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Sample records for variable charge soils

  1. VARIABLE CHARGE SOILS: MINERALOGY AND CHEMISTRY

    Energy Technology Data Exchange (ETDEWEB)

    Van Ranst, Eric; Qafoku, Nikolla; Noble, Andrew; Xu, Ren-Kou

    2016-09-19

    Soils rich in particles with amphoteric surface properties in the Oxisols, Ultisols, Alfisols, Spodosols and Andisols orders (1) are considered to be variable charge soils (2) (Table 1). The term “variable charge” is used to describe organic and inorganic soil constituents with reactive surface groups whose charge varies with pH and ionic concentration and composition of the soil solution. Such groups are the surface carboxyl, phenolic and amino functional groups of organic materials in soils, and surface hydroxyl groups of Fe and Al oxides, allophane and imogolite. The hydroxyl surface groups are also present on edges of some phyllosilicate minerals such as kaolinite, mica, and hydroxyl-interlayered vermiculite. The variable charge is developed on the surface groups as a result of adsorption or desorption of ions that are constituents of the solid phase, i.e., H+, and the adsorption or desorption of solid-unlike ions that are not constituents of the solid phase. Highly weathered soils and subsoils (e.g., Oxisols and some Ultisols, Alfisols and Andisols) may undergo isoelectric weathering and reach a “zero net charge” stage during their development. They usually have a slightly acidic to acidic soil solution pH, which is close to either the point of zero net charge (PZNC) (3) or the point of zero salt effect (PZSE) (3). They are characterized by high abundances of minerals with a point of zero net proton charge (PZNPC) (3) at neutral and slightly basic pHs; the most important being Fe and Al oxides and allophane. Under acidic conditions, the surfaces of these minerals are net positively charged. In contrast, the surfaces of permanent charge phyllosilicates are negatively charged regardless of ambient conditions. Variable charge soils therefore, are heterogeneous charge systems.

  2. Variable Charge Soils: Mineralogy and Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Qafoku, Nik; Van Ranst, Eric; Noble, Andrew; Baert, Geert

    2003-11-01

    Soils rich in particles with amphoteric surface properties in the Oxisols, Ultisols, Alfisols, Spodosols and Andisols orders (1) are considered variable charge soils (2). The term “variable charge” is used to describe organic and inorganic soil constituents with reactive surface groups whose charge varies with pH, ionic concentration and composition of the soil solution. Such groups are the surface carboxyl, phenolic and amino functional groups of organic materials in soils, and surface hydroxyl groups of Fe and Al oxides, allophane and imogolite. The hydroxyl surface groups are also present on edges of some phyllosilicate minerals such as kaolinite, mica, and hydroxyl-interlayered vermiculite. The variable charge is developed on the surface groups as a result of adsorption or desorption of ions that are constituents of the solid phase, i.e., H+, and the adsorption or desorption of solid-unlike ions that are not constituents of the solid. Highly weathered soils usually undergo isoeletric weathering and reach a “zero net charge” stage during their development. They have a slightly acidic to acidic soil solution pH, which is close to either point of zero net charge (PZNC) (3) or point of zero salt effect (PZSE) (3). They are characterized by high abundances of minerals with a point of zero net proton charge (PZNPC) (3) at neutral and slightly basic pHs; the most important being Fe and Al oxides and allophane. Under acidic conditions, the surfaces of these minerals are net positively charged. In contrast, the surfaces of permanent charge phyllosilicates are negatively charged regardless of ambient conditions. Variable charge soils therefore, are heterogeneous charge systems. The coexistence and interactions of oppositely charged surfaces or particles confers a different pattern of physical and chemical behavior on the soil, relatively to a homogeneously charged system of temperate regions. In some variable charge soils (Oxisols and some Ultisols developed on

  3. Anion Exchange Capacity As a Mechanism for Deep Soil Carbon Storage in Variable Charge Soils

    Science.gov (United States)

    Dietzen, C.; James, J. N.; Ciol, M.; Harrison, R. B.

    2014-12-01

    Soil is the most important long-term sink for carbon (C) in terrestrial ecosystems, containing more C than plant biomass and the atmosphere combined. However, soil has historically been under-represented in C cycling literature, especially in regards to information about subsurface (>1.0 m) layers and processes. Previous research has indicated that Andisols with large quantities of noncrystalline, variable-charge minerals, including allophane, imogolite, and ferrihydrite, contain more C both in total and at depth than other soil types in the Pacific Northwest. The electrostatic charge of variable-charge soils depends on pH and is sometimes net positive, particularly in acid conditions, such as those commonly developed under the coniferous forests of the Pacific Northwest. However, even soils with a net negative charge may contain a mixture of negative and positive exchange sites and can hold some nutrient anions through the anion exchange capacity. To increase our understanding of the effects of variable-charge on soil organic matter stabilization, deep sampling is under way at the Fall River Long-Term Soil Productivity Site in western Washington. This site has a deep, well-drained soil with few rocks, which developed from weathered basalt and is classified as an Andisol of the Boistfort Series. Samples have been taken to a depth of 3 m at eight depth intervals. In addition to analyzing total soil C, these soils will be analyzed to determine functional groups present, cation exchange capacity, anion exchange capacity, and non-crystalline mineral content. These data will be analyzed to determine any correlations that may exist between these mineralogical characteristics, total soil C, and types of functional groups stored at depth. The most abundant organic functional groups, including carboxylic and phenolic groups, are anionic in nature, and soil positive charge may play an important role in binding and stabilizing soil organic matter and sequestering C.

  4. Chemical composition and Zn bioavailability of the soil solution extracted from Zn amended variable charge soils.

    Science.gov (United States)

    Zampella, Mariavittoria; Adamo, Paola

    2010-01-01

    A study on variable charge soils (volcanic Italian and podzolic Scottish soils) was performed to investigate the influence of soil properties on the chemical composition of soil solution. Zinc speciation, bioavailability and toxicity in the soil solution were examined. The soils were spiked with increasing amounts of Zn (0, 100, 200, 400 and 1000 mg/kg) and the soil solutions were extracted using rhizon soil moisture samplers. The pH, total organic carbon (TOC), base cations, anions, total Zn and free Zn2+ in soil solution were analysed. A rapid bioassay with the luminescent bacterium Escherichia coli HB101 pUCD607 was performed to assess Zn toxicity. The influence of soil type and Zn treatments on the chemical composition of soil solution and on Zn toxicity was considered and discussed. Different trends of total and free Zn concentrations, base cations desorption and luminescence of E. coli HB101 pUCD607 were observed. The soil solution extracted from the volcanic soils had very low total and free Zn concentrations and showed specific Zn2+/Ca2+ exchange. The soil solution from the podzolic soil had much higher total and free Zn concentrations and showed no evidence of specific Zn2+/Ca2+ exchange. In comparison with the subalkaline volcanic soils, the acidic podzol showed enhanced levels of toxic free Zn2+ and consequently stronger effects on E. coli viability.

  5. The Mineralogy, Chemistry, and Physics of Tropical Soils With Variable Charge Clays

    Science.gov (United States)

    Cassel, D. K.; Nielsen, D. R.

    This book is the culmination of an effort started in 1974 when the senior author started assembling information for a tropical soils course that he taught while on sabbatical leave at North Carolina State University. The literature cited throughout the book was current when the book went to press.Soil systems contain mineral and organic materials that have constant or permanent surface charges, such as montmorillonite, or constant surface potentials, usually referred to as variable charge materials. Most soil systems contain some of both kinds. In the tropics, most of the minerals with permanent charge have been severely weathered. Consequently, the surface charge of the remaining material results from adsorption of potential determining ions. This book treats the mineralogy, chemistry, and physics of the variable charge minerals and soil organic matter.

  6. Transport and Deposition of Variably Charged Soil Colloids in Saturated Porous Media

    DEFF Research Database (Denmark)

    Sharma, Anu; Kawmoto, Ken; Møldrup, Per

    2012-01-01

    A series of column experiments was conducted to investigate the transport and deposition of variably charged colloids in saturated porous media. Soil colloids with diameters volcanic-ash soil from Nishi-Tokyo (referred to here as VAS colloids) and a red-yellow soil from...... Okinawa (RYS colloids) in Japan. The VAS colloids exhibited a negative surface charge with a high pH dependency, whereas the RYS colloids exhibited a negative surface charge with less pH dependency. The soil colloids were applied as colloidal suspensions to 10-cm-long saturated sand columns packed....... Breakthrough curves and deposition profiles for soil colloids were strong functions of the hydrodynamics, solution pH, and surface charge of the colloids and sand grains. Greater deposition was typical for lower flow rates and lower pH. The deposition of VAS colloids in both sands under low-pH conditions...

  7. Adsorption properties of subtropical and tropical variable charge soils: Implications from climate change and biochar amendment

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ren-Kou; Qafoku, Nikolla; Van Ranst, Eric; Li, Jiu-yu; Jiang, Jun

    2016-01-25

    This review paper attempts to summarize the progress made in research efforts conducted over the last years to study the surface chemical properties of the tropical and subtropical soils, usually called variable charge soils, and the way they response to different management practices. The paper is composed of an introductory section that provides a brief discussion on the surface chemical properties of these soils, and five other review sections. The focus of these sections is on the evolution of surface chemical properties during the development of the variable charge properties (second section), interactions between oppositely charged particles and the resulting effects on the soil properties and especially on soil acidity (third section), the surface effects of low molecular weight organic acids sorbed to mineral surfaces and the chemical behavior of aluminum (fourth section), and the crop straw derived biochar induced changes of the surface chemical properties of these soils (fifth section). A discussion on the effect of climate change variables on the properties of the variable charge soils is included at the end of this review paper (sixth section).

  8. [Characteristics of DNA adsorption and desorption in variable and constant charge soil colloids].

    Science.gov (United States)

    Wang, Dai-Zhang; Wang, Shen-Yang; Jiang, Xin; Heng, Li-Sha; Tan, Jin-Fang; Liu, Shi-Liang; Cao, Yong-Xian

    2009-09-15

    The characteristics of adsorption and desorption of DNA by Red soil colloid, Latosol colloid, Chao colloid and Cinnamon colloid at different pH values were studied using a batch method. It showed that there was an increase of solution pH after adsorption of DNA by the four soil colloids in both NaCl and KCl electrolyte systems. The increasing ranges of pH values were in order of Red soil colloid > Latosol colloid > Chao colloid > Cinnamon colloid, and NaCl electrolyte system > KCl electrolyte system. The amounts of DNA adsorption on soil colloids decreased with the increase of pH value. The maximum amounts of DNA adsorption in different colloids were about 13.1-14.8 microg x mg(-1) when pH values were 2-4. The decreasing ranges of the amounts of DNA adsorption were about 5.5 microg x mg(-1) in NaCl electrolyte system and 2.1 Mg x mg(-1) in KCl electrolyte system in Red soil colloid and Latosol colloid after the rising of equilibrium solution pH from 4.2 to 8.6, whereas the remarked decreasing ranges of the adsorption amounts of DNA were about 8.3-12.2 microg x mg(-1) on Chao colloid and Cinnamon colloid in two electrolyte systems. The decreasing ranges of DNA adsorption were in order of the constant charge (Chao soil and Cinnamon) colloids > the variable charge (Red soil and Latosol) colloids. The differences of desorption on the variable and the constant charge colloids are very significant while the DNA adsorbed was desorbed with NaOAc solution and NaH2 PO4 solution. The desorption percent desorption of DNA as NaH2PO4 desorbent was 23.5%-40.2% larger on the variable charge colloids than 8.8%-21.6% on the constant charge of colloids at the three different solution pH values of 3, 5 and 7, while that as NaOAc desorbent was 72.3%-85.9% larger on the constant charge colloids than 10%-24.5% on the variable charge colloids. These results implied that the ligand exchange played a more important role in DNA adsorption on the variable charge colloids, and electrostatic

  9. The Role of Variable-Charge Minerals in Deep Soil Carbon Storage in a Pacific Northwest Andisol

    Science.gov (United States)

    Dietzen, C.; Root, A.; James, J. N.; Holub, S. M.; Harrison, R. B.

    2015-12-01

    Soil is the most important long-term sink for carbon (C) in terrestrial ecosystems, containing more C than plant biomass and the atmosphere combined. However, soil has historically been under-represented in C cycling literature, especially in regards to information about subsurface (>1.0 m) layers and processes. Previous research has indicated that Andisols with large quantities of noncrystalline, variable-charge minerals, including allophane, imogolite, and ferrihydrite, contain more C both in total and at depth than other soil types in the Pacific Northwest. The electrostatic charge of variable-charge soils depends on pH and is sometimes net positive, particularly in acid conditions, such as those commonly developed under the coniferous forests of the Pacific Northwest. However, even soils with a net negative charge may contain a mixture of negative and positive exchange sites and can hold some nutrient anions through the anion exchange capacity. The most abundant organic functional groups, including carboxylic and phenolic groups, are anionic in nature, and soil positive charge may play an important role in binding and stabilizing soil organic matter and sequestering C. To increase our understanding of the role of variable-charge minerals in soil organic matter stabilization in deep soils, samples were taken to a depth of 3 m at the Fall River Long-Term Soil Productivity Site in western Washington. This site has a deep, well-drained soil with few rocks, which developed from weathered basalt and is classified as an Andisol of the Boistfort Series. Analysis of soil charge characteristics over a pH range allowed for the determination of anion exchange capacity and point of zero net charge at 8 depth intervals. These results, along with total carbon analysis and C-14 dating at each depth interval, are used to evaluate the importance of the anion exchange capacity as a mechanism for storing carbon at depth in variable-charge soils.

  10. Adsorption of glyphosate on variable-charge, volcanic ash-derived soils.

    Science.gov (United States)

    Cáceres-Jensen, L; Gan, J; Báez, M; Fuentes, R; Escudey, M

    2009-01-01

    Glyphosate (N-phosphonometylglycine) is widely used due to its broad spectrum of activity and nonselective mode of action. In Chile it is the most used herbicide, but its adsorption behavior in the abundant and widespread variable charge soils is not well understood. In this study, three volcanic ash-derived soils were selected, including Andisols (Nueva Braunau and Diguillin) and Ultisols (Collipulli), to evaluate the adsorption kinetics, equilibrium isotherms, and the effect of pH in glyphosate adsorption. The influence of glyphosate on soil phosphorus retention was also studied. Glyphosate was rapidly and strongly adsorbed on the selected soils, and adsorption isotherms were well described by the Freundlich relationship with strong nonlinearity (n(fads) soils without the addition of glyphosate had similar mean K(ads) values for Nueva Braunau (5.68) and Diguillin (7.38). Collipulli had a mean K(ads) value of 31.58. During the successive desorption steps, glyphosate at the highest level increased K(ads) values for phosphate in the Andisol soils but had little effect in the Ultisol soil. This different behavior was probably due to the irreversible occupation of some adsorption sites by glyphosate in the Ultisol soil attributed to the dominant Kaolinite mineral. Results from this study suggest that in the two types of volcanic soils, different mechanisms are involved in glyphosate and phosphate adsorption and that long-term use of glyphosate may impose different effects on the retention and availability of phosphorus. Volcanic ash-derived soils have a particular environmental behavior in relation to the retention of organic contaminants, representing an environmental substrate that may become highly polluted over time due to intensive agronomic uses.

  11. Surface Complexation Modeling in Variable Charge Soils: Charge Characterization by Potentiometric Titration

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    Giuliano Marchi

    2015-10-01

    Full Text Available ABSTRACT Intrinsic equilibrium constants of 17 representative Brazilian Oxisols were estimated from potentiometric titration measuring the adsorption of H+ and OH− on amphoteric surfaces in suspensions of varying ionic strength. Equilibrium constants were fitted to two surface complexation models: diffuse layer and constant capacitance. The former was fitted by calculating total site concentration from curve fitting estimates and pH-extrapolation of the intrinsic equilibrium constants to the PZNPC (hand calculation, considering one and two reactive sites, and by the FITEQL software. The latter was fitted only by FITEQL, with one reactive site. Soil chemical and physical properties were correlated to the intrinsic equilibrium constants. Both surface complexation models satisfactorily fit our experimental data, but for results at low ionic strength, optimization did not converge in FITEQL. Data were incorporated in Visual MINTEQ and they provide a modeling system that can predict protonation-dissociation reactions in the soil surface under changing environmental conditions.

  12. Removal of pollutants by enhanced coagulation combined PAC with variable charge soils: flocs' properties and effect of pH.

    Science.gov (United States)

    Wang, Yu-Jie; Wu, Chun-De; Duan, Yan; Zhang, Zhi-Lin

    2016-09-01

    This study investigated the properties of flocs and effects of the solution pH on removal of representative pollutants by enhanced coagulation with variable charge soils of South China and polyaluminum chloride (PAC). The results demonstrated that the removal efficiency of turbidity was larger and the aggregated flocs had a faster growth rate, bigger size, denser structure and faster settling rate than those generated by PAC alone, when variable charge soil was used in conjunction with PAC. Additionally, initial solutions pH had meaningful effects on removal of pollutants. With the increase in the pH of the solution, the removal efficiencies of turbidity, algae and heavy metal ions significantly increased. Besides, charge neutralization together with physical entrapment of colloids was the dominant mechanism in enhanced coagulation, and variable charge soil displayed a great adsorption effect.

  13. Sorption-bioavailability nexus of arsenic and cadmium in variable-charge soils.

    Science.gov (United States)

    Bolan, Nanthi; Mahimairaja, Santiago; Kunhikrishnan, Anitha; Naidu, Ravi

    2013-10-15

    In this work, the nexus between sorption and bioavailability of arsenic (As) and cadmium (Cd) as affected by soil type, soil pH, ageing, and mobilizing agents were examined. The adsorption of As and Cd was examined using a number of allophanic and non-allophanic soils which vary in their charge components. The effect of pH and ageing on the bioavailability of As and Cd was examined using spiked soils in a plant growth experiment. The effect of phosphate (P)-induced mobility of As on its bioavailability was examined using a naturally contaminated sheep dip soil. The results indicated that the adsorption of both As and Cd varied amongst the soils, and the difference in Cd adsorption is attributed to the difference in surface charge. An increase in soil pH increased net negative charge by an average of 45.7 mmol/kg/pH thereby increasing cation (Cd) adsorption; whereas, the effect of pH on anion (As) adsorption was inconsistent. The bioavailability of As and Cd decreased by 3.31- and 2.30-fold, respectively, with ageing which may be attributed to increased immobilization. Phosphate addition increased the mobility and bioavailability of As by 4.34- and 3.35-fold, respectively, in the sheep dip soil. However, the net effect of P on As phytoavailability depends on the extent of P-induced As mobilization in soils and P-induced competition for As uptake by roots. The results demonstrate the nexus between sorption and bioavailability of As and Cd in soils, indicating that the effects of various factors on bioavailability are mediated through their effects on sorption reactions. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Effect of low-molecular-weight organic acids on the adsorption of norfloxacin in typical variable charge soils of China.

    Science.gov (United States)

    Zhang, Jin-qiang; Dong, Yuan-hua

    2008-03-01

    Batch equilibrium experiments were used to study the adsorption of norfloxacin (NOR) onto three kinds of variable charge soils in China, namely Rho-Udic Ferralisols collected from Yunnan, Ali-Perudic Ferrisols collected from Jiangxi and Typ-Hap-Udic Ferralisols collected from Guangdong. Results show that NOR is strongly adsorbed by the soils, with lg Kd-values (linear model) of 4.41+/-0.01, 4.50+/-0.02, 4.44+/-0.01 and lg Kf-values (Freundlich model) of 4.32, 4.45, 3.08 for the three tested soils, respectively. Both curves of the Freundlich equation and Langmuir equation for the three soils were in excellent linear correlation. Low-molecular-weight (LMW) organic acids, including citric acid, malic acid and salicylic acid were added in the presence of acetate buffer (pH 4.5) to test their effects on NOR adsorption. It was observed that the addition of LMW organic acids inhibited the NOR adsorption process. It was assumed that several effects, including soil pH, solid surface charge and competitive adsorption of co-existing cations, dominated the NOR sorption processes onto variable charge soils. Further studies should be performed to reveal the mechanism of the adsorption.

  15. Surface Complexation Modeling in Variable Charge Soils: Prediction of Cadmium Adsorption

    Directory of Open Access Journals (Sweden)

    Giuliano Marchi

    2015-10-01

    Full Text Available ABSTRACT Intrinsic equilibrium constants for 22 representative Brazilian Oxisols were estimated from a cadmium adsorption experiment. Equilibrium constants were fitted to two surface complexation models: diffuse layer and constant capacitance. Intrinsic equilibrium constants were optimized by FITEQL and by hand calculation using Visual MINTEQ in sweep mode, and Excel spreadsheets. Data from both models were incorporated into Visual MINTEQ. Constants estimated by FITEQL and incorporated in Visual MINTEQ software failed to predict observed data accurately. However, FITEQL raw output data rendered good results when predicted values were directly compared with observed values, instead of incorporating the estimated constants into Visual MINTEQ. Intrinsic equilibrium constants optimized by hand calculation and incorporated in Visual MINTEQ reliably predicted Cd adsorption reactions on soil surfaces under changing environmental conditions.

  16. Cargas elétricas estruturais e variáveis de solos tropicais altamente intemperizados Structural and variable electric charges of highly weathered tropical soils

    Directory of Open Access Journals (Sweden)

    Oscarlina Lucia dos Santos Weber

    2005-12-01

    Full Text Available Os solos tropicais altamente intemperizados apresentam teor significativo de colóides com carga elétrica variável. Entretanto, são poucas as referências em relação à quantificação destas cargas, principalmente em solos ácricos, que representam o extremo na escala de intemperismo. Neste estudo, foram determinadas as cargas permanentes e as variáveis de dois Latossolos Vermelhos acriférricos, um Latossolo Amarelo ácrico e um Latossolo Amarelo acriférrico, que foram comparados a um Nitossolo Vermelho eutroférrico, com carga predominantemente permanente. As amostras foram investigadas pelo método da adsorção do íon césio (Cs+, que mede a carga estrutural permanente (sigmao e baseia-se na preferência do Cs+ sobre o Li+ na superfície da siloxana de grupos de superfície ionizáveis de menor seletividade ao íon Cs+. A carga variável representou mais que 50 % da carga total dos solos estudados. Dois dos quatro Latossolos com propriedades ácricas exibiram quantidade significativa de carga permanente, provavelmente em razão da presença de vermiculita com hidróxi entrecamadas e clorita. A quantidade de carga permanente apresentada pelo Nitossolo foi até cinco vezes maior se comparada à dos Latossolos, o que pode ser atribuído à diferença na constituição mineralógica. O método da adsorção de Cs foi capaz de identificar teores significativos de carga permanente estrutural, mesmo em solos com baixo teor de minerais 2:1.Highly weathered tropical soils present high amount of colloids with variable electrical charge. However, there are few references related to the quantification of such charges, mainly in soils with acric attributes, which represent one of the extremes in the weathering scale. In this study permanent and variable charges were determined in four Oxisols and compared to an Alfisol with predominantly permanent charge. Samples were investigated using the Cs+ adsorption method, which measures the structural

  17. Review of Variable Generation Integration Charges

    Energy Technology Data Exchange (ETDEWEB)

    Porter, K.; Fink, S.; Buckley, M.; Rogers, J.; Hodge, B. M.

    2013-03-01

    The growth of wind and solar generation in the United States, and the expectation of continued growth of these technologies, dictates that the future power system will be operated in a somewhat different manner because of increased variability and uncertainty. A small number of balancing authorities have attempted to determine an 'integration cost' to account for these changes to their current operating practices. Some balancing authorities directly charge wind and solar generators for integration charges, whereas others add integration charges to projected costs of wind and solar in integrated resource plans or in competitive solicitations for generation. This report reviews the balancing authorities that have calculated variable generation integration charges and broadly compares and contrasts the methodologies they used to determine their specific integration charges. The report also profiles each balancing authority and how they derived wind and solar integration charges.

  18. Soil variability in engineering applications

    Science.gov (United States)

    Vessia, Giovanna

    2014-05-01

    Natural geomaterials, as soils and rocks, show spatial variability and heterogeneity of physical and mechanical properties. They can be measured by in field and laboratory testing. The heterogeneity concerns different values of litho-technical parameters pertaining similar lithological units placed close to each other. On the contrary, the variability is inherent to the formation and evolution processes experienced by each geological units (homogeneous geomaterials on average) and captured as a spatial structure of fluctuation of physical property values about their mean trend, e.g. the unit weight, the hydraulic permeability, the friction angle, the cohesion, among others. The preceding spatial variations shall be managed by engineering models to accomplish reliable designing of structures and infrastructures. Materon (1962) introduced the Geostatistics as the most comprehensive tool to manage spatial correlation of parameter measures used in a wide range of earth science applications. In the field of the engineering geology, Vanmarcke (1977) developed the first pioneering attempts to describe and manage the inherent variability in geomaterials although Terzaghi (1943) already highlighted that spatial fluctuations of physical and mechanical parameters used in geotechnical designing cannot be neglected. A few years later, Mandelbrot (1983) and Turcotte (1986) interpreted the internal arrangement of geomaterial according to Fractal Theory. In the same years, Vanmarcke (1983) proposed the Random Field Theory providing mathematical tools to deal with inherent variability of each geological units or stratigraphic succession that can be resembled as one material. In this approach, measurement fluctuations of physical parameters are interpreted through the spatial variability structure consisting in the correlation function and the scale of fluctuation. Fenton and Griffiths (1992) combined random field simulation with the finite element method to produce the Random

  19. [Characteristics of zero point of charge of volcanic ash soils in Changbaishan and Wudalianchi].

    Science.gov (United States)

    Zhao, Lanpo; Yang, Xueming; Liu, Wei

    2003-10-01

    The characteristics of the zero point of charge (ZPC) of volcanic ash soil profiles in Changbaishan and Wudalianchi was studied and discussed by means of potentiometric titration curves. The results showed that the two volcanic ash soils had not only a little variable charg, but also a little permanent charge. The clay fractions of the volcanic ash soils carried both variable and permanent charges. The ZPC of eeach layer in both soil profiles all lied in the acid side of titration curve, and increased with increasing soil depth. However, the ZPC displacements (sigma i) decreased with increasing soil depth. The ZPC of surface layer in both soil profiles was lower than that of the volcanic ash soils in foreign countries, but obviously higher than that of Loess soil in the Northwest and of black soil in the Northeast China. The variation of ZPC and delta i was affected not only by the deposition of long-rang tropospheric eolian dust from the Asian continent, but also by the accumulation of soil organic matter. Their combined effect was the main reason to the decrease of ZPC and sigma i the increase of sigma i in Changbaishan and Wudalianchi volcanic ash soils.

  20. Copper desorption in a soil with variable charge Dessorção de cobre em solo com carga variável

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    José Carlos Casagrande

    2004-04-01

    Full Text Available Adsorption processes of heavy metals in soils have been more extensively studied than desorption, in spite of this latter process being related to nutrient bioavailability in the soil solution. Copper desorption from surface (0-0.2 m and subsurface (1.0 - 1.2 m samples of an Anionic Acrudox was studied at two pH values (4.5 and 7.5. Soil samples were incubated with Cu rates varying from 0 to 400 mg kg-1, during 4 and 12 weeks, in the presence of CaCl2 as support electrolyte at concentrations of 0.01 and 0.001 mol L-1. Complete soil adsorption of added Cu was observed at pH 7.5 in all incubation periods, indicating that a 24h-shaking period was enough to reach equilibrium and maximum adsorption. Copper adsorption varied with the incubation period and was much lower at pH 4.5 than at pH 7.5, after the 24 hour-incubation period. After 4 and 12 weeks, Cu adsorption values were higher and similar for all soil samples, irrespective of pH or depth of sampling. The effect of the incubation period on soil Cu adsorption surpassed the pH effect for all Cu rates. The hysteresis was expressive, suggesting that Cu enhances high-energy bonds with the soil colloids. Calcium chloride was not efficient in promoting native soil Cu desorption in the studied concentrations.A adsorção de metais pesados aos solos é mais estudada do que sua dessorção. No entanto, o processo de dessorção está diretamente relacionado à disponibilidade dos elementos às plantas. A dessorção de cobre em amostras superficiais (0-0,2 m e subsuperficiais (1,0-1,2 m de um Latossolo Vermelho acriférrico foi estudada em dois valores de pH (4,5 e 7,5. Foram adicionados até 400 mg kg-1 de Cu em amostras incubadas por 4 e 12 semanas, tendo o CaCl2 como eletrólito suporte nas concentrações de 0,01 e 0,001 mol L-1. No pH mais elevado (7,5, em todos os períodos de incubação, as amostras adsorveram praticamente todo o cobre adicionado, indicando que o tempo de 24 h de agitação para

  1. Predictor variable resolution governs modeled soil types

    Science.gov (United States)

    Soil mapping identifies different soil types by compressing a unique suite of spatial patterns and processes across multiple spatial scales. It can be quite difficult to quantify spatial patterns of soil properties with remotely sensed predictor variables. More specifically, matching the right scale...

  2. Collision and recombination driven instabilities in variable charged ...

    Indian Academy of Sciences (India)

    2Department of AEIE, Dream Institute of Technology, Kolkata, India. ∗. Corresponding author. E-mail: mridulbose@yahoo.co.in. MS received 15 February 2012; accepted 12 October 2012. Abstract. The dust-acoustic instability driven by recombination of electrons and ions on the sur- face of charged and variably-charged ...

  3. Variable Charge of Ultisols due to Phosphate Application and Incubation Time

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    Muhammad Mahbub

    2010-05-01

    Full Text Available The laboratoryexperiment was conducted to study the effect of phosphate (P application and its incubation time on pHo (pH at thepoint of zero charge and variable charge of ultisols . The determined parameters were pHo and variable surfacecharges.Soil samples were added by 0, 375 and 1,125 mg P kg-1 (or 0, 50 and 150% of the P sorption maximum,respectively. Then, they were incubated for 2, 4, 6 and 8 weeks. The variable surface-charges and pHo weredetermined by using the activity of potential determining ions (H+ and OH- within two salt concentrations as counterions (0.1N and 0.001N CaCl2 through a potentiometric titration method. The results were indicated that the high Psorption and 766 mg P kg-1 in maximum sorption were due to high contents in clay fractions and aluminum as well aslow pH of experimental soil. Application of P and incubation time were able to decrease pHo and to increase negativesurface-charges. Additionals of 375 and 1.125 mg P kg-1 incubated for 8 weeks gave the value of pHo 2.86 and 2.69;as well as the magnitude of negative charges 14.48 and 16.76 cmol(-.kg-1, respectively (both for 0.001N CaCl2.For pH > pHo (the characteristic of variable charge soils, the higher the salt (CaCl2 concentration and pH solution,the higher the negative surface-charge.

  4. Seasonal variability of soil aggregate stability

    Science.gov (United States)

    Rohoskova, M.; Kodesova, R.; Jirku, V.; Zigova, A.; Kozak, J.

    2009-04-01

    Seasonal variability of soil properties measured in surface horizons of three soil types (Haplic Luvisol, Greyic Phaeozem, Haplic Cambisol) was studied in years 2007 and 2008. Undisturbed and disturbed soil samples were taken every month to evaluate field water content, bulk density, porosity, ration of gravitational and capillary pores, pHKCl and pHH2O, organic matter content and its quality, aggregate stability using WSA index. In addition, micromorphological features of soil aggregates were studied in thin soil sections that were made from undisturbed large soil aggregates. Results showed that soil aggregate stability depended on stage of the root zone development, soil management and climatic conditions. Larger aggregate stabilities and also larger ranges of measure values were obtained in the year 2007 then those measured in 2008. This was probably caused by lower precipitations and consequently lower soil water contents observed in 2007 than those measured in 2008. The highest aggregate stability was measured at the end of April in the years 2007 and 2008 in Haplic Luvisol and Greyic Phaeozem, and at the end of June in the year 2007 and at the beginning of June in 2008 in Haplic Cambisol. In all cases aggregate stability increased during the root growth and then gradually decreased due to summer rainfall events. Aggregate stability reflected aggregate structure and soil pore system development, which was documented on micromorphological images and evaluated using the ration of gravitational and capillary pores measured on the undisturbed sol samples. Acknowledgement: Authors acknowledge the financial support of the Grant Agency of the Czech Republic grant No. 526/08/0434, and the Ministry of Education, Youth and Sports grant No. MSM 6046070901.

  5. Dry-end surface soil moisture variability during NAFE'06

    NARCIS (Netherlands)

    Teuling, A.J.; Uijlenhoet, R.; Hurkmans, R.T.W.L.; Merlin, O.; Panciera, R.; Walker, J.P.; Troch, P.A.

    2007-01-01

    Characterization of the space-time variability of soil moisture is important for land surface and climate studies. Here we develop an analytical model to investigate how, at the dry-end of the soil moisture range, the main characteristics of the soil moisture field (spatial mean and variability,

  6. Temporal variability in soil hydraulic properties under drip irrigation

    OpenAIRE

    Mubarak, I.; Mailhol, J.C.; Angulo-Jaramillo, R.; Ruelle, P.; P. Boivin; M. R. Khaledian

    2009-01-01

    Predicting soil hydraulic properties and understanding their temporal variability during the irrigated cropping season are required to mitigate agro-environmental risks. This paper reports field measurements of soil hydraulic properties under two drip irrigation treatments, full (FT) and limited (LT). The objective was to identify the temporal variability of the hydraulic properties of field soil under high-frequency water application during a maize cropping season. Soil hydraulics were chara...

  7. Impact of soil variability on irrigated and rainfed cotton

    Science.gov (United States)

    Cotton is a vital component of the economies of Mid-South states. Producers and landowners are looking for ways to reduce the variability of irrigated yields and soil apparent electrical conductivity (ECa) is a readily obtained parameter that can indicate soil variability. A study was conducted in 2...

  8. Phosphorus solubility of agricultural soils: a surface charge and phosphorus-31 NMR speciation study

    Science.gov (United States)

    We investigated ten soils from six states in United States to determine the relationship between potentiometric titration derived soil surface charge and Phosphorus-31 (P) nuclear magnetic resonance (NMR) speciation with the concentration of water-extractable P (WEP). The surface charge value at the...

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

    Science.gov (United States)

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

  10. Spatial Variability of Soil Properties and its Impact on Simulated Surface Soil Moisture Patterns

    Science.gov (United States)

    Korres, W.; Bothe, T.; Reichenau, T. G.; Schneider, K.

    2015-12-01

    The spatial variability of soil properties (particle size distribution, PSD, and bulk density, BD) has large effects on the spatial variability of soil moisture and therefore on plant growth and surface exchange processes. In model studies, soil properties from soil maps are considered homogeneous over mapping units, which neglects the small scale variability of soil properties and leads to underestimated small scale variability of simulated soil moisture. This study focuses on the validation of spatial variability of simulated surface soil moisture (SSM) in a winter wheat field in Western Germany using the eco-hydrological simulation system DANUBIA. SSM measurements were conducted at 20 different sampling points and nine different dates in 2008. Frequency distributions of BD and PSD were derived from an independent dataset (n = 486) of soil physical properties from Germany and the USA. In the simulations, BD and PSD were parameterized according to these frequency distributions. Mean values, coefficients of variation and frequency distributions of simulated SSM were compared to the field measurements. Using the heterogeneous model parameterization, up to 76 % of the frequency distribution of the measured SSM can be explained. Furthermore, the results show that BD has a larger impact on the variability of SSM than PSD. The introduced approach can be used for simulating mean SSM and SSM variability more accurately and can form the basis for a spatially heterogeneous parameterization of soil properties in mesoscale models.

  11. Topographic variability influences the carbon sequestration potential of arable soils

    DEFF Research Database (Denmark)

    Chirinda, Ngoni; Elsgaard, Lars; Thomsen, Ingrid Kaag

    2012-01-01

    There is presently limited knowledge on the influence of field spatial variability on the carbon (C) sink-source relationships in arable landscapes. This is accompanied by the fact that our understanding of soil profile C dynamics is also limited. This study aimed at investigating how spatial...... variability along a short catena influences C sinksource relationships and temporal dynamics of CO2 concentrations in soils. In spring 2011, soil samples were collected from topsoil (2-5.5 cm) and subsoil (38-41.5 cm) horizons at upslope and footslope positions in a Danish winter wheat field on a sandy loam...... soil developed on glacial till. Bulk densities and C concentrations of the soils were characterized. From June 2011, gas samples were collected at least bimonthly from the same slope positions in four spatial replicates using stainless steel needles that were permanently installed at 5, 10, 20 and 30...

  12. Characterization of soil water content variability and soil texture using GPR groundwave techniques

    Energy Technology Data Exchange (ETDEWEB)

    Grote, K.; Anger, C.; Kelly, B.; Hubbard, S.; Rubin, Y.

    2010-08-15

    Accurate characterization of near-surface soil water content is vital for guiding agricultural management decisions and for reducing the potential negative environmental impacts of agriculture. Characterizing the near-surface soil water content can be difficult, as this parameter is often both spatially and temporally variable, and obtaining sufficient measurements to describe the heterogeneity can be prohibitively expensive. Understanding the spatial correlation of near-surface soil water content can help optimize data acquisition and improve understanding of the processes controlling soil water content at the field scale. In this study, ground penetrating radar (GPR) methods were used to characterize the spatial correlation of water content in a three acre field as a function of sampling depth, season, vegetation, and soil texture. GPR data were acquired with 450 MHz and 900 MHz antennas, and measurements of the GPR groundwave were used to estimate soil water content at four different times. Additional water content estimates were obtained using time domain reflectometry measurements, and soil texture measurements were also acquired. Variograms were calculated for each set of measurements, and comparison of these variograms showed that the horizontal spatial correlation was greater for deeper water content measurements than for shallower measurements. Precipitation and irrigation were both shown to increase the spatial variability of water content, while shallowly-rooted vegetation decreased the variability. Comparison of the variograms of water content and soil texture showed that soil texture generally had greater small-scale spatial correlation than water content, and that the variability of water content in deeper soil layers was more closely correlated to soil texture than were shallower water content measurements. Lastly, cross-variograms of soil texture and water content were calculated, and co-kriging of water content estimates and soil texture

  13. Observation of soil moisture variability in agricultural and grassland field soils using a wireless sensor network

    Science.gov (United States)

    Priesack, Eckart; Schuh, Max

    2014-05-01

    Soil moisture dynamics is a key factor of energy and matter exchange between land surface and atmosphere. Therefore long-term observation of temporal and spatial soil moisture variability is important in studying impacts of climate change on terrestrial ecosystems and their possible feedbacks to the atmosphere. Within the framework of the network of terrestrial environmental observatories TERENO we installed at the research farm Scheyern in soils of two fields (of ca. 5 ha size each) the SoilNet wireless sensor network (Biogena et al. 2010). The SoilNet in Scheyern consists of 94 sensor units, 45 for the agricultural field site and 49 for the grassland site. Each sensor unit comprises 6 SPADE sensors, two sensors placed at the depths 10, 30 and 50 cm. The SPADE sensor (sceme.de GmbH, Horn-Bad Meinberg Germany) consists of a TDT sensor to estimate volumetric soil water content from soil electrical permittivity by sending an electromagnetic signal and measuring its propagation time, which depends on the soil dielectric properties and hence on soil water content. Additionally the SPADE sensor contains a temperature sensor (DS18B20). First results obtained from the SoilNet measurements at both fields sites will be presented and discussed. The observed high temporal and spatial variability will be analysed and related to agricultural management and basic soil properties (bulk density, soil texture, organic matter content and soil hydraulic characteristics).

  14. Method and apparatus for smart battery charging including a plurality of controllers each monitoring input variables

    Science.gov (United States)

    Hammerstrom, Donald J.

    2013-10-15

    A method for managing the charging and discharging of batteries wherein at least one battery is connected to a battery charger, the battery charger is connected to a power supply. A plurality of controllers in communication with one and another are provided, each of the controllers monitoring a subset of input variables. A set of charging constraints may then generated for each controller as a function of the subset of input variables. A set of objectives for each controller may also be generated. A preferred charge rate for each controller is generated as a function of either the set of objectives, the charging constraints, or both, using an algorithm that accounts for each of the preferred charge rates for each of the controllers and/or that does not violate any of the charging constraints. A current flow between the battery and the battery charger is then provided at the actual charge rate.

  15. Genetic variability in soybean ( Glycine max L.) for low soil ...

    African Journals Online (AJOL)

    Assessment of the genetic variability of soybean genotypes under low soil phosphorus (P) conditions provides an understanding of the genetic potential of the genotypes to improve the crop for low P tolerance. The study was designed objectively to estimate the extent of genetic variability of soybean genotypes for low P ...

  16. Variability of Measured Runoff and Soil Loss from Field Plots

    Directory of Open Access Journals (Sweden)

    F. Asadzadeh

    2016-02-01

    Full Text Available Introduction: Field plots are widely used in studies related to the measurements of soil loss and modeling of erosion processes. Research efforts are needed to investigate factors affecting the data quality of plots. Spatial scale or size of plots is one of these factors which directly affects measuring runoff and soil loss by means of field plots. The effect of plot size on measured runoff or soil loss from natural plots is known as plot scale effect. On the other hand, variability of runoff and sediment yield from replicated filed plots is a main source of uncertainty in measurement of erosion from plots which should be considered in plot data interpretation processes. Therefore, there is a demand for knowledge of soil erosion processes occurring in plots of different sizes and of factors that determine natural variability, as a basis for obtaining soil loss data of good quality. This study was carried out to investigate the combined effects of these two factors by measurement of runoff and soil loss from replicated plots with different sizes. Materials and Methods: In order to evaluate the variability of runoff and soil loss data seven plots, differing in width and length, were constructed in a uniform slope of 9% at three replicates at Koohin Research Station in Qazvin province. The plots were ploughed up to down slope in September 2011. Each plot was isolated using soil beds with a height of 30 cm, to direct generated surface runoff to the lower part of the plots. Runoff collecting systems composed of gutters, pipes and tankswere installed at the end of each plot. During the two-year study period of 2011-2012, plots were maintained in bare conditions and runoff and soil loss were measured for each single event. Precipitation amounts and characteristics were directly measured by an automatic recording tipping-bucket rain gauge located about 200 m from the experimental plots. The entire runoff volume including eroded sediment was measured on

  17. Electrical resistivity tomography to delineate greenhouse soil variability

    Science.gov (United States)

    Rossi, R.; Amato, M.; Bitella, G.; Bochicchio, R.

    2013-03-01

    Appropriate management of soil spatial variability is an important tool for optimizing farming inputs, with the result of yield increase and reduction of the environmental impact in field crops. Under greenhouses, several factors such as non-uniform irrigation and localized soil compaction can severely affect yield and quality. Additionally, if soil spatial variability is not taken into account, yield deficiencies are often compensated by extra-volumes of crop inputs; as a result, over-irrigation and overfertilization in some parts of the field may occur. Technology for spatially sound management of greenhouse crops is therefore needed to increase yield and quality and to address sustainability. In this experiment, 2D-electrical resistivity tomography was used as an exploratory tool to characterize greenhouse soil variability and its relations to wild rocket yield. Soil resistivity well matched biomass variation (R2=0.70), and was linked to differences in soil bulk density (R2=0.90), and clay content (R2=0.77). Electrical resistivity tomography shows a great potential in horticulture where there is a growing demand of sustainability coupled with the necessity of stabilizing yield and product quality.

  18. Effect of Particle Size and Soil Compaction on Gas Transport Parameters in Variably Saturated, Sandy Soils

    DEFF Research Database (Denmark)

    Hamamoto, Shoichiro; Møldrup, Per; Kawamoto, Ken

    2009-01-01

    the water retention curve), both exhibiting similar and exponential relationships with D50. Under variably saturated conditions, higher Dp and ka in coarser sand (larger D50) were observed due to rapid gas diffusion and advection through the less tortuous large-pore networks. In addition, soil compaction......The soil gas diffusion coefficient (Dp) and air permeability (ka) and their dependency on soil air content ( ) control gas diffusion and advection in soils. This study investigated the effects of average particle size (D50) and dry bulk density ( b) on Dp and ka for six sandy soils under variably...... saturated conditions. Data showed that particle size markedly affects the effective diameter of the drained pores active in leading gas through the sample at –100 cm H2O of soil water matric potential (calculated from Dp and ka) as well as the average pore diameter at half saturation (calculated from...

  19. Electric Vehicle Routing Problem with Charging Time and Variable Travel Time

    OpenAIRE

    Sai Shao; Wei Guan; Bin Ran; Zhengbing He; Jun Bi

    2017-01-01

    An electric vehicle routing problem with charging time and variable travel time is developed to address some operational issues such as range limitation and charging demand. The model is solved by using genetic algorithm to obtain the routes, the vehicle departure time at the depot, and the charging plan. Meanwhile, a dynamic Dijkstra algorithm is applied to find the shortest path between any two adjacent nodes along the routes. To prevent the depletion of all battery power and ensure safe op...

  20. Sensitivity of soil respiration to variability in soil moisture and temperature in a humid tropical forest

    Science.gov (United States)

    Tana Wood; M. Detto; W.L. Silver

    2013-01-01

    Precipitation and temperature are important drivers of soil respiration. The role of moisture and temperature are generally explored at seasonal or inter-annual timescales; however, significant variability also occurs on hourly to daily time-scales. We used small (1.54 m2), throughfall exclusion shelters to evaluate the role soil moisture and temperature as temporal...

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

    Science.gov (United States)

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

    2004-01-01

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

  2. On the role of "internal variability" on soil erosion assessment

    Science.gov (United States)

    Kim, Jongho; Ivanov, Valeriy; Fatichi, Simone

    2017-04-01

    Empirical data demonstrate that soil loss is highly non-unique with respect to meteorological or even runoff forcing and its frequency distributions exhibit heavy tails. However, all current erosion assessments do not describe the large associated uncertainties of temporal erosion variability and make unjustified assumptions by relying on central tendencies. Thus, the predictive skill of prognostic models and reliability of national-scale assessments have been repeatedly questioned. In this study, we attempt to reveal that the high variability in soil losses can be attributed to two sources: (1) 'external variability' referring to the uncertainties originating at macro-scale, such as climate, topography, and land use, which has been extensively studied; (2) 'geomorphic internal variability' referring to the micro-scale variations of pedologic properties (e.g., surface erodibility in soils with multi-sized particles), hydrologic properties (e.g., soil structure and degree of saturation), and hydraulic properties (e.g., surface roughness and surface topography). Using data and a physical hydraulic, hydrologic, and erosion and sediment transport model, we show that the geomorphic internal variability summarized by spatio-temporal variability in surface erodibility properties is a considerable source of uncertainty in erosion estimates and represents an overlooked but vital element of geomorphic response. The conclusion is that predictive frameworks of soil erosion should embed stochastic components together with deterministic assessments, if they do not want to largely underestimate uncertainty. Acknowledgement: This study was supported by the Basic Science Research Program of the National Research Foundation of Korea funded by the Ministry of Education (2016R1D1A1B03931886).

  3. Comparing the Ability of Conventional and Digital Soil Maps to Explain Soil Variability using Diversity Indices

    Directory of Open Access Journals (Sweden)

    zohreh mosleh

    2017-06-01

    Full Text Available Introduction: Effective and sustainable soil management requires knowledge about the spatial patterns of soil variation and soil surveys are important and useful sources of data that can be used. Prior knowledge about the spatial distribution of the soils is the first essential step for this aim but this requires the collection of large amounts of soil information. However, the conventional soil surveys are usually not useful for providing quantitative information about the spatial distribution of soil properties that are used in many environmental studies. Recently, by the rapid development of the computers and technology together with the availability of new types of remote sensing data and digital elevation models (DEMs, digital and quantitative approaches have been developed. These new techniques relies on finding the relationships between soil properties or classes and the auxiliary information that explain the soil forming factors or processes and finally predict soil patterns on the landscape. Different types of the machine learning approaches have been applied for digital soil mapping of soil classes, such as the logistic and multinomial logistic regressions, neural networks and classification trees. In reality, soils are physical outcomes of the interactions happening among the geology, climate, hydrology and geomorphic processes. Diversity is a way of measuring soil variation. Ibanez (9 first introduced ecological diversity indices as measures of diversity. Application of the diversity indices in soil science have considerably increased in recent years. Taxonomic diversity has been evaluated in the most previous researches whereas comparing the ability of different soil mapping approaches based on these indices was rarely considered. Therefore, the main objective of this study was to compare the ability of the conventional and digital soil maps to explain the soil variability using diversity indices in the Shahrekord plain of

  4. Genetic Variability in Soybean (Glycine max L.) for Low Soil ...

    African Journals Online (AJOL)

    Abush Tesfaye

    1Jimma Research Center, P.O.Box 192, Jimma, Ethiopia, 2Jomo Kenyatta University of and Technology,. Department of Horticulture ... Assessment of the genetic variability of soybean genotypes under low soil phosphorus (P) .... coefficient of variations, broad sense heritability, genetic advance were analyzed using. Genes ...

  5. Soil fauna and its relation with environmental variables in soil management systems

    Directory of Open Access Journals (Sweden)

    Dilmar Baretta

    Full Text Available The present study aims to generate knowledge about the soil fauna, its relation to other explanatory environmental variables, and, besides it, to select edaphic indicators that more contribute to separate the land use systems (LUS. Five different LUS were chosen: conventional tillage with crop rotation (CTCR; no-tillage with crop rotation (NTCR; conventional tillage with crop succession (CTCS; no-tillage with crop succession (NTCS and minimum tillage with crop succession (MTCS. The samples were made in the counties Chapecó, Xanxerê and Ouro Verde located in the state of Santa Catarina, Brazil, and were considered the true replicates of the LUS. In each site, nine points were sampled in a sampling grid of 3 x 3. At the same points, soil was sampled for the physical, chemical and biological attributes (environmental variables. Pitfall traps were used to evaluate the soil fauna. Data were analyzed using principal component analysis (PCA and canonical discriminant analysis (CDA. The soil fauna presented potential to be used as indictors of soil quality, since some groups proved to be sensible to changes of the environmental variables and to soil management and tillage. The soil management using crop rotation (NTCR and CTCR presented higher diversity, compared to the systems using crop succession (NTCS, MTCS and NTCS, evidencing the importance of the soil tillage, independent of the season (summer or winter. The variable that better contributed to explain these changes were the chemical variables (potassium, pH, calcium, organic matter, available phosphorus, potential acidity, and biological variables (Shannon diversity index, Collembola, Pielou equitability index and microbial biomass carbon, respectively.

  6. Soil moisture variability across different scales in an Indian watershed for satellite soil moisture product validation

    KAUST Repository

    Singh, Gurjeet

    2016-05-05

    Strategic ground-based sampling of soil moisture across multiple scales is necessary to validate remotely sensed quantities such as NASA’s Soil Moisture Active Passive (SMAP) product. In the present study, in-situ soil moisture data were collected at two nested scale extents (0.5 km and 3 km) to understand the trend of soil moisture variability across these scales. This ground-based soil moisture sampling was conducted in the 500 km2 Rana watershed situated in eastern India. The study area is characterized as sub-humid, sub-tropical climate with average annual rainfall of about 1456 mm. Three 3x3 km square grids were sampled intensively once a day at 49 locations each, at a spacing of 0.5 km. These intensive sampling locations were selected on the basis of different topography, soil properties and vegetation characteristics. In addition, measurements were also made at 9 locations around each intensive sampling grid at 3 km spacing to cover a 9x9 km square grid. Intensive fine scale soil moisture sampling as well as coarser scale samplings were made using both impedance probes and gravimetric analyses in the study watershed. The ground-based soil moisture samplings were conducted during the day, concurrent with the SMAP descending overpass. Analysis of soil moisture spatial variability in terms of areal mean soil moisture and the statistics of higher-order moments, i.e., the standard deviation, and the coefficient of variation are presented. Results showed that the standard deviation and coefficient of variation of measured soil moisture decreased with extent scale by increasing mean soil moisture. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  7. Spatial variability of chemical properties of soil under pasture

    Directory of Open Access Journals (Sweden)

    Samuel Ferreira da Silva

    2016-04-01

    Full Text Available The objective of this study was to analyze the spatial variability of soil chemical attributes under pasture, as well as lime and fertilizer recommendations based on the interpretation of soil chemical analysis from two sampling methods: conventional and systematic depths of 0 to 10 and 10 to 20 cm. The study was conducted at IFES-campus Alegre-ES. Data analysis was performed using descriptive statistics and geostatistics. Results indicate that the spatial method enabled the identification of deficit areas and excessive liming and fertilization, which could not be defined by the conventional method.

  8. Effects of variability and rate on battery charge storage and lifespan

    Science.gov (United States)

    Krieger, Elena Marie

    The growing prevalence of hybrid and electric vehicles, intermittent renewable energy sources, and other complex power systems has triggered a rapid increase in demand for energy storage. Unlike portable electronic devices, whose batteries can be recharged according to a pre-determined protocol simply by plugging them into the wall, many of these applications are characterized by highly variable charge and demand profiles. The central objective of this work is to assess the impact of power distribution and frequency on battery behavior in order to improve overall system efficiency and lifespan in these variable power applications. We first develop and experimentally verify a model to describe the trade-off between battery charging power and energy stored to assess how varying power input affects battery efficiency. This relationship is influenced both by efficiency losses at high powers and by premature voltage cutoffs, which contribute to incomplete battery charging and discharging. We experimentally study the impact of variable power on battery aging in lead-acid, nickel metal hydride, lithium-ion and lithium iron phosphate batteries. As a case study we focus on off-grid wind systems, and analyze the impact of both power distribution and frequency on charge acceptance and degradation in each of these chemistries. We suggest that lithium iron phosphate batteries may be more suitable for off-grid electrification projects than standard lead-acid batteries. We experimentally assess the impact of additional variable charging parameters on battery performance, including the interplay between efficiency, frequency of power oscillations, state-of-charge, incomplete charging and path dependence. We develop a frequency-domain model for hybrid energy storage systems that couples non-stationary frequency analysis of variable power signals to a frequency-based metric for energy storage device performance. The experimental and modeling work developed herein can be utilized to

  9. Spatial variability of soil salinity in coastal saline soil at different scales in the Yellow River Delta, China.

    Science.gov (United States)

    Wang, Zhuoran; Zhao, Gengxing; Gao, Mingxiu; Chang, Chunyan

    2017-02-01

    The objectives of this study were to explore the spatial variability of soil salinity in coastal saline soil at macro, meso and micro scales in the Yellow River delta, China. Soil electrical conductivities (ECs) were measured at 0-15, 15-30, 30-45 and 45-60 cm soil depths at 49 sampling sites during November 9 to 11, 2013. Soil salinity was converted from soil ECs based on laboratory analyses. Our results indicated that at the macro scale, soil salinity was high with strong variability in each soil layer, and the content increased and the variability weakened with increasing soil depth. From east to west in the region, the farther away from the sea, the lower the soil salinity was. The degrees of soil salinization in three deeper soil layers are 1.14, 1.24 and 1.40 times higher than that in the surface soil. At the meso scale, the sequence of soil salinity in different topographies, soil texture and vegetation decreased, respectively, as follows: depression >flatland >hillock >batture; sandy loam >light loam >medium loam >heavy loam >clay; bare land >suaeda salsa >reed >cogongrass >cotton >paddy >winter wheat. At the micro scale, soil salinity changed with elevation in natural micro-topography and with anthropogenic activities in cultivated land. As the study area narrowed down to different scales, the spatial variability of soil salinity weakened gradually in cultivated land and salt wasteland except the bare land.

  10. Reducing Demand Charges and Onsite Generation Variability Using Behind-the-Meter Energy Storage

    Energy Technology Data Exchange (ETDEWEB)

    Bhattarai, Bishnu P.; Myers, Kurt S.; Bush, Jason W.

    2017-04-01

    Electric utilities in the United States are increasingly employing demand charges and/or real-time pricing. This directive is bringing potential opportunities in deploying behindthe-meter energy storage (BMES) systems for various grid functionalities. This study quantifies techno-economic benefits of BMES in reducing demand charge and smoothing load/generation intermittencies, and determines how those benefits vary with onsite distributed photovoltaic. We proposed a two-stage control algorithm, whereby the first stage proactively determines costoptimal BMES configuration for reducing peak-demands and demand charges, and the second stage adaptively compensates intermittent generations and short load spikes that may otherwise increase the demand charges. The performance of the proposed algorithm is evaluated through a 24 hours time sweep simulation performed using data from smart microgrid testbed at Idaho National Laboratory (INL). The simulation results demonstrated that this research provides a simple but effective solution for peak shaving, demand charge reductions, and smoothing onsite PV variability.

  11. Controls of Soil Spatial Variability in a Dry Tropical Forest.

    Directory of Open Access Journals (Sweden)

    Sandeep Pulla

    Full Text Available We examined the roles of lithology, topography, vegetation and fire in generating local-scale (<1 km2 soil spatial variability in a seasonally dry tropical forest (SDTF in southern India. For this, we mapped soil (available nutrients, Al, total C, pH, moisture and texture in the top 10 cm, rock outcrops, topography, all native woody plants ≥1 cm diameter at breast height (DBH, and spatial variation in fire frequency (times burnt during the 17 years preceding soil sampling in a permanent 50-ha plot. Unlike classic catenas, lower elevation soils had lesser moisture, plant-available Ca, Cu, Mn, Mg, Zn, B, clay and total C. The distribution of plant-available Ca, Cu, Mn and Mg appeared to largely be determined by the whole-rock chemical composition differences between amphibolites and hornblende-biotite gneisses. Amphibolites were associated with summit positions, while gneisses dominated lower elevations, an observation that concurs with other studies in the region which suggest that hillslope-scale topography has been shaped by differential weathering of lithologies. Neither NO3(--N nor NH4(+-N was explained by the basal area of trees belonging to Fabaceae, a family associated with N-fixing species, and no long-term effects of fire on soil parameters were detected. Local-scale lithological variation is an important first-order control over soil variability at the hillslope scale in this SDTF, by both direct influence on nutrient stocks and indirect influence via control of local relief.

  12. Anomalous Threshold Voltage Variability of Nitride Based Charge Storage Nonvolatile Memory Devices

    Directory of Open Access Journals (Sweden)

    Meng Chuan Lee

    2013-01-01

    Full Text Available Conventional technology scaling is implemented to meet the insatiable demand of high memory density and low cost per bit of charge storage nonvolatile memory (NVM devices. In this study, effect of technology scaling to anomalous threshold voltage ( variability is investigated thoroughly on postcycled and baked nitride based charge storage NVM devices. After long annealing bake of high temperature, cell’s variability of each subsequent bake increases within stable distribution and found exacerbate by technology scaling. Apparent activation energy of this anomalous variability was derived through Arrhenius plots. Apparent activation energy (Eaa of this anomalous variability is 0.67 eV at sub-40 nm devices which is a reduction of approximately 2 times from 110 nm devices. Technology scaling clearly aggravates this anomalous variability, and this poses reliability challenges to applications that demand strict control, for example, reference cells that govern fundamental program, erase, and verify operations of NVM devices. Based on critical evidence, this anomalous variability is attributed to lateral displacement of trapped charges in nitride storage layer. Reliability implications of this study are elucidated. Moreover, potential mitigation methods are proposed to complement technology scaling to prolong the front-runner role of nitride based charge storage NVM in semiconductor flash memory market.

  13. Modelling carbon and nitrogen turnover in variably saturated soils

    Science.gov (United States)

    Batlle-Aguilar, J.; Brovelli, A.; Porporato, A.; Barry, D. A.

    2009-04-01

    Natural ecosystems provide services such as ameliorating the impacts of deleterious human activities on both surface and groundwater. For example, several studies have shown that a healthy riparian ecosystem can reduce the nutrient loading of agricultural wastewater, thus protecting the receiving surface water body. As a result, in order to develop better protection strategies and/or restore natural conditions, there is a growing interest in understanding ecosystem functioning, including feedbacks and nonlinearities. Biogeochemical transformations in soils are heavily influenced by microbial decomposition of soil organic matter. Carbon and nutrient cycles are in turn strongly sensitive to environmental conditions, and primarily to soil moisture and temperature. These two physical variables affect the reaction rates of almost all soil biogeochemical transformations, including microbial and fungal activity, nutrient uptake and release from plants, etc. Soil water saturation and temperature are not constants, but vary both in space and time, thus further complicating the picture. In order to interpret field experiments and elucidate the different mechanisms taking place, numerical tools are beneficial. In this work we developed a 3D numerical reactive-transport model as an aid in the investigation the complex physical, chemical and biological interactions occurring in soils. The new code couples the USGS models (MODFLOW 2000-VSF, MT3DMS and PHREEQC) using an operator-splitting algorithm, and is a further development an existing reactive/density-dependent flow model PHWAT. The model was tested using simplified test cases. Following verification, a process-based biogeochemical reaction network describing the turnover of carbon and nitrogen in soils was implemented. Using this tool, we investigated the coupled effect of moisture content and temperature fluctuations on nitrogen and organic matter cycling in the riparian zone, in order to help understand the relative

  14. Comparison of crop stress and soil maps to enhance variable rate irrigation prescriptions

    Science.gov (United States)

    Soil textural variability within many irrigated fields diminishes the effectiveness of conventional irrigation management, and scheduling methods that assume uniform soil conditions may produce less than satisfactory results. Furthermore, benefits of variable-rate application of agrochemicals, seeds...

  15. Spatial and Seasonal Variability of Extreme Soil Temperature in Croatia

    Science.gov (United States)

    Sviličić, Petra; Vučetić, Višnja

    2015-04-01

    In terms of taking the temperature of the Earth in Croatia, first measurements began in 1898 in Križevci, but systematic measurements of soil temperature started in 1951. Today, the measurements are performed at 55 meteorological stations. The process of setting up, calibration, measurement, input, control and data processing is done entirely within the Meteorological and Hydrological Service. Due to the lack of funds, but also as a consequence of the Homeland War, network density in some areas is very rare, leading to aggravating circumstances during analysis. Also, certain temperature series are incomplete or are interrupted and therefore the number of long-term temperature series is very small. This particularly presents problems in coastal area, which is geographically diversified and is very difficult to do a thorough analysis of the area. Using mercury angle geothermometer daily at 7, 14 and 21 h CET, thermal state of soil is measured at 2, 5, 10, 20, 30, 50 and 100 cm depth. Thermometers are placed on the bare ground within the meteorological circle and facing north to reduce the direct impact of solar radiation. Lack of term measurements is noticed in the analysis of extreme soil temperatures, which are not real extreme values, but derived from three observational times. On the basis of fifty year series (1961-2010) at 23 stations, the analysis of trends of the surface maximal and minimal soil temperature, as well as the appearance of freezing is presented. Trends were determined by Sen's slope estimator, and statistical significance on 5% level was determined using the Mann-Kendall test. It was observed that the variability of the surface maximal soil temperature on an annual and seasonal level is much higher than those for surface minimal soil temperature. Trends in the recent period show a statistically significant increase in the maximal soil temperature in the eastern and the coastal regions, especially in the spring and summer season. Also, the

  16. Highly charged swelling mica reduces free and extractable Cu levels in Cu-contaminated soils.

    Science.gov (United States)

    Stuckey, Jason W; Neaman, Alexander; Ravella, Ramesh; Komarneni, Sridhar; Martínez, Carmen Enid

    2008-12-15

    Smelting of copper (Cu) results in the atmospheric deposition of Cu onto surrounding soils. Excess concentrations of Cu in soils can be absorbed by soil biota to toxic levels or leached into the groundwater, threatening the entire ecosystem. A means to restrict Cu mobility and uptake by plants is to remove it from the aqueous phase by applying an adsorptive material. A synthetic clay (highly charged swelling mica) was tested for its ability to decrease the levels of free and 0.1 M KNO3-extractable Cu in 15 surface soils from three different Cu mining areas in central Chile. The soils contained excessive total Cu levels (112-2790 mg Cu (kg soil)(-1)), while extractable Cu ranged from 0.3 to 22.9 mg Cu L(-1). The mica was applied to each soil at rates of 0.1%, 1%, and 2% (w/w). A 2% sodium-montmorillonite treatment and the nonamended soil served as controls. The order of treatment efficacy in reducing extractable Cu and free Cu2+ for low pH soils ( 1% mica > 2% montmorillonite > 0.1% mica. At 120 days, the 2% mica treatment maintained reductions of up to 93% in the free Cu2+ activity and up to 75% in the extractable Cu concentration upon acidification to the original soil pH value. In addition, Cu retention in mica-treated soils was more resistant to acidification than in lime-treated soils. This mica has promise for the remediation of acidic soils with metal contamination at the surface.

  17. Electric Vehicle Routing Problem with Charging Time and Variable Travel Time

    Directory of Open Access Journals (Sweden)

    Sai Shao

    2017-01-01

    Full Text Available An electric vehicle routing problem with charging time and variable travel time is developed to address some operational issues such as range limitation and charging demand. The model is solved by using genetic algorithm to obtain the routes, the vehicle departure time at the depot, and the charging plan. Meanwhile, a dynamic Dijkstra algorithm is applied to find the shortest path between any two adjacent nodes along the routes. To prevent the depletion of all battery power and ensure safe operation in transit, electric vehicles with insufficient battery power can be repeatedly recharged at charging stations. The fluctuations in travel time are implemented to reflect a dynamic traffic environment. In conclusion, a large and realistic case study with a road network in the Beijing urban area is conducted to evaluate the model performance and the solution technology and analyze the results.

  18. Spatio-temporal variability of global soil moisture products

    Science.gov (United States)

    Rötzer, K.; Montzka, C.; Vereecken, H.

    2015-03-01

    Being an important variable for various applications, for example hydrological and weather prediction models or data assimilation, a large range of global soil moisture products from different sources, such as modeling or active and passive microwave remote sensing, are available. The diverse measurement and estimation methods can lead to differences in the characteristics of the products. This study investigates the spatial and temporal behavior of three different products: (i) the Soil Moisture and Ocean Salinity (SMOS) Level 2 product, retrieved with a physically based approach from passive microwave remote sensing brightness temperatures, (ii) the MetOp-A Advanced Scatterometer (ASCAT) product retrieved with a change detection method from radar remote sensing backscattering coefficients, and (iii) the ERA Interim product from a weather forecast model reanalysis. Results show overall similar patterns of spatial soil moisture, but high deviations in absolute values. A ranking of mean relative differences demonstrates that ASCAT and ERA Interim products show most similar spatial soil moisture patterns, while ERA and SMOS products show least similarities. For selected regions in different climate classes, time series of the ASCAT product generally show higher variability of soil moisture than SMOS, and especially than ERA products. The relationship of spatial mean and variance is, especially during wet periods, influenced by sensor and retrieval characteristics in the SMOS product, while it is determined to a larger degree by the precipitation patterns of the respective regions in the ASCAT and ERA products. The decomposition of spatial variance into temporal variant and invariant components exhibits high dependence on the retrieval methods of the respective products. The change detection retrieval method causes higher influence of temporal variant factors (e.g. precipitation, evaporation) on the ASCAT product, while SMOS and ERA products are stronger determined by

  19. Magnitude and Variability of Controllable Charge Capacity Provided by Grid Connected Plug-in Electric Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Scoffield, Don R [Idaho National Lab. (INL), Idaho Falls, ID (United States); Smart, John [Idaho National Lab. (INL), Idaho Falls, ID (United States); Salisbury, Shawn [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    As market penetration of plug-in electric vehicles (PEV) increases over time, the number of PEVs charging on the electric grid will also increase. As the number of PEVs increases, their ability to collectively impact the grid increases. The idea of a large body of PEVs connected to the grid presents an intriguing possibility. If utilities can control PEV charging, it is possible that PEVs could act as a distributed resource to provide grid services. The technology required to control charging is available for modern PEVs. However, a system for wide-spread implementation of controllable charging, including robust communication between vehicles and utilities, is not currently present. Therefore, the value of controllable charging must be assessed and weighed against the cost of building and operating such as system. In order to grasp the value of PEV charge control to the utility, the following must be understood: 1. The amount of controllable energy and power capacity available to the utility 2. The variability of the controllable capacity from day to day and as the number of PEVs in the market increases.

  20. Cosmic ray muon charge ratio derived from the new scaling variable model

    CERN Document Server

    Bhattacharya, D P

    1980-01-01

    The charge ratio of sea level muons has been estimated from the new scaling variable model and the CERN Intersecting Storage Ring data of Capiluppi et al. (1974) for pp to pi /sup +or-/X and pp to K/sup +or- /X inclusive reactions. The estimated muon charge ratio is found to be 1.21 and the result has been compared with the experimental data of Parker et al. (1969), Burnet et al. (1973), Ashley et al., and Muraki et al. (1979). (20 refs).

  1. [Factors influencing the spatial variability in soil respiration under different land use regimes].

    Science.gov (United States)

    Chen, Shu-Tao; Liu, Qiao-Hui; Hu, Zheng-Hua; Liu, Yan; Ren, Jing-Quan; Xie, Wei

    2013-03-01

    In order to investigate the factors influencing the spatial variability in soil respiration under different land use regimes, field experiments were performed. Soil respiration and relevant environment, vegetation and soil factors were measured. The spatial variability in soil respiration and the relationship between soil respiration and these measured factors were investigated. Results indicated that land use regimes had significant effects on soil respiration. Soil respiration varied significantly (P Soil respiration rates ranged from 1.82 to 7.46 micromol x (m2 x s)(-1), with a difference of 5.62 micromol x (m2 x s)(-1) between the highest and lowest respiration rates. Soil organic carbon was a key factor controlling the spatial variability in soil respiration. In all, ecosystems studied, the relationship between soil respiration and soil organic carbon content can be described by a power function. Soil respiration increased with the increase of soil organic carbon. In forest ecosystem, the relationship between soil respiration and diameter at breast height (DBH) of trees can be explained by a natural logarithmic function. A model composed of soil organic carbon (C, %), available phosphorous (AP, g x kg(-1)) and diameter at breast height (DBH, cm) explained 92.8% spatial variability in soil respiration for forest ecosystems.

  2. Spatial variability of soil aggregate stability at the scale of an agricultural region in Tunisia

    OpenAIRE

    Annabi, M.; Raclot, Damien; Bahri, H.; Bailly, J. S.; Gomez, Cécile; Le Bissonnais, Y.

    2017-01-01

    International audience; Soil aggregate stability is a key factor in soil resistance to water erosion, which is a threat to soils in a large part of northern Tunisia. The analysis of the spatial variability of soil aggregate stability provides both agronomic and environmentally useful information. However, extensive measurements of soil aggregate stability remain tedious and expensive. This study explores two different approaches as alternative to measurements of soil aggregate stability. One ...

  3. Landscape controls and vertical variability of soil organic carbon storage in permafrost-affected soils of the Lena River Delta

    DEFF Research Database (Denmark)

    Siewert, Matthias Benjamin; Hugelius, Gustaf; Heim, Birgit

    2016-01-01

    results show that the geomorphological setting explains more soil variability than soil taxonomy classes or vegetation cover. The soils from the oldest, Pleistocene aged, unit of the delta store the highest amount of SOC per m2 followed by the Holocene river terrace. The Pleistocene terrace affected...

  4. Associations between soil variables and vegetation structure and composition of Caribbean dry forests

    Science.gov (United States)

    Elvia M. Melendez-Ackerman; Julissa Rojas-Sandoval; Danny S. Fernandez; Grizelle Gonzalez; Hana Lopez; Jose Sustache; Mariely Morales; Miguel Garcia-Bermudez; Susan Aragon

    2016-01-01

    Soil–vegetation associations have been understudied in tropical dry forests when compared to the amount of extant research on this issue in tropical wet forests. Recent studies assert that vegetation in tropical dry forests is highly heterogeneous and that soil variability may be a contributing factor. In this study, we evaluated the relationship between soil variables...

  5. Statistical analyses of variability in properties of soils in gully erosion ...

    African Journals Online (AJOL)

    The study involved the statistical analyses of variability of soil with depth and its influence on gully development. The soil data were obtained from field study and laboratory analyses. The statistical analyses of soil data were performed on soil index properties using Statistical Package for Social Sciences. Results of the ...

  6. Spatial and Temporal Variability of Soil Respiration Fluxes from Alpine and Subalpine Soils in the East River Watershed, Colorado

    Science.gov (United States)

    McCormick, M. E.; Winnick, M.; Rainaldi, G. R.; Lawrence, C. R.; Druhan, J. L.; Hsu, H. T.; Maher, K.

    2016-12-01

    Soil respiration of carbon to the atmosphere represents one of the largest fluxes of the terrestrial carbon cycle and is sensitive to changes in temperature, soil moisture, and processes affecting carbon stability. Despite the importance of these sensitivities, few studies have examined the spatial and temporal heterogeneity of soil CO2 fluxes and their controls on intermediate- to large-scale integrated soil fluxes. In this study, we examine spatial variability at scales of 10-5 -101 km2 and temporal variability at scales of hours to months of soil CO2 fluxes through the 2016 growing season in the East River Watershed, CO. We present analyses of (1) temporal variability of CO2 fluxes from four locations with depth-resolved temperature, moisture content, soil gas pCO2, and soil carbon content measurements; (2) spatial variability of CO2 fluxes and surface soil water content across a gridded hillslope with 74 points over an area of 2.5 x 10-3 km2 measured at multiple times throughout the growing season; and (3) variability of CO2 fluxes and surface soil water content from >20 point locations across the 85 km2 catchment targeting a range of vegetation, slope, and aspect characteristics. Comparing soil CO2 fluxes with depth-resolved temperature, moisture, pCO2 and carbon content, we calculate depth-resolved CO2 production rates and their correlations with soil conditions. Gridded hillslope flux measurements reveal strong and consistent variability across separation distances of 1 - 30 m with a slight dependence on slope position, likely representing the controls of lateral flow on soil moisture content. Finally, we analyze correlations of soil CO2 fluxes from point measurements representing broad-scale landscape units with vegetation and geomorphological characteristics. Combining these observations, we examine the implications of our results for interpolating point flux measurements to the catchment scale and for calculating integrated fluxes through the growing

  7. Highly charged swelling mica reduces Cu bioavailability in Cu-contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Stuckey, Jason W. [Department of Crop and Soil Sciences, Pennsylvania State University, 116 ASI Building, University Park, PA 16802 (United States); Neaman, Alexander [Facultad de Agronomia, P. Universidad Catolica de Valparaiso, Centro Regional de Estudios en Alimentos Saludables (Chile); Ravella, Ramesh; Komarneni, Sridhar [Department of Crop and Soil Sciences, Pennsylvania State University, 116 ASI Building, University Park, PA 16802 (United States); Martinez, Carmen Enid [Department of Crop and Soil Sciences, Pennsylvania State University, 116 ASI Building, University Park, PA 16802 (United States)], E-mail: cem17@psu.edu

    2009-01-15

    This is the first test of a highly charged swelling mica's (Na-2-mica) ability to reduce the plant-absorbed Cu in Cu-contaminated soils from Chile. Perennial ryegrass (Lolium perenne L.) was grown in two acid soils (Sector 2: pH 4.2, total Cu = 172 mg Cu kg{sup -1} and Sector 3: pH 4.2, total Cu = 112 mg Cu kg{sup -1}) amended with 0.5% and 1% (w/w) mica, and 1% (w/w) montmorillonite. At 10 weeks of growth, both mica treatments decreased the shoot Cu of ryegrass grown in Sector 2 producing shoot Cu concentrations above 21-22 mg Cu kg{sup -1} (the phytotoxicity threshold for that species), yet the mica treatments did not reduce shoot Cu concentrations when grown in Sector 3, which were at a typical level. The mica treatments improved shoot growth in Sector 3 by reducing free and extractable Cu to low enough levels where other nutrients could compete for plant absorption and translocation. In addition, the mica treatments improved root growth in both soils, and the 1% mica treatment reduced root Cu in both soils. This swelling mica warrants further testing of its ability to assist re-vegetation and reduce Cu bioavailability in Cu-contaminated surface soils. - In situ remediation of Cu-contaminated soils with a synthetic mica (Na-2-mica) will aid in re-vegetative efforts.

