ORIGINAL RESEARCH:

G. B. Davis, J. L. Rayner, M. G. Trefry, S. J. Fisher, and B. M. Patterson

Measurement and Modeling of Temporal Variations in Hydrocarbon Vapor Behavior in a Layered Soil Profile
Risks posed by vapors are uncertain. Soil profile layering and moisture changes measured at a field site over a year are shown to dramatically alter the movement of hydrocarbon vapors towards the ground surface, and to alter estimates of vapor biodegradation rates. Wherever oxygen was found to be present, hydrocarbon vapors apparently biodegraded.
Published online 26 April 2005; doi:10.2136/vzj2004.0029
Vadose Zone J 2005 4: 225-239. [Abstract] [Full Text] [Figures Only] [PDF]  

M. Herbst, W. Fialkiewicz, T. Chen, T. Pütz, D. Thiéry, C. Mouvet, G. Vachaud, and H. Vereecken

Intercomparison of Flow and Transport Models Applied to Vertical Drainage in Cropped Lysimeters
Free draining lysimeters were used to measure drainage, soil moisture, evapotranspiration, soil temperature, and transport of the pesticide methabenzthiazuron. An application of MACRO, MARTHE, TRACE, and ANSWERS to the lysimeter data reveals the conceptual strengths and weaknesses of the different model approaches.
Published online 26 April 2005; doi:10.2136/vzj2004.0070
Vadose Zone J 2005 4: 240-254. [Abstract] [Full Text] [Figures Only] [PDF]  

Alex Furman and A. W. Warrick

Unsaturated Flow Through Spherical Inclusions with Contrasting Sorptive Numbers
An analytic element method for a spherical inclusion of contrasting hydraulic properties in a uniform vertical flow field is presented. The solution requires the numerical matching of both pressure head and normal flux at sphere interface and is iterative due to nonlinearity in the head boundary condition. With contrasting sorptive numbers, reversal of inclusion properties may occur for different background fluxes.
Published online 26 April 2005; doi:10.2136/vzj2004.0076
Vadose Zone J 2005 4: 255-263. [Abstract] [Full Text] [Figures Only] [PDF]  

Bhabani S. Das, Nathan W. Haws, and P. Suresh C. Rao

Defining Geometric Similarity in Soils
Scaling techniques implicitly assume geometric similitude for the soils being scaled; however, the meaning of similar media is not clear. This study shows that similar media can be classified based on the coefficient of variation of standard deviations of soil pore size distributions. A coefficient of variation <10% may be used as a cutoff for similar soils.
Published online 26 April 2005; doi:10.2136/vzj2004.0113
Vadose Zone J 2005 4: 264-270. [Abstract] [Full Text] [Figures Only] [PDF]  

Annette E. Rosenbom and Peter R. Jakobsen

Infrared Thermography and Fracture Analysis of Preferential Flow in Chalk
At a Cretaceous chalk site a range of fracture characterization properties were measured, including origin, orientation, trace length, spacing, coating, connectivity, and hydraulic activity. This information was combined with infrared thermography measurements to determine the main hydraulically active conduits at the site.
Published online 26 April 2005; doi:10.2136/vzj2004.0074
Vadose Zone J 2005 4: 271-280. [Abstract] [Full Text] [Figures Only] [PDF]  

H.-J. Vogel, J. Tölke, V. P. Schulz, M. Krafczyk, and K. Roth

Comparison of a Lattice-Boltzmann Model, a Full-Morphology Model, and a Pore Network Model for Determining Capillary Pressure–Saturation Relationships
The soil water retention characteristic is predicted based on the microscopic structure of the pore space. Three different models having different complexity are compared: a Lattice-Boltzmann simulation, a pure geometric approach, and a network model.
Published online 13 May 2005; doi:10.2136/vzj2004.0114
Vadose Zone J 2005 4: 380-388. [Abstract] [Full Text] [Figures Only] [PDF]  

E. Unsal, J. H. Dane, and G. V. Dozier

A Genetic Algorithm for Predicting Pore Geometry Based on Air Permeability Measurements
A genetic optimization algorithm and a probability distribution function were applied to air permeability vs. volumetric water data derived from a sandstone core sample to estimate the pore size distribution and pore configuration of the sandstone. The derived pore information was used to predict the water retention curve for the sandstone.
Published online 13 May 2005; doi:10.2136/vzj2004.0116
Vadose Zone J 2005 4: 389-397. [Abstract] [Full Text] [Figures Only] [PDF]  

Mats Larsbo, Stephanie Roulier, Fredrik Stenemo, Roy Kasteel, and Nicholas Jarvis

An Improved Dual-Permeability Model of Water Flow and Solute Transport in the Vadose Zone
Measured data from a high time-resolution tracer microlysimeter experiment were accurately reproduced by simulations using an improved version of MACRO. Parameter identification with the GLUE procedure adequately constrained the mass exchange coefficient, indicating that it would be identifiable in inverse procedures.
Published online 13 May 2005; doi:10.2136/vzj2004.0137
Vadose Zone J 2005 4: 398-406. [Abstract] [Full Text] [Figures Only] [PDF]  

M. L. Rockhold, R. R. Yarwood, M. R. Niemet, P. J. Bottomley, and J. S. Selker

Experimental Observations and Numerical Modeling of Coupled Microbial and Transport Processes in Variably Saturated Sand
The impact of the growth of Pseudomonas fluorescens on the hydraulic properties of variably saturated porous media was studied using packed laboratory columns. A numerical model of coupled fluid flow and multicomponent mass transport was used to simulate measured moisture content, water pressure, biomass concentrations, and effluent fluxes.
Published online 13 May 2005; doi:10.2136/vzj2004.0087
Vadose Zone J 2005 4: 407-417. [Abstract] [Full Text] [Figures Only] [PDF]  

Joseph A. Kozak, Lajpat R. Ahuja, Liwang Ma, and Tim R. Green

Scaling and Estimation of Evaporation and Transpiration of Water across Soil Textures
Relationships between simulated evaporation and transpiration and the pore-size distribution index across dissimilar soil textures were used to estimate evaporation and transpiration for a range of potential rates in initially wet soils. The results were found useful in quantifying spatial variability of evaporation and transpiration in the field.
Published online 13 May 2005; doi:10.2136/vzj2004.0119
Vadose Zone J 2005 4: 418-427. [Abstract] [Full Text] [Figures Only] [PDF]  

J. S. Tyner, W. C. Wright, J. Lee, and A. D. Crenshaw

A Dynamic Air Permeameter for Coarse-Textured Soil Columns and Cores
A new method is presented for measuring the air permeability of soil columns and cores. Dry air is pumped through an initially wet soil sample, which completely dries coarse-textured samples within 1 to 2 d. Concurrently, water content and air pressure measurements are collected to enable calculation of air permeability.
Published online 13 May 2005; doi:10.2136/vzj2004.0092
Vadose Zone J 2005 4: 428-433. [Abstract] [Full Text] [Figures Only] [PDF]  

T. N. Narasimhan

Buckingham, 1907: An Appreciation
Buckingham's methodical development of an unsaturated flow theory from first principles facilitates a grasp that one seldom gets from textbooks. While providing a dynamical basis for studying soil moisture, Buckingham understood the problem well enough to be skeptical about its mathematical tractability. Soil physics education is incomplete without a reading of Buckingham's enjoyable masterpiece.
Published online 13 May 2005; doi:10.2136/vzj2004.0126
Vadose Zone J 2005 4: 434-441. [Abstract] [Full Text] [Figures Only] [PDF]  

SPECIAL SECTION: ZNS'03 VADOSE ZONE RESEARCH:

Javier Álvarez-Benedí

Preface: ZNS'03 Vadose Zone Research
The guest editor introduces the special section derived from the "Zona No Saturada" 2003 conference in Valladolid, Spain. The studies reported in these articles demonstrate the global growth of vadose zone research.
Published online 13 May 2005; doi:10.2136/vzj2005.0037
Vadose Zone J 2005 4: 281. [Full Text] [PDF]  

J. Álvarez-Benedí, S. Bolado, I. Cancillo, C. Calvo, and D. García-Sinovas

Adsorption–Desorption of Arsenate in Three Spanish Soils
The kinetics and the equilibria of adsorption and desorption of Arsenate in three Spanish soils are studied. The authors evaluate the effects of temperature and the presence of other ions (phosphate, nitrate, chloride, and sulfate) on the adsorption isotherm of arsenate in soils.
Published online 13 May 2005; doi:10.2136/vzj2004.0095
Vadose Zone J 2005 4: 282-290. [Abstract] [Full Text] [Figures Only] [PDF]  

C. M. Regalado, A. Ritter, J. Álvarez-Benedí, and R. Muñoz-Carpena

Simplified Method to Estimate the Green–Ampt Wetting Front Suction and Soil Sorptivity with the Philip–Dunne Falling-Head Permeameter
A simple method is presented to estimate the soil saturated hydraulic conductivity and the Green-Ampt wetting front suction with the Philip-Dunne falling-head permeameter. Only the times when the permeameter is half full and empty are necessary for the proposed new method, but not the soil moisture increment required by earlier methods.
Published online 13 May 2005; doi:10.2136/vzj2004.0103
Vadose Zone J 2005 4: 291-299. [Abstract] [Full Text] [Figures Only] [PDF]  

A. Ritter, R. Muñoz-Carpena, C. M. Regalado, M. Javaux, and M. Vanclooster

Using TDR and Inverse Modeