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Volume 6 Issue 1, February 2007



  • REVIEWS AND ANALYSES up

    • H. Vereecken, R. Kasteel, J. Vanderborght and T. Harter
      Upscaling Hydraulic Properties and Soil Water Flow Processes in Heterogeneous Soils
      EXECUTIVE SUMMARY Two approaches commonly used to upscale soil water processes and hydraulic properties, forward upscalingand inverse modeling, are reviewed. The topics reviewed include stochastic theories, the scaleway, the streamtubeapproach, aggregation, inverse modeling, and data fusion. Each approach is discussed, and recommendationsare presented.
      doi:10.2136/vzj2006.0055
      Vadose Zone Journal 2007 6:1-28
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    • Jan Vanderborght and Harry Vereecken
      Review of Dispersivities for Transport Modeling in Soils
      EXECUTIVE SUMMARY We review dispersivities derived from tracer experiments in soils and assess the effect of experimental conditions on dispersivity. This review may help practitioners who need ranges of realistic dispersivity values to model transport in soils and experimentalists designing relevant experiments.
      doi:10.2136/vzj2006.0096
      Vadose Zone Journal 2007 6:29-52
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  • ORIGINAL RESEARCH up

    • Nan Hong, Jeffrey G. White, Randy Weisz, Marcia L. Gumpertz, Miressa G. Duffera and D. Keith Cassel
      Groundwater Nitrate Spatial and Temporal Patterns and Correlations
      EXECUTIVE SUMMARY We examined the spatial and temporal dynamics of shallow groundwater nitrate-nitrogen under a 2-yr crop rotation in the southeastern Coastal Plain. In-season, site-specific, variable-rate N management disrupted the intrinsic spatial and temporal patterns of groundwater nitrate-nitrogen, which instead reflected the spatial and temporal variability in N applications.
      doi:10.2136/vzj2006.0065
      Vadose Zone Journal 2007 6:53-66
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    • Tyler K. Birkham, M. Jim Hendry, Leonard I. Wassenaar and Carl A. Mendoza
      A Transient Model of Vadose Zone Reaction Rates Using Oxygen Isotopes and Carbon Dioxide
      EXECUTIVE SUMMARY Microbial respiration rates via the alternative oxidase pathway were characterized by modeling profiles of vadose zone oxygen isotope and carbon dioxide concentrations over a 990-day period. The utility of complimentary and transient oxygen and carbon dioxide modeling was emphasized.
      doi:10.2136/vzj2006.0005
      Vadose Zone Journal 2007 6:67-76
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    • Boris Faybishenko
      Climatic Forecasting of Net Infiltration at Yucca Mountain Using Analogue Meteorological Data
      EXECUTIVE SUMMARY A precipitation-temperature-based approach is used for calculations of net infiltration, aridity, and precipitation-effectiveness indices, using a modified Budyko's water-balance model, with potential evapotranspiration determined from the temperature-based Thornthwaite formula.
      doi:10.2136/vzj2006.0001
      Vadose Zone Journal 2007 6:77-92
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    • Radek Fučík, Jiří Mikyška, Michal Beneš and Tissa H. Illangasekare
      An Improved Semi-Analytical Solution for Verification of Numerical Models of Two-Phase Flow in Porous Media
      EXECUTIVE SUMMARY Our aim is to provide a detailed analysis of how the solution to the governing equation of two-phase flow can be obtained from a functional integral equation given by the analytical treatment of the problem and present an improved algorithm for the implementation of this solution.
      doi:10.2136/vzj2006.0024
      Vadose Zone Journal 2007 6:93-104
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    • Till Sander and Horst H. Gerke
      Preferential Flow Patterns in Paddy Fields Using a Dye Tracer
      EXECUTIVE SUMMARY Ponded infiltration of a Brilliant Blue solution in paddy soils in southeast China revealed preferred flow paths extending into the unsaturated subsoil. Stained areas indicated a redistribution zone on top of the compacted layer and a transition from more crack-type pathways in the plow pan to more cylindrical-type pathways in the subsoil.
      doi:10.2136/vzj2006.0035
      Vadose Zone Journal 2007 6:105-115
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    • N. Lazarovitch, A. W. Warrick, A. Furman and J. Šimůnek
      Subsurface Water Distribution from Drip Irrigation Described by Moment Analyses
      EXECUTIVE SUMMARY Spatial moments describing subsurface water distribution from drip sources are presented for numerically generated data. These analyses allow a straightforward, physically meaningful description of the general pattern of water distribution around surface and subsurface sources.
      doi:10.2136/vzj2006.0052
      Vadose Zone Journal 2007 6:116-123
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    • Klaas Metselaar and Quirijn de Jong van Lier
      The Shape of the Transpiration Reduction Function under Plant Water Stress
