oil-Contaminated Soils Using the MED Method

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

Edenborn, H.M.; Zenone, V.A.

2007-09-01

Oil-contaminated soil and sludge generated during federal well plugging activities in northwestern Pennsylvania are currently remediated on small landfarm sites in lieu of more expensive landfill disposal. Bioremediation success at these sites in the past has been gauged by the decrease in total petroleum hydrocarbon (TPH) concentrations to less than 10,000 mg/kg measured using EPA Method 418.1. We tested the “molarity of ethanol droplet” (MED) water repellency test as a rapid indicator of TPH concentration in soil at one landfarm near Bradford, PA. MED was estimated by determining the minimum ethanol concentration (0 – 6 M) required to penetrate air-driedmore » and sieved soil samples within 10 sec. TPH in soil was analyzed by rapid fluorometric analysis of methanol soil extracts, which correlated well with EPA Method 1664. Uncontaminated landfarm site soil amended with increasing concentrations of waste oil sludge showed a high correlation between MED and TPH. MED values exceeded the upper limit of 6 M as TPH estimates exceed ca. 25,000 mg/kg. MED and TPH at the land farm were sampled monthly during summer months over two years in a grid pattern that allowed spatial comparisons of site remediation effectiveness. MED and TPH decreased at a constant rate over time and remained highly correlated. Inexpensive alternatives to reagent-grade ethanol gave comparable results. The simple MED approach served as an inexpensive alternative to the routine laboratory analysis of TPH during the monitoring of oily waste bioremediation at this landfarm site.« less

Bioaccessibility tests accurately estimate bioavailability of lead to quail

USGS Publications Warehouse

Beyer, W. Nelson; Basta, Nicholas T; Chaney, Rufus L.; Henry, Paula F.; Mosby, David; Rattner, Barnett A.; Scheckel, Kirk G.; Sprague, Dan; Weber, John

2016-01-01

Hazards of soil-borne Pb to wild birds may be more accurately quantified if the bioavailability of that Pb is known. To better understand the bioavailability of Pb to birds, we measured blood Pb concentrations in Japanese quail (Coturnix japonica) fed diets containing Pb-contaminated soils. Relative bioavailabilities were expressed by comparison with blood Pb concentrations in quail fed a Pb acetate reference diet. Diets containing soil from five Pb-contaminated Superfund sites had relative bioavailabilities from 33%-63%, with a mean of about 50%. Treatment of two of the soils with phosphorus significantly reduced the bioavailability of Pb. Bioaccessibility of Pb in the test soils was then measured in six in vitro tests and regressed on bioavailability. They were: the “Relative Bioavailability Leaching Procedure” (RBALP) at pH 1.5, the same test conducted at pH 2.5, the “Ohio State University In vitro Gastrointestinal” method (OSU IVG), the “Urban Soil Bioaccessible Lead Test”, the modified “Physiologically Based Extraction Test” and the “Waterfowl Physiologically Based Extraction Test.” All regressions had positive slopes. Based on criteria of slope and coefficient of determination, the RBALP pH 2.5 and OSU IVG tests performed very well. Speciation by X-ray absorption spectroscopy demonstrated that, on average, most of the Pb in the sampled soils was sorbed to minerals (30%), bound to organic matter (24%), or present as Pb sulfate (18%). Additional Pb was associated with P (chloropyromorphite, hydroxypyromorphite and tertiary Pb phosphate), and with Pb carbonates, leadhillite (a lead sulfate carbonate hydroxide), and Pb sulfide. The formation of chloropyromorphite reduced the bioavailability of Pb and the amendment of Pb-contaminated soils with P may be a thermodynamically favored means to sequester Pb.

Improved hydrological model parametrization for climate change impact assessment under data scarcity - The potential of field monitoring techniques and geostatistics.

PubMed

Meyer, Swen; Blaschek, Michael; Duttmann, Rainer; Ludwig, Ralf

2016-02-01

According to current climate projections, Mediterranean countries are at high risk for an even pronounced susceptibility to changes in the hydrological budget and extremes. These changes are expected to have severe direct impacts on the management of water resources, agricultural productivity and drinking water supply. Current projections of future hydrological change, based on regional climate model results and subsequent hydrological modeling schemes, are very uncertain and poorly validated. The Rio Mannu di San Sperate Basin, located in Sardinia, Italy, is one test site of the CLIMB project. The Water Simulation Model (WaSiM) was set up to model current and future hydrological conditions. The availability of measured meteorological and hydrological data is poor as it is common for many Mediterranean catchments. In this study we conducted a soil sampling campaign in the Rio Mannu catchment. We tested different deterministic and hybrid geostatistical interpolation methods on soil textures and tested the performance of the applied models. We calculated a new soil texture map based on the best prediction method. The soil model in WaSiM was set up with the improved new soil information. The simulation results were compared to standard soil parametrization. WaSiMs was validated with spatial evapotranspiration rates using the triangle method (Jiang and Islam, 1999). WaSiM was driven with the meteorological forcing taken from 4 different ENSEMBLES climate projections for a reference (1971-2000) and a future (2041-2070) times series. The climate change impact was assessed based on differences between reference and future time series. The simulated results show a reduction of all hydrological quantities in the future in the spring season. Furthermore simulation results reveal an earlier onset of dry conditions in the catchment. We show that a solid soil model setup based on short-term field measurements can improve long-term modeling results, which is especially important in ungauged catchments. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluating specificity of sequential extraction for chemical forms of lead in artificially-contaminated and field-contaminated soils.

PubMed

Tai, Yiping; McBride, Murray B; Li, Zhian

2013-03-30

In the present study, we evaluated a commonly employed modified Bureau Communautaire de Référence (BCR test) 3-step sequential extraction procedure for its ability to distinguish forms of solid-phase Pb in soils with different sources and histories of contamination. When the modified BCR test was applied to mineral soils spiked with three forms of Pb (pyromorphite, hydrocerussite and nitrate salt), the added Pb was highly susceptible to dissolution in the operationally-defined "reducible" or "oxide" fraction regardless of form. When three different materials (mineral soil, organic soil and goethite) were spiked with soluble Pb nitrate, the BCR sequential extraction profiles revealed that soil organic matter was capable of retaining Pb in more stable and acid-resistant forms than silicate clay minerals or goethite. However, the BCR sequential extraction for field-collected soils with known and different sources of Pb contamination was not sufficiently discriminatory in the dissolution of soil Pb phases to allow soil Pb forms to be "fingerprinted" by this method. It is concluded that standard sequential extraction procedures are probably not very useful in predicting lability and bioavailability of Pb in contaminated soils. Copyright © 2013 Elsevier B.V. All rights reserved.

Mapping of soil erosion and redistribution on two agricultural areas in Czech Republic by using of magnetic parameters.

NASA Astrophysics Data System (ADS)

Kapicka, Ales; Stejskalova, Sarka; Grison, Hana; Petrovsky, Eduard; Jaksik, Ondrej; Kodesova, Radka

2015-04-01

Soil erosion is one of the major concerns in sustainability of agricultural systems in different areas. Therefore there is a need to develop suitable innovative indirect methods of soil survey. One of this methods is based on well established differentiation in magnetic signature with depth in soil profile. Magnetic method can be applied in the field as well as in the laboratory on collected soil samples. The aim of this study is to evaluate suitability of magnetic method to assess soil degradation and construct maps of cumulative soil loss due to erosion at two morphologically diverse areas with different soil types. Dominant soil unit in the first locality (Brumovice) is chernozem, which is gradually degraded on slopes to regosols. In the second site (Vidim), the dominant soil unit is luvisol, gradualy transformed to regosol due to erosion. Field measurements of magnetic susceptibility were carried out on regular grid, resulting in 101 data points in Brumovice and 65 in Vidim locality. Mass specific magnetic susceptibility χ and its frequency dependence χFD was used to estimate the significance of SP ferrimagnetic particles of pedogenic origin in top soil horizons. Strong correlation was found between the volume magnetic susceptibility (field measurement) and mass- specific magnetic susceptibility measured in the laboratory (Kapicka et al 2013). Values of magnetic susceptibility are spatially distributed depending on terrain position. Higher values were measured at the flat parts (where the original topsoil horizon remained). The lowest values magnetic susceptibility were obtained on the steep valley sides. Here the original topsoil was eroded and mixed by tillage with the soil substrate (loess). Positive correlation between the organic carbon content and volume magnetic susceptibility (R2= 0.89) was found for chernozem area. The differences between the values of susceptibility in the undisturbed soil profile and the magnetic signal after uniform mixing of the soil material as a result of tillage and erosion are fundamental for the estimation of soil loss in the studied test field (Royall 2001). The map of soil erosion shows maximum removal of soil material in the steepest parts of the testing localities. The magnetic method is very well suitable for mapping at the chernozem locality (Brumovice) and measurement of soil magnetic susceptibility is in this case a useful and fast technique for quantitative estimation of soil loss caused by erosion and tillage. However, it is less suitable (probably due to high terrain heterogeneity) for mapping in areas with luvisol as dominant soil unit. Acknowledgement: This study was supported by NAZV Agency of the Ministry of Agriculture of the Czech Republic through grant No QJ1230319. References : Royall, D. (2001). Use of mineral magnetic measurements to investigate soil erosion and sediment delivery in small agricultural catchment in limestone terrain. Catena, 46, 15-34. Kapicka, A., Dlouha, S., Grison, H., Jaksik, O., Kodesova, R., Petrovsky, E. (2013) Magnetism of soils applied for estimation of erosion at an agricultural land. Geophys Res Abstr Vol. 15, EGU2013 -4774.

Surface pavement solutions for poor subgrade conditions phase II : performance analysis of test sections and implementation guidelines : summary.

DOT National Transportation Integrated Search

2010-12-01

Several areas within FDOT Districts 4 and 6 contain thick layers of organic soils at relatively shallow depths. Roads built on these soft compressible soils : often develop premature cracking, distortion, and settlement. Traditional repair methods, s...

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

NASA Astrophysics Data System (ADS)

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

2018-01-01

Slope is a part of soil topography formed due to elevation difference from two soil surface. Landslides is frequently occur in natural slope, it is because shear force is greater than shear strength in the soil. There are some factor that influence slope stability such as: rain dissipation, vibration from earthquake, construction and crack in the soil. Slope instability can cause risk in human activity or even threaten human lives. Every years in rainy season, landslides always occur in Indonesia. In 2016, there was some landslide occurred in Bali. One of the most damaging is landslide in Petang district, Badung regency. This landslide caused main road closed entirely. In order to overcome and prevent landslide, a lot of method have been practiced and still looking for more sophisticated method for forecasting slope stability. One of the method to strengthen soil stability is filling the soil pores with some certain material. Cement is one of the material that can be used to fill the soil pores because when it is in liquid form, it can infiltrate into soil pores and fill the gap between soil particles. And after it dry, it can formed a bond with soil particle so that soil become stronger and the slope as well. In this study, it will use experimental method, slope model in laboratory to simulate a real slope behavior in the field. The first model is the slope without any addition of cement. This model will be become a benchmark for the other models. The second model is a slope with improved soil that injects the slope with cement. Injection of cement is done with varying interval distance of injection point is 5 cm and 10 cm. Each slope model will be given a load until the slope collapses. The slope model will also be analyzed with slope stability program. The test results on the improved slope models will be compared with unimproved slope. In the initial test will consist of 3 model. First model is soil without improvement or cement injection, second model is soil with cement injection interval 5 cm and third model is soil with cement injection interval 10 cm. The result is the shear strength (ϕ value) the soil is increase from 32.02° to 47.57°. The increase value of internal friction angle (ϕ) shows that an increase in shear strength of the cement improved soil. While, the value of cohesion (c) is zero indicating there is no cohesion in the soil. This is common for sand soil or sandy soil. The calculation of safety factor with GeoStructural Analysis obtained an increase of safety factor from 0.78 if the soil without cement injection to 1.07 and 1.17 if the soil is injected with cement at a distance of 10 cm and 5 cm.

Development of fast and robust multiresidual LC-MS/MS method for determination of pharmaceuticals in soils.

PubMed

Golovko, Oksana; Koba, Olga; Kodesova, Radka; Fedorova, Ganna; Kumar, Vimal; Grabic, Roman

2016-07-01

The aim of this study was to develop a simple extraction procedure and a multiresidual liquid chromatography-tandem mass spectrometry method for determination of a wide range of pharmaceuticals from various soil types. An extraction procedure for 91 pharmaceuticals from 13 soil types, followed by liquid chromatography-tandem mass spectrometry analysis, was optimized. The extraction efficiencies of three solvent mixtures for ultrasonic extraction were evaluated for 91 pharmaceuticals. The best results were obtained using acetonitrile/water (1/1 v/v with 0.1 % formic acid) followed by acetonitrile/2-propanol/water (3/3/4 v/v/v with 0.1 % formic acid) for extracting 63 pharmaceuticals. The method was validated at three fortification levels (10, 100, and 1000 ng/g) in all types of representative soils; recovery of 44 pharmaceuticals ranged between 55 and 135 % across all tested soils. The method was applied to analyze actual environmental samples of sediments, soils, and sludge, and 24 pharmaceuticals were found above limit of quantification with concentrations ranging between 0.83 ng/g (fexofenadine) and 223 ng/g (citalopram).

Comparison of in situ DGT measurement with ex situ methods for predicting cadmium bioavailability in soils with combined pollution to biotas.

PubMed

Wang, Peifang; Liu, Cui; Yao, Yu; Wang, Chao; Wang, Teng; Yuan, Ye; Hou, Jun

2017-05-01

To assess the capabilities of the different techniques in predicting Cadmium (Cd) bioavailability in Cd-contaminated soils with the addition of Zn, one in situ technique (diffusive gradients in thin films; DGT) was compared with soil solution concentration and four widely used single-step extraction methods (acetic acid, EDTA, sodium acetate and CaCl 2 ). Wheat and maize were selected as tested species. The results demonstrated that single Cd-polluted soils inhibited the growth of wheat and maize significantly compared with control plants; the shoot and root biomasses of the plants both dropped significantly (P < 0.05). The addition of Zn exhibited a strong antagonism to the physiological toxicity induced by Cd. The Pearson correlation coefficient presented positive correlations (P < 0.01, R > 0.9) between Cd concentrations in two plants and Cd bioavailability indicated by each method in soils. Consequently, the results indicated that the DGT technique could be regarded as a good predictor of Cd bioavailability to plants, comparable to soil solution concentration and the four single-step extraction methods. Because the DGT technique can offer in situ data, it is expected to be widely used in more areas.

Acute toxicity assessment of explosive-contaminated soil extracting solution by luminescent bacteria assays.

PubMed

Xu, Wenjie; Jiang, Zhenming; Zhao, Quanlin; Zhang, Zhenzhong; Su, Hongping; Gao, Xuewen; Ye, Zhengfang

2016-11-01

Explosive-contaminated soil is harmful to people's health and the local ecosystem. The acute toxicity of its extracting solution was tested by bacterial luminescence assay using three kinds of luminescent bacteria to characterize the toxicity of the soil. An orthogonal test L 16 (4 5 ) was designed to optimize the soil extracting conditions. The optimum extracting conditions were obtained when the ultrasonic extraction time, ultrasonic extraction temperature, and the extraction repeat times were 6 h, 40 °C, and three, respectively. Fourier transform infrared spectroscopy (FTIR) results showed that the main components of the contaminated soil's extracting solution were 2,4-dinitrotoluene-3-sulfonate (2,4-DNT-3-SO 3 - ); 2,4-dinitrotoluene-5-sulfonate (2,4-DNT-5-SO 3 - ); and 2,6-dinitrotoluene (2,6-DNT). Compared with Photobacterium phosphoreum and Vibrio fischeri, Vibrio qinghaiensis sp. Nov. is more suitable for assessing the soil extracting solution's acute toxicity. Soil washing can remove most of the contaminants toxic to luminescent bacterium Vibrio qinghaiensis sp. Nov., suggesting that it may be a potential effective remediation method for explosive-contaminated soil.

Sorption and degradation of wastewater-associated pharmaceuticals and personal care products in agricultural soils and sediment.

PubMed

Zhang, Ting; Wu, Bo; Sun, Na; Ye, Yong; Chen, Huaixia

2013-01-01

Pharmaceuticals and personal care products (PPCPs) have drawn popular concerns recently as an emerging class of aquatic contaminants. In this study, adsorption and degradation of four selected PPCPs, metronidazole, tinidazole, caffeine and chloramphenicol, have been investigated in the laboratory using two agricultural soils in China and sediment from Changjiang River. Adsorption tests using a batch equilibrium method demonstrated that adsorption of all tested chemicals in soils could be well described with Freundlich equation, and their adsorption affinity on soil followed the order of chloramphenicol > caffeine > tinidazole > metronidazole. Generally, higher Kf value was associated with soils which had higher organic matter contents (except for caffeine acid in this study). Degradation of selected PPCPs in soils generally followed first-order exponential decay kinetics, and half-lives ranging from 0.97 to 10.21 d. Sterilization generally decreased the degradation rates, indicating that microbial activity played a significant role in the degradation in soils. The degradation rate constant decreased with increasing initial chemical concentrations in soil, implying that the microbial activity was inhibited with high chemical loading levels.

The instrumental method of plutonium determination

NASA Astrophysics Data System (ADS)

Knyazev, B. B.; Kazachevskiy, I. V.; Solodukhin, V. P.; Lukashenko, S. N.; Knatova, M. K.; Kashirskiy, V. V.

2003-01-01

A method of direct instrumental determination of plutonium isotopes in soil samples is described. For the method a special program of spectra processing and activity calculation had to be prepared. The detection limit of 239+240Pu in absence of interfering radiation is about 200 Bq/kg (by 3.3σ criteria). Examples are given of the method application for the study of radionuclide soil composition in separate objects of Semipalatinsk Nuclear Test Site (SNTS). It is shown that for different objects under study the correlation degree between plutonium and americium activities may change rather substantially.

Recent studies of measures to improve basamid soil disinfestation.

PubMed

Van Wambeke, E

2011-01-01

Basamid micro-granule is used worldwide as a broad spectrum soil fumigant generator and has replaced methyl bromide for many applications. A lot is known for decades regarding the factors determining the success of the application from soil preparation and conditions to the application and soil sealing or soil tarping, as well as the operations and hygienic measures after the fumigant contact time. This paper explains last 6 years studies regarding the improvement of application methods, both from the viewpoint of homogenous incorporation of the granule over the soil profile to become treated as well as from possible premature loss of the gaseous active methyl isothiocyanate (MITC) by using improved tarping materials. Both result in lower environmental exposure and better biological performance of the application. In that respect, product incorporation in soil was studied in France and in Italy with more recent commercially available Basamid application machinery, and 29 plastic films have been compared for their MITC barrier properties with an 'in house' developed method. Film testing allowed clear categorizing in standard (monolayer) films, V.I.F. (Virtually Impermeable Film) and T.I.F. (Totally Impermeable Film). The paper presents the methodology for granule incorporation study and results from trials with two specific Basamid application machines compared with a classic rotovator, the methodology and comparison of plastic film barrier properties testing, and directives to minimize exposure and to maximize performance.

Evaluation of Mobility, Bioavailability and Toxicity of Pb and Cd in Contaminated Soil Using TCLP, BCR and Earthworms

PubMed Central

Kede, Maria Luiza F. M.; Correia, Fabio V.; Conceição, Paulo F.; Salles Junior, Sidney F.; Marques, Marcia; Moreira, Josino C.; Pérez, Daniel V.

2014-01-01

The objective of the present study was to investigate the reduction of mobility, availability and toxicity found in soil contaminated with lead (Pb) and cadmium (Cd) from Santo Amaro Municipality, Bahia, Brazil using two combined methods, commonly tested separately according to the literature: metal mobilization with phosphates and phytoextraction. The strategy applied was the treatment with two sources of phosphates (separately and mixed) followed by phytoremediation with vetiver grass (Vetiveria zizanioides (L.)). The treatments applied (in triplicates) were: T1—potassium dihydrogen phosphate (KH2PO4); T2—reactive natural phosphate fertilizer (NRP) and; T3—a mixture 1:1 of KH2PO4 and NRP. After this step, untreated and treated soils were planted with vetiver grass. The extraction procedures and assays applied to contaminated soil before and after the treatments included metal mobility test (TCLP); sequential extraction with BCR method; toxicity assays with Eisenia andrei. The soil-to-plant transfer factors (TF) for Pb and Cd were estimated in all cases. All treatments with phosphates followed by phytoremediation reduced the mobility and availability of Pb and Cd, being KH2PO4 (T1) plus phytoremediation the most effective one. Soil toxicity however, remained high after all treatments. PMID:25386955

An in situ method for real-time monitoring of soil gas diffusivity

NASA Astrophysics Data System (ADS)

Laemmel, Thomas; Maier, Martin; Schack-Kirchner, Helmer; Lang, Friederike

2016-04-01

Soil aeration is an important factor for the biogeochemistry of soils. Generally, gas exchange between soil and atmosphere is assumed to be governed by molecular diffusion and by this way fluxes can be calculated using by Fick's Law. The soil gas diffusion coefficient DS represents the proportional factor between the gas flux and the gas concentration gradient in the soil and reflects the ability of the soil to "transport passively" gas through the soil. One common way to determine DS is taking core samples in the field and measuring DS in the lab. Unfortunately this method is destructive and laborious and it can only reflect a small fraction of the whole soil. As a consequence, uncertainty about the resulting effective diffusivity on the profile scale, i.e. the real aeration status remains. We developed a method to measure and monitor DS in situ. The set-up consists of a custom made gas sampling device, the continuous injection of an inert tracer gas and inverse gas transport modelling in the soil. The gas sampling device has seven sampling depths (from 0 to -43 cm of depth) and can be easily installed into vertical holes drilled by an auger, which allows for fast installation of the system. Helium (He) as inert tracer gas was injected continuously at the lower end of the device. The resulting steady state distribution of He was used to deduce the DS depth distribution of the soil. For Finite Element Modeling of the gas-sampling-device/soil system the program COMSOL was used. We tested our new method both in the lab and in a field study and compared the results with a reference lab method using soil cores. DS profiles obtained by our in-situ method were consistent with DS profiles determined based on soil core analyses. Soil gas profiles could be measured with a temporal resolution of 30 minutes. During the field study, there was an important rain event and we could monitor the decrease in soil gas diffusivity in the top soil due to water infiltration. The effect of soil water infiltration deeper into the soil on soil gas diffusivity could be observed during the following hours. Our new DS determination device can be quickly and easily installed and allows for monitoring continuously soil gas transport over a long time. It allows following modifications of soil gas diffusivity due to rain events. In addition it enables the analysis of non-diffusive soil gas transport processes.

A Biochar Classification System and Associated Test Methods

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

Camps-Arbestain, Marta; Amonette, James E.; Singh, Balwant

2015-02-18

In this chapter, a biochar classification system related to its use as soil amendment is proposed. This document builds upon previous work and constrains its scope to materials with properties that satisfy the criteria for biochar as defined by either the International Biochar Initiative (IBI) Biochar Standards or the European Biochar Community (EBC) Standards, and it is intended to minimise the need for testing in addition to those required according to the above-mentioned standards. The classification system envisions enabling stakeholders and commercial entities to (i) identify the most suitable biochar to fulfil the requirements for a particular soil and/or land-use,more » and (ii) distinguish the application of biochar for specific niches (e.g., soilless agriculture). It is based on the best current knowledge and the intention is to periodically review and update the document based on new data and knowledge that become available in the scientific literature. The main thrust of this classification system is based on the direct or indirect beneficial effects that biochar provides from its application to soil. We have classified the potential beneficial effects of biochar application to soils into five categories with their corresponding classes, where applicable: (i) carbon (C) storage value, (ii) fertiliser value, (iii) liming value, (iv) particle-size, and (v) use in soil-less agriculture. A summary of recommended test methods is provided at the end of the chapter.« less

Intercomparison of Lab-Based Soil Water Extraction Methods for Stable Water Isotope Analysis

NASA Astrophysics Data System (ADS)

Pratt, D.; Orlowski, N.; McDonnell, J.

2016-12-01

The effect of pore water extraction technique on resultant isotopic signature is poorly understood. Here we present results of an intercomparison of five common lab-based soil water extraction techniques: high pressure mechanical squeezing, centrifugation, direct vapor equilibration, microwave extraction, and cryogenic extraction. We applied five extraction methods to two physicochemically different standard soil types (silty sand and clayey loam) that were oven-dried and rewetted with water of known isotopic composition at three different gravimetric water contents (8, 20, and 30%). We tested the null hypothisis that all extraction techniques would provide the same isotopic result independent from soil type and water content. Our results showed that the extraction technique had a significant effect on the soil water isotopic composition. Each method exhibited deviations from spiked reference water, with soil type and water content showing a secondary effect. Cryogenic extraction showed the largest deviations from the reference water, whereas mechanical squeezing and centrifugation provided the closest match to the reference water for both soil types. We also compared results for each extraction technique that produced liquid water on both an OA-ICOS and IRMS; differences between them were negligible.

Lead (II) removal from natural soils by enhanced electrokinetic remediation.

PubMed

Altin, Ahmet; Degirmenci, Mustafa

2005-01-20

Electrokinetic remediation is a very effective method to remove metal from fine-grained soils having low adsorption and buffering capacity. However, remediation of soil having high alkali and adsorption capacity via the electrokinetic method is a very difficult process. Therefore, enhancement techniques are required for use in these soil types. In this study, the effect of the presence of minerals having high alkali and cation exchange capacity in natural soil polluted with lead (II) was investigated by means of the efficiency of electrokinetic remediation method. Natural soil samples containing clinoptilolite, gypsum and calcite minerals were used in experimental studies. Moreover, a sample containing kaolinite minerals was studied to compare with the results obtained from other samples. Best results for soils bearing alkali and high sorption capacity minerals were obtained upon addition of 3 mol AcH and application of 20 V constant potential after a remediation period of 220 h. In these test conditions, lead (II) removal efficiencies for these samples varied between 60% and 70% up to 0.55 normalized distance. Under the same conditions, removal efficiencies in kaolinite sample varied between 50% and 95% up to 0.9 normalized distance.

Assessing SOC labile fractions through respiration test, density-size fractionation and thermal analysis - A comparison of methods

NASA Astrophysics Data System (ADS)

Soucemarianadin, Laure; Cécillon, Lauric; Chenu, Claire; Baudin, François; Nicolas, Manuel; Savignac, Florence; Barré, Pierre

2017-04-01

Soil organic matter (SOM) is the biggest terrestrial carbon reservoir, storing 3 to 4 times more carbon than the atmosphere. However, despite its major importance for climate regulation SOM dynamics remains insufficiently understood. For instance, there is still no widely accepted method to assess SOM lability. Soil respiration tests and particulate organic matter (POM) obtained by different fractionation schemes have been used for decades and are now considered as classical estimates of very labile and labile soil organic carbon (SOC), respectively. But the pertinence of these methods to characterize SOM turnover can be questioned. Moreover, they are very time-consuming and their reproducibility might be an issue. Alternate ways of determining the labile SOC component are thus well-needed. Thermal analyses have been used to characterize SOM among which Rock-Eval 6 (RE6) analysis of soil has shown promising results in the determination of SOM biogeochemical stability (Gregorich et al., 2015; Barré et al., 2016). Using a large set of samples of French forest soils representing contrasted pedoclimatic conditions, including deep samples (up to 1 m depth), we compared different techniques used for SOM lability assessment. We explored whether results from soil respiration test (10-week laboratory incubations), SOM size-density fractionation and RE6 thermal analysis were comparable and how they were correlated. A set of 222 (respiration test and RE6), 103 (SOM fractionation and RE6) and 93 (respiration test, SOM fractionation and RE6) forest soils samples were respectively analyzed and compared. The comparison of the three methods (n = 93) using a principal component analysis separated samples from the surface (0-10 cm) and deep (40-80 cm) layers, highlighting a clear effect of depth on the short-term persistence of SOC. A correlation analysis demonstrated that, for these samples, the two classical methods of labile SOC determination (respiration and SOM fractionation) were only weakly positively correlated (Spearman's ρ = 0.26, n = 93). Similarly, soil respiration had only a weak negative correlation (Spearman's ρ = -0.24, n = 93; ρ = -0.33, n = 222) with the RE6 parameter T50 CH pyrolysis. This parameter, previously used as an indicator of labile SOC (Gregorich et al., 2015), represents the temperature at which 50% of the OM was pyrolyzed to effluents (mainly hydrocarbons) during the pyrolysis phase of RE6. Conversely, POC content (% of total SOC) showed a higher negative correlation with T50 CH pyrolysis (ρ = -0.66, n = 93; ρ = -0.65, n = 103) and was positively and negatively correlated to the hydrogen index, HI (mg HC/g TOC; ρ = 0.56/0.53) and the oxygen index, OI (mg CO2/g TOC; ρ = -0.63/-0.62) respectively. Our results showed that RE6 results are consistent with respiration and fractionation results: SOC with higher respiration rate and higher POC content burns at a lower temperature. RE6 thermal analysis could therefore be viewed as a useful fast and cost effective alternative to more time-consuming methods used in SOM fractions determination. Barré, P. et al. Biogeochemistry 2016, 1-12, 130. Gregorich, E.G. et al. Soil Biol. Biochem. 2015, 182-191, 91.

Application of Magnetic and Geotechnical Methods for Archaeological Site Investigations

DTIC Science & Technology

2011-07-01

national historic preservation act NRM natural remnant magnetism NS north-south nT nano Tesla ID inside diameter OSB oriented strand board psi...3.4 Soil Box Experiments Compaction tests were conducted by loading soil into a wooden box (1 m3) constructed of oriented strand board ( OSB ) and

Developing VTM-51 into an ASTM test method.

DOT National Transportation Integrated Search

1993-01-01

In 1980, the Virginia Transportation Research Council developed a procedure to test silt fence installations (VTM-51). The test determines the filtering efficiency (amount of soil removed) and the flow rate of a geotextile. A known concentration and ...

Calibrating Nonlinear Soil Material Properties for Seismic Analysis Using Soil Material Properties Intended for Linear Analysis

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

Spears, Robert Edward; Coleman, Justin Leigh

2015-08-01

Seismic analysis of nuclear structures is routinely performed using guidance provided in “Seismic Analysis of Safety-Related Nuclear Structures and Commentary (ASCE 4, 1998).” This document, which is currently under revision, provides detailed guidance on linear seismic soil-structure-interaction (SSI) analysis of nuclear structures. To accommodate the linear analysis, soil material properties are typically developed as shear modulus and damping ratio versus cyclic shear strain amplitude. A new Appendix in ASCE 4-2014 (draft) is being added to provide guidance for nonlinear time domain SSI analysis. To accommodate the nonlinear analysis, a more appropriate form of the soil material properties includes shear stressmore » and energy absorbed per cycle versus shear strain. Ideally, nonlinear soil model material properties would be established with soil testing appropriate for the nonlinear constitutive model being used. However, much of the soil testing done for SSI analysis is performed for use with linear analysis techniques. Consequently, a method is described in this paper that uses soil test data intended for linear analysis to develop nonlinear soil material properties. To produce nonlinear material properties that are equivalent to the linear material properties, the linear and nonlinear model hysteresis loops are considered. For equivalent material properties, the shear stress at peak shear strain and energy absorbed per cycle should match when comparing the linear and nonlinear model hysteresis loops. Consequently, nonlinear material properties are selected based on these criteria.« less

Filter Membrane Effects on Water-Extractable Phosphorus Concentrations from Soil.

PubMed

Norby, Jessica; Strawn, Daniel; Brooks, Erin

2018-03-01

To accurately assess P concentrations in soil extracts, standard laboratory practices for monitoring P concentrations are needed. Water-extractable P is a common analytical test to determine P availability for leaching from soils, and it is used to determine best management practices. Most P analytical tests require filtration through a filter membrane with 0.45-μm pore size to distinguish between particulate and dissolved P species. However, filter membrane type is rarely specified in method protocols, and many different types of membranes are available. In this study, three common filter membrane materials (polyether sulfone, nylon, and nitrocellulose), all with 0.45-μm pore sizes, were tested for analytical differences in total P concentrations and dissolved reactive P (DRP) concentrations in water extracts from six soils sampled from two regions. Three of the extracts from the six soil samples had different total P concentrations for all three membrane types. The other three soil extracts had significantly different total P results from at least one filter membrane type. Total P concentration differences were as great as 35%. The DRP concentrations in the extracts were dependent on filter type in five of the six soil types. Results from this research show that filter membrane type is an important parameter that affects concentrations of total P and DRP from soil extracts. Thus, membrane type should be specified in soil extraction protocols. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Soil heating and evaporation under extreme conditions: Forest fires and slash pile burns

NASA Astrophysics Data System (ADS)

Massman, W. J.

2011-12-01

Heating any soil during a sufficiently intense wild fire or prescribed burn can alter soil irreversibly, resulting in many significant and well known, long term biological, chemical, and hydrological effects. To better understand how fire impacts soil, especially considering the increasing probability of wildfires that is being driven by climate change and the increasing use of prescribe burns by land managers, it is important to better understand the dynamics of the coupled heat and moisture transport in soil during these extreme heating events. Furthermore, improving understanding of heat and mass transport during such extreme conditions should also provide insights into the associated transport mechanisms under more normal conditions as well. Here I describe the development of a new model designed to simulate soil heat and moisture transport during fires where the surface heating often ranges between 10,000 and 100,000 Wm-2 for several minutes to several hours. Model performance is tested against laboratory measurements of soil temperature and moisture changes at several depths during controlled heating events created with an extremely intense radiant heater. The laboratory tests employed well described soils with well known physical properties. The model, on the other hand, is somewhat unusual in that it employs formulations for temperature dependencies of the soil specific heat, thermal conductivity, and the water retention curve (relation between soil moisture and soil moisture potential). It also employs a new formulation for the surface evaporation rate as a component of the upper boundary condition, as well as the Newton-Raphson method and the generalized Thomas algorithm for inverting block tri-diagonal matrices to solve for soil temperature and soil moisture potential. Model results show rapid evaporation rates with significant vapor transfer not only to the free atmosphere above the soil, but to lower depths of the soil, where the vapor re-condenses ahead of the heating front. Consequently the trajectory of the solution (soil volumetric water content versus soil temperature) is very unusual and highly nonlinear, which may explain why more traditional methods (i.e., those based on finite difference or finite element approaches) tend to show more numerical instabilities than the Newton-Raphson method when used to model these extreme conditions. But, despite the intuitive and qualitative appeal of the model's numerical solution, it underestimates the rate of soil moisture loss observed during the laboratory trials, although the soil temperatures are reasonably well simulated.

40 CFR 258.41 - Project XL Bioreactor Landfill Projects.

Code of Federal Regulations, 2012 CFR

2012-07-01

... using the Standard Test Method for Measuring Mass per Unit Area of Geotextiles, ASTM D-5261-92... determined by the Standard Test Method for Laboratory Determination of Water (Moisture) Content of Soil and... with the provisions of the FESOP, during the entire period of leachate recirculation and the post...

40 CFR 258.41 - Project XL Bioreactor Landfill Projects.

Code of Federal Regulations, 2011 CFR

2011-07-01

... using the Standard Test Method for Measuring Mass per Unit Area of Geotextiles, ASTM D-5261-92... determined by the Standard Test Method for Laboratory Determination of Water (Moisture) Content of Soil and... with the provisions of the FESOP, during the entire period of leachate recirculation and the post...

40 CFR 258.41 - Project XL Bioreactor Landfill Projects.

Code of Federal Regulations, 2013 CFR

2013-07-01

... using the Standard Test Method for Measuring Mass per Unit Area of Geotextiles, ASTM D-5261-92... determined by the Standard Test Method for Laboratory Determination of Water (Moisture) Content of Soil and... with the provisions of the FESOP, during the entire period of leachate recirculation and the post...

Rapid in situ assessment for predicting soil quality using an algae-soaked disc seeding assay.

PubMed

Nam, Sun-Hwa; Moon, Jongmin; Kim, Shin Woong; Kim, Hakyeong; Jeong, Seung-Woo; An, Youn-Joo

2017-11-16

The soil quality of remediated land is altered and this land consequently exerts unexpected biological effects on terrestrial organisms. Therefore, field evaluation of such land should be conducted using biological indicators. Algae are a promising new biological indicator since they are a food source for organisms in higher soil trophic levels and easily sampled from the soil. Field evaluation of soil characteristics is preferred to be testing in laboratory conditions because many biological effects cannot be duplicated during laboratory evaluations. Herein, we describe a convenient and rapid algae-soaked disc seeding assay for assessing soil quality in the field based on soil algae. The collection of algae is easy and rapid and the method predicts the short-term quality of contaminated, remediated, and amended farm and paddy soils. The algae-soaked disc seeding assay is yet to be extensively evaluated, and the method cannot be applied to loamy sand soil in in situ evaluations. The algae-soaked disc seeding assay is recommended for prediction of soil quality in in situ evaluations because it reflects all variations in the environment. The algae-soaked disc seeding assay will help to develop management strategies for in situ evaluation.

Field measurements of the linear and nonlinear shear moduli of cemented alluvium using dynamically loaded surface footings

NASA Astrophysics Data System (ADS)

Park, Kwangsoo

In this dissertation, a research effort aimed at development and implementation of a direct field test method to evaluate the linear and nonlinear shear modulus of soil is presented. The field method utilizes a surface footing that is dynamically loaded horizontally. The test procedure involves applying static and dynamic loads to the surface footing and measuring the soil response beneath the loaded area using embedded geophones. A wide range in dynamic loads under a constant static load permits measurements of linear and nonlinear shear wave propagation from which shear moduli and associated shearing strains are evaluated. Shear wave velocities in the linear and nonlinear strain ranges are calculated from time delays in waveforms monitored by geophone pairs. Shear moduli are then obtained using the shear wave velocities and the mass density of a soil. Shear strains are determined using particle displacements calculated from particle velocities measured at the geophones by assuming a linear variation between geophone pairs. The field test method was validated by conducting an initial field experiment at sandy site in Austin, Texas. Then, field experiments were performed on cemented alluvium, a complex, hard-to-sample material. Three separate locations at Yucca Mountain, Nevada were tested. The tests successfully measured: (1) the effect of confining pressure on shear and compression moduli in the linear strain range and (2) the effect of strain on shear moduli at various states of stress in the field. The field measurements were first compared with empirical relationships for uncemented gravel. This comparison showed that the alluvium was clearly cemented. The field measurements were then compared to other independent measurements including laboratory resonant column tests and field seismic tests using the spectral-analysis-of-surface-waves method. The results from the field tests were generally in good agreement with the other independent test results, indicating that the proposed method has the ability to directly evaluate complex material like cemented alluvium in the field.

Participatory innovation process for testing new practices for soil fertility management in Chókwè Irrigation Scheme (Mozambique)

NASA Astrophysics Data System (ADS)

Sánchez Reparaz, Maite; de Vente, Joris; Famba, Sebastiao; Rougier, Jean-Emmanuel; Ángel Sánchez-Monedero, Miguel; Barberá, Gonzalo G.

2015-04-01

Integrated water and nutrient management are key factors to increase productivity and to reduce the yield gap in irrigated systems in Sub-Saharan Africa. These two elements are affected by an ensemble of abiotic, biotic, management and socio-economic factors that need to be taken into account to reduce the yield gap, as well as farmers' perceptions and knowledge. In the framework of the project European Union and African Union cooperative research to increase Food production in irrigated farming systems in Africa (EAU4Food project) we are carrying out a participatory innovation process in Chókwè irrigation scheme (Mozambique) based on stakeholders engagement, to test new practices for soil fertility management that can increase yields reducing costs. Through a method combining interviews with three farmers' associations and other relevant stakeholders and soil sampling from the interviewed farmers' plots with the organization of Communities of Practices, we tried to capture how soil fertility is managed by farmers, the constraints they find as well as their perceptions about soil resources. This information was the basis to design and conduct a participatory innovation process where compost made with rice straw and manure is being tested by a farmers' association. Most important limitations of the method are also evaluated. Our results show that socio-economic characteristics of farmers condition how they manage soil fertility and their perceptions. The difficulties they face to adopt new practices for soil fertility management, mainly related to economic resources limitations, labour availability, knowledge time or farm structure, require a systemic understanding that takes into account abiotic, biotic, management and socio-economic factors and their implication as active stakeholders in all phases of the innovation process.

In-Situ Quantification of Microbial Processes Controlling Methane Emissions From Rice Plants

NASA Astrophysics Data System (ADS)

Schroth, M. H.; Cho, R.; Zeyer, J. A.

2011-12-01

Methane is an important greenhouse gas contributing to global warming. Among other sources, rice (paddy) soils represent a major nonpoint source of biogenic methane. In flooded paddy soils methane is produced under anaerobic conditions. Conversely, methanotrophic microorganisms oxidize methane to carbon dioxide in the root zone of rice plants, thus reducing overall methane emissions to the atmosphere. We present a novel combination of methods to quantify methanogenesis and methane oxidation in paddy soils and to link methane turnover to net emissions of rice plants. To quantify methane turnover in the presence of high methane background concentrations, small-scale push-pull tests (PPTs) were conducted in paddy soils using stable isotope-labeled substrates. Deuterated acetate and 13-C bicarbonate were employed to discern and quantify acetoclastic and hydrogenotrophic methanogenesis, while 13-C methane was employed to quantify methane oxidation. During 2.5 hr-long PPTs, 140 mL of a test solution containing labeled substrates and nonreactive tracers (Ar, Br-) was injected into paddy soils of potted rice plants. After a short rest period, 480 mL of test solution/pore water mixture was extracted from the same location. Methane turnover was then computed from extraction-phase breakthrough curves of substrates and/or products, and nonreactive tracers. To link methane turnover to net emissions, methane emissions from paddy soils and rice plants were individually determined immediately preceding PPTs using static flux chambers. We will present results of a series of experiments conducted in four different potted rice plants. Preliminary results indicate substantial variability in methane turnover and net emission between different rice plants. The employed combination of methods appears to provide a robust means to quantitatively link methane turnover in paddy soils to net emissions from rice plants.

Bioindication of human-induced soil degradation in enclosed karst depressions (dolines) using Ellenberg indicator values (Classical Karst, Slovenia).

PubMed

Breg Valjavec, Mateja; Zorn, Matija; Čarni, Andraž

2018-05-29

One of the frequently used bioindication methods is Ellenberg indicator values (EIVs), which are commonly applied in Central Europe as bioindicators of ecological characteristics. However, very few studies have tested EIVs as a bioindication of human-induced soil degradation. We tested the ability of EIVs to distinguish between localities of degraded karst depressions (dolines) and localities of semi-natural (agricultural) soils in preserved dolines on the Kras Plateau (Classical Karst, SW Slovenia). We compared the results of bioindications of soil nutrient content (N), soil reaction (R) and soil moisture (M) with measured soil parameters. Low values of organic carbon, a slightly alkaline soil reaction and low organic sulphur content are chemical indicators of soil degradation in dolines, in comparison with preserved reference dolines (high organic carbon, slightly acid reaction, higher S). EIV reaction is the most reliable plant indicator value that can distinguish between degraded and non-degraded soil plots. According to a regression tree, sulphur (S) and C/N are the most important factors for division on the basis of EIV reaction. By applying the EIV reaction of diagnostic plant species, we significantly improved bioindication of soil degradation, although in the case of EIV nutrients, bioindication was not improved. Copyright © 2018. Published by Elsevier B.V.

