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Sample records for soil petrophysical parameters

  1. Methods for estimating petrophysical parameters from well logs in tight oil reservoirs: a case study

    NASA Astrophysics Data System (ADS)

    Zhao, Peiqiang; Zhuang, Wen; Sun, Zhongchun; Wang, Zhenlin; Luo, Xingping; Mao, Zhiqiang; Tong, Zemin

    2016-02-01

    Estimating petrophysical parameters from well logs plays a significant role in the exploration and development of tight oil resources, but faces challenges. What’s more, the methods for petrophysical parameters from well logs are paid little attention at present. In this paper, the typical tight oil reservoirs of Northwest China are used as an example. Based on the characteristics of mineralogy and fluids in the study field, the rock is assumed into five components which are clays, quartz and feldspar, carbonates, kerogen and pore fluids (porosity). The sum of kerogen content and porosity is defined as the apparent porosity. Then, two porosity log response equations are established. Once the clay content is determined by an individual method, the quartz and feldspar content, carbonate content and apparent porosity are calculated through the established equations. The kerogen content is the difference of the apparent porosity and porosity from nuclear magnetic resonance (NMR) logs. This paper also presents a new approach that combines the complex refractive index method (CRIM) and pseudo Archie method to compute saturation from dielectric logs, which avoids selection for the dielectric constants of each of the minerals. The effectiveness and reliability of these methods are verified by the successful application in the study of the target tight oil play in Northwest China.

  2. Resolution dependence of petrophysical parameters derived from X-ray tomography of chalk

    SciTech Connect

    Müter, D.; Sørensen, H. O.; Jha, D.; Harti, R.; Dalby, K. N.; Stipp, S. L. S.; Suhonen, H.; Feidenhans'l, R.; Engstrøm, F.

    2014-07-28

    X-ray computed tomography data from chalk drill cuttings were taken over a series of voxel dimensions, ranging from 320 to 25 nm. From these data sets, standard petrophysical parameters (porosity, surface area, and permeability) were derived and we examined the effect of the voxel dimension (i.e., image resolution) on these properties. We found that for the higher voxel dimensions, they are severely over or underestimated, whereas for 50 and 25 nm voxel dimension, the resulting values (5%–30% porosity, 0.2–2 m{sup 2}/g specific surface area, and 0.06–0.34 mD permeability) are within the expected range for this type of rock. We compared our results to macroscopic measurements and in the case of surface area, also to measurements using the Brunauer-Emmett-Teller (BET) method and found that independent of the degree of compaction, the results from tomography amount to about 30% of the BET method. Finally, we concluded that at 25 nm voxel dimension, the essential features of the nanoscopic pore network in chalk are captured but better resolution is still needed to derive surface area.

  3. Petrophysical database of Uganda

    NASA Astrophysics Data System (ADS)

    Ruotoistenmäki, Tapio; Birungi, Nelson R.

    2015-06-01

    The petrophysical database of Uganda contains data on ca. 5800 rock samples collected and analyzed during 2009-2012 in international geological and geophysical projects covering the main part of the land area of Uganda. The parameters included are the susceptibilities and densities of all available field samples. Susceptibilities were measured from the samples from three directions. Using these parameters, we also calculated the ratios of susceptibility maxima/minima reflecting direction homogeneity of magnetic minerals, and estimated the iron content of paramagnetic samples and the magnetite content of ferrimagnetic samples. Statistical and visual analysis of the petrophysical data of Uganda demonstrated their wide variation, thus emphasizing their importance in analyzing the bedrock variations in three dimensions. Using the density-susceptibility diagram, the data can be classified into six main groups: 1. A low density and susceptibility group, consisting of sedimentary and altered rocks. 2. Low-susceptibility, felsic rocks (e.g. quartzites and metasandstones). 3. Paramagnetic, felsic rocks (e.g. granites). 4. Ferrimagnetic, magnetite-containing felsic rocks (e.g. granites). 5. Paramagnetic mafic rocks (e.g. amphibolites and dolerites). 6. Ferrimagnetic, mafic rocks containing magnetite and high-density mafic minerals (mainly dolerites). Moreover, analysis revealed that the parameter distributions of even a single rock type (e.g. granites) can be very variable, forming separate clusters. This demonstrates that the simple calculation of density or susceptibility averages of rock types can be highly erratic. For example, the average can lie between two groups, where only few, if any, samples exist. Therefore, estimation of the representative density and susceptibility must be visually verified from these diagrams. The areal distribution of parameters and their calculated derivatives generally correlate well with the regional distribution of lithological and

  4. Parameter selection and testing the soil water model SOIL

    NASA Astrophysics Data System (ADS)

    McGechan, M. B.; Graham, R.; Vinten, A. J. A.; Douglas, J. T.; Hooda, P. S.

    1997-08-01

    The soil water and heat simulation model SOIL was tested for its suitability to study the processes of transport of water in soil. Required parameters, particularly soil hydraulic parameters, were determined by field and laboratory tests for some common soil types and for soils subjected to contrasting treatments of long-term grassland and tilled land under cereal crops. Outputs from simulations were shown to be in reasonable agreement with independently measured field drain outflows and soil water content histories.

  5. Relating pore-scale geometric controls on NMR and SIP parameters for improved petrophysical models of synthetic sand-clay mixtures

    NASA Astrophysics Data System (ADS)

    Osterman, G. K.; Keating, K.; Slater, L. D.; Binley, A. M.

    2013-12-01

    The microgeometry of porous geologic materials controls a wide range of key hydraulic parameters, such as permeability. Non-invasive geophysical methods have shown promise in mapping these properties in-situ over laterally extensive areas. Two near-surface geophysical techniques, nuclear magnetic resonance (NMR) and spectral induced polarization (SIP), demonstrate distinct relationships with porosity, grain size, and surface area. Permeability is also thought to be related to these physical properties suggesting that NMR and SIP can be used to estimate permeability. However, SIP lacks a universally accepted model and NMR is insensitive to anisotropy and pore-connectivity. Additionally, geochemical factors alter NMR and SIP measurements in non-unique manners. In this study, we performed a series of laboratory experiments on well-controlled sand-clay mixtures in order to constrain the geometric controls on measureable NMR and SIP responses in porous media. We combined the geophysical data to formulate better petrophysical models of key hydraulic parameters than would be possible using each method separately. NMR and SIP measurements were performed on different brine saturated mixtures of Ottawa sand and kaolin. Independent measurements were made to estimate the specific surface area, porosity, grain size distribution, and permeability for each sand-clay mixture. Additionally, the brine conductivity was varied in order to test the sensitivity of the NMR and SIP measurements to pore-fluid chemistry as well as determine the true electrical formation factor of the samples. Empirical relationships were first established between each physical property and the measured geophysical parameters using regression analysis. The resulting relationships form the foundation for future mechanistic permeability models that incorporate joint NMR and SIP measurements.

  6. Electrical and Petrophysical modeling of Ferron Sandstone data

    NASA Astrophysics Data System (ADS)

    Szerbiak, R. B.; McMechan, G. A.; Forster, C. B.; Snelgrove, S. H.

    2006-05-01

    As part of the 3-D characterization of a fluvial reservoir analog site in the Ferron Sandstone in east-central Utah, new lab measurements of porosity, permeability, water content, and complex dielectric permittivity are collected and analyzed. Petrographic analysis of thin sections extracted from the same samples produced data on bulk, macro- and micro-porosity, lithology, and cementation. Thus, we have an unusually comprehensive data base for analysis. Complex dielectric permittivities are fitted using three frequency- dependent Debye relaxation mechanisms. Most ambient and dry samples are dominated by low-frequency relaxation mechanisms. The average dielectric constant and electrical conductivity at the typical GPR frequency of 75 MHz, are directly related to volumetric water content and are 3.86 and 0.20 mS/m for ovendried samples, 4.50 and 0.71 mS/m for ambient saturated samples, and 15.42 and 13.11 mS/m for fully saturated samples. Electrical conductivity is poorly estimated from the ovendried samples (for all clay content) since ion mobility is significantly reduced; thus, the dry conductivity is less useful for estimating petrophysical variations. Multivariate regressions with the petrophysical parameters estimate the electrical properties at 75 MHz and 1000 MHz with average correlation coefficients of ~0.921 and ~0.925, respectively. Empirically derived predictions of dielectric constant as a function of water content will always provide better fits to the observed values than either generic models (such as the CRIM model), or fits to other data sets (such as the Topp formula, which was derived for soils). The Topp model consistently underestimates the dielectric constant, while the CRIM model generally overestimates it at both 75 and 1000 MHz. The overall regression procedures can be applied to data from other sites, and potentially used as the basis of inversion of petrophysical properties from measurements of electric and dielectric properties

  7. Depositional cyclicity and scaling petrophysical parameters for characterization of fluid flow in carbonate platform reservoirs: San Andres outcrop, Algerita escarpment, New Mexico

    SciTech Connect

    Lucia, F.J.; Kerans, C.; Senger, R.K. )

    1992-04-01

    San Andres outcrops along the Algerita escarpment in the Guadalupe Mountains of New Mexico are composed of five sequences: a lower to middle San Andres sequence and four upper San Andres sequences. Within a sequence the predictable stacking patterns of cycles in different systems tracts, and of facies and rock-fabric successions within cycles, provide the necessary geologic framework for petrophysical quantification of geologic models. Rock fabric is a fundamental scale controlling the petrophysical properties of porosity, permeability, and capillarity. Four basic rock fabrics are present in the upper San Andres at Lawyer Canyon: dolograinstone, dolograin-dominated packstone, finely crystalline mud-dominated dolostone, and separate-vug dolograinstone. These four rock fabrics have unique average permeability values and porosity-permeability transforms. Permeability distribution was determined in the grainstone facies of cycle 1 at scales ranging from 1 in. to 100 ft. Variogram analysis of spatial permeability distribution indicates short-range correlation with a relatively high nugget, suggesting that permeability heterogeneity is largely random within a rock-fabric facies. A detailed cross section showing the nine cycles and the vertical and lateral distribution of rock fabrics within the cycles was converted to a permeability flow model using geometric mean permeabilities. The resulting rock-fabric flow model is suitable for input into reservoir simulators for performance prediction studies.

  8. Multivariate distributions of soil hydraulic parameters

    NASA Astrophysics Data System (ADS)

    Qu, Wei; Pachepsky, Yakov; Huisman, Johan Alexander; Martinez, Gonzalo; Bogena, Heye; Vereecken, Harry

    2014-05-01

    Statistical distributions of soil hydraulic parameters have to be known when synthetic fields of soil hydraulic properties need to be generated in ensemble modeling of soil water dynamics and soil water content data assimilation. Pedotransfer functions that provide statistical distributions of water retention and hydraulic conductivity parameters for textural classes are most often used in the parameter field generation. Presence of strong correlations can substantially influence the parameter generation results. The objective of this work was to review and evaluate available data on correlations between van Genuchten-Mualem (VGM) model parameters. So far, two different approaches were developed to estimate these correlations. The first approach uses pedotransfer functions to generate VGM parameters for a large number of soil compositions within a textural class, and then computes parameter correlations for each of the textural classes. The second approach computes the VGM parameter correlations directly from parameter values obtained by fitting VGM model to measured water retention and hydraulic conductivity data for soil samples belonging to a textural class. Carsel and Parish (1988) used the Rawls et al. (1982) pedotransfer functions, and Meyer et al. (1997) used the Rosetta pedotransfer algorithms (Schaap, 2002) to develop correlations according to the first approach. We used the UNSODA database (Nemes et al. 2001), the US Southern Plains database (Timlin et al., 1999), and the Belgian database (Vereecken et al., 1989, 1990) to apply the second approach. A substantial number of considerable (>0.7) correlation coefficients were found. Large differences were encountered between parameter correlations obtained with different approaches and different databases for the same textural classes. The first of the two approaches resulted in generally higher values of correlation coefficients between VGM parameters. However, results of the first approach application depend

  9. Joint estimation of soil moisture profile and hydraulic parameters by ground-penetrating radar data assimilation with maximum likelihood ensemble filter

    NASA Astrophysics Data System (ADS)

    Tran, Anh Phuong; Vanclooster, Marnik; Zupanski, Milija; Lambot, Sébastien

    2014-04-01

    Ground-Penetrating Radar (GPR) has recently become a powerful geophysical technique to characterize soil moisture at the field scale. We developed a data assimilation scheme to simultaneously estimate the vertical soil moisture profile and hydraulic parameters from time-lapse GPR measurements. The assimilation scheme includes a soil hydrodynamic model to simulate the soil moisture dynamics, a full-wave electromagnetic wave propagation model, and petrophysical relationship to link the state variable with the GPR data and a maximum likelihood ensemble assimilation algorithm. The hydraulic parameters are estimated jointly with the soil moisture using a state augmentation technique. The approach allows for the direct assimilation of GPR data, thus maximizing the use of the information. The proposed approach was validated by numerical experiments assuming wrong initial conditions and hydraulic parameters. The synthetic soil moisture profiles were generated by the Hydrus-1D model, which then were used by the electromagnetic model and petrophysical relationship to create "observed" GPR data. The results show that the data assimilation significantly improves the accuracy of the hydrodynamic model prediction. Compared with the surface soil moisture assimilation, the GPR data assimilation better estimates the soil moisture profile and hydraulic parameters. The results also show that the estimated soil moisture profile in the loamy sand and silt soils converge to the "true" state more rapidly than in the clay one. Of the three unknown parameters of the Mualem-van Genuchten model, the estimation of n is more accurate than that of α and Ks. The approach shows a great promise to use GPR measurements for the soil moisture profile and hydraulic parameter estimation at the field scale.

  10. Classifying rock lithofacies using petrophysical data

    NASA Astrophysics Data System (ADS)

    Al-Omair, Osamah; Garrouch, Ali A.

    2010-09-01

    This study automates a type-curve technique for estimating the rock pore-geometric factor (λ) from capillary pressure measurements. The pore-geometric factor is determined by matching the actual rock capillary pressure versus wetting-phase saturation (Pc-Sw) profile with that obtained from the Brooks and Corey model (1966 J. Irrigation Drainage Proc. Am. Soc. Civ. Eng. 61-88). The pore-geometric factor values are validated by comparing the actual measured rock permeability to the permeability values estimated using the Wyllie and Gardner model (1958 World Oil (April issue) 210-28). Petrophysical data for both carbonate and sandstone rocks, along with the pore-geometric factor derived from the type-curve matching, are used in a discriminant analysis for the purpose of developing a model for rock typing. The petrophysical parameters include rock porosity (phi), irreducible water saturation (Swi), permeability (k), the threshold capillary-entry-pressure (Pd), a pore-shape factor (β), and a flow-impedance parameter (n) which is a property that reflects the flow impedance caused by the irreducible wetting-phase saturation. The results of the discriminant analysis indicate that five of the parameters (phi, k, Pd, λ and n) are sufficient for classifying rocks according to two broad lithology classes: sandstones and carbonates. The analysis reveals the existence of a significant discriminant function that is mostly sensitive to the pore-geometric factor values (λ). A discriminant-analysis classification model that honours both static and dynamic petrophysical rock properties is, therefore, introduced. When tested on two distinct data sets, the discriminant-analysis model was able to predict the correct lithofacies for approximately 95% of the tested samples. A comprehensive database of the experimentally collected petrophysical properties of 215 carbonate and sandstone rocks is provided with this study.

  11. Analysing petrophysical parameters of reservoir rock from the Ketzin pilot site (Germany) during long-term CO2-exposure experiments under thermodynamic conditions relevant for the geological storage of CO2

    NASA Astrophysics Data System (ADS)

    Zemke, K.; Fischer, S.; Liebscher, A.; Ketzin Team

    2012-04-01

    In the present study, 7 reservoir core samples from observation well Ktzi 202 at the Ketzin pilot storage site (Germany) were experimentally exposed to pure CO2 and synthetic reservoir brine at simulated reservoir conditions of 5.5 MPa and 40°C. Reservoir rocks are immature arcosic to litharenitic sandstones of the Upper Triassic Stuttgart Formation. After 15, 21, 24, and 40 months, respectively, autoclaves were opened and rock samples were taken for petrophysical characterisation and mineralogical and microbial analyses. Brine samples were analysed with respect to organic and inorganic components. Porosity and pore radii distribution have been investigated before and after the experiments by NMR relaxation and mercury injection. NMR measurements on brine-saturated rock core plugs potentially yield valuable information on the porous structure of the rock core. The distribution of NMR-T2 values (CPMG) reflects pore sizes within the rock core. NMR pore size is a derivative of the ratio pore surface to pore volume. The pore size derived by mercury injection is an area-equivalent diameter of throats connecting the pore system. Both methods produce petrophysical parameters required for calculating storage capacity and hydraulic properties (e.g. injectivity). Measured porosity data of the experimentally treated samples together with data from additional, untreated core samples from the Ketzin wells were also compared with results from wireline porosity determinations in the wells. Based on the NMR measurements, the permeability was calculated with standard parameters for sandstones after Timur-Coates. Mercury injection data was used to calculate sandstone permeabilities after Swanson (1981) and to furthermore determine the threshold pressure. NMR and mercury injection data generally indicate increased porosities and a shift to larger pore sizes during the first months. This suggests mineral dissolution during the experiments in agreement with the observed chemical

  12. Relationship between the erosion properties of soils and other parameters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil parameters are essential for erosion process prediction and ultimately improved model development, especially as they relate to dam and levee failure. Soil parameters including soil texture and structure, soil classification, soil compaction, moisture content, and degree of saturation can play...

  13. Petrophysical evaluation of subterranean formations

    DOEpatents

    Klein, James D; Schoderbek, David A; Mailloux, Jason M

    2013-05-28

    Methods and systems are provided for evaluating petrophysical properties of subterranean formations and comprehensively evaluating hydrate presence through a combination of computer-implemented log modeling and analysis. Certain embodiments include the steps of running a number of logging tools in a wellbore to obtain a variety of wellbore data and logs, and evaluating and modeling the log data to ascertain various petrophysical properties. Examples of suitable logging techniques that may be used in combination with the present invention include, but are not limited to, sonic logs, electrical resistivity logs, gamma ray logs, neutron porosity logs, density logs, NRM logs, or any combination or subset thereof.

  14. NMR Relaxation and Petrophysical Properties

    NASA Astrophysics Data System (ADS)

    Fleury, Marc

    2011-03-01

    NMR relaxation is routinely used in the field of geosciences to give basic petrophysical properties such as porosity, pore size distribution, saturation etc. In this tutorial, we focus on the pore size distribution deduced from NMR. We recall the basic principle used in the interpretation of the NMR signal and compare the results with other standard petrophysical techniques such as mercury pore size distribution, BET specific surface measurements, thin section visualizations. The NMR pore size distribution is a unique information available on water saturated porous media and can give similar results as MICP in certain situations. The scaling of NMR relaxation time distribution (s) into pore sizes (μm) requires the knowledge of the surface relaxivity (μm/s) and we recommend using specific surface measurements as an independent determination of solid surface areas. With usual surface relaxivities, the NMR technique can explore length-scales starting from nano-meters and ending around 100 μm. Finally, we will introduce briefly recent techniques sensitive to the pore to pore diffusional exchange, providing new information on the connectivity of the pore network, but showing another possibility of discrepancy in the determination of pore size distribution with standard techniques.

  15. Optimizing Soil Hydraulic Parameters in RZWQM2 Under Fallow Conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effective estimation of soil hydraulic parameters is essential for predicting soil water dynamics and related biochemical processes in agricultural systems. However, high uncertainties in estimated parameter values limit a model’s skill for prediction and application. In this study, a global search ...

  16. Dynamics of soil parameters relevant for humanitarian demining

    NASA Astrophysics Data System (ADS)

    Obhođaš, Jasmina; Vdović, Neda; Valković, Vlado

    2005-12-01

    In this paper we analyzed characteristics of 6 different soils from the test field at the Ruđer Bošković Institute. Many soil properties relevant for the performance of humanitarian demining tools strongly depend on water content. This is an effort to understand better the soil moisture variability and to find soil parameters that can predict the water content regarding the weather conditions. Such knowledge will allow to optimize demining operations. To gather the main parameters like field capacity, rate and delay of water infiltration and soil water retention which are all related to soil texture, daily time-series of soil moisture from August to November 2001, where analyzed.

  17. The relationship between water content and swelling parameters of soils

    NASA Astrophysics Data System (ADS)

    Samet Öngen, Ali; Abiddin Ergüler, Zeynal

    2016-04-01

    The level of swelling dependent damages of low-rising engineering structures constructed on and/or in unsaturated zone of soil deposits is generally controlled by mineralogical compositions and water content of soils. It is well known that seasonal or even daily variations in water content causes volumetric changes within unsaturated zone of a soil composed mainly of swelling type clay minerals. In this regard, in addition to mineralogical composition of soils, water content should be considered as another major factor for understanding swelling behavior of soils. It can be concluded from literature review that swelling parameters of soils were determined by performing experimental studies on dry samples or samples having natural water content without incorporating seasonal continuous variations in water content. Thus, the effect of variation in water content on swelling mechanism of soils is not yet sufficiently studied in previous studies. For achieving accurate understanding of swelling behavior at field conditions, a new approach is required to identify swelling parameter at different initial water content. For this purpose, a comprehensive study was performed to investigate the effect of water content on swelling behavior of soils and to find a new parameter for assessing swelling parameters of samples prepared at different initial water content conditions. Based on main objectives of this study, soil samples having wide range in terms of grain size distributions, mineralogical compositions and Atterberg limits were collected from different locations in Turkey. To minimize the effect of dry unit weight on swelling behavior of soils, samples were prepared at the same dry unit weight (14.6 kN/m3) and different initial water contents. It was determined that there is a linear relationship between initial water content and swelling parameters, and swelling parameters decrease with increasing initial water content conditions. By utilizing this relationship, a new

  18. Identification of optimal soil hydraulic functions and parameters for predicting soil moisture

    EPA Science Inventory

    We examined the accuracy of several commonly used soil hydraulic functions and associated parameters for predicting observed soil moisture data. We used six combined methods formed by three commonly used soil hydraulic functions – i.e., Brooks and Corey (1964) (BC), Campbell (19...

  19. Uncertainty in dual permeability model parameters for structured soils

    PubMed Central

    Arora, B.; Mohanty, B. P.; McGuire, J. T.

    2013-01-01

    Successful application of dual permeability models (DPM) to predict contaminant transport is contingent upon measured or inversely estimated soil hydraulic and solute transport parameters. The difficulty in unique identification of parameters for the additional macropore- and matrix-macropore interface regions, and knowledge about requisite experimental data for DPM has not been resolved to date. Therefore, this study quantifies uncertainty in dual permeability model parameters of experimental soil columns with different macropore distributions (single macropore, and low- and high-density multiple macropores). Uncertainty evaluation is conducted using adaptive Markov chain Monte Carlo (AMCMC) and conventional Metropolis-Hastings (MH) algorithms while assuming 10 out of 17 parameters to be uncertain or random. Results indicate that AMCMC resolves parameter correlations and exhibits fast convergence for all DPM parameters while MH displays large posterior correlations for various parameters. This study demonstrates that the choice of parameter sampling algorithms is paramount in obtaining unique DPM parameters when information on covariance structure is lacking, or else additional information on parameter correlations must be supplied to resolve the problem of equifinality of DPM parameters. This study also highlights the placement and significance of matrix-macropore interface in flow experiments of soil columns with different macropore densities. Histograms for certain soil hydraulic parameters display tri-modal characteristics implying that macropores are drained first followed by the interface region and then by pores of the matrix domain in drainage experiments. Results indicate that hydraulic properties and behavior of the matrix-macropore interface is not only a function of saturated hydraulic conductivity of the macroporematrix interface (Ksa) and macropore tortuosity (lf) but also of other parameters of the matrix and macropore domains. PMID:24478531

  20. Estimating soil hydraulic parameters from transient flow experiments in a centrifuge using parameter optimization technique

    USGS Publications Warehouse

    Simunek, J.; Nimmo, J.R.

    2005-01-01

    A modified version of the Hydrus software package that can directly or inversely simulate water flow in a transient centrifugal field is presented. The inverse solver for parameter estimation of the soil hydraulic parameters is then applied to multirotation transient flow experiments in a centrifuge. Using time-variable water contents measured at a sequence of several rotation speeds, soil hydraulic properties were successfully estimated by numerical inversion of transient experiments. The inverse method was then evaluated by comparing estimated soil hydraulic properties with those determined independently using an equilibrium analysis. The optimized soil hydraulic properties compared well with those determined using equilibrium analysis and steady state experiment. Multirotation experiments in a centrifuge not only offer significant time savings by accelerating time but also provide significantly more information for the parameter estimation procedure compared to multistep outflow experiments in a gravitational field. Copyright 2005 by the American Geophysical Union.

  1. Rock Mechanical Properties from Logs Petrophysics : Concepts and Results

    NASA Astrophysics Data System (ADS)

    Gaillot, Philippe; Crawford, Brian; Alramahi, Bashar; Karner, Steve

    2010-05-01

    The objective of the "geomechanics from logs" (GML) research project is to develop model-driven predictive software for determining rock mechanical properties (specifically rock strength, compressibility and fracability) from other, more easily measured, rock properties (e.g. lithology, porosity, clay volume, velocity) routinely derived from nuclear, resistivity and acoustic logging tools. To this end, geomechanics from logs seeks to increase fundamental understanding of the primary geologic controls on rock mechanical properties and to translate this new insight into novel predictive tools. In detail, GML predictors rely on (i) the generation of relational rock mechanical properties databases incorporating QC'd core-based laboratory measurements (both in-house and high-precision published data); (ii) the use of established rock physics models (e.g. friable sand, contact cement models) to investigate theoretical relationships between geologic processes, reservoir environment, rock microstructure and elastic, bulk and transport petrophysical attributes/properties; (iii) the subdivision of database rocks into generic lithotypes (e.g. sand, shaly sand, sandy shale, shale) with common petrophysical attributes/properties; (iv) the use of multivariate statistics to generate lithotype-dependent empirical predictive relationships between mechanical properties and log-derived petrophysical attributes/properties; (v) the estimation of uncertainties associated with predictive function parameters; (vi) the application and validation of mechanical properties predictive tools to well-documented case studies (e.g. sand strength for perforation stability, rock compressibility for reservoir simulation) to test overall performance and quantify uncertainty in predictions. This paper presents the results of various rock strength, rock compressibility and rock fracability case studies conducted in wells of different stratigraphic age and depositional environment. Overall, GML (i

  2. Integrating microbial diversity in soil carbon dynamic models parameters

    NASA Astrophysics Data System (ADS)

    Louis, Benjamin; Menasseri-Aubry, Safya; Leterme, Philippe; Maron, Pierre-Alain; Viaud, Valérie

    2015-04-01

    Faced with the numerous concerns about soil carbon dynamic, a large quantity of carbon dynamic models has been developed during the last century. These models are mainly in the form of deterministic compartment models with carbon fluxes between compartments represented by ordinary differential equations. Nowadays, lots of them consider the microbial biomass as a compartment of the soil organic matter (carbon quantity). But the amount of microbial carbon is rarely used in the differential equations of the models as a limiting factor. Additionally, microbial diversity and community composition are mostly missing, although last advances in soil microbial analytical methods during the two past decades have shown that these characteristics play also a significant role in soil carbon dynamic. As soil microorganisms are essential drivers of soil carbon dynamic, the question about explicitly integrating their role have become a key issue in soil carbon dynamic models development. Some interesting attempts can be found and are dominated by the incorporation of several compartments of different groups of microbial biomass in terms of functional traits and/or biogeochemical compositions to integrate microbial diversity. However, these models are basically heuristic models in the sense that they are used to test hypotheses through simulations. They have rarely been confronted to real data and thus cannot be used to predict realistic situations. The objective of this work was to empirically integrate microbial diversity in a simple model of carbon dynamic through statistical modelling of the model parameters. This work is based on available experimental results coming from a French National Research Agency program called DIMIMOS. Briefly, 13C-labelled wheat residue has been incorporated into soils with different pedological characteristics and land use history. Then, the soils have been incubated during 104 days and labelled and non-labelled CO2 fluxes have been measured at ten

  3. Hysteresis and uncertainty in soil water-retention curve parameters

    USGS Publications Warehouse

    Likos, William J.; Lu, Ning; Godt, Jonathan W.

    2014-01-01

    Accurate estimates of soil hydraulic parameters representing wetting and drying paths are required for predicting hydraulic and mechanical responses in a large number of applications. A comprehensive suite of laboratory experiments was conducted to measure hysteretic soil-water characteristic curves (SWCCs) representing a wide range of soil types. Results were used to quantitatively assess differences and uncertainty in three simplifications frequently adopted to estimate wetting-path SWCC parameters from more easily measured drying curves. They are the following: (1) αw=2αd, (2) nw=nd, and (3) θws=θds, where α, n, and θs are fitting parameters entering van Genuchten’s commonly adopted SWCC model, and the superscripts w and d indicate wetting and drying paths, respectively. The average ratio αw/αd for the data set was 2.24±1.25. Nominally cohesive soils had a lower αw/αd ratio (1.73±0.94) than nominally cohesionless soils (3.14±1.27). The average nw/nd ratio was 1.01±0.11 with no significant dependency on soil type, thus confirming the nw=nd simplification for a wider range of soil types than previously available. Water content at zero suction during wetting (θws) was consistently less than during drying (θds) owing to air entrapment. The θws/θds ratio averaged 0.85±0.10 and was comparable for nominally cohesive (0.87±0.11) and cohesionless (0.81±0.08) soils. Regression statistics are provided to quantitatively account for uncertainty in estimating hysteretic retention curves. Practical consequences are demonstrated for two case studies.

  4. Soil transport parameters of potassium under a tropical saline soil condition using STANMOD

    NASA Astrophysics Data System (ADS)

    Suzanye da Silva Santos, Rafaelly; Honorio de Miranda, Jarbas; Previatello da Silva, Livia

    2015-04-01

    Environmental responsibility and concerning about the final destination of solutes in soil, so more studies allow a better understanding about the solutes behaviour in soil. Potassium is a macronutrient that is required in high concentrations, been an extremely important nutrient for all agricultural crops. It plays essential roles in physiological processes vital for plant growth, from protein synthesis to maintenance of plant water balance, and is available to plants dissolved in soil water while exchangeable K is loosely held on the exchange sites on the surface of clay particles. K will tend to be adsorbed onto the surface of negatively charged soil particles. Potassium uptake is vital for plant growth but in saline soils sodium competes with potassium for uptake across the plasma membrane of plant cells. This can result in high Na+:K+ ratios that reduce plant growth and eventually become toxic. This study aimed to obtain soil transport parameters of potassium in saline soil, such as: pore water velocity in soil (v), retardation factor (R), dispersivity (λ) and dispersion coefficient (D), in a disturbed sandy soil with different concentrations of potassium chlorate solution (KCl), which is one of the most common form of potassium fertilizer. The experiment was carried out using soil samples collected in a depth of 0 to 20 cm, applying potassium chlorate solution containing 28.6, 100, 200 and 500 mg L-1 of K. To obtain transport parameters, the data were adjusted with the software STANMOD. At low concentrations, interaction between potassium and soil occur more efficiently. It was observed that only the breakthrough curve prepared with solution of 500 mg L-1 reached the applied concentration, and the solution of 28.6 mg L-1 overestimated the parameters values. The STANMOD proved to be efficient in obtaining potassium transport parameters; KCl solution to be applied should be greater than 500 mg L-1; solutions with low concentrations tend to overestimate

  5. Spatial variability of soil parameters - subsoils as heterogenic environments

    NASA Astrophysics Data System (ADS)

    Heinze, Stefanie; John, Stephan; Kirfel, Kristina; Mikutta, Robert; Niebuhr, Jana; Preusser, Sebastian; Marschner, Bernd

    2014-05-01

    Subsoils are known to store a high amount of organic carbon (40-60% of the total C-pool). 14C-dating detected that in subsoils organic matter (OM) age increased with increasing depth and reaches several 1000 years. The high age of subsoil OM might be caused by a complex structure, by limited access of OM for microbial decomposition or a limited input of fresh organic material. The latter, mostly reaches the subsoil through special pathways, like root channels, bioturbation processes or preferential flow pathways where dissolved organic carbon will be transported. The spatially concentrated input of OM supposed that the heterogeneity of physical, chemical, and biological soil parameters is higher in subsoils than in top soils. Within the DFG-FOR 1806 we investigated the heterogeneity of soil parameters in soil profiles (top and subsoil) of a podzolic Cambisol in a 95 years old beech forest in Lower Saxony, Germany. Three transects were established with a vertical and horizontal dimension of 2.00m and 3.15m, respectively. 64 soil samples were taken out of a grid in 10, 35, 60, 85, 110, 135, 160 and 185m depth with increasing horizontal distance to a main tree. To analyze the variability and relationship of soil properties in the soil profiles, analysis of soil physical (e.g. texture), chemical (e.g. organic C, dissolved organic C, total N, pH), and biological (e.g. enzyme activities, microbial biomass C) parameters were conducted within the research group. The results showed a very strong decline of organic C from 1.15% (10cm) to 0.12% (60cm). The differences of SOC were not pronounced with increasing distance to the main tree. Also total nitrogen decreased between 10 and 60cm strongly from 0.05 to 0.005%. The pH showed a slight increase between 10 and 35cm from 3.51 up to 4.27. For microbial biomass measures the same stratification was detected but the variance within biological parameters were higher in the subsoil than in the topsoil. Enzyme activities showed a

  6. Soil air CO2 concentration as an integrative parameter of soil structure

    NASA Astrophysics Data System (ADS)

    Ebeling, Corinna; Gaertig, Thorsten; Fründ, Heinz-Christian

    2015-04-01

    The assessment of soil structure is an important but difficult issue and normally takes place in the laboratory. Typical parameters are soil bulk density, porosity, water or air conductivity or gas diffusivity. All methods are time-consuming. The integrative parameter soil air CO2 concentration ([CO2]) can be used to assess soil structure in situ and in a short time. Several studies highlighted that independent of soil respiration, [CO2] in the soil air increases with decreasing soil aeration. Therefore, [CO2] is a useful indicator of soil aeration. Embedded in the German research project RÜWOLA, which focus on soil protection at forest sites, we investigated soil compaction and recovery of soil structure after harvesting. Therefore, we measured soil air CO2 concentrations continuously and in single measurements and compared the results with the measurements of bulk density, porosity and gas diffusivity. Two test areas were investigated: At test area 1 with high natural regeneration potential (clay content approx. 25 % and soil-pH between 5 and 7), solid-state CO2-sensors using NDIR technology were installed in the wheel track of different aged skidding tracks in 5 and 10 cm soil depths. At area 2 (acidic silty loam, soil-pH between 3.5 and 4), CO2-sensors and water-tension sensors (WatermarkR) were installed in 6 cm soil depth. The results show a low variance of [CO2] in the undisturbed soil with a long term mean from May to June 2014 between 0.2 and 0.5 % [CO2] in both areas. In the wheel tracks [CO2] was consistently higher. The long term mean [CO2] in the 8-year-old-wheel track in test area 1 is 5 times higher than in the reference soil and shows a high variation (mean=2.0 %). The 18-year-old wheel track shows a long-term mean of 1.2 % [CO2]. Furthermore, there were strong fluctuations of [CO2] in the wheel tracks corresponding to precipitation and humidity. Similar results were yielded with single measurements during the vegetation period using a portable

  7. Evaluation of polarimetric SAR parameters for soil moisture retrieval

    NASA Technical Reports Server (NTRS)

    Shi, Jian-Cheng; Vanzyl, Jakob J.; Engman, Edwin T.

    1992-01-01

    Results of ongoing efforts to develop an algorithm for soil moisture retrieval from Synthetic Aperture Radar (SAR) imagery are reported. Estimates of soil moisture are of great importance in numerous environmental studies, including hydrology, meteorology, and agriculture. Previous studies using extensive scatterometer measurements have established the optimum parameters for moisture retrieval as C-band HH radar operating at incidence angles between 10 to 15 deg. However, these parameters were not tested or verified with imaging radar systems. The results from different investigators showed considerable variability in the relationship between soil moisture and radar backscattering. This variability suggests that those algorithms are site-specific. Furthermore, the small incidence angle requirement limits the spatial application, especially for airborne radar systems.

  8. Geotechnical Parameters of Alluvial Soils from in-situ Tests

    NASA Astrophysics Data System (ADS)

    Młynarek, Zbigniew; Stefaniak, Katarzyna; Wierzbicki, Jędrzej

    2012-10-01

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

  9. Geotechnical Parameters of Alluvial Soils from in-situ Tests

    NASA Astrophysics Data System (ADS)

    Młynarek, Zbigniew; Stefaniak, Katarzyna; Wierzbicki, Jedrzej

    2012-10-01

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

  10. Spatial Prediction of Soil Classes by Using Soil Weathering Parameters Derived from vis-NIR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Ramirez-Lopez, Leonardo; Alexandre Dematte, Jose

    2010-05-01

    There is consensus in the scientific community about the great need of spatial soil information. Conventional mapping methods are time consuming and involve high costs. Digital soil mapping has emerged as an area in which the soil mapping is optimized by the application of mathematical and statistical approaches, as well as the application of expert knowledge in pedology. In this sense, the objective of the study was to develop a methodology for the spatial prediction of soil classes by using soil spectroscopy methodologies related with fieldwork, spectral data from satellite image and terrain attributes in simultaneous. The studied area is located in São Paulo State, and comprised an area of 473 ha, which was covered by a regular grid (100 x 100 m). In each grid node was collected soil samples at two depths (layers A and B). There were extracted 206 samples from transect sections and submitted to soil analysis (clay, Al2O3, Fe2O3, SiO2 TiO2, and weathering index). The first analog soil class map (ASC-N) contains only soil information regarding from orders to subgroups of the USDA Soil Taxonomy System. The second (ASC-H) map contains some additional information related to some soil attributes like color, ferric levels and base sum. For the elaboration of the digital soil maps the data was divided into three groups: i) Predicted soil attributes of the layer B (related to the soil weathering) which were obtained by using a local soil spectral library; ii) Spectral bands data extracted from a Landsat image; and iii) Terrain parameters. This information was summarized by a principal component analysis (PCA) in each group. Digital soil maps were generated by supervised classification using a maximum likelihood method. The trainee information for this classification was extracted from five toposequences based on the analog soil class maps. The spectral models of weathering soil attributes shown a high predictive performance with low error (R2 0.71 to 0.90). The spatial

  11. Soil-related Input Parameters for the Biosphere Model

    SciTech Connect

    A. J. Smith

    2003-07-02

    This analysis is one of the technical reports containing documentation of the Environmental Radiation Model for Yucca Mountain Nevada (ERMYN), a biosphere model supporting the Total System Performance Assessment (TSPA) for the geologic repository at Yucca Mountain. The biosphere model is one of a series of process models supporting the Total System Performance Assessment (TSPA) for the Yucca Mountain repository. A graphical representation of the documentation hierarchy for the ERMYN biosphere model is presented in Figure 1-1. This figure shows the interrelationships among the products (i.e., analysis and model reports) developed for biosphere modeling, and the plan for development of the biosphere abstraction products for TSPA, as identified in the ''Technical Work Plan: for Biosphere Modeling and Expert Support'' (BSC 2003 [163602]). It should be noted that some documents identified in Figure 1-1 may be under development at the time this report is issued and therefore not available. This figure is included to provide an understanding of how this analysis report contributes to biosphere modeling in support of the license application, and is not intended to imply that access to the listed documents is required to understand the contents of this report. This report, ''Soil Related Input Parameters for the Biosphere Model'', is one of the five analysis reports that develop input parameters for use in the ERMYN model. This report is the source documentation for the six biosphere parameters identified in Table 1-1. ''The Biosphere Model Report'' (BSC 2003 [160699]) describes in detail the conceptual model as well as the mathematical model and its input parameters. The purpose of this analysis was to develop the biosphere model parameters needed to evaluate doses from pathways associated with the accumulation and depletion of radionuclides in the soil. These parameters support the calculation of radionuclide concentrations in soil from on-going irrigation and ash

  12. Long-term effects of deep soil loosening on root distribution and soil physical parameters in compacted lignite mine soils

    NASA Astrophysics Data System (ADS)

    Badorreck, Annika; Krümmelbein, Julia; Raab, Thomas

    2015-04-01

    Soil compaction is a major problem of soils on dumped mining substrates in Lusatia, Germany. Deep ripping and cultivation of deep rooting plant species are considered to be effective ways of agricultural recultivation. Six years after experiment start, we studied the effect of initial deep soil loosening (i.e. down to 65 cm) on root systems of rye (Secale cereale) and alfalfa (Medicago sativa) and on soil physical parameters. We conducted a soil monolith sampling for each treatment (deep loosened and unloosened) and for each plant species (in three replicates, respectively) to determine root diameter, length density and dry mass as well as soil bulk density. Further soil physical analysis comprised water retention, hydraulic conductivity and texture in three depths. The results showed different reactions of the root systems of rye and alfalfa six years after deep ripping. In the loosened soil the root biomass of the rye was lower in depths of 20-40 cm and the root biomass of alfalfa was also decreased in depths of 20-50 cm together with a lower root diameter for both plant species. Moreover, total and fine root length density was higher for alfalfa and vice versa for rye. The soil physical parameters such as bulk density showed fewer differences, despite a higher bulk density in 30-40cm for the deep loosened rye plot which indicates a more pronounced plough pan.

