Soil-plant transfer models for metals to improve soil screening value guidelines valid for São Paulo, Brazil.

PubMed

Dos Santos-Araujo, Sabrina N; Swartjes, Frank A; Versluijs, Kees W; Moreno, Fabio Netto; Alleoni, Luís R F

2017-11-07

In Brazil, there is a lack of combined soil-plant data attempting to explain the influence of specific climate, soil conditions, and crop management on heavy metal uptake and accumulation by plants. As a consequence, soil-plant relationships to be used in risk assessments or for derivation of soil screening values are not available. Our objective in this study was to develop empirical soil-plant models for Cd, Cu, Pb, Ni, and Zn, in order to derive appropriate soil screening values representative of humid tropical regions such as the state of São Paulo (SP), Brazil. Soil and plant samples from 25 vegetable species in the production areas of SP were collected. The concentrations of metals found in these soil samples were relatively low. Therefore, data from temperate regions were included in our study. The soil-plant relations derived had a good performance for SP conditions for 8 out of 10 combinations of metal and vegetable species. The bioconcentration factor (BCF) values for Cd, Cu, Ni, Pb, and Zn in lettuce and for Cd, Cu, Pb, and Zn in carrot were determined under three exposure scenarios at pH 5 and 6. The application of soil-plant models and the BCFs proposed in this study can be an important tool to derive national soil quality criteria. However, this methodological approach includes data assessed under different climatic conditions and soil types and need to be carefully considered.

Dalton Highway : characterization of foundation soils

DOT National Transportation Integrated Search

1984-09-01

In this report we represent the results of our geotechnical characterization of natural foundation soils along the Dalton Highway from the Livengood to Prudhoe Bay. In addition, it analyzes this data by statistical methods and caracterizes foundation...

A comparison between probability and information measures of uncertainty in a simulated soil map and the economic value of imperfect soil information.

NASA Astrophysics Data System (ADS)

Lark, R. Murray

2014-05-01

Conventionally the uncertainty of a conventional soil map has been expressed in terms of the mean purity of its map units: the probability that the soil profile class examined at a site would be found to correspond to the eponymous class of the simple map unit that is delineated there (Burrough et al, 1971). This measure of uncertainty has an intuitive meaning and is used for quality control in soil survey contracts (Western, 1978). However, it may be of limited value to the manager or policy maker who wants to decide whether the map provides a basis for decision making, and whether the cost of producing a better map would be justified. In this study I extend a published analysis of the economic implications of uncertainty in a soil map (Giasson et al., 2000). A decision analysis was developed to assess the economic value of imperfect soil map information for agricultural land use planning. Random error matrices for the soil map units were then generated, subject to constraints which ensure consistency with fixed frequencies of the different soil classes. For each error matrix the mean map unit purity was computed, and the value of the implied imperfect soil information was computed by the decision analysis. An alternative measure of the uncertainty in a soil map was considered. This is the mean soil map information which is the difference between the information content of a soil observation, at a random location in the region, and the information content of a soil observation given that the map unit is known. I examined the relationship between the value of imperfect soil information and the purity and information measures of map uncertainty. In both cases there was considerable variation in the economic value of possible maps with fixed values of the uncertainty measure. However, the correlation was somewhat stronger with the information measure, and there was a clear upper bound on the value of an imperfect soil map when the mean information takes some

Geophysical characterization of soil moisture spatial patterns in a tillage experiment

NASA Astrophysics Data System (ADS)

Martinez, G.; Vanderlinden, K.; Giráldez, J. V.; Muriel, J. L.

2009-04-01

Knowledge on the spatial soil moisture pattern can improve the characterisation of the hydrological response of either field-plots or small watersheds. Near-surface geophysical methods, such as electromagnetic induction (EMI), provide a means to map such patterns using non-invasive and non-destructive measurements of the soil apparent electrical conductivity (ECa. In this study ECa was measured using an EMI sensor and used to characterize spatially the hydrologic response of a cropped field to an intense shower. The study site is part of a long-term tillage experiment in Southern Spain in which Conventional Tillage (CT), Direct Drilling (DD) and Minimum Tillage (MT) are being evaluated since 1982. Soil ECa was measured before and after a rain event of 115 mm, near the soil surface and at deeper depth (ECas and ECad, respectively) using the EM38-DD EMI sensor. Simultaneously, elevation data were collected at each sampling point to generate a Digital Elevation Model (DEM). Soil moisture during the first survey was close to permanent wilting point and near field capacity during the second survey. For the first survey, both ECas and ECad, were higher in the CT and MT than in the DD plots. After the rain event, rill erosion appeared only in CT and MT plots were soil was uncovered, matching the drainage lines obtained from the DEM. Apparent electrical conductivity increased all over the field plot with higher increments in the DD plots. These plots showed the highest ECas and ECad values, in contrast to the spatial pattern found during the first sampling. Difference maps obtained from the two ECas and ECad samplings showed a clear difference between DD plots and CT and MT plots due to their distinct hydrologic response. Water infiltration was higher in the soil of the DD plots than in the MT and CT plots, as reflected by their ECad increment. Higher ECa increments were observed in the depressions of the terrain, where water and sediments accumulated. On the contrary, the

Using lagged dependence to identify (de)coupled surface and subsurface soil moisture values

NASA Astrophysics Data System (ADS)

Carranza, Coleen D. U.; van der Ploeg, Martine J.; Torfs, Paul J. J. F.

2018-04-01

Recent advances in radar remote sensing popularized the mapping of surface soil moisture at different spatial scales. Surface soil moisture measurements are used in combination with hydrological models to determine subsurface soil moisture values. However, variability of soil moisture across the soil column is important for estimating depth-integrated values, as decoupling between surface and subsurface can occur. In this study, we employ new methods to investigate the occurrence of (de)coupling between surface and subsurface soil moisture. Using time series datasets, lagged dependence was incorporated in assessing (de)coupling with the idea that surface soil moisture conditions will be reflected at the subsurface after a certain delay. The main approach involves the application of a distributed-lag nonlinear model (DLNM) to simultaneously represent both the functional relation and the lag structure in the time series. The results of an exploratory analysis using residuals from a fitted loess function serve as a posteriori information to determine (de)coupled values. Both methods allow for a range of (de)coupled soil moisture values to be quantified. Results provide new insights into the decoupled range as its occurrence among the sites investigated is not limited to dry conditions.

Successive DNA extractions improve characterization of soil microbial communities

PubMed Central

de Hollander, Mattias; Smidt, Hauke; van Veen, Johannes A.

2017-01-01

Currently, characterization of soil microbial communities relies heavily on the use of molecular approaches. Independently of the approach used, soil DNA extraction is a crucial step, and success of downstream procedures will depend on how well DNA extraction was performed. Often, studies describing and comparing soil microbial communities are based on a single DNA extraction, which may not lead to a representative recovery of DNA from all organisms present in the soil. The use of successive DNA extractions might improve soil microbial characterization, but the benefit of this approach has only been limitedly studied. To determine whether successive DNA extractions of the same soil sample would lead to different observations in terms of microbial abundance and community composition, we performed three successive extractions, with two widely used commercial kits, on a range of clay and sandy soils. Successive extractions increased DNA yield considerably (1–374%), as well as total bacterial and fungal abundances in most of the soil samples. Analysis of the 16S and 18S ribosomal RNA genes using 454-pyrosequencing, revealed that microbial community composition (taxonomic groups) observed in the successive DNA extractions were similar. However, successive DNA extractions did reveal several additional microbial groups. For some soil samples, shifts in microbial community composition were observed, mainly due to shifts in relative abundance of a number of microbial groups. Our results highlight that performing successive DNA extractions optimize DNA yield, and can lead to a better picture of overall community composition. PMID:28168105

Sampling Soil for Characterization and Site Description

NASA Technical Reports Server (NTRS)

Levine, Elissa

1999-01-01

The sampling scheme for soil characterization within the GLOBE program is uniquely different from the sampling methods of the other protocols. The strategy is based on an understanding of the 5 soil forming factors (parent material, climate, biota, topography, and time) at each study site, and how each of these interact to produce a soil profile with unique characteristics and unique input and control into the atmospheric, biological, and hydrological systems. Soil profile characteristics, as opposed to soil moisture and temperature, vegetative growth, and atmospheric and hydrologic conditions, change very slowly, depending on the parameter being measured, ranging from seasonally to many thousands of years. Thus, soil information, including profile description and lab analysis, is collected only one time for each profile at a site. These data serve two purposes: 1) to supplement existing spatial information about soil profile characteristics across the landscape at local, regional, and global scales, and 2) to provide specific information within a given area about the basic substrate to which elements within the other protocols are linked. Because of the intimate link between soil properties and these other environmental elements, the static soil properties at a given site are needed to accurately interpret and understand the continually changing dynamics of soil moisture and temperature, vegetation growth and phenology, atmospheric conditions, and chemistry and turbidity in surface waters. Both the spatial and specific soil information can be used for modeling purposes to assess and make predictions about global change.

Characterization of soil spatial variability for site-specific management using soil electrical conductivity and other remotely sensed data

NASA Astrophysics Data System (ADS)

Bang, Jisu

Field-scale characterization of soil spatial variability using remote sensing technology has potential for achieving the successful implementation of site-specific management (SSM). The objectives of this study were to: (i) examine the spatial relationships between apparent soil electrical conductivity (EC a) and soil chemical and physical properties to determine if EC a could be useful to characterize soil properties related to crop productivity in the Coastal Plain and Piedmont of North Carolina; (ii) evaluate the effects of in-situ soil moisture variation on ECa mapping as a basis for characterization of soil spatial variability and as a data layer in cluster analysis as a means of delineating sampling zones; (iii) evaluate clustering approaches using different variable sets for management zone delineation to characterize spatial variability in soil nutrient levels and crop yields. Studies were conducted in two fields in the Piedmont and three fields in the Coastal Plain of North Carolina. Spatial measurements of ECa via electromagnetic induction (EMI) were compared with soil chemical parameters (extractable P, K, and micronutrients; pH, cation exchange capacity [CEC], humic matter or soil organic matter; and physical parameters (percentage sand, silt, and clay; and plant-available water [PAW] content; bulk density; cone index; saturated hydraulic conductivity [Ksat] in one of the coastal plain fields) using correlation analysis across fields. We also collected ECa measurements in one coastal plain field on four days with significantly different naturally occurring soil moisture conditions measured in five increments to 0.75 m using profiling time-domain reflectometry probes to evaluate the temporal variability of ECa associated with changes in in-situ soil moisture content. Nonhierarchical k-means cluster analysis using sensor-based field attributes including vertical ECa, near-infrared (NIR) radiance of bare-soil from an aerial color infrared (CIR) image

A Soil Service Index: a method for quantifying the value, vulnerability, and status of soil resources

NASA Astrophysics Data System (ADS)

Harden, J. W.; Loisel, J.; Hugelius, G.; Sulman, B. N.; Bond-Lamberty, B. P.; Abramoff, R. Z.; Malhotra, A.; Gill, A. L.

2017-12-01

Soils support ecological and human systems by providing a physical and biogeochemical basis for plant growth, ecological functions, water quality, and water storage, and by providing services and functions needed for economic development, human well-being, and conservation of natural resources. Quantitative evaluation of soil services, however, is inconsistent and poorly communicated, in part because we lack a scientific, unified basis for evaluating soils and their potential for serving our needs. We introduce an index of soil service (SSI) in which multiple services are numerically or quantitatively assessed, normalized to a unit-less scale for purposes of intercomparability, and evaluated for a given site or region. Services include organic matter and/or organic carbon storage; plant productivity; CO2 or GHG exchange with the atmosphere; water storage capacity; and nutrient storage and/or availability. The status of SSI can be evaluated by individual services or by a composite index that combines multiple services. The status can be monitored over time; and key services that are more highly valued for a given soil can be weighted accordingly in comparison to other services. As a first step, existing data for each service are captured from a literature and data review in order to establish the full range of values. A site value establishes the ranking relative to the full range. Key services are weighted according to local values. A final index is the sum of the normalized, weighted products. Metrics can be updated and adapted as new data or services are discovered or recognized. Metrics can be used to compare among sites, regions, or time periods.

A Novel Method for Measurement and Characterization of Soil Macroporosity

Treesearch

Christopher Barton; Tasos Karathanasis

2002-01-01

Quantitative macropore characterizations were performed in large zero-tension soil lysimeters of a Maury silt loam (fine, mixed, mesic Typic Paleudalf) and a Loradale silt loam (fine, silty, mixed, mesic Typic Axgiudoll) soil in an effort to assess potential colloid transport. Steel pipe sections (50 cm diameter X 100 cm length) were hydraulically driven into the soil...

A Soil Service Index: Peatland soils as a case study for quantifying the value, vulnerability, and status of soils

NASA Astrophysics Data System (ADS)

Loisel, J.; Harden, J. W.; Hugelius, G.

2017-12-01

What are the most important soil services valued by land stewards and planners? Which soil-data metrics can be used to quantify each soil service? What are the steps required to quantitatively index the baseline value of soil services and their vulnerability under different land-use and climate change scenarios? How do we simulate future soil service pathways (or trajectories) under changing management regimes using process-based ecosystem models? What is the potential cost (economic, social, and other) of soil degradation under these scenarios? How sensitive or resilient are soil services to prescribed management practices, and how does sensitivity vary over space and time? We are bringing together a group of scientists and conservation organizations to answer these questions by launching Soil Banker, an open and flexible tool to quantify soil services that can be used at any scale, and by any stakeholder. Our overarching goals are to develop metrics and indices to quantify peatland soil ecosystem services, monitor change of these services, and guide management. This paper describes our methodology applied to peatlands and presents two case studies (Indonesia and Patagonia) demonstrating how Peatland Soil Banker can be deployed as an accounting tool of peatland stocks, a quantitative measure of peatland health, and as a projection of peatland degradation or enhancement under different land-use cases. Why peatlands? They store about 600 billion tons of carbon that account for ⅓ of the world's soil carbon. Peatlands have dynamic GHG exchanges of CO2, CH4, and NOx with the atmosphere, which plays a role in regulating global climate; studies indicate that peatland degradation releases about 2-3 billion tons of CO2 to the atmosphere annually. These ecosystems also provide local and regional ecosystem services: they constitute important components of the N and P cycles, store about 10% of the world's freshwater and buffer large fluxes of freshwater on an annual basis

CHARACTERIZATION OF CHROMIUM-CONTAMINATED SOILS USING FIELD-PORTABLE X-RAY FLUORESCENCE

EPA Science Inventory

A detailed characterization of the underlying and adjacent soils near a chrome plating shop utilized field-portable X- ray fluorescence (XRF) as a screening tool. XRF permitted real-time acquisition of estimates for total metal content of soils. A trailer-mounted soil coring unit...

Determination of the Characteristic Values and Variation Ratio for Sensitive Soils

NASA Astrophysics Data System (ADS)

Milutinovici, Emilia; Mihailescu, Daniel

2017-12-01

In 2008, Romania adopted Eurocode 7, part II, regarding the geotechnical investigations - called SR EN1997-2/2008. However a previous standard already existed in Romania, by using the mathematical statistics in determination of the calculation values, the requirements of Eurocode can be taken into consideration. The setting of characteristics and calculations values of the geotechnical parameters was finally issued in Romania at the end of 2010 at standard NP122-2010 - “Norm regarding determination of the characteristic and calculation values of the geotechnical parameters”. This standard allows using of data already known from analysed area and setting the calculation values of geotechnical parameters. However, this possibility exist, it is not performed easy in Romania, considering that there isn’t any centralized system of information coming from the geotechnical studies performed for various objectives of private or national interests. Every company performing geotechnical studies tries to organize its own data base, but unfortunately none of them use existing centralized data. When determining the values of calculation, an important role is played by the variation ratio of the characteristic values of a geotechnical parameter. There are recommendations in the mentioned Norm, that could be taken into account, regarding the limits of the variation ratio, but these values are mentioned for Quaternary age soils only, normally consolidated, with a content of organic material < 5%. All of the difficult soils are excluded from the Norm even if they exist and affect the construction foundations on more than a half of the Romania’s surface. A type of difficult soil, extremely widespread on the Romania’s territory, is the contractile soil (with high swelling and contractions, very sensitive to the seasonal moisture variations). This type of material covers and influences the construction foundations in one over third of Romania’s territory. This work is

Use of photoacoustic mid-infrared spectroscopy to characterize soil properties and soil organic matter stability

NASA Astrophysics Data System (ADS)

Peltre, Clement; Bruun, Sander; Du, Changwen; Stoumann Jensen, Lars

2014-05-01

The persistence of soil organic matter (SOM) is recognized as a major ecosystem property due to its key role in earth carbon cycling, soil quality and ecosystem services. SOM stability is typically studied using biological methods such as measuring CO2-C evolution from microbial decomposition of SOM during laboratory incubation or by physical or chemical fractionation methods, allowing the separation of a labile fraction of SOM. However these methods are time consuming and there is still a need for developing reliable techniques to characterize SOM stability, providing both quantitative measurements and qualitative information, in order to improve our understanding of the mechanisms controlling SOM persistence. Several spectroscopic techniques have been used to characterize and predict SOM stability, such as near infrared reflectance spectroscopy (NIRS) and diffuse reflectance mid-infrared spectroscopy (DRIFT). The latter allows a proper identification of spectral regions corresponding to vibrations of specific molecular or functional groups associated with SOM lability. However, reflectance spectroscopy for soil analyses raises some difficulties related to the low reflectance of soils, and to the high influence of particle size. In the last three decades, the progresses in microphone sensitivity dramatically increased the performance of photoacoustic Fourier transform mid-infrared spectroscopy (FTIR-PAS). This technique offers benefits over reflectance spectroscopy techniques, because particle size and the level of sample reflectance have little effect of on the PAS signal, since FTIR-PAS is a direct absorption technique. Despite its high potential for soil analysis, only a limited number of studies have so far applied FTIR-PAS for soil characterization and its potential for determining SOM degradability still needs to be investigated. The objective of this study was to assess the potential of FTIR-PAS for the characterization of SOM decomposability during

The Value Range of Contact Stiffness Factor between Pile and Soil Based on Penalty Function

NASA Astrophysics Data System (ADS)

Chen, Sandy H. L.; Wu, Xinliu

2018-03-01

The value range of contact stiffness factor based on penalty function is studied when we use finite element software ANSYS to analyze contact problems, take single pile and soil of a certain project for example, the normal contact between pile and soil is analyzed with 2D simplified model in horizontal load. The study shows that when adopting linear elastic model to simulate soil, the maximum contact pressure and penetration approach steady value as the contact stiffness factor increases. The reasonable value range of contact stiffness factor reduces as the underlying element thickness decreases, but the rule reverses when refers to the soil stiffness. If choose DP model to simulate soil, the stiffness factor should be magnified 100 times compares to the elastic model regardless of the soil bears small force and still in elastic deformation stage or into the plastic deformation stage. When the soil bears big force and into plastic deformation stage, the value range of stiffness factor relates to the plastic strain range of the soil, and reduces as the horizontal load increases.

CHARACTERIZING SOILS FOR HAZAROUDS WASTE SITE ASSESSMENTS

EPA Science Inventory

The purpose of this paper is to provide guidance to Remedial Project Managers (RPM) and On-Scene Coordinators (OSC) concerning soil characterization data types required for decision-making in the CERCLA RI/FS process related to risk assessment and remedial alternative evaluation ...

The Estimation of Compaction Parameter Values Based on Soil Properties Values Stabilized with Portland Cement

NASA Astrophysics Data System (ADS)

Lubis, A. S.; Muis, Z. A.; Pasaribu, M. I.

2017-03-01

The strength and durability of pavement construction is highly dependent on the properties and subgrade bearing capacity. This then led to the idea of the selection methods to estimate the density of the soil with the proper implementation of the system, fast and economical. This study aims to estimate the compaction parameter value namely the maximum dry unit weight (γd max) and optimum moisture content (wopt) of the soil properties value that stabilized with Portland Cement. Tests conducted in the laboratory of soil mechanics to determine the index properties (fines and liquid limit) and Standard Compaction Test. Soil samples that have Plasticity Index (PI) between 0-15% then mixed with Portland Cement (PC) with variations of 2%, 4%, 6%, 8% and 10%, each 10 samples. The results showed that the maximum dry unit weight (γd max) and wopt has a significant relationship with percent fines, liquid limit and the percentation of cement. Equation for the estimated maximum dry unit weight (γd max) = 1.782 - 0.011*LL + 0,000*F + 0.006*PS with R2 = 0.915 and the estimated optimum moisture content (wopt) = 3.441 + 0.594*LL + 0,025*F + 0,024*PS with R2 = 0.726.

Next steps in the development of ecological soil clean-up values for metals.

PubMed

Wentsel, Randall; Fairbrother, Anne

2014-07-01

This special series in Integrated Environmental Assessment Management presents the results from 6 workgroups that were formed at the workshop on Ecological Soil Levels-Next Steps in the Development of Metal Clean-Up Values (17-21 September 2012, Sundance, Utah). This introductory article presents an overview of the issues assessors face when conducting risk assessments for metals in soils, key US Environmental Protection Agency (USEPA) documents on metals risk assessment, and discusses the importance of leveraging from recent major terrestrial research projects, primarily to address Registration, Evaluation, Authorization and Restriction of Chemical Substances (REACH) requirements in Europe, that have significantly advanced our understanding of the behavior and toxicity of metals in soils. These projects developed large data sets that are useful for the risk assessment of metals in soil environments. The workshop attendees met to work toward developing a process for establishing ecological soil clean-up values (Eco-SCVs). The goal of the workshop was to progress from ecological soil screening values (Eco-SSLs) to final clean-up values by providing regulators with the methods and processes to incorporate bioavailability, normalize toxicity thresholds, address food-web issues, and incorporate background concentrations. The REACH data sets were used by workshop participants as case studies in the development of the ecological standards for soils. The workshop attendees discussed scientific advancements in bioavailability, soil biota and wildlife case studies, soil processes, and food-chain modeling. In addition, one of the workgroups discussed the processes needed to frame the topics to gain regulatory acceptance as a directive or guidance by Canada, the USEPA, or the United States. © 2013 SETAC.

Characterization of soils from an industrial complex contaminated with elemental mercury

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

Miller, Carrie L; Watson, David B; Liang, Liyuan

2013-01-01

Historic use of liquid elemental mercury (Hg(0)l) at the Y-12 National Security Complex in Oak Ridge, TN, USA resulted in large deposits of Hg(0)l in the soils. An evaluation of analytical tools for characterizing the speciation of Hg in the soils at the Y-12 facility was conducted and these tequniques were used to examine the speciation of Hg in two soil cores collect at the site. These include X-ray fluorescence (XRF), soil Hg(0) headspace analysis, and total Hg determination by acid digestion coupled with cold vapor atomic absorption. Hg concentrations determined using XRF, a tool that has been suggestions formore » quick onsite characterization of soils, were lower than concentrations determined by HgT analysis and as a result this technique is not suitable for the evaluation of Hg concentrations in heterogeneous soils containing Hg(0)l. Hg(0)g headspace analysis can be used to examine the presence of Hg(0)l in soils and when coupled with HgT analysis an understanding of the speciation of Hg in soils can be obtained. Two soil cores collected within the Y-12 complex highlight the heterogeneity in the depth and extent of Hg contamination, with Hg concentrations ranging from 0.05 to 8400 mg/kg. At one location Hg(0)l was distributed throughout 3.2 meters of core whereas the core from a location only 12 meters away only contained Hg(0)l in 0.3 m zone of the core. Sequential extractions, used to examine the forms of Hg in the soils, indicated that at depths within the core that have low Hg concentrations organically associated Hg is dominant. Soil from the zone of groundwater inundation showed reduced characteristics and the Hg is likely present as Hg-sulfide species. At this location it appears that Hg transported within the groundwater is a source of Hg to the soil. Overall the characterization of Hg in soils containing Hg(0) l is difficult due to the heterogeneous distribution within the soils and this challenge is enhanced in industrial facilities in which

Disturbed soil characterization workshop: post-meeting summary

NASA Astrophysics Data System (ADS)

Cathcart, J. Michael

2010-04-01

Disturbance of ground surfaces can arise from a variety of processes, both manmade and natural. Burying landmines, vehicle movement, and walking are representative examples of processes that disturb ground surfaces. The nature of the specific disturbance process can lead to the observables that can aid the detection and identification of that process. While much research has been conducted in this area, fundamental questions related to the remote detection and characterization of disturbed soil surfaces remain unanswered. Under the sponsorship of the Army Research Office (ARO), the Night Vision and Electronic Sensors Directorate (NVESD), and the U.S. Army Corps of Engineers (USACE) Engineering Research and Development Center (ERDC), Georgia Tech hosted a workshop to address Remote Sensing Methods for Disturbed Soil Characterization. The workshop was held January 15-17, 2008 in Atlanta. The primary objective of this workshop was to take a new look at the disturbed soil problem in general as well as its relation to buried explosive detection and other manmade disturbances. In particular, the participants sought to outline the basic science and technology questions that need to be addressed across the full spectrum of military applications to fully exploit this phenomenon. This presentation will outline the approach taken during the workshop and provide a summary of the conclusions.

Imaging and Analytical Approaches for Characterization of Soil Mineral Weathering

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

Dohnalkova, Alice; Arey, Bruce; Varga, Tamas

Soil minerals weathering is the primary natural source of nutrients necessary to sustain productivity in terrestrial ecosystems. Soil microbial communities increase soil mineral weathering and mineral-derived nutrient availability through physical and chemical processes. Rhizosphere, the zone immediately surrounding plant roots, is a biogeochemical hotspot with microbial activity, soil organic matter production, mineral weathering, and secondary phase formation all happening in a small temporally ephemeral zone of steep geochemical gradients. The detailed exploration of the micro-scale rhizosphere is essential to our better understanding of large-scale processes in soils, such as nutrient cycling, transport and fate of soil components, microbial-mineral interactions, soilmore » erosion, soil organic matter turnover and its molecular-level characterization, and predictive modeling.« less

Characterization of soils from an industrial complex contaminated with elemental mercury

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

Miller, Carrie L., E-mail: millercl@ornl.gov; Watson, David B.; Lester, Brian P.

2013-08-15

Historical use of liquid elemental mercury (Hg(0){sub l}) at the Y-12 National Security Complex in Oak Ridge, TN, USA, resulted in large deposits of Hg(0){sub l} in the soils. The fate and distribution of the spilled Hg(0) are not well characterized. In this study we evaluated analytical tools for characterizing the speciation of Hg in the contaminated soils and then used the analytical techniques to examine the speciation of Hg in two soil cores collected at the site. These include x-ray fluorescence (XRF), soil Hg(0) headspace analysis, and total Hg determination by acid digestion coupled with cold vapor atomic absorptionmore » (HgT). XRF was not found to be suitable for evaluating Hg concentrations in heterogeneous soils containing low concentration of Hg or Hg(0) because Hg concentrations determined using this method were lower than those determined by HgT analysis and the XRF detection limit is 20 mg/kg. Hg(0){sub g} headspace analysis coupled with HgT measurements yielded good results for examining the presence of Hg(0){sub l} in soils and the speciation of Hg. The two soil cores are highly heterogeneous in both the depth and extent of Hg contamination, with Hg concentrations ranging from 0.05 to 8400 mg/kg. In the first core, Hg(0){sub l} was distributed throughout the 3.2 m depth, whereas the second core, from a location 12 m away, contained Hg(0){sub l} in a 0.3 m zone only. Sequential extractions showed organically associated Hg dominant at depths with low Hg concentration. Soil from the zone of groundwater saturation showed reducing conditions and the Hg is likely present as Hg-sulfide species. At this depth, lateral Hg transport in the groundwater may be a source of Hg detected in the soil at the deeper soil depths. Overall, characterization of soils containing Hg(0){sub l} is difficult because of the heterogeneous distribution of Hg within the soils. This is exacerbated in industrial facilities where fill materials make up much of the soils and

The Influence of Basic Physical Properties of Soil on its Electrical Resistivity Value under Loose and Dense Condition

NASA Astrophysics Data System (ADS)

Abidin, M. H. Z.; Ahmad, F.; Wijeyesekera, D. C.; Saad, R.

2014-04-01

Electrical resistivity technique has become a famous alternative tool in subsurface characterization. In the past, several interpretations of electrical resistivity results were unable to be delivered in a strong justification due to lack of appreciation of soil mechanics. Traditionally, interpreters will come out with different conclusion which commonly from qualitative point of view thus creating some uncertainty regarding the result reliability. Most engineers desire to apply any techniques in their project which are able to provide some clear justification with strong, reliable and meaningful results. In order to reduce the problem, this study presents the influence of basic physical properties of soil due to the electrical resistivity value under loose and dense condition. Two different conditions of soil embankment model were tested under electrical resistivity test and basic geotechnical test. It was found that the electrical resistivity value (ERV, ρ) was highly influenced by the variations of soil basic physical properties (BPP) with particular reference to moisture content (w), densities (ρbulk/dry), void ratio (e), porosity (η) and particle grain fraction (d) of soil. Strong relationship between ERV and BPP can be clearly presents such as ρ ∞ 1/w, ρ ∞ 1/ρbulk/dry, ρ ∞ e and ρ ∞ η. This study therefore contributes a means of ERV data interpretation using BPP in order to reduce ambiguity of ERV result and interpretation discussed among related persons such as geophysicist, engineers and geologist who applied these electrical resistivity techniques in subsurface profile assessment.

Profile of a city: characterizing and classifying urban soils in the city of Ghent

NASA Astrophysics Data System (ADS)

Delbecque, Nele; Verdoodt, Ann

2017-04-01

Worldwide, urban lands are expanding rapidly. Conversion of agricultural and natural landscapes to urban fabric can strongly influence soil properties through soil sealing, excavation, leveling, contamination, waste disposal and land management. Urban lands, often characterized by intensive use, need to deliver many production, ecological and cultural ecosystem services. To safeguard this natural capital for future generations, an improved understanding of biogeochemical characteristics, processes and functions of urban soils in time and space is essential. Additionally, existing (inter)national soil classification systems, based on the identification of soil genetic horizons, do not always allow a functional classification of urban soils. This research aims (1) to gain insight into urban soils and their properties in the city of Ghent (Belgium), and (2) to develop a procedure to functionally incorporate urban soils into existing (inter)national soil classification systems. Undisturbed soil cores (depth up to 1.25 m) are collected at 15 locations in Ghent with different times since development and land uses. Geotek MSCL-scans are taken to determine magnetic susceptibility and gamma density and to obtain high resolution images. Physico-chemical characterization of the soil cores is performed by means of detailed soil profile descriptions, traditional lab analyses, as well as proximal soil sensing techniques (XRF). The first results of this research will be presented and critically discussed to improve future efforts to characterize, classify and evaluate urban soils and their ecosystem services.

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

Non-Invasive Methods to Characterize Soil-Plant Interactions at Different Scales

NASA Astrophysics Data System (ADS)

Javaux, M.; Kemna, A.; Muench, M.; Oberdoerster, C.; Pohlmeier, A.; Vanderborght, J.; Vereecken, H.

2006-05-01

Root water uptake is a dynamic and non-linear process, which interacts with the soil natural variability and boundary conditions to generate heterogeneous spatial distributions of soil water. Soil-root fluxes are spatially variable due to heterogeneous gradients and hydraulic connections between soil and roots. While 1-D effective representation of the root water uptake has been successfully applied to predict transpiration and average water content profiles, finer spatial characterization of the water distribution may be needed when dealing with solute transport. Indeed, root water uptake affects the water velocity field, which has an effect on solute velocity and dispersion. Although this variability originates from small-scale processes, these may still play an important role at larger scales. Therefore, in addition to investigate the variability of the soil hydraulic properties, experimental and numerical tools for characterizing root water uptake (and its effects on soil water distribution) from the pore to the field scales are needed to predict in a proper way the solute transport. Obviously, non-invasive and modeling techniques which are helpful to achieve this objective will evolve with the scale of interest. At the pore scale, soil structure and root-soil interface phenomena have to be investigated to understand the interactions between soil and roots. Magnetic resonance imaging may help to monitor water gradients and water content changes around roots while spectral induced polarization techniques may be used to characterize the structure of the pore space. At the column scale, complete root architecture of small plants and water content depletion around roots can be imaged by magnetic resonance. At that scale, models should explicitly take into account the three-dimensional gradient dependency of the root water uptake, to be able to predict solute transport. At larger scales however, simplified models, which implicitly take into account the heterogeneous

Effects of Sludge Compost on EC value of Saline Soil and Plant Height of Medicago

NASA Astrophysics Data System (ADS)

Sun, Chongyang; Zhao, Ke; Chen, Xing; Wang, Xiaohui

2017-12-01

In this study, the effects of sludge composting on the EC value of saline soil and the response to Medicago plant height were studied by planting Medicago with pots for 45 days in different proportions as sludge composting with saline soil. The results showed that the EC value of saline soil did not change obviously with the increase of fertilization ratio,which indicated that the EC value of saline soil was close to that of the original soil. The EC decreased by 31.45% at fertilization ratio of 40%. The height of Medicago reached the highest at 40% fertilization ratio, and that was close to 60% fertilization ratio, and the difference was significant with other treatments. By comprehensive analyse and compare,the optimum application rate of sludge compost was 40% under this test condition.

Characterization of Soil Moisture Level for Rice and Maize Crops using GSM Shield and Arduino Microcontroller

NASA Astrophysics Data System (ADS)

Gines, G. A.; Bea, J. G.; Palaoag, T. D.

2018-03-01

Soil serves a medium for plants growth. One factor that affects soil moisture is drought. Drought has been a major cause of agricultural disaster. Agricultural drought is said to occur when soil moisture is insufficient to meet crop water requirements, resulting in yield losses. In this research, it aimed to characterize soil moisture level for Rice and Maize Crops using Arduino and applying fuzzy logic. System architecture for soil moisture sensor and water pump were the basis in developing the equipment. The data gathered was characterized by applying fuzzy logic. Based on the results, applying fuzzy logic in validating the characterization of soil moisture level for Rice and Maize crops is accurate as attested by the experts. This will help the farmers in monitoring the soil moisture level of the Rice and Maize crops.

Hydraulic characterization of a sealed loamy soil in a Mediterranean vineyard

NASA Astrophysics Data System (ADS)

Alagna, Vincenzo; Di Prima, Simone; Bagarello, Vincenzo; Guaitoli, Fabio; Iovino, Massimo; Keesstra, Saskia; Cerdà, Artemi

2017-04-01

Water infiltration measurements constitute a common way for an indirect characterization of sealed/crusted soils (Alagna et al., 2013). The Beerkan Estimation of Soil Transfer (BEST) parameters procedure by Lassabatere et al. (2006) is very attractive for practical use since it allows an estimation of both the soil water retention and hydraulic conductivity functions. The BEST method considers certain analytical formulae for the hydraulic characteristic curves and estimates their shape parameters, which are texture dependent, from particle-size analysis by physical-empirical pedotransfer functions. Structure dependent scale parameters are estimated by a beerkan experiment, i.e. a three-dimensional (3D) field infiltration experiment at ideally zero pressure head. BEST substantially facilitates the hydraulic characterization of unsaturated soils, and it is gaining popularity in soil science (Bagarello et al., 2014a; Di Prima, 2015; Di Prima et al., 2016b). Bagarello et al. (2014b) proposed a beerkan derived procedure to explain surface runoff and disturbance phenomena at the soil surface occurring during intense rainfall events. Di Prima et al. (2016a) applied this methodology in a vineyard with a sandy-loam texture. These authors compared this simple methodology with rainfall simulation experiments establishing a physical link between the two methodologies through the kinetic energy of the rainfall and the gravitational potential energy of the water used for the beerkan runs. They also indirectly demonstrated the occurrence of a certain degree of compaction and mechanical breakdown using a minidisk infiltrometer (Decagon, 2014). With this device, they reported a reduction of the unsaturated hydraulic conductivity by 2.3 times, due to the seal formation. The ability of the BEST method to distinguish between crusted and non-crusted soils was demonstrated by Souza et al. (2014). However, the potential of the beerkan runs to detect the effect of the seal on flow and

Characterization of the Resource Potential of Martian Soil using the Integrated Dust/Soil Experiment Package (IDEP)

NASA Technical Reports Server (NTRS)

Cooper, Bonnie L.; Mckay, David S.; Allen, Carlton C.; Hoffman, John H.; Gittleman, Mark E.

1997-01-01

The Integrated Dust/Soil Experiment Package (IDEP) is a suite of instruments that can detect and quantify the abundances of useful raw materials on Mars. We focus here on its capability for resource characterization in the martian soil; however, it is also capable of detecting and quantifying gases in the atmosphere. This paper describes the scientific rationale and the engineering design behind the IDEP.

Characterization of agricultural land using singular value decomposition

NASA Astrophysics Data System (ADS)

Herries, Graham M.; Danaher, Sean; Selige, Thomas

1995-11-01

A method is defined and tested for the characterization of agricultural land from multi-spectral imagery, based on singular value decomposition (SVD) and key vector analysis. The SVD technique, which bears a close resemblance to multivariate statistic techniques, has previously been successfully applied to problems of signal extraction for marine data and forestry species classification. In this study the SVD technique is used as a classifier for agricultural regions, using airborne Daedalus ATM data, with 1 m resolution. The specific region chosen is an experimental research farm in Bavaria, Germany. This farm has a large number of crops, within a very small region and hence is not amenable to existing techniques. There are a number of other significant factors which render existing techniques such as the maximum likelihood algorithm less suitable for this area. These include a very dynamic terrain and tessellated pattern soil differences, which together cause large variations in the growth characteristics of the crops. The SVD technique is applied to this data set using a multi-stage classification approach, removing unwanted land-cover classes one step at a time. Typical classification accuracy's for SVD are of the order of 85-100%. Preliminary results indicate that it is a fast and efficient classifier with the ability to differentiate between crop types such as wheat, rye, potatoes and clover. The results of characterizing 3 sub-classes of Winter Wheat are also shown.

Evaluation of Electromagnetic Induction to Characterize and Map Sodium-Affected Soils in the Northern Great Plains of the United States

NASA Astrophysics Data System (ADS)

Brevik, E. C.; Heilig, J.; Kempenich, J.; Doolittle, J.; Ulmer, M.

2012-04-01

Sodium-affected soils (SAS) cover over 4 million hectares in the Northern Great Plains of the United States. Improving the classification, interpretation, and mapping of SAS is a major goal of the United States Department of Agriculture-Natural Resource Conservation Service (USDA-NRCS) as Northern Great Plains soil surveys are updated. Apparent electrical conductivity (ECa) as measured with ground conductivity meters has shown promise for mapping SAS, however, this use of this geophysical tool needs additional evaluation. This study used an EM-38 MK2-2 meter (Geonics Limited, Mississauga, Ontario), a Trimble AgGPS 114 L-band DGPS (Trimble, Sunnyvale, CA) and the RTmap38MK2 program (Geomar Software, Inc., Mississauga, Ontario) on an Allegro CX field computer (Juniper Systems, North Logan, UT) to collect, observe, and interpret ECa data in the field. The ECa map generated on-site was then used to guide collection of soil samples for soil characterization and to evaluate the influence of soil properties in SAS on ECa as measured with the EM-38MK2-2. Stochastic models contained in the ESAP software package were used to estimate the SAR and salinity levels from the measured ECa data in 30 cm depth intervals to a depth of 90 cm and for the bulk soil (0 to 90 cm). This technique showed promise, with meaningful spatial patterns apparent in the ECa data. However, many of the stochastic models used for salinity and SAR for individual depth intervals and for the bulk soil had low R-squared values. At both sites, significant variability in soil clay and water contents along with a small number of soil samples taken to calibrate the ECa values to soil properties likely contributed to these low R-squared values.

Mineralogical and Chemical Characterization of Lunar Highland Regolith: Lessons Learned from Mare Soils

NASA Technical Reports Server (NTRS)

Taylor, L. A.; Cahill, J. T.; Patchen, A.; Pieters, C.; Morris, R.; Keller, L. P.; McKay, D. S.

2001-01-01

The Lunar Soil Characterization Consortium has begun study of the <45 m fractions of ten representative highland soils, chosen for their contrasting maturities. Difficulties are addressed in the modal and chemical analyses of these highland soils. Additional information is contained in the original extended abstract.

Direct soil contact values for ecological receptors exposed to weathered petroleum hydrocarbon (PHC) fraction 2.

PubMed

Angell, Robin A; Kullman, Steve; Shrive, Emma; Stephenson, Gladys L; Tindal, Miles

2012-11-01

Ecological tier 1 Canada-wide standards (CWS) for petroleum hydrocarbon (PHC) fraction 2 (F2; >nC10-C16) in soil were derived using ecotoxicological assessment endpoints (effective concentrations [ECs]/lethal concentrations [LCs]/inhibitory concentrations, 25% [IC25s]) with freshly spiked (fresh) fine- and coarse-grained soils. These soil standards might be needlessly conservative when applied to field samples with weathered hydrocarbons. The purpose of the present study was to assess the degradation and toxicity of weathered PHC F2 in a fine-grained soil and to derive direct soil contact values for ecological receptors. Fine-grained reference soils were spiked with distilled F2 and weathered for 183 d. Toxicity tests using plants and invertebrates were conducted with the weathered F2-spiked soils. Endpoint EC/IC25s were calculated and used to derive soil standards for weathered F2 in fine-grained soil protective of ecological receptors exposed via direct soil contact. The values derived for weathered F2 were less restrictive than current ecological tier 1 CWS for F2 in soil. Copyright © 2012 SETAC.

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.

Residential surface soil guidance values applied worldwide to the original 2001 Stockholm Convention POP pesticides.

PubMed

Jennings, Aaron A; Li, Zijian

2015-09-01

Surface soil contamination is a worldwide problem. Many regulatory jurisdictions attempt to control human exposures with regulatory guidance values (RGVs) that specify a soil's maximum allowable concentration. Pesticides are important soil contaminants because of their intentional toxicity and widespread surface soil application. Worldwide, at least 174 regulatory jurisdictions from 54 United Nations member states have published more than 19,400 pesticide RGVs for at least 739 chemically unique pesticides. This manuscript examines the variability of the guidance values that are applied worldwide to the original 2001 Stockholm Convention persistent organic pollutants (POP) pesticides (Aldrin, Chlordane, DDT, Dieldrin, Endrin, Heptachlor, Mirex, and Toxaphene) for which at least 1667 RGVs have been promulgated. Results indicate that the spans of the RGVs applied to each of these pesticides vary from 6.1 orders of magnitude for Toxaphene to 10.0 orders of magnitude for Mirex. The distribution of values across these value spans resembles the distribution of lognormal random variables, but also contain non-random value clusters. Approximately 40% of all the POP RGVs fall within uncertainty bounds computed from the U.S. Environmental Protection Agency (USEPA) RGV cancer risk model. Another 22% of the values fall within uncertainty bounds computed from the USEPA's non-cancer risk model, but the cancer risk calculations yield the binding (lowest) value for all POP pesticides except Endrin. The results presented emphasize the continued need to rationalize the RGVs applied worldwide to important soil contaminants. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of soil properties on the toxicity of Pb: assessment of the appropriateness of guideline values.

PubMed

Romero-Freire, A; Martin Peinado, F J; van Gestel, C A M

2015-05-30

Soil contamination with lead is a worldwide problem. Pb can cause adverse effects, but its mobility and availability in the terrestrial environment are strongly controlled by soil properties. The present study investigated the influence of different soil properties on the solubility of lead in laboratory spiked soils, and its toxicity in three bioassays, including Lactuca sativa root elongation and Vibrio fischeri illumination tests applied to aqueous extracts and basal soil respiration assays. Final aim was to compare soil-dependent toxicity with guideline values. The L. sativa bioassay proved to be more sensitive to Pb toxicity than the V. fischeri and soil respiration tests. Toxicity was significantly correlated with soil properties, with soil pH, carbonate and organic carbon content being the most important factors. Therefore, these variables should be considered when defining guideline values. Copyright © 2015 Elsevier B.V. All rights reserved.

The Value of SMAP Soil Moisture Observations For Agricultural Applications

NASA Astrophysics Data System (ADS)

Mladenova, I. E.; Bolten, J. D.; Crow, W.; Reynolds, C. A.

2017-12-01

Knowledge of the amount of soil moisture (SM) in the root zone (RZ) is critical source of information for crop analysts and agricultural agencies as it controls crop development and crop condition changes and can largely impact end-of-season yield. Foreign Agricultural Services (FAS), a subdivision of U.S. Department of Agriculture (USDA) that is in charge with providing information on current and expected global crop supply and demand estimates, has been relying on RZSM estimates generated by the modified two-layer Palmer model, which has been enhanced to allow the assimilation of satellite-based soil moisture data. Generally the accuracy of model-based soil moisture estimates is dependent on the precision of the forcing data that drives the model and more specifically, the accuracy of the precipitation data. Data assimilation gives the opportunity to correct for such precipitation-related inaccuracies and enhance the quality of the model estimates. Here we demonstrate the value of ingesting passive-based soil moisture observations derived from the Soil Moisture Active Passive (SMAP) mission. In terms of agriculture, general understanding is that the change in soil moisture conditions precede the change in vegetation status, suggesting that soil moisture can be used as an early indicator of expected crop conditions. Therefore, we assess the accuracy of the SMAP enhanced Palmer model by examining the lag rank cross-correlation coefficient between the model generated soil moisture observations and the Normalized Difference Vegetation Index (NDVI).

Soil Physical, Chemical, and Thermal Characterization, Teller Road Site, Seward Peninsula, Alaska, 2016

DOE Data Explorer

Graham, David; Kholodov, Alexander; Wilson, Cathy; Moon, Ji-Won; Romanovsky, Vladimir; Busey, Bob

2018-02-05

This dataset provides the results of physical, chemical, and thermal characterization of soils at the Teller Road Site, Seward Peninsula, Alaska. Soil pits were dug from 7-14 September 2016 at designated Intensive Stations 2 through 9 at the Teller Road MM 27 Site. This dataset includes field observations and descriptions of soil layers or horizons, field measurements of soil volumetric water content, soil temperature, thermal conductivity, and heat capacity. Laboratory measurements of soil properties include gravimetric water content, bulk density, volumetric water content, and total carbon and nitrogen.

Soil Physical, Chemical, and Thermal Characterization, Council Road Site, Seward Peninsula, Alaska, 2016

DOE Data Explorer

Alexander Kholodov; David Graham; Ji-Won Moon

2018-01-22

This dataset provides the results of physical, chemical, and thermal characterization of soils at the Council Road Site at MM71, Seward Peninsula, Alaska. Soil pits were dug on 11 September 2016 at three sites. This dataset includes field observations and descriptions of soil layers or horizons, field measurements of soil volumetric water content, soil temperature, thermal conductivity, and heat capacity. Laboratory measurements of soil properties include gravimetric water content, bulk density, volumetric water content, total carbon and nitrogen, and elemental composition from X-ray fluorescence for some elements.

Value of Available Global Soil Moisture Products for Agricultural Monitoring

NASA Astrophysics Data System (ADS)

Mladenova, Iliana; Bolten, John; Crow, Wade; de Jeu, Richard

2016-04-01

The first operationally derived and publicly distributed global soil moil moisture product was initiated with the launch of the Advanced Scanning Microwave Mission on the NASA's Earth Observing System Aqua satellite (AMSR-E). AMSR-E failed in late 2011, but its legacy is continued by AMSR2, launched in 2012 on the JAXA Global Change Observation Mission-Water (GCOM-W) mission. AMSR is a multi-frequency dual-polarization instrument, where the lowest two frequencies (C- and X-band) were used for soil moisture retrieval. Theoretical research and small-/field-scale airborne campaigns, however, have demonstrated that soil moisture would be best monitored using L-band-based observations. This consequently led to the development and launch of the first L-band-based mission-the ESA's Soil Moisture Ocean Salinity (SMOS) mission (2009). In early 2015 NASA launched the second L-band-based mission, the Soil Moisture Active Passive (SMAP). These satellite-based soil moisture products have been demonstrated to be invaluable sources of information for mapping water stress areas, crop monitoring and yield forecasting. Thus, a number of agricultural agencies routinely utilize and rely on global soil moisture products for improving their decision making activities, determining global crop production and crop prices, identifying food restricted areas, etc. The basic premise of applying soil moisture observations for vegetation monitoring is that the change in soil moisture conditions will precede the change in vegetation status, suggesting that soil moisture can be used as an early indicator of expected crop condition change. Here this relationship was evaluated across multiple microwave frequencies by examining the lag rank cross-correlation coefficient between the soil moisture observations and the Normalized Difference Vegetation Index (NDVI). A main goal of our analysis is to evaluate and inter-compare the value of the different soil moisture products derived using L-band (SMOS

Characterization of Minerals: From the Classroom to Soils to Talc Deposits

ERIC Educational Resources Information Center

McNamee, Brittani D.

2013-01-01

This dissertation addresses different methods and challenges surrounding characterizing and identifying minerals in three environments: in the classroom, in soils, and in talc deposits. A lab manual for a mineralogy and optical mineralogy course prepares students for mineral characterization and identification by giving them the methods and tools…

Polybrominated diphenyl ethers (PBDEs) concentration in soil from San Luis Potosi, Mexico: levels and ecological and human health risk characterization.

PubMed

Pérez-Vázquez, Francisco J; Orta-García, Sandra T; Ochoa-Martínez, Ángeles C; Pruneda-Álvarez, Lucia G; Ruiz-Vera, Tania; Jiménez-Avalos, Jorge Armando; González-Palomo, Ana K; Pérez-Maldonado, Iván N

2016-01-01

The aim of this study was to assess the levels of polybrominated diphenyl ethers (PBDEs) in soils from the city of San Luis Potosi in Mexico and perform an ecological and human health risk characterization. In order to confirm the presence of PBDEs, outdoor surface soil samples were collected and the concentrations of PBDEs in urban, industrial, agricultural, and brick kiln industry areas were determined. The mean total PBDEs levels obtained in the study sites were 25.0 ± 39.5 μg/kg (geometric mean ± standard deviation) in the brick kiln industry zone; 34.5 ± 36.0 μg/kg in the urban zone; 8.00 ± 7.10 μg/kg in the industrial zone and 16.6 ± 15.3 μg/kg in the agricultural zone. The ecological and human health risk characterization showed relatively low-hazard quotient values. However, the moderately high PBDEs levels found in soils highlight the necessity to establish a systematic monitoring process for PBDEs in environmental and biological samples.

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

Mercury Inhibits Soil Enzyme Activity in a Lower Concentration than the Guideline Value.

PubMed

Mahbub, Khandaker Rayhan; Krishnan, Kannan; Megharaj, Mallavarapu; Naidu, Ravi

2016-01-01

Three soil types - neutral, alkaline and acidic were experimentally contaminated with nine different concentrations of inorganic mercury (0, 5, 10, 50, 100, 150, 200, 250, 300 mg/kg) to derive effective concentrations of mercury that exert toxicity on soil quality. Bioavailability of mercury in terms of water solubility was lower in acidic soil with higher organic carbon. Dehydrogenase enzyme activity and nitrification rate were chosen as indicators to assess soil quality. Inorganic mercury significantly inhibited (p < 0.001) microbial activities in the soils. The critical mercury contents (EC10) were found to be less than the available safe limits for inorganic mercury which demonstrated inadequacy of existing guideline values.

Reference values for heavy metals in soils of the Brazilian agricultural frontier in Southwestern Amazônia.

PubMed

dos Santos, Sabrina Novaes; Alleoni, Luís Reynaldo Ferracciú

2013-07-01

Guideline values are used to identify polluted or contaminated areas based on background values. Brazilian law establishes three guideline values for pollutants: a quality reference value (QRV), a prevention value, and an intervention value. Reference values refer to the natural concentration of an element or a substance in soils that have not been modified by anthropogenic impacts. These values inform assessments of soil quality and are used to establish maximum permissible limits. The objective of this study was to determine the natural levels and reference values for Cd, Co, Cr, Cu, Ni, Pb, and Zn in samples from the surface layer (0-20 cm) of 19 representative soils of the states of Mato Grosso and Rondônia, on Brazil's agricultural frontier. Pseudo-total metal concentrations were obtained following microwave-assisted digestion using the aqua regia and EPA3051 methods. QRVs were calculated for each element as the 75th and 90th percentiles of the frequency distribution of the data. Natural levels of heavy metals in the soil samples followed the order: Cr > Zn > Cu > Co > Pb > Ni > and Cd (aqua regia) and Cr > Co > Cu > Pb > Zn > Ni > Cd (EPA3051). These values are generally lower than those reported in the Brazilian and international literature, which highlights the importance of establishing reference values for each state or for each soil type, taking into account the geomorphological, pedological, and geological diversity of the region under study.

