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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. 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.

  10. 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.

  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. 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.

  7. 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

  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. 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.

  13. 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

  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

    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

  1. 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

  2. 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.

  3. 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.

  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. 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.

  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. 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.

  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. 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.

  9. 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

  10. 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.

  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. 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...

  13. 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...

  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. 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

  7. 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

  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. 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...

  8. 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...

  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. 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

  7. 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

  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. 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.

  11. 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

  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. 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.

  1. 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

  2. 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.

  3. 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.

  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. 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.

  9. 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

  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. 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.

  1. 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

  2. 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

  3. 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.

  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. 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.

  13. 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

  14. 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

  15. 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.

  16. 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

  17. 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

  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. 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...

  5. 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

  6. 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...

  7. 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.

  8. 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

  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. 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

  18. 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.

  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. 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

  3. 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

  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. 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 ...

  6. 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

  7. 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...

  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

  11. Microbial community composition and enzyme activities in cryoturbated arctic soils are controlled by environmental parameters rather than by soil organic matter properties

    NASA Astrophysics Data System (ADS)

    Schnecker, Jörg; Wild, Birgit; Hofhansl, Florian; Eloy Alves, Ricardo J.; Bárta, Jiří; Čapek, Petr; Fuchslueger, Lucia; Gentsch, Norman; Gittel, Antje; Guggenberger, Georg; Lashchinskiy, Nikolay; Mikutta, Robert; Šantrůčková, Hana; Shibistova, Olga; Knoltsch, Anna; Takriti, Mounir; Urich, Tim; Richter, Andreas

    2014-05-01

    Enzyme-mediated decomposition of soil organic matter (SOM) is controlled by environmental parameters (i.e. temperature, moisture, pH) and organic matter properties. The role of these factors as well as the role of microbial community composition and therefore the main drivers of enzymatic decomposition of SOM are largely unknown, since all of these factors are often intercorrelated. We investigated soils from three regions in the Siberian Arctic, where carbon rich topsoil material has been incorporated into the subsoil (cryoturbation). We took advantage of this combination of topsoil organic matter and subsoil environmental conditions, to identify controls on microbial community composition and enzyme activities. We found that microbial community composition (estimated by phospholipid fatty acids analysis), was similar in cryoturbated OM and in surrounding subsoil, although C and N content were similar in cryoturbated material and topsoils. These results suggest that physical conditions rather than SOM properties shaped microbial community composition. To identify direct and indirect drivers of extracellular enzyme activities (cellobiohydrolase, leucine-amino-peptidase and phenoloxidase) we included microbial community composition, C, N and clay content, as well as pH in structural equation models. Models for regular horizons (excluding cryoturbated material), showed that enzyme activities were mainly controlled by C or N. Microbial community composition had no effect. In contrast models for cryoturbated OM, where the microbial community was adapted to subsoil environmental conditions, showed that enzyme activities were also related to microbial community composition. This indicates enzyme activities and more general decomposition to be limited by microbial community composition in cryoturbated organic matter, rather than by the availability of the substrates. The controlling cascade of physical parameters over microbial community composition to enzyme activities

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

    PubMed

    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. The estimability results showed that the experiment under unsaturated flow conditions contained more information content for estimating four transport parameters than under the saturated one. In addition, whatever the experimental conditions for all three PAHs the fraction of sites with instantaneous sorption, f, was highly correlated with the adsorption distribution coefficient, Kd. The very strong correlation between the two parameters f and Kd suggests that they should not be simultaneously calibrated. Transport parameters were optimized using HYDRUS-1D software with different scenarios based on the estimability analysis results. The optimization results were not always reliable, especially in the case of the experiment under saturated flow conditions because of its low information content. In addition, the estimation of transport parameters became very uncertain if two parameters f and Kd were optimized simultaneously. The findings of the current work can suggest some

  13. Three-parameter modeling of the soil sorption of acetanilide and triazine herbicide derivatives.

    PubMed

    Freitas, Mirlaine R; Matias, Stella V B G; Macedo, Renato L G; Freitas, Matheus P; Venturin, Nelson

    2014-02-01

    Herbicides have widely variable toxicity and many of them are persistent soil contaminants. Acetanilide and triazine family of herbicides have widespread use, but increasing interest for the development of new herbicides has been rising to increase their effectiveness and to diminish environmental hazard. The environmental risk of new herbicides can be accessed by estimating their soil sorption (logKoc), which is usually correlated to the octanol/water partition coefficient (logKow). However, earlier findings have shown that this correlation is not valid for some acetanilide and triazine herbicides. Thus, easily accessible quantitative structure-property relationship models are required to predict logKoc of analogues of the these compounds. Octanol/water partition coefficient, molecular weight and volume were calculated and then regressed against logKoc for two series of acetanilide and triazine herbicides using multiple linear regression, resulting in predictive and validated models. PMID:24374777

  14. Relationships between petrophysical, sedimentological and microstructural properties of the Oolithes Blanche formation, a saline aquifer in the Paris Basin.

    NASA Astrophysics Data System (ADS)

    Casteleyn, Lisa; Robion, Philippe; Collin, Pierry-Yves; Menéndez, Beatriz; David, Christian; Fernandes, Nathalie; Desaubliaux, Guy; Dreux, Rémi; Rigollet, Christophe; Badinier, Guillaume

    2010-05-01

    The Paris Basin appears to be appropriate in terms of CO2 capture and storage when considering both the amount of CO2 produced and the availability of depleted fields and deep saline aquifers. The purpose of this study is to investigate the petrophysical properties in relation with the sedimento-diagenetic environment of the "Oolithe Blanche" formation (Dogger), a deep saline aquifer considered as a potential candidate for CO2 storage. Regarding the scarcity of the core data in the Paris Basin, our investigation was firstly based on the study of field analogs in the south-east of the Paris Basin. The Oolithe Blanche Formation is composed of very shallow marine oolitic and bioclastic limestones, mainly grainstones. Three main sedimentological fabrics were defined: tide-dominated, wave-dominated (oolitic shoal) and prograding oolitic shoal fabrics. These three fabrics show subtle variations in composition (ooliths vs bioclasts) and in the distribution of the carbonate textures. The Oolithe Blanche Formation (Bathonian) is 70-80 meters thick and water salinity ranges from 1 to 4 g NaCl/l. 18 oriented blocks were collected on outcrops selected for the different sedimentological facies recognised in the formation: 9 blocks in the Bierry Lès Belles Fontaines quarry (Yonne), 5 blocks in the Ravières quarries (Côte d'Or) and 4 blocks in the Massangis quarry (Yonne). On each block, several petrophysical properties were measured on three perpendicular plugs: porosity, pore size distribution derived from mercury injection tests, permeability, capillary imbibition parameters, electrical conductivity and acoustic velocities. The sedimento-diagenetic fabric and microstructural analysis was defined by using optical microscope and scanning electron microscopy, coupled with image analysis on thin sections. The porosity measured using the water saturation triple weight method ranges from 6% to 34%. The permeability values are low, between 0.1 mD and 9 mD. The data from the

  15. Estimation of mass transport parameters of gases for quantifying CH4 oxidation in landfill soil covers.

    PubMed

    Im, J; Moon, S; Nam, K; Kim, Y-J; Kim, J Y

    2009-02-01

    Methane (CH(4)), which is one of the most abundant anthropogenic greenhouse gases, is produced from landfills. CH(4) is biologically oxidized to carbon dioxide, which has a lower global warming potential than methane, when it passes through a cover soil. In order to quantify the amount of CH(4) oxidized in a landfill cover soil, a soil column test, a diffusion cell test, and a mathematical model analysis were carried out. In the column test, maximum oxidation rates of CH(4) (V(max)) showed higher values in the upper part of the column than those in the lower part caused by the penetration of O(2) from the top. The organic matter content in the upper area was also higher due to the active microbial growth. The dispersion analysis results for O(2) and CH(4) in the column are counter-intuitive. As the upward flow rate of the landfill gas increased, the dispersion coefficient of CH(4) slightly increased, possibly due to the effect of mechanical dispersion. On the other hand, as the upward flow rate of the landfill gas increased, the dispersion coefficient of O(2) decreased. It is possible that the diffusion of gases in porous media is influenced by the counter-directional flow rate. Further analysis of other gases in the column, N(2) and CO(2), may be required to support this hypothesis, but in this paper we propose the possibility that the simulations using the diffusion coefficient of O(2) under the natural condition may overestimate the penetration of O(2) into the soil cover layer and consequently overestimate the oxidation of CH(4). PMID:18804363

  16. Extraction parameters significantly influence the quantity and the profile of PLFAs extracted from soils.

    PubMed

    Papadopoulou, Evagelia S; Karpouzas, Dimitrios G; Menkissoglu-Spiroudi, Urania

    2011-10-01

    Phospholipid fatty acid (PLFA) analysis is a robust method for characterizing soil microbial communities. We determined the effects of extraction solvent (chloroform vs dichloromethane) and buffer (phosphate vs citrate) on the yield and the profile of PLFAs extracted from an acidic (pH 5.5) and an alkaline (pH 8.6) soil following two 2-h sequential extractions. The yield and the profile of the PLFAs obtained separately by the first and the second 2-h extraction were compared to identify the impact of sequential extractions on the PLFA extraction efficiency. Chloroform-citrate and a 2 × 2-h extraction maximized PLFA yields in both soils. Multivariate analysis of the data showed that the choice of the extraction mixture did not significantly influence the profile of the PLFAs obtained by the first 2-h extraction, whereas it had a profound effect on the profile of the PLFAs obtained by the second 2-h extraction. Most PLFAs were extracted during the first extraction except 18:2ω6,9 and 22:0 which were almost equally extracted by the two sequential extractions. The choice of organic solvent significantly influenced the profile of the PLFAs extracted; their yield increased with chloroform with the exception of 18:2ω6,9 and 22:0 which were favored by dichloromethane. Overall, a 2 × 2-h extraction with chloroform/methanol/citrate is expected to provide maximum PLFA yields. PMID:21556882

  17. Changes of petrophysical properties of sandstones due to interaction with carbon dioxide, a laboratory study

    NASA Astrophysics Data System (ADS)

    Nover, Georg; von der Gönna, Jutta; Heikamp, Stephanie; Köster, Jens

    2013-04-01

    Changes of petrophysical, petrological, mineralogical, mechanical and chemical parameters were studied on sandstones from the Hessian depression and sandstones from Neidenbach (Eifel) before and after alteration with CO2. The experiments were performed in a wide pressure and temperature range (p >10<20 MPa; T > 100<200°C) to cover the pressure and temperature conditions of most promising deep saline aquifers, with the consequence that CO2 is above the critical point and thus in supercritical state (scCO2). The experiments lasted from 10 days up to more than 6 month. In repeated experiments samples were analyzed after every 2 up to 6 weeks reaction time. Experiments were performed in two different setups, i) the pore volume was fully saturated with a CO2-saturated artificial brine (3 M NaCl-solution) and ii) the pore volume was partially saturated with brine and in direct contact with wet CO2. Initial values of the untreated samples exhibit quartz to range from < 50% up to >85 weight %, density from 2.62 - 2.70 g/cm3, porosity from < 10% up to > 25% and permeability from < 10-17 up to 10-12 m². In both experimental setups porosity increased by less than 2 vol%. The increase in permeability was less than one order in magnitude for i) and more than 1.5 orders in magnitude for ii). The mineralogical composition was unchanged within the detection limit of powder X-Ray diffraction (XRD), while X-Ray Fluorescence Analysis (XRF) indicated mobilization of calcium, magnesium, aluminum and potassium. Dissolution was confirmed by the chemical analysis (ICP-OES-MS) of recovered artificial brines that showed an increase of the ionic species Ca, Mg, Al and K after the scCO2-experiments. Partial solution of feldspar and clay was detected by optical inspection and scanning electron microprobe SEM-analysis. Low frequency electrical conductivity experiments (SIP, spectral induced polarization) exhibited both, a significant increase in conductivity that could be explained by

  18. The broad-band fractal nature of heterogeneity in the upper crust from petrophysical logs

    NASA Astrophysics Data System (ADS)

    Dolan, Sean; Bean, Christopher; Riollet, Bruno

    1998-03-01

    In situ measurements of petrophysical properties of the upper crust from wire-line logs provide a direct means of assessing fluctuations in these properties with depth, and thus allow for the statistical characterization of crustal heterogeneity. Wire-line logs from a cluster of nine boreholes (1000-1500m deep) have been analysed using four different techniques: autocorrelation, semi-variogram, rescaled range and power spectra. Six of the boreholes are vertical, the remainder inclined. All penetrate clastic and pyroclastic rock. The analysis techniques have been tested on synthetic data, for which we have precise control on the scaling, in order to assess their robustness. The results, for the borehole data, show broad-band fractal scaling with a fractal dimension of 1.62 to 1.97 (autocorrelation), 1.59 to 1.79 (rescaled range) and 1.61 to 2.0 (power spectra). The use of different techniques to estimate the fractal dimension provides an excellent constraint on the results. Furthermore, it allows us to determine which model for crustal heterogeneity best describes the data: a `band-limited' von Kármán function or `unbounded' fractal scaling. In order to test the possible anisotropy in the scaling parameters, the horizontal scaling properties for this area have been calculated by correlation-spectra analysis of neighbouring wells. This suggests that upper-crustal correlation lengths are of the order of kilometres and anisotropic, being over four times greater in the horizontal direction. The origins of the observed power-law scaling are complex. Analysis of long-term correlations between logs and televiewer data points towards the influence of fracture porosity within the pyroclastics. But a fractal distribution of pore spaces within the clastics also controls the log fluctuations. Separating the logs into clastic and pyroclastic subsets reveals slight differences in fractal scaling, as determined by autocorrelation and semi-variogram. These differences are

  19. Petrophysical log interpretation of tight gas sands: Final report, 1985-1986

    SciTech Connect

    Tsay, F.S.; Fang, J.H.

    1987-06-01

    In tight-gas sands, clay minerals are detrimental to the accurate evaluation of porosity, permeability, and water saturation derived from well logs. In this study, the effects of individual clay minerals on these petrophysical properties are examined. Sixty-five samples were randomly chosen from the cored interval, 9374 to 9811 feet in depth in Amoco's Joe S. Kinsey No. 1 well of the dirgin Field in Rusk County, Texas. Samples include both shaly and sandy units of tight, delta-front sandstones of the Cotton Valley Group. Mineralogy of these samples was determined by x-ray analysis. Petrophysical properties were determined for each sample depth. The relationships between clay-mineral weight percentages and petrophysical properties were determined by analysis of simple correlation coefficients and canonical variable weights. Results show that water-sensitive clay minerals (illite and mixed-layer illite/smectite) are more effective in altering petrophysical properties derived from well-log responses than non-water-sensitive clay minerals (kaolinite and chlorite). This occurs because water-sensitive clay minerals have more bound water, larger surface areas, and higher cation exchange capacities. Porosity is affected by clay mineralogy. Log-derived porosities are increased by the presence of water associated with water-sensitive clay minerals. Bound water and water in micropores of water sensitive clay minerals increase the concentration of hydrogen ions, decrease bulk density, and increase acoustic transit time. Permeability is probably reduced preferentially by some clay minerals. However, the inaccuracy of laboratory measurements of permeability prevents these relationships from being revealed. Water saturation calculations are affected by clay minerals. Archie's water saturation is high because it does not account for the resistivity-reducing effects of water-sensitive clay minerals. 21 refs., 11 figs., 24 tabs.

  20. Effects of soil hydraulic and transport parameter uncertainty on predictions of solute transport in large lysimeters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Advanced numerical simulation models can potentially help improve guidelines for irrigation and salinity management. Many simulation model parameters have considerable uncertainty, and ideally that uncertainty should be reflected in model predictions and recommendations. In this work, we investiga...

  1. Synergy between optical and microwave remote sensing to derive soil and vegetation parameters from MAC Europe 1991 Experiment

    NASA Technical Reports Server (NTRS)

    Taconet, O.; Benallegue, M.; Vidal, A.; Vidal-Madjar, D.; Prevot, L.; Normand, M.

    1993-01-01

    The ability of remote sensing for monitoring vegetation density and soil moisture for agricultural applications is extensively studied. In optical bands, vegetation indices (NDVI, WDVI) in visible and near infrared reflectances are related to biophysical quantities as the leaf area index, the biomass. In active microwave bands, the quantitative assessment of crop parameters and soil moisture over agricultural areas by radar multiconfiguration algorithms remains prospective. Furthermore the main results are mostly validated on small test sites, but have still to be demonstrated in an operational way at a regional scale. In this study, a large data set of radar backscattering has been achieved at a regional scale on a French pilot watershed, the Orgeval, along two growing seasons in 1988 and 1989 (mainly wheat and corn). The radar backscattering was provided by the airborne scatterometer ERASME, designed at CRPE, (C and X bands and HH and VV polarizations). Empirical relationships to estimate water crop and soil moisture over wheat in CHH band under actual field conditions and at a watershed scale are investigated. Therefore, the algorithms developed in CHH band are applied for mapping the surface conditions over wheat fields using the AIRSAR and TMS images collected during the MAC EUROPE 1991 experiment. The synergy between optical and microwave bands is analyzed.

  2. Uncertainty in the determination of soil hydraulic parameters and its influence on the performance of two hydrological models of different complexity

    NASA Astrophysics Data System (ADS)

    Baroni, G.; Facchi, A.; Gandolfi, C.; Ortuani, B.; Horeschi, D.; van Dam, J. C.

    2010-02-01

    Data of soil hydraulic properties forms often a limiting factor in unsaturated zone modelling, especially at the larger scales. Investigations for the hydraulic characterization of soils are time-consuming and costly, and the accuracy of the results obtained by the different methodologies is still debated. However, we may wonder how the uncertainty in soil hydraulic parameters relates to the uncertainty of the selected modelling approach. We performed an intensive monitoring study during the cropping season of a 10 ha maize field in Northern Italy. The data were used to: i) compare different methods for determining soil hydraulic parameters and ii) evaluate the effect of the uncertainty in these parameters on different variables (i.e. evapotranspiration, average water content in the root zone, flux at the bottom boundary of the root zone) simulated by two hydrological models of different complexity: SWAP, a widely used model of soil moisture dynamics in unsaturated soils based on Richards equation, and ALHyMUS, a conceptual model of the same dynamics based on a reservoir cascade scheme. We employed five direct and indirect methods to determine soil hydraulic parameters for each horizon of the experimental profile. Two methods were based on a parameter optimization of: a) laboratory measured retention and hydraulic conductivity data and b) field measured retention and hydraulic conductivity data. The remaining three methods were based on the application of widely used Pedo-Transfer Functions: c) Rawls and Brakensiek, d) HYPRES, and e) ROSETTA. Simulations were performed using meteorological, irrigation and crop data measured at the experimental site during the period June - October 2006. Results showed a wide range of soil hydraulic parameter values generated with the different methods, especially for the saturated hydraulic conductivity Ksat and the shape parameter α of the van Genuchten curve. This is reflected in a variability of the modeling results which is

  3. Uncertainty in the determination of soil hydraulic parameters and its influence on the performance of two hydrological models of different complexity

    NASA Astrophysics Data System (ADS)

    Baroni, G.; Facchi, A.; Gandolfi, C.; Ortuani, B.; Horeschi, D.; van Dam, J. C.

    2009-06-01

    Data of soil hydraulic properties forms often a limiting factor in unsaturated zone modelling, especially at the larger scales. Investigations for the hydraulic characterization of soils are time-consuming and costly, and the accuracy of the results obtained by the different methodologies is still debated. However, we may wonder how the uncertainty in soil hydraulic parameters relates to the uncertainty of the selected modelling approach. We performed an intensive monitoring study during the cropping season of a 10 ha maize field in Northern Italy. These data were used to: i) compare different methods for determining soil hydraulic parameters and ii) evaluate the effect of the uncertainty in these parameters on different outputs (i.e. evapotranspiration, water content in the root zone, fluxes through the bottom boundary of the root zone) of two hydrological models with different complexity: SWAP, a widely used model of soil moisture dynamics in unsaturated soils based on Richards equation, and ALHyMUS, a conceptual model of the same dynamics based on a reservoir cascade scheme. We employed five direct and indirect methods to determine soil hydraulic parameters for each horizon of the experimental field. Two methods were based on a parameter optimization of: a) laboratory measured retention and hydraulic conductivity data and b) field measured retention and hydraulic conductivity data. Three methods were based on the application of widely used Pedo-Transfer Functions: c) Rawls and Brakensiek; d) HYPRES; and e) ROSETTA. Simulations were performed using meteorological, irrigation and crop data measured at the experimental site during the period June-October 2006. Results showed a wide range of soil hydraulic parameter values evaluated with the different methods, especially for the saturated hydraulic conductivity Ksat and the shape parameter α of the Van Genuchten curve. This is reflected in a variability of the modeling results which is, as expected, different for

  4. Evaluation of Noah-LSM for soil hydrology parameters in the Indian summer monsoon conditions

    NASA Astrophysics Data System (ADS)

    Patil, M. N.; Kumar, Manoj; Waghmare, R. T.; Dharmaraj, T.; Mahanty, N. C.

    2014-10-01

    The micrometeorological observations, collected over a station in Ranchi (23°45'N, 85°30'E) which is under the monsoon trough region of India, were used in the Noah-LSM (NCEP, OSU, Air Force and Office of Hydrology Land Surface Model) to investigate the model performance in wet (2009 and 2011) and dry (2010) conditions during the south-west summer monsoon season. With this analysis, it is seen that the Noah-LSM has simulated the diurnal cycle of heat fluxes (sensible and ground) reasonably. The simulated heat fluxes were compared with its direct measurements by sonic anemometer and soil heat flux plate. The net radiation and sensible heat flux are simulated well by the model, but the simulation of ground heat flux was found to be poor in both dry as well as wet conditions. The soil temperature simulations were also found to be poor in 0-5- and 5-10-cm layers compared to other deeper layers. The observations were also correlated with the Modern Era Retrospective-analysis for Research and Applications (MERRA) data. The correlation between the observations and ground heat flux was better in MERRA dataset than that of the Noah-LSM simulation.

  5. Simulating aerosols over Arabian Peninsula with CHIMERE: Sensitivity to soil, surface parameters and anthropogenic emission inventories

    NASA Astrophysics Data System (ADS)

    Beegum, S. Naseema; Gherboudj, Imen; Chaouch, Naira; Couvidat, Florian; Menut, Laurent; Ghedira, Hosni

    2016-03-01

    A three dimensional chemistry transport model, CHIMERE, was used to simulate the aerosol optical depths (AOD) over the Arabian Peninsula desert with an offline coupling of Weather Research and Forecasting (WRF) model. The simulations were undertaken with: (i) different horizontal and vertical configurations, (ii) new datasets derived for soil/surface properties, and (iii) EDGAR-HTAP anthropogenic emissions inventories. The model performance evaluations were assessed: (i) qualitatively using MODIS (Moderate-Resolution Imaging Spectroradiometer) deep blue (DB) AOD data for the two local dust events of August 6th and 23rd (2013), and (ii) quantitatively using AERONET (Aerosol Robotic Network) AOD observations, CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) aerosol extinction profiles, and AOD simulations from various forecast models. The model results were observed to be highly sensitive to erodibility and aerodynamic surface roughness length. The use of new datasets on soil erodibility, derived from the MODIS reflectance, and aerodynamic surface roughness length (z0), derived from the ERA-Interim datasets, significantly improved the simulation results. Simulations with the global EDGAR-HTAP anthropogenic emission inventories brought the simulated AOD values closer to the observations. Performance testing of the adapted model for the Arabian Peninsula domain with improved datasets showed good agreement between AERONET AOD measurements and CHIMERE simulations, where the correlation coefficient (R) is 0.6. Higher values of the correlation coefficients and slopes were observed for the dusty periods compared to the non-dusty periods.

  6. On the Pitfalls and Limitations of Applying Petrophysical Models to Geophysical Tomograms: Examples in Cross-Borehole Radar and Electrical-Resistivity Tomography

    NASA Astrophysics Data System (ADS)

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

    2004-05-01

    Geophysical field data have traditionally provided qualitative information on aquifer structure for hydrogeologic characterization; however, there is increasing interest in the application of petrophysical models to convert geophysical tomograms of electrical resistivity or radar velocity, for example, to hydrologic parameters, such as permeability, porosity, water content, and (or) salinity. Unfortunately, application of theoretical or empirical petrophysical models may be inappropriate in many situations, given the limited and variable resolution of tomographic estimates. The resolution of tomograms is a function of (1) the measurement physics, for example, electrical conduction or electromagnetic wave propagation; (2) the parameterization and regularization used for inversion; (3) measurement error; and (4) the length scale of heterogeneity. We present a framework to predict how core-scale relations between geophysical properties and hydrologic parameters break down in the inversion, which produces smoothly-varying pixel-scale estimates. Our approach upscales the core-scale relationship to the pixel-scale based on the model resolution matrix from the inversion, random field averaging, and spatial statistics of the geophysical property. In synthetic examples, we use the approach to evaluate the utility of tomograms for quantitative hydrologic estimation, in light of their resolution-dependent limitations. Comparison of examples for cross-borehole electrical resistivity tomography and radar tomography demonstrates the role of the measurement physics on the spatially-variable pixel-scale relationships between geophysical estimates and hydrologic parameters of interest. The goals of this work are to (1) raise awareness of the limitations of geophysical data, (2) provide a framework to improve survey design and assess tomograms for hydrologic estimation, and (3) promote additional research to improve the links between geophysical and hydrogeologic characterization.

  7. An integrated study of the petrophysical properties of carbonate rocks from the “Oolithe Blanche” formation in the Paris Basin

    NASA Astrophysics Data System (ADS)

    Casteleyn, Lisa; Robion, Philippe; David, Christian; Collin, Pierre-Yves; Menéndez, Beatriz; Fernandes, Nathalie; Desaubliaux, Guy; Rigollet, Christophe

    2011-04-01

    Petrophysical properties were measured on oolitic limestone from the Oolithe Blanche formation (middle Jurassic) in the Paris Basin. Eighteen oriented blocks were collected from three outcrops regarding of the three main facies, oolitic shoal facies, tide dominated facies and prograding oolitic facies. We investigated the relationship between both compressional wave and electrical conductivity with different petrophysical properties such as porosity (water porosity and mercury porosity), permeability and capillarity imbibition. These have led us to relate the variations of petrophysical properties to several microstructural parameters, among them the microporous structure is the most important. Concerning P wave velocities, the general trend observed is as expected a decrease of velocities as the porosity increases but with a significant fluctuation of velocities for a given value of porosity. We have used two distinct effective medium approximations to describe the velocity variations: the self-consistent (SC) approximation and the cemented contact theory (CCT) but no unique model can simply explain our velocity behaviours. The main parameter that controls the P wave velocities is the distribution of microporosity inside oolites: for samples with velocities higher than 4 km/s the microporosity is mainly located in the rim of the ooids while for samples with velocity lower than 4 km/s the microporosity is homogeneous across the ooids. Acoustical fabrics, which are controlled by the facies, indicate that sedimentary textural components such as the amount of cement and arrangement of elements within the oolitic limestones (bioclasts, pellets and ooids) and their degree of connectivity may have some influences on the acoustic velocities. In contrast with acoustic properties, the electrical conductivity data are not so clustered by facies indicating that transport properties are more influenced by microstructural heterogeneities. One single Archie's law can well

  8. Scaling-up parameters for site restoration process using surfactant-enhanced soil washing coupled with wastewater treatment by Fenton and Fenton-like processes.

    PubMed

    Bandala, Erick R; Cossio, Horacio; Sánchez-Lopez, Adriana D; Córdova, Felipe; Peralta-Herández, Juan M; Torres, Luis G

    2013-01-01

    Estimation of scaling-up parameters for a site restoration process using a surfactant-enhanced soil washing (SESW) process followed by the application of advanced oxidation processes (Fenton and photo-Fenton) was performed. For the SESW, different parameters were varied and the soil washing efficiency for pesticide (2,4-D) removal assessed. The resulting wastewater was treated using the Fenton reaction in the absence and presence of ultraviolet (UV) radiation for pesticide removal. Results showed that agitation speed of 1550 rpm was preferable for the best pesticide removal from contaminated soil. It was possible to wash contaminated soils with different soil concentrations; however the power drawn was higher as the soil concentration increased. Complete removal of the pesticide and the remaining surfactant was achieved using different reaction conditions. The best degradation conditions were for the photo-Fenton process using [Fe(II)] = 0.3 mM; [H2O2] = 4.0 mM where complete 2,4-D and sodium dodecylsulfate (SDS) removal was observed after 8 and 10 minutes of reaction, respectively. Further increase in the hydrogen peroxide or iron salt concentration did not show any improvement in the reaction rate. Kinetic parameters, i.e. reaction rate constant and scaling-up parameters, were determined. It was shown that, by coupling both processes (SESW and AOPs), it is possible the restoration of contaminated sites. PMID:23530350

  9. Processes, mechanisms, parameters, and modeling approaches for partially saturated flow in soil and rock media; Yucca Mountain Site Characterization Project

    SciTech Connect

    Wang, J.S.Y.; Narasimhan, T.N.

    1993-06-01

    This report discusses conceptual models and mathematical equations, analyzes distributions and correlations among hydrological parameters of soils and tuff, introduces new path integration approaches, and outlines scaling procedures to model potential-driven fluid flow in heterogeneous media. To properly model the transition from fracture-dominated flow under saturated conditions to matrix-dominated flow under partially saturated conditions, characteristic curves and permeability functions for fractures and matrix need to be improved and validated. Couplings from two-phase flow, heat transfer, solute transport, and rock deformation to liquid flow are also important. For stochastic modeling of alternating units of welded and nonwelded tuff or formations bounded by fault zones, correlations and constraints on average values of saturated permeability and air entry scaling factor between different units need to be imposed to avoid unlikely combinations of parameters and predictions. Large-scale simulations require efficient and verifiable numerical algorithms. New path integration approaches based on postulates of minimum work and mass conservation to solve flow geometry and potential distribution simultaneously are introduced. This verifiable integral approach, together with fractal scaling procedures to generate statistical realizations with parameter distribution, correlation, and scaling taken into account, can be used to quantify uncertainties and generate the cumulative distribution function for groundwater travel times.

  10. Impact of mechanical mowing and chemical treatment on phytosociological, pedochemical and biological parameters in roadside soils and vegetation.

    PubMed

    Pellegrini, Elisa; Falcone, Lino; Loppi, Stefano; Lorenzini, Giacomo; Nali, Cristina

    2016-03-01

    Many chemical and non-chemical strategies have been applied to control weeds in agricultural and industrial areas. Knowledge regarding the effects of these methods on roadside vegetation is still poor. A 2-year field experiment was performed along a road located near Livorno (Tuscany, central Italy). Eight plots/strips were identified, of which four were subjected to periodical mechanical mowing and the remaining four were treated with a chemical herbicide based on glyphosate (the producer's recommended rates were used for the selective control of broad-leaved weeds). Our results clearly showed that roadside soil and vegetation are a significant reservoir of anthropogenic activities which have a strong negative effect on several phytosociological, pedochemical and biological parameters. Compared with conventional mechanical mowing, chemical treatment induced (i) a significant increase in organic matter in the upper plot layers (+18%), and (ii) a marked reduction in weed height throughout the entire period of the experiment. Irrespectively of the kind of treatment, no significance differences were detected in terms of (i) biological quality of soil (the abundance and diversity of arthropod communities did not change), and (ii) plant elemental content (bulk concentrations of analysed trace elements had a good fit within ranges of occurrence in the "reference plant"). The glyphosate partially controlled broad-leaved weeds and this moderate efficacy is dependent upon the season/time of application. In conclusion, the rational and sustainable use of chemical herbicides may be a useful tool for the management of roadside vegetation. PMID:26573685

  11. Determining the influence of the physicochemical parameters of urban soils on As availability using chemometric methods: A preliminary study.