  13. Establishing principal soil quality parameters influencing earthworms in urban soils using bioassays.

    PubMed

    Hankard, Peter K; Bundy, Jacob G; Spurgeon, David J; Weeks, Jason M; Wright, Julian; Weinberg, Claire; Svendsen, Claus

    2005-01-01

    Potential contamination at ex-industrial sites means that, prior to change of use, it will be necessary to quantify the extent of risks to potential receptors. To assess ecological hazards, it is often suggested to use biological assessment to augment chemical analyses. Here we investigate the potential of a commonly recommended bioassay, the earthworm reproduction test, to assess the status of urban contaminated soils. Sample points at all study sites had contaminant concentrations above the Dutch soil criteria Target Values. In some cases, the relevant Intervention Values were exceeded. Earthworm survival at most points was high, but reproduction differed significantly in soil from separate patches on the same site. When the interrelationships between soil parameters and reproduction were studied, it was not possible to create a good model of site soil toxicity based on single or even multiple chemical measurements of the soils. We thus conclude that chemical analysis alone is not sufficient to characterize soil quality and confirms the value of biological assays for risk assessment of potentially contaminated soils. PMID:15519451

  14. Estimation of field-scale soil hydraulic and dielectric parametersthrough joint inversion of GPR and hydrological data

    SciTech Connect

    Kowalsky, Michael B.; Finsterle, Stefan; Peterson, John; Hubbard,Susan; Rubin, Yoram; Majer, Ernest; Ward, Andy; Gee, Glendon

    2005-05-05

    A method is described for jointly using time-lapse multiple-offset cross-borehole ground-penetrating radar (GPR) travel time measurements and hydrological measurements to estimate field-scale soil hydraulic parameters and parameters of the petrophysical function, which relates soil porosity and water saturation to the effective dielectric constant. We build upon previous work to take advantage of a wide range of GPR data acquisition configurations and to accommodate uncertainty in the petrophysical function. Within the context of water injection experiments in the vadose zone, we test our inversion methodology with synthetic examples and apply it to field data. The synthetic examples show that while realistic errors in the petrophysical function cause substantial errors in the soil hydraulic parameter estimates,simultaneously estimating petrophysical parameters allows for these errors to be minimized. Additionally, we observe in some cases that inaccuracy in the GPR simulator causes systematic error in simulated travel times, making necessary the simultaneous estimation of a correction parameter. We also apply the method to a three-dimensional field setting using time-lapse GPR and neutron probe (NP) data sets collected during an infiltration experiment at the U.S. Department of Energy (DOE) Hanford site in Washington. We find that inclusion of GPR data in the inversion procedure allows for improved predictions of water content, compared to predictions made using NP data alone.

  15. Improving the relationship between soil characteristics and metal bioavailability by using reactive fractions of soil parameters in calcareous soils.

    PubMed

    de Santiago-Martín, Ana; van Oort, Folkert; González, Concepción; Quintana, José R; Lafuente, Antonio L; Lamy, Isabelle

    2015-01-01

    The contribution of the nature instead of the total content of soil parameters relevant to metal bioavailability in lettuce was tested using a series of low-polluted Mediterranean agricultural calcareous soils offering natural gradients in the content and composition of carbonate, organic, and oxide fractions. Two datasets were compared by canonical ordination based on redundancy analysis: total concentrations (TC dataset) of main soil parameters (constituents, phases, or elements) involved in metal retention and bioavailability; and chemically defined reactive fractions of these parameters (RF dataset). The metal bioavailability patterns were satisfactorily explained only when the RF dataset was used, and the results showed that the proportion of crystalline Fe oxides, dissolved organic C, diethylene-triamine-pentaacetic acid (DTPA)-extractable Cu and Zn, and a labile organic pool accounted for 76% of the variance. In addition, 2 multipollution scenarios by metal spiking were tested that showed better relationships with the RF dataset than with the TC dataset (up to 17% more) and new reactive fractions involved. For Mediterranean calcareous soils, the use of reactive pools of soil parameters rather than their total contents improved the relationships between soil constituents and metal bioavailability. Such pool determinations should be systematically included in studies dealing with bioavailability or risk assessment. PMID:25318656

  16. Bioremediation treatment of hydrocarbon-contaminated Arctic soils: influencing parameters.

    PubMed

    Naseri, Masoud; Barabadi, Abbas; Barabady, Javad

    2014-10-01

    The Arctic environment is very vulnerable and sensitive to hydrocarbon pollutants. Soil bioremediation is attracting interest as a promising and cost-effective clean-up and soil decontamination technology in the Arctic regions. However, remoteness, lack of appropriate infrastructure, the harsh climatic conditions in the Arctic and some physical and chemical properties of Arctic soils may reduce the performance and limit the application of this technology. Therefore, understanding the weaknesses and bottlenecks in the treatment plans, identifying their associated hazards, and providing precautionary measures are essential to improve the overall efficiency and performance of a bioremediation strategy. The aim of this paper is to review the bioremediation techniques and strategies using microorganisms for treatment of hydrocarbon-contaminated Arctic soils. It takes account of Arctic operational conditions and discusses the factors influencing the performance of a bioremediation treatment plan. Preliminary hazard analysis is used as a technique to identify and assess the hazards that threaten the reliability and maintainability of a bioremediation treatment technology. Some key parameters with regard to the feasibility of the suggested preventive/corrective measures are described as well. PMID:24903252

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  18. Soil-Related Input Parameters for the Biosphere Model

    SciTech Connect

    A. J. Smith

    2004-09-09

    This report presents one of the analyses that support the Environmental Radiation Model for Yucca Mountain Nevada (ERMYN). The ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) describes the details of the conceptual model as well as the mathematical model and the required input parameters. The biosphere model is one of a series of process models supporting the postclosure Total System Performance Assessment (TSPA) for the Yucca Mountain repository. A schematic representation of the documentation flow for the Biosphere input to TSPA is presented in Figure 1-1. This figure shows the evolutionary relationships among the products (i.e., analysis and model reports) developed for biosphere modeling, and the biosphere abstraction products for TSPA, as identified in the ''Technical Work Plan for Biosphere Modeling and Expert Support'' (TWP) (BSC 2004 [DIRS 169573]). This figure is included to provide an understanding of how this analysis report contributes to biosphere modeling in support of the license application, and is not intended to imply that access to the listed documents is required to understand the contents of this report. This report, ''Soil-Related Input Parameters for the Biosphere Model'', is one of the five analysis reports that develop input parameters for use in the ERMYN model. This report is the source documentation for the six biosphere parameters identified in Table 1-1. The purpose of this analysis was to develop the biosphere model parameters associated with the accumulation and depletion of radionuclides in the soil. These parameters support the calculation of radionuclide concentrations in soil from on-going irrigation or ash deposition and, as a direct consequence, radionuclide concentration in other environmental media that are affected by radionuclide concentrations in soil. The analysis was performed in accordance with the TWP (BSC 2004 [DIRS 169573]) where the governing procedure was defined as AP-SIII.9Q, ''Scientific Analyses''. This

  19. Within-field variability of plant and soil parameters

    NASA Technical Reports Server (NTRS)

    Ulaby, F. T. (Principal Investigator); Brisco, B.; Dobson, C.

    1981-01-01

    The variability of ground truth data collected for vegetation experiments was investigated. Two fields of wheat and one field of corn were sampled on two different dates. The variability of crop and soil parameters within a field, between two fields of the same type, and within a field over time were compared statistically. The number of samples from each test site required in order to be able to determine with confidence the mean and standard deviations for a given variable was determined. Eight samples were found to be adequate for plant height determinations, while twenty samples were required for plant moisture and soil moisture characterization. Eighteen samples were necessary for detecting within field variability over time and for between field variability for the same crop. The necessary sample sites vary according to the physiological growth stage of the crop and recent weather events that affect the moisture and/or height characteristics of the field in question.

  20. Initial Measurements of Petrophysical Properties on Rocks from the Los Azufres, Mexico, Geothermal Field

    SciTech Connect

    Contreras, E.; Iglesias, E.; Razo, E.

    1986-01-21

    Petrophysical properties of geothermal reservoir rocks are valuable information for many activities, including reservoir characterization, modeling, field test analysis and planning of exploitation techniques. Petrophysical data of rocks from geothermal reservoirs located in volcanic areas is in general very scarce. In particular, no petrophysical data of rocks from the Los Azufres geothermal field area has ever been published. This work presents the results of initial petrophysical studies on outcrop rocks and drill core samples from the Los Azufres geothermal field. These studies are the first part of an ongoing experimental program intended to establish a data-base about physical properties of the Los Azufres rocks, in support of the many reservoir engineering activities which require of such information. The experimental work carried out consisted of laboratory measurements of density, porosity, permeability, compressibility, thermal conductivity, thermal expansion, electrical resistivity and sonic wave velocities. Some of the experiments were aimed at investigation of the effects of temperature, pressure, saturation and other parameters on the physical properties of rocks.

  1. Parameter Estimation for a crop model: separate and joint calibration of soil and plant parameters

    NASA Astrophysics Data System (ADS)

    Hildebrandt, A.; Jackisch, C.; Luis, S.

    2008-12-01

    Vegetation plays a major role both in the atmospheric and terrestrial water cycle. A great deal of vegetation cover in the developed world consists of agricultural used land (i.e. 44 % of the territory of the EU). Therefore, crop models have become increasingly prominent for studying the impact of Global Change both on economic welfare as well as on influence of vegetation on climate, and feedbacks with hydrological processes. By doing so, it is implied that crop models properly reflect the soil water balance and vertical exchange with the atmosphere. Although crop models can be incorporated in Surface Vegetation Atmosphere Transfer Schemes for that purpose, their main focus has traditionally not been on predicting water and energy fluxes, but yield. In this research we use data from two lysimeters in Brandis (Saxony, Germany), which have been planted with the crops of the surrounding farm, to test the capability of the crop model in SWAP. The lysimeters contain different natural soil cores, leading to substantially different yield. This experiment gives the opportunity to test, if the crop model is portable - that is if a calibrated crop can be moved between different locations. When using the default parameters for the respective environment, the model does neither quantitatively nor qualitatively reproduce the difference in yield and LAI for the different lysimeters. The separate calibration of soil and plant parameter was poor compared to the joint calibration of plant and soil parameters. This suggests that the model is not portable, but needs to be calibrated for individual locations, based on measurements or expert knowledge.

  2. Soil hydraulic parameters and surface soil moisture of a tilled bare soil plot inversely derived from l-band brightness temperatures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We coupled a radiative transfer approach with a soil hydrological model (HYDRUS 1D) and a global optimization routine SCE-UA to derive soil hydraulic parameters and soil surface roughness from measured brightness temperatures at 1.4 GHz (L-band) and measured rainfall and calculated potential soil ev...

  3. Petrophysical Properties (Density and Magnetization) of Rocks from the Suhbaatar-Ulaanbaatar-Dalandzadgad Geophysical Profile in Mongolia and Their Implications

    PubMed Central

    Gao, Jintian; Gu, Zuowen; Dagva, Baatarkhuu; Tserenpil, Batsaikhan

    2013-01-01

    Petrophysical properties of 585 rock samples from the Suhbaatar-Ulaanbaatar-Dalandzadgad geophysical profile in Mongolia are presented. Based on the rock classifications and tectonic units, petrophysical parameters (bulk density, magnetic susceptibility, intensity of natural remanent magnetization, and Köenigsberger ratio) of these rocks are summarized. Results indicate that (1) significant density contrast of different rocks would result in variable gravity anomalies along the profile; (2) magnetic susceptibility and natural remanent magnetization of all rocks are variable, covering 5-6 orders of magnitude, which would make a variable induced magnetization and further links to complex magnetic anomalies in ground surface; (3) the distribution of rocks with different lithologies controls the pattern of lithospheric magnetic anomaly along the profile. The petrophysical database thus provides not only one of the keys to understand the geological history and structure of the profile, but also essential information for analysis and interpretation of the geophysical (e.g., magnetic and gravity) survey data. PMID:24324382

  4. Incorporating Soil Hydraulic Parameter Statistics in Developing Pedo-transfer Functions

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Zhu, J.; Ye, M.; Meyer, P. D.; Pan, F.; Hassan, A. E.

    2007-12-01

    In this study, we develop artificial neural network (ANN) based pedotransfer functions (PTFs) to predict soil hydraulic properties. The PTF approach is an efficient way of translating less costly available data, such as particle-size distributions, soil textures and other geophysical measurements, to soil hydraulic parameters required for numerical simulations and other applications. The ANN PTFs need to be trained before being used to transfer indirect measurements to soil hydraulic parameters. The traditional training process, in general, is to adjust ANN's coefficients to solely minimize the difference between the estimated and measured soil hydraulic parameters. The training process, however, did not consider the distributions of soil hydraulic parameters and the trained neural networks may yield improper distributions, which may severely affect probabilistic predictions. We incorporate the distributions of the soil hydraulic parameters into the ANN PTF development. In addition, it has been observed that PTFs can introduce unrealistic correlations between the output parameters. The unwanted artificial correlations need to be penalized during the training process, since it is well known that parameter correlations have significant effect on predictions. We achieve these two goals by adding two regularization terms to the ANN objective functions. A suite of new neural network models are developed to estimate soil hydraulic parameters. These neural network models have the same input and output variables, but different objective functions, which incorporate sequentially the site soil hydraulic parameter measurements, parameter probability distributions, and parameter correlations.

  5. Modeling soil detachment capacity by rill flow using hydraulic parameters

    NASA Astrophysics Data System (ADS)

    Wang, Dongdong; Wang, Zhanli; Shen, Nan; Chen, Hao

    2016-04-01

    The relationship between soil detachment capacity (Dc) by rill flow and hydraulic parameters (e.g., flow velocity, shear stress, unit stream power, stream power, and unit energy) at low flow rates is investigated to establish an accurate experimental model. Experiments are conducted using a 4 × 0.1 m rill hydraulic flume with a constant artificial roughness on the flume bed. The flow rates range from 0.22 × 10-3 m2 s-1 to 0.67 × 10-3 m2 s-1, and the slope gradients vary from 15.8% to 38.4%. Regression analysis indicates that the Dc by rill flow can be predicted using the linear equations of flow velocity, stream power, unit stream power, and unit energy. Dc by rill flow that is fitted to shear stress can be predicted with a power function equation. Predictions based on flow velocity, unit energy, and stream power are powerful, but those based on shear stress, especially on unit stream power, are relatively poor. The prediction based on flow velocity provides the best estimates of Dc by rill flow because of the simplicity and availability of its measurements. Owing to error in measuring flow velocity at low flow rates, the predictive abilities of Dc by rill flow using all hydraulic parameters are relatively lower in this study compared with the results of previous research. The measuring accuracy of experiments for flow velocity should be improved in future research.

  6. Two-dimensional nuclear magnetic resonance petrophysics.

    PubMed

    Sun, Boqin; Dunn, Keh-Jim

    2005-02-01

    Two-dimensional nuclear magnetic resonance (2D NMR) opens a wide area for exploration in petrophysics and has significant impact to petroleum logging technology. When there are multiple fluids with different diffusion coefficients saturated in a porous medium, this information can be extracted and clearly delineated from CPMG measurements of such a system either using regular pulsing sequences or modified two window sequences. The 2D NMR plot with independent variables of T2 relaxation time and diffusion coefficient allows clear separation of oil and water signals in the rocks. This 2D concept can be extended to general studies of fluid-saturated porous media involving other combinations of two or more independent variables, such as chemical shift and T1/T2 relaxation time (reflecting pore size), proton population and diffusion contrast, etc. PMID:15833623

  7. Petrophysical Analysis of Oil Sand in Athabasca

    NASA Astrophysics Data System (ADS)

    cheong, S.; Lee, H.

    2013-12-01

    Oil sands are the major unconventional energy sources which have great reserves in Alberta, Canada. Recovery techniques such as CSS (Cyclic Steam Stimulation) and SAGD (Steam Assisted Gravity Drainage) enabled to develop deeper bitumen about several hundred meter depth. Before applying CSS and SAGD, reservoir heterogeneity of mud barriers or shale breccias should be clarified to establish injection and production wells successfully. We conducted the integrated petro-physical analysis for oil sands deposits in Athabasca by correlating well logs with seismic data. From 33 well logs and 3D seismic, we have made P-wave impedance by recursive inversion. Target formations of our analysis were the top of Wabiskaw member. Using inverted impedance and multi-attributes, porosity volume was derived at a target depth. Porosity of time slice 375 ms ranged 20 ~ 40 % stretching porous sand body from NE to SW direction. Characteristics of porosity distribution may be useful to design optimum oil sands recovery in Athabasca.

  8. Magnetic resonance imaging in laboratory petrophysical core analysis

    NASA Astrophysics Data System (ADS)

    Mitchell, J.; Chandrasekera, T. C.; Holland, D. J.; Gladden, L. F.; Fordham, E. J.

    2013-05-01

    wettability. The history of MRI in petrophysics is reviewed and future directions considered, including advanced data processing techniques such as compressed sensing reconstruction and Bayesian inference analysis of under-sampled data. Although this review focuses on rock core analysis, the techniques described are applicable in a wider context to porous media in general, such as cements, soils, ceramics, and catalytic materials.

  9. Predicting Soil Salinity with Vis–NIR Spectra after Removing the Effects of Soil Moisture Using External Parameter Orthogonalization

    PubMed Central

    Liu, Ya; Pan, Xianzhang; Wang, Changkun; Li, Yanli; Shi, Rongjie

    2015-01-01

    Robust models for predicting soil salinity that use visible and near-infrared (vis–NIR) reflectance spectroscopy are needed to better quantify soil salinity in agricultural fields. Currently available models are not sufficiently robust for variable soil moisture contents. Thus, we used external parameter orthogonalization (EPO), which effectively projects spectra onto the subspace orthogonal to unwanted variation, to remove the variations caused by an external factor, e.g., the influences of soil moisture on spectral reflectance. In this study, 570 spectra between 380 and 2400 nm were obtained from soils with various soil moisture contents and salt concentrations in the laboratory; 3 soil types × 10 salt concentrations × 19 soil moisture levels were used. To examine the effectiveness of EPO, we compared the partial least squares regression (PLSR) results established from spectra with and without EPO correction. The EPO method effectively removed the effects of moisture, and the accuracy and robustness of the soil salt contents (SSCs) prediction model, which was built using the EPO-corrected spectra under various soil moisture conditions, were significantly improved relative to the spectra without EPO correction. This study contributes to the removal of soil moisture effects from soil salinity estimations when using vis–NIR reflectance spectroscopy and can assist others in quantifying soil salinity in the future. PMID:26468645

  10. [Development of an analyzing system for soil parameters based on NIR spectroscopy].

    PubMed

    Zheng, Li-Hua; Li, Min-Zan; Sun, Hong

    2009-10-01

    A rapid estimation system for soil parameters based on spectral analysis was developed by using object-oriented (OO) technology. A class of SOIL was designed. The instance of the SOIL class is the object of the soil samples with the particular type, specific physical properties and spectral characteristics. Through extracting the effective information from the modeling spectral data of soil object, a map model was established between the soil parameters and its spectral data, while it was possible to save the mapping model parameters in the database of the model. When forecasting the content of any soil parameter, the corresponding prediction model of this parameter can be selected with the same soil type and the similar soil physical properties of objects. And after the object of target soil samples was carried into the prediction model and processed by the system, the accurate forecasting content of the target soil samples could be obtained. The system includes modules such as file operations, spectra pretreatment, sample analysis, calibrating and validating, and samples content forecasting. The system was designed to run out of equipment. The parameters and spectral data files (*.xls) of the known soil samples can be input into the system. Due to various data pretreatment being selected according to the concrete conditions, the results of predicting content will appear in the terminal and the forecasting model can be stored in the model database. The system reads the predicting models and their parameters are saved in the model database from the module interface, and then the data of the tested samples are transferred into the selected model. Finally the content of soil parameters can be predicted by the developed system. The system was programmed with Visual C++6.0 and Matlab 7.0. And the Access XP was used to create and manage the model database. PMID:20038025

  11. Effective Soil Hydraulic Parameters Across Scales for Land-Atmosphere Interaction

    NASA Astrophysics Data System (ADS)

    Mohanty, B. P.; Ines, A. V.; Zhu, J.; Jana, R.; Das, N. N.; Sharma, S. K.

    2006-12-01

    Soil hydraulic properties (hydraulic conductivity, water retention) are by far the most important land surface parameters to govern the partitioning of soil moisture between infiltration and evaporation fluxes at a range of spatial scales. However, an obstacle to their practical application in the field, catchment, watershed, or regional scale is the difficulty of quantifying the "effective" soil hydraulic functions theta(h) and K(h), where theta is the soil water content, h is the pressure head and K is unsaturated hydraulic conductivity. Proper evaluation of the water balance near the land-atmosphere boundary depends strongly on appropriate characterization of soil hydraulic parameters under field conditions and at the appropriate process scale. In recent years we have adopted a multi-facet approach to this problem including: (1) a bottom-up approach, where larger-scale effective parameters are calculated by aggregating point-scale insitu hydraulic property measurements, (2) a top-down approach, where effective soil hydraulic parameters are estimated by inverse modeling using remotely sensed soil moisture measurements, and (3) an artificial neural network approach, where effective soil hydraulic parameters were estimated by exploiting the correlations with soil texture, topographic attributes, and vegetation characteristics at multiple spatial resolutions. Numerical and experimental results using these various effective soil hydraulic parameter estimation approaches including some comparisons between the approaches will be presented for the SGP and SMEX remote sensing experimental regions well as for the Rio Grande river basin.

  12. Parameters affecting extraction of selected fungicides from vineyard soils.

    PubMed

    Rial-Otero, Raquel; González-Rodríguez, Rosa María; Cancho-Grande, Beatriz; Simal-Gándara, Jesús

    2004-12-01

    This paper describes a sensitive method for the simultaneous quantification of eight commonly used grapevine fungicides in vineyard soils: cyprodinil, fludioxonil, metalaxyl, penconazole, pyrimethanil, procymidone, tebuconazole, and vinclozolin. The fungicides are extracted from the soil sample by sonication with water followed by shaking with ethyl acetate and are quantified by gas chromatography with mass spectrometry. Average extraction efficiencies in a sample of seven spiked, previously fungicide-free soils were > or =79% for all of the analytes, method precisions were > or =17%, and quantification limits were < or =50 microg/kg. However, because recoveries varied considerably from soil to soil, there is a need to control for soil matrix differences (mainly soil pH and exchangeable calcium content); as a consequence, soil fungicide contents must be quantified by the standard additions method. When the method was applied in this way to soil samples from vineyards belonging to the specified wine-growing region of Rias Baixas (Galicia, northwestern Spain) taken at the beginning of October (1 month after the crop's final treatment), levels of fludioxonil as high as 991 microg/kg were found, but at the start of the season (9 months after the previous crop's final treatment) only fludioxonil was detected at levels higher than its limit of quantification (45 and 52 microg/kg). PMID:15563199

  13. Towards an integrated petrophysical tool for multiphase flow properties of core samples

    SciTech Connect

    Lenormand, R.

    1997-08-01

    This paper describes the first use of an Integrated Petrophysical Tool (IPT) on reservoir rock samples. The IPT simultaneously measures the following petrophysical properties: (1) Complete capillary pressure cycle: primary drainage, spontaneous and forced imbibitions, secondary drainage (the cycle leads to the wettability of the core by using the USBM index); End-points and parts of the relative permeability curves; Formation factor and resistivity index. The IPT is based on the steady-state injection of one fluid through the sample placed in a Hassler cell. The experiment leading to the whole Pc cycle on two reservoir sandstones consists of about 30 steps at various oil or water flow rates. It takes about four weeks and is operated at room conditions. Relative permeabilities are in line with standard steady-state measurements. Capillary pressures are in accordance with standard centrifuge measurements. There is no comparison for the resistivity index, but the results are in agreement with literature data. However, the accurate determination of saturation remains the main difficulty and some improvements are proposed. In conclusion, the Integrated Petrophysical Tool is as accurate as standard methods and has the advantage of providing the various parameters on the same sample and during a single experiment. The FIT is easy to use and can be automated. In addition, it can be operated in reservoir conditions.

  14. Characterizing petrophysical properties of carbonate rocks using nuclear magnetic resonance and spectral induced polarization

    NASA Astrophysics Data System (ADS)

    Zhang, Fan; Zhang, Chi; Rankey, Eugene

    2016-04-01

    Unlike sandstones, with well-characterized correlations between porosity and permeability, carbonate rocks are well known for their highly complex petrophysical behaviors due to their intrinsically heterogeneous pore shape, pore size, and pore distributions and connectivity. The characterization of petrophysical properties of carbonate rocks, including rock properties and rock-fluid interactions, remains big challenges. This laboratory study focuses on integrating two geophysical methods: nuclear magnetic resonance (NMR) and spectral induced polarization (SIP) to determine porosity, pore size distribution, and permeability of carbonate rocks. NMR measures the relaxation of hydrogen nuclei at pore scale. Samples with different pore structures saturated by fluids have molecular relaxation responses to the external magnetic field which could generate various NMR signals. Permeability estimation from NMR in siliciclastic rocks is routine, however, is problematic in carbonates. SIP determines complex resistivity of a sample across a wide range of frequency and is sensitive to variations in the properties of solid-fluid and fluid-fluid interfaces in porous media. Previous studies investigated the relationships between permeability and parameters derived from SIP data, but are restricted to narrow lithology range. Our study used carbonate core samples from three depositional environments: tidal zone, shallow marine, and platform/reef margin of an atoll. Samples were fully saturated by water for T2 relaxation measurements and complex conductivity measurements at low frequencies. We compare the pore volume to surface area ratio measured from NMR and SIP and assess the applicability of established petrophysical models to estimate permeability from NMR and SIP data. We hope to build a relationship between NMR signals, SIP responses and petrophysical properties in carbonate rocks. The results could also provide new data and help further understand the unique and complex pore

  15. Quick and low cost measurement of soil parameters using a Kinect 3D scanner

    NASA Astrophysics Data System (ADS)

    Hut, R.; Van De Giesen, N.; Hagenaars, R.

    2013-12-01

    Retrieval of basic soil parameters such as bulk density and soil moisture from soil samples is a costly and time-consuming activity. Although indirect methods (heat or electromagnetic probes, radar backscatter, etc) are abundant, field truth measurement of soil parameters will remain important, if only to calibrate these other methods. We present a quick, field mountable setup to make 3D scans of surfaces up to 30 x 30 cm using a Kinect 3D scanner. By making scans before and after samples are taken, parameters such as bulk density and moisture content can easily be calculated.

  16. 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...

  17. DISTRIBUTION OF PARAMETERS DETERMINING BIOAVAILABILITY OF METALS IN EUROPEAN SOILS

    EPA Science Inventory

    As part of a program to develop a predictive model of bioavailability and toxicity of copper in soils to terrestrial organisms, 19 soils from 9 countries of the EU were collected and analyzed for use in bioavailability tests. However, it is desired that the model be of use on a ...

  18. Roughness parameter optimization using Land Parameter Retrieval Model and Soil Moisture Deficit: Implementation using SMOS brightness temperatures

    NASA Astrophysics Data System (ADS)

    Srivastava, Prashant K.; O'Neill, Peggy; Han, Dawei; Rico-Ramirez, Miguel A.; Petropoulos, George P.; Islam, Tanvir; Gupta, Manika

    2015-04-01

    Roughness parameterization is necessary for nearly all soil moisture retrieval algorithms such as single or dual channel algorithms, L-band Microwave Emission of Biosphere (LMEB), Land Parameter Retrieval Model (LPRM), etc. At present, roughness parameters can be obtained either by field experiments, although obtaining field measurements all over the globe is nearly impossible, or by using a land cover-based look up table, which is not always accurate everywhere for individual fields. From a catalogue of models available in the technical literature domain, the LPRM model was used here because of its robust nature and applicability to a wide range of frequencies. LPRM needs several parameters for soil moisture retrieval -- in particular, roughness parameters (h and Q) are important for calculating reflectivity. In this study, the h and Q parameters are optimized using the soil moisture deficit (SMD) estimated from the probability distributed model (PDM) and Soil Moisture and Ocean Salinity (SMOS) brightness temperatures following the Levenberg-Marquardt (LM) algorithm over the Brue catchment, Southwest of England, U.K.. The catchment is predominantly a pasture land with moderate topography. The PDM-based SMD is used as it is calibrated and validated using locally available ground-based information, suitable for large scale areas such as catchments. The optimal h and Q parameters are determined by maximizing the correlation between SMD and LPRM retrieved soil moisture. After optimization the values of h and Q have been found to be 0.32 and 0.15, respectively. For testing the usefulness of the estimated roughness parameters, a separate set of SMOS datasets are taken into account for soil moisture retrieval using the LPRM model and optimized roughness parameters. The overall analysis indicates a satisfactory result when compared against the SMD information. This work provides quantitative values of roughness parameters suitable for large scale applications. The

  19. Petrophysical core characterization at supercritical geothermal conditions

    NASA Astrophysics Data System (ADS)

    Kummerow, Juliane; Raab, Siegfried

    2015-04-01

    There is a growing scientific interest in the exploitation of supercritical geothermal reservoirs to increase the efficiency of geothermal power plants. The utilisation of geothermal energy requires in any case the detailed knowledge of the reservoir. In reservoir engineering, the characterisation of the geothermal system by electrical resistivity tomography (ERT) is a common geophysical exploration and monitoring strategy. For a realistic interpretation of the field measurements it is necessary to know both, the physical properties of the rock and those of the interacting fluid at defined temperature and pressure conditions. While there have been made great effort in determine the physical and chemical properties of water above its critical point (Tcritical = 374.21° C and pcritical = 221.2 bar), the influence of fluid-rock interactions on petrophysical properties in supercritical aqueous systems is nearly unknown. At supercritical conditions the viscosity of the fluid is low, which enhances the mass transfer and diffusion-controlled chemical reactions. This may have considerable effects on the porosity and hydraulic properties of a rock. To investigate high-enthalpy fluid-rock systems, in the framework of the EU-funded project IMAGE we have built a new percolation set-up, which allows for the measurement of electrical resistivity and permeability of rock samples at controlled supercritical conditions of aqueous fluids (pore pressure = 400 bar and a temperature = 400° C). First results will be presented.

  20. Determining photon energy absorption parameters for different soil samples

    PubMed Central

    Kucuk, Nil; Tumsavas, Zeynal; Cakir, Merve

    2013-01-01

    The mass attenuation coefficients (μs) for five different soil samples were measured at 661.6, 1173.2 and 1332.5 keV photon energies. The soil samples were separately irradiated with 137Cs and 60Co (370 kBq) radioactive point gamma sources. The measurements were made by performing transmission experiments with a 2″ × 2″ NaI(Tl) scintillation detector, which had an energy resolution of 7% at 0.662 MeV for the gamma-rays from the decay of 137Cs. The effective atomic numbers (Zeff) and the effective electron densities (Neff) were determined experimentally and theoretically using the obtained μs values for the soil samples. Furthermore, the Zeff and Neff values of the soil samples were computed for the total photon interaction cross-sections using theoretical data over a wide energy region ranging from 1 keV to 15 MeV. The experimental values of the soils were found to be in good agreement with the theoretical values. Sandy loam and sandy clay loam soils demonstrated poor photon energy absorption characteristics. However, clay loam and clay soils had good photon energy absorption characteristics. PMID:23179375

  1. Determining photon energy absorption parameters for different soil samples.

    PubMed

    Kucuk, Nil; Tumsavas, Zeynal; Cakir, Merve

    2013-05-01

    The mass attenuation coefficients (μs) for five different soil samples were measured at 661.6, 1173.2 and 1332.5 keV photon energies. The soil samples were separately irradiated with (137)Cs and (60)Co (370 kBq) radioactive point gamma sources. The measurements were made by performing transmission experiments with a 2″ × 2″ NaI(Tl) scintillation detector, which had an energy resolution of 7% at 0.662 MeV for the gamma-rays from the decay of (137)Cs. The effective atomic numbers (Zeff) and the effective electron densities (Neff) were determined experimentally and theoretically using the obtained μs values for the soil samples. Furthermore, the Zeff and Neff values of the soil samples were computed for the total photon interaction cross-sections using theoretical data over a wide energy region ranging from 1 keV to 15 MeV. The experimental values of the soils were found to be in good agreement with the theoretical values. Sandy loam and sandy clay loam soils demonstrated poor photon energy absorption characteristics. However, clay loam and clay soils had good photon energy absorption characteristics. PMID:23179375

  2. Research progress of on-the-go soil parameter sensors based on NIRS

    NASA Astrophysics Data System (ADS)

    An, Xiaofei; Meng, Zhijun; Wu, Guangwei; Guo, Jianhua

    2014-11-01

    Both the ever-increasing prices of fertilizer and growing ecological concern over chemical run-off into sources of drinking water have brought the issues of precision agriculture and site-specific management to the forefront of present technological development within agriculture and ecology. Soil is an important and basic element in agriculture production. Acquisition of soil information plays an important role in precision agriculture. The soil parameters include soil total nitrogen, phosporus, potassium, soil organic matter, soil moisture, electrical conductivity and pH value and so on. Field rapid acquisition to all the kinds of soil physical and chemical parameters is one of the most important research directions. And soil parameter real-time monitoring is also the trend of future development in precision agriculture. While developments in precision agriculture and site-specific management procedures have made significant in-roads on these issues and many researchers have developed effective means to determine soil properties, routinely obtaining robust on-the-go measurements of soil properties which are reliable enough to drive effective fertilizer application remains a challenge. NIRS technology provides a new method to obtain soil parameter with low cost and rapid advantage. In this paper, research progresses of soil on-the-go spectral sensors at domestic and abroad was combed and analyzed. There is a need for the sensing system to perform at least six key indexes for any on-the-go soil spectral sensor to be successful. The six indexes are detection limit, specificity, robustness, accuracy, cost and easy-to-use. Both the research status and problems were discussed. Finally, combining the national conditions of china, development tendency of on-the-go soil spectral sensors was proposed. In the future, on-the-go soil spectral sensors with reliable enough, sensitive enough and continuous detection would become popular in precision agriculture.

  3. Evaluating petrophysical relationships in fractured rock using geophysical measurements

    NASA Astrophysics Data System (ADS)

    Robinson, J.; Slater, L. D.; Keating, K.; Parker, B. L.; Rose, C.; Meyer, J. R.; Johnson, C. D.; Robinson, T.; Pehme, P.; Chapman, S.; Day-Lewis, F. D.

    2015-12-01

    Quantification of the pore geometric properties controlling mass transfer rates in fractured rock aquifers is a challenging characterization problem, especially given the scales of heterogeneity. The efficiency of in-situ remediation efforts that target hydraulically connected and dead-end fracture zones is limited, in part, due to the diffusion of aqueous phase contaminants into and out of the less-mobile pore spaces in the matrix surrounding fractures. Two geophysical technologies, complex resistivity (CR) and nuclear magnetic resonance (NMR) are sensitive to pore geometry and may provide key information on transport parameters where diffusion can be a limiting factor in and around boreholes. We present laboratory CR and NMR data from cores collected from field sites with variable lithologies and examine the sensitivity of these measurements to less-mobile versus mobile porosity. Supporting data include surface area measurements using the Brunauer-Emmett-Teller (BET) method, pore size distributions from mercury porosimetry, gravimetric measurements of matrix total porosity and gas permeability. We examine the predictive capability of CR and NMR to determine these pore scale properties as a function of geological setting. The petrophysical relationships illustrate the potential for use of new borehole logging tools to determine the spatial variability of physical properties controlling mass transfer close to fractures. The correlations of measurements to rock-type specific relations indicate that minimal core measurements might be needed to calibrate the results to a specific site.

  4. Elimination of the soil moisture effect on the spectra for reflectance prediction of soil salinity using external parameter orthogonalization method

    NASA Astrophysics Data System (ADS)

    Peng, Xiang; Xu, Chi; Zeng, Wenzhi; Wu, JingWei; Huang, JieSheng

    2016-01-01

    Soil salinization is a common desertification process, especially in arid lands. Hyperspectral remote sensing of salinized soil is favored for its advantages of being efficient and inexpensive. However, soil moisture often jointly has a great influence on the soil reflectance spectra under field conditions. It is a challenge to establish a model to eliminate the effect of soil moisture and quantitatively estimate the salinity contents of slightly and moderately salt-affected soil. A controlled laboratory experiment was conducted by way of continuously monitoring changes of soil moisture and salt content, which was mainly focused on the slightly and moderately salt-affected soil. We investigated the external parameter orthogonalization (EPO) method to remove the effect of soil moisture (4 to 36% in weight base) by preprocessing soil spectral reflectance and establishing the partial least squares regression after EPO preprocessing model (EPO-PLS) to predict soil salt content. Through comparing PLS with EPO-PLS model, R2 and ratio of prediction to deviation rose from 0.604 and 1.063, respectively, to 0.874 and 2.865 for validation data. Root mean square error and bias were, respectively, reduced from 1.163 and 0.141 g/100 g to 0.718 and 0.044 g/100 g. The performance of the model after EPO algorithm preprocessing was improved significantly.

  5. Evolution of Fractal Parameters through Development Stage of Soil Crust

    NASA Astrophysics Data System (ADS)

    Ospina, Abelardo; Florentino, Adriana; Tarquis, Ana Maria

    2016-04-01

    Soil surface characteristics are subjected to changes driven by several interactions between water, air, biotic and abiotic components. One of the examples of such interactions is provided through biological soil crusts (BSC) in arid and semi-arid environments. BSC are communities composed of cyanobacteria, fungi, mosses, lichens, algae and liverworts covering the soil surface and play an important role in ecosystem functioning. The characteristics and formation of these BSC influence the soil hydrological balance, control the mass of eroded sediment, increase stability of soil surface, and influence plant productivity through the modification of nitrogen and carbon cycle. The site of this work is located at Quibor and Ojo de Agua (Lara state, Venezuela). The Quibor Depression in Venezuela is a major agricultural area being at semi-arid conditions and limited drainage favor the natural process of salinization. Additionally, the extension and intensification of agriculture has led to over-exploitation of groundwater in the past 30 years (Méndoza et al., 2013). The soil microbial crust develops initially on physical crusts which are mainly generated since wetting and drying, being a recurrent feature in the Quíbor arid zone. The microbiotic crust is organic, composed of macro organisms (bryophytes and lichens) and microorganisms (cyanobacteria, fungi algae, etc.); growing on the ground, forming a thickness no greater than 3 mm. For further details see Toledo and Florentino (2009). This study focus on characterize the development stage of the BSC based on image analysis. To this end, grayscale images of different types of biological soil crust at different stages where taken, each image corresponding to an area of 12.96 cm2 with a resolution of 1024x1024 pixels (Ospina et al., 2015). For each image lacunarity and fractal dimension through the differential box counting method were calculated. These were made with the software ImageJ/Fraclac (Karperien, 2013

  6. Toxicity assessment of two soils from Jales mine (Portugal) using plants: growth and biochemical parameters.

    PubMed

    Loureiro, Susana; Santos, Conceição; Pinto, Glória; Costa, Armando; Monteiro, Marta; Nogueira, António J A; Soares, Amadeu M V M

    2006-02-01

    Contaminants in soils can enter food chains through primary producers. Bioavailable contaminants can induce growth, and reproductive or biochemical changes in plants. To evaluate the bioavailability of heavy metals in two soils from Jales mine surroundings, bioassays with the plants Brassica rapa (RCBr) and Avena sativa were performed. Biochemical parameters (protein and malondialdehyde [MDA] content, and catalase and peroxidase activities) were also measured. The soils had different heavy metal contents: JNC soil contained low heavy metal concentrations, whereas JC soil had high heavy metal contents. Results stressed the difference between species sensitivity, with A. sativa showing no toxicity effects when exposed to both soils. On the other hand, B. rapa presented a decrease in growth parameters when exposed to JNC soil and no changes when exposed to JC soil. A Life Cycle Bioassay confirmed this trend for B. rapa exposed to JNC soil, but also evidenced that JC soil was affecting B. rapa in terms of flower and seed pod production. Biochemical assays showed that plants affected by heavy metals also displayed oxidative stress, with an increase in MDA production, reduction of protein content, and reduction of catalase and peroxidase activities. All bioassays revealed that JNC soil, although with a lower heavy metal content, had a higher bioavailable fraction when compared to JC soil, which consequently increased its toxicity to plants. PMID:16307215

  7. Joint inversion of geophysical data using petrophysical clustering and facies deformation wth the level set technique

    NASA Astrophysics Data System (ADS)

    Revil, A.

    2015-12-01

    Geological expertise and petrophysical relationships can be brought together to provide prior information while inverting multiple geophysical datasets. The merging of such information can result in more realistic solution in the distribution of the model parameters, reducing ipse facto the non-uniqueness of the inverse problem. We consider two level of heterogeneities: facies, described by facies boundaries and heteroegenities inside each facies determined by a correlogram. In this presentation, we pose the geophysical inverse problem in terms of Gaussian random fields with mean functions controlled by petrophysical relationships and covariance functions controlled by a prior geological cross-section, including the definition of spatial boundaries for the geological facies. The petrophysical relationship problem is formulated as a regression problem upon each facies. The inversion of the geophysical data is performed in a Bayesian framework. We demonstrate the usefulness of this strategy using a first synthetic case for which we perform a joint inversion of gravity and galvanometric resistivity data with the stations located at the ground surface. The joint inversion is used to recover the density and resistivity distributions of the subsurface. In a second step, we consider the possibility that the facies boundaries are deformable and their shapes are inverted as well. We use the level set approach to perform such deformation preserving prior topological properties of the facies throughout the inversion. With the help of prior facies petrophysical relationships and topological characteristic of each facies, we make posterior inference about multiple geophysical tomograms based on their corresponding geophysical data misfits. The method is applied to a second synthetic case showing that we can recover the heterogeneities inside the facies, the mean values for the petrophysical properties, and, to some extent, the facies boundaries using the 2D joint inversion of

  8. Soil Parameters Drive the Structure, Diversity and Metabolic Potentials of the Bacterial Communities Across Temperate Beech Forest Soil Sequences.

    PubMed

    Jeanbille, M; Buée, M; Bach, C; Cébron, A; Frey-Klett, P; Turpault, M P; Uroz, S

    2016-02-01

    Soil and climatic conditions as well as land cover and land management have been shown to strongly impact the structure and diversity of the soil bacterial communities. Here, we addressed under a same land cover the potential effect of the edaphic parameters on the soil bacterial communities, excluding potential confounding factors as climate. To do this, we characterized two natural soil sequences occurring in the Montiers experimental site. Spatially distant soil samples were collected below Fagus sylvatica tree stands to assess the effect of soil sequences on the edaphic parameters, as well as the structure and diversity of the bacterial communities. Soil analyses revealed that the two soil sequences were characterized by higher pH and calcium and magnesium contents in the lower plots. Metabolic assays based on Biolog Ecoplates highlighted higher intensity and richness in usable carbon substrates in the lower plots than in the middle and upper plots, although no significant differences occurred in the abundance of bacterial and fungal communities along the soil sequences as assessed using quantitative PCR. Pyrosequencing analysis of 16S ribosomal RNA (rRNA) gene amplicons revealed that Proteobacteria, Acidobacteria and Bacteroidetes were the most abundantly represented phyla. Acidobacteria, Proteobacteria and Chlamydiae were significantly enriched in the most acidic and nutrient-poor soils compared to the Bacteroidetes, which were significantly enriched in the soils presenting the higher pH and nutrient contents. Interestingly, aluminium, nitrogen, calcium, nutrient availability and pH appeared to be the best predictors of the bacterial community structures along the soil sequences. PMID:26370112

  9. Petrophysical characterization of the Marlin Discovery, Deepwater Gulf of Mexico

    SciTech Connect

    Clemenceau, G.R.; Lockett, C.F. )

    1996-01-01

    This presentation discusses the petrophysical characterization of the Marlin discovery, a high quality gas and oil reservoir in the Deepwater Northern Gulf of Mexico. Amoco drilled the Marlin discovery well in May 1993 on Viosca Knoll Block 915. Approximately 100 MMBOE is structurally trapped here within Miocene deep-sea tan sands at 11,000 feet subsea. The petrophysical characterization of Marlin is based upon conventional core tests and data from three wells. The Marlin reservoir rock types are characterized based upon differences between their petrophysical properties. The properties, which include porosity, permeability, pore throat radius, and grain size, are derived from routine and special core analysis of a 40 foot conventional core recovered from the discovery well. Relative permeability, and capillary pressure tests, conducted at reservoir stress, further describe the rock types. The petrophysical properties average as follows; porosity 28%, permeability 1200 mD, porethroat radius 24 microns, and mean grain size 180 microns. By integrating this petrophysical model with a geologic model, that utilizes conventional core, well log, and 3D seismic interpretation, a 3-dimensional flow unit model was created for input to a reservoir simulation.

  10. Effects of hazelnut husk compost application on soil quality parameters in hazelnut orchards in Turkey

    NASA Astrophysics Data System (ADS)

    Kizilkaya, Ridvan

    2016-04-01

    The long-term application of excessive chemical fertilizers has resulted in the degeneration of soil quality parameters such as soil microbial biomass, respiration, and nutrient content, which in turn affects crop health, productivity, and soil sustainable productivity. The objective of this study was to develop a rapid and efficient solution for rehabilitating degraded two hazelnut orchards having different textures by precisely quantifying soil quality parameters through the application of different doses (0, 1.25, 2.5, 5.0, 7.5 and 10 ton da-1) of hazelnut husk compost (HH) during hazelnut growth. After nine months of HHC application, soil quality parameters such as microbial biomass carbon (Cmic), basal respiration (BSR), total organic carbon (Corg), total N, C/N ratio, aggregate stability and some soil chemical properties (pH, EC and NO3-N content) were carried out on collected soil samples. The results showed that soil quality parameters were significantly affected by soil texture and HHC application doses. In general, Cmic, BSR, C/N ratio and the contents of Corg and N increased (P<0,001) and Cmic/Corg values decreased (P<0,001) with increasing HHC application in comparison with the control. In addition, HHC markedly increased the contents of NO3-N, the aggregate stability of soil, and the hydrolic conductivity in the soil were notably heightened. According to the results of field experiments conducted different location and condition, when the focusing on the organic substance management and sustainability of the quality parameters in soil, it was clear from the evidence obtained the research that the ideal HHC application was 5 ton per decare to increase the organic matter content by 2%. (This research was supported by The Scientific and Technological Research Council of Turkey, Project number: 111O698).

  11. Estimability analysis for optimization of hysteretic soil hydraulic parameters using data of a field irrigation experiment

    NASA Astrophysics Data System (ADS)

    Ngo, Viet V.; Gerke, Horst H.; Badorreck, Annika

    2014-05-01

    The estimability analysis has been proposed to improve the quality of parameter optimization. For field data, wetting and drying processes may complicate optimization of soil hydraulic parameters. The objectives of this study were to apply estimability analysis for improving optimization of soil hydraulic parameters and compare models with and without considering hysteresis. Soil water pressure head data of a field irrigation experiment were used. The one-dimensional vertical water movement in variably-saturated soil was described with the Richards equation using the HYDRUS-1D code. Estimability of the unimodal van Genuchten - Mualem hydraulic model parameters as well as of the hysteretic parameter model of Parker and Lenhard was classified according to a sensitivity coefficient matrix. The matrix was obtained by sequentially calculating effects of initial parameter variations on changes in the simulated pressure head values. Optimization was carried out by means of the Levenberg-Marquardt method as implemented in the HYDRUS-1D code. The parameters α, Ks, θs, and n in the nonhysteretic model were found sensitive and parameter θs and n strongly correlated with parameter n in the nonhysteretic model. When assuming hysteresis, the estimability was highest for αw and decreased with soil depth for Ks and αd, and increased for θs and n. The hysteretic model could approximate the pressure heads in the soil by considering parameters from wetting and drying periods separately as initial estimates. The inverse optimization could be carried out more efficiently with most estimable parameters. Despite the weaknesses of the local optimization algorithm and the inflexibility of the unimodal van Genuchten model, the results suggested that estimability analysis could be considered as a guidance to better define the optimization scenarios and then improved the determination of soil hydraulic parameters.

  12. Predicted Infiltration for Sodic/Saline Soils from Reclaimed Coastal Areas: Sensitivity to Model Parameters

    PubMed Central

    She, Dongli; Yu, Shuang'en; Shao, Guangcheng

    2014-01-01

    This study was conducted to assess the influences of soil surface conditions and initial soil water content on water movement in unsaturated sodic soils of reclaimed coastal areas. Data was collected from column experiments in which two soils from a Chinese coastal area reclaimed in 2007 (Soil A, saline) and 1960 (Soil B, nonsaline) were used, with bulk densities of 1.4 or 1.5 g/cm3. A 1D-infiltration model was created using a finite difference method and its sensitivity to hydraulic related parameters was tested. The model well simulated the measured data. The results revealed that soil compaction notably affected the water retention of both soils. Model simulations showed that increasing the ponded water depth had little effect on the infiltration process, since the increases in cumulative infiltration and wetting front advancement rate were small. However, the wetting front advancement rate increased and the cumulative infiltration decreased to a greater extent when θ0 was increased. Soil physical quality was described better by the S parameter than by the saturated hydraulic conductivity since the latter was also affected by the physical chemical effects on clay swelling occurring in the presence of different levels of electrolytes in the soil solutions of the two soils. PMID:25197699

  13. GPR based soil electromagnetic parameters determination for subsurface imaging

    NASA Astrophysics Data System (ADS)

    Solimene, R.; Prisco, G.; Soldovieri, F.

    2008-11-01

    The problem of estimating the dielectric permittivity and the electric conductivity of the soil starting from GPR measurements is addressed. A new estimation procedure is proposed and checked against synthetic data generated by a FDTD forward solver. A two-dimensional geometry and a two-layered background medium are considered.

  14. EVALUATING SOIL EROSION PARAMETER ESTIMATES FROM DIFFERENT DATA SOURCES

    EPA Science Inventory

    Topographic factors and soil loss estimates that were derived from thee data sources (STATSGO, 30-m DEM, and 3-arc second DEM) were compared. Slope magnitudes derived from the three data sources were consistently different. Slopes from the DEMs tended to provide a flattened sur...

  15. Applying petrophysical models to radar travel time and electrical resistivity tomograms: Resolution-dependent limitations

    USGS Publications Warehouse

    Day-Lewis, F. D.; Singha, K.; Binley, A.M.

    2005-01-01

    Geophysical imaging has traditionally provided qualitative information about geologic structure; however, there is increasing interest in using petrophysical models to convert tomograms to quantitative estimates of hydrogeologic, mechanical, or geochemical parameters of interest (e.g., permeability, porosity, water content, and salinity). Unfortunately, petrophysical estimation based on tomograms is complicated by limited and variable image resolution, which depends on (1) measurement physics (e.g., electrical conduction or electromagnetic wave propagation), (2) parameterization and regularization, (3) measurement error, and (4) spatial variability. We present a framework to predict how core-scale relations between geophysical properties and hydrologic parameters are altered by the inversion, which produces smoothly varying pixel-scale estimates. We refer to this loss of information as "correlation loss." Our approach upscales the core-scale relation to the pixel scale using the model resolution matrix from the inversion, random field averaging, and spatial statistics of the geophysical property. Synthetic examples evaluate the utility of radar travel time tomography (RTT) and electrical-resistivity tomography (ERT) for estimating water content. This work provides (1) a framework to assess tomograms for geologic parameter estimation and (2) insights into the different patterns of correlation loss for ERT and RTT. Whereas ERT generally performs better near boreholes, RTT performs better in the interwell region. Application of petrophysical models to the tomograms in our examples would yield misleading estimates of water content. Although the examples presented illustrate the problem of correlation loss in the context of near-surface geophysical imaging, our results have clear implications for quantitative analysis of tomograms for diverse geoscience applications. Copyright 2005 by the American Geophysical Union.

  16. Variations in petrophysical properties of shales along a stratigraphic section in the Whitby mudstone (UK)

    NASA Astrophysics Data System (ADS)

    Barnhoorn, Auke; Houben, Maartje; Lie-A-Fat, Joella; Ravestein, Thomas; Drury, Martyn

    2015-04-01

    In unconventional tough gas reservoirs (e.g. tight sandstones or shales) the presence of fractures, either naturally formed or hydraulically induced, is almost always a prerequisite for hydrocarbon productivity to be economically viable. One of the formations classified so far as a potential interesting formation for shale gas exploration in the Netherlands is the Lower Jurassic Posidonia Shale Formation (PSF). However data of the Posidonia Shale Formation is scarce so far and samples are hard to come by, especially on the variability and heterogeneity of the petrophysical parameters of this shale little is known. Therefore research and sample collection is conducted on a time and depositional analogue of the PSF: the Whitby Mudstone Formation (WMF) in the United Kingdom. A large number of samples along a ~7m stratigraphic section of the Whitby Mudstone Formation have been collected and analysed. Standard petrophysical properties such as porosity and matrix densities are quantified for a number of samples throughout the section, as well as mineral composition analysis based on XRD/XRF and SEM analyses. Seismic velocity measurements are also conducted at multiple heights in the section and in multiple directions to elaborate on anisotropy of the material. Attenuation anisotropy is incorporated as well as Thomsen's parameters combined with elastic parameters, e.g. Young's modulus and Poisson's ratio, to quantify the elastic anisotropy. Furthermore rock mechanical experiments are conducted to determine the elastic constants, rock strength, fracture characteristics, brittleness index, fraccability and rock mechanical anisotropy across the stratigraphic section of the Whitby mudstone formation. Results show that the WMF is highly anisotropic and it exhibits an anisotropy on the large limit of anisotropy reported for US gas shales. The high anisotropy of the Whitby shales has an even larger control on the formation of the fracture network. Furthermore, most petrophysical

  17. Deforestation effects on soil quality and water retention curve parameters in eastern Ardabil, Iran

    NASA Astrophysics Data System (ADS)

    Asghari, Sh.; Ahmadnejad, S.; Keivan Behjou, F.

    2016-03-01

    The land use change from natural to managed ecosystems causes serious soil degradation. The main objective of this research was to assess deforestation effects on soil physical quality attributes and soil water retention curve (SWRC) parameters in the Fandoghlou region of Ardabil province, Iran. Totally 36 surface and subsurface soil samples were taken and soil water contents measured at 13 suctions. Alfa (α) and n parameters in van Genuchten (1980) model were estimated by fitting SWRC data by using RETC software. The slope of SWRC at inflection point (SP) was calculated by Dexter (2004) equation. The results indicated that with changing land use from forest (F) to range land (R) and cultivated land (C), and also with increasing soil depth from 0-25 to 75-100 cm in each land use, organic carbon, micropores, saturated and available water contents decreased and macropores and bulk density increased significantly ( P < 0.05). The position of SWRC shape in F was higher than R and C lands at all soil depths. Changing F to R and C lands and also increasing soil depth in each land use significantly ( P < 0.05) increased α and decreased n and SP. The average values of SP were obtained 0.093, 0.051 and 0.031 for F, R and C, respectively. As a result, deforestation reduced soil physical quality by affecting SWRC parameters.

  18. Online vegetation parameter estimation using passive microwave observations for soil moisture estimation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vegetation affects the ability to estimate soil moisture from passive microwave observations by attenuating the surface soil moisture signal. To use radiobrightness observations in land data assimilation a vegetation opacity parameter is required as input to a radiative transfer model, which maps su...

  19. Deriving parameters of a fundamental detachment model for cohesive soils from flume and jet erosion tests

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The erosion rate of cohesive soils is commonly quantified using the excess shear stress equation, dependent on two major soil parameters: the critical shear stress and the erodibility coefficient. A submerged jet test (JET – Jet Erosion Test) is one method that has been developed for measuring thes...

  20. Assessment of SMOS Soil Moisture Retrieval Parameters Using Tau-Omega Algorithms for Soil Moisture Deficit Estimation

    NASA Technical Reports Server (NTRS)

    Srivastava, Prashant K.; Han, Dawei; Rico-Ramirez, Miguel A.; O'Neill, Peggy; Islam, Tanvir; Gupta, Manika

    2014-01-01

    Soil Moisture and Ocean Salinity (SMOS) is the latest mission which provides flow of coarse resolution soil moisture data for land applications. However, the efficient retrieval of soil moisture for hydrological applications depends on optimally choosing the soil and vegetation parameters. The first stage of this work involves the evaluation of SMOS Level 2 products and then several approaches for soil moisture retrieval from SMOS brightness temperature are performed to estimate Soil Moisture Deficit (SMD). The most widely applied algorithm i.e. Single channel algorithm (SCA), based on tau-omega is used in this study for the soil moisture retrieval. In tau-omega, the soil moisture is retrieved using the Horizontal (H) polarisation following Hallikainen dielectric model, roughness parameters, Fresnel's equation and estimated Vegetation Optical Depth (tau). The roughness parameters are empirically calibrated using the numerical optimization techniques. Further to explore the improvement in retrieval models, modifications have been incorporated in the algorithms with respect to the sources of the parameters, which include effective temperatures derived from the European Center for Medium-Range Weather Forecasts (ECMWF) downscaled using the Weather Research and Forecasting (WRF)-NOAH Land Surface Model and Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) while the s is derived from MODIS Leaf Area Index (LAI). All the evaluations are performed against SMD, which is estimated using the Probability Distributed Model following a careful calibration and validation integrated with sensitivity and uncertainty analysis. The performance obtained after all those changes indicate that SCA-H using WRF-NOAH LSM downscaled ECMWF LST produces an improved performance for SMD estimation at a catchment scale.

  1. Likelihood parameter estimation for calibrating a soil moisture using radar backscatter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Assimilating soil moisture information contained in synthetic aperture radar imagery into land surface model predictions can be done using a calibration, or parameter estimation, approach. The presence of speckle, however, necessitates aggregating backscatter measurements over large land areas in or...

  2. In-situ determination of strength parameters of marine soils

    SciTech Connect

    McNeill, R. L.; Green, S. L.

    1980-01-01

    Principles are developed whereby both the sear strength, S, and the effective soil strength angle, phi', can be calculated from the readings of a combined shear/normal-stress gauge mounted on the face of a rough penetrator. The method calculates S and phi' even if interface friction is the mechanism of failure, unless that friction is local to the gauge face. In that case, the method yields only the interface friction angle, delta.

  3. Surface Roughness Parameter Uncertainties on Radar Based Soil Moisture Retrievals

    NASA Technical Reports Server (NTRS)

    Joseph, A. T.; vanderVelde, R.; O'Neill, P. E.; Lang, R.; Su, Z.; Gish, T.

    2012-01-01

    Surface roughness variations are often assumed to be negligible for the retrieval of sol moisture. Although previous investigations have suggested that this assumption is reasonable for natural vegetation covers (i.e. Moran et al. 2002), in-situ measurements over plowed agricultural fields (i.e. Callens et al. 2006) have shown that the soil surface roughness can change considerably due to weathering induced by rain.

  4. Responses of Water and Salt Parameters to Groundwater Levels for Soil Columns Planted with Tamarix chinensis

    PubMed Central

    Xia, Jiangbao; Zhao, Ximei; Chen, Yinping; Fang, Ying; Zhao, Ziguo

    2016-01-01

    Groundwater is the main water resource for plant growth and development in the saline soil of the Yellow River Delta in China. To investigate the variabilities and distributions of soil water and salt contents at various groundwater level (GL), soil columns with planting Tamarix chinensis Lour were established at six different GL. The results demonstrated the following: With increasing GL, the relative soil water content (RWC) declined significantly, whereas the salt content (SC) and absolute soil solution concentration (CS) decreased after the initial increase in the different soil profiles. A GL of 1.2 m was the turning point for variations in the soil water and salt contents, and it represented the highest GL that could maintain the soil surface moist within the soil columns. Both the SC and CS reached the maximum levels in these different soil profiles at a GL of 1.2 m. With the raise of soil depth, the RWC increased significantly, whereas the SC increased after an initial decrease. The mean SC values reached 0.96% in the top soil layer; however, the rates at which the CS and RWC decreased with the GL were significantly reduced. The RWC and SC presented the greatest variations at the medium (0.9–1.2 m) and shallow water levels (0.6 m) respectively, whereas the CS presented the greatest variation at the deep water level (1.5–1.8 m).The RWC, SC and CS in the soil columns were all closely related to the GL. However, the correlations among the parameters varied greatly within different soil profiles, and the most accurate predictions of the GL were derived from the RWC in the shallow soil layer or the SC in the top soil layer. A GL at 1.5–1.8 m was moderate for planting T. chinensis seedlings under saline groundwater conditions. PMID:26730602

  5. Geostatistical analysis of the soil and crop parameters in a field experiment on precision agriculture

    NASA Astrophysics Data System (ADS)

    Sidorova, V. A.; Zhukovskii, E. E.; Lekomtsev, P. V.; Yakushev, V. V.

    2012-08-01

    A thorough geostatistical analysis was performed of the spatial variability of the soil properties, the sowing parameters, and the wheat yield in a field experiment under precision agriculture conditions. It was found that most of the soil parameters are significantly correlated and can be successfully mapped using kriging procedures, which ensure the optimum development of agrochemical cartograms for agricultural fields. It was also shown that the sowing parameters had a significantly lower spatial correlation; their cartograms could be drawn, although with worse accuracy. The quality parameters of the wheat grain showed no spatial correlation.

  6. Soybean fungal soil-borne diseases: a parameter for measuring the effect of agricultural intensification on soil health.

    PubMed

    Pérez-Brandán, C; Huidobro, J; Grümberg, B; Scandiani, M M; Luque, A G; Meriles, J M; Vargas-Gil, S

    2014-02-01

    The aim of this study was to investigate the influence of agricultural intensification on soil microbial diversity, chemical and physical parameters, and the decrease of the incidence of sudden death syndrome (Fusarium crassistipitatum) and charcoal rot (Macrophomina phaseolina) in soybean. Soils under different management systems were evaluated during 2 crop cycles: soybean monoculture for 24 and 11 years, soybean-maize rotation for 15 and 4 years, 1 year of soybean, and native vegetation. The incidence of both soil-borne diseases was higher under monoculture than under rotation. Increased populations of potential biocontrol agents (Trichoderma spp., Gliocladium spp., fluorescent pseudomonads) were associated with rotation treatments, especially in 2010-2011. The comparison of agricultural vs. native vegetation soil and the average of agricultural cycles showed that microbial biomass carbon and glomalin-related soil protein were higher in the rotation system than in monoculture (50% and 77%, respectively). Furthermore, from the community-level functional diversity (Biolog Eco plates), McIntosh index showed lower functional diversity in monoculture than in rotation and native vegetation plots. Agricultural intensification reduced microbial biomass carbon, glomalin-related soil protein, organic matter, total nitrogen, aggregate stability, and yield, and increased bulk density. Soil quality degradation was associated with the establishment of soil-borne pathogens and increased soybean plant susceptibility to disease. PMID:24498984

  7. Geomechanical and Petrophysical Properties of Rift Basin Mudstones

    NASA Astrophysics Data System (ADS)

    Zakharova, N. V.; Goldberg, D.; Collins, D.; Malkewicz, N.

    2015-12-01

    Mudstone caprocks are important components of reservoir systems in a variety of geologic and geoingeneering applications, but their properties and behavior under in situ conditions remain only partially understood. This study presents a detailed analysis of geomechanical and petrophysical properties of 20 lacustrine mudstones from the Mesozoic Newark Rift Basin, the largest of exposed rift basins in eastern North America, considered as a potential CO2 sequestration site. The samples were selected to represent variable lithology, organic content, redox state, structure (massive and thinly bedded), degree of matrix anisotropy, and burial depths. An extensive characterization program was funded by the U.S. Department of Energy's National Energy Technology Laboratory (NETL), and included laboratory CT scans, XRD, SEM, MICP, porosity, permeability, and acoustic velocity measurements, as well as geomechanical testing of both matrix and fracture strength under a range of confining pressures. Core measurements were integrated with available logging data to allow for multiscale comparison and correlation. Most of the analyzed mudstones have the clay content of 50-70%, with abundant mica and detrital grains. The pore system is dominated by narrow micropores (mostly <5-100 microns wide), and nano-scale pore throats (0.005-0.05 microns). Full Mohr-Coulomb failure envelopes built for each mudstone type indicate a large variability in projected unconfined strength and the coefficient of internal friction. The dataset allows building empirical relations between compositional, structural and mechanical properties of these lacustrine mudstones, as well as physical parameters such as acoustic velocity (both laboratory and logging) and elastic moduli. These relations can be applied to other lacustrine mudstones in the East American rift basins, and provide important information for caprock stability modeling in these basins.

  8. Relation between various soil phosphorus extraction methods and sorption parameters in calcareous soils with different texture.

    PubMed

    Jalali, Mohsen; Jalali, Mahdi

    2016-10-01

    The aim of this study was to investigate the influence of soil texture on phosphorus (P) extractability and sorption from a wide range of calcareous soils across Hamedan, western Iran. Fifty seven soil samples were selected and partitioned into five types on the basis of soil texture (clay, sandy, sandy clay loam, sandy loam and mixed loam) and the P extracted with calcium chloride (PCaCl2), citrate (Pcitrate), HCl (PHCl), Olsen (POls), and Mehlich-3 (PM3) solutions. On the average, the P extracted was in the order PHCl>PM3>Pcitrate>POls>PCaCl2. The P extracted by Pcitrate, PHCl, POls, and PM3 methods were significantly higher in sandy, sandy clay loam and sandy loam textures than clay and mixed loam textures, while soil phosphorus buffer capacity (PBC) was significantly higher in clay and mixed loam soil textures. The correlation analysis revealed a significant positive relationship between silt content Freundlich sorption coefficient (KF), maximum P sorption (Qmax), linear distribution coefficient (Kd), and PBC. All extractions were highly correlated with each other and among soil components with silt content. The principal component analysis (PCA) performed on data identified five principal components describing 74.5% of total variation. The results point to soil texture as an important factor and that silt was the crucial soil property associated with P sorption and its extractability in these calcareous soils. DPSM3-2 (PM3PM3+Qmax×100) and DPScitrate (PcitratePcitrate+Qmax×100) proved to be good indicators of soil's potential P release in these calcareous soils. Among the DPS, 21% of soils reported DPSM3-2, values higher than the environmental threshold, indicating build-up of P and P release. Most of the studied sandy clay loam soils had exceeded the environmentally unacceptable P concentration. Various management practices should be taken into account to reduce P losses from these soils. Further inorganic and organic P fertilizer inputs should be reduced

  9. Changes in multifractal parameters from profiles of soil penetration resistance obtained with increasing soil dryness

    NASA Astrophysics Data System (ADS)

    Germán Wilson, Marcelo; Lado Liñares, Marcos; González, Antonio Paz

    2015-04-01

    Soil penetration resistance (PR) is linked to basic soil physical properties and correlated to root growth and plant production, so that it has been extensively used as a practical tool for assessing soil compaction and to evaluate the effects of soil management on soil physical quality. We analyzed multifractality of PR vertical profiles, measured from 0 to 80 cm depth at 1 cm intervals. Soil PR was recorded at 10 successive dates with decreasing soil water content in Entre Ríos Province, Argentina, and 10 replicate PR profiles were obtained in each date. The scaling property of each depth-dependent PR profile was typified by the singularity spectrum, αs versus f(α)s and the generalized dimension spectrum, estimated by the method of moments. Both, singularity and Rènyi spectra showed the vertical PR data sets exhibited a well-defined multifractal structure. The multifractality (scaling heterogeneity) in our data series decreased as the mean soil water content decreased. Overall, singularity spectra were asymmetrical and shifted to the right, which is compatible with a greater heterogeneity of the low values in the PR data sets studied. The entropy dimension, D1, increased with decreasing soil water content, and mean values ranged from 0.956 to 0.981; this means that the wetter the soil the more homogeneously is distributed the measure over a large range of scales. Multifractal analysis yielded information about changes with scale of the higher moments, which gives a deep insight into the inner structure of soil PR depth-dependent profiles.

  10. Intelligent approaches for the synthesis of petrophysical logs

    NASA Astrophysics Data System (ADS)

    Rezaee, M. Reza; Kadkhodaie-Ilkhchi, Ali; Alizadeh, Pooya Mohammad

    2008-03-01

    Log data are of prime importance in acquiring petrophysical data from hydrocarbon reservoirs. Reliable log analysis in a hydrocarbon reservoir requires a complete set of logs. For many reasons, such as incomplete logging in old wells, destruction of logs due to inappropriate data storage and measurement errors due to problems with logging apparatus or hole conditions, log suites are either incomplete or unreliable. In this study, fuzzy logic and artificial neural networks were used as intelligent tools to synthesize petrophysical logs including neutron, density, sonic and deep resistivity. The petrophysical data from two wells were used for constructing intelligent models in the Fahlian limestone reservoir, Southern Iran. A third well from the field was used to evaluate the reliability of the models. The results showed that fuzzy logic and artificial neural networks were successful in synthesizing wireline logs. The combination of the results obtained from fuzzy logic and neural networks in a simple averaging committee machine (CM) showed a significant improvement in the accuracy of the estimations. This committee machine performed better than fuzzy logic or the neural network model in the problem of estimating petrophysical properties from well logs.

  11. Moisture can be the dominant environmental parameter governing cadaver decomposition in soil.

    PubMed

    Carter, David O; Yellowlees, David; Tibbett, Mark

    2010-07-15

    Forensic taphonomy involves the use of decomposition to estimate postmortem interval (PMI) or locate clandestine graves. Yet, cadaver decomposition remains poorly understood, particularly following burial in soil. Presently, we do not know how most edaphic and environmental parameters, including soil moisture, influence the breakdown of cadavers following burial and alter the processes that are used to estimate PMI and locate clandestine graves. To address this, we buried juvenile rat (Rattus rattus) cadavers (approximately 18 g wet weight) in three contrasting soils from tropical savanna ecosystems located in Pallarenda (sand), Wambiana (medium clay), or Yabulu (loamy sand), Queensland, Australia. These soils were sieved (2mm), weighed (500 g dry weight), calibrated to a matric potential of -0.01 megapascals (MPa), -0.05 MPa, or -0.3 MPa (wettest to driest) and incubated at 22 degrees C. Measurements of cadaver decomposition included cadaver mass loss, carbon dioxide-carbon (CO(2)-C) evolution, microbial biomass carbon (MBC), protease activity, phosphodiesterase activity, ninhydrin-reactive nitrogen (NRN) and soil pH. Cadaver burial resulted in a significant increase in CO(2)-C evolution, MBC, enzyme activities, NRN and soil pH. Cadaver decomposition in loamy sand and sandy soil was greater at lower matric potentials (wetter soil). However, optimal matric potential for cadaver decomposition in medium clay was exceeded, which resulted in a slower rate of cadaver decomposition in the wettest soil. Slower cadaver decomposition was also observed at high matric potential (-0.3 MPa). Furthermore, wet sandy soil was associated with greater cadaver decomposition than wet fine-textured soil. We conclude that gravesoil moisture content can modify the relationship between temperature and cadaver decomposition and that soil microorganisms can play a significant role in cadaver breakdown. We also conclude that soil NRN is a more reliable indicator of gravesoil than soil p

  12. Predicting Selenite Adsorption by Soils Using Soil Chemical Parameters in the Constant Capacitance Model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The constant capacitance model, a chemical surface complexation model, was applied to selenite, Se(IV), adsorption on 36 soils selected for variation in soil chemical properties. The constant capacitance model was able to fit Se(IV) adsorption by optimizing one monodentate Se(IV) surface complexati...

  13. SOIL PHYSICOCHEMICAL PARAMETERS AFFECTING METAL AVAILABILITY IN SLUDGE-AMENDED SOILS

    EPA Science Inventory

    A series of laboratory studies was conducted to determine the effects of soil pH and redox potential onlevels of trace metals (Cu, Zn, Cd, Pb, Cr, Ni, and As) in selected chemical forms and their availability to plants. This research demonstrates the important effects of soil red...

  14. [Hyperspectral parameters and prediction model of soil moisture in coastal saline].

    PubMed

    Li, Chen; Zhang, Guo-wei; Zhou, Zhi-guo; Zhao, Wen-qing; Meng, Ya-li; Chen, Bing-lin; Wang, You-hua

    2016-02-01

    Based on the data of soil moisture content and indoor soil surface spectral reflectance from five sampling sites of coastal saline soil, this paper analyzed the relationship between soil moisture content and soil spectrum in wavelength 350-2500 nm. We determined spectral parameters under ratio spectral index (RSI), normalized difference spectral index (NDSI) and difference spectral index (DI), and established the quantitative model of soil moisture content. The results showed significant negative correlation between spectral reflectance and soil moisture content, and the maximum negative correlation was near 1930 nm (r=0.86). By comparison of the regression equation of RSI, NDSI and DI, it was found that the regression equation of exponential function (y=0.00001e9.7203x) built by soil moisture content based on RSI (R1407, R1459) presented the maximum R2 (0.780) and the minimum SE (0.016). The established model based on RSI (R1407, R1459) could be used to monitor soil moisture content accurately in Jiangsu coastal saline soils. PMID:27396127

  15. Model structure and parameter identification in soil carbon models using incubation data

    NASA Astrophysics Data System (ADS)

    Sierra, Carlos

    2015-04-01

    Models of soil organic matter dynamics play an important role in integrating different sources of information and help to predict future behavior of carbon stocks and fluxes in soils. In particular, compartment-based models have proved successful at integrating data from laboratory and field experiments to estimate the range of cycling rates of organic matter found in different soils. Complex models with particular mechanisms explaining processes related to the stabilization and destabilization of organic matter usually include a large number of parameters than simpler models that omit detailed mechanisms. This poses a challenge to parameterize complex models. Depending on the type of data available, the estimation of parameters in complex models may lead to identifiability problems, i.e. obtaining different combinations of parameters that give equally good predictions in relation to the observed data. In this contribution, I explore the problem of identifiability in soil organic matter models, pointing out combinations of empirical data and model structure that can minimize identifiability issues. In particular, I will show how common datasets from incubation experiments can only help to uniquely identify small number of parameters for simple models. Isotopic data and soil fractionations can help to reduce identifiability issues, but only to a limited extend. In medium-complexity models including stabilization and destabilization mechanisms, only up to 4 to 5 parameters may be uniquely identified when a full set of respiration fluxes, stocks, fractions and isotopic data are integrated to inform parameter estimation.

  16. Gas Transport Parameters for Landfill Cover Soils: Effects of Soil Compaction and Water Blockages

    NASA Astrophysics Data System (ADS)

    Wickramarachchi, P. N.; Hamamoto, S.; Kawamoto, K.; Nawagamuwa, U.; Komatsu, T.; Moldrup, P.

    2009-12-01

    Recently, landfill sites have been emerging in greenhouse warming scenarios as a significant source of atmospheric CH4. landfill management strategies have mainly addressed the problem of preventing groundwater contamination and reduction of leachate generation. Being one of the largest source of anthropogenic CH4 emission , the final cover system should also be designed for minimizing the biogas migration into the atmosphere or the areas surrounding the landfill. Compared to the intensive research efforts on hydraulic performances of landfill final cover soil , there are few studies about gas transport characteristics of landfill cover soils. Therefore, the effects of soil physical properties such as bulk density (i.e., compaction level), soil particle size and water blockage effects on the gas exchange in t highly compacted final cover soil are largely unknown. The gas exchange through the final cover soils is controlled by advective and diffusive gas transport. Air permeability (ka) governs the advective gas transport while the soil-gas diffusion coefficient (Dp) governs diffusive gas transport . In this study, the effects of compaction level and water blockage effects on ka and Dp for two landfill final cover soils were investigated. The disturbed soil samples were taken from landfill final covers in Japan and Sri Lanka. A compaction tests were performed for the soil samples with two different size fractions (< 35 mm and < 2.0 mm). In the compaction tests at field water content , the soil samples were repacked into soil cores (i.d. 15-cm, length 12-cm) at two different compaction levels (2700 kN/m2 and 600 kN/m2). After the compaction tests, ka and Dp were measured and then samples were saturated and subsequently drained at different soil-water matric potential (pF; pF equals to log(-ɛ) where ɛ is soil-water matric potential in cm H2O) of 1.5, 2.0, 3.0, 4.1, and with air-dried (pF 6.0) and oven-dried (pF 6.9) conditions. Results showed that measured Dp values

  17. Land surface scheme conceptualisation and parameter values for three sites with contrasting soils and climate

    NASA Astrophysics Data System (ADS)

    Soet, M.; Ronda, R. J.; Stricker, J. N. M.; Dolman, A. J.

    The objective of the present study is to test the performance of the ECMWF land surface module (LSM) developed by Viterbo and Beljaars (1995) and to identify primary future adjustments, focusing on the hydrological components. This was achieved by comparing off-line simulations against observations and a detailed state-of-the-art model over a range of experimental conditions. Results showed that the standard LSM, which uses fixed vegetation and soil parameter values, systematically underestimated evapotranspiration, partly due to underestimating bare soil evaporation, which appeared to be a conceptual problem. In dry summer conditions, transpiration was seriously underestimated. The bias in surface runoff and percolation was not of the same sign for all three locations. A sensitivity analysis, set up to explore the impact of using standard parameter values, found that implementing specific soil hydraulic properties had a significant effect on runoff and percolation at all three sites. Evapotranspiration, however affected only slightly at the temperate humid climate sites. Under semi-arid conditions, introducing site specific soil hydraulic properties plus a realistic rooting depth improved simulation results considerably. Future adjustments to the standard LSM should focus on parameter values of soil hydraulic functions and rooting depths and, conceptually, on the bare soil evaporation parameterisation and the soil bottom boundary condition. Implications of changing soil hydraulic properties for future large-simulations were explored briefly. For Europe, soil data requirements can be fulfilled partly by the recent data base HYPRES. Sandy and loamy sand soils will then cover about 65% of Europe, whereas in the present model 100% of the area is loam.

  18. Potassium Quantity-Intensity Parameters and its Correlation with Selected Soil Properties in Some Soils of Iran

    NASA Astrophysics Data System (ADS)

    Abaslou, H.; Abtahi, A.

    Potassium exchange-equilibrium were obtained from quantity-intensity (Q/I) isotherms, i.e., K equilibrium activity ratio (AR0k), K labile (Klab), equilibrium potential buffering capacity for k (PBCkequ), free energy of k replishment (-ΔGkequ), the Gapon selectively coefficient (kG), least soil exchangeable potassium (Emin) and initial equilibrium concentration solution potassium (C, k0). Characterization of these relations provides general information on the nature of K equilibrium and surve as a good index of K supplying power of soil. Plant availability of soil potassium is controlled by dynamic interactions among its different pools. Misunderstanding of these dynamics leads to mismanagement of soil fertility. These relationships were investigated in some selected soils of Fars province, Iran. K equilibrium activity ratio (AR0k) ranged between 1.74 to 19.90 (mmol dm-3)0.5, labile K values fluctuated within the range 1.28 to -9.78 meq 100 g-1 soil. And equilibrium potential buffering capacity (PBCkequ) fluctuated from 31.14 to 100.64 meq 100 g-1 (mmol dm-3)0.5. Potassium was significantly controlled by soil properties. Potassium activity was controlled more by silt (r = 0.80**), Mn-BCD (r = 0.67*), Mn-OX (r = 0.73*) and the -ΔGkequ values had significantly correlated with silt (r = 0.79*), Mn- BCD (r = 0.68*) Mn-OX (r = 0.71*). This result implies that studies of potassium dynamics of soils should additionally consider the level of Fe and especially Mn, as well. The Q/I parameters provide useful information for understanding K+ availability in calcareous soils and can be used for K+ fertilizer recommendations.

  19. Improved Artificial Neural Network-Pedotransfer Functions (ANN-PTFs) for Estimating Soil Hydraulic Parameters

    NASA Astrophysics Data System (ADS)

    Gautam, M. R.; Zhu, J.; Ye, M.; Meyer, P. D.; Hassan, A. E.

    2008-12-01

    ANN-PTFs have become popular means of mapping easily available soil data into hard-to-measure soil hydraulic parameters in the recent years. These parameters and their distributions are the indispensable inputs to subsurface flow and transport models which provide basis for environmental planning, management and decision making. While improved ANN prediction together with the preservation of probability distributions of hydraulic parameters in ANN training is important, ANN-PTFs have been typically found using conventional ANN training approach with the mean square error as an error function, which may not preserve the probability distribution of the parameters. Moreover, the conventional ANN training can itself introduce correlation among predicted parameters and could not preserve the actual correlation among the measured parameters. The present study describes approaches to deal with such shortcomings of conventional ANN- PTF training algorithms by using new types of error functions and presents a group of improved ANN-PTF models developed on the basis of the new approaches with different levels of data availability. In the study, the bootstrap method is used as part of ANN-PTF development for generating independent training and validation sets, and calculating uncertainty estimates of the ANN predictions. The results demonstrate the merit of the new approaches of the ANN training and the physical significance of various types of less costly soil data in the prediction of soil hydraulic parameters.

  20. Main Parameters of Soil Quality and it's Management Under Changing Climate

    NASA Astrophysics Data System (ADS)

    László Phd, M., ,, Dr.

    2009-04-01

    byproducts and atmospheric deposition; 4. storing and cycling nutrients and other elements within the earth's biosphere; and 5. providing support of socioeconomic structures and protection for archeological treasures associated with human habitation. No soil is likely to successfully provide all of these functions, some of which occur in natural ecosystems and some of which are the result of human modification. We can summarize by saying that soil quality depends on the extent to which soil functions to benefit humans. Thus, for food production or mediation of contamination, soil quality means the extent to which a soil fulfills the role we have defined for it. Within agriculture, high quality equates to maintenance of high productivity without significant soil or environmental degradation. The Glossary of Soil Science terms produced by the Soil Science Society of America (1996) states that soil quality is an inherent attribute of a soil that is inferred from soil characteristics or indirect observations. To proceed from a dictionary definition to a measure of soil quality, a minimum dataset (MDS) of soil characteristics that represents soil quality must be selected and quantified (Papendick et al., 1995). The MDS may include biological, chemical or physical soil characteristics [Organic matter (OM), Aggregation (A), Bulk density (BD), Depth to hardpan (DH), Electrical conductivity (EC), Fertility (F), Respiration (R), pH, Soil test (ST), Yield (Y), Infiltration (I), Mineralizable nitrogen potential (MNP), Water holding capacity (WHC)]. For agriculture, the measurement of properties should lead to a relatively simple and accurate way to rank soils based on potential plant production without soil degradation. Unfortunately, commonly identified soil quality parameters may not correlate well with yield (Reganold, 1988). In the next section, we consider these four points concerning the selection and quantification of soil characteristics: 1. soil characteristics may be desirable

  1. Modeling spatial and seasonal soil moisture in a semi arid hillslope: The impact of integrating soil surface seal parameters

    NASA Astrophysics Data System (ADS)

    Sela, Shai; Svoray, Tal; Assouline, Shmuel

    2010-05-01

    Modeling hillslope hydrology and the complex and coupled reaction of runoff processes to rainfall, lies in the focus of a growing number of research studies. The ability to characterize and understand the mechanisms underlying the complex hillslope soil moisture patterns, which trigger spatially variable non linear runoff initiation, still remains a current hydrological challenge especially in ungauged catchments. In humid climates, connectivity of transient moisture patches was suggested as a unifying concept for studying thresholds for subsurface flow and redistribution of soil moisture at the hillslope scale. In semiarid areas, however, transient moisture patches control also the differentiation between evaporation and surface runoff and the ability to identify a unifying concept controlling the large variability of soil moisture at the hillslope scale remains an open research gap. At the LTER Lehavim site in the center of Israel (31020' N, 34045' E) a typical hillslope (0.115 km2) was chosen offering different aspects and a classic geomorphologic banding. The annual rainfall is 290 mm, the soils are brown lithosols and arid brown loess and the dominant rock formations are Eocenean limestone and chalk with patches of calcrete. The vegetation is characterised by scattered dwarf shrubs (dominant species Sarcopoterium spinosum) and patches of herbaceous vegetation, mostly annuals, are spread between rocks and dwarf shrubs. An extensive spatial database of soil hydraulic and environmental parameters (e.g. slope, radiation, bulk density) was measured in the field and interpolated to continuous maps using geostatistical techniques and physically based modelling. To explore the effect of soil surface sealing, Mualem and Assouline (1989) equations describing the change in hydraulic parameters resulting from soil seal formation were applied. Two simple indices were developed to describe local evaporation values and contribution of water from rock outcrops to the soil

  2. Global SMOS Soil Moisture Retrievals using the Land Parameter Retrieval Model

    NASA Astrophysics Data System (ADS)

    van der Schalie, Robin; de Jeu, Richard; Kerr, Yann; Wigneron, Jean-Pierre; Rodriguez-Fernandez, Nemesio; Alyaari, Amen; Drusch, Matthias; Mecklenburg, Susanne; Dolman, Han

    2015-04-01

    The Land Parameter Retrieval Model (LPRM) is a methodology that retrieves soil moisture from low frequency dual polarized microwave measurements and has been extensively tested on C-, X- and Ku-band frequencies. Its performance on L-band is tested here by using observations from the Soil Moisture and Ocean Salinity (SMOS) satellite. These observations have potential advantages compared to higher frequencies: a low sensitivity to cloud and vegetation contamination, an increased thermal sampling depth and a greater sensitivity to soil moisture fluctuations. These features make it desirable to add SMOS-derived soil moisture retrievals to the existing European Space Agency (ESA) long-term climatological soil moisture data record, to be harmonized with other passive microwave soil moisture estimates from the LPRM. SMOS measures brightness temperature at a range of incidence angles, different incidence angles bins (42.5°, 47.5°, 52.5° and 57.5°) were combined and tested for both ascending and descending swaths. Two SMOS LPRM algorithm parameters, the single scattering albedo and roughness, were optimized against soil moisture from MERRA-Land, ERA-Interim/Land and AMSR-E LPRM over the period of July 2010 to December 2010. The SMOS LPRM soil moisture retrievals, using the optimized parameters, were then evaluated against the latest SMOS Level 3 (L3) soil moisture product and a set of in situ networks over the period of July 2010 to December 2013. The evaluation against SMOS L3 result in very high correlations over many parts of the world (>0.85), which is in line with earlier findings when SMOS LPRM was compared to SMOS L3 over the OzNet sites in southeast Australia. This study is part of an ESA project (de Jeu et al., this conference, session CL 5.7).

  3. Assessment of soil quality parameters using multivariate analysis in the Rawal Lake watershed.

    PubMed

    Firdous, Shahana; Begum, Shaheen; Yasmin, Azra

    2016-09-01

    Soil providing a wide array of ecosystem services is subjected to quality deterioration due to natural and anthropogenic factors. Most of the soils in Pakistan have poor status of available plant nutrients and cannot support optimum levels of crop productivity. The present study statistically analyzed ten soil quality parameters in five subwatersheds (Bari Imam, Chattar, Rumli, Shahdra, and Shahpur) of the Rawal Lake. Analysis of variance (ANOVA), cluster analysis (CA), and principal component analysis (PCA) were performed to evaluate correlation in soil quality parameters on spatiotemporal and vertical scales. Soil organic matter, electrical conductivity, nitrates, and sulfates were found to be lower than that required for good quality soil. Soil pH showed significant difference (p < 0.05) in mean values at different sampling sites and sampling months indicating that it is affected and determined by land uses and seasons. Pearson correlation revealed a strong positive correlation (r = 0.437) between nitrates and organic matter. Application of principal component analysis resulted in three major factors contributing 76 % of the total variance. For factor 1, temperature, sand, silt, clay, and nitrates had the highest factor loading values (>0.75) and indicated that these were the most influential parameters of first factor or component. Cluster analysis separated five sampling sites into three statistically significant clusters: I (Shahdra-Bari Imam), II (Chattar), and III (Shahpur-Rumli). Among the five sites, Shahdra was found to have good quality soil followed by Bari Imam. The present study illustrated the usefulness of multivariate statistical approaches for the analysis and interpretation of complex datasets to understand variations in soil quality for effective watershed management. PMID:27553947

  4. Impact of pesticides on soil microbiological parameters and possible bioremediation strategies.

    PubMed

    Chowdhury, Ashim; Pradhan, Saswati; Saha, Monidipta; Sanyal, Nilanjan

    2008-03-01

    Intensive agriculture is spectacularly successful since last couple of decades due to the inputs viz; fertilizers and pesticides along with high yielding varieties. The mandate for agriculture development was to feed and adequate nutrition supply to the expanding population by side the agriculture would be entering to into new area of commercial and export orientation. The attention of public health and proper utilization natural resources are also the main issues related with agriculture development. Concern for pesticide contamination in the environment in the current context of pesticide use has assumed great importance [1]. The fate of the pesticides in the soil environment in respect of pest control efficacy, non-target organism exposure and offsite mobility has been given due consideration [2]. Kinetics and pathways of degradation depend on abiotic and biotic factors [6], which are specific to a particular pesticide and therefore find preference. Adverse effect of pesticidal chemicals on soil microorganisms [3], may affect soil fertility [4] becomes a foreign chemicals major issue. Soil microorganisms show an early warning about soil disturbances by foreign chemicals than any other parameters.But the fate and behavior of these chemicals in soil ecosystem is very important since they are degraded by various factors and have the potential to be in the soil, water etc. So it is indispensable to monitor the persistence, degradation of pesticides in soil and is also necessary to study the effect of pesticide on the soil quality or soil health by in depth studies on soil microbial activity.The removal of metabolites or degraded products should be removed from soil and it has now a day's primary concern to the environmentalist. Toxicity or the contamination of pesticides can be reduced by the bioremediation process which involves the uses of microbes or plants. Either they degrade or use the pesticides by various co metabolic processes. PMID:23100705

  5. 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.

  6. Gas Transport Parameters for Landfill Final Cover Soil: Measurements and Model Modification by Dry Bulk Density

    NASA Astrophysics Data System (ADS)

    Wickramarachchi, P. N.; Kawamoto, K.; Hamamoto, S.; Nagamori, M.; Moldrup, P.; Komatsu, T.

    2011-12-01

    Landfill sites have been emerging in greenhouse warming scenarios as a significant source of atmospheric methane (CH4). Until recently, landfill management strategies have mainly addressed the problem of preventing groundwater contamination and reduction of leachate generation. Being one of the largest sources of anthropogenic CH4 emission, the final cover system should also be designed for minimizing the greenhouse gases migration into the atmosphere or the areas surrounding the landfill while securing the hydraulic performance. Compared to the intensive research efforts on hydraulic performances of landfill final cover soil, few studies about gas transport characteristics of landfill cover soils have been done. However, recent soil-gas studies implied that the effects of soil physical properties such as bulk density (i.e., compaction level), soil particle size are key parameters to understand landfill gaseous performance. The gas exchange through the final cover soils is controlled by advective and diffusive gas transport. Air permeability (ka) governs the advective gas transport while the soil-gas diffusion coefficient (Dp) governs diffusive gas transport. In this study, the effects of compaction level and particle size fraction effects on ka and Dp for landfill final cover soil was investigated. The disturbed soil samples were taken from landfill final cover in Japan. A compaction tests were performed for the soil samples with two different size fractions (< 35 mm and < 2.0 mm). In the compaction tests at field water content , the soil samples were repacked into soil cores (i.d. 15-cm, length 12-cm, 2120 cm3) at two different compaction levels [(MP):2700 kN/m2 and (SP):600 kN/m2]. After the compaction tests, ka and Dp were measured and then samples were saturated and subsequently drained at different soil-water matric potential of 0.98, 2.94, 9.81, 1235 kPa and with air-dried and oven-dried conditions. Results showed that measured Dp and ka values for the

  7. Quantification of parameters controlling the carbon stocks in German agricultural soils

    NASA Astrophysics Data System (ADS)

    Vos, Cora; Don, Axel; Freibauer, Annette; Heidkamp, Arne; Prietz, Roland

    2016-04-01

    Within the framework of UNFCCC, Germany is obligated to report on its greenhouse gas emissions from soils. This also includes the emissions in the agricultural sector. Changes in soil carbon stocks are a major source of CO2 that need to be reported. Until now there are only regional inventories of the soil carbon stocks in the agricultural sector while for the forestry sector a repeated national inventory exists. In order to report on changes in soil carbon stocks in agricultural soils, a consistent, representative and quantitative dataset of agricultural soil properties, especially on carbon stocks and management data is necessary. In the course of the German Agricultural Soil Inventory 3109 agricultural sites are examined. Up to January 2016, 2450 sites were sampled. The sites are sampled in five depth increments and all samples are analyzed in the same laboratory. Of the sampled sites the laboratory analyses are completed for 1312 sites. The samples of all depth increments were analyzed for their texture, bulk density, pH, electric conductivity, stone and root content, organic and inorganic carbon content and nitrogen content. The data are coupled with management data covering the past ten years and with climate data. They are analyzed with multivariate statistical techniques (e.g. mixed effects models, additive models, random forest) to quantify the parameters that control the carbon stocks in German agricultural soils. First descriptive results show that the mean soil carbon stocks down to a depth of 100 cm are 126.1 t ha‑1 (range 8.9-1158.9 t ha‑1). The mean stocks only for croplands are 102.6 t ha‑1 (range 8.9-1158.9 t ha‑1), while for grasslands the mean stock is 184.1 t ha‑1 (range 19.4-937.8 t ha‑1). In total the soil scientists found a surprisingly high proportion of disturbed and unusual soil profiles, indicating intensive human modifications of agricultural soils through e.g. deep ploughing. The data set of the German Agricultural Soil

  8. Nonlinear soil parameter effects on dynamic embedment of offshore pipeline on soft clay

    NASA Astrophysics Data System (ADS)

    Yu, Su Young; Choi, Han Suk; Lee, Seung Keon; Park, Kyu-Sik; Kim, Do Kyun

    2015-06-01

    In this paper, the effects of nonlinear soft clay on dynamic embedment of offshore pipeline were investigated. Seabed embedment by pipe-soil interactions has impacts on the structural boundary conditions for various subsea structures such as pipeline, riser, pile, and many other systems. A number of studies have been performed to estimate real soil behavior, but their estimation of seabed embedment has not been fully identified and there are still many uncertainties. In this regards, comparison of embedment between field survey and existing empirical models has been performed to identify uncertainties and investigate the effect of nonlinear soil parameter on dynamic embedment. From the comparison, it is found that the dynamic embedment with installation effects based on nonlinear soil model have an influence on seabed embedment. Therefore, the pipe embedment under dynamic condition by nonlinear parameters of soil models was investigated by Dynamic Embedment Factor (DEF) concept, which is defined as the ratio of the dynamic and static embedment of pipeline, in order to overcome the gap between field embedment and currently used empirical and numerical formula. Although DEF through various researches is suggested, its range is too wide and it does not consider dynamic laying effect. It is difficult to find critical parameters that are affecting to the embedment result. Therefore, the study on dynamic embedment factor by soft clay parameters of nonlinear soil model was conducted and the sensitivity analyses about parameters of nonlinear soil model were performed as well. The tendency on dynamic embedment factor was found by conducting numerical analyses using OrcaFlex software. It is found that DEF was influenced by shear strength gradient than other factors. The obtained results will be useful to understand the pipe embedment on soft clay seabed for applying offshore pipeline designs such as on-bottom stability and free span analyses.

  9. Employing satellite retrieved soil moisture for parameter estimation of the hydrologic model mHM

    NASA Astrophysics Data System (ADS)

    Zink, Matthias; Mai, Juliane; Rakovec, Oldrich; Schrön, Martin; Kumar, Rohini; Schäfer, David; Samaniego, Luis

    2016-04-01

    Hydrological models are usually calibrated against observed streamflow at the catchment outlet and thus they are conditioned by an integral catchment signal. Rakovec et al. 2016 (JHM) recently demonstrated that constraining model parameters against river discharge is a necessary, but not a sufficient condition. Such a procedure ensures the fulfillment of the catchment's water balance but can lead to high predictive uncertainties of model internal states, like soil moisture, or a lack in spatial representativeness of the model. However, some hydrologic applications, as e.g. soil drought monitoring and prediction, rely on this information. Within this study we propose a framework in which the mesoscale Hydrologic Model (mHM) is calibrated with soil moisture retrievals from various sources. The aim is to condition the model on soil moisture (SM), while preserving good performance in streamflow estimation. We identify the most appropriate objective functions by conducting synthetic experiments. The best objective function is determined based on: 1) deviation between synthetic and simulated soil moisture, 2) nonparametric comparison of SM fields (e.g. copulas), and 3) by euclidian distance of model parameters, which is zero if the parameters of the synthetic data are recovered. Those objective functions performing best are used to calibrate mHM against different satellite soil moisture products, e.g. ESA-CCI, H-SAF, and in situ observations. This procedure is tested in three distinct European basins (upper Sava, Neckar, and upper Guadalquivir basin) ranging from snow domination to semi arid climatic conditions. Results obtained with the synthetic experiment indicate that objective functions focusing on the temporal dynamics of SM are preferable to objective functions aiming at spatial patterns or catchment averages. Since the deviation of soil moisture fields (1) and their copulas (2) don't lead to conclusive results, the decision of the best performing objective

  10. Georeferenced database on soil and air climate parameters of Russia and its cartographic implications

    NASA Astrophysics Data System (ADS)

    Alyabina, Irina; Reshotkin, Oleg; Konyushkov, Dmitry; Khudyakov, Oleg

    2014-05-01

    Many theoretical and applied problems related to the assessment of ecosystem response to climate changes imply simultaneous analysis of data on air and soil climate. In particular, soil temperature is a very important characteristic allowing us to judge sensitivity of ecosystems to climatic fluctuations and anthropogenic impacts. It is also of great importance for predicting the functioning of terrestrial biocenoses, geocryological and engineering conditions of the territory, etc. The vast territory of Russia is characterized by the great diversity of soil climatic conditions and by differently directed tendencies of their recent changes. A combined study of the spatial and temporal changes in the parameters of soil and atmospheric climates of Russia and their cartographic modeling are of great interest. Russia has a well-developed network of weather stations, at which measurements of soil temperatures at standard depths have been performed using the same methods for more than a century. The analysis of these data with the use of geographic information systems seems to be promising. For this purpose, a georeferenced database on the parameters of soil and atmospheric climate is being developed. Such a database in the GIS environment makes it possible to develop a system of cartographic models of the climate of Russian soils, including data on the climatic norm (1960-1990) and on its changes in the recent decades. This system will be used for assessing soil climatic conditions in the subjects of the Russian Federation and in separate soil-geographic provinces. A series of small-scale preliminary maps of soil temperature parameters was included in the National Soil Atlas of the Russian Federation (2011). These maps indicate that the mean annual soil temperature in Russia varies from -14.5 to +15.2ºC, and the accumulated daily temperatures >10ºC increase in the southward direction from 0 to 4800ºC (degree-days). The duration of the period with soil temperatures >10

  11. Uncertainty related to input parameters of (137)Cs soil redistribution model for undisturbed fields.

    PubMed

    Iurian, Andra-Rada; Mabit, Lionel; Cosma, Constantin

    2014-10-01

    This study presents an alternative method to empirically establish the effective diffusion coefficient and the convective velocity of (137)Cs in undisturbed soils. This approach offers the possibility to improve the parameterisation and the accuracy of the (137)Cs Diffusion and Migration Model (DMM) used to assess soil erosion magnitudes. The impact of the different input parameters of this radiometric model on the derived-soil redistribution rates has been determined for a Romanian pastureland located in the northwest extremity of the Transylvanian Plain. By fitting the convection-diffusion equation to the available experimental data, the diffusion coefficient and convection velocity of (137)Cs in soil could be determined; 72% of the (137)Cs soil content could be attributed to the (137)Cs fallout originating from Chernobyl. The medium-term net erosion rate obtained with the calculated input parameters reached -6.6 t ha(-1) yr(-1). The model highlights great sensitivity to parameter estimations and the calculated erosion rates for undisturbed landscapes can be highly impacted if the input parameters are not accurately determined from the experimental data set. Upper and lower bounds should be established based on the determined uncertainty budget for the reliable estimates of the derived redistribution rates. PMID:24929506

  12. Vertisols with Gilgai Microtopography: Classification and Parameters of Microtopography and Morphological Types of Soils (a Review)

    NASA Astrophysics Data System (ADS)

    Khitrov, N. B.

    2016-02-01

    Data on clayey swelling soils with gilgai microtopography are systematized. Classifications of gilgai microtopography representing regularly alternating microhighs and microlows are discussed, and its geometric parameters under different landscape conditions are considered. Gilgai microtopography is developed within flat or slightly inclined elements of the mesorelief composed of swelling clays of different geneses. These materials are characterized by the high swelling-shrinking capacity upon wetting-drying cycles owing to the predominance of clay minerals of smectitic group. These processes are especially pronounced under conditions of the impeded surface drainage and contrasting of the wet seasons with strong soil moistening by atmospheric precipitation or surface water and the seasons with deep soil drying under the impact of physical evaporation and transpiration. The areas with gilgai microtopography have complex soil cover patterns composed of Vertisols and vertic soils. Their formation is related to lateral movements of solid material in the soil profiles and along the curved soil surface. The morphological types of soil complexes in such area are systematized.

  13. The influence of selecting the correlation model on soil parameters and bearing capacity

    NASA Astrophysics Data System (ADS)

    Pieczynska-Kozlowska, Joanna M.

    2016-04-01

    Consideration of soil spatial variability in the geotechnical design is still marginalized. The design process is based on taking the average parameters, which often results the oversize of geotechnical constructions. This procedure works until there are no geotechnical design problems. In most cases, geotechnical constructions represent a small percentage of the total investment so effects lacking developed of optimization procedures. If the optimization is needed requires the most accurate mapping of the soil. The basic background for statistical interpretation of soil spatially variables are Cone Penetration Tests, which represents variable nature of the soil with depth. Assuming the soil structure as a spatially random variable can be applied by description based on random fields. Field parameters are the probability distribution and correlation model dependent of a scale of fluctuation estimated from CPT. The main goal of this study is to contribute to the understanding on how the choice of correlation model affects random soil properties and for example shallow foundation bearing capacity. The study is particularly focused on scale of fluctuation as related to the reduction of bearing capacity. Scale of fluctuation were estimated using two effective methods: Vanmarcke and Rice. Soil properties were analyzed from 12 Cone Penetration Tests distributed throughout the regions of Świebodzice (Lower Silesia, Poland). While the project was developed in hilly terrain the macrolevelling were taken involving the displacement of native soil mass to form a working platform for shallow foundation. The construction of embankment has been tested by cone resistance tests to determine the parameters for the design. The procedure adopted to this study include the modeling soil variability from the CPT results and calculate the bearing capacity of shallow foundation using random finite element method and different correlation models. The aim of study was to answer questions

  14. On the Influence of Topography Upon Scaling Characteristics of Soil Hydraulic Parameters

    NASA Astrophysics Data System (ADS)

    Jana, R. B.; Mohanty, B. P.

    2008-12-01

    One of the most important issues concerning studies into the hydrologic cycle and climate prediction today is the upscaling of soil hydraulic parameters in the unsaturated zone. Ecological phenomena occur differently, and due to different causes, at a wide range of scales. Efforts to model hydrologic processes and phenomena, with particular emphasis on those occurring in the unsaturated zone, are currently ongoing at various scales. Input data are required for these models at their representative scales. However, measurement of parameter data at all such required scales is impractical as it entails huge outlay of finances, time and effort. Inter-connections often exist between information across these scales. However, the exact mathematical or physical nature of these connections is generally a mystery. Over the past few decades, numerous efforts have been conducted to either understand and solve these mysteries, or to find a way around them to obtain effective parameters at multiple scales. Most upscaling efforts thus far have opted to ignore the effect of topography in their derivation of effective parameter values. This approach is reasonable as long as the coarser support dimensions are smaller than hill slopes. When upscaling fine scale hydraulic parameter data to hillslope scales and beyond, however, topography plays a bigger role and cannot be ignored. We present a study of the influence of topographic variations on the effective, upscaled soil hydraulic parameters under different hillslope configurations. Fine resolution parameters were upscaled using the Power Averaging Operator methodology which incorporates features from both mean-type and mode-type aggregation. Simulations of multiple hypothetical scenarios were conducted using the HYDRUS- 3D hydrologic modeling software to develop empirical relationships between the topography and the soil hydraulic parameters for matching hydrologic responses. These relationships may be assimilated into currently

  15. Sensitivity of soil water content simulation to different methods of soil hydraulic parameter characterization as initial input values

    NASA Astrophysics Data System (ADS)

    Rezaei, Meisam; Seuntjens, Piet; Shahidi, Reihaneh; Joris, Ingeborg; Boënne, Wesley; Cornelis, Wim

    2016-04-01

    Soil hydraulic parameters, which can be derived from in situ and/or laboratory experiments, are key input parameters for modeling water flow in the vadose zone. In this study, we measured soil hydraulic properties with typical laboratory measurements and field tension infiltration experiments using Wooding's analytical solution and inverse optimization along the vertical direction within two typical podzol profiles with sand texture in a potato field. The objective was to identify proper sets of hydraulic parameters and to evaluate their relevance on hydrological model performance for irrigation management purposes. Tension disc infiltration experiments were carried out at five different depths for both profiles at consecutive negative pressure heads of 12, 6, 3 and 0.1 cm. At the same locations and depths undisturbed samples were taken to determine the water retention curve with hanging water column and pressure extractors and lab saturated hydraulic conductivity with the constant head method. Both approaches allowed to determine the Mualem-van Genuchten (MVG) hydraulic parameters (residual water content θr, saturated water content θs,, shape parameters α and n, and field or lab saturated hydraulic conductivity Kfs and Kls). Results demonstrated horizontal differences and vertical variability of hydraulic properties. Inverse optimization resulted in excellent matches between observed and fitted infiltration rates in combination with final water content at the end of the experiment, θf, using Hydrus 2D/3D. It also resulted in close correspondence of  and Kfs with those from Logsdon and Jaynes' (1993) solution of Wooding's equation. The MVG parameters Kfs and α estimated from the inverse solution (θr set to zero), were relatively similar to values from Wooding's solution which were used as initial value and the estimated θs corresponded to (effective) field saturated water content θf. We found the Gardner parameter αG to be related to the optimized van

  16. Micro- and macro-scale petrophysical characterization of potential reservoir units from the Northern Israel

    NASA Astrophysics Data System (ADS)

    Haruzi, Peleg; Halisch, Matthias; Katsman, Regina; Waldmann, Nicolas

    2016-04-01

    Lower Cretaceous sandstone serves as hydrocarbon reservoir in some places over the world, and potentially in Hatira formation in the Golan Heights, northern Israel. The purpose of the current research is to characterize the petrophysical properties of these sandstone units. The study is carried out by two alternative methods: using conventional macroscopic lab measurements, and using CT-scanning, image processing and subsequent fluid mechanics simulations at a microscale, followed by upscaling to the conventional macroscopic rock parameters (porosity and permeability). Comparison between the upscaled and measured in the lab properties will be conducted. The best way to upscale the microscopic rock characteristics will be analyzed based the models suggested in the literature. Proper characterization of the potential reservoir will provide necessary analytical parameters for the future experimenting and modeling of the macroscopic fluid flow behavior in the Lower Cretaceous sandstone.

  17. Parameter identification and analysis of soluble chemical transfer from soil to surface runoff

    NASA Astrophysics Data System (ADS)

    Tong, J. X.; Yang, J. Z.; Hu, B. X.

    2012-03-01

    A two-layer mathematical model is used to predict the chemical transfer from the soil into the surface runoff with ponding water. There are two incomplete infiltration-related parameter γ and runoff-related parameter α in the analytical solution to the model, which were assumed to be constant in previous studies (Tong et al., 2010). In this study, experimental data are used to identify the variable γ and α based on the analytical solution. The soil depth of the mixing zone is kept to be constant in different experiments, and the values of γ and α before the surface runoff occurs are constant and equal to their values at the moment the runoff starts. From the study results, it is found that γ will decrease with the increase of the surface runoff time, the increase of the ponding-water depth, hp, or with the decrease of the initial volumetric water content. The variability of γ will decrease with the increase of the initial volumetric water content. Similarly, α will decrease with time for the initially unsaturated experimental soils, but will increase with time for the initially saturated experimental soils. The larger the infiltration, the less chemical concentration in the surface runoff is. The analytical solution is not valid for experimental soil without any infiltration if α is expected to be less or equal to 1. The results will help to quantify chemical transfer from soil into runoff, a significant problem in agricultural pollution management.

  18. Parameter Estimation And Sensitivity Analysis for Root Zone Soil Moisture in SVAT Models.

    NASA Astrophysics Data System (ADS)

    Judge, J.; Agrawal, D.; Graham, W. D.

    2008-05-01

    Accurate knowledge of root zone soil moisture is crucial in hydrology, micrometeorology and agriculture for estimating energy and moisture fluxes at the land surface. Soil Vegetation Atmosphere Transfer (SVAT) models are typically used to simulate energy and moisture transport in soil and vegetation, and estimate these fluxes at the land surface and in the vadose zone. Coupling an SVAT model with a vegetation model allows inclusion of canopy effects on the fluxes, without relying on observations or empirical functions. An SVAT model, viz. Land Surface Process (LSP) model, has been coupled with a widely used crop-growth model, Decision Support System for Agrotechnology Transfer (DSSAT). The LSP-DSSAT was calibrated for a growing season of sweet corn in North Central Florida, using extensive field observations from the second Microwave Water and Energy Balance Experiment (MicroWEX-2). In this research, we address uncertainty of parameters in the LSP-DSSAT model, due to uncertainty in forcings and initial conditions, and due to accumulated errors from numerical computation. We also conduct sensitivity analyses to identify key model parameters to which the root zone soil moisture estimates are most sensitive. We will present a stochastic approach to estimate correlations between the parameters and root zone soil moisture.

  19. Investigating the relationship between a soils classification and the spatial parameters of a conceptual catchment-scale hydrological model

    NASA Astrophysics Data System (ADS)

    Dunn, S. M.; Lilly, A.

    2001-10-01

    There are now many examples of hydrological models that utilise the capabilities of Geographic Information Systems to generate spatially distributed predictions of behaviour. However, the spatial variability of hydrological parameters relating to distributions of soils and vegetation can be hard to establish. In this paper, the relationship between a soil hydrological classification Hydrology of Soil Types (HOST) and the spatial parameters of a conceptual catchment-scale model is investigated. A procedure involving inverse modelling using Monte-Carlo simulations on two catchments is developed to identify relative values for soil related parameters of the DIY model. The relative values determine the internal variability of hydrological processes as a function of the soil type. For three out of the four soil parameters studied, the variability between HOST classes was found to be consistent across two catchments when tested independently. Problems in identifying values for the fourth 'fast response distance' parameter have highlighted a potential limitation with the present structure of the model. The present assumption that this parameter can be related simply to soil type rather than topography appears to be inadequate. With the exclusion of this parameter, calibrated parameter sets from one catchment can be converted into equivalent parameter sets for the alternate catchment on the basis of their HOST distributions, to give a reasonable simulation of flow. Following further testing on different catchments, and modifications to the definition of the fast response distance parameter, the technique provides a methodology whereby it is possible to directly derive spatial soil parameters for new catchments.

  20. Identifying mechanical property parameters of planetary soil using in-situ data obtained from exploration rovers

    NASA Astrophysics Data System (ADS)

    Ding, Liang; Gao, Haibo; Liu, Zhen; Deng, Zongquan; Liu, Guangjun

    2015-12-01

    Identifying the mechanical property parameters of planetary soil based on terramechanics models using in-situ data obtained from autonomous planetary exploration rovers is both an important scientific goal and essential for control strategy optimization and high-fidelity simulations of rovers. However, identifying all the terrain parameters is a challenging task because of the nonlinear and coupling nature of the involved functions. Three parameter identification methods are presented in this paper to serve different purposes based on an improved terramechanics model that takes into account the effects of slip, wheel lugs, etc. Parameter sensitivity and coupling of the equations are analyzed, and the parameters are grouped according to their sensitivity to the normal force, resistance moment and drawbar pull. An iterative identification method using the original integral model is developed first. In order to realize real-time identification, the model is then simplified by linearizing the normal and shearing stresses to derive decoupled closed-form analytical equations. Each equation contains one or two groups of soil parameters, making step-by-step identification of all the unknowns feasible. Experiments were performed using six different types of single-wheels as well as a four-wheeled rover moving on planetary soil simulant. All the unknown model parameters were identified using the measured data and compared with the values obtained by conventional experiments. It is verified that the proposed iterative identification method provides improved accuracy, making it suitable for scientific studies of soil properties, whereas the step-by-step identification methods based on simplified models require less calculation time, making them more suitable for real-time applications. The models have less than 10% margin of error comparing with the measured results when predicting the interaction forces and moments using the corresponding identified parameters.

  1. Soil water content and evaporation determined by thermal parameters obtained from ground-based and remote measurements

    NASA Technical Reports Server (NTRS)

    Reginato, R. J.; Idso, S. B.; Jackson, R. D.; Vedder, J. F.; Blanchard, M. B.; Goettelman, R.

    1976-01-01

    Soil water contents from both smooth and rough bare soil were estimated from remotely sensed surface soil and air temperatures. An inverse relationship between two thermal parameters and gravimetric soil water content was found for Avondale loam when its water content was between air-dry and field capacity. These parameters, daily maximum minus minimum surface soil temperature and daily maximum soil minus air temperature, appear to describe the relationship reasonably well. These two parameters also describe relative soil water evaporation (actual/potential). Surface soil temperatures showed good agreement among three measurement techniques: in situ thermocouples, a ground-based infrared radiation thermometer, and the thermal infrared band of an airborne multispectral scanner.

  2. Modeling soil parameters using hyperspectral image reflectance in subtropical coastal wetlands

    NASA Astrophysics Data System (ADS)

    Anne, Naveen J. P.; Abd-Elrahman, Amr H.; Lewis, David B.; Hewitt, Nicole A.

    2014-12-01

    Developing spectral models of soil properties is an important frontier in remote sensing and soil science. Several studies have focused on modeling soil properties such as total pools of soil organic matter and carbon in bare soils. We extended this effort to model soil parameters in areas densely covered with coastal vegetation. Moreover, we investigated soil properties indicative of soil functions such as nutrient and organic matter turnover and storage. These properties include the partitioning of mineral and organic soil between particulate (>53 μm) and fine size classes, and the partitioning of soil carbon and nitrogen pools between stable and labile fractions. Soil samples were obtained from Avicennia germinans mangrove forest and Juncus roemerianus salt marsh plots on the west coast of central Florida. Spectra corresponding to field plot locations from Hyperion hyperspectral image were extracted and analyzed. The spectral information was regressed against the soil variables to determine the best single bands and optimal band combinations for the simple ratio (SR) and normalized difference index (NDI) indices. The regression analysis yielded levels of correlation for soil variables with R2 values ranging from 0.21 to 0.47 for best individual bands, 0.28 to 0.81 for two-band indices, and 0.53 to 0.96 for partial least-squares (PLS) regressions for the Hyperion image data. Spectral models using Hyperion data adequately (RPD > 1.4) predicted particulate organic matter (POM), silt + clay, labile carbon (C), and labile nitrogen (N) (where RPD = ratio of standard deviation to root mean square error of cross-validation [RMSECV]). The SR (0.53 μm, 2.11 μm) model of labile N with R2 = 0.81, RMSECV= 0.28, and RPD = 1.94 produced the best results in this study. Our results provide optimism that remote-sensing spectral models can successfully predict soil properties indicative of ecosystem nutrient and organic matter turnover and storage, and do so in areas with dense

  3. Parameters of microbial respiration in soils of the impact zone of a mineral fertilizer factory

    NASA Astrophysics Data System (ADS)

    Zhukova, A. D.; Khomyakov, D. M.

    2015-08-01

    The carbon content in the microbial biomass and the microbial production of CO2 (the biological component of soil respiration) were determined in the upper layer (0-10 cm) of soils in the impact zone of the OJSC Voskresensk Mineral Fertilizers, one of the largest factories manufacturing mineral fertilizers in Russia. Statistical characteristics and schematic distribution of the biological parameters in the soil cover of the impact zone were analyzed. The degree of disturbance of microbial communities in the studied objects varied from weak to medium. The maximum value (0.44) was observed on the sampling plot 4 km away from the factory and 0.5 km away from the place of waste (phosphogypsum) storage. Significantly lower carbon content in the microbial biomass and its specific respiration were recorded in the agrosoddy-podzolic soil as compared with the alluvial soil sampled at the same distance from the plant. The effects of potential soil pollutants (fluorine, sulfur, cadmium, and stable strontium) on the characteristics of soil microbial communities were described with reliable regression equations.

  4. Thermal analysis to derive energetic quality parameters of soil organic matter?

    NASA Astrophysics Data System (ADS)

    Peikert, Benjamin; Schaumann, Gabriele Ellen

    2014-05-01

    Many studies have dealt with thermal analysis for characterisation of soil and soil organic matter. It is a versatile tool assessing various physicochemical properties of the sample during heating and/or cooling. Especially the combination of different detection methods is highly promising. In this contribution, we will discuss the combination of thermogravimetry (TGA) with differential scanning calorimetry (DSC) in one single thermal analysis device. TGA alone helps distinguishment of soil and soil organic matter fractions with respect to their resistance towards combustion and allows a quantitative assignment of thermolabile and recalcitrant OM fractions. Combination with DSC in the same device, allows determination of energy transformation during the combustion process. Therefore, it becomes possible to determine not only the calorific value of the organic matter, but also of its fractions. We will show the potential of using the calorific values of OM fractions as quality parameter - exemplified for the analysis of soils polluted with organic matter from the olive oil production. The pollution history of these samples is largely unknown. As expected, TGA indicated a relative enrichment of the labile carbon fraction in contaminated samples with respect to the controls. The calorific values of the thermolabile and the recalcitrant fractions differ from each other, and those of the recalcitrant fractions of the polluted samples were higher than of those of the unpolluted controls. Further analyses showed correlation of the calorific value of this fraction with soil water repellency and the carbon isotopic ratio. The synthesis of our current data suggests that the content of thermolabile fraction, the isotopic ratio and calorific value of the recalcitrant fraction are useful indicators for characterizing the degree of decomposition of OMW organic matter. In this contribution, we will further discuss the potential of using the energetic parameters a quality

  5. Modeling oxyanion adsorption on ferralic soil, part 1: parameter validation with phosphate ion.

    PubMed

    Pérez, Claudio; Antelo, Juan; Fiol, Sarah; Arce, Florencio

    2014-10-01

    Surface complexation models have proved to be valuable tools for predicting processes that occur at the solid-solution interface. Use of such models has become more widespread and nowadays more complex systems are studied, in an attempt to explain processes such as the competition between different species for mineral surfaces and the effect of the presence of organic matter. The aim of the present study was to analyze the mobility of phosphate in ferralic soils. The charge distribution model parameters for phosphate-goethite adsorption were used to predict phosphate mobility on samples from 2 horizons of a ferralic soil containing large amounts of iron oxides. The soil reactivity was attributed to the iron oxides, and some specific parameters were determined by means of phosphate adsorption-desorption experiments and included in the model. Adsorption of phosphate in the upper horizon, which contained more organic carbon and phosphate than the deeper one, was modeled by using the information obtained for the soil and the charge distribution model parameters derived for phosphate-goethite interaction with no need of further optimization. In contrast, some extra fitting parameters were required to improve the modeling of the phosphate adsorption in the deeper horizon. PMID:24838985

  6. Field-Scale soil moisture assimilation: State, parameter or bias estimation?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Observations can be used to constrain model parameters (calibration), model state variables (state updating,initialization), model error (bias estimation, error characterization) or any combination thereof. It is studied how soil moisture profile observations are best exploited with Community Land M...

  7. No-Till Management Effects on Soil Water and Wind Erodibility Parameters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The extent to which no-till management improves water and wind erodibility parameters is not well understood. This study assessed changes in aggregate resistance to raindrops, dry aggregate wettability, and dry aggregate stability as well as their relationships with changes in soil organic carbon co...

  8. EFFECTS OF ACID PRECIPITATION ON MICROBIOLOGICAL AND CHEMICAL PARAMETERS IN SOILS: THE FLORIDA EXPERIENCE

    EPA Science Inventory

    The effects of acid precipitation on microbiological and chemical parameters in soils were investigated under field conditions. The study site consisted of three transects, each including three 75 sq. m. plots. One transect served as a control, the second one was irrigated with a...

  9. Scaling Parameters of the Lewis-Kostiakov Water Infiltration Equation Across Soil Textural Classes and Extension to Rain Infiltration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A recent study showed that the Brooks-Corey equation parameters for soil hydraulic properties were strongly correlated to the pore-size distribution index (lambda), the slope of the log-log soil moisture characteristic curve across eleven soil textural classes from sand to clay. It further showed th...

  10. Inverse estimation of parameters for multidomain flow models in soil columns with different macropore densities

    PubMed Central

    Arora, Bhavna; Mohanty, Binayak P.; McGuire, Jennifer T.

    2013-01-01

    Soil and crop management practices have been found to modify soil structure and alter macropore densities. An ability to accurately determine soil hydraulic parameters and their variation with changes in macropore density is crucial for assessing potential contamination from agricultural chemicals. This study investigates the consequences of using consistent matrix and macropore parameters in simulating preferential flow and bromide transport in soil columns with different macropore densities (no macropore, single macropore, and multiple macropores). As used herein, the term“macropore density” is intended to refer to the number of macropores per unit area. A comparison between continuum-scale models including single-porosity model (SPM), mobile-immobile model (MIM), and dual-permeability model (DPM) that employed these parameters is also conducted. Domain-specific parameters are obtained from inverse modeling of homogeneous (no macropore) and central macropore columns in a deterministic framework and are validated using forward modeling of both low-density (3 macropores) and high-density (19 macropores) multiple-macropore columns. Results indicate that these inversely modeled parameters are successful in describing preferential flow but not tracer transport in both multiple-macropore columns. We believe that lateral exchange between matrix and macropore domains needs better accounting to efficiently simulate preferential transport in the case of dense, closely spaced macropores. Increasing model complexity from SPM to MIM to DPM also improved predictions of preferential flow in the multiple-macropore columns but not in the single-macropore column. This suggests that the use of a more complex model with resolved domain-specific parameters is recommended with an increase in macropore density to generate forecasts with higher accuracy. PMID:24511165

  11. Role and development of soil parameters for seismic responses of buried lifelines

    SciTech Connect

    Wang, L.R.L.

    1983-01-01

    Buried lifelines, e.g. oil, gas, water and sewer pipelines have been damaged heavily in recent earthquakes such as 1971 San Fernando Earthquake, in U.S.A., 1976 Tangshan Earthquake, in China, and 1978 MiyagiKen-Oki Earthquake, in Japan, among others. Researchers on the seismic performance of these buried lifelines have been initiated in the United States and many other countries. Various analytical models have been proposed. However, only limited experimental investigations are available. The sources of earthquake damage to buried lifelines include landslide, tectonic uplift-subsidence, soil liquefaction, fault displacement and ground shaking (effects of wave propagation). This paper is concerned with the behavior of buried lifeline systems subjected to surface faulting and ground shaking. The role and development of soil parameters that significantly influence the seismic responses are discussed. The scope of this paper is to examine analytically the influence of various soil and soilstructure interaction parameters to the seismic responses of buried pipelines, to report the currently available physical data of these and related parameters for immediate applications, and to describe the experiments to obtain additional information on soil resistant characteristics to longitudinal pipe motions.

  12. Applicability of Different Hydraulic Parameters to Describe Soil Detachment in Eroding Rills

    PubMed Central

    Wirtz, Stefan; Seeger, Manuel; Zell, Andreas; Wagner, Christian; Wagner, Jean-Frank; Ries, Johannes B.

    2013-01-01

    This study presents the comparison of experimental results with assumptions used in numerical models. The aim of the field experiments is to test the linear relationship between different hydraulic parameters and soil detachment. For example correlations between shear stress, unit length shear force, stream power, unit stream power and effective stream power and the detachment rate does not reveal a single parameter which consistently displays the best correlation. More importantly, the best fit does not only vary from one experiment to another, but even between distinct measurement points. Different processes in rill erosion are responsible for the changing correlations. However, not all these procedures are considered in soil erosion models. Hence, hydraulic parameters alone are not sufficient to predict detachment rates. They predict the fluvial incising in the rill's bottom, but the main sediment sources are not considered sufficiently in its equations. The results of this study show that there is still a lack of understanding of the physical processes underlying soil erosion. Exerted forces, soil stability and its expression, the abstraction of the detachment and transport processes in shallow flowing water remain still subject of unclear description and dependence. PMID:23717669

  13. Applicability of different hydraulic parameters to describe soil detachment in eroding rills.

    PubMed

    Wirtz, Stefan; Seeger, Manuel; Zell, Andreas; Wagner, Christian; Wagner, Jean-Frank; Ries, Johannes B

    2013-01-01

    This study presents the comparison of experimental results with assumptions used in numerical models. The aim of the field experiments is to test the linear relationship between different hydraulic parameters and soil detachment. For example correlations between shear stress, unit length shear force, stream power, unit stream power and effective stream power and the detachment rate does not reveal a single parameter which consistently displays the best correlation. More importantly, the best fit does not only vary from one experiment to another, but even between distinct measurement points. Different processes in rill erosion are responsible for the changing correlations. However, not all these procedures are considered in soil erosion models. Hence, hydraulic parameters alone are not sufficient to predict detachment rates. They predict the fluvial incising in the rill's bottom, but the main sediment sources are not considered sufficiently in its equations. The results of this study show that there is still a lack of understanding of the physical processes underlying soil erosion. Exerted forces, soil stability and its expression, the abstraction of the detachment and transport processes in shallow flowing water remain still subject of unclear description and dependence. PMID:23717669

  14. Investigation of parameters controlling the soil sink of atmospheric molecular hydrogen

    NASA Astrophysics Data System (ADS)

    Schmitt, S.; Hanselmann, A.; Wollschläger, U.; Hammer, S.; Levin, I.

    2009-04-01

    Enclosure measurements have been performed on a bare mineral soil at an experimental field site near Heidelberg, Germany. From observed molecular hydrogen (H2) mixing ratio changes in the enclosure, deposition velocities were calculated ranging from 8.4 × 10-3 to 8.2 × 10-2cms-1 and with an annual mean value of 3.1 × 10-2cms-1. In the studied range of 2- 27°C, the uptake showed a significant temperature dependence. However, this turned out not to be the primary driving mechanism of the uptake flux. Soil moisture content, co-varying with temperature, was identified as the major parameter being responsible for the diffusive permeability of H2 in the soil and the final rate of H2 uptake. A simple Millington-Quirk diffusion model approach could largely explain this behaviour and yielded a diffusion path length of H2 in the studied soil of only 0.2-1.8cm, suggesting that total H2 consumption occurs within the first few centimetres of the soil. The diffusion model, when applied to continuous measurements of soil moisture content, atmospheric pressure, temperature and the mixing ratio of H2 in the atmosphere, could largely reproduce the measured deposition flux densities, assuming a mean thickness of the diffusion path length of 0.7cm.

  15. Changes in soil parameters under continuous plastic mulching in strawberry cultivation

    NASA Astrophysics Data System (ADS)

    Muñoz, Katherine; Diehl, Dörte; Scopchanova, Sirma; Schaumann, Gabriele E.

    2016-04-01

    Plastic mulching (PM) is a widely used practice in modern agriculture because they generate conditions for optimal yield rates and quality. However, information about long-term effects of PC on soil quality parameters is scarce. The aim of this study is to compare the effect of three different mulching managements on soil quality parameters. Sampling and methodology: Three different managements were studied: Organic mulching (OM), 2-years PM and 4-years PM. Soil samples were collected from irrigated fields in 0-5, 5-10 and 10-30 cm depths and analyzed for water content (WC), pH, dissolved organic carbon (DOC), total soil carbon (Ctot) and cation exchange capacity (CECeff). Results and discussion: Mulching management has an influence on soil parameters. The magnitude of the effects is influenced by the type (organic agriculture practice vs. plastic mulching practice) and duration of the mulching. PM modified the water distribution through the soil column. WC values at the root zone were in average 10% higher compared to those measured at the topsoil. Under OM, the WC was lower than under PM. The pH was mainly influenced by the duration of the managements with slightly higher values after 4 than after 2-years PM. Under PM, aqueous extracts of the topsoil (0-5 cm depth) contained in average with 8.5±1.8 mg/L higher DOC than in 10-30 cm depth with 5.6±0.5 mg/L, which may indicate a mobilization of organic components in the upper layers. After 4-years PM, Ctot values were slightly higher than after 2-years PM and after OM. Surprisingly, after 4-years PM, CECeff values were with 138 - 157 mmolc/kg almost 2-fold higher than after 2-years PM and OM which had with 74 - 102 mmolc/kg comparable CECeff values. Long-term PM resulted in changes of soil pH and slightly increased Ctot which probably enhanced the CECeff of the soil. However, further investigations of the effect of PM on stability of soil organic matter and microbial community structure are needed.

  16. Influence of tunnel and soil parameters on vibrations from underground railways

    NASA Astrophysics Data System (ADS)

    Gupta, S.; Stanus, Y.; Lombaert, G.; Degrande, G.

    2009-10-01

    A parametric study is performed to identify the key parameters which have an important influence on the generation and propagation of vibrations from underground railways. In this paper, the parameters related to the tunnel and the soil are considered and their influence on the free field response is studied. The coupled periodic finite element-boundary element model and the pipe-in-pipe model have been used for this study. Both models account for the dynamic interaction between the train, the track, the tunnel and the soil. A general analytical formulation is used to compute the response of three-dimensional invariant or periodic media that are excited by moving loads. The response to moving loads is written in terms of the axle loads and the transfer functions. The parametric study can be carried out by separately analyzing the variations in the axle loads and the transfer functions. The axle loads are mainly influenced by the parameters related to the vehicle and the track, while the transfer functions are influenced by the properties of the track, the tunnel and the soil. In the present paper, the parameters related to the tunnel and soil are investigated. It is observed that the material damping and the shear modulus of the soil have an important influence on the propagation of vibrations. The influence of structural changes to the tunnel as well as geometrical properties such as the size and shape of the tunnel is investigated. It is observed that a larger tunnel results in a smaller response above the tunnel as more energy is radiated downwards. Moreover, it is demonstrated that the tunnel geometry has a considerable influence on the response closer to the tunnel.

  17. Estimation of soil parameters over bare agriculture areas from C-band polarimetric SAR data using neural networks

    NASA Astrophysics Data System (ADS)

    Baghdadi, N.; Cresson, R.; El Hajj, M.; Ludwig, R.; La Jeunesse, I.

    2012-06-01

    The purpose of this study was to develop an approach to estimate soil surface parameters from C-band polarimetric SAR data in the case of bare agricultural soils. An inversion technique based on multi-layer perceptron (MLP) neural networks was introduced. The neural networks were trained and validated on a noisy simulated dataset generated from the Integral Equation Model (IEM) on a wide range of surface roughness and soil moisture, as it is encountered in agricultural contexts for bare soils. The performances of neural networks in retrieving soil moisture and surface roughness were tested for several inversion cases using or not using a-priori knowledge on soil parameters. The inversion approach was then validated using RADARSAT-2 images in polarimetric mode. The introduction of expert knowledge on the soil moisture (dry to wet soils or very wet soils) improves the soil moisture estimates, whereas the precision on the surface roughness estimation remains unchanged. Moreover, the use of polarimetric parameters α1 and anisotropy were used to improve the soil parameters estimates. These parameters provide to neural networks the probable ranges of soil moisture (lower or higher than 0.30 cm3 cm-3) and surface roughness (root mean square surface height lower or higher than 1.0 cm). Soil moisture can be retrieved correctly from C-band SAR data by using the neural networks technique. Soil moisture errors were estimated at about 0.098 cm3 cm-3 without a-priori information on soil parameters and 0.065 cm3 cm-3 (RMSE) applying a-priori information on the soil moisture. The retrieval of surface roughness is possible only for low and medium values (lower than 2 cm). Results show that the precision on the soil roughness estimates was about 0.7 cm. For surface roughness lower than 2 cm, the precision on the soil roughness is better with an RMSE about 0.5 cm. The use of polarimetric parameters improves only slightly the soil parameters estimates.

  18. Estimation of the soil strength parameters in Tertiary volcanic regolith (NE Turkey) using analytical hierarchy process

    NASA Astrophysics Data System (ADS)

    Ersoy, Hakan; Karsli, Melek Betül; Çellek, Seda; Kul, Bilgehan; Baykan, İdris; Parsons, Robert L.

    2013-12-01

    Costly and time consuming testing techniques and the difficulties in providing undisturbed samples for these tests have led researchers to estimate strength parameters of soils with simple index tests. However, the paper focuses on estimation of strength parameters of soils as a function of the index properties. Analytical hierarchy process and multiple regression analysis based methodology were performed on datasets obtained from soil tests on 41 samples in Tertiary volcanic regolith. While the hierarchy model focused on determining the most important index properties affecting on strength parameters, regression analysis established meaningful relationships between strength parameters and index properties. The negative polynomial correlations between the friction angle and plasticity properties, and the positive exponential relations between the cohesion and plasticity properties were determined. These relations are characterized by a regression coefficient of 0.80. However, Terzaghi bearing capacity formulas were used to test the model. It is important to see whether there is any statistically significant relation between the calculated and the observed bearing capacity values for model testing. Based on the model, the positive linear correlation characterized by the regression coefficient of 0.86 were determined between bearing capacity values obtained by direct and indirect methods.

  19. Analysis of effective Green-Ampt hydraulic parameters for vertically layered soils

    NASA Astrophysics Data System (ADS)

    Deng, Peng; Zhu, Jianting

    2016-07-01

    While Green-Ampt model has been widely used in infiltration calculations through unsaturated soils, upscaling this model for applications in heterogeneous formations remains difficult. In this study, how to upscale soil parameters in the Green-Ampt model for vertically layered soils is examined. The main idea of upscaled effective parameters is to capture infiltration behavior in layered soil formations using only one set of parameters derived from the parameters of individual layers, such that the layered system can be replaced by an equivalent homogeneous medium. The general p-order power mean was proposed to represent the upscaling schemes of the Green-Ampt model. The optimal p value was determined by a general requirement of same total infiltration time for the layered formation and the equivalent homogeneous medium. The p-order power mean for the Green-Ampt parameters can capture the infiltration rates in the layered formations well, illustrating that the proposed upscaling schemes are reasonable to represent the overall behaviors of the heterogeneous layered formations. The structure of layered formations can significantly influence the upscaling results. However, when the number of layers becomes large, the layered formations tend to show homogeneity and the layer structure becomes less important. The results demonstrated that the scheme based on the harmonic mean for the saturated hydraulic conductivity and the general p-order power mean for the wetting front suction head can well capture the overall infiltration behaviors in both the coarse-layer-on-top and fine-layer-on-top formations, and thus is recommended as a general upscaling scheme when using the upscaled Green-Ampt model in layered formations.

  20. Support Vector Machines for Petrophysical Modelling and Lithoclassification

    NASA Astrophysics Data System (ADS)

    Al-Anazi, Ammal Fannoush Khalifah

    2011-12-01

    Given increasing challenges of oil and gas production from partially depleted conventional or unconventional reservoirs, reservoir characterization is a key element of the reservoir development workflow. Reservoir characterization impacts well placement, injection and production strategies, and field management. Reservoir characterization projects point and line data to a large three-dimensional volume. The relationship between variables, e.g. porosity and permeability, is often established by regression yet the complexities between measured variables often lead to poor correlation coefficients between the regressed variables. Recent advances in machine learning methods have provided attractive alternatives for constructing interpretation models of rock properties in heterogeneous reservoirs. Here, Support Vector Machines (SVMs), a class of a learning machine that is formulated to output regression models and classifiers of competitive generalization capability, has been explored to determine its capabilities for determining the relationship, both in regression and in classification, between reservoir rock properties. This thesis documents research on the capability of SVMs to model petrophysical and elastic properties in heterogeneous sandstone and carbonate reservoirs. Specifically, the capabilities of SVM regression and classification has been examined and compared to neural network-based methods, namely multilayered neural networks, radial basis function neural networks, general regression neural networks, probabilistic neural networks, and linear discriminant analysis. The petrophysical properties that have been evaluated include porosity, permeability, Poisson's ratio and Young's modulus. Statistical error analysis reveals that the SVM method yields comparable or superior predictions of petrophysical and elastic rock properties and classification of the lithology compared to neural networks. The SVM method also shows uniform prediction capability under the

  1. Effects of Temperature on Solute Transport Parameters in Differently-Textured Soils at Saturated Condition

    NASA Astrophysics Data System (ADS)

    Hamamoto, S.; Arihara, M.; Kawamoto, K.; Nishimura, T.; Komatsu, T.; Moldrup, P.

    2014-12-01

    Subsurface warming driven by global warming, urban heat islands, and increasing use of shallow geothermal heating and cooling systems such as the ground source heat pump, potentially causes changes in subsurface mass transport. Therefore, understanding temperature dependency of the solute transport characteristics is essential to accurately assess environmental risks due to increased subsurface temperature. In this study, one-dimensional solute transport experiments were conducted in soil columns under temperature control to investigate effects of temperature on solute transport parameters, such as solute dispersion and diffusion coefficients, hydraulic conductivity, and retardation factor. Toyoura sand, Kaolin clay, and intact loamy soils were used in the experiments. Intact loamy soils were taken during a deep well boring at the Arakawa Lowland in Saitama Prefecture, Japan. In the transport experiments, the core sample with 5-cm diameter and 4-cm height was first isotropically consolidated, whereafter 0.01M KCl solution was injected to the sample from the bottom. The concentrations of K+ and Cl- in the effluents were analyzed by an ion chromatograph to obtain solute breakthrough curves. The solute transport parameters were calculated from the breakthrough curves. The experiments were conducted under different temperature conditions (15, 25, and 40 oC). The retardation factor for the intact loamy soils decreased with increasing temperature, while water permeability increased due to reduced viscosity of water at higher temperature. Opposite, the effect of temperature on solute dispersivity for the intact loamy soils was insignificant. The effects of soil texture on the temperature dependency of the solute transport characteristics will be further investigated from comparison of results from differently-textured samples.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    During military operations, a small fraction of propellant mass is not consumed during firing and is deposited onto the ground surface (Jenkins et al., 2006). Soluble propellant constituents can be released from particulate residues into the environment. Propellant constituents of interest for this study are nitroglycerine (NG), 2,4-dinitrotoluine (2,4-DNT), 2,6-dinitrotoluine (2,6-DNT), and nitroguanidine (NQ). The goal of this work is to determine fate and transport parameters for these constituents in three soils that represent a range of geographic locations and soil properties. This supports a companion study that looks at dissolution of NG, 2,4-DNT, 2,6-DNT, and NQ from fired and unfired solid propellant formulations and their transport in soils. The three soils selected for the study are Catlin silt loam (fine-silty, mixed, mesic, superactive Oxyaquic Argiudoll), Plymouth sandy loam (mesic, coated Typic Quartzipsamment), and Sassafras loam (fine loamy, siliceous, mesic Typic Hapudult). Two of these soils, Plymouth sandy loam and Sassafras loam, were collected on military installations. Linear adsorption coefficients and transformation rates of propellant constituents were determined in batch kinetic experiments. Soils were mixed with propellant constituent solutions (2 mg L-1) at 4:1 solution/soil mass ratio and equilibrated for 0, 1, 2, 6, 12, 24, 48, and 120 hr at which time samples were centrifuged and supernatant solutions were analyzed for target compounds by high performance liquid chromatography (HPLC) using U.S. EPA Method 8330b for NG, 2,4-DNT, and 2,6-DNT, and Walsh (1989) method for NQ. Adsorption and transformation of propellant constituents were determined from the decrease in solution concentration of these compounds. It was determined that all studied compounds were subjected to sorption by the solid phase and degradation. Catlin soil, with finer texture and high organic matter content, influenced solution concentration of NG, 2,4-DNT, 2,6-DNT

  3. Relations among soil radon, environmental parameters, volcanic and seismic events at Mt. Etna (Italy)

    NASA Astrophysics Data System (ADS)

    Giammanco, S.; Ferrera, E.; Cannata, A.; Montalto, P.; Neri, M.

    2013-12-01

    From November 2009 to April 2011 soil radon activity was continuously monitored using a Barasol probe located on the upper NE flank of Mt. Etna volcano (Italy), close both to the Piano Provenzana fault and to the NE-Rift. Seismic, volcanological and radon data were analysed together with data on environmental parameters, such as air and soil temperature, barometric pressure, snow and rain fall. In order to find possible correlations among the above parameters, and hence to reveal possible anomalous trends in the radon time-series, we used different statistical methods: i) multivariate linear regression; ii) cross-correlation; iii) coherence analysis through wavelet transform. Multivariate regression indicated a modest influence on soil radon from environmental parameters (R2 = 0.31). When using 100-day time windows, the R2 values showed wide variations in time, reaching their maxima (~0.63-0.66) during summer. Cross-correlation analysis over 100-day moving averages showed that, similar to multivariate linear regression analysis, the summer period was characterised by the best correlation between radon data and environmental parameters. Lastly, the wavelet coherence analysis allowed a multi-resolution coherence analysis of the time series acquired. This approach allowed to study the relations among different signals either in the time or in the frequency domain. It confirmed the results of the previous methods, but also allowed to recognize correlations between radon and environmental parameters at different observation scales (e.g., radon activity changed during strong precipitations, but also during anomalous variations of soil temperature uncorrelated with seasonal fluctuations). Using the above analysis, two periods were recognized when radon variations were significantly correlated with marked soil temperature changes and also with local seismic or volcanic activity. This allowed to produce two different physical models of soil gas transport that explain the

  4. Using a scoop to derive soil mechanical parameters on the surface of Mars

    NASA Astrophysics Data System (ADS)

    Kargl, Günter; Poganski, Joshua; Kömle, Norbert I.; Schweiger, Helmut; Macher, Wolfgang

    2016-04-01

    We will report on the possibility of using the scoop attached to the instrument deployment arm to perform soil mechanical experiments directly on the surface of Mars. The Phoenix mission flown 2009 had an instrument deployment arm which was also used to sample surface material indo instruments mounted on the lander deck. The flight spare of this arm will again be flown to Mars on board the InSight mission. Although, the primary purpose of the arm and the attached scoop was not soil mechanical investigations it was already demonstrated by the Phoenix mission that the arm can be used to perform auxiliary investigations of the surface materials. We will report on modelling efforts using a Discrete Element Software package to demonstrate that simple soil mechanical experiments can be used to derive essential material parameters like e.g. angle of repose and others. This is of particular interest since it would be possible to implement experiments using the hardware of the InSight mission. PIC Cross section cut through a trench dug out by the scoop and the pile of the deposed material which both can be used to derive soil mechanical parameters.

  5. Prediction of ecotoxicity of hydrocarbon-contaminated soils using physicochemical parameters

    SciTech Connect

    Wong, D.C.L.; Chai, E.Y.; Chu, K.K.; Dorn, P.B.

    1999-11-01

    The physicochemical properties of eight hydrocarbon-contaminated soils were used to predict toxicity to earthworms (Eisenia fetida) and plants. The toxicity of these preremediated soils was assessed using earthworm avoidance, survival, and reproduction and seed germination and root growth in four plant species. No-observed-effect and 25% inhibitory concentrations were determined from the earthworm and plant assays. Physical property measurements and metals analyses of the soils were conducted. Hydrocarbon contamination was characterized by total petroleum hydrocarbons, oil and grease, and GC boiling-point distribution. Univariate and multivariate statistical methods were used to examine relationships between physical and chemical properties and biological endpoints. Soil groupings based on physicochemical properties and toxicity from cluster and principal component analyses were generally similar. Correlation analysis identified a number of significant relationships between soil parameters and toxicity that were used in univariate model development. Total petroleum hydrocarbons by gas chromatography and polars were identified as predictors of earthworm avoidance and survival and seed germination, explaining 65 to 75% of the variation in the data. Asphaltenes also explained 83% of the variation in seed germination. Gravimetric total petroleum hydrocarbons explained 40% of the variation in earthworm reproduction, whereas 43% of the variation in plant root growth was explained by asphaltenes. Multivariate one-component partial least squares models, which identified predictors similar to those identified by the univariate models, were also developed for worm avoidance and survival and seed germination and had predictive powers of 42 and 29%, respectively.

  6. A novel method for estimating the track-soil parameters based on Kalman and improved strong tracking filters.

    PubMed

    Yao, Yu; Cheng, Kai; Zhou, Zhi-Jie; Zhang, Bang-Cheng; Dong, Chao; Zheng, Sen

    2015-11-01

    A tracked vehicle has been widely used in exploring unknown environments and military fields. In current methods for suiting soil conditions, soil parameters need to be given and the traction performance cannot always be satisfied on soft soil. To solve the problem, it is essential to estimate track-soil parameters in real-time. Therefore, a detailed mathematical model is proposed for the first time. Furthermore, a novel algorithm which is composed of Kalman filter (KF) and improved strong tracking filter (STF) is developed for online track-soil estimation and named as KF-ISTF. By this method, the KF is used to estimate slip parameters, and the ISTF is used to estimate motion states. Then the key soil parameters can be estimated by using a suitable soil model. The experimental results show that equipped with the estimation algorithm, the proposed model can be used to estimate the track-soil parameters, and make the traction performance satisfied with soil conditions. PMID:26476477

  7. Assessment of soil electromagnetic parameters and their variation with soil water, salts: a comparison among EMI and TDR measuring methods

    NASA Astrophysics Data System (ADS)

    Chaali, Nesrine; Coppola, Antonio; Comegna, Alessandro; Dragonetti, Giovanna

    2015-04-01

    Numerous studies have analyzed the possibility of the extension of Electromagnetic Induction EMI calibration coefficients determined at field scale, to predict the depth distribution of bulk electrical conductivity ECb within unmonitored sites and/or times, in order to appraise the effect of salts dynamics on soils and plants. However, in the literature, it has been determined that the extension of those EMI calibration coefficients can be awkward since the calibration parameters are highly site-specific because of changes in water content, temperature, root development, soil physical properties, etc... So they can only be used in sites having similar characteristics in terms of EMI. Furthermore there is a difference in the observation windows of EMI sensors and of sensors (Time Domain Reflectometry TDR, Electrical Resistance Tomography ERT, ect...) used for measuring the ECb to be then used for the calibration and validation of the EMI. By consequence the actual variability of the soil salinity will be hidden due to the fact that data coming from EMI and other sensors have different variability patterns and structure, and are then influenced by different noises. The main objectives of this work were: 1) develop a practical and cost-effective technique that uses TDR data as ground-truth data for calibrating and validating of the EMI larger scale sensor, 2) using a Fourier transform FT analysis by applying a specific noise filter to the original data, to find the correlations between the TDR and the EMI data. An experiment was designed by irrigating three transects of green beans, 30 m long each, with three irrigation salinity inputs (1dSm-1, 3dSm-1, 6dSm-1). The irrigation volumes were estimated by measuring soil water content at different depths by using a Diviner 2000. During the experiment, the EM in both the vertical (EMV) and horizontal (EMH) configurations were regularly measured by a Geonics EM38 device. TDR probes were inserted vertically at the soil

  8. Temperature and volumetric water content petrophysical relationships in municipal solid waste for the interpretation of bulk electrical resistivity data

    NASA Astrophysics Data System (ADS)

    Pilawski, Tamara; Dumont, Gaël; Nguyen, Frédéric

    2015-04-01

    Landfills pose major environmental issues including long-term methane emissions, and local pollution of soil and aquifers but can also be seen as potential energy resources and mining opportunities. Water content in landfills determine whether solid fractions can be separated and recycled, and controls the existence and efficiency of natural or enhanced biodegradation. Geophysical techniques, such as electrical and electromagnetic methods have proven successful in the detection and qualitative investigation of sanitary landfills. However, their interpretation in terms of quantitative water content estimates makes it more challenging due to the influence of parameters such as temperature, compaction, waste composition or pore fluid. To improve the confidence given to bulk electrical resistivity data and to their interpretation, we established temperature and volumetric water content petrophysical relationships that we tested on field and laboratory electrical resistivity measurements. We carried out two laboratory experiments on leachates and waste samples from a landfill located in Mont-Saint-Guibert, Belgium. We determined a first relationship between temperature and electrical resistivity with pure and diluted leachates by progressively increasing the temperature from 5°C to 65°C, and then cooling down to 5°C. The second relationship was obtained by measuring electrical resistivity on waste samples of different volumetric water contents. First, we used the correlations obtained from the experiments to compare electrical resistivity measurements performed in a landfill borehole and on reworked waste samples excavated at different depths. Electrical resistivities were measured every 20cm with an electromagnetic logging device (EM39) while a temperature profile was acquired with optic fibres. Waste samples were excavated every 2m in the same borehole. We filled experimental columns with these samples and measured electrical resistivities at laboratory temperature

  9. Assessing Tillage Effects on Soil Hydraulic Properties via Inverse Parameter Estimation using Tension Infiltrometry

    NASA Astrophysics Data System (ADS)

    Schwen, Andreas; Bodner, Gernot; Loiskandl, Willibald

    2010-05-01

    Hydraulic properties are key factors controlling water and solute movement in soils. While several recent studies have focused on the assessment of the spatial variability of hydraulic properties, the temporal dynamics are commonly not taken into account, primarily because its measurement is costly and time-consuming. However, there is extensive empirical evidence that these properties are subject to temporal changes, particularly in the near-saturated range where soil structure strongly influences water flow. One main source of temporal variability is soil tillage. It can improve macroporosity by loosening the soil and thereby changing the pore-size distribution. Since these modifications are quite unstable over time, the pore space partially collapses after tillage. This effect should be largest for conventional tillage (CT), where the soil is ploughed after harvest every year. Assessing the effect of different tillage treatments on the temporal variability of hydraulic properties requires adequate measurement techniques. Tension infiltrometry has become a popular and convenient method providing not only the hydraulic conductivity function but also the soil rentention properties. The inverse estimation of parameters from infiltration measurements remains challenging, despite some progress since the first approach of Šimůnek et al. (1998). Measured data like the cumulative infiltration, the initial and final volumetric water content, as well as independently measured retention data from soil core analysis with laboratory methods, have to be considered to find an optimum solution describing the soil's pore space. In the present study we analysed tension infiltration measurements obtained several times between August 2008 and December 2009 on an arable field in the Moravian Basin, Lower Austria. The tillage treatments were conventional tillage including ploughing (CT), reduced tillage with chisel only (RT), and no-tillage treatment using a direct seeding

  10. Mapping of bare soil surface parameters from TerraSAR-X radar images over a semi-arid region

    NASA Astrophysics Data System (ADS)

    Gorrab, A.; Zribi, M.; Baghdadi, N.; Lili Chabaane, Z.

    2015-10-01

    The goal of this paper is to analyze the sensitivity of X-band SAR (TerraSAR-X) signals as a function of different physical bare soil parameters (soil moisture, soil roughness), and to demonstrate that it is possible to estimate of both soil moisture and texture from the same experimental campaign, using a single radar signal configuration (one incidence angle, one polarization). Firstly, we analyzed statistically the relationships between X-band SAR (TerraSAR-X) backscattering signals function of soil moisture and different roughness parameters (the root mean square height Hrms, the Zs parameter and the Zg parameter) at HH polarization and for an incidence angle about 36°, over a semi-arid site in Tunisia (North Africa). Results have shown a high sensitivity of real radar data to the two soil parameters: roughness and moisture. A linear relationship is obtained between volumetric soil moisture and radar signal. A logarithmic correlation is observed between backscattering coefficient and all roughness parameters. The highest dynamic sensitivity is obtained with Zg parameter. Then, we proposed to retrieve of both soil moisture and texture using these multi-temporal X-band SAR images. Our approach is based on the change detection method and combines the seven radar images with different continuous thetaprobe measurements. To estimate soil moisture from X-band SAR data, we analyzed statistically the sensitivity between radar measurements and ground soil moisture derived from permanent thetaprobe stations. Our approaches are applied over bare soil class identified from an optical image SPOT / HRV acquired in the same period of measurements. Results have shown linear relationship for the radar signals as a function of volumetric soil moisture with high sensitivity about 0.21 dB/vol%. For estimation of change in soil moisture, we considered two options: (1) roughness variations during the three-month radar acquisition campaigns were not accounted for; (2) a simple

  11. Existing approaches to tight rock laboratory petrophysics: a critical review

    NASA Astrophysics Data System (ADS)

    Konoshonkin, D. V.; Parnachev, S. V.

    2015-02-01

    A review of the existing methods for tight rock porosity, saturation, and permeability determination was performed taking into account that these methods should be applicable for Bazhenov formation evaluation. The following methods were considered: Archimedes mercury immersion; mercury displacement; caliper; helium pycnometry on crushed samples; nuclear magnetic resonance; modified retort method; modified Dean-Stark extraction; pulse decay method; and pressure decay test on crushed samples. The applicability of the pressure decay test on a crushed sample for Bazhenov formation evaluation is checked experimentally with the SMP-200 commercial permeameter. All the above listed methods were combined into five protocols for tight rock petrophysical evaluation. These protocols were analyzed and compared according to the following criteria: accuracy of the results; usage experience; time of measurements; easiness of interpretation; reliability and safety; price. The obtained results revealed that the most effective protocol is the one that includes pressure pulse on a core plug for permeability determination, He pycnometry and modified retort analysis on crushed samples for porosity and saturation determination. As there were cases when the proposed protocol was less effective vs. other protocols, a special scheme was suggested in order to choose the most effective protocol for tight rock petrophysical properties evaluation in definite conditions.

  12. Coupled simulation of surface runoff and soil water flow using multi-objective parameter estimation

    NASA Astrophysics Data System (ADS)

    Köhne, John Maximilian; Wöhling, Thomas; Pot, Valérie; Benoit, Pierre; Leguédois, Sophie; Le Bissonnais, Yves; Šimůnek, Jirka

    2011-06-01

    SummaryA comprehensive description of water flow in environmental and agricultural systems requires an account of both surface and subsurface pathways. We present a new model which combines a 1D overland flow model and the 2D subsurface flow HYDRUS-2D model, and uses the multi-objective global search method AMALGAM for inverse parameter estimation. Furthermore, we present data from bench-scale flow experiments which were conducted with two 5-m long replicate soil channels. While rainfall was applied, surface runoff was recorded at the downstream end of the soil channel, subsurface drainage waters were sampled at three positions equally spaced along the channels, and pressure heads were recorded at five depths. The experimental observations were used to evaluate the performance of our modeling system. The complexity of the modeling approach was increased in three steps. First, only runoff and total drainage were simulated, then drainage flows from individual compartments were additionally evaluated, and finally a surface crust and immobile soil water were also considered. The results showed that a good match between measured and observed surface runoff and total drainage does not guarantee accurate representation of the flow process. An inspection of the Pareto results of different multiobjective calibration runs revealed a significant trade-off between individual objectives, showing that no single solution existed to match spatial variability in the flow. In spite of the observed crust formation, its consideration in the more complex model structure did not significantly improve the fit between the model and measurements. Accounting for immobile water regions only slightly improved the fit for one of the two replicate soil channels. Discrepancies between relatively complex model simulations and seemingly simple soil channel experiments suggest the presence of additional unknowns, such as heterogeneity of the soil hydraulic properties. Nevertheless, with its

  13. Magnetic Parameter Changes in Soil and Sediments in the Presence of Hydrocarbon Contamination

    NASA Astrophysics Data System (ADS)

    Appel, E.; Porsch, K.; Rijal, M. L.; Ameen, N. N.; Kappler, A.

    2014-12-01

    Magnetic proxies were successfully used for fast and non-destructive detection of fly ash related heavy metal pollution. Correlations of magnetic signals with organic contaminants in soils and sediments were also reported; however, their significance is unclear because of co-existing heavy metal pollution. At a hydrocarbon (HC) contaminated former military airbase (Hradcany, Czech Rep.), where heavy metal contents are insignificant, we detected clearly higher magnetic concentrations at the top of the groundwater fluctuation (GWF) zone. Frequent GWF by up to ca. one meter was caused through remediation by air sparging. In this study and all previous ones magnetite was identified as the dominant phase for higher magnetic concentrations. To determine the importance of microbial activity and soil parameters on changes in magnetic susceptibility (MS) laboratory batch experiments with different microbially active and sterile soils without carbon addition and with gasoline amendment were setup. MS of these microcosms was followed weekly. Depending on the soil MS either increased or decreased by up to ~7% and remained constant afterwards. The main findings were that MS changes were mainly microbially driven and influenced by the bioavailable Fe content, the initial MS and the organic carbon content of the soils. Moreover, we tested magnetic changes in laboratory columns, filled with sand from the field site Hradcany, by simulating water level changes. The observed changes were small and hardly statistically significant. Our laboratory studies revealed that different factors influence changes in magnetic properties of soil/sediments after HC contamination, with much smaller effects than expected from anomalies observed at field sites. With the present results, the ambitious goal of using magnetic monitoring for detecting HC contaminations by oil spills seem far from practical application.

  14. Soil biochar amendment as a climate change mitigation tool: Key parameters and mechanisms involved.

    PubMed

    Brassard, Patrick; Godbout, Stéphane; Raghavan, Vijaya

    2016-10-01

    Biochar, a solid porous material obtained from the carbonization of biomass under low or no oxygen conditions, has been proposed as a climate change mitigation tool because it is expected to sequester carbon (C) for centuries and to reduce greenhouse gas (GHG) emissions from soils. This review aimed to identify key biochar properties and production parameters that have an effect on these specific applications of the biochar. Moreover, mechanisms involved in interactions between biochar and soils were highlighted. Following a compilation and comparison of the characteristics of 76 biochars from 40 research studies, biochars with a lower N content, and consequently a higher C/N ratio (>30), were found to be more suitable for mitigation of N2O emissions from soils. Moreover, biochars produced at a higher pyrolysis temperature, and with O/C ratio <0.2, H/Corg ratio <0.4 and volatile matter below 80% may have high C sequestration potential. Based on these observations, biochar production and application to the field can be used as a tool to mitigate climate change. However, it is important to determine the pyrolysis conditions and feedstock needed to produce a biochar with the desired properties for a specific application. More research studies are needed to identify the exact mechanisms involved following biochar amendment to soil. PMID:27420171

  15. Simulating solute transport in a structured field soil: uncertainty in parameter identification and predictions.

    PubMed

    Larsbo, Mats; Jarvis, Nicholas

    2005-01-01

    Dual-permeability models have been developed to account for the significant effects of macropore flow on contaminant transport, but their use is hampered by difficulties in estimating the additional parameters required. Therefore, our objective was to evaluate data requirements for parameter identification for predictive modeling with the dual-permeability model MACRO. Two different approaches were compared: sequential uncertainty fitting (SUFI) and generalized likelihood uncertainty estimation (GLUE). We investigated six parameters controlling macropore flow and pesticide sorption and degradation, applying MACRO to a comprehensive field data set of bromide andbentazone [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one-2,2dioxide] transport in a structured soil. The GLUE analyses of parameter conditioning for different combinations of observations showed that both resident and flux concentrations were needed to obtain highly conditioned and unbiased parameters and that observations of tracer transport generally improved the conditioning of macropore flow parameters. The GLUE "behavioral" parameter sets covered wider parameter ranges than the SUFI posterior uncertainty domains. Nevertheless, estimation uncertainty ranges defined by the 5th and 95th percentiles were similar and many simulations randomly sampled from the SUFI posterior uncertainty domains had negative model efficiencies (minimum of -3.2). This is because parameter correlations are neglected in SUFI and the posterior uncertainty domains were not always determined correctly. For the same reasons, uncertainty ranges for predictions of bentazone losses through drainflow for good agricultural practice in southern Sweden were 27% larger for SUFI compared with GLUE. Although SUFI proved to be an efficient parameter estimation tool, GLUE seems better suited as a method of uncertainty estimation for predictions. PMID:15758115

  16. Hydrothermal carbonization of biomass from landscape management - Influence of process parameters on soil properties of hydrochars.

    PubMed

    Röhrdanz, Michael; Rebling, Tammo; Ohlert, Jan; Jasper, Jan; Greve, Thomas; Buchwald, Rainer; von Frieling, Petra; Wark, Michael

    2016-05-15

    Besides pyrolysis the technology of hydrothermal carbonization (HTC) is tested to produce hydrochars for soil improvement. The chemical and physical properties of the hydrochars mainly depend on the feedstock and the process parameters reaction time and process temperature. Systematic investigations on the influences of these process parameters on soil properties of hydrochars like water holding capacity (WHC) and cation exchange capacity (CEC) are missing. In this study, a rush-rich biomass was carbonized within defined HTC process conditions under variation of reaction time and process temperature to produce hydrochars. Analysis of WHC, CEC, the elemental composition and Fourier-transform infrared spectroscopy (FT-IR) were performed to evaluate the influence of HTC process conditions on the pedological hydrochar properties. The results indicated that at increasing reaction severity (reaction time and process temperature) WHC and CEC decreased as well as the elemental O/C ratio. The decrease of WHC and CEC is based on the decrease of the hydrochar surface polarity. However, even the lowest WHC and CEC of investigated hydrochars still exceeded those of pure quartz sand by factors of 5-10. An application of hydrochars produced at severe HTC conditions could improve WHC and CEC of sandy soils. This has to be investigated in further studies. PMID:26974240

  17. Effects of Seismological and Soil Parameters on Earthquake Energy demand in Level Ground Sand Deposits

    NASA Astrophysics Data System (ADS)

    nabili, sara; shahbazi majd, nafiseh

    2013-04-01

    Liquefaction has been a source of major damages during severe earthquakes. To evaluate this phenomenon there are several stress, strain and energy based approaches. Use of the energy method has been more focused by researchers due to its advantages with respect to other approaches. The use of the energy concept to define the liquefaction potential is validated through laboratory element and centrifuge tests as well as field studies. This approach is based on the hypothesis that pore pressure buildup is directly related to the dissipated energy in sands which is the accumulated areas between the stress-strain loops. Numerous investigations were performed to find a relationship which correlates the dissipated energy to the soil parameters, but there are not sufficient studies to relate this dissipated energy, known as demand energy, concurrently, to the seismological and the soil parameters. The aim of this paper is to investigate the dependency of the demand energy in sands to seismological and the soil parameters. To perform this task, an effective stress analysis has been executed using FLAC finite difference program. Finn model, which is a built-in constitutive model implemented in FLAC program, was utilized. Since an important stage to predict the liquefaction is the prediction of excess pore water pressure at a given point, a simple numerical framework is presented to assess its generation during a cyclic loading in a given centrifuge test. According to the results, predicted excess pore water pressures did not closely match to the measured excess pore water pressure values in the centrifuge test but they can be used in the numerical assessment of excess pore water pressure with an acceptable degree of preciseness. Subsequently, the centrifuge model was reanalyzed using several real earthquake acceleration records with different seismological parameters such as earthquake magnitude and Hypocentral distance. The accumulated energies (demand energy) dissipated in

  18. Lignin decomposition along an Alpine elevation gradient in relation to physicochemical and soil microbial parameters.

    PubMed

    Duboc, Olivier; Dignac, Marie-France; Djukic, Ika; Zehetner, Franz; Gerzabek, Martin H; Rumpel, Cornelia

    2014-07-01

    Lignin is an aromatic plant compound that decomposes more slowly than other organic matter compounds; however, it was recently shown that lignin could decompose as fast as litter bulk carbon in minerals soils. In alpine Histosols, where organic matter dynamics is largely unaffected by mineral constituents, lignin may be an important part of soil organic matter (SOM). These soils are expected to experience alterations in temperature and/or physicochemical parameters as a result of global climate change. The effect of these changes on lignin dynamics remains to be examined and the importance of lignin as SOM compound in these soils evaluated. Here, we investigated the decomposition of individual lignin phenols of maize litter incubated for 2 years in-situ in Histosols on an Alpine elevation gradient (900, 1300, and 1900 m above sea level); to this end, we used the cupric oxide oxidation method and determined the phenols' (13) C signature. Maize lignin decomposed faster than bulk maize carbon in the first year (86 vs. 78% decomposed); however, after the second year, lignin and bulk C decomposition did not differ significantly. Lignin mass loss did not correlate with soil temperature after the first year, and even correlated negatively at the end of the second year. Lignin mass loss also correlated negatively with the remaining maize N at the end of the second year, and we interpreted this result as a possible negative influence of nitrogen on lignin degradation, although other factors (notably the depletion of easily degradable carbon sources) may also have played a role at this stage of decomposition. Microbial community composition did not correlate with lignin mass loss, but it did so with the lignin degradation indicators (Ac/Al)s and S/V after 2 years of decomposition. Progressing substrate decomposition toward the final stages thus appears to be linked with microbial community differentiation. PMID:24323640

  19. A soil parameters geodatabase for the modeling assessment of agricultural conservation practices effects in the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil parameters for hydrology modeling in cropland dominated areas, from the regional to local scale, are part of critical biophysical information whose deficiency may increase the uncertainty of simulated conservation effects and predicting potential. Despite this importance, soil physical and hyd...

  20. Predicting Cereal Root Disease in Western Australia Using Soil DNA and Environmental Parameters.

    PubMed

    Poole, Grant J; Harries, Martin; Hüberli, D; Miyan, S; MacLeod, W J; Lawes, Roger; McKay, A

    2015-08-01

    Root diseases have long been prevalent in Australian grain-growing regions, and most management decisions to reduce the risk of yield loss need to be implemented before the crop is sown. The levels of pathogens that cause the major root diseases can be measured using DNA-based services such as PreDicta B. Although these pathogens are often studied individually, in the field they often occur as mixed populations and their combined effect on crop production is likely to vary across diverse cropping environments. A 3-year survey was conducted covering most cropping regions in Western Australia, utilizing PreDicta B to determine soilborne pathogen levels and visual assessments to score root health and incidence of individual crop root diseases caused by the major root pathogens, including Rhizoctonia solani (anastomosis group [AG]-8), Gaeumannomyces graminis var. tritici (take-all), Fusarium pseudograminearum, and Pratylenchus spp. (root-lesion nematodes) on wheat roots for 115, 50, and 94 fields during 2010, 2011, and 2012, respectively. A predictive model was developed for root health utilizing autumn and summer rainfall and soil temperature parameters. The model showed that pathogen DNA explained 16, 5, and 2% of the variation in root health whereas environmental parameters explained 22, 11, and 1% of the variation in 2010, 2011, and 2012, respectively. Results showed that R. solani AG-8 soil pathogen DNA, environmental soil temperature, and rainfall parameters explained most of the variation in the root health. This research shows that interactions between environment and pathogen levels before seeding can be utilized in predictive models to improve assessment of risk from root diseases to assist growers to plan more profitable cropping programs. PMID:25822184

  1. Modelling the impact of atmospheric parameters on nitrous oxide emissions from soil

    NASA Astrophysics Data System (ADS)

    Thieme, Christoph; Biernath, Christian; Klein, Christian; Heinlein, Florian; Priesack, Eckart

    2015-04-01

    The trace gas N2O is a very stable and thus potent greenhouse gas and is the main contributor for the recent depletion of ozone in the atmosphere. In order reduce N2O emissions, underlying processes have been investigated intensively. Important drivers for the formation of N2O in soils are known since decades, but how the atmospheric conditions affect N2O-fluxes is widely unknown. The aim of this study is to observe and discuss interactions between N2O-fluxes and relevant atmospheric parameters, i.e. the friction velocity, Obhukov-Length and canopy height. To analyze this we implemented an Eddy Covariance Station in combination with a Quantum-Cascade-Dual-Laser produced by Aerodyne Research Inc. (Billerca, Mass., USA) at an intensively managed agricultural field site at the TERENO research farm Scheyern (Germany), which is part of the TERENO preAlps-observatory. The measurement device allows in-situ flux measurements without disturbance of the atmosphere. Continuous flux-measurements started on 2014-11-01. Preliminary measurement results support the importance to consider atmospheric parameters to explain the strength of N2O-fluxes. The measurements indicate a positive relationship between N2O-fluxes and friction velocity in agreement with a models proposed by Garland (1977) or Owen and Thompson (1966). Based on these measurements we propose a new model following Garland (1977) to simulate N2O fluxes on the field scale. The new model will be implemented in the modular ecosystem software framework Expert-N 5.0, which is already able to simulate the formation and transport within the soil. However, until now, a simple empiric gradient between the atmospheric and soil N2O concentrations was used to compute the N2O fluxes in terrestrial ecosystems. The new resistance model accounts for the effects of atmospheric parameters (such as the friction velocity) on that gradient and is thus more physical.

  2. Sensitivity of water stress in a two-layered sandy grassland soil to variations in groundwater depth and soil hydraulic parameters

    NASA Astrophysics Data System (ADS)

    Rezaei, M.; Seuntjens, P.; Joris, I.; Boënne, W.; Van Hoey, S.; Campling, P.; Cornelis, W. M.

    2015-07-01

    Monitoring and modeling tools may improve irrigation strategies in precision agriculture. We used non-invasive soil moisture monitoring, a crop growth and a soil hydrological model to predict soil-water content fluctuations and crop yield in a heterogeneous sandy grassland soil under supplementary irrigation. The sensitivity of the model to hydraulic parameters, water stress, crop yield and lower boundary conditions was assessed. Free drainage and incremental constant head conditions was implemented in a lower boundary sensitivity analysis. A time-dependent sensitivity analysis showed that changes in soil water content are mainly affected by the soil saturated hydraulic conductivity Ks and the Mualem-van Genuchten retention curve shape parameters n and α. Results further showed that different parameter optimization strategies (two-, three-, four- or six-parameter optimizations) did not affect the calculated water stress and water content as significantly as does the bottom boundary. For this case, a two-parameter scenario, where Ks was optimized for each layer under the condition of a constant groundwater depth at 135-140 cm, performed best. A larger yield reduction, and a larger number and longer duration of stress conditions occurred in the free drainage condition as compared to constant boundary conditions. Numerical results showed that optimal irrigation scheduling using the aforementioned water stress calculations can save up to 12-22 % irrigation water as compared to the current irrigation regime. This resulted in a yield increase of 4.5-6.5 %, simulated by crop growth model.

  3. Petrophysical evaluation of the hydrocarbon potential of the Lower Cretaceous Kharita clastics, North Qarun oil field, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Teama, Mostafa A.; Nabawy, Bassem S.

    2016-09-01

    Based on the available well log data of six wells chosen in the North Qarun oil field in the Western Desert of Egypt, the petrophysical evaluation for the Lower Cretaceous Kharita Formation was accomplished. The lithology of Kharita Formation was analyzed using the neutron porosity-density and the neutron porosity-gamma ray crossplots as well as the litho-saturation plot. The petrophysical parameters, include shale volume, effective porosity, water saturation and hydrocarbon pore volume, were determined and traced laterally in the studied field through the iso-parametric maps. The lithology crossplots of the studied wells show that the sandstone is the main lithology of the Kharita Formation intercalated with some calcareous shale. The cutoff values of shale volume, porosity and water saturation for the productive hydrocarbon pay zones are defined to be 40%, 10% and 50%, respectively, which were determined, based on the applied crossplots approach and their limits. The iso-parametric contour maps for the average reservoir parameters; such as net-pay thickness, average porosity, shale volume, water saturation and the hydrocarbon pore volume were illustrated. From the present study, it is found that the Kharita Formation in the North Qarun oil field has promising reservoir characteristics, particularly in the northwestern part of the study area, which is considered as a prospective area for oil accumulation.

  4. Urban Heat Island Modeling in Conjunction with Satellite-Derived Surface/Soil Parameters.

    NASA Astrophysics Data System (ADS)

    Hafner, Jan; Kidder, Stanley Q.

    1999-04-01

    Although it has been studied for over 160 years, the urban heat island (UHI) effect is still not completely understood, yet it is increasingly important. The main purpose of this work is to improve UHI modeling by using AVHRR (Advanced Very High Resolution Radiometer) satellite data to retrieve the surface parameters (albedo, as well as soil thermal and moisture properties). In this study, a hydrostatic three-dimensional mesoscale model was used to perform the numerical modeling. The Carlson technique was applied to retrieve the thermal inertia and moisture availability using the thermal AVHRR channels 4 and 5. The net urban effect was determined as the difference between urban and nonurban simulations, in which urban parameters were replaced by rural parameters.Two winter days were each used for two numerical simulations: a control and an urban-to-rural replacement run. Moisture availability values on the less windy day showed generally a south to north gradient downwind of the city and urban values less than rural values (the urban dry island day). Moisture availability was higher on the windy day, with uniform values in the rural and urban areas (uniform soil moisture day). The only exceptions were variations in the rural hills north of the city and the low rural values under the polluted urban plume downwind of the city.While thermal inertia values showed no urban-rural differences on the uniform soil moisture day, they exhibited larger values over Atlanta than in surrounding rural area on the (less moist) dry island day. Two puzzling facts exist in the data: 1) lack of a north-south thermal inertia gradient on the dry soil day to correspond to its above-mentioned moisture availability gradient and 2) rural thermal inertia values do not change between both days in spite of their large difference in soil moisture. The observed lack of corresponding urban change is expected, as its thermal inertia values depend more on urban building materials than on moisture of

  5. 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.

  6. Geology and Petrophysics of the Ozouri Group, Central Gabon

    SciTech Connect

    Dunne, L.A.; Johnson, P.R.; DeSantis, S.B.

    1996-08-01

    The Ozouri Group in Gabon is comprised of finely textured siliceous dolomitic and calcareous claystones, shales, limestones, dolomites, porcellanite and cherts. It was deposited during the Late Paleocene and Early Eocene on a transgressive continental margin. It is highly siliceous and organically rich, with affinities to the Miocene Monterey Formation of California. It is often fractured by deeper structural movement of the underlying Ezanga salt. Economic oil production from the Ozouri is dependent on the most effective combination of matrix (storage) and fracture (deliverability) porosity. The most efficient combination can be related to variations in the lithologic and petrophysical characteristics of the formation. Horizontal drilling techniques can be utilized to fully exploit production from the Ozouri Group.

  7. Adequacy of transport parameters obtained in soil column experiments for selected chemicals

    NASA Astrophysics Data System (ADS)

    Raymundo-Raymundo, E.; Nikolskii, Yu. N.; Guber, A. K.; Landeros-Sanchez, C.

    2012-07-01

    The transport parameters were determined for the 18O isotope (in the form of H2 18O), the Br- ion, and atrazine in intact columns of allophanic Andosol (Mexico State, Mexico). A one-dimensional model for the convective-dispersive transport of chemicals with account for the decomposition and equilibrium adsorption (HYDRUS-1D), which is widely applied for assessing the risk of the chemical and bacterial contamination of natural waters, was used. The model parameters were obtained by solving the inverse problem on the basis of laboratory experiments on the transport of the 18O isotope, the Br- ion, and atrazine in intact soil columns at a fixed filtration velocity. The hydrodynamic dispersion parameters determined for the 18O and Br- ions in one column were of the same order of magnitude, and those for atrazine were higher by 3-4 times. The obtained parameters were used to calculate the transport of these substances in another column with different values of the water content and filtration velocity. The transport process was adequately described only for the 18O isotope. In the case of the Br- ion, the model significantly underestimated the transport velocity; for atrazine, its peak concentration in the column was overestimated. The column study of the transport of the three chemical compounds showed that transport parameters could not be reliably predicted from the results of a single experiment, even when several compounds were used in this experiment.

  8. How do alternative root water uptake models affect the inverse estimation of soil hydraulic parameters and the prediction of evapotranspiration?

    NASA Astrophysics Data System (ADS)

    Gayler, Sebastian; Salima-Sultana, Daisy; Selle, Benny; Ingwersen, Joachim; Wizemann, Hans-Dieter; Högy, Petra; Streck, Thilo

    2016-04-01

    Soil water extraction by roots affects the dynamics and distribution of soil moisture and controls transpiration, which influences soil-vegetation-atmosphere feedback processes. Consequently, root water uptake requires close attention when predicting water fluxes across the land surface, e.g., in agricultural crop models or in land surface schemes of weather and climate models. The key parameters for a successful simultaneous simulation of soil moisture dynamics and evapotranspiration in Richards equation-based models are the soil hydraulic parameters, which describe the shapes of the soil water retention curve and the soil hydraulic conductivity curve. As measurements of these parameters are expensive and their estimation from basic soil data via pedotransfer functions is rather inaccurate, the values of the soil hydraulic parameters are frequently inversely estimated by fitting the model to measured time series of soil water content and evapotranspiration. It is common to simulate root water uptake and transpiration by simple stress functions, which describe from which soil layer water is absorbed by roots and predict when total crop transpiration is decreased in case of soil water limitations. As for most of the biogeophysical processes simulated in crop and land surface models, there exist several alternative functional relationships for simulating root water uptake and there is no clear reason for preferring one process representation over another. The error associated with alternative representations of root water uptake, however, contributes to structural model uncertainty and the choice of the root water uptake model may have a significant impact on the values of the soil hydraulic parameters estimated inversely. In this study, we use the agroecosystem model system Expert-N to simulate soil moisture dynamics and evapotranspiration at three agricultural field sites located in two contrasting regions in Southwest Germany (Kraichgau, Swabian Alb). The Richards

  9. New petrophysical magnetic methods MACC and MAFM in permeability characterisation of petroleum reservoir rock cleaning, flooding modelling and determination of fines migration in formation damage

    NASA Astrophysics Data System (ADS)

    Ivakhnenko, O. P.

    2012-04-01

    Potential applications of magnetic techniques and methods in petroleum engineering and petrophysics (Ivakhnenko, 1999, 2006; Ivakhnenko & Potter, 2004) reveal their vast advantages for the petroleum reservoir characterisation and formation evaluation. In this work author proposes for the first time developed systematic methods of the Magnetic Analysis of Core Cleaning (MACC) and Magnetic Analysis of Fines Migration (MAFM) for characterisation of reservoir core cleaning and modelling estimations of fines migration for the petroleum reservoir formations. Using example of the one oil field we demonstrate results in application of these methods on the reservoir samples. Petroleum reservoir cores samples have been collected within reservoir using routine technique of reservoir sampling and preservation for PVT analysis. Immediately before the MACC and MAFM studies samples have been exposed to atmospheric air for a few days. The selected samples have been in detailed way characterised after fluid cleaning and core flooding by their mineralogical compositions and petrophysical parameters. Mineralogical composition has been estimated utilizing XRD techniques. The petrophysical parameters, such as permeability and porosity have been measured on the basis of total core analysis. The results demonstrate effectiveness and importance of the MACC and MAFM methods for the routine core analysis (RCAL) and the special core analysis (SCAL) in the reservoir characterisation, core flooding and formation damage analysis.

  10. Reflectance of vegetation, soil, and water. [effects of measurable plant parameters on multispectral signal variations

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L. (Principal Investigator)

    1974-01-01

    The author has identified the following significant results. Reflectance of crop residues, that are important in reducing wind and water erosion, was more often different from bare soil in band 4 than in bands 5, 6, or 7. The plant parameters leaf area index, plant population, plant cover, and plant height explained 95.9 percent of the variation in band 7 (reflective infrared) digital counts for cotton and 78.2 percent of the variation in digital counts for the combined crops sorghum and corn; hence, measurable plant parameters explain most of the signal variation recorded for corpland. Leaf area index and plant population are both highly correlated with crop yields; since plant population can be readily measured (or possibly inferred from seeding rates), it is useful measurement for calibrating ERTS-type MSS digital data in terms of yield.

  11. Parameter Measurement and Estimation at Variable Scales: Example of Soil Temperature in Complex Terrain

    NASA Astrophysics Data System (ADS)

    Seyfried, M. S.

    2015-12-01

    The issue of matching measurement scale to application scale is long standing and frequently revisited with advances in instrumentation and computing power. In the past we have emphasized the importance of understanding the dominant processes and amount and nature of parameter variability when addressing these issues. Landscape-scale distribution of carbon and carbon fluxes is a primary focus of the Reynolds Creek Critical Zone Observatory (RC CZO). Soil temperature (Ts) is a critical parameter of generally unknown variability. Estimates of Ts are often based on air temperature (Ta), but it is understood that other factors control Ts, especially in complex terrain, where solar radiation may be a major driver. Data were collected at the Reynolds Creek Experimental Watershed (RCEW), which is 240 km2 in extent and covers a 1000 m elevation range. We used spatially extensive Ts data to evaluate correlations with Ta (915 m elevation gradient) on aspect neutral sites with similar vegetative cover. Effects of complex terrain were evaluated using a combination of fixed point measurements, fiber optic distributed temperature sensing and periodic, spatially distributed point measurements. We found that Ts over the elevation gradient followed Ta closely. However, within small subwatersheds with uniform Ta, Ts may be extremely variable, with a standard deviation of 8° C. This was strongly related to topographically associated land surface units (LSU's) and highly seasonal. Within LSU variability was generally low while there were seasonally significant differences between LSU's. The mean annual soil temperature difference between LSU's was greater than that associated with the 915 m elevation gradient. The seasonality of Ts variability was not directly related to solar radiation effects but rather to variations in cover. Scaling Ts requires high resolution accounting of topography in this environment. Spatial patterns of soil carbon at the RCEW are consistent with this.

  12. Sensitivity of water stress in a two-layered sandy grassland soil to variations in groundwater depth and soil hydraulic parameters

    NASA Astrophysics Data System (ADS)

    Rezaei, M.; Seuntjens, P.; Joris, I.; Boënne, W.; Van Hoey, S.; Campling, P.; Cornelis, W. M.

    2016-01-01

    Monitoring and modelling tools may improve irrigation strategies in precision agriculture. We used non-invasive soil moisture monitoring, a crop growth and a soil hydrological model to predict soil water content fluctuations and crop yield in a heterogeneous sandy grassland soil under supplementary irrigation. The sensitivity of the soil hydrological model to hydraulic parameters, water stress, crop yield and lower boundary conditions was assessed after integrating models. Free drainage and incremental constant head conditions were implemented in a lower boundary sensitivity analysis. A time-dependent sensitivity analysis of the hydraulic parameters showed that changes in soil water content are mainly affected by the soil saturated hydraulic conductivity Ks and the Mualem-van Genuchten retention curve shape parameters n and α. Results further showed that different parameter optimization strategies (two-, three-, four- or six-parameter optimizations) did not affect the calculated water stress and water content as significantly as does the bottom boundary. In this case, a two-parameter scenario, where Ks was optimized for each layer under the condition of a constant groundwater depth at 135-140 cm, performed best. A larger yield reduction, and a larger number and longer duration of stress conditions occurred in the free drainage condition as compared to constant boundary conditions. Numerical results showed that optimal irrigation scheduling using the aforementioned water stress calculations can save up to 12-22 % irrigation water as compared to the current irrigation regime. This resulted in a yield increase of 4.5-6.5 %, simulated by the crop growth model.

  13. Soil microbial parameters and stability of soil aggregate fractions under different grassland communities on the Loess Plateau, China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over-grazing and large scale monocultures on the Loess plateau in China have caused serious soil erosion by water and wind. Grassland revegetation has been reported as one of the most effective counter measures. Therefore, we investigated soil aggregation, aggregate stability and soil microbial ac...

  14. Characterizing Soil Hydraulic Parameter Heterogeneity Using Cokriging and Artificial Neural Network: A Framework of Integrating Hard and Soft Data

    NASA Astrophysics Data System (ADS)

    Ye, M.; Schaap, M. G.; Khaleel, R.; Zhu, J.

    2005-12-01

    Characterization of the heterogeneity of hydraulic parameters that control transport processes in the vadose zone is always difficult due to prohibitive investments involved with direct parameter measurements (so-called `hard' data). `Soft' data such as moisture content (θ) and results derived from geophysical measurements, however, carry significant information about media heterogeneity and should be included in site characterization, where possible. We developed a method to incorporate both `hard' and `soft' data using cokriging and artificial neural network (ANN) analyses to generate 3D spatially correlated structures of hydraulic parameters. This method was applied to a field injection experiment carried out in 2000 at the `Sisson and Lu' injection site at the U.S. Department of Energy's Hanford Site, WA. Available data included limited measurements of soil hydraulic parameters (i.e., saturated hydraulic conductivity and van Genuchten parameters, totaling 70 datasets) and soil characterization data (bulk density and percentages of gravel, coarse and fine sand, silt, and clay). A 3D initial θ field reflecting the geologic layering was available at 32 observation wells (1344 locations). We used variograms and cross-variograms to investigate the spatial correlation and cross-correlation of the initial θ measurements and soil characterization data variables. We used ANN-based pedotransfer functions to map soil characterization data to hydraulic parameters. Using initial θ as a secondary variable, we used a cokriging scheme to estimate 3D heterogeneous fields of the primary variables, the soil characterization data and, subsequently, 3D fields of the hydraulic parameters with the pedotransfer functions. These hydraulic parameter fields were then used to simulate the field injection experiment. The spatial moments of the measured and simulated θ were compared to evaluate the robustness of the developed method. The θ profiles at observation wells were

  15. Improving Space-borne Radiometer Soil Moisture Retrievals with Alternative Aggregation Rules for Ancillary Parameters in Highly Heterogeneous Vegetated Areas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Retrieving soil moisture from space-borne microwave radiometer observations often requires ancillary parameters such as surface vegetation opacity or vegetation water content. The conventional approach for deriving representative footprint-scale values of these parameters is to simply average the co...

  16. Effects of the resolution of soil dataset and precipitation dataset on SWAT2005 streamflow calibration parameters and simulation accuracy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The resultant calibration parameter values and simulation accuracy of hydrologic models such as the Soil and Water Assessment Tool (SWAT2005) depends on how well spatial input parameters describe the characteristics of the study area. The objectives of this study were to: 1) investigate the effect o...

  17. Diphenylarsinic acid contaminated soil remediation by titanium dioxide (P25) photocatalysis: Degradation pathway, optimization of operating parameters and effects of soil properties.

    PubMed

    Wang, A-nan; Teng, Ying; Hu, Xue-feng; Wu, Long-hua; Huang, Yu-juan; Luo, Yong-ming; Christie, Peter

    2016-01-15

    Diphenylarsinic acid (DPAA) is formed during the leakage of arsenic chemical weapons in sites and poses a high risk to biota. However, remediation methods for DPAA contaminated soils are rare. Here, the photocatalytic oxidation (PCO) process by nano-sized titanium dioxide (TiO2) was applied to degrade DPAA in soil. The degradation pathway was firstly studied, and arsenate was identified as the final product. Then, an orthogonal array experimental design of L9(3)(4), only 9 experiments were needed, instead of 81 experiments in a conventional one-factor-at-a-time, was used to optimize the operational parameters soil:water ratio, TiO2 dosage, irradiation time and light intensity to increase DPAA removal efficiency. Soil:water ratio was found to have a more significant effect on DPAA removal efficiency than other properties. The optimum conditions to treat 4 g soil with a DPAA concentration of 20 mg kg(-1) were found to be a 1:10 soil: water ratio, 40 mW cm(-2) light intensity, 5% TiO2 in soil, and a 3-hour irradiation time, with a removal efficiency of up to 82.7%. Furthermore, this method (except for a change in irradiation time from 3 to 1.5h) was validated in nine different soils and the removal efficiencies ranged from 57.0 to 78.6%. Removal efficiencies were found to be negatively correlated with soil electrical conductivity, organic matter content, pH and total phosphorus content. Finally, coupled with electron spin resonance (ESR) measurement, these soil properties affected the generation of OH• by TiO2 in soil slurry. This study suggests that TiO2 photocatalytic oxidation is a promising treatment for removing DPAA from soil. PMID:26410709

  18. Hydraulic and thermal soil Parameter combined with TEM data at quaternary coastal regions

    NASA Astrophysics Data System (ADS)

    Grabowski, Ima; Kirsch, Reinhard; Scheer, Wolfgang

    2014-05-01

    In order to generate a more efficient method of planning and dimensioning small- and medium sized geothermal power plants at quaternary subsurface a basic approach has been attempted. Within the EU-project CLIWAT, the coastal region of Denmark, Germany, Netherlands and Belgium has been investigated and air borne electro magnetic data was collected. In this work the regional focus was put on the isle of Föhr. To describe the subsurface with relevant parameters one need the information from drillings and geophysical well logging data. The approach to minimize costs and use existing data from state agencies led the investigation to the combination of specific electrical resistivity data and hydraulic and thermal conductivity. We worked out a basic soil/hydraulic conductivity statistic for the isle of Föhr by gathering all well logging data from the island and sorted the existing soil materials to associated kf -values. We combined specific electrical resistivity with hydraulic soil properties to generate thermal conductivity values by extracting porosity. Until now we generated a set of rough data for kf - values and thermal conductivity. The air borne TEM data sets are reliable up to 150 m below surface, depending on the conductivity of the layers. So we can suppose the same for the differentiated parameters. Since this is a very rough statistic of kf -values, further more investigation has to be made. Although the close connection to each area of investigation either over existing logging data or laboratory soil property values will remain necessary. Literature: Ahmed S, de Marsily G, Talbot A (1988): Combined Use of Hydraulic and Electrical Properties of an Aquifer in a Geostatistical Estimation of Transmissivity. - Groundwater, vol. 26 (1) Burschil T, Scheer W, Wiederhold H, Kirsch R (2012): Groundwater situation on a glacially affected barrier island. Submitted to Hydrology and Earth System Sciences - an Interactive Open Access Journal of the European

  19. The spatiotemporal characteristics of soil physio-chemical parameters and their influence on cotton growth under mulched drip irrigation

    NASA Astrophysics Data System (ADS)

    Hu, H.; Tian, F.; Zhang, Z.; Hu, H.

    2013-12-01

    The spatiotemporal characteristics of the physio-chemical parameters of soil and their impacts on crop growth are the key issues affecting precision agriculture. However, quantitative research in cotton fields under mulched drip irrigation is rare. One hundred experimental plots (6 m× 6 m) were set up for the above purpose in an agricultural experimental field in Xinjiang Uygur Autonomous Region of China. Soil samples were collected to measure the soil texture, moisture and salinity at depths of 5, 10, 20, 30, 50 and 80 cm in the near-tape zone and the inter-film zone in each experimental plot in March, April, June and September of 2012. The number and height of the cotton plants in June and the yield of cotton in September were also surveyed in 3 sample units (75 cm × 75 cm) in each experimental plot. The results indicate that the soil composition of clay and silt was highest at a soil depth of 5 to 20 cm due to the cultivation practices, and the Cv (coefficient of variation) values of soil texture increased with depth. The spring flush led to an 8% decrease in soil salinity and reduced the Cv values of soil salinity, soil moisture and soil texture. The Cv values of soil salinity and soil moisture increased as mulched drip irrigation was applied. The Cv values of soil salinity and moisture under the near tape zone were higher than under the interfilm zone; the difference was up to twofold in September. The validity of a theoretical semivariogram model of soil moisture is greater than that of texture, soil salinity and crop trait when comparing the estimation of the theoretical semivariogram with measured values. The influence of soil physiochemical characteristics on the number of cotton plants is largest in April, and their influence on the height of cotton plants is greatest in June. However, the influence of soil physiochemical characteristics on cotton yield is smaller than that on cotton number and height in April and June. The soil salt under the near tape

  20. Influence of rhizosphere microbial ecophysiological parameters from different plant species on butachlor degradation in a riparian soil.

    PubMed

    Yang, Changming; Wang, Mengmeng; Li, Jianhua

    2012-01-01

    Biogeochemical processes in riparian zones regulate contaminant movement to receiving waters and often mitigate the impact of upland sources of contaminants on water quality. However, little research has been reported on the microbial process and degradation potential of herbicide in a riparian soil. Field sampling and incubation experiments were conducted to investigate differences in microbial parameters and butachlor degradation in the riparian soil from four plant communities in Chongming Island, China. The results suggested that the rhizosphere soil had significantly higher total organic C and water-soluble organic C relative to the nonrhizosphere soil. Differences in rhizosphere microbial community size and physiological parameters among vegetation types were significant. The rhizosphere soil from the mixed community of Phragmites australis and Acorus calamus had the highest microbial biomass and biochemical activity, followed by A. calamus, P. australis and Zizania aquatica. Microbial ATP, dehydrogenase activity (DHA), and basal soil respiration (BSR) in the rhizosphere of the mixed community of P. australis and A. calamus were 58, 72, and 62% higher, respectively, than in the pure P. australis community. Compared with the rhizosphere soil of the pure plant communities, the mixed community of P. australis and A. calamus displayed a significantly greater degradation rate of butachlor in the rhizosphere soil. Residual butachlor concentrations in rhizosphere soil of the mixed community of P. australis and A. calamus and were 48, 63, and 68% lower than three pure plant communities, respectively. Butachlor degradation rates were positively correlated to microbial ATP, DHA, and BSR, indicating that these microbial parameters may be useful in assessing butachlor degradation potential in the riparian soil. PMID:22565253

  1. High resolution petrophysical and geomechanical logging of drill cores as a tool for the evaluation of dimension stone quality and durability

    NASA Astrophysics Data System (ADS)

    Prikryl, Richard; Lokajíček, Tomáš; Weishauptová, Zuzana; Petružálek, Matěj

    2015-04-01

    Petrophysical and geomechanical properties are significant functional properties of natural stone. In the recent study, an approach employing the entire non-disturb parts of drill cores for determination of the key petrophysical and geomechanical parameters is presented. The drill cores have been obtained during exploration campaign for Carboniferous arkoses and arkosic sandstones to conglomerates in the Bohemian Massif (Czech Republic). The test procedure consists of the sequence of non-destructive methods including determination of index properties, ultrasonic characteristics (speed of longitudinal and transversal waves, recording of the full waveforms). Once non-destructively tested, the specimens are subjected to standard compressive and/or tensile tests encompassing recording of stress-strain behaviour. Broad range of values obtained reflects quite complex petrographical character of rocks investigated. Variable grain size, grain size homogeneity, degree of cementation, overall rock microfabric, and/or presence and distribution of inter- and intraparticle porosity seem to be determinative factors. Once calibrated for a particular petrographical characteristics, high resolution petrophysical and geomechanical logging (HRPGL) can serve as an effective tool for precise evaluation of exploitable natural stone quality.

  2. Projecting the release of carbon from permafrost soils using a perturbed parameter ensemble modelling approach

    NASA Astrophysics Data System (ADS)

    MacDougall, Andrew H.; Knutti, Reto

    2016-04-01

    The soils of the northern hemispheric permafrost region are estimated to contain 1100 to 1500 Pg of carbon. A substantial fraction of this carbon has been frozen and therefore protected from microbial decay for millennia. As anthropogenic climate warming progresses much of this permafrost is expected to thaw. Here we conduct perturbed model experiments on a climate model of intermediate complexity, with an improved permafrost carbon module, to estimate with formal uncertainty bounds the release of carbon from permafrost soils by the year 2100 and 2300 CE. We estimate that by year 2100 the permafrost region may release between 56 (13 to 118) Pg C under Representative Concentration Pathway (RCP) 2.6 and 102 (27 to 199) Pg C under RCP 8.5, with substantially more to be released under each scenario by the year 2300. Our analysis suggests that the two parameters that contribute most to the uncertainty in the release of carbon from permafrost soils are the size of the non-passive fraction of the permafrost carbon pool and the equilibrium climate sensitivity. A subset of 25 model variants are integrated 8000 years into the future under continued RCP forcing. Under the moderate RCP 4.5 forcing a remnant near-surface permafrost region persists in the high Arctic, eventually developing a new permafrost carbon pool. Overall our simulations suggest that the permafrost carbon cycle feedback to climate change will make a significant contribution to climate change over the next centuries and millennia, releasing a quantity of carbon 3 to 54 % of the cumulative anthropogenic total.

  3. Mechanical and petrophysical study of fractured shale materials

    NASA Astrophysics Data System (ADS)

    Bonnelye, A.; Schubnel, A.; David, C.; Henry, P.; Guglielmi, Y.; Gout, C.; Dick, P.

    2013-12-01

    Understanding of the mechanical and physical properties of shales is of major importance in many fields such as faults hydro-mechanical behavior, cap-rock and unconventional reservoir studies or nuclear waste disposal. In particular, relationships between fluid transport properties, applied stress and textural anisotropy are critical both in intact and fractured shales. Therefore, these relations need to be investigated in the laboratory in order to have a better understanding on in-situ mechanisms. Hence, the mechanical behavior and the petrophysical properties of Toarcian shale of the Tournemire underground laboratory (France) have been investigated. The petrophysical properties have been measured along a 20 meters core drilled through a fault zone from the Tournemire tunnel. Along the core, P and S waves velocity and anisotropy, as well as magnetic susceptibility anisotropy and porosity were measured. In addition, conventional triaxial tests have been performed in order to determine the elasto-plastic yield envelope on three sets of samples with different orientations relative to bedding (0°, 45°, and 90° to the vertical axe). For each set, six experiments were carried out at increasing confining pressures (2.5, 5, 10, 20, 40, 80MPa). Experiments were performed in dry conditions, at a strain rate of 5x10-7 s-1 up to failure. During each experiment, P and S wave elastic velocities were continuously measured along different directions, in order to assess both P wave anisotropy and shear wave splitting and their evolutions with deformation. Our results show that brittle failure is preceded by the development of P wave anisotropy and shear wave splitting, due to crack re-opening and crack growth. However, the orientation of principal stress components relative to the bedding plane plays an important role on both the brittle strength, as well as on the magnitude of shear-enhanced P wave velocity anisotropy and S wave splitting. Our perspective is now to perform

  4. Small scale variability of soil parameters in different land uses on the southern slopes of Mount Kilimanjaro

    NASA Astrophysics Data System (ADS)

    Bogner, Christina; Kühnel, Anna; Hepp, Johannes; Huwe, Bernd

    2016-04-01

    The Kilimanjaro region in Tanzania constitutes a particularity compared to other areas in the country. Because enough water is available the population grows rapidly and large areas are converted from natural ecosystems to agricultural areas. Therefore, the southern slopes of Mt. Kilimanjaro encompass a complex mosaic of different land uses like coffee plantations, maize, agroforestry or natural savannah. Coffee is an important cash crop in the region and is owned mostly by large companies. In contrast, the agroforestry is a traditional way of agriculture and has been sustained by the Chagga tribe for centuries. These so called homegardens are organised as multi-level systems and contain a mixture of different crops. Correlations in soil and vegetation data may serve as indicators for crop and management impacts associated to different types of land use. We hypothesize that Chagga homegardens, for example, show a more pronounced spatial autocorrelation compared to coffee plantations due to manifold above and belowground crop structures, whereas the degree of anisotropy is assumed to be higher in the coffee sites due to linear elements in management. Furthermore, we hypothesize that the overall diversity of soil parameters in homegardens on a larger scale is higher, as individual owners manage their field differently, whereas coffee plantation management often follows general rules. From these general hypotheses we derive two specific research questions: a) Are there characteristic differences in the spatial organisation of soil physical parameters of different land uses? b) Is there a recognizable relationship between vegetation structure and soil physical parameters of topsoils? We measured soil physical parameters in the topsoil (bulk density, stone content, texture, soil moisture and penetration resistance). Additionally, we took spectra of soil samples with a portable VIS-NIR spectrometer to determine C and N and measured leaf area index and troughfall as an

  5. A sensitivity analysis of hazardous waste disposal site climatic and soil design parameters using HELP3

    SciTech Connect

    Adelman, D.D.; Stansbury, J.

    1997-12-31

    The Resource Conservation and Recovery Act (RCRA) Subtitle C, Comprehensive Environmental Response, Compensation, And Liability Act (CERCLA), and subsequent amendments have formed a comprehensive framework to deal with hazardous wastes on the national level. Key to this waste management is guidance on design (e.g., cover and bottom leachate control systems) of hazardous waste landfills. The objective of this research was to investigate the sensitivity of leachate volume at hazardous waste disposal sites to climatic, soil cover, and vegetative cover (Leaf Area Index) conditions. The computer model HELP3 which has the capability to simulate double bottom liner systems as called for in hazardous waste disposal sites was used in the analysis. HELP3 was used to model 54 combinations of climatic conditions, disposal site soil surface curve numbers, and leaf area index values to investigate how sensitive disposal site leachate volume was to these three variables. Results showed that leachate volume from the bottom double liner system was not sensitive to these parameters. However, the cover liner system leachate volume was quite sensitive to climatic conditions and less sensitive to Leaf Area Index and curve number values. Since humid locations had considerably more cover liner system leachate volume than and locations, different design standards may be appropriate for humid conditions than for and conditions.

  6. Massively Parallel Computation of Soil Surface Roughness Parameters on A Fermi GPU

    NASA Astrophysics Data System (ADS)

    Li, Xiaojie; Song, Changhe

    2016-06-01

    Surface roughness is description of the surface micro topography of randomness or irregular. The standard deviation of surface height and the surface correlation length describe the statistical variation for the random component of a surface height relative to a reference surface. When the number of data points is large, calculation of surface roughness parameters is time-consuming. With the advent of Graphics Processing Unit (GPU) architectures, inherently parallel problem can be effectively solved using GPUs. In this paper we propose a GPU-based massively parallel computing method for 2D bare soil surface roughness estimation. This method was applied to the data collected by the surface roughness tester based on the laser triangulation principle during the field experiment in April 2012. The total number of data points was 52,040. It took 47 seconds on a Fermi GTX 590 GPU whereas its serial CPU version took 5422 seconds, leading to a significant 115x speedup.

  7. Improving the Operability of the Cosmic-ray Neutron Soil Moisture Method: Estimation of Soil Calibration Parameters Using Global Datasets

    NASA Astrophysics Data System (ADS)

    Finkenbiner, C. E.; Avery, W. A.; Franz, T. E.; Munoz-Arriola, F.; Rosolem, R.

    2014-12-01

    Despite its critical importance to global food security, approximately 60% of water used for agriculture is wasted each year through inadequate water conservation, losses in distribution, and inefficient irrigation. Therefore, in order to coordinate a strategy to accomplish the agricultural demands in the future we must maintain a stable global food and water trade while increasing crop yield and efficiency. This research aims to improve the operability of the novel cosmic-ray neutron method used for estimating field scale soil moisture. The sensor works by passively counting the above ground low-energy neutrons which correlates to the amount of water in the measurement volume (a circle with radius of ~300 m and vertical depth of ~30 cm). Because the sensor responds to different forms of water (sources of hydrogen), estimates of background water in the mineral soil and soil organic matter must be accounted in order to minimize measurement error. Here we compared field-scale estimates of soil mineral water and soil organic matter with readily available global datasets. Using the newly compiled 1 km resolution Global Soil Dataset (GSDE), we investigate the correlation between (1) soil mineral water and clay content and (2) in-situ soil organic material. Preliminary results of in-situ samples from forty study sites around the globe suggest the GSDE dataset has sufficiently low bias and uncertainty (~ within 0.01 g/g of water equivalent) to better isolate the soil moisture signal from the neutron count information. Incorporation of this dataset will allow for real-time soil moisture mapping of hundreds of center-pivots using the mobile cosmic-ray sensor without the need of time-consuming in-situ soil sampling. The incorporation of this novel technique for soil moisture management has the potential to increase the efficiency of irrigation water use.

  8. Soil quality parameters for row-crop and grazed pasture systems with agroforestry buffers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Incorporation of trees and establishment of buffers are practices that can improve soil quality. Soil enzyme activities and water stable aggregates are sensitive indices for assessing soil quality by detecting early changes in soil management. However, studies comparing grazed pasture and row crop...

  9. Spatial effects of aboveground biomass on soil ecological parameters and trace gas fluxes in a savannah ecosystem of Mount Kilimanjaro

    NASA Astrophysics Data System (ADS)

    Becker, Joscha; Gütlein, Adrian; Sierra Cornejo, Natalia; Kiese, Ralf; Hertel, Dietrich; Kuzyakov, Yakov

    2015-04-01

    The savannah biome is a hotspot for biodiversity and wildlife conservation in Africa and recently got in the focus of research on carbon sequestration. Savannah ecosystems are under strong pressure from climate and land-use change, especially around populous areas like the Mt. Kilimanjaro region. Savannah vegetation in this area consists of grassland with isolated trees and is therefore characterized by high spatial variation of canopy cover, aboveground biomass and root structure. Canopy structure is known to affect microclimate, throughfall and evapotranspiration and thereby controls soil moisture conditions. Consequently, the canopy structure is a major regulator for soil ecological parameters and soil-atmospheric trace gas exchange (CO2, N2O, CH4) in water limited environments. The spatial distribution of these parameters and the connection between above and belowground processes are important to understand and predict ecosystem changes and estimate its vulnerability. Our objective was to determine trends and changes of soil parameters and relate their spatial variability to the vegetation structure. We chose three trees from each of the two most dominant species (Acacia nilotica and Balanites aegyptiaca) in our research area. For each tree, we selected transects with nine sampling points of the same relative distances to the stem. Distances were calculated in relation to the crown radius. At these each sampling point a soil core was taken and separated in 0-10 cm and 10-30 cm depth. We measured soil carbon (C) and nitrogen (N) storage, microbial biomass carbon C and N, soil respiration as well as root biomass and -density, soil temperature and soil water content. Each tree was characterized by crown spread, leaf area index and basal area. Preliminary results show that C and N stocks decreased about 50% with depth independently of distance to the tree. Soil water content under the tree crown increased with depth while it decreased under grass cover. Microbial

  10. Optimization of hydrological parameters in a Soil-Tree-Atmosphere Continuum model of a large White Fir

    NASA Astrophysics Data System (ADS)

    Rings, J.; Kamai, T.; Mollaei Kandelous, M.; Nasta, P.; Vrugt, J. A.; Hartsough, P. C.; Hopmans, J. W.

    2011-12-01

    We use statistical optimization with a hydrologic model to obtain the van Genuchten parameters of a large White Fir tree in a mid-latitude montane forest ecosystem, located in the King's River Experimental Watershed as part of the Southern Sierra Critical Zone Observatory. The site is instrumented for spatially distributed monitoring of soil water content, matric potential and sap flux. The physical tree is represented in a HYDRUS model that models the interactions betweens soil, tree and atmosphere as a continuum. The soil and tree domains are modeled as variably saturated porous media, while atmospheric forcing taken from a nearby flux tower is used to determine the potential evapotranspiration (ET) and root uptake (RU). Actual ET and RU are modeled by accounting for canopy and root distributions together with matric potential stress in the soil-tree domains. This model is embedded within a Markov Chain Monte Carlo (MCMC) framework using current versions of the DREAM_ZS optimization code. We present results of the parameter optimization for time periods in different seasons, analyze the uncertainty and information content in the different measurement methods and use the optimized parameters to study the influence of soil water stress on the soil-root-tree system.

  11. Physical basis and potential estimation techniques for soil erosion parameters in the Precipitation-Runoff Modeling System (PRMS)

    USGS Publications Warehouse

    Carey, W.P.; Simon, Andrew

    1984-01-01

    Simulation of upland-soil erosion by the Precipitation-Runoff Modeling System currently requires the user to estimate two rainfall detachment parameters and three hydraulic detachmment paramenters. One rainfall detachment parameter can be estimated from rainfall simulator tests. A reformulation of the rainfall detachment equation allows the second parameter to be computed directly. The three hydraulic detachment parameters consist of one exponent and two coefficients. The initial value of the exponent is generally set equal to 1.5. The two coefficients are functions of the soil 's resistance to erosion and one of the two also accounts for sediment delivery processes not simulated in the model. Initial estimates of these parameters can be derived from other modeling studies or from published empirical relations. (USGS)

  12. Specific microbial gene abundances and soil parameters contribute to C, N, and greenhouse gas process rates after land use change in Southern Amazonian Soils.

    PubMed

    Lammel, Daniel R; Feigl, Brigitte J; Cerri, Carlos C; Nüsslein, Klaus

    2015-01-01

    Ecological processes regulating soil carbon (C) and nitrogen (N) cycles are still poorly understood, especially in the world's largest agricultural frontier in Southern Amazonia. We analyzed soil parameters in samples from pristine rainforest and after land use change to pasture and crop fields, and correlated them with abundance of functional and phylogenetic marker genes (amoA, nirK, nirS, norB, nosZ, nifH, mcrA, pmoA, and 16S/18S rRNA). Additionally, we integrated these parameters using path analysis and multiple regressions. Following forest removal, concentrations of soil C and N declined, and pH and nutrient levels increased, which influenced microbial abundances and biogeochemical processes. A seasonal trend was observed, suggesting that abundances of microbial groups were restored to near native levels after the dry winter fallow. Integration of the marker gene abundances with soil parameters using path analysis and multiple regressions provided good predictions of biogeochemical processes, such as the fluxes of NO3, N2O, CO2, and CH4. In the wet season, agricultural soil showed the highest abundance of nitrifiers (amoA) and Archaea, however, forest soils showed the highest abundances of denitrifiers (nirK, nosZ) and high N, which correlated with increased N2O emissions. Methanogens (mcrA) and methanotrophs (pmoA) were more abundant in forest soil, but methane flux was highest in pasture sites, which was related to soil compaction. Rather than analyzing direct correlations, the data integration using multivariate tools provided a better overview of biogeochemical processes. Overall, in the wet season, land use change from forest to agriculture reduced the abundance of different functional microbial groups related to the soil C and N cycles; integrating the gene abundance data and soil parameters provided a comprehensive overview of these interactions. Path analysis and multiple regressions addressed the need for more comprehensive approaches to improve our

  13. Specific microbial gene abundances and soil parameters contribute to C, N, and greenhouse gas process rates after land use change in Southern Amazonian Soils

    PubMed Central

    Lammel, Daniel R.; Feigl, Brigitte J.; Cerri, Carlos C.; Nüsslein, Klaus

    2015-01-01

    Ecological processes regulating soil carbon (C) and nitrogen (N) cycles are still poorly understood, especially in the world’s largest agricultural frontier in Southern Amazonia. We analyzed soil parameters in samples from pristine rainforest and after land use change to pasture and crop fields, and correlated them with abundance of functional and phylogenetic marker genes (amoA, nirK, nirS, norB, nosZ, nifH, mcrA, pmoA, and 16S/18S rRNA). Additionally, we integrated these parameters using path analysis and multiple regressions. Following forest removal, concentrations of soil C and N declined, and pH and nutrient levels increased, which influenced microbial abundances and biogeochemical processes. A seasonal trend was observed, suggesting that abundances of microbial groups were restored to near native levels after the dry winter fallow. Integration of the marker gene abundances with soil parameters using path analysis and multiple regressions provided good predictions of biogeochemical processes, such as the fluxes of NO3, N2O, CO2, and CH4. In the wet season, agricultural soil showed the highest abundance of nitrifiers (amoA) and Archaea, however, forest soils showed the highest abundances of denitrifiers (nirK, nosZ) and high N, which correlated with increased N2O emissions. Methanogens (mcrA) and methanotrophs (pmoA) were more abundant in forest soil, but methane flux was highest in pasture sites, which was related to soil compaction. Rather than analyzing direct correlations, the data integration using multivariate tools provided a better overview of biogeochemical processes. Overall, in the wet season, land use change from forest to agriculture reduced the abundance of different functional microbial groups related to the soil C and N cycles; integrating the gene abundance data and soil parameters provided a comprehensive overview of these interactions. Path analysis and multiple regressions addressed the need for more comprehensive approaches to improve

  14. Integration of seismic and petrophysics to characterize reservoirs in "ALA" oil field, Niger Delta.

    PubMed

    Alao, P A; Olabode, S O; Opeloye, S A

    2013-01-01

    In the exploration and production business, by far the largest component of geophysical spending is driven by the need to characterize (potential) reservoirs. The simple reason is that better reservoir characterization means higher success rates and fewer wells for reservoir exploitation. In this research work, seismic and well log data were integrated in characterizing the reservoirs on "ALA" field in Niger Delta. Three-dimensional seismic data was used to identify the faults and map the horizons. Petrophysical parameters and time-depth structure maps were obtained. Seismic attributes was also employed in characterizing the reservoirs. Seven hydrocarbon-bearing reservoirs with thickness ranging from 9.9 to 71.6 m were delineated. Structural maps of horizons in six wells containing hydrocarbon-bearing zones with tops and bottoms at range of -2,453 to -3,950 m were generated; this portrayed the trapping mechanism to be mainly fault-assisted anticlinal closures. The identified prospective zones have good porosity, permeability, and hydrocarbon saturation. The environments of deposition were identified from log shapes which indicate a transitional-to-deltaic depositional environment. In this research work, new prospects have been recommended for drilling and further research work. Geochemical and biostratigraphic studies should be done to better characterize the reservoirs and reliably interpret the depositional environments. PMID:24068883

  15. Integration of Seismic and Petrophysics to Characterize Reservoirs in “ALA” Oil Field, Niger Delta

    PubMed Central

    Alao, P. A.; Olabode, S. O.; Opeloye, S. A.

    2013-01-01

    In the exploration and production business, by far the largest component of geophysical spending is driven by the need to characterize (potential) reservoirs. The simple reason is that better reservoir characterization means higher success rates and fewer wells for reservoir exploitation. In this research work, seismic and well log data were integrated in characterizing the reservoirs on “ALA” field in Niger Delta. Three-dimensional seismic data was used to identify the faults and map the horizons. Petrophysical parameters and time-depth structure maps were obtained. Seismic attributes was also employed in characterizing the reservoirs. Seven hydrocarbon-bearing reservoirs with thickness ranging from 9.9 to 71.6 m were delineated. Structural maps of horizons in six wells containing hydrocarbon-bearing zones with tops and bottoms at range of −2,453 to −3,950 m were generated; this portrayed the trapping mechanism to be mainly fault-assisted anticlinal closures. The identified prospective zones have good porosity, permeability, and hydrocarbon saturation. The environments of deposition were identified from log shapes which indicate a transitional-to-deltaic depositional environment. In this research work, new prospects have been recommended for drilling and further research work. Geochemical and biostratigraphic studies should be done to better characterize the reservoirs and reliably interpret the depositional environments. PMID:24068883

  16. Petrophysical and paleomagnetic data of drill cores from the Bosumtwi impact structure, Ghana

    NASA Astrophysics Data System (ADS)

    Elbra, T.; Kontny, A.; Pesonen, L. J.; Schleifer, N.; Schell, C.

    Physical properties from rocks of the Bosumtwi impact structure, Ghana, Central Africa, are essential to understand the formation of the relatively young (1.07 Ma) and small (10.5 km) impact crater and to improve its geophysical modeling. Results of our petrophysical studies of deep drill cores LB-07A and LB-08A reveal distinct lithological patterns but no depth dependence. The most conspicuous difference between impactites and target lithologies are the lower bulk densities and significantly higher porosities of the suevite and lithic breccia units compared to meta-graywacke and metapelites of target lithologies. Magnetic susceptibility shows mostly paramagnetic values (200-500 × 10-6 SI) throughout the core, with an exception of a few metasediment samples, and correlates positively with natural remanent magnetization (NRM) and Q values. These data indicate that magnetic parameters are related to inhomogeneously distributed ferrimagnetic pyrrhotite. The paleomagnetic data reveals that the characteristic direction of NRM has shallow normal (in a few cases shallow reversed) polarity, which is in agreement with the Lower Jaramillo N-polarity chron direction, and is carried by ferrimagnetic pyrrhotite. However, our study has not revealed the expected high magnetization body required from previous magnetic modeling. Furthermore, the LB-07A and LB08-A drill cores did not show the predicted high content of melt in the rocks, requiring a new interpretation model for magnetic data.

  17. Fuzzy ruling between core porosity and petrophysical logs: Subtractive clustering vs. genetic algorithm-pattern search

    NASA Astrophysics Data System (ADS)

    Bagheripour, Parisa; Asoodeh, Mojtaba

    2013-12-01

    Porosity, the void portion of reservoir rocks, determines the volume of hydrocarbon accumulation and has a great control on assessment and development of hydrocarbon reservoirs. Accurate determination of porosity from core analysis is highly cost, time, and labor intensive. Therefore, the mission of finding an accurate, fast and cheap way of determining porosity is unavoidable. On the other hand, conventional well log data, available in almost all wells contain invaluable implicit information about the porosity. Therefore, an intelligent system can explicate this information. Fuzzy logic is a powerful tool for handling geosciences problem which is associated with uncertainty. However, determination of the best fuzzy formulation is still an issue. This study purposes an improved strategy, called hybrid genetic algorithm-pattern search (GA-PS) technique, against the widely held subtractive clustering (SC) method for setting up fuzzy rules between core porosity and petrophysical logs. Hybrid GA-PS technique is capable of extracting optimal parameters for fuzzy clusters (membership functions) which consequently results in the best fuzzy formulation. Results indicate that GA-PS technique manipulates both mean and variance of Gaussian membership functions contrary to SC that only has a control on mean of Gaussian membership functions. A comparison between hybrid GA-PS technique and SC method confirmed the superiority of GA-PS technique in setting up fuzzy rules. The proposed strategy was successfully applied to one of the Iranian carbonate reservoir rocks.

  18. Determination of Strength Parameters of Soil Samples Recovered from Eastern Nankai Trough for Seafloor Stability Study

    NASA Astrophysics Data System (ADS)

    Nishio, S.; Ogisako, E.; Denda, A.; Mitachi, T.; Hirakawa, H.

    2014-12-01

    In Japan, the interest in methane hydrate is increasing rapidly owing to increasing recognition of its potential as a next-generation energy resource that can replace conventional fossil fuels. To produce methane gas safely and minimize the associated environmental damage, we need to address many wide-ranging environmental issues. One such issue entails assessing seafloor stability during methane gas production. Methane hydrate binds the sand grains that make up the strata under the seafloor. It has been suggested that methane production may lead to seafloor deformation because the strata become unstable following the removal of methane hydrate. The geotechnical properties of ground have significant effects on its deformation behavior, but deep seafloors have not been thoroughly investigated yet. The world's first offshore test gas production from methane hydrate was conducted in the eastern Nankai Trough. We present geotechnical properties of the samples recovered from the gas production site; these properties were determined by means of laboratory tests. Soil index tests, consolidation tests, K0 consolidated undrained triaxial compression/extension tests and direct box shear tests were conducted for obtaining the geotechnical parameters necessary for deep seafloor stability analysis. The strength parameters corresponding to peak and residual states were determined by the reversal direct box shear tests. This study is supported by the Research Consortium for Methane Hydrate Resources in Japan. We wish to express our appreciation to the MH21 Research Consortium and Japan Oil, Gas and Metals National Corporation for their permission to use the laboratory test data.

  19. Indirect estimation of calibration equation parameters for Sentek Diviner 2000 capacitance probe by means of soil physical properties

    NASA Astrophysics Data System (ADS)

    Rallo, Giovanni; Provenzano, Giuseppe

    2014-05-01

    Measurements of soil water content (SWC) are often used for irrigation scheduling. Accurate monitoring of SWC is necessary, for example, to identify the exact irrigation timing and the amount of water volume to supply according to the crop requirement. The use of capacitance probes, measuring the apparent soil dielectric permittivity, indirectly related to soil water status, have been increasing during the last decade, as proved by the numerous researches carried out to determine, for different soil types, site-specific calibration relationships between SWC and the scaled frequency (SF) measured by the sensor. However, for swelling/shrinking clay soils, there is a lack of knowledge on how the changes of soil bulk density associated to variations of soil water content influence the apparent dielectric permittivity and therefore the sensor calibration relationship, as a consequence of the different contribute that soil, water and air, have on the measure provided by the sensor. The main objectives of the work are i) to determine the site specific calibration equations for a Sentek Diviner 2000 capacitance probe for soils characterized by different texture, ii) to investigate on the effects of soil bulk density and its variability with soil water content, on the calibration equation and iii) to proceed to the indirect estimation of calibration parameters by means of easily-measurable soil physical properties. Experiments were carried out on nine different soils collected from Sicilian irrigated area, characterized by a clay percentage ranging between 9% and 45%. Undisturbed soil samples (25 cm diameter and 25 cm height), allowed to determine, for each soil, the corresponding site-specific calibration equation. On the other hands, samples having the same dimensions, but filled with sieved soil and compacted at two different bulk densities (ρb), were used to investigate on the effects of soil texture and bulk density on the measured SF. On each undisturbed or sieved

  20. Assessment of fly ash-aided phytostabilisation of highly contaminated soils after an 8-year field trial: part 1. Influence on soil parameters and metal extractability.

    PubMed

    Lopareva-Pohu, Alena; Pourrut, Bertrand; Waterlot, Christophe; Garçon, Guillaume; Bidar, Géraldine; Pruvot, Christelle; Shirali, Pirouz; Douay, Francis

    2011-01-01

    Sustainable management of large surface areas contaminated with trace elements is a real challenge, since currently applied remediation techniques are too expensive for these areas. Aided phytostabilisation appears to be a cost efficient technique to reduce metal mobility in contaminated soils and contaminated particle spread. In this context, this study aimed at evaluating the long-term efficiency of aided phytostabilisation on former agricultural soils highly contaminated with trace elements. The influence of afforestation and fly ash amendments to reduce metal mobility was investigated. Before being planted with a tree mix, the study site was divided into three plots: a reference plot with no amendment, the second amended with silico-aluminous fly ash and the third with sulfo-calcic fly ash. After eight years, some soil physico-chemical parameters, including cadmium (Cd), lead (Pb) and zinc (Zn) extractability were modified. In particular, pH decreased on the whole site while organic carbon content increased. The alteration of these parameters influencing trace element mobility is explained by afforestation. Over time, concentrations of CaCl(2)-extractable metals increased and were correlated with the soil pH decrease. In the amended soils, extractable Cd, Pb and Zn concentrations were lower than in the reference soil. The results indicated that the two fly ashes buffered natural soil acidification due to vegetation development and limited trace element mobility and thus could limit their bioavailability. For long-term phytostabilisation, special attention should be focused on the soil pH, metal mobility and phytoavailability analysis. PMID:21106226

  1. Analysis of physical parameters related with water infiltration in tropical soils located in edges forest in urban areas

    NASA Astrophysics Data System (ADS)

    Márcia Longo, Regina; Cunha, Jessica C. M.; Lammoglia, Rafaella; Mendes, Deborah R.; Mungilioli, Sarah S.; Damame, Desiree B.; Demamboro, Antônio C.; Bettine, Sueli C.; Ribeiro, Admilson I.; Fengler, Felipe H.

    2015-04-01

    A very important factor for water infiltration into the soil in urban forest systems and suffering constant anthropogenic pressures is the analysis of soil compaction where these forests are or will be established. In this context, this work aimed to promote studies on physical parameters related to distribution of pores, compaction and soil biological activity in forest remnants border areas located in urban watersheds in Campinas / SP - Brazil. The Forest of Santa Genebra (22°49'45 "S and 47°06'33" W) has an average altitude of 680m and tropical climate of altitude, has an area of 251 ha and a nine kilometer perimeter. It constitutes 85% of Semideciduos forests and 15% swamp forest. Due to its location close to urban centers, roads and agricultural areas under direct influence of the anthropic means. For the present study analyzes were performed: particle size, soil density, porosity, matters organic, of biopores, and root distribution (primary, secondary and tertiary) and seedlings in 40 points on the perimeter of the forest equidistant 200m remaining edge. The analysis of the results allowed us to observe that areas suffer direct influence of human activities surrounding. With the results set correlations between the different parameters in order to allow a better understanding of the dynamics of water infiltration into the soil under these conditions and the quantity of tertiary roots, biopores and soil density were the best indicator of environmental quality as suffer direct influence of the surrounding areas, especially those near the most urbanized regions. In general, it can be observed that human activities such as deforestation and vehicle traffic, animals and people, promoted soil compaction and consequent changes in water infiltration into the soil in areas of edges of this remnant of these consequences affect direct numerous parameters that directly influence the dynamics of an ecosystem restoration that is now significantly affected by the

  2. Estimation of Bare Surface Soil Moisture and Surface Roughness Parameter Using L-Band SAR Image Data

    NASA Technical Reports Server (NTRS)

    Shi, Jian-Cheng; Wang, James; Hsu, Ann Y.; ONeill, Peggy E.; Engman, Edwin T.

    1997-01-01

    An algorithm based on a fit of the single-scattering Integral Equation Method (IEM) was developed to provide estimation of soil moisture and surface roughness parameter (a combination of rms roughness height and surface power spectrum) from quad-polarized synthetic aperture radar (SAR) measurements. This algorithm was applied to a series of measurements acquired at L-band (1.25 GHz) from both AIRSAR (Airborne Synthetic Aperture Radar operated by the Jet Propulsion Laboratory) and SIR-C (Spaceborne Imaging Radar-C) over a well- managed watershed in southwest Oklahoma. Prior to its application for soil moisture inversion, a good agreement was found between the single-scattering IEM simulations and the L band measurements of SIR-C and AIRSAR over a wide range of soil moisture and surface roughness conditions. The sensitivity of soil moisture variation to the co-polarized signals were then examined under the consideration of the calibration accuracy of various components of SAR measurements. It was found that the two co-polarized backscattering coefficients and their combinations would provide the best input to the algorithm for estimation of soil moisture and roughness parameter. Application of the inversion algorithm to the co-polarized measurements of both AIRSAR and SIR-C resulted in estimated values of soil moisture and roughness parameter for bare and short-vegetated fields that compared favorably with those sampled on the ground. The root-mean-square (rms) errors of the comparison were found to be 3.4% and 1.9 dB for soil moisture and surface roughness parameter, respectively.

  3. The benefits of using remotely sensed soil moisture in parameter identification of large-scale hydrological models

    NASA Astrophysics Data System (ADS)

    Karssenberg, D.; Wanders, N.; de Roo, A.; de Jong, S.; Bierkens, M. F.

    2013-12-01

    Large-scale hydrological models are nowadays mostly calibrated using observed discharge. As a result, a large part of the hydrological system that is not directly linked to discharge, in particular the unsaturated zone, remains uncalibrated, or might be modified unrealistically. Soil moisture observations from satellites have the potential to fill this gap, as these provide the closest thing to a direct measurement of the state of the unsaturated zone, and thus are potentially useful in calibrating unsaturated zone model parameters. This is expected to result in a better identification of the complete hydrological system, potentially leading to improved forecasts of the hydrograph as well. Here we evaluate this added value of remotely sensed soil moisture in calibration of large-scale hydrological models by addressing two research questions: 1) Which parameters of hydrological models can be identified by calibration with remotely sensed soil moisture? 2) Does calibration with remotely sensed soil moisture lead to an improved calibration of hydrological models compared to approaches that calibrate only with discharge, such that this leads to improved forecasts of soil moisture content and discharge as well? To answer these questions we use a dual state and parameter ensemble Kalman filter to calibrate the hydrological model LISFLOOD for the Upper Danube area. Calibration is done with discharge and remotely sensed soil moisture acquired by AMSR-E, SMOS and ASCAT. Four scenarios are studied: no calibration (expert knowledge), calibration on discharge, calibration on remote sensing data (three satellites) and calibration on both discharge and remote sensing data. Using a split-sample approach, the model is calibrated for a period of 2 years and validated for the calibrated model parameters on a validation period of 10 years. Results show that calibration with discharge data improves the estimation of groundwater parameters (e.g., groundwater reservoir constant) and

  4. Long-term effect on some chemical parameter and microbial diversity in a conifer forest soil

    NASA Astrophysics Data System (ADS)

    Iglesias, T.; Iglesias, M.; Francisco-Álvarez, R.; Ramírez, M.; Fernández-Bermejo, M. C.

    2009-04-01

    Soil microbiota are one of the soil components most affected by wildfires. The data from the present study were obtained from a conifer forest soil at Sierra de Gredos (Ávila, central Spain) twenty years after fire of low-to-moderate intensity. A set of soil characteristics indicated the extent to which the spontaneous recovery of the soil is produced as a result of vegetation regrowth. Ten months after fire a strong increase in soil pH, organic C and N, and exchangeable Ca and K, with respect the control soil. Eighteen years after this fire it was observed a decrease of soil organic C and N, whereas other variables such as pH, exchangeable Ca and K were slightly increased with respect to control soil. Is summe a change in soil microbiota was observed due to wildfire, with a decrease in fungi and bacteria population, Also some changes in microbial community was detected, Key words: Forest Fire, soil microbiology, chemical soil properties

  5. Online Vegetation Parameter Estimation in Passive Microwave Regime for Soil Moisture Estimation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Remote sensing observations in the passive microwave regime can be used to estimate surface soil moisture over land at global and regional scales. Soil moisture is important to applications such as weather forecasting, climate and agriculture. One approach to estimating soil moisture from remote sen...

  6. Use of airborne hyperspectral imagery to map soil parameters in tilled agricultural fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil hyperspectral reflectance imagery was obtained from an airborne imaging spectrometer (400 to 2450 nm with ~10 nm resolution, 2.5 m spatial resolution) flown over six tilled (bare soil) agricultural fields on the Eastern Shore of the Chesapeake Bay (Queen Anne’s county, MD). Surface soil samples...

  7. Impact of soil parameter and physical process on reproducibility of hydrological processes by land surface model in semiarid grassland

    NASA Astrophysics Data System (ADS)

    Miyazaki, S.; Yorozu, K.; Asanuma, J.; Kondo, M.; Saito, K.

    2014-12-01

    The land surface model (LSM) takes part in the land-atmosphere interaction on the earth system model for the climate change research. In this study, we evaluated the impact of soil parameters and physical process on reproducibility of hydrological process by LSM Minimal Advanced Treatments of Surface Interaction and RunOff (MATSIRO; Takata et al, 2003, GPC) forced by the meteorological data observed at grassland in semiarid climate in China and Mongolia. The testing of MATSIRO was carried out offline mode over the semiarid grassland sites at Tongyu (44.42 deg. N, 122.87 deg. E, altitude: 184m) in China, Kherlen Bayan Ulaan (KBU; 47.21 deg. N, 108.74 deg. E, altitude: 1235m) and Arvaikheer (46.23 N, 102.82E, altitude: 1,813m) in Mongolia. Although all sites locate semiarid grassland, the climate condition is different among sites, which the annual air temperature and precipitation are 5.7 deg. C and 388mm (Tongyu), 1.2 deg.C and 180mm (KBU), and 0.4 deg. C and 245mm(Arvaikheer). We can evaluate the effect of climate condition on the model performance. Three kinds of experiments have been carried out, which was run with the default parameters (CTL), the observed parameters (OBS) for soil physics and hydrology, and vegetation, and refined MATSIRO with the effect of ice in thermal parameters and unfrozen water below the freezing with same parameters as OBS run (OBSr). The validation data has been provided by CEOP(http://www.ceop.net/) , RAISE(http://raise.suiri.tsukuba.ac.jp/), GAME-AAN (Miyazaki et al., 2004, JGR) for Tongyu, KBU, and Arvaikheer, respectively. The reproducibility of the net radiation, the soil temperature (Ts), and latent heat flux (LE) were well reproduced by OBS and OBSr run. The change of soil physical and hydraulic parameter affected the reproducibility of soil temperature (Ts) and soil moisture (SM) as well as energy flux component especially for the sensible heat flux (H) and soil heat flux (G). The reason for the great improvement on the

  8. Hydrogeological, petrophysical and hydrogeochemical characteristics of the groundwater aquifers east of Wadi El-Natrun, Egypt

    NASA Astrophysics Data System (ADS)

    Salem, Zenhom E.; El-Bayumy, Dina A.

    2016-06-01

    The studied water-bearing formations in the investigated area are the Quaternary and the Miocene aquifers. The groundwater movement takes a direction from the eastern and northern directions where the surface water sources are located to the western and southern directions. By comparing the water level data of 1960 and 2010, up to 25 m drawdown was noticed in the southern part due to excessive pumping. On the other hand, water level rising was observed in the same period reaching up to 10 m in the northwestern part due to seepage from the irrigation channel. Petrophysical properties of the studied aquifers were estimated from well logs. The formation water resistivity (Rw) averages 15.2 ohm m whereas the formation factor (F) averages 5.1. The averages of the total porosity, the effective porosity and permeability are 36.5%, 33.1% and 1126.3 mdarcy, respectively. In addition, the gamma ray logs were used to estimate the volume share of shale which showed an average value reached about 34.6%. Total porosity, effective porosity and permeability showed an increasing trend to the northwestern direction where the recharge area is located. The concentrations of TDS and the dissolved elements are higher in the shallow groundwater compared to the deeper one, which could be related to soil salinity and evaporation processes. Ion exchange, water-rock interaction and evaporation processes are the main geochemical processes affecting the chemistry of the studied groundwater. Sodium chloride/bicarbonate types are the most common chemical types in the study area. Most of the water samples are of old meteoric origin (Na2SO4 type) and old marine origin (MgCl2 type). On the basis of SAR and EC values it is concluded that most of the groundwater samples are suitable for irrigation purposes.

  9. Estimation of Bare Surface Soil Moisture and Surface Roughness Parameter Using L-Band SAR Image Data

    NASA Technical Reports Server (NTRS)

    Shi, Jian-Cheng; Wang, James; Hsu, Ann; ONeill, Peggy; Engman, Edwin T.

    1997-01-01

    An algorithm based on a fit of the single-scattering Integral Equation Method (IEM) was developed to provide estimation of soil moisture and surface roughness parameter (a combination of rms roughness height and surface power spectrum) from quasi-polarized synthetic aperture radar (SAR) measurements. This algorithm was applied to a series of measurements acquired at L-band (1.25 GHz) from both AIRSAR (Airborne Synthetic Aperture Radar operated by Jet Propulsion Laboratory) and SIR-C (Spaceborne Imaging Radar-C) over a well-managed watershed in southwest Oklahoma. It was found that the two co-polarized backscattering coefficients and their combinations would provide the best input to the algorithm for estimation of soil moisture and roughness parameter. Application of the inversion algorithm to the co-polarized measurements of both AIRSAR and SIR-C resulted in estimated values of soil moisture and roughness parameter for bare and short-vegetated fields that compared favorably with those sampled on the ground. The root-mean-square (rms) errors of the comparison were found to be 3.4% and 1.9 dB for soil moisture and surface roughness parameter, respectively.

  10. Optimization of Culture Parameters for Maximum Polyhydroxybutyrate Production by Selected Bacterial Strains Isolated from Rhizospheric Soils.

    PubMed

    Lathwal, Priyanka; Nehra, Kiran; Singh, Manpreet; Jamdagni, Pragati; Rana, Jogender S

    2015-01-01

    The enormous applications of conventional non-biodegradable plastics have led towards their increased usage and accumulation in the environment. This has become one of the major causes of global environmental concern in the present century. Polyhydroxybutyrate (PHB), a biodegradable plastic is known to have properties similar to conventional plastics, thus exhibiting a potential for replacing conventional non-degradable plastics. In the present study, a total of 303 different bacterial isolates were obtained from soil samples collected from the rhizospheric area of three crops, viz., wheat, mustard and sugarcane. All the isolates were screened for PHB (Poly-3-hydroxy butyric acid) production using Sudan Black staining method, and 194 isolates were found to be PHB positive. Based upon the amount of PHB produced, the isolates were divided into three categories: high, medium and low producers. Representative isolates from each category were selected for biochemical characterization; and for optimization of various culture parameters (carbon source, nitrogen source, C/N ratio, different pH, temperature and incubation time periods) for maximizing PHB accumulation. The highest PHB yield was obtained when the culture medium was supplemented with glucose as the carbon source, ammonium sulphate at a concentration of 1.0 g/l as the nitrogen source, and by maintaining the C/N ratio of the medium as 20:1. The physical growth parameters which supported maximum PHB accumulation included a pH of 7.0, and an incubation temperature of 30 degrees C for a period of 48 h. A few isolates exhibited high PHB accumulation under optimized conditions, thus showing a potential for their industrial exploitation. PMID:26638531

  11. Indirect estimation of the Convective Lognormal Transfer function model parameters for describing solute transport in unsaturated and undisturbed soil

    NASA Astrophysics Data System (ADS)

    Mohammadi, Mohammad Hossein; Vanclooster, Marnik

    2012-05-01

    Solute transport in partially saturated soils is largely affected by fluid velocity distribution and pore size distribution within the solute transport domain. Hence, it is possible to describe the solute transport process in terms of the pore size distribution of the soil, and indirectly in terms of the soil hydraulic properties. In this paper, we present a conceptual approach that allows predicting the parameters of the Convective Lognormal Transfer model from knowledge of soil moisture and the Soil Moisture Characteristic (SMC), parameterized by means of the closed-form model of Kosugi (1996). It is assumed that in partially saturated conditions, the air filled pore volume act as an inert solid phase, allowing the use of the Arya et al. (1999) pragmatic approach to estimate solute travel time statistics from the saturation degree and SMC parameters. The approach is evaluated using a set of partially saturated transport experiments as presented by Mohammadi and Vanclooster (2011). Experimental results showed that the mean solute travel time, μt, increases proportionally with the depth (travel distance) and decreases with flow rate. The variance of solute travel time σ2t first decreases with flow rate up to 0.4-0.6 Ks and subsequently increases. For all tested BTCs predicted solute transport with μt estimated from the conceptual model performed much better as compared to predictions with μt and σ2t estimated from calibration of solute transport at shallow soil depths. The use of μt estimated from the conceptual model therefore increases the robustness of the CLT model in predicting solute transport in heterogeneous soils at larger depths. In view of the fact that reasonable indirect estimates of the SMC can be made from basic soil properties using pedotransfer functions, the presented approach may be useful for predicting solute transport at field or watershed scales.

  12. Comparative mapping of soil physical-chemical and structural parameters at field scale to identify zones of enhanced leaching risk.

    PubMed

    Norgaard, Trine; Moldrup, Per; Olsen, Preben; Vendelboe, Anders L; Iversen, Bo V; Greve, Mogens H; Kjaer, Jeanne; de Jonge, Lis W

    2013-01-01

    Preferential flow and particle-facilitated transport through macropores contributes significantly to the transport of strongly sorbing substances such as pesticides and phosphorus. The aim of this study was to perform a field-scale characterization of basic soil physical properties like clay and organic carbon content and investigate whether it was possible to relate these to derived structural parameters such as bulk density and conservative tracer parameters and to actual particle and phosphorus leaching patterns obtained from laboratory leaching experiments. Sixty-five cylindrical soil columns of 20-cm height and 20-cm diameter and bulk soil were sampled from the topsoil in a 15-m × 15-m grid in an agricultural loamy field. Highest clay contents and highest bulk densities were found in the northern part of the field. Leaching experiments with a conservative tracer showed fast 5% tracer arrival times and high tracer recovery percentages from columns sampled from the northern part of the field, and the leached mass of particles and particulate phosphorus was also largest from this area. Strong correlations were obtained between 5% tracer arrival time, tracer recovery, and bulk density, indicating that a few well-aligned and better connected macropores might change the hydraulic conductivity between the macropores and the soil matrix, triggering an onset of preferential flow at lower rain intensities compared with less compacted soil. Overall, a comparison mapping of basic and structural characteristics including soil texture, bulk density, dissolved tracer, particle and phosphorus transport parameters identified the northern one-third of the field as a zone with higher leaching risk. This risk assessment based on parameter mapping from measurements on intact samples was in good agreement with 9 yr of pesticide detections in two horizontal wells and with particle and phosphorus leaching patterns from a distributed, shallow drainage pipe system across the field

  13. Estimating effective roughness parameters of the L-MEB model for soil moisture retrieval from SMAPVEX12 data

    NASA Astrophysics Data System (ADS)

    Martens, Brecht; Lievens, Hans; Colliander, Andreas; Jackson, Thomas; Verhoest, Niko

    2015-04-01

    Despite the continuing efforts to improve existing soil moisture retrieval algorithms, the ability to estimate soil moisture from passive microwave observations is still hampered by problems in accurately modelling the observed microwave signal. Due to the significant influence of both soil roughness and vegetation on the measured brightness temperatures, the parameterisation of these variables is of primary importance for the retrieval of the soil moisture state. Given the complex interference of surface roughness, the effect is usually accounted for using a semi-empirical model such as the one from Wang and Choudhury (1981). Together with a vegetation module, this roughness formulation is implemented in the L-band Microwave Emission from the Biosphere (L-MEB) model (Wigneron et al., 2007), which is also adopted in the operational SMOS Level 2 Soil Moisture retrieval algorithm. However, one of the main issues remains the estimation of the key roughness parameter of the Wang and Choudhury model. Several techniques exists to estimate this principal roughness parameter. Most of them try to estimate an effective roughness parameter, which is not directly linked to the physical roughness of the soil, but which can be considered optimal for the inversion of the radiative transfer model. A number of recent studies concluded that the roughness parameters could be linearly related to the observed surface soil moisture, which could be explained by a dielectric roughness, induced by the heterogeneous distribution of moisture in the soil reservoir. However, this concept has not yet been validated at large scales and/or under vegetated surfaces. This study investigated the behaviour of effective roughness parameters derived from passive remote sensing data using the L-MEB model and developed a simple model for estimating these parameters at large scale. To this end, data from the SMAP Validation Experiment 2012 (SMAPVEX12) conducted in Canada were used. Results indicate that

  14. Characterization of the Qishn sandstone reservoir, Masila Basin-Yemen, using an integrated petrophysical and seismic structural approach

    NASA Astrophysics Data System (ADS)

    Lashin, Aref; Marta, Ebrahim Bin; Khamis, Mohamed

    2016-03-01

    This study presents an integrated petrophysical and seismic structural analysis that is carried out to evaluate the reservoir properties of Qishn sandstone as well as the entrapment style of the hydrocarbons at Sharyoof field, Sayun-Masila Basin that is located at the east central of Yemen. The reservoir rocks are dominated by clean porous and permeable sandstones zones usually intercalated with some clay stone interbeds. As identified from well logs, Qishn sandstone is classified into subunits (S1A, S1B, S1C and S2) with different reservoir characteristics and hydrocarbon potentiality. A number of qualitative and quantitative well logging analyses are used to characterize the different subunits of the Qishn reservoir and identify its hydrocarbon potentiality. Dia-porosity, M-N, Pickett, Buckles plots, petrophysical analogs and lateral distribution maps are used in the analysis. Shale volume, lithology, porosity, and fluid saturation are among the most important deduced parameters. The analysis revealed that S1A and S1C are the main hydrocarbon-bearing units. More specifically, S1A unit is the best, as it attains the most prolific hydrocarbon saturations (oil saturation "SH″ up to 65) and reservoir characteristics. An average petrophysical ranges of 4-21%, 16-23%, 11-19%, 0-65%, are detected for S1A unit, regarding shale volume, total and effective porosity, and hydrocarbon saturation, respectively. Meanwhile, S1B unit exhibits less reservoir characteristics (Vsh>30%, ϕEff<15% and SH< 15%). The lateral distribution maps revealed that most of the hydrocarbons (for S1A and S1C units) are indicated at the middle of the study area as NE-SW oriented closures. The analysis and interpretation of seismic data had clarified that the structure of study area is represented by a big middle horst bounded by a group of step-like normal faults at the extreme boundaries (faulted anticlinal-structure). In conclusion, the entrapment of the encountered hydrocarbon at Sharyoof oil

  15. Effects of dry bulk density and particle size fraction on gas transport parameters in variably saturated landfill cover soil.

    PubMed

    Wickramarachchi, Praneeth; Kawamoto, Ken; Hamamoto, Shoichiro; Nagamori, Masanao; Moldrup, Per; Komatsu, Toshiko

    2011-12-01

    Landfill sites are emerging in climate change scenarios as a significant source of greenhouse gases. The compacted final soil cover at landfill sites plays a vital role for the emission, fate and transport of landfill gases. This study investigated the effects of dry bulk density, ρ(b), and particle size fraction on the main soil-gas transport parameters - soil-gas diffusivity (D(p)/D(o), ratio of gas diffusion coefficients in soil and free air) and air permeability (k(a)) - under variably-saturated moisture conditions. Soil samples were prepared by three different compaction methods (Standard and Modified Proctor compaction, and hand compaction) with resulting ρ(b) values ranging from 1.40 to 2.10 g cm(-3). Results showed that D(p) and k(a) values for the '+gravel' fraction (<35 mm) became larger than for the '-gravel' fraction (<2mm) under variably-saturated conditions for a given soil-air content (ε), likely due to enhanced gas diffusion and advection through less tortuous, large-pore networks. The effect of dry bulk density on D(p) and k(a) was most pronounced for the '+gravel' fraction. Normalized ratios were introduced for all soil-gas parameters: (i) for gas diffusivity D(p)/D(f), the ratio of measured D(p) to D(p) in total porosity (f), (ii) for air permeability k(a)/k(a)(,pF4.1), the ratio of measured k(a) to k(a) at 1235 kPa matric potential (=pF 4.1), and (iii) for soil-air content, the ratio of soil-air content (ε) to total porosity (f) (air saturation). Based on the normalized parameters, predictive power-law models for D(p)(ε/f) and k(a)(ε/f) models were developed based on a single parameter (water blockage factor M for D(p) and P for k(a)). The water blockage factors, M and P, were found to be linearly correlated to ρ(b) values, and the effects of dry bulk density on D(p) and k(a) for both '+gravel' and '-gravel' fractions were well accounted for by the new models. PMID:21813272

  16. Global SMOS Soil Moisture Retrievals from The Land Parameter Retrieval Model

    NASA Astrophysics Data System (ADS)

    Schalie, R. van der; Kerr, Y. H.; Wigneron, J. P.; Rodríguez-Fernández, N. J.; Al-Yaari, A.; Jeu, R. A. M. de

    2016-03-01

    A recent study by Van der Schalie et al. (2015) showed good results for applying the Land Parameter Retrieval Model (LPRM) on SMOS observations over southeast Australia and optimizing and evaluating the retrieved soil moisture (θ in m3 m-3) against ground measurements from the OzNet sites. In this study, the LPRM parameterization is globally updated for SMOS against modelled θ from MERRA-Land (MERRA) and ERA-Interim/Land (ERA) over the period of July 2010-December 2010, mainly focusing on two parameters: the single scattering albedo (ω) and the roughness (h). The Pearson's coefficient of correlation (r) increased rapidly when increasing the ω up to 0.12 and reached a steady state from thereon, no significant spatial pattern was found in the estimation of the single scattering albedo, which could be an artifact of the used parameter estimation procedure, and a single value of 0.12 was therefore used globally. The h was defined as a function of θ and varied slightly for the different angle bins, with maximum values of 1.1-1.3 as the angle changes from 42.5° to 57.5°.This resulted in an average r of 0.51 and 0.47, with a bias (m3 m-3) of -0.02 and -0.01 and an unbiased root mean square error (ubrmse in m3 m-3) of 0.054 and 0.056 against MERRA (ascending and descending). For ERA this resulted in an r of 0.61 and 0.53, with a bias of -0.03 and an ubrmse 0.055 and 0.059. The resulting parameterization was then used to run LPRM on SMOS observations over the period of July 2010-December 2013 and evaluated against SMOS Level 3 (L3) θ and available in situ measurements from the International Soil Moisture Network (ISMN). The comparison with L3 shows that the LPRM θ retrievals are very similar, with for the ascending set very high r of over 0.9 in large parts of the globe, with an overall average of 0.85 and the descending set performing less with an average of 0.74, mainly due to the negative r over the Sahara. The mean bias is 0.03, with an ubrmse of 0.038 and 0

  17. Parameters describing nonequilibrium transport of polycyclic aromatic hydrocarbons through contaminated soil columns: Estimability analysis, correlation, and optimization

    NASA Astrophysics Data System (ADS)

    Ngo, Viet V.; Michel, Julien; Gujisaite, Valérie; Latifi, Abderrazak; Simonnot, Marie-Odile

    2014-03-01

    The soil and groundwater at former industrial sites polluted by polycyclic aromatic hydrocarbons (PAHs) produce a very challenging environmental issue. The description of PAH transport by means of mathematical models is therefore needed for risk assessment and remediation strategies at these sites. Due to the complexity of release kinetics and transport behavior of the PAHs in the aged contaminated soils, their transport is usually evaluated at the laboratory scale. Transport parameters are then estimated from the experimental data via the inverse method. To better assess the uncertainty of optimized parameters, an estimability method was applied to firstly investigate the information content of experimental data and the possible correlations among parameters in the two-site sorption model. These works were based on the concentrations of three PAHs, Acenaphthene (ACE), Fluoranthene (FLA) and Pyrene (PYR), in the leaching solutions of the experiments under saturated and unsaturated flow conditions.

  18. Relationships among bulk soil physicochemical, biochemical, and microbiological parameters in an organic alfalfa-rice rotation system.

    PubMed

    Lopes, Ana R; Bello, Diana; Prieto-Fernández, Ángeles; Trasar-Cepeda, Carmen; Manaia, Célia M; Nunes, Olga C

    2015-08-01

    The microbial communities of bulk soil of rice paddy fields under an ancient organic agriculture regimen, consisting on an alfalfa-rice rotation system, were characterized. The drained soil of two adjacent paddies at different stages of the rotation was compared before rice seeding and after harvesting. The relationships among the soil microbial, physicochemical, and biochemical parameters were investigated using multivariate analyses. In the first year of rice cropping, aerobic cultivable heterotrophic populations correlated with lineages of presumably aerobic bacteria (e.g., Sphingobacteriales, Sphingomonadales). In the second year of rice cropping, the total C content correlated with presumable anaerobic bacteria (e.g., Anaerolineae). Independently of the year of rice cropping, before rice seeding, proteolytic activity correlated positively with the cultivable aerobic heterotrophic and ammonifier populations, the soil catabolic profile and with presumable aerobes (e.g., Sphingobacteriales, Rhizobiales) and anaerobes (e.g., Bacteroidales, Anaerolineae). After harvesting, strongest correlations were observed between cultivable diazotrophic populations and bacterial groups described as comprising N2 fixing members (e.g., Chloroflexi-Ellin6529, Betaproteobacteria, Alphaproteobacteria). It was demonstrated that chemical parameters and microbial functions were correlated with variations on the total bacterial community composition and structure occurring during rice cropping. A better understanding of these correlations and of their implications on soil productivity may be valid contributors for sustainable agriculture practices, based on ancient processes. PMID:25850741

  19. Main Parameters of Soil Quality and it's Management Under Changing Climate

    NASA Astrophysics Data System (ADS)

    László Phd, M., ,, Dr.

