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Sample records for fill-soft soil system

  1. Multiplexed hydraulic valve actuation using ionic liquid filled soft channels and Braille displays

    NASA Astrophysics Data System (ADS)

    Gu, Wei; Chen, Hao; Tung, Yi-Chung; Meiners, Jens-Christian; Takayama, Shuichi

    2007-01-01

    Pneumatic actuation with multilayer soft lithography enables operation of up to thousands of valves in parallel using far fewer control lines. However, it is dependent on macroscopic switches and external pressure sources that require interconnects and limit portability. The authors present a more portable and multiplexed valve actuation strategy that uses a grid of mechanically actuated Braille pins to hydraulically, rather than pneumatically, deform elastic actuation channels that act as valves. Experimental and theoretical analyses show that the key to reliable operation of the hydraulic system is the use of nonvolatile ionic liquids as the hydraulic fluid.

  2. Advancing Towards a Universal Soil Classification System

    NASA Astrophysics Data System (ADS)

    Owens, Phillip R.; Hempel, Jon; Micheli, Erika; McBratney, Alex

    2014-05-01

    Within the variability of soils across the globe, there are common soil attributes that pedologists have used to group soil within taxonomic classifications. Classification systems are necessary for the communication of information about soils. There are many national classification systems used within designated countries and two classification systems used globally, the US Soil Taxonomy and the World Reference Base. There is a great need for soil scientists to develop one common language or taxonomic system to communicate information within soil science as well as to other scientists in other disciplines. The International Union of Soil Sciences Working Group for Universal Soil Classification was officially established by an IUSS Council decision in August of 2010 at the World Congress of Soil Science in Brisbane, Australia. The charge for the Working Group includes development of common standards for methods and terminology in soil observations and investigations and the development of a universal soil classification system. The Universal Soil Classification Working Group was established and the initial meeting was held at Purdue University in West Lafayette, Indiana USA. The Working Group has evaluated the current national systems and the two international systems to identify gaps in knowledge. Currently, it was determined that gaps in knowledge exists in cold soil, hydromorphic, salt affected, anthropengic, and tropical soil groups. Additionally, several members of the Working Group have utilized taxonomic distance calculations from large databases to determine the clusters of similar taxonomic groupings utilizing the classification. Additionally, the databases are being used to make allocations into logical groups to recognize "Great Soil Groups". The great soil groups will be equivalent to great groups level from Soil Taxonomy along with similar levels in the World Reference Base, Australian Soil Classification and other defined soil classification systems

  3. Ash in the Soil System

    NASA Astrophysics Data System (ADS)

    Pereira, P.

    2012-04-01

    , climate/meteorological conditions after the ash spread/fire and soil background characteristics. In addition, after the fire heating can change soil original properties increasing the complexity of the ash effects on soil properties. After fire, ash is highly dynamic and very easily transported by wind until the first rains. When wetted, ash compacts and binds onto soil surface, and wind has low capacity to transport it. The post-rain ash dynamic is influenced by water erosion (in slope areas), infiltration into soil profile and vegetation recuperation. This means that ash produced in one place will have implications in other areas, including not burned areas (e.g wind transport and water erosion). This is a clear indication that ash effects go much further than the fire affected area. Due the heterogeneity of soil and ash properties and their dynamic across the landscape, the impacts of ash on soil system can be diverse, producing a mosaic of different effects and responses after ash treatment and/ or fire. In this communication it will be presented and discussed the advances and scientific development of ash effects and dynamic in soil system.

  4. DEMONSTRATION BULLETIN: SOIL WASHING SYSTEM - BIOTROL, INC.

    EPA Science Inventory

    The three component technologies of the BioTrol Soil Washing System (BSWS). Tested in the SITE demonstration were a Soil Washer (SW), and Aqueous Treatment System (ATS), and a Slurry Bio-Reactor (SBR). The Soil Washer operates on the principle that a significant fraction of the...

  5. Soil Water and Temperature System (SWATS) Handbook

    SciTech Connect

    Bond, D

    2005-01-01

    The soil water and temperature system (SWATS) provides vertical profiles of soil temperature, soil-water potential, and soil moisture as a function of depth below the ground surface at hourly intervals. The temperature profiles are measured directly by in situ sensors at the Central Facility and many of the extended facilities of the SGP climate research site. The soil-water potential and soil moisture profiles are derived from measurements of soil temperature rise in response to small inputs of heat. Atmospheric scientists use the data in climate models to determine boundary conditions and to estimate the surface energy flux. The data are also useful to hydrologists, soil scientists, and agricultural scientists for determining the state of the soil.

  6. Soil fauna community in the black soil of northeast China under different conservation tillage systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil fauna is an important component in soil ecosystem. Through the soil moisture changes, soil environment is changed under different tillage systems, and then the population of soil fauna also is changed. This study tested whether conservation tillage or conventional tillage (CT) of black soil fie...

  7. Nonlinear model for building-soil systems

    SciTech Connect

    McCallen, D.B.; Romstad, K.M.

    1994-05-01

    A finite-element based, numerical analysis methodology has been developed for the nonlinear analysis of building-soil systems. The methodology utilizes a reduced-order, nonlinear continuum model to represent the building, and the soil is represented with a simple nonlinear two-dimensional plane strain finite element. The foundation of the building is idealized as a rigid block and the interface between the soil and the foundation is modeled with an interface contract element. The objectives of the current paper are to provide the theoretical development of the system model, with particular emphasis on the modeling of the foundation-soil contact, and to demonstrate the special-purpose finite-element program that has been developed for nonlinear analysis of the building-soil system. Examples are included that compare the results obtained with the special-purpose program with the results of a general-purpose nonlinear finite-element program.

  8. Effect of soiling in CPV systems

    SciTech Connect

    Vivar, M.; Herrero, R.; Anton, I.; Martinez-Moreno, F.; Moreton, R.; Sala, G.

    2010-07-15

    The effect of soiling in flat PV modules has been already studied, causing a reduction of the electrical output of 4% on average. For CPV's, as far as soiling produces light scattering at the optical collector surface, the scattered rays should be definitively lost because they cannot be focused onto the receivers again. While the theoretical study becomes difficult because soiling is variable at different sites, it becomes easier to begin the monitoring of the real field performance of concentrators and then raise the following question: how much does the soiling affect to PV concentrators in comparison with flat panels?' The answers allow to predict the PV concentrator electrical performance and to establish a pattern of cleaning frequency. Some experiments have been conducted at the IES-UPM and CSES-ANU sites, consisting in linear reflective concentration systems, a point focus refractive concentrator and a flat module. All the systems have been measured when soiled and then after cleaning, achieving different increases of I{sub SC}. In general, results show that CPV systems are more sensitive to soiling than flat panels, accumulating losses in I{sub SC} of about 14% on average in three different tests conducted at IES-UPM and CSES-ANU test sites in Madrid (Spain) and Canberra (Australia). Some concentrators can reach losses up to 26% when the system is soiled for 4 months of exposure. (author)

  9. National Soil Information System in Turkey

    NASA Astrophysics Data System (ADS)

    Emrah Erdogan, Hakki; Sahin, Mehmet; Sahin, Yuksel

    2013-04-01

    Land consolidation (LC) represents complexity if management, legal, economic and technical procedures realized in order to adjust the land structure according to actual human preferences and needs. It includes changes in ownership rights to land and other real estate property, exchange of parcels among owners, changes in parcel borders, parcel size and shape, joining and dividing of parcels, changes in land use, construction works as roads, bridges, water changes etc.. Since the subject of LC is agricultural lands, the quality of consolidation depends on the quality of soil data. General Directorate of Agrarian Reform (GDAR) is the responsible institution on land consolidation whole of Turkey. Under GDAR, National Soil Information System (NSIS) has been build up with base soil data in relevant scale (1:5000). NSIS contain detailed information on soil chemical and physical properties, current land use, parent material, land capability class, Storie Index Values. SI were used on land consolidation, land use planning and farm development services. LCC was used for land distribution, rental land; define of village settlement, consolidation, expropriation, reconstruction, reclamation, non-agricultural usage. LCC were also specified to subclasses in four different limited factors as i) flow and erosion risk ii) requirement of drainage and soil moisture iii) Limits of soil tillage and root (shallow soils, low water retention capacity, stony, salty .etc) iv) climatic limits. In this study, digital soil survey and mapping project located in Yumurtalik, Adana is presented as an example of NSIS data structure. The project cover an area of 45709 ha that include crop lands as an area of 28528 ha and other land use (urban, roads..etc) as an area of 17181 ha. Soil profiles were described in 45 different points and totally 1279 soil samples were collected in field study and the check bore hole were made in 3170 points.

  10. Zero Tillage cotton systems and soil quality

    NASA Astrophysics Data System (ADS)

    Landers, J. N.; de Freitas, P. L.

    2012-04-01

    Monocropping in cotton production systems negates the benefits of zero tillage. With cotton in a 3-year rotation including other summer and cover crops, such as soybeans and intensive-rooting Brachiaria spp., research on sandy soils in Bahia improved soil fertility, structure and biological activity. Cotton is a deep tap-rooted crop, sensitive to physical and chemical impediments to root development; this has engendered a paradigm of heavy soil preparation operations to remove these. But, ZT can overcome such obstacles, allowing the cotton crop to benefit from cost reductions and a number of other benefits, especially erosion control.. Soil quality has three principal dimensions. Maximum yields only occur when soil fertility, structure and biological activity are in balance. Under Zero Tillage management of Brazilian soils, the processes of nutrient availability, nutrient cycling and efficiency result from increasing SOM and higher CEC. ZT system fertility is also strongly influenced by total annual aerial and root biomass generation; C:N ratios of the biomass, changes in aeration in residue breakdown processes (for roots, dependent on internal drainage), reduced fixation of Phosphorus fertilizers, the possibility of surface application of P and K, use of deep-rooted cover crops to re-cycle nutrients and deleterious effects of over-liming. Soil physical parameters undergo a transformation : greater water holding capacity, a small increase in bulk density (ameliorated by a reversal of soil aggregate breakdown inherent to conventional tillage by the binding action of root exudates and fungal hyphae), enhanced particle aggregate size protects SOM from oxidation; old root holes create semi-permanent macro-pores which facilitate rooting, aeration and rainfall infiltration.. Soil life of all types benefits from ZT management and contributes to soil fertility and structural improvements, plus enhancing certain biological controls of pathogenic organisms and allelopathic

  11. The Sand Land Soil System and Society

    NASA Astrophysics Data System (ADS)

    Mahjoory, R. A.

    Worldwide arid soils such as Latterites from African Savannas to the Xeralfs and Xererts of the Mediterranean Basin Ortents and Orthids of Asian Deserts are uniquely different in their strategic roles for utilizing the land in places where a delicate balance between annual climatic cycles and general trends toward desertification predominate Arid lands cover 1 3 of global land surface and contain irreplaceable natural resources with potential productivity of meeting the demands of more than two billion people and serving as sources and sinks of atmospheric CO2 to combat global warming The soil system in these arid areas are being degraded underutilized and kept in a stage of obliviousness due to inadequate public literacy and most importantly in-sufficient scientific evaluations based on pedology and soil taxonomy standards Implementation of food security projects and sustainable development programs on randomly selected sites and assessment of land degradation worldwide by powerful computers and satellite imagery techniques without field work and identification of Representative Soil Units are data producing and grant attracting but counter productive We live in a world in which there is an order out there and things are precisely measured and categorized for efficient utilization Why not the soils mainly in arid areas How we could generalize the world of soils under our feet by concept of soils are the same Expansion of educational programs quantification of multiple ecosystems within the arid regions through detailed and correlated

  12. Genesis Eco Systems, Inc. soil washing process

    SciTech Connect

    Cena, R.J.

    1994-10-11

    The Genesis soil washing system is an integrated system of modular design allowing for maximum material handling capabilities, with optimized use of space for site mobility. The Surfactant Activated Bio-enhanced Remediation Equipment-Generation 1 (SABRE-1, Patent Applied For) modification was developed specifically for removing petroleum byproducts from contaminated soils. Scientifically formulated surfactants, introduced by high pressure spray nozzles, displace the contaminant from the surface of the soil particles into the process solution. Once the contaminant is dispersed into the liquid fraction of the process, it is either mechanically removed, chemically oxidized, or biologically oxidized. The contaminated process water is pumped through the Genesis Biosep (Patent Applied For) filtration system where the fines portion is flocculated, and the contaminant-rich liquid portion is combined with an activated mixture of nutrients and carefully selected bacteria to decompose the hydrocarbon fraction. The treated soil and dewatered fines are transferred to a bermed stockpile where bioremediation continues during drying. The process water is reclaimed, filtered, and recycled within the system.

  13. Tillage system affects microbiological properties of soil

    NASA Astrophysics Data System (ADS)

    Delgado, A.; de Santiago, A.; Avilés, M.; Perea, F.

    2012-04-01

    Shannon (H') and Gini (1-G) diversity index of microbial communities were determined in soil samples (0-10 cm depth) taken in autumn 2009. All the enzymatic activities and the biomass estimated by viable cell counting were significantly higher under no-till than under conventional tillage. However, only fluorescents pseudomonas population was increased under no-till, meanwhile oligotrophic bacteria and actinomycetes populations were higher with conventional tillage than with no-till. Overall, there was a higher use all the group of carbon sources used in the BiologR test with conventional tillage than with no-till, by except amines and phenols which showed non-significant differences. This reveals different physiological profiles in the microbial communities under both tillage systems. The Gini diversity was significantly lower with no-till than with conventional tillage. It can be concluded that no-till increases microbial biomass in soil and subsequently enzymatic activities likely ascribed to an increased organic matter content. Under low availability of hydrocarbon sources in soil due to conventional tillage, which promotes a decrease in the organic matter content of the soil, populations of oligotrophods and the diversity of microbial communities are increased. Under these conditions, there must not be dominant carbon sources promoting the selection of microorganisms with a given physiological profile. The reduced hydrocarbon availability and the higher diversity contribute to explain the increased use of carbon sources used in Biolog with conventional tillage than with no-till.

  14. A fluid-filled soft robot that exhibits spontaneous switching among versatile spatiotemporal oscillatory patterns inspired by the true slime mold.

    PubMed

    Umedachi, Takuya; Idei, Ryo; Ito, Kentaro; Ishiguro, Akio

    2013-01-01

    Behavioral diversity is an essential feature of living systems, enabling them to exhibit adaptive behavior in hostile and dynamically changing environments. However, traditional engineering approaches strive to avoid, or suppress, the behavioral diversity in artificial systems to achieve high performance in specific environments for given tasks. The goals of this research include understanding how living systems exhibit behavioral diversity and using these findings to build lifelike robots that exhibit truly adaptive behaviors. To this end, we have focused on one of the most primitive forms of intelligence concerning behavioral diversity, namely, a plasmodium of true slime mold. The plasmodium is a large amoeba-like unicellular organism that does not possess any nervous system or specialized organs. However, it exhibits versatile spatiotemporal oscillatory patterns and switches spontaneously between these. Inspired by the plasmodium, we built a mathematical model that exhibits versatile oscillatory patterns and spontaneously transitions between these patterns. This model demonstrates that, in contrast to coupled nonlinear oscillators with a well-designed complex diffusion network, physically interacting mechanosensory oscillators are capable of generating versatile oscillatory patterns without changing any parameters. Thus, the results are expected to shed new light on the design scheme for lifelike robots that exhibit amazingly versatile and adaptive behaviors. PMID:23186349

  15. A fluid-filled soft robot that exhibits spontaneous switching among versatile spatiotemporal oscillatory patterns inspired by the true slime mold.

    PubMed

    Umedachi, Takuya; Idei, Ryo; Ito, Kentaro; Ishiguro, Akio

    2013-01-01

    Behavioral diversity is an essential feature of living systems, enabling them to exhibit adaptive behavior in hostile and dynamically changing environments. However, traditional engineering approaches strive to avoid, or suppress, the behavioral diversity in artificial systems to achieve high performance in specific environments for given tasks. The goals of this research include understanding how living systems exhibit behavioral diversity and using these findings to build lifelike robots that exhibit truly adaptive behaviors. To this end, we have focused on one of the most primitive forms of intelligence concerning behavioral diversity, namely, a plasmodium of true slime mold. The plasmodium is a large amoeba-like unicellular organism that does not possess any nervous system or specialized organs. However, it exhibits versatile spatiotemporal oscillatory patterns and switches spontaneously between these. Inspired by the plasmodium, we built a mathematical model that exhibits versatile oscillatory patterns and spontaneously transitions between these patterns. This model demonstrates that, in contrast to coupled nonlinear oscillators with a well-designed complex diffusion network, physically interacting mechanosensory oscillators are capable of generating versatile oscillatory patterns without changing any parameters. Thus, the results are expected to shed new light on the design scheme for lifelike robots that exhibit amazingly versatile and adaptive behaviors.

  16. Wavelet-based image analysis system for soil texture analysis

    NASA Astrophysics Data System (ADS)

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

    2003-05-01

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

  17. Regulatory guidance on soil cover systems

    SciTech Connect

    Kane, J.D.

    1991-12-31

    The US Nuclear Regulatory Commission (NRC) in September 1991, completed revisions to 14 sections of the Standard Review Plan (SRP) for the Review of a License Application for a Low-Level Radioactive Waste Disposal Facility. The major purposes of the SRP are to ensure the quality and uniformity of the NRC staff`s safety reviews, and to present a well-defined base from which to evaluate the acceptability of information and data provided in the Safety Analysis Report (SAR) portion of the license application. SRP 3.2, entitled, Design Considerations for Normal and Abnormal/Accident Conditions, was one of the sections that was revised by the NRC staff. This revision was completed to provide additional regulatory guidance on the important considerations that need to be addressed for the proper design and construction of soil cover systems that are to be placed over the LLW. The cover system over the waste is acknowledged to be one of the most important engineered barriers for the long-term stable performance of the disposal facility. The guidance in revised SRP 3.2 summarizes the previous efforts and recommendations of the US Army Corps of Engineers (COE), and a peer review panel on the placement of soil cover systems. NRC published these efforts in NUREG/CR-5432. The discussions in this paper highlight selected recommendations on soil cover issues that the NRC staff considers important for ensuring the safe, long-term performance of the soil cover systems. The development phases to be discussed include: (1) cover design; (2) cover material selection; (3) laboratory and field testing; (4) field placement control and acceptance; and (5) penetrations through the constructed covers.

  18. Grey water treatment by the slanted soil system with unsorted soil media.

    PubMed

    Ushijima, Ken; Tanaka, Erina; Suzuki, Laís Yuko; Hijikata, Nowaki; Funamizu, Naoyuki; Ito, Ryusei

    2015-01-01

    This study evaluated the performance of unsorted soil media in the slanted soil treatment system, in terms of removal efficiency in suspended solids (SS), chemical oxygen demand (COD), linear alkylbenzene sulphonate (LAS) and Escherichia coli, and lifetime until clogging occurs. Unsorted soil performed longer lifetime until clogging than sorted fine soil. Removal of SS, COD, and LAS also performed same or better level in unsorted soil than fine soil. As reaction coefficients of COD and LAS were described as a function of the hydraulic loading rate, we can design a slanted soil system according to the expected hydraulic loading rate and the targeted level of COD or LAS in effluent. Regarding bacteria removal, unsorted soil performed sufficient reduction of E. coli for 5 weeks; however, the removal process occurred throughout all four chambers, while that of fine soil occurred in one to two chambers.

  19. Soil carbon and soil organic matter quality in soil size fractions from crop and livestock systems in Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton based rotations and monocultures in the Southern High Plains have resulted in soil quality degradation because the semiarid environment combined with low crop residue returns has diminished soil C. Integrated crop-livestock systems and no-till based rotations can increase soil C when used as ...

  20. Hydrologic modeling of soil water storage in landfill cover systems

    SciTech Connect

    Barnes, F.J.; Rodgers, J.C.

    1987-01-01

    The accuracy of modeling soil water storage by two hydrologic models, CREAMS and HELP, was tested by comparing simulation results with field measurements of soil moisture in eight experimental landfill cover systems having a range of well-defined soil profiles and vegetative covers. Regression analysis showed that CREAMS generally represented soil moisture more accurately than HELP simulations. Soil profiles that more closely resembled natural agricultural soils were more accurately modeled than highly artificial layered soil profiles. Precautions for determining parameter values for model input and for interpreting simulation results are discussed.

  1. Evaluation of soil quality indicators in paddy soils under different crop rotation systems

    NASA Astrophysics Data System (ADS)

    Nadimi-Goki, Mandana; Bini, Claudio; Haefele, Stephan; Abooei, Monireh

    2013-04-01

    Evaluation of soil quality indicators in paddy soils under different crop rotation systems Soil quality, by definition, reflects the capacity to sustain plant and animal productivity, maintain or enhance water and air quality, and promote plant and animal health. Soil quality assessment is an essential issue in soil management for agriculture and natural resource protection. This study was conducted to detect the effects of four crop rotation systems (rice-rice-rice, soya-rice-rice, fallow-rice and pea-soya-rice) on soil quality indicators (soil moisture, porosity, bulk density, water-filled pore space, pH, extractable P, CEC, OC, OM, microbial respiration, active carbon) in paddy soils of Verona area, Northern Italy. Four adjacent plots which managed almost similarly, over five years were selected. Surface soil samples were collected from each four rotation systems in four times, during growing season. Each soil sample was a composite of sub-samples taken from 3 points within 350 m2 of agricultural land. A total of 48 samples were air-dried and passed through 2mm sieve, for some chemical, biological, and physical measurements. Statistical analysis was done using SPSS. Statistical results revealed that frequency distribution of most data was normal. The lowest CV% was related to pH. Analysis of variance (ANOVA) and comparison test showed that there are significant differences in soil quality indicators among crop rotation systems and sampling times. Results of multivariable regression analysis revealed that soil respiration had positively correlation coefficient with soil organic matter, soil moisture and cation exchange capacity. Overall results indicated that the rice rotation with legumes such as bean and soybean improved soil quality over a long time in comparison to rice-fallow rotation, and this is reflected in rice yield. Keywords: Soil quality, Crop Rotation System, Paddy Soils, Italy

  2. Conceptual design of soil venting systems

    SciTech Connect

    DePaoli, D.W.; Wilson, J.H.; Thomas, C.O.

    1996-05-01

    A method for economically based conceptual design of soil venting systems is described. The objective of this method is to provide a means of estimating the cost and schedule of site cleanup for the purposes of technology selection and for focusing detailed system design. Idealized treatments of contaminant volatilization and flow of gas in the soil are employed to obtain estimates of transient off-gas concentration and the vacuum required at the extraction vents for a given set of site and system design conditions. Capital and operating costs of blowers and emissions control devices are estimated using standard techniques, allowing comparison of the required processing cost for cleanup under various design strategies. The utility of this technique is illustrated for an example case of a 95,000-L (25,000-gal) JP-4 jet fuel spill. The results for this test case indicate that emissions control predictably increases cleanup cost, with carbon adsorption being more costly than catalytic oxidation. This treatment predicts that an optimum flow rate and system size exist for each design strategy at a particular site.

  3. Analysis of grounding systems in soils with hemispherical layering

    SciTech Connect

    Ma, J.; Dawalibi, F.P. ); Daily, W.K. )

    1993-10-01

    A theoretical model for the analysis of grounding systems located inside or near hemispherical soil heterogeneities is presented for the first time. Exact closed-form analytical expressions for the earth potential calculations due to current sources in different regions of this soil structure have been obtained. Numerical results are presented for different grounding systems and for different types of hemispherical soil volumes. The results clearly show that these finite hemispherical soil heterogeneities have a significant influence on the performance of grounding systems. The results obtained are in agreement with well known simple case results and converge asymptotically to the uniform soil case.

  4. History of Soil Survey and Evolution of the Brazilian Soil Classification System - SiBCS

    NASA Astrophysics Data System (ADS)

    Cunha dos Anjos, Lúcia Helena; Csekö Nolasco de Carvalho, Claudia; Homem Antunes, Mauro Antonio; Muggler, Cristine Carole

    2014-05-01

    In Brazil soil surveys started around 1940 and the first map with soil information of São Paulo State was published in 1943. The Committee of Soils of the National Service for Agronomic Research was created in 1947 by the Agriculture Ministry and became an historical landmark for soil survey in Brazil. In 1953, the National Program of soil survey was approved and the first soil map and report of Rio de Janeiro State was released in 1958, followed by São Paulo State in 1960. This is also the origin of Embrapa Soil Research institution. Other milestones were the soil surveys published by the Agronomic Institute of Campinas (IAC) and the natural resources studies published within the RADAMBRASIL Project, initially planned for the Amazon region and later covering the whole country. Many soil studies followed and a comprehensive knowledge of tropical soils was achieved resulting in successful technologies for agriculture production, in lands considered by many as of "low fertility and acid soils with limited or no agricultural potential". However, detailed soil surveys are still lacking; only 5% of the country soils are mapped in 1:25.000 scales, and 15-20% in 1:100.000. In the first soil survey reports of Rio de Janeiro (1958) and São Paulo (1960), soil classes were defined according to Baldwin, Kellog & Thorp (Yearbook of Agriculture for 1938), and Thorp & Smith (Soil Science, 67, 1949) publications. It was already clear that the existing classification systems were not adequate to represent the highly weathered tropical soils of the large old landscapes in the cerrado (savanna like) region, or the soils formed on recent hydromorphic conditions at the Amazon Basin and Pantanal region. A national classification system to embody the country's large territory and environmental variation from tropical to subtropical and semiarid conditions, as well as the diversity of soil forming processes in old and new landscapes had to be developed. In 1964, the first attempt of a

  5. Midwest cropping system effects on soil properties and on a soil quality index

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cropping systems may improve or decrease soil quality, depending on the specific crop rotation, nutrient amendments, and tillage practices employed. We evaluated soil properties from six cropping systems in the Wisconsin Integrated Cropping Systems Trial (WICST) after 18 years of continuous treatmen...

  6. Thermal Conductivity Prediction of Soil in Complex Plant Soil System using Artificial Neural Networks

    NASA Astrophysics Data System (ADS)

    Wardani, A. K.; Purqon, A.

    2016-08-01

    Thermal conductivity is one of thermal properties of soil in seed germination and plants growth. Different soil types have different thermal conductivity. One of soft-computing promising method to predict thermal conductivity of soil types is Artificial Neural Network (ANN). In this study, we estimate the thermal conductivity of soil prediction in a soil-plant complex systems using ANN. With a feed-forward multilayer trained with back-propagation with 4, 10 and 1 on the input, hidden and output layers respectively. Our input are heating time, temperature and thermal resistance with thermal conductivity of soil as a target. ANN prediction demonstrates a good agreement with Mean Squared Error-testing (MSEte) of 9.56 x 10-7 for soils with green beans and those of bare soils is 7.00 × 10-7 respectively Green beans grow only on black-clay soil with a thermal conductivity of 0.7 W/m K with a sufficient water content. Our results demonstrate that temperature, moisture content, colour, texture and structure of soil are greatly affect to the thermal conductivity of soil in seed germination and plant growth. In future, it is potentially applied to estimate more complex compositions of plant-soil systems.

  7. Soil heterotrophic respiration responses to meteorology, soil types and cropping systems in a temperate agricultural watershed.

    NASA Astrophysics Data System (ADS)

    Buysse, Pauline; Viaud, Valérie; Fléchard, Chris

    2015-04-01

    Within the context of Climate Change, a better understanding of soil organic matter dynamics is of considerable importance in agro-ecosystems, due to their large mitigation potential. This study aims at better understanding the process of soil heterotrophic respiration at the annual scale and at the watershed scale, with these temporal and spatial scales allowing an integration of the most important drivers: cropping systems and management, topography, soil types, soil organic carbon content and meteorological conditions. Twenty-four soil CO2 flux measurement sites - comprising three PVC collars each - were spread over the Naizin-Kervidy catchment (ORE AgrHys, 4.9 km², W. France) in March 2014. These sites were selected in order to represent most of the diversity in drainage classes, soil types and cropping systems. Soil CO2 flux measurements were performed about every ten to fifteen days at each site, starting from 20 March 2014, using the dynamic closed chamber system Li-COR 8100. Soil temperature and soil moisture content down to 5 cm depth were measured simultaneously. An empirical model taking the influence of meteorological drivers (soil temperature and soil water content) on soil CO2 fluxes was applied to each site and the different responses were analyzed with regard to site characteristics (topography, soil organic carbon content, soil microbial biomass, crop type, crop management,…) in order to determine the most important driving variables of soil heterotrophic respiration. The modeling objective is then to scale the fluxes measured at all sites up to the full watershed scale.

  8. Soil management systems to improve water availability for plants

    NASA Astrophysics Data System (ADS)

    Klik, A.; Rosner, J.

    2009-04-01

    Due to climate change it is expected that the air temperature will increase and the amount as well as the variability of rainfall will change drastically within this century. Higher temperatures and fewer rainy days with more extreme events will increase the risk of surface runoff and erosion. This will lead to reduced soil water storage and therefore to a lower water use efficiency of plants. Soil and land management systems need to be applied and adapted to improve the amount of water stored in the soil and to ensure crop productivity functions of soils under changing climatic conditions. In a 14-yr. long field experiment, the effects of three soil management systems have been studied at three sites in Austria with respect to surface runoff, soil erosion, losses of nutrients and pesticides. Eight years after beginning of the project soil samples have been taken from different depth throughout the root zone to investigate the effects on soil properties. The results show that soil management systems with reduced tillage intensity are able to improve infiltration and soil water storage. More soil water enables plant development during longer dry periods and decreases amounts of irrigation. Overall, the higher water retention in the landscape improves the regional water balance and reduces environmental problems like soil erosion and nutrient and pesticide losses

  9. Soil properties mapping with the DIGISOIL multi-sensor system

    NASA Astrophysics Data System (ADS)

    Grandjean, G.

    2012-04-01

    The multidisciplinary DIGISOIL project aimed to integrate and improve in situ and proximal measurement technologies for the assessment of soil properties and soil degradation indicators, going from the sensing technologies to their integration and their application in (digital) soil mapping (DSM). In order to assess and prevent soil degradation and to benefit from the different ecological, economical and historical functions of the soil in a sustainable way, high resolution and quantitative maps of soil properties are needed. The core objective of the project is to explore and exploit new capabilities of advanced geophysical technologies for answering this societal demand. To this aim, DIGISOIL addresses four issues covering technological, soil science and economic aspects: (i) the validation of geophysical (in situ, proximal and airborne) technologies and integrated pedo-geophysical inversion techniques (mechanistic data fusion) (ii) the relation between the geophysical parameters and the soil properties, (iii) the integration of the derived soil properties for mapping soil functions and soil threats, (iv) the pre-evaluation, standardisation and sub-industrialization of the proposed methodologies, including technical and economical studies related to the societal demand. With respect to these issues, the DIGISOIL project allows to develop, test and validate the most relevant geophysical technologies for mapping soil properties. The system was tested on different field tests, and validated the proposed technologies and solutions for each of the identified methods: geoelectric, GPR, EMI, seismics, magnetic and hyperspectral. After data acquisition systems, sensor geometry, and advanced data processing techniques have been developed and validated, we present now the solutions for going from geophysical data to soil properties maps. For two test sites, located respectively in Luxembourg (LU) and Mugello (IT) a set of soil properties maps have been produced. They give

  10. Plant-uptake of uranium: Hydroponic and soil system studies

    USGS Publications Warehouse

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

    2001-01-01

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

  11. Ecological niches of major soil types in Russia: Geographical aspects of the new Russian soil classification system

    NASA Astrophysics Data System (ADS)

    Tonkonogov, V. D.; Lebedeva, I. I.; Gerasimova, M. I.; Khokhlov, S. F.

    2009-09-01

    The factors of soil formation are not directly taken into account in the new profile-genetic Russian soil classification system; they are not reflected in the names and diagnostics of the soils. At the same time, as well as in many other modern soil classification systems, including the American Soil Taxonomy and the WRB system, the choice of the diagnostic criteria, the establishment of the relationships between them, and the setting of the quantitative boundaries between the soil taxa are based on our perception of soil geneses with due account for the factors of soil formation. In contrast to the ecological-genetic soil classification system of 1977, information on the factors of soil formation in the new system is encoded in the properties of the soil horizons. In some cases, this is insufficient for the definite geographic localization of soils and complicates the practical application of the new classification system. In this context, information on the ecological niches of soil types was included in the field manual on soil correlation-an abridged version of the soil classification system published in 2008—in the form of special tables developed for native and agrogenic soils. The analysis of these tables made it possible to outline certain geographic regularities in the distribution of soil types belonging to the trunk of postlithogenic soils.

  12. Spatial Variation of Soil Type and Soil Moisture in the Regional Atmospheric Modeling System

    SciTech Connect

    Buckley, R.

    2001-06-27

    Soil characteristics (texture and moisture) are typically assumed to be initially constant when performing simulations with the Regional Atmospheric Modeling System (RAMS). Soil texture is spatially homogeneous and time-independent, while soil moisture is often spatially homogeneous initially, but time-dependent. This report discusses the conversion of a global data set of Food and Agriculture Organization (FAO) soil types to RAMS soil texture and the subsequent modifications required in RAMS to ingest this information. Spatial variations in initial soil moisture obtained from the National Center for Environmental Predictions (NCEP) large-scale models are also introduced. Comparisons involving simulations over the southeastern United States for two different time periods, one during warmer, more humid summer conditions, and one during cooler, dryer winter conditions, reveals differences in surface conditions related to increases or decreases in near-surface atmospheric moisture con tent as a result of different soil properties. Three separate simulation types were considered. The base case assumed spatially homogeneous soil texture and initial soil moisture. The second case assumed variable soil texture and constant initial soil moisture, while the third case allowed for both variable soil texture and initial soil moisture. The simulation domain was further divided into four geographically distinct regions. It is concluded there is a more dramatic impact on thermodynamic variables (surface temperature and dewpoint) than on surface winds, and a more pronounced variability in results during the summer period. While no obvious trends in surface winds or dewpoint temperature were found relative to observations covering all regions and times, improvement in surface temperatures in most regions and time periods was generally seen with the incorporation of variable soil texture and initial soil moisture.

  13. An integrated GIS application system for soil moisture data assimilation

    NASA Astrophysics Data System (ADS)

    Wang, Di; Shen, Runping; Huang, Xiaolong; Shi, Chunxiang

    2014-11-01

    The gaps in knowledge and existing challenges in precisely describing the land surface process make it critical to represent the massive soil moisture data visually and mine the data for further research.This article introduces a comprehensive soil moisture assimilation data analysis system, which is instructed by tools of C#, IDL, ArcSDE, Visual Studio 2008 and SQL Server 2005. The system provides integrated service, management of efficient graphics visualization and analysis of land surface data assimilation. The system is not only able to improve the efficiency of data assimilation management, but also comprehensively integrate the data processing and analysis tools into GIS development environment. So analyzing the soil moisture assimilation data and accomplishing GIS spatial analysis can be realized in the same system. This system provides basic GIS map functions, massive data process and soil moisture products analysis etc. Besides,it takes full advantage of a spatial data engine called ArcSDE to effeciently manage, retrieve and store all kinds of data. In the system, characteristics of temporal and spatial pattern of soil moiture will be plotted. By analyzing the soil moisture impact factors, it is possible to acquire the correlation coefficients between soil moisture value and its every single impact factor. Daily and monthly comparative analysis of soil moisture products among observations, simulation results and assimilations can be made in this system to display the different trends of these products. Furthermore, soil moisture map production function is realized for business application.

  14. Management of soil systems for the disposal of industrial wastes

    SciTech Connect

    Corey, J C

    1981-01-01

    Research continues to provide improved information about the toxicity of materials, their transport in soil, and the kinetics of detoxification that is most useful in evaluating alternative approaches for safely managing industrial wastes. The placement of industrial wastes into soil systems is a satisfactory management approach if the material is nontoxic, if the soil has the capability of detoxifying the material, or if the soil prevents the material from entering the biosphere. Examples from the literature of successful applications of industrial wastes to soil are discussed.

  15. System for the removal of contaminant soil-gas vapors

    DOEpatents

    Weidner, Jerry R.; Downs, Wayne C.; Kaser, Timothy G.; Hall, H. James

    1997-01-01

    A system extracts contaminated vapors from soil or other subsurface regions by using changes in barometric pressure to operate sensitive check valves that control air entry and removal from wells in the ground. The system creates an efficient subterranean flow of air through a contaminated soil plume and causes final extraction of the contaminants from the soil to ambient air above ground without any external energy sources.

  16. System for the removal of contaminant soil-gas vapors

    DOEpatents

    Weidner, J.R.; Downs, W.C.; Kaser, T.G.; Hall, H.J.

    1997-12-16

    A system extracts contaminated vapors from soil or other subsurface regions by using changes in barometric pressure to operate sensitive check valves that control air entry and removal from wells in the ground. The system creates an efficient subterranean flow of air through a contaminated soil plume and causes final extraction of the contaminants from the soil to ambient air above ground without any external energy sources. 4 figs.

  17. Soil Biological Parameters Influenced By Cocoa Management Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cropping systems have a profound influence on the soil micro-fauna and they are responsible for nutrient cycling, and add stability to the soil. At Tarapoto, Peru, two field experiments were established on acidic medium fertility Alfisol to assess the influence of management systems on cacao rhizosp...

  18. Predicting the Spectral Effects of Soils on Concentrating Photovoltaic Systems

    DOE PAGES

    Burton, Patrick D.; King, Bruce Hardison; Riley, Daniel M.

    2014-12-15

    The soiling losses on high concentrating photovoltaic (HCPV) systems may be influenced by the spectral properties of accumulated soil. We predicted the response of an isotype cell to changes in spectral content and reduction in transmission due to soiling using measured UV/vis transmittance through soil films. Artificial soil test blends deposited on glass coupons were used to supply the transmission data, which was then used to calculate the effect on model spectra. Moreover, the wavelength transparency of the test soil was varied by incorporating red and yellow mineral pigments into graded sand. The more spectrally responsive (yellow) soils were predictedmore » to alter the current balance between the top and middle subcells throughout a range of air masses corresponding to daily and seasonal variation.« less

  19. Predicting the Spectral Effects of Soils on Concentrating Photovoltaic Systems

    SciTech Connect

    Burton, Patrick D.; King, Bruce Hardison; Riley, Daniel M.

    2014-12-15

    The soiling losses on high concentrating photovoltaic (HCPV) systems may be influenced by the spectral properties of accumulated soil. We predicted the response of an isotype cell to changes in spectral content and reduction in transmission due to soiling using measured UV/vis transmittance through soil films. Artificial soil test blends deposited on glass coupons were used to supply the transmission data, which was then used to calculate the effect on model spectra. Moreover, the wavelength transparency of the test soil was varied by incorporating red and yellow mineral pigments into graded sand. The more spectrally responsive (yellow) soils were predicted to alter the current balance between the top and middle subcells throughout a range of air masses corresponding to daily and seasonal variation.

  20. Acidity field of soils as ion-exchange systems and the diagnostics of genetic soil horizons

    NASA Astrophysics Data System (ADS)

    Kokotov, Yu. A.; Sukhacheva, E. Yu.; Aparin, B. F.

    2014-12-01

    For the comprehensive description of the acidity of a two-phase ion-exchange system, we should analyze two curves of the ionite titration by a strong base in water and salt solutions and find the quantitative relationships between the corresponding pH characteristics. An idea of the three-dimensional field of acidity of ion-exchange systems (the phase space of the soil acidity characteristics) and its three two-dimensional projections is suggested. For soils, three interrelated characteristics—the pH values of the salt and water extracts and the degree of base saturation—can serve as spatial coordinates for the acidity field. Representation of factual data in this field makes it possible to compare and analyze the acidity characteristics of different soils and soil horizons and to determine their specific features. Differentiation of the field into separate volumes allows one to present the data in a discrete form. We have studied the distribution patterns of the groups of soil horizons from Leningrad oblast and other regions of northwestern Russia in the acidity field. The studied samples are grouped in different partially overlapping areas of the projections of the acidity field. The results of this grouping attest to the correctness of the modern classification of Russian soils. A notion of the characteristic soil area in the acidity field is suggested; it can be applied to all the soils with a leaching soil water regime.

  1. Soil Management Plan For The Potable Water System Upgrades Project

    SciTech Connect

    Field, S. M.

    2007-04-01

    This plan describes and applies to the handling and management of soils excavated in support of the Y-12 Potable Water Systems Upgrades (PWSU) Project. The plan is specific to the PWSU Project and is intended as a working document that provides guidance consistent with the 'Soil Management Plan for the Oak Ridge Y-12 National Security Complex' (Y/SUB/92-28B99923C-Y05) and the 'Record of Decision for Phase II Interim Remedial Actions for Contaminated Soils and Scrapyard in Upper East Fork Popular Creek, Oak Ridge, Tennessee' (DOE/OR/01-2229&D2). The purpose of this plan is to prevent and/or limit the spread of contamination when moving soil within the Y-12 complex. The major feature of the soil management plan is the decision tree. The intent of the decision tree is to provide step-by-step guidance for the handling and management of soil from excavation of soil through final disposition. The decision tree provides a framework of decisions and actions to facilitate Y-12 or subcontractor decisions on the reuse of excavated soil on site and whether excavated soil can be reused on site or managed as waste. Soil characterization results from soil sampling in support of the project are also presented.

  2. Soil consumption: An innovative system for better planning and managing soil in urban planning context

    NASA Astrophysics Data System (ADS)

    Basile, Angelo; Bonfante, Antonello; Langella, Giuliano; Minieri, Luciana; De Michele, Carlo; D'Antonio, Amedeo; Manna, Piero; Terribile, Fabio

    2015-04-01

    Soil is a key natural resource and most crucial ecosystem services and the most important environmental benefits to humankind and the environment depend by its properties. However, soil is a delicate resource. Urbanization is the most impactful use of soils because it can cancel all its ecosystem functions and ends forever its life cycle since soil is removed completely and/or sealed with a cement/bitumen layer. The absence of an adequate soil culture led common urban planning to do not consider the reality of soil as living multifunctional system. In such framework, this work - performed under the project LIFE + SOILCONSWEB - aims to illustrate a different approach for soil management in spatial planning using a Spatial Decision Support System operating through the web (w-SDSS) to evaluate soil consumption. The system - already operating in an area of Southern Italy (Telese valley, 20,000 ha) - allows - in real time - to provide answers such as (i) the use of land (type and size) on different dates, (ii) mapping and statistics on the sprawl at the municipality scale, (iii) detailed mapping of land fragmentation (and statistical fragmentation) on different dates, (iv) quantification of loss of ecosystem services after potential new urbanization.

  3. Electrokinetic electrode system for extraction of soil contaminants from unsaturated soils

    DOEpatents

    Lindgren, E.R.; Mattson, E.D.

    1995-07-25

    An electrokinetic electrode assembly is described for use in extraction of soil contaminants from unsaturated soil in situ. The assembly includes a housing for retaining a liquid comprising an electrolyte solution, pure water, and soil water, the housing being in part of porous material capable of holding a vacuum. An electrode is mounted in the housing. The housing is provided with a vacuum orifice for effecting a vacuum within the housing selectively to control flow of soil water through the housing into the chamber and to control outflow of the liquid from the chamber. The assembly further includes conduit means for removing the liquid from the housing and returning the electrolyte solution to the housing, and a conduit for admitting pure water to the housing. An electrode system and method are also revealed for extraction of soil contaminants. The system and method utilize at least two electrode assemblies as described above. 5 figs.

  4. Electrokinetic electrode system for extraction of soil contaminants from unsaturated soils

    DOEpatents

    Lindgren, Eric R.; Mattson, Earl D.

    1995-01-01

    There is presented an electrokinetic electrode assembly for use in extraction of soil contaminants from unsaturated soil in situ. The assembly includes a housing for retaining a liquid comprising an electrolyte solution, pure water, and soil water, the housing being in part of porous material capable of holding a vacuum. An electrode is mounted in the housing. The housing is provided with a vacuum orifice for effecting a vacuum within the housing selectively to control flow of soil water through the housing into the chamber and to control outflow of the liquid from the chamber. The assembly further includes conduit means for removing the liquid from the housing and returning the electrolyte solution to the housing, and a conduit for admitting pure water to the housing. There is further presented an electrode system and method for extraction of soil contaminants, the system and method utilizing at least two electrode assemblies as described above.

  5. [Soil biochemical characteristics in different ecological systems and their relationships with soil respiration and N2O emission].

    PubMed

    Chen, Ling; Fan, Hui; Jiang, Jing-Yan

    2014-08-01

    The biochemical characteristics of soil in different ecological system and their effects on soil respiration (CO2) and nitrous oxide (N2O) emission were investigated by an indoor incubation method. The results showed that the biochemical characteristics of soils in the different ecosystems and CO2 and N2O emissions from different soils greatly varied with each other. In general, the highest abundance of bacteria was found in the orchard soil, the highest abundance of actinomycetes occurred in the meadows and the highest abundance of fungi appeared in the woodlands. The abundance of bacteria or actinomycetes in the bamboo soil was the lowest among all soils, and the orchard soil had the lowest content of fungi. The contents of soil microbial biomass carbon and nitrogen generally followed the order of orchard soil > woodland > cropland. Moreover, cumulative CO2 and N2O emissions from the different soils followed the order of orchard soil > bamboo soil > farmland > woodland > grassland and farmland > orchard > grassland > woodland > bamboo soil, respectively. Correlation analysis indicated that there was positive correlations between the abundance of soil bacteria and the contents of microbial biomass carbon and nitrogen, as well as between the abundance of soil fungi and the soil total nitrogen content (P < 0.05), while the abundance of soil actinomycosis was positively correlated with soil organic carbon and total nitrogen contents (P < 0.01). The soil bacteria, microbial carbon and nitrogen had a significant positive impact on soil respiration (P < 0.05), and soil bacteria, actinomycetes, fungi and ammonium nitrogen had the same impact on N2O emissions (P < 0.05). Stepwise regression analysis suggested that soil respiration could be quantitatively determined by a linear combination of soil bacteria and soil pH, while N2O emission was mainly dependent on the values of soil bacteria and ammonium nitrogen.

  6. Tree root systems competing for soil moisture in a 3D soil-plant model

    NASA Astrophysics Data System (ADS)

    Manoli, Gabriele; Bonetti, Sara; Domec, Jean-Christophe; Putti, Mario; Katul, Gabriel; Marani, Marco

    2014-04-01

    Competition for water among multiple tree rooting systems is investigated using a soil-plant model that accounts for soil moisture dynamics and root water uptake (RWU), whole plant transpiration, and leaf-level photosynthesis. The model is based on a numerical solution to the 3D Richards equation modified to account for a 3D RWU, trunk xylem, and stomatal conductances. The stomatal conductance is determined by combining a conventional biochemical demand formulation for photosynthesis with an optimization hypothesis that selects stomatal aperture so as to maximize carbon gain for a given water loss. Model results compare well with measurements of soil moisture throughout the rooting zone, of total sap flow in the trunk xylem, as well as of leaf water potential collected in a Loblolly pine forest. The model is then used to diagnose plant responses to water stress in the presence of competing rooting systems. Unsurprisingly, the overlap between rooting zones is shown to enhance soil drying. However, the 3D spatial model yielded transpiration-bulk root-zone soil moisture relations that do not deviate appreciably from their proto-typical form commonly assumed in lumped eco-hydrological models. The increased overlap among rooting systems primarily alters the timing at which the point of incipient soil moisture stress is reached by the entire soil-plant system.

  7. Evaluation of a soil slurry reactor system for treating soil contaminated with munitions compounds

    SciTech Connect

    Boopathy, R.; Manning, J.; Montemagno, C.; Kulpa, C.F.

    1994-05-01

    Two 0.5-L semicontinuous soil slurry reactors were operated for seven months to evaluate the performance of the slurry reactor system in bioremediating soil contaminated with munitions compounds. Nitrogen and carbon were supplemented. The soil slurry was mixed continuously and aerated 10 min/day. Ten percent of the contaminated soil was replaced every week. The 2,4,6-trinitrotoluene (TNT) concentration in soil began to drop after 15 days of treatment, falling to less than 0.5 mg/kg from 7800 mg/kg. Total plate counts in both reactors indicated that the bacterial population was maintained, with an average plate count of about 10{sup 8} CFU/mL. The soil slurry was slightly acidic. In addition to TNT, the slurry reactor also removed the other munitions compounds trinitrobenzene (TNB), 2,4-dinitrotoluene (2,4-DNT), RDX, and HMX. Radiolabeling studies on the reactor biomass showed that 23% of [{sup C}14]TNT was mineralized, while 27% was used as biomass and 8% was adsorbed on to the soil. The rest of the [{sup 14}C]TNT was accounted for as TNT metabolites. Increasing the frequency of soil replacement from once to two or three times weekly did not affect the TNT removal rates. However, the slurry system showed signs of stress, with highly acidic conditions and low oxygen uptake rates.

  8. DEMONSTRATION BULLETIN: SOIL/SEDIMENT WASHING SYSTEM BERGMANN USA

    EPA Science Inventory

    The Bergmann USA Soil/Sediment Washing System is a waste minimization technique designed to separate or "partition" soils and sediments by grain size and density. In this water-based volume reduction process, hazardous contaminants are concentrated into a small residual portion...

  9. In-situ remediation system for groundwater and soils

    DOEpatents

    Corey, J.C.; Kaback, D.S.; Looney, B.B.

    1991-01-01

    The present invention relates to a system for in-situ remediation of contaminated groundwater and soil. In particular the present invention relates to stabilizing toxic metals in groundwater and soil. The United States Government has rights in this invention pursuant to Contract No. DE-AC09-89SR18035 between the US Department of Energy and Westinghouse Savannah River Company.

  10. Soil water availability as controlling factor for actual evapotranspiration in urban soil-vegetation-systems

    NASA Astrophysics Data System (ADS)

    Thomsen, Simon; Reisdorff, Christoph; Gröngröft, Alexander; Jensen, Kai; Eschenbach, Annette

    2015-04-01

    The City of Hamburg is characterized by a large number of greens, parks and roadside trees: 600.000 trees cover about 14% of the city area, and moreover, 245.000 roadside trees can be found here. Urban vegetation is generally known to positively contribute to the urban micro-climate via cooling by evapotranspiration (ET). The water for ET is predominantly stored in the urban soils. Hence, the actual evapotranspiration (ETa) is - beside atmospheric drivers - determined by soil water availability at the soil surface and in the rooting zones of the respective vegetation. The overall aim of this study is to characterize soil water availability as a regulative factor for ETa in urban soil-vegetation systems. The specific questions addressed are: i) What is the spatio-temporal variation in soil water availability at the study sites? ii) Which soil depths are predominantly used for water uptake by the vegetation forms investigated? and iii) Which are the threshold values of soil water tension and soil water content (Θ), respectively, that limit ETa under dry conditions on both grass-dominated and tree-dominated sites? Three study areas were established in the urban region of Hamburg, Germany. We selected areas featuring both single tree stands and grass-dominated sites, both representing typical vegetation forms in Hamburg. The areas are characterized by relatively dry soil conditions. However, they differ in regard to soil water availability. At each area we selected one site dominated by Common Oak (Quercus ruber L.) with ages from 40 to 120 years, and paired each oak tree site with a neighboring grass-dominated site. All field measurements were performed during the years 2013 and 2014. At each site, we continuously measured soil water tension and Θ up to 160 cm depth, and xylem sap flux of each of three oak trees per site in a 15 min-resolution. Furthermore, we measured soil hydraulic properties as pF-curve, saturated and unsaturated conductivity at all sites

  11. Soil 13C Dynamics in Aggregates Across a Soil Profile Under an Established Miscanthus System

    NASA Astrophysics Data System (ADS)

    Dondini, M.; Groenigen, K. J.; Jones, M.

    2008-12-01

    Soils are the largest pool of terrestrial organic carbon (C), containing nearly three times the amount of C as the atmosphere. Environmental changes that affect soil C dynamics could slow down the rise in atmospheric CO2 and associated warming by promoting soil C storage. Our capacity to predict the consequences for global change therefore depends on a better understanding of the distribution and controls of soil organic C and how vegetation change may affect SOC distributions. One land cover change of particular interest involves the establishment of bio energy crop stands. The full mitigation potential of bio energy crops cannot be considered without taking into account their effect on soil C dynamics. Miscanthus, a perennial C4 grass from Eastern Asia, has recently received considerable interest as a bio-energy crop. For that reason, we analyzed the C content and the 13C signatures across the soil profile in a 14 year old Miscanthus system, established on former arable land. We combined SOM fractionation techniques by size and density, allowing us to investigate small shifts in soil C stores that would be significant in the long term, but that might not be detected by conventional methodologies. The 13C signal of the various SOM fractions allowed us to distinguish between Miscanthus-derived vs. native soil organic C. Soils under Miscanthus contained 796 g C/m2 in the 0-15 cm layer, and 1233g C/m2 in the 15- 30 cm layer. These values are significantly higher than soil C contents in the arable land. Macroaggregates under Miscanthus contain more than twice as much C compared to arable land, showing a decrease in soil C content with decreasing aggregate size. These differences are largely caused by soil C storage in the microaggregate within macroaggregates fraction. Under Miscanthus, this fraction contains 440 g C/m2 and 488 g C/m2 at 0-15 cm and 15-30 cm respectively, while under the arable land it has mean values of 174 g C/m2 and 353 g C/m2. Our data suggest a

  12. A microwave systems approach to measuring root zone soil moisture

    NASA Technical Reports Server (NTRS)

    Newton, R. W.; Paris, J. F.; Clark, B. V.

    1983-01-01

    Computer microwave satellite simulation models were developed and the program was used to test the ability of a coarse resolution passive microwave sensor to measure soil moisture over large areas, and to evaluate the effect of heterogeneous ground covers with the resolution cell on the accuracy of the soil moisture estimate. The use of realistic scenes containing only 10% to 15% bare soil and significant vegetation made it possible to observe a 60% K decrease in brightness temperature from a 5% soil moisture to a 35% soil moisture at a 21 cm microwave wavelength, providing a 1.5 K to 2 K per percent soil moisture sensitivity to soil moisture. It was shown that resolution does not affect the basic ability to measure soil moisture with a microwave radiometer system. Experimental microwave and ground field data were acquired for developing and testing a root zone soil moisture prediction algorithm. The experimental measurements demonstrated that the depth of penetration at a 21 cm microwave wavelength is not greater than 5 cm.

  13. The Soil Degradation Subsystem of the Hungarian Environmental Information System

    NASA Astrophysics Data System (ADS)

    Szabó, József; Pirkó, Béla; Szabóné Kele, Gabriella; Dombos, Miklós; László, Péter; Koós, Sándor; Bakacsi, Zsófia; Laborczi, Annamária; Pásztor, László

    2013-04-01

    Regular data collection on the state of agricultural soils has not been in operation in Hungary for more than two decades. In the meantime, mainly thanks to the Hungarian Soil Strategy and the planned Soil Framework Directive, the demand for the information on state of Hungarian soils and the follow up of the harmful changes in their conditions and functioning has greatly increased. In 2010 the establishment of a new national soil monitoring system was supported by the Environment and Energy Operational Programme for Informatics Development. The aim of the project was to collect, manage, analyse and publish soil data related to the state of soils and the environmental stresses attributed to the pressures due to agriculture; setting up an appropriate information system in order to fulfil the directives of the Thematic Strategy for Soil Protection. Further objective was the web-based publication of soil data as well as information to support the related public service mission and to inform publicity. The developed information system operates as the Soil Degradation Subsystem of the National Environmental Information System being compatible with its other elements. A suitable representative sampling method was elaborated. The representativity is meant for soil associations, landuse, agricultural practices and typical degradation processes. Soil data were collected on county levels led by regional representatives but altogether they are representative for the whole territory of Hungary. During the project, about 700,000 elementary data were generated, close to 2,000 parcels of 285 farms were surveyed resulting more than 9,000 analysis, 7,000 samples and 28,000 pictures. The overall number of the recorded parcels is 4500, with a total area of about 250,000 hectares. The effect of agricultural land use on soils manifests in rapid changes -related to natural processes- in qualitative and quantitative soil parameters. In intensively used agricultural areas, particularly

  14. Influence of Soil Tillage Systems on Soil Respiration and Production on Wheat, Maize and Soybean Crop

    NASA Astrophysics Data System (ADS)

    Moraru, P. I.; Rusu, T.

    2012-04-01

    Soil respiration leads to CO2 emissions from soil to the atmosphere, in significant amounts for the global carbon cycle. Soil capacity to produce CO2 varies depending on soil, season, intensity and quality of agrotechnical tillage, soil water, cultivated plant, fertilizer etc. The data presented in this paper were obtained on argic-stagnic Faeoziom (SRTS, 2003). These areas were was our research, presents a medium multiannual temperature of 8.20C, medium of multiannual rain drowns: 613 mm. The experimental variants chosen were: A. Conventional system (CS): V1-reversible plough (22-25 cm)+rotary grape (8-10 cm); B. Minimum tillage system (MT): V2 - paraplow (18-22 cm) + rotary grape (8-10 cm); V3 - chisel (18-22 cm) + rotary grape (8-10 cm);V4 - rotary grape (10-12 cm); C. No-Tillage systems (NT): V5 - direct sowing. The experimental design was a split-plot design with three replications. In one variant the area of a plot was 300 m2. The experimental variants were studied in the 3 years crop rotation: maize - soy-bean - autumn wheat. To soil respiration under different tillage practices, determinations were made for each crop in four vegetative stages (spring, 5-6 leaves, bean forming, harvest) using ACE Automated Soil CO2 Exchange System. Soil respiration varies throughout the year for all three crops of rotation, with a maximum in late spring (1383 to 2480 mmoli m-2s-1) and another in fall (2141 to 2350 mmoli m-2s-1). The determinations confirm the effect of soil tillage system on soil respiration, the daily average is lower at NT (315-1914 mmoli m-2s-1), followed by MT (318-2395 mmoli m-2s-1) and is higher in the CS (321-2480 mmol m-2s-1). Productions obtained at MT and NT don't have significant differences at wheat and are higher at soybean. The differences in crop yields are recorded at maize and can be a direct consequence of loosening, mineralization and intensive mobilization of soil fertility. Acknowledgments: This work was supported by CNCSIS

  15. Cropping systems modulate the rate and magnitude of soil microbial autotrophic CO2 fixation in soil

    PubMed Central

    Wu, Xiaohong; Ge, Tida; Wang, Wei; Yuan, Hongzhao; Wegner, Carl-Eric; Zhu, Zhenke; Whiteley, Andrew S.; Wu, Jinshui

    2015-01-01

    The effect of different cropping systems on CO2 fixation by soil microorganisms was studied by comparing soils from three exemplary cropping systems after 10 years of agricultural practice. Studied cropping systems included: continuous cropping of paddy rice (rice-rice), rotation of paddy rice and rapeseed (rice-rapeseed), and rotated cropping of rapeseed and corn (rapeseed-corn). Soils from different cropping systems were incubated with continuous 14C-CO2 labeling for 110 days. The CO2-fixing bacterial communities were investigated by analyzing the cbbL gene encoding ribulose-1,5-bisphosphate carboxylase oxygenase (RubisCO). Abundance, diversity and activity of cbbL-carrying bacteria were analyzed by quantitative PCR, cbbL clone libraries and enzyme assays. After 110 days incubation, substantial amounts of 14C-CO2 were incorporated into soil organic carbon (14C-SOC) and microbial biomass carbon (14C-MBC). Rice-rice rotated soil showed stronger incorporation rates when looking at 14C-SOC and 14C-MBC contents. These differences in incorporation rates were also reflected by determined RubisCO activities. 14C-MBC, cbbL gene abundances and RubisCO activity were found to correlate significantly with 14C-SOC, indicating cbbL-carrying bacteria to be key players for CO2 fixation in these soils. The analysis of clone libraries revealed distinct cbbL-carrying bacterial communities for the individual soils analyzed. Most of the identified operational taxonomic units (OTU) were related to Nitrobacter hamburgensis, Methylibium petroleiphilum, Rhodoblastus acidophilus, Bradyrhizobium, Cupriavidus metallidurans, Rubrivivax, Burkholderia, Stappia, and Thiobacillus thiophilus. OTUs related to Rubrivivax gelatinosus were specific for rice-rice soil. OTUs linked to Methylibium petroleiphilum were exclusively found in rice-rapeseed soil. Observed differences could be linked to differences in soil parameters such as SOC. We conclude that the long-term application of cropping systems

  16. Soil organic phosphorus in soils under different land use systems in northeast Germany

    NASA Astrophysics Data System (ADS)

    Slazak, Anna; Freese, Dirk; Hüttl, Reinhard F.

    2010-05-01

    Phosphorus (P) is commonly known as a major plant nutrient, which can act as a limiting factor for plant growth in many ecosystems, including different land use systems. Organic P (Po), transformations in soil are important in determining the overall biological availability of P and additionally Po depletion is caused by land cultivation. It is expected that changes of land use modifies the distribution of soil P among the various P-pools (Ptotal, Plabile, Po), where the Plabile forms are considered to be readily available to plants and Po plays an important role with P nutrition supply for plants. The aim of the study was to measure the different soil P pools under different land use systems. The study was carried out in northeast of Brandenburg in Germany. Different land use systems were studied: i) different in age pine-oak mixed forest stands, ii) silvopastoral land, iii) arable lands. Samples were taken from two mineral soil layers: 0-10 and 10-20 cm. Recently, a variety of analytical methods are available to determine specific Po compounds in soils. The different P forms in the soil were obtained by a sequential P fractionation by using acid and alkaline extractants, which mean that single samples were subjected to increasingly stronger extractants, consequently separating the soil P into fractions based on P solubility. The soil Ptotal for the forest stands ranged from 100 to 183 mg kg -1 whereas Po from 77 to 148 mg kg -1. The Po and Plabile in both soil layers increased significantly with increase of age-old oak trees. The most available-P fraction was Plabile predominate in the oldest pine-oak forest stand, accounting for 29% of soil Ptotal. For the silvopasture and arable study sites the Ptotal content was comparable. However, the highest value of Ptotal was measured in the 30 years old silvopastoral system with 685 mg kg-1 and 728 mg kg-1 at 0-10 cm and 10-20 cm depth, respectively than in arable lands. The results have shown that the 30 years old

  17. Can we manipulate root system architecture to control soil erosion?

    NASA Astrophysics Data System (ADS)

    Ola, A.; Dodd, I. C.; Quinton, J. N.

    2015-03-01

    Soil erosion is a major threat to soil functioning. The use of vegetation to control erosion has long been a topic for research. Much of this research has focused on the above ground properties of plants, demonstrating the important role that canopy structure and cover plays in the reduction of water erosion processes. Less attention has been paid to plant roots. Plant roots are a crucial yet under-researched factor for reducing water erosion through their ability to alter soil properties, such as aggregate stability, hydraulic function and shear strength. However, there have been few attempts to manipulate plant root system properties to reduce soil erosion. Therefore, this review aims to explore the effects that plant roots have on soil erosion and hydrological processes, and how plant root architecture might be manipulated to enhance its erosion control properties. We clearly demonstrate the importance of root system architecture for the control of soil erosion. We also demonstrate that some plant species respond to nutrient enriched patches by increasing lateral root proliferation. The soil response to root proliferation will depend upon its location: at the soil surface dense mats of roots may block soil pores thereby limiting infiltration, enhancing runoff and thus erosion; whereas at depth local increases in shear strength may reinforce soils against structural failure at the shear plane. Additionally, in nutrient deprived regions, root hair development may be stimulated and larger amounts of root exudates released, thereby improving aggregate stability and decreasing erodibility. Utilising nutrient placement at depth may represent a potentially new, easily implemented, management strategy on nutrient poor agricultural land or constructed slopes to control erosion, and further research in this area is needed.

  18. Selenium in Hungary. The rock-soil-human system.

    PubMed

    Gondi, F; Pantó, G; Fehér, J; Bogye, G; Alfthan, G

    1992-12-01

    Selenium (Se) status of Hungarian rock-soil systems has been poorly investigated. The goal of this study was to get general information on the main features of Se geochemistry, and to have a brief look into the human Se status in Hungary, developing an appropriate method for a forthcoming systematic regional investigation. A multistage program was applied: 1. stream sediment sampling; 2. investigation of rock-soil profiles typical in Hungary; and 3. extraction of mobile Se fractions from soils. Human serum samples from apparently healthy blood donors residing in both urban and rural areas were collected from three districts in Hungary. It was concluded that Hungarian rock-soil systems, especially the acid igneous rocks and the widely distributed young sediments (loess and sand formations) with most of the agricultural activity, are low in Se, and the mean serum Se level of the blood samples were also low.

  19. Can we manipulate root system architecture to control soil erosion?

    NASA Astrophysics Data System (ADS)

    Ola, A.; Dodd, I. C.; Quinton, J. N.

    2015-09-01

    Soil erosion is a major threat to soil functioning. The use of vegetation to control erosion has long been a topic for research. Much of this research has focused on the above-ground properties of plants, demonstrating the important role that canopy structure and cover plays in the reduction of water erosion processes. Less attention has been paid to plant roots. Plant roots are a crucial yet under-researched factor for reducing water erosion through their ability to alter soil properties, such as aggregate stability, hydraulic function and shear strength. However, there have been few attempts to specifically manipulate plant root system properties to reduce soil erosion. Therefore, this review aims to explore the effects that plant roots have on soil erosion and hydrological processes, and how plant root architecture might be manipulated to enhance its erosion control properties. We demonstrate the importance of root system architecture for the control of soil erosion. We also show that some plant species respond to nutrient-enriched patches by increasing lateral root proliferation. The erosional response to root proliferation will depend upon its location: at the soil surface dense mats of roots may reduce soil erodibility but block soil pores thereby limiting infiltration, enhancing runoff. Additionally, in nutrient-deprived regions, root hair development may be stimulated and larger amounts of root exudates released, thereby improving aggregate stability and decreasing erodibility. Utilizing nutrient placement at specific depths may represent a potentially new, easily implemented, management strategy on nutrient-poor agricultural land or constructed slopes to control erosion, and further research in this area is needed.

  20. Soils organic C sequestration under poplar and willow agroforestry systems

    NASA Astrophysics Data System (ADS)

    Gunina, Anna; Tariq, Azeem; Lamersdorf, Norbert

    2015-04-01

    Short rotation coppices (SRC) as monocultures or as agroforestry (AF) applications (e.g. alley cropping) are two techniques to implement forest into agricultural practices. Despite afforestation promotes soil carbon (C) accumulation, age and type of the tree stand can affect the C accumulation in different degrees. Here, we studied the impact of afforestation on C accumulation for: i) pure SCR of willow (Salix viminalis x Salix schwerinii) and poplar (Populus nigra x Populus maximowiczii) and ii) AF cropping system with willow. Forest systems have been established within the BEST agroforestry project in Germany. Adjacent agricultural field have been used as a control. Soil samples were collected in 2014, three years after plantation establishment, from three soil depths: 0-3, 3-20, and 20-30 cm. Total organic C, labile C (incubation of 20 g soil during 100 days with measuring of CO2) and aggregate structure were analysed. Additionally, density fractionation of the samples from 0-3 cm was applied to separate particulate organic matter (POM) and mineral fractions. Aggregates and density fractions were analyzed for C content. High input of plant litter as well as root exudates have led to increases of organic C in AF and SRC plots compare to cropland, mainly in the top 0-3 cm. The highest C content was found for willow SRC (18.2 g kg-1 soil), followed by willow-AF (15.6 g kg-1 soil), and poplar SRC (13.7 g kg-1 soil). Carbon content of cropland was 12.5 g kg-1 soil. Absence of ploughing caused increase portion of macroaggregates (>2000 μm) under SRC and AF in all soil layers as well as the highest percentage of C in that aggregate size class (70-80%). In contrast, C in cropland soil was mainly accumulated in small macroaggregates (250-2000 μm). Intensive mineralisation of fresh litter and old POM, taking place during first years of trees development, resulted to similar portions of free POM for willow AF, willow SRC and cropland (8%), and even lower ones for poplar

  1. Explicitly Representing Soil Microbial Processes In Earth System Models

    SciTech Connect

    Wieder, William R.; Allison, Steven D.; Davidson, Eric A.; Georgiou, Katrina; Hararuk, Oleksandra; He, Yujie; Hopkins, Francesca; Luo, Yiqi; Smith, Mathew J.; Sulman, Benjamin; Todd-Brown, Katherine EO; Wang, Ying-Ping; Xia, Jianyang; Xu, Xiaofeng

    2015-10-26

    Microbes influence soil organic matter (SOM) decomposition and the long-term stabilization of carbon (C) in soils. We contend that by revising the representation of microbial processes and their interactions with the physicochemical soil environment, Earth system models (ESMs) may make more realistic global C cycle projections. Explicit representation of microbial processes presents considerable challenges due to the scale at which these processes occur. Thus, applying microbial theory in ESMs requires a framework to link micro-scale process-level understanding and measurements to macro-scale models used to make decadal- to century-long projections. Here, we review the diversity, advantages, and pitfalls of simulating soil biogeochemical cycles using microbial-explicit modeling approaches. We present a roadmap for how to begin building, applying, and evaluating reliable microbial-explicit model formulations that can be applied in ESMs. Drawing from experience with traditional decomposition models we suggest: (1) guidelines for common model parameters and output that can facilitate future model intercomparisons; (2) development of benchmarking and model-data integration frameworks that can be used to effectively guide, inform, and evaluate model parameterizations with data from well-curated repositories; and (3) the application of scaling methods to integrate microbial-explicit soil biogeochemistry modules within ESMs. With contributions across scientific disciplines, we feel this roadmap can advance our fundamental understanding of soil biogeochemical dynamics and more realistically project likely soil C response to environmental change at global scales.