  8. VARIABILITY OF ARABLE AND FOREST SOILS PROPERTIES ON ERODED SLOPES

    Directory of Open Access Journals (Sweden)

    Paweł Wiśniewski

    2014-10-01

    Full Text Available The basic method of reducing soil and land erosion is a change of land use, for example, from arable to forest. Particularly effective as a protective role – according to the Polish law – soil-protecting forests. The thesis presents differences in the deformation of the basic soil properties on moraine slopes, depending on land use. There has been presented the function and the efficiency of the soil-protecting forests in erosion control. The soil cross section transects and soil analysis displayed that soil-protecting forests are making an essential soil cover protection from degradation, inter alia, limiting the decrease of humus content, reduction of upper soil horizons and soil pedons layer. On the afforested slopes it was stated some clear changes of grain size and chemical properties of soils in relation to adjacent slopes agriculturally used.

  9. Factor analysis of soil spatial variability in gully erosion area of ...

    African Journals Online (AJOL)

    The effect of soil characteristics on gully development and distribution has made it desirable to determine the spatial variability of its physical and chemical properties. This paper examines the spatial variability of soil properties and factors contributing to the general pattern of variability in Agulu- Nanka- Oko gully complex, ...

  10. Spatial variability of soil available phosphorous and potassium at three different soils located in Pannonian Croatia

    Science.gov (United States)

    Bogunović, Igor; Pereira, Paulo; Đurđević, Boris

    2017-04-01

    Information on spatial distribution of soil nutrients in agroecosystems is critical for improving productivity and reducing environmental pressures in intensive farmed soils. In this context, spatial prediction of soil properties should be accurate. In this study we analyse 704 data of soil available phosphorus (AP) and potassium (AK); the data derive from soil samples collected across three arable fields in Baranja region (Croatia) in correspondence of different soil types: Cambisols (169 samples), Chernozems (131 samples) and Gleysoils (404 samples). The samples are collected in a regular sampling grid (distance 225 x 225 m). Several geostatistical techniques (Inverse Distance to a Weight (IDW) with the power of 1, 2 and 3; Radial Basis Functions (RBF) - Inverse Multiquadratic (IMT), Multiquadratic (MTQ), Completely Regularized Spline (CRS), Spline with Tension (SPT) and Thin Plate Spline (TPS); and Local Polynomial (LP) with the power of 1 and 2; two geostatistical techniques -Ordinary Kriging - OK and Simple Kriging - SK) were tested in order to evaluate the most accurate spatial variability maps using criteria of lowest RMSE during cross validation technique. Soil parameters varied considerably throughout the studied fields and their coefficient of variations ranged from 31.4% to 37.7% and from 19.3% to 27.1% for soil AP and AK, respectively. The experimental variograms indicate a moderate spatial dependence for AP and strong spatial dependence for all three locations. The best spatial predictor for AP at Chernozem field was Simple kriging (RMSE=61.711), and for AK inverse multiquadratic (RMSE=44.689). The least accurate technique was Thin plate spline (AP) and Inverse distance to a weight with a power of 1 (AK). Radial basis function models (Spline with Tension for AP at Gleysoil and Cambisol and Completely Regularized Spline for AK at Gleysol) were the best predictors, while Thin Plate Spline models were the least accurate in all three cases. The best

  11. Spatial Variability and Geostatistical Prediction of Some Soil Hydraulic Coefficients of a Calcareous Soil

    Directory of Open Access Journals (Sweden)

    Ali Akbar Moosavi

    2017-02-01

    Full Text Available Introduction: Saturated hydraulic conductivity and the other hydraulic properties of soils are essential vital soil attributes that play role in the modeling of hydrological phenomena, designing irrigation-drainage systems, transportation of salts and chemical and biological pollutants within the soil. Measurement of these hydraulic properties needs some special instruments, expert technician, and are time consuming and expensive and due to their high temporal and spatial variability, a large number of measurements are needed. Nowadays, prediction of these attributes using the readily available soil data using pedotransfer functions or using the limited measurement with applying the geostatistical approaches has been receiving high attention. The study aimed to determine the spatial variability and prediction of saturated (Ks and near saturated (Kfs hydraulic conductivity, the power of Gardner equation (α, sorptivity (S, hydraulic diffusivity (D and matric flux potential (Фm of a calcareous soil. Material and Methods: The study was carried out on the soil series of Daneshkadeh located in the Bajgah Agricultural Experimental Station of Agricultural College, Shiraz University, Shiraz, Iran (1852 m above the mean sea level. This soil series with about 745 ha is a deep yellowish brow calcareous soil with textural classes of loam to clay. In the studied soil series 50 sampling locations with the sampling distances of 16, 8 , and 4 m were selected on the relatively regular sampling design. The saturated hydraulic conductivity (Ks, near saturated hydraulic conductivity (Kfs, the power of Gardner equation (α, sorptivity (S, hydraulic diffusivity (D and matric flux potential (Фm of the aforementioned sampling locations was determined using the Single Ring and Droplet methods. After, initial statistical processing, including a normality test of data, trend and stationary analysis of data, the semivariograms of each studied hydraulic attributes were

  12. Generalized Density-Corrected Model for Gas Diffusivity in Variably Saturated Soils

    DEFF Research Database (Denmark)

    Chamindu, Deepagoda; Møldrup, Per; Schjønning, Per

    2011-01-01

    models. The GDC model was further extended to describe two-region (bimodal) soils and could describe and predict Dp/Do well for both different soil aggregate size fractions and variably compacted volcanic ash soils. A possible use of the new GDC model is engineering applications such as the design......Accurate predictions of the soil-gas diffusivity (Dp/Do, where Dp is the soil-gas diffusion coefficient and Do is the diffusion coefficient in free air) from easily measureable parameters like air-filled porosity (ε) and soil total porosity (φ) are valuable when predicting soil aeration...... and the emission of greenhouse gases and gaseous-phase contaminants from soils. Soil type (texture) and soil density (compaction) are two key factors controlling gas diffusivity in soils. We extended a recently presented density-corrected Dp(ε)/Do model by letting both model parameters (α and β) be interdependent...

  13. Geochemical variability of soils and biogeochemical variability of plants in the Piceance Basin, Colorado

    Science.gov (United States)

    Tuttle, M.L.; Severson, R.C.; Dean, W.E.; Klusman, R.W.

    1986-01-01

    , and DTPA-extractable boron, copper, iron, magnesium, and nickel have lower concentrations in topsoil than in the spent oil shale; whereas, silicon, titanium, ytterbium, clay, quartz, and DTPA-extractable potassium have greater concentrations in the topsoil than in the spent oil shale. In western wheatgrass, molybdenum has a lower concentration in grasses growing on the topsoil than in grasses on the spent oil shale; whereas, barium, calcium, manganese, strontium, zinc, and ash have greater concentrations in grasses growing on the topsoil than on the spent oil shale. When compared to baseline values, soils in the revegetation plot are significantly higher in concentrations of lead, zinc, organic and total carbon, and DTP A-extractable cadmium, iron, manganese, nickel, phosphorus, and zinc. Whereas, western wheatgrass grown within the revegetation plot has concentrations which fall within the baseline values established in the regional study. The equations used in predicting concentrations of elements in plants from native and altered sites are cumbersome because of the large number of variables required to adequately predict expected concentrations and are of limited use because many explained only a small proportion of the total variation.

  14. Climate, soil or both? Which variables are better predictors of the distributions of Australian shrub species?

    Science.gov (United States)

    Hageer, Yasmin; Esperón-Rodríguez, Manuel; Baumgartner, John B; Beaumont, Linda J

    2017-01-01

    Shrubs play a key role in biogeochemical cycles, prevent soil and water erosion, provide forage for livestock, and are a source of food, wood and non-wood products. However, despite their ecological and societal importance, the influence of different environmental variables on shrub distributions remains unclear. We evaluated the influence of climate and soil characteristics, and whether including soil variables improved the performance of a species distribution model (SDM), Maxent. This study assessed variation in predictions of environmental suitability for 29 Australian shrub species (representing dominant members of six shrubland classes) due to the use of alternative sets of predictor variables. Models were calibrated with (1) climate variables only, (2) climate and soil variables, and (3) soil variables only. The predictive power of SDMs differed substantially across species, but generally models calibrated with both climate and soil data performed better than those calibrated only with climate variables. Models calibrated solely with soil variables were the least accurate. We found regional differences in potential shrub species richness across Australia due to the use of different sets of variables. Our study provides evidence that predicted patterns of species richness may be sensitive to the choice of predictor set when multiple, plausible alternatives exist, and demonstrates the importance of considering soil properties when modeling availability of habitat for plants.

  15. Spatial and Temporal Variability of Soil CO2 Flux in Sugarcane Green Harvest Systems

    Directory of Open Access Journals (Sweden)

    Rose Luiza Moraes Tavares

    2016-01-01

    Full Text Available ABSTRACT The sugarcane green harvest system, characterized by mechanized harvesting and the absence of crop burning, affects soil quality by increasing crop residue on the soil surface after harvest; thus, it contributes to improving the physical, chemical, and microbiological properties and influences the soil carbon content and CO2 flux (FCO2. This study aimed to evaluate the spatial and temporal variability of soil FCO2 in sugarcane green harvest systems. The experiment was conducted in two areas of sugarcane in São Paulo, Brazil: the first had a 5-year history of sugarcane green harvest (SG-5 and the second had a longer history of 10 years (SG-10. The temporal FCO2 were evaluated in the dry and rainy periods, and spatial variability in the dry period, and related to soil chemical and physical properties, including organic C porosity, bulk density, soil penetration resistance, mean weight diameter of soil aggregates, clay, P, S, Ca, Mg and Fe. The temporal variability indicated no differences between the dry and rainy periods in SG-10, while in SG-5 soil moisture was increased by 33 % in the rainy period. The spatial variability indicated a different pattern from the temporal one, where FCO2 in SG-10 was correlated with soil temperature, air-filled pore space, total porosity, soil moisture, and the Ca and Mg contents; in the SG-5 area, FCO2 was correlated with soil mean weight diameter of soil aggregates and the sulfur content.

  16. Nitrate and dissolved organic carbon mobilization in response to soil freezing variability

    Science.gov (United States)

    Colin B. Fuss; Charles T. Driscoll; Peter M. Groffman; John L. Campbell; Lynn M. Christenson; Timothy J. Fahey; Melany C. Fisk; Myron J. Mitchell; Pamela H. Templer; Jorge Durán; Jennifer L. Morse

    2016-01-01

    Reduced snowpack and associated increases in soil freezing severity resulting from winter climate change have the potential to disrupt carbon (C) and nitrogen (N) cycling in soils. We used a natural winter climate gradient based on elevation and aspect in a northern hardwood forest to examine the effects of variability in soil freezing depth, duration, and frequency on...

  17. Spatial Variability of Particle Sizes of Coastal Plain Sands Soils of ...

    African Journals Online (AJOL)

    ... assess the extent of variability, spatial dependence and structure of soil particle sizes, pedological and management implications in the coastal plain sands soils of southeastern Nigeria. Surface (0 – 15cm) and subsurface (15 – 30cm) soil samples were collected at 10m2 intervals (rigid grid nodes) in a 100m by 100m plot ...

  18. Variability of soil moisture and its relationship with surface albedo ...

    Indian Academy of Sciences (India)

    α. Surface albedo. Su. Reflected solar radiation (W/m. 2. ) Sd. Total downward solar radiation. (W/m. 2. ) T. Soil temperature (. ◦. C) k. Soil thermal diffusivity (m. 2 s. −1. ) ... Soil moisture; rainfall; surface albedo; solar elevation angle; thermal diffusivity; atmospheric sciences; ... the diurnal, monthly and seasonal variations of.

  19. Moisture variability resulting from water repellency in Dutch soils

    NARCIS (Netherlands)

    Dekker, L.W.

    1998-01-01

    The present study suggests that many soils in the Netherlands, in natural as well as in agricultural areas, may be water repellent to some degree, challenging the common perception that soil water repellency is only an interesting aberration. When dry, water repellent soils resist or retard

  20. Variability in urban soils influences the health and growth of native tree seedlings

    Science.gov (United States)

    Clara C. Pregitzer; Nancy F. Sonti; Richard A. Hallett

    2016-01-01

    Reforesting degraded urban landscapes is important due to the many benefits urban forests provide. Urban soils are highly variable, yet little is known about how this variability in urban soils influences tree seedling performance and survival. We conducted a greenhouse study to assess health, growth, and survival of four native tree species growing in native glacial...

  1. Investigation of Hillslope-Scale Soil Moisture Spatial and Temporal Variability

    Science.gov (United States)

    Martini, E.; Kögler, S.; Wollschlaeger, U.; Zacharias, S.; Werban, U.; Dietrich, P.

    2013-12-01

    Soil moisture is a key state variable that controls hydrological and energy fluxes at various spatial and temporal scales. Understanding and characterizing this variability is one of the major challenges within hydrological sciences. Understanding soil moisture dynamics at the hillslope scale is important to link point- and catchment-scale studies, and for up- and down-scaling of hydrological processes. Nevertheless, deriving generalizable process understanding is not trivial, because of the non-linearity of hillslope response to rainfall. The overall aim of this work was to describe the soil moisture variability at different spatial and temporal scales within a hillslope area with varying topography and soil type but homogeneous land use. Recent developments of wireless sensor technology allow for the long-term monitoring of soil water content with high spatial and temporal resolution, hence facilitate a better understanding of soil moisture spatial variability and the related hydrological processes. Geophysical techniques such as electromagnetic induction (EMI) methods have been widely used during the last decades to map soil properties at the field scale, because of their suitability for fast and precise mapping of soil apparent electrical conductivity (ECa) over large areas. In the Harz Mountains (Central Germany), a 2.5 ha hillslope area was permanently instrumented with a wireless soil moisture and soil temperature monitoring network (SoilNet). It comprises 40 measurement nodes, and 30 of them were located according to a geostatitstical sampling strategy based on ancillary information. At each of the network nodes, 6 sensors measure hourly the soil water content and soil temperature at three depths within the vadose zone. Time-lapse EMI measurements were carried out to map spatial patterns of ECa over several depths. The one-year high-resolution SoilNet time-series is described, and the soil moisture spatial variability is discussed.

  2. Relevance of anisotropy and spatial variability of gas diffusivity for soil-gas transport

    Science.gov (United States)

    Schack-Kirchner, Helmer; Kühne, Anke; Lang, Friederike

    2017-04-01

    Models of soil gas transport generally do not consider neither direction dependence of gas diffusivity, nor its small-scale variability. However, in a recent study, we could provide evidence for anisotropy favouring vertical gas diffusion in natural soils. We hypothesize that gas transport models based on gas diffusion data measured with soil rings are strongly influenced by both, anisotropy and spatial variability and the use of averaged diffusivities could be misleading. To test this we used a 2-dimensional model of soil gas transport to under compacted wheel tracks to model the soil-air oxygen distribution in the soil. The model was parametrized with data obtained from soil-ring measurements with its central tendency and variability. The model includes vertical parameter variability as well as variation perpendicular to the elongated wheel track. Different parametrization types have been tested: [i)]Averaged values for wheel track and undisturbed. em [ii)]Random distribution of soil cells with normally distributed variability within the strata. em [iii)]Random distributed soil cells with uniformly distributed variability within the strata. All three types of small-scale variability has been tested for [j)] isotropic gas diffusivity and em [jj)]reduced horizontal gas diffusivity (constant factor), yielding in total six models. As expected the different parametrizations had an important influence to the aeration state under wheel tracks with the strongest oxygen depletion in case of uniformly distributed variability and anisotropy towards higher vertical diffusivity. The simple simulation approach clearly showed the relevance of anisotropy and spatial variability in case of identical central tendency measures of gas diffusivity. However, until now it did not consider spatial dependency of variability, that could even aggravate effects. To consider anisotropy and spatial variability in gas transport models we recommend a) to measure soil-gas transport parameters

  3. On the variably-charged black holes in general relativity: Hawking's radiation and naked singularities

    CERN Document Server

    Ibohal, N

    2002-01-01

    In this paper variably-charged non-rotating Reissner-Nordstrom and rotating Kerr-Newman black holes are discussed. Such a variable charge e with respect to the polar coordinate r in the field equations is referred to as an electrical radiation of the black hole. It is shown that every electrical radiation e(r) of the non-rotating black hole leads to a reduction in its mass M by some quantity. If one considers such electrical radiation taking place continuously for a long time, then a continuous reduction of the mass may take place in the black-hole body and the original mass of the black hole may be evaporated completely. At that stage, the gravity of the object may depend only on the electromagnetic field, not on the mass. Immediately after the complete evaporation of the mass, if the next radiation continues, there may be creation of a new mass leading to the formation of a negative mass naked singularity. It appears that this new mass of the naked singularity would never decrease, but might increase gradua...

  4. Small Scale Spatial Variability of Soil Properties and Nutrients in a Ferralsol under Corn

    Science.gov (United States)

    Alves, M. C.; Vidal Vázquez, E.; Pereira de Almeida, V.; Paz-Ferreiro, J.

    2012-04-01

    Spatial variability of soil attributes, both in natural and agricultural landscapes can be rather large. This heterogeneity results from interactions between pedogenetic processes and soil formation factors. In cultivated soils much variability can also occur as a result of land use and management effect, i.e. agricultural systems and practices. Therefore, the main objectives of this work were to investigate the statistical and geostatistical variability of selected properties in a soil cultivated with corn. The experimental work was carried out in Ilha Solteira, São Paulostate, Brazil and the soil was classified as an Oxisol (SSA), i.e. "Latossolo Vermelho" according to the Brazilian Soil Classification System. Eighty-four soil samples were collected at each of two different depths (0-10 and 10-20 cm) from the one-hectare plot studied. Sampling included a combination of grid and nesting schemes in order to allow description of the spatial variability at different scales. Soil texture fractions (sand, silt clay), organic matter content and pH (CaCl2) were determined using standard methods. Moreover, exchangeable bases (Ca, Mg, K), cation exchange capacity (CEC) and P were determined after exchange resin extraction. In the two depths studied, extractable P, K and Mg contents were found to be highly variable (C.V. > 30%), organic matter content and CEC showed a medium variability (C.V. ≈ 15-30%) and base percent saturation and pH exhibited a low variation (map the spatial variability of the study properties. Semivariograms provided a description of the pattern of spatial variability and some insight into possible process affecting the spatial distribution of the assessed soil properties. Sensitivity of nutrient spatial requirements to between field variability was discussed on the basis of the results obtained. In addition, the usefulness of kriging maps to improve and optimize productivity of this soil under intensive agricultural land use was considered.

  5. Variability of soil moisture and its relationship with surface albedo ...

    Indian Academy of Sciences (India)

    Continuous observation data collected over the year 2008 at Astronomical Observatory, Thiruvananthapuram in south Kerala (76° 59′E longitude and 8° 30′N latitude) are used to study the diurnal, monthly and seasonal soil moisture variations. The effect of rainfall on diurnal and seasonal soil moisture is discussed.

  6. Soil fertility assessment and mapping of spatial variability at ...

    African Journals Online (AJOL)

    Information on soil fertility assessment and mapping of arable land helps to design appropriate soil fertility management practices. Experiment was conducted at ... Exchangeable Ca and Mg ranged from 9.25 (LU 4) to 23.35 cmol (+) kg-1 (LU 2) and 2.76 (LU 5) to 8.50 cmol (+) kg-1 (LU 3), respectively. The highest (76.86%) ...

  7. Spatial variability of expansive soil properties at different scales ...

    African Journals Online (AJOL)

    This paper applies statistical and geostatistical procedures to analyse the spatial distribution of several soil properties and use the contribution of ge ostatistics to plan optimal soil sampling and management schemes in. Kibaha, Tanzania. Particle-size distribution, Atterberg limits and potential swell were analysed.

  8. Spatial Variability of Soil Morphorlogical and Physico- Chemical ...

    African Journals Online (AJOL)

    user

    for optimum and sustainable agriculture. (Wilding, 1985). Variation in soil properties imposed limitation on the potentiality of the soil and productivity status. ... The samples were air dried ground and sieved to separate the fine earth particle fraction (less than 2 mm) from coarse fragments using ceramic mortar and pestle.

  9. A Simple Model of the Variability of Soil Depths

    Directory of Open Access Journals (Sweden)

    Fang Yu

    2017-06-01

    Full Text Available Soil depth tends to vary from a few centimeters to several meters, depending on many natural and environmental factors. We hypothesize that the cumulative effect of these factors on soil depth, which is chiefly dependent on the process of biogeochemical weathering, is particularly affected by soil porewater (i.e., solute transport and infiltration from the land surface. Taking into account evidence for a non-Gaussian distribution of rock weathering rates, we propose a simple mathematical model to describe the relationship between soil depth and infiltration flux. The model was tested using several areas in mostly semi-arid climate zones. The application of this model demonstrates the use of fundamental principles of physics to quantify the coupled effects of the five principal soil-forming factors of Dokuchaev.

  10. The variability of standard artificial soils: Behaviour, extractability and bioavailability of organic pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Hofman, Jakub, E-mail: hofman@recetox.muni.cz [Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Kamenice 753/5, Brno CZ-62500 (Czech Republic); Hovorková, Ivana [Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Kamenice 753/5, Brno CZ-62500 (Czech Republic); Semple, Kirk T. [Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom)

    2014-01-15

    Highlights: • Artificial soils from different laboratories revealed different fates, behaviour and bioavailability of lindane and phenanthrene. • Lindane behaviour was related to organic carbon. • Phenanthrene behaviour was significantly affected by degrading microorganisms from peat. • Sterilization of artificial soils might reduce unwanted variability. -- Abstract: Artificial soil is an important standard medium and reference material for soil ecotoxicity bioassays. Recent studies have documented the significant variability of their basic properties among different laboratories. Our study investigated (i) the variability of ten artificial soils from different laboratories by means of the fate, extractability and bioavailability of phenanthrene and lindane, and (ii) the relationships of these results to soil properties and ageing. Soils were spiked with {sup 14}C-phenanthrene and {sup 14}C-lindane, and the total residues, fractions extractable by hydroxypropyl-β-cyclodextrin, and the fractions of phenanthrene mineralizable by bacteria were determined after 1, 14, 28 and 56 days. Significant temporal changes in total residues and extractable and mineralizable fractions were observed for phenanthrene, resulting in large differences between soils after 56 days. Phenanthrene mineralization by indigenous peat microorganisms was suggested as the main driver of that, outweighing the effects of organic matter. Lindane total residues and extractability displayed much smaller changes over time and smaller differences between soils related to organic matter. Roughly estimated, the variability between the artificial soils was comparable to natural soils. The implications of such variability for the results of toxicity tests and risk assessment decisions should be identified. We also suggested that the sterilization of artificial soils might reduce unwanted variability.

  11. [Effects of variable temperature on organic carbon mineralization in typical limestone soils].

    Science.gov (United States)

    Wang, Lian-Ge; Gao, Yan-Hong; Ding, Chang-Huan; Ci, En; Xie, De-Ti

    2014-11-01

    Soil sampling in the field and incubation experiment in the laboratory were conducted to investigate the responses of soil organic carbon (SOC) mineralization to variable temperature regimes in the topsoil of limestone soils from forest land and dry land. Two incubated limestone soils were sampled from the 0-10 cm layers of typical forest land and dry land respectively, which were distributed in Tianlong Mountain area of Puding county, Guizhou province. The soils were incubated for 56 d under two different temperature regimes including variable temperature (range: 15-25 degrees C, interval: 12 h) and constant temperature (20 degrees C), and the cumulative temperature was the same in the two temperature treatments. In the entire incubation period (56 d), the SOC cumulative mineralization (63.32 mg x kg(-1)) in the limestone soil from dry land (SH) under the variable temperature was lower than that (63.96 mg x kg(-1)) at constant 20 degrees C, and there was no significant difference in the SOC cumulative mineralization between the variable and constant temperature treatments (P variable temperature was significantly lower than that (209.52 mg x kg(-1)) at constant 20 degrees C. The results indicated that the responses of SOC mineralization to the variable temperature were obviously different between SL and SH soils. The SOC content and composition were significantly different between SL and SH soils affected by vegetation and land use type, which suggested that SOC content and composition were important factors causing the different responses of SOC mineralization to variable temperature between SL and SH soils. In addition, the dissolved organic carbon (DOC) content of two limestone soils were highly (P variable temperature mainly influenced SOC mineralization by changing microbial community activity rather than by changing microbial quantity.

  12. Modeling Short-Range Soil Variability and its Potential Use in Variable-Rate Treatment of Experimental Plots

    Directory of Open Access Journals (Sweden)

    A Moameni

    2011-02-01

    Full Text Available Abstract In Iran, the experimental plots under fertilizer trials are managed in such a way that the whole plot area uniformly receives agricultural inputs. This could lead to biased research results and hence to suppressing of the efforts made by the researchers. This research was conducted in a selected site belonging to the Gonbad Agricultural Research Station, located in the semiarid region, northeastern Iran. The aim was to characterize the short-range spatial variability of the inherent and management-depended soil properties and to determine if this variation is large and can be managed at practical scales. The soils were sampled using a grid 55 m apart. In total, 100 composite soil samples were collected from topsoil (0-30 cm and were analyzed for calcium carbonate equivalent, organic carbon, clay, available phosphorus, available potassium, iron, copper, zinc and manganese. Descriptive statistics were applied to check data trends. Geostatistical analysis was applied to variography, model fitting and contour mapping. Sampling at 55 m made it possible to split the area of the selected experimental plot into relatively uniform areas that allow application of agricultural inputs with variable rates. Keywords: Short-range soil variability, Within-field soil variability, Interpolation, Precision agriculture, Geostatistics

  13. Mapping spatial variability of soil salinity in a coastal paddy field based on electromagnetic sensors.

    Science.gov (United States)

    Guo, Yan; Huang, Jingyi; Shi, Zhou; Li, Hongyi

    2015-01-01

    In coastal China, there is an urgent need to increase land area for agricultural production and urban development, where there is a rapid growing population. One solution is land reclamation from coastal tidelands, but soil salinization is problematic. As such, it is very important to characterize and map the within-field variability of soil salinity in space and time. Conventional methods are often time-consuming, expensive, labor-intensive, and unpractical. Fortunately, proximal sensing has become an important technology in characterizing within-field spatial variability. In this study, we employed the EM38 to study spatial variability of soil salinity in a coastal paddy field. Significant correlation relationship between ECa and EC1:5 (i.e. r >0.9) allowed us to use EM38 data to characterize the spatial variability of soil salinity. Geostatistical methods were used to determine the horizontal spatio-temporal variability of soil salinity over three consecutive years. The study found that the distribution of salinity was heterogeneous and the leaching of salts was more significant in the edges of the study field. By inverting the EM38 data using a Quasi-3D inversion algorithm, the vertical spatio-temporal variability of soil salinity was determined and the leaching of salts over time was easily identified. The methodology of this study can be used as guidance for researchers interested in understanding soil salinity development as well as land managers aiming for effective soil salinity monitoring and management practices. In order to better characterize the variations in soil salinity to a deeper soil profile, the deeper mode of EM38 (i.e., EM38v) as well as other EMI instruments (e.g. DUALEM-421) can be incorporated to conduct Quasi-3D inversions for deeper soil profiles.

  14. Mapping spatial variability of soil salinity in a coastal paddy field based on electromagnetic sensors.

    Directory of Open Access Journals (Sweden)

    Yan Guo

    Full Text Available In coastal China, there is an urgent need to increase land area for agricultural production and urban development, where there is a rapid growing population. One solution is land reclamation from coastal tidelands, but soil salinization is problematic. As such, it is very important to characterize and map the within-field variability of soil salinity in space and time. Conventional methods are often time-consuming, expensive, labor-intensive, and unpractical. Fortunately, proximal sensing has become an important technology in characterizing within-field spatial variability. In this study, we employed the EM38 to study spatial variability of soil salinity in a coastal paddy field. Significant correlation relationship between ECa and EC1:5 (i.e. r >0.9 allowed us to use EM38 data to characterize the spatial variability of soil salinity. Geostatistical methods were used to determine the horizontal spatio-temporal variability of soil salinity over three consecutive years. The study found that the distribution of salinity was heterogeneous and the leaching of salts was more significant in the edges of the study field. By inverting the EM38 data using a Quasi-3D inversion algorithm, the vertical spatio-temporal variability of soil salinity was determined and the leaching of salts over time was easily identified. The methodology of this study can be used as guidance for researchers interested in understanding soil salinity development as well as land managers aiming for effective soil salinity monitoring and management practices. In order to better characterize the variations in soil salinity to a deeper soil profile, the deeper mode of EM38 (i.e., EM38v as well as other EMI instruments (e.g. DUALEM-421 can be incorporated to conduct Quasi-3D inversions for deeper soil profiles.

  15. Assessment of some soil properties by spatial variability in saline and sodic soils in Arsanjan plain, Southern Iran.

    Science.gov (United States)

    Emadi, Mostafa; Baghernejad, Majid; Emadi, Mehdi; Maftoun, Manouchehr

    2008-01-15

    Spatial patterns for several soil parameters such soil texture, Exchangeable Sodium Percentage (ESP), Electrical Conductivity (ECe), soil pH, Cation Exchange Capacity (CEC) were examined in saline and sodic soils in Arsanjan plain, Southern Iran, in order to identify their spatial distribution for implementation of a site-specific management. Soil samples were collected from 0-30, 30-60 and 60-90 cm soil depths at 85 sampling sites. Data were analyzed both statistically and geostatistically on the basis of the semivariogram. The spatial distribution model and spatial dependence level varied between soil parameters. Soil pH and ESP had the minimum and maximum variability at all depths, respectively. Soil properties indicated moderate to strong spatial dependence. ECe exhibited moderate spatial dependence at three depths; pH and ESP had a moderate spatial dependence at 0-30 cm and strong spatial dependence at 30-60 and 60-90 cm depths. Clay and CEC exhibited strong spatial dependence for the 0-30 cm and weak spatial dependence at 30-60 and 60-90 cm depths. Sand and silt had a non-spatial dependence at 0-30 cm and weak spatial dependency at 30-60 and 60-90 cm depths. The spatial variability in small distances of ECe, CEC, pH and ESP generally increased with depth. All geostatistical range values were greater than 1168 m. The results reported herein indicated that the strong spatial dependency of soil properties would lead to the extrinsic factors such as ground water level and drainage. It is important to know the spatial dependence of soil parameters, as management parameters with strong spatial dependence will be more readily managed and an accurate site-specific scheme for precision farming more easily developed.

  16. Drivers for spatial variability in agricultural soil organic carbon stocks in Germany

    Science.gov (United States)

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

    2017-04-01

    Soil organic carbon is one of the largest components of the global carbon cycle. It has recently gained importance in global efforts to mitigate climate change through carbon sequestration. In order to find locations suitable for carbon sequestration, and estimate the sequestration potential, however, it is necessary to understand the factors influencing the high spatial variability of soil organic carbon stocks. Due to numerous interacting factors that influence its dynamics, soil organic carbon stocks are difficult to predict. In the course of the German Agricultural Soil Inventory over 2500 agricultural sites were sampled and their soil organic carbon stocks determined. Data relating to more than 200 potential drivers of SOC stocks were compiled from laboratory measurements, farmer questionnaires and climate stations. The aims of this study were to 1) give an overview of soil organic carbon stocks in Germany's agricultural soils, 2) to quantify and explain the influence of explanatory variables on soil organic carbon stocks. Two different machine learning algorithms were used to identify the most important variables and multiple regression models were used to explore the influence of those variables. Models for predicting carbon stocks in different depth increments between 0-100 cm were developed, explaining up to 62% (validation, 98% calibration) of total variance. Land-use, land-use history, clay content and electrical conductivity were main predictors in the topsoil, while bedrock material, relief and electrical conductivity governed the variability of subsoil carbon stocks. We found 32% of all soils to be deeply anthropogenically transformed. The influence of climate related variables was surprisingly small (≤5% of explained variance), while site variables explained a large share of soil carbon variability (46-100% of explained variance), in particular in the subsoil. Thus, the understanding of SOC dynamics at regional scale requires a thorough description

  17. Spatiotemporal Variability of Hillslope Soil Moisture Across Steep, Highly Dissected Topography

    Science.gov (United States)

    Jarecke, K. M.; Wondzell, S. M.; Bladon, K. D.

    2016-12-01

    Hillslope ecohydrological processes, including subsurface water flow and plant water uptake, are strongly influenced by soil moisture. However, the factors controlling spatial and temporal variability of soil moisture in steep, mountainous terrain are poorly understood. We asked: How do topography and soils interact to control the spatial and temporal variability of soil moisture in steep, Douglas-fir dominated hillslopes in the western Cascades? We will present a preliminary analysis of bimonthly soil moisture variability from July-November 2016 at 0-30 and 0-60 cm depth across spatially extensive convergent and divergent topographic positions in Watershed 1 of the H.J. Andrews Experimental Forest in central Oregon. Soil moisture monitoring locations were selected following a 5 m LIDAR analysis of topographic position, aspect, and slope. Topographic position index (TPI) was calculated as the difference in elevation to the mean elevation within a 30 m radius. Convergent (negative TPI values) and divergent (positive TPI values) monitoring locations were established along northwest to northeast-facing aspects and within 25-55 degree slopes. We hypothesized that topographic position (convergent vs. divergent), as well as soil physical properties (e.g., texture, bulk density), control variation in hillslope soil moisture at the sub-watershed scale. In addition, we expected the relative importance of hillslope topography to the spatial variability in soil moisture to differ seasonally. By comparing the spatiotemporal variability of hillslope soil moisture across topographic positions, our research provides a foundation for additional understanding of subsurface flow processes and plant-available soil-water in forests with steep, highly dissected terrain.

  18. [Spatial pattern of soil fertility in Bashan tea garden: a prediction based on environmental auxiliary variables].

    Science.gov (United States)

    Qin, Le-feng; Yang, Chao; Lin, Fen-fang; Yang, Ning; Zheng, Xin-yu; Xu, Hong-wei; Wang, Ke

    2010-12-01

    Taking topographic factors and NDVI as auxiliary variables, and by using regression-kriging method, the spatial variation pattern of soil fertility in Bashan tea garden in the hilly area of Fuyang City was explored. The spatial variability of the soil fertility was mainly attributed to the structural factors such as relative elevation and flat/vertical curvature. The lower the relative elevation, the worse the soil fertility was. The overall soil fertility level was relatively high, and the area with lower soil fertility only accounted for 5% of the total. By using regression-kriging method with relative elevation as auxiliary variable, the prediction accuracy of soil fertility was obviously higher than that by using ordinary kriging method, with the mean error and root mean square error being 0. 028 and 0. 108, respectively. It was suggested that the prediction method used in this paper could fully reflect the effects of environmental variables on soil fertility , improve the prediction accuracy about the spatial pattern of soil fertility, and provide scientific basis for the precise management of tea garden.

  19. Amplification and dampening of soil respiration by changes in temperature variability

    Science.gov (United States)

    C.A. Sierra; M.E. Harmon; E.A. Thomann; S.S. Perakis; H.W. Loescher

    2011-01-01

    Accelerated release of carbon from soils is one of the most important feedbacks related to anthropogenically induced climate change. Studies addressing the mechanisms for soil carbon release through organic matter decomposition have focused on the effect of changes in the average temperature, with little attention to changes in temperature variability. Anthropogenic...

  20. Spatial variability of arsenic in relation with some soil forming factors ...

    African Journals Online (AJOL)

    Soil and water samples collected from Bijar area were analyzed in order to investigate arsenic contamination sources and their human risk potentiality assessment. Routine physical and chemical characteristics, iron oxides and arsenic contents were measured in 227 soil samples. Spatial variability of arsenic was ...

  1. Soil Moisture Controls for Spatial Variability for a Humid Forest Hillslope

    Science.gov (United States)

    Kim, S.; Gwak, Y.

    2016-12-01

    Soil moisture is an important variable in explaining hydrological processes at hillslope scale. The distribution of soil moisture along a hillslope is related to the spatial distribution of the soil properties, the topography, the soil depth, and the vegetation. In order to investigate the factors affecting soil moisture, various environmental data were collected from a humid forest hillslope in this study. Several factors (the wetness index; the contributing area; the local slope; the soil depth; the composition of sand, silt, and clay; the scaling parameter; the hydraulic conductivity; the tree diameter at breast height; and the total weighted basal area) were evaluated for their effect on soil moisture and its distribution over the hillslope at depths of 10, 30, and 60 cm. The relationships of the various factors with the spatial variability of soil moisture indicated the existence of a threshold soil moisture which is related to the composition of the soil and the factors related to the distribution of water in the study area.

  2. Variability in chemistry of surface and soil waters of an ...

    African Journals Online (AJOL)

    Water chemistry is important for the maintenance of wetland structure and function. Interpreting ecological patterns in a wetland system therefore requires an in-depth understanding of the water chemistry of that system. We investigated the spatial distribution of chemical solutes both in soil pore water and surface water, ...

  3. Incorporation of water vapor transfer in the JULES Land Surface Model: implications for key soil variables and land surface fluxes

    OpenAIRE

    Garcia Gonzalez, R.; Verhoef, A.; Luigi Vidale, P.; I. Braud

    2012-01-01

    This study focuses on the mechanisms underlying water and heat transfer in upper soil layers, and their effects on soil physical prognostic variables and the individual components of the energy balance. The skill of the JULES (Joint UK Environment Simulator) land surface model (LSM) to simulate key soil variables, such as soil moisture content and surface temperature, and fluxes such as evaporation, is investigated. The Richards equation for soil water transfer, as used in most LSMs, was upda...

  4. Measurements of the fallout flux of beryllium-7 and its variability in the soil

    OpenAIRE

    Andrello, Avacir Casanova; Appoloni, Carlos Roberto

    2010-01-01

    The aim of this study was to examine the beryllium-7 behavior in the soil. Natural variability of beryllium-7 concentration was calculated to be about 23% (relative standard deviation), and the depth distribution could be approximated by an exponential decay in bare soil, with an average penetration depth in the soil about 1 cm. The nuclide was not found below 2 cm depth, which confirmed its utilization to infer the erosion processes as a tracer of soil surface. The maximum beryllium-7 concen...

  5. Field Scale Studies on the Spatial Variability of Soil Quality Indicators in Washington State, USA

    Directory of Open Access Journals (Sweden)

    Jeffrey L. Smith

    2011-01-01

    Full Text Available Arable lands are needed for sustainable agricultural systems to support an ever-growing human population. Soil quality needs to be defined to assure that new land brought into crop production is sustainable. To evaluate soil quality, a number of soil attributes will need to be measured, evaluated, and integrated into a soil-quality index using the multivariable indicator kriging (MVIK procedure. This study was conducted to determine the spatial variability and correlation of indicator parameters on a field scale with respect to soil quality and suitability for use with MVIK. The variability of the biological parameters decreased in the order of respiration > enzyme assays and qCO2 > microbial biomass C. The distribution frequency of all parameters except respiration were normal although the spatial distribution across the landscape was highly variable. The biological parameters showed little correlation with each other when all data points were considered; however, when grouped in smaller sections, the correlations were more consistent with observed patterns across the field. To accurately assess soil quality, and arable land use, consideration of spatial and temporal variability, soil conditions, and other controlling factors must be taken into account.

  6. Spatial variability of soil potassium in sugarcane areas subjected to the application of vinasse.

    Science.gov (United States)

    De Carvalho, Laércio A; Meurer, Ismael; Da Silva Junior, Carlos A; Santos, Cristiane F B; Libardi, Paulo L

    2014-12-01

    When deposited on land the vinasse can promote improvement in fertility, however, often fertilizer application occurs in areas considered homogeneous, without taking into account the variability of the soil. The objective of this study was to evaluate the effect of vinasse application on potassium content in two classes of soils cultivated with sugarcane, and characterize the spatial variability of soil using geostatistical techniques. In the 2010 and 2011 crop year, soil samples were collected from an experimental grid at 0-0.2 and 0.2-0.4 m depth in three soils cultivated with sugarcane, totaling 90 samplings in each grid, for the determination of pH, calcium (Ca), magnesium (Mg), potassium (K), phosphorus (P), aluminum (Al) and potential acidity (H + Al). The data have been submitted to analysis of descriptive statistics and the K attribute was subjected to geostatistical analysis. The coefficient of variation indicated medium and high variability of K for the three soils. The results showed that the spatial dependence of K increased in depth to FRce and decreased to PHlv, indicating that the attribute could have followed the pattern of distribution of clay in depth. The investigation of the spatial variability of K on the surface and subsurface soils provided the definition of management zones with different levels of fertility, which can be organized into sub-areas for a more efficient management of the resources and the environment.

  7. Spatial variability of soil potassium in sugarcane areas subjected to the application of vinasse

    Directory of Open Access Journals (Sweden)

    LAÉRCIO A. DE CARVALHO

    2014-12-01

    Full Text Available When deposited on land the vinasse can promote improvement in fertility, however, often fertilizer application occurs in areas considered homogeneous, without taking into account the variability of the soil. The objective of this study was to evaluate the effect of vinasse application on potassium content in two classes of soils cultivated with sugarcane, and characterize the spatial variability of soil using geostatistical techniques. In the 2010 and 2011 crop year, soil samples were collected from an experimental grid at 0-0.2 and 0.2-0.4 m depth in three soils cultivated with sugarcane, totaling 90 samplings in each grid, for the determination of pH, calcium (Ca, magnesium (Mg, potassium (K, phosphorus (P, aluminum (Al and potential acidity (H + Al. The data have been submitted to analysis of descriptive statistics and the K attribute was subjected to geostatistical analysis. The coefficient of variation indicated medium and high variability of K for the three soils. The results showed that the spatial dependence of K increased in depth to FRce and decreased to PHlv, indicating that the attribute could have followed the pattern of distribution of clay in depth. The investigation of the spatial variability of K on the surface and subsurface soils provided the definition of management zones with different levels of fertility, which can be organized into sub-areas for a more efficient management of the resources and the environment.

  8. Land agroecological quality assessment in conditions of high spatial soil cover variability at the Pereslavskoye Opolye.

    Science.gov (United States)

    Morev, Dmitriy; Vasenev, Ivan

    2015-04-01

    The essential spatial variability is mutual feature for most natural and man-changed soils at the Central region of European territory of Russia. The original spatial heterogeneity of forest soils has been further complicated by a specific land-use history and human impacts. For demand-driven land-use planning and decision making the quantitative analysis and agroecological interpretation of representative soil cover spatial variability is an important and challenging task that receives increasing attention from private companies, governmental and environmental bodies. Pereslavskoye Opolye is traditionally actively used in agriculture due to dominated high-quality cultivated soddy-podzoluvisols which are relatively reached in organic matter (especially for conditions of the North part at the European territory of Russia). However, the soil cover patterns are often very complicated even within the field that significantly influences on crop yield variability and have to be considered in farming system development and land agroecological quality evaluation. The detailed investigations of soil regimes and mapping of the winter rye yield have been carried in conditions of two representative fields with slopes sharply contrasted both in aspects and degrees. Rye biological productivity and weed infestation have been measured in elementary plots of 0.25 m2 with the following analysis the quality of the yield. In the same plot soil temperature and moisture have been measured by portable devices. Soil sampling was provided from three upper layers by drilling. The results of ray yield detailed mapping shown high differences both in average values and within-field variability on different slopes. In case of low-gradient slope (field 1) there is variability of ray yield from 39.4 to 44.8 dt/ha. In case of expressed slope (field 2) the same species of winter rye grown with the same technology has essentially lower yield and within-field variability from 20 to 29.6 dt/ha. The

  9. Exploring the spatial variability of soil properties in an Alfisol Catena

    Energy Technology Data Exchange (ETDEWEB)

    Rosemary, F.; Vitharana, U. W. A.; Indraratne, S. P.; Weerasooriya, R.; Mishra, U.

    2016-11-10

    Detailed digital soil maps showing the spatial heterogeneity of soil properties consistent with the landscape are required for site-specific management of plant nutrients, land use planning and process-based environmental modeling. We characterized the short-scale spatial heterogeneity of soil properties in an Alfisol catena in a tropical landscape of Sri Lanka. The impact of different land-uses (paddy, vegetable and un-cultivated) was examined to assess the impact of anthropogenic activities on the variability of soil properties at the catenary level. Conditioned Latin hypercube sampling was used to collect 58 geo-referenced topsoil samples (0–30 cm) from the study area. Soil samples were analyzed for pH, electrical conductivity (EC), organic carbon (OC), cation exchange capacity (CEC) and texture. The spatial correlation between soil properties was analyzed by computing crossvariograms and subsequent fitting of theoretical model. Spatial distribution maps were developed using ordinary kriging. The range of soil properties, pH: 4.3–7.9; EC: 0.01–0.18 dS m–1 ; OC: 0.1–1.37%; CEC: 0.44– 11.51 cmol (+) kg–1 ; clay: 1.5–25% and sand: 59.1–84.4% and their coefficient of variations indicated a large variability in the study area. Electrical conductivity and pH showed a strong spatial correlation which was reflected by the cross-variogram close to the hull of the perfect correlation. Moreover, cross-variograms calculated for EC and Clay, CEC and OC, CEC and clay and CEC and pH indicated weak positive spatial correlation between these properties. Relative nugget effect (RNE) calculated from variograms showed strongly structured spatial variability for pH, EC and sand content (RNE < 25%) while CEC, organic carbon and clay content showed moderately structured spatial variability (25% < RNE < 75%). Spatial dependencies for examined soil properties ranged from 48 to 984 m. The mixed effects model fitting followed by Tukey's post

  10. Can we quantify the variability of soil moisture across scales using Electromagnetic Induction ?

    Science.gov (United States)

    Robinet, Jérémy; von Hebel, Christian; van der Kruk, Jan; Govers, Gerard; Vanderborght, Jan

    2017-04-01

    Soil moisture is a key variable in many natural processes. Therefore, technological and methodological advancements are of primary importance to provide accurate measurements of spatial and temporal variability of soil moisture. In that context, ElectroMagnetic Induction (EMI) instruments are often cited as a hydrogeophysical method with a large potential, through the measurement of the soil apparent electrical conductivity (ECa). To our knowledge, no studies have evaluated the potential of EMI to characterize variability of soil moisture on both agricultural and forested land covers in a (sub-) tropical environment. These differences in land use could be critical as differences in temperature, transpiration and root water uptake can have significant effect, notably on the electrical conductivity of the pore water. In this study, we used an EMI instrument to carry out a first assessment of the impact of deforestation and agriculture on soil moisture in a subtropical region in the south of Brazil. We selected slopes of different topographies (gentle vs. steep) and contrasting land uses (natural forest vs. agriculture) within two nearby catchments. At selected locations on the slopes, we measured simultaneously ECa using EMI and a depth-weighted average of the soil moisture using TDR probes installed within soil pits. We found that the temporal variability of the soil moisture could not be measured accurately with EMI, probably because of important temporal variations of the pore water electrical conductivity and the relatively small temporal variations in soil moisture content. However, we found that its spatial variability could be effectively quantified using a non-linear relationship, for both intra- and inter-slopes variations. Within slopes, the ECa could explained between 67 and 90% of the variability of the soil moisture, while a single non-linear model for all the slopes could explain 55% of the soil moisture variability. We eventually showed that combining

  11. Soil Physical and Environmental Conditions Controlling Patterned-Ground Variability at a Continuous Permafrost Site, Svalbard

    DEFF Research Database (Denmark)

    Watanabe, Tatsuya; Matsuoka, Norikazu; Christiansen, Hanne Hvidtfeldt

    2017-01-01

    This study examines soil physical and environmental conditions controlling patterned-ground variability on an alluvial fan in a continuous permafrost landscape, at Adventdalen, Svalbard. On-site monitoring of ground temperature, soil moisture and snow depth, laboratory analyses of soil physical...... properties and principal component analysis indicate that the distribution of patterned ground depends primarily on soil texture, soil moisture and the winter ground thermal regime associated with snow cover. Mudboils and composite patterns (mudboils surrounded by small polygons) occupy well-drained areas...... composed of clay-rich aeolian sediments. Compared to mudboils, composite patterns show a sharper contrast in soil texture between barren centres and vegetated rims. Hummocks filled with organic materials develop on poorly drained lowlands associated with a shallow water table. Ice-wedge polygons...

  12. Assessing scales of spatial & temporal variability in radiocarbon contents of soil organic carbon

    Science.gov (United States)

    van der Voort, Tessa Sophia; Feng, Xiaojuan; Hagedorn, Frank; Eglinton, Timothy

    2014-05-01

    Soil organic matter (SOM) forms the largest terrestrial reservoir of carbon outside of sedimentary rocks and it provides the fundamental reservoir for nutrients that sustains vegetation and the microbial communities. With ongoing changes in land-use and climate, SOM is also subject to change, with potentially major consequences for soil as a resource and for global biogeochemical cycles. Radiocarbon is a powerful tool for assessing SOM dynamics and is increasingly used in studies of carbon turnover. However, due to the nature of the measurement, comprehensive 14C studies of soils systems are rare. In particular, information on spatial variability in the radiocarbon contents of soils is limited. The present study aims to develop and apply a comprehensive four-dimensional approach to explore heterogeneity in bulk SOM 14C, with a broader goal of assessing controls on organic matter stability and vulnerability in soils across Switzerland. Focusing on range of Swiss soil types, we examine lateral variability in 14C over plot (decimeter to meter) to regional scales, vertical variability from surface to deeper soil horizons, and temporal variability by comparing present-day with archived (legacy) samples. Preliminary results show that there are large differences in SOM 14C age across small lateral and vertical distances within soil systems. Ultimately, studies of bulk variability will be followed up with analyses of SOM sub-fractions, including 14C measurements at the molecular level. Investigating 14C variability over various space and time domains may shed light on the scales of processes that dictate the composition and vulnerability of SOM, and provide valuable constraints on models of SOM turnover.

  13. Temporal and spatial variability of soil hydraulic properties with implications on soil moisture simulations and irrigation scheduling

    Science.gov (United States)

    Feki, Mouna; Ravazzani, Giovanni; Mancini, Marco

    2017-04-01

    The increase in consumption of water resources, combined with climate change impacts, calls for new sources of water supply and/or different managements of available resources in agriculture. One way to increase the quality and quantity of agricultural production is using modern technology to make farms more "intelligent", the so-called "precision agriculture" also known as 'smart farming'. To this aim hydrological models play crucial role for their ability to simulate water movement from soil surface to groundwater and to predict onset of stress condition. However, optimal use of mathematical models requires intensive, time consuming and expensive collection of soil related parameters. Typically, soils to be characterized, exhibit large variations in space and time as well during the cropping cycle, due to biological processes and agricultural management practices: tillage, irrigation, fertilization and harvest. Soil properties are subjected to diverse physical and chemical changes that lead to a non-stability in terms of water and chemical movements within the soil and to the groundwater as well. The aim of this study is to assess the variability of soil hydraulic properties over a cropping cycle. The study site is a surface irrigated Maize field located in Secugnago (45◦13'31.70" N, 9 ◦36'26.82 E), in Northern Italy-Lombardy region. The field belongs to the Consortium Muzza Bassa Lodigiana, within which meteorological data together with soil moisture were monitored during the cropping season of 2015. To investigate soil properties variations, both measurements in the field and laboratory tests on both undisturbed and disturbed collected samples were performed. Soil samples were taken from different locations within the study area and at different depths (surface, 20cm and 40cm) at the beginning and in the middle of the cropping cycle and after the harvest. During three measuring campaigns, for each soil samples several parameters were monitored (Organic

  14. Field potential soil variability index to identify precision agriculture opportunity

    Science.gov (United States)

    Precision agriculture (PA) technologies used for identifying and managing within-field variability are not widely used despite decades of advancement. Technological innovations in agronomic tools, such as canopy reflectance or electrical conductivity sensors, have created opportunities to achieve a ...

  15. Spatial Variability of Dielectric Properties in Field Soils

    National Research Council Canada - National Science Library

    Hendrickx, J

    2001-01-01

    ... since it directly influences the three other properties The variability of these properties may be such that either potential land mine signatures are overshadowed or false alarms result In this paper...

  16. Determinants of spatial variability of methane emissions from wet grasslands on peat soil

    NARCIS (Netherlands)

    Pol-Van Dasselaar, van den A.; Beusichem, van M.L.; Oenema, O.

    1999-01-01

    Methane (CH4) emissions from soils, representing the consequence of CH4 production, CH4 consumption and CH4 transport, are poorly characterised and show a large spatial variability. This study aimed to assess the determinants of field-scale spatial variability of CH4 emissions from wet grasslands on

  17. Quantifying soil and critical zone variability in a forested catchment through digital soil mapping

    Science.gov (United States)

    Quantifying catchment scale soil property variation yields insights into critical zone evolution and function. The objective of this study was to quantify and predict the spatial distribution of soil properties within a high elevation forested catchment in southern AZ, USA using a combined set of di...

  18. Influence of tillage in soil penetration resistance variability in an olive orchard

    Science.gov (United States)

    López de Herrera, Juan; Herrero Tejedor, Tomas; Saa-Requejo, Antonio; Tarquis, Ana M.

    2015-04-01

    Soil attributes usually present a high degree of spatial variation due to a combination of physical, chemical, biological or climatic processes operating at different scales. The quantification and interpretation of such variability is a key issue for site-specific soil management (Brouder et al., 2001). The usual geostatistical approach studies soil variability by means of the semi-variograms. However, recently a multiscaling approach has been applied on the determination of the scaling data properties (Kravechenko et al., 1999; Caniego et al., 2005; Tarquis et al., 2008). This work focus in the multifractal analysis as a way to characterize the variability of field data in a case study of soil penetrometer resistance (SPR) in two olive orchards, one applying tillage for 20 years and the other one non. The field measurements and soil data were obtained at the village of Puebla de Almenara (Cuenca, Spain) (39o 47'42.37'N, 2o 49'29.23'W) with 869 m of elevation approximately. The characteristic of the soil at the surface is classified as clay loam texture according to Guidelines for soil description of FAO. The soil consists of clays and red silts with some clusters of limestone's and sands. Two transect data were collected from 128 points between the squared of the olive tree, tillage and no tillage area, for SPR readings with a sampling interval of 50 cm. In each sampling, readings were obtained from 0 cm till 20 cm of depth, with an interval of 5 cm. The multifractal spectrum for each area and depth was estimated showing a characteristic pattern and differentiating both treatments. References Brouder, S., Hofmann, B., Reetz, H.F., 2001. Evaluating spatial variability of soil parameters for input management. Better Crops 85, 8-11. Kravchenko, A.N., Boast, C.W., Bullock, D.G., 1999. Multifractal analysis of soil spatial variability. Agron. J. 91, 1033-1041. Caniego, F.J., R. Espejo, M.A. Martín, F. San José, 2005. Multifractal scaling of soil spatial variability

  19. Investigation of the reduction in uncertainty due to soil variability when conditioning a random field using Kriging

    NARCIS (Netherlands)

    Lloret Cabot, M.; Hicks, M.A.; Van den Eijnden, A.P.

    2012-01-01

    Spatial variability of soil properties is inherent in soil deposits, whether as a result of natural geological processes or engineering construction. It is therefore important to account for soil variability in geotechnical design in order to represent more realistically a soil’s in situ state. This

  20. Assessment of spatial variability of soil thermal properties in cultivated field

    Science.gov (United States)

    Usowicz, Boguslaw; Lipiec, Jerzy

    2017-04-01

    Most of soil physical properties are spatially variable both in regional and field scale. Spatial heterogeneity of soil properties in the field is related to the nature of the soil itself, but some of the variation is caused by tillage and other management practices. The aim of this work was to determine spatial variability of thermal properties on the cultivated field (40 x 350 m) using geostatistical method. The present work used data obtained from the measurements of topsoil soil texture (sand, silt and clay content), organic carbon, water content, bulk density, particle density, thermal conductivity, heat capacity and thermal diffusivity after harvest of triticale. The measurements were done in 45 points using TDR and KD2Pro for soil water content and thermal properties, respectively. Moreover, measurements of the thermal properties were performed in the laboratory at dry and saturated soil. The coefficient of variations (CV) varied from 1.6% for the particle density to 67% for the clay content. Among the thermal properties the most variable was thermal diffusivity at saturation (24%) and the least variable thermal conductivity in dry state (8.4%). The exponential semivariogram models matched well with empirical semivariogram. The range of the thermal properties measured in the field varied from 10 m for the thermal diffusivity to 23 m for the thermal conductivity. The ranges in dry and saturated soil were greater than at field water content. Among the remaining properties the largest range of the semivariograms was for soil textural fractions (100-250 m) and bulk density (145 m) and the lowest water content (14 m). This indicates that the thermal properties were resultant of both soil water content and bulk density. Most of the soil properties exhibited strong and moderate spatial dependency. Heterogeneity and variation of soil physical and thermal parameters in a field due to soil cultivation should be taken into consideration for a successful agricultural

  1. Spatial variability of vegetation index and soil properties in an integrated crop-livestock system

    Directory of Open Access Journals (Sweden)

    Alberto C. de C. Bernardi

    Full Text Available ABSTRACT The knowledge of soil property spatial variability is useful for determining the rational use of inputs, such as the site-specific application of lime and fertilizer. The objective of this study was to evaluate the vegetation index and spatial variability of physical and chemical soil properties in an integrated crop-livestock system (ICLS. Soil samples were taken from a 6.9 ha area in a regular hexagon grid at 0-0.20 m depths. Soil P, K, Ca, Mg, and cation exchange capacity - CEC; base saturation; clay and sand were analyzed. Soil electrical conductivity (ECa was measured with a contact sensor. The site was evaluated at the end of the corn season (April and during forage production (October using Landsat 5 images, remote sensing techniques and a geographic information system (GIS. Results showed that the normalized difference vegetation index (NDVI was associated with ECa and soil parameters, indicating crop and pasture variations in the ICLS. Geostatistics and GIS were effective tools for collecting data regarding the spatial variability of soil and crop indicators, identifying variation trends in the data, and assisting data interpretation to determine adequate management strategies.

  2. High temporal and spatial variability of atmospheric-methane oxidation in Alpine glacier-forefield soils.

    Science.gov (United States)

    Chiri, Eleonora; Nauer, Philipp A; Rainer, Edda-Marie; Zeyer, Josef; Schroth, Martin H

    2017-07-07

    Glacier-forefield soils can provide a substantial sink for atmospheric CH4, facilitated by aerobic methane-oxidizing bacteria (MOB). However, MOB activity, abundance, and community structure may be affected by soil age, location in different forefield landforms, and temporal fluctuations in soil-physical parameters. We assessed spatial and temporal variability of atmospheric CH4 oxidation in an Alpine glacier forefield during the snow-free season 2013. We quantified CH4 flux in soils of increasing age and in different landforms (sandhill, terrace, floodplain) using soil-gas-profile and static flux-chamber methods. To determine MOB abundance and community structure, we employed pmoA-gene-based quantitative PCR and targeted-amplicon sequencing. Uptake of CH4 increased in magnitude and decreased in variability with increasing soil age. Sandhill soils exhibited CH4 uptake ranging from -0.03- -3.7 mg CH4 m-2 d-1 Floodplain and terrace soils exhibited smaller uptake and even intermittent CH4 emissions. Linear mixed-effect models indicated that soil age and landform were dominating factors shaping CH4 flux, followed by cumulative rainfall (weighted sum ≤ 4 d prior to sampling). Of 31 MOB operational taxonomic units retrieved, ∼30% were potentially novel, and ∼50% were affiliated with Upland Soil Clusters gamma and alpha. The MOB community structures in floodplain and terrace soils were nearly identical, but differed significantly from highly variable sandhill-soil communities. We conclude that soil age and landform modulate the soil CH4 sink strength in glacier forefields, and recent rainfall affects its short-term variability. This should be taken into account when including this environment in future CH4 inventories.Importance Oxidation of methane (CH4) in well-drained, "upland" soils is an important mechanism for the removal of this potent greenhouse gas from the atmosphere. It is largely mediated by aerobic, methane-oxidizing bacteria (MOB). Whereas there is

  3. A study of soil moisture variability for landmine detection by the neutron technique

    Directory of Open Access Journals (Sweden)

    Avdić Senada

    2007-01-01

    Full Text Available This paper is focused on the space and temporal variability of soil moisture experimental data acquired at a few locations near landmine fields in the Tuzla Canton, as well as on the quantification of the statistical nature of soil moisture data on a small spatial scale. Measurements of soil water content at the surface were performed by an electro-magnetic sensor over 1 25, and 100 m2 grids, at intervals of 0.2, 0.5, and 1 m, respectively. The sampling of soil moisture at different spatial resolutions and over different grid sizes has been investigated in order to achieve the quantification of the statistical nature of soil moisture distribution. The statistical characterization of spatial variability was performed through variogram and correlogram analysis of measurement results. The temporal variability of the said samples was examined over a two-season period. For both sampling periods, the spatial correlation length is about 1 to 2 m, respectively, or less. Thus, sampling should be done on a larger spatial scale, in order to capture the variability of the investigated areas. Since the characteristics of many landmine sensors depend on soil moisture, the results of this study could form a useful data base for multisensor landmine detection systems with a promising performance.

  4. Spatial variability of δ18O-PO4 in soils.

    Science.gov (United States)

    Granger, Steve; Blackwell, Martin; Tamburini, Federica; Guo, Rongrong; Peukert, Sabine; McGrath, Steve

    2014-05-01

    There is growing interest in the potential for using the δ18OPO4 values of different phosphate sources in the environment to enable identification of sources of phosphate in surface waters. The basis of the study is the belief that different sources of PO4 may have different δ18O values. One of the primary sources of PO4 in runoff from agricultural land is the soil itself. Therefore, in order to account for the PO4 derived from soils in surface waters, it is vital that the degree of spatial variability of its δ18O isotopic values are known, in order that suitable soil sampling approaches can be taken when assessing the soil as a source in future studies. A spatial study of the variability of the δ18OPO4 variability of soils collected from a grazed pasture on the North Wyke Farm Platform was carried out incorporating grid-sampling at a range of spatial scales. Results show that variability across a range of scales is minimal, meaning that, in this case, a relatively small number of samples would be required in order to identify accurately the mean δ18OPO4 value of the soil. This study represents an important contribution towards the methodological development studies required in this field of research in order that the full potential of the δ18OPO4 technique for biological and environmental research can be achieved.

  5. Predicting active-layer soil thickness using topographic variables at a small watershed scale.

    Science.gov (United States)

    Li, Aidi; Tan, Xing; Wu, Wei; Liu, Hongbin; Zhu, Jie

    2017-01-01

    Knowledge about the spatial distribution of active-layer (AL) soil thickness is indispensable for ecological modeling, precision agriculture, and land resource management. However, it is difficult to obtain the details on AL soil thickness by using conventional soil survey method. In this research, the objective is to investigate the possibility and accuracy of mapping the spatial distribution of AL soil thickness through random forest (RF) model by using terrain variables at a small watershed scale. A total of 1113 soil samples collected from the slope fields were randomly divided into calibration (770 soil samples) and validation (343 soil samples) sets. Seven terrain variables including elevation, aspect, relative slope position, valley depth, flow path length, slope height, and topographic wetness index were derived from a digital elevation map (30 m). The RF model was compared with multiple linear regression (MLR), geographically weighted regression (GWR) and support vector machines (SVM) approaches based on the validation set. Model performance was evaluated by precision criteria of mean error (ME), mean absolute error (MAE), root mean square error (RMSE), and coefficient of determination (R2). Comparative results showed that RF outperformed MLR, GWR and SVM models. The RF gave better values of ME (0.39 cm), MAE (7.09 cm), and RMSE (10.85 cm) and higher R2 (62%). The sensitivity analysis demonstrated that the DEM had less uncertainty than the AL soil thickness. The outcome of the RF model indicated that elevation, flow path length and valley depth were the most important factors affecting the AL soil thickness variability across the watershed. These results demonstrated the RF model is a promising method for predicting spatial distribution of AL soil thickness using terrain parameters.

  6. Predicting active-layer soil thickness using topographic variables at a small watershed scale.

    Directory of Open Access Journals (Sweden)

    Aidi Li

    Full Text Available Knowledge about the spatial distribution of active-layer (AL soil thickness is indispensable for ecological modeling, precision agriculture, and land resource management. However, it is difficult to obtain the details on AL soil thickness by using conventional soil survey method. In this research, the objective is to investigate the possibility and accuracy of mapping the spatial distribution of AL soil thickness through random forest (RF model by using terrain variables at a small watershed scale. A total of 1113 soil samples collected from the slope fields were randomly divided into calibration (770 soil samples and validation (343 soil samples sets. Seven terrain variables including elevation, aspect, relative slope position, valley depth, flow path length, slope height, and topographic wetness index were derived from a digital elevation map (30 m. The RF model was compared with multiple linear regression (MLR, geographically weighted regression (GWR and support vector machines (SVM approaches based on the validation set. Model performance was evaluated by precision criteria of mean error (ME, mean absolute error (MAE, root mean square error (RMSE, and coefficient of determination (R2. Comparative results showed that RF outperformed MLR, GWR and SVM models. The RF gave better values of ME (0.39 cm, MAE (7.09 cm, and RMSE (10.85 cm and higher R2 (62%. The sensitivity analysis demonstrated that the DEM had less uncertainty than the AL soil thickness. The outcome of the RF model indicated that elevation, flow path length and valley depth were the most important factors affecting the AL soil thickness variability across the watershed. These results demonstrated the RF model is a promising method for predicting spatial distribution of AL soil thickness using terrain parameters.

  7. Plant trait diversity buffers variability in denitrification potential over changes in season and soil conditions.

    Directory of Open Access Journals (Sweden)

    Bonnie M McGill

    Full Text Available BACKGROUND: Denitrification is an important ecosystem service that removes nitrogen (N from N-polluted watersheds, buffering soil, stream, and river water quality from excess N by returning N to the atmosphere before it reaches lakes or oceans and leads to eutrophication. The denitrification enzyme activity (DEA assay is widely used for measuring denitrification potential. Because DEA is a function of enzyme levels in soils, most ecologists studying denitrification have assumed that DEA is less sensitive to ambient levels of nitrate (NO(3(- and soil carbon and thus, less variable over time than field measurements. In addition, plant diversity has been shown to have strong effects on microbial communities and belowground processes and could potentially alter the functional capacity of denitrifiers. Here, we examined three questions: (1 Does DEA vary through the growing season? (2 If so, can we predict DEA variability with environmental variables? (3 Does plant functional diversity affect DEA variability? METHODOLOGY/PRINCIPAL FINDINGS: The study site is a restored wetland in North Carolina, US with native wetland herbs planted in monocultures or mixes of four or eight species. We found that denitrification potentials for soils collected in July 2006 were significantly greater than for soils collected in May and late August 2006 (p<0.0001. Similarly, microbial biomass standardized DEA rates were significantly greater in July than May and August (p<0.0001. Of the soil variables measured--soil moisture, organic matter, total inorganic nitrogen, and microbial biomass--none consistently explained the pattern observed in DEA through time. There was no significant relationship between DEA and plant species richness or functional diversity. However, the seasonal variance in microbial biomass standardized DEA rates was significantly inversely related to plant species functional diversity (p<0.01. CONCLUSIONS/SIGNIFICANCE: These findings suggest that

  8. Efficacy of a Phosphate-Charged Soil Material in Supplying Phosphate for Plant Growth in Soilless Root Media

    Directory of Open Access Journals (Sweden)

    Young-Mi Oh

    2016-01-01

    Full Text Available A soil material high in crystalline Fe hydrous oxides and noncrystalline Al hydrous oxides collected from the Bw horizon of a Hemcross soil containing allophane from the state of Oregon was charged with phosphate-P at rates of 0, 2.2, and 6.5 mg·g−1, added to a soilless root medium at 5% and 10% by volume, and evaluated for its potential to supply phosphate at a low, stable concentration during 14 weeks of tomato (Solanum esculentum L. seedling growth. Incorporation of the soil material improved pH stability, whether it was charged with phosphate or not. Bulk solution phosphate-P concentrations in the range of 0.13 to 0.34 mg·dm−3 were associated with P deficiency. The only treatment that sustained an adequate bulk solution concentration of phosphate-P above 0.34 mg·dm−3 for the 14 weeks of testing contained 10% soil material charged with 6.5 mg·g−1 P, but initial dissolved P concentrations were too high (>5 mg·g−1 phosphate-P from the standpoint of phosphate leaching. The treatment amended with 10% soil material charged with 2.2 mg·g−1 P maintained phosphate-P within an acceptable range of 0.4 to 2.3 mg·dm−3 for 48 d in a medium receiving no postplant phosphate fertilization.

  9. McMaster Mesonet soil moisture dataset: description and spatio-temporal variability analysis

    Directory of Open Access Journals (Sweden)

    K. C. Kornelsen

    2013-04-01

    Full Text Available This paper introduces and describes the hourly, high-resolution soil moisture dataset continuously recorded by the McMaster Mesonet located in the Hamilton-Halton Watershed in Southern Ontario, Canada. The McMaster Mesonet consists of a network of time domain reflectometer (TDR probes collecting hourly soil moisture data at six depths between 10 cm and 100 cm at nine locations per site, spread across four sites in the 1250 km2 watershed. The sites for the soil moisture arrays are designed to further improve understanding of soil moisture dynamics in a seasonal climate and to capture soil moisture transitions in areas that have different topography, soil and land cover. The McMaster Mesonet soil moisture constitutes a unique database in Canada because of its high spatio-temporal resolution. In order to provide some insight into the dominant processes at the McMaster Mesonet sites, a spatio-temporal and temporal stability analysis were conducted to identify spatio-temporal patterns in the data and to suggest some physical interpretation of soil moisture variability. It was found that the seasonal climate of the Great Lakes Basin causes a transition in soil moisture patterns at seasonal timescales. During winter and early spring months, and at the meadow sites, soil moisture distribution is governed by topographic redistribution, whereas following efflorescence in the spring and summer, soil moisture spatial distribution at the forested site was also controlled by vegetation canopy. Analysis of short-term temporal stability revealed that the relative difference between sites was maintained unless there was significant rainfall (> 20 mm or wet conditions a priori. Following a disturbance in the spatial soil moisture distribution due to wetting, the relative soil moisture pattern re-emerged in 18 to 24 h. Access to the McMaster Mesonet data can be provided by visiting www.hydrology.mcmaster.ca/mesonet.

  10. Key indicator tools for shallow slope failure assessment using soil chemical property signatures and soil colour variables.

    Science.gov (United States)

    Othman, Rashidi; Hasni, Shah Irani; Baharuddin, Zainul Mukrim; Hashim, Khairusy Syakirin Has-Yun; Mahamod, Lukman Hakim

    2017-10-01

    Slope failure has become a major concern in Malaysia due to the rapid development and urbanisation in the country. It poses severe threats to any highway construction industry, residential areas, natural resources and tourism activities. The extent of damages that resulted from this catastrophe can be lessened if a long-term early warning system to predict landslide prone areas is implemented. Thus, this study aims to characterise the relationship between Oxisols properties and soil colour variables to be manipulated as key indicators to forecast shallow slope failure. The concentration of each soil property in slope soil was evaluated from two different localities that consist of 120 soil samples from stable and unstable slopes located along the North-South Highway (PLUS) and East-West Highway (LPT). Analysis of variance established highly significant difference (P slope failure were high value of L*(62), low values of c* (20) and h* (66), low concentration of iron (53 mg kg-1) and aluminium oxide (37 mg kg-1), low soil TOC (0.5%), low CEC (3.6 cmol/kg), slightly acidic soil pH (4.9), high amount of sand fraction (68%) and low amount of clay fraction (20%).

  11. Global Soil Respiration: Interaction with Environmental Variables and Response to Climate Change

    Science.gov (United States)

    Jian, J.; Steele, M.

    2016-12-01

    Background, methods, objectivesTerrestrial ecosystems take up around 1.7 Pg C per year; however, the role of terrestrial ecosystems as a carbon sink may change to carbon source by 2050, as a result of positive feedback of soil respiration response to global warming. Nevertheless, limited evidence shows that soil carbon is decreasing and the role of terrestrial ecosystems is changing under warming. One possibility is the positive feedback may slow due to the acclimation of soil respiration as a result of decreasing temperature sensitivity (Q10) with warming. To verify and quantify the uncertainty in soil carbon cycling and feedbacks to climate change, we assembled soil respiration observations from 1961 to 2014 from 724 publications into a monthly global soil respiration database (MSRDB), which included 13482 soil respiration measurements together with 38 other ancillary measurements from 538 sites. Using this database we examined macroscale variation in the relationship between soil respiration and air temperature, precipitation, leaf area index and soil properties. We also quantified global soil respiration, the sources of uncertainty, and its feedback to warming based on climate region-oriented models with variant Q10function. Results and ConclusionsOur results showed substantial heterogeneity in the relationship between soil respiration and environmental factors across different climate regions. For example, soil respiration was strongly related to vegetation (via leaf area index) in colder regions, but not in tropical region. Only in tropical and arid regions did soil properties explain any variation in soil respiration. Global annual mean soil respiration from 1961 to 2014 was estimated to be 72.41 Pg C yr-1 based on monthly global soil respiration database, 25 Pg lower than estimated based on yearly soil respiration database. By using the variable Q10 models, we estimated that global soil respiration increased at a rate of 0.03 Pg C yr-1 from 1961 to 2014

  12. Incorporating soil variability in continental soil water modelling: a trade-off between data availability and model complexity

    Science.gov (United States)

    Peeters, L.; Crosbie, R. S.; Doble, R.; van Dijk, A. I. J. M.

    2012-04-01

    Developing a continental land surface model implies finding a balance between the complexity in representing the system processes and the availability of reliable data to drive, parameterise and calibrate the model. While a high level of process understanding at plot or catchment scales may warrant a complex model, such data is not available at the continental scale. This data sparsity is especially an issue for the Australian Water Resources Assessment system, AWRA-L, a land-surface model designed to estimate the components of the water balance for the Australian continent. This study focuses on the conceptualization and parametrization of the soil drainage process in AWRA-L. Traditionally soil drainage is simulated with Richards' equation, which is highly non-linear. As general analytic solutions are not available, this equation is usually solved numerically. In AWRA-L however, we introduce a simpler function based on simulation experiments that solve Richards' equation. In the simplified function soil drainage rate, the ratio of drainage (D) over storage (S), decreases exponentially with relative water content. This function is controlled by three parameters, the soil water storage at field capacity (SFC), the drainage fraction at field capacity (KFC) and a drainage function exponent (β). [ ] D- -S- S = KF C exp - β (1 - SFC ) To obtain spatially variable estimates of these three parameters, the Atlas of Australian Soils is used, which lists soil hydraulic properties for each soil profile type. For each soil profile type in the Atlas, 10 days of draining an initially fully saturated, freely draining soil is simulated using HYDRUS-1D. With field capacity defined as the volume of water in the soil after 1 day, the remaining parameters can be obtained by fitting the AWRA-L soil drainage function to the HYDRUS-1D results. This model conceptualisation fully exploits the data available in the Atlas of Australian Soils, without the need to solve the non

  13. Spatial and temporal soil water variability in the plowing horizon of agriculturally used soils in two regions of Southwest Germany

    Science.gov (United States)

    Poltoradnev, Maxim; Ingwersen, Joachim; Streck, Thilo

    2015-04-01

    Soil water dynamics plays an important role in soil-plant-atmosphere interactions. There is a lack of long-term continuous measurements of topsoil water content at the regional scale. The objective of the present study was to quantify and elucidate the seasonal dynamics of spatial soil water content variability in the plowing horizon (Ap) of agricultural soils at the regional scale. The study was conducted in the central part of the Kraichgau and the Mid Swabian Alb in Southwest Germany. In each region a soil water network embracing 21 stations was set up. All stations were installed on cropped agricultural sites and distributed across three spatial domains: an inner domain 3 km × 3 km (5 stations), a middle 9 km × 9 km (8 stations), and an outer domain 27 km × 27 km (8 stations). Each station consists of a TDT sensor (SI.99 Aquaflex Soil Moisture Sensor, Streat Instruments Ltd, New Zealand), which senses both soil water content and soil temperature, a rain gauge, and a remote transfer unit (RTU, datalogger + GSM modem), which stores and transfers data via GPRS modem to the central data server (Adcon Telemetry GmbH, Austria) located at the University of Hohenheim. The TDT sensors were installed at 0.15 m depth. A sensor consists of a three meter long and three centimeter wide flat transmission line. The relationship between the standard deviation (σθ) of the soil water content (SWC) and mean spatial soil water content () formed combinations of concave and convex hyperbolas. However, it strongly depended on SWC state and season. Generally, σθ was found to be changing along a convex trend during dry out and rewetting phases with a maximum in the intermediate SWC range. At the rain event scale, σθ() was either ascending or converging with decreasing . A concave shape was observed when approached to dry state. The majority of σθ() hysteresis loops were observed in intermediate and intermediate/wet state of SWC. All hysteretic loops were clockwise oriented

  14. Climate Change and Soil Texture Variability Impact on Soil Water Dynamic System of RUC Agricultural Field

    OpenAIRE

    Sheng, Zhang; Aliyevski, Faredin; Dong, Xu; Rongfeng, Fu; Kristensen, Suphap

    2007-01-01

    The main focus to make an understanding on a climate system is that it comprises with many compartments such as cryosphere, biosphere, atmosphere, land and ocean and all these compartments are interacted on each other and stimulates and drives the system by solar energy. The climate change condition express itself by increased air temperature and its impact on soil (agriculture and forest), hydrology and human beings. The main focus is the soil dynamic system and the basic know...

  15. Environmental controls on the spatial variability of soil water dynamics in a small watershed

    Science.gov (United States)

    Hu, Wei; Chau, Henry Wai; Qiu, Weiwen; Si, Bingcheng

    2017-08-01

    Soil water content (SWC) in the root zone is controlled by a suite of environmental variables. Complication arises from the cross-correlation between these environmental variables. Therefore, there is still a poor understanding on the controls of root zone SWC dynamics due, in part, to a lack of an appropriate method to untangle the controls. The objective of this study was to reveal the dominant controls of root zone soil water dynamics in a small watershed using an appropriate method based on empirical orthogonal function (EOF). For this purpose, SWC of 0-0.8 m layer in a small watershed on the Chinese Loess Plateau was used. The space-variant temporal anomaly (Rtn) of SWC, which is responsible for the spatial variability of soil water dynamics, was decomposed using the EOF. Results indicated that 86% of the total variations of Rtn were explained by three significant spatial structures (EOFs). Sand content and grass yield dominated the EOF1 of Rtn and elevation and aspect dominated EOF2 and EOF3 of Rtn , respectively. Moreover, their effects on soil water dynamics were time-dependent. The EOF analysis showed that three independent groups of factors (i.e., soil and vegetation dominated earth surface condition, elevation related near surface air humidity, and aspect regulated energy input) may drive the variability in soil water dynamics. Traditional correlation analysis, however, indicated that SWC was greater at higher elevation and sun-facing slopes, which distorted the soil water dynamics controls. Although original SWC-based partial correlation basically supported our findings, the results highly depended on the controlling factors selected. This study implied that Rtn rather than original SWC should be preferred for understanding soil water dynamics controls.

  16. Fine scale spatial variability of microbial pesticide degradation in soil: scales, controlling factors, and implications

    OpenAIRE

    Arnaud eDechesne; Nora eBadawi; Jens eAamand; Smets, Barth F.

    2014-01-01

    Pesticide biodegradation is a soil microbial function of critical importance for modern agriculture and its environmental impact. While it was once assumed that this activity was homogeneously distributed at the field scale, mounting evidence indicates that this is rarely the case. Here, we critically examine the literature on spatial variability of pesticide biodegradation in agricultural soil. We discuss the motivations, methods, and main findings of the primary literature. We found signifi...

  17. Study of the action of blast deck charge in rocky soils

    Directory of Open Access Journals (Sweden)

    Boiko V.V.

    2017-04-01

    Full Text Available Blasting (B in the industry, including the mining extraction of minerals, are carried out mostly with the use of blasthole charges that systematically distributed on the block that is undermined, by individual groups. The latter are blasted according to the scheme of short-delay firing (SDF through the intervals that are accepted not less than 20 Ms. Thus, the seismic effect of group charge explosion, consisting of individual blasthole charges and that actually is a group located charge determined by the formula of concentrated charge. Blast deck charges are effectively used in the driving of the trenches in the mining, formation of screens and cracks near the security objects. Only this method of performing blasting allows to define seismic effect in the transition from one diameter of a charge to another, as well as to determine the actual number of detonated charges in one group, which may differ from the calculated in drilling and blasting project. The work analyzes the physical essence of processes happened while blasting of blast deck charges. The effect of the orientation of the seismic action of blasting of blast deck charges towards the allocation line of charges is investigated. The results of generalized dependence of the speed of the displacement of the ground by the blast parameters and epicentral distance are obtained. We demonstrate with specific examples that blast deck charges that blasting simultaneously make a major chain of the career massive explosions at mining. Keywords: seismic fluctuations; the number of charges; the interaction of charges; the distance between the charges; the coefficients of the seismicity and the attenuation of the intensity of the waves; the unit charge; blast deck and blasthole charges; phase shifting; effective charge.

  18. Characterization of spatial variability of soil physicochemical properties and its impact on Rhodes grass productivity.

    Science.gov (United States)

    Tola, E; Al-Gaadi, K A; Madugundu, R; Zeyada, A M; Kayad, A G; Biradar, C M

    2017-02-01

    Characterization of soil properties is a key step in understanding the source of spatial variability in the productivity across agricultural fields. A study on a 16 ha field located in the eastern region of Saudi Arabia was undertaken to investigate the spatial variability of selected soil properties, such as soil compaction 'SC', electrical conductivity 'EC', pH (acidity or alkalinity of soil) and soil texture and its impact on the productivity of Rhodes grass (Chloris gayana L.). The productivity of Rhodes grass was investigated using the Cumulative Normalized Difference Vegetation Index (CNDVI), which was determined from Landsat-8 (OLI) images. The statistical analysis showed high spatial variability across the experimental field based on SC, clay and silt; indicated by values of the coefficient of variation (CV) of 22.08%, 21.89% and 21.02%, respectively. However, low to very low variability was observed for soil EC, sand and pH; with CV values of 13.94%, 7.20% and 0.53%, respectively. Results of the CNDVI of two successive harvests showed a relatively similar trend of Rhodes grass productivity across the experimental area (r = 0.74, p = 0.0001). Soil physicochemical layers of a considerable spatial variability (SC, clay, silt and EC) were utilized to delineate the experimental field into three management zones (MZ-1, MZ-2 and MZ-3); which covered 30.23%, 33.85% and 35.92% of the total area, respectively. The results of CNDVI indicated that the MZ-1 was the most productive zone, as its major areas of 50.28% and 45.09% were occupied by the highest CNDVI classes of 0.97-1.08 and 4.26-4.72, for the first and second harvests, respectively.

  19. Variability in Soil Moisture in a Temperate Deciduous Forest Using Electrical Resistivity and Throughfall Data

    Science.gov (United States)

    Ma, Y.; Van Dam, R. L.; Jayawickreme, D.

    2013-12-01

    In deciduous forests, soil moisture is an important driver of energy and carbon cycling, as well as ecosystem dynamics. The amount and distribution of soil moisture also influences soil microbial activity, nutrient fluxes, and groundwater recharge. Consequently, accurate characterization of interactions and interdependencies between vegetation and soil moisture is critical to forecast water resources and ecosystem health in a changing climate. Such relationships and processes are nevertheless difficult to measure, both in time and space because of our limited ability to monitor the subsurface at necessary scales and frequencies. Several recent studies have shown that electrical resistivity tomography (ERT), using an array of minimally invasive surface electrodes, is a promising method for in-situ soil moisture monitoring. To this point, however, only few studies have used ERT to investigate spatial variability of soil moisture in temperate deciduous forests and to explore any links between soil water and above ground ecosystem variables. In our study in a central Michigan (USA) maple forest during the 2012 growing season, we combined ERT with detailed vegetation surveys and throughfall measurements to obtain better insight into spatial variations in rainwater input and soil water patterns. Resistivity data were collected on a weekly basis along an array of 84 electrodes with a spacing of 1.5 m. The inversion results were temperature corrected, converted to soil moisture, and differenced to obtain 2D images of soil moisture changes. The throughfall data were obtained using a novel method based on dissolution of plaster-of-paris tablets that were positioned below funnels, at 19 locations in the forest. Our results show that: 1) resistivity changes spatially with vegetation distribution, 2) in-season temporal changes in resistivity are related to plant characteristics, in particular to tree count and basal area, and 3) our low-budget throughfall method was capable of

  20. Spatial variability of soil nutrient in paddy plantation: Sites FELCRA Seberang Perak

    Science.gov (United States)

    Kamarudin, H.; Adnan, N. A.; Mispan, M. R.; Athirah. A, A.

    2016-06-01

    The conventional methods currently used for rice cultivation in Malaysia are unable to give maximum yield although the yield production of paddy is increasing. This is due to the conversional method being unable to include soil properties as one of their parameters in agriculture management. Soil properties vary spatially in farm scale due to differences in topography, parent material, vegetation or land management and soil characteristics; also plantation productivity varies significantly over small spatial scales. Knowledge of spatial variability in soil fertility is important for site specific nutrient management. Analysis of spatial variability of soil nutrient of nitrogen (N), phosphorus (P) and potassium (K) were conducted in this study with the aid of GIS (i.e ArcGIS) and statistical softwares. In this study different temporal and depths of soil nutrient were extracted on the field and further analysis of N,P,K content were analysed in the chemical laboratory and using spatially technique in GIS sofware. The result indicated that for the Seberang Perak site of 58 hactares area, N and K are met minimum requirements nutrient content as outlines by the MARDI for paddy cultivation. However, P indicated poor condition in the study area; therefore the soil needs further attention and treatment.

  1. High-resolution mapping and spatial variability of soil organic carbon storage of permafrost-affected soils

    Science.gov (United States)

    Siewert, Matthias; Hugelius, Gustaf

    2017-04-01

    Permafrost-affected soils store large amounts of soil organic carbon (SOC). Mapping of this SOC provides a first order spatial input variable for research that relates carbon stored in permafrost regions to carbon cycle dynamics. High-resolution satellite imagery is becoming increasingly available even in circum-polar regions. The presented research highlights findings of high-resolution mapping efforts of SOC from five study areas in the northern circum-polar permafrost region. These study areas are located in Siberia (Kytalyk, Spasskaya Pad /Neleger, Lena delta), Northern Sweden (Abisko) and Northwestern Canada (Herschel Island). Our high spatial resolution analyses show how geomorphology has a strong influence on the distribution of SOC. This is organized at different spatial scales. Periglacial landforms and processes dictate local scale SOC distribution due to patterned ground. Such landforms are non-sorted circles and ice-wedge polygons of different age and scale. Palsas and peat plateaus are formed and can cover larger areas in Sub-Arctic environments. Study areas that have not been affected by Pleistocene glaciation feature ice-rich Yedoma sediments that dominate the local relief through thermokarst formation and create landscape scale macro environments that dictate the distribution of SOC. A general trend indicates higher SOC storage in Arctic tundra soils compared to forested Boreal or Sub-Arctic taiga soils. Yet, due to the shallower active layer depth in the Arctic, much of the SOC may be permanently frozen and thus not be available to ecosystem processes. Significantly more SOC is stored in soils compared to vegetation, indicating that vegetation growth and incorporation of the carbon into the plant phytomass alone will not be able to offset SOC released from permafrost. This contribution also addresses advances in thematic mapping methods and digital soil mapping of SOC in permafrost terrain. In particular machine-learning methods, such as support

  2. Heterogeneity of gaseous emissions in soils-spatial vs temporal variability

    Science.gov (United States)

    Cardenas, Laura; Chadwick, David; Misselbrook, Tom; Donovan, Neil; Dunn, Rob; Griffith, Bruce; Orr, Robert; Smith, Keith; Rees, Robert M.; Bell, Madeleine; Watson, Catherine; McGeough, Karen; McNeill, Gavin; Williams, John; Cloy, Joanna; Thorman, Rachel; Dhanoa, Dan

    2015-04-01

    Nitrous oxide (N2O) plays a dual role in the atmosphere as a greenhouse gas and via its influence on stratospheric ozone chemistry. The main source of N2O is agricultural soil, with an estimated 96 kt emitted from this source in the UK in 2012 (ca. 83% of the total UK N2O emissions). Microbial transformations such as nitrification, denitrification and chemodenitrification are responsible for these emissions. Soil texture and structure and land management practices (including presence of livestock) -- soil wetness, aeration, temperature and mineral N content -- influence the magnitude of the emissions. Heterogeneity in nutrient distribution and moisture, i.e. hot spots, create spatial variations in the main drivers of these transformations. Studies at laboratory scale are aimed to minimize the variability encountered in the field but although they provide important information on the controlling factors of the soil processes, they are not useful for real quantification. Daily and seasonal variation (temporal) in soil conditions (chemistry, physics and biology) and thus in emissions also occurs. This variability makes it a difficult challenge to quantify emissions and currently makes the soil source the largest contributor to the overall uncertainty of the UK greenhouse gas inventory. Here we present results of a statistical study on the variability of N2O emissions from measurements using the static chamber technique for a variety of N sources. Results from measurements using automated chambers are also presented. Part of the work was funded by the UK government to improve the quantification of this source by measuring emissions from sites with contrasting soil, climate and land management combinations. We also include results from measurements carried out with automated chambers on the UK National Capability Farm Platform in the South West of England. The results show that spatial variability largely contributes to the uncertainty of emissions but temporal

  3. Temporal Variability of Soil Respiration in Experimental Tree Plantations in Lowland Costa Rica

    Directory of Open Access Journals (Sweden)

    James W. Raich

    2017-02-01

    Full Text Available The principal objective of this study was to determine if there is consistent temporal variability in soil respiration from different forest plantations in a lowland tropical rainforest environment. Soil respiration was measured regularly over 2004 to 2010 in replicated plantations of 15- to 20-year-old evergreen tropical trees in lowland Costa Rica. Statistically significant but small differences in soil respiration were observed among hours of the day; daytime measurements were suitable for determining mean fluxes in this study. Fluxes varied more substantially among months, with the highest average emissions (5.9 μmol·m−2·s−1 occurring in September and low emissions (3.7 μmol·m−2·s−1 occurring in January. Three of the six tree species had significantly increasing rates of soil respiration across 2004–2010, with fluxes increasing at an average of 0.09 μmol·m−2·s−1 per year: the three other species had no long-term trends. It was hypothesized that there would be a tradeoff between carbon allocation aboveground, to produce new leaves, and belowground, to sustain roots and mycorrhizae, but the relationship between canopy leaf fall—a surrogate for canopy leaf flushing—and soil respiration was significantly positive. The similarities observed among temporal trends across plantation types, and significant relationships between soil respiration, soil water content and soil temperature, suggest that the physical environment largely controlled the temporal variability of soil respiration, but differences in flux magnitude among tree species were substantial and consistent across years.

  4. Selecting minimum dataset soil variables using PLSR as a regressive multivariate method

    Science.gov (United States)

    Stellacci, Anna Maria; Armenise, Elena; Castellini, Mirko; Rossi, Roberta; Vitti, Carolina; Leogrande, Rita; De Benedetto, Daniela; Ferrara, Rossana M.; Vivaldi, Gaetano A.

    2017-04-01

    Long-term field experiments and science-based tools that characterize soil status (namely the soil quality indices, SQIs) assume a strategic role in assessing the effect of agronomic techniques and thus in improving soil management especially in marginal environments. Selecting key soil variables able to best represent soil status is a critical step for the calculation of SQIs. Current studies show the effectiveness of statistical methods for variable selection to extract relevant information deriving from multivariate datasets. Principal component analysis (PCA) has been mainly used, however supervised multivariate methods and regressive techniques are progressively being evaluated (Armenise et al., 2013; de Paul Obade et al., 2016; Pulido Moncada et al., 2014). The present study explores the effectiveness of partial least square regression (PLSR) in selecting critical soil variables, using a dataset comparing conventional tillage and sod-seeding on durum wheat. The results were compared to those obtained using PCA and stepwise discriminant analysis (SDA). The soil data derived from a long-term field experiment in Southern Italy. On samples collected in April 2015, the following set of variables was quantified: (i) chemical: total organic carbon and nitrogen (TOC and TN), alkali-extractable C (TEC and humic substances - HA-FA), water extractable N and organic C (WEN and WEOC), Olsen extractable P, exchangeable cations, pH and EC; (ii) physical: texture, dry bulk density (BD), macroporosity (Pmac), air capacity (AC), and relative field capacity (RFC); (iii) biological: carbon of the microbial biomass quantified with the fumigation-extraction method. PCA and SDA were previously applied to the multivariate dataset (Stellacci et al., 2016). PLSR was carried out on mean centered and variance scaled data of predictors (soil variables) and response (wheat yield) variables using the PLS procedure of SAS/STAT. In addition, variable importance for projection (VIP

  5. Spatial variability of soil hydraulic properties on a steep slope in the loess plateau of China

    OpenAIRE

    Wei Hu; Ming An Shao; Quan Jiu Wang; Jun Fan; Klaus Reichardt

    2008-01-01

    The understanding of the structure of the spatial variability of soil surface hydraulic properties on steep slopes is important for modeling infiltration and runoff processes. The objective of this study was to investigate the spatial variability of these properties on a steep slope of the Loess Plateau in northwest China. A 9600 m² area was systematically sampled in a grid of 106 points spaced 10 m x 10 m. Hydraulic properties were determined with a disc infiltrometer under multiple pressure...

  6. Spatial variability of some soil properties varies in oil palm (Elaeis guineensis Jacq.) plantations of west coastal area of India

    Science.gov (United States)

    Behera, Sanjib Kumar; Suresh, Kancherla; Narsimha Rao, Bezawada; Mathur, Ravi Kumar; Shukla, Arvind Kumar; Manorama, Kamireddy; Ramachandrudu, Kummari; Harinarayana, Parasa; Prakash, Chandra

    2016-06-01

    Mapping spatial variability of soil properties is the key to efficient soil resource management for sustainable crop yield. Therefore, the present study was conducted to assess the spatial variability of soil properties such as acidity (pH), salinity (electrical conductivity (EC)), organic carbon, available K, available P, exchangeable Ca2+, exchangeable Mg2+, available S and hot water soluble B in surface (0-20 cm) and subsurface (20-40 cm) soil layers of oil palm plantations in south Goa district of Goa located in west coastal area of India. A total of 128 soil samples were collected from 64 oil palm plantations of Goa located at an approximate interval of 1-2 km and analyzed. Soil was acidic to neutral in reaction. Other soil properties varied widely in both the soil layers. Correlations between soil pH and exchangeable Ca2+, between soil EC and available K, between available P and available S and between exchangeable Ca2+ and exchangeable Mg2+ in both the soil layers were found to be positive and significant (P < 0.01). Geostatistical analysis revealed a varied spatial distribution pattern for the measured soil properties. Best-fit models for measured soil properties were exponential, Gaussian, stable, K-Bessel and spherical with moderate to strong spatial dependency. The results revealed that site-specific fertilizer management options needed to be adopted in the oil palm plantations of the study area owing to variability in soil properties.

  7. Assessment of soil nitrogen variability related to N doses applied through fertirrigation system.

    Science.gov (United States)

    Castellanos, M. T.; Tarquis, A. M.; Ribas, F.; Cabello, M. J.; Arce, A.; Cartagena, M. C.

    2009-04-01

    The knowledge of water and nitrogen dynamics in soils under drip irrigation and fertilizer application is essential to optimizing water and nitrogen management. Recent studies of water and nitrogen distribution in the soil under drip irrigation focus on water and inorganic nitrogen distribution around the drip emitters. Results of the studies are not verified with field experimental data. Reasons might include difficulties in obtaining field experimental data under irrigation and nitrogen fertilization [1]. N is an element which produces a stronger crop response, accelerates vegetative growth, plant development and yield increase. Accumulation and redistribution of N within the soil varies depending on management practices, soil characteristics, and growing season precipitation. Soil N high content at post-harvest is usually provided as evidence that N fertilizer had been applied in excess. The aim of this study is to characterize mineral N distribution in the soil profile measured at 5, 15, 25, 35, 45 and 55 cm of depth at the end of melon crop that received three N treatments: 93 (N93), 243 (N243) and 393 kg N ha-1(N393). The agronomic practices created a higher variability in soil Nitrogen content. NH4- N reduction in the soil profile can also be explained by the nitrification process. The high absorption and rapid nitrification of NH4+ ions in the plot layer are the main reason of a reduce movement downstream. NO3- ions present higher mobility in the soil profile. [1] Rahil, M.H.; Antonopoulos, V.Z. 2007. Simulating soil water flow and nitrogen dynamics in a sunflower field irrigated with reclaimed wastewater. Agricultural Water Management 92, 142 - 150. Acknowledgements: This project has been supported by INIA-RTA04-111

  8. Simulating soybean canopy temperature as affected by weather variables and soil water potential

    Science.gov (United States)

    Choudhury, B. J.

    1982-01-01

    Hourly weather data for several clear sky days during summer at Phoenix and Baltimore which covered a wide range of variables were used with a plant atmosphere model to simulate soybean (Glycine max L.) leaf water potential, stomatal resistance and canopy temperature at various soil water potentials. The air and dew point temperatures were found to be the significant weather variables affecting the canopy temperatures. Under identical weather conditions, the model gives a lower canopy temperature for a soybean crop with a higher rooting density. A knowledge of crop rooting density, in addition to air and dew point temperatures is needed in interpreting infrared radiometric observations for soil water status. The observed dependence of stomatal resistance on the vapor pressure deficit and soil water potential is fairly well represented. Analysis of the simulated leaf water potentials indicates overestimation, possibly due to differences in the cultivars.

  9. Areal variability of the mineral soil cover in a reclaimed soda waste dumping site

    Directory of Open Access Journals (Sweden)

    Klatka Sławomir

    2017-03-01

    Full Text Available Areal variability of the mineral soil cover in a reclaimed soda waste dumping site. This paper provides an analysis of the areal variability of the thickness and selected physical and chemical properties of the mineral cover formed in the process of settling ponds reclamation at the former Krakow Soda Plant “Solvay”. The topsoil is intended to provide a substrate for plants, therefore, its quality is the main determinant of the development for herbaceous and woody vegetation. Areal variability of the topsoil parameters was determined by kriging. In the context of the envisaged direction of management of the settling ponds, the analysis showed that electrical conductivity, thickness of the soil cover and the sand fraction content have potentially the highest impact on the diversification of vegetation. Understanding the spatial variability of the soil cover parameters, that are essential for vegetation, may contribute to increasing the efficiency of biological reclamation and also to cost reduction. Precise selection of the areas unsuitable for plant growth makes it possible to improve soil parameters on limited areas similarly as in the precision agriculture.

  10. Screening variability and change of soil moisture under wide-ranging climate conditions: Snow dynamics effects.

    Science.gov (United States)

    Verrot, Lucile; Destouni, Georgia

    2015-01-01

    Soil moisture influences and is influenced by water, climate, and ecosystem conditions, affecting associated ecosystem services in the landscape. This paper couples snow storage-melting dynamics with an analytical modeling approach to screening basin-scale, long-term soil moisture variability and change in a changing climate. This coupling enables assessment of both spatial differences and temporal changes across a wide range of hydro-climatic conditions. Model application is exemplified for two major Swedish hydrological basins, Norrström and Piteälven. These are located along a steep temperature gradient and have experienced different hydro-climatic changes over the time period of study, 1950-2009. Spatially, average intra-annual variability of soil moisture differs considerably between the basins due to their temperature-related differences in snow dynamics. With regard to temporal change, the long-term average state and intra-annual variability of soil moisture have not changed much, while inter-annual variability has changed considerably in response to hydro-climatic changes experienced so far in each basin.

  11. Variability of soil potential for biodegradation of petroleum hydrocarbons in a heterogeneous subsurface

    DEFF Research Database (Denmark)

    Kristensen, Andreas Houlberg; Poulsen, Tjalfe; Mortensen, Lars

    2010-01-01

    for biodegradation was highly variable, which from autoregressive state-space modeling was partly explained by changes in soil air-filled porosity and gravimetric water content. The results suggest considering biological heterogeneity when evaluating the fate of contaminants in the subsurface....

  12. Assessing the influence of land-use change on the variability of soil ...

    African Journals Online (AJOL)

    The study aimed at providing basis to consider spatial variability in soil fertility to inform effective decision making in mineral fertilizer recommendations. The study area was classified into six land-use categories using a rural rapid appraisal technique with the aid of the farmers in the community, and by remote sensing ...

  13. Spatial Variability of Physical Soil Quality Index of an Agricultural Field

    Directory of Open Access Journals (Sweden)

    Sheikh M. Fazle Rabbi

    2014-01-01

    Full Text Available A field investigation was carried out to evaluate the spatial variability of physical indicators of soil quality of an agricultural field and to construct a physical soil quality index (SQIP map. Surface soil samples were collected using 10  m×10 m grid from an Inceptisol on Ganges Tidal Floodplain of Bangladesh. Five physical soil quality indicators, soil texture, bulk density, porosity, saturated hydraulic conductivity (KS, and aggregate stability (measured as mean weight diameter, MWD were determined. The spatial structures of sand, clay, and KS were moderate but the structure was strong for silt, bulk density, porosity, and MWD. Each of the physical soil quality indicators was transformed into 0 and 1 using threshold criteria which are required for crop production. The transformed indicators were the combined into SQIP. The kriged SQIP map showed that the agricultural field studied could be divided into two parts having “good physical quality” and “poor physical soil quality.”

  14. Plant trait diversity buffers variability in denitrification potential over changes in season and soil conditions.

    Science.gov (United States)

    McGill, Bonnie M; Sutton-Grier, Ariana E; Wright, Justin P

    2010-07-16

    Denitrification is an important ecosystem service that removes nitrogen (N) from N-polluted watersheds, buffering soil, stream, and river water quality from excess N by returning N to the atmosphere before it reaches lakes or oceans and leads to eutrophication. The denitrification enzyme activity (DEA) assay is widely used for measuring denitrification potential. Because DEA is a function of enzyme levels in soils, most ecologists studying denitrification have assumed that DEA is less sensitive to ambient levels of nitrate (NO(3)(-)) and soil carbon and thus, less variable over time than field measurements. In addition, plant diversity has been shown to have strong effects on microbial communities and belowground processes and could potentially alter the functional capacity of denitrifiers. Here, we examined three questions: (1) Does DEA vary through the growing season? (2) If so, can we predict DEA variability with environmental variables? (3) Does plant functional diversity affect DEA variability? The study site is a restored wetland in North Carolina, US with native wetland herbs planted in monocultures or mixes of four or eight species. We found that denitrification potentials for soils collected in July 2006 were significantly greater than for soils collected in May and late August 2006 (pmoisture, organic matter, total inorganic nitrogen, and microbial biomass--none consistently explained the pattern observed in DEA through time. There was no significant relationship between DEA and plant species richness or functional diversity. However, the seasonal variance in microbial biomass standardized DEA rates was significantly inversely related to plant species functional diversity (pplant functional diversity may support a more constant level of DEA through time, buffering the ecosystem from changes in season and soil conditions.

  15. Spectral properties of rhodamine 3B adsorbed on the surface of montmorillonites with variable layer charge.

    Science.gov (United States)

    Bujdak, Juraj; Martínez, Virginia Martínez; Arbeloa, Fernando López; Iyi, Nobuo

    2007-02-13

    Montmorillonite was thermally treated at several temperatures to reduce the charge density of its layer surface. Absorption and fluorescence (steady-state and time-resolved) spectroscopies are now applied to study the adsorption of rhodamine 3B (R3B) laser dye in reduced charge montmorillonites (RCMs) in aqueous suspensions. The decrease in the charge density increases the intermolecular distance between adsorbed R3B molecules, reducing the tendency of the dye to self-associate. H-type and J-type aggregates of R3B in RCMs are spectroscopically characterized, the fluorescent J-aggregates being more extensively formed by decreasing the charge density. Both the reduction in the dye aggregation and the formation of J-type aggregates enhance the fluorescence efficiency of R3B dye adsorbed in montmorillonite particles. Absorption with linearly polarized light reveals that the H-aggregates are more disposed toward the perpendicular of the clay surface than the monomer and J-aggregates species.

  16. Assessing geotechnical centrifuge modelling in addressing variably saturated flow in soil and fractured rock.

    Science.gov (United States)

    Jones, Brendon R; Brouwers, Luke B; Van Tonder, Warren D; Dippenaar, Matthys A

    2017-05-01

    The vadose zone typically comprises soil underlain by fractured rock. Often, surface water and groundwater parameters are readily available, but variably saturated flow through soil and rock are oversimplified or estimated as input for hydrological models. In this paper, a series of geotechnical centrifuge experiments are conducted to contribute to the knowledge gaps in: (i) variably saturated flow and dispersion in soil and (ii) variably saturated flow in discrete vertical and horizontal fractures. Findings from the research show that the hydraulic gradient, and not the hydraulic conductivity, is scaled for seepage flow in the geotechnical centrifuge. Furthermore, geotechnical centrifuge modelling has been proven as a viable experimental tool for the modelling of hydrodynamic dispersion as well as the replication of similar flow mechanisms for unsaturated fracture flow, as previously observed in literature. Despite the imminent challenges of modelling variable saturation in the vadose zone, the geotechnical centrifuge offers a powerful experimental tool to physically model and observe variably saturated flow. This can be used to give valuable insight into mechanisms associated with solid-fluid interaction problems under these conditions. Findings from future research can be used to validate current numerical modelling techniques and address the subsequent influence on aquifer recharge and vulnerability, contaminant transport, waste disposal, dam construction, slope stability and seepage into subsurface excavations.

  17. Spatiotemporal predictions of soil properties and states in variably saturated landscapes

    Science.gov (United States)

    Franz, Trenton E.; Loecke, Terrance D.; Burgin, Amy J.; Zhou, Yuzhen; Le, Tri; Moscicki, David

    2017-07-01

    Understanding greenhouse gas (GHG) fluxes from landscapes with variably saturated soil conditions is challenging given the highly dynamic nature of GHG fluxes in both space and time, dubbed hot spots, and hot moments. On one hand, our ability to directly monitor these processes is limited by sparse in situ and surface chamber observational networks. On the other hand, remote sensing approaches provide spatial data sets but are limited by infrequent imaging over time. We use a robust statistical framework to merge sparse sensor network observations with reconnaissance style hydrogeophysical mapping at a well-characterized site in Ohio. We find that combining time-lapse electromagnetic induction surveys with empirical orthogonal functions provides additional environmental covariates related to soil properties and states at high spatial resolutions ( 5 m). A cross-validation experiment using eight different spatial interpolation methods versus 120 in situ soil cores indicated an 30% reduction in root-mean-square error for soil properties (clay weight percent and total soil carbon weight percent) using hydrogeophysical derived environmental covariates with regression kriging. In addition, the hydrogeophysical derived environmental covariates were found to be good predictors of soil states (soil temperature, soil water content, and soil oxygen). The presented framework allows for temporal gap filling of individual sensor data sets as well as provides flexible geometric interpolation to complex areas/volumes. We anticipate that the framework, with its flexible temporal and spatial monitoring options, will be useful in designing future monitoring networks as well as support the next generation of hyper-resolution hydrologic and biogeochemical models.

  18. Spatial Variability of Soil Characteristics along a Landscape Gradient in Bellanwila-Attidiya Area

    Directory of Open Access Journals (Sweden)

    S. Cooray

    2012-05-01

    Full Text Available Wetlands are comprised of unique components of soil, water and biodiversity which are interconnected. Although water and biodiversity components of wetlands are being somewhat investigated, a very few research have been carried out to investigate soil properties.This study focused on spatial variability of soil chemical and physical parameters in a land use gradient around the Bellanwila-Attidiya Sanctuary, This study was carried out for a period of 3 months and several random soil samples were obtained from all land use areas. Selected physical and chemical properties of soil were analyzed according to the Standard Methods and the GIS maps were developed using ArcView GIS 3.2. The results indicated that all chemical and physical parameters of soil varied across the land use gradient, except for temperature. According to the GIS maps there are apparent variations in distribution of soil properties. On the surface, the highest level of each parameter was found as follows: - NO3- – industrial area, PO4 3- - functioning paddy fields, SO4 2- - residential area, Cl- - residential area, Fe3+ - functioning paddy fields, moisture content - wetland, pH – industrial area, salinity- residential area, electrical conductivity – residential area. At a 1 m depth the pattern was different: NO3- – abandoned paddy fields, PO4 3- – functioning paddy fields, SO4 2- - wetland, Cl- - wetland, Fe3+ - residential area, moisture content - wetland, pH – industrial area, salinity - wetland, electrical conductivity - wetland. The findings clearly exhibit the increases in anthropogenic pressure have resulted in wide-scale alternation of soil properties, at least in the surface soil, across a land use gradient. Managing land use in the watershed of the wetland thus needs adequate attention to conserve this natural ecosystem.

  19. Spatial variability of detrended soil plow layer penetrometer resistance transect in a sugarcane field

    Science.gov (United States)

    Pérez, Luis D.; Cumbrera, Ramiro; Mato, Juan; Millán, Humberto; Tarquis, Ana M.

    2015-04-01

    Spatial variability of soil properties is relevant for identifying those zones with physical degradation. In this sense, one has to face the problem of identifying the origin and distribution of spatial variability patterns (Brouder et al., 2001; Millán et al., 2012). The objective of the present work was to quantify the spatial structure of soil penetrometer resistance (PR) collected from a transect data consisted of 221 points equidistant. In each sampling, readings were obtained from 0 cm till 70 cm of depth, with an interval of 5 cm (Pérez, 2012). The study was conducted on a Vertisol (Typic Hapludert) dedicated to sugarcane (Saccharum officinarum L.) production during the last sixty years (Pérez et al., 2010). Recently, scaling approach has been applied on the determination of the scaling data properties (Tarquis et al., 2008; Millán et al., 2012; Pérez, 2012). We focus in the Hurst analysis to characterize the data variability for each depth. Previously a detrended analysis was conducted in order to better study de intrinsic variability of the series. The Hurst exponent (H) for each depth was estimated showing a characteristic pattern and differentiating PR evolution in depth. References Brouder, S., Hofmann, B., Reetz, H.F., 2001. Evaluating spatial variability of soil parameters for input management. Better Crops 85, 8-11. Millán, H; AM Tarquís, Luís D. Pérez, Juan Mato, Mario González-Posada, 2012. Spatial variability patterns of some Vertisol properties at a field scale using standardized data. Soil and Tillage Research, 120, 76-84. Pérez, Luís D. 2012. Influencia de la maquinaria agrícola sobre la variabilidad espacial de la compactación del suelo. Aplicación de la metodología geoestadística-fractal. PhD thesis, UPM (In Spanish). Pérez, Luís D., Humberto Millán, Mario González-Posada 2010. Spatial complexity of soil plow layer penetrometer resistance as influenced by sugarcane harvesting: A prefractal approach. Soil and Tillage

  20. Addressing Geographic Variability in the Comparative Toxicity Potential of Copper and Nickel in Soils

    DEFF Research Database (Denmark)

    Owsianiak, Mikolaj; Rosenbaum, Ralph K.; Huijbregts, Mark A. J.

    2013-01-01

    Comparative toxicity potentials (CTP), in life cycle impact assessment also known as characterization factors (CF), of copper (Cu) and nickel (Ni) were calculated for a global set of 760 soils. An accessibility factor (ACF) that takes into account the role of the reactive, solid-phase metal pool......% geographic variability intervals are 1.4 × 103 (1.7 × 102 to 2.0 × 104) and 1.7 × 103 (2.1 × 102 to 1.1 × 104) m3/kg·day, respectively. The geographic variability of 3.5 orders of magnitude in the CTP of Cu is mainly associated with the variability in soil organic carbon and pH. They largely influence...

  1. Spatial variability of soil carbon stock in the Urucu river basin, Central Amazon-Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Ceddia, Marcos Bacis, E-mail: marcosceddia@gmail.com [Department of Soil, Institute of Agronomy, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, RJ 23890-000 (Brazil); Villela, André Luis Oliveira [Colégio Técnico da UFRRJ, RJ, Seropédica 23890-000 (Brazil); Pinheiro, Érika Flávia Machado [Department of Soil, Institute of Agronomy, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, RJ 23890-000 (Brazil); Wendroth, Ole [Department of Plant & Soil Sciences, University of Kentucky, College of Agriculture, Lexington, KY (United States)

    2015-09-01

    The Amazon Forest plays a major role in C sequestration and release. However, few regional estimates of soil organic carbon (SOC) stock in this ecoregion exist. One of the barriers to improve SOC estimates is the lack of recent soil data at high spatial resolution, which hampers the application of new methods for mapping SOC stock. The aims of this work were: (i) to quantify SOC stock under undisturbed vegetation for the 0–30 and the 0–100 cm under Amazon Forest; (ii) to correlate the SOC stock with soil mapping units and relief attributes and (iii) to evaluate three geostatistical techniques to generate maps of SOC stock (ordinary, isotopic and heterotopic cokriging). The study site is located in the Central region of Amazon State, Brazil. The soil survey covered the study site that has an area of 80 km{sup 2} and resulted in a 1:10,000 soil map. It consisted of 315 field observations (96 complete soil profiles and 219 boreholes). SOC stock was calculated by summing C stocks by horizon, determined as a product of BD, SOC and the horizon thickness. For each one of the 315 soil observations, relief attributes were derived from a topographic map to understand SOC dynamics. The SOC stocks across 30 and 100 cm soil depth were 3.28 and 7.32 kg C m{sup −2}, respectively, which is, 34 and 16%, lower than other studies. The SOC stock is higher in soils developed in relief forms exhibiting well-drained soils, which are covered by Upland Dense Tropical Rainforest. Only SOC stock in the upper 100 cm exhibited spatial dependence allowing the generation of spatial variability maps based on spatial (co)-regionalization. The CTI was inversely correlated with SOC stock and was the only auxiliary variable feasible to be used in cokriging interpolation. The heterotopic cokriging presented the best performance for mapping SOC stock. - Highlights: • The SOC stocks across 30 and 100 cm depth were 3.28 and 7.32 kg C m{sup −2}, respectively. • SOC stocks were 34 and 16

  2. Latin Hypercube Sampling (LHS) at variable resolutions for enhanced watershed scale Soil Sampling and Digital Soil Mapping.

    Science.gov (United States)

    Hamalainen, Sampsa; Geng, Xiaoyuan; He, Juanxia

    2017-04-01

    Latin Hypercube Sampling (LHS) at variable resolutions for enhanced watershed scale Soil Sampling and Digital Soil Mapping. Sampsa Hamalainen, Xiaoyuan Geng, and Juanxia, He. AAFC - Agriculture and Agr-Food Canada, Ottawa, Canada. The Latin Hypercube Sampling (LHS) approach to assist with Digital Soil Mapping has been developed for some time now, however the purpose of this work was to complement LHS with use of multiple spatial resolutions of covariate datasets and variability in the range of sampling points produced. This allowed for specific sets of LHS points to be produced to fulfil the needs of various partners from multiple projects working in the Ontario and Prince Edward Island provinces of Canada. Secondary soil and environmental attributes are critical inputs that are required in the development of sampling points by LHS. These include a required Digital Elevation Model (DEM) and subsequent covariate datasets produced as a result of a Digital Terrain Analysis performed on the DEM. These additional covariates often include but are not limited to Topographic Wetness Index (TWI), Length-Slope (LS) Factor, and Slope which are continuous data. The range of specific points created in LHS included 50 - 200 depending on the size of the watershed and more importantly the number of soil types found within. The spatial resolution of covariates included within the work ranged from 5 - 30 m. The iterations within the LHS sampling were run at an optimal level so the LHS model provided a good spatial representation of the environmental attributes within the watershed. Also, additional covariates were included in the Latin Hypercube Sampling approach which is categorical in nature such as external Surficial Geology data. Some initial results of the work include using a 1000 iteration variable within the LHS model. 1000 iterations was consistently a reasonable value used to produce sampling points that provided a good spatial representation of the environmental

  3. Characterization of spatial soil variability and its effect on Millet yield on Sudano-Sahelian coversands in SW Niger

    NARCIS (Netherlands)

    Voortman, R.L.; Brouwer, J.; Albersen, P.J.

    2004-01-01

    Very local spatial soil variability on Sudano-Sahelian coversands hampers the interpretation of agronomic research and is an obstacle for the dissemination of research findings. In an earlier paper, we specifically accounted for this spatial soil variability: Using novel tools for data exploration,

  4. Spatial aggregation for crop modelling at regional scales: the effects of soil variability

    Science.gov (United States)

    Coucheney, Elsa; Villa, Ana; Eckersten, Henrik; Hoffmann, Holger; Jansson, Per-Erik; Gaiser, Thomas; Ewert, Franck; Lewan, Elisabet

    2017-04-01

    Modelling agriculture production and adaptation to the environment at regional or global scale receives much interest in the context of climate change. Process-based soil-crop models describe the flows of mass (i.e. water, carbon and nitrogen) and energy in the soil-plant-atmosphere system. As such, they represent valuable tools for predicting agricultural production in diverse agro-environmental contexts as well as for assessing impacts on the environment; e.g. leaching of nitrates, changes in soil carbon content and GHGs emissions. However, their application at regional and global scales for climate change impact studies raises new challenges related to model input data, calibration and evaluation. One major concern is to take into account the spatial variability of the environmental conditions (e.g. climate, soils, management practices) used as model input and because the impacts of climate change on cropping systems depend strongly on the site conditions and properties (1). For example climate change effects on yield can be either negative or positive depending on the soil type (2). Additionally, the use of different methods of upscaling and downscaling adds new sources of modelling uncertainties (3). In the present study, the effect of aggregating soil input data by area majority of soil mapping units was explored for spatially gridded simulations with the soil-vegetation model CoupModel for a region in Germany (North Rhine-Westphalia, NRW). The data aggregation effect (DAE) was analysed for wheat yield, water drainage, soil carbon mineralisation and nitrogen leaching below the root zone. DAE was higher for soil C and N variables than for yield and drainage and were strongly related to the spatial coverage of specific soils within the study region. These 'key soils' were identified by a model sensitivity analysis to soils present in the NRW region. The spatial aggregation of the key soils additionally influenced the DAE. Our results suggest that a spatial

  5. Amplification and dampening of soil respiration by changes in temperature variability

    Directory of Open Access Journals (Sweden)

    C. A. Sierra

    2011-04-01

    Full Text Available Accelerated release of carbon from soils is one of the most important feedbacks related to anthropogenically induced climate change. Studies addressing the mechanisms for soil carbon release through organic matter decomposition have focused on the effect of changes in the average temperature, with little attention to changes in temperature variability. Anthropogenic activities are likely to modify both the average state and the variability of the climatic system; therefore, the effects of future warming on decomposition should not only focus on trends in the average temperature, but also variability expressed as a change of the probability distribution of temperature. Using analytical and numerical analyses we tested common relationships between temperature and respiration and found that the variability of temperature plays an important role determining respiration rates of soil organic matter. Changes in temperature variability, without changes in the average temperature, can affect the amount of carbon released through respiration over the long-term. Furthermore, simultaneous changes in the average and variance of temperature can either amplify or dampen the release of carbon through soil respiration as climate regimes change. These effects depend on the degree of convexity of the relationship between temperature and respiration and the magnitude of the change in temperature variance. A potential consequence of this effect of variability would be higher respiration in regions where both the mean and variance of temperature are expected to increase, such as in some low latitude regions; and lower amounts of respiration where the average temperature is expected to increase and the variance to decrease, such as in northern high latitudes.

  6. Variability of soil fertility properties in areas planted to sugarcane in the State of Goias, Brazil

    Directory of Open Access Journals (Sweden)

    José Avelino Cardoso

    2014-04-01

    Full Text Available Soil sampling should provide an accurate representation of a given area so that recommendations for amendments of soil acidity, fertilization and soil conservation may be drafted to increase yield and improve the use of inputs. The aim of this study was to evaluate the variability of soil fertility properties of Oxisols in areas planted to sugarcane in the State of Goias, Brazil. Two areas of approximately 8,100 m² each were selected, representing two fields of the Goiasa sugarcane mill in Goiatuba. The sugarcane crop had a row spacing of 1.5 m and subsamples were taken from 49 points in the row and 49 between the row with a Dutch auger at depths of 0.0-0.2 and 0.2-0.4 m, for a total of 196 subsamples for each area. The samples were individually subjected to chemical analyses of soil fertility (pH in CaCl2, potential acidity, organic matter, P, K, Ca and Mg and particle size analysis. The number of subsamples required to compose a sample within the acceptable ranges of error of 5, 10, 20 and 40 % of each property were computed from the coefficients of variation and the Student t-value for 95 % confidence. The soil properties under analysis exhibited different variabilities: high (P and K, medium (potential acidity, Ca and Mg and low (pH, organic matter and clay content. Most of the properties analyzed showed an error of less than 20 % for a group of 20 subsamples, except for P and K, which were capable of showing an error greater than 40 % around the mean. The extreme variability in phosphorus, particularly at the depth of 0.2-0.4 m, attributed to banded application of high rates of P fertilizers at planting, places limitations on assessment of its availability due to the high number of subsamples required for a composite sample.

  7. Soil Carbon Variability and Change Detection in the Forest Inventory Analysis Database of the United States

    Science.gov (United States)

    Wu, A. M.; Nater, E. A.; Dalzell, B. J.; Perry, C. H.

    2014-12-01

    The USDA Forest Service's Forest Inventory Analysis (FIA) program is a national effort assessing current forest resources to ensure sustainable management practices, to assist planning activities, and to report critical status and trends. For example, estimates of carbon stocks and stock change in FIA are reported as the official United States submission to the United Nations Framework Convention on Climate Change. While the main effort in FIA has been focused on aboveground biomass, soil is a critical component of this system. FIA sampled forest soils in the early 2000s and has remeasurement now underway. However, soil sampling is repeated on a 10-year interval (or longer), and it is uncertain what magnitude of changes in soil organic carbon (SOC) may be detectable with the current sampling protocol. We aim to identify the sensitivity and variability of SOC in the FIA database, and to determine the amount of SOC change that can be detected with the current sampling scheme. For this analysis, we attempt to answer the following questions: 1) What is the sensitivity (power) of SOC data in the current FIA database? 2) How does the minimum detectable change in forest SOC respond to changes in sampling intervals and/or sample point density? Soil samples in the FIA database represent 0-10 cm and 10-20 cm depth increments with a 10-year sampling interval. We are investigating the variability of SOC and its change over time for composite soil data in each FIA region (Pacific Northwest, Interior West, Northern, and Southern). To guide future sampling efforts, we are employing statistical power analysis to examine the minimum detectable change in SOC storage. We are also investigating the sensitivity of SOC storage changes under various scenarios of sample size and/or sample frequency. This research will inform the design of future FIA soil sampling schemes and improve the information available to international policy makers, university and industry partners, and the public.

  8. Grain boundary-induced variability of charge transport in hydrogenated polycrystalline graphene

    DEFF Research Database (Denmark)

    Barrios-Vargas, Jose E.; Falkenberg, Jesper Toft; Soriano, David

    2017-01-01

    Chemical functionalization has proven to be a promising means of tailoring the unique properties of graphene. For example, hydrogenation can yield a variety of interesting effects, including a metal-insulator transition or the formation of localized magnetic moments. Meanwhile, graphene grown...... by chemical vapor deposition is the most suitable for large-scale production, but the resulting material tends to be polycrystalline. Up to now there has been relatively little focus on how chemical functionalization, and hydrogenation in particular, impacts the properties of polycrystalline graphene....... In this work, we use numerical simulations to study the electrical properties of hydrogenated polycrystalline graphene. We find a strong correlation between the spatial distribution of the hydrogen adsorbates and the charge transport properties. Charge transport is weakly sensitive to hydrogenation when...

  9. Predicting infectivity of Arbuscular Mycorrhizal fungi from soil variables using Generalized Additive Models and Generalized Linear Models

    Directory of Open Access Journals (Sweden)

    IRNANDA AIKO FIFI DJUUNA

    2010-07-01

    Full Text Available Djuuna IAF, Abbott LK, Van Niel K (2010 Predicting infectivity of Arbuscular Mycorrhizal fungi from soil variables using Generalized Additive Models and Generalized Linear Models. Biodiversitas 11: 145-150. The objective of this study was to predict the infectivity of arbuscular mycorrhizal fungi (AM fungi, from field soil based on soil properties and land use history using generalized additive models (GAMs and generalized linear models (GLMs. A total of 291 soil samples from a farm in Western Australia near Wickepin were collected and used in this study. Nine soil properties, including elevation, pH, EC, total C, total N, P, K, microbial biomass carbon, and soil texture, and land use history of the farm were used as independent variables, while the percentage of root length colonized (%RLC was used as the dependent variable. GAMs parameterized for the percent of root length colonized suggested skewed quadratic responses to soil pH and microbial biomass carbon; cubic responses to elevation and soil K; and linear responses to soil P, EC and total C. The strength of the relationship between percent root length colonized by AM fungi and environmental variables showed that only elevation, total C and microbial biomass carbon had strong relationships. In general, GAMs and GLMs models confirmed the strong relationship between infectivity of AM fungi (assessed in a glasshouse bioassay for soil collected in summer prior to the first rain of the season and soil properties.

  10. Small-scale spatial variability of atrazine and dinoseb adsorption parameters in an alluvial soil.

    Science.gov (United States)

    Mermoud, A; Martins, J M F; Zhang, D; Favre, A C

    2008-01-01

    Soil sorption processes largely control the environmental fate of herbicides. Therefore, accuracy of sorption parameters is crucial for accurate prediction of herbicide mobility in agricultural soils. A combined experimental and statistical study was performed to investigate the small-scale spatial variability of sorption parameters for atrazine and dinoseb in soils and to establish the number of samples needed to provide a value of the distribution coefficient (K(d)) next to the mean, with a given precision. The study explored sorption properties of the two herbicides in subsurface samples collected from four pits distributed along a transect of an alluvial soil; two to four samples were taken at about 30 cm apart at each sampling location. When considering all the data, the distribution coefficients were found to be normally and log-normally distributed for atrazine and dinoseb, respectively; the CVs were relatively high (close to 50% for dinoseb and 40% for atrazine). When analyzed horizon by horizon, the data revealed distribution coefficients normally distributed for both herbicides, whatever the soil layer, with lower CVs. The K(d) values were shown to vary considerably between samples collected at very short distance (a few centimeters), suggesting that taking a single soil sample to determine sorption properties through batch experiments can lead to highly unrepresentative results and to poor sorption/mobility predictions.

  11. Spatial variability of microbial biomass and organic matter labile pools in a haplic planosol soil

    Directory of Open Access Journals (Sweden)

    Diego Campana Loureiro

    2010-01-01

    Full Text Available The objective of this work was to study the spatial variability of soil microbial biomass (SMB and labile soil organic matter pools (labile SOM, under different management systems and plant cover. The experiment was conducted in a Haplic Planosol soil on an Integrated Agroecological Production System (SIPA, in Seropédica, Rio de Janeiro. The evaluated management systems were: alley cropping, pasture, and bush garden, the late one was used as reference area. Three grids of regular spacing of 2.5 x 2.5 meters were used for sampling, consisting of 25 georeferenced points each, where soil samples were taken at 0-10 cm depth. The following labile constituents of soil organic matter were determined: free light fraction (FLF, water soluble C and N, C and N of SMB (SMB-C and SMB-N, and glomalin content. The textural fractions (sand, silt, and clay, pH in water, and chemical attributes (organic C, total N, Ca, Mg, Al, P, K, and CEC-cation exchange capacity were also determined. The areas of alley cropping and pasture showed spatial dependence to the attributes of SOM. The occurrence of high spatial dependence for the attributes associated to microbial biomass in the alley cropping system (C, FLF, SMB-N and respiration, probably was due to external factors related to management, such as: intensive rotational cropping system, diversity of crops and different inputs of organic matter to soil such as pruning material and organic compost.

  12. Agriculture at the Edge: Landscape Variability of Soil C Stocks and Fluxes in the Tropical Andes

    Science.gov (United States)

    Riveros-Iregui, D. A.; Peña, C.

    2015-12-01

    Paramos, or tropical alpine grasslands occurring right above the forest tree-line (2,800 - 4,700 m), are among the most transformed landscapes in the humid tropics. In the Tropical Andes, Paramos form an archipelago-like pattern from Northern Colombia to Central Peru that effectively captures atmospheric moisture originated in the Amazon-Orinoco basins, while marking the highest altitude capable of sustaining vegetation growth (i.e., 'the edge'). This study investigates the role of land management on mediating soil carbon stocks and fluxes in Paramo ecosystems of the Eastern Cordillera of Colombia. Observations were collected at a Paramo site strongly modified by land use change, including active potato plantations, pasture, tillage, and land abandonment. Results show that undisturbed Paramos soils have high total organic carbon (TOC), high soil water content (SWC), and low soil CO2 efflux (RS) rates. However, Paramo soils that experience human intervention show lower TOC, higher and more variable RS rates, and lower SWC. This study demonstrates that changes in land use in Paramos affect differentially the accumulation and exchange of soil carbon with the atmosphere and offers implications for management and protection strategies of what has been deemed the fastest evolving biodiversity ecosystem in the world.

  13. Unsaturated Frozen Soil Permeability Coefficient Test and Analysis Under the Condition of Variable Porosity

    Directory of Open Access Journals (Sweden)

    GAO Yu

    2017-06-01

    Full Text Available Frozen soil permeability is one of the key issues in the process of frozen soil water properties research due to special hydrological phenomenon caused by the change of frozen soil water properties. In order to study the effect of ice content and dry density on non - closed porosity and permeability of unsaturated frozen soils, choose ice content ( 2% ,4% ,6% ,8% ,10% ,12% ,14% ,16% ,18% ,20% and dry sample density ( 1. 4 × 103 kg /m3 ,1. 5 × 103 kg /m3 and 1. 6 × 103 kg /m3 as a single variable factor to measure frozen soil permeability coefficient. The water level test method was used to determine the permeability coefficient of frozen soil,and the experimental study on the permeability coefficient of unsaturated frozen soil was carried out. The results show that the permeability coefficient and the unclosed porosity of the unsaturated frozen soil are smaller with the increase of the ice content and dry sample density,and the range is 0. 19 - 0. 714 and 8. 55 - 19. 18 m / d. When the ice content is 20% and the dry density of the sample is 1. 6 × 103 kg /m3 ,the minimum unsaturated permafrost permeability coefficient is 8. 55 m / d and the minimum unclosed porosity is 0. 19.

  14. Soil microbial community response to drought and precipitation variability in the Chihuahuan Desert.

    Science.gov (United States)

    Clark, Jeb S; Campbell, James H; Grizzle, Heath; Acosta-Martìnez, Veronica; Zak, John C

    2009-02-01

    Increases in the magnitude and variability of precipitation events have been predicted for the Chihuahuan Desert region of West Texas. As patterns of moisture inputs and amounts change, soil microbial communities will respond to these alterations in soil moisture windows. In this study, we examined the soil microbial community structure within three vegetation zones along the Pine Canyon Watershed, an elevation and vegetation gradient in Big Bend National Park, Chihuahuan Desert. Soil samples at each site were obtained in mid-winter (January) and in mid-summer (August) for 2 years to capture a component of the variability in soil temperature and moisture that can occur seasonally and between years along this watershed. Precipitation patterns and amounts differed substantially between years with a drought characterizing most of the second year. Soils were collected during the drought period and following a large rainfall event and compared to soil samples collected during a relatively average season. Structural changes within microbial community in response to site, season, and precipitation patterns were evaluated using fatty acid methyl ester (FAME) and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analyses. Fungal FAME amounts differed significantly across seasons and sites and greatly outweighed the quantity of bacterial and actinomycete FAME levels for all sites and seasons. The highest fungal FAME levels were obtained in the low desert scrub site and not from the high elevation oak-pine forests. Total bacterial and actinomycete FAME levels did not differ significantly across season and year within any of the three locations along the watershed. Total bacterial and actinomycete FAME levels in the low elevation desert-shrub and grassland sites were slightly higher in the winter than in the summer. Microbial community structure at the high elevation oak-pine forest site was strongly correlated with levels of NH4+-N, % soil moisture

  15. Using Environmental Variables for Studying of the Quality of Sampling in Soil Mapping

    Directory of Open Access Journals (Sweden)

    A. Jafari

    2016-02-01

    profiles, which were then described, sampled, analyzed and classified according to the USDA soil classification system (16. The basic rationale is to set up a hypercube, the axes of which are the quantiles of rasters of environmental covariates, e.g., digital elevation model. Sampling evaluation was made using the HELS algorithm. This algorithm was written based on the study of Carre et al., 2007 (3 and run in R. Results and Discussion: The covariate dataset is represented by elevation, slope and wetness index (Table 2. All data layers were interpolated to a common grid of 30 m resolution. The size of the raster layer is 421 by 711 grid cells. Each of the three covariates is divided into four quantiles (Table 2. The hypercube character space has 43, i.e. 64 strata (Figure 5. The average number of grid cells within each stratum is therefore 4677 grid cells. The map of the covariate index (Figure 6 shows some patterns representative of the covariate variability. The values of the covariate index range between 0.0045 and 5.95. This means that some strata are very dense compared to others. This index allows us to explain if high or low relative weight of the sampling units (see below is due to soil sampling or covariate density. The strata with the highest density are in the areas with high geomorphology diversity. It means that geomorphology processes can cause the diversity and variability and it is in line with the geomorphology map (Figure 2. Of the 64 strata, 30.4% represent under-sampling, 60.2% represent adequate sampling and 9.4% represent over-sampling. Regarding the covariate index, most of the under-sampling appears in the high covariate index, where soil covariates are then highly variable. Actually, it is difficult to collect field samples in these highly variable areas (Figure 7. Also, most of the over-sampling was observed in areas with alow covariate index (Figure 7. We calculated the weights of all the sampling units and showed the results in Figure 8. One 64

  16. Trace metal pyritization variability in response to mangrove soil aerobic and anaerobic oxidation processes.

    Science.gov (United States)

    Machado, W; Borrelli, N L; Ferreira, T O; Marques, A G B; Osterrieth, M; Guizan, C

    2014-02-15

    The degree of iron pyritization (DOP) and degree of trace metal pyritization (DTMP) were evaluated in mangrove soil profiles from an estuarine area located in Rio de Janeiro (SE Brazil). The soil pH was negatively correlated with redox potential (Eh) and positively correlated with DOP and DTMP of some elements (Mn, Cu and Pb), suggesting that pyrite oxidation generated acidity and can affect the importance of pyrite as a trace metal-binding phase, mainly in response to spatial variability in tidal flooding. Besides these aerobic oxidation effects, results from a sequential extraction analyses of reactive phases evidenced that Mn oxidized phase consumption in reaction with pyrite can be also important to determine the pyritization of trace elements. Cumulative effects of these aerobic and anaerobic oxidation processes were evidenced as factors affecting the capacity of mangrove soils to act as a sink for trace metals through pyritization processes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Fine scale spatial variability of microbial pesticide degradation in soil: scales, controlling factors, and implications

    DEFF Research Database (Denmark)

    Dechesne, Arnaud; Badawi, N.; Aamand, Jens

    2014-01-01

    Pesticide biodegradation is a soil microbial function of critical importance for modern agriculture and its environmental impact. While it was once assumed that this activity was homogeneously distributed at the field scale, mounting evidence indicates that this is rarely the case. Here, we...... critically examine the literature on spatial variability of pesticide biodegradation in agricultural soil. We discuss the motivations, methods, and main findings of the primary literature. We found significant diversity in the approaches used to describe and quantify spatial heterogeneity, which complicates...... across pesticide classes: they include some soil characteristics (pH) and some agricultural management practices (pesticide application, tillage), while other potential controlling factors have more conflicting effects depending on the site or the pesticide. Evidence demonstrating the importance...

  18. Variable-range electron hopping, conductivity cross-over and space-charge relaxation in C60Br6

    OpenAIRE

    Manesh, Zachariah; Romanini, Michela; Zygouri, Panagiota; Gournis, Dimitrios; Tamarit Mur, José Luis; Barrio Casado, María del; Macovez, Roberto

    2016-01-01

    Dielectric spectroscopy is employed to probe the frequency-dependent conductivity and dipolar dielectric response of solid C60Br6. Below approximately 215 K, charge conduction is electronic and well described by Mott's variable-range polaron hopping model, with effective hopping activation energy Ea varying between 0.12 eV at 125 K and 0.16 eV at 220 K, and most probable hopping range varying between 100 and 125% of the decay length of the localized polaron's wavefunction. Above 215 K a new c...

  19. Fine scale spatial variability of microbial pesticide degradation in soil: scales, controlling factors, and implications

    Science.gov (United States)

    Dechesne, Arnaud; Badawi, Nora; Aamand, Jens; Smets, Barth F.

    2014-01-01

    Pesticide biodegradation is a soil microbial function of critical importance for modern agriculture and its environmental impact. While it was once assumed that this activity was homogeneously distributed at the field scale, mounting evidence indicates that this is rarely the case. Here, we critically examine the literature on spatial variability of pesticide biodegradation in agricultural soil. We discuss the motivations, methods, and main findings of the primary literature. We found significant diversity in the approaches used to describe and quantify spatial heterogeneity, which complicates inter-studies comparisons. However, it is clear that the presence and activity of pesticide degraders is often highly spatially variable with coefficients of variation often exceeding 50% and frequently displays non-random spatial patterns. A few controlling factors have tentatively been identified across pesticide classes: they include some soil characteristics (pH) and some agricultural management practices (pesticide application, tillage), while other potential controlling factors have more conflicting effects depending on the site or the pesticide. Evidence demonstrating the importance of spatial heterogeneity on the fate of pesticides in soil has been difficult to obtain but modeling and experimental systems that do not include soil's full complexity reveal that this heterogeneity must be considered to improve prediction of pesticide biodegradation rates or of leaching risks. Overall, studying the spatial heterogeneity of pesticide biodegradation is a relatively new field at the interface of agronomy, microbial ecology, and geosciences and a wealth of novel data is being collected from these different disciplinary perspectives. We make suggestions on possible avenues to take full advantage of these investigations for a better understanding and prediction of the fate of pesticides in soil. PMID:25538691

  20. Grain boundary-induced variability of charge transport in hydrogenated polycrystalline graphene

    Science.gov (United States)

    Barrios Vargas, Jose E.; Toft Falkenberg, Jesper; Soriano, David; Cummings, Aron W.; Brandbyge, Mads; Roche, Stephan

    2017-06-01

    Chemical functionalization has proven to be a promising means of tailoring the unique properties of graphene. For example, hydrogenation can yield a variety of interesting effects, including a metal-insulator transition or the formation of localized magnetic moments. Meanwhile, graphene grown by chemical vapor deposition is the most suitable for large-scale production, but the resulting material tends to be polycrystalline. Up to now there has been relatively little focus on how chemical functionalization, and hydrogenation in particular, impacts the properties of polycrystalline graphene. In this work, we use numerical simulations to study the electrical properties of hydrogenated polycrystalline graphene. We find a strong correlation between the spatial distribution of the hydrogen adsorbates and the charge transport properties. Charge transport is weakly sensitive to hydrogenation when adsorbates are confined to the grain boundaries, while a uniform distribution of hydrogen degrades the electronic mobility. This difference stems from the formation of the hydrogen-induced resonant impurity states, which are inhibited when the honeycomb symmetry is locally broken by the grain boundaries. These findings suggest a tunability of electrical transport of polycrystalline graphene through selective hydrogen functionalization, and also have implications for hydrogen-induced magnetization and spin lifetime of this material.

  1. Relation of pH and other soil variables to concentrations of Pb, Cu, Zn, Cd, and Se in earthworms

    Science.gov (United States)

    Beyer, W.N.; Hensler, G.L.; Moore, J.

    1987-01-01

    Various soil treatments (clay, composted peat, superphosphate, sulfur, calcium carbonate, calcium chloride, zinc chloride, selenous acid) were added to experimental field plots to test the effect of different soil variables on the concentrations of 5 elements in earthworms (Pb, Cu, Zn, Cd, Se). Concentrations of the 5 elements were related to 9 soil variables (soil Pb, soil Cu, soil Zn, pH, organic matter, P, K, Mg, and Ca) with linear multiple regression. Lead concentrations in earthworms were positively correlated with soil Pb and soil organic matter, and negatively correlated with soil pH and soil Mg, with an R2 of 64%. Se concentrations were higher in earthworms from plots amended with Se, and Zn concentrations were higher in earthworms from plots amended with Zn. However, none of the other soil variables had important effects on the concentrations of Cu, Zn, Cd and Se in earthworms. Although some significant statistical relations were demonstrated, the values of r2 of all relations (> 20%) were so low that they had little predictive value.

  2. Quantifying Spatial Variability of Selected Soil Trace Elements and Their Scaling Relationships Using Multifractal Techniques

    Science.gov (United States)

    Zhang, Fasheng; Yin, Guanghua; Wang, Zhenying; McLaughlin, Neil; Geng, Xiaoyuan; Liu, Zuoxin

    2013-01-01

    Multifractal techniques were utilized to quantify the spatial variability of selected soil trace elements and their scaling relationships in a 10.24-ha agricultural field in northeast China. 1024 soil samples were collected from the field and available Fe, Mn, Cu and Zn were measured in each sample. Descriptive results showed that Mn deficiencies were widespread throughout the field while Fe and Zn deficiencies tended to occur in patches. By estimating single multifractal spectra, we found that available Fe, Cu and Zn in the study soils exhibited high spatial variability and the existence of anomalies ([α(q)max−α(q)min]≥0.54), whereas available Mn had a relatively uniform distribution ([α(q)max−α(q)min]≈0.10). The joint multifractal spectra revealed that the strong positive relationships (r≥0.86, Ptrace elements as well as their scaling relationships can be characterized by single and joint multifractal parameters. The findings presented in this study could be extended to predict selected soil trace elements at larger regional scales with the aid of geographic information systems. PMID:23874944

  3. Evaluation of organic amendments on microbial soil respiration and agronomic variables in banana

    Directory of Open Access Journals (Sweden)

    Wuellins Dennis Durango Cabanilla

    2017-12-01

    Full Text Available The effect of the use of organic amendments on soil microbial respiration and agronomic variables in banana plants was studied, evaluating 22 treatments consisting of three amendments and four organic products, each in three doses and control treatmet (no amendment. The results showed significant increases in soil microbial respiration, with high doses of vinasse and mycorrhizae at 90 days after transplantation. In the agronomic variables were found significant differences of increase of height, diameter of pseudotallo and dry matter, with the amendments: vinaza, shrimp fluor, humus and biostimulant. Therefore, from the results obtained it can be concluded that the organic amendments increased the microbial respiration activity and stimulated the agronomic development of the banana plant.

  4. Comparing measured and modelled soil carbon: which site-specific variables are linked to high stability?

    Science.gov (United States)

    Robertson, Andy; Schipanski, Meagan; Ma, Liwang; Ahuja, Lajpat; McNamara, Niall; Smith, Pete; Davies, Christian

    2016-04-01

    Changes in soil carbon (C) stocks have been studied in depth over the last two decades, as net greenhouse gas (GHG) sinks are highlighted to be a partial solution to the causes of climate change. However, the stability of this soil C is often overlooked when measuring these changes. Ultimately a net sequestration in soils is far less beneficial if labile C is replacing more stable forms. To date there is no accepted framework for measuring soil C stability, and as a result there is considerable uncertainty associated with the simulated impacts of land management and land use change when using process-based systems models. However, a recent effort to equate measurable soil C fractions to model pools has generated data that help to assess the impacts of land management, and can ultimately help to reduce the uncertainty of model predictions. Our research compiles this existing fractionation data along with site metadata to create a simplistic statistical model able to quantify the relative importance of different site-specific conditions. Data was mined from 23 published studies and combined with original data to generate a dataset of 100+ land use change sites across Europe. For sites to be included they required soil C fractions isolated using the Zimmermann et al. (2007) method and specific site metadata (mean annual precipitation, MAP; mean annual temperature, MAT; soil pH; land use; altitude). Of the sites, 75% were used to develop a generalized linear mixed model (GLMM) to create coefficients where site parameters can be used to predict influence on the measured soil fraction C stocks. The remaining 25% of sites were used to evaluate uncertainty and validate this empirical model. Further, four of the aforementioned sites were used to simulate soil C dynamics using the RothC, DayCent and RZWQM2 models. A sensitivity analysis (4096 model runs for each variable applying Latin hypercube random sampling techniques) was then used to observe whether these models place

  5. Spatial variability and stocks of soil organic carbon in the Gobi desert of Northwestern China.

    Directory of Open Access Journals (Sweden)

    Pingping Zhang

    Full Text Available Soil organic carbon (SOC plays an important role in improving soil properties and the C global cycle. Limited attention, though, has been given to assessing the spatial patterns and stocks of SOC in desert ecosystems. In this study, we quantitatively evaluated the spatial variability of SOC and its influencing factors and estimated SOC storage in a region (40 km2 of the Gobi desert. SOC exhibited a log-normal depth distribution with means of 1.6, 1.5, 1.4, and 1.4 g kg(-1 for the 0-10, 10-20, 20-30, and 30-40 cm layers, respectively, and was moderately variable according to the coefficients of variation (37-42%. Variability of SOC increased as the sampling area expanded and could be well parameterized as a power function of the sampling area. Significant correlations were detected between SOC and soil physical properties, i.e. stone, sand, silt, and clay contents and soil bulk density. The relatively coarse fractions, i.e. sand, silt, and stone contents, had the largest effects on SOC variability. Experimental semivariograms of SOC were best fitted by exponential models. Nugget-to-sill ratios indicated a strong spatial dependence for SOC concentrations at all depths in the study area. The surface layer (0-10 cm had the largest spatial dependency compared with the other layers. The mapping revealed a decreasing trend of SOC concentrations from south to north across this region of the Gobi desert, with higher levels close to an oasis and lower levels surrounded by mountains and near the desert. SOC density to depths of 20 and 40 cm for this 40 km2 area was estimated at 0.42 and 0.68 kg C m(-2, respectively. This study provides an important contribution to understanding the role of the Gobi desert in the global carbon cycle.

  6. Local Versus Remote Contributions of Soil Moisture to Near-Surface Temperature Variability

    Science.gov (United States)

    Koster, R.; Schubert, S.; Wang, H.; Chang, Y.

    2018-01-01

    Soil moisture variations have a straightforward impact on overlying air temperatures, wetter soils can induce higher evaporative cooling of the soil and thus, locally, cooler temperatures overall. Not known, however, is the degree to which soil moisture variations can affect remote air temperatures through their impact on the atmospheric circulation. In this talk we describe a two-pronged analysis that addresses this question. In the first segment, an extensive ensemble of NASA/GSFC GEOS-5 atmospheric model simulations is analyzed statistically to isolate and quantify the contributions of various soil moisture states, both local and remote, to the variability of air temperature at a given local site. In the second segment, the relevance of the derived statistical relationships is evaluated by applying them to observations-based data. Results from the second segment suggest that the GEOS-5-based relationships do, at least to first order, hold in nature and thus may provide some skill to forecasts of air temperature at subseasonal time scales, at least in certain regions.

  7. Dimensioning the Irrigation Variables for Table Grape Vineyards in Litho-soils

    Directory of Open Access Journals (Sweden)

    Pasquale Campi

    2010-10-01

    Full Text Available The pedo-climatic and farm characteristics of Bari’s hinterland have allowed for the diffusion of prestigious table viticulture. The typical “tendone” vineyard structure is set up after managing the surface of the soil. The karstic nature of the region and the thermo-rainfall trend during the vegetative season impede the vineyard from producing adequately without irrigation. Given the importance of water contributions to table grapes, it is necessary to correctly measure the water variables for economic and environmental reasons. Farmers often irrigate according to “fixed” turns and volumes, against the rules of “good irrigation practice” which consider monitoring the water status of the soil or plant as a prerequisite of irrigation scheduling. During this experiment, two methods of irrigation management were compared: “fixed-turn” and “on demand”. For “on demand” irrigation, the irrigation volume is calculated on the basis of the soil water status (estimated according to the “water balance” method described in the “Paper n. 56 FAO” and the irrigation is scheduled on the basis of the experimental relationship between “pre-dawn” leaf water potential and the water available in the soil. For this comparison, data from a 2-year “on farm” experimentation, in an area typical of table grape cultivation in Southern Italy, have been used. The results obtained show that, in respect to the “fixed-turn” management, the “on demand” management allows for a 20% reduction in water volumes, without compromising production. The water balance method proved to be a promising criterion for irrigation scheduling in these shallow soils, rich in stones (litho-soils. This only held true when the depth of the soil layer explored by the root system was defined by the “equivalent depth” and not by the actual soil’s depth.

  8. Classification of Brazilian soils by using LIBS and variable selection in the wavelet domain.

    Science.gov (United States)

    Pontes, Márcio José Coelho; Cortez, Juliana; Galvão, Roberto Kawakami Harrop; Pasquini, Celio; Araújo, Mário César Ugulino; Coelho, Ricardo Marques; Chiba, Márcio Koiti; de Abreu, Mônica Ferreira; Madari, Beáta Emöke

    2009-05-29

    This paper proposes a novel analytical methodology for soil classification based on the use of laser-induced breakdown spectroscopy (LIBS) and chemometric techniques. In the proposed methodology, linear discriminant analysis (LDA) is employed to build a classification model on the basis of a reduced subset of spectral variables. For the purpose of variable selection, three techniques are considered, namely the successive projection algorithm (SPA), the genetic algorithm (GA), and a stepwise formulation (SW). The use of a data compression procedure in the wavelet domain is also proposed to reduce the computational workload involved in the variable selection process. The methodology is validated in a case study involving the classification of 149 Brazilian soil samples into three different orders (Argissolo, Latossolo and Nitossolo). For means of comparison, soft independent modelling of class analogy (SIMCA) models are also employed. The best discrimination of soil types was attained by SPA-LDA, which achieved an average classification rate of 90% in the validation set and 72% in cross-validation. Moreover, the proposed wavelet compression procedure was found to be of value by providing a 100-fold reduction in computational workload without significantly compromising the classification accuracy of the resulting models.

  9. Modeling impacts of human footprint and soil variability on the potential distribution of invasive plant species in different biomes

    Science.gov (United States)

    Wan, Ji-Zhong; Wang, Chun-Jing; Yu, Fei-Hai

    2017-11-01

    Human footprint and soil variability may be important in shaping the spread of invasive plant species (IPS). However, until now, there is little knowledge on how human footprint and soil variability affect the potential distribution of IPS in different biomes. We used Maxent modeling to project the potential distribution of 29 IPS with wide distributions and long introduction histories in China based on various combinations of climatic correlates, soil characteristics and human footprint. Then, we evaluated the relative importance of each type of environmental variables (climate, soil and human footprint) as well as the difference in range and similarity of the potential distribution of IPS between different biomes. Human footprint and soil variables contributed to the prediction of the potential distribution of IPS, and different types of biomes had varying responses and degrees of impacts from the tested variables. Human footprint and soil variability had the highest tendency to increase the potential distribution of IPS in Montane Grasslands and Shrublands. We propose to integrate the assessment in impacts of human footprint and soil variability on the potential distribution of IPS in different biomes into the prevention and control of plant invasion.

  10. Alaskan soil carbon stocks: spatial variability and dependence on environmental factors

    Directory of Open Access Journals (Sweden)

    U. Mishra

    2012-09-01

    Full Text Available The direction and magnitude of soil organic carbon (SOC changes in response to climate change depend on the spatial and vertical distributions of SOC. We estimated spatially resolved SOC stocks from surface to C horizon, distinguishing active-layer and permafrost-layer stocks, based on geospatial analysis of 472 soil profiles and spatially referenced environmental variables for Alaska. Total Alaska state-wide SOC stock was estimated to be 77 Pg, with 61% in the active-layer, 27% in permafrost, and 12% in non-permafrost soils. Prediction accuracy was highest for the active-layer as demonstrated by highest ratio of performance to deviation (1.5. Large spatial variability was predicted, with whole-profile, active-layer, and permafrost-layer stocks ranging from 1–296 kg C m−2, 2–166 kg m−2, and 0–232 kg m−2, respectively. Temperature and soil wetness were found to be primary controllers of whole-profile, active-layer, and permafrost-layer SOC stocks. Secondary controllers, in order of importance, were found to be land cover type, topographic attributes, and bedrock geology. The observed importance of soil wetness rather than precipitation on SOC stocks implies that the poor representation of high-latitude soil wetness in Earth system models may lead to large uncertainty in predicted SOC stocks under future climate change scenarios. Under strict caveats described in the text and assuming temperature changes from the A1B Intergovernmental Panel on Climate Change emissions scenario, our geospatial model indicates that the equilibrium average 2100 Alaska active-layer depth could deepen by 11 cm, resulting in a thawing of 13 Pg C currently in permafrost. The equilibrium SOC loss associated with this warming would be highest under continuous permafrost (31%, followed by discontinuous (28%, isolated (24.3%, and sporadic (23.6% permafrost areas. Our high-resolution mapping of soil carbon stock reveals the

  11. Small-scale spatial variability of soil microbial community composition and functional diversity in a mixed forest

    Science.gov (United States)

    Wang, Qiufeng; Tian, Jing; Yu, Guirui

    2014-05-01

    Patterns in the spatial distribution of organisms provide important information about mechanisms that regulate the diversity and complexity of soil ecosystems. Therefore, information on spatial distribution of microbial community composition and functional diversity is urgently necessary. The spatial variability on a 26×36 m plot and vertical distribution (0-10 cm and 10-20 cm) of soil microbial community composition and functional diversity were studied in a natural broad-leaved Korean pine (Pinus koraiensis) mixed forest soil in Changbai Mountain. The phospholipid fatty acid (PLFA) pattern was used to characterize the soil microbial community composition and was compared with the community substrate utilization pattern using Biolog. Bacterial biomass dominated and showed higher variability than fungal biomass at all scales examined. The microbial biomass decreased with soil depths increased and showed less variability in lower 10-20 cm soil layer. The Shannon-Weaver index value for microbial functional diversity showed higher variability in upper 0-10 cm than lower 10-20 cm soil layer. Carbohydrates, carboxylic acids, polymers and amino acids are the main carbon sources possessing higher utilization efficiency or utilization intensity. At the same time, the four carbon source types contributed to the differentiation of soil microbial communities. This study suggests the higher diversity and complexity for this mix forest ecosystem. To determine the driving factors that affect this spatial variability of microorganism is the next step for our study.

  12. Fine scale spatial variability of microbial pesticide degradation in soil: scales, controlling factors, and implications

    Directory of Open Access Journals (Sweden)

    Arnaud eDechesne

    2014-12-01

    Full Text Available Pesticide biodegradation is a soil microbial function of critical importance for modern agriculture and its environmental impact. While it was once assumed that this activity was homogeneously distributed at the field scale, mounting evidence indicates that this is rarely the case. Here, we critically examine the literature on spatial variability of pesticide biodegradation in agricultural soil. We discuss the motivations, methods, and main findings of the primary literature. We found significant diversity in the approaches used to describe and quantify spatial heterogeneity, which complicates inter-studies comparisons. However, it is clear that the presence and activity of pesticide degraders is often highly spatially variable with coefficients of variation often exceeding 50% and frequently displays nonrandom spatial patterns. A few controlling factors have tentatively been identified across pesticide classes: they include some soil characteristics (pH and some agricultural management practices (pesticide application, tillage, while other potential controlling factors have more conflicting effects depending on the site or the pesticide. Evidence demonstrating the importance of spatial heterogeneity on the fate of pesticides in soil has been difficult to obtain but modelling and experimental systems that do not include soil’s full complexity reveal that this heterogeneity must be considered to improve prediction of pesticide biodegradation rates or of leaching risks. Overall, studying the spatial heterogeneity of pesticide biodegradation is a relatively new field at the interface of agronomy, microbial ecology, and geosciences and a wealth of novel data is being collected from these different disciplinary perspectives. We make suggestions on possible avenues to take full advantage of these investigations for a better understanding and prediction of the fate of pesticides in soil.

  13. Extraction of energy by a variable mass plate from an explosive charge

    Energy Technology Data Exchange (ETDEWEB)

    Karmanova, T.I.; Loboiko, G.B.

    1987-07-01

    This paper shows how the motion of plates with variable and constant mass is different. An equation of motion of a body with variable mass is presented which takes into account the decrease in the velocity after the collision. The authors explain how the work performed by the explosion products on a plate with increasing mass does not equal the kinetic energy acquired by the plate in the absence of an external pressure, but that the presence of the pressure from the explosion products partially compensates the loss in the velocity on collision. As the plate moves and its mass increases, the relative fraction of uncompensated losses will increase, since the pressure decreases on expansion.

  14. Evaluating Genetic Variability of Sorghum Mutant Lines Tolerant to Acid Soil

    Directory of Open Access Journals (Sweden)

    W. Puspitasari

    2012-08-01

    Full Text Available High rainfall in some parts in Indonesia causes soil become acidic. The main constraint of acid soil is phosphor (P deficiency and aluminum (Al toxicity which decrease plant productivity. To overcome this problem, it is important to develop a crop variety tolerant to such conditions. Sorghum is probably one of the potential crops to meet that objective. Sorghum has been reported to have wide adaptability to various agro-ecology and can be used as food and animal feed. Unfortunately, sorghum is not Indonesian origin so its genetic variability is still low. From previous breeding works with induced mutation, some promising mutant lines have been developed. These mutant lines were included in the experiment carried out in Tenjo with soil condition was classified as acid soil with pH 4.8 and exchangeable-Al content 2.43 me/100 g. The objectives of this experiment were to study the magnitude of genetic variability of agronomy and grain quality characters in sorghum in order to facilitate the breeding improvement of the species. Plant materials used in this study were ten genotypes, including 6 mutant lines and 4 control varieties. The randomized block design with three replications was used in the experiment. The genetic variabilities of agronomic and grain quality characters existed among genotypes, such as plant height, number of leaves, stalk diameter, biomass weight, panicle length, grain yield per plant, 100 seed weight and tannin content in the grain. The broad sense heritabilities of agronomic characters were estimated ranging from medium to high. Grain yield showed significantly positive correlation with agronomic characters observed, but it was negatively correlated with protein content

  15. Evaluating Genetic Variability of Sorghum Mutant Lines Tolerant to Acid Soil

    Directory of Open Access Journals (Sweden)

    W. Puspitasari

    2012-12-01

    Full Text Available High rainfall in some parts in Indonesia causes soil become acidic. The main constraint of acid soil is phosphor (P deficiency and aluminum (Al toxicity which decrease plant productivity. To overcome this problem, it is important to develop a crop variety tolerant to such conditions. Sorghum is probably one of the potential crops to meet that objective. Sorghum has been reported to have wide adaptability to various agro-ecology and can be used as food and animal feed. Unfortunately, sorghum is not Indonesian origin so its genetic variability is still low. From previous breeding works with induced mutation, some promising mutant lines have been developed. These mutant lines were included in the experiment carried out in Tenjo with soil condition was classified as acid soil with pH 4.8 and exchangeable-Al content 2.43 me/100 g. The objectives of this experiment were to study the magnitude of genetic variability of agronomy and grain quality characters in sorghum in order to facilitate the breeding improvement of the species. Plant materials used in this study were ten genotypes, including 6 mutant lines and 4 control varieties. The randomized block design with three replications was used in the experiment. The genetic variabilities of agronomic and grain quality characters existed among genotypes, such as plant height, number of leaves, stalk diameter, biomass weight, panicle length, grain yield per plant, 100 seed weight and tannin content in the grain. The broad sense heritabilities of agronomic characters were estimated ranging from medium to high. Grain yield showed significantly positive correlation with agronomic characters observed, but it was negatively correlated with protein content

  16. Drivers of small scale variability in soil-atmosphere fluxes of CH4, N2O and CO2 in a forest soil

    Science.gov (United States)

    Maier, Martin; Nicolai, Clara; Wheeler, Denis; Lang, Friedeike; Paulus, Sinikka

    2016-04-01

    Soil-atmosphere fluxes of CH4, N2O and CO2 can vary on different spatial scales, on large scales between ecosystems but also within apparently homogenous sites. While CO2 and CH4 consumption is rather evenly distibuted in well aerated soils, the production of N2O and CH4 seems to occur at hot spots that can be associated with anoxic or suboxic conditions. Small-scale variability in soil properties is well-known from field soil assesment, affecting also soil aeration and thus theoretically, greenhouse gas fluxes. In many cases different plant species are associated with different soil conditions and vegetation mapping should therefor combined with soil mapping. Our research objective was explaining the small scale variability of greenhouse gas fluxes in an apparently homogeneous 50 years old Scots Pine stand in a former riparian flood plain.We combined greenhouse gas measurements and soil physical lab measurments with field soil assessment and vegetation mapping. Measurements were conducted with at 60 points at a plot of 30 X 30 m at the Hartheim monitoring site (SW Germany). For greenhouse gas measurements a non-steady state chamber system and laser analyser, and a photoacoustic analyser were used. Our study shows that the well aerated site was a substantial sink for atmospheric CH4 (-2.4 nmol/m² s) and also a for N2O (-0.4 nmol/m² s), but less pronounced, whereas CO2 production was a magnitude larger (2.6 μmol/m² s). The spatial variability of the CH4 consumption of the soils could be explained by the variability of the soil gas diffusivity (measured in situ + using soil cores). Deviations of this clear trend were only observed at points where decomposing woody debris was directly under the litter layer. Soil texture ranged from gravel, coarse sand, fine sand to pure silt, with coarser texture having higher soil gas diffusivity. Changes in texture were rather abrupt at some positions or gradual at other positions, and were well reflected in the vegetation

  17. Factors Influencing Spatial Variability in Nitrogen Processing in Nitrogen-Saturated Soils

    Directory of Open Access Journals (Sweden)

    Frank S. Gilliam

    2001-01-01

    Full Text Available Nitrogen (N saturation is an environmental concern for forests in the eastern U.S. Although several watersheds of the Fernow Experimental Forest (FEF, West Virginia exhibit symptoms of N saturation, many watersheds display a high degree of spatial variability in soil N processing. This study examined the effects of temperature on net N mineralization and nitrification in N-saturated soils from FEF, and how these effects varied between high N-processing vs. low N-processing soils collected from two watersheds, WS3 (fertilized with [NH4]2SO4 and WS4 (untreated control. Samples of forest floor material (O1 horizon and mineral soil (to a 5-cm depth were taken from three subplots within each of four plots that represented the extremes of highest and lowest rates of net N mineralization and nitrification (hereafter, high N and low N, respectively of untreated WS4 and N-treated WS3: control/low N, control/high N, N-treated/low N, N-treated/high N. Forest floor material was analyzed for carbon (C, lignin, and N. Subsamples of mineral soil were extracted immediately with 1 N KCl and analyzed for NH4+ and NO3- to determine preincubation levels. Extracts were also analyzed for Mg, Ca, Al, and pH. To test the hypothesis that the lack of net nitrification observed in field incubations on the untreated/low N plot was the result of absence of nitrifier populations, we characterized the bacterial community involved in N cycling by amplification of amoA genes. Remaining soil was incubated for 28 d at three temperatures (10, 20, and 30°C, followed by 1 NKCl extraction and analysis for NH4+ and NO3-. Net nitrification was essentially 100% of net N mineralization for all samples combined. Nitrification rates from lab incubations at all temperatures supported earlier observations based on field incubations. At 30°C, rates from N-treated/high N were three times those of N-treated/low N. Highest rates were found for untreated/high N (two times greater than those of

  18. Field scale variability of solute transport parameters and related soil properties

    Directory of Open Access Journals (Sweden)

    B. Lennartz

    1997-01-01

    Full Text Available The spatial variability of transport parameters has to be taken into account for a reliable assessment of solute behaviour in natural field soils. Two field sites were studied by collecting 24 and 36 small undisturbed soil columns at an uniform grid of 15 m spacing. Displacement experiments were conducted in these columns with bromide traced water under unsaturated steady state transport conditions. Measured breakthrough curves (BTCs were evaluated with the simple convective-dispersive equation (CDE. The solute mobility index (MI calculated as the ratio of measured to fitted pore water velocity and the dispersion coefficient (D were used to classify bromide breakthrough behaviour. Experimental BTCs were classified into two groups: type I curves expressed classical solute behaviour while type II curves were characterised by the occurrence of a bromide concentration maximum before 0.35 pore volumes of effluent (MI<0.35 resulting from preferential flow conditions. Six columns from site A and 8 from site B were identified as preferential. Frequency distributions of the transport parameters (MI and D of both sites were either extremely skewed or bimodal. Log-transformation did not lead to a normal distribution in any case. Contour maps of bromide mass flux at certain time steps indicated the clustering of preferential flow regions at both sites. Differences in the extent of preferential flow between sites seemed to be governed by soil structure. Linear cross correlations among transport parameters and independently measured soil properties revealed relations between solute mobility and volumetric soil water content at time of sampling, texture and organic carbon content. The volumetric field soil water content, a simple measure characterising the soil hydraulic behaviour at the sampling location, was found to be a highly sensitive parameter with respect to solute mobility and preferential flow situations. Almost no relation was found between solute

  19. A distributed Grid-Xinanjiang model with integration of subgrid variability of soil storage capacity

    Directory of Open Access Journals (Sweden)

    Wei-jian Guo

    2016-04-01

    Full Text Available Realistic hydrological response is sensitive to the spatial variability of landscape properties. For a grid-based distributed rainfall-runoff model with a hypothesis of a uniform grid, the high-frequency information within a grid cell will be gradually lost as the resolution of the digital elevation model (DEM grows coarser. Therefore, the performance of a hydrological model is usually scale-dependent. This study used the Grid-Xinanjiang (GXAJ model as an example to investigate the effects of subgrid variability on hydrological response at different scales. With the aim of producing a more reasonable hydrological response and spatial description of the landscape properties, a new distributed rainfall-runoff model integrating the subgrid variability (the GXAJSV model was developed. In this model, the topographic index is used as an auxiliary variable correlated with the soil storage capacity. The incomplete beta distribution is suggested for simulating the probability distribution of the soil storage capacity within the raster grid. The Yaogu Basin in China was selected for model calibration and validation at different spatial scales. Results demonstrated that the proposed model can effectively eliminate the scale dependence of the GXAJ model and produce a more reasonable hydrological response.

  20. Life Comparison of kinematic variables of gait on a treadmill and on soil of individuals with Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Késia Maísa Amaral-Felipe

    2017-11-01

    Full Text Available The treadmill has been used for gait analysis in many studies, however, it is necessary to check whether the treadmill gait can reproduce similarly to gait on soil. The aim of this study was to compare gait kinematic variables on a treadmill and on soil in patients with Parkinson's disease. The sample consisted of seven individuals of both genders, diagnosed with idiopathic Parkinsonism who performed independent walking. Gait biomechanical analysis on soil with preferred speed for five consecutive times was performed. Participants walked on a circuit to ensure continuous walk. Gait analysis on the treadmill was realized for 30 minutes after familiarization protocol. No significant differences were found on the variables between gait on soil and on the treadmill of the participants. The gait in soil is similar, in relation to the kinematic variables analyzed, to the treadmill gait after familiarization period.

  1. Regional scale spatio-temporal variability of soil moisture and its relationship with meteorological factors over the Korean peninsula

    Science.gov (United States)

    Cho, Eunsang; Choi, Minha

    2014-08-01

    An understanding soil moisture spatio-temporal variability is essential for hydrological and meteorological research. This work aims at evaluating the spatio-temporal variability of near surface soil moisture and assessing dominant meteorological factors that influence spatial variability over the Korean peninsula from May 1 to September 29, 2011. The results of Kolmogorov-Smirnov tests for goodness of fit showed that all applied distributions (normal, log-normal and generalized extreme value: GEV) were appropriate for the datasets and the GEV distribution described best spatial soil moisture patterns. The relationship between the standard deviation and coefficient of variation (CV) of soil moisture with mean soil moisture contents showed an upper convex shape and an exponentially negative pattern, respectively. Skewness exhibited a decreasing pattern with increasing mean soil moisture contents and kurtosis exhibited the U-shaped relationship. In this regional scale (99,720 km2), we found that precipitation indicated temporally stable features through an ANOVA test considering the meteorological (i.e. precipitation, insolation, air temperature, ground temperature and wind speed) and physical (i.e. soil texture, elevation, topography, and land use) factors. Spatial variability of soil moisture affected by the meteorological forcing is shown as result of the relationship between the meteorological factors (precipitation, insolation, air temperature and ground temperature) and the standard deviation of relative difference of soil moisture contents (SDRDt) which implied the spatial variability of soil moisture. The SDRDt showed a positive relationship with the daily mean precipitation, while a negative relationship with insolation, air temperature and ground temperature. The variation of spatial soil moisture pattern is more sensitive to change in ground temperature rather than air temperature changes. Therefore, spatial variability of soil moisture is greatly affected

  2. Mercury in urban soils: A comparison of local spatial variability in six European cities

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, S. [Departamento de Quimica, Universidade de Aveiro 3810-193 Aveiro (Portugal)]. E-mail: smorais@dq.ua.pt; Pereira, M.E. [Departamento de Quimica, Universidade de Aveiro 3810-193 Aveiro (Portugal); Duarte, A.C. [Departamento de Quimica, Universidade de Aveiro 3810-193 Aveiro (Portugal); Ajmone-Marsan, F. [DI.VA.P.R.A., Chimica Agraria, Universita di Torino, Via Leonardo da Vinci, 44 10095 Grugliasco, Torino (Italy); Davidson, C.M. [Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral St, Glasgow G1 1XL, Scotland (United Kingdom); Grcman, H. [Univerza v Ljubljani, Biotehniska fakulteta, 1000 Ljubljana (Slovenia); Hossack, I. [School of Engineering and Science, University of Paisley, High Street, Paisley, PA1 2BE Scotland (United Kingdom); Hursthouse, A.S. [School of Engineering and Science, University of Paisley, High Street, Paisley, PA1 2BE Scotland (United Kingdom); Ljung, K. [Swedish University of Agricultural Sciences, Department of Soil Sciences, P.O. Box 7014, SE-750 07 Uppsala (Sweden); Martini, C. [DI.VA.P.R.A., Chimica Agraria, Universita di Torino, Via Leonardo da Vinci, 44 10095 Grugliasco, Torino (Italy); Otabbong, E. [Swedish University of Agricultural Sciences, Department of Soil Sciences, P.O. Box 7014, SE-750 07 Uppsala (Sweden); Reinoso, R. [Instituto de Recursos Naturales y Agrobiologia de Sevilla (CSIC), Apartado 1052, 41080 Sevilla (Spain); Ruiz-Cortes, E. [Instituto de Recursos Naturales y Agrobiologia de Sevilla (CSIC), Apartado 1052, 41080 Sevilla (Spain); Urquhart, G.J. [Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral St, Glasgow G1 1XL, Scotland (United Kingdom); Vrscaj, B. [Univerza v Ljubljani, Biotehniska fakulteta, 1000 Ljubljana (Slovenia)

    2006-09-15

    The objective of this study was to quantify and assess for the first time the variability of total mercury in urban soils at a European level, using a systematic sampling strategy and a common methodology. We report results from a comparison between soil samples from Aveiro (Portugal), Glasgow (Scotland), Ljubljana (Slovenia), Sevilla (Spain), Torino (Italy) and Uppsala (Sweden). At least 25 sampling points (in about 4-5 ha) from a park in each city were sampled at two depths (0-10 and 10-20 cm). Total mercury was determined by pyrolysis atomic absorption spectrometry with gold amalgamation. The quality of results was monitored using certified reference materials (BCR 142R and BCR 141R). Measured total mercury contents varied from 0.015 to 6.3 mg kg{sup -1}. The lowest median values were found in Aveiro, for both surface (0-10 cm) and sub-surface (10-20 cm) samples (0.055 and 0.054 mg kg{sup -1}, respectively). The highest median mercury contents in soil samples were found in samples from Glasgow (1.2 and 1.3 mg kg{sup -1}, for surface and sub-surface samples, respectively). High variability of mercury concentrations was observed, both within each park and between cities. This variability reflecting contributions from natural background, previous anthropogenic activities and differences in the ages of cities and land use, local environmental conditions as well as the influence of their location within the urban area. Short-range variability of mercury concentrations was found to be up to an order of magnitude over the distance of only a few 10 m.

  3. Diurnal spatial variability of soil respiration estimated by ordinary kriging and sequential Gaussian simulation

    Science.gov (United States)

    de Bortoli Teixeira, Daniel; Rodrigo Panosso, Alan; Tadeu Pereira, Gener; Pelegrino Cerri, Carlos Eduardo; La Scala, Newton, Jr.

    2010-05-01

    The role of greenhouse gases in the climate change is well know, however, the balance of greenhouse gases due to land use and management is still lacking. Hence it is important to characterize the main aspects of soil respiration (or soil CO2 emission) in agricultural areas, including its spatial variability, as quantitatively as possible. The objective of this work was to study the diurnal spatial variability of the soil respiration including their estimations by different methods: ordinary kriging and sequential Gaussian simulation. Evaluations were conducted in a regular grid having 64 points installed over a bare Eutrustox clay texture during the morning and afternoon periods. Measurements were conducted from 7:30 - 10:30 am (morning) and 13:30 - 16:30 pm (afternoon) using a portable soil respiration system (LI-8100), Lincoln, NE, USA. In order to estimate the best interpolation method it was applied the so-called external validation, where the respiration values of 5 points in grid were removed from interpolation process and after were estimated in the same points by kriging or sequential Gaussian simulation methods. This evaluation was also based on the sum of the square of residues, comparing observed with predicted respiration values in each of the 5 points selected for external validation. The highest CO2 emission was observed in the afternoon period, with mean value of 6.24 µmol m-2 s-1, when compared to the morning (4.54 µmol m-2 s-1). Our results indicate that the measurement period (morning or afternoon) did not interfere into the definition of emission spatial variability structure, as coefficient of variation, spatial variability models and their parameters were quite similar in morning and afternoon. However, despite the high correlation between kriging and sequential Gaussian simulation respiration maps (R2 =0.99) sequential Gaussian simulation showed to be more efficient into the estimations of non-sampled emissions in both periods, mornings and

  4. Landscape structure control on soil CO2 efflux variability in complex terrain: Scaling from point observations to watershed scale fluxes

    Science.gov (United States)

    Diego A. Riveros-Iregui; Brian L. McGlynn

    2009-01-01

    We investigated the spatial and temporal variability of soil CO2 efflux across 62 sites of a 393-ha complex watershed of the northern Rocky Mountains. Growing season (83 day) cumulative soil CO2 efflux varied from ~300 to ~2000 g CO2 m-2, depending upon landscape position, with a median of 879.8 g CO2 m-2. Our findings revealed that highest soil CO2 efflux rates were...

  5. Maxwell's Law Based Models for Liquid and Gas Phase Diffusivities in Variably-Saturated Soil

    DEFF Research Database (Denmark)

    Mamamoto, Shoichiro; Møldrup, Per; Kawamoto, Ken

    2012-01-01

    The gas diffusion coefficient (D-s,D-g) and solute diffusion coefficient (D-s,D-l) and their dependencies on fluid content (kappa) (equal to soil-air content theta for D-s,D-g and soil-water content epsilon for D-s,D-l) are controlling factors for gas and solute transport in variably saturated...... soils. In this study, we propose unified, predictive models for D-s,D-g(epsilon) and D-s,D-l(theta) based on modifying and extending the classical Maxwell model at fluid saturation with a fluid-induced reduction term including a percolation threshold (epsilon(th) for D-s,D-g and theta(th) for D......-s,D-l). Different percolation threshold terms adopted from recent studies for gas (D-s,D-g) and solute (D-s,D-l) diffusion were applied. For gas diffusion, epsilon(th) was a function of bulk density (total porosity), while for solute diffusion theta(th) was best described by volumetric content of finer soil...

  6. Spatial variability and hotspots of soil N2O fluxes from intensively grazed grassland

    Science.gov (United States)

    Cowan, N. J.; Norman, P.; Famulari, D.; Levy, P. E.; Reay, D. S.; Skiba, U. M.

    2015-03-01

    One hundred N2O flux measurements were made from an area of intensively managed grazed grassland in central Scotland using a high-resolution dynamic chamber method. The field contained a variety of features from which N2O fluxes were measured including a manure heap, patches of decaying grass silage, and areas of increased sheep activity. Individual fluxes varied significantly across the field varying from 2 to 79 000 μg N2O-N m-2 h-1. Soil samples were collected at 55 locations to investigate relationships between soil properties and N2O flux. Fluxes of N2O correlated strongly with soil NO3- concentrations. Distribution of NO3- and the high spatial variability of N2O flux across the field are shown to be linked to the distribution of waste from grazing animals and the resultant reactive nitrogen compounds in the soil which are made available for microbiological processes. Features within the field such as shaded areas and manure heaps contained significantly higher available nitrogen than the rest of the field. Although these features only represented 1.1% of the area of the field, they contributed to over 55% of the total estimated daily N2O flux.

  7. Space-time soil moisture variability for two different land use types: analysis at the plot scale

    Science.gov (United States)

    Zuecco, Giulia; Borga, Marco; Penna, Daniele; Canone, Davide; Ferraris, Stefano

    2013-04-01

    Understanding space-time soil moisture variability at various scales is a key issue in hydrological research. At the plot scale soil moisture variability is expected to be explained by physical factors such as soil hydraulic properties, local topography and vegetation cover. This study aims to: i) characterize the spatial and temporal variability of soil moisture at the plot scale at two soil depths and for two different types of land use (meadow and vineyard); ii) investigate the role of vegetation cover on the seasonal variability of soil moisture; iii) assess the capability of a dynamic model to explain soil moisture variability and the control exerted by land use. The work is based on soil moisture data collected on a plot (about 200 m2) in Grugliasco (Po River basin, Northern Italy) by means of Time Domain Reflectometry (TDR) measurements. The plot is divided into two subplots: one covered by grapevine plants, the other covered homogeneously by grass. The soil is sandy, the slope is about 1%, and there is a buffer grass area about 20 m wide around the measurement field. The characteristics of the site allow to isolate the contribution of soil hydraulic properties and land use to space-time soil moisture variability. We used the data of 40 probes distributed in the two subplots, vertically inserted into the soil at 0-30 cm and 0-60 cm depths. Precipitation and temperature are recorded continuously on site. Statistics were computed based on soil moisture measurements collected continuously at daily time step over three years (2006-2008). Results show that soil moisture spatial patterns at the two sampling depths are highly correlated for both land uses. Higher values of mean soil moisture at 0-60 cm depth with respect to 0-30 cm for both types of land use likely reflect the evaporation processes affecting more the surface layer. Spatial mean soil moisture is always higher in the vineyard than in the meadow (especially at 0-30 cm depth), implying the influence of

  8. Analysis of national pay-as-you-drive insurance systems and other variable driving charges

    Energy Technology Data Exchange (ETDEWEB)

    Wenzel, T.

    1995-07-01

    Under Pay as You Drive insurance (PAYD), drivers would pay part of their automobile insurance premium as a per-gallon surcharge every time they filled their gas tank. By transfering a portion of the cost of owning a vehicle from a fixed cost to a variable cost, PAYD would discourage driving. PAYD has been proposed recently in California as a means of reforming how auto insurance is provided. PAYD proponents claim that, by forcing drivers to purchase at least part of their insurance every time they refuel their car, PAYD would reduce or eliminate the need for uninsured motorist coverage. Some versions of PAYD proposed in California have been combined with a no-fault insurance system, with the intention of further reducing premiums for the average driver. Other states have proposed PAYD systems that would base insurance premiums on annual miles driven. In this report we discuss some of the qualitative issues surrounding adoption of PAYD and other policies that would convert other fixed costs of driving (vehicle registration, safety/emission control system inspection, and driver license renewal) to variable costs. We examine the effects of these policies on two sets of objectives: objectives related to auto insurance reform, and those related to reducing fuel consumption, CO{sub 2} emissions, and vehicle miles traveled. We pay particular attention to the first objective, insurance reform, since this has generated the most interest in PAYD to date, at least at the state level.

  9. Interannual Variability in Global Soil Respiration on a 0.5 Degree Grid Cell Basis (1980-1994)

    Energy Technology Data Exchange (ETDEWEB)

    Raich, J.W.

    2003-09-15

    We used a climate-driven regression model to develop spatially resolved estimates of soil-CO{sub 2} emissions from the terrestrial land surface for each month from January 1980 to December 1994, to evaluate the effects of interannual variations in climate on global soil-to-atmosphere CO{sub 2} fluxes. The mean annual global soil-CO{sub 2} flux over this 15-y period was estimated to be 80.4 (range 79.3-81.8) Pg C. Monthly variations in global soil-CO{sub 2} emissions followed closely the mean temperature cycle of the Northern Hemisphere. Globally, soil-CO{sub 2} emissions reached their minima in February and peaked in July and August. Tropical and subtropical evergreen broad-leaved forests contributed more soil-derived CO{sub 2} to the atmosphere than did any other vegetation type ({approx}30% of the total) and exhibited a biannual cycle in their emissions. Soil-CO{sub 2} emissions in other biomes exhibited a single annual cycle that paralleled the seasonal temperature cycle. Interannual variability in estimated global soil-CO{sub 2} production is substantially less than is variability in net carbon uptake by plants (i.e., net primary productivity). Thus, soils appear to buffer atmospheric CO{sub 2} concentrations against far more dramatic seasonal and interannual differences in plant growth. Within seasonally dry biomes (savannas, bushlands, and deserts), interannual variability in soil-CO{sub 2} emissions correlated significantly with interannual differences in precipitation. At the global scale, however, annual soil-CO{sub 2} fluxes correlated with mean annual temperature, with a slope of 3.3 PgCY{sup -1} per degree Celsius. Although the distribution of precipitation influences seasonal and spatial patterns of soil-CO{sub 2} emissions, global warming is likely to stimulate CO{sub 2} emissions from soils.

  10. Interannual variability of plant phenology in tussock tundra: modelling interactions of plant productivity, plant phenology, snowmelt and soil thaw

    NARCIS (Netherlands)

    Wijk, van M.T.; Williams, M.; Laundre, J.A.; Shaver, G.R.

    2003-01-01

    We present a linked model of plant productivity, plant phenology, snowmelt and soil thaw in order to estimate interannual variability of arctic plant phenology and its effects on plant productivity. The model is tested using 8 years of soil temperature data, and three years of bud break data of

  11. Soil salinity and acidity : spatial variabil[it]y and effects on rice production in West Africa's mangrove zone

    NARCIS (Netherlands)

    Sylla, M.

    1994-01-01

    In the mangrove environment of West Africa, high spatial and temporal variability of soil constraints (salinity and acidity) to rice production is a problem for the transfer and adoption of new agronomic techniques, for land use planning, and for soil and water management. Recently, several

  12. The effect of Cs-137 short-range spatial variability on soil after the Chernobyl disaster

    Science.gov (United States)

    Martynenko, Vladimir; Vakulovsky, Sergey; Linnik, Vitaly

    2014-05-01

    After the Chernobyl accident of 1986, large areas of Russia were contaminated by 137Cs. Post-depositional redistribution of 137Cs fallout across the land surface resulting from mechanical, physical, chemical, and biological processes operating in the soil system and the grain size selectivity associated with soil erosion and sediment transport processes. Therefore of uppermost importance are data on evaluating 137Cs variability at short distances, obtained at the early period after the accident. Measurements of 137Cs deposit at the territory of Russia exposed to radioactive contamination were mainly conducted with the help of air-gamma survey, and were verified by soil sampling on test plots with size 10x10 m with control soil sampling using "envelope" method of fivefold soil sampling (1 sampling at the centre and 4 along the edges of the plot under study). Presented here are evaluation data of 137Cs contamination, obtained in the Bryansk, Yaroslav and Rostov regions in 1991. Test plots were selected at the distance of 50-100 m away from a road on matted areas with undisturbed soil structure. Test routes of sampling were made perpendicularly to directions crossing basic traces of radioactive contamination. Sampling measurements were carried out at Canberra and Ortec gamma spectrometers. Each of the 5 samples of the "envelope" was measured separately, soil mixing was not applied. 137Cs value for the Bryansk Region varied from 2,6 kBq/m2 to 2294 kBq/m2, at the territories of the Yaroslav and Rostov regions 137Cs value varied from 0,44 kBq/m2 to 5,1 kBq/m2 and 0,56 kBq/m2 to 22,2 kBq/m2, respectively. Statistical analysis of 137Cs deposit at different plots is a solid argumentation in favour of nonuniform distribution in various landscapes and at a different distance from the Chernobyl NPP. Such nonuniformity of 137Cs soil contamination in the limits of 10 m of the plot is most likely to be related to initial aerosol contamination nonuniformity at the moment of

  13. 17 CFR 274.303 - Form N-27I-2, notice of withdrawal right and statement of charges for variable life insurance...

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Form N-27I-2, notice of withdrawal right and statement of charges for variable life insurance contractholders required pursuant to... variable life insurance contractholders required pursuant to Rule 6e-2 (§ 270.6e-2 of this chapter...

  14. Drivers of Plot-Scale Variability of CH4 Consumption in a Well-Aerated Pine Forest Soil

    Directory of Open Access Journals (Sweden)

    Martin Maier

    2017-06-01

    Full Text Available While differences in greenhouse gas (GHG fluxes between ecosystems can be explained to a certain degree, variability of the same at the plot scale is still challenging. We investigated the spatial variability in soil-atmosphere fluxes of carbon dioxide (CO2, methane (CH4 and nitrous oxide (N2O to find out what drives spatial variability on the plot scale. Measurements were carried out in a Scots pine (Pinus sylvestris L. forest in a former floodplain on a 250 m2 plot, divided in homogenous strata of vegetation and soil texture. Soil gas fluxes were measured consecutively at 60 points along transects to cover the spatial variability. One permanent chamber was measured repeatedly to monitor temporal changes to soil gas fluxes. The observed patterns at this control chamber were used to standardize the gas fluxes to disentangle temporal variability from the spatial variability of measured GHG fluxes. Concurrent measurements of soil gas diffusivity allowed deriving in situ methanotrophic activity from the CH4 flux measurements. The soil emitted CO2 and consumed CH4 and N2O. Significantly different fluxes of CH4 and CO2 were found for the different soil-vegetation strata, but not for N2O. Soil CH4 consumption increased with soil gas diffusivity within similar strata supporting the hypothesis that CH4 consumption by soils is limited by the supply with atmospheric CH4. Methane consumption in the vegetation strata with dominant silty texture was higher at a given soil gas diffusivity than in the strata with sandy texture. The same pattern was observed for methanotrophic activity, indicating better habitats for methantrophs in silt. Methane consumption increased with soil respiration in all strata. Similarly, methanotrophic activity increased with soil respiration when the individual measurement locations were categorized into silt and sand based on the dominant soil texture, irrespective of the vegetation stratum. Thus, we suggest the rhizosphere and

  15. Changes in canopy structure and ant assemblages affect soil ecosystem variables as a foundation species declines

    DEFF Research Database (Denmark)

    Kendrick, Joseph A.; Ribbons, Relena Rose; Classen, Aimee Taylor

    2015-01-01

    , we built ant exclosure subplots within all of the canopy manipulation plots to examine direct and interactive effects of canopy change and ant assemblage composition on soil and litter variables. Throughout HF-HeRE, T. canadensis was colonized by the adelgid in 2009, and the infested trees are now...... declining. The experimental removal of T. canadensis from the canopy was associated with an increase in the rate of cellulose decomposition by >50%, and exclosure of ants from subplots directly reduced their soil nitrate availability by 56%. Partial least squares path models revealed sequential interactive...... effects prior to adelgid infestation: canopy change (as a proxy for associated environmental changes) altered both decomposition and ant assemblage structure; changes in ant assemblage structure and decomposition rates altered nitrogen availability. The results illustrate that biotic changes directly...

  16. Simulating maize yield and bomass with spatial variability of soil field capacity

    Science.gov (United States)

    Ma, Liwang; Ahuja, Lajpat; Trout, Thomas; Nolan, Bernard T.; Malone, Robert W.

    2015-01-01

    Spatial variability in field soil properties is a challenge for system modelers who use single representative values, such as means, for model inputs, rather than their distributions. In this study, the root zone water quality model (RZWQM2) was first calibrated for 4 yr of maize (Zea mays L.) data at six irrigation levels in northern Colorado and then used to study spatial variability of soil field capacity (FC) estimated in 96 plots on maize yield and biomass. The best results were obtained when the crop parameters were fitted along with FCs, with a root mean squared error (RMSE) of 354 kg ha–1 for yield and 1202 kg ha–1 for biomass. When running the model using each of the 96 sets of field-estimated FC values, instead of calibrating FCs, the average simulated yield and biomass from the 96 runs were close to measured values with a RMSE of 376 kg ha–1 for yield and 1504 kg ha–1 for biomass. When an average of the 96 FC values for each soil layer was used, simulated yield and biomass were also acceptable with a RMSE of 438 kg ha–1 for yield and 1627 kg ha–1 for biomass. Therefore, when there are large numbers of FC measurements, an average value might be sufficient for model inputs. However, when the ranges of FC measurements were known for each soil layer, a sampled distribution of FCs using the Latin hypercube sampling (LHS) might be used for model inputs.

  17. Probing Quantum Chromodynamics with the ATLAS Detector: Charged-Particle Event Shape Variables and the Dijet Cross-Section

    CERN Document Server

    Hülsing, Tobias

    Quantum chromodynamics, QCD, the theory of the strong interaction is split into two regimes. Scattering processes of the proton constituents, the partons, with a high momentum transfer $Q^2$ can be calculated and predicted with perturbative calculations. At low momentum transfers between the scattering particles perturbation theory is not applicable anymore, and phenomenological methods are used to describe the physics in this regime. The ATLAS experiment at the Large Hadron Collider, LHC, provides the possibility to analyze QCD processes at both ends of the momentum scale. Two measurements are presented in this thesis, emphasizing one of the two regimes each: The measurement of charged-particle event shape variables in inelastic proton–proton collisions at a center-of-mass energy of $\\sqrt{s}$ = 7 TeV analyses the transverse momentum flow and structure of hadronic events. Due to the, on average, low momentum transfer, predictions of these events are mainly driven by non-perturbative models. Three event sha...

  18. Fine-Scale Spatial Variability of Precipitation, Soil, and Plant Water Isotopes

    Science.gov (United States)

    Goldsmith, G. R.; Braun, S.; Romero, C.; Engbersen, N.; Gessler, A.; Siegwolf, R. T.; Schmid, L.

    2015-12-01

    Introduction: The measurement of stable isotope ratios of water has become fundamental in advancing our understanding of environmental patterns and processes, particularly with respect to understanding the movement of water within the soil-plant-atmosphere continuum. While considerable research has explored the temporal variation in stable isotope ratios of water in the environment, our understanding of the spatial variability of these isotopes remains poorly understood. Methods: We collected spatially explicit samples of throughfall and soil water (n=150 locations) from a 1 ha plot delineated in a mixed deciduous forest in the northern Alps of Switzerland. We complemented this with fully sunlit branch and leaf samples (n = 60 individuals) collected from Picea abies and Fagus sylvatica between 14:00 and 16:00 on the same day by means of a helicopter. Soil and plant waters were extracted using cryogenic vacuum distillation and all samples were analyzed for δ18O using an isotope ratio mass spectrometer. Results: The mean δ18O of throughfall (-3.3 ± 0.8‰) indicated some evaporative enrichment associated with passage through the canopy, but this did not significantly differ from the precipitation collected in nearby open sites (-4.05‰). However, soil was depleted (-7.0 ± 1.8‰) compared to throughfall and there was no significant relationship between the two, suggesting that the sampling for precipitation inputs did not capture all the sources (e.g. stream water, which was -11.5‰) contributing to soil water δ18O ratios. Evaporative enrichment of δ18O was higher in leaves of Fagus (14.8 ± 1.8‰) than in leaves of Picea (11.8 ± 1.7‰). Sampling within crowns of each species (n = 5 branches each from 5 individuals) indicated that variability in a single individual is similar to that among individuals. Discussion: Stable isotopes of water are frequently engaged for studies of ecohydrology, plant ecophysiology, and paleoclimatology. Our results help

  19. Soil water and transpirable soil water fraction variability within vineyards of the Penedès DO (NE Spain) affected by management practices

    Science.gov (United States)

    Concepción Ramos, Maria

    2015-04-01

    This work investigated the variability in soil water recorded within the vineyard plots related to soil properties and management practices and its influence on the transpirable sol water fraction. The study was carried out in vineyards in the Penedès Designation of Origin, planted with Chardonnay, with different disturbance degree and with compost treated and untreated areas within the plots. The response in years with different rainfall distributions, included years with extreme situations were evaluated. The main soil types are Typic Xerorthent and Calcixerollic Xerorthent and soil is bare most of the time. Soil water content was measured at different depths using TDR probes. The transpirable soil water fraction was estimated as the ratio between available soil water (ASW) at a given date and the total transpirable soil water (TTSW). TTSW was estimated as the soil water reserve held between an upper and lower limit (respectively, the soil water content near field capacity and soil water content at the end of a dry summer) and integrated over the estimated effective rooting depth. Both minimum and maximum soil water values varied within the plot at all depths. On the surface the minimum values ranged between 4.45 to about 10%, while on deeper layers it ranged between 7.8 and 17.8%. Regarding the maximum value varied between 17.45 and 24.8%. The transpirable soil water fraction for a given year varied significantly within the plot, with differences greater than 20% between the treated and untreated areas. The results were more exacerbated in the driest years an in those with more irregular distribution. Water available has a significant effect on yield. The results indicate the need of using different strategies for water management within the plots.

  20. Measurement of charged-particle event shape variables in $\\sqrt{s}$ = 7 TeV proton-proton interactions with the ATLAS detector