    2009-04-01

    Reviewing Paper Introduction: Malcolm summarised the topic of soil quality and it's management in a well synthetized form in 2000. So, the soils are fundamental to the well-being and productivity of agricultural and natural ecosystems. Soil quality is a concept being developed to characterize the usefulness and health of soils. Soil quality includes soil fertility, potential productivity, contaminant levels and their effects, resource sustainability and environmental quality. A general definition of soil quality is the degree of fitness of a soil for a specific use. The existence of multiple definitions suggests that the soil quality concept continues to evolve (Kádár, 1992; Várallyay, 1992, 1994, 2005; Németh, 1996; Malcolm, 2000; Márton, 2005; Márton et al. 2007). Recent attention has focused on the sustainability of human uses of soil, based on concerns that soil quality may be declining (Boehn and Anderson, 1997). We use sustainable to mean that a use or management of soil will sustain human well-being over time. Lal (1995) described the land resources of the world (of which soil is one component) as "finite, fragile, and nonrenewable," and reported that only about 22% (3.26 billion ha) of the total land area on the globe is suitable for cultivation and at present, only about 3% (450 million ha) has a high agricultural production capacity. Because soil is in large but finite supply, and some soil components cannot be renewed within a human time frame, the condition of soils in agriculture and the environment is an issue of global concern (Howard, 1993; FAO, 1997). Concerns include soil losses from erosion, maintaining agricultural productivity and system sustainability, protecting natural areas, and adverse effects of soil contamination on human health (Haberern, 1992; Howard, 1993; Sims et al., 1997). Parr et al. (1992) state, "...soil degradation is the single most destructive force diminishing the world's soil resource base." Soil quality guidelines

  20. Relation between soil temperature and biophysical parameters in Indian mustard seeds

    NASA Astrophysics Data System (ADS)

    Adak, T.; Chakravarty, N. V. K.

    2013-12-01

    Temporal changes in surface soil temperature were studied in winter crop. Significant changes in bare and cropped soil temperature were revealed. Air temperature showed a statistically positive and strong relationship (R2 = 0.79** to 0.92**) with the soil temperature both at morning and afternoon hours. Linear regression analysis indicated that each unit increase in ambient temperature would lead to increase in minimum and maximum soil temperatures by 1.04 and 1.02 degree, respectively. Statistically positive correlation was revealed among biophysical variables with the cumulative surface soil temperature. Linear and non-linear regression analysis indicated 62-69, 72-86 and 72-80% variation in Leaf area index, dry matter production and heat use efficiency in Indian mustard crop as a function of soil degree days. Below 60% variation in yield in Indian mustard was revealed as a function of soil temperature. In contrast, non-significant relationship between oil content and soil temperature was found, which suggests that oil accumulation in oilseed crops was not affected significantly by the soil temperature as an independent variable.

  1. Estimation of the ICBM/2 Organic Matter Simulation Model parameters for biogas digestate mineralisaion in soil using Near Infrared Data.

    NASA Astrophysics Data System (ADS)

    Cabassi, Giovanni; Cavalli, Daniele; Borrelli, Lamberto; Degano, Luigi; Marino Gallina, Pietro

    2014-05-01

    The use of simulation models to study the turnover of soil organic matter (SOM) can support experimental data interpretation and the optimization of manure management. Icbm/2 (Katter, 2001) is a SOM simulation model that describes the turnover of SOM with three pools : one for old humified SOM (CO) and two for added manure, CL ( labile "young" C) and CS (stable "young" C). C outflows from CL and CR to be humified (h) and lost as CO2-C (1-h). All pools decay with firs-order kinetics with parameter kYL, kYR and kO (fig. 1).With this model of SOM turnover, during manure decomposition into the soil, only the evolved CO2 can be easily measured. Near infrared spectroscopy has been proved to be a useful technique for soil C evaluation. Since different soil C pools are expected to have different chemical composition, it was proven that NIR can be used as a cheap technique to develop calibration models to estimate the amount of C belonging to different pools). The aim of this work was compare the calibration of ICBM/2 using C respiration data or optimal NIR prediction of CO and CL pools. A total of six laboratory treatments were established using the same soil corresponding to the application of five fertilisers and a control treatment: 1) control without N fertilisation; 2) ammonium sulphate; 3) anaerobically digested dairy cow slurry (Digested slurry); 4-5) the liquid (Liquid fraction) and solid (Solid fraction) fractions after mechanical separation of Digested slurry; and 6) anaerobically stored dairy cow slurry (Stored slurry). The "nursery" method was used with 12 sampling dates. NIR analysis were performed on the air dried grounded soils. Spectra were collected using an FT-NIR Spectrometer. Parameters calibration was done separately for each soil using the downhill simplex method. For each manure, a C partitioning factor (Fi) was optimised. In each optimization step respiration measured data or NIR estimates CL and CO were used as imput for minimisation objective

  2. Effects of dry bulk density and particle size fraction on gas transport parameters in variably saturated landfill cover soil

    SciTech Connect

    Wickramarachchi, Praneeth; Kawamoto, Ken; Hamamoto, Shoichiro; Nagamori, Masanao; Moldrup, Per; Komatsu, Toshiko

    2011-12-15

    Highlights: > The effects of soil physical properties on gas transport parameters were investigated. > Higher values of D{sub p} and k{sub a} exhibited in the '+gravel' than the '-gravel' fraction at same soil-air content ({epsilon}). > Recent power law models for D{sub p} (WLR) and k{sub a} (RPL) were modified. > Model parameters were linearly related to easily measurable dry bulk density ({rho}{sub b}). - Abstract: Landfill sites are emerging in climate change scenarios as a significant source of greenhouse gases. The compacted final soil cover at landfill sites plays a vital role for the emission, fate and transport of landfill gases. This study investigated the effects of dry bulk density, {rho}{sub b}, and particle size fraction on the main soil-gas transport parameters - soil-gas diffusivity (D{sub p}/D{sub o}, ratio of gas diffusion coefficients in soil and free air) and air permeability (k{sub a}) - under variably-saturated moisture conditions. Soil samples were prepared by three different compaction methods (Standard and Modified Proctor compaction, and hand compaction) with resulting {rho}{sub b} values ranging from 1.40 to 2.10 g cm{sup -3}. Results showed that D{sub p} and k{sub a} values for the '+gravel' fraction (<35 mm) became larger than for the '-gravel' fraction (<2 mm) under variably-saturated conditions for a given soil-air content ({epsilon}), likely due to enhanced gas diffusion and advection through less tortuous, large-pore networks. The effect of dry bulk density on D{sub p} and k{sub a} was most pronounced for the '+gravel' fraction. Normalized ratios were introduced for all soil-gas parameters: (i) for gas diffusivity D{sub p}/D{sub f}, the ratio of measured D{sub p} to D{sub p} in total porosity (f), (ii) for air permeability k{sub a}/k{sub a,pF4.1}, the ratio of measured k{sub a} to k{sub a} at 1235 kPa matric potential (=pF 4.1), and (iii) for soil-air content, the ratio of soil-air content ({epsilon}) to total porosity (f) (air

  3. On the Value of Effective Parameters Obtained Under Reduced Spatial Scale Mismatch to Represent Soil Moisture - Evapotranspiration Interactions in Land Surface Models.

    NASA Astrophysics Data System (ADS)

    Rosolem, R.; Iwema, J.; Blyth, E.; Wagener, T.; Rahman, A. S. M. M.

    2015-12-01

    Soil moisture - evapotranspiration interactions have been studied in several regions characterized by distinct soil properties, land cover types, and climate. Such interactions are usually assessed with measurements representing different spatial footprint. For example, soil moisture measurements obtained from point-scale sensors or with remote sensing products are typically compared with evapotranspiration measurements obtained with eddy covariance systems. With efforts to develop hydrometeorological models capable of simulating processes at hyper-resolution (i.e., 1 sq-km), novel approaches for intermediate-scale soil moisture measurements give us new opportunities to evaluate the representation of soil moisture and evapotranspiration processes at similar spatial scales. Here, we evaluate the performance of the Joint UK Land Environment Simulator (JULES) in which key parameters are determined effectively based on both soil moisture and evapotranspiration measurements obtained with similar horizontal footprint. We use soil moisture data from selected sites in the COsmic-ray Soil Moisture Observing System (COSMOS) network in combination with co-located Ameriflux eddy covariance towers to constrain key parameters in JULES assuming their similar horizontal footprint of hundreds of meters. The COSMOS-Ameriflux sites are characterized by distinct soils, land cover types, and climate. In addition, point-scale soil moisture at each site is also used in combination with eddy covariance measurements to constrain JULES parameters, while recognizing its much smaller support volume. Each individual site is ranked based on differences in soil moisture dynamics from both point-scale and intermediate-scale measurements. Model calibration is carried out by optimizing JULES performance against (1) point-scale soil moisture only, (2) cosmic-ray soil moisture only, (3) point-scale soil moisture and surface fluxes, and (4) cosmic-ray soil moisture and surface fluxes. We then evaluate

  4. Hydrodynamic parameters of a sandy soil determined by ground-penetrating radar inside a single ring infiltrometer

    NASA Astrophysics Data System (ADS)

    Léger, Emmanuel; Saintenoy, Albane; Coquet, Yves

    2014-07-01

    This study shows how Mualem-van Genuchten (M-vG) parameters can be obtained from GPR data acquired during water infiltration from a single ring infiltrometer in the case of a sandy soil. Water content profiles were generated at various time steps using HYDRUS-1D, based on particular values of the M-vG parameters and were converted to dielectric permittivity profiles using the Complex Refractive Index Method. The GprMax suite of programs was used to generate radargrams and to follow the wetting front progression in depth using the arrival time of the electromagnetic waves recorded by a ground-penetrating radar (GPR). Theoretically, the 1-D time convolution between reflectivity and GPR signal at any infiltration time step is related to the peak of the reflected signal recorded in the corresponding trace in the radargram. We used this relationship to invert the M-vG parameters for constant and falling head infiltrations using the Shuffled Complex Evolution (SCE-UA) algorithm. The method is presented on synthetic examples and on experiments carried out for a sandy soil. The parameters inverted are compared with values obtained in laboratory on soil samples and with disk infiltrometer measurements.

  5. H-binding groups in lignite vs. soil humic acids: NICA-Donnan and spectroscopic parameters

    SciTech Connect

    Drosos, M.; Jerzykiewicz, M.; Deligiannakis, Y.

    2009-04-15

    A comparative study has been carried out for two sets of humic acids isolated from lignites and soils. H-binding data were analyzed using the NICA-Donnan model, for three Greek lignite humic acids (HA) plus IHSS Leonardite reference HA, and five Greek soil HAs plus a commercial peat HA. {sup 13}C-CP-MAS NMR and H-binding data provide quantitative estimates for functional groups, showing that lignite HAs of diverse origin have strikingly homogeneous properties, while the H-binding structural units of soil HAs are characterized by a large degree of variability. Consistent differences between soil HA vs. lignite HA are revealed at the level of functional groups' concentrations. In the pH range 4 to 10, soil HA showed a charge variation < 3 (equiv kg{sup -1}) while lignite HAs showed a higher charge variation > 3.5 (equiv kg{sup -1}).

  6. H-binding groups in lignite vs. soil humic acids: NICA-Donnan and spectroscopic parameters.

    PubMed

    Drosos, Marios; Jerzykiewicz, Maria; Deligiannakis, Yiannis

    2009-04-01

    A comparative study has been carried out for two sets of humic acids isolated from lignites and soils. H-binding data were analyzed using the NICA-Donnan model, for three Greek lignite humic acids (HA) plus IHSS Leonardite reference HA, and five Greek soil HAs plus a commercial peat HA. (13)C-CP-MAS NMR and H-binding data provide quantitative estimates for functional groups, showing that lignite HAs of diverse origin have strikingly homogeneous properties, while the H-binding structural units of soil HAs are characterized by a large degree of variability. Consistent differences between soil HA vs. lignite HA are revealed at the level of functional groups' concentrations. In the pH range 4 to 10, soil HA showed a charge variation <3 [equiv kg(-1)] while lignite HAs showed a higher charge variation >3.5 [equiv kg(-1)]. PMID:19144349

  7. The benefits of using remotely sensed soil moisture in parameter identification of large-scale hydrological models

    NASA Astrophysics Data System (ADS)

    Wanders, Niko; Bierkens, Marc F. P.; de Jong, Steven M.; de Roo, Ad; Karssenberg, Derek

    2013-04-01

    Nowadays large-scale hydrological models are mostly calibrated using observed discharge. Although this may lead to accurate hydrograph estimation, calibration on discharge is restricted to parameters that directly affect discharge. As a result, a large part of the hydrological system that is not directly linked to discharge, in particular the unsaturated zone, remains uncalibrated, or might be modified unrealistically. Soil moisture observations from satellites have the potential to fill this gap, as these provide a direct measurement of the state of the unsaturated zone, and thus are potentially useful in calibrating unsaturated zone model parameters. This is expected to result in a better identification of the complete hydrological system, potentially leading to improved forecasts of the hydrograph as well. Here we evaluate this added value of remotely sensed soil moisture in calibration of large-scale hydrological models by addressing two research questions: 1) Does calibration on remotely sensed soil moisture lead to an improved identification of hydrological models compared to approaches that calibrate on discharge alone? 2) If this is the case, what is the improvement in the forecasted hydrograph? To answer these questions we use a dual state and parameter ensemble Kalman filter to calibrate the hydrological model LISFLOOD for the Upper-Danube area. Calibration is done with discharge and remotely sensed soil moisture from AMSR-E, SMOS and ASCAT. Estimates and spatial correlation are derived from a previous published study on the quantification of the errors and spatial error structure of microwave remote sensing techniques. Four scenarios are studied, namely, no calibration (expert knowledge), calibration on discharge, calibration on remote sensing data and calibration on both discharge and remote sensing data. Using a split-sample approach, the model is calibrated for a period of 2 years and validated using a validation period of 10 years with the calibrated

  8. Reflection seismic and petrophysical investigations over a series of major deformation zones in eastern Sweden

    NASA Astrophysics Data System (ADS)

    Malehmir, Alireza; Ahmadi, Pouya; Lundberg, Emil; Dahlin, Peter; Juhlin, Christopher; Sjöström, Håkan; Högdahl, Karin

    2013-04-01

    The Bergslagen region is one of the most ore prospective districts in south-central Sweden. We will present an overview of results from two nearly 25 km long reflection seismic profiles crossing this region in the Dannemora mining area. Seismic interpretations are constrained by ultrasonic velocity measurements on a series of rock samples, cross-dip analysis, prestack time migration, and swath 3D imaging, as well as by other available geophysical and geological observations. A series of major fault zones is imaged by the seismic data, as is a large mafic intrusion. However, the most prominent feature is a package of east-dipping reflectors found east of the Dannemora area that extend down to at least 3 km depth. This package is associated with a poly-phase, ductile-brittle deformation zone with the latest ductile movement showing east-side-up or reverse kinematics. Its total vertical displacement is estimated to be in the order of 2.5 km. In order to better understand the nature of reflectivity from the deformation zone, we extended our petrophysical studies to include Laser Doppler Interferometer (LDI) measurements, which are capable of providing information about anisotropy and potentially its system in available rock samples from the deformation zone. Up to 10% velocity-anisotropy is estimated and demonstrated to be present for the samples taken from the deformation zone. To link the lab measurements with the real seismic data, we recently processed the seismic data over the deformation zone using anisotropy parameters obtained from the LDI measurements. A partial improvement of the deformation zone image is obtained. This suggests that rock anisotropy may also contribute to generation of reflections from the deformation zones in the study area.

  9. Experimental parameters optimization of instrumental neutron activation analysis in order to determine selected elements in some industrial soils in Turkey

    NASA Astrophysics Data System (ADS)

    Haciyakupoglu, Sevilay; Nur Esen, Ayse; Erenturk, Sema

    2014-08-01

    The purpose of this study is optimization of the experimental parameters for analysis of soil matrix by instrumental neutron activation analysis and quantitative determination of barium, cerium, lanthanum, rubidium, scandium and thorium in soil samples collected from industrialized urban areas near Istanbul. Samples were irradiated in TRIGA MARK II Research Reactor of Istanbul Technical University. Two types of reference materials were used to check the accuracy of the applied method. The achieved results were found to be in compliance with certified values of the reference materials. The calculated En numbers for mentioned elements were found to be less than 1. The presented data of element concentrations in soil samples will help to trace the pollution as an impact of urbanization and industrialization, as well as providing database for future studies.

  10. Estimation of Average Shear Strength Parameters along the Slip Surface Based on the Shear Strength Diagram of Landslide Soils

    NASA Astrophysics Data System (ADS)

    Kimura, Sho; Gibo, Seiichi; Nakamura, Shinya

    The average shear strength parameters along the slip surface (c´, φ´) of the four Shimajiri-mudstone landslides having different slide patterns have been obtained by two methods involving an estimation method using the shear strength diagram of landslide soils and an ordinary method using the results of laboratory shear tests of soil samples. The deference of the two average shear strengths was small in the case of the landslides where the residual and fractured-mudstone peak strengths had been mobilized, while the two methods produced close agreement in case of the landslides where the residual and fully softened strengths had been mobilized. Although, the determination of appropriate c´, φ´ is done using the measured shear strength of slip surface soil as a fundamental rule, when it is difficult to do it due to certain restrictions, c´, φ´ can be effectively estimated using the shear strength diagram.

  11. RELATIONSHIPS BETWEEN SOME SOIL PARAMETERS AND WEED COMMUNITY (CASE STUDY: WINTER WHEAT FIELDS OF UREMIA-IRAN).

    PubMed

    Hassannejad, S; Pirouie, M Saleh; Haghi, D Zare

    2015-01-01

    In order to find relationships between weed species distribution and soil pH, calcium carbonate (CaCO₃), electrical conductivity (EC), and organic matter percentage (OM %), fields surveys were done in 50 wheats (Triticum aestivum L.) fields of Uremia county (one of the northwest counties of Iran) in 2013. Data sampling of weeds was conducted from the beginning of stem elongation until the end of heading stages of wheat. In each field, 20 quadrates (0.25 m²) were randomly placed along a "W" pattern (5 quadrates in each line of this pattern) and in each quadrat, weed species were coded and recorded (density and cover percentage) for subsequent data entry and analysis. Canonical correspondence analysis (CCA) was used to find relationships between presence and absence of weeds in wheat fields and some of soil parameters. A total 169 weed species belonging to 35 plant families were recorded. CCA showed that four soil factors including soil pH, calcium carbonate (CaCO3), electrical conductivity (EC), and organic matter percentage (OM %) showed 58.6 percentage of weed species distribution variance. Abutilon theophrasti Medicus, Datura stramonium L., Malva neglecta Wallr., Portulaca oleracea L., Sisymbrium irio L., Atriplex patulum (L.). Aellen., and Heliotropium europaeum L. had maximum correlation with soil's pH. Euphorbia peplus L. and Salvia spinosa L. had negative correlation with pH, so that increasing pH caused reduction in the presence of these weeds. The presence of Chondrilla juncea L., Lepidium perfoliatum L., and Turgenia latifolia (L.) Hoff in the center of CCA biplot indicated that these weeds were correlated with all of these soil parameters. PMID:27145592

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  13. Still searching for the Holy Grail: on the use of effective soil parameters for Parflow-CLM.

    NASA Astrophysics Data System (ADS)

    Baroni, Gabriele; Schalge, Bernd; Rihani, Jehan; Attinger, Sabine

    2015-04-01

    In the last decades the advances in computer science have led to a growing number of coupled and distributed hydrological models based on Richards' equation. Several studies were conducted for understanding hydrological processes at different spatial and temporal scales and they showed promising uses of these types of models also in practical applications. However, these models are generally applied to scales different from that at which the equation is deduced and validated. For this reason, the models are implemented with effective soil parameters that, in principle, should preserve the water fluxes that would have been estimated assuming the finer resolution scale. In this context, the reduction in spatial discretization becomes a trade-off between complexity and performance of the model. The aim of the present contribution is to assess the performance of Parflow-CLM implemented at different spatial scales. A virtual experiment based on data available for the Neckar catchment (Germany) is used as reference at 100x100m resolution. Different upscaling rules for the soil hydraulic parameters are used for coarsening the model up to 1x1km. The analysis is carried out based on different model output e.g., river discharge, evapotranspiration, soil moisture and groundwater recharge. The effects of soil variability, correlation length and spatial distribution over the water flow direction on the simulation results are discussed. Further researches aim to quantify the related uncertainty in model output and the possibility to fill in the model structure inadequacy with data assimilation techniques.

  14. EFFECTS OF THE VARIATION OF SELECT SAMPLING PARAMETERS ON SOIL VAPOR CONCENTRATIONS

    EPA Science Inventory

    Currently soil vapor surveys are commonly used as a screening technique to delineate subsurface volatile organic compound (VOC) contaminant plumes and to provide information for vapor intrusion and contaminated site evaluations. To improve our understanding of the fate and transp...

  15. Soil Parameters for Representing a Karst Geologic Terrain in the Noah Land-Surface Model over Tennessee and Kentucky

    NASA Astrophysics Data System (ADS)

    Sullivan, Z.; Fan, X.

    2015-12-01

    Currently, the Noah Land-Surface Model (Noah-LSM) coupled with the Weather Research and Forecasting (WRF) model does not have a representation of the physical behavior of a karst terrain found in a large area of Tennessee and Kentucky and 25% of land area worldwide. The soluble nature of the bedrock within a karst geologic terrains allows for the formation of caverns, joints, fissures, sinkholes, and underground streams which affect the hydrological behavior of the region. The Highland Rim of Tennessee and the Pennyroyal Plateau and Bluegrass region of Kentucky make up a larger karst area known as the Interior Low Plateau. The highly weathered upper portion of the karst terrain, known as the epikarst, allows for more rapid transport of water through the system. For this study, hydrological aspects, such as bedrock porosity and the hydraulic conductivity, were chosen within this region in order to determine the most representative subsurface parameters for the Noah-LSM. These values along with the use of similar proxy values were chosen to calculate and represent the remaining eight parameters within the SOILPARM.TBL for the WRF model. Hydraulic conductivity values show a variation ranging from around 10-7 and 10-5 ms-1 for the karst bedrock within this region. A sand and clay soil type was used along with bedrock parameters to determine an average soil parameter type for the epikarst bedrock located within this region. Results from this study show parameters for an epikarst bedrock type displaying higher water transport through the system, similar to that of a sandy soil type with a water retention similar to that of a loam type soil. The physical nature of epikarst may lead to a decrease in latent heat values over this region and increase sensible heat values. This, in turn, may effect boundary layer growth which could lead to convective development. Future modeling work can be conducted using these values by way of coupling the soil parameters with the karst

  16. Specific 137Cs-sorption capacity parameters of soils and mineral sorbents

    NASA Astrophysics Data System (ADS)

    Kruglov, S. V.; Anisimov, V. S.; Anisimova, L. N.; Aleksakhin, R. M.

    2008-06-01

    The selective sorption of cesium by some soils, minerals, and natural mineral sorbents was studied using new methodological and experimental approaches. It was found that the total capacity of two types of highly selective sorption sites significantly differing (by several orders of magnitude) in the selectivity coefficients of Cs-K ion exchange makes up 0.5-6% of the total capacity of the ion exchanger. The values of the radiocesium interception potential were determined for the studied soils and minerals.

  17. Use of airborne hyperspectral imagery to map soil parameters in tilled agricultural fields

    USGS Publications Warehouse

    Hively, W. Dean; McCarty, Gregory W.; Reeves, James B., III; Lang, Megan W.; Oesterling, Robert A.; Delwiche, Stephen R.

    2011-01-01

    Soil hyperspectral reflectance imagery was obtained for six tilled (soil) agricultural fields using an airborne imaging spectrometer (400–2450 nm, ~10 nm resolution, 2.5 m spatial resolution). Surface soil samples (n = 315) were analyzed for carbon content, particle size distribution, and 15 agronomically important elements (Mehlich-III extraction). When partial least squares (PLS) regression of imagery-derived reflectance spectra was used to predict analyte concentrations, 13 of the 19 analytes were predicted with R2 > 0.50, including carbon (0.65), aluminum (0.76), iron (0.75), and silt content (0.79). Comparison of 15 spectral math preprocessing treatments showed that a simple first derivative worked well for nearly all analytes. The resulting PLS factors were exported as a vector of coefficients and used to calculate predicted maps of soil properties for each field. Image smoothing with a 3 × 3 low-pass filter prior to spectral data extraction improved prediction accuracy. The resulting raster maps showed variation associated with topographic factors, indicating the effect of soil redistribution and moisture regime on in-field spatial variability. High-resolution maps of soil analyte concentrations can be used to improve precision environmental management of farmlands.

  18. Network analysis reveals that bacteria and fungi form modules that correlate independently with soil parameters.

    PubMed

    de Menezes, Alexandre B; Prendergast-Miller, Miranda T; Richardson, Alan E; Toscas, Peter; Farrell, Mark; Macdonald, Lynne M; Baker, Geoff; Wark, Tim; Thrall, Peter H

    2015-08-01

    Network and multivariate statistical analyses were performed to determine interactions between bacterial and fungal community terminal restriction length polymorphisms as well as soil properties in paired woodland and pasture sites. Canonical correspondence analysis (CCA) revealed that shifts in woodland community composition correlated with soil dissolved organic carbon, while changes in pasture community composition correlated with moisture, nitrogen and phosphorus. Weighted correlation network analysis detected two distinct microbial modules per land use. Bacterial and fungal ribotypes did not group separately, rather all modules comprised of both bacterial and fungal ribotypes. Woodland modules had a similar fungal : bacterial ribotype ratio, while in the pasture, one module was fungal dominated. There was no correspondence between pasture and woodland modules in their ribotype composition. The modules had different relationships to soil variables, and these contrasts were not detected without the use of network analysis. This study demonstrated that fungi and bacteria, components of the soil microbial communities usually treated as separate functional groups as in a CCA approach, were co-correlated and formed distinct associations in these adjacent habitats. Understanding these distinct modular associations may shed more light on their niche space in the soil environment, and allow a more realistic description of soil microbial ecology and function. PMID:25040229

  19. Simulation of future groundwater recharge using a climate model ensemble and SAR-image based soil parameter distributions - A case study in an intensively-used Mediterranean catchment.

    PubMed

    Herrmann, Frank; Baghdadi, Nicolas; Blaschek, Michael; Deidda, Roberto; Duttmann, Rainer; La Jeunesse, Isabelle; Sellami, Haykel; Vereecken, Harry; Wendland, Frank

    2016-02-01

    We used observed climate data, an ensemble of four GCM-RCM combinations (global and regional climate models) and the water balance model mGROWA to estimate present and future groundwater recharge for the intensively-used Thau lagoon catchment in southern France. In addition to a highly resolved soil map, soil moisture distributions obtained from SAR-images (Synthetic Aperture Radar) were used to derive the spatial distribution of soil parameters covering the full simulation domain. Doing so helped us to assess the impact of different soil parameter sources on the modelled groundwater recharge levels. Groundwater recharge was simulated in monthly time steps using the ensemble approach and analysed in its spatial and temporal variability. The soil parameters originating from both sources led to very similar groundwater recharge rates, proving that soil parameters derived from SAR images may replace traditionally used soil maps in regions where soil maps are sparse or missing. Additionally, we showed that the variance in different GCM-RCMs influences the projected magnitude of future groundwater recharge change significantly more than the variance in the soil parameter distributions derived from the two different sources. For the period between 1950 and 2100, climate change impacts based on the climate model ensemble indicated that overall groundwater recharge will possibly show a low to moderate decrease in the Thau catchment. However, as no clear trend resulted from the ensemble simulations, reliable recommendations for adapting the regional groundwater management to changed available groundwater volumes could not be derived. PMID:26190446

  20. Evaluation of soil, unsaturated, and saturated zone parameter uncertainty using GSFlow and PEST in an agricultural watershed

    NASA Astrophysics Data System (ADS)

    Zuidema, S.; Davis, J. M.

    2011-12-01

    A coupled surface-ground water hydrological model of the Burley-DeMerritt Organic Dairy Research Farm in southeastern New Hampshire is under continued development in support of a long-term mission to understand nutrient dynamics and water use in sustainable New England dairy operations. To build on previous simulations of ground water recharge and nitrogen transport, an estimate of net recharge under an array of climate scenarios is required to facilitate modeling of nutrient dynamics for the projected life span of the dairy farm. The model must therefore incorporate spatially distributed surface and soil zone processes that influence the shallow ground water system. GSFlow couples the USGS Precipitation Runoff Modeling System and MODFLOW codes and is used to simulate surface, soil, and subsurface hydrological processes using a suite of empirical and process-based algorithms and parameters. Topography of the 83 hectare model domain was derived from a 1-meter horizontal resolution LiDAR DEM with centimeter-scale accuracy. Zonation at the soil surface was derived from detailed soils mapping, aerial land cover assessment, and drainage boundaries derived from the LiDAR DEM. Meteorological forcing data are taken from nearby (5 km) NCDC and AIRMAP meteorological towers. The farm's catchment consists of regionally common land covers including pasture, forest, and forested wetland. An array of surface model structures and spatial discretizations are evaluated ranging from fine scale, incorporating areas of consistent land cover or soil types, to the catchment scale. Parameter identification and uncertainty for both PRMS and MODFLOW components is conducted using PEST software, where distributed measurements of hydraulic head, soil moisture, and streamflow are weighted by measurement uncertainty and the relative measurement abundance or redundancy to define a model to measurement misfit objective function. Model validation will be conducted against data collected in the

  1. Assessment of structural model and parameter uncertainty with a multi-model system for soil water balance models

    NASA Astrophysics Data System (ADS)

    Michalik, Thomas; Multsch, Sebastian; Frede, Hans-Georg; Breuer, Lutz

    2016-04-01

    Water for agriculture is strongly limited in arid and semi-arid regions and often of low quality in terms of salinity. The application of saline waters for irrigation increases the salt load in the rooting zone and has to be managed by leaching to maintain a healthy soil, i.e. to wash out salts by additional irrigation. Dynamic simulation models are helpful tools to calculate the root zone water fluxes and soil salinity content in order to investigate best management practices. However, there is little information on structural and parameter uncertainty for simulations regarding the water and salt balance of saline irrigation. Hence, we established a multi-model system with four different models (AquaCrop, RZWQM, SWAP, Hydrus1D/UNSATCHEM) to analyze the structural and parameter uncertainty by using the Global Likelihood and Uncertainty Estimation (GLUE) method. Hydrus1D/UNSATCHEM and SWAP were set up with multiple sets of different implemented functions (e.g. matric and osmotic stress for root water uptake) which results in a broad range of different model structures. The simulations were evaluated against soil water and salinity content observations. The posterior distribution of the GLUE analysis gives behavioral parameters sets and reveals uncertainty intervals for parameter uncertainty. Throughout all of the model sets, most parameters accounting for the soil water balance show a low uncertainty, only one or two out of five to six parameters in each model set displays a high uncertainty (e.g. pore-size distribution index in SWAP and Hydrus1D/UNSATCHEM). The differences between the models and model setups reveal the structural uncertainty. The highest structural uncertainty is observed for deep percolation fluxes between the model sets of Hydrus1D/UNSATCHEM (~200 mm) and RZWQM (~500 mm) that are more than twice as high for the latter. The model sets show a high variation in uncertainty intervals for deep percolation as well, with an interquartile range (IQR) of

  2. Identifying unsaturated soil hydraulic parameters using integrated hydrogeophysical inversion approach on time-lapse ground-penetrating radar data

    NASA Astrophysics Data System (ADS)

    Jadoon, K. Z.; Weihermüller, L.; Scharnagl, B.; Kowalsky, M. B.; Bechtold, M.; Hubbard, S. S.; Vereecken, H.; Lambot, S.

    2012-04-01

    Recently, ground-penetrating radar (GPR) has proven to have a great potential for high resolution, non-invasive mapping of the soil hydrogeophysical properties at the scale of interest. Common GPR techniques are usually based on ray-based travel time or reflection analyses to retrieve soil dielectric permittivity, which is strongly correlated to soil water content. These methods suffer, however, from two major limitations. First, only a part of the information in the GPR signal is considered (e.g., propagation time). Second, the forward model describing the radar data is subject to relatively strong simplifications with respect to electromagnetic wave propagation phenomena. These limitations typically results in errors in the reconstructed water content images and, moreover, this does not permit to exploit all information contained in the radar data. We explored an alternative method by using full-waveform hydrogeophysical inversion of time-lapse, proximal GPR data to remotely estimate the unsaturated soil hydraulic properties. The radar system is based on international standard vector network analyzer technology and a full-waveform model is used to describe wave propagation in the antenna-air-soil system, including antenna-soil interactions. A hydrodynamic model is used to constrain the inverse electromagnetic problem in reconstructing continuous vertical water content profiles. In that case the estimated parameters reduce to the soil hydraulic properties, thereby strongly reducing the dimensionality of the inverse problem. In this study, we present an application of the proposed method to a data set collected in a field experiment. The GPR model involves a full-waveform frequency-domain solution of Maxwell's equations for wave propagation in three-dimensional multilayered media. The hydrodynamic model used in this work is based on a one-dimensional solution of Richards equation and the hydrological simulator HYDRUS 1-D was used with a single- and dual

  3. Temporal dynamics of soil aggregates and microbial parameters in permanent and recently established grasslands in the temperate zone

    NASA Astrophysics Data System (ADS)

    Linsler, Deborah; Taube, Friedhelm; Geisseler, Daniel; Joergensen, Rainer Georg; Ludwig, Bernard

    2015-04-01

    While changes over time in soil aggregation or microbial parameters are well studied for arable soils, much less is known about such temporal variations in grassland soils. The objective of the present study was to determine the changes that occur within one year (between October 2010 and October 2011) for water-stable aggregate, microbial biomass carbon (Cmic) and ergosterol (as a proxy for fungal biomass) concentrations of a sandy soil under a permanent and recently established grasslands The analyzed treatments were (i) permanent grassland, (ii) grassland re-established after tillage of previous permanent grassland, and (iii) grassland established on arable land (both in September 2010). Temporal variations were found for the aggregate distribution and ergosterol concentration in the permanent grassland. For instance, the concentration of large macroaggregates (>2000 μm) in the surface soil (0-10 cm) varied strongly, with the highest concentration (mean ± standard error) in October 2011 (666 ± 12 g kg-1) and a 3.2-fold lower concentration in May 2011. An explanation could be less rainfall and decreasing soil moisture contents in May compared to October, which may have decreased the stability of this fraction. A multiple linear regression analysis showed that the large macroaggregate concentration was well described (R2=0.60) by the gravimetric moisture content, the Cmic concentration and the pH. After the tillage event in the grassland and the subsequent grassland renovation, the concentrations of large macroaggregate, Cmic and ergosterol decreased in the surface soil, while no difference was found in the soil profile (0-40 cm). In the first year after the conversion of arable land into grassland, the concentrations of Cmic and ergosterol increased by a factor of 1.4 and 3.3, respectively, in the surface soil layer, while the macroaggregate concentration was not affected. This study indicates that the aggregate dynamic in grassland is not only affected by

  4. Integrated petrophysical and lithofacies studies of lower-middle Miocene reservoirs in Belayim marine oil field, Gulf of Suez, Egypt

    NASA Astrophysics Data System (ADS)

    Ali Ali, El-Khadragy; Emad El Din Abd Elrazik, Eysa; Shebl Azam, Salah; Ahmed Hassan, Saleh

    2016-05-01

    The reservoir parameters (total gross thickness, shale volume, total porosity, effective porosity, water saturation, bulk pore volume, net pay thickness and oil in place indicator) of Kareem and Belayim formations are studied through nine wells and mapped to show the aerial distribution of these parameters. Interpretation of these maps showed that, the best locations of hydrocarbon accumulation in Belayim marine oil field are middle part, northeast and the south west directions for Kareem formation and southwest and northeast directions for Belayim formation. The petrophysical results of Belayim formation were presented in the form of 3D slicing models to exhibit the variation of these parameters in the different directions. Cross plots of Kareem formation were done using neutron, density and sonic logs which is directly influenced by the matrix composition. By using two or three porosity logs reading we determined the porosity and evaluated the matrix characteristics of Kareem formation as it is considered as a good reservoir for oil and gas and mainly composed of sand stone. Finally, facies maps for Kareem and Belayim formations which established using composite logs indicate that, the environment of deposition of Kareem formation was deep marine in the middle and northern parts and shallow in the southern parts of the study area, meanwhile in Belayim formation the environment of deposition was in lagoonal through the deposition of Baba and Feiran members and shallow to deep during the sedimentation of Sidri and Hammam Faraun members.

  5. Soil moisture affects fatty acids and oil quality parameters in peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Drought affects yield of peanut, but its effect on oleic and linoleic acids that influence its oil quality of peanut genotypes with different levels of drought resistance has not been clearly investigated. Therefore, the aims of this research were to determine whether soil water levels could affect...

  6. 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 ...

  7. Parameters affecting microwave-assisted extraction of organophosphorus pesticides from agricultural soil.

    PubMed

    Fuentes, Edwar; Báez, María E; Labra, Ronnie

    2007-10-26

    This work describes an optimised method for the determination of six representative organophosphorus pesticides (OPPs) (diazinon, parathion, methyl pirimiphos, methyl parathion, ethoprophos, and fenitrothion) in agricultural soils. The method is based on microwave-assisted extraction using a water-methanol modified mixture for desorption and simultaneous partitioning on n-hexane (MAEP), together with gas chromatography-flame photometric detection (GC-FPD). To improve GC-FPD signals (peak intensity and shape) olive oil was used effectively as a "matrix mimic". The optimisation of the extraction method was achieved in two steps: an initial approach through experimental design and principal component analysis where recovery of compounds using a water-methanol mixture ranged from 54 to 77%, and the second one by studying the addition of KH2PO4 to the extracting solution where recoveries were significantly increased, molecular replacing of OPPs from adsorption sites by phosphate being the probable extraction mechanism. Under optimised conditions, recoveries of pesticides from different soils were higher than 73%, except for methyl parathion in some soils, with SD equal or lower than 11% and detection limits ranging from 0.004 to 0.012 microg g(-1). The proposed method was used to determine OPPs in soil samples from different agricultural zones of Chile. PMID:17870081

  8. Mechanical and mineralogical modifications of petrophysical parameters by deformation bands in a hydrocarbon reservoir (Matzen, Austria)

    NASA Astrophysics Data System (ADS)

    Kaiser, Jasmin; Exner, Ulrike; Gier, Susanne; Hujer, Wolfgang

    2010-05-01

    In porous sedimentary rocks, fault zones are frequently accompanied by deformation bands. These structures are tabular zones of displacement, where grain rotation and in some cases grain fracturing result in a significant reduction in porosity. Core samples were analyzed close to large normal faults from the most productive hydrocarbon reservoir in the Vienna Basin (Austria), the Matzen oil field. The Badenian terrigeneous sandstones contain predominately quartz, feldspar and dolomite as sub-rounded, detrial grains and are weakly cemented by chlorite and kaolinite. Deformation bands occur as single bands of ca. 1-3 mm thickness and negligible displacement, as well as strands of several bands with up to 2 cm thickness and displacement of 1-2 cm. A dramatic porosity reduction can already be recognized macroscopically. In some samples, the corresponding reduction in permeability is highlighted by different degree of oil staining on either side of the bands. The mineralogical composition of the deformation bands compared to the host rock does not indicate any preferential cementation or diagenetic growth of clay minerals or calcite. Instead, clay minerals are slightly enriched in the host sediment. These observations suggest that the formation of deformation bands predates the cementation in the Matzen sands. Thus, we speculate that the porosity reduction is predominately caused by cataclastic grain size reduction. Identification of the grain scale processes of porosity and permeability reduction, in combination with the analysis of the spatial distribution and orientation of the deformation bands may provide valuable information on the reservoir properties and fluid migration paths.

  9. THE EFFECT OF P-NITROCHLOROBENZENE ON HOMEOSTASIS QUANTITATIVE PARAMETERS OF KARST CAVE CLAYS AND ECUADOR SOILS MICROBIAL COMMUNITIES.

    PubMed

    Tashyrev, O B; Suslova, O S; Rokitko, P V

    2015-01-01

    In this paper it was given the effect of p-nitrochlorobenzene (NCB) on the homeostasis quantitative parameters of cave clays microbial communities from Western Ukraine and Abkhazia (Mushkarova Yama, Kuybushevskaya) and soils of Ecuador tropical ecosystems. For these microbial communities were determined maximum permissible concentrations and types of responses on xenobiotic. Microbial communities of Mushkarova Yama cave clays and rainforest soils of Ecuador were characterized by the first type of response. Microbial communities of Kuybushevskaya clays and mountain jungles of Ecuador were characterized by the second type of response. Maximum permissible concentration of NCB for Mushkarova Yama was 200 mg/l, for the other studied microbial communities--300 mg/l. It was shown, that microbial communities were not only highly resistant to NCB but also interacted with it by destroying this xenobiotic and decreasing its concentration in 4 times. PMID:26422923

  10. Inferring Land Surface Model Parameters for the Assimilation of Satellite-Based L-Band Brightness Temperature Observations into a Soil Moisture Analysis System

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf H.; De Lannoy, Gabrielle J. M.

    2012-01-01

    The Soil Moisture and Ocean Salinity (SMOS) satellite mission provides global measurements of L-band brightness temperatures at horizontal and vertical polarization and a variety of incidence angles that are sensitive to moisture and temperature conditions in the top few centimeters of the soil. These L-band observations can therefore be assimilated into a land surface model to obtain surface and root zone soil moisture estimates. As part of the observation operator, such an assimilation system requires a radiative transfer model (RTM) that converts geophysical fields (including soil moisture and soil temperature) into modeled L-band brightness temperatures. At the global scale, the RTM parameters and the climatological soil moisture conditions are still poorly known. Using look-up tables from the literature to estimate the RTM parameters usually results in modeled L-band brightness temperatures that are strongly biased against the SMOS observations, with biases varying regionally and seasonally. Such biases must be addressed within the land data assimilation system. In this presentation, the estimation of the RTM parameters is discussed for the NASA GEOS-5 land data assimilation system, which is based on the ensemble Kalman filter (EnKF) and the Catchment land surface model. In the GEOS-5 land data assimilation system, soil moisture and brightness temperature biases are addressed in three stages. First, the global soil properties and soil hydraulic parameters that are used in the Catchment model were revised to minimize the bias in the modeled soil moisture, as verified against available in situ soil moisture measurements. Second, key parameters of the "tau-omega" RTM were calibrated prior to data assimilation using an objective function that minimizes the climatological differences between the modeled L-band brightness temperatures and the corresponding SMOS observations. Calibrated parameters include soil roughness parameters, vegetation structure parameters