Aided Phytostabilization of Copper Contaminated Soils with L. Perenne and Mineral Sorbents as Soil Amendments

NASA Astrophysics Data System (ADS)

Radziemska, Maja

2017-09-01

The present study was designed to assess phytostabilization strategies for the treatment of soil co-contaminated by increasing levels of copper with the application mineral amendments (chalcedonite, zeolite, dolomite). From the results it will be possible to further elucidate the benefits or potential risks derived from the application of different types of mineral amendments in the remediation of a copper contaminated soil. A glasshouse pot experiment was designed to evaluate the potential use of different amendments as immobilizing agents in the aided phytostabilization of Cu-contaminated soil using ryegrass (Lolium perenne L.). The content of trace elements in plants and total in soil, were determined using the method of spectrophotometry. All of the investigated element contents in the tested parts of L. perenne were significantly different in the case of applying mineral amendments to the soil, as well as increasing concentrations of copper. The greatest average above-ground biomass was observed for soil amended with chalcedonite. In this experiment, all analyzed metals accumulated predominantly in the roots of the tested plant. In general, applying mineral amendments to soil contributed to decreased levels of copper concentrations.

GPR monitoring for non-uniform infiltration through a high permeable gravel layer in the test sand box

NASA Astrophysics Data System (ADS)

Kuroda, Seiichiro; Ishii, Nobuyuki; Morii, Toshihiro

2017-04-01

Recently capillary barriers have been known as a method to protect subsurface regions against infiltration from soil surface. It has essentially non-uniform structure of permeability or soil physical property. To identify the function of the capillary barrier, the site-characterization technique for non-uniform soil moisture distribution and infiltration process is needed. We built a sand box in which a thin high-permeable gravel layer was embedded and conducted a infiltration test, including non-uniform flow of soil water induced by capillary barrier effects. We monitored this process by various types of GPR measurements, including time-lapsed soundings with multi-frequency antenna and transmission measurements like one using cross-borehole radar. Finally we will discuss the applicability of GPR for monitoring the phenomena around the capillary barrier of soil. This work has partially supported by JSPS Grant-in-aid Scientific Research program, No.16H02580.

The use of soil quality indicators to assess soil functionality in restored semi-arid ecosystems

NASA Astrophysics Data System (ADS)

Muñoz-Rojas, Miriam; Erickson, Todd E.; Dixon, Kingsley W.; Merritt, David J.

2016-04-01

Keywords: Pilbara, 1-day CO2 test, microbial activity, mine restoration, soil health, ecosystem services. Introduction Semi-arid and arid environments are highly vulnerable to land degradation and their restoration has commonly showed low rates of success (James et al., 2013). A systematic knowledge of soil functionality is critical to successful restoration of degraded ecosystems since approximately 80% of ecosystem services can be connected to soil functions. The assessment of soil functionality generally involves the evaluation of soil properties and processes as they relate to the ability of soil to function effectively as a component of a healthy ecosystem (Costantini et al., 2015) Using soil quality indicators may be a valuable approach to assess functionality of topsoil and novel substrates used in restoration (Muñoz-Rojas et al., 2014; 2015). A key soil chemical indicator is soil organic C, that has been widely used as an attribute of soil quality because of the many functions that it provides and supports (Willaarts et al., 2015). However, microbial indicators can be more sensitive to disturbances and could be a valuable addition in soil assessment studies in restoration programs. Here, we propose a set of soil quality indicators to assess the soil status in restored soils (topsoil and waste material) of semi-arid environments. The study was conducted during March 2015 in the Pilbara biogeographical region (northwestern Australia) at an iron ore mine site rehabilitated in 2011. Methods Soil samples were collected from two sub-areas with different soil materials used as growth media: topsoil retrieved from nearby stockpiles and a lateritic waste material utilised for its erosive stability and physical competence. An undisturbed natural shrub-grassland ecosystem dominated by Triodia spp. and Acacia spp. representative of the restored area was selected as the analogue reference site. Soil physicochemical analysis were undertaken according to standard methods. Soil microbial activity was measured with the 1-day CO2 test, a cost-effective and rapid method to determine soil microbial respiration rate based on the measurement of the CO2 burst produced after moistening dry soil (Muñoz-Rojas et al., 2016). Soil microbial abundance of specific groups was measured by phospholipid fatty acid analysis. Results and discussion We showed that in addition to organic C and C:N ratio, biological indicators (microbial diversity and activity in particular), are the most sensitive indicators to detect differences among reconstructed soils and analogue undisturbed soils in semi-arid areas. The 1-day CO2 test is an alternative cost- and time-effective method to measure microbial activity and assess soil functionality of restored soils. Our results also showed a positive effect of vegetation on reconstructed soils and a recovery of soil functionality in waste material to levels similar to topsoil once vegetation is established, although soil quality levels are still far from those in undisturbed native soils four years post-restoration. Soil functionality is critical in the restoration process, particularly in semi-arid areas, and the methods used here could be effectively applied in a broad range of restoration projects in arid and semi-arid environments. References Costantini EAC, Branquinho C, Nunes A, Schwilch G, Stavi I, Valdecantos A and Zucca C (2015) Soil indicators to assess the effectiveness of restoration strategies in dryland ecosystems. Solid Earth Discussions 7:3645-3687. James JJ, Sheley RL, EricksonT, Rollins KS, Taylor MH, Dixon KW (2013) A systems approach to restoring degraded drylands. Journal of Applied Ecology 50:730-739. Muñoz-Rojas M., Erickson T, Merritt D, Dixon K (2014) Optimising post-mining soil conditions to maximise restoration success in a biodiverse semiarid environment. Geophysical Research. Abstracts Vol. 16, EGU2014-2069-1, EGU General Assembly. Muñoz-Rojas M, Erickson T, Merritt D, Dixon K (2015) Applying soil science for restoration of post mining degraded landscapes in semi-arid Australia: challenges and opportunities. Geophysical Research. Abstracts Vol. 17, EGU2015-3967-1, EGU General Assembly. Muñoz-Rojas M, Erickson TE, Martini D, Dixon KW, Merritt DJ (2016) Soil physicochemical and microbiological indicators of short, medium and long term post-fire recovery in semi-arid ecosystems. Ecological indicators 63:14-22. Willaarts BA, Oyonarte C, Muñoz-Rojas M., Ibáñez JJ and Aguilera PA (2015) Environmental Factors Controlling Soil Organic Carbon Stocks in Two Contrasting Mediterranean Climatic Areas of Southern Spain. Land Degradation and Development (on-line). DOI: 10.1002/ldr.2417

Impacts of precipitation and potential evapotranspiration patterns on downscaling soil moisture in regions with large topographic relief

NASA Astrophysics Data System (ADS)

Cowley, Garret S.; Niemann, Jeffrey D.; Green, Timothy R.; Seyfried, Mark S.; Jones, Andrew S.; Grazaitis, Peter J.

2017-02-01

Soil moisture can be estimated at coarse resolutions (>1 km) using satellite remote sensing, but that resolution is poorly suited for many applications. The Equilibrium Moisture from Topography, Vegetation, and Soil (EMT+VS) model downscales coarse-resolution soil moisture using fine-resolution topographic, vegetation, and soil data to produce fine-resolution (10-30 m) estimates of soil moisture. The EMT+VS model performs well at catchments with low topographic relief (≤124 m), but it has not been applied to regions with larger ranges of elevation. Large relief can produce substantial variations in precipitation and potential evapotranspiration (PET), which might affect the fine-resolution patterns of soil moisture. In this research, simple methods to downscale temporal average precipitation and PET are developed and included in the EMT+VS model, and the effects of spatial variations in these variables on the surface soil moisture estimates are investigated. The methods are tested against ground truth data at the 239 km2 Reynolds Creek watershed in southern Idaho, which has 1145 m of relief. The precipitation and PET downscaling methods are able to capture the main features in the spatial patterns of both variables. The space-time Nash-Sutcliffe coefficients of efficiency of the fine-resolution soil moisture estimates improve from 0.33 to 0.36 and 0.41 when the precipitation and PET downscaling methods are included, respectively. PET downscaling provides a larger improvement in the soil moisture estimates than precipitation downscaling likely because the PET pattern is more persistent through time, and thus more predictable, than the precipitation pattern.

Biodegradation of dimethylsilanediol in soils.

PubMed Central

Sabourin, C L; Carpenter, J C; Leib, T K; Spivack, J L

1996-01-01

The biodegradation potential of [14C]dimethylsilanediol, the monomer unit of polydimethylsiloxane, in soils was investigated. Dimethylsilanediol was found to be biodegraded in all of the tested soils, as monitored by the production of 14CO2. When 2-propanol was added to the soil as a carbon source in addition to [14C]dimethylsilanediol, the production of 14CO2 increased. A method for the selection of primary substrates that support cometabolic degradation of a target compound was developed. By this method, the activity observed in the soils was successfully transferred to liquid culture. A fungus, Fusarium oxysporum Schlechtendahl, and a bacterium, an Arthrobacter species, were isolated from two different soils, and both microorganisms were able to cometabolize [14C]dimethylsilanediol to 14CO2 in liquid culture. In addition, the Arthrobacter sp. that was isolated grew on dimethylsulfone, and we believe that this is the first reported instance of a microorganism using dimethylsulfone as its primary carbon source. Previous evidence has shown that polydimethylsiloxane is hydrolyzed in soil to the monomer, dimethylsilanediol. Now, biodegradation of dimethylsilanediol in soil has been demonstrated. PMID:8953708

Comparison Between Two Methods for Estimating the Vertical Scale of Fluctuation for Modeling Random Geotechnical Problems

NASA Astrophysics Data System (ADS)

Pieczyńska-Kozłowska, Joanna M.

2015-12-01

The design process in geotechnical engineering requires the most accurate mapping of soil. The difficulty lies in the spatial variability of soil parameters, which has been a site of investigation of many researches for many years. This study analyses the soil-modeling problem by suggesting two effective methods of acquiring information for modeling that consists of variability from cone penetration test (CPT). The first method has been used in geotechnical engineering, but the second one has not been associated with geotechnics so far. Both methods are applied to a case study in which the parameters of changes are estimated. The knowledge of the variability of parameters allows in a long term more effective estimation, for example, bearing capacity probability of failure.

Evaluating the utility of mid-infrared spectral subspaces for predicting soil properties.

PubMed

Sila, Andrew M; Shepherd, Keith D; Pokhariyal, Ganesh P

2016-04-15

We propose four methods for finding local subspaces in large spectral libraries. The proposed four methods include (a) cosine angle spectral matching; (b) hit quality index spectral matching; (c) self-organizing maps and (d) archetypal analysis methods. Then evaluate prediction accuracies for global and subspaces calibration models. These methods were tested on a mid-infrared spectral library containing 1907 soil samples collected from 19 different countries under the Africa Soil Information Service project. Calibration models for pH, Mehlich-3 Ca, Mehlich-3 Al, total carbon and clay soil properties were developed for the whole library and for the subspace. Root mean square error of prediction was used to evaluate predictive performance of subspace and global models. The root mean square error of prediction was computed using a one-third-holdout validation set. Effect of pretreating spectra with different methods was tested for 1st and 2nd derivative Savitzky-Golay algorithm, multiplicative scatter correction, standard normal variate and standard normal variate followed by detrending methods. In summary, the results show that global models outperformed the subspace models. We, therefore, conclude that global models are more accurate than the local models except in few cases. For instance, sand and clay root mean square error values from local models from archetypal analysis method were 50% poorer than the global models except for subspace models obtained using multiplicative scatter corrected spectra with which were 12% better. However, the subspace approach provides novel methods for discovering data pattern that may exist in large spectral libraries.

Review of Artificial Abrasion Test Methods for PV Module Technology

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

Miller, David C.; Muller, Matt T.; Simpson, Lin J.

This review is intended to identify the method or methods--and the basic details of those methods--that might be used to develop an artificial abrasion test. Methods used in the PV literature were compared with their closest implementation in existing standards. Also, meetings of the International PV Quality Assurance Task Force Task Group 12-3 (TG12-3, which is concerned with coated glass) were used to identify established test methods. Feedback from the group, which included many of the authors from the PV literature, included insights not explored within the literature itself. The combined experience and examples from the literature are intended tomore » provide an assessment of the present industry practices and an informed path forward. Recommendations toward artificial abrasion test methods are then identified based on the experiences in the literature and feedback from the PV community. The review here is strictly focused on abrasion. Assessment methods, including optical performance (e.g., transmittance or reflectance), surface energy, and verification of chemical composition were not examined. Methods of artificially soiling PV modules or other specimens were not examined. The weathering of artificial or naturally soiled specimens (which may ultimately include combined temperature and humidity, thermal cycling and ultraviolet light) were also not examined. A sense of the purpose or application of an abrasion test method within the PV industry should, however, be evident from the literature.« less

Theoretical Relationships between Luminescence and Hillslope Soil Vertical Diffusivity: a Numerical Modeling Approach

NASA Astrophysics Data System (ADS)

Gray, H. J.; Tucker, G. E.; Mahan, S.

2017-12-01

Luminescence is a property of matter that can be used to obtain depositional ages from fine sand. Luminescence generates due to exposure to background ionizing radiation and is removed by sunlight exposure in a process known as bleaching. There is evidence to suggest that luminescence can also serve as a sediment tracer in fluvial and hillslope environments. For hillslope environments, it has been suggested that the magnitude of luminescence as a function of soil depth is related to the strength of soil mixing. Hillslope soils with a greater extent of mixing will have previously surficial sand grains moved to greater depths in a soil column. These previously surface-exposed grains will contain a lower luminescence than those which have never seen the surface. To attempt to connect luminescence profiles with soil mixing rate, here defined as the soil vertical diffusivity, I conduct numerical modelling of particles in hillslope soils coupled with equations describing the physics of luminescence. I use recently published equations describing the trajectories of particles under both exponential and uniform soil velocity soils profiles and modify them to include soil diffusivity. Results from the model demonstrates a strong connection between soil diffusivity and luminescence. Both the depth profiles of luminescence and the total percent of surface exposed grains will change drastically based on the magnitude of the diffusivity. This suggests that luminescence could potentially be used to infer the magnitude of soil diffusivity. However, I test other variables such as the soil production rate, e-folding length of soil velocity, background dose rate, and soil thickness, and I find these other variables can also affect the relationship between luminescence and diffusivity. This suggests that these other variables may need to be constrained prior to any inferences of soil diffusivity from luminescence measurements. Further field testing of the model in areas where the soil vertical diffusivity and other parameters are independently known will provide a test of this potential new method.

Plastics in soil: Analytical methods and possible sources.

PubMed

Bläsing, Melanie; Amelung, Wulf

2018-01-15

At least 300 Mio t of plastic are produced annually, from which large parts end up in the environment, where it persists over decades, harms biota and enters the food chain. Yet, almost nothing is known about plastic pollution of soil; hence, the aims of this work are to review current knowledge on i) available methods for the quantification and identification of plastic in soil, ii) the quantity and possible input pathways of plastic into soil, (including first preliminary screening of plastic in compost), and iii) its fate in soil. Methods for plastic analyses in sediments can potentially be adjusted for application to soil; yet, the applicability of these methods for soil needs to be tested. Consequently, the current data base on soil pollution with plastic is still poor. Soils may receive plastic inputs via plastic mulching or the application of plastic containing soil amendments. In compost up to 2.38-1200mg plastic kg -1 have been found so far; the plastic concentration of sewage sludge varies between 1000 and 24,000 plastic items kg -1 . Also irrigation with untreated and treated wastewater (1000-627,000 and 0-125,000 plastic items m -3 , respectively) as well as flooding with lake water (0.82-4.42 plastic items m -3 ) or river water (0-13,751 items km -2 ) can provide major input pathways for plastic into soil. Additional sources comprise littering along roads and trails, illegal waste dumping, road runoff as well as atmospheric input. With these input pathways, plastic concentrations in soil might reach the per mill range of soil organic carbon. Most of plastic (especially >1μm) will presumably be retained in soil, where it persists for decades or longer. Accordingly, further research on the prevalence and fate of such synthetic polymers in soils is urgently warranted. Copyright © 2017 Elsevier B.V. All rights reserved.

Analysis of soil moisture extraction algorithm using data from aircraft experiments

NASA Technical Reports Server (NTRS)

Burke, H. H. K.; Ho, J. H.

1981-01-01

A soil moisture extraction algorithm is developed using a statistical parameter inversion method. Data sets from two aircraft experiments are utilized for the test. Multifrequency microwave radiometric data surface temperature, and soil moisture information are contained in the data sets. The surface and near surface ( or = 5 cm) soil moisture content can be extracted with accuracy of approximately 5% to 6% for bare fields and fields with grass cover by using L, C, and X band radiometer data. This technique is used for handling large amounts of remote sensing data from space.

Characterization of the spatial variability of soil available zinc at various sampling densities using grouped soil type information.

PubMed

Song, Xiao-Dong; Zhang, Gan-Lin; Liu, Feng; Li, De-Cheng; Zhao, Yu-Guo

2016-11-01

The influence of anthropogenic activities and natural processes involved high uncertainties to the spatial variation modeling of soil available zinc (AZn) in plain river network regions. Four datasets with different sampling densities were split over the Qiaocheng district of Bozhou City, China. The difference of AZn concentrations regarding soil types was analyzed by the principal component analysis (PCA). Since the stationarity was not indicated and effective ranges of four datasets were larger than the sampling extent (about 400 m), two investigation tools, namely F3 test and stationarity index (SI), were employed to test the local non-stationarity. Geographically weighted regression (GWR) technique was performed to describe the spatial heterogeneity of AZn concentrations under the non-stationarity assumption. GWR based on grouped soil type information (GWRG for short) was proposed so as to benefit the local modeling of soil AZn within each soil-landscape unit. For reference, the multiple linear regression (MLR) model, a global regression technique, was also employed and incorporated the same predictors as in the GWR models. Validation results based on 100 times realization demonstrated that GWRG outperformed MLR and can produce similar or better accuracy than the GWR approach. Nevertheless, GWRG can generate better soil maps than GWR for limit soil data. Two-sample t test of produced soil maps also confirmed significantly different means. Variogram analysis of the model residuals exhibited weak spatial correlation, rejecting the use of hybrid kriging techniques. As a heuristically statistical method, the GWRG was beneficial in this study and potentially for other soil properties.

[Antagonism in vitro among phytopathogenic and saprobic fungi from horticultural soils].

PubMed

Alippi, H E; Monaco, C

1990-01-01

Two methods were tested in order to determine the existence of in vitro antagonism among saprobic and pathogenic fungi. These microorganisms were the most common isolates from horticultural soils of La Plata (Buenos Aires). Trichoderma harzianum; T. koningii and Penicillium sp. were antagonistic to all the pathogenic fungi tested, Fusarium solani; F. oxysporum; Alternaria solani; Colletotrichum sp. and Sclerotium rolfsii Spicaria sp., Paecilomyces sp. and Chaetomiun sp. were antagonistic only to Colletotrichum sp. and Fusarium solani.

Geostatistics, remote sensing and precision farming.

PubMed

Mulla, D J

1997-01-01

Precision farming is possible today because of advances in farming technology, procedures for mapping and interpolating spatial patterns, and geographic information systems for overlaying and interpreting several soil, landscape and crop attributes. The key component of precision farming is the map showing spatial patterns in field characteristics. Obtaining information for this map is often achieved by soil sampling. This approach, however, can be cost-prohibitive for grain crops. Soil sampling strategies can be simplified by use of auxiliary data provided by satellite or aerial photo imagery. This paper describes geostatistical methods for estimating spatial patterns in soil organic matter, soil test phosphorus and wheat grain yield from a combination of Thematic Mapper imaging and soil sampling.

Production and transport of gases in the soil: from 1-D soil gas profiles towards 2- and 3-D representations of soil gas processes

NASA Astrophysics Data System (ADS)

Maier, Martin; Lang, Friederike; Schack-Kirchner, Helmer

2017-04-01

Most studies implicitly use a 1 dimensional simplification of soil processes with a dominating vertical profile, e.g in soil physical and chemical properties. In many cases, this is a useful and sufficient representation of the realty which helps to answer research questions in an efficient way. Yet, in some cases, a 2 D or 3 D analysis of the processes is necessary to avoid misinterpretation of experimental results, e.g. modeling the impact of chamber deployment time during the measurement of gas fluxes (von Fischer et al. 2009) or trenching experiments (Jassal et al. 2006). We developed a new method to determine the 2 D patterns of the soil gas diffusion coefficient DS/D0 in situ, using simultaneously several inert tracer gases. Soil gas transport was modelled inversely using the Finite Element Modeling program COMSOL. In combination with measurements of target gases such as CO2, CH4 and N2O, this allowed us for modelling the 2-D patterns of transport and production of CO2, CH4 and N2O in the soil. We observed how methane oxidation and soil respiration zones shifted within the soil profile while the gas fluxes at the surface remain rather stable during a 3 week campaign. The soil was a net sink for N2O, yet, in the subsoil local (weak) source of N2O lead to horizontal fluxes of N2O. We are testing the 3 D approach in the lab on defined substrates and objects to quantify the spatial resolution and reliability of the method. In a next step, we want to test the method in the field and study the ventilation and soil gas fluxes of an ant nest in 3D. References: von Fischer, J. C., G. Butters, P. C. Duchateau, R. J. Thelwell, and R. Siller (2009), In situ measures of methanotroph activity in upland soils: A reaction-diffusion model and field observation of water stress, J. Geophys. Res., 114, G01015, Jassal RS, Black TA (2006) Estimating heterotrophic and autotrophic soil respiration using small-area trenched plot technique: theory and practice. Agric. For. Meteorol. 140:193-202

Methods to ensure the quality of excavated soil material from geogenically metalliferous sites

NASA Astrophysics Data System (ADS)

Liebhard, Peter; Sager, Manfred

2017-04-01

Soils at geogenically metalliferous sites might exceed heavy metal threshold levels with respect to agricultural use, apart from anthropogenic contamination sources. As a fundamental substrate for green plants and green plant production, soil is not easily renewable, its formation needs long time (e.g. 500 years for 20 mm). In Austria, about 10ha of soil get sealed every day, resulting in complete loss of its biological functions. Excavated soil material has been classified as waste from a legal point of view, which made 33 mill. tons resp. 48% of total waste in Austria in 2010. Recycling of excavated soil material for agricultural use will be an important task to reduce future waste and to enlarge agricultural substrate volumes, but methods to ensure proper qualities are needed to improve regulations. Within this investigation, the transfer of various metals from geogenically metalliferous soils to various crop plants will be investigated, and correlated with various simple soil test methods. Four excavated soil materials from the metalliferous schist zone within the Austrian province of Styria (Kraubath/Mur, Übelbach) and a low-metal reference sample have been taken as substrates to grow raygrass (lolium multiflorum) as a green cover, salad (Lactuca sativa) as a vegetable food item, oats (Avena sativa), maize (Zea mais) and stinging nettle (Urtica dioica) as a hyperaccumulating species. Results and recommendations will be presented.

Incorporating availability/bioavailability in risk assessment and decision making of polluted sites, using Germany as an example.

PubMed

Kördel, Werner; Bernhardt, Cornelia; Derz, Kerstin; Hund-Rinke, Kerstin; Harmsen, Joop; Peijnenburg, Willie; Comans, Rob; Terytze, Konstantin

2013-10-15

Nearly all publications dealing with availability or bioavailability of soil pollutants start with the following statement: the determination of total pollutant content will lead to an over-estimation of risk. However, an assessment of contaminated sites should be based on the determination of mobile fractions of pollutants, and the fractions with potential for mobilisation that threaten groundwater and surface water, and the actual and potential fractions available for uptake by plants, soil microflora and soil organisms. After reviewing the literature for method proposals concerning the determination of available/bioavailable fractions of contaminants with respect to leaching, plants, microorganisms (biodegradation) and soil organisms, we propose a testing and assessment scheme for contaminated sites. The proposal includes (i) already accepted and used methods, (ii) methods which are under standardisation, and (iii) methods for which development has just started in order to promote urgently needed research. Copyright © 2013 Elsevier B.V. All rights reserved.

Regional Characterization of Soil Properties via a Combination of Methods from Remote Sensing, Geophysics and Geopedology

NASA Astrophysics Data System (ADS)

Meyer, Uwe; Fries, Elke; Frei, Michaela

2016-04-01

Soil is one of the most precious resources on Earth. Preserving, using and enriching soils are most complex processes that fundamentally need a sound regional data base. Many countries lack this sort of extensive data or the existing data must be urgently updated when land use recently changed in major patterns. The project "RECHARBO" (Regional Characterization of Soil Properties) aims at the combination of methods from remote sensing, geophysics and geopedology in order to develop a new system to map soils on a regional scale in a quick and efficient manner. First tests will be performed on existing soil monitoring districts, using newly available sensing systems as well as established techniques. Especially hyperspectral and infrared data measured from satellites or airborne platforms shall be combined. Moreover, a systematic correlation between hyperspectral imagery and gamma-ray spectroscopy shall be established. These recordings will be compared and correlated to measurements upon ground and on soil samples to get hold of properties such as soil moisture, soil density, specific resistance plus analytic properties like clay content, anorganic background, organic matter etc. The goal is to generate a system that enables users to map soil patterns on a regional scale using airborne or satellite data and to fix their characteristics with only a limited number of soil samples.

Prediction of near-surface soil moisture at large scale by digital terrain modeling and neural networks.

PubMed

Lavado Contador, J F; Maneta, M; Schnabel, S

2006-10-01

The capability of Artificial Neural Network models to forecast near-surface soil moisture at fine spatial scale resolution has been tested for a 99.5 ha watershed located in SW Spain using several easy to achieve digital models of topographic and land cover variables as inputs and a series of soil moisture measurements as training data set. The study methods were designed in order to determining the potentials of the neural network model as a tool to gain insight into soil moisture distribution factors and also in order to optimize the data sampling scheme finding the optimum size of the training data set. Results suggest the efficiency of the methods in forecasting soil moisture, as a tool to assess the optimum number of field samples, and the importance of the variables selected in explaining the final map obtained.

Geotechnical Parameters of Alluvial Soils from in-situ Tests

NASA Astrophysics Data System (ADS)

Młynarek, Zbigniew; Stefaniak, Katarzyna; Wierzbicki, Jędrzej

2012-10-01

The article concentrates on the identification of geotechnical parameters of alluvial soil represented by silts found near Poznan and Elblag. Strength and deformation parameters of the subsoil tested were identified by the CPTU (static penetration) and SDMT (dilatometric) methods, as well as by the vane test (VT). Geotechnical parameters of the subsoil were analysed with a view to using the soil as an earth construction material and as a foundation for buildings constructed on the grounds tested. The article includes an analysis of the overconsolidation process of the soil tested and a formula for the identification of the overconsolidation ratio OCR. Equation 9 reflects the relation between the undrained shear strength and plasticity of the silts analyzed and the OCR value. The analysis resulted in the determination of the Nkt coefficient, which might be used to identify the undrained shear strength of both sediments tested. On the basis of a detailed analysis of changes in terms of the constrained oedometric modulus M0, the relations between the said modulus, the liquidity index and the OCR value were identified. Mayne's formula (1995) was used to determine the M0 modulus from the CPTU test. The usefullness of the sediments found near Poznan as an earth construction material was analysed after their structure had been destroyed and compacted with a Proctor apparatus. In cases of samples characterised by different water content and soil particle density, the analysis of changes in terms of cohesion and the internal friction angle proved that these parameters are influenced by the soil phase composition (Fig. 18 and 19). On the basis of the tests, it was concluded that the most desirable shear strength parameters are achieved when the silt is compacted below the optimum water content.

Geotechnical Parameters of Alluvial Soils from in-situ Tests

NASA Astrophysics Data System (ADS)

Młynarek, Zbigniew; Stefaniak, Katarzyna; Wierzbicki, Jedrzej

2012-10-01

The article concentrates on the identification of geotechnical parameters of alluvial soil represented by silts found near Poznan and Elblag. Strength and deformation parameters of the subsoil tested were identified by the CPTU (static penetration) and SDMT (dilatometric) methods, as well as by the vane test (VT). Geotechnical parameters of the subsoil were analysed with a view to using the soil as an earth construction material and as a foundation for buildings constructed on the grounds tested. The article includes an analysis of the overconsolidation process of the soil tested and a formula for the identification of the overconsolidation ratio OCR. Equation 9 reflects the relation between the undrained shear strength and plasticity of the silts analyzed and the OCR value. The analysis resulted in the determination of the Nkt coefficient, which might be used to identify the undrained shear strength of both sediments tested. On the basis of a detailed analysis of changes in terms of the constrained oedometric modulus M0, the relations between the said modulus, the liquidity index and the OCR value were identified. Mayne's formula (1995) was used to determine the M0 modulus from the CPTU test. The usefullness of the sediments found near Poznan as an earth construction material was analysed after their structure had been destroyed and compacted with a Proctor apparatus. In cases of samples characterised by different water content and soil particle density, the analysis of changes in terms of cohesion and the internal friction angle proved that these parameters are influenced by the soil phase composition (Fig. 18 and 19). On the basis of the tests, it was concluded that the most desirable shear strength parameters are achieved when the silt is compacted below the optimum water content.

Improved Absolute Radiometric Calibration of a UHF Airborne Radar

NASA Technical Reports Server (NTRS)

Chapin, Elaine; Hawkins, Brian P.; Harcke, Leif; Hensley, Scott; Lou, Yunling; Michel, Thierry R.; Moreira, Laila; Muellerschoen, Ronald J.; Shimada, Joanne G.; Tham, Kean W.;

A Geostatistical Toolset for Reconstructing Louisiana's Coastal Stratigraphy using Subsurface Boring and Cone Penetrometer Test Data

NASA Astrophysics Data System (ADS)

Li, A.; Tsai, F. T. C.; Jafari, N.; Chen, Q. J.; Bentley, S. J.

2017-12-01

A vast area of river deltaic wetlands stretches across southern Louisiana coast. The wetlands are suffering from a high rate of land loss, which increasingly threats coastal community and energy infrastructure. A regional stratigraphic framework of the delta plain is now imperative to answer scientific questions (such as how the delta plain grows and decays?) and to provide information to coastal protection and restoration projects (such as marsh creation and construction of levees and floodwalls). Through years, subsurface investigations in Louisiana have been conducted by state and federal agencies (Louisiana Department of Natural Resources, United States Geological Survey, United States Army Corps of Engineers, etc.), research institutes (Louisiana Geological Survey, LSU Coastal Studies Institute, etc.), engineering firms, and oil-gas companies. This has resulted in the availability of various types of data, including geological, geotechnical, and geophysical data. However, it is challenging to integrate different types of data and construct three-dimensional stratigraphy models in regional scale. In this study, a set of geostatistical methods were used to tackle this problem. An ordinary kriging method was used to regionalize continuous data, such as grain size, water content, liquid limit, plasticity index, and cone penetrometer tests (CPTs). Indicator kriging and multiple indicator kriging methods were used to regionalize categorized data, such as soil classification. A compositional kriging method was used to regionalize compositional data, such as soil composition (fractions of sand, silt and clay). Stratigraphy models were constructed for three cases in the coastal zone: (1) Inner Harbor Navigation Canal (IHNC) area: soil classification and soil behavior type (SBT) stratigraphies were constructed using ordinary kriging; (2) Middle Barataria Bay area: a soil classification stratigraphy was constructed using multiple indicator kriging; (3) Lower Barataria Bay and Lower Breton Sound areas: a soil texture stratigraphy was constructed using soil compositional data and compositional kriging. Cross sections were extracted from the three-dimensional stratigraphy models to reveal spatial distributions of different stratigraphic features.

Determination of the saturated film conductivity to improve the EMFX model in describing the soil hydraulic properties over the entire moisture range

NASA Astrophysics Data System (ADS)

Wang, Yunquan; Ma, Jinzhu; Guan, Huade; Zhu, Gaofeng

2017-06-01

Difficulty in measuring hydraulic conductivity, particularly under dry conditions, calls for methods of predicting the conductivity from easily obtained soil properties. As a complement to the recently published EMFX model, a method based on two specific suction conditions is proposed to estimate saturated film conductivity from the soil water retention curve. This method reduces one fitting parameter in the previous EMFX model, making it possible to predict the hydraulic conductivity from the soil water retention curve over the complete moisture range. Model performance is evaluated with published data of soils in a broad texture range from sand to clay. The testing results indicate that 1) the modified EMFX model (namely the EMFX-K model), incorporating both capillary and adsorption forces, provides good agreement with the conductivity data over the entire moisture range; 2) a value of 0.5 for the tortuosity factor in the EMFX-K model as that in the Mualem's model gives comparable estimation of the relative conductivity associated with the capillary force; and 3) a value of -1.0 × 10-20 J for the Hamaker constant, rather than the commonly used value of -6.0 × 10-20 J, appears to be more appropriate to represent solely the effect of the van der Waals forces and to predict the film conductivity. In comparison with the commonly used van Genuchten-Mualem model, the EMFX-K model significantly improves the prediction of hydraulic conductivity under dry conditions. The sensitivity analysis result suggests that the uncertainty in the film thickness estimation is important in explaining the model underestimation of hydraulic conductivity for the soils with fine texture, in addition to the uncertainties from the measurements and the model structure. High quality data that cover the complete moisture range for a variety of soil textures are required to further test the method.

A method for testing land resource area concepts

USDA-ARS?s Scientific Manuscript database

Land Resource Units (LRUs) are defined by the National Soil Survey Handbook as aggregations of soil map units and subunits of Major Land Resource Areas (MLRAs). In the USDA NRCS Land Resource Hierarchy, LRUs are defined as the level between MLRAs and STATSGO and are mapped at 1:1 million scale. They...

Field assessment of wood stake decomposition in forest soil

Treesearch

Xiping Wang; Deborah Page-Dumroese; Martin F. Jurgensen; Robert J. Ross

2007-01-01

A pulse-echo acoustic method was investigated for evaluating wood stake decomposition in the field. A total of 58 wood stakes (29 loblolly pine, Pinus taeda, and 29 aspen, Populus tremuloides) that were vertically installed (full length) in forest soils were non-destructively tested by means of a laboratory-type acoustic...

Evaluation of tests to assess the quality of mine-contaminated soils.

PubMed

Alvarenga, P; Palma, P; Gonçalves, A P; Fernandes, R M; de Varennes, A; Vallini, G; Duarte, E; Cunha-Queda, A C

2008-04-01

An acid metal-contaminated soil from the Aljustrel mining area (a pyrite mine located in SW Portugal in the Iberian Pyrite Belt) was subjected to chemical characterisation and total metal quantification (Cd, Cr, Cu, Ni, Pb and Zn). Water-soluble metals were determined and a sequential extraction procedure was used to investigate metal speciation. Two bioavailable metal fractions were determined: a mobile fraction and a mobilisable fraction. Soil ecotoxicity was studied using a battery of bioassays: plant growth test and seed germination with cress (Lepidium sativum L.), earthworm (Eisenia fetida) mortality, E. fetida avoidance behaviour, luminescent inhibition of Vibrio fischeri and Daphnia magna immobilisation. Although the total content of Cu, Zn and Pb in the soil was large (362, 245 and 1,250 mg/kg dry matter, respectively), these metals were mostly structurally bound (87% for Cu, 81% for Zn and 89% for Pb) and, therefore, scarcely bioavailable. Nonetheless, the D. magna immobilization test using soil leachate showed an EC50 (48 h) of 36.3% (v/v), and the luminescent inhibition of V. fischeri presented an EC20 (15 min) of 45.2% and an EC20 (30 min) of 10.7% (v/v), suggesting a considerable toxic effect. In the direct exposure bioassays, E. fetida avoided the mine soil at the highest concentrations (50%, 75% and 100% v/v). At the same soil concentrations, cress showed negligible growth. The results suggest the need to use a battery of toxicity tests, in conjunction with chemical methods, in order to assess the quality of mine-contaminated soils correctly.

Keeping soil in the field - runoff and erosion management in asparagus crops

NASA Astrophysics Data System (ADS)

Niziolomski, Joanna; Simmons, Robert; Rickson, Jane; Hann, Mike

2016-04-01

Row crop production (including potatoes, onions, carrots, asparagus, bulbs and lettuce) is regarded as one of the most erosive agricultural cropping systems. This is a result of the many practices involved that increase erosion risk including: fine seedbed preparation, a typically short growing season where adequate ground cover protects the soil, permanent bare soil areas between crops, and often intensive harvesting methods that can damage soil structure and result in soil compaction. Sustained exposure of bare soil coupled with onsite compaction on slightly sloping land results in soil and water issues in asparagus production. Asparagus production is a growing British industry covering > 2000 ha and is worth approximately £30 million yr-1. However, no tried and tested erosion control measurements currently exist to manage associated problems. Research has recently been undertaken investigating the effectiveness of erosion control measures suitable for asparagus production systems. These consisted of surface applied wheat straw mulch and shallow soil disturbance (< 350 mm) using several tine configurations: a currently adopted winged tine, a narrow with two shallow leading tines, and a modified para-plough. These treatments were tested individually and in combination (straw mulch with each shallow soil disturbance tine configuration) using triplicated field plots situated on a working asparagus farm in Herefordshire, UK. Testing was conducted between May and November 2013. Rainfall-event based runoff and erosion measurements were taken including; runoff volume, runoff rate and total soil loss. Runoff and soil erosion was observed from all treatments. However, the surface application of straw mulch alone out performed each shallow soil disturbance practice. This suggests that runoff and erosion from asparagus production can be reduced using the simple surface application of straw.

Electrogeochemical sampling with NEOCHIM - results of tests over buried gold deposits

USGS Publications Warehouse

Leinz, R.W.; Hoover, D.B.; Fey, D.L.; Smith, D.B.; Patterson, T.

1998-01-01

Electrogeochemical extraction methods are based on the migration of ions in an electric field. Ions present in soil moisture are transported by an applied current into fluids contained in special electrodes placed on the soil. The fluids are then collected and analyzed. Extractions are governed by Faraday's and Ohm's laws and are modeled by the operation of a simple Hittord transference apparatus. Calculations show that the volume of soil sampled in an ideal electrogeochemical extraction can be orders of magnitude greater than the volumes used in more popular geochemical extraction methods, although this has not been verified experimentally. CHIM is a method of in-situ electrogeochemical extraction that was developed in the former Soviet Union and has been tested and applied internationally to exploration for buried mineral deposits. Tests carried out at the US Geological Survey (USGS) indicated that there were problems inherent in the use of CHIM technology. The cause of the problems was determined to be the diffusion of acid from the conventional electrode into the soil. The NEOCHIM electrode incorporates two compartments and a salt bridge in a design that inhibits diffusion of acid and enables the collection of anions or cations. Tests over a gold-enriched vein in Colorado and over buried, Carlin-type, disseminated gold deposits in northern Nevada show that there are similarities and differences between NEOCHIM results and those by partial extractions of soils which include simple extractions with water, dilute acids and solutions of salts used as collector fluids in the electrodes. Results of both differ from the results obtained by total chemical digestion. The results indicate that NEOCHIM responds to mineralized faults associated with disseminated gold deposits whereas partial and total chemical extraction methods do not. This suggests that faults are favored channels for the upward migration of metals and that NEOCHIM may be more effective in exploration for the deposits. It defines anomalies that are often narrow and intense, an observation previously made by CHIM researchers. The field tests show that NEOCHIM is less affected by surface contamination. A test over the Mike disseminated gold deposit indicates that the method may not be effective for locating deposits with impermeable cover. Faradaic extraction efficiencies of 20-30%, or more, are frequently achieved with NEOCHIM and the method generally shows good reproducibility, especially in extraction of major cations. However, ions of other metals that are useful in exploration, including Au and As, may be collected in low and temporally variable concentrations. The reason for this variability is unclear and requires further investigation.CHIM is a method of in-situ electrogeochemical extraction developed for the exploration of buried mineral deposits. However, electrode problems like diffusion of acid into the soil were encountered during the use of CHIM. The NEOCHIM electrode was developed to inhibit the diffusion of acid and enable collection of anions or cations. Tests over buried gold deposits showed that NEOCHIM responds to mineralized faults associated with disseminated gold deposits whereas partial and total chemical extraction methods do not. This suggests that faults are favored channels for the upward migration of metals and NEOCHIM may be effective in exploration for the deposits. But ions of metals may be collected in low and variable concentration.

A method for modeling the effects of climate and land use changes on erosion and sustainability of soil in a Mediterranean watershed (Languedoc, France).

PubMed

Paroissien, Jean-Baptiste; Darboux, Frédéric; Couturier, Alain; Devillers, Benoît; Mouillot, Florent; Raclot, Damien; Le Bissonnais, Yves

2015-03-01

Global climate and land use changes could strongly affect soil erosion and the capability of soils to sustain agriculture and in turn impact regional or global food security. The objective of our study was to develop a method to assess soil sustainability to erosion under changes in land use and climate. The method was applied in a typical mixed Mediterranean landscape in a wine-growing watershed (75 km(2)) within the Languedoc region (La Peyne, France) for two periods: a first period with the current climate and land use and a second period with the climate and land use scenarios at the end of the twenty-first century. The Intergovernmental Panel on Climate Change A1B future rainfall scenarios from the Météo France General circulation model was coupled with four contrasting land use change scenarios that were designed using a spatially-explicit land use change model. Mean annual erosion rate was estimated with an expert-based soil erosion model. Soil life expectancy was assessed using soil depth. Soil erosion rate and soil life expectancy were combined into a sustainability index. The median simulated soil erosion rate for the current period was 3.5 t/ha/year and the soil life expectancy was 273 years, showing a low sustainability of soils. For the future period with the same land use distribution, the median simulated soil erosion rate was 4.2 t/ha/year and the soil life expectancy was 249 years. The results show that soil erosion rate and soil life expectancy are more sensitive to changes in land use than to changes in precipitation. Among the scenarios tested, institution of a mandatory grass cover in vineyards seems to be an efficient means of significantly improving soil sustainability, both in terms of decreased soil erosion rates and increased soil life expectancies. Copyright © 2014 Elsevier Ltd. All rights reserved.

Non-Invasive Seismic Methods for Earthquake Site Classification Applied to Ontario Bridge Sites

NASA Astrophysics Data System (ADS)

Bilson Darko, A.; Molnar, S.; Sadrekarimi, A.