  2. Explicitly representing soil microbial processes in Earth system models

    NASA Astrophysics Data System (ADS)

    Wieder, William R.; Allison, Steven D.; Davidson, Eric A.; Georgiou, Katerina; Hararuk, Oleksandra; He, Yujie; Hopkins, Francesca; Luo, Yiqi; Smith, Matthew J.; Sulman, Benjamin; Todd-Brown, Katherine; Wang, Ying-Ping; Xia, Jianyang; Xu, Xiaofeng

    2015-10-01

    Microbes influence soil organic matter decomposition and the long-term stabilization of carbon (C) in soils. We contend that by revising the representation of microbial processes and their interactions with the physicochemical soil environment, Earth system models (ESMs) will make more realistic global C cycle projections. Explicit representation of microbial processes presents considerable challenges due to the scale at which these processes occur. Thus, applying microbial theory in ESMs requires a framework to link micro-scale process-level understanding and measurements to macro-scale models used to make decadal- to century-long projections. Here we review the diversity, advantages, and pitfalls of simulating soil biogeochemical cycles using microbial-explicit modeling approaches. We present a roadmap for how to begin building, applying, and evaluating reliable microbial-explicit model formulations that can be applied in ESMs. Drawing from experience with traditional decomposition models, we suggest the following: (1) guidelines for common model parameters and output that can facilitate future model intercomparisons; (2) development of benchmarking and model-data integration frameworks that can be used to effectively guide, inform, and evaluate model parameterizations with data from well-curated repositories; and (3) the application of scaling methods to integrate microbial-explicit soil biogeochemistry modules within ESMs. With contributions across scientific disciplines, we feel this roadmap can advance our fundamental understanding of soil biogeochemical dynamics and more realistically project likely soil C response to environmental change at global scales.

  3. Soil organic carbon sequestration and tillage systems in Mediterranean environments

    NASA Astrophysics Data System (ADS)

    Francaviglia, Rosa; Di Bene, Claudia; Marchetti, Alessandro; Farina, Roberta

    2016-04-01

    Soil carbon sequestration is of special interest in Mediterranean areas, where rainfed cropping systems are prevalent, inputs of organic matter to soils are low and mostly rely on crop residues, while losses are high due to climatic and anthropic factors such as intensive and non-conservative farming practices. The adoption of reduced or no tillage systems, characterized by a lower soil disturbance in comparison with conventional tillage, has proved to be positively effective on soil organic carbon (SOC) conservation and other physical and chemical processes, parameters or functions, e.g. erosion, compaction, ion retention and exchange, buffering capacity, water retention and aggregate stability. Moreover, soil biological and biochemical processes are usually improved by the reduction of tillage intensity. The work deals with some results available in the scientific literature, and related to field experiment on arable crops performed in Italy, Greece, Morocco and Spain. Data were organized in a dataset containing the main environmental parameters (altitude, temperature, rainfall), soil tillage system information (conventional, minimum and no-tillage), soil parameters (bulk density, pH, particle size distribution and texture), crop type, rotation, management and length of the experiment in years, initial SOCi and final SOCf stocks. Sampling sites are located between 33° 00' and 43° 32' latitude N, 2-860 m a.s.l., with mean annual temperature and rainfall in the range 10.9-19.6° C and 355-900 mm. SOC data, expressed in t C ha-1, have been evaluated both in terms of Carbon Sequestration Rate, given by [(SOCf-SOCi)/length in years], and as percentage change in comparison with the initial value [(SOCf-SOCi)/SOCi*100]. Data variability due to the different environmental, soil and crop management conditions that influence SOC sequestration and losses will be examined.

  4. Soil organic carbon sequestration and tillage systems in Mediterranean environments

    NASA Astrophysics Data System (ADS)

    Francaviglia, Rosa; Di Bene, Claudia; Marchetti, Alessandro; Farina, Roberta

    2016-04-01

    Soil carbon sequestration is of special interest in Mediterranean areas, where rainfed cropping systems are prevalent, inputs of organic matter to soils are low and mostly rely on crop residues, while losses are high due to climatic and anthropic factors such as intensive and non-conservative farming practices. The adoption of reduced or no tillage systems, characterized by a lower soil disturbance in comparison with conventional tillage, has proved to be positively effective on soil organic carbon (SOC) conservation and other physical and chemical processes, parameters or functions, e.g. erosion, compaction, ion retention and exchange, buffering capacity, water retention and aggregate stability. Moreover, soil biological and biochemical processes are usually improved by the reduction of tillage intensity. The work deals with some results available in the scientific literature, and related to field experiment on arable crops performed in Italy, Greece, Morocco and Spain. Data were organized in a dataset containing the main environmental parameters (altitude, temperature, rainfall), soil tillage system information (conventional, minimum and no-tillage), soil parameters (bulk density, pH, particle size distribution and texture), crop type, rotation, management and length of the experiment in years, initial SOCi and final SOCf stocks. Sampling sites are located between 33° 00' and 43° 32' latitude N, 2-860 m a.s.l., with mean annual temperature and rainfall in the range 10.9-19.6° C and 355-900 mm. SOC data, expressed in t C ha‑1, have been evaluated both in terms of Carbon Sequestration Rate, given by [(SOCf-SOCi)/length in years], and as percentage change in comparison with the initial value [(SOCf-SOCi)/SOCi*100]. Data variability due to the different environmental, soil and crop management conditions that influence SOC sequestration and losses will be examined.

  5. The Soil-Plant-Atmosphere System - Past and Present.

    NASA Astrophysics Data System (ADS)

    Berry, J. A.; Baker, I. T.; Randall, D. A.; Sellers, P. J.

    2012-12-01

    Plants with stomata, roots and a vascular system first appeared on earth about 415 million years ago. This evolutionary innovation helped to set in motion non-linear feedback mechanisms that led to an acceleration of the hydrologic cycle over the continents and an expansion of the climate zones favorable for plant (and animal) life. Skeletal soils that developed long before plants came onto the land would have held water and nutrients in their pore space, yet these resources would have been largely unavailable to primitive, surface-dwelling non-vascular plants due to physical limitations on water transport once the surface layer of soil dries. Plants with roots and a vascular system that could span this dry surface layer could gain increased and prolonged access to the water and nutrients stored in the soil for photosynthesis. Maintenance of the hydraulic connections permitting water to be drawn through the vascular system from deep in the soil to the sites of evaporation in the leaves required a cuticle and physiological regulation of stomata. These anatomical and physiological innovations changed properties of the terrestrial surface (albedo, roughness, a vascular system and control of surface conductance) and set in motion complex interactions of the soil - plant - atmosphere system. We will use coupled physiological and meteorological models to examine some of these interactions.

  6. Soil surface carbon dioxide efflux of bioenergy cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bioenergy cropping systems have been proposed as a way to enhance United States energy security. However, research on greenhouse gas emissions from such systems is needed to ensure environmental sustainability in the field. Since soil aeration properties are dynamic, high-resolution data are needed ...

  7. Water table fluctuations and soil biogeochemistry: An experimental approach using an automated soil column system

    NASA Astrophysics Data System (ADS)

    Rezanezhad, F.; Couture, R.-M.; Kovac, R.; O'Connell, D.; Van Cappellen, P.

    2014-02-01

    Water table fluctuations significantly affect the biological and geochemical functioning of soils. Here, we introduce an automated soil column system in which the water table regime is imposed using a computer-controlled, multi-channel pump connected to a hydrostatic equilibrium reservoir and a water storage reservoir. The potential of this new system is illustrated by comparing results from two columns filled with 45 cm of the same homogenized riparian soil. In one soil column the water table remained constant at -20 cm below the soil surface, while in the other the water table oscillated between the soil surface and the bottom of the column, at a rate of 4.8 cm d-1. The experiment ran for 75 days at room temperature (25 ± 2 °C). Micro-sensors installed at -10 and -30 cm below the soil surface in the stable water table column recorded constant redox potentials on the order of 600 and -200 mV, respectively. In the fluctuating water table column, redox potentials at the same depths oscillated between oxidizing (∼700 mV) and reducing (∼-100 mV) conditions. Pore waters collected periodically and solid-phase analyses on core material obtained at the end of the experiment highlighted striking geochemical differences between the two columns, especially in the time series and depth distributions of Fe, Mn, K, P and S. Soil CO2 emissions derived from headspace gas analysis exhibited periodic variations in the fluctuating water table column, with peak values during water table drawdown. Transient redox conditions caused by the water table fluctuations enhanced microbial oxidation of soil organic matter, resulting in a pronounced depletion of particulate organic carbon in the midsection of the fluctuating water table column. Denaturing Gradient Gel Electrophoresis (DGGE) revealed the onset of differentiation of the bacterial communities in the upper (oxidizing) and lower (reducing) soil sections, although no systematic differences in microbial community structure

  8. Laboratory assessment of factors affecting soil clogging of soil aquifer treatment systems.

    PubMed

    Pavelic, P; Dillon, P J; Mucha, M; Nakai, T; Barry, K E; Bestland, E

    2011-05-01

    In this study the effect of soil type, level of pre-treatment, ponding depth, temperature and sunlight on clogging of soil aquifer treatment (SAT) systems was evaluated over an eight week duration in constant temperature and glasshouse environments. Of the two soil types tested, the more permeable sand media clogged more than the loam, but still retained an order of magnitude higher absolute permeability. A 6- to 8-fold difference in hydraulic loading rates was observed between the four source water types tested (one potable water and three recycled waters), with improved water quality resulting in significantly higher infiltration. Infiltration rates for ponding depths of 30 cm and 50 cm were higher than 10 cm, although for 50 cm clogging rates were higher due to greater compaction of the clogging layer. Overall, physical clogging was more significant than other forms of clogging. Microbial clogging becomes increasingly important when the particulate concentrations in the source waters are reduced through pre-treatment and for finer textured soils due to the higher specific surface area of the media. Clogging by gas binding took place in the glasshouse but not in the lab, and mechanical clogging associated with particle rearrangement was evident in the sand media but not in the loam. These results offer insight into the soil, water quality and operating conditions needed to achieve viable SAT systems.

  9. Transfer model of lead in soil-carrot (Daucus carota L.) system and food safety thresholds in soil.

    PubMed

    Ding, Changfeng; Li, Xiaogang; Zhang, Taolin; Wang, Xingxiang

    2015-09-01

    Reliable empirical models describing lead (Pb) transfer in soil-plant systems are needed to improve soil environmental quality standards. A greenhouse experiment was conducted to develop soil-plant transfer models to predict Pb concentrations in carrot (Daucus carota L.). Soil thresholds for food safety were then derived inversely using the prediction model in view of the maximum allowable limit for Pb in food. The 2 most important soil properties that influenced carrot Pb uptake factor (ratio of Pb concentration in carrot to that in soil) were soil pH and cation exchange capacity (CEC), as revealed by path analysis. Stepwise multiple linear regression models were based on soil properties and the pseudo total (aqua regia) or extractable (0.01 M CaCl2 and 0.005 M diethylenetriamine pentaacetic acid) soil Pb concentrations. Carrot Pb contents were best explained by the pseudo total soil Pb concentrations in combination with soil pH and CEC, with the percentage of variation explained being up to 93%. The derived soil thresholds based on added Pb (total soil Pb with the geogenic background part subtracted) have the advantage of better applicability to soils with high natural background Pb levels. Validation of the thresholds against data from field trials and literature studies indicated that the proposed thresholds are reasonable and reliable.

  10. Construction of a chemical ranking system of soil pollution substances for screening of priority soil contaminants in Korea.

    PubMed

    Jeong, Seung-Woo; An, Youn-Joo

    2012-04-01

    The Korean government recently proposed expanding the number of soil-quality standards to 30 by 2015. The objectives of our study were to construct a reasonable protocol for screening priority soil contaminants for inclusion in the planned soil quality standard expansion. The chemical ranking system of soil pollution substances (CROSS) was first developed to serve as an analytical tool in chemical scoring and ranking of possible soil pollution substances. CROSS incorporates important parameters commonly used in several previous chemical ranking and scoring systems and the new soil pollution parameters. CROSS uses soil-related parameters in its algorithm, including information related to the soil environment, such as soil ecotoxicological data, the soil toxic release inventory (TRI), and soil partitioning coefficients. Soil TRI and monitoring data were incorporated as local specific parameters. In addition, CROSS scores the transportability of chemicals in soil because soil contamination may result in groundwater contamination. Dermal toxicity was used in CROSS only to consider contact with soil. CROSS uses a certainty score to incorporate data uncertainty. CROSS scores the importance of each candidate substance and assigns rankings on the basis of total scores. Cadmium was the most highly ranked. Generally, metals were ranked higher than other substances. Pentachlorophenol, phenol, dieldrin, and methyl tert-butyl ether were ranked the highest among chlorinated compounds, aromatic compounds, pesticides, and others, respectively. The priority substance list generated from CROSS will be used in selecting substances for possible inclusion in the Korean soil quality standard expansion; it will also provide important information for designing a soil-environment management scheme.

  11. In-situ remediation system for groundwater and soils

    DOEpatents

    Corey, J.C.; Kaback, D.S.; Looney, B.B.

    1993-11-23

    A method and system are presented for in-situ remediation of contaminated groundwater and soil where the contaminants, such as toxic metals, are carried in a subsurface plume. The method comprises selection and injection into the soil of a fluid that will cause the contaminants to form stable, non-toxic compounds either directly by combining with the contaminants or indirectly by creating conditions in the soil or changing the conditions of the soil so that the formation of stable, non-toxic compounds between the contaminants and existing substances in the soil are more favorable. In the case of non-toxic metal contaminants, sulfides or sulfates are injected so that metal sulfides or sulfates are formed. Alternatively, an inert gas may be injected to stimulate microorganisms in the soil to produce sulfides which, in turn, react with the metal contaminants. Preferably, two wells are used, one to inject the fluid and one to extract the unused portion of the fluid. The two wells work in combination to create a flow of the fluid across the plume to achieve better, more rapid mixing of the fluid and the contaminants. 4 figures.

  12. In-situ remediation system for groundwater and soils

    DOEpatents

    Corey, John C.; Kaback, Dawn S.; Looney, Brian B.

    1993-01-01

    A method and system for in-situ remediation of contaminated groundwater and soil where the contaminants, such as toxic metals, are carried in a subsurface plume. The method comprises selection and injection into the soil of a fluid that will cause the contaminants to form stable, non-toxic compounds either directly by combining with the contaminants or indirectly by creating conditions in the soil or changing the conditions of the soil so that the formation of stable, non-toxic compounds between the contaminants and existing substances in the soil are more favorable. In the case of non-toxic metal contaminants, sulfides or sulfates are injected so that metal sulfides or sulfates are formed. Alternatively, an inert gas may be injected to stimulate microorganisms in the soil to produce sulfides which, in turn, react with the metal contaminants. Preferably, two wells are used, one to inject the fluid and one to extract the unused portion of the fluid. The two wells work in combination to create a flow of the fluid across the plume to achieve better, more rapid mixing of the fluid and the contaminants.

  13. Simulation of large-scale soil water systems using groundwater data and satellite based soil moisture

    NASA Astrophysics Data System (ADS)

    Kreye, Phillip; Meon, Günter

    2016-04-01

    Complex concepts for the physically correct depiction of dominant processes in the hydrosphere are increasingly at the forefront of hydrological modelling. Many scientific issues in hydrological modelling demand for additional system variables besides a simulation of runoff only, such as groundwater recharge or soil moisture conditions. Models that include soil water simulations are either very simplified or require a high number of parameters. Against this backdrop there is a heightened demand of observations to be used to calibrate the model. A reasonable integration of groundwater data or remote sensing data in calibration procedures as well as the identifiability of physically plausible sets of parameters is subject to research in the field of hydrology. Since this data is often combined with conceptual models, the given interfaces are not suitable for such demands. Furthermore, the application of automated optimisation procedures is generally associated with conceptual models, whose (fast) computing times allow many iterations of the optimisation in an acceptable time frame. One of the main aims of this study is to reduce the discrepancy between scientific and practical applications in the field of hydrological modelling. Therefore, the soil model DYVESOM (DYnamic VEgetation SOil Model) was developed as one of the primary components of the hydrological modelling system PANTA RHEI. DYVESOMs structure provides the required interfaces for the calibrations made at runoff, satellite based soil moisture and groundwater level. The model considers spatial and temporal differentiated feedback of the development of the vegetation on the soil system. In addition, small scale heterogeneities of soil properties (subgrid-variability) are parameterized by variation of van Genuchten parameters depending on distribution functions. Different sets of parameters are operated simultaneously while interacting with each other. The developed soil model is innovative regarding concept

  14. Advanced Assay Systems for Radionuclide Contamination in Soils

    SciTech Connect

    J. R. Giles; L. G. Roybal; M. V. Carpenter; C. P. Oertel; J. A. Roach

    2008-02-01

    Through the support of the Department of Energy (DOE) Office of Environmental Management (EM) Technical Assistance Program, the Idaho National Laboratory (INL) has developed and deployed a suite of systems that rapidly scan, characterize, and analyze surface soil contamination. The INL systems integrate detector systems with data acquisition and synthesis software and with global positioning technology to provide a real-time, user-friendly field deployable turn-key system. INL real-time systems are designed to characterize surface soil contamination using methodologies set forth in the Multi-Agency Radiation Surveys and Site Investigation Manual (MARSSIM). MARSSIM provides guidance for planning, implementing, and evaluating environmental and facility radiological surveys conducted to demonstrate compliance with a dose or risk-based regulation and provides real-time information that is immediately available to field technicians and project management personnel. This paper discusses the history of the development of these systems and describes some of the more recent examples and their applications.

  15. Soil phosphorus dynamics in a humid tropical silvopastoral system

    SciTech Connect

    Cooperband, L.R.

    1992-01-01

    In developing countries of the humid tropics, timber exploitation and agricultural expansion frequently result in deforestation. Extensive land management, coupled with inherently low soil fertility invariably produce declines in agricultural/livestock productivity which eventually lead to land abandonment and further deforestation. Phosphorus is often the major nutrient limiting plant growth in tropical soils. Agroforestry systems have been considered as viable alternatives to current land use practices. Several hypotheses suggest that combining trees with crops or pasture, especially leguminous species will improve soil nutrient cycling, soil structure and soil organic matter. In this experiment Erythrina berteroana (an arboreous legume) was grown in native grass pastures in Costa Rica to determine the effects of tree pruning and cattle grazing on soil P availability. I measured soil P fluxes as well as changes in pasture biomass over an 18-month period. In a separate field experiment, I determined decomposition rates and P release characteristics of Erythrina leaves, pasture grass clippings and cattle dung. Erythrina leaves decomposed faster than both pasture grass and cattle dung. Erythrina and pasture residues released 4-5 times less P than dung. Phosphorus fluxes after tree pruning and grazing were highly dynamic for all treatments. Tree pruning increased labile soil P over time when coupled with grazing. Pasture biomass production was greatest in the grazed tree treatment. Pasture biomass P production and concentration was greatest in the non-grazed treatment. Trees and grazing together tended to increase nutrient (P) turnover which stimulated biomass production. In contrast, trees without grazing promoted nutrient (P) accumulation in pasture biomass.

  16. A sensor array system for monitoring moisture dynamics inunsaturated soil

    SciTech Connect

    Salve, R.; Cook, P.J.

    2007-05-15

    To facilitate investigations of moisture dynamics inunsaturated soil, we have developed a technique to qualitatively monitorpatterns of saturation changes. Field results suggest that this device,the sensor array system (SAS), is suitable for determining changes inrelative wetness along vertical soil profiles. The performance of theseprobes was compared with that of the time domain reflectometry (TDR)technique under controlled and field conditions. Measurements from bothtechniques suggest that by obtaining data at high spatial and temporalresolution, the SAS technique was effective in determining patterns ofsaturation changes along a soil profile. In addition, hardware used inthe SAS technique was significantly cheaper than the TDR system, and thesensor arrays were much easier to install along a soilprofile.

  17. Phosphorus cycling in natural and low input soil/plant systems: the role of soil microorganisms

    NASA Astrophysics Data System (ADS)

    Tamburini, F.; Bünemann, E. K.; Oberson, A.; Bernasconi, S. M.; Frossard, E.

    2011-12-01

    Availability of phosphorus (as orthophosphate, Pi) limits biological production in many terrestrial ecosystems. During the first phase of soil development, weathering of minerals and leaching of Pi are the processes controlling Pi concentrations in the soil solution, while in mature soils, Pi is made available by desorption of mineral Pi and mineralization of organic compounds. In agricultural soils additional Pi is supplied by fertilization, either with mineral P and/or organic inputs (animal manure or plant residues). Soil microorganisms (bacteria and fungi) mediate several processes, which are central to the availability of Pi to plants. They play a role in the initial release of Pi from the mineral phase, and through extracellular phosphatase enzymes, they decompose and mineralize organic compounds, releasing Pi. On the other hand, microbial immobilization and internal turnover of Pi can decrease the soil available Pi pool, competing in this way with plants. Using radio- and stable isotopic approaches, we show evidence from different soil/plant systems which points to the central role of the microbial activity. In the presented case studies, P contained in the soil microbial biomass is a larger pool than available Pi. In a soil chronosequence after deglaciation, stable isotopes of oxygen associated to phosphate showed that even in the youngest soils microbial activity highly impacted the isotopic signature of available Pi. These results suggested that microorganisms were rapidly taking up and cycling Pi, using it to sustain their community. Microbial P turnover time was faster in the young (about 20 days) than in older soils (about 120 days), reflecting a different functioning of the microbial community. Microbial community crashes, caused by drying/rewetting and freezing/thawing cycles, were most likely responsible for microbial P release to the available P pool. In grassland fertilization experiments with mineral NK and NPK amendments, microbial P turnover

  18. Understanding large-extent controls of soil organic carbon storage in relation to soil depth and soil-landscape systems

    NASA Astrophysics Data System (ADS)

    Mulder, Vera L.; Lacoste, Marine; Martin, Manuel P.; Richer-de-Forges, Anne; Arrouays, Dominique

    2015-08-01

    In this work we aimed at developing a conceptual framework in which we improve our understanding of the controlling factors for soil organic carbon (SOC) over vast areas at different depths. We postulated that variability in SOC levels may be better explained by modeling SOC within soil-landscape systems (SLSs). The study was performed in mainland France, and explanatory SOC models were developed for the sampled topsoil (0-30 cm) and subsoil (>30 cm), using both directed and undirected data-mining techniques. With this study we demonstrated that there is a shift in controlling factors both in space and depth which were mainly related to (1) typical SLS characteristics and (2) human-induced changes to SLSs. The controlling factors in relation to depth alter from predominantly biotic to more abiotic with increasing depth. Especially, water availability, soil texture, and physical protection control deeper stored SOC. In SLSs with similar SOC levels, different combinations of physical protection, the input of organic matter, and climatic conditions largely determined the SOC level. The SLS approach provided the means to partition the data into data sets that were having homogenous conditions with respect to this combination of controlling factors. This information may provide important information on the carbon storage and sequestration potential of a soil.

  19. New approach to analyzing soil-building systems

    USGS Publications Warehouse

    Safak, E.

    1998-01-01

    A new method of analyzing seismic response of soil-building systems is introduced. The method is based on the discrete-time formulation of wave propagation in layered media for vertically propagating plane shear waves. Buildings are modeled as an extension of the layered soil media by assuming that each story in the building is another layer. The seismic response is expressed in terms of wave travel times between the layers, and the wave reflection and transmission coefficients at layer interfaces. The calculation of the response is reduced to a pair of simple finite-difference equations for each layer, which are solved recursively starting from the bedrock. Compared with commonly used vibration formulation, the wave propagation formulation provides several advantages, including the ability to incorporate soil layers, simplicity of the calculations, improved accuracy in modeling the mass and damping, and better tools for system identification and damage detection.A new method of analyzing seismic response of soil-building systems is introduced. The method is based on the discrete-time formulation of wave propagation in layered media for vertically propagating plane shear waves. Buildings are modeled as an extension of the layered soil media by assuming that each story in the building is another layer. The seismic response is expressed in terms of wave travel times between the layers, and the wave reflection and transmission coefficients at layer interfaces. The calculation of the response is reduced to a pair of simple finite-difference equations for each layer, which are solved recursively starting from the bedrock. Compared with commonly used vibration formulation, the wave propagation formulation provides several advantages, including the ability to incorporate soil layers, simplicity of the calculations, improved accuracy in modeling the mass and damping, and better tools for system identification and damage detection.

  20. Interactions in Natural Colloid Systems "Biosolids" - Soil and Plant

    NASA Astrophysics Data System (ADS)

    Kalinichenko, Kira V.; Nikovskaya, Galina N.; Ulberg, Zoya R.

    2016-04-01

    The "biosolids" are complex biocolloid system arising in huge amounts (mln tons per year) from biological municipal wastewater treatment. These contain clusters of nanoparticles of heavy metal compounds (in slightly soluble or unsoluble forms, such as phosphates, sulphates, carbonates, hydroxides, and etc.), cells, humic substances and so on, involved in exopolysaccharides (EPS) net matrix. One may consider that biosolids are the natural nanocomposite. Due to the presence of nitrogen, phosphorus, potassium and other macro- and microelements (heavy metals), vitamins, aminoacids, etc., the biosolids are a depot of bioelements for plant nutrition. Thus, it is generally recognized that most rationally to utilize them for land application. For this purpose the biocolloid process was developed in biosolids system by initiation of microbial vital ability followed by the synthesis of EPS, propagation of ecologically important microorganisms, loosening of the structure and weakening of the coagulation contacts between biosolids colloids, but the structure integrity maintaining [1,2]. It was demonstrated that the applying of biosolids with metabolizing microorganisms to soil provided the improving soil structure, namely the increasing of waterstable aggregates content (70% vs. 20%). It occurs due to flocculation ability of biosolids EPS. The experimental modelling of mutual interactions in systems of soils - biosolids (with metabolizing microorganisms) were realized and their colloid and chemical mechanisms were formulated [3]. As it is known, the most harmonious plant growth comes at a prolonged entering of nutrients under the action of plant roots exudates which include pool of organic acids and polysaccharides [4]. Special investigations showed that under the influence of exudates excreted by growing plants, the biosolids microelements can release gradually from immobilized state into environment and are able to absorb by plants. Thus, the biosolids can serve as an active

  1. Microbial Diversity in Soil Treatment Systems for Wastewater

    NASA Astrophysics Data System (ADS)

    Van Cuyk, S.; Spear, J.; Siegrist, R.; Pace, N.

    2002-05-01

    There is an increasing awareness and concern over land based wastewater system performance with respect to the removal of bacteria and virus. The goal of this work is to describe and identify the organismal composition of the microbiota in the applied wastewater effluent, the rich biomat that develops at the infiltrative surface, and in the soil percolate in order to aid in the understanding of bacterial and virus purification in soil treatment systems. The traditional reliance on pure culture techniques to describe microbiota is circumvented by the employment of a molecular approach. Microbial community characterization is underway based on cloning and sequencing of 16S rRNA genes for phylogenetic analyses, to determine the nature and quantity of microbiota that constitute these ecosystems. Knowledge of the organisms naturally present can influence the design and treatment capacity of these widely used land based systems. Laboratory, intermediate and field scale systems are currently under study. Since human pathogens are known to exist in sewage effluents, their removal in wastewater infiltration systems and within the underlying soil are in need of a more fundamental understanding. The relationship between design parameters and environmental conditions, including a microbial characterization, is essential for the prevention of contamination in groundwater sources. Preliminary results indicate the presence of uncultured organisms and phylogenetic kinds that had not been detected in these systems using other methods. Acinetobacter johnsonii and Acrobacter cryaerophilus were the two dominant species found in septic tank effluent, comprising 20% and 11% of the library respectively. In soil samples collected from the infiltrative surface of a column dosed with STE, there was no dominant bacterial species present. Percolate samples collected from the outflow of the column showed that a tuber borchii symbiont, a common soil microorganism, dominated the bacterial

  2. REVIEW OF MATHEMATICAL MODELING FOR EVALUATING SOIL VAPOR EXTRACTION SYSTEMS

    EPA Science Inventory

    Soil vapor extraction (SVE) is a commonly used remedial technology at sites contaminated with volatile organic compounds (VOC5) such as chlorinated solvents and hydrocarbon fuels. Modeling tools are available to help evaluate the feasibility, design, and performance of SVE system...

  3. Soil quality and the solar corridor crop system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The solar corridor crop system (SCCS) is designed for improved crop productivity based on highly efficient use of solar radiation by integrating row crops with drilled or solid-seeded crops in broad strips (corridors) that also facilitate establishment of cover crops for year-round soil cover. The S...

  4. Soil Quality and the Solar Corridor Crop System

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The solar corridor crop system (SCCS) is designed for improved crop productivity based on highly efficient use of solar radiation by integrating row crops with drilled or solid-seeded crops in broad strips (corridors) that also facilitate establishment of cover crops for year-round soil cover. The S...

  5. Identifying root exudates in field contaminated soil systems

    NASA Astrophysics Data System (ADS)

    Rosenfeld, C.; Martinez, C. E.

    2012-12-01

    surface was covered by CO2 impermeable sheets to ensure that all 13C in the soil results from photoassimilated C released by roots and not soil-atmosphere gas exchange. Ambient CO2 was drawn down in the system until the CO2 concentration within the tent was less than 50 ppm, after which the labeled 13CO2 was introduced, returning the CO2 concentration to the ambient level (~375 ppm). The CO2 pulse lasted for 60 minutes to allow enough time for 13C assimilation within the plants. In order to determine the ideal sampling time, soil pore water samples were extracted every 1-2 hours following the 13C pulse application, over the course of 24 hours. Samples were analyzed for delta 13C as well as %C, and results indicate that the greatest plant-derived dissolved organic C is present at about 6 hours following the 13C pulse. A second experiment will also be conducted using a combination of NMR and mass spectrometry methods to obtain detailed information regarding chemical structures within exudate samples.

  6. 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.

  7. Behaviour of mesotrione in maize and soil system and its influence on soil dehydrogenase activity.

    PubMed

    Kaczynski, Piotr; Lozowicka, Bozena; Hrynko, Izabela; Wolejko, Elzbieta

    2016-11-15

    The aim of this study was to investigate the dissipation of mesotrione and effect on dehydrogenase activity (DHA) in maize and soil system. The paper for the first time describes behaviour of this herbicide applied at various doses (separately or in mixture with other herbicide) in acidic and alkaline environment. The experiments were conducted using the method randomized blocks in four repetition cycles. Chemical application in seven variants at recommended doses of herbicide were performed. The sample preparation was performed by a modified QuEChERS method and the concentrations of mesotrione in maize and soil were determined by the liquid chromatography with tandem mass spectrometry (LC-MS/MS). The limit of detection was 0.0005mgkg(-1) and quantification 0.001mgkg(-1). The dissipation of mesotrione were described according to first-order (FO) kinetics equation with R(2) were between 0.8794 and 0.9934. The initial deposit of herbicide in soil and maize was higher in an acidic environment (0.06-0.18mgkg(-1)). A positive correlation between an alkaline pH and the rate of dissipation in soil was observed. The results showed that the time after which 50% (DT50) of substance has been degraded was different for both plant and soil. DT50 for soil was within the range 3.2-6.0days and 2.9-4.4days, for the maize 3.9-4.8days and 3.4-4.5days in an alkaline and an acidic environment, respectively. Concentration of mesotrione at applicable MRL level of 0.05mgkg(-1) in maize was achieved at 0.5-5.9days and at proposed MRL of 0.01mgkg(-1) at 8.8-15.8days. The results indicate that the application of mesotrione affected on DHA in the soil. One day after application this herbicide, concentration of DHA in soil was lower than in control plots, but after 21days was observed trend of increasing DHA. PMID:27492351

  8. 75 FR 75961 - Notice of Implementation of the Wind Erosion Prediction System for Soil Erodibility System...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-07

    ... computer model that predicts soil erosion via simulation of the fundamental processes controlling wind erosion. WEPS can calculate soil movement, estimate plant damage, and predict PM-10 emissions when wind... Natural Resources Conservation Service Notice of Implementation of the Wind Erosion Prediction System...

  9. Data acquisition system for soil degradation measurements in sloping vineyard

    NASA Astrophysics Data System (ADS)

    Bidoccu, Marcella; Opsi, Francesca; Cavallo, Eugenio

    2013-04-01

    The agricultural management techniques and mechanization adopted in sloping areas under temperate and sub-continental climate can affect the physical and hydrological characteristics of the soil with an increase of the soil erosion rates. Vineyards have been reported among the land uses most prone to erosion. Agricultural operations can be conducted to enhance the soil conservation, it is therefore important to know the site-specific characteristics and conditions of adopted practices. A long-term monitoring to evaluate the influence of management systems in hilly vineyard on erosion and runoff and soil properties has been carried out in the north-western Italy since 2000. Three different inter-rows tillage systems were compared: conventional tillage (CT), reduced tillage (RT) and controlled grass cover (GC). To record the rainfall amount and duration, an agro-meteorological station was located near experimental plots. The three plots are hydraulically isolated, thus runoff and sediment have been collected at the bottom by a drain, connected with a tipping bucket device to measure the discharge of runoff. The system was implemented with electromagnetic counters that allow the automatic accounting with data capture by a control unit, powered by a photovoltaic panel and transmitted to a data collection center for remote viewing via web page. A portion of the runoff-sediment mixture was usually sampled and analyzed for soil and nutrients losses. In order to analyze with more detail the erosion process by means of predictive models, a micro-plot system was placed in the experimental site in 2012. Splash cups have been installed in each plot since 2011 to evaluate how the soil management affects the in-field splash erosion process. Rapid measurement of soil moisture content and temperature were performed starting from August 2011 to allow continuous monitoring of parameters that can provide an evaluation of space-time hydrological processes, determining the surface

  10. Contributions of Precipitation and Soil Moisture Observations to the Skill of Soil Moisture Estimates in a Land Data Assimilation System

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf H.; Liu, Qing; Bindlish, Rajat; Cosh, Michael H.; Crow, Wade T.; deJeu, Richard; DeLannoy, Gabrielle J. M.; Huffman, George J.; Jackson, Thomas J.

    2011-01-01

    The contributions of precipitation and soil moisture observations to the skill of soil moisture estimates from a land data assimilation system are assessed. Relative to baseline estimates from the Modern Era Retrospective-analysis for Research and Applications (MERRA), the study investigates soil moisture skill derived from (i) model forcing corrections based on large-scale, gauge- and satellite-based precipitation observations and (ii) assimilation of surface soil moisture retrievals from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E). Soil moisture skill is measured against in situ observations in the continental United States at 44 single-profile sites within the Soil Climate Analysis Network (SCAN) for which skillful AMSR-E retrievals are available and at four CalVal watersheds with high-quality distributed sensor networks that measure soil moisture at the scale of land model and satellite estimates. The average skill (in terms of the anomaly time series correlation coefficient R) of AMSR-E retrievals is R=0.39 versus SCAN and R=0.53 versus CalVal measurements. The skill of MERRA surface and root-zone soil moisture is R=0.42 and R=0.46, respectively, versus SCAN measurements, and MERRA surface moisture skill is R=0.56 versus CalVal measurements. Adding information from either precipitation observations or soil moisture retrievals increases surface soil moisture skill levels by IDDeltaR=0.06-0.08, and root zone soil moisture skill levels by DeltaR=0.05-0.07. Adding information from both sources increases surface soil moisture skill levels by DeltaR=0.13, and root zone soil moisture skill by DeltaR=0.11, demonstrating that precipitation corrections and assimilation of satellite soil moisture retrievals contribute similar and largely independent amounts of information.

  11. Optimization of contaminant removal for heterogeneous systems by soil venting

    SciTech Connect

    Walton, J.C.; Casey, D.; Anker, C.; LeMone, D.

    1996-12-31

    The efficiency of remediation of vadose zone organic compounds can be enhanced by refinement of methods for soil venting and bioventing in complex heterogeneous systems. This can be accomplished by (a) identification of physical and chemical conditions (e.g., soil temperature, moisture content, flow rates) required for rapid contaminant removal rates, (b) precise engineering control of identified parameters in the subsurface, and (c) development of knowledge-based operational strategies providing greater removal efficiencies at low cost. One method with promise is to moderately heat and humidify the input/replacement air during venting. Initial calculations indicate that this strategy may be quite effective in enhancing remediation of heterogeneous systems with diffusional control of cleanup time.

  12. Physical separations soil washing system cold test results

    SciTech Connect

    McGuire, J.P.

    1993-07-28

    This test summary describes the objectives, methodology, and results of a physical separations soil-washing system setup and shakedown test using uncontaminated soil. The test is being conducted in preparation for a treatability test to be conducted in the North Pond of the 300-FF-1 Operable Unit. It will be used to assess the feasibility of using a physical separations process to reduce the volume of contaminated soils in the 300-FF-1 Operable Unit. The test is described in DOE-RL (1993). The setup test was conducted at an uncontrolled area located approximately 3.2 km northwest of the 300-FF-1 Operable Unit. The material processed was free of contamination. The physical separation equipment to be used in the test was transferred to the US Department of Energy (DOE) by the US Environmental Protection Agency (EPA) Risk Reduction Engineering Laboratory. On May 13, 1993, soil-washing equipment was moved to the cold test location. Design assistance and recommendation for operation was provided by the EPA.

  13. A compositional shift in the soil microbiome induced by tetracycline, sulfamonomethoxine and ciprofloxacin entering a plant-soil system.

    PubMed

    Lin, Hui; Jin, Danfeng; Freitag, Thomas E; Sun, Wanchun; Yu, Qiaogang; Fu, Jianrong; Ma, Junwei

    2016-05-01

    Antibiotics entering the soil likely disturb the complex regulatory network of the soil microbiome, which is closely associated with soil quality and ecological function. This study investigated the effects of tetracycline (TC), sulfamonomethoxine (SMM), ciprofloxacin (CIP) and their combination (AM) on the bacterial community in a soil-microbe-plant system and identified the main bacterial responders. Antibiotic effects on the soil microbiome depended on antibiotic type and exposure time. TC resulted in an acute but more rapidly declining effect on soil microbiome while CIP and SMM led to a delayed antibiotic effect. The soil exposed to AM presented a highly similar bacterial structure to that exposed to TC rather than to SMM and CIP. TC, SMM and CIP had their own predominantly impacted taxonomic groups that include both resistance and sensitive bacteria. The antibiotic sensitive responders predominantly distributed within the phylum Proteobacteria. The potential bacteria resistant to each antibiotic exhibited phyla preference to some extent, particularly those resistant to TC. CIP and SMM resistance in soil was increased with exposure time while TC resistance gave the opposite result. Overall, the work extended the understanding of antibiotic effects on soil microbiome after introduced into the soil during greenhouse vegetable cultivation. PMID:26952272

  14. "Hot background" of the mobile inelastic neutron scattering system for soil carbon analysis.

    PubMed

    Kavetskiy, Aleksandr; Yakubova, Galina; Prior, Stephen A; Torbert, H Allen

    2016-01-01

    The problem of gamma spectrum peak identification arises when conducting soil carbon analysis using the inelastic neutron scattering (INS) system. Some spectral peaks could be associated with radioisotopes appearing due to neutron activation of both the measurement system and soil samples. The investigation of "hot background" gamma spectra from the construction materials, whole measurement system, and soil samples over time showed that activation of (28)Al isotope can contribute noticeable additions to the soil neutron stimulated gamma spectra. PMID:26595773

  15. Silicon Isotopic Fractionation in a Tropical Soil-Plant System

    NASA Astrophysics Data System (ADS)

    Opfergelt, S.; Delstanche, S.; Cardinal, D.; Andre, L.; Delvaux, B.

    2006-12-01

    Silica fluxes to soil solutions and water streams are controlled by both abiotic and biotic processes occurring in a Si soil-plant cycle that can be significant in comparison with Si weathering input and hydrological output. The quantification of Si-isotopic fractionation by these processes is highly promising to study the Si soil-plant cycle. Therein, the fate of aqueous monosilicic acid H4SiO4, as produced by silicate weathering, may take four paths: (1) uptake by plants and recycling through falling litter, (2) formation of clay minerals, (3) specific adsorption onto Al and Fe oxides, (4) leaching in drainage waters and export from watersheds. Here we report on detailed Si-isotopic compositions of various Si pools in a tropical soil-plant system involving old stands of banana (Musa acuminata Colla, cv Grande Naine) cropped on a weathering sequence of soils derived from andesitic volcanic ash and pumice deposits in Cameroon, West Africa. Si-isotopic compositions were measured by MC-ICP-MS in dry plasma mode with external Mg doping with a reproducibility of 0.08 permil (2stdev). Results were expressed as delta29Si vs NBS28. The compositions were determined in plant parts, bulk soils, clay fractions (less than 2um) and stream waters used for crop irrigation. Of the weathering sequence, we selected young (Y) and old (O) volcanic soils (vs). Yvs are rich in weatherable minerals, and contain large amounts of pumice gravels; their clay fraction (10-35 percent) contains allophane, halloysite and ferrihydrite. Oppositely, Ovs are strongly weathered and fine clayey soils (75-96 percent clay) rich in halloysite, kaolinite, gibbsite and goethite. Intra-plant fractionation between roots and shoots and within shoots confirmed our previous data measured on banana plants grown in hydroponics. The bulk plant isotopic composition was heavier at Ovs than at Yvs giving a fractionation factor per atomic mass unit between plants and their irrigation water Si source (+0.61 permil) of

  16. Cadmium Isotope Fractionation in Soil-Wheat Systems.

    PubMed

    Wiggenhauser, Matthias; Bigalke, Moritz; Imseng, Martin; Müller, Michael; Keller, Armin; Murphy, Katy; Kreissig, Katharina; Rehkämper, Mark; Wilcke, Wolfgang; Frossard, Emmanuel

    2016-09-01

    Analyses of stable metal isotope ratios constitute a novel tool in order to improve our understanding of biogeochemical processes in soil-plant systems. In this study, we used such measurements to assess Cd uptake and transport in wheat grown on three agricultural soils under controlled conditions. Isotope ratios of Cd were determined in the bulk C and A horizons, in the Ca(NO3)2-extractable Cd soil pool, and in roots, straw, and grains. The Ca(NO3)2-extractable Cd was isotopically heavier than the Cd in the bulk A horizon (Δ(114/110)Cdextract-Ahorizon = 0.16 to 0.45‰). The wheat plants were slightly enriched in light isotopes relative to the Ca(NO3)2-extractable Cd or showed no significant difference (Δ(114/110)Cdwheat-extract = -0.21 to 0.03‰). Among the plant parts, Cd isotopes were markedly fractionated: straw was isotopically heavier than roots (Δ(114/110)Cdstraw-root = 0.21 to 0.41‰), and grains were heavier than straw (Δ(114/110)Cdgrain-straw = 0.10 to 0.51‰). We suggest that the enrichment of heavy isotopes in the wheat grains was caused by mechanisms avoiding the accumulation of Cd in grains, such as the chelation of light Cd isotopes by thiol-containing peptides in roots and straw. These results demonstrate that Cd isotopes are significantly and systematically fractionated in soil-wheat systems, and the fractionation patterns provide information on the biogeochemical processes in these systems.

  17. Cadmium Isotope Fractionation in Soil-Wheat Systems.

    PubMed

    Wiggenhauser, Matthias; Bigalke, Moritz; Imseng, Martin; Müller, Michael; Keller, Armin; Murphy, Katy; Kreissig, Katharina; Rehkämper, Mark; Wilcke, Wolfgang; Frossard, Emmanuel

    2016-09-01

    Analyses of stable metal isotope ratios constitute a novel tool in order to improve our understanding of biogeochemical processes in soil-plant systems. In this study, we used such measurements to assess Cd uptake and transport in wheat grown on three agricultural soils under controlled conditions. Isotope ratios of Cd were determined in the bulk C and A horizons, in the Ca(NO3)2-extractable Cd soil pool, and in roots, straw, and grains. The Ca(NO3)2-extractable Cd was isotopically heavier than the Cd in the bulk A horizon (Δ(114/110)Cdextract-Ahorizon = 0.16 to 0.45‰). The wheat plants were slightly enriched in light isotopes relative to the Ca(NO3)2-extractable Cd or showed no significant difference (Δ(114/110)Cdwheat-extract = -0.21 to 0.03‰). Among the plant parts, Cd isotopes were markedly fractionated: straw was isotopically heavier than roots (Δ(114/110)Cdstraw-root = 0.21 to 0.41‰), and grains were heavier than straw (Δ(114/110)Cdgrain-straw = 0.10 to 0.51‰). We suggest that the enrichment of heavy isotopes in the wheat grains was caused by mechanisms avoiding the accumulation of Cd in grains, such as the chelation of light Cd isotopes by thiol-containing peptides in roots and straw. These results demonstrate that Cd isotopes are significantly and systematically fractionated in soil-wheat systems, and the fractionation patterns provide information on the biogeochemical processes in these systems. PMID:27485095

  18. Soil organic carbon assessments in cropping systems using isotopic techniques

    NASA Astrophysics Data System (ADS)

    Martín De Dios Herrero, Juan; Cruz Colazo, Juan; Guzman, María Laura; Saenz, Claudio; Sager, Ricardo; Sakadevan, Karuppan

    2016-04-01

    Introduction of improved farming practices are important to address the challenges of agricultural production, food security, climate change and resource use efficiency. The integration of livestock with crops provides many benefits including: (1) resource conservation, (2) ecosystem services, (3) soil quality improvements, and (4) risk reduction through diversification of enterprises. Integrated crop livestock systems (ICLS) with the combination of no-tillage and pastures are useful practices to enhance soil organic carbon (SOC) compared with continuous cropping systems (CCS). In this study, the SOC and its fractions in two cropping systems namely (1) ICLS, and (2) CCS were evaluated in Southern Santa Fe Province in Argentina, and the use of delta carbon-13 technique and soil physical fractionation were evaluated to identify sources of SOC in these systems. Two farms inside the same soil cartographic unit and landscape position in the region were compared. The ICLS farm produces lucerne (Medicago sativa Merrill) and oat (Avena sativa L.) grazed by cattle alternatively with grain summer crops sequence of soybean (Glicine max L.) and corn (Zea mays L.), and the farm under continuous cropping system (CCS) produces soybean and corn in a continuous sequence. The soil in the area is predominantly a Typic Hapludoll. Soil samples from 0-5 and 0-20 cm depths (n=4) after the harvest of grain crops were collected in each system and analyzed for total organic carbon (SOC, 0-2000 μm), particulate organic carbon (POC, 50-100 μm) and mineral organic carbon (MOC, <50 μm). Delta carbon-13 was determined by isotopic ratio mass spectrometry. In addition, a site with natural vegetation (reference site, REF) was also sampled for delta carbon-13 determination. ANOVA and Tukey statistical analysis were carried out for all data. The SOC was higher in ICLS than in CCS at both depths (20.8 vs 17.7 g kg-1 for 0-5 cm and 16.1 vs 12.7 g kg-1 at 0-20 cm, respectively, P<0.05). MOC was

  19. Soil quality index as affected by different cropping systems in northwestern Himalayas.

    PubMed

    Sofi, J A; Bhat, A G; Kirmai, N A; Wani, J A; Lone, Aabid H; Ganie, Mumtaz A; Dar, G I H

    2016-03-01

    Soil quality assessment provides a tool for evaluating the sustainability of soils under different crop cafeterias. Our objective was to develop the soil quality index for evaluating the soil quality indicators under different cropping systems in northwest Himalaya-India. Composite soil samples were taken from the study area from different cropping systems which include T1 (forest soil control), T2 (rice-oilseed, lower belts), T3 (rice-oilseed, higher belts), T4 (rice-oats), T5 (rice-fallow), T6 (maize-oats), T7 (maize-peas), T8 (apple), T9 (apple-beans), and T10 (apple-maize). Physical, chemical, and biological soil indicators were determined, and it was found that soil enzyme activities involved in nutrient cycling were significantly higher in forest soils, which were reflected in higher levels of available pool of nutrients. Carbon stocks were found significantly higher in forest soil which was translated in improved soil physical condition. Principal component analysis (PCA) was performed to reduce multidimensionality of data followed by scoring by homothetic transformation of the selected indicators. Pearson's interclass correlation was performed to avoid redundancy, and highly correlated variables were not retained. Inclusion of legumes in the apple orchard floor recorded highest soil quality rating across the treatments. Cereal-based cropping systems were found in lower soil quality rating; however, the incorporation of peas in the system improved soil health.

  20. Continuous Cropping Systems Reduce Near-Surface Maximum Compaction in No-Till Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Because of increased concerns over compaction in NT soils, it is important to assess how continuous cropping systems influence risks of soil compaction across a range of soils and NT management systems. We quantified differences in maximum bulk density (BDmax) and critical water content (CWC) by the...

  1. Identifying constraints to potato system sustainability: soil and plant growth relationships

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potato yield in Maine has remained relatively constant for over 50 years, despite increased production inputs. We evaluated Status Quo (SQ), Soil Conserving (SC), Soil Improving (SI), and Disease Suppressive (DS) potato systems to identify limitations to sustainability. Soil in the SI System had the...

  2. Test of Regional Calibrations for a NIRS Soil Mapping System

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Near infrared spectroscopy (NIRS) is an effective technique for simultaneously measuring several soil properties including soil organic carbon, total nitrogen, moisture, and cation exchange capacity. However, developing robust calibration models for predicting soil properties from spectral measureme...

  3. Collaboration support system for "Phobos-Soil" space mission.

    NASA Astrophysics Data System (ADS)

    Nazarov, V.; Nazirov, R.; Zakharov, A.

    2009-04-01

    Rapid development of communication facilities leads growth of interactions done via electronic means. However we can see some paradox in this segment in last times: Extending of communication facilities increases collaboration chaos. And it is very sensitive for space missions in general and scientific space mission particularly because effective decision of this task provides successful realization of the missions and promises increasing the ratio of functional characteristic and cost of mission at all. Resolving of this problem may be found by using respective modern technologies and methods which widely used in different branches and not in the space researches only. Such approaches as Social Networking, Web 2.0 and Enterprise 2.0 look most prospective in this context. The primary goal of the "Phobos-Soil" mission is an investigation of the Phobos which is the Martian moon and particularly its regolith, internal structure, peculiarities of the orbital and proper motion, as well as a number of different scientific measurements and experiments for investigation of the Martian environment. A lot of investigators involved in the mission. Effective collaboration system is key facility for information support of the mission therefore. Further to main goal: communication between users of the system, modern approaches allows using such capabilities as self-organizing community, user generated content, centralized and federative control of the system. Also it may have one unique possibility - knowledge management which is very important for space mission realization. Therefore collaboration support system for "Phobos-Soil" mission designed on the base of multilayer model which includes such levels as Communications, Announcement and Information, Data sharing and Knowledge management. The collaboration support system for "Phobos-Soil" mission will be used as prototype for prospective Russian scientific space missions and the presentation describes its architecture

  4. Mechanistic understanding of MeHg-Se antagonism in soil-rice systems: the key role of antagonism in soil

    NASA Astrophysics Data System (ADS)

    Wang, Yongjie; Dang, Fei; Evans, R. Douglas; Zhong, Huan; Zhao, Jiating; Zhou, Dongmei

    2016-01-01

    Methylmercury (MeHg) accumulation in rice has great implications for human health. Here, effects of selenium (Se) on MeHg availability to rice are explored by growing rice under soil or foliar fertilization with Se. Results indicate that soil amendment with Se could reduce MeHg levels in soil and grain (maximally 73%). In contrast, foliar fertilization with Se enhanced plant Se levels (3-12 folds) without affecting grain MeHg concentrations. This evidence, along with the distinct distribution of MeHg and Se within the plant, demonstrate for the first time that Se-induced reduction in soil MeHg levels (i.e., MeHg-Se antagonism in soil) rather than MeHg-Se interactions within the plant might be the key process triggering the decreased grain MeHg levels under Se amendment. The reduction in soil MeHg concentrations could be mainly attributed to the formation of Hg-Se complexes (detected by TEM-EDX and XANES) and thus reduced microbial MeHg production. Moreover, selenite and selenate were equally effective in reducing soil MeHg concentrations, possibly because of rapid changes in Se speciation. The dominant role of Se-induced reduction in soil MeHg levels, which has been largely underestimated previously, together with the possible mechanisms advance our mechanistic understanding about MeHg dynamics in soil-rice systems.

  5. Mechanistic understanding of MeHg-Se antagonism in soil-rice systems: the key role of antagonism in soil

    PubMed Central

    Wang, Yongjie; Dang, Fei; Evans, R. Douglas; Zhong, Huan; Zhao, Jiating; Zhou, Dongmei

    2016-01-01

    Methylmercury (MeHg) accumulation in rice has great implications for human health. Here, effects of selenium (Se) on MeHg availability to rice are explored by growing rice under soil or foliar fertilization with Se. Results indicate that soil amendment with Se could reduce MeHg levels in soil and grain (maximally 73%). In contrast, foliar fertilization with Se enhanced plant Se levels (3–12 folds) without affecting grain MeHg concentrations. This evidence, along with the distinct distribution of MeHg and Se within the plant, demonstrate for the first time that Se-induced reduction in soil MeHg levels (i.e., MeHg-Se antagonism in soil) rather than MeHg-Se interactions within the plant might be the key process triggering the decreased grain MeHg levels under Se amendment. The reduction in soil MeHg concentrations could be mainly attributed to the formation of Hg-Se complexes (detected by TEM-EDX and XANES) and thus reduced microbial MeHg production. Moreover, selenite and selenate were equally effective in reducing soil MeHg concentrations, possibly because of rapid changes in Se speciation. The dominant role of Se-induced reduction in soil MeHg levels, which has been largely underestimated previously, together with the possible mechanisms advance our mechanistic understanding about MeHg dynamics in soil-rice systems. PMID:26778218

  6. [Establishment of ARDRA system for Panax ginseng cultivated soil microbial community study].

    PubMed

    Ying, Yixin; Ding, Wanlong; Li, Yong

    2011-02-01

    In this study, ARDRA system was established for Panax ginseng cultivated soil microbial community analysis. In the process of soil analysis we found that, ARDRA can not only distinguish soil microbial communities, proportion of each microbial type in total microorganisms can be calculated based on profiles of restricted enzyme digested 16S rDNA, also. Results indicated that, ARDRA system established was able to analyze microbial communities of P. ginseng cultivated soil samples.

  7. Dynamic modeling and response of soil-wall systems

    SciTech Connect

    Veletsos, A.S.; Younan, A.H.

    1993-10-01

    The study reported herein is the third in a series of investigations motivated by need to gain improved understanding of the responses to earthquakes of deeply embedded and underground tanks storing radioactive wastes, and to develop rational but simple methods of analysis and design for such systems. Following a brief review of the errors that may result from the use of a popular model for evaluating the dynamic soil forces induced in a base-excited rigid wall retaining an elastic stratum, the sources of the errors are identified and a modification is proposed which defines correctly the action of the system. In the proposed modification, the stratum is modeled by a series of elastically supported, semi-infinite horizontal bars with distributed mass instead of massless springs. The concepts involved are introduced by reference to a system composed of a fixed-based wall and a homogeneous elastic stratum, and are then applied to the analysis of more complex soil-wall systems. Both harmonic and transient excitations are considered, and comprehensive numerical solutions are presented which elucidate the actions involved and the effects and relative importance of the relevant parameters.

  8. The maintenance of soil fertility in Amazonian managed systems

    NASA Astrophysics Data System (ADS)

    Luizão, Flávio J.; Fearnside, Philip M.; Cerri, Carlos E. P.; Lehmann, Johannes

    Most of Brazilian Amazonia faces important limitations for conventional agriculture and pastures due to a generally poor chemical fertility as well as the region's environmental conditions, especially high temperature and moisture. Without proper management, degradation of the soil and resulting unsustainability of agricultural and ranching production occur within a few years, leading to land abandonment. Use of perennial crops, especially those based on native tree species, would be instrumental in order to achieve best management such as that which assure recycling processes similar to those in the primary forest. Recommended alternative land uses are those producing high soil organic matter, recycling of nutrients, substantial agricultural production, and economic viability. These include agroforestry systems, enrichment of second growth with valuable native timber or fruit species, accelerated fallow regrowth via enrichment plantings, sequential agroforestry with slash-and-mulch, and diversified forest plantations. Improvement of agricultural soils can be based on lessons learned from the study of processes involved in the formation and maintenance of the rich "dark earths" (terra preta), which owe their high carbon content and fertility in part to high content of charcoal. Adding powdered charcoal combined with selected nutrients can increase soil carbon in modern agriculture. Considering that limitations to expansion of intensified land uses in Amazonia are serious, regional development should emphasize the natural forest, which can maintain itself without external inputs of nutrients. Instead of creating conditions to further expand deforestation, these forests may be used as they stand to provide a variety of valuable environmental services that could offer a sustainable basis for development of Amazonia.

  9. Soil surface roughness decay in contrasting climates, tillage types and management systems

    NASA Astrophysics Data System (ADS)

    Vidal Vázquez, Eva; Bertol, Ildegardis; Tondello Barbosa, Fabricio; Paz-Ferreiro, Jorge

    2014-05-01

    Soil surface roughness describes the variations in the elevation of the soil surface. Such variations define the soil surface microrelief, which is characterized by a high spatial variability. Soil surface roughness is a property affecting many processes such as depression storage, infiltration, sediment generation, storage and transport and runoff routing. Therefore the soil surface microrelief is a key element in hydrology and soil erosion processes at different spatial scales as for example at the plot, field or catchment scale. In agricultural land soil surface roughness is mainly created by tillage operations, which promote to different extent the formation of microdepressions and microelevations and increase infiltration and temporal retention of water. The decay of soil surface roughness has been demonstrated to be mainly driven by rain height and rain intensity, and to depend also on runoff, aggregate stability, soil reface porosity and soil surface density. Soil roughness formation and decay may be also influenced by antecedent soil moisture (either before tillage or rain), quantity and type of plant residues over the soil surface and soil composition. Characterization of the rate and intensity of soil surface roughness decay provides valuable information about the degradation of the upper most soil surface layer before soil erosion has been initiated or at the very beginning of soil runoff and erosion processes. We analyzed the rate of decay of soil surface roughness from several experiments conducted in two regions under temperate and subtropical climate and with contrasting land use systems. The data sets studied were obtained both under natural and simulated rainfall for various soil tillage and management types. Soil surface roughness decay was characterized bay several parameters, including classic and single parameters such as the random roughness or the tortuosity and parameters based on advanced geostatistical methods or on the fractal theory. Our

  10. The impact of pyrogenic C on soil functioning : a study using ancient killn soil as a model system

    NASA Astrophysics Data System (ADS)

    Rumpel, Cornelia; Naisse, Christophe; Thi Ngo, Phuong; Davasse, Bernard; Girardin, Cyril; Chabbi, Abad

    2016-04-01

    The long-term effect of pyrogenic C on the physicochemical and biological functioning of soils is poorly understood. We used ancient killn soils as model systems in order to investigate soil properties after four centuries of pyrogenic C addition. In particular we were interested in the effect of the pyrogenic C amendment on the (micro-)biological functioning of the soil. We analysed for physicochemical properties, C mineralisation as well as C dynamics following input of 13C labelled charcoal and plant residues. Our results show compared to soil without any addition, that pyrogenic C amendment led in the long term to more rapid decomposition of the new materials. The decomposition rate was increased by about 17%. In contrast,a negative priming effect reduced soil organic carbon mineralization by about 30%. Soil physicochemical poperties, i.e. clay content, cation exchange and nutrient availability were durably improved in soil amended with pyrogenic C four centuries ago. These changes probably promoted higher microbial activity and thus intense mineralization when new plant litter was added. On the contrary, charcoal was degraded at a similar rate compared to soil without pyrogenic C amendment. Thus no specific adaptation of microorganism to charcoal degradation was observed even after several centuries. The negative priming effect induced by charcoal additiion can be due to a physical protection of the soluble carbon fraction at the surfaces of new charcoal. In contrast, the negative priming effect induced by plant residue input may be more likely due to a shift of substrate utilisation by microbial communities evolving in a nutrient-rich environment. Our results demonstrate that pyrogenic C addition modifies the carbon dynamic of soils in the long-term. We propose a conceptual model accounting for the alterations of soil functioning in the long term after pyrogenic C addition.

  11. Changes of soil pore system due to soil macrofauna: an experimental approach to study the contribution of different taxa

    NASA Astrophysics Data System (ADS)

    Gargiulo, Laura; Buscemi, Gilda; Mele, Giacomo; Terribile, Fabio

    2015-04-01

    Soil fauna contributes to the ecosystem functioning, for example, by means of its direct influence on soil structure which modifies the physical environment of the microbial community. Changes in habitat structure due to soil fauna activities can influence resource availability, species' abundances, and community composition of soil microorganisms. X-ray tomography has been increasingly used to obtain precise and non-destructive analysis mostly of the macroporosity resulting from earthworm activity in repacked soil cores. However also other macrofauna species contribute in different manner and extent to the modification of soil pore system, and then to the soil functioning, by means of their burrows and bioturbation activity. In this work we have developed an experimental approach based on the use of repacked soil mesocosms specifically constructed for the purpose of distinguish separately the contribution to soil structure changes of different organisms naturally present in field or inoculated in laboratory. Six different orders of macrofauna were studied and after four weeks of fauna activity the cores were imaged using a medical X-ray tomograph. Three-dimensional image processing was used in order to obtain 3D reconstructions and preliminary analysis of the identified biopores. In addition to the earthworms (Haplotaxida, genus Lombricus), among the studied taxa, Embioptera showed the most intense burrowing activity, while Coleoptera larvae (sp. Elater sanguineus) and Julida (class Diplopoda) produced the thickest pore network in our mesocosms. The used experimental approach showed a promising potential to provide new useful information about the widely differentiated contribution of many types of macrofauna to the modification of soil pore system.

  12. Hydraulic management of a soil moisture controlled SDI wastewater dispersal system in an Alabama Black Belt soil.

    PubMed

    He, Jiajie; Dougherty, Mark; Shaw, Joey; Fulton, John; Arriaga, Francisco

    2011-10-01

    Rural areas represent approximately 95% of the 14000 km(2) Alabama Black Belt, an area of widespread Vertisols dominated by clayey, smectitic, shrink-swell soils. These soils are unsuitable for conventional onsite wastewater treatment systems (OWTS) which are nevertheless widely used in this region. In order to provide an alternative wastewater dosing system, an experimental field moisture controlled subsurface drip irrigation (SDI) system was designed and installed as a field trial. The experimental system that integrates a seasonal cropping system was evaluated for two years on a 500-m(2) Houston clay site in west central Alabama from August 2006 to June 2008. The SDI system was designed to start hydraulic dosing only when field moisture was below field capacity. Hydraulic dosing rates fluctuated as expected with higher dosing rates during warm seasons with near zero or zero dosing rates during cold seasons. Lower hydraulic dosing in winter creates the need for at least a two-month waste storage structure which is an insurmountable challenge for rural homeowners. An estimated 30% of dosed water percolated below 45-cm depth during the first summer which included a 30-year historic drought. This massive volume of percolation was presumably the result of preferential flow stimulated by dry weather clay soil cracking. Although water percolation is necessary for OWTS, this massive water percolation loss indicated that this experimental system is not able to effective control soil moisture within its monitoring zone as designed. Overall findings of this study indicated that soil moisture controlled SDI wastewater dosing is not suitable as a standalone system in these Vertisols. However, the experimental soil moisture control system functioned as designed, demonstrating that soil moisture controlled SDI wastewater dosing may find application as a supplement to other wastewater disposal methods that can function during cold seasons. PMID:21621905

  13. Long-Term Cropping System Effects on Soil Properties and on a Soil Quality Index

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Intensive row-crop production can lead to soil degradation over time if insufficient biomass return, intensive tillage, or excessive erosion lead to depletion of soil organic C. Soil quality may be improved by incorporating forage crops or grazing into the rotation, adding manure or other organic so...

  14. Soil classification and carbon storage in cacao agroforestry farming systems of Bahia, Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Information concerning the classification of soils and their properties under cacao agroforestry systems of the Atlantic rain forest biome region in the Southeast of Bahia Brazil is largely unknown. Soil and climatic conditions in this region are favorable for high soil carbon storage. This study is...

  15. Cumulative and residual effects of potato cropping system management strategies on crop and soil health parameters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil and crop management practices can greatly affect parameters related to soil health, as well as crop productivity and disease development, and may provide options for more sustainable production. Different 3-yr potato cropping systems focused on specific management goals of soil conservation (SC...

  16. Effects of easter Arkansas production systems on soil strength and electrical conductivity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eastern Arkansas cotton-growing soils are especially susceptible to soil compaction due to the large percentage of clay content present in these soils and the use of extensive tillage systems that require large equipment and frequent field trips. In this study, the effect of reduced tillage and cove...

  17. Development of an angular scanning system for sensing vertical profiles of soil electrical conductivity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Apparent soil electrical conductivity (EC**a**) is typically mapped to define soil spatial variability within an agricultural field. Knowledge of the vertical variability of EC**a** is desired to define site-specific behavior of the soil profile. A Pneumatic Angular Scanning System (PASS) was develo...

  18. Soil quality improvement under an ecologically based farming system in northwest Missouri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ecologically based farming conserves and improves the soil resource and protects environmental quality by using organic or natural resources without application of synthetic chemicals. Soil quality assessment indicates the ability of management systems to optimize soil productivity and to maintain i...

  19. Thermal performance of soils and backfills in horizontal ground coupled heat pump system applications. Final report

    SciTech Connect

    1998-04-01

    The goal of this research was to address the appropriateness of different soils, in an unsaturated state, for placement adjacent to the buried heat exchanger for GSHP systems. Soils for the study were selected based on an analysis of common soil parent materials that exist in the US in conjunction with the current EPRI soil thermal classification system. Six soils were chosen (Cecil (clay), Fordville (sand), Kranzburg (loam), Moody (silt), Sharpsburg (silt) and Vienna (sandy loam)) which provided at least one soil in each of the EPRI classifications. Initial laboratory studies were concentrated on determination of basic physical, water holding and thermal properties of each soil. Each soil was evaluated for ability to sustain thermal contact conductance under thermal loading, and comparison of the results allowed the soils to be ranked, best to worst. Additional laboratory studies were performed on each soil to rate the long-term thermal performance of each relative to potential for drying adjacent to the heat exchanger along with reduction in heat transfer rate due to soil drying. Tests were conducted over a range of initial water contents and densities that would be common for each soil. Results were used to verify a theoretical analysis of the thermal stability of each soil, based on texture, and to rank each soil according to thermal performance under extended thermal load. Results of the thermal conductivity tests, the thermal contact conductance tests and the thermal performance tests were utilized to propose a thermal performance index (TPI) for soils based on texture. The final soil ranking were then expressed relative to the EPRI soil thermal classification system which identified clay as best, followed by loam, sandy loam, silt, and sand.

  20. Rice production in relation to soil quality under different rice-based cropping systems

    NASA Astrophysics Data System (ADS)

    Tran Ba, Linh; Sleutel, Steven; Nguyen Van, Qui; Thi, Guong Vo; Le Van, Khoa; Cornelis, Wim

    2016-04-01

    Soil quality of shallow paddy soils may be improved by introducing upland crops and thus a more diverse crop cultivation pattern. Yet, the causal relationship between crop performance and enhanced soil traits in rice-upland crop rotations remains elusive. The objectives of this study were to (i) find correlations among soil properties under different rice-upland crop systems and link selected soil properties to rice growth and yield, (ii) present appropriate values of soil parameters for sustainable rice productivity in heavy clay soil, (iii) evaluate the effect of rotating rice with upland crops on rice yield and economic benefit in a long-term experiment. A rice-upland crop rotational field experiment in the Vietnamese Mekong delta was conducted for 10 years using a randomized complete block design with four treatments and four replications. Treatments were: (i) rice-rice-rice (control - conventional system as farmers' practice), (ii) rice-maize-rice, (iii) rice-mung bean-rice, and (iv) rice-mung bean-maize. Soil and plant sampling were performed after harvest of the rice crop at the end of the final winter-spring cropping season (i.e. year 10). Results show differences in rice growth and yield, and economic benefit as an effect of the crop rotation system. These differences were linked with changes in bulk density, soil porosity, soil aggregate stability index, soil penetration resistance, soil macro-porosity, soil organic carbon, acid hydrolysable soil C and soil nutrient elements, especially at soil depth of 20-30 cm. This is evidenced by the strong correlation (P < 0.01) between rice plant parameters, rice yield and soil properties such as bulk density, porosity, penetration resistance, soil organic carbon and Chydrolysable. It turned out that good rice root growth and rice yield corresponded to bulk density values lower than 1.3 Mg m-3, soil porosity higher than 50%, penetration resistance below 1.0 MPa, and soil organic carbon above 25 g kg-1. The optimal

  1. Role of unsaturated soil in a waste containment system

    SciTech Connect

    Lim, P.C.; Tay, J.H.

    1996-12-31

    The role of the unsaturated properties of sand as a drainage layer in a composite liner system for landfills is investigated. The effect of the unsaturated properties of coarse-grained soil on contaminant migration was evaluated by means of a series of simulations using a one-dimensional model of a two- and a three-layer soil liner system for advection and diffusion, respectively. The results showed that under seepage conditions, the effect of an unsaturated sand layer on the advancement of the concentration front was quite insignificant. The arrival time of the C/C{sub o} = 0.5 concentration front increased from 651 days for the case with no sand layer to approximately 951 days for the case with a 1.0-m sand layer. A steady-state flow condition was ultimately established in the sand, and this fact suggests that the capillary action might not be effective. For diffusion, the arrival time of the concentration front increased nonlinearly with a decrease in the degree of saturation and linearly with increasing depths of the sand layer. At a residual degree of saturation, the arrival times of the C/C{sub o} = 0.01 and 0.5 concentration front at the base of the 1-m sand layer were 26.9 and 877.4 years as compared to 1.52 and 2.62 years by advection, respectively. 17 refs., 11 figs.