Effect of Spatial Resolution for Characterizing Soil Properties from Imaging Spectrometer Data

NASA Astrophysics Data System (ADS)

Dutta, D.; Kumar, P.; Greenberg, J. A.

2015-12-01

The feasibility of quantifying soil constituents over large areas using airborne hyperspectral data [0.35 - 2.5 μm] in an ensemble bootstrapping lasso algorithmic framework has been demonstrated previously [1]. However the effects of coarsening the spatial resolution of hyperspectral data on the quantification of soil constituents are unknown. We use Airborne Visible Infrared Imaging Spectrometer (AVIRIS) data collected at 7.6m resolution over Birds Point New Madrid (BPNM) floodway for up-scaling and generating multiple coarser resolution datasets including the 60m Hyperspectral Infrared Imager (HyspIRI) like data. HyspIRI is a proposed visible shortwave/thermal infrared mission, which will provide global data over a spectral range of 0.35 - 2.5μm at a spatial resolution of 60m. Our results show that the lasso method, which is based on point scale observational data, is scalable. We found consistent good model performance (R2) values (0.79 < R2 < 0.82) and correct classifications as per USDA soil texture classes at multiple spatial resolutions. The results further demonstrate that the attributes of the pdf for different soil constituents across the landscape and the within-pixel variance are well preserved across scales. Our analysis provides a methodological framework with a sufficient set of metrics for assessing the performance of scaling up analysis from point scale observational data and may be relevant for other similar remote sensing studies. [1] Dutta, D.; Goodwell, A.E.; Kumar, P.; Garvey, J.E.; Darmody, R.G.; Berretta, D.P.; Greenberg, J.A., "On the Feasibility of Characterizing Soil Properties From AVIRIS Data," Geoscience and Remote Sensing, IEEE Transactions on, vol.53, no.9, pp.5133,5147, Sept. 2015. doi: 10.1109/TGRS.2015.2417547.

Characterization of sorption properties of selected soils from Lublin region by using water vapour adsorption method

NASA Astrophysics Data System (ADS)

Skic, Kamil; Boguta, Patrycja; Sokołowska, Zofia

2016-04-01

*The studies were carried out within the framework of a research project. The project was financed from funds of National Science Center on the base of decision number DEC-2013/11/D/NZ9/02545 Among many methods proposed to study sorption properties of soils an analysis of adsorption/ desorption isotherm is probably the easiest and most convenient one. It characterizes both quantity and quality of mineral and organic components and also their physical and physicochemical properties. The main aim of this study is comparison of sorption properties of selected Polish soils by using water vapour adsorption method. Samples were taken from the depth of 0-20 cm, from the Lublin region, eastern Poland. Soils were selected on the basis of their different physicochemical properties and were classified as: Haplic Fluvisol, Haplic Chernozem, Mollic Gleysol, Rendzic Phaeozem, Stagnic Luvisol, Haplic Cambisol (WG WRB 2006). Data taken from experimental adsorption isotherms were used to determine parameters of monolayer capacity, specific surface area and the total amount of vapour adsorbed at relative pressure of 0.974. Obtained adsorption and desorption isotherms reviled that adsorbate molecules interacted with the soil particles in different extent. Similar monolayer capacity was observed for Haplic Fluvisol, Haplic Chernozem and Stagnic Luvisol, while for Mollic Gleysol was more than 4 times higher. Mollic Gleysol was also characterized by highest values of specific surface area as well as quantity of adsorbed vapour at relative pressure of 0.974. Higher sorption was caused by presence of soil colloids which contains functional groups of a polar nature (mainly hydroxyls, phenolic and carboxyls). These groups similarly to silicates, oxides, hydratable cations as well as electric charge form adsorption centres for water vapour molecules.

Distributed Soil Moisture Estimation in a Mountainous Semiarid Basin: Constraining Soil Parameter Uncertainty through Field Studies

NASA Astrophysics Data System (ADS)

Yatheendradas, S.; Vivoni, E.

2007-12-01

A common practice in distributed hydrological modeling is to assign soil hydraulic properties based on coarse textural datasets. For semiarid regions with poor soil information, the performance of a model can be severely constrained due to the high model sensitivity to near-surface soil characteristics. Neglecting the uncertainty in soil hydraulic properties, their spatial variation and their naturally-occurring horizonation can potentially affect the modeled hydrological response. In this study, we investigate such effects using the TIN-based Real-time Integrated Basin Simulator (tRIBS) applied to the mid-sized (100 km2) Sierra Los Locos watershed in northern Sonora, Mexico. The Sierra Los Locos basin is characterized by complex mountainous terrain leading to topographic organization of soil characteristics and ecosystem distributions. We focus on simulations during the 2004 North American Monsoon Experiment (NAME) when intensive soil moisture measurements and aircraft- based soil moisture retrievals are available in the basin. Our experiments focus on soil moisture comparisons at the point, topographic transect and basin scales using a range of different soil characterizations. We compare the distributed soil moisture estimates obtained using (1) a deterministic simulation based on soil texture from coarse soil maps, (2) a set of ensemble simulations that capture soil parameter uncertainty and their spatial distribution, and (3) a set of simulations that conditions the ensemble on recent soil profile measurements. Uncertainties considered in near-surface soil characterization provide insights into their influence on the modeled uncertainty, into the value of soil profile observations, and into effective use of on-going field observations for constraining the soil moisture response uncertainty.

Synthesis of soil-hydraulic properties and infiltration timescales in wildfire-affected soils

USGS Publications Warehouse

Ebel, Brian A.; Moody, John A.

2017-01-01

We collected soil-hydraulic property data from the literature for wildfire-affected soils, ash, and unburned soils. These data were used to calculate metrics and timescales of hydrologic response related to infiltration and surface runoff generation. Sorptivity (S) and wetting front potential (Ψf) were significantly different (lower) in burned soils compared with unburned soils, whereas field-saturated hydraulic conductivity (Kfs) was not significantly different. The magnitude and duration of the influence of capillarity during infiltration was greatly reduced in burned soils, causing faster ponding times in response to rainfall. Ash had large values of S and Kfs but moderate values of Ψf, compared with unburned and burned soils, indicating ash has long ponding times in response to rainfall. The ratio of S2/Kfs was nearly constant (~100 mm) for unburned soils but more variable in burned soils, suggesting that unburned soils have a balance between gravity and capillarity contributions to infiltration that may depend on soil organic matter, whereas in burned soils the gravity contribution to infiltration is greater. Changes in S and Kfs in burned soils act synergistically to reduce infiltration and accelerate and amplify surface runoff generation. Synthesis of these findings identifies three key areas for future research. First, short timescales of capillary influences on infiltration indicate the need for better measurements of infiltration at times less than 1 min to accurately characterize S in burned soils. Second, using parameter values, such as Ψf, from unburned areas could produce substantial errors in hydrologic modeling when used without adjustment for wildfire effects, causing parameter compensation and resulting underestimation of Kfs. Third, more thorough measurement campaigns that capture soil-structural changes, organic matter impacts, quantitative water repellency trends, and soil-water content along with soil-hydraulic properties could drive the

Spatial characterization of soil properties and influence in soil formation in oak-grassland of Sierra Morena, S Spain

NASA Astrophysics Data System (ADS)

Román-Sánchez, Andrea; Cáceres, Francisco; Pédèches, Remi; Giráldez Cervera, Juan Vicente; Vanwalleghem, Tom

2016-04-01

The Mediterranean oak-grassland ecosystem is very important for the rural economy and for the biodiversity of south-western European countries like Spain and Portugal. Nevertheless these ecosystems are not well characterized especially their soils. In this report soil carbon has been evaluated and related to other properties. The principal factors controlling the structure, productivity and evolution of forest ecosystems are bedrock, climate, relief, vegetation and time. Soil carbon has an important influence in the soil and ecosystem structures. The purpose of this study is to determine the relationship between relief, soil properties, spatial distribution of soil carbon and their influence in soil formation and geomorphology. This work is part of another study which aims to elucidate the processes involved in the soil formation and to examine their behaviour on long-term with a modelling. In our study area, located in oak-grassland of Sierra Morena, in Cordoba, S Spain, have been studied 67 points at 6 depths in 262 hectares in order to determine carbon content varying between 0-6%, soil properties such as soil depth between 0-4 m, horizon depth and the rocks amount in surface. The relationship between the soil carbon, soil properties and the relief characteristic like slope, aspect, curvature can shed light the processes that affect the mechanisms of bedrock weathering and their interrelationship with geomorphological processes.

Occurrence and characterization of hitherto unknown Streptomyces species in semi-arid soils.

PubMed

Kumar, Surendra; Priya, E; Singh Solanki, Dilip; Sharma, Ruchika; Gehlot, Praveen; Pathak, Rakesh; Singh, S K

2016-09-01

Streptomyces the predominant genus of Actinobacteria and plays an important role in the recycling of soil organic matter and production of important secondary metabolites. The occurrence and diversity assessment of Streptomyces species revealed alkaline and poor nutrient status of soils of semi-arid region of Jodhpur, Rajasthan. The morphological and biochemical characterization of 21 Streptomyces isolates facilitated Genus level identification but were insufficient to designate species. Species designation based on 16S rRNA gene delineated 21 isolates into 14 Streptomyces species. Upon BLAST search, the test isolates exhibited 98 to 100% identities with that of the best aligned sequences of the NCBI database. The GC content of 16S rRNA gene sequences of all the Streptomyces isolates tested ranged from 59.03% to 60.94%. The multiple sequence alignment of all the 21 Streptomyces isolates generated a phylogram with high bootstrap values indicating reliable grouping of isolates based on nucleotide sequence variations by way of insertion, deletion and substitutions and 16S rRNA length polymorphism. Some of the Streptomyces species molecularly identified under present study are reported for the first time from semi-arid region of Jodhpur.

Geochemical characterization of soils of the eastern coast of the Northern Sakhalin Lowland

NASA Astrophysics Data System (ADS)

Zharikova, E. A.

2017-01-01

Concentrations of heavy metals (HMs) were determined in soils of the eastern coast of the Northern Sakhalin Lowland. The total contents of HMs and their distribution in the studied soils differed from those in the world soils. Thus, barium and mercury concentrations exceeded clarke values for the world soils. The reserves of mobile forms of microelements were found to be low. Significant biogenic accumulation in organic soil horizons in the process of soil formation was found for copper, arsenic, and barium.

[Estimation on value of water and soil conservation of agricultural ecosystems in Xi' an metropolitan, Northwest China].

PubMed

Yang, Wen-yan; Zhou, Zhong-xue

2014-12-01

With the urban eco-environment increasingly deteriorating, the ecosystem services provided by modern urban agriculture are exceedingly significant to maintain and build more suitable environment in a city. Taking Xi' an metropolitan as the study area, based on remote sensing data, DEM data and the economic and social statistics data, the water and soil conservation service of the agricultural ecosystems was valued employing the remote sensing and geographic information system method, covering the reduction values on land waste, soil fertility loss and sediment loss from 2000 to 2011, and analyzed its changes in time and space. The results showed that during the study period, the total value of water and soil conservation service provided by agricultural systems in Xi' an metropolitan was increased by 46,086 and 33.008 billion yuan respectively from period of 2000 to 2005 and from 2005 to 2011. The cultivated land (including grains, vegetables and other farming land), forest (including orchard) and grassland provided higher value on the water and soil conservation service than waters and other land use. Ecosystem service value of water and soil conserva- tion provided by agriculture was gradually decreasing from the southern to the northern in Xi' an metropolitan. There were significantly positive relationship between the ecosystem service value and the vegetation coverage. Forest, orchard and grassland distributed intensively in the southern which had higher vegetation coverage than in northern where covered by more cultivated land, sparse forest and scattered orchard. There were significantly negative correlation between the urbanization level and the value of water and soil conservation. The higher level of urbanization, the lower value there was from built-up area to suburban and to countryside within Xi' an metropolitan.

Ecological value of soil carbon management

USDA-ARS?s Scientific Manuscript database

Management of soil carbon is critical to the climate change debate, as well as to the long-term productivity and ecosystem resilience of the biosphere. Soil organic carbon is a key ecosystem property that indicates inherent productivity of land, controls soil biological functioning and diversity, r...

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.

Soils in our big back yard: characterizing the state, vulnerabilities, and opportunities for detecting changes in soil carbon storage

NASA Astrophysics Data System (ADS)

Harden, Jennifer W.; Loiesel, Julie; Ryals, Rebecca; Lawrence, Corey; Blankinship, Joseph; Phillips, Claire; Bond-Lamberty, Ben; Todd-Brown, Katherine; Vargas, Rodrigo; Hugelius, Gustaf; Nave, Luke; Malhotra, Avni; Silver, Whendee; Sanderman, Jon

2017-04-01

A number of diverse approaches and sciences can contribute to a robust understanding of the I. state, II. vulnerabilities, and III. opportunities for soil carbon in context of its potential contributions to the atmospheric C budget. Soil state refers to the current C stock of a given site, region, or ecosystem/landuse type. Soil vulnerabilities refers to the forms and bioreactivity of C stocks, which determine how soil C might respond to climate, disturbance, and landuse perturbations. Opportunities refer to the potential for soils in their current state to increase capacity for and rate of C storage under future conditions, thereby impacting atmospheric C budgets. In order to capture the state, vulnerability, and opportunities for soil C, a robust C accounting scheme must include at least three science needs: (1) a user-friendly and dynamic database with transparent, shared coding in which data layers of solid, liquid, and gaseous phases share relational metadata and allow for changes over time (2) a framework to characterize the capacity and reactivity of different soil types based on climate, historic, and landscape factors (3) a framework to characterize landuse practices and their impact on physical state, capacity/reactivity, and potential for C change. In order to transfer our science information to practicable implementations for land policies, societal and social needs must also include: (1) metrics for landowners and policy experts to recognize conditions of vulnerability or opportunity (2)communication schemes for accessing salient outcomes of the science. Importantly, there stands an opportunity for contributions of data, model code, and conceptual frameworks in which scientists, educators, and decision-makers can become citizens of a shared, scrutinized database that contributes to a dynamic, improved understanding of our soil system.

Application of DRIFTS, 13 C NMR, and py-MBMS to Characterize the Effects of Soil Science Oxidation Assays on Soil Organic Matter Composition in a Mollic Xerofluvent

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

Margenot, Andrew J.; Calderón, Francisco J.; Magrini, Kimberly A.

Chemical oxidations are routinely employed in soil science to study soil organic matter (SOM), and their interpretation could be improved by characterizing oxidation effects on SOM composition with spectroscopy. We investigated the effects of routinely employed oxidants on SOM composition in a Mollic Xerofluvent representative of intensively managed agricultural soils in the California Central Valley. Soil samples were subjected to oxidation by potassium permanganate (KMnO4), sodium hypochlorite (NaOCl), and hydrogen peroxide (H2O2). Additionally, non-oxidized and oxidized soils were treated with hydrofluoric acid (HF) to evaluate reduction of the mineral component to improve spectroscopy of oxidation effects. Oxidized non-HF and HF-treatedmore » soils were characterized by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), 13C cross polarization magic angle spinning (CP-MAS) nuclear magnetic resonance (NMR) spectroscopy, and pyrolysis molecular beam mass spectrometry (py-MBMS), and for particle size distribution (PSD) using laser diffractometry (LD). Across the range of soil organic carbon (OC) removed by oxidations (14-72%), aliphatic C-H stretch at 3000-2800 cm-1 (DRIFTS) decreased with OC removal, and this trend was enhanced by HF treatment due to significant demineralization in this soil (70%). Analysis by NMR spectroscopy was feasible only after HF treatment, and did not reveal trends between OC removal and C functional groups. Pyrolysis-MBMS did not detect differences among oxidations, even after HF treatment of soils. Hydrofluoric acid entailed OC loss (13-39%), and for H2O2 oxidized soils increased C:N and substantially decreased mean particle size. This study demonstrates the feasibility of using HF to improve characterizations of SOM composition following oxidations as practiced in soil science, in particular for DRIFTS. Since OC removal by oxidants, mineral removal by HF, and the interaction of oxidants and HF observed for this soil

Molecular characterization of soil bacterial community in a perhumid, low mountain forest.

PubMed

Lin, Yu-Te; Whitman, William B; Coleman, David C; Chih-Yu, Chiu

2011-01-01

Forest disturbance often results in changes in soil properties and microbial communities. In the present study, we characterized a soil bacterial community subjected to disturbance using 16S rRNA gene clone libraries. The community was from a disturbed broad-leaved, low mountain forest ecosystem at Huoshaoliao (HSL) located in northern Taiwan. This locality receives more than 4,000 mm annual precipitation, one of the highest precipitations in Taiwan. Based on the Shannon diversity index, Chao1 estimator, richness and rarefaction curve analysis, the bacterial community in HSL forest soils was more diverse than those previously investigated in natural and disturbed forest soils with colder or less humid weather conditions. Analysis of molecular variance also revealed that the bacterial community in disturbed soils significantly differed from natural forest soils. Most of the abundant operational taxonomic units (OTUs) in the disturbed soil community at HSL were less abundant or absent in other soils. The disturbances influenced the composition of bacterial communities in natural and disturbed forests and increased the diversity of the disturbed forest soil community. Furthermore, the warmer and humid weather conditions could also increase community diversity in HSL soils.

On the Soil Roughness Parameterization Problem in Soil Moisture Retrieval of Bare Surfaces from Synthetic Aperture Radar

PubMed Central

Verhoest, Niko E.C; Lievens, Hans; Wagner, Wolfgang; Álvarez-Mozos, Jesús; Moran, M. Susan; Mattia, Francesco

2008-01-01

Synthetic Aperture Radar has shown its large potential for retrieving soil moisture maps at regional scales. However, since the backscattered signal is determined by several surface characteristics, the retrieval of soil moisture is an ill-posed problem when using single configuration imagery. Unless accurate surface roughness parameter values are available, retrieving soil moisture from radar backscatter usually provides inaccurate estimates. The characterization of soil roughness is not fully understood, and a large range of roughness parameter values can be obtained for the same surface when different measurement methodologies are used. In this paper, a literature review is made that summarizes the problems encountered when parameterizing soil roughness as well as the reported impact of the errors made on the retrieved soil moisture. A number of suggestions were made for resolving issues in roughness parameterization and studying the impact of these roughness problems on the soil moisture retrieval accuracy and scale. PMID:27879932

Characterization of H2S removal and microbial community in landfill cover soils.

PubMed

Xia, Fang-Fang; Zhang, Hong-Tao; Wei, Xiao-Meng; Su, Yao; He, Ruo

2015-12-01

H2S is a source of odors at landfills and poses a threat to the surrounding environment and public health. In this work, compared with a usual landfill cover soil (LCS), H2S removal and biotransformation were characterized in waste biocover soil (WBS), an alternative landfill cover material. With the input of landfill gas (LFG), the gas concentrations of CH4, CO2, O2, and H2S, microbial community and activity in landfill covers changed with time. Compared with LCS, lower CH4 and H2S concentrations were detected in the WBS. The potential sulfur-oxidizing rate and sulfate-reducing rate as well as the contents of acid-volatile sulfide, SO4(2-), and total sulfur in the WBS and LCS were all increased with the input of LFG. After exposure to LFG for 35 days, the sulfur-oxidizing rate of the bottom layer of the WBS reached 82.5 μmol g dry weight (d.w.)(-1) day(-1), which was 4.3-5.4 times of that of LCS. H2S-S was mainly deposited in the soil covers, while it escaped from landfills to the atmosphere. The adsorption, absorption, and biotransformation of H2S could lead to the decrease in the pH values of landfill covers; especially, in the LCS with low pH buffer capacity, the pH value of the bottom layer dropped to below 4. Pyrosequencing of 16S ribosomal RNA (rRNA) gene showed that the known sulfur-metabolizing bacteria Ochrobactrum, Paracoccus, Comamonas, Pseudomonas, and Acinetobacter dominated in the WBS and LCS. Among them, Comamonas and Acinetobacter might play an important role in the metabolism of H2S in the WBS. These findings are helpful to understand sulfur bioconversion process in landfill covers and to develop techniques for controlling odor pollution at landfills.

Physical and chemical characterization of actinides in soil from Johnston Atoll

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

Wolf, S.F.; Bates, J.K.; Buck, E.C.

1997-02-01

Characterization of the actinide content of a sample of contaminated coral soil from Johnston Atoll, the site of three non-nuclear destructs of nuclear warhead-carrying THOR missiles in 1962, revealed that >99% of the total actinide content is associated with discrete bomb fragments. After removal of these fragments, there was an inverse correlation between actinide content and soil particle size in particles from 43 to 0.4 {mu}m diameter. Detailed analyses of this remaining soil revealed no discrete actinide phase in these soil particles, despite measurable actinide content. Observations indicate that exposure to the environment has caused the conversion of relatively insolublemore » actinide oxides to the more soluble actinyl oxides and actinyl carbonate coordinated complexes. This process has led to dissolution of actinides from discrete particles and migration to the surrounding soil surfaces, resulting in a dispersion greater than would be expected by physical transport of discrete particles alone. 26 refs., 4 figs., 1 tab.« less

[Heavy metals and hydrocarbons content in soils of settlements of the Yamal-Nenets autonomous region].

PubMed

Alekseev, I I; Abakumov, E V; Shamilishvili, G A; Lodygin, E D

In August 2015 there were executed investigations on the study of the soils diversity of the Yamal-Nenets Autonomous Okrug. One of the directions of this work got be the study of urban soils of settlements of the Yamal-Nenents Autonomous Okrug. The sectors for the observation were settlement of Harsaim, village Aksarka, city of Salekhard, settlement Harp and city of Labytnangi. About 20 soil samples were collected during the field work. Samples were collected from a depth of 0-5 cm and 5-20 cm. Heavy metals (HM) were detected with the use of X-ray fluorescent analyzer “Spectroscan-MAX”. The HM content values were compared with the corresponding Approxible Permissible Concentrations and Maximum Allowable Concentrations (MAC) adopted in Russia. Hydrocarbons content was determined by gravimetric method. Values of the hydrocarbons content in studied soils were compared with the existing regulations of the Russian Federation. The levels of soil contamination by hydrocarbons were determined. The study of soil samples from different settlements allowed to reveal characteristic features of soil contamination of separate settlements by HM and hydrocarbons and to compare them against each other. The vast majority of samples are characterized by arsenic exceedance of MAC, which should indicate to a high regional background of this element. For a more adequate assessment of the Zc meaning as the value of the total pollution index of soils there were used not only arithmetical average values of the coefficients of the chemical composition concentration (Kc), but also their average geometric values. According to levels of total soil contamination most of soil samples are characterized as non-hazardous (Zc<16). Calculation of soil pollution index showed that the most of soil samples have values less than 1. It characterizes soils as unpolluted. Statistical processing of obtained data in the media of the analytical software interface STATISTICA 10 showed a statistically

Chemical and microbiological characterization of an aged PCB-contaminated soil.

PubMed

Stella, T; Covino, S; Burianová, E; Filipová, A; Křesinová, Z; Voříšková, J; Větrovský, T; Baldrian, P; Cajthaml, T

2015-11-15

This study was aimed at complex characterization of three soil samples (bulk soil, topsoil and rhizosphere soil) from a site historically contaminated with polychlorinated biphenyls (PCB). The bulk soil was the most highly contaminated, with a PCB concentration of 705.95 mg kg(-1), while the rhizosphere soil was the least contaminated (169.36 mg kg(-1)). PCB degradation intermediates, namely chlorobenzoic acids (CBAs), were detected in all the soil samples, suggesting the occurrence of microbial transformation processes over time. The higher content of organic carbon in the topsoil and rhizosphere soil than in the bulk soil could be linked to the reduced bioaccessibility (bioavailability) of these chlorinated pollutants. However, different proportions of the PCB congener contents and different bioaccessibility of the PCB homologues indicate microbial biotransformation of the compounds. The higher content of organic carbon probably also promoted the growth of microorganisms, as revealed by phospholipid fatty acid (PFLA) quantification. Tag-encoded pyrosequencing analysis showed that the bacterial community structure was significantly similar among the three soils and was predominated by Proteobacteria (44-48%) in all cases. Moreover, analysis at lower taxonomic levels pointed to the presence of genera (Sphingomonas, Bulkholderia, Arthrobacter, Bacillus) including members with reported PCB removal abilities. The fungal community was mostly represented by Basidiomycota and Ascomycota, which accounted for >80% of all the sequences detected in the three soils. Fungal taxa with biodegradation potential (Paxillus, Cryptococcus, Phoma, Mortierella) were also found. These results highlight the potential of the indigenous consortia present at the site as a starting point for PCB bioremediation processes. Copyright © 2015 Elsevier B.V. All rights reserved.

Characterization and phylogenetic affiliation of Actinobacteria from tropical soils with potential uses for agro-industrial processes.

PubMed

Dornelas, J C M; Figueiredo, J E F; de Abreu, C S; Lana, U G P; Oliveira, C A; Marriel, I E

2017-08-31

Secondary metabolites produced by Actinobacteria of tropical soils represent a largely understudied source of novel molecules with relevant application in medicine, pharmaceutical and food industries, agriculture, and environmental bioremediation. The present study aimed to characterize sixty-nine Actinobacteria isolated from compost and tropical soils using morphological, biochemical, and molecular methods. All the isolates showed high variation for morphological traits considering the color of pigments of the aerial and vegetative mycelium and spore chain morphology. The enzymatic activity of amylase, cellulase, and lipase was highly variable. The amylase activity was detected in 53 (76.81%) isolates. Eighteen isolates showed enzymatic index (EI) > 4.0, and the isolates ACJ 45 (Streptomyces curacoi) and ACSL 6 (S. hygroscopicus) showed the highest EI values (6.44 and 6.42, respectively). The cellulase activity varied significantly (P ≤ 0.05) among the isolates. Twenty-nine isolates (42.02%) showed high cellulase activity, and the isolates ACJ 48 (S. chiangmaiensis) and ACJ 53 (S. cyslabdanicus) showed the highest EI values (6.56 for both isolates). The lipase activity varied statistically (P ≤ 0.05) with fourteen isolates (20.29%) considered good lipase producers (EI > 2.0). The isolate ACSL 6 (S. hygroscopicus) showed the highest EI value of 2.60. Molecular analysis of partial 16S rRNA gene sequencing revealed the existence of 49 species, being 38 species with only one representative member and 11 species represented by one or more strains. All species belonged to three genera, namely Streptomyces (82.61%), Amycolatopsis (7.25%), and Kitasatospora (10.14%). The present results showed the high biotechnological potential of different Actinobacteria from tropical soils.

Evaluation and characterization of thyroid-disrupting activities in soil samples along the Second Songhua River, China.

PubMed

Kong, Dongdong; Wang, Yafei; Wang, Jinsheng; Teng, Yanguo; Li, Na; Li, Jian

2016-11-01

In this study, a recombinant thyroid receptor (TR) gene yeast assay combined with Monte Carlo simulation were used to evaluate and characterize soil samples collected from Jilin (China) along the Second Songhua River, for their ant/agonist effect on TR. No TR agonistic activity was found in soils, but many soil samples exhibited TR antagonistic activities, and the bioassay-derived amiodarone hydrochloride equivalents, which was calculated based on Monte Carlo simulation, ranged from not detected (N.D.) to 35.5μg/g. Hydrophilic substance fractions were determined to be the contributors to TR antagonistic activity in these soil samples. Our results indicate that the novel calculation method is effective for the quantification and characterization of TR antagonists in soil samples, and these data could provide useful information for future management and remediation efforts for contaminated soils. Copyright © 2016 Elsevier Inc. All rights reserved.

Characterization of adsorption and degradation of diuron in carbonatic and noncarbonatic soils.

PubMed

Kasozi, Gabriel N; Nkedi-Kizza, Peter; Agyin-Birikorang, Sampson; Zimmerman, Andrew R

2010-01-27

The adsorption and degradation of the pesticide diuron in carbonatic and noncarbonatic soils were investigated to better understand the fate and transport of diuron in the environment. Batch adsorption experiments yielded isotherms that were well-described by the linear model. Adsorption coefficients normalized to soil organic carbon content (K(oc)) were lowest for carbonatic soils, averaging 259 +/- 48 (95% CI), 558 +/- 109, 973 +/- 156, and 2090 +/- 1054 for carbonatic soils, Histosols, Oxisols, and Spodosols, respectively. In addition, marl-carbonatic soils had much lower K(oc) values (197 +/- 27) than nonmarl-carbonatic soils. Diuron degradation data fit a first-order reaction kinetics model, yielding half-lives in soils ranging from 40 to 267 days. There was no significant difference between the average diuron degradation rate coefficients of each of the soil groups studied. Given the low adsorption capacity of carbonatic soils, it may be advisable to lower herbicide application rates in agricultural regions with carbonatic soils such as southern Florida to protect aquatic ecosystems and water quality.

Sensitivity of ecological soil-screening levels for metals to exposure model parameterization and toxicity reference values.

PubMed

Sample, Bradley E; Fairbrother, Anne; Kaiser, Ashley; Law, Sheryl; Adams, Bill

2014-10-01

Ecological soil-screening levels (Eco-SSLs) were developed by the United States Environmental Protection Agency (USEPA) for the purposes of setting conservative soil screening values that can be used to eliminate the need for further ecological assessment for specific analytes at a given site. Ecological soil-screening levels for wildlife represent a simplified dietary exposure model solved in terms of soil concentrations to produce exposure equal to a no-observed-adverse-effect toxicity reference value (TRV). Sensitivity analyses were performed for 6 avian and mammalian model species, and 16 metals/metalloids for which Eco-SSLs have been developed. The relative influence of model parameters was expressed as the absolute value of the range of variation observed in the resulting soil concentration when exposure is equal to the TRV. Rank analysis of variance was used to identify parameters with greatest influence on model output. For both birds and mammals, soil ingestion displayed the broadest overall range (variability), although TRVs consistently had the greatest influence on calculated soil concentrations; bioavailability in food was consistently the least influential parameter, although an important site-specific variable. Relative importance of parameters differed by trophic group. Soil ingestion ranked 2nd for carnivores and herbivores, but was 4th for invertivores. Different patterns were exhibited, depending on which parameter, trophic group, and analyte combination was considered. The approach for TRV selection was also examined in detail, with Cu as the representative analyte. The underlying assumption that generic body-weight-normalized TRVs can be used to derive protective levels for any species is not supported by the data. Whereas the use of site-, species-, and analyte-specific exposure parameters is recommended to reduce variation in exposure estimates (soil protection level), improvement of TRVs is more problematic. © 2014 The Authors

Sensitivity of ecological soil-screening levels for metals to exposure model parameterization and toxicity reference values

PubMed Central

Sample, Bradley E; Fairbrother, Anne; Kaiser, Ashley; Law, Sheryl; Adams, Bill

2014-01-01

Ecological soil-screening levels (Eco-SSLs) were developed by the United States Environmental Protection Agency (USEPA) for the purposes of setting conservative soil screening values that can be used to eliminate the need for further ecological assessment for specific analytes at a given site. Ecological soil-screening levels for wildlife represent a simplified dietary exposure model solved in terms of soil concentrations to produce exposure equal to a no-observed-adverse-effect toxicity reference value (TRV). Sensitivity analyses were performed for 6 avian and mammalian model species, and 16 metals/metalloids for which Eco-SSLs have been developed. The relative influence of model parameters was expressed as the absolute value of the range of variation observed in the resulting soil concentration when exposure is equal to the TRV. Rank analysis of variance was used to identify parameters with greatest influence on model output. For both birds and mammals, soil ingestion displayed the broadest overall range (variability), although TRVs consistently had the greatest influence on calculated soil concentrations; bioavailability in food was consistently the least influential parameter, although an important site-specific variable. Relative importance of parameters differed by trophic group. Soil ingestion ranked 2nd for carnivores and herbivores, but was 4th for invertivores. Different patterns were exhibited, depending on which parameter, trophic group, and analyte combination was considered. The approach for TRV selection was also examined in detail, with Cu as the representative analyte. The underlying assumption that generic body-weight–normalized TRVs can be used to derive protective levels for any species is not supported by the data. Whereas the use of site-, species-, and analyte-specific exposure parameters is recommended to reduce variation in exposure estimates (soil protection level), improvement of TRVs is more problematic. Environ Toxicol Chem 2014

Iron-bound organic carbon in forest soils: quantification and characterization

DOE PAGES

Zhao, Qian; Poulson, Simon R.; Obrist, Daniel; ...

2016-08-24

Iron oxide minerals play an important role in stabilizing organic carbon (OC) and regulating the biogeochemical cycles of OC on the earth surface. To predict the fate of OC, it is essential to understand the amount, spatial variability, and characteristics of Fe-bound OC in natural soils. In this study, we investigated the concentrations and characteristics of Fe-bound OC in soils collected from 14 forests in the United States and determined the impact of ecogeographical variables and soil physicochemical properties on the association of OC and Fe minerals. On average, Fe-bound OC contributed 37.8 % of total OC (TOC) in forestmore » soils. Atomic ratios of OC : Fe ranged from 0.56 to 17.7, with values of 1–10 for most samples, and the ratios indicate the importance of both sorptive and incorporative interactions. The fraction of Fe-bound OC in TOC (fFe-OC) was not related to the concentration of reactive Fe, which suggests that the importance of association with Fe in OC accumulation was not governed by the concentration of reactive Fe. Concentrations of Fe-bound OC and fFe-OC increased with latitude and reached peak values at a site with a mean annual temperature of 6.6 °C. Attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR) and near-edge X-ray absorption fine structure (NEXAFS) analyses revealed that Fe-bound OC was less aliphatic than non-Fe-bound OC. Fe-bound OC also was more enriched in 13C compared to the non-Fe-bound OC, but C/N ratios did not differ substantially. In summary, 13C-enriched OC with less aliphatic carbon and more carboxylic carbon was associated with Fe minerals in the soils, with values of fFe-OC being controlled by both sorptive and incorporative associations between Fe and OC. Overall, this study demonstrates that Fe oxides play an important role in regulating the biogeochemical cycles of C in forest soils and uncovers the governing factors for the spatial variability and characteristics of Fe-bound OC.« less

Comparative characterization of sewage sludge compost and soil: Heavy metal leaching characteristics.

PubMed

Fang, Wen; Wei, Yonghong; Liu, Jianguo

2016-06-05

The leaching and accumulation of heavy metals are major concerns following the land application of sewage sludge compost (SSC). We comparatively characterized SSC, the reference soil, and the SSC amended soil to investigate their similarities and differences regarding heavy metal leaching behavior and then to evaluate the effect of SSC land application on the leaching behavior of soil. Results showed that organic matter, including both of particulate organic matter (POM) and dissolved organic matter (DOM), were critical factors influencing heavy metal leaching from both of SSC and the soil. When SSC was applied to soil at the application rate of 48t/ha, the increase of DOM content slightly enhanced heavy metal leaching from the amended soil over the applicable pH domain (6soil and the amended soil. Copyright © 2016 Elsevier B.V. All rights reserved.

Characterization of soil nematode communities in three cropping systems through morphological and DNA metabarcoding approaches

USDA-ARS?s Scientific Manuscript database

Communities of soil nematodes impact ecosystem functions, including plant growth, decomposition, and nutrient cycling, all of which are vital processes in agriculture. We used complementary morphological and DNA metabarcoding analyses to characterize soil nematode communities in three cropping syste...

Soil erosion and deposition before and after fire in oak savannas

Treesearch

Peter F. Ffolliott; Gerald J. Gottfried; Hui Chen; Aaron T. Kauffman; Cody L. Stropki; Daniel G. Neary

2013-01-01

Effects of low severity prescribed burning treatments and a wildfire on soil erosion and deposition in the oak savannas in the Southwestern Borderlands are reported. Measurements in the spring and fall, respectively, characterize soil movements following winter rains and high-intensity summer rainstorms. Annual values are also presented. Relationships between soil...

Site and soil characterization of hazardous waste sites using an expert system guide

NASA Astrophysics Data System (ADS)

Cameron, Roy E.

1993-03-01

An expert system guide (knowledge book) has been devised to assist field personnel who must identify, describe, sample, and interpret size and soil characteristics of hazardous waste sites. The guide takes an approach that will be unfamiliar to most soil and environmental scientists and is directed to on-scene coordinators and project managers and others who may have little soil science training. It meets the need of the U.S. Environmental Protection Agency for standard procedures, guidelines, or protocols that address soil and site contamination, particularly heavy metals. The guide is organized to include: (1) general considerations and processes for collecting and using site and soils data, (2) detailed knowledge frames (descriptive profiles) of likely site and soil conditions, (3) a citation of references, (4) an appendix listing common sources of characterization data, and (5) a glossary of more than 900 general definitions.

Review of State Soil Cleanup Levels for Dioxin (December 2009)

EPA Science Inventory

This final report summarizes a survey of state soil cleanup levels for dioxin and characterizes the science underlying these values. The objective of this project was to summarize existing state cleanup levels for dioxin in soil, together with their scientific bases where availa...

Physicochemical Characterization of Potential Mobile Organic Matter In Five Typical German Agricultural Soils

NASA Astrophysics Data System (ADS)

Séquaris, J.-M.; Lewandowski, H.; Vereecken, H.

Organic matter (OM) in soils plays an important role, i.e., in maintaining soil structure or as source of nutrients. OM is mainly adsorbed at the surface of clay minerals and oxides and remains mostly immobile. However, mobile OM in dissolved form (DOM) or associated with water dispersible colloids (WDC) in soil water may influence trans- port of pollutants. The goal of this study is to compare 5 typical German agricultural soils in terms of distribution and quality of OM in the top soil (0-15 cm). The present report focuses on the physicochemical characterization of potential mobile OM so- lutions obtained after physical fractionation of soil materials based on sedimentation after a prolonged shaking in water or electrolyte solutions. Three soil fractions dif- fering in particle size were separated in function of sedimentation time: a colloidal fraction: < 2 ţm; a microaggregate fraction: 2-20 ţm and a sediment fraction: > 20 ţm. The soil electrolyte phase containing the DOM fraction was obtained by a high-speed centrifugation of the colloidal phase. After a water or low electrolyte concentration (« 1 mM Ca2+) extraction, it can be shown that the mobile fraction of OM or OC (organic carbon) is distributed between the colloidal and the electrolyte phases in a concentration ratio range of 10-40 to 1. A less mobile OC fraction is associated with the microaggregate fraction while immobile OC remains adsorbed in the sediment fraction. An increasing OC and total-N content with diminishing particle-size of soil (colloidal and microaggregate fractions) has been confirmed. A higher OC input due to special soil management is sensitively detected in fractions with a greater particle size (sediment fraction). Increasing the Ca2+ concentration up to 10 mM during the water extraction diminishes the DOC concentration by an average factor of 3 while the OC associated with the dispersed colloids (OCWDC) vanished almost completely. Thus, a critical coagulation concentration of

Characterization of Cultures Enriched from Acidic Polycyclic Aromatic Hydrocarbon-Contaminated Soil for Growth on Pyrene at Low pH▿

PubMed Central

Uyttebroek, Maarten; Vermeir, Steven; Wattiau, Pierre; Ryngaert, Annemie; Springael, Dirk

2007-01-01

Two polycyclic aromatic hydrocarbon (PAH)-contaminated soils of pH 2 were successfully used as inoculum to enrich cultures growing on phenanthrene and pyrene at different pHs, including pH 3. Selected pyrene-utilizing cultures obtained at pH 3, pH 5, and pH 7 were further characterized. All showed rapid [14C]pyrene mineralization at pH 3 and pH 5 and grew on pyrene at pH values ranging from 2 to 6. Eubacterial and mycobacterial 16S rRNA gene denaturing gradient gel electrophoresis fingerprinting and sequencing indicated that the cultures were dominated by a single bacterium closely related to Mycobacterium montefiorense, belonging to the slow-growing Mycobacterium sp. In contrast, a culture enriched on pyrene at pH 7 from a slightly alkaline soil sampled at the same site was dominated by Pseudomonas putida and a fast-growing Mycobacterium sp. The M. montefiorense-related species dominating the pyrene-utilizing cultures enriched from the acidic soils was also the dominant Mycobacterium species in the acidic soils. Our data indicate that a slow-growing Mycobacterium species is involved in PAH degradation in that culture and show that bacteria able to degrade high-molecular-weight PAHs at low pH are present in acidic PAH-contaminated soil. PMID:17369339

Petrographic characterization of lunar soils: Application of x ray digital-imaging to quantitative and automated analysis

NASA Technical Reports Server (NTRS)

Higgins, Stefan J.; Patchen, Allan; Chambers, John G.; Taylor, Lawrence A.; Mckay, David S.

1994-01-01

The rocks and soils of the moon will be the raw materials for various engineering needs at a lunar base, such as sources of hydrogen, oxygen, metals, etc. The material of choice for most of the bulk needs is the regolith and its less than 1 cm fraction, the soil. For specific mineral resources it may be necessary to concentrate minerals from either rocks or soils. Therefore, quantitative characterizations of these rocks and soils are necessary in order to better define their mineral resource potential. However, using standard point-counting microscopic procedures, it is difficult to quantitatively determine mineral abundances and virtually impossible to obtain data on mineral distributions within grains. As a start to fulfilling these needs, Taylor et al. and Chambers et al. have developed a procedure for characterization of crushed lunar rocks using x ray digital imaging. The development of a similar digital imaging procedure for lunar soils as obtained from a spectrometer is described.

Assessment of existing roadside swales with engineered filter soil: I. Characterization and lifetime expectancy.

PubMed

Ingvertsen, Simon T; Cederkvist, Karin; Régent, Yoann; Sommer, Harald; Magid, Jakob; Jensen, Marina B

2012-01-01

Roadside infiltration swales with well-defined soil mixtures (filter soil) for the enhancement of both infiltration and treatment of stormwater runoff from roads and parking areas have been common practice in Germany for approximately two decades. Although the systems have proven hydraulically effective, their treatment efficiency and thus lifetime expectancies are not sufficiently documented. The lack of documentation restricts the implementation of new such systems in Germany as well as other countries. This study provides an assessment of eight roadside infiltration swales with filter soil from different locations in Germany that have been operational for 6 to16 yr. The swales were assessed with respect to visual appearance, infiltration rate, soil pH, and soil texture, as well as soil concentration of organic matter, heavy metals (Cd, Cr, Cu, Pb, Zn), and phosphorus. Visually, the swales appeared highly variable with respect to soil color and textural layering as well as composition of plants and soil-dwelling organisms. Three swales still comply with the German design criteria for infiltration rate (10 m/s), while the remaining swales have lower, yet acceptable, infiltration rates around 10 m/s. Six of the eight studied soils have heavy metal concentrations exceeding the limit value for unpolluted soil. Provided that the systems are able to continuously retain existing and incoming pollutants, our analysis indicates that the soils can remain operational for another 13 to 136 yr if the German limit values for unrestricted usage in open construction works are applied. However, no official guidelines exist for acceptable soil quality in existing infiltration facilities. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Tree Sampling as a Method to Assess Vapor Intrusion Potential at a Site Characterized by VOC-Contaminated Groundwater and Soil.

PubMed

Wilson, Jordan L; Limmer, Matthew A; Samaranayake, V A; Schumacher, John G; Burken, Joel G

2017-09-19

Vapor intrusion (VI) by volatile organic compounds (VOCs) in the built environment presents a threat to human health. Traditional VI assessments are often time-, cost-, and labor-intensive; whereas traditional subsurface methods sample a relatively small volume in the subsurface and are difficult to collect within and near structures. Trees could provide a similar subsurface sample where roots act as the "sampler' and are already onsite. Regression models were developed to assess the relation between PCE concentrations in over 500 tree-core samples with PCE concentrations in over 50 groundwater and 1000 soil samples collected from a tetrachloroethylene- (PCE-) contaminated Superfund site and analyzed using gas chromatography. Results indicate that in planta concentrations are significantly and positively related to PCE concentrations in groundwater samples collected at depths less than 20 m (adjusted R 2 values greater than 0.80) and in soil samples (adjusted R 2 values greater than 0.90). Results indicate that a 30 cm diameter tree characterizes soil concentrations at depths less than 6 m over an area of 700-1600 m 2 , the volume of a typical basement. These findings indicate that tree sampling may be an appropriate method to detect contamination at shallow depths at sites with VI.

Tree sampling as a method to assess vapor intrusion potential at a site characterized by VOC-contaminated groundwater and soil

USGS Publications Warehouse

Wilson, Jordan L.; Limmer, Matthew A.; Samaranayake, V. A.; Schumacher, John G.; Burken, Joel G.

2017-01-01

Vapor intrusion (VI) by volatile organic compounds (VOCs) in the built environment presents a threat to human health. Traditional VI assessments are often time-, cost-, and labor-intensive; whereas traditional subsurface methods sample a relatively small volume in the subsurface and are difficult to collect within and near structures. Trees could provide a similar subsurface sample where roots act as the “sampler’ and are already onsite. Regression models were developed to assess the relation between PCE concentrations in over 500 tree-core samples with PCE concentrations in over 50 groundwater and 1000 soil samples collected from a tetrachloroethylene- (PCE-) contaminated Superfund site and analyzed using gas chromatography. Results indicate that in planta concentrations are significantly and positively related to PCE concentrations in groundwater samples collected at depths less than 20 m (adjusted R2 values greater than 0.80) and in soil samples (adjusted R2 values greater than 0.90). Results indicate that a 30 cm diameter tree characterizes soil concentrations at depths less than 6 m over an area of 700–1600 m2, the volume of a typical basement. These findings indicate that tree sampling may be an appropriate method to detect contamination at shallow depths at sites with VI.

Characterizing regional soil mineral composition using spectroscopyand geostatistics

USGS Publications Warehouse

Mulder, V.L.; de Bruin, S.; Weyermann, J.; Kokaly, Raymond F.; Schaepman, M.E.

2013-01-01

This work aims at improving the mapping of major mineral variability at regional scale using scale-dependent spatial variability observed in remote sensing data. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data and statistical methods were combined with laboratory-based mineral characterization of field samples to create maps of the distributions of clay, mica and carbonate minerals and their abundances. The Material Identification and Characterization Algorithm (MICA) was used to identify the spectrally-dominant minerals in field samples; these results were combined with ASTER data using multinomial logistic regression to map mineral distributions. X-ray diffraction (XRD)was used to quantify mineral composition in field samples. XRD results were combined with ASTER data using multiple linear regression to map mineral abundances. We testedwhether smoothing of the ASTER data to match the scale of variability of the target sample would improve model correlations. Smoothing was donewith Fixed Rank Kriging (FRK) to represent the mediumand long-range spatial variability in the ASTER data. Stronger correlations resulted using the smoothed data compared to results obtained with the original data. Highest model accuracies came from using both medium and long-range scaled ASTER data as input to the statistical models. High correlation coefficients were obtained for the abundances of calcite and mica (R2 = 0.71 and 0.70, respectively). Moderately-high correlation coefficients were found for smectite and kaolinite (R2 = 0.57 and 0.45, respectively). Maps of mineral distributions, obtained by relating ASTER data to MICA analysis of field samples, were found to characterize major soil mineral variability (overall accuracies for mica, smectite and kaolinite were 76%, 89% and 86% respectively). The results of this study suggest that the distributions of minerals and their abundances derived using FRK-smoothed ASTER data more closely match the spatial

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.

Nutrient Characterization of Rainwater, Soil and Groundwater from Two Different Watersheds, Lake Taihu, China

NASA Astrophysics Data System (ADS)

Thaw, M.; Gao, F.; Yu, Z.; Acharya, K.

2012-12-01

Over the past two decades, an increase of nutrients to Lake Taihu, China has resulted in hyper-eutrophication and the production of severe cyanobacterial blooms. While many past studies have focused on how surface water transports nutrients to the lake, this study seeks to characterize the concentration of nutrients in different media, including rainwater, soil and groundwater from two different watersheds. These two watersheds varied in overall land use, and agricultural sites within each watershed varied by crop type and growing method. Samples were collected from the Meilin watershed, a mix of forest and agricultural land and the Zhangjiagang watershed, which consisted of industrial, urban and agricultural lands. Samples included soils, groundwater and rain water. Soils from each site were characterized by aggregate size class and analyzed for total nitrogen and total phosphorus. Rainwater and groundwater samples were analyzed for total nitrogen and total phosphorus.

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.

Maps of averaged spectral deviations from soil lines and their comparison with traditional soil maps

NASA Astrophysics Data System (ADS)

Rukhovich, D. I.; Rukhovich, A. D.; Rukhovich, D. D.; Simakova, M. S.; Kulyanitsa, A. L.; Bryzzhev, A. V.; Koroleva, P. V.

2016-07-01

The analysis of 34 cloudless fragments of Landsat 5, 7, and 8 images (1985-2014) on the territory of Plavsk, Arsen'evsk, and Chern districts of Tula oblast has been performed. It is shown that bare soil surface on the RED-NIR plots derived from the images cannot be described in the form of a sector of spectral plane as it can be done for the NDVI values. The notion of spectral neighborhood of soil line (SNSL) is suggested. It is defined as the sum of points of the RED-NIR spectral space, which are characterized by spectral characteristics of the bare soil applied for constructing soil lines. The way of the SNSL separation along the line of the lowest concentration density of points on the RED-NIR spectral space is suggested. This line separates bare soil surface from vegetating plants. The SNSL has been applied to construct soil line (SL) for each of the 34 images and to delineate bare soil surface on them. Distances from the points with averaged RED-NIR coordinates to the SL have been calculated using the method of moving window. These distances can be referred to as averaged spectral deviations (ASDs). The calculations have been performed strictly for the SNSL areas. As a result, 34 maps of ASDs have been created. These maps contain ASD values for 6036 points of a grid used in the study. Then, the integral map of normalized ASD values has been built with due account for the number of points participating in the calculation (i.e., lying in the SNSL) within the moving window. The integral map of ASD values has been compared with four traditional soil maps on the studied territory. It is shown that this integral map can be interpreted in terms of soil taxa: the areas of seven soil subtypes (soddy moderately podzolic, soddy slightly podzolic, light gray forest. gray forest, dark gray forest, podzolized chernozems, and leached chernozems) belonging to three soil types (soddy-podzolic, gray forest, and chernozemic soils) can be delineated on it.

[Effects of different soil types on the foliar δ13C values of common local plant species in karst rocky desertification area in central Guizhou Province].

PubMed

Du, Xue-lian; Wang, Shi-jie; Luo, Xu-qiang

2014-09-01

By measuring the foliar δ13C values of common local plant species grown in different soil types in Wangjiazhai catchments, a typical karst desertification area in Qingzhen City, Central Guizhou, we studied the impact of soil type and rocky desertification grade on the foliar δ13C values. The results showed that the foliar δ13C values were more negative in yellow soil area than those in black calcareous area and there was no obvious difference in foliar δ13C values between these two soil types. The distribution interval of foliar δ13C values in yellow soil area was narrower than those in black calcareous area and the variation coefficient of foliar δ13C values in yellow soil area were smaller than those in black calcareous area. With increasing degree of karst rocky desertification, the foliar δ13C values of plant community in black calcareous area increased, whereas those in yellow soil area first increased and then decreased. The result of multiple comparison showed that the difference in foliar δ13C values of plant community among rocky desertification grade was not obvious in yellow soil area, but it was obvious in black calcareous area. Correlation analysis between the foliar δ13C values of plant species and the main environmental factors indicated that slope and soil thickness were the main factors which affected the foliar δ13C values of plants in yellow soil area and soil water contant was the main factor in black calcareous area. The impact of soil on the foliar δ13C values was realized by adjusting the soil moisture in study area.

Characterizing Zinc Speciation in Soils from a Smelter-Affected Boreal Forest Ecosystem.