2017-12-01

How a site responds to earthquake shaking and its corresponding damage is largely influenced by the underlying ground conditions through which it propagates. The effects of site conditions on propagating seismic waves can be predicted from measurements of the shear wave velocity (Vs) of the soil layer(s) and the impedance ratio between bedrock and soil. Currently the seismic design of new buildings and bridges (2015 Canadian building and bridge codes) requires determination of the time-averaged shear-wave velocity of the upper 30 metres (Vs30) of a given site. In this study, two in situ Vs profiling methods; Multichannel Analysis of Surface Waves (MASW) and Ambient Vibration Array (AVA) methods are used to determine Vs30 at chosen bridge sites in Ontario, Canada. Both active-source (MASW) and passive-source (AVA) surface wave methods are used at each bridge site to obtain Rayleigh-wave phase velocities over a wide frequency bandwidth. The dispersion curve is jointly inverted with each site's amplification function (microtremor horizontal-to-vertical spectral ratio) to obtain shear-wave velocity profile(s). We apply our non-invasive testing at three major infrastructure projects, e.g., five bridge sites along the Rt. Hon. Herb Gray Parkway in Windsor, Ontario. Our non-invasive testing is co-located with previous invasive testing, including Standard Penetration Test (SPT), Cone Penetration Test and downhole Vs data. Correlations between SPT blowcount and Vs are developed for the different soil types sampled at our Ontario bridge sites. A robust earthquake site classification procedure (reliable Vs30 estimates) for bridge sites across Ontario is evaluated from available combinations of invasive and non-invasive site characterization methods.

Open charcoal chamber method for mass measurements of radon exhalation rate from soil surface.

PubMed

Tsapalov, Andrey; Kovler, Konstantin; Miklyaev, Peter

2016-08-01

Radon exhalation rate from the soil surface can serve as an important criterion in the evaluation of radon hazard of the land. Recently published international standard ISO 11665-7 (2012) is based on the accumulation of radon gas in a closed container. At the same time since 1998 in Russia, as a part of engineering and environmental studies for the construction, radon flux measurements are made using an open charcoal chamber for a sampling duration of 3-5 h. This method has a well-defined metrological justification and was tested in both favorable and unfavorable conditions. The article describes the characteristics of the method, as well as the means of sampling and measurement of the activity of radon absorbed. The results of the metrological study suggest that regardless of the sampling conditions (weather, the mechanism and rate of radon transport in the soil, soil properties and conditions), uncertainty of method does not exceed 20%, while the combined standard uncertainty of radon exhalation rate measured from the soil surface does not exceed 30%. The results of the daily measurements of radon exhalation rate from the soil surface at the experimental site during one year are reported. Copyright © 2016 Elsevier Ltd. All rights reserved.

Soil column leaching of pesticides.

PubMed

Katagi, Toshiyuki

2013-01-01

In this review, I address the practical and theoretical aspects of pesticide soil mobility.I also address the methods used to measure mobility, and the factors that influence it, and I summarize the data that have been published on the column leaching of pesticides.Pesticides that enter the unsaturated soil profile are transported downwards by the water flux, and are adsorbed, desorbed, and/or degraded as they pass through the soil. The rate of passage of a pesticide through the soil depends on the properties of the pesticide, the properties of the soil and the prevailing environmental conditions.Because large amounts of many different pesticides are used around the world, they and their degradates may sometimes contaminate groundwater at unacceptable levels.It is for this reason that assessing the transport behavior and soil mobility of pesticides before they are sold into commerce is important and is one indispensable element that regulators use to assess probable pesticide safety. Both elementary soil column leaching and sophisticated outdoor lysimeter studies are performed to measure the leaching potential for pesticides; the latter approach more reliably reflects probable field behavior, but the former is useful to initially profile a pesticide for soil mobility potential.Soil is physically heterogeneous. The structure of soil varies both vertically and laterally, and this variability affects the complex flow of water through the soil profile, making it difficult to predict with accuracy. In addition, macropores exist in soils and further add to the complexity of how water flow occurs. The degree to which soil is tilled, the density of vegetation on the surface, and the type and amounts of organic soil amendments that are added to soil further affect the movement rate of water through soil, the character of soil adsorption sites and the microbial populations that exist in the soil. Parameters that most influence the rate of pesticide mobility in soil are persistence (DT50) of the pesticide, and its sorption/desorption(Koc) characteristics. These parameters may vary for the same pesticide from geographic site-to-site and with soil depth. The interactions that normally occur between pesticides and dissolved organic matter (DOM) or WDC are yet other factors that may complicate pesticide leaching behavior.The soil mobility of pesticides is normally tested both in the laboratory and in the field. Lab studies are initially performed to give researchers a preliminary appraisal of the relative mobility of a pesticide. Later, field lysimeter studies can be performed to provide more natural leaching conditions that emulate the actual field use pattern. Lysimeter studies give the most reliable information on the leaching behavior of a pesticide under field conditions, but these studies are time-consuming and expensive and cannot be performed everywhere. It is for this reason that the laboratory soil column leaching approach is commonly utilized to profile the mobility of a pesticide,and appraise how it behaves in different soils, and relative to other pesticides.Because the soil structure is chemically and physically heterogenous, different pesticide tests may produce variable DT50 and Koc values; therefore, initial pesticide mobility testing is undertaken in homogeneously packed columns that contain two or more soils and are eluted at constant flow rates. Such studies are done in duplicate and utilize a conservative tracer element. By fitting an appropriate mathematical model to the breakthrough curve of the conservative tracer selected,researchers determine key mobility parameters, such as pore water velocity, the column-specific dispersion coefficient, and the contribution of non equilibrium transport processes. Such parameters form the basis for estimating the probable transport and degradation rates that will be characteristic of the tested pesticide. Researchers also examine how a pesticide interacts with soil DOM and WDC, and what contribution from facilitated transport to mobility is made as a result of the effects of pH and ionic strength. Other methods are used to test how pesticides may interact with soil components to change mobility. Spectroscopic approaches are used to analyze the nature of soil pesticide complexes. These may provide insight into the mechanism by which interactions occur. Other studies may be performed to determine the effect of agricultural practices (e.g., tillage) on pesticide leaching under controlled conditions using intact soil cores from the field. When preferential flow is suspected to occur, dye staining is used to examine the contribution of macropores to pesticide transport. These methods and others are addressed in the text of this review.

[Convertibility of the data determined by ICP-AES and FAAS for soil available K and Na].

PubMed

Zhang, Jian-min; Wang, Meng; Ge, Xiao-ping; Wu, Jian-zhi; Ge, Ying; Li, Shi-peng; Chang, Jie

2009-05-01

In recent years, inductively coupled plasma atomic emission spectrometry (ICP-AES) have been commonly used to determine the soil available K and Na with the extraction solution of HCl-H2SO4, while previous data of soil available K and Na were measured by flame atomic absorption spectrometry (FAAS) with the extraction solution of NH4OAc. In order to utilize previous data, quest for the convertibility of the data determined by ICP-AES and FAAS, and compare the data determined by both methods, the authors chose four types of soil to determine soil available K and Na by ICP-AES and FAAS, respectively. Four types of soil represent grit soil, clay, silt from river and silt from sea, respectively. Soil samples included four types of soil and these samples represent different soil nutrition. The authors analyzed the correlations of two kinds of measured data. The paired samples t-test proves that there was significantly positively correlation between these two methods. The correlation coefficient of the data between these two methods for measuring soil available K is 0.98. The results of soil available K determined by the two methods can be conversed through the formula, y = l.14x + 6.53 (R2 = 0.91, n=24, p < 0.001). As for Na, although there is a significantly positively correlation between these two methods, the slopes of single model of clay and grit soil were different from that of general model. And so the results determined by the two methods can be conversed through different formula according to the types of soil, that is, for clay: y = l.23x + 10.03; for grit soil: y = 3.12x - 23.03; for silt: y = 0.60x. In conclusion, the authors' results showed that previous data of available K and Na measured by FAAS with the extraction solution of NH4OAc were available. And these data were comparable to the data measured by ICP-AES through definite formula The authors' results also suggested that ICP-AES was preferable when many elements were measured at the same time. Under this condition, ICP-AES was economical, efficient and reliable.

Testosterone sorption and desorption: effects of soil particle size.

PubMed

Qi, Yong; Zhang, Tian C; Ren, Yongzheng

2014-08-30

Soils contain a wide range of particles of different diameters with different mobility during rainfall events. Effects of soil particles on sorption and desorption behaviors of steroid hormones have not been investigated. In this study, wet sieve washing and repeated sedimentation methods were used to fractionate the soils into five ranges. The sorption and desorption properties and related mechanisms of testosterone in batch reactors filled with fractionated soil particles were evaluated. Results of sorption and desorption kinetics indicate that small soil particles have higher sorption and lower desorption rates than that of big ones. Thermodynamic results show the sorption processes are spontaneous and exothermal. The sorption capacity ranks as clay>silt>sand, depending mainly on specific surface area and surface functional groups. The urea control test shows that hydrogen bonding contributes to testosterone sorption onto clay and silt but not on sand. Desorption tests indicate sorption is 36-65% irreversible from clay to sand. Clays have highest desorption hysteresis among these five soil fractions, indicating small particles like clays have less potential for desorption. The results provide indirect evidence on the colloid (clay)-facilitated transport of hormones (micro-pollutants) in soil environments. Copyright © 2014 Elsevier B.V. All rights reserved.

Measuring lateral saturated soil hydraulic conductivity at different spatial scales

NASA Astrophysics Data System (ADS)

Di Prima, Simone; Marrosu, Roberto; Pirastru, Mario; Niedda, Marcello

2017-04-01

Among the soil hydraulic properties, saturated soil hydraulic conductivity, Ks, is particularly important since it controls many hydrological processes. Knowledge of this soil property allows estimation of dynamic indicators of the soil's ability to transmit water down to the root zone. Such dynamic indicators are valuable tools to quantify land degradation and developing 'best management' land use practice (Castellini et al., 2016; Iovino et al., 2016). In hillslopes, lateral saturated soil hydraulic conductivity, Ks,l, is a key factor since it controls subsurface flow. However, Ks,l data collected by point-scale measurements, including infiltrations tests, could be unusable for interpreting field hydrological processes and particularly subsurface flow in hillslopes. Therefore, they are generally not representative of subsurface processes at hillslope-scale due mainly to soil heterogeneities and the unknown total extent and connectivity of macropore network in the porous medium. On the other hand, large scale Ks,l measurements, which allow to average soil heterogeneities, are difficult and costly, thus remain rare. Reliable Ks,l values should be measured on a soil volume similar to the representative elementary volume (REV) in order to incorporate the natural heterogeneity of the soil. However, the REV may be considered site-specific since it is expected to increase for soils with macropores (Brooks et al., 2004). In this study, laboratory and in-situ Ks,l values are compared in order to detect the dependency Ks,l from the spatial scale of investigation. The research was carried out at a hillslope located in the Baratz Lake watershed, in northwest Sardinia, Italy, characterized by degraded vegetation (grassland established after fire or clearing of the maquis). The experimental area is about 60 m long, with an extent of approximately 2000 m2, and a mean slope of 30%. The soil depth is about 35 to 45 cm. The parent material is a very dense grayish, altered substratum of Permian sandstone that exhibits very low drainage, thus preventing deep water percolation (Castellini et al., 2016). In the laboratory, small-scale lateral and vertical saturated hydraulic conductivity, Ks,v, were determined by the constant-head permeameter method (Klute and Dirksen, 1986) on 20 soil cubes of 1331 cm3 of volume (Bagarello and Sgroi, 2008), allowing determination of mean Ks anisotropy for the hillslope. In the field, small-scale Ks,v was determined by infiltration runs of the BEST (Lassabatere et al., 2006) type carried out using a ring with an inner diameter of 0.15 m. The BEST-steady algorithm, proposed by Bagarello et al. (2014), was used to analyze the cumulative infiltration curves in order to decrease the failure rate of the BEST algorithms (Di Prima et al., 2016). The in situ Ks,l at an intermediate spatial scale was estimated by a trench test (Blanco-Canqui et al., 2002) carried out on a monolith 50 cm wide, 68 cm long and 34.5 cm deep (the depth to substratum). Finally, the large spatial scale (hillslope-scale) Ks,lvalue was estimated from the outflow of a 8.5 m large drain and from the perched water table levels monitored in the hillslope, following the methodology of Brooks et al. (2004). Anisotropy was not detected, since the soil cube experiments did not revealed significant differences between Ks,v and Ks,l values. The differences between the Ks datasets measured by the cube and the BEST methods were not statistically significant at p = 0.05. These methods yielded Ks values 6.4 and 5.8 times lower than the hillslope-scale Ks,l, respectively. The Ks,l value obtained by the trench experiment in the soil monolith was 1440 mm h-1, which was only 1.5 times higher than the hillslope-scale Ks,l. Probably, the chosen size of soil monolith was sufficient to properly represent the spatial heterogeneity of the soil in the hillslope. This finding need to be confirmed by further trench tests in soil monoliths to be carried out in the studied hillslope. References Bagarello, V., Di Prima, S., Iovino, M., 2014. Comparing Alternative Algorithms to Analyze the Beerkan Infiltration Experiment. Soil Science Society of America Journal 78, 724. doi:10.2136/sssaj2013.06.0231 Bagarello, V., Sgroi, A., 2008. Testing Soil Encasing Materials for Measuring Hydraulic Conductivity of a Sandy-Loam Soil by the Cube Methods. Soil Science Society of America Journal 72, 1048. doi:10.2136/sssaj2007.0022 Blanco-Canqui, H., Gantzer, C.J., Anderson, S.H., Alberts, E.E., Ghidey, F., 2002. Saturated Hydraulic Conductivity and Its Impact on Simulated Runoff for Claypan Soils. Soil Science Society of America Journal 66, 1596. doi:10.2136/sssaj2002.1596 Brooks, E.S., Boll, J., McDaniel, P.A., 2004. A hillslope-scale experiment to measure lateral saturated hydraulic conductivity. Water Resour. Res. 40, W04208. doi:10.1029/2003WR002858 Castellini, M., Iovino, M., Pirastru, M., Niedda, M., Bagarello, V., 2016. Use of BEST Procedure to Assess Soil Physical Quality in the Baratz Lake Catchment (Sardinia, Italy). Soil Science Society of America Journal 0, 0. doi:10.2136/sssaj2015.11.0389 Di Prima, S., Lassabatere, L., Bagarello, V., Iovino, M., Angulo-Jaramillo, R., 2016. Testing a new automated single ring infiltrometer for Beerkan infiltration experiments. Geoderma 262, 20-34. doi:10.1016/j.geoderma.2015.08.006 Iovino, M., Castellini, M., Bagarello, V., Giordano, G., 2016. Using Static and Dynamic Indicators to Evaluate Soil Physical Quality in a Sicilian Area. Land Degrad. Develop. 27, 200-210. doi:10.1002/ldr.2263 Klute, A., Dirksen, C., 1986. Hydraulic Conductivity and Diffusivity: Laboratory Methods. Methods of Soil Analysis: Part 1—Physical and Mineralogical Methods sssabookseries, 687-734. doi:10.2136/sssabookser5.1.2ed.c28 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

Assessing soil quality and potential productivity - a basic approach to define and assess the marginality of land

NASA Astrophysics Data System (ADS)

Repmann, Frank; Gerwin, Werner; Freese, Dirk

2017-04-01

An ever growing demand for energy and the widely proposed switch from fossil fuels to more sustainable energy sources puts the cultivation and use of bioenergy plants into focus. However, bioenergy production on regular and fertile agricultural soils might conflict with the worldwide growing demand for food. To mitigate or omit this potential conflict, the use of low quality or marginal land for cultivation of bioenergy plants becomes favorable. Against this background the definition and assessment of land marginality and, respectively, the evaluation whether and to which extent specific areas are marginal and thus convenient for sustainable bioenergy production, becomes highly relevant. Within the framework of the EU funded Horizon 2020 project SEEMLA, we attempted to asses land marginality of designated test sites in the Ukraine, Greece and Germany by direct field survey. For that purpose, soil and site properties were investigated and evaluated by applying the Muencheberg Soil Quality Rating (SQR) method, developed at the Leibniz Centre for Agricultural Landscape Research (ZALF). The method deploys a comprehensive set of biogeophysical and chemical indicators to describe and finally evaluate the quality of the soil and site by a score ranging from 1 to 100 points. Field survey data were supported by additional laboratory tests on a representative set of soil samples. Practical field work and analysis of field and lab data from the investigated sites proved the applicability of the SQR method within the SEEMLA context. The SQR indices calculated from the field and lab data ranged from 2 to < 40 and clearly demonstrated the marginality of the investigated sites in the Ukraine, Greece and Germany, which differed considerably in respect to their characteristics. Correlating the site quality index to yield data reflecting yield estimations for common bioenergy plants such as willow (Salix sp.), black locust (Robinia pseudoacacia) and poplar (Populus sp.) cultivated at the respective test sites, revealed that SQR might additionally reflect the potential yield of the investigated sites.

Validated Test Method 5030C: Purge-and-Trap for Aqueous Samples

EPA Pesticide Factsheets

This method describes a purge-and-trap procedure for the analysis of volatile organic compoundsin aqueous samples & water miscible liquid samples. It also describes the analysis of high concentration soil and waste sample extracts prepared in Method 5035.

Hazardous impact and translocation of vanadium (V) species from soil to different vegetables and grasses grown in the vicinity of thermal power plant.

PubMed

Khan, Sumaira; Kazi, Tasneem Gul; Kolachi, Nida Fatima; Baig, Jameel Ahmed; Afridi, Hassan Imran; Shah, Abdul Qadir; Kumar, Sham; Shah, Faheem

2011-06-15

The distribution of vanadium (V) species in soil (test soil), vegetables and grasses, collected from the vicinity of a thermal power plant has been studied. For comparison purpose soil (control soil), same vegetable and grass samples were collected from agricultural land devoid of any industrial area. A simple and efficient ultrasonic assisted extraction method has been developed for the extraction of V(5+) species from soil, vegetable and grass samples using Na(2)CO(3) in the range of 0.1-0.5 mol/L. For comparison purpose same sub samples were also extracted by conventional heating method. The total and V species were determined by electrothermal atomic absorption spectrometry using different modifiers. The validity of V(5+) and V(4+) determination had been confirmed by the spike recovery and total amount of V by the analysis of CRM 1570 (spinach leave) and sub samples of agricultural soil. The concentration of total V was found in the range of 90-215 and 11.4-42.3 μg/g in test and control soil samples, respectively. The contents of V(5+) and total V in vegetables and grasses grown around the thermal power plant were found in the range of 2.9-5.25 and 8.74-14.9 μg/g, respectively, which were significantly higher than those values obtained from vegetables and fodders grown in non exposed agricultural site (P<0.01). Statistical evaluations indicate that the sum of concentrations of V(5+) and V(4+) species was not significantly different from total concentration of V in same sub samples of vegetable, grass and soil of both origins, at 95% level of confidence. Copyright © 2011 Elsevier B.V. All rights reserved.

Novel colorimetric method overcoming phosphorus interference during trace arsenic analysis in soil solution.

PubMed

Makris, Konstantinos C; Punamiya, Pravin; Sarkar, Dibyendu; Datta, Rupali

2008-02-01

A sensitive (method detection limit, 2.0 microg As L(-1)) colorimetric determination of trace As(v) and As(iii) concentrations in the presence of soluble phosphorus (P) concentrations in soil/water extracts is presented. The proposed method modifies the malachite green method (MG) originally developed for P in soil and water. Our method relies upon the finding that As(iii) and As(v) do not develop the green color during P analysis using the MG method. When an optimum concentration of ascorbic acid (AA) is added to a sample containing up to 15 times P > As (microM) concentrations, the final sample absorbance due to P will be equal to that of As(v) molecules. The soluble As concentration can then be quantified by the concentration difference between the mixed oxyanion (As + P) absorbance (proposed method) and the MG method absorbance that measures only P. Our method is miniaturized using a 96-well microplate UV-VIS reader that utilizes minute reagent and sample volumes (120 and 200 microL sample(-1), respectively), thus, minimizing waste and offering flexibility in the field. Our method was tested in a suite of As-contaminated soils that successfully measured both As and P in soil water extracts and total digests. Mean% As recoveries ranged between 84 and 117%, corroborating data obtained with high-resolution inductively-coupled plasma mass-spectrometry. The performance of the proposed colorimetric As method was unaffected by the presence of Cu, Zn, Pb, Ni, Fe, Al, Si, and Cr in both neutral and highly-acidic (ca. pH 2) soil extracts. Data from this study provide the proof of concept towards creating a field-deployable, portable As kit.

Deriving site-specific clean-up criteria to protect ecological receptors (plants and soil invertebrates) exposed to metal or metalloid soil contaminants via the direct contact exposure pathway

PubMed Central

Checkai, Ron; Van Genderen, Eric; Sousa, José Paulo; Stephenson, Gladys; Smolders, Erik

2014-01-01

Soil contaminant concentration limits for the protection of terrestrial plants and soil invertebrates are commonly based on thresholds derived using data from laboratory ecotoxicity tests. A comprehensive assessment has been made for the derivation of ecological soil screening levels (Eco-SSL) in the United States; however, these limits are conservative because of their focus on high bioavailability scenarios. Here, we explain and evaluate approaches to soil limit derivation taken by 4 jurisdictions, 2 of which allow for correction of data for factors affecting bioavailability among soils, and between spiked and field-contaminated soils (Registration Evaluation Authorisation and Restriction of Chemicals [REACH] Regulation, European Union [EU], and the National Environment Protection Council [NEPC], Australia). Scientifically advanced features from these methods have been integrated into a newly developed method for deriving soil clean-up values (SCVs) within the context of site-specific baseline ecological risk assessment. Resulting site-specific SCVs that account for bioavailability may permit a greater residual concentration in soil when compared to generic screening limit concentrations (e.g., Eco-SSL), while still affording acceptable protection. Two choices for selecting the level of protection are compared (i.e., allowing higher effect levels per species, or allowing a higher percentile of species that are potentially unprotected). Implementation of this new method is presented for the jurisdiction of the United States, with a focus on metal and metalloid contaminants; however, the new method can be used in any jurisdiction. A case study for molybdate shows the large effect of bioavailability corrections and smaller effects of protection level choices when deriving SCVs. Integr Environ Assess Manag 2014;10:346–357. PMID:24470189

Soil depth mapping using seismic surface waves: Evaluation on eroded loess covered hillslopes

NASA Astrophysics Data System (ADS)

Bernardie, Severine; Samyn, Kevin; Cerdan, Olivier; Grandjean, Gilles

2010-05-01

The purposes of the multidisciplinary DIGISOIL project are the integration and improvement of in situ and proximal technologies for the assessment of soil properties and soil degradation indicators. Foreseen developments concern sensor technologies, data processing and their integration to applications of (digital) soil mapping (DSM). Among available techniques, the seismic one is, in this study, particularly tested for characterising soil vulnerability to erosion. The spectral analysis of surface waves (SASW) method is an in situ seismic technique used for evaluation of the stiffnesses (G) and associated depth in layered systems. A profile of Rayleigh wave velocity versus frequency, i.e., the dispersion curve, is calculated from each recorded seismogram before to be inverted to obtain the vertical profile of shear wave velocity Vs. Then, the soil stiffness can easily be calculated from the shear velocity if the material density is estimated, and the soil stiffness as a function of depth can be obtained. This last information can be a good indicator to identify the soil bedrock limit. SASW measurements adapted to soil characterisation is proposed in the DIGISOIL project, as it produces in an easy and quick way a 2D map of the soil. This system was tested for the digital mapping of the depth of loamy material in a catchment of the European loess belt. The validation of this methodology has been performed with the realisation of several acquisitions along the seismic profiles: - Several boreholes were drilled until the bedrock, permitting to get the geological features of the soil and the depth of the bedrock; - Several laboratory measurements of various parameters were done on samples taken from the boreholes at various depths, such as dry density, solid density, and water content; - Dynamic penetration tests were also conducted along the seismic profile, until the bedrock is attained. Some empirical correlations between the parameters measured with laboratory tests, the qc obtained from the dynamic penetration tests and the Vs acquired from the SASW measurements permit to assess the accuracy of the procedure and to evaluate its limitations. The depth to bedrock determined by this procedure can then be combined with the soil erosion susceptibility to produce a risk map. This methodology will help to target measures within areas that show a reduced soil depth associated with a high soil erosion susceptibility.

Estimation of seismic quality factor: Artificial neural networks and current approaches

NASA Astrophysics Data System (ADS)

Yıldırım, Eray; Saatçılar, Ruhi; Ergintav, Semih

2017-01-01

The aims of this study are to estimate soil attenuation using alternatives to traditional methods, to compare results of using these methods, and to examine soil properties using the estimated results. The performances of all methods, amplitude decay, spectral ratio, Wiener filter, and artificial neural network (ANN) methods, are examined on field and synthetic data with noise and without noise. High-resolution seismic reflection field data from Yeniköy (Arnavutköy, İstanbul) was used as field data, and 424 estimations of Q values were made for each method (1,696 total). While statistical tests on synthetic and field data are quite close to the Q value estimation results of ANN, Wiener filter, and spectral ratio methods, the amplitude decay methods showed a higher estimation error. According to previous geological and geophysical studies in this area, the soil is water-saturated, quite weak, consisting of clay and sandy units, and, because of current and past landslides in the study area and its vicinity, researchers reported heterogeneity in the soil. Under the same physical conditions, Q value calculated on field data can be expected to be 7.9 and 13.6. ANN models with various structures, training algorithm, input, and number of neurons are investigated. A total of 480 ANN models were generated consisting of 60 models for noise-free synthetic data, 360 models for different noise content synthetic data and 60 models to apply to the data collected in the field. The models were tested to determine the most appropriate structure and training algorithm. In the final ANN, the input vectors consisted of the difference of the width, energy, and distance of seismic traces, and the output was Q value. Success rate of both ANN methods with noise-free and noisy synthetic data were higher than the other three methods. Also according to the statistical tests on estimated Q value from field data, the method showed results that are more suitable. The Q value can be estimated practically and quickly by processing the traces with the recommended ANN model. Consequently, the ANN method could be used for estimating Q value from seismic data.

Applicability of ELISA-based Determination of Pesticides for Groundwater Quality Monitoring

NASA Astrophysics Data System (ADS)

Tsuchihara, Takeo; Yoshimoto, Shuhei; Ishida, Satoshi; Imaizumi, Masayuki

The principals and procedures of ELISA (Enzyme-linked Immunosorbent Assay)-based determination of pesticides (Fenitrothion) in environmental samples were reviewed, and the applicability of the ELISA method for groundwater quality monitoring were validated through the experimental tracer tests in soil columns and the field test in Okinoerabu Island. The test results showed that the ELISA method could be useful not only for screening but also for quantitative analysis of pesticides. In the experimental tracer tests in soil columns, the retardation of pesticides leaching compared with conservative tracers were observed. In the field test, the contamination of the pesticide was detected in groundwater samples in Okinoerabu Island, even though the targeted pesticide was considered to be applied to the upland field 4 months ago. In order to investigate the transport and fate of pesticides in groundwater taking into account retardation from the field to groundwater table and the residue in groundwater, continuous observations of pesticides in groundwater are in a strong need, and the ELISA method is applicable to the long-term quality groundwater monitoring.

Minute tubular forms in soil

NASA Technical Reports Server (NTRS)

Casida, L. E., Jr.; Liu, K.-C.

1979-01-01

Large numbers of long, straight, flattened structures were observed during an electron-microscope study of bacteriophage in aqueous extracts. These structures were called tubules and ranged in width from 10 to 50 nm. Materials and methods were discussed relative to extraction of tubules from soil, electron microscopy, quantitation of tubules in filtrate suspension, tests performed on tubules, plaque formation, and nutrient amendments. It is found that all of the tubules recovered from soil are broken at one or both ends. They are present in surface soils but not in a subsurface sample. Their numbers decrease during bacterial multiplication in soil or broth-containing soil. The tubules appear to be composed of protein that could be disintegrated to liberate nonprotein fibers. A possible clue to the nature of the tubules is their apparent relation to soil bacteria.

Quantifying statistical relationships between commonly used in vitro models for estimating lead bioaccessibility.

PubMed

Yan, Kaihong; Dong, Zhaomin; Liu, Yanju; Naidu, Ravi

2016-04-01

Bioaccessibility to assess potential risks resulting from exposure to Pb-contaminated soils is commonly estimated using various in vitro methods. However, existing in vitro methods yield different results depending on the composition of the extractant as well as the contaminated soils. For this reason, the relationships between the five commonly used in vitro methods, the Relative Bioavailability Leaching Procedure (RBALP), the unified BioAccessibility Research Group Europe (BARGE) method (UBM), the Solubility Bioaccessibility Research Consortium assay (SBRC), a Physiologically Based Extraction Test (PBET), and the in vitro Digestion Model (RIVM) were quantified statistically using 10 soils from long-term Pb-contaminated mining and smelter sites located in Western Australia and South Australia. For all 10 soils, the measured Pb bioaccessibility regarding all in vitro methods varied from 1.9 to 106% for gastric phase, which is higher than that for intestinal phase: 0.2 ∼ 78.6%. The variations in Pb bioaccessibility depend on the in vitro models being used, suggesting that the method chosen for bioaccessibility assessment must be validated against in vivo studies prior to use for predicting risk. Regression studies between RBALP and SRBC, RBALP and RIVM (0.06) (0.06 g of soil in each tube, S:L ratios for gastric phase and intestinal phase are 1:375 and 1:958, respectively) showed that Pb bioaccessibility based on the three methods were comparable. Meanwhile, the slopes between RBALP and UBM, RBALP and RIVM (0.6) (0.6 g soil in each tube, S:L ratios for gastric phase and intestinal phase are 1:37.5 and 1:96, respectively) were 1.21 and 1.02, respectively. The findings presented in this study could help standardize in vitro bioaccessibility measurements and provide a scientific basis for further relating Pb bioavailability and soil properties.

New Materials for the Undergraduate Classroom to Build Pre-Service Teachers' NGSS Skills and Knowledge

NASA Astrophysics Data System (ADS)

Egger, A. E.; Awad, A. A.; Baldwin, K. A.; Birnbaum, S. J.; Bruckner, M. Z.; DeBari, S. M.; Dechaine, J.; Ebert, J. R.; Gray, K. R.; Hauge, R.; Linneman, S. R.; Monet, J.; Thomas, J.; Varrella, G.

2014-12-01

As part of InTeGrate, teams of 3 instructors at 3 different institutions developed modules that help prepare pre-service teachers to teach Earth science aligned with the NGSS. Modules were evaluated against a rubric, which addresses InTeGrate's five guiding principles, learning objectives and outcomes, assessment and measurement, resources and materials, instructional strategies and alignment. As all modules must address one or more Earth-related grand challenge facing society, develop student ability to address interdisciplinary problems, improve student understanding of the methods of geoscience, use authentic geoscience data, and incorporate systems thinking, they align well with the NGSS. Once modules passed the rubric, they were tested by the authors in their classrooms. Testing included pre- and post-assessment of geoscience literacy and assessment of student learning towards the module goal; materials were revised based on the results of testing. In "Exploring Geoscience Methods with Secondary Education Students," pre-service science teachers compare geoscientific thinking with the classic (experimental) scientific method, investigate global climate change and its impacts on human systems, and prepare an interdisciplinary lesson plan that addresses geoscience methods in context of a socioscientific issue. In "Soils and Society," pre-service elementary teachers explore societal issues where soil is important, develop skills to describe and test soil properties, and create a standards-based Soils and Society Kit that consists of lessons and supporting materials to teach K-8 students about a soil-and-society issue. In "Interactions between Water, Earth's Surface, and Human Activity," students explore the effects of running water on shaping Earth's surface both over geologic time and through short-term flooding events, and produce a brochure to inform citizens of the impact of living near a river. The modules are freely available at http://serc.carleton.edu/integrate/teaching_materials/modules_courses.html and include Instructor Stories, where each author describes how they adapted the module to their teaching environment. The goal of showing different implementations of the materialst is to facilitate adoption and adaption beyond the team of authors.

Evaluation of bearing capacity of piles from cone penetration test data : technical summary.

DOT National Transportation Integrated Search

1999-11-01

Among the different in situ tests, cone penetration test (CPT) is considered the most frequently used method for characterization of geomedia. Due to the soft nature of soil deposits in Louisiana, the CPT is considered a perfect tool for characteriza...

40 CFR 796.2750 - Sediment and soil adsorption isotherm.

Code of Federal Regulations, 2014 CFR

2014-07-01

... are highly reproducible. The test provides excellent quantitative data readily amenable to statistical... combination of methods suitable for the identification and quantitative detection of the parent test chemical... quantitative analysis of the parent chemical. (3) Amount of parent test chemical applied, the amount recovered...

40 CFR 796.2750 - Sediment and soil adsorption isotherm.

Code of Federal Regulations, 2013 CFR

2013-07-01

... highly reproducible. The test provides excellent quantitative data readily amenable to statistical... combination of methods suitable for the identification and quantitative detection of the parent test chemical... quantitative analysis of the parent chemical. (3) Amount of parent test chemical applied, the amount recovered...

40 CFR 796.2750 - Sediment and soil adsorption isotherm.

Code of Federal Regulations, 2012 CFR

2012-07-01

... highly reproducible. The test provides excellent quantitative data readily amenable to statistical... combination of methods suitable for the identification and quantitative detection of the parent test chemical... quantitative analysis of the parent chemical. (3) Amount of parent test chemical applied, the amount recovered...

Remote sensing as a tool for estimating soil erosion potential

NASA Technical Reports Server (NTRS)

Morris-Jones, D. R.; Morgan, K. M.; Kiefer, R. W.

1979-01-01

The Universal Soil Loss Equation is a frequently used methodology for estimating soil erosion potential. The Universal Soil Loss Equation requires a variety of types of geographic information (e.g. topographic slope, soil erodibility, land use, crop type, and soil conservation practice) in order to function. This information is traditionally gathered from topographic maps, soil surveys, field surveys, and interviews with farmers. Remote sensing data sources and interpretation techniques provide an alternative method for collecting information regarding land use, crop type, and soil conservation practice. Airphoto interpretation techniques and medium altitude, multi-date color and color infrared positive transparencies (70mm) were utilized in this study to determine their effectiveness for gathering the desired land use/land cover data. Successful results were obtained within the test site, a 6136 hectare watershed in Dane County, Wisconsin.

Design and Test of an Improved Crashworthiness Small Composite Airframe

NASA Technical Reports Server (NTRS)

Terry, James E.; Hooper, Steven J.; Nicholson, Mark

2002-01-01

The purpose of this small business innovative research (SBIR) program was to evaluate the feasibility of developing small composite airplanes with improved crashworthiness. A combination of analysis and half scale component tests were used to develop an energy absorbing airframe. Four full scale crash tests were conducted at the NASA Impact Dynamics Research Facility, two on a hard surface and two onto soft soil, replicating earlier NASA tests of production general aviation airplanes. Several seat designs and restraint systems including both an air bag and load limiting shoulder harnesses were tested. Tests showed that occupant loads were within survivable limits with the improved structural design and the proper combination of seats and restraint systems. There was no loss of cabin volume during the events. The analysis method developed provided design guidance but time did not allow extending the analysis to soft soil impact. This project demonstrated that survivability improvements are possible with modest weight penalties. The design methods can be readily applied by airplane designers using the examples in this report.

Polycyclic aromatic hydrocarbons bioavailability in industrial and agricultural soils: Linking SPME and Tenax extraction with bioassays.

PubMed

Guo, Meixia; Gong, Zongqiang; Li, Xiaojun; Allinson, Graeme; Rookes, James; Cahill, David

2017-06-01

The aims of this study were to evaluate the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in industrial and agricultural soils using chemical methods and a bioassay, and to study the relationships between the methods. This was conducted by comparing the quantities of PAHs extracted from two manufactured gas plant (MGP) soils and an agricultural soil with low level contamination by solid-phase micro-extraction (SPME) and Tenax-TA extraction with the quantities taken up by the earthworm (Eisenia fetida). In addition, a biodegradation experiment was conducted on one MGP soil (MGP-A) to clarify the relationship between PAH removal by biodegradation and the variation in PAH concentrations in soil pore water. Results demonstrated that the earthworm bioassay could not be used to examine PAH bioavailability in the tested MGP soils; which was the case even in the diluted MGP-A soils after biodegradation. However, the bioassay was successfully applied to the agricultural soil. These results suggest that earthworms can only be used for bioassays in soils with low toxicity. In general, rapidly desorbing concentrations extracted by Tenax-TA could predict PAH concentrations accumulated in earthworms (R 2 =0.66), while SPME underestimated earthworm concentrations by a factor of 2.5. Both SPME and Tenax extraction can provide a useful tool to predict PAH bioavailability for earthworms, but Tenax-TA extraction was proven to be a more sensitive and precise method than SPME for the prediction of earthworm exposure in the agricultural soil. Copyright © 2017. Published by Elsevier Inc.

Influence of mycorrhizal source and seeding methods on native grass species grown in soils from a disturbed site

Treesearch

Todd R. Caplan; Heather A. Pratt; Samuel R. Loftin

1999-01-01

Mycorrhizal fungi are crucial elements in native plant communities and restoring these fungi to disturbed sites is known to improve revegetation success. We tested the seedball method of plant dispersal for restoration of plants and mycorrhizal fungi to disturbed ecosystems. We tested the seedball method with a native mycorrhizal fungi inoculum, and a commercial...

Correcting the influence of vegetation on surface soil moisture indices by using hyperspectral artificial 3D-canopy models

NASA Astrophysics Data System (ADS)

Spengler, D.; Kuester, T.; Frick, A.; Scheffler, D.; Kaufmann, H.

2013-10-01

Surface soil moisture content is one of the key variables used for many applications especially in hydrology, meteorology and agriculture. Hyperspectral remote sensing provides effective methodologies for mapping soil moisture content over a broad area by different indices such as NSMI [1,2] and SMGM [3]. Both indices can achieve a high accuracy for non-vegetation influenced soil samples, but their accuracy is limited in case of the presence of vegetation. Since, the increase of the vegetation cover leads to non-linear variations of the indices. In this study a new methodology for moisture indices correcting the influence of vegetation is presented consisting of several processing steps. First, hyperspectral reflectance data are classified in terms of crop type and growth stage. Second, based on these parameters 3D plant models from a database used to simulate typical canopy reflectance considering variations in the canopy structure (e.g. plant density and distribution) and the soil moisture content for actual solar illumination and sensor viewing angles. Third, a vegetation correction function is developed, based on the calculated soil moisture indices and vegetation indices of the simulated canopy reflectance data. Finally this function is applied on hyperspectral image data. The method is tested on two hyperspectral image data sets of the AISA DUAL at the test site Fichtwald in Germany. The results show a significant improvements compared to solely use of NSMI index. Up to a vegetation cover of 75 % the correction function minimise the influences of vegetation cover significantly. If the vegetation is denser the method leads to inadequate quality to predict the soil moisture content. In summary it can be said that applying the method on weakly to moderately overgrown with vegetation locations enables a significant improvement in the quantification of soil moisture and thus greatly expands the scope of NSMI.

Sprinkle Test by Phoenix Robotic Arm Movie

NASA Image and Video Library

2008-06-10

NASA Phoenix Mars Lander used its Robotic Arm during the mission 15th Martian day since landing June 9, 2008 to test a prinkle method for delivering small samples of soil to instruments on the lander deck.

Seismic behavior of breakwaters on complex ground by numerical tests: Liquefaction and post liquefaction ground settlements

NASA Astrophysics Data System (ADS)

Gu, Linlin; Zhang, Feng; Bao, Xiaohua; Shi, Zhenming; Ye, Guanlin; Ling, Xianzhang

2018-04-01

A large number of breakwaters have been constructed along coasts to protect humans and infrastructures from tsunamis. There is a risk that foundation soils of these structures may liquefy, or partially liquefy during the earthquake preceding a tsunami, which would greatly reduce the structures' capacity to resist the tsunami. It is necessary to consider not only the soil's liquefaction behavior due to earthquake motions but also its post-liquefaction behavior because this behavior will affect the breakwater's capacity to resist an incoming tsunami. In this study, numerical tests based on a sophisticated constitutive model and a soil-water coupled finite element method are used to predict the mechanical behavior of breakwaters and the surrounding soils. Two real breakwaters subjected to two different seismic excitations are examined through numerical simulation. The simulation results show that, earthquakes affect not only the immediate behavior of breakwaters and the surrounding soils but also their long-term settlements due to post-earthquake consolidation. A soil profile with thick clayey layers beneath liquefied soil is more vulnerable to tsunami than a soil profile with only sandy layers. Therefore, quantitatively evaluating the seismic behavior of breakwaters and surrounding soils is important for the design of breakwater structures to resist tsunamis.

Direct Detection of Soil-Bound Prions

PubMed Central

Genovesi, Sacha; Leita, Liviana; Sequi, Paolo; Andrighetto, Igino; Sorgato, M. Catia; Bertoli, Alessandro

2007-01-01

Scrapie and chronic wasting disease are contagious prion diseases affecting sheep and cervids, respectively. Studies have indicated that horizontal transmission is important in sustaining these epidemics, and that environmental contamination plays an important role in this. In the perspective of detecting prions in soil samples from the field by more direct methods than animal-based bioassays, we have developed a novel immuno-based approach that visualises in situ the major component (PrPSc) of prions sorbed onto agricultural soil particles. Importantly, the protocol needs no extraction of the protein from soil. Using a cell-based assay of infectivity, we also report that samples of agricultural soil, or quartz sand, acquire prion infectivity after exposure to whole brain homogenates from prion-infected mice. Our data provide further support to the notion that prion-exposed soils retain infectivity, as recently determined in Syrian hamsters intracerebrally or orally challanged with contaminated soils. The cell approach of the potential infectivity of contaminated soil is faster and cheaper than classical animal-based bioassays. Although it suffers from limitations, e.g. it can currently test only a few mouse prion strains, the cell model can nevertheless be applied in its present form to understand how soil composition influences infectivity, and to test prion-inactivating procedures. PMID:17957252

A universal method to assess the potential of phosphorus loss from soil to aquatic ecosystems.

PubMed

Pöthig, Rosemarie; Behrendt, Horst; Opitz, Dieter; Furrer, Gerhard

2010-02-01

Phosphorus loss from terrestrial to the aquatic ecosystems contributes to eutrophication of surface waters. To maintain the world's vital freshwater ecosystems, the reduction of eutrophication is crucial. This needs the prevention of overfertilization of agricultural soils with phosphorus. However, the methods of risk assessment for the P loss potential from soils lack uniformity and are difficult for routine analysis. Therefore, the efficient detection of areas with a high risk of P loss requires a simple and universal soil test method that is cost effective and applicable in both industrialized and developing countries. Soils from areas which varied highly in land use and soil type were investigated regarding the degree of P saturation (DPS) as well as the equilibrium P concentration (EPC(0)) and water-soluble P (WSP) as indicators for the potential of P loss. The parameters DPS and EPC(0) were determined from P sorption isotherms. Our investigation of more than 400 soil samples revealed coherent relationships between DPS and EPC(0) as well as WSP. The complex parameter DPS, characterizing the actual P status of soil, is accessible from a simple standard measurement of WSP based on the equation [Formula: see text]. The parameter WSP in this equation is a function of remaining phosphorous sorption capacity/total accumulated phosphorous (SP/TP). This quotient is independent of soil type due to the mutual compensation of the factors SP and TP. Thus, the relationship between DPS and WSP is also independent of soil type. The degree of P saturation, which reflects the actual state of P fertilization of soil, can be calculated from the easily accessible parameter WSP. Due to the independence from soil type and land use, the relation is valid for all soils. Values of WSP, which exceed 5 mg P/kg soil, signalize a P saturation between 70% and 80% and thus a high risk of P loss from soil. These results reveal a new approach of risk assessment for P loss from soils to surface and ground waters. The consequent application of this method may globally help to save the vital resources of our terrestrial and aquatic ecosystems.