  2. Soil physical quality changes under different management systems after 10 years in Argentinian Humid Pampa

    NASA Astrophysics Data System (ADS)

    Costa, J. L.; Aparicio, V. C.; Cerda, A.

    2014-08-01

    The Argentinian Humid Pampa extends over about 60 million ha, 90% of which are agricultural lands. The southeast of the Buenos Aires Province is part of the Humid Pampa (1 206 162 ha). The main crops are wheat, sunflower, corn and soybean. The management systems used in the area are: moldboard plow (MP), chisel plow (CP) and no-till (NT). Excessive soil cultivation under MP causes decreases in the soil organic carbon content (SOC). Adopting NT may reduce the effects of intensive agriculture, through the maintenance and accumulation of SOC. However, the soil compaction under NT causes degradation of the soil structure, reduces the soil water availability and reduces the soil hydraulic conductivity. We evaluated the evolution of the soil physical parameters in three management systems. After 10 years of experiments in four farmers' fields, we found that: soil bulk density was significantly higher under NT. The change in mean weight diameter (CMWD) of aggregates increased as the management system became more intensive. We did not find significant differences in time and management systems in hydraulic conductivity at tension (h)0 cm and h=20 cm. The reduction in total porosity under NT is mainly a product of a reduction in the percentage of mesopores in the soil. Time had no statistically significant effect on the SOC content. The management system did not affect the yields of crop. In this work, the results indicate a modification of some soil physical parameters (porosity, near-saturated hydraulic conductivity, soil structure) due to uninterrupted agricultural production.

  3. Organic cotton systems improved soil properties vis-a-vis the modern systems

    NASA Astrophysics Data System (ADS)

    Blaise, D.; Venugopalan, M. V.; Singh, J. V.; Narkhedkar, N. G.; Velmourougane, K.

    2012-04-01

    India is the largest cotton growing country in the world. Traditionally, cotton in India was grown with minimal inputs and resources available on farm were put to efficient use. Advent of hybrids and Bt cotton revolutionized cotton production in the country and lead to heavy reliance on external inputs. However, there is a growing awareness of the detrimental effects of excessive use of pesticides and fertilizers. This is leading to growing interest in organic cultivation of crops. An organic system (OS) was compared with the modern systems (MS) for changes in the soil physical, chemical and biological properties in field experiments conducted both on station and farmers fields in Maharashtra, India on rain dependent cotton grown on Vertisols. Soil samples of the organic plots had significantly greater C content than the MS plots relying on mineral fertilizers and pesticides. Similarly, other nutrients were also greater in the OS than the MS across locations. Most of the increases were noticed in the top 30 cm of the soil profile. Interestingly, enrichment of the soil at lower depths was noticed in the OS which could be due to the surface creep of soils through the cracks in the Vertisols. With regard to the physical properties, water-stable aggregates and mean weight diameter in the MS were significantly lesser than the OS. Differences were restricted to the top 20 cm. Soil biological properties of the two systems were compared through the enzyme assays such as the dehydrogenase, glucosidase, phosphatase, sulfatase periodically during the crop growing season. All the enzyme assays indicated greater activities in the OS than the MS. Further, microfauna (nematodes) monitored indicated less of plant parasitic nematodes in the OS than the MS. Excessive tillage followed in the MS did bring about a reduction in the nematode numbers. But the systems had more parasitic nematodes.

  4. Predicting Boron, Molybdenum, Selenium, and Arsenic Adsorption in Soil Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A chemical surface complexation model was applied to boron, molybdenum, selenium, and arsenic adsorption on up to 49 soils selected for variation in soil properties. The surface complexation model was able to fit boron, molybdenum, selenite, and arsenate adsorption on the soils. General regression...

  5. Performance of in situ soil venting system at jet fuel spill site

    SciTech Connect

    DePaoli, D.W.; Herbes, S.E.; Elliott, M.G.

    1989-01-01

    The Air Force Engineering and Services Center and Oak Ridge National Laboratory (ORNL) are performing a field demonstration of in situ venting at a 27,000-gal jet fuel spill site at Hill Air Force Base (AFB), Utah. In situ soil venting is a soil cleanup techniques that uses vacuum blowers to pull large volumes of air through contaminated soil. The air flow sweeps out the soil gas, disrupting the equilibrium existing between the contaminants on the soil and in the vapor. This causes volatilization of the contaminant and subsequent removal in the air stream. In situ soil venting has been used for removing volatile contaminants such as gasoline and trichloroethylene, but a full-scale demonstration for removing jet fuel from soil has not been reported. This paper briefly describes the jet fuel spill site and the design and results to date of our full-scale in situ soil venting system. 8 refs., 9 figs.

  6. Study of soil moisture sensor for landslide early warning system: Experiment in laboratory scale

    NASA Astrophysics Data System (ADS)

    Yuliza, E.; Habil, H.; Munir, M. M.; Irsyam, M.; Abdullah, M.; Khairurrijal

    2016-08-01

    The high rate of rainfall is the main trigger factor in many cases of landslides. However, each type of soils has unique characteristics and behavior concerning the rainfall infiltration. Therefore, early warning system of landslide will be more accurate by monitoring the changes of ground water condition. In this study, the monitoring of ground water changes was designed by using soil moisture sensor and simple microcontroller for data processing. The performance of soil moisture sensor was calibrated using the gravimetric method. To determine the soil characteristic and behavior with respect to water content that induce landslides, an experiment involving small-scale landslide model was conducted. From these experiments, the electric resistance of the soil increased as soil water content increases. The increase of soil water content led to the rise of the pore pressure and soil weight which could cause soil vulnerability to the movement. In addition, the various soil types were used to determine the responses of soils that induce the slope failure. Experimental results showed that each type of soils has different volumetric water content, soil matrix suction and shear strength of the slope. This condition influenced the slope stability that trigger of landslide.

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

    PubMed

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

    2015-07-15

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

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

    PubMed

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

    2015-07-15

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

  9. Soil Management Effects on Gas Fluxes from an Organic Soil Agricultural System

    NASA Astrophysics Data System (ADS)

    Jennewein, S. P.; Bhadha, J. H.; Lang, T. A.; Singh, M.; Daroub, S. H.; McCray, M.

    2015-12-01

    The role of soil management on gas flux isn't well understood for Histosols of the Everglades Agricultural Area (EAA) of southern Florida. The region is responsible for roughly half of sugarcane (Saccharum spp. hybrids) production in the USA along with supplying winter vegetable crops to the eastern USA. Future productivity in the EAA is jeopardized by soil subsidence resulting from oxidation of organic matter. Establishing the role of tillage, water-table depth, nitrogen fertilizer, and soil depth on gas flux will help determine how effective various managements are on conserving soil. Ongoing lysimeter and field studies examined effects of management practices (water-table, tillage, and nitrogen fertilizer), and soil depth on, gas emission and microbial biomass. The trials were set in Belle Glade, FL, on Lauderhill muck (Lithic Haplosaprists). Results to be presented include soil microbial biomass and soil gas (CO2, CH4, and N2O) flux. This study provides insight into management effectiveness and agriculture sustainability on shallow muck soils of the EAA and will help farmers mitigate problems associated with soil subsidence and seasonally high water-tables.

  10. Anaerobic soil disinfestation and Brassica seed meal amendment alter soil microbiology and system resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Brassica seed meal amendments and anaerobic soil disinfestation control a spectrum of soil-borne plant pathogens via a diversity of mechanisms. Transformations in microbial community structure and function in certain instances were determinants of disease control and enhanced plant performance. Fo...

  11. Volatilization of lindance from water in soil-free and flooded soil systems.

    PubMed

    Siddaramppa, R; Sethunathan, N

    1976-01-01

    Volatilization of 14C-lindane from water in planchets and under flooded soil ecosystem was investigated. Lindane disappeared faster than parathion from planchets. More rapid loss of both insecticides occurred from water than from chloroform. Loss of lindane and parathion was related to measured losses of water by evaporation. During 5-day incubation under flooded soil conditions, disappearance of lindane was faster from open vials than from sealed vials, whereas in nonflooded soil, no volatile loss of the insecticide was evident despite water evaporation. Over 5 day incubation under flooded conditions, greater volatile loss of lindane occurred in sandy soil than in alluvial soil apparanetly due to greater adsorption to the soil colloids decreasing the insecticide concentration in the standing water on the laterite soil. Under identical conditions of water evaporation, lindane loss was directly proportional to its initial concentration in the water. These results suggest that considerable loss of soil applied pesticides can occur by volatilization from the standing water in flooded rice fields, particularly under tropical conditions. PMID:57974

  12. Volatilization of lindance from water in soil-free and flooded soil systems.

    PubMed

    Siddaramppa, R; Sethunathan, N

    1976-01-01

    Volatilization of 14C-lindane from water in planchets and under flooded soil ecosystem was investigated. Lindane disappeared faster than parathion from planchets. More rapid loss of both insecticides occurred from water than from chloroform. Loss of lindane and parathion was related to measured losses of water by evaporation. During 5-day incubation under flooded soil conditions, disappearance of lindane was faster from open vials than from sealed vials, whereas in nonflooded soil, no volatile loss of the insecticide was evident despite water evaporation. Over 5 day incubation under flooded conditions, greater volatile loss of lindane occurred in sandy soil than in alluvial soil apparanetly due to greater adsorption to the soil colloids decreasing the insecticide concentration in the standing water on the laterite soil. Under identical conditions of water evaporation, lindane loss was directly proportional to its initial concentration in the water. These results suggest that considerable loss of soil applied pesticides can occur by volatilization from the standing water in flooded rice fields, particularly under tropical conditions.

  13. Elaboration of the Soil Degradation Subsystem of the National Environmental Information System in Hungary

    NASA Astrophysics Data System (ADS)

    Szabó, József; Pásztor, László; Dombos, Miklós; Bakacsi, Zsófia; Laborczi, Annamária; Pirkó, Béla; Szabóné Kele, Gabriella

    2010-05-01

    A successful proposal within the Environment and Energy Operational Programme for informatics development aimed at environmental protection in public administration (e-environmental protection) opened the feasibility of a program for the establishment of a national soil monitoring system for the follow up of the harmful changes in soil conditions and functioning. The aim of the project is to collect, manage, analyse and publish soil data related to the state of soils and the environmental stresses attributed to the pressures due to agriculture setting up an appropriate information system in order to fulfil the directives of the Thematic Strategy for Soil Protection. Further objective is the web-based publication of soil data as well as information to support the related public service mission and to inform publicity. The developed information system will operate as the Soil Degradation Subsystem of the National Environmental Information System being compatible with its other elements. A suitable representative sampling method will be elaborated. The representativity is meant for soil associations, landuse, agricultural practices and typical degradation processes. Soil data will be collected on county levels led by regional representatives but altogether will be representative for the whole territory of Hungary. In our present paper the scheme and conceptual model of the system is presented in the hope of getting useful criticism and ideas from the session participants, which can be built into the system before the project starts in this summer.

  14. Soil carbon stabilization and turnover at alley-cropping systems, Eastern Germany

    NASA Astrophysics Data System (ADS)

    Medinski, T.; Freese, D.

    2012-04-01

    Alley-cropping system is seen as a viable land-use practice for mitigation of greenhouse gas CO2, energy-wood production and soil carbon sequestration. The extent to which carbon is stored in soil varies between ecosystems, and depends on tree species, soil types and on the extent of physical protection of carbon within soil aggregates. This study investigates soil carbon sequestration at alley-cropping systems presented by alleys of fast growing tree species (black locust and poplar) and maize, in Brandenburg, Eastern Germany. Carbon accumulation and turnover are assessed by measuring carbon fractions differing in decomposition rates. For this purpose soil samples were fractionated into labile and recalcitrant soil-size fractions by wet-sieving: macro (>250 µm), micro (53-250 µm) and clay + silt (<53 µm), followed by determination of organic carbon and nitrogen by gas-chromatography. Soil samples were also analysed for the total C&N content, cold-water extractable OC, and microbial C. Litter decomposition was evaluated by litter bags experiment. Soil CO2 flux was measured by LiCor automated device LI-8100A. No differences for the total and stable (clay+silt, <53 µm) carbon fraction were observed between treatment. While cold water-extractable carbon was significantly higher at maize alley compared to black locust alley. This may indicate faster turnover of organic matter at maize alley due to tillage, which influenced greater incorporation of plant residues into the soil, greater soil respiration and microbial activity.

  15. Soil moisture's underestimated role in climate change impact modelling in low-energy systems.

    PubMed

    le Roux, Peter Christiaan; Aalto, Juha; Luoto, Miska

    2013-10-01

    Shifts in precipitation regimes are an inherent component of climate change, but in low-energy systems are often assumed to be less important than changes in temperature. Because soil moisture is the hydrological variable most proximally linked to plant performance during the growing season in arctic-alpine habitats, it may offer the most useful perspective on the influence of changes in precipitation on vegetation. Here we quantify the influence of soil moisture for multiple vegetation properties at fine spatial scales, to determine the potential importance of soil moisture under changing climatic conditions. A fine-scale data set, comprising vascular species cover and field-quantified ecologically relevant environmental parameters, was analysed to determine the influence of soil moisture relative to other key abiotic predictors. Soil moisture was strongly related to community composition, species richness and the occurrence patterns of individual species, having a similar or greater influence than soil temperature, pH and solar radiation. Soil moisture varied considerably over short distances, and this fine-scale heterogeneity may contribute to offsetting the ecological impacts of changes in precipitation for species not limited to extreme soil moisture conditions. In conclusion, soil moisture is a key driver of vegetation properties, both at the species and community level, even in this low-energy system. Soil moisture conditions represent an important mechanism through which changing climatic conditions impact vegetation, and advancing our predictive capability will therefore require a better understanding of how soil moisture mediates the effects of climate change on biota.

  16. Response of Soil Temperature to Climate Change in the CMIP5 Earth System Models

    NASA Astrophysics Data System (ADS)

    Phillips, C. L.; Torn, M. S.; Koven, C. D.

    2014-12-01

    Predictions of soil temperature changes are as critical to policy development and climate change adaptation as predictions of air temperature, but have received comparatively little attention. Soil temperature determines seed germination and growth of wild and agricultural plants, and impacts climate through both geophysical and carbon-cycle feedbacks. The Intergovernmental Panel on Climate Change 5th Assessment Report does not report soil temperature predictions, but focuses instead on surface air temperatures, despite the fact that mean annual soil temperatures and mean surface air temperatures are often different from each other. Here we aim to fill this important knowledge gap by reporting soil temperature and moisture predictions for 15 earth system models (ESMs) that participated in phase 5 of the Coupled Model Intercomparison 5 Project (CMIP5). Under the RCP 4.5 and 8.5 emissions scenarios, soil warming is predicted to almost keep pace with soil air warming, with about 10% less warming in soil than air, globally. The slower warming of soil compared to air is likely related to predictions of soil drying, with drier soils having reduced soil heat capacity and thermal conductivity. Mollisol soils, which are typically regarded as the most productive soil order for cultivating cereal crops, are anticipated to see warming in North America of 3.5 to 5.5 °C at the end of the 21st century (2080-2100) compared to 1986-2005. One impact of soil warming is likely to be an acceleration of germination timing, with the 3°C temperature threshold for wheat germination anticipated to advance by several weeks in Mollisol regions. Furthermore, soil warming at 1 m depth is predicted to be almost equivalent to warming at 1 cm depth in frost-free regions, indicating vulnerability of deep soil carbon pools to destabilization. To assess model performance we compare the models' predictions with observations of damping depth, and offsets between mean annual soil and air temperature

  17. Fate of Acrylamide in Soil and Groundwater Systems: Microbial Degradation

    NASA Astrophysics Data System (ADS)

    Labahn, S.; Moser, D.; Arrowood, T.; Young, M.; Robleto, E.

    2007-12-01

    Acrylamide monomer (AMD), a suspected human neurotoxin and carcinogen, is present as a contaminant (up to 0.05%) in commercial preparations of polyacrylamide (PAM). PAM is currently being evaluated for wide-spread use as a temporary water-delivery canal sealant across the western United States. To better constrain potential risks associated with PAM applications, we examined the capacity of natural canal microorganisms to degrade AMD in laboratory and field experiments. Dilution cultivation and enrichment approaches were employed to determine the abundance of culturable microorganisms in several canal habitats which can utilize AMD as a sole nitrogen source (typically 104-106/mL) and a collection of isolates was developed. AMD-degrading microorganisms in our collection fell within a limited diversity of genera including Arthrobacter, Xanthomonas, and Pseudomonas; with the latter demonstrating highest capacity for degrading AMD under laboratory conditions. One strain of Pseudomonas fluorescens, isolated from Klamath Irrigation District (Klamath Falls, OR) canal sediment, was chosen for further study in part because this species is well-studied and ubiquitous. The potential for microbial AMD degradation was tested under laboratory conditions using this strain in repacked short (15 cm) column tests with two relevant soil types (sand and loam). Subsequently, the capacity of mixed natural microbial populations to degrade AMD was examined using soil cores collected from the Highline Canal (Rocky Ford, CO), and canal water/sediment slurries with spiked (5 ppm AMD) in situ bottle tests. Degradation of the monomer in the repacked column experiments was evaluated using a step input of 5 ppm AMD and the canal columns were tested with a range of AMD concentrations (1-5 ppm) followed by quantification with an HPLC. The repacked soil columns inoculated with P. fluorescens demonstrated 80-100% AMD degradation within 12 hours. Natural microbial communities in fresh canal sediment

  18. Experimental System for Simulating a Natural Soil Temperature Profile during Freeze-thaw Cycles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to better assess the effects of freeze-thaw cycles on soil physical properties, water and contaminant transport, and microbial activity, a simple experimental soil thermal cycling system was developed. The system consisted of an insulated bin containing four cylindrical PVC lysimeters encas...

  19. Development of a desiccated cadaver delivery system to apply entomopathogenic nematodes for control of soil pests

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pentomopathogenic nematodes may be more capable of controlling soil pests when they are harbored by desiccated cadavers. A small-scale system was developed from a modified crop seed planter to effectively deliver desiccated nematode-infected cadavers into the soil. The system mainly consists of a me...

  20. Soil water infiltration affected by topsoil thickness in row crop and switchgrass production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conversion of annual grain crop systems to biofuel production systems can restore soil hydrologic function; however, information on these effects is limited. Hence, the objective of this study was to evaluate the influence of topsoil thickness on water infiltration in claypan soils for grain and swi...

  1. A micro spot injection system for studing the effects of carbonation on fumigant dispersion in soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fumigant transport to deep soils is needed to control plant parasitic nematodes and soil borne pathogens for perennial crops. Using carbonated fumigants and carbon dioxide (CO2)-pressurized fumigant injection systems may achieve this target when compared to conventional fumigation systems pressurize...

  2. DEMONSTRATION BULLETIN: BESCORP SOIL WASHING SYSTEM ALASKAN BATTERY ENTERPRISES SITE - BRICE ENVIRONMENTAL SERVICES CORPORATION

    EPA Science Inventory

    The BESCORP Soil Washing System is an aqueous volume reduction system that utilizes trommel agitation, high-pressure washing, sizing, and density separation to remove lead, lead compounds, and battery casing chips from soil contaminated by broken lead batteries. The basic concept...

  3. Charcoal in the soil and the Earth System

    NASA Astrophysics Data System (ADS)

    Scott, A. C.

    2012-04-01

    Charcoal occurs in the natural environment as either a result of wildfire or volcanic processes. Charcoal is one of a range of pyrolysis products that may be included in the term black carbon. This paper outlines aspects of charcoal formation (both natural and experimental) and briefly considers the taphonomic processes leading to a final assemblage. This is done using examples from recent fires and through experimentation. In particular, it is shown that the temperature of charcoal formation may influence the rate of subsequent decay. This has significance for biochar studies. While charcoal may remain near the place of it's formation and be buried in soils it still may be affected by physical and chemical changes that result in fragmentation and subsequent loss to the soil. Charcoal may also be washed out of the fire site by overland flow particularly if the rain occurs soon after the fire. Charcoal is abundant in many sedimentary rocks deposited in a wide range of environments, from terrestrial to marine. Charcoal has a long fossil record and is found in rock sequences from the late Silurian onwards. Charcoal provides evidence of the deep time history of wildfire. There is an intimate relationship between the history of oxygen in the atmosphere and periods of extensive wildfires. High atmospheric oxygen levels (around 30%) in the late Palaeozoic and Cretaceous had a profound effect on the Earth System. The use of charcoal for plant evolution studies, fire history studies, vegetation studies, anatomical studies, climate and atmospheric studies and the wider importance of charcoal for the Earth and Biological Sciences will be considered (Scott 2010, Glasspool and Scott in press). Charcoal is information-rich but yet is an under-utilized resource.

  4. Fate of synthetic organic chemicals in soil-groundwater systems.

    PubMed

    Pancorbo, O C; Varney, T C

    1986-04-01

    Land disposal of municipal, industrial and agricultural wastes often leads to soil and groundwater contamination with synthetic organic chemicals. In this review, the fate of such organics in soils and the subsurface environment is discussed. In particular, the biodegradation of organic compounds in soils and the subsurface region, as well as the sorption of these compounds to soils is emphasized. Due to the disastrous impact of groundwater contamination on a community and the great cost of restoring a contaminated aquifer, a case is made for concentrating future efforts on isolating potential sources of groundwater contamination and instituting appropriate control measures.

  5. [Modeling the behavior of 137Cs in a soil-plant system after use of ameliorators].

    PubMed

    Spiridonov, S I; Fesenko, S V; Sanzharova, N I

    2001-01-01

    The main processes and mechanisms responsible for 137Cs behaviour in the soil-forest plants system following the application of ameliorants are described. Mathematical models are presented based on the identification of mechanisms governing the physico-chemical and biological processes, a set of which determined the radionuclides uptake by plants. The models parameterization is exemplified by forest soils subjected to radioactive contamination after the Chernobyl accident. Effects of ameliorants and time of their application on 137Cs behaviour in the soil-plant system are assessed. The contribution of soil chemical and biological processes to the decrease in the radionuclide uptake by plants is estimated. PMID:11458650

  6. Ground cover rice production system facilitates soil carbon and nitrogen stocks at regional scale

    NASA Astrophysics Data System (ADS)

    Liu, M.; Dannenmann, M.; Lin, S.; Saiz, G.; Yan, G.; Yao, Z.; Pelster, D.; Tao, H.; Sippel, S.; Tao, Y.; Zhang, Y.; Zheng, X.; Zuo, Q.; Butterbach-Bahl, K.

    2015-02-01

    Rice production is increasingly challenged by irrigation water scarcity, however covering paddy rice soils with films (ground cover rice production system: GCRPS) can significantly reduce water demand as well as overcome temperature limitations at the beginning of the vegetation period resulting in increased grain yields in colder regions of rice production with seasonal water shortages. It has been speculated that the increased soil aeration and temperature under GCRPS may result in losses of soil organic carbon and nitrogen stocks. Here we report on a regional scale experiment, conducted by sampling paired adjacent Paddy and GCRPS fields at 49 representative sites in the Shiyan region, which is typical for many mountainous areas across China. Parameters evaluated included soil C and N stocks, soil physical and chemical properties, potential carbon mineralization rates, fractions of soil organic carbon and stable carbon isotopic composition of plant leaves. Furthermore, root biomass was quantified at maximum tillering stage at one of our paired sites. Against expectations the study showed that: (1) GCRPS significantly increased soil organic C and N stocks 5-20 years following conversion of production systems, (2) there were no differences between GCRPS and Paddy in soil physical and chemical properties for the various soil depths with the exception of soil bulk density, (3) GCRPS had lower mineralization potential for soil organic C compared with Paddy over the incubation period, (4) GCRPS showed lower δ15N in the soils and plant leafs indicating less NH3 volatilization in GCRPS than in Paddy; and (5) GCRPS increased yields and root biomass in all soil layers down to 40 cm depth. Our results suggest that GCRPS is an innovative rice production technique that not only increases yields using less irrigation water, but that it also is environmentally beneficial due to increased soil C and N stocks at regional scale.

  7. Soil Vapor Extraction System Optimization, Transition, and Closure Guidance

    SciTech Connect

    Truex, Michael J.; Becker, Dave; Simon, Michelle A.; Oostrom, Martinus; Rice, Amy K.; Johnson, Christian D.

    2013-02-08

    Soil vapor extraction (SVE) is a prevalent remediation approach for volatile contaminants in the vadose zone. A diminishing rate of contaminant extraction over time is typically observed due to 1) diminishing contaminant mass, and/or 2) slow rates of removal for contamination in low-permeability zones. After a SVE system begins to show indications of diminishing contaminant removal rate, SVE performance needs to be evaluated to determine whether the system should be optimized, terminated, or transitioned to another technology to replace or augment SVE. This guidance specifically addresses the elements of this type of performance assessment. While not specifically presented, the approach and analyses in this guidance could also be applied at the onset of remediation selection for a site as a way to evaluate current or future impacts to groundwater from vadose zone contamination. The guidance presented here builds from existing guidance for SVE design, operation, optimization, and closure from the U.S. Environmental Protection Agency, U.S. Army Corps of Engineers, and the Air Force Center for Engineering and the Environment. The purpose of the material herein is to clarify and focus on the specific actions and decisions related to SVE optimization, transition, and/or closure.

  8. Pneumatic System for Concentration of Micrometer-Size Lunar Soil

    NASA Technical Reports Server (NTRS)

    McKay, David; Cooper, Bonnie

    2012-01-01

    A report describes a size-sorting method to separate and concentrate micrometer- size dust from a broad size range of particles without using sieves, fluids, or other processes that may modify the composition or the surface properties of the dust. The system consists of four processing units connected in series by tubing. Samples of dry particulates such as lunar soil are introduced into the first unit, a fluidized bed. The flow of introduced nitrogen fluidizes the particulates and preferentially moves the finer grain sizes on to the next unit, a flat plate impactor, followed by a cyclone separator, followed by a Nuclepore polycarbonate filter to collect the dust. By varying the gas flow rate and the sizes of various orifices in the system, the size of the final and intermediate particles can be varied to provide the desired products. The dust can be collected from the filter. In addition, electron microscope grids can be placed on the Nuclepore filter for direct sampling followed by electron microscope characterization of the dust without further handling.

  9. Ground cover rice production systems increase soil carbon and nitrogen stocks at regional scale

    NASA Astrophysics Data System (ADS)

    Liu, M.; Dannenmann, M.; Lin, S.; Saiz, G.; Yan, G.; Yao, Z.; Pelster, D. E.; Tao, H.; Sippel, S.; Tao, Y.; Zhang, Y.; Zheng, X.; Zuo, Q.; Butterbach-Bahl, K.

    2015-08-01

    Rice production is increasingly limited by water scarcity. Covering paddy rice soils with films (so-called ground cover rice production system: GCRPS) can significantly reduce water demand as well as overcome temperature limitations at the beginning of the growing season, which results in greater grain yields in relatively cold regions and also in those suffering from seasonal water shortages. However, it has been speculated that both increased soil aeration and temperature under GCRPS result in lower soil organic carbon and nitrogen stocks. Here we report on a regional-scale experiment conducted in Shiyan, a typical rice-producing mountainous area of China. We sampled paired adjacent paddy and GCRPS fields at 49 representative sites. Measured parameters included soil carbon (C) and nitrogen (N) stocks (to 1 m depth), soil physical and chemical properties, δ15N composition of plants and soils, potential C mineralization rates, and soil organic carbon (SOC) fractions at all sampling sites. Root biomass was also quantified at one intensively monitored site. The study showed that: (1) GCRPS increased SOC and N stocks 5-20 years following conversion from traditional paddy systems; (2) there were no differences between GCRPS and paddy systems in soil physical and chemical properties for the various soil depths, with the exception of soil bulk density; (3) GCRPS increased above-ground and root biomass in all soil layers down to a 40 cm depth; (4) δ15N values were lower in soils and plant leaves indicating lower NH3 volatilization losses from GCRPS than in paddy systems; and (5) GCRPS had lower C mineralization potential than that observed in paddy systems over a 200-day incubation period. Our results suggest that GCRPS is an innovative production technique that not only increases rice yields using less irrigation water, but that it also increases SOC and N stocks.

  10. COsmic-ray Soil Moisture Observing System (COSMOS): soil moisture and beyond

    NASA Astrophysics Data System (ADS)

    Zreda, Marek; Shuttleworth, William J.; Zeng, Xubin; Zweck, Chris; Franz, Trenton; Rosolem, Rafael

    2013-04-01

    COSMOS, a project funded by the US National Science Foundation, was designed to measure average soil moisture in the top 10-70 cm of soil over the horizontal footprint of approximately 700 m by measuring cosmic-ray neutrons in air above the ground surface. It is in its fourth, final, year of the feasibility phase in which 60 neutron probes have been installed in the USA to provide continental-scale soil moisture data. The cosmic-ray neutron probe responds to all sources of hydrogen present within the footprint. Therefore, in addition to soil moisture, other pools of hydrogen can be measured; these include atmospheric water vapor, organic matter in soil, water in soil minerals, biomass water (including hydrogen bound in cellulose), and snow on the ground and on the canopy. All these pools of hydrogen form the "total surface moisture" that is measured by COSMOS probes. The first four pools are measured independently (water vapor) or are implicitly included in the probe calibration (water in minerals and organic matter, biomass water). The other two can be separated from one another to produce time series of soil moisture and snow water equivalent. Work is in progress to assimilate neutron data into land-surface models, to produce soil moisture profiles, to validate satellite soil moisture products (the current SMOS mission and the future SMAP mission), to measure temporal variations in biomass, and to measure area-average unsaturated hydraulic properties of soils. Separately, mobile COSMOS probe, called COSMOS rover, is being developed. COSMOS rover can be used to map soil moisture over large areas or along long transects. Cosmic-ray sensing of moisture at the land surface has gained popularity outside of the USA. Approximately 60 probes have been purchased in addition to the 60 probes in the COSMOS project. Funds for additional 80 probes, most of them in Germany, have been secured, and large new proposals will be submitted in the USA and Australia in 2013. These

  11. An integrated soil-crop system model for water and nitrogen management in North China.

    PubMed

    Liang, Hao; Hu, Kelin; Batchelor, William D; Qi, Zhiming; Li, Baoguo

    2016-01-01

    An integrated model WHCNS (soil Water Heat Carbon Nitrogen Simulator) was developed to assess water and nitrogen (N) management in North China. It included five main modules: soil water, soil temperature, soil carbon (C), soil N, and crop growth. The model integrated some features of several widely used crop and soil models, and some modifications were made in order to apply the WHCNS model under the complex conditions of intensive cropping systems in North China. The WHCNS model was evaluated using an open access dataset from the European International Conference on Modeling Soil Water and N Dynamics. WHCNS gave better estimations of soil water and N dynamics, dry matter accumulation and N uptake than 14 other models. The model was tested against data from four experimental sites in North China under various soil, crop, climate, and management practices. Simulated soil water content, soil nitrate concentrations, crop dry matter, leaf area index and grain yields all agreed well with measured values. This study indicates that the WHCNS model can be used to analyze and evaluate the effects of various field management practices on crop yield, fate of N, and water and N use efficiencies in North China. PMID:27181364

  12. An integrated soil-crop system model for water and nitrogen management in North China.

    PubMed

    Liang, Hao; Hu, Kelin; Batchelor, William D; Qi, Zhiming; Li, Baoguo

    2016-05-16

    An integrated model WHCNS (soil Water Heat Carbon Nitrogen Simulator) was developed to assess water and nitrogen (N) management in North China. It included five main modules: soil water, soil temperature, soil carbon (C), soil N, and crop growth. The model integrated some features of several widely used crop and soil models, and some modifications were made in order to apply the WHCNS model under the complex conditions of intensive cropping systems in North China. The WHCNS model was evaluated using an open access dataset from the European International Conference on Modeling Soil Water and N Dynamics. WHCNS gave better estimations of soil water and N dynamics, dry matter accumulation and N uptake than 14 other models. The model was tested against data from four experimental sites in North China under various soil, crop, climate, and management practices. Simulated soil water content, soil nitrate concentrations, crop dry matter, leaf area index and grain yields all agreed well with measured values. This study indicates that the WHCNS model can be used to analyze and evaluate the effects of various field management practices on crop yield, fate of N, and water and N use efficiencies in North China.

  13. An integrated soil-crop system model for water and nitrogen management in North China

    PubMed Central

    Liang, Hao; Hu, Kelin; Batchelor, William D.; Qi, Zhiming; Li, Baoguo

    2016-01-01

    An integrated model WHCNS (soil Water Heat Carbon Nitrogen Simulator) was developed to assess water and nitrogen (N) management in North China. It included five main modules: soil water, soil temperature, soil carbon (C), soil N, and crop growth. The model integrated some features of several widely used crop and soil models, and some modifications were made in order to apply the WHCNS model under the complex conditions of intensive cropping systems in North China. The WHCNS model was evaluated using an open access dataset from the European International Conference on Modeling Soil Water and N Dynamics. WHCNS gave better estimations of soil water and N dynamics, dry matter accumulation and N uptake than 14 other models. The model was tested against data from four experimental sites in North China under various soil, crop, climate, and management practices. Simulated soil water content, soil nitrate concentrations, crop dry matter, leaf area index and grain yields all agreed well with measured values. This study indicates that the WHCNS model can be used to analyze and evaluate the effects of various field management practices on crop yield, fate of N, and water and N use efficiencies in North China. PMID:27181364

  14. Dechlorination of DDT, DDD and DDE in soil (slurry) phase using magnesium/palladium system.

    PubMed

    Gautam, Sumit Kumar; Suresh, Sumathi

    2006-12-01

    Mg0/Pd4+ was able to dechlorinate >99% of extractable DDT (initial concentration of 10 mg DDT kg(-1) of soil) and >90% of extractable DDT (initial concentration of 50 mg DDT kg(-1) of soil) in soil slurry. Mg0/Pd4+ was also found to be effective in dechlorinating of 50 mg kg(-1) DDD and DDE, in soil aged for varying time periods. GC-MS analyses revealed the formation of 1,1-diphenylethane as an end product from DDT, DDE and DDD. To the best of our knowledge this is the first report describing the application Mg0/Pd4+ system for remediation of DDT, DDD and DDE contaminated soil. We conclude that reductive dechlorination reaction catalyzed by Mg0/Pd4+ may be a promising system to remediate soil contaminated with DDT and its dechlorinated products such as DDD and DDE.

  15. Ecological optimality in water-limited natural soil-vegetation systems. I - Theory and hypothesis

    NASA Technical Reports Server (NTRS)

    Eagleson, P. S.

    1982-01-01

    The solution space of an approximate statistical-dynamic model of the average annual water balance is explored with respect to the hydrologic parameters of both soil and vegetation. Within the accuracy of this model it is shown that water-limited natural vegetation systems are in stable equilibrium with their climatic and pedologic environments when the canopy density and species act to minimize average water demand stress. Theory shows a climatic limit to this equilibrium above which it is hypothesized that ecological pressure is toward maximization of biomass productivity. It is further hypothesized that natural soil-vegetation systems will develop gradually and synergistically, through vegetation-induced changes in soil structure, toward a set of hydraulic soil properties for which the minimum stress canopy density of a given species is maximum in a given climate. Using these hypotheses, only the soil effective porosity need be known to determine the optimum soil and vegetation parameters in a given climate.

  16. Toward Soil Spatial Information Systems (SSIS) for global modeling and ecosystem management

    NASA Technical Reports Server (NTRS)

    Baumgardner, Marion F.

    1995-01-01

    The general objective is to conduct research to contribute toward the realization of a world soils and terrain (SOTER) database, which can stand alone or be incorporated into a more complete and comprehensive natural resources digital information system. The following specific objectives are focussed on: (1) to conduct research related to (a) translation and correlation of different soil classification systems to the SOTER database legend and (b) the inferfacing of disparate data sets in support of the SOTER Project; (2) to examine the potential use of AVHRR (Advanced Very High Resolution Radiometer) data for delineating meaningful soils and terrain boundaries for small scale soil survey (range of scale: 1:250,000 to 1:1,000,000) and terrestrial ecosystem assessment and monitoring; and (3) to determine the potential use of high dimensional spectral data (220 reflectance bands with 10 m spatial resolution) for delineating meaningful soils boundaries and conditions for the purpose of detailed soil survey and land management.

  17. Non-stationarity of electrical resistivity and soil moisture relationship in heterogeneous soil system: a case study

    NASA Astrophysics Data System (ADS)

    Michot, D.; Thomas, Z.; Adam, I.

    2015-09-01

    Root uptake is the most decisive key in water transfer involving soil and vegetation. It depends on water availability which can be evaluated by punctual measurements. Additionally, surface geophysical methods such as Electrical Resistivity Tomography (ERT) provide larger spatial scales. This paper focuses on investigating temporal and spatial soil moisture changes, along a toposequence crossed by a hedgerow, using ERT and punctual measurements. 10 ERT were performed over the studied period for a 28 m long transect and compared to matric potential and groundwater level measurements. Soil Volumetric Water Content (VWC) was predicted using two methods (i) from ER using Waxman and Smits model (ii) and from matric potential using experimental retention curve fitted by Van Genuchten model. Probability Density Functions (Pdfs) of our set of data show that the largest change, in mean values of ER as well as matric potential, was observed in the topsoil layer. We then analyzed the consistency between ER and punctual measurements in this layer by extracting the arrays in the junction between ER grids and punctual measurements. Pdfs of ER maps at each monitoring time (from T01 to T10) were also calculated to select the more contrasted distributions corresponding to the wettest (T06) and driest states (T10). Results of ER were consistent with matric potential measurements with two different behaviors for locations inside and outside the root zone. A strong correlation (r = 0.9) between VWC values from Waxman and Smits model and those obtained from retention curve was observed outside the root zone. The heterogeneous soil system inside the root zone shows a different pattern in this relationship. The shift in the relationship between ER and soil moisture for the locations outside and inside the root zone highlights the non-stationarity in heterogeneous soil system. Such systems were actually related to the high hedgerow root density and also to a particular topographical

  18. Trace element biogeochemistry in the soil-water-plant system of a temperate agricultural soil amended with different biochars.

    PubMed

    Kloss, Stefanie; Zehetner, Franz; Buecker, Jannis; Oburger, Eva; Wenzel, Walter W; Enders, Akio; Lehmann, Johannes; Soja, Gerhard

    2015-03-01

    Various biochar (BC) types have been investigated as soil amendment; however, information on their effects on trace element (TE) biogeochemistry in the soil-water-plant system is still scarce. In the present study, we determined aqua-regia (AR) and water-extractable TEs of four BC types (woodchips (WC), wheat straw (WS), vineyard pruning (VP), pyrolyzed at 525 °C, of which VP was also pyrolyzed at 400 °C) and studied their effects on TE concentrations in leachates and mustard (Sinapis alba L.) tissue in a greenhouse pot experiment. We used an acidic, sandy agricultural soil and a BC application rate of 3% (w/w). Our results show that contents and extractability of TEs in the BCs and effectuated changes of TE biogeochemistry in the soil-water-plant system strongly varied among the different BC types. High AR-digestable Cu was found in VP and high B contents in WC. WS had the highest impact on TEs in leachates showing increased concentrations of As, Cd, Mo, and Se, whereas WC application resulted in enhanced leaching of B. All BC types increased Mo and decreased Cu concentrations in the plant tissue; however, they showed diverging effects on Cu in the leachates with decreased concentrations for WC and WS, but increased concentrations for both VPs. Our results demonstrate that BCs may release TEs into the soil-water-plant system. A BC-induced liming effect in acidic soils may lead to decreased plant uptake of cationic TEs, including Pb and Cd, but may enhance the mobility of anionic TEs like Mo and As. We also found that BCs with high salt contents (e.g., straw-based BCs) may lead to increased mobility of both anionic and cationic TEs in the short term. PMID:25315931

  19. Trace element biogeochemistry in the soil-water-plant system of a temperate agricultural soil amended with different biochars.

    PubMed

    Kloss, Stefanie; Zehetner, Franz; Buecker, Jannis; Oburger, Eva; Wenzel, Walter W; Enders, Akio; Lehmann, Johannes; Soja, Gerhard

    2015-03-01

    Various biochar (BC) types have been investigated as soil amendment; however, information on their effects on trace element (TE) biogeochemistry in the soil-water-plant system is still scarce. In the present study, we determined aqua-regia (AR) and water-extractable TEs of four BC types (woodchips (WC), wheat straw (WS), vineyard pruning (VP), pyrolyzed at 525 °C, of which VP was also pyrolyzed at 400 °C) and studied their effects on TE concentrations in leachates and mustard (Sinapis alba L.) tissue in a greenhouse pot experiment. We used an acidic, sandy agricultural soil and a BC application rate of 3% (w/w). Our results show that contents and extractability of TEs in the BCs and effectuated changes of TE biogeochemistry in the soil-water-plant system strongly varied among the different BC types. High AR-digestable Cu was found in VP and high B contents in WC. WS had the highest impact on TEs in leachates showing increased concentrations of As, Cd, Mo, and Se, whereas WC application resulted in enhanced leaching of B. All BC types increased Mo and decreased Cu concentrations in the plant tissue; however, they showed diverging effects on Cu in the leachates with decreased concentrations for WC and WS, but increased concentrations for both VPs. Our results demonstrate that BCs may release TEs into the soil-water-plant system. A BC-induced liming effect in acidic soils may lead to decreased plant uptake of cationic TEs, including Pb and Cd, but may enhance the mobility of anionic TEs like Mo and As. We also found that BCs with high salt contents (e.g., straw-based BCs) may lead to increased mobility of both anionic and cationic TEs in the short term.

  20. System of extraction of volatiles from soil using microwave processes

    NASA Technical Reports Server (NTRS)

    Ethridge, Edwin C. (Inventor); Kaukler, William F. (Inventor)

    2013-01-01

    A device for the extraction and collection of volatiles from soil or planetary regolith. The device utilizes core drilled holes to gain access to underlying volatiles below the surface. Microwave energy beamed into the holes penetrates through the soil or regolith to heat it, and thereby produces vapor by sublimation. The device confines and transports volatiles to a cold trap for collection.

  1. Understanding plant root system influences on soil strength and stability

    NASA Astrophysics Data System (ADS)

    Bengough, A. Glyn; Brown, Jennifer L.; Loades, Kenneth W.; Knappett, Jonathan A.; Meijer, Gertjan; Nicoll, Bruce

    2016-04-01

    Keywords: root growth, soil reinforcement, tensile strength Plant roots modify and reinforce the soil matrix, stabilising it against erosion and shallow landslides. Roots mechanically bind the soil particles together and modify the soil hydrology via water uptake, creation of biopores, and modification of the soil water-release characteristic. Key to understanding the mechanical reinforcement of soil by roots is the relation between root strength and root diameter measured for roots in any given soil horizon. Thin roots have frequently been measured to have a greater tensile strength than thick roots, but their strength is also often much more variable. We consider the factors influencing this strength-diameter relationship, considering relations between root tensile strength and root dry density, root water content, root age, and root turnover in several woody and non-woody species. The role of possible experimental artefacts and measurement techniques will be considered. Tensile strength increased generally with root age and decreased with thermal time after excision as a result of root decomposition. Single factors alone do not appear to explain the strength-diameter relationship, and both strength/stiffness and dry density may vary between different layers of tissue within a single root. Results will be discussed to consider how we can achieve a more comprehensive understanding of the variation in root biomechanical properties, and its consequences for soil reinforcement. Acknowledgements: The James Hutton Institute receives funding from the Scottish Government. AGB and JAK acknowledge part funding from EPSRC (EP/M020355/1).

  2. Regional estimation of soil C stocks and CO2 emissions as influenced by cropping systems and soil type

    NASA Astrophysics Data System (ADS)

    Farina, Roberta; Marchetti, Alessandro; Di Bene, Claudia

    2015-04-01

    Soil organic matter (SOM) is of crucial importance for agricultural soil quality and fertility. At global level soil contains about three times the carbon stored in the vegetation and about twice that present in the atmosphere. Soil could act as source and sink of carbon, influencing the balance of CO2 concentration and consequently the global climate. The sink/source ratio depends on many factors that encompass climate, soil characteristics and different land management practices. Thus, the relatively large gross exchange of GHGs between atmosphere and soils and the significant stocks of carbon in soils, may have significant impact on climate and on soil quality. To quantify the dynamics of C induced by land cover change and the spatial and temporal dynamics of C sources and sinks at regional and, potentially, at national and global scales, we propose a methodology, based on a bio-physical model combined with a spatial explicit database to estimate C stock changes and emissions/removals. The study has been conducted in a pilot region in Italy (Apulia, Foggia province), considering the typical cropping systems of the area, namely rainfed cereals, tomato, vineyard and olives. For this purpose, the model RothC10N (Farina et al., 2013), that simulates soil C dynamics, has been modified to work directly in batch using data of climate, soil (over 290 georeferenced soil profiles), annual agriculture land use (1200 observations) The C inputs from crops have been estimated using statistics and data from literature. The model was run to equilibrium for each point of soil, in order to make all the data homogeneous in terms of time. The obtained data were interpolate with geostatisical procedures, obtaining a set of 30x30 km grid with the initial soil C. The new layer produced, together with soil and land use layers, were used for a long-term run (12 years). Results showed that olive groves and vineyards were able to stock a considerable amount of C (from 0.4 to 1.5 t ha-1 y

  3. Metals in soils of erosional systems in forest zone

    NASA Astrophysics Data System (ADS)

    Samonova, Olga; Aseyeva, Elena

    2013-04-01

    Basin approach is attracting increasing attention in modern geosciences because of its significance for pollution monitoring both at a large (regional) and small catchment (local) scale. The implication of this approach in geochemical studies faces many difficulties which arise mainly from methodological aspects. This paper presents a case study dealing with geochemistry of two small erosional systems - a gully and an aged balka - located in the southern taiga zone of European Russia (the Protva river basin). The erosional forms have been considered as integrated systems comprising slopes, bottoms, detrital fans as well as surrounding areas as sources of solid matter. We used chemical composition of topsoil (total concentrations of Ti, Zr, Mn, Co, Zn, Cu, Pb, Cr, V, Ni, Sn, Sr, Ba and concentrations of the acid-extractable Fe, Mn, Co, Zn, Cu, Pb, Cr, Ni) to explore the role of granulometry, pH and transport processes in geochemical differentiation of the systems. Spatial variations in topsoil granulometry across surrounding areas, slopes and bottoms of the studied systems indicate a removal of finer material through the gully system and accumulation of silt and clay-size particles within the balka. The statistical analysis has proved that the behavior of the majority of the metals in the studied systems is controlled by distribution of medium silt and clay fractions (in the gully) and by coarse and medium silt (in the balka). Total concentrations of Ti, Mn, V, Zn, Zr and the abundances of acid-extractible forms of all studied metals except of Ni are higher is the soils of balka. The young gully system operate as a transit system: total concentrations of Mn, Ti, Zr, Ba, Sr, V, Pb (as well as Zn, Cr) and the abundances of acid-extractible compounds of Mn, Co, Pb (as well as Cu, Zn, Ni) are decreasing from the gully's interfluve and slopes to its bottom. The balka system has the same trends for Mn, Ti, Ba, Co, Cu and mobile compounds of Pb, Co, Ni. However for some

  4. Can subterranean cave systems affect soil CO2 fluxes?

    NASA Astrophysics Data System (ADS)

    Krajnc, Bor; Ferlan, Mitja; Ogrinc, Nives

    2015-04-01

    Main factors affecting soil CO2 fluxes in most ecosystems are soil temperature and soil moisture. Nevertheless occasionally high soil CO2 fluxes were observed at carst areas, which could result from ventilation of subterranean cavities (Ferlan et al., 2011). The aim of this work was to determine the influence of cave ventilation to soil CO2 fluxes. Research was done in a dead-end passage of Postojna cave (Pisani rov) and on the surface area above the passage (Velika Jeršanova dolina) in south-western Slovenia. Inside the cave we measured CO2 concentrations, its carbon (13C) stable isotope composition, 222Rn activity concentrations, temperatures and air pressure. At the surface we had chosen two sampling plots; test plot above the cave and control. At both plots we measured soil CO2 fluxes with automatic chambers, CO2 concentrations, temperatures and carbon stable isotope composition of soil air at three different depths (0.2 m, 0.5 m and 0.8 m) and different meteorological parameters such as: air temperature, air pressure, wind speed an precipitation. To detect the cave influence, we compared two surface CO2 flux measurements with air temperatures and changes of CO2 concentrations in the cave atmosphere. Our results on CO2 concentrations in the gallery of the cave indicated that the ventilation of this particular gallery also depends on outside air temperatures. Outside temperature increased and corresponded to higher CO2 concentrations, whereas at lower temperatures (T < 9 oC) cave started to ventilate and exhaled CO2 reach air through unknown fissures and cracks. At the control plot the soil CO2 fluxes were in a good correlation with soil temperatures (r = 0.789, p =0.01), where greater soil temperatures correspond to greater soil CO2 fluxes. Soil CO2 fluxes at the plot above the cave did not show statistically significant correlations with soil temperatures or soil moisture indicating that other factors possibly cave ventilation could influence it. References

  5. Feasibility for application of soil bioengineering techniques to natural wastewater treatment systems. Master's thesis

    SciTech Connect

    Cox, A.J.

    1992-12-01

    This report examines the general feasibility for application of Soil Bioengineering techniques in construction, operation, and management of natural wastewater treatment systems. Soil Bioengineering is an applied science that combines structural, biological, and ecological concepts to construct living structures for erosion, sediment, and flood control (Sotir and Gray, 1989). Using live plant parts as major structural components to reinforce the soil mantle, Soil Bioengineering offers natural and effective solutions to land instability problems along streams and rivers, transportation and utilities transmission corridors, and in forest and wetlands sites. Natural treatment systems are wastewater treatment processes which use the soil-water-plant matrix as a 'natural reactor' for physically, chemically, and biologically stabilizing applied wastes. Recognized natural treatment systems currently include constructed and natural wetlands, aquatic plant systems(aquaculture), wastewater stabilization ponds, and land application of wastes, termed 'land treatment'.

  6. Organic fertilization for soil improvement in a vegetable cropping system

    NASA Astrophysics Data System (ADS)

    Verhaeghe, Micheline; De Rocker, Erwin; De Reycke, Luc

    2016-04-01

    Vegetable Research Centre East-Flanders Karreweg 6, 9770 Kruishoutem, Belgium A long term trial for soil improvement by organic fertilization was carried out in Kruishoutem from 2001 till 2010 in a vegetable rotation (carrots - leek - lettuce (2/year) - cauliflower (2/year) - leek - carrots - lettuce (2/year) - cauliflower (2/year) - leek and spinach). The trial compared yearly applications of 30 m²/ha of three types of compost (green compost, vfg-compost and spent mushroom compost) with an untreated object which did not receive any organic fertilization during the trial timescale. The organic fertilization was applied shortly before the cropping season. Looking at the soil quality, effects of organic fertilization manifest rather slow. The first four years after the beginning of the trial, no increase in carbon content of the soil is detectable yet. Although, mineralization of the soil has increased. The effect on the mineralization is mainly visible in crops with a lower N uptake (e.g. carrots) leading to a higher nitrate residue after harvest. Effects on soil structure and compaction occur rather slowly although, during the first two cropping seasons compost applications increase the water retention capacity of the soil. Compost increases the pH of the soil from the first year on till the end of the trial in 2010. Thus, organic fertilization impedes acidification in light sandy soils. Also soil fertility benefits from compost by an increase in K-, Ca- and Mg- content in the soil from the second year on. After 10 years of organic fertilization, yield and quality of spinach were increased significantly (p<0.05) compared to the untreated object. Also leek (2002 and 2009) and lettuce (2003 and 2007) benefit from organic fertilization.

  7. Changes in soil lignin by the conversion of forest to silvopastoral systems in hill-lands of Appalachia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Establishment of silvopastoral systems in Appalachia has potential to increase farm income. Required fertilization and liming for the silvopastoral systems modifies soil chemical properties, including formation and stabilization of soil organic matter (SOM) though the impact is unknown. Lignin is ...

  8. Interactions of Aqueous U(VI) with Soil Minerals in Slightly Alkaline Natural Systems

    SciTech Connect

    Qafoku, Nik; Icenhower, Jonathan P.

    2008-12-01

    Uranium (U) is a common contaminant at numerous surface and subsurface sites around the world. This paper covers some important aspects of the aqueous hexavalent uranium [U(VI)] interactions with soil minerals that are present in contaminated soils and sediments. The retention of U via interactions with soil minerals has significant consequences for the prediction of its short – and long – term behavior in soils and geological systems. Studies of the nature and type of these interactions have provided the necessary evidence for assessing the geochemical behavior of U in natural systems under different physical, biogeochemical, hydrological, and reducing or oxidizing conditions. Over the last 20 years, aqueous U(VI):solid phase interactions have been studied by geochemists, soil chemists, soil mineralogists and soil microbiologists, and the progress in some areas is remarkable. Although a mechanistic description and understanding of the complex interactions involving U and soil minerals of natural systems is currently impossible, results from carefully designed and executed experiments with these materials have improved our understanding of the heterogeneous system’s behavior and U contaminant mobility and transport. There are, however, areas that need further exploration and study. Numerous research publications were reviewed in this paper to present important findings coming out of the research, to reveal the current level of the understanding of the U(VI) interactions with soil minerals, and to provide ideas for future needs and research directions.

  9. Distribution patterns of phthalic acid esters in soil particle-size fractions determine biouptake in soil-cereal crop systems

    PubMed Central

    Tan, Wenbing; Zhang, Yuan; He, Xiaosong; Xi, Beidou; Gao, Rutai; Mao, Xuhui; Huang, Caihong; Zhang, Hui; Li, Dan; Liang, Qiong; Cui, Dongyu; Alshawabkeh, Akram N.

    2016-01-01

    The use of wastewater irrigation for food crops can lead to presence of bioavailable phthalic acid esters (PAEs) in soils, which increase the potential for human exposure and adverse carcinogenic and non-cancer health effects. This study presents the first investigation of the occurrence and distribution of PAEs in a maize-wheat double-cropping system in a wastewater-irrigated area in the North China Plain. PAE levels in maize and wheat were found to be mainly attributed to PAE stores in soil coarse (250–2000 μm) and fine sand (53–250 μm) fractions. Soil particle-size fractions with higher bioavailability (i.e., coarse and fine sands) showed greater influence on PAE congener bioconcentration factors compared to PAE molecular structures for both maize and wheat tissues. More PAEs were allocated to maize and wheat grains with increased soil PAE storages from wastewater irrigation. Additional findings showed that levels of both non-cancer and carcinogenic risk for PAE congeners in wheat were higher than those in maize, suggesting that wheat food security should be prioritized. In conclusion, increased soil PAE concentrations specifically in maize and wheat grains indicate that wastewater irrigation can pose a contamination threat to food resources. PMID:27555553

  10. Distribution patterns of phthalic acid esters in soil particle-size fractions determine biouptake in soil-cereal crop systems

    NASA Astrophysics Data System (ADS)

    Tan, Wenbing; Zhang, Yuan; He, Xiaosong; Xi, Beidou; Gao, Rutai; Mao, Xuhui; Huang, Caihong; Zhang, Hui; Li, Dan; Liang, Qiong; Cui, Dongyu; Alshawabkeh, Akram N.

    2016-08-01

    The use of wastewater irrigation for food crops can lead to presence of bioavailable phthalic acid esters (PAEs) in soils, which increase the potential for human exposure and adverse carcinogenic and non-cancer health effects. This study presents the first investigation of the occurrence and distribution of PAEs in a maize-wheat double-cropping system in a wastewater-irrigated area in the North China Plain. PAE levels in maize and wheat were found to be mainly attributed to PAE stores in soil coarse (250–2000 μm) and fine sand (53–250 μm) fractions. Soil particle-size fractions with higher bioavailability (i.e., coarse and fine sands) showed greater influence on PAE congener bioconcentration factors compared to PAE molecular structures for both maize and wheat tissues. More PAEs were allocated to maize and wheat grains with increased soil PAE storages from wastewater irrigation. Additional findings showed that levels of both non-cancer and carcinogenic risk for PAE congeners in wheat were higher than those in maize, suggesting that wheat food security should be prioritized. In conclusion, increased soil PAE concentrations specifically in maize and wheat grains indicate that wastewater irrigation can pose a contamination threat to food resources.

  11. Modeling of Water Flow Processes in the Soil-Plant-Atmosphere System: The Soil-Tree-Atmosphere Continuum Model

    NASA Astrophysics Data System (ADS)

    Massoud, E. C.; Vrugt, J. A.

    2015-12-01

    Trees and forests play a key role in controlling the water and energy balance at the land-air surface. This study reports on the calibration of an integrated soil-tree-atmosphere continuum (STAC) model using Bayesian inference with the DREAM algorithm and temporal observations of soil moisture content, matric head, sap flux, and leaf water potential from the King's River Experimental Watershed (KREW) in the southern Sierra Nevada mountain range in California. Water flow through the coupled system is described using the Richards' equation with both the soil and tree modeled as a porous medium with nonlinear soil and tree water relationships. Most of the model parameters appear to be reasonably well defined by calibration against the observed data. The posterior mean simulation reproduces the observed soil and tree data quite accurately, but a systematic mismatch is observed between early afternoon measured and simulated sap fluxes. We will show how this points to a structural error in the STAC-model and suggest and test an alternative hypothesis for root water uptake that alleviates this problem.

  12. Distribution patterns of phthalic acid esters in soil particle-size fractions determine biouptake in soil-cereal crop systems.

    PubMed

    Tan, Wenbing; Zhang, Yuan; He, Xiaosong; Xi, Beidou; Gao, Rutai; Mao, Xuhui; Huang, Caihong; Zhang, Hui; Li, Dan; Liang, Qiong; Cui, Dongyu; Alshawabkeh, Akram N

    2016-01-01

    The use of wastewater irrigation for food crops can lead to presence of bioavailable phthalic acid esters (PAEs) in soils, which increase the potential for human exposure and adverse carcinogenic and non-cancer health effects. This study presents the first investigation of the occurrence and distribution of PAEs in a maize-wheat double-cropping system in a wastewater-irrigated area in the North China Plain. PAE levels in maize and wheat were found to be mainly attributed to PAE stores in soil coarse (250-2000 μm) and fine sand (53-250 μm) fractions. Soil particle-size fractions with higher bioavailability (i.e., coarse and fine sands) showed greater influence on PAE congener bioconcentration factors compared to PAE molecular structures for both maize and wheat tissues. More PAEs were allocated to maize and wheat grains with increased soil PAE storages from wastewater irrigation. Additional findings showed that levels of both non-cancer and carcinogenic risk for PAE congeners in wheat were higher than those in maize, suggesting that wheat food security should be prioritized. In conclusion, increased soil PAE concentrations specifically in maize and wheat grains indicate that wastewater irrigation can pose a contamination threat to food resources.

  13. Distribution patterns of phthalic acid esters in soil particle-size fractions determine biouptake in soil-cereal crop systems.

    PubMed

    Tan, Wenbing; Zhang, Yuan; He, Xiaosong; Xi, Beidou; Gao, Rutai; Mao, Xuhui; Huang, Caihong; Zhang, Hui; Li, Dan; Liang, Qiong; Cui, Dongyu; Alshawabkeh, Akram N

    2016-01-01

    The use of wastewater irrigation for food crops can lead to presence of bioavailable phthalic acid esters (PAEs) in soils, which increase the potential for human exposure and adverse carcinogenic and non-cancer health effects. This study presents the first investigation of the occurrence and distribution of PAEs in a maize-wheat double-cropping system in a wastewater-irrigated area in the North China Plain. PAE levels in maize and wheat were found to be mainly attributed to PAE stores in soil coarse (250-2000 μm) and fine sand (53-250 μm) fractions. Soil particle-size fractions with higher bioavailability (i.e., coarse and fine sands) showed greater influence on PAE congener bioconcentration factors compared to PAE molecular structures for both maize and wheat tissues. More PAEs were allocated to maize and wheat grains with increased soil PAE storages from wastewater irrigation. Additional findings showed that levels of both non-cancer and carcinogenic risk for PAE congeners in wheat were higher than those in maize, suggesting that wheat food security should be prioritized. In conclusion, increased soil PAE concentrations specifically in maize and wheat grains indicate that wastewater irrigation can pose a contamination threat to food resources. PMID:27555553

  14. Soil fate of agricultural fumigants in raised-bed, plasticulture systems in the southeastern United States.

    PubMed

    Chellemi, Dan O; Ajwa, Husein A; Sullivan, David A; Alessandro, Rocco; Gilreath, James P; Yates, Scott R

    2011-01-01

    Soil concentrations and degradation rates of methyl isothio-cyanate (MITC), chloropicrin (CP), 1,3-dichloropropene (1,3-D), and dimethyl disulfide (DMDS) were determined under fumigant application scenarios representative of commercial raised bed, plastic mulched vegetable production systems. Five days after application, 1,3-D, MITC, and CP were detected at concentrations up to 3.52, 0.72, and 2.45 μg cm, respectively, in the soil atmosphere when applications were made in uniformly compacted soils with a water content >200% of field capacity and covered by a virtually impermeable or metalized film. By contrast, DMDS, MITC, and CP concentrations in the soil atmosphere were 0.81, 0.02, and 0.05 μg cm, respectively, 5 d after application in soil containing undecomposed plant residue, numerous large (>3 mm) clods, and water content below field capacity and covered by low-density polyethylene. Ranked in order of impact on the persistence of fumigants in soil were soil water content (moisture), soil tilth (the physical condition of soil as related to its fitness as a planting bed), the type of plastic film used to cover fumigated beds, and soil texture. Fumigants were readily detected 13 d after application when applied in uniformly compacted soils with water contents >200% of capacity and covered by a virtually impermeable or metalized film. By contrast, 1,3-D and MITC had dissipated 5 d after application in soils with numerous large (>3 mm) clods and water contents below field capacity that were covered by low-density polyethylene. Soil degradation of CP, DMDS, and MITC were primarily attributed to biological mechanisms, whereas degradation of 1,3-D was attributed principally to abiotic factors. This study demonstrates improved soil retention of agricultural fumigants in application scenarios representative of good agricultural practices.

  15. A Tale of Four Stories: Soil Ecology, Theory, Evolution and the Publication System

    PubMed Central

    Barot, Sébastien; Blouin, Manuel; Fontaine, Sébastien; Jouquet, Pascal; Lata, Jean-Christophe; Mathieu, Jérôme

    2007-01-01

    Background Soil ecology has produced a huge corpus of results on relations between soil organisms, ecosystem processes controlled by these organisms and links between belowground and aboveground processes. However, some soil scientists think that soil ecology is short of modelling and evolutionary approaches and has developed too independently from general ecology. We have tested quantitatively these hypotheses through a bibliographic study (about 23000 articles) comparing soil ecology journals, generalist ecology journals, evolutionary ecology journals and theoretical ecology journals. Findings We have shown that soil ecology is not well represented in generalist ecology journals and that soil ecologists poorly use modelling and evolutionary approaches. Moreover, the articles published by a typical soil ecology journal (Soil Biology and Biochemistry) are cited by and cite low percentages of articles published in generalist ecology journals, evolutionary ecology journals and theoretical ecology journals. Conclusion This confirms our hypotheses and suggests that soil ecology would benefit from an effort towards modelling and evolutionary approaches. This effort should promote the building of a general conceptual framework for soil ecology and bridges between soil ecology and general ecology. We give some historical reasons for the parsimonious use of modelling and evolutionary approaches by soil ecologists. We finally suggest that a publication system that classifies journals according to their Impact Factors and their level of generality is probably inadequate to integrate “particularity” (empirical observations) and “generality” (general theories), which is the goal of all natural sciences. Such a system might also be particularly detrimental to the development of a science such as ecology that is intrinsically multidisciplinary. PMID:18043755

  16. The controlling of landfill leachate evapotranspiration from soil-plant systems with willow: Salix amygdalina L.

    PubMed

    Białowiec, Andrzej; Wojnowska-Baryła, Irena; Hasso-Agopsowicz, Marek

    2007-02-01

    The use of willows (Salix amygdalina L) to manage landfill leachate disposal is an effective and cost-effective method due to the high transpiration ability of the willow plants. A 2-year lysimetric experiment was performed to determine an optimum leachate hydraulic loading rate to achieve high evapotranspiration but exert no harmful influence on the plants. The evapotranspiration rate of a soil-plant system planted with the willow was 1.28-5.12-fold higher than the rate measured on a soil surface lacking vegetation, suggesting that soil-willow systems with high volatilization rates are a viable landfill leachate treatment method. Of the soil-willow systems, the one with willow growing on sand amended with sewage sludge soil at an hydraulic loading rate of 1 mm day(-1) performed best, with evapotranspiration ranging from 2.25 to 3.02 mm day(-1) and a biomass yield of 8.0-9.85 Mg dry matter ha(-1). The organic fraction of the soil increased as much as 2.5% of dry matter, due to the sewage sludge input, which exerted a positive effect on the biomass yield as well as on transpiration and evaporation. It was observed that the plants in the sand-and-sewage sludge soil systems displayed higher resistance to toxic effects from the applied landfill leachate relative to plants in the sand-soil systems.

  17. The controlling of landfill leachate evapotranspiration from soil-plant systems with willow: Salix amygdalina L.

    PubMed

    Białowiec, Andrzej; Wojnowska-Baryła, Irena; Hasso-Agopsowicz, Marek

    2007-02-01

    The use of willows (Salix amygdalina L) to manage landfill leachate disposal is an effective and cost-effective method due to the high transpiration ability of the willow plants. A 2-year lysimetric experiment was performed to determine an optimum leachate hydraulic loading rate to achieve high evapotranspiration but exert no harmful influence on the plants. The evapotranspiration rate of a soil-plant system planted with the willow was 1.28-5.12-fold higher than the rate measured on a soil surface lacking vegetation, suggesting that soil-willow systems with high volatilization rates are a viable landfill leachate treatment method. Of the soil-willow systems, the one with willow growing on sand amended with sewage sludge soil at an hydraulic loading rate of 1 mm day(-1) performed best, with evapotranspiration ranging from 2.25 to 3.02 mm day(-1) and a biomass yield of 8.0-9.85 Mg dry matter ha(-1). The organic fraction of the soil increased as much as 2.5% of dry matter, due to the sewage sludge input, which exerted a positive effect on the biomass yield as well as on transpiration and evaporation. It was observed that the plants in the sand-and-sewage sludge soil systems displayed higher resistance to toxic effects from the applied landfill leachate relative to plants in the sand-soil systems. PMID:17346008

  18. Soil conditions and cereal root system architecture: review and considerations for linking Darwin and Weaver.

    PubMed

    Rich, Sarah M; Watt, Michelle

    2013-03-01

    Charles Darwin founded root system architecture research in 1880 when he described a root bending with gravity. Curving, elongating, and branching are the three cellular processes in roots that underlie root architecture. Together they determine the distribution of roots through soil and time, and hence the plants' access to water and nutrients, and anchorage. Most knowledge of these cellular processes comes from seedlings of the model dicotyledon, Arabidopsis, grown in soil-less conditions with single treatments. Root systems in the field, however, face multiple stimuli that interact with the plant genetics to result in the root system architecture. Here we review how soil conditions influence root system architecture; focusing on cereals. Cereals provide half of human calories, and their root systems differ from those of dicotyledons. We find that few controlled-environment studies combine more than one soil stimulus and, those that do, highlight the complexity of responses. Most studies are conducted on seedling roots; those on adult roots generally show low correlations to seedling studies. Few field studies report root and soil conditions. Until technologies are available to track root architecture in the field, soil analyses combined with knowledge of the effects of factors on elongation and gravitropism could be ranked to better predict the interaction between genetics and environment (G×E) for a given crop. Understanding how soil conditions regulate root architecture can be effectively used to design soil management and plant genetics that best exploit synergies from G×E of roots.

  19. [Effects of mixed chelators on the leaching of cadmium in contaminated soils under intercropping system].

    PubMed

    Zhou, Jian-Li; Wu, Qi-Tang; Wei, Ze-Bin; Guo, Xiao-Fang; Qiu, Jin-Rong; Huang, Zhu-Jian

    2011-11-01

    In order to elucidate the influence of chelators on Cd leaching in contaminated soil, outdoor soil column (100 cm) leaching experiments were conducted using two paddy soils irrigated with Pb-Zn mining wastewater. Soil samples which under intercropping systems were collected from Qingyuan City (acid soil with pH 4.63) and Lechang city (neutral soil with pH 6.51), Guangdong Province of China. The mixture of chelators (MC) comprised of citric acid, monosodium glutamate waste liquid, EDTA and KCl with molar ratio of 10 : 1 : 2 : 3 at the concentration of 5 mmol x kg(-1) soil. The intercropping system used in this study was a Zn- and Cd-hyperaccumulator (Sedum alfredii) and a low-accumulating crop (Zea mays). Results showed that at day 2 after the application of MC, the Cd concentrations in leachates from every layer of neutral and acid soils increased significantly in the treatment with intercropping and MC. At day 8 the concentrations of Cd in leachate from layers below 20 cm in the neutral soil and below 60 cm in the acid soil were still significantly higher than those of control. However, the mobility of Cd was decreased greatly compared with that at day 2. At day 2 and day 8 the Cd concentrations in leachates from every layer of neutral and acid soils in the Co-crop + MC treatments exceed the value of the Groundwater Quality Standards (GB/T 14848-93). Cd in all soil columns showed the trend to migrate downwards, especially in the acid soil. The total Cd in the soil layers of 20 cm and 40 cm was decreased by 40% -58% and 39%-49% respectively at the end of the experiments compared to the initial value. After leaching of 100 days,the total Cd in 0-40 cm soil layer of acid soil reached the limit of National Soil Environmental Quality Standards (GB 15618-1995). The results also implied that in Cd-contaminated soil MC addition might enhance the potential risks of Cd contamination in groundwater.