    CERN Document Server

    Aad, Georges; Abbott, Brad; Abdallah, Jalal; Abdel Khalek, Samah; Abdelalim, Ahmed Ali; Abdinov, Ovsat; Aben, Rosemarie; Abi, Babak; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Acerbi, Emilio; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Addy, Tetteh; Adelman, Jahred; Adomeit, Stefanie; Adragna, Paolo; Adye, Tim; Aefsky, Scott; Aguilar-Saavedra, Juan Antonio; Agustoni, Marco; Aharrouche, Mohamed; Ahlen, Steven; Ahles, Florian; Ahmad, Ashfaq; Ahsan, Mahsana; Aielli, Giulio; Akdogan, Taylan; Åkesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Alam, Mohammad; Alam, Muhammad Aftab; Albert, Justin; Albrand, Solveig; Aleksa, Martin; Aleksandrov, Igor; Alessandria, Franco; Alexa, Calin; Alexander, Gideon; Alexandre, Gauthier; Alexopoulos, Theodoros; Alhroob, Muhammad; Aliev, Malik; Alimonti, Gianluca; Alison, John; Allbrooke, Benedict; Allport, Phillip; Allwood-Spiers, Sarah; Almond, John; Aloisio, Alberto; Alon, Raz; Alonso, Alejandro; Alonso, Francisco; Alvarez Gonzalez, Barbara; Alviggi, Mariagrazia; Amako, Katsuya; Amelung, Christoph; Ammosov, Vladimir; Amorim, Antonio; Amram, Nir; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Anduaga, Xabier; Anger, Philipp; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antonaki, Ariadni; Antonelli, Mario; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoki, Masato; Aoun, Sahar; Aperio Bella, Ludovica; Apolle, Rudi; Arabidze, Giorgi; Aracena, Ignacio; Arai, Yasuo; Arce, Ayana; Arfaoui, Samir; Arguin, Jean-Francois; Arik, Engin; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnal, Vanessa; Arnault, Christian; Artamonov, Andrei; Artoni, Giacomo; Arutinov, David; Asai, Shoji; Asfandiyarov, Ruslan; Ask, Stefan; Åsman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astbury, Alan; Atkinson, Markus; Aubert, Bernard; Auge, Etienne; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Avramidou, Rachel Maria; Axen, David; Azuelos, Georges; Azuma, Yuya; Baak, Max; Baccaglioni, Giuseppe; Bacci, Cesare; Bach, Andre; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Badescu, Elisabeta; Bagnaia, Paolo; Bahinipati, Seema; Bai, Yu; Bailey, David; Bain, Travis; Baines, John; Baker, Oliver Keith; Baker, Mark; Baker, Sarah; Banas, Elzbieta; Banerjee, Piyali; Banerjee, Swagato; Banfi, Danilo; Bangert, Andrea Michelle; Bansal, Vikas; Bansil, Hardeep Singh; Barak, Liron; Baranov, Sergei; Barbaro Galtieri, Angela; Barber, Tom; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Bardin, Dmitri; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnett, Bruce; Barnett, Michael; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Barrillon, Pierre; Bartoldus, Rainer; Barton, Adam Edward; Bartsch, Valeria; Basye, Austin; Bates, Richard; Batkova, Lucia; Batley, Richard; Battaglia, Andreas; Battistin, Michele; Bauer, Florian; Bawa, Harinder Singh; Beale, Steven; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Becker, Anne Kathrin; Becker, Sebastian; Beckingham, Matthew; Becks, Karl-Heinz; Beddall, Andrew; Beddall, Ayda; Bedikian, Sourpouhi; Bednyakov, Vadim; Bee, Christopher; Beemster, Lars; Begel, Michael; Behar Harpaz, Silvia; Beimforde, Michael; Belanger-Champagne, Camille; Bell, Paul; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellina, Francesco; Bellomo, Massimiliano; Belloni, Alberto; Beloborodova, Olga; Belotskiy, Konstantin; Beltramello, Olga; Benary, Odette; Benchekroun, Driss; Bendtz, Katarina; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez Garcia, Jorge-Armando; Benjamin, Douglas; Benoit, Mathieu; Bensinger, James; Benslama, Kamal; Bentvelsen, Stan; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Berglund, Elina; Beringer, Jürg; Bernat, Pauline; Bernhard, Ralf; Bernius, Catrin; Berry, Tracey; Bertella, Claudia; Bertin, Antonio; Bertolucci, Federico; Besana, Maria Ilaria; Besjes, Geert-Jan; Besson, Nathalie; Bethke, Siegfried; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianco, Michele; Biebel, Otmar; Bieniek, Stephen Paul; Bierwagen, Katharina; Biesiada, Jed; Biglietti, Michela; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien; Bingul, Ahmet; Bini, Cesare; Biscarat, Catherine; Black, Kevin; Blair, Robert; Blanchard, Jean-Baptiste; Blanchot, Georges; Blazek, Tomas; Blocker, Craig; Blocki, Jacek; Blondel, Alain; Blum, Walter; Blumenschein, Ulrike; Bobbink, Gerjan; Bobrovnikov, Victor; Bocchetta, Simona Serena; Bocci, Andrea; Boddy, Christopher Richard; Boehler, Michael; Boek, Jennifer; Boelaert, Nele; Bogaerts, Joannes Andreas; Bogdanchikov, Alexander; Bogouch, Andrei; Bohm, Christian; Bohm, Jan; Boisvert, Veronique; Bold, Tomasz; Boldea, Venera; Bolnet, Nayanka Myriam; Bomben, Marco; Bona, Marcella; Boonekamp, Maarten; Booth, Chris; Bordoni, Stefania; Borer, Claudia; Borisov, Anatoly; Borissov, Guennadi; Borjanovic, Iris; Borri, Marcello; Borroni, Sara; Bortolotto, Valerio; Bos, Kors; Boscherini, Davide; Bosman, Martine; Boterenbrood, Hendrik; Bouchami, Jihene; Boudreau, Joseph; Bouhova-Thacker, Evelina Vassileva; Boumediene, Djamel Eddine; Bourdarios, Claire; Bousson, Nicolas; Boveia, Antonio; Boyd, James; Boyko, Igor; Bozovic-Jelisavcic, Ivanka; Bracinik, Juraj; Branchini, Paolo; Brandt, Andrew; Brandt, Gerhard; Brandt, Oleg; Bratzler, Uwe; Brau, Benjamin; Brau, James; Braun, Helmut; Brazzale, Simone Federico; Brelier, Bertrand; Bremer, Johan; Brendlinger, Kurt; Brenner, Richard; Bressler, Shikma; Britton, Dave; Brochu, Frederic; Brock, Ian; Brock, Raymond; Broggi, Francesco; Bromberg, Carl; Bronner, Johanna; Brooijmans, Gustaaf; Brooks, Timothy; Brooks, William; Brown, Gareth; Brown, Heather; Bruckman de Renstrom, Pawel; Bruncko, Dusan; Bruneliere, Renaud; Brunet, Sylvie; Bruni, Alessia; Bruni, Graziano; Bruschi, Marco; Buanes, Trygve; Buat, Quentin; Bucci, Francesca; Buchanan, James; Buchholz, Peter; Buckingham, Ryan; Buckley, Andrew; Buda, Stelian Ioan; Budagov, Ioulian; Budick, Burton; Büscher, Volker; Bugge, Lars; Bulekov, Oleg; Bundock, Aaron Colin; Bunse, Moritz; Buran, Torleiv; Burckhart, Helfried; Burdin, Sergey; Burgess, Thomas; Burke, Stephen; Busato, Emmanuel; Bussey, Peter; Buszello, Claus-Peter; Butler, Bart; Butler, John; Buttar, Craig; Butterworth, Jonathan; Buttinger, William; Cabrera Urbán, Susana; Caforio, Davide; Cakir, Orhan; Calafiura, Paolo; Calderini, Giovanni; Calfayan, Philippe; Calkins, Robert; Caloba, Luiz; Caloi, Rita; Calvet, David; Calvet, Samuel; Camacho Toro, Reina; Camarri, Paolo; Cameron, David; Caminada, Lea Michaela; Caminal Armadans, Roger; Campana, Simone; Campanelli, Mario; Canale, Vincenzo; Canelli, Florencia; Canepa, Anadi; Cantero, Josu; Cantrill, Robert; Capasso, Luciano; Capeans Garrido, Maria Del Mar; Caprini, Irinel; Caprini, Mihai; Capriotti, Daniele; Capua, Marcella; Caputo, Regina; Cardarelli, Roberto; Carli, Tancredi; Carlino, Gianpaolo; Carminati, Leonardo; Caron, Bryan; Caron, Sascha; Carquin, Edson; Carrillo Montoya, German D; Carter, Antony; Carter, Janet; Carvalho, João; Casadei, Diego; Casado, Maria Pilar; Cascella, Michele; Caso, Carlo; Castaneda Hernandez, Alfredo Martin; Castaneda-Miranda, Elizabeth; Castillo Gimenez, Victoria; Castro, Nuno Filipe; Cataldi, Gabriella; Catastini, Pierluigi; Catinaccio, Andrea; Catmore, James; Cattai, Ariella; Cattani, Giordano; Caughron, Seth; Cavaliere, Viviana; Cavalleri, Pietro; Cavalli, Donatella; Cavalli-Sforza, Matteo; Cavasinni, Vincenzo; Ceradini, Filippo; Santiago Cerqueira, Augusto; Cerri, Alessandro; Cerrito, Lucio; Cerutti, Fabio; Cetin, Serkant Ali; Chafaq, Aziz; Chakraborty, Dhiman; Chalupkova, Ina; Chan, Kevin; Chang, Philip; Chapleau, Bertrand; Chapman, John Derek; Chapman, John Wehrley; Chareyre, Eve; Charlton, Dave; Chavda, Vikash; Chavez Barajas, Carlos Alberto; Cheatham, Susan; Chekanov, Sergei; Chekulaev, Sergey; Chelkov, Gueorgui; Chelstowska, Magda Anna; Chen, Chunhui; Chen, Hucheng; Chen, Shenjian; Chen, Xin; Chen, Yujiao; Cheplakov, Alexander; Cherkaoui El Moursli, Rajaa; Chernyatin, Valeriy; Cheu, Elliott; Cheung, Sing-Leung; Chevalier, Laurent; Chiefari, Giovanni; Chikovani, Leila; Childers, John Taylor; Chilingarov, Alexandre; Chiodini, Gabriele; Chisholm, Andrew; Chislett, Rebecca Thalatta; Chitan, Adrian; Chizhov, Mihail; Choudalakis, Georgios; Chouridou, Sofia; Christidi, Illectra-Athanasia; Christov, Asen; Chromek-Burckhart, Doris; Chu, Ming-Lee; Chudoba, Jiri; Ciapetti, Guido; Ciftci, Abbas Kenan; Ciftci, Rena; Cinca, Diane; Cindro, Vladimir; Ciocca, Claudia; Ciocio, Alessandra; Cirilli, Manuela; Cirkovic, Predrag; Citterio, Mauro; Ciubancan, Mihai; Clark, Allan G; Clark, Philip James; Clarke, Robert; Cleland, Bill; Clemens, Jean-Claude; Clement, Benoit; Clement, Christophe; Coadou, Yann; Cobal, Marina; Coccaro, Andrea; Cochran, James H; Cogan, Joshua Godfrey; Coggeshall, James; Cogneras, Eric; Colas, Jacques; Cole, Stephen; Colijn, Auke-Pieter; Collins, Neil; Collins-Tooth, Christopher; Collot, Johann; Colombo, Tommaso; Colon, German; Conde Muiño, Patricia; Coniavitis, Elias; Conidi, Maria Chiara; Consonni, Sofia Maria; Consorti, Valerio; Constantinescu, Serban; Conta, Claudio; Conti, Geraldine; Conventi, Francesco; Cooke, Mark; Cooper, Ben; Cooper-Sarkar, Amanda; Copic, Katherine; Cornelissen, Thijs; Corradi, Massimo; Corriveau, Francois; Cortes-Gonzalez, Arely; Cortiana, Giorgio; Costa, Giuseppe; Costa, María José; Costanzo, Davide; Côté, David; Courneyea, Lorraine; Cowan, Glen; Cowden, Christopher; Cox, Brian; Cranmer, Kyle; Crescioli, Francesco; Cristinziani, Markus; Crosetti, Giovanni; Crépé-Renaudin, Sabine; Cuciuc, Constantin-Mihai; Cuenca Almenar, Cristóbal; Cuhadar Donszelmann, Tulay; Curatolo, Maria; Curtis, Chris; Cuthbert, Cameron; Cwetanski, Peter; Czirr, Hendrik; Czodrowski, Patrick; Czyczula, Zofia; D'Auria, Saverio; D'Onofrio, Monica; D'Orazio, Alessia; Da Cunha Sargedas De Sousa, Mario Jose; Da Via, Cinzia; Dabrowski, Wladyslaw; Dafinca, Alexandru; Dai, Tiesheng; Dallapiccola, Carlo; Dam, Mogens; Dameri, Mauro; Damiani, Daniel; Danielsson, Hans Olof; Dao, Valerio; Darbo, Giovanni; Darlea, Georgiana Lavinia; Dassoulas, James; Davey, Will; Davidek, Tomas; Davidson, Nadia; Davidson, Ruth; Davies, Eleanor; Davies, Merlin; Davignon, Olivier; Davison, Adam; Davygora, Yuriy; Dawe, Edmund; Dawson, Ian; Daya-Ishmukhametova, Rozmin; De, Kaushik; de Asmundis, Riccardo; De Castro, Stefano; De Cecco, Sandro; de Graat, Julien; De Groot, Nicolo; de Jong, Paul; De La Taille, Christophe; De la Torre, Hector; De Lorenzi, Francesco; de Mora, Lee; De Nooij, Lucie; De Pedis, Daniele; De Salvo, Alessandro; De Sanctis, Umberto; De Santo, Antonella; De Vivie De Regie, Jean-Baptiste; De Zorzi, Guido; Dearnaley, William James; Debbe, Ramiro; Debenedetti, Chiara; Dechenaux, Benjamin; Dedovich, Dmitri; Degenhardt, James; Del Papa, Carlo; Del Peso, Jose; Del Prete, Tarcisio; Delemontex, Thomas; Deliyergiyev, Maksym; Dell'Acqua, Andrea; Dell'Asta, Lidia; Della Pietra, Massimo; della Volpe, Domenico; Delmastro, Marco; Delsart, Pierre-Antoine; Deluca, Carolina; Demers, Sarah; Demichev, Mikhail; Demirkoz, Bilge; Deng, Jianrong; Denisov, Sergey; Derendarz, Dominik; Derkaoui, Jamal Eddine; Derue, Frederic; Dervan, Paul; Desch, Klaus Kurt; Devetak, Erik; Deviveiros, Pier-Olivier; Dewhurst, Alastair; DeWilde, Burton; Dhaliwal, Saminder; Dhullipudi, Ramasudhakar; Di Ciaccio, Anna; Di Ciaccio, Lucia; Di Girolamo, Alessandro; Di Girolamo, Beniamino; Di Luise, Silvestro; Di Mattia, Alessandro; Di Micco, Biagio; Di Nardo, Roberto; Di Simone, Andrea; Di Sipio, Riccardo; Diaz, Marco Aurelio; Diehl, Edward; Dietrich, Janet; Dietzsch, Thorsten; Diglio, Sara; Dindar Yagci, Kamile; Dingfelder, Jochen; Dinut, Florin; Dionisi, Carlo; Dita, Petre; Dita, Sanda; Dittus, Fridolin; Djama, Fares; Djobava, Tamar; Barros do Vale, Maria Aline; Do Valle Wemans, André; Doan, Thi Kieu Oanh; Dobbs, Matt; Dobinson, Robert; Dobos, Daniel; Dobson, Ellie; Dodd, Jeremy; Doglioni, Caterina; Doherty, Tom; Doi, Yoshikuni; Dolejsi, Jiri; Dolenc, Irena; Dolezal, Zdenek; Dolgoshein, Boris; Dohmae, Takeshi; Donadelli, Marisilvia; Donini, Julien; Dopke, Jens; Doria, Alessandra; Dos Anjos, Andre; Dotti, Andrea; Dova, Maria-Teresa; Doxiadis, Alexander; Doyle, Tony; Dris, Manolis; Dubbert, Jörg; Dube, Sourabh; Duchovni, Ehud; Duckeck, Guenter; Duda, Dominik; Dudarev, Alexey; Dudziak, Fanny; Dührssen, Michael; Duerdoth, Ian; Duflot, Laurent; Dufour, Marc-Andre; Duguid, Liam; Dunford, Monica; Duran Yildiz, Hatice; Duxfield, Robert; Dwuznik, Michal; Dydak, Friedrich; Düren, Michael; Ebke, Johannes; Eckweiler, Sebastian; Edmonds, Keith; Edson, William; Edwards, Clive; Edwards, Nicholas Charles; Ehrenfeld, Wolfgang; Eifert, Till; Eigen, Gerald; Einsweiler, Kevin; Eisenhandler, Eric; Ekelof, Tord; El Kacimi, Mohamed; Ellert, Mattias; Elles, Sabine; Ellinghaus, Frank; Ellis, Katherine; Ellis, Nicolas; Elmsheuser, Johannes; Elsing, Markus; Emeliyanov, Dmitry; Engelmann, Roderich; Engl, Albert; Epp, Brigitte; Erdmann, Johannes; Ereditato, Antonio; Eriksson, Daniel; Ernst, Jesse; Ernst, Michael; Ernwein, Jean; Errede, Deborah; Errede, Steven; Ertel, Eugen; Escalier, Marc; Esch, Hendrik; Escobar, Carlos; Espinal Curull, Xavier; Esposito, Bellisario; Etienne, Francois; Etienvre, Anne-Isabelle; Etzion, Erez; Evangelakou, Despoina; Evans, Hal; Fabbri, Laura; Fabre, Caroline; Fakhrutdinov, Rinat; Falciano, Speranza; Fang, Yaquan; Fanti, Marcello; Farbin, Amir; Farilla, Addolorata; Farley, Jason; Farooque, Trisha; Farrell, Steven; Farrington, Sinead; Farthouat, Philippe; Fassi, Farida; Fassnacht, Patrick; Fassouliotis, Dimitrios; Fatholahzadeh, Baharak; Favareto, Andrea; Fayard, Louis; Fazio, Salvatore; Febbraro, Renato; Federic, Pavol; Fedin, Oleg; Fedorko, Wojciech; Fehling-Kaschek, Mirjam; Feligioni, Lorenzo; Fellmann, Denis; Feng, Cunfeng; Feng, Eric; Fenyuk, Alexander; Ferencei, Jozef; Fernando, Waruna; Ferrag, Samir; Ferrando, James; Ferrara, Valentina; Ferrari, Arnaud; Ferrari, Pamela; Ferrari, Roberto; Ferreira de Lima, Danilo Enoque; Ferrer, Antonio; Ferrere, Didier; Ferretti, Claudio; Ferretto Parodi, Andrea; Fiascaris, Maria; Fiedler, Frank; Filipčič, Andrej; Filthaut, Frank; Fincke-Keeler, Margret; Fiolhais, Miguel; Fiorini, Luca; Firan, Ana; Fischer, Gordon; Fisher, Matthew; Flechl, Martin; Fleck, Ivor; Fleckner, Johanna; Fleischmann, Philipp; Fleischmann, Sebastian; Flick, Tobias; Floderus, Anders; Flores Castillo, Luis; Flowerdew, Michael; Fonseca Martin, Teresa; Formica, Andrea; Forti, Alessandra; Fortin, Dominique; Fournier, Daniel; Fox, Harald; Francavilla, Paolo; Franchini, Matteo; Franchino, Silvia; Francis, David; Frank, Tal; Franz, Sebastien; Fraternali, Marco; Fratina, Sasa; French, Sky; Friedrich, Conrad; Friedrich, Felix; Froeschl, Robert; Froidevaux, Daniel; Frost, James; Fukunaga, Chikara; Fullana Torregrosa, Esteban; Fulsom, Bryan Gregory; Fuster, Juan; Gabaldon, Carolina; Gabizon, Ofir; Gadfort, Thomas; Gadomski, Szymon; Gagliardi, Guido; Gagnon, Pauline; Galea, Cristina; Gallas, Elizabeth; Gallo, Valentina Santina; Gallop, Bruce; Gallus, Petr; Gan, KK; Gao, Yongsheng; Gaponenko, Andrei; Garberson, Ford; Garcia-Sciveres, Maurice; García, Carmen; García Navarro, José Enrique; Gardner, Robert; Garelli, Nicoletta; Garitaonandia, Hegoi; Garonne, Vincent; Gatti, Claudio; Gaudio, Gabriella; Gaur, Bakul; Gauthier, Lea; Gauzzi, Paolo; Gavrilenko, Igor; Gay, Colin; Gaycken, Goetz; Gazis, Evangelos; Ge, Peng; Gecse, Zoltan; Gee, Norman; Geerts, Daniël Alphonsus Adrianus; Geich-Gimbel, Christoph; Gellerstedt, Karl; Gemme, Claudia; Gemmell, Alistair; Genest, Marie-Hélène; Gentile, Simonetta; George, Matthias; George, Simon; Gerlach, Peter; Gershon, Avi; Geweniger, Christoph; Ghazlane, Hamid; Ghodbane, Nabil; Giacobbe, Benedetto; Giagu, Stefano; Giakoumopoulou, Victoria; Giangiobbe, Vincent; Gianotti, Fabiola; Gibbard, Bruce; Gibson, Adam; Gibson, Stephen; Gillberg, Dag; Gillman, Tony; Gingrich, Douglas; Ginzburg, Jonatan; Giokaris, Nikos; Giordani, MarioPaolo; Giordano, Raffaele; Giorgi, Francesco Michelangelo; Giovannini, Paola; Giraud, Pierre-Francois; Giugni, Danilo; Giunta, Michele; Giusti, Paolo; Gjelsten, Børge Kile; Gladilin, Leonid; Glasman, Claudia; Glatzer, Julian; Glazov, Alexandre; Glitza, Karl-Walter; Glonti, George; Goddard, Jack Robert; Godfrey, Jennifer; Godlewski, Jan; Goebel, Martin; Göpfert, Thomas; Goeringer, Christian; Gössling, Claus; Goldfarb, Steven; Golling, Tobias; Gomes, Agostinho; Gomez Fajardo, Luz Stella; Gonçalo, Ricardo; Goncalves Pinto Firmino Da Costa, Joao; Gonella, Laura; Gonzalez, Saul; González de la Hoz, Santiago; Gonzalez Parra, Garoe; Gonzalez Silva, Laura; Gonzalez-Sevilla, Sergio; Goodson, Jeremiah Jet; Goossens, Luc; Gorbounov, Petr Andreevich; Gordon, Howard; Gorelov, Igor; Gorfine, Grant; Gorini, Benedetto; Gorini, Edoardo; Gorišek, Andrej; Gornicki, Edward; Gosdzik, Bjoern; Goshaw, Alfred; Gosselink, Martijn; Gostkin, Mikhail Ivanovitch; Gough Eschrich, Ivo; Gouighri, Mohamed; Goujdami, Driss; Goulette, Marc Phillippe; Goussiou, Anna; Goy, Corinne; Gozpinar, Serdar; Grabowska-Bold, Iwona; Grafström, Per; Grahn, Karl-Johan; Grancagnolo, Francesco; Grancagnolo, Sergio; Grassi, Valerio; Gratchev, Vadim; Grau, Nathan; Gray, Heather; Gray, Julia Ann; Graziani, Enrico; Grebenyuk, Oleg; Greenshaw, Timothy; Greenwood, Zeno Dixon; Gregersen, Kristian; Gregor, Ingrid-Maria; Grenier, Philippe; Griffiths, Justin; Grigalashvili, Nugzar; Grillo, Alexander; Grinstein, Sebastian; Gris, Philippe Luc Yves; Grishkevich, Yaroslav; Grivaz, Jean-Francois; Gross, Eilam; Grosse-Knetter, Joern; Groth-Jensen, Jacob; Grybel, Kai; Guest, Daniel; Guicheney, Christophe; Guindon, Stefan; Gul, Umar; Guler, Hulya; Gunther, Jaroslav; Guo, Bin; Guo, Jun; Gutierrez, Phillip; Guttman, Nir; Gutzwiller, Olivier; Guyot, Claude; Gwenlan, Claire; Gwilliam, Carl; Haas, Andy; Haas, Stefan; Haber, Carl; Hadavand, Haleh Khani; Hadley, David; Haefner, Petra; Hahn, Ferdinand; Haider, Stefan; Hajduk, Zbigniew; Hakobyan, Hrachya; Hall, David; Haller, Johannes; Hamacher, Klaus; Hamal, Petr; Hamer, Matthias; Hamilton, Andrew; Hamilton, Samuel; Han, Liang; Hanagaki, Kazunori; Hanawa, Keita; Hance, Michael; Handel, Carsten; Hanke, Paul; Hansen, John Renner; Hansen, Jørgen Beck; Hansen, Jorn Dines; Hansen, Peter Henrik; Hansson, Per; Hara, Kazuhiko; Hare, Gabriel; Harenberg, Torsten; Harkusha, Siarhei; Harper, Devin; Harrington, Robert; Harris, Orin; Hartert, Jochen; Hartjes, Fred; Haruyama, Tomiyoshi; Harvey, Alex; Hasegawa, Satoshi; Hasegawa, Yoji; Hassani, Samira; Haug, Sigve; Hauschild, Michael; Hauser, Reiner; Havranek, Miroslav; Hawkes, Christopher; Hawkings, Richard John; Hawkins, Anthony David; Hawkins, Donovan; Hayakawa, Takashi; Hayashi, Takayasu; Hayden, Daniel; Hays, Chris; Hayward, Helen; Haywood, Stephen; He, Mao; Head, Simon; Hedberg, Vincent; Heelan, Louise; Heim, Sarah; Heinemann, Beate; Heisterkamp, Simon; Helary, Louis; Heller, Claudio; Heller, Matthieu; Hellman, Sten; Hellmich, Dennis; Helsens, Clement; Henderson, Robert; Henke, Michael; Henrichs, Anna; Henriques Correia, Ana Maria; Henrot-Versille, Sophie; Hensel, Carsten; Henß, Tobias; Medina Hernandez, Carlos; Hernández Jiménez, Yesenia; Herrberg, Ruth; Herten, Gregor; Hertenberger, Ralf; Hervas, Luis; Hesketh, Gavin Grant; Hessey, Nigel; Higón-Rodriguez, Emilio; Hill, John; Hiller, Karl Heinz; Hillert, Sonja; Hillier, Stephen; Hinchliffe, Ian; Hines, Elizabeth; Hirose, Minoru; Hirsch, Florian; Hirschbuehl, Dominic; Hobbs, John; Hod, Noam; Hodgkinson, Mark; Hodgson, Paul; Hoecker, Andreas; Hoeferkamp, Martin; Hoffman, Julia; Hoffmann, Dirk; Hohlfeld, Marc; Holder, Martin; Holmgren, Sven-Olof; Holy, Tomas; Holzbauer, Jenny; Hong, Tae Min; Hooft van Huysduynen, Loek; Horner, Stephan; Hostachy, Jean-Yves; Hou, Suen; Hoummada, Abdeslam; Howard, Jacob; Howarth, James; Hristova, Ivana; Hrivnac, Julius; Hryn'ova, Tetiana; Hsu, Pai-hsien Jennifer; Hsu, Shih-Chieh; Hu, Diedi; Hubacek, Zdenek; Hubaut, Fabrice; Huegging, Fabian; Huelsing, Tobias Alexander; Huettmann, Antje; Huffman, Todd Brian; Hughes, Emlyn; Hughes, Gareth; Huhtinen, Mika; Hurwitz, Martina; Husemann, Ulrich; Huseynov, Nazim; Huston, Joey; Huth, John; Iacobucci, Giuseppe; Iakovidis, Georgios; Ibbotson, Michael; Ibragimov, Iskander; Iconomidou-Fayard, Lydia; Idarraga, John; Iengo, Paolo; Igonkina, Olga; Ikegami, Yoichi; Ikeno, Masahiro; Iliadis, Dimitrios; Ilic, Nikolina; Ince, Tayfun; Inigo-Golfin, Joaquin; Ioannou, Pavlos; Iodice, Mauro; Iordanidou, Kalliopi; Ippolito, Valerio; Irles Quiles, Adrian; Isaksson, Charlie; Ishino, Masaya; Ishitsuka, Masaki; Ishmukhametov, Renat; Issever, Cigdem; Istin, Serhat; Ivashin, Anton; Iwanski, Wieslaw; Iwasaki, Hiroyuki; Izen, Joseph; Izzo, Vincenzo; Jackson, Brett; Jackson, John; Jackson, Paul; Jaekel, Martin; Jain, Vivek; Jakobs, Karl; Jakobsen, Sune; Jakoubek, Tomas; Jakubek, Jan; Jana, Dilip; Jansen, Eric; Jansen, Hendrik; Jantsch, Andreas; Janus, Michel; Jarlskog, Göran; Jeanty, Laura; Jen-La Plante, Imai; Jennens, David; Jenni, Peter; Loevschall-Jensen, Ask Emil; Jež, Pavel; Jézéquel, Stéphane; Jha, Manoj Kumar; Ji, Haoshuang; Ji, Weina; Jia, Jiangyong; Jiang, Yi; Jimenez Belenguer, Marcos; Jin, Shan; Jinnouchi, Osamu; Joergensen, Morten Dam; Joffe, David; Johansen, Marianne; Johansson, Erik; Johansson, Per; Johnert, Sebastian; Johns, Kenneth; Jon-And, Kerstin; Jones, Graham; Jones, Roger; Jones, Tim; Joram, Christian; Jorge, Pedro; Joshi, Kiran Daniel; Jovicevic, Jelena; Jovin, Tatjana; Ju, Xiangyang; Jung, Christian; Jungst, Ralph Markus; Juranek, Vojtech; Jussel, Patrick; Juste Rozas, Aurelio; Kabana, Sonja; Kaci, Mohammed; Kaczmarska, Anna; Kadlecik, Peter; Kado, Marumi; Kagan, Harris; Kagan, Michael; Kajomovitz, Enrique; Kalinin, Sergey; Kalinovskaya, Lidia; Kama, Sami; Kanaya, Naoko; Kaneda, Michiru; Kaneti, Steven; Kanno, Takayuki; Kantserov, Vadim; Kanzaki, Junichi; Kaplan, Benjamin; Kapliy, Anton; Kaplon, Jan; Kar, Deepak; Karagounis, Michael; Karakostas, Konstantinos; Karnevskiy, Mikhail; Kartvelishvili, Vakhtang; Karyukhin, Andrey; Kashif, Lashkar; Kasieczka, Gregor; Kass, Richard; Kastanas, Alex; Kataoka, Mayuko; Kataoka, Yousuke; Katsoufis, Elias; Katzy, Judith; Kaushik, Venkatesh; Kawagoe, Kiyotomo; Kawamoto, Tatsuo; Kawamura, Gen; Kayl, Manuel; Kazama, Shingo; Kazanin, Vassili; Kazarinov, Makhail; Keeler, Richard; Kehoe, Robert; Keil, Markus; Kekelidze, George; Keller, John; Kenyon, Mike; Kepka, Oldrich; Kerschen, Nicolas; Kerševan, Borut Paul; Kersten, Susanne; Kessoku, Kohei; Keung, Justin; Khalil-zada, Farkhad; Khandanyan, Hovhannes; Khanov, Alexander; Kharchenko, Dmitri; Khodinov, Alexander; Khomich, Andrei; Khoo, Teng Jian; Khoriauli, Gia; Khoroshilov, Andrey; Khovanskiy, Valery; Khramov, Evgeniy; Khubua, Jemal; Kim, Hyeon Jin; Kim, Shinhong; Kimura, Naoki; Kind, Oliver; King, Barry; King, Matthew; King, Robert Steven Beaufoy; Kirk, Julie; Kiryunin, Andrey; Kishimoto, Tomoe; Kisielewska, Danuta; Kitamura, Takumi; Kittelmann, Thomas; Kiuchi, Kenji; Kladiva, Eduard; Klein, Max; Klein, Uta; Kleinknecht, Konrad; Klemetti, Miika; Klier, Amit; Klimek, Pawel; Klimentov, Alexei; Klingenberg, Reiner; Klinger, Joel Alexander; Klinkby, Esben; Klioutchnikova, Tatiana; Klok, Peter; Klous, Sander; Kluge, Eike-Erik; Kluge, Thomas; Kluit, Peter; Kluth, Stefan; Knecht, Neil; Kneringer, Emmerich; Knoops, Edith; Knue, Andrea; Ko, Byeong Rok; Kobayashi, Tomio; Kobel, Michael; Kocian, Martin; Kodys, Peter; Köneke, Karsten; König, Adriaan; Koenig, Sebastian; Köpke, Lutz; Koetsveld, Folkert; Koevesarki, Peter; Koffas, Thomas; Koffeman, Els; Kogan, Lucy Anne; Kohlmann, Simon; Kohn, Fabian; Kohout, Zdenek; Kohriki, Takashi; Koi, Tatsumi; Kolachev, Guennady; Kolanoski, Hermann; Kolesnikov, Vladimir; Koletsou, Iro; Koll, James; Kollefrath, Michael; Komar, Aston; Komori, Yuto; Kondo, Takahiko; Kono, Takanori; Kononov, Anatoly; Konoplich, Rostislav; Konstantinidis, Nikolaos; Koperny, Stefan; Korcyl, Krzysztof; Kordas, Kostantinos; Korn, Andreas; Korol, Aleksandr; Korolkov, Ilya; Korolkova, Elena; Korotkov, Vladislav; Kortner, Oliver; Kortner, Sandra; Kostyukhin, Vadim; Kotov, Sergey; Kotov, Vladislav; Kotwal, Ashutosh; Kourkoumelis, Christine; Kouskoura, Vasiliki; Koutsman, Alex; Kowalewski, Robert Victor; Kowalski, Tadeusz; Kozanecki, Witold; Kozhin, Anatoly; Kral, Vlastimil; Kramarenko, Viktor; Kramberger, Gregor; Krasny, Mieczyslaw Witold; Krasznahorkay, Attila; Kraus, Jana; Kreiss, Sven; Krejci, Frantisek; Kretzschmar, Jan; Krieger, Nina; Krieger, Peter; Kroeninger, Kevin; Kroha, Hubert; Kroll, Joe; Kroseberg, Juergen; Krstic, Jelena; Kruchonak, Uladzimir; Krüger, Hans; Kruker, Tobias; Krumnack, Nils; Krumshteyn, Zinovii; Kubota, Takashi; Kuday, Sinan; Kuehn, Susanne; Kugel, Andreas; Kuhl, Thorsten; Kuhn, Dietmar; Kukhtin, Victor; Kulchitsky, Yuri; Kuleshov, Sergey; Kummer, Christian; Kuna, Marine; Kunkle, Joshua; Kupco, Alexander; Kurashige, Hisaya; Kurata, Masakazu; Kurochkin, Yurii; Kus, Vlastimil; Kuwertz, Emma Sian; Kuze, Masahiro; Kvita, Jiri; Kwee, Regina; La Rosa, Alessandro; La Rotonda, Laura; Labarga, Luis; Labbe, Julien; Lablak, Said; Lacasta, Carlos; Lacava, Francesco; Lacker, Heiko; Lacour, Didier; Lacuesta, Vicente Ramón; Ladygin, Evgueni; Lafaye, Remi; Laforge, Bertrand; Lagouri, Theodota; Lai, Stanley; Laisne, Emmanuel; Lamanna, Massimo; Lambourne, Luke; Lampen, Caleb; Lampl, Walter; Lancon, Eric; Landgraf, Ulrich; Landon, Murrough; Lane, Jenna; Lang, Valerie Susanne; Lange, Clemens; Lankford, Andrew; Lanni, Francesco; Lantzsch, Kerstin; Laplace, Sandrine; Lapoire, Cecile; Laporte, Jean-Francois; Lari, Tommaso; Larner, Aimee; Lassnig, Mario; Laurelli, Paolo; Lavorini, Vincenzo; Lavrijsen, Wim; Laycock, Paul; Le Dortz, Olivier; Le Guirriec, Emmanuel; Le Maner, Christophe; Le Menedeu, Eve; LeCompte, Thomas; Ledroit-Guillon, Fabienne Agnes Marie; Lee, Hurng-Chun; Lee, Jason; Lee, Shih-Chang; Lee, Lawrence; Lefebvre, Michel; Legendre, Marie; Legger, Federica; Leggett, Charles; Lehmacher, Marc; Lehmann Miotto, Giovanna; Lei, Xiaowen; Leite, Marco Aurelio Lisboa; Leitner, Rupert; Lellouch, Daniel; Lemmer, Boris; Lendermann, Victor; Leney, Katharine; Lenz, Tatiana; Lenzen, Georg; Lenzi, Bruno; Leonhardt, Kathrin; Leontsinis, Stefanos; Lepold, Florian; Leroy, Claude; Lessard, Jean-Raphael; Lester, Christopher; Lester, Christopher Michael; Levêque, Jessica; Levin, Daniel; Levinson, Lorne; Lewis, Adrian; Lewis, George; Leyko, Agnieszka; Leyton, Michael; Li, Bo; Li, Haifeng; Li, Shu; Li, Xuefei; Liang, Zhijun; Liao, Hongbo; Liberti, Barbara; Lichard, Peter; Lichtnecker, Markus; Lie, Ki; Liebig, Wolfgang; Limbach, Christian; Limosani, Antonio; Limper, Maaike; Lin, Simon; Linde, Frank; Linnemann, James; Lipeles, Elliot; Lipniacka, Anna; Liss, Tony; Lissauer, David; Lister, Alison; Litke, Alan; Liu, Chuanlei; Liu, Dong; Liu, Hao; Liu, Jianbei; Liu, Lulu; Liu, Minghui; Liu, Yanwen; Livan, Michele; Livermore, Sarah; Lleres, Annick; Llorente Merino, Javier; Lloyd, Stephen; Lobodzinska, Ewelina; Loch, Peter; Lockman, William; Loddenkoetter, Thomas; Loebinger, Fred; Loginov, Andrey; Loh, Chang Wei; Lohse, Thomas; Lohwasser, Kristin; Lokajicek, Milos; Lombardo, Vincenzo Paolo; Long, Robin Eamonn; Lopes, Lourenco; Lopez Mateos, David; Lorenz, Jeanette; Lorenzo Martinez, Narei; Losada, Marta; Loscutoff, Peter; Lo Sterzo, Francesco; Losty, Michael; Lou, Xinchou; Lounis, Abdenour; Loureiro, Karina; Love, Jeremy; Love, Peter; Lowe, Andrew; Lu, Feng; Lubatti, Henry; Luci, Claudio; Lucotte, Arnaud; Ludwig, Andreas; Ludwig, Dörthe; Ludwig, Inga; Ludwig, Jens; Luehring, Frederick; Luijckx, Guy; Lukas, Wolfgang; Lumb, Debra; Luminari, Lamberto; Lund, Esben; Lund-Jensen, Bengt; Lundberg, Björn; Lundberg, Johan; Lundberg, Olof; Lundquist, Johan; Lungwitz, Matthias; Lynn, David; Lytken, Else; Ma, Hong; Ma, Lian Liang; Maccarrone, Giovanni; Macchiolo, Anna; Maček, Boštjan; Machado Miguens, Joana; Mackeprang, Rasmus; Madaras, Ronald; Mader, Wolfgang; Maenner, Reinhard; Maeno, Tadashi; Mättig, Peter; Mättig, Stefan; Magnoni, Luca; Magradze, Erekle; Mahboubi, Kambiz; Mahmoud, Sara; Mahout, Gilles; Maiani, Camilla; Maidantchik, Carmen; Maio, Amélia; Majewski, Stephanie; Makida, Yasuhiro; Makovec, Nikola; Mal, Prolay; Malaescu, Bogdan; Malecki, Pawel; Malecki, Piotr; Maleev, Victor; Malek, Fairouz; Mallik, Usha; Malon, David; Malone, Caitlin; Maltezos, Stavros; Malyshev, Vladimir; Malyukov, Sergei; Mameghani, Raphael; Mamuzic, Judita; Manabe, Atsushi; Mandelli, Luciano; Mandić, Igor; Mandrysch, Rocco; Maneira, José; Mangeard, Pierre-Simon; Manhaes de Andrade Filho, Luciano; Manjarres Ramos, Joany Andreina; Mann, Alexander; Manning, Peter; Manousakis-Katsikakis, Arkadios; Mansoulie, Bruno; Mapelli, Alessandro; Mapelli, Livio; March, Luis; Marchand, Jean-Francois; Marchese, Fabrizio; Marchiori, Giovanni; Marcisovsky, Michal; Marino, Christopher; Marroquim, Fernando; Marshall, Zach; Martens, Kalen; Marti, Lukas Fritz; Marti-Garcia, Salvador; Martin, Brian; Martin, Brian Thomas; Martin, Jean-Pierre; Martin, Tim; Martin, Victoria Jane; Martin dit Latour, Bertrand; Martin-Haugh, Stewart; Martinez, Mario; Martinez Outschoorn, Verena; Martyniuk, Alex; Marx, Marilyn; Marzano, Francesco; Marzin, Antoine; Masetti, Lucia; Mashimo, Tetsuro; Mashinistov, Ruslan; Masik, Jiri; Maslennikov, Alexey; Massa, Ignazio; Massaro, Graziano; Massol, Nicolas; Mastrandrea, Paolo; Mastroberardino, Anna; Masubuchi, Tatsuya; Matricon, Pierre; Matsunaga, Hiroyuki; Matsushita, Takashi; Mattravers, Carly; Maurer, Julien; Maxfield, Stephen; Mayne, Anna; Mazini, Rachid; Mazur, Michael; Mazzaferro, Luca; Mazzanti, Marcello; Mc Donald, Jeffrey; Mc Kee, Shawn Patrick; McCarn, Allison; McCarthy, Robert; McCarthy, Tom; McCubbin, Norman; McFarlane, Kenneth; Mcfayden, Josh; Mchedlidze, Gvantsa; Mclaughlan, Tom; McMahon, Steve; McPherson, Robert; Meade, Andrew; Mechnich, Joerg; Mechtel, Markus; Medinnis, Mike; Meera-Lebbai, Razzak; Meguro, Tatsuma; Mehdiyev, Rashid; Mehlhase, Sascha; Mehta, Andrew; Meier, Karlheinz; Meirose, Bernhard; Melachrinos, Constantinos; Mellado Garcia, Bruce Rafael; Meloni, Federico; Mendoza Navas, Luis; Meng, Zhaoxia; Mengarelli, Alberto; Menke, Sven; Meoni, Evelin; Mercurio, Kevin Michael; Mermod, Philippe; Merola, Leonardo; Meroni, Chiara; Merritt, Frank; Merritt, Hayes; Messina, Andrea; Metcalfe, Jessica; Mete, Alaettin Serhan; Meyer, Carsten; Meyer, Christopher; Meyer, Jean-Pierre; Meyer, Jochen; Meyer, Joerg; Meyer, Thomas Christian; Miao, Jiayuan; Michal, Sebastien; Micu, Liliana; Middleton, Robin; Migas, Sylwia; Mijović, Liza; Mikenberg, Giora; Mikestikova, Marcela; Mikuž, Marko; Miller, David; Miller, Robert; Mills, Bill; Mills, Corrinne; Milov, Alexander; Milstead, David; Milstein, Dmitry; Minaenko, Andrey; Miñano Moya, Mercedes; Minashvili, Irakli; Mincer, Allen; Mindur, Bartosz; Mineev, Mikhail; Ming, Yao; Mir, Lluisa-Maria; Mirabelli, Giovanni; Mitrevski, Jovan; Mitsou, Vasiliki A; Mitsui, Shingo; Miyagawa, Paul; Mjörnmark, Jan-Ulf; Moa, Torbjoern; Moeller, Victoria; Mönig, Klaus; Möser, Nicolas; Mohapatra, Soumya; Mohr, Wolfgang; Moles-Valls, Regina; Monk, James; Monnier, Emmanuel; Montejo Berlingen, Javier; Monticelli, Fernando; Monzani, Simone; Moore, Roger; Moorhead, Gareth; Mora Herrera, Clemencia; Moraes, Arthur; Morange, Nicolas; Morel, Julien; Morello, Gianfranco; Moreno, Deywis; Moreno Llácer, María; Morettini, Paolo; Morgenstern, Marcus; Morii, Masahiro; Morley, Anthony Keith; Mornacchi, Giuseppe; Morris, John; Morvaj, Ljiljana; Moser, Hans-Guenther; Mosidze, Maia; Moss, Josh; Mount, Richard; Mountricha, Eleni; Mouraviev, Sergei; Moyse, Edward; Mueller, Felix; Mueller, James; Mueller, Klemens; Müller, Thomas; Mueller, Timo; Muenstermann, Daniel; Munwes, Yonathan; Murray, Bill; Mussche, Ido; Musto, Elisa; Myagkov, Alexey; Myska, Miroslav; Nadal, Jordi; Nagai, Koichi; Nagai, Ryo; Nagano, Kunihiro; Nagarkar, Advait; Nagasaka, Yasushi; Nagel, Martin; Nairz, Armin Michael; Nakahama, Yu; Nakamura, Koji; Nakamura, Tomoaki; Nakano, Itsuo; Nanava, Gizo; Napier, Austin; Narayan, Rohin; Nash, Michael; Nattermann, Till; Naumann, Thomas; Navarro, Gabriela; Neal, Homer; Nechaeva, Polina; Neep, Thomas James; Negri, Andrea; Negri, Guido; Negrini, Matteo; Nektarijevic, Snezana; Nelson, Andrew; Nelson, Timothy Knight; Nemecek, Stanislav; Nemethy, Peter; Nepomuceno, Andre Asevedo; Nessi, Marzio; Neubauer, Mark; Neumann, Manuel; Neusiedl, Andrea; Neves, Ricardo; Nevski, Pavel; Newman, Paul; Nguyen Thi Hong, Van; Nickerson, Richard; Nicolaidou, Rosy; Nicquevert, Bertrand; Niedercorn, Francois; Nielsen, Jason; Nikiforou, Nikiforos; Nikiforov, Andriy; Nikolaenko, Vladimir; Nikolic-Audit, Irena; Nikolics, Katalin; Nikolopoulos, Konstantinos; Nilsen, Henrik; Nilsson, Paul; Ninomiya, Yoichi; Nisati, Aleandro; Nisius, Richard; Nobe, Takuya; Nodulman, Lawrence; Nomachi, Masaharu; Nomidis, Ioannis; Norberg, Scarlet; Nordberg, Markus; Norton, Peter; Novakova, Jana; Nozaki, Mitsuaki; Nozka, Libor; Nugent, Ian Michael; Nuncio-Quiroz, Adriana-Elizabeth; Nunes Hanninger, Guilherme; Nunnemann, Thomas; Nurse, Emily; O'Brien, Brendan Joseph; O'Neale, Steve; O'Neil, Dugan; O'Shea, Val; Oakes, Louise Beth; Oakham, Gerald; Oberlack, Horst; Ocariz, Jose; Ochi, Atsuhiko; Oda, Susumu; Odaka, Shigeru; Odier, Jerome; Ogren, Harold; Oh, Alexander; Oh, Seog; Ohm, Christian; Ohshima, Takayoshi; Okawa, Hideki; Okumura, Yasuyuki; Okuyama, Toyonobu; Olariu, Albert; Olchevski, Alexander; Olivares Pino, Sebastian Andres; Oliveira, Miguel Alfonso; Oliveira Damazio, Denis; Oliver Garcia, Elena; Olivito, Dominick; Olszewski, Andrzej; Olszowska, Jolanta; Onofre, António; Onyisi, Peter; Oram, Christopher; Oreglia, Mark; Oren, Yona; Orestano, Domizia; Orlando, Nicola; Orlov, Iliya; Oropeza Barrera, Cristina; Orr, Robert; Osculati, Bianca; Ospanov, Rustem; Osuna, Carlos; Otero y Garzon, Gustavo; Ottersbach, John; Ouchrif, Mohamed; Ouellette, Eric; Ould-Saada, Farid; Ouraou, Ahmimed; Ouyang, Qun; Ovcharova, Ana; Owen, Mark; Owen, Simon; Ozcan, Veysi Erkcan; Ozturk, Nurcan; Pacheco Pages, Andres; Padilla Aranda, Cristobal; Pagan Griso, Simone; Paganis, Efstathios; Pahl, Christoph; Paige, Frank; Pais, Preema; Pajchel, Katarina; Palacino, Gabriel; Paleari, Chiara; Palestini, Sandro; Pallin, Dominique; Palma, Alberto; Palmer, Jody; Pan, Yibin; Panagiotopoulou, Evgenia; Pani, Priscilla; Panikashvili, Natalia; Panitkin, Sergey; Pantea, Dan; Papadelis, Aras; Papadopoulou, Theodora; Paramonov, Alexander; Paredes Hernandez, Daniela; Park, Woochun; Parker, Andy; Parodi, Fabrizio; Parsons, John; Parzefall, Ulrich; Pashapour, Shabnaz; Pasqualucci, Enrico; Passaggio, Stefano; Passeri, Antonio; Pastore, Fernanda; Pastore, Francesca; Pásztor, Gabriella; Pataraia, Sophio; Patel, Nikhul; Pater, Joleen; Patricelli, Sergio; Pauly, Thilo; Pecsy, Martin; Pedraza Lopez, Sebastian; Pedraza Morales, Maria Isabel; Peleganchuk, Sergey; Pelikan, Daniel; Peng, Haiping; Penning, Bjoern; Penson, Alexander; Penwell, John; Perantoni, Marcelo; Perez, Kerstin; Perez Cavalcanti, Tiago; Perez Codina, Estel; Pérez García-Estañ, María Teresa; Perez Reale, Valeria; Perini, Laura; Pernegger, Heinz; Perrino, Roberto; Perrodo, Pascal; Peshekhonov, Vladimir; Peters, Krisztian; Petersen, Brian; Petersen, Jorgen; Petersen, Troels; Petit, Elisabeth; Petridis, Andreas; Petridou, Chariclia; Petrolo, Emilio; Petrucci, Fabrizio; Petschull, Dennis; Petteni, Michele; Pezoa, Raquel; Phan, Anna; Phillips, Peter William; Piacquadio, Giacinto; Picazio, Attilio; Piccaro, Elisa; Piccinini, Maurizio; Piec, Sebastian Marcin; Piegaia, Ricardo; Pignotti, David; Pilcher, James; Pilkington, Andrew; Pina, João Antonio; Pinamonti, Michele; Pinder, Alex; Pinfold, James; Pinto, Belmiro; Pizio, Caterina; Plamondon, Mathieu; Pleier, Marc-Andre; Plotnikova, Elena; Poblaguev, Andrei; Poddar, Sahill; Podlyski, Fabrice; Poggioli, Luc; Pohl, David-leon; Pohl, Martin; Polesello, Giacomo; Policicchio, Antonio; Polini, Alessandro; Poll, James; Polychronakos, Venetios; Pomeroy, Daniel; Pommès, Kathy; Pontecorvo, Ludovico; Pope, Bernard; Popeneciu, Gabriel Alexandru; Popovic, Dragan; Poppleton, Alan; Portell Bueso, Xavier; Pospelov, Guennady; Pospisil, Stanislav; Potrap, Igor; Potter, Christina; Potter, Christopher; Poulard, Gilbert; Poveda, Joaquin; Pozdnyakov, Valery; Prabhu, Robindra; Pralavorio, Pascal; Pranko, Aliaksandr; Prasad, Srivas; Pravahan, Rishiraj; Prell, Soeren; Pretzl, Klaus Peter; Price, Darren; Price, Joe; Price, Lawrence; Prieur, Damien; Primavera, Margherita; Prokofiev, Kirill; Prokoshin, Fedor; Protopopescu, Serban; Proudfoot, James; Prudent, Xavier; Przybycien, Mariusz; Przysiezniak, Helenka; Psoroulas, Serena; Ptacek, Elizabeth; Pueschel, Elisa; Purdham, John; Purohit, Milind; Puzo, Patrick; Pylypchenko, Yuriy; Qian, Jianming; Quadt, Arnulf; Quarrie, David; Quayle, William; Quinonez, Fernando; Raas, Marcel; Radescu, Voica; Radloff, Peter; Rador, Tonguc; Ragusa, Francesco; Rahal, Ghita; Rahimi, Amir; Rahm, David; Rajagopalan, Srinivasan; Rammensee, Michael; Rammes, Marcus; Randle-Conde, Aidan Sean; Randrianarivony, Koloina; Rauscher, Felix; Rave, Tobias Christian; Raymond, Michel; Read, Alexander Lincoln; Rebuzzi, Daniela; Redelbach, Andreas; Redlinger, George; Reece, Ryan; Reeves, Kendall; Reinherz-Aronis, Erez; Reinsch, Andreas; Reisinger, Ingo; Rembser, Christoph; Ren, Zhongliang; Renaud, Adrien; Rescigno, Marco; Resconi, Silvia; Resende, Bernardo; Reznicek, Pavel; Rezvani, Reyhaneh; Richter, Robert; Richter-Was, Elzbieta; Ridel, Melissa; Rijpstra, Manouk; Rijssenbeek, Michael; Rimoldi, Adele; Rinaldi, Lorenzo; Rios, Ryan Randy; Riu, Imma; Rivoltella, Giancesare; Rizatdinova, Flera; Rizvi, Eram; Robertson, Steven; Robichaud-Veronneau, Andree; Robinson, Dave; Robinson, James; Robson, Aidan; Rocha de Lima, Jose Guilherme; Roda, Chiara; Roda Dos Santos, Denis; Roe, Adam; Roe, Shaun; Røhne, Ole; Rolli, Simona; Romaniouk, Anatoli; Romano, Marino; Romeo, Gaston; Romero Adam, Elena; Rompotis, Nikolaos; Roos, Lydia; Ros, Eduardo; Rosati, Stefano; Rosbach, Kilian; Rose, Anthony; Rose, Matthew; Rosenbaum, Gabriel; Rosenberg, Eli; Rosendahl, Peter Lundgaard; Rosenthal, Oliver; Rosselet, Laurent; Rossetti, Valerio; Rossi, Elvira; Rossi, Leonardo Paolo; Rotaru, Marina; Roth, Itamar; Rothberg, Joseph; Rousseau, David; Royon, Christophe; Rozanov, Alexander; Rozen, Yoram; Ruan, Xifeng; Rubbo, Francesco; Rubinskiy, Igor; Ruckstuhl, Nicole; Rud, Viacheslav; Rudolph, Christian; Rudolph, Gerald; Rühr, Frederik; Ruiz-Martinez, Aranzazu; Rumyantsev, Leonid; Rurikova, Zuzana; Rusakovich, Nikolai; Rutherfoord, John; Ruwiedel, Christoph; Ruzicka, Pavel; Ryabov, Yury; Rybar, Martin; Rybkin, Grigori; Ryder, Nick; Saavedra, Aldo; Sadeh, Iftach; Sadrozinski, Hartmut; Sadykov, Renat; Safai Tehrani, Francesco; Sakamoto, Hiroshi; Salamanna, Giuseppe; Salamon, Andrea; Saleem, Muhammad; Salek, David; Salihagic, Denis; Salnikov, Andrei; Salt, José; Salvachua Ferrando, Belén; Salvatore, Daniela; Salvatore, Pasquale Fabrizio; Salvucci, Antonio; Salzburger, Andreas; Sampsonidis, Dimitrios; Samset, Björn Hallvard; Sanchez, Arturo; Sanchez Martinez, Victoria; Sandaker, Heidi; Sander, Heinz Georg; Sanders, Michiel; Sandhoff, Marisa; Sandoval, Tanya; Sandoval, Carlos; Sandstroem, Rikard; Sankey, Dave; Sansoni, Andrea; Santamarina Rios, Cibran; Santoni, Claudio; Santonico, Rinaldo; Santos, Helena; Saraiva, João; Sarangi, Tapas; Sarkisyan-Grinbaum, Edward; Sarri, Francesca; Sartisohn, Georg; Sasaki, Osamu; Sasaki, Yuichi; Sasao, Noboru; Satsounkevitch, Igor; Sauvage, Gilles; Sauvan, Emmanuel; Sauvan, Jean-Baptiste; Savard, Pierre; Savinov, Vladimir; Savu, Dan Octavian; Sawyer, Lee; Saxon, David; Saxon, James; Sbarra, Carla; Sbrizzi, Antonio; Scannicchio, Diana; Scarcella, Mark; Schaarschmidt, Jana; Schacht, Peter; Schaefer, Douglas; Schäfer, Uli; Schaepe, Steffen; Schaetzel, Sebastian; Schaffer, Arthur; Schaile, Dorothee; Schamberger, R. Dean; Schamov, Andrey; Scharf, Veit; Schegelsky, Valery; Scheirich, Daniel; Schernau, Michael; Scherzer, Max; Schiavi, Carlo; Schieck, Jochen; Schioppa, Marco; Schlenker, Stefan; Schmidt, Evelyn; Schmieden, Kristof; Schmitt, Christian; Schmitt, Sebastian; Schmitz, Martin; Schneider, Basil; Schnoor, Ulrike; Schoening, Andre; Schorlemmer, Andre Lukas; Schott, Matthias; Schouten, Doug; Schovancova, Jaroslava; Schram, Malachi; Schroeder, Christian; Schroer, Nicolai; Schultens, Martin Johannes; Schultes, Joachim; Schultz-Coulon, Hans-Christian; Schulz, Holger; Schumacher, Markus; Schumm, Bruce; Schune, Philippe; Schwanenberger, Christian; Schwartzman, Ariel; Schwemling, Philippe; Schwienhorst, Reinhard; Schwierz, Rainer; Schwindling, Jerome; Schwindt, Thomas; Schwoerer, Maud; Sciolla, Gabriella; Scott, Bill; Searcy, Jacob; Sedov, George; Sedykh, Evgeny; Seidel, Sally; Seiden, Abraham; Seifert, Frank; Seixas, José; Sekhniaidze, Givi; Sekula, Stephen; Selbach, Karoline Elfriede; Seliverstov, Dmitry; Sellden, Bjoern; Sellers, Graham; Seman, Michal; Semprini-Cesari, Nicola; Serfon, Cedric; Serin, Laurent; Serkin, Leonid; Seuster, Rolf; Severini, Horst; Sfyrla, Anna; Shabalina, Elizaveta; Shamim, Mansoora; Shan, Lianyou; Shank, James; Shao, Qi Tao; Shapiro, Marjorie; Shatalov, Pavel; Shaw, Kate; Sherman, Daniel; Sherwood, Peter; Shibata, Akira; Shimizu, Shima; Shimojima, Makoto; Shin, Taeksu; Shiyakova, Maria; Shmeleva, Alevtina; Shochet, Mel; Short, Daniel; Shrestha, Suyog; Shulga, Evgeny; Shupe, Michael; Sicho, Petr; Sidoti, Antonio; Siegert, Frank; Sijacki, Djordje; Silbert, Ohad; Silva, José; Silver, Yiftah; Silverstein, Daniel; Silverstein, Samuel; Simak, Vladislav; Simard, Olivier; Simic, Ljiljana; Simion, Stefan; Simioni, Eduard; Simmons, Brinick; Simoniello, Rosa; Simonyan, Margar; Sinervo, Pekka; Sinev, Nikolai; Sipica, Valentin; Siragusa, Giovanni; Sircar, Anirvan; Sisakyan, Alexei; Sivoklokov, Serguei; Sjölin, Jörgen; Sjursen, Therese; Skinnari, Louise Anastasia; Skottowe, Hugh Philip; Skovpen, Kirill; Skubic, Patrick; Slater, Mark; Slavicek, Tomas; Sliwa, Krzysztof; Smakhtin, Vladimir; Smart, Ben; Smirnov, Sergei; Smirnov, Yury; Smirnova, Lidia; Smirnova, Oxana; Smith, Ben Campbell; Smith, Douglas; Smith, Kenway; Smizanska, Maria; Smolek, Karel; Snesarev, Andrei; Snow, Steve; Snow, Joel; Snyder, Scott; Sobie, Randall; Sodomka, Jaromir; Soffer, Abner; Solans, Carlos; Solar, Michael; Solc, Jaroslav; Soldatov, Evgeny; Soldevila, Urmila; Solfaroli Camillocci, Elena; Solodkov, Alexander; Solovyanov, Oleg; Solovyev, Victor; Soni, Nitesh; Sopko, Vit; Sopko, Bruno; Sosebee, Mark; Soualah, Rachik; Soukharev, Andrey; Spagnolo, Stefania; Spanò, Francesco; Spighi, Roberto; Spigo, Giancarlo; Spiwoks, Ralf; Spousta, Martin; Spreitzer, Teresa; Spurlock, Barry; St Denis, Richard Dante; Stahlman, Jonathan; Stamen, Rainer; Stanecka, Ewa; Stanek, Robert; Stanescu, Cristian; Stanescu-Bellu, Madalina; Stapnes, Steinar; Starchenko, Evgeny; Stark, Jan; Staroba, Pavel; Starovoitov, Pavel; Staszewski, Rafal; Staude, Arnold; Stavina, Pavel; Steele, Genevieve; Steinbach, Peter; Steinberg, Peter; Stekl, Ivan; Stelzer, Bernd; Stelzer, Harald Joerg; Stelzer-Chilton, Oliver; Stenzel, Hasko; Stern, Sebastian; Stewart, Graeme; Stillings, Jan Andre; Stockton, Mark; Stoerig, Kathrin; Stoicea, Gabriel; Stonjek, Stefan; Strachota, Pavel; Stradling, Alden; Straessner, Arno; Strandberg, Jonas; Strandberg, Sara; Strandlie, Are; Strang, Michael; Strauss, Emanuel; Strauss, Michael; Strizenec, Pavol; Ströhmer, Raimund; Strom, David; Strong, John; Stroynowski, Ryszard; Strube, Jan; Stugu, Bjarne; Stumer, Iuliu; Stupak, John; Sturm, Philipp; Styles, Nicholas Adam; Soh, Dart-yin; Su, Dong; Subramania, Halasya Siva; Succurro, Antonella; Sugaya, Yorihito; Suhr, Chad; Suk, Michal; Sulin, Vladimir; Sultansoy, Saleh; Sumida, Toshi; Sun, Xiaohu; Sundermann, Jan Erik; Suruliz, Kerim; Susinno, Giancarlo; Sutton, Mark; Suzuki, Yu; Suzuki, Yuta; Svatos, Michal; Swedish, Stephen; Sykora, Ivan; Sykora, Tomas; Sánchez, Javier; Ta, Duc; Tackmann, Kerstin; Taffard, Anyes; Tafirout, Reda; Taiblum, Nimrod; Takahashi, Yuta; Takai, Helio; Takashima, Ryuichi; Takeda, Hiroshi; Takeshita, Tohru; Takubo, Yosuke; Talby, Mossadek; Talyshev, Alexey; Tamsett, Matthew; Tanaka, Junichi; Tanaka, Reisaburo; Tanaka, Satoshi; Tanaka, Shuji; Tanasijczuk, Andres Jorge; Tani, Kazutoshi; Tannoury, Nancy; Tapprogge, Stefan; Tardif, Dominique; Tarem, Shlomit; Tarrade, Fabien; Tartarelli, Giuseppe Francesco; Tas, Petr; Tasevsky, Marek; Tassi, Enrico; Tatarkhanov, Mous; Tayalati, Yahya; Taylor, Christopher; Taylor, Frank; Taylor, Geoffrey; Taylor, Wendy; Teinturier, Marthe; Teischinger, Florian Alfred; Teixeira Dias Castanheira, Matilde; Teixeira-Dias, Pedro; Temming, Kim Katrin; Ten Kate, Herman; Teng, Ping-Kun; Terada, Susumu; Terashi, Koji; Terron, Juan; Testa, Marianna; Teuscher, Richard; Therhaag, Jan; Theveneaux-Pelzer, Timothée; Thoma, Sascha; Thomas, Juergen; Thompson, Emily; Thompson, Paul; Thompson, Peter; Thompson, Stan; Thomsen, Lotte Ansgaard; Thomson, Evelyn; Thomson, Mark; Thong, Wai Meng; Thun, Rudolf; Tian, Feng; Tibbetts, Mark James; Tic, Tomáš; Tikhomirov, Vladimir; Tikhonov, Yury; Timoshenko, Sergey; Tipton, Paul; Tisserant, Sylvain; Todorov, Theodore; Todorova-Nova, Sharka; Toggerson, Brokk; Tojo, Junji; Tokár, Stanislav; Tokushuku, Katsuo; Tollefson, Kirsten; Tomoto, Makoto; Tompkins, Lauren; Toms, Konstantin; Tonoyan, Arshak; Topfel, Cyril; Topilin, Nikolai; Torchiani, Ingo; Torrence, Eric; Torres, Heberth; Torró Pastor, Emma; Toth, Jozsef; Touchard, Francois; Tovey, Daniel; Trefzger, Thomas; Tremblet, Louis; Tricoli, Alesandro; Trigger, Isabel Marian; Trincaz-Duvoid, Sophie; Tripiana, Martin; Triplett, Nathan; Trischuk, William; Trocmé, Benjamin; Troncon, Clara; Trottier-McDonald, Michel; Trzebinski, Maciej; Trzupek, Adam; Tsarouchas, Charilaos; Tseng, Jeffrey; Tsiakiris, Menelaos; Tsiareshka, Pavel; Tsionou, Dimitra; Tsipolitis, Georgios; Tsiskaridze, Shota; Tsiskaridze, Vakhtang; Tskhadadze, Edisher; Tsukerman, Ilya; Tsulaia, Vakhtang; Tsung, Jieh-Wen; Tsuno, Soshi; Tsybychev, Dmitri; Tua, Alan; Tudorache, Alexandra; Tudorache, Valentina; Tuggle, Joseph; Turala, Michal; Turecek, Daniel; Turk Cakir, Ilkay; Turlay, Emmanuel; Turra, Ruggero; Tuts, Michael; Tykhonov, Andrii; Tylmad, Maja; Tyndel, Mike; Tzanakos, George; Uchida, Kirika; Ueda, Ikuo; Ueno, Ryuichi; Ugland, Maren; Uhlenbrock, Mathias; Uhrmacher, Michael; Ukegawa, Fumihiko; Unal, Guillaume; Undrus, Alexander; Unel, Gokhan; Unno, Yoshinobu; Urbaniec, Dustin; Usai, Giulio; Uslenghi, Massimiliano; Vacavant, Laurent; Vacek, Vaclav; Vachon, Brigitte; Vahsen, Sven; Valenta, Jan; Valentinetti, Sara; Valero, Alberto; Valkar, Stefan; Valladolid Gallego, Eva; Vallecorsa, Sofia; Valls Ferrer, Juan Antonio; Van Der Deijl, Pieter; van der Geer, Rogier; van der Graaf, Harry; Van Der Leeuw, Robin; van der Poel, Egge; van der Ster, Daniel; van Eldik, Niels; van Gemmeren, Peter; van Vulpen, Ivo; Vanadia, Marco; Vandelli, Wainer; Vaniachine, Alexandre; Vankov, Peter; Vannucci, Francois; Vari, Riccardo; Varol, Tulin; Varouchas, Dimitris; Vartapetian, Armen; Varvell, Kevin; Vassilakopoulos, Vassilios; Vazeille, Francois; Vazquez Schroeder, Tamara; Vegni, Guido; Veillet, Jean-Jacques; Veloso, Filipe; Veness, Raymond; Veneziano, Stefano; Ventura, Andrea; Ventura, Daniel; Venturi, Manuela; Venturi, Nicola; Vercesi, Valerio; Verducci, Monica; Verkerke, Wouter; Vermeulen, Jos; Vest, Anja; Vetterli, Michel; Vichou, Irene; Vickey, Trevor; Vickey Boeriu, Oana Elena; Viehhauser, Georg; Viel, Simon; Villa, Mauro; Villaplana Perez, Miguel; Vilucchi, Elisabetta; Vincter, Manuella; Vinek, Elisabeth; Vinogradov, Vladimir; Virchaux, Marc; Virzi, Joseph; Vitells, Ofer; Viti, Michele; Vivarelli, Iacopo; Vives Vaque, Francesc; Vlachos, Sotirios; Vladoiu, Dan; Vlasak, Michal; Vogel, Adrian; Vokac, Petr; Volpi, Guido; Volpi, Matteo; Volpini, Giovanni; von der Schmitt, Hans; von Radziewski, Holger; von Toerne, Eckhard; Vorobel, Vit; Vorwerk, Volker; Vos, Marcel; Voss, Rudiger; Voss, Thorsten Tobias; Vossebeld, Joost; Vranjes, Nenad; Vranjes Milosavljevic, Marija; Vrba, Vaclav; Vreeswijk, Marcel; Vu Anh, Tuan; Vuillermet, Raphael; Vukotic, Ilija; Wagner, Wolfgang; Wagner, Peter; Wahlen, Helmut; Wahrmund, Sebastian; Wakabayashi, Jun; Walch, Shannon; Walder, James; Walker, Rodney; Walkowiak, Wolfgang; Wall, Richard; Waller, Peter; Walsh, Brian; Wang, Chiho; Wang, Haichen; Wang, Hulin; Wang, Jike; Wang, Jin; Wang, Rui; Wang, Song-Ming; Wang, Tan; Warburton, Andreas; Ward, Patricia; Warsinsky, Markus; Washbrook, Andrew; Wasicki, Christoph; Watanabe, Ippei; Watkins, Peter; Watson, Alan; Watson, Ian; Watson, Miriam; Watts, Gordon; Watts, Stephen; Waugh, Anthony; Waugh, Ben; Weber, Michele; Weber, Pavel; Weidberg, Anthony; Weigell, Philipp; Weingarten, Jens; Weiser, Christian; Wellenstein, Hermann; Wells, Phillippa; Wenaus, Torre; Wendland, Dennis; Weng, Zhili; Wengler, Thorsten; Wenig, Siegfried; Wermes, Norbert; Werner, Matthias; Werner, Per; Werth, Michael; Wessels, Martin; Wetter, Jeffrey; Weydert, Carole; Whalen, Kathleen; Wheeler-Ellis, Sarah Jane; White, Andrew; White, Martin; White, Sebastian; Whitehead, Samuel Robert; Whiteson, Daniel; Whittington, Denver; Wicek, Francois; Wicke, Daniel; Wickens, Fred; Wiedenmann, Werner; Wielers, Monika; Wienemann, Peter; Wiglesworth, Craig; Wiik-Fuchs, Liv Antje Mari; Wijeratne, Peter Alexander; Wildauer, Andreas; Wildt, Martin Andre; Wilhelm, Ivan; Wilkens, Henric George; Will, Jonas Zacharias; Williams, Eric; Williams, Hugh; Willis, William; Willocq, Stephane; Wilson, John; Wilson, Michael Galante; Wilson, Alan; Wingerter-Seez, Isabelle; Winkelmann, Stefan; Winklmeier, Frank; Wittgen, Matthias; Wollstadt, Simon Jakob; Wolter, Marcin Wladyslaw; Wolters, Helmut; Wong, Wei-Cheng; Wooden, Gemma; Wosiek, Barbara; Wotschack, Jorg; Woudstra, Martin; Wozniak, Krzysztof; Wraight, Kenneth; Wright, Michael; Wrona, Bozydar; Wu, Sau Lan; Wu, Xin; Wu, Yusheng; Wulf, Evan; Wynne, Benjamin; Xella, Stefania; Xiao, Meng; Xie, Song; Xu, Chao; Xu, Da; Yabsley, Bruce; Yacoob, Sahal; Yamada, Miho; Yamaguchi, Hiroshi; Yamamoto, Akira; Yamamoto, Kyoko; Yamamoto, Shimpei; Yamamura, Taiki; Yamanaka, Takashi; Yamaoka, Jared; Yamazaki, Takayuki; Yamazaki, Yuji; Yan, Zhen; Yang, Haijun; Yang, Un-Ki; Yang, Yi; Yang, Zhaoyu; Yanush, Serguei; Yao, Liwen; Yao, Yushu; Yasu, Yoshiji; Ybeles Smit, Gabriel Valentijn; Ye, Jingbo; Ye, Shuwei; Yilmaz, Metin; Yoosoofmiya, Reza; Yorita, Kohei; Yoshida, Riktura; Young, Charles; Young, Christopher John; Youssef, Saul; Yu, Dantong; Yu, Jaehoon; Yu, Jie; Yuan, Li; Yurkewicz, Adam; Byszewski, Marcin; Zabinski, Bartlomiej; Zaidan, Remi; Zaitsev, Alexander; Zajacova, Zuzana; Zanello, Lucia; Zaytsev, Alexander; Zeitnitz, Christian; Zeman, Martin; Zemla, Andrzej; Zendler, Carolin; Zenin, Oleg; Ženiš, Tibor; Zinonos, Zinonas; Zenz, Seth; Zerwas, Dirk; Zevi della Porta, Giovanni; Zhan, Zhichao; Zhang, Dongliang; Zhang, Huaqiao; Zhang, Jinlong; Zhang, Xueyao; Zhang, Zhiqing; Zhao, Long; Zhao, Tianchi; Zhao, Zhengguo; Zhemchugov, Alexey; Zhong, Jiahang; Zhou, Bing; Zhou, Ning; Zhou, Yue; Zhu, Cheng Guang; Zhu, Hongbo; Zhu, Junjie; Zhu, Yingchun; Zhuang, Xuai; Zhuravlov, Vadym; Zieminska, Daria; Zimin, Nikolai; Zimmermann, Robert; Zimmermann, Simone; Zimmermann, Stephanie; Ziolkowski, Michael; Zitoun, Robert; Živković, Lidija; Zmouchko, Viatcheslav; Zobernig, Georg; Zoccoli, Antonio; zur Nedden, Martin; Zutshi, Vishnu; Zwalinski, Lukasz

    2013-08-06

    The measurement of several event shape variables is presented in minimum bias pp collisions at a center-of-mass energy of 7 TeV using the ATLAS detector at the LHC. The observables studied are the transverse thrust, thrust minor and transverse sphericity, each defined using the momenta perpendicular to the beam direction of the final state charged particles. Events with at least six charged particles are selected. In addition to the differential distributions, the evolution of each event shape variable as a function of the leading charged particle transverse momentum, charged particle multiplicity and summed transverse momentum is presented. Predictions from several Monte Carlo models have been compared with data and they show significant deviations from data.

  1. Interindividual variability of soil arsenic metabolism by human gut microbiota using SHIME model.

    Science.gov (United States)

    Yin, Naiyi; Du, Huili; Wang, Pengfei; Cai, Xiaolin; Chen, Peng; Sun, Guoxin; Cui, Yanshan

    2017-10-01

    Arsenic (As) metabolism by human gut microbiota has been evidenced with in vitro experiments from contaminated soils. In this study, the variability in the metabolic potency toward As-contaminated soils and gut microbial diversity were investigated between healthy individuals (Adult versus Child). Arsenic bioaccessibility in the colon phase increased by 1.4-6.8 and 1.2-8.7 folds for adult and child, respectively. We found a high degree of As methylation for the colon digests of the adult (mean 2 μg methylarsenicals/hr/g biomass), 3-folds higher than that of the child. Besides, arsenite [As(III)] concentration (1.5-391.3 μg/L) for the child was 2-18 times for the adult. 16S rRNA gene sequencing revealed that human gut microbiota from 20 various genera potentially had resistance genes to reduce and methylate As under conservative statistics. Our results indicated that As metabolism by gut microbiota from adult and child was significantly different. The adult gut microbiota had a great ability of As methylation; the child gut microbiota exhibited high As(III) level, which could encounter high health risk. The identity and activity of arsenic-metabolizing bacteria isolated from human gut and its homologous role in As metabolism need be further explored. This study provides a better understanding of health risk assessment to adults and children upon soil As exposures. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. The methods of geomorphometry and digital soil mapping for assessing spatial variability in the properties of agrogray soils on a slope

    Science.gov (United States)

    Gopp, N. V.; Nechaeva, T. V.; Savenkov, O. A.; Smirnova, N. V.; Smirnov, V. V.

    2017-01-01

    The relationships between the morphometric parameters (MPs) of topography calculated on the basis of digital elevation model (ASTER GDEM, 30 m) and the properties of the plow layer of agrogray soils on a slope were analyzed. The contribution of MPs to the spatial variability of the soil moisture reached 42%; to the content of physical clay (exchangeable potassium, 45%; to the content of exchangeable calcium, 67%; to the content of exchangeable magnesium, 40%; and to the soil pH, 42%. A comparative analysis of the plow layer within the eluvial and transitional parts of the slope was performed with the use of geomorphometric methods and digital soil mapping. The regression analysis showed statistically significant correlations between the properties of the plow layer and the MPs describing surface runoff, geometric forms of surface, and the soil temperature regime.

  3. Study Variability of Seasonal Soil Moisture in Ensemble of CMIP5 Models Over South Asia During 1950-2005

    Science.gov (United States)

    Fahim, A. M.; Shen, R.; Yue, Z.; Di, W.; Mushtaq Shah, S.

    2015-12-01

    Moisture in the upper most layer of soil column from 14 different models under Coupled Model Intercomparison Project Phase-5 (CMIP5) project were analyzed for four seasons of the year. Aim of this study was to explore variability in soil moisture over south Asia using multi model ensemble and relationship between summer rainfall and soil moisture for spring and summer season. GLDAS (Global Land Data Assimilation System) dataset set was used for comparing CMIP5 ensemble mean soil moisture in different season. Ensemble mean represents soil moisture well in accordance with the geographical features; prominent arid regions are indicated profoundly. Empirical Orthogonal Function (EOF) analysis was applied to study the variability. First component of EOF explains 17%, 16%, 11% and 11% variability for spring, summer, autumn and winter season respectively. Analysis reveal increasing trend in soil moisture over most parts of Afghanistan, Central and north western parts of Pakistan, northern India and eastern to south eastern parts of China, in spring season. During summer, south western part of India exhibits highest negative trend while rest of the study area show minute trend (increasing or decreasing). In autumn, south west of India is under highest negative loadings. During winter season, north western parts of study area show decreasing trend. Summer rainfall has very week (negative or positive) spatial correlation, with spring soil moisture, while possess higher correlation with summer soil moisture. Our studies have significant contribution to understand complex nature of land - atmosphere interactions, as soil moisture prediction plays an important role in the cycle of sink and source of many air pollutants. Next level of research should be on filling the gaps between accurately measuring the soil moisture using satellite remote sensing and land surface modelling. Impact of soil moisture in tracking down different types of pollutant will also be studied.

  4. Physically-based parameterization of spatially variable soil and vegetation using satellite multispectral data

    Science.gov (United States)

    Jasinski, Michael F.; Eagleson, Peter S.

    1989-01-01

    A stochastic-geometric landsurface reflectance model is formulated and tested for the parameterization of spatially variable vegetation and soil at subpixel scales using satellite multispectral images without ground truth. Landscapes are conceptualized as 3-D Lambertian reflecting surfaces consisting of plant canopies, represented by solid geometric figures, superposed on a flat soil background. A computer simulation program is developed to investigate image characteristics at various spatial aggregations representative of satellite observational scales, or pixels. The evolution of the shape and structure of the red-infrared space, or scattergram, of typical semivegetated scenes is investigated by sequentially introducing model variables into the simulation. The analytical moments of the total pixel reflectance, including the mean, variance, spatial covariance, and cross-spectral covariance, are derived in terms of the moments of the individual fractional cover and reflectance components. The moments are applied to the solution of the inverse problem: The estimation of subpixel landscape properties on a pixel-by-pixel basis, given only one multispectral image and limited assumptions on the structure of the landscape. The landsurface reflectance model and inversion technique are tested using actual aerial radiometric data collected over regularly spaced pecan trees, and using both aerial and LANDSAT Thematic Mapper data obtained over discontinuous, randomly spaced conifer canopies in a natural forested watershed. Different amounts of solar backscattered diffuse radiation are assumed and the sensitivity of the estimated landsurface parameters to those amounts is examined.

  5. Método da adsorção de césio para determinação da carga estrutural em solos altamente intemperizados Method of cesium adsorption for determination of structural charge in highly weathered soils

    Directory of Open Access Journals (Sweden)

    Oscarlina Lúcia dos Santos Weber

    2005-01-01

    Full Text Available O conhecimento das cargas elétricas, permanente e variável, é fundamental para a compreensão e previsão do destino de elementos químicos no solo. Foram investigadas propriedades de carga de superfície de dois Latossolos Vermelhos acriférricos, dois Latossolos Amarelos ácricos e um Nitossolo Vermelho eutroférrico, usado como referência, por apresentar carga predominantemente permanente. Essas amostras foram investigadas pelo método da adsorção do íon césio (Cs+, que mede a carga estrutural permanente (sigmaO. O método baseia-se na preferência de sítios siloxanos de superfície para Cs+ sobre Li+ e de grupos de superfície ionizáveis de menor seletividade ao íon Cs+. Nos Latossolos acriférricos, a carga permanente diminuiu à medida que o índice de intemperização (Ki diminuiu. O método da adsorção de césio quantificou significativa carga permanente, mesmo em solos altamente intemperizados.The knowledge of permanent and variable charge is of high importance to a better understanding of the fate of chemical elements in soil. Four Brazilian Oxisols presenting acric character were investigated by an ion adsorption method that measures the structural charge density (sigmaO and were compared to an Alfisol (NV, which had predominantly permanent charge. The method is based on the preference of siloxane surface sites for cesium over lithium and on the lower selectivity of ionizable surface group for the ion cesium. In the Acrudoxes, the permanent charge decreased as the weathering index (Ki decreased. The cesium adsorption method quantified significant amounts of structural charge, even in highly weathered soils.

  6. Variability of Effective Micro-organisms (EM) in bokashi and soil and effects on soil-borne plant pathogens

    NARCIS (Netherlands)

    Shin, Keumchul; Diepen, van G.; Blok, W.; Bruggen, van A.H.C.

    2017-01-01

    The microbial inoculant ‘Effective Microorganisms’ (EM) has been used to promote soil fertility and plant growth in agriculture. We tested effects of commercial EM products on suppression of soil-borne diseases, microbial activity and bacterial composition in organically managed sandy soils. EM was

  7. Assessing Climate Change Impacts on Large-Scale Soil Moisture, its Temporal Variability and Associated Drought-Flood Risks

    Science.gov (United States)

    Destouni, G.; Verrot, L.

    2015-12-01

    Soil moisture is a dynamic variable of great importance for water cycling and climate, as well as for ecosystems and societal sectors such as agriculture. Model representation of soil moisture and its temporal variability is, for instance, central for assessing the impacts of hydro-climatic change on drought and flood risks. However, our ability to assess such impacts and guide appropriate mitigation and adaptation measures is challenged by the need to link data and modeling across a range of spatiotemporal scales of relevance for the variability and change of soil moisture in long-term time series. This paper synthesizes recent advances for meeting this challenge by a relatively simple, analytical, data-driven approach to modeling the variability and change of large-scale soil moisture under long-term hydro-climatic change. Model application to two major Swedish drainage basins, and model-data comparison for ten study catchments across the United States shows the model ability to reproduce variability dynamics in long-term data series of the key soil-moisture variables: unsaturated water content and groundwater table position. The Swedish application shows that human-driven hydro-climatic shifts may imply increased risk for hydrological drought (runoff-related) and agricultural drought (soil moisture-related), even though meteorological drought risk (precipitation-related) is unchanged or lowered. The direct model-data comparison for ten U.S. catchments further shows good model representation of seasonal and longer-term fluctuation timings and frequencies for water content and groundwater level, along with physically reasonable model tendency to underestimate the local fluctuation magnitudes. Overall, the tested modeling approach can fulfill its main aim of screening long-term time series of large-scale hydro-climatic data (historic or projected for the future by climate modeling) for relatively simple, unexaggerated assessment of variability and change in key

  8. Light-Induced Charged and Trap States in Colloidal Nanocrystals Detected by Variable Pulse Rate Photoluminescence Spectroscopy

    NARCIS (Netherlands)

    Saba, Michele; Aresti, Mauro; Quochi, Francesco; Marceddu, Marco; Loi, Maria Antonietta; Huang, Jing; Talapin, Dmitri V.; Mura, Andrea; Bongiovanni, Giovanni

    Intensity instabilities are a common trademark of the photoluminescence of nanoemitters. This general behavior is commonly attributed to random fluctuations of free charges and activation of charge traps reducing the emission yield intermittently. However, the actual physical origin of this

  9. Spatial and temporal variability of throughfall and soil moisture in a deciduous forest in the low mountain ranges (Hesse, Germany)

    Science.gov (United States)

    Chifflard, Peter; Weishaupt, Philipp; Reiss, Martin

    2017-04-01

    Spatial and temporal patterns of throughfall can affect the heterogeneity of ecological, biogeochemical and hydrological processes at a forest floor and further the underlying soil. Previous research suggests different factors controlling the spatial and temporal patterns of throughfall, but most studies focus on coniferous forest, where the vegetation coverage is more or less constant over time. In deciduous forests the leaf area index varies due to the leaf fall in autumn which implicates a specific spatial and temporal variability of throughfall and furthermore of the soil moisture. Therefore, in the present study, the measurements of throughfall and soil moisture in a deciduous forest in the low mountain ranges focused especially on the period of leaf fall. The aims of this study were: 1) to detect the spatial and temporal variability of both the throughfall and the soil moisture, 2) to examine the temporal stability of the spatial patterns of the throughfall and soil moisture and 3) relate the soil moisture patterns to the throughfall patterns and further to the canopy characteristics. The study was carried out in a small catchment on middle Hesse (Germany) which is covered by beech forest. Annual mean air temperature is 9.4°C (48.9˚F) and annual mean precipitation is 650 mm. Base materials for soil genesis is greywacke and clay shale from Devonian deposits. The soil type at the study plot is a shallow cambisol. The study plot covers an area of about 150 m2 where 77 throughfall samplers where installed. The throughfall and the soil moisture (FDR-method, 20 cm depth) was measured immediately after every rainfall event at the 77 measurement points. During the period of October to December 2015 altogether 7 events were investigated. The geostatistical method kriging was used to interpolate between the measurements points to visualize the spatial patterns of each investigated parameter. Time-stability-plots were applied to examine temporal scatters of each

  10. High-frequency analysis of the complex linkage between soil CO(2) fluxes, photosynthesis and environmental variables.

    Science.gov (United States)

    Martin, Jonathan G; Phillips, Claire L; Schmidt, Andres; Irvine, James; Law, Beverly E

    2012-01-01

    High-frequency soil CO(2) flux data are valuable for providing new insights into the processes of soil CO(2) production. A record of hourly soil CO(2) fluxes from a semi-arid ponderosa pine stand was spatially and temporally deconstructed in attempts to determine if variation could be explained by logical drivers using (i) CO(2) production depths, (ii) relationships and lags between fluxes and soil temperatures, or (iii) the role of canopy assimilation in soil CO(2) flux variation. Relationships between temperature and soil fluxes were difficult to establish at the hourly scale because diel cycles of soil fluxes varied seasonally, with the peak of flux rates occurring later in the day as soil water content decreased. Using a simple heat transport/gas diffusion model to estimate the time and depth of CO(2) flux production, we determined that the variation in diel soil CO(2) flux patterns could not be explained by changes in diffusion rates or production from deeper soil profiles. We tested for the effect of gross ecosystem productivity (GEP) by minimizing soil flux covariance with temperature and moisture using only data from discrete bins of environmental conditions (±1 °C soil temperature at multiple depths, precipitation-free periods and stable soil moisture). Gross ecosystem productivity was identified as a possible driver of variability at the hourly scale during the growing season, with multiple lags between ~5, 15 and 23 days. Additionally, the chamber-specific lags between GEP and soil CO(2) fluxes appeared to relate to combined path length for carbon flow (top of tree to chamber center). In this sparse and heterogeneous forested system, the potential link between CO(2) assimilation and soil CO(2) flux may be quite variable both temporally and spatially. For model applications, it is important to note that soil CO(2) fluxes are influenced by many biophysical factors, which may confound or obscure relationships with logical environmental drivers and act at

  11. A small-scale geostatistical analysis of the variability of soil properties driving the biogenic emission of nitric oxide from soil

    Science.gov (United States)

    Behrendt, T.; Bargsten, A.; Mamtimin, B.; Andreae, M. O.; Bruse, M.; Meixner, F. X.

    2009-04-01

    It is well known that the main steering parameters for the biogenic emission of nitrogen oxide (NO) from the soil are soil moisture, soil temperature, soil organic matter (SOM), soil nutrients, as well as soil texture and the vegetation cover. Following controlled incubation and fumigation experiments on soil samples, laboratory derived parameterization of the net NO release rate in terms of soil moisture, soil temperature and the loss in ignition (as a raw estimate of SOM) enable the calculation of net potential NO fluxes from soil. At the experimental-site „Weidenbrunnen", a mountainous spruce forest located in the Fichtelgebirge (Germany), 142 samples of organic matter and topsoil were collected. The study area (120 x 140 m) was sub-divided into three units according to differences in vegetation and insolation, as well as the position of tracks. For the sampling procedure a nested sampling design with grid intervals of 20 m, 5 m and 1.25 m was chosen. The soil properties that were analysed included the variability of the organic matter thickness, pH, C/N-ratio, loss in ignition, texture, soil temperature and top soil moisture, as well as bulk density. The relief and the understorey were included as external factors. Furthermore, the terrain elevation was measured with a TruePulse360° Laser along a geostatistical grid using supporting points in 8 different directions. Of 4 supporting points into 8 different directions, one data point was placed every 5 m. We was used this grid structure to interpolate the contour lines and identified southern exposition and a micro hilly relief (DEM). The understorey mapping was calculated by the triangulation-method while the area between the trees was divided into triangles. First of all, an experimental variogram of the appropriate grid intervals was constructed. Through the development of a model function it is possible to assign a variogram value to every distance. Across that theoretical function a spatial interpolation

  12. Blast load effects research in dry and wet soil

    CSIR Research Space (South Africa)

    Ahmed, R

    2014-09-01

    Full Text Available measured. One such variable is the soil moisture content when considering buried charges. Tests were conducted on 8 kg charges buried in both wet and dry soils at three different Stand-Off Distances (SOD). The measured impulse was consistently higher...

  13. Probing quantum chromodynamics with the ATLAS detector. Charged-particle event shape variables and the dijet cross-section

    Energy Technology Data Exchange (ETDEWEB)

    Huelsing, Tobias

    2015-01-22

    Quantum chromodynamics, QCD, the theory of the strong interaction is split into two regimes. Scattering processes of the proton constituents, the partons, with a high momentum transfer Q{sup 2} can be calculated and predicted with perturbative calculations. At low momentum transfers between the scattering particles perturbation theory is not applicable anymore, and phenomenological methods are used to describe the physics in this regime. The ATLAS experiment at the Large Hadron Collider, LHC, provides the possibility to analyze QCD processes at both ends of the momentum scale. Two measurements are presented in this thesis, emphasizing one of the two regimes each: The measurement of charged-particle event shape variables in inelastic proton-proton collisions at a center-of-mass energy of √(s)=7 TeV analyses the transverse momentum flow and structure of hadronic events. Due to the, on average, low momentum transfer, predictions of these events are mainly driven by non-perturbative models. Three event shapes are studied: The transverse thrust, the thrust minor and the transverse sphericity. Data recorded during low pile-up beam conditions in early 2010, corresponding to an integrated luminosity of 168 μb, is analyzed. Charged particles with a transverse momentum above 500 MeV are used to compute the event shape variables. In addition to differential event shape distributions in p{sub T} of the highest-transverse-momentum particle, the evolution of each event shape variable as a function of charged particle multiplicity and summed transverse momentum is presented. Predictions from different Monte Carlo models are compared with data and they show significant deviations from data. Using the results to tune the free parameters of the phenomenological models can improve future Monte Carlo predictions and give additional insight to the non-perturbative part of the QCD. The measurement of the double-differential dijet cross section as function of the dijet mass and

  14. Effectiveness of using pedo-transfer functions to quantify the spatial variability of soil water retention characteristics

    Science.gov (United States)

    Romano, Nunzio; Santini, Alessandro

    1997-12-01

    Accurate knowledge of soil hydraulic properties is of crucial importance for reliable applications of recently developed distributed models to environmental studies and land-use planning. To provide such information in a cost-effective way, indirect estimation of water transport parameters from easily measurable or already available soil data using pedo-transfer functions (PTFs) is becoming increasingly popular. However, distributed hydrological modeling requires that soil hydraulic characterization also takes account of the description of spatial variability. The objective of this study was to evaluate some published PTFs in the light of their ability to quantify the spatial structure and variability of soil water retention adequately. Four PTFs were tested: two provided only values of water content at specific pressure potentials (PTF Group A), whereas the remaining two estimated the parameters of closed-form relations describing the water retention function (PTF Group B). Measured data for testing were obtained from undisturbed soil samples taken from the top layer of different soils along a 5 km transect with constant spacing of 50 m. Overall, summary statistics and sample distributions of the PTF-estimated retention characteristics at selected pressure potentials are close to those of the retention variables used as reference for comparisons. The largest discrepancies are related to the use of PTFs pertaining to Group A. Although the quality of kriged interpolations based on soil property data obtained by simplified methodologies still gives cause for concern, results show that the structure of spatial variability exhibited by the variables considered along the study transect is described well enough when using PTFs for determining soil water retention characteristics.

  15. Variability in soil-water retention properties and implications for physics-based simulation of landslide early warning criteria

    Science.gov (United States)

    Thomas, Matthew A.; Mirus, Benjamin B.; Collins, Brian D.; Lu, Ning; Godt, Jonathan W.

    2018-01-01

    Rainfall-induced shallow landsliding is a persistent hazard to human life and property. Despite the observed connection between infiltration through the unsaturated zone and shallow landslide initiation, there is considerable uncertainty in how estimates of unsaturated soil-water retention properties affect slope stability assessment. This source of uncertainty is critical to evaluating the utility of physics-based hydrologic modeling as a tool for landslide early warning. We employ a numerical model of variably saturated groundwater flow parameterized with an ensemble of texture-, laboratory-, and field-based estimates of soil-water retention properties for an extensively monitored landslide-prone site in the San Francisco Bay Area, CA, USA. Simulations of soil-water content, pore-water pressure, and the resultant factor of safety show considerable variability across and within these different parameter estimation techniques. In particular, we demonstrate that with the same permeability structure imposed across all simulations, the variability in soil-water retention properties strongly influences predictions of positive pore-water pressure coincident with widespread shallow landsliding. We also find that the ensemble of soil-water retention properties imposes an order-of-magnitude and nearly two-fold variability in seasonal and event-scale landslide susceptibility, respectively. Despite the reduced factor of safety uncertainty during wet conditions, parameters that control the dry end of the soil-water retention function markedly impact the ability of a hydrologic model to capture soil-water content dynamics observed in the field. These results suggest that variability in soil-water retention properties should be considered for objective physics-based simulation of landslide early warning criteria.

  16. Intraspecific variability of popcorn S7 lines for phosphorus efficiency in the soil.

    Science.gov (United States)

    Gerhardt, I F S; Júnior, A T Amaral; Guimarães, L J M; Schwantes, I A; Santos, A; Kamphorst, S H; Lima, V J; Poblete, F M; Myers, G O

    2017-09-27

    The expansion of agriculture, coupled with the need for sustainable cropping, is one of the greatest challenges of the scientific community working on the generation of new cultivars adapted to abiotic stress conditions. The aim of this study was to evaluate the variability of popcorn lines as to responsiveness and efficiency in phosphorus use, as a first step towards the implementation of a breeding program interested in the practice of sustainable agriculture. Twenty-five popcorn lines were evaluated in two locations with different phosphorus levels in the soil, using a randomized block design. The following traits were measured: plant height, ear height, female flowering date, male flowering date, male-female flowering interval, ear diameter, ear length, 100-grain weight, grain yield, popping expansion, and expanded popcorn volume per hectare. A combined analysis of variance and test of means were performed, and the lines were classified as to their phosphorus use efficiency, according to their production performance in the different environments. The genetic diversity between the lines was estimated by Tocher's and UPGMA clustering methods, using generalized Mahalanobis distance. Lines L59, P7, P2, P3, P4, P8, P10, P9, L66, L70, L69, and P5 were efficient and responsive, whereas lines L75, L80, L61, L77, L63, L65, P1, L54, L53, L88, and L71 were inefficient and nonresponsive. Genetic variability was greater in the environments with low phosphorus in the soil, suggesting that the selection pressure exerted in the stressing environment is a decisive factor to obtain a higher expression of variability.

  17. Spatial variability of soil magnetic susceptibility in an agricultural field located in Eastern Ukraine

    Science.gov (United States)

    Menshov, Oleksandr; Pereira, Paulo; Kruglov, Oleksandr

    2015-04-01

    Magnetic susceptibility (MS) have been used to characterize soil properties. It gives an indirect information about heavy metals content and degree of human impacts on soil contamination derived from atmospheric pollution (Girault et al., 2011). This method is inexpensive in relation to chemical analysis and very useful to track soil pollution, since several toxic components deposited on soil surface are rich in particulates produced by oxidation processes (Boyko et al., 2004; Morton-Bernea et al., 2009). Thus, identify the spatial distribution of MS is of major importance, since can give an indirect information of high metals content (Dankoub et al., 2012). This allows also to distinguish the pedogenic and technogenic origin magnetic signal. For example Ukraine chernozems contain fine-grained oxidized magnetite and maghemite of pedogenic origin formed by weathering of the parent material (Jeleńska et al., 2004). However, to a correct understanding of variables distribution, the identification of the most accurate interpolation method is fundamental for a better interpretation of map information (Pereira et al., 2013). The objective of this work is to study the spatial variability of soil MS in an agricultural fields located in the Tcherkascy Tishki area (50.11°N, 36.43 °E, 162 m a.s.l), Ukraine. Soil MS was measured in 77 sampling points in a north facing slope. To estimate the best interpolation method, several interpolation methods were tested, as inverse distance to a weight (IDW) with the power of 1,2,3,4 and 5, Local Polynomial (LP) with the power of 1 and 2, Global Polynomial (GP), radial basis functions - spline with tension (SPT), completely regularized spline (CRS), multiquatratic (MTQ), inverse multiquatratic (IMTQ), and thin plate spline (TPS) - and some geostatistical methods as, ordinary kriging (OK), Simple Kriging (SK) and Universal Kriging (UK), used in previous works (Pereira et al., 2014). On average, the soil MS of the studied plot had 686

  18. Into the Deep: Variability in Soil Microbial Communities and Carbon Turnover Along a Tropical Forest Soil Depth Profile

    Science.gov (United States)

    Pett-Ridge, J.; McFarlane, K. J.; Heckman, K. A.; Reed, S.; Wood, T. E.

    2015-12-01

    Tropical forest soils store more carbon (C) than any other terrestrial ecosystem and exchange vast amounts of CO2, water, and energy with the atmosphere. Much of this C is leached and stored within deeper soil layers, but we know exceedingly little about the fate of this C or the microbial communities that drive deep soil biogeochemistry. From the data that do exist, most organic matter (OM) in tropical soils appears associated with mineral particles, suggesting deep soils may provide greater C stabilization due to organo-metal co-precipitation and mineral-surface interactions. However, few studies have evaluated sub-surface soils in tropical ecosystems, the turnover times of deep soil C, and sensitivity of this C to global environmental change. To address this critical research need, we quantified C pools, microbial communities and soil radiocarbon turnover times in bulk soils and soil fractions [free light (unprotected), dense (mineral-associated)] from 0-140 cm in replicate soil pits in the Luquillo Experimental Forest, Puerto Rico. Unsurprisingly, we found soil C, nitrogen, and root and microbial biomass all declined exponentially with depth; total C stocks dropped from 5.5 % at the surface to temperate deciduous forests, these 14C values reflect far older soil C, and OM decomposition that highly favors free light C pools, even at depth. While previous work suggests these low C tropical subsoils contain small but metabolically active microbial communities at depths of ~100cm, these organisms appear highly OM limited, and preferentially degrade recent inputs. In the coming half century, tropical forests are predicted to see a 2 - 5 ° C temperature increase and substantial differences in rainfall amount and timing. The data described here represent baseline data for a site now undergoing a 4°C warming experiment; upcoming research will examine soil C storage and mean residence times during and post-warming to improve numerical models of ecosystem warming

  19. Neural network and Monte Carlo simulation approach to investigate variability of copper concentration in phytoremediated contaminated soils.

    Science.gov (United States)

    Hattab, Nour; Hambli, Ridha; Motelica-Heino, Mikael; Mench, Michel

    2013-11-15

    The statistical variation of soil properties and their stochastic combinations may affect the extent of soil contamination by metals. This paper describes a method for the stochastic analysis of the effects of the variation in some selected soil factors (pH, DOC and EC) on the concentration of copper in dwarf bean leaves (phytoavailability) grown in the laboratory on contaminated soils treated with different amendments. The method is based on a hybrid modeling technique that combines an artificial neural network (ANN) and Monte Carlo Simulations (MCS). Because the repeated analyses required by MCS are time-consuming, the ANN is employed to predict the copper concentration in dwarf bean leaves in response to stochastic (random) combinations of soil inputs. The input data for the ANN are a set of selected soil parameters generated randomly according to a Gaussian distribution to represent the parameter variabilities. The output is the copper concentration in bean leaves. The results obtained by the stochastic (hybrid) ANN-MCS method show that the proposed approach may be applied (i) to perform a sensitivity analysis of soil factors in order to quantify the most important soil parameters including soil properties and amendments on a given metal concentration, (ii) to contribute toward the development of decision-making processes at a large field scale such as the delineation of contaminated sites. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Use of geophysical survey as a predictor of the edaphic properties variability in soils used for livestock production

    Energy Technology Data Exchange (ETDEWEB)

    Peralta, N.R.; Cicore, P.L.; Marino, M.A.; Marques da Silva, J. R.; Costa, J.L.

    2015-07-01

    The spatial variability in soils used for livestock production (i.e. Natraquoll and Natraqualf) at farm and paddock scale is usually very high. Understanding this spatial variation within a field is the first step for site-specific crop management. For this reason, we evaluated whether apparent electrical conductivity (ECa), a widely used proximal soil sensing technology, is a potential estimator of the edaphic variability in these types of soils. ECa and elevation data were collected in a paddock of 16 ha. Elevation was negatively associated with ECa. Geo-referenced soil samples were collected and analyzed for soil organic matter (OM) content, pH, the saturation extract electrical conductivity (ECext), available phosphorous (P), and anaerobically incubated Nitrogen (Nan). Relationships between soil properties and ECa were analyzed using regression analysis, principal components analysis (PCA), and stepwise regression. Principal components (PC) and the PC-stepwise were used to determine which soil properties have an important influence on ECa. In this experiment elevation was negatively associated with ECa. The data showed that pH, OM, and ECext exhibited a high correlation with ECa (R2=0.76; 0.70 and 0.65, respectively). Whereas P and Nan showed a lower correlation (R2=0.54 and 0.11 respectively). The model resulting from the PC-stepwise regression analysis explained slightly more than 69% of the total variation of the measured ECa, only retaining PC1. Therefore, ECext, pH and OM were considered key latent variables because they substantially influence the relationship between the PC1 and the ECa (loading factors>0.4). Results showed that ECa is associated with the spatial distribution of some important soil properties. Thus, ECa can be used as a support tool to implement site-specific management in soils for livestock use. (Author)

  1. Use of geophysical survey as a predictor of the edaphic properties variability in soils used for livestock production

    Directory of Open Access Journals (Sweden)

    Nahuel R. Peralta

    2015-12-01

    Full Text Available The spatial variability in soils used for livestock production (i.e. Natraquoll and Natraqualf at farm and paddock scale is usually very high. Understanding this spatial variation within a field is the first step for site-specific crop management. For this reason, we evaluated whether apparent electrical conductivity (ECa, a widely used proximal soil sensing technology, is a potential estimator of the edaphic variability in these types of soils. ECa and elevation data were collected in a paddock of 16 ha. Elevation was negatively associated with ECa. Geo-referenced soil samples were collected and analyzed for soil organic matter (OM content, pH, the saturation extract electrical conductivity (ECext, available phosphorous (P, and anaerobically incubated Nitrogen (Nan. Relationships between soil properties and ECa were analyzed using regression analysis, principal components analysis (PCA, and stepwise regression. Principal components (PC and the PC-stepwise were used to determine which soil properties have an important influence on ECa. In this experiment elevation was negatively associated with ECa. The data showed that pH, OM, and ECext exhibited a high correlation with ECa (R2=0.76; 0.70 and 0.65, respectively. Whereas P and Nan showed a lower correlation (R2=0.54 and 0.11 respectively. The model resulting from the PC-stepwise regression analysis explained slightly more than 69% of the total variation of the measured ECa, only retaining PC1. Therefore, ECext, pH and OM were considered key latent variables because they substantially influence the relationship between the PC1 and the ECa (loading factors>0.4. Results showed that ECa is associated with the spatial distribution of some important soil properties. Thus, ECa can be used as a support tool to implement site-specific management in soils for livestock use.

  2. Geochemistry and spatial variability of metal(loid) concentrations in soils of the state of Minas Gerais, Brazil.

    Science.gov (United States)

    de Souza, José João Lelis Leal; Abrahão, Walter Antônio Pereira; de Mello, Jaime Wilson Vargas; da Silva, Juscimar; da Costa, Liovando Marciano; de Oliveira, Teógenes Senna

    2015-02-01

    Since 2009 a policy has been implemented in Brazil to establish the natural concentrations of potentially toxic substances in soil for each state. Historically a 'mining state', Minas Gerais established a Quality Reference Value for metal(loid)s for all of the soils in the state. To successfully establish these values it is important to study the spatial geochemical diversity for the state. In this context, the objectives of this work are: (1) to evaluate the natural concentrations of metal(loid)s in pristine Minas Gerais soils and (2) to interpret the spatial variability in concentration of these elements. The 0-20 cm layer of soils was sampled for 697 georeferenced sites including the main geological materials and soil groups. Soil properties were analyzed according to methodologies suitable for Brazilian soils. The concentration of metal(loid)s was determined by acid extraction according to EPA 3051A. Descriptive statistics, Pearson correlation and spatial variability analyses were performed. The dominance of acidic pH and low CEC values reflects the pervasive deep acid weathering. The variability of metal(loid) concentrations for soils of the state may be attributed to geological diversity and different pedogenesis. Correlation and spatial analysis indicated that the Fe concentration is strongly associated with metal(loid) concentrations in topsoil. According to the spatial geochemical diversity of the state, a k-means cluster analysis was performed which identified four clusters. A significant difference in the mean values of metal(loid) concentrations between the clusters confirmed that the single Quality Reference Value established does not represent the geochemical diversity of soils in Minas Gerais. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Spatial and temporal variability of grass cover in two olive grove catchments on contrasting soil types

    Science.gov (United States)

    Aguilera, Laura; Taguas, Encarnación V.; Gimeno, Enrique; Gómez, José A.

    2013-04-01

    Mediterranean climate conditions -characterized by the concentration of the precipitation in the seasons of autumn and spring, the low temperatures in winter and extremely warm and dry summers- determine that ground cover by adventitious (or cover crop) vegetation shows significant seasonal and annual variability. In addition, its spatial variability associates also, partially, to water availability among the landscape. This is especially relevant in olive orchards, an agricultural system under high erosion risk in the region where the establishment of herbaceous cover has proved to improve soil protection reducing erosion risk, as well as the improvement of soil properties (Gómez et al., 2009). All these benefits are based on small scale studies where full ground cover by the cover crop is relatively easy to obtain. However, few information is available about the actual ground cover achieved at farm scale, although preliminary observations suggests that this might be extremely variable (Gómez and Giráldez, 2009). This study presents the preliminary results evaluating the spatial and temporal evolution of ground cover by adventitious vegetation (the preferred option by farmers to achieve a cover crop) in two commercial olive farms during 2 hydrological years (2011-2012). The study was conducted in two farms located in the province of Cordoba, Southern Spain. Both were olive orchards grown under deficit irrigation systems and present a gauge station where rainfall, runoff and sediment loads have been measured from the year 2005. The soil management in "La Conchuela" farm was based in the use of herbicide in the line of olive trees to keep the bare soil all year round, and the application of selective herbicide in the lane between the olive trees to promote the grown of graminaceae grasses . In addition, the grass is mechanically killed in June. In the another farm, "Arroyo Blanco", the grass spontaneous cover is allowed until mid-spring in which is also

  4. Spatial variability of physical and chemical properties in soils of the experimental farm in the magdalena university (santa marta, colombia)

    OpenAIRE

    Vásquez Polo, José Rafael; Baena Garcia, Diosdado; Menjivar Flores, Juan Carlos

    2011-01-01

    We have studied the spatial variability of agricultural soils in the experimental farm at Magdalena University (Santa Marta, Colombia; 74° 07' – 74° 12' W, 11° 11' – 11° 15' N). Analyzed soil properties included: gravimetric soil moisture content, grain size analysis, bulk density, resistance to root penetration, hydraulic conductivity, organic matter content, pH, cation exchange capacity, total N and P, exchangeable cations (Ca+2, Mg+2, K+, Na+), metals (Cu, Zn, Fe , Mn) and B content. Sampl...

  5. The effects of the sub-grid variability of soil and land cover data on agricultural droughts in Germany

    Science.gov (United States)

    Kumar, Rohini; Samaniego, Luis; Zink, Matthias

    2013-04-01

    Simulated soil moisture from land surface or water balance models is increasingly used to characterize and/or monitor the development of agricultural droughts at regional and global scales (e.g. NLADS, EDO, GLDAS). The skill of these models to accurately replicate hydrologic fluxes and state variables is strongly dependent on the quality meteorological forcings, the conceptualization of dominant processes, and the parameterization scheme used to incorporate the variability of land surface properties (e.g. soil, topography, and vegetation) at a coarser spatial resolutions (e.g. at least 4 km). The goal of this study is to analyze the effects of the sub-grid variability of soil texture and land cover properties on agricultural drought statistics such as duration, severity, and areal extent. For this purpose, a process based mesoscale hydrologic model (mHM) is used to create two sets of daily soil moisture fields over Germany at the spatial resolution of (4 × 4) km2 from 1950 to 2011. These simulations differ from each other only on the manner in which the land surface properties are accounted within the model. In the first set, soil moisture fields are obtained with the multiscale parameter regionalization (MPR) scheme (Samaniego, et. al. 2010, Kumar et. al. 2012), which explicitly takes the sub-grid variability of soil texture and land cover properties into account. In the second set, on the contrary, a single dominant soil and land cover class is used for ever grid cell at 4 km. Within each set, the propagation of the parameter uncertainty into the soil moisture simulations is also evaluated using an ensemble of 100 best global parameter sets of mHM (Samaniego, et. al. 2012). To ensure comparability, both sets of this ensemble simulations are forced with the same fields of meteorological variables (e.g., precipitation, temperature, and potential evapotranspiration). Results indicate that both sets of model simulations, with and without the sub-grid variability of

  6. Modeling and mapping of cadmium in soils based on qualitative and quantitative auxiliary variables in a cadmium contaminated area.

    Science.gov (United States)

    Cao, Shanshan; Lu, Anxiang; Wang, Jihua; Huo, Lili

    2017-02-15

    The aim of this study was to measure the improvement in mapping accuracy of spatial distribution of Cd in soils by using geostatistical methods combined with auxiliary factors, especially qualitative variables. Significant correlations between Cd content and correlation environment variables that are easy to obtain (such as topographic factors, distance to residential area, land use types and soil types) were analyzed systematically and quantitatively. Based on 398 samples collected from a Cd contaminated area (Hunan Province, China), we estimated the spatial distribution of Cd in soils by using spatial interpolation models, including ordinary kriging (OK), and regression kriging (RK) with each auxiliary variable, all quantitative variables (RKWQ) and all auxiliary variables (RKWA). Results showed that mapping with RK was more consistent with the sampling data of the spatial distribution of Cd in the study area than mapping with OK. The performance indicators (smaller mean error, mean absolute error, root mean squared error values and higher relative improvement of RK than OK) indicated that the introduction of auxiliary variables can improve the prediction accuracy of Cd in soils for which the spatial structure could not be well captured by point-based observation (nugget to sill ratio=0.76) and strong relationships existed between variables to be predicted and auxiliary variables. The comparison of RKWA with RKWQ further indicated that the introduction of qualitative variables improved the prediction accuracy, and even weakened the effects of quantitative factors. Furthermore, the significantly different relative improvement with similar R2 and varying spatial dependence showed that a reasonable choice of auxiliary variables and analysis of spatial structure of regression residuals are equally important to ensure accurate predictions. Copyright © 2016. Published by Elsevier B.V.

  7. Pro-glacial soil variability and geomorphic activity - the case of three Swiss valleys

    NARCIS (Netherlands)

    Temme, A.J.A.M.; Lange, de K.

    2014-01-01

    Soils in pro-glacial areas are often approached from a chronosequence viewpoint. In the chronosequence approach, the objective is to derive rates of soil formation from differences in properties between soils of different age. For this reason, in chronosequence studies, soils are sampled in

  8. Quantifying the impact of soil and climate variability on rainfed rice production

    NARCIS (Netherlands)

    Wopereis, M.C.S.

    1993-01-01

    Methods and sampling strategies for measurement of soil hydraulic functions in puddled and non-puddled rice soils are discussed. A method was developed to measure in situ water percolation rate and soil water pressure head gradients in puddled soils. The number of measurements needed to

  9. Hyper-temporal remote sensing for digital soil mapping: Characterizing soil-vegetation response to climatic variability

    Science.gov (United States)

    Indices derived from remotely-sensed imagery are commonly used to predict soil properties with digital soil mapping (DSM) techniques. The use of images from single dates or a small number of dates is most common for DSM; however, selection of the appropriate images is complicated by temporal variabi...

  10. The response of archaeal species to seasonal variables in a subtropical aerated soil: insight into the low abundant methanogens.

    Science.gov (United States)

    Xie, Wei; Jiao, Na; Ma, Cenling; Fang, Sa; Phelps, Tommy J; Zhu, Ruixin; Zhang, Chuanlun

    2017-08-01

    Archaea are cosmopolitan in aerated soils around the world. While the dominance of Thaumarchaeota has been reported in most soils, the methanogens are recently found to be ubiquitous but with low abundances in the aerated soil globally. However, the seasonal changes of Archaea community in the aerated soils are still in the mist. In this study, we investigated the change of Archaea in the context of environmental variables over a period of 12 months in a subtropical soil on the Chongming Island, China. The results showed that Nitrososphaera spp. were the dominant archaeal population while the methanogens were in low proportions but highly diverse (including five genera: Methanobacterium, Methanocella, Methanosaeta, Methanosarcina, and Methanomassiliicoccus) in the aerated soil samples determined by high throughput sequencing. A total of 126 LSA correlations were found in the dataset including all the 72 archaeal OTUs and 8 environmental factors. A significance index defined as the pagerank score of each OTU divided by its relative abundance was used to evaluate the significance of each OTU. The results showed that five out of 17 methanogen OTUs were significantly positively correlated with temperature, suggesting those methanogens might increase with temperature rather than being dormant in the aerated soils. Given the metabolic response of methanogens to temperature under aerated soil conditions, their contribution to the global methane cycle warrants evaluation.

  11. Annual and seasonal variability of metals and metalloids in urban and industrial soils in Alcalá de Henares (Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Peña-Fernández, A. [Departamento de Ciencias Biomédicas, Unidad de Toxicología, Universidad de Alcalá, Crta. Madrid-Barcelona Km, 33.6, 28871 Alcalá de Henares, Madrid (Spain); Lobo-Bedmar, M.C. [Instituto Madrileño de Investigación y Desarrollo Rural Agrario y Alimentario (IMIDRA), Finca el Encín, Crta. Madrid-Barcelona Km, 38.2, 28800 Alcalá de Henares, Madrid (Spain); González-Muñoz, M.J., E-mail: mariajose.gonzalez@uah.es [Departamento de Ciencias Biomédicas, Unidad de Toxicología, Universidad de Alcalá, Crta. Madrid-Barcelona Km, 33.6, 28871 Alcalá de Henares, Madrid (Spain)

    2015-01-15

    Contamination of urban and industrial soils with trace metals has been recognized as a major concern at local, regional and global levels due to their implication on human health. In this study, concentrations of aluminum (Al), arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb), tin (Sn), thallium (Tl), vanadium (V) and zinc (Zn) were determined in soil samples collected in Alcalá de Henares (Madrid, Spain) in order to evaluate the annual and seasonal variation in their levels. The results show that the soils of the industrial area have higher metals concentrations than the urban area. Principal component analysis (PCA) revealed that the two principal sources of trace metal contamination, especially Cd, Cu, Pb, and Zn in the urban soils of Alcalá can be attributed to traffic emissions, while As, Ni and Be primarily originated from industrial discharges. The seasonal variation analysis has revealed that the emission sources in the industrial area remain constant with time. However, in urban areas, both emissions and emission pathways significantly increase over time due to ongoing development. Currently, there is no hypothesis that explains the small seasonal fluctuations of trace metals in soils, since there are many factors affecting this. Owing to the fact that urban environments are becoming the human habitat, it would therefore be advisable to monitor metals and metalloids in urban soils because of the potential risks to human health. - Highlights: • Anthropogenic activities may affect the seasonal metal variation in Alcalá's soils. • Weather characteristics may also influence the seasonal metal variation in soils. • Alcalá's continual urban growth may have increased the levels of metals in its soils. • Metal variability in Alcalá's industrial soils might be dependent on their sources. • High soil metal content might make it difficult to identify temporal variation.

  12. Active layer and permafrost thermal regime in a patterned ground soil in Maritime Antarctica, and relationship with climate variability models.

    Science.gov (United States)

    Chaves, D A; Lyra, G B; Francelino, M R; Silva, Ldb; Thomazini, A; Schaefer, Cegr

    2017-04-15

    Permafrost and active layer studies are important to understand and predict regional climate changes. The objectives of this work were: i) to characterize the soil thermal regime (active layer thickness and permafrost formation) and its interannual variability and ii) to evaluate the influence of different climate variability modes to the observed soil thermal regime in a patterned ground soil in Maritime Antarctica. The study was carried out at Keller Peninsula, King George Island, Maritime Antarctica. Six soil temperatures probes were installed at different depths (10, 30 and 80cm) in the polygon center (Tc) and border (Tb) of a patterned ground soil. We applied cross-correlation analysis and standardized series were related to the Antarctic Oscillation Index (AAO). The estimated active layer thickness was approximately 0.75cm in the polygon border and 0.64cm in the center, indicating the presence of permafrost (within 80cm). Results indicate that summer and winter temperatures are becoming colder and warmer, respectively. Considering similar active layer thickness, the polygon border presented greater thawing days, resulting in greater vulnerability to warming, cooling faster than the center, due to its lower volumetric heat capacity (Cs). Cross-correlation analysis indicated statistically significant delay of 1day (at 10cm depth) in the polygon center, and 5days (at 80cm depth) for the thermal response between atmosphere and soil. Air temperature showed a delay of 5months with the climate variability models. The influence of southern winds from high latitudes, in the south facing slopes, favored freeze in the upper soil layers, and also contributed to keep permafrost closer to the surface. The observed cooling trend is linked to the regional climate variability modes influenced by atmospheric circulation, although longer monitoring period is required to reach a more precise scenario. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Influence of plant productivity over variability of soil respiration: a multi-scale approach

    Science.gov (United States)

    Curiel Yuste, J.

    2009-04-01

    general controlled by the seasonality of substrate supply by plants (via photosynthates translocation and/or litter) to soil. Although soil temperature and soil moisture exert a strong influence over the variation in SR, our results indicates that substrate supply by plant activity could exert a more important than previously expected role in the variability of soil respiration. 1. CREAF (Centre de Recerca Ecológica i Aplicacions Forestals), Unitat d'Ecofisiologia i Canvi Global CREAF-CEAB-CSIC, BELLATERRA (Barcelona), Spain (j.curiel@creaf.uab.es) 2. University of Antwerp (UA), Antwerp, Belgium (ivan.janssens@ua.ac.be) 3. Institute of Ecology, University of Innsbruck, Innsbruck, Austria (michael.bahn@uibk.ac.at) 4. UMR Ecologie et Ecophysiologie Forestières, Centre INRA de Nancy, France (longdoz@nancy.inra.fr) 5. ESPM, University of Calicornia at Berkeley, Berkeley, CA, US (baldocchi@nature.berkeley.edu) 6. The Woods Hole Research Center, Falmouth, USA (edavidson@whrc.org) 7. Max-Planck-Institute for Biogeochemistry, Jena, Germany (markus.reichstein@bgc-jena.mpg.de) 8. Institute of Systems Biology and Ecology, Academy of Sciences of the Czech Republic, Czech Republic (manuel@brno.cas.cz) 9. Università degli studi della Tuscia, Viterbo, Italy (arriga@unitus.it) 10. Laurence Berkeley lab, Berkeley, CA, USA (mstorn@lbl.gov) 11. Gembloux Agricultural University, Gembloux, Belgium (aubinet.m@fsagx.ac.be) 12. Fundacion CEAM(Centro de Estudios Ambientales del Mediterráneo), Valencia, Spain (arnaud@ceam.es) 13. Institute of Hydrology and Meteorology, Technische Universität Dresden, Pienner, Germany (gruenwald@forst.tu-dresden.de) 14. Department of Environmental Sciences, Second University of Naples, Caserta, Italy (ilaria.inglima@unina2.it) 15. CNRS-CEFE Montpellier, France (Laurent.MISSON@cefe.cnrs.fr) 16. Agenzia Provinciale per l'Ambiente, Bolzano, Italy (leonar@inwind.it) 17. University of Helsinki Department of Forest Ecology, Helsinki, Finland (jukka

  14. Spatial Variability of Near-surface Soil Moisture for Bioenergy Crops at the Great Lakes Bioenergy Research Center

    Science.gov (United States)

    van Dam, R. L.; Diker, K.; Bhardwaj, A. K.; Hamilton, S. K.

    2009-12-01

    We used time-lapse electrical resistivity imaging (ERI) to monitor spatial and temporal soil moisture variability below ten different potential bioenergy cropping systems at the Great Lakes Bioenergy Research Center’s sustainability research site in Michigan, U.S.A. These crops range from high-diversity, low-input grasses and poplars to low-diversity, high-input corn-soybean-canola rotations. We equipped the 28x40m vegetation plots with permanent 2D resistivity arrays, each consisting of 40 graphite electrodes at 30cm spacing. Other permanent equipment in each plot includes multi-depth temperature and time domain reflectometry (TDR) based moisture sensors, and two tension soil water samplers. The material at the site consists of coarse sandy glacial tills in which a soil with an approximately 50cm thick A-Bt horizon has developed. ERI data were collected using a dipole-dipole configuration every four weeks since early May 2009. After removal of bad points, the data were inverted and translated into 2D images of water content using lab-derived petrophysical relationships, including corrections for soil temperature and salinity. The results show significant seasonal variation within and between vegetation plots. We compare our results to high-temporal resolution point-based measurements of soil moisture from TDR probes and present statistical analysis of the variability of soil moisture within and between plots.

  15. [Effects of land use and environmental factors on the variability of soil quality indicators in hilly Loess Plateau region of China].

    Science.gov (United States)

    Xu, Ming-Xiang; Liu, Guo-Bin; Zhao, Yun-Ge

    2011-02-01

    Classical statistics methods were adopted to analyze the soil quality variability, its affecting factors, and affecting degree at a regional scale (700 km2) in the central part of hilly Loess Plateau region of China. There existed great differences in the variability of test soil quality indicators. Soil pH, structural coefficient, silt content, specific gravity, bulk density, total porosity, capillary porosity, and catalase activity were the indicators with weak variability; soil nutrients (N, P, and K) contents, CaCO3 content, cation exchange capacity (CEC), clay content, micro-aggregate mean mass diameter, aggregate mean mass diameter, water-stable aggregates, respiration rate, microbial quotient, invertase and phosphatase activities, respiratory quotient, and microbial carbon and nitrogen showed medium variation; while soil labile organic carbon and phosphorus contents, erosion-resistance, permeability coefficient, and urease activity were the indicators with strong variability. The variability of soil CaCO3, total P and K, CEC, texture, and specific gravity, etc. was correlated with topography and other environmental factors, while the variability of dynamic soil quality indicators, including soil organic matter content, nitrogen content, water-stable aggregates, permeability, microbial biomass carbon and nitrogen, enzyme activities, and respiration rate, was mainly correlated with land use type. Overall, land use pattern explained 97% of the variability of soil quality indicators in the region. It was suggested that in the evaluation of soil quality in hilly Loess Plateau region, land use type and environmental factors should be fully considered.

  16. Spatial variability of the topsoil organic carbon in the Moso bamboo forests of southern China in association with soil properties.

    Science.gov (United States)

    Zhang, Houxi; Zhuang, Shunyao; Qian, Haiyan; Wang, Feng; Ji, Haibao

    2015-01-01

    Understanding the spatial variability of soil organic carbon (SOC) must be enhanced to improve sampling design and to develop soil management strategies in terrestrial ecosystems. Moso bamboo (Phyllostachys pubescens Mazel ex Houz.) forests have a high SOC storage potential; however, they also vary significantly spatially. This study investigated the spatial variability of SOC (0-20 cm) in association with other soil properties and with spatial variables in the Moso bamboo forests of Jian'ou City, which is a typical bamboo hometown in China. 209 soil samples were collected from Moso bamboo stands and then analyzed for SOC, bulk density (BD), pH, cation exchange capacity (CEC), and gravel content (GC) based on spatial distribution. The spatial variability of SOC was then examined using geostatistics. A Kriging map was produced through ordinary interpolation and required sample numbers were calculated by classical and Kriging methods. An aggregated boosted tree (ABT) analysis was also conducted. A semivariogram analysis indicated that ln(SOC) was best fitted with an exponential model and that it exhibited moderate spatial dependence, with a nugget/sill ratio of 0.462. SOC was significantly and linearly correlated with BD (r = -0.373**), pH (r = -0.429**), GC (r = -0.163*), CEC (r = 0.263**), and elevation (r = 0.192**). Moreover, the Kriging method requires fewer samples than the classical method given an expected standard error level as per a variance analysis. ABT analysis indicated that the physicochemical variables of soil affected SOC variation more significantly than spatial variables did, thus suggesting that the SOC in Moso bamboo forests can be strongly influenced by management practices. Thus, this study provides valuable information in relation to sampling strategy and insight into the potential of adjustments in agronomic measure, such as in fertilization for Moso bamboo production.

  17. Spatial variability of the topsoil organic carbon in the Moso bamboo forests of southern China in association with soil properties.

    Directory of Open Access Journals (Sweden)

    Houxi Zhang

    Full Text Available Understanding the spatial variability of soil organic carbon (SOC must be enhanced to improve sampling design and to develop soil management strategies in terrestrial ecosystems. Moso bamboo (Phyllostachys pubescens Mazel ex Houz. forests have a high SOC storage potential; however, they also vary significantly spatially. This study investigated the spatial variability of SOC (0-20 cm in association with other soil properties and with spatial variables in the Moso bamboo forests of Jian'ou City, which is a typical bamboo hometown in China. 209 soil samples were collected from Moso bamboo stands and then analyzed for SOC, bulk density (BD, pH, cation exchange capacity (CEC, and gravel content (GC based on spatial distribution. The spatial variability of SOC was then examined using geostatistics. A Kriging map was produced through ordinary interpolation and required sample numbers were calculated by classical and Kriging methods. An aggregated boosted tree (ABT analysis was also conducted. A semivariogram analysis indicated that ln(SOC was best fitted with an exponential model and that it exhibited moderate spatial dependence, with a nugget/sill ratio of 0.462. SOC was significantly and linearly correlated with BD (r = -0.373**, pH (r = -0.429**, GC (r = -0.163*, CEC (r = 0.263**, and elevation (r = 0.192**. Moreover, the Kriging method requires fewer samples than the classical method given an expected standard error level as per a variance analysis. ABT analysis indicated that the physicochemical variables of soil affected SOC variation more significantly than spatial variables did, thus suggesting that the SOC in Moso bamboo forests can be strongly influenced by management practices. Thus, this study provides valuable information in relation to sampling strategy and insight into the potential of adjustments in agronomic measure, such as in fertilization for Moso bamboo production.

  18. Variability of Water Quality across Headwater Catchments with Distinct Soils and Hydrologic Systems in Central Missouri

    Science.gov (United States)

    Takhachhe, P.; Liu, F.; Lerch, R. N.; Yang, J.; Balakumar, S.

    2016-12-01

    Surface water and groundwater contamination by herbicides and fertilizers continues to be a major water quality problem in central Missouri. The purpose of this study was to examine spatial variability of water quality among three different headwater catchments - Goodwater Creek Experimental Watershed (GCEW) with claypan soils, Sulphur Creek Watershed (SCW) with deep loess soils, and Wet Glaize Creek Watershed (WGCW) with weathered forest soils and karst hydrology - to better understand hydrologic controls on contaminant transport. Samples were collected from February 2015 to June 2016 from streams, springs and groundwater and analyzed for major nutrients and herbicides. Mean nitrate concentrations in stream water were 3.6 (±4.0) ppm, 1.6 (±1.4) ppm and 3.4 (±0.17) ppm in GCEW, SCW and WGCW, respectively. Mean nitrate concentrations in groundwater were higher than those in stream water at GCEW and SCW, with 22.4 (±15.6) ppm in GCEW and 8.0 (±6.6) ppm in SCW. However, mean nitrate concentration in groundwater at WGCW (3.2±1.3 ppm) was similar to that in stream water, demonstrating the direct interaction of surface water and groundwater in karst hydrologic systems. Atrazine concentrations in stream water were higher than in groundwater at both GCEW and SCW. Mean atrazine concentrations in stream water were 2.4 (±4.6) ppb in GCEW and 1.5 ppb (±2.0) ppb in SCW. In groundwater, mean atrazine concentrations were 0.06 (±0.18) ppb in GCEW and 0.01(±0.01) ppb in SCW. The results indicated that surface water and groundwater interactions are much more important in understanding the controls on contaminant transport in the claypan and deep loess watersheds compared to the karst-dominated one. This approach provided insights into the differences in hydrologic controls on contaminant transport leading to better strategies for water quality management over various watersheds in central Missouri. Keywords; nutrients, herbicides, water quality

  19. Spatial variability of soil salinity at different scales in the mangrove rice agro-ecosystem in West Africa.

    NARCIS (Netherlands)

    Sylla, M.; Stein, A.; Breemen, van N.; Fresco, L.O.

    1995-01-01

    Spatial variability of soil salinity in coastal low lands results from a complex interaction of climate, river hydrology, topography and tidal flooding. The aim of this study was to determine the significant effects of these causal factors at different scales in the West African mangrove

  20. Temporal stability and variability of soil-water content in a gravel-mulched field in northwestern China

    Science.gov (United States)

    Zhao, Wenju; Cui, Zhen; Zhang, Jiyi; Jin, Jian

    2017-09-01

    Characterizing the spatiotemporal variability of soil-water content (SWC) is of paramount importance in many scientific fields and operational applications. We present a case study of the temporal stability and variability of SWC in a gravel-mulched field, a form of mulching that has been widely used by farmers on the loessial area of China for over 300 years, using Spearman correlation coefficients, frequency distributions and an index of temporal stability. SWC was measured weekly from May to August 2013 in the 0-10, 10-20, 20-30 and 30-50 cm layers. SWC was more variable in the surface soil, due to several environmental factors, and the variability gradually decreased with depth. A large sample size was needed for estimating the mean SWC of the field under dry conditions. High Spearman correlation coefficients between the SWCs measured on different sampling campaigns indicated a high temporal stability. The stability of the SWC spatial patterns over time and along the soil profile allowed us to identify a location representative of the field-mean SWC, with high coefficients of determination ranging between 0.8564 and 0.9325. The large-scale monitoring of SWC from few observations is thus feasible, which will aid the management of soil moisture in gravel-mulched fields in arid regions.

  1. Sensitivity analysis of tracer transport in variably saturated soils at USDA-ARS OPE3 field site

    Science.gov (United States)

    The objective of this study was to assess the effects of uncertainties in hydrologic and geochemical parameters on the results of simulations of the tracer transport in variably saturated soils at the USDA-ARS OPE3 field site. A tracer experiment with a pulse of KCL solution applied to an irrigatio...

  2. Variability of soil enzyme activities and vegetation succession following boreal forest surface soil transfer to an artificial hill

    Directory of Open Access Journals (Sweden)

    Maarit Niemi

    2014-08-01

    Full Text Available A landfill site in southern Finland was converted into urban green space by covering it with a layer of fresh forest humus transferred from nearby construction sites. The aim was to develop the 70 m high artificial hill into a recreational area with high biodiversity of flora and fauna. Forest humus was used as a source of organic matter, plant roots, seeds, soil fauna and microorganisms in order to enable rapid regeneration of diverse vegetation and soil biological functions. In this study we report the results of three years of monitoring of soil enzyme activity and plant species compositional patterns. Monthly soil samples were taken each year between June and September from four sites on the hill and from two standing reference forests using three replicate plots. Activities of 10 different enzymes, soil organic matter (SOM content, moisture, pH and temperature of the surface layer were monitored. Abundances of vascular plant species were surveyed on the same four hill sites between late May and early September, three times a season in 2004 and 2005. Although the addition of organic soil considerably increased soil enzyme activities (per dw, the activities at the covered hill sites were far lower than in the reference forests. Temporal changes and differences between sites were analysed in more detail per soil organic matter (SOM in order to reveal differences in the quality of SOM. All the sites had a characteristic enzyme activity pattern and two hill sites showed clear temporal changes. The enzyme activities in uncovered topsoil increased, whereas the activities at the covered Middle site decreased, when compared with other sites at the same time. The different trend between Middle and North sites in enzyme activities may reflect differences in humus material transferred to these sites, but difference in the succession of vegetation affects enzyme activities strongly. Middle yielded higher β-sitosterol content in 2004, as an indication

  3. Geostatistical modeling of the spatial variability and risk areas of southern root-knot nematodes in relation to soil properties.

    Science.gov (United States)

    Ortiz, B V; Perry, C; Goovaerts, P; Vellidis, G; Sullivan, D

    2010-05-01

    Identifying the spatial variability and risk areas for southern root-knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood] (RKN) is key for site-specific management (SSM) of cotton (Gossypium hirsutum L.) fields. The objectives of this study were to: (i) determine the soil properties that influence RKN occurrence at different scales; and (ii) delineate risk areas of RKN by indicator kriging. The study site was a cotton field located in the southeastern coastal plain region of the USA. Nested semivariograms indicated that RKN samples, collected from a 50×50 m grid, exhibited a local and regional scale of variation describing small and large clusters of RKN population density. Factorial kriging decomposed RKN and soil properties variability into different spatial components. Scale dependent correlations between RKN data showed that the areas with high RKN population remained stable though the growing season. RKN data were strongly correlated with slope (SL) at local scale and with apparent soil electrical conductivity deep (EC(a-d)) at both local and regional scales, which illustrate the potential of these soil physical properties as surrogate data for RKN population. The correlation between RKN data and soil chemical properties was soil texture mediated. Indicator kriging (IK) maps developed using either RKN, the relation between RKN and soil electrical conductivity or a combination of both, depicted the probability for RKN population to exceed the threshold of 100 second stage juveniles/100 cm(3) of soil. Incorporating EC(a-d) as soft data improved predictions favoring the reduction of the number of RKN observations required to map areas at risk for high RKN population.

  4. A Bézier-Spline-based Model for the Simulation of Hysteresis in Variably Saturated Soil

    Science.gov (United States)

    Cremer, Clemens; Peche, Aaron; Thiele, Luisa-Bianca; Graf, Thomas; Neuweiler, Insa

    2017-04-01

    Most transient variably saturated flow models neglect hysteresis in the p_c-S-relationship (Beven, 2012). Such models tend to inadequately represent matrix potential and saturation distribution. Thereby, when simulating flow and transport processes, fluid and solute fluxes might be overestimated (Russo et al., 1989). In this study, we present a simple, computationally efficient and easily applicable model that enables to adequately describe hysteresis in the p_c-S-relationship for variably saturated flow. This model can be seen as an extension to the existing play-type model (Beliaev and Hassanizadeh, 2001), where scanning curves are simplified as vertical lines between main imbibition and main drainage curve. In our model, we use continuous linear and Bézier-Spline-based functions. We show the successful validation of the model by numerically reproducing a physical experiment by Gillham, Klute and Heermann (1976) describing primary drainage and imbibition in a vertical soil column. With a deviation of 3%, the simple Bézier-Spline-based model performs significantly better that the play-type approach, which deviates by 30% from the experimental results. Finally, we discuss the realization of physical experiments in order to extend the model to secondary scanning curves and in order to determine scanning curve steepness. {Literature} Beven, K.J. (2012). Rainfall-Runoff-Modelling: The Primer. John Wiley and Sons. Russo, D., Jury, W. A., & Butters, G. L. (1989). Numerical analysis of solute transport during transient irrigation: 1. The effect of hysteresis and profile heterogeneity. Water Resources Research, 25(10), 2109-2118. https://doi.org/10.1029/WR025i010p02109. Beliaev, A.Y. & Hassanizadeh, S.M. (2001). A Theoretical Model of Hysteresis and Dynamic Effects in the Capillary Relation for Two-phase Flow in Porous Media. Transport in Porous Media 43: 487. doi:10.1023/A:1010736108256. Gillham, R., Klute, A., & Heermann, D. (1976). Hydraulic properties of a porous

  5. A new modelling approach for compacted clayey soils using specific water volume as a state variable

    OpenAIRE

    Abeyrathne, Wedumpuli Koralalage Arunodi Prabashini

    2017-01-01

    One of the key challenges of the present geotechnical engineering community is the accurate definition of unsaturated soil behaviour in routine engineering practice. This is because despite the remarkable progression of unsaturated soil mechanics as a branch of geotechnical engineering over the last few decades, the gap between unsaturated soils research and practice has widened significantly as the models to predict the soil behaviour have become more and more complex. Ther...

  6. effective hydraulic conductivity for a soil of variable pore size with ...

    African Journals Online (AJOL)

    eobe

    Two models were derived for the estimation of effective hydraulic conductivity (K models were derived for the estimation of effective hydraulic conductivity (Ke) of a soil layer based on exponential and inverse square variation of hydraulic conductivity with soil depth. Darcy's law was applied to a vertical soil stratum ...

  7. Searching for the right scale in catchment hydrology: the effect of soil spatial variability in simulated states and fluxes

    Science.gov (United States)

    Baroni, Gabriele; Zink, Matthias; Kumar, Rohini; Samaniego, Luis; Attinger, Sabine

    2017-04-01

    The advances in computer science and the availability of new detailed data-sets have led to a growing number of distributed hydrological models applied to finer and finer grid resolutions for larger and larger catchment areas. It was argued, however, that this trend does not necessarily guarantee better understanding of the hydrological processes or it is even not necessary for specific modelling applications. In the present study, this topic is further discussed in relation to the soil spatial heterogeneity and its effect on simulated hydrological state and fluxes. To this end, three methods are developed and used for the characterization of the soil heterogeneity at different spatial scales. The methods are applied at the soil map of the upper Neckar catchment (Germany), as example. The different soil realizations are assessed regarding their impact on simulated state and fluxes using the distributed hydrological model mHM. The results are analysed by aggregating the model outputs at different spatial scales based on the Representative Elementary Scale concept (RES) proposed by Refsgaard et al. (2016). The analysis is further extended in the present study by aggregating the model output also at different temporal scales. The results show that small scale soil variabilities are not relevant when the integrated hydrological responses are considered e.g., simulated streamflow or average soil moisture over sub-catchments. On the contrary, these small scale soil variabilities strongly affect locally simulated states and fluxes i.e., soil moisture and evapotranspiration simulated at the grid resolution. A clear trade-off is also detected by aggregating the model output by spatial and temporal scales. Despite the scale at which the soil variabilities are (or are not) relevant is not universal, the RES concept provides a simple and effective framework to quantify the predictive capability of distributed models and to identify the need for further model improvements e

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

    Science.gov (United States)

    Gorji, Taha; Sertel, Elif; Tanik, Aysegul

    2017-12-01

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

  9. Using scaling factors for evaluating spatial and temporal variability of soil hydraulic properties within one elevation transect

    Science.gov (United States)

    Nikodem, Antonín; Kodešová, Radka; Jakšík, Ondřej; Fér, Miroslav; Klement, Aleš

    2016-04-01

    This study was carried out in Southern Moravia, in the Czech Republic. The original soil unit in the wider area is a Haplic Chernozem developed on loess. The intensive agricultural exploitation in combination with terrain morphology has resulted in a highly diversified soil spatial pattern. Nowadays the original soil unit is preserved only on top of relatively flat parts, and is gradually transformed by water erosion up to Regosols on the steepest slopes, while colluvial soils are formed in terrain depressions and at toe slopes due to sedimentation of previously eroded material. Soils within this area has been intensively investigated during the last several years (e.g. Jakšík et al., 2015; Vašát et al., 2014, 2015a,b). Soil sampling (disturbed and undisturbed 100-cm3 soil samples) was performed at 5 points of one elevation transect in November 2010 (after wheat sowing) and August 2011 (after wheat harvest). Disturbed soil samples were used to determine basic soil properties (grain size distribution and organic carbon content etc.). 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. Scaling factors (alpha-h for pressure head, alpha-theta for soil water contents and alpha-k for hydraulic conductivities) were used here to express soil hydraulic properties variability. Evaluated scaling factors reflected position within the elevation transect as well as time of soil sampling. In general large values of alpha-h, lower values of alpha-k and similar values of alpha-theta were obtained in 2010 in comparison to values obtained in 2011, which indicates development of soil structure during the vegetation season. Jakšík, O., Kodešová, R., Kubiš, A., Stehlíková, I., Drábek, O., Kapička, A. (2015): Soil aggregate stability within morphologically diverse areas. Catena, 127, 287-299. Vašát, R., Kode

  10. Soils

    Science.gov (United States)

    Emily Moghaddas; Ken Hubbert

    2014-01-01

    When managing for resilient forests, each soil’s inherent capacity to resist and recover from changes in soil function should be evaluated relative to the anticipated extent and duration of soil disturbance. Application of several key principles will help ensure healthy, resilient soils: (1) minimize physical disturbance using guidelines tailored to specific soil types...

  11. The Spatial and Temporal Variability of Water Content in an Organic Soil in Dartmoor National Park, UK and its Relation to Microtopography and Organic Soil Horizon Depth.

    Science.gov (United States)

    Rogers, J.; Miles, H.; Berg, A.

    2009-05-01

    The water content of organic and mineral soils is an important parameter which links energy and mass balances at the earth's surface and as such is essential to understanding the spatial and temporal organization of many biological, biogeochemical, and hydrological processes. The characterization of surface water content in space and time is also important for the continued development of regional-scale and global circulation climate models and has large implications for agriculture and land-use planning. A field study was performed in Dartmoor National Park, Devon, UK in August 2008 for the purpose of exploring the predictive power of terrain indices on wetness patterns in an organic soil. Point samples were taken over the course of three days on two hill slopes of varying aspect in order to assess the influence of incident solar radiation on water storage. Additionally, the depth of the organic layer was estimated for each sample location and topographic information collected for the creation of a digital elevation model. A weak correlation between peat water content and organic soil layer depth was demonstrated and found to be strongest in shallow soils. Microtopography was found to influence the variability of soil moisture over the sampled area with surface roughness (measured by using residual elevation from the mean transect slope). Based on repeated observations over the sampling grids temporal persistence of water content patterns is evident and can be linked to terrain indices and depth of the organic layer.

  12. Spatial distribution of labile and protected fractions of soil organic matter as a combined effect of variable soil texture and forest tree species composition

    Science.gov (United States)

    Gruba, Piotr; Socha, Jarosław; Błońska, Ewa; Lasota, Jarosław

    2014-05-01

    In this investigations we focused on the effects of variable soil texture and forest species composition on: (1) stocks of soil organic carbon (SOC) in the organic horizon (O) and mineral soil (A and B horizons), and (2) content of carbon in physically separated fractions of samples from the A horizon: free light fraction (CfLF), occluded (inside aggregates) free light fraction (CoLF), and mineral associated fraction (CMA). Study area was located in the Swietokrzskie mountains, central Poland. The soils were derived from Triassic claystones and sandstones and Quaternary sandy deposits. The dominant forest species were Silver fir and European beech, with minor admixture of common hornbeam and Scots pine. We set up 275 plots in regular 200x200 m grid. Spatial dependence and correlations were analyzed using multiple regression and geostatistical tools: variogram and cross-variogram. The results demonstrated that the proportion between carbon stored in above ground tree biomass, soil organic horizon and mineral soil is roughly 10:5:5 (kg m-2). A key factor regulating retention of organic matter in soils was the content of fine fractions (FF). The content of FF positively affected the content of SOM in mineral soil and negatively the content of SOM accumulated in the organic horizon. Regarding the fraction of SOC in the A horizons, the content of FF had strong positive effect on the content of CMA (CMA [g kg-1]= 1.4 + 0.40 × FF[%], n=275, R2=0.70), weak positive influence on the CfLF, and no effect on CoLF. The content of labile fraction accumulated as the O horizon and CfLF fraction in the A horizon were negatively correlated. Results of statistical and geostatistical analysis suggest that the increasing share of beech and hornbeam had a positive effect on carbon stores in mineral soil and the opposite was true for the relationship between the FF content and carbon stores in the O horizon. Fir, in the other hand, positively influenced the content of carbon occluded

  13. Controls on the temporal and spatial variability of soil moisture in a mountainous landscape: the signature of snow and complex terrain

    Directory of Open Access Journals (Sweden)

    J. P. McNamara

    2009-07-01

    Full Text Available The controls on the spatial distribution of soil moisture include static and dynamic variables. The superposition of static and dynamic controls can lead to different soil moisture patterns for a given catchment during wetting, draining, and drying periods. These relationships can be further complicated in snow-dominated mountain regions where soil water input by precipitation is largely dictated by the spatial variability of snow accumulation and melt. In this study, we assess controls on spatial and temporal soil moisture variability in a small (0.02 km2, snow-dominated, semi-arid catchment by evaluating spatial correlations between soil moisture and site characteristics through different hydrologic seasons. We assess the relative importance of snow with respect to other catchment properties on the spatial variability of soil moisture and track the temporal persistence of those controls. Spatial distribution of snow, distance from divide, soil texture, and soil depth exerted significant control on the spatial variability of moisture content throughout most of the hydrologic year. These relationships were strongest during the wettest period and degraded during the dry period. As the catchment cycled through wet and dry periods, the relative spatial variability of soil moisture tended to remain unchanged. We suggest that the static properties in complex terrain (slope, aspect, soils impose first order controls on the spatial variability of snow and resulting soil moisture patterns, and that the interaction of dynamic (timing of water input and static influences propagate that relative constant spatial variability through most of the hydrologic year. The results demonstrate that snow exerts significant influence on how water is retained within mid-elevation semi-arid catchments and suggest that reductions in annual snowpacks associated with changing climate regimes may strongly influence spatial and temporal soil moisture patterns and

  14. Variable charge and electrical double layer of mineral-water interfaces: silver halides versus metal (hydr)oxides.

    Science.gov (United States)

    Hiemstra, Tjisse

    2012-11-06

    Classically, silver (Ag) halides have been used to understand thermodynamic principles of the charging process and the corresponding development of the electrical double layer (EDL). A mechanistic approach to the processes on the molecular level has not yet been carried out using advanced surface complexation modeling (SCM) as applied to metal (hydr)oxide interfaces. Ag halides and metal (hydr)oxides behave quite differently in some respect. The location of charge in the interface of Ag halides is not a priori obvious. For AgI(s), SCM indicates the separation of interfacial charge in which the smaller silver ions are apparently farther away from the surface than iodide. This charge separation can be understood from the surface structure of the relevant crystal faces. Charge separation with positive charge above the surface is due to monodentate surface complex formation of Ag(+) ions binding to I sites located at the surface. Negative surface charge is due to the desorption of Ag(+) ions out of the lattice. These processes can be described with the charge distribution (CD) model. The MO/DFT optimized geometry of the complex is used to estimate the value of the CD. SCM reveals the EDL structure of AgI(s), having two Stern layers in series. The inner Stern layer has a very low capacitance (C(1) = 0.15 ± 0.01 F/m(2)) in comparison to that of metal (hydr)oxides, and this can be attributed to the strong orientation of the (primary) water molecules on the local electrostatic field of the Ag(+) and I(-) ions of the surface (relative dielectric constant ε(r) ≈ 6). Depending on the extent of water ordering, mineral surfaces may in principle develop a second Stern layer. The corresponding capacitance (C(2)) will depend on the degree of water ordering that may decrease in the series AgI (C(2) = 0.57 F/m(2)), goethite (C(2) = 0.74 F/m(2)), and rutile (C(2) = ∞), as discussed. The charging principles of AgI minerals iodargyrite and miersite may also be applied to minerals

  15. Characterization of soils in terms of pedological variability under different physiography of Damodar command area (part, West Bengal, India

    Directory of Open Access Journals (Sweden)

    Ranjan Bera

    2015-12-01

    Full Text Available Five representative soil profiles occurring on four different physiography under subtropical environment of Damodar command area, India, were studied for soil pedological variability. Two way approaches were taken to evaluate the extent of profile development. Firstly different extractants were used to determine various forms of Fe and Al and their different ratios. Average contents of Fe and Al, extracted by different extracting reagents were found to be in descending order, as follows: Aldith > Aloxa > Alpyr and Fedith > Feoxa > Fepyr. Analysis of pyrophosphate (pyr, oxalate (oxa, and dithionate (dith extractable Fe and Al fractions indicated that with increasing soil age, the content of crystalline Fe and Al oxides increased at the expense of the poorly crystalline forms. The mean content of amorphous Fe and Al, crystalline Fe and Al, and their ratios estimated the degree of soil development. In the second part, elemental analysis was done, silica to sesquioxide ratio as well as ratio of alkali cations was measured and weathering index of each horizon was determined. The ratios and weathering indices indicated that except Madhpur soil series, all other soils were young and pedological development was still in progress in Damodar command area.

  16. Changes in Bacterial And Archaeal Community Structure And Functional Diversity Along a Geochemically Variable Soil Profile

    Energy Technology Data Exchange (ETDEWEB)

    Hansel, C.M.; Fendorf, S.; Jardine, P.M.; Francis, C.A.

    2009-05-18

    Spatial heterogeneity in physical, chemical, and biological properties of soils allows for the proliferation of diverse microbial communities. Factors influencing the structuring of microbial communities, including availability of nutrients and water, pH, and soil texture, can vary considerably with soil depth and within soil aggregates. Here we investigated changes in the microbial and functional communities within soil aggregates obtained along a soil profile spanning the surface, vadose zone, and saturated soil environments. The composition and diversity of microbial communities and specific functional groups involved in key pathways in the geochemical cycling of nitrogen, Fe, and sulfur were characterized using a coupled approach involving cultivation-independent analysis of both 16S rRNA (bacterial and archaeal) and functional genes (amoA and dsrAB) as well as cultivation-based analysis of Fe(III)-reducing organisms. Here we found that the microbial communities and putative ammonia-oxidizing and Fe(III)-reducing communities varied greatly along the soil profile, likely reflecting differences in carbon availability, water content, and pH. In particular, the Crenarchaeota 16S rRNA sequences are largely unique to each horizon, sharing a distribution and diversity similar to those of the putative (amoA-based) ammonia-oxidizing archaeal community. Anaerobic microenvironments within soil aggregates also appear to allow for both anaerobic- and aerobic-based metabolisms, further highlighting the complexity and spatial heterogeneity impacting microbial community structure and metabolic potential within soils.

  17. A multi-set charged system search for truss optimization with variables of different natures; element grouping

    National Research Council Canada - National Science Library

    Ali Kaveh; Ali Zolghadr

    2011-01-01

      Optimization problems may include variables of different natures. In structural optimization for example different variables representing cross-sectional, geometrical, topological and grouping properties of the structure may be present...

  18. Effect of variable soil texture, metal saturation of soil organic matter (SOM) and tree species composition on spatial distribution of SOM in forest soils in Poland.

    Science.gov (United States)

    Gruba, Piotr; Socha, Jarosław; Błońska, Ewa; Lasota, Jarosław

    2015-07-15

    In this study we investigated the effect of fine (ϕsoils, site moisture, metal (Al and Fe) of soil organic matter (SOM) and forest species composition on the spatial distribution of carbon (C) pools in forest soils at the landscape scale. We established 275 plots in regular 200×200m grid in a forested area of 14.4km(2). Fieldwork included soil sampling of the organic horizon, mineral topsoil and subsoil down to 40cm deep. We analysed the vertical and horizontal distribution of soil organic carbon (SOC) stocks, as well as the quantity of physically separated fractions including the free light (fLF), occluded light (oLF) and mineral associated fractions (MAF) in the mineral topsoil (A, AE) horizons. Distribution of C in soils was predominantly affected by the variation in the FF content. In soils richer in the FF more SOC was accumulated in mineral horizons and less in the organic horizons. Accumulation of SOC in mineral soil was also positively affected by the degree of saturation of SOM with Al and Fe. The increasing share of beech influenced the distribution of C stock in soil profiles by reducing the depth of O horizon and increasing C stored in mineral soil. The content of FF was positively correlated with the content of C in MAF and fLF fractions. The content of oLF and MAF fractions was also positively influenced by a higher degree of metal saturation, particularly Al. Our results confirmed that Al plays an important role in the stabilization of SOM inside aggregates (CoLF) and as in CMAF fractions. We also found a significant, positive effect of beech on the CfLF and fir on the CoLF content. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Influence of environmental variables on the structure and composition of soil bacterial communities in natural and constructed wetlands.

    Science.gov (United States)

    Arroyo, Paula; Sáenz de Miera, Luis E; Ansola, Gemma

    2015-02-15

    Bacteria are key players in wetland ecosystems, however many essential aspects regarding the ecology of wetland bacterial communities remain unknown. The present study characterizes soil bacterial communities from natural and constructed wetlands through the pyrosequencing of 16S rDNA genes in order to evaluate the influence of wetland variables on bacterial community composition and structure. The results show that the composition of soil bacterial communities was significantly associated with the wetland type (natural or constructed wetland), the type of environment (lagoon, Typha or Salix) and three continuous parameters (SOM, COD and TKN). However, no clear associations were observed with soil pH. Bacterial diversity values were significantly lower in the constructed wetland with the highest inlet nutrient concentrations. The abundances of particular metabolic groups were also related to wetland characteristics. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Soil organic carbon sequestration in upland soils of northern China under variable fertilizer management and climate change scenarios

    Science.gov (United States)

    Jiang, Guiying; Xu, Minggang; He, Xinhua; Zhang, Wenju; Huang, Shaomin; Yang, Xueyun; Liu, Hua; Peng, Chang; Shirato, Yasuhito; Iizumi, Toshichika; Wang, Jinzhou; Murphy, Daniel V.

    2014-03-01

    We determined the historical change in soil organic carbon (SOC) stocks from long-term field trials that represent major soil types and climatic conditions of northern China. Soil carbon and general circulation models were validated using these field trial data sets. We then applied these models to predict future change in SOC stocks to 2100 using two net primary production (NPP) scenarios (i.e., current NPP or 1% year-1 NPP increase). The conversion rate of plant residues to SOC was higher in single-cropping sites than in double-cropping sites. The prediction of future SOC sequestration potential indicated that these soils will be a net source of carbon dioxide (CO2) under no fertilizer inputs. Even when inorganic nutrients were applied, the additional carbon input from increased plant residues could not meet the depletion of SOC in parts of northern China. Manure or straw application could however improve the SOC sequestration potential at all sites. The SOC sequestration potential in northern China was estimated to be -4.3 to 18.2 t C ha-1 by 2100. The effect of projected climate change on the annual rate of SOC change did not differ significantly between climate scenarios. The average annual rate of SOC change under current and increased NPP scenarios (at 850 ppm CO2) was approximately 0.136 t C ha-1 yr-1 in northern China. These findings highlight the need to maintain, and where possible increase, organic carbon inputs into these farming systems which are rapidly becoming inorganic fertilizer intensive.

  1. Determinação do ponto de carga zero em solos Determination of the zero point of charge in soils

    Directory of Open Access Journals (Sweden)

    Bernardo van Raij

    1973-01-01

    Full Text Available São apresentados os fundamentos e dois métodos de determinação do ponto de carga zero (PCZ em solos. Por um dos métodos o PCZ foi determinado como sendo o pH do ponto de cruzamento de curvas de titulação dos solos em soluções de NaCl 1; 0.1; 0 01; c 0,001N. Pelo outro método o PCZ foi determinado por extrapolação ou interpolação da carga líquida dos solos, determinada por retenção de íons em soluções de NaCl 0,2N, CaCl2 0,01N e MgSO4 0,01N, ao valor de pH em que a carga líquida era nula.The zero point of charge (ZPC of soils was determined by the crossing point of acid-base potenciometric titration curves in different concentrations of NaCl. Alternatively, the ZPC was found by extrapolating or interpolating the net electric charge of soils, determined by direct adsorption of ions from solution of NaCl, CaCl2 and MgSO4, to the pH of charge zero.

  2. Influence of soil C stocks and interannual climatic variability on the CO2 and CH4 exchange of maize cultivated on mineral and organic soils in NE Germany

    Science.gov (United States)

    Pohl, Madlen; Hagemann, Ulrike; Hoffmann, Mathias; Giebels, Michael; Albiac-Borraz, Elisa; Sommer, Michael; Augustin, Jürgen

    2014-05-01

    Due to its glacially influenced genesis and land use history, the soils of the Great Plain Region of NE-Germany show large differences in groundwater levels and soil carbon (C) stocks over short distances. Although generally featuring a rather dry climate, trace gas exchange at individual sites may be influenced by i) interannual climatic variability, particularly with respect to precipitation; as well as by ii) variability of soil C stocks. However, it is still unclear how these factors affect fluxes of CO2 and CH4, and if there is any positive or negative feedback on the C source or sink function of different soil types. We present measured and modeled CO2 and CH4 fluxes of minerally fertilized grain maize for three sites located near Paulinenaue, within the so-called Rhin-Havelluch, a shallow and drained paludification mire complex in NE Germany. The sites are characterized by a distinct gradient of 0-1 m soil organic C stocks: i) Arenosol (AR: mineral soil/distant groundwater; 8 000 g C m-2), ii) Gleysol (GL: organic soil/groundwater-dependent; 35 000 g C m-2), and iii) Histosol (HS: organic soil/near groundwater; 45 000 g C m-2). CO2 flux measurements of ecosystem respiration (Reco), net ecosystem exchange (NEE) and gross primary production (GPP; calculated as difference between NEE and Reco) were conducted every four weeks using a flow-through non-steady-state closed chamber system. Measurement gaps of Reco and NEE were filled by using temperature or radiation-based models, respectively. CH4 fluxes were measured bi-weekly using a static closed chamber system with interval sampling, with gap filling via linear interpolation. Cumulated fluxes of CO2-C (Reco, GPP, NEE) and CH4-C were calculated for a period of four consecutive years (2007-2010). The intensity of CO2-C fluxes increased with growing soil organic C stocks (AR years 2008-2010 for Reco ranged between 1 500 g C m-2 and 2 000 g C m-2; annual GPP fluxes ranged from -1 400 g C m-2 to -2 300 g C m-2. NEE

  3. Reference Evapotranspiration Retrievals from a Mesoscale Model Based Weather Variables for Soil Moisture Deficit Estimation

    Directory of Open Access Journals (Sweden)

    Prashant K. Srivastava

    2017-10-01

    Full Text Available Reference Evapotranspiration (ETo and soil moisture deficit (SMD are vital for understanding the hydrological processes, particularly in the context of sustainable water use efficiency in the globe. Precise estimation of ETo and SMD are required for developing appropriate forecasting systems, in hydrological modeling and also in precision agriculture. In this study, the surface temperature downscaled from Weather Research and Forecasting (WRF model is used to estimate ETo using the boundary conditions that are provided by the European Center for Medium Range Weather Forecast (ECMWF. In order to understand the performance, the Hamon’s method is employed to estimate the ETo using the temperature from meteorological station and WRF derived variables. After estimating the ETo, a range of linear and non-linear models is utilized to retrieve SMD. The performance statistics such as RMSE, %Bias, and Nash Sutcliffe Efficiency (NSE indicates that the exponential model (RMSE = 0.226; %Bias = −0.077; NSE = 0.616 is efficient for SMD estimation by using the Observed ETo in comparison to the other linear and non-linear models (RMSE range = 0.019–0.667; %Bias range = 2.821–6.894; NSE = 0.013–0.419 used in this study. On the other hand, in the scenario where SMD is estimated using WRF downscaled meteorological variables based ETo, the linear model is found promising (RMSE = 0.017; %Bias = 5.280; NSE = 0.448 as compared to the non-linear models (RMSE range = 0.022–0.707; %Bias range = −0.207–−6.088; NSE range = 0.013–0.149. Our findings also suggest that all the models are performing better during the growing season (RMSE range = 0.024–0.025; %Bias range = −4.982–−3.431; r = 0.245–0.281 than the non−growing season (RMSE range = 0.011–0.12; %Bias range = 33.073–32.701; r = 0.161–0.244 for SMD estimation.

  4. Toxicity screening of soils from different mine areas—A contribution to track the sensitivity and variability of Arthrobacter globiformis assay

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Catarina R., E-mail: crmarques@ua.pt [Departamento de Biologia and CESAM (Centro de Estudos do Ambiente e do Mar), Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Caetano, Ana L. [Departamento de Biologia and CESAM (Centro de Estudos do Ambiente e do Mar), Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Haller, Andreas [ECT Oekotoxikologie GmbH, Böttgerstraße 2–14, D-65439 Flörsheim a. M. (Germany); Gonçalves, Fernando [Departamento de Biologia and CESAM (Centro de Estudos do Ambiente e do Mar), Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Pereira, Ruth [Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto (Portugal); Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), Universidade do Porto, Rua dos Bragas 289, P 4050-123 Porto (Portugal); Römbke, Jörg [ECT Oekotoxikologie GmbH, Böttgerstraße 2–14, D-65439 Flörsheim a. M. (Germany)

    2014-06-01

    Highlights: • The assay gave rapid and feasible discrimination of toxic soils to A. globiformis. • Sensitive and low variability response to soils from different regions. • Soil properties may interfere with metal toxicity and fluorescence measurements. • Proposal of a toxicity threshold for the contact assay regarding soils. • A. globiformis assay should be included in the Tier I of risk assessment frameworks. - Abstract: This study used the Arthrobacter globiformis solid-contact test for assessing the quality of soils collected in areas subjected to past and present mine activities in Europe (uranium mine, Portugal) and North Africa (phosphogypsum pile, Tunisia; iron mine, Morocco). As to discriminate the influence of soils natural variability from the effect of contaminants, toxicity thresholds were derived for this test, based on the dataset of each study area. Furthermore, the test sensitivity and variability was also evaluated. As a result, soils that inhibited A. globiformis dehydrogenase activity above 45% or 50% relatively to the control, were considered to be toxic. Despite the soil metal content determined, the properties of soils seemed to influence dehydrogenase activity. Overall, the contact test provided a coherent outcome comparing to other more time-consuming and effort-demanding ecotoxicological assays. Our results strengthened the feasibility and ecological relevance of this assay, which variability was quite reduced hence suggesting its potential integration within the test battery of tier 1 of soil risk assessment schemes.

  5. The water budget of heterogeneous areas : impact of soil and rainfall variability

    NARCIS (Netherlands)

    Kim, C.P.

    1995-01-01

    In this thesis the heterogeneity of the soil water budget components is investigated. Heterogeneity of soil hydraulic properties and rainfall rate are taken into account by using stochastic methods. The importance of lateral groundwater flow in causing heterogeneity of the water budget

  6. Functional interpretation of representative soil spatial-temporal variability at the Central region of European territory of Russia

    Science.gov (United States)

    Vasenev, I.

    2012-04-01

    The essential spatial and temporal variability is mutual feature for most natural and man-changed soils at the Central region of European territory of Russia. The original spatial heterogeneity of forest and forest-steppe soils has been further complicated by a specific land-use history and different-direction soil successions due to environmental changes and human impacts. For demand-driven land-use planning and decision making the quantitative analysis, modeling and functional-ecological interpretation of representative soil cover patterns spatial variability is an important and challenging task that receives increasing attention from scientific society, private companies, governmental and environmental bodies. On basis of long-term different-scale soil mapping, key plot investigation, land quality and land-use evaluation, soil forming and degradation processes modeling, functional-ecological typology of the zonal set of elementary soil cover patterns (ESCP) has been done in representative natural and man transformed ecosystems of the forest, forest-steppe and steppe zones at the Central region of European territory of Russia (ETR). The validation and ranging of the limiting factors of functional quality and ecological state have been made for dominating and most dynamical components of ESCP regional-typological forms - with application of local GIS, traditional regression kriging and correlation tree models. Development, zonal-regional differentiation and verification of the basic set of criteria and algorithms for logically formalized distinguishing of the most "stable" & "hot" areas in soil cover patterns make it possible for quantitative assessment of dominating in them elementary landscape, soil-forming and degradation processes. The received data essentially expand known ranges of the soil forming processes (SFP) rate «in situ». In case of mature forests mutual for them the windthrow impacts and lateral processes make SFPs more active and complex both in

  7. Geostatistical modeling of the spatial variability and risk areas of southern root-knot nematodes in relation to soil properties

    OpenAIRE

    Ortiz, B.V.; Perry, C; Goovaerts, P.; Vellidis, G.; Sullivan, D.

    2010-01-01

    Identifying the spatial variability and risk areas for southern root-knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood] (RKN) is key for site-specific management (SSM) of cotton (Gossypium hirsutum L.) fields. The objectives of this study were to: (i) determine the soil properties that influence RKN occurrence at different scales; and (ii) delineate risk areas of RKN by indicator kriging. The study site was a cotton field located in the southeastern coastal plain region of the US...

  8. Spatial variability of soil water content in the covered catchment at Gårdsjön, Sweden

    Science.gov (United States)

    Nyberg, Lars

    1996-01-01

    The spatial variability of soil water content was investigated for a 6300 m2 covered catchment on the Swedish west coast. The catchment podzol soil is developed in a sandy - silty till with a mean depth of 43 cm and the dominant vegetation is Norway spruce. The acid precipitation is removed by a plastic roof and replaced with lake water irrigated under the tree canopies. On two occasions, in April and May 1993, TDR measurements were made at 57-73 points in the catchment using 15 and 30 cm long vertically installed probes. The water content pattern at the two dates, which occurred during a relatively dry period, were similar. The range of water content was large, from 5 to 60%. In May 1993 measurements also were made in areas of 10 × 10 m, 1 × 1 m and 0·2 × 0·2 m. The range and standard deviation for the 10 × 10 m area, which apart from a small-scale variability in soil hydraulic properties and fine root distribution also had a heterogeneous micro- and macro-topography, was similar to the range and standard deviation for the catchment. The 1 × 1 m and 0·2 × 0·2 m areas had considerably lower variability. Semi-variogram models for the water content had a range of influence of about 20 m. If data were paired in the east--west direction the semi-variance reflected the topography of the central valley and had a maximum for data pairs with internal distances of 20-40 m. The correlation between soil water content and topographic index, especially when averaged for the eight topographically homogeneous subareas, indicated the macro-topography as the cause of a large part of the water content variability.

  9. Charged amino acid variability related to N-glyco -sylation and epitopes in A/H3N2 influenza: Hem -agglutinin and neuraminidase.

    Science.gov (United States)

    Huang, Zhong-Zhou; Yu, Liang; Huang, Ping; Liang, Li-Jun; Guo, Qing

    2017-01-01

    The A/H3N2 influenza viruses circulated in humans have been shown to undergo antigenic drift, a process in which amino acid mutations result from nucleotide substitutions. There are few reports regarding the charged amino acid mutations. The purpose of this paper is to explore the relations between charged amino acids, N-glycosylation and epitopes in hemagglutinin (HA) and neuraminidase (NA). A total of 700 HA genes (691 NA genes) of A/H3N2 viruses were chronologically analyzed for the mutational variants in amino acid features, N-glycosylation sites and epitopes since its emergence in 1968. It was found that both the number of HA N-glycosylation sites and the electric charge of HA increased gradually up to 2016. The charges of HA and HA1 increased respectively 1.54-fold (+7.0 /+17.8) and 1.08-fold (+8.0/+16.6) and the number of NGS in nearly doubled (7/12). As great diversities occurred in 1990s, involving Epitope A, B and D mutations, the charged amino acids in Epitopes A, B, C and D in HA1 mutated at a high frequency in global circulating strains last decade. The charged amino acid mutations in Epitopes A (T135K) has shown high mutability in strains near years, resulting in a decrease of NGT135-135. Both K158N and K160T not only involved mutations charged in epitope B, but also caused a gain of NYT158-160. Epitope B and its adjacent N-glycosylation site NYT158-160 mutated more frequently, which might be under greater immune pressure than the rest. The charged amino acid mutations in A/H3N2 Influenza play a significant role in virus evolution, which might cause an important public health issue. Variability related to both the epitopes (A and B) and N-glycosylation is beneficial for understanding the evolutionary mechanisms, disease pathogenesis and vaccine research.

  10. Landscape and Seasonal Variability in CO2 Efflux from Soil and Water Surfaces in the Northern Pantanal

    Science.gov (United States)

    Couto, E. G.; Pinto-Jr, O. B.; Lathuilliere, M. J.; Dalmagro, H. J.; Johnson, M. S.

    2014-12-01

    The Pantanal is one of the largest wetlands in the world, with an area of 150,000 km2. It extends over three countries (Brazil, Paraguay and Bolivia) with 80% located in the Brazilian states of Mato Grosso and Mato Grosso do Sul. Ecosystems in the Northern Pantanal rely on a seasonal flood pulse in phase with the wet season, which inundates grasslands and forests between January and May. This pulse results in an important change in local biogeochemistry. Inundation saturates the Pantanal's soils with changes in the balance of carbon dioxide and other greenhouse gases. This study summarize the main CO2 effluxes measured from a variety of landscape in the Northern Pantanal during dry and wet seasons, fully or partially inundated soils, as part of Project 2.01 of the Brazilian Institute for Science and Technology in Wetlands (Monitoring aquatic carbon fluxes and water quality). Using a network of dataloggers installed in 4 environments, we have been modeling soil CO2 efflux on a half hourly basis through a combination of infrared gas analyzers measurements and laboratory soil physical parameter estimates. The selected environments presented unique biogeochemical behavior as they relate to inundation and soil type. So far, we have estimated average CO2 efflux in 3 environments with mean values of 3.53 µmol m-2 s-1 (soil CO2 efflux for the "Carrapatal" tree island), 3.41 µmol m-2 s-1 (soil CO2 efflux for the "Baia das Pedras" tree island), and 1.79 µmol m-2 s-1 (aquatic CO2 evasion from the water surface of the "Cambarazal" flooded forest). More measurements are currently underway to complete the landscape variability in CO2 effluxes in the Northern Pantanal.

  11. State-space approach to evaluate spatial variability of field measured soil water status along a line transect in a volcanic-vesuvian soil

    Directory of Open Access Journals (Sweden)

    A. Comegna

    2010-12-01

    Full Text Available Unsaturated hydraulic properties and their spatial variability today are analyzed in order to use properly mathematical models developed to simulate flow of the water and solute movement at the field-scale soils. Many studies have shown that observations of soil hydraulic properties should not be considered purely random, given that they possess a structure which may be described by means of stochastic processes. The techniques used for analyzing such a structure have essentially been based either on the theory of regionalized variables or to a lesser extent, on the analysis of time series. This work attempts to use the time-series approach mentioned above by means of a study of pressure head h and water content θ which characterize soil water status, in the space-time domain. The data of the analyses were recorded in the open field during a controlled drainage process, evaporation being prevented, along a 50 m transect in a volcanic Vesuvian soil. The isotropic hypothesis is empirical proved and then the autocorrelation ACF and the partial autocorrelation functions PACF were used to identify and estimate the ARMA(1,1 statistical model for the analyzed series and the AR(1 for the extracted signal. Relations with a state-space model are investigated, and a bivariate AR(1 model fitted. The simultaneous relations between θ and h are considered and estimated. The results are of value for sampling strategies and they should incite to a larger use of time and space series analysis.

  12. Vegetation-induced spatial variability of soil redox properties in wetlands

    Science.gov (United States)

    Szalai, Zoltán; Jakab, Gergely; Kiss, Klaudia; Ringer, Marianna; Balázs, Réka; Zacháry, Dóra; Horváth Szabó, Kata; Perényi, Katalin

    2016-04-01

    Vegetation induced land patches may result spatial pattern of on soil Eh and pH. These spatial pattern are mainly emerged by differences of aeration and exudation of assimilates. Present paper focuses on vertical extent and temporal dynamics of these patterns in wetlands. Two study sites were selected: 1. a plain wetland on calcareous sandy parent material (Ceglédbercel, Danube-Tisza Interfluve, Hungary); 2. headwater wetland with calcareous loamy parent material (Bátaapáti, Hungary). Two vegetation patches were studied in site 1: sedgy (dominated by Carex riparia) and reedy (dominated by Phragmites australis). Three patches were studied in site2: sedgy1 (dominated by C vulpina), sedgy 2 (C. riparia); nettle-horsetail (Urtica dioica and Equisetum arvense). Boundaries between patches were studied separately. Soil redox, pH and temperature studied by automated remote controlled instruments. Three digital sensors (Ponsell) were installed in each locations: 20cm and 40cm sensors represent the solum and 100 cm sensor monitors the subsoil). Groundwater wells were installed near to triplets for soil water sampling. Soil Eh, pH and temperature values were recorded in each 10 minutes. Soil water sampling for iron and DOC were carried out during saturated periods. Spatial pattern of soil Eh is clearly caused by vegetation. We measured significant differences between Eh values of the studied patches in the solum. We did not find this kinds horizontal differences in the subsoil. Boundaries of the patches usually had more reductive soil environment than the core areas. We have found temporal dynamics of the spatial redox pattern. Differences were not so well expressed during wintertime. These spatial patterns had influence on the DOC and iron content of porewater, as well. Highest temporal dynamics of soil redox properties and porewater iron could be found in the boundaries. These observations refer to importance patchiness of vegetation on soil chemical properties in

  13. Measurements of Dielectric Properties of Mars Analog Soils with Variable Temperature and Moisture Content

    Science.gov (United States)

    Cereti, A.; Mellon, M. T.; Sizemore, H. G.; Phillips, R. J.

    2009-03-01

    We performed impedance spectroscopy of various martian analog soils, with varying temperature and moisture content, to investigate how the complex dielectric permittivity depends on these factors, as this parameter can strongly affect radar signals propagation.

  14. Transport properties and pore-network structure in variably-saturated Sphagnum peat soil

    DEFF Research Database (Denmark)

    Hamamoto, Shoichiro; Dissanayaka, Shiromi Himalika; Kawamoto, K.

    2016-01-01

    ) of layers in peat soil from two profiles were measured under different moisture conditions. A two-region Archie's Law (2RAL)-type model was applied successfully to the four properties; the reference point was taken at -9.8kPa of soil-water matric potential where volume shrinkage typically started to occur...... a need for specific hydraulic functions for peat soil. The 2RAL model for Dg agreed well with measured data, and performed better than existing unimodal models. To facilitate use of the 2RAL for Dg, we developed a simple predictive expression for Dg at the reference point. The pore-network tortuosity......Gas and water transport in peat soil are of increasing interest because of their potentially large environmental and climatic effects under different types of land use. In this research, the water retention curve (WRC), gas diffusion coefficient (Dg) and air and water permeabilities (ka and kw...

  15. Tracking animal movement by comparing trace element signatures in claws to spatial variability of elements in soils.

    Science.gov (United States)

    Ethier, Danielle M; Kyle, Christopher J; Nocera, Joseph J

    2014-01-15

    Biogeochemical markers in ecology have provided a useful means for indicating geographic origin and movement patterns of species on various temporal and spatial scales. We used trace element analysis to resolve spatial and habitat-specific environmental gradients in elemental distributions that could be used to infer geographic origin and habitat association in a model terrestrial carnivore: American badger (Taxidea taxus jacksoni). To accomplish this, we generated element base-maps using spatial principal component analysis, and assessed habitat-specific signatures using multivariate statistics from soil element concentrations in southwestern Ontario, Canada. Using canonical correlation analysis (CCA) we also test whether element variability in the claw keratin of a terrestrial carnivore could be explained by the chemical variability in the soils of the local environment. Results demonstrated that trace element signatures in soils vary locally with land use practices and soil texture type and broadly with the underlying geology. CCA results suggest that chemical profiles in claws can be linked to the surrounding chemical environment, providing evidence that geographic patterns in mammalian movement can be discerned on the basis of claw chemistry. From this, we conclude that geographic assignment of individuals based on element profiles in their tissues and referenced against soil elemental distributions would be coarse (at a spatial scale of 100-1000 km, depending on the chemical heterogeneity of the landscape), but could be used to assess origin of highly mobile animals or habitat association of individuals. Compared to stable isotope analysis, the assessment of trace elements can provide a much greater level of detail in backcasting animal movement pathways. © 2013. Published by Elsevier B.V. All rights reserved.

  16. A probabilistic analysis of the dynamic response of monopile foundations: Soil variability and its consequences

    DEFF Research Database (Denmark)

    Damgaard, M.; Andersen, L.V.; Ibsen, L.B.

    2015-01-01

    -analytical impedance functions of a monopile embedded in a stochastic linear viscoelastic soil layer, fully coupled aero-hydro-elastic simulations are conducted in the nonlinear multi-body code Hawc2. The probabilistic analysis accounts for the uncertainty of soil properties (e.g. damping and stiffness) and relies...... properties. Lognormal and Gumbel distributed modal damping and accumulated side-side fatigue damage equivalent moments with a coefficient of variation of 30% and 8%, respectively, are observed....

  17. Spatio-temporal effects of soil and bedrock variability on grapevine water status in hillslope vineyards.

    Science.gov (United States)

    Brillante, Luca; Bois, Benjamin; Mathieu, Olivier; Leveque, Jean

    2014-05-01

    Hillslope vineyards show various and complex water dynamics between soil and plants, and in order to gain further insight into this phenomenon, 8 grapevine plots were monitored during three vintages, from 2010 to 2013, on Corton Hill, Burgundy, France. Plots were distributed along a topolithosequence from 330 to 270 metres a.s.l. Grapevine water status was monitored weekly by surveying water potential, and, at the end of the season, by the use of the δ13C analysis of grape juice. Soil profile of each plot was described and analysed (soil texture, gravel content, organic carbon, total nitrogen, pH, CEC). Soil volumetric humidity was measured weekly, using TDR probes. A pedotransfer function was developed to transform Electrical Resistivity Imaging (ERI) into soil volume wetness and therefore to spatialise and observe variation in the Fraction of Transpirable Soil Water (FTSW). During the three years of monitoring, grapevines experienced great variation in water status, which ranged from low to considerable water deficit (as expressed by pre-dawn leaf water potential and δ13C analysis of grape juice). With ERI imaging, it was possible to observe differences in water absorption pattern by roots, in different soils, and at different depth. In addition, significant differences were observed in grapevine water status in relation to variations in the physical characteristics of the terroir along the hillslope (i.e. the geo-pedological context, the elevation etc.). Grapevine water behaviour and plant-soil water relationships on the hillslope of Corton Hill have been extensively characterised in this study by ultimate technologies, allowing to present this terroir as a very interesting example for future generalisation and modelling of the hillslope vineyard water dynamics.

  18. Topographic variability and the influence of soil erosion on the carbon cycle

    Science.gov (United States)

    Dialynas, Yannis G.; Bastola, Satish; Bras, Rafael L.; Billings, Sharon A.; Markewitz, Daniel; Richter, Daniel deB.

    2016-05-01

    Soil erosion, particularly that caused by agriculture, is closely linked to the global carbon (C) cycle. There is a wide range of contrasting global estimates of how erosion alters soil-atmosphere C exchange. This can be partly attributed to limited understanding of how geomorphology, topography, and management practices affect erosion and oxidation of soil organic C (SOC). This work presents a physically based approach that stresses the heterogeneity at fine spatial scales of SOC erosion, SOC burial, and associated soil-atmosphere C fluxes. The Holcombe's Branch watershed, part of the Calhoun Critical Zone Observatory in South Carolina, USA, is the case study used. The site has experienced some of the most serious agricultural soil erosion in North America. We use SOC content measurements from contrasting soil profiles and estimates of SOC oxidation rates at multiple soil depths. The methodology was implemented in the tRIBS-ECO (Triangulated Irregular Network-based Real-time Integrated Basin Simulator-Erosion and Carbon Oxidation), a spatially and depth-explicit model of SOC dynamics built within an existing coupled physically based hydro-geomorphic model. According to observations from multiple soil profiles, about 32% of the original SOC content has been eroded in the study area. The results indicate that C erosion and its replacement exhibit significant topographic variation at relatively small scales (tens of meters). The episodic representation of SOC erosion reproduces the history of SOC erosion better than models that use an assumption of constant erosion in space and time. The net atmospheric C exchange at the study site is estimated to range from a maximum source of 14.5 g m-2 yr-1 to a maximum sink of -18.2 g m-2 yr-1. The small-scale complexity of C erosion and burial driven by topography exerts a strong control on the landscape's capacity to serve as a C source or a sink.

  19. Do climate and soil influence phenotypic variability in leaf litter, microbial decomposition and shredder consumption?

    Science.gov (United States)

    Graça, M A S; Poquet, J M

    2014-03-01

    We tested the hypothesis that water stress and soil nutrient availability drive leaf-litter quality for decomposers and detritivores by relating chemical and physical leaf-litter properties and decomposability of Alnus glutinosa and Quercus robur, sampled together with edaphic parameters, across wide European climatic gradients. By regressing principal components analysis of leaf traits [N, P, condensed tannins, lignin, specific leaf area (SLA)] against environmental and soil parameters, we found that: (1) In Q. robur the condensed tannin and lignin contents increased and SLA decreased with precipitation, annual range of temperature, and soil N content, whereas leaf P increased with soil P and temperature; (2) In A. glutinosa leaves N, P, and SLA decreased and condensed tannins increased with temperature, annual range of temperature, and decreasing soil P. On the other hand, leaf P and condensed tannins increased and SLA decreased with minimum annual precipitation and towards sites with low temperature. We selected contrasting leaves in terms of quality to test decomposition and invertebrate consumption. There were intraspecific differences in microbial decomposition rates (field, Q. robur) and consumption by shredders (laboratory, A. glutinosa). We conclude that decomposition rates across ecosystems could be partially governed by climate and soil properties, affecting litter quality and therefore decomposers and detritivores. Under scenarios of global warming and increased nutrients, these results suggest we can expect species-specific changes in leaf-litter properties most likely resulting in slow decomposition with increased variance in temperatures and accelerated decomposition with P increase.