Bioaccessibility tests accurately estimate bioavailability of lead to quail.

PubMed

Beyer, W Nelson; Basta, Nicholas T; Chaney, Rufus L; Henry, Paula F P; Mosby, David E; Rattner, Barnett A; Scheckel, Kirk G; Sprague, Daniel T; Weber, John S

2016-09-01

Hazards of soil-borne lead (Pb) to wild birds may be more accurately quantified if the bioavailability of that Pb is known. To better understand the bioavailability of Pb to birds, the authors measured blood Pb concentrations in Japanese quail (Coturnix japonica) fed diets containing Pb-contaminated soils. Relative bioavailabilities were expressed by comparison with blood Pb concentrations in quail fed a Pb acetate reference diet. Diets containing soil from 5 Pb-contaminated Superfund sites had relative bioavailabilities from 33% to 63%, with a mean of approximately 50%. Treatment of 2 of the soils with phosphorus (P) significantly reduced the bioavailability of Pb. Bioaccessibility of Pb in the test soils was then measured in 6 in vitro tests and regressed on bioavailability: the relative bioavailability leaching procedure at pH 1.5, the same test conducted at pH 2.5, the Ohio State University in vitro gastrointestinal method, the urban soil bioaccessible lead test, the modified physiologically based extraction test, and the waterfowl physiologically based extraction test. All regressions had positive slopes. Based on criteria of slope and coefficient of determination, the relative bioavailability leaching procedure at pH 2.5 and Ohio State University in vitro gastrointestinal tests performed very well. Speciation by X-ray absorption spectroscopy demonstrated that, on average, most of the Pb in the sampled soils was sorbed to minerals (30%), bound to organic matter (24%), or present as Pb sulfate (18%). Additional Pb was associated with P (chloropyromorphite, hydroxypyromorphite, and tertiary Pb phosphate) and with Pb carbonates, leadhillite (a lead sulfate carbonate hydroxide), and Pb sulfide. The formation of chloropyromorphite reduced the bioavailability of Pb, and the amendment of Pb-contaminated soils with P may be a thermodynamically favored means to sequester Pb. Environ Toxicol Chem 2016;35:2311-2319. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America.

Measuring organic matter in Everglades wetlands and the Everglades Agricultural Area

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

Wright, Alan L.; Hanlon, Edward A.

Here, organic matter is a complex material that represents the long-term decay products from plants and other organisms in the soil. When organic matter is allowed to build up in a soil, the soil color at the surface usually turns a darker color, often with a red or brown hue. Typically in Florida mineral soils, organic matter content is quite low, within the range of 1 to 5%. However, in some soils that remain flooded for most of the year, organic matter can build up with time and actually become the soil. Such is the case for the organic soils,more » or histosols, found in southern Florida. These organic soils comprise much of the Water Conservation Areas, Everglades National Park (ENP), Big Cypress Basin, and the Everglades Agricultural Area (EAA). It is important to document organic matter accumulation in the Everglades to gauge the effectiveness of wetland creation and succession. For the EAA, the drained soils lose organic matter due to oxidation, so measurement of the organic matter content of these soils over the course of time indicates the oxidation potential and mineral incorporation from bedrock. Due to the wide diversity of soil types and methods of measuring soil organic matter, there is a need to devise a more universal method applicable to many types of histosols in south Florida. The intent of this publication is: 1.To describe a simple laboratory method for determining the organic matter content of the organic soils of southern Florida and demonstrate the importance of using this new procedure for improved accuracy and precision; 2.To utilize this updated laboratory procedure for field sites across Everglades wetlands and the EAA; and 3. To recommend this procedure be used by growers, state and federal agencies, and university and agency researchers dealing with the management of organic soils in southern Florida. Growers can use this improvement to organic matter measurement to keep lab testing costs low while getting a better, more quantitative estimate of organic carbon (organic matter) for decisions regarding pesticide applications and estimated contribution of nutrients released from the organic matter in their fields. Restoration efforts in the Everglades wetlands can be better documented with the lower cost, but now equally as useful, LOI test for organic carbon. Improvements to soil organic matter coupled with other measurements of biological health of the system can be documented with less work using the adjusted LOI calculations.« less

Predicting arsenic bioavailability to hyperaccumulator Pteris vittata in arsenic-contaminated soils.

PubMed

Gonzaga, Maria Isidória Silva; Ma, Lena Q; Pacheco, Edson Patto; dos Santos, Wallace Melo

2012-12-01

Using chemical extraction to evaluate plant arsenic availability in contaminated soils is important to estimate the time frame for site cleanup during phytoremediation. It is also of great value to assess As mobility in soil and its risk in environmental contamination. In this study, four conventional chemical extraction methods (water, ammonium sulfate, ammonium phosphate, and Mehlich III) and a new root-exudate based method were used to evaluate As extractability and to correlate it with As accumulation in P. vittata growing in five As-contaminated soils under greenhouse condition. The relationship between different soil properties, and As extractability and plant As accumulation was also investigated. Arsenic extractability was 4.6%, 7.0%, 18%, 21%, and 46% for water, ammonium sulfate, organic acids, ammonium phosphate, and Mehlich III, respectively. Root exudate (organic acids) solution was suitable for assessing As bioavailability (81%) in the soils while Mehlich III (31%) overestimated the amount of As taken up by plants. Soil organic matter, P and Mg concentrations were positively correlated to plant As accumulation whereas Ca concentration was negatively correlated. Further investigation is needed on the effect of Ca and Mg on As uptake by P. vittata. Moreover, additional As contaminated soils with different properties should be tested.

Assessment of ambient background concentrations of elements in soil using combined survey and open-source data.

PubMed

Mikkonen, Hannah G; Clarke, Bradley O; Dasika, Raghava; Wallis, Christian J; Reichman, Suzie M

2017-02-15

Understanding ambient background concentrations in soil, at a local scale, is an essential part of environmental risk assessment. Where high resolution geochemical soil surveys have not been undertaken, soil data from alternative sources, such as environmental site assessment reports, can be used to support an understanding of ambient background conditions. Concentrations of metals/metalloids (As, Mn, Ni, Pb and Zn) were extracted from open-source environmental site assessment reports, for soils derived from the Newer Volcanics basalt, of Melbourne, Victoria, Australia. A manual screening method was applied to remove samples that were indicated to be contaminated by point sources and hence not representative of ambient background conditions. The manual screening approach was validated by comparison to data from a targeted background soil survey. Statistical methods for exclusion of contaminated samples from background soil datasets were compared to the manual screening method. The statistical methods tested included the Median plus Two Median Absolute Deviations, the upper whisker of a normal and log transformed Tukey boxplot, the point of inflection on a cumulative frequency plot and the 95th percentile. We have demonstrated that where anomalous sample results cannot be screened using site information, the Median plus Two Median Absolute Deviations is a conservative method for derivation of ambient background upper concentration limits (i.e. expected maximums). The upper whisker of a boxplot and the point of inflection on a cumulative frequency plot, were also considered adequate methods for deriving ambient background upper concentration limits, where the percentage of contaminated samples is <25%. Median ambient background concentrations of metals/metalloids in the Newer Volcanic soils of Melbourne were comparable to ambient background concentrations in Europe and the United States, except for Ni, which was naturally enriched in the basalt-derived soils of Melbourne. Copyright © 2016 Elsevier B.V. All rights reserved.

An improved method for field extraction and laboratory analysis of large, intact soil cores

USGS Publications Warehouse

Tindall, J.A.; Hemmen, K.; Dowd, J.F.

1992-01-01

Various methods have been proposed for the extraction of large, undisturbed soil cores and for subsequent analysis of fluid movement within the cores. The major problems associated with these methods are expense, cumbersome field extraction, and inadequate simulation of unsaturated flow conditions. A field and laboratory procedure is presented that is economical, convenient, and simulates unsaturated and saturated flow without interface flow problems and can be used on a variety of soil types. In the field, a stainless steel core barrel is hydraulically pressed into the soil (30-cm diam. and 38 cm high), the barrel and core are extracted from the soil, and after the barrel is removed from the core, the core is then wrapped securely with flexible sheet metal and a stainless mesh screen is attached to the bottom of the core for support. In the laboratory the soil core is set atop a porous ceramic plate over which a soil-diatomaceous earth slurry has been poured to assure good contact between plate and core. A cardboard cylinder (mold) is fastened around the core and the empty space filled with paraffin wax. Soil cores were tested under saturated and unsaturated conditions using a hanging water column for potentials ???0. Breakthrough curves indicated that no interface flow occurred along the edge of the core. This procedure proved to be reliable for field extraction of large, intact soil cores and for laboratory analysis of solute transport.

Automatic flow-through dynamic extraction: A fast tool to evaluate char-based remediation of multi-element contaminated mine soils.

PubMed

Rosende, María; Beesley, Luke; Moreno-Jimenez, Eduardo; Miró, Manuel

2016-02-01

An automatic in-vitro bioaccessibility test based upon dynamic microcolumn extraction in a programmable flow setup is herein proposed as a screening tool to evaluate bio-char based remediation of mine soils contaminated with trace elements as a compelling alternative to conventional phyto-availability tests. The feasibility of the proposed system was evaluated by extracting the readily bioaccessible pools of As, Pb and Zn in two contaminated mine soils before and after the addition of two biochars (9% (w:w)) of diverse source origin (pine and olive). Bioaccessible fractions under worst-case scenarios were measured using 0.001 mol L(-1) CaCl2 as extractant for mimicking plant uptake, and analysis of the extracts by inductively coupled optical emission spectrometry. The t-test of comparison of means revealed an efficient metal (mostly Pb and Zn) immobilization by the action of olive pruning-based biochar against the bare (control) soil at the 0.05 significance level. In-vitro flow-through bioaccessibility tests are compared for the first time with in-vivo phyto-toxicity assays in a microcosm soil study. By assessing seed germination and shoot elongation of Lolium perenne in contaminated soils with and without biochar amendments the dynamic flow-based bioaccessibility data proved to be in good agreement with the phyto-availability tests. Experimental results indicate that the dynamic extraction method is a viable and economical in-vitro tool in risk assessment explorations to evaluate the feasibility of a given biochar amendment for revegetation and remediation of metal contaminated soils in a mere 10 min against 4 days in case of phyto-toxicity assays. Copyright © 2015 Elsevier B.V. All rights reserved.

The Ultimate Pile Bearing Capacity from Conventional and Spectral Analysis of Surface Wave (SASW) Measurements

NASA Astrophysics Data System (ADS)

Faizah Bawadi, Nor; Anuar, Shamilah; Rahim, Mustaqqim A.; Mansor, A. Faizal

2018-03-01

A conventional and seismic method for determining the ultimate pile bearing capacity was proposed and compared. The Spectral Analysis of Surface Wave (SASW) method is one of the non-destructive seismic techniques that do not require drilling and sampling of soils, was used in the determination of shear wave velocity (Vs) and damping (D) profile of soil. The soil strength was found to be directly proportional to the Vs and its value has been successfully applied to obtain shallow bearing capacity empirically. A method is proposed in this study to determine the pile bearing capacity using Vs and D measurements for the design of pile and also as an alternative method to verify the bearing capacity from the other conventional methods of evaluation. The objectives of this study are to determine Vs and D profile through frequency response data from SASW measurements and to compare pile bearing capacities obtained from the method carried out and conventional methods. All SASW test arrays were conducted near the borehole and location of conventional pile load tests. In obtaining skin and end bearing pile resistance, the Hardin and Drnevich equation has been used with reference strains obtained from the method proposed by Abbiss. Back analysis results of pile bearing capacities from SASW were found to be 18981 kN and 4947 kN compared to 18014 kN and 4633 kN of IPLT with differences of 5% and 6% for Damansara and Kuala Lumpur test sites, respectively. The results of this study indicate that the seismic method proposed in this study has the potential to be used in estimating the pile bearing capacity.

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

PubMed

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

2015-03-19

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

Comparison of whole-cell fatty acid (MIDI) or phospholipid fatty acid (PLFA) extractants as biomarkers to profile soil microbial communities.

PubMed

Fernandes, Marcelo F; Saxena, Jyotisna; Dick, Richard P

2013-07-01

The whole-cell lipid extraction to profile microbial communities on soils using fatty acid (FA) biomarkers is commonly done with the two extractants associated with the phospholipid fatty acid (PLFA) or Microbial IDentification Inc. (MIDI) methods. These extractants have very different chemistry and lipid separation procedures, but often shown a similar ability to discriminate soils from various management and vegetation systems. However, the mechanism and the chemistry of the exact suite of FAs extracted by these two methods are poorly understood. Therefore, the objective was to qualitatively and quantitatively compare the MIDI and PLFA microbial profiling methods for detecting microbial community shifts due to soil type or management. Twenty-nine soil samples were collected from a wide range of soil types across Oregon and extracted FAs by each method were analyzed by gas chromatography (GC) and GC-mass spectrometry. Unlike PLFA profiles, which were highly related to microbial FAs, the overall MIDI-FA profiles were highly related to the plant-derived FAs. Plant-associated compounds were quantitatively related to particulate organic matter (POM) and qualitatively related to the standing vegetation at sampling. These FAs were negatively correlated to respiration rate normalized to POM (RespPOM), which increased in systems under more intensive management. A strong negative correlation was found between MIDI-FA to PLFA ratios and total organic carbon (TOC). When the reagents used in MIDI procedure were tested for the limited recovery of MIDI-FAs from soil with high organic matter, the recovery of MIDI-FA microbial signatures sharply decreased with increasing ratios of soil to extractant. Hence, the MIDI method should be used with great caution for interpreting changes in FA profiles due to shifts in microbial communities.

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

PubMed Central

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

2015-01-01

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

A novel method for rapidly isolating microbes that suppress soil-borne phytopathogens

NASA Astrophysics Data System (ADS)

Cooper, Sarah; Agnew, Linda; Pereg, Lily

2016-04-01

Seedling establishment faces a large number of challenges related to soil physical properties as well as to fungal root diseases. It is extremely difficult to eliminate fungal pathogens from soils where their populations are established due to the persistent nature of their spores and since fumigation of resident fungi is very ineffective in clay-containing soils. Therefore it is necessary to find ways to overcome disease in areas where the soils are infected with fungal phytopathogens. The phenomenon of disease suppressive soils, where the pathogen is present but no disease observed, suggests that microbial antagonism in the soil may lead to the suppression of the growth of fungal pathogens. There are also cases in the literature where soil microorganisms were isolated that suppress the growth of phytopathogens. Antibiosis is one of the most important mechanisms responsible for fungal antagonism, with some significant antifungal compounds involved including antibiotics, volatile organic compounds, hydrogen cyanide and lytic enzymes. Isolation of pathogen-suppressive microorganisms from the soil is time consuming and tedious. We established a simple method for direct isolation of soil microbes (bacteria and fungi) that suppress fungal phytopathogens as well as procedures for confirmation of disease suppression. We will discuss such methods, which were so far tested with the cotton fungal pathogens Thielaviopsis basicola, Verticillium dahliae and Fusarium oxysporum and Verticillium fungicola. We have isolated a diversity of T. basicola-suppressive fungi and bacteria from two vastly different soil types. Identification of the antagonistic isolates revealed that they are a diverse lot, some belong to groups known to be suppressive of a wide range of fungal pathogens, endorsing the power of this technique to rapidly and directly isolate soil-borne microbes antagonistic to a wide variety of fungal pathogens.

Predicting soil quality indices with near infrared analysis in a wildfire chronosequence.

PubMed

Cécillon, Lauric; Cassagne, Nathalie; Czarnes, Sonia; Gros, Raphaël; Vennetier, Michel; Brun, Jean-Jacques

2009-01-15

We investigated the power of near infrared (NIR) analysis for the quantitative assessment of soil quality in a wildfire chronosequence. The effect of wildfire disturbance and soil engineering activity of earthworms on soil organic matter quality was first assessed with principal component analysis of NIR spectra. Three soil quality indices were further calculated using an adaptation of the method proposed by Velasquez et al. [Velasquez, E., Lavelle, P., Andrade, M. GISQ, a multifunctional indicator of soil quality. Soil Biol Biochem 2007; 39: 3066-3080.], each one addressing an ecosystem service provided by soils: organic matter storage, nutrient supply and biological activity. Partial least squares regression models were developed to test the predicting ability of NIR analysis for these soil quality indices. All models reached coefficients of determination above 0.90 and ratios of performance to deviation above 2.8. This finding provides new opportunities for the monitoring of soil quality, using NIR scanning of soil samples.

Systematic Approach to Identifying Deeply Buried Archeological Deposits

DOT National Transportation Integrated Search

2018-02-01

Traditional methods used to discover archeological sites include pedestrian surface surveys and relatively shallow hand-dug shovel or soil core testing. While these methods are appropriate for locating surface and near-surface sites on ridges, hillto...

Use of bioassays for testing soils and/or sediments contaminated by mining activities

NASA Astrophysics Data System (ADS)

Pérez-Sirvent, C.; Martínez-Sánchez, M. J.; García-Lorenzo, M. L.; Molina, J.

2009-04-01

Ecotoxicity tests measure the bioavailability of the contaminants and the effects of the chemically not measured toxic compounds on the members of the soil community. Therefore, ecotoxicological testing may be a useful approach for assessing the toxicity as a complement to chemical analysis. They are solid phase tests based on terrestrial methods and tests performed on water extracts using aquatic test protocols. The extent and degree of heavy metal contamination around mines may vary depending on geochemical characteristics, the mineralization of tailings, physico-chemical conditions and the processes used to extract metals. Portman Bay was subject to mining from the time of the Roman Empire to 1991 when the activity ceased. Since 1957, the wastes from mining operations were discharged directly into the sea. These wastes mainly consisted of clay, quartz, siderite, magnetite, remains of sphalerite, pyrite and galena and residues of the chemical reagents used in floatation. In our study two methods of environmental toxicological tests were compared and applied to sediments of the Portman Bay (SE, Spain): the standardized toxicological test based on inhibition of luminescence employing Microtox

Analysis of perfluorinated carboxylic acids in soils II: optimization of chromatography and extraction.

PubMed

Washington, John W; Henderson, W Matthew; Ellington, J Jackson; Jenkins, Thomas M; Evans, John J

2008-02-15

With the objective of detecting and quantitating low concentrations of perfluorinated carboxylic acids (PFCAs), including perfluorooctanoic acid (PFOA), in soils, we compared the analytical suitability of liquid chromatography columns containing three different stationary phases, two different liquid chromatography-tandem mass spectrometry (LC/MS/MS) systems, and eight combinations of sample-extract pretreatments, extractions and cleanups on three test soils. For the columns and systems we tested, we achieved the greatest analytical sensitivity for PFCAs using a column with a C(18) stationary phase in a Waters LC/MS/MS. In this system we achieved an instrument detection limit for PFOA of 270 ag/microL, equating to about 14 fg of PFOA on-column. While an elementary acetonitrile/water extraction of soils recovers PFCAs effectively, natural soil organic matter also dissolved in the extracts commonly imparts significant noise that appears as broad, multi-nodal, asymmetric peaks that coelute with several PFCAs. The intensity and elution profile of this noise is highly variable among soils and it challenges detection of low concentrations of PFCAs by decreasing the signal-to-noise contrast. In an effort to decrease this background noise, we investigated several methods of pretreatment, extraction and cleanup, in a variety of combinations, that used alkaline and unbuffered water, acetonitrile, tetrabutylammonium hydrogen sulfate, methyl-tert-butyl ether, dispersed activated carbon and solid-phase extraction. For the combined objectives of complete recovery and minimization of background noise, we have chosen: (1) alkaline pretreatment; (2) extraction with acetonitrile/water; (3) evaporation to dryness; (4) reconstitution with tetrabutylammonium-hydrogen-sulfate ion-pairing solution; (5) ion-pair extraction to methyl-tert-butyl ether; (6) evaporation to dryness; (7) reconstitution with 60/40 acetonitrile/water (v/v); and (8) analysis by LC/MS/MS. Using this method, we detected in all three of our test soils, endogenous concentrations of all of our PFCA analytes, C(6) through C(10)-the lowest concentrations being roughly 30 pg/g of dry soil for perfluorinated hexanoic and decanoic acids in an agricultural soil.

Fingerprinting selection for agroenvironmental catchment studies: EDXRF analysis for solving complex artificial mixtures

NASA Astrophysics Data System (ADS)

Torres Astorga, Romina; Velasco, Hugo; Dercon, Gerd; Mabit, Lionel

2017-04-01

Soil erosion and associated sediment transportation and deposition processes are key environmental problems in Central Argentinian watersheds. Several land use practices - such as intensive grazing and crop cultivation - are considered likely to increase significantly land degradation and soil/sediment erosion processes. Characterized by highly erodible soils, the sub catchment Estancia Grande (12.3 km2) located 23 km north east of San Luis has been investigated by using sediment source fingerprinting techniques to identify critical hot spots of land degradation. The authors created 4 artificial mixtures using known quantities of the most representative sediment sources of the studied catchment. The first mixture was made using four rotation crop soil sources. The second and the third mixture were created using different proportions of 4 different soil sources including soils from a feedlot, a rotation crop, a walnut forest and a grazing soil. The last tested mixture contained the same sources as the third mixture but with the addition of a fifth soil source (i.e. a native bank soil). The Energy Dispersive X Ray Fluorescence (EDXRF) analytical technique has been used to reconstruct the source sediment proportion of the original mixtures. Besides using a traditional method of fingerprint selection such as Kruskal-Wallis H-test and Discriminant Function Analysis (DFA), the authors used the actual source proportions in the mixtures and selected from the subset of tracers that passed the statistical tests specific elemental tracers that were in agreement with the expected mixture contents. The selection process ended with testing in a mixing model all possible combinations of the reduced number of tracers obtained. Alkaline earth metals especially Strontium (Sr) and Barium (Ba) were identified as the most effective fingerprints and provided a reduced Mean Absolute Error (MAE) of approximately 2% when reconstructing the 4 artificial mixtures. This study demonstrates that the EDXRF fingerprinting approach performed very well in reconstructing our original mixtures especially in identifying and quantifying the contribution of the 4 rotation crop soil sources in the first mixture.

A two-stage extraction procedure for insensitive munition (IM) explosive compounds in soils.

PubMed

Felt, Deborah; Gurtowski, Luke; Nestler, Catherine C; Johnson, Jared; Larson, Steven

2016-12-01

The Department of Defense (DoD) is developing a new category of insensitive munitions (IMs) that are more resistant to detonation or promulgation from external stimuli than traditional munition formulations. The new explosive constituent compounds are 2,4-dinitroanisole (DNAN), nitroguanidine (NQ), and nitrotriazolone (NTO). The production and use of IM formulations may result in interaction of IM component compounds with soil. The chemical properties of these IM compounds present unique challenges for extraction from environmental matrices such as soil. A two-stage extraction procedure was developed and tested using several soil types amended with known concentrations of IM compounds. This procedure incorporates both an acidified phase and an organic phase to account for the chemical properties of the IM compounds. The method detection limits (MDLs) for all IM compounds in all soil types were <5 mg/kg and met non-regulatory risk-based Regional Screening Level (RSL) criteria for soil proposed by the U.S. Army Public Health Center. At defined environmentally relevant concentrations, the average recovery of each IM compound in each soil type was consistent and greater than 85%. The two-stage extraction method decreased the influence of soil composition on IM compound recovery. UV analysis of NTO established an isosbestic point based on varied pH at a detection wavelength of 341 nm. The two-stage soil extraction method is equally effective for traditional munition compounds, a potentially important point when examining soils exposed to both traditional and insensitive munitions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Towards a model-based inventory of soil organic carbon in agricultural soils for the Swiss greenhouse gas reporting

NASA Astrophysics Data System (ADS)

Staudt, K.; Leifeld, J.; Bretscher, D.; Fuhrer, J.

2012-04-01

The Swiss inventory submission under the United Nations Framework Convention on Climate Change (UNFCCC) reports on changes in soil organic carbon stocks under different land-uses and land-use changes. The approach currently employed for cropland and grassland soils combines Tier 1 and Tier 2 methods and is considered overly simplistic. As the UNFCC encourages countries to develop Tier 3 methods for national greenhouse gas reporting, we aim to build up a model-based inventory of soil organic carbon in agricultural soils in Switzerland. We conducted a literature research on currently employed higher-tier methods using process-based models in four countries: Denmark, Sweden, Finland and the USA. The applied models stem from two major groups differing in complexity - those belonging to the group of general ecosystem models that include a plant-growth submodel, e.g. Century, and those that simulate soil organic matter turnover but not plant-growth, e.g. ICBM. For the latter group, carbon inputs to the soil from plant residues and roots have to be determined separately. We will present some aspects of the development of a model-based inventory of soil organic carbon in agricultural soils in Switzerland. Criteria for model evaluation are, among others, modeled land-use classes and land-use changes, spatial and temporal resolution, and coverage of relevant processes. For model parameterization and model evaluation at the field scale, data from several long-term agricultural experiments and monitoring sites in Switzerland is available. A subsequent regional application of a model requires the preparation of regional input data for the whole country - among others spatio-temporal meteorological data, agricultural and soil data. Following the evaluation of possible models and of available data, preference for application in the Swiss inventory will be given to simpler model structures, i.e. models without a plant-growth module. Thus, we compared different allometric relations for the estimation of plant carbon inputs to the soil from yield data that are usually provided with the models. Calculated above- and below-ground carbon inputs vary substantially between methods and exhibit different sensitivities to yield data. As a benchmark, inputs to the soil from above- and below-ground crop residues are calculated with the IPCC default method. Furthermore, the suitability of these estimation methods for Swiss conditions is tested.

Preliminary studies of the CHIM electrogeochemical method at the Kokomo Mine, Russell Gulch, Colorado

USGS Publications Warehouse

Smith, D.B.; Hoover, D.B.; Sanzolone, R.F.

1993-01-01

The CHIM electrogeochemical exploration technique was developed in the former Soviet Union about 20 years ago and is claimed to be effective in exploration for concealed mineral deposits that are not detectable by other geochemical or geophysical techniques. The method involves providing a high-voltage direct current to an anode and an array of special collector cathodes. Cations mobile in the electric field are collected at the cathodes and their concentrations determined. The U.S. Geological Survey started a study of the CHIM method by conducting tests over a precious- and base-metal-bearing quartz vein covered with 3 m of colluvial soil and weathered bedrock near the Kokomo Mine, Colorado. The tests show that the CHIM method gives better definition of the vein than conventional soil geochemistry based on a total-dissolution technique. The CHIM technique gives reproducible geochemical anomaly patterns, but the absolute concentrations depend on local site variability as well as temporal variations. Weak partial dissolutions of soils at the Kokomo Mine by an enzyme leach, a dilute acetic acid leach, and a dilute hydrochloric acid leach show results comparable to those from the CHIM method. This supports the idea that the CHIM technique is essentially a weak in-situ partial extraction involving only ions able to move in a weak electric field. ?? 1993.

Extraction of polycyclic aromatic hydrocarbons and organochlorine pesticides from soils: a comparison between Soxhlet extraction, microwave-assisted extraction and accelerated solvent extraction techniques.

PubMed

Wang, Wentao; Meng, Bingjun; Lu, Xiaoxia; Liu, Yu; Tao, Shu

2007-10-29

The methods of simultaneous extraction of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) from soils using Soxhlet extraction, microwave-assisted extraction (MAE) and accelerated solvent extraction (ASE) were established, and the extraction efficiencies using the three methods were systemically compared from procedural blank, limits of detection and quantification, method recovery and reproducibility, method chromatogram and other factors. In addition, soils with different total organic carbon contents were used to test the extraction efficiencies of the three methods. The results showed that the values obtained in this study were comparable with the values reported by other studies. In some respects such as method recovery and reproducibility, there were no significant differences among the three methods for the extraction of PAHs and OCPs. In some respects such as procedural blank and limits of detection and quantification, there were significant differences among the three methods. Overall, ASE had the best extraction efficiency compared to MAE and Soxhlet extraction, and the extraction efficiencies of MAE and Soxhlet extraction were comparable to each other depending on the property such as TOC content of the studied soil. Considering other factors such as solvent consumption and extraction time, ASE and MAE are preferable to Soxhlet extraction.

Nickel speciation in several serpentine (ultramafic) topsoils via bulk synchrotron-based techniques

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

Siebecker, Matthew G.; Chaney, Rufus L.; Sparks, Donald L.

2017-07-01

Serpentine soils have elevated concentrations of trace metals including nickel, cobalt, and chromium compared to non-serpentine soils. Identifying the nickel bearing minerals allows for prediction of potential mobility of nickel. Synchrotron-based techniques can identify the solid-phase chemical forms of nickel with minimal sample treatment. Element concentrations are known to vary among soil particle sizes in serpentine soils. Sonication is a useful method to physically disperse sand, silt and clay particles in soils. Synchrotron-based techniques and sonication were employed to identify nickel species in discrete particle size fractions in several serpentine (ultramafic) topsoils to better understand solid-phase nickel geochemistry. Nickel commonlymore » resided in primary serpentine parent material such as layered-phyllosilicate and chain-inosilicate minerals and was associated with iron oxides. In the clay fractions, nickel was associated with iron oxides and primary serpentine minerals, such as lizardite. Linear combination fitting (LCF) was used to characterize nickel species. Total metal concentration did not correlate with nickel speciation and is not an indicator of the major nickel species in the soil. Differences in soil texture were related to different nickel speciation for several particle size fractionated samples. A discussion on LCF illustrates the importance of choosing standards based not only on statistical methods such as Target Transformation but also on sample mineralogy and particle size. Results from the F-test (Hamilton test), which is an underutilized tool in the literature for LCF in soils, highlight its usefulness to determine the appropriate number of standards to for LCF. EXAFS shell fitting illustrates that destructive interference commonly found for light and heavy elements in layered double hydroxides and in phyllosilicates also can occur in inosilicate minerals, causing similar structural features and leading to false positive results in LCF.« less

Geotechnical characterization of mined clay from Appalachian Ohio: challenges and implications for the clay mining industry.

PubMed

Moran, Anthony R; Hettiarachchi, Hiroshan

2011-07-01

Clayey soil found in coal mines in Appalachian Ohio is often sold to landfills for constructing Recompacted Soil Liners (RSL) in landfills. Since clayey soils possess low hydraulic conductivity, the suitability of mined clay for RSL in Ohio is first assessed by determining its clay content. When soil samples are tested in a laboratory, the same engineering properties are typically expected for the soils originated from the same source, provided that the testing techniques applied are standard, but mined clay from Appalachian Ohio has shown drastic differences in particle size distribution depending on the sampling and/or laboratory processing methods. Sometimes more than a 10 percent decrease in the clay content is observed in the samples collected at the stockpiles, compared to those collected through reverse circulation drilling. This discrepancy poses a challenge to geotechnical engineers who work on the prequalification process of RSL material as it can result in misleading estimates of the hydraulic conductivity of the samples. This paper describes a laboratory investigation conducted on mined clay from Appalachian Ohio to determine how and why the standard sampling and/or processing methods can affect the grain-size distributions. The variation in the clay content was determined to be due to heavy concentrations of shale fragments in the clayey soils. It was also concluded that, in order to obtain reliable grain size distributions from the samples collected at a stockpile of mined clay, the material needs to be processed using a soil grinder. Otherwise, the samples should be collected through drilling.

Degradation and movement in soil of the herbicide isoproturon analyzed by a Photosystem II-based biosensor.

PubMed

Malý, J; Klem, K; Lukavská, A; Masojídek, J

2005-01-01

We have examined the persistence and movement of a urea-type herbicide, isoproturon [IPU; 3-(4-isopropylphenyl)-1,1'-dimethylurea], in soil using a novel herbicide-detection device, the prototype of a portable electrochemical biosensor based on Photosystem II particles immobilized on printed electrodes, and evaluated its results against two other methods: (i) chlorophyll-fluorescence bioassay based on polyphasic induction curves, and (ii) standard analysis represented by liquid chromatography. The data of the herbicide's content determined in soil extracts from field experiments correlated in all three methods. The biosensor assay was effective in determining the herbicide's concentration to as low as 10(-7) M. The results of our experiments also showed the kinetics of movement, degradation, and persistence of isoproturon in various depths of soil. After 6 to 9 wk, almost half of the isoproturon was still actively present in the upper soil layers (0-10 and 10-20 cm) and only 5 to 10% of biological activity was inhibited in the deeper soil layer tested (20-30 cm). Thus, inhibition within the limit of detection of both bioassays could be observed up to 9 wk after application in all profiles (0-30 cm), whereas inhibition persisted for up to 11 wk in the upper soil profile (0-10 cm). The use of the biosensor demonstrated its possibility for making rapid and cheap phytotoxicity tests. Our biosensor can give preliminary information about the biological activity of isoproturon in hours--much faster than growth biotests that may take several days or more.

Geotechnical Characterization of Mined Clay from Appalachian Ohio: Challenges and Implications for the Clay Mining Industry

PubMed Central

Moran, Anthony R.; Hettiarachchi, Hiroshan

2011-01-01

Clayey soil found in coal mines in Appalachian Ohio is often sold to landfills for constructing Recompacted Soil Liners (RSL) in landfills. Since clayey soils possess low hydraulic conductivity, the suitability of mined clay for RSL in Ohio is first assessed by determining its clay content. When soil samples are tested in a laboratory, the same engineering properties are typically expected for the soils originated from the same source, provided that the testing techniques applied are standard, but mined clay from Appalachian Ohio has shown drastic differences in particle size distribution depending on the sampling and/or laboratory processing methods. Sometimes more than a 10 percent decrease in the clay content is observed in the samples collected at the stockpiles, compared to those collected through reverse circulation drilling. This discrepancy poses a challenge to geotechnical engineers who work on the prequalification process of RSL material as it can result in misleading estimates of the hydraulic conductivity of the samples. This paper describes a laboratory investigation conducted on mined clay from Appalachian Ohio to determine how and why the standard sampling and/or processing methods can affect the grain-size distributions. The variation in the clay content was determined to be due to heavy concentrations of shale fragments in the clayey soils. It was also concluded that, in order to obtain reliable grain size distributions from the samples collected at a stockpile of mined clay, the material needs to be processed using a soil grinder. Otherwise, the samples should be collected through drilling. PMID:21845150

Earthworms (Eisenia fetida) demonstrate potential for use in soil bioremediation by increasing the degradation rates of heavy crude oil hydrocarbons.

PubMed

Martinkosky, Luke; Barkley, Jaimie; Sabadell, Gabriel; Gough, Heidi; Davidson, Seana

2017-02-15

Crude oil contamination widely impacts soil as a result of release during oil and gas exploration and production activities. The success of bioremediation methods to meet remediation goals often depends on the composition of the crude oil, the soil, and microbial community. Earthworms may enhance bioremediation by mixing and aerating the soil, and exposing soil microorganisms to conditions in the earthworm gut that lead to increased activity. In this study, the common composting earthworm Eisenia fetida was tested for utility to improve remediation of oil-impacted soil. E. fetida survival in soil contaminated with two distinct crude oils was tested in an artificial (lab-mixed) sandy loam soil, and survival compared to that in the clean soil. Crude oil with a high fraction of light-weight hydrocarbons was more toxic to earthworms than the crude oil with a high proportion of heavy polyaromatic and aliphatic hydrocarbons. The heavier crude oil was added to soil to create a 30,000mg/kg crude oil impacted soil, and degradation in the presence of added earthworms and feed, feed alone, or no additions was monitored over time and compared. Earthworm feed was spread on top to test effectiveness of no mixing. TPH degradation rate for the earthworm treatments was ~90mg/day slowing by 200days to ~20mg/day, producing two phases of degradation. With feed alone, the rate was ~40mg/day, with signs of slowing after 500days. Both treatments reached the same end point concentrations, and exhibited faster degradation of aliphatic hydrocarbons C21, decreased. During these experiments, soils were moderately toxic during the first three months, then earthworms survived well, were active and reproduced with petroleum hydrocarbons present. This study demonstrated that earthworms accelerate bioremediation of crude oil in soils, including the degradation of the heaviest polyaromatic fractions. Copyright © 2016 Elsevier B.V. All rights reserved.

Murine norovirus detection in the exhaust air of IVCs is more sensitive than serological analysis of soiled bedding sentinels.

PubMed

Zorn, Julia; Ritter, Bärbel; Miller, Manuel; Kraus, Monika; Northrup, Emily; Brielmeier, Markus

2017-06-01

One limitation to housing rodents in individually ventilated cages (IVCs) is the ineffectiveness of traditional health monitoring programs that test soiled bedding sentinels every quarter. Aerogen transmission does not occur with this method. Moreover, the transmission of numerous pathogens in bedding is uncertain, and sentinel susceptibility to various pathogens varies. A novel method using particle collection from samples of exhaust air was developed in this study which was also systematically compared with routine health monitoring using soiled bedding sentinels. We used our method to screen these samples for the presence of murine norovirus (MNV), a mouse pathogen highly prevalent in laboratory animal facilities. Exhaust air particles from prefilters of IVC racks with known MNV prevalence were tested by quantitative reverse transcription polymerase chain reaction (RT-qPCR). MNV was detected in exhaust air as early as one week with one MNV-positive cage per rack, while sentinels discharged MNV RNA without seroconverting. MNV was reliably and repeatedly detected in particles collected from samples of exhaust air in all seven of the three-month sampling rounds, with increasing MNV prevalence, while sentinels only seroconverted in one round. Under field conditions, routine soiled bedding sentinel health monitoring in our animal facility failed to identify 67% ( n = 85) of positive samples by RT-qPCR of exhaust air particles. Thus, this method proved to be highly sensitive and superior to soiled bedding sentinels in the reliable detection of MNV. These results represent a major breakthrough in hygiene monitoring of rodent IVC systems and contribute to the 3R principles by reducing the number of animals used and by improving experimental conditions.

Reducing Methyl Halide Emissions from Soils

NASA Astrophysics Data System (ADS)

Yates, S. R.; Xuan, R.; Ashworth, D.; Luo, L.

2011-12-01

Volatilization and soil transformation are major pathways by which pesticides dissipate from treated agricultural soil. Methyl bromide (MeBr) emissions from agricultural fumigation can lead to depletion of the stratospheric ozone layer. This has led to a gradual phase-out of MeBr and replacement by other halogenated chemicals. However, MeBr continues to be widely used under Critical Use Exemptions and development of emission-reduction strategies remains important. Several methods to reduce emissions of MeBr, and other halogenated soil fumigants, have been developed and are currently being tested under field conditions. In this paper, several approaches for reducing fumigant emissions to the atmosphere are described and include the use of virtually impermeable films, the creation of reactive soil barriers and a recently developed reactive film which was designed to limit loss of MeBr from soil without adding any material to the soil surface. Ammonium thiosulfate (ATS) was used to create a reactive layer. For a reactive soil layer, ATS was sprayed on the soil surface or incorporated to a depth of 1-2 cm. For the reactive film, ATS was placed between two layers of plastic film. The lower plastic layer was a high-density polyethylene film (HDPE), which is readily permeable to MeBr. The upper layer was a virtually impermeable film (VIF) and limits MeBr diffusion. MeBr diffusion and transformation through VIFs and reactive layers were tested in laboratory and field experiments. Although ineffective when dry, when sufficient water was present, reactive barriers substantially depleted halogenated fumigants, including MeBr. When ATS was activated in laboratory experiments, MeBr half-life was about 9.0 h (20C) in a reactive film barrier, and half life decreased with increasing temperature. When the soil was covered with VIF, less than 10% of the added MeBr diffused through the film and the remainder was transformed within the soil. This compares with 60 to 90% emission losses, respectively, for a soil covered with HDPE or for a bare soil surface. These findings demonstrate that several methods are available to reduce atmospheric emissions of MeBr and other halogenated fumigants.

Using synthetic polymers to reduce soil erosion after forest fires in Mediterranean soils

NASA Astrophysics Data System (ADS)

Lado, Marcos; Ben-Hur, Meni; Inbar, Assaf

2010-05-01

Forest fires are a major environmental problem in the Mediterranean region because they result in a loss of vegetation cover, changes in biodiversity, increases in greenhouse gasses emission and a potential increase of runoff and soil erosion. The large increases in runoff and sediment yields after high severity fires have been attributed to several factors, among them: increase in soil water repellency; soil sealing by detached particles and by ash particles, and the loss of a surface cover. The presence of a surface cover increases infiltration, and decreases runoff and erosion by several mechanisms which include: rainfall interception, plant evapotranspiration, preservation of soil structure by increasing soil organic matter, and increasing surface roughness. The loss of vegetation cover as a result of fire leaves the surface of the soil exposed to the direct impact of the raindrops, and therefore the sensitivity of the soil to runoff generation and soil loss increases. In this work, we propose a new method to protect soils against post-fire erosion based on the application of synthetic polymers to the soil. Laboratory rainfall simulations and field runoff plots were used to analyze the suitability of the application of synthetic polymers to reduce soil erosion and stabilize soil structure in Mediterranean soils. The combination of these two processes will potentially favor a faster recovery of the vegetation structure. This method has been successfully applied in arable land, however it has not been tested in burnt forests. The outcome of this study may provide important managerial tools for forest management following fires.

Temporal variability of soil water repellency in field conditions under humid Mediterranean climate (South of Spain)

NASA Astrophysics Data System (ADS)

Martinez-Murillo, Juan F.; Gabarron-Galeote, Miguel A.; Ruiz-Sinoga, Jose D.

2013-04-01

Soil water repellency (SWR) has become an important field of scientific study because of its effects on soil hydrological behavior, including reduced matrix infiltration, development of fingered flow in structural or textural preferential flow paths, irregular wetting fronts, and increased runoff generation and soil erosion. The aim of this study is to evaluate the temporal variability of SWR in Mediterranean rangeland under humid Mediterranean climatic conditions (Tª=14.5 °C; P=1,010 mm y-1) in South of Spain. Every month from September 2008 to May 2009 (rainy season), soil moisture and SWR was measured in field conditions by means of gravimetric method and Water Drop Penetration Test, respectively. The entire tests were performed in differente eco-geomorphological conditions in the experimental site: North and South aspect hillslopes and beneath shrub and bare soil in every of them. The results indicate that: i) climatic conditions seem to be more transcendent than the vegetal cover for explaining the temporal variability of SWR in field conditions; ii) thus, SWR appears to be controlled by the antecedent rainfall and soil moisture; iii) more severity SWR were observed in patches characterized by sandier soils and/or greater organic matter contents; and iv) the factor 'hillslope aspect' was not found very influential in the degree of SWR.