  20. Degradation and metabolism of tetrabromobisphenol A (TBBPA) in submerged soil and soil-plant systems.

    PubMed

    Sun, Feifei; Kolvenbach, Boris Alexander; Nastold, Peter; Jiang, Bingqi; Ji, Rong; Corvini, Philippe Francois-Xavier

    2014-12-16

    Contamination by tetrabromobisphenol A (TBBPA), the most widely used brominated flame retardant, is a matter of environmental concern. Here, we investigated the fate and metabolites of (14)C-TBBPA in a submerged soil with an anoxic-oxic interface and planted or not with rice (Oryza sativa) and reed (Phragmites australis) seedlings. In unplanted soil, TBBPA dissipation (half-life 20.8 days) was accompanied by mineralization (11.5% of initial TBBPA) and the substantial formation (60.8%) of bound residues. Twelve metabolites (10 in unplanted soil and 7 in planted soil) were formed via four interconnected pathways: oxidative skeletal cleavage, O-methylation, type II ipso-substitution, and reductive debromination. The presence of the seedlings strongly reduced (14)C-TBBPA mineralization and bound-residue formation and stimulated debromination and O-methylation. Considerable radioactivity accumulated in rice (21.3%) and reed (33.1%) seedlings, mainly on or in the roots. While TBBPA dissipation was hardly affected by the rice seedlings, it was strongly enhanced by the reed seedlings, greatly reducing the half-life (11.4 days) and increasing monomethyl TBBPA formation (11.3%). The impact of the interconnected aerobic and anaerobic transformation of TBBPA and wetland plants on the profile and dynamics of the metabolites should be considered in phytoremediation strategies and environmental risk assessments of TBBPA in submerged soils. PMID:25402269

  1. Particulate Organic Matter Affects Soil Nitrogen Mineralization under Two Crop Rotation Systems.

    PubMed

    Bu, Rongyan; Lu, Jianwei; Ren, Tao; Liu, Bo; Li, Xiaokun; Cong, Rihuan

    2015-01-01

    Changes in the quantity and/or quality of soil labile organic matter between and after different types of cultivation system could play a dominant role in soil nitrogen (N) mineralization. The quantity and quality of particulate organic matter (POM) and potentially mineralizable-N (PMN) contents were measured in soils from 16 paired rice-rapeseed (RR)/cotton-rapeseed (CR) rotations sites in Hubei province, central China. Then four paired soils encompassing low (10th percentile), intermediate (25th and 75th percentiles), and high (90th percentile) levels of soil PMN were selected to further study the effects of POM on soil N mineralization by quantifying the net N mineralization in original soils and soils from which POM was removed. Both soil POM carbon (POM-C) and N (POM-N) contents were 45.8% and 55.8% higher under the RR rotation compared to the CR rotation, respectively. The PMN contents were highly correlated with the POM contents. The PMN and microbial biomass N (MBN) contents concurrently and significantly decreased when POM was removed. The reduction rate of PMN was positively correlated with changes in MBN after the removal of POM. The reduction rates of PMN and MBN after POM removal are lower under RR rotations (38.0% and 16.3%, respectively) than CR rotations (45.6% and 19.5%, respectively). Furthermore, infrared spectroscopy indicated that compounds with low-bioavailability accumulated (e.g., aromatic recalcitrant materials) in the soil POM fraction under the RR rotation but not under the CR rotation. The results of the present study demonstrated that POM plays a vital role in soil N mineralization under different rotation systems. The discrepancy between POM content and composition resulting from different crop rotation systems caused differences in N mineralization in soils. PMID:26647157

  2. Particulate Organic Matter Affects Soil Nitrogen Mineralization under Two Crop Rotation Systems

    PubMed Central

    Bu, Rongyan; Lu, Jianwei; Ren, Tao; Liu, Bo; Li, Xiaokun; Cong, Rihuan

    2015-01-01

    Changes in the quantity and/or quality of soil labile organic matter between and after different types of cultivation system could play a dominant role in soil nitrogen (N) mineralization. The quantity and quality of particulate organic matter (POM) and potentially mineralizable-N (PMN) contents were measured in soils from 16 paired rice-rapeseed (RR)/cotton-rapeseed (CR) rotations sites in Hubei province, central China. Then four paired soils encompassing low (10th percentile), intermediate (25th and 75th percentiles), and high (90th percentile) levels of soil PMN were selected to further study the effects of POM on soil N mineralization by quantifying the net N mineralization in original soils and soils from which POM was removed. Both soil POM carbon (POM-C) and N (POM-N) contents were 45.8% and 55.8% higher under the RR rotation compared to the CR rotation, respectively. The PMN contents were highly correlated with the POM contents. The PMN and microbial biomass N (MBN) contents concurrently and significantly decreased when POM was removed. The reduction rate of PMN was positively correlated with changes in MBN after the removal of POM. The reduction rates of PMN and MBN after POM removal are lower under RR rotations (38.0% and 16.3%, respectively) than CR rotations (45.6% and 19.5%, respectively). Furthermore, infrared spectroscopy indicated that compounds with low-bioavailability accumulated (e.g., aromatic recalcitrant materials) in the soil POM fraction under the RR rotation but not under the CR rotation. The results of the present study demonstrated that POM plays a vital role in soil N mineralization under different rotation systems. The discrepancy between POM content and composition resulting from different crop rotation systems caused differences in N mineralization in soils. PMID:26647157

  3. Particulate Organic Matter Affects Soil Nitrogen Mineralization under Two Crop Rotation Systems.

    PubMed

    Bu, Rongyan; Lu, Jianwei; Ren, Tao; Liu, Bo; Li, Xiaokun; Cong, Rihuan

    2015-01-01

    Changes in the quantity and/or quality of soil labile organic matter between and after different types of cultivation system could play a dominant role in soil nitrogen (N) mineralization. The quantity and quality of particulate organic matter (POM) and potentially mineralizable-N (PMN) contents were measured in soils from 16 paired rice-rapeseed (RR)/cotton-rapeseed (CR) rotations sites in Hubei province, central China. Then four paired soils encompassing low (10th percentile), intermediate (25th and 75th percentiles), and high (90th percentile) levels of soil PMN were selected to further study the effects of POM on soil N mineralization by quantifying the net N mineralization in original soils and soils from which POM was removed. Both soil POM carbon (POM-C) and N (POM-N) contents were 45.8% and 55.8% higher under the RR rotation compared to the CR rotation, respectively. The PMN contents were highly correlated with the POM contents. The PMN and microbial biomass N (MBN) contents concurrently and significantly decreased when POM was removed. The reduction rate of PMN was positively correlated with changes in MBN after the removal of POM. The reduction rates of PMN and MBN after POM removal are lower under RR rotations (38.0% and 16.3%, respectively) than CR rotations (45.6% and 19.5%, respectively). Furthermore, infrared spectroscopy indicated that compounds with low-bioavailability accumulated (e.g., aromatic recalcitrant materials) in the soil POM fraction under the RR rotation but not under the CR rotation. The results of the present study demonstrated that POM plays a vital role in soil N mineralization under different rotation systems. The discrepancy between POM content and composition resulting from different crop rotation systems caused differences in N mineralization in soils.

  4. Practical improvements in soil redox potential (Eh) measurement for characterisation of soil properties. Application for comparison of conventional and conservation agriculture cropping systems.

    PubMed

    Husson, Olivier; Husson, Benoit; Brunet, Alexandre; Babre, Daniel; Alary, Karine; Sarthou, Jean-Pierre; Charpentier, Hubert; Durand, Michel; Benada, Jaroslav; Henry, Marc

    2016-02-01

    The soil redox potential (Eh) can provide essential information to characterise soil conditions. In practice, however, numerous problems may arise regarding: (i) Eh determination in soils, especially aerobic soils, e.g. variations in the instrumentation and methodology for Eh measurement, high spatial and temporal Eh variability in soils, irreversibility of the redox reaction at the surface electrode, chemical disequilibrium; and (ii) measurement interpretation. This study aimed at developing a standardised method for redox potential measurement in soils, in order to use Eh as a soil quality indicator. This paper presents practical improvements in soil Eh measurement, especially regarding the control of electromagnetic perturbations, electrode choice and preparation, soil sample preparation (drying procedure) and soil:water extraction rate. The repeatability and reproducibility of the measurement method developed are highlighted. The use of Eh corrected at pH7, pe+pH or rH2, which are equivalent notions, is proposed to facilitate interpretation of the results. The application of this Eh measurement method allows characterisation of soil conditions with sufficient repeatability, reproducibility and accuracy to demonstrate that conservation agriculture systems positively alter the protonic and electronic balance of soil as compared to conventional systems.

  5. Practical improvements in soil redox potential (Eh) measurement for characterisation of soil properties. Application for comparison of conventional and conservation agriculture cropping systems.

    PubMed

    Husson, Olivier; Husson, Benoit; Brunet, Alexandre; Babre, Daniel; Alary, Karine; Sarthou, Jean-Pierre; Charpentier, Hubert; Durand, Michel; Benada, Jaroslav; Henry, Marc

    2016-02-01

    The soil redox potential (Eh) can provide essential information to characterise soil conditions. In practice, however, numerous problems may arise regarding: (i) Eh determination in soils, especially aerobic soils, e.g. variations in the instrumentation and methodology for Eh measurement, high spatial and temporal Eh variability in soils, irreversibility of the redox reaction at the surface electrode, chemical disequilibrium; and (ii) measurement interpretation. This study aimed at developing a standardised method for redox potential measurement in soils, in order to use Eh as a soil quality indicator. This paper presents practical improvements in soil Eh measurement, especially regarding the control of electromagnetic perturbations, electrode choice and preparation, soil sample preparation (drying procedure) and soil:water extraction rate. The repeatability and reproducibility of the measurement method developed are highlighted. The use of Eh corrected at pH7, pe+pH or rH2, which are equivalent notions, is proposed to facilitate interpretation of the results. The application of this Eh measurement method allows characterisation of soil conditions with sufficient repeatability, reproducibility and accuracy to demonstrate that conservation agriculture systems positively alter the protonic and electronic balance of soil as compared to conventional systems. PMID:26772129

  6. Elaboration of the Soil Monitoring Module of the Hungarian Agro-Environmental Program and preparation of the National Soil Degradation Monitoring System

    NASA Astrophysics Data System (ADS)

    Szabó, J.; Pásztor, L.; Dombos, M.; Pirkó, B.; Bakacsi, Zs; Laborczi, A.

    2009-04-01

    The National Agri-Environmental Program (NAEP) started in 2000 in Hungary. The Monitoring System of NAEP aims at the demonstration of improving influences of the various agri-environmental target projects on the state of the environment. The expected positive regional effects can be proven by appropriate spatio-temporal analysis of permanently expanding and suitably linked thematic databases. The two main environmental targets of the programs are biodiversity and soil. As a consequence there are strong expectations on adequate and continuous soil state evaluation, which can support the verification of the realized objectives. The Soil Monitoring System of NAEP represents the framework of the related activities. In our paper we present the pursuits carried out for the elaboration of the system, which involved the followings: - Definition of soil state features, soil functions, soil processes, soil threats and degradation processes which can be related to the presumable improving effects of the various agri-environmental target projects in order to be monitored. - Working out of a complex, hierarchic sampling strategy (definition and designation of sampling units representing multipurpose spatial representativity; determination of their number and spatial distribution). - Selection of appropriate soil indicators. - Elaboration of protocols for the measurement parameters of the selected indicators. - Spatio-temporal redistribution of measurements along the predefined sampling units and over time. - Estimation of financial aspects of the actuation of the system. The elaboration of the Soil Monitoring Module of NAEP also initiated a program for the establishment of a national soil monitoring system for the follow up of the (harmful) changes in soil conditions. The planned National Soil Degradation Monitoring System should support the inauguration of the European Soil Framework Directive. A successful proposal opened the feasibility of such a system; its scheme and

  7. The Frequency and Damping of Soil-Structure Systems with Embedded Foundation

    SciTech Connect

    Ghannad, M. Ali; Rahmani, Mohammad T.; Jahankhah, Hossein

    2008-07-08

    The effect of foundation embedment on fundamental period and damping of buildings has been the title of several researches in three past decades. A review of the literature reveals some discrepancies between proposed formulations for dynamic characteristics of soil-embedded foundation-structure systems that raise the necessity of more investigation on this issue. Here, first a set of approximate polynomial equations for soil impedances, based on numerical data calculated from well known cone models, are presented. Then a simplified approach is suggested to calculate period and damping of the whole system considering soil medium as a viscoelastic half space. The procedure includes both material and radiation damping while frequency dependency of soil impedance functions is not ignored. Results show that soil-structure interaction can highly affect dynamic properties of system. Finally the results are compared with one of the commonly referred researches.

  8. Impact of Organic and Conventional Systems of Coffee Farming on Soil Properties and Culturable Microbial Diversity.

    PubMed

    Velmourougane, Kulandaivelu

    2016-01-01

    A study was undertaken with an objective of evaluating the long-term impacts of organic (ORG) and conventional (CON) methods of coffee farming on soil physical, chemical, biological, and microbial diversity. Electrical conductivity and bulk density were found to increase by 34% and 21%, respectively, in CON compared to ORG system, while water holding capacity was found decreased in both the systems. Significant increase in organic carbon was observed in ORG system. Major nutrients, nitrogen and potassium, levels showed inclination in both ORG and CON system, but the trend was much more pronounced in CON system. Phosphorus was found to increase in both ORG and CON system, but its availability was found to be more with CON system. In biological attributes, higher soil respiration and fluorescein diacetate activity were recorded in ORG system compared to CON system. Higher soil urease activity was observed in CON system, while dehydrogenase activity does not show significant differences between ORG and CON systems. ORG system was found to have higher macrofauna (31.4%), microbial population (34%), and microbial diversity indices compared to CON system. From the present study, it is accomplished that coffee soil under long-term ORG system has better soil properties compared to CON system.

  9. Impact of Organic and Conventional Systems of Coffee Farming on Soil Properties and Culturable Microbial Diversity

    PubMed Central

    2016-01-01

    A study was undertaken with an objective of evaluating the long-term impacts of organic (ORG) and conventional (CON) methods of coffee farming on soil physical, chemical, biological, and microbial diversity. Electrical conductivity and bulk density were found to increase by 34% and 21%, respectively, in CON compared to ORG system, while water holding capacity was found decreased in both the systems. Significant increase in organic carbon was observed in ORG system. Major nutrients, nitrogen and potassium, levels showed inclination in both ORG and CON system, but the trend was much more pronounced in CON system. Phosphorus was found to increase in both ORG and CON system, but its availability was found to be more with CON system. In biological attributes, higher soil respiration and fluorescein diacetate activity were recorded in ORG system compared to CON system. Higher soil urease activity was observed in CON system, while dehydrogenase activity does not show significant differences between ORG and CON systems. ORG system was found to have higher macrofauna (31.4%), microbial population (34%), and microbial diversity indices compared to CON system. From the present study, it is accomplished that coffee soil under long-term ORG system has better soil properties compared to CON system. PMID:27042378

  10. RADON REDUCTION TECHNIQUES FOR EXISTING DETACHED HOUSES - TECHNICAL GUIDANCE (THIRD EDITION) FOR ACTIVE SOIL DEPRESSURIZATION SYSTEMS

    EPA Science Inventory

    This technical guidance document is designed to aid in the selection, design, installation and operation of indoor radon reduction techniques using soil depressurization in existing houses. Its emphasis is on active soil depressurization; i.e., on systems that use a fan to depre...

  11. Impacts of organic conservation tillage systems on crops, weeds, and soil quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic farming has been identified as promoting soil quality even though tillage is used for weed suppression. Adopting conservation tillage practices can enhance soil quality in cropping systems where synthetic agrichemicals are used for crop nutrition and weed control. Attempts have been made t...

  12. BESCORP SOIL WASHING SYSTEM FOR LEAD BATTERY SITE TREATMENT - APPLICATIONS ANALYSIS REPORT

    EPA Science Inventory

    This report evaluates the Brice Environmental Services Corporation (BESCORP) Soil Washing System (BSWS) and Its applicability in remediating lead-contaminated soil at lead battery sites. It presents performance and economic data, developed from the U.S. Environmental Protection A...

  13. Remediation of Stratified Soil Acidity Through Surface Application of Lime in No-Till Cropping Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Yield reduction and reduced crop vigor, resulting from soil acidification, are of increasing concern in eastern Washington and northern Idaho. In this region, soil pH has been decreasing at an accelerated rate, primarily due to the long-term use of ammonium based fertilizers. In no-till systems, the...

  14. Soil water infiltration affected by biofuel and grain crop production systems in claypan landscape

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of soil management systems on water infiltration is very crucial within claypan landscapes to maximize production as well as minimize environmental risks. The objective of this study was to assess the effect of topsoil thickness on water infiltration in claypan soils for grain and biofuel...

  15. Distribution of oxidizable organic c fractions in soils under cacao agroforestry systems in Southern Bahia, Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agroforestry systems can play a major role in the sequestration of carbon (C) because of their higher input of organic materials to the soil. The importance of organic carbon to the physical, chemical, and biological aspects of soil quality is well recognized. However, total organic carbon measureme...

  16. Distribution of organic C oxidizable fractions in soils under cacao agroforestry systems in southern Bahia, Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agroforestry systems can play a major role in the sequestration of carbon (C) because of their higher input of organic material to the soil. The importance of organic carbon to the physical, chemical, and biological aspects of soil quality is well recognized. However, total organic carbon measuremen...

  17. Sheep grazing effect on dryland soil carbon and nitrogen in the wheat-fallow system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control by sheep grazing during fallow periods in the dryland wheat-fallow system may influence soil C and N levels. The effects of fallow management for weed control and soil water conservation [sheep grazing (grazing), herbicide application (chemical), and tillage (mechanical)] and cropping s...

  18. Effects of cropping and tillage systems on soil erosion under climate change in Oklahoma

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil erosion under future climate change is very likely to increase due to projected increases in frequency and magnitude of heavy storms. The objective of this study is to quantify the effects of common cropping and tillage systems on soil erosion and surface runoff during 2010-2039 in central Okl...

  19. Cropping and tillage systems effects on soil erosion under climate change in Oklahoma

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil erosion under future climate change is very likely to increase due to projected increases in frequency and magnitude of heavy storms. The objective of this study is to quantify the effects of common cropping and tillage systems on soil erosion and surface runoff during 2010-2039 in central Okl...

  20. Impacts of an integrated crop-livestock system on soil properties to enhance precipitation capture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cropping/Livestock systems alter soil properties that are important in enhancing capture of precipitation by developing and maintaining water infiltration and storage. In this paper we will relate soil hydraulic conductivity and other physical properties on managed Old World Bluestem grassland, whea...

  1. Ecologically-based management improves soil health in an organic orchard production system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prairie Birthday Farm (PBF), a diversified, organic enterprise on the loess hill landscape in northwestern Missouri, was previously managed as a conventional corn-soybean production system. The soil (Sharpsburg silt loam; fine, montmorillonitic, mesic Typic Argiudolls) is mapped as an ‘eroded soil p...

  2. Carbon Storage in Soil Size Fractions Under Two Cacao Agroforestry Systems in Bahia, Brazil

    NASA Astrophysics Data System (ADS)

    Gama-Rodrigues, Emanuela F.; Ramachandran Nair, P. K.; Nair, Vimala D.; Gama-Rodrigues, Antonio C.; Baligar, Virupax C.; Machado, Regina C. R.

    2010-02-01

    Shaded perennial agroforestry systems contain relatively high quantities of soil carbon (C) resulting from continuous deposition of plant residues; however, the extent to which the C is sequestered in soil will depend on the extent of physical protection of soil organic C (SOC). The main objective of this study was to characterize SOC storage in relation to soil fraction-size classes in cacao ( Theobroma cacao L.) agroforestry systems (AFSs). Two shaded cacao systems and an adjacent natural forest in reddish-yellow Oxisols in Bahia, Brazil were selected. Soil samples were collected from four depth classes to 1 m depth and separated by wet-sieving into three fraction-size classes (>250 μm, 250-53 μm, and <53 μm)—corresponding to macroaggregate, microaggregate, and silt-and-clay size fractions—and analyzed for C content. The total SOC stock did not vary among systems (mean: 302 Mg/ha). On average, 72% of SOC was in macroaggregate-size, 20% in microaggregate-size, and 8% in silt-and-clay size fractions in soil. Sonication of aggregates showed that occlusion of C in soil aggregates could be a major mechanism of C protection in these soils. Considering the low level of soil disturbances in cacao AFSs, the C contained in the macroaggregate fraction might become stabilized in the soil. The study shows the role of cacao AFSs in mitigating greenhouse gas (GHG) emission through accumulation and retention of high amounts of organic C in the soils and suggests the potential benefit of this environmental service to the nearly 6 million cacao farmers worldwide.

  3. Carbon storage in soil size fractions under two cacao agroforestry systems in Bahia, Brazil.

    PubMed

    Gama-Rodrigues, Emanuela F; Ramachandran Nair, P K; Nair, Vimala D; Gama-Rodrigues, Antonio C; Baligar, Virupax C; Machado, Regina C R

    2010-02-01

    Shaded perennial agroforestry systems contain relatively high quantities of soil carbon (C) resulting from continuous deposition of plant residues; however, the extent to which the C is sequestered in soil will depend on the extent of physical protection of soil organic C (SOC). The main objective of this study was to characterize SOC storage in relation to soil fraction-size classes in cacao (Theobroma cacao L.) agroforestry systems (AFSs). Two shaded cacao systems and an adjacent natural forest in reddish-yellow Oxisols in Bahia, Brazil were selected. Soil samples were collected from four depth classes to 1 m depth and separated by wet-sieving into three fraction-size classes (>250 microm, 250-53 microm, and <53 microm)-corresponding to macroaggregate, microaggregate, and silt-and-clay size fractions-and analyzed for C content. The total SOC stock did not vary among systems (mean: 302 Mg/ha). On average, 72% of SOC was in macroaggregate-size, 20% in microaggregate-size, and 8% in silt-and-clay size fractions in soil. Sonication of aggregates showed that occlusion of C in soil aggregates could be a major mechanism of C protection in these soils. Considering the low level of soil disturbances in cacao AFSs, the C contained in the macroaggregate fraction might become stabilized in the soil. The study shows the role of cacao AFSs in mitigating greenhouse gas (GHG) emission through accumulation and retention of high amounts of organic C in the soils and suggests the potential benefit of this environmental service to the nearly 6 million cacao farmers worldwide.

  4. 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.

  5. Soil sampling sensor system on a mobile robot

    NASA Astrophysics Data System (ADS)

    Cao, Peter M.; Hall, Ernest L.; Zhang, Evan

    2003-10-01

    Determining if a segment of property is suitable for use as an aircraft is a vitally important task that is currently performed by humans. However, this task can also put our people in harms way from land mines, sniper and artillery attacks. The objective of this research is to build a soil survey manipulator that can be carried by a lightweight, portable, autonomous vehicle, sensors and controls to navigate in assault zone. The manipulators permit both surface and sub surface measurements. An original soil sampling tube was constructed with linear actuator as manipulator and standard penetrometer as sampling sensor. The controls provide local control of the robot as well as the soil sampling mechanism. GPS has been selected to perform robot global navigation. The robot was constructed and tested on the test field. The results verified the concepts of using soil sampling robot to survey runway is feasible.

  6. Towards a paradigm shift in the modeling of soil organic carbon decomposition for earth system models

    NASA Astrophysics Data System (ADS)

    He, Yujie

    Soils are the largest terrestrial carbon pools and contain approximately 2200 Pg of carbon. Thus, the dynamics of soil carbon plays an important role in the global carbon cycle and climate system. Earth System Models are used to project future interactions between terrestrial ecosystem carbon dynamics and climate. However, these models often predict a wide range of soil carbon responses and their formulations have lagged behind recent soil science advances, omitting key biogeochemical mechanisms. In contrast, recent mechanistically-based biogeochemical models that explicitly account for microbial biomass pools and enzyme kinetics that catalyze soil carbon decomposition produce notably different results and provide a closer match to recent observations. However, a systematic evaluation of the advantages and disadvantages of the microbial models and how they differ from empirical, first-order formulations in soil decomposition models for soil organic carbon is still needed. This dissertation consists of a series of model sensitivity and uncertainty analyses and identifies dominant decomposition processes in determining soil organic carbon dynamics. Poorly constrained processes or parameters that require more experimental data integration are also identified. This dissertation also demonstrates the critical role of microbial life-history traits (e.g. microbial dormancy) in the modeling of microbial activity in soil organic matter decomposition models. Finally, this study surveys and synthesizes a number of recently published microbial models and provides suggestions for future microbial model developments.

  7. On site experiments of the slanted soil treatment systems for domestic gray water.

    PubMed

    Itayama, Tomoaki; Kiji, Masato; Suetsugu, Aya; Tanaka, Nobuyuki; Saito, Takeshi; Iwami, Norio; Mizuochi, Motoyuki; Inamori, Yuhei

    2006-01-01

    In order to make a breakthrough for the acute problem of water shortage in the world, the key words "decentralization and re-use" are very important for new sustainable sanitation systems that will be developed. Therefore, we focused on a new treatments system called "a slanted soil treatment system" which combines a biotoilet system with a domestic grey water treatment system. Because this system is a low cost and compact system, the system can be easily introduced to homes in urban areas or in the suburbs of cities in many developing countries. In this study, we performed on site experiments carried out on Shikoku Island, Japan, for several years. We obtained the following results. The slanted soil treatment system could remove organic pollutants and total nitrogen and total phosphorus in grey water effectively. Furthermore, the system performance became high in the case of the high concentration of the influent water. The nitrification reaction and denitrification reaction were speculated to exist due to aerobic zones and anaerobic zones present in the slanted soil treatment system. The slanted soil treatment system could perform for approximately 3 years with zero maintenance. The plug flow model of 1st order reaction kinetics could describe the reaction in the slanted soil treatment system. However, it is necessary to improve the system to maintain the performance in all seasons.

  8. The DIGISOIL multi-sensor system: from geophysical measurements to soil properties.

    NASA Astrophysics Data System (ADS)

    Grandjean, Gilles

    2010-05-01

    The purposes of the multidisciplinary DIGISOIL project are the integration and improvement of in situ and proximal measurement technologies for the assessment of soil properties and soil degradation indicators, going from the sensing technologies to their integration and their application in (digital) soil mapping (DSM). In order to assess and prevent soil degradation and to benefit from the different ecological, economical and historical functions of the soil in a sustainable way, high resolution and quantitative maps of soil properties are needed. The core objective of the project is to explore and exploit new capabilities of advanced geophysical technologies for answering this societal demand. To this aim, DIGISOIL addresses four issues covering technological, soil science and economic aspects: (i) the validation of geophysical (in situ, proximal and airborne) technologies and integrated pedo-geophysical inversion techniques (mechanistic data fusion) (ii) the relation between the geophysical parameters and the soil properties, (iii) the integration of the derived soil properties for mapping soil functions and soil threats, (iv) the pre-evaluation, standardisation and sub-industrialization of the proposed methodologies, including technical and economical studies related to the societal demand. With respect to these issues, the preliminary tasks of the DIGISOIL project were to develop, test and validate the most relevant geophysical technologies for mapping soil properties. The different field tests, realized at this time, allow focusing on technological suitable solutions for each of the identified methods: geoelectric, GPR, EMI, seismics, magnetic and hyperspectral. After data acquisition systems, sensor geometry, and advanced data processing techniques have been developed and validated, we present now the solutions for going from such data to soil properties maps.

  9. Role of native and exotic woody vegetation in soil restoration in active gully systems (southern Ecuador)

    NASA Astrophysics Data System (ADS)

    Borja Ramon, Pablo; Alvarado Moncayo, Dario; Vanacker, Veerle; Cisneros, Pedro; Molina, Armando; Govers, Gerard

    2015-04-01

    Revegetation projects in degraded lands have the potential to recover essential soil functions. If vegetation restoration is combined with bioengineering techniques, such as the construction of retention dams in active gully systems, soil restoration could be enhanced. One important aspect of this process is the role of vegetation on restoration of soil chemical and physical properties. There is currently a lack of knowledge on the potential of soil restoration in active badland systems, as most studies have concentrated on the direct and visible effect of revegetation on erosion control. The aim of this study is to evaluate the role of revegetation and bioengineering works on the restoration of soil physical and chemical properties. The analyses are realized in a highly degraded area of 3 km2, located in the lower part of the Loreto catchment (Southern Ecuadorian Andes). First, the soil physical and/or chemical parameters that are most sensitive to track environmental change were evaluated. Second, the role of vegetation on soil restoration was quantified. . Soil samples were taken in sites with different vegetation cover, land use and physiographic position. The following physical and chemical parameters were measured: volumetric water content (θsat, θact), bulk density, pH, texture, organic matter, C and N content. Our first results do not show a clear relationship between volumetric water content at saturation (θsat), bulk density, or C content. The saturation water content does not vary significantly between different sites, or land use types. However, significant differences are found between sites at different stages of restoration; and this for most chemical and physical soil properties. Vegetation cover (%) appears to exert a strong control on the C content in the mineral soils. The highest C values are found in soils of forest plantations with Eucalyptus and Pinus species. These plantations are located in areas that were previously affected by active

  10. Biogeochemical transfer and dynamics of iodine in a soil-plant system.

    PubMed

    Weng, Huan-Xin; Yan, Ai-Lan; Hong, Chun-Lai; Qin, Ya-Chao; Pan, Lehua; Xie, Ling-Li

    2009-06-01

    Radioactive iodide (125I) is used as a tracer to investigate the fate and transport of iodine in soil under various leaching conditions as well as the dynamic transfer in a soil-plant (Chinese cabbage) system. Results show that both soils (the paddy soil and the sandy soil) exhibit strong retention capability, with the paddy soil being slightly stronger. Most iodine is retained by soils, especially in the top 10 cm, and the highest concentration occurs at the top most section of the soil columns. Leaching with 1-2 pore volume water does not change this pattern of vertical distributions. Early breakthrough and long tailing are two features observed in the leaching experiments. Because of the relatively low peak concentration, the early breakthrough is really not an environmental concern of contamination to groundwater. The long tailing implies that the retained iodine is undergoing slow but steady release and the soils can provide a low but stable level of mobile iodine after a short period. The enrichment factors of 125I in different plant tissues are ranked as: root > stem > petiole > leaf, and the 125I distribution in the young leaves is obviously higher than that in the old ones. The concentrations of 125I in soil and Chinese cabbage can be simulated with a dual-chamber model very well. The biogeochemical behaviors of iodine in the soil-cabbage system show that cultivating iodized cabbage is an environmentally friendly and effective technique to eliminate iodine deficiency disorders (IDD). Planting vegetables such as cabbage on the 129I-contaminated soil could be a good remediation technique worthy of consideration.

  11. Experimental analysis of CO₂ emissions from agricultural soils subjected to five different tillage systems in Lithuania.

    PubMed

    Buragienė, Sidona; Šarauskis, Egidijus; Romaneckas, Kęstutis; Sasnauskienė, Jurgita; Masilionytė, Laura; Kriaučiūnienė, Zita

    2015-05-01

    Intensive agricultural production strongly influences the global processes that determine climate change. Thus, tillage can play a very important role in climate change. The intensity of soil carbon dioxide (CO₂) emissions, which contribute to the greenhouse effect, can vary depending on the following factors: the tillage system used, meteorological conditions (which vary in different regions of the world), soil properties, plant residue characteristics and other factors. The main purpose of this research was to analyse and assess the effects of autumn tillage systems with different intensities on CO₂ emissions from soils during different seasons and under the climatic conditions of Central Lithuania. The research was conducted at the Experimental Station of Aleksandras Stulginskis University from 2009 to 2012; and in 2014. The soils at the experimental site were classified as Eutric Endogleyic Planosol (Drainic). The investigations were conducted using five tillage systems with different intensities, typical of the Baltic Region. Deep conventional ploughing was performed at a depth of 230-250 mm, shallow ploughing was conducted at a depth of 120-150 mm, deep loosening was conducted at depths of 250-270 mm, and shallow loosening was conducted at depths of 120-150 mm. The fifth system was a no-tillage system. Overall, autumn tillage resulted in greater CO₂ emissions from the soil over both short- and long-term periods under the climatic conditions of Central Lithuania, regardless of the tillage system applied. The highest soil CO₂ emissions were observed for the conventional deep ploughing tillage system, and the lowest emissions were observed for the no-tillage system. The meteorological conditions greatly influenced the CO₂ emissions from the soil during the spring. Soil CO₂ emissions were enhanced as precipitation and the air and soil temperatures increased. Long-term investigations regarding the dynamics of CO₂ emissions from soils during the maize

  12. Experimental analysis of CO₂ emissions from agricultural soils subjected to five different tillage systems in Lithuania.

    PubMed

    Buragienė, Sidona; Šarauskis, Egidijus; Romaneckas, Kęstutis; Sasnauskienė, Jurgita; Masilionytė, Laura; Kriaučiūnienė, Zita

    2015-05-01

    Intensive agricultural production strongly influences the global processes that determine climate change. Thus, tillage can play a very important role in climate change. The intensity of soil carbon dioxide (CO₂) emissions, which contribute to the greenhouse effect, can vary depending on the following factors: the tillage system used, meteorological conditions (which vary in different regions of the world), soil properties, plant residue characteristics and other factors. The main purpose of this research was to analyse and assess the effects of autumn tillage systems with different intensities on CO₂ emissions from soils during different seasons and under the climatic conditions of Central Lithuania. The research was conducted at the Experimental Station of Aleksandras Stulginskis University from 2009 to 2012; and in 2014. The soils at the experimental site were classified as Eutric Endogleyic Planosol (Drainic). The investigations were conducted using five tillage systems with different intensities, typical of the Baltic Region. Deep conventional ploughing was performed at a depth of 230-250 mm, shallow ploughing was conducted at a depth of 120-150 mm, deep loosening was conducted at depths of 250-270 mm, and shallow loosening was conducted at depths of 120-150 mm. The fifth system was a no-tillage system. Overall, autumn tillage resulted in greater CO₂ emissions from the soil over both short- and long-term periods under the climatic conditions of Central Lithuania, regardless of the tillage system applied. The highest soil CO₂ emissions were observed for the conventional deep ploughing tillage system, and the lowest emissions were observed for the no-tillage system. The meteorological conditions greatly influenced the CO₂ emissions from the soil during the spring. Soil CO₂ emissions were enhanced as precipitation and the air and soil temperatures increased. Long-term investigations regarding the dynamics of CO₂ emissions from soils during the maize

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  14. Soil chemical sensor and precision agricultural chemical delivery system and method

    DOEpatents

    Colburn, J.W. Jr.

    1991-07-23

    A real time soil chemical sensor and precision agricultural chemical delivery system includes a plurality of ground-engaging tools in association with individual soil sensors which measure soil chemical levels. The system includes the addition of a solvent which rapidly saturates the soil/tool interface to form a conductive solution of chemicals leached from the soil. A multivalent electrode, positioned within a multivalent frame of the ground-engaging tool, applies a voltage or impresses a current between the electrode and the tool frame. A real-time soil chemical sensor and controller senses the electrochemical reaction resulting from the application of the voltage or current to the leachate, measures it by resistivity methods, and compares it against pre-set resistivity levels for substances leached by the solvent. Still greater precision is obtained by calibrating for the secondary current impressed through solvent-less soil. The appropriate concentration is then found and the servo-controlled delivery system applies the appropriate amount of fertilizer or agricultural chemicals substantially in the location from which the soil measurement was taken. 5 figures.

  15. Soil chemical sensor and precision agricultural chemical delivery system and method

    DOEpatents

    Colburn, Jr., John W.

    1991-01-01

    A real time soil chemical sensor and precision agricultural chemical delivery system includes a plurality of ground-engaging tools in association with individual soil sensors which measure soil chemical levels. The system includes the addition of a solvent which rapidly saturates the soil/tool interface to form a conductive solution of chemicals leached from the soil. A multivalent electrode, positioned within a multivalent frame of the ground-engaging tool, applies a voltage or impresses a current between the electrode and the tool frame. A real-time soil chemical sensor and controller senses the electrochemical reaction resulting from the application of the voltage or current to the leachate, measures it by resistivity methods, and compares it against pre-set resistivity levels for substances leached by the solvent. Still greater precision is obtained by calibrating for the secondary current impressed through solvent-less soil. The appropriate concentration is then found and the servo-controlled delivery system applies the appropriate amount of fertilizer or agricultural chemicals substantially in the location from which the soil measurement was taken.

  16. Effect of tillage system on soil temperature in a rainfed Mediterranean Vertisol

    NASA Astrophysics Data System (ADS)

    Muñoz-Romero, Veronica; Lopez-Bellido, Luis; Lopez-Bellido, Rafael J.

    2015-10-01

    Soil temperature is a factor that influences the rates of physical, chemical, and biological reactions in soils and has a strong influence on plant growth. A field study was conducted during 2006-2007 and 2009-2010 on a typical rainfed Mediterranean Vertisol to determine the effects of the tillage system and the crop on soil temperature. The experimental treatments were the tillage system (no-tillage and conventional tillage) and the crop (wheat and faba bean). Soil temperature was measured at a 20 cm depth at 1 h intervals from December 1st to November 30th of 2006-2007 and 2009-2010. There was a highly significant relationship between air temperature (both maximum and minimum) and soil temperature for the two tillage systems. Soil temperature was similar in the growing season for both crops but was higher in the conventional tillage than in the no-tillage system, with differences between 0.7 and 2.6°C depending on the month of the year. A higher soil temperature with conventional tillage can be beneficial in the cold sowing period (November-December), improving crop establishment. In contrast, in critical periods with water deficits (spring) during which grain formation occurs, the lower temperature corresponding to the no-tillage system would be more favourable.

  17. Developing an Operational System for Daily 800-m Resolution Soil Moisture Estimates across Oklahoma

    NASA Astrophysics Data System (ADS)

    Ochsner, T. E.; Patton, J. C.; Dong, J.; Patrignani, A.; Haffner, M.

    2015-12-01

    Researchers often need meso-scale, high resolution soil moisture estimates for research and decision support in the areas of hydrology, agriculture, and ecology. However, current soil moisture measurement techniques are commonly inadequate in terms of spatial resolution (satellites), spatial support or density (in situ networks), or temporal resolution (rovers). The development of operational systems for high resolution soil moisture estimation will create opportunities for improved drought monitoring, flood forecasting, agricultural management, and wildfire preparedness, as well as for calibration and validation of soil moisture satellites. We are working to develop such an estimation system by merging multiple information sources including: a statewide, mesoscale network (the Oklahoma Mesonet), a cosmic-ray neutron rover, high resolution land cover data, and a proven soil water balance model. This presentation will describe our vision and motivations, our methods, and our progress to date.

  18. Benchmarking a Soil Moisture Data Assimilation System for Agricultural Drought Monitoring

    NASA Technical Reports Server (NTRS)

    Hun, Eunjin; Crow, Wade T.; Holmes, Thomas; Bolten, John

    2014-01-01

    Despite considerable interest in the application of land surface data assimilation systems (LDAS) for agricultural drought applications, relatively little is known about the large-scale performance of such systems and, thus, the optimal methodological approach for implementing them. To address this need, this paper evaluates an LDAS for agricultural drought monitoring by benchmarking individual components of the system (i.e., a satellite soil moisture retrieval algorithm, a soil water balance model and a sequential data assimilation filter) against a series of linear models which perform the same function (i.e., have the same basic inputoutput structure) as the full system component. Benchmarking is based on the calculation of the lagged rank cross-correlation between the normalized difference vegetation index (NDVI) and soil moisture estimates acquired for various components of the system. Lagged soil moistureNDVI correlations obtained using individual LDAS components versus their linear analogs reveal the degree to which non-linearities andor complexities contained within each component actually contribute to the performance of the LDAS system as a whole. Here, a particular system based on surface soil moisture retrievals from the Land Parameter Retrieval Model (LPRM), a two-layer Palmer soil water balance model and an Ensemble Kalman filter (EnKF) is benchmarked. Results suggest significant room for improvement in each component of the system.

  19. Disentangling the drivers of soil organic matter decay as temperature changes by integrating reductionist systems with soil data

    NASA Astrophysics Data System (ADS)

    Billings, Sharon; Ballantyne, Ford, IV; Min, Kyungjin; Lehmeier, Christoph; Ziegler, Susan

    2014-05-01

    Accurately predicting decomposition rates of soil organic matter (SOM) as temperature increases is critical for projecting future atmospheric [CO2]. SOM decay is catalyzed by exo-enzymes (EEs) produced by microorganisms and secreted into the soil. Microbes take up liberated resources for metabolic processes and release diverse compounds, including CO2. Historically, investigations of the influence of temperature on heterotrophic CO2 release have focused on CO2 response, including its isotopic composition; recent studies also assess EE activity and microbial community composition. However, it is difficult to generalize from such studies how temperature will influence SOM decay and CO2 release because the responses of EEs, microbial resource demand, biomass production rates, and respiration rates are not parsed. Quantifying the individual temperature responses of all of these processes in unaltered soil is not tractable. However, we can use experimentally simplified systems to quantify fundamental biochemical and physiological responses to temperature and compare these results to those from environmental samples. For example, we can quantify the degree to which EE kinetics in isolation induce changes in availability of microbially assimilable resources as temperature changes and calculate associated changes in relative availability of assimilable carbon and nitrogen (C:N flow ratio), in isolation from altered microbial resource demand or uptake. We also can assess EE activity and CO2 release at different temperatures in diverse soils, integrating temperature responses of EE kinetics and microbial communities. Discrepancies in the temperature responses between real soils and isolated enzyme-substrate reactions can reveal how adaptive responses of microbial communities influence the temperature responses of soil heterotrophic CO2 release. We have shown in purified reactions that C:N flow ratios increase with temperature at pH 4.5, but decline between pH 6.5 and 8.5. If

  20. First results of the DIGISOIL multi-sensor system for mapping soil properties

    NASA Astrophysics Data System (ADS)

    Grandjean, G.

    2009-04-01

    The purposes of the multidisciplinary DIGISOIL project are the integration and improvement of in situ and proximal measurement technologies for the assessment of soil properties and soil degradation indicators, going from the sensing technologies to their integration and their application in (digital) soil mapping (DSM). In order to assess and prevent soil degradation and to benefit from the different ecological, economical and historical functions of the soil in a sustainable way, high resolution and accurate maps of soil properties are needed. The core objective of the project is to explore and exploit new capabilities of advanced geophysical technologies for answering this societal demand. To this aim, DIGISOIL addresses four issues covering technological, soil science and economic aspects (Figure 1): (i) the validation of geophysical (in situ, proximal and airborne) technologies and integrated pedo-geophysical inversion techniques (mechanistic data fusion) (ii) the relation between the geophysical parameters and the soil properties, (iii) the integration of the derived soil properties for mapping soil functions and soil threats, (iv) the evaluation, standardisation and sub-industrialization of the proposed methodologies, including technical and economical studies. With respect to these issues, the preliminary tasks of the DIGISOIL project were to develop, test and validate the most relevant geophysical technologies for mapping soil properties. The different field tests, realized at this time, allow focusing on technological suitable solutions for each of identified methods: geoelectric, GPR, seismics, magnetic and hyperspectral. Data acquisition systems, sensor geometry, data processing are thus presented and discussed in the perspectives of producing information layers for Digital Soil Mapping. Next tasks will be dedicated to (i) establish correlations between the measured geophysical measurements and the soil properties involved in soil functions / threats

  1. Heavy metal contents, distribution, and prediction in a regional soil-wheat system.

    PubMed

    Ran, Jing; Wang, Dejian; Wang, Can; Zhang, Gang; Zhang, Hailin

    2016-02-15

    The entry of heavy metals into the food chain is of concern for potential health risks. To investigate the spatial relationships of heavy metals in a regional soil-wheat system, 99 pairs of surface soil (0-15 cm) and wheat grain samples were collected from Changshu, China, a typical county in the Yangtze Delta region. Both soil and wheat grain samples were analyzed for total Cd, Cu, Ni, Pb, and Zn. DTPA-extractable metals and major physico-chemical properties were also determined for soil samples. Moderate accumulation of heavy metals was found in soils and wheat grains, especially Cd. However, the levels were within the target hazard quotients (THQ) safe values with respect to non-carcinogenic risks, but more attention should be paid to Cd. Spatially, Cd, Cu, Ni, and Zn in wheat grains and soils had similar geographical patterns, whereas Pb showed opposite trends. Cross-correlograms further quantitatively confirmed the spatial relationships of heavy metals in wheat grains and soils. In addition, heavy metals in wheat grains were significantly spatially correlated with most soil physio-chemical properties. Particularly, a set of regression models for Cd in wheat grains were established with a maximum predictive success of 65%. These models can be used to predict Cd in wheat grains, and thus allows farmers to decrease the threat by certain framing practices such as ameliorating soil pH or growing a less metal-accumulating cultivar. PMID:26657387

  2. Toxicity of the antimicrobial oxytetracycline to soil organisms in a multi-species-soil system (MS.3) and influence of manure co-addition.

    PubMed

    Boleas, Sara; Alonso, Carmen; Pro, Javier; Fernández, Carlos; Carbonell, Gregoria; Tarazona, Jose V

    2005-07-15

    The effects of oxytetracycline (OTC) on soil organisms have been studied using a multi-species-soil system (MS.3). Oxytetracycline concentrations of 0.01 mg/kg, 1 mg/kg and 100 mg/kg soil were added to the 20 cm top arable soil layer, with and without horse/cow manure (0.15 g organic N/kg soil) co-addition. No mortality was observed for Eisenia foetida S. but significant effects on soil microbial enzymatic activities (phosphatase, dehydrogenase) were observed. The effects on soil microorganism were observed earlier but then recovered in systems with manure co-addition. More important, OTC related plant inhibition was observed in the manured but not in the non-manured systems. Oxytetracycline reached 0.19 and 1.85 mg/l in the leachate of the soil spiked with 1 and 100 mg OTC/kg, respectively and 0.05 and 1.14 mg/l for the same OTC concentrations in the manured systems. The results confirm that manure can modify both the fate and the effects of OTC and that the multi-species-soil systems can reproduce the conditions for a realistic effect estimation of veterinary medicines.

  3. A TDR-Based Soil Moisture Monitoring System with Simultaneous Measurement of Soil Temperature and Electrical Conductivity

    PubMed Central

    Skierucha, Wojciech; Wilczek, Andrzej; Szypłowska, Agnieszka; Sławiński, Cezary; Lamorski, Krzysztof

    2012-01-01

    Elements of design and a field application of a TDR-based soil moisture and electrical conductivity monitoring system are described with detailed presentation of the time delay units with a resolution of 10 ps. Other issues discussed include the temperature correction of the applied time delay units, battery supply characteristics and the measurement results from one of the installed ground measurement stations in the Polesie National Park in Poland. PMID:23202009

  4. Soil carbon storage in silvopastoral systems and a treeless pasture in northwestern Spain.

    PubMed

    Howlett, David S; Mosquera-Losada, M Rosa; Nair, P K Ramachandran; Nair, Vimala D; Rigueiro-Rodríguez, Antonio

    2011-01-01

    Soil particle size and land management practices are known to have considerable influence on carbon (C) storage in soils, but such information is lacking for silvopastoral systems in Spain. This study quantified the amounts of soil C stored at various depths to 100 cm under silvopastoral plots of radiata pine ( D. Don) and birch ( Roth) in comparison to treeless pasture in Galicia, Spain. Soils were fractionated into three size classes (<53, 53-250, and 250-2000 μm), and C stored in them and in the whole (nonfractionated) soil was determined. Overall, the C stock to 1 m ranged from 80.9 to 176.9 Mg ha in these soils. Up to 1 m depth, 78.82% of C was found in the 0- to 25-cm soil depth, with 12.9, 4.92, and 3.36% in the 25- to 50-, 50- to 75-, and 75- to 100-cm depths, respectively. Soils under birch at 0 to 25 cm stored more C in the 250- to 2000-μm size class as compared with those under radiata pine; at that depth, pasture had more C than pine silvopasture in the smaller soil fractions (<53 and 53-250 μm). In the 75- to 100-cm depth, there was significantly more storage of C in the 250- to 2000-μm fraction in both silvopastures as compared with the pasture. The higher storage of soil C in larger fraction size in lower soil depths of silvopasture suggests that planting of trees into traditional agricultural landscapes will promote longer-term storage of C in the soil. PMID:21546668

  5. Bioavailability and ecotoxicity of arsenic species in solution culture and soil system: implications to remediation.

    PubMed

    Bolan, Nanthi; Mahimairaja, Santiago; Kunhikrishnan, Anitha; Seshadri, Balaji; Thangarajan, Ramya

    2015-06-01

    In this work, bioavailability and ecotoxicity of arsenite (As(III)) and arsenate (As(V)) species were compared between solution culture and soil system. Firstly, the adsorption of As(III) and As(V) was compared using a number of non-allophanic and allophanic soils. Secondly, the bioavailability and ecotoxicity were examined using germination, phytoavailability, earthworm, and soil microbial activity tests. Both As-spiked soils and As-contaminated sheep dip soils were used to test bioavailability and ecotoxicity. The sheep dip soil which contained predominantly As(V) species was subject to flooding to reduce As(V) to As(III) and then used along with the control treatment soil to compare the bioavailability between As species. Adsorption of As(V) was much higher than that of As(III), and the difference in adsorption between these two species was more pronounced in the allophanic than non-allophanic soils. In the solution culture, there was no significant difference in bioavailability and ecotoxicity, as measured by germination and phytoavailability tests, between these two As species. Whereas in the As-spiked soils, the bioavailability and ecotoxicity were higher for As(III) than As(V), and the difference was more pronounced in the allophanic than non-allophanic soils. Bioavailability of As increased with the flooding of the sheep dip soils which may be attributed to the reduction of As(V) to As(III) species. The results in this study have demonstrated that while in solution, the bioavailability and ecotoxicity do not vary between As(III) and As(V), in soils, the latter species is less bioavailable than the former species because As(V) is more strongly retained than As(III). Since the bioavailability and ecotoxicity of As depend on the nature of As species present in the environment, risk-based remediation approach should aim at controlling the dynamics of As transformation.

  6. Crop diversification, tillage, and management system influences on spring wheat yield and soil water use

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Depleted soil quality, decreased water availability, and increased weed competition constrain spring wheat production in the northern Great Plains. Integrated crop management systems are necessary for improved crop productivity. We conducted a field experiment from 2004-2010 comparing productivity...

  7. METAL SPECIATION IN SOIL, SEDIMENT, AND WATER SYSTEMS VIA SYNCHROTRON RADIATION RESEARCH

    EPA Science Inventory

    Metal contaminated environmental systems (soils, sediments, and water) have challenged researchers for many years. Traditional methods of analysis have employed extraction methods to determine total metal content and define risk based on the premise that as metal concentration in...

  8. Heavy Metal Pollution in a Soil-Rice System in the Yangtze River Region of China.

    PubMed

    Liu, Zhouping; Zhang, Qiaofen; Han, Tiqian; Ding, Yanfei; Sun, Junwei; Wang, Feijuan; Zhu, Cheng

    2016-01-01

    Heavy metals are regarded as toxic trace elements in the environment. Heavy metal pollution in soil or rice grains is of increasing concern. In this study, 101 pairs of soil and rice samples were collected from the major rice-producing areas along the Yangtze River in China. The soil properties and heavy metal (i.e., Cd, Hg, Pb and Cr) concentrations in the soil and rice grains were analyzed to evaluate the heavy metal accumulation characteristics of the soil-rice systems. The results showed that the Cd, Hg, Pb and Cr concentrations in the soil ranged from 0.10 to 4.64, 0.01 to 1.46, 7.64 to 127.56, and 13.52 to 231.02 mg·kg(-)¹, respectively. Approximately 37%, 16%, 60% and 70% of the rice grain samples were polluted by Cd, Hg, Pb, and Cr, respectively. The degree of heavy metal contamination in the soil-rice systems exhibited a regional variation. The interactions among the heavy metal elements may also influence the migration and accumulation of heavy metals in soil or paddy rice. The accumulation of heavy metals in soil and rice grains is related to a certain extent to the pH and soil organic matter (SOM). This study provides useful information regarding heavy metal accumulation in soil to support the safe production of rice in China. The findings from this study also provide a robust scientific basis for risk assessments regarding ecological protection and food safety. PMID:26703698

  9. Heavy Metal Pollution in a Soil-Rice System in the Yangtze River Region of China

    PubMed Central

    Liu, Zhouping; Zhang, Qiaofen; Han, Tiqian; Ding, Yanfei; Sun, Junwei; Wang, Feijuan; Zhu, Cheng

    2015-01-01

    Heavy metals are regarded as toxic trace elements in the environment. Heavy metal pollution in soil or rice grains is of increasing concern. In this study, 101 pairs of soil and rice samples were collected from the major rice-producing areas along the Yangtze River in China. The soil properties and heavy metal (i.e., Cd, Hg, Pb and Cr) concentrations in the soil and rice grains were analyzed to evaluate the heavy metal accumulation characteristics of the soil-rice systems. The results showed that the Cd, Hg, Pb and Cr concentrations in the soil ranged from 0.10 to 4.64, 0.01 to 1.46, 7.64 to 127.56, and 13.52 to 231.02 mg·kg−1, respectively. Approximately 37%, 16%, 60% and 70% of the rice grain samples were polluted by Cd, Hg, Pb, and Cr, respectively. The degree of heavy metal contamination in the soil-rice systems exhibited a regional variation. The interactions among the heavy metal elements may also influence the migration and accumulation of heavy metals in soil or paddy rice. The accumulation of heavy metals in soil and rice grains is related to a certain extent to the pH and soil organic matter (SOM). This study provides useful information regarding heavy metal accumulation in soil to support the safe production of rice in China. The findings from this study also provide a robust scientific basis for risk assessments regarding ecological protection and food safety. PMID:26703698

  10. Heavy Metal Pollution in a Soil-Rice System in the Yangtze River Region of China.

    PubMed

    Liu, Zhouping; Zhang, Qiaofen; Han, Tiqian; Ding, Yanfei; Sun, Junwei; Wang, Feijuan; Zhu, Cheng

    2015-12-22

    Heavy metals are regarded as toxic trace elements in the environment. Heavy metal pollution in soil or rice grains is of increasing concern. In this study, 101 pairs of soil and rice samples were collected from the major rice-producing areas along the Yangtze River in China. The soil properties and heavy metal (i.e., Cd, Hg, Pb and Cr) concentrations in the soil and rice grains were analyzed to evaluate the heavy metal accumulation characteristics of the soil-rice systems. The results showed that the Cd, Hg, Pb and Cr concentrations in the soil ranged from 0.10 to 4.64, 0.01 to 1.46, 7.64 to 127.56, and 13.52 to 231.02 mg·kg(-)¹, respectively. Approximately 37%, 16%, 60% and 70% of the rice grain samples were polluted by Cd, Hg, Pb, and Cr, respectively. The degree of heavy metal contamination in the soil-rice systems exhibited a regional variation. The interactions among the heavy metal elements may also influence the migration and accumulation of heavy metals in soil or paddy rice. The accumulation of heavy metals in soil and rice grains is related to a certain extent to the pH and soil organic matter (SOM). This study provides useful information regarding heavy metal accumulation in soil to support the safe production of rice in China. The findings from this study also provide a robust scientific basis for risk assessments regarding ecological protection and food safety.

  11. Solvent extraction of PCB-contaminated soils using the Terra-Kleen system

    SciTech Connect

    Engle, S.W.; Kosco, B.; Cash, A.; Meckes, M.

    1994-12-31

    Removal of polychlorinated biphenyls (PCB) from soils has been difficult to implement on a full-scale, cost-effective basis. The Terra-Kleen solvent extraction system has overcome many of the soil handling, contaminant removal, and regulatory restrictions which have made implementing a cost-effective PCB soil treatment system difficult. The Terra-Kleen system uses a proprietary solvent to extract organic contaminants from soils. This batch process operates at ambient temperatures and employs a solvent regeneration system which concentrates the extracted contaminants and permits reuse of the extraction solvent. Following treatment, the treatment soils are returned to the land, and concentrated contaminant is removed off site for disposal. Terra-Kleen demonstrated the technology during a treatability study in October 1993 and a pilot-scale demonstration in May 1994. In October 1993, PRC obtained 1-ton batches of soil from each of three PCB-contaminated sites and shipped them to Terra-Kleen`s testing facility in Okmulgee, Oklahoma. Two sites were located at Naval Air Station North Island (NASNI) near San Diego, California. The third site was located in Anchorage, Alaska. Analysis of all demonstration soils revealed that Aroclor 1260 was the only PCB mixture present. Successful removal of PCBs below target treatment levels during the treatability study lead to a pilot-scale demonstration in May 1994 at NASNI.

  12. Critical carbon input to maintain current soil organic carbon stocks in global wheat systems

    PubMed Central

    Wang, Guocheng; Luo, Zhongkui; Han, Pengfei; Chen, Huansheng; Xu, Jingjing

    2016-01-01

    Soil organic carbon (SOC) dynamics in croplands is a crucial component of global carbon (C) cycle. Depending on local environmental conditions and management practices, typical C input is generally required to reduce or reverse C loss in agricultural soils. No studies have quantified the critical C input for maintaining SOC at global scale with high resolution. Such information will provide a baseline map for assessing soil C dynamics under potential changes in management practices and climate, and thus enable development of management strategies to reduce C footprint from farm to regional scales. We used the soil C model RothC to simulate the critical C input rates needed to maintain existing soil C level at 0.1° × 0.1° resolution in global wheat systems. On average, the critical C input was estimated to be 2.0 Mg C ha−1 yr−1, with large spatial variability depending on local soil and climatic conditions. Higher C inputs are required in wheat system of central United States and western Europe, mainly due to the higher current soil C stocks present in these regions. The critical C input could be effectively estimated using a summary model driven by current SOC level, mean annual temperature, precipitation, and soil clay content. PMID:26759192

  13. Critical carbon input to maintain current soil organic carbon stocks in global wheat systems.

    PubMed

    Wang, Guocheng; Luo, Zhongkui; Han, Pengfei; Chen, Huansheng; Xu, Jingjing

    2016-01-01

    Soil organic carbon (SOC) dynamics in croplands is a crucial component of global carbon (C) cycle. Depending on local environmental conditions and management practices, typical C input is generally required to reduce or reverse C loss in agricultural soils. No studies have quantified the critical C input for maintaining SOC at global scale with high resolution. Such information will provide a baseline map for assessing soil C dynamics under potential changes in management practices and climate, and thus enable development of management strategies to reduce C footprint from farm to regional scales. We used the soil C model RothC to simulate the critical C input rates needed to maintain existing soil C level at 0.1° × 0.1° resolution in global wheat systems. On average, the critical C input was estimated to be 2.0 Mg C ha(-1) yr(-1), with large spatial variability depending on local soil and climatic conditions. Higher C inputs are required in wheat system of central United States and western Europe, mainly due to the higher current soil C stocks present in these regions. The critical C input could be effectively estimated using a summary model driven by current SOC level, mean annual temperature, precipitation, and soil clay content. PMID:26759192

  14. The behavior and toxicological effects of decabromodiphenyl ether (BDE209) in a soil-earthworm system.

    PubMed

    Zhang, Wei; Li, Jing; Liu, Kou; Lin, Kuangfei

    2015-12-15

    Decabromodiphenyl ether (BDE209) is easily absorbed by soil particles but barely degraded over time. Its potential ecological risk has received extensive attention. Here we supplemented natural soil with three different levels of BDE209 (1, 10 and 100 mg kg(-1) dry weight (i.e., dw)) to focus on the behavior and toxicological effects of BDE209 in a soil-earthworm system. Results demonstrated that earthworms accumulated BDE209 quickly, followed by biphasic elimination. The uptake rate constant (ku) values ranged from 0.156 to 0.232 mg soil kg(-1)worm d(-1), while the depuration rate (kd) values ranged from 0.228 to 0.239 d(-1). Biota-soil accumulation factor (BSAF) was also calculated in the present study, and the BSAF values for BDE209 ranged from 0.074 to 0.123. Throughout 28-d exposure, the concentrations of BDE209 among soil, worm casts and earthworms reached steady-state equilibrium. BDE209 content in worm casts might be a good indicator of actual concentration in soil. Neutral red retention time (NRRT) was also conducted to assess the lysosomal membrane stability, and it declined during the uptake phase when BDE209 gradually accumulated in earthworms, indicating a good dose-response relationship. These observations provide new insights into the potential ecological effects of BDE209 in a model soil-earthworm system.

  15. Critical carbon input to maintain current soil organic carbon stocks in global wheat systems

    NASA Astrophysics Data System (ADS)

    Wang, Guocheng; Luo, Zhongkui; Han, Pengfei; Chen, Huansheng; Xu, Jingjing

    2016-01-01

    Soil organic carbon (SOC) dynamics in croplands is a crucial component of global carbon (C) cycle. Depending on local environmental conditions and management practices, typical C input is generally required to reduce or reverse C loss in agricultural soils. No studies have quantified the critical C input for maintaining SOC at global scale with high resolution. Such information will provide a baseline map for assessing soil C dynamics under potential changes in management practices and climate, and thus enable development of management strategies to reduce C footprint from farm to regional scales. We used the soil C model RothC to simulate the critical C input rates needed to maintain existing soil C level at 0.1° × 0.1° resolution in global wheat systems. On average, the critical C input was estimated to be 2.0 Mg C ha‑1 yr‑1, with large spatial variability depending on local soil and climatic conditions. Higher C inputs are required in wheat system of central United States and western Europe, mainly due to the higher current soil C stocks present in these regions. The critical C input could be effectively estimated using a summary model driven by current SOC level, mean annual temperature, precipitation, and soil clay content.

  16. Critical carbon input to maintain current soil organic carbon stocks in global wheat systems

    NASA Astrophysics Data System (ADS)

    Wang, Guocheng; Luo, Zhongkui; Han, Pengfei; Chen, Huansheng; Xu, Jingjing

    2016-01-01

    Soil organic carbon (SOC) dynamics in croplands is a crucial component of global carbon (C) cycle. Depending on local environmental conditions and management practices, typical C input is generally required to reduce or reverse C loss in agricultural soils. No studies have quantified the critical C input for maintaining SOC at global scale with high resolution. Such information will provide a baseline map for assessing soil C dynamics under potential changes in management practices and climate, and thus enable development of management strategies to reduce C footprint from farm to regional scales. We used the soil C model RothC to simulate the critical C input rates needed to maintain existing soil C level at 0.1° × 0.1° resolution in global wheat systems. On average, the critical C input was estimated to be 2.0 Mg C ha-1 yr-1, with large spatial variability depending on local soil and climatic conditions. Higher C inputs are required in wheat system of central United States and western Europe, mainly due to the higher current soil C stocks present in these regions. The critical C input could be effectively estimated using a summary model driven by current SOC level, mean annual temperature, precipitation, and soil clay content.

  17. Complexity in Soil Systems: What Does It Mean and How Should We Proceed?

    NASA Astrophysics Data System (ADS)

    Faybishenko, B.; Molz, F. J.; Brodie, E.; Hubbard, S. S.

    2015-12-01

    The complex soil systems approach is needed fundamentally for the development of integrated, interdisciplinary methods to measure and quantify the physical, chemical and biological processes taking place in soil, and to determine the role of fine-scale heterogeneities. This presentation is aimed at a review of the concepts and observations concerning complexity and complex systems theory, including terminology, emergent complexity and simplicity, self-organization and a general approach to the study of complex systems using the Weaver (1948) concept of "organized complexity." These concepts are used to provide understanding of complex soil systems, and to develop experimental and mathematical approaches to soil microbiological processes. The results of numerical simulations, observations and experiments are presented that indicate the presence of deterministic chaotic dynamics in soil microbial systems. So what are the implications for the scientists who wish to develop mathematical models in the area of organized complexity or to perform experiments to help clarify an aspect of an organized complex system? The modelers have to deal with coupled systems having at least three dependent variables, and they have to forgo making linear approximations to nonlinear phenomena. The analogous rule for experimentalists is that they need to perform experiments that involve measurement of at least three interacting entities (variables depending on time, space, and each other). These entities could be microbes in soil penetrated by roots. If a process being studied in a soil affects the soil properties, like biofilm formation, then this effect has to be measured and included. The mathematical implications of this viewpoint are examined, and results of numerical solutions to a system of equations demonstrating deterministic chaotic behavior are also discussed using time series and the 3D strange attractors.

  18. Thin soil layer of green roof systems studied by X-Ray CT

    NASA Astrophysics Data System (ADS)

    Šácha, Jan; Jelínková, Vladimíra; Dohnal, Michal

    2016-04-01

    The popular non-invasive visualization technique of X-ray computed tomography (CT) has been used for 3D examination of thin soil layer of vegetated roof systems. The two categories of anthropogenic soils, usually used for green roof systems, were scanned during the first months after green roof system construction. First was represented by stripped topsoil with admixed crushed bricks and was well graded in terms of particle size distribution. The other category represented a commercial lightweight technogenic substrate. The undisturbed soil samples of total volume of 62.8 ccm were studied be means of X-ray Computed Tomography using X-ray Inspection System GE Phoenix Nanomex 180T with resulting spatial resolution about 57 μm in all directions. For both soil categories visible macroporosity, connectivity (described by the Euler characteristic), dimensionless connectivity and critical cross section of pore network were determined. Moreover, the temporal structural changes of studied soils were discussed together with heat and water regime of the green roof system. The analysis of CT images of anthropogenic soils was problematic due to the different X-ray attenuation of individual constituents. The correct determination of the threshold image intensity differentiating the soil constituents from the air phase had substantial importance for soil pore network analyses. However, X-ray CT derived macroporosity profiles reveal significant temporal changes notably in the soil comprised the stripped topsoil with admixed crushed bricks. The results implies that the technogenic substrate is structurally more stable over time compared to the stripped topsoil. The research was realized as a part of the University Centre for Energy Efficient Buildings supported by the EU and with financial support from the Czech Science Foundation under project number 14-10455P.

  19. Soil management system for water conservation and mitigation of global change effect

    NASA Astrophysics Data System (ADS)

    Ospina, A.; Florentino, A.; Lorenzo, V.

    2012-04-01

    One of the main constraints in rained agriculture is the water availability for plant growth which depends largely on the ability of the soil to allow water flow, infiltration and its storage. In Venezuela, the interaction between aggressive climatic conditions, highly susceptible soils and inadequate management systems have caused soil degradation which together with global change threatened the food production sustainability. To address this problem, we need to implement conservationist management strategies that improve infiltration rate, permeability and water holding capacity in soil and reduce water loss by protecting the soil surface. In order to study the impact of different management systems on soil water balance in a Fluventic Haplustept, the effects of 11 years of tillage and crops rotation management were evaluated in a long term field experiment located in Turén (Portuguesa state). The evaluated tillage systems were no tillage (NT) and conventional tillage (CT) and crop rotation treatments were maize (Zea mays)-cotton (Gossypium hirsutum) and maize-bean (Vigna unguiculata). Treatments were established in plots arranged in a randomized block design with three replicates. The gravimetric moisture content was determined in the upper 20 cm of soil, at eight different sampling dates. Results showed increased in time of the water availability with the use of tillage and corn-cotton rotation and, better protection of the soil against raindrop impact with crop residues. Water retention capacity also increased and improved structural condition on soil surface such as infiltration, storage and water flow distribution in the rooting zone. We conclude that these strategies of land use and management would contribute to mitigate the climate change effects on food production in this region of Venezuela. Key words: Soil quality; rained agriculture; plant water availability

  20. Nonstationarity of the electrical resistivity and soil moisture relationship in a heterogeneous soil system: a case study

    NASA Astrophysics Data System (ADS)

    Michot, Didier; Thomas, Zahra; Adam, Issifou

    2016-06-01

    Understanding the role of vegetation in the interface between the atmosphere and groundwater is the most decisive key in analyzing the processes involved in water transfer. The main effect of vegetation is its root water uptake, which significantly modifies the processes involved in water transfer in the vadose zone. This paper focuses on mapping temporal and spatial changes in soil moisture using electrical resistivity tomography (ERT). The main objective is to assess how electrical resistivity (ER) is useful for mapping water distribution along a heterogeneous toposequence crossed by a hedgerow. Ten ERT were performed over the studied period for a 28 m long toposequence and compared to matric potential and groundwater level measurements. Soil volumetric water content (VWC) was predicted with two methods: (i) from ER using the Waxman and Smits model (ii) and from matric potential using an experimental retention curve fitted by a Van Genuchten model. Probability density functions (PDFs) of our set of data show that the largest change in mean ER and matric potential was observed in the topsoil layer. We then analyzed the consistency between ER and point measurements in this layer by extracting the arrays at the junction of ER grids and point measurements. PDFs of ER maps at each monitoring time (from T01 to T10) were also calculated to select the most contrasting distributions, corresponding to the wettest (T06) and driest states (T10). Results of ER were consistent with matric-potential measurements, with two different behaviors for locations inside and outside the root zone. A consistent correlation between VWC values from the Waxman and Smits model and those obtained from the retention curve was observed outside the root zone. The heterogeneous soil system inside the root zone shows a different pattern in this relationship. A shift in the relationship between ER and soil moisture for the locations outside and inside the root zone highlights the nonstationarity

  1. Performance of a soil vapor extraction system for VOC removal at a National Priorities List site

    SciTech Connect

    Aggarwal, P.K.; Hansen, M.C.; Kickels, W.T.