PubMed

Hamilton, Jordan G; Farrell, Richard E; Chen, Ning; Feng, Renfei; Reid, Joel; Peak, Derek

2016-03-01

HudBay Minerals, Inc., has mined and/or processed Zn and Cu ore in Flin Flon, MB, Canada, since the 1930s. The boreal forest ecosystem and soil surrounding these facilities have been severely impacted by mixed metal contamination and HSO deposition. Zinc is one of the most prevalent smelter-derived contaminants and has been identified as a key factor that may be limiting revegetation. Metal toxicity is related to both total concentrations and speciation; therefore, X-ray absorption spectroscopy and X-ray fluorescence mapping were used to characterize Zn speciation in soils throughout the most heavily contaminated areas of the landscape. Zinc speciation was linked to two distinct soil types. Group I soils consist of exposed soils in weathered positions of bedrock outcrops with Zn present primarily as franklinite, a (ZnFeO) spinel mineral. Group II soils are stabilized by an invasive metal-tolerant grass species, with Zn found as a mixture of octahedral (Fe oxides) and tetrahedral Mn oxides) adsorption complexes with a franklinite component. Soil erosion influences Zn speciation through the redistribution of Zn and soil particulates from Group I landscape positions to Group II soils. Despite Group II soils having the highest concentrations of CaCl-extractable Zn, they support metal-tolerant plant growth. The metal-tolerant plants are probably preferentially colonizing these areas due to better soil and nutrient conditions as a result of soil deposition from upslope Group I areas. Zinc concentration and speciation appears to not influence the colonization by metal-tolerant grasses, but the overall soil properties and erosion effects prevent the revegetation by native boreal forest species. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Integrated use of soil physical and water isotope methods for ecohydrological characterization of desertified areas

NASA Astrophysics Data System (ADS)

Külls, Christoph; Nunes, Alice; Köbel-Batista, Melanie; Branquinho, Cristina; Bianconi, Nadja; Costantini, Eduardo

2014-05-01

Measures for monitoring desertification and soil degradation require a thorough understanding of soil physical properties and of the water balance in order to guide restoration efforts (Costantini et al. 2009). It is hypothesized that long term restoration success on degraded land depends on a series of interacting factors such as exposition, soil type, soil hydrology including lateral flow on hill-slope catenae. Recently, new soil water isotope measurement techniques have been developed (Garvelmann et al. 2012) that provide much faster and reliable stable water isotope profiles in soils. This technique yield information on groundwater recharge, soil water balance and on the origin of water available for plants, which in combination with conservative chemical tracers (chloride) can be validated. A multidisciplinary study including ecologists, soil physicists and hydrologists of the COST Action Desert Restoration Hub was carried out on four semi-arid sites in Portugal. A comparative characterization of soil physical parameters, soil water isotope and chloride profiles was performed in order to estimate pedoclimate, soil aridity, soil water balance and groundwater recharge. In combination with soil physical data a comprehensive and cross-validated characterization of pedoclimate and soil aridity was obtained. These indicators were then integrated and related to plant cover. The long-term rainfall of the four sites ranges from 512 to 638 mm, whereas air temperature is from 15.8 to 17.0°C. The De Martonne index of aridity spans from 19.3 to 24.6, pointing to semiarid to moderately arid climatic conditions. The long-term average number of days when the first 0.50 m of soil is dry ranges from 110 to 134, while the mean annual soil temperature at 0.50 m spans from 15.8 and 19.1°C. The studied profiles show different hydrological characteristics, in particular, the estimated hydraulic conductivity ranges from 0.1-1 to 10-100 µm/s. Three out of four profiles show a

Characteristics and nutrient values of biochars produced from giant reed at different temperatures

USDA-ARS?s Scientific Manuscript database

Application of biochars to soils is suggested as an effective way for improving soil quality. To investigate the effect of pyrolysis temperature on properties and nutrients value, biochars were produced from giant reed [Arundo donax L.] at 300-600 degrees Celsius and characterized for their physical...

Timber Harvesting Effects on Spatial Variability of Southeastern U.S. Piedmont Soil Properties

Treesearch

J.N. Shaw; Emily A. Carter

2002-01-01

Site-specific forestry requires detailed characterization of the spatial distribution of forest soil properties and the magnitude of harvesting impacts in order to prescribe appropriate management schemes. Furthermore, evaluation of the effects of timber harvesting on soil properties conducted on a landscape scale improves the interpretive value of soil survey data....

Adding Value to Ash and Digestate (AVAnD): Performance of Novel Soil Amendents on the Soil-Plant System Under Glasshouse Conditions

NASA Astrophysics Data System (ADS)

Lag-Brotons, Alfonso; Marshall, Rachel; Herbert, Ben; Hurst, Lois; Ostle, Nick; Dodd, Ian; Quinton, John; Surridge, Ben; Aiouache, Farid; Semple, Kirk T.

2017-04-01

Resource recovery from waste plays a central role in strategies tackling current worldwide sustainability problems. In this sense, two waste streams derived from bioenergy production (anaerobic digestion and incineration), digestate [D] and biomass ash [A], may be especially valuable within agriculture. These materials offer complementary plant nutrient profiles for alternative fertiliser production (i.e. nitrogen [N] from D and phosphorus [P] from A). In addition, incorporating these materials into the soil could impact upon several soil/plant characteristics, and have positive effects on ecosystem services (eg. nutrient cycling). Therefore, this present work assessed the effects of A/D blends on the soil-plant system under controlled conditions (glasshouse). The overarching aim of "Adding Value to Ash and Digestate [AVAnD]" project is to identify novel nutrient-recycling pathways to maximise soil quality and crop productivity utilising waste streams derived from bioenergy production. Two pot experiments of 6 weeks duration were carried out [Exp. A and Exp. B] using contrasting agricultural soils (neutral loam and sandy acidic soil) and wheat as the crop. A factorial randomised block design was selected, with fertilisation treatment and soil condition (planted/unplanted) as factors. Fertilisation treatments (n=13) were applied at a rate of 63/60 kg N/P2O5 per ha and comprised: control ([C], no fertilisation), urea [U], urea+superphosphate [U+P], fly ash [A1], bottom ash [A2], U+A1; U+A2, anaerobic digestates [D1, D2] and ash/digestate blends [D1A1, D1A2, D2A1, D2A2]. Each block (n=5) contained 8 planted and 5 unplanted pots (104 planted + 65 unplanted experimental units). At the end of the experiment, all the plants were assessed for morphometric traits, while for tissue elemental analyses the total number of replicates per treatment was randomly reduced (n=5/treatment). Soil physico-chemical properties (i.e. available nitrogen, pH) were assessed in unplanted and

[Heavy Metals Accmultio in the Caofeidian Reclamation Soils: Indicated by Soil Magnetic Susceptibility].

PubMed

Xue, Yong; Zhou, Qian; Li, Yuan; Zhang, Hai-bo; Hu, Xue-feng; Luo, Yong-ming

2016-04-15

The environmental magnetism method has been widely applied to identify soil heavy metal pollution, which is characterized by simplicity, efficiency, non-destructivity and sensitivity. The present study used magnetic susceptibility to assess the accumulation of heavy metals in soils of the Caofeidian industrial zone which is a typical reclamation area in northern China. The study area was divided into three sub-zones based on the function, including industrial zone, living zone, natural tidal flat and wetland. A total of 35 topsoil samples (0-10 cm) and 3 soil profiles were collected from the three sub-zones. Magnetic susceptibility (X(lf)), iron oxide (Fe2O3) contents and heavy metals contents (Cr, Ni, Cu, Zn, As, Pb, Mn and V) of the samples were analyzed. The results showed that X(lf) values and heavy metals contents exhibited higher spatial variability in the top soil of the industrial zone, indicating the severe impacts of industrial activities. In the soil profiles of the industrial and living zones, all heavy metals were enriched to different degrees in the upper layer (0-20 cm). However, there was no significant change of heavy metal contents in the soil profiles of tidal flat which was far from the industrial area. The X(lf) value was significantly (P < 0.01) positively correlated with the contents of Fe2O3, Ni, Cu, As and V in the industrial top soil. This indicated that X(lf) could be used as an indicator for heavy metal accumulation in the industrial zone. However, the X(lf) value was not suitable to be an indicator to show the heavy metal accumulation in the soils of living zone and natural tidal flat. This might be associated with the different sources of magnetic materials among the different sub-zones and the special characteristics of the soils in the tidal flat and wetland.

Background concentrations and reference values for heavy metals in soils of Cuba.

PubMed

Alfaro, Mirelys Rodríguez; Montero, Alfredo; Ugarte, Olegario Muñiz; do Nascimento, Clístenes Williams Araújo; de Aguiar Accioly, Adriana Maria; Biondi, Caroline Miranda; da Silva, Ygor Jacques Agra Bezerra

2015-01-01

The potential threat of heavy metals to human health has led to many studies on permissible levels of these elements in soils. The objective of this study was to establish quality reference values (QRVs) for Cd, Pb, Zn, Cu, Ni, Cr, Fe, Mn, As, Hg, V, Ba, Sb, Ag, Co, and Mo in soils of Cuba. Geochemical associations between trace elements and Fe were also studied, aiming to provide an index for establishing background concentrations of metals in soils. Surface samples of 33 soil profiles from areas of native forest or minimal anthropic influence were collected. Samples were digested (USEPA method 3051A), and the metals were determined by ICP-OES. The natural concentrations of metals in soils of Cuba followed the order Fe > Mn > Ni > Cr > Ba > V > Zn > Cu > Pb > Co > As > Sb > Ag > Cd > Mo > Hg. The QRVs found for Cuban soils were as follows (mg kg(-1)): Ag (1), Ba (111), Cd (0.6), Co (25), Cr (153), Cu (83), Fe (54,055), Mn (1947), Ni (170), Pb (50), Sb (6), V (137), Zn (86), Mo (0.1), As (19), and Hg (0.1). The average natural levels of heavy metals are above the global average, especially for Ni and Cr. The chemical fractionation of soil samples presenting anomalous concentrations of metals showed that Cu, Ni, Cr, Sb, and As have low bioavailability. This suggests that the risk of contamination of agricultural products via plant uptake is low. However, the final decision on the establishment of soil QRVs in Cuba depends on political, economic, and social issues and in-depth risk analyses considering all routes of exposure to these elements.

Estimation of soil-soil solution distribution coefficient of radiostrontium using soil properties.

PubMed

Ishikawa, Nao K; Uchida, Shigeo; Tagami, Keiko

2009-02-01

We propose a new approach for estimation of soil-soil solution distribution coefficient (K(d)) of radiostrontium using some selected soil properties. We used 142 Japanese agricultural soil samples (35 Andosol, 25 Cambisol, 77 Fluvisol, and 5 others) for which Sr-K(d) values had been determined by a batch sorption test and listed in our database. Spearman's rank correlation test was carried out to investigate correlations between Sr-K(d) values and soil properties. Electrical conductivity and water soluble Ca had good correlations with Sr-K(d) values for all soil groups. Then, we found a high correlation between the ratio of exchangeable Ca to Ca concentration in water soluble fraction and Sr-K(d) values with correlation coefficient R=0.72. This pointed us toward a relatively easy way to estimate Sr-K(d) values.

Following The Money: Characterizing the Dynamics of Microbial Ecosystems and Labile Organic Matter in Grassland Soils

NASA Astrophysics Data System (ADS)

Herbert, B. E.; McNeal, K. S.

2006-12-01

The dynamics of soil microbial ecosystems and labile fractions of soil organic matter in grasslands have important implications for the response of these critical ecosystems to perturbations. Organic, inorganic and genetic biomarkers in the solid (e.g. lipids, microbial DNA), liquid (e.g. porewater ions) or gaseous phases (e.g. carbon dioxide) have been used to characterize carbon cycling and soil microbial ecology. These proxies are generally limited in the amount of temporal information that they can provide (i.e., solid-phase proxies) or the amount of specific information they can provide about carbon sources or microbial community processes (e.g. inorganic gases). It is the aim of this research to validate the use of soil volatile organic carbon emissions (VOCs) as useful indicators of subsurface microbial community shifts and processes as a function of ecosystem perturbations. We present results of method validation using laboratory microcosm, where VOC metabolites as characterized by gas chromatography and mass spectrometry (GC-MS), were related to other proxies including carbon dioxide (CO2) via infra-red technology, and microbial community shifts as measured by Biolog© and fatty acid methyl ester (FAME) techniques. Experiments with soil collected from grasslands along the coastal margin region in southern Texas were preformed where environmental factors such as soil water content, soil type, and charcoal content are manipulated. Results indicate that over fifty identifiable VOC metabolites are produced from the soils, where many (~15) can be direct indicators of microbial ecology. Principle component analysis (PCA) evidences these trends through similar cluster patterns for the VOC results, the Biolog© results, and FAME. Regression analysis further shows that VOCs are significant (p < 0.05) indicators of microbial stress. Our results are encouraging that characterizing VOCs production in grassland soils are easy to measure, relatively inexpensive method

Magnetic Measurements of Atmospheric Dust Deposition in Soils

NASA Astrophysics Data System (ADS)

Kapička, Aleš; Petrovský, Eduard; Grison, Hana; Podrázský, Vilém; Křížek, Pavel

2010-05-01

Atmospheric dust of anthropogenic origin contains significant portion of minerals characterized by ferrimagnetic properties [1,2]. These minerals, mostly iron oxides, can serve as tracers of industrial pollutants in soil layers. Moreover, recent results, e.g., [3,4] show significant correlation between concentration-dependent magnetic parameters (e.g., low-field magnetic susceptibility) and concentration of heavy metals (e.g., Pb, Zn, Cd). In our paper we have investigated magnetic properties of depth soil profiles from Krušné hory Mountains (Czech Republic), which belong to a highly contaminated, so-called Black Triangle in central Europe. Emissions are determined by considerable concentration of big sources of pollution (power plants burning fossil fuel, metallurgical and chemical industry). Increased values of magnetic susceptibility (25 - 200 × 10-5 SI) were clearly identified in the top-soil layers. Thermomagnetic analyses and SEM observation indicate that the accumulated anthropogenic ferrimagnetics dominate these layers. Magnetic enhancement is limited to depths of 4-7 cm below the soil surface, usually in F-H or top of Ah soil horizons; deeper soil horizons contain mainly magnetically weak materials and are characterized by much lower values of susceptibility (up to 30 × 10-5 SI). Significant magnetic parameters (e.g., Curie temperature Tc) and SEM results of contaminated topsoils are comparable with magnetic parameters of atmospheric dust, collected (using high-volume samplers) at the same localities.

Nickel, Cobalt, Chromium and Copper in agricultural and grazing land soils of Europe

NASA Astrophysics Data System (ADS)

Albanese, Stefano; Sadeghi, Martiya; De Vivo, Benedetto; Lima, Annamaria; Cicchella, Domenico; Dinelli, Enrico

2014-05-01

In the framework of the GEMAS (Geochemical Mapping of Agricultural and Grazing Land Soils) project, concentrations of Ni, Co, Cu and Cr were determined for the whole available dataset (2218 samples of agricultural soil and 2127 samples of grazing land soil) covering a total area of 5.6 million sq km all over Europe. The distribution pattern of Ni in the European soils (both agricultural and grazing land soils) shows the highest concentrations in correspondence with the Mediterranean area (especially in Greece, the Balcan Peninsula and NW Italy) with average values generally ranging between 40 mg/kg and 140 mg/kg and anomalous areas characterized by peaks higher than 2400 mg/kg. Concentrations between 10 mg/kg and 40 mg/kg characterize Continental Europe north of Alps and, partly, the Scandinavian countries. Lower concentrations (< 10 mg/kg) occurs near the Trans-European Suture Zone, one of the main tectonic borders in Europe, and they are limited on the south by the maximum extent limit of the last glaciation. Cobalt and Cr show distribution patterns similar to Ni in both agricultural and grazing land soils. The maximum concentration peaks of Cobalt and Cr rise up to respectively 126 mg/kg and 696 mg/kg in agricultural soils and up to 255 mg/kg and 577 mg/kg in grazing land soils. Copper distribution in the soils collected across Europe, although has a general correspondence with the patterns of Ni, Co, Cr, shows some peculiarities. Specifically, Cu is characterized by high concentration values (up to 395 mg/kg in agricultural soils and 373 mg/kg in Grazing land soils) also in correspondence with the Roman Comagmatic Province and the south western coast of France characterized by a wide spread of vineyards.

Phytoremediation of strontium contaminated soil by Sorghum bicolor (L.) Moench and soil microbial community-level physiological profiles (CLPPs).

PubMed

Wang, Xu; Chen, Can; Wang, Jianlong

2017-03-01

Phytoremediation of strontium contaminated soil by Sorghum bicolor (L.) Moench was investigated, and the soil microbial community-level physiological profiles (CLPPs) were examined. The growth and the stable strontium ( 88 Sr) accumulations of the energy crop S. bicolor grown on the Sr-spiked soil at the level of 0, 50, 100, 200, and 400 mg/kg soil were characterized through pot soil system after the entire growth period (140 days). Correspondingly, the available content of strontium in soil extracted by Mehlich III extraction solution reached 42.0, 71.9, 151.8, and 242.2 mg/kg, respectively. The Sr-polluted soil microbial community was assessed by a Biolog Eco-plate method. The results showed that the spiked Sr significantly increased the height and the stem biomass weight of the plant. Sr contents in roots, stems, and leaves of the sorghum increased linearly (R 2  > 0.95) with the elevation of the Sr-spiked level in soil. The average Sr concentration in roots, stems, and leaves reached 68.9, 61.3, and 132.6 mg/kg dry weight (DW) under Sr-spiked 400 mg/kg soil, respectively. Sr content in tissues decreased in the order of leaves > roots > stems. The bioconcentration factor (BCF; Sr contents in shoots to soil) values of S. bicolor in soil system was lower than 1 (0.21∼0.39) whether based on the spiked Sr level or on the available Sr level in soil. The transfer factor (TF; Sr contents in shoots to roots) values of S. bicolor in soil system usually is higher than 1 or near to 1 (0.92∼1.29). TF values increased while BCF values decreased as the soil Sr increased. The Biolog Eco-plate assay showed that Sr at the spiked level of 400 mg/kg soil enhanced the soil microbial diversity and activity.

Isolation and characterization of Chilembwe and Sinda Rock Phosphate solubilizing soil microorganisms

USDA-ARS?s Scientific Manuscript database

This study was conducted to isolate and characterize soil microorganisms capable of solubilizing Chilembwe and Sinda rock phosphates readily available in Zambia. Single isolates were obtained by direct plating and enrichment cultures with succinate, cellulose and glucose as the carbon sources. Isola...

Characterization of soil organic matter by FT-IR spectroscopy and its relationship with chlorpyrifos sorption.

PubMed

Parolo, María Eugenia; Savini, Mónica Claudia; Loewy, Ruth Miriam

2017-07-01

Sorption of non-ionic organic compounds to soil is usually expressed as the carbon-normalized partition coefficient (K OC ) assuming that the main factor that influences the amount sorbed is the organic carbon content (OC) of the soil. However, K OC can vary across a range of soils. The influence of certain soil characteristics on the chlorpyrifos K OC values variation for 12 representative soils of the Northpatagonian Argentinian region with different physicochemical properties was investigated for this study. The chlorpyrifos sorption coefficients normalized by the OC content were experimentally obtained using the batch equilibrium method; the K OC values ranged between 9000-20,000 L kg -1 . The soil characteristics assessed were pH, clay content and spectral data indicative of soil organic matter (SOM) quality measured by FT-IR on the whole soil. The bands considered in the spectroscopic analyses were those corresponding to the aliphatic components, 2947-2858 cm -1 (band A) and the hydrophilic components, 1647-1633 cm -1 (band B). A significant relationship was found (R 2  = 0.66) between chlorpyrifos sorption (K OC ) and the variables pH and A/B height band ratio. The correlation between the values predicted by the derived model and the experimental data was significant (r = 0.89 p < 0.05). Thus, this methodology could be used to estimate chlorpyrifos sorption coefficient through the use of a simple, rapid, and environmentally-friendly measurement. K OC analysis in relation to soil properties represents a valuable contribution to the understanding of the attenuation phenomena of the organic contaminants off-site migration in the environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Laboratory-based characterization of plutonium in soil particles using micro-XRF and 3D confocal XRF

DOE PAGES

McIntosh, Kathryn Gallagher; Cordes, Nikolaus Lynn; Patterson, Brian M.; ...

2015-03-29

The investigation of plutonium (Pu) in a soil matrix is of interest in safeguards, nuclear forensics, and environmental remediation activities. The elemental composition of two plutonium contaminated soil particles was characterized nondestructively using a pair of micro X-ray fluorescence spectrometry (micro-XRF) techniques including high resolution X-ray (hiRX) and 3D confocal XRF. The three dimensional elemental imaging capability of confocal XRF permitted the identification two distinct Pu particles within the samples: one external to the Ferich soil matrix and another co-located with Cu within the soil matrix. The size and morphology of the particles was assessed with X-ray transmission microscopy andmore » micro X-ray computed tomography (micro-CT) providing complementary morphological information. Limits of detection for a 30 μm Pu particle are <10 ng for each of the XRF techniques. Ultimately, this study highlights the capability for lab-based, nondestructive, spatially resolved characterization of heterogeneous matrices on the micrometer scale with nanogram sensitivity.« less

Prediction of resilient modulus from soil index properties.

DOT National Transportation Integrated Search

2004-11-01

Subgrade soil characterization in terms of Resilient Modulus (MR) has become crucial for pavement design. For a new : design, MR values are generally obtained by conducting repeated load triaxial tests on reconstituted/undisturbed cylindrical : speci...

Prediction of resilient modulus from soil index properties

DOT National Transportation Integrated Search

2004-11-01

Subgrade soil characterization in terms of Resilient Modulus (MR) has become crucial for pavement design. For a new design, MR values are generally obtained by conducting repeated load triaxial tests on reconstituted/undisturbed cylindrical specimens...

Assessment of acute toxicity tests and rhizotron experiments to characterize lethal and sublethal control of soil-based pests.

PubMed

Agatz, Annika; Schumann, Mario M; French, Bryan W; Brown, Colin D; Vidal, Stefan

2018-03-24

Characterizing lethal and sublethal control of soil-based pests with plant protection products is particularly challenging due to the complex and dynamic interplay of the system components. Here, we present two types of studies: acute toxcity experiments (homogenous exposure of individuals in soil) and rhizotron experiments (heterogeneous exposure of individuals in soil) to investigate their ability to strengthen our understanding of mechanisms driving the effectivness of the plant protection product. Experiments were conducted using larvae of the western corn rootworm Diabrotica virgifera LeConte and three pesticide active ingredients: clothianidin (neonicotinoid), chlorpyrifos (organophosphate) and tefluthrin (pyrethroid). The order of compound concentrations needed to invoke a specific effect intensity (EC 50 values) within the acute toxicity tests was chlorpyrifos > tefluthrin > clothianidin. This order changed for the rhizotron experiments because application type, fate and transport of the compounds in the soil profile, and sublethal effects on larvae also influence their effectiveness in controlling larval feeding on corn roots. Beyond the pure measurement of efficacy through observing relative changes in plant injury to control plants, the tests generate mechanistic understanding for drivers of efficacy apart from acute toxicity. The experiments have the potential to enhance efficacy testing and product development, and might be useful tools for assessing resistance development in the future. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Characterization of plasma sprayed and explosively consolidated simulated lunar soil

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

Powell, S.J.; Inal, O.T.; Smith, M.F.

1997-06-01

Two methods for the use of lunar materials for the construction of shelters on the Moon are being proposed: explosive consolidation of the soil into structural components and plasma spraying of the soil to join components. The plasma-sprayed coating would also provide protection from the intense radiation. In this work, a mare simulant was plasma-sprayed onto a stainless steel substrate. Deposition of a 0.020 inch coating using power inputs of 23, 25, 27 and 29 kW were compared. Hardness of the coatings increased with each increase of power to the system, while porosity at the interface decreased. All coatings exhibitedmore » good adhesion. Simultaneously, an explosively consolidated sample was similarly characterized to afford a comparison of structural features associated with each mode of proposed use.« less

Hyperfine and radiological characterization of soils of the province of Buenos Aires, Argentina

NASA Astrophysics Data System (ADS)

Montes, M. L.; Taylor, M. A.; Mercader, R. C.; Sives, F. R.; Desimoni, J.

2010-03-01

The depth profile concentration of both natural and anthropogenic gamma-ray-emitter nuclides were determined in soil samples collected in an area located at 34° 54.452' S, 58° 8.365' W, down to 50 cm in depth, using an hyper-pure Ge spectrometer. The soil samples were also characterized by means of Mössbauer spectrometry and X-ray diffraction. The activities of 238U and 232Th natural chains remain constant in depth at 41 Bq/kg and 46 Bq/kg, respectively, while the 40K activity increases from 531 Bq/kg to 618 Bq/kg between 2.5 cm y 25.5 cm of depth. The only anthropogenic detected nuclide is 137Cs, whose activity changes form 1.4 Bq/kg to values lower than the detection limit (LD) for depths below 25 cm, exhibiting a maximum at 10 cm beneath the surface. The Mössbauer spectra show two magnetic sextets associated with α-Fe2O3 and Fe3O4, as well as two Fe+3 Fe+2 doublets, probably originated in octahedral and tetrahedral sites of paramagnetic phases. The Fe3+ paramagnetic signal relative fraction increases up to 82% at the expense of the α-Fe2O3 one when de depth increases. No correlation between Fe3O4 and the 137Cs was identificated.

Ecological Screening Values for Surface Water, Sediment, and Soil: 2005 Update

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

Friday, G. P.

2005-07-18

One of the principal components of the environmental remediation program at the Savannah River Site (SRS) is the assessment of ecological risk. Used to support CERCLA, RCRA, and DOE orders, the ecological risk assessment (ERA) can identify environmental hazards and evaluate remedial action alternatives. Ecological risk assessment is also an essential means for achieving DOE's risk based end state vision for the disposition of nuclear material and waste hazards, the decommissioning of facilities, and the remediation of inactive waste units at SRS. The complexity of an ERA ranges from a screening level ERA (SLERA) to a full baseline ERA. Amore » screening level ecological risk assessments, although abbreviated from a baseline risk assessment, is nonetheless considered a complete risk assessment (EPA, 2001a). One of the initial tasks of any ERA is to identify constituents that potentially or adversely affect the environment. Typically, this is accomplished by comparing a constituent's maximum concentration in surface water, sediment, or soil with an ecological screening value (ESV). The screening process can eliminate many constituents from further consideration in the risk assessment, but it also identifies those that require additional evaluation. This document is an update of a previous compilation (Friday, 1998) and provides a comprehensive listing of ecological screening values for surface water, sediment, and soil. It describes how the screening values were derived and recommends benchmarks that can be used for ecological risk assessment. The sources of these updated benchmarks include the U.S. Environmental Protection Agency (EPA), U.S. Fish and Wildlife Service (USFWS), U.S. Geological Survey (USGS), National Oceanic and Atmospheric Administration (NOAA), Oak Ridge National Laboratory (ORNL), the State of Florida, the Canadian Council of Ministers of the Environment (CCME), the Dutch Ministry of the Environment (RIVM), and the scientific literature. It

Geophysical and Geotechnical Characterization of Beta-1,3/1,6-glucan Biopolymer treated Soil

NASA Astrophysics Data System (ADS)

Chang, I.; Cho, G.

2012-12-01

Bacteria or microbes in soil excrete hydrocarbon (e.g. polysaccharide) by-products which are called biopolymers. These biopolymers (or sometime biofilms) recently begun to make a mark on soil erosion control, aggregate stabilization, and drilling enhancement. However, the biological effect on soil behavior (e.g. bio-clogging or bio-cementation) has been poorly understood. In this study, the bio-cementation and bio-clogging effect induced by the existence of β-1,3/1,6-glucan biopolymers in soil were evaluated through a series of geophysical and geotechnical characterization tests in laboratory. According to the experimental test results, as the β-1,3/1,6-glucan content in soil increases, the compressive strength and shear wave velocity increase (i.e., bio-cementation) while the hydraulic conductivity decreases (i.e., bio-clogging) but the electrical conductivity increases due to the high electrical conductivity characteristic of β-1,3/1,6-glucan fibers. Coefficient of consolidation variation with the increases of β-1,3/1,6-glucan content in soil. SEM image of β-1,3/1,6-glucan treated soil. Fibers are form matices with soil particles.

Subgrade characterization for highway pavement design.

DOT National Transportation Integrated Search

2000-12-01

Subgrade soil characterization expressed in terms of Resilient Modulus (MR) has become crucial for pavement design. For a new design, MR : values are generally obtained by conducting repeated triaxial tests on reconstituted/undisturbed cylindrical sp...

Soil Characterization and Site Response of Marine and Continental Environments

NASA Astrophysics Data System (ADS)

Contreras-Porras, R. S.; Huerta-Lopez, C. I.; Martinez-Cruzado, J. A.; Gaherty, J. B.; Collins, J. A.

2009-05-01

An in situ soil properties study was conducted to characterize both site and shallow layer sediments under marine and continental environments. Data from the SCoOBA (Sea of Cortez Ocean Bottom Array) seismic experiment and in land ambient vibration measurements on the urban areas of Tijuana, B. C., and Ensenada, B. C., Mexico were used in the analysis. The goal of this investigation is to identify and to analyze the effect of the physical/geotechnical properties of the ground on the site response upon seismic excitations in both marine and continental environments. The time series were earthquakes and background noise recorded within interval of 10/2005 to 10/2006 in the Gulf of California (GoC) with very-broadband Ocean Bottom Seismographs (OBS), and ambient vibration measurements collected during different time periods on Tijuana and Ensenada urban areas. The data processing and analysis was conducted by means of the H/V Spectral Ratios (HVSPR) of multi component data, the Random Decrement Method (RDM), and Blind Deconvolution (BD). This study presents ongoing results of a long term project to characterize the local site response of soil layers upon dynamic excitations using digital signal processing algorithms on time series, as well as the comparison between the results these methodologies are providing.

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

Characterizing Gas Transport in Wetland Soil-Root Systems with Dissolved Gas Tracer Techniques

NASA Astrophysics Data System (ADS)

Reid, M. C.; Jaffe, P. R.

2016-12-01

Soil fluxes of methane (CH4), nitrous oxide (N2O), and other biogenic gases depend on coupling between microbial and physiochemical processes within soil media. The importance of plant-mediated transport in wetland CH4 emissions is well known, but a generalized understanding of gas transfer between pore water and root aerenchyma, and how this process competes with biogeochemical production/consumption of gases beyond CH4, is incomplete [1]. A lack of experimental approaches to characterize transport processes in complex soil-water-plant systems at field scale has limited efforts to close this knowledge gap. In this presentation we describe dissolved gas tracer techniques to tease apart effects of transport from simultaneous biochemical reaction on trace gas dynamics in soils. We discuss a push-pull test with helium and sulfur hexafluoride gas tracers to quantify in situ root-mediated gas transfer kinetics in a wetland soil [2]. A Damköhler number analysis is introduced to interpret the results and evaluate the balance between biochemical reaction and root-driven gas transfer in controlling the fate of CH4 and N2O in vegetated wetland soils. We conclude with a brief discussion of other problems in soil gas dynamics that can be addressed with gas tracer approaches. [1] Blagodatsky and Smith 2012. Soil physics meets soil biology: Towards better mechanistic prediction of greenhouse gas emissions from soil. Soil Biology and Biochemistry 47, 78-92. [2] Reid et al. 2015. Dissolved gas dynamics in wetland soils: Root-mediated gas transfer kinetics determind via push-pull tracer tests. Water Resour. Res. 51, doi:10.1002/2014WR016803.

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

DOT National Transportation Integrated Search

1966-05-01

This report is an evaluation of the recently developed "Louisiana Slope Value Method". : The conclusion drawn are based on data from 637 separate samples representing nearly all major soil groups in Louisiana that are suitable for cement stabilizatio...

Isolation, evaluation and characterization of Bacillus subtilis from cotton rhizospheric soil with biocontrol activity against Fusarium oxysporum.

PubMed

Gajbhiye, Archana; Rai, Alok R; Meshram, Sudhir U; Dongre, A B

2010-07-01

Present investigation is based on the isolation of Bacillus subtilis from cotton rhizosphere and their evaluation as biocontrol agent against Fusarium oxysporum. The production of extracellular hydrolytic enzyme was studied for determining the antagonism. 43% of 21 isolates were identified under the B. subtilis group on the basis of biochemical characterization. 38% isolates showed competitive activity against Fusarium oxysporum and exhibit more than 50% mycelial inhibition in dual culture bioassay. The pot assay of cotton by seed treatment and soil amendment technique under green house condition showed the competent activity of the isolates in preventing the wilting of cotton seedlings due to F. oxysporum infection. SVI values of 30 day old seedlings indicated that the soil inoculation with B. subtilis BP-2 and seed treatment with B. subtilis BP-9 significantly promoted the growth of cotton seedlings. RAPD profiling revealed the diversity in the Bacillus subtilis group, ranging from 10 to 32%. The discriminative pattern among the isolates belonging to the same species was validated by 16S rDNA partial sequencing which identified them into four different strains of B. subtilis.

Some physicochemical properties of surface layer soils shelterbelts in agricultural landscape

NASA Astrophysics Data System (ADS)

Jaskulska, R.; Szajdak, L.

2009-04-01

Shelterbelts belong to very efficient biogeochemical barriers. They decrease the migration of chemical compounds between ecosystems. The investigations were carried out in the Chlapowski's Agroecological Park in Turew situated 40 km South-West of Poznań, Poland. This area is located on loamy soils, which contains 70% cultivated fields and 14% shelterbelts and small afforestations. The shelterbelts represent different ages and the content of plants as well as humus quantity in surface layer. The first one is 100-year-old shelterbelt, where predominant species is Crataegus monogyna Jacq., Quercus rober L., and Fraxinus excelsior (L.) and is characterized by a well-developed humus level. The other one is 14-year-old shelterbelt. It includes 13 species of trees and revealed a small amount of humus. The soil under both shelterbelts is mineral, grey-brown podzolic in surface layer compound from light loamy sands and weakly loamy sands. The soil samples were taken from surface layer (0-20 cm). pH 1N KCl, hydrolytic acidity, cation-exchange capacity, total proper area, total organic carbon and dissociation constants were determined in soils. The study showed that the soil under shelterbelts revealed acidic properties. It was observed that soils of 100-year-old shelterbelt characterizing lowest values pH = 4.2 revealed highest values of hydrolytic acidity equaled to 7.8 cmol(+)ṡkg-1. The physicochemical properties of investigated soils shoved specific surface areas (22.8 m2ṡg-1), cationic sorptive capacity (12.9 cmol(+)ṡkg-1). TOC (1.6%) 100-year-old shelterbelt was higher than in 14-year-old shelterbelt. The dissociation constants were determined by potentiometric titration. This investigation revealed that the pK value was the highest in the humus of 100-year-old shelterbelt (pKa = 3.1). However, soils of 14-year-old shelterbelt characterized by the lovest pK equaled to 2.8. The surface layer soils shelterbelts in agricultural landscape with good humus development

Interpolation Approaches for Characterizing Spatial Variability of Soil Properties in Tuz Lake Basin of Turkey

NASA Astrophysics Data System (ADS)

Gorji, Taha; Sertel, Elif; Tanik, Aysegul

2017-12-01

Soil management is an essential concern in protecting soil properties, in enhancing appropriate soil quality for plant growth and agricultural productivity, and in preventing soil erosion. Soil scientists and decision makers require accurate and well-distributed spatially continuous soil data across a region for risk assessment and for effectively monitoring and managing soils. Recently, spatial interpolation approaches have been utilized in various disciplines including soil sciences for analysing, predicting and mapping distribution and surface modelling of environmental factors such as soil properties. The study area selected in this research is Tuz Lake Basin in Turkey bearing ecological and economic importance. Fertile soil plays a significant role in agricultural activities, which is one of the main industries having great impact on economy of the region. Loss of trees and bushes due to intense agricultural activities in some parts of the basin lead to soil erosion. Besides, soil salinization due to both human-induced activities and natural factors has exacerbated its condition regarding agricultural land development. This study aims to compare capability of Local Polynomial Interpolation (LPI) and Radial Basis Functions (RBF) as two interpolation methods for mapping spatial pattern of soil properties including organic matter, phosphorus, lime and boron. Both LPI and RBF methods demonstrated promising results for predicting lime, organic matter, phosphorous and boron. Soil samples collected in the field were used for interpolation analysis in which approximately 80% of data was used for interpolation modelling whereas the remaining for validation of the predicted results. Relationship between validation points and their corresponding estimated values in the same location is examined by conducting linear regression analysis. Eight prediction maps generated from two different interpolation methods for soil organic matter, phosphorus, lime and boron parameters

Integration of Magnetic and Geotechnical methods for Shallow Subsurface Soil Characterization at Sungai Batu, Kedah, Malaysia

NASA Astrophysics Data System (ADS)

Samuel, Y. M.; Saad, R.; Muztaza, N. M.; Saidin, M. M.; Muhammad, S. B.

2018-04-01

Magnetic and geotechnical methods were used for shallow subsurface soil characterization at Sungai Batu, Kedah, (Malaysia). Ground magnetic data were collected along a survey line of length 160 m long at 2 m constant station spacing, while soil drilling using hand auger was conducted at 21 m on the survey line using 0.2 m sampling interval drilled to a depth of 5 m. Result from the processed magnetic profile data shows distribution of magnetic residuals in the range of -4.55 to 1.61 nT, with magnetic low (-4.55 nT to -0.058 nT) and were identified at distances 4 m, 10 to 16 m, 20 to 26 m, 58 m, 82 m, 104 to 106 m, 118 m, and 124 to 140 m. The magnetic lows are attributes of sediments. The result from the soil drilling shows sticky samples with variable sizes, greyish to brownish / reddish in colour, and some of the samples show the presence of shiny and black spots. The characteristics of the samples suggest the soil as a by-product of completely weathered rock; weak with high water content and classified as Grade V soil. The study concludes; integration of geophysical and geotechnical methods aided in characterizing the subsurface soil at Sungai Batu. The result was correlated with previous studies and confirms the importance of integrated approach in minimising ambiguity in interpretation.

Uranium partition coefficients (Kd) in forest surface soil reveal long equilibrium times and vary by site and soil size fraction.

PubMed

Whicker, Jeffrey J; Pinder, John E; Ibrahim, Shawki A; Stone, James M; Breshears, David D; Baker, Kristine N

2007-07-01

The environmental mobility of newly deposited radionuclides in surface soil is driven by complex biogeochemical relationships, which have significant impacts on transport pathways. The partition coefficient (Kd) is useful for characterizing the soil-solution exchange kinetics and is an important factor for predicting relative amounts of a radionuclide transported to groundwater compared to that remaining on soil surfaces and thus available for transport through erosion processes. Measurements of Kd for 238U are particularly useful because of the extensive use of 238U in military applications and associated testing, such as done at Los Alamos National Laboratory (LANL). Site-specific measurements of Kd for 238U are needed because Kd is highly dependent on local soil conditions and also on the fine soil fraction because 238U concentrates onto smaller soil particles, such as clays and soil organic material, which are most susceptible to wind erosion and contribute to inhalation exposure in off-site populations. We measured Kd for uranium in soils from two neighboring semiarid forest sites at LANL using a U.S. Environmental Protection Agency (EPA)-based protocol for both whole soil and the fine soil fraction (diameters<45 microm). The 7-d Kd values, which are those specified in the EPA protocol, ranged from 276-508 mL g-1 for whole soil and from 615-2249 mL g-1 for the fine soil fraction. Unexpectedly, the 30-d Kd values, measured to test for soil-solution exchange equilibrium, were more than two times the 7-d values. Rates of adsorption of 238U to soil from solution were derived using a 2-component (FAST and SLOW) exponential model. We found significant differences in Kd values among LANL sampling sites, between whole and fine soils, and between 7-d and 30-d Kd measurements. The significant variation in soil-solution exchange kinetics among the soils and soil sizes promotes the use of site-specific data for estimates of environmental transport rates and suggests

Modern soil system constraints on reconstructing deep-time atmospheric CO2

NASA Astrophysics Data System (ADS)

Montañez, Isabel P.

2013-01-01

Paleosol carbonate-based estimates of paleo-atmospheric CO2 play a prominent role in constraining radiative-forcing and climate sensitivity in the deep-time. Large uncertainty in paleo-CO2 estimates made using the paleosol-carbonate CO2-barometer, however, arises primarily from their sensitivity to soil-respired CO2 (S(z)). This parameter is poorly constrained due to a paucity of soil CO2 measurements during carbonate formation in modern soils and a lack of widely applicable proxies of paleo-soil CO2. Here the δ13C values of carbonate and soil organic matter (SOM) pairs from 130 Holocene soils are applied to a two-component CO2-mixing equation to define soil order-specific ranges of soil CO2 applicable for constraining S(z) in their corresponding paleosol analogs. Equilibrium carbonate-SOM pairs, characterized by Δ13Ccarb-SOM values of 12.2-15.8‰, define a mean effective fractionation of 14.1‰ and overall inferred total soil CO2 contents during calcite formation of <1000-10,000 ppmv. For those Aridisols and Alfisols, characterized by a net soil-moisture deficit, and their paleosol analogs (Calcisols and Argillisols), a best estimate of S(z) during calcite formation is 1500-2000 ppmv (range of 500-2500 ppmv). Overall higher values (2000-5000 ppmv) are indicated by the subset of these soils characterized by higher moisture content and productivity. Near atmospheric levels (400 ± 200 ppmv) of estimated S(z) are indicated by immature soils, recording their low soil productivity. Vertisols define the largest range in total soil CO2 (<1000 to >25,000 ppmv) reflecting their seasonally driven dynamic hydrochemistry. A S(z) range of 1000-10,000 ppmv is suggested for paleo-Vertisols for which calcite precipitation can be constrained to have occurred in an open system with two-component CO2 mixing, with a best estimate of 2000 ppmv ± 1000 ppmv appropriate for paleo-Vertisols for which evidence of protracted water saturation is lacking. Mollisol pairs define a best

Determination of threshold value of soil water content for field and vegetable plants with lysimeter measurements

NASA Astrophysics Data System (ADS)

Knoblauch, S.

2009-04-01

Both the potential water consumption of plants and their ability to withdraw soil water are necessary in order to estimate actual evapotranspiration and to predict irrigation timing and amount. In relating to root water uptake the threshold value at which plants reducing evapotranspiration is an important parameter. Since transpiration is linearly correlated to dry matter production, under the condition that the AET/PET-Quotient is smaller than 1.0 (de Wit 1958, Tanner & Sinclair 1983), the dry matter production begins to decline too. Plants respond to drought with biochemical, physiological and morphological modifications in order to avoid damages, for instance by increasing the root water uptake. The objective of the study is to determine threshold values of soil water content and pressure head respectively for different field and vegetable plants with lysimeter measurements and to derive so called reduction functions. Both parameter, potenzial water demand in several growth stages and threshold value of soil water content or pressure head can be determined with weighable field lysimeter. The threshold value is reached, when the evapotranspiration under natural rainfall condition (AET) drop clearly (0.8 PET) below the value under well watered condition (PET). Basis for the presented results is the lysimeter plant Buttelstedt of the Thuringian State Institute of Agriculture. It consist of two lysimeter cellars, each with two weighable monolithic lysimeters. The lysimeter are 2.5 m deep with a surface area of 2 m2 to allow a non-restrictive root growth and to arrange a representative number of plants. The weighing accuracy amounts to 0.05 mm. The percolating water is collected by ceramic suction cups with suction up to 0.3 MPa at a depth of 2.3 m. The soil water content is measured by using neutron probe. One of the two lysimeter cellars represents the will irrigated, the other one the non irrigated and/or reduced irrigated part of field. The soil is a Haplic

A study of the effectiveness of the use of gypsum and volcanic ash against the stability of clay soil in terms of UCT and CBR values

NASA Astrophysics Data System (ADS)

Roesyanto; Iskandar, R.; Hastuty, IP; Lubis, AIU

2018-02-01

Soil stabilization is an effort to improve engineering properties of soil. The conventional soil stabilization is by adding additives to the soil such as Portland cement, lime, and bitumen. The clay stabilization research was done by adding gypsum and volcanic ash. The research purposes were to find out the value of engineering properties of clay due to the addition of 2% gypsum and 2% - 15% volcanic ash. The soil was classified as Clay - Low Plasticity (CL) based on USCS and was classified as A-7-6 (10) based on AASHTO classification system. The UCT values of original soil and original soil plus 2% gypsum were 1.40 kg/cm2 and 1.66 kg/cm2 respectively. The CBR soaked and unsoaked values of original soil were 4.44% and 6.28% correspondingly. Meanwhile, CBR soaked and CBR unsoaked values of original soil plus 2% gypsum were 6.74% and 8.02% respectively. The research results showed that the additives materials of gypsum and volcanic ash improved the engineering properties of clay. The UCT result from the stabilized soil by 2% gypsum and 10% volcanic ash gave value of 2.79 kg/cm2 (increased 99.28% from original soil). For CBR test, the most effective mixture were in variation of 2% gypsum and 9% volcanic ash which gave value of 9.07% (104.27% increase from original soil) for CBR soaked and 10.29% (63.85% increase from original soil) for CBR unsoaked. The stabilized soil with 2% gypsum and 9% volcanic ash was classified as CL based on USCS and was classified as A-6 (4) based on AASHTO classification system.

Characterization of commercial iron chelates and their behavior in an alkaline and calcareous soil.

PubMed

Cantera, Rodrigo G; Zamarreño, Angel M; García-Mina, José M

2002-12-18

Iron deficiency is a common problem for many plants grown in alkaline and calcareous soils. To correct this problem, iron is supplied to plants as chelates. Several iron chelates are sold under diverse trademarks with different characteristics. This work evaluated 18 commercial products containing the most representative chelated iron sources used in agricultural practice in Spain when the study was done, namely the ferric chelates of EDDHA, EDDHMA, EDDCHA, EDDHSA, EDTA, and DTPA. The chelates were comprehensively characterized and quantitated by several techniques, including several chromatographic methods. Iron and chelate dynamics in soil were also studied in a model alkaline and calcareous soil. Results indicate that, in this model soil, among the different iron compounds studied only FeEDDHA and analogues have the capacity to maintain soluble iron in soil solution over time. These results are in agreement with general experience under field conditions. Furthermore, among the different ortho-ortho isomers of FeEDDHA's, FeEDDHSA and FeEDDCHA showed greater capacity than FeEDDHA and FeEDDHMA to maintain the chelated iron in soil solution over time.

Effects of Long-term Soil and Crop Management on Soil Hydraulic Properties for Claypan Soils

USDA-ARS?s Scientific Manuscript database

Regional and national soil maps and associated databases of soil properties have been developed to help land managers make decisions based on soil characteristics. Hydrologic modelers also utilize soil hydraulic properties provided in these databases, in which soil characterization is based on avera...

Characterization of wet aggregate stability of soils by ¹H-NMR relaxometry.

PubMed

Buchmann, C; Meyer, M; Schaumann, G E

2015-09-01

For the assessment of soil structural stability against hydraulic stress, wet sieving or constant head permeability tests are typically used but rather limited in their intrinsic information value. The multiple applications of several tests is the only possibility to assess important processes and mechanisms during soil aggregate breakdown, e.g. the influences of soil fragment release or differential swelling on the porous systems of soils or soil aggregate columns. Consequently, the development of new techniques for a faster and more detailed wet aggregate stability assessment is required. (1)H nuclear magnetic resonance relaxometry ((1)H-NMR relaxometry) might provide these requirements because it has already been successfully applied on soils. We evaluated the potential of (1)H-NMR relaxometry for the assessment of wet aggregate stability of soils, with more detailed information on occurring mechanisms at the same time. Therefore, we conducted single wet sieving and constant head permeability tests on untreated and 1% polyacrylic acid-treated soil aggregates of different textures and organic matter contents, subsequently measured by (1)H-NMR relaxometry after percolation. The stability of the soil aggregates were mainly depending on their organic matter contents and the type of aggregate stabilization, whereby additional effects of clay swelling on the measured wet aggregate stability were identified by the transverse relaxation time (T2) distributions. Regression analyses showed that only the percentage of water stable aggregates could be determined accurately from percolated soil aggregate columns by (1)H-NMR relaxometry measurements. (1)H-NMR relaxometry seems a promising technique for wet aggregate stability measurements but should be further developed for nonpercolated aggregate columns and real soil samples. Copyright © 2014 John Wiley & Sons, Ltd.

Hydrodynamic characterization of soils within a representative watershed in northeast Brazil

NASA Astrophysics Data System (ADS)

Sales, E. G.; Almeida, C. D. N.; Farias, A. S.; Coelho, V. H. R.

2014-09-01

Studies about the infiltration of water in the soil, based on hydraulic conductivity and retention curve, are important to simulate hydrological processes and pollution fluxes. This paper aims to present the hydrodynamic soil behaviour of the Gramame watershed, located in northeast Brazil. This basin is representative of several other watersheds located on the coastal region of northeast Brazil, where sugarcane crops constitute the main land use. For this study, three different land uses and land covers were considered: sugarcane crops, pineapple crops and Atlantic Forest, which is the native forest of this region. The Beerkan method and the BEST program were used in order to get retention and hydraulic conductivity curves. The results show that the highest values of hydraulic conductivity were obtained at points located in native vegetation and deforestation impacts the soil hydrodynamic characteristics.

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

Chemical characterization of iron-mediated soil organic matter stabilization in tropical subsoils

NASA Astrophysics Data System (ADS)

Coward, E.; Plante, A. F.; Thompson, A.

2015-12-01

Tropical forest soils contribute disproportionately to the poorly-characterized and persistent deep soil carbon (C) pool. Highly-weathered and often extending one to two meters deep, these soils also contain an abundance of semicrystalline, Fe- and Al-containing short-range-order (SRO) minerals, metastable derivatives of framework silicate and ferromagnesian parent materials. SRO minerals are capable of soil organic matter (SOM) stabilization through sorption or co-precipitation, a faculty enhanced by their high specific surface area (SSA). As such, SRO-mediated organomineral associations may prove a critical, yet matrix-selective, driver of SOM stabilization capacity in tropical soils, particularly at depth. Surface (0-20 cm) and subsoil (50-80 cm) samples were taken from 20 quantitative soil pits dug in the Luquillo Critical Zone Observatory, located in northeast Puerto Rico. Soils were stratified across granodiorite and volcaniclastic parent materials, spanning primary mineral contents of 5 to 40%. Selective dissolution procedures were used to isolate distinct forms of Fe-C interactions: (1) sodium pyrophosphate to isolate organo-mineral complexes, (2) hydroxylamine and (3) oxalate to isolate SRO phases, and (4) inorganic dithionite to isolate crystalline Fe oxides. Extracts were analysed for dissolved organic C (DOC) and Fe and Al concentrations to estimate SOM associated with each mineral phase. Soils were also subjected to SSA analysis, 57Fe-Mössbauer spectroscopy and X-ray diffraction before and after extraction to determine the contribution of extracted mineral phases to SOM stabilization capacity. Preliminary results indicate a dominance of secondary (hydr)oxides and kaolin minerals in surface soils, strongly driven by parent material. With depth, however, we observe a marked shift towards SRO mineral phases across both parent materials, suggesting that SRO-mediated organomineral associations are significant contributors to observed C storage in tropical

Soil health in the Mediterranean region: Development and consolidation of a multifactor index to characterize the health of agricultural lands

NASA Astrophysics Data System (ADS)

Gil, Eshel; Guy, Levy; Oshri, Rinot; Michael, Borisover; Uri, Yermiyahu; Leah, Tsror; Hanan, Eizenberg; Tal, Svoray; Alex, Furman; Yael, Mishael; Yosef, Steinberger

2017-04-01

that are difficult to control), soil-borne diseases, and pesticide fixation and release. We, a group of more than ten Israeli scientists, have recently started a multidisciplinary study aimed at developing and consolidating a multiparameter soil-health index to characterize the health of agricultural soils in Mediterranean regions. Such an index will enable us to quantitatively evaluate the contribution of different cultivation managements and reclamation activities. In order to achieve our goal, a three steps approach was adopted: 1) acquiring a multivariate component database (about 42 variables) that will be quantified in the laboratory and in the fields in two soil types of the most important agricultural region of Israel, at three different soil usage: orchard, field crops and "native" as a reference. The acquired biological, physical, and chemical variables comprise basic quantitative values in the soil health of agricultural land; (2) developing a multivariate soil-health index based on a multivariate correlation, in addition to conducting meetings with farmers and panel discussions with other scientists in the field. The whole study angled to evaluate the relative contribution of each of the biotic and abiotic parameters in order to develop a model related to soil health; and (3) to validate the efficiency of the developed index for characterizing and assessing soil-health state at the various agricultural regions in Israel where conservation and reclamation activities took place. We are open to extend our study to other areas with a Mediterranean climate and look forward to establishing cooperative activities with other research groups.