  20. Role of Micro-Topographic Variability on the Distribution of Inorganic Soil-Nitrogen Age in Intensively Managed Landscape

    Science.gov (United States)

    Woo, Dong K.; Kumar, Praveen

    2017-10-01

    How does the variability of topography structure the spatial heterogeneity of nutrient dynamics? In particular, what role does micro-topographic depression play in the spatial and temporal dynamics of nitrate, ammonia, and ammonium? We explore these questions using the 3-D simulation of their joint dynamics of concentration and age. To explicitly resolve micro-topographic variability and its control on moisture, vegetation, and carbon-nitrogen dynamics, we use a high-resolution LiDAR data over an agricultural site under a corn-soybean rotation in the Intensively Managed landscapes Critical Zone Observatory in the U.S. Midwest. We utilize a hybrid CPU-GPU parallel computing architecture to reduce the computational cost associated with such high-resolution simulations. Our results show that in areas that present closed topographic depressions, relatively lower nitrate concentration and age are observed compared to elsewhere. The periodic ponding in depressions increases the downward flux of water that carries more dissolved nitrate to the deeper soil layer. However, the variability in the depressions is relatively higher as a result of the episodic ponding pattern. When aggregate efflux from the soil domain at the bottom of the soil is considered, we find a gradual decrease in the age on the rising limb of nitrate efflux and a gradual increase on the falling limb. In addition, the age of the nitrate efflux ranges from 4 to 7 years. These are significantly higher as compared to the ages associated with a nonreactive tracer indicating that they provide an inaccurate estimate of residence time of a reactive constituent through the soil column.

  1. Transport of ARS-labeled hydroxyapatite nanoparticles in saturated granular media is influenced by surface charge variability even in the presence of humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dengjun [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing 210008 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Bradford, Scott A. [U.S. Salinity Laboratory, Agricultural Research Service, United States Department of Agriculture, 450 W. Big Springs Road, Riverside, CA 92507 (United States); Harvey, Ronald W. [U.S. Geological Survey, 3215 Marine Street, Boulder, CO 80303 (United States); Hao, Xiuzhen [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing 210008 (China); Zhou, Dongmei, E-mail: dmzhou@issas.ac.cn [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing 210008 (China)

    2012-08-30

    Highlights: Black-Right-Pointing-Pointer The transport and retention kinetics of ARS-labeled hydroxyapatite nanoparticles (ARS-nHAP) were investigated over a range of ionic strengths in the presence of humic acid. Black-Right-Pointing-Pointer A two-site kinetic attachment model predicted both the breakthrough curves and retention profiles of ARS-nHAP quite well. Black-Right-Pointing-Pointer The retention profiles of ARS-nHAP exhibited hyperexponential shapes for all the test conditions. Black-Right-Pointing-Pointer Surface charge heterogeneities on the collector surfaces and especially within the ARS-nHAP population contributed to hyperexponential retention profiles. - Abstract: Hydroxyapatite nanoparticle (nHAP) is increasingly being used to remediate soils and water polluted by metals and radionuclides. The transport and retention of Alizarin red S (ARS)-labeled nHAP were investigated in water-saturated granular media. Experiments were carried out over a range of ionic strength (I{sub c}, 0-50 mM NaCl) conditions in the presence of 10 mg L{sup -1} humic acid. The transport of ARS-nHAP was found to decrease with increasing suspension I{sub c} in part, because of enhanced aggregation and chemical heterogeneity. The retention profiles (RPs) of ARS-nHAP exhibited hyperexponential shapes (a decreasing rate of retention with increasing transport distance) for all test conditions, suggesting that some of the attachment was occurring under unfavorable conditions. Surface charge heterogeneities on the collector surfaces and especially within the ARS-nHAP population were contributing causes for the hyperexponential RPs. Consideration of the effect(s) of I{sub c} in the presence of HA is needed to improve the efficacy of nHAP for scavenging metals and actinides in real soils and groundwater environments.

  2. Albanian violets of the section Melanium, their morphological variability, genetic similarity and their adaptations to serpentine or chalk soils.

    Science.gov (United States)

    Słomka, Aneta; Godzik, Barbara; Szarek-Łukaszewska, Grażyna; Shuka, Lulëzim; Hoef-Emden, Kerstin; Bothe, Hermann

    2015-02-01

    Violets of the section Melanium from Albanian serpentine and chalk soils were examined for their taxonomic affiliations, their ability to accumulate heavy metals and their colonization by arbuscular mycorrhizal fungi (AMF). The sequence analysis of the ITS1-5.8S rDNA-ITS2 region showed that all the sampled six Albanian violets grouped between Viola lutea and Viola arvensis, but not with Viola tricolor. The fine resolution of the ITS sequences was not sufficient for a further delimitation of the Albanian violets within the V. lutea-V. arvensis clade. Therefore, the Albanian violets were classified by a set of morphological characters. Viola albanica, Viola dukadjinica and Viola raunsiensis from serpentine soils as well as Viola aetolica from a chalk meadow were unambiguously identified, whereas the samples of Viola macedonica showed high morphological variability. All the violets, in both roots and shoots contained less than or similar levels of heavy metals as their harboring soils, indicating that they were heavy metal excluders. All the violets were strongly colonized by AMF with the remarkable exception of V. albanica. This violet lived as a scree creeper in shallow serpentine soil where the concentration of heavy metals was high but those of P, K and N were scarce. Copyright © 2014 Elsevier GmbH. All rights reserved.

  3. Beyond clay: Towards an improved set of variables for predicting soil organic matter content

    Science.gov (United States)

    Rasmussen, Craig; Heckman, Katherine; Wieder, William R.; Keiluweit, Marco; Lawrence, Corey R.; Berhe, Asmeret Asefaw; Blankinship, Joseph C.; Crow, Susan E.; Druhan, Jennifer; Hicks Pries, Caitlin E.; Marin-Spiotta, Erika; Plante, Alain F.; Schadel, Christina; Schmiel, Joshua P.; Sierra, Carlos A.; Thompson, Aaron; Wagai, Rota

    2018-01-01

    Improved quantification of the factors controlling soil organic matter (SOM) stabilization at continental to global scales is needed to inform projections of the largest actively cycling terrestrial carbon pool on Earth, and its response to environmental change. Biogeochemical models rely almost exclusively on clay content to modify rates of SOM turnover and fluxes of climate-active CO2 to the atmosphere. Emerging conceptual understanding, however, suggests other soil physicochemical properties may predict SOM stabilization better than clay content. We addressed this discrepancy by synthesizing data from over 5,500 soil profiles spanning continental scale environmental gradients. Here, we demonstrate that other physicochemical parameters are much stronger predictors of SOM content, with clay content having relatively little explanatory power. We show that exchangeable calcium strongly predicted SOM content in water-limited, alkaline soils, whereas with increasing moisture availability and acidity, iron- and aluminum-oxyhydroxides emerged as better predictors, demonstrating that the relative importance of SOM stabilization mechanisms scales with climate and acidity. These results highlight the urgent need to modify biogeochemical models to better reflect the role of soil physicochemical properties in SOM cycling.

  4. Variability of soil moisture proxies and hot days across the climate regimes of Australia

    Science.gov (United States)

    Holmes, A.; Rüdiger, C.; Mueller, B.; Hirschi, M.; Tapper, N.

    2017-07-01

    The frequency of extreme events such as heat waves are expected to increase due to the effect of climate change, particularly in semiarid regions of Australia. Recent studies have indicated a link between soil moisture deficits and heat extremes, focusing on the coupling between the two. This study investigates the relationship between the number of hot days (Tx90) and four soil moisture proxies (Standardized Precipitation Index, Antecedent Precipitation Index, Mount's Soil Dryness Index, and Keetch-Byram Drought Index), and how the strength of this relationship changes across various climate regimes within Australia. A strong anticorrelation between Tx90 and each moisture index is found, particularly for tropical savannas and temperate regions. However, the magnitude of the increase in Tx90 with decreasing moisture is strongest in semiarid and arid regions. It is also shown that the Tx90-soil moisture relationship strengthens during the El Niño phases of El Niño-Southern Oscillation in regions which are more sensitive to changes in soil moisture.

  5. Field-scale tracking of active methane-oxidizing communities in a landfill-cover soil reveals spatial and seasonal variability

    NARCIS (Netherlands)

    Henneberger, R.; Chiri, E.; Bodelier, P.L.E.; Frenzel, P.; Luke, C.; Schroth, M.H.

    2015-01-01

    Aerobic methane-oxidizing bacteria (MOB) in soils mitigate methane (CH4) emissions. We assessed spatial and seasonal differences in active MOB communities in a landfill cover soil characterized by highly variable environmental conditions. Field-based measurements of CH4 oxidation activity and

  6. Assessment of soil nutrient depletion and its spatial variability on smallholders' mixed farming systems in Ethiopia using partial versus full nutrient balances

    NARCIS (Netherlands)

    Haileslassie, A.; Priess, J.; Veldkamp, E.; Teketay, D.; Lesschen, J.P.

    2005-01-01

    Soil fertility depletion in smallholder farms is one of the fundamental biophysical causes for declining per capita food production in Ethiopia. In the present study, we assess soil nutrient depletion and its spatial variability for Ethiopia and its regional states, using nutrient balances as a

  7. A global data set of soil hydraulic properties and sub-grid variability of soil water retention and hydraulic conductivity curves

    Science.gov (United States)

    Montzka, Carsten; Herbst, Michael; Weihermüller, Lutz; Verhoef, Anne; Vereecken, Harry

    2017-07-01

    Agroecosystem models, regional and global climate models, and numerical weather prediction models require adequate parameterization of soil hydraulic properties. These properties are fundamental for describing and predicting water and energy exchange processes at the transition zone between solid earth and atmosphere, and regulate evapotranspiration, infiltration and runoff generation. Hydraulic parameters describing the soil water retention (WRC) and hydraulic conductivity (HCC) curves are typically derived from soil texture via pedotransfer functions (PTFs). Resampling of those parameters for specific model grids is typically performed by different aggregation approaches such a spatial averaging and the use of dominant textural properties or soil classes. These aggregation approaches introduce uncertainty, bias and parameter inconsistencies throughout spatial scales due to nonlinear relationships between hydraulic parameters and soil texture. Therefore, we present a method to scale hydraulic parameters to individual model grids and provide a global data set that overcomes the mentioned problems. The approach is based on Miller-Miller scaling in the relaxed form by Warrick, that fits the parameters of the WRC through all sub-grid WRCs to provide an effective parameterization for the grid cell at model resolution; at the same time it preserves the information of sub-grid variability of the water retention curve by deriving local scaling parameters. Based on the Mualem-van Genuchten approach we also derive the unsaturated hydraulic conductivity from the water retention functions, thereby assuming that the local parameters are also valid for this function. In addition, via the Warrick scaling parameter λ, information on global sub-grid scaling variance is given that enables modellers to improve dynamical downscaling of (regional) climate models or to perturb hydraulic parameters for model ensemble output generation. The present analysis is based on the ROSETTA PTF

  8. A global data set of soil hydraulic properties and sub-grid variability of soil water retention and hydraulic conductivity curves

    Directory of Open Access Journals (Sweden)

    C. Montzka

    2017-07-01

    Full Text Available Agroecosystem models, regional and global climate models, and numerical weather prediction models require adequate parameterization of soil hydraulic properties. These properties are fundamental for describing and predicting water and energy exchange processes at the transition zone between solid earth and atmosphere, and regulate evapotranspiration, infiltration and runoff generation. Hydraulic parameters describing the soil water retention (WRC and hydraulic conductivity (HCC curves are typically derived from soil texture via pedotransfer functions (PTFs. Resampling of those parameters for specific model grids is typically performed by different aggregation approaches such a spatial averaging and the use of dominant textural properties or soil classes. These aggregation approaches introduce uncertainty, bias and parameter inconsistencies throughout spatial scales due to nonlinear relationships between hydraulic parameters and soil texture. Therefore, we present a method to scale hydraulic parameters to individual model grids and provide a global data set that overcomes the mentioned problems. The approach is based on Miller–Miller scaling in the relaxed form by Warrick, that fits the parameters of the WRC through all sub-grid WRCs to provide an effective parameterization for the grid cell at model resolution; at the same time it preserves the information of sub-grid variability of the water retention curve by deriving local scaling parameters. Based on the Mualem–van Genuchten approach we also derive the unsaturated hydraulic conductivity from the water retention functions, thereby assuming that the local parameters are also valid for this function. In addition, via the Warrick scaling parameter λ, information on global sub-grid scaling variance is given that enables modellers to improve dynamical downscaling of (regional climate models or to perturb hydraulic parameters for model ensemble output generation. The present analysis is based

  9. Spatial variability of soil and vegetation characteristics in an urban park in Tel-Aviv

    Science.gov (United States)

    Sarah, Pariente; Zhevelev, Helena M.; Oz, Atar

    2010-05-01

    Mosaic-like spatial patterns, consisting of divers soil microenvironments, characterize the landscapes of many urban parks. These microenvironments may differ in their pedological, hydrological and floral characteristics, and they play important roles in urban ecogeomorphic system functioning. In and around a park covering 50 ha in Tel Aviv, Israel, soil properties and herbaceous vegetation were measured in eight types of microenvironments. Six microenvironments were within the park: area under Ceratonia siliqua (Cs-U), area under Ficus sycomorus (Fi-U), a rest area under F. sycomorus (Re-U), an open area with bare soil (Oa-S), an open area with biological crusts (Oa-C), and an open area with herbaceous vegetation (Oa-V). Outside the park were two control microenvironments, located, respectively, on a flat area (Co-P) and an inclined open area (Co-S). The soil was sampled from two depths (0-2 and 5-10 cm), during the peak of the growing season (March). For each soil sample, moisture content, organic matter content, CaCO3 content, texture, pH, electrical conductivity, and soluble ions contents were determined in 1:1 water extraction. In addition, prior to the soil sampling, vegetation cover, number of species, and species diversity of herbaceous vegetation were measured. The barbecue fires and visitors in each of the microenvironments were counted. Whereas the soil organic matter and vegetation in Fi-U differed from those in the control(Co-P, Co-S), those in Oa-V were similar to those in the control. Fi-U was characterized by higher values of soil moisture, organic matter, penetration depth, and vegetation cover than Cs-U. Open microenvironments within the park (Oa-S, Oa-C, Oa-V) showed lower values of soil penetration than the control microenvironments. In Oa-V unique types of plants such as Capsella bursa-pastoris and Anagallis arvensis, which did not appear in the control microenvironments, were found. This was true also for Fi-U, in which species like Oxalis pes

  10. Transport of ARS-labeled hydroxyapatite nanoparticles in saturated granular media is influenced by surface charge variability even in the presence of humic acid

    Science.gov (United States)

    Wang, Dengjun; Bradford, Scott A.; Harvey, Ronald W.; Hao, Xiuzhen; Zhou, Dongmei

    2012-01-01

    Hydroxyapatite nanoparticle (nHAP) is increasingly being used to remediate soils and water polluted by metals and radionuclides. The transport and retention of Alizarin red S (ARS)-labeled nHAP were investigated in water-saturated granular media. Experiments were carried out over a range of ionic strength (Ic, 0–50 mM NaCl) conditions in the presence of 10 mg L−1 humic acid. The transport of ARS-nHAP was found to decrease with increasing suspension Ic in part, because of enhanced aggregation and chemical heterogeneity. The retention profiles (RPs) of ARS-nHAP exhibited hyperexponential shapes (a decreasing rate of retention with increasing transport distance) for all test conditions, suggesting that some of the attachment was occurring under unfavorable conditions. Surface charge heterogeneities on the collector surfaces and especially within the ARS-nHAP population were contributing causes for the hyperexponential RPs. Consideration of the effect(s) of Ic in the presence of HA is needed to improve the efficacy of nHAP for scavenging metals and actinides in real soils and groundwater environments.

  11. Variability of Soil Micronutrients Concentration along the Slopes of Mount Kilimanjaro, Tanzania

    Directory of Open Access Journals (Sweden)

    Mathayo Mpanda Mathew

    2016-01-01

    Full Text Available Soil micronutrients are important elements for plant growth despite being required in small quantities. Deficiency of micronutrients can result in severe crop failure while excess levels can lead to health hazards; therefore, investigating their status in agricultural land is crucial. Fifty plots were established along an altitudinal gradient from 680 to 1696 m a.s.l. on the slopes of Mount Kilimanjaro, Tanzania. Soils were sampled at the top- (0–20 cm and subsoils (21–50 cm in four locations within each plot. Fourier Transform Mid-Infrared (FT-MIR spectroscopy and wet chemistry were used for soil analysis. Results indicated that the mean concentrations of the micronutrients in the topsoil were Fe (130.4±6.9 mgkg−1, Mn (193.4±20.5 mgkg−1, Zn (2.8±0.2 mgkg−1, B (0.68±0.1 mgkg−1, and Cu (8.4±0.8 mgkg−1. Variations of the micronutrients were not statistically different by elevation (df = 41, p>0.05 and by soil depth (df = 49, p>0.05. Correlations among micronutrients were significant for Fe versus Mn (r=0.46, p<0.001, B versus Zn (r=0.40, p=0.003, B versus Cu (r=0.34, p=0.013, and Cu versus Zn (r=0.88, p<0.001. The correlated micronutrients implied that they were affected by similar factors. Soil pH correlated positively with B, Fe, and Mn and negatively with Cu and Zn, hence probably influencing their availability. Therefore, the need for sustaining micronutrient at sufficient levels is crucial. Management interventions may include moderating soil pH by reducing acidity through liming in the higher elevations and incorporation of organic matter in the lowlands.

  12. Variable pore connectivity model linking gas diffusivity and air-phase tortuosity to soil matric potential

    DEFF Research Database (Denmark)

    Chamindu, Deepagoda; Møldrup, Per; Schjønning, Per

    2012-01-01

    Soil-gas diffusivity (Dp/Do) and its dependency on soil matric potential (ψ) is important when taking regulative measures (based on accurate predictions) for climate gas emissions and also risk-mitigating measures (based on upper-limit predictions) of gaseous-phase contaminant emissions. Useful...... that accounts for water blockage. The X–pF relation can be linked to drained pore size to explain the lower probability of the larger but far fewer air-filled pores at lower pF effectively interconnecting and promoting gas diffusion. The model with X* = 2 and A = 0.5 proved promising for generalizing Dp...

  13. A Molecular Investigation of Soil Organic Carbon Composition, Variability, and Spatial Distribution Across an Alpine Catchment

    Science.gov (United States)

    Hsu, H. T.; Lawrence, C. R.; Winnick, M.; Druhan, J. L.; Williams, K. H.; Maher, K.; Rainaldi, G. R.; McCormick, M. E.

    2016-12-01

    The cycling of carbon through soils is one of the least understood aspects of the global carbon cycle and represents a key uncertainty in the prediction of land-surface response to global warming. Thus, there is an urgent need for advanced characterization of soil organic carbon (SOC) to develop and evaluate a new generation of soil carbon models. We hypothesize that shifts in SOC composition and spatial distribution as a function of soil depth can be used to constrain rates of transformation between the litter layer and the deeper subsoil (extending to a depth of approximately 1 m). To evaluate the composition and distribution of SOC, we collected soil samples from East River, a shale-dominated watershed near Crested Butte, CO, and characterized relative changes in SOC species as a function of depth using elemental analysis (EA), Fourier transform infrared spectroscopy (FT-IR) and bulk C X-ray absorption spectroscopy (XAS). Our results show that total organic carbon (TOC) decreases with depth, and high total inorganic carbon (TIC) content was found in deeper soils (after 75 cm), a characteristic of the bedrock (shale). The distribution of aliphatic C relative to the parent material generally decreases with depth and that polysaccharide can be a substantial component of SOC at various depths. On the other hand, the relative distribution of aromatic C, traditionally viewed as recalcitrant, only makes up a very small part of SOC regardless of depth. These observations confirm that molecular structure is not the only determinant of SOC turnover rate. To study other contributors to SOC decomposition, we studied changes in the spatial correlation of SOC and minerals using X-ray fluorescence spectroscopy (XRF) and scanning transmission X-ray microscopy (STXM). We found that aromatics mostly locate on the surface of small soil aggregates (1-10 μm). Polysaccharides and proteins, both viewed as labile traditionally, are more evenly distributed over the interior of the

  14. 471 Soil Characterization and Land Use of Arondizogu Inland Valley ...

    African Journals Online (AJOL)

    User

    2010-10-16

    Oct 16, 2010 ... result of demographic pressure on static land resources the traditional land use system (shifting cultivation) was abandoned and rotational bush fallow .... negative charges which is evidence by the presence of variable charge colloids such as sesqioxides. Soil Characterization and Land use of Arondizogu ...

  15. Spatial variability of cv Tempranillo phenology within the Ribera del Duero DO (Spain) related to soil type and plot characteristics

    Science.gov (United States)

    Ramos, Maria C.; Jones, Gregory V.; Yuste, Jesús

    2014-05-01

    Vineyards in the Ribera del Duero area (Spain) date back to the roman time, with significant fluctuations throughout the centuries, reaching consolidation and stable production in the 10th and 11th centuries. The present Ribera del Duero Designation of Origen (DO) started in 1980 and has increased from less than 6,000 ha planted to more than 21,000 ha planted by 2010 and becoming one the top regions for wine production in Spain with success in the global wine market. Vineyards of Ribera del Duero are found along 115 km of the Duero River. Within this distance, differences in elevation and topography produce differences in climate, which provide the means by which a zonification for vineyard management can be assessed. In this work, the differences in phenological growth characteristics for the Tempranillo variety were analyzed within the Ribera del Duero DO and related to soil and plot characteristics. Phenology dates, referenced to different Baggiolini classification stages, were evaluated in 20 control plots distributed throughout the Ribera del Duero DO during the period 2004-2012. These years presented different climatic characteristics, which were analyzed from daily temperature and precipitation series recorded from 1980 to 2012 at five stations located along the Duero River. Most vineyards were cultivated under rainfed conditions. In order to evaluate the spatial variability in phenology, climate and soils, the plots were classified using a hierarchical cluster multivariate analysis. Parameters such as the elevation, the distance to river and the soil type were taken into account in the classification. According to the WRB classification (2006) the main soil types in the area are Calcaric Cambisols, Eutric Cambisols, Calcic Luvisol, Calcaric fluvisols, Eutric fluvisols and in less proportion Lithic Leptosols and Calcaric Rogosols. Four different groups were observed, with differences in elevation, distance to the Duero River and the soil type. The

  16. County-Scale Spatial Variability of Macronutrient Availability Ratios in Paddy Soils

    Directory of Open Access Journals (Sweden)

    Mingkai Qu

    2014-01-01

    Full Text Available Macronutrients (N, P, and K are essential to plants but also can be harmful to the environment when their available concentrations in soil are excessive. Availability ratios (available concentration/total concentration of macronutrients may reflect their transforming potential between fixed and available forms in soil. Understanding their spatial distributions and impact factors can be, therefore, helpful to applying specific measures to modify the availability of macronutrients for agricultural and environmental management purposes. In this study, 636 topsoil samples (0–15 cm were collected from paddy fields in Shayang County, Central China, for measuring soil properties. Factors influencing macronutrient availability ratios were investigated, and total and available concentrations of macronutrients were mapped using geostatistical method. Spatial distribution maps of macronutrient availability ratios were further derived. Results show that (1 availability of macronutrients is controlled by multiple factors, and (2 macronutrient availability ratios are spatially varied and may not always have spatial patterns identical to those of their corresponding total and available concentrations. These results are more useful than traditional soil macronutrient average content data for guiding site-specific field management for agricultural production and environmental protection.

  17. Microscale heterogeneity explains experimental variability and non-linearity in soil organic matter mineralisation.

    Directory of Open Access Journals (Sweden)

    Ruth E Falconer

    Full Text Available Soil respiration represents the second largest CO2 flux from terrestrial ecosystems to the atmosphere, and a small rise could significantly contribute to further increase in atmospheric CO2. Unfortunately, the extent of this effect cannot be quantified reliably, and the outcomes of experiments designed to study soil respiration remain notoriously unpredictable. In this context, the mathematical simulations described in this article suggest that assumptions of linearity and presumed irrelevance of micro-scale heterogeneity, commonly made in quantitative models of microbial growth in subsurface environments and used in carbon stock models, do not appear warranted. Results indicate that microbial growth is non-linear and, at given average nutrient concentrations, strongly dependent on the microscale distribution of both nutrients and microbes. These observations have far-reaching consequences, in terms of both experiments and theory. They indicate that traditional, macroscopic soil measurements are inadequate to predict microbial responses, in particular to rising temperature conditions, and that an explicit account is required of microscale heterogeneity. Furthermore, models should evolve beyond traditional, but overly simplistic, assumptions of linearity of microbial responses to bulk nutrient concentrations. The development of a new generation of models along these lines, and in particular incorporating upscaled information about microscale processes, will undoubtedly be challenging, but appears to be key to understanding the extent to which soil carbon mineralization could further accelerate climate change.

  18. Spatial Variability of Heavy Metals in Soils and Sediments of “La Zacatecana” Lagoon, Mexico

    Directory of Open Access Journals (Sweden)

    Sergio A. Covarrubias

    2018-01-01

    Full Text Available Anthropogenic activities have greatly increased heavy metal pollution worldwide. Due to inadequate waste management, mining is one of the chief causes. One particularly affected area in Mexico is the “La Zacatecana” Lagoon, in the municipality of Guadalupe, Zacatecas. From colonial times until the mid-nineteenth century, about 20 million tons of mine tailings were deposited at this site. Here, we catalogue the heavy metal content and their distribution in soils and sediments of La Zacatecana. The mobility of lead in soils was also assayed by sequential extraction. Concentrations of the different metals analysed were as follows: Pb > Cr > As > Ni > Hg > Cd. Site VIII accumulated the highest amount of Pb (3070 mg·kg−1 sevenfold more than the limit established by the Mexican standards for agricultural soils (i.e., 400 mg·kg−1. On the other hand, the contents of Cd, Cr, and Ni were within the levels accepted by the above normativity, set at 37, 280, and 1600 mg·kg−1, respectively. Concentrations of Hg and Pb were highest in the north-northwest zone of the lagoon and decreased towards the southeast. Except for Site VIII where 30% of the Pb was in an interchangeable form or bound to carbonates, most Pb in La Zacatecana soils was present in an unavailable form, associated with Fe-Mn oxides.

  19. Variability and scaling of hydraulic properties for 200 Area soils, Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Khaleel, R.; Freeman, E.J.

    1995-10-01

    Over the years, data have been obtained on soil hydraulic properties at the Hanford Site. Much of these data have been obtained as part of recent site characterization activities for the Environmental Restoration Program. The existing data on vadose zone soil properties are, however, fragmented and documented in reports that have not been formally reviewed and released. This study helps to identify, compile, and interpret all available data for the principal soil types in the 200 Areas plateau. Information on particle-size distribution, moisture retention, and saturated hydraulic conductivity (K{sub s}) is available for 183 samples from 12 sites in the 200 Areas. Data on moisture retention and K{sub s} are corrected for gravel content. After the data are corrected and cataloged, hydraulic parameters are determined by fitting the van Genuchten soil-moisture retention model to the data. A nonlinear parameter estimation code, RETC, is used. The unsaturated hydraulic conductivity relationship can subsequently be predicted using the van Genuchten parameters, Mualem`s model, and laboratory-measured saturated hydraulic conductivity estimates. Alternatively, provided unsaturated conductivity measurements are available, the moisture retention curve-fitting parameters, Mualem`s model, and a single unsaturated conductivity measurement can be used to predict unsaturated conductivities for the desired range of field moisture regime.

  20. The Effect of Restoration Treatments on the Spatial Variability of Soil Processes under Longleaf Pine Trees

    Directory of Open Access Journals (Sweden)

    John K. Hiers

    2012-08-01

    Full Text Available The objectives of this study were to (1 characterize tree-based spatial patterning of soil properties and understory vegetation in frequently burned (“reference state” and fire-suppressed longleaf pine forests; and (2 determine how restoration treatments affected patterning. To attain these objectives, we used an experimental manipulation of management types implemented 15 years ago in Florida. We randomly located six mature longleaf pine trees in one reference and four restoration treatments (i.e., burn, control, herbicide, and mechanical, for a total of 36 trees. In addition to the original treatments and as part of a monitoring program, all plots were subjected to several prescribed fires during these 15 years. Under each tree, we sampled mineral soil and understory vegetation at 1 m, 2 m, 3 m and 4 m (vegetation only away from the tree. At these sites, soil carbon and nitrogen were higher near the trunk while graminoids, forbs and saw palmetto covers showed an opposite trend. Our results confirmed that longleaf pine trees affect the spatial patterning of soil and understory vegetation, and this patterning was mostly limited to the restoration sites. We suggest frequent burning as a probable cause for a lack of spatial structure in the “reference state”. We attribute the presence of spatial patterning in the restoration sites to accumulation of organic materials near the base of mature trees.

  1. Effects of variability of meteorological measures on soil temperature in permafrost regions

    OpenAIRE

    Beer, Christian; Porada, Philipp; Ekici, Altug; Brakebusch, Matthias

    2016-01-01

    To clarify effects of the variability of meteorological measures and their extreme events on topsoil and subsoil temperature in permafrost regions, an artificially manipulated climate dataset has been used for process-oriented model experiments. Climate variability mainly impacts snow depth, and the cover and thermal diffusivity of lichens and bryophytes. The latter effect is of opposite direction in summer and winter. These impacts of climate variability on insulating layers together substan...

  2. RELATION OF CEREALS YIELDS AND VARIABILITY TO SOIL-CLIMATE AND PRODUCTION CHARACTERISTICS OF DISTRICTS OF THE CZECH REPUBLIC

    Directory of Open Access Journals (Sweden)

    Jan HABERLE

    2007-07-01

    Full Text Available The relations between yields (Y or yield year-to-year variability (YV of winter wheat and spring barley in years 1993- 2001 in districts of the Czech Republic to environmental and production indicators were studied. We found mostly significant relationships between Y and soil conditions, average precipitation and temperature, fertilizer consumption, animal production and concentration of cereals. Fertilizers explained up to 70 % of Y differences among districts, but other factors only 50 % and less. The relations of YV and the indicators were mostly weaker than that of Y.

  3. PAHs contamination in urban soils from Lisbon: spatial variability and potential risks

    Science.gov (United States)

    Cachada, Anabela; Pereira, Ruth; Ferreira da Silva, Eduardo; Duarte, Armando

    2015-04-01

    Polycyclic Aromatic hydrocarbons (PAHs) can become major contaminants in urban and industrial areas, due to the existence of a plethora of diffuse and point sources. Particularly diffuse pollution, which is normally characterized by continuous and long-term emission of contaminants below risk levels, can be a major problem in urban areas. Since PAHs are persistent and tend to accumulate in soils, levels are often above the recommended guidelines indicating that ecological functions of soils may be affected. Moreover, due to the lipophilic nature, hydrophobicity and low chemical and biological degradation rates of PAHs, which leads to their bioconcentration and bioamplification, they may reach toxicological relevant concentrations in organisms. The importance and interest of studying this group of contaminants is magnified due to their carcinogenic, mutagenic and endocrine disrupting effects. In this study, a risk assessment framework has been followed in order to evaluate the potential hazards posed by the presence of PAHs in Lisbon urban soils. Hence, the first step consisted in screening the total concentrations of PAHs followed by the calculation of risks based on existing models. Considering these models several samples were identified as representing a potential risk when comparing with the guidelines for soil protection. Moreover, it was found that for 38% of samples more than 50% of species can be potentially affected by the mixture of PAHs. The use of geostatistical methods allowed to visualize the predicted distribution of PAHs in Lisbon area and identify the areas where possible risk to the environment are likely occurring However, it is known that total concentration may not allow a direct prediction of environmental risk, since in general only a fraction of total concentration is available for partitioning between soil and solution and thus to be uptake or transformed by organisms (bioacessible or bioavailable) or to be leached to groundwater. The

  4. Topography and spatial variability of soil physical properties Topografia e variabilidade espacial de propriedades físicas do solo

    Directory of Open Access Journals (Sweden)

    Marcos Bacis Ceddia

    2009-06-01

    Full Text Available Among the soil formation factors, relief is one of the most used in soil mapping, because of its strong correlation with the spatial variability of soil attributes over a landscape. In this study the relationship between topography and the spatial variability of some soil physical properties was evaluated. The study site, a pasture with 2.84 ha, is located near Seropédica, Rio de Janeiro State, Brazil, where a regular square grid with 20 m spacing was laid out and georreferenced. In each sampling point, altitude was measured and undisturbed soil samples were collected, at 0.0-0.1, 0.1-0.2, and 0.2-0.3 m depths. Organic carbon content, soil texture, bulk density, particle density, and soil water retention at 10 (Field Capacity, 80 (limit of tensiometer reading and 1500 kPa (Permanent Wilting Point were determined. Descriptive statistics was used to evaluate central tendency and dispersion parameters of the data. Semivariograms and cross semivariograms were calculated to evaluate the spatial variability of elevation and soil physical attributes, as well as, the relation between elevation and soil physical attributes. Except for silt fraction content (at the three depths, bulk density (at 0.2-0.3 m and particle density (at 0.0-0.1 m depth, all soil attributes showed a strong spatial dependence. Areas with higher elevation presented higher values of clay content, as well as soil water retention at 10, 80 and 1500 kPa. The correlation between altitude and soil physical attributes decreased as soil depth increased. The cross semivariograms demonstrated the viability in using altitude as an auxiliary variable to improve the interpolation of sand and clay contents at the depth of 0.0-0.3 m, and of water retention at 10, 80 and 1500 kPa at the depth of 0.0-0.2 m.O relevo é um dos fatores de formação do solo mais usados em mapeamento de solos devido sua forte correlação com a variabilidade espacial de atributos do solo na paisagem. O objetivo desse

  5. Evaluation of spatial variability of metal bioavailability in soils using geostatistics

    DEFF Research Database (Denmark)

    Owsianiak, Mikolaj; Hauschild, Michael Zwicky; Rosenbaum, Ralph K.

    2012-01-01

    is performed using ArcGIS Geostatistical Analyst. Results show that BFs of copper span a range of 6 orders of magnitude, and have signifficant spatial variability at local and continental scales. The model nugget variance is signifficantly higher than zero, suggesting the presence of spatial variability...

  6. Is CH4 consumption by soils controlled by physics or biology? Results from a study of plot-scale variability of greenhouse gas fluxes

    Science.gov (United States)

    Maier, Martin; Paulus, Sinikka; Nicolai, Clara; Nauer, Philipp

    2017-04-01

    Soil-atmosphere fluxes of trace gases vary on different spatial scales, between landscapes and ecosystems down to the plot scale within apparently homogenous sites. The production and consumption of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) underlie different spatial and temporal changes, und thus, their interrelation is difficult to unravel. Small-scale variability in soil properties is well-known from soil surveys, affecting theoretically water availability for plants, soil aeration, vegetation, the local photosynthesis rate, and, eventually, greenhouse gas fluxes. We investigated the small scale variability of greenhouse gas fluxes in a homogenous Scots Pine stand in a former riparian flood plain. Soil-atmosphere fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) were carried out at 60 points on a 250 m2 plot with strata of diverse soil substrates and understory vegetation. Gas flux measurements were combined with soil physical lab measurements, and a soil vegetation survey. The soil was a source of CO2 and a sink for CH4 and N2O. No correlations between the fluxes and only weak correlations between the fluxes and soil physical factors were observed. CH4 and CO2 fluxes were significantly different for the soil-vegetation strata. Separating the dataset into the different soil-vegetation strata showed that CH4 consumption increased significantly with soil gas diffusivity and soil respiration. Methane consumption in the silt stratum was higher at a given soil gas diffusivity than in the sand stratum, indicating a higher methanotrophic microbe population and thus better habitats in silt. CH4 consumption increased with soil respiration in all strata, so that we speculate that the rhizosphere and decomposing organic litter (as origin of most of the soil respiration) facilitate a preferred habitat of methanotrophic microbes. The patterns of N2O consumption were more complex, but consumption seemed to be limited at locations with

  7. Spatial variability of soil chemical properties and its effect on crop yields: a case study in maize (Zea mays L. on the Bogota Plateau

    Directory of Open Access Journals (Sweden)

    Sánchez T. Jaiver D.

    2011-08-01

    Full Text Available

    To evaluate the effect of soil chemical properties on the crop yield of corn, in the context of site-specific fertilization, it was characterized the spatio-temporal variability of these properties and crop yield in a lot at the Centro Agropecuario Marengo of the Universidad Nacional de Colombia (Mosquera, Colombia. Using a systematic sampling grid of 32 points (25 x 25 m, soil samples were taken before crop sowing and 60 days after sowing (das to determine soil pH, N (%; Ca, K, Mg, Na, Al, H (cmol+ kg-1, P, Cu, Fe, Mn, Zn and B (mg kg-1. At 162 das, harvest and yield components were evaluated by site. The data was processed using multivariate procedures, descriptive analysis and geostatistical analysis. Emergent properties were obtained from the original chemical variables using principal component analysis (PCA; these new variables were evaluated using geostatistical analysis to show spatial distribution and its correlation with crop yield. The PCA allowed the finding of three patterns of spatial variability in the soil corresponding to the variables related to soil fertility OC, Ca, Mg, K, CIC and B, the availability of nutrients by soil redox potential, and the variability associated with salinity explained by the Na content and soil electrical conductivity. The first group of variables largely explains the spatial variability of crop yield of corn.

  8. Experimental and modelling investigations of tracer transport in variably saturated agricultural soil of Thailand: Column study

    Directory of Open Access Journals (Sweden)

    Tulaya Masipan

    2016-03-01

    Full Text Available Tracer (Bromide movement through the unsaturated agricultural soil was investigated in soil columns. Two tracer column experiments, with a diameter of 7 cm and a depth of 25 cm, were vertically homogeneous packed with sandy loam and then carried out to investigate bromide (Br− transport under different water contents (at steady flow condition. One soil column (Column 1 represents the unsaturated agricultural soil in dry season (with water content ranging from 0.23 to 0.26 and the other (Column 2 represents the soil in wet season (water content from 0.24 to 0.35. Bromide samples were periodically collected by vacuum tubes inserted at 6.25 cm equally spaced intervals (e.g., 6.25, 12.5, 18.75 and 25 cm along the length of the column and the effluent collected at the end of the column. The observed breakthrough curves (BTCs of bromide in both columns represented a relative smooth and sigmodal curves at different distances (sampling ports. Dispersivity (α, cm for sandy loam at different locations was numerically estimated by curve fitting the experimental data with HYDRUS-1D. The α can be well described by the convection–dispersion equation and these values derived from Column 1 (ranging from 0.37 to 0.98 cm are more than those from Column 2 (0.25–0.59. Moreover, the α in both columns increases with the travel distance due to the scale-dependent effect. Furthermore, the α values were plotted on a log–log scale against travel distances and they yield empirical power law relationships with an excellent correlation (α = 0.102 (L0.697, R2 = 0.999 and α = 0.086 (L0.579, R2 = 0.963 for Column 1 and 2, respectively.

  9. Spatial variability of the physical and mineralogical properties of the soil from the areas with variation in landscape shapes

    Directory of Open Access Journals (Sweden)

    Zigomar Menezes de Souza

    2009-04-01

    Full Text Available The objective of this work it was to use the geostatistics methods to investigate the spatial relationships between the physical and mineralogical properties of an oxisol planted with the sugarcane in an area of slight variations in the landform. The soil was sampled at 10 m regular intervals in the crossing points of a 100 x 100 m grid. At each point, the soil was collected at 0.0-0.2 m, 0.2-0.4 m and 0.4-0.6 m depths for the analyzes of physical properties and at 0.6-0.8 m for the mineralogical analyses. Both the Kt/Kt+Gb ratio and Kt relative crystallization level were higher in the compartment I than in the compartment II. As a consequence, the soil penetration resistance and bulk density were higher in the compartment I, while the macroporosity and Ksat were lower. Therefore, it was concluded that both the identification and mapping of a landform were efficient for understanding the spatial variability of the soil properties. Moreover, variations in the landscape shape promoted the differentiated variability of the physical and mineralogical soil properties: the more variable the landscape, the more variable was the soil properties.Este trabalho teve como objetivo avaliar a influência das formas do relevo na variabilidade espacial de atributos físicos e suas relações com a mineralogia da argila de um Latossolo Vermelho eutroférrico, utilizando a técnica da geoestatística. Os solos foram amostrados nos pontos de cruzamento de uma malha, com intervalos regulares de 10 m, nas profundidades de 0,0-0,2 m, 0,2-0,4 m e 0,4-0,6 m para os atributos físicos e 0,6-0,8 m para os atributos mineralógicos. Os valores médios para a densidade do solo e resistência do solo à penetração são maiores no compartimento I onde a relação Ct/Ct+Gb é relativamente maior, indicando a presença de maior teor de caulinita. No compartimento II a condutividade hidráulica e a macroporsidade são maiores, influenciados provavelmente pelo predomínio da

  10. Ground-based investigation of soil moisture variability within remote sensing footprints during the Southern Great Plains 1997 (SGP97) Hydrology Experiment

    NARCIS (Netherlands)

    Famiglietti, J.S.; Devereaux, J.A.; Laymon, C.A.; Tsegaye, T.; Houser, P.R.; Jackson, T.J.; Graham, S.T.; Rodell, M.; Oevelen, van P.J.

    1999-01-01

    Surface soil moisture content is highly variable in both space and time. While remote sensing provides an effective methodology for mapping surface moisture content over large areas, it averages within-pixel variability thereby masking the underlying heterogeneity observed at the land surface. This

  11. Effects of Direct Fuel Injection Strategies on Cycle-by-Cycle Variability in a Gasoline Homogeneous Charge Compression Ignition Engine: Sample Entropy Analysis

    Directory of Open Access Journals (Sweden)

    Jacek Hunicz

    2015-01-01

    Full Text Available In this study we summarize and analyze experimental observations of cyclic variability in homogeneous charge compression ignition (HCCI combustion in a single-cylinder gasoline engine. The engine was configured with negative valve overlap (NVO to trap residual gases from prior cycles and thus enable auto-ignition in successive cycles. Correlations were developed between different fuel injection strategies and cycle average combustion and work output profiles. Hypothesized physical mechanisms based on these correlations were then compared with trends in cycle-by-cycle predictability as revealed by sample entropy. The results of these comparisons help to clarify how fuel injection strategy can interact with prior cycle effects to affect combustion stability and so contribute to design control methods for HCCI engines.

  12. Riparian zone hydrology and soil water total organic carbon (TOC: implications for spatial variability and upscaling of lateral riparian TOC exports

    Directory of Open Access Journals (Sweden)

    T. Grabs

    2012-10-01

    Full Text Available Groundwater flowing from hillslopes through riparian (near-stream soils often undergoes chemical transformations that can substantially influence stream water chemistry. We used landscape analysis to predict total organic carbon (TOC concentration profiles and groundwater levels measured in the riparian zone (RZ of a 67 km2 catchment in Sweden. TOC exported laterally from 13 riparian soil profiles was then estimated based on the riparian flow–concentration integration model (RIM. Much of the observed spatial variability of riparian TOC concentrations in this system could be predicted from groundwater levels and the topographic wetness index (TWI. Organic riparian peat soils in forested areas emerged as hotspots exporting large amounts of TOC. These TOC fluxes were subject to considerable temporal variations caused by a combination of variable flow conditions and changing soil water TOC concentrations. Mineral riparian gley soils, on the other hand, were related to rather small TOC export rates and were characterized by relatively time-invariant TOC concentration profiles. Organic and mineral soils in RZs constitute a heterogeneous landscape mosaic that potentially controls much of the spatial variability of stream water TOC. We developed an empirical regression model based on the TWI to move beyond the plot scale and to predict spatially variable riparian TOC concentration profiles for RZs underlain by glacial till.

  13. Small-scale variability of metals in soil and composite sampling.

    Science.gov (United States)

    Einax, Jürgen W; Kraft, Jörg

    2002-01-01

    Soil pollution data is also strongly scattering at small scale. Sampling of composite samples, therefore, is recommended for pollution assessment. Different statistical methods are available to provide information about the accuracy of the sampling process. Autocorrelation and variogram analysis can be applied to investigate spatial relationships. Analysis of variance is a useful method for homogeneity testing. The main source of the total measurement uncertainty is the uncertainty arising from sampling. The sample mass required for analysis can also be estimated using an analysis of variance. The number of increments to be taken for a composite sample can be estimated by means of simple statistical formulae. Analytical results of composite samples obtained from different fusion procedures of increments can be compared by means of multiple mean comparison. The applicability of statistical methods and their advantages are demonstrated for a case study investigating metals in soil at a very small spatial scale. The paper describes important statistical tools for the quantitative assessment of the sampling process. Detailed results clearly depend on the purpose of sampling, the spatial scale of the object under investigation and the specific case study, and have to be determined for each particular case.

  14. Land use and soil organic matter in South Africa 1: A review on spatial variability and the influence of rangeland stock production

    Directory of Open Access Journals (Sweden)

    Pearson N.S. Mnkeni

    2011-05-01

    Full Text Available Degradation of soil as a consequence of land use poses a threat to sustainable agriculture in South Africa, resulting in the need for a soil protection strategy and policy. Development of such a strategy and policy require cognisance of the extent and impact of soil degradation processes. One of the identified processes is the decline of soil organic matter, which also plays a central role in soil health or quality. The spatial variability of organic matter and the impact of grazing and burning under rangeland stock production are addressed in this first part of the review. Data from uncoordinated studies showed that South African soils have low organic matter levels. About 58% of soils contain less than 0.5% organic carbon and only 4% contain more than 2% organic carbon. Furthermore, there are large differences in organic matter content within and between soil forms, depending on climatic conditions, vegetative cover, topographical position and soil texture. A countrywide baseline study to quantify organic matter contents within and between soil forms is suggested for future reference. Degradation of rangeland because of overgrazing has resulted in significant losses of soil organic matter, mainly as a result of lower biomass production. The use of fire in rangeland management decreases soil organic matter because litter is destroyed by burning. Maintaining or increasing organic matter levels in degraded rangeland soils by preventing overgrazing and restricting burning could contribute to the restoration of degraded rangelands. This restoration is of the utmost importance because stock farming uses the majority of land in South Africa.

  15. Analysis of Large Scale Spatial Variability of Soil Moisture Using a Geostatistical Method

    Science.gov (United States)

    2010-01-25

    consists of a heating element and thermocouple emplaced in epoxy in a hypodermic needle , which is encased in a porous ceramic matrix. This sensor is...1/A), where A is the decorrelation length. Kriging is an interpolation technique based on the theory of regionalized variables developed by

  16. Variability of water quality across headwater catchments with distinct soils and hydrologic systems in central Missouri

    Science.gov (United States)

    Surface water and groundwater contamination by herbicides and fertilizers continues to be a major water quality problem in central Missouri. The purpose of this study was to examine spatial variability of water quality among three different headwater catchments – Goodwater Creek Experimental Watersh...

  17. Variability of physicochemical and mineralogical characteristics of biological soil crusts at local scale in the Sahelian zone of western Niger

    Science.gov (United States)

    Cancès, B.; Gommeaux, G.; Marin, B.; Ponthieu, M.; Ralahimanana, C.; Ayachi, S.; Malam Issa, O.

    2012-04-01

    Biological soil crusts (BSC) are organo-mineral complexes resulting from the colonisation of soil surface by living microorganisms, mainly cyanobacteria. Their form, structure and composition vary depending on characteristics related to soils, biological composition and external factors (climate conditions and land uses). This study focussed on the influence of soil characteristics and human activities on BSC properties. BSC samples from Banizoumbou (Niger) taken on protected (ungrazed) and opened (grazed) fallow lands were analysed. BSC characteristics were investigated by using chemical and mineralogical techniques, microscopic and image analysis approach as well as measurements of chlorophyll a content. Hydrophobicity measurements were also performed by the water drop penetration time method. On the basis of their colour, two types of crusts have been identified : black BSC, which occur in protected and unprotected fallow, and red BSC, which only occur in depression zones of the protected fallow. The black crusts are dominated by quartz grains trapped in the network of the filaments of Cyanobacteria. A sandy texture and a reverse grading of mineral particles are typical of physical soil crusts called sieving crusts. The dark surface coloration of the BSC is related to the high density of filamentous Cyanobacteria. Black crusts samples from protected fallow exhibit high biomass related to high cover, whereas samples from grazed fallow lands showed low biomass related to low surface cover. In both cases, hydrophobicity measurements revealed that these BSC are wettable to slightlty water repellent. However, higher values of hydrophobicity were observed on ungrazed samples compared to their grazed counterpart. This variability is likely due to the difference of cover between the two types of samples. This type of BSC corresponds to a later successional stage than the red-coloured BSC. The red BSC has a loamy-sandy texture and a normal grading typical of physical

  18. Spatial variability in soil organic carbon in a tropical montane landscape: associations between soil organic carbon and land use, soil properties, vegetation, and topography vary across plot to landscape scales

    Science.gov (United States)

    de Blécourt, Marleen; Corre, Marife D.; Paudel, Ekananda; Harrison, Rhett D.; Brumme, Rainer; Veldkamp, Edzo

    2017-08-01

    Presently, the lack of data on soil organic carbon (SOC) stocks in relation to land-use types and biophysical characteristics prevents reliable estimates of ecosystem carbon stocks in montane landscapes of mainland SE Asia. Our study, conducted in a 10 000 ha landscape in Xishuangbanna, SW China, aimed at assessing the spatial variability in SOC concentrations and stocks, as well as the relationships of SOC with land-use types, soil properties, vegetation characteristics and topographical attributes at three spatial scales: (1) land-use types within a landscape (10 000 ha), (2) sampling plots (1 ha) nested within land-use types (plot distances ranging between 0.5 and 12 km), and (3) subplots (10 m radius) nested within sampling plots. We sampled 27 one-hectare plots - 10 plots in mature forests, 11 plots in regenerating or highly disturbed forests, and 6 plots in open land including tea plantations and grasslands. We used a sampling design with a hierarchical structure. The landscape was first classified according to land-use types. Within each land-use type, sampling plots were randomly selected, and within each plot we sampled within nine subplots. SOC concentrations and stocks did not differ significantly across the four land-use types. However, within the open-land category, SOC concentrations and stocks in grasslands were higher than in tea plantations (P soil properties, vegetation characteristics, and topographical attributes varied across spatial scales. Variability in SOC within plots was determined by litter layer carbon stocks (P tree basal area (P effects on SOC need an appropriate sampling design reflecting the controlling factors of SOC so that land-use effects will not be masked by the variability between and within sampling plots.

  19. Spatio-temporal variability of soil moisture and its effect on vegetation in a desertified aeolian riparian ecotone on the Tibetan Plateau, China

    Science.gov (United States)

    Li, Haidong; Shen, Weishou; Zou, Changxin; Jiang, Jiang; Fu, Lina; She, Guanghui

    2013-02-01

    SummarySoil moisture content is one of the limiting factors for natural vegetation succession in alpine river valleys on the Tibetan Plateau. However, its spatio-temporal variability and effect on artificial vegetation restoration has rarely been reported. In this paper, we conducted a case study to examine the spatio-temporal variability and vertical characteristics of soil moisture by setting up a 100 × 120 m experimental plot on aeolian sandy land in a riparian ecotone and analyzing the result data using a geo-statistical approach. The soil moisture contents at different depths all showed strong temporal variability, with the mean soil moisture ranging from 4% to 6% in spring, from 6% to 14% in summer and from 9% to 12% in autumn. The Gaussian semi-variogram model was the best fitted theoretical model for the spatial structure of soil moisture contents in different seasons, and soil moisture at the field scale showed strong spatial dependence. The spatial patterns of soil moisture all demonstrated strong similarity between depths with the strongest between 0-20 cm and 20-40 cm depths in autumn. The soil moisture content over the upper 60 cm was the key factor that restricted the seed germination and seedling growth, and it affected vegetation coverage and density. The precipitation, variations of river water level, elevation as well as landform types were the main factors determining the variations of soil moisture content in different seasons. The results have important implications for the ongoing vegetation restoration in the study area.

  20. FUSION OF ACTIVE AND PASSIVE MICROWAVE OBSERVATIONS TO CREATE AN ESSENTIAL CLIMATE VARIABLE DATA RECORD ON SOIL MOISTURE

    Directory of Open Access Journals (Sweden)

    W. Wagner

    2012-07-01

    Full Text Available Soil moisture was recently included in the list of Essential Climate Variables (ECVs that are deemed essential for IPCC (Intergovernmental Panel on Climate Change and UNFCCC (United Nations Framework Convention on Climate Change needs and considered feasible for global observation. ECVs data records should be as long, complete and consistent as possible, and in the case of soil moisture this means that the data record shall be based on multiple data sources, including but not limited to active (scatterometer and passive (radiometer microwave observations acquired preferably in the low-frequency microwave range. Among the list of sensors that can be used for this task are the C-band scatterometers on board of the ERS and METOP satellites and the multi-frequency radiometers SMMR, SSM/I, TMI, AMSR-E, and Windsat. Together, these sensors already cover a time period of more than 30 years and the question is how can observations acquired by these sensors be merged to create one consistent data record? This paper discusses on a high-level possible approaches for fusing the individual satellite data. It is argued that the best possible approach for the fusion of the different satellite data sets is to merge Level 2 soil moisture data derived from the individual satellite data records. This approach has already been demonstrated within the WACMOS project (http://wacmos.itc.nl/ funded by European Space Agency (ESA and will be further improved within the Climate Change Initiative (CCI programme of ESA (http://www.esa-cci.org/.

  1. Temporal variability in trace metal solubility in a paddy soil not reflected in uptake by rice (Oryza sativa L.).

    Science.gov (United States)

    Pan, Yunyu; Koopmans, Gerwin F; Bonten, Luc T C; Song, Jing; Luo, Yongming; Temminghoff, Erwin J M; Comans, Rob N J

    2016-12-01

    Alternating flooding and drainage conditions have a strong influence on redox chemistry and the solubility of trace metals in paddy soils. However, current knowledge of how the effects of water management on trace metal solubility are linked to trace metal uptake by rice plants over time is still limited. Here, a field-contaminated paddy soil was subjected to two flooding and drainage cycles in a pot experiment with two rice plant cultivars, exhibiting either high or low Cd accumulation characteristics. Flooding led to a strong vertical gradient in the redox potential (Eh). The pH and Mn, Fe, and dissolved organic carbon concentrations increased with decreasing Eh and vice versa. During flooding, trace metal solubility decreased markedly, probably due to sulfide mineral precipitation. Despite its low solubility, the Cd content in rice grains exceeded the food quality standards for both cultivars. Trace metal contents in different rice plant tissues (roots, stem, and leaves) increased at a constant rate during the first flooding and drainage cycle but decreased after reaching a maximum during the second cycle. As such, the high temporal variability in trace metal solubility was not reflected in trace metal uptake by rice plants over time. This might be due to the presence of aerobic conditions and a consequent higher trace metal solubility near the root surface, even during flooding. Trace metal solubility in the rhizosphere should be considered when linking water management to trace metal uptake by rice over time.

  2. Wettability of poultry litter biochars at variable pyrolysis temperatures and their impact on soil wettability and water retention relationships

    Science.gov (United States)

    Yi, S. C.; Witt, B.; Guo, M.; Chiu, P.; Imhoff, P. T.

    2012-12-01

    To reduce the impact of poultry farming on greenhouse gas emissions, poultry farming waste - poultry litter - can be converted to biofuel and biochar through slow-pyrolysis, with the biochar added to agricultural soil for nutrient enrichment and carbon sequestration. While biochars from source materials other than poultry litter have been shown to sequester carbon and increase soil fertility, there is considerable variability in biochar behavior - even with biochars created from the same source material. This situation is exacerbated by our limited understanding of how biochars alter physical, chemical, and biological processes in agricultural soils. The focus of this work is to develop a mechanistic understanding of how poultry litter (PL) biochars affect the hydrology, microbial communities, N2O emissions, and nitrogen cycling in agricultural soils. The initial focus is on the impact of PL biochar on soil hydrology. PL from Perdue AgriRecycle, LLC (Seaford, Delaware) was used to produce biochars at pyrolysis temperatures from 300°C to 600°C. To explore the impact of these biochars on soil wettability, the PL biochars were mixed with a 30/40 Accusand in mass fractions from 0% to 100%. The water contact angle was then measured using a goniometer on these sand/biochar mixtures using the sessile drop method and a single layer of sample particles. The PL biochars produced at temperatures between 300°C to 400°C were hydrophobic, while those pyrolized at > 400°C were hydrophilic. Water contact angles for samples with 100% biochar varied systematically with pyrolysis temperature, decreasing from 101.12° to 20.57° as the pyrolysis temperature increased from 300 to 600°C. Even for small amounts of hydrophobic biochar added to the hydrophilic sand, the contact angle of the mixture was altered: for sand/biochar mixtures containing only 2% hydrophobic PL biochar by weight, the contact angle of the mixture increased from ~ 8° (0% biochar) to 20° (2% biochar). For

  3. The variability of runoff and soil erosion in the Brazilian Cerrado biome due to the potential land use and climate changes

    Science.gov (United States)

    Alexandre Ayach Anache, Jamil; Wendland, Edson; Malacarne Pinheiro Rosalem, Lívia; Srivastava, Anurag; Flanagan, Dennis

    2017-04-01

    Changes in land use and climate can influence runoff and soil loss, threatening soil and water conservation in the Cerrado biome in Brazil. Due to the lack of long term observed data for runoff and soil erosion in Brazil, the adoption of a process-based model was necessary, representing the variability of both variables in a continuous simulation approach. Thus, we aimed to calibrate WEPP (Water Erosion Prediction Project) model for different land uses (undisturbed Cerrado, fallow, pasture, and sugarcane) under subtropical conditions inside the Cerrado biome; predict runoff and soil erosion for these different land uses; and simulate runoff and soil erosion considering climate change scenarios. We performed the model calibration using a 4-year dataset of observed runoff and soil loss in four different land uses (undisturbed Cerrado, fallow, pasture, and sugarcane). The WEPP model components (climate, topography, soil, and management) were calibrated according to field data. However, soil and management were optimized according to each land use using a parameter estimation tool. The observations were conducted between 2012 and 2015 in experimental plots (5 m width, 20 m length, 9% slope gradient, 3 replicates per treatment). The simulations were done using the calibrated WEPP model components, but changing the 4-year observed climate file by a 100-year dataset created with CLIGEN (weather generator) based on regional climate statistics. Afterwards, using MarkSim DSSAT Weather File Generator, runoff and soil loss were simulated using future climate scenarios for 2030, 2060, and 2090. To analyze the data, we used non-parametric statistics as data do not follow normal distribution. The results show that WEPP model had an acceptable performance for the considered conditions. In addition, both land use and climate can influence on runoff and soil loss rates. Potential climate changes which consider the increase of rainfall intensities and depths in the studied region may

  4. Estimation method of state-of-charge for lithium-ion battery used in hybrid electric vehicles based on variable structure extended kalman filter

    Science.gov (United States)

    Sun, Yong; Ma, Zilin; Tang, Gongyou; Chen, Zheng; Zhang, Nong

    2016-07-01

    Since the main power source of hybrid electric vehicle(HEV) is supplied by the power battery, the predicted performance of power battery, especially the state-of-charge(SOC) estimation has attracted great attention in the area of HEV. However, the value of SOC estimation could not be greatly precise so that the running performance of HEV is greatly affected. A variable structure extended kalman filter(VSEKF)-based estimation method, which could be used to analyze the SOC of lithium-ion battery in the fixed driving condition, is presented. First, the general lower-order battery equivalent circuit model(GLM), which includes column accumulation model, open circuit voltage model and the SOC output model, is established, and the off-line and online model parameters are calculated with hybrid pulse power characteristics(HPPC) test data. Next, a VSEKF estimation method of SOC, which integrates the ampere-hour(Ah) integration method and the extended Kalman filter(EKF) method, is executed with different adaptive weighting coefficients, which are determined according to the different values of open-circuit voltage obtained in the corresponding charging or discharging processes. According to the experimental analysis, the faster convergence speed and more accurate simulating results could be obtained using the VSEKF method in the running performance of HEV. The error rate of SOC estimation with the VSEKF method is focused in the range of 5% to 10% comparing with the range of 20% to 30% using the EKF method and the Ah integration method. In Summary, the accuracy of the SOC estimation in the lithium-ion battery cell and the pack of lithium-ion battery system, which is obtained utilizing the VSEKF method has been significantly improved comparing with the Ah integration method and the EKF method. The VSEKF method utilizing in the SOC estimation in the lithium-ion pack of HEV can be widely used in practical driving conditions.

  5. Spatial variability of soil pH and phosphorus in relation to soil run-off following slah-and-burn land clearing in Sumatra, Indonesia

    NARCIS (Netherlands)

    Rodenburg, J.; Stein, A.; Noordwijk, van M.; Ketterings, Q.M.

    2003-01-01

    Slash-and-burn land clearing on sloping land may lead to increased soil run-off following disappearance of the protective vegetative cover. In turn, soil run-off and redeposition affects soil fertility and spatial patterns of fertility parameters in a field. This study seeks to clarify the role of

  6. Control of fast non linear systems - application to a turbo charged SI engine with variable valve timing; controle des systemes rapides non lineaires - application au moteur a allumage commande turbocompresse a distribution variable

    Energy Technology Data Exchange (ETDEWEB)

    Colin, G.

    2006-10-15

    Spark ignition engine control has become a major issue for the compliance with emissions legislation while ensuring driving comfort. Engine down-sizing is one of the promising ways to reduce fuel consumption and resulting CO{sub 2} emissions. Combining several existing technologies such as supercharging and variable valve actuation, down-sizing is a typical example of the problems encountered in Spark Ignited (SI) engine control: nonlinear systems with saturation of actuators; numerous major physical phenomena not measurable; limited computing time; control objectives (consumption, pollution, performance) often competing. A methodology of modelling and model-based control (internal model and predictive control) for these systems is also proposed and applied to the air path of the down-sized engine. Models, physicals and generics, are built to estimate in-cylinder air mass, residual burned gases mass and air scavenged mass from the intake to the exhaust. The complete and generic engine torque control architecture for the turbo-charged SI engine with variable cam-shaft timing was tested in simulation and experimentally (on engine and vehicle). These tests show that new possibilities are offered in order to decrease pollutant emissions and optimize engine efficiency. (author)

  7. Intra-cultivar variability of the soil-to-grain transfer of fallout {sup 137}Cs and {sup 90}Sr for winter wheat

    Energy Technology Data Exchange (ETDEWEB)

    Schimmack, W. [GSF-National Research Center for Environment and Health, Institute of Radiation Protection, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany)]. E-mail: schimmack@gsf.de; Gerstmann, U. [GSF-National Research Center for Environment and Health, Institute of Radiation Protection, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany); Schultz, W. [GSF-National Research Center for Environment and Health, Institute of Radiation Protection, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany); Sommer, M. [Leibniz-Centre for Agricultural Landscape Research (ZALF) e.V., Institute of Soil Landscape Research, Eberswalder Strasse 84, D-15374 Muencheberg (Germany); University of Potsdam, Institute for Geoecology, P.O. Box 601 553, D-14415 Potsdam (Germany); Tschoepp, V. [GSF-National Research Center for Environment and Health, Institute of Radiation Protection, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany); Zimmermann, G. [Bavarian State Research Center for Agriculture, Voettinger Strasse 38, D-85354 Freising (Germany)

    2007-04-15

    Differences between the root uptake of fallout radionuclides by different cultivars ('inter-cultivar' variability) growing on the same field may be influenced not only by genetic differences of the cultivars, but also by the spatial variability of the soil-to-grain transfer within the cultivation area of each cultivar. This 'intra-cultivar' variability was investigated in 2001 and 2002 for {sup 137}Cs and {sup 90}Sr using three winter wheat cultivars with four replicates for each cultivar at three different sites in Bavaria, Germany. The intra-cultivar variability proved to be in the same range as the inter-cultivar variability which was determined earlier at the same sites for both radionuclides. An ANOVA of the {sup 137}Cs data set revealed that the variability of the {sup 137}Cs soil-to-grain transfer was caused by the soil and climate (year) at the field sites and the interaction of cultivar and field. A significant contribution of the factor 'cultivar' alone to the variability could not be detected. This may be due to the complex environmental conditions to which plants are exposed in field experiments. To find wheat cultivars with minimal uptake of fallout radionuclides it may be better to examine the molecular mechanisms of their root uptake in order to identify targets for breeding 'safer' plants.

  8. he Role of Aspect on Spatial Variability of Soil Properties and Quantitative, Qualitative, and Vegetative Properties of Peach in Saman Region, Shahrekord

    Directory of Open Access Journals (Sweden)

    nargess keyvani

    2017-06-01

    Full Text Available Introduction: Soils form from the interplay of five main factors namely parent material, time, climate, relief (topography and organisms. Topography is one of the local factors that has direct and indirect effects on soil formation, physical and chemical properties of soils. To understand the mutual relationship between topographic properties, soil properties and plant community (phytocoenosis, it is necessary to decide on the appropriate method for properly managing the soil resources. In addition to the soil properties, topography may affect the soil production indices as well. Soil production index and consequently its productivity will in turn affect the growth and fruiting. Insight about the pattern the spatial variability of soil properties can be used to manage the lands properly. This study was performed to investigate the spatial variability of soil properties regarding aspect and also the relationship of these changes with the quality and quantity of peach production in Saman region in Chaharmahal-Va-Bakhtiari province, Iran. Materials and Methods: The study area contained 1.5 hectare of 200-hectare peach gerdens belong to BaghGostaran Company located in Saman, Chaharmahal-Va-Bakhtiari Province. The soil moisture and temperature regimes are xeric and mesic, respectively. 136 soil samples were collected from 0-30 and 30-60 cm depths. Two peach trees around the soil samples were also selected. Then, soil physical and chemical properties including soil texture, percentage of calcium carbonate equivalent, organic carbon, plant available potassium, phosphorous, iron and zinc, pH and electrical conductivity were determined and fruit properties including branch length and diameter in the current year, number of fruits, total yield, average of fruit weight, TSS, tissue strength, pH, acid and extract percentage were measured. Finally, the dataset were analyzed using Statistica 6.0 software. Analysis of spatial data was calculated via variogram

  9. Sources of variability in fatty acid (FA) biomarkers in the application of compound-specific stable isotopes (CSSIs) to soil and sediment fingerprinting and tracing: A review

    Energy Technology Data Exchange (ETDEWEB)

    Reiffarth, D.G., E-mail: Dominic.Reiffarth@unbc.ca [Natural Resources and Environmental Studies Program, University of Northern British Columbia, 3333 University Way, Prince George, BC V2N 4Z9 (Canada); Petticrew, E.L., E-mail: Ellen.Petticrew@unbc.ca [Geography Program and Quesnel River Research Centre, University of Northern British Columbia, 3333 University Way, Prince George, BC V2N 4Z9 (Canada); Owens, P.N., E-mail: Philip.Owens@unbc.ca [Environmental Science Program and Quesnel River Research Centre, University of Northern British Columbia, 3333 University Way, Prince George, BC, V2N 4Z9 (Canada); Lobb, D.A., E-mail: David.Lobb@umanitoba.ca [Watershed Systems Research Program, University of Manitoba, 13 Freedman Crescent, Winnipeg, MB R3T 2N2 (Canada)

    2016-09-15

    Determining soil redistribution and sediment budgets in watersheds is often challenging. One of the methods for making such determinations employs soil and sediment fingerprinting techniques, using sediment properties such as geochemistry, fallout radionuclides, and mineral magnetism. These methods greatly improve the estimation of erosion and deposition within a watershed, but are limited when determining land use-based soil and sediment movement. Recently, compound-specific stable isotopes (CSSIs), which employ fatty acids naturally occurring in the vegetative cover of soils, offer the possibility of refining fingerprinting techniques based on land use, complementing other methods that are currently in use. The CSSI method has been met with some success; however, challenges still remain with respect to scale and resolution due to a potentially large degree of biological, environmental and analytical uncertainty. By better understanding the source of tracers used in CSSI work and the inherent biochemical variability in those tracers, improvement in sample design and tracer selection is possible. Furthermore, an understanding of environmental and analytical factors affecting the CSSI signal will lead to refinement of the approach and the ability to generate more robust data. This review focuses on sources of biological, environmental and analytical variability in applying CSSI to soil and sediment fingerprinting, and presents recommendations based on past work and current research in this area for improving the CSSI technique. A recommendation, based on current information available in the literature, is to use very-long chain saturated fatty acids and to avoid the use of the ubiquitous saturated fatty acids, C{sub 16} and C{sub 18}. - Highlights: • Compound-specific stable isotopes (CSSIs) of carbon may be used as soil tracers. • The variables affecting CSSI data are: biological, environmental and analytical. • Understanding sources of variability will lead

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

    Science.gov (United States)

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

    2017-01-01

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

  11. High Resolution Mapping of Soil Properties Using Remote Sensing Variables in South-Western Burkina Faso: A Comparison of Machine Learning and Multiple Linear Regression Models.

    Science.gov (United States)

    Forkuor, Gerald; Hounkpatin, Ozias K L; Welp, Gerhard; Thiel, Michael

    2017-01-01

    Accurate and detailed spatial soil information is essential for environmental modelling, risk assessment and decision making. The use of Remote Sensing data as secondary sources of information in digital soil mapping has been found to be cost effective and less time consuming compared to traditional soil mapping approaches. But the potentials of Remote Sensing data in improving knowledge of local scale soil information in West Africa have not been fully explored. This study investigated the use of high spatial resolution satellite data (RapidEye and Landsat), terrain/climatic data and laboratory analysed soil samples to map the spatial distribution of six soil properties-sand, silt, clay, cation exchange capacity (CEC), soil organic carbon (SOC) and nitrogen-in a 580 km2 agricultural watershed in south-western Burkina Faso. Four statistical prediction models-multiple linear regression (MLR), random forest regression (RFR), support vector machine (SVM), stochastic gradient boosting (SGB)-were tested and compared. Internal validation was conducted by cross validation while the predictions were validated against an independent set of soil samples considering the modelling area and an extrapolation area. Model performance statistics revealed that the machine learning techniques performed marginally better than the MLR, with the RFR providing in most cases the highest accuracy. The inability of MLR to handle non-linear relationships between dependent and independent variables was found to be a limitation in accurately predicting soil properties at unsampled locations. Satellite data acquired during ploughing or early crop development stages (e.g. May, June) were found to be the most important spectral predictors while elevation, temperature and precipitation came up as prominent terrain/climatic variables in predicting soil properties. The results further showed that shortwave infrared and near infrared channels of Landsat8 as well as soil specific indices of redness

  12. Modelling Pesticide Leaching At Column, Field and Catchment Scales Ii. Influence of Soil Variability On Small Scale Transfer Properties

    Science.gov (United States)

    Roulier, S.; Jarvis, N.

    The aim of this study was to investigate the differences in small scale transfer prop- erties in relation to variability of soil characteristics in a small undulating agricultural catchment (Vemmenhög, 9 km2), where texture and organic C content are strongly related to landscape position (see Gärdenäs et al., this session). Undisturbed soil col- umn samples (20 cm diameter, 20 cm height) were taken at two locations (4 columns at each location): on a hilltop (high clay content), and in a hollow (high C content). Transient leaching experiments for a tracer and a herbicide (MCPA) were carried out in two steps. After a first application of solute and pesticide the columns were ex- posed to natural rainfall. After one pore volume of drainage had flowed through the columns, they were transferred indoors. A second dose of tracer and pesticide was applied, and the columns were irrigated with half a pore volume of natural rainwa- ter. The breakthrough curves obtained for the hilltop columns showed strong evidence of macroporous flow. The flux concentrations and the resident concentration at the end of the experiment measured for the hollow columns suggested that the loss of pesticide from those columns is little. The MACRO model and the inverse modelling package SUFI were used to estimate the small scale parameters for water transfer, so- lute transport, and pesticide. Good agreement was obtained between model and data. Macroporous flow and diffusive transport through hilltop columns was highlighted by the high calibrated values of the effective diffusion pathlength and the dispersivity. As a consequence of the significant organic C content in the hollows, the value of the degradation rate coefficient for hollow columns was important. In both hilltop and hollow columns, the variation of the degradation rate coefficient between the first and the second application of MCPA showed the ability of the micro-organisms to adapt to the pesticide.

  13. Two-region, combined Archie’s Law and Reference-Point model for air permeability and gas diffusivity in variably-saturated soil

    DEFF Research Database (Denmark)

    Hamamoto, S; Møldrup, Per; Kawamoto, K

    2011-01-01

    for structured soils, with the natural field moisture condition (set at −100 cm H2O matric potential [pF 2]) as the reference (spliced) point between the large-pore (drained pore diameter ≥30 μm at pF ≤ 2) and the small-pore (subsequently drained pores 2) regions, and (ii) including a percolation...... threshold, set as 10% of the total porosity for structureless porous media or 10% of the porosity in the large-pore region for structured soils. The resulting extended Archie's law with reference point (EXAR) models for ka and Dp were fitted to the measured data. For both structureless and structured porous......The air permeability (ka) and soil gas diffusion coefficients (Dp) are controlling factors for gas transport and fate in variably saturated soils. We developed a unified model for ka and Dp based on the classical Archie's law, extended by: (i) allowing for two-region gas transport behavior...

  14. Spatial variability of soil N2O and CO2 fluxes in different topographic positions in a tropical montane forest in Kenya

    NARCIS (Netherlands)

    Arias-navarro, C.; Díaz-pinés, E.; Klatt, S.; Brandt, P.; Rufino, M.C.; Butterbach-bahl, K.; Verchot, L.V.

    2017-01-01

    Quantifying and understanding the small-scale variability of nitrous oxide (N2O) and carbon dioxide (CO2) emission are essential for reporting accurate ecosystem greenhouse gas budgets. The objective of this study was to evaluate the spatial pattern of soil CO2 and N2O emissions and their relation

  15. Concentrations of lead, cadmium and barium in urban garden-grown vegetables: the impact of soil variables

    Science.gov (United States)

    McBride, Murray B.; Shayler, Hannah A.; Spliethoff, Henry M.; Mitchell, Rebecca G.; Marquez-Bravo, Lydia G.; Ferenz, Gretchen S.; Russell-Anelli, Jonathan M.; Casey, Linda; Bachman, Sharon

    2014-01-01

    Paired vegetable/soil samples from New York City and Buffalo, NY, gardens were analyzed for lead (Pb), cadmium (Cd) and barium (Ba). Vegetable aluminum (Al) was measured to assess soil adherence. Soil and vegetable metal concentrations did not correlate; vegetable concentrations varied by crop type. Pb was below health-based guidance values (EU standards) in virtually all fruits. 47% of root crops and 9% of leafy greens exceeded guidance values; over half the vegetables exceeded the 95th percentile of market-basket concentrations for Pb. Vegetable Pb correlated with Al; soil particle adherence/incorporation was more important than Pb uptake via roots. Cd was similar to market-basket concentrations and below guidance values in nearly all samples. Vegetable Ba was much higher than Pb or Cd, although soil Ba was lower than soil Pb. The poor relationship between vegetable and soil metal concentrations is attributable to particulate contamination of vegetables and soil characteristics that influence phytoavailability. PMID:25163429

  16. Why is seed production so variable among individuals? A ten-year study with oaks reveals the importance of soil environment.