    1994-12-31

    A combined soil vapor and groundwater extraction system has been operating at the Waverly, Nebraska, National Priorities List site for the past six years. Combined soil gas concentrations of carbon tetrachloride and chloroform were about 40,000 {micro}g/m{sup 3} at system startup. For the past two years, soil gas concentrations have ranged from about 2 to 900 {micro}g/m{sup 3}. The action level specified in the Record of Decision for system closure is 6.5 {micro}g/m{sup 3} for total carbon tetrachloride and chloroform. To evaluate the future performance of the vapor extraction system (VES) in achieving compliance with the action levels, soil gas sampling methods have been modified, and the system has been operated both continuously and with periods of temporary shutdown. Use of a Carbotrap sampling medium and a sampling flow rate sufficient to overcome the subsurface flow regime imposed by the VES eliminated large variations observed in soil gas contaminant concentrations. During a VES shutdown of two to six months, contaminant concentrations in the soil gas increased. These concentrations decreased within about 24 hr of restarting to the levels observed during continuous operation of the system. The future contaminant flux to groundwater from the source area can be estimated from the steady-state contaminant concentrations measured during VES operation and shutdown and the estimated recharge rates.

  2. Assimilation of Satellite Based Soil Moisture Data in the National Weather Service's Flash Flood Guidance System

    NASA Astrophysics Data System (ADS)

    Seo, D.; Lakhankar, T.; Cosgrove, B.; Khanbilvardi, R.

    2012-12-01

    Climate change and variability increases the probability of frequency, timing, intensity, and duration of flood events. After rainfall, soil moisture is the most important factor dictating flash flooding, since rainfall infiltration and runoff are based on the saturation of the soil. It is difficult to conduct ground-based measurements of soil moisture consistently and regionally. As such, soil moisture is often derived from models and agencies such as the National Oceanic and Atmospheric Administration's National Weather Service (NOAA/NWS) use proxy estimates of soil moisture at the surface in order support operational flood forecasting. In particular, a daily national map of Flash Flood Guidance (FFG) is produced that is based on surface soil moisture deficit and threshold runoff estimates. Flash flood warnings are issued by Weather Forecast Offices (WFOs) and are underpinned by information from the Flash Flood Guidance (FFG) system operated by the River Forecast Centers (RFCs). This study analyzes the accuracy and limitations of the FFG system using reported flash flood cases in 2010 and 2011. The flash flood reports were obtained from the NWS Storm Event database for the Arkansas-Red Basin RFC (ABRFC). The current FFG system at the ABRFC provides gridded flash flood guidance (GFFG) System using the NWS Hydrology Laboratory-Research Distributed Hydrologic Model (HL-RDHM) to translate the upper zone soil moisture to estimates of Soil Conservation Service Curve Numbers. Comparison of the GFFG and real-time Multi-sensor Precipitation Estimator derived Quantitative Precipitation Estimate (QPE) for the same duration and location were used to analyze the success of the system. Improved flash flood forecasting requires accurate and high resolution soil surface information. The remote sensing observations of soil moisture can improve the flood forecasting accuracy. The Soil Moisture Active and Passive (SMAP) and Soil Moisture and Ocean Salinity (SMOS) satellites are two

  3. Validation testing of a soil macronutrient sensing system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rapid on-site measurements of soil macronutrients (i.e., nitrogen, phosphorus, and potassium) are needed for site-specific crop management, where fertilizer nutrient application rates are adjusted spatially based on local requirements. This study reports on validation testing of a previously develop...

  4. Formation of organic iodine supplied as iodide in a soil-water system in Chiba, Japan.

    PubMed

    Shimamoto, Yoko S; Takahashi, Yoshio; Terada, Yasuko

    2011-03-15

    Speciation of iodine in a soil-water system was investigated to understand the mechanism of iodine mobility in surface environments. Iodine speciation in soil and pore water was determined by K-edge XANES and HPLC-ICP-MS, respectively, for samples collected at a depth of 0-12 cm in the Yoro area, Chiba, Japan. Pore water collected at a 0-6 cm depth contained 50%-60% of organic iodine bound to dissolved organic matter, with the other portion being I(-). At a 9-12 cm depth, 98% of iodine was in the form of dissolved I(-). In contrast, XANES analysis revealed that iodine in soil exists as organic iodine at all depths. Iodine mapping of soil grains was obtained using micro-XRF analysis, which also indicated that iodine is bound to organic matter. The activity of laccase, which has the ability to oxidize I(-) to I(2), was high at the surface of the soil-water layer, suggesting that iodide oxidizing enzymes can promote iodine organification. The distribution coefficient of organic iodine in the soil-water system was more than 10-fold greater than that of iodide. Transformation of inorganic iodine to organic iodine plays an important role in iodine immobilization, especially in a surface soil-water system.

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

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

  6. Carbon storage of different soil-size fractions in Florida silvopastoral systems.

    PubMed

    Haile, Solomon G; Nair, P K Ramachandran; Nair, Vimala D

    2008-01-01

    Compared with open (treeless) pasture systems, silvopastoral agroforestry systems that integrate trees into pasture production systems are likely to enhance soil carbon (C) sequestration in deeper soil layers. To test this hypothesis, total soil C contents at six soil depths (0-5, 5-15, 15-30, 30-50, 50-75, and 75-125 cm) were determined in silvopastoral systems with slash pine (Pinus elliottii) + bahiagrass (Paspalum notatum) and an adjacent open pasture (OP) with bahiagrass at four sites, representing Spodosols and Ultisols, in Florida. Soil samples from each layer were fractionated into three classes (250-2000, 53-250, and <53 microm), and the C contents in each were determined. Averaged across four sites and all depths, the total soil organic carbon (SOC) content was higher by 33% in silvopastures near trees (SP-T) and by 28% in the alleys between tree rows (SP-A) than in adjacent open pastures. It was higher by 39% in SP-A and 20% in SP-T than in open pastures in the largest fraction size (250-2000 microm) and by 12.3 and 18.8%, respectively, in the intermediate size fraction (53-250 microm). The highest SOC increase (up to 45 kg m(-2)) in whole soil of silvopasture compared with OP was at the 75- to 125-cm depth at the Spodosol sites. The results support the hypothesis that, compared with open pastures, silvopastures contain more C in deeper soil layers under similar ecological settings, possibly as a consequence of a major input to soil organic matter from decomposition of dead tree-roots. PMID:18689740

  7. Effects of crop residue on soil and plant water evaporation in a dryland cotton system

    NASA Astrophysics Data System (ADS)

    Lascano, R. J.; Baumhardt, R. L.

    1996-03-01

    Dryland agricultural cropping systems emphasize sustaining crop yields with limited use of fertilizer while conserving both rain water and the soil. Conservation of these resources may be achieved with management systems that retain residues at the soil surface simultaneously modifying both its energy and water balance. A conservation practice used with cotton grown on erodible soils of the Texas High Plains is to plant cotton into chemically terminated wheat residues. In this study, the partitioning of daily and seasonal evapotranspiration ( E t) into soil and plant water evaporation was compared for a conventional and a terminated-wheat cotton crop using the numerical model ENWATBAL. The model was configured to account for the effects of residue on the radiative fluxes and by introducing an additional resistance to latent and sensible heat fluxes derived from measurements of wind speed and vapor conductance from a soil covered with wheat-stubble. Our results showed that seasonal E t was similar in both systems and that cumulative soil water evaporation was 50% of E t in conventional cotton and 31% of E t in the wheat-stubble cotton. Calculated values of E t were in agreement with measured values. The main benefit of the wheat residues was to suppress soil water evaporation by intercepting irradiance early in the growing season when the crop leaf area index (LAI) was low. In semiarid regions LAI of dryland cotton seldom exceeds 2 and residues can improve water conservation. Measured soil temperatures showed that early in the season residues reduced temperature at 0.1 m depth by as much as 5°C and that differences between systems diminished with depth and over time. Residues increased lint yield per unit of E t while not modifying seasonal E t and reducing cumulative soil water evaporation.

  8. Soil carbon storage in silvopasture and related land-use systems in the brazilian cerrado.

    PubMed

    Tonucci, Rafael G; Nair, P K Ramachandran; Nair, Vimala D; Garcia, Rasmo; Bernardino, Fernando S

    2011-01-01

    Silvopastoral management of fast-growing tree plantations is becoming popular in the Brazilian Cerrado (savanna). To understand the influence of such systems on soil carbon (C) storage, we studied C content in three aggregate size classes in six land-use systems (LUS) on Oxisols in Minas Gerais, Brazil. The systems were a native forest, a treeless pasture, 24- and 4-yr-old eucalyptus ( sp.) plantations, and 15- and 4-yr-old silvopastures of fodder grass plus animals under eucalyptus. From each system, replicated soil samples were collected from four depths (0-10, 10-20, 20-50, and 50-100 cm), fractionated into 2000- to 250-, 250- to 53-, and <53-μm size classes representing macroaggregates, microaggregates, and silt + clay, respectively, and their C contents determined. Macroaggregate was the predominant size fraction under all LUS, especially in the surface soil layers of tree-based systems. In general, C concentrations (g kg soil) in the different aggregate size fractions did not vary within the same depth. The soil organic carbon (SOC) stock (Mg C ha) to 1-m depth was highest under pasture compared with other LUS owing to its higher soil bulk density. The soils under all LUS had higher C stock compared with other reported values for managed tropical ecosystems: down to 1 m, total SOC stock values ranged from 461 Mg ha under pasture to 393 Mg ha under old eucalyptus. Considering the possibility for formation and retention of microaggregates within macroggregates in low management-intensive systems such as silvopasture, the macroaggregate dynamics in the soil seem to be a good indicator of its C storage potential. PMID:21546669

  9. Soil carbon storage in silvopasture and related land-use systems in the brazilian cerrado.

    PubMed

    Tonucci, Rafael G; Nair, P K Ramachandran; Nair, Vimala D; Garcia, Rasmo; Bernardino, Fernando S

    2011-01-01

    Silvopastoral management of fast-growing tree plantations is becoming popular in the Brazilian Cerrado (savanna). To understand the influence of such systems on soil carbon (C) storage, we studied C content in three aggregate size classes in six land-use systems (LUS) on Oxisols in Minas Gerais, Brazil. The systems were a native forest, a treeless pasture, 24- and 4-yr-old eucalyptus ( sp.) plantations, and 15- and 4-yr-old silvopastures of fodder grass plus animals under eucalyptus. From each system, replicated soil samples were collected from four depths (0-10, 10-20, 20-50, and 50-100 cm), fractionated into 2000- to 250-, 250- to 53-, and <53-μm size classes representing macroaggregates, microaggregates, and silt + clay, respectively, and their C contents determined. Macroaggregate was the predominant size fraction under all LUS, especially in the surface soil layers of tree-based systems. In general, C concentrations (g kg soil) in the different aggregate size fractions did not vary within the same depth. The soil organic carbon (SOC) stock (Mg C ha) to 1-m depth was highest under pasture compared with other LUS owing to its higher soil bulk density. The soils under all LUS had higher C stock compared with other reported values for managed tropical ecosystems: down to 1 m, total SOC stock values ranged from 461 Mg ha under pasture to 393 Mg ha under old eucalyptus. Considering the possibility for formation and retention of microaggregates within macroggregates in low management-intensive systems such as silvopasture, the macroaggregate dynamics in the soil seem to be a good indicator of its C storage potential.

  10. [Effect of silicon on translocation and morphology distribution of lead in soil-tobacco system].

    PubMed

    Yan, Yi-Hua; Zheng, Zi-Cheng; Li, Ting-Xuan; Zhang, Xi-Zhou; Wang, Yong

    2014-10-01

    Taking tobacco as test material, a pot experiment was conducted to study the effect of silicon on translocation of lead (Pb) form soil to tobacco in order to explore effective measures for reducing Pb concentration in tobacco leaf. The results showed that silicon application promoted the transformation of exchangeable Pb into Fe-Mn oxide-bound Pb in non-rhizospheric soil, and into Fe-Mn oxide-bound Pb and residual Pb in rhizospheric soil, which decreased the availability and mobility of Pb in the soil. Silicon application significantly reduced the Pb uptake of tobacco, with the content of Pb being decreased by 6.5% to 44.0% in tobacco, and 3.1% to 60.4% in leaf. Silicon application promoted the transformation of ethanol-extractable, H2O-extractable Pb and NaCl-extractable Pb into HCl-extractable Pb and residual Pb in root, stem and leaf of tobacco, which reduced the toxicity and mobility of Pb in tobacco. Silicon restricted the transportation of Pb from soil to tobacco leaf by reducing the mobility index of Pb from soil to root and the mobility index of Pb from root to stem in soil-tobacco system. Meanwhile, the mobility index of Pb from stem to leaf in soil-tobacco system showed a rising-and-falling trend with the increase of Pb application. Silicon inhibited the Pb migration from soil to tobacco leaf by reducing availability of Pb, mitigating toxicity of Pb to tobacco, and changing the distribution of Pb forms in tobacco, consequently reducing Pb concentration of tobacco leaf. These results demonstrated silicon application could be effective in reducing translocation of Pb from soil to tobacco.

  11. Development of a differential volume reactor system for soil biodegradation studies

    SciTech Connect

    Webb, O.F.; Bienkowski, P.R.; Reed, G.D.

    1991-12-31

    A bench scale experimental system was developed for the analysis of polycyclic aromatic hydrocarbon (PAH) degradation by mixed microbial cultures in PAH contaminated Manufactured Gas Plant (MGP) soils and on sand. The reactor system was chosen in order to provide a fundamental protocol capable for evaluating the performance of specific mixed microbial cultures on specific soil systems by elucidating the important system variables and their interactions. The reactor design and peripherals are described. A plug flow differential volume reactor (DVR) was used in order to remove performance effects related to reactor type, as opposed to system structure. This reactor system could be well represented mathematically. Methods were developed for on-line quantitative determination of PAH liquid phase concentrations. The mathematical models and experimental data are presented for the biodegradation of naphthalene on artificial and MGP soils.

  12. Development of a differential volume reactor system for soil biodegradation studies.

    PubMed

    Webb, O F; Phelps, T J; Bienkowski, P R; DiGrazia, P M; Reed, G D; Applegate, B; White, D C; Sayler, G S

    1991-01-01

    A bench scale experimental system was developed for the analysis of polycyclic aromatic hydrocarbon (PAH) degradation by mixed microbial cultures in PAH contaminated Manufactured Gas Plant (MGP) soils and on sand. The reactor system was chosen in order to provide a fundamental protocol capable for evaluating the performance of specific mixed microbial cultures on specific soil systems by elucidating the important system variables and their interactions. The reactor design and peripherals are described. A plug flow differential volume reactor (DVR) was used in order to remove performance effects related to reactor type, as opposed to system structure. This reactor system could be well represented mathematically. Methods were developed for on-line quantitative determination of PAH liquid phase concentrations. The mathematical models and experimental data are presented for the biodegradation of naphthalene on artificial and MGP soils.

  13. [Residue and Degradation of Roxarsone in the System of Soil-Vegetable].

    PubMed

    Shao, Ting; Yao, Chun-xia; Shen, Yuan-yuan; Zhang, Yu-jie; Su, Nan-nan; Zhou, Shou-biao

    2015-08-01

    The field experiment was developed for simulating the residues, transformation and degradation in soil-vegetable system of Roxarsone contained in organic fertilizer. Under the treatment, the yield of Brassica chinensis decreased in low Roxarsone concentration with a decline by 15% to 32% compared with the control group; there had an accumulating role of vegetables to arsenic, and the root was the main part; total content of arsenic in the soil was positively correlated with the dose of the applied Roxarsone; total arsenic in soil first increased and then decreased with the planting time prolonged and peaked at 12.94 mg x kg(-1), while the level of inorganic arsenic in the soil stabilized after 30 d, which accounting for 66.75% to 98.56% of the total arsenic; there existed a positively significant correlation of total arsenic content between the Brassica chinensis and the soil as well as the arsenic enrichment factor of vegetables; the degradation rate of Roxarsone in soil was slow, there was still some Roxarsone remained in soil after 45 d when added the organic fertilizer which containing Roxarsone with the dose higher than 5 000 kg x hm(-2); Roxarsone could significantly increase the number of bacteria in the soil, and low concentration showed an inhibited role in the growth of fungi and actinomyces, while high concentration of Roxarsone promoted the growth. PMID:26592042

  14. Intercropped silviculture systems, a key to achieving soil fungal community management in eucalyptus plantations

    DOE PAGES

    Caio T.C.C. Rachid; Balieiro, Fabiano C.; Fonseca, Eduardo S.; Peixoto, Raquel Silva; Chaer, Guilherme M.; Tiedje, James M.; Rosado, Alexandre S.

    2015-02-23

    Fungi are ubiquitous and important contributors to soil nutrient cycling, playing a vital role in C, N and P turnover, with many fungi having direct beneficial relationships with plants. However, the factors that modulate the soil fungal community are poorly understood. We studied the degree to which the composition of tree species affected the soil fungal community structure and diversity by pyrosequencing the 28S rRNA gene in soil DNA. We were also interested in whether intercropping (mixed plantation of two plant species) could be used to select fungal species. More than 50,000 high quality sequences were analyzed from three treatments:more » monoculture of Eucalyptus; monoculture of Acacia mangium; and a mixed plantation with both species sampled 2 and 3 years after planting. We found that the plant type had a major effect on the soil fungal community structure, with 75% of the sequences from the Eucalyptus soil belonging to Basidiomycota and 19% to Ascomycota, and the Acacia soil having a sequence distribution of 28% and 62%, respectively. The intercropping of Acacia mangium in a Eucalyptus plantation significantly increased the number of fungal genera and the diversity indices and introduced or increased the frequency of several genera that were not found in the monoculture cultivation samples. Our results suggest that management of soil fungi is possible by manipulating the composition of the plant community, and intercropped systems can be a means to achieve that.« less

  15. Intercropped silviculture systems, a key to achieving soil fungal community management in eucalyptus plantations

    SciTech Connect

    Caio T.C.C. Rachid; Balieiro, Fabiano C.; Fonseca, Eduardo S.; Peixoto, Raquel Silva; Chaer, Guilherme M.; Tiedje, James M.; Rosado, Alexandre S.

    2015-02-23

    Fungi are ubiquitous and important contributors to soil nutrient cycling, playing a vital role in C, N and P turnover, with many fungi having direct beneficial relationships with plants. However, the factors that modulate the soil fungal community are poorly understood. We studied the degree to which the composition of tree species affected the soil fungal community structure and diversity by pyrosequencing the 28S rRNA gene in soil DNA. We were also interested in whether intercropping (mixed plantation of two plant species) could be used to select fungal species. More than 50,000 high quality sequences were analyzed from three treatments: monoculture of Eucalyptus; monoculture of Acacia mangium; and a mixed plantation with both species sampled 2 and 3 years after planting. We found that the plant type had a major effect on the soil fungal community structure, with 75% of the sequences from the Eucalyptus soil belonging to Basidiomycota and 19% to Ascomycota, and the Acacia soil having a sequence distribution of 28% and 62%, respectively. The intercropping of Acacia mangium in a Eucalyptus plantation significantly increased the number of fungal genera and the diversity indices and introduced or increased the frequency of several genera that were not found in the monoculture cultivation samples. Our results suggest that management of soil fungi is possible by manipulating the composition of the plant community, and intercropped systems can be a means to achieve that.

  16. A land data assimilation system for simultaneous simulation of soil moisture and vegetation dynamics

    NASA Astrophysics Data System (ADS)

    Sawada, Yohei; Koike, Toshio; Walker, Jeffrey P.

    2015-06-01

    Despite the importance of the coupling between vegetation dynamics and root-zone soil moisture in land-atmosphere interactions, there is no land data assimilation system (LDAS) that currently addresses this issue, limiting the capacity to positively impact weather and seasonal forecasting. We develop a new LDAS that can improve the skill of an ecohydrological model to simulate simultaneously surface soil moisture, root-zone soil moisture, and vegetation dynamics by assimilating passive microwave observations that are sensitive to both surface soil moisture and terrestrial biomass. This LDAS first calibrates both hydrological and ecological parameters of a land surface model, which explicitly simulates vegetation growth and senescence. Then, it adjusts the model states of soil moisture and leaf area index (LAI) sequentially using a genetic particle filter. We can adjust the subsurface soil moisture, which is not observed directly by satellites, because we simulate the interactions between vegetation dynamics and subsurface water dynamics. From a point-scale evaluation, we succeed in improving the performance of our land surface model and generate ensembles of the model state whose distribution reflects the combined information in the land surface model and satellite observations. We show that the adjustment of the subsurface soil moisture significantly improves the capacity to simulate vegetation dynamics in seasonal forecast timescales. This LDAS can contribute to the generation of ensemble initial conditions of surface and subsurface soil moisture and LAI for a probabilistic framework of weather and seasonal forecasting.

  17. Intercropped Silviculture Systems, a Key to Achieving Soil Fungal Community Management in Eucalyptus Plantations

    PubMed Central

    Rachid, Caio T. C. C.; Balieiro, Fabiano C.; Fonseca, Eduardo S.; Peixoto, Raquel Silva; Chaer, Guilherme M.; Tiedje, James M.; Rosado, Alexandre S.

    2015-01-01

    Fungi are ubiquitous and important contributors to soil nutrient cycling, playing a vital role in C, N and P turnover, with many fungi having direct beneficial relationships with plants. However, the factors that modulate the soil fungal community are poorly understood. We studied the degree to which the composition of tree species affected the soil fungal community structure and diversity by pyrosequencing the 28S rRNA gene in soil DNA. We were also interested in whether intercropping (mixed plantation of two plant species) could be used to select fungal species. More than 50,000 high quality sequences were analyzed from three treatments: monoculture of Eucalyptus; monoculture of Acacia mangium; and a mixed plantation with both species sampled 2 and 3 years after planting. We found that the plant type had a major effect on the soil fungal community structure, with 75% of the sequences from the Eucalyptus soil belonging to Basidiomycota and 19% to Ascomycota, and the Acacia soil having a sequence distribution of 28% and 62%, respectively. The intercropping of Acacia mangium in a Eucalyptus plantation significantly increased the number of fungal genera and the diversity indices and introduced or increased the frequency of several genera that were not found in the monoculture cultivation samples. Our results suggest that management of soil fungi is possible by manipulating the composition of the plant community, and intercropped systems can be a means to achieve that. PMID:25706388

  18. The Role of Soil Biological Function in Regulating Agroecosystem Services and Sustainability in the Quesungual Agroforestry System

    NASA Astrophysics Data System (ADS)

    Fonte, S.; Pauli, N.; Rousseau, L.; SIX, J. W. U. A.; Barrios, E.

    2014-12-01

    The Quesungual agroforestry system from western Honduras has been increasingly promoted as a promising alternative to traditional slash-and-burn agriculture in tropical dry forest regions of the Americas. Improved residue management and the lack of burning in this system can greatly impact soil biological functioning and a number of key soil-based ecosystem services, yet our understanding of these processes has not been thoroughly integrated to understand system functionality as a whole that can guide improved management. To address this gap, we present a synthesis of various field studies conducted in Central America aimed at: 1) quantifying the influence of the Quesungual agroforestry practices on soil macrofauna abundance and diversity, and 2) understanding how these organisms influence key soil-based ecosystem services that ultimately drive the success of this system. A first set of studies examined the impact of agroecosystem management on soil macrofauna populations, soil fertility and key soil processes. Results suggest that residue inputs (derived from tree biomass pruning), a lack of burning, and high tree densities, lead to conditions that support abundant, diverse soil macrofauna communities under agroforestry, with soil organic carbon content comparable to adjacent forest. Additionally, there is great potential in working with farmers to develop refined soil quality indicators for improved land management. A second line of research explored interactions between residue management and earthworms in the regulation of soil-based ecosystem services. Earthworms are the most prominent ecosystem engineers in these soils. We found that earthworms are key drivers of soil structure maintenance and the stabilization of soil organic matter within soil aggregates, and also had notable impacts on soil nutrient dynamics. However, the impact of earthworms appears to depend on residue management practices, thus indicating the need for an integrated approach for

  19. Raman Spectroscopy and instrumentation for monitoring soil carbon systems.

    SciTech Connect

    Stokes, D.L.

    2003-12-08

    This work describes developments in the application of Raman scattering and surface-enhanced Raman scattering (SERS) towards the assessment/characterization of carbon in soil. In the past, the nonspecific total carbon mass content of soil samples has generally been determined through mass loss techniques and elemental analysis. However, because of the concern over CO{sub 2} buildup in the atmosphere and its possible role in the ''Greenhouse Effect,'' there is a need for better-defined models of global cycling of carbon. As a means towards this end, there is a need to know more about the structure and functionality of organic materials in soil. Raman spectroscopy may therefore prove to be an exceptional tool in soil carbon analysis. Based on vibrational transitions of irradiated molecules, it provides structural information that is often suitable for sample identification. Furthermore, Raman scattering yields very fine spectral features which offer the potential for multicomponent sample analysis with minimal or no sample pretreatment. Although the intensity of Raman scattering is generally extremely low, the surface-enhanced Raman scattering (SERS) effect can greatly enhance Raman signals (10{sup 6}-10{sup 8} range) through the adsorption of compounds on specially roughened metal surfaces. In our laboratory, we have investigated copper, gold and silver as possible substrate metals in the fabrication of SERS substrates. These substrates have included metal-coated microparticles, metal island films, and redox-roughened metal foils. We have evaluated several laser excitation sources spanning the 515-785 nm range for both Raman and SERS analysis. For this particular study, we have selected fulvic and humic acids as models for establishing the feasibility of using Raman and SERS in soil carbon analysis. Our studies thus far have demonstrated that copper substrates perform best in the SERS detection of humic and fulvic acids, particularly when coupled to electrochemical

  20. Ecopiling: a combined phytoremediation and passive biopiling system for remediating hydrocarbon impacted soils at field scale.

    PubMed

    Germaine, Kieran J; Byrne, John; Liu, Xuemei; Keohane, Jer; Culhane, John; Lally, Richard D; Kiwanuka, Samuel; Ryan, David; Dowling, David N

    2014-01-01

    Biopiling is an ex situ bioremediation technology that has been extensively used for remediating a wide range of petrochemical contaminants in soils. Biopiling involves the assembling of contaminated soils into piles and stimulating the biodegrading activity of microbial populations by creating near optimum growth conditions. Phytoremediation is another very successful bioremediation technique and involves the use of plants and their associated microbiomes to degrade, sequester or bio-accumulate pollutants from contaminated soil and water. The objective of this study was to investigate the effectiveness of a combined phytoremediation/biopiling system, termed Ecopiling, to remediate hydrocarbon impacted industrial soil. The large scale project was carried out on a sandy loam, petroleum impacted soil [1613 mg total petroleum hydrocarbons (TPHs) kg(-1) soil]. The contaminated soil was amended with chemical fertilizers, inoculated with TPH degrading bacterial consortia and then used to construct passive biopiles. Finally, a phyto-cap of perennial rye grass (Lolium perenne) and white clover (Trifolium repens) was sown on the soil surface to complete the Ecopile. Monitoring of important physico-chemical parameters was carried out at regular intervals throughout the trial. Two years after construction the TPH levels in the petroleum impacted Ecopiles were below detectable limits in all but one subsample (152 mg TPH kg(-1) soil). The Ecopile system is a multi-factorial bioremediation process involving bio-stimulation, bio-augmentation and phytoremediation. One of the key advantages to this system is the reduced costs of the remediation process, as once constructed, there is little additional cost in terms of labor and maintenance (although the longer process time may incur additional monitoring costs). The other major advantage is that many ecological functions are rapidly restored to the site and the process is esthetically pleasing. PMID:25601875

  1. Ecopiling: a combined phytoremediation and passive biopiling system for remediating hydrocarbon impacted soils at field scale

    PubMed Central

    Germaine, Kieran J.; Byrne, John; Liu, Xuemei; Keohane, Jer; Culhane, John; Lally, Richard D.; Kiwanuka, Samuel; Ryan, David; Dowling, David N.

    2015-01-01

    Biopiling is an ex situ bioremediation technology that has been extensively used for remediating a wide range of petrochemical contaminants in soils. Biopiling involves the assembling of contaminated soils into piles and stimulating the biodegrading activity of microbial populations by creating near optimum growth conditions. Phytoremediation is another very successful bioremediation technique and involves the use of plants and their associated microbiomes to degrade, sequester or bio-accumulate pollutants from contaminated soil and water. The objective of this study was to investigate the effectiveness of a combined phytoremediation/biopiling system, termed Ecopiling, to remediate hydrocarbon impacted industrial soil. The large scale project was carried out on a sandy loam, petroleum impacted soil [1613 mg total petroleum hydrocarbons (TPHs) kg-1 soil]. The contaminated soil was amended with chemical fertilizers, inoculated with TPH degrading bacterial consortia and then used to construct passive biopiles. Finally, a phyto-cap of perennial rye grass (Lolium perenne) and white clover (Trifolium repens) was sown on the soil surface to complete the Ecopile. Monitoring of important physico-chemical parameters was carried out at regular intervals throughout the trial. Two years after construction the TPH levels in the petroleum impacted Ecopiles were below detectable limits in all but one subsample (152 mg TPH kg-1 soil). The Ecopile system is a multi-factorial bioremediation process involving bio-stimulation, bio-augmentation and phytoremediation. One of the key advantages to this system is the reduced costs of the remediation process, as once constructed, there is little additional cost in terms of labor and maintenance (although the longer process time may incur additional monitoring costs). The other major advantage is that many ecological functions are rapidly restored to the site and the process is esthetically pleasing. PMID:25601875

  2. Ecopiling: a combined phytoremediation and passive biopiling system for remediating hydrocarbon impacted soils at field scale.

    PubMed

    Germaine, Kieran J; Byrne, John; Liu, Xuemei; Keohane, Jer; Culhane, John; Lally, Richard D; Kiwanuka, Samuel; Ryan, David; Dowling, David N

    2014-01-01

    Biopiling is an ex situ bioremediation technology that has been extensively used for remediating a wide range of petrochemical contaminants in soils. Biopiling involves the assembling of contaminated soils into piles and stimulating the biodegrading activity of microbial populations by creating near optimum growth conditions. Phytoremediation is another very successful bioremediation technique and involves the use of plants and their associated microbiomes to degrade, sequester or bio-accumulate pollutants from contaminated soil and water. The objective of this study was to investigate the effectiveness of a combined phytoremediation/biopiling system, termed Ecopiling, to remediate hydrocarbon impacted industrial soil. The large scale project was carried out on a sandy loam, petroleum impacted soil [1613 mg total petroleum hydrocarbons (TPHs) kg(-1) soil]. The contaminated soil was amended with chemical fertilizers, inoculated with TPH degrading bacterial consortia and then used to construct passive biopiles. Finally, a phyto-cap of perennial rye grass (Lolium perenne) and white clover (Trifolium repens) was sown on the soil surface to complete the Ecopile. Monitoring of important physico-chemical parameters was carried out at regular intervals throughout the trial. Two years after construction the TPH levels in the petroleum impacted Ecopiles were below detectable limits in all but one subsample (152 mg TPH kg(-1) soil). The Ecopile system is a multi-factorial bioremediation process involving bio-stimulation, bio-augmentation and phytoremediation. One of the key advantages to this system is the reduced costs of the remediation process, as once constructed, there is little additional cost in terms of labor and maintenance (although the longer process time may incur additional monitoring costs). The other major advantage is that many ecological functions are rapidly restored to the site and the process is esthetically pleasing.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  4. [Changes of soil biological characters beneath greenhouse cucumber under different cultivation systems].

    PubMed

    Zhang, Xue-Yan; Tian, Yong-Qiang; Liu, Jun; Gao, Li-Hong

    2009-04-01

    A 3-year pot experiment with 8-year continuously cropped greenhouse cucumber soil was conducted to study the effects of different cultivation systems on the soil quality, soil nematode quantity, and crop yields. The third year' s data were taken into analysis. Comparing with traditional cultivation system (two seasons planting cucumber with fallowing in summer) , planting leafy vegetable and garlic in summer increased the yields of the two crops and the soil microbial biomass carbon content, total microbial population, and sucrase activity, decreased the amounts of soil nematode and root-knot nematode, and maintained a relative high Shannon-Weaver index. Planting crown daisy, garlic, and spinach in summer increased soil sucrase activity by 8.9%, 89.5%, and 36.9%, and the planting of crown daisy and garlic also increased the Shannon-Weaver index by 7.7% and 9.4%, respectively. All the results suggested that catching crop and rotation had definite restoration effects on the soil quality under continuously cropping of cucumber, and the effects of planting crown daisy and garlic were more significant.

  5. Detection of Landmines by Neutron Backscattering: Effects of Soil Moisture on the Detection System

    SciTech Connect

    Baysoy, D. Y.; Subasi, M.

    2010-01-21

    Detection of buried land mines by using neutron backscattering technique (NBS) is a well established method. It depends on detecting a hydrogen anomaly in dry soil. Since a landmine and its plastic casing contain much more hydrogen atoms than the dry soil, this anomaly can be detected by observing a rise in the number of neutrons moderated to thermal or epithermal energy. But, the presence of moisture in the soil limits the effectiveness of the measurements. In this work, a landmine detection system using the NBS technique was designed. A series of Monte Carlo calculations was carried out to determine the limits of the system due to the moisture content of the soil. In the simulations, an isotropic fast neutron source ({sup 252}Cf, 100 mug) and a neutron detection system which consists of five {sup 3}He detectors were used in a practicable geometry. In order to see the effects of soil moisture on the efficiency of the detection system, soils with different water contents were tested.

  6. The role of irrigation in the soil-crop system

    NASA Astrophysics Data System (ADS)

    Széles, Adrienn; Ragán, Péter; Nagy, János

    2015-04-01

    Agricultural production is performed in 85.5% of the total area of Hungary. Yearly average precipitation is 550-600 mm. Due to global warming, flooding, inland inundation and drought are frequent within a year. Extreme weather circumstances pose new challenges for crop producers. The results of long-term field experiments provide guidance to how each production technological intervention affects crop production, average yield and yield security. Examinations were performed on mid-heavy calcareous chenozem soil in a multifactorial small plot long-term field experiment under natural precipitation supply and irrigated circumstances to analyse the effect of irrigation and N fertilisation on soil moisture and maize grain yield. Drought and optimal years were involved in the examination. Six fertiliser treatments were used (0, 30, 60, 90, 120, 150 kg N ha-1) each year. Irrigation was performed with a Valmont linear equipment. Changes in soil moisture balance were examined with TDR-based soil moisture probes in the 0-120 cm profile. Evaluation was performed with SPSS. The moisture profiles of the 1.2 m soil profile show contrasting tendencies in different crop years in both irrigation treatments. In drought years, the 0-0.15 m layer showed the lowest moisture values (8.3-9.6 v/v%), increasing towards deeper layers. The significant (p<0.05) moisture content difference of 11-12 v/v% measured at the 12-leaf-stage constantly decreased by the end of the growing season as soil moisture stock decreased. In wet years, the highest moisture content was observed in the 0.15-0.30 m layer (37-39v/v%), decreasing towards deeper layers (13-16 v/v%). At natural precipitation supply, yield linearly increased until 60 kg ha-1 N in both years, but no yield surplus was obtained above this dose. Our results show that increasing N doses do not always cause yield increase if the water needed for nutrient uptake is limited. In irrigated treatments, the highest statistically significant yield was

  7. Mobilization of chrysene from soil in a model digestive system.

    PubMed

    Minhas, Jaswinder K; Vasiluk, Luba; Pinto, Linda J; Gobas, Frank A P C; Moore, Margo M

    2006-07-01

    Accurate estimates for the oral bioavailability of hydrophobic contaminants bound to solid matrices are challenging to obtain because of sorption to organic matter. The purpose of this research was to measure the bioavailability of [14C]chrysene sorbed to soil using an in vitro model of gastrointestinal digestion and absorption to a surrogate intestinal membrane, ethylene vinyl acetate (EVA) thin film. The [14C]chrysene moved rapidly from soil into the aqueous compartment and reached steady state within 2 h. Equilibrium was reached in the EVA film within 32 h. Aging the spiked soil for 6 or 12 months had no effect on chrysene mobilization. This was supported by the finding that the data best fit a one-compartment model. Despite significant decreases in [14C]chrysene mobilization when water or nonneutralized gastrointestinal fluids were used in place of the complete medium, the equilibrium concentration of [14C]chrysene in EVA film remained the same in all conditions. Thus, the driving force for uptake was the fugacity gradient between the aqueous phase and the EVA film. Cultured human enterocytes (human colorectal carcinoma cell line [Caco-2 cells]) had a higher lipid-normalized fugacity capacity than EVA film, but the elimination rate constants were the same, suggesting that the rate was controlled by the resistance of the unstirred aqueous layer at the membrane-water interface.

  8. Soil surface roughness and porosity under different tillage systems

    NASA Astrophysics Data System (ADS)

    Rodriguez-Gonzalez, J.; Saa-Requejo, A.; Gómez, J. A.; Valencia, J. L.; Zarco, P.; Tarquis, A. M.

    2012-04-01

    Both soil porosity and surface elevation can be altered by tillage operation. Even though the surface porosity is an important parameter of a tilled field, however, no practical technique for rapid and non-contact measurement of surface porosity has been developed yet. On the contrary, the surface elevation of tilled soil can be quickly determined with a laser profiler. Working under the assumption that the surface elevation of a tilled field is a complicated superposition of the soil terrain profile at a larger-scale and the roughness at a fine-scale, this study included three aspects: (i) to establish an index (Roughness Index, RI) at a fine-scale to associate the surface roughness with porosity; (ii) to examine the correlation between surface porosity and the proposed RI by three types of tillage treatment in the field; and (iii) to check the scaling/multiscaling behavior among different grid sizes of calculating RI on predicting surface porosity. Consequently, the statistical results from each tilled plot show a strong correlation between the surface porosity and the defined RI in an early stage (ca. 2 days) after tillage. Acknowledgements Funding provided by CEIGRAM (Research Centre for the Management of Agricultural and Environmental Risks)and Spanish Ministerio de Ciencia e Innovación (MICINN) through project AGL2010-21501/AGR is greatly appreciated.

  9. A review of the distribution coefficients of trace elements in soils: influence of sorption system, element characteristics, and soil colloidal properties.

    PubMed

    Shaheen, Sabry M; Tsadilas, Christos D; Rinklebe, Jörg

    2013-12-01

    Knowledge about the behavior and reactions of separate soil components with trace elements (TEs) and their distribution coefficients (Kds) in soils is a key issue in assessing the mobility and retention of TEs. Thus, the fate of TEs and the toxic risk they pose depend crucially on their Kd in soil. This article reviews the Kd of TEs in soils as affected by the sorption system, element characteristics, and soil colloidal properties. The sorption mechanism, determining factors, favorable conditions, and competitive ions on the sorption and Kd of TEs are also discussed here. This review demonstrates that the Kd value of TEs does not only depend on inorganic and organic soil constituents, but also on the nature and characteristics of the elements involved as well as on their competition for sorption sites. The Kd value of TEs is mainly affected by individual or competitive sorption systems. Generally, the sorption in competitive systems is lower than in mono-metal sorption systems. More strongly sorbed elements, such as Pb and Cu, are less affected by competition than mobile elements, such as Cd, Ni, and Zn. The sorption preference exhibited by soils for elements over others may be due to: (i) the hydrolysis constant, (ii) the atomic weight, (iii) the ionic radius, and subsequently the hydrated radius, and (iv) its Misono softness value. Moreover, element concentrations in the test solution mainly affect the Kd values. Mostly, values of Kd decrease as the concentration of the included cation increases in the test solution. Additionally, the Kd of TEs is controlled by the sorption characteristics of soils, such as pH, clay minerals, soil organic matter, Fe and Mn oxides, and calcium carbonate. However, more research is required to verify the practical utilization of studying Kd of TEs in soils as a reliable indicator for assessing the remediation process of toxic metals in soils and waters.

  10. Crop systems and plant roots can modify the soil water holding capacity

    NASA Astrophysics Data System (ADS)

    Doussan, Claude; Cousin, Isabelle; Berard, Annette; Chabbi, Abad; Legendre, Laurent; Czarnes, Sonia; Toussaint, Bruce; Ruy, Stéphane

    2015-04-01

    At the interface between atmosphere and deep sub-soil, the root zone plays a major role in regulating the flow of water between major compartments: groundwater / surface / atmosphere (drainage, runoff, evapotranspiration). This role of soil as regulator/control of water fluxes, but also as a supporting medium to plant growth, is strongly dependent on the hydric properties of the soil. In turn, the plant roots growing in the soil can change its structure; both in the plow layer and in the deeper horizons and, therefore, could change the soil properties, particularly hydric properties. Such root-related alteration of soil properties can be linked to direct effect of roots such as soil perforation during growth, aggregation of soil particles or indirect effects such as the release of exudates by roots that could modify the properties of water or of soil particles. On an another hand, the rhizosphere, the zone around roots influenced by the activity of root and associated microorganisms, could have a high influence on hydric properties, particularly the water retention. To test if crops and plant roots rhizosphere may have a significant effect on water retention, we conducted various experiment from laboratory to field scales. In the lab, we tested different soil and species for rhizospheric effect on soil water retention. Variation in available water content (AWC) between bulk and rhizospheric soil varied from non-significant to a significant increase (to about 16% increase) depending on plant species and soil type. In the field, the alteration of water retention by root systems was tested in different pedological settings for a Maize crop inoculated or not with the bacteria Azospirillum spp., known to alter root structure, growth and morphology. Again, a range of variation in AWC was evidenced, with significant increase (~30%) in some soil types, but more linked to innoculated/non-innoculated plants rather than to a difference between rhizospheric and bulk soil

  11. Representing life in the Earth system with soil microbial functional traits in the MIMICS model

    NASA Astrophysics Data System (ADS)

    Wieder, W. R.; Grandy, A. S.; Kallenbach, C. M.; Taylor, P. G.; Bonan, G. B.

    2015-06-01

    Projecting biogeochemical responses to global environmental change requires multi-scaled perspectives that consider organismal diversity, ecosystem processes, and global fluxes. However, microbes, the drivers of soil organic matter decomposition and stabilization, remain notably absent from models used to project carbon (C) cycle-climate feedbacks. We used a microbial trait-based soil C model with two physiologically distinct microbial communities, and evaluate how this model represents soil C storage and response to perturbations. Drawing from the application of functional traits used to model other ecosystems, we incorporate copiotrophic and oligotrophic microbial functional groups in the MIcrobial-MIneral Carbon Stabilization (MIMICS) model; these functional groups are akin to "gleaner" vs. "opportunist" plankton in the ocean, or r- vs. K-strategists in plant and animal communities. Here we compare MIMICS to a conventional soil C model, DAYCENT (the daily time-step version of the CENTURY model), in cross-site comparisons of nitrogen (N) enrichment effects on soil C dynamics. MIMICS more accurately simulates C responses to N enrichment; moreover, it raises important hypotheses involving the roles of substrate availability, community-level enzyme induction, and microbial physiological responses in explaining various soil biogeochemical responses to N enrichment. In global-scale analyses, we show that MIMICS projects much slower rates of soil C accumulation than a conventional soil biogeochemistry in response to increasing C inputs with elevated carbon dioxide (CO2) - a finding that would reduce the size of the land C sink estimated by the Earth system. Our findings illustrate that tradeoffs between theory and utility can be overcome to develop soil biogeochemistry models that evaluate and advance our theoretical understanding of microbial dynamics and soil biogeochemical responses to environmental change.

  12. Soil organic matter quality in intensive maize-based forage systems

    NASA Astrophysics Data System (ADS)

    Zavattaro, L.; Sacco, D.; Bertora, C.; Monaco, S.; Grignani, C.

    2009-04-01

    An experiment designed and managed as a long-term platform and aimed at studying the dynamics of soil organic matter (SOM) in 38 forage systems based on maize was started in 1992 on a deep calcareous loam soil. The treatments are typical of intensive livestock farms in the Po plain, NW Italy. The experimental design is a plot-scale, set up in 3 randomized blocks. Various techniques were combined to evaluate the N use efficiency and mineralization rates of different fresh organic material added to the soil: cattle slurry, farmyard manure (c. 230 and 350 kg ha-1 of N), maize stalks, roots or grass ley residues. The techniques concerning soil organic matter turnover included C and N annual budgets based on SOM content, in-situ incubations (net mineralization in buried bags), lab incubations (soil respiration, potentially mineralizable N PMN, soil microbial biomass SMB). The environmental impact of C and N cycle on groundwater and air quality was assessed through monitoring the soil and soil solution mineral N content, and the CO2, N2O and CH4 in-situ emissions using the closed chamber technique. While the crop yield and N uptake did not respond to types and levels of manures, the SOM amount and quality were modified by fertilization: treatments which received repeated applications of the different fresh organic materials increased SOM content and soil total N, but also the N supplying capacity, soil respiration and SMB when compared with soil that received no N fertilizer or urea. More in detail, farmyard manure additions in combination with the incorporation of maize stalks was the practice that mostly increased the total SOM content (C and N) and showed the maximum C sequestration potential (46% of C added as manure was retained in the soil), but fertilization with liquid slurry also exerted a potential in augmenting the soil C and N (26% of added C was retained), and the fraction of easily-mineralizable organic N. The residual effect of manures applied repeatedly

  13. Nitrogen cycling and microbial communities within soil microenvironments in integrated organic farming systems in Switzerland

    NASA Astrophysics Data System (ADS)

    Loaiza, Viviana; Pereira, Engil; van der Heijden, Marcel; Wittwer, Raphael; Six, Johan

    2015-04-01

    Soil tilling is part of standard agricultural field preparation practices both in conventional and organic cropping systems. Although used mostly for weed control, it presents several drawbacks including increased soil erosion, soil structure disruption and high soil moisture loss. The use of fast-growing cover crops to overcome weed pressure, in combination with conservation tillage has been identified as a possible management strategy in organic systems, yet the mechanisms by which these practices affect nitrogen dynamics is mostly unknown. In this study we use an existing 4-year-old field experiment that combines the use of different tilling intensities and four different cover crop treatments and analyze overall N cycling using 15N stable isotope techniques, physical fractionation methods, and quantitative functional gene assays. Preliminary results suggest that reduced tillage may promote the formation of large macroaggregates in organic systems. Lower proportions of small macroaggregates and microaggregates went to the assembly of large macroaggregates when a cover crop was present. Macroaggregates constitute the majority of soil volume and consequently contribute the most to overall carbon and nitrogen soil content. There is a trend of higher carbon content across all soil fractions in the organic tillage treatments with mixed and brassica cover crop treatments, although the differences were not significant, added effects may be seen with time. Overall, treatment effects are more pronounced in the 0-6cm soil layer. Ongoing quantitative functional gene expression assays will shed light on the role of microorganisms and contribute to understanding nitrogen availability, stabilization and loss in integrated organic systems.

  14. A GPS Backpack System for Mapping Soil and Crop Parameters in Agricultural Fields

    NASA Astrophysics Data System (ADS)

    Stafford, J. V.; Lebars, J. M.

    Farmers are having to gather increasing amounts of data on their soils and crops. Precision agriculture metre-by-metre is based on a knowledge of the spatial variation of soil and crop parameters across a field. The data has to be spatially located and GPS is an effective way of doing this. A backpack data logging system with GPS position tagging is described which has been designed to aid a fanner in the manual collection of data.

  15. Quantifying uncertainties of a Soil-Foundation Structure-Interaction System under Seismic Excitation

    SciTech Connect

    Tong, C

    2008-04-07

    We applied a spectrum of uncertainty quantification (UQ) techniques to the study of a two-dimensional soil-foundation-structure-interaction (2DSFSI) system (obtained from Professor Conte at UCSD) subjected to earthquake excitation. In the process we varied 19 uncertain parameters describing material properties of the structure and the soil. We present in detail the results for the different stages of our UQ analyses.

  16. C and N content in density fractions of whole soil and soil size fraction under cacao agroforestry systems and natural forest in Bahia, Brazil.

    PubMed

    Rita, Joice Cleide O; Gama-Rodrigues, Emanuela Forestieri; Gama-Rodrigues, Antonio Carlos; Polidoro, Jose Carlos; Machado, Regina Cele R; Baligar, Virupax C

    2011-07-01

    Agroforestry systems (AFSs) have an important role in capturing above and below ground soil carbon and play a dominant role in mitigation of atmospheric CO(2). Attempts has been made here to identify soil organic matter fractions in the cacao-AFSs that have different susceptibility to microbial decomposition and further represent the basis of understanding soil C dynamics. The objective of this study was to characterize the organic matter density fractions and soil size fractions in soils of two types of cacao agroforestry systems and to compare with an adjacent natural forest in Bahia, Brazil. The land-use systems studied were: (1) a 30-year-old stand of natural forest with cacao (cacao cabruca), (2) a 30-year-old stand of cacao with Erythrina glauca as shade trees (cacao + erythrina), and (3) an adjacent natural forest without cacao. Soil samples were collected from 0-10 cm depth layer in reddish-yellow Oxisols. Soil samples was separated by wet sieving into five fraction-size classes (>2000 μm, 1000-2000 μm, 250-1000 μm, 53-250 μm, and <53 μm). C and N accumulated in to the light (free- and intra-aggregate density fractions) and heavy fractions of whole soil and soil size fraction were determined. Soil size fraction obtained in cacao AFS soils consisted mainly (65 %) of mega-aggregates (>2000 μm) mixed with macroaggregates (32-34%), and microaggregates (1-1.3%). Soil organic carbon (SOC) and total N content increased with increasing soil size fraction in all land-use systems. Organic C-to-total N ratio was higher in the macroaggregate than in the microaggregate. In general, in natural forest and cacao cabruca the contribution of C and N in the light and heavy fractions was similar. However, in cacao + erythrina the heavy fraction was the most common and contributed 67% of C and 63% of N. Finding of this study shows that the majority of C and N in all three systems studied are found in macroaggregates, particularly in the 250-1000 μm size

  17. C and N Content in Density Fractions of Whole Soil and Soil Size Fraction Under Cacao Agroforestry Systems and Natural Forest in Bahia, Brazil

    NASA Astrophysics Data System (ADS)

    Rita, Joice Cleide O.; Gama-Rodrigues, Emanuela Forestieri; Gama-Rodrigues, Antonio Carlos; Polidoro, Jose Carlos; Machado, Regina Cele R.; Baligar, Virupax C.

    2011-07-01

    Agroforestry systems (AFSs) have an important role in capturing above and below ground soil carbon and play a dominant role in mitigation of atmospheric CO2. Attempts has been made here to identify soil organic matter fractions in the cacao-AFSs that have different susceptibility to microbial decomposition and further represent the basis of understanding soil C dynamics. The objective of this study was to characterize the organic matter density fractions and soil size fractions in soils of two types of cacao agroforestry systems and to compare with an adjacent natural forest in Bahia, Brazil. The land-use systems studied were: (1) a 30-year-old stand of natural forest with cacao (cacao cabruca), (2) a 30-year-old stand of cacao with Erythrina glauca as shade trees (cacao + erythrina), and (3) an adjacent natural forest without cacao. Soil samples were collected from 0-10 cm depth layer in reddish-yellow Oxisols. Soil samples was separated by wet sieving into five fraction-size classes (>2000 μm, 1000-2000 μm, 250-1000 μm, 53-250 μm, and <53 μm). C and N accumulated in to the light (free- and intra-aggregate density fractions) and heavy fractions of whole soil and soil size fraction were determined. Soil size fraction obtained in cacao AFS soils consisted mainly (65 %) of mega-aggregates (>2000 μm) mixed with macroaggregates (32-34%), and microaggregates (1-1.3%). Soil organic carbon (SOC) and total N content increased with increasing soil size fraction in all land-use systems. Organic C-to-total N ratio was higher in the macroaggregate than in the microaggregate. In general, in natural forest and cacao cabruca the contribution of C and N in the light and heavy fractions was similar. However, in cacao + erythrina the heavy fraction was the most common and contributed 67% of C and 63% of N. Finding of this study shows that the majority of C and N in all three systems studied are found in macroaggregates, particularly in the 250-1000 μm size aggregate class

  18. Efficient mapping of agricultural soils using a novel electromagnetic measurement system

    NASA Astrophysics Data System (ADS)

    Trinks, Immo; Pregesbauer, Michael

    2016-04-01

    "Despite all our accomplishments, we owe our existence to a six-inch layer of topsoil and the fact that it rains." - Paul Harvey. Despite the fact, that a farmers most precious good is the soil that he or she cultivates, in most cases actually very little is known about the soils that are being farmed. Agricultural soils are under constant threat through erosion, depletion, pollution and other degrading processes, in particular when considering intensive industrial scale farming. The capability of soils to retain water and soil moisture is of vital importance for their agricultural potential. Detailed knowledge of the physical properties of soils, their types and texture, water content and the depth of the agricultural layer would be of great importance for resource-efficient tillage with sub-area dependent variable depth, and the targeted intelligent application of fertilizers or irrigation. Precision farming, which has seen increasing popularity in the USA as well as Australia, is still in its infancy in Europe. Traditional near-surface geophysical prospection systems for agricultural soil mapping have either been based on earth resistance measurements using electrode-disks that require soil contact, with inherent issues, or electromagnetic induction (EMI) measurements conducted with EMI devices mounted in non-metallic sledges towed several metres behind survey vehicles across the fields. Every farmer passes over the fields several times during each growing season, working the soil and treating the crops. Therefore a novel user-friendly measurement system, the "Topsoil Mapper" (TSM) has been developed, which enables the farmer to simultaneously acquire soil conductivity information and derived soil parameters while anyway passing over the fields using different agricultural implements. The measurement principle of the TSM is electromagnetic induction using a multi-coil array to acquire conductivity information along a vertical profile down to approximately 1.1 m

  19. Toward more realistic projections of soil carbon dynamics by Earth system models

    USGS Publications Warehouse

    Luo, Y.; Ahlström, Anders; Allison, Steven D.; Batjes, Niels H.; Brovkin, V.; Carvalhais, Nuno; Chappell, Adrian; Ciais, Philippe; Davidson, Eric A.; Finzi, Adien; Georgiou, Katerina; Guenet, Bertrand; Hararuk, Oleksandra; Harden, Jennifer; He, Yujie; Hopkins, Francesca; Jiang, L.; Koven, Charles; Jackson, Robert B.; Jones, Chris D.; Lara, M.; Liang, J.; McGuire, Anthony; Parton, William; Peng, Changhui; Randerson, J.; Salazar, Alejandro; Sierra, Carlos A.; Smith, Matthew J.; Tian, Hanqin; Todd-Brown, Katherine E. O; Torn, Margaret S.; van Groenigen, Kees Jan; Wang, Ying; West, Tristram O.; Wei, Yaxing; Wieder, William R.; Xia, Jianyang; Xu, Xia; Xu, Xiaofeng; Zhou, T.

    2016-01-01

    Soil carbon (C) is a critical component of Earth system models (ESMs), and its diverse representations are a major source of the large spread across models in the terrestrial C sink from the third to fifth assessment reports of the Intergovernmental Panel on Climate Change (IPCC). Improving soil C projections is of a high priority for Earth system modeling in the future IPCC and other assessments. To achieve this goal, we suggest that (1) model structures should reflect real-world processes, (2) parameters should be calibrated to match model outputs with observations, and (3) external forcing variables should accurately prescribe the environmental conditions that soils experience. First, most soil C cycle models simulate C input from litter production and C release through decomposition. The latter process has traditionally been represented by first-order decay functions, regulated primarily by temperature, moisture, litter quality, and soil texture. While this formulation well captures macroscopic soil organic C (SOC) dynamics, better understanding is needed of their underlying mechanisms as related to microbial processes, depth-dependent environmental controls, and other processes that strongly affect soil C dynamics. Second, incomplete use of observations in model parameterization is a major cause of bias in soil C projections from ESMs. Optimal parameter calibration with both pool- and flux-based data sets through data assimilation is among the highest priorities for near-term research to reduce biases among ESMs. Third, external variables are represented inconsistently among ESMs, leading to differences in modeled soil C dynamics. We recommend the implementation of traceability analyses to identify how external variables and model parameterizations influence SOC dynamics in different ESMs. Overall, projections of the terrestrial C sink can be substantially improved when reliable data sets are available to select the most representative model structure

  20. Stock, turnover and functions of carbon in heavily weathered soils under lowland rainforest transformation systems

    NASA Astrophysics Data System (ADS)

    Guillaume, Thomas; Kuzyakov, Yakov

    2013-04-01

    Tropical rainforest are experiencing worldwide a strong lost through deforestation and transformation into agricultural systems. Land use changes in such ecosystems leads to major modifications of soils properties and processes. One indication of it are the losses of organic carbon content (Corg); an important soil fertility parameter in heavily weathered soil. Between 1985 and 2007, Sumatra (Indonesia) has lost half of his remaining natural rainforest, which currently covers only 30% the island. The deforestation is still ongoing and the main drivers of deforestation are oil palm, rubber and timber industries. Our study aims to identify and quantify the impacts of lowland rainforest transformation systems (TS): oil palm, rubber and jungle rubber plantations on soil organic carbon (SOC) and nitrogen (SON) quality, turnover and stocks and so, on soil fertility and functions. We hypothesize that transformation of natural lowland rainforest changes not only C stock and budget throughout quantity and quality of C input, but also DOM production and water consumption by vegetation, leading to a relocation of C in the subsoil. This should be reflected in C and N content in soil profile horizons as well as their δ13C and δ15N isotopic signatures. We will evaluate also C stability through biological, thermal and chemical stability in bulk soil and aggregate fractions. The TS investigated, including lowland rainforest as reference sites, are located in Jambi Province (Sumatra). Soil has been described and sampled per horizon on 4 replicates of each TS in 2 different regions (32 sites) in Autumn 2012. As hypothesized, first results show strong effects of forest transformation on C and N content, as well as on isotopic signatures of soil. Those results will also be used further to select DOM sampling depths and adequate horizons to perform sorption and incubation experiments.

  1. Atrazine and Diuron partitioning within a soil-water-surfactant system

    NASA Astrophysics Data System (ADS)

    Wang, P.; Keller, A.

    2006-12-01

    The interaction between pesticide and soil and water is even more complex in the presence of surfactants. In this study, batch equilibrium was employed to study the sorption of surfactants and the partitioning behaviors of Atrazine and Diuron within a soil-water-surfactant system. Five soils and four surfactants (nonionic Triton- 100, cationic Benzalkonium Chloride (BC), anionic Linear Alkylbenzenesulfonate (LAS), and anionic Sodium Dodecyl Sulfate (SDS)) were used. All surfactant sorption isotherms exhibited an initial linear increase at low surfactant concentrations but reached an asymptotic value as the surfactant concentrations increased. Among the surfactants, BC had the highest sorption onto all soils, followed by Triton-100 and then by LAS and SDS, implying that the nature of the charge significantly influences surfactant sorption. Sorption of either Triton-100 or BC was highly correlated with soil Cation Exchange Capacity (CEC) while that of LAS and SDS was complicated by the presence of Ca2+ and Mg2+ in the aqueous phase and the CEC sites. Both LAS and SDS formed complexes with Ca2+ and Mg2+, resulting in a significant decrease in the detergency of the surfactants. At high surfactant concentrations and with micelles present in the aqueous phase, the micelles formed a more competitive partitioning site for the pesticides, resulting in less pesticide sorbed to the soil. At low Triton-100 and BC concentration, the sorption of the surfactants first resulted in less Atrazine sorption but more Diuron sorption, implying competition between the surfactants and Atrazine, which serves as an indirect evidence that there is a different sorption mechanism for Atrazine. Atrazine is a weak base and it protonates and becomes positively charged near particle surfaces where the pH is much lower than in the bulk solution. The protonated Atrazine may then be held on the CEC sites via electrostatic attraction. Triton-100, LAS and SDS sorbed on the soil showed similar

  2. Comparative assessment of water infiltration of soils under different tillage systems in eastern Botswana

    NASA Astrophysics Data System (ADS)

    Moroke, T. S.; Dikinya, O.; Patrick, C.

    Water infiltration is an important component of water balance for improving crop production potential in dryland soil tillage systems in Botswana, particularly in the eastern region. Hardsetting soils common in arable lands of Botswana, often require some kind of tillage such as mouldboard ploughing, chiselling and ripping to improve waterharvesting and crop growth conditions. The objective of this study was to compare ponded cumulative infiltration, steady state infiltration rate and sorptivity of soils cultivated using deep ripping, single and double mouldboard ploughing. This study was conducted on Chromic Luvisols (sandy loam), Haplic Luvisols (sandy clay loam), Ferric Luvisols (clay loam), and Ferric Arenosols (sand). Infiltration was measured using double ring infiltrometer method for 4 h. Although infiltration was smaller on traffic line of deep ripping system at all sites, it was only significantly ( P < 0.05) different on Ferric Luvisols and Ferric Arenosols. Compared with conventional ploughing, steady state infiltration was greater but not significantly ( P > 0.05) different under deep ripped. Cumulative and steady state infiltration rate was greater under sandy than loamy soils, smaller under double ploughing compared with single ploughed and deep ripped soils. Sorptivity was not significantly ( P > 0.05) different among tillage systems but was greater under sandy than sandy loam soils. Information on tillage and infiltration can improve implementation of waterharvesting technologies and crop production in Botswana.

  3. Road Maintenance Experience Using Polyurethane (PU) Foam Injection System and Geocrete Soil Stabilization as Ground Rehabilitation

    NASA Astrophysics Data System (ADS)

    Fakhar, A. M. M.; Asmaniza, A.

    2016-07-01

    There are many types of ground rehabilation and improvement that can be consider and implement in engineering construction works for soil improvement in order to prevent road profile deformation in later stage. However, when comes to road maintenance especially on operated expressways, not all method can be apply directly as it must comply to opreation's working window and lane closure basis. Key factors that considering ideal proposal for ground rehabilitation are time, cost, quality and most importantly practicality. It should provide long lifespan structure in order to reduce continuous cycle of maintenance. Thus, this paper will present two approaches for ground rehabilitation, namely Polyurethane (PU) Foam Injection System and Geocrete Soil Stabilization. The first approach is an injection system which consists two-parts chemical grout of Isocynate and Polyol when mixed together within soil structure through injection will polymerized with volume expansion. The strong expansion of grouting causes significant compression and compacting of the surrounding soil and subsequently improve ground properties and uplift sunken structure. The later is a cold in-place recyclying whereby mixture process that combines in-situ soil materials, cement, white powder (alkaline) additive and water to produce hard yet flexible and durable ground layer that act as solid foundation with improved bearing capacity. The improvement of the mechanical behaviour of soil through these two systems is investigated by an extensive testing programme which includes in-situ and laboratory test in determining properties such as strength, stiffness, compressibility, bearing capacity, differential settlement and etc.

  4. Microbiological and faunal soil attributes of coffee cultivation under different management systems in Brazil.

    PubMed

    Lammel, D R; Azevedo, L C B; Paula, A M; Armas, R D; Baretta, D; Cardoso, E J B N

    2015-11-01

    Brazil is the biggest coffee producer in the world and different plantation management systems have been applied to improve sustainability and soil quality. Little is known about the environmental effects of these different management systems, therefore, the goal of this study was to use soil biological parameters as indicators of changes. Soils from plantations in Southeastern Brazil with conventional (CC), organic (OC) and integrated management systems containing intercropping of Brachiaria decumbens (IB) or Arachis pintoi (IA) were sampled. Total organic carbon (TOC), microbial biomass carbon (MBC) and nitrogen (MBN), microbial activity (C-CO2), metabolic quotient (qCO2), the enzymes dehydrogenase, urease, acid phosphatase and arylsulphatase, arbuscular mycorrhizal fungi (AMF) colonization and number of spores and soil fauna were evaluated. The greatest difference between the management systems was seen in soil organic matter content. The largest quantity of TOC was found in the OC, and the smallest was found in IA. TOC content influenced soil biological parameters. The use of all combined attributes was necessary to distinguish the four systems. Each management presented distinct faunal structure, and the data obtained with the trap method was more reliable than the TSBF (Tropical Soils) method. A canonic correlation analysis showed that Isopoda was correlated with TOC and the most abundant order with OC. Isoptera was the most abundant faunal order in IA and correlated with MBC. Overall, OC had higher values for most of the biological measurements and higher populations of Oligochaeta and Isopoda, corroborating with the concept that the OC is a more sustainable system. PMID:26628223

  5. Habitat Fragmentation can Modulate Drought Effects on the Plant-soil-microbial System in Mediterranean Holm Oak (Quercus ilex) Forests.

    PubMed

    Flores-Rentería, Dulce; Curiel Yuste, Jorge; Rincón, Ana; Brearley, Francis Q; García-Gil, Juan Carlos; Valladares, Fernando

    2015-05-01

    Ecological transformations derived from habitat fragmentation have led to increased threats to above-ground biodiversity. However, the impacts of forest fragmentation on soils and their microbial communities are not well understood. We examined the effects of contrasting fragment sizes on the structure and functioning of soil microbial communities from holm oak forest patches in two bioclimatically different regions of Spain. We used a microcosm approach to simulate the annual summer drought cycle and first autumn rainfall (rewetting), evaluating the functional response of a plant-soil-microbial system. Forest fragment size had a significant effect on physicochemical characteristics and microbial functioning of soils, although the diversity and structure of microbial communities were not affected. The response of our plant-soil-microbial systems to drought was strongly modulated by the bioclimatic conditions and the fragment size from where the soils were obtained. Decreasing fragment size modulated the effects of drought by improving local environmental conditions with higher water and nutrient availability. However, this modulation was stronger for plant-soil-microbial systems built with soils from the northern region (colder and wetter) than for those built with soils from the southern region (warmer and drier) suggesting that the responsiveness of the soil-plant-microbial system to habitat fragmentation was strongly dependent on both the physicochemical characteristics of soils and the historical adaptation of soil microbial communities to specific bioclimatic conditions. This interaction challenges our understanding of future global change scenarios in Mediterranean ecosystems involving drier conditions and increased frequency of forest fragmentation.

  6. The Effects of Different Tillage Systems on Soil Hydrology and Erosion in Southeastern Brazil

    NASA Astrophysics Data System (ADS)

    Bertolino, A. V. F. A.; Fernandes, N. F.; Souza, A. P.; Miranda, J. P.; Rocha, M. L.

    2009-04-01

    Conventional tillage usually imposes a variety of modifications on soil properties that can lead to important changes in the type and magnitude of the hydrological processes that take place at the upper portion of the soil profile. Plough pan formation, for example, is considered to be an important consequence of conventional tillage practices in southeastern Brazil, decreasing infiltration rates and contributing to soil erosion, especially in steep slopes. In order to characterize the changes in soil properties and soil hydrology due to the plough pan formation we carried out detailed investigations in two experimental plots in Paty do Alferes region, located in the hilly landscape of Serra do Mar in southeastern Brazil, close to Rio de Janeiro city. Farming activities are very important in this area, in particular the ones related to the tomato production. The local hilly topography with short and steep hillslopes, as well as an average annual rainfall of almost 2000 mm, favor surface runoff and the evolution of rill and gully erosion. The two runoff plots are 22m long by 4m wide and were installed side by side along a representative hillslope, both in terms of soil (Oxisol) and steepness. At the lower portion of each plot there is a collecting trough connected by a PVC pipe to a 500 and 1000 liters sediment storage boxes. Soil tillage treatments used in the two plots were: Conventional Tillage (CT), with one plowing using disc-type plow (about 18 cm depth) and one downhill tractor leveling, in addition to burning residues from previous planting; and Minimum Tillage (MT), which did not allow burning residues from previous planting and preserved a vegetative cover between plantation lines. Runoff and soil erosion measurements were carried out in both plots immediately after each rainfall event. In order to characterize soil water movements under the two tillage systems (CT and MT), 06 nests of tensiometers and 04 nests of Watermark sensors were installed in each

  7. 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

  8. Experimental system to displace radioisotopes from upper to deeper soil layers: chemical research

    PubMed Central

    Cazzola, Pietro; Cena, Agostino; Ghignone, Stefano; Abete, Maria C; Andruetto, Sergio

    2004-01-01

    Background Radioisotopes are introduced into the environment following nuclear power plant accidents or nuclear weapons tests. The immobility of these radioactive elements in uppermost soil layers represents a problem for human health, since they can easily be incorporated in the food chain. Preventing their assimilation by plants may be a first step towards the total recovery of contaminated areas. Methods The possibility of displacing radionuclides from the most superficial soil layers and their subsequent stabilisation at lower levels were investigated in laboratory trials. An experimental system reproducing the environmental conditions of contaminated areas was designed in plastic columns. A radiopolluted soil sample was treated with solutions containing ions normally used in fertilisation (NO3-, NH4+, PO4--- and K+). Results Contaminated soils treated with an acid solution of ions NO3-, PO4--- and K+, undergo a reduction of radioactivity up to 35%, after a series of washes which simulate one year's rainfall. The capacity of the deepest soil layers to immobilize the radionuclides percolated from the superficial layers was also confirmed. Conclusion The migration of radionuclides towards deeper soil layers, following chemical treatments, and their subsequent stabilization reduces bioavailability in the uppermost soil horizon, preventing at the same time their transfer into the water-bearing stratum. PMID:15132749

  9. Predicting hydrocarbon removal from thermally enhanced soil vapor extraction systems. 1. Laboratory studies.

    PubMed

    Poppendieck, D G; Loehr, R C; Webster, M T

    1999-10-01

    Conventional soil vapor extraction (SVE) systems have a limited effectiveness at removing semi-volatile chemicals from soil. Raising chemical vapor pressures by heating soil in-situ can decrease remediation time and help remove semi-volatile chemicals that otherwise would not be removed by conventional SVE. The increased compound removal rate that results from use of thermally enhanced SVE was investigated in laboratory studies. Increased soil temperatures (50-150 degrees C) increased both the rate of removal of the compounds studied and the range of compounds that were removed in column studies. The column studies indicated that if soil temperatures are raised enough to elevate the vapor pressure of a compound above 70 Pa, SVE will remove most of the compound from the soil. Thermally enhanced column study hydrocarbon removal rate constants were shown to have a definable relationship with vapor pressure. The relative removal rate constants also demonstrated an Arrhenius relationship with temperature. Laboratory studies can be used to develop these relationships and the results can be extrapolated within certain temperature ranges and compound types for a given soil.

  10. Geophysical Monitoring of Hydrocarbon-Contaminated Soils Remediated with a Bioelectrochemical System.

    PubMed

    Mao, Deqiang; Lu, Lu; Revil, André; Zuo, Yi; Hinton, John; Ren, Zhiyong Jason

    2016-08-01

    Efficient noninvasive techniques are desired for monitoring the remediation process of contaminated soils. We applied the direct current resistivity technique to image conductivity changes in sandbox experiments where two sandy and clayey soils were initially contaminated with diesel hydrocarbon. The experiments were conducted over a 230 day period. The removal of hydrocarbon was enhanced by a bioelectrochemical system (BES) and the electrical potentials of the BES reactors were also monitored during the course of the experiment. We found that the variation in electrical conductivity shown in the tomograms correlate well with diesel removal from the sandy soil, but this is not the case with the clayey soil. The clayey soil is characterized by a larger specific surface area and therefore a larger surface conductivity. In sandy soil, the removal of the diesel and products from degradation leads to an increase in electrical conductivity during the first 69 days. This is expected since diesel is electrically insulating. For both soils, the activity of BES reactors is moderately imaged by the inverted conductivity tomogram of the reactor. An increase in current production by electrochemically active bacteria activity corresponds to an increase in conductivity of the reactor.

  11. Soil Fungal Resources in Annual Cropping Systems and Their Potential for Management

    PubMed Central

    Esmaeili Taheri, Ahmad; Bainard, Luke D.; Yang, Chao; Navarro-Borrell, Adriana; Hamel, Chantal

    2014-01-01

    Soil fungi are a critical component of agroecosystems and provide ecological services that impact the production of food and bioproducts. Effective management of fungal resources is essential to optimize the productivity and sustainability of agricultural ecosystems. In this review, we (i) highlight the functional groups of fungi that play key roles in agricultural ecosystems, (ii) examine the influence of agronomic practices on these fungi, and (iii) propose ways to improve the management and contribution of soil fungi to annual cropping systems. Many of these key soil fungal organisms (i.e., arbuscular mycorrhizal fungi and fungal root endophytes) interact directly with plants and are determinants of the efficiency of agroecosystems. In turn, plants largely control rhizosphere fungi through the production of carbon and energy rich compounds and of bioactive phytochemicals, making them a powerful tool for the management of soil fungal diversity in agriculture. The use of crop rotations and selection of optimal plant genotypes can be used to improve soil biodiversity and promote beneficial soil fungi. In addition, other agronomic practices (e.g., no-till, microbial inoculants, and biochemical amendments) can be used to enhance the effect of beneficial fungi and increase the health and productivity of cultivated soils. PMID:25247177

  12. Geophysical Monitoring of Hydrocarbon-Contaminated Soils Remediated with a Bioelectrochemical System.

    PubMed

    Mao, Deqiang; Lu, Lu; Revil, André; Zuo, Yi; Hinton, John; Ren, Zhiyong Jason

    2016-08-01

    Efficient noninvasive techniques are desired for monitoring the remediation process of contaminated soils. We applied the direct current resistivity technique to image conductivity changes in sandbox experiments where two sandy and clayey soils were initially contaminated with diesel hydrocarbon. The experiments were conducted over a 230 day period. The removal of hydrocarbon was enhanced by a bioelectrochemical system (BES) and the electrical potentials of the BES reactors were also monitored during the course of the experiment. We found that the variation in electrical conductivity shown in the tomograms correlate well with diesel removal from the sandy soil, but this is not the case with the clayey soil. The clayey soil is characterized by a larger specific surface area and therefore a larger surface conductivity. In sandy soil, the removal of the diesel and products from degradation leads to an increase in electrical conductivity during the first 69 days. This is expected since diesel is electrically insulating. For both soils, the activity of BES reactors is moderately imaged by the inverted conductivity tomogram of the reactor. An increase in current production by electrochemically active bacteria activity corresponds to an increase in conductivity of the reactor. PMID:27386889

  13. Potential Soil Moisture Products from the Aquarius Radiometer and Scatterometer Using an Observing System Simulation Experiment

    SciTech Connect

    Luo, Yan; Houser, Paul; Anantharaj, Valentine G; Fan, Xingang; De Lannoy, Gabrielle; Zhan, Xiwu

    2013-01-01

    Using an observing system simulation experiment (OSSE), we investigate the potential soil moisture retrieval capability of the National Aeronautics and Space Administration (NASA) Aquarius radiometer (L-band 1.413 GHz) and scatterometer (L-band, 1.260 GHz). We estimate potential errors in soil moisture retrievals and identify the sources that could cause those errors. The OSSE system includes (i) a land surface model in the NASA Land Information System, (ii) a radiative transfer and backscatter model, (iii) a realistic orbital sampling model, and (iv) an inverse soil moisture retrieval model. We execute the OSSE over a 1000 2200 km2 region in the central United States, including the Red and Arkansas river basins. Spatial distributions of soil moisture retrieved from the radiometer and scatterometer are close to the synthetic truth. High root mean square errors (RMSEs) of radiometer retrievals are found over the heavily vegetated regions, while large RMSEs of scatterometer retrievals are scattered over the entire domain. The temporal variations of soil moisture are realistically captured over a sparely vegetated region with correlations 0.98 and 0.63, and RMSEs 1.28% and 8.23% vol/vol for radiometer and scatterometer, respectively. Over the densely vegetated region, soil moisture exhibits larger temporal variation than the truth, leading to correlation 0.70 and 0.67, respectively, and RMSEs 9.49% and 6.09% vol/vol respectively. The domain-averaged correlations and RMSEs suggest that radiometer is more accurate than scatterometer in retrieving soil moisture. The analysis also demonstrates that the accuracy of the retrieved soil moisture is affected by vegetation coverage and spatial aggregation.

  14. Potential soil moisture products from the Aquarius radiometer and scatterometer using an observing system simulation experiment

    NASA Astrophysics Data System (ADS)

    Luo, Y.; Feng, X.; Houser, P.; Anantharaj, V.; Fan, X.; De Lannoy, G.; Zhan, X.; Dabbiru, L.

    2012-07-01

    Using an Observing System Simulation Experiment (OSSE), we investigate the potential soil moisture retrieval capability of the National Aeronautics and Space Administration (NASA) Aquarius radiometer (L-band 1.413 GHz) and scatterometer (L-band, 1.260 GHz). We estimate potential errors in soil moisture retrievals and identify the sources that could cause those errors. The OSSE system includes: (i) a land surface model in the NASA Land Information System, (ii) a radiative transfer and backscatter model, (iii) a realistic orbital sampling model and (iv) an inverse soil moisture retrieval model. We execute the OSSE over a 1000 × 2200 km2 region in the central US, including the Red and Arkansas river basins. Spatial distributions of soil moisture retrieved from the radiometer and scatterometer are close to the synthetic truth. High root mean square errors (RMSEs) of radiometer retrievals are found over the heavily vegetated regions, while large RMSE of scatterometer retrievals are scattered over the entire domain. The temporal variations of soil moisture are realistically captured over a sparely vegetated region with correlations 0.98 and 0.63, and RMSEs 1.28% and 8.23% vol vol-1 for radiometer and scatterometer, respectively. Over the densely vegetated region, soil moisture exhibits larger temporal variation than the truth, leading to correlation 0.70 and 0.67 respectively, and RMSEs 9.49% and 6.09% vol vol-1 respectively. The domain averaged correlations and RMSEs suggest that radiometer is more accurate than scatterometer in retrieving soil moisture. The analysis also demonstrates that the accuracy of the retrieved soil moisture is affected by vegetation coverage and spatial aggregation.

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

    PubMed

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

    2012-04-01

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

  16. Nitrogen Effects on Organic Dynamics and Soil Communities in Forest and Agricultural Systems

    NASA Astrophysics Data System (ADS)

    Grandy, S.; Neff, J.; Sinsabaugh, B.; Wickings, K.

    2008-12-01

    Human activities have doubled the global flux of biologically available N to terrestrial ecosystems but the effects of N on soil organic matter dynamics and soil communities remain difficult to predict. We examined soil organic matter chemistry and enzyme kinetics in three soil fractions (>250, 63-250, and <63 μm) following six years of simulated atmospheric N deposition in two forest ecosystems with contrasting litter biochemistry (sugar maple/basswood and black oak/white oak). Ambient and simulated atmospheric N deposition (80 kg nitrate-N/ha/y) were studied in three replicate stands in each ecosystem type. Using pyrolysis-gas chromatography/mass spectroscopy, we found striking, ecosystem-specific effects of N deposition on carbohydrate abundance. Furfural, the dominant pyrolysis product of polysaccharides, was significantly decreased by simulated N deposition in the sugar maple/basswood system (15.87 versus 4.99%) but increased by N in the black oak/white oak system (8.83 versus 24.01%). There were ca. 3-fold increases in the ratio of total lignin derivatives to total polysaccharides in the >250 μm fraction of the sugar maple/basswood system but there were no changes in other size classes or in the black oak/white oak system. We also measured significant increases in the ratio of lignin derivatives to N-bearing compounds in the 63-250 and >250 μm fractions in both ecosystems but not in the <63 μm fraction. We compare these results to a study looking at changes in enzyme activities and soil communities along a N fertilizer gradient in a corn-based cropping system. Our results demonstrate that changes in soil organic matter chemistry resulting from atmospheric N deposition or fertilization are directly linked to variation in enzyme responses to increased N availability across ecosystems and soil size fractions.

  17. Long-term effect of rice-based farming systems on soil health.

    PubMed

    Bihari, Priyanka; Nayak, A K; Gautam, Priyanka; Lal, B; Shahid, M; Raja, R; Tripathi, R; Bhattacharyya, P; Panda, B B; Mohanty, S; Rao, K S

    2015-05-01

    Integrated rice-fish culture, an age-old farming system, is a technology which could produce rice and fish sustainably at a time by optimizing scarce resource use through complementary use of land and water. An understanding of microbial processes is important for the management of farming systems as soil microbes are the living part of soil organic matter and play critical roles in soil C and N cycling and ecosystem functioning of farming system. Rice-based integrated farming system model for small and marginal farmers was established in 2001 at Central Rice Research Institute, Cuttack, Odisha. The different enterprises of farming system were rice-fish, fish-fingerlings, fruits, vegetables, rice-fish refuge, and agroforestry. This study was conducted with the objective to assess the soil physicochemical properties, microbial population, carbon and nitrogen fractions, soil enzymatic activity, and productivity of different enterprises. The effect of enterprises induced significant changes in the chemical composition and organic matter which in turn influenced the activities of enzymes (urease, acid, and alkaline phosphatase) involved in the C, N, and P cycles. The different enterprises of long-term rice-based farming system caused significant variations in nutrient content of soil, which was higher in rice-fish refuge followed by rice-fish enterprise. Highest microbial populations and enzymatic properties were recorded in rice-fish refuge system because of waterlogging and reduced condition prolonged in this system leading to less decomposition of organic matter. The maximum alkaline phosphatase, urease, and FDA were observed in rice-fish enterprise. However, highest acid phosphatase and dehydrogenase activity were obtained in vegetable enterprise and fish-fingerlings enterprise, respectively.

  18. Long-term effect of rice-based farming systems on soil health.

    PubMed

    Bihari, Priyanka; Nayak, A K; Gautam, Priyanka; Lal, B; Shahid, M; Raja, R; Tripathi, R; Bhattacharyya, P; Panda, B B; Mohanty, S; Rao, K S

    2015-05-01

    Integrated rice-fish culture, an age-old farming system, is a technology which could produce rice and fish sustainably at a time by optimizing scarce resource use through complementary use of land and water. An understanding of microbial processes is important for the management of farming systems as soil microbes are the living part of soil organic matter and play critical roles in soil C and N cycling and ecosystem functioning of farming system. Rice-based integrated farming system model for small and marginal farmers was established in 2001 at Central Rice Research Institute, Cuttack, Odisha. The different enterprises of farming system were rice-fish, fish-fingerlings, fruits, vegetables, rice-fish refuge, and agroforestry. This study was conducted with the objective to assess the soil physicochemical properties, microbial population, carbon and nitrogen fractions, soil enzymatic activity, and productivity of different enterprises. The effect of enterprises induced significant changes in the chemical composition and organic matter which in turn influenced the activities of enzymes (urease, acid, and alkaline phosphatase) involved in the C, N, and P cycles. The different enterprises of long-term rice-based farming system caused significant variations in nutrient content of soil, which was higher in rice-fish refuge followed by rice-fish enterprise. Highest microbial populations and enzymatic properties were recorded in rice-fish refuge system because of waterlogging and reduced condition prolonged in this system leading to less decomposition of organic matter. The maximum alkaline phosphatase, urease, and FDA were observed in rice-fish enterprise. However, highest acid phosphatase and dehydrogenase activity were obtained in vegetable enterprise and fish-fingerlings enterprise, respectively. PMID:25913623

  19. Soil functioning in an agroextractivist system in the Eastern Amazon region under family farming management

    NASA Astrophysics Data System (ADS)

    Fernanda Simões da Silva, Laura; Nascimento Delgado Oliveira, Mariana; de Pierri Castilho, Selene Cristina; Cooper, Miguel

    2014-05-01

    Family farming has been identified as a major modifier of Amazonian vegetation cover. These small establishments have had problems with the availability of water resources, soil quality and, consequently, low crop production. Amazonian soils studies have generated data that make up a database about the changing soil conditions as a result of the land use modifications. The objective of this research is to understand the soil degradation processes that occur on two toposequences, under native forest and pasture, in a family farming establishment. The study area is located in the Piranheira Praialta Agroextrativist Settlement Project in the county of Nova Ipixuna, Pará, Brazil. Two toposequences were chosen, one under native forest and the other under pasture. Pits were opened in different landscape positions (upslope, midslope and downslope) for soil morphological, micromorphological and physical characterization. Samples were taken for soil particle distribution, bulk density, particle density, hydraulic conductivity and image analysis. The soils were classified according to World Reference Base (WRB-FAO, 2006) as Plinthic Acrisol Clayic, Haplic Cambisols Dystric Skeletic and Haplic Plinthosol Clayic Dystric. The results show that all the studied profiles presented higher contents of sand in the surface horizons and an increase in clay in the subsurface horizons. This indicates heterogeneity of the particle soil distribution in the soil profiles along the different landscape positions. Higher bulk density values are found in the surface horizons due to the sandy texture of these horizons. Under forest, soil bulk density varies from 1,260 to 1,580 Mg m3, and under pasture bulk densities were higher varying from 1,270 to 1,710 Mg m3. Soil particle density results obtained in both land use systems were very similar in all horizons varying from 2,580 to 2,630 Mg m3 under forest and from 2,580 to 2,670 under pasture. Image analysis results showed a significant decrease

  20. Enhanced chemical oxidation of aromatic hydrocarbons in soil systems.

    PubMed

    Kang, Namgoo; Hua, Inez

    2005-11-01

    Fenton's destruction of benzene, toluene, ethylbenzene, and xylene (BTEX) was investigated in soil slurry batch reactors. The purpose of the investigation was to quantify the enhancement of oxidation rates and efficiency by varying process conditions such as iron catalyst (Fe(II) or Fe(III); 2, 5, and 10mM), hydrogen peroxide (H2O2; 30, 150, 300 mM), and metal chelating agents (l-ascorbic acid, gallic acid, or N-(2-hydroxyethyl)iminodiacetic acid). Rapid contaminant mass destruction (97% after 3h) occurred in the presence of 300 mM H2O2 and 10 mM Fe(III). An enhanced removal rate (>90% removal after 15 min and 95% removal after 3h) was also observed by combining Fe(III), N-(2-hydroxyethyl)iminodiacetic acid and 300 mM H2O2. The observed BTEX mass removal rate constants (3.6-7.8 x 10(-4)s(-1)) were compared to the estimated rate constants (4.1-10.1 x 10(-3)s(-1)). The influence of non-specific oxidants loss (by reaction with iron hydroxides and soil organic matter) was also explored. PMID:16257314

  1. Inorganic fertilizer and poultry-litter manure amendments alter the soil microbial communities in agricultural systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of agricultural land management practices on soil prokaryotic diversity are not well described. We investigated three land usage systems (row cropped, ungrazed pasture, and cattle-grazed pasture) and two fertilizer systems (inorganic fertilizer or IF and poultry-litter or PL) and compare...

  2. Nutrients in soil water under three rotational cropping systems, Iowa, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    tSubsurface nutrient losses differ between annual and perennial crops; however, nutrient losses fromcropping systems that rotate annual and perennial crops are poorly documented. This study trackedNO3-N and P in soil water under three cropping systems suited for the U.S. Midwest, includingtwo-year (...

  3. On the role of patterns in understanding the functioning of soil-vegetation-atmosphere systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this paper, we review the role of patterns to improve our understanding of water, mass and energy exchange processes in soil-vegetation-atmosphere systems. We explore the main mechanisms that lead to the formation of patterns in these systems and discuss different approaches to characterizing and...

  4. Soil engineering in vivo: harnessing natural biogeochemical systems for sustainable, multi-functional engineering solutions.

    PubMed

    DeJong, Jason T; Soga, Kenichi; Banwart, Steven A; Whalley, W Richard; Ginn, Timothy R; Nelson, Douglas C; Mortensen, Brina M; Martinez, Brian C; Barkouki, Tammer

    2011-01-01

    Carbon sequestration, infrastructure rehabilitation, brownfields clean-up, hazardous waste disposal, water resources protection and global warming-these twenty-first century challenges can neither be solved by the high-energy consumptive practices that hallmark industry today, nor by minor tweaking or optimization of these processes. A more radical, holistic approach is required to develop the sustainable solutions society needs. Most of the above challenges occur within, are supported on, are enabled by or grown from soil. Soil, contrary to conventional civil engineering thought, is a living system host to multiple simultaneous processes. It is proposed herein that 'soil engineering in vivo', wherein the natural capacity of soil as a living ecosystem is used to provide multiple solutions simultaneously, may provide new, innovative, sustainable solutions to some of these great challenges of the twenty-first century. This requires a multi-disciplinary perspective that embraces the science of biology, chemistry and physics and applies this knowledge to provide multi-functional civil and environmental engineering designs for the soil environment. For example, can native soil bacterial species moderate the carbonate cycle in soils to simultaneously solidify liquefiable soil, immobilize reactive heavy metals and sequester carbon-effectively providing civil engineering functionality while clarifying the ground water and removing carbon from the atmosphere? Exploration of these ideas has begun in earnest in recent years. This paper explores the potential, challenges and opportunities of this new field, and highlights one biogeochemical function of soil that has shown promise and is developing rapidly as a new technology. The example is used to propose a generalized approach in which the potential of this new field can be fully realized.

  5. Soil engineering in vivo: harnessing natural biogeochemical systems for sustainable, multi-functional engineering solutions

    PubMed Central

    DeJong, Jason T.; Soga, Kenichi; Banwart, Steven A.; Whalley, W. Richard; Ginn, Timothy R.; Nelson, Douglas C.; Mortensen, Brina M.; Martinez, Brian C.; Barkouki, Tammer

    2011-01-01

    Carbon sequestration, infrastructure rehabilitation, brownfields clean-up, hazardous waste disposal, water resources protection and global warming—these twenty-first century challenges can neither be solved by the high-energy consumptive practices that hallmark industry today, nor by minor tweaking or optimization of these processes. A more radical, holistic approach is required to develop the sustainable solutions society needs. Most of the above challenges occur within, are supported on, are enabled by or grown from soil. Soil, contrary to conventional civil engineering thought, is a living system host to multiple simultaneous processes. It is proposed herein that ‘soil engineering in vivo’, wherein the natural capacity of soil as a living ecosystem is used to provide multiple solutions simultaneously, may provide new, innovative, sustainable solutions to some of these great challenges of the twenty-first century. This requires a multi-disciplinary perspective that embraces the science of biology, chemistry and physics and applies this knowledge to provide multi-functional civil and environmental engineering designs for the soil environment. For example, can native soil bacterial species moderate the carbonate cycle in soils to simultaneously solidify liquefiable soil, immobilize reactive heavy metals and sequester carbon—effectively providing civil engineering functionality while clarifying the ground water and removing carbon from the atmosphere? Exploration of these ideas has begun in earnest in recent years. This paper explores the potential, challenges and opportunities of this new field, and highlights one biogeochemical function of soil that has shown promise and is developing rapidly as a new technology. The example is used to propose a generalized approach in which the potential of this new field can be fully realized. PMID:20829246

  6. Utilizing surfactants to control the sorption, desorption, and biodegradation of phenanthrene in soil-water system.

    PubMed

    Jin, Haiwei; Zhou, Wenjun; Zhu, Lizhong

    2013-07-01

    An integrative technology including the surfactant enhanced sorption and subsequent desorption and biodegradation of phenanthrene in the soil-water system was introduced and tested. For slightly contaminated agricultural soils, cationic-nonionic mixed surfactant-enhanced sorption of organic contaminants onto soils could reduce their transfer to plants, therefore safe-guarding agricultural production. After planting, residual surfactants combined with added nonionic surfactant could also promote the desorption and biodegradation of residual phenanthrene, thus providing a cost-effective pollution remediation technology. Our results showed that the cationic-nonionic mixed surfactants dodecylpyridinium bromide (DDPB) and Triton X-100 (TX100) significantly enhanced soil retention of phenanthrene. The maximum sorption coefficient Kd of phenanthrene for contaminated soils treated by mixed surfactants was about 24.5 times that of soils without surfactant (Kd) and higher than the combined effects of DDPB and TX100 individually, which was about 16.7 and 1.5 times Kd, respectively. On the other hand, TX100 could effectively remove phenanthrene from contaminated soils treated by mixed surfactants, improving the bioavailability of organic pollutants. The desorption rates of phenanthrene from these treated soils were greater than 85% with TX100 concentration above 2000 mg/L and approached 100% with increasing TX100 concentration. The biodegradation rates of phenanthrene in the presence of surfactants reached over 95% in 30 days. The mixed surfactants promoted the biodegradation of phenanthrene to some extent in 10-22 days, and had no obvious impact on phenanthrene biodegradation at the end of the experiment. Results obtained from this study provide some insight for the production of safe agricultural products and a remediation scheme for soils slightly contaminated with organic pollutants.

  7. Artificial Root Exudate System (ARES): a field approach to simulate tree root exudation in soils

    NASA Astrophysics Data System (ADS)

    Lopez-Sangil, Luis; Estradera-Gumbau, Eduard; George, Charles; Sayer, Emma

    2016-04-01

    The exudation of labile solutes by fine roots represents an important strategy for plants to promote soil nutrient availability in terrestrial ecosystems. Compounds exuded by roots (mainly sugars, carboxylic and amino acids) provide energy to soil microbes, thus priming the mineralization of soil organic matter (SOM) and the consequent release of inorganic nutrients into the rhizosphere. Studies in several forest ecosystems suggest that tree root exudates represent 1 to 10% of the total photoassimilated C, with exudation rates increasing markedly under elevated CO2 scenarios. Despite their importance in ecosystem functioning, we know little about how tree root exudation affect soil carbon dynamics in situ. This is mainly because there has been no viable method to experimentally control inputs of root exudates at field scale. Here, I present a method to apply artificial root exudates below the soil surface in small field plots. The artificial root exudate system (ARES) consists of a water container with a mixture of labile carbon solutes (mimicking tree root exudate rates and composition), which feeds a system of drip-tips covering an area of 1 m2. The tips are evenly distributed every 20 cm and inserted 4-cm into the soil with minimal disturbance. The system is regulated by a mechanical timer, such that artificial root exudate solution can be applied at frequent, regular daily intervals. We tested ARES from April to September 2015 (growing season) within a leaf-litter manipulation experiment ongoing in temperate deciduous woodland in the UK. Soil respiration was measured monthly, and soil samples were taken at the end of the growing season for PLFA, enzymatic activity and nutrient analyses. First results show a very rapid mineralization of the root exudate compounds and, interestingly, long-term increases in SOM respiration, with negligible effects on soil moisture levels. Large positive priming effects (2.5-fold increase in soil respiration during the growing

  8. Observing soil water dynamics under two field conditions by a novel sensor system

    NASA Astrophysics Data System (ADS)

    Sheng, W.; Sun, Y.; Schulze Lammers, P.; Schumann, H.; Berg, A.; Shi, C.; Wang, C.

    2011-10-01

    SummarySufficiently available soil water is a basic requirement in agricultural production. Monitoring soil water dynamics (SWD) in the root zone is an optimal approach for managing a crop's growth. This study presents a novel sensor system that simultaneously measures volumetric soil water content (VSWC), apparent electrical conductivity (EC a) and soil temperature at two different soil depths (shallow: 16 cm; deep: 36 cm). For testing its feasibility in the field, two prototypes were installed, one in bare soil and the other in a sugar beet ( Beta vulgaris L.) field in the summer of 2010. Following a sequence of rainfall events randomly distributed over the experimental period, we observed distinct responses from the sensors at each monitored depth in both field conditions. In addition to the multi-parameter measurements, the novel sensor design includes a series of technical advantages such as solar-powered operation, wireless communication, and being relatively easy to install/remove. Thus, the developed wireless sensor system is promising for networked applications in precision farming.

  9. Satellite soil moisture for advancing our understanding of earth system processes and climate change

    NASA Astrophysics Data System (ADS)

    Dorigo, Wouter; de Jeu, Richard

    2016-06-01

    Soil moisture products obtained from active and passive microwave satellites have reached maturity during the last decade (De Jeu and Dorigo, 2016): On the one hand, research algorithms that were initially applied to sensors designed for other purposes, e.g., for measuring wind speed (e.g. the Advanced Scatterometer (ASCAT)), sea ice, or atmospheric parameters (e.g. the TRMM Microwave Imager (TMI) and the Advanced Microwave Scanning Radiometer - Earth Observing System AMSR-E), have developed into fully operational products. On the other hand, dedicated soil moisture satellite missions were designed and launched by ESA (the Soil Moisture Ocean Salinity (SMOS) mission) and NASA (the Soil Moisture Active Passive (SMAP) mission).

  10. ELBARA II, an L-Band Radiometer System for Soil Moisture Research

    PubMed Central

    Schwank, Mike; Wiesmann, Andreas; Werner, Charles; Mätzler, Christian; Weber, Daniel; Murk, Axel; Völksch, Ingo; Wegmüller, Urs

    2010-01-01

    L-band (1–2 GHz) microwave radiometry is a remote sensing technique that can be used to monitor soil moisture, and is deployed in the Soil Moisture and Ocean Salinity (SMOS) Mission of the European Space Agency (ESA). Performing ground-based radiometer campaigns before launch, during the commissioning phase and during the operative SMOS mission is important for validating the satellite data and for the further improvement of the radiative transfer models used in the soil-moisture retrieval algorithms. To address these needs, three identical L-band radiometer systems were ordered by ESA. They rely on the proven architecture of the ETH L-Band radiometer for soil moisture research (ELBARA) with major improvements in the microwave electronics, the internal calibration sources, the data acquisition, the user interface, and the mechanics. The purpose of this paper is to describe the design of the instruments and the main characteristics that are relevant for the user. PMID:22315556

  11. Assessment of metal bioavailability in the vineyard soil-grapevine system using different extraction methods.

    PubMed

    Vázquez Vázquez, Francisco A; Pérez Cid, Benita; Río Segade, Susana

    2016-10-01

    This study was focused on the assessment of single and sequential extraction methods to predict the bioavailability of metals in the vineyard soil-grapevine system. The modified BCR sequential extraction method and two single-step extraction methods based on the use of EDTA and acetic acid were applied to differently amended vineyard soils. The variety effect was studied on the uptake of metals by leaves and grapes. Most of the elements studied (Ca, Mg, Cu, Fe, Mn, Zn and Pb) were weakly mobilized from vineyard soils, with the exception of Cu and Mn. The determination of total metal content in leaves and grapes showed a different accumulation pattern in the two parts of the vine. A significant relationship was observed, for all the elements studied except for Fe, between the content bioavailable in the soil and the accumulated in both leaves and grapes (R=0.602-0.775, p<0.01).

  12. Ecological optimality in water-limited natural soil-vegetation systems. II - Tests and applications

    NASA Technical Reports Server (NTRS)

    Eagleson, P. S.; Tellers, T. E.

    1982-01-01

    The long-term optimal climatic climax soil-vegetation system is defined for several climates according to previous hypotheses in terms of two free parameters, effective porosity and plant water use coefficient. The free parameters are chosen by matching the predicted and observed average annual water yield. The resulting climax soil and vegetation properties are tested by comparison with independent observations of canopy density and average annual surface runoff. The climax properties are shown also to satisfy a previous hypothesis for short-term optimization of canopy density and water use coefficient. Using these hypotheses, a relationship between average evapotranspiration and optimum vegetation canopy density is derived and is compared with additional field observations. An algorithm is suggested by which the climax soil and vegetation properties can be calculated given only the climate parameters and the soil effective porosity. Sensitivity of the climax properties to the effective porosity is explored.

  13. Distribution of 152Eu and 154Eu in the 'alluvial soil-rhizosphere-plant roots' system.

    PubMed

    Kropatcheva, Marya; Chuguevsky, Alexei; Melgunov, Mikhail

    2012-04-01

    Accumulation of (152)Eu and (15)(4)Eu isotopes in bulk soil and rhizosphere soil in the near-field zone of influence of the Krasnoyarsk Mining and Chemical Combine was studied. An uneven distribution of specific activity of Eu isotopes was observed, with the gross specific activities of the isotopes in the bulk soil exceeding those of the rhizosphere. In the most contaminated locations the fine and the coarse granulometric fractions are enriched with the isotopes. A laboratory experiment indicated potential removal of soluble Eu isotopes by river flood waters may amount to 3% of the total Eu in both bulk and rhizosphere soils. The root system of plants growing in the contaminated territory accumulates (152)Eu and (154)Eu, although the isotopes were not discovered in aboveground parts of plants. Root-hairs were found to be the most contaminated.

  14. Microbial communities and soil fertility in flood irrigated orchards under different management systems in eastern spain

    NASA Astrophysics Data System (ADS)

    Morugán-Coronado, Alicia; García-Orenes, Fuensanta; Caravaca, Fuensanta; Roldán, Antonio

    2016-04-01

    Unsuitable land management such as the excessive use of herbicides can lead to a loss of soil fertility and a drastic reduction in the abundance of microbial populations and their functions related to nutrient cycling. Microbial communities are the most sensitive and rapid indicators of perturbations in agroecosystems. A field experiment was performed in an orange-trees orchard (Citrus sinensis) to assess the long-term effect of three different management systems on the soil microbial community biomass, structure and composition (phospholipid fatty acids (PLFAs) total, pattern, and abundance). The three agricultural systems assayed were established 30 years ago: herbicides (Glyphosate (N-(phosphonomethyl)glycine) with inorganic fertilizers (H), intensive ploughing and inorganic fertilizers (NPK 15%) (P) and organic farming (chipped pruned branches and weeds, manure from sheep and goats) (O). Nine soil samples were taken from each system. The results showed that the management practices including herbicides and intensive ploughing had similar results on soil microbial properties, while organic fertilization significantly increased microbial biomass, shifted the structure and composition of the soil microbial community, and stimulated microbial activity, when compared to inorganic fertilization systems; thus, enhancing the sustainability of this agroecosystem under semiarid conditions.

  15. Carbon dioxide emissions under different soil tillage systems in mechanically harvested sugarcane

    NASA Astrophysics Data System (ADS)

    Silva-Olaya, A. M.; Cerri, C. E. P.; La Scala, N., Jr.; Dias, C. T. S.; Cerri, C. C.

    2013-03-01

    Soil tillage and other methods of soil management may influence CO2 emissions because they accelerate the mineralization of organic carbon in the soil. This study aimed to quantify the CO2 emissions under conventional tillage (CT), minimum tillage (MT) and reduced tillage (RT) during the renovation of sugarcane fields in southern Brazil. The experiment was performed on an Oxisol in the sugarcane-planting area with mechanical harvesting. An undisturbed or no-till (NT) plot was left as a control treatment. The CO2 emissions results indicated a significant interaction (p < 0.001) between tillage method and time after tillage. By quantifying the accumulated emissions over the 44 days after soil tillage, we observed that tillage-induced emissions were higher after the CT system than the RT and MT systems, reaching 350.09 g m-2 of CO2 in CT, and 51.7 and 5.5 g m-2 of CO2 in RT and MT respectively. The amount of C lost in the form of CO2 due to soil tillage practices was significant and comparable to the estimated value of potential annual C accumulation resulting from changes in the harvesting system in Brazil from burning of plant residues to the adoption of green cane harvesting. The CO2 emissions in the CT system could respond to a loss of 80% of the potential soil C accumulated over one year as result of the adoption of mechanized sugarcane harvesting. Meanwhile, soil tillage during the renewal of the sugar plantation using RT and MT methods would result in low impact, with losses of 12% and 2% of the C that could potentially be accumulated during a one year period.

  16. Soil carbon fractions under maize-wheat system: effect of tillage and nutrient management.

    PubMed

    Sandeep, S; Manjaiah, K M; Pal, Sharmistha; Singh, A K

    2016-01-01

    Soil organic carbon plays a major role in sustaining agroecosystems and maintaining environmental quality as it acts as a major source and sink of atmospheric carbon. The present study aims to assess the impact of agricultural management practices on soil organic carbon pools in a maize-wheat cropping system of Indo-Gangetic Plains, India. Soil samples from a split plot design with two tillage systems (bed planting and conventional tillage) and six nutrient treatments (T1 = control, T2 = 120 kg urea-N ha(-1), T3 = T2 (25 % N substituted by FYM), T4 = T2 (25 % N substituted by sewage sludge), T5 = T2 + crop residue, T6 = 100 % organic source (50 % FYM + 25 % biofertilizer + 25 % crop residue) were used for determining the organic carbon pools. Results show that there was a significant improvement in Walkley and Black carbon in soil under integrated and organic nutrient management treatments. KMnO4-oxidizable carbon content of soil varied from 0.63 to 1.50 g kg(-1) in soils and was found to be a better indicator for monitoring the impact of agricultural management practices on quality of soil organic carbon than microbial biomass carbon. Tillage and its interaction were found to significantly influence only those soil organic carbon fractions closely associated with aggregate stability viz, labile polysaccharides and glomalin. The highest amount of C4-derived carbon was found to be in plots receiving recommended doses of N as urea (29 %) followed by control plots (25 %). The carbon management index ranged between 82 to 195 and was better in integrated nutrient sources than ones receiving recommended doses of nutrients through mineral fertilizers alone.

  17. Validation of the Global Land Data Assimilation System based on measurements of soil temperature profiles

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Li, Xiuping; Chen, Yingying; Yang, Kun; Chen, Deliang

    2016-04-01

    Soil temperature is a key parameter in the soil-vegetation-atmosphere system. It plays an important role in the land surface water and energy cycles, and has a major influence on vegetation growth and other hydrological aspects. We evaluated the accuracy of the soil temperature profiles from the Global Land Data Assimilation System (GLDAS) using nine observational networks across the world and aimed to find a reliable global soil temperature profile dataset for future hydrological and ecological studies. In general, the soil temperature profile data generated by the Noah model driven by the GLDAS forcing data (GLDAS_Noah10 and GLDAS_Noah10_v2) were found to have high skills in terms of daily, monthly, and mean seasonal variations, indicated by smaller bias and root-mean-square-error (RMSE) (both < 3 °C) and correlation coefficients larger than 0.90. Conversely, the Community Land Model (CLM) results (GLDAS_CLM10) generally showed larger bias and RMSE (both > 4°C). Further analysis showed that the overestimation by GLDAS_CLM10 was mainly caused by overestimation of the ground heat flux, determined by the thermal conductivity parameterization scheme, whereas the underestimation by GLDAS_Noah10 was due to underestimation of downward longwave radiation from the forcing data. Thus, more accurate forcing data should be required for the Noah model and an improved thermal parameterization scheme should be developed for the CLM. These approaches will improve the accuracy of simulated soil temperatures. To our knowledge, it is the first study to evaluate the GLDAS soil temperatures with comprehensive in situ observations across the world, and has a potential to facilitate an overall improvement of the GLDAS products (not only soil temperatures but also the related energy and water fluxes) as well as a refinement of the land surface parameterization used in GLDAS.

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

    USGS Publications Warehouse

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

    2008-01-01

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

  19. Soil carbon fractions under maize-wheat system: effect of tillage and nutrient management.

    PubMed

    Sandeep, S; Manjaiah, K M; Pal, Sharmistha; Singh, A K

    2016-01-01

    Soil organic carbon plays a major role in sustaining agroecosystems and maintaining environmental quality as it acts as a major source and sink of atmospheric carbon. The present study aims to assess the impact of agricultural management practices on soil organic carbon pools in a maize-wheat cropping system of Indo-Gangetic Plains, India. Soil samples from a split plot design with two tillage systems (bed planting and conventional tillage) and six nutrient treatments (T1 = control, T2 = 120 kg urea-N ha(-1), T3 = T2 (25 % N substituted by FYM), T4 = T2 (25 % N substituted by sewage sludge), T5 = T2 + crop residue, T6 = 100 % organic source (50 % FYM + 25 % biofertilizer + 25 % crop residue) were used for determining the organic carbon pools. Results show that there was a significant improvement in Walkley and Black carbon in soil under integrated and organic nutrient management treatments. KMnO4-oxidizable carbon content of soil varied from 0.63 to 1.50 g kg(-1) in soils and was found to be a better indicator for monitoring the impact of agricultural management practices on quality of soil organic carbon than microbial biomass carbon. Tillage and its interaction were found to significantly influence only those soil organic carbon fractions closely associated with aggregate stability viz, labile polysaccharides and glomalin. The highest amount of C4-derived carbon was found to be in plots receiving recommended doses of N as urea (29 %) followed by control plots (25 %). The carbon management index ranged between 82 to 195 and was better in integrated nutrient sources than ones receiving recommended doses of nutrients through mineral fertilizers alone. PMID:26638156

  20. Modelling global change impacts on soil carbon contents of agro-silvo-pastoral Mediterranean systems

    NASA Astrophysics Data System (ADS)

    Lozano-García, Beatriz; Muñoz-Rojas, Miriam; Parras-Alcántara, Luis

    2016-04-01

    To assess the impact of climate change on soil organic C (SOC) stocks in agro-silvo-pastoral environments, different models have been applied worldwide at local or regional scales, such as as RothC (Francaviglia et al., 2012) or CENTURY (Alvaro-Fuentes et al., 2012). However, some of these models may require a high number of input parameters or can underestimate the effect of soil depth. CarboSOIL (Muñoz-Rojas et al., 2013) is an empirical model based on regression techniques and developed to predict SOC contents at standard soil depths (0-25, 25-50 and 50-75 cm) under a range of climate and/or land use change scenarios. CarboSOIL has been successfully applied in different Mediterranean areas ,e.g. Southern Spain (Muñoz-Rojas et al., 2013; Abd-Elmabod et al., 2014), Northern Egypt (Muñoz-Rojas et al., 2014) and Italy (Muñoz-Rojas et al., 2015). In this study, CarboSOIL was applied in the Cardeña and Montoro mountain range Natural Park. This area covers 385 km2 and is located within Sierra Morena (Córdoba, South Spain) and has a semiarid Mediterranean climate. It is characterized by agro-silvo-pastoral systems. The Mediterranean evergreen oak woodland (MEOW-dehesa) is savanna-like open woodland ecosystem characterized by silvopastoral uses, being an ancient human modified Mediterranean landscape (Corral-Fernández et al., 2013; Lozano-García and Parras-Alcántara 2013). The most representative soils in the Cardeña and Montoro mountain range Natural Park are Cambisols, Regosols, Leptosols and Fluvisols. These soils are characterized by low fertility, poor physical conditions and marginal capacity for agricultural use, together with low organic matter (OM) content due to climate conditions (semiarid Mediterranean climate) and soil texture (sandy). The model was applied at different soil depths: 0-25, 25-50 and 50-75 cm (Parras-Alcántara et al., 2015) considering land use and climate changes scenarios based on available global climate models (IPPC, 2007). A

  1. Effect of cropping systems on adsorption of metals by soils: I. Single-metal adsorption

    SciTech Connect

    Basta, N.T.; Tabatabai, M.A. )

    1992-02-01

    The effect of long-term cropping systems on adsorption of metals was studied for soils obtained from two sites, Clarion-Webster Research Center (CWRC site) at Kanawha and Galva-Primghar Research Center (GPRC site) at Sutherland, under long-term rotation experiments in Iowa. Each experiment consisted of three cropping systems: continuous corn (CCCC), corn-soybean-corn-soybean (CSCS), and corn-oats-meadow-meadow (COMM), and treated with (+N) and without (0 N) ammoniacal fertilizer. In general, CSCS and COMM cropping systems did not significantly affect the metal adsorption maxima of soils obtained from both sites. Cadmium, Cu, and Pb adsorption were significantly correlated with pH and percentage base saturation for soils from both sites.

  2. Analytical modeling of structure-soil systems for lunar bases

    NASA Technical Reports Server (NTRS)

    Macari-Pasqualino, Jose Emir

    1989-01-01

    The study of the behavior of granular materials in a reduced gravity environment and under low effective stresses became a subject of great interest in the mid 1960's when NASA's Surveyor missions to the Moon began the first extraterrestrial investigation and it was found that Lunar soils exhibited properties quite unlike those on Earth. This subject gained interest during the years of the Apollo missions and more recently due to NASA's plans for future exploration and colonization of Moon and Mars. It has since been clear that a good understanding of the mechanical properties of granular materials under reduced gravity and at low effective stress levels is of paramount importance for the design and construction of surface and buried structures on these bodies. In order to achieve such an understanding it is desirable to develop a set of constitutive equations that describes the response of such materials as they are subjected to tractions and displacements. This presentation examines issues associated with conducting experiments on highly nonlinear granular materials under high and low effective stresses. The friction and dilatancy properties which affect the behavior of granular soils with low cohesion values are assessed. In order to simulate the highly nonlinear strength and stress-strain behavior of soils at low as well as high effective stresses, a versatile isotropic, pressure sensitive, third stress invariant dependent, cone-cap elasto-plastic constitutive model was proposed. The integration of the constitutive relations is performed via a fully implicit Backward Euler technique known as the Closest Point Projection Method. The model was implemented into a finite element code in order to study nonlinear boundary value problems associated with homogeneous as well as nonhomogeneous deformations at low as well as high effective stresses. The effect of gravity (self-weight) on the stress-strain-strength response of these materials is evaluated. The calibration

  3. Soil Warming Alters the Nitrogen Cycle: Ecosystem Implications and Feedbacks to the Climate System

    NASA Astrophysics Data System (ADS)

    Butler, S. M.; Melillo, J. M.; Johnson, J. E.; Mohan, J. E.; Steudler, P. A.; Bowles, F. P.

    2008-12-01

    Increases in soil temperatures associated with global warming have the potential to accelerate nitrogen turnover in soils, which could alter other biogeochemical processes and eventually affect the structure of these forests. Over the past five years we have been studying soil and plant responses to soil warming in large plots in a deciduous stand at Harvard Forest in central Massachusetts. We have heated the soil 5°C above ambient and measured nitrogen cycling parameters including in situ net nitrogen mineralization and nitrification, nitrogen leaching and nitrous oxide (N2O) fluxes. We have also measured various aspects of the carbon cycle including soil respiration and carbon accumulation in vegetation. Over the first five years of the study, we observed a mean annual increase in the net nitrogen mineralized in the warmed plot of 23.8 kg N ha-1. While nitrification rates were low throughout the five years in the control plot, they increased in the warmed plot to account for over 25% of the total net nitrogen mineralized in year five. The increase in nitrogen mineralization stimulated tree growth and carbon storage in woody tissue in the warmed plot. The increased carbon storage in the trees compensated for more than half of the carbon lost from the soils due to accelerated decay of soil organic matter and so reduced the magnitude of the positive feedback to the climate system due to soil warming. We hypothesize that the increase in nitrification we observed will eventually "open" the nitrogen cycle and make gaseous and solution losses more likely. To date, however, we have measured no major losses of nitrous oxide or solution losses of nitrate in response to soil warming. Trees with the capacity to use nitrate may have a competitive advantage in a warmer world. Nitrate-using plants have an inducible enzyme that transforms nitrate to ammonium, a key building block for producing essential amino acids and proteins. Studies by our research group and by others have

  4. Cover crops and crop residue management under no-till systems improve soils and environmental quality

    NASA Astrophysics Data System (ADS)

    Kumar, Sandeep; Wegner, Brianna; Vahyala, Ibrahim; Osborne, Shannon; Schumacher, Thomas; Lehman, Michael

    2015-04-01

    Crop residue harvest is a common practice in the Midwestern USA for the ethanol production. However, excessive removal of crop residues from the soil surface contributes to the degradation of important soil quality indicators such as soil organic carbon (SOC). Addition of a cover crop may help to mitigate these negative effects. The present study was set up to assess the impacts of corn (Zea mays L.) residue removal and cover crops on various soil quality indicators and surface greenhouse gas (GHG) fluxes. The study was being conducted on plots located at the North Central Agricultural Research Laboratory (NCARL) in Brookings, South Dakota, USA. Three plots of a corn and soybean (Glycine max (L.) Merr.) rotation under a no-till (NT) system are being monitored for soils and surface gas fluxes. Each plot has three residue removal (high residue removal, HRR; medium residue removal, MRR; and low residue removal, LRR) treatments and two cover crops (cover crops and no cover crops) treatments. Both corn and soybean are represented every year. Gas flux measurements were taken weekly using a closed static chamber method. Data show that residue removal significantly impacted soil quality indicators while more time was needed for an affect from cover crop treatments to be noticed. The LRR treatment resulted in higher SOC concentrations, increased aggregate stability, and increased microbial activity. The LRR treatment also increased soil organic matter (SOM) and particulate organic matter (POM) concentrations. Cover crops used in HRR (high corn residue removal) improved SOC (27 g kg-1) by 6% compared to that without cover crops (25.4 g kg-1). Cover crops significantly impacted POM concentration directly after the residue removal treatments were applied in 2012. CO2 fluxes were observed to increase as temperature increased, while N2O fluxes increased as soil moisture increased. CH4 fluxes were responsive to both increases in temperature and moisture. On average, soils under

  5. The validation of forensic DNA extraction systems to utilize soil contaminated biological evidence.

    PubMed

    Kasu, Mohaimin; Shires, Karen

    2015-07-01

    The production of full DNA profiles from biological evidence found in soil has a high failure rate due largely to the inhibitory substance humic acid (HA). Abundant in various natural soils, HA co-extracts with DNA during extraction and inhibits DNA profiling by binding to the molecular components of the genotyping assay. To successfully utilize traces of soil contaminated evidence, such as that found at many murder and rape crime scenes in South Africa, a reliable HA removal extraction system would often be selected based on previous validation studies. However, for many standard forensic DNA extraction systems, peer-reviewed publications detailing the efficacy on soil evidence is either lacking or is incomplete. Consequently, these sample types are often not collected or fail to yield suitable DNA material due to the use of unsuitable methodology. The aim of this study was to validate the common forensic DNA collection and extraction systems used in South Africa, namely DNA IQ, FTA elute and Nucleosave for processing blood and saliva contaminated with HA. A forensic appropriate volume of biological evidence was spiked with HA (0, 0.5, 1.5 and 2.5 mg/ml) and processed through each extraction protocol for the evaluation of HA removal using QPCR and STR-genotyping. The DNA IQ magnetic bead system effectively removed HA from highly contaminated blood and saliva, and generated consistently acceptable STR profiles from both artificially spiked samples and crude soil samples. This system is highly recommended for use on soil-contaminated evidence over the cellulose card-based systems currently being preferentially used for DNA sample collection.

  6. Using radium isotopes as tracers of transfers in the soil - water- -plant system

    NASA Astrophysics Data System (ADS)

    Rihs, S.; Pierret, M.-C.; Chabaux, F.

    2012-04-01

    Because soils form at the critical interface between the lithosphere and the atmosphere, characterization of the dynamics occurring through this compartment represents an important goal for several scientific fields and/or human activities. However, this issue remains a challenge because soils are complex systems, where a continuous evolution of minerals and organic soil constituents occurs in response to interactions with waters and vegetation. This study aims to investigate the relevance of short-lived nuclides of U- and Th-series to quantify the transfer times and scheme of radionuclides through a soil - water - plant ecosystem. Activities of (226Ra), (228Ra) as well as (228Th) were measured by TIMS and gamma-spectrometry in the major compartments of a forested soil section: solid soil fractions (exchangeable fraction, secondary phases and inherited primary minerals), waters (seepage soil waters and a spring further down the watershed) and vegetation (fine and coarse roots of beech trees, young and mature leaves). The matching of these nuclides half-live to bio-geochemical processes time-scale and the relatively good chemical analogy of radium with calcium make these isotopes especially suitable to investigate either time or mechanism of transfers within a soil-water-plant system. Indeed, the (228Ra/226Ra) isotopic ratios strongly differ in the range of samples, allowing quantifying the source and duration transfers. Analyses of the various solid soil fractions demonstrate a full redistribution of Ra isotopes between the inherited minerals and secondary soil phases. Moreover, the transfer of these isotopes to the seepage water or to the tree roots does not follow a simple and obvious scheme. The radium isotopic ratio in the trees roots does not match the soil exchangeable fraction, suggesting a mixed pool of radium for roots uptake. Decay of 228Ra within the various parts of the trees allows calculating a vegetation cycling duration of about 12 years for this

  7. [Modeling of Cs-137 vertical soil transfer by a tree root system].

    PubMed

    Bulgakov, A A; Konoplev, A V

    2002-01-01

    A model of 137Cs vertical soil transport by a tree root system is presented. As distinct from other models the radionuclide root uptake is described as a reversible process and depth distribution of roots is given as a function of time. The model was used for prediction of 137Cs release from a surface disposal site located in a territory with conditions similar to that in the Chernobyl NPP exclusion zone. Prediction indicates that during several decades 137Cs transport from the waste layer by the root system of pine can lead to significant contamination of the soil surface due to needles fallout and, probably, ionic leakage from roots. PMID:12449825

  8. Local soil fertility management on small-scale farming systems for sustainable agriculture

    NASA Astrophysics Data System (ADS)

    Namriah, Kilowasid, Laode Muhammad Harjoni

    2015-09-01

    The sustainability of small-scale farming systems on marginal lands is still being a topic of debate in scientific and institutional communities. To address this, a study was conducted to find a method of sustaining the productivity of marginal lands for food crop production. Agricultural practices (fallow and traditional cultivation) used by the local small-scale farmers in managing soil fertility to meet the natural biological processes above and below the ground were studied in Muna Island Southeast Sulawesi, Indonesia. Participatory approach was used to gather data and information on soil and land as well as to collect soil macrofauna. The results showed that the practices of local small-scale farmers are based on local soil and land suitability. Organic materials are the source of nutrient inputs to sustain the productivity of their lands by fallowing, burning natural vegetation, putting back the crop residues, doing minimum tillage and mix- and inter-crops. In conclusion, the sustainability of local small-scale farming systems will be established by knowing and understanding local soil and land classification systems and preferred crops being planted. Following the nature of fallow and monitoring soil macrofauna diversity and abundance, all preferred crops should be planted during rainy season with different time of harvest until the next rainy season. Therefore, soils are still covered with crops during dry season. It was suggested that planting time should be done in the rainy season. Doing more researches in other locations with different socio-cultural, economical, and ecological conditions is suggested to validate and refine the method.

  9. Mechanism for the primary transformation of acetaminophen in a soil/water system.

    PubMed

    Liang, Chuanzhou; Lan, Zhonghui; Zhang, Xu; Liu, Yingbao

    2016-07-01

    The transformation of acetaminophen (APAP) in a soil/water system was systematically investigated by a combination of kinetic studies and a quantitative analysis of the reaction intermediates. Biotransformation was the predominant pathway for the elimination of APAP, whereas hydrolysis or other chemical transformation, and adsorption processes made almost no contribution to the transformation under a dark incubation. Bacillus aryabhattai strain 1-Sj-5-2-5-M, Klebsiella pneumoniae strain S001, and Bacillus subtilis strain HJ5 were the main bacteria identified in the biotransformation of APAP. The soil-to-water ratio and soil preincubation were able to alter the transformation kinetic pattern. Light irradiation promoted the overall transformation kinetics through enhanced biotransformation and extra photosensitized chemical reactions. The transformation pathways were strongly dependent on the initial concentration of APAP. The main primary transformation products were APAP oligomers and p-aminophenol, with the initial addition of 26.5 and 530 μM APAP, respectively. APAP oligomers accounted for more than 95% of transformed APAP, indicating that almost no bound residues were generated through the transformation of APAP in the soil/water system. The potential environmental risks of APAP could increase following the transformation of APAP in the soil/water system because of the higher toxicity of the transformation intermediates. PMID:27107139

  10. The Agr communication system provides a benefit to the populations of Listeria monocytogenes in soil

    PubMed Central

    Vivant, Anne-Laure; Garmyn, Dominique; Gal, Laurent; Piveteau, Pascal

    2014-01-01

    In this study, we investigated whether the Agr communication system of the pathogenic bacterium Listeria monocytogenes was involved in adaptation and competitiveness in soil. Alteration of the ability to communicate, either by deletion of the gene coding the response regulator AgrA (response-negative mutant) or the signal pro-peptide AgrD (signal-negative mutant), did not affect population dynamics in soil that had been sterilized but survival was altered in biotic soil suggesting that the Agr system of L. monocytogenes was involved to face the complex soil biotic environment. This was confirmed by a set of co-incubation experiments. The fitness of the response-negative mutant was lower either in the presence or absence of the parental strain but the fitness of the signal-negative mutant depended on the strain with which it was co-incubated. The survival of the signal-negative mutant was higher when co-cultured with the parental strain than when co-cultured with the response-negative mutant. These results showed that the ability to respond to Agr communication provided a benefit to listerial cells to compete. These results might also indicate that in soil, the Agr system controls private goods rather than public goods. PMID:25414837

  11. The impact of cultivar diversity in bioenergy feedstock production systems on soil carbon sequestration rates

    NASA Astrophysics Data System (ADS)

    De Graaff, M.; Morris, G.; Jastrow, J. D.; SIX, J. W.

    2013-12-01

    Land-use change for bioenergy production can create greenhouse gas (GHG) emissions through disturbance of soil carbon (C) pools, but native species with extensive root systems may rapidly repay the GHG debt, particularly when grown in diverse mixtures, by enhancing soil C sequestration upon land-use change. Native bioenergy candidate species, switchgrass (Panicum virgatum L.) and big bluestem (Andropogon gerardii) show extensive within-species variation, and our preliminary data show that increased cultivar diversity can enhance yield. We aim to assess how shifting C3-dominated nonnative perennial grasslands to C4-dominated native perennial grasslands for use as bioenergy feedstock affects soil C stocks, and how within-species diversity in switchgrass and big bluestem affects soil C sequestration rates. Our experiment is conducted at the Fermilab National Environmental Research Park, and compares different approaches for perennial feedstock production ranging across a biodiversity gradient, where diversity is manipulated at both the species- and cultivar level, and nitrogen (N) is applied at two levels (0 and 67 kg/ha). Preliminary results indicate that switchgrass and big bluestem differentially affect soil C sequstration, and that increasing diversity may enhance soil C sequestration rates.

  12. Artificial soil formation and stabilization of material cycles in closed ecological systems for Mars habitats

    NASA Astrophysics Data System (ADS)

    Borchardt, Joshua D.

    Scientists are increasingly pressured to investigate novel ways in which to feed astronauts for the first mission to Mars in the 2030s. It is the aim of this thesis to conduct a preliminary investigation for soil formation of NASA JSC Mars-1A Regolith Simulant in an environmentally closed ecosystem to simulate plant growth within these initial habitats, and the prospect of soil formation from a Mars parent material for agricultural purposes. The rhizosphere and plant stress will be the main regions of research focus. It is hypothesized rhizosphere activity will determine the rate of stable soil formation adequate to support the agricultural needs of Mars's first human inhabitants. A Brassica rapa (Wisconsin FastPlant(TM)) was grown on several different substrates, and evaluated for plant stress, elemental analysis, soil fertility, and mineralogical analysis to identify the biogeochemical factors related to areas inside and outside of the rhizosphere, which affect soil formation. In addition, multiple plant generations were grown to investigate bioavailability of nutrients within the system, and lay down preliminary approaches for mathematical model development in order to predict & evaluate future conditions and applications under reduced resource availability situations. Overall, the story of early soil formation from a Mars regolith simulant is further defined to aid in the success of our first human adventurers to the red planet.

  13. Modelling soil carbon in agricultural systems: a way to widen the experimental space

    NASA Astrophysics Data System (ADS)

    O'Leary, Garry; Li Liu, De; Nuttall, James; Rajin Anwar, Muhuddin; Robertson, Fiona

    2015-07-01

    Mechanistic and explanatory simulation models provide robust and objective methods to extrapolate likely responses of crops and soils to climate change over different landscapes and time periods. Central to such simulation models are the supply of mineralised nutrients, in particular nitrogen, to crops through linked crop and nutrient sub-models that is achieved through modelling soil carbon dynamics. Attention to soil processes is therefore an essential part of building robust and sustainable production systems and understanding the potential impacts of climate change. To the farmer, focus must be on the productive capacity of the land and its rejuvenation to sustain production. In the broader context of reducing atmospheric CO2 concentration through soil C sequestration, understanding soil processes and the immediate environment likewise require attention to productivity issues. This is because without maintaining productivity a better understanding of soil organic carbon (SOC) processes is unlikely to lead to increased SOC sequestration in Australia's farming land. Some gaps in knowledge of how to manage SOC are being addressed in a national research effort, including the scant measured data against which models can be tested. Nevertheless, continuing to apply models to push the boundaries well beyond what can be achieved in practice widens the experimental space, allowing new ideas to be tested where physical experiments are not possible. This raises optimism that new ways may be discovered to explain change in SOC and increase SOC where it is possible in a beneficial way.

  14. Assimilation of SMOS Retrieved Soil Moisture into the Land Information System

    NASA Technical Reports Server (NTRS)

    Blankenship, Clay; Case, Jonathan; Zavodsky, Bradley; Jedlovec, Gary

    2014-01-01

    Soil moisture retrievals from the Soil Moisture and Ocean Salinity (SMOS) instrument are assimilated into the Noah land surface model (LSM) within the NASA Land Information System (LIS). Before assimilation, SMOS retrievals are bias-corrected to match the model climatological distribution using a Cumulative Distribution Function (CDF) matching approach. Data assimilation is done via the Ensemble Kalman Filter. The goal is to improve the representation of soil moisture within the LSM, and ultimately to improve numerical weather forecasts through better land surface initialization. We present a case study showing a large area of irrigation in the lower Mississippi River Valley, in an area with extensive rice agriculture. High soil moisture value in this region are observed by SMOS, but not captured in the forcing data. After assimilation, the model fields reflect the observed geographic patterns of soil moisture. Plans for a modeling experiment and operational use of the data are given. This work helps prepare for the assimilation of Soil Moisture Active/Passive (SMAP) retrievals in the near future.

  15. Representing life in the Earth system with soil microbial functional traits in the MIMICS model

    NASA Astrophysics Data System (ADS)

    Wieder, W. R.; Grandy, A. S.; Kallenbach, C. M.; Taylor, P. G.; Bonan, G. B.

    2015-02-01

    Projecting biogeochemical responses to global environmental change requires multi-scaled perspectives that consider organismal diversity, ecosystem processes and global fluxes. However, microbes, the drivers of soil organic matter decomposition and stabilization, remain notably absent from models used to project carbon cycle-climate feedbacks. We used a microbial trait-based soil carbon (C) model, with two physiologically distinct microbial communities to improve current estimates of soil C storage and their likely response to perturbations. Drawing from the application of functional traits used to model other ecosystems, we incorporate copiotrophic and oligotrophic microbial functional groups in the MIcrobial-MIneral Carbon Stabilization (MIMICS) model, which incorporates oligotrophic and copiotrophic functional groups, akin to "gleaner" vs. "opportunist" plankton in the ocean, or r vs. K strategists in plant and animals communities. Here we compare MIMICS to a conventional soil C model, DAYCENT, in cross-site comparisons of nitrogen (N) enrichment effects on soil C dynamics. MIMICS more accurately simulates C responses to N enrichment; moreover, it raises important hypotheses involving the roles of substrate availability, community-level enzyme induction, and microbial physiological responses in explaining various soil biogeochemical responses to N enrichment. In global-scale analyses, we show that current projections from Earth system models likely overestimate the strength of the land C sink in response to increasing C inputs with elevated carbon dioxide (CO2). Our findings illustrate that tradeoffs between theory and utility can be overcome to develop soil biogeochemistry models that evaluate and advance our theoretical understanding of microbial dynamics and soil biogeochemical responses to environmental change.

  16. Assimilation of SMOS Retrieved Soil Moisture into the Land Information System

    NASA Technical Reports Server (NTRS)

    Blankenship, Clay B.; Case, Jonathan L.; Zavodsky, Bradley T.

    2014-01-01

    Soil moisture is a crucial variable for weather prediction because of its influence on evaporation and surface heat fluxes. It is also of critical importance for drought and flood monitoring and prediction and for public health applications such as monitoring vector-borne diseases. Land surface modeling benefits greatly from regular updates with soil moisture observations via data assimilation. Satellite remote sensing is the only practical observation type for this purpose in most areas due to its worldwide coverage. The newest operational satellite sensor for soil moisture is the Microwave Imaging Radiometer using Aperture Synthesis (MIRAS) instrument aboard the Soil Moisture and Ocean Salinity (SMOS) satellite. The NASA Short-term Prediction Research and Transition Center (SPoRT) has implemented the assimilation of SMOS soil moisture observations into the NASA Land Information System (LIS), an integrated modeling and data assimilation software platform. We present results from assimilating SMOS observations into the Noah 3.2 land surface model within LIS. The SMOS MIRAS is an L-band radiometer launched by the European Space Agency in 2009, from which we assimilate Level 2 retrievals [1] into LIS-Noah. The measurements are sensitive to soil moisture concentration in roughly the top 2.5 cm of soil. The retrievals have a target volumetric accuracy of 4% at a resolution of 35-50 km. Sensitivity is reduced where precipitation, snowcover, frozen soil, or dense vegetation is present. Due to the satellite's polar orbit, the instrument achieves global coverage twice daily at most mid- and low-latitude locations, with only small gaps between swaths.

  17. Structure, composition and metagenomic profile of soil microbiomes associated to agricultural land use and tillage systems in Argentine Pampas.

    PubMed

    Carbonetto, Belén; Rascovan, Nicolás; Álvarez, Roberto; Mentaberry, Alejandro; Vázquez, Martin P

    2014-01-01

    Agriculture is facing a major challenge nowadays: to increase crop production for food and energy while preserving ecosystem functioning and soil quality. Argentine Pampas is one of the main world producers of crops and one of the main adopters of conservation agriculture. Changes in soil chemical and physical properties of Pampas soils due to different tillage systems have been deeply studied. Still, not much evidence has been reported on the effects of agricultural practices on Pampas soil microbiomes. The aim of our study was to investigate the effects of agricultural land use on community structure, composition and metabolic profiles on soil microbiomes of Argentine Pampas. We also compared the effects associated to conventional practices with the effects of no-tillage systems. Our results confirmed the impact on microbiome structure and composition due to agricultural practices. The phyla Verrucomicrobia, Plactomycetes, Actinobacteria, and Chloroflexi were more abundant in non cultivated soils while Gemmatimonadetes, Nitrospirae and WS3 were more abundant in cultivated soils. Effects on metabolic metagenomic profiles were also observed. The relative abundance of genes assigned to transcription, protein modification, nucleotide transport and metabolism, wall and membrane biogenesis and intracellular trafficking and secretion were higher in cultivated fertilized soils than in non cultivated soils. We also observed significant differences in microbiome structure and taxonomic composition between soils under conventional and no-tillage systems. Overall, our results suggest that agronomical land use and the type of tillage system have induced microbiomes to shift their life-history strategies. Microbiomes of cultivated fertilized soils (i.e. higher nutrient amendment) presented tendencies to copiotrophy while microbiomes of non cultivated homogenous soils appeared to have a more oligotrophic life-style. Additionally, we propose that conventional tillage systems may

  18. Structure, composition and metagenomic profile of soil microbiomes associated to agricultural land use and tillage systems in Argentine Pampas.

    PubMed

    Carbonetto, Belén; Rascovan, Nicolás; Álvarez, Roberto; Mentaberry, Alejandro; Vázquez, Martin P

    2014-01-01

    Agriculture is facing a major challenge nowadays: to increase crop production for food and energy while preserving ecosystem functioning and soil quality. Argentine Pampas is one of the main world producers of crops and one of the main adopters of conservation agriculture. Changes in soil chemical and physical properties of Pampas soils due to different tillage systems have been deeply studied. Still, not much evidence has been reported on the effects of agricultural practices on Pampas soil microbiomes. The aim of our study was to investigate the effects of agricultural land use on community structure, composition and metabolic profiles on soil microbiomes of Argentine Pampas. We also compared the effects associated to conventional practices with the effects of no-tillage systems. Our results confirmed the impact on microbiome structure and composition due to agricultural practices. The phyla Verrucomicrobia, Plactomycetes, Actinobacteria, and Chloroflexi were more abundant in non cultivated soils while Gemmatimonadetes, Nitrospirae and WS3 were more abundant in cultivated soils. Effects on metabolic metagenomic profiles were also observed. The relative abundance of genes assigned to transcription, protein modification, nucleotide transport and metabolism, wall and membrane biogenesis and intracellular trafficking and secretion were higher in cultivated fertilized soils than in non cultivated soils. We also observed significant differences in microbiome structure and taxonomic composition between soils under conventional and no-tillage systems. Overall, our results suggest that agronomical land use and the type of tillage system have induced microbiomes to shift their life-history strategies. Microbiomes of cultivated fertilized soils (i.e. higher nutrient amendment) presented tendencies to copiotrophy while microbiomes of non cultivated homogenous soils appeared to have a more oligotrophic life-style. Additionally, we propose that conventional tillage systems may

  19. Structure, Composition and Metagenomic Profile of Soil Microbiomes Associated to Agricultural Land Use and Tillage Systems in Argentine Pampas

    PubMed Central

    Carbonetto, Belén; Rascovan, Nicolás; Álvarez, Roberto; Mentaberry, Alejandro; Vázquez, Martin P.