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR SOIL CHARACTERIZATION (UA-L-11.1)

EPA Science Inventory

The purpose of this SOP is to describe the procedures to be followed in splitting and determining the grain size characteristics, electrical conductivity, and pH of the "Composite Soil" and "Foundation Soil" samples. This procedure applies to the general characterization of sedi...

Soil

USDA-ARS?s Scientific Manuscript database

Soil is a diverse natural material characterized by solid, liquid, and gas phases that impart unique chemical, physical, and biological properties. Soil provides many key functions, including supporting plant growth and providing environmental remediation. Monitoring key soil properties and processe...

Microbiological characterization of vegetables and their rhizosphere soil in Eastern Poland.

PubMed

Kłapeć, Teresa; Wójcik-Fatla, Angelina; Cholewa, Alicja; Cholewa, Grażyna; Dutkiewicz, Jacek

2016-12-23

The aim of this study was to investigate the bacteriological quality of 5 kinds of vegetables (lettuce, dill, radish, beetroot, carrot) and their rhizosphere soil, originating from conventional farms located in the Lublin Province of Eastern Poland. A total number of 35 samples of fresh vegetables (FV) taken immediately from soil, 35 samples of soil from rhizosphere of these vegetables (SR) and 35 samples of vegetables sold at retail in the markets in Lublin (VR) were examined. The samples were analysed for the content of: aerobic mesophilic bacteria (AMB) grown at 30°C and 37°C, Gram-negative bacteria of Enterobacteriaceae family, faecal coliform (FC) bacteria, Salmonella spp., and Clostridium perfringens. Median AMB values determined at 30°C for FV, SR and VR were 5.27, 5.00, and 5.00 log 10 CFU g -1 , respectively, being significantly greater compared to those recorded at 37°C. The exceeding of the threshold value of 6.0 log 10 CFU g -1 proposed by Gelosa (1998) was noted only in 5 FV samples grown at 30°C (14.3%), and in 3 FV samples grown at 37°C (8.6%). The threshold value was never exceeded in SR and VR samples. Median concentrations of Enterobacteriaceae determined for FV, SR and VR were 4.03, 3.87, and 3.04 log 10 CFU g -1 , respectively. Eleven species of Enterobacteriaceae were identified in the FV, SR and VR samples. The percent of samples containing Escherichia coli was greatest for VR (22.9%), smaller for FV (17.1%) and smallest for SR (5.7%). The median concentrations of the faecal coliform bacteria (FC), determined by culture at 44°C, were low, amounting to 1.000 log 10 CFU g -1 for FV and SR and 0.00 for VR. All examined vegetable and soil samples tested negative for the presence of Salmonella. The median concentrations of Clostridium perfringens were low, amounting to 0.00 log 10 CFU g -1 for all categories of samples. This bacterium was relatively common in soil samples with the prevalence of 40.0%, but very rare in vegetable samples

Soil pollution in Central district of Saint-Petersburg (Russia)

NASA Astrophysics Data System (ADS)

Terekhina, Natalia; Ufimtseva, Margarita

2015-04-01

Analysis of soil samples of upper horizon for the content of chemical elements (Fe, Mn, Cu, Zn, Pb, Ni, Cr, Co, Cd, Ba, Sr) was carried out by atomic emission with inductively coupled plasma. A relative indicator of soil contamination degree is a concentration coefficient, representing the ratio of metal content in tested soil samples to the local background value of the corresponding element. Total pollution index is calculated by the concentration coefficients, which are greater than 1, taking into account the hazard class of metals (1 class - Zn, Pb ,Cd; 2 - class Cr, Ni, Cu ,Со; 3 class - Fe, Mn, Sr, Ba). Analysis of trace element of urban soils demonstrated mosaic patterns of pollution for Central district. The method of correlation sets constructing and factor analysis revealed three groups of chemical elements having a strong and significant association with each other: Pb-Cu-Cd-Zn-Ba, Ni-Cr-Co, Fe-Mn. Elements of the first group are characterized by high values of concentration coefficient and are the main pollutants - their average content is 3-11 times higher than background values. Strontium does not have strong correlation with the other elements, and its lowest concentration coefficient indicates that the element can not be regarded as a pollutant. The spatial distribution of the total pollution index identified several sources of pollution, the origin of which may be different. The main reason is probably the impact of vehicle emissions, although local pollution of soil is possible (the soils, contaminated during reconstruction of lawns, dumping of construction materials, etc.). Differentiated assessment of database shows that 48% of samples refer to dangerous pollution category, 37% - to moderately dangerous category, 15% - to allowable category. Thus, almost half of the district is characterized as dangerous in terms of soil contamination. Solution of the problem of soil contamination is recommended in three ways: reducing the intensity of

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)

Soil organic matter stabilization in grazing highland soils from the Andean Plateau

NASA Astrophysics Data System (ADS)

Muñoz, M. A.; Faz, A.; Zornoza, R.

2012-04-01

Grasslands comprise approximately 40% of the earth's land area and play a critical role in the global carbon cycle. Apolobamba is a grazing highland located in the Andean Plateau where sustainable vicuna (Vicugna vicugna) management programme is carried out. Understanding the soil properties and the organic matter dynamics is fundamental to determine the grazing impacts in the carbon reservoirs. However, the labile and recalcitrant fractions of C have not been widely studied under field conditions, especially in high grasslands. The objectives of this survey were to: (i) achieve a soil characterization through general physico-chemical properties and (ii) study soil organic matter stabilization through recalcitrant and labile carbon budgets in Apolobamba. Regarding the lastly vicuna censuses carried out in the studied area, eight representative zones with different vicuna densities were selected and soil samples were collected. Other characteristics were also considered to select the study zones: (1) alpaca densities, (2) vegetation communities (3) plant cover and (4) landscape and geo-morphological description. Recalcitrant and water soluble organic carbon were determined as well as recalcitrant index. General soil characterization showed strongly acid and no saline soils with high cation exchange capacity and sandy-loam and loam textures. Total nitrogen contents indicated no limitation for the native vegetation growth. In general, no relationships were found among general soil properties, vicuna and alpaca densities; however, zones with highest alpaca density could be prone to soil erosion based on the available P distribution and the texture results. Additionally, a negative alpaca grazing influence in the soil organic carbon stocks was observed. On the other hand, high soil recalcitrant carbon contents (3.7 ± 0.3 kg m-2) and recalcitrance index (0.8 ± 0.1) were found. Likewise, labile C exhibited similar values to those obtained from researchers conducted in

Characterization of P status in forest soils: stocks, fluxes and models

NASA Astrophysics Data System (ADS)

Achat, D. L.; Morel, C.; Bakker, M.; Augusto, L.; Gallet-Budynek, A.; Gonzalez, M.; Jonard, M.

2010-12-01

Phosphorus (P) is a critical limiting factor of plant growth and production in many ecosystems, which often require to be fertilized. However, there is an increasing concern regarding appropriate local and global management of phosphorus resources, since the existing finite phosphate reserves are rapidly being depleted. This implies to understand what processes (biological, physico-chemical) are governing soil P availability in agroecosystems, and in particular in forests, which will be increasingly managed for their C-sink potential in the future. We characterized the P status in forest soils of the largest managed pine forest in Europe (Landes of Gascogne, southwest of France) using isotopic and extraction methods, as well as modelling approaches. Total P concentration in topsoils were extremely low, ranging from 7 to 195 mg Pkg-1. The concentration of phosphate ions in solution decreased with depth and was related to the Al and Fe oxide content, which controlled the diffusion of P from the soil solid phase to the solution. The gross amount of diffusive P in one week as determined by 32P isotopic dilution in batch experiments was low, ranging from 0.2 to 52 mg P kg-1 in the topsoil layer, and could be predicted by pedotransfer functions built on the Al and Fe oxide and soil organic matter contents. Organic P represented 80% of total P in litter and 60% in the surface mineral soil layer, suggesting a higher contribution of biological processes to soil P cycling. Biological mineralization of organic P was quantified using a long-term incubation study (154 days) of a low-sorbing soil labelled with 33P, associated with a batch experiment with 32P labelled soil: gross mineralization of dead soil organic matter and diffusive phosphate P were low (<1 mg kg-1 ) compared to the remineralization of microbial P (14mg kg-1). A modelling approach combined to these isotopic measurements showed that 80 % of microbial P turned over very quickly (5-9 days), while 20% turned over

Geochemical characterization of elements in Vitis vinifera cv. Negroamaro grape berries grown under different soil managements.

PubMed

Pepi, Salvatore; Coletta, Antonio; Crupi, Pasquale; Leis, Marilena; Russo, Sabrina; Sansone, Luigi; Tassinari, Renzo; Chicca, Milvia; Vaccaro, Carmela

2016-04-01

The present geochemical study concerns the impact of viticultural practices in the chemical composition of the grape cultivar "Negroamaro" in Apulia, a southern Italian region renowned for its quality wine. Three types of soil management (SM), two cover cropping with different mixtures, and a soil tillage were considered. For each SM, the vines were irrigated according to two irrigation levels. Chemical composition of soil and of berries of Vitis vinifera cultivar "Negroamaro" were analyzed by X-ray fluorescence, inductively coupled plasma-mass spectrometry and multivariate statistics (linear discrimination analysis). In detail, we investigated major and trace elements behavior in the soil according to irrigation levels, the related index of bioaccumulation (BA) and the relationship between trace element concentration and soil management in "Negroamaro" grapes. The results indicate that soil management affects the mobility of major and trace elements. A specific assimilation of these elements in grapes from vines grown under different soil management was confirmed by BA. Multivariate statistics allowed to associate the vines to the type of soil management. This geochemical characterization of elements could be useful to develop fingerprints of vines of the cultivar "Negroamaro" according to soil management and geographical origin.

Characterization of bacterial communities and functions of two submerged soils from San Vitale park (Italy)

NASA Astrophysics Data System (ADS)

Mocali, Stefano; Chiellini, Carolina; Lagomarsino, Alessandra; Ferronato, Chiara; Vittori Antisari, Livia; Vianello, Gilmo

2015-04-01

Subaqueous soils has been introduced in the last edition of the Keys to Soil Taxonomy (Soil surveystaff, 2014), to describe soils covered by a water column of up to 2.5 m where different pedogenetic processes can be recognized. However, the role of bacterial community structure and function in such environments and its potential use as pedogenetic indicator is still largely unknown. Two submerged soils (WAS-2 and WAS-4) were collected from San Vitale park (Italy), a site where the evolution of the landscape from subaqueous wetland to interdunal and dunal system, and the interfacing of freshwater with saltwater, made this site particularly suitable for examining the pedogenetic indicators which can characterize and predict the soil hydromorphism in trasitional ecosystems. The two soils were classified and their physicochemical and morphological features were investigated. Selective media were used to isolate both culturable aerobic and anaerobic (microaerophilic) bacteria associated with each horizon. In WAS-2 seven horizons were identified (depths 4-0, 0-6, 6-13, 13-20, 20-36, 36-59/60, and 59/60-83 cm) while in WAS-4, five horizons were identified (depths 0-14, 14-20, 20-40, 40-45, 45-100 cm) for a total of 12 horizons (samples). For each sample, aerobic bacterial plate count was performed on solid LB medium, coupled with microaerophilic bacterial plate count either on SA500 minimal medium and AYE medium (0.5% soft agar each). Molecular identification (16S rRNA gene sequencing) of ~100 strains isolated from each of the three used medium was performed, for a total of ~300 strains for each sample. To complete the characterization of the microbial communities in all horizons, Next Generation Sequencing (NGS) analysis was carried out with 454 platform on each of the 12 samples. Moreover, the N2O and CH4 emissions were determined from each pedon. All the parameters were used to highlight the similarities and the differences between and within the pedons. The results

Soil organic carbon distribution in roadside soils of Singapore.

PubMed

Ghosh, Subhadip; Scharenbroch, Bryant C; Ow, Lai Fern

2016-12-01

Soil is the largest pool of organic carbon in terrestrial systems and plays a key role in carbon cycle. Global population living in urban areas are increasing substantially; however, the effects of urbanization on soil carbon storage and distribution are largely unknown. Here, we characterized the soil organic carbon (SOC) in roadside soils across the city-state of Singapore. We tested three hypotheses that SOC contents (concentration and density) in Singapore would be positively related to aboveground tree biomass, soil microbial biomass and land-use patterns. Overall mean SOC concentrations and densities (0-100 cm) of Singapore's roadside soils were 29 g kg -1 (4-106 g kg -1 ) and 11 kg m -2 (1.1-42.5 kg m -2 ) with median values of 26 g kg -1 and 10 kg m -2 , respectively. There was significantly higher concentration of organic carbon (10.3 g kg -1 ) in the top 0-30 cm soil depth compared to the deeper (30-50 cm, and 50-100 cm) soil depths. Singapore's roadside soils represent 4% of Singapore's land, but store 2.9 million Mg C (estimated range of 0.3-11 million Mg C). This amount of SOC is equivalent to 25% of annual anthropogenic C emissions in Singapore. Soil organic C contents in Singapore's soils were not related to aboveground vegetation or soil microbial biomass, whereas land-use patterns to best explain variance in SOC in Singapore's roadside soils. We found SOC in Singapore's roadside soils to be inversely related to urbanization. We conclude that high SOC in Singapore roadside soils are probably due to management, such as specifications of high quality top-soil, high use of irrigation and fertilization and also due to an optimal climate promoting rapid growth and biological activity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluation and characterization of anti-estrogenic and anti-androgenic activities in soil samples along the Second Songhua River, China.

PubMed

Li, Jian; Wang, Yafei; Kong, Dongdong; Wang, Jinsheng; Teng, Yanguo; Li, Na

2015-11-01

In the present study, re-combined estrogen receptor (ER) and androgen receptor (AR) gene yeast assays combined with a novel approach based on Monte Carlo simulation were used for evaluation and characterization of soil samples collected from Jilin along the Second Songhua River to assess their antagonist/agonist properties for ER and AR. The results showed that estrogenic activity only occurred in the soil samples collected in the agriculture area, but most soil samples showed anti-estrogenic activities, and the bioassay-derived 4-hydroxytamoxifen equivalents ranged from N.D. to 23.51 μg/g. Hydrophilic substance fractions were determined as potential contributors associated with anti-estrogenic activity in these soil samples. Moreover, none of the soil samples exhibited AR agonistic potency, whereas 54% of the soil samples exhibited AR antagonistic potency. The flutamide equivalents varied between N.D. and 178.05 μg/g. Based on Monte Carlo simulation-related mass balance analysis, the AR antagonistic activities were significantly correlated with the media polar and polar fractions. All of these results support that this novel calculation method can be adopted effectively to quantify and characterize the ER/AR agonists and antagonists of the soil samples, and these data could help provide useful information for future management and remediation efforts.

14C tebuconazole degradation in Colombian soils.

PubMed

Mosquera, C S; Martínez, M J; Guerrero, J A

2010-01-01

Tebuconazole is a fungicide used on onion crops (Allium Fistulosum L) in Colombia. Persistence of pesticides in soils is characterized by the half-life (DT50), which is influenced by their chemical structure, the physical and chemical properties of the soil and the previous soil history. Based on its structural and chemical properties, tebuconazole should be expected to be relatively persistent in soils. Laboratory incubation studies were conducted to evaluate persistence and bond residues of 14C tebuconazole in three soils, two inceptisol (I) and one histosol (H). Textural classifications were: loam (101), loamy sand (102) and loam (H03), respectively. Data obtained followed a first-order degradation kinetics (R2 > or = 0.899) with DT50 values between 158 and 198 days. The production of 14CO2 from the 14C-ring-labelled test chemicals was very low and increased slightly during 63 days in all cases. The methanol extractable 14C-residues were higher than aqueous ones and both decreased over incubation time for the three soils. The formation of bound 14C-residues increased with time and final values were 11.3; 5.55 and 7.87% for 101, 102 and H03 respectively. Soil 101 showed the lowest mineralization rate and the highest bound residues formation, which might be explained by the clay fraction content. In contrast, an inverse behavior was found for soils 102 and H03, these results might be explained by the higher soil organic carbon content.

Fungi from geothermal soils in Yellowstone National Park

USGS Publications Warehouse

Redman, R.S.; Litvintseva, A.; Sheehan, K.B.; Henson, J.M.; Rodriguez, R.J.

1999-01-01

Geothermal soils near Amphitheater Springs in Yellowstone National Park were characterized by high temperatures (up to 70??C), high heavy metal content, low pH values (down to pH 2.7), sparse vegetation, and limited organic carbon. From these soils we cultured 16 fungal species. Two of these species were thermophilic, and six were thermotolerant. We cultured only three of these species from nearby cool (0 to 22??C) soils. Transect studies revealed that higher numbers of CFUs occurred in and below the root zone of the perennial plant Dichanthelium lanuginosum (hot springs panic grass). The dynamics of fungal CFUs in geothermal soil and nearby nongeothermal soil were investigated for 12 months by examining soil cores and in situ mesocosms. For all of the fungal species studied, the temperature of the soil from which the organisms were cultured corresponded with their optimum axenic growth temperature.

Fungi from Geothermal Soils in Yellowstone National Park

PubMed Central

Redman, Regina S.; Litvintseva, Anastassia; Sheehan, Kathy B.; Henson, Joan M.; Rodriguez, Rusty J.

1999-01-01

Geothermal soils near Amphitheater Springs in Yellowstone National Park were characterized by high temperatures (up to 70°C), high heavy metal content, low pH values (down to pH 2.7), sparse vegetation, and limited organic carbon. From these soils we cultured 16 fungal species. Two of these species were thermophilic, and six were thermotolerant. We cultured only three of these species from nearby cool (0 to 22°C) soils. Transect studies revealed that higher numbers of CFUs occurred in and below the root zone of the perennial plant Dichanthelium lanuginosum (hot springs panic grass). The dynamics of fungal CFUs in geothermal soil and nearby nongeothermal soil were investigated for 12 months by examining soil cores and in situ mesocosms. For all of the fungal species studied, the temperature of the soil from which the organisms were cultured corresponded with their optimum axenic growth temperature. PMID:10583964

Characterization of labile organic carbon in coastal wetland soils of the Mississippi River deltaic plain: relationships to carbon functionalities.

PubMed

Dodla, Syam K; Wang, Jim J; Delaune, Ronald D

2012-10-01

Adequate characterization of labile organic carbon (LOC) is essential to the understanding of C cycling in soil. There has been very little evaluation about the nature of LOC characterizations in coastal wetlands, where soils are constantly influenced by different redox fluctuations and salt water intrusions. In this study, we characterized and compared LOC fractions in coastal wetland soils of the Mississippi River deltaic plain using four different methods including 1) aerobically mineralizable C (AMC), 2) cold water extractable C (CWEC), 3) hot water extractable C (HWEC), and 4) salt extractable C (SEC), as well as acid hydrolysable C (AHC) which includes both labile and slowly degradable organic C. Molecular organic C functional groups of these wetland soils were characterized by (13)C solid-state nuclear magnetic resonance (NMR). The LOC and AHC increased with soil organic C (SOC) regardless of wetland soil type. The LOC estimates by four different methods were positively and significantly linearly related to each other (R(2)=0.62-0.84) and with AHC (R(2)=0.47-0.71). The various LOC fractions accounted for ≤4.3% of SOC whereas AHC fraction represented 16-49% of SOC. AMC was influenced positively by O/N-alkyl and carboxyl C but negatively by alkyl C, whereas CWEC and SEC fractions were influenced only positively by carboxyl C but negatively by alkyl C in SOC. On the other hand, HWEC fraction was found to be only influenced positively by carbonyl C, and AHC positively by O/N-alkyl and alkyl C but negatively by aromatic C groups in SOC. Overall these relations suggested different contributions of various molecular organic C moieties to LOC in these wetlands from those often found for upland soils. The presence of more than 50% non-acid hydrolysable C suggested the dominance of relatively stable SOC pool that would be sequestered in these Mississippi River deltaic plain coastal wetland soils. The results have important implications to the understanding of the

Airflow dispersion in unsaturated soil.

PubMed

Gidda, T; Cann, D; Stiver, W H; Zytner, R G

2006-01-05

Dispersion data is abundant for water flow in the saturated zone but is lacking for airflow in unsaturated soil. However, for remediation processes such as soil vapour extraction, characterization of airflow dispersion is necessary for improved modelling and prediction capabilities. Accordingly, gas-phase tracer experiments were conducted in five soils ranging from uniform sand to clay at air-dried and wetted conditions. The disturbed soils were placed in one-dimensional stainless steel columns, with sulfur hexafluoride used as the inert tracer. The tested interstitial velocities were typical of those present in the vicinity of a soil vapour extraction well, while wetting varied according to the water-holding capacity of the soils. Results gave dispersivities that varied between 0.42 and 2.6 cm, which are typical of values in the literature. In air-dried soils, dispersion was found to increase with the pore size variability of the soil. For wetted soils, particle shape was an important factor at low water contents, while at high water contents, the proportion of macroporous space filled with water was important. The relative importance of diffusion decreased with increasing interstitial velocity and water content and was, in general, found to be minor compared to mechanical mixing across all conditions studied.

Characterization of free nitrogen fixing bacteria of the genus Azotobacter in organic vegetable-grown Colombian soils

PubMed Central

Jiménez, Diego Javier; Montaña, José Salvador; Martínez, María Mercedes

2011-01-01

With the purpose of isolating and characterizing free nitrogen fixing bacteria (FNFB) of the genus Azotobacter, soil samples were collected randomly from different vegetable organic cultures with neutral pH in different zones of Boyacá-Colombia. Isolations were done in selective free nitrogen Ashby-Sucrose agar obtaining a recovery of 40%. Twenty four isolates were evaluated for colony and cellular morphology, pigment production and metabolic activities. Molecular characterization was carried out using amplified ribosomal DNA restriction analysis (ARDRA). After digestion of 16S rDNA Y1-Y3 PCR products (1487pb) with AluI, HpaII and RsaI endonucleases, a polymorphism of 16% was obtained. Cluster analysis showed three main groups based on DNA fingerprints. Comparison between ribotypes generated by isolates and in silico restriction of 16S rDNA partial sequences with same restriction enzymes was done with Gen Workbench v.2.2.4 software. Nevertheless, Y1-Y2 PCR products were analysed using BLASTn. Isolate C5T from tomato (Lycopersicon esculentum) grown soils presented the same in silico restriction patterns with A. chroococcum (AY353708) and 99% of similarity with the same sequence. Isolate C5CO from cauliflower (Brassica oleracea var. botrytis) grown soils showed black pigmentation in Ashby-Benzoate agar and high similarity (91%) with A. nigricans (AB175651) sequence. In this work we demonstrated the utility of molecular techniques and bioinformatics tools as a support to conventional techniques in characterization of the genus Azotobacter from vegetable-grown soils. PMID:24031700

Soil Eroison, T Values, and Sustainability: A Review and Exercise.

ERIC Educational Resources Information Center

Beach, Timothy; Gersmehl, Philip

1993-01-01

Reviews issues related to soil erosion and soil loss tolerance in the United States. Describes an instructional plan in which students estimate soil loses in three geographical regions using the Universal Soil Loss Equation (USLE). Recommends integrating the geography of soil erosion with broader conceptual questions in physical geography. (CFR)

Soil type-depending effect of paddy management: composition and distribution of soil organic matter

NASA Astrophysics Data System (ADS)

Urbanski, Livia; Kölbl, Angelika; Lehndorff, Eva; Houtermans, Miriam; Schad, Peter; Zhang, Gang-Lin; Rahayu Utami, Sri; Kögel-Knabner, Ingrid

2016-04-01

Paddy soil management is assumed to promote soil organic matter accumulation and specifically lignin caused by the resistance of the aromatic lignin structure against biodegradation under anaerobic conditions during inundation of paddy fields. The present study investigates the effect of paddy soil management on soil organic matter composition compared to agricultural soils which are not used for rice production (non-paddy soils). A variety of major soil types, were chosen in Indonesia (Java), including Alisol, Andosol and Vertisol sites (humid tropical climate of Java, Indonesia) and in China Alisol sites (humid subtropical climate, Nanjing). This soils are typically used for rice cultivation and represent a large range of soil properties to be expected in Asian paddy fields. All topsoils were analysed for their soil organic matter composition by solid-state 13C nuclear magnetic resonance spectroscopy and lignin-derived phenols by CuO oxidation method. The soil organic matter composition, revealed by solid-state 13C nuclear magnetic resonance, was similar for the above named different parent soil types (non-paddy soils) and was also not affected by the specific paddy soil management. The contribution of lignin-related carbon groups to total SOM was similar in the investigated paddy and non-paddy soils. A significant proportion of the total aromatic carbon in some paddy and non-paddy soils was attributed to the application of charcoal as a common management practise. The extraction of lignin-derived phenols revealed low VSC (vanillyl, syringyl, cinnamyl) values for all investigated soils, being typical for agricultural soils. An inherent accumulation of lignin-derived phenols due to paddy management was not found. Lignin-derived phenols seem to be soil type-dependent, shown by different VSC concentrations between the parent soil types. The specific paddy management only affects the lignin-derived phenols in Andosol-derived paddy soils which are characterized by

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.

Soil quality and soil degradation in agricultural loess soils in Central Europe - impacts of traditional small-scale and modernized large-scale agriculture

NASA Astrophysics Data System (ADS)

Schneider, Christian

2017-04-01

The study analyzes the impact of different farming systems on soil quality and soil degradation in European loess landscapes. The analyses are based on geo-chemical soil properties, landscape metrics and geomorphological indicators. The German Middle Saxonian Loess Region represents loess landscapes whose ecological functions were shaped by land consolidation measures resulting in large-scale high-input farming systems. The Polish Proszowice Plateau is still characterized by a traditional small-scale peasant agriculture. The research areas were analyzed on different scale levels combining GIS, field, and laboratory methods. A digital terrain classification was used to identify representative catchment basins for detailed pedological studies which were focused on soil properties that responded to soil management within several years, like pH-value, total carbon (TC), total nitrogen (TN), inorganic carbon (IC), soil organic carbon (TOC=TC-IC), hot-water extractable carbon (HWC), hot-water extractable nitrogen (HWN), total phosphorus, plant-available phosphorus (P), plant-available potassium (K) and the potential cation exchange capacity (CEC). The study has shown that significant differences in major soil properties can be observed because of different fertilizer inputs and partly because of different cultivation techniques. Also the traditional system increases soil heterogeneity. Contrary to expectations the study has shown that the small-scale peasant farming system resulted in similar mean soil organic carbon and phosphorus contents like the industrialized high-input farming system. A further study could include investigations of the effects of soil amendments like herbicides and pesticide on soil degradation.

Estimating SPT-N Value Based on Soil Resistivity using Hybrid ANN-PSO Algorithm

NASA Astrophysics Data System (ADS)

Nur Asmawisham Alel, Mohd; Ruben Anak Upom, Mark; Asnida Abdullah, Rini; Hazreek Zainal Abidin, Mohd

2018-04-01

Standard Penetration Resistance (N value) is used in many empirical geotechnical engineering formulas. Meanwhile, soil resistivity is a measure of soil’s resistance to electrical flow. For a particular site, usually, only a limited N value data are available. In contrast, resistivity data can be obtained extensively. Moreover, previous studies showed evidence of a correlation between N value and resistivity value. Yet, no existing method is able to interpret resistivity data for estimation of N value. Thus, the aim is to develop a method for estimating N-value using resistivity data. This study proposes a hybrid Artificial Neural Network-Particle Swarm Optimization (ANN-PSO) method to estimate N value using resistivity data. Five different ANN-PSO models based on five boreholes were developed and analyzed. The performance metrics used were the coefficient of determination, R2 and mean absolute error, MAE. Analysis of result found that this method can estimate N value (R2 best=0.85 and MAEbest=0.54) given that the constraint, Δ {\\bar{l}}ref, is satisfied. The results suggest that ANN-PSO method can be used to estimate N value with good accuracy.

A mower detector to judge soil sorting

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

Bramlitt, E.T.; Johnson, N.R.

1995-12-31

Thermo Nuclear Services (TNS) has developed a mower detector as an inexpensive and fast means for deciding potential value of soil sorting for cleanup. It is a shielded detector box on wheels pushed over the ground (as a person mows grass) at 30 ft/min with gamma-ray counts recorded every 0.25 sec. It mirror images detection by the TNS transportable sorter system which conveys soil at 30 ft/min and toggles a gate to send soil on separate paths based on counts. The mower detector shows if contamination is variable and suitable for sorting, and by unique calibration sources, it indicates detectionmore » sensitivity. The mower detector has been used to characterize some soil at Department of Energy sites in New Jersey and South Carolina.« less

The impact of fog on soil moisture dynamics in the Namib Desert

NASA Astrophysics Data System (ADS)

Li, Bonan; Wang, Lixin; Kaseke, Kudzai F.; Vogt, Roland; Li, Lin; Seely, Mary K.

2018-03-01

Soil moisture is a crucial component supporting vegetation dynamics in drylands. Despite increasing attention on fog in dryland ecosystems, the statistical characterization of fog distribution and how fog affects soil moisture dynamics have not been seen in literature. To this end, daily fog records over two years (Dec 1, 2014-Nov 1, 2016) from three sites within the Namib Desert were used to characterize fog distribution. Two sites were located within the Gobabeb Research and Training Center vicinity, the gravel plains and the sand dunes. The third site was located at the gravel plains, Kleinberg. A subset of the fog data during rainless period was used to investigate the effect of fog on soil moisture. A stochastic modeling framework was used to simulate the effect of fog on soil moisture dynamics. Our results showed that fog distribution can be characterized by a Poisson process with two parameters (arrival rate λ and average depth α (mm)). Fog and soil moisture observations from eighty (Aug 19, 2015-Nov 6, 2015) rainless days indicated a moderate positive relationship between soil moisture and fog in the Gobabeb gravel plains, a weaker relationship in the Gobabeb sand dunes while no relationship was observed at the Kleinberg site. The modeling results suggested that mean and major peaks of soil moisture dynamics can be captured by the fog modeling. Our field observations demonstrated the effects of fog on soil moisture dynamics during rainless periods at some locations, which has important implications on soil biogeochemical processes. The statistical characterization and modeling of fog distribution are of great value to predict fog distribution and investigate the effects of potential changes in fog distribution on soil moisture dynamics.

Controlled release formulations of Atrazine and Mesotrione: characterization and sorption on soils

NASA Astrophysics Data System (ADS)

Pinheiro Dick, D.; Gomes de Ávila, L.; Benvenuti Leite, S.; Raffin Pohlmann, A.

2009-04-01

Atrazine is a widely used herbicide on corn and sugar cane plantations, which, along with soybeans, are the most productive crops in Brazil and are responsible for 36.5% of the annual national consumption of herbicides. Mesotrione is a new herbicide registered in the last years used for controlling weeds in corn plantations as a tentative substitution for atrazine. After its application in the field, reactions between the herbicide and chemical groups from the soil matrix surface occur, and this complexed form remains in the soil, representing a potential source for environmental contamination and also affecting its agronomic efficiency. Therefore, the application of herbicides associated to carrier systems may represent an alternative to mitigate the environmental impact caused by their intense usage, considering that the interaction between the soil matrix and the xenobiotic is reduced, and thus, diminishes the recommended dosis and reduces the environmental pollution. The objectives of this study are to evaluate the chemical and morphological characteristics of controlled release formulations of atrazine (ATZ) and of mesotrione (MES) and to investigate their sorptive behavior in three representative Brazilian soils. To assess the feasibility of using these associated systems, four formulations (SGATZ) containing different concentrations of atrazine and four formulations (SGMES) containing different levels of mesotrione (MES) were synthesized by the sol-gel method (SG), using tetraetil-ortho-silicate as precursor and NaF as catalyst. The formulations were characterized by elemental analysis, adsorption and desorption isotherms of nitrogen, thermal analysis (DSC), scanning electron microscopy (SEM) and infrared spectroscopy (FTIR). For comparison, samples of pure xerogel (SG), commercial MES (Callisto-Syngenta), pure ATZ (99% of active principle, Milênia), granulated ATZ (Gesaprim GrDA Syngenta) and dried commercial ATZ (Nortox 500 SC) were analyzed. The

Towards the Wetness Characterization of Soil Subsurface Using Fibre Optic Distributed Acoustic Sensing

NASA Astrophysics Data System (ADS)

Ciocca, F.; Bodet, L.; Simon, N.; Karaulanov, R.; Clarke, A.; Abesser, C.; Krause, S.; Chalari, A.; Mondanos, M.

2017-12-01

Active seismic methods combined with detectors deployed at the soil surface, such as vertical collinear geophones, have revealed great potential for hydrogeophysical characterization of the soil vadose zone. In particular, recent findings have highlighted a clear dependence of both P-waves arrival times and surface-wave dispersion on the local degree of soil saturation, visible at laboratory as well as at field scale. In this study, we investigate the sensitivity of a fibre optic Distributed Acoustic Sensor (DAS) to different soil saturation. In vertical seismic applications, DAS have proven to offer equal and often better performance compared to the geophones, with the advantage that a fibre optic cable, whose length can reach 40 km, replaces the array of geophones as sensing element. We present the response to active seismic tests of 20 m of fibre optic cable buried in a poorly permeable bare soil. Tests were conducted in different moments of the year, with saturation monitored by means of independent dielectric probes. Body-wave travel times as well as surface-wave dispersion are compared. Finally, we discuss the possibility to determine a site-specific relation between the Poisson ratio and the soil saturation. This research has been performed in the framework of the British National Environmental Research Council (NERC) funded Distributed intelligent Heat Pulse System (DiHPS) project and of the Marie Curie H2020 Research and Innovation Staff Exchange (RISE) consortium Hi-Freq.

Use of a watershed model to characterize the fate and transport of fluometuron, a soil-applied cotton herbicide, in surface water

USGS Publications Warehouse

Coupe, R.H.

2007-01-01

The Soil and Water Assessment Tool (SWAT) was used to characterize the fate and transport of fluometuron (a herbicide used on cotton) in the Bogue Phalia Basin in northwestern Mississippi, USA. SWAT is a basin-scale watershed model, able to simulate hydrological, chemical, and sediment transport processes. After adjustments to a few parameters (specifically the SURLAG variable, the runoff curve number, Manning's N for overland flow, soil available water capacity, and the base-flow alpha factor) the SWAT model fit the observed streamflow well (the Coefficient of Efficiency and R2 were greater than 60). The results from comparing observed fluometuron concentrations with simulated concentrations were reasonable. The simulated concentrations (which were daily averages) followed the pattern of observed concentrations (instantaneous values) closely, but could be off in magnitude at times. Further calibration might have improved the fit, but given the uncertainties in the input data, it was not clear that any improvement would be due to a better understanding of the input variables. ?? 2007 Taylor & Francis.

Relationships between nuclear magnetic resonance parameters used to characterize weathering spilled oil and soil toxicity in central Patagonia.

PubMed

Ríos, Stella Maris; Barquin, Mercedes; Katusich, Ofelia; Nudelman, Norma

2014-01-01

Oil spill in the Central Patagonian zone was studied to evaluate if any relationship exists between the parameters used to characterize weathering spilled oil and soil toxicity for two plant species and to evaluate if the phytotoxicity to local species would be a good index for the soil contamination. Nuclear magnetic resonance (NMR) structural indexes and column chromatography compositional indexes were determined to characterize the oil spill in the soil samples. Bioassays were also carried out using Lactuca sativa L (reference) and Atriplex lampa (native species) as test organisms. Measurements of the total petroleum hydrocarbon (TPH) and the electrical conductivity (EC) of the soil were carried out to evaluate the effect on the bioassays. The principal components analysis of the parameters determined by NMR, compositional indexes, EC, TPH, and toxicology data shows that the first three principal components accounted for the 78% of the total variance (40%, 25%, and 13% for the first, second, and third PC, respectively). A good agreement was found between information obtained by compositional indexes and NMR structural indexes. Soil toxicity increases with the increase of EC and TPH. Other factors, such as, the presence of branched and aromatic hydrocarbons is also significant. The statistical evaluation showed that the Euclidean distances (3D) between the background and each one of the samples might be a better indicator of the soil contamination, compared with chemical criterion of TPH.

Influence of management history and landscape variables on soil organic carbon and soil redistribution

USGS Publications Warehouse

Venteris, E.R.; McCarty, G.W.; Ritchie, J.C.; Gish, T.

2004-01-01

Controlled studies to investigate the interaction between crop growth, soil properties, hydrology, and management practices are common in agronomy. These sites (much as with real world farmland) often have complex management histories and topographic variability that must be considered. In 1993 an interdisiplinary study was started for a 20-ha site in Beltsville, MD. Soil cores (271) were collected in 1999 in a 30-m grid (with 5-m nesting) and analyzed as part of the site characterization. Soil organic carbon (SOC) and 137Cesium (137Cs) were measured. Analysis of aerial photography from 1992 and of farm management records revealed that part of the site had been maintained as a swine pasture and the other portion as cropped land. Soil properties, particularly soil redistribution and SOC, show large differences in mean values between the two areas. Mass C is 0.8 kg m -2 greater in the pasture area than in the cropped portion. The pasture area is primarily a deposition site, whereas the crop area is dominated by erosion. Management influence is suggested, but topographic variability confounds interpretation. Soil organic carbon is spatially structured, with a regionalized variable of 120 m. 137Cs activity lacks spatial structure, suggesting disturbance of the profile by animal activity and past structures such as swine shelters and roads. Neither SOC nor 137Cs were strongly correlated to terrain parameters, crop yields, or a seasonal soil moisture index predicted from crop yields. SOC and 137Cs were weakly correlated (r2 ???0.2, F-test P-value 0.001), suggesting that soil transport controls, in part, SOC distribution. The study illustrates the importance of past site history when interpreting the landscape distribution of soil properties, especially those strongly influenced by human activity. Confounding variables, complex soil hydrology, and incomplete documentation of land use history make definitive interpretations of the processes behind the spatial distributions

Pre-incubation in soil improves the nitrogen fertiliser value of hair waste.

PubMed

Malepfane, N M; Muchaonyerwa, P

2018-01-25

Global generation of human hair waste and its disposal at landfills could contribute to the leaching of nitrates into ground water. High concentrations of nitrogen (N) and other elements suggest that the waste could be a source of plant nutrients and differences in ethnic hair types could affect nutrient release and fertiliser value. The objective of this study was to determine the effects of hair type, as an N source, and pre-incubation time on dry-matter yield, nutrient uptake by spinach (Spinacia oleracea L.) and residual soil nutrients. Salons in Pietermaritzburg provided bulk African and Caucasian hair waste, without distinguishing age, sex, health status or livelihood of the individuals. The hair waste was analysed for elemental composition. A pot experiment was set up under glasshouse conditions. The hair waste was incorporated (400 kg N ha -1 ) into a loamy oxisol and pre-incubated for 0, 28, 56 and 84 days before planting spinach. Potassium (K) and phosphorus (P) were corrected to the same level for all treatments. Spinach seedlings were then cultivated for 6 weeks. Shoot dry-matter and the uptake of all nutrients, except P, were increased by the pre-incubation of hair. African hair pre-incubated for 28 days resulted in greater dry-matter, N, K, Mn and S uptake than Caucasian hair. Increasing pre-incubation resulted in a decline in the residual soil pH and exchangeable K. The findings suggested that pre-incubation improves the N fertiliser value of hair and that African hair has greater value than Caucasian hair when pre-incubated for a short period.

Linking Carbon Flux Dynamics and Soil Structure in Dryland Soils

NASA Astrophysics Data System (ADS)

DeCarlo, K. F.; Caylor, K. K.

2016-12-01

Biological sources in the form of microbes and plants play a fundamental role in determining the magnitude of carbon flux. However, the geophysical structure of the soil (which the carbon must pass through before entering the atmosphere) often serves as a constraining entity, which has the potential to serve as instigators or mitigators of those carbon and hydrologic flux processes. We characterized soil carbon dynamics in three dryland soil systems: bioturbated soils, biocompacted soils, and undisturbed soils. Carbon fluxes were characterized using a closed-system respiration chamber, with CO2 concentration differences measured using an infrared gas analyzer (IRGA). Structure of the soil systems, with a focus on the macro-crack structure, were characterized using a combined resin-casting/X-ray imaging technique. Results show fundamental differences in carbon dynamics between the different soil systems/structures: control soils have gaussian distributions of carbon flux that decrease with progressive drying of the soil, while biocompacted soils exhibit exponentially distributed fluxes that do not regularly decrease with increased drying of the soil. Bioturbated soils also exhibit an exponential distribution of carbon flux, though at a much higher magnitude. These differences are evaluated in the context of the underlying soil structure: while the control soils exhibit a shallow and narrow crack structure, the biocompacted soils exhibit a "systematic" crack network with moderate cracking intensity and large depth. The deep crack networks of the biocompacted soils may serve to physically enhance an otherwise weak source of carbon via advection and/or convection, inducing fluxes that are equal or greater than an otherwise carbon-rich soil. The bioturbated soils exhibit a "surficial" crack network that is shallow but extensive, but additionally have deep holes known to convectively vent carbon, which may explain their periodically large carbon fluxes. Our results

DEVELOPING ECOLOGICAL SOIL SCREENING LEVELS: BENCHMARK VALUES FOR SOIL INVERTEBRATES, PLANTS, AND MICROBIAL FUNCTIONS

EPA Science Inventory

Soils are repositories for environmental contaminants (COCs) in terrestrial ecosystems. Time, effort, and money repeatedly are invested in literature-based evaluations of potential soil-ecotoxicity...

Adsorption coefficients for TNT on soil and clay minerals

NASA Astrophysics Data System (ADS)

Rivera, Rosángela; Pabón, Julissa; Pérez, Omarie; Muñoz, Miguel A.; Mina, Nairmen

2007-04-01

To understand the fate and transport mechanisms of TNT from buried landmines is it essential to determine the adsorption process of TNT on soil and clay minerals. In this research, soil samples from horizons Ap and A from Jobos Series at Isabela, Puerto Rico were studied. The clay fractions were separated from the other soil components by centrifugation. Using the hydrometer method the particle size distribution for the soil horizons was obtained. Physical and chemical characterization studies such as cation exchange capacity (CEC), surface area, percent of organic matter and pH were performed for the soil and clay samples. A complete mineralogical characterization of clay fractions using X-ray diffraction analysis reveals the presence of kaolinite, goethite, hematite, gibbsite and quartz. In order to obtain adsorption coefficients (K d values) for the TNT-soil and TNT-clay interactions high performance liquid chromatography (HPLC) was used. The adsorption process for TNT-soil was described by the Langmuir model. A higher adsorption was observed in the Ap horizon. The Freundlich model described the adsorption process for TNT-clay interactions. The affinity and relative adsorption capacity of the clay for TNT were higher in the A horizon. These results suggest that adsorption by soil organic matter predominates over adsorption on clay minerals when significant soil organic matter content is present. It was found that, properties like cation exchange capacity and surface area are important factors in the adsorption of clayey soils.

Is received dose from ingested soil independent of soil PAH concentrations?-Animal model results.

PubMed

Peters, Rachel E; James, Kyle; Cave, Mark; Wickstrom, Mark; Siciliano, Steven D

2016-09-01

Polycyclic aromatic hydrocarbon (PAH) bioavailability from ingested soils will vary between soils; however, the nature of this variation is not well characterized. A juvenile swine model was used to link external exposure to internal benzo[a]pyrene (BaP) and anthracene exposure following oral PAH ingestion of 27 different impacted site soils, soots, or spiked artificial soils. Internal exposure of BaP and anthracene, represented by area under the plasma-time curve, did not relate to soil concentration in impacted site soils, but did relate in spiked artificial soil. Point of departure modeling identified soil PAH concentrations greater than 1900 mg kg(-1) as the point where area under the curve becomes proportional to external dose. A BaP internal exposure below 1900 mg kg(-1) had an upper 95% confidence interval estimate of 33% of external exposure. Weak relationships between soil:simulated gastrointestinal fluid PAH partitioning and area under the curve values suggest that differences in internal PAH exposure between soils may not be dominated by differences in PAH partitioning. The data seem to best support exposure assessment assuming constant internal PAH exposure below soil concentrations of 1900 mg kg(-1) . However, because constant internal exposure would challenge several existing paradigms, a bioavailability estimate of 33% of the external exposure is suggested as a likely workable solution. Environ Toxicol Chem 2016;35:2261-2269. © 2016 SETAC. © 2016 SETAC.

Incorporation of satellite remote sensing pan-sharpened imagery into digital soil prediction and mapping models to characterize soil property variability in small agricultural fields

NASA Astrophysics Data System (ADS)

Xu, Yiming; Smith, Scot E.; Grunwald, Sabine; Abd-Elrahman, Amr; Wani, Suhas P.

2017-01-01

Soil prediction models based on spectral indices from some multispectral images are too coarse to characterize spatial pattern of soil properties in small and heterogeneous agricultural lands. Image pan-sharpening has seldom been utilized in Digital Soil Mapping research before. This research aimed to analyze the effects of pan-sharpened (PAN) remote sensing spectral indices on soil prediction models in smallholder farm settings. This research fused the panchromatic band and multispectral (MS) bands of WorldView-2, GeoEye-1, and Landsat 8 images in a village in Southern India by Brovey, Gram-Schmidt and Intensity-Hue-Saturation methods. Random Forest was utilized to develop soil total nitrogen (TN) and soil exchangeable potassium (Kex) prediction models by incorporating multiple spectral indices from the PAN and MS images. Overall, our results showed that PAN remote sensing spectral indices have similar spectral characteristics with soil TN and Kex as MS remote sensing spectral indices. There is no soil prediction model incorporating the specific type of pan-sharpened spectral indices always had the strongest prediction capability of soil TN and Kex. The incorporation of pan-sharpened remote sensing spectral data not only increased the spatial resolution of the soil prediction maps, but also enhanced the prediction accuracy of soil prediction models. Small farms with limited footprint, fragmented ownership and diverse crop cycle should benefit greatly from the pan-sharpened high spatial resolution imagery for soil property mapping. Our results show that multiple high and medium resolution images can be used to map soil properties suggesting the possibility of an improvement in the maps' update frequency. Additionally, the results should benefit the large agricultural community through the reduction of routine soil sampling cost and improved prediction accuracy.

Characterizing Martian Soils: Correlating Orbital Observations with Chemistry and Mineralogy from Landed Missions

NASA Astrophysics Data System (ADS)

Bishop, J. L.

2010-12-01

Great advances have been achieved recently in our understanding of the surface of Mars at global scales from orbital missions and at local scales from landed missions. This presentation seeks to provide links between the chemistry and mineralogy observed by landed missions with remote detections of minerals from orbit. Spectral data from CRISM, OMEGA and TES characterize a mostly basaltic planet with some outcrops of hematite, clays, sulfates and carbonates at the surface. Recent alteration of these rocks to form soils has likely been dominated by physical processes; however, martian soils probably also contain relicts of early alteration involving aqueous processes. Clays, hydroxides, sulfates, carbonates and perchlorates are examples of surface components that may have formed early in the planet’s history in the presence of liquid water. Some of these minerals have not been detected in the soil, but all have likely contributed to the current soil composition. The grain size, shape, chemistry, mineralogy, and magnetic properties of Martian soils are similar to altered volcanic ash found at many analog sites on Earth. Reflectance and emission spectra of some of these analog soils are consistent with the basic soil spectral properties observed from orbit. The cemented soil units observed by rovers may have formed through interaction of the soil grains with salts, clays, and hydroxides. Lab experiments have shown that cementing of analog grains darkens the VN reflectance, which could explain the low reflectance of Martian soils compared to analog sites. Reflectance spectra of an analog soil mixture containing altered ash and sulfate are shown in Figure 1. A pellet was made by adding water and allowing the sample to dry in air. Finally, the pellet was crushed and ground again to <125 µm. Both the dried pellet spectrum and the crushed pellet spectrum are darker than the original spectrum of the same composition. Erosion and weathering are likely the dominant

Mapping Soil pH Buffering Capacity of Selected Fields

NASA Technical Reports Server (NTRS)

Weaver, A. R.; Kissel, D. E.; Chen, F.; West, L. T.; Adkins, W.; Rickman, D.; Luvall, J. C.

2003-01-01

Soil pH buffering capacity, since it varies spatially within crop production fields, may be used to define sampling zones to assess lime requirement, or for modeling changes in soil pH when acid forming fertilizers or manures are added to a field. Our objective was to develop a procedure to map this soil property. One hundred thirty six soil samples (0 to 15 cm depth) from three Georgia Coastal Plain fields were titrated with calcium hydroxide to characterize differences in pH buffering capacity of the soils. Since the relationship between soil pH and added calcium hydroxide was approximately linear for all samples up to pH 6.5, the slope values of these linear relationships for all soils were regressed on the organic C and clay contents of the 136 soil samples using multiple linear regression. The equation that fit the data best was b (slope of pH vs. lime added) = 0.00029 - 0.00003 * % clay + 0.00135 * % O/C, r(exp 2) = 0.68. This equation was applied within geographic information system (GIS) software to create maps of soil pH buffering capacity for the three fields. When the mapped values of the pH buffering capacity were compared with measured values for a total of 18 locations in the three fields, there was good general agreement. A regression of directly measured pH buffering capacities on mapped pH buffering capacities at the field locations for these samples gave an r(exp 2) of 0.88 with a slope of 1.04 for a group of soils that varied approximately tenfold in their pH buffering capacities.

Algological and Mycological Characterization of Soils under Pine and Birch Forests in the Pasvik Reserve

NASA Astrophysics Data System (ADS)

Korneikova, M. V.; Redkina, V. V.; Shalygina, R. R.

2018-02-01

The structure of algological and mycological complexes in Al-Fe-humus podzols (Albic Podzols) under pine and birch forests of the Pasvik Reserve is characterized. The number of micromycetes is higher in more acid soils of the pine forest, while the species diversity is greater under the birch forest. The genus Penicillium includes the largest number of species. The greatest abundance and occurrence frequency are typical for Penicillium spinulosum, P. glabrum, and Trichoderma viride in pine forest and for Umbelopsis isabellina, Mucor sp., Mortierella alpina, P. glabrum, Aspergillus ustus, Trichoderma viride, and T. koningii in birch forest. Cyanobacteria-algal cenoses of the investigated soils are predominated by green algae. Soils under birch forest are distinguished by a greater diversity of algal groups due to the presence of diatoms and xanthophytes. Species of frequent occurrence are represented by Pseudococcomyxa simplex and Parietochloris alveolaris in soils of the pine forest and by Tetracystis cf. aplanospora, Halochlorella rubescens, Pseudococcomyxa simplex, Fottea stichococcoides, Klebsormidium flaccidum, Hantzschia amphioxys, Microcoleus vaginatus, and Aphanocapsa sp. in soils under birch forest

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...

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

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

Moment Analysis Characterizing Water Flow in Repellent Soils from On- and Sub-Surface Point Sources

NASA Astrophysics Data System (ADS)

Xiong, Yunwu; Furman, Alex; Wallach, Rony

2010-05-01

Water repellency has a significant impact on water flow patterns in the soil profile. Flow tends to become unstable in such soils, which affects the water availability to plants and subsurface hydrology. In this paper, water flow in repellent soils was experimentally studied using the light reflection method. The transient 2D moisture profiles were monitored by CCD camera for tested soils packed in a transparent flow chamber. Water infiltration experiments and subsequent redistribution from on-surface and subsurface point sources with different flow rates were conducted for two soils of different repellency degrees as well as for wettable soil. We used spatio-statistical analysis (moments) to characterize the flow patterns. The zeroth moment is related to the total volume of water inside the moisture plume, and the first and second moments are affinitive to the center of mass and spatial variances of the moisture plume, respectively. The experimental results demonstrate that both the general shape and size of the wetting plume and the moisture distribution within the plume for the repellent soils are significantly different from that for the wettable soil. The wetting plume of the repellent soils is smaller, narrower, and longer (finger-like) than that of the wettable soil compared with that for the wettable soil that tended to roundness. Compared to the wettable soil, where the soil water content decreases radially from the source, moisture content for the water-repellent soils is higher, relatively uniform horizontally and gradually increases with depth (saturation overshoot), indicating that flow tends to become unstable. Ellipses, defined around the mass center and whose semi-axes represented a particular number of spatial variances, were successfully used to simulate the spatial and temporal variation of the moisture distribution in the soil profiles. Cumulative probability functions were defined for the water enclosed in these ellipses. Practically identical

Estimation of factors from natural and anthropogenic radioactivity present in the surface soil and comparison with DCF values.

PubMed

Ranade, A K; Pandey, M; Datta, D

2013-01-01

A study was conducted to evaluate the absorbed rate coefficient of (238)U, (232)Th, (40)K and (137)Cs present in soil. A total of 31 soil samples and the corresponding terrestrial dose rates at 1 m from different locations were taken around the Anushaktinagar region, where the litho-logy is dominated by red soil. A linear regression model was developed for the estimation of these factors. The estimated coefficients (nGy h(-1) Bq(-1) kg(-1)) were 0.454, 0.586, 0.035 and 0.392, respectively. The factors calculated were in good agreement with the literature values.

Study of microarthopod communities to assess soil quality in different managed vineyards

NASA Astrophysics Data System (ADS)

Gagnarli, E.; Goggioli, D.; Tarchi, F.; Guidi, S.; Nannelli, R.; Vignozzi, N.; Valboa, G.; Lottero, M. R.; Corino, L.; Simoni, S.

2015-01-01

Land use influences the abundance and diversity of soil arthropods. The evaluation of the impact of different management strategies on soil quality is increasingly requested. The determination of communities' structures of edaphic fauna can represent an efficient tool. In this study, in some vineyards in Piedmont (Italy), the effects of two different management systems, organic and integrated pest management (IPM), on soil biota were evaluated. As microarthropods living in soil surface are an important component of soil ecosystem interacting with all the other system components, a multi disciplinary approach was adopted by characterizing also some soil physical and chemical characteristics (soil texture, soil pH, total organic carbon, total nitrogen, calcium carbonate). Soil samplings were carried out on Winter 2011 and Spring 2012. All specimens were counted and determined up to the order level. The biological quality of the soil was defined through the determination of ecological indices, such as QBS-ar, species richness and indices of Shannon-Weaver, Pielou, Margalef and Simpson. The mesofauna abundance was affected by both the type of management and the soil texture. The analysis of microarthropod communities by QBS-ar showed higher values in organic than in IPM managed vineyards; in particular, the values registered in organic vineyards were similar to those characteristic of preserved soils.

Use of USLE/GIS methodology for predicting soil loss in a semiarid agricultural watershed.

PubMed

Erdogan, Emrah H; Erpul, Günay; Bayramin, Ilhami

2007-08-01

The Universal Soil Loss Equation (USLE) is an erosion model to estimate average soil loss that would generally result from splash, sheet, and rill erosion from agricultural plots. Recently, use of USLE has been extended as a useful tool predicting soil losses and planning control practices in agricultural watersheds by the effective integration of the GIS-based procedures to estimate the factor values in a grid cell basis. This study was performed in the Kazan Watershed located in the central Anatolia, Turkey, to predict soil erosion risk by the USLE/GIS methodology for planning conservation measures in the site. Rain erosivity (R), soil erodibility (K), and cover management factor (C) values of the model were calculated from erosivity map, soil map, and land use map of Turkey, respectively. R values were site-specifically corrected using DEM and climatic data. The topographical and hydrological effects on the soil loss were characterized by LS factor evaluated by the flow accumulation tool using DEM and watershed delineation techniques. From resulting soil loss map of the watershed, the magnitude of the soil erosion was estimated in terms of the different soil units and land uses and the most erosion-prone areas where irreversible soil losses occurred were reasonably located in the Kazan watershed. This could be very useful for deciding restoration practices to control the soil erosion of the sites to be severely influenced.

Effects of Salt Accumulation in Soil by Evaporation on Unsaturated Soil Hydraulic Properties

NASA Astrophysics Data System (ADS)

Liu, Y.; Liu, Q.

2017-12-01

Soil salinization is one type of soil degradation caused by saline groundwater evaporation. Salt accumulation in the soil will change the pore structure of soil, which should change the unsaturated soil hydraulic properties including the soil water characteristic curve (SWCC). To investigate the effect of salt accumulation on the SWCC and find the best suitable SWCC model to characterize the relationship of soil moisture and soil matrix potential, we have conducted laboratory SWCC experiments with the soil columns saturated by NaCl solution with different concentration (deionized water, 3 g/L, 15 g/L, 50 g/L, 100 g/L and 200 g/L). As the concentration of initial solution increases, the matrix potential corresponding to the same moisture increases. As the water was evaporated, the salt would precipitate in soil continuously, which would decrease the porosity of soils and increase the negative pressure of soils. With higher initial concentration, the more salt accumulation caused the more residual water content in the soils. For van Genuchten-Mualem model, the residual water contents θr were 0.0159, 0.0181, 0.0182, 0.0328, 0.0312, 0.0723, 0.0864 in the columns initially saturated by deionized water, 3 g/L, 15 g/L, 50 g/L, 100 g/L and 200 g/L, respectively. The van Genuchten-Mualem model, Fredlund-Xing model, Gardern model, Mckee-Bumb model and Brooks-Corey model were fitted by MATLAB with the experiments data, and the fitted coefficients were compared. The Fredlund-Xing model has the best fitting coefficients and the calculated value was consistent with the observed data.

Soil structure characterized using computed tomographic images

Treesearch

Zhanqi Cheng; Stephen H. Anderson; Clark J. Gantzer; J. W. Van Sambeek

2003-01-01

Fractal analysis of soil structure is a relatively new method for quantifying the effects of management systems on soil properties and quality. The objective of this work was to explore several methods of studying images to describe and quantify structure of soils under forest management. This research uses computed tomography and a topological method called Multiple...

Cadmium background concentrations to establish reference quality values for soils of São Paulo State, Brazil.

PubMed

de Oliveira, Vinicius Henrique; de Abreu, Cleide Aparecida; Coelho, Ricardo Marques; Melo, Leônidas Carrijo Azevedo

2014-03-01

Proper assessment of soil cadmium (Cd) concentrations is essential to establish legislative limits. The present study aimed to assess background Cd concentrations in soils from the state of São Paulo, Brazil, and to correlate such concentrations with several soil attributes. The topsoil samples (n = 191) were assessed for total Cd contents and for other metals using the USEPA 3051A method. The background concentration was determined according to the third quartile (75th). Principal component analysis, Spearman correlation, and multiple regressions between Cd contents and other soil attributes (pH, cation exchange capacity (CEC), clay content, sum of bases, organic matter, and total Fe, Al, Zn, and Pb levels) were performed. The mean Cd concentration of all 191 samples was 0.4 mg kg(-1), and the background concentration was 0.5 mg kg(-1). After the samples were grouped by parent material (rock origin) and soil type, the background Cd content varied, i.e., soils from igneous, metamorphic, and sedimentary rocks harbored 1.5, 0.4, and 0.2 mg kg(-1) of Cd, respectively. The background Cd content in Oxisols (0.8 mg kg(-1)) was higher than in Ultisols (0.3 mg kg(-1)). Multiple regression demonstrated that Fe was primarily attributed to the natural Cd contents in the soils (R (2) = 0.79). Instead of a single Cd background concentration value representing all São Paulo soils, we propose that the concentrations should be specific for at least Oxisols and Ultisols, which are the primary soil types.

Sorption Equilibria of Vapor Phase Organic Pollutants on Unsaturated Soils and Soil Minerals

DTIC Science & Technology

1990-04-01

Sorbent Characterization .. ........ .......... 6 a. Description of Inorganic Solids and Soils. .... ........ 6 b. Moisture Content...compounds (TCE and toluene) is compared for a cored depth profile obtained from an unsaturated soil and for simulated profiles using inorganic solids. The...Sorbent Characterization a. Description of Inorganic Solids and Soils Inorganic solids were used for initial sorption studies to develop experimental

Aggregating available soil water holding capacity data for crop yield models

NASA Technical Reports Server (NTRS)

Seubert, C. E.; Daughtry, C. S. T.; Holt, D. A.; Baumgardner, M. F.

1984-01-01

The total amount of water available to plants that is held against gravity in a soil is usually estimated as the amount present at -0.03 MPa average water potential minus the amount present at -1.5 MPa water potential. This value, designated available water-holding capacity (AWHC), is a very important soil characteristic that is strongly and positively correlated to the inherent productivity of soils. In various applications, including assessing soil moisture status over large areas, it is necessary to group soil types or series as to their productivity. Current methods to classify AWHC of soils consider only total capacity of soil profiles and thus may group together soils which differ greatly in AWHC as a function of depth in the profile. A general approach for evaluating quantitatively the multidimensional nature of AWHC in soils is described. Data for 902 soil profiles, representing 184 soil series, in Indiana were obtained from the Soil Characterization Laboratory at Purdue University. The AWHC for each of ten 150-mm layers in each soil was established, based on soil texture and parent material. A multivariate clustering procedure was used to classify each soil profile into one of 4, 8, or 12 classes based upon ten-dimensional AWHC values. The optimum number of classes depends on the range of AWHC in the population of oil profiles analyzed and on the sensitivity of a crop to differences in distribution of water within the soil profile.

Soil erosion at agricultural land in Moravia loess region estimated by using magnetic properties

NASA Astrophysics Data System (ADS)

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

2014-05-01

A detailed field study on a small test site of agricultural land situated in loess region in Southern Moravia (Czech Republic) and subsequent laboratory analyses have been carried out in order to test the applicability of magnetic methods for the estimation of soil erosion. Chernozem, the original dominant soil unit in the wider area, is nowadays progressively transformed into different soil units along with intensive soil erosion. As a result, an extremely diversified soil cover structure has resulted from the erosion. The site was characterized by a flat upper part while the middle part, formed by a substantive side valley, is steeper (up to 15°). 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. We found a strong correlation between the volume magnetic susceptibility (field measurement) and mass specific magnetic susceptibility measured in the laboratory (R2 = 0.80). 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 magnetic susceptibility were obtained on the steep valley sides. Here the original topsoil was eroded and mixed by tillage with the soil substrate (loess). The soil profile that was unaffected by erosion was investigated in detail. The vertical distribution of magnetic susceptibility along this "virgin" profile was measured in laboratory on the samples from layers along the whole profile 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

Limitations of experiments performed in artificially made OECD standard soils for predicting cadmium, lead and zinc toxicity towards organisms living in natural soils.

PubMed

Sydow, Mateusz; Chrzanowski, Łukasz; Cedergreen, Nina; Owsianiak, Mikołaj

2017-08-01

Development of comparative toxicity potentials of cationic metals in soils for applications in hazard ranking and toxic impact assessment is currently jeopardized by the availability of experimental effect data. To compensate for this deficiency, data retrieved from experiments carried out in standardized artificial soils, like OECD soils, could potentially be tapped as a source of effect data. It is, however, unknown whether such data are applicable to natural soils where the variability in pore water concentrations of dissolved base cations is large, and where mass transfer limitations of metal uptake can occur. Here, free ion activity models (FIAM) and empirical regression models (ERM, with pH as a predictor) were derived from total metal EC50 values (concentration with effects in 50% of individuals) using speciation for experiments performed in artificial OECD soils measuring ecotoxicological endpoints for terrestrial earthworms, potworms, and springtails. The models were validated by predicting total metal based EC50 values using backward speciation employing an independent set of natural soils with missing information about ionic composition of pore water, as retrieved from a literature review. ERMs performed better than FIAMs. Pearson's r for log 10 -transformed total metal based EC50s values (ERM) ranged from 0.25 to 0.74, suggesting a general correlation between predicted and measured values. Yet, root-mean-square-error (RMSE) ranged from 0.16 to 0.87 and was either smaller or comparable with the variability of measured EC50 values, suggesting modest performance. This modest performance was mainly due to the omission of pore water concentrations of base cations during model development and their validation, as verified by comparisons with predictions of published terrestrial biotic ligand models. Thus, the usefulness of data from artificial OECD soils for global-scale assessment of terrestrial ecotoxic impacts of Cd, Pb and Zn in soils is limited due to

Potential phytoextraction and phytostabilization of perennial peanut on copper-contaminated vineyard soils and copper mining waste.

PubMed

Andreazza, Robson; Bortolon, Leandro; Pieniz, Simone; Giacometti, Marcelo; Roehrs, Dione D; Lambais, Mácio R; Camargo, Flávio A O

2011-12-01

This study sought to evaluate the potential of perennial peanut (Arachis pintoi) for copper phytoremediation in vineyard soils (Inceptisol and Mollisol) contaminated with copper and copper mining waste. Our results showed high phytomass production of perennial peanut in both vineyard soils. Macronutrient uptakes were not negatively affected by perennial peanut cultivated in all contaminated soils. Plants cultivated in Mollisol showed high copper concentrations in the roots and shoots of 475 and 52 mg kg(-1), respectively. Perennial peanut plants showed low translocation factor values for Cu, although these plants showed high bioaccumulation factor (BCF) for both vineyard soils, Inceptisol and Mollisol, with BCF values of 3.83 and 3.24, respectively, being characterized as a copper hyperaccumulator plant in these soils. Copper phytoextraction from Inceptisol soil was the highest for both roots and entire plant biomass, with more than 800 mg kg(-1) of copper in whole plant. The highest potential copper phytoextraction by perennial peanut was in Inceptisol soil with copper removal of 2,500 g ha(-1). Also, perennial peanut showed high potential for copper phytoremoval in copper mining waste and Mollisol with 1,700 and 1,500 g of copper per hectare, respectively. In addition, perennial peanuts characterized high potential for phytoextraction and phytostabilization of copper in vineyard soils and copper mining waste.

Influence of Herbicide Triasulfuron on Soil Microbial Community in an Unamended Soil and a Soil Amended with Organic Residues

PubMed Central

Pose-Juan, Eva; Igual, José M.; Sánchez-Martín, María J.; Rodríguez-Cruz, M. S.

2017-01-01

The effect of organic amendments and pesticides on a soil microbial community has garnered considerable interest due to the involvement of microorganisms in numerous soil conservation and maintenance reactions. The aim of this work was to assess the influence on a soil microbial community of the simultaneous application of the herbicide triasulfuron at three doses (2, 10, and 50 mg kg-1), with an organic amendment [sewage sludge (SS) or green compost (GC)]. Dissipation kinetics, soil microbial biomass, dehydrogenase activity (DHA) and respiration, and the profile of phospholipid fatty acids (PLFAs) extracted from the soil, were determined in unamended (S) soil and amended (S+SS and S+GC) ones. Triasulfuron dissipation followed the single first-order kinetics model. Half-life (DT50) values were higher in the amended soils than in the unamended one for the 10 and 50 mg kg-1 doses. The dissipation rates were lower in the S+GC soil for the three herbicide doses applied. In general, soil biomass, DHA and respiration values increased in SS- and GC-amended soils compared to the unamended one. DHA values decreased (S and S+SS) or increased (S+GC) with the incubation time of soil with herbicide at the different doses applied. Respiration values increased with the herbicide doses applied and decreased with the incubation time, although maximum values were obtained for soils treated with the highest dose after 70 days of incubation. PLFA analysis indicated different effects of triasulfuron on the soil microbial community structure depending on the organic amendments. While the increasing triasulfuron doses resulted in deeper alterations in the S soil, the time after triasulfuron application was the most important variation in the S+SS and S+GC soils. The overall results indicate that the soil amendment has an effect on herbicide dissipation rate and the soil microbial community. Initially, a high dose of triasulfuron had detrimental effects on the soil microbial community

Dynamic Site Characterization and Correlation of Shear Wave Velocity with Standard Penetration Test ` N' Values for the City of Agartala, Tripura State, India

NASA Astrophysics Data System (ADS)

Sil, Arjun; Sitharam, T. G.

2014-08-01

Seismic site characterization is the basic requirement for seismic microzonation and site response studies of an area. Site characterization helps to gauge the average dynamic properties of soil deposits and thus helps to evaluate the surface level response. This paper presents a seismic site characterization of Agartala city, the capital of Tripura state, in the northeast of India. Seismically, Agartala city is situated in the Bengal Basin zone which is classified as a highly active seismic zone, assigned by Indian seismic code BIS-1893, Indian Standard Criteria for Earthquake Resistant Design of Structures, Part-1 General Provisions and Buildings. According to the Bureau of Indian Standards, New Delhi (2002), it is the highest seismic level (zone-V) in the country. The city is very close to the Sylhet fault (Bangladesh) where two major earthquakes ( M w > 7) have occurred in the past and affected severely this city and the whole of northeast India. In order to perform site response evaluation, a series of geophysical tests at 27 locations were conducted using the multichannel analysis of surface waves (MASW) technique, which is an advanced method for obtaining shear wave velocity ( V s) profiles from in situ measurements. Similarly, standard penetration test (SPT-N) bore log data sets have been obtained from the Urban Development Department, Govt. of Tripura. In the collected data sets, out of 50 bore logs, 27 were selected which are close to the MASW test locations and used for further study. Both the data sets ( V s profiles with depth and SPT-N bore log profiles) have been used to calculate the average shear wave velocity ( V s30) and average SPT-N values for the upper 30 m depth of the subsurface soil profiles. These were used for site classification of the study area recommended by the National Earthquake Hazard Reduction Program (NEHRP) manual. The average V s30 and SPT-N classified the study area as seismic site class D and E categories, indicating that

The value of metals bioavailability and speciation information for ecological risk assessment in arid soils.

PubMed

Suedel, Burton C; Nicholson, Andrew; Day, Christopher H; Spicer, James

2006-10-01

When evaluating the risk chemicals may pose to mammals and birds in ecological risk assessments (ERAs), it is common practice to conservatively assume that all (100%) of a chemical in an environmental medium is bioavailable to receptors. This assumption often leads to overestimating ecological risk and may ultimately result in costly and unnecessary risk management actions. While effects of bioavailability and speciation of metals such as arsenic (As) and lead (Pb) have been considered in human health risk assessment, these effects are rarely taken into consideration when assessing risks to mammals and birds. An ERA was conducted at the former Col-Tex refinery site in Colorado City, Texas, USA, to characterize risks to select wildlife species from exposure to chromium (Cr) and Pb found in soils. The focus on these metals was based on results of a screening-level ERA that found that Cr and Pb were posing ecological risks at the site. Soils were analyzed for total Cr and Pb, trivalent Cr (CrIII), hexavalent Cr (CrVI), organic Pb, and the bioavailability and speciation of Pb. Results for Pb and Cr indicated that >94% of the Cr was present as the less toxic and immobile Cr(III) and that >99% of the Pb in soils was present as inorganic Pb. Lead bioaccessibility measured by in vitro testing ranged from 8% to 77.8%, depending on location of individual soil samples. Results demonstrated that Pb and Cr bioavailability and speciation information can raise soil cleanup concentrations while being protective of ecological receptors. The costs of performing the ERA were de minimus compared to the reduction in remediation costs at the site. The refined hazard estimates allowed informed decision making in the management and segregation of soils, allowing for effective risk management at the site.

Screening and Characterization of Potentially Suppressive Soils against Gaeumannomyces graminis under Extensive Wheat Cropping by Chilean Indigenous Communities.

PubMed

Durán, Paola; Jorquera, Milko; Viscardi, Sharon; Carrion, Victor J; Mora, María de la Luz; Pozo, María J

2017-01-01

Wheat production around the world is severely compromised by the occurrence of "take-all" disease, which is caused by the soil-borne pathogen Gaeumannomyces graminis var. tritici (Ggt). In this context, suppressive soils are those environments in which plants comparatively suffer less soil-borne pathogen diseases than expected, owing to native soil microorganism activities. In southern Chile, where 85% of the national cereal production takes place, several studies have suggested the existence of suppressive soils under extensive wheat cropping. Thus, this study aimed to screen Ggt-suppressive soil occurrence in 16 locations managed by indigenous "Mapuche" communities, using extensive wheat cropping for more than 10 years. Ggt growth inhibition in vitro screenings allowed the identification of nine putative suppressive soils. Six of these soils, including Andisols and Ultisols, were confirmed to be suppressive, since they reduced take-all disease in wheat plants growing under greenhouse conditions. Suppressiveness was lost upon soil sterilization, and recovered by adding 1% of the natural soil, hence confirming that suppressiveness was closely associated to the soil microbiome community composition. Our results demonstrate that long-term extensive wheat cropping, established by small Mapuche communities, can generate suppressive soils that can be used as effective microorganism sources for take-all disease biocontrol. Accordingly, suppressive soil identification and characterization are key steps for the development of environmentally-friendly and efficient biotechnological applications for soil-borne disease control.

Impact assessment of intermediate soil cover on landfill stabilization by characterizing landfilled municipal solid waste.

PubMed

Qi, Guangxia; Yue, Dongbei; Liu, Jianguo; Li, Rui; Shi, Xiaochong; He, Liang; Guo, Jingting; Miao, Haomei; Nie, Yongfeng

2013-10-15

Waste samples at different depths of a covered municipal solid waste (MSW) landfill in Beijing, China, were excavated and characterized to investigate the impact of intermediate soil cover on waste stabilization. A comparatively high amount of unstable organic matter with 83.3 g kg(-1) dry weight (dw) total organic carbon was detected in the 6-year-old MSW, where toxic inorganic elements containing As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn of 10.1, 0.98, 85.49, 259.7, 530.4, 30.5, 84.0, and 981.7 mg kg(-1) dw, respectively, largely accumulated because of the barrier effect of intermediate soil cover. This accumulation resulted in decreased microbial activities. The intermediate soil cover also caused significant reduction in moisture in MSW under the soil layer, which was as low as 25.9%, and led to inefficient biodegradation of 8- and 10-year-old MSW. Therefore, intermediate soil cover with low permeability seems to act as a barrier that divides a landfill into two landfill cells with different degradation processes by restraining water flow and hazardous matter. Copyright © 2013 Elsevier Ltd. All rights reserved.

Local versus field scale soil heterogeneity characterization - a challenge for representative sampling in pollution studies

NASA Astrophysics Data System (ADS)

Kardanpour, Z.; Jacobsen, O. S.; Esbensen, K. H.

2015-06-01

This study is a contribution to development of a heterogeneity characterisation facility for "next generation" sampling aimed at more realistic and controllable pesticide variability in laboratory pots in experimental environmental contaminant assessment. The role of soil heterogeneity on quantification of a set of exemplar parameters, organic matter, loss on ignition (LOI), biomass, soil microbiology, MCPA sorption and mineralization is described, including a brief background on how heterogeneity affects sampling/monitoring procedures in environmental pollutant studies. The Theory of Sampling (TOS) and variographic analysis has been applied to develop a fit-for-purpose heterogeneity characterization approach. All parameters were assessed in large-scale profile (1-100 m) vs. small-scale (0.1-1 m) replication sampling pattern. Variographic profiles of experimental analytical results concludes that it is essential to sample at locations with less than a 2.5 m distance interval to benefit from spatial auto-correlation and thereby avoid unnecessary, inflated compositional variation in experimental pots; this range is an inherent characteristic of the soil heterogeneity and will differ among soils types. This study has a significant carrying-over potential for related research areas e.g. soil science, contamination studies, and environmental monitoring and environmental chemistry.

Community level physiological profiles (CLPP), characterization and microbial activity of soil amended with dairy sewage sludge.

PubMed

Frąc, Magdalena; Oszust, Karolina; Lipiec, Jerzy

2012-01-01

The aim of the present work was to assess the influence of organic amendment applications compared to mineral fertilization on soil microbial activity and functional diversity. The field experiment was set up on a soil classified as an Eutric Cambisol developed from loess (South-East Poland). Two doses of both dairy sewage sludge (20 Mg·ha(-1) and 26 Mg·ha(-1)) and of mineral fertilizers containing the same amount of nutrients were applied. The same soil without any amendment was used as a control. The soil under undisturbed native vegetation was also included in the study as a representative background sample. The functional diversity (catabolic potential) was assessed using such indices as Average Well Color Development (AWCD), Richness (R) and Shannon-Weaver index (H). These indices were calculated, following the community level physiological profiling (CLPP) using Biolog Eco Plates. Soil dehydrogenase and respiratory activity were also evaluated. The indices were sensitive enough to reveal changes in community level physiological profiles due to treatment effects. It was shown that dairy sewage amended soil was characterized by greater AWCD, R, H and dehydrogenase and respiratory activity as compared to control or mineral fertilized soil. Analysis of variance (ANOVA) and principal component analysis (PCA) were used to depict the differences of the soil bacterial functional diversity between the treatments.

Community Level Physiological Profiles (CLPP), Characterization and Microbial Activity of Soil Amended with Dairy Sewage Sludge

PubMed Central

Frąc, Magdalena; Oszust, Karolina; Lipiec, Jerzy

2012-01-01

The aim of the present work was to assess the influence of organic amendment applications compared to mineral fertilization on soil microbial activity and functional diversity. The field experiment was set up on a soil classified as an Eutric Cambisol developed from loess (South-East Poland). Two doses of both dairy sewage sludge (20 Mg·ha−1 and 26 Mg·ha−1) and of mineral fertilizers containing the same amount of nutrients were applied. The same soil without any amendment was used as a control. The soil under undisturbed native vegetation was also included in the study as a representative background sample. The functional diversity (catabolic potential) was assessed using such indices as Average Well Color Development (AWCD), Richness (R) and Shannon–Weaver index (H). These indices were calculated, following the community level physiological profiling (CLPP) using Biolog Eco Plates. Soil dehydrogenase and respiratory activity were also evaluated. The indices were sensitive enough to reveal changes in community level physiological profiles due to treatment effects. It was shown that dairy sewage amended soil was characterized by greater AWCD, R, H and dehydrogenase and respiratory activity as compared to control or mineral fertilized soil. Analysis of variance (ANOVA) and principal component analysis (PCA) were used to depict the differences of the soil bacterial functional diversity between the treatments. PMID:22737006

Soil organic matter persistence as a stochastic process: age and transit time distributions of carbon in soils

NASA Astrophysics Data System (ADS)

Sierra, Carlos

2017-04-01

The question of why some organic matter is more persistent than other that decomposes quickly in soils has sparkled a large amount of research in recent years. Persistence is commonly characterized as the turnover or mean residence time of specific compounds or soil organic matter (SOM) pools. However, turnover and residence times are ambiguous measures of persistence, which is better characterized by the probability distribution of ages in the system and in particular pools. We calculated age distributions for a wide range of SOM models, which showed long-tail distributions far from the mean value. Age and transit time distributions from a variety of models also showed: 1) transit times are lower than ages of SOM, 2) turnover times differ significantly from mean ages in slow cycling pools, 3) change in the inputs, without changes in the allocation of photosynthetic products, has no effect on transit times, but does affect system and pool ages. We propose an index to assess persistence of C in soils that can be derived from observations alone or from models. We also ask whether random chance is an important contributor to the persistence of SOM.

Soil variability in engineering applications

NASA Astrophysics Data System (ADS)

Vessia, Giovanna

2014-05-01

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

Cadmium availability in rice paddy fields from a mining area: The effects of soil properties highlighting iron fractions and pH value.

PubMed

Yu, Huan-Yun; Liu, Chuanping; Zhu, Jishu; Li, Fangbai; Deng, Dong-Mei; Wang, Qi; Liu, Chengshuai

2016-02-01

Cadmium (Cd) availability can be significantly affected by soil properties. The effect of pH value on Cd availability has been confirmed. Paddy soils in South China generally contain high contents of iron (Fe). Thus, it is hypothesized that Fe fractions, in addition to pH value, may play an important role in the Cd bioavailability in paddy soil and this requires further investigation. In this study, 73 paired soil and rice plant samples were collected from paddy fields those were contaminated by acid mine drainage containing Cd. The contents of Fe in the amorphous and DCB-extractable Fe oxides were significantly and negatively correlated with the Cd content in rice grain or straw (excluding DCB-extractable Fe vs Cd in straw). In addition, the concentration of HCl-extractable Fe(II) derived from Fe(III) reduction was positively correlated with the Cd content in rice grain or straw. These results suggest that soil Fe redox could affect the availability of Cd in rice plant. Contribution assessment of soil properties to Cd accumulation in rice grain based on random forest (RF) and stochastic gradient boosting (SGB) showed that pH value should be the most important factor and the content of Fe in the amorphous Fe oxides should be the second most important factor in affecting Cd content in rice grain. Overall, compared with the studies from temperate regions, such as Europe and northern China, Fe oxide exhibited its unique role in the bioavailability of Cd in the reddish paddy soil from our study area. The exploration of practical remediation strategies for Cd from the perspective of Fe oxide may be promising. Copyright © 2015 Elsevier Ltd. All rights reserved.

Soil porosity correlation and its influence in percolation dynamics

NASA Astrophysics Data System (ADS)

Rodriguez, Alfredo; Capa-Morocho, Mirian; Ruis-Ramos, Margarita; Tarquis, Ana M.

2016-04-01

The prediction of percolation in natural soils is relevant for modeling root growth and optimizing infiltration of water and nutrients. Also, it would improve our understanding on how pollutants as pesticides, and virus and bacteria (Darnault et al., 2003) reach significant depths without being filtered out by the soil matrix (Beven and Germann, 2013). Random walk algorithms have been used successfully to date to characterize the dynamical characteristics of disordered media. This approach has been used here to describe how soil at different bulk densities and with different threshold values applied to the 3D gray images influences the structure of the pore network and their implications on particle flow and distribution (Ruiz-Ramos et al., 2009). In order to do so first we applied several threshold values to each image analyzed and characterized them through Hurst exponents, then we computed random walks algorithms to calculate distances reached by the particles and speed of those particles. At the same time, 3D structures with a Hurst exponent of ca 0.5 and with different porosities were constructed and the same random walks simulations were replicated over these generated structures. We have found a relationship between Hurst exponents and the speed distribution of the particles reaching percolation of the total soil depth. REFERENCES Darnault, C.J. G., P. Garnier, Y.J. Kim, K.L. Oveson, T.S. Steenhuis, J.Y. Parlange, M. Jenkins, W.C. Ghiorse, and P. Baveye (2003), Preferential transport of Cryptosporidium parvum oocysts in variably saturated subsurface environments, Water Environ. Res., 75, 113-120. Beven, Keith and Germann, Peter. 2013. Macropores and water flow in soils revisited. Water Resources Research, 49(6), 3071-3092. DOI: 10.1002/wrcr.20156. Ruiz-Ramos, M., D. del Valle, D. Grinev, and A.M. Tarquis. 2009. Soil hydraulic behaviour at different bulk densities. Geophysical Research Abstracts, 11, EGU2009-6234.

Isolation and characterization of oxalotrophic bacteria from tropical soils.

PubMed

Bravo, Daniel; Braissant, Olivier; Cailleau, Guillaume; Verrecchia, Eric; Junier, Pilar

2015-01-01

The oxalate-carbonate pathway (OCP) is a biogeochemical set of reactions that involves the conversion of atmospheric CO2 fixed by plants into biomass and, after the biological recycling of calcium oxalate by fungi and bacteria, into calcium carbonate in terrestrial environments. Oxalotrophic bacteria are a key element of this process because of their ability to oxidize calcium oxalate. However, the diversity and alternative carbon sources of oxalotrophs participating to this pathway are unknown. Therefore, the aim of this study was to characterize oxalotrophic bacteria in tropical OCP systems from Bolivia, India, and Cameroon. Ninety-five oxalotrophic strains were isolated and identified by sequencing of the 16S rRNA gene. Four genera corresponded to newly reported oxalotrophs (Afipia, Polaromonas, Humihabitans, and Psychrobacillus). Ten strains were selected to perform a more detailed characterization. Kinetic curves and microcalorimetry analyses showed that Variovorax soli C18 has the highest oxalate consumption rate with 0.240 µM h(-1). Moreover, Streptomyces achromogenes A9 displays the highest metabolic plasticity. This study highlights the phylogenetic and physiological diversity of oxalotrophic bacteria in tropical soils under the influence of the oxalate-carbonate pathway.

Screening and Characterization of Potentially Suppressive Soils against Gaeumannomyces graminis under Extensive Wheat Cropping by Chilean Indigenous Communities

PubMed Central

Durán, Paola; Jorquera, Milko; Viscardi, Sharon; Carrion, Victor J.; Mora, María de la Luz; Pozo, María J.

2017-01-01

Wheat production around the world is severely compromised by the occurrence of “take-all” disease, which is caused by the soil-borne pathogen Gaeumannomyces graminis var. tritici (Ggt). In this context, suppressive soils are those environments in which plants comparatively suffer less soil-borne pathogen diseases than expected, owing to native soil microorganism activities. In southern Chile, where 85% of the national cereal production takes place, several studies have suggested the existence of suppressive soils under extensive wheat cropping. Thus, this study aimed to screen Ggt-suppressive soil occurrence in 16 locations managed by indigenous “Mapuche” communities, using extensive wheat cropping for more than 10 years. Ggt growth inhibition in vitro screenings allowed the identification of nine putative suppressive soils. Six of these soils, including Andisols and Ultisols, were confirmed to be suppressive, since they reduced take-all disease in wheat plants growing under greenhouse conditions. Suppressiveness was lost upon soil sterilization, and recovered by adding 1% of the natural soil, hence confirming that suppressiveness was closely associated to the soil microbiome community composition. Our results demonstrate that long-term extensive wheat cropping, established by small Mapuche communities, can generate suppressive soils that can be used as effective microorganism sources for take-all disease biocontrol. Accordingly, suppressive soil identification and characterization are key steps for the development of environmentally-friendly and efficient biotechnological applications for soil-borne disease control. PMID:28861064

Spatial interpolation of soil organic carbon using apparent electrical conductivity as secondary information

NASA Astrophysics Data System (ADS)

Martinez, G.; Vanderlinden, K.; Ordóñez, R.; Muriel, J. L.

2009-04-01

Soil organic carbon (SOC) spatial characterization is necessary to evaluate under what circumstances soil acts as a source or sink of carbon dioxide. However, at the field or catchment scale it is hard to accurately characterize its spatial distribution since large numbers of soil samples are necessary. As an alternative, near-surface geophysical sensor-based information can improve the spatial estimation of soil properties at these scales. Electromagnetic induction (EMI) sensors provide non-invasive and non-destructive measurements of the soil apparent electrical conductivity (ECa), which depends under non-saline conditions on clay content, water content or SOC, among other properties that determine the electromagnetic behavior of the soil. This study deals with the possible use of ECa-derived maps to improve SOC spatial estimation by Simple Kriging with varying local means (SKlm). Field work was carried out in a vertisol in SW Spain. The field is part of a long-term tillage experiment set up in 1982 with three replicates of conventional tillage (CT) and Direct Drilling (DD) plots with unitary dimensions of 15x65m. Shallow and deep (up to 0.8m depth) apparent electrical conductivity (ECas and ECad, respectively) was measured using the EM38-DD EMI sensor. Soil samples were taken from the upper horizont and analyzed for their SOC content. Correlation coefficients of ECas and ECad with SOC were low (0.331 and 0.175) due to the small range of SOC values and possibly also to the different support of the ECa and SOC data. Especially the ECas values were higher in the DD plots. The normalized ECa difference (ΔECa), calculated as the difference between the normalized ECas and ECad values, distinguished clearly the CT and DD plots, with the DD plots showing positive ΔECa values and CT plots ΔECa negative values. The field was stratified using fuzzy k-means (FKM) classification of ΔECa (FKM1), and ECas and ECad (FKM2). The FKM1 map mainly showed the difference between

Fractionation and characterization of soil organic carbon during transition to organic farming

NASA Astrophysics Data System (ADS)

Abdelrahman, H.; Olk, D.; Cocozza, C.; Miano, T.

2012-04-01

The transition from conventional to organic farming is the most difficult period faced by organic growers as it could be characterized by unstable conditions, such as nutrient availability, production reductions, mineralization extents. As soil organic matter (SOM), specifically soil organic carbon (SOC), is known to play important roles in maintenance and improvement of many soil properties, it is important to define its changes during the transition period. Total SOC might not be the suitable tool to track the changes in organically based soil fertility within a 3- to 5-yr transition period. Labile fractions that are important for nutrient cycling and supply are likely to be controlled by management to a much greater extent than is total SOM. Two field experiments, in south of Italy, were established in 2009 to study the changes in SOC during transition to organic farming. Experiments included a cereal/leguminous rotation with triplicates treatments of permitted amendments (compost and fertilizers). Soils were sampled at the beginning of the project, and after each crop harvest in 2010 and 2011. A sequential fractionation procedure was used to separate different SOC-fractions: light fraction (LF), two size classes of particulate organic matter (POM), mobile humic acid (MHA) and Ca++ bound humic acid (CaHA). Isolated fractions were quantified and analyzed for their content of C, N, carbohydrates and amino compounds fingerprints. The obtained results showed that compost application contributed to significantly higher quantities of LF, POM and MHA than did fertilizers application. Carbohydrates content decreased in LF while increased noticeably in POM and slightly in MHA fractions, which indicates that decomposing materials are converted, within the time span of humification, from young fractions into more mature fractions. Amino compounds were found to provide up to 40% of total soil N with a major contribution of the humified fractions, MHA and CaHA. The utilized

Microscopic and spectroscopic characterization of humic substances from a compost amended copper contaminated soil: main features and their potential effects on Cu immobilization.

PubMed

Medina, Jorge; Monreal, Carlos; Chabot, Denise; Meier, Sebastián; González, María Eugenia; Morales, Esteban; Parillo, Rita; Borie, Fernando; Cornejo, Pablo

2017-06-01

We characterized humic substances (HS) extracted from a Cu-contaminated soil without compost addition (C) or amended with a wheat straw-based compost (WSC) (H1), co-composted with Fe 2 O 3 (H2), or co-composted with an allophane-rich soil (H3). Extracted HS were characterized under electron microscopy (SEM/TEM), energy-dispersive X-ray (X-EDS), and Fourier transform infrared (FTIR) spectroscopy. In addition, HS extracted from WSC (H4) were characterized at pH 4.0 and 8.0 with descriptive purposes. At pH 4.0, globular structures of H4 were observed, some of them aggregating within a large network. Contrariwise, at pH 8.0, long tubular and disaggregated structures prevailed. TEM microscopy suggests organo-mineral interactions at scales of 1 to 200 nm with iron oxide nanoparticles. HS extracted from soil-compost incubations showed interactions at nanoscale with minerals and crystal compounds into the organic matrix of HS. Bands associated to acidic functional groups of HS may suggest potential sorption interactions with transition metals. We conclude that metal ions and pH have an important role controlling the morphology and configuration of HS from WSC. Characterization of H4 extracted from WSC showed that physicochemical protection of HS could be present in composting systems treated with inorganic materials. Finally, the humified fractions obtained from compost-amended soils may have an important effect on metal-retention, supporting their potential use in metal-contaminated soils.

Delineation of colluvial soils in different soil regions

NASA Astrophysics Data System (ADS)

Zádorová, Tereza; Penížek, Vít; Vašát, Radim

2015-04-01

Colluvial soils are considered to be the direct result of accelerated soil erosion in agricultural landscape, resulting in accumulation of humus-rich soil material in terrain depressions and toe slopes. They represent an important soil cover element in landscapes influenced by soil erosion and form an important soil organic carbon (SOC) pool. Delineation of colluvial soils can identify areas with high sediment input and potential deep organic carbon storage and thus improve our knowledge on soil mass and SOC stock redistribution in dissected landscapes. Different prediction methods (ordinary kriging, multiple linear regression, supervised fuzzy classification, artificial neural network, support vector machines) for colluvial soils delineation have been tested in three different soil regions (Cambisol, Luvisol and Chernozem) at two scales (plot and watershed) in the Czech Republic. The approach is based on exploitation of relationship between soil and terrain units and assumes that colluvial soil can be defined by particular range of terrain attributes values. Terrain attributes derived from precise DEMs were used as predictors in applied models. The soil-terrain relationship was assessed using a large dataset of field investigations (300 cores at each plot and 100 cores at each watershed). Models were trained at plot scale (15-33 ha) and the best performing model was then calibrated and validated at watershed scale (25-55 km2). The study proved high potential of terrain variables as predictors in colluvial soil delineation. Support vector machines method was the best performing method for colluvial soil occurrence prediction at all the three sites. However, significant differences in performance have been identified among the studied plots. The best results were obtained in Luvisol region where both determination coefficient and prediction accuracy reached the highest values. The model performance was satisfactory also in Chernozem region. The model showed its

Agricultural areas in potentially contaminated sites: characterization, risk, management.

PubMed

Vanni, Fabiana; Scaini, Federica; Beccaloni, Eleonora

2016-01-01

In Italy, the current legislation for contaminants in soils provides two land uses: residential/public or private gardens and commercial/industrial; there are not specific reference values for agricultural soils, even if a special decree has been developed and is currently going through the legislative approval process. The topic of agricultural areas is relevant, also in consideration of their presence near potentially contaminated sites. Aim and results. In this paper, contamination sources and transport modes of contaminants from sources to the target in agricultural areas are examined and a suitable "conceptual model" to define appropriate characterization methods and risk assessment procedures is proposed. These procedures have already been used by the National Institute of Health in various Italian areas characterized by different agricultural settings. Finally, specific remediation techniques are suggested to preserve soil resources and, if possible, its particular land use.

δ13C values of soil organic matter in semiarid grassland with mesquite (Prosopis) encroachment in southeastern Arizona

USGS Publications Warehouse

Biggs, Thomas H.; Quade, Jay; Webb, Robert H.

2002-01-01

Over the past century, C3 woody plants and trees have increased in abundance in many semiarid ecosystems, displacing native C4 grasses. Livestock grazing, climatic fluctuations, and fire suppression are several reasons proposed for this shift. Soil carbon isotopic signatures are an ideal technique to evaluate carbon turnover rates in such ecosystems. On the gunnery ranges of Fort Huachuca in southeastern Arizona, study sites were established on homogeneous granitic alluvium to investigate the effects of fire frequency on δ13C values in surface soil organic matter (SOM). These ranges have had no livestock grazing for 50 years and a well-documented history of fires. Prosopis velutina Woot. (mesquite) trees have altered SOM δ13C pools by the concentration of plant nutrients and the addition of isotopically light litter. These soil carbon changes do not extend beyond canopy margins. Elevated total organic carbon (TOC), plant nutrient (N and P) concentrations, and depleted SOM δ13C values are associated with C3Prosopis on an unburned plot, which enables recognition of former Prosopis-occupied sites on plots with recent fire histories. Elevated nutrient concentrations associated with former Prosopis are retained in SOM for many decades. Surface SOM δ13C values indicate the estimated minimum turnover time of C4-derived carbon beneath large mature Prosopis is about 100–300 years. In contrast, complete turnover of original C3 carbon to C4 carbon under grasslands is estimated to take a minimum of 150–500 years. Our study confirms that C4 grass cover has declined over the past 100 years, although isolated C3 trees or shrubs were not uncommon on the historic C4-dominated grasslands. We find evidence in surface soil layers for a modern C3 plant expansion reflected in the substantial shift of SOM δ13C values from C4 grasses to C3 shrublands.

Characterization of Soil Suppressiveness to Root-Knot Nematodes in Organic Horticulture in Plastic Greenhouse

PubMed Central

Giné, Ariadna; Carrasquilla, Marc; Martínez-Alonso, Maira; Gaju, Núria; Sorribas, Francisco J.

2016-01-01

The fluctuation of Meloidogyne population density and the percentage of fungal egg parasitism were determined from July 2011 to July 2013 in two commercial organic vegetable production sites (M10.23 and M10.55) in plastic greenhouses, located in northeastern Spain, in order to know the level of soil suppressiveness. Fungal parasites were identified by molecular methods. In parallel, pot tests characterized the level of soil suppressiveness and the fungal species growing from the eggs. In addition, the egg parasitic ability of 10 fungal isolates per site was also assessed. The genetic profiles of fungal and bacterial populations from M10.23 and M10.55 soils were obtained by Denaturing Gradient Gel Electrophoresis (DGGE), and compared with a non-suppressive soil (M10.33). In M10.23, Meloidogyne population in soil decreased progressively throughout the rotation zucchini, tomato, and radish or spinach. The percentage of egg parasitism was 54.7% in zucchini crop, the only one in which eggs were detected. Pochonia chlamydosporia was the only fungal species isolated. In M10.55, nematode densities peaked at the end of the spring-summer crops (tomato, zucchini, and cucumber), but disease severity was lower than expected (0.2–6.3). The percentage of fungal egg parasitism ranged from 3 to 84.5% in these crops. The results in pot tests confirmed the suppressiveness of the M10.23 and M10.55 soils against Meloidogyne. The number of eggs per plant and the reproduction factor of the population were reduced (P < 0.05) in both non-sterilized soils compared to the sterilized ones after one nematode generation. P. chlamydosporia was the only fungus isolated from Meloidogyne eggs. In in vitro tests, P. chlamydosporia isolates were able to parasitize Meloidogyne eggs from 50 to 97% irrespective of the site. DGGE fingerprints revealed a high diversity in the microbial populations analyzed. Furthermore, both bacterial and fungal genetic patterns differentiated suppressive from non

Characterization of Soil Suppressiveness to Root-Knot Nematodes in Organic Horticulture in Plastic Greenhouse.

PubMed

Giné, Ariadna; Carrasquilla, Marc; Martínez-Alonso, Maira; Gaju, Núria; Sorribas, Francisco J

2016-01-01

The fluctuation of Meloidogyne population density and the percentage of fungal egg parasitism were determined from July 2011 to July 2013 in two commercial organic vegetable production sites (M10.23 and M10.55) in plastic greenhouses, located in northeastern Spain, in order to know the level of soil suppressiveness. Fungal parasites were identified by molecular methods. In parallel, pot tests characterized the level of soil suppressiveness and the fungal species growing from the eggs. In addition, the egg parasitic ability of 10 fungal isolates per site was also assessed. The genetic profiles of fungal and bacterial populations from M10.23 and M10.55 soils were obtained by Denaturing Gradient Gel Electrophoresis (DGGE), and compared with a non-suppressive soil (M10.33). In M10.23, Meloidogyne population in soil decreased progressively throughout the rotation zucchini, tomato, and radish or spinach. The percentage of egg parasitism was 54.7% in zucchini crop, the only one in which eggs were detected. Pochonia chlamydosporia was the only fungal species isolated. In M10.55, nematode densities peaked at the end of the spring-summer crops (tomato, zucchini, and cucumber), but disease severity was lower than expected (0.2-6.3). The percentage of fungal egg parasitism ranged from 3 to 84.5% in these crops. The results in pot tests confirmed the suppressiveness of the M10.23 and M10.55 soils against Meloidogyne. The number of eggs per plant and the reproduction factor of the population were reduced (P < 0.05) in both non-sterilized soils compared to the sterilized ones after one nematode generation. P. chlamydosporia was the only fungus isolated from Meloidogyne eggs. In in vitro tests, P. chlamydosporia isolates were able to parasitize Meloidogyne eggs from 50 to 97% irrespective of the site. DGGE fingerprints revealed a high diversity in the microbial populations analyzed. Furthermore, both bacterial and fungal genetic patterns differentiated suppressive from non

Effect of soil texture on the microwave emission from soils

NASA Technical Reports Server (NTRS)

Schmugge, T. J.

1980-01-01

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

Relevant magnetic and soil parameters as potential indicators of soil conservation status of Mediterranean agroecosystems

NASA Astrophysics Data System (ADS)

Quijano, Laura; Chaparro, Marcos A. E.; Marié, Débora C.; Gaspar, Leticia; Navas, Ana

2014-09-01

The main sources of magnetic minerals in soils unaffected by anthropogenic pollution are iron oxides and hydroxides derived from parent materials through soil formation processes. Soil magnetic minerals can be used as indicators of environmental factors including soil forming processes, degree of pedogenesis, weathering processes and biological activities. In this study measurements of magnetic susceptibility are used to detect the presence and the concentration of soil magnetic minerals in topsoil and bulk samples in a small cultivated field, which forms a hydrological unit that can be considered to be representative of the rainfed agroecosystems of Mediterranean mountain environments. Additional magnetic studies such as isothermal remanent magnetization (IRM), anhysteretic remanent magnetization (ARM) and thermomagnetic measurements are used to identify and characterize the magnetic mineralogy of soil minerals. The objectives were to analyse the spatial variability of the magnetic parameters to assess whether topographic factors, soil redistribution processes, and soil properties such as soil texture, organic matter and carbonate contents analysed in this study, are related to the spatial distribution pattern of magnetic properties. The medians of mass specific magnetic susceptibility at low frequency (χlf) were 36.0 and 31.1 × 10-8 m3 kg-1 in bulk and topsoil samples respectively. High correlation coefficients were found between the χlf in topsoil and bulk core samples (r = 0.951, p < 0.01). In addition, volumetric magnetic susceptibility was measured in situ in the field (κis) and values varied from 13.3 to 64.0 × 10-5 SI. High correlation coefficients were found between χlf in topsoil measured in the laboratory and volumetric magnetic susceptibility field measurements (r = 0.894, p < 0.01). The results obtained from magnetic studies such as IRM, ARM and thermomagnetic measurements show the presence of magnetite, which is the predominant magnetic carrier

Characterization of magnetically enhanced buried soil layer in arid environment

NASA Astrophysics Data System (ADS)

Petrovsky, E.; Grison, H.; Kapicka, A.; Silva, P. F.; Font, E.

2011-12-01

Magnetic susceptibility (MS) of soils, reflecting the presence of magnetite/maghemite, can be used in several environmental applications. Magnetic topsoil mapping is often used to outline areas polluted by atmospherically deposited dust. However, in these studies, the magnetically enhanced layer is usually shallow, some 5-6 cm under the surface. In our contribution, we present the case when the magnetic susceptibility is enhanced in deeper soil layers. Investigated soils are mostly sandy soils, from several localities in Portugal, in a zone with arid climate. Sample profiles were collected always in forests or forest stands with pines, cork oaks or eucalyptus trees in two areas: around the city of Sines (on the coast south of Lisbon) and around the city of Abrantes (inland, north-east of Lisbon). Both areas are presumably affected by one major source of pollution - power plant. Surface magnetic susceptibility measurements were performed by Bartington MS2D loop; values vary from 10 to 300 x 10-5 SI units. Vertical distribution of magnetic susceptibility was measured already in situ using the SM400 (ZHInstruments) on profiles about 40cm in length. Mass-specific MS was determined using Bartington MS2B dual frequency meter and Agico MFK1. Nine vertical profiles were selected for detailed analyses including the ARM, IRM and hysteresis measurements. Distinctly enhanced magnetic layers were detected in deeper horizons. This enhancement can be ascribed to several mechanisms. Migration of magnetic particles seems to be probable, as observed in our model experiments with sand columns. In coastal areas, the enhanced layer could be due to tsunami deposits, as described in other areas. Finally, in particular at sites close to power plants, the construction works followed by surface remediation have to be also considered as one of the possible mechanisms.

Estimating Soil Organic Carbon Stocks and Spatial Patterns with Statistical and GIS-Based Methods

PubMed Central

Zhi, Junjun; Jing, Changwei; Lin, Shengpan; Zhang, Cao; Liu, Qiankun; DeGloria, Stephen D.; Wu, Jiaping

2014-01-01

Accurately quantifying soil organic carbon (SOC) is considered fundamental to studying soil quality, modeling the global carbon cycle, and assessing global climate change. This study evaluated the uncertainties caused by up-scaling of soil properties from the county scale to the provincial scale and from lower-level classification of Soil Species to Soil Group, using four methods: the mean, median, Soil Profile Statistics (SPS), and pedological professional knowledge based (PKB) methods. For the SPS method, SOC stock is calculated at the county scale by multiplying the mean SOC density value of each soil type in a county by its corresponding area. For the mean or median method, SOC density value of each soil type is calculated using provincial arithmetic mean or median. For the PKB method, SOC density value of each soil type is calculated at the county scale considering soil parent materials and spatial locations of all soil profiles. A newly constructed 1∶50,000 soil survey geographic database of Zhejiang Province, China, was used for evaluation. Results indicated that with soil classification levels up-scaling from Soil Species to Soil Group, the variation of estimated SOC stocks among different soil classification levels was obviously lower than that among different methods. The difference in the estimated SOC stocks among the four methods was lowest at the Soil Species level. The differences in SOC stocks among the mean, median, and PKB methods for different Soil Groups resulted from the differences in the procedure of aggregating soil profile properties to represent the attributes of one soil type. Compared with the other three estimation methods (i.e., the SPS, mean and median methods), the PKB method holds significant promise for characterizing spatial differences in SOC distribution because spatial locations of all soil profiles are considered during the aggregation procedure. PMID:24840890

Metagenomic Characterization and Biochemical Analysis of Cellulose-Degrading Bacterial Communities from Sheep Rumen, Termite Hindgut, Decaying Plant Materials, and Soil

DTIC Science & Technology

2016-01-04

Biochemical Analysis of Cellulose-DegradingBacterial Communities from Sheep Rumen, Termite Hindgut, Decaying Plant Materials,and Soil In an effort to...degrading bacteria from various samples, including termite gut, sheep rumen, soil, and decaying plant materials. Using selective media culture with...Metagenomic Characterization and Biochemical Analysis of Cellulose-DegradingBacterial Communities from Sheep Rumen, Termite Hindgut, Decaying Plant

Kd Values for Agricultural and Surface Soils for Use in Hanford Site Farm, Residential, and River Shoreline Scenarios

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

Serne, R. Jeffrey

This report provides best estimate Kd values and a minimum and maximum range of Kd values to be used for agricultural soils and Columbia River bank sediments that exist today or would exist in the future when portions of the Hanford Site are released for farming, residential, and recreational use after the U. S. Department of Energy (DOE) completes clean up of defense waste on the site. The Kd values should be used to determine the fate and transport rates of contaminants and their availability for plant and animal uptake in selected non-groundwater scenarios included in Hanford Site environmental impactmore » statements, risk assessments and specific facility performance assessments. This report describes scenarios such as a small farm where drilling of a well inadvertently goes through buried waste and brings waste to the surface, allowing the tailings to become available for direct human exposure or incorporation into garden crops and farm animals used for food by the farm family. The Kd values recommended in this report can also be used to calculate sediment-water partitioning factors used to predict plant and animal uptake from interaction with the contaminated soil.« less

NMR characterization and sorption behavior of agricultural and forest soil humic substances

NASA Astrophysics Data System (ADS)

Li, Chengliang; Berns, Anne E.; Séquaris, Jean-Marie; Klumpp, Erwin

2010-05-01

Humic substances are the predominant components of the organic matter in the terrestrial system, which are not only important for the physicochemical properties of soil but are also dominant factors for controlling the environmental behaviors and fates of some organic contaminants, such as hydrophobic compounds. Nonylphenol [4-(1-ethyl-1, 3 dimethylpentyl) phenol] (NP), a ubiquitous hydrophobic pollutant, has recently focused the attention owing to its endocrine disruptors property. Sorption behavior of NP on humic substances, which were isolated from agricultural and forest soils, was investigated by using the dialysis technique at room temperature. 14C-labeled NP was used to quantify the partitioning behavior. Humic substances were characterized by 13C Cross-Polarization/Magic-Angle-Spinning Nuclear Magnetic Resonance (CP/MAS NMR). The results showed that the partition parameters of NP on various humic acids were slightly different. Relationships between partition coefficients and the functional groups of humic substances identified by CP/MAS NMR were analyzed.

13C NMR spectroscopy characterization of particle-size fractionated soil organic carbon in subalpine forest and grassland ecosystems.

PubMed

Shiau, Yo-Jin; Chen, Jenn-Shing; Chung, Tay-Lung; Tian, Guanglong; Chiu, Chih-Yu

2017-12-01

Soil organic carbon (SOC) and carbon (C) functional groups in different particle-size fractions are important indicators of microbial activity and soil decomposition stages under wildfire disturbances. This research investigated a natural Tsuga forest and a nearby fire-induced grassland along a sampling transect in Central Taiwan with the aim to better understand the effect of forest wildfires on the change of SOC in different soil particle scales. Soil samples were separated into six particle sizes and SOC was characterized by solid-state 13 C nuclear magnetic resonance spectroscopy in each fraction. The SOC content was higher in forest than grassland soil in the particle-size fraction samples. The O-alkyl-C content (carbohydrate-derived structures) was higher in the grassland than the forest soils, but the alkyl-C content (recalcitrant substances) was higher in forest than grassland soils, for a higher humification degree (alkyl-C/O-alkyl-C ratio) in forest soils for all the soil particle-size fractions. High humification degree was found in forest soils. The similar aromaticity between forest and grassland soils might be attributed to the fire-induced aromatic-C content in the grassland that offsets the original difference between the forest and grassland. High alkyl-C content and humification degree and low C/N ratios in the fine particle-size fractions implied that undecomposed recalcitrant substances tended to accumulate in the fine fractions of soils.

Characterization of Trapped Lignin-Degrading Microbes in Tropical Forest Soil

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

DeAngelis, Kristen M.; Allgaier, Martin; Chavarria, Yaucin

2011-04-29

Lignin is often the most difficult portion of plant biomass to degrade, with fungi generally thought to dominate during late stage decomposition. Lignin in feedstock plant material represents a barrier to more efficient plant biomass conversion and can also hinder enzymatic access to cellulose, which is critical for biofuels production. Tropical rain forest soils in Puerto Rico are characterized by frequent anoxic conditions and fluctuating redox, suggesting the presence of lignin-degrading organisms and mechanisms that are different from known fungal decomposers and oxygen-dependent enzyme activities. We explored microbial lignin-degraders by burying bio-traps containing lignin-amended and unamended biosep beads in themore » soil for 1, 4, 13 and 30 weeks. At each time point, phenol oxidase and peroxidase enzyme activity was found to be elevated in the lignin-amended versus the unamended beads, while cellulolytic enzyme activities were significantly depressed in lignin-amended beads. Quantitative PCR of bacterial communities showed more bacterial colonization in the lignin-amended compared to the unamended beads after one and four weeks, suggesting that the lignin supported increased bacterial abundance. The microbial community was analyzed by small subunit 16S ribosomal RNA genes using microarray (PhyloChip) and by high-throughput amplicon pyrosequencing based on universal primers targeting bacterial, archaeal, and eukaryotic communities. Community trends were significantly affected by time and the presence of lignin on the beads. Lignin-amended beads have higher relative abundances of representatives from the phyla Actinobacteria, Firmicutes, Acidobacteria and Proteobacteria compared to unamended beads. This study suggests that in low and fluctuating redox soils, bacteria could play a role in anaerobic lignin decomposition.« less

Characterization of trapped lignin-degrading microbes in tropical forest soil

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

DeAngelis, K.M.; Allgaier, M.; Chavarria, Y.

2011-03-01

Lignin is often the most difficult portion of plant biomass to degrade, with fungi generally thought to dominate during late stage decomposition. Lignin in feedstock plant material represents a barrier to more efficient plant biomass conversion and can also hinder enzymatic access to cellulose, which is critical for biofuels production. Tropical rain forest soils in Puerto Rico are characterized by frequent anoxic conditions and fluctuating redox, suggesting the presence of lignin-degrading organisms and mechanisms that are different from known fungal decomposers and oxygen-dependent enzyme activities. We explored microbial lignin-degraders by burying bio-traps containing lignin-amended and unamended biosep beads in themore » soil for 1, 4, 13 and 30 weeks. At each time point, phenol oxidase and peroxidase enzyme activity was found to be elevated in the lignin-amended versus the unamended beads, while cellulolytic enzyme activities were significantly depressed in lignin-amended beads. Quantitative PCR of bacterial communities showed more bacterial colonization in the lignin-amended compared to the unamended beads after one and four weeks, suggesting that the lignin supported increased bacterial abundance. The microbial community was analyzed by small subunit 16S ribosomal RNA genes using microarray (PhyloChip) and by high-throughput amplicon pyrosequencing based on universal primers targeting bacterial, archaeal, and eukaryotic communities. Community trends were significantly affected by time and the presence of lignin on the beads. Lignin-amended beads have higher relative abundances of representatives from the phyla Actinobacteria, Firmicutes, Acidobacteria and Proteobacteria compared to unamended beads. This study suggests that in low and fluctuating redox soils, bacteria could play a role in anaerobic lignin decomposition.« less

Characterization of Trapped Lignin-Degrading Microbes in Tropical Forest Soil

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

DeAngelis, Kristen; Allgaier, Martin; Chavarria, Yaucin

2011-07-14

Lignin is often the most difficult portion of plant biomass to degrade, with fungi generally thought to dominate during late stage decomposition. Lignin in feedstock plant material represents a barrier to more efficient plant biomass conversion and can also hinder enzymatic access to cellulose, which is critical for biofuels production. Tropical rain forest soils in Puerto Rico are characterized by frequent anoxic conditions and fluctuating redox, suggesting the presence of lignin-degrading organisms and mechanisms that are different from known fungal decomposers and oxygen-dependent enzyme activities. We explored microbial lignin-degraders by burying bio-traps containing lignin-amended and unamended biosep beads in themore » soil for 1, 4, 13 and 30 weeks. At each time point, phenol oxidase and peroxidase enzyme activity was found to be elevated in the lignin-amended versus the unamended beads, while cellulolytic enzyme activities were significantly depressed in lignin-amended beads. Quantitative PCR of bacterial communities showed more bacterial colonization in the lignin-amended compared to the unamended beads after one and four weeks, suggesting that the lignin supported increased bacterial abundance. The microbial community was analyzed by small subunit 16S ribosomal RNA genes using microarray (PhyloChip) and by high-throughput amplicon pyrosequencing based on universal primers targeting bacterial, archaeal, and eukaryotic communities. Community trends were significantly affected by time and the presence of lignin on the beads. Lignin-amended beads have higher relative abundances of representatives from the phyla Actinobacteria, Firmicutes, Acidobacteria and Proteobacteria compared to unamended beads. This study suggests that in low and fluctuating redox soils, bacteria could play a role in anaerobic lignin decomposition.« less

Characterization of Trapped Lignin-Degrading Microbes in Tropical Forest Soil

PubMed Central

DeAngelis, Kristen M.; Allgaier, Martin; Chavarria, Yaucin; Fortney, Julian L.; Hugenholtz, Phillip; Simmons, Blake; Sublette, Kerry; Silver, Whendee L.; Hazen, Terry C.

2011-01-01

Lignin is often the most difficult portion of plant biomass to degrade, with fungi generally thought to dominate during late stage decomposition. Lignin in feedstock plant material represents a barrier to more efficient plant biomass conversion and can also hinder enzymatic access to cellulose, which is critical for biofuels production. Tropical rain forest soils in Puerto Rico are characterized by frequent anoxic conditions and fluctuating redox, suggesting the presence of lignin-degrading organisms and mechanisms that are different from known fungal decomposers and oxygen-dependent enzyme activities. We explored microbial lignin-degraders by burying bio-traps containing lignin-amended and unamended biosep beads in the soil for 1, 4, 13 and 30 weeks. At each time point, phenol oxidase and peroxidase enzyme activity was found to be elevated in the lignin-amended versus the unamended beads, while cellulolytic enzyme activities were significantly depressed in lignin-amended beads. Quantitative PCR of bacterial communities showed more bacterial colonization in the lignin-amended compared to the unamended beads after one and four weeks, suggesting that the lignin supported increased bacterial abundance. The microbial community was analyzed by small subunit 16S ribosomal RNA genes using microarray (PhyloChip) and by high-throughput amplicon pyrosequencing based on universal primers targeting bacterial, archaeal, and eukaryotic communities. Community trends were significantly affected by time and the presence of lignin on the beads. Lignin-amended beads have higher relative abundances of representatives from the phyla Actinobacteria, Firmicutes, Acidobacteria and Proteobacteria compared to unamended beads. This study suggests that in low and fluctuating redox soils, bacteria could play a role in anaerobic lignin decomposition. PMID:21559391

Critical soil bulk density for soybean growth in Oxisols

NASA Astrophysics Data System (ADS)

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

2015-10-01

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

Characterization of biosurfactants from indigenous soil bacteria recovered from oil contaminated sites.

PubMed

Kumar, Govind; Kumar, Rajesh; Sharma, Anita

2015-09-01

Three bacterial isolates (G1, G2 and G3) characterized as Pseudomonas plecoglossicida, Lysinibacillus fusiformis and Bacillus safensis were recovered from contaminated soil of oil refinery. These bacterial isolates produced biosurfactants in MSM medium in stationary phase. Biosurfactants were characterized on the basis of their emulsifying properties with petrol, diesel, mobil oil and petrol engine oil. Reduction in surface tension (below 40 mN m(-1)) and blood hemolysis were also included in biosurfactants characterization. Emulsification indices of G1, G2 and G3 were in the range of 98.82, 23.53 and 58.82 for petrol; 29.411,1.05 and 70.588 for diesel; 35.31, 2.93 and 17.60 for mobil oil and 35.284, 58.82 and 17.647 for petrol engine oil respectively. Dry weight of the extracted biosurfactant was 4.6, 1.4 and 2.4 g I(-1) for G1, G2 and G3 respectively. Structural analysis of the biosurfactants by Fourier Transform Infrared Spectroscopy (FTIR) revealed significant differences in the bonding pattern of individual biosurfactant.

Degradation and adsorption of tralkoxydim in Chinese soils and water-sediment environments.

PubMed

Wu, Wen Zhu; Shan, Zheng Jun; Kong, De Yang; He, Jian

2017-06-01

Tralkoxydim is a cyclohexanedione herbicide primarily used for gramineous weed control in China. In this paper, we present results of a tralkoxydim laboratory environmental fate study characterizing its degradation, adsorption, and mobility behavior in three different soils and two water-sediment systems (river and lake) in China. Degradation half-life of tralkoxydim in soil under aerobic conditions was 5.1, 7.7, and 7.9 days in Jiangxi red soil, Taihu paddy soil, and Northeast China black soil, respectively. Under anaerobic and flooding conditions, half-life values were 6.2, 15.1, and 19.8 days for the same three soils, respectively. Soil pH was the major factor effecting tralkoxydim degradation. In the aerobic water-sediment experiments, tralkoxydim degraded faster in the river system (total system half-life 43.3 days) than the lake system (total system half-life 99.0 days). Correspondingly, its anaerobic degradation half-life values were 46.2 and 53.3 days for the river and lake systems, respectively. Tralkoxydim adsorption in the three soils was found to follow the empirical Freundlich isotherm. The adsorption coefficient (K d ) was 8.60, 1.00, and 1.57 for Jiangxi red soil, Taihu paddy soil, and Northeast China black soil, respectively. Soil pH was the major factor effecting tralkoxydim adsorption. Adsorption free energy change was less than 40 kJ mol -1 in all three soils, indicating a physical mechanism in the process. Thin-layer chromatography (TLC) tests showed that relative to the solvent transport to 11.5 cm, the travel distance of tralkoxydim was 8-10 cm in the three soils, corresponding Rf values at 0.05, 0.35, and 0.75 for Jiangxi red soil, Taihu paddy soil, and Northeast China black soil, respectively. Results of this work suggest that under alkaline conditions, tralkoxydim adsorption becomes smaller; thus, assessments on its mobility and potential groundwater impact should focus on these soil types.

Spatial and temporal variability of soil hydraulic properties of topsoil affected by soil erosion

NASA Astrophysics Data System (ADS)

Nikodem, Antonin; Kodesova, Radka; Jaksik, Ondrej; Jirku, Veronika; Klement, Ales; Fer, Miroslav

2014-05-01

This study is focused on the comparison of soil hydraulic properties of topsoil that is affected by erosion processes. In order to include variable morphological and soil properties along the slope three sites - Brumovice, Vidim and Sedlčany were selected. Two transects (A, B) and five sampling sites along each one were chosen. Soil samples were taken in Brumovice after the tillage and sowing of winter wheat in October 2010 and after the wheat harvest in August 2011. At locality Vidim and Sedlčany samples were collected in May and August 2012. Soil hydraulic properties were studied in the laboratory on the undisturbed 100-cm3 soil samples placed in Tempe cells using the multi-step outflow test. Soil water retention data points were obtained by calculating water balance in the soil sample at each pressure head step of the experiment. The single-porosity model in HYDRUS-1D was applied to analyze the multi-step outflow and to obtain the parameters of soil hydraulic properties using the numerical inversion. The saturated hydraulic conductivities (Ks) and unsaturated hydraulic conductivities (Kw) for the pressure head of -2 cm of topsoil were also measured after the harvest using Guelph permeameter and Minidisk tensiometer, respectively. In general soil water retention curves measured before and after vegetation period apparently differed, which indicated soil material consolidation and soil-porous system rearrangement. Soil water retention curves obtained on the soil samples and hydraulic conductivities measured in the field reflected the position at the elevation transect and the effect of erosion/accumulation processes on soil structure and consequently on the soil hydraulic properties. The highest Ks values in Brumovice were obtained at the steepest parts of the elevation transects, that have been the most eroded. The Ks values at the bottom parts decreased due to the sedimentation of eroded soil particles. The change of the Kw values along transects didn't show

Mechanical impedance of soil crusts and water content in loamy soils

NASA Astrophysics Data System (ADS)

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

2013-04-01

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

Ecosystem-scale plant hydraulic strategies inferred from remotely-sensed soil moisture

NASA Astrophysics Data System (ADS)

Bassiouni, M.; Good, S. P.; Higgins, C. W.

2017-12-01

Characterizing plant hydraulic strategies at the ecosystem scale is important to improve estimates of evapotranspiration and to understand ecosystem productivity and resilience. However, quantifying plant hydraulic traits beyond the species level is a challenge. The probability density function of soil moisture observations provides key information about the soil moisture states at which evapotranspiration is reduced by water stress. Here, an inverse Bayesian approach is applied to a standard bucket model of soil column hydrology forced with stochastic precipitation inputs. Through this approach, we are able to determine the soil moisture thresholds at which stomata are open or closed that are most consistent with observed soil moisture probability density functions. This research utilizes remotely-sensed soil moisture data to explore global patterns of ecosystem-scale plant hydraulic strategies. Results are complementary to literature values of measured hydraulic traits of various species in different climates and previous estimates of ecosystem-scale plant isohydricity. The presented approach provides a novel relation between plant physiological behavior and soil-water dynamics.

Soil recovery across a chronosequence of restored wetlands in the Florida Everglades

NASA Astrophysics Data System (ADS)

Wang, Qibing; Li, Yuncong; Zhang, Min

2015-12-01

The restoration project in the Hole-in-the-Donut of Everglades National Park in Florida, USA is to reestablish native wetlands by complete removal of the invasive plants and the associated soil. However, there is little information available about changes in properties of the newly formed Marl soils in restored wetlands. In this study, we measured soil physicochemical properties, soil enzymatic activities, and stable isotopes of carbon (δ13C) in plants and soil organic carbon (SOC) in an undisturbed natural wetland (UNW) and three wetlands restored respectively in 1989, 1996 and 1999 (WR89, WR96 and WR99). The older restored wetlands (WR89 and WR96) are characterized by greater SOC and mineral nitrogen. The values of soil dehydrogenase and phosphatase activities in the four wetlands follow the order: UNW > WR89 > WR96 > WR99, and are consistent with changes in vegetation coverage. The principal component analysis shows that dehydrogenase and phosphatase activities are the vital variables contributing to the soil of UNW. The similar δ13C values of SOC and plants in the restored wetlands suggest the formation of SOC during restoration is mainly derived from the associated plants. These results indicate that the newly restored soils develop toward the soil in the UNW with time since restoration.

Soil recovery across a chronosequence of restored wetlands in the Florida Everglades.

PubMed

Wang, Qibing; Li, Yuncong; Zhang, Min

2015-12-01

The restoration project in the Hole-in-the-Donut of Everglades National Park in Florida, USA is to reestablish native wetlands by complete removal of the invasive plants and the associated soil. However, there is little information available about changes in properties of the newly formed Marl soils in restored wetlands. In this study, we measured soil physicochemical properties, soil enzymatic activities, and stable isotopes of carbon (δ(13)C) in plants and soil organic carbon (SOC) in an undisturbed natural wetland (UNW) and three wetlands restored respectively in 1989, 1996 and 1999 (WR89, WR96 and WR99). The older restored wetlands (WR89 and WR96) are characterized by greater SOC and mineral nitrogen. The values of soil dehydrogenase and phosphatase activities in the four wetlands follow the order: UNW > WR89 > WR96 > WR99, and are consistent with changes in vegetation coverage. The principal component analysis shows that dehydrogenase and phosphatase activities are the vital variables contributing to the soil of UNW. The similar δ(13)C values of SOC and plants in the restored wetlands suggest the formation of SOC during restoration is mainly derived from the associated plants. These results indicate that the newly restored soils develop toward the soil in the UNW with time since restoration.

Influence of soil moisture on soil respiration

NASA Astrophysics Data System (ADS)

Fer, Miroslav; Kodesova, Radka; Nikodem, Antonin; Klement, Ales; Jelenova, Klara

2015-04-01

The aim of this work was to describe an impact of soil moisture on soil respiration. Study was performed on soil samples from morphologically diverse study site in loess region of Southern Moravia, Czech Republic. The original soil type is Haplic Chernozem, which was due to erosion changed into Regosol (steep parts) and Colluvial soil (base slope and the tributary valley). Soil samples were collected from topsoils at 5 points of the selected elevation transect and also from the parent material (loess). Grab soil samples, undisturbed soil samples (small - 100 cm3, and large - 713 cm3) and undisturbed soil blocks were taken. Basic soil properties were determined on grab soil samples. Small undisturbed soil samples were used to determine the soil water retention curves and the hydraulic conductivity functions using the multiple outflow tests in Tempe cells and a numerical inversion with HYDRUS 1-D. During experiments performed in greenhouse dry large undisturbed soil samples were wetted from below using a kaolin tank and cumulative water inflow due to capillary rise was measured. Simultaneously net CO2 exchange rate and net H2O exchange rate were measured using LCi-SD portable photosynthesis system with Soil Respiration Chamber. Numerical inversion of the measured cumulative capillary rise data using the HYDRUS-1D program was applied to modify selected soil hydraulic parameters for particular conditions and to simulate actual soil water distribution within each soil column in selected times. Undisturbed soil blocks were used to prepare thin soil sections to study soil-pore structure. Results for all soil samples showed that at the beginning of soil samples wetting the CO2 emission increased because of improving condition for microbes' activity. The maximum values were reached for soil column average soil water content between 0.10 and 0.15 cm3/cm3. Next CO2 emission decreased since the pore system starts filling by water (i.e. aggravated conditions for microbes

Extraction and characterization of ternary complexes between natural organic matter, cations, and oxyanions from a natural soil.

PubMed

Peel, Hannah R; Martin, David P; Bednar, Anthony J

2017-06-01

Natural organic matter (NOM) can have a significant influence on the mobility and fate of inorganic oxyanions, such as arsenic and selenium, in the environment. There is evidence to suggest that interactions between NOM and these oxyanions are facilitated by bridging cations (primarily Fe 3+ ) through the formation of ternary complexes. Building on previous work characterizing ternary complexes formed in the laboratory using purified NOM, this study describes the extraction and characterization of intact ternary complexes directly from a soil matrix. The complexes are stable to the basic extraction conditions (pH 12) and do not appear to change when the pH of the extract is adjusted back to neutral. The results suggest that ternary complexes between NOM, cations, and inorganic oxyanions exist in natural soils and could play a role in the speciation of inorganic oxyanions in environmental matrices. Published by Elsevier Ltd.

Using rainfall simulations to understand the relationship between precipitation, soil crust and infiltration in four agricultural soils

NASA Astrophysics Data System (ADS)

Angulo-Martinez, Marta; Alastrué, Juan; Moret-Fernández, David; Beguería, Santiago; López, Mariví; Navas, Ana

2017-04-01

Rainfall simulation experiments were carried out in order to study soil crust formation and its relation with soil infiltration parameters—sorptivity (S) and hydraulic conductivity (K)—on four common agricultural soils with contrasted properties; namely, Cambisol, Gypsisol, Solonchak, and Solonetz. Three different rainfall simulations, replicated three times each of them, were performed over the soils. Prior to rainfall simulations all soils were mechanically tilled with a rototiller to create similar soil surface conditions and homogeneous soils. Rainfall simulation parameters were monitored in real time by a Thies Laser Precipitation Monitor, allowing a complete characterization of simulated rainfall microphysics (drop size and velocity distributions) and integrated variables (accumulated rainfall, intensity and kinetic energy). Once soils dried after the simulations, soil penetration resistance was measured and soil hydraulic parameters, S and K, were estimated using the disc infiltrometry technique. There was little variation in rainfall parameters among simulations. Mean intensity and mean median diameter (D50) varied in simulations 1 ( 0.5 bar), 2 ( 0.8 bar) and 3 ( 1.2 bar) from 26.5 mm h-1 and 0.43 mm (s1) to 40.5 mm h-1 and 0.54 mm (s2) and 41.1 mm h-1 and 0.56 mm for (s3), respectively. Crust formation by soil was explained by D50 and subsequently by the total precipitation amount and the percentage of silt and clay in soil, being Cambisol and Gypsisol the soils that showed more increase in penetration resistance by simulation. All soils showed similar S values by simulations which were explained by rainfall intensity. Different patterns of K were shown by the four soils, which were explained by the combined effect of D50 and intensity, together with soil physico-chemical properties. This study highlights the importance of monitoring all precipitation parameters to determine their effect on different soil processes.

Thermoregulatory value of cracking-clay soil shelters for small vertebrates during extreme desert conditions.

PubMed

Waudby, Helen P; Petit, Sophie

2017-05-01

Deserts exhibit extreme climatic conditions. Small desert-dwelling vertebrates have physiological and behavioral adaptations to cope with these conditions, including the ability to seek shelter. We investigated the temperature (T) and relative humidity (RH) regulating properties of the soil cracks that characterize the extensive cracking-clay landscapes of arid Australia, and the extent of their use by 2 small marsupial species: fat-tailed and stripe-faced dunnarts (Sminthopsis crassicaudata and Sminthopsis macroura). We measured hourly (over 24-h periods) the T and RH of randomly-selected soil cracks compared to outside conditions, during 2 summers and 2 winters. We tracked 17 dunnarts (8 Sminthopsis crassicaudata and 9 Sminthopsis macroura) to quantify their use of cracks. Cracks consistently moderated microclimate, providing more stable conditions than available from non-crack points, which often displayed comparatively dramatic fluctuations in T and RH. Both dunnart species used crack shelters extensively. Cracks constitute important shelter for small animals during extreme conditions by providing a stable microclimate, which is typically cooler than outside conditions in summer and warmer in winter. Cracks likely play a fundamental sheltering role by sustaining the physiological needs of small mammal populations. Globally, cracking-clay areas are dominated by agricultural land uses, including livestock grazing. Management of these systems should focus not only on vegetation condition, but also on soil integrity, to maintain shelter resources for ground-dwelling fauna. © 2016 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

Properties of Subsurface Soil Cores from Four Geologic Provinces Surrounding Mars Desert Research Station, Utah: Characterizing Analog Martian Soil in a Human Exploration Scenario

NASA Technical Reports Server (NTRS)

Stoker, C. R.; Clarke, J. D. A.; Direito, S.; Foing, B.

2011-01-01

The DOMEX program is a NASA-MMAMA funded project featuring simulations of human crews on Mars focused on science activities that involve collecting samples from the subsurface using both manual and robotic equipment methods and analyzing them in the field and post mission. A crew simulating a human mission to Mars performed activities focused on subsurface science for 2 weeks in November 2009 at Mars Desert Research Station near Hanksville, Utah --an important chemical and morphological Mars analog site. Activities performed included 1) survey of the area to identify geologic provinces, 2) obtaining soil and rock samples from each province and characterizing their mineralogy, chemistry, and biology; 3) site selection and reconnaissance for a future drilling mission; 4) deployment and testing of Mars Underground Mole, a percussive robotic soil sampling device; and 5) recording and analyzing how crew time was used to accomplish these tasks. This paper summarizes results from analysis of soil cores

Soil carbon storage estimation in a forested watershed using quantitative soil-landscape modeling

Treesearch

James A. Thompson; Randall K. Kolka

2005-01-01

Carbon storage in soils is important to forest ecosystems. Moreover, forest soils may serve as important C sinks for ameliorating excess atmospheric CO2. Spatial estimates of soil organic C (SOC) storage have traditionally relied upon soil survey maps and laboratory characterization data. This approach does not account for inherent variability...

Factors of soil diversity in the Batumi delta (Georgia)

NASA Astrophysics Data System (ADS)

Turgut, Bülent; Ateş, Merve

2017-01-01

The aim of this study was to determine certain basic properties of soils in the Batumi delta (southwestern Georgia) to determine the relationships of studied properties and to identify differences with regards to these properties between different sampling sites in the delta that were selected based on the delta morphology. In this context, a total of 125 soil samples were collected from five different sampling sites, and the clay, silt and sand content of the samples were determined along with their mean weight diameter (MWD) values, aggregate stability (AS) values, amount of water retained under -33 (FC) and -1500 kPa (WP) pressure and organic matter (OM) content. Correlation analysis indicated that clay content and OM were positively correlated with MWD, and OM was positively correlated with AS. However, the sand content was found to be negatively correlated with MWD. In addition, clay, silt and OM content were positive correlated with FC and WP. Variance analysis results determined statistically significant differences between the sampling sites with respect to all of the evaluated properties. The active delta section of the study area was characterized by high sand content, while the lower delta plain was characterized by high OM and AS values, and the upper delta plain was characterized by high MWD values, high FC and WP moisture content levels and high clay and silt content. In conclusion, it was demonstrated that the examined properties were significantly affected by the different morphological positions and usages of these different areas. These results may help with the management of agricultural lands in the Batumi delta, which has never been studied before.

Characterizations of matrix and operator-valued Φ-entropies, and operator Efron-Stein inequalities.

PubMed

Cheng, Hao-Chung; Hsieh, Min-Hsiu

2016-03-01

We derive new characterizations of the matrix Φ-entropy functionals introduced in Chen & Tropp (Chen, Tropp 2014 Electron. J. Prob. 19 , 1-30. (doi:10.1214/ejp.v19-2964)). These characterizations help us to better understand the properties of matrix Φ-entropies, and are a powerful tool for establishing matrix concentration inequalities for random matrices. Then, we propose an operator-valued generalization of matrix Φ-entropy functionals, and prove the subadditivity under Löwner partial ordering. Our results demonstrate that the subadditivity of operator-valued Φ-entropies is equivalent to the convexity. As an application, we derive the operator Efron-Stein inequality.

Characterizations of matrix and operator-valued Φ-entropies, and operator Efron–Stein inequalities

PubMed Central

Cheng, Hao-Chung; Hsieh, Min-Hsiu

2016-01-01

We derive new characterizations of the matrix Φ-entropy functionals introduced in Chen & Tropp (Chen, Tropp 2014 Electron. J. Prob. 19, 1–30. (doi:10.1214/ejp.v19-2964)). These characterizations help us to better understand the properties of matrix Φ-entropies, and are a powerful tool for establishing matrix concentration inequalities for random matrices. Then, we propose an operator-valued generalization of matrix Φ-entropy functionals, and prove the subadditivity under Löwner partial ordering. Our results demonstrate that the subadditivity of operator-valued Φ-entropies is equivalent to the convexity. As an application, we derive the operator Efron–Stein inequality. PMID:27118909

Soil magnetic susceptibility reflects soil moisture regimes and the adaptability of tree species to these regimes

USGS Publications Warehouse

Wang, J.-S.; Grimley, D.A.; Xu, C.; Dawson, J.O.

2008-01-01

Flooded, saturated or poorly drained soils are frequently anaerobic, leading to dissolution of the strongly magnetic minerals, magnetite and maghemite, and a corresponding decrease in soil magnetic susceptibility (MS). In this study of five temperate deciduous forests in east-central Illinois, USA, mean surface soil MS was significantly higher adjacent to upland tree species (31 ?? 10-5 SI) than adjacent to floodplain or lowland tree species (17 ?? 10-5 SI), when comparing regional soils with similar parent material of loessal silt. Although the sites differ in average soil MS for each tree species, the relative order of soil MS means for associated tree species at different locations is similar. Lowland tree species, Celtis occidentalis L., Ulmus americana L., Acer saccharinum L., Carya laciniosa (Michx. f.) Loud., and Fraxinus pennsylvanica Marsh. were associated with the lowest measured soil MS mean values overall and at each site. Tree species' flood tolerance rankings increased significantly, as soil MS values declined, the published rankings having significant correlations with soil MS values for the same species groups. The three published classifications of tree species' flood tolerance were significantly correlated with associated soil MS values at all sites, but most strongly at Allerton Park, the site with the widest range of soil drainage classes and MS values. Using soil MS measurements in forests with soil parent material containing similar initial levels of strongly magnetic minerals can provide a simple, rapid and quantitative method to classify soils according to hydric regimes, including dry conditions, and associated plant composition. Soil MS values thus have the capacity to quantify the continuum of hydric tolerances of tree species and guide tree species selection for reforestation. ?? 2007 Elsevier B.V. All rights reserved.

Characterization of extractable soil organic matter pools from African Dark Earths (AfDE): A case study in historical biochar and organic waste amendments

NASA Astrophysics Data System (ADS)

Fujiu, Manna; Plante, Alain; Ohno, Tsutomu; Solomon, Dawit; Lehmann, Johannes; Fraser, James; Leach, Melissa; Fairhead, James

2014-05-01

Anthropogenic Dark Earths are soils generated through long-term human inputs of organic and pyrogenic materials. These soils were originally discovered in the Amazon, and have since been found in Australia and in this case in Africa. African Dark Earths (AfDE) are black, highly fertile and carbon-rich soils that were formed from the original highly-weathered infertile yellowish to red Oxisols and Ultisols through an extant but hitherto overlooked climate-smart sustainable soil management system that has long been an important feature of the indigenous West African agricultural repertoire. Studies have demonstrated that ADE soils in general have significantly different organic matter properties compared to adjacent non-DE soils, largely attributable to the presence of high concentrations of ash-derived carbon. Quantification and characterization of bulk soil organic matter of several (n=11) AfDE and non-AfDE pairs of surface (0-15 cm) soils using thermal analysis techniques (TG-DSC-EGA) confirmed substantial differences in SOM composition and the presence of pyrogenic C. Such pyrogenic organic matter is generally considered recalcitrant or relatively stable, but the goal of the current study was to characterize the presumably labile, more rapidly cycling, pools of C in AfDEs through the characterization of hot water- and pyrophosphate-extractable fractions, referred to as HWEOC and PyroC respectively. Extracts were analyzed for carbon content, as well as composition using fluorescence (EEM/PARAFAC) and high resolution mass spectrometry (FTICR-MS). The amount of extractable C as a proportion of total soil C was relatively low: less than ~0.8% for HWEOC and 2.8% for PyroC. The proportion of HWEOC did not differ (P = 0.18, paired t-test) between the AfDE and the non-AfDE soils, while the proportions of PyroC were significantly larger (P = 0.001) in the AfDE soils compared to the non-AfDE soils. Preliminary analysis of the EEM/PARAFAC data suggests that AfDE samples had

Micromorphological Aspects of Forensic Geopedology II: Ultramicroscopic vs Microscopic Characterization of Phosphatic Impregnations on Soil Particles in Experimental Burials

NASA Astrophysics Data System (ADS)

Ern, S. I. E.; Trombino, L.; Cattaneo, C.

2012-04-01

Grows up the importance of the role played by soil scientists in the modern forensic sciences, in particular when buried human remains strongly decomposed or skeletonized are found in different environment situations. Among the different techniques normally used in geopedology, it is usefull to apply in such forensic cases, soil micromorphology (including optical microscopy and ultramicroscopy) that has been underused up today, for various kind of reasons. An interdisciplinary Italian-team, formed by earth scientists and legal medicine, is working on several sets of experimental burial of pigs and piglets in different soil types and for different times of burial, in order to get new evidences on environmental behaviour related to the burial, focalising on geopedological and micropedological aspects. The present work is focused on: - ultramicroscopic (SEM-EDS) characterization of the phosphatic impregnation (by body fluids) on soils sampled under the dead bodies of five couples of pigs, buried respectively for one month, six month, one year, two years and two years and half in two different areas; - microscopic (petrographic microscope) and ultramicroscopic (SEM-EDS) cross characterization of the phosphatic impregnation (by body fluids) on soils sampled under the dead bodies of several piglets, buried for twenty months. The first results show trends of persistency of such phosphatic features, mainly related to the grain size of the impregnated soil particles and weather conditions (or seasons) of exhumation, while apparently time since burial is only marginally effective for the investigated burial period. Further experiments are in progress in order to clarify the pathways of phosphorus precipitation and leaching for longer times of burial and different seasons of exhumation, both from the microscopic and the pedological/chemical point of view.

Medusahead: Available soil N and microbial communities in native and invasive soils

Treesearch

Robert R. Blank; Rene Sforza; Tye Morgan

2008-01-01

To better understand why medusahead (Taeniatherum caput-medusae) is invasive, we quantified soil N availability and characterized soil microbial communities between native and invasive populations. No consistent differences in soil N mineralization potentials were noted between native medusahead sites in Spain, Turkey, France, and Greece and two...

A Lipid Extraction and Analysis Method for Characterizing Soil Microbes in Experiments with Many Samples

PubMed Central

Oates, Lawrence G.; Read, Harry W.; Gutknecht, Jessica L. M.; Duncan, David S.; Balser, Teri B.; Jackson, Randall D.

2017-01-01

Microbial communities are important drivers and regulators of ecosystem processes. To understand how management of ecosystems may affect microbial communities, a relatively precise but effort-intensive technique to assay microbial community composition is phospholipid fatty acid (PLFA) analysis. PLFA was developed to analyze phospholipid biomarkers, which can be used as indicators of microbial biomass and the composition of broad functional groups of fungi and bacteria. It has commonly been used to compare soils under alternative plant communities, ecology, and management regimes. The PLFA method has been shown to be sensitive to detecting shifts in microbial community composition. An alternative method, fatty acid methyl ester extraction and analysis (MIDI-FA) was developed for rapid extraction of total lipids, without separation of the phospholipid fraction, from pure cultures as a microbial identification technique. This method is rapid but is less suited for soil samples because it lacks an initial step separating soil particles and begins instead with a saponification reaction that likely produces artifacts from the background organic matter in the soil. This article describes a method that increases throughput while balancing effort and accuracy for extraction of lipids from the cell membranes of microorganisms for use in characterizing both total lipids and the relative abundance of indicator lipids to determine soil microbial community structure in studies with many samples. The method combines the accuracy achieved through PLFA profiling by extracting and concentrating soil lipids as a first step, and a reduction in effort by saponifying the organic material extracted and processing with the MIDI-FA method as a second step. PMID:28745639

Characterizing effects of wind erosion on soil microtopography in a semiarid grassland using terrestrial laser scanning

NASA Astrophysics Data System (ADS)

Li, J.; Washington-Allen, R. A.; Okin, G. S.

2010-12-01

Aeolian processes play important roles in microtopography and associated soil-plant interactions in arid and semiarid landscapes. Most previous research has focused on scales larger than plant-interspaces and the dynamics of “fertile islands” associated with individual shrubs. Arid and semiarid ecosystems are notoriously heterogeneous in both microtopography and soil nutrients, and investigations of soil topography and plant-soil interactions at much finer scales (e.g., a few millimeters) are difficult using traditional point based sampling methods. Terrestrial laser scanners (TLS) are novel tools for which techniques can be developed to accurately characterize micro-scale topography with a spot diameter of 4.5 mm, and 2 mm ranging accuracy at 50 kHz. In this study, we employed a portable TLS (a Leica ScanStation 2) to digitally capture the 3-dimensional soil microtopography in a Chihuahuan desert grassland located in southern New Mexico. Soil surface on this site had been exposed to enhanced wind erosion since the spring of 2004. A control plot, located adjacent to the wind erosion plot, was also scanned to provide soil microtopography bench mark. A nearest neighbor interpolation was used on the elevation point clouds to yield bare ground, vegetation, and combined digital surface models for both plots. Additionally, measures of height and foliage diversity, vegetation and bare ground cover, and surface roughness were calculated. The results from this field study clearly demonstrate that TLS can provide insights on changes in microtopography affected by aeolian processes. Moreover, within the known distribution of soil nutrients, the 3D surface model of the soil microtopography provided unprecedented detail on the distribution of “mini” fertile islands associated with topography that were not revealed by studies at plant-interspace scale.

Resolving inter-annual terrestrial water storage variations using microwave-based surface soil moisture retrievals

USDA-ARS?s Scientific Manuscript database

Due to their shallow vertical support, remotely-sensed surface soil moisture retrievals are commonly regarded as being of limited value for water budget applications requiring the characterization of temporal variations in total terrestrial water storage (S). However, advances in our ability to esti...

The Biotoxicity of Mars Soils

NASA Technical Reports Server (NTRS)

Kerney, Krystal

2010-01-01

Recent evidence from the Opportunity and Spirit rovers suggests that the soils on Mars might be very high in biotoxic materials induding sulfate salts, chlorides, and acidifying agents. Yet, very little is known about how the chemistries of Mars soils might affect the survival and growth of terrestrial microorganisms. The primary objectives of the proposed research will be to: (1) prepare and characterize Mars analog soils amended with potential biotoxic levels of sulfates, chlorides, and acidifying minerals; (2) use the stimulants to conduct a series of toxicology assays to determine if terrestrial microorganisms from spacecraft or extreme environments can survive direct exposure to the biotoxic soils, and (3) mix soils from extreme environments on Earth into Mars analog soils to determine if terrestrial microorganisms can grow and replicate under Martian conditions. The Mars analog soils will be thoroughly characterized by a wide diversity of soil chemistry assays to determine the exact nature of the soluble biotoxic components following hydration. The microbial experiments will be designed to test the effects of Mars stimulants on microbial survival, growth and replication during direct challenge experiments. Toxicology experiments will be designed to mimic terrestrial microbes coming into contact with biotoxic soils with and without liquid water. Results are expected to help" ... characterize the limits of life in ... planetary environments ... " and may help constrain the search for life on Mars.

Characterization of soil fauna under the influence of mercury atmospheric deposition in Atlantic Forest, Rio de Janeiro, Brazil.

PubMed

Buch, Andressa Cristhy; Correia, Maria Elizabeth Fernandes; Teixeira, Daniel Cabral; Silva-Filho, Emmanoel Vieira

2015-06-01

The increasing levels of mercury (Hg) found in the atmosphere arising from anthropogenic sources, have been the object of great concern in the past two decades in industrialized countries. Brazil is the seventh country with the highest rate of mercury in the atmosphere. The major input of Hg to ecosystems is through atmospheric deposition (wet and dry), being transported in the atmosphere over large distances. The forest biomes are of strong importance in the atmosphere/soil cycling of elemental Hg through foliar uptake and subsequent transference to the soil through litter, playing an important role as sink of this element. Soil microarthropods are keys to understanding the soil ecosystem, and for such purpose were characterized by the soil fauna of two Units of Forest Conservation of the state of the Rio de Janeiro, inwhich one of the areas suffer quite interference from petrochemicals and industrial anthropogenic activities and other area almost exempts of these perturbations. The results showed that soil and litter of the Atlantic Forest in Brazil tend to stock high mercury concentrations, which could affect the abundance and richness of soil fauna, endangering its biodiversity and thereby the functioning of ecosystems. Copyright © 2015. Published by Elsevier B.V.

Advanced solvent based methods for molecular characterization of soil organic matter by high-resolution mass spectrometry

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

Tfaily, Malak M.; Chu, Rosalie K.; Tolic, Nikola

2015-05-19

Soil organic matter (SOM) a complex, heterogeneous mixture of above and belowground plant litter and animal and microbial residues at various degrees of decomposition, is a key reservoir for carbon (C) and nutrient biogeochemical cycling in soil based ecosystems. A limited understanding of the molecular composition of SOM limits the ability to routinely decipher chemical processes within soil and predict accurately how terrestrial carbon fluxes will response to changing climatic conditions and land use. To elucidate the molecular-level structure of SOM, we selectively extracted a broad range of intact SOM compounds by a combination of different organic solvents from soilsmore » with a wide range of C content. Our use of Electrospray ionization (ESI) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) and a suite of solvents with varying polarity significantly expands the inventory of the types of organic molecules present in soils. Specifically, we found that hexane is selective for lipid-like compounds with very low O:C ratios; water was selective for carbohydrates with high O:C ratios; acetonitrile preferentially extracts lignin, condensed structures, and tannin poly phenolic compounds with O:C > 0.5; methanol has higher selectivity towards compounds characterized with low O:C < 0.5; and hexane, MeOH, ACN and water solvents increase the number and types of organic molecules extracted from soil for a broader range of chemically diverse soil types. Our study of SOM molecules by ESI-FTICR MS revealed new insight into the molecular-level complexity of organics contained in soils.« less

Contribution of soil fauna to soil functioning in degraded environments: a multidisciplinary approach

NASA Astrophysics Data System (ADS)

Gargiulo, Laura; Mele, Giacomo; Moradi, Jabbar; Kukla, Jaroslav; Jandová, Kateřina; Frouz, Jan

2016-04-01

The restoration of the soil functions is essential for the recovery of highly degraded sites and, consequently, the study of the soil fauna role in the soil development in such environments has great potential from a practical point of view. The soils of the post-mining sites represent unique models for the study of the natural ecological succession because mining creates similar environments characterized by the same substrate, but by different ages according to the year of closure of mines. The aim of this work was to assess the contribution of different species of macrofauna on the evolution of soil structure and on the composition and activity of the microbial community in soil samples subjected to ecological restoration or characterized by spontaneous ecological succession. For this purpose, an experimental test was carried out in two sites characterized by different post-mining conditions: 1) natural succession, 2) reclamation with planting trees. These sites are located in the post-mining area of Sokolov (Czech Republic). For the experimental test repacked soil cores were prepared in laboratory with sieved soil sampled from the two sites. The soil cores were prepared maintaining the sequence of soil horizons present in the field. These samples were inoculated separately with two genera of earthworms (Lumbricus and Aporrectodea) and two of centipedes (Julida and Polydesmus). In particular, based on their body size, were inoculated for each cylinder 2 individuals of millipedes, 1 individual of Lumbricus and 4 individuals of Aporrectodea. For each treatment and for control samples 5 replicates were prepared and all samples were incubated in field for 1 month in the two original sampling sites. After the incubation the samples were removed from the field and transported in laboratory in order to perform the analysis of microbial respiration, of PLFA (phospholipid-derived fatty acids) and ergosterol contents and finally for the characterization of soil structure

Standard Operating Procedure for Using the NAFTA Guidance to Calculate Representative Half-life Values and Characterizing Pesticide Degradation

EPA Pesticide Factsheets

Results of the degradation kinetics project and describes a general approach for calculating and selecting representative half-life values from soil and aquatic transformation studies for risk assessment and exposure modeling purposes.

Impact of set-aside management on soil mesofauna

NASA Astrophysics Data System (ADS)

Landi, Silvia; d'Errico, Giada; Mazza, Giuseppe; Mocali, Stefano; Bazzoffi, Paolo; Roversi, Pio Federico

2014-05-01

(MI) resulted significantly higher in set-aside managements than in conventional crops in Fagna and Metaponto sites. In contrast, Caorle was characterized by a significant soil degradation (prevalence of extreme colonizers) and any increase of MI values in the set-aside have been not detected. About microarthropods, the taxa richness was significantly higher in set-aside managements than conventional crops in all the sites sampled. QBS index showed the same trend, but the differences were not significant. Caorle site was characterized by a lack of balance in the relative abundance among soil microarthropods taxa. In particular, set-aside managements showed a strong prevalence of an aggressive ants Solenopsis fugax (Hymenoptera: Formicidae). In conclusion, the best results were observed in Fagna and Metaponto sites, where MI and QBS values increased under set-aside management as compared to the conventional. Further analyses will be carried out over a long period to better understand the possible correlation between the enhancement of the organic matter observed in the soils less degraded and the biological quality improvement.

Distribution of tetraether lipids in agricultural soils - differentiation between paddy and upland management

NASA Astrophysics Data System (ADS)

Mueller-Niggemann, Cornelia; Rahayu Utami, Sri; Marxen, Anika; Mangelsdorf, Kai; Bauersachs, Thorsten; Schwark, Lorenz

2016-03-01

Rice paddies constitute almost a fifth of global cropland and provide more than half of the world's population with staple food. At the same time, they are a major source of methane and therewith significantly contribute to the current warming of Earth's atmosphere. Despite their apparent importance in the cycling of carbon and other elements, however, the microorganisms thriving in rice paddies are insufficiently characterized with respect to their biomolecules. Hardly any information exists on human-induced alteration of biomolecules from natural microbial communities in paddy soils through varying management types (affecting, e.g., soil or water redox conditions, cultivated plants). Here, we determined the influence of different land use types on the distribution of glycerol dialkyl glycerol tetraethers (GDGTs), which serve as molecular indicators for microbial community structures, in rice paddy (periodically flooded) and adjacent upland (non-flooded) soils and, for further comparison, forest, bushland and marsh soils. To differentiate local effects on GDGT distribution patterns, we collected soil samples in locations from tropical (Indonesia, Vietnam and Philippines) and subtropical (China and Italy) sites. We found that differences in the distribution of isoprenoid GDGTs (iGDGTs) as well as of branched GDGTs (brGDGTs) are predominantly controlled by management type and only secondarily by climatic exposition. In general, upland soil had higher crenarchaeol contents than paddy soil, which by contrast was more enriched in GDGT-0. The GDGT-0 / crenarchaeol ratio, indicating the enhanced presence of methanogenic archaea, was 3-27 times higher in paddy soils compared to other soils and increased with the number of rice cultivation cycles per year. The index of tetraethers consisting of 86 carbons (TEX86) values were 1.3 times higher in upland, bushland and forest soils than in paddy soils, potentially due to differences in soil temperature. In all soils br

Bioelectric potentials in the soil-plant system

NASA Astrophysics Data System (ADS)

Pozdnyakov, A. I.

2013-07-01

A detailed study of the electric potentials in the soil-plant system was performed. It was found that the electric potential depends on the plant species and the soil properties. A theoretical interpretation of the obtained data was given. All the plants, independently from their species and their state, always had a negative electric potential relative to the soil. The electric potential of the herbaceous plants largely depended on the leaf area. In some plants, such as burdock ( Arctium lappa) and hogweed ( Heracleum sosnowskyi), the absolute values of the negative electric potential exceeded 100 mV. The electric potential was clearly differentiated by the plant organs: in the flowers, it was lower than in the leaves; in the leaves, it was usually lower than in the leaf rosettes and stems. The electric potentials displayed seasonal dynamics. As a rule, the higher the soil water content, the lower the electric potential of the plants. However, an inverse relationship was observed for dandelions ( Taraxacum officinale). It can be supposed that the electric potential between the soil and the plant characterizes the vital energy of the plant.

Comparison of ion-exchange resin counterions in the nutrient measurement of calcareous soils: Implications for correlative studies of plant-soil relationships

USGS Publications Warehouse

Sherrod, S.K.; Belnap, J.; Miller, M.E.