    PubMed

    Waterlot, Christophe; Pelfrêne, Aurélie; Douay, Francis

    2016-09-01

    An initial exploration was conducted using mathematical and statistical methods to obtain relevant information about the determination of the physicochemical parameters capable of controlling As uptake by ryegrass grown on contaminated topsoils. Concentrations of As in the soils were from 10 to 47mg/kg, mainly in the As(V) form (57%-73%). Concentrations of As in water extracts were very low (61-700μg/kg). It was suggested that As(III) was mainly in the uncharged species and As(V) in the charged species. Chemometric methods revealed that the values of the ratio As(III)/As(V) depended on the assimilated-phosphorus, the pseudo-total and water-extractable Fe contents and the soil pH. Arsenic concentrations measured in ryegrass shoots ranged from 119 to 1602μg/kg. Positive linear correlations were obtained between As in ryegrass shoots and water extractable-As. The transfer coefficient of As correlated well with the ratio assimilated-phosphorus/Fe-oxides. As(III) uptake by the shoot of ryegrass was controlled by the organic matter and Fe-oxide contents. PMID:27593285

  12. Site-specific analysis of radiological and physical parameters for cobbly soils at the Gunnison, Colorado, processing site. Revision 1

    SciTech Connect

    Not Available

    1994-01-01

    The remedial action at the Gunnison, Colorado, processing site is being performed under the Uranium Mill Tailings Radiation Control Act (UMTRCA) of 1978. Under UMTRCA, the US Environmental Protection Agency (EPA) is charged with the responsibility of developing appropriate and applicable standards for the cleanup of radiologically contaminated land and buildings at 24 designated sites, including the Gunnison, Colorado, inactive processing site. Section 108 of Public Law 95-604 states that the US Department of Energy (DOE) shall ``select and perform remedial actions at the designated processing sites and disposal sites in accordance with the general standards`` prescribed by the EPA. Regulations governing the required remedial action at inactive uranium processing sites were promulgated by the EPA in 1983 and are contained in 40 CFR Part 192 (1993), Health and Environmental Protection Standards for Uranium and Thorium Mill Tailings. This document describes the radiological and physical parameters for the remedial action of the soil.

  13. Influence of physicochemical parameters of neem (Azadirachta indica A Juss) oils on nitrification inhibition in soil.

    PubMed

    Kumar, Rajesh; Devakumar, C; Sharma, Vandana; Kakkar, Garima; Kumar, Dinesh; Panneerselvam, P

    2007-02-21

    The technology for the production of neem oil coated urea (NOCU) developed by the Indian Agricultural Research Institute is in the pipeline for adaption by several Indian fertilizer industries. Use of nitrification inhibitors is one of the methods of improving the nitrogen use efficiency (NUE) of nitrogenous fertilizers in agriculture. However, standard specifications for the neem oil as a raw material of NOCU are desired. Accordingly, the present study was undertaken to evaluate 25 samples of neem oils comprising 11 samples of expeller grade (EG) oils, 8 samples of cold-pressed (CP) oils, 3 samples of solvent-extracted oils, and 2 commercial formulations. NOCU was prepared using these oils (5000 ppm of urea-N). The soils fertilized with NOCUs (200 ppm of urea-N) were incubated at 27 degrees C and 50% water-holding capacity for a period of 15 days. Nitrapyrin (0.5% of N) coated urea served as the reference and prilled urea as control. Samples were analyzed for NH4+-N, NO2--N, and NO3--N using standard methods. The percent nitrification inhibition (NI) was calculated, and the results revealed that all of the neem oils caused NI ranging from 4.0 to 30.9%. Two samples of EG oils and two commercial formulations were found to be the best, causing 27.0-30.9% NI. Iodine, acid, and saponification values and meliacin content of all of the oils were analyzed and correlated with NI. The results revealed the direct influence of meliacin content of the neem oils on NI, which, however, was found to be negatively correlated with saponification and iodine values. There is, therefore, a need to introduce new Bureau of Indian Standards (BIS) specifications for neem oils as raw materials of NOCU. PMID:17263551

  14. Combined Borehole Seismic and Electromagnetic Inversion For High-Resolution Petrophysical Assessment Of Hydocarbon Reservoirs

    SciTech Connect

    Carlos Torres-Verdin; G. Michael Hoversten; Ki Ha Lee; Gregory Newman; Kurt Nihei

    2008-12-31

    This report summarizes the work performed between January 2005 and December 2007, under DOE research contract DE-FC26-04NT15507. The project is was performed by the Center for Petroleum and Geosystems Engineering of The University of Texas at Austin and Lawrence Berkeley National Laboratory under the auspices of the National Energy Technology Office (NETL) and the Strategic Center for Natural Gas and Oil (SCNGO). During the three-year project, we developed new methods to combine borehole sonic and electromagnetic (EM) measurements for the improved assessment of elastic and petrophysical properties of rock formations penetrated by a well. Sonic measurements consisted of full waveform acoustic amplitudes acquired with monopole and dipole sources, whereas EM measurements consisted of frequency-domain voltages acquired with multi-coil induction systems. The combination of sonic and EM measurements permitted the joint estimation of elastic and petrophysical properties in the presence of mud-filtrate invasion. It was conclusively shown that the combined interpretation of sonic and EM measurements reduced non-uniqueness in the estimation of elastic and petrophysical properties and improved the spatial resolution of the estimations compared to estimations yielded separately from the two types of measurements. Moreover, this approach enabled the assessment of dynamic petrophysical properties such as permeability, as it incorporated the physics of mud-filtrate invasion in the interpretation of the measurements. The first part of the project considered the development of fast and reliable numerical algorithms to simulate borehole sonic waveforms in 2D, 3D, and radial 1D media. Such algorithms were subsequently used in the quantitative estimation of elastic properties jointly from borehole sonic and EM measurements. In the second part of the project we developed a new algorithm to estimate water saturation, porosity, and dry-rock elastic moduli jointly from borehole sonic and

  15. INTEGRATED APPROACH FOR THE PETROPHYSICAL INTERPRETATION OF POST- AND PRE-STACK 3-D SEISMIC DATA, WELL-LOG DATA, CORE DATA, GEOLOGICAL INFORMATION AND RESERVOIR PRODUCTION DATA VIA BAYESIAN STOCHASTIC INVERSION

    SciTech Connect

    Carlos Torres-Verdin; Mrinal K. Sen

    2004-03-01

    The present report summarizes the work carried out between September 30, 2002 and August 30, 2003 under DOE research contract No. DE-FC26-00BC15305. During the third year of work for this project we focused primarily on improving the efficiency of inversion algorithms and on developing algorithms for direct estimation of petrophysical parameters. The full waveform inversion algorithm for elastic property estimation was tested rigorously on a personal computer cluster. For sixteen nodes on the cluster the parallel algorithm was found to be scalable with a near linear speedup. This enabled us to invert a 2D seismic line in less than five hours of CPU time. We were invited to write a paper on our results that was subsequently accepted for publication. We also carried out a rigorous study to examine the sensitivity and resolution of seismic data to petrophysical parameters. In other words, we developed a full waveform inversion algorithm that estimates petrophysical parameters such as porosity and saturation from pre-stack seismic waveform data. First we used a modified Biot-Gassmann equation to relate petrophysical parameters to elastic parameters. The transformation was validated with a suite of well logs acquired in the deepwater Gulf of Mexico. As a part of this study, we carried out a sensitivity analysis and found that the porosity is very well resolved while the fluid saturation remains insensitive to seismic wave amplitudes. Finally we conducted a joint inversion of pre-stack seismic waveform and production history data. To overcome the computational difficulties we used a simpler waveform modeling algorithm together with an efficient subspace approach. The algorithm was tested on a realistic synthetic data set. We observed that the use of pre-stack seismic data helps tremendously to improve horizontal resolution of porosity maps. Finally, we submitted four publications to refereed technical journals, two refereed extended abstracts to technical conferences

  16. Petrophysical characterization of first ever drilled core samples from an active CO2 storage site, the German Ketzin Pilot Site - Comparison with long term experiments

    NASA Astrophysics Data System (ADS)

    Zemke, Kornelia; Liebscher, Axel

    2014-05-01

    Petrophysical properties like porosity and permeability are key parameters for a safe long-term storage of CO2 but also for the injection operation itself. These parameters may change during and/or after the CO2 injection due to geochemical reactions in the reservoir system that are triggered by the injected CO2. Here we present petrophysical data of first ever drilled cores from a newly drilled well at the active CO2 storage site - the Ketzin pilot site in the Federal State of Brandenburg, Germany. By comparison with pre-injection baseline data from core samples recovered prior to injection, the new samples provide the unique opportunity to evaluate the impact of CO2 on pore size related properties of reservoir and cap rocks at a real injection site under in-situ reservoir conditions. After injection of 61 000 tons CO2, an additional well was drilled and new rock cores were recovered. In total 100 core samples from the reservoir and the overlaying caprock were investigated by NMR relaxation. Permeability of 20 core samples was estimated by nitrogen and porosity by helium pycnometry. The determined data are comparable between pre-injection and post-injection core samples. The lower part of the reservoir sandstone is unaffected by the injected CO2. The upper part of the reservoir sandstone shows consistently slightly lower NMR porosity and permeability values in the post-injection samples when compared to the pre-injection data. This upper sandstone part is above the fluid level and CO2 present as a free gas phase and a possible residual gas saturation of the cores distorted the NMR results. The potash-containing drilling fluid can also influence these results: NMR investigation of twin samples from inner and outer parts of the cores show a reduced fraction of larger pores for the outer core samples together with lower porosities and T2 times. The drill mud penetration depth can be controlled by the added fluorescent tracer. Due to the heterogeneous character of the

  17. Effects of diagenesis on pore texture and petrophysical properties of sandstone reservior and its geological significance

    SciTech Connect

    Zhu, G.

    1982-01-01

    This paper deals with diagenesis of Yan-10 Sandstones, Yanan Series, jurassic-the main producing horizons in an exploratory area in Shan-Gan-Ning Basin, China. The effects of diagenesis on pore texture and petrophysical porperties of sandstones, its effects on forming trapping conditions for oil pools, the genesis of low permeability zone near the oil-water boundary, as well as secondary pores together with authigenic clay minerals of sandstones are presented. Furthermore, the paper describes briefly Yan-10 Sandstones in some other areas. 11 refs.

  18. The estimation of soil parameters using observations on crop biophysical variables and the crop model STICS improve the predictions of agro environmental variables.

    NASA Astrophysics Data System (ADS)

    Varella, H.-V.

    2009-04-01

    Dynamic crop models are very useful to predict the behavior of crops in their environment and are widely used in a lot of agro-environmental work. These models have many parameters and their spatial application require a good knowledge of these parameters, especially of the soil parameters. These parameters can be estimated from soil analysis at different points but this is very costly and requires a lot of experimental work. Nevertheless, observations on crops provided by new techniques like remote sensing or yield monitoring, is a possibility for estimating soil parameters through the inversion of crop models. In this work, the STICS crop model is studied for the wheat and the sugar beet and it includes more than 200 parameters. After a previous work based on a large experimental database for calibrate parameters related to the characteristics of the crop, a global sensitivity analysis of the observed variables (leaf area index LAI and absorbed nitrogen QN provided by remote sensing data, and yield at harvest provided by yield monitoring) to the soil parameters is made, in order to determine which of them have to be estimated. This study was made in different climatic and agronomic conditions and it reveals that 7 soil parameters (4 related to the water and 3 related to the nitrogen) have a clearly influence on the variance of the observed variables and have to be therefore estimated. For estimating these 7 soil parameters, a Bayesian data assimilation method is chosen (because of available prior information on these parameters) named Importance Sampling by using observations, on wheat and sugar beet crop, of LAI and QN at various dates and yield at harvest acquired on different climatic and agronomic conditions. The quality of parameter estimation is then determined by comparing the result of parameter estimation with only prior information and the result with the posterior information provided by the Bayesian data assimilation method. The result of the

  19. Application of uniaxial confining-core clamp with hydrous pyrolysis in petrophysical and geochemical studies of source rocks at various thermal maturities

    USGS Publications Warehouse

    Lewan, Michael D.; Birdwell, Justin E.

    2013-01-01

    Understanding changes in petrophysical and geochemical parameters during source rock thermal maturation is a critical component in evaluating source-rock petroleum accumulations. Natural core data are preferred, but obtaining cores that represent the same facies of a source rock at different thermal maturities is seldom possible. An alternative approach is to induce thermal maturity changes by laboratory pyrolysis on aliquots of a source-rock sample of a given facies of interest. Hydrous pyrolysis is an effective way to induce thermal maturity on source-rock cores and provide expelled oils that are similar in composition to natural crude oils. However, net-volume increases during bitumen and oil generation result in expanded cores due to opening of bedding-plane partings. Although meaningful geochemical measurements on expanded, recovered cores are possible, the utility of the core for measuring petrophysical properties relevant to natural subsurface cores is not suitable. This problem created during hydrous pyrolysis is alleviated by using a stainless steel uniaxial confinement clamp on rock cores cut perpendicular to bedding fabric. The clamp prevents expansion just as overburden does during natural petroleum formation in the subsurface. As a result, intact cores can be recovered at various thermal maturities for the measurement of petrophysical properties as well as for geochemical analyses. This approach has been applied to 1.7-inch diameter cores taken perpendicular to the bedding fabric of a 2.3- to 2.4-inch thick slab of Mahogany oil shale from the Eocene Green River Formation. Cores were subjected to hydrous pyrolysis at 360 °C for 72 h, which represents near maximum oil generation. One core was heated unconfined and the other was heated in the uniaxial confinement clamp. The unconfined core developed open tensile fractures parallel to the bedding fabric that result in a 38 % vertical expansion of the core. These open fractures did not occur in the

  20. Absorption of artificial piggery effluent by soils: Inverse optimisation of hydraulic, solute transport, and cation exchange parameters using HP1 and UCODE

    NASA Astrophysics Data System (ADS)

    Jacques, Diederik; Smith, Chris; Simunek, Jirka; Smiles, David

    2010-05-01

    Smiles and Smith (2004) performed controlled laboratory experiments on the transport of major cations (Na, K, Mg, Ca) during water absorption in horizontal soil columns for three different times. Experimental data consists of profiles of water contents, Cl concentrations, total aqueous and sorbed concentrations of the major cations. Numerical simulation of the experimental dataset requires a coupled code that can consider variably-saturated water flow, multi-component solute transport, and geochemical reactions (aqueous complexation and cation exchange). The HP1 code, based on coupled HYDRUS-1D and PHREEQC, is used to simulate this data set. The sorption of the major cations is described as a competitive cation exchange process. The objective of the study is to calibrate hydraulic, transport, and geochemical parameters using HP1, the universal optimization code UCODE_2005 (Poeter et al., 2005), and the experimental dataset of Smiles and Smith (2004). The dataset was used to calibrate three types of parameters: soil hydraulic parameters (the parameters of the van Genuchten-Mualem model for the soil hydraulic functions), solute transport parameters (dispersivity), and geochemical parameters (exchange coefficients for the major cations and the cation exchange capacity). Different calibration runs were performed with different sets of input data, different sets of optimized parameters, and different formulations of the cation exchange process (i.e., Gapon, Rothmund-Kornfeld). Overall, the description of the dataset with the coupled code is satisfactory. Estimated parameters are within expected ranges for the type of material used. References Poeter, E.P., M.C. Hill, E.R. Banta, S. Mehl, and C. Steen, 2005. UCODE_2005 and six other computer codes for universal sensitivity analysis, calibration and uncertainty evaluation. U.S. Geological Survey Techniques and Methods 6-A11. Smiles, D.E., and C.J. Smith, 2004. Absorption of artificial piggery effluent by soil: A

  1. 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.

    2015-12-01

    Mechanical and physical properties of shales are of major importance for upper crustal fault hydro-mechanical behavior. In particular, relationships between applied stress, textural anisotropy and transport properties. These relations can be investigated in the laboratory and here, was used shales from Tournemire (southern France). Triaxial tests were performed in order to determine the elasto-plastic yield envelope on 3 sets of samples with 3various bedding orientations (0°, 45°, and 90°). For each set, experiments were carried out at increasing confining pressures (2.5, 5, 10, 20, 40, 80MPa). They were performed under nominally drained conditions, at strain rates ranging between 5x10-7 s-1 - 1x10-5 s-1up to failure. During each experiment, P and S wave elastic velocities were continuously measured, in order to monitor the evolution of elastic anisotropy. Results show that the orientation of principal stress relative to bedding plays an important role on the brittle strength. Minimum strength is observed for samples deformed at 45° to bedding. Strength anisotropy increases both with confining pressure and strain rate. We interpret this result as the cohesive strength (and fracture toughness) being strain rate dependent. Although brittle failure and stress drops were systematically observed, deformation remained aseismic. This confirms that shales are good lithological candidates for shallow aseismic creep and slow slip events. Brittle failure was preceded by the development of P wave anisotropy, due to both crack growth and mineral re-orientation. Anisotropy variations were largest for samples deformed perpendicular to bedding, at the onset of rupture. Anisotropy reversal was observed at the highest confining pressures. For samples deformed parallel to bedding, the P wave anisotropy development is weaker. For both of these orientations, Thomsens parameters were inverted from the elastic wave data in order to quantify the evolution of elastic anisotropy. We

  2. Estimation of Field-scale Aquifer Hydraulic and Sorption Parameters Based on Borehole Spectral Gamma Methods

    NASA Astrophysics Data System (ADS)

    Ward, A. L.; Draper, K.; Hasan, N.

    2010-12-01

    Knowledge of spatially variable aquifer hydraulic and sorption parameters is a pre-requisite for an improved understanding of the transport and spreading of sorbing solutes and for the development of effective strategies for remediation. Local-scale estimates of these parameters are often derived from core measurements but are typically not representative of field values. Fields-scale estimates are typically derived from pump and tracer tests but often lack the spatial resolution necessary to deconvolve the effects of fine-scale heterogeneities. Geophysical methods have the potential to bridge this gap both in terms of coverage and resolution, provided meaningful petrophysical relationships can be developed. The objective of this study was to develop a petrophysical relationship between soil textural attributes and the gamma-energy response of natural sediments. Measurements from Hanford’s 300 Area show the best model to be a linear relationship between 232Th concentration and clay content (R2 = 94%). This relationship was used to generate a 3-D distribution of clay mass fraction based on borehole spectral gamma logs. The distribution of clay was then used to predict distributions of permeability, porosity, bubbling pressure, and the pore-size distribution index, all of which are required for predicting variably saturated flow, as well as the specific surface area and cation exchange capacity needed for reactive transport predictions. With this approach, it is possible to obtain reliable estimates of hydraulic properties in zones that could not be characterized by field or laboratory measurements. The spatial distribution of flow properties is consistent with lithologic transitions inferred from geologist’s logs. A preferential flow path, identified from solute and heat tracer experiments and attributed to an erosional incision in the low-permeability Ringold Formation, is also evident. The resulting distributions can be used as a starting model for the

  3. Use of a flux-based field capacity criterion to identify effective hydraulic parameters of layered soil profiles subjected to synthetic drainage experiments

    NASA Astrophysics Data System (ADS)

    Nasta, Paolo; Romano, Nunzio

    2016-01-01

    This study explores the feasibility of identifying the effective soil hydraulic parameterization of a layered soil profile by using a conventional unsteady drainage experiment leading to field capacity. The flux-based field capacity criterion is attained by subjecting the soil profile to a synthetic drainage process implemented numerically in the Soil-Water-Atmosphere-Plant (SWAP) model. The effective hydraulic parameterization is associated to either aggregated or equivalent parameters, the former being determined by the geometrical scaling theory while the latter is obtained through the inverse modeling approach. Outcomes from both these methods depend on information that is sometimes difficult to retrieve at local scale and rather challenging or virtually impossible at larger scales. The only knowledge of topsoil hydraulic properties, for example, as retrieved by a near-surface field campaign or a data assimilation technique, is often exploited as a proxy to determine effective soil hydraulic parameterization at the largest spatial scales. Comparisons of the effective soil hydraulic characterization provided by these three methods are conducted by discussing the implications for their use and accounting for the trade-offs between required input information and model output reliability. To better highlight the epistemic errors associated to the different effective soil hydraulic properties and to provide some more practical guidance, the layered soil profiles are then grouped by using the FAO textural classes. For the moderately heterogeneous soil profiles available, all three approaches guarantee a general good predictability of the actual field capacity values and provide adequate identification of the effective hydraulic parameters. Conversely, worse performances are encountered for the highly variable vertical heterogeneity, especially when resorting to the "topsoil-only" information. In general, the best performances are guaranteed by the equivalent

  4. Parameter-induced uncertainty quantification of soil N2O, NO and CO2 emission from Höglwald spruce forest (Germany) using the LandscapeDNDC model

    NASA Astrophysics Data System (ADS)

    Rahn, K.-H.; Werner, C.; Kiese, R.; Haas, E.; Butterbach-Bahl, K.

    2012-10-01

    Assessing the uncertainties of simulation results of ecological models is becoming increasingly important, specifically if these models are used to estimate greenhouse gas emissions on site to regional/national levels. Four general sources of uncertainty effect the outcome of process-based models: (i) uncertainty of information used to initialise and drive the model, (ii) uncertainty of model parameters describing specific ecosystem processes, (iii) uncertainty of the model structure, and (iv) accurateness of measurements (e.g., soil-atmosphere greenhouse gas exchange) which are used for model testing and development. The aim of our study was to assess the simulation uncertainty of the process-based biogeochemical model LandscapeDNDC. For this we set up a Bayesian framework using a Markov Chain Monte Carlo (MCMC) method, to estimate the joint model parameter distribution. Data for model testing, parameter estimation and uncertainty assessment were taken from observations of soil fluxes of nitrous oxide (N2O), nitric oxide (NO) and carbon dioxide (CO2) as observed over a 10 yr period at the spruce site of the Höglwald Forest, Germany. By running four independent Markov Chains in parallel with identical properties (except for the parameter start values), an objective criteria for chain convergence developed by Gelman et al. (2003) could be used. Our approach shows that by means of the joint parameter distribution, we were able not only to limit the parameter space and specify the probability of parameter values, but also to assess the complex dependencies among model parameters used for simulating soil C and N trace gas emissions. This helped to improve the understanding of the behaviour of the complex LandscapeDNDC model while simulating soil C and N turnover processes and associated C and N soil-atmosphere exchange. In a final step the parameter distribution of the most sensitive parameters determining soil-atmosphere C and N exchange were used to obtain the

  5. Parameter-induced uncertainty quantification of soil N2O, NO and CO2 emission from Höglwald spruce forest (Germany) using the LandscapeDNDC model

    NASA Astrophysics Data System (ADS)

    Rahn, K.-H.; Werner, C.; Kiese, R.; Haas, E.; Butterbach-Bahl, K.

    2012-04-01

    Assessing the uncertainties of simulation results of ecological models is becoming of increasing importance, specifically if these models are used to estimate greenhouse gas emissions at site to regional/national levels. Four general sources of uncertainty effect the outcome of process-based models: (i) uncertainty of information used to initialise and drive the model, (ii) uncertainty of model parameters describing specific ecosystem processes, (iii) uncertainty of the model structure and (iv) accurateness of measurements (e.g. soil-atmosphere greenhouse gas exchange) which are used for model testing and development. The aim of our study was to assess the simulation uncertainty of the process-based biogeochemical model LandscapeDNDC. For this we set up a Bayesian framework using a Markov Chain Monte Carlo (MCMC) method, to estimate the joint model parameter distribution. Data for model testing, parameter estimation and uncertainty assessment were taken from observations of soil fluxes of nitrous oxide (N2O), nitric oxide (NO), and carbon dioxide (CO2) as observed over a 10 yr period at the spruce site of the Höglwald Forest, Germany. By running four independent Markov Chains in parallel with identical properties (except for the parameter start values), an objective criteria for chain convergence developed by Gelman et al. (2003) could be used. Our approach showed that by means of the joined parameter distribution, we were able not only to limit the parameter space and specify the probability of parameter values, but also to assess the complex dependencies among model parameters used for simulating soil C and N trace gas emissions. This helped to improve the understanding of the behaviour of the complex LandscapeDNDC model while simulating soil C and N turnover processes and associated C and N soil-atmosphere exchange. In a final step the parameter distribution of the most sensitive parameters determining soil-atmosphere C and N exchange were used to obtain the

  6. Petrophysical characterization of the Carito Norte, Mulata and Carito fields, Norte de Monagas, Eastern Venezuela

    SciTech Connect

    Porras, J.C.; De J. Valle,

    1996-08-01

    The Norte de Monagas trend is located in the Eastern Venezuelan Basin and is characterized by high temperature, high initial pressure and production rates, variable PVT properties, GORs, and asphaltene content, and the presence of a tar mat at the base of the oil column. These reservoirs were petrophysically characterized through the integration of core and log data. Productive sands are composed of very coarse- to medium-grained sands deposited primarily in deltaic to shallow marine environments. These sands are quartz-rich, with clay matrix averaging 3% in the Oligocene and 6% in the Cretaceous. The main difference is the presence of up to 30% feldspars in the Cretaceous. Clay mineralogy is dominated by illitic material in the Cretaceous and by kaolinite in the Oligocene. Post-depositional changes dominated by cementation, mechanical compaction and subsequent dissolution processes have resulted in marked improvement or degradation of the productive characteristics of these reservoirs. Rocks were divided into four petrophysical. categories based on grain size, pore throat radius, porosity and permeability. Mercury saturation vs. mercury saturation over capillary pressure plots show the dominant interconnected pore system which controls flow rates is best defined by 50% saturation. Plots constructed using R50 pore aperture correlation indicate the pore throats to be macro to mega porous. Average log calculated water saturation is 14% compared with estimated from capillary pressure data of 12% at 1200{prime} above free water level, and 15% from relative permeability data. Relative permeability data indicate the rocks behave preferably as water-wet.

  7. Borehole petrophysical chemostratigraphy of Pennsylvanian black shales in the Kansas subsurface

    USGS Publications Warehouse

    Doveton, J.H.; Merriam, D.F.

    2004-01-01

    Pennsylvanian black shales in Kansas have been studied on outcrop for decades as the core unit of the classic Midcontinent cyclothem. These shales appear to be highstand condensed sections in the sequence stratigraphic paradigm. Nuclear log suites provide several petrophysical measurements of rock chemistry that are a useful data source for chemostratigraphic studies of Pennsylvanian black shales in the subsurface. Spectral gamma-ray logs partition natural radioactivity between contributions by U, Th, and K sources. Elevated U contents in black shales can be related to reducing depositional environments, whereas the K and Th contents are indicators of clay-mineral abundance and composition. The photoelectric factor log measurement is a direct function of aggregate atomic number and so is affected by clay-mineral volume, clay-mineral iron content, and other black shale compositional elements. Neutron porosity curves are primarily a response to hydrogen content. Although good quality logs are available for many black shales, borehole washout features invalidate readings from the nuclear contact devices, whereas black shales thinner than tool resolution will be averaged with adjacent beds. Statistical analysis of nuclear log data between black shales in successive cyclothems allows systematic patterns of their chemical and petrophysical properties to be discriminated in both space and time. ?? 2004 Elsevier B.V. All rights reserved.

  8. Use of morphometric soil aggregates parameters to evaluate the reclamation process in mined areas located at amazon forest - Brazil

    NASA Astrophysics Data System (ADS)

    Ribeiro, A. I.; Fengler, F. H.; Longo, R. M.; Mello, G. F.; Damame, D. B.; Crowley, D. E.

    2015-12-01

    Brazil has a high mineral potential that have been explored over the years. A large fraction of these mineral resources are located in Amazon region, which is known for its large biodiversity and world climate importance. As the policies that control the Amazon preservation are relatively new, several mining activities have been exploring the Amazon territory, promoting a large process of degradation. Once the mining activities have a high potential of environmental changes the government created polices to restrain the mining in Amazon forests and obligate mining companies to reclaim theirs minded areas. However, the measurement of reclamation development still is a challenging task for the Professionals involved. The volume and complexity of the variables, allied to the difficulty in identifying the reclamation of ecosystem functionalities are still lack to ensure the reclamation success. In this sense this work aims to investigate the representativeness of morphometric soil aggregates parameters in the understanding of reclamation development. The study area is located in the National Forest of Jamari, State of Rondônia. In the past mining companies explored the region producing eight closed mines that are now in reclamation process. The soil aggregates morphometric measurements: geometric mean diameter (GMD), aggregate circularity index, and aggregate roundness, were choose based in its obtaining facility, and their association to biological activity. To achieve the proposed objective the aggregates of eight sites in reclamation, from different closed mines, where chosen and compared to Amazon forest and open mine soil aggregates. The results were analyzed to one way ANOVA to identifying differences between areas in reclamation, natural ecosystem, and open mine. It was obtained differences for GMD and circularity index. However, only the circularity index allowed to identifying differences between the reclamation sites. The results allowed concluding: (1

  9. Sustainability of an in situ aided phytostabilisation on highly contaminated soils using fly ashes: Effects on the vertical distribution of physicochemical parameters and trace elements.

    PubMed

    Bidar, Géraldine; Waterlot, Christophe; Verdin, Anthony; Proix, Nicolas; Courcot, Dominique; Détriché, Sébastien; Fourrier, Hervé; Richard, Antoine; Douay, Francis

    2016-04-15

    Aided phytostabilisation using trees and fly ashes is a promising technique which has shown its effectiveness in the management of highly metal-contaminated soils. However, this success is generally established based on topsoil physicochemical analysis and short-term experiments. This paper focuses on the long-term effects of the afforestation and two fly ashes (silico-aluminous and sulfo-calcic called FA1 and FA2, respectively) by assessing the integrity of fly ashes 10 years after their incorporation into the soil as well as the vertical distribution of the physicochemical parameters and trace elements (TEs) in the amended soils (F1 and F2) in comparison with a non-amended soil (R). Ten years after the soil treatment, the particle size distribution analysis between fly ashes and their corresponding masses (fly ash + soil particles) showed a loss or an agglomeration of finer particles. This evolution matches with the appearance of gypsum (CaSO4 2H2O) in FA2m instead of anhydrite (CaSO4), which is the major compound of FA2. This finding corresponds well with the dissolution and the lixiviation of Ca, S and P included in FA2 along the F2 soil profile, generating an accumulation of these elements at 30 cm depth. However, no variation of TE contamination was found between 0 and 25 cm depth in F2 soil except for Cd. Conversely, Cd, Pb, Zn and Hg enrichment was observed at 25 cm depth in the F1 soil, whereas no enrichment was observed for As. The fly ashes studied, and notably FA2, were able to reduce Cd, Pb and Zn availability in soil and this capacity persists over the time despite their structural and chemical changes. PMID:26897554

  10. 3D Seismic, Mechanical Stratigraphy, and Petrophysical Analysis of the Marcellus Shale in Taylor County, West Virginia

    NASA Astrophysics Data System (ADS)

    Weicht, Derek

    The Marcellus Shale is a Devonian age black shale formed during the Acadian Orogeny along the eastern margin of North America. The Middle Devonian Marcellus Shale is an unconventional shale-gas reservoir that has been a major target of seismic exploration and gas extraction using hydraulic fracturing and horizontal drilling. This study focuses on analyses of seismic response, mechanical, and petrophysical properties of the Marcellus Shale and surrounding strata in Taylor County, West Virginia. Spectral blueing was performed on the post stack migration seismic volume to enhance the resolution. The resolution of the volume was increased from 61 feet to 47 feet, which improved the detail observed in the seismic response and provided additional insights in the interpretation of the Marcellus and bounding intervals. The isochore map created from the modified Marcellus picks shows greater variability in the thickness of the Marcellus, with an overall trend of thickening to the east. Within the thicker part of the Marcellus, a second negative reflection event appeared that was not obvious in the post stack migration. This event was interpreted to be part of the Lower Marcellus Shale. Lambda-rho and Mu-rho parameters were calculated using compressional and shear wave vibrations and density obtained from the well logs. When combined with the Young's modulus and Poisson's ratio, these cross-plots are indicative of favorable brittle and total organic carbon (TOC) rich zones that highlight potential drilling targets in the Marcellus. TOC was estimated using the Schmoker and Passey methods, and provide very similar estimates within the Marcellus Shale. Specifically note that the Middle and Lower Marcellus are generally the more TOC rich and productive Marcellus zones.

  11. Evaluation on an original resistivity inversion method of water flooding a conglomerate reservoir based on petrophysical analysis

    NASA Astrophysics Data System (ADS)

    Liu, Renqiang; Duan, Yonggang; Tan, Fengqi; Wang, Guochang; Qin, Jianhua; Neupane, Bhupati

    2015-10-01

    An accurate inversion of original reservoir resistivity is an important problem for waterflood development in oilfields in the middle-late development period. This paper describes the theoretical model of original resistivity recovery for a conglomerate reservoir established by petrophysical models, based on the stratigraphic model of reservoir vertical invasion of the conglomerate reservoir of an oilfield. Likewise two influencing factors of the resistivity change with a water-flooded reservoir were analyzed. The first one is the clay volume decrease due to an injected water wash argillaceous particle and the reservoir resistivity changes are influenced by it, and the other is to inject water to displace crude oil in the pore space leading to the increase of the water-bearing volume. Moreover the conductive ions of the injected water and the original formation water exchange and balance because of their salinity difference, and the reservoir resistivity changes are also influenced by them. Through the analysis of the above influential factors based on the fine identification of conglomerate lithologies the inversion models of three variables, including changes in the amount of clay, the resistivity of the irreducible water and the increase of the water bearing volume, were established by core analysis data, production performance and well logging curves information, and accurately recovered the original reservoir resistivity of the conglomerate. The original oil saturation of the reservoir was calculated according to multiple linear regression models. Finally, the produced index is defined as the difference of the original oil saturation and current oil saturation to the original oil saturation ratio, and it eliminates the effects of conglomerate lithologies and heterogeneity for the quantitative evaluation of flooded layers by the use of the principle of relative value. Compared with traditional flooding sensitive parameters which are oil saturation and water

  12. Effect of seed pre-soaking with 24-epibrassinolide on growth and photosynthetic parameters of Brassica juncea L. in imidacloprid soil.

    PubMed

    Sharma, Anket; Kumar, Vinod; Singh, Ravinder; Thukral, Ashwani Kumar; Bhardwaj, Renu

    2016-11-01

    Pesticides are widely used to protect crop plants from various insect pests. However, application of pesticides causes phytotoxicity to plants which results in their impaired growth and development. Brassinosteroids are well known to protect plants under abiotic stress conditions. The purpose of the present study was to access the ameliorative role of 24-epibrassinolide (EBR) in Brassica juncea L. under imidacloprid (IMI) toxicity. B. juncea plants were raised from seeds soaked in 0.1, 1 and 100nM of EBR, and grown in soils amended with 250, 300 and 350mgkg(-1) IMI pesticide, and observed for growth, pigments and photosynthetic parameters after 30, 60 and 90 days of seed sowing. The plants grown in soil treated with IMI exhibited a significant reduction in shoot length, number of leaves, chlorophyll contents and photosynthetic parameters like photosynthetic rate, stomatal conductance, inter-cellular CO2 and transpiration rate, when compared with their respective controls. However, pigments which act as antioxidants such as carotenoids, anthocyanins and xanthophylls were increased with IMI stress. Pre-sowing seed treatment with EBR decreased the toxic effects of IMI and increased the growth, pigment biosynthesis and photosynthetic parameters of the plants grown in IMI amended soil. Maximum increase in all the growth and photosynthetic parameters was noticed in plants raised from seeds treated with 100nM EBR and grown in IMI amended soil. PMID:27454204

  13. Estimation and upscaling of dual-permeability model parameters for the transport of E.coli D21g in soils with preferential flow

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dual-permeability models are increasingly used to quantify the transport of solutes and microorganisms in soils with preferential flow. An ability to accurately determine the model parameters and their variation with preferential pathway characteristics is crucial for predicting the transport of mi...

  14. Geothermal alteration of sediments in the Salton Sea scientific drill hole: Petrophysical properties and mass changes during alteration: Final report

    SciTech Connect

    McDowell, S.D.

    1987-12-11

    This report has been divided into two sections. The first deals with the results of the petrophysical measurements, and the second concentrates on the distribution of alteration minerals and textures, and on a series of calculations of geochemical changes that occurred during alteration. 32 refs., 23 figs., 10 tabs.

  15. Field and Laboratory Measurements of H2 Uptake by Soils Designed to Yield Parameters for a Global Model

    NASA Astrophysics Data System (ADS)

    Downey, N. V.; Randerson, J. T.; Eiler, J. M.

    2005-12-01

    Soil uptake of molecular hydrogen (H2) is the dominant loss term for atmospheric H2, but the distribution and magnitude of this global sink are not well known. We combined field and laboratory experiments to estimate the sensitivity of H2 fluxes to temperature and soil moisture controls. H2 uptake by soils was measured at three sites in California for one year. Our sites included forest, desert and marsh ecosystems. Uptake rates, vertical profiles of soil H2 concentrations, soil temperature, soil moisture and CO2 fluxes were measured at each site. H2 uptake rates ranged from 0 to 23 nmol/m2/s. CO2 fluxes and H2 fluxes did not correlate at our field sites. Soil moisture was positively correlated with H2 uptake rate in the desert ecosystem. Soil samples were returned to the lab, where uptake rates as a function of temperature and soil moisture were measured with a flow through system. We observed a strong temperature dependence of uptake rate in laboratory experiments for temperatures ranging from -20 ° C to 60 ° C. H2 uptake reached a maximum at 37 ° C and persisted to temperatures below -10 ° C. Between 0 ° C and 20 ° C H2 fluxes increased by 350%. These results were used to develop a global model of the soil H2 sink.

  16. Inversion of Three Layers Multi-Scale SPM Model Based on Neural Network Technique for the Retrieval of Soil Multi-Scale Roughness and Moisture Parameters

    NASA Astrophysics Data System (ADS)

    Hosni, I.; JaafriGhamki, M.; Bennaceur Farah, L.; Naceur, M. S.

    2015-04-01

    In this paper, a multi-layered multi-scale backscattering model for a lossy medium and a neural network inversion procedure has been presented. We have used a bi-dimensional multi-scale (2D MLS) roughness description where the surface is considered as a superposition of a finite number of one-dimensional Gaussian processes each one having a spatial scale using the wavelet transform and the Mallat algorithm to describe natural surface roughness. An adapted three layers 2D MLS small perturbations (SPM) model has been used to describe radar backscattering response of semiarid sub-surfaces. The total reflection coefficients of the natural soil are computed using the multilayer model, and volumetric scattering is approximated by the internal reflections between layers. The original multi-scale SPM model includes only the surface scattering of the natural bare soil, while the multilayer soil modified 2D MLS SPM model includes both the surface scattering and the volumetric scattering within the soil. This multi-layered model has been used to calculate the total surface reflection coefficients of a natural soil surface for both horizontal and vertical co-polarizations. A parametric analysis presents the dependence of the backscattering coefficient on multi scale roughness and soil. The overall objective of this work is to retrieve soil surfaces parameters namely roughness and soil moisture related to the dielectric constant by inverting the radar backscattered signal from natural soil surfaces. To perform the inversion of the modified three layers 2D MLS SPM model, we used a multilayer neural network (NN) architecture trained by a back-propagation learning rule.

  17. Petrophysical investigation of porosity distribution in the Geneva Dolomite Member of the Grand Tower Formation in Marion County, Illinois

    NASA Astrophysics Data System (ADS)

    Summers, Barrett R.

    Porosity distribution, possible mechanisms for dolomitization and secondary porosity development in the Geneva Dolomite Member (Geneva) of the mid-Devonian Grand Tower Formation in Marion County, Illinois, are examined in this study. The Geneva has been an active petroleum reservoir for over sixty years and has recently provided new discoveries. However to date, no systematic study of these strata has been conducted using petrophysical data. Three hypotheses are tested in this investigation. The first was that qualitative porosity could be classified using a sparse petrophysical data set. The second was that porosity development, such as the presence of an inferred subaerial exposure interval, fractures, and karst could be assessed using petrophysical techniques. The third was that dolomitization mechanisms could be inferred from petrophysical methods combined with geologic history, lithologic relationships and structural geology. The petrophysical method developed requires spontaneous potential, resistivity/induction and density, neturon or sonic logs. Three methods---the F-φ-M, bulk volume water crossplot, and shallow resistivity/mud filtrate ratio---were used to evaluate porosity. Porosity type was determined by calculating the numeric average of the scores determined by each method. Porosity classifications showed good correlation to core descriptions of a well in adjacent Fayette County. In addition, porosity classifications appear to correlate well with laboratory permeability measurements from cores. Porosity classifications were mapped across Marion County at four-foot intervals. Low porosity "tight zones" and fractured strata were indicated at the upper contact of the Geneva, and appear to confirm a subaerial exposure. The causal mechanism for fracturing is believed to result from post-depositional tectonic forces. A review of published methods suggests that dolomitization of the Geneva was initiated by the Simm's model. Following a marine regression, the

  18. Shale Gas Petrophysical Models: an evaluation of contrasting approaches and assumptions

    NASA Astrophysics Data System (ADS)

    Inwood, Jennifer; Lovell, Mike; Davies, Sarah; Fishwick, Stewart; Taylor, Kevin

    2015-04-01

    Shale gas refers to fine-grained formations, or mudstones, where organic matter has matured sufficiently to produce predominantly gas, but that gas has not migrated any significant distance and hence the source rock is effectively the reservoir. Due to the success of shale gas extraction in the USA, many European countries are assessing their potential resources. A key uncertainty in evaluating the resource is the estimation of gas in place and most models are based on North American plays. However, it would seem that no single model to date can confidently predict the gas in place for a 'new' shale formation. Shale gas is frequently characterized by two distinct gas components: free gas is able to move and occupies the pores, while adsorbed gas is fixed onto organic surfaces and held in place by pressure. There are a number of different published methodologies that attempt to take account for this complicated distribution of gas within the rock ranging from models where the importance of the adsorbed gas is assumed to be negligible to those where all gas is assumed to exist within the organic pores and none within the mineral pore spaces. Models that assume both components are important and occupy adjacent volumes need to consider how to separate out the two to avoid double counting. Due to the heterogeneity of mudstones the most appropriate model may vary downhole as well as across adjacent wells. In this pilot study we consider the underlying assumptions and categorize models dependent on the deterministic or probabilistic approach used. We use an initial dataset from North America to test and compare a number of different approaches before expanding the analysis to further formations that span a range of geological and petrophysical characteristics. We then review and evaluate the models, identifying key variables and, where possible, determining their importance through sensitivity analysis. This work aims to establish guidelines for selecting the most

  19. NMR relaxation of neritic carbonates: An integrated petrophysical and petrographical approach

    NASA Astrophysics Data System (ADS)

    Vincent, Benoit; Fleury, Marc; Santerre, Yannick; Brigaud, Benjamin

    2011-05-01

    A set of carbonate outcrop samples, covering a wide range of the sedimentary textures and depositional environments existing on carbonate systems, was studied through an integrated petrographical and petrophysical approach. With the aim of improving the understanding of the NMR (Nuclear Magnetic Resonance) signal of carbonates, this work is: 1) providing an atlas for various carbonate reservoir rock-types, 2) providing a workflow for integrating geological and petrophysical data and, 3) documenting common shortfalls in NMR/MICP analyses in carbonates. The petrographical investigation includes thin section and SEM (Secondary Electron Microscope) observations, whereas petrophysical investigation includes porosity (Φ), permeability (K), NMR, MICP (Mercury Injection Capillary Pressure), and specific surface area (BET) measurements. On the basis of NMR and MICP data, 4 groups of samples were identified: (1) microporous samples, (2) micro-mesoporous samples, (3) wide multimodal samples, and (4) atypical samples. The microporous samples allow us to define a maximum NMR threshold for microporosity at a T 2 of 200 ms. NMR and MICP response of the investigated carbonates are often comparable in terms of modal distribution (microporous, micro-mesoporous and wide multimodal samples). In particular, micritization, a well known but underestimated early diagenetic process, tends to homogenize the NMR signal of primarily different sedimentary facies. A grainstone with heavily micritized grains can display well sorted unimodal NMR and MICP signatures very similar, even identical, to a mudstone-wackestone. Their signatures are comparable to that of a simple sphere packing model. On the contrary, several samples (labeled atypical samples) show a discrepancy between NMR and MICP response. This discrepancy is explained by the fact that MICP can be affected by the physical connectivity of the pore network, in case of disseminated and isolated molds in a micrite matrix for instance

  20. Petrophysical and petrographic evaluation of Sidri Member of Belayim Formation, Badri field, Gulf of Suez, Egypt

    NASA Astrophysics Data System (ADS)

    Abudeif, A. M.; Attia, M. M.; Radwan, A. E.

    2016-03-01

    Presence of sandstone streaks in Sidri Member within Belayim Formation that lies between two productive zones; Kareem Formation and Hammam Faraun Member, was the main reason to perform this study. It may represent a good hydrocarbon reservoir and will be added to the Egyptian oil production in some wells of Badri field. This Member has high resistivity signature on Electric-logs responses which attracted the attention to investigate its occurrence in the field, to delineate its distribution all-over the area, to evaluate the petrographic and petrophysical characteristics and to evaluate its productivity. Petrographic and petrophysical analyses of these sand zones were undertaken using thin section samples. The electric logs and subsurface geologic data was used to evaluate the main reservoir characteristics of the Sidri sandstone such as lithology, cementation, shale volume, porosity (Φ), effective porosity (Φ eff), estimated permeability (K), fluid saturation, fluid type and Net pay thickness. This study revealed that, Sidri sandstone facies was classified into two mainly sandy facies; blocky sandy facies which located at the northern part of the field and streaky sandy facies at the southern area of the field. These two facies are separated by shaley facies. Some wells were studied to represent the two sandy facies in Sidri Member and these sand intervals have not been tested yet. These sands consist of quartz grains with grey and pink feldspars as accessory minerals, with siliceous and calcareous cementation, with good porosity. Petrophysical evaluation of this sand unit indicated that it is hydrocarbon bearing formation in three wells and water bearing one in other wells. Electrical logs analysis (Resistivity, Density-Neutron, Sonic and Gamma-Ray) revealed that The volume of shale in this sandstone, the effective porosity, the water saturation, the estimated permeability, the hydrocarbon saturation, and the net-pay thickness are varying from 9 to 13%, 19

  1. Potential of pore water stable isotope for optimization of soil physical parameters and predicting flow and transport in the unsaturated zone

    NASA Astrophysics Data System (ADS)

    Sprenger, M.; Weiler, M.

    2013-12-01

    Determining the soil hydraulic properties is mandatory to physically model the transient water flow in the vadose zone. Inverse model approaches to optimize the parameter set have been well established within the last two decades. While the model simulations are usually fitted to soil moisture or matric potential time series, we expanded the methodology by the use of information about the isotopic compositionof the soils pore water as a sole or additional target for optimization. To demonstrate the possibilities and limits of this approach, we compared the results of inverse model approaches where the fitting targets were i) only soil moisture time series, ii) only pore water isotope concentrations, and iii) a combination of both. The analyses were conducted for three study sites with different soil properties and vegetation. One at a scots pine plantation at Hartheim, Germany with a silty topsoil and a gravelly subsoil, one at a grassland at the Kaiserstuhl, Germany with a Luvisol on loess, and another one at a beech forest within the schistous part of the Attert catchment in Luxembourg, where loamy soils of high stone content prevail. The isotopic composition of the pore water was determined with soil samples of 5 cm depth intervals resulting in δD and δ18O values as a function of depth at certain points in time. Beside these isotope profiles, also soil moisture time series at minimum three depths were available at each site. The simulation of the water flow and transport in the vadose zone was conducted with the physically based one-dimensional water flow model Hydrus 1D, where rainfall amount, its isotopic composition and the evapotranspiration served as input. The root water uptake was calculated according to the Feddes model. The transport of isotopologues was simulated with the advection-dispersion equation, while the Hydrus code was modified to allow for take-up of isotopologues during evaporation. The best parameter set of the inverse solution was found

  2. Conversion of soil color parameters from the Munsell system to the CIE-L*a*b* system

    NASA Astrophysics Data System (ADS)

    Kirillova, N. P.; Vodyanitskii, Yu. N.; Sileva, T. M.

    2015-05-01

    The Munsell optical system is unsuitable for assessing the role of pigments in the color of soils by statistical methods. Empirical approaches to the transformation of the Munsell system have been proposed only for a limited range of color tones; they do not ensure the exact calculation of correlative relationships between pigments and soil colors. A new procedure is developed for the conversion of soil colors from the Munsell system to the CIE-L*a*b* system, which does not require data interpolation. A base of converted data covering the entire range of the Munsell color system used by soil scientists is created and maintained in the tabular form using Munsell Conversion (version 4.01) software. A more significant contribution of Fe pigments to the characterization of soil color in the CIE-L*a*b* system than in the Munsell system has been substantiated with soddy-podzolic soils as an example.

  3. Joint Hydrological-Geophysical Inversion for Soil StructureIdentification

    SciTech Connect

    Finsterle, Stefan; Kowalsky, Michael B.

    2006-05-01

    Reliable prediction of subsurface flow and contaminant transport depends on the accuracy with which the values and spatial distribution of process-relevant model parameters can be identified. Successful characterization methods for complex soil systems are based on (1) an adequate parameterization of the subsurface, capable of capturing both random and structured aspects of the heterogeneous system, and (2) site-specific data that are sufficiently sensitive to the processes of interest. We present a stochastic approach where the high-resolution imaging capability of geophysical methods is combined with the process-specific information obtained from the inversion of hydrological data. Geostatistical concepts are employed as a flexible means to describe and characterize subsurface structures. The key features of the proposed approach are (1) the joint inversion of geophysical and hydrological raw data, avoiding the intermediate step of creating a (non-unique and potentially biased) tomogram of geophysical properties, (2) the concurrent estimation of hydrological and petrophysical parameters in addition to (3) the determination of geostatistical parameters from the joint inversion of hydrological and geophysical data; this approach is fundamentally different from inference of geostatistical parameters from an analysis of spatially distributed property data. The approach has been implemented into the iTOUGH2 inversion code and is demonstrated for the joint use of synthetic time-lapse ground-penetrating radar (GPR) travel times and hydrological data collected during a simulated ponded infiltration experiment at a highly heterogeneous site.

  4. Relation between magnetic parameters and nematode abundance in agricultural soils of Portugal--a multidisciplinary study in the scope of environmental magnetism.

    PubMed

    Lourenço, Ana; Esteves, Ivânia; Rocha, Armando; Abrantes, Isabel; Gomes, Celeste

    2015-04-01

    Soil is composed of different types of particles which are either natural or of anthropogenic origin. Anthropogenic particles are often related to the presence of heavy metals and thus provide information on soil quality. Magnetic parameters can detect the presence of such particles and may be used as a proxy for environmental pollution. This study explores the relationships between magnetic particles and the nematofauna of agricultural soils. Magnetic, pedological, microscopy and nematological analyses were conducted in soils collected from major regions of potato production in Portugal. The magnetic characterisation of soils identified regions with magnetic particles with possible anthropogenic origin. Microscopy analysis revealed the presence of spherical particles dominantly composed of Fe, O and C. A positive and significant relationship was found between saturation isothermal remanent magnetisation (SIRM) and mass-specific susceptibility (χ), confirming the importance the ferrimagnetic fraction to magnetic properties. The nematode communities were composed of nematodes belonging to four trophic groups (bacterial feeding, plant feeders, fungal feeders and omnivores/predators). The relationships between magnetic parameters and the nematodes showed that (1) S-25 has a linear correlation with number of nematodes per kilogram of soil and with plant feeders' trophic group and (2) SIRM correlates with the bacterial feeders trophic group. This study reveals that magnetic proxies may provide means for detecting regions with higher levels of pollution, possibly related to heavy metals. Due to the large background variability found in magnetic parameters, the sampling spacial mesh should to be further refined and the input of magnetic minerals needs to be locally calibrated. PMID:25740688

  5. Multi-targeted metagenetic analysis of the influence of climate and environmental parameters on soil microbial communities along an elevational gradient.

    PubMed

    Lanzén, Anders; Epelde, Lur; Blanco, Fernando; Martín, Iker; Artetxe, Unai; Garbisu, Carlos

    2016-01-01

    Mountain elevation gradients are invaluable sites for understanding the effects of climate change on ecosystem function, community structure and distribution. However, relatively little is known about the impact on soil microbial communities, in spite of their importance for the functioning of the soil ecosystem. Previous studies of microbial diversity along elevational gradients were often limited by confounding variables such as vegetation, pH, and nutrients. Here, we utilised a transect in the Pyrenees established to minimise variation in such parameters, to examine prokaryotic, fungal, protist and metazoan communities throughout three consecutive years. We aimed to determine the influences of climate and environmental parameters on soil microbial community structure; as well as on the relationships between those microbial communities. Further, functional diversity of heterotrophic bacteria was determined using Biolog. Prokaryotic and fungal community structure, but not alpha-diversity, correlated significantly with elevation. However, carbon-to-nitrogen ratio and pH appeared to affect prokaryotic and protist communities more strongly. Both community structure and physicochemical parameters varied considerably between years, illustrating the value of long-term monitoring of the dynamic processes controlling the soil ecosystem. Our study also illustrates both the challenges and strengths of using microbial communities as indicators of potential impacts of climate change. PMID:27321429

  6. Multi-targeted metagenetic analysis of the influence of climate and environmental parameters on soil microbial communities along an elevational gradient

    NASA Astrophysics Data System (ADS)

    Lanzén, Anders; Epelde, Lur; Blanco, Fernando; Martín, Iker; Artetxe, Unai; Garbisu, Carlos

    2016-06-01

    Mountain elevation gradients are invaluable sites for understanding the effects of climate change on ecosystem function, community structure and distribution. However, relatively little is known about the impact on soil microbial communities, in spite of their importance for the functioning of the soil ecosystem. Previous studies of microbial diversity along elevational gradients were often limited by confounding variables such as vegetation, pH, and nutrients. Here, we utilised a transect in the Pyrenees established to minimise variation in such parameters, to examine prokaryotic, fungal, protist and metazoan communities throughout three consecutive years. We aimed to determine the influences of climate and environmental parameters on soil microbial community structure; as well as on the relationships between those microbial communities. Further, functional diversity of heterotrophic bacteria was determined using Biolog. Prokaryotic and fungal community structure, but not alpha-diversity, correlated significantly with elevation. However, carbon-to-nitrogen ratio and pH appeared to affect prokaryotic and protist communities more strongly. Both community structure and physicochemical parameters varied considerably between years, illustrating the value of long-term monitoring of the dynamic processes controlling the soil ecosystem. Our study also illustrates both the challenges and strengths of using microbial communities as indicators of potential impacts of climate change.

  7. Multi-targeted metagenetic analysis of the influence of climate and environmental parameters on soil microbial communities along an elevational gradient

    PubMed Central

    Lanzén, Anders; Epelde, Lur; Blanco, Fernando; Martín, Iker; Artetxe, Unai; Garbisu, Carlos

    2016-01-01

    Mountain elevation gradients are invaluable sites for understanding the effects of climate change on ecosystem function, community structure and distribution. However, relatively little is known about the impact on soil microbial communities, in spite of their importance for the functioning of the soil ecosystem. Previous studies of microbial diversity along elevational gradients were often limited by confounding variables such as vegetation, pH, and nutrients. Here, we utilised a transect in the Pyrenees established to minimise variation in such parameters, to examine prokaryotic, fungal, protist and metazoan communities throughout three consecutive years. We aimed to determine the influences of climate and environmental parameters on soil microbial community structure; as well as on the relationships between those microbial communities. Further, functional diversity of heterotrophic bacteria was determined using Biolog. Prokaryotic and fungal community structure, but not alpha-diversity, correlated significantly with elevation. However, carbon-to-nitrogen ratio and pH appeared to affect prokaryotic and protist communities more strongly. Both community structure and physicochemical parameters varied considerably between years, illustrating the value of long-term monitoring of the dynamic processes controlling the soil ecosystem. Our study also illustrates both the challenges and strengths of using microbial communities as indicators of potential impacts of climate change. PMID:27321429

  8. Changes in fertility parameters and contents of heavy metals of soddy-podzolic soils upon the long-term application of sewage sludge

    NASA Astrophysics Data System (ADS)

    Vasbieva, M. T.; Kosolapova, A. I.

    2015-05-01

    The effect of the long-term sewage sludge (SS) application on the chemical, agrophysical, and biological properties of a soddy-podzolic soil ( Umbric Albeluvisols Abruptic) was studied. Regular SS application in the course of five crop rotations (1976-2013) ensured the improvement of the soil fertility parameters, i.e., a rise in the contents of humus, available phosphorus, and exchangeable potassium; a better state of the soil adsorption complex, bulk density, and aggregation; and higher cellulolytic, nitrification, and urease activities. The efficiencies of SS and the traditional organic fertilizer (cattle manure) were compared. The effect of the long-term application of SS on the accumulation of heavy metals in the soils was also studied. It was found that the application of SS caused a rise in the bulk content of heavy metals and in the contents of their acid-extractable and mobile forms by 1.1-6.0 times. However, the maximum permissible concentrations of heavy metals in the soils were not exceeded. In the soil subjected to the application of SS for more than 25 years, the cadmium concentration somewhat exceeded the maximum permissible concentration.

  9. The effects of environmental parameters on diffuse degassing at Stromboli volcano: Insights from joint monitoring of soil CO2 flux and radon activity

    NASA Astrophysics Data System (ADS)

    Laiolo, M.; Ranaldi, M.; Tarchini, L.; Carapezza, M. L.; Coppola, D.; Ricci, T.; Cigolini, C.

    2016-04-01

    Soil CO2 flux and 222Rn activity measurements may positively contribute to the geochemical monitoring of active volcanoes. The influence of several environmental parameters on the gas signals has been substantially demonstrated. Therefore, the implementation of tools capable of removing (or minimising) the contribution of the atmospheric effects from the acquired time series is a challenge in volcano surveillance. Here, we present 4 years-long continuous monitoring (from April 2007 to September 2011) of radon activity and soil CO2 flux collected on the NE flank of Stromboli volcano. Both gases record higher emissions during fall-winter (up to 2700 Bq * m- 3 for radon and 750 g m- 2 day- 1 for CO2) than during spring-summer seasons. Short-time variations on 222Rn activity are modulated by changes in soil humidity (rainfall), and changes in soil CO2 flux that may be ascribed to variations in wind speed and direction. The spectral analyses reveal diurnal and semi-diurnal cycles on both gases, outlining that atmospheric variations are capable to modify the gas release rate from the soil. The long-term soil CO2 flux shows a slow decreasing trend, not visible in 222Rn activity, suggesting a possible difference in the source depth of the of the gases, CO2 being deeper and likely related to degassing at depth of the magma batch involved in the February-April 2007 effusive eruption. To minimise the effect of the environmental parameters on the 222Rn concentrations and soil CO2 fluxes, two different statistical treatments were applied: the Multiple Linear Regression (MLR) and the Principal Component Regression (PCR). These approaches allow to quantify the weight of each environmental factor on the two gas species and show a strong influence of some parameters on the gas transfer processes through soils. The residual values of radon and CO2 flux, i.e. the values obtained after correction for the environmental influence, were then compared with the eruptive episodes that

  10. Effects of natural and chemical stressors on Enchytraeus albidus: can oxidative stress parameters be used as fast screening tools for the assessment of different stress impacts in soils?

    PubMed

    Howcroft, C F; Amorim, M J B; Gravato, C; Guilhermino, L; Soares, A M V M

    2009-02-01

    Enchytraeids are important organisms of the soil biocenosis. They improve the soil pore structure and the degradation of organic matter. These organisms are used in standardized testing, using survival and reproduction (6 weeks) as endpoints. The use of biomarkers, linked to ecologically relevant alterations at higher levels of biological organization, is a promising tool for Environmental Risk Assessment. Here, enchytraeids were exposed for different time periods (two days and three weeks) to different soils (OECD artificial soil, different compositions in its organic matter, clay or pH value, and LUFA 2.2 natural soil) and different chemicals (Phenmedipham and copper). The main question addressed in the present study was if the effects of chemicals and different soil properties are preceded by alterations at the sub-cellular level, and if these endpoints may be used reliantly as faster screening tools for the assessment of different stress conditions in soils. The parameters measured in E. albidus whole body were: lipid peroxidation (LPO), total glutathione (TG), as well as the enzymatic activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx) and glutathione S-transferase (GST). The results showed that biomarker responses in E. albidus were significantly affected by the soil type (GST, CAT, GPx, GR and LPO) and the duration of exposure in OECD artificial soil (GST, GPx, GR, CAT and LPO) but not in LUFA 2.2 natural soil. For the abiotic factors studied, after 2 days, low pH decreased significantly the TG levels and the activities of CAT and GR,and low OM also significantly decreased CAT and GR activities. After 3 weeks, differences in soil properties caused a decrease in GR and GPx activities, whereas increased GST activity was observed due to low organic matter and pH. Copper significantly increased the activities of CAT, GPx and GR, and decreased the activity of GST after 2 days as well as inscreasing

  11. Petrophysical zoning elements of Chertovo Koryto gold-ore deposit (Patom Upland, Eastern Siberia)

    NASA Astrophysics Data System (ADS)

    Sokolov, S. V.; Kolmakov, Y. V.; Terre, D. A.

    2015-11-01

    The paper considers magnetic susceptibility (χ) and electrode potentials (EP) of rocks in the Chertovo Koryto deposit. Carbon-bearing substance is found in all the studied samples, but in some cases, this substance supplies EP (-150 ÷ -400 mV). In these samples χ rarely exceeds 40·10-5 SI units, while, in other samples χ is 8-10 (up to 30) times higher. Less intensive EP (-20 ÷ -240 mV) is furnished due to the sulfides in this deposit. Rocks with polarized carbon-bearing substance do not contain magnetic pyrrhotine and are negative linear EP anomalies. Rocks in which carbon-bearing substance is associated with pyrrhotine are revealed as magnetic anomalies. The adjacent rocks determine petrophysical zoning of the Chertovo Koryto deposit. The combination of negative linear EP anomalies and magnetic anomalies is a potential indicator and can define the multi-stage formation of the deposit itself.

  12. Computational Challenges in the Analysis of Petrophysics Using Microtomography and Upscaling

    NASA Astrophysics Data System (ADS)

    Liu, J.; Pereira, G.; Freij-Ayoub, R.; Regenauer-Lieb, K.

    2014-12-01

    Microtomography provides detailed 3D internal structures of rocks in micro- to tens of nano-meter resolution and is quickly turning into a new technology for studying petrophysical properties of materials. An important step is the upscaling of these properties as micron or sub-micron resolution can only be done on the sample-scale of millimeters or even less than a millimeter. We present here a recently developed computational workflow for the analysis of microstructures including the upscaling of material properties. Computations of properties are first performed using conventional material science simulations at micro to nano-scale. The subsequent upscaling of these properties is done by a novel renormalization procedure based on percolation theory. We have tested the workflow using different rock samples, biological and food science materials. We have also applied the technique on high-resolution time-lapse synchrotron CT scans. In this contribution we focus on the computational challenges that arise from the big data problem of analyzing petrophysical properties and its subsequent upscaling. We discuss the following challenges: 1) Characterization of microtomography for extremely large data sets - our current capability. 2) Computational fluid dynamics simulations at pore-scale for permeability estimation - methods, computing cost and accuracy. 3) Solid mechanical computations at pore-scale for estimating elasto-plastic properties - computational stability, cost, and efficiency. 4) Extracting critical exponents from derivative models for scaling laws - models, finite element meshing, and accuracy. Significant progress in each of these challenges is necessary to transform microtomography from the current research problem into a robust computational big data tool for multi-scale scientific and engineering problems.

  13. Petrophysical and magnetic pore network anisotropy of some cretaceous sandstone from Tushka Basin, Egypt

    NASA Astrophysics Data System (ADS)

    Nabawy, Bassem S.; Rochette, Pierre; Géraud, Yves

    2009-04-01

    Pore magnetic fabric is a well-established technique for the determination of pore elongation and preferred directions for migration of the interstitial fluids. This study further exemplify this technique on a set of the Nubia sandstones through a comparison with the pore anisotropy obtained from measuring permeability in three orthogonal directions in a gaz permeameter. The Nubia sandstones are represented in Tushka area (South Egypt) by quartz arenite of large porosity (29-40 per cent) which was measured on thin sections parallel and perpendicular to the bedding plane and petrophysically by helium pycnometry and ferrofluid injection at 1 bar pressure. Petrographically, there is a detectable difference between the porosity values in the bedding plane and in the perpendicular direction indicating inhomogeneity in the pore space network distribution. The petrophysical studies indicate large porosity and permeability values with some differences between the helium and ferrofluid porosity due to presence of micro pore spaces not accessible for the ferrofluid molecules having relatively high diameters and injected at low pressure. An overall agreement is observed between the permeability anisotropy and the magnetic grain and pore fabrics (magnetic anisotropy measured before and after ferrofluid injection). The three fabrics are mainly dominated by a bedding parallel foliation. In a few cases maximum permeability appears to be perpendicular to bedding. Within the bedding plane, maximum pore elongation direction from ferrofluid injection is NNW for Adindan and Kesieba formations and NW for Abu Simbil Formation. The maximum pore elongation direction for Abu Ballas samples showed a direction fluctuating around the E-W direction, the main fault trends in Tushka area. The pore fabric of Abu Ballas formation seems therefore to be structurally controlled, while it would be originated from palaeocurrent directions in the other formations.

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    Soil erosion is one of the major concerns in sustainability of agricultural systems in different areas. Therefore there is a need to develop suitable innovative indirect methods of soil survey. One of this methods is based on well established differentiation in magnetic signature with depth in soil profile. Magnetic method can be applied in the field as well as in the laboratory on collected soil samples. The aim of this study is to evaluate suitability of magnetic method to assess soil degradation and construct maps of cumulative soil loss due to erosion at two morphologically diverse areas with different soil types. Dominant soil unit in the first locality (Brumovice) is chernozem, which is gradually degraded on slopes to regosols. In the second site (Vidim), the dominant soil unit is luvisol, gradualy transformed to regosol due to erosion. Field measurements of magnetic susceptibility were carried out on regular grid, resulting in 101 data points in Brumovice and 65 in Vidim locality. Mass specific magnetic susceptibility χ and its frequency dependence χFD was used to estimate the significance of SP ferrimagnetic particles of pedogenic origin in top soil horizons. Strong correlation was found between the volume magnetic susceptibility (field measurement) and mass- specific magnetic susceptibility measured in the laboratory (Kapicka et al 2013). Values of magnetic susceptibility are spatially distributed depending on terrain position. Higher values were measured at the flat parts (where the original topsoil horizon remained). The lowest values magnetic susceptibility were obtained on the steep valley sides. Here the original topsoil was eroded and mixed by tillage with the soil substrate (loess). Positive correlation between the organic carbon content and volume magnetic susceptibility (R2= 0.89) was found for chernozem area. The differences between the values of susceptibility in the undisturbed soil profile and the magnetic signal after uniform mixing of the

  15. The Bacterial and Fungal Diversity of an Aged PAH- and Heavy Metal-Contaminated Soil is Affected by Plant Cover and Edaphic Parameters.

    PubMed

    Bourceret, Amélia; Cébron, Aurélie; Tisserant, Emilie; Poupin, Pascal; Bauda, Pascale; Beguiristain, Thierry; Leyval, Corinne

    2016-04-01

    Industrial wasteland soils with aged PAH and heavy metal contaminations are environments where pollutant toxicity has been maintained for decades. Although the communities may be well adapted to the presence of stressors, knowledge about microbial diversity in such soils is scarce. Soil microbial community dynamics can be driven by the presence of plants, but the impact of plant development on selection or diversification of microorganisms in these soils has not been established yet. To test these hypotheses, aged-contaminated soil samples from a field trial were collected. Plots planted with alfalfa were compared to bare soil plots, and bacterial and fungal diversity and abundance were assessed after 2 and 6 years. Using pyrosequencing of 16S rRNA gene and ITS amplicons, we showed that the bacterial community was dominated by Proteobacteria, Actinobacteria, and Bacteroidetes and was characterized by low Acidobacteria abundance, while the fungal community was mainly represented by members of the Ascomycota. The short-term toxic impact of pollutants usually reduces the microbial diversity, yet in our samples bacterial and fungal species richness and diversity was high suggesting that the community structure and diversity adapted to the contaminated soil over decades. The presence of plants induced higher bacterial and fungal diversity than in bare soil. It also increased the relative abundance of bacterial members of the Actinomycetales, Rhizobiales, and Xanthomonadales orders and of most fungal orders. Multivariate analysis showed correlations between microbial community structure and heavy metal and PAH concentrations over time, but also with edaphic parameters (C/N, pH, phosphorus, and nitrogen concentrations). PMID:26440298

  16. Long-Term Dryland Cropping Systems and Their Impact on Selected Soil Parameters in the Texas High Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to the decline of the Ogallala aquifer and the increasing dryland crop production, efforts are needed to enhance soil quality and functioning, and particularly water holding capacity of dryland soils in the semi-arid Texas High Plains (THP). The predominant cropping system in the THP involves dr...

  17. Different scenarios for inverse estimation of soil hydraulic parameters from double-ring infiltrometer data using HYDRUS-2D/3D

    NASA Astrophysics Data System (ADS)

    Mashayekhi, Parisa; Ghorbani-Dashtaki, Shoja; Mosaddeghi, Mohammad Reza; Shirani, Hossein; Nodoushan, Ali Reza Mohammadi

    2016-04-01

    In this study, HYDRUS-2D/3D was used to simulate ponded infiltration through double-ring infiltrometers into a hypothetical loamy soil profile. Twelve scenarios of inverse modelling (divided into three groups) were considered for estimation of Mualem-van Genuchten hydraulic parameters. In the first group, simulation was carried out solely using cumulative infiltration data. In the second group, cumulative infiltration data plus water content at h = -330 cm (field capacity) were used as inputs. In the third group, cumulative infiltration data plus water contents at h = -330 cm (field capacity) and h = -15 000 cm (permanent wilting point) were used simultaneously as predictors. The results showed that numerical inverse modelling of the double-ring infiltrometer data provided a reliable alternative method for determining soil hydraulic parameters. The results also indicated that by reducing the number of hydraulic parameters involved in the optimization process, the simulation error is reduced. The best one in infiltration simulation which parameters α, n, and Ks were optimized using the infiltration data and field capacity as inputs. Including field capacity as additional data was important for better optimization/definition of soil hydraulic functions, but using field capacity and permanent wilting point simultaneously as additional data increased the simulation error.

  18. Estimation of soil hydraulic properties based on time-lapse Ground-Penetrating Radar (GPR) measurements

    NASA Astrophysics Data System (ADS)

    Jaumann, Stefan; Klenk, Patrick; Roth, Kurt

    2015-04-01

    Recent developments brought surface-based GPR measurements to a precision that make them useful for estimating soil hydraulic properties. For this study, we estimate Mualem-Brooks-Corey parameters for a layered subsurface material distribution employing the Levenberg-Marquardt inversion algorithm. The required measurement data were recorded at our artificial test site ASSESS, where we forced the hydraulic system with a fluctuating water table and observed the dynamic deformation of the capillary fringe with time-lapse GPR. Subsequently, these measurements were simulated based on a model comprising (i) the Richards equation describing the temporal evolution of the soil hydraulic system which was solved with MUPHI, (ii) the Complex Refractive Index Model (CRIM) serving as petrophysical relationship which links the soil hydraulic model to (iii) the electrodynamic model consisting of Maxwell's equations which are solved with MEEP. For the objective function of the optimization algorithm, both measured and simulated GPR data were evaluated with a semi-automated wavelet feature detection algorithm allowing to directly compare the travel time and amplitude of the GPR signal. In this presentation, we discuss the results of the inversion based on the inversion of GPR data and we also discuss how including Time Domain Reflectometry (TDR) measurement data influences the estimated parameters.

  19. Uncertainty in the determination of soil hydraulic parameters and its influence on the performance of two hydrological models of different complexity.

    NASA Astrophysics Data System (ADS)

    Baroni, G.; Facchi, A.; Gandolfi, C.; Ortuani, B.; Horeschi, D.; van Dam, J. C.

    2009-04-01

    Measurements of soil hydraulic properties is often a limiting factor in unsaturated zone modelling, especially at the larger scales. Investigations for the hydraulic characterization of soils are troublesome and the accuracy of the results obtained by the different methodologies is still under discussion. Therefore it is licit to wonder whether, in the simulation of water dynamics in the unsaturated zone, the uncertainty in the determination of the soil hydraulic parameters could be so high to become more important than the modelling approach selected for the simulation. In order to explore this issue, in this research the data collected in an intensive monitoring activity conducted in 2006 during the cropping season of a 10 ha maize field located in Northern Italy (Landriano - PV), were used to: i) compare different methods for determining soil hydraulic parameters and ii) evaluate the effect of the uncertainty in these parameters on different outputs (i.e. evapotranspiration, water content in the root zone, fluxes through the bottom boundary of the root zone) of two hydrological models of different complexity: SWAP, a widely used model of soil moisture dynamics in unsaturated soils based on Richards equation, and ALHyMUS, a conceptual model of the same dynamics based on a reservoir cascade scheme. Five are the direct and indirect methods executed to determine soil hydraulic parameters for each horizon of the experimental profile, two based on a parameter optimization to fit: a) the laboratory measured retention and hydraulic conductivity data and b) the field measured retention and hydraulic conductivity data; and three based on the application of widely used Pedo-Transfer Functions to the measurements of texture and organic matter: c) Rawls and Brakensiek (1989); d) HYPRES (Wösten et al., 1999); and e) ROSETTA (Schaap et al., 2001). Simulations were run using meteorological, irrigation and crop data measured at the experimental site for the time period June

  20. Detailed petrophysical and geophysical characterization of core samples from the potential caprock-reservoir system in the Sulcis Coal Basin (South-Western Sardinia - Italy).

    NASA Astrophysics Data System (ADS)

    Fais, Silvana; Ligas, Paola; Cuccuru, Francesco; Maggio, Enrico; Plaisant, Alberto; Pettinau, Alberto

    2015-04-01

    The evaluation of the CO2 geologic storage site requires a robust experimental database especially with respect to spatial petrophysical heterogeneities. The integrated analysis of minero-petrographical, physical and geophysical parameters (e.g. longitudinal and transversal propagation velocity, VpVs ratio, dynamic elastic moduli, etc.) of the rocks that make up a caprock-reservoir system can substantially reduce the geologic uncertainity in the storage site characterization and in the geological and numerical modelling for the evaluation of the CO2 storage capacity. In this study the Middle Eocene - Lower Oligocene Cixerri Formation made up of siliciclastic rocks and the Upper Thanetian - Lower Ypresian Miliolitico Carbonate Complex in the Sulcis coal basin (South-Western Sardinia - Italy) have been identified respectively as potential caprock and reservoir for the CO2 storage. The petrographical, physical and geophysical parameters of the above mentioned geological Formations (Cixerri and Milolitico) were investigated to improve the geological model aimed at verifying the geological CO2 storage capacity within the carbonate reservoir rocks, in order to guarantee an efficient use of the reservoir, and to improve the numerical simulation of CO2 behaviour in the short, medium and long term after its injection in single or multiple wells. . The petrographical characteristics of the caprock-reservoir rocks were determined by optical and SEM analyses of core samples representing the different facies of the Cixerri Formation and of the Miliolitico Carbonate Complex, provided by Carbosulcis S.p.A.. Porosity analysis was completed by mercury porosimeter determinations which also provided quantitative information on the permeability of the study rocks and on the tortuosity of their pore system. Further physical properties, such as dry and saturated density and porosity, and water absorption were determined on the cylindrical core samples of intact rocks (ISRM, 1979) from

  1. Modeling the uncertainty in responsiveness of climatic, genetic, soil and agronomic parameters in CERES-Sorghum model across locations in Kansas, USA

    NASA Astrophysics Data System (ADS)

    Lamsal, A.; Anandhi, A.; Welch, S.

    2012-12-01

    Kansas leads grain sorghum production in the USA. Crop models are useful tools which provide insight about the functioning of crops, agricultural systems, and their interactions. There is a temperature and precipitation gradient across Kansas. The CERES-Sorghum model in the DSSAT system (Decision Support System for Agro-transfer Technology) was applied to many locations within the state. We hypothesize that the degree of responsiveness to CERES-Sorghum parameters would vary due to these gradients. The objective of this study is to document the uncertainties in the responsiveness of the climatic, genetic, soil and agronomic parameters in CERES-Sorghum across many locations in Kansas using multiple response variables. The input parameter categories evaluated are: climatic (temperature, solar radiation, rainfall, and CO2); genetic (P1, P2O, P5, G2, G5); agronomic (planting date, planting depth, row spacing and plant population); and soil (drained upper limit, drained lower limit, pH, saturated water content, soil organic carbon, bulk density, runoff curve number and drainage rate). Uncertainty analysis was carried out for six output response variables (yield, biomass, anthesis days, maturity days, leaf area index and leaf number) Sensitivity analysis was carried out using the OAT (one at a time) method by perturbing one input at a time keeping rest of the input parameter constant. Both relative sensitivity (a mathematical approach) and a graphical method were used, Cumulative distribution functions were used for uncertainty analysis. Preliminary results showed that, responsiveness of input parameters varied with input parameters, response variable, and location.

  2. Soil Parameter Mapping and Ad Hoc Power Analysis to Increase Blocking Efficiency Prior to Establishing a Long-Term Field Experiment.

    PubMed

    Collins, Doug; Benedict, Chris; Bary, Andy; Cogger, Craig

    2015-01-01

    The spatial heterogeneity of soil and weed populations poses a challenge to researchers. Unlike aboveground variability, below-ground variability is more difficult to discern without a strategic soil sampling pattern. While blocking is commonly used to control environmental variation, this strategy is rarely informed by data about current soil conditions. Fifty georeferenced sites were located in a 0.65 ha area prior to establishing a long-term field experiment. Soil organic matter (OM) and weed seed bank populations were analyzed at each site and the spatial structure was modeled with semivariograms and interpolated with kriging to map the surface. These maps were used to formulate three strategic blocking patterns and the efficiency of each pattern was compared to a completely randomized design and a west to east model not informed by soil variability. Compared to OM, weeds were more variable across the landscape and had a shorter range of autocorrelation, and models to increase blocking efficiency resulted in less increase in power. Weeds and OM were not correlated, so no model examined improved power equally for both parameters. Compared to the west to east blocking pattern, the final blocking pattern chosen resulted in a 7-fold increase in power for OM and a 36% increase in power for weeds. PMID:26247056

  3. Soil Parameter Mapping and Ad Hoc Power Analysis to Increase Blocking Efficiency Prior to Establishing a Long-Term Field Experiment

    PubMed Central

    Collins, Doug; Benedict, Chris; Bary, Andy; Cogger, Craig

    2015-01-01

    The spatial heterogeneity of soil and weed populations poses a challenge to researchers. Unlike aboveground variability, below-ground variability is more difficult to discern without a strategic soil sampling pattern. While blocking is commonly used to control environmental variation, this strategy is rarely informed by data about current soil conditions. Fifty georeferenced sites were located in a 0.65 ha area prior to establishing a long-term field experiment. Soil organic matter (OM) and weed seed bank populations were analyzed at each site and the spatial structure was modeled with semivariograms and interpolated with kriging to map the surface. These maps were used to formulate three strategic blocking patterns and the efficiency of each pattern was compared to a completely randomized design and a west to east model not informed by soil variability. Compared to OM, weeds were more variable across the landscape and had a shorter range of autocorrelation, and models to increase blocking efficiency resulted in less increase in power. Weeds and OM were not correlated, so no model examined improved power equally for both parameters. Compared to the west to east blocking pattern, the final blocking pattern chosen resulted in a 7-fold increase in power for OM and a 36% increase in power for weeds. PMID:26247056

  4. Unsaturated hydrologic flow parameters based on laboratory and field data for soils near the mixed waste landfill, technical area III, Sandia National Laboratories/New Mexico

    SciTech Connect

    Roepke, C.S.; Strong, W.R.; Nguyen, H.A.

    1996-08-01

    This report presents the results of laboratory tests conducted on soil core samples obtained prior to an instantaneous profile test conducted west of the Mixed Waste Landfill in Technical Area III. The instantaneous profile test was conducted to measure in situ hydrologic parameters controlling unsaturated flow and contaminant transport in the near - surface vadose zone. Soil core samples from the instantaneous profile test plot were tested in the Sandia National Laboratory`s Environmental Restoration Project Hydrology Laboratory to measure saturated hydraulic conductivity and the relationships between moisture content and soil water tension. Data from laboratory tests and the instantaneous profile field test were then modeled using the computer code RETC to quantify moisture content, soil water tension, and unsaturated hydraulic conductivity relationships. Results content, soil verified that a combination of laboratory and field data yielded a more complete definition of hydrologic properties than either laboratory or field data alone. Results also indicated that at native moisture contents, the potential for significant unsaturated aqueous flow is limited, while at saturated or near - saturated conditions, preferential flow may occur.

  5. Development of Site-Specific Soil Design Basis Earthquake (DBE) Parameters for the Integrated Waste Treatment Unit (IWTU)

    SciTech Connect

    Payne, Suzette

    2008-08-01

    Horizontal and vertical PC 3 (2,500 yr) Soil Design Basis Earthquake (DBE) 5% damped spectra, corresponding time histories, and strain-compatible soil properties were developed for the Integrated Waste Treatment Unit (IWTU). The IWTU is located at the Idaho Nuclear Technology and Engineering Center (INTEC) at the Idaho National Laboratory (INL). Mean and 84th percentile horizontal DBE spectra derived from site-specific site response analyses were evaluated for the IWTU. The horizontal and vertical PC 3 (2,500 yr) Soil DBE 5% damped spectra at the 84th percentile were selected for Soil Structure Interaction (SSI) analyses at IWTU. The site response analyses were performed consistent with applicable Department of Energy (DOE) Standards, recommended guidance of the Nuclear Regulatory Commission (NRC), American Society of Civil Engineers (ASCE) Standards, and recommendations of the Blue Ribbon Panel (BRP) and Defense Nuclear Facilities Safety Board (DNFSB).

  6. Light intensity and production parameters of phytocenoses cultivated on soil-like substrate under controled environment conditions

    NASA Astrophysics Data System (ADS)

    Tikhomirov, A.; Ushakova, S.; Gribovskaya, I.; Tirranen, L.; Manukovsky, N.; Zolotukhin, I.

    To investigate feasibility of enhancing closedness in a new generation of biological life support systems (LSS) to involve the inedible phytomass into intrasystem mass exchange the vermicomposting method we have chosen made possible to produce soil-like substrate (SLS) suitable for growing plants. However, to use the SLS in life support systems call for investigation of its physical, chemical and other parameters. Of special importance among them is the capacity of SLS to provide the LSS photosynthesizing component with required mineral elements in selected cultivation conditions. In this connection the aim of this work was to study opportunities of enhancing pr4oduction activity of wheat and radish cenoses by varying the intensity of photosynthetically active radiation (PAR) without decreasing the harvest index. Increase of light intensity to 250 W/m 2 PAR decreased the intensity of visible photosynthesis of wheat cenosi and slightly increased visible photosynthesis of radish cenosis as compared to 200 W/m 2 PAR. The maximum productivity of wheat cenosis both total and seeds corresponded to the irradiance of 200 W/m 2 PAR. The light intensity of 250 W/m2 PAR decreased productivity of wheat plants and had no significant effect of the productivity of radish cenosis as compared to 200 W/m 2 PAR. Qualitative and quantitative composition of microflora of the watering solution and SLS was determined by the condition of plants, development phase and PAR intensity. By the end of wheat vegetation under 250 W/m 2 there were an order more bacteria of the colon rod group and phytopathogenic bacteria in the watering solution and SLS than under other illumination conditions. Investigation of the mineral composition of SLS and the watering solution demonstrated that one of the reasons of inadequate response of the cenosis under study to elevated PAR intensity may be deficiency of accessible forms of some mineral elements, e.g. nitrogen. The above said materials evidence that

  7. Exploring the sensitivity on a soil area-slope-grading relationship to changes in process parameters using a pedogenesis model

    NASA Astrophysics Data System (ADS)

    Welivitiya, W. D. Dimuth P.; Willgoose, Garry R.; Hancock, Greg R.; Cohen, Sagy

    2016-08-01

    This paper generalises the physical dependence of the relationship between contributing area, local slope, and the surface soil grading using a pedogenesis model and allows an exploration of soilscape self-organisation. A parametric study was carried out using different parent materials, erosion, and weathering mechanisms. These simulations confirmed the generality of the area-slope-d50 relationship. The relationship is also true for other statistics of soil grading (e.g. d10,d90) and robust for different depths within the profile. For small area-slope regimes (i.e. hillslopes with small areas and/or slopes) only the smallest particles can be mobilised by erosion and the area-slope-d50 relationship appears to reflect the erosion model and its Shield's Stress threshold. For higher area-slope regimes, total mobilization of the entire soil grading occurs and self-organisation reflects the relative entrainment of different size fractions. Occasionally the interaction between the in-profile weathering and surface erosion draws the bedrock to the surface and forms a bedrock outcrop. The study also shows the influence on different depth-dependent in-profile weathering functions in the formation of the equilibrium soil profile and the grading characteristics of the soil within the profile. We outline the potential of this new model and its ability to numerically explore soil and landscape properties.

  8. Fungal population levels in soils of cotton fields fertilized with poultry litter and their relationships to soil nutrient concentrations and plant growth parameters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fungal population levels in soil and their relationships to nutrient concentrations and plant growth were evaluated in plots on two cotton farms in Mississippi where poultry litter (PL) was applied as a fertilizer to promote its safe disposal. Fungal population levels were estimated by dilution pla...

  9. A Novel Low-Cost Open-Hardware Platform for Monitoring Soil Water Content and Multiple Soil-Air-Vegetation Parameters

    PubMed Central

    Bitella, Giovanni; Rossi, Roberta; Bochicchio, Rocco; Perniola, Michele; Amato, Mariana

    2014-01-01

    Monitoring soil water content at high spatio-temporal resolution and coupled to other sensor data is crucial for applications oriented towards water sustainability in agriculture, such as precision irrigation or phenotyping root traits for drought tolerance. The cost of instrumentation, however, limits measurement frequency and number of sensors. The objective of this work was to design a low cost “open hardware” platform for multi-sensor measurements including water content at different depths, air and soil temperatures. The system is based on an open-source ARDUINO microcontroller-board, programmed in a simple integrated development environment (IDE). Low cost high-frequency dielectric probes were used in the platform and lab tested on three non-saline soils (ECe1: 2.5 < 0.1 mS/cm). Empirical calibration curves were subjected to cross-validation (leave-one-out method), and normalized root mean square error (NRMSE) were respectively 0.09 for the overall model, 0.09 for the sandy soil, 0.07 for the clay loam and 0.08 for the sandy loam. The overall model (pooled soil data) fitted the data very well (R2 = 0.89) showing a high stability, being able to generate very similar RMSEs during training and validation (RMSEtraining = 2.63; RMSEvalidation = 2.61). Data recorded on the card were automatically sent to a remote server allowing repeated field-data quality checks. This work provides a framework for the replication and upgrading of a customized low cost platform, consistent with the open source approach whereby sharing information on equipment design and software facilitates the adoption and continuous improvement of existing technologies. PMID:25337742

  10. A novel low-cost open-hardware platform for monitoring soil water content and multiple soil-air-vegetation parameters.

    PubMed

    Bitella, Giovanni; Rossi, Roberta; Bochicchio, Rocco; Perniola, Michele; Amato, Mariana

    2014-01-01

    Monitoring soil water content at high spatio-temporal resolution and coupled to other sensor data is crucial for applications oriented towards water sustainability in agriculture, such as precision irrigation or phenotyping root traits for drought tolerance. The cost of instrumentation, however, limits measurement frequency and number of sensors. The objective of this work was to design a low cost "open hardware" platform for multi-sensor measurements including water content at different depths, air and soil temperatures. The system is based on an open-source ARDUINO microcontroller-board, programmed in a simple integrated development environment (IDE). Low cost high-frequency dielectric probes were used in the platform and lab tested on three non-saline soils (ECe1: 2.5 < 0.1 mS/cm). Empirical calibration curves were subjected to cross-validation (leave-one-out method), and normalized root mean square error (NRMSE) were respectively 0.09 for the overall model, 0.09 for the sandy soil, 0.07 for the clay loam and 0.08 for the sandy loam. The overall model (pooled soil data) fitted the data very well (R2 = 0.89) showing a high stability, being able to generate very similar RMSEs during training and validation (RMSE(training) = 2.63; RMSE(validation) = 2.61). Data recorded on the card were automatically sent to a remote server allowing repeated field-data quality checks. This work provides a framework for the replication and upgrading of a customized low cost platform, consistent with the open source approach whereby sharing information on equipment design and software facilitates the adoption and continuous improvement of existing technologies. PMID:25337742

  11. Soil experiment

    NASA Technical Reports Server (NTRS)

    Hutcheson, Linton; Butler, Todd; Smith, Mike; Cline, Charles; Scruggs, Steve; Zakhia, Nadim

    1987-01-01

    An experimental procedure was devised to investigate the effects of the lunar environment on the physical properties of simulated lunar soil. The test equipment and materials used consisted of a vacuum chamber, direct shear tester, static penetrometer, and fine grained basalt as the simulant. The vacuum chamber provides a medium for applying the environmental conditions to the soil experiment with the exception of gravity. The shear strength parameters are determined by the direct shear test. Strength parameters and the resistance of soil penetration by static loading will be investigated by the use of a static cone penetrometer. In order to conduct a soil experiment without going to the moon, a suitable lunar simulant must be selected. This simulant must resemble lunar soil in both composition and particle size. The soil that most resembles actual lunar soil is basalt. The soil parameters, as determined by the testing apparatus, will be used as design criteria for lunar soil engagement equipment.

  12. Effective porosity and pore-throat sizes of Conasauga Group mudrock: Application, test and evaluation of petrophysical techniques

    SciTech Connect

    Dorsch, J.; Katsube, T.J.; Sanford, W.E. |; Dugan, B.E.; Tourkow, L.M.

    1996-04-01

    Effective porosity (specifically referring to the interconnected pore space) was recently recognized as being essential in determining the effectiveness and extent of matrix diffusion as a transport mechanism within fractured low-permeability rock formations. The research presented in this report was performed to test the applicability of several petrophysical techniques for the determination of effective porosity of fine-grained siliciclastic rocks. In addition, the aim was to gather quantitative data on the effective porosity of Conasauga Group mudrock from the Oak Ridge Reservation (ORR). The quantitative data reported here include not only effective porosities based on diverse measurement techniques, but also data on the sizes of pore throats and their distribution, and specimen bulk and grain densities. The petrophysical techniques employed include the immersion-saturation method, mercury and helium porosimetry, and the radial diffusion-cell method.

  13. Geology and Petrophysical Characterization of the Ferron Sandstone for 3-D Simulation of a Fluvial-Deltaic Reservoir

    SciTech Connect

    Ann Mattson; Craig B. Forster; Paul B. Anderson; Steve H. Snelgrove; Thomas C. Chidsey, Jr.

    1997-05-20

    The objective of this project is to develop a comprehensive, interdisciplinary, and quantitative characterization of a fluvial-deltaic reservoir which will allow realistic inter-well and reservoir-scale modeling to be constructed for improved oil-field development in similar reservoirs world-wide. The geological and petrophysical properties of the Cretaceous Ferron Sandstone in east-central Utah will be quantitatively determined. Both new and existing data will be integrated into a three-dimensional representation of spatial variations in porosity, storativity, and tensorial rock permeability at a scale appropriate for inter-well to regional-scale reservoir simulation. Four activities continued this quarter as part of the geological and petrophysical characterization of the fluvial-deltaic Ferron Sandstone in the Ivie Creek case-study area: (1) regional stratigraphic interpretation, (2) case-study evaluation, (3) reservoir modeling, and (4) technology transfer.

  14. Combined geophysical and petrophysical characterization to support a hydrogeological model of a coastal environment

    NASA Astrophysics Data System (ADS)

    Burschil, Thomas; Wiederhold, Helga; Scheer, Wolfgang; Kirsch, Reinhard; Krawczyk, Charlotte M.

    2014-05-01

    Global warming affects the water cycle by changing precipitation/evaporation and raising sea level. Especially groundwater systems in sensitive environments, such as coastal areas or barrier islands, have to be evaluated with respect to the potential reduction of water quality, e.g. salinization by saltwater intrusion (Hinsby et al., 2012). To assess these hazards using groundwater modeling we need a strong base of hydraulic and hydrogeological information. The use of integrated geophysical methods, in combination with a petrophysical characterization, provides a reliable architecture for groundwater modeling. Within the EU-project CLIWAT, we investigated the hydrogeological situation of the North Sea island of Föhr in Schleswig-Holstein (Germany). The island was mainly formed during glaciations in Pleistocene Series, especially Saalian and Weichselian Stages. These deposits remain as a Geest core in the southern central part, and house a freshwater lens that is used for the local water supply. To investigate the architecture of the fresh water lens, we carried out several surveys with airborne electromagnetic (AEM), seismic reflection, and borehole methods. To enhance the AEM resistivity model we inverted the data with a-priori constraints from seismic reflections (Burschil et al., 2012a). This constrained inversion leads to, among other things, a separation of two aquifers by resistivity data. Additionally, from borehole logs, vertical seismic profiles (VSP), and nearby AEM inversion point models we are able to petrophysically characterize different lithological categories regarding resistivity and seismic velocity. Subsurface glacial structures, e.g. buried valleys and a push moraine complex, are mapped down to 150 m below sea level. Below this rather horizontal features indicate Tertiary layers. Geophysically determined petrophysical values were correlated with lithological categories to enhance the interpretation of geophysical data. In this way, we expose

  15. Petrophysical Analysis and Geographic Information System for San Juan Basin Tight Gas Reservoirs

    SciTech Connect

    Martha Cather; Robert Lee; Robert Balch; Tom Engler; Roger Ruan; Shaojie Ma

    2008-10-01

    The primary goal of this project is to increase the availability and ease of access to critical data on the Mesaverde and Dakota tight gas reservoirs of the San Juan Basin. Secondary goals include tuning well log interpretations through integration of core, water chemistry and production analysis data to help identify bypassed pay zones; increased knowledge of permeability ratios and how they affect well drainage and thus infill drilling plans; improved time-depth correlations through regional mapping of sonic logs; and improved understanding of the variability of formation waters within the basin through spatial analysis of water chemistry data. The project will collect, integrate, and analyze a variety of petrophysical and well data concerning the Mesaverde and Dakota reservoirs of the San Juan Basin, with particular emphasis on data available in the areas defined as tight gas areas for purpose of FERC. A relational, geo-referenced database (a geographic information system, or GIS) will be created to archive this data. The information will be analyzed using neural networks, kriging, and other statistical interpolation/extrapolation techniques to fine-tune regional well log interpretations, improve pay zone recognition from old logs or cased-hole logs, determine permeability ratios, and also to analyze water chemistries and compatibilities within the study area. This single-phase project will be accomplished through four major tasks: Data Collection, Data Integration, Data Analysis, and User Interface Design. Data will be extracted from existing databases as well as paper records, then cleaned and integrated into a single GIS database. Once the data warehouse is built, several methods of data analysis will be used both to improve pay zone recognition in single wells, and to extrapolate a variety of petrophysical properties on a regional basis. A user interface will provide tools to make the data and results of the study accessible and useful. The final deliverable

  16. Mapping of a buried basement combining aeromagnetic, gravity and petrophysical data: The substratum of southwest Paris Basin, France

    NASA Astrophysics Data System (ADS)

    Baptiste, Julien; Martelet, Guillaume; Faure, Michel; Beccaletto, Laurent; Reninger, Pierre-Alexandre; Perrin, José; Chen, Yan

    2016-06-01

    Aeromagnetic and gravity data have proven to be among the most effective methods for mapping deeply buried basin/basement interfaces. However, the data interpretation generally suffers from ambiguities, due to the non-uniqueness of the gravity and magnetic signatures. Here, we tie the gravity and magnetic signatures with a petrophysical characterization of the lithologies outcropping around the French Paris Basin. Our methodology investigates the lithology and structure of its hidden Variscan substratum at the junction between the Armorican Massif and Massif Central. Our approach is based on the combination of potential field data, magnetic susceptibilities measured in the field, density values of sample rocks and information documented in boreholes, in order to propose a new interpretative geological map of the buried substratum of the Paris Basin. The petrophysical description is combined with geophysical patterns of the substratum, mapped through statistical unsupervised classification of suitably selected magnetic and gravity maps. The first step of interpretation consists in extending the outcropping major structures below the Meso-Cenozoic sedimentary cover of the Paris Basin. The litho-structural units, in between these major structures, are then interpreted separately. The second step consists in assigning lithologies within each unit, with respect to its magnetization and density (as derived from the petrophysical compilation), and mapping its extension under cover, integrating punctual borehole information. Overall, with a special emphasis on relating geophysical signatures and petrophysical characteristics of litho-structural units, this methodology permits a precise structural and lithological cartography of a segment of the buried Variscan substratum. In the southwestern part of the Paris Basin, this approach reveals: i) the limited eastward extension of Central Brittany, ii) the eastward extension of the major Cholet fault, iii) the emphasis on N150E

  17. Pore Network Simulation to Develop Electrical Petrophysical Relations in the Presence of Mass Transfer

    NASA Astrophysics Data System (ADS)

    Day-Lewis, F. D.; Haggerty, R.; Singha, K.; Binley, A.; Swanson, R. D.; Clifford, J.; Lane, J. W.; Ward, A. L.; Johnson, T. J.

    2011-12-01

    In both field and laboratory settings, time-lapse electrical measurements have indicated rate-limited mass transfer of ionic tracer between mobile and immobile (or less mobile) domains in porous media over a range of flow rates and time scales. In previous work, a simple bicontinuum extension of Archie's Law was used to relate direct-current bulk conductivity and fluid conductivity assuming that the mobile and immobile domains contribute as conductors in parallel with weights given by porosity fraction; however, other petrophysical models may account for the effect of internal connectivity of each domain on its relative contribution to bulk conductivity. Additional work is required to (1) evaluate the bicontinuum Archie formulation relative to these other models for bulk conductivity of multiphase (i.e., multidomain) media with application to mass-transfer problems, and (2) characterize the geoelectrical signature of mass transfer for porous media with different pore geometries and electrical properties. To address this long standing problem, we developed a coupled fluid flow, electrical conduction, and solute transport simulator for two-dimensional pore networks. The pore space is modeled as a pipe lattice where pipes are square in cross section with widths drawn from random distributions. Pipe conductances for the fluid flow problem are assigned according to Hagen-Pouseuille flow, and the conservation problem is solved. Alternative to computationally intensive simulation of transient advective-dispersive transport, we adopt a more efficient but approximate two-step approach. First, we find the zeroth and first temporal moments throughout the network by solving sequentially two steady-state transport problems; from these results we calculate mean arrival time for each node in the network. Second, we convert the calculated mean arrival times to mass-transfer rates for input to a semi-analytical multi-rate mass transfer model to simulate gross transport through a

  18. Improvement of growth of Eucalyptus globulus and soil biological parameters by amendment with sewage sludge and inoculation with arbuscular mycorrhizal and saprobe fungi.

    PubMed

    Arriagada, C; Sampedro, I; Garcia-Romera, I; Ocampo, J

    2009-08-15

    Sewage sludge is widely used as an organic soil amendment to improve soil fertility. We investigated the effects of sewage sludge (SS) application on certain biological parameters of Eucalyptus globulus Labill. The plant was either uninoculated or inoculated with saprobe fungi (Coriolopsis rigida and Trichoderma harzianum) or arbuscular mycorrhizal (AM) fungi (Glomus deserticola and Gigaspora rosea). Sewage sludge was applied to the surface of experimental plots at rates of 0, 2, 4, 6 and 8 g 100 g(-1) of soil. Inoculation with both AM and saprobe fungi in the presence of SS was essential for the promotion of plant growth. The AM, saprobe fungi and SS significantly increased dry shoot weight. The AM fungi induced a significant increase in Fluorescein diacetate (FDA) activity but did not increase beta-glucosidase activity. Addition of SS to AM-inoculated soil did not affect either FDA or alpha-glucosidase activities in plants from soil that was either uninoculated or inoculated with the saprobe fungi. SS increased beta-glucosidase activity when it was applied at 4 g 100 g(-1). SS negatively affected AM colonization as well as the mycelium SDH activity for both mycorrhizal fungi. SS increased Eucalyptus shoot biomass and enhanced its nutrient status. Inoculation of the soil with G. deserticola stimulated significant E. globulus growth and increases in shoot tissue content of N, P, K, Ca, Mg and Fe. Dual inoculation with G. deserticola and either of the saprobe fungi had positive effects on K, Ca, Mg and Fe contents. The application of 8 g 100 g(-1) of SS had no positive effects on plant nutrition. The experimental setup provided a suitable tool for evaluating SS in combination with saprobe and AM fungi as a biological fertiliser for its beneficial effects on E. globulus plant growth. PMID:19515400

  19. Optimal Land Use Management for Soil Erosion Control by Using an Interval-Parameter Fuzzy Two-Stage Stochastic Programming Approach

    NASA Astrophysics Data System (ADS)

    Han, Jing-Cheng; Huang, Guo-He; Zhang, Hua; Li, Zhong

    2013-09-01

    Soil erosion is one of the most serious environmental and public health problems, and such land degradation can be effectively mitigated through performing land use transitions across a watershed. Optimal land use management can thus provide a way to reduce soil erosion while achieving the maximum net benefit. However, optimized land use allocation schemes are not always successful since uncertainties pertaining to soil erosion control are not well presented. This study applied an interval-parameter fuzzy two-stage stochastic programming approach to generate optimal land use planning strategies for soil erosion control based on an inexact optimization framework, in which various uncertainties were reflected. The modeling approach can incorporate predefined soil erosion control policies, and address inherent system uncertainties expressed as discrete intervals, fuzzy sets, and probability distributions. The developed model was demonstrated through a case study in the Xiangxi River watershed, China's Three Gorges Reservoir region. Land use transformations were employed as decision variables, and based on these, the land use change dynamics were yielded for a 15-year planning horizon. Finally, the maximum net economic benefit with an interval value of [1.197, 6.311] × 109 was obtained as well as corresponding land use allocations in the three planning periods. Also, the resulting soil erosion amount was found to be decreased and controlled at a tolerable level over the watershed. Thus, results confirm that the developed model is a useful tool for implementing land use management as not only does it allow local decision makers to optimize land use allocation, but can also help to answer how to accomplish land use changes.

  20. Site-specific analysis of radiological and physical parameters for cobbly soils at the Gunnison, Colorado, processing site

    SciTech Connect

    Not Available

    1993-10-01

    The remedial action at the Gunnison, Colorado, processing site is being performed under the Uranium Mill Tailings Radiation Control Act (UMTRCA) of 1978 [Public Law (PL) 95-6041]. Under UMTRCA, the US Environmental Protection Agency (EPA) is charged with the responsibility of developing appropriate and applicable standards for the cleanup of radiologically contaminated land and buildings at 24 designated sites, including the Gunnison, Colorado, inactive processing site. The remedial action at the processing site will be conducted to remove the tailings and contaminated materials to meet the EPA bulk soil cleanup standards for surface and subsurface soils. The site areas disturbed by remedial action excavation will be either contoured or backfilled with radiologically uncontaminated soil and contoured to restore the site. The final contours will produce a final surface grade that will create positive drainage from the site.

  1. Spatial analysis of soil and shallow groundwater physicochemical parameters in El-Mujib Basin-central Jordan

    NASA Astrophysics Data System (ADS)

    Salman, Abeer; Al-Qinna, Mohammed; Kuisi, Mustafa Al

    2014-01-01

    In this study statistical and geostatistical methods were applied to a monitoring data set in order to assess contamination risk in soil and shallow groundwater. The study covered an area within El-Mujib Basin in central Jordan, where the barren land is dominating with a small number of irrigated areas in the vicinity of Wadi El-Mujib and in the northern part of the basin. A total of 77 soil and 104 water samples were collected randomly and analyzed physically, chemically, statistically and spatially using ordinary and indicator kriging techniques. Phosphate, nitrate, organic matter and effective field capacity in the soil system were spatially investigated and correlated to current landuse. Maximum soil maximum nitrate (125.6 mg/L), phosphate (9.7 mg/L), and organic matter (3%) contents are encountered in the central area at Wadi El-Mujib, Qattrana and Umm Rasas due to the use of fertilizers and existence of solid landfill. The soil has low water holding capacity as it is dominated by coarse texture and therefore subjecting the groundwater for potential risks through the fast soil system. The major cations and anions in the groundwater were mainly concentrated in the Wadi El-Mujib and in the central part of the Basin increases along the groundwater flow direction. Spatial groundwater indicator maps of salinity; nitrate and sulfate contents proves the high susceptibility of the study area to be contaminated. By determining the impacts, more effective (specific to contamination sources) measures for preventing groundwater quality could be implemented.

  2. Influence of variable topsoil replacement depths on soil chemical parameters within a coal mine in northeastern Wyoming, USA

    SciTech Connect

    Schladweiler, B.K.; Vance, G.F.; Legg, D.E.; Munn, L.C.; Haroian, R.

    2004-10-15

    Uniform topsoil replacement depths on coal mine reclaimed areas have been mandated by USA federal and state regulations; however, soils of the premine landscape are not naturally uniform in depth and vary in physical, chemical, and biological characteristics. In addition, uniform topsoil depths may actually hinder the development of diverse reclaimed plant communities. We studied the effect of varying topsoil replacement depth treatments (15, 30, and 56 cm) on soil and backfill pH, electrolytic conductivity (EC), and sodium adsorption ratio (SAR) within a reclaimed coal mine study area. Backfill material (also known as spoil) at this site did not possess levels of pH, EC, and SAR that were detrimental to plant growth. There was only a slight reduction in pH, EC, and SAR within the upper 15 cm depth in the reclaimed topsoil treatments with a general increase of EC and SAR in the lower portion of the replaced soil profile. Some downward movement of soluble salts within the reclaimed treatments was evident despite low precipitation. For examples, SAR in the 0-15 cm depth over all reclaimed treatments was lower in 2002 than 2000-2001, and the 0-30 cm portion of the reclaimed soil profile had reduced pH and EC, while the 30-60 cm portion had increased EC and SAR. It is anticipated that soil quality differences in terms of pH, EC, and SAR between topsoil depth treatments will be enhanced with time. Comparison of the reclaimed area to the native reference areas suggested numerous depth differences as a result of homogeneity of the replaced topsoil vs. undisturbed soil profiles.

  3. Defining and modeling the soil geochemical background of heavy metals from the Hengshi River watershed (southern China): integrating EDA, stochastic simulation and magnetic parameters.

    PubMed

    Zhou, Xu; Xia, Beicheng

    2010-08-15

    It is crucial to separate the soil geochemical background concentrations from anthropogenic anomalies and to provide a realistic environmental geochemical map honoring the fluctuations in original data. This study was carried out in the Hengshi River watershed, north of Guangdong, China and the method proposed combined exploratory data analysis (EDA), sequential indicator co-simulation (SIcS) and the ratio of isothermal remnant magnetization (S(100)=-IRM(-100 mT)/SIRM). The results showed that this is robust procedure for defining and mapping soil geochemical background concentrations in mineralized regions. The rock magnetic parameter helps to improve the mapping process by distinguishing anthropogenic influences. In this study, the geochemical backgrounds for four potentially toxic heavy metals (copper 200mg/kg; zinc 23 0mg/kg; lead 190 mg/kg and cadmium 1.85 mg/kg) Cu, Zn and Cd exceeded the soil Grade II limits (for pH<6.5) from the Chinese Environmental Quality Standard for Soils (GB 15618-1995) (EQSS) which are 100, 200, 250 and 0.3mg/kg for Cu, Zn, Pb and Cd, respectively. In particular, the geochemical background level for Cd exceeds standard six times. Results suggest that local public health is at high-risk along the riparian region of the Hengshi River, although the watershed ecosystem has not been severely disturbed. PMID:20471164

  4. Effect of Remediation Parameters on in-Air Ambient Dose Equivalent Rates When Remediating Open Sites with Radiocesium-contaminated Soil.

    PubMed

    Malins, Alex; Kurikami, Hiroshi; Kitamura, Akihiro; Machida, Masahiko

    2016-10-01

    Calculations are reported for ambient dose equivalent rates [H˙*(10)] at 1 m height above the ground surface before and after remediating radiocesium-contaminated soil at wide and open sites. The results establish how the change in H˙*(10) upon remediation depends on the initial depth distribution of radiocesium within the ground, on the size of the remediated area, and on the mass per unit area of remediated soil. The remediation strategies considered were topsoil removal (with and without recovering with a clean soil layer), interchanging a topsoil layer with a subsoil layer, and in situ mixing of the topsoil. The results show the ratio of the radiocesium components of H˙*(10) post-remediation relative to their initial values (residual dose factors). It is possible to use the residual dose factors to gauge absolute changes in H˙*(10) upon remediation. The dependency of the residual dose factors on the number of years elapsed after fallout deposition is analyzed when remediation parameters remain fixed and radiocesium undergoes typical downward migration within the soil column. PMID:27575348

  5. Combining Forces - The Use of Landsat TM Satellite Imagery, Soil Parameter Information, and Multiplex PCR to Detect Coccidioides immitis Growth Sites in Kern County, California

    PubMed Central

    Lauer, Antje; Talamantes, Jorge; Castañón Olivares, Laura Rosío; Medina, Luis Jaime; Baal, Joe Daryl Hugo; Casimiro, Kayla; Shroff, Natasha; Emery, Kirt W.

    2014-01-01

    Coccidioidomycosis is a fungal disease acquired through the inhalation of spores of Coccidioides spp., which afflicts primarily humans and other mammals. It is endemic to areas in the southwestern United States, including the San Joaquin Valley portion of Kern County, California, our region of interest (ROI). Recently, incidence of coccidioidomycosis, also known as valley fever, has increased significantly, and several factors including climate change have been suggested as possible drivers for this observation. Up to date details about the ecological niche of C. immitis have escaped full characterization. In our project, we chose a three-step approach to investigate this niche: 1) We examined Landsat-5-Thematic-Mapper multispectral images of our ROI by using training pixels at a 750 m×750 m section of Sharktooth Hill, a site confirmed to be a C. immitis growth site, to implement a Maximum Likelihood Classification scheme to map out the locations that could be suitable to support the growth of the pathogen; 2) We used the websoilsurvey database of the US Department of Agriculture to obtain soil parameter data; and 3) We investigated soil samples from 23 sites around Bakersfield, California using a multiplex Polymerase Chain Reaction (PCR) based method to detect the pathogen. Our results indicated that a combination of satellite imagery, soil type information, and multiplex PCR are powerful tools to predict and identify growth sites of C. immitis. This approach can be used as a basis for systematic sampling and investigation of soils to detect Coccidioides spp. PMID:25380290

  6. Modelling Hydrologic Fluxes on the Yangtze River Basin Using Satellite and Ground Data: Soil Calibration Parameters Using Satellite Land Surface Temperature

    NASA Astrophysics Data System (ADS)

    Corbari, Chiara; Mancini, Marco; Li, Jiren; Su, Bob

    2014-11-01

    A fully distributed hydrological model FEST-EWB will be calibrated assimilating satellite-based LST to calibrate soil and vegetation parameters in each pixel of the domain as a complementary method to the traditional calibration with local SM data. This is feasible because the model algorithm solves the system of energy and mass balances in terms of a representative equilibrium temperature (RET) that is the land surface temperature that closes the energy balance equation and so governs the fluxes of energy and mass over the basin domain. This equilibrium surface temperature, which is a critical model state variable, is comparable to LST as retrieved from operational remote sensing data (MODIS and AATSR) which is used for the calibration of soil and vegetation parameters. FEST-EWB is run in for the whole Yangtze River basin at spatial resolution of 0.05° and temporal resolution of 3 hours. Results are provided in terms of hourly evapotranspiration, soil moisture and land surface temperature maps for the period between 2003 to 2006. The effects on river discharge of the Three Gorges dam, the largest hydropower project in the world, will be evaluated as well as of the three large lakes (Poyang, Dongting and Taihu) which change considerably their area during the seasons (MERIS). Observed flow duration curves, for the four available river cross sections, will be evaluated and compared to FEST-EWB simulated flow duration curves as well as observed as simulated hydrographs.

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

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

    A procedure is presented for calculating 24-hour totals of evaporation from wet and drying soils. Its application requires a knowledge of the daily solar radiation, the maximum and minimum, air temperatures, moist surface albedo, and maximum and minimum surface temperatures. Tests of the technique on a bare field of Avondale loam at Phoenix, Arizona showed it to be independent of season.

  8. Approaching the Petrophysics of deep Earth's and Earth-like Planetary Interior

    NASA Astrophysics Data System (ADS)

    Mueller, H. J.; Lauterjung, J.; Lathe, C.

    2015-12-01

    The Earth's deep interior is only accessible by indirect methods, first and foremost seismological studies. The interpretation of these seismic data and the corresponding numerical modelling require measurements of the elastic and inelastic properties of representative Earth materials under experimental simulated in-situ pressure-temperature conditions. Seismic tomography studies and corresponding numerical models have demonstrated that under certain conditions subducting slabs can even reach the core mantle boundary. That means former crustal rocks became heavily overprinted by increasing pressure, temperature, deformation and partial material exchange. Because there is no known geodynamic mechanism able to bring them back to the surface as a whole, we cannot sample them. But there is no indication to assume they are simpler than their parental rocks - quite the contrary. I think the first-order future challenge for large volume geophysical high pressure research is to measure data for an understanding of the relation between structural and physical properties of these complex polymineral rock-like assemblages. The paper presents the results of petrophysical transient experiments with natural rocks under uppermost mantle conditions and first steps to perform in-situ experiments under deep mantle conditions.

  9. Petrophysical studies of north American carbonate rock samples and evaluation of pore-volume compressibility models

    NASA Astrophysics Data System (ADS)

    da Silva, Gilberto Peixoto; Franco, Daniel R.; Stael, Giovanni C.; da Costa de Oliveira Lima, Maira; Sant'Anna Martins, Ricardo; de Moraes França, Olívia; Azeredo, Rodrigo B. V.

    2015-12-01

    In this work, we evaluate two pore volume compressibility models that are currently discussed in the literature (Horne, 1990; Jalalh, 2006b). Five groups of carbonate rock samples from the three following sedimentary basins in North America that are known for their association with hydrocarbon deposits were selected for this study: (i) the Guelph Formation of the Michigan Basin (Middle Silurian); (ii) the Edwards Formation of the Central Texas Platform (Middle Cretaceous); and (iii) the Burlington-Keokuk Formation of the Mississippian System (Lower Mississippian). In addition to the evaluation of the compressibility model, a petrophysical evaluation of these rock samples was conducted. Additional characterizations, such as grain density, the effective porosity, absolute grain permeability, thin section petrography, MICP and NMR, were performed to complement constant pore-pressure compressibility tests. Although both models presented an overall good representation of the compressibility behavior of the studied carbonate rocks, even when considering their broad porosity range (~ 2-38%), the model proposed by Jalalh (2006b) performed better with a confidence level of 95% and a prediction interval of 68%.

  10. Estimation of petrophysical and fluid properties using integral transforms in nuclear magnetic resonance.

    PubMed

    Gruber, Fred K; Venkataramanan, Lalitha; Habashy, Tarek M; Freed, Denise E

    2013-03-01

    In the past decade, low-field NMR relaxation and diffusion measurements in grossly inhomogeneous fields have been used to characterize properties of porous media, e.g., porosity and permeability. Pulse sequences such as CPMG, inversion and saturation recovery as well as diffusion editing have been used to estimate distribution functions of relaxation times and diffusion. Linear functionals of these distribution functions have been used to predict petro-physical and fluid properties like permeability, viscosity, fluid typing, etc. This paper describes an analysis method using integral transforms to directly compute linear functionals of the distributions of relaxation times and diffusion without first computing the distributions from the measured magnetization data. Different linear functionals of the distribution function can be obtained by choosing appropriate kernels in the integral transforms. There are two significant advantages of this approach over the traditional algorithm involving inversion of the distribution function from the measured data. First, it is a direct linear transform of the data. Thus, in contrast to the traditional analysis which involves inversion of an ill-conditioned, non-linear problem, the estimates from this new method are more accurate. Second, the uncertainty in the linear functional can be obtained in a straight-forward manner as a function of the signal-to-noise ratio (SNR) in the measured data. We demonstrate the performance of this method on simulated data. PMID:23369701

  11. Diagenetic evolution and petrophysical characteristics of oomoldic facies in United States and Middle East reservoirs

    SciTech Connect

    Nurmi, R.; Neuberger, D.

    1987-08-01

    The diagenetic evolution of oomoldic pore rocks from US and Middle East reservoirs were studied to determine their variation. The oomolds in all of the reservoir samples appear to have formed prior to any compaction, and were also subject to early cementation, which preserved the delicate structure of these rocks. The most common oomold-filling mineral is calcite, regardless of whether the remainder of the rock is dolostone or limestone. Anhydrite is commonly the mineral filling oomolds in formations depositionally associated with evaporites. Partial cementation of individual oomolds is rare. However, partial filling of oomoldic wackestones by lime mud was observed. The petrophysical characteristics of oomoldic rocks in different stages of diagenetic evolution were analyzed using thin sections, pore casts, porosity and permeability measurements, and saturation. The rocks used in the study included core samples from the Lansing-Kansas City Group, San Andres, Smackover, Arab, and Khuff formations. Selected samples from the Lansing-Kansas City Groups were also measured for formation factor, density, and for dielectric and acoustic properties. The study quantified the relationship of pore type and volume with both formation factor and permeability of oomoldic rocks. The framework mineralogy (calcite or dolomite) and microstructure, and the presence and nature of interparticle pore-filling cements are critical factors in assessing the reservoir potential of an oomoldic reservoir facies. Furthermore, the geologic analysis of the pore system can greatly improve the determination of the Archie m exponent, which provides more reasonable evaluations of the saturation and permeability of these complex rocks.

  12. Petrologic-petrophysical-engineering relationships, selected wells near the Arctic National Wildlife Refuge, Alaska

    SciTech Connect

    Mowatt, T.C.; Gibson, C.; Seidlitz, A.; Bascle, R.; Dygas, J. )

    1991-03-01

    In the context of the reservoir management and resource assessment programs of the U.S. Bureau of Land Management in Alaska, selected stratigraphic horizons were studied in a number of wells adjacent to the Arctic National Wildlife Refuge (ANWR), northeast Alaska. Petrographic analyses were integrated with petrophysical and engineering data, in order to provide a substantive knowledge base from which to infer reservoir potentials elsewhere in the region, using geological and geophysical methods. Of particular interest in the latter regard is the ANWR area. Horizons of concern with regard to reservoir characteristics include Franklinian through Brookian strata. Of particular interest are clastic Ellesmerian 'Break-up/Rift Sequence' sediments such as the Lower Cretaceous Thomson sand, and deeper-water marine clastics, as exemplified by the Brookian Colville Group 'turbidites.' Also of concern are pre-Ellesmerian 'basement' rocks, some of which are hosts to hydrocarbon accumulations in the Point Thomson field. Petrologic-mineralogic characteristics have been keyed to various wireline log responses and related to available engineering data, as feasible, for the wells considered. Synthesis of this information in terms of the regional geological framework, tied in with geophysical data, will facilitate more refined, effective resource assessment and management.

  13. Computational challenges in the analyses of petrophysics using microtomography and upscaling: A review

    NASA Astrophysics Data System (ADS)

    Liu, Jie; Pereira, Gerald G.; Liu, Qingbin; Regenauer-Lieb, Klaus

    2016-04-01

    Microtomography provides detailed 3D internal structures of materials in micro- to tens of nano-meter resolution and is quickly turning into a new technology for studying petrophysical properties of rocks. An important step is the upscaling of these properties as micron or sub-micron resolution can only be achieved on the sample-scale of millimeters or even less than a millimeter. We have developed a computational workflow for the analysis of microstructures including the upscaling of material properties. Computations of properties are first performed using conventional material science simulations at micro to nano-scale. The subsequent upscaling of these properties is done by a novel renormalization procedure based on percolation theory. In this paper we discuss the computational challenges arising from the workflow, which include: 1) characterization of microtomography for extremely large data sets; 2) computational fluid dynamics simulations at pore-scale for permeability estimation; 3) solid mechanical computations at pore-scale for estimating elasto-plastic properties; 4) Extracting critical exponents from derivative models for scaling laws. We conclude that significant progress in each of these challenges is necessary to transform microtomography from the current research problem into a robust computational big data tool for multi-scale scientific and engineering problems.

  14. Exploring Critical Assumptions of Petrophysical Models in Fractured Aquifers by Comparing Estimated Porosity Values Obtained from Surface Nuclear Magnetic Resonance and Shallow Seismic Refraction Surveys.

    NASA Astrophysics Data System (ADS)

    Flinchum, B. A.; Holbrook, W. S.; Grana, D.; Parsekian, A.

    2015-12-01

    Estimating subsurface porosity from most near-surface geophysical techniques relies on petrophysical relationships. Using petrophysical relationships are challenging because they require many assumptions and oftentimes require site-specific constants. Despite complexities and challenges, the petrophysical relationships are critical to convert the measurable physical properties into hydrologic properties such as porosity, water content and ultimately hydraulic conductivity. In this study we compare porosities derived from shallow seismic refraction (SSR) and surface nuclear magnetic resonance (SNMR) in a fractured granite aquifer in the Laramie Range, Wyoming. To estimate porosity from the SSR data we use a Bayesian inversion based on Hertz-Mindlin contact theory and Hashin- Strickman boundaries. This type of petrophysical model requires us to make assumptions about the grain structure, mineralogy and water content. Using water table measurements from a borehole we assume that all pores are fully saturated below 10 meters, thus the SNMR measurement provides an estimate of porosity. If the petrophysical model and the assumptions that are required to use it were correct and the SNMR measurements were perfect, the estimates of porosities derived from two distinct physical measurements should provide the same porosity. Interestingly, we observe a large discrepancy in the porosities derived from this unique combination of measurements. At depths of 10 to 20 meters, the area that we interpret as fractured bedrock and where the assumption of fully saturated pores holds, the SSR predicted porosities are 15 to 20 % higher than those predicted by SNMR. Previous comparisons of the Bayesian inversion have shown it does well to predict porosity within the saprolite. The large discrepancy illustrates the need to use separate petrophysical models in the weathered and fractured zones of granite aquifers. More research is needed to figure out how to combine different petrophysical

  15. Effect of simultaneous state-parameter estimation and forcing uncertainties on root-zone soil moisture for dynamic vegetation using EnKF

    NASA Astrophysics Data System (ADS)

    Monsivais-Huertero, Alejandro; Graham, Wendy D.; Judge, Jasmeet; Agrawal, Divya

    2010-04-01

    In this study, an EnKF-based assimilation algorithm was implemented to estimate root-zone soil moisture (RZSM) using the coupled LSP-DSSAT model during a growing season of corn. Experiments using both synthetic and field observations were conducted to understand effects of simultaneous state-parameter estimation, spatial and temporal update frequency, and forcing uncertainties on RZSM estimates. Estimating the state-parameters simultaneously with every 3-day assimilation of volumetric soil moisture (VSM) observations at 5 depths lowered the average standard deviation (ASD) and the root mean square error (RMSE) for RZSM by approximately 1.77% VSM (78%) and 2.18% VSM (93%), respectively, compared to the open-loop ASD where as estimating only states lowered the ASD by approximately 1.26% VSM (56%) and the RMSE by 1.66% VSM (71%). The synthetic case obtained RZSM estimates closer to the observations than the MicroWEX-2 case, particularly after precipitation/irrigation events. The differences in EnKF performance between MicroWEX-2 and synthetic observations may indicate other sources of errors in addition to those in parameters and forcings, such as errors in model biophysics.

  16. Aircraft remote sensing of soil moisture and hydrologic parameters, Taylor Creek, Florida, and Little River, Georgia, 1979 data report

    NASA Technical Reports Server (NTRS)

    Jackson, T. J.; Schmugge, T. J.; Allen, L. H., Jr.; Oneill, P.; Slack, R.; Wang, J.; Engman, E. T.

    1981-01-01

    Experiments were conducted to evaluate aircraft remote sensing techniques for hydrology in a wide range of physiographic and climatic regions using several sensor platforms. The data were collected in late 1978 and during 1979 in two humid areas--Taylor Creek, Fla., and Little River, Ga. Soil moisture measurements and climatic observations are presented as well as the remote sensing data collected using thermal infrared, passive microwave, and active microwave systems.

  17. Influence of petrophysical parameters on eruption dynamics: a rheological study of the erupted products of Mt. Yasur, Vanuatu

    NASA Astrophysics Data System (ADS)

    Hanson, J. B.; Kremers, S. B.; Lavallee, Y.; Hess, K.; Dingwell, D. B.

    2011-12-01

    Mt. Yasur (Tanna, Vanuatu) is a small scoria cone (360 m high) and one of the most persistently active volcanoes worldwide. During the last ~10.000 years, Mt.Yasur mostly produced strong strombolian to vulcanian eruptions intercalated by sub-plinian eruptions every ca. 40 years. During a 6-week field campaign in August-September 2008, we installed four seismic and four infrasound arrays on site to record seismic and acoustic signals. Two Doppler-Radars measured the exit velocities of the erupted material, and a thermal camera was used to determine the temperature at the vent mouth. At the time of the fieldwork, three active craters showed very different styles of activity. Crater A, the most active vent, had an eruption recurrence of under a minute. Crater B showed very irregular ash-venting, while crater C was producing the strongest eruptions every 10 minutes. We sampled the eruptive products of craters A and C for further analysis in the lab. In total, three bombs were collected in order to investigate the chemical, physical, rheological and textural variations in the erupted products from the different craters. The collected basaltic-andesite scoria bombs exhibit a relatively constant whole rock major element geochemistry (~56 wt.% SiO2); correspondingly, the remelted whole rock viscosity, investigated via a combination of concentric cylinder rheometry and micropenetration, remains similar. Petrographic texture and structure analyses reveal a large variation in porosity (~30 - 78 %) and microlite content. Observation of aphyric zones grading abruptly or incrementally (on mm to cm scales) to nearly entirely crystalline zones suggest the occurrence of mingling and mixing of magma batches with different crystallization histories. The microlites are mostly anhydral, showing and needle-like growth pattern, with signs of kinetic growth disequilibrium similar to spherulites. Interstitial glass chemistry from electron microprobe analysis shows a range of glass chemistry from 59-63 wt.% SiO2, with less-evolved glass generally being associated with areas of higher crystal content. Combining the estimation of the calorimetric glass transition temperature at (600 °C at 10 °C/min) with the observed crystal growth disequilibrium emphasizes the proximity of the eruptive temperature conditions to the glass transition interval. We discuss the potential distinction in eruptive behaviour from the variation in crystal assemblages and rheologies.

  18. Towards the Petrophysics and Petrology of Earth's Deep Mantle and the Core Mantle Boundary

    NASA Astrophysics Data System (ADS)

    Mueller, H. J.

    2010-12-01

    Petrophysics measures the physical properties of rocks. Petrology investigates the physical and chemical conditions of their formation as well as attempts to unscramble the p-T-path of a multi-phase development. Petrology is focussed on investigating the shifting equilibrium conditions between the different minerals constituting the crystalline rocks. Because the knowledge is mostly derived from powder high pressure experiments the perspective is mainly chemical and mineralogical. On the other hand experimental petrophysics only exists because structure and texture of a real rock has a vast influence on the resulting physical properties, i.e. the physical rock properties cannot simply derived from the properties of a mixture of the rock constituting minerals. From seismic tomography we know, subduction can reach the core mantle boundary and results in geochemical piles there. The elastic properties of these areas exactly correspond to them of partial molten mineral assemblages, in other words - partial molten rocks. This is a problem because the estimated in situ conditions - 140 GPa and 2900 degrees centigrade - should suppress melting. But there is also another problem. From high pressure experiments we have some knowledge about mineral phases stable under the conditions of the D''. The elastic properties of these minerals correspond quite good with seismological results - quite good but not sufficient. Looking in detail this is not surprising. Because of the very high pressures the critical experiments were carried out in diamond anvil cells and because of the necessarily small sample size mostly using single crystals, or at least mono-mineral polycrystals. But the whole mantle especially the ultradeep subducted plates consist of complex rocks of course. Above-mentioned we had noticed the elastic properties of fine-grained mineral mixtures do not equal the corresponding textured rock samples. If this is true under crustal conditions there is no doubt it is also

  19. Petrophysical properties and 3D block model of Buntsandstein Sandstones reservoir (Upper Rhine Graben)

    NASA Astrophysics Data System (ADS)

    Sébastien, Haffen; Yves, Géraud; Marc, Diraison; Chrystel, Dezayes

    2013-04-01

    Buntsandstein sandstones (upper Permian to middle Triassic), located in the Upper Rhine Graben, appear as an easy target for geothermal exploitation: this reservoir links more or less permeable argillaceous sandstones, intersected by many major faults, to the regional thermal anomaly. In this context, we propose a conceptual geological 3-D block model of the Buntsandstein reservoir which could be used as a guide for future regional geothermal exploration or exploitation. This block presents the Buntsandstein sandstones reservoir at depth with different sedimentary facies (braided rivers, playa lake and fluvio-aeolian), above the Palaeozoic Granit and below the Muschelkalk limestones, intersecting by faults oriented according regional major azimuths: (1) ≈N020°E, corresponding to Rhenish faults and (2) ≈N060°E (or ≈N130°E) corresponding to Hercynian reactivated faults. Petrophysical properties of the reservoir are both controlled by matrix and faults/fractures characteristics. (1) Matrix properties (porosity, permeability, thermal conductivity, Pwaves velocity) have been determined from petrophysical measurements performed on cores of 15 borehole, mainly on borehole EPS1 (Soultz-sous-Forêts, France), continuously cored through Buntsandstein; (2) from thermal gradient analyses based on thermal conductivity measurements on core samples and also from borehole temperature logs run in the same borehole. This last approach allows locating fluid flow and thus permeability at reservoir scale. The flow paths appear as a composite network controlled by 'sedimentary' permeability on one hand and by 'fracture' permeability on the other. Fracturing associated with major fault zones provide pathways for the upward flowing fluids to connect with stratigraphic levels characterized by high matrix permeability and no impermeable macroscopic layers. This is why the Playa Lake and Fluvio-aeolian marginal erg facies provide a reservoir connected to a deep hot fluid source

  20. The application of petrophysics to resolve fluid flow units and reservoir quality in the Upper Cretaceous Formations: Abu Sennan oil field, Egypt

    NASA Astrophysics Data System (ADS)

    Lala, Amir Maher Sayed; El-sayed, Nahla Abd El-Aziz

    2015-02-01

    Petrophysical flow unit concept can be used to resolve some of the key challenges faced in the characterization of hydrocarbon reservoirs. The present study deals with petrophysical evaluation of some physical properties of the Upper Cretaceous rock samples obtained from the Abu-Roash and the Bahariya Formations at southwest of Sennan oil field in the Western Desert of Egypt. The aim of this study was achieved through carrying out some petrophysical measurements of porosity, bulk density, permeability, mean hydraulic radius (Rh), irreducible water saturation, and radius of pore throat at mercury saturation of 35% in order to determine reservoir characteristics. In this study, the relationships obtained between the measured petrophysical properties such as porosity, permeability and pore throat flow unit types were established for 53 sandstone core samples obtained from two different stratigraphic units. Flow zone indicator (FZI) has been calculated to quantify the flow character of the Abu-Roash and Bahariya reservoir rocks based on empirically derived equations of robust correlation coefficients. The correlations among porosity, permeability, bulk density, mean hydraulic radius and pore throat flow properties reflect the most important reservoir behavior characteristics. The calculated multiple regression models indicate close correlation among petrophysical properties and Rh and R35%. The obtained models are able to predict Rh and R35% by using porosity and permeability, to map reservoir performance and predict the location of stratigraphic traps.

  1. Modeling the sorption kinetic of metsulfuron-methyl on Andisols and Ultisols volcanic ash-derived soils: kinetics parameters and solute transport mechanisms.

    PubMed

    Cáceres, Lizethly; Escudey, Mauricio; Fuentes, Edwar; Báez, María E

    2010-07-15

    Metsulfuron-methyl sorption kinetic was studied in Andisol and Ultisol soils in view of their distinctive physical and chemical properties: acidic pH and variable surface charge. Different kinetic models were applied to the experimental results. The pseudo-second-order model fitted sorption kinetics data better than the pseudo-first-order model. The rate constant and the initial rate constant values obtained through this model demonstrated the different behavior of metsulfuron-methyl in both kinds of soils, both parameters being the highest for Andisol. The application of Elovich equation, intraparticle diffusion model and a two-site nonequilibrium model (TSNE) allowed to conclude that: (i) the high organic matter content is the governing factor for Andisols where mass transfer across the boundary layer, and in a lesser degree, intraparticle diffusion were the two processes controlling sorption kinetic and (ii) the mineral composition was more relevant in Ultisols where rate was controlled almost exclusively by intraparticle diffusion into macropores and micropores. The slower sorption rate on Ultisols, the mechanism involved and the lower sorption capacity of this kind of soils must be taken into account to assess leaching behavior of this herbicide. PMID:20399011

  2. Petrophysical models of high velocity lower crust on the South Atlantic rifted margins: whence the asymmetry?

    NASA Astrophysics Data System (ADS)

    Trumbull, Robert B.; Franke, Dieter; Bauer, Klaus; Sobolev, Stephan V.

    2015-04-01

    Lower crustal bodies with high seismic velocity (Vp > 7km/s) underlie seaward-dipping reflector wedges on both margins of the South Atlantic, as on many other volcanic rifted margins worldwide. A comprehensive geophysical study of the South Atlantic margins by Becker et al. (Solid Earth, 5: 1011-1026, 2014) showed a strong asymmetry in the development of high-velocity lower crust (HVLC), with about 4 times larger volumes of HVLC on the African margin. That study also found interesting variations in the vertical position of HVLC relative to seaward-dipping reflectors which question a simple intrusive vs. extrusive relationship between these lower- and upper crustal features. The asymmetry of HVLC volumes on the conjugate margins is paradoxically exactly the opposite to that of surface lavas in the Paraná-Etendeka flood basalt province, which are much more voluminous on the South American margin. This contribution highlights the asymmetric features of magma distribution on the South Atlantic margins and explores their geodynamic significance. Petrophysical models of the HVLC are presented in the context of mantle melt generation, based on thickness-velocity (H-Vp) relations. These suggest that the greater volumes and average Vp values of HVLC on the African margin are due to active upwelling and high temperature, whereas passive upwelling under a thick lithospheric lid suppressed magma generation on the South American margin. The contrast in mantle upwelling rate and lithospheric thickness on the two margins predictably causes differential uplift, and this may help explain the greater accomodation space for surface lavas on the South American side although melt generation was strongest under the African margin.

  3. Petrofacies analysis - the petrophysical tool for geologic/engineering reservoir characterization

    SciTech Connect

    Watney, W.L.; Guy, W.J.; Gerlach, P.M.

    1997-08-01

    Petrofacies analysis is defined as the characterization and classification of pore types and fluid saturations as revealed by petrophysical measures of a reservoir. The word {open_quotes}petrofacies{close_quotes} makes an explicit link between petroleum engineers concerns with pore characteristics as arbiters of production performance, and the facies paradigm of geologists as a methodology for genetic understanding and prediction. In petrofacies analysis, the porosity and resistivity axes of the classical Pickett plot are used to map water saturation, bulk volume water, and estimated permeability, as well as capillary pressure information, where it is available. When data points are connected in order of depth within a reservoir, the characteristic patterns reflect reservoir rock character and its interplay with the hydrocarbon column. A third variable can be presented at each point on the crossplot by assigning a color scale that is based on other well logs, often gamma ray or photoelectric effect, or other derived variables. Contrasts between reservoir pore types and fluid saturations will be reflected in changing patterns on the crossplot and can help discriminate and characterize reservoir heterogeneity. Many hundreds of analyses of well logs facilitated by spreadsheet and object-oriented programming have provided the means to distinguish patterns typical of certain complex pore types for sandstones and carbonate reservoirs, occurrences of irreducible water saturation, and presence of transition zones. The result has been an improved means to evaluate potential production such as bypassed pay behind pipe and in old exploration holes, or to assess zonation and continuity of the reservoir. Petrofacies analysis is applied in this example to distinguishing flow units including discrimination of pore type as assessment of reservoir conformance and continuity. The analysis is facilitated through the use of color cross sections and cluster analysis.

  4. Petrophysical properties of saprolites from the Oak Ridge Integrated Field Research Challenge site, Tennessee

    SciTech Connect

    Revil, André; Skold, Magnus; Hubbard, Susan S.; Wu, Yuxin; Watson, David B.; Karaoulis, Marios

    2013-01-01

    At the Oak Ridge Integrated Field Research Challenge site, near Oak Ridge, Tennessee, the shallow saprolitic aquifer is contaminated by nitric acid, uranium, and metals originating from the former S3 settling ponds. To interpret low-frequency geophysical methods used to image contaminant plumes, we have characterized the petrophysical properties of three representative saprolite core samples. Their hydraulic conductivity ranges from to in agreement with field data. Complex conductivity measurements, in the frequency range of 1 mHz to 45 kHz, were performed with NaCl solutions with electrical conductivities in the range to , a range representative of field conditions. The electrical conductivity data were well reproduced with a simple linear conductivity model between the saprolite conductivity and the pore water conductivity. The conductivity plots were used to estimate the formation factor (the cementation exponent was about ) and the surface conductivity ( ). The magnitude of the surface conductivity depended on the degree of weathering and therefore on the amount of smectite and mixed layer (illite-smectite) clays present in the saprolite. The chargeability of the core samples was in the range of and is strongly dependent on the salinity. We also performed streaming potential measurements with the same pore fluid composition as that used for the complex conductivity measurements. We found an excess of movable electrical charges on the order of 100 to in agreement with previous investigations connecting the movable excess charge density to permeability. The zeta potential was in the range of to independent on the salinity. The electrical measurements were consistent with an average cation exchange capacity in the range of 1.4 to and a specific surface area on the order of 4000 to about 30,000 . Read More: http://library.seg.org/doi/abs/10.1190/geo2012-0176.1

  5. Petrophysical Properties of Twenty Drill Cores from the Los Azufres, Mexico, Geothermal Field

    SciTech Connect

    Iglesias, E.R.; Contreras L., E.; Garcia G., A.; Dominquez A., Bernardo

    1987-01-20

    For this study we selected 20 drill cores covering a wide range of depths (400-3000 m), from 15 wells, that provide a reasonable coverage of the field. Only andesite, the largely predominant rock type in the field, was included in this sample. We measured bulk density, grain (solids) density, effective porosity and (matrix) permeability on a considerable number of specimens taken from the cores; and inferred the corresponding total porosity and fraction of interconnected total porosity. We characterized the statistical distributions of the measured and inferred variables. The distributions of bulk density and grain density resulted approximately normal; the distributions of effective porosity, total porosity and fraction of total porosity turned out to be bimodal; the permeability distribution resulted highly skewed towards very small (1 mdarcy) values, though values as high as 400 mdarcies were measured. We also characterized the internal inhomogeneity of the cores by means of the ratio (standard deviation/mean) corresponding to the bulk density in each core (in average there are 9 specimens per core). The cores were found to present clearly discernible inhomogeneity; this quantitative characterization will help design new experimental work and interpret currently available and forthcoming results. We also found statistically significant linear correlations between total density and density of solids, effective porosity and total density, total porosity and total density, fraction of interconnected total porosity and the inverse of the effective porosity, total porosity and effective porosity; bulk density and total porosity also correlate with elevation. These results provide the first sizable and statistically detailed database available on petrophysical properties of the Los Azufres andesites. 1 tab., 16 figs., 4 refs.

  6. On the air-filled effective porosity parameter of Rogers and Nielson's (1991) bulk radon diffusion coefficient in unsaturated soils.

    PubMed

    Saâdi, Zakaria

    2014-05-01

    The radon exhalation rate at the earth's surface from soil or rock with radium as its source is the main mechanism behind the radon activity concentrations observed in both indoor and outdoor environments. During the last two decades, many subsurface radon transport models have used Rogers and Nielson's formula for modeling the unsaturated soil bulk radon diffusion coefficient. This formula uses an "air-filled effective porosity" to account for radon adsorption and radon dissolution in the groundwater. This formula is reviewed here, and its hypotheses are examined for accuracy in dealing with subsurface radon transport problems. The author shows its limitations by comparing one dimensional steady-state analytical solutions of the two-phase (air/water) transport equation (Fick's law) with Rogers and Nielson's formula. For radon diffusion-dominated transport, the calculated Rogers and Nielson's radon exhalation rate is shown to be unrealistic as it is independent of the values of the radon adsorption and groundwater dissolution coefficients. For convective and diffusive transport, radon exhalation rates calculated using Fick's law and this formula agree only for high values of gas-phase velocity and groundwater saturation. However, these conditions are not usually met in most shallow subsurface environments where radon migration takes place under low gas phase velocities and low water saturation. PMID:24670909

  7. Light intensity and production parameters of phytocenoses cultivated on soil-like substrate under controled environment conditions

    NASA Astrophysics Data System (ADS)

    Tikhomirov, A. A.; Ushakova, S. A.; Gribovskaya, I. A.; Tirranen, L. S.; Manukovsky, N. S.; Zolotukhin, I. G.; Karnachuk, R. A.; Gros, J.-B.; Lasseur, Ch.

    To increase the degree of closure of biological life support systems of a new generation, we used vermicomposting to involve inedible phytomass in the intra-system mass exchange. The resulting product was a soil-like substrate, which was quite suitable for growing plants (Manukovsky et al. 1996, 1997). However, the soil like substrate can be regarded as a candidate for inclusion in a system only after a comprehensive examination of its physical, chemical, and other characteristics. An important criterion is the ability of the soil-like substrate to supply the necessary mineral elements to the photosynthesizing component under the chosen cultivation conditions. Thus, the purpose of this work was to study the feasibility of enhancing the production activity of wheat and radish crops by varying the intensity of photosynthetically active radiation, without decreasing the harvest index. The increase of light intensity from 920 to 1150 μmol·m -2·s -1 decreased the intensity of apparent photosynthesis of the wheat crops and slightly increased the apparent photosynthesis of the radish crops The maximum total and grain productivity (kg/m -2) of the wheat crops was attained at the irradiance of 920 μmol·m -2·s -1. Light intensity of 1150 μmol·m -2·s -1 decreased the productivity of wheat plants and had no significant effect on the productivity of the radish crops (kg/m 2) as compared to 920 μmol·m -2·s -1. The qualitative and quantitative composition of microflora of the watering solution and substrate was determined by the condition of plants, developmental phase and light intensity. By the end of wheat growth under 1150 μmol·m -2·s -1 the numbers of bacteria of the coliform family and phytopathogenic bacteria in the watering solution and substrate were an order of magnitude larger than under other illumination conditions. The obtained data suggest that the cultivation of plants in a life support system on soil-like substrate from composts has a number of

  8. REDOX POTENTIAL AND OXYGEN DIFFUSION RATE AS PARAMETERS FOR MONITORING BIODEGRADATION OF SOME ORGANIC WASTES IN SOIL

    EPA Science Inventory

    The objective of the project was to evaluate control measurements that might be made at land treatment sites to determine the effectiveness of operation in the management of hazardous wastes. Initial studies were on measurement techniques available for parameters to serve as indi...

  9. Rock formation characterization for carbon dioxide geosequestration: 3D seismic amplitude and coherency anomalies, and seismic petrophysical facies classification, Wellington and Anson-Bates Fields, Kansas, USA

    NASA Astrophysics Data System (ADS)

    Ohl, Derek; Raef, Abdelmoneam

    2014-04-01

    Higher resolution rock formation characterization is of paramount priority, amid growing interest in injecting carbon dioxide, CO2, into subsurface rock formations of depeleting/depleted hydrocarbon reservoirs or saline aquifers in order to reduce emissions of greenhouse gases. In this paper, we present a case study for a Mississippian carbonate characterization integrating post-stack seismic attributes, well log porosities, and seismic petrophysical facies classification. We evaluated changes in petrophysical lithofacies and reveal structural facies-controls in the study area. Three cross-plot clusters in a plot of well log porosity and acoustic impedance corroborated a Neural Network petrophysical facies classification, which was based on training and validation utilizing three petrophysically-different wells and three volume seismic attributes, extracted from a time window including the wavelet of the reservoir-top reflection. Reworked lithofacies along small-throw faults has been revealed based on comparing coherency and seismic petrophysical facies. The main objective of this study is to put an emphasis on reservoir characterization that is both optimized for and subsequently benefiting from pilot tertiary CO2 carbon geosequestration in a depleting reservoir and also in the deeper saline aquifer of the Arbuckle Group, south central Kansas. The 3D seismic coherency attribute, we calculated from a window embracing the Mississippian top reflection event, indicated anomalous features that can be interpreted as a change in lithofacies or faulting effect. An Artificial Neural Network (ANN) lithofacies modeling has been used to better understand these subtle features, and also provide petrophysical classes, which will benefit flow-simulation modeling and/or time-lapse seismic monitoring feasibility analysis. This paper emphasizes the need of paying greater attention to small-scale features when embarking upon characterization of a reservoir or saline-aquifer for CO2

  10. Application of MASW method in studies on changes of soil elastic parameters over subsidence trough development during longwall exploitation

    NASA Astrophysics Data System (ADS)

    Mendecki, Maciej; Jochymczyk, Krzysztof

    2015-04-01

    The MASW method interpretation was applied to analyze 37 measurements which had been carried out to investigate spatial and temporal changes of elastic parameters in subsurface layers during extracting the coal bed. The seismic measurements were performed using the Terraloc apparatus containing 12 channels connected with 10 Hz geophones. 5 survey profiles were formed into a rosette with arms arranged relative about 45 degrees to each other. The research area was located in the Main Anticline, Upper Silesian Coal Basin, Southern Poland. The rosette was placed over the 201 longwall belonged to "Katowice - Kleofas" Coal Mine. Shallow geological structure consisted of subsurface soft layer (several meters) covered consolidated Carboniferous complex. Data interpretation were executed in winMASW software using the genetic algorithms to invert observed Rayleigh dispersion curve into S-wave velocity vertical profiles. In addition, the inversion allowed to determine parameters such as: density, thickness, shear modulus. The seismic study were carried out during total exploitation of the coal bed and for next 8 month after completion of mining works. Longer seismic observations than the mining works were due to a subsidence trough development over coal bed because the longwall face passage and subsidence trough development were shifted in time and it reached about 3 month. This time was needed to appear the subsidence trough on surface what was confirmed by leveling measurements. The longwall face had passed beneath the rosette in December, 1999 and in March, 2000 a sharp velocity drop on each profile was noticed. Next, a sudden velocity increase appeared in subsurface layer after the velocity drop. The changes of density and shear modulus was also remarked during the same period. At the beginning the sudden drop in velocity and other elastic parameters was associated with tension appeared on borders of subsidence trough. Then the geophysical profiles were in the compressive

  11. Integration of Petrophysical Methods and 3D Printing Technology to Replicate Reservoir Pore Systems

    NASA Astrophysics Data System (ADS)

    Ishutov, S.; Hasiuk, F.; Gray, J.; Harding, C.

    2014-12-01

    Pore-scale imaging and modeling are becoming routine geoscience techniques of reservoir analysis and simulation in oil and gas industry. Three-dimensional printing may facilitate the transformation of pore-space imagery into rock models, which can be compared to traditional laboratory methods and literature data. Although current methodologies for rapid rock modeling and printing obscure many details of grain geometry, computed tomography data is one route to refine pore networks and experimentally test hypotheses related to rock properties, such as porosity and permeability. This study uses three-dimensional printing as a novel way of interacting with x-ray computed tomography data from reservoir core plugs based on digital modeling of pore systems in coarse-grained sandstones and limestones. The advantages of using artificial rocks as a proxy are to better understand the contributions of pore system characteristics at various scales to petrophysical properties in oil and gas reservoirs. Pore radii of reservoir sandstones used in this study range from 1 to 100s of microns, whereas the pore radii for limestones vary from 0.01 to 10s of microns. The resolution of computed tomography imaging is ~10 microns; the resolution of 3D digital printing used in the study varies from 2.5 to 300 microns. For this technology to be useful, loss of pore network information must be minimized in the course of data acquisition, modeling, and production as well as verified against core-scale measurements. The ultimate goal of this study is to develop a reservoir rock "photocopier" that couples 3D scanning and modeling with 3D printing to reproduce a) petrophyscially accurate copies of reservoir pore systems and b) digitally modified pore systems for testing hypotheses about reservoir flow. By allowing us to build porous media with known properties (porosity, permeability, surface area), technology will also advance our understanding of the tools used to measure these quantities (e

  12. Estimating susceptibility and magnetization within the Earth's continental crust: Petrophysical and Satellite approaches

    NASA Astrophysics Data System (ADS)

    Purucker, M. E.; McEnroe, S. A.

    2014-12-01

    Magnetic models (Xchaos) made from Champ and Orsted data are used to place constraints on the average magnetic susceptibility and its variability in the continental crust. Estimates of magnetic crustal thickness are made in a two-step process. The first step uses a recent seismic model (Crust1.0) to estimate the thickness of crystalline crust above the Moho, modified in the Andes and the Himalayas to account for the non-magnetic lower crust there. The second step calculates the magnetic field expected from such a layer of crystalline rock assuming the magnetization is solely induced in the earth's main field by rock of constant magnetic susceptibility, and modifies the starting crustal thickness to bring it into agreement with the Xchaos model. This global model removes spherical harmonic degrees less than 15 to account for the core field mask. We restrict our attention to the continental crust, in particular to Australia, western North America, and Scandinavia. Petrophysical and petrological data from Scandinavian rocks that have been deep in the crust help place limits on susceptibility values. Our simulations use two susceptibilities, 0.02 and 0.04 SI. The mean crystalline crustal thickness from the seismic model is 42 and 37 km in western North America and Australia, respectively, and the modification with the magnetic data makes little change to the mean crustal thickness, irrespective of whether the susceptibility is 0.02 or 0.04 SI. However, the modification with the magnetic data does make a significant difference to the standard deviation of the crustal thickness, increasing it by a factor of two in the case of a susceptibility of 0.04, and by a factor of four in the case of a susceptibility of 0.02. The changes to the standard deviation of the crustal thickness are also evident in the Scandinavian data, but the mean crystalline crustal thickness of 45 km is significantly larger than that found from either magnetic model (33 and 30 km). The differences

  13. Geological and Petrophysical Characterization of the Ferron Sandstone for 3-D Simulation of a Fluvial-Deltaic Reservoir

    SciTech Connect

    M. Lee Allison

    1997-03-01

    The objective of this project is to develop a comprehensive, interdisciplinary, and quantitative characterization of a fluvial-deltaic reser v oir which will allow realistic inter-well and reservoir-scale modeling to be constructed for improved oil-field development in similiar reservoirs world-wide. The geological and petrophysical properties of the Cretaceous Ferron Sandstone in east-central Utah will be quantitatively determined . Both new and existing data will be integrated into a three-dimensional representation of spatial variations in porosity, storativity, and tensorial rock permeability at a scale appropriate for inter-well to regional-scale reservoir simulation. Results could improve reservoir management through proper infill and extension drilling strategies, reduction of economic risks, increased recovery from existing oil fields, and more reliable reserve calculations . Transfer of the project results to the petroleum industry is an integral component of the project. Four activities continued this quarter as part of the geological and petrophysical characterization of the fluvial-deltaic Ferron Sandstone in the Ivie Creek case-study area: (1) geostatistics, (2) field description of clinoform bounding surfaces, (3) reservoir modeling, and (4) technology transfer.

  14. An integrated petrophysical-geophysical approach for the characterization of a potential caprock-reservoir system for CO2 storage.

    NASA Astrophysics Data System (ADS)

    Fais, Silvana; Ligas, Paola; Cuccuru, Francesco; Casula, Giuseppe; Giovanna Bianchi, Maria; Maggio, Enrico; Plaisant, Alberto; Pettinau, Alberto

    2016-04-01

    The selection of a CO2 geologic storage site requires the choice of a study site suitable for the characterization in order to create a robust experimental database especially regarding the spatial petrophysical heterogeneities and elasto-mechanical properties of the rocks that make up a potential caprock-reservoir system. In our study the petrophysical and elasto-mechanical characterization began in a previously well drilled area in the northern part of the Sulcis coal basin (Nuraxi Figus area - SW Sardinia - Italy) where crucial geologic data were recovered from high-quality samples from stratigraphic wells and from mining galleries. The basin represents one of the most important Italian carbon reserves characterized by a great mining potential. In the study area, the Middle Eocene - Lower Oligocene Cixerri Fm. made up of terrigeneous continental rocks and the Upper Thanetian - Lower Ypresian Miliolitico Carbonate Complex in the Sulcis coal basin have been identified respectively as potential caprock and reservoir for CO2 storage. Petrophysical and geophysical investigations were carried out by a great number of laboratory tests on the core samples and in situ measurements on a mining gallery in order to characterize the potential caprock-reservoir system and to substantially reduce geologic uncertainty in the storage site characterization and in the geological and numerical modelling for the evaluation of CO2 storage capacity. In order to better define the spatial distribution of the petrophysical heterogeneity, the seismic responses from the caprock-reservoir system formations were also analysed and correlated with the petrophysical and elasto-mechanical properties In a second step of this work, we also analysed the tectonic stability of the study area by the integrated application of remote-sensing monitoring spatial geodetic techniques. In particular, the global positioning system (GPS) and interferometric synthetic aperture radar (inSAR) were considered

  15. Using visible and near-infrared diffuse reflectance spectroscopy for predicting soil properties based on regression with peaks parameters as derived from continuum-removed spectra

    NASA Astrophysics Data System (ADS)

    Vasat, Radim; Klement, Ales; Jaksik, Ondrej; Kodesova, Radka; Drabek, Ondrej; Boruvka, Lubos

    2014-05-01

    Visible and near-infrared diffuse reflectance spectroscopy (VNIR-DRS) provides a rapid and inexpensive tool for simultaneous prediction of a variety of soil properties. Usually, some sophisticated multivariate mathematical or statistical methods are employed in order to extract the required information from the raw spectra measurement. For this purpose especially the Partial least squares regression (PLSR) and Support vector machines (SVM) are the most frequently used. These methods generally benefit from the complexity with which the soil spectra are treated. But it is interesting that also techniques that focus only on a single spectral feature, such as a simple linear regression with selected continuum-removed spectra (CRS) characteristic (e.g. peak depth), can often provide competitive results. Therefore, we decided to enhance the potential of CRS taking into account all possible CRS peak parameters (area, width and depth) and develop a comprehensive methodology based on multiple linear regression approach. The eight considered soil properties were oxidizable carbon content (Cox), exchangeable (pHex) and active soil pH (pHa), particle and bulk density, CaCO3 content, crystalline and amorphous (Fed) and amorphous Fe (Feox) forms. In four cases (pHa, bulk density, Fed and Feox), of which two (Fed and Feox) were predicted reliably accurately (0.50 < R2cv < 0.80) and the other two (pHa and bulk density) only poorly (R2cv < 0.50), we obtained slightly better results than with PLSR and SVM. In one case (pHex) we achieved a significantly higher, although just reliable, accuracy (R2cv = 0.601) than with PLSR and SVM (R2cv = 0.448 and 0.442, resp.). But most interestingly, in the case of particle density, the presented approach outperformed the PLSR and SVM dramatically offering a fairly accurate prediction (R2cv = 0.827) against two failures (R2cv = 0.034 and 0.121 for PLSR and SVM, resp.). In last two cases (Cox and CaCO3) a slightly worse results were achieved then

  16. Soil thermal resistivity and thermal stability measuring instrument. Volume 2. Manual for operation and use of the thermal property analyzer and statistical weather analysis program to determine thermal design parameters. Final report

    SciTech Connect

    Boggs, S.A.; Radhakrishna, H.S.

    1981-11-01

    Numerous considerations influence the thermal design of an underground power cable, including the soil thermal resistivity, thermal diffusivity and thermal stability. Each of these properties is a function of soil moisture which is, in turn, a function of past weather, soil composition, and biological burden. The Neher-McGrath formalism has been widely used for thermal cable design. However, this formalism assumes knowledge of soil thermal properties (resistivity and diffusivity). For design purposes, these parameters should be treated statistically, since weather varies greatly from year-to-year. As well, soil thermal property surveys are normally required along the route to assess the thermal quality of the native soil. This project is intended to fill the gap between the need to carry out thermal design and the use of the Neher-McGrath formalism which is normally employed. This goal has been addressed through: development of instrumentation and methods of measuring soil thermal properties in situ and in the laboratory; recommendation of methods for conducting soil surveys along a proposed cable route and of assessing the thermal quality of soils; and development of a computerized method to treat soil thermal design parameters on a statistical basis using computerized weather records as supplied by the US Environmental Data Service. The use of the methods and instrumentation developed as a result of this contract should permit less conservative thermal design thereby improving the economics of underground transmission. As well, these techniques and instrumentation facilitate weather-dependent prediction of cable ampacity for installed cables, monitoring of backfill thermal stability, and many other new practices.

  17. The Impact of Carrot Enriched in Iodine through Soil Fertilization on Iodine Concentration and Selected Biochemical Parameters in Wistar Rats.

    PubMed

    Piątkowska, Ewa; Kopeć, Aneta; Bieżanowska-Kopeć, Renata; Pysz, Mirosław; Kapusta-Duch, Joanna; Koronowicz, Aneta Agnieszka; Smoleń, Sylwester; Skoczylas, Łukasz; Ledwożyw-Smoleń, Iwona; Rakoczy, Roksana; Maślak, Edyta

    2016-01-01

    Iodine is one of the trace elements which are essential for mammalian life. The major objective of iodine biofortification of plants is to obtain food rich in this trace element, which may increase its consumption by various populations. Additionally, it may reduce the risk of iodine deficiency diseases. In this research for the first time we have assessed the bioavailability of iodine from raw or cooked carrot biofortified with this trace element on iodine concentration in selected tissues and various biochemical parameters as well as mRNA expression of some genes involved in iodine metabolism in Wistar rats. Statistically, a significantly higher iodine level was determined in urine, faeces and selected tissues of rats fed a diet containing biofortified raw carrot as compared to a diet without iodine and a diet containing control cooked carrot. Biofortified raw carrot significantly increased triiodothyronine concentration as compared to animals from other experimental groups. The highest thyroid stimulating hormone level was determined in rats fed control cooked carrots. mRNA expression of selected genes was affected by different dietary treatment in rats' hearts. Biofortified raw and cooked carrot could be taken into account as a potential source of iodine in daily diets to prevent iodine deficiency in various populations. PMID:27043135

  18. The Impact of Carrot Enriched in Iodine through Soil Fertilization on Iodine Concentration and Selected Biochemical Parameters in Wistar Rats

    PubMed Central

    Piątkowska, Ewa; Kopeć, Aneta; Bieżanowska-Kopeć, Renata; Pysz, Mirosław; Kapusta-Duch, Joanna; Koronowicz, Aneta Agnieszka; Smoleń, Sylwester; Skoczylas, Łukasz; Ledwożyw-Smoleń, Iwona; Rakoczy, Roksana; Maślak, Edyta

    2016-01-01

    Iodine is one of the trace elements which are essential for mammalian life. The major objective of iodine biofortification of plants is to obtain food rich in this trace element, which may increase its consumption by various populations. Additionally, it may reduce the risk of iodine deficiency diseases. In this research for the first time we have assessed the bioavailability of iodine from raw or cooked carrot biofortified with this trace element on iodine concentration in selected tissues and various biochemical parameters as well as mRNA expression of some genes involved in iodine metabolism in Wistar rats. Statistically, a significantly higher iodine level was determined in urine, faeces and selected tissues of rats fed a diet containing biofortified raw carrot as compared to a diet without iodine and a diet containing control cooked carrot. Biofortified raw carrot significantly increased triiodothyronine concentration as compared to animals from other experimental groups. The highest thyroid stimulating hormone level was determined in rats fed control cooked carrots. mRNA expression of selected genes was affected by different dietary treatment in rats’ hearts. Biofortified raw and cooked carrot could be taken into account as a potential source of iodine in daily diets to prevent iodine deficiency in various populations. PMID:27043135

  19. Petrophysical Properties of Cody, Mowry, Shell Creek, and Thermopolis Shales, Bighorn Basin, Wyoming

    NASA Astrophysics Data System (ADS)

    Nelson, P. H.

    2013-12-01

    The petrophysical properties of four shale formations are documented from well-log responses in 23 wells in the Bighorn Basin in Wyoming. Depths of the examined shales range from 4,771 to 20,594 ft. The four formations are the Thermopolis Shale (T), the Shell Creek Shale (SC), the Mowry Shale (M), and the lower part of the Cody Shale (C), all of Cretaceous age. These four shales lie within a 4,000-ft, moderately overpressured, gas-rich vertical interval in which the sonic velocity of most rocks is less than that of an interpolated trendline representing a normal increase of velocity with depth. Sonic velocity, resistivity, neutron, caliper, and gamma-ray values were determined from well logs at discrete intervals in each of the four shales in 23 wells. Sonic velocity in all four shales increases with depth to a present-day depth of about 10,000 ft; below this depth, sonic velocity remains relatively unchanged. Velocity (V), resistivity (R), neutron porosity (N), and hole diameter (D) in the four shales vary such that: VM > VC > VSC > VT, RM > RC > RSC > RT, NT > NSC ≈ NC > NM, and DT > DC ≈ DSC > DM. These orderings can be partially understood on the basis of rock compositions. The Mowry Shale is highly siliceous and by inference comparatively low in clay content, resulting in high sonic velocity, high resistivity, low neutron porosity, and minimal borehole enlargement. The Thermopolis Shale, by contrast, is a black fissile shale with very little silt--its high clay content causes low velocity, low resistivity, high neutron response, and results in the greatest borehole enlargement. The properties of the Shell Creek and lower Cody Shales are intermediate to the Mowry and Thermopolis Shales. The sonic velocities of all four shales are less than that of an interpolated trendline that is tied to velocities in shales above and below the interval of moderate overpressure. The reduction in velocity varies among the four shales, such that the amount of offset (O) from

  20. Electromagnetic, seismic and petro-physical investigations of the lithosphere-asthenosphere boundary in central Tibet

    NASA Astrophysics Data System (ADS)

    Vozar, J.; Fullea, J.; Jones, A. G.; Agius, M. R.; Lebedev, S.

    2011-12-01

    beneath Central Lhasa terrane S-velocities are close to global-average values. We perform the integrated petro-physical modeling of MT and surface-wave data using the software package LitMod. The program facilitates definition of realistic temperature and pressure distributions within the upper mantle, and characterizes the mineral assemblages given bulk chemical compositions as well as water content. This allows us to firstly define a bulk geoelectric and seismic model of the upper mantle based on laboratory and xenolith data for the most relevant mantle minerals, and secondly to compute synthetic geophysical observables that are compared with measured data (i.e., MT responses, surface-wave dispersion curves, topography, and surface heat flow). Our preliminary results suggest an 80-120 km-thick, dry lithosphere in the central part of the Qiangtang Terrane. In the central Lhasa Terrane the data can be explained by a relatively warm 100-120 km-thick Tibetian lithosphere underlain by an 80-120-km-thick Indian lithosphere. The mid-lower crust in Lhasa shows strong seismic and electric anisotropy, with a predominant E-W oriented high velocity/conductivity axis.

  1. Structural and Petrophysical Characterization of Fault Zones in Shales: Example from the Tournemire Url (sw, France)

    NASA Astrophysics Data System (ADS)

    DICK, P.; Du Peloux de Saint Romain, A.; Moreno, E.; Homberg, C.; Renel, F.; Dauzères, A.; Wittebroodt, C.; Matray, J.

    2013-12-01

    The Tournemire Underground Research Laboratory (URL) operated by IRSN (French Institute for Radiological Protection and Nuclear Safety) is located on the western border of the Mesozoic sedimentary Causses Basin (SW France). The URL crosses a thick Toarcian shale formation (≈250 m) and is interbedded between two aquiferous limestone formations. In addition to the 250 m thick overlying limestones, the geotechnical and hydrogeological characteristics of this site exhibit similarities with those measured by the French National Agency for Radioactive Waste Management (Andra) in the Callovo-Oxfordian formation of Bure (Meuse/Haute Marne, France). The Tournemire site is marked by numerous minor shear bands that affect not only the shale formation but also the over- and underlying limestone units. Since analogous discontinuities in an underground deep geological repository could act as a preferential pathway for radionuclide migration, the Tournemire site appears as an ideal location to understand the internal and permeability structures of such clay-based faults. In this study, we investigate the structural and petrophysical variations observed in a 10-15 m thick, subvertical, strike-slip shear band. For this, eight fully cored and logged horizontal boreholes were drilled normal to the fault's direction. The internal architecture and permeability of the fault was revealed through a combination of different tools (AMS, SEM, XRD and helium pycnometer) used on samples, as well as optical, induction and neutron porosity logging used in boreholes. The analysis of core samples from the different boreholes indicates that the studied fault zone is divided into a fault core (gouge), surrounded by a damaged zone (e.g., kinematically related fracture sets, small faults, and veins). Porosity and hydraulic conductivity values are low in the undisturbed shale (respectively, 9% and 10-14 m.s-1) and increase progressively towards the fault core (respectively, 15-20% and 5.10-12 m.s-1

  2. Response of key soil parameters during compost-assisted phytostabilization in extremely acidic tailings: effect of plant species.

    PubMed

    Solís-Dominguez, Fernando A; White, Scott A; Hutter, Travis Borrillo; Amistadi, Mary Kay; Root, Robert A; Chorover, Jon; Maier, Raina M

    2012-01-17

    Phytostabilization of mine tailings acts to mitigate both eolian dispersion and water erosion events which can disseminate barren tailings over large distances. This technology uses plants to establish a vegetative cover to permanently immobilize contaminants in the rooting zone, often requiring addition of an amendment to assist plant growth. Here we report the results of a greenhouse study that evaluated the ability of six native plant species to grow in extremely acidic (pH ∼ 2.5) metalliferous (As, Pb, Zn: 2000-3000 mg kg(-1)) mine tailings from Iron King Mine Humboldt Smelter Superfund site when amended with a range of compost concentrations. Results revealed that three of the six plant species tested (buffalo grass, mesquite, and catclaw acacia) are good candidates for phytostabilization at an optimum level of 15% compost (w/w) amendment showing good growth and minimal shoot accumulation of metal(loid)s. A fourth candidate, quailbush, also met all criteria except for exceeding the domestic animal toxicity limit for shoot accumulation of zinc. A key finding of this study was that the plant species that grew most successfully on these tailings significantly influenced key tailings parameters; direct correlations between plant biomass and both increased tailings pH and neutrophilic heterotrophic bacterial counts were observed. We also observed decreased iron oxidizer counts and decreased bioavailability of metal(loid)s mainly as a result of compost amendment. Taken together, these results suggest that the phytostabilization process reduced tailings toxicity as well as the potential for metal(loid) mobilization. This study provides practical information on plant and tailings characteristics that is critically needed for successful implementation of assisted phytostabilization on acidic, metalliferous mine tailings sites. PMID:22191663

  3. Response of Key Soil Parameters During Compost-Assisted Phytostabilization in Extremely Acidic Tailings: Effect of Plant Species

    PubMed Central

    Solís-Dominguez, Fernando A.; White, Scott A.; Hutter, Travis Borrillo; Amistadi, Mary Kay; Root, Robert A.; Chorover, Jon; Maier, Raina M.

    2012-01-01

    Phytostabilization of mine tailings acts to mitigate both eolian dispersion and water erosion events which can disseminate barren tailings over large distances. This technology uses plants to establish a vegetative cover to permanently immobilize contaminants in the rooting zone, often requiring addition of an amendment to assist plant growth. Here we report the results of a greenhouse study that evaluated the ability of six native plant species to grow in extremely acidic (pH ~ 2.5) metalliferous (As, Pb, Zn: 2000–3000 mg kg−1) mine tailings from Iron King Mine Humboldt Smelter Superfund site when amended with a range of compost concentrations. Results revealed that three of the six plant species tested (buffalo grass, mesquite, and catclaw acacia) are good candidates for phytostabilization at an optimum level of 15% compost (w/w) amendment showing good growth and minimal shoot accumulation of metal(loid)s. A fourth candidate, quailbush, also met all criteria except for exceeding the domestic animal toxicity limit for shoot accumulation of zinc. A key finding of this study was that the plant species that grew most successfully on these tailings significantly influenced key tailings parameters; direct correlations between plant biomass and both increased tailings pH and neutrophilic heterotrophic bacterial counts were observed. We also observed decreased iron oxidizer counts and decreased bioavailability of metal(loid)s mainly as a result of compost amendment. Taken together, these results suggest that the phytostabilization process reduced tailings toxicity as well as the potential for metal(loid) mobilization. This study provides practical information on plant and tailings characteristics that is critically needed for successful implementation of assisted phytostabilization on acidic, metalliferous mine tailings sites. PMID:22191663

  4. Petrophysical laboratory invertigations of carbon dioxide storage in a subsurface saline aquifer in Ketzin/Germany within the scope of CO2SINK

    NASA Astrophysics Data System (ADS)

    Zemke, K.; Kummmerow, J.; Wandrey, M.; Co2SINK Group

    2009-04-01

    conditions over a period of several months. Before and after the CO2 exposure experiment cyclic measurements of physical properties were carried out on these cores in a mechanical testing system. After experimental runs of up to 3 months no significant changes in flow and petrophysical data were observed. [For the microbilogical studies see Wandrey et al., this volume.] To study the impact of fluid-rock interactions on petrophysical parameters, porosity and pore radii distribution have been investigated before and after the experiment by NMR relaxation and mercury-injection. NMR measurements on rock core plugs saturated with brine may return valuable information on the porous structure of the rock core. The distribution of NMR-T2 values (CPMG) reflects the pore sizes within the rock core. NMR pore size is a derivative of the ratio pore surface/volume. The mercury injection pore size is an area-equivalent diameter of the throats connecting the pore system. Most of the tested samples show in the NMR measurements a slightly increasing porosity and a higher part of large pores. The mercury measurements and thin- section for microstructural characterisation after the CO2 exposure will be done at a later date.

  5. Variations of the petrophysical properties of rocks with increasing hydrocarbons content and their implications at larger scale: insights from the Majella reservoir (Italy)

    NASA Astrophysics Data System (ADS)

    Trippetta, Fabio; Ruggieri, Roberta; Lipparini, Lorenzo

    2016-04-01

    Crustal processes such as deformations or faulting are strictly related to the petrophysical properties of involved rocks. These properties depend on mineral composition, fabric, pores and any secondary features such as cracks or infilling material that may have been introduced during the whole diagenetic and tectonic history of the rock. In this work we investigate the role of hydrocarbons (HC) in changing the petrophysical properties of rock by merging laboratory experiments, well data and static models focusing on the carbonate-bearing Majella reservoir. This reservoir represent an interesting analogue for the several oil fields discovered in the subsurface in the region, allowing a comparison of a wide range of geological and geophysical data at different scale. The investigated lithology is made of high porosity ramp calcarenites, structurally slightly affected by a superimposed fracture system and displaced by few major normal faults, with some minor strike-slip movements. Sets of rock specimens were selected in the field and in particular two groups were investigated: 1. clean rocks (without oil) and 2. HC bearing rocks (with different saturations). For both groups, density, porosity, P and S wave velocity, permeability and elastic moduli measurements at increasing confining pressure were conducted on cylindrical specimens at the HP-HT Laboratory of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) in Rome, Italy. For clean samples at ambient pressure, laboratory porosity varies from 10 % up to 26 % and P wave velocity (Vp) spans from 4,1 km/s to 4,9 km/s and a very good correlation between Vp, Vs and porosity is observed. The P wave velocity at 100 MPa of confining pressure, ranges between 4,5 km/s and 5,2 km/s with a pressure independent Vp/Vs ratio of about 1,9. The presence of HC within the samples affects both Vp and Vs. In particular velocities increase with the presence of hydrocarbons proportionally respect to the amount of the filled

  6. Foliated vs. dilatant fault rocks in deeply buried arkosic turbidites: characterisation of their distinct petrophysical properties. The case of the Gres d'Annot, French Alps

    NASA Astrophysics Data System (ADS)

    Cavailhes, Thibault; Labaume, Pierre; Sizun, Jean-Pierre; Soliva, Roger; Gout, Claude; Chauvet, Alain; Buatier, Martine; Potdevin, Jean-Luc; Charpentier, Delphine; Trave, Anna

    2013-04-01

    Fault zones are major discontinuities in sedimentary basins. Understanding their role on fluid migrations is an essential issue to (i) characterise the mechanisms and kinematics of deformation and (ii) to determine the parameters which control the distribution of energetic or mineral resources. This work applies to faulting under a temperature range of 200-250°C, corresponding to that of deeply buried reservoirs as well as potentially seismogenic fault zones. The studied faults are normal faults affecting the "Grès d'Annot" Formation, a Priabonian-Rupelian siliclastic turbidite succession of the Alpine foreland basin. They are located in two distinct areas: the Moutière-Restefond area in the eastern part of the basin and the Estrop area in the western part. Vitrinite reflectance outside fault zones indicates maximal temperatures of 240-260°C at Moutière-Restefond and 170-200°C at Estrop, i.e. burial depths around 8 km and 6 km, respectively, assuming a mean geothermal gradient of 30°C/km. Burial was due to underthrusting below the Embrunais-Ubaye Alpine nappes, the difference in burial between the two areas traducing the westward taper of the nappes front. The studied faults affect alternating arkosic sandstone beds and pelite layers with offsets from centimeters to decameters. Two types of core zones are recognized: (1) the foliated core zones of the Moutière-Restefond area, where deformation dominated by pressure solution and synkinematic phyllosilicate neoformation resulted in a foliated fabric, and (2) the core zones of the Estrop area, characterized by dilatant quartz-mineralized veins and breccia. Fault and host rock petrophysical properties were measured on drill plugs, using the water porosity technique and nitrogen permeability technique under 2 Mpa of confining pressure. In the Moutière-Restefond fault zones, plug axes were oriented in three orthogonal directions corresponding to the main deformation axes (X, Y, Z) of the foliated arkose to

  7. Atlas of soil reflectance properties

    NASA Technical Reports Server (NTRS)

    Stoner, E. R.; Baumgardner, M. F.; Biehl, L. L.; Robinson, B. F.

    1979-01-01

    A compendium of soil spectral reflectance curves together with soil test results and site information is presented in an abbreviated manner listing those soil properties most important in influencing soil reflectance. Results are presented for 251 soils from 39 states and Brazil. A narrative key describes relationships between soil parameters and reflectance curves. All soils are classified according to the U.S. soil taxonomy and soil series name for ease of identification.

  8. Petrologic and petrophysical evaluation of the Dallas Center Structure, Iowa, for compressed air energy storage in the Mount Simon Sandstone.

    SciTech Connect

    Heath, Jason E.; Bauer, Stephen J.; Broome, Scott Thomas; Dewers, Thomas A.; Rodriguez, Mark Andrew

    2013-03-01

    The Iowa Stored Energy Plant Agency selected a geologic structure at Dallas Center, Iowa, for evaluation of subsurface compressed air energy storage. The site was rejected due to lower-than-expected and heterogeneous permeability of the target reservoir, lower-than-desired porosity, and small reservoir volume. In an initial feasibility study, permeability and porosity distributions of flow units for the nearby Redfield gas storage field were applied as analogue values for numerical modeling of the Dallas Center Structure. These reservoir data, coupled with an optimistic reservoir volume, produced favorable results. However, it was determined that the Dallas Center Structure cannot be simplified to four zones of high, uniform permeabilities. Updated modeling using field and core data for the site provided unfavorable results for air fill-up. This report presents Sandia National Laboratories' petrologic and petrophysical analysis of the Dallas Center Structure that aids in understanding why the site was not suitable for gas storage.

  9. Effect of texture on petrophysical properties of dolomite: Evidence from the Cambrian-Ordovician of southeastern Missouri

    SciTech Connect

    Woody, R.E.; Gregg, J.M.; Koederitz, L.F.

    1996-01-01

    Two basic textural types of dolomite exist: (1) planar dolomite, which forms in both shallow and burial diagenetic environments; and (2) nonplanar dolomite, which develops at temperatures in excess of 50{degrees}C in the burial environment by dolomitization of limestone or neomorphic recrystallization of preexisting dolomite. Variation in dolomite texture is the result of variation in the diagenetic history of the rock unit. Cambrian-Ordovician dolomites were collected from core and outcrop throughout southeastern Missouri. Effective porosity and permeability were determined using helium porosimetry and gas permeability. Total porosity and texture type were determined from thin-section analysis. Pore throat geometry was evaluated using mercury capillary pressure curves and scanning electron microscope (SEM) examination of pore casts. Two porosity-permeability populations exist for planar dolomite: (1) planar-e (euhedral) dolomite, where permeability strongly varies with porosity; and (2) planar-s (subhedral) dolomite, where permeability is lower than in planar-e dolomite and does not increase as rapidly with increasing porosity. In planar-e dolomite, capillary pressure data and SEM pore cast analysis indicate uniform pore throat sizes and well-interconnected pore systems. Uniform throat sizes and well-connected pore systems do not exist in planar-s dolomite. This most likely is due to continued cementation during diagenesis. The petrophysical properties of dolomite petroleum reservoirs and aquifers vary depending on the petrographic texture of the dolomite. Understanding diagenetic history, and crystal textures that may result because of various diagenetic conditions, can be a predictor of petrophysical properties of dolomite reservoirs.

  10. Calculation of thermal conductivity, thermal diffusivity and specific heat capacity of sedimentary rocks using petrophysical well logs

    NASA Astrophysics Data System (ADS)

    Fuchs, Sven; Balling, Niels; Förster, Andrea

    2015-12-01

    In this study, equations are developed that predict for synthetic sedimentary rocks (clastics, carbonates and evapourates) thermal properties comprising thermal conductivity, specific heat capacity and thermal diffusivity. The rock groups are composed of mineral assemblages with variable contents of 15 major rock-forming minerals and porosities of 0-30 per cent. Petrophysical properties and their well-logging-tool-characteristic readings were assigned to these rock-forming minerals and to pore-filling fluids. Relationships are explored between each thermal property and other petrophysical properties (density, sonic interval transit time, hydrogen index, volume fraction of shale and photoelectric absorption index) using multivariate statistics. The application of these relations allows computing continuous borehole profiles for each rock thermal property. The uncertainties in the prediction of each property vary depending on the selected well-log combination. Best prediction is in the range of 2-8 per cent for the specific heat capacity, of 5-10 per cent for the thermal conductivity, and of 8-15 for the thermal diffusivity, respectively. Well-log derived thermal conductivity is validated by laboratory data measured on cores from deep boreholes of the Danish Basin, the North German Basin, and the Molasse Basin. Additional validation of thermal conductivity was performed by comparing predicted and measured temperature logs. The maximum deviation between these logs is <3 °C. The thermal-conductivity calculation allowed an evaluation of the depth range in which the palaeoclimatic effect on the subsurface temperature field can be observed in the North German Basin. This effect reduces the surface heat-flow density by 25 mW m-2.

  11. Petrophysics of Lower Silurian sandstones and integration with the tectonic-stratigraphic framework, Appalachian basin, United States

    USGS Publications Warehouse

    Castle, J.W.; Byrnes, A.P.

    2005-01-01

    Petrophysical properties were determined for six facies in Lower Silurian sandstones of the Appalachian basin: fluvial, estuarine, upper shoreface, lower shoreface, tidal channel, and tidal flat. Fluvial sandstones have the highest permeability for a given porosity and exhibit a wide range of porosity (2-18%) and permeability (0.002-450 md). With a transition-zone thickness of only 1-6 m (3-20 ft), fluvial sandstones with permeability greater than 5 md have irreducible water saturation (Siw) less than 20%, typical of many gas reservoirs. Upper shoreface sandstones exhibit good reservoir properties with high porosity (10-21%), high permeability (3-250 md), and low S iw (<20%). Lower shoreface sandstones, which are finer grained, have lower porosity (4-12%), lower permeability (0.0007-4 md), thicker transition zones (6-180 m [20-600 ft]), and higher S iw. In the tidal-channel, tidal-flat, and estuarine facies, low porosity (average < 6%), low permeability (average < 0.02 md), and small pore throats result in large transition zones (30-200 m; 100-650 ft) and high water saturations. The most favorable reservoir petrophysical properties and the best estimated production from the Lower Silurian sandstones are associated with fluvial and upper shoreface facies of incised-valley fills, which we interpret to have formed predominantly in areas of structural recesses that evolved from promontories along a collisional margin during the Taconic orogeny. Although the total thickness of the sandstone may not be as great in these areas, reservoir quality is better than in adjacent structural salients, which is attributed to higher energy depositional processes and shallower maximum burial depth in the recesses than in the salients. Copyright ??2005. The American Association of Petroleum Geologists. All rights reserved.

  12. Geological and Petrophysical Characterization of the Ferron Sandstone for 3-D Simulation of a Fluvial-Deltaic Reservoir.

    SciTech Connect

    Allison, M.L.

    1997-07-01

    The objective of this project is to develop a comprehensive, interdisciplinary, and quantitative characterization of a fluvial- deltaic reservoir which will allow realistic inter-well and reservoir-scale modeling to be constructed for improved oil-field development in similar reservoirs world-wide. The geological and petrophysical properties of the Cretaceous Ferron Sandstone in east-central Utah will be quantitatively determined. Both new and existing data will be integrated into a three-dimensional representation of spatial variations in porosity, storativity, and tensorial rock permeability at a scale appropriate for inter-well to regional-scale reservoir simulation. Results could improve reservoir management through proper infill and extension drilling strategies, reduction of economic risks, increased recovery from existing oil fields, and more reliable reserve calculations. Transfer of the project results to the petroleum industry is an integral component of the project. Two activities continued this quarter as part of the geological and petrophysical characterization of the fluvial-deltaic Ferron Sandstone: (1) evaluation of the Ivie Creek case-study area and (2) technology transfer. The Ivie Creek case-study evaluation work during the quarter focused on the two parasequence sets, the Kf-1 and Kf-2, in the lower Ferron Sandstone. This work included: (1) clinoform characterization, (2) parasequence characterization from elevation and isopach maps, and (3) three-dimensional facies modeling. Scaled photomosaic panels from the Ivie Creek amphitheater (south-facing outcrop belt) and Quitchupah Canyon (Fig. 1) provide a deterministic framework for two apparent-dip cross sections. These panels along with other photomosaic coverage and data from five drill holes, ten stratigraphic sections, and 22 permeability transacts (Fig. 1), acquired during two field seasons, provided the necessary information for this geologic evaluation and creation of the models to be used

  13. Effects of variations in hydrogeological parameters on water-table mounding in sandy loam and loamy sand soils beneath stormwater infiltration basins

    NASA Astrophysics Data System (ADS)

    Thompson, Anita; Nimmer, Mike; Misra, Debasmita

    2010-03-01

    The two-dimensional variably-saturated numerical model HYDRUS-2D, previously calibrated to recharge events from an infiltration basin, was used to predict water-table mounding under hypothetical basin design scenarios, and the primary factors that affect water-table mounding were evaluated. Infiltration basins are often utilized in urban environments to recharge stormwater to the aquifer. As a result of localized recharge beneath these basins, mound formation may reduce the thickness of the unsaturated zone available to filter pollutants and may reduce the infiltration rate of the basin. Understanding the effects of various physical factors on water-table mound formation is important for infiltration basin siting. For sandy loam and loamy sand subsurface materials, mound heights increased as the thickness of both the unsaturated and saturated zones decreased. Mound heights increased as the initial soil moisture, basin size and ponding depth increased. A thin sedimentation layer on the basin floor delayed mound formation, but only slightly decreased the maximum mound height. This analysis could be used in future selection of infiltration basin locations; however, the analysis is limited to conditions that represent only a select range of basin design conditions and parameters typical of a glacial till environment in Wisconsin, USA.

  14. Probability density of spatially distributed soil moisture inferred from crosshole georadar traveltime measurements

    NASA Astrophysics Data System (ADS)

    Linde, N.; Vrugt, J. A.

    2009-04-01

    Geophysical models are increasingly used in hydrological simulations and inversions, where they are typically treated as an artificial data source with known uncorrelated "data errors". The model appraisal problem in classical deterministic linear and non-linear inversion approaches based on linearization is often addressed by calculating model resolution and model covariance matrices. These measures offer only a limited potential to assign a more appropriate "data covariance matrix" for future hydrological applications, simply because the regularization operators used to construct a stable inverse solution bear a strong imprint on such estimates and because the non-linearity of the geophysical inverse problem is not explored. We present a parallelized Markov Chain Monte Carlo (MCMC) scheme to efficiently derive the posterior spatially distributed radar slowness and water content between boreholes given first-arrival traveltimes. This method is called DiffeRential Evolution Adaptive Metropolis (DREAM_ZS) with snooker updater and sampling from past states. Our inverse scheme does not impose any smoothness on the final solution, and uses uniform prior ranges of the parameters. The posterior distribution of radar slowness is converted into spatially distributed soil moisture values using a petrophysical relationship. To benchmark the performance of DREAM_ZS, we first apply our inverse method to a synthetic two-dimensional infiltration experiment using 9421 traveltimes contaminated with Gaussian errors and 80 different model parameters, corresponding to a model discretization of 0.3 m × 0.3 m. After this, the method is applied to field data acquired in the vadose zone during snowmelt. This work demonstrates that fully non-linear stochastic inversion can be applied with few limiting assumptions to a range of common two-dimensional tomographic geophysical problems. The main advantage of DREAM_ZS is that it provides a full view of the posterior distribution of spatially

  15. [Effects of soil progressive drought during the flowering and boll-forming stage on gas exchange parameters and chlorophyll fluorescence characteristics of the subtending leaf to cotton boll].

    PubMed

    Liu, Zhao-wei; Zhang, Pan; Wang, Rui; Kuai, Jie; Li, Lei; Wang, You-hua; Zhou, Zhi-guo

    2014-12-01

    To investigate the dynamic changes and response mechanisms of gas exchange parameters and fluorescence indices of the subtending leaf to cotton boll under soil progressive drought stress, pot experiments of the hybrid cotton No. 3 were conducted with soil relative water content (SRWC) (75 +/- 5)% as control group, SRWC (60 +/- 5)% and SRWC (45 +/- 5)% as experimental groups dealt with progressive drought for 50 days. Results showed that, the net photosynthetic rate (Pn), stomatal conductance (g(s)) and leaf intercellular CO2 concentration (Ci) decreased while Ls increased under SRWC (60 +/- 5)% for 0-21 days. Furthermore, there was no significant change in chlorophyll fluorescence indices. This indicated that stomatal limitation was the main reason for the reduction of photosynthesis of cotton. In addition, when drought for 21-49 days under SRWC (60 +/- 5)%, Pn kept decreasing, while Ci began to increase and Ls began to decrease. Potential photochemical efficiency (Fv/Fm), quantum yield of photo system II (phi(PSI)) and photochemical quenching coefficient (q(P)) reduced significantly, but non-photochemical quenching coefficient (NPQ) first rose then decreased. Thus, nonstomatal limitation was the main reason why the photosynthesis of cotton reduced. Photosynthetic organization and photosynthetic enzyme system were destroyed, boll setting intensity reduced and the number of boll and yield reduced significantly. Drought for 0-14 days under SRWC (45 +/- 5)% treatment led to sharp decrease in Pn, g(s) and Ci, whereas Ls obviously increased. There was no significant change in Fv/Fm, phi(PSII), q(P), indicating stomatal limitation was the main reason why the photosynthesis of cotton reduced. Pn decreased slowly, while Ci began to rise and Ls began to decline under SRWC (45 +/- 5)% treatment for 14-49 days. Fv/Fm, phi(PSII), q(P) decreased while NPQ rose first then declined, which indicated that nonstomatal limitation worked to reduce the cotton photosynthetic performance

  16. Soil spectral characterization

    NASA Technical Reports Server (NTRS)

    Stoner, E. R.; Baumgardner, M. F.

    1981-01-01

    The spectral characterization of soils is discussed with particular reference to the bidirectional reflectance factor as a quantitative measure of soil spectral properties, the role of soil color, soil parameters affecting soil reflectance, and field characteristics of soil reflectance. Comparisons between laboratory-measured soil spectra and Landsat MSS data have shown good agreement, especially in discriminating relative drainage conditions and organic matter levels in unvegetated soils. The capacity to measure both visible and infrared soil reflectance provides information on other soil characteristics and makes it possible to predict soil response to different management conditions. Field and laboratory soil spectral characterization helps define the extent to which intrinsic spectral information is available from soils as a consequence of their composition and field characteristics.

  17. Effective porosity and density of carbonate rocks (Maynardville Limestone and Copper Ridge Dolomite) within Bear Creek Valley on the Oak Ridge Reservation based on modern petrophysical techniques

    SciTech Connect

    Dorsch, J.

    1997-02-01

    The purpose of this study is to provide quantitative data on effective porosity of carbonate rock from the Maynardville Limestone and Copper Ridge Dolomite within Bear Creek Valley based on modern petrophysical techniques. The data will be useful for groundwater-flow and contaminant-flow modeling in the vicinity of the Y-12 Plant on the Oak Ridge Reservation (ORR). Furthermore, the data provides needed information on the amount of interconnected pore space potentially available for operation of matrix diffusion as a transport process within the fractured carbonate rock. A second aspect of this study is to compare effective porosity data based on modern petrophysical techniques to effective porosity data determined earlier by Goldstrand et al. (1995) with a different technique. An added bonus of the study is quantitative data on the bulk density and grain density of dolostone and limestone of the Maynardville Limestone and Copper Ridge Dolomite which might find use for geophysical modeling on the ORR.

  18. The early diagenetic and PETROphysical behaviour of recent cold-water CARbonate mounds in Deep Environments (PETROCARDE)

    NASA Astrophysics Data System (ADS)

    Foubert, Anneleen; Pirlet, Hans; Thierens, Mieke; de Mol, Ben; Henriet, Jean-Pierre; Swennen, Rudy

    2010-05-01

    Sub-recent cold-water carbonate mounds localized in deeper slope settings on the Atlantic continental margins cannot be any longer neglected in the study of carbonate systems. They clearly play a major role in the dynamics of mixed siliciclastic-carbonate and/or carbonate-dominated continental slopes. Carbonate accumulation rates of cold-water carbonate mounds are about 4 to 12 % of the carbonate accumulation rates of tropical shallow-water reefs but exceed the carbonate accumulation rates of their slope settings by a factor of 4 to 12 (Titschack et al., 2009). These findings emphasize the importance of these carbonate factories as carbonate niches on the continental margins. The primary environmental architecture of such carbonate bodies is well-characterized. However, despite proven evidences of early diagenesis overprinting the primary environmental record (e.g. aragonite dissolution) (Foubert & Henriet, 2009), the extent of early diagenetic and biogeochemical processes shaping the petrophysical nature of mounds is until now not yet fully understood. Understanding (1) the functioning of a carbonate mound as biogeochemical reactor triggering early diagenetic processes and (2) the impact of early diagenesis on the petrophysical behaviour of a carbonate mound in space and through time are necessary (vital) for the reliable prediction of potential late diagenetic processes. Approaching the fossil carbonate mound record, through a profound study of recent carbonate bodies is innovative and will help to better understand processes observed in the fossil mound world (such as cementation, brecciation, fracturing, etc…). In this study, the 155-m high Challenger mound (Porcupine Seabight, SW of Ireland), drilled during IODP Expedition 307 aboard the R/V Joides Resolution (Foubert & Henriet, 2009), and mounds from the Gulf of Cadiz (Moroccan margin) will be discussed in terms of early diagenetic processes and petrophysical behaviour. Early differential diagenesis

  19. Facies and petrophysical modelling of a thick lower cretaceous tsunami deposit in E Spain: Up-scaling from sample to outcrop scales

    NASA Astrophysics Data System (ADS)

    Veloso, Fernanda M. L.; Liesa, Carlos L.; Soria, Ana R.; Meléndez, Nieves; Frykman, Peter

    2016-08-01

    The tsunami deposit (up to 3 m thick) of the Cretaceous Camarillas Formation in the Galve sub-basin (eastern Spain) is characterized by a large lateral extent (35 km2) and facies uniformity, consisting in fine to coarse subarkosic-arkosic sandstones. At the scale of outcrop observation, different lithofacies were distinguished and related to sedimentation processes. Sand facies distribution conditioned the facies heterogeneity at both mesoscopic or outcrop scales (10- 1-101 m scale) and sample scale (10- 3-10- 2 m). The sample features were up-scaled to that of a facies model using probability functions and variograms as well as to outcrop-scale data (geometry and size) of facies distribution, and it showed a good correlation with the facies distribution at the outcrop. Porosity is strongly correlated to permeability and the pairs of porosity and permeability values fall into the global hydraulic element (GHEs) 5, so that they can be up-scaled into reservoir models in terms of hydraulic properties. From data analysis, no apparent link between sand sorting and porosity and permeability values was observed. The petrophysical models, which were independent of facies models, were up-scaled taking into account the porosity and permeability values from sample data and the statistical analysis of their distribution along the outcrop. The permeability model was carried out as a function of porosity by applying a linear relation, which simplified the modelling process and discarded permeability uncertainties linked to facies distribution in the deposit. In spite of different source data, the petrophysical models show a distribution of lower and higher values that resembles the facies model. Consequently, our modelling results clearly suggest the link of facies type and their grain size distributions with the petrophysical properties into the deposit. Consistency between facies and petrophysical models and outcrop-scale observations make it possible to extrapolate to other

  20. TRANSLATING AVAILABLE BASIC SOIL DATA INTO MISSING SOIL HYDRAULIC CHARACTERISTICS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil hydraulic pedotransfer functions transfer simple-to-measure soil survey information into soil hydraulic characteristics, that are otherwise costly to measure. Examples are presented of different equations describing hydraulic characteristics and of pedotransfer functions used to predict paramet...

  1. X-ray CT analyses, models and numerical simulations: a comparison with petrophysical analyses in an experimental CO2 study

    NASA Astrophysics Data System (ADS)

    Henkel, Steven; Pudlo, Dieter; Enzmann, Frieder; Reitenbach, Viktor; Albrecht, Daniel; Ganzer, Leonhard; Gaupp, Reinhard

    2016-06-01

    An essential part of the collaborative research project H2STORE (hydrogen to store), which is funded by the German government, was a comparison of various analytical methods for characterizing reservoir sandstones from different stratigraphic units. In this context Permian, Triassic and Tertiary reservoir sandstones were analysed. Rock core materials, provided by RWE Gasspeicher GmbH (Dortmund, Germany), GDF Suez E&P Deutschland GmbH (Lingen, Germany), E.ON Gas Storage GmbH (Essen, Germany) and RAG Rohöl-Aufsuchungs Aktiengesellschaft (Vienna, Austria), were processed by different laboratory techniques; thin sections were prepared, rock fragments were crushed and cubes of 1 cm edge length and plugs 3 to 5 cm in length with a diameter of about 2.5 cm were sawn from macroscopic homogeneous cores. With this prepared sample material, polarized light microscopy and scanning electron microscopy, coupled with image analyses, specific surface area measurements (after Brunauer, Emmet and Teller, 1938; BET), He-porosity and N2-permeability measurements and high-resolution microcomputer tomography (μ-CT), which were used for numerical simulations, were applied. All these methods were practised on most of the same sample material, before and on selected Permian sandstones also after static CO2 experiments under reservoir conditions. A major concern in comparing the results of these methods is an appraisal of the reliability of the given porosity, permeability and mineral-specific reactive (inner) surface area data. The CO2 experiments modified the petrophysical as well as the mineralogical/geochemical rock properties. These changes are detectable by all applied analytical methods. Nevertheless, a major outcome of the high-resolution μ-CT analyses and following numerical data simulations was that quite similar data sets and data interpretations were maintained by the different petrophysical standard methods. Moreover, the μ-CT analyses are not only time saving, but also

  2. Estimating effective roughness parameters of the L-MEB model for soil moisture retrieval using passive microwave observations from SMAPVEX12

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although there have been 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 modeling the observed microwave signal. This paper focuses on the estimation of effective sur...

  3. Macro and micro nutrient uptake parameters and use efficiency in cacao genotypes influenced by deficient to excess levels of soil K

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cacao (Theobroma cacao L.) is an important economic crop for many of the tropical countries. Adequate levels of soil K are essential for good growth and achieving high cocoa bean yields. Soils under cacao invariably have low levels of plant available K to support good cacao growth. Growth chamber ex...

  4. Evaluation of chemical parameters and ecotoxicity of a soil developed on gossan following application of polyacrylates and growth of Spergularia purpurea.

    PubMed

    Santos, Erika S; Abreu, Maria Manuela; de Varennes, Amarilis; Macías, Felipe; Leitão, Sara; Cerejeira, Maria José

    2013-09-01

    The aim of this study was to evaluate the chemical characteristics and ecotoxicity of a mine soil developed on gossan materials and amended with hydrophilic polyacrylate polymers after a growth cycle of Spergularia purpurea. Different acute bioassays (Daphnia magna immobilization; microalgae growth inhibition; germination and growth of lettuce and oat) were carried out with simulated leachates, pore water and soil samples. The germination and growth of native shrubs (Cistus ladanifer and Lavandula sampaioana) were also evaluated in the lysimeters where S. purpurea had grown. The soil had high total concentrations (g/kg) of Al (3.50-8.60), As (2.55-2.73), Cu (0.13-0.91) and Pb (4.48-6.16). However, the percentages of elements in aqueous extracts (simulating leachates, pore water, and the conditions of the rhizosphere soil) were small when compared to their total soil concentrations (less than 9% except for Na in leachates). Growth of S. purpurea and other natural colonization of plant species (Poaceae, Fabaceae and Asteraceae families) improved chemical characteristics but the application of the polyacrylate polymers contributed to a further improvement of soil quality. However, this was not sufficient to ensure the growth of a large number of shrubs despite a great germination rate. Among the several species used on the ecotoxicological assessment, the D. magna test was the only bioassay that showed a clear toxicity of soil leachates, suggesting the importance of using several ecotoxicological tests to assess the environmental risk of soil contamination and its rehabilitation. Although the studied soil can be considered contaminated taking into account the total soil concentrations of Al, As, Cu and Pb, the low concentrations of the same chemical elements in extractable solutions, that simulated the fractions really available for organisms, did not demonstrate a substantial toxic effects in the organisms and, consequently, negative impact on the environment. PMID

  5. Impact of raw pig slurry and pig farming practices on physicochemical parameters and on atmospheric N2O and CH 4 emissions of tropical soils, Uvéa Island (South Pacific).

    PubMed

    Roth, E; Gunkel-Grillon, P; Joly, L; Thomas, X; Decarpenterie, T; Mappe-Fogaing, I; Laporte-Magoni, C; Dumelié, N; Durry, G

    2014-09-01

    Emissions of CH4 and N2O related to private pig farming under a tropical climate in Uvéa Island were studied in this paper. Physicochemical soil parameters such as nitrate, nitrite, ammonium, Kjeldahl nitrogen, total organic carbon, pH and moisture were measured. Gaseous soil emissions as well as physicochemical parameters were compared in two private pig farming strategies encountered on this island on two different soils (calcareous and ferralitic) in order to determine the best pig farming management: in small concrete pens or in large land pens. Ammonium levels were higher in control areas while nitrate and nitrite levels were higher in soils with pig slurry inputs, indicating that nitrification was the predominant process related to N2O emissions. Nitrate contents in soils near concrete pens were important (≥ 55 μg N/g) and can thus be a threat for the groundwater. For both pig farming strategies, N2O and CH4 fluxes can reach high levels up to 1 mg N/m(2)/h and 1 mg C/m(2)/h, respectively. CH4 emissions near concrete pens were very high (≥ 10.4 mg C/m(2)/h). Former land pens converted into agricultural land recover low N2O emission rates (≤ 0.03 mg N/m(2)/h), and methane uptake dominates. N2O emissions were related to nitrate content whereas CH4 emissions were found to be moisture dependent. As a result relating to the physicochemical parameters as well as to the gaseous emissions, we demonstrate that pig farming in large land pens is the best strategy for sustainable family pig breeding in Uvéa Islands and therefore in similar small tropical islands. PMID:24862486

  6. Architectural characteristics and petrophysical properties evolution of a strike-slip fault zone in a fractured porous carbonate reservoir

    NASA Astrophysics Data System (ADS)

    Jeanne, Pierre; Guglielmi, Yves; Lamarche, Juliette; Cappa, Frédéric; Marié, Lionel

    2012-11-01

    This paper describes the structural, petrophysical and hydromechanical properties relationships between a small fault zone and the porous layered carbonate series which host it. In a gallery located at 250-m depth, the deformation of a 22-m thick section of layered carbonates-, affected by a strike slip-fault have been characterized by means of structural (Q-value), acoustic velocities (Vp), porosity and uniaxial compressive strength (σc) measurements conducted in situ at the meter scale, and on laboratory samples at the infra-centimeter scale. A clear influence of the layers initial properties on fault architecture and properties evolution is underlined. In the porous layers with a low σc, there is an important accommodation of the deformation by micro-mechanisms resulting in a progressive decrease in the porosity toward the fault core. In the low-porosity layers with a high σc, deformations are accommodated toward the fault core by: an increase in the fracture porosity, in the micro-cracks porosity, and by displacements along pre-existing fractures resulting from a joint roughness decrease. The fault zone appears as relatively stiff and low permeable zones intercalated with low stiffness and high fracture permeability zones that extend one to tens of meters from the fault following the initial properties contrasts and geometry of the sedimentary layers.

  7. [Distribution of potentially nitrogen-fixing bacteria and its relationship with physicochemical parameters in soils with three vegetation types in the southern Colombian Amazon region].

    PubMed

    Mantilla-Paredes, Andrea J; Cardona, Gladys I; Peña-Venegas, Clara P; Murcia, Uriel; Rodríguez, Mariana; Zambrano, Maria M

    2009-12-01

    Potentially nitrogen-fixing microaerobic and aerobic bacteria were isolated from several Colombian Amazon soils (forest, pastures and chagras) and two landscapes (floodable and non floodable areas). The abundance and distribution of bacteria were evaluated, as well as their relationship with soil physical and chemical characteristics. Landscape had a direct influence on the abundance of the microaerobic bacteria, with higher numbers in forest and pasture soils in non-floodable zones. The aerobic isolates (N=51) were grouped into 19 morphologies, with the highest numbers found in forest soil in floodable zones. A higher number of aerobic morphologies was shared among forest sites (Nonmetric Multidimensional Scaling and Analysis of Similarity p<0.05), and 40% of the distribution was explained by lime percentage and Al concentration. PMID:20073324

  8. Petrophysical properties of carbonate rocks: example from the cretaceous Jandaira Formation, Potiguar basin - Brazil

    NASA Astrophysics Data System (ADS)

    Nogueira, Francisco; Soares, José; Bezerra, Francisco; Cavalcanti, Bruno; Cazarin, Caroline

    2015-04-01

    Carbonate sediments are prone to rapid and pervasive diagenetic alterations that change the mineralogy and pore structure within carbonate units. In particular, cementation and dissolution processes continuously modify the pore structure to create or destroy porosity. In extreme cases these modifications can completely change the mineralogy from calcite to dolomite, in the properties of rock for soil (Caliche), or reverse the pore distribution whereby original grains are dissolved to produce pores as the original pore space is filled with cement to form the rock. These processes are common in fractured carbonate units. All these modifications alter the elastic properties of the rock and, therefore, the sonic velocity. This study presents the result of relationship among diagenesis, porosity, grain density, and sonic velocity, in limestones, dolomites and caliche samples from the Jandaíra Formation, Potiguar basin, Brasil. This stratigraphic unit have been subjected to fracturing since the late Cretaceous. The rock and soil samples were collected in outcrops, prepared as plugs, and analyzed at ambient temperature. The porosity and grain density analysis were performed under ambient pressure, while elastic properties analyses were conducted with samples under confining pressure between 5 and 40 MPa. The result is a wide range of sonic velocity in carbonates, in which compressional-wave velocity (VP) ranges from 3507 to 6119 m/s and shear-wave velocity (VS) range from 2114 to 3451 m/s. The ratio VS1/VS2 indicate a level of anisotropy equal to 2%, without any clear relationship with porosity. The elastics properties are affected by rock alteration process or by modification of mineral composition, due to the presence of clay minerals and organic matter, The porosity and grain density values range from 3.2 to 21.5%, and 2.7 to 2.8 (g/cm3), respectively. The grain density analysis in the carbonate rocks indicate the existence of two groups: the first group of calcareous

  9. Electrical properties of soils

    NASA Astrophysics Data System (ADS)

    Pozdnyakova, Larisa A.

    In this study, thorough analysis is conducted for soil electrical properties, i.e. electrical resistivity, conductivity, and potential. Soil electrical properties are the parameters of natural and artificially created electrical fields in soils and influenced by distribution of mobile electrical charges, mostly inorganic ions, In soils. Distributions of electrical charges and properties in various soil profiles were shown to be results of the soil-forming processes. Soil properties influencing the density of mobile electrical charges were found to be exponentially related with electrical resistivity and potential based on Boltzmann's law of statistical thermodynamics. Relationships were developed between electrical properties and other soil physical and chemical properties, such as texture, stone content, bulk density, water content, cation exchange capacity, salinity, humus content, and base saturation measured in-situ and in soil samples. Geophysical methods of vertical electrical sounding, four-electrode probe, non-contact electromagnetic profiling, and self-potential were modified for measuring soil electrical properties and tested in different soil studies. The proposed methods are extremely efficient, reliable, and non-disturbing. Compared with conventional methods of soil analysis, the electrical geophysical methods allowed evaluating groundwater table, salt content, depth and thickness of soil horizons, Polluted or disturbed layers in soil profiles, and stone content with an estimation error <10%. The methods provide extensive data on spatial and temporal variations in soil electrical properties, which relate to the distributions of other essential soil properties. The electrical properties were incorporated with the data from conventional soil analyses to enhance the estimation of a number of soil physical and chemical properties and to assist soil survey. The study shows various applications of the modified geophysical methods in soil physics, soil

  10. [Evaluation of parameters of radionuclide transition from soil particles and plant components of the upper layer of turf to cow's milk under pasture conditions].

    PubMed

    Averin, V S; Kalinichenko, S A; Nenashev, R A; Tsurankov, E N

    2002-01-01

    An experiment was conducted on feeding lactating cows with soil and turf additives contaminated with both 137Cs and 90Sr of the Chernobyl origin. The radionuclides transfer coefficients (%) in the food chain were for soil additives: for 137Cs--0.02 +/- 0.006, for 90Sr--0.01 +/- 0.002; for turf additives: for 137Cs--0.02 +/- 0.005, for 90Sr--0.06 +/- 0.035. Regarding 90Sr, there is no significant tendency to higher transfer rate for the radionuclide from turf component compared to that for soil component. A contribution of soil component as well as turf component of soil was evaluated as an additional source of milk contamination while grazing cattle. It was concluded that the contribution is not pronounced at the remedial period after the accident (approximately 3% from total activity consumed with ration) and it can be rejected in cattle breeding practice. The results achieved can be used for prediction of radionuclides concentrations in milk produce in cattle breeding under industrial contamination of agricultural lands. PMID:12395781

  11. Facies distribution, depositional environment, and petrophysical features of the Sharawra Formation, Old Qusaiba Village, Central Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Abbas, Muhammad Asif; Kaminski, Michael; Umran Dogan, A.

    2016-04-01

    The Silurian Sharawra Formation has great importance as it rests over the richest source rock of the Qusaiba Formation in central Saudi Arabia. The Sharawra Formation has four members including Jarish, Khanafriyah, Nayyal, and Zubliyat. The formation mainly consists of sandstone and siltstone with subordinate shale sequences. The lack of published research on this formation requires fundamental studies that can lay the foundation for future research. Three outcrops were selected from the Old Qusaiba Village in Central Saudi Arabia for field observations, petrographical and petrophysical study. Thin section study has been aided by quantitative mineralogical characterization using scanning electron microscopy - energy dispersive spectroscopy and powder x-ray diffraction (XRD) for both minerals, cements, and clay minerals (detrital and authigenic). The outcrops were logged in detail and nine different lithofacies have been identified. The thin section study has revealed the Sharawra Formation to be mainly subarkosic, while the mica content increases near to its contact with the Qusaiba Formation. The XRD data has also revealed a prominent change in mineralogy with inclusion of minerals like phlogopite and microcline with depths. Field observations delineated a prominent thinning of strata as lithofacies correlation clearly shows the thinning of strata in the southwestern direction. The absence of outcrop exposures further supports the idea of southwestern thinning of strata. This is mainly attributed to local erosion and the presence of thicker shale interbeds in the southeastern section, which was probably subjected to more intense erosion than the northwestern one. The Sharawra Formation rests conformably over the thick transgressive shale sequence, deposited during the post glacial depositional cycle. The lowermost massive sandstone bed of the Sharawra Formation represents the beginning of the regressive period. The shale interbeds in the lower part are evidence of

  12. Silicon-mediated changes on some physiological and enzymatic parameters symptomatic of oxidative stress in barley grown in sodic-B toxic soil.

    PubMed

    Gunes, Aydin; Inal, Ali; Bagci, Esra G; Coban, Sencan

    2007-06-01

    The effect of silicon (Si) on the growth, sodium (Na), chloride (Cl), boron (B) concentrations, lipid peroxidation (MDA), membrane permeability (MP), lypoxygenase activity (LOX), proline (PRO) and H(2)O(2) accumulation, and the activities of major antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT and ascorbate peroxidase, APX) of barley grown in original sodic-B toxic soil were investigated. Si applied to the sodic-B toxic soil at 70, 140 and 280 mg kg(-1) levels significantly increased Si concentrations of the plants and counteracted the deleterious effects of sodicity (Na ions) and B on shoot growth. Membrane permeability and the concentrations of H(2)O(2) and MDA increased, while PRO concentration decreased in plants grown in sodic-B toxic soil without Si. LOX activity was increased by applied Si. Compared with control plants, the activities of SOD and CAT were decreased, but APX was increased by applied Si levels. PMID:17070965

  13. Effects of depositional facies and diagenesis on calculating petrophysical properties for wireline logs in Permian carbonate reservoirs of west Texas

    SciTech Connect

    Holtz, M.H.; Major, R.P. )

    1994-03-01

    The complex interplay between depositional facies and diagenesis in carbonate rocks presents numerous problems for calculating petrophysical properties from wireline logs. If carbonate reservoirs are divided into flow units of similar depositional and diagenetic textures, empirical equations that apply specifically to that geologically identified flow unit can be developed to accurately measure porosity and water saturation. In Guadalupian and Leonardian reservoirs, carbonate mudstones deposited in subtidal marine settings are predominantly dolomite, although they contain some shale. The shale in these rocks can be detected with gamma-ray logs and empirical equations for calculation of porosity from log must include a gamma-ray component to compensate for the presence of shale. Because porosity in these rocks is dominantly intercrystalline, capillary pressure characteristics are predictable and saturations can be calculated with the Archie equation. Subtidal carbonate packstones and grainstones are composed of dolomite, anhydrite, and gypsum. The matrix acoustic transit times of these three minerals are similar, and acoustic logs are the best tool for measuring porosity. Neutron logs are the least accurate porosity tools if gypsum is present. Photo-electric density logs can distinguish gypsum from anhydrite. Because porosity in these rocks is dominantly interparticle and/or moldic, dual porosity cementation exponent corrections are needed to calculate saturations with the Archie equation, and capillary pressure saturation relationships are variable. Carbonates deposited in tidal-flat environments are generally composed of dolomite, sulfate minerals, and quartz silt, requiring a full suite of open-hole logs to make reliable porosity measurements. Diagenesis influences reservoir mineralogy and pore types. A common style of burial diagenesis in Guadalupian and Leonardian reservoirs is hydration of anhydrite to gypsum and leaching of sulfate cement and dolomite matrix.

  14. Atrazine dissipation in s-Triazine-adapted and Non-adapted soil from Coloroado and Mississippi: Implications of enhanced degradation on atrazine fate and transport parameters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Modelers and regulatory agencies typically use default atrazine half-life values of 60 to 120 d to predict the herbicide’s transport; however, if atrazine persistence is reduced in soils exhibiting enhanced degradation, but modelers continue to use historic atrazine persistence estimates, then accur...

  15. Parameter Sets for Upper and Lower Bounds on SOIL-TO-INDOOR-AIR CONTAMINANT ATTENUATION PREDICTED BY THE JOHNSON AND ETTINGER VAPOR INTRUSION MODEL

    EPA Science Inventory

    Migration of volatile chemicals from the subsurface into overlying buildings is known as vapor intrusion (VI). Under certain circumstances, people living in homes above contaminated soil or ground water may be exposed to harmful levels of these vapors. A popular VI screening-le...

  16. Laboratory study of mechanical and petrophysical properties of both intact and naturally fractured shale samples from the Tournemire Underground Research Laboratory

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Understanding the mechanical and physical properties of fractured shales is of major importance in many fields such as the study of cap rock integrity or targets for radioactive waste disposal. In particular, relationships between fluid transport properties and textural anisotropy are critical. Therefore, these relations need to be investigated on real fault samples. This study in collaboration with IRSN and Total deals with the mechanical and petrophysical characterization of core samples from the Tournemire Underground Research Laboratory in Southern France. Three boreholes crossing a major fault at different angles have been investigated. The cores retrieved were carefully sampled and give access to the three major areas defining the fault zone: 1) the intact zone, 2) the damaged zone and 3) the fault core. The goal of the study is to perform several petrophysical measurements on the same specimens sampled at different distances from the fault core. These include multidirectional measurements of P and S waves under preserved humidity conditions, magnetic susceptibility measurements and pore size distribution characterization through the BET gas adsorption method. Some preliminary results show an evolution of the anisotropy with the distance to the fault core (anisotropy reversal). The boreholes that were sampled were drilled to perform hydromechanical in situ testing, therefore one of our objectives is also to compare the hydromechanical properties obtained in the mesoscale experiments in situ to the petrophysical measurements in the lab. Mechanical tests were also performed on intact samples in order to understand the mechanisms of deformation of the studied shale, depending on the orientation of the maximal applied stress with respect to bedding.

  17. Geological and petrophysical characterization of the Ferron Sandstone for 3-D simulation of a fluvial-deltaic reservoir. Quarterly progress report, July 1--September 30, 1995

    SciTech Connect

    Allison, M.L.

    1995-10-30

    The objective of this project is to develop a comprehensive, interdisciplinary, and quantitative characterization of a fluvial-deltaic reservoir which will allow realistic inter-well and reservoir-scale modeling to be constructed for improved oil-field development in similar reservoirs world-wide. The geological and petrophysical properties of the Cretaceous Ferron Sandstone in east-central Utah will be quantitatively determined. Both new and existing data will be integrated into a three-dimensional representation of spatial variations in porosity, storativity, and tensorial rock permeability at a scale appropriate for inter-well to regional-scale reservoir simulation. Results could improve reservoir management through proper infill and extension drilling strategies, reduction of economic risks, increased recovery from existing oil fields, and more reliable reserve calculations. Transfer of the project results to the petroleum industry is an integral component of the project. Technical progress this quarter is divided into regional stratigraphy, case studies, stochastic modeling and fluid-flow simulation, and technology transfer activities. The regional stratigraphy of the Ferron Sandstone outcrop belt is being described and interpreted. Detailed geological and petrophysical characterization of the primary reservoir lithofacies typically found in a fluvial-dominated deltaic reservoir, is continuing at selected case-study areas. Interpretations of lithofacies, bounding surfaces, and other geologic information are being combined with permeability measurements from closely spaced traverses and from drill-hole cores (existing and two drilled during the quarter). Petrophysical and statistical analyses are being incorporated with the geological characterization to develop a three-dimensional model of the reservoirs through fluid-flow simulation.

  18. Influence of soil moisture on soil respiration

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  19. Structure and function in soil hydrology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Structure of soil and soil cover is the major control of soil functioning, being in turn controlled with multiple feedbacks. Existing methods and parameters to characterize soil and soil cover structure are scale-dependent. The purpose of this talk to suggest that the effect of structure on soil h...

  20. Structure and Function in Soil Hydrology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Structure of soil and soil cover is the major control of soil hydrologic functioning, being in turn controlled with multiple feedbacks. Existing methods and parameters to characterize both soil/soil cover structure and soil hydrologic functioning are scale-dependent. The purpose of this presentation...

  1. Evolution of Pedostructure Parameters Under Tillage Practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The pedostructure (PS) concept is a physically-based method of soil characterization that defines a soil based on its structure and the relationship between structure and soil water behavior. There are 15 unique pedostructure parameters that define the macropore and micropore soil water behavior fo...

  2. Determination of petrophysical properties of geothermal reservoirs in southern Denmark by integrating information from well logs and reflection seismic data

    NASA Astrophysics Data System (ADS)

    Rasmussen, Marie L.; Balling, Niels; Bording, Thue S.; Clausen, Ole R.

    2013-04-01

    As part of the efforts to reduce CO2 emission, geothermal energy is an important source for future energy production in Denmark, and several research programs deal with this specific subject e.g. "The geothermal energy potential in Denmark - reservoir properties, temperature distribution and models for utilization", funded by the Danish Strategic Research Council and "GEOPOWER" which is part of an EU INTERREG-program focused on southern Denmark and northernmost Germany. For geothermal energy to be economically sustainable porous and permeable rocks needs to be present at a depth where the temperature is sufficiently high. Utilization of geothermal energy in Denmark and plans for the future are concentrated on low enthalpy basin reservoirs for district heating. Major modeling studies are carried out to establish the temperature distribution in the Danish subsurface. This project deals with the reservoir properties. The geothermal reservoir exploited so far in the southern Danish area is restricted to the lower Jurassic-Triassic Gassum Formation. The Gassum Formation is a shallow marine to fluvial deposit composed of sandy to silty sediments, occasionally with coal layers, i.e. a lateral and stratigraphically heterogeneous rock. This formation is encountered only in deep hydrocarbon exploration wells and in wells of the Sønderborg Geothermal plant. Due to the very low number and low density of wells and the limited rock material recovered during drilling, the knowledge of lateral variations of reservoir properties in terms of porosity, permeability and thickness, is limited and so far unsatisfactorily mapped. The main risks in the utilization of geothermal energy from the subsurface of Denmark are therefore regional, as well as local, variations in the production potential of warm water, whereas the temperature can be assessed fairly precisely due to the thermal models available. Here we use petrophysical wells logs available from hydrocarbon exploration wells for

  3. Integration of Sedimentology,Petrophysics and Statistics for Characterizing the Reservoir Heterogeneity of the Late Ordovician Sarah Formation, Central Saudi Arabia

    NASA Astrophysics Data System (ADS)

    El-Deek, Islam; Abdullatif, Osman; Korvin, Gabor; Al-Ramadan, Khalid

    2014-05-01

    The first glaciogenic event in the Arabian Peninsula is represented by the Late Ordovician Sarah Formation. Sarah Formation is outcropping in areas of central and northern Arabia bordering the Arabian Shield, while it occupies several sub-basinal areas in the subsurface. The glacio-fluvial Sarah Formation is considered as an important tight gas reservoir target. This study uses the outcrop analog of the Sarah Formation to characterize the reservoir heterogeneity of the paleovalleys based on sedimentological, petrophysical, and statistical approaches. Facies types and architectural elements were identified within several paleovalleys of the Sarah Formation. The study indicated variability in texture, composition, sandstone type, facies, geometry and architecture at outcrop scale. Outcrop relationships also showed vertical and lateral facies change with other Paleozoic formations. The integration of field and laboratory data helped identifying the heterogeneity within Sarah paleovalleys. The reservoir quality trends in the Sarah Formation show variations that might be due to the controls of facies, depositional environments, and paleogeography. Three measures of heterogeneity were applied on the petrophysical data for various paleovalleys of the Sarah Formation. Those measures are: the coefficient of variation, Dykstra-Parsons, and Lorenz coefficients.The coefficient of variation values indicate extremely heterogeneous distribution. Dykstra-Parsons coefficient values suggest very to extremely heterogeneous reservoirs. Lorenz coefficients show good correlation with Dykstra-Parsons coefficient for Sarah paleovalleys. The studied heterogeneity measures indicate that Sarah paleovalleys represent very to extremely heterogeneous reservoirs.

  4. Geological and petrophysical characterization of the Ferron Sandstone for 3-D simulation of a fluvial-deltaic reservoir. Technical progress report, April 1--June 30, 1995

    SciTech Connect

    Allison, M.L.

    1995-07-28

    The objective of this project is to develop a comprehensive, interdisciplinary, and quantitative characterization of a fluvial-deltaic reservoir which will allow realistic inter-well and reservoir-scale modeling to be constructed for improved oil-field development in similar reservoirs world-wide. The geological and petrophysical properties of the Cretaceous Ferron Sandstone in east-central Utah will be quantitatively determined. Both new and existing data will be integrated into a three-dimensional representation of spatial variations in porosity, storativity, and tensorial rock permeability at a scale appropriate for inter-well to regional-scale reservoir simulation. Results could improve reservoir management through proper infill and extension drilling strategies, reduction of economic risks, increased recovery from existing oil fields, and more reliable reserve calculations. Technical progress this quarter is divided into regional stratigraphy, case studies, stochastic modeling and fluid-flow simulation, and technology transfer activities. The regional stratigraphy of the Ferron Sandstone outcrop belt from Last Chance Creek to Ferron Creek is being described and interpreted. Photomosaics and a database of existing surface and subsurface data are being used to determine the extent and depositional environment of each parasequence, and the nature of the contacts with adjacent rocks or flow units. For the second field season, detailed geological and petrophysical characterization of the primary reservoir lithofacies typically found in a fluvial-dominated deltaic reservoir, is continuing at selected case-study areas.

  5. Geological and petrophysical characterization of the Ferron Sandstone for 3-D simulation of a fluvial-deltaic reservoir. Technical progress report, October 1--December 1997

    SciTech Connect

    Allison, M.L.

    1998-01-01

    The objective of this project is to develop a comprehensive, interdisciplinary, and quantitative characterization of a fluvial-deltaic reservoir which will allow realistic inter-well and reservoir-scale modeling to be constructed for improved oil-field development in similar reservoirs world-wide. The geological and petrophysical properties of the Cretaceous Ferron Sandstone in east-central Utah will be quantitatively determined. Both new and existing data will be integrated into a three-dimensional representation of spatial variations in porosity, storativity, and tensorial rock permeability at a scale appropriate for inter-well to regional-scale reservoir simulation. Results could improve reservoir management through proper infill and extension drilling strategies, reduction of economic risks, increased recovery from existing oil fields, and more reliable reserve calculations. Transfer of the project results to the petroleum industry is an integral component of the project. Two activities continued this quarter as part of the geological and petrophysical characterization of the fluvial-deltaic Ferron Sandstone and are described within: (1) regional stratigraphic interpretation and (2) technology transfer.

  6. Geological and petrophysical characterization of the Ferron Sandstone for 3-D simulation of a fluvial-deltaic reservoir. Quarterly report, July 1--September 30, 1997

    SciTech Connect

    Allison, M.L.

    1997-11-01

    The objective of this project is to develop a comprehensive, interdisciplinary, and quantitative characterization of a fluvial-deltaic reservoir which will allow realistic inter-well and reservoir-scale modeling to be constructed for improved oil-field development in similar reservoirs world-wide. The geological and petrophysical properties of the Cretaceous Ferron Sandstone in east-central Utah will be quantitatively determined. Both new and existing data will be integrated into a three-dimensional representation of spatial variations in porosity, storativity, and tensorial rock permeability at a scale appropriate for inter-well to regional-scale reservoir simulation. Results could improve reservoir management through proper infill and extension drilling strategies, reduction of economic risks, increased recovery from existing oil fields, and more reliable reserve calculations. Two activities continued this quarter as part of the geological and petrophysical characterization of the fluvial-deltaic Ferron Sandstone: (1) evaluation of the Ivie Creek and Willow Springs Wash case-study areas and (2) technology transfer.

  7. Geological and petrophysical characterization of the Ferron Sandstone for 3-D simulation of a fluvial-deltaic reservoir. Quarterly report, April 1--June 30, 1998

    SciTech Connect

    Chidsey, T.C. Jr.

    1998-07-01

    The objective of this project is to develop a comprehensive, interdisciplinary, and quantitative characterization of a fluvial-deltaic reservoir which will allow realistic inter-well and reservoir-scale modeling to be constructed for improved oil-field development in similar reservoirs world-wide. The geological and petrophysical properties of the Cretaceous Ferron Sandstone in east-central Utah will be quantitatively determined. Both new and existing data will be integrated into a three-dimensional representation of spatial variations in porosity, storativity, and tensorial rock permeability at a scale appropriate for inter-well to regional-scale reservoir simulation. Results could improve reservoir management through proper infill and extension drilling strategies, reduction of economic risks, increased recovery from existing oil fields, and more reliable reserve calculations. Transfer of the project results to the petroleum industry is an integral component of the project. Two activities continued this quarter as part of the geological and petrophysical characterization of the fluvial-deltaic Ferron Sandstone: (1) preparation of the project final report and (2) technology transfer.

  8. Hardrock Elastic Physical Properties: Birch's Seismic Parameter Revisited

    NASA Astrophysics Data System (ADS)

    Wu, M.; Milkereit, B.

    2014-12-01

    Identifying rock composition and properties is imperative in a variety of fields including geotechnical engineering, mining, and petroleum exploration, in order to accurately make any petrophysical calculations. Density is, in particular, an important parameter that allows us to differentiate between lithologies and estimate or calculate other petrophysical properties. It is well established that compressional and shear wave velocities of common crystalline rocks increase with increasing densities (i.e. the Birch and Nafe-Drake relationships). Conventional empirical relations do not take into account S-wave velocity. Physical properties of Fe-oxides and massive sulfides, however, differ significantly from the empirical velocity-density relationships. Currently, acquiring in-situ density data is challenging and problematic, and therefore, developing an approximation for density based on seismic wave velocity and elastic moduli would be beneficial. With the goal of finding other possible or better relationships between density and the elastic moduli, a database of density, P-wave velocity, S-wave velocity, bulk modulus, shear modulus, Young's modulus, and Poisson's ratio was compiled based on a multitude of lab samples. The database is comprised of isotropic, non-porous metamorphic rock. Multi-parameter cross plots of the various elastic parameters have been analyzed in order to find a suitable parameter combination that reduces high density outliers. As expected, the P-wave velocity to S-wave velocity ratios show no correlation with density. However, Birch's seismic parameter, along with the bulk modulus, shows promise in providing a link between observed compressional and shear wave velocities and rock densities, including massive sulfides and Fe-oxides.