Toxic Elements in Soil and Groundwater: Short-Time Study on Electrokinetic Removal of Arsenic in the Presence of other Ions

PubMed Central

Leszczynska, Danuta; Ahmad, Hafiz

2006-01-01

The electrokinetic technique is an emerging technology presently tested in situ to remove dissolved heavy metals from contaminated groundwater. There is a growing interest for using this system to cleanse clayey soil contaminated by toxic metallic ions. Currently, there are very few available non-destructive treatment methods that could be successfully applied in situ on low permeable type of soil matrix. The main objective of presented study was to validate and possibly enhance the overall efficiency of decontamination by the electrokinetic technique of the low permeable soil polluted by the arsenic in combination with chromium and copper ions. The chosen mixture of ions was imitating leak of pesticide well known as chromate copper arsenate (CCA). The chosen technique is showing a big promise to be used in the future as a portable, easy to install and run on sites with spills or leaks hard to reach otherwise; such as in the dense populated and urbanized areas. Laboratory electrokinetic experiments were designed to understand and possibly manipulate main mechanisms involved during forced migration of ions. All tests were conducted on artificially contaminated kaolinite (low permeable clay soil). Electrokinetic migration was inducted by the low voltage dc current applied through soil column. Series of experiments were designed to assess the efficiency of arsenic-chromium-copper remediation by applying (1) only dc current; and (2) by altering the soil environment. Obtained results showed that arsenic could be successfully removed from the soil in one day (25 hours) span. It was significant time reduction, very important during emergency response. Mass recovered at the end of each test depended on initial condition of soil and type of flushing solution. The best results were obtained, when soil was flushed with either NaOH or NaOCl (total removal efficiency 74.4% and 78.1%, respectively). Direct analysis of remained arsenic in soil after these tests confirmed substantial drop of the initial mass of arsenic in soil profile from 51.54 mg to 10.62 mg (NaOH) and 5.68 mg (NaOCl) after 25 hours of treatment. PMID:16823093

In situ detection of tree root distribution and biomass by multi-electrode resistivity imaging.

PubMed

Amato, Mariana; Basso, Bruno; Celano, Giuseppe; Bitella, Giovanni; Morelli, Gianfranco; Rossi, Roberta

2008-10-01

Traditional methods for studying tree roots are destructive and labor intensive, but available nondestructive techniques are applicable only to small scale studies or are strongly limited by soil conditions and root size. Soil electrical resistivity measured by geoelectrical methods has the potential to detect belowground plant structures, but quantitative relationships of these measurements with root traits have not been assessed. We tested the ability of two-dimensional (2-D) DC resistivity tomography to detect the spatial variability of roots and to quantify their biomass in a tree stand. A high-resolution resistivity tomogram was generated along a 11.75 m transect under an Alnus glutinosa (L.) Gaertn. stand based on an alpha-Wenner configuration with 48 electrodes spaced 0.25 m apart. Data were processed by a 2-D finite-element inversion algorithm, and corrected for soil temperature. Data acquisition, inversion and imaging were completed in the field within 60 min. Root dry mass per unit soil volume (root mass density, RMD) was measured destructively on soil samples collected to a depth of 1.05 m. Soil sand, silt, clay and organic matter contents, electrical conductivity, water content and pH were measured on a subset of samples. The spatial pattern of soil resistivity closely matched the spatial distribution of RMD. Multiple linear regression showed that only RMD and soil water content were related to soil resistivity along the transect. Regression analysis of RMD against soil resistivity revealed a highly significant logistic relationship (n = 97), which was confirmed on a separate dataset (n = 67), showing that soil resistivity was quantitatively related to belowground tree root biomass. This relationship provides a basis for developing quick nondestructive methods for detecting root distribution and quantifying root biomass, as well as for optimizing sampling strategies for studying root-driven phenomena.

DNA analysis of soil extracts can be used to investigate fine root depth distribution of trees

PubMed Central

Bithell, Sean L.; Tran-Nguyen, Lucy T. T.; Hearnden, Mark N.; Hartley, Diana M.

2015-01-01

Understanding the root distribution of trees by soil coring is time-consuming as it requires the separation of roots from soil and classification of roots into particular size classes. This labour-intensive process can limit sample throughput and therefore sampling intensity. We investigated the use of quantitative polymerase chain reaction (qPCR) on soil DNA extractions to determine live fine root DNA density (RDD, mg DNA m−2) for mango (Mangifera indica) trees. The specificity of the qPCR was tested against DNA extracted from 10 mango cultivars and 14 weed species. All mango cultivars and no weeds were detected. Mango DNA was successfully quantified from control soil spiked with mango roots and weed species. The DNA yield of mango root sections stored in moist soil at 23–28 °C declined after 15 days to low concentrations as roots decayed, indicating that dead root materials in moist soil would not cause false-positive results. To separate large roots from samples, a root separation method for field samples was used to target the root fragments remaining in sieved (minimum 2 mm aperture) soil for RDD comparisons. Using this method we compared the seasonal RDD values of fine roots for five mango rootstock cultivars in a field trial. The mean cultivar DNA yields by depth from root fragments in the sieved soil samples had the strongest relationship (adjusted multiple R2 = 0.9307, P < 0.001) with the dry matter (g m−2) of fine (diameter <0.64 mm) roots removed from the soil by sieving. This method provides a species-specific and rapid means of comparing the distribution and concentration of live fine roots of trees in orchards using soil samples up to 500 g. PMID:25552675

Design and evaluation of a bioreactor with application to forensic burial environments.

PubMed

Dunphy, Melissa A; Weisensee, Katherine E; Mikhailova, Elena A; Harman, Melinda K

2015-12-01

Existing forensic taphonomic methods lack specificity in estimating the postmortem interval (PMI) in the period following active decomposition. New methods, such as the use of citrate concentration in bone, are currently being considered; however, determining the applicability of these methods in differing environmental contexts is challenging. This research aims to design a forensic bioreactor that can account for environmental factors known to impact decomposition, specifically temperature, moisture, physical damage from animals, burial depth, soil pH, and organic matter content. These forensically relevant environmental variables were characterized in a soil science context. The resulting metrics were soil temperature regime, soil moisture regime, slope, texture, soil horizon, cation exchange capacity, soil pH, and organic matter content. Bioreactor chambers were constructed using sterilized thin-walled polystyrene boxes housed in calibrated temperature units. Gravesoil was represented using mineral soil (Ultisols), and organic soil proxy for Histosols, horticulture mix. Gravesoil depth was determined using mineral soil horizons A and Bt2 to simulate surface scatter and shallow grave burial respectively. A total of fourteen different environmental conditions were created and controlled successfully over a 90-day experiment. These results demonstrate successful implementation and control of forensic bioreactor simulating precise environments in a single research location, rather than site-specific testing occurring in different geographic regions. Bone sections were grossly assessed for weathering characteristics, which revealed notable differences related to exposure to different temperature regimes and soil types. Over the short 90-day duration of this experiment, changes in weathering characteristics were more evident across the different temperature regimes rather than the soil types. Using this methodology, bioreactor systems can be created to replicate many different clandestine burial contexts, which will allow for the more rapid understanding of environmental effects on skeletal remains. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Distribution of volatile organic compounds in soil vapor in the vicinity of a defense fuel supply point, Hanahan, South Carolina

USGS Publications Warehouse

Robertson, J.F.; Aelion, C.M.; Vroblesky, D.A.

1993-01-01

Two passive soil-vapor sampling techniques were used in the vicinity of a defense fuel supply point in Hanahan, South Carolina, to identify areas of potential contamination of the shallow water table aquifer by volatile organic compounds (VOC's). Both techniques involved the burial of samplers in the vadose zone and the saturated bottom sediments of nearby streams. One method, the empty-tube technique, allowed vapors to pass through a permeable membrane and accumulate inside an inverted empty test tube. A sample was extracted and analyzed on site by using a portable gas chromatograph. As a comparison to this method, an activated-carbon technique, also was used in certain areas. This method uses a vapor collector consisting of a test tube containing activated carbon as a sorbent for VOC's.

Comparison of drop size and velocity measurements by a laser precipitation meter and low-speed photography for an agriculture sprinkler

USDA-ARS?s Scientific Manuscript database

Kinetic energy of water droplets has a substantial effect on development of a soil surface seal and infiltration rate of bare soil. Methods for measuring sprinkler droplet size and velocity needed to calculate droplet kinetic energy have been developed and tested over the past 50 years, each with ad...

The history and future of methyl bromide alternatives in the southern United States

Treesearch

Tom E. Starkey

2012-01-01

This article gives a brief history of the efforts of the Southern Forest Nursery Management Cooperative (SFNMC) in testing methyl bromide (MBr) alternatives for soil fumigation. In the southeastern United States, fumigation with MBr has been the most commonly used method for producing high quality, pest-free forest seedlings in an environment that is conducive for soil...

Characterization and forensic analysis of soil samples using laser-induced breakdown spectroscopy (LIBS).

PubMed

Jantzi, Sarah C; Almirall, José R

2011-07-01

A method for the quantitative elemental analysis of surface soil samples using laser-induced breakdown spectroscopy (LIBS) was developed and applied to the analysis of bulk soil samples for discrimination between specimens. The use of a 266 nm laser for LIBS analysis is reported for the first time in forensic soil analysis. Optimization of the LIBS method is discussed, and the results compared favorably to a laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) method previously developed. Precision for both methods was <10% for most elements. LIBS limits of detection were <33 ppm and bias <40% for most elements. In a proof of principle study, the LIBS method successfully discriminated samples from two different sites in Dade County, FL. Analysis of variance, Tukey's post hoc test and Student's t test resulted in 100% discrimination with no type I or type II errors. Principal components analysis (PCA) resulted in clear groupings of the two sites. A correct classification rate of 99.4% was obtained with linear discriminant analysis using leave-one-out validation. Similar results were obtained when the same samples were analyzed by LA-ICP-MS, showing that LIBS can provide similar information to LA-ICP-MS. In a forensic sampling/spatial heterogeneity study, the variation between sites, between sub-plots, between samples and within samples was examined on three similar Dade sites. The closer the sampling locations, the closer the grouping on a PCA plot and the higher the misclassification rate. These results underscore the importance of careful sampling for geographic site characterization.

Multi-scale sensitivity analysis of pile installation using DEM

NASA Astrophysics Data System (ADS)

Esposito, Ricardo Gurevitz; Velloso, Raquel Quadros; , Eurípedes do Amaral Vargas, Jr.; Danziger, Bernadete Ragoni

2017-12-01

The disturbances experienced by the soil due to the pile installation and dynamic soil-structure interaction still present major challenges to foundation engineers. These phenomena exhibit complex behaviors, difficult to measure in physical tests and to reproduce in numerical models. Due to the simplified approach used by the discrete element method (DEM) to simulate large deformations and nonlinear stress-dilatancy behavior of granular soils, the DEM consists of an excellent tool to investigate these processes. This study presents a sensitivity analysis of the effects of introducing a single pile using the PFC2D software developed by Itasca Co. The different scales investigated in these simulations include point and shaft resistance, alterations in porosity and stress fields and particles displacement. Several simulations were conducted in order to investigate the effects of different numerical approaches showing indications that the method of installation and particle rotation could influence greatly in the conditions around the numerical pile. Minor effects were also noted due to change in penetration velocity and pile-soil friction. The difference in behavior of a moving and a stationary pile shows good qualitative agreement with previous experimental results indicating the necessity of realizing a force equilibrium process prior to any load-test to be simulated.

Multi-scale sensitivity analysis of pile installation using DEM

NASA Astrophysics Data System (ADS)

Esposito, Ricardo Gurevitz; Velloso, Raquel Quadros; , Eurípedes do Amaral Vargas, Jr.; Danziger, Bernadete Ragoni

2018-07-01

The disturbances experienced by the soil due to the pile installation and dynamic soil-structure interaction still present major challenges to foundation engineers. These phenomena exhibit complex behaviors, difficult to measure in physical tests and to reproduce in numerical models. Due to the simplified approach used by the discrete element method (DEM) to simulate large deformations and nonlinear stress-dilatancy behavior of granular soils, the DEM consists of an excellent tool to investigate these processes. This study presents a sensitivity analysis of the effects of introducing a single pile using the PFC2D software developed by Itasca Co. The different scales investigated in these simulations include point and shaft resistance, alterations in porosity and stress fields and particles displacement. Several simulations were conducted in order to investigate the effects of different numerical approaches showing indications that the method of installation and particle rotation could influence greatly in the conditions around the numerical pile. Minor effects were also noted due to change in penetration velocity and pile-soil friction. The difference in behavior of a moving and a stationary pile shows good qualitative agreement with previous experimental results indicating the necessity of realizing a force equilibrium process prior to any load-test to be simulated.

Degradation and adsorption of selected pharmaceuticals and personal care products (PPCPs) in agricultural soils.

PubMed

Xu, Jian; Wu, Laosheng; Chang, Andrew C

2009-11-01

Pharmaceuticals and personal care products (PPCPs) are emerging contaminants in the environment, which have drawn popular concerns recently. Most studies on the environmental fate of PPCPs have focused on their behaviors during wastewater treatment processes, in aquatic environments, and in the sludge, however, little is known about their behavior in agricultural soils. In this study, adsorption and degradation of six selected PPCPs, including clofibric acid, ibuprofen, naproxen, triclosan, diclofenac and bisphenol A have been investigated in the laboratory using four US agricultural soils associated with reclaimed wastewater reuse. Adsorption test using a batch equilibrium method demonstrated that adsorption of all tested chemicals in soils could be well described with Freundlich equation, and their adsorption affinity on soil followed the order of triclosan>bisphenol A>clofibric acid>naproxen>diclofenac>ibuprofen. Retardation factor (R(F)) suggested that ibuprofen had potential to move downward with percolating water, while triclosan and bisphenol A were readily retarded in soils. Degradation of selected PPCPs in soils generally followed first-order exponential decay kinetics, with half-lives ranging from 0.81 to 20.44 d. Degradation of PPCPs in soils appeared to be influenced by the soil organic matter and clay contents. Sterilization generally decreased the degradation rates, indicating microbial activity played a significant role in the degradation in soils. The degradation rate constant decreased with increasing initial chemical concentrations in soil, implying that the microbial activity was inhibited with high chemical loading levels.

Soil variability in engineering applications

NASA Astrophysics Data System (ADS)

Vessia, Giovanna

2014-05-01

Natural geomaterials, as soils and rocks, show spatial variability and heterogeneity of physical and mechanical properties. They can be measured by in field and laboratory testing. The heterogeneity concerns different values of litho-technical parameters pertaining similar lithological units placed close to each other. On the contrary, the variability is inherent to the formation and evolution processes experienced by each geological units (homogeneous geomaterials on average) and captured as a spatial structure of fluctuation of physical property values about their mean trend, e.g. the unit weight, the hydraulic permeability, the friction angle, the cohesion, among others. The preceding spatial variations shall be managed by engineering models to accomplish reliable designing of structures and infrastructures. Materon (1962) introduced the Geostatistics as the most comprehensive tool to manage spatial correlation of parameter measures used in a wide range of earth science applications. In the field of the engineering geology, Vanmarcke (1977) developed the first pioneering attempts to describe and manage the inherent variability in geomaterials although Terzaghi (1943) already highlighted that spatial fluctuations of physical and mechanical parameters used in geotechnical designing cannot be neglected. A few years later, Mandelbrot (1983) and Turcotte (1986) interpreted the internal arrangement of geomaterial according to Fractal Theory. In the same years, Vanmarcke (1983) proposed the Random Field Theory providing mathematical tools to deal with inherent variability of each geological units or stratigraphic succession that can be resembled as one material. In this approach, measurement fluctuations of physical parameters are interpreted through the spatial variability structure consisting in the correlation function and the scale of fluctuation. Fenton and Griffiths (1992) combined random field simulation with the finite element method to produce the Random Finite Element Method (RFEM). This method has been used to investigate the random behavior of soils in the context of a variety of classical geotechnical problems. Afterward, some following studies collected the worldwide variability values of many technical parameters of soils (Phoon and Kulhawy 1999a) and their spatial correlation functions (Phoon and Kulhawy 1999b). In Italy, Cherubini et al. (2007) calculated the spatial variability structure of sandy and clayey soils from the standard cone penetration test readings. The large extent of the worldwide measured spatial variability of soils and rocks heavily affects the reliability of geotechnical designing as well as other uncertainties introduced by testing devices and engineering models. So far, several methods have been provided to deal with the preceding sources of uncertainties in engineering designing models (e.g. First Order Reliability Method, Second Order Reliability Method, Response Surface Method, High Dimensional Model Representation, etc.). Nowadays, the efforts in this field have been focusing on (1) measuring spatial variability of different rocks and soils and (2) developing numerical models that take into account the spatial variability as additional physical variable. References Cherubini C., Vessia G. and Pula W. 2007. Statistical soil characterization of Italian sites for reliability analyses. Proc. 2nd Int. Workshop. on Characterization and Engineering Properties of Natural Soils, 3-4: 2681-2706. Griffiths D.V. and Fenton G.A. 1993. Seepage beneath water retaining structures founded on spatially random soil, Géotechnique, 43(6): 577-587. Mandelbrot B.B. 1983. The Fractal Geometry of Nature. San Francisco: W H Freeman. Matheron G. 1962. Traité de Géostatistique appliquée. Tome 1, Editions Technip, Paris, 334 p. Phoon K.K. and Kulhawy F.H. 1999a. Characterization of geotechnical variability. Can Geotech J, 36(4): 612-624. Phoon K.K. and Kulhawy F.H. 1999b. Evaluation of geotechnical property variability. Can Geotech J, 36(4): 625-639. Terzaghi K. 1943. Theoretical Soil Mechanics. New York: John Wiley and Sons. Turcotte D.L. 1986. Fractals and fragmentation. J Geophys Res, 91: 1921-1926. Vanmarcke E.H. 1977. Probabilistic modeling of soil profiles. J Geotech Eng Div, ASCE, 103: 1227-1246. Vanmarcke E.H. 1983. Random fields: analysis and synthesis. MIT Press, Cambridge.

Subsurface profiling using integrated geophysical methods for 2D site response analysis in Bangalore city, India: a new approach

NASA Astrophysics Data System (ADS)

Chandran, Deepu; Anbazhagan, P.

2017-10-01

Recently, site response analysis has become a mandatory step for the design of important structures. Subsurface investigation is an essential step, from where the input parameters for the site response study like density, shear wave velocity (Vs), thickness and damping characteristics, etc, are obtained. Most site response studies at shallow bedrock sites are one-dimensional (1D) and are usually carried out by using Vs from multi-channel analysis of surface waves (MASW) or a standard penetration test (SPT) for N values with assumptions that soil layers are horizontal, uniform and homogeneous. These assumptions are not completely true in shallow bedrock regions as soil deposits are heterogeneous. The objective of this study is to generate the actual subsurface profiles in two-dimensions at shallow bedrock regions using integrated subsurface investigation testing. The study area selected for this work is Bangalore, India. Three survey lines were selected in Bangalore at two different locations; one at the Indian Institute of Science (IISc) Campus and the other at Whitefield. Geophysical surveys like ground penetrating radar (GPR) and 2D MASW were carried out at these survey lines. Geophysical test results are compared and validated with a conventional geotechnical SPT. At the IISc site, the soil profile is obtained from a trench excavated for a proposed pipeline used to compare the geophysical test results. Test results show that GPR is very useful to delineate subsurface layers, especially for shallow depths at both sites (IISc Campus and Whitefield). MASW survey results show variation of Vs values and layer thickness comparatively at deeper depths for both sites. They also show higher density soil strata with high Vs value obtained at the IISc Campus site, whereas at the Whitefield site weaker soil with low shear velocity is observed. Combining these two geophysical methods helped to generate representative 2D subsurface profiles. These subsurface profiles can be further used to understand the difference between 1D and 2D site response.

Distribution and characteristics of gravelly soil liquefaction in the Wenchuan M s 8.0 earthquake

NASA Astrophysics Data System (ADS)

Cao, Zhenzhong; Hou, Longqing; Xu, Hongmei; Yuan, Xiaoming

2010-06-01

In this paper, a distribution map of gravelly soil liquefaction that was caused by the Wenchuan M s 8.0 earthquake in China is proposed based on a detailed field investigation and an analysis of geological soil profiles. The geological background of the earthquake disaster region is summarized by compiling geological cross sections and borehole logs. Meanwhile, four typical liquefied sites were selected to conduct sample drillings, dynamic penetration tests (DPT), and shear wave velocity tests, to understand the features of liquefied gravelly soil. One hundred and eighteen (118) liquefied sites were investigated shortly after the earthquake. The field investigation showed: (1) sandboils and waterspouts occurred extensively, involving thousands of miles of farmland, 120 villages, eight schools and five factories, which caused damage to some rural houses, schools, manufacturing facilities and wells, etc.; (2) the Chengdu plain is covered by a gravelly soil layer with a thickness of 0 m to 541 m according to the geological cross sections; (3) there were 80 gravelly soil liquefied sites in the Chengdu plain, shaped as five belt areas that varied from 20 km to 40 km in length, and about ten gravelly soil liquefied sites distributed within Mianyang area; and (4) the grain sizes of the sampled soil were relative larger than the ejected soil on the ground, thus the type of liquefied soil cannot be determined by the ejected soil. The gravelly soil liquefied sites are helpful in enriching the global database of gravelly soil liquefaction and developing a corresponding evaluation method in further research efforts.

Soil Health Assessment Approaches and the Cornell Framework

NASA Astrophysics Data System (ADS)

van Es, Harold

2016-04-01

Soil health constraints beyond nutrient limitations and excesses currently limit agroecosystem productivity and sustainability, resilience to drought and extreme rainfall, and progress in soil and water conservation. With mounting pressure to produce food, feed, fiber, and even fuel for an increasing population, the concept of soil health is gaining national and international attention. Multiple regional, national, and global efforts are now leveraging that work to reach new stakeholder audiences, so that soil health management is expanding into mainstream agriculture. Each grower is generally faced with a unique situation in the choice of management options to address soil health constraints and each system affords its own set of opportunities or limitations to soil management. A more comprehensive understanding of soil health status can better guide farmers' management decisions. Until recently, there has not been a formalized decision making process for implementing a soil health management system that alleviates field-specific constrains identified through standard measurements and then maintains improved soil health. This presentation will discuss current US-based efforts related to soil health assessment, including efforts to build national consensus on appropriate methods for simple (inexpensive) and comprehensive tests. This includes the Cornell Soil Health Management Planning and Implementation Framework. The most relevant components of the framework are 1) measurement of indicators that represent critical soil processes, 2) scoring of measured values that allows for interpretation, and 3) linkage of identified constraints with management practices. Land managers can monitor changes over time through further assessment, and adapt management practices to achieve chosen goals. We will discuss the full tests and approaches for simplification.

Soil structural quality assessment for soil protection regulation

NASA Astrophysics Data System (ADS)

Johannes, Alice; Boivin, Pascal

2017-04-01

Soil quality assessment is rapidly developing worldwide, though mostly focused on the monitoring of arable land and soil fertility. Soil protection regulations assess soil quality differently, focusing on priority pollutants and threshold values. The soil physical properties are weakly considered, due to lack of consensus and experimental difficulties faced with characterization. Non-disputable, easy to perform and inexpensive methods should be available for environmental regulation to be applied, which is unfortunately not the case. As a consequence, quantitative soil physical protection regulation is not applied, and inexpensive soil physical quality indicators for arable soil management are not available. Overcoming these limitations was the objective of a research project funded by the Swiss federal office for environment (FOEN). The main results and the perspectives of application are given in this presentation. A first step of the research was to characterize soils in a good structural state (reference soils) under different land use. The structural quality was assessed with field expertise and Visual Evaluation of the Soil Structure (VESS), and the physical properties were assessed with Shrinkage analysis. The relationships between the physical properties and the soil constituents were linear and highly determined. They represent the reference properties of the corresponding soils. In a second step, the properties of physically degraded soils were analysed and compared to the reference properties. This allowed defining the most discriminant parameters departing the different structure qualities and their threshold limits. Equivalent properties corresponding to these parameters but inexpensive and easy to determine were defined and tested. More than 90% of the samples were correctly classed with this method, which meets, therefore, the requirements for practical application in regulation. Moreover, result-oriented agri-environmental schemes for soil quality are now proposed to farmers based on these indicators.

Remediating pesticide contaminated soils using solvent extraction

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

Sahle-Demessie, E.; Meckes, M.C.; Richardson, T.L.

Bench-scale solvent extraction studies were performed on soil samples obtained from a Superfund site contaminated with high levels of p,p{prime}-DDT, p,p{prime}-DDE and toxaphene. The effectiveness of the solvent extraction process was assessed using methanol and 2-propanol as solvents over a wide range of operating conditions. It was demonstrated that a six-stage methanol extraction using a solvent-to-soil ratio of 1.6 can decrease pesticide levels in the soil by more than 99% and reduce the volume of material requiring further treatment by 25 times or more. The high solubility of the pesticides in methanol resulted in rapid extraction rates, with the systemmore » reaching quasi-equilibrium state in 30 minutes. The extraction efficiency was influenced by the number of extraction stages, the solvent-to-soil ratio, and the soil moisture content. Various methods were investigated to regenerate and recycle the solvent. Evaporation and solvent stripping are low cost and reliable methods for removing high pesticide concentrations from the solvent. For low concentrations, GAC adsorption may be used. Precipitating and filtering pesticides by adding water to the methanol/pesticide solution was not successful when tested with soil extracts. 26 refs., 10 figs., 6 tabs.« less

Failure behavior of concrete pile and super-structure dynamic response as a result of soil liquefaction during earthquake

NASA Astrophysics Data System (ADS)

Kaneda, Shogo; Hayashi, Kazuhiro; Hachimori, Wataru; Tamura, Shuji; Saito, Taiki

2017-10-01

In past earthquake disasters, numerous building structure piles were damaged by soil liquefaction occurring during the earthquake. Damage to these piles, because they are underground, is difficult to find. The authors aim to develop a monitoring method of pile damage based on superstructure dynamic response. This paper investigated the relationship between the damage of large cross section cementitious piles and the dynamic response of the super structure using a centrifuge test apparatus. A dynamic specimen used simple cross section pile models consisting of aluminum rod and mortar, a saturated soil (Toyoura sand) of a relative density of 40% and a super structure model of a natural period of 0.63sec. In the shaking table test under a 50G field (length scale of 1/50), excitation was a total of 3 motions scaled from the Rinkai wave at different amplitudes. The maximum acceleration of each of the excitations was 602gal, 336gal and 299gal. The centrifuge test demonstrated the liquefaction of saturated soil and the failure behavior of piles. In the test result, the damage of piles affected the predominant period of acceleration response spectrum on the footing of the superstructure.

Testing the application of Teflon/quartz soil solution samplers for DOM sampling in the Critical Zone: Field and laboratory approaches

NASA Astrophysics Data System (ADS)

Dolan, E. M.; Perdrial, J. N.; Vazquez, A.; Hernández, S.; Chorover, J.

2010-12-01

Elizabeth Dolan1,2, Julia Perdrial3, Angélica Vázquez-Ortega3, Selene Hernández-Ruiz3, Jon Chorover3 1Deptartment of Soil, Environmental, and Atmospheric Science, University of Missouri. 2Biosphere 2, University of Arizona. 3Deptartment of Soil, Water, and Environmental Science, University of Arizona. Abstract: The behavior of dissolved organic matter (DOM) in soil is important to many biogeochemical processes. Extraction methods to obtain DOM from the unsaturated zone remain a current focus of research as different methods can influence the type and concentration of DOM obtained. Thus, the present comparison study involves three methods for soil solution sampling to assess their impact on DOM quantity and quality: 1) aqueous soil extracts, 2) solution yielded from laboratory installed suction cup samplers and 3) solutions from field installed suction cup samplers. All samples were analyzed for dissolved organic carbon and total nitrogen concentrations. Moreover, DOM quality was analyzed using fluorescence, UV-Vis and FTIR spectroscopies. Results indicate higher DOC values for laboratory extracted DOM: 20 mg/L for aqueous soil extracts and 31 mg/L for lab installed samplers compared to 12 mg/L for field installed samplers. Large variations in C/N ratios were also observed ranging from 1.5 in laboratory extracted DOM to 11 in field samples. Fluorescence excitation-emission matrices of DOM solutions obtained for the laboratory extraction methods showed higher intensities in regions typical for fulvic and humic acid-like materials relative to those extracted in the field. Similarly, the molar absorptivity calculated from DOC concentration normalization of UV-Vis absorbance of the laboratory-derived solutions was significantly higher as well, indicating greater aromaticity. The observed differences can be attributed to soil disturbance associated with obtaining laboratory derived solution samples. Our results indicate that laboratory extraction methods are not comparable to in-situ field soil solution extraction in terms of DOM.

Pier and contraction scour prediction in cohesive soils at selected bridges in Illinois

USGS Publications Warehouse

Straub, Timothy D.; Over, Thomas M.

2010-01-01

This report presents the results of testing the Scour Rate In Cohesive Soils-Erosion Function Apparatus (SRICOS-EFA) method for estimating scour depth of cohesive soils at 15 bridges in Illinois. The SRICOS-EFA method for complex pier and contraction scour in cohesive soils has two primary components. The first component includes the calculation of the maximum contraction and pier scour (Zmax). The second component is an integrated approach that considers a time factor, soil properties, and continued interaction between the contraction and pier scour (SRICOS runs). The SRICOS-EFA results were compared to scour prediction results for non-cohesive soils based on Hydraulic Engineering Circular No. 18 (HEC-18). On average, the HEC-18 method predicted higher scour depths than the SRICOS-EFA method. A reduction factor was determined for each HEC-18 result to make it match the maximum of three types of SRICOS run results. The unconfined compressive strength (Qu) for the soil was then matched with the reduction factor and the results were ranked in order of increasing Qu. Reduction factors were then grouped by Qu and applied to each bridge site and soil. These results, and comparison with the SRICOS Zmax calculation, show that less than half of the reduction-factor method values were the lowest estimate of scour; whereas, the Zmax method values were the lowest estimate for over half. A tiered approach to predicting pier and contraction scour was developed. There are four levels to this approach numbered in order of complexity, with the fourth level being a full SRICOS-EFA analysis. Levels 1 and 2 involve the reduction factors and Zmax calculation, and can be completed without EFA data. Level 3 requires some surrogate EFA data. Levels 3 and 4 require streamflow for input into SRICOS. Estimation techniques for both EFA surrogate data and streamflow data were developed.

Improvements to measuring water flux in the vadose zone.

PubMed

Masarik, Kevin C; Norman, John M; Brye, Kristofor R; Baker, John M

2004-01-01

Evaluating the impact of land use practices on ground water quality has been difficult because few techniques are capable of monitoring the quality and quantity of soil water flow below the root zone without disturbing the soil profile and affecting natural flow processes. A recently introduced method, known as equilibrium tension lysimetry, was a major improvement but it was not a true equilibrium since it still required manual intervention to maintain proper lysimeter suction. We addressed this issue by developing an automated equilibrium tension lysimeter (AETL) system that continuously matches lysimeter tension to soil-water matric potential of the surrounding soil. The soil-water matric potential of the bulk soil is measured with a heat-dissipation sensor, and a small DC pump is used to apply suction to a lysimeter. The improved automated approach reported here was tested in the field for a 12-mo period. Powered by a small 12-V rechargeable battery, the AETLs were able to continuously match lysimeter suction to soil-water matric potential for 2-wk periods with minimal human attention, along with the added benefit of collecting continuous soil-water matric potential data. We also demonstrated, in the laboratory, methods for continuous measurement of water depth in the AETL, a capability that quantifies drainage on a 10-min interval, making it a true water-flux meter. Equilibrium tension lysimeters have already been demonstrated to be a reliable method of measuring drainage flux, and the further improvements have created a more effective device for studying water drainage and chemical leaching through the soil matrix.

Pathogen Decontamination of Food Crop Soil: A Review.

PubMed

Gurtler, Joshua B

2017-09-01

The purpose of this review is to delineate means of decontaminating soil. This information might be used to mitigate soil-associated risks of foodborne pathogens. The majority of the research in the published literature involves inactivation of plant pathogens in soil, i.e., those pathogens harmful to fruit and vegetable production and ornamental plants. Very little has been published regarding the inactivation of foodborne human pathogens in crop soil. Nevertheless, because decontamination techniques for plant pathogens might also be useful methods for eliminating foodborne pathogens, this review also includes inactivation of plant pathogens, with appropriate discussion and comparisons, in the hopes that these methods may one day be validated against foodborne pathogens. Some of the major soil decontamination methods that have been investigated and are covered include chemical decontamination (chemigation), solarization, steaming, biofumigation, bacterial competitive exclusion, torch flaming, microwave treatment, and amendment with biochar. Other innovative means of inactivating foodborne pathogens in soils may be discovered and explored in the future, provided that these techniques are economically feasible in terms of chemicals, equipment, and labor. Food microbiology and food safety researchers should reach out to soil scientists and plant pathologists to create links where they do not currently exist and strengthen relationships where they do exist to take advantage of multidisciplinary skills. In time, agricultural output and the demand for fresh produce will increase. With advances in the sensitivity of pathogen testing and epidemiological tracebacks, the need to mitigate preharvest bacterial contamination of fresh produce will become paramount. Hence, soil decontamination technologies may become more economically feasible and practical in light of increasing the microbial safety of fresh produce.

Measuring volatile organic compounds and stable isotopes emitted from trees and soils of the Biosphere 2 Rainforest

NASA Astrophysics Data System (ADS)

Meraz, J. C.; Meredith, L. K.; Van Haren, J. L. M.; Volkmann, T. H. M.

2017-12-01

Rainforest trees and soils play an important role in volatile organic compound (VOC) emissions. It is known that many rainforest tree species emit these organic compounds, such as terpenes, which can have an impact on the atmosphere and can be indicative of their metabolic functions. Some VOCs also absorb infrared radiation at wavelengths at which water isotopes are measured with laser spectrometers. Normal concentrations are not high enough for ambient sampling, but increased concentrations resulting from soil and plant samples extracted using equilibrium methods affect observed isotope ratios. There is thus a need to characterize volatile emissions from soil and plant samples, and to develop better methods to account for VOC interference during water isotope measurements. In this study, we collected soil and leaf samples from plants of the Biosphere 2 Rainforest Biome, a mesocosm system created to stimulate natural tropical rainforest habitats . Volatile concentrations were measured using a Gasmet DX4015 FTIR analyzer and a custom sampling system with sulfur hexafluoride (SF6) used as a tracer gas to test for leakage, and a commercial laser spectrometer was used for isotopic analysis. We determined that the different types of tree species emit different kinds of VOCs, such as isoprenes, alcohols, and aldehydes, that will potentially have to be accounted for. This study will help build the understanding of which organic compounds are emitted and develop new methods to test for water isotopes and gas fluxes in clear and precise measures. Such measures can help characterize the functioning of environmental systems such as the Biosphere 2 Rainforest Biome.

Evaluation of Propiconazole Application Methods for Control of Oak Wilt in Texas Live Oaks

Treesearch

A. Dan Wilson; D.G. Lester

1996-01-01

Four fungicide application methods using the microencapsulated (blue) 14.3% EC formulation of propiconazole (Alamo), including a low-concentration high volume method, two high-concentration low volume microinjection methods, and a low-concentration intermediate volume soil drench method, were tested for effectiveness in controlling oak wilt in a mature natural stand of...

Implementation of intelligent compaction technologies for road constructions in Wyoming.

DOT National Transportation Integrated Search

2015-03-01

Conventional test methods for roadway compaction cover less than 1% of roadway; whereas, intelligent : compaction (IC) offers a method to measure 100% of a roadway. IC offers the ability to increase : compaction uniformity of soils and asphalt paveme...

A design guide for subdivision pavements in Virginia.

DOT National Transportation Integrated Search

1973-01-01

The design method for secondary roads and that for subdivision roads are based on AASHO Road Test Results and Virginia's design experience. For flexible pavements, the methods are divided into two parts: (1) the evaluation of the soil support value o...

Handling the unknown soil hydraulic parameters in data assimilation for unsaturated flow problems

NASA Astrophysics Data System (ADS)

Lange, Natascha; Erdal, Daniel; Neuweiler, Insa

2017-04-01

Model predictions of flow in the unsaturated zone require the soil hydraulic parameters. However, these parameters cannot be determined easily in applications, in particular if observations are indirect and cover only a small range of possible states. Correlation of parameters or their correlation in the range of states that are observed is a problem, as different parameter combinations may reproduce approximately the same measured water content. In field campaigns this problem can be helped by adding more measurement devices. Often, observation networks are designed to feed models for long term prediction purposes (i.e. for weather forecasting). A popular way of making predictions with such kind of observations are data assimilation methods, like the ensemble Kalman filter (Evensen, 1994). These methods can be used for parameter estimation if the unknown parameters are included in the state vector and updated along with the model states. Given the difficulties related to estimation of the soil hydraulic parameters in general, it is questionable, though, whether these methods can really be used for parameter estimation under natural conditions. Therefore, we investigate the ability of the ensemble Kalman filter to estimate the soil hydraulic parameters. We use synthetic identical twin-experiments to guarantee full knowledge of the model and the true parameters. We use the van Genuchten model to describe the soil water retention and relative permeability functions. This model is unfortunately prone to the above mentioned pseudo-correlations of parameters. Therefore, we also test the simpler Russo Gardner model, which is less affected by that problem, in our experiments. The total number of unknown parameters is varied by considering different layers of soil. Besides, we study the influence of the parameter updates on the water content predictions. We test different iterative filter approaches and compare different observation strategies for parameter identification. Considering heterogeneous soils, we discuss the representativeness of different observation types to be used for the assimilation. G. Evensen. Sequential data assimilation with a nonlinear quasi-geostrophic model using Monte Carlo methods to forecast error statistics. Journal of Geophysical Research: Oceans, 99(C5):10143-10162, 1994

Evaluation of bearing capacity of piles from cone penetration test data.

DOT National Transportation Integrated Search

1999-11-01

This study presents an evaluation of the performance of eight cone penetration test (CPT) methods in predicting the ultimate load carrying capacity of square precast prestressed concrete (PPC) piles driven into Louisiana soils. A search in the DOTD f...

Use of hydraulic binders for reducing sulphate leaching: application to gypsiferous soil sampled in Ile-de-France region (France).

PubMed

Trincal, Vincent; Thiéry, Vincent; Mamindy-Pajany, Yannick; Hillier, Stephen

2018-06-01

Polluted soils are a serious environmental risk worldwide and consist of millions of tons of mineral waste to be treated. In order to ensure their sustainable management, various remediation options must be considered. Hydraulic binder treatment is one option that may allow a stabilisation of pollution and thus offer a valorisation as secondary raw materials rather than considering them as waste. In this study, we focused on sulphate-polluted soil and tested the effectiveness of several experimental hydraulic binders. The aim was to transform gypsum into ettringite, a much less soluble sulphate, and therefore to restrict the potential for sulphate pollutant release. The environmental assessment of five formulations using hydraulic binders was compared to the gypsiferous soil before treatment (contaminated in sulphate). The approach was to combine leaching tests with mineralogical quantifications using among others thermogravimetric and XRD methods. In the original soil and in the five formulations, leaching tests indicate sulphate release above environmental standards. However, hydraulic binders promote ettringite formation, as well as a gypsum content reduction as observed by SEM. The stabilisation of sulphates is, however, insufficient, probably as a result of the very high content of gypsum in the unusual soil used. The mineralogical reactions highlighted during the hydration of hydraulic binders are promising; they could pave the way for the development of new industrial mixtures that would have a positive environmental impact by allowing reuse of soils that would otherwise be classified as waste.

Closing the loop of the soil water retention curve

USGS Publications Warehouse

Lu, Ning; Alsherif, N; Wayllace, Alexandra; Godt, Jonathan W.

2015-01-01

The authors, to their knowledge for the first time, produced two complete principal soil water retention curves (SWRCs) under both positive and negative matric suction regimes. An innovative testing technique combining the transient water release and imbibition method (TRIM) and constant flow method (CFM) was used to identify the principal paths of SWRC in the positive pore-water pressure regime under unsaturated conditions. A negative matric suction of 9.8 kPa is needed to reach full saturation or close the loop of the SWRC for a silty soil. This work pushes the understanding of the interaction of soil and water into new territory by quantifying the boundaries of the SWRC over the entire suction domain, including both wetting and drying conditions that are relevant to field conditions such as slope wetting under heavy rainfall or rapid groundwater table rise in earthen dams or levees.

Dairy heifer manure management, dietary phosphorus, and soil test P effects on runoff phosphorus.

PubMed

Jokela, William E; Coblentz, Wayne K; Hoffman, Patrick C

2012-01-01

Manure application to cropland can contribute to runoff losses of P and eutrophication of surface waters. We conducted a series of three rainfall simulation experiments to assess the effects of dairy heifer dietary P, manure application method, application rate, and soil test P on runoff P losses from two successive simulated rainfall events. Bedded manure (18-21% solids) from dairy heifers fed diets with or without supplemental P was applied on a silt loam soil packed into 1- by 0.2-m sheet metal pans. Manure was either surface-applied or incorporated (Experiment 1) or surface-applied at two rates (Experiment 2) to supply 26 to 63 kg P ha. Experiment 3 evaluated runoff P from four similar nonmanured soils with average Bray P1-extractable P levels of 11, 29, 51, and 75 mg kg. We measured runoff quantity, total P (TP), dissolved reactive P (DRP), and total and volatile solids in runoff collected for 30 min after runoff initiation from two simulated rain events (70 mm h) 3 or 4 d apart. Manure incorporation reduced TP and DRP concentrations and load by 85 to 90% compared with surface application. Doubling the manure rate increased runoff DRP and TP concentrations an average of 36%. In the same experiment, P diet supplementation increased water-extractable P in manure by 100% and increased runoff DRP concentration threefold. Concentrations of solids, TP, and DRP in runoff from Rain 2 were 25 to 75% lower than from Rain 1 in Experiments 1 and 2. Runoff DRP from nonmanured soils increased quadratically with increasing soil test P. These results show that large reductions in P runoff losses can be achieved by incorporation of manure, avoiding unnecessary diet P supplementation, limiting manure application rate, and managing soils to prevent excessive soil test P levels. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Exploring the potential of the cosmic-ray neutron method to measure interception storage dynamics

NASA Astrophysics Data System (ADS)

Jakobi, Jannis; Bogena, Heye; Huisman, Johan Alexander; Diekkrüger, Bernd; Vereecken, Harry

2017-04-01

Cosmic-ray neutron soil moisture probes are an emerging technology that relies on the negative correlation between near-surface fast neutron counts and soil moisture content. Hydrogen atoms in the soil, which are mainly present as water, moderate the secondary neutrons on the way back to the surface. Any application of this method needs to consider the sensitivity of the neutron counts to additional sources of hydrogen (e.g. above- and below-ground biomass, humidity of the lower atmosphere, lattice water of the soil minerals, organic matter and water in the litter layer, intercepted water in the canopy, and soil organic matter). In this study, we analyzed the effects of canopy-intercepted water on the cosmic-ray neutron counts. For this, an arable field cropped with sugar beet was instrumented with several cosmic-ray neutron probes and a wireless sensor network with more than 140 in-situ soil moisture sensors. Additionally rainfall interception was estimated using a new approach coupling throughfall measurements and leaf wetness sensors. The derived interception storage was used to correct for interception effects on cosmic ray neutrons to enhance soil water content prediction. Furthermore, the potential for a simultaneous prediction of above- and below-ground biomass, soil moisture and interception was tested.

Characterization of Bacterial Community Dynamics during the Decomposition of Pig Carcasses in Simulated Soil Burial and Composting Systems.

PubMed

Ki, Bo-Min; Kim, Yu Mi; Jeon, Jun Min; Ryu, Hee Wook; Cho, Kyung-Suk

2017-12-28

Soil burial is the most widely used disposal method for infected pig carcasses, but composting has gained attention as an alternative disposal method because pig carcasses can be decomposed rapidly and safely by composting. To understand the pig carcass decomposition process in soil burial and by composting, pilot-scale test systems that simulated soil burial and composting were designed and constructed in the field. The envelope material samples were collected using special sampling devices without disturbance, and bacterial community dynamics were analyzed by high-throughput pyrosequencing for 340 days. Based on the odor gas intensity profiles, it was estimated that the active and advanced decay stages were reached earlier by composting than by soil burial. The dominant bacterial communities in the soil were aerobic and/or facultatively anaerobic gram-negative bacteria such as Pseudomonas, Gelidibacter, Mucilaginibacter , and Brevundimonas . However, the dominant bacteria in the composting system were anaerobic, thermophilic, endospore-forming, and/or halophilic gram-positive bacteria such as Pelotomaculum, Lentibacillus, Clostridium , and Caldicoprobacter . Different dominant bacteria played important roles in the decomposition of pig carcasses in the soil and compost. This study provides useful comparative date for the degradation of pig carcasses in the soil burial and composting systems.

Stability of Bradyrhizobium japonicum Inoculants after Introduction into Soil

PubMed Central

Brunel, Brigitte; Cleyet-Marel, Jean-Claude; Normand, Philippe; Bardin, Rene

1988-01-01

Bradyrhizobium japonicum USDA 125-Sp, USDA 138, and USDA 138-Sm had been used as inoculants for soybean (Glycine max (L.) Merr.) in soils previously free of B. japonicum. At 8 to 13 years after their release, these strains were reisolated from soil samples. A total of 115 isolates were obtained through nodules, and seven colonies were obtained directly by a serological method. The stability of the inoculants was confirmed by comparing the reisolated cultures with their respective parental strains which had been preserved by being lyophilized or stored on a yeast extract-mannitol agar slant at 4°C. Comparisons were made on morphological and serological characters, carbon compound utilization (8 tested), intrinsic antibiotic resistance (9 tested), and enzymatic activity (19 tested). Mucous and nonmucous isolates of serogroup 125 were analyzed for symbiotic effectiveness and restriction fragment hybridization with a DNA probe. Our data suggest that the B. japonicum inoculants have survived for up to 13 years in the soils without significant mutation except for two reisolates with a slightly increased kanamycin resistance level. Images PMID:16347768

Laboratory Performance of Five Selected Soil Moisture Sensors Applying Factory and Own Calibration Equations for Two Soil Media of Different Bulk Density and Salinity Levels.

PubMed

Matula, Svatopluk; Báťková, Kamila; Legese, Wossenu Lemma

2016-11-15

Non-destructive soil water content determination is a fundamental component for many agricultural and environmental applications. The accuracy and costs of the sensors define the measurement scheme and the ability to fit the natural heterogeneous conditions. The aim of this study was to evaluate five commercially available and relatively cheap sensors usually grouped with impedance and FDR sensors. ThetaProbe ML2x (impedance) and ECH₂O EC-10, ECH₂O EC-20, ECH₂O EC-5, and ECH₂O TE (all FDR) were tested on silica sand and loess of defined characteristics under controlled laboratory conditions. The calibrations were carried out in nine consecutive soil water contents from dry to saturated conditions (pure water and saline water). The gravimetric method was used as a reference method for the statistical evaluation (ANOVA with significance level 0.05). Generally, the results showed that our own calibrations led to more accurate soil moisture estimates. Variance component analysis arranged the factors contributing to the total variation as follows: calibration (contributed 42%), sensor type (contributed 29%), material (contributed 18%), and dry bulk density (contributed 11%). All the tested sensors performed very well within the whole range of water content, especially the sensors ECH₂O EC-5 and ECH₂O TE, which also performed surprisingly well in saline conditions.

Laboratory Performance of Five Selected Soil Moisture Sensors Applying Factory and Own Calibration Equations for Two Soil Media of Different Bulk Density and Salinity Levels

PubMed Central

Matula, Svatopluk; Báťková, Kamila; Legese, Wossenu Lemma

2016-01-01

Non-destructive soil water content determination is a fundamental component for many agricultural and environmental applications. The accuracy and costs of the sensors define the measurement scheme and the ability to fit the natural heterogeneous conditions. The aim of this study was to evaluate five commercially available and relatively cheap sensors usually grouped with impedance and FDR sensors. ThetaProbe ML2x (impedance) and ECH2O EC-10, ECH2O EC-20, ECH2O EC-5, and ECH2O TE (all FDR) were tested on silica sand and loess of defined characteristics under controlled laboratory conditions. The calibrations were carried out in nine consecutive soil water contents from dry to saturated conditions (pure water and saline water). The gravimetric method was used as a reference method for the statistical evaluation (ANOVA with significance level 0.05). Generally, the results showed that our own calibrations led to more accurate soil moisture estimates. Variance component analysis arranged the factors contributing to the total variation as follows: calibration (contributed 42%), sensor type (contributed 29%), material (contributed 18%), and dry bulk density (contributed 11%). All the tested sensors performed very well within the whole range of water content, especially the sensors ECH2O EC-5 and ECH2O TE, which also performed surprisingly well in saline conditions. PMID:27854263

Sprinkle Test by Phoenix's Robotic Arm (Movie)

NASA Technical Reports Server (NTRS)

2008-01-01

NASA's Phoenix Mars Lander used its Robotic Arm during the mission's 15th Martian day since landing (June 9, 2008) to test a 'sprinkle' method for delivering small samples of soil to instruments on the lander deck. This sequence of four images from the spacecraft's Surface Stereo Imager covers a period of 20 minutes from beginning to end of the activity.

In the single delivery of a soil sample to a Phoenix instrument prior to this test, the arm brought the scooped up soil over the instrument's opened door and turned over the scoop to release the soil. The sprinkle technique, by contrast, holds the scoop at a steady angle and vibrates the scoop by running the motorized rasp located beneath the scoop. This gently jostles some material out of the scoop to the target below.

For this test, the target was near the upper end the cover of the Microscopy, Electrochemistry and Conductivity Analyzer instrument suite, or MECA. The cover is 20 centimeters (7.9 inches) across. The scoop is about 8.5 centimeters (3.3 inches) across.

Based on the test's success in delivering a small quantity and fine-size particles, the Phoenix team plans to use the sprinkle method for delivering samples to MECA and to the Thermal and Evolved-Gas Analyzer, or TEGA. The next planned delivery is to MECA's Optical Microscope, via the port in the MECA cover visible at the bottom of these images.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Application of laboratory fungal resistance tests to solid wood and wood-plastic composite

Treesearch

Craig Merrill Clemons; Rebecca E. Ibach

2003-01-01

The fungal resistance of high density polyethylene filled with 50% wood flour was investigated using laboratory soil block tests. Modifications to standard test methods were made to increase initial moisture content, increase exposure surface area, and track moisture content, mechanical properties, and weight loss over the exposure period. Mechanical properties...

Energy dispersive X-ray fluorescence and scattering assessment of soil quality via partial least squares and artificial neural networks analytical modeling approaches.

PubMed

Kaniu, M I; Angeyo, K H; Mwala, A K; Mwangi, F K

2012-08-30

Soil quality assessment (SQA) calls for rapid, simple and affordable but accurate analysis of soil quality indicators (SQIs). Routine methods of soil analysis are tedious and expensive. Energy dispersive X-ray fluorescence and scattering (EDXRFS) spectrometry in conjunction with chemometrics is a potentially powerful method for rapid SQA. In this study, a 25 m Ci (109)Cd isotope source XRF spectrometer was used to realize EDXRFS spectrometry of soils. Glycerol (a simulate of "organic" soil solution) and kaolin (a model clay soil) doped with soil micro (Fe, Cu, Zn) and macro (NO(3)(-), SO(4)(2-), H(2)PO(4)(-)) nutrients were used to train multivariate chemometric calibration models for direct (non-invasive) analysis of SQIs based on partial least squares (PLS) and artificial neural networks (ANN). The techniques were compared for each SQI with respect to speed, robustness, correction ability for matrix effects, and resolution of spectral overlap. The method was then applied to perform direct rapid analysis of SQIs in field soils. A one-way ANOVA test showed no statistical difference at 95% confidence interval between PLS and ANN results compared to reference soil nutrients. PLS was more accurate analyzing C, N, Na, P and Zn (R(2)>0.9) and low SEP of (0.05%, 0.01%, 0.01%, and 1.98 μg g(-1)respectively), while ANN was better suited for analysis of Mg, Cu and Fe (R(2)>0.9 and SEP of 0.08%, 4.02 μg g(-1), and 0.88 μg g(-1) respectively). Copyright © 2012 Elsevier B.V. All rights reserved.

Revegetation of Acid Rock Drainage (ARD) Producing Slope Surface Using Phosphate Microencapsulation and Artificial Soil

NASA Astrophysics Data System (ADS)

Kim, Jae Gon

2017-04-01

Oxidation of sulfides produces acid rock drainage (ARD) upon their exposure to oxidation environment by construction and mining activities. The ARD causes the acidification and metal contamination of soil, surface water and groundwater, the damage of plant, the deterioration of landscape and the reduction of slope stability. The revegetation of slope surface is one of commonly adopted strategies to reduce erosion and to increase slope stability. However, the revegetation of the ARD producing slope surface is frequently failed due to its high acidity and toxic metal content. We developed a revegetation method consisting of microencapsualtion and artificial soil in the laboratory. The revegetation method was applied on the ARD producing slope on which the revegetation using soil coverage and seeding was failed and monitored the plant growth for one year. The phosphate solution was applied on sulfide containing rock to form stable Fe-phosphate mineral on the surface of sulfide, which worked as a physical barrier to prevent contacting oxidants such as oxygen and Fe3+ ion to the sulfide surface. After the microencapsulation, two artificial soil layers were constructed. The first layer containing organic matter, dolomite powder and soil was constructed at 2 cm thickness to neutralize the rising acidic capillary water from the subsurface and to remove the dissolved oxygen from the percolating rain water. Finally, the second layer containing seeds, organic matter, nutrients and soil was constructed at 3 cm thickness on the top. After application of the method, the pH of the soil below the artificial soil layer increased and the ARD production from the rock fragments reduced. The plant growth showed an ordinary state while the plant died two month after germination for the previous revegetation trial. No soil erosion occurred from the slope during the one year field test.

Isotopic Expression of Soil Denitrification across Gradients in Nitrogen and Carbon Availability

NASA Astrophysics Data System (ADS)

Walker, R.; Houlton, B. Z.; Perakis, S. S.

2016-12-01

Denitrification removes biologically available nitrogen (N) from ecosystems, making it an important control over the biosphere's N balance, with implications for air quality, human health and climate change. Despite its importance, estimates of the global soil denitrification flux remain highly uncertain. Major challenges lie in directly measuring the gaseous by-products of denitrification and scaling this complex microbial processes in both space and time. Process-based models constrained by empirical isotopic evidence have emerged as a method to help overcome these challenges. These models use the terrestrial 15N budget, along with soil moisture and N input data, to quantify denitrification fluxes and its gaseous forms, including NO, N2O and N2. However, the robustness of this method is limited by incomplete understanding of isotopic expression of denitrification and how it varies across known controls, such as carbon (C) and nitrate (NO3) availability. Here, we present a quantitative assessment of the isotope effect expression of in situ soil denitrification across gradients in N and C concentrations. This experiment tests the hypothesis that isotopic expression of soil denitrification (a kinetic process) increases with NO3 availability (reaction substrate) and decreases with increasing availability of organic C (electron donor). To test the impact of NO3 availability on the isotope effect of denitrification, field incubations experiments were conducted across a natural soil N gradient, ranging from 0.11 to 0.69% N. Similarly, the impact of electron donor availability was tested by conducting field incubations across a natural soil C gradient ranging from 1.94 to 11.60%. Data show that in lower N sites, the percent of NO3 consumed during the incubation was higher, while C availability neither affected the fraction of NO3 consumed nor the rate of consumption. These findings suggest that greater NO3 concentrations allow for greater isotope expression of denitrification in soil, supporting the working hypothesis. These results will be complemented by laboratory experiments in which NO3 concentration, C availability, and temperature are systematically varied. Future goals include the incorporation of these data into existing models to improve estimates of global N fluxes.

Mapping soil texture classes and optimization of the result by accuracy assessment

NASA Astrophysics Data System (ADS)

Laborczi, Annamária; Takács, Katalin; Bakacsi, Zsófia; Szabó, József; Pásztor, László

2014-05-01

There are increasing demands nowadays on spatial soil information in order to support environmental related and land use management decisions. The GlobalSoilMap.net (GSM) project aims to make a new digital soil map of the world using state-of-the-art and emerging technologies for soil mapping and predicting soil properties at fine resolution. Sand, silt and clay are among the mandatory GSM soil properties. Furthermore, soil texture class information is input data of significant agro-meteorological and hydrological models. Our present work aims to compare and evaluate different digital soil mapping methods and variables for producing the most accurate spatial prediction of texture classes in Hungary. In addition to the Hungarian Soil Information and Monitoring System as our basic data, digital elevation model and its derived components, geological database, and physical property maps of the Digital Kreybig Soil Information System have been applied as auxiliary elements. Two approaches have been applied for the mapping process. At first the sand, silt and clay rasters have been computed independently using regression kriging (RK). From these rasters, according to the USDA categories, we have compiled the texture class map. Different combinations of reference and training soil data and auxiliary covariables have resulted several different maps. However, these results consequentially include the uncertainty factor of the three kriged rasters. Therefore we have suited data mining methods as the other approach of digital soil mapping. By working out of classification trees and random forests we have got directly the texture class maps. In this way the various results can be compared to the RK maps. The performance of the different methods and data has been examined by testing the accuracy of the geostatistically computed and the directly classified results. We have used the GSM methodology to assess the most predictive and accurate way for getting the best among the several result maps. Acknowledgement: Our work was supported by the Hungarian National Scientific Research Foundation (OTKA, Grant No. K105167).

[Mixture Leaching Remediation Technology of Arsenic Contaminated Soil].

PubMed

Chen, Xun-feng; Li, Xiao-ming; Chen, Can; Yang, Qi; Deng, Lin-jing; Xie, Wei-qiang; Zhong, Yui; Huang, Bin; Yang, Wei-qiang; Zhang, Zhi-bei

2016-03-15

Soil contamination of arsenic pollution has become a severely environmental issue, while soil leaching is an efficient method for remediation of arsenic-contaminated soil. In this study, batch tests were primarily conducted to select optimal mixture leaching combination. Firstly, five conventional reagents were selected and combined with each other. Secondly, the fractions were analyzed before and after the tests. Finally, to explore the feasibility of mixed leaching, three soils with different arsenic pollution levels were used to compare the leaching effect. Comparing with one-step washing, the two-step sequential washing with different reagents increased the arsenic removal efficiency. These results showed that the mixture of 4 h 0.5 mol · L⁻¹ NaOH + 4 h 0.1 mol · L⁻¹ EDTA was found to be practicable, which could enhance the removal rate of arsenic from 66.67% to 91.83%, and the concentration of arsenic in soil was decreased from 186 mg · kg⁻¹ to 15.2 mg · kg⁻¹. Furthermore, the results indicated that the distribution of fractions of arsenic in soil changed apparently after mixture leaching. Leaching process could significantly reduce the available contents of arsenic in soil. Moreover, the mixture of 0.5 mol · L⁻¹ NaOH + 0.1 mol L⁻¹ EDTA could well decrease the arsenic concentration in aluminum-type soils, while the mixture of 0.5 mol · L⁻¹ OX + 0.5 mol · L⁻¹ NaOH could well decrease the arsenic concentration in iron-type soils.

Microbial soil community analyses for forensic science: Application to a blind test.

PubMed

Demanèche, Sandrine; Schauser, Leif; Dawson, Lorna; Franqueville, Laure; Simonet, Pascal

2017-01-01

Soil complexity, heterogeneity and transferability make it valuable in forensic investigations to help obtain clues as to the origin of an unknown sample, or to compare samples from a suspect or object with samples collected at a crime scene. In a few countries, soil analysis is used in matters from site verification to estimates of time after death. However, up to date the application or use of soil information in criminal investigations has been limited. In particular, comparing bacterial communities in soil samples could be a useful tool for forensic science. To evaluate the relevance of this approach, a blind test was performed to determine the origin of two questioned samples (one from the mock crime scene and the other from a 50:50 mixture of the crime scene and the alibi site) compared to three control samples (soil samples from the crime scene, from a context site 25m away from the crime scene and from the alibi site which was the suspect's home). Two biological methods were used, Ribosomal Intergenic Spacer Analysis (RISA), and 16S rRNA gene sequencing with Illumina Miseq, to evaluate the discriminating power of soil bacterial communities. Both techniques discriminated well between soils from a single source, but a combination of both techniques was necessary to show that the origin was a mixture of soils. This study illustrates the potential of applying microbial ecology methodologies in soil as an evaluative forensic tool. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Measuring soil organic matter turn over and carbon stabilisation in pasture soils using 13C enrichment methodology.

NASA Astrophysics Data System (ADS)

Robinson, J. M.; Barker, S.; Schipper, L. A.

2017-12-01

Carbon storage in soil is a balance between photosynthesis and respiration, however, not all C compounds decompose equally in soil. Soil C consists of several fractions of C ranging from, accessible C (rapidly cycling) to stored or protected C (slow cycling). The key to increasing C storage is through the transfer of soil C from this accessible fraction, where it can be easily lost through microbial degradation, into the more stable fraction. With the increasing use of isotope enrichment techniques, 13C may be used to trace the movement of newly incorporated carbon in soil and examine how land management practises affect carbon storage. A laboratory method was developed to rapidly analyse soil respired CO2 for δ13C to determine the temperature sensitivity of newly incorporated 13C enriched carbon. A Horotiu silt loam (2 mm sieved, 60% MWHC) was mixed with 13C enriched ryegrass/clover plant matter in Hungate tubes and incubated for 5 hours at 20 temperatures( 4 - 50 °C) using a temperature gradient method (Robinson J. M., et al, (2017) Biogeochemistry, 13, 101-112). The respired CO2 was analysed using a modified Los Gatos, Off-axis ICOS carbon dioxide analyser. This method was able to analyse the δ13C signature of respired CO2 as long as a minimum concentration of CO2 was produced per tube. Further analysis used a two-component mixing model to separate the CO2 into source components to determine the contribution of added C and soil to total respiration. Preliminary data showed the decomposition of the two sources of C were both temperature dependant. Overall this method is a relatively quick and easy way to analyse δ13C of respired soil CO2 samples, and will allow for the testing of the effects of multiple variables on the decomposition of carbon fractions in future use.

Selecting chemical and ecotoxicological test batteries for risk assessment of trace element-contaminated soils (phyto)managed by gentle remediation options (GRO).

PubMed

Kumpiene, Jurate; Bert, Valérie; Dimitriou, Ioannis; Eriksson, Jan; Friesl-Hanl, Wolfgang; Galazka, Rafal; Herzig, Rolf; Janssen, Jolien; Kidd, Petra; Mench, Michel; Müller, Ingo; Neu, Silke; Oustriere, Nadège; Puschenreiter, Markus; Renella, Giancarlo; Roumier, Pierre-Hervé; Siebielec, Grzegorz; Vangronsveld, Jaco; Manier, Nicolas

2014-10-15

During the past decades a number of field trials with gentle remediation options (GRO) have been established on trace element (TE) contaminated sites throughout Europe. Each research group selects different methods to assess the remediation success making it difficult to compare efficacy between various sites and treatments. This study aimed at selecting a minimum risk assessment battery combining chemical and ecotoxicological assays for assessing and comparing the effectiveness of GRO implemented in seven European case studies. Two test batteries were pre-selected; a chemical one for quantifying TE exposure in untreated soils and GRO-managed soils and a biological one for characterizing soil functionality and ecotoxicity. Soil samples from field studies representing one of the main GROs (phytoextraction in Belgium, Sweden, Germany and Switzerland, aided phytoextraction in France, and aided phytostabilization or in situ stabilization/phytoexclusion in Poland, France and Austria) were collected and assessed using the selected test batteries. The best correlations were obtained between NH4NO3-extractable, followed by NaNO3-extractable TE and the ecotoxicological responses. Biometrical parameters and biomarkers of dwarf beans were the most responsive indicators for the soil treatments and changes in soil TE exposures. Plant growth was inhibited at the higher extractable TE concentrations, while plant stress enzyme activities increased with the higher TE extractability. Based on these results, a minimum risk assessment battery to compare/biomonitor the sites phytomanaged by GROs might consist of the NH4NO3 extraction and the bean Plantox test including the stress enzyme activities. Copyright © 2014 Elsevier B.V. All rights reserved.

Direct rapid analysis of trace bioavailable soil macronutrients by chemometrics-assisted energy dispersive X-ray fluorescence and scattering spectrometry.

PubMed

Kaniu, M I; Angeyo, K H; Mwala, A K; Mangala, M J

2012-06-04

Precision agriculture depends on the knowledge and management of soil quality (SQ), which calls for affordable, simple and rapid but accurate analysis of bioavailable soil nutrients. Conventional SQ analysis methods are tedious and expensive. We demonstrate the utility of a new chemometrics-assisted energy dispersive X-ray fluorescence and scattering (EDXRFS) spectroscopy method we have developed for direct rapid analysis of trace 'bioavailable' macronutrients (i.e. C, N, Na, Mg, P) in soils. The method exploits, in addition to X-ray fluorescence, the scatter peaks detected from soil pellets to develop a model for SQ analysis. Spectra were acquired from soil samples held in a Teflon holder analyzed using (109)Cd isotope source EDXRF spectrometer for 200 s. Chemometric techniques namely principal component analysis (PCA), partial least squares (PLS) and artificial neural networks (ANNs) were utilized for pattern recognition based on fluorescence and Compton scatter peaks regions, and to develop multivariate quantitative calibration models based on Compton scatter peak respectively. SQ analyses were realized with high CMD (R(2)>0.9) and low SEP (0.01% for N and Na, 0.05% for C, 0.08% for Mg and 1.98 μg g(-1) for P). Comparison of predicted macronutrients with reference standards using a one-way ANOVA test showed no statistical difference at 95% confidence level. To the best of the authors' knowledge, this is the first time that an XRF method has demonstrated utility in trace analysis of macronutrients in soil or related matrices. Copyright © 2012 Elsevier B.V. All rights reserved.

Measurement of N2O and CH4 soil fluxes from garden, agricultural and natural soils using both closed and open chamber systems coupled with high-precision CRDS analyzer

NASA Astrophysics Data System (ADS)

He, Yonggang; Jacobson, Gloria; Alexander, Chris; Fleck, Derek; Hoffnagel, John; Del Campo, Bernardo; Rella, Chris

2013-04-01

Studying the emission and uptake of greenhouse gases from soil is essential for understanding, adapting to and ultimately mitigating the effects of climate change. To-date, majority of such studies have been focused on carbon dioxide (CO2 ) , however, in 2006 the EPA estimated that "Agricultural activities currently generate the largest share, 63 percent, of the world's anthropogenic non-carbon dioxide (non-CO2) emissions (84 percent of nitrous oxide [N2O] and 52 percent of methane[CH4]), and make up roughly 15 percent of all anthropogenic greenhouse gas emissions" (Prentice et al., 2001). Therefore, enabling accurate N2O and CH4 flux measurements in the field are clearly critical to our ability to better constrain carbon and nitrogen budgets, characterize soil sensitivities, agricultural practices, and microbial processes like denitrification and nitrification. To aide in these studies, Picarro has developed a new analyzer based on its proven, NIR technology platform, which is capable of measuring both N2O and CH4 down to ppb levels in a single, field-deployable analyzer. This analyzer measures N2O with a 1-sigma, precision of 3.5 ppb and CH4 with a 1-sigma precision of 3ppb on a 5 minute average. The instrument also has extremely low drift to enable accurate measurements with infrequent calibrations. The data rate of the analyzer is on the order of 5 seconds in order to capture fast, episodic emission events. One of the keys to making accurate CRDS measurements is to thoroughly characterize and correct for spectral interfering species. This is especially important for closed system soil chambers used on agricultural soils where a variety of soil amendments may be applied and gases not usually present in ambient air could concentrate to high levels. In this work, we present the results of analyzer interference testing and corrections completed for the interference of carbon dioxide, methane, ammonia, ethane, ethylene, acetylene, and water on N2O. In addition, we will present the results of testing done with the analyzer attached to both closed and open chamber systems to quantify fluxes of N2O and CH4 from active soil samples. The soil samples were collected by the University of Iowa from soil test sites used for studying the application of biochar as a soil amendment. Results will compare the two chamber methodologies and results from several soil sample types, garden, agricultural and natural. Preliminary results from laboratory measurements of soil core samples taken from a garden soil sample using the closed-system chamber method show N2O emission to be on the order of 5.67 x 10-2 μg/cm3*hr, which is in good agreement with the open-system chamber method tested on the same soil sample, which yielded fluxes of 6.01 x 10-2 μg/cm3*hr . Additional work presented will verify these initial results and will be compared to literature such as Hutchinsion and Livingston 1993 assessment of the bias of different chamber flux methodologies.

Effect of addition of GGBS and lime in soil stabilisation for stabilising local village roads in Thanjavur region

NASA Astrophysics Data System (ADS)

Saravanan, R.; Udhayakumar, T.; Dinesh, S.; Venkatasubramanian, C.; Muthu, D.

2017-07-01

Construction of pavements uses various filling materials and due to the cost factor, the local soil is used for pavement construction. The strength of the soil is improved by stabilisation. This stabilisation increases the load bearing capacities of soil for heavy wheeled vehicle traffic. GGBS, silica fume, rice husk are the basic waste materials used as a waste material, which improves the quality of soil and reduces the cost of pavements. In this study, a detailed investigation is made on the Ground Granulated Blast-furnace Slag (GGBS), activated by lime, in the stabilisation of low bearing capacity sand and clay soils collected from Thanjavur district (Budalur, Sengipatti, Vallam and Palliahgraharam villages). The tests are carried out as per Indian Standards. The test procedures separated into two phases, namely Stage-I and Stage-II. In Stage-I the soil tests include soil type, particle size distribution, soil index properties, standard proctor tests, shear tests and CBR test. In Stage-II the soil tests include shear tests and CBR test for the suitable required proportions of GGBS along with lime in the collected soil samples. The test results from stage-I and stage-II are compared and from the study, it is inferred that the application of GGBS is a useful material for soil stabilisation.

P losses in soil columns amended with compost and digestate from municipal solid wastes

NASA Astrophysics Data System (ADS)

García-Albacete, Marta; Cartagena, M. Carmen

2013-04-01

Sludge's, manures and compost applied to agricultural soils in high quantities and long-term application to increase crop productivity, result in accumulation of soil phosphorous (P). Soluble P is directly available to algae (Sonzogni et al., 1982) and thus particularly relevant to water quality degradation. Transport of P from agricultural soils to surface waters has been linked to eutrophication in fresh water and estuaries (Sharpley and Lemunyon, 1998). Almost 50% of stored water in Spain is degraded by eutrophication processes that cause the proliferation of algae and other organisms and a decrease in oxygen content (Environmental Profile of Spain 2005). Fertilizers and biodegradable wastes application rates in agriculture are based on nitrogen requirements. This results in a P supply that is in excess of crops needs since the ratio of P to N in waste use to be greater than required by plants (Smith, 1995). While surface runoff is an important pathway of phosphorus losses from agricultural lands, significant losses can also occur via leaching thought soils. Leaching tests are important for assessing the risk of release of potential pollutants from biodegradable wastes into groundwater or surface water. Percolation tests also get information about the interaction of organic waste with soils. The study was conducted according to the percolation leaching test CEN/TS 14405 "Characterization of waste-Leaching behavior test- Up-flow percolation test" with three different soils mixed with organic wastes from msw (compost and digestato) and an inorganic fertilizer (NaH2PO4). Each soil was amended with the P sources at rates of 100 kg P ha-1. Leachates were collected and analyzed for each column for dissolved reactive P by inductively coupled plasma atomic emission spectroscopy (ICP) following USEPA Method 3050A digestion (USEPA, 1995). The fact that P sorption capacity (Xmax, PSI) of the soils was determined using Langmuiŕs isotherms and the P forms from organic wastes were extensively characterized allows leaching data could be interpreted on the basis of P-sources chemical properties.

Evaluation of multi-walled carbon nanotubes as solid-phase extraction adsorbents of pesticides from agricultural, ornamental and forestal soils.

PubMed

Asensio-Ramos, M; Hernández-Borges, J; Borges-Miquel, T M; Rodríguez-Delgado, M A

2009-08-11

A new, simple and cost-effective method based on the use of multi-walled carbon nanotubes (MWCNTs) as solid-phase extraction stationary phases is proposed for the determination of a group of seven organophosphorus pesticides (i.e. ethoprophos, diazinon, chlorpyriphos-methyl, fenitrothion, malathion, chlorpyriphos and phosmet) and one thiadiazine (buprofezin) in different kinds of soil samples (forestal, ornamental and agricultural) using gas chromatography with nitrogen phosphorus detection. Soils were first ultrasound extracted with 10 mL 1:1 methanol/acetonitrile (v/v) and the evaporated extract redissolved in 20 mL water (pH 6.0) was passed through 100 mg of MWCNTs of 10-15 nm o.d., 2-6 nm i.d. and 0.1-10 microm length. Elution was carried out with 20 mL dichloromethane. The method was validated in terms of linearity, precision, recovery, accuracy and selectivity. Matrix-matched calibration was carried out for each type of soil since statistical differences between the calibration curves constructed in pure solvent and in the reconstituted soil extract were found for most of the pesticides under study. Recovery values of spiked samples ranged between 54 and 91% for the three types of soils (limits of detection (LODs) between 2.97 and 9.49 ngg(-1)), except for chlorpyrifos, chlorpyrifos-methyl and buprofezin which ranged between 12 and 54% (LODs between 3.14 and 72.4 ngg(-1)), which are the pesticides with the highest soil organic carbon sorption coefficient (K(OC)) values. Using a one-sample test (Student's t-test) with fortified samples at two concentration levels in each type of soil, no significant differences were observed between the real and the experimental values (accuracy percentages ranged between 87 and 117%). It is the first time that the adsorptive potential of MWCNTs for the extraction of organophosphorus pesticides from soils is investigated.

Ecotoxicological standard tests confirm beneficial effects of nitrate capture in organically coated grapewood biochar

NASA Astrophysics Data System (ADS)

Haller, Andreas; Kammann, Claudia; Löhnertz, Otmar

2017-04-01

Due to the rising use of mineral N fertilizers and legume use in agriculture, the input of reactive N into the global N cycle has dramatically increased. Therefore new agricultural techniques that increase N use efficiency and reduce the loss of soil mineral N to surface and ground waters are urgently required. Pyrogenic carbon (biochar) produced from biomass may be used as a beneficial soil amendment to sequester carbon (C) in soils, increase soil fertility in the long term, and reduce environmental pollution such as nitrate leaching or N2O emissions. However, reduced nitrate leaching is not a constant finding when using biochar as a soil amendment and the mechanisms are poorly understood. To investigate if biochar is able to reduce nitrate pollution and its subsequent effects on soil and aquatic fauna, we conducted a series of experiments using standard ecotoxicological test methods: (1) the collembolan reproduction test (ISO 11267 (1999)), (2) the earthworm reproduction test (ISO 11268-2 (1998)), (3) the aquatic Daphnia acute test (ISO 6341 (1996)) and (4) a seedling emergence and growth test (ISO 11269-2 (2006)) also involving leaching events. For the tests grapewood biochar produced with a Kon-Tiki kiln (600-700°C) was used which had previously demonstrated nitrate capture; terrestrial tests were carried out with loamy sand standard soil 2.2 (LUFA-Speyer, Germany). The tests included the factors: (A) nitrate addition (using critical values for the test organisms) or no nitrate addition, (B) control (no biochar), pure biochar and organically-coated biochar. In the aquatic test (3), a nitrate amount which caused 50% of the Daphnia-immobilizing toxic nitrate concentration in leachates was applied to the soil or soil-biochar mixtures. Subsequently, soils were incubated overnight and leached on the next day, producing (in the control) the calculated nitrate concentrations. Daphnids were incubated for 48 hours. Test results without nitrate confirmed that soil-biochar leachates did not impact Daphnia mobility. However, in the nitrate-amended control, Daphnia mobility was reduced by 52% as expected, while mobility was only reduced by 28% (pure BC) and by 16% (coated BC), respectively; this coincided with reduced nitrate concentrations in the leachates. In the presence of both biochars without high nitrate levels, adult earthworm biomass (2) was not different from that of the control, while the reproductive success (number of juvenile) increased by +46% with the coated biochar. With high nitrate concentrations, the reproductive success was strongly reduced by 96.7% (adult earthworm biomass remained constant). With the pure and coated biochars, the reproductive success increased by +171% and +678% compared to the (strongly reduced) soil-only control, respectively. The same response patterns were found in the collembolan test (1). In all cases biochar effects were correlated to nitrate capture in biochar particles which was more pronounced in the organically coated biochar. In conclusion post-treated biochars may be used as a tool for reducing nitrate pollution. However, more research is clearly needed. Acknowledgement: CK and AH gratefully acknowledge financial support of DFG grant KA3442/1-1 and the "OptiChar4EcoVin" project funded by the Hessian Ministry for Higher Education, Research and the Arts.

Active earth pressure model tests versus finite element analysis

NASA Astrophysics Data System (ADS)

Pietrzak, Magdalena

2017-06-01

The purpose of the paper is to compare failure mechanisms observed in small scale model tests on granular sample in active state, and simulated by finite element method (FEM) using Plaxis 2D software. Small scale model tests were performed on rectangular granular sample retained by a rigid wall. Deformation of the sample resulted from simple wall translation in the direction `from the soil" (active earth pressure state. Simple Coulomb-Mohr model for soil can be helpful in interpreting experimental findings in case of granular materials. It was found that the general alignment of strain localization pattern (failure mechanism) may belong to macro scale features and be dominated by a test boundary conditions rather than the nature of the granular sample.

Influence of environmental pollution with creosote oil or its vapors on biomass and selected physiological groups of microorganisms

NASA Astrophysics Data System (ADS)

Krzyśko-Łupicka, Teresa; Cybulska, Krystyna; Kołosowski, Paweł; Telesiński, Arkadiusz; Sudoł, Adam

2017-11-01

Survival of microorganisms in soils from treatment facility and landfill of wooden railway sleepers contaminated with creosote oil as well as in two types of soils with different content of organic carbon, treated with creosote oil vapors, was assessed. Microbiological assays including determination of: the biomass of living microorganisms method and the number of proteolytic, lipolytic and amylolytic microorganisms were carried out under laboratory conditions. Chromatography analysis of the soil extract from railway sleepers treatment facility was performed using GC/MS. The highest biomass and the number of tested microorganisms were determined in soils from wooden railway sleepers landfill, while the lowest in soil from the railway sleepers treatment facility. Vapors of creosote oil, regardless of the soil type, significantly increased only the number of lipolytic bacteria.

Are different soil metals near the homes of pregnant women associated with mild and severe intellectual disability in children?

PubMed Central

MCDERMOTT, SUZANNE; BAO, WEICHAO; TONG, XIN; CAI, BO; LAWSON, ANDREW; AELION, CMARJORIE

2014-01-01

AIM We explored the association of relatively low concentrations of metals in the soil proximal to maternal residence during pregnancy, with intellectual disability. We hypothesized different metals would be associated with mild versus severe intellectual disability. METHOD We used a mixed methods design, starting with a retrospective cohort from 1996–2002, of 10 051 pregnant mothers, soil sampling in the areas where these mothers resided during pregnancy, and follow-up of their children to determine if there was an intellectual disability outcome. We tested the soil and then predicted the soil concentration at the maternal homes, and modeled the association with the severity of the child’s intellectual disability. RESULTS We found a significant positive association between mild intellectual disability and soil mercury (p=0.007). For severe intellectual disability, there was a significant positive association with the soil arsenic and lead (p=0.025). INTERPRETATION This is the first report of the differential impact of metals in soil and severity of intellectual disability in children. Soil mercury concentration in the area the mother lived during pregnancy is associated with significantly increased odds of mild intellectual disability; a combination of arsenic and lead is associated with significantly increased odds of severe intellectual disability. These associations are present when controlling for maternal, child, and neighborhood characteristics. PMID:24750016

Thermal Conductivity Prediction of Soil in Complex Plant Soil System using Artificial Neural Networks

NASA Astrophysics Data System (ADS)

Wardani, A. K.; Purqon, A.

2016-08-01

Thermal conductivity is one of thermal properties of soil in seed germination and plants growth. Different soil types have different thermal conductivity. One of soft-computing promising method to predict thermal conductivity of soil types is Artificial Neural Network (ANN). In this study, we estimate the thermal conductivity of soil prediction in a soil-plant complex systems using ANN. With a feed-forward multilayer trained with back-propagation with 4, 10 and 1 on the input, hidden and output layers respectively. Our input are heating time, temperature and thermal resistance with thermal conductivity of soil as a target. ANN prediction demonstrates a good agreement with Mean Squared Error-testing (MSEte) of 9.56 x 10-7 for soils with green beans and those of bare soils is 7.00 × 10-7 respectively Green beans grow only on black-clay soil with a thermal conductivity of 0.7 W/m K with a sufficient water content. Our results demonstrate that temperature, moisture content, colour, texture and structure of soil are greatly affect to the thermal conductivity of soil in seed germination and plant growth. In future, it is potentially applied to estimate more complex compositions of plant-soil systems.

TESTING OF INDOOR RADON REDUCTION TECHNIQUES IN 19 MARYLAND HOUSES

EPA Science Inventory

The report gives results of testing of indoor radon reduction techniques in 19 existing houses in Maryland. The focus was on passive measures: various passive soil depressurization methods, where natural wind and temperature effects are utilized to develop suction in the system; ...

Field test of a new Australian method of rangeland monitoring

Treesearch

Suzanne Mayne; Neil West

2001-01-01

Managers need more efficient means of monitoring changes on the lands they manage. Accordingly, a new Australian approach was field tested and compared to the Daubenmire method of assessing plant cover, litter, and bare soil. The study area was a 2 mile wide by 30.15 mile long strip, mostly covered by salt desert shrub ecosystem types, centered along the SE boundary of...

Microwave brightness temperature and thermal inertia - towards synergistic method of high-resolution soil moisture retrieval

NASA Astrophysics Data System (ADS)

Lukowski, Mateusz; Usowicz, Boguslaw; Sagan, Joanna; Szlazak, Radoslaw; Gluba, Lukasz; Rojek, Edyta

2017-04-01

Soil moisture is an important parameter in many environmental studies, as it influences the exchange of water and energy at the interface between the land surface and the atmosphere. Accurate assessment of the soil moisture spatial and temporal variations is crucial for numerous studies; starting from a small scale of single field, then catchment, mesoscale basin, ocean conglomeration, finally ending at the global water cycle. Despite numerous advantages, such as fine accuracy (undisturbed by clouds or daytime conditions) and good temporal resolution, passive microwave remote sensing of soil moisture, e.g. SMOS and SMAP, are not applicable to a small scale - simply because of too coarse spatial resolution. On the contrary, thermal infrared-based methods of soil moisture retrieval have a good spatial resolution, but are often disturbed by clouds and vegetation interferences or night effects. The methods that base on point measurements, collected in situ by monitoring stations or during field campaigns, are sometimes called "ground truth" and may serve as a reference for remote sensing, of course after some up-scaling and approximation procedures that are, unfortunately, potential source of error. Presented research concern attempt to synergistic approach that join two remote sensing methods: passive microwave and thermal infrared, supported by in situ measurements. Microwave brightness temperature of soil was measured by ELBARA, the radiometer at 1.4 GHz frequency, installed at 6 meters high tower at Bubnow test site in Poland. Thermal inertia around the tower was modelled using the statistical-physical model whose inputs were: soil physical properties, its water content, albedo and surface temperatures measured by an infrared pyrometer, directed at the same footprint as ELBARA. The results coming from this method were compared to in situ data obtained during several field campaigns and by the stationary agrometeorological stations. The approach seems to be reasonable, as both variables, brightness temperature and thermal inertia, strongly depend on soil moisture. Despite the fact that the presented research focused on modelling in the small size, 4 ha test site, the method is promising for larger scales as well, due to similarities between ELBARA and SMOS and between pyrometer and satellite imaging spectrometers (Landsat, Sentinel etc.). The approach will merge advantages: high accuracy of passive microwave sensing with a good spatial resolution of thermal infrared methods. The work was partially funded under two ESA projects: 1) "ELBARA_PD (Penetration Depth)" No. 4000107897/13/NL/KML, funded by the Government of Poland through an ESA-PECS contract (Plan for European Cooperating States). 2) "Technical Support for the fabrication and deployment of the radiometer ELBARA-III in Bubnow, Poland" No. 4000113360/15/NL/FF/gp.

Development of a New Apparatus for Investigating Acoustic Effects on Hydraulic Properties of Low-Permeability Geo-Materials

NASA Astrophysics Data System (ADS)

Nakajima, H.; Sawada, A.; Sugita, H.; Takeda, M.; Komai, T.; Zhang, M.

2006-12-01

Remediation of polluted soils and groundwater contaminated by heavy metals and non-aqueous phase liquids has been one of the challenging issues in the field of geo-environments. In-situ removal of the contaminants from low permeable soils, such as clay strata, is particularly difficult because of the low mobility, strong adsorption, and/or other various interactions within soils. Thus current remediation techniques, such as pump- and-treat method and even eletrokinetic method, generally suffer from low recovery rates and/or economically unacceptable long remediation periods. A perspective improvement in remediation technology is to couple the electrokinetic method with an application of acoustic waves. This so-called Electro-Acoustic Soil Decontamination (EASD) method has been proposed by Battelle Columbus Labs.(Muralidhara et al. 1990). Simultaneous application of an electric field and an acoustic field may produce a synergistic effect and result in further enhancement of water transport by electro-osmosis in principle, but there is still no fundamental data for the design of EASD method in practical applications. A number of investigations have shown that an application of acoustic waves can increase hydraulic conductivity and mobility of non-aqueous phase liquids in porous media. Most of the prior and ongoing researches in this area have been focused on increasing production from declining oil and gas reservoirs. During several field tests by the oil and gas industries, increases in oil production rates by 20% or more have been reported. However, underlying physical mechanisms for acoustically enhanced fluid transport are not adequately understood. In addition, majority of the past investigations has dealt with applications of large amplitude of acoustic waves to relatively permeable soils or fractured rocks, and there is little information if acoustic wave effectively enhances flow and contaminant transport for less permeable clayey soils. To evaluate the feasibility of the EASD method and to obtain the fundamental but important knowledge for the design of this method, it is first necessary to understand the effects of acoustic wave application on pore water flow behavior. A new apparatus is developed to investigate the effects of acoustic wave on hydraulic properties of soil sample. This test apparatus enables to confine a cylindrical specimen under hydrostatic pressure conditions and to apply acoustic wave simultaneously. Preliminary results associated with the effects of acoustic wave frequency on changes of permeability of kaolin clay samples are illustrated in this report. A program investigating the effects of electricity and pore water chemistry on efficiency of decontamination using the same samples is also ongoing and briefly presented. The two strategies for enhancing the efficiency of remediation for low permeable soils will be combined in the near future

Shear-wave velocity-based probabilistic and deterministic assessment of seismic soil liquefaction potential

USGS Publications Warehouse

Kayen, R.; Moss, R.E.S.; Thompson, E.M.; Seed, R.B.; Cetin, K.O.; Der Kiureghian, A.; Tanaka, Y.; Tokimatsu, K.

2013-01-01

Shear-wave velocity (Vs) offers a means to determine the seismic resistance of soil to liquefaction by a fundamental soil property. This paper presents the results of an 11-year international project to gather new Vs site data and develop probabilistic correlations for seismic soil liquefaction occurrence. Toward that objective, shear-wave velocity test sites were identified, and measurements made for 301 new liquefaction field case histories in China, Japan, Taiwan, Greece, and the United States over a decade. The majority of these new case histories reoccupy those previously investigated by penetration testing. These new data are combined with previously published case histories to build a global catalog of 422 case histories of Vs liquefaction performance. Bayesian regression and structural reliability methods facilitate a probabilistic treatment of the Vs catalog for performance-based engineering applications. Where possible, uncertainties of the variables comprising both the seismic demand and the soil capacity were estimated and included in the analysis, resulting in greatly reduced overall model uncertainty relative to previous studies. The presented data set and probabilistic analysis also help resolve the ancillary issues of adjustment for soil fines content and magnitude scaling factors.

Testing of some assumptions about biodegradability in soil as measured by carbon dioxide evolution

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

El-Din Sharabi, N.; Bartha, R.

1993-04-01

The Toxic Substance Control Act calls for a premanufacturing review of novel chemical substances including their biodegradability. Carbon dioxide evolution, using non-labeled carbon or [sup 14]C, is a common method of testing. This study examines assumptions of carbon dioxide evolution testing. Test substances used included: glucose, adipic acid, benzoic acid, and n-hexadecane. Chemical composition other than carbon content appears to influence minimally the percentages conversion to CO[sub 2]. However, that although CO[sub 2] evolution seemed proportional to the carbon content and concentration of the test substance, at least one-half of the evolved net CO[sub 2] did not come directly frommore » the test substance. Conversion to CO[sub 2] in the soil appeared to depend on carbon content only. In experiments of 1 month or longer, the net CO[sub 2] evolution in response to substrate may be above 100% of the added substrate carbon. Whether this applies to all substrate additions remains to be studied. The authors conclude that net CO[sub 2] and [sup 14]CO[sub 2] evolution measurements are useful as a first-tier tests for assessing biodegradability in soil. 11 refs., 6 figs.« less

A fluidized bed desorption system for recycling mercury from contaminated soil

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

Harriss, C.; Baum, D.L. Jr.; Read, W.L.

1995-12-31

The land disposal restrictions effective for wastes containing mercury have created a need for technologies that can meet the best demonstrated available technologies (BDAT) treatment standards. In the past, technologies for mercury were in short supply. In addition to the already existing short supply, the natural gas industry has begun to remediate the numerous metering sites that have been contaminated with mercury from manometers installed along their pipelines. To meet the need for a mercury technology, Philip Environmental Services Corporation (Philip) evaluated and tested two different technologies capable of recovering mercury from contaminated soil. Philip initially performed some tests usingmore » gravitational methods followed by pilot-scale testing using a fluidized bed desorber. As a result of the testing, Philip constructed a full-scale fluidized bed system which can recover mercury from contaminated soil and debris. The name of Philip`s technology is the Solvating Vapor Pressure Process (SVPP). The main purpose of this paper is to discuss the results of the SVPP pilot testing and describe the process.« less

Performance of chromatographic systems to model soil-water sorption.

PubMed

Hidalgo-Rodríguez, Marta; Fuguet, Elisabet; Ràfols, Clara; Rosés, Martí

2012-08-24

A systematic approach for evaluating the goodness of chromatographic systems to model the sorption of neutral organic compounds by soil from water is presented in this work. It is based on the examination of the three sources of error that determine the overall variance obtained when soil-water partition coefficients are correlated against chromatographic retention factors: the variance of the soil-water sorption data, the variance of the chromatographic data, and the variance attributed to the dissimilarity between the two systems. These contributions of variance are easily predicted through the characterization of the systems by the solvation parameter model. According to this method, several chromatographic systems besides the reference octanol-water partition system have been selected to test their performance in the emulation of soil-water sorption. The results from the experimental correlations agree with the predicted variances. The high-performance liquid chromatography system based on an immobilized artificial membrane and the micellar electrokinetic chromatography systems of sodium dodecylsulfate and sodium taurocholate provide the most precise correlation models. They have shown to predict well soil-water sorption coefficients of several tested herbicides. Octanol-water partitions and high-performance liquid chromatography measurements using C18 columns are less suited for the estimation of soil-water partition coefficients. Copyright © 2012 Elsevier B.V. All rights reserved.

Integration of behavioral tests and biochemical biomarkers of terrestrial isopod Porcellio scaber (Isopoda, Crustacea) is a promising methodology for testing environmental safety of chars.

PubMed

Madžarić, Suzana; Kos, Monika; Drobne, Damjana; Hočevar, Matej; Jemec Kokalj, Anita

2018-03-01

We investigated how different carbonized materials, or chars (olive mill pomace biochar (BC) and urban greens pruning residues hydrochar (HC)) affect an important member of soil fauna, the terrestrial isopod Porcellio scaber. The selection behavior of isopods towards chars after a 48 h exposure was studied in (i) soil-char amended tests with single and multiple choices, and (ii) tests with chars offered as pure material. Finally, we exposed the isopods to char-amended soils for a period of 14 days to follow the effect on food consumption, body mass and activities of enzymes that are commonly altered upon stressor exposure (acetylcholinesterase, AChE, and glutathione S-transferase, GST). We showed that isopods are able to select between char amended and un-amended soil and different forms of char amendments: a clear preference for BC, and avoidance of HC were evidenced. The preferences remained the same when the chars were sterilized leading to the conclusion that initial microorganism composition was not the reason for selection, but selection was governed by other chars' physico-chemical properties. It remains to be elucidated which of these properties were the dominant reason for the selection. We also showed that isopods intentionally use BC as food at a similar rate to alder leaves. Medium-term exposure to HC resulted in adverse effects on isopods because it led to reduced feeding and growth, in addition to increasing GST activity, although no alterations in AChE activity were found. We suggest that behavioral tests with P. scaber could be used as a fast, reliable and economically feasible screening method for determining the safety of chars for the soil environment. Results represent significant contribution in the field of char toxicity testing, highlighting the importance of tests with isopods as important members of soil meso fauna, with the aim of influencing environmental policies and quality standards. Copyright © 2017 Elsevier Ltd. All rights reserved.

Handwashing and Ebola virus disease outbreaks: A randomized comparison of soap, hand sanitizer, and 0.05% chlorine solutions on the inactivation and removal of model organisms Phi6 and E. coli from hands and persistence in rinse water.

PubMed

Wolfe, Marlene K; Gallandat, Karin; Daniels, Kyle; Desmarais, Anne Marie; Scheinman, Pamela; Lantagne, Daniele

2017-01-01

To prevent Ebola transmission, frequent handwashing is recommended in Ebola Treatment Units and communities. However, little is known about which handwashing protocol is most efficacious. We evaluated six handwashing protocols (soap and water, alcohol-based hand sanitizer (ABHS), and 0.05% sodium dichloroisocyanurate, high-test hypochlorite, and stabilized and non-stabilized sodium hypochlorite solutions) for 1) efficacy of handwashing on the removal and inactivation of non-pathogenic model organisms and, 2) persistence of organisms in rinse water. Model organisms E. coli and bacteriophage Phi6 were used to evaluate handwashing with and without organic load added to simulate bodily fluids. Hands were inoculated with test organisms, washed, and rinsed using a glove juice method to retrieve remaining organisms. Impact was estimated by comparing the log reduction in organisms after handwashing to the log reduction without handwashing. Rinse water was collected to test for persistence of organisms. Handwashing resulted in a 1.94-3.01 log reduction in E. coli concentration without, and 2.18-3.34 with, soil load; and a 2.44-3.06 log reduction in Phi6 without, and 2.71-3.69 with, soil load. HTH performed most consistently well, with significantly greater log reductions than other handwashing protocols in three models. However, the magnitude of handwashing efficacy differences was small, suggesting protocols are similarly efficacious. Rinse water demonstrated a 0.28-4.77 log reduction in remaining E. coli without, and 0.21-4.49 with, soil load and a 1.26-2.02 log reduction in Phi6 without, and 1.30-2.20 with, soil load. Chlorine resulted in significantly less persistence of E. coli in both conditions and Phi6 without soil load in rinse water (p<0.001). Thus, chlorine-based methods may offer a benefit of reducing persistence in rinse water. We recommend responders use the most practical handwashing method to ensure hand hygiene in Ebola contexts, considering the potential benefit of chlorine-based methods in rinse water persistence.

Chemical evaluation of soil-solution in acid forest soils

USGS Publications Warehouse

Lawrence, G.B.; David, M.B.

1996-01-01

Soil-solution chemistry is commonly studied in forests through the use of soil lysimeters.This approach is impractical for regional survey studies, however, because lysimeter installation and operation is expensive and time consuming. To address these problems, a new technique was developed to compare soil-solution chemistry among red spruce stands in New York, Vermont, New Hampshire, Maine. Soil solutions were expelled by positive air pressure from soil that had been placed in a sealed cylinder. Before the air pressure was applied, a solution chemically similar to throughfall was added to the soil to bring it to approximate field capacity. After the solution sample was expelled, the soil was removed from the cylinder and chemically analyzed. The method was tested with homogenized Oa and Bs horizon soils collected from a red spruce stand in the Adirondack Mountains of New York, a red spruce stand in east-central Vermont, and a mixed hardwood stand in the Catskill Mountains of New York. Reproducibility, effects of varying the reaction time between adding throughfall and expelling soil solution (5-65 minutes) and effects of varying the chemical composition of added throughfall, were evaluated. In general, results showed that (i) the method was reproducible (coefficients of variation were generally < 15%), (ii) variations in the length of reaction-time did not affect expelled solution concentrations, and (iii) adding and expelling solution did not cause detectable changes in soil exchange chemistry. Concentrations of expelled solutions varied with the concentrations of added throughfall; the lower the CEC, the more sensitive expelled solution concentrations were to the chemical concentrations of added throughfall. Addition of a tracer (NaBr) showed that the expelled solution was a mixture of added solution and solution that preexisted in the soil. Comparisons of expelled solution concentrations with concentrations of soil solutions collected by zero-tension and tension lysimetry indicated that expelled solution concentrations were higher than those obtained with either type of lysimeter, although there was less difference with tension lysimeters than zero-tension lysimeters. The method used for collection of soil solution should be taken into consideration whenever soil solution data are being interpreted.

Methods of measuring radioactivity in the environment

NASA Astrophysics Data System (ADS)

Isaksson, Mats

In this thesis a variety of sampling methods have been utilised to assess the amount of deposited activity, mainly of 137Cs, from the Chernobyl accident and from the nuclear weapons tests. Starting with the Chernobyl accident in 1986 sampling of air and rain was used to determine the composition and amount of radioactive debris from this accident, brought to southern Sweden by the weather systems. The resulting deposition and its removal from urban areas was than studied through measurements on sewage sludge and water. The main part of the thesis considers methods of determining the amount of radiocaesium in the ground through soil sampling. In connection with soil sampling a method of optimising the sampling procedure has been developed and tested in the areas of Sweden which have a comparatively high amount of 137Cs from the Chernobyl accident. This method was then used in a survey of the activity in soil in Lund and Skane, divided between nuclear weapons fallout and fallout from the Chernobyl accident. By comparing the results from this survey with deposition calculated from precipitation measurements it was found possible to predict the deposition pattern over Skane for both nuclear weapons fallout and fallout from the Chernobyl accident. In addition, the vertical distribution of 137Cs has been modelled and the temporal variation of the depth distribution has been described.

Electrical resisitivity of mechancially stablized earth wall backfill

NASA Astrophysics Data System (ADS)

Snapp, Michael; Tucker-Kulesza, Stacey; Koehn, Weston

2017-06-01

Mechanically stabilized earth (MSE) retaining walls utilized in transportation projects are typically backfilled with coarse aggregate. One of the current testing procedures to select backfill material for construction of MSE walls is the American Association of State Highway and Transportation Officials standard T 288: ;Standard Method of Test for Determining Minimum Laboratory Soil Resistivity.; T 288 is designed to test a soil sample's electrical resistivity which correlates to its corrosive potential. The test is run on soil material passing the No. 10 sieve and believed to be inappropriate for coarse aggregate. Therefore, researchers have proposed new methods to measure the electrical resistivity of coarse aggregate samples in the laboratory. There is a need to verify that the proposed methods yield results representative of the in situ conditions; however, no in situ measurement of the electrical resistivity of MSE wall backfill is established. Electrical resistivity tomography (ERT) provides a two-dimensional (2D) profile of the bulk resistivity of backfill material in situ. The objective of this study was to characterize bulk resistivity of in-place MSE wall backfill aggregate using ERT. Five MSE walls were tested via ERT to determine the bulk resistivity of the backfill. Three of the walls were reinforced with polymeric geogrid, one wall was reinforced with metallic strips, and one wall was a gravity retaining wall with no reinforcement. Variability of the measured resistivity distribution within the backfill may be a result of non-uniform particle sizes, thoroughness of compaction, and the presence of water. A quantitative post processing algorithm was developed to calculate mean bulk resistivity of in-situ backfill. Recommendations of the study were that the ERT data be used to verify proposed testing methods for coarse aggregate that are designed to yield data representative of in situ conditions. A preliminary analysis suggests that ERT may be utilized as construction quality assurance for thoroughness of compaction in MSE construction; however more data are needed at this time.

Selected Hydrologic Applications of LANDSAT-2 Data: an Evaluation. [Snowmelt in the American River Basin and soil moisture studies at the Phoenix, Arizona Test Site and at Luverne, Minnesota

NASA Technical Reports Server (NTRS)

Wiesnet, D. R.; Mcginnis, D. F., Jr.; Matson, M. (Principal Investigator)

1978-01-01

The author has identified the following significant results. Estimates of soil moisture were obtained from visible, near-IR gamma ray and microwave data. Attempts using GOES thermal-IR were unsuccessful due to resolutions (8 km). Microwaves were the most effective at soil moisture estimates, with and without vegetative cover. Gamma rays provided only one value for the test site, produced by many data points obtained from overlapping 150 meter diameter circles. Even though the resulting averaged value was near the averaged field moisture value, this method suffers from atmospheric contaminants, the need to fly at low altitudes, and the necessity of prior calibration of a given site. Visible and near-IR relationships are present for bare fields but appear to be limited to soil moisture levels between 5 and 20%. The densely vegetated alfalfa fields correlated with near-IR reflectance only; soil moisture values from wheat fields showed no relation to either or near-IR MSS data.

Field wind tunnel testing of two silt loam soils on the North American Central High Plains

NASA Astrophysics Data System (ADS)

Scott Van Pelt, R.; Baddock, Matthew C.; Zobeck, Ted M.; Schlegel, Alan J.; Vigil, Merle F.; Acosta-Martinez, Veronica

2013-09-01

Wind erosion is a soil degrading process that threatens agricultural sustainability and environmental quality globally. Protecting the soil surface with cover crops and plant residues, practices common in no-till and reduced tillage cropping systems, are highly effective methods for shielding the soil surface from the erosive forces of wind and have been credited with beneficial increases of chemical and physical soil properties including soil organic matter, water holding capacity, and wet aggregate stability. Recently, advances in biofuel technology have made crop residues valuable feed stocks for ethanol production. Relatively little is known about cropping systems effects on intrinsic soil erodibility, the ability of the soil without a protective cover to resist the erosive force of wind. We tested the bare, uniformly disturbed, surface of long-term tillage and crop rotation research plots containing silt loam soils in western Kansas and eastern Colorado with a portable field wind tunnel. Total Suspended Particulate (TSP) were measured using glass fiber filters and respirable dust, PM10 and PM2.5, were measured using optical particle counters sampling the flow to the filters. The results were highly variable and TSP emission rates varied from less than 0.5 mg m-2 s-1 to greater than 16.1 mg m-2 s-1 but all the results indicated that cropping system history had no effect on intrinsic erodibility or dust emissions from the soil surfaces. We conclude that prior best management practices will not protect the soil from the erosive forces of wind if the protective mantle of crop residues is removed.

Humus-assisted cleaning of heavy metal contaminated soils

NASA Astrophysics Data System (ADS)

Borggaard, Ole K.; Rasmussen, Signe B.

2016-04-01

Contamination of soils with non-degradable heavy metals (HMs) because of human acticities is globally a serious problem threatening human health and ecosystem functioning. To avoid negative effects, HMs must be removed either on-site by plant uptake (phytoremediation) or off-site by extraction (soil washing). In both strategies, HM solubility must be augmented by means of a strong ligand (complexant). Often polycarboxylates such as EDTA and NTA are used but these ligands are toxic, synthetic (non-natural) and may promote HM leaching. Instead naturally occurring soluble humic substances (HS) were tested as means for cleaning HM contaminated soils; HS samples from beech and spruce litter, compost percolate and processed cow slurry were tested. Various long-term HM contaminated soils were extracted with solutions of EDTA, NTA or HS at different pH by single-step and multiple-step extraction mode. The results showed that each of the three complexant types increased HM solubility but the pH-dependent HM extraction efficiency decreased in the order: EDTA ≈ NTA > HS. However, the naturally occurring HS seems suitable for cleaning As, Cd, Cu and Zn contaminated soils both in relation to phytoremediation of moderately contaminated soils and washing of strongly contaminated soils. On the other hand, HS was found unsuited as cleaning agent for Pb polluted calcareous soils. If future field experiments confirm these laboratory results, we have a new cheap and environmentally friendly method for solving a great pollution problem, i.e. cleaning of heavy metal contaminated soils. In addition, humic substances possess additional benefits such as improving soil structure and stimulating microbial activity.

Assessment of soil biological quality index (QBS-ar) in different crop rotation systems in paddy soils

NASA Astrophysics Data System (ADS)

Nadimi-Goki, Mandana; Bini, Claudio; haefele, Stephan

2013-04-01

New methods, based on soil microarthropods for soil quality evaluation have been proposed by some Authors. Soil microarthropods demonstrated to respond sensitively to land management practices and to be correlated with beneficial soil functions. QBS Index (QBS-ar) is calculated on the basis of microarthropod groups present in a soil sample. Each biological form found in the sample receives a score from 1 to 20 (eco-morphological index, EMI), according to its adaptation to soil environment. The objective of this study was to evaluate the effect of various rotation systems and sampling periods on soil biological quality index, in paddy soils. For the purpose of this study surface soil samples (0-15 cm depth) were collected from different rotation systems (rice-rice-rice, soya-rice-rice, fallow-rice and pea-soya-rice) with three replications, and four sampling times in April (after field preparation), June (after seedling), August (after tillering stage) and October (after rice harvesting). The study area is located in paddy soils of Verona area, Northern Italy. Soil microarthropods from a total of 48 samples were extracted and classified according to the Biological Quality of Soil Index (QBS-ar) method. In addition soil moisture, Cumulative Soil Respiration and pH were measured in each site. More diversity of microarthropod groups was found in June and August sampling times. T-test results between different rotations did not show significant differences while the mean difference between rotation and different sampling times is statistically different. The highest QBS-ar value was found in the fallow-rice rotation in the forth soil sampling time. Similar value was found in soya-rice-rice rotation. Result of linear regression analysis indicated that there is significant correlation between QBS-ar values and Cumulative Soil Respiration. Keywords: soil biological quality index (QBS-ar), Crop Rotation System, paddy soils, Italy

An update on remote measurement of soil moisture over vegetation using infrared temperature measurements: A FIFE perspective

NASA Technical Reports Server (NTRS)

Carlson, Toby N.

1988-01-01

Using model development, image analysis and micrometeorological measurements, the object is to push beyond the present limitations of using the infrared temperature method for remotely determining surface energy fluxes and soil moisture over vegetation. Model development consists of three aspects: (1) a more complex vegetation formulation which is more flexible and realistic; (2) a method for modeling the fluxes over patchy vegetation cover; and (3) a method for inferring a two-layer soil vertical moisture gradient from analyses of horizontal variations in surface temperatures. HAPEX and FIFE satellite data will be used along with aircraft thermal infrared and solar images as input for the models. To test the models, moisture availability and bulk canopy resistances will be calculated from data collected locally at the Rock Springs experimental field site and, eventually, from the FIFE project.

An Experimental and Modeling Study of Evaporation from Bare Soils Subjected to Natural Boundary Conditions at the Land-Atmospheric Interface

NASA Astrophysics Data System (ADS)

Smits, K. M.; Ngo, V. V.; Cihan, A.; Sakaki, T.; Illangasekare, T. H.; kathleen m smits

2011-12-01

Bare soil evaporation is a key process for water exchange between the land and the atmosphere and an important component of the water balance in semiarid and arid regions. However, there is no agreement on the best methodology to determine evaporation under different boundary conditions. Because it is difficult to measure evaporation from soil,with the exception of using lysimeters, numerous formulations have been proposed to establish a relationship between the rate of evaporation and soil moisture and/or soil temperature and thermal properties. Different formulations vary in how they partition available energy and include, among others, a classical bulk aerodynamic formulation which requires knowledge of the relative humidity at the soil surface and a more non-traditional heat balance method which requires knowledge of soil temperature and soil thermal properties. A need exists to systematically compare existing methods to experimental data under highly controlled conditions not achievable in the field. The goal of this work is to perform controlled experiments under transient conditions of soil moisture, temperature and wind at the land/atmospheric interface to test different conceptual and mathematical formulations for evaporation rate estimates and to develop appropriate numerical models to be used in simulations. In this study, to better understand the coupled water-vapor-heat flow processes in the shallow subsurface near the land surface, we modified a previously developed theory that allows non-equilibrium liquid/gas phase change with gas phase vapor diffusion to better account for evaporation under dry soil conditions. This theory was used to compare estimates of evaporation based on different formulations of the bulk aerodynamic and heat balance methods. In order to experimentally validate the numerical formulations/code, we performed a series of two-dimensional physical model experiments under varying boundary conditions using test sand for which the hydraulic and thermal properties were well characterized. We developed a unique two dimensional cell apparatus equipped with a network of sensors for automated and continuous monitoring of soil moisture, soil and air temperature and relative humidity, and wind velocity. Precision data under well-controlled transient heat and wind boundary conditions was generated. Results from numerical simulations were compared with experimental data. Results demonstrate the importance of properly characterizing soil thermal properties and accounting for dry soil conditions to properly estimate evaporation. Initial comparisons of various formulations of evaporation demonstrate the need for joint evaluation of heat and mass transfer for better modeling accuracy. Detailed comparisons are still underway. This knowledge is applicable to many current hydrologic and environmental problems to include climate modeling and the simulation of contaminant transport and volatilization in the shallow subsurface.

Tree stability under wind: simulating uprooting with root breakage using a finite element method

PubMed Central

Yang, Ming; Défossez, Pauline; Danjon, Frédéric; Fourcaud, Thierry

2014-01-01

Background and Aims Windstorms are the major natural hazard affecting European forests, causing tree damage and timber losses. Modelling tree anchorage mechanisms has progressed with advances in plant architectural modelling, but it is still limited in terms of estimation of anchorage strength. This paper aims to provide a new model for root anchorage, including the successive breakage of roots during uprooting. Methods The model was based on the finite element method. The breakage of individual roots was taken into account using a failure law derived from previous work carried out on fibre metal laminates. Soil mechanical plasticity was considered using the Mohr–Coulomb failure criterion. The mechanical model for roots was implemented in the numerical code ABAQUS using beam elements embedded in a soil block meshed with 3-D solid elements. The model was tested by simulating tree-pulling experiments previously carried out on a tree of Pinus pinaster (maritime pine). Soil mechanical parameters were obtained from laboratory tests. Root system architecture was digitized and imported into ABAQUS while root material properties were estimated from the literature. Key Results Numerical simulations of tree-pulling tests exhibited realistic successive root breakages during uprooting, which could be seen in the resulting response curves. Broken roots could be visually located within the root system at any stage of the simulations. The model allowed estimation of anchorage strength in terms of the critical turning moment and accumulated energy, which were in good agreement with in situ measurements. Conclusions This study provides the first model of tree anchorage strength for P. pinaster derived from the mechanical strength of individual roots. The generic nature of the model permits its further application to other tree species and soil conditions. PMID:25006178

Practical estimates of field-saturated hydraulic conductivity of bedrock outcrops using a modified bottomless bucket method

USGS Publications Warehouse

Mirus, Benjamin B.; Perkins, Kim S.

2012-01-01

The bottomless bucket (BB) approach (Nimmo et al., 2009a) is a cost-effective method for rapidly characterizing field-saturated hydraulic conductivity Kfs of soils and alluvial deposits. This practical approach is of particular value for quantifying infiltration rates in remote areas with limited accessibility. A similar approach for bedrock outcrops is also of great value for improving quantitative understanding of infiltration and recharge in rugged terrain. We develop a simple modification to the BB method for application to bedrock outcrops, which uses a non-toxic, quick-drying silicone gel to seal the BB to the bedrock. These modifications to the field method require only minor changes to the analytical solution for calculating Kfs on soils. We investigate the reproducibility of the method with laboratory experiments on a previously studied calcarenite rock and conduct a sensitivity analysis to quantify uncertainty in our predictions. We apply the BB method on both bedrock and soil for sites on Pahute Mesa, which is located in a remote area of the Nevada National Security Site. The bedrock BB tests may require monitoring over several hours to days, depending on infiltration rates, which necessitates a cover to prevent evaporative losses. Our field and laboratory results compare well to Kfs values inferred from independent reports, which suggests the modified BB method can provide useful estimates and facilitate simple hypothesis testing. The ease with which the bedrock BB method can be deployed should facilitate more rapid in-situ data collection than is possible with alternative methods for quantitative characterization of infiltration into bedrock.

Measurement of particle size distribution of soil and selected aggregate sizes using the hydrometer method and laser diffractometry

NASA Astrophysics Data System (ADS)

Guzmán, G.; Gómez, J. A.; Giráldez, J. V.

2010-05-01

Soil particle size distribution has been traditionally determined by the hydrometer or the sieve-pipette methods, both of them time consuming and requiring a relatively large soil sample. This might be a limitation in situations, such as for instance analysis of suspended sediment, when the sample is small. A possible alternative to these methods are the optical techniques such as laser diffractometry. However the literature indicates that the use of this technique as an alternative to traditional methods is still limited, because the difficulty in replicating the results obtained with the standard methods. In this study we present the percentages of soil grain size determined using laser diffractometry within ranges set between 0.04 - 2000 μm. A Beckman-Coulter ® LS-230 with a 750 nm laser beam and software version 3.2 in five soils, representative of southern Spain: Alameda, Benacazón, Conchuela, Lanjarón and Pedrera. In three of the studied soils (Alameda, Benacazón and Conchuela) the particle size distribution of each aggregate size class was also determined. Aggregate size classes were obtained by dry sieve analysis using a Retsch AS 200 basic ®. Two hundred grams of air dried soil were sieved during 150 s, at amplitude 2 mm, getting nine different sizes between 2000 μm and 10 μm. Analyses were performed by triplicate. The soil sample preparation was also adapted to our conditions. A small amount each soil sample (less than 1 g) was transferred to the fluid module full of running water and disaggregated by ultrasonication at energy level 4 and 80 ml of sodium hexametaphosphate solution during 580 seconds. Two replicates of each sample were performed. Each measurement was made for a 90 second reading at a pump speed of 62. After the laser diffractometry analysis, each soil and its aggregate classes were processed calibrating its own optical model fitting the optical parameters that mainly depends on the color and the shape of the analyzed particle. As a second alternative a unique optical model valid for a broad range of soils developed by the Department of Soil, Water, and Environmental Science of the University of Arizona (personal communication, already submitted) was tested. The results were compared with the particle size distribution measured in the same soils and aggregate classes using the hydrometer method. Preliminary results indicate a better calibration of the technique using the optical model of the Department of Soil, Water, and Environmental Science of the University of Arizona, which obtained a good correlations (r2>0.85). This result suggests that with an appropriate calibration of the optical model laser diffractometry might provide a reliable soil particle characterization.

Trace metal mobilization by organic soil amendments: insights gained from analyses of solid and solution phase complexation of cadmium, nickel and zinc.

PubMed

Welikala, Dharshika; Hucker, Cameron; Hartland, Adam; Robinson, Brett H; Lehto, Niklas J

2018-05-01

The accumulation of Cd in soils worldwide has increased the demand for methods to reduce the metal's plant bioavailability. Organic matter rich soil amendments have been shown to be effective in achieving this. However, it is not known how long these amendments can retain the Cd, and whether dissolved organic matter (DOM) released from them can enhance the metal's mobility in the environment. In this study we sought to test the Cd binding capacity of various organic soil amendments, and evaluate differences in characteristics of the DOM released to see if they can explain the lability of the Cd-DOM complexes. We collected ten organic soil amendments from around New Zealand: five different composts, biosolids from two sources, two types of peat and spent coffee grounds. We characterised the amendments' elemental composition and their ability to bind the Cd. We then selected two composts and two peats for further tests, where we measured the sorption of Ni or Zn by the amendments. We analysed the quality of the extracted DOM from the four amendments using 3D Excitation Emission Matrix analysis, and tested the lability of the metal-DOM complexes using an adapted diffusive gradients in thin-films (DGT) method. We found that composts bound the most Cd and that the emergent Cd-DOM complexes were less labile than those from the peats. Ni-DOM complexes were the least labile. The aromaticity of the extracted DOM appears to be an important factor in determining the lability of Ni complexes, but less so for Zn and Cd. Copyright © 2018 Elsevier Ltd. All rights reserved.

Integration of Biomass Harvesting and Site Preparation

Treesearch

Bryce J. Stokes; William F. Watson

1986-01-01

This study was conducted to assess the costs of various site preparation methods with various levels of harvesting Site impacts, soil compaction and disturbance were examined. Three hawesting methods rare evaluated in pine pulpwood plantation and pine sawtimber stands. The harvesting methods tested were (1) conventional - harvesting all roundwood. (2) two-pass - first...

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

Not Available

This report was prepared at the request of the Lawrence Livermore Laboratory (LLL) to provide background information for analyzing soil-structure interaction by the frequency-independent impedance function approach. LLL is conducting such analyses as part of its seismic review of selected operating plants under the Systematic Evaluation Program for the US Nuclear Regulatory Commission. The analytical background and basic assumptionsof the impedance function theory are briefly reviewed, and the role of radiation damping in soil-structure interaction analysis is discussed. The validity of modeling soil-structure interaction by using frequency-independent functions is evaluated based on data from several field tests. Finally, the recommendedmore » procedures for performing soil-structure interaction analyses are discussed with emphasis on the modal superposition method.« less

From patterns to causal understanding: Structural equation modeling (SEM) in soil ecology

USGS Publications Warehouse

Eisenhauer, Nico; Powell, Jeff R; Grace, James B.; Bowker, Matthew A.

2015-01-01

In this perspectives paper we highlight a heretofore underused statistical method in soil ecological research, structural equation modeling (SEM). SEM is commonly used in the general ecological literature to develop causal understanding from observational data, but has been more slowly adopted by soil ecologists. We provide some basic information on the many advantages and possibilities associated with using SEM and provide some examples of how SEM can be used by soil ecologists to shift focus from describing patterns to developing causal understanding and inspiring new types of experimental tests. SEM is a promising tool to aid the growth of soil ecology as a discipline, particularly by supporting research that is increasingly hypothesis-driven and interdisciplinary, thus shining light into the black box of interactions belowground.

Evaluating Soil Health Using Remotely Sensed Evapotranspiration on the Benchmark Barnes Soils of North Dakota

NASA Astrophysics Data System (ADS)

Bohn, Meyer; Hopkins, David; Steele, Dean; Tuscherer, Sheldon

2017-04-01

The benchmark Barnes soil series is an extensive upland Hapludoll of the northern Great Plains that is both economically and ecologically vital to the region. Effects of tillage erosion coupled with wind and water erosion have degraded Barnes soil quality, but with unknown extent, distribution, or severity. Evidence of soil degradation documented for a half century warrants that the assumption of productivity be tested. Soil resilience is linked to several dynamic soil properties and National Cooperative Soil Survey initiatives are now focused on identifying those properties for benchmark soils. Quantification of soil degradation is dependent on a reliable method for broad-scale evaluation. The soil survey community is currently developing rapid and widespread soil property assessment technologies. Improvements in satellite based remote-sensing and image analysis software have stimulated the application of broad-scale resource assessment. Furthermore, these technologies have fostered refinement of land-based surface energy balance algorithms, i.e. Mapping Evapotranspiration at High Resolution with Internalized Calibration (METRIC) algorithm for evapotranspiration (ET) mapping. The hypothesis of this study is that ET mapping technology can differentiate soil function on extensive landscapes and identify degraded areas. A recent soil change study in eastern North Dakota resampled legacy Barnes pedons sampled prior to 1960 and found significant decreases in organic carbon. An ancillary study showed that evapotranspiration (ET) estimates from METRIC decreased with Barnes erosion class severity. An ET raster map has been developed for three eastern North Dakota counties using METRIC and Landsat 5 imagery. ET pixel candidates on major Barnes soil map units were stratified into tertiles and classified as ranked ET subdivisions. A sampling population of randomly selected points stratified by ET class and county proportion was established. Morphologic and chemical data will be recorded at each sampling site to test whether soil properties correlate to ET, thus serving as a non-biased proxy for soil health.

Soil moisture sensors for continuous monitoring

USGS Publications Warehouse

Amer, Saud A.; Keefer, T. O.; Weltz, M.A.; Goodrich, David C.; Bach, Leslie

1995-01-01

Certain physical and chemical properties of soil vary with soil water content. The relationship between these properties and water content is complex and involves both the pore structure and constituents of the soil solution. One of the most economical techniques to quantify soil water content involves the measurement of electrical resistance of a dielectric medium that is in equilibrium with the soil water content. The objective of this research was to test the reliability and accuracy of fiberglass soil-moisture electrical resistance sensors (ERS) as compared to gravimetric sampling and Time Domain Reflectometry (TDR). The response of the ERS was compared to gravimetric measurements at eight locations on the USDA-ABS Walnut Gulch Experimental Watershed. The comparisons with TDR sensors were made at three additional locations on the same watershed. The high soil rock content (>45 percent) at seven locations resulted in consistent overestimation of soil water content by the ERS method. Where rock content was less than 10 percent, estimation of soil water was within 5 percent of the gravimetric soil water content. New methodology to calibrate the ERS sensors for rocky soils will need to be developed before soil water content values can be determined with these sensors. (KEY TERMS: soil moisture; soil water; infiltration; instrumentation; soil moisture sensors.)

Geochemical and mineralogical data for soils of the conterminous United States

USGS Publications Warehouse

Smith, David B.; Cannon, William F.; Woodruff, Laurel G.; Solano, Federico; Kilburn, James E.; Fey, David L.

2013-01-01

In 2007, the U.S. Geological Survey initiated a low-density (1 site per 1,600 square kilometers, 4,857 sites) geochemical and mineralogical survey of soils of the conterminous United States as part of the North American Soil Geochemical Landscapes Project. Sampling and analytical protocols were developed at a workshop in 2003, and pilot studies were conducted from 2004 to 2007 to test and refine these recommended protocols. The final sampling protocol for the national-scale survey included, at each site, a sample from a depth of 0 to 5 centimeters, a composite of the soil A horizon, and a deeper sample from the soil C horizon or, if the top of the C horizon was at a depth greater than 1 meter, from a depth of approximately 80–100 centimeters. The <2-millimeter fraction of each sample was analyzed for a suite of 45 major and trace elements by methods that yield the total or near-total elemental content. The major mineralogical components in the samples from the soil A and C horizons were determined by a quantitative X-ray diffraction method using Rietveld refinement. Sampling in the conterminous United States was completed in 2010, with chemical and mineralogical analyses completed in May 2013. The resulting dataset provides an estimate of the abundance and spatial distribution of chemical elements and minerals in soils of the conterminous United States and represents a baseline for soil geochemistry and mineralogy against which future changes may be recognized and quantified. This report (1) describes the sampling, sample preparation, and analytical methods used; (2) gives details of the quality control protocols used to monitor the quality of chemical and mineralogical analyses over approximately six years; and (3) makes available the soil geochemical and mineralogical data in downloadable tables.

Arsenic Speciation and Extraction and the Significance of Biodegradable Acid on Arsenic Removal—An Approach for Remediation of Arsenic-Contaminated Soil

PubMed Central

Nguyen Van, Thinh; Osanai, Yasuhito; Do Nguyen, Hai; Kurosawa, Kiyoshi

2017-01-01

A series of arsenic remediation tests were conducted using a washing method with biodegradable organic acids, including oxalic, citric and ascorbic acids. Approximately 80% of the arsenic in one sample was removed under the effect of the ascorbic and oxalic acid combination, which was roughly twice higher than the effectiveness of the ascorbic and citric acid combination under the same conditions. The soils treated using biodegradable acids had low remaining concentrations of arsenic that are primarily contained in the crystalline iron oxides and organic matter fractions. The close correlation between extracted arsenic and extracted iron/aluminum suggested that arsenic was removed via the dissolution of Fe/Al oxides in soils. The fractionation of arsenic in four contaminated soils was investigated using a modified sequential extraction method. Regarding fractionation, we found that most of the soil contained high proportions of arsenic (As) in exchangeable fractions with phosphorus, amorphous oxides, and crystalline iron oxides, while a small amount of the arsenic fraction was organic matter-bound. This study indicated that biodegradable organic acids can be considered as a means for arsenic-contaminated soil remediation.

Theoretical and experimental analysis of an equivalent circuit model for the investigation of shallow landmines with acoustic methods

NASA Astrophysics Data System (ADS)

Borgioli, G.; Bulletti, A.; Calzolai, M.; Capineri, L.; Falorni, P.; Masotti, L.; Valentini, S.; Windsor, C.

2007-10-01

Acoustic methods have been recently investigated for the detection of shallow landmines. Some plastic landmines have a flexible case which can made to vibrate by an airborne excitation like a loudspeaker. The soil-mine system shows a resonant behavior which is used as a signature to discriminate from other rigid objects. The mechanical resonance can be detected at the soil surface by a remote sensing systems like a laser interferometer. An equivalent physical model of the mine-soil system has been investigated having the known physical characteristics of mine simulants. The authors designed and built a test-object with known mechanical characteristics (mass, elasticity, damping factor). The model has been characterized in laboratory and the results compared with the classic mass-spring loss oscillator described by Voigt. The vibrations at the soil surface have been measured in various positions with a micro machined accelerometer. The results of the simulations for the acceleration of the soil-mine system agree well with the experiment. The calibrated mine model is useful to investigate the variation of the resonance frequency for various buried depths and to compare the results for different soils in different environmental conditions.

Assessment of cyanide contamination in soils with a handheld mid-infrared spectrometer.

PubMed

Soriano-Disla, José M; Janik, Leslie J; McLaughlin, Michael J

2018-02-01

We examined the feasibility of using handheld mid-infrared (MIR) Fourier-Transform infrared (FT-IR) instrumentation for detecting and analysing cyanide (CN) contamination in field contaminated soils. Cyanide spiking experiments were first carried out, in the laboratory, to test the sensitivity of infrared Fourier transform (DRIFT) spectrometry to ferro- and ferricyanide compounds across a range of reference soils and minerals. Both benchtop and handheld diffuse reflectance infrared spectrometers were tested. Excellent results were obtained for the reference soils and minerals, with the MIR outperforming the near-infrared (NIR) range. Spectral peaks characteristic of the -C≡N group were observed near 2062 and 2118cm -1 in the MIR region for the ferro- and ferricyanide compounds spiked into soils/minerals, respectively. In the NIR region such peaks were observed near 4134 and 4220cm -1 . Cyanide-contaminated samples were then collected in the field and analyzed with the two spectrometers to further test the applicability of the DRIFT technique for soils containing aged CN residues. The prediction of total CN in dry and ground contaminated soils using the handheld MIR instrument resulted in a coefficient of determination (R 2 ) of 0.88-0.98 and root mean square error of the cross-validation (RMSE) of 21-49mgkg -1 for a CN range of 0-611mgkg -1 . A major peak was observed in the MIR at about 2092cm -1 which was attributed to "Prussian Blue" (Fe 4 [Fe(CN) 6 ] 3 ·xH 2 O). These results demonstrate the potential of handheld DRIFT instrumentation as a promising alternative to the standard laboratory method to predict CN concentrations in contaminated field soils. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Comparison of spatial interpolation methods for soil moisture and its application for monitoring drought.

PubMed

Chen, Hui; Fan, Li; Wu, Wei; Liu, Hong-Bin

2017-09-26

Soil moisture data can reflect valuable information on soil properties, terrain features, and drought condition. The current study compared and assessed the performance of different interpolation methods for estimating soil moisture in an area with complex topography in southwest China. The approaches were inverse distance weighting, multifarious forms of kriging, regularized spline with tension, and thin plate spline. The 5-day soil moisture observed at 167 stations and daily temperature recorded at 33 stations during the period of 2010-2014 were used in the current work. Model performance was tested with accuracy indicators of determination coefficient (R 2 ), mean absolute percentage error (MAPE), root mean square error (RMSE), relative root mean square error (RRMSE), and modeling efficiency (ME). The results indicated that inverse distance weighting had the best performance with R 2 , MAPE, RMSE, RRMSE, and ME of 0.32, 14.37, 13.02%, 0.16, and 0.30, respectively. Based on the best method, a spatial database of soil moisture was developed and used to investigate drought condition over the study area. The results showed that the distribution of drought was characterized by evidently regional difference. Besides, drought mainly occurred in August and September in the 5 years and was prone to happening in the western and central parts rather than in the northeastern and southeastern areas.

Investigation of Expedient Ground Surfacing with a Glass Fiber-Resin Mixture by a Spray-Deposition Technique,

DTIC Science & Technology

PAVEMENTS, *REINFORCED PLASTICS), LANDING FIELDS, SPRAYS, GLASS TEXTILES, LAMINATED PLASTICS, TEST METHODS, FOUNDATIONS(STRUCTURES), SANDWICH CONSTRUCTION, SOILS, FEASIBILITY STUDIES, LOAD DISTRIBUTION

Development, optimization, validation and application of faster gas chromatography - flame ionization detector method for the analysis of total petroleum hydrocarbons in contaminated soils.