2003-01-01

For more than 40 years, ion-exchange resins have been used to characterize nutrient bioavailability in terrestrial and aquatic ecosystems. To date, however, no standardized methodology has been developed, particularly with respect to the counterions that initially occupy resin exchange sites. To determine whether different resin counterions yield different measures of soil nutrients and rank soils differently with respect to their measured nutrient bioavailability, we compared nutrient measurements by three common counterion combinations (HCl, HOH, and NaHCO3). Five sandy calcareous soils were chosen to represent a range of soil characteristics at Canyonlands National Park, Utah, and resin capsules charged with the different counterions equilibrated in saturated pastes of these soils for one week. Data were converted to proportions of total ions of corresponding charge for ANOVA. Results from the different methods were not comparable with respect to any nutrient. Of eleven nutrients measured, all but iron (Fe2+), manganese (Mn2+), and zinc (Zn2+) differed significantly (p ??? 0.05) as a function of soil x counterion interactions; Fe2+ and Zn2+ varied as functions of counterion alone. Of the counterion combinations, HCl-resins yielded the most net ion exchange with all measured nutrients except Na+, NH4+, and HPO42-, the three of which desorbed in the greatest quantities from HOH-resins. Conventional chemical extractions using ammonium acetate generally yielded high proportional values of Ca2+, K+, and Na+. Further, among-soil rankings of nutrient bioavailability varied widely among methods. This study highlights the fact that various ion-exchange resin techniques for measuring soil nutrients may have differential effects on the soil-resin environment and yield data that should not be compared nor considered interchangeable. The most appropriate methods for characterizing soil-nutrient bioavailability depends on soil characteristics and likely on the physiological

Characterization of Growing Soil Bacterial Communities across a pH gradient Using H218O DNA-Stable Isotope Probing

NASA Astrophysics Data System (ADS)

Welty-Bernard, A. T.; Schwartz, E.

2014-12-01

Recent studies have established consistent relationships between pH and bacterial diversity and community structure in soils from site-specific to landscape scales. However, these studies rely on DNA or PLFA extraction techniques from bulk soils that encompass metabolically active and inactive, or dormant, communities, and loose DNA. Dormant cells may comprise up to 80% of total live cells. If dormant cells dominate a particular environment, it is possible that previous interpretations of the soil variables assumed to drive communities could be profoundly affected. We used H218O stable isotope probing and bar-coded illumina sequencing of 16S rRNA genes to monitor the response of actively growing communities to changes in soil pH in a soil microcosm over 14 days. This substrate-independent approach has several advantages over 13C or 15N-labelled molecules in that all growing bacteria should be able to make use of water, allowing characterization of whole communities. We hypothesized that Acidobacteria would increasingly dominate the growing community and that Actinobacteria and Bacteroidetes would decline, given previously established responses by these taxa to soil pH. Instead, we observed the reverse. Actinobacteria abundance increased three-fold from 26 to 76% of the overall community as soil pH fell from pH 5.6 to pH 4.6. Shifts in community structure and decreases in diversity with declining soil pH were essentially driven by two families, Streptomyceaca and Microbacteracea, which collectively increased from 2 to 40% of the entire community. In contrast, Acidobacteria as a whole declined although numbers of subdivision 1 remained stable across all soil pH levels. We suggest that the brief incubation period in this SIP study selected for growth of acid-tolerant Actinobacteria over Acidobacteria. Taxa within Actinomycetales have been readily cultured over short time frames, suggesting rapid growth patterns. Conversely, taxa within Acidobacteria have been

Nitrogen cycling in an extreme hyperarid environment inferred from δ(15)N analyses of plants, soils and herbivore diet.

PubMed

Díaz, Francisca P; Frugone, Matías; Gutiérrez, Rodrigo A; Latorre, Claudio

2016-03-09

Climate controls on the nitrogen cycle are suggested by the negative correlation between precipitation and δ(15)N values across different ecosystems. For arid ecosystems this is unclear, as water limitation among other factors can confound this relationship. We measured herbivore feces, foliar and soil δ(15)N and δ(13)C values and chemically characterized soils (pH and elemental composition) along an elevational/climatic gradient in the Atacama Desert, northern Chile. Although very positive δ(15)N values span the entire gradient, soil δ(15)N values show a positive correlation with aridity as expected. In contrast, foliar δ(15)N values and herbivore feces show a hump-shaped relationship with elevation, suggesting that plants are using a different N source, possibly of biotic origin. Thus at the extreme limits of plant life, biotic interactions may be just as important as abiotic processes, such as climate in explaining ecosystem δ(15)N values.

Nitrogen cycling in an extreme hyperarid environment inferred from δ15N analyses of plants, soils and herbivore diet

NASA Astrophysics Data System (ADS)

Díaz, Francisca P.; Frugone, Matías; Gutiérrez, Rodrigo A.; Latorre, Claudio

2016-03-01

Climate controls on the nitrogen cycle are suggested by the negative correlation between precipitation and δ15N values across different ecosystems. For arid ecosystems this is unclear, as water limitation among other factors can confound this relationship. We measured herbivore feces, foliar and soil δ15N and δ13C values and chemically characterized soils (pH and elemental composition) along an elevational/climatic gradient in the Atacama Desert, northern Chile. Although very positive δ15N values span the entire gradient, soil δ15N values show a positive correlation with aridity as expected. In contrast, foliar δ15N values and herbivore feces show a hump-shaped relationship with elevation, suggesting that plants are using a different N source, possibly of biotic origin. Thus at the extreme limits of plant life, biotic interactions may be just as important as abiotic processes, such as climate in explaining ecosystem δ15N values.

Nitrogen cycling in an extreme hyperarid environment inferred from δ15N analyses of plants, soils and herbivore diet

PubMed Central

Díaz, Francisca P.; Frugone, Matías; Gutiérrez, Rodrigo A.; Latorre, Claudio

2016-01-01

Climate controls on the nitrogen cycle are suggested by the negative correlation between precipitation and δ15N values across different ecosystems. For arid ecosystems this is unclear, as water limitation among other factors can confound this relationship. We measured herbivore feces, foliar and soil δ15N and δ13C values and chemically characterized soils (pH and elemental composition) along an elevational/climatic gradient in the Atacama Desert, northern Chile. Although very positive δ15N values span the entire gradient, soil δ15N values show a positive correlation with aridity as expected. In contrast, foliar δ15N values and herbivore feces show a hump-shaped relationship with elevation, suggesting that plants are using a different N source, possibly of biotic origin. Thus at the extreme limits of plant life, biotic interactions may be just as important as abiotic processes, such as climate in explaining ecosystem δ15N values. PMID:26956399

Scenario-targeted toxicity assessment through multiple endpoint bioassays in a soil posing unacceptable environmental risk according to regulatory screening values.

PubMed

Rodriguez-Ruiz, A; Etxebarria, J; Boatti, L; Marigómez, I

2015-09-01

Lanestosa is a chronically polluted site (derelict mine) where the soil (Lanestosa (LA) soil) exceeds screening values (SVs) of regulatory policies in force (Basque Country; Europe) for Zn, Pb and Cd. A scenario-targeted toxicity assessment was carried out on the basis of a multi-endpoint bioassay approach. Acute and chronic toxicity bioassays were conducted with selected test species (Vibrio fischeri, Dictyostelium discoideum, Lactuca sativa, Raphanus sativus and Eisenia fetida) in combination with chemical analysis of soils and elutriates and with bioaccumulation studies in earthworms. Besides, the toxicity profile was compared with that of the mine runoff (RO) soil and of a fresh artificially polluted soil (LAAPS) resembling LA soil pollutant profile. Extractability studies in LA soil revealed that Pb, Zn and Cd were highly available for exchange and/or release into the environment. Indeed, Pb and Zn were accumulated in earthworms and LA soil resulted to be toxic. Soil respiration, V. fischeri, vegetative and developmental cycles of D. discoideum and survival and juvenile production of E. fetida were severely affected. These results confirmed that LA soil had unacceptable environmental risk and demanded intervention. In contrast, although Pb and Zn concentrations in RO soil revealed also unacceptable risk, both metal extractability and toxicity were much lower than in LA soil. Thus, within the polluted site, the need for intervention varied between areas that posed dissimilar risk. Besides, since LAAPS, with a high exchangeable metal fraction, was the most toxic, ageing under in situ natural conditions seemingly contributed to attenuate LA soil risk. As a whole, combining multi-endpoint bioassays with scenario-targeted analysis (including leaching and ageing) provides reliable risk assessment in soils posing unacceptable environmental risk according to SVs, which is useful to optimise the required intervention measures.

Multisubstrate Isotope Labeling and Metagenomic Analysis of Active Soil Bacterial Communities

PubMed Central

Verastegui, Y.; Cheng, J.; Engel, K.; Kolczynski, D.; Mortimer, S.; Lavigne, J.; Montalibet, J.; Romantsov, T.; Hall, M.; McConkey, B. J.; Rose, D. R.; Tomashek, J. J.; Scott, B. R.

2014-01-01

ABSTRACT Soil microbial diversity represents the largest global reservoir of novel microorganisms and enzymes. In this study, we coupled functional metagenomics and DNA stable-isotope probing (DNA-SIP) using multiple plant-derived carbon substrates and diverse soils to characterize active soil bacterial communities and their glycoside hydrolase genes, which have value for industrial applications. We incubated samples from three disparate Canadian soils (tundra, temperate rainforest, and agricultural) with five native carbon (12C) or stable-isotope-labeled (13C) carbohydrates (glucose, cellobiose, xylose, arabinose, and cellulose). Indicator species analysis revealed high specificity and fidelity for many uncultured and unclassified bacterial taxa in the heavy DNA for all soils and substrates. Among characterized taxa, Actinomycetales (Salinibacterium), Rhizobiales (Devosia), Rhodospirillales (Telmatospirillum), and Caulobacterales (Phenylobacterium and Asticcacaulis) were bacterial indicator species for the heavy substrates and soils tested. Both Actinomycetales and Caulobacterales (Phenylobacterium) were associated with metabolism of cellulose, and Alphaproteobacteria were associated with the metabolism of arabinose; members of the order Rhizobiales were strongly associated with the metabolism of xylose. Annotated metagenomic data suggested diverse glycoside hydrolase gene representation within the pooled heavy DNA. By screening 2,876 cloned fragments derived from the 13C-labeled DNA isolated from soils incubated with cellulose, we demonstrate the power of combining DNA-SIP, multiple-displacement amplification (MDA), and functional metagenomics by efficiently isolating multiple clones with activity on carboxymethyl cellulose and fluorogenic proxy substrates for carbohydrate-active enzymes. PMID:25028422

Modeling preferential water flow and solute transport in unsaturated soil using the active region model

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

Sheng, F.; Wang, K.; Zhang, R.

2009-03-15

Preferential flow and solute transport are common processes in the unsaturated soil, in which distributions of soil water content and solute concentrations are often characterized as fractal patterns. An active region model (ARM) was recently proposed to describe the preferential flow and transport patterns. In this study, ARM governing equations were derived to model the preferential soil water flow and solute transport processes. To evaluate the ARM equations, dye infiltration experiments were conducted, in which distributions of soil water content and Cl{sup -} concentration were measured. Predicted results using the ARM and the mobile-immobile region model (MIM) were compared withmore » the measured distributions of soil water content and Cl{sup -} concentration. Although both the ARM and the MIM are two-region models, they are fundamental different in terms of treatments of the flow region. The models were evaluated based on the modeling efficiency (ME). The MIM provided relatively poor prediction results of the preferential flow and transport with negative ME values or positive ME values less than 0.4. On the contrary, predicted distributions of soil water content and Cl- concentration using the ARM agreed reasonably well with the experimental data with ME values higher than 0.8. The results indicated that the ARM successfully captured the macroscopic behavior of preferential flow and solute transport in the unsaturated soil.« less

Soil and geomorphological parameters to characterize natural environmental and human induced changes within the Guadarrama Range (Central Spain)

NASA Astrophysics Data System (ADS)

Schmid, Thomas; Inclán-Cuartas, Rosa M.; Santolaria-Canales, Edmundo; Saa, Antonio; Rodríguez-Rastrero, Manuel; Tanarro-Garcia, Luis M.; Luque, Esperanza; Pelayo, Marta; Ubeda, Jose; Tarquis, Ana; Diaz-Puente, Javier; De Marcos, Javier; Rodriguez-Alonso, Javier; Hernandez, Carlos; Palacios, David; Gallardo-Díaz, Juan; Fidel González-Rouco, J.

2016-04-01

Mediterranean mountain ecosystems are often complex and remarkably diverse and are seen as important sources of biological diversity. They play a key role in the water and sediment cycle for lowland regions as well as preventing and mitigating natural hazards especially those related to drought such as fire risk. However, these ecosystems are fragile and vulnerable to changes due to their particular and extreme climatic and biogeographic conditions. Some of the main pressures on mountain biodiversity are caused by changes in land use practices, infrastructure and urban development, unsustainable tourism, overexploitation of natural resources, fragmentation of habitats, particularly when located close to large population centers, as well as by pressures related toclimate change. The objective of this work is to select soil and geomorphological parameters in order to characterize natural environmental and human induced changes within the newly created National Park of the Sierra de Guadarrama in Central Spain, where the presence of the Madrid metropolitan area is the main factor of impact. This is carried out within the framework of the Guadarrama Monitoring Network (GuMNet) of the Campus de ExcelenciaInternacionalMoncloa, where long-term monitoring of the atmosphere, soil and bedrock are priority. This network has a total of ten stations located to the NW of Madrid and in this case, three stations have been selected to represent different ecosystems that include: 1) an alluvial plain in a lowland pasture area (La Herreria at 920 m a.s.l.), 2) mid mountain pine-forested and pasture area (Raso del Pino at 1801 m a.s.l.) and 3) high mountain grassland and rock area (Dos Hermanas at 2225 m a.s.l.). At each station a site geomorphological description, soil profile description and sampling was carried out. In the high mountain area information was obtained for monitoring frost heave activity and downslope soil movement. Basic soil laboratory analyses have been carried out

Development of soft extraction method for structural characterization of boreal forest soil proteins with MALDI-TOF/MS

NASA Astrophysics Data System (ADS)

Kanerva, Sanna; Ketola, Raimo A.; Kitunen, Veikko; Smolander, Aino; Kotiaho, Tapio

2010-05-01

Nitrogen (N) is usually the nutrient restricting productivity in boreal forests. Forest soils contain a great amount of nitrogen, but only a small part of it is in mineral form. Most part of soil N is bound in the structures of different organic compounds such as proteins, peptides, amino acids and more stabilized, refractory compounds. Due to the fact that soil organic N has a very important role in soil nutrient cycling and in plant nutrition, there is a need for more detailed knowledge of its chemistry in soil. Conventional methods to extract and analyze soil organic N are usually very destructive for structures of higher molecular weight organic compounds, such as proteins. The aim of this study was to characterize proteins extracted from boreal forest soil by "soft" extraction methods in order to maintain their molecular structure. The organic layer (F) from birch forest floor containing 78% of organic matter was sieved, freeze dried, pulverized, and extracted with a citrate or phosphate buffer (pH 6 or 8). Sequential extraction with the citrate or phosphate buffer and an SDS buffer (pH 6.8), slightly modified from the method of Chen et al. (2009, Proteomics 9: 4970-4973), was also done. Proteins were purified from the soil extract by extraction with buffered phenol and precipitated with methanol + 0.1M ammonium acetate at -20°C. Characterization of proteins was performed with matrix assisted laser desorption ionization - time-of-flight mass spectrometry (MALDI-TOF/MS) and the concentration of total proteins was measured using Bradford's method. Bovine serum albumin (BSA) was used as a positive control in the extractions and as a standard protein in Bradford's method. Our results showed that sequential extraction increased the amount of extracted proteins compared to the extractions without the SDS-buffer; however, it must be noted that the use of SDS-buffer very probably increased denaturization of proteins. Purification of proteins from crude soil extracts

Characterization of the N2O isotopic composition (15N, 18O and N2O isotopomers) emitted from incubated Amazon forest soils. Implications for the global N2O isotope budget

NASA Astrophysics Data System (ADS)

Pérez, T.; García, D.; Trumbore, S.; Tyler, S.; de Camargo, P.; Moreira, M.; Piccolo, M.; Park, S.; Boering, K.; Cerri, C.

2003-04-01

consumption of N2O as a potential method to determine the contributions of nitrification and denitrification. We measured the isotopomer composition of the incubated soils and calculated the site preference of each process for each soils. The site preference for nitrification and denitrification are: -114.5 and 56.6 per mil for clay Santarem soil, -75.2 and 11.8 per mil for sandy Santarem soil and -209.7 and 28.8 per mil for Nova Vida Farm soils, respectively. To our knowledge these are the first N2O isotopomer characterizations for nitrification and denitrification in soils. The results show that nitrifying bacteria population has 15N site preference fingerprints smaller by up to 200 per mil than denitrifying bacteria. This data set strongly suggests that N2O isotopomers can be used in concert with traditional N2O stable isotope measurements as constraints to differentiate microbial processes producing N2O. We can conclude that nitrifiers produce N2O with a smaller site preference values and more negative del 15N beta than do denitrifiers. These results show a new proxy to differentiate N2O formation processes in soil and will contribute to produce interpretations of the site preference isotopomeric N2O values found in the troposphere.

The History of Electromagnetic Induction Techniques in Soil Survey

NASA Astrophysics Data System (ADS)

Brevik, Eric C.; Doolittle, Jim

2014-05-01

Electromagnetic induction (EMI) has been used to characterize the spatial variability of soil properties since the late 1970s. Initially used to assess soil salinity, the use of EMI in soil studies has expanded to include: mapping soil types; characterizing soil water content and flow patterns; assessing variations in soil texture, compaction, organic matter content, and pH; and determining the depth to subsurface horizons, stratigraphic layers or bedrock, among other uses. In all cases the soil property being investigated must influence soil apparent electrical conductivity (ECa) either directly or indirectly for EMI techniques to be effective. An increasing number and diversity of EMI sensors have been developed in response to users' needs and the availability of allied technologies, which have greatly improved the functionality of these tools. EMI investigations provide several benefits for soil studies. The large amount of georeferenced data that can be rapidly and inexpensively collected with EMI provides more complete characterization of the spatial variations in soil properties than traditional sampling techniques. In addition, compared to traditional soil survey methods, EMI can more effectively characterize diffuse soil boundaries and identify included areas of dissimilar soils within mapped soil units, giving soil scientists greater confidence when collecting spatial soil information. EMI techniques do have limitations; results are site-specific and can vary depending on the complex interactions among multiple and variable soil properties. Despite this, EMI techniques are increasingly being used to investigate the spatial variability of soil properties at field and landscape scales.

Advanced solvent based methods for molecular characterization of soil organic matter by high-resolution mass spectrometry.

PubMed

Tfaily, Malak M; Chu, Rosalie K; Tolić, Nikola; Roscioli, Kristyn M; Anderton, Christopher R; Paša-Tolić, Ljiljana; Robinson, Errol W; Hess, Nancy J

2015-01-01

Soil organic matter (SOM), a complex, heterogeneous mixture of above and belowground plant litter and animal and microbial residues at various degrees of decomposition, is a key reservoir for carbon (C) and nutrient biogeochemical cycling in soil based ecosystems. A limited understanding of the molecular composition of SOM limits the ability to routinely decipher chemical processes within soil and accurately predict how terrestrial carbon fluxes will respond to changing climatic conditions and land use. To elucidate the molecular-level structure of SOM, we selectively extracted a broad range of intact SOM compounds by a combination of different organic solvents from soils with a wide range of C content. Our use of electrospray ionization (ESI) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) and a suite of solvents with varying polarity significantly expands the inventory of the types of organic molecules present in soils. Specifically, we found that hexane is selective for lipid-like compounds with very low O/C ratios (<0.1); water (H2O) was selective for carbohydrates with high O/C ratios; acetonitrile (ACN) preferentially extracts lignin, condensed structures, and tannin polyphenolic compounds with O/C > 0.5; methanol (MeOH) has higher selectivity toward compounds characterized with low O/C < 0.5; and hexane, MeOH, ACN, and H2O solvents increase the number and types of organic molecules extracted from soil for a broader range of chemically diverse soil types. Our study of SOM molecules by ESI FTICR MS revealed new insight into the molecular-level complexity of organics contained in soils. We present the first comparative study of the molecular composition of SOM from different ecosystems using ultra high-resolution mass spectrometry.

Preparation, Characterization, and UV Irradiation of Mars Soil Analogues Under Simulated Martian Conditions to Support Detection of Molecular Biomarkers

NASA Astrophysics Data System (ADS)

Fornaro, T.; Brucato, J. R.; ten Kate, I. L.; Siljeström, S.; Steele, A.; Cody, G. D.; Hazen, R. M.

2018-04-01

We present laboratory activities of preparation, characterization, and UV irradiation processing of Mars soil analogues, which are key to support both in situ exploration and sample return missions devoted to detection of molecular biomarkers on Mars.

Converting Soil Moisture Observations to Effective Values for Improved Validation of Remotely Sensed Soil Moisture

NASA Technical Reports Server (NTRS)

Laymon, Charles A.; Crosson, William L.; Limaye, Ashutosh; Manu, Andrew; Archer, Frank

2005-01-01

We compare soil moisture retrieved with an inverse algorithm with observations of mean moisture in the 0-6 cm soil layer. A significant discrepancy is noted between the retrieved and observed moisture. Using emitting depth functions as weighting functions to convert the observed mean moisture to observed effective moisture removes nearly one-half of the discrepancy noted. This result has important implications in remote sensing validation studies.

Comparison of ion-exchange resin counterions in the nutrient measurement of calcareous soils: implications for correlative studies of plant-soil relationships

USGS Publications Warehouse

Sherrod, S.K.; Belnap, Jayne; Miller, M.E.

2003-01-01

For more than 40 years, ion-exchange resins have been used to characterize nutrient bioavailability in terrestrial and aquatic ecosystems. To date, however, no standardized methodology has been developed, particularly with respect to the counterions that initially occupy resin exchange sites. To determine whether different resin counterions yield different measures of soil nutrients and rank soils differently with respect to their measured nutrient bioavailability, we compared nutrient measurements by three common counterion combinations (HCl, HOH, and NaHCO3). Five sandy calcareous soils were chosen to represent a range of soil characteristics at Canyonlands National Park, Utah, and resin capsules charged with the different counterions equilibrated in saturated pastes of these soils for one week. Data were converted to proportions of total ions of corresponding charge for ANOVA. Results from the different methods were not comparable with respect to any nutrient. Of eleven nutrients measured, all but iron (Fe2+), manganese (Mn2+), and zinc (Zn2+) differed significantly (pa??0.05) as a function of soilcounterion interactions; Fe2+ and Zn2+ varied as functions of counterion alone. Of the counterion combinations, HCl-resins yielded the most net ion exchange with all measured nutrients except Na+, and the three of which desorbed in the greatest quantities from HOH-resins. Conventional chemical extractions using ammonium acetate generally yielded high proportional values of Ca2+, K+, and Na+. Further, among-soil rankings of nutrient bioavailability varied widely among methods. This study highlights the fact that various ion-exchange resin techniques for measuring soil nutrients may have differential effects on the soil-resin environment and yield data that should not be compared nor considered interchangeable. The most appropriate methods for characterizing soil-nutrient bioavailability depends on soil characteristics and likely on the physiological uptake mechanisms of

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

PubMed

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

2010-07-01

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

Characterization of tillage effects on soil permeability using different measures of macroporosity derived from tension infiltrometry

NASA Astrophysics Data System (ADS)

Bodner, G.; Schwen, A.; Scholl, P.; Kammerer, G.; Buchan, G.; Kaul, H.-P.; Loiskandl, W.

2010-05-01

approaches (direct vs. inverse evaluation, capillary vs. flow weighted pore radius). We will show the influence of the distinct evaluation procedures on the resulting effective macroporosity, as well as on the relationships between macropore radius and hydraulic conductivity (Moret and Arrúe, 2007) and pore fraction respectively (Carey et al., 2007). The infiltration measurements used in this study were obtained in a long-term tillage trial located in the semi-arid region of Eastern Austria. Measurements were taken five times over the vegetation period, starting immediately after tillage until harvest of the winter wheat crop. Three tillage systems were evaluated, being conventional tillage with plough, minimum tillage with chisel and no-tillage. Additional to infiltration measurements, also soil water content was monitored continuously by a capacitance probe in all three replicates of each tillage treatment in 10, 20 and 40 cm soil depth. Water content time series are used to derive flow velocity in the wet range by cross-correlation analysis (Wu et al., 1997). This effective parameter of water transmission will then be compared to the flow behaviour expected from the characterization of soil macroporosity. We will show that mainly in no-tillage systems large macropores contribute essentially to flow and therefore the decision on pore measure and evaluation procedure to be used leads to substantial differences. For a detailed comparison of tillage effects on soil hydraulic properties it is therefore essential to analyse the contribution of different tension infiltrometry based evaluation methods to explain effective water transmission through the complex porous network of the soil. References Carey, S.K., Quinton, W.L., Goeller, N.T. 2007. Field and laboratory estimates of pore size properties and hydraulic characteristics for subarctic organic soils. Hydrol. Process. 21, 2560-2571. Moret, D., Arrúe, J.L. 2007. Characterizing soil water conducting macro- and mesoporosity

Characterization of carotenoids in soil bacteria and investigation of their photodegradation by UVA radiation via resonance Raman spectroscopy.

PubMed

Kumar B N, Vinay; Kampe, Bernd; Rösch, Petra; Popp, Jürgen

2015-07-07

A soil habitat consists of an enormous number of pigmented bacteria with the pigments mainly composed of diverse carotenoids. Most of the pigmented bacteria in the top layer of the soil are photoprotected from exposure to huge amounts of UVA radiation on a daily basis by these carotenoids. The photostability of these carotenoids depends heavily on the presence of specific features like a carbonyl group or an ionone ring system on its overall structure. Resonance Raman spectroscopy is one of the most sensitive and powerful techniques to detect and characterize these carotenoids and also monitor processes associated with them in their native system at a single cell resolution. However, most of the resonance Raman profiles of carotenoids have very minute differences, thereby making it extremely difficult to confirm if these differences are attributed to the presence of different carotenoids or if it is a consequence of their interaction with other cellular components. In this study, we devised a method to overcome this problem by monitoring also the photodegradation of the carotenoids in question by UVA radiation wherein a differential photodegradation response will confirm the presence of different carotenoids irrespective of the proximities in their resonance Raman profiles. Using this method, the detection and characterization of carotenoids in pure cultures of five species of pigmented coccoid soil bacteria is achieved. We also shed light on the influence of the structure of the carotenoid on its photodegradation which can be exploited for use in the characterization of carotenoids via resonance Raman spectroscopy.

Characterization and evolution of dissolved organic matter in acidic forest soil and its impact on the mobility of major and trace elements (case of the Strengbach watershed)

NASA Astrophysics Data System (ADS)

Gangloff, Sophie; Stille, Peter; Pierret, Marie-Claire; Weber, Tiphaine; Chabaux, François

2014-04-01

Dissolved Organic Carbon (DOC) plays an important role in the behavior of major and trace elements in the soil and influences their transfer from soil to soil solution. The first objective of this study is to characterize different organic functional groups for the Water Extractable Organic Carbon (WEOC) fractions of a forest soil as well as their evolution with depth. The second objective is to clarify the influence of these organic functional groups on the migration of the trace elements in WEOC fractions compared to those in the soil solution obtained by lysimeter plates. All experiments have been performed on an acidic forest soil profile (five depths in the first meter) of the experimental spruce parcel in the Stengbach catchment. The Infra-red spectra of the freeze-dried WEOC fractions show a modification of the molecular structure with depth, i.e. a decrease of the polar compounds such as polysaccharides and an increase of the less polar hydro-carbon functional groups with a maximum value of the aromaticity at 30 cm depth. A Hierarchical Ascending Classification (HAC) of the evolution of Water Extractable Chemical Elements (WECE) with the evolution of the organic functional groups in the organic matter (OM) enriched soil compartments permits recognition of relationships between trace element behavior and the organic functional group variations. More specifically, Pb is preferentially bound to the carboxylic acid function of DOC mainly present in the upper soil compartment and rare earth elements (REE) show similar behavior to Fe, V and Cr with a good affinity to carboxy-phenolic and phenolic groups of DOC. The experimental results show that heavy REE compared to light REE are preferentially bound to the aromatic functional group. This different behavior fractionates the REE pattern of soil solutions at 30 cm depth due to the here observed aromaticity enrichment of DOC. These different affinities for the organic functional groups of the DOC explain some

Soil CO₂ dynamics in a tree island soil of the Pantanal: the role of soil water potential.

PubMed

Johnson, Mark S; Couto, Eduardo Guimarães; Pinto, Osvaldo B; Milesi, Juliana; Santos Amorim, Ricardo S; Messias, Indira A M; Biudes, Marcelo Sacardi

2013-01-01

The Pantanal is a biodiversity hotspot comprised of a mosaic of landforms that differ in vegetative assemblages and flooding dynamics. Tree islands provide refuge for terrestrial fauna during the flooding period and are particularly important to the regional ecosystem structure. Little soil CO₂ research has been conducted in this region. We evaluated soil CO₂ dynamics in relation to primary controlling environmental parameters (soil temperature and soil water). Soil respiration was computed using the gradient method using in situ infrared gas analyzers to directly measure CO₂ concentration within the soil profile. Due to the cost of the sensors and associated equipment, this study was unreplicated. Rather, we focus on the temporal relationships between soil CO₂ efflux and related environmental parameters. Soil CO₂ efflux during the study averaged 3.53 µmol CO₂ m⁻² s⁻¹, and was equivalent to an annual soil respiration of 1220 g C m⁻² y⁻¹. This efflux value, integrated over a year, is comparable to soil C stocks for 0-20 cm. Soil water potential was the measured parameter most strongly associated with soil CO₂ concentrations, with high CO₂ values observed only once soil water potential at the 10 cm depth approached zero. This relationship was exhibited across a spectrum of timescales and was found to be significant at a daily timescale across all seasons using conditional nonparametric spectral Granger causality analysis. Hydrology plays a significant role in controlling CO₂ efflux from the tree island soil, with soil CO₂ dynamics differing by wetting mechanism. During the wet-up period, direct precipitation infiltrates soil from above and results in pulses of CO₂ efflux from soil. The annual flood arrives later, and saturates soil from below. While CO₂ concentrations in soil grew very high under both wetting mechanisms, the change in soil CO₂ efflux was only significant when soils were wet from above.

Characterization of atrazine binding to dissolved organic matter of soil under different types of land use.

PubMed

Zhu, Long-Ji; Zhao, Yue; Chen, Yan-Ni; Cui, Hong-Yang; Wei, Yu-Quan; Liu, Hai-Long; Chen, Xiao-Meng; Wei, Zi-Min

2018-01-01

Atrazine is widely used in agriculture. In this study, dissolved organic matter (DOM) from soils under four types of land use (forest (F), meadow (M), cropland (C) and wetland (W)) was used to investigate the binding characteristics of atrazine. Fluorescence excitation-emission matrix-parallel factor (EEM-PARAFAC) analysis, two-dimensional correlation spectroscopy (2D-COS) and Stern-Volmer model were combined to explore the complexation between DOM and atrazine. The EEM-PARAFAC indicated that DOM from different sources had different structures, and humic-like components had more obvious quenching effects than protein-like components. The Stern-Volmer model combined with correlation analysis showed that log K values of PARAFAC components had a significant correlation with the humification of DOM, especially for C3 component, and they were all in the same order as follows: meadow soil (5.68)>wetland soil (5.44)>cropland soil (5.35)>forest soil (5.04). The 2D-COS further confirmed that humic-like components firstly combined with atrazine followed by protein-like components. These findings suggest that DOM components can significantly influence the bioavailability, mobility and migration of atrazine in different land uses. Copyright © 2016 Elsevier Inc. All rights reserved.

Uncertainty in Pedotransfer Functions from Soil Survey Data

NASA Astrophysics Data System (ADS)

Pachepsky, Y. A.; Rawls, W. J.

2002-05-01

Pedotransfer functions (PTFs) are empirical relationships between hard-to-get soil parameters, i.e. hydraulic properties, and more easily obtainable basic soil properties, such as texture. Use of PTFs in large-scale projects and pilot studies relies on data of soil survey that provides soil basic data as a categorical information. Unlike numerical variables, categorical data cannot be directly used in statistical regressions or neural networks to develop PTFs. Objectives of this work were (a) to find and test techniques to develop PTFs for soil water retention and saturated hydraulic conductivity with soil categorical data as inputs, (b) to evaluate sources of uncertainty in results of such PTFs and to research opportunities of mitigating the uncertainty. We used a subset of about 12,000 samples from the US National Soil characterization database to estimate water retention, and the data set for circa 1000 hydraulic conductivity measurements done in the US. Regression trees and polynomial neural networks based on dummy coding were the techniques tried for the PTF development. The jackknife validation was used to prevent the over-parameterization. Both techniques were equally efficient in developing PTFs, but regression trees gave much more transparent results. Textural class was the leading predictor with RMSE values of about 6.5 and 4.1 vol.% for water retention at -33 and -1500 kPa, respectively. The RMSE values decreased 10% when the laboratory textural analysis was used to establish the textural class. Textural class in the field was determined correctly only in 41% of all cases. To mitigate this source of error, we added slopes, position on the slope classes, and land surface shape classes to the list of PTF inputs. Regression trees generated topotextural groups that encompassed several textural classes. Using topographic variables and soil horizon appeared to be the way to make up for errors made in field determination of texture. Adding field descriptors of

Characterizing permafrost soil active layer dynamics and sensitivity to landscape spatial heterogeneity in Alaska

DOE PAGES

Yi, Yonghong; Kimball, John S.; Chen, Richard; ...

2017-05-30

An important feature of the Arctic is large spatial heterogeneity in active layer conditions, which is generally poorly represented by global models. In this study, we developed a spatially integrated modelling and analysis framework combining field observations, local scale (~ 50 m) active layer thickness (ALT) and soil moisture maps derived from airborne low frequency (L + P-band) radar measurements, and global satellite environmental observations to investigate the ALT sensitivity to recent climate trends and landscape heterogeneity in Alaska. Model simulated ALT results show good correspondence with in-situ measurements in higher permafrost probability (PP ≥ 70 %) areas (n =more » 33, R = 0.60, mean bias = 1.58 cm, RMSE = 20.32 cm). The model results also reveal widespread ALT deepening since 2001, with smaller ALT increases in northern Alaska (mean trend = 0.32 ± 1.18 cm yr -1) and much larger increases (> 3 cm yr -1) across interior and southern Alaska. The positive ALT trend coincides with regional warming and a longer snow-free season (R = 0.60 ± 0.32). Uncertainty in the spatial and vertical distribution of soil organic carbon (SOC) was found to be the most important factor affecting model ALT accuracy. Here, potential improvements in characterizing SOC heterogeneity, including better spatial sampling of soil conditions and advances in remote sensing of SOC and soil moisture, will enable more accurate predictions of permafrost active layer conditions.« less

Characterizing permafrost soil active layer dynamics and sensitivity to landscape spatial heterogeneity in Alaska

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

Yi, Yonghong; Kimball, John S.; Chen, Richard

An important feature of the Arctic is large spatial heterogeneity in active layer conditions, which is generally poorly represented by global models. In this study, we developed a spatially integrated modelling and analysis framework combining field observations, local scale (~ 50 m) active layer thickness (ALT) and soil moisture maps derived from airborne low frequency (L + P-band) radar measurements, and global satellite environmental observations to investigate the ALT sensitivity to recent climate trends and landscape heterogeneity in Alaska. Model simulated ALT results show good correspondence with in-situ measurements in higher permafrost probability (PP ≥ 70 %) areas (n =more » 33, R = 0.60, mean bias = 1.58 cm, RMSE = 20.32 cm). The model results also reveal widespread ALT deepening since 2001, with smaller ALT increases in northern Alaska (mean trend = 0.32 ± 1.18 cm yr -1) and much larger increases (> 3 cm yr -1) across interior and southern Alaska. The positive ALT trend coincides with regional warming and a longer snow-free season (R = 0.60 ± 0.32). Uncertainty in the spatial and vertical distribution of soil organic carbon (SOC) was found to be the most important factor affecting model ALT accuracy. Here, potential improvements in characterizing SOC heterogeneity, including better spatial sampling of soil conditions and advances in remote sensing of SOC and soil moisture, will enable more accurate predictions of permafrost active layer conditions.« less

Caresoil: A multidisciplinar Project to characterize, remediate, monitor and evaluate the risk of contaminated soils in Madrid (Spain)

NASA Astrophysics Data System (ADS)

Muñoz-Martín, Alfonso; Antón, Loreto; Granja, Jose Luis; Villarroya, Fermín; Montero, Esperanza; Rodríguez, Vanesa

2016-04-01

Soil contamination can come from diffuse sources (air deposition, agriculture, etc.) or local sources, these last being related to anthropogenic activities that are potentially soil contaminating activities. According to data from the EU, in Spain, and particularly for the Autonomous Community of Madrid, it can be considered that heavy metals, toxic organic compounds (including Non Aqueous Phases Liquids, NAPLs) and combinations of both are the main problem of point sources of soil contamination in our community. The five aspects that will be applied in Caresoil Program (S2013/MAE-2739) in the analysis and remediation of a local soil contamination are: 1) the location of the source of contamination and characterization of soil and aquifer concerned, 2) evaluation of the dispersion of the plume, 3) application of effective remediation techniques, 4) monitoring the evolution of the contaminated soil and 5) risk analysis throughout this process. These aspects involve advanced technologies (hydrogeology, geophysics, geochemistry,...) that require new developing of knowledge, being necessary the contribution of several researching groups specialized in the fields previously cited, as they are those integrating CARESOIL Program. Actually two cases concerning hydrocarbon spills, as representative examples of soil local contamination in Madrid area, are being studied. The first is being remediated and we are monitoring this process to evaluate its effectiveness. In the second location we are defining the extent of contamination in soil and aquifer to define the most effective remediation technique.

Soil cover characterization at large scale: the example of Perugia Province in central Italy

NASA Astrophysics Data System (ADS)

Fanelli, Giulia; Salciarini, Diana; Tamagnini, Claudio

2015-04-01

In the last years, physically-based models aimed at predicting the occurrence of landslides have had a large diffusion because the opportunity of having landslide susceptibility maps can be essential to reduce damages and human losses. On one hand physically-based models rationally analyse problems, because mathematically describe the physical processes that actually happen, on the other hand their diffusion is limited by the difficulty of having and managing accurate data over large areas. For this reason, and also because in the Perugia province geotechnical data are partial and not regularly distributed, a data collection campaign has been started in order to have a wide physical-mechanical data set that can be used to apply any physically-based model. The collected data have been derived from mechanical tests and investigations performed to characterize the soil. The data set includes about 3000 points and each record is characterized by the following quantitative information: coordinates, geological description, cohesion, friction angle. Besides, the records contain the results of seismic tests that allow knowing the shear waves velocity in the first 30 meters of soil. The database covers the whole Perugia province territory and it can be used to evaluate the effects of both rainfall-induced and earthquake-induced landslides. The database has been analysed in order to exclude possible outliers; starting from the all data set, 16 lithological units have been isolated, each one with homogeneous geological features and the same mechanical behaviour. It is important to investigate the quality of the data and know how much they are reliable; therefore statistical analyses have been performed to quantify the dispersion of the data - i.e. relative and cumulative frequency - and also geostatistical analyses to know the spatial correlation - i.e. the variogram. The empirical variogram is a common and useful tool in geostatistics because it quantifies the spatial

Maximizing the value of pressure data in saline aquifer characterization

NASA Astrophysics Data System (ADS)

Yoon, Seonkyoo; Williams, John R.; Juanes, Ruben; Kang, Peter K.

2017-11-01

The injection and storage of freshwater in saline aquifers for the purpose of managed aquifer recharge is an important technology that can help ensure sustainable water resources. As a result of the density difference between the injected freshwater and ambient saline groundwater, the pressure field is coupled to the spatial salinity distribution, and therefore experiences transient changes. The effect of variable density can be quantified by the mixed convection ratio, which is a ratio between the strength of two convection processes: free convection due to the density differences and forced convection due to hydraulic gradients. We combine a density-dependent flow and transport simulator with an ensemble Kalman filter (EnKF) to analyze the effects of freshwater injection rates on the value-of-information of transient pressure data for saline aquifer characterization. The EnKF is applied to sequentially estimate heterogeneous aquifer permeability fields using real-time pressure data. The performance of the permeability estimation is analyzed in terms of the accuracy and the uncertainty of the estimated permeability fields as well as the predictability of breakthrough curve arrival times in a realistic push-pull setting. This study demonstrates that injecting fluids at a rate that balances the two characteristic convections can maximize the value of pressure data for saline aquifer characterization.

Magnetic Susceptibility Measurements for in Situ Characterization of Lunar Soil

NASA Technical Reports Server (NTRS)

Oder, R. R.

1992-01-01

Magnetic separation is a viable method for concentration of components of lunar soils and rocks for use as feedstocks for manufacture of metals, oxygen, and for recovery of volatiles such as He-3. Work with lunar materials indicates that immature soils are the best candidates for magnetic beneficiation. The magnetic susceptibility at which selected soil components such as anorthite, ilmenite, or metallic iron are separated is not affected by soil maturity, but the recovery of the concentrated components is. Increasing soil maturity lowers recovery. Mature soils contain significant amounts of glass-encased metallic iron. Magnetic susceptibility, which is sensitive to metallic iron content, can be used to measure soil maturity. The relationship between the ratio of magnetic susceptibility and iron oxide and the conventional maturity parameter, I(sub s)/FeO, ferromagnetic resonant intensity divided by iron oxide content is given. The magnetic susceptibilities were determined using apparatus designed for magnetic separation of the lunar soils.

Characterization of interactions between soil solid phase and soil solution in the initial ecosystem development phase

NASA Astrophysics Data System (ADS)

Zimmermann, Claudia; Schaaf, Wolfgang

2010-05-01

analyzed in two weeks intervals for C and N contents (including δ13C), pH and ion concentrations. The results show that the initial phase of the experiment is characterized by intensive leaching of C and N from the litter and transformation as well as leaching from the substrate. Calcium leaching is caused mainly by carbonate dissolution from the substrates. In contrast, magnesium and especially potassium are leached in initially high amounts from the litter, but are strongly retained in the soil. The addition of litter promotes microbial CO2 production as shown by a strong increase of respiration due to easily available organic substances at the beginning of the experiment. Litter of L. corniculatus induced also a high initial peak in N2O emission as well as higher nitrification and NO3-N leaching. Leaching of DOC and TDN was clearly affected by the substrate texture, illustrated by intensive DOC leaching from the sand at the beginning of the experiment but shifting later to higher leaching rates from the loamy sand. References: Gerwin W, Schaaf W, Biemelt D, Fischer A, Winter S, Hüttl RF (2009) The artificial catchment 'Chicken Creek' (Lusatia, Germany) - a landscape laboratory for interdisciplinary studies of initial ecosystem development. Ecolological Engineering 35, 1786-1796.

Soil property effects on wind erosion of organic soils

NASA Astrophysics Data System (ADS)

Zobeck, Ted M.; Baddock, Matthew; Scott Van Pelt, R.; Tatarko, John; Acosta-Martinez, Veronica

2013-09-01

stability. The effect of soil properties on sediment flux varied among flux types. Saltation flux was adequately predicted with simple linear regression models. Dry mechanical stability was the best single soil property linearly related to saltation flux. Simple linear models with soil properties as independent variables were not well correlated with PM10E values (mass flux). A second order polynomial equation with OM as the independent variable was found to be most highly correlated with PM10E values. These results demonstrate that variations in sediment and dust emissions can be linked to soil properties using simple models based on one or more soil properties to estimate saltation mass flux and PM10E values from organic and organic-rich soils.

The dissolved organic matter as a potential soil quality indicator in arable soils of Hungary.

PubMed

Filep, Tibor; Draskovits, Eszter; Szabó, József; Koós, Sándor; László, Péter; Szalai, Zoltán

2015-07-01

Although several authors have suggested that the labile fraction of soils could be a potential soil quality indicator, the possibilities and limitations of using the dissolved organic matter (DOM) fraction for this purpose have not yet been investigated. The objective of this study was to evaluate the hypothesis that DOM is an adequate indicator of soil quality. To test this, the soil quality indices (SQI) of 190 arable soils from a Hungarian dataset were estimated, and these values were compared to DOM parameters (DOC and SUVA254). A clear difference in soil quality was found between the soil types, with low soil quality for arenosols (average SQI 0.5) and significantly higher values for gleysols, vertisols, regosols, solonetzes and chernozems. The SQI-DOC relationship could be described by non-linear regression, while a linear connection was observed between SQI and SUVA. The regression equations obtained for the dataset showed only one relatively weak significant correlation between the variables, for DOC (R (2) = 0.157(***); n = 190), while non-significant relationships were found for the DOC and SUVA254 values. However, an envelope curve operated with the datasets showed the robust potential of DOC to indicate soil quality changes, with a high R (2) value for the envelope curve regression equation. The limitations to using the DOM fraction of soils as a quality indicator are due to the contradictory processes which take place in soils in many cases.

Characterization of biocontrol bacterial strains isolated from a suppressiveness-induced soil after amendment with composted almond shells.

PubMed

Vida, Carmen; Cazorla, Francisco M; de Vicente, Antonio

The improvement in soil quality of avocado crops through organic amendments with composted almond shells has a positive effect on crop yield and plant health, and enhances soil suppressiveness against the phytopathogenic fungus Rosellinia necatrix. In previous studies, induced soil suppressiveness against this pathogen was related to stimulation of Gammaproteobacteria, especially some members of Pseudomonas spp. with biocontrol-related activities. In this work, we isolated bacteria from this suppressiveness-induced amended soil using a selective medium for Pseudomonas-like microorganisms. We characterized the obtained bacterial collection to aid in identification, including metabolic profiles, antagonistic responses, hybridization to biosynthetic genes of antifungal compounds, production of lytic exoenzymatic activities and plant growth-promotion-related traits, and sequenced and compared amplified 16S rDNA genes from representative bacteria. The final selection of representative strains mainly belonged to the genus Pseudomonas, but also included the genera Serratia and Stenotrophomonas. Their biocontrol-related activities were assayed using the experimental avocado model, and results showed that all selected strains protected the avocado roots against R. necatrix. This work confirmed the biocontrol activity of these Gammaproteobacteria-related members against R. necatrix following specific stimulation in a suppressiveness-induced soil after a composted almond shell application. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Measurement of δ13C values of soil amino acids by GC-C-IRMS using trimethylsilylation: a critical assessment.

PubMed

Rubino, Mauro; Milin, Sylvie; D'Onofrio, Antonio; Signoret, Patrick; Hatté, Christine; Balesdent, Jérôme

2014-01-01

In this study, we evaluated trimethylsilyl (TMS) derivatives as derivatization reagents for the compound-specific stable carbon isotope analysis of soil amino acids by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). We used non-proteinogenic amino acids to show that the extraction-derivatization-analysis procedure provides a reliable method to measure δ(13)C values of amino acids extracted from soil. However, we found a number of drawbacks that significantly increase the final total uncertainty. These include the following: production of multiple peaks for each amino acid, identified as di-, tri- and tetra-TMS derivatives; a number of TMS-carbon (TMS-C) atoms added lower than the stoichiometric one, possibly due to incomplete combustion; different TMS-C δ(13)C for di-, tri- and tetra-TMS derivatives. For soil samples, only four amino acids (leucine, valine, threonine and serine) provide reliable δ(13)C values with a total average uncertainty of 1.3 ‰. We conclude that trimethylsilyl derivatives are only suitable for determining the (13)C incorporation in amino acids within experiments using (13)C-labelled tracers but cannot be applied for amino acids with natural carbon isotope abundance until the drawbacks described here are overcome and the measured total uncertainty significantly decreased.

Fertirrigation with sugarcane vinasse: Foreseeing potential impacts on soil and water resources through vinasse characterization.

PubMed

Fuess, Lucas T; Rodrigues, Isabella J; Garcia, Marcelo L

2017-09-19

This paper reports the characterization of the polluting potential of sugarcane vinasse, the main wastewater from ethanol production. Compositional data from vinasse samples collected from sugarcane biorefineries were used to predict negative effects on the soil, water resources and crops potentially associated with fertirrigation, the primary final destination of vinasse in Brazil. High risks of soil salinization were associated with the land disposal of vinasse, as evidenced by the high levels of total dissolved solids (TDS; >4,000 mg L -1 ) and electrical conductivity (>6.7 dS m -1 ). The high TDS levels coupled with the high biodegradable organic content of vinasse (>14 g L -1 ) also favor organic overloading events, leading to local anaerobiosis conditions. Conversely, soil sodification should not be observed in areas fertirrigated with sugarcane vinasse, given the low Na concentrations (<66 mg L -1 ) relative to Mg (>145.1 mg L -1 ) and Ca (>458.4 mg L -1 ) levels. Priority pollutants (Cu, Cr, Ni, Pb and Zn) and phytotoxic elements (Al and Fe) were also found in the analyzed samples; however, relevant environmental impacts should not be associated with these particular constituents. Overall, the relatively simple methodology used herein could efficiently replace massive field data collection to provide a basic understanding of the fate of vinasse in the environment in order to highlight the priority points to be considered in the management of this effluent. In summary, the prompt implementation of treatment plants in distilleries, in addition to a continuous and broad compositional characterization of vinasse, is essential to guarantee its adequate reuse.

Soil types and forest canopy structures in southern Missouri: A first look with AIS data

NASA Technical Reports Server (NTRS)

Green, G. M.; Arvidson, R. E.

1986-01-01

Spectral reflectance properties of deciduous oak-hickory forests covering the eastern half of the Rolla Quadrangle were examined using Thematic Mapper (TM) data acquired in August and December, 1982 and Airborne Imaging Spectrometer (AIS) data acquired in August, 1985. For the TM data distinctly high relative reflectance values (greater than 0.3) in the near infrared (Band 4, 0.73 to 0.94 micrometers) correspond to regions characterized by xeric (dry) forests that overlie soils with low water retention capacities. These soils are derived primarily from rhyolites. More mesic forests characterized by lower TM band 4 relative reflectances are associated with soils of higher retention capacities derived predominately from non-cherty carbonates. The major factors affecting canopy reflectance appear to be the leaf area index (LAI) and leaf optical properties. The Suits canopy reflectance model predicts the relative reflectance values for the xeric canopies. The mesic canopy reflectance is less well matched and incorporation of canopy shadowing caused by the irregular nature of the mesic canopy may be necessary. Preliminary examination of high spectral resolution AIS data acquired in August of 1985 reveals no more information than found in the broad band TM data.

Assessing soil erosion risk using RUSLE through a GIS open source desktop and web application.

PubMed

Duarte, L; Teodoro, A C; Gonçalves, J A; Soares, D; Cunha, M

2016-06-01

Soil erosion is a serious environmental problem. An estimation of the expected soil loss by water-caused erosion can be calculated considering the Revised Universal Soil Loss Equation (RUSLE). Geographical Information Systems (GIS) provide different tools to create categorical maps of soil erosion risk which help to study the risk assessment of soil loss. The objective of this study was to develop a GIS open source application (in QGIS), using the RUSLE methodology for estimating erosion rate at the watershed scale (desktop application) and provide the same application via web access (web application). The applications developed allow one to generate all the maps necessary to evaluate the soil erosion risk. Several libraries and algorithms from SEXTANTE were used to develop these applications. These applications were tested in Montalegre municipality (Portugal). The maps involved in RUSLE method-soil erosivity factor, soil erodibility factor, topographic factor, cover management factor, and support practices-were created. The estimated mean value of the soil loss obtained was 220 ton km(-2) year(-1) ranged from 0.27 to 1283 ton km(-2) year(-1). The results indicated that most of the study area (80 %) is characterized by very low soil erosion level (<321 ton km(-2) year(-1)) and in 4 % of the studied area the soil erosion was higher than 962 ton km(-2) year(-1). It was also concluded that areas with high slope values and bare soil are related with high level of erosion and the higher the P and C values, the higher the soil erosion percentage. The RUSLE web and the desktop application are freely available.

REGIONAL SOIL WATER RETENTION IN THE CONTIGUOUS US: SOURCES OF VARIABILITY AND VOLCANIC SOIL EFFECTS

EPA Science Inventory

Water retention of mineral soil is often well predicted using algorithms (pedotransfer functions) with basic soil properties but the spatial variability of these properties has not been well characterized. A further source of uncertainty is that water retention by volcanic soils...

Designation of less favorable areas by the regionalization of soil degradation on various spatial scales

NASA Astrophysics Data System (ADS)

Pásztor, L.; Szabó, J.; Bakacsi, Zs.; Laborczi, A.

2009-04-01

One of the main objectives of the EU's Common Agricultural Policy is to encourage maintaining agricultural production in less favorable areas (LFA) in order (among others) to sustain agricultural production and use natural resources, in such a way to secure both stable production and income to farmers and to protect the environment. LFA assignment has both ecological and severe economical aspects. Delimitation of LFAs can be carried out by using biophysical diagnostic criteria on low soil productivity and poor climate conditions. Identification of low-productivity areas requires regionalization of soil functions related to food and other biomass production. This process can be carried out in different scales from national to local level, but always requires map-based pedological and further environmental information with appropriate spatial resolution. For the regionalization of less productive areas in national scale a functional approach was used which integrates the knowledge on soil degradation processes in nationwide level. Specific soil threats were classified into ranked categories. Supposing (quasi)uniform distribution of vulnerability measure along these classes, we introduced a "standardized" value as a ratio of the class order to the maximum class order expressed in percentage. For the overall spatial characterization of degradation status, spatial information was integrated in a result map by summarizing the degradation specific "standardized" cell values. This map in one hand has been used for the delineation of soil degradation regions. On the other hand appropriate spatial aggregation of index values on geographical and administrative regions is suitable for their quantitative comparison thus they can be ranked and this feature can be used for the identification of less favorable areas. At the more detailed, county level the Digital Kreybig Soil Information System was used as a tool of the regionalization of soil functions related to soil

Strategies to improve reference databases for soil microbiomes

DOE PAGES

Choi, Jinlyung; Yang, Fan; Stepanauskas, Ramunas; ...

2016-12-09

A database of curated genomes is needed to better assess soil microbial communities and their processes associated with differing land management and environmental impacts. Interpreting soil metagenomic datasets with existing sequence databases is challenging because these datasets are biased towards medical and biotechnology research and can result in misleading annotations. We have curated a database of 928 genomes of soil-associated organisms (888 bacteria, 34 archaea, and 6 fungi). Using this database as a representation of the current state of knowledge of soil microbes that are well-characterized, we evaluated its composition and compared it to broader microbial databases, specifically NCBI’s RefSeq,more » as well as 3,035 publicly available soil amplicon datasets. These comparisons identified phyla and functions that are enriched in soils as well as those that may be underrepresented in RefSoil. For example, RefSoil was observed to have increased representation of Firmicutes despite its low abundance in soil environments and also lacked representation of Acidobacteria and Verrucomicrobia, which are abundant in soils. Our comparison of RefSoil to soil amplicon datasets allowed us to identify targets that if cultured or sequenced would significantly increase the biodiversity represented within RefSoil. To demonstrate the opportunities to access these underrepresented targets, we employed single cell genomics in a pilot experiment to recover 14 genomes from the "most wanted" list, which improved RefSoil's representation of EMP sequences by 7% by abundance. This effort demonstrates the value of RefSoil in the guidance of future research efforts and the capability of single cell genomics as a practical means to fill the existing genomic data gaps.« less

Strategies to improve reference databases for soil microbiomes

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

Choi, Jinlyung; Yang, Fan; Stepanauskas, Ramunas

A database of curated genomes is needed to better assess soil microbial communities and their processes associated with differing land management and environmental impacts. Interpreting soil metagenomic datasets with existing sequence databases is challenging because these datasets are biased towards medical and biotechnology research and can result in misleading annotations. We have curated a database of 928 genomes of soil-associated organisms (888 bacteria, 34 archaea, and 6 fungi). Using this database as a representation of the current state of knowledge of soil microbes that are well-characterized, we evaluated its composition and compared it to broader microbial databases, specifically NCBI’s RefSeq,more » as well as 3,035 publicly available soil amplicon datasets. These comparisons identified phyla and functions that are enriched in soils as well as those that may be underrepresented in RefSoil. For example, RefSoil was observed to have increased representation of Firmicutes despite its low abundance in soil environments and also lacked representation of Acidobacteria and Verrucomicrobia, which are abundant in soils. Our comparison of RefSoil to soil amplicon datasets allowed us to identify targets that if cultured or sequenced would significantly increase the biodiversity represented within RefSoil. To demonstrate the opportunities to access these underrepresented targets, we employed single cell genomics in a pilot experiment to recover 14 genomes from the "most wanted" list, which improved RefSoil's representation of EMP sequences by 7% by abundance. This effort demonstrates the value of RefSoil in the guidance of future research efforts and the capability of single cell genomics as a practical means to fill the existing genomic data gaps.« less

Thermal properties of degraded lowland peat-moorsh soils

NASA Astrophysics Data System (ADS)

Gnatowski, Tomasz

2016-04-01

Soil thermal properties, i.e.: specific heat capacity (c), thermal conductivity (K), volumetric heat capacity (C) govern the thermal environment and heat transport through the soil. Hence the precise knowledge and accurate predictions of these properties for peaty soils with high amount of organic matter are especially important for the proper forecasting of soil temperature and thus it may lead to a better assessment of the greenhouse gas emissions created by microbiological activity of the peatlands. The objective of the study was to develop the predictive models of the selected thermal parameters of peat-moorsh soils in terms of their potential applicability for forecasting changes of soil temperature in degraded ecosystems of the Middle Biebrza River Valley area. Evaluation of the soil thermal properties was conducted for the parameters: specific heat capacity (c), volumetric heat capacities of the dry and saturated soil (Cdry, Csat) and thermal conductivities of the dry and saturated soil (Kdry, Ksat). The thermal parameters were measured using the dual-needle probe (KD2-Pro) on soil samples collected from seven peaty soils, representing total 24 horizons. The surface layers were characterized by different degrees of advancement of soil degradation dependent on intensiveness of the cultivation practises (peaty and humic moorsh). The underlying soil layers contain peat deposits of different botanical composition (peat-moss, sedge-reed, reed and alder) and varying degrees of decomposition of the organic matter, from H1 to H7 (von Post scale). Based on the research results it has been shown that the specific heat capacity of the soils differs depending on the type of soil (type of moorsh and type of peat). The range of changes varied from 1276 J.kg-1.K-1 in the humic moorsh soil to 1944 J.kg-1.K-1 in the low decomposed sedge-moss peat. It has also been stated that in degraded peat soils with the increasing of the ash content in the soil the value of specific heat

Calculations of microwave brightness temperature of rough soil surfaces: Bare field

NASA Technical Reports Server (NTRS)

Mo, T.; Schmugge, T. J.; Wang, J. R.

1985-01-01

A model for simulating the brightness temperatures of soils with rough surfaces is developed. The surface emissivity of the soil media is obtained by the integration of the bistatic scattering coefficients for rough surfaces. The roughness of a soil surface is characterized by two parameters, the surface height standard deviation sigma and its horizontal correlation length l. The model calculations are compared to the measured angular variations of the polarized brightness temperatures at both 1.4 GHz and 5 GHz frequences. A nonlinear least-squares fitting method is used to obtain the values of delta and l that best characterize the surface roughness. The effect of shadowing is incorporated by introducing a function S(theta), which represents the probability that a point on a rough surface is not shadowed by other parts of the surface. The model results for the horizontal polarization are in excellent agreement with the data. However, for the vertical polarization, some discrepancies exist between the calculations and data, particularly at the 1.4 GHz frequency. Possible causes of the discrepancy are discussed.

Towards a global understanding of vertical soil carbon dynamics: meta-analysis of soil 14C data

NASA Astrophysics Data System (ADS)

hatte, C.; Balesdent, J.; Guiot, J.

2012-12-01

Soil represents the largest terrestrial storage mechanism for atmospheric carbon from photosynthesis, with estimates ranging from 1600 Pg C within the top 1 meter to 2350 Pg C for the top 3 meters. These values are at least 2.5 times greater than atmospheric C pools. Small changes in soil organic carbon storage could result in feedback to atmospheric CO2 and the sensitivity of soil organic matter to changes in temperature, and precipitation remains a critical area of research with respect to the global carbon cycle. As an intermediate storage mechanism for organic material through time, the vertical profile of carbon generally shows an age continuum with depth. Radiocarbon provides critical information for understanding carbon exchanges between soils and atmosphere, and within soil layers. Natural and "bomb" radiocarbon has been used to demonstrate the importance and nature of the soil carbon response to climatic and human impacts on decadal to millennial timescales. Radiocarbon signatures of bulk, or chemically or physically fractionated soil, or even of specific organic compounds, offer one of the only ways to infer terrestrial carbon turnover times or test ecosystem carbon models. We compiled data from the literature on radiocarbon distribution on soil profiles and characterized each study according to the following categories: soil type, analyzed organic fraction, location (latitude, longitude, elevation), climate (temperature, precipitation), land use and sampling year. Based on the compiled data, soil carbon 14C profiles were reconstructed for each of the 226 sites. We report here partial results obtained by statistical analyses of portion of this database, i.e. bulk and bulk-like organic matter and sampling year posterior to 1980. We highlight here 14C vertical pattern in relationship with external parameters (climate, location and land use).

Soils at the hyperarid margin: The isotopic composition of soil carbonate from the Atacama Desert, Northern Chile

USGS Publications Warehouse

Quade, Jay; Rech, Jason A.; Latorre, Claudio; Betancourt, Julio L.; Gleeson, Erin; Kalin, Mary T.K.

2007-01-01

We evaluate the impact of exceptionally sparse plant cover (0–20%) and rainfall (2–114 mm/yr) on the stable carbon and oxygen composition of soil carbonate along elevation transects in what is among the driest places on the planet, the Atacama Desert in northern Chile. δ13C and δ18O values of carbonates from the Atacama are the highest of any desert in the world. δ13C (VPDB) values from soil carbonate range from -8.2% at the wettest sites to +7.9% at the driest. We measured plant composition and modeled respiration rates required to form these carbonate isotopic values using a modified version of the soil diffusion model of [Cerling (1984) Earth Planet. Sci. Lett.71, 229–240], in which we assumed an exponential form of the soil CO2 production function, and relatively shallow (20–30 cm) average production depths. Overall, we find that respiration rates are the main predictor of the δ13C value of soil carbonate in the Atacama, whereas the fraction C3 to C4 biomass at individual sites has a subordinate influence. The high average δ13C value (+4.1%) of carbonate from the driest study sites indicates it formed&mdahs;perhaps abiotically—in the presence of pure atmospheric CO2. δ18O (VPDB) values from soil carbonate range from -5.9% at the wettest sites to +7.3% at the driest and show much less regular variation with elevation change than δ13C values. δ18O values for soil carbonate predicted from local temperature and δ18O values of rainfall values suggest that extreme (>80% in some cases) soil dewatering by evaporation occurs at most sites prior to carbonate formation. The effects of evaporation compromise the use of δ18O values from ancient soil carbonate to reconstruct paleoelevation in such arid settings.

Induced polarization for characterizing and monitoring soil stabilization processes

NASA Astrophysics Data System (ADS)

Saneiyan, S.; Ntarlagiannis, D.; Werkema, D. D., Jr.

2017-12-01

Soil stabilization is critical in addressing engineering problems related to building foundation support, road construction and soil erosion among others. To increase soil strength, the stiffness of the soil is enhanced through injection/precipitation of a chemical agents or minerals. Methods such as cement injection and microbial induced carbonate precipitation (MICP) are commonly applied. Verification of a successful soil stabilization project is often challenging as treatment areas are spatially extensive and invasive sampling is expensive, time consuming and limited to sporadic points at discrete times. The geophysical method, complex conductivity (CC), is sensitive to mineral surface properties, hence a promising method to monitor soil stabilization projects. Previous laboratory work has established the sensitivity of CC on MICP processes. We performed a MICP soil stabilization projects and collected CC data for the duration of the treatment (15 days). Subsurface images show small, but very clear changes, in the area of MICP treatment; the changes observed fully agree with the bio-geochemical monitoring, and previous laboratory experiments. Our results strongly suggest that CC is sensitive to field MICP treatments. Finally, our results show that good quality data alone are not adequate for the correct interpretation of field CC data, at least when the signals are low. Informed data processing routines and the inverse modeling parameters are required to produce optimal results.

Characteristic variations in reflectance of surface soils

NASA Technical Reports Server (NTRS)

Stoner, E. R.; Baumgardner, M. F. (Principal Investigator)

1982-01-01

Surface soil samples from a wide range of naturally occurring soils were obtained for the purpose of studying the characteristic variations in soil reflectance as these variations relate to other soil properties and soil classification. A total 485 soil samples from the U.S. and Brazil representing 30 suborders of the 10 orders of 'Soil Taxonomy' was examined. The spectral bidirectional reflectance factor was measured on uniformly moist soils over the 0.52 to 2.32 micron wavelength range with a spectroradiometer adapted for indoor use. Five distinct soil spectral reflectance curve forms were identified according to curve shape, the presence or absence of absorption bands, and the predominance of soil organic matter and iron oxide composition. These curve forms were further characterized according to generically homogeneous soil properties in a manner similar to the subdivisions at the suborder level of 'Soil Taxonomy'. Results indicate that spectroradiometric measurements of soil spectral bidirectional reflectance factor can be used to characterize soil reflectance in terms that are meaningful to soil classification, genesis, and survey.

Hydraulic characterization of aquifers, reservoir rocks, and soils: A history of ideas

NASA Astrophysics Data System (ADS)

Narasimhan, T. N.

1998-01-01

requires that hydraulic characterization be carried out at a much finer spatial scale, for which adequate information on geometric detail is not forthcoming. Traditional methods of interpretation of field data have relied heavily on analytic solutions to specific, highly idealized initial-value problems. The availability of efficient numerical models and versatile spreadsheets of personal computers offer promising opportunities to relax many unavoidable assumptions of analytical solutions and interpret field data much more generally and with fewer assumptions. Currently, a lot of interest is being devoted to the characterization of permeability. However, all groundwater systems are transient on appropriate timescales. The dynamics of groundwater systems cannot be understood without paying attention to capacitance. Much valuable insights about the dynamic attributes of groundwater systems could be gained by long-term passive monitoring of responses of groundwater systems to barometric changes, Earth tides, and ocean tides.

Sample sizes to control error estimates in determining soil bulk density in California forest soils

Treesearch

Youzhi Han; Jianwei Zhang; Kim G. Mattson; Weidong Zhang; Thomas A. Weber

2016-01-01

Characterizing forest soil properties with high variability is challenging, sometimes requiring large numbers of soil samples. Soil bulk density is a standard variable needed along with element concentrations to calculate nutrient pools. This study aimed to determine the optimal sample size, the number of observation (n), for predicting the soil bulk density with a...

The use of sensory perception indicators for improving the characterization and modelling of total petroleum hydrocarbon (TPH) grade in soils.

PubMed

Roxo, Sónia; de Almeida, José António; Matias, Filipa Vieira; Mata-Lima, Herlander; Barbosa, Sofia

2016-03-01

This paper proposes a multistep approach for creating a 3D stochastic model of total petroleum hydrocarbon (TPH) grade in potentially polluted soils of a deactivated oil storage site by using chemical analysis results as primary or hard data and classes of sensory perception variables as secondary or soft data. First, the statistical relationship between the sensory perception variables (e.g. colour, odour and oil-water reaction) and TPH grade is analysed, after which the sensory perception variable exhibiting the highest correlation is selected (oil-water reaction in this case study). The probabilities of cells belonging to classes of oil-water reaction are then estimated for the entire soil volume using indicator kriging. Next, local histograms of TPH grade for each grid cell are computed, combining the probabilities of belonging to a specific sensory perception indicator class and conditional to the simulated values of TPH grade. Finally, simulated images of TPH grade are generated by using the P-field simulation algorithm, utilising the local histograms of TPH grade for each grid cell. The set of simulated TPH values allows several calculations to be performed, such as average values, local uncertainties and the probability of the TPH grade of the soil exceeding a specific threshold value.

Magnetism of soils applied for estimation of erosion at an agricultural land

NASA Astrophysics Data System (ADS)

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

2013-04-01

A detailed field study on small test site of agricultural land situated in loess region in Southern Moravia (Czech Republic), followed by laboratory analyses, has been carried out in order to test the applicability of magnetic methods in soil erosion estimation. The approach is based on the well-established differentiation in magnetic signature of topsoil from subsoil horizons as a result of "in situ" formation of strongly magnetic iron oxides e.g. (Maher 1986). Introducing a simple tillage homogenization model for predicting magnetic signal after uniform mixing of soil material as a result of tillage and subsequent erosion, Royall (2001) showed that magnetic susceptibility and its frequency dependence can be used to estimate soil loss. Haplic Chernozem is an original dominant soil unit in the wider area, nowadays progressively transformed into different soil units along with intensive soil erosion. The site was characterized by a flat upper part while the middle part, formed by a substantive side valley, is steeper (up to 15°). The side valley represented a major line of concentrated runoff emptying into a colluvial fan (Zadorova et al., 2011; Jaksik et al., 2011). Field measurements of magnetic susceptibility were carried out on regular grid, resulting in 101 data points. Bulk soil material for laboratory investigation was gathered from all grid points. Mass specific magnetic susceptibility χ and its frequency dependence kFD was used to estimate the significance of SP ferrimagnetic particles of pedogenic origin. Thermomagnetic analyses, hysteresis measurement and SEM were used in order to determine dominant ferrimagnetic carriers in top-soil and sub-soil layers. Strong correlation was found between the volume magnetic susceptibility (field measurement) and mass specific magnetic susceptibility measured in the laboratory (R2 = 0.80). At the same time, no correlations were found between the values of kFD and mass specific susceptibility. Values of organic carbon

Two approaches to biological decontamination of groundwater and soil polluted by aromatics-characterization of microbial populations.

PubMed

Demnerová, Katerina; Mackova, Martina; Spevákova, Veronika; Beranova, Katarina; Kochánková, Lucie; Lovecká, Petra; Ryslavá, Edita; Macek, Tomas

2005-09-01

As part of the EU project MULTIBARRIERS, six new endogenous aerobic bacterial isolates able to grow in the presence of BTmX (benzene, toluene, m-xylene) were characterized with respect to their growth specificities. Preliminary analysis included restriction fragment length polymorphism profiles and 16S rDNA sequencing. The diversity of these strains was confirmed by denaturing gradient gel electrophoresis. Additional aerobic bacterial strains were isolated from the rhizospheres of plants grown in polychlorinated biphenyl (PCB)-contaminated soils. Pot experiments were designed to show the beneficial effect of plants on the bacterial degradation of PCBs. The effect of PCB removal from soil was evaluated and bacteria isolated from three different plant species were examined for the presence of the bph operon.

Geophysical surveys combined with laboratory soil column experiments to identify and explore risk areas for soil and water pollution in feedlots

NASA Astrophysics Data System (ADS)

Espejo-Pérez, Antonio Jesus; Sainato, Claudia Mabel; Jairo Márquez-Molina, John; Giráldez, Juan Vicente; Vanderlinden, Karl

2014-05-01

Changes of land use without a correct planning may produce its deterioration with their social, economical and environmental irreversible consequences over short to medium time range. In Argentina, the expansion of soybean fields induced a reduction of the area of pastures dedicated to stockbreeding. As cattle activity is being progressively concentrated on small pens, at feedlots farms, problems of soil and water pollution, mainly by nitrate, have been detected. The characterization of the spatial and temporal variability of soil water content is very important because the mostly advective transport of solutes. To avoid intensive soil samplings, very expensive, one has to recur to geophysical exploration methods. The objective of this work was to identify risk areas within a feedlot of the NW zone of Buenos Aires Province, in Argentina through geophysical methods. The surveys were carried out with an electromagnetic induction profiler EMI-400 (GSSI) and a Time domain Reflectometry (TDR) survey of depth 0-0.10 m with soil sampling and measurement of moisture content with gravimetric method (0-1.0 m). Several trenches were dug inside the pens and also at a test site, where texture, apparent density, saturated hydraulic conductivity (Ks), electrical conductivity of the saturation paste extract and organic matter content (OM) were measured. The water retention curves for these soils were also determined. At one of the pens undisturbed soil columns were extracted at 3 locations. Laboratory analysis for 0-1.0 m indicated that soil texture was classified as sandy loam, average organic matter content (OM) was greater than 2.3% with low values of apparent density in the first 10 cm. The range of spatial dependence of data suggested that the number of soil samples could be reduced. Soil apparent electrical conductivity (ECa) and soil moisture were well correlated and indicated a clear spatial pattern in the corrals. TDR performance was acceptable to identify the spatial

Reading the Molecular Code in Soils

NASA Astrophysics Data System (ADS)

Hess, N. J.; Tfaily, M. M.; O'Brien, S. L.; Tolic, N.; Jastrow, J. D.; Amonette, J. E.

2015-12-01

There is much that we understand about the relationship between plants, microbes, soil, and water but that understanding is incomplete at the molecular scale. With advent of high throughput genomic sequencing we are beginning to appreciate the diversity of microbial community structure and function and its response to the rhythm of plant function. Through the lens of high-resolution mass spectrometry we are getting our first glimpses of the diversity of soil and pore water organic chemistry at the molecular level. In combination, these diverse data streams are revealing traces of chemical metabolic pathways. This approach promises to reveal many exciting future discoveries, shedding light into the "black box" that exists beneath our feet. In this talk we discuss our experience with the molecular characterization of soils from native prairie to restored prairie to active corn-soybean soils from the DOE funded CSiTE project in Batavia, Illinois. We focus on how common soil separation and fractionation techniques can affect the resulting molecular soil characterization by comparing whole soils to those that have been fractionated into micro- and macro-aggregates and their corresponding silt and clay fractions. When carefully utilized and interpreted these fractionation techniques can be utilized for deepening understanding of the biotic and abiotic chemical pathways effecting the organic chemistry in the different soil fractions. In highly fractionated soils we find significant differences in organic chemistry between silt and clay separates of corresponding hierarchical aggregate fractions. However the most biologically rich information resides in the whole soil. Here we see significant gradients in soil chemistry across to active agricultural to restored to native prairie soils. These results suggest a cautionary note, namely that soil fractionation prior to molecular characterization can reveal much about the "abiotic" interactions between organic molecules and

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

NASA Technical Reports Server (NTRS)

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

1990-01-01

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

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

NASA Technical Reports Server (NTRS)

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

1988-01-01

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

Probability Models Based on Soil Properties for Predicting Presence-Absence of Pythium in Soybean Roots.

PubMed

Zitnick-Anderson, Kimberly K; Norland, Jack E; Del Río Mendoza, Luis E; Fortuna, Ann-Marie; Nelson, Berlin D

2017-10-01

Associations between soil properties and Pythium groups on soybean roots were investigated in 83 commercial soybean fields in North Dakota. A data set containing 2877 isolates of Pythium which included 26 known spp. and 1 unknown spp. and 13 soil properties from each field were analyzed. A Pearson correlation analysis was performed with all soil properties to observe any significant correlation between properties. Hierarchical clustering, indicator spp., and multi-response permutation procedures were used to identify groups of Pythium. Logistic regression analysis using stepwise selection was employed to calculate probability models for presence of groups based on soil properties. Three major Pythium groups were identified and three soil properties were associated with these groups. Group 1, characterized by P. ultimum, was associated with zinc levels; as zinc increased, the probability of group 1 being present increased (α = 0.05). Pythium group 2, characterized by Pythium kashmirense and an unknown Pythium sp., was associated with cation exchange capacity (CEC) (α < 0.05); as CEC increased, these spp. increased. Group 3, characterized by Pythium heterothallicum and Pythium irregulare, were associated with CEC and calcium carbonate exchange (CCE); as CCE increased and CEC decreased, these spp. increased (α = 0.05). The regression models may have value in predicting pathogenic Pythium spp. in soybean fields in North Dakota and adjacent states.

Influence of land use on soil organic matter

NASA Astrophysics Data System (ADS)

Rogeon, H.; Lemée, L.; Chabbi, A.; Ambles, A.

2009-04-01

fractionated and derivatised (methylation and acetylation) prior to GC-MS analysis. They are mainly of plant origin from surface to 50 cm horizons (long odd chained hydrocarbons, long even chained alcohols and fatty acids) whereas they clearly have a different origin in the deepest horizons. The fatty acids fraction is of particular interest since it is possible to distinguish bacterial from plant inputs. The isotopic carbon ratio composition (delta 13C) of a whole soil gives information about the photosynthesis process. Therefore, this technique could be used to differentiate bacterial from plant inputs into the fatty acid fraction. Indeed the obtained delta 13C values of fatty acids from bacterial and plant origins are different. It is particularly interesting to notice that branched compounds (bacterial input) present higher values than linear compounds. Humic substances were obtained from IHSS (International Humic Substances Society) protocol. Contrarily to lipids, humin is less present in the arable soil (60%of the sample) than in the other soils (90%). In the case of the forest and the grassland, the increase in this refractory pool of OM with depth indicates that SOM become more resistant to biodegradation in deepest horizons. Furthermore, humic acids and humin were characterized by thermochemolysis using TMAH as alkylating agent. The major pyrolysis products of humic acids and humin are short chained (Soils and Global Change, pp 9-26 [2] Lal, R., et al., (2004), Soil carbon sequestration to mitigate climate change, Geoderma 123, 1-22. [3] IPCC, 2001. Summary for policymakers. In: Watson, R., (Ed.), Climate Change 2001: The Scientific Basis. Cambridge University Press, Cambridge, 1-20.

Characterizing agricultural soil nitrous acid (HONO) and nitric oxide (NO) emissions with their nitrogen isotopic composition

NASA Astrophysics Data System (ADS)

Chai, J.; Miller, D. J.; Guo, F.; Dell, C. J.; Karsten, H.; Hastings, M. G.

2017-12-01

Nitrous acid (HONO) is a major source of atmospheric hydroxyl radical (OH), which greatly impacts air quality and climate. Fertilized soils may be important sources of HONO in addition to nitric oxide (NO). However, soil HONO emissions are especially challenging to quantify due to huge spatial and temporal variation as well as unknown HONO chemistry. With no in-situ measurements available, soil HONO emissions are highly uncertain. Isotopic analysis of HONO may provide a tool for tracking these sources. We characterize in situ soil HONO and NO fluxes and their nitrogen isotopic composition (δ15N) across manure management and meteorological conditions during a sustainable dairy cropping study in State College, Pennsylvania. HONO and NO were simultaneously collected at hourly resolution from a custom-coated dynamic soil flux chamber ( 3 LPM) using annular denuder system (ADS) coupled with an alkaline-permanganate NOx collection system for offline isotopic analysis of δ15N with ±0.6 ‰ (HONO) and ±1.5 ‰ (NO) precision. The ADS method was tested using laboratory generated HONO flowing through the chamber to verify near 100% collection (with no isotopic fractionation) and suitability for soil HONO collection. Corn-soybean rotation plots (rain-fed) were sampled following dairy manure application with no-till shallow-disk injection (112 kg N ha-1) and broadcast with tillage incorporation (129 kg N ha-1) during spring 2017. Soil HONO fluxes (n=10) ranged from 0.1-0.6 ng N-HONO m-2 s-1, 4-28% of total HONO+NO mass fluxes. HONO and NO fluxes were correlated, with both declining during the measurement period. The soil δ15N-HONO flux weighted mean ±1σ of -15 ± 6‰ was less negative than δ15N of simultaneously collected NO (-29 ± 8‰). This can potentially be explained by fractionations associated with microbial conversion of nitrite, abiotic production of HONO from soil nitrite, and uptake and release with changing soil moisture. Our results have implications for

Relating soil pore geometry to soil water content dynamics decomposed at multiple frequencies

NASA Astrophysics Data System (ADS)

Qin, Mingming; Gimenez, Daniel; Cooper, Miguel

2016-04-01

Soil structure is a critical factor determining the response of soil water content to meteorological inputs such as precipitation. Wavelet analysis can be used to filter a signal into several wavelet components, each characterizing a given frequency. The purpose of this research was to investigate relationships between the geometry of soil pore systems and the various wavelet components derived from soil water content dynamics. The two study sites investigated were located in the state of São Paulo, Brazil. Each site was comprised of five soil profiles, the first site was situated along a 300-meter transect with about 10% slope in a tropical semi-deciduous forest, while the second one spanned 230-meter over a Brazilian savanna with a slope of about 6%. For each profile, between two to four Water Content Reflectometer CS615 (Campbell Scientific, Inc.) probes were installed according to horizonation at depths varying between 0.1 m and 2.3 m. Bulk soil, three soil cores, and one undisturbed soil block were sampled from selected horizons for determining particle size distributions, water retention curves, and pore geometry, respectively. Pore shape and size were determined from binary images obtained from resin-impregnated blocks and used to characterize pore geometry. Soil water contents were recorded at a 20-minute interval over a 4-month period. The Mexican hat wavelet was used to decompose soil water content measurements into wavelet components. The responses of wavelet components to wetting and drying cycles were characterized by the median height of the peaks in each wavelet component and were correlated with particular pore shapes and sizes. For instance, large elongated and irregular pores, largely responsible for the transmission of water, were significantly correlated with wavelet components at high frequencies (40 minutes to 48 hours) while rounded pores, typically associated to water retention, were only significantly correlated to lower frequency ranges

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

PubMed

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

2015-01-01

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

Labile pools of Pb in vegetable-growing soils investigated by an isotope dilution method and its influence on soil pH.

PubMed

Xie, Hong; Huang, Zhi-Yong; Cao, Ying-Lan; Cai, Chao; Zeng, Xiang-Cheng; Li, Jian

2012-08-01

Pollution of Pb in the surface of agricultural soils is of increasing concern due to its serious impact on the plant growth and the human health through the food chain. However, the mobility, activity and bioavailability of Pb rely mainly on its various chemical species in soils. In the present study, E and L values, the labile pools of isotopically exchangeable Pb, were estimated using the method of isotope dilution in three vegetable-growing soils. The experiments involved adding a stable enriched isotope ((206)Pb > 96%) to a soil suspension and to soils in which plants are subsequently grown, the labile pools of Pb were then estimated by measuring the isotopic composition of Pb in soil solutions and in the plant tissues, respectively. In addition, the correlation of E values and soil pH was investigated at the ranges of pH 4.5-7.0. The amount of labile Pb in soils was also estimated using different single chemical extractants and a modified BCR approach. The results showed that after spiking the enriched isotopes of (206)Pb (>96%) for 24 hours an equilibration of isotopic exchanges in soil suspensions was achieved, and the isotope ratios of (208)Pb/(206)Pb measured at that time was used for calculating the E(24 h) values. The labile pools of Pb by %E(24 h) values, ranging from 53.2% to 61.7% with an average 57%, were found to be significantly higher (p < 0.05) than the values estimated with L values, single chemical extractants and the Σ(BCR) values obtained with the BCR approach, respectively. A strong negative correlation (R(2) = 0.984) between E(24 h) values and soil pH was found in the tested soil sample. The results indicate that the %E(24 h) value can more rapidly and easily predict the labile pools of Pb in soils compared with L values, but it might be readily overestimated because of the artificial soil acidity derived from the spiked isotopic tracer and the excess of spiked enriched isotopes. The results also suggest that the amounts of Pb extracted

Soil Water Retention as Indicator for Soil Physical Quality - Examples from Two SoilTrEC European Critical Zone Observatories

NASA Astrophysics Data System (ADS)

Rousseva, Svetla; Kercheva, Milena; Shishkov, Toma; Dimitrov, Emil; Nenov, Martin; Lair, Georg J.; Moraetis, Daniel

2014-05-01

Soil water retention is of primary importance for majority of soil functions. The characteristics derived from Soil Water Retention Curve (SWRC) are directly related to soil structure and soil water regime and can be used as indicators for soil physical quality. The aim of this study is to present some parameters and relationships based on the SWRC data from the soil profiles characterising the European SoilTrEC Critical Zone Observatories Fuchsenbigl and Koiliaris. The studied soils are representative for highly productive soils managed as arable land in the frame of soil formation chronosequence at "Marchfeld" (Fuchsenbigl CZO), Austria and heavily impacted soils during centuries through intensive grazing and farming, under severe risk of desertification in context of climatic and lithological gradient at Koiliaris, Crete, Greece. Soil water retention at pF ≤ 2.52 was determined using the undisturbed soil cores (100 cm3 and 50 cm3) by a suction plate method. Water retention at pF = 4.2 was determined by a membrane press method and at pF ≥ 5.6 - by adsorption of water vapour at controlled relative humidity, both using ground soil samples. The soil physical quality parameter (S-parameter) was defined as the slope of the water retention curve at its inflection point (Dexter, 2006), determined with the obtained parameters of van Genuhten (1980) water retention equation. The S-parameter values were categorised to assess soil physical quality as follows: S < 0.020 very poor, 0.020 ≤ S < 0.035 poor, 0.035 ≤ S < 0.050 good, S ≥ 0.050 very good (Dexter, 2004). The results showed that most of the studied topsoil horizons have good physical quality according to both the S-parameter and the Plant-Available Water content (PAW), with the exception of the soils from croplands at CZO Fuxenbigl (F4, F5) which are with poor soil structure. The link between the S-parameter and the indicator of soil structure stability (water stable soil aggregates with size 1-3 mm) is not

Inversion of soil electrical conductivity data to estimate layered soil properties

USDA-ARS?s Scientific Manuscript database

CBulk apparent soil electrical conductivity (ECa) sensors respond to multiple soil properties, including clay content, water content, and salt content (i.e., salinity). They provide a single sensor value for an entire soil profile down to a sensor-dependent measurement depth, weighted by a nonlinear...

Predicting radiocaesium sorption characteristics with soil chemical properties for Japanese soils.

PubMed

Uematsu, Shinichiro; Smolders, Erik; Sweeck, Lieve; Wannijn, Jean; Van Hees, May; Vandenhove, Hildegarde

2015-08-15

The high variability of the soil-to-plant transfer factor of radiocaesium (RCs) compels a detailed analysis of the radiocaesium interception potential (RIP) of soil, which is one of the specific factors ruling the RCs transfer. The range of the RIP values for agricultural soils in the Fukushima accident affected area has not yet been fully surveyed. Here, the RIP and other major soil chemical properties were characterised for 51 representative topsoils collected in the vicinity of the Fukushima contaminated area. The RIP ranged a factor of 50 among the soils and RIP values were lower for Andosols compared to other soils, suggesting a role of soil mineralogy. Correlation analysis revealed that the RIP was most strongly and negatively correlated to soil organic matter content and oxalate extractable aluminium. The RIP correlated weakly but positively to soil clay content. The slope of the correlation between RIP and clay content showed that the RIP per unit clay was only 4.8 mmol g(-1) clay, about threefold lower than that for clays of European soils, suggesting more amorphous minerals and less micaceous minerals in the clay fraction of Japanese soils. The negative correlation between RIP and soil organic matter may indicate that organic matter can mask highly selective sorption sites to RCs. Multiple regression analysis with soil organic matter and cation exchange capacity explained the soil RIP (R(2)=0.64), allowing us to map soil RIP based on existing soil map information. Copyright © 2015 Elsevier B.V. All rights reserved.

Simulating soil-water movement through loess-veneered landscapes using nonconsilient saturated hydraulic conductivity measurements

USGS Publications Warehouse

Williamson, Tanja N.; Lee, Brad D.; Schoeneberger, Philip J.; McCauley, W. M.; Indorante, Samuel J.; Owens, Phillip R.

2014-01-01

Soil Survey Geographic Database (SSURGO) data are available for the entire United States, so are incorporated in many regional and national models of hydrology and environmental management. However, SSURGO does not provide an understanding of spatial variability and only includes saturated hydraulic conductivity (Ksat) values estimated from particle size analysis (PSA). This study showed model sensitivity to the substitution of SSURGO data with locally described soil properties or alternate methods of measuring Ksat. Incorporation of these different soil data sets significantly changed the results of hydrologic modeling as a consequence of the amount of space available to store soil water and how this soil water is moved downslope. Locally described soil profiles indicated a difference in Ksat when measured in the field vs. being estimated from PSA. This, in turn, caused a difference in which soil layers were incorporated in the hydrologic simulations using TOPMODEL, ultimately affecting how soil water storage was simulated. Simulations of free-flowing soil water, the amount of water traveling through pores too large to retain water against gravity, were compared with field observations of water in wells at five slope positions along a catena. Comparison of the simulated data with the observed data showed that the ability to model the range of conditions observed in the field varied as a function of three soil data sets (SSURGO and local field descriptions using PSA-derived Ksat or field-measured Ksat) and that comparison of absolute values of soil water storage are not valid if different characterizations of soil properties are used.

Identifying key soil cyanobacteria easy to isolate and culture for arid soil restoration

NASA Astrophysics Data System (ADS)

Roncero-Ramos, Beatriz; Ángeles Muñoz-Martín, M.; Chamizo, Sonia; Román, Raúl; Rodriguez-Caballero, Emilio; Mateo, Pilar; Cantón, Yolanda

2017-04-01

Drylands represent an important fraction of the Earth land's surface. Low cover of vascular plants characterizes these regions, and the large open areas among plants are often colonized by cyanobacteria, mosses, lichens, algae, bryophytes, bacteria and fungi, known as biocrusts. Because these communities are on or within the soil surface, they contribute to improve physicochemical properties of the uppermost soil layers and have important effects on soil fertility and stability, so they could play an important role on soil restoration. Cyanobacteria appear to be a cross component of biocrusts and they have been demonstrated to enhance water availability, soil fertility (fixing atmospheric C and N), and soil aggregation (thanks to their filamentous morphology and the exopolysaccharides they excrete), and significantly reduce water and wind erosion. Besides, they are able to tolerate high temperatures and UV radiation. All these features convert cyanobacteria in pioneer organisms capable of colonizing degraded soils and may be crucial in facilitating the succession of more developed organisms such as vascular plants. Therefore, the use of native cyanobacteria, already adapted to site environmental conditions, could guarantee a successful restoration approach of degraded soils. However, previous to their application for soil restoration, the most representative species inhabiting these soils should be identified. The objective of this study was to identify (morphologically and genetically) and isolate representative native cyanobacteria species from arid soils in SE Spain, characterized for being easily isolated and cultured with the aim of using them to inoculate degraded arid soil. We selected two study areas in Almería, SE Spain, where biocrust cover most of the open spaces between plants: El Cautivo experimental site located in the Tabernas desert and a limestone quarry located at the southeastern edge of the Gádor massif. The first site is characterized by

Determination of resilient modulus values for typical plastic soils in Wisconsin.

DOT National Transportation Integrated Search

2011-09-01

"The objectives of this research are to establish a resilient modulus test results database and to develop : correlations for estimating the resilient modulus of Wisconsin fine-grained soils from basic soil properties. A : laboratory testing program ...

Predicting Soluble Nickel in Soils Using Soil Properties and Total Nickel.

PubMed

Zhang, Xiaoqing; Li, Jumei; Wei, Dongpu; Li, Bo; Ma, Yibing

2015-01-01

Soil soluble nickel (Ni) concentration is very important for determining soil Ni toxicity. In the present study, the relationships between soil properties, total and soluble Ni concentrations in soils were developed in a wide range of soils with different properties and climate characteristics. The multiple regressions showed that soil pH and total soil Ni concentrations were the most significant parameters in predicting soluble Ni concentrations with the adjusted determination coefficients (Radj2) values of 0.75 and 0.68 for soils spiked with soluble Ni salt and the spiked soils leached with artificial rainwater to mimic field conditions, respectively. However, when the soils were divided into three categories (pH < 7, 7-8 and > 8), they obtained better predictions with Radj2 values of 0.78-0.90 and 0.79-0.94 for leached and unleached soils, respectively. Meanwhile, the other soil properties, such as amorphous Fe and Al oxides and clay, were also found to be important for determining soluble Ni concentrations, indicating that they were also presented as active adsorbent surfaces. Additionally, the whole soil speciation including bulk soil properties and total soils Ni concentrations were analyzed by mechanistic speciation models WHAM VI and Visual MINTEQ3.0. It was found that WHAM VI provided the best predictions for the soils with pH < 7, was relatively reasonable for pH 7 to 8, and gave an overestimation for pH > 8. The Visual MINTEQ3.0 could provide better estimation for pH < 8 and meanwhile quite reasonable results for pH > 8. These results indicated the possibility and applicability of these models to predict soil soluble Ni concentration by soil properties.

Spatiotemporal characterization of soil moisture fields in agricultural areas using cosmic-ray neutron probes and data fusion

NASA Astrophysics Data System (ADS)

Franz, Trenton; Wang, Tiejun

2015-04-01

Approximately 40% of global food production comes from irrigated agriculture. With the increasing demand for food even greater pressures will be placed on water resources within these systems. In this work we aimed to characterize the spatial and temporal patterns of soil moisture at the field-scale (~500 m) using the newly developed cosmic-ray neutron rover near Waco, NE USA. Here we mapped soil moisture of 144 quarter section fields (a mix of maize, soybean, and natural areas) each week during the 2014 growing season (May to September). The 12 by 12 km study domain also contained three stationary cosmic-ray neutron probes for independent validation of the rover surveys. Basic statistical analysis of the domain indicated a strong relationship between the mean and variance of soil moisture at several averaging scales. The relationships between the mean and higher order moments were not significant. Scaling analysis indicated strong power law behavior between the variance of soil moisture and averaging area with minimal dependence of mean soil moisture on the slope of the power law function. In addition, we combined the data from the three stationary cosmic-ray neutron probes and mobile surveys using linear regression to derive a daily soil moisture product at 1, 3, and 12 km spatial resolutions for the entire growing season. The statistical relationships derived from the rover dataset offer a novel set of observations that will be useful in: 1) calibrating and validating land surface models, 2) calibrating and validating crop models, 3) soil moisture covariance estimates for statistical downscaling of remote sensing products such as SMOS and SMAP, and 4) provide daily center-pivot scale mean soil moisture data for optimal irrigation timing and volume amounts.

Characterizing soil erosion potential using electrical resistivity imaging : technical summary.

DOT National Transportation Integrated Search

2017-04-01

The erosion rate, or erodibility, of soil depends on many soil characteristics : including: plasticity, water content, grain size, percent clay, compaction, and shear : strength. Many of these characteristics also influence soil in situ bulk electric...

Characterizing soil erosion potential using electrical resistivity imaging : final report.

DOT National Transportation Integrated Search

2017-04-01

The erosion rate, or erodibility, of soil depends on many soil characteristics including: plasticity, : water content, grain size, percent clay, compaction, and shear strength. Many of these characteristics also : influence soil in situ bulk electric...

NEGLECTED COMPONENTS OF BIODIVERSITY: SOIL ORIBATID MITES, COMMUNITY STRUCTURE AND SOIL RECOVERY

EPA Science Inventory

Oribatid mites are an abundant and diverse component of soils in regional pine forests, and are valuable in characterizing the biodiversity of these forested lands. We sampled oribatid mites using soil cores and leaf litterbags, in young aggrading forest stands. Comparing these...

Soil amendments effects on radiocesium translocation in forest soils.

PubMed

Sugiura, Yuki; Ozawa, Hajime; Umemura, Mitsutoshi; Takenaka, Chisato

2016-12-01

We conducted an experiment to investigate the potential of phytoremediation by soil amendments in a forest area. To desorb radiocesium ( 137 Cs) from variable charges in the soil, ammonium sulfate (NH 4 + ) and elemental sulfur (S) (which decrease soil pH) were applied to forest soil collected from contaminated area at a rate of 40 and 80 g/m 2 , respectively. A control condition with no soil treatment was also considered. We defined four groups of aboveground conditions: planted with Quercus serrata, planted with Houttuynia cordata, covered with rice straw as litter, and unplanted/uncovered (control). Cultivation was performed in a greenhouse with a regular water supply for four months. Following elemental sulfur treatment, soil pH values were significantly lower than pH values following ammonium sulfate treatment and no treatment. During cultivation, several plant species germinated from natural seeds. No clear differences in aboveground tissue 137 Cs concentrations in planted Q. serrata and H. cordata were observed among the treatments. However, aboveground tissue 137 Cs concentration values in the germinated plants following elemental sulfur treatment were higher than the values following the ammonium sulfate treatment and no treatment. Although biomass values for Q. serrata, H. cordata, and germinated plants following elemental sulfur treatment tended to be low, the total 137 Cs activities in the aboveground tissue of germinated plants were higher than those following ammonium sulfate treatment and no treatment in rice straw and unplanted conditions. Although no significant differences were observed, 137 Cs concentrations in rice straw following ammonium sulfate and elemental sulfur treatments tended to be higher than those in the control case. The results of this study indicate that elemental sulfur lowers the soil pH for a relatively long period and facilitates 137 Cs translocation to newly emerged and settled plants or litter, but affects plant growth in

An Evaluation of Vegetation Influences on Infiltration in Hawaiian Soils

NASA Astrophysics Data System (ADS)

Perkins, K. S.; Stock, J. D.; Nimmo, J. R.

2016-12-01

Changes in vegetation communities such as removing trees, introducing grazing ungulates, and replacing native plants with invasive species have substantially altered soil infiltration processes and rates and therefore runoff, erosion, and aquifer recharge. We hypothesize that broad vegetation communities can be characterized by distributions of saturated hydraulic conductivity (Kfs). We used 300 field measurements of hydraulic conductivity from six sites on five of the Hawaiian Islands to show this effect. We analyzed the data using three broad ecosystem categories: grasses, trees and shrubs, or bare soil. The soils of each site have co-evolved with past and present ecological community without significant mechanical disturbance by agriculture or other human activities. Geometric mean values Kfs are 203 mm/h for soils hosting trees and shrubs, 50 mm/h for grasses, and 13 mm/h for bare soil. Differences are statistically significant at the 95% confidence level. These examples show that it is feasible to make maps of Kfs based on field and ecosystem data. These ecosystem trends can be used to estimate ongoing changes to runoff and recharge from climate and land use change.

Mineralogy and geochemistry of soils from glass houses and solariums

NASA Astrophysics Data System (ADS)

Bulgariu, Dumitru; Filipov, Feodor; Rusu, Constantin; Bulgariu, Laura

2010-05-01

very difficult. Practically, each type of soil from this category has distinct pedological and chemical-mineralogical characteristics, mostly determined by the nature of parental material and by the exploitation technologies. Concerning to the pedogeochemistry of soils from glasshouses have not yet been written summary studies, most existing papers from literature are in fact, case studies of particular situations. The deficit of information from this field, together with the ambiguity of pedogenetical characters of diagnostic, makes difficult the unitary characterization of soils from glasshouses. Characteristic for the soils from glass houses are the intense modifications of soil profile, the large variability of mineralogy and chemistry, and the salinization processes of superior horizons. From chemical point of view, the soils from glass houses is characterized by high values of bases saturation, accessible phosphorus and ration between humic and fulvic acids. From mineralogical point of view, the soils from glass houses studied is characterized by a high heterogeneity degree, both as contents, and as occurrence and distribution forms of mineral and organic components in profile. Predominant quantitatively are clay minerals and as variety, the crystalline forms are most abundant. As regard the clay minerals type, the kaolin and illites have dominant weights in comparison with smectites and the other mineral components. Acknowledgments The authors would like to acknowledge the financial support from Romanian Ministry of Education and Research (Project PNCDI 2-D5 no. 51045/07).

Soil tension mediates isotope fractionation during soil water evaporation

NASA Astrophysics Data System (ADS)

Gaj, Marcel; McDonnell, Jeffrey

2017-04-01

Isotope tracing of the water cycle is increasing in its use and usefulness. Many new studies are extracting soil waters and relating these to streamflow, groundwater recharge and plant transpiration. Nevertheless, unlike isotope fractionation factors from open water bodies, soil water fractionation factors are poorly understood and until now, only empirically derived. In contrast to open water evaporation where temperature, humidity and vapor pressure gradient define fractionation (as codified in the well-known Craig and Gordon model), soil water evaporation includes additionally, fractionation by matrix effects. There is yet no physical explanation of kinetic and equilibrium fraction from soil water within the soil profile. Here we present a simple laboratory experiment with four admixtures of soil grain size (from sand to silt to clay). Oven-dried samples were spiked with water of known isotopic composition at different soil water contents. Soils were then stored in sealed bags and the headspace filled with dry air and allowed to equilibrate for 24hours. Isotopic analysis of the headspace vapor was done with a Los Gatos Inc. water vapor isotope analyzer. Soil water potential of subsamples were measured with a water potential meter. We show for the first time that soil tension controls isotope fractionation in the resident soil water. Below a Pf 3.5 the δ-values of 18O and 2H of the headspace vapor is more positive and increases with increasing soil water potential. Surprisingly, we find that the relationship between soil tension and equilibrium fractionation is independent of soil type. However, δ-values of each soil type plot along a distinct evaporation line. These results indicate that equilibrium fractionation is affected by soil tension in addition to temperature. Therefore, at high soil water tension (under dry conditions) equilibrium fractionation is not consistent with current empirical formulations that ignore these effects. These findings may have

Soil water repellency of the artificial soil and natural soil in rocky slopes as affected by the drought stress and polyacrylamide.

PubMed

Chen, Zhang; Wang, Ruixin; Han, Pengyuan; Sun, Hailong; Sun, Haifeng; Li, Chengjun; Yang, Lixia

2018-04-01

Soil water repellency (SWR) causes reduced soil water storage, enhanced runoff and reduced ecosystem productivity. Therefore, characterization of SWR is a prerequisite for effective environmental management. SWR has been reported under different soils, land uses and regions of the world, particularly in forest land and after wildfires; however, the understanding of this variable in the artificial soil of rocky slope eco-engineering is still rather limited. This study presented the characterization of SWR in the artificial soil affected by the polyacrylamide (PAM) and drought stress. There were two molecular weights of PAM, and the CK was without PAM application. Three types of soil were studied: natural soil and two types of artificial soil which have been sprayed for 1y and 5y, respectively. The drought stress experiments had three drought gradients, lasted for three weeks. Water repellency index (WRI) and soil-water contact angle (β) were determined using intrinsic sorptivity method by measuring the water sorptivity (S W ) and ethanol sorptivity (S E ) in all soil samples. The results showed that (1) Polyacrylamide treatments significantly increased S W by 3% to 38%, and reduced S E by 1% to 15%, WRI by 6% to 38%, β by 3% to 23% compared to the control group. Polyacrylamide treatments also increased water-stable aggregates content and total porosity by 22% to 33%, 11% to 20% relative to the control, while PAM with a higher molecular weight performed best. (2) The interaction between PAM and drought stress had a significant effect on WRI and β for all soil types (P<0.01) while it only had a significant effect on S W and S E for the artificial soil (P<0.01). (3) The artificial soil had a greater WRI and β than the natural soil. Copyright © 2017 Elsevier B.V. All rights reserved.

Spatial variability of specific surface area of arable soils in Poland

NASA Astrophysics Data System (ADS)

Sokolowski, S.; Sokolowska, Z.; Usowicz, B.

2012-04-01

Evaluation of soil spatial variability is an important issue in agrophysics and in environmental research. Knowledge of spatial variability of physico-chemical properties enables a better understanding of several processes that take place in soils. In particular, it is well known that mineralogical, organic, as well as particle-size compositions of soils vary in a wide range. Specific surface area of soils is one of the most significant characteristics of soils. It can be not only related to the type of soil, mainly to the content of clay, but also largely determines several physical and chemical properties of soils and is often used as a controlling factor in numerous biological processes. Knowledge of the specific surface area is necessary in calculating certain basic soil characteristics, such as the dielectric permeability of soil, water retention curve, water transport in the soil, cation exchange capacity and pesticide adsorption. The aim of the present study is two-fold. First, we carry out recognition of soil total specific surface area patterns in the territory of Poland and perform the investigation of features of its spatial variability. Next, semivariograms and fractal analysis are used to characterize and compare the spatial variability of soil specific surface area in two soil horizons (A and B). Specific surface area of about 1000 samples was determined by analyzing water vapor adsorption isotherms via the BET method. The collected data of the values of specific surface area of mineral soil representatives for the territory of Poland were then used to describe its spatial variability by employing geostatistical techniques and fractal theory. Using the data calculated for some selected points within the entire territory and along selected directions, the values of semivariance were determined. The slope of the regression line of the log-log plot of semi-variance versus the distance was used to estimate the fractal dimension, D. Specific surface area