      EXECUTIVE SUMMARY The linear reduction of crop transpiration with decreasing soil water content is shown to hold theoretically for soils with a constant diffusivity. More generally, transpiration reduction is a concave function of soil water content.
      doi:10.2136/vzj2006.0086
      Vadose Zone Journal 2007 6:124-139
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    • Jan Vanderborght and Harry Vereecken
      One-Dimensional Modeling of Transport in Soils with Depth-Dependent Dispersion, Sorption and Decay
      EXECUTIVE SUMMARY We predicted leaching of reactive substances by three transport models that make different assumptions about the dispersion process. Although the models predicted the same inert tracer breakthrough at 1-m depth, they predicted different breakthrough curves of reactive substances in soil profiles with decreasing sorption and decay rate with depth.
      doi:10.2136/vzj2006.0103
      Vadose Zone Journal 2007 6:140-148
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    • Lirong Zhong, Edward C. Thornton and Baolin Deng
      Uranium Immobilization by Hydrogen Sulfide Gaseous Treatment under Vadose Zone Conditions
      EXECUTIVE SUMMARY Uranium immobilization in vadose zone by sediments treated with diluted hydrogen sulfide in nitrogen gaseous mixture is evaluated. Soil treated with moisturized hydrogen sulfide gas can immobilize >80% of mobile uranium in the first 20 pore volumes by U(VI) adsorption and reduction of U(VI) to insoluble U(IV).
      doi:10.2136/vzj2006.0114
      Vadose Zone Journal 2007 6:149-157
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    • James B. Callegary, Ty P. A. Ferré and R. W. Groom
      Vertical Spatial Sensitivity and Exploration Depth of Low-Induction-Number Electromagnetic-Induction Instruments
      EXECUTIVE SUMMARY Low-induction-number instruments are used to map a variety of soil properties: salinity, texture, moisture content, contaminant distribution. Simulation results indicate that even at typical values soil electrical conductivity significantly affects instrument spatial sensitivity and exploration depth though these are often assumed to be fixed.
      doi:10.2136/vzj2006.0120
      Vadose Zone Journal 2007 6:158-167
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    • Anvar Kacimov
      Dipole-Generated Unsaturated Flow in Gardner Soils
      EXECUTIVE SUMMARY Vertical infiltration in a Gardner soil containing an obstacle is studied using Bystrov's solution to the advection-dispersion equation. The solution derived by superposition of dipole and uniform flow terms is expressed in terms of stream and potential functions. An explicit expression for the stream function is a unique feature of this solution.
      doi:10.2136/vzj2005.0141
      Vadose Zone Journal 2007 6:168-174
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    • M. Mostafa and P. J. Van Geel
      Conceptual Models and Simulations for Biological Clogging in Unsaturated Soils
      EXECUTIVE SUMMARY Different conceptual models are proposed that relate the relative permeability term for unsaturated flow to the volume of biomass present due to biodegradation. Numerical simulations are presented to illustrate how the models predict clogging for continuous and pulsed loading scenarios.
      doi:10.2136/vzj2006.0033
      Vadose Zone Journal 2007 6:175-185
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    • Jianting Zhu, Michael H. Young and Martinus Th. van Genuchten
      Upscaling Schemes and Relationships for the Gardner and van Genuchten Hydraulic Functions for Heterogeneous Soils
      EXECUTIVE SUMMARY Upscaled averaging schemes of heterogeneous soil hydraulic properties are needed for many large-scale hydrologic applications, like regional and global climate studies. The schemes are based on two new criteria that preserve the ensemble vertical moisture flux across the land-atmosphere boundary and the ensemble moisture content at the soil surface.
      doi:10.2136/vzj2006.0041
      Vadose Zone Journal 2007 6:186-195
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    • Gerben Bakker, Martine J. van der Ploeg, Gerrit H. de Rooij, Cornelis W. Hoogendam, Hermanus P. A. Gooren, Cindy Huiskes, Luuk K. Koopal and Henk Kruidhof
      New Polymer Tensiometers: Measuring Matric Pressures Down to the Wilting Point
      EXECUTIVE SUMMARY Soil physical experimental research is hampered by the very limited measurement range of water-filled tensiometers. A newly developed polymer tensiometer measures matric pressures down to the wilting point, keeps working for at least several months, and is able to regain pressure without user interference.
      doi:10.2136/vzj2006.0110
      Vadose Zone Journal 2007 6:196-202
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  • ERRATUM up

    • N. Lazarovitch, A. W. Warrick, A. Furman and J. Šimůnek
      Subsurface Water Distribution from Drip Irrigation Described by Moment Analyses
      doi:10.2136/vzj2006.0052er
      Vadose Zone Journal 2007 6:203-203
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  • THANKS TO OUR REVIEWERS up


    • Thanks to Our Reviewers
      doi:10.2136/vzj2006.0001ThRv
      Vadose Zone Journal 2007 6:204-206
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