PubMed

Zubair, Abdulrazaq; Pappoe, Michael; James, Lesley A; Hawboldt, Kelly

2015-12-18

This paper presents an important new approach to improving the timeliness of Total Petroleum Hydrocarbon (TPH) analysis in the soil by Gas Chromatography - Flame Ionization Detector (GC-FID) using the CCME Canada-Wide Standard reference method. The Canada-Wide Standard (CWS) method is used for the analysis of petroleum hydrocarbon compounds across Canada. However, inter-laboratory application of this method for the analysis of TPH in the soil has often shown considerable variability in the results. This could be due, in part, to the different gas chromatography (GC) conditions, other steps involved in the method, as well as the soil properties. In addition, there are differences in the interpretation of the GC results, which impacts the determination of the effectiveness of remediation at hydrocarbon-contaminated sites. In this work, multivariate experimental design approach was used to develop and validate the analytical method for a faster quantitative analysis of TPH in (contaminated) soil. A fractional factorial design (fFD) was used to screen six factors to identify the most significant factors impacting the analysis. These factors included: injection volume (μL), injection temperature (°C), oven program (°C/min), detector temperature (°C), carrier gas flow rate (mL/min) and solvent ratio (v/v hexane/dichloromethane). The most important factors (carrier gas flow rate and oven program) were then optimized using a central composite response surface design. Robustness testing and validation of model compares favourably with the experimental results with percentage difference of 2.78% for the analysis time. This research successfully reduced the method's standard analytical time from 20 to 8min with all the carbon fractions eluting. The method was successfully applied for fast TPH analysis of Bunker C oil contaminated soil. A reduced analytical time would offer many benefits including an improved laboratory reporting times, and overall improved clean up efficiency. The method was successfully applied for the analysis of TPH of Bunker C oil in contaminated soil. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Development of Mackintosh Probe Extractor

NASA Astrophysics Data System (ADS)

Rahman, Noor Khazanah A.; Kaamin, Masiri; Suwandi, Amir Khan; Sahat, Suhaila; Jahaya Kesot, Mohd

2016-11-01

Dynamic probing is a continuous soil investigation technique, which is one of the simplest soil penetration test. It basically consist of repeatedly driving a metal tipped probe into the ground using a drop weight of fixed mass and travel. Testing was carried out continuously from ground level to the final penetration depth. Once the soil investigation work done, it is difficult to pull out the probe rod from the ground, due to strong soil structure grip against probe cone and prevent the probe rod out from the ground. Thus, in this case, a tool named Extracting Probe was created to assist in the process of retracting the probe rod from the ground. In addition, Extracting Probe also can reduce the time to extract the probe rod from the ground compare with the conventional method. At the same time, it also can reduce manpower cost because only one worker involve to handle this tool compare with conventional method used two or more workers. From experiment that have been done we found that the time difference between conventional tools and extracting probe is significant, average time difference is 155 minutes. In addition the extracting probe can reduce manpower usage, and also labour cost for operating the tool. With all these advantages makes this tool has the potential to be marketed.

Short term spatio-temporal variability of soil water-extractable calcium and magnesium after a low severity grassland fire in Lithuania.

NASA Astrophysics Data System (ADS)

Pereira, Paulo; Martin, David

2014-05-01

Fire has important impacts on soil nutrient spatio-temporal distribution (Outeiro et al., 2008). This impact depends on fire severity, topography of the burned area, type of soil and vegetation affected, and the meteorological conditions post-fire. Fire produces a complex mosaic of impacts in soil that can be extremely variable at small plot scale in the space and time. In order to assess and map such a heterogeneous distribution, the test of interpolation methods is fundamental to identify the best estimator and to have a better understanding of soil nutrients spatial distribution. The objective of this work is to identify the short-term spatial variability of water-extractable calcium and magnesium after a low severity grassland fire. The studied area is located near Vilnius (Lithuania) at 54° 42' N, 25° 08 E, 158 masl. Four days after the fire, it was designed in a burned area a plot with 400 m2 (20 x 20 m with 5 m space between sampling points). Twenty five samples from top soil (0-5 cm) were collected immediately after the fire (IAF), 2, 5, 7 and 9 months after the fire (a total of 125 in all sampling dates). The original data of water-extractable calcium and magnesium did not respected the Gaussian distribution, thus a neperian logarithm (ln) was applied in order to normalize data. Significant differences of water-extractable calcium and magnesium among sampling dates were carried out with the Anova One-way test using the ln data. In order to assess the spatial variability of water-extractable calcium and magnesium, we tested several interpolation methods as Ordinary Kriging (OK), Inverse Distance to a Weight (IDW) with the power of 1, 2, 3 and 4, Radial Basis Functions (RBF) - Inverse Multiquadratic (IMT), Multilog (MTG), Multiquadratic (MTQ) Natural Cubic Spline (NCS) and Thin Plate Spline (TPS) - and Local Polynomial (LP) with the power of 1 and 2. Interpolation tests were carried out with Ln data. The best interpolation method was assessed using the cross validation method. Cross-validation was obtained by taking each observation in turn out of the sample pool and estimating from the remaining ones. The errors produced (observed-predicted) are used to evaluate the performance of each method. With these data, the mean error (ME) and root mean square error (RMSE) were calculated. The best method was the one which had the lower RMSE (Pereira et al. in press). The results shown significant differences among sampling dates in the water-extractable calcium (F= 138.78, p< 0.001) and extractable magnesium (F= 160.66; p< 0.001). Water-extractable calcium and magnesium was high IAF decreasing until 7 months after the fire, rising in the last sampling date. Among the tested methods, the most accurate to interpolate the water-extractable calcium were: IAF-IDW1; 2 Months-IDW1; 5 months-OK; 7 Months-IDW4 and 9 Months-IDW3. In relation to water-extractable magnesium the best interpolation techniques were: IAF-IDW2; 2 Months-IDW1; 5 months- IDW3; 7 Months-TPS and 9 Months-IDW1. These results suggested that the spatial variability of these water-extractable is variable with the time. The causes of this variability will be discussed during the presentation. References Outeiro, L., Aspero, F., Ubeda, X. (2008) Geostatistical methods to study spatial variability of soil cation after a prescribed fire and rainfall. Catena, 74: 310-320. Pereira, P., Cerdà, A., Úbeda, X., Mataix-Solera, J. Arcenegui, V., Zavala, L. Modelling the impacts of wildfire on ash thickness in a short-term period, Land Degradation and Development, (In Press), DOI: 10.1002/ldr.2195

In vitro study on the effect of doxycycline on the microbial activity of soil determined by redox-potential measuring system.

PubMed

Szakmár, Katalin; Reichart, Olivér; Szatmári, István; Erdősi, Orsolya; Szili, Zsuzsanna; László, Noémi; Székely Körmöczy, Péter; Laczay, Péter

2014-09-01

The potential effect of doxycycline on the microbial activity was investigated in three types of soil. Soil samples were spiked with doxycycline, incubated at 25°C and tested at 0, 2, 4 and 6 days after treatment. The microbiological activity of the soil was characterized by the viable count determined by plate pouring and by the time necessary to reach a defined rate of the redox-potential decrease termed as time to detection (TTD).The viable count of the samples was not changed during the storage. The TTD values, however exhibited a significant increase in the 0.2-1.6 mg/kg doxycycline concentration range compared to the untreated samples indicating concentration-dependent inhibitory effect on microbial activity. The potency of the effect was different in the 3 soil types. To describe the combined effect of the doxycycline concentration and time on the biological activity of one type of soil a mathematical model was constructed and applied.The change of microbial metabolic rate could be measured also without (detectable) change of microbial count when the traditional microbiological methods are not applicable. The applied new redox potential measurement-based method is a simple and useful procedure for the examination of microbial activity of soil and its potential inhibition by antibiotics.

Evaluation of soil water stable isotope analysis by H2O(liquid)-H2O(vapor) equilibration method

NASA Astrophysics Data System (ADS)

Gralher, Benjamin; Stumpp, Christine

2014-05-01

Environmental tracers like stable isotopes of water (δ18O, δ2H) have proven to be valuable tools to study water flow and transport processes in soils. Recently, a new technique for soil water isotope analysis has been developed that employs a vapor phase being in isothermal equilibrium with the liquid phase of interest. This has increased the potential application of water stable isotopes in unsaturated zone studies as it supersedes laborious extraction of soil water. However, uncertainties of analysis and influencing factors need to be considered. Therefore, the objective of this study was to evaluate different methodologies of analysing stable isotopes in soil water in order to reduce measurement uncertainty. The methodologies included different preparation procedures of soil cores for equilibration of vapor and soil water as well as raw data correction. Two different inflatable sample containers (freezer bags, bags containing a metal layer) and equilibration atmospheres (N2, dry air) were tested. The results showed that uncertainties for δ18O were higher compared to δ2H that cannot be attributed to any specific detail of the processing routine. Particularly, soil samples with high contents of organic matter showed an apparent isotope enrichment which is indicative for fractionation due to evaporation. However, comparison of water samples obtained from suction cups with the local meteoric water line indicated negligible fractionation processes in the investigated soils. Therefore, a method was developed to correct the raw data reducing the uncertainties of the analysis.. We conclude that the evaluated method is advantageous over traditional methods regarding simplicity, resource requirements and sample throughput but careful consideration needs to be made regarding sample handling and data processing. Thus, stable isotopes of water are still a good tool to determine water flow and transport processes in the unsaturated zone.

3D-printing of undisturbed soil imaged by X-ray

NASA Astrophysics Data System (ADS)

Bacher, Matthias; Koestel, John; Schwen, Andreas

2014-05-01

The unique pore structures in Soils are altered easily by water flow. Each sample has a different morphology and the results of repetitions vary as well. Soil macropores in 3D-printed durable material avoid erosion and have a known morphology. Therefore potential and limitations of reproducing an undisturbed soil sample by 3D-printing was evaluated. We scanned an undisturbed soil column of Ultuna clay soil with a diameter of 7 cm by micro X-ray computer tomography at a resolution of 51 micron. A subsample cube of 2.03 cm length with connected macropores was cut out from this 3D-image and printed in five different materials by a 3D-printing service provider. The materials were ABS, Alumide, High Detail Resin, Polyamide and Prime Grey. The five print-outs of the subsample were tested on their hydraulic conductivity by using the falling head method. The hydrophobicity was tested by an adapted sessile drop method. To determine the morphology of the print-outs and compare it to the real soil also the print-outs were scanned by X-ray. The images were analysed with the open source program ImageJ. The five 3D-image print-outs copied from the subsample of the soil column were compared by means of their macropore network connectivity, porosity, surface volume, tortuosity and skeleton. The comparison of pore morphology between the real soil and the print-outs showed that Polyamide reproduced the soil macropore structure best while Alumide print-out was the least detailed. Only the largest macropore was represented in all five print-outs. Printing residual material or printing aid material remained in and clogged the pores of all print-out materials apart from Prime Grey. Therefore infiltration was blocked in these print-outs and the materials are not suitable even though the 3D-printed pore shapes were well reproduced. All of the investigated materials were insoluble. The sessile drop method showed angles between 53 and 85 degrees. Prime Grey had the fastest flow rate; the other conducting materials had slow or non-reproducible flow rates. Since only Prime Grey was able to print-out the largest macropore in a discontinuous way, the morphological differences between the five print-outs were not evaluated. Each material has its limitations but only Prime Greys morphology was sufficiently printed and no clogging with residual material occurred. Polyamide and High Detail Resin had clogged pores but were matching the soil's macropore morphology better but further research on removal of residual material blocking pores is needed before they are useable.

Characterizing the phosphorus forms extracted from soil by the Mehlich III soil test

USDA-ARS?s Scientific Manuscript database

Phosphorus (P) can limit crop production in many soils, but P loss from soils may impair water quality; soil testing can guide fertilizer recommendations to optimize crop growth while minimizing P loss. The Mehlich III (M3) soil test is widely used in North America, followed by colorimetric analysis...

On-line/on-site analysis of heavy metals in water and soils by laser induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Meng, Deshuo; Zhao, Nanjing; Wang, Yuanyuan; Ma, Mingjun; Fang, Li; Gu, Yanhong; Jia, Yao; Liu, Jianguo

2017-11-01

The enrichment method of heavy metal in water with graphite and aluminum electrode was studied, and combined with plasma restraint device for improving the sensitivity of detection and reducing the limit of detection (LOD) of elements. For aluminum electrode enrichment, the LODs of Cd, Pb and Ni can be as low as several ppb. For graphite enrichment, the measurement time can be less than 3 min. The results showed that the graphite enrichment and aluminum electrode enrichment method can effectively improve the LIBS detection ability. The graphite enrichment method combined with plasma spatial confinement is more suitable for on-line monitoring of industrial waste water, the aluminum electrode enrichment method can be used for trace heavy metal detection in water. A LIBS method and device for soil heavy metals analysis was also developed, and a mobile LIBS system was tested in outfield. The measurement results deduced from LIBS and ICP-MS had a good consistency. The results provided an important application support for rapid and on-site monitoring of heavy metals in soil. (Left: the mobile LIBS system for analysis of heavy metals in soils. Top right: the spatial confinement device. Bottom right: automatic graphite enrichment device for on0line analysis of heavy metals in water).

Determining temporal scales of the soil moisture variations by Empirical Mode Decompositions and wavelet methods and its use for validation of SMOS data

NASA Astrophysics Data System (ADS)

Usowicz, Jerzy, B.; Marczewski, Wojciech; Usowicz, Boguslaw; Lipiec, Jerzy; Lukowski, Mateusz I.

2010-05-01

This paper presents the results of the time series analysis of the soil moisture observed at two test sites Podlasie, Polesie, in the Cal/Val AO 3275 campaigns in Poland, during the interval 2006-2009. The test sites have been selected on a basis of their contrasted hydrological conditions. The region Podlasie (Trzebieszow) is essentially drier than the wetland region Polesie (Urszulin). It is worthwhile to note that the soil moisture variations can be represented as a non-stationary random process, and therefore appropriate analysis methods are required. The so-called Empirical Mode Decomposition (EMD) method has been chosen, since it is one of the best methods for the analysis of non-stationary and nonlinear time series. To confirm the results obtained by the EMD we have also used the wavelet methods. Firstly, we have used EMD (analyze step) to decompose the original time series into the so-called Intrinsic Mode Functions (IMFs) and then by grouping and addition similar IMFs (synthesize step) to obtain a few signal components with corresponding temporal scales. Such an adaptive procedure enables to decompose the original time series into diurnal, seasonal and trend components. Revealing of all temporal scales which operates in the original time series is our main objective and this approach may prove to be useful in other studies. Secondly, we have analyzed the soil moisture time series from both sites using the cross-wavelet and wavelet coherency. These methods allow us to study the degree of spatial coherence, which may vary in various intervals of time. We hope the obtained results provide some hints and guidelines for the validation of ESA SMOS data. References: B. Usowicz, J.B. Usowicz, Spatial and temporal variation of selected physical and chemical properties of soil, Institute of Agrophysics, Polish Academy of Sciences, Lublin 2004, ISBN 83-87385-96-4 Rao, A.R., Hsu, E.-C., Hilbert-Huang Transform Analysis of Hydrological and Environmental Time Series, Springer, 2008, ISBN: 978-1-4020-6453-1 Acknowledgements. This work was funded in part by the PECS - Programme for European Cooperating States, No. 98084 "SWEX/R - Soil Water and Energy Exchange/Research".

Bioremediation of petroleum hydrocarbon contaminated soil by Rhodobacter sphaeroides biofertilizer and plants.

PubMed

Jiao, Haihua; Luo, Jinxue; Zhang, Yiming; Xu, Shengjun; Bai, Zhihui; Huang, Zhanbin

2015-09-01

Bio-augmentation is a promising technique for remediation of polluted soils. This study aimed to evaluate the bio-augmentation effect of Rhodobacter sphaeroides biofertilizer (RBF) on the bioremediation of total petroleum hydrocarbons (TPH) contaminated soil. A greenhouse pot experiment was conducted over a period of 120 days, three methods for enhancing bio-augmentation were tested on TPH contaminated soils, including single addition RBF, planting, and combining of RBF and three crop species, such as wheat (W), cabbage (C) and spinach (S), respectively. The results demonstrated that the best removal of TPH from contaminated soil in the RBF bio-augmentation rhizosphere soils was found to be 46.2%, 65.4%, 67.5% for W+RBF, C+RBF, S+RBF rhizosphere soils respectively. RBF supply impacted on the microbial community diversity (phospholipid fatty acids, PLFA) and the activity of soil enzymes, such as dehydrogenase (DH), alkaline phosphatase (AP) and urease (UR). There were significant difference among the soil only containing crude oil (CK), W, C and S rhizosphere soils and RBF bio-augmentation soils. Moreover, the changes were significantly distinct depended on crops species. It was concluded that the RBF is a valuable material for improving effect of remediation of TPH polluted soils.

Measurements, interpretation and climate change effects evaluation for pyroclastic bare soil evaporation

NASA Astrophysics Data System (ADS)

Rianna, G.; Pagano, L.; Mercogliano, P.; Montesarchio, M.

2012-12-01

A physical model has been designed to achieve the following goals: to mark out the main features of the soil-atmosphere interaction; to quantify the water and energy fluxes through the soil surface during several years; to monitor the trends of the main variables regulating the hydraulic and thermal conditions. It is constituted by a soil volume (about 1mc) exposed to weather forcing; it is instrumented at four depths by sensors for measuring suction, water content and temperature. Therefore, a station allows knowing the meteo variables (rainfall, wind velocity and direction, air temperature, air pressure and relative humidity) and the two directly measurable components of the energy balance at the soil surface (net radiation and soil heat flux). Under the soil specimen, three shear beam load cells measure the soil weight and, hence, because the soil particles weight can be assumed as constant, the sample water storage. As first attempt, the soil surface is kept bare to avoid the complications led by overlapping processes induced by vegetation (interception, transpiration). Since May 2010, the soil involved in testing is pyroclastic material (silty sand) representative of air fall deposits covering a large part of Campania (South Italy) and erupted in the last 10,000 years by different volcanic centres (Phlegrean fields, Vesuvius). Because of their genesis, these soils show peculiar features: high porosity, low weight of soil unit volume, high water retention capacity; they cause an unusual hydraulic behaviour, halfway between coarse and fine soils in terms of saturated hydraulic permeability and mean slope of soil-water characteristic curve. In turn, these elements induce, among other things, that the currently adopted predictive approaches to estimate, for example, infiltration and evaporation processes are not directly suitable for these soils as the available parameters, even for grain sizes comparable to those of pyroclastic soils, fail to reproduce the observed trends. The measurements of water weight changes obtained during the dry days of the monitoring time span (2010-2012) furnish an adequately accurate estimate of daily evaporation values and so they can be used to calibrate the parameters of an approach for estimating evaporation method; in this work, the selected model is FAO-56 Dual Crop Coefficient Method for the case of bare soil (Allen et al., 2005) Firstly,the performance of method adopting the set of parameters recommended for soils with the same grain size is tested ; checking poor capability of this set parameters to reproduce the observed values, is retrieved the set for which is obtained best fitting between monitored and estimated values. The dataset covering the monitoring period and the approach so developed can be then used for a preliminary estimate of the effects of incoming climatic changes on evaporation processes in a specific Mediterranean context. Measured air temperatures and precipitation values are modified according their predicted climate anomalies for examined area (Giorgi and Lionello, 2008) in the XXI century; the effect of these variations on potential and actual evaporation through FAO approach are then investigated.

Study on of Seepage Flow Velocity in Sand Layer Profile as Affected by Water Depth and Slope Gradience

NASA Astrophysics Data System (ADS)

Han, Z.; Chen, X.

2017-12-01

BACKGROUND: The subsurface water flow velocity is of great significance in understanding the hydrodynamic characteristics of soil seepage and the influence of interaction between seepage flow and surface runoff on the soil erosion and sediment transport process. OBJECTIVE: To propose a visualized method and equipment for determining the seepage flow velocity and measuring the actual flow velocity and Darcy velocity as well as the relationship between them.METHOD: A transparent organic glass tank is used as the test soil tank, the white river sand is used as the seepage test material and the fluorescent dye is used as the indicator for tracing water flow, so as to determine the thickness and velocity of water flow in a visualized way. Water is supplied at the same flow rate (0.84 L h-1) to the three parts with an interval of 1m at the bottom of the soil tank and the pore water velocity and the thickness of each water layer are determined under four gradient conditions. The Darcy velocity of each layer is calculated according to the water supply flow and the discharge section area. The effective discharge flow pore is estimated according to the moisture content and porosity and then the relationship between Darcy velocity and the measured velocity is calculated based on the water supply flow and the water layer thickness, and finally the correctness of the calculation results is verified. RESULTS: According to the velocity calculation results, Darcy velocity increases significantly with the increase of gradient; in the sand layer profile, the flow velocity of pore water at different depths increases with the increase of gradient; under the condition of the same gradient, the lower sand layer has the maximum flow velocity of pore water. The air-filled porosity of sand layer determines the proportional relationship between Darcy velocity and pore flow velocity. CONCLUSIONS: The actual flow velocity and Darcy velocity can be measured by a visualized method and the relationship between Darcy velocity and pore velocity can be expressed well by the air-filled porosity of sand layer. The flow velocity measurement and test method adopted in the research is effective and feasible. IMPLICATIONS: The visualized flow velocity measurement method can be applied to simulate and measure the characteristics of subsurface water flow in the soil.

Use of Magnetic Parameters to Asses Soil Erosion Rates on Agricultural Site

NASA Astrophysics Data System (ADS)

Petrovsky, E.; Kapicka, A.; Dlouha, S.; Jaksik, O.; Grison, H.; Kodesova, R.

2014-12-01

A detailed field study on a small test site of agricultural land situated in loess region in Southern Moravia (Czech Republic) and laboratory analyses were carried out in order to test the applicability of magnetic methods in assessing soil erosion. Haplic Chernozem, the original dominant soil unit in the area, is nowadays progressively transformed into different soil units along with intense soil erosion. As a result, an extremely diversified soil cover structure has developed due to the erosion. The site was characterized by a flat upper part while the middle part, formed by a substantive side valley, is steeper. We carried out field measurements of magnetic susceptibility on a regular grid, resulting in 101 data points. The bulk soil material for laboratory investigation was gathered from all the grid points. Values of the magnetic susceptibility are spatially distributed depending on the terrain. Higher values were measured in the flat upper part (where the original top horizon remained). The lowest values of were obtained on the steep valley sides. Here the original topsoil was eroded and mixed by tillage with the soil substrate (loess). A soil profile unaffected by erosion was investigated in detail. The vertical distribution of magnetic susceptibility along this "virgin" profile was measured in laboratory on the samples collected with 2-cm spacing. The undisturbed profile shows several soil horizons. Horizons Ac and A show a slight increase in magnetic susceptibility up to a depth of about 70 cm. Horizon A/Ck is characterized by a decrease in susceptibility, and the underlying C horizon (h > 103 cm) has a very low value of magnetic susceptibility. The differences between the values of susceptibility in the undisturbed soil profile and the magnetic signal after uniform mixing the soil material as a result of tillage and erosion are fundamental for the estimation of soil loss in the studied test field. Using the uneroded profile from the studied locality as a basis for examining the changes in cultivated soils, tillage homogenization model can be applied to predict changes in the surface soil magnetism with progressive soil erosion. The model is very well applicable at the studied site. Acknowledgement: This study was supported by NAZV Agency of the Ministry of Agriculture of the Czech Republic through grant No QJ1230319.

[PREDICTING OF RISK OF SOIL CONTAMINATION BY DIFFERENT CLASSES OF FUNGICIDES IN SOIL AND CLIMATIC CONDITIONS OF UKRAINE].

PubMed

Korshun, M; Dema, O; Kucherenko, O; Ruda, T; Korshun, O; Gorbachevskyi, R; Pelio, I; Antonenko, A

2016-07-01

Application of pesticides in modern agriculture is a powerful permanent risk factor for public health and the natural environment. The aim of the study was a comparative hygienic assessment of soil pollution hazards by the most widely used herbicides of different chemical classes (sulfonylureas, imidazolinones, pyrimidinyl (thio) benzoates, semicarbazones). Hygienic field experiment for studying of the dynamics of residual amounts of the test substances in the soil under different climatic zones of Ukraine was conducted. Half life periods (DT50) or herbicides in soil were calculated using the method of mathematical modeling. Ecotoxicological risk of herbicides on ecosystems and ecological communities was determined. It was established that bispyribac-sodium (pyrimidinyl (thio) benzoates) and imidazolinones are persist the longest time in soil and most rapidly degradable is diflufenzopyr (semicarbazone); ecotoxicological risk of the studied herbicides for terrestrial biocenoses of Ukraine by 4-6 orders of magnitude lower than dihlordifeniltrihlormetilmetan (DDT).

Micaceous Soil Strength And Permeability Improvement Induced By Microbacteria From Vegetable Waste

NASA Astrophysics Data System (ADS)

Omar, R. C.; Roslan, R.; Baharuddin, I. N. Z.; Hanafiah, M. I. M.

2016-11-01

Green technology method using vegetable waste are introduced in this paper for improvement of phyllite residual soil from UNITEN, Campus. Residual soil from phyllite are known as micaceous soils and it give problem in managing the stability of the slope especially in wet and extensively dry seasons. Micaceous soil are collected using tube sampler technique and mixed with liquid contain microorganism from fermented vegetable waste name as vege-grout to form remolded sample. The remolded sample are classify as 15.0%, 17.5%, 20.00% and 22.5% based on different incremental percentages of vege-grout. The curing time for the sample are 7, 14, 21, 28, and 35 days before the tests were conducted. Observation of the effect of treatment shows 20.0% of liquid contain Bacillus pasteurii and Bacillus Subtilis with 21 days curing time is the optimum value in strengthening the soil and improve the permeability.

Understanding Dynamic Soil Water Repellency and its Hydrological Implications

NASA Astrophysics Data System (ADS)

Beatty, S. M.; Smith, J. E.

2009-05-01

The adverse effects of water repellent soils on vadose zone hydrology are being increasingly identified worldwide in both rural and urban landscapes. Among the affected landscapes are agricultural fields, forests, effluent application sites, golf greens, wetlands, and wildfire sites. In spite of cross-discipline research efforts put forth in recent years, understanding of fundamental parameters controlling soil water behaviour in these systems is lacking. This is due, in part, to inherent complexities of water repellent soil systems and logistical shortcomings of methods commonly used by researchers in-situ and in the lab. As a result, modeling flow in these systems has further proven to be a difficult task. The objectives of our study were 1) to systematically measure and quantify water infiltration and distribution in dynamic water repellent systems and 2) to identify fundamental hydraulic behaviours that lead to the expression of changes in soil water repellency. To achieve this, we combined techniques to elucidate soil- water interactions at a post-wildfire site. Field tests and subsequent lab work reveal essential hydrological information on fire-affected water repellent soils at variable scales and under different burn conditions. Through the use of traditional and newer techniques, our work shows unique and previously unreported behaviour of soil water in these systems. We also address limitations of current field methods used to study repellency and associated infiltration behaviours.

Role of air on local water retention behavior in the shallow heterogeneous vadose zone

NASA Astrophysics Data System (ADS)

Sakaki, T.; Limsuwat, A.; Illangasekare, T. H.

2009-12-01

In the presence of a subsurface source, air flowing through the unsaturated soil can transport toxic vapor into subsurface structures due to pressure gradients created by, e.g., a pressure drop within the building. Development of dynamic air pathways in the subsurface are largely controlled by the geological heterogeneity and the spatial and temporal distribution of soil moisture. To better understand how these air pathways are developed, it is crucial to know how water is retained in heterogeneous medium at spatial resolutions that are finer than those adopted in typical hydrologic and soil physics applications. Although methods for soil water pressure measurement can be readily found in literature, a technique for measuring “air pressure” in wet soil is not well-established or documented. Hydrophobic porous ceramic cups have been used to measure non-wetting NAPL phase pressure in two-phase systems. However, our preliminary tests using the hydrophobic ceramic cups installed in highly wet soil showed that under conditions of fast drainage of the wetting fluid that is replaced by air, it typically took some time before the cups responded to register the air pressure. Therefore, an attempt was made to develop a more robust method where the time lag is minimized. The tested materials were; 1) ceramic porous cups, 2) sintered stainless steel cups, 3) porous glass discs, and 4) non-woven PTFE fabric. The ceramic cups, sintered stainless steel cups and sintered porous glass discs required hydrophobic treatment, whereas the non-woven PTFE fabric is hydrophobic by itself. To treat the ceramic porous cups, the method proposed by Parker and Lenhard [1988] was adopted. The sintered porous stainless steel cups and porous glass discs were treated by a commercially available water repellant compound. For those four materials, contact angle, water entry pressure, and time lag to respond to an imposed pressure were measured. The best performing material was then tested in a simple heterogeneous column. The column was packed using two sands to form three layers where the coarser sand was sandwitched by two layers of a finer sand. In each layer, soil moisture, water pressure and air pressure were monitored. The soil was initially saturated and suction at the bottom was gradually increased to induce wetting fluid drainage, and followed by a wetting cycle. In the drainage cycle, the coarse middle layer did not drain until air front reached the bottom of the top fine layer. Once the air front reached the fine-coarse interface, air was quickly pulled into the coarse layer. The results showed that the newly developed hydrophobic material showed very small time lag and captured the abrupt air pressure change in the wet soil. In the wetting cycle, we observed positive air pressure which indicated entrapment of air and its compression as wetting proceeded. This behavior cannot be evaluated properly without the rapid measurement of air pressure. The method is currently being applied in a large 2D vertical aquifer with a structured heterogeneity to investigate how air pathways are formed under various flux/temperature conditions at the soil surface.

Termiticides - the Gulfport report

Treesearch

Bradford M. Kard

1999-01-01

Termiticide treatments to soil are the most widely used and successful method to protect wooden structures from attack by subterranean termites and potentially new termiticides continue to be placed in Forest Service field tests each year. This article presents the latest findings taken from USDA Forest Service field tests in Arizona, Florida, Mississippi, and South...

SUPERFUND TREATABILITY CLEARINGHOUSE: INCINERATION TEST OF EXPLOSIVES CONTAMINATED SOILS AT SAVANNA ARMY DEPOT ACTIVITY, SAVANNA, ILLINOIS

EPA Science Inventory

The primary objective of these tests was to demonstrate the effectiveness of incineration as a decontamination method for explosives contaminated sails. A pilot-scale rotary kiln incinerator, manufactured by ThermAll, Inc., was used to treat both sandy and clayey...

EVALUATION OF ALTERNATIVE REFERENCE TOXICANTS FOR USE IN THE EARTHWORM TOXICITY TEST

EPA Science Inventory

The use of the 14-d earthworm toxicity test to aid in the evaluation of the ecological impact of contaminated soils is becoming increasingly widespread. However,the method is in need of further standardization. As part of this continuing process, the choice of reference toxicants...

Inorganic species of arsenic in soil solution determined by microcartridges and ferrihydrite-based diffusive gradient in thin films (DGT).

PubMed

Moreno-Jiménez, Eduardo; Six, Laetitia; Williams, Paul N; Smolders, Erik

2013-01-30

The bioavailability of soil arsenic (As) is determined by its speciation in soil solution, i.e., arsenite [As(III)] or arsenate [As(V)]. Soil bioavailability studies require suitable methods to cope with small volumes of soil solution that can be speciated directly after sampling, and thereby minimise any As speciation change during sample collection. In this study, we tested a self-made microcartridge to separate both As species and compared it to a commercially available cartridge. In addition, the diffusive gradient in thin films technique (DGT), in combination with the microcartridges, was applied to synthetic solutions and to a soil spiked with As. This combination was used to improve the assessment of available inorganic As species with ferrihydrite(FH)-DGT, in order to validate the technique for environmental analysis, mainly in soils. The self-made microcartridge was effective in separating As(III) from As(V) in solution with detection by inductively coupled plasma optical emission spectrometry (ICP-OES) in volumes of only 3 ml. The DGT study also showed that the FH-based binding gels are effective for As(III) and As(V) assessment, in solutions with As and P concentrations and ionic strength commonly found in soils. The FH-DGT was tested on flooded and unflooded As spiked soils and recoveries of As(III) and As(V) were 85-104% of the total dissolved As. This study shows that the DGT with FH-based binding gel is robust for assessing inorganic species of As in soils. Copyright © 2012 Elsevier B.V. All rights reserved.

Heavy metal pollution in farmland irrigated with river water near a steel plant—magnetic and geochemical signature

NASA Astrophysics Data System (ADS)

Zhang, Chunxia; Appel, Erwin; Qiao, Qingqing

2013-03-01

The presence of heavy metals (HMs) in the environment is a major threat for humans. Magnetic proxies provide a rapid method for assessing the degree of HM pollution in environment. We have studied farmland soil irrigated with polluted river water in the vicinity of a steel plant in Loudi city (Hunan Province, China) to test the efficiency of magnetic methods for detecting the degree of HM pollution. Both magnetic and non-magnetic (microscopic, chemical and statistical) methods were used to characterize these farmland soils. Enhanced magnetic concentration values were found in the upper arable soil horizon (0-20 cm), which is related to the presence of spherical ˜10 to 30 μm sized magnetite particles. The spatial distribution of magnetic concentration and HM contents in the farmland soils matches with the spatial pattern of these parameters in river sediments. These findings provide evidence that HM pollution of the farmland soil is mainly caused by irrigation with wastewater. HMs Zn, Pb, Cu, Cd, Co, Ni, V are well correlate with magnetic susceptibility (χ). The pollution load index (PLI) of all nine anthropogenic HMs (including also Cr and Mo) and log10(χ) are significantly correlated. Using the resulting linear PLI-log10(χ) function, values of χ can serve as a convenient tool for semi-quantifying the degree of HM pollution in the uppermost ˜20 cm of the studied farmland soils. These findings suggest that magnetic methods can generally serve as a convenient tool for detecting and mapping HM pollution in farmland soil irrigated with wastewater from sites nearby heavy industrial activities.

Mars Pathfinder Wheel Abrasion Experiment Ground Test

NASA Technical Reports Server (NTRS)

Keith, Theo G., Jr.; Siebert, Mark W.

1998-01-01

The National Aeronautics and Space Administration (NASA) sent a mission to the martian surface, called Mars Pathfinder. The mission payload consisted of a lander and a rover. The primary purpose of the mission was demonstrating a novel entry, descent, and landing method that included a heat shield, a parachute, rockets, and a cocoon of giant air bags. Once on the surface, the spacecraft returned temperature measurements near the Martian surface, atmosphere pressure, wind speed measurements, and images from the lander and rover. The rover obtained 16 elemental measurements of rocks and soils, performed soil-mechanics, atmospheric sedimentation measurements, and soil abrasiveness measurements.

Remote sensing as a source of land cover information utilized in the universal soil loss equation

NASA Technical Reports Server (NTRS)

Morris-Jones, D. R.; Morgan, K. M.; Kiefer, R. W.; Scarpace, F. L.

1979-01-01

In this study, methods for gathering the land use/land cover information required by the USLE were investigated with medium altitude, multi-date color and color infrared 70-mm positive transparencies using human and computer-based interpretation techniques. Successful results, which compare favorably with traditional field study methods, were obtained within the test site watershed with airphoto data sources and human airphoto interpretation techniques. Computer-based interpretation techniques were not capable of identifying soil conservation practices but were successful to varying degrees in gathering other types of desired land use/land cover information.

Is a Water Content of 60% Maximum Water Holding Capacity Suitable for Folsomia candida Reproduction Tests? A Study with Silver Nanoparticles and AgNO3

PubMed Central

McKee, Moira S.; Megía Guerrero, Amelia; Filser, Juliane

2018-01-01

Silver nanoparticles (AgNP) are increasingly emitted to the environment due to a rise in application in various products; therefore, assessment of their potential risks for biota is important. In this study the effects of AgNP at environmentally relevant concentrations (0.6–375 µg kg−1 soil) on the soil invertebrate Folsomia candida in OECD (Organisation for Economic Co-operation and Development) soil was examined at different soil water contents. Animals were retrieved by heat extraction, which had an efficiency of about 90% compared with the floatation method. The tested water content range is set by OECD Guideline 232 (40–60% of the maximum water holding capacity, WHC), and we detected significant differences in toxicity due to these. With AgNO3, used as an ionic control, the number of juveniles significantly decreased only at 40% WHC, which might be due to dilution of the toxicant at higher soil water content. In turn, at 60% WHC, the reproduction of F. candida significantly increased in the presence of AgNP compared with in the control. However, at this water content, the required number of juveniles in the control treatment was not reached in three independent tests. The fact that the OECD validity criterion is not met indicates that the soil conditions are not suitable for reproduction at 60% WHC. PMID:29614765

Leaching standards for mineral recycling materials--a harmonized regulatory concept for the upcoming German Recycling Decree.

PubMed

Susset, Bernd; Grathwohl, Peter

2011-02-01

In this contribution we give a first general overview of results of recent studies in Germany which focused on contaminant leaching from various materials and reactive solute transport in the unsaturated soil zone to identify the key factors for groundwater risk assessment. Based on these results we developed new and improved existing methods for groundwater risk assessment which are used to derive a new regulatory concept for the upcoming "Decree for the Requirements of the Use of Alternative Mineral Building Materials in Technical Constructions and for the Amendment of the Federal Soil Protection and Contaminated Sites Ordinance" of the German Federal Ministry of Environment. The new concept aims at a holistic and scientifically sound assessment of the use of mineral recycling materials (e.g., mineral waste, excavated soils, slag and ashes, recycling products, etc.) in technical constructions (e.g., road dams) and permanent applications (e.g., backfilling and landscaping) which is based on a mechanistic understanding of leaching and transport processes. Fundamental for risk assessment are leaching standards for the mineral recycling materials. For each application of mineral recycling materials specific maximum concentrations of a substance in the seepage water at the bottom of an application were calculated. Technical boundary conditions and policy conventions derived from the "German precautionary groundwater and soil protection policy" were accounted to prevent adverse environmental effects on the media soil and groundwater. This includes the concentration decline of highly soluble substances (e.g., chloride and sulphate), retardation or attenuation of solutes, accumulation of contaminants in sub-soils and the hydraulic properties of recycling materials used for specific applications. To decide whether the use of a mineral recycling material is possible in a specific application, the leaching qualities were evaluated based on column percolation tests with various samples and compared with application-specific maximum concentrations. In the upcoming federal decree this simplified concept is realized using detailed tables which classify the leaching quality of mineral recycling materials and demonstrate potential application. A quality assurance system will be mandatory which defines specific testing programs (material properties and limit concentrations to be tested, number and schedule of testing) for the different mineral recycling materials using standardized methods (column percolation test). Copyright © 2010 Elsevier Ltd. All rights reserved.

Effect of the method of estimation of soil saturated hydraulic conductivity with regards to the design of stormwater infiltration trenches

NASA Astrophysics Data System (ADS)

Paiva coutinho, Artur; Predelus, Dieuseul; Lassabatere, Laurent; Ben Slimene, Erij; Celso Dantas Antonino, Antonio; Winiarski, Thierry; Joaquim da Silva Pereira Cabral, Jaime; Angulo-Jaramillo, Rafael

2014-05-01

Best management practices are based on the infiltration of stormwater (e.g. infiltration into basins or trenches) to reduce the risk of flooding of urban areas. Proper estimations of saturated hydraulic conductivity of the vadose zone are required to avoid inappropriate design of infiltration devices. This article aims at assessing (i) the method-dependency of the estimation of soils saturated hydraulic conductivity and (ii) the consequences of such dependency on the design of infiltration trenches. This is illustrated for the specific case of an infiltration trench to be constructed to receive stormwater from a specific parking surface, 250 m2 in area, in Recife (Brazil). Water infiltration experiments were conducted according to the Beerkan Method, i.e. application of a zero water pressure head through a disc source (D=15 cm) and measures of the amount of infiltrated water with time. Saturated hydraulic conductivity estimates are derived from the analysis of these infiltration tests using several different conceptual approaches: one-dimensional models of Horton(1933) and Philip(1957), three-dimensional methods recently developed (Lassabatere et al., 2006, Wu et al., 1999, and Bagarello et al., 2013) and direct 3-dimensional numerical inversion. The estimations for saturated hydraulic conductivity ranged between 65.5 mm/h and 94 mm/h for one-dimensional methods, whereas using three-dimensional methods saturated hydraulic conductivity ranged between 15.6 mm/h and 50 mm/h. These results shows the need for accounting for 3D geometry, and more generally, the physics of water infiltration in soils, if a proper characterization of soil saturated hydraulic conductivity is targeted. In a second step, each estimate of the saturated hydraulic conductivity was used to calculate the stormwater to be stored in the studied trench for several rainfall events of recurrence intervals of 2 to 25 years. The calculation of these volumes showed a great sensitivity with regards to the estimated values of saturated hydraulic conductivity. The designed volumes of the trench vary from 8.3 m3 to 15.9 m3 for one-dimensional methods and 11.9 m3 to 24.5 m3 for three-dimensional methods, respectively. The results show that any miss-estimation of the saturated hydraulic conductivity of soils may drastically impact the design of infiltration devices and the related extra-costs. Bagarello, B.; Castellini, M.; Di Prima,S.;Giordano ,G.; Iovino, M. (2013). Testing a simplified approach to determine field saturated soil hydraulic conductivity. Procedia Environmental Sciences 19 ( 2013 ) 599 - 608 Horton, R. (1933). The role of infiltration in the hydrologic cycle. American Geophysical Union Transactions 14, 446-460. Lassabatère, L.; Angulo-Jaramillo, R.; Soria, J.M.; Cuenca, R.; Braud, I.; Haverkamp, R.(2006). Beerkan estimation of soil transfer parameters through infiltration experiments - BEST. Soil Science Society of American Journal, Madison, v.70, p.521-532, 2006. Philip, J.R. (1957). The theory of Infiltration: 5. The Influence of the Initial Moisture Content. Soil Science, v.4, n.84, p.329-339, 1957. Wu, L.; Pan, L.; Mitchell, J.; Sanden, B. (1999). Measuring satured hydraulic conductivity using a generalized solution for single-ringle infiltrometers. Soil Sci.Soc.Am.J.63, 788-792

The geostatistic-based spatial distribution variations of soil salts under long-term wastewater irrigation.

PubMed

Wu, Wenyong; Yin, Shiyang; Liu, Honglu; Niu, Yong; Bao, Zhe

2014-10-01

The purpose of this study was to determine and evaluate the spatial changes in soil salinity by using geostatistical methods. The study focused on the suburb area of Beijing, where urban development led to water shortage and accelerated wastewater reuse to farm irrigation for more than 30 years. The data were then processed by GIS using three different interpolation techniques of ordinary kriging (OK), disjunctive kriging (DK), and universal kriging (UK). The normality test and overall trend analysis were applied for each interpolation technique to select the best fitted model for soil parameters. Results showed that OK was suitable for soil sodium adsorption ratio (SAR) and Na(+) interpolation; UK was suitable for soil Cl(-) and pH; DK was suitable for soil Ca(2+). The nugget-to-sill ratio was applied to evaluate the effects of structural and stochastic factors. The maps showed that the areas of non-saline soil and slight salinity soil accounted for 6.39 and 93.61%, respectively. The spatial distribution and accumulation of soil salt were significantly affected by the irrigation probabilities and drainage situation under long-term wastewater irrigation.