    Science.gov (United States)

    Pérez-Ramos, Ignacio M; Aponte, Cristina; García, Luis V; Padilla-Díaz, Carmen M; Marañón, Teodoro

    2014-01-01

    Mast-seeding species exhibit not only a large inter-annual variability in seed production but also considerable variability among individuals within the same year. However, very little is known about the causes and consequences for population dynamics of this potentially large between-individual variability. Here, we quantified seed production over ten consecutive years in two Mediterranean oak species - the deciduous Quercus canariensis and the evergreen Q. suber - that coexist in forests of southern Spain. First, we calibrated likelihood models to identify which abiotic and biotic variables best explain the magnitude (hereafter seed productivity) and temporal variation of seed production at the individual level (hereafter CVi), and infer whether reproductive effort results from the available soil resources for the plant or is primarily determined by selectively favoured strategies. Second, we explored the contribution of between-individual variability in seed production as a potential mechanism of satiation for predispersal seed predators. We found that Q. canariensis trees inhabiting moister and more fertile soils were more productive than those growing in more resource-limited sites. Regarding temporal variation, individuals of the two studied oak species inhabiting these resource-rich environments also exhibited larger values of CVi. Interestingly, we detected a satiating effect on granivorous insects at the tree level in Q. suber, which was evident in those years where between-individual variability in acorn production was higher. These findings suggest that individual seed production (both in terms of seed productivity and inter-annual variability) is strongly dependent on soil resource heterogeneity (at least for one of the two studied oak species) with potential repercussions for recruitment and population dynamics. However, other external factors (such as soil heterogeneity in pathogen abundance) or certain inherent characteristics of the tree might be

  17. Variability in responses of bacterial communities and nitrogen oxide emission to urea fertilization among various flooded paddy soils.

    Science.gov (United States)

    Wang, Ning; Ding, Long-Jun; Xu, Hui-Juan; Li, Hong-Bo; Su, Jian-Qiang; Zhu, Yong-Guan

    2015-03-01

    Fertilization affects bacterial communities and element biogeochemical cycling in flooded paddy soils and the effect might differ among soil types. In this study, five paddy soils from Southern China were subjected to urea addition to explore impacts of fertilization on nitrogen oxide (N2O) emission and bacterial community composition under the flooding condition. 16S rRNA gene-based illumina sequencing showed no obvious shifts in bacterial community composition of five soils after urea addition. However, some genera were affected by fertilization addition and the influenced genera varied among soils. During the late period (day 8-19) of flooding incubation without urea addition, N2O emission rates were elevated for all soils. However, urea effects on N2O emission were different among flooded soils. For soils where nirS and nirK gene abundances increased with urea addition, N2O emission was significantly increased compared to control treatment. Redundancy analysis showed that dissolved organic carbon, ammonium (NH4 (+)), ferrous iron (Fe(2+)) and nitrate (NO3 (-)) in pore water explained 33.4% of the variation in soil bacterial community composition, implying that urea regimes influenced the relative abundance of some bacterial populations possibly by regulating soil characteristics and then influencing N2O emission. These results provided insights into soil type-dependent effect of fertilization on the overall bacterial communities and nitrogen oxide emission in flooded paddy soils. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Assessment of soil strength variability in a havested loblolly pine plantation in the Piedmont region of Alabama, United States

    Science.gov (United States)

    Emily Carter; Tim McDonald; John Torbert

    2000-01-01

    Mechanised forest harvest operations are a significant source of soil compaction for which intensive tillage is prescribed to alleviate soil compaction and ensure successful regeneration of planted pine trees. Soil strength is a poiential indicator of compaction status of a harvest tract due to its sensitivity and the ease of data collection with a cone penetrometer,...

  19. A modeling approach to assess the hydrological response of small mediterranean catchments to the variability of soil characteristics in a context of extreme events

    Directory of Open Access Journals (Sweden)

    C. Manus

    2009-02-01

    Full Text Available This paper presents a modeling study aiming at quantifying the possible impact of soil characteristics on the hydrological response of small ungauged catchments in a context of extreme events. The study focuses on the September 2002 event in the Gard region (South-Eastern France, which led to catastrophic flash-floods. The proposed modeling approach is able to take into account rainfall variability and soil profiles variability. Its spatial discretization is determined using Digital Elevation Model (DEM and a soil map. The model computes infiltration, ponding and vertical soil water distribution, as well as river discharge. In order to be applicable to ungauged catchments, the model is set up without any calibration and the soil parameter specification is based on an existing soil database. The model verification is based on a regional evaluation using 17 estimated discharges obtained from an extensive post-flood investigation. Thus, this approach provides a spatial view of the hydrological response across a large range of scales. To perform the simulations, radar rainfall estimations are used at a 1 km2 and 5 min resolution. To specify the soil hydraulic properties, two types of pedotransfer function (PTF are compared. It is shown that the PTF including information about soil structure reflects better the spatial variability that can be encountered in the field. The study is focused on four small ungauged catchments of less than 10 km2, which experienced casualties. Simulated specific peak discharges are found to be in agreement with estimations from a post-event in situ investigation. Examining the dynamics of simulated infiltration and saturation degrees, two different behaviors are shown which correspond to different runoff production mechanisms that could be encountered within catchments of less than 10 km2. They produce simulated runoff coefficients that evolve in time and highlight the variability of the

  20. Ensemble kalman filtering to perform data assimilation with soil water content probes and pedotransfer functions in modeling water flow in variably saturated soils

    Science.gov (United States)

    Data from modern soil water contents probes can be used for data assimilation in soil water flow modeling, i.e. continual correction of the flow model performance based on observations. The ensemble Kalman filter appears to be an appropriate method for that. The method requires estimates of the unce...

  1. Biodegradation of Alachlor in Liquid and Soil Cultures Under Variable Carbon and Nitrogen Sources by Bacterial Consortium Isolated from Corn Field Soil

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    Simin Nasseri

    2013-03-01

    Full Text Available Alachlor, an aniline herbicide widely used in corn production, is frequently detected in water resources. The main objectives of this research were focused on isolating bacterial consortium capable of alachlor biodegradation, assessing the effects of carbon and nitrogen sources on alachlor biodegradation and evaluating the feasibility of using bacterial consortium in soil culture. Kavar corn field soil with a long history of alachlor application in Fars province of Iran has been explored for their potential of alachlor biodegradation. The influence of different carbon compounds (glucose, sodium citrate, sucrose, starch and the combination of these compounds, the effect of nitrogen sources (ammonium nitrate and urea and different pH (5.5-8.5 on alachlor removal efficiency by the bacterial consortium in liquid culture were investigated. After a multi-step enrichment program 100 days of acclimation, a culture with the high capability of alachlor degradation was obtained (63%. Glucose and sodium citrate had the highest alachlor reduction rate (85%. Alachlor reduction rate increased more rapidly by the addition of ammonium nitrate (94% compare to urea. Based on the data obtained in the present study, pH of 7.5 is optimal for alachlor biodegradation. After 30 days of incubation, the percent of alachlor reduction were significantly enhanced in the inoculated soils (74% as compared to uninoculated control soils (17.67% at the soil moisture content of 25%. In conclusion, bioaugmentation of soil with bacterial consortium may enhance the rate of alachlor degradation in a polluted soil.

  2. Using environmental variables and soil processes to forecast denitrification potential and nitrous oxide fluxes in coastal plain wetlands across different land uses

    Science.gov (United States)

    Morse, Jennifer L.; Ardón, Marcelo; Bernhardt, Emily S.

    2012-06-01

    We examined relationships between denitrification (DNF) and nitrous oxide (N2O) fluxes and potentially important chemical and physical predictors to build a predictive understanding of gaseous N losses from coastal plain wetlands. We collected soil, gas, and pore water samples from 48 sampling locations across a large (440 ha) restored wetland, an adjacent drained agricultural field, and nearby forested wetlands every two months over two years. In summer and fall 2007, we measured soil DNF potential (21.6-3560 mg N m-3 d-1) and N2O efflux (-4.36-8.81 mg N m-2 d-1), along with 17 predictor variables. We developed statistical models for the most comprehensive subset of the data set (fall 2007) and used another subset (summer 2007) for cross-validation. Soil pH and total soil nitrogen were the best predictors of DNF potential (Radj2 = 0.68). A regression using carbon dioxide flux and soil temperature together with soil extractable NH4+ and DNF potential explained 85% of the variation in fall N2O fluxes. The model for DNF performed reasonably well when cross-validated with summer data (R2 = 0.40), while the N2O model did not predict summer N2O fluxes (R2 wetland N2O effluxes will require finer-scale models that incorporate seasonal dynamics.

  3. Variability of apparently homogeneous soilscapes in São Paulo state, Brazil: II. quality of soil maps

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    M. van Den Berg

    2000-06-01

    Full Text Available The quality of semi-detailed (scale 1:100.000 soil maps and the utility of a taxonomically based legend were assessed by studying 33 apparently homogeneous fields with strongly weathered soils in two regions in São Paulo State: Araras and Assis. An independent data set of 395 auger sites was used to determine purity of soil mapping units and analysis of variance within and between mapping units and soil classification units. Twenty three soil profiles were studied in detail. The studied soil maps have a high purity for some legend criteria, such as B horizon type (> 90% and soil texture class (> 80%. The purity for the "trophic character" (eutrophic, dystrophic, allic was only 55% in Assis. It was 88% in Araras, where many soil units had been mapped as associations. In both regions, the base status of clay-textured soils was generally better than suggested by the maps. Analysis of variance showed that mapping was successful for "durable" soil characteristics such as clay content (> 80% of variance explained and cation exchange capacity (≥ 50% of variance explained of 0-20 and 60-80 cm layers. For soil characteristics that are easily modified by management, such as base saturation of the 0-20 cm layer, the maps had explained very little ( 100 m; (b taking advantage of correlations between easily measured soil characteristics and chemical soil properties and, (c unbending the link between legend criteria and a taxonomic system. The maps are well suited to obtain an impression of land suitability for high-input farming. Additional field work and data on former land use/management are necessary for the evaluation of chemical properties of surface horizons.

  4. Analyzing spatial variability of soil properties in the urban park before and after reconstruction to support decision-making in landscaping

    Science.gov (United States)

    Romzaikina, Olga; Vasenev, Viacheslav; Khakimova, Rita

    2017-04-01

    On-going urbanization stresses a necessity for structural and aesthetically organized urban landscapes to improve citizen's life quality. Urban soils and vegetation are the main components of urban ecosystems. Urban greenery regulates the climate, controls and air quality and supports biodiversity in urban areas. Soils play a key role in supporting urban greenery. However, soils of urban parks also perform other important environmental functions. Urban soils are influenced by a variety of environmental and anthropogenic factors and, in the result, are highly heterogeneous and dynamic. Reconstructions of green zones and urban parks, usually occurring in cities, alter soil properties. Analyzing spatial variability and dynamics of soil properties is important to support decision-making in landscaping. Therefore, the research aimed to analyze the spatial distribution of the key soil properties (acidity, soil organic carbon (SOC) and nutrient contents) in the urban park before and after reconstruction to support decision-making in selecting ornamental plants for landscaping. The research was conducted in the urban park named after Artyom Borovik in Moscow before (2012) and after (2014) the reconstruction. Urban soil's properties maps for both periods were created by interpolation of the field data. The observed urban soils included recreazems, urbanozems and constuctozems. Before the reconstruction soils were sampled using the uniform design (the net with 100 m side and key plots with 50m size). After the reconstructions the additional samples were collected at locations, where the land cover and functional zones changed in a result of the reconstruction.We sample from the depths 0-30, 30-50 and 50-100 cm. The following soil properties were measured: pH, SOC, K2O and P2O5. The maps of the analyzed properties were developed using open QGIS2.4 software by IDW. The vegetation in the park was examined using the scale of the visual assessment. The results of the visual

  5. Spatial variability of soil N2O and CO2 fluxes in different topographic positions in a tropical montane forest in Kenya

    Science.gov (United States)

    Arias-Navarro, C.; Díaz-Pinés, E.; Klatt, S.; Brandt, P.; Rufino, M. C.; Butterbach-Bahl, K.; Verchot, L. V.

    2017-03-01

    Quantifying and understanding the small-scale variability of nitrous oxide (N2O) and carbon dioxide (CO2) emission are essential for reporting accurate ecosystem greenhouse gas budgets. The objective of this study was to evaluate the spatial pattern of soil CO2 and N2O emissions and their relation to topography in a tropical montane forest. We measured fluxes of N2O and CO2 from 810 sampling locations across valley bottom, midslope, and ridgetop positions under controlled laboratory conditions. We further calculated the minimum number of samples necessary to provide best estimates of soil N2O and CO2 fluxes at the plot level. Topography exhibited a major influence on N2O emissions, with soils at midslope position emitting significantly less than at ridgetops and valley bottoms, but no consistent effect of topography on soil CO2 emissions was found. The high spatial variation of N2O and CO2 fluxes was further increased by changes in vegetation and soil properties resulting from human disturbance associated with charcoal production. Soil N2O and CO2 fluxes showed no spatial pattern at the plot level, with "hot spots" strongly contributing to the total emissions (10% of the soil cores represented 73 and 50% of the total N2O and CO2 emissions, respectively). Thus, a large number of samples are needed to obtain robust estimates of N2O and CO2 fluxes. Our results highlight the complex biogeochemical cycling in tropical montane forests, and the need to carefully address it in research experiments to robustly estimate soil CO2 and N2O fluxes at the ecosystem scale.

  6. Evaluating the role of soil variability on groundwater pollution and recharge at regional scale by integrating a process-based vadose zone model in a stochastic approach

    Science.gov (United States)

    Coppola, Antonio; Comegna, Alessandro; Dragonetti, Giovanna; Lamaddalena, Nicola; Zdruli, Pandi

    2013-04-01

    Interpreting and predicting the evolution of water resources and soils at regional scale are continuing challenges for natural scientists. Examples include non-point source (NPS) pollution of soil and surface and subsurface water from agricultural chemicals and pathogens, as well as overexploitation of groundwater resources. The presence and build up of NPS pollutants may be harmful for both soil and groundwater resources. The accumulation of salts and trace elements in soils can significantly impact crop productivity, while loading of salts, nitrates, trace elements and pesticides into groundwater supplies can deteriorate a source of drinking and irrigation water. Consequently, predicting the spatial distribution and fate of NPS pollutants in soils at applicative scales is now considered crucial for maintaining the fragile balance between crop productivity and the negative environmental impacts of NPS pollutants, which is a basis of sustainable agriculture. Soil scientists and hydrologists are regularly asked to assist state agencies to understand these critical environmental issues. The most frequent inquiries are related to the development of mathematical models needed for analyzing the impacts of alternative land-use and best management use and management of soil and water resources. Different modelling solutions exist, mainly differing on the role of the vadose zone and its horizontal and vertical variability in the predictive models. The vadose zone (the region from the soil surface to the groundwater surface) is a complex physical, chemical and biological ecosystem that controls the passage of NPS pollutants from the soil surface where they have been deposited or accumulated due to agricultural activities, to groundwater. Physically based distributed hydrological models require the internal variability of the vadose zone be explored at a variety of scales. The equations describing fluxes and storage of water and solutes in the unsaturated zone used in these

  7. A Top-down soil moisture and sap flux sampling design to capture the effect of inter-annual climate variability on ecohydrology in mountain catchments

    Science.gov (United States)

    Son, K.; Tague, C.

    2010-12-01

    Soil moisture in mountain catchments is highly spatial heterogeneous due to steep topographic gradients, complex soil and vegetation patterns and seasonally varying energy and precipitation inputs. In an idealized setting, a randomized soil moisture sampling design with high spatial frequency can be used to resolve the spatial heterogeneity of soil moisture at catchment scales. However, this bottom-up approach is constrained by the feasibility of high frequency measurements particularly in mountain environments with limited accessibility. Thus, in these mountain environments, an alternative, top-down approach is often needed. In this study, we propose the top-down approach sampling design of soil moisture and sapflux measurement based on an ecohydrologic model and clustering analysis. The sampling strategy is explicitly designed to capture the effect of inter-annual climate variability on ecohydrolgy response of mountain catchments located in King River Experiment Watersheds, Sierra National Forest. The ecohydrolgic model (RHESSys model) is calibrated with existing collected data sets including snow depth, soil moisture, sapflux, evapotranspiration from a flux tower and streamflow. The model is used to generate spatial-temporal patterns of snow accumulation and melt, soil moisture and transpiration and compute inter-annual mean and coefficient of variation of five hydrologic similarity indices. Similarity indices are chosen to reflect seasonal trajectories of snowmelt, root-zone soil moisture storage and evapotranspiration. Clustering analysis, using Partitioning Around Medoid (PAM), is used to partition the watershed based on these similarity indices. For the Kings River Experimental Watersheds, clustering distinguished six clusters and a representative plot per cluster. These results were used to identify additional strategic sampling points within the watershed. For each of these points, we installed soil moisture sensors (5TE) at the two depths (30m and 90m

  8. A comparison of interpolation methods for predicting spatial variability of soil organic matter content in Eastern Croatia

    Science.gov (United States)

    Đurđević, Boris; Jug, Irena; Jug, Danijel; Vukadinović, Vesna; Bogunović, Igor; Brozović, Bojana; Stipešević, Bojan

    2017-04-01

    Soil organic matter (SOM) plays crucial role in soil health and productivity and represents one of the key functions for determining soil degradation and soil suitability for crop production. Nowadays, continuing decline of organic matter in soils in agroecosystems, due to inappropriate agricultural practice (burning and removal of crop residue, overgrazing, inappropriate tillage, etc.) and environmental conditions (climate change, extreme weather conditions, erosion) leads to devastating soil degradation processes and decreases soil productivity. The main objectives of this research is to compare three different interpolation methods (Inverse Distance Weighting IDW, Ordinary kriging OK and Empirical Bayesian Kriging EBK) and provide best spatial predictor in order to ensure detailed analysis of the agricultural land in Osijek-Baranja County, Croatia. A number of 9,099 soil samples have been compiled from layer 0-30 cm and analyzed in laboratory. The average value of SOM in the study area was 2.66%, while 70.7 % of samples had SOM value below 3% in Osijek-Baranja County. Among the applied methods, the lowest root mean square error was recorded under Empirical Bayesian Kriging method which had most accurately assessed soil organic matter. The main advantage of EBK is that the process of creating a valid kriging model is automated so the manual parameter adjusting is eliminated, and this resulted with reduced uncertainty of EBK model. Conducted interpolation and visualization of data showed that 85.7% of agricultural land in Osijek-Baranja County has SOM content lower than 3%, which may indicate some sort of soil degradation process. By using interpolation methods combined with visualization of data, we can detect problematic areas much easier and with additional analysis, suggest measures to repair degraded soils. This kind of approach to problem solving in agriculture can be applied on various agroecological conditions and can significantly facilitate and

  9. Long-term landscape - land use interactions as explaining factor for soil organic matter variability in Dutch agricultural landscapes

    NARCIS (Netherlands)

    Schulp, C.J.E.; Veldkamp, A.

    2008-01-01

    The present-day land use pattern is often used for estimating soil organic matter pools. Although the effect of historical land use on soil organic matter (SOM) pools is often recognized, this factor is never accounted for in large-scale SOM inventories. We assessed if an inventory of long-term

  10. Irrigation scenarios for artichokes and dry bean as a result of soil variability on the basis of resistivity mapping in southwest Italy

    Directory of Open Access Journals (Sweden)

    Alaa Aldin Alromeed

    2015-09-01

    Full Text Available This work aims at comparing irrigation strategies on the basis of deficit irrigation and soil spatial variability assessed through electrical resistivity mapping (ERM conducted by an automatic resistivity profiler on-the-go sensor. Profiles chosen along a range of soil electrical resistivity showed different soil properties linked to water holding capacity within a field, with total available water (TAW values of the coarser-textured zone corresponding to about 50% of TAW in the finertextured zone within the field. Multi-year weather data were obtained on a daily basis and scenarios were developed for climatic demand conditions representing dry average and wet years. The ISAREG water balance and irrigation scheduling model was afterwards applied to the different soil profiles and with different strategies for full and deficit irrigation, to compute water and irrigation requirements as well as related yield impacts of deficit irrigation for artichokes and dry beans. Deficit irrigation allowed calculated water savings up to about 50% for the winter crop and 33% for the summer crop with yield losses lower than 10%. Irrigation requirements within irrigation strategy were 10 to 44% different between profiles, and this indicates that soil visualization techniques such as ERM can be used for the identification of zones for site-specific irrigation management.

  11. Diversity among strains of Pseudomonas aeruginosa from manure and soil, evaluated by multiple locus variable number tandem repeat analysis and antibiotic resistance profiles.

    Science.gov (United States)

    Youenou, Benjamin; Brothier, Elisabeth; Nazaret, Sylvie

    2014-01-01

    The results of a multiple locus variable number of tandem repeat (VNTR) analysis (MLVA)-based study designed to understand the genetic diversity of soil and manure-borne Pseudomonas aeruginosa isolates, and the relationship between these isolates and a set of clinical and environmental isolates, are hereby reported. Fifteen described VNTR markers were first selected, and 62 isolates recovered from agricultural and industrial soils in France and Burkina Faso, and from cattle and horse manure, along with 26 snake-related isolates and 17 environmental and clinical isolates from international collections, were genotyped. Following a comparison with previously published 9-marker MLVA schemes, an optimal 13-marker MLVA scheme (MLVA13-Lyon) was identified that was found to be the most efficient, as it showed high typability (90%) and high discriminatory power (0.987). A comparison of MLVA with PFGE for typing of the snake-related isolates confirmed the MLVA13-Lyon scheme to be a robust method for quickly discriminating and inferring genetic relatedness among environmental isolates. The 62 isolates displayed wide diversity, since 41 MLVA types (i.e. MTs) were observed, with 26 MTs clustered in 10 MLVA clonal complexes (MCs). Three and eight MCs were found among soil and manure isolates, respectively. Only one MC contained both soil and manure-borne isolates. No common MC was observed between soil and manure-borne isolates and the snake-related or environmental and clinical isolates. Antibiotic resistance profiles were performed to determine a potential link between resistance properties and the selective pressure that might be present in the various habitats. Except for four soil and manure isolates resistant to ticarcillin and ticarcillin/clavulanic acid and one isolate from a hydrocarbon-contaminated soil resistant to imipenem, all environmental isolates showed wild-type antibiotic profiles. Copyright © 2013 Institut Pasteur. Published by Elsevier Masson SAS. All rights

  12. Modelling large-scale spatial variability of soil properties with sequential stochastic simulation conditioned by universal kriging in a Hungarian study site

    Science.gov (United States)

    Szatmári, Gábor; Barta, Károly; Pásztor, László

    2015-04-01

    Modelling of large-scale spatial variability of soil properties is a promising subject in soil science, as well as in general environmental research, since the resulted model(s) can be applied to solve various problems. In addition to "purely" map an environmental element, the spatial uncertainty of the map product can deduced, specific areas could be identified and/or delineated (contaminated or endangered regions, plots for fertilization, etc.). Geostatistics, which can be regarded as a subset of statistics specialized in analysis and interpretation of geographically referenced data, offer a huge amount of tools to solve these tasks. Numerous spatial modeling methods have been developed in the past decades based on the regionalized variable theory. One of these techniques is sequential stochastic simulation, which can be conditioned with universal kriging (also referred to as regression kriging). As opposed to universal kriging (UK), sequential simulation conditioned with universal kriging (SSUK) provides not just one but several alternative and equally probable "maps", i.e. realizations. The realizations reproduce the global statistics (e.g. sample histogram, variogram), i.e. they reflect/model the reality in a certain global (and not local!) sense. In this paper we present and test SSUK developed in R-code and its utilizations in a water erosion affected study area. Furthermore, we compare the results from UK and SSUK. For this purpose, two soil variables were selected: soil organic matter (SOM) content and rooting depth (RD). SSUK approach is illustrated with a legacy soil dataset from a study area endangered by water erosion in Central Hungary. Legacy soil data was collected in the end of the 1980s in the framework of the National Land Evaluation Programme. Spatially exhaustive covariates were derived from a digital elevation model and from the land-use-map of the study area. SSUK was built upon a UK prediction system for both variables and 200 realizations

  13. Variabilidad espacial y diaria del contenido de humedad en el suelo en tres sistemas agroforestales Spatial and daily variability of soil moisture content in three agroforestry systems

    Directory of Open Access Journals (Sweden)

    Mariela Rivera Peña

    2009-04-01

    Full Text Available En seis puntos de tres transectos (102 m paralelos (9 m en tres sistemas de uso del terreno (Quesungual menor de dos años, SAQThe objective of this study was to determine the level of soil spatial variability in an area consisting of the land uses: Quesungual slash and mulch agroforestry system with less than two years (QSMAS<2, Slash-and-burn traditional system (SB and Secondary forest (SF. Soil samples were taken in three parallel transects of 102 m in length, separated 9 meters. The profile was sampled in the depths from 0 to 5 cm, 5 to 10 cm, 10 to 20 cm and 20 to 40 cm in 6 points (09, 11 am and 05 during 9 days. Coefficient of variation for soil properties varied for bulk density (0.76 and 15.1%, organic carbon (30.4 and 54.3%, volumetric moisture (9.5 and 23.5%, sand (12.8 and 22.5% and clay (14.0 and 29.2%. The geo-statistical analysis showed that the random component of the spatial dependence was predominant over the nugget effect. The functions of semivariograms, structured for each variable were used to generate maps of interpolated contours at a fine scale. The Moran (I autocorrelation indicated that sampling ranges less than 9 m would be adequate to detect spatial structure of the volumetric moisture variable.

  14. Different types of nitrogen deposition show variable effects on the soil carbon cycle process of temperate forests.

    Science.gov (United States)

    Du, Yuhan; Guo, Peng; Liu, Jianqiu; Wang, Chunyu; Yang, Ning; Jiao, Zhenxia

    2014-10-01

    Nitrogen (N) deposition significantly affects the soil carbon (C) cycle process of forests. However, the influence of different types of N on it still remained unclear. In this work, ammonium nitrate was selected as an inorganic N (IN) source, while urea and glycine were chosen as organic N (ON) sources. Different ratios of IN to ON (1 : 4, 2 : 3, 3 : 2, 4 : 1, and 5 : 0) were mixed with equal total amounts and then used to fertilize temperate forest soils for 2 years. Results showed that IN deposition inhibited soil C cycle processes, such as soil respiration, soil organic C decomposition, and enzymatic activities, and induced the accumulation of recalcitrant organic C. By contrast, ON deposition promoted these processes. Addition of ON also resulted in accelerated transformation of recalcitrant compounds into labile compounds and increased CO2 efflux. Meanwhile, greater ON deposition may convert C sequestration in forest soils into C source. These results indicated the importance of the IN to ON ratio in controlling the soil C cycle, which can consequently change the ecological effect of N deposition. © 2014 John Wiley & Sons Ltd.

  15. Variabilidade espacial de atributos físicos do solo em uma microbacia hidrográfica Spatial variability of soil physical atribbutes in small watershed

    Directory of Open Access Journals (Sweden)

    Vinicius Augusto da Silveira Vieira

    2007-10-01

    Full Text Available A variabilidade espacial dos atributos físicos do solo é importante para a caracterização do comportamento espacial dos solos em bacias hidrográficas. Objetivou-se com este trabalho estudar a variabilidade espacial de atributos físicos do solo em uma microbacia hidrográfica, visando subsidiar estudos de manejo do solo e da água. A área em estudo é uma microbacia que pode ser considerada homogênea para estudos com agentes erosivos, como a precipitação, devido ao tamanho reduzido (1,23 ha, mas de grande variabilidade de respostas à erosão, em função dos atributos do solo, vegetação, histórico de uso e relevo. Com o auxílio de SIG, DGPS e estação total, toda área foi dividida em grid retangular de 20 m, onde o solo foi amostrado em duas camadas, 0 a 20 cm e 20 a 40 cm. Os atributos avaliados foram: teores de areia, silte e argila e argila dispersa em água (ADA. Os resultados foram analisados utilizando-se a estatística básica, como histogramas e assimetria, e geoestatística, por meio de semivariogramas e mapas de krigagem. Houve dependência espacial de todos os atributos analisados, especialmente na camada de 20 a 40 cm.The spatial variability of physical attributes in the soil is of great importance for soil and water management practices. This work aimed at to study the spatial variability of soil physical attributes in a small watershed, in order to evaluate the management of soil and water. The watershed area is considered homogenious, based on erosive agents, such as rainfall, due to its small area (1,23 ha, and it shows variability of soil properties, concerning vegetation, land use, and topography. GIS, DGPS and total station were used to set up a grid of 20x20 m. Soil were sampled from 0 to 20 cm and 20 to 40 cm layers. Amount of sandy, silt, clay and water dispersible clay were evaluated. The data were compared in histograms, coefficient of simetry, and geostatistical analyses expressed by semivariograms and

  16. Spatial variability in soil organic carbon in a tropical montane landscape: associations between soil organic carbon and land use, soil properties, vegetation, and topography vary across plot to landscape scales

    Directory of Open Access Journals (Sweden)

    M. de Blécourt

    2017-08-01

    Full Text Available Presently, the lack of data on soil organic carbon (SOC stocks in relation to land-use types and biophysical characteristics prevents reliable estimates of ecosystem carbon stocks in montane landscapes of mainland SE Asia. Our study, conducted in a 10 000 ha landscape in Xishuangbanna, SW China, aimed at assessing the spatial variability in SOC concentrations and stocks, as well as the relationships of SOC with land-use types, soil properties, vegetation characteristics and topographical attributes at three spatial scales: (1 land-use types within a landscape (10 000 ha, (2 sampling plots (1 ha nested within land-use types (plot distances ranging between 0.5 and 12 km, and (3 subplots (10 m radius nested within sampling plots. We sampled 27 one-hectare plots – 10 plots in mature forests, 11 plots in regenerating or highly disturbed forests, and 6 plots in open land including tea plantations and grasslands. We used a sampling design with a hierarchical structure. The landscape was first classified according to land-use types. Within each land-use type, sampling plots were randomly selected, and within each plot we sampled within nine subplots. SOC concentrations and stocks did not differ significantly across the four land-use types. However, within the open-land category, SOC concentrations and stocks in grasslands were higher than in tea plantations (P < 0.01 for 0–0.15 m, P = 0.05 for 0.15–0.30 m, P = 0.06 for 0–0.9 m depth. The SOC stocks to a depth of 0.9 m were 177.6 ± 19.6 (SE Mg C ha−1 in tea plantations, 199.5 ± 14.8 Mg C ha−1 in regenerating or highly disturbed forests, 228.6 ± 19.7 Mg C ha−1 in mature forests, and 236.2 ± 13.7 Mg C ha−1 in grasslands. In this montane landscape, variability within plots accounted for more than 50 % of the overall variance in SOC stocks to a depth of 0.9 m and the topsoil SOC concentrations. The

  17. Small scale spatial variability and pattern of soil respiration and water content in wet and a dry temperate grasslands and bare soil

    Czech Academy of Sciences Publication Activity Database

    Fóti, S.; Nagy, Z.; Balogh, J.; Bartha, S.; Acosta, Manuel; Czóbel, S.; Péli, E.; Marek, Michal V.; Tuba, Z.

    2009-01-01

    Roč. 28, č. 4 (2009), s. 389-398 ISSN 1335-342X Institutional research plan: CEZ:AV0Z60870520 Institutional support: RVO:67179843 Keywords : chamber technique * coefficient of variation * semivariance * Soil respiration * spatial pattern Subject RIV: EH - Ecology, Behaviour

  18. Short-term variability in labile soil phosphorus is positively related to soil moisture in a humid tropical forest in Puerto Rico

    Science.gov (United States)

    Tana E. Wood; Danielle Matthews; Karen Vandecar; Deborah Lawrence

    2016-01-01

    Primary productivity in tropical forests is often considered limited by phosphorus (P) availability. Microbial activity is a key regulator of available P through organic matter decomposition (supply) as well as microbial immobilization (depletion). Environmental conditions, such as soil moisture and temperature can fluctuate...

  19. Spatial Variability of Soil Moisture and the Validation of Remote Sensing Products in a Unique Beach Environment

    Science.gov (United States)

    Rogers, J.; Berg, A. A.

    2010-12-01

    Soil water conditions are crucial for understanding the exchange of energy and mass at the earth's surface. The need for a better description of the heterogeneity of surface soil moisture in both space and time has garnered interest from areas including agricultural management and drought monitoring, water resources and flood prediction, and more recently climate modeling. Soil moisture has also been identified as a critical parameter in the initiation of particle entrainment by wind due to the alteration of physical properties such as aggregate structure and inter-particle cohesion. Therefore the dynamics of soil moisture are of great interest for regional wind erosion modeling as well as for the development of agricultural productivity and soil loss models. In this study, a unique environment for the study of soil moisture was investigated at Williston Reservoir in Northern British Columbia, Canada. For a period of a month or more before the reservoir is filled by the spring melt, several thousand hectares of fine-grained sediments are exposed to wind causing significant erosion and therefore potential air quality concerns. Here we present a study of the spatial and temporal patterning of surface soil moisture in exposed sediments. Measurements at small scales are used in the validation of remote sensing products at large scales and these estimates have been implemented into blowing dust models. Active microwave (RADARSAT-2) and optical (LandSAT-5) scenes were obtained between May 24th - June 2nd, 2009. On the ground, point measurements using capacitance based probes were performed over 4 test plots coincident with satellite overpass. Areal averages of soil moisture collected on the ground are used in the validation of soil moisture estimates from four backscatter inversion models (microwave) and a thermal band mono-window brightness temperature algorithm (optical). The studied environment represents an important validity test because backscatter inversion models

  20. Cellulose and hemicellulose decomposition by forest soil bacteria proceeds by the action of structurally variable enzymatic systems

    OpenAIRE

    Rubén López-Mondéjar; Daniela Zühlke; Dörte Becher; Katharina Riedel; Petr Baldrian

    2016-01-01

    Evidence shows that bacteria contribute actively to the decomposition of cellulose and hemicellulose in forest soil; however, their role in this process is still unclear. Here we performed the screening and identification of bacteria showing potential cellulolytic activity from litter and organic soil of a temperate oak forest. The genomes of three cellulolytic isolates previously described as abundant in this ecosystem were sequenced and their proteomes were characterized during the growth o...

  1. Surface features of soil particles of three types of soils under different land use strategies

    Science.gov (United States)

    Matveeva, Nataliy; Kotelnikova, Anna; Rogova, Olga; Proskurnin, Mikhail

    2017-04-01

    Nowadays, there is a clear need in a deep investigation of molecular composition of soils and of its influence on surface characteristics of soil particles. The aim of this study is to evaluate the composition and properties of physical fractions in different soil types in determining functional specificity of soil solid-phase surface. The experiments were carried out with three different types of Russian soils—Sod-Podzolic, Chestnut, and Chernozem soils—under various treatments (fallow, different doses of mineral fertilizers and their aftereffects). The samples were separated into three fractions: silt (SF) with a particle size of 2 μm and the density >2 g/cm3. We measured specific surface area, surface hydrophobicity (contact angle, CA), ζ-potential, and the point of zero charge (PZC). For Chernozem and Chestnut soils and their fractions of we observed an increase in hydrophobicity for SF and RF under fertilizer treatment. At the sites not treated with fertilizers and aftereffect sites, the hydrophobicity of fractions was lower compared to the sites under treatment. The CA of the original soils and fractions were different: in 35% of cases CA was higher for SF and RF by 12-16%. The rest of samples demonstrated CA of all three physical fractions lower than CA of the original soil. The variability of the mean CA indicates considerable differences in ζ-potential and PZC between different types of soils and soil fractions. The results of potentiometric titration of PZC for Sod-Podzolic soil showed that all values are in acidic range, which suggests predominance of acidic functional groups at the surface of soil particles. Specific surface area determines soil sorption processes, bioavailability of nutrients, water etc. Here, specific surface area of Sod-Podzolic soil was low and SF-dependent. We calculated specific surface charge from obtained data on specific surface area and PZC. The results suggested considerable differences between sorption features of

  2. Quantitative physical and chemical variables used to assess erosion and fertility loss in tropical Dominican and Haitian soils

    Science.gov (United States)

    Pastor, J.; Alexis, S.; Vizcayno, C.; Hernández, A. J.

    2009-04-01

    The Pedernales province (Dominican Republic) has the main part of the only Biosphere Reserve in that Caribbean Island, including the Bahoruco and Jaragua National Parks. In these Parks is possible to find almost the totality of tropical forest ecosystems (evergreen rain forest, latifoliated forest, dry forest and mangrove forest on mainland), as well as the most frequent soil uses in the Dominican country. The consulted bibliography about the soils is very scarce and it does not give any information relating to this natural resource, which is basic for a sustainable development management in this territory. When Christopher Columbus reached the island, its plant cover constituted 95% of the land. This was largely because the limited, rudimentary tools used by the Indians to exploit the soil, allowed them to maintain a well-balanced ecological system. The initial type of agriculture practised by the indigenous inhabitants was scarcely destructive and based on vegetatively reproducing crops propagated through cuttings, but later forest burning was an especially significant management practice aimed at releasing nutrients into the soil, in an environment in which under natural conditions, particularly those of the rainforest, these were mostly locked within plant structures. The colonial system, on the contrary, brought with it more elaborate methods and utensils enabling them to cultivate cereals (somewhat unknown to the native Indians) and to rear livestock (cows, goats) yet contributed to the growth of deforestation. Agricultural activities were not confined to the plains; even the virgin woods of the mountains were exploited. The monocrops grown across vast expanses rapidly rid the soil of its productive capacity. Cutting down and burning forest for agricultural uses, and also industrial exploitation of bauxite and limestone produced also important alterations in the soil processes. Agricultural activities were not confined to the plains; even the virgin woods of

  3. Componentes principais como preditores no mapeamento digital de classes de solos Principal components as predictor variables in digital mapping of soil classes

    Directory of Open Access Journals (Sweden)

    Alexandre ten Caten

    2011-07-01

    Full Text Available Tecnologias disponíveis para a observação da Terra oferecem uma grande gama de informações sobre componentes ambientais que, por estarem relacionadas com a formação dos solos, podem ser usadas como variáveis preditoras no Mapeamento Digital de Solos (MDS. No entanto, modelos com um grande número de preditores, bem como a existência de multicolinearidade entre os dados, podem ser ineficazes no mapeamento de classes e propriedades do solo. O objetivo deste estudo foi empregar a Análise de Componentes Principais (ACP visando a selecionar e diminuir o número de preditores na regressão logística múltipla multinomial (RLMM utilizada no mapeamento de classes de solos. Nove covariáveis ambientais, ligadas ao fator de formação relevo, foram derivadas de um Modelo Digital de Elevação e denominadas variáveis originais, estas foram submetidas à ACP e transformadas em Componentes Principais (CP. As RLMM foram desenvolvidas utilizando-se atributos de terreno e as CP como variáveis explicativas. O mapa de solos gerado a partir de três CP (65,6% da variância original obteve um índice kappa de 37,3%, inferior aos 48,5% alcançado pelo mapa de solos gerado a partir de todas as nove variáveis originais.Available technologies for Earth observation offer a wide range of predictors relevant to Digital Soil Mapping (DSM. However, models with a large number of predictors, as well as, the existence of multicollinearity among the data, may be ineffective in the mapping of classes and soil properties. The aim of this study was to use the Principal Component Analysis (PCA to reduce the number of predictors in the multinomial logistic regression (MLR used in soil mapping. Nine environmental covariates, related to the relief factor of soil formation, were derived from a digital elevation model and named the original variables, which were submitted to PCA and transformed into principal components (PC. The MLR were developed using the terrain

  4. Aqueous Iron-Sulfide Clusters in Variably Saturated Soil Systems: Implications for Iron Cycling and Fluid Flow

    Science.gov (United States)

    McGuire, J. T.; Hansen, D. J.; Mohanty, B. P.

    2008-12-01

    Iron and sulfur cycling is an important control on contaminant fate and transport, the availability of micronutrients and the physics of water flow. This study explores the effects of soil structure (i.e. layers, lenses, macropores, or fractures) on linked biogeochemical and hydrological processes involving Fe and S cycling in the vadose zone using packed soil columns. Three laboratory soil columns were constructed: a homogenized medium-grained sand, homogenized organic-rich loam, and a sand-over-loam layered column. Both upward and downward infiltration of water was evaluated during experiments to simulate rising water table and rainfall events respectively. Water samples extracted by lysimeter were analyzed for reduced species (including total sulfide, Fe(II), and FeSaq) voltammetrically using a mercury drop electrode. In addition to other reduced species, aqueous FeS clusters (FeSaq) were observed in two of the columns, with the greatest concentrations of FeSaq occurring in close proximity to the soil interface in the layered column. To our knowledge, this is the first documentation of aqueous FeS clusters in partially saturated sediments. The aqueous nature of FeSaq allows it to be transported instead of precipitating and suggests that current conceptual models of iron-sulfur cycling may need to be adapted to account for an aqueous phase. The presence of iron-rich soil aggregates near the soil interface may indicate that FeS clusters played a critical role in the formation of soil aggregates that subsequently caused up to an order of magnitude decrease in hydraulic conductivity.

  5. Factorial kriging and stepwise regression approach to identify environmental factors influencing spatial multi-scale variability of heavy metals in soils.

    Science.gov (United States)

    Lv, Jianshu; Liu, Yang; Zhang, Zulu; Dai, Jierui

    2013-10-15

    The knowledge about spatial variations of heavy metals in soils and their relationships with environmental factors is important for human impact assessment and soil management. Surface soils from Rizhao city, Eastern China with rapid urbanization and industrialization were analyzed for six key heavy metals and characterized by parent material and land use using GIS-based data. Factorial kriging analysis and stepwise multiple regression were applied to examine the scale-dependent relationships among heavy metals and to identify environmental factors affecting spatial variability at each spatial scale. Linear model of coregionalization fitting showed that spatial multi-scale variation of heavy metals in soils consisted of nugget effect, an exponential structure with the range of 12 km (short-range scale), as well as a spherical structure with the range of 36 km (long-range scale). The short-range variation of Cd, Pb and Zn were controlled by land use, with higher values in urban areas as well as cultivated land in mountain area, and were related to human influence; while parent material dominated the long structure variations of these elements. Spatial variations of Cr and Ni were associated with natural geochemical sources at short- and long-range scales. At both two scales, Hg dominated by land use, corresponded well to spatial distributions of urban areas, and was attributed to anthropic emissions and atmosphere deposition. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Modelling crop yield, soil organic C and P under variable long-term fertilizer management in China

    Science.gov (United States)

    Zhang, Jie; Xu, Guang; Xu, Minggang; Balkovič, Juraj; Azevedo, Ligia B.; Skalský, Rastislav; Wang, Jinzhou; Yu, Chaoqing

    2016-04-01

    Phosphorus (P) is a major limiting nutrient for plant growth. P, as a nonrenewable resource and the controlling factor of aquatic entrophication, is critical for food security and human future, and concerns sustainable resource use and environmental impacts. It is thus essential to find an integrated and effective approach to optimize phosphorus fertilizer application in the agro-ecosystem while maintaining crop yield and minimizing environmental risk. Crop P models have been used to simulate plant-soil interactions but are rarely validated with scattered long-term fertilizer control field experiments. We employed a process-based model named Environmental Policy Integrated Climate model (EPIC) to simulate grain yield, soil organic carbon (SOC) and soil available P based upon 8 field experiments in China with 11 years dataset, representing the typical Chinese soil types and agro-ecosystems of different regions. 4 treatments, including N, P, and K fertilizer (NPK), no fertilizer (CK), N and K fertilizer (NK) and N, P, K and manure (NPKM) were measured and modelled. A series of sensitivity tests were conducted to analyze the sensitivity of grain yields and soil available P to sequential fertilizer rates in typical humid, normal and drought years. Our results indicated that the EPIC model showed a significant agreement for simulating grain yields with R2=0.72, index of agreement (d)=0.87, modeling efficiency (EF)=0.68, pmanagement practices.

  7. Short-range variability of soil pH in a regional geochemical survey, communicating uncertainty to the data user

    Science.gov (United States)

    Ander, Louise; Knights, Kate; Lark, Murray

    2015-04-01

    The north of Ireland is well-furnished with geochemical data after completion of the Tellus survey of Northern Ireland and the Tellus Border survey of six northern counties of the Republic of Ireland. These data are of considerable interest to the agricultural sector, in particular the data on soil pH. However, a geochemical survey at regional scale cannot resolve significant variation of soil pH, in particular effects of soil management and fine-scale variation of superficial material. This leads to uncertainties in the mapped soil pH which must be accounted for when making decisions about management interventions, including more detailed local sampling. In this poster we show how uncertainty of predicted soil pH, relative to established threshold values, can be quantified by disjunctive kriging. The uncertainty is expressed in terms of probabilities. We show how this can be communicated to the data user by means of the calibrated phrases of the IPCC, using results from recent research on its efficacy to modify its presentation.

  8. Transport of ARS-labeled hydroxyapatite nanoparticles in saturated granular media is influenced by surface charge variability even in the presence of humic acid

    Science.gov (United States)

    Hydroxyapatite nanoparticles (nHAP) are increasingly being used to remediate soils and water polluted by metals and radionuclides. The transport and retention of Alizarin red S (ARS)-labeled nHAP in water-saturated granular media were investigated. Experiments were conducted over a range of ionic ...

  9. Variáveis relacionadas à estabilidade de complexos organo-minerais em solos tropicais e subtropicais brasileiros Selected soil-variables related to the stability of organo-minerals complexes in tropical and subtropical brazilian soils

    Directory of Open Access Journals (Sweden)

    Alberto Vasconcellos Inda Junior

    2007-10-01

    Full Text Available A estabilidade de complexos organo-minerais é uma característica importante quanto à química e física de solos tropicais e subtropicais. O objetivo deste estudo foi identificar variáveis relacionadas à estabilidade de complexos organo-minerais, avaliada pela energia de ultra-som necessária para a dispersão total do solo em partículas primárias, em seis solos das regiões Sul e Centro-Oeste do Brasil com textura e mineralogia distintas. A energia de ultra-som necessária para dispersão total dos solos variou de 239 a 2.389J mL-1, sendo diretamente relacionada aos teores de carbono orgânico (R²=0,799, PThe stability of organo-mineral complexes is an important characteristic related to the soil chemistry and physics of tropical and subtropical soils. This study was aimed at identifing the variables related to the stability of organo-mineral complexes, evaluated by ultrasonic energy necessary to complete soil dispersion, of six soils from South and West-Center regions of Brazil with distint texture and mineralogy. The ultrasonic energy to complete soil dispersion varied from 239 a 2389J mL-1, and was positively related to the soil organic carbon concentrations (R²=0.799, P<0.05. The clay mineralogy had an important role to the stability of organo-mineral complexes, which were related to the content of low cristalinity iron oxides (R²=0.586, P<0.10, but did not had relationship with the total pedogenic iron oxides. The qualitative analysis of the clay mineralogy, by X-ray diffraction, evidenced that gibbsite and goethite are the main clay minerals related to the stability of organo-mineral complexes, reinforcing the importance of these minerals on the physical protection and coloidal stability of the soil organic matter in the tropical and subtropical soils.

  10. Gis-approach for variability assessment of soil electric conductivity under pedoturbation activity of mole rat (Spalax microphthalmus

    Directory of Open Access Journals (Sweden)

    T. М. Konovalova

    2010-06-01

    Full Text Available The results of the investigation of the impact of the mole rat’s activity on soil electric conductivity have been presented. GIS-technology have been shown to be effective for assessment of the pedoturbation activity effect on the soil surface heterogeneity formation. Method of the one-dimension spatial coordinated array transformation into matrix form has been proposed for following multidimension statistic analysis application. The quantity estimation of the mole rats role in formation of the habitat nanorelief-level diversity has been obtained by means of indexes of the landscape complexity and diversity.

  11. The Importance of Deep Roots and Hydraulic Redistribution on Vegetation and Soil Responses to Hydro-Climatic Variability: A Simulation Analysis

    Science.gov (United States)

    Drewry, Darren; Kumar, Praveen; Sivapalan, Murugesu

    2010-05-01

    shortwave and longwave radiation regimes that drive photosynthesis, stomatal conductance and leaf energy balance in each layer, along with the canopy microclimate. The canopy component of the model is coupled to a multi-layer soil-root model that computes soil moisture and heat transport, root water uptake, and the passive redistribution of moisture across soil potential gradients by the root system. The below-ground model is based on a novel mechanistic formulation coupling soil moisture transport by the Richards' equation to root water uptake and hydraulic redistribution. Model skill in capturing the diurnal variability in canopy-atmosphere exchange is validated using eddy-covariance flux observations from a tower site in the Tapajos National Forest. A climate forcing record for the region provides a basis for simulating vegetation and soil responses to ENSO-driven drought conditions over the last several decades. Particular focus is placed on the impacts of deep rooting and HR on soil moisture persistence through the root zone and its role in regulating carbon uptake and energy partitioning by the vegetated land surface.

  12. Charge collection efficiency in SI GaAs grown from melts with variable composition as a material for solar neutrino detection

    CERN Document Server

    Verbitskaya, E; Ivanov, A; Strokan, N; Vasilev, V; Markov, A; Polyakov, A; Gavrin, V; Kozlova, Y; Veretenkin, E; Bowles, T J

    2000-01-01

    The results on electrical characteristics and charge collection efficiency in the detectors from bulk SI GaAs developed as a material for solar neutrino spectroscopy are presented. SI GaAs crystals were grown by the Czochralski method. The changes in the stoichiometric components are permanently controlled. It is shown that the performance of GaAs p sup + -i-n sup + structures provided the range of operational reverse voltage up to 1 kV. Measurement of deep level spectra and their analysis reveal the dominant deep levels - hole traps E sub v +0.51 and +0.075 eV in GaAs grown from stoichiometric and nonstoichiometric melts, respectively. Investigation of carrier transport properties and bulk homogeneity evinced in charge collection efficiency has shown advantageous results for SI GaAs grown from stoichiometric melt. The reduction of carrier transport parameters and charge collection efficiency in GaAs grown from nonstoichiometric melt is analyzed taking into consideration formation of the hole trap E sub v +0....

  13. Variability of Some soil physical and chemical properties along a transect under wind erosion processes in Segzi district, Isfahan

    Directory of Open Access Journals (Sweden)

    F. Ghiesari

    2016-10-01

    Full Text Available Introduction: Arid and semiarid environment is the main climatic condition in central Iran, as well as 80 million km 2 of Iran (> 50% is affected by wind erosion. During the last decades, the area affected by wind erosion and desertification processes has increased as a result of human activity, climate change and recent drought (Karimzadeh, 2001. Thus, it is crucial to control wind erosion in the arid regions of Iran as the most serious environmental problem. In this regard, the information on the rate of soil erosion is needed for developing management practices and making strategic decisions.. Soil erosion rate has increased as a result of improper gypsum and clay mining operations In the Segzi region of Isfahan,. coarsening of the soil texture (as a result of the loss of fine textured materials, depletion of soil organic matter and degeneration of vegetation are wind erosion damages occurred widely. The objective of this study was to estimate wind erosion rates with 137Cs technique, and also to determine changes in soil physical and chemical properties by wind erosion process, along the wind erosion transect across the Segzi district, east of Isfahan. Materials and Methods: This study was conducted in arid region of east of Isfahan Province. sixteen sites were selected along a northeast- southwest transect with 42 km length. Eighty soil samples were taken from 0-30 cm in 5 cm layer depth sections. Some physical and chemical properties were measured and a reference site with lowest rate of soil erosion and sedimentation was also studied. 137-Cs technique was used for determination of erosional and depositional sites. Analysis of variance was used to compare physical and chemical properties sites to reference site. Results and Discussion: The results showed that sites of 1 to 8, 10 and 12-16 were identified as erosional sites and two sites of 9 and 11 were recognized as depositional sites. Soil organic matter and total nitrogen contents were

  14. CHARGE IMBALANCE

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, John

    1980-09-01

    The purpose of this article is to review the theory of charge imbalance, and to discuss its relevance to a number of experimental situations. We introduce the concepts of quasiparticle charge and charge imbalance, and discuss the generation and detection of charge imbalance by tunneling. We describe the relaxation of the injected charge imbalance by inelastic scattering processes, and show how the Boltzmann equation can be solved to obtain the steady state quasiparticle distribution and the charge relaxation rate. Details are given of experiments to measure charge imbalance and the charge relaxation rate when inelastic scattering is the predominant relaxation mechanism. Experiments on and theories of other charge relaxation mechanisms are discussed, namely relaxation via elastic scattering in the presence of energy gap anisotropy, or in the presence of a pair breaking mechanism such as magnetic impurities or an applied supercurrent or magnetic field. We describe three other situations in which charge imbalance occurs, namely the resistance of the NS interface, phase slip centers, and the flow of a supercurrent in the presence of a temperature gradient.

  15. Spatial Variability of Plant Available Water, Soil Organic Carbon, and Microbial Biomass under Divergent Land Uses: A Comparison among Regression-Kriging, Cokriging, and Regression-Cokriging

    Science.gov (United States)

    Kiani, M.; Hernandez Ramirez, G.; Quideau, S.

    2016-12-01

    Improved knowledge about the spatial variability of plant available water (PAW), soil organic carbon (SOC), and microbial biomass carbon (MBC) as affected by land-use systems can underpin the identification and inventory of beneficial ecosystem good and services in both agricultural and wild lands. Little research has been done that addresses the spatial patterns of PAW, SOC, and MBC under different land use types at a field scale. Therefore, we collected 56 soil samples (5-10 cm depth increment), using a nested cyclic sampling design within both a native grassland (NG) site and an irrigated cultivated (IC) site located near Brooks, Alberta. Using classical statistical and geostatistical methods, we characterized the spatial heterogeneities of PAW, SOC, and MBC under NG and IC using several geostatistical methods such as ordinary kriging (OK), regression-kriging (RK), cokriging (COK), and regression-cokriging (RCOK). Converting the native grassland to irrigated cultivated land altered soil pore distribution by reducing macroporosity which led to lower saturated water content and half hydraulic conductivity in IC compared to NG. This conversion also decreased the relative abundance of gram-negative bacteria, while increasing both the proportion of gram-positive bacteria and MBC concentration. At both studied sites, the best fitted spatial model was Gaussian based on lower RSS and higher R2 as criteria. The IC had stronger degree of spatial dependence and longer range of spatial auto-correlation revealing a homogenization of the spatial variability of soil properties as a result of intensive, recurrent agricultural activities. Comparison of OK, RK, COK, and RCOK approaches indicated that cokriging method had the best performance demonstrating a profound improvement in the accuracy of spatial estimations of PAW, SOC, and MBC. It seems that the combination of terrain covariates such as elevation and depth-to-water with kriging techniques offers more capability for

  16. Effect of mine tailing on the spatial variability of soil nematodes from lead pollution in La Union (Spain).

    Science.gov (United States)

    Rodríguez Martín, José Antonio; Gutiérrez, Carmen; Escuer, Miguel; García-González, Ma Teresa; Campos-Herrera, Raquel; Aguila, Nancy

    2014-03-01

    The Cartagena-La Union mining district, exploited since the end of the 3rd century BC, was one of the world's largest lead producers in the 19th century. Although activity ceased in 1991, today mining residues pose a huge pollution problem. This study characterises lead contents (total and DPTA) and other soil parameters (N, P, K, pH, SOM, CaCO3, granulometric fraction, etc.) using multivariate geostatistical methods in relation to nematode diversity. In this work, trophic groups and metabolic footprints of soil nematodes were measured using 193 samples from the mining, natural and agricultural areas in this district. We explored the relationship between soil health and nematode communities. High lead concentrations were quantified: mean 8,500 mg kg(-1) for total and 340 mg kg(-1) for DPTA in this mining area. Although nematode diversity was broad (81 taxa), their diversity, abundance and metabolic footprints significantly reduced in the mining area. Significant differences in the nematode community structure were observed, and the relative abundance of predators was sensitive to mine and agricultural activities, whilst omnivores reduced only in the agricultural area, and bacterial feeders exhibited a differential response to both anthropogenic disturbances. The total abundance of nematodes, trophic groups and c-p groups correlated negatively with soil Pb contents, and a positive relationship was found with SOM and N, P and K contents. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Variable grain legume yields, responses to phosphorus and rotational effects on maize across soil fertility gradients on African smallholder farms

    NARCIS (Netherlands)

    Zingore, S.; Murwira, H.K.; Delve, R.J.; Giller, K.E.

    2008-01-01

    Promiscuous soyabean varieties have potential to contribute significantly to income generation, food security and soil N budgets on smallholder farms. One of the major factors limiting this potential is farmers¿ preference to allocate nutrient resources to food security cereal crops on the most

  18. Temporal variability of soil microbial communities after application of dicyandiamide-treated swine slurry and mineral fertilizers

    NARCIS (Netherlands)

    Suleiman, A.K.A.; Gonzatto, Rogerio; Aita, Celso; Lupatini, M.; Jacques, Rodrigo; Kuramae, E.E.; Antoniolli, Zaida; Roesch, Luiz

    2016-01-01

    In modern agriculture, mineral and organic fertilization account for most of the global anthropogenic N2O emissions. A strategy to prevent or to reduce emissions of greenhouse gases such as N2O is the use of nitrification inhibitors, which temporarily inhibit the microbial conversion of soil

  19. Single-charge craters excavated during subsurface high-explosive experiments at Big Black Test Site, Mississippi

    Energy Technology Data Exchange (ETDEWEB)

    Woodruff, W.R.; Bryan, J.B.

    1978-10-19

    Single-charge and row-charge subsurface cratering experiments were performed to learn how close-spacing enhances single-crater dimensions. Our first experimental phase established cratering curves for 60-lb charges of the chemical explosive. For the second phase, to be described in a subsequent report, the Row-cratering experiments were designed and executed. This data report contains excavated dimensions and auxiliary data for the single-charge cratering experiments. The dimensions for the row-charge experiments will be in the other report. Significant changes in the soil's water content appeared to cause a variability in the excavated dimensions. This variability clouded the interpretation and application of the cratering curves obtained.

  20. EVOLUTION OF SOIL CHEMICAL VARIABLES IN AN ORGANIC CELERY CROP DURING THE CONVERSION PERIOD TO ORGANIC FARMING

    Directory of Open Access Journals (Sweden)

    J.A. Sanchez-Romero

    2013-07-01

    Full Text Available For this study two fertilisation assays were carried out in an experimental field. The first assay (F1 used a sheep manure amendment, following the stipulations of European regulations concerning organic agriculture practices, and the second assay (F2 followed conventional agricultural practices of the area using inorganic fertilizers (313; 37 and 566 kgha-1 of N, P and K, respectively. Over a three-year period, samples of the arable soil layer were taken monthly in order to analyse the soil properties as indicators of soil quality (organic carbon, total Kjeldahl nitrogen, C:N ratio, Olsen P, electrical conductivity, pH in water and 1M KCl, cation exchangeable capacity, and exchangeable bases (Mg, K and Na. The experimental plot managed using organic agriculture techniques showed significantly better conditions for crop development than the conventionally managed plot: higher quantities of organic matter (22.4 and 17.4 gkg-1, respectively and nitrogen ( 3.0 and 2.5 gkg-1, respectively, a higher cation exchange capacity(14.4 and 12.2 cmol(+kg-1, respectively and greater availability of phosphorus ( 45.4 and 27.1 mgkg- 1. No significant differences were observed as regards pH (8.0 in both plots or the C/N ratio (7.7 and 7.1, respectively. Despite the short trial period of only three years, these results suggest that the agronomic model based on organic agriculture has a beneficial effect on soil properties and contributes to the function of soil as C sink.

  1. Internal Charging

    Science.gov (United States)

    Minow, Joseph I.

    2014-01-01

    (1) High energy (>100keV) electrons penetrate spacecraft walls and accumulate in dielectrics or isolated conductors; (2) Threat environment is energetic electrons with sufficient flux to charge circuit boards, cable insulation, and ungrounded metal faster than charge can dissipate; (3) Accumulating charge density generates electric fields in excess of material breakdown strenght resulting in electrostatic discharge; and (4) System impact is material damage, discharge currents inside of spacecraft Faraday cage on or near critical circuitry, and RF noise.

  2. Variabilidade espacial da fertilidade do solo em área cultivada e manejada homogeneamente Spatial soil fertility variability in a homogeneously managed corn field

    Directory of Open Access Journals (Sweden)

    Zaqueu Fernando Montezano

    2006-10-01

    ídios para a racionalização do uso de insumos.Insights on the variability of soil fertility in cultivated areas can contribute significantly to a rationalized use of fertilizers and soil amendments. The objective of this study was to determine the soil fertility variability through the fractionation of a commercial corn field into small management cells. The study was carried out on the farm Alto Alegre, Planaltina, GO, Brazil, on an Oxisol previously under Cerrado (savannah in an area of 373 ha under corn in the 2003/2004 growing season. A polygon was outlined and divided into 80 management cells of 4 ha each. The soil was sampled at twelve points along the plot diagonal to constitute a representative composite sample within each cell. The coordinates of these points were obtained and recorded. The soil samples were analyzed for texture and soil fertility. The yield for each cell was obtained with a harvester equipped with a Global Positioning System (GPS and grain yield monitor. Descriptive statistics parameters were considered in the analysis of data variability. It was carried out Pearson's simple linear correlation analysis at 5 and 1% significance level for soil fertility versus corn grain yield and altitude data. The variability was considered high for soil available phosphorus, copper and zinc concentrations; medium for soil organic matter, sulphur, calcium, and magnesium concentrations, potential acidity, sum of bases, CEC, base saturation, boron, iron as well as manganese concentration, but low for soil pH and potassium concentration. Linear correlation coefficients (LCC were significant and positive for soil organic matter and boron content versus corn yield. However, the LCC for copper, manganese and zinc content were significant and negative. Although it is normally not possible to isolate or measure all biotic and abiotic factors that affect the yield in field scale studies, knowledge on soil fertility variability and grain yield can contribute to a

  3. The effects of precipitation variability on C4 photosynthesis, net primary production and soil respiration in a Chihuahuan desert grassland

    Science.gov (United States)

    Michell L. Thomey

    2012-01-01

    Although the Earth's climate system has always been inherently variable, the magnitude and rate of anthropogenic climate change is subjecting ecosystems and the populations that they contain to novel environmental conditions. Because water is the most limiting resource, arid-semiarid ecosystems are likely to be highly responsive to future climate variability. The...

  4. Centimeter-scale spatial variability in 2-methyl-4-chlorophenoxyacetic acid mineralization increases with depth in agricultural soil

    DEFF Research Database (Denmark)

    Badawi, Nora; Johnsen, Anders R.; Sørensen, Jan

    2013-01-01

    Mineralization of organic chemicals in soil is typically studied using large homogenized samples, but little is known about the small-scale spatial distribution of mineralization potential. We studied centimeter-scale spatial distribution of 2-methyl-4-chlorophenoxyacetic acid (MCPA) mineralization...... activity at different depths (8-115 cm) in a Danish agricultural soil profi le using a 96-well microplate C-radiorespirometric method for small-volume samples. The heterotrophic microbial population and specifi c MCPA degraders decreased 10- to 100-fold from the plow layer to a depth of 115 cm. MCPA...... was mineralized in all samples in the plow layer, but only about 60% in the transition zone immediately below the plow layer showed mineralization; at greater depth even fewer samples showed mineralization. A patchy spatial distribution of mineralization activity was observed from right below the plow layer...

  5. Geochemical variability of heavy metals in soil after land use conversions in Northeast China and its environmental applications.

    Science.gov (United States)

    Jiao, Wei; Ouyang, Wei; Hao, Fanghua; Liu, Bing; Wang, Fangli

    2014-04-01

    The long-term agricultural reclamation since the 1950s has resulted in significant land use change from natural landscape to cultivated land in the Sanjiang Plain of Northeast China, which has had important consequences for many soil physical, chemical and biological processes. To understand the impact of land use conversions on heavy metal geochemistry, soil samples were collected from natural wetland, natural forestland, paddy land and dry farmland in a case study area and analyzed for total concentrations and chemical fractions of six heavy metals. Results showed that the natural wetland reclamation for the paddy land has caused obvious losses of Cd, Cu and Zn from the soils. In addition, a significant decrease in the Zn concentration was found after the land conversion from natural forestland to dry farmland. Because all the analyzed heavy metals predominated in the stable residual fraction regardless of the land use type, the response of metal mobility to the land use conversions was generally weak. Consequently, soil erosion was identified as the major factor that enhances heavy metal losses in the cultivated lands, especially in the paddy land. The close link between heavy metal loss and the reduction of clay and organic matter contents after land reclamation suggested that the diffuse heavy metal pollution occurred mainly in small erosion events. Considering the continuous paddy land expansion, special attention should be paid to the bioaccumulation of Pb in the paddy rice. Overall, these findings can help to improve the sustainability and safety of intensive agricultural activities in Northeast China as well as other similar areas.

  6. Landscape position influences soil respiration variability and sensitivity to physiological drivers in mixed-use lands of Southern California, USA

    Science.gov (United States)

    Crum, Steven M.; Liang, Liyin L.; Jenerette, G. Darrel

    2016-10-01

    Linking variation in ecosystem functioning to physiological and landscape drivers has become an important research need for understanding ecosystem responses to global changes. We investigate how these contrasting scale-dependent ecosystem drivers influence soil respiration (Rs), a key ecosystem process, using in situ landscape surveys and experimental subsidies of water and labile carbon. Surveys and experiments were conducted in summer and winter seasons and were distributed along a coastal to desert climate gradient and among the dominant land use classes in Southern California, USA. We found that Rs decreased from lawn to agricultural and wildland land uses for both seasons and along the climate gradient in the summer while increasing along the climate gradient in the winter. Rs variation was positively correlated with soil temperature and negatively to soil moisture and substrate. Water additions increased Rs in wildland land uses, while urban land uses responded little or negatively. However, most land uses exhibited carbon limitation, with wildlands experiencing largest responses to labile carbon additions. These findings show that intensively managed land uses have increased rates, decreased spatial variation, and decreased sensitivity to environmental conditions in Rs compared to wildlands, while increasing aridity has the opposite effect. In linking scales, physiological drivers were correlated with Rs but landscape position influenced Rs by altering both the physiological drivers and the sensitivity to the drivers. Systematic evaluation of physiological and landscape variation provides a framework for understanding the effects of interactive global change drivers to ecosystem metabolism across multiple scales.

  7. Cellulose and hemicellulose decomposition by forest soil bacteria proceeds by the action of structurally variable enzymatic systems

    Science.gov (United States)

    López-Mondéjar, Rubén; Zühlke, Daniela; Becher, Dörte; Riedel, Katharina; Baldrian, Petr

    2016-04-01

    Evidence shows that bacteria contribute actively to the decomposition of cellulose and hemicellulose in forest soil; however, their role in this process is still unclear. Here we performed the screening and identification of bacteria showing potential cellulolytic activity from litter and organic soil of a temperate oak forest. The genomes of three cellulolytic isolates previously described as abundant in this ecosystem were sequenced and their proteomes were characterized during the growth on plant biomass and on microcrystalline cellulose. Pedobacter and Mucilaginibacter showed complex enzymatic systems containing highly diverse carbohydrate-active enzymes for the degradation of cellulose and hemicellulose, which were functionally redundant for endoglucanases, β-glucosidases, endoxylanases, β-xylosidases, mannosidases and carbohydrate-binding modules. Luteibacter did not express any glycosyl hydrolases traditionally recognized as cellulases. Instead, cellulose decomposition was likely performed by an expressed GH23 family protein containing a cellulose-binding domain. Interestingly, the presence of plant lignocellulose as well as crystalline cellulose both trigger the production of a wide set of hydrolytic proteins including cellulases, hemicellulases and other glycosyl hydrolases. Our findings highlight the extensive and unexplored structural diversity of enzymatic systems in cellulolytic soil bacteria and indicate the roles of multiple abundant bacterial taxa in the decomposition of cellulose and other plant polysaccharides.

  8. Time-Lapse Geophysical Measurements targeting Spatial and Temporal Variability in Biogenic Gas Production from Peat Soils in a Hydrologically Controlled Wetland in the Florida Everglades

    Science.gov (United States)

    Wright, W. J.; Shahan, T.; Sharp, N.; Comas, X.

    2015-12-01

    Peat soils are known to release globally significant amounts of methane (CH4) and carbon dioxide (CO2) to the atmosphere. However, uncertainties still remain regarding the spatio-temporal distribution of gas accumulations and triggering mechanisms of gas releasing events. Furthermore, most research on peatland gas dynamics has traditionally been focused on high latitude peatlands. Therefore, understanding gas dynamics in low-latitude peatlands (e.g. the Florida Everglades) is key to global climate research. Recent studies in the Everglades have demonstrated that biogenic gas flux values may vary when considering different temporal and spatial scales of measurements. The work presented here targets spatial variability in gas production and release at the plot scale in an approximately 85 m2 area, and targets temporal variability with data collected during the spring months of two different years. This study is located in the Loxahatchee Impoundment Landscape Assessment (LILA), a hydrologically controlled, landscape scale (30 Ha) model of the Florida Everglades. Ground penetrating radar (GPR) has been used in the past to investigate biogenic gas dynamics in peat soils, and is used in this study to monitor changes of in situ gas storage. Each year, a grid of GPR profiles was collected to image changes in gas distribution in 2d on a weekly basis, and several flux chambers outfitted with time-lapse cameras captured high resolution (hourly) gas flux measurements inside the GPR grid. Combining these methods allows us to use a mass balance approach to estimate spatial variability in gas production rates, and capture temporal variability in gas flux rates.

  9. Influence of soil physical and chemical variables on species composition and richness of plants in the arid region of Tabuk, Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Al-Mutairi Khalid Awadh

    2017-06-01

    Full Text Available The present study aims to investigate the effect of soil physical and chemical variables on the species richness and the floristic composition in four sites (Alwaz, Alqan, Sharma and Zetah of Tabuk region in the Northwestern part of Arabian Peninsula. Only organic matter (OM, pH and calcium (Ca showed significant differences (P < 0.05 amongst the four studied sites. Only magnesium and sodium were selected in the forward regression model and showed to be strong drivers of species richness of plants in Tabuk region (Adj-R2 = 0.438, F2,13 = 6.85, P = 0.009. The multivariate analysis of canonical correspondence analysis (CCA was applied to reveal the effect of the physical and chemical variables on the species composition of the plants. The CCA classifies the plant species into three groups based on their preference to the environmental variables. The first group of plant species (Group 1 is characterised by positive preference to the chloride (Cl and negative relationship with OM and pH. The second group (Group 2 is positively correlated with most of the soil variables such as OM, calcium (Ca, potassium (K, bicarbonate (HCO3, electrical conductivity (EC, sulphate (SO4 and sodium (Na. The third group (Group 3 has positive relationship with carbonate (CO3 and negative relationship with EC and magnesium (Mg. The chloride, sodium, sulphate, EC and carbonate are the main environmental factors influencing the plant species composition in Tabuk region. The cluster analysis based on the Euclidian measure shows that Alqan and Zetah have closer species composition compared to Sharma.

  10. Major Changes in Growth Rate and Growth Variability of Beech (Fagus sylvatica L. Related to Soil Alteration and Climate Change in Belgium

    Directory of Open Access Journals (Sweden)

    Nicolas Latte

    2016-08-01

    Full Text Available Global change—particularly climate change, forest management, and atmospheric deposition—has significantly altered forest growing conditions in Europe. The influences of these changes on beech growth (Fagus sylvatica L. were investigated for the past 80 years in Belgium, using non-linear mixed effects models on ring-width chronologies of 149 mature and dominant beech trees (87–186 years old. The effects of the developmental stage (i.e., increasing tree size were filtered out in order to focus on time-dependent growth changes. Beech radial growth was divided into a low-frequency signal (=growth rate, mainly influenced by forest management and atmospheric deposition, and into a high-frequency variability (≈mean sensitivity, mainly influenced by climate change. Between 1930 and 2008, major long-term and time-dependent changes were highlighted. The beech growth rate has decreased by about 38% since the 1950–1960s, and growth variability has increased by about 45% since the 1970–1980s. Our results indicate that (1 before the 1980s, beech growth rate was not predominantly impacted by climate change but rather by soil alteration (i.e., soil compaction and/or nitrogen deposition; and (2 since the 1980s, climate change induced more frequent and intense yearly growth reductions that amplified the growth rate decrease. The highlighted changes were similar in the two ecoregions of Belgium, although more pronounced in the lowlands than in the uplands.

  11. Polychlorinated biphenyl concentrations, accumulation rates in soil from atmospheric deposition and analysis of their affecting landscape variables along an urban-rural gradient in Shanghai, China.

    Science.gov (United States)

    Fang, Shubo; Cui, Qu; Matherne, Brian; Hou, Aixin

    2017-11-01

    This study initiated an in-situ soil experimental system to quantify the annual dynamics of polychlorinated biphenyl (PCB) congener's concentrations and accumulation rates in soil from atmosphere deposition in a rural-urban fringe, and correlated them by landscape physical and demographic variables in the area. The results showed that the concentrations of all PCB congeners significantly increased with the sampling time (p urban center. The moderate average concentrations along the gradient for PCB 8, 18, and 28 were 31.003, 18.825, and 19.505 ng g-1, respectively. Tetra-CBs including PCB 44, 52, 66, and 77 were 10.243, 31.214, 8.330 and 9.530 ng g-1, respectively. Penta-CBs including PCB 101, 105, 118, and 126 were 9.465, 7.896, 17.703, and 6.363 ng g-1, respectively. Hexa-CBs including PCB 128, 138, 153, 170, 180, and 187 were 6.798, 11.522, 4.969, 6.722, 6.317, and 8.243 ng g-1 respectively. PCB 195, 206, and 209 were 8.259, 9.506, and 14.169 ng g-1, respectively. Most of the PCB congeners had a higher accumulation rate approximately 28 km from the urban center. The computed variables were found to affect the soil PCB concentrations with a threshold effect (p urban sprawling (i.e. built-up areas expanding) were the sources of PCBs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Spatial variability of microbial richness and diversity and relationships with soil organic carbon, texture and structure across an agricultural field

    DEFF Research Database (Denmark)

    Naveed, Muhammad; Herath, Lasantha; Møldrup, Per

    2016-01-01

    in triplicate, were used for measuring the soil water characteristic curve. Across the field, bacterial richness (number of OTUs) and diversity indices (Shannon diversity and phylogenetic diversity) showed strong spatial autocorrelations. Fungal number of OTUs was quite similar over the field and thus...... no spatial autocorrelation was observed for them. Fungal Shannon diversity slightly increased from south to north, with spatial autocorrelation for distances larger than 100 m. The ratio of clay to organic carbon (n) was found to be the best predictor of bacterial richness and diversity indices. Neither...

  13. Variabilidade espacial da salinidade de um solo aluvial no semi-árido Paraibano Spatial variability of soil salinity in an alluvial soil of the semi-arid region of Paraíba state

    Directory of Open Access Journals (Sweden)

    Lázaro Costa de Souza

    2000-04-01

    Full Text Available O objetivo deste trabalho foi estudar a variabilidade espacial do pH da pasta de saturação (pHps, condutividade elétrica do extrato de saturação (CEes e porcentagem de sódio trocável (PST de um solo aluvial afetado por sais. Foram coletadas amostras de solo nas camadas 0-20, 20-40 e 40-60 cm, numa área do Projeto de Irrigação Capoeira, localizado em São José do Bonfim, Estado da Paraíba, utilizando-se um esquema sistemático de amostragem numa malha regular de 10 x 15 m. Os dados foram analisados através da estatística descritiva e geoestatística. Verificou-se baixa variabilidade para o pHps (CV 60 %. Modelos esférico e gaussiano foram ajustados aos semivariogramas das variáveis que apresentaram estrutura de dependência espacial, tendo-se obtido alcances variando de 20 a 40 m. Os mapas de isolinhas da combinação da CEes e PST permitiram visualizar o padrão de variabilidade da salinidade e sodicidade, constituindo-se em uma ferramenta para a definição de estratégias de manejo edáfico e recuperação da área afetada.The objective of this work was to study the spatial variability of pH of saturation paste (pHsp, the electri