    2014-01-01

    Agriculture is facing a major challenge nowadays: to increase crop production for food and energy while preserving ecosystem functioning and soil quality. Argentine Pampas is one of the main world producers of crops and one of the main adopters of conservation agriculture. Changes in soil chemical and physical properties of Pampas soils due to different tillage systems have been deeply studied. Still, not much evidence has been reported on the effects of agricultural practices on Pampas soil microbiomes. The aim of our study was to investigate the effects of agricultural land use on community structure, composition and metabolic profiles on soil microbiomes of Argentine Pampas. We also compared the effects associated to conventional practices with the effects of no-tillage systems. Our results confirmed the impact on microbiome structure and composition due to agricultural practices. The phyla Verrucomicrobia, Plactomycetes, Actinobacteria, and Chloroflexi were more abundant in non cultivated soils while Gemmatimonadetes, Nitrospirae and WS3 were more abundant in cultivated soils. Effects on metabolic metagenomic profiles were also observed. The relative abundance of genes assigned to transcription, protein modification, nucleotide transport and metabolism, wall and membrane biogenesis and intracellular trafficking and secretion were higher in cultivated fertilized soils than in non cultivated soils. We also observed significant differences in microbiome structure and taxonomic composition between soils under conventional and no- tillage systems. Overall, our results suggest that agronomical land use and the type of tillage system have induced microbiomes to shift their life-history strategies. Microbiomes of cultivated fertilized soils (i.e. higher nutrient amendment) presented tendencies to copiotrophy while microbiomes of non cultivated homogenous soils appeared to have a more oligotrophic life-style. Additionally, we propose that conventional tillage systems

  20. Seasonal dynamics of CO2 efflux in soils amended with composted and thermally-dried sludge as affected by soil tillage systems in a semi-arid agroecosystem

    NASA Astrophysics Data System (ADS)

    García-Gil, Juan Carlos; Soler-Rovira, Pedro; López-de-Sa, Esther G.; Polo, Alfredo

    2014-05-01

    In semi-arid agricultural soils, seasonal dynamic of soil CO2 efflux (SCE) is highly variable. Based on soil respiration measurements the effects of different management systems (moldboard plowing, chisel and no-tillage) and the application of composted sludge (CS) and thermally-dried sewage sludge (TSS) was investigated in a long-term field experiment (28 years) conducted on a sandy-loam soil at the experimental station 'La Higueruela' (40o 03'N, 4o 24'W). Both organic amendments were applied at a rate of 30 Mg ha-1 prior to tillage practices. Unamended soils were used as control for each tillage system. SCE was moderate in late spring (2.2-11.8 μmol CO2 m-2 s-1) when amendments were applied and tillage was performed, markedly decreased in summer (0.4-3.2 μmol CO2 m-2 s-1), following a moderate increase in autumn (3.4-14.1 μmol CO2 m-2 s-1), rising sharply in October (5.6-39.8 μmol CO2 m-2 s-1 ). In winter, SCE was low (0.6-6.5 μmol CO2 m-2 s-1). In general, SCE was greater in chisel and moldboard tilled soils, and in CS and particularly TSS-amended soils, due to the addition of labile C with these amendments, meanwhile no-tillage soils exhibited smaller increases in C efflux throughout the seasons. Soil temperature controlled the seasonal variations of SCE. In summer, when drought occurs, a general decrease of SCE was observed due to a deficit in soil water content. After drought period SCE jumped to high values in response to rain events ('Birch effect') that changed soil moisture conditions. Soil drying in summer and rewetting in autumn may promotes some changes on the structure of soil microbial community, affecting associated metabolic processes, and enhancing a rapid mineralization of water-soluble organic C compounds and/or dead microbial biomass that acts as an energy source for soil microorganisms. To assess the effects of tillage and amendments on SCE, Q10 values were calculated. Data were grouped into three groups according to soil moisture (0

  1. Comparative analysis of seismic response characteristics of pile-soil-structure interaction system

    NASA Astrophysics Data System (ADS)

    Kong, Desen; Luan, Maotian; Wang, Weiming

    2006-01-01

    The study on the earthquake-resistant performance of a pile-soil-structure interaction system is a relatively complicated and primarily important issue in civil engineering practice. In this paper, a computational model and computation procedures for pile-supported structures, which can duly consider the pile-soil interaction effect, are established by the finite element method. Numerical implementation is made in the time domain. A simplified approximation for the seismic response analysis of pile-soil-structure systems is briefly presented. Then a comparative study is performed for an engineering example with numerical results computed respectively by the finite element method and the simplified method. Through comparative analysis, it is shown that the results obtained by the simplified method well agree with those achieved by the finite element method. The numerical results and findings will offer instructive guidelines for earthquake-resistant analysis and design of pile-supported structures.

  2. Effect of soil-rock system on speleothems weathering in Bailong Cave, Yunnan Province, China*

    PubMed Central

    Wang, Jing; Song, Lin-hua

    2005-01-01

    Bailong Cave with its well-developed Middle Triassic calcareous dolomite’s system was opened as a show cave for visitors in 1988. The speleothem scenery has been strongly weathered as white powder on the outer layers. Study of the cave winds, permeability of soil-rock system and the chemical compositions of the dripping water indicated: (1) The cave dimension structure distinctively affects the cave winds, which were stronger at narrow places. (2) Based on the different soil grain size distribution, clay was the highest in composition in the soil. The response sense of dripping water to the rainwater percolation was slow. The density of joints and other openings in dolomite make the dolomite as mesh seepage body forming piles of thin and high columns and stalactites. (3) Study of 9 dripping water samples by HYDROWIN computer program showed that the major mineral in the water was dolomite. PMID:15682505

  3. Effect of soil-rock system on speleothems weathering in Bailong Cave, Yunnan Province, China.

    PubMed

    Wang, Jing; Song, Lin-Hua

    2005-03-01

    Bailong Cave with its well-developed Middle Triassic calcareous dolomite's system was opened as a show cave for visitors in 1988. The speleothem scenery has been strongly weathered as white powder on the outer layers. Study of the cave winds, permeability of soil-rock system and the chemical compositions of the dripping water indicated: (1) The cave dimension structure distinctively affects the cave winds, which were stronger at narrow places. (2) Based on the different soil grain size distribution, clay was the highest in composition in the soil. The response sense of dripping water to the rainwater percolation was slow. The density of joints and other openings in dolomite make the dolomite as mesh seepage body forming piles of thin and high columns and stalactites. (3) Study of 9 dripping water samples by HYDROWIN computer program showed that the major mineral in the water was dolomite.

  4. Dynamics of Zn in an urban wetland soil-plant system: Coupling isotopic and EXAFS approaches

    NASA Astrophysics Data System (ADS)

    Aucour, Anne-Marie; Bedell, Jean-Philippe; Queyron, Marine; Magnin, Valérie; Testemale, Denis; Sarret, Géraldine

    2015-07-01

    Plants play a key role in the stabilization of metals in contaminated environments. Studies have been performed on Zn uptake and storage mechanisms, mainly for Zn hyperaccumulating plants, though less is known about Zn stabilization in the rhizosphere of non-accumulating plants. This study was focused on the dynamics of Zn in a whole soil-litter-plant system and the processes controlling Zn mobilization and stabilization. The site studied was an infiltration basin receiving urban stormwater, in which Phalaris arundinacea (reed canary grass) developed spontaneously. A combination of chemical extractions (CaCl2, DTPA), EXAFS spectroscopy and Zn stable isotope measurements was applied for the water inlet, soil, plant organs and decaying biomass. Zn speciation changed from the water inlet to the soil. In the soil, Zn was present as Zn-layered double hydroxide (Zn-LDH), tetrahedral and octahedral sorbed Zn species. The formation of Zn-LDH participates in Zn stabilization. Tetrahedral Zn species, which were partly DTPA exchangeable, were enriched in heavy isotopes, whereas octahedral Zn (Zn-LDH and sorbed species) were enriched in light isotopes. Based on a linear model between δ66Zn and Zn speciation, δ66Zn for pure tetrahedral and octahedral end-members were estimated at ca. 0.33‰ and 0.04‰, respectively. In the plant, a mixture of octahedral Zn (attributed to aqueous Zn-organic acid complexes present in the symplasm), and tetrahedral Zn (attributed to apoplasmic Zn-cell wall complexes) was observed in all organs. Large enrichment in light isotopes from the soil to the plant Δ66Zn (of ca. -0.6‰) was observed. The stem was enriched in light isotopes versus roots and, to a lesser extent, versus leaves. The results suggest that Zn was taken up via a low-affinity transport system and that Zn was sequestrated in the stem symplasm after transit through leaves. Finally, intense Zn exchanges were observed between the decaying biomass and the soil, with the sorption of

  5. Emissions of N2O from peat soils under different cropping systems

    NASA Astrophysics Data System (ADS)

    Norberg, Lisbet; Berglund, Örjan; Berglund, Kerstin

    2016-04-01

    Drainage of peatlands for agriculture use leads to an increase in nitrogen turnover rate causing emissions of N2O to the atmosphere. Agriculture contributes to a substantial part of the anthropogenic emissions of N2O therefore mitigation options for the farmers are important. Here we present a field study with the aim to investigate if the choice of cropping system can mitigate the emission of N2O from cultivated organic soils. The sites used in the study represent fen peat soils with a range of different soil properties located in different parts of southern Sweden. All sites are on active farms with good drainage. N2O emissions from the soil under two different crops grown on the same field, with the same soil type, drainage intensity and weather conditions, are compared by gas sampling. The crops included are oat, barley, carrot, potato and grassland. Three or four sampling occasions during the growing season in 2010 were carried out with static chambers. The N2O emission is calculated from the linear increase of gas concentration in the chamber headspace during the incubation time of 40 minutes. Parallel to the gas sampling soil temperature and soil moisture are measured and some soil properties determined. The result from the gas sampling and measurements show no significant difference in seasonal average N2O emission between the compared crops at any site. There are significant differences in N2O emissions between the compared crops at some of the single sampling occasions but the result vary and no crop can be pointed out as a mitigation option. The seasonal average N2O emissions varies from 16±17 to 1319±1971 μg N2O/m2/h with peaks up to 3317 μg N2O/m2/h. The N2O emission rate from peat soils are determined by other factors than the type of crops grown on the field. The emission rates vary during the season and especially between sites. Although all sites are fen peat soil the soil properties are different, e.g. carbon content varies between 27-43% and

  6. Biochar increases plant available water in a sandy soil under an aerobic rice cropping system

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  7. Effect of biochar and liming on soil nitrous oxide emissions from a temperate maize cropping system

    NASA Astrophysics Data System (ADS)

    Hüppi, R.; Felber, R.; Neftel, A.; Six, J.; Leifeld, J.

    2015-12-01

    Biochar, a carbon-rich, porous pyrolysis product of organic residues may positively affect plant yield and can, owing to its inherent stability, promote soil carbon sequestration when amended to agricultural soils. Another possible effect of biochar is the reduction in emissions of nitrous oxide (N2O). A number of laboratory incubations have shown significantly reduced N2O emissions from soil when mixed with biochar. Emission measurements under field conditions however are more scarce and show weaker or no reductions, or even increases in N2O emissions. One of the hypothesised mechanisms for reduced N2O emissions from soil is owing to the increase in soil pH following the application of alkaline biochar. To test the effect of biochar on N2O emissions in a temperate maize cropping system, we set up a field trial with a 20t ha-1 biochar treatment, a limestone treatment adjusted to the same pH as the biochar treatment (pH 6.5), and a control treatment without any addition (pH 6.1). An automated static chamber system measured N2O emissions for each replicate plot (n = 3) every 3.6 h over the course of 8 months. The field was conventionally fertilised at a rate of 160 kg N ha-1 in three applications of 40, 80 and 40 kg N ha-1 as ammonium nitrate. Cumulative N2O emissions were 52 % smaller in the biochar compared to the control treatment. However, the effect of the treatments overall was not statistically significant (p = 0.27) because of the large variability in the data set. Limed soils emitted similar mean cumulative amounts of N2O as the control. There is no evidence that reduced N2O emissions with biochar relative to the control is solely caused by a higher soil pH.

  8. Fate and Transport of Acrylamide in Soil and Groundwater Systems: Sorption, Retardation and Numerical Simulations

    NASA Astrophysics Data System (ADS)

    Arrowood, T.; Young, M.; Yu, Z.; Labahn, S.; Moser, D.

    2007-12-01

    Acrylamide (AMD) is a known animal and suspected human carcinogen and is used to produce polyacrylamide (PAM), which has been proposed as a technology for seepage control in unlined water delivery canals. The fate and transport of AMD in groundwater systems is not well known, and previous studies have not quantified the sorption coefficient (Kd), sorption isotherms, or estimated AMD breakthrough and transport parameters in soil and water systems. In this study, batch experiments and repacked soil column tests were conducted on three soils (a control sand, and field collected sand and loam soils) to determine the Kd, retardation factor and the form of the sorption isotherm. A numerical model (HYDRUS 2D) was used to simulate a canal environment using the fate and transport parameters of AMD obtained in the laboratory. Microbial degradation rates, obtained from a companion study (Labahn et al. 2007) were used in the model. Photodegradation rates for AMD were also considered. Results from batch studies indicate a Freundlich-type sorption isotherm for AMD in the loam soil. Sorption in the sands was not significant. The preliminary results for the soil column tests show that AMD is conservative in all three types of soil tested with retardation (R) values ranging from 0.985-1.072, with most column studies showing 0.99

  9. [Continuous remediation of heavy metal contaminated soil by co-cropping system enhanced with chelator].

    PubMed

    Wei, Ze-Bin; Guo, Xiao-Fang; Wu, Qi-Tang; Long, Xin-Xian

    2014-11-01

    In order to elucidate the continuous effectiveness of co-cropping system coupling with chelator enhancement in remediating heavy metal contaminated soils and its environmental risk towards underground water, soil lysimeter (0.9 m x 0.9 m x 0.9 m) experiments were conducted using a paddy soil affected by Pb and Zn mining in Lechang district of Guangdong Province, 7 successive crops were conducted for about 2.5 years. The treatments included mono-crop of Sedum alfredii Hance (Zn and Cd hyperaccumulator), mono-crop of corn (Zea mays, cv. Yunshi-5, a low-accumulating cultivar), co-crop of S. alfredii and corn, and co-crop + MC (Mixture of Chelators, comprised of citric acid, monosodium glutamate waste liquid, EDTA and KCI with molar ratio of 10: 1:2:3 at the concentration of 5 mmol x kg(-1) soil). The changes of heavy metal concentrations in plants, soil and underground water were monitored. Results showed that the co-cropping system was suitable only in spring-summer seasons and significantly increased Zn and Cd phytoextraction. In autumn-winter seasons, the growth of S. alfredii and its phytoextraction of Zn and Cd were reduced by co-cropping and MC application. In total, the mono-crops of S. alfredii recorded a highest phytoextraction of Zn and Cd. However, the greatest reduction of soil Zn, Cd and Pb was observed with the co-crop + MC treatment, the reduction rates were 28%, 50%, and 22%, respectively, relative to the initial soil metal content. The reduction of this treatment was mainly attributed to the downwards leaching of metals to the subsoil caused by MC application. The continuous monitoring of leachates during 2. 5 year's experiment also revealed that the addition of MC increased heavy metal concentrations in the leaching water, but they did not significantly exceed the III grade limits of the underground water standard of China.

  10. Behavior and impact of zirconium in the soil-plant system: plant uptake and phytotoxicity.

    PubMed

    Shahid, Muhammad; Ferrand, Emmanuel; Schreck, Eva; Dumat, Camille

    2013-01-01

    Zirconium (Zr) is a transition metal that has both stable and radioactive isotopes.This metal has gained significant attention as a major pollutant of concern, partly because it has been prominent in the debate concerning the growing anthropogenic pressure on the environment. Its numerous past and present uses have induced significant soil and water pollution. Zr is generally considered to have low mobility in soils. The behavior of Zr particularly depends on the characteristics of the media in which it exists, and even its presence in the biosphere as a contaminate may affect its behavior. In this chapter, we describe the relationship between the behavior of Zrand its speciation in soils, its uptake and accumulation by plants, its translocation and toxicity inside plants, and mechanisms by which plants detoxify it.Zr is abundant and occurs naturally in the earth's crust. Zr emissions to the atmosphere are increasing from anthropogenic activities such as its use in industry and nuclear reactors. Zr forms various complexes with soil components, which reduces its soil mobility and phytoavailabilty. The mobility and phytoavailabilty of Zr in soil depend on its speciation and the physicochemical properties of soil that include soil pH, texture, and organic contents. Despite having low soil mobility and phytoavailability,amounts of Zr are absorbed by plants, mainly through the root system and can thereby enter the food chain.After plant uptake, Zr mainly accumulates in root cells. Zr does not have any known essential function in plant or animal metabolism. Although little published data are available, we conclude that the phytotoxicity of Zr is generally low.Notwithstanding, Zr can significantly reduce plant growth and can affect plantenzyme activity. When exposed to Zr-induced toxicity, plants possess numerous defense mechanisms to cope with the toxicity. Such strategies include Zr sequestration in plant roots and activation of various antioxidants. Because Zr may have

  11. Isotopic Composition of Organic and Inorganic Carbon in Desert Biological Soil Crust Systems

    NASA Astrophysics Data System (ADS)

    Alexander, K.; Hartnett, H.; Anbar, A.; Beraldi, H.; Garcia-Pichel, F.

    2006-12-01

    Biological soil crusts (BSCs) are microbial communities that colonize soil surfaces in many arid regions. BSCs are important sources for fixed carbon and nitrogen in these ecosystems, and they greatly influence the structure, function, and appearance of desert soils. Biological activity of BSCs occurs during pulses of hydration requiring desert crusts to tolerate extremes in UV radiation, temperature, and desiccation. These characteristics make desert crusts unique systems that have received little consideration in the study of biogeochemical processes in extreme environments. This project investigates the impact of BSCs on carbon dynamics within desert soils. Soil cores ranging in depth from 8 to 12 cm were taken in March, 2006 from deserts near Moab, Utah. Two major BSC classes were identified: lichen-dominated (dark and pinnacled) soil crusts and cyanobacteria-dominated (light and flat) soil crusts. These two surface morphologies are related to the different biological communities. Carbon content and stable carbon isotopic composition were determined for the bulk carbon pool, as well as for the organic and inorganic carbon fractions of the soils. Expectedly, there was a net decrease in organic carbon content with depth (0.39-0.27 percent). Stable carbon isotope values for the organic fraction ranged from -5.8 per mil to -24.0 per mil (Avg: -14.4 per mil, S.D: 6.42 per mil). Stable carbon isotope values for the inorganic fraction ranged from 0.3 per mil to -3.6 per mil (Avg: -2.4 per mil, S.D.: 1.05 per mil). The variation in the isotopic composition of the organic carbon was due to a strong depletion below the surface soil value occurring between 3 and 5 cm depth, with an enrichment above the original surface value at depths below 6 to 10 cm. These data suggest that within desert soil crust systems the carbon isotopic signal is complex with both a clear biological imprint (lighter organic carbon) as well as evidence for some mechanism that results in

  12. Soil Modification by Native Shrubs Boosts Crop Productivity in Sudano-Sahelian Agroforestry System

    NASA Astrophysics Data System (ADS)

    Bogie, N. A.; Bayala, R.; Diedhiou, I.; Ghezzehei, T. A.; Dick, R.

    2014-12-01

    A changing climate along with human and animal population pressure can have a devastating effect on crop yields and food security in the Sudano-Sahel. Agricultural solutions to address soil degradation and crop water stress are needed to combat this increasingly difficult situation. Significant differences in crop success have been observed in peanut and millet grown in association with two native evergreen shrubs Piliostigma reticulatum, and Guiera senegalensis at the sites of Nioro du Rip and Keur Matar, respectively.We investigate how farmers can increase crop productivity by capitalizing on the evolutionary adaptation of native shrubs to the harsh Sudano-Sahelian environment as well as the physical mechanisms at work in the system that can lead to more robust yields. Soil moisture and water potential data were collected during a dry season millet irrigation experiment where stress was imposed in the intercropped system. Despite lower soil moisture content, crops grown in association with shrubs have increased biomass production and a faster development cycle. Hydraulic redistribution is thought to exist in this system and we found diurnal fluctuations in water potential within the intercropped system that increased in magnitude of to 0.4 Mpa per day as the soil dried below 1.0 Mpa during the stress treatment. An isotopic tracer study investigating hydraulic redistribution was carried out by injecting labeled water into shrub roots and sampling shrubs and nearby crops for isotopic analysis of plant water. These findings build on work that was completed in 2004 at the site, but point to lower overall magnitude of diurnal soil water potential fluctuations in dry soils. Using even the limited resources that farmers possess, this agroforestry technique can be expanded over wide swaths of the Sahel.

  13. Determination of water absorption and water holding capacities of different soil mixtures with MINIDRAIN system to enhance the plant growth

    NASA Astrophysics Data System (ADS)

    Sudan Acharya, Madhu; Rauchecker, Markus; Wu, Wei

    2014-05-01

    Soil water holding capacity is the amount of water that a given soil can hold against the force of gravity. Soil texture and organic matter are the key components that determine soil water holding capacity. Soils with smaller particle sizes, such as silt and clay have larger surface area can hold more water compared to sand which has large particle sizes which results in smaller surface area. A study report showed that 1% increase in soil humus will result in a 4% increase in stored soil water (Morris, 2004) and 1 part humus holds 4 parts of water (Wheeler and Ward, 1998). Therefore, the more humus that can be added to the soil, the greater the water holding capacity of the soil. As the level of organic matter increases in a soil, the water holding capacity also increases due to the affinity of organic matter for water. The water holding capacity of the soil is determined by the amount of water held in the soil sample vs. the dry weight of the sample. MINIDRAIN is a patented system made of geo-fabric (fleece) or combination of geosynthetics and humus. MINIDRAIN and vegetation nets developed by the company ÖKO-TEX (Linz, Austria) will improve the distribution of water and air in the soils, increase the growth of vegetation and reduce the soil erosion. Depending on the physical configuration, there are four different combinations of MINIDRAIN systems developed by ÖKO-TEX. a) Geotextile (fleece) strips of different sizes (e.g. 5x10x250 mm) b) Net formed strips (drainage nets) of different sizes c) Multilayer geotextile mats with humus, seeds or compost of different sizes (e.g. 10x30x200 mm) d) Multilayer geotextile net formed mats with humus, seeds or compost This paper describes the experimental results of the water absorption and water holding capacity of different forms of MINIDRAIN under different soil mixes. In this experiment, potting soil, coarse sand and LECA (Light weight clay aggregates) balls are mixed with different proportion of MINIDRAIN systems and

  14. Characteristics of heavy metal transfer and their influencing factors in different soil-crop systems of the industrialization region, China.

    PubMed

    Chen, Hongyan; Yuan, Xuyin; Li, Tianyuan; Hu, Sun; Ji, Junfeng; Wang, Cheng

    2016-04-01

    Soil heavy metals and their bioaccumulation in agricultural products have attracted widespread concerns, yet the transfer and accumulation characteristics of heavy metals in different soil-crop systems was rarely investigated. Soil and crop samples were collected from the typical agricultural areas in the Yangtze River Delta region, China. The concentrations of Cu, Pb, Zn, Cd and Hg in the soils, roots and grains of rice (Oryza Sativa L.), wheat (Triticum L.) and canola (Brassica napus L.) were determined in this study. Transfer ability of heavy metals in soil-rice system was stronger than those in soil-wheat and soil-canola systems. The wheat showed a strong capacity to transfer Zn, Cu and Cd from root to the grain while canola presented a restricting effect to the intake of Cu and Cd. Soil pH and total organic matter were major factors influencing metal transfer from soil to rice, whereas soil Al2O3 contents presented a negative effect on heavy metal mobility in wheat and canola cultivation systems. The concentration of Zn and Cd in crop grains could well predicted according to the stepwise multiple linear regression models, which could help to quantitatively evaluate the ecologic risk of heavy metal accumulation in crops in the study area.

  15. Impact of Wheat/Faba Bean Mixed Cropping or Rotation Systems on Soil Microbial Functionalities

    PubMed Central

    Wahbi, Sanâa; Prin, Yves; Thioulouse, Jean; Sanguin, Hervé; Baudoin, Ezékiel; Maghraoui, Tasnime; Oufdou, Khalid; Le Roux, Christine; Galiana, Antoine; Hafidi, Mohamed; Duponnois, Robin

    2016-01-01

    Cropping systems based on carefully designed species mixtures reveal many potential advantages in terms of enhancing crop productivity, reducing pest and diseases, and enhancing ecological services. Associating cereals and legume production either through intercropping or rotations might be a relevant strategy of producing both type of culture, while benefiting from combined nitrogen fixed by the legume through its symbiotic association with nitrogen-fixing bacteria, and from a better use of P and water through mycorrhizal associations. These practices also participate to the diversification of agricultural productions, enabling to secure the regularity of income returns across the seasonal and climatic uncertainties. In this context, we designed a field experiment aiming to estimate the 2 years impact of these practices on wheat yield and on soil microbial activities as estimated through Substrate Induced Respiration method and mycorrhizal soil infectivity (MSI) measurement. It is expected that understanding soil microbial functionalities in response to these agricultural practices might allows to target the best type of combination, in regard to crop productivity. We found that the tested cropping systems largely impacted soil microbial functionalities and MSI. Intercropping gave better results in terms of crop productivity than the rotation practice after two cropping seasons. Benefits resulting from intercrop should be highly linked with changes recorded on soil microbial functionalities. PMID:27695462

  16. Impact of Wheat/Faba Bean Mixed Cropping or Rotation Systems on Soil Microbial Functionalities

    PubMed Central

    Wahbi, Sanâa; Prin, Yves; Thioulouse, Jean; Sanguin, Hervé; Baudoin, Ezékiel; Maghraoui, Tasnime; Oufdou, Khalid; Le Roux, Christine; Galiana, Antoine; Hafidi, Mohamed; Duponnois, Robin

    2016-01-01

    Cropping systems based on carefully designed species mixtures reveal many potential advantages in terms of enhancing crop productivity, reducing pest and diseases, and enhancing ecological services. Associating cereals and legume production either through intercropping or rotations might be a relevant strategy of producing both type of culture, while benefiting from combined nitrogen fixed by the legume through its symbiotic association with nitrogen-fixing bacteria, and from a better use of P and water through mycorrhizal associations. These practices also participate to the diversification of agricultural productions, enabling to secure the regularity of income returns across the seasonal and climatic uncertainties. In this context, we designed a field experiment aiming to estimate the 2 years impact of these practices on wheat yield and on soil microbial activities as estimated through Substrate Induced Respiration method and mycorrhizal soil infectivity (MSI) measurement. It is expected that understanding soil microbial functionalities in response to these agricultural practices might allows to target the best type of combination, in regard to crop productivity. We found that the tested cropping systems largely impacted soil microbial functionalities and MSI. Intercropping gave better results in terms of crop productivity than the rotation practice after two cropping seasons. Benefits resulting from intercrop should be highly linked with changes recorded on soil microbial functionalities.

  17. Removal of nitrogen by a layered soil infiltration system during intermittent storm events.

    PubMed

    Cho, Kang Woo; Song, Kyung Guen; Cho, Jin Woo; Kim, Tae Gyun; Ahn, Kyu Hong

    2009-07-01

    The fates of various nitrogen species were investigated in a layered biological infiltration system under an intermittently wetting regime. The layered system consisted of a mulch layer, coarse soil layer (CSL), and fine soil layer (FSL). The effects of soil texture were assessed focusing on the infiltration rate and the removal of inorganic nitrogen species. The infiltration rate drastically decreased when the uniformity coefficient was larger than four. The ammonium in the synthetic runoff was shown to be removed via adsorption during the stormwater dosing and nitrification during subsequent dry days. Stable ammonium adsorption was observed when the silt and clay content of CSL was greater than 3%. This study revealed that the nitrate leaching was caused by nitrification during dry days. Various patterns of nitrate flushing were observed depending on the soil configuration. The washout of nitrate was more severe as the silt/clay content of the CSL was greater. However, proper layering of soil proved to enhance the nitrate removal. Consequently, a strictly sandy CSL over FSL with a silt and clay content of 10% was the best configuration for the removal of ammonium and nitrate. PMID:19473686

  18. Sorption and mineral-promoted transformation of synthetic hormone growth promoters in soil systems.

    PubMed

    Qu, Shen; Kolodziej, Edward P; Cwiertny, David M

    2014-12-24

    This work examines the fate of synthetic growth promoters (trenbolone acetate, melengestrol acetate, and zeranol) in sterilized soil systems, focusing on their sorption to organic matter and propensity for mineral-promoted reactions. In organic-rich soil matrices (e.g., Pahokee Peat), the extent and reversibility of sorption did not generally correlate with compound hydrophobicity (e.g., K(ow) values), suggesting that specific binding interactions (e.g., potentially hydrogen bonding through C17 hydroxyl groups for the trenbolone and melengestrol families) can also contribute to uptake. In soils with lower organic carbon contents (1-5.9% OC), evidence supports sorption occurring in parallel with surface reaction on inorganic mineral phases. Subsequent experiments with pure mineral phases representative of those naturally abundant in soil (e.g., iron, silica, and manganese oxides) suggest that growth promoters are prone to mineral-promoted oxidation, hydrolysis, and/or nucleophilic (e.g., H2O or OH(-)) addition reactions. Although reaction products remain unidentified, this study shows that synthetic growth promoters can undergo abiotic transformation in soil systems, a previously unidentified fate pathway with implications for their persistence and ecosystem effects in the subsurface.

  19. Induction of systemic resistance in plants by biochar, a soil-applied carbon sequestering agent.

    PubMed

    Elad, Yigal; David, Dalia Rav; Harel, Yael Meller; Borenshtein, Menahem; Kalifa, Hananel Ben; Silber, Avner; Graber, Ellen R

    2010-09-01

    Biochar is the solid coproduct of biomass pyrolysis, a technique used for carbon-negative production of second-generation biofuels. The biochar can be applied as a soil amendment, where it permanently sequesters carbon from the atmosphere as well as improves soil tilth, nutrient retention, and crop productivity. In addition to its other benefits in soil, we found that soil-applied biochar induces systemic resistance to the foliar fungal pathogens Botrytis cinerea (gray mold) and Leveillula taurica (powdery mildew) on pepper and tomato and to the broad mite pest (Polyphagotarsonemus latus Banks) on pepper. Levels of 1 to 5% biochar in a soil and a coconut fiber-tuff potting medium were found to be significantly effective at suppressing both diseases in leaves of different ages. In long-term tests (105 days), pepper powdery mildew was significantly less severe in the biochar-treated plants than in the plants from the unamended controls although, during the final 25 days, the rate of disease development in the treatments and controls was similar. Possible biochar-related elicitors of systemic induced resistance are discussed.

  20. Effects of long-term use of different farming systems on some physical, chemical and microbiological parameters of soil quality

    NASA Astrophysics Data System (ADS)

    Gajda, Anna M.; Czyż, Ewa A.; Dexter, Anthony R.

    2016-04-01

    The aim of this study was to compare the effects of different farming systems (organic, integrated, conventional and monoculture) on some soil properties as: bulk density, contents of readily-dispersible clay, organic matter and particulate organic matter, and enzymatic activity measured in terms of the intensity of fluorescein diacetate hydrolysis. Soil under permanent grass was used as a control. The study was conducted on the 20 years lasting field experiment. Samples of Haplic Luvisol soil were collected twice a year on fields under winter wheat from the layers of 0-5, 5-10, 15-20, and 30-35 cm. Within arable soils the soil under organic farming contained the greatest amount of organic matter, which influenced strongly the readily-dispersible clay content, especially in the layer of 5-20 cm. The readily-dispersible clay content in soil under organic farming was 3 times lower, as compared to the conventional and monoculture farming. The highest contents of particulate organic matter 6.2 and 3.5 mg g-1 air dry soil, on average were measured in the 0-5 cm layer of control soil and soil under organic farming, respectively. Also, soil under organic farming and control soil from the depth of 0-5 cm showed 2-2.5 times greater activity of microorganisms in fluorescein diacetate hydrolysis than soil under conventional and monoculture farming. Increase of concentration of organic matter in soil under organic farming decreased soil bulk density. Statistical analysis showed significant correlations between studied parameters of soil quality and confirmed their effectiveness as indicators of disturbances in soil environment.

  1. GLO-Roots: an imaging platform enabling multidimensional characterization of soil-grown root systems.

    PubMed

    Rellán-Álvarez, Rubén; Lobet, Guillaume; Lindner, Heike; Pradier, Pierre-Luc; Sebastian, Jose; Yee, Muh-Ching; Geng, Yu; Trontin, Charlotte; LaRue, Therese; Schrager-Lavelle, Amanda; Haney, Cara H; Nieu, Rita; Maloof, Julin; Vogel, John P; Dinneny, José R

    2015-08-19

    Root systems develop different root types that individually sense cues from their local environment and integrate this information with systemic signals. This complex multi-dimensional amalgam of inputs enables continuous adjustment of root growth rates, direction, and metabolic activity that define a dynamic physical network. Current methods for analyzing root biology balance physiological relevance with imaging capability. To bridge this divide, we developed an integrated-imaging system called Growth and Luminescence Observatory for Roots (GLO-Roots) that uses luminescence-based reporters to enable studies of root architecture and gene expression patterns in soil-grown, light-shielded roots. We have developed image analysis algorithms that allow the spatial integration of soil properties, gene expression, and root system architecture traits. We propose GLO-Roots as a system that has great utility in presenting environmental stimuli to roots in ways that evoke natural adaptive responses and in providing tools for studying the multi-dimensional nature of such processes.

  2. Automated system for generation of soil moisture products for agricultural drought assessment

    NASA Astrophysics Data System (ADS)

    Raja Shekhar, S. S.; Chandrasekar, K.; Sesha Sai, M. V. R.; Diwakar, P. G.; Dadhwal, V. K.

    2014-11-01

    Drought is a frequently occurring disaster affecting lives of millions of people across the world every year. Several parameters, indices and models are being used globally to forecast / early warning of drought and monitoring drought for its prevalence, persistence and severity. Since drought is a complex phenomenon, large number of parameter/index need to be evaluated to sufficiently address the problem. It is a challenge to generate input parameters from different sources like space based data, ground data and collateral data in short intervals of time, where there may be limitation in terms of processing power, availability of domain expertise, specialized models & tools. In this study, effort has been made to automate the derivation of one of the important parameter in the drought studies viz Soil Moisture. Soil water balance bucket model is in vogue to arrive at soil moisture products, which is widely popular for its sensitivity to soil conditions and rainfall parameters. This model has been encoded into "Fish-Bone" architecture using COM technologies and Open Source libraries for best possible automation to fulfill the needs for a standard procedure of preparing input parameters and processing routines. The main aim of the system is to provide operational environment for generation of soil moisture products by facilitating users to concentrate on further enhancements and implementation of these parameters in related areas of research, without re-discovering the established models. Emphasis of the architecture is mainly based on available open source libraries for GIS and Raster IO operations for different file formats to ensure that the products can be widely distributed without the burden of any commercial dependencies. Further the system is automated to the extent of user free operations if required with inbuilt chain processing for every day generation of products at specified intervals. Operational software has inbuilt capabilities to automatically

  3. Soil nutrient dynamics in a perennial biomass production system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the upper Midwest, economic and social interests in bioenergy and low-carbon fuels are stimulating the conversion of cropland into perennial biomass systems. Landowners are embracing the change by developing diverse whole-farm management systems that can balance economic and environmental risk of...

  4. Unified Science Information Model for SoilSCAPE using the Mercury Metadata Search System

    NASA Astrophysics Data System (ADS)

    Devarakonda, Ranjeet; Lu, Kefa; Palanisamy, Giri; Cook, Robert; Santhana Vannan, Suresh; Moghaddam, Mahta Clewley, Dan; Silva, Agnelo; Akbar, Ruzbeh

    2013-12-01

    SoilSCAPE (Soil moisture Sensing Controller And oPtimal Estimator) introduces a new concept for a smart wireless sensor web technology for optimal measurements of surface-to-depth profiles of soil moisture using in-situ sensors. The objective is to enable a guided and adaptive sampling strategy for the in-situ sensor network to meet the measurement validation objectives of spaceborne soil moisture sensors such as the Soil Moisture Active Passive (SMAP) mission. This work is being carried out at the University of Michigan, the Massachusetts Institute of Technology, University of Southern California, and Oak Ridge National Laboratory. At Oak Ridge National Laboratory we are using Mercury metadata search system [1] for building a Unified Information System for the SoilSCAPE project. This unified portal primarily comprises three key pieces: Distributed Search/Discovery; Data Collections and Integration; and Data Dissemination. Mercury, a Federally funded software for metadata harvesting, indexing, and searching would be used for this module. Soil moisture data sources identified as part of this activity such as SoilSCAPE and FLUXNET (in-situ sensors), AirMOSS (airborne retrieval), SMAP (spaceborne retrieval), and are being indexed and maintained by Mercury. Mercury would be the central repository of data sources for cal/val for soil moisture studies and would provide a mechanism to identify additional data sources. Relevant metadata from existing inventories such as ORNL DAAC, USGS Clearinghouse, ARM, NASA ECHO, GCMD etc. would be brought in to this soil-moisture data search/discovery module. The SoilSCAPE [2] metadata records will also be published in broader metadata repositories such as GCMD, data.gov. Mercury can be configured to provide a single portal to soil moisture information contained in disparate data management systems located anywhere on the Internet. Mercury is able to extract, metadata systematically from HTML pages or XML files using a variety of

  5. TECHNOLOGY EVALUATION REPORT: BIOTROL SOIL WASHING SYSTEM FOR TREATMENT OF A WOOD PRESERVING SITE - VOLUME II

    EPA Science Inventory

    The SITE Program demonstration of one configuration of the BioTrol Soil Washing System (BSWS) was conducted to obtain reliable performance and cost data that can be used to evaluate the potential applicability of the technology as a remediation alternative for sites contaminated ...

  6. Hot background” of the mobile inelastic neutron scattering system for soil carbon analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The problem of gamma spectrum peaks identification arises when conducting soil carbon (and other elements) analysis using the mobile inelastic neutron scattering (MINS) system. Some gamma spectrum peaks could be associated with radioisotopes appearing due to neutron activation of both the MINS syste...

  7. Microbial community response to two water management systems for wetland rice production in high arsenic soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice cultivation on arsenic (As) impacted soils has recently garnered considerable attention. Rice plants can accumulate As in grain, especially under the continuously flooded conditions commonly utilized in wetland-rice production. However, recent studies have indicated that rice-management system...

  8. REMOVAL OF PCBS FROM A CONTAMINATED SOIL USING CF-SYSTEMS SOLVENT EXTRACTION PROCESS

    EPA Science Inventory

    The US EPA's START team in cooperation with EPA's SITE program evaluated a pilot scale solvent extraction process developed by CF-Systems. This process uses liquified propane to extract organic contaminants from soils, sludges, and sediments. A pilot-scale evaluation was conducte...

  9. BIOTROL SOIL WASHING SYSTEM FOR TREATMENT OF A WOOD PRESERVING SITE - APPLICATIONS ANALYSIS REPORT

    EPA Science Inventory

    The report analyzes the results of the SITE Program demonstration of BioTrol's Soil Washing System at the MacGillis & Gibbs wood treatment facility in New Brighton, MN. The contaminants of primary interest are pentachlorophenol (penta) and polynuclear aromatic hydrocarbons (PAHs)...

  10. Cover crops alter phosphorus soil fractions and organic matter accumulation in a Peruvian cacao agroforestry system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In many tropical soils, excessive weathering of primary minerals confounded by intense agricultural production has resulted in the depletion of organic matter and plant available forms of phosphorus (P). Long-term growth of cover crops in tropical agroforestry systems have been shown to influence nu...

  11. Proliferation of Escherichia coli O157:H7 in soil and hydroponic microgreen production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Radish (Raphanus sativus var. longipinnatus) microgreens were produced from seeds inoculated with Escherichia coli O157: H7 using soil substitute and hydroponic production systems. E. coli populations on the edible and inedible parts of harvested microgreen plants and in growth medium were examined....

  12. Influence of Cacao Genotypes on Soil Rhizosphere Biological Parameters Under Agro Forestry System

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Interactions of management systems and cacao genotypes have profound influence on the diversity of soil micro-fauna in the rhizosphere; and such changes may provide benefits to plant growth and development. Field experiment was established at Tarapoto, Peru during 2004 with 60 cacao genotypes in an ...

  13. An observing system simulation experiment (OSSE) for the aquarius/SAC-D soil moisture product

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An Observing System Simulation Experiment for the Aquarius/SAC-D mission has been developed for assessing the accuracy of soil moisture retrievals from passive L-band remote sensing. The implementation of the OSSE is based on: a 1-km land surface model over the Red-Arkansas River Basin, a forward mi...

  14. Soil health improvement in an organic orchard production system in Northwest Missouri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prairie Birthday Farm (PBF), a diversified, organic enterprise on the loess hill landscape in northwestern Missouri, was previously managed as a conventional corn-soybean production system. Transition to organic farming began in 1995 and included soil organic matter restoration with native prairie e...

  15. Greek Students Research the Effects of Fire on the Soil System through Project-Based Learning

    ERIC Educational Resources Information Center

    Kioupi, Vasiliki; Arianoutsou, Margarita

    2016-01-01

    This study is focused on the development, implementation and evaluation of an environmental education programme for secondary education students. The programme was entitled "?he effects of fire on the soil system" and it was implemented during the school period of 2008. Twenty-four (24) students (aged from 15 to 20) coming from Lidoriki…

  16. [Nitrification of biological soil crusts and soil system during drought process and its response to temperature and moisture: A case study in the Shapotou region, Northwest China].

    PubMed

    Xu, Bing-xin; Chen, Yong-le; Hu, Yi-gang; Zhang, Zhi-shan; Li, Gang; Li, Meng-ru; Chen, Dong

    2015-04-01

    Two types of soil covered by biological soil crusts (BSCs) , i.e. moss and algae, and moving sand in the natural vegetation area at the southeast fringe of the Tengger Desert were collected intactly. They were incubated continuously for 20 days under two different temperatures (15 degrees C and 25 degrees C) and moistures (10% and 25%) condition in the laboratory, and soil NO3(-)-N contents were measured after 1, 2, 5, 8, 12, 20 days of incubation and net nitrification rate was evaluated during dehydration. The results showed that NO3(-)-N content of the moss-covered soil (2.29 mg x kg(-1)) was higher than that of the algae-covered soil (1.84 mg x kg(-1)) and sand (1.59 mg x kg(-1)). Net nitrification rate of the three soil types ranged from -3.47 to 2.97 mg x kg(-1) x d(-1). For the moss-covered soil and algae-covered soil at 10% and 25% moisture levels, the net nitrification rates at 15 degrees C were 75.1%, 0.7% and 99.1%, 21.3% higher than those at 25 degrees C, respectively. Also, the net nitrification rates at 15 degrees C and 10% moisture levels were 193.4% and 107.3% higher than those at 25 degrees C and 25% moisture levels, respectively. The results suggested that regardless of soil moisture increasing or decreasing under the global warming senior, the net nitrification rate of BSCs-soil system in the desert would probably be limited to some extent during drought process.

  17. [Nitrification of biological soil crusts and soil system during drought process and its response to temperature and moisture: A case study in the Shapotou region, Northwest China].

    PubMed

    Xu, Bing-xin; Chen, Yong-le; Hu, Yi-gang; Zhang, Zhi-shan; Li, Gang; Li, Meng-ru; Chen, Dong

    2015-04-01

    Two types of soil covered by biological soil crusts (BSCs) , i.e. moss and algae, and moving sand in the natural vegetation area at the southeast fringe of the Tengger Desert were collected intactly. They were incubated continuously for 20 days under two different temperatures (15 degrees C and 25 degrees C) and moistures (10% and 25%) condition in the laboratory, and soil NO3(-)-N contents were measured after 1, 2, 5, 8, 12, 20 days of incubation and net nitrification rate was evaluated during dehydration. The results showed that NO3(-)-N content of the moss-covered soil (2.29 mg x kg(-1)) was higher than that of the algae-covered soil (1.84 mg x kg(-1)) and sand (1.59 mg x kg(-1)). Net nitrification rate of the three soil types ranged from -3.47 to 2.97 mg x kg(-1) x d(-1). For the moss-covered soil and algae-covered soil at 10% and 25% moisture levels, the net nitrification rates at 15 degrees C were 75.1%, 0.7% and 99.1%, 21.3% higher than those at 25 degrees C, respectively. Also, the net nitrification rates at 15 degrees C and 10% moisture levels were 193.4% and 107.3% higher than those at 25 degrees C and 25% moisture levels, respectively. The results suggested that regardless of soil moisture increasing or decreasing under the global warming senior, the net nitrification rate of BSCs-soil system in the desert would probably be limited to some extent during drought process. PMID:26288862

  18. Managing soil microbial communities in grain production systems through cropping practices

    NASA Astrophysics Data System (ADS)

    Gupta, Vadakattu

    2013-04-01

    Cropping practices can significantly influence the composition and activity of soil microbial communities with consequences to plant growth and production. Plant type can affect functional capacity of different groups of biota in the soil surrounding their roots, rhizosphere, influencing plant nutrition, beneficial symbioses, pests and diseases and overall plant health and crop production. The interaction between different players in the rhizosphere is due to the plethora of carbon and nutritional compounds, root-specific chemical signals and growth regulators that originate from the plant and are modulated by the physico-chemical properties of soils. A number of plant and environmental factors and management practices can influence the quantity and quality of rhizodeposition and in turn affect the composition of rhizosphere biota communities, microbe-fauna interactions and biological processes. Some of the examples of rhizosphere interactions that are currently considered important are: proliferation of plant and variety specific genera or groups of microbiota, induction of genes involved in symbiosis and virulence, promoter activity in biocontrol agents and genes correlated with root adhesion and border cell quality and quantity. The observation of variety-based differences in rhizodeposition and associated changes in rhizosphere microbial diversity and function suggests the possibility for the development of varieties with specific root-microbe interactions targeted for soil type and environment i.e. designer rhizospheres. Spatial location of microorganisms in the heterogeneous field soil matrix can have significant impacts on biological processes. Therefore, for rhizosphere research to be effective in variable seasonal climate and soil conditions, it must be evaluated in the field and within a farming systems context. With the current focus on security of food to feed the growing global populations through sustainable agricultural production systems there is a

  19. Multivariate analysis and visualization of soil quality data for no-till systems.

    PubMed

    Villamil, M B; Miguez, F E; Bollero, G A

    2008-01-01

    To evidence the multidimensionality of the soil quality concept, we propose the use of data visualization as a tool for exploratory data analyses, model building, and diagnostics. Our objective was to establish the best edaphic indicators for assessing soil quality in four no-till systems with regard to functioning as a medium for crop production and nutrient cycling across two Illinois locations. The compared situations were no-till corn-soybean rotations including either winter fallowing (C/S) or cover crops of rye (Secale cereale; C-R/S-R), hairy vetch (Vicia villosa; C-R/S-V), or their mixture (C-R/S-VR). The dataset included the variables bulk density (BD), penetration resistance (PR), water aggregate stability (WAS), soil reaction (pH), and the contents of soil organic matter (SOM), total nitrogen (TN), soil nitrates (NO(3)-N), and available phosphorus (P). Interactive data visualization along with canonical discriminant analysis (CDA) allowed us to show that WAS, BD, and the contents of P, TN, and SOM have the greatest potential as soil quality indicators in no-till systems in Illinois. It was more difficult to discriminate among WCC rotations than to separate these from C/S, considerably inflating the error rate associated with CDA. We predict that observations of no-till C/S will be classified correctly 51% of the time, while observations of no-till WCC rotations will be classified correctly 74% of the time. High error rates in CDA underscore the complexity of no-till systems and the need in this area for more long-term studies with larger datasets to increase accuracy to acceptable levels.

  20. Diversity of entomopathogenic Hypocreales in soil and phylloplanes of five Mediterranean cropping systems.

    PubMed

    Garrido-Jurado, Inmaculada; Fernández-Bravo, María; Campos, Carlos; Quesada-Moraga, Enrique

    2015-09-01

    The diversity of entomopathogenic Hypocreales from the soil and phylloplanes in five Mediterranean cropping systems with different degrees of management [organic olive orchard conventional olive orchard, holm oak reforestation, holm oak dehesa (a multifunctional agro-sylvo-pastoral system), and sunflower plantation] was studied during four seasons. A total of 697 entomopathogenic fungal isolates were obtained from 272 soil samples, 1608 crop phylloplane samples and 1368 weed phylloplane samples. The following nine species were identified: Beauveria amorpha, B. bassiana, B. pseudobassiana, B. varroae, Metarhizium brunneum, M. guizhoense, M. robertsii, Paecilomyces marquandii and lilacinum using EF-1α gene sequences. All the fungal entomopathogenic species were found in both the soil and phylloplane samples, with the exception of M. robertsii, which was only isolated from the soil. The species richness, diversity (Shannon-Wiener index) and evenness (Pielou index) were calculated for each cropping system, yielding the following species ranking, which was correlated with the crop management intensity: holm oak reforestation>organic olive orchard>conventional olive orchard>holm oak dehesa>sunflower plantation. The number of fungal species isolated was similar in both phylloplane habitats and dissimilar between the soil and the crop phylloplane habitats. The ISSR analysis revealed high genotypic diversity among the B. bassiana isolates on the neighbourhood scale, and the isolates were clustered according to the habitat. These results suggest that the entomopathogenic Hypocreales in the phylloplane could result from the dispersal of fungal propagules from the soil, which might be their habitat of origin; a few isolates, including EABb 09/28-Fil of Beauveria bassiana, inhabit only the phylloplane.

  1. Soil carbon sequestration in rainfed production systems in the semiarid tropics of India.

    PubMed

    Srinivasarao, Ch; Lal, Rattan; Kundu, Sumanta; Babu, M B B Prasad; Venkateswarlu, B; Singh, Anil Kumar

    2014-07-15

    Severe soil organic carbon (SOC) depletion is a major constraint in rainfed agroecosystems in India because it directly influences soil quality, crop productivity and sustainability. The magnitude of soil organic, inorganic and total carbon stocks in the semi-arid bioclimate is estimated at 2.9, 1.9 and 4.8 Pg respectively. Sorghum, finger millet, pearl millet, maize, rice, groundnut, soybean, cotton, food legumes etc. are predominant crop production systems with a little, if any, recycling of organic matter. Data from the long term experiments on major rainfed production systems in India show that higher amount of crop residue C input (Mg/ha/y) return back to soil in soybean-safflower (3.37) system practiced in Vertisol region of central India. Long term addition of chemical fertilizer and organic amendments improved the SOC stock. For every Mg/ha increase in SOC stock in the root zone, there occurs an increase in grain yield (kg/ha) of 13, 101, 90, 170, 145, 18 and 160 for groundnut, finger millet, sorghum, pearl millet, soybean and rice, respectively. Long-term cropping without using any organic amendment and/or mineral fertilizers can severely deplete the SOC stock which is the highest in groundnut-finger millet system (0.92 Mg C/ha/y) in Alfisols. Some agroforestry systems also have a huge potential of C sequestration to the extent of 10Mg/ha/y in short rotation eucalyptus and Leucaena plantations. The critical level of C input requirements for maintaining SOC at the antecedent level ranges from 1.1 to 3.5 Mg C/ha/y and differs among soil type and production systems. National level policy interventions needed to promote sustainable use of soil and water resources include prohibiting residue burning, reducing deforestation, promoting integrated farming systems and facilitating payments for ecosystem services. A wide spread adoption of these measures can improve soil quality through increase in SOC sequestration and improvement in agronomic productivity of

  2. Soil Chemical Property Changes in Eggplant/Garlic Relay Intercropping Systems under Continuous Cropping

    PubMed Central

    Wang, Mengyi; Wu, Cuinan; Cheng, Zhihui; Meng, Huanwen; Zhang, Mengru; Zhang, Hongjing

    2014-01-01

    Soil sickness is a critical problem for eggplant (Solanum melongena L.) under continuous cropping that affects sustainable eggplant production. Relay intercropping is a significant technique on promoting soil quality, improving eco-environment, and raising output. Field experiments were conducted from September 2010 to November 2012 in northwest China to determine the effects of relay intercropping eggplant with garlic (Allium sativum L.) on soil enzyme activities, available nutrient contents, and pH value under a plastic tunnel. Three treatments were in triplicate using randomized block design: eggplant monoculture (CK), eggplant relay intercropping with normal garlic (NG) and eggplant relay intercropping with green garlic (GG). The major results are as follows: (1) the activities of soil invertase, urease, and alkaline phosphatase were generally enhanced in NG and GG treatments; (2) relay intercropping significantly increased the soil available nutrient contents, and they were mostly higher in GG than NG. On April 11, 2011, the eggplant/garlic co-growth stage, the available nitrogen content in GG was 76.30 mg·kg−1, significantly higher than 61.95 mg·kg−1 in NG. For available potassium on April 17, 2012, they were 398.48 and 387.97 mg·kg−1 in NG and GG, both were significantly higher than 314.84 mg·kg−1 in CK; (3) the soil pH showed a significantly higher level in NG treatment, but lower in GG treatment compared with CK. For the last samples in 2012, soil pH in NG and GG were 7.70 and 7.46, the highest and lowest one among them; (4) the alkaline phosphatase activity and pH displayed a similar decreasing trend with continuous cropping. These findings indicate that relay intercropping eggplant with garlic could be an ideal farming system to effectively improve soil nutrient content, increase soil fertility, and alleviate soil sickness to some extent. These findings are important in helping to develop sustainable eggplant production. PMID:25340875

  3. Soil chemical property changes in eggplant/garlic relay intercropping systems under continuous cropping.

    PubMed

    Wang, Mengyi; Wu, Cuinan; Cheng, Zhihui; Meng, Huanwen; Zhang, Mengru; Zhang, Hongjing

    2014-01-01

    Soil sickness is a critical problem for eggplant (Solanum melongena L.) under continuous cropping that affects sustainable eggplant production. Relay intercropping is a significant technique on promoting soil quality, improving eco-environment, and raising output. Field experiments were conducted from September 2010 to November 2012 in northwest China to determine the effects of relay intercropping eggplant with garlic (Allium sativum L.) on soil enzyme activities, available nutrient contents, and pH value under a plastic tunnel. Three treatments were in triplicate using randomized block design: eggplant monoculture (CK), eggplant relay intercropping with normal garlic (NG) and eggplant relay intercropping with green garlic (GG). The major results are as follows: (1) the activities of soil invertase, urease, and alkaline phosphatase were generally enhanced in NG and GG treatments; (2) relay intercropping significantly increased the soil available nutrient contents, and they were mostly higher in GG than NG. On April 11, 2011, the eggplant/garlic co-growth stage, the available nitrogen content in GG was 76.30 mg·kg(-1), significantly higher than 61.95 mg·kg(-1) in NG. For available potassium on April 17, 2012, they were 398.48 and 387.97 mg·kg(-1) in NG and GG, both were significantly higher than 314.84 mg·kg(-1) in CK; (3) the soil pH showed a significantly higher level in NG treatment, but lower in GG treatment compared with CK. For the last samples in 2012, soil pH in NG and GG were 7.70 and 7.46, the highest and lowest one among them; (4) the alkaline phosphatase activity and pH displayed a similar decreasing trend with continuous cropping. These findings indicate that relay intercropping eggplant with garlic could be an ideal farming system to effectively improve soil nutrient content, increase soil fertility, and alleviate soil sickness to some extent. These findings are important in helping to develop sustainable eggplant production. PMID:25340875

  4. Soil chemical property changes in eggplant/garlic relay intercropping systems under continuous cropping.

    PubMed

    Wang, Mengyi; Wu, Cuinan; Cheng, Zhihui; Meng, Huanwen; Zhang, Mengru; Zhang, Hongjing

    2014-01-01

    Soil sickness is a critical problem for eggplant (Solanum melongena L.) under continuous cropping that affects sustainable eggplant production. Relay intercropping is a significant technique on promoting soil quality, improving eco-environment, and raising output. Field experiments were conducted from September 2010 to November 2012 in northwest China to determine the effects of relay intercropping eggplant with garlic (Allium sativum L.) on soil enzyme activities, available nutrient contents, and pH value under a plastic tunnel. Three treatments were in triplicate using randomized block design: eggplant monoculture (CK), eggplant relay intercropping with normal garlic (NG) and eggplant relay intercropping with green garlic (GG). The major results are as follows: (1) the activities of soil invertase, urease, and alkaline phosphatase were generally enhanced in NG and GG treatments; (2) relay intercropping significantly increased the soil available nutrient contents, and they were mostly higher in GG than NG. On April 11, 2011, the eggplant/garlic co-growth stage, the available nitrogen content in GG was 76.30 mg·kg(-1), significantly higher than 61.95 mg·kg(-1) in NG. For available potassium on April 17, 2012, they were 398.48 and 387.97 mg·kg(-1) in NG and GG, both were significantly higher than 314.84 mg·kg(-1) in CK; (3) the soil pH showed a significantly higher level in NG treatment, but lower in GG treatment compared with CK. For the last samples in 2012, soil pH in NG and GG were 7.70 and 7.46, the highest and lowest one among them; (4) the alkaline phosphatase activity and pH displayed a similar decreasing trend with continuous cropping. These findings indicate that relay intercropping eggplant with garlic could be an ideal farming system to effectively improve soil nutrient content, increase soil fertility, and alleviate soil sickness to some extent. These findings are important in helping to develop sustainable eggplant production.

  5. Treatment of TNT contaminated soil and groundwater using plant-based enzyme systems

    SciTech Connect

    Medina, V.F.; Wolfe, L.; McCutcheon, S.C.

    1995-12-31

    Trinitrotoluene (TNT) is considered toxic and a mutagen. For over 100 years, TNT has been widely used in explosives for both military and commercial applications. Soil and groundwater contamination by TNT is prevalent at military bases, manufacturing facilities and at commercial (such as mining) sites were TNT was used or stored. TNT is a difficult compound to treat. It is resistant to complete microbial degradation. Although incineration is feasible, it can be costly. One promising technology is degradation using plant enzyme systems, which has become known as phytoremediation. This paper will highlight bench and field studies of phytoremediation of TNT contaminated soil and groundwater. Parameters for developing a model will be discussed.

  6. Optimizing root system architecture in biofuel crops for sustainable energy production and soil carbon sequestration.

    PubMed

    To, Jennifer Pc; Zhu, Jinming; Benfey, Philip N; Elich, Tedd

    2010-01-01

    Root system architecture (RSA) describes the dynamic spatial configuration of different types and ages of roots in a plant, which allows adaptation to different environments. Modifications in RSA enhance agronomic traits in crops and have been implicated in soil organic carbon content. Together, these fundamental properties of RSA contribute to the net carbon balance and overall sustainability of biofuels. In this article, we will review recent data supporting carbon sequestration by biofuel crops, highlight current progress in studying RSA, and discuss future opportunities for optimizing RSA for biofuel production and soil carbon sequestration.

  7. Optimizing root system architecture in biofuel crops for sustainable energy production and soil carbon sequestration

    PubMed Central

    To, Jennifer PC; Zhu, Jinming; Benfey, Philip N

    2010-01-01

    Root system architecture (RSA) describes the dynamic spatial configuration of different types and ages of roots in a plant, which allows adaptation to different environments. Modifications in RSA enhance agronomic traits in crops and have been implicated in soil organic carbon content. Together, these fundamental properties of RSA contribute to the net carbon balance and overall sustainability of biofuels. In this article, we will review recent data supporting carbon sequestration by biofuel crops, highlight current progress in studying RSA, and discuss future opportunities for optimizing RSA for biofuel production and soil carbon sequestration. PMID:21173868

  8. Speciation study in the sulfamethoxazole-copper-pH-soil system: implications for retention prediction.

    PubMed

    Morel, Marie-Christine; Spadini, Lorenzo; Brimo, Khaled; Martins, Jean M F

    2014-05-15

    Sulfamethoxazole (SMX) is a persistent sulfonamide antibiotic drug used in the veterinary and human medical sectors and is widely detected in natural waters. To better understand the reactive transport of this antibiotic in soil, the speciation of the SMX-Cu(II)-H(+) system in solution and the combined sorption of these components in a natural vineyard soil were investigated by acid-base titrimetry and infrared spectroscopy. Cu(II) is considered to represent a strongly complexing trace element cation (such as Cd(2+), Zn(2+), Pb(2+), Ni(2+), etc.) in comparison to more prevalent but more weakly binding cations (such as Ca(2+) and Mg(2+)). Titrimetric studies showed that, relative to other antibiotics, such as tetracycline, SMX is a weak copper chelating agent and a weak soil sorbent at the soil pH (pH6). However, the sorption of SMX in soil increases strongly (by a factor of 6) in the presence of copper. This finding strongly supports the hypothetical formation of ternary SMX-Cu-soil complexes, especially considering that copper is dominantly sorbed in a state at pH6. The data were successfully modelled with PhreeqC assuming the existence of binary and ternary surface complexes in equilibrium with aqueous Cu, SMX and Cu-SMX complexes. It is thought that other strongly complexing cations present on the surface of reactive organic and mineral soil phases, such as Cd(II), Ni(II), Zn(II), Pb(II), Fe(II/III), Mn(II/IV) and Al(III), affect the solid/solution partitioning of SMX. This study thus suggests that surface-adsorbed cations significantly increase the sorption of SMX.

  9. Construction of disturbed and intact soil blocks to develop percolating soil based treatment systems for dirty water from dairy farms.

    PubMed

    Brookman, S K E; Chadwick, D R; Headon, D M

    2002-03-01

    Intact soil blocks with a surface area of 1.8 x 1.6 m, 1.0 m deep, were excavated in a coarse sandy loam. The sides of the soil blocks were supported with plywood before using hydraulic rams to force a steel cutting plate beneath them. Disturbed soil blocks of the same depth as the intact blocks were also established. Experiments were conducted to determine purification efficiencies for biological oxygen demand (BOD), molybdate reactive phosphorus (MRP), nitrate and ammonium-N after the application of dirty water. A preliminary experiment is described where a low application of dirty water was applied to the soil blocks, 2 mm day(-1). In addition, a chloride tracer was conducted for the duration of the experiment. Disturbed soil had a purification efficiency for BOD of 99% compared to 96% from intact soil (P<0.001). Purification efficiencies for MRP and ammonium-N were 100 and 99%, respectively, for the intact and disturbed soils. Nitrate-N concentration increased in leachate from both treatments reaching maximum concentrations of 15 and 8 mg l(-1) from disturbed and intact soils, respectively. Chloride traces for each soil block followed similar patterns with 47 and 51% loss from disturbed and intact soils, respectively.

  10. Bioremediation of 2,4,6-trinitrotoluene-contaminated soils by two different aerated compost systems.

    PubMed

    Breitung, J; Bruns-Nagel, D; Steinbach, K; Kaminski, L; Gemsa, D; von Löw, E

    1996-02-01

    Two composting systems were compared on a laboratory scale as a bioremediation technology for degradation or immobilization of 2,4,6-trinitrotoluene (TNT) in contaminated soils. The first compost was aerated from the beginning whereas the second compost was only aerated after an anaerobic prephase of 65 days. In the first compost system the TNT concentration declined rapidly by 92% but, at the end, TNT could be partially recovered. During the anaerobic prephase of the second compost system, TNT was almost completely converted to aminodinitrotoluenes, which during the subsequent aeration almost entirely disappeared. In addition, the second compost generated less toxic material than the first one as confirmed by inhibition of bioluminescence of Vibrio fischeri. These data show that microbiological TNT-degradation systems can be successfully designed which are prerequisite for an efficient bioremediation of contaminated soils.

  11. A new TDR multiplexing system for reliable electrical conductivity and soil water content measurements

    NASA Astrophysics Data System (ADS)

    Weihermueller, Lutz; Huisman, Sander; Hermes, Normen; Pickel, Stefanie; Vereecken, Harry

    2013-04-01

    Time domain reflectometry (TDR) is a standard method to estimate soil water content and bulk soil electrical conductivity. In many applications, several TDR probes are installed in soil columns or field setups, and they are measured using a multiplexing system. It has been reported that commercially available multiplexers share a common ground, which might lead to inaccurate TDR measurements when probes are installed close together or at sites with high electromagnetic noise. Therefore, a new eight-channel differential multiplexer (50C81-SDM) was developed that allows communication with standard TDR equipment. The 50C81-SDM multiplexer was tested using measurement in electrolyte solutions and a sand tank. In contrast to multiplexers with a common ground, they showed no interference of closely spaced TDR probes. Measurements at a test site also showed the applicability of the 50C81-SDM multiplexer in an environment contaminated with high electromagnetic noise.

  12. Determination of microelement distribution in different components of soil-plant systems

    NASA Astrophysics Data System (ADS)

    Hung, Luu Viet; Maslov, O. D.; Gustova, M. V.; My, Trinh Thi Thu; Ho, Phung Khac Nam

    2011-07-01

    The leaves, stem, and roots of two types of shrubs (tea ( Camellia sinensis) and sweet leaf ( Sauropus androgynus)) and two types of herbs (vetiver grass ( Vetiveria zizanioides L. Nash) and maize ( Zea mays L)) and the Thucuc soil where the plants were growing were collected to be studied. The contents of 22 elements in the samples were determined by three methods: X-Ray fluorescence analysis (XRFA), gamma activation analysis (GAA), and the tracking method to study the distribution of these elements in plants and the soil-plant relationship. This study was carried out at the Flerov Laboratory of Nuclear Reactions (FLNR), Joint Institute for Nuclear Research (JINR), Dubna, Russia. The distribution of the elements in the soil-plant system was studied.

  13. Seasonal Soil Nitrogen Mineralization within an Integrated Crop and Livestock System in Western North Dakota, USA

    NASA Astrophysics Data System (ADS)

    Landblom, Douglas; Senturklu, Songul; Cihacek, Larry; Pfenning, Lauren; Brevik, Eric C.

    2015-04-01

    Protecting natural resources while maintaining or maximizing crop yield potential is of utmost importance for sustainable crop and livestock production systems. Since soil organic matter and its decomposition by soil organisms is at the very foundation of healthy productive soils, systems research at the North Dakota State University Dickinson Research Extension Center is evaluating seasonal soil nitrogen fertility within an integrated crop and livestock production system. The 5-year diverse crop rotation is: sunflower (SF) - hard red spring wheat (HRSW) - fall seeded winter triticale-hairy vetch (THV; spring harvested for hay)/spring seeded 7-species cover crop (CC) - Corn (C) (85-90 day var.) - field pea-barley intercrop (PBY). The HRSW and SF are harvested as cash crops and the PBY, C, and CC are harvested by grazing cattle. In the system, yearling beef steers graze the PBY and C before feedlot entry and after weaning, gestating beef cows graze the CC. Since rotation establishment, four crop years have been harvested from the crop rotation. All crops have been seeded using a JD 1590 no-till drill except C and SF. Corn and SF were planted using a JD 7000 no-till planter. The HRSW, PBY, and CC were seeded at a soil depth of 3.8 cm and a row width of 19.1 cm. Seed placement for the C and SF crops was at a soil depth of 5.1 cm and the row spacing was 0.762 m. The plant population goal/ha for C, SF, and wheat was 7,689, 50,587, and 7,244 p/ha, respectively. During the 3rd cropping year, soil bulk density was measured and during the 4th cropping year, seasonal nitrogen fertility was monitored throughout the growing season from June to October. Seasonal nitrate nitrogen (NO3-N), ammonium nitrogen (NH4-N), total season mineral nitrogen (NO3-N + NH4-N), cropping system NO3-N, and bulk density were measured in 3 replicated non-fertilized field plot areas within each 10.6 ha triple replicated crop fields. Within each plot area, 6 - 20.3 cm x 0.61 m aluminum irrigation

  14. Cropping systems and control of soil erosion in a Mediterranean environment

    NASA Astrophysics Data System (ADS)

    Cosentino, Salvatore; Copani, Venera; Testa, Giorgio; Scalici, Giovanni

    2013-04-01

    The research has been carried out over the years 1996-2010 in an area of the internal hill of Sicily region (Enna, c.da Geracello, 550 m a. s. l. 37° 23' N. Lat, 14° 21' E. Long) in the center of Mediterranean Sea, mainly devoted to durum wheat cultivation, using the experimental plots, established in 1996 on a slope of 26-28%, equipped to determine surface runoff and soil losses. The establishment consists of twelve plots, having 40 m length and 8 m width. In order to study the effect of different field crop systems in controlling soil erosion in slopes subjected to water erosion, the following systems were studied: permanent crops, tilled annual crops, no-tilled annual crops, set-aside. The used crops were: durum wheat, faba bean, rapeseed, subterranean clover, Italian ryegrass, alfalfa, sweetvetch, moon trefoil, barley, sweet sorghum, sunflower. The results pointed out that the cropping systems with perennial crops allowed to keep low the soil loss, while annual crop rotation determined a high amount of soil loss. Sod seeding showed promising results also for annual crop rotations.

  15. Some Sensitivity Studies of Chemical Transport Simulated in Models of the Soil-Plant-Litter System

    SciTech Connect

    Begovich, C.L.

    2002-10-28

    Fifteen parameters in a set of five coupled models describing carbon, water, and chemical dynamics in the soil-plant-litter system were varied in a sensitivity analysis of model response. Results are presented for chemical distribution in the components of soil, plants, and litter along with selected responses of biomass, internal chemical transport (xylem and phloem pathways), and chemical uptake. Response and sensitivity coefficients are presented for up to 102 model outputs in an appendix. Two soil properties (chemical distribution coefficient and chemical solubility) and three plant properties (leaf chemical permeability, cuticle thickness, and root chemical conductivity) had the greatest influence on chemical transport in the soil-plant-litter system under the conditions examined. Pollutant gas uptake (SO{sub 2}) increased with change in plant properties that increased plant growth. Heavy metal dynamics in litter responded to plant properties (phloem resistance, respiration characteristics) which induced changes in the chemical cycling to the litter system. Some of the SO{sub 2} and heavy metal responses were not expected but became apparent through the modeling analysis.

  16. Strong linkage between plant and soil fungal communities along a successional coastal dune system.

    PubMed

    Roy-Bolduc, Alice; Laliberté, Etienne; Boudreau, Stéphane; Hijri, Mohamed

    2016-10-01

    Complex interactions between plants and soil microorganisms drive key ecosystem and community properties such as productivity and diversity. In nutrient-poor systems such as sand dunes, plant traits and fungal symbioses related to nutrient acquisition can strongly influence vegetation dynamics. We investigated plant and fungal communities in a relic foredune plain located on an archipelago in Québec, Canada. We detected distinct communities across the edaphic and successional gradient. Our results showed a clear increase in plant species richness, as well as in the diversity of nutrient-acquisition strategies. We also found a strong correlation between aboveground vegetation and soil fungal communities, and both responded similarly to soil physicochemical properties. Soil pH influenced the composition of plant and fungal communities, and could act as an important environmental filter along this relic foredune plain. The increasing functional diversity in plant nutrient-acquisition strategies across the gradient might favor resource partitioning and facilitation among co-occurring plant species. The coordinated changes in soil microbial and plant communities highlight the importance of aboveground-belowground linkages and positive biotic interactions during ecological succession in nutrient-poor environments.

  17. Phosphorus depletion in forest soils shapes bacterial communities towards phosphorus recycling systems.

    PubMed

    Bergkemper, Fabian; Schöler, Anne; Engel, Marion; Lang, Friederike; Krüger, Jaane; Schloter, Michael; Schulz, Stefanie

    2016-06-01

    Phosphorus (P) is an important macronutrient for all biota on earth but similarly a finite resource. Microorganisms play on both sides of the fence as they effectively mineralize organic and solubilize precipitated forms of soil phosphorus but conversely also take up and immobilize P. Therefore, we analysed the role of microbes in two beech forest soils with high and low P content by direct sequencing of metagenomic deoxyribonucleic acid. For inorganic P solubilization, a significantly higher microbial potential was detected in the P-rich soil. This trait especially referred to Candidatus Solibacter usiatus, likewise one of the dominating species in the data sets. A higher microbial potential for efficient phosphate uptake systems (pstSCAB) was detected in the P-depleted soil. Genes involved in P starvation response regulation (phoB, phoR) were prevalent in both soils. This underlines the importance of effective phosphate (Pho) regulon control for microorganisms to use alternative P sources during phosphate limitation. Predicted genes were primarily harboured by Rhizobiales, Actinomycetales and Acidobacteriales. PMID:26690731

  18. Experimental investigation on feasible bioreactor using mechanism of hydrogen oxidation of natural soil for detritiation system.

    PubMed

    Edao, Yuki; Iwai, Yasunori; Sato, Katsumi; Hayashi, Takumi

    2016-08-01

    A passive reactor for tritium oxidation at room temperature has been widely studied in nuclear engineering especially for a detritiation system (DS) of a tritium process facility taking possible extraordinary situation severely into consideration. We have focused on bacterial oxidation of tritium by hydrogen-oxidizing bacteria in natural soil to realize the passive oxidation reactor. The purpose of this study was to examine the feasibility of a bioreactor with hydrogen-oxidizing bacteria in soil from a point of view of engineering. The efficiency of the bioreactor was evaluated by kinetics. The bioreactor packed with natural soil shows a relative high conversion rate of tritium under the saturated moisture condition at room temperature, which is obviously superior to that of a Pt/Al2O3 catalyst generally used for tritium oxidation in the existing tritium handling facilities. The order of reaction for tritium oxidation with soil was the pseudo-first order as assessed with Michaelis-Menten kinetics model. Our engineering suggestion to increase the reaction rate is the intentional addition of hydrogen at a small concentration in the feed gas on condition that the oxidation of tritium with soil is expressed by the Michaelis-Menten kinetics model.

  19. Strong linkage between plant and soil fungal communities along a successional coastal dune system.

    PubMed

    Roy-Bolduc, Alice; Laliberté, Etienne; Boudreau, Stéphane; Hijri, Mohamed

    2016-10-01

    Complex interactions between plants and soil microorganisms drive key ecosystem and community properties such as productivity and diversity. In nutrient-poor systems such as sand dunes, plant traits and fungal symbioses related to nutrient acquisition can strongly influence vegetation dynamics. We investigated plant and fungal communities in a relic foredune plain located on an archipelago in Québec, Canada. We detected distinct communities across the edaphic and successional gradient. Our results showed a clear increase in plant species richness, as well as in the diversity of nutrient-acquisition strategies. We also found a strong correlation between aboveground vegetation and soil fungal communities, and both responded similarly to soil physicochemical properties. Soil pH influenced the composition of plant and fungal communities, and could act as an important environmental filter along this relic foredune plain. The increasing functional diversity in plant nutrient-acquisition strategies across the gradient might favor resource partitioning and facilitation among co-occurring plant species. The coordinated changes in soil microbial and plant communities highlight the importance of aboveground-belowground linkages and positive biotic interactions during ecological succession in nutrient-poor environments. PMID:27411980

  20. Cadmium transfer and detoxification mechanisms in a soil-mulberry-silkworm system: phytoremediation potential.

    PubMed

    Zhou, Lingyun; Zhao, Ye; Wang, Shuifeng

    2015-11-01

    Phytoremediation has been proven to be an environmentally sound alternative for the recovery of contaminated soils, and the economic profit that comes along with the process might stimulate its field use. This study investigated cadmium (Cd) transfer and detoxification mechanisms in a soil-mulberry-silkworm system to estimate the suitability of the mulberry and silkworm as an alternative method for the remediation of Cd-polluted soil; it also explored the underlying mechanisms regulating the trophic transfer of Cd. The results show that both the mulberry and silkworm have high Cd tolerance. The transfer factor suggests that the mulberry has high potential for Cd extraction from polluted soil. The subcellular distribution and chemical forms of Cd in mulberry leaves show that cell wall deposition and vacuolar compartmentalization play important role in Cd tolerance. In the presence of increasing Cd concentrations in silkworm food, detoxification mechanisms (excretion and homeostasis) were activated so that excess Cd was excreted in fecal balls, and metallothionein levels in the mid-gut, the posterior of the silk gland, and the fat body of silkworms were enhanced. And, the Cd concentrations in silk are at a low level, ranging from 0.02 to 0.21 mg kg(-1). Therefore, these mechanisms of detoxification can regulate Cd trophic transfer, and mulberry planting and silkworm breeding has high phytoremediation potential for Cd-contaminated soil.

  1. Soil Decomposition of Added Organic C in an Organic Farming System

    NASA Astrophysics Data System (ADS)

    Kpomblekou-A, Kokoasse; Sissoko, Alassane; McElhenney, Wendell

    2015-04-01

    In the United States, large quantities of poultry waste are added every year to soil under organic management. Decomposition of the added organic C releases plant nutrients, promotes soil structure, and plays a vital role in the soil food web. In organic agriculture the added C serves as the only source of nutrients for plant growth. Thus understanding the decomposition rates of such C in organic farming systems are critical in making recommendations of organic inputs to organic producers. We investigated and compared relative accumulation and decomposition of organic C in an organic farming system trial at the George Washington Carver Agricultural Experiment Station at Tuskegee, Alabama on a Marvyn sandy loam (fine-loamy, kaolinitic, thermic, Typic Kanhapludults) soil. The experimental design was a randomized complete block with four replicates and four treatments. The main plot (54' × 20') was split into three equal subplots to plant three sweet potato cultivars. The treatments included a weed (control with no cover crop, no fertilizer), crimson clover alone (CC), crimson clover plus broiler litter (BL), and crimson clover plus NPK mineral fertilizers (NPK). For five years, late in fall, the field was planted with crimson clover (Trifolium incarnatum L) that was cut with a mower and incorporated into soil the following spring. Moreover, broiler litter (4.65 Mg ha-1) or ammonium nitrate (150 kg N ha-1), triple super phosphate (120 kg P2O5 ha-1), and potassium chloride (160 kg K2O ha-1) were applied to the BL or the NPK plot and planted with sweet potato. Just before harvest, six soil samples were collected within the two middle rows of each sweet potato plot with an auger at incremental depths of 0-1, 1-2, 2-3, 3-5, 5-10, and 10-15 cm. Samples from each subplot and depth were composited and mixed in a plastic bag. The samples were sieved moist through a

  2. Assessing nutrient losses with soil erosion under different tillage systems and their implications on water quality

    NASA Astrophysics Data System (ADS)

    Munodawafa, Adelaide

    An increased public perception of the role of agriculture in non-point source pollution has stimulated the need for information on the effect of conventional and sustainable agricultural management systems on water quality. While information on run-off and soil erosion is readily available in Zimbabwe, there is dearth of knowledge on the relative losses of nutrients as a result of soil erosion and their effect on water quality. This study sought to quantify the amount of nutrients lost as a result of soil erosion and thus enable conclusions to be drawn on the implications on water quality. Research work was carried out in the semi-arid region of Zimbabwe under granite-derived, inherently infertile sandy soils. Soil erosion was quantified under three tillage systems conventional tillage (CT); mulch ripping (MR); tied ridging (TR) over three years. Run-off and sediments were analysed for N, P and K. The results showed that N and K losses were significantly higher ( p < 0.001) under CT (15.8 and 34.5 kg ha -1 yr -1, respectively) compared to the MR (2.3 and 0.6 kg ha -1 yr -1, respectively) and TR (2.7 and 4.3 kg ha -1 yr -1, respectively). Due to the immobility of P and its small quantities in these soils, P losses were also low across all treatments (<1 kg ha -1 yr -1), however CT had significantly higher losses ( p < 0.001). The study showed that CT results in high losses of nutrients, which would in turn reduce the quality of surface waters, due to high nutrient concentrations of especially, N, which stimulates the growth of algae and other aquatic weeds. The gravity of the situation would be higher, where soils are more fertile. MR and TR were efficient in reducing soil erosion and thus nutrient losses with run-off and sediments. Pollution of surface water sources can be greatly reduced if conservation tillage systems are used.

  3. GeoSurf - geoelectric soil modelling for a sustainable land use and efficient planning of shallow geothermal systems

    NASA Astrophysics Data System (ADS)

    Bertermann, David; Walker-Hertkorn, Simone; Kübert, Markus; Schmidt, David; Di Sipio, Eloisa; Müller, Johannes; Schwarz, Hans

    2016-04-01

    Due to the increased demand of biomaterials and renewable primary products the world's soil is intensively effected. Land usage needs to be efficient, space-saving and sustainable. To fulfil these needs soil properties have to be analysed and mapped. Furthermore the shortage of resources will boost the role of renewable energy sources within all energy supplying systems. Also for very shallow geothermal systems (e.g. collectors or heat baskets) detailed information of soil properties are necessary. The most important parameters for characterisation of the soil body are grain size distribution, bulk density and moisture content. Within this project geoelectric measurements more than 50 m wide and 20 m deep cross-sections were made. The above-named soil properties and the thermal conductivity were determined as well. The soil parameters were analysed regarding their effects on thermal- and electric conductivity. With the results of these geoelectric cross-sections in comparison with the measured soil texture, reliable statements about the existing soil properties and a deduction of its thermal conductivity can be made. Within the uppermost meters of the ground, thermal conductivity is mainly driven by soil type. So reasonable recommendations of soil properties and its thermal conductivity are possible only by measuring the electrical conductivity. With these measurements also clear and demonstrative soil models can be illustrated. The electrical conductivity provides expedient information about the soil that opens up the opportunity for clear recommendations about sustainable land use and for site-specific installation of very shallow geothermal system. Also predictions for other soil controlled investigations are possible.

  4. Investigation of the degradation of 13C-labeled fungal biomass in soil - fate of carbon in a soil bioreactor system

    NASA Astrophysics Data System (ADS)

    Schweigert, Michael; Fester, Thomas; Miltner, Anja; Kaestner, Matthias

    2015-04-01

    Nutrient balances and degradation processes in boreal forests are mainly influenced by interactions of plant roots and ectomycorrhizal fungi. Plants benefit from nitrogen compounds provided by their symbiotic interaction partner. In return ectomycorrhiza are provided by large amounts of carbon from the plants which is used for the synthesis of hyphal networks in soil and for metabolic activity for nutrient uptake. Therefore, ectomycorrhizal fungi play a major role in ecosystems of boreal forests and are consequently an important sink for carbon by building large amount of mycelia. Recently, it has been shown that microbial biomass residues contribute significantly to soil organic matter formation. This suggests that also residues of ectomycorrhizal fungi may be an important source for soil organic matter formation in forest soils where these fungi are abundant. However, the fate of ectomycorrhizal biomass residues in soils is unknown. We therefore investigated the fate of ectomycorrhizal biomass in soil in a soil bioreactor system to quantify the contribution of this material to soil organic matter formation. As a model organism, we selected Laccaria bicolor, which was labelled by growing the fungus on 13C glucose. The stable isotope-labeled biomass was then homogenized and incubated in a podzol from a typical forest site in Central Germany. The fate of the labeled biomass was traced by analyzing the amount of 13C mineralized and the amount remaining in the soil. The fungal biomass carbon was mineralized rather rapidly during the first 50 days. Then the mineralization rate slowed down, but mineralization continued until the end of the experiment, when approximately 40% of the 13C was mineralized and 60% remained in soil. In addition, we analyzed biomolecules such as fatty acids to trace the incorporation of the L. bicolor-derived biomass carbon into other microorganisms and to identify potential primary consumers of fungal biomass. By these analyses, we found a

  5. Dryland soil hydrological processes and their impacts on the nitrogen balance in a soil-maize system of a freeze-thawing agricultural area.

    PubMed

    Ouyang, Wei; Chen, Siyang; Cai, Guanqing; Hao, Fanghua

    2014-01-01

    Understanding the fates of soil hydrological processes and nitrogen (N) is essential for optimizing the water and N in a dryland crop system with the goal of obtaining a maximum yield. Few investigations have addressed the dynamics of dryland N and its association with the soil hydrological process in a freeze-thawing agricultural area. With the daily monitoring of soil water content and acquisition rates at 15, 30, 60 and 90 cm depths, the soil hydrological process with the influence of rainfall was identified. The temporal-vertical soil water storage analysis indicated the local albic soil texture provided a stable soil water condition for maize growth with the rainfall as the only water source. Soil storage water averages at 0-20, 20-40 and 40-60 cm were observed to be 490.2, 593.8, and 358 m3 ha-1, respectively, during the growing season. The evapo-transpiration (ET), rainfall, and water loss analysis demonstrated that these factors increased in same temporal pattern and provided necessary water conditions for maize growth in a short period. The dry weight and N concentration of maize organs (root, leaf, stem, tassel, and grain) demonstrated the N accumulation increased to a peak in the maturity period and that grain had the most N. The maximum N accumulative rate reached about 500 mg m-2d-1 in leaves and grain. Over the entire growing season, the soil nitrate N decreased by amounts ranging from 48.9 kg N ha-1 to 65.3 kg N ha-1 over the 90 cm profile and the loss of ammonia-N ranged from 9.79 to 12.69 kg N ha-1. With soil water loss and N balance calculation, the N usage efficiency (NUE) over the 0-90 cm soil profile was 43%. The soil hydrological process due to special soil texture and the temporal features of rainfall determined the maize growth in the freeze-thawing agricultural area.

  6. Dryland Soil Hydrological Processes and Their Impacts on the Nitrogen Balance in a Soil-Maize System of a Freeze-Thawing Agricultural Area

    PubMed Central

    Ouyang, Wei; Chen, Siyang; Cai, Guanqing; Hao, Fanghua

    2014-01-01

    Understanding the fates of soil hydrological processes and nitrogen (N) is essential for optimizing the water and N in a dryland crop system with the goal of obtaining a maximum yield. Few investigations have addressed the dynamics of dryland N and its association with the soil hydrological process in a freeze-thawing agricultural area. With the daily monitoring of soil water content and acquisition rates at 15, 30, 60 and 90 cm depths, the soil hydrological process with the influence of rainfall was identified. The temporal-vertical soil water storage analysis indicated the local albic soil texture provided a stable soil water condition for maize growth with the rainfall as the only water source. Soil storage water averages at 0–20, 20–40 and 40–60 cm were observed to be 490.2, 593.8, and 358 m3 ha−1, respectively, during the growing season. The evapo-transpiration (ET), rainfall, and water loss analysis demonstrated that these factors increased in same temporal pattern and provided necessary water conditions for maize growth in a short period. The dry weight and N concentration of maize organs (root, leaf, stem, tassel, and grain) demonstrated the N accumulation increased to a peak in the maturity period and that grain had the most N. The maximum N accumulative rate reached about 500 mg m−2d−1 in leaves and grain. Over the entire growing season, the soil nitrate N decreased by amounts ranging from 48.9 kg N ha−1 to 65.3 kg N ha−1 over the 90 cm profile and the loss of ammonia-N ranged from 9.79 to 12.69 kg N ha−1. With soil water loss and N balance calculation, the N usage efficiency (NUE) over the 0–90 cm soil profile was 43%. The soil hydrological process due to special soil texture and the temporal features of rainfall determined the maize growth in the freeze-thawing agricultural area. PMID:25000400

  7. The Role of Vegetation and Mulch in Mitigating the Impact of Raindrops on Soils in Urban Vegetated Green Infrastructure Systems

    NASA Astrophysics Data System (ADS)

    Alizadehtazi, B.; Montalto, F. A.; Sjoblom, K.

    2014-12-01

    Raindrop impulses applied to soils can break up larger soil aggregates into smaller particles, dispersing them from their original position. The displaced particles can self-stratify, with finer particles at the top forming a crust. Occurrence of this phenomenon reduces the infiltration rate and increases runoff, contributing to downstream flooding, soil erosion, and non point source pollutant loads. Unprotected soil surfaces (e.g. without vegetation canopies, mulch, or other materials), are more susceptible to crust formation due to the higher kinetic energy associated with raindrop impact. By contrast, soil that is protected by vegetation canopies and mulch layers is less susceptible to crust formation, since these surfaces intercept raindrops, dissipating some of their kinetic energy prior to their impact with the soil. Within this context, this presentation presents preliminary laboratory work conducted using a rainfall simulator to determine the ability of new urban vegetation and mulch to minimize soil crust formation. Three different scenarios are compared: a) bare soil, b) soil with mulch cover, and c) soil protected by vegetation canopies. Soil moisture, surface penetration resistance, and physical measurements of the volume of infiltrate and runoff are made on all three surface treatments after simulated rainfall events. The results are used to develop recommendations regarding surface treatment in green infrastructure (GI) system designs, namely whether heavily vegetated GI facilities require mulching to maintain infiltration capacity.

  8. Substrate and environmental controls on microbial assimilation of soil organic carbon: a framework for Earth system models.

    PubMed

    Xu, Xiaofeng; Schimel, Joshua P; Thornton, Peter E; Song, Xia; Yuan, Fengming; Goswami, Santonu

    2014-05-01

    A mechanistic understanding of microbial assimilation of soil organic carbon is important to improve Earth system models' ability to simulate carbon-climate feedbacks. A simple modelling framework was developed to investigate how substrate quality and environmental controls over microbial activity regulate microbial assimilation of soil organic carbon and on the size of the microbial biomass. Substrate quality has a positive effect on microbial assimilation of soil organic carbon: higher substrate quality leads to higher ratio of microbial carbon to soil organic carbon. Microbial biomass carbon peaks and then declines as cumulative activity increases. The simulated ratios of soil microbial biomass to soil organic carbon are reasonably consistent with a recently compiled global data set at the biome level. The modelling framework developed in this study offers a simple approach to incorporate microbial contributions to the carbon cycling into Earth system models to simulate carbon-climate feedbacks and explain global patterns of microbial biomass.

  9. Soil, Water, and Greenhouse-gas Impacts of Alternative Biomass Cropping Systems

    NASA Astrophysics Data System (ADS)

    Schulte Moore, L. A.; Bach, E.; Cambardella, C.; Hargreaves, S.; Helmers, M.; Hofmockel, K.; Isenhart, T.; Kolka, R. K.; Ontl, T.; Welsh, W.; Williams, R.; Landscape Biomass Team

    2010-12-01

    Through the 2008 Energy Independence and Security Act and other state and federal mandates, the U.S. is embarking on an aggressive agenda to reduce dependency on fossil fuels. While grain-derived ethanol will be used to largely meet initial renewable fuels targets, advanced biofuels derived from lignocellulosic materials are expected to comprise a growing proportion of the renewable energy portfolio and provide a more sustainable solution. As part of our interdisciplinary research, we are assessing the environmental impacts of four lignocellulosic biomass cropping systems and comparing them to a conventional corn cropping system. This comparison is conducted using a randomized, replicated experiment initiated in fall 2008, which compares the five cropping systems across a toposequence (i.e., floodplain, toeslope, backslope, shoulder, summit). In addition to assessing herbaceous and woody biomass yields, we are evaluating the environmental performance of these systems through changes in water quality, greenhouse-gas emissions, and carbon pools. Initial results document baseline soil parameters, including the capacity of the soils to sequester carbon across the toposequence, and the impacts of landscape heterogeneity and cropping system on soil moisture and nitrate-nitrogen levels in the vadose zone. Additional results on greenhouse-gas emissions and carbon dynamics are forthcoming from this year’s field research. The fuller understanding of the environmental performance of these systems will help inform federal and state policies seeking to incentivize the development of a sustainable bioenergy industry.

  10. The impact of roots on soil organic carbon dynamics in annual and perennial agricultural systems

    NASA Astrophysics Data System (ADS)

    Beniston, J.; Dupont, T.; Glover, J.; Lal, R.

    2012-12-01

    Identifying and developing agricultural systems capable of transferring large quantities of carbon (C) to the soil and sustaining ecosystem processes and services is a priority for ecological researchers and land managers. Temperate grasslands have extensive root systems and transfer large quantities of C to the soil organic C (SOC) pool, which has lead to widespread interest in utilizing perennial grasses as both bioenergy crops and as a model for perennial grains. This study examined five sites in north central Kansas (U.S.A.) that contain the unique land use pairing of tall grass prairie meadows (PM) that have been harvested annually for hay for the past 75 years and annual grain (wheat) production fields (AG) that have been cultivated for a similar length of time, all on deep alluvial soils. Specific research objectives included: 1) To quantify below-ground biomass pools and root C contributions in the two systems; 2) To analyze and compare SOC pools and SOC concentration in primary particle size fractions in the two systems; 3) To utilize natural abundance δ13C signatures to determine the source and turnover of SOC in the soils of the AG sites; and 4) To elucidate the relationship of roots to both SOC pools and nematode food webs. Soil core samples were collected to a depth of 1 m in May and June 2008. Soil samples were analyzed for SOC, microbial biomass C (MBC), nematodes, and a particle size fractionation of SOC in coarse (>250 μm), particulate organic matter (POM) (53-250 μm), silt (2-53 μm), and clay (<2 μm) sized fractions. Root biomass, root length and root C were also analyzed to a depth of 1 m. Natural abundance δ13C values were obtained for all C parameters. Soils under PM had 4 times as much root C as AG soils to 1 m depth in mid May (PM 2.8 Mg ha-1 and AG 0.7 Mg ha-1) and 7 times as much root C to 1 m depth in late June (PM 3.5 Mg ha-1 and AG 0.5 Mg ha-1). The MBC pools were significantly larger in grassland soils to a depth of 60 cm in May

  11. Adaptability test of lettuce to soil-like substrate in bioregenerative life support system

    NASA Astrophysics Data System (ADS)

    Min, Yan; Liu, Professor Hong; Wenting, Fu

    Plant cultivation using soil-like substrate (SLS) is considered to be a feasible option for building up matter for biological turnover in bioregenerative life support system (BLSS) by many researchers. The characteristics of SLS are different from those of true soil therefore it is very important to study the adaptability of candidate crop to SLS in BLSS. This study was carried out in three successive steps to test the adaptability of lettuce (Lactuca sativa L.) to rice straw SLS in BLSS of China. First, six Chinese specific lettuce cultivars which were selected for Chinese advanced life support system were planted into the same rice straw SLS, which was to determine the more suitable plant cultivar to do the next experiment. The results showed that Sharp Leaf lettuce and Red lettuce were more suitable for SLS than other cultivars. Second, the possibility of increasing the crop yield on the SLS was conducted by changing the soil depth and plant density. Sharp Leaf lettuce and Red lettuce were used into this experiment in order to obtain the highest yield under the smallest soil volume and weight at the same light intensity. Crop edible biomass, crop nutrition content and photosynthetic characteristics were estimated during the experiment. Red lettuce obtained higher biomass and photosynthesis capacity. Lastly, the stability of planting system of lettuce and SLS was evaluated in the closed controlled system. Red lettuce would be the test plant. In this experiment different age lettuce groups would be planted together and gas exchange would be measured. In all of these experiments soil physical and chemical characteristics were also be measured which will be the basal data for further research.

  12. Impact of land management system on crop yields and soil fertility in Cameroon

    NASA Astrophysics Data System (ADS)

    Tsozué, D.; Nghonda, J. P.; Mekem, D. L.

    2015-06-01

    The impact of direct-seeding mulch-based cropping systems (DMC), direct seeding (DS) and tillage seeding (TS) on Sorghum yields, soil fertility and the rehabilitation of degraded soils was evaluated in northern Cameroon. Field work consisted of visual examination, soil sampling, yield and rainfall data collection. Three fertilization rates (F1: 100 kg ha-1 NPK + 25 kg ha-1 of urea in DMC, F2: 200 kg ha-1 NPK + 50 kg ha-1 of urea in DMC and F3: 300 kg ha-1 NPK + 100 kg ha-1 of urea in DMC) were applied to each cropping system (DS, TS and DMC), resulting in nine experimental plots. Two types of chemical fertilizer were used (NPK 22.10.15 and urea) and applied each year from 2002 to 2012. Average Sorghum yields were 1239, 863 and 960 kg ha-1 respectively in DMC, DS and TS at F1, 1658, 1139 and 1192 kg ha-1 respectively in DMC, DS and TS at F2, and 2270, 2138 and 1780 kg ha-1 respectively in DMC, DS and TS at F3. pH values were 5.2 to 5.7 under DMC, 4.9 to 5.3 under DS and TS, and 5.6 in the control sample. High values of cation exchange capacity were recorded in the control sample, TS system and F1 of DMC. Base saturation rates, total nitrogen and organic matter contents were high in the control sample and the DMC than in the others systems. All studied soils were permanently not suitable for Sorghum due to the high percentage of nodules. F1 and F2 of the DS were currently not suitable, while F1 and F3 of DMC, F3 of DS and F1, F2 and F3 of TS were marginally suitable for Sorghum due to low soil pH values.

  13. Dendrologic Effects on Soil Evolution Timescales and System Behavior in the Ouachita Mountains, USA

    NASA Astrophysics Data System (ADS)

    Marion, D. A.; Phillips, J. D.; Turkington, A. V.

    2008-12-01

    effects could potentially produce 100 percent turnover of the entire surface area within a time span of 3,000 yr. These dendrologic effects operate in ways that have direct bearing on ecogeomorphic system behavior, and have important implications for system modeling. Despite their widespread influence, there is strong evidence that trees have a non-random spatial impact over time due to a tendency for trees to reoccupy favorable sites. This results in dendrologic perturbations that are individually small and short lived, but whose effects are self-reinforcing and extend over time spans greatly exceeding that of the tree producing the initial effect. This dynamical instability produces non-equilibrium soil thicknesses and high pedodiversity within the region that is uncorrelated to landform-scale factors such as slope, aspect, vegetation type, or general lithology of underlying formations. While our results are contingent upon the landscape conditions of the Ouachita Mountains, they certainly suggest that dendrologic effects can be very important in understanding soil evolution in mountain forest systems and deserve serious consideration in any modeling effort.

  14. Soil biochemical properties and microbial resilience in agroforestry systems: effects on wheat growth under controlled drought and flooding conditions.

    PubMed

    Rivest, David; Lorente, Miren; Olivier, Alain; Messier, Christian

    2013-10-01

    Agroforestry is increasingly viewed as an effective means of maintaining or even increasing crop and tree productivity under climate change while promoting other ecosystem functions and services. This study focused on soil biochemical properties and resilience following disturbance within agroforestry and conventional agricultural systems and aimed to determine whether soil differences in terms of these biochemical properties and resilience would subsequently affect crop productivity under extreme soil water conditions. Two research sites that had been established on agricultural land were selected for this study. The first site included an 18-year-old windbreak, while the second site consisted in an 8-year-old tree-based intercropping system. In each site, soil samples were used for the determination of soil nutrient availability, microbial dynamics and microbial resilience to different wetting-drying perturbations and for a greenhouse pot experiment with wheat. Drying and flooding were selected as water stress treatments and compared to a control. These treatments were initiated at the beginning of the wheat anthesis period and maintained over 10 days. Trees contributed to increase soil nutrient pools, as evidenced by the higher extractable-P (both sites), and the higher total N and mineralizable N (tree-based intercropping site) found in the agroforestry compared to the conventional agricultural system. Metabolic quotient (qCO2) was lower in the agroforestry than in the conventional agricultural system, suggesting higher microbial substrate use efficiency in agroforestry systems. Microbial resilience was higher in the agroforestry soils compared to soils from the conventional agricultural system (windbreak site only). At the windbreak site, wheat growing in soils from agroforestry system exhibited higher aboveground biomass and number of grains per spike than in conventional agricultural system soils in the three water stress treatments. At the tree

  15. Soil biochemical properties and microbial resilience in agroforestry systems: effects on wheat growth under controlled drought and flooding conditions.

    PubMed

    Rivest, David; Lorente, Miren; Olivier, Alain; Messier, Christian

    2013-10-01

    Agroforestry is increasingly viewed as an effective means of maintaining or even increasing crop and tree productivity under climate change while promoting other ecosystem functions and services. This study focused on soil biochemical properties and resilience following disturbance within agroforestry and conventional agricultural systems and aimed to determine whether soil differences in terms of these biochemical properties and resilience would subsequently affect crop productivity under extreme soil water conditions. Two research sites that had been established on agricultural land were selected for this study. The first site included an 18-year-old windbreak, while the second site consisted in an 8-year-old tree-based intercropping system. In each site, soil samples were used for the determination of soil nutrient availability, microbial dynamics and microbial resilience to different wetting-drying perturbations and for a greenhouse pot experiment with wheat. Drying and flooding were selected as water stress treatments and compared to a control. These treatments were initiated at the beginning of the wheat anthesis period and maintained over 10 days. Trees contributed to increase soil nutrient pools, as evidenced by the higher extractable-P (both sites), and the higher total N and mineralizable N (tree-based intercropping site) found in the agroforestry compared to the conventional agricultural system. Metabolic quotient (qCO2) was lower in the agroforestry than in the conventional agricultural system, suggesting higher microbial substrate use efficiency in agroforestry systems. Microbial resilience was higher in the agroforestry soils compared to soils from the conventional agricultural system (windbreak site only). At the windbreak site, wheat growing in soils from agroforestry system exhibited higher aboveground biomass and number of grains per spike than in conventional agricultural system soils in the three water stress treatments. At the tree

  16. Development and application of screening tools for biodegradation in water-sediment systems and soil.

    PubMed

    Junker, Thomas; Coors, Anja; Schüürmann, Gerrit

    2016-02-15

    Two new screening-test systems for biodegradation in water-sediment systems (WSST; Water-Sediment Screening Tool) and soil (SST; Soil Screening Tool) were developed in analogy with the water-only test system OECD 301C (MITI-test). The test systems could be applied successfully to determine reproducible experimental mineralization rates and kinetics on the screening-test level for fifteen organic chemicals in water (MITI), water-sediment (WSST) and soil (SST). Substance-specific differences were observed for mineralization compared among the three test systems. Based on mineralization rate and mineralization half-life, the fifteen compounds could be grouped into four biodegradation categories: substances with high mineralization and a half-life <28 days in (1) all three test systems, (2) only in the MITI test and in the WSST, (3) only in the SST, and (4) none of the test systems. The observed differences between the MITI results and the WSST and SST biodegradation rates of the compounds do not reflect their (reversible) sorption into organic matter in terms of experimental K(oc) values and log D values for the relevant pH range. Regarding mineralization kinetics we recommend to determine the lag-phase, mineralization half-life and mineralization rate using a 5-parameter logistic regression for degradation curves with and without lag-phase. Experimental data obtained with the WSST and the SST could be verified by showing good agreement with biodegradation data from databases and literature for the majority of compounds tested. Thus, these new screening-tools for water-sediment and soil are considered suitable to determine sound and reliable quantitative mineralization data including mineralization kinetics in addition to the water-only ready biodegradability tests according to OECD 301.

  17. Development and application of screening tools for biodegradation in water-sediment systems and soil.

    PubMed

    Junker, Thomas; Coors, Anja; Schüürmann, Gerrit

    2016-02-15

    Two new screening-test systems for biodegradation in water-sediment systems (WSST; Water-Sediment Screening Tool) and soil (SST; Soil Screening Tool) were developed in analogy with the water-only test system OECD 301C (MITI-test). The test systems could be applied successfully to determine reproducible experimental mineralization rates and kinetics on the screening-test level for fifteen organic chemicals in water (MITI), water-sediment (WSST) and soil (SST). Substance-specific differences were observed for mineralization compared among the three test systems. Based on mineralization rate and mineralization half-life, the fifteen compounds could be grouped into four biodegradation categories: substances with high mineralization and a half-life <28 days in (1) all three test systems, (2) only in the MITI test and in the WSST, (3) only in the SST, and (4) none of the test systems. The observed differences between the MITI results and the WSST and SST biodegradation rates of the compounds do not reflect their (reversible) sorption into organic matter in terms of experimental K(oc) values and log D values for the relevant pH range. Regarding mineralization kinetics we recommend to determine the lag-phase, mineralization half-life and mineralization rate using a 5-parameter logistic regression for degradation curves with and without lag-phase. Experimental data obtained with the WSST and the SST could be verified by showing good agreement with biodegradation data from databases and literature for the majority of compounds tested. Thus, these new screening-tools for water-sediment and soil are considered suitable to determine sound and reliable quantitative mineralization data including mineralization kinetics in addition to the water-only ready biodegradability tests according to OECD 301. PMID:26774960

  18. Effects of different tillage and straw return on soil organic carbon in a rice-wheat rotation system.

    PubMed

    Zhu, Liqun; Hu, Naijuan; Yang, Minfang; Zhan, Xinhua; Zhang, Zhengwen

    2014-01-01

    Soil management practices, such as tillage method or straw return, could alter soil organic carbon (C) contents. However, the effects of tillage method or straw return on soil organic C (SOC) have showed inconsistent results in different soil/climate/cropping systems. The Yangtze River Delta of China is the main production region of rice and wheat, and rice-wheat rotation is the most important cropping system in this region. However, few studies in this region have been conducted to assess the effects of different tillage methods combined with straw return on soil labile C fractions in the rice-wheat rotation system. In this study, a field experiment was used to evaluate the effects of different tillage methods, straw return and their interaction on soil total organic C (TOC) and labile organic C fractions at three soil depths (0-7, 7-14 and 14-21 cm) for a rice-wheat rotation in Yangzhong of the Yangtze River Delta of China. Soil TOC, easily oxidizable C (EOC), dissolved organic C (DOC) and microbial biomass C (MBC) contents were measured in this study. Soil TOC and labile organic C fractions contents were significantly affected by straw returns, and were higher under straw return treatments than non-straw return at three depths. At 0-7 cm depth, soil MBC was significantly higher under plowing tillage than rotary tillage, but EOC was just opposite. Rotary tillage had significantly higher soil TOC than plowing tillage at 7-14 cm depth. However, at 14-21 cm depth, TOC, DOC and MBC were significantly higher under plowing tillage than rotary tillage except for EOC. Consequently, under short-term condition, rice and wheat straw both return in rice-wheat rotation system could increase SOC content and improve soil quality in the Yangtze River Delta.

  19. The development of a sub-surface monitoring system for organic contamination in soils and groundwater.

    PubMed

    Huntley, Sharon L; Ritchie, Lawrence J; Setford, Steven J; Saini, Selwayan

    2002-04-24

    A major problem when dealing with environmental contamination is the early detection and subsequent surveillance of the contamination. This paper describes the potential of sub-surface sensor technology for the early detection of organic contaminants in contaminated soils, sediments, and landfill sites. Rugged, low-power hydrocarbon sensors have been developed, along with a data-logging system, for the early detection of phase hydrocarbons in soil. Through laboratory-based evaluation, the ability of this system to monitor organic contamination in water-based systems is being evaluated. When used in conjunction with specific immunoassays, this can provide a sensitive and low-cost solution for long-term monitoring and analysis, applicable to a wide range of field applications.

  20. Neural network simulation of soil NO3 dynamic under potato crop system

    NASA Astrophysics Data System (ADS)

    Goulet-Fortin, Jérôme; Morais, Anne; Anctil, François; Parent, Léon-Étienne; Bolinder, Martin

    2013-04-01

    Nitrate leaching is a major issue in sandy soils intensively cropped to potato. Modelling could test and improve management practices, particularly as regard to the optimal N application rates. Lack of input data is an important barrier for the application of classical process-based models to predict soil NO3 content (SNOC) and NO3 leaching (NOL). Alternatively, data driven models such as neural networks (NN) could better take into account indicators of spatial soil heterogeneity and plant growth pattern such as the leaf area index (LAI), hence reducing the amount of soil information required. The first objective of this study was to evaluate NN and hybrid models to simulate SNOC in the 0-40 cm soil layer considering inter-annual variations, spatial soil heterogeneity and differential N application rates. The second objective was to evaluate the same methodology to simulate seasonal NOL dynamic at 1 m deep. To this aim, multilayer perceptrons with different combinations of driving meteorological variables, functions of the LAI and state variables of external deterministic models have been trained and evaluated. The state variables from external models were: drainage estimated by the CLASS model and the soil temperature estimated by an ICBM subroutine. Results of SNOC simulations were compared to field data collected between 2004 and 2011 at several experimental plots under potato cropping systems in Québec, Eastern Canada. Results of NOL simulation were compared to data obtained in 2012 from 11 suction lysimeters installed in 2 experimental plots under potato cropping systems in the same region. The most performing model for SNOC simulation was obtained using a 4-input hybrid model composed of 1) cumulative LAI, 2) cumulative drainage, 3) soil temperature and 4) day of year. The most performing model for NOL simulation was obtained using a 5-input NN model composed of 1) N fertilization rate at spring, 2) LAI, 3) cumulative rainfall, 4) the day of year and 5) the

  1. Reducing soil erosion and nutrient loss on sloping land under crop-mulberry management system.

    PubMed

    Fan, Fangling; Xie, Deti; Wei, Chaofu; Ni, Jiupai; Yang, John; Tang, Zhenya; Zhou, Chuan

    2015-09-01

    Sloping croplands could result in soil erosion, which leads to non-point source pollution of the aquatic system in the Three Gorges Reservoir Region. Mulberry, a commonly grown cash plant in the region, is traditionally planted in contour hedgerows as an effective management practice to control soil erosion and non-point source pollution. In this field study, surface runoff and soil N and P loss on sloping land under crop-mulberry management were investigated. The experiments consisted of six crop-mulberry treatments: Control (no mulberry hedgerow with mustard-corn rotation); T1 (two-row contour mulberry with mustard-corn rotation); T2 (three-row contour mulberry with mustard-corn rotation); T3 (border mulberry and one-row contour mulberry with mustard-corn rotation); T4 (border mulberry with mustard-corn rotation); T5 (two-row longitudinal mulberry with mustard). The results indicated that crop-mulberry systems could effectively reduce surface runoff and soil and nutrient loss from arable slope land. Surface runoff from T1 (342.13 m(3) hm(-2)), T2 (260.6 m(3) hm(-2)), T3 (113.13 m(3) hm(-2)), T4 (114 m(3) hm(-2)), and T5 (129 m(3) hm(-2)) was reduced by 15.4, 35.6, 72.0, 71.8, and 68.1%, respectively, while soil loss from T1 (0.21 t hm(-2)), T2 (0.13 t hm(-2)), T3 (0.08 t hm(-2)), T4 (0.11 t hm(-2)), and T5 (0.12 t hm(-2)) was reduced by 52.3, 70.5, 81.8, 75.0, and 72.7%, respectively, as compared with the control. Crop-mulberry ecosystem would also elevate soil N by 22.3% and soil P by 57.4%, and soil nutrient status was contour-line dependent.

  2. Directional reflectance factors for monitoring spatial changes in soil surface structure and soil organic matter erosion in agricultural systems

    NASA Astrophysics Data System (ADS)

    Croft, H.; Anderson, K.

    2012-04-01

    Soils can experience rapid structural degradation in response to land cover changes, resulting in reduced soil productivity, increased erodibility and a loss of soil organic matter (SOM). The breakdown of soil aggregates through slaking and raindrop impact is linked to organic matter turnover, with subsequently eroded material often displaying proportionally more SOM. A reduction in aggregate stability is reflected in a decline in soil surface roughness (SSR), indicating that a soil structural change can be used to highlight soil vulnerability to SOM loss through mineralisation or erosion. Accurate, spatially-continuous measurements of SSR are therefore needed at a variety of spatial and temporal scales to understand the spatial nature of SOM erosion and deposition. Remotely-sensed data can provide a cost-effective means of monitoring changes in soil surface condition over broad spatial extents. Previous work has demonstrated the ability of directional reflectance factors to monitor soil crusting within a controlled laboratory experiment, due to changes in the levels of self-shadowing effects by soil aggregates. However, further research is needed to test this approach in situ, where other soil variables may affect measured reflectance factors and to investigate the use of directional reflectance factors for monitoring soil erosion processes. This experiment assesses the potential of using directional reflectance factors to monitor changes in SSR, aggregate stability and soil organic carbon (SOC) content for two agricultural conditions. Five soil plots representing tilled and seedbed soils were subjected to different durations of natural rainfall, producing a range of different levels of SSR. Directional reflectance factors were measured concomitantly with sampling for soil structural and biochemical tests at each soil plot. Soil samples were taken to measure aggregate stability (wet sieving), SOC (loss on ignition) and soil moisture (gravimetric method). SSM

  3. Effects of biochar and elevated soil temperature on soil microbial activity and abundance in an agricultural system

    NASA Astrophysics Data System (ADS)

    Bamminger, Chris; Poll, Christian; Marhan, Sven

    2014-05-01

    As a consequence of Global Warming, rising surface temperatures will likely cause increased soil temperatures. Soil warming has already been shown to, at least temporarily, increase microbial activity and, therefore, the emissions of greenhouse gases like CO2 and N2O. This underlines the need for methods to stabilize soil organic matter and to prevent further boost of the greenhouse gas effect. Plant-derived biochar as a soil amendment could be a valuable tool to capture CO2 from the atmosphere and sequestrate it in soil on the long-term. During the process of pyrolysis, plant biomass is heated in an oxygen-low atmosphere producing the highly stable solid matter biochar. Biochar is generally stable against microbial degradation due to its chemical structure and it, therefore, persists in soil for long periods. Previous experiments indicated that biochar improves or changes several physical or chemical soil traits such as water holding capacity, cation exchange capacity or soil structure, but also biotic properties like microbial activity/abundance, greenhouse gas emissions and plant growth. Changes in the soil microbial abundance and community composition alter their metabolism, but likely also affect plant productivity. The interaction of biochar addition and soil temperature increase on soil microbial properties and plant growth was yet not investigated on the field scale. To investigate whether warming could change biochar effects in soil, we conducted a field experiment attached to a soil warming experiment on an agricultural experimental site near the University of Hohenheim, already running since July 2008. The biochar field experiment was set up as two-factorial randomized block design (n=4) with the factors biochar amendment (0, 30 t ha-1) and soil temperature (ambient, elevated=ambient +2.5° C) starting from August 2013. Each plot has a dimension of 1x1m and is equipped with combined soil temperature and moisture sensors. Slow pyrolysis biochar from the C

  4. [Effects of simulated acid rain on respiration rate of cropland system with different soil pH].

    PubMed

    Zhu, Xue-zhu; Zhang, Gao-chuan; Li, Hui

    2009-10-15

    To evaluate the effects of acid rain on the respiration rate of cropland system, an outdoor pot experiment was conducted with paddy soils of pH 5.48 (S1), pH 6.70 (S1) and pH 8.18 (S3) during the 2005-2007 wheat-growing seasons. The cropland system was exposed to acid rain by spraying the wheat foliage and irrigating the soil with simulated rainwater of T1 (pH 6.0), T2 (pH 6.0, ionic concentration was twice as rainwater T1), and T3 (pH 4.4, ionic concentration was twice as rainwater T1), respectively. The static opaque chamber-gas chromatograph method was used to measure CO2 fluxes from cropland system. The results showed that acid rain affected the respiration rate of cropland system through crop plant, and the cropland system could adapt to acid rain. Acid rainwater significantly increased the average respiration rate in alkaline soil (S3) cropland system, while it had no significant effects on the average respiration rate in neutral soil (S2) and acidic soil (S1) cropland systems. During 2005-2006, after the alkaline soil cropland system was treated with rainwater T3, the average respiration rate was 23.6% and 27.6% higher than that of alkaline soil cropland system treated with rainwater T1 and T2, respectively. During March to April, the respiration rate was enhanced with the increase of rainwater ionic concentration, while it was dropped with the decrease of rainwater pH value in acidic soil cropland system. It was demonstrated that soil pH and crop plant played important roles on the respiration rate of cropland system.

  5. [Effects of simulated acid rain on respiration rate of cropland system with different soil pH].

    PubMed

    Zhu, Xue-zhu; Zhang, Gao-chuan; Li, Hui

    2009-10-15

    To evaluate the effects of acid rain on the respiration rate of cropland system, an outdoor pot experiment was conducted with paddy soils of pH 5.48 (S1), pH 6.70 (S1) and pH 8.18 (S3) during the 2005-2007 wheat-growing seasons. The cropland system was exposed to acid rain by spraying the wheat foliage and irrigating the soil with simulated rainwater of T1 (pH 6.0), T2 (pH 6.0, ionic concentration was twice as rainwater T1), and T3 (pH 4.4, ionic concentration was twice as rainwater T1), respectively. The static opaque chamber-gas chromatograph method was used to measure CO2 fluxes from cropland system. The results showed that acid rain affected the respiration rate of cropland system through crop plant, and the cropland system could adapt to acid rain. Acid rainwater significantly increased the average respiration rate in alkaline soil (S3) cropland system, while it had no significant effects on the average respiration rate in neutral soil (S2) and acidic soil (S1) cropland systems. During 2005-2006, after the alkaline soil cropland system was treated with rainwater T3, the average respiration rate was 23.6% and 27.6% higher than that of alkaline soil cropland system treated with rainwater T1 and T2, respectively. During March to April, the respiration rate was enhanced with the increase of rainwater ionic concentration, while it was dropped with the decrease of rainwater pH value in acidic soil cropland system. It was demonstrated that soil pH and crop plant played important roles on the respiration rate of cropland system. PMID:19968099

  6. Treatment of dirty water from dairy farms using a soil-based batch recirculation system.

    PubMed

    Tyrrel, S F; Leeds-Harrison, P B

    2005-01-01

    "Dirty water", a wastewater produced on dairy farms, is typically disposed of by application to land with no prior treatment. Pollution can occur if the dirty water reaches a watercourse following an inadequate period of retention in the soil. This paper describes experiments using a novel, soil-based batch recirculation system for pre-treating dirty water prior to land application. Three polythene-lined, vegetated soil-based treatment planes (23 m long, 1 m wide, 0.25 m deep) were constructed. Each treatment plane was supplied with approximately 1 m3 of dirty water which was recirculated until a clear treatment pattern had emerged. Five batches were treated over a six-month period. The soil-based treatment system could typically be expected to achieve a 90% removal of key pollutants in approximately two weeks for BODs and NH4-N, and three weeks for MRP and total solids. An exponential trendline gave a good fit to the treatment curves for BOD5, NH4-N and MRP after the first day or two of batch treatment. The data for total solids removal were more variable. Treatment rates were sustained throughout the five runs for BOD5 and NH4-N, indicating no apparent effect of seasonal weather on the treatment process. The apparent progressive slowing of the MRP removal rate throughout the treatment of the five batches may have implications for the sustainable use of this technology for phosphorus control.

  7. Modern state of the soils of flood irrigation systems in the semidesert zone

    NASA Astrophysics Data System (ADS)

    Nasiev, B. N.; Eleshev, R.

    2014-06-01

    The data of two soil and vegetation surveys of flood basins of the Mamai irrigation system performed in 1987 and 2012 are compared. This irrigation system is found within the Caspian Lowland in Western Kazakhstan oblast of Kazakhstan. The thickness of the humus horizon decreased by 4 cm on the average attesting to the first-second stages of soil degradation. The humus content in the A + B1 horizons decreased by 0.3% on the average with variations corresponding to the first-third degradation stages. From 1987 to 2012, the area of saline soils and the content of exchangeable sodium in them also increased attesting to the development of desertification in the studied zone. The flooded portion of flood basins decreased from 84% in 1987 to 69% in 2012, and the groundwater level rose from 3.6-4.0 to 1.8-3.1 m. Soil degradation processes, together with adverse anthropogenic impacts, resulted in a decrease in the projective cover of valuable plant species and the productivity of herbs grown in flood basins.

  8. Situ soil sampling probe system with heated transfer line

    DOEpatents

    Robbat, Jr., Albert

    2002-01-01

    The present invention is directed both to an improved in situ penetrometer probe and to a heated, flexible transfer line. The line and probe may be implemented together in a penetrometer system in which the transfer line is used to connect the probe to a collector/analyzer at the surface. The probe comprises a heater that controls a temperature of a geologic medium surrounding the probe. At least one carrier gas port and vapor collection port are located on an external side wall of the probe. The carrier gas port provides a carrier gas into the geologic medium, and the collection port captures vapors from the geologic medium for analysis. In the transfer line, a flexible collection line that conveys a collected fluid, i.e., vapor, sample to a collector/analyzer. A flexible carrier gas line conveys a carrier gas to facilitate the collection of the sample. A system heating the collection line is also provided. Preferably the collection line is electrically conductive so that an electrical power source can generate a current through it so that the internal resistance generates heat.

  9. Soil acidity amelioration in a no-till system in west Tennessee USA differs by cover crop type and nitrogen application rate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation soil management practices may influence the soil acidity. Surface application of lime may be required in no-till systems to ameliorate soil acidity and to improve crop yields. The application of lime may also increase microbial activity on soil. Specifically, the microbial activity of s...

  10. Investigation of the degradation of 13C-labeled fungal biomass in soil - fate of carbon in a soil bioreactor system

    NASA Astrophysics Data System (ADS)

    Schweigert, Michael; Fester, Thomas; Miltner, Anja; Kästner, Matthias

    2014-05-01

    Nutrient balances and degradation processes in boreal forests are mainly influenced by interactions of plant roots and ectomycorrhizal fungi. Plants benefit from nitrogen compounds provided by their symbiotic interaction partner. In return ectomycorrhiza are provided by large amounts of carbon from the plants which is used for the synthesis of hyphal networks in soil and for metabolic activity for nutrient uptake. Therefore ectomycorrhizal fungi play a major role in ecosystems of boreal forests and are consequently an important sink for carbon by building large amounts of mycelia. Recently, it has been shown that microbial biomass residues contribute significantly to soil organic matter formation. This suggests that also residues of ectomycorrhizal fungi may be an important source for soil organic matter formation in forest soils where these fungi are abundant. However, the fate of ectomycorrhizal biomass residues in soils is unknown. We therefore investigated the fate of ectomycorrhizal biomass in soil in a bioreactor system to quantify the contribution of this material to soil organic matter formation. As a model organism, we selected Laccaria bicolor, which was labelled by growing the fungus on 13C glucose. The stable isotope-labeled biomass was then homogenized and incubated in a podzol from a typical forest site in Central Germany. The fate of the labeled biomass was traced by analyzing the amount of 13C mineralized and the amount remaining in the soil. The fungal biomass carbon was mineralized rather rapidly during the first 25 days. Then the mineralization rate slowed down, but mineralization continued until the end of the experiment, when approximately 40% of the 13C was mineralized and 60% remained in soil. In addition, we analyzed biomolecules such as fatty acids to trace the incorporation of the L. bicolor-derived biomass carbon into other microorganisms and to identify potential primary consumers of fungal biomass. By these analyses, we found a

  11. Testing fungistatic properties of soil-like substrate for growing plants in bioregenerative life support systems

    NASA Astrophysics Data System (ADS)

    Enzhu, Hu; Nesterenko, Elena; Liu, Professor Hong; Manukovsky, N. S.; Kovalev, Vladimir; Gurevich, Yu.; Kozlov, Vladimir; Khizhnyak, Serge; Xing, Yidong; Hu, Enzhu; Enzhu, Hu

    There are two ways of getting vegetable food in BLSS: in hydroponic culture and on soil substrates. In any case there is a chance that the plants will be affected by plant pathogenic microorganisms. The subject of the research was a soil-like substrate (SLS) for growing plants in a Bioregenerative Life Support System (BLSS). We estimated the fungistatic properties of SLS using test cultures of Bipolaris and Alternaria plant pathogenic fungi. Experiments were made with the samples of SLS, natural soil and sand (as control). We tested 2 samples of SLS produced by way of bioconversion of wheat and rice straw. We measured the disease severity of wheat seedlings and the incidence of common root rot in natural (non-infectious) background and man-made (infectious) conditions. The severity of disease on the SLS was considerably smaller both in non-infectious and infectious background conditions (8 and 12%) than on the natural soil (18 and 32%) and sand. It was the soil-like substrate that had the minimal value among the variants being compared (20% in non-infectious and 40% in infectious background conditions). This index in respect of the soil was 55 and 78%, correspondingly, and in respect of the sand - 60%, regardless of the background. It was found that SLS significantly suppressed conidia germination of Bipolaris soroikiniana (p<0.001). In the presence of SLS germination of conidia decreased to 9.9 - 12.2% of the control value. No significant differences were found between SLS samples obtained from wheat and rice straw.

  12. Development of long-wave microwave satellite systems for measuring soil moisture

    NASA Astrophysics Data System (ADS)

    Engman, Edwin T.

    1998-12-01

    The science need for remotely sensed soil moisture has been well established in the hydrologic, climate change and weather forecasting communities. There also have been a number of programs that have demonstrated the feasibility of using long wave microwave sensors for estimating soil moisture. These have ranged from truck mounted sensors, to intensive airborne campaigns with science objectives. Based on this history of truck and aircraft experiments, the science community has settled on a soil moisture product that meets the following criteria: a two day global repeat, a measured layer of 5 cm of soil, a footprint of 20 to 30 km, and an absolute accuracy of plus or minus 4% volumetric soil moisture. The principal sensor to accomplish this is an L-band passive microwave radiometer. A soil moisture mission is being proposed for the NASA Earth Systems Science Pathfinder (ESSP) mission which has very real constraints of a limited budget which includes the launch vehicle, and a three year award to launch time schedule. Within the past few years there have been a number of mission concepts proposed that meet the challenge of getting a very large antenna in space in order to realize a spatial resolution on the ground that meets the science and applications needs. This paper describes some of the alternative concepts considered to meet these unusual requirements and the ways to solve the very large antenna challenge, and the criteria used to choose the final design for an ESSP proposal. The paper also discusses the alternatives considered to obtain the necessary ancillary data for characterizing the surface roughness, the surface temperature and the attenuation affects of vegetation.

  13. Quantitative analysis of the impact of three tillage systems on soil structure using X-ray tomography

    NASA Astrophysics Data System (ADS)

    Le Couteulx, Alexis; Pérès, Guénola; Wolf, Cédric; Hallaire, Vincent

    2015-04-01

    Soil structure is a dynamic property that can be altered by various structuring processes. Among other processes, there are soil tillage, soil organisms (e.g. earthworm bioturbation) and climate (e.g. freeze-thaw cycles). In cultivated fields, it is often acknowledged that soil tillage is a main structuring process, indeed in a very short time soil tillage can drastically altered soil structure. Despite this, the direct effect of tillage on soil structure through the mechanical action of tillage tools is seldom studied. Thus, this study aims at describing the effect of tillage tools used in three different tillage systems (ploughing, surface tillage and direct seedling). Their effect on soil structure is analysed by X-ray computed tomography (CT). In our study, the ploughing and surface tillage systems consist in two tillage actions at different times: first the ploughing or the use of a tined tool and then the sowing combined with a rotary harrow. On the contrary, there is only one tillage action under the direct seedling system: the sowing. Soil columns were taken before and after each tillage action and then analysed by CT (spatial resolution of 0.3x0.3x0.1 mm). We first analysed the macroporosity and noticeably root and earthworm burrow paths. Algorithms developped in other studies to analyse earthworm burrows allowed us to measure the length, volume, continuity and branching rate of these paths. First results show that there are very few paths in the tilled layer after ploughing and surface tillage. These paths are short, seldom connected to soil surface and mainly in dense aggregates suggesting that they can weakly improve soil water conductivity. Under direct seedling, we observed that there is a disturbed volume around the seed furrow that removed several paths but this impact is weaker than after the other tillage tools. Acquired knowledges will be used to build a model that accounts for the impact of tillage practices and earthworm bioturbation on soil

  14. Modelling global change impacts on soil carbon contents of agro-silvo-pastoral Mediterranean systems

    NASA Astrophysics Data System (ADS)

    Lozano-García, Beatriz; Muñoz-Rojas, Miriam; Parras-Alcántara, Luis

    2016-04-01

    To assess the impact of climate change on soil organic C (SOC) stocks in agro-silvo-pastoral environments, different models have been applied worldwide at local or regional scales, such as as RothC (Francaviglia et al., 2012) or CENTURY (Alvaro-Fuentes et al., 2012). However, some of these models may require a high number of input parameters or can underestimate the effect of soil depth. CarboSOIL (Muñoz-Rojas et al., 2013) is an empirical model based on regression techniques and developed to predict SOC contents at standard soil depths (0-25, 25-50 and 50-75 cm) under a range of climate and/or land use change scenarios. CarboSOIL has been successfully applied in different Mediterranean areas ,e.g. Southern Spain (Muñoz-Rojas et al., 2013; Abd-Elmabod et al., 2014), Northern Egypt (Muñoz-Rojas et al., 2014) and Italy (Muñoz-Rojas et al., 2015). In this study, CarboSOIL was applied in the Cardeña and Montoro mountain range Natural Park. This area covers 385 km2 and is located within Sierra Morena (Córdoba, South Spain) and has a semiarid Mediterranean climate. It is characterized by agro-silvo-pastoral systems. The Mediterranean evergreen oak woodland (MEOW-dehesa) is savanna-like open woodland ecosystem characterized by silvopastoral uses, being an ancient human modified Mediterranean landscape (Corral-Fernández et al., 2013; Lozano-García and Parras-Alcántara 2013). The most representative soils in the Cardeña and Montoro mountain range Natural Park are Cambisols, Regosols, Leptosols and Fluvisols. These soils are characterized by low fertility, poor physical conditions and marginal capacity for agricultural use, together with low organic matter (OM) content due to climate conditions (semiarid Mediterranean climate) and soil texture (sandy). The model was applied at different soil depths: 0-25, 25-50 and 50-75 cm (Parras-Alcántara et al., 2015) considering land use and climate changes scenarios based on available global climate models (IPPC, 2007). A

  15. Poly-use multi-level sampling system for soil-gas transport analysis in the vadose zone.

    PubMed

    Nauer, Philipp A; Chiri, Eleonora; Schroth, Martin H

    2013-10-01

    Soil-gas turnover is important in the global cycling of greenhouse gases. The analysis of soil-gas profiles provides quantitative information on below-ground turnover and fluxes. We developed a poly-use multi-level sampling system (PMLS) for soil-gas sampling, water-content and temperature measurement with high depth resolution and minimal soil disturbance. It is based on perforated access tubes (ATs) permanently installed in the soil. A multi-level sampler allows extraction of soil-gas samples from 20 locations within 1 m depth, while a capacitance probe is used to measure volumetric water contents. During idle times, the ATs are sealed and can be equipped with temperature sensors. Proof-of-concept experiments in a field lysimeter showed good agreement of soil-gas samples and water-content measurements compared with conventional techniques, while a successfully performed gas-tracer test demonstrated the feasibility of the PMLS to determine soil-gas diffusion coefficients in situ. A field application of the PMLS to quantify oxidation of atmospheric CH4 in a field lysimeter and in the forefield of a receding glacier yielded activity coefficients and soil-atmosphere fluxes well in agreement with previous studies. With numerous options for customization, the presented tool extends the methodological choices to investigate soil-gas transport in the vadose zone. PMID:23962070

  16. Poly-use multi-level sampling system for soil-gas transport analysis in the vadose zone.

    PubMed

    Nauer, Philipp A; Chiri, Eleonora; Schroth, Martin H

    2013-10-01

    Soil-gas turnover is important in the global cycling of greenhouse gases. The analysis of soil-gas profiles provides quantitative information on below-ground turnover and fluxes. We developed a poly-use multi-level sampling system (PMLS) for soil-gas sampling, water-content and temperature measurement with high depth resolution and minimal soil disturbance. It is based on perforated access tubes (ATs) permanently installed in the soil. A multi-level sampler allows extraction of soil-gas samples from 20 locations within 1 m depth, while a capacitance probe is used to measure volumetric water contents. During idle times, the ATs are sealed and can be equipped with temperature sensors. Proof-of-concept experiments in a field lysimeter showed good agreement of soil-gas samples and water-content measurements compared with conventional techniques, while a successfully performed gas-tracer test demonstrated the feasibility of the PMLS to determine soil-gas diffusion coefficients in situ. A field application of the PMLS to quantify oxidation of atmospheric CH4 in a field lysimeter and in the forefield of a receding glacier yielded activity coefficients and soil-atmosphere fluxes well in agreement with previous studies. With numerous options for customization, the presented tool extends the methodological choices to investigate soil-gas transport in the vadose zone.

  17. A versatile system for biological and soil chemical tests on a planetary landing craft. II - Hardware development

    NASA Technical Reports Server (NTRS)

    Martin, J. P.; Kok, B.; Radmer, R.

    1976-01-01

    A system has been under development which is designed to seek remotely for clues to life in planetary soil samples. The basic approach is a set of experiments, all having a common sensor, a gas analysis mass spectrometer which monitors gas composition in the head spaces above sealed, temperature controlled soil samples. Versatility is obtained with up to three preloaded, sealed fluid injector capsules for each of eleven soil test cells. Tests results with an engineering model has demonstrated performance capability of subsystem components such as soil distribution, gas sampling valves, injector mechanisms, temperature control, and test cell seal.

  18. A versatile system for biological and soil chemical tests on a planetary landing craft. I - Scientific objectives

    NASA Technical Reports Server (NTRS)

    Radmer, R. J.; Kok, B.; Martin, J. P.

    1976-01-01

    We describe an approach for the remote detection and characterization of life in planetary soil samples. A mass spectrometer is used as the central sensor to monitor changes in the gas phase in eleven test cells filled with soil. Many biological assays, ranging from general 'in situ' assays to specific metabolic processes (such as photosynthesis, respiration, denitrification, etc.) can be performed by appropriate additions to the test cell via attached preloaded injector capsules. The system is also compatible with a number of chemical assays such as the analysis of atmospheric composition (both chemical and isotopic), the status of soil water, and the determination of compounds of carbon, nitrogen and sulfur in the soil.

  19. Systemic induction of monoterpene biosynthesis in Origanumxmajoricum by soil bacteria.

    PubMed

    Banchio, Erika; Bogino, Pablo C; Santoro, Maricel; Torres, Lorena; Zygadlo, Julio; Giordano, Walter

    2010-01-13

    Italian oregano (Origanumxmajoricum) was subjected to root system inoculation with three species of plant growth-promoting rhizobacteria (PGPRs) (Pseudomonas fluorescens, Bacillus subtilis, Azospirillum brasilense), and essential oil (EO) content and plant growth were measured. Composition of monoterpenes, a major EO component, was analyzed qualitative and quantitatively by gas chromatography. Total EO yield for plants inoculated with P. fluorescens or A. brasilense was 3.57 and 3.41 microg/mg fresh weight, respectively, approximately 2.5-fold higher than controls, without change of quantitative oil composition. The major EO compounds, cis- and trans-sabinene hydrate, gamma-terpinene, carvacrol, and thymol, showed increased biosynthesis. Carvacrol was the only terpene showing significant increase of R% in plants inoculated with A. brasilense. Plant growth parameters (shoot and root fresh and dry weights, numbers of leaves and nodes) were evaluated. Shoot fresh weight was significantly increased by all three PGPR species, but only P. fluorescens and A. brasilense increased root dry weight. These two species have clear commercial potential for economic cultivation of O.xmajoricum. Knowledge of the factors affecting yield and accumulation of monoterpenes is essential for improving production of these economically important plant compounds. PMID:20000572

  20. FT-IR and C-13 NMR analysis of soil humic fractions from a long term cropping systems study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increased knowledge of humic fractions is important due to its involvement in many soil ecosystem processes. Soil humic acid (HA) and fulvic acid (FA) from a nine-year agroecosystem study with different tillage, cropping system, and N source treatments were characterized using FT-IR andsolid-state ...

  1. Residue and soil carbon sequestration in relation to crop yield as affected by irrigation, tillage, cropping system and nitrogen fertilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Information on management practices is needed to increase surface residue and soil C sequestration to obtain farm C credit. The effects of irrigation, tillage, cropping system, and N fertilization were evaluated on the amount of crop biomass (stems and leaves) returned to the soil, surface residue C...

  2. Development of an NDIR CO2 Sensor-Based System for Assessing Soil Toxicity Using Substrate-Induced Respiration

    PubMed Central

    Kaur, Jasmeen; Adamchuk, Viacheslav I.; Whalen, Joann K.; Ismail, Ashraf A.

    2015-01-01

    The eco-toxicological indicators used to evaluate soil quality complement the physico-chemical criteria employed in contaminated site remediation, but their cost, time, sophisticated analytical methods and in-situ inapplicability pose a major challenge to rapidly detect and map the extent of soil contamination. This paper describes a sensor-based approach for measuring potential (substrate-induced) microbial respiration in diesel-contaminated and non-contaminated soil and hence, indirectly evaluates their microbial activity. A simple CO2 sensing system was developed using an inexpensive non-dispersive infrared (NDIR) CO2 sensor and was successfully deployed to differentiate the control and diesel-contaminated soils in terms of CO2 emission after glucose addition. Also, the sensor system distinguished glucose-induced CO2 emission from sterile and control soil samples (p ≤ 0.0001). Significant effects of diesel contamination (p ≤ 0.0001) and soil type (p ≤ 0.0001) on glucose-induced CO2 emission were also found. The developed sensing system can provide in-situ evaluation of soil microbial activity, an indicator of soil quality. The system can be a promising tool for the initial screening of contaminated environmental sites to create high spatial density maps at a relatively low cost. PMID:25730479

  3. Microbial community structure and abundance in the rhizosphere and bulk soil of a tomato cropping system that includes cover crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this report we use Terminal Restriction Fragment Length Polymorphisms (TRFLP) in a tomato production system to “finger printing” the soil microbial community structure with Phylum specific primer sets. Factors influencing the soil microbes are a cover crop of Hairy Vetch (Vicia villosa) or Rye (...

  4. Carbon, nitrogen, organic phosphorus, microbial biomass and N mineralization in soils under cacao agroforestry systems in Bahia, Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding the soil organic P cycle is important to improve the P fertilization management in low-input tropical agricultural systems. The aim of this study was to evaluate organic P (Po) content by Bowman extraction method and labile P fractions by NaHCO3 extraction in soil profiles under cacao ...

  5. Cumulative and residual effects of potato cropping system management strategies on soil physical, chemical, and biological properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In field trials established in 2004, different 3-yr potato cropping systems focused on specific management goals of soil conservation (SC), soil improvement (SI), and disease-suppression (DS) were evaluated and compared to a 2-yr standard rotation (SQ) and a non-rotation control (PP) for their effec...

  6. Energy-dispersive X-ray fluorescence systems as analytical tool for assessment of contaminated soils.

    PubMed

    Vanhoof, Chris; Corthouts, Valère; Tirez, Kristof

    2004-04-01

    To determine the heavy metal content in soil samples at contaminated locations, a static and time consuming procedure is used in most cases. Soil samples are collected and analyzed in the laboratory at high quality and high analytical costs. The demand by government and consultants for a more dynamic approach and by customers requiring performances in which analyses are performed in the field with immediate feedback of the analytical results, is growing. Especially during the follow-up of remediation projects or during the determination of the sampling strategy, field analyses are advisable. For this purpose four types of ED-XRF systems, ranging from portable up to high performance laboratory systems, have been evaluated. The evaluation criteria are based on the performance characteristics for all the ED-XRF systems such as limit of detection, accuracy and the measurement uncertainty on one hand, and also the influence of the sample pretreatment on the obtained results on the other hand. The study proved that the field portable system and the bench top system, placed in a mobile van, can be applied as field techniques, resulting in semi-quantitative analytical results. A limited homogenization of the analyzed sample significantly increases the representativeness of the soil sample. The ED-XRF systems can be differentiated by their limits of detection which are a factor of 10 to 20 higher for the portable system. The accuracy of the results and the measurement uncertainty also improved using the bench top system. Therefore, the selection criteria for applicability of both field systems are based on the required detection level and also the required accuracy of the results.

  7. Heavy metal characteristics in Kočani Field soil-plant system (Republic of Macedonia)

    NASA Astrophysics Data System (ADS)

    Rogan Šmuc, Nastja; Dolenec, Tadej; Serafimovski, Todor; Tasev, Goran; Dolenec, Matej; Komar, Darja; Vrhovnik, Petra

    2014-05-01

    Contamination of soils with heavy metals is globally widespread and induces a long-term risk to ecosystem health. This research focuses on the heavy metal contamination, transfer values and health risk assessment in the Kočani Field soil-plant system (Republic of Macedonia). To identify the heavy metal concentrations in Kočani soils and crops (rice and maize) the geochemical analysis were performed by inductive coupled plasma mass spectrometer (ICP-MS), thereupon the transfer factor (TF) and estimated daily intake amount (EDIA) values in Kočani crops were calculated. Heavy metal contamination status of Kočani soils was also assessed by using sequential extraction procedure and by several environmental indexes: geoaccumulation index, contamination factor and contamination degree. The detected total concentrations of As, Cu, Cd, Pb and Zn in soil samples were highly above the threshold values considered to be phytotoxically excessive for the surface soils. The results of the applied indexes confirmed a very high contamination status for Kočani soils. According to the sum of the water soluble (1) and exchangeable (2) fractions for Ag, As, Cd, Cu, Mo, Ni, Pb, Sb and Zn measured in the soils, the mobility and bioavailability potential of the heavy metals studied declined in the following order: Cd > Mo > Sb > Zn > Cu > As > Pb > Ni > Ag. The highest As, Cd, Mo, Pb and Zn values were determined in the rice samples grown in the paddy fields near the Zletovska River. The highest Pb and Mo concentrations measured in the maize samples were from the maize fields near the Zletovska River and Ciflik city. High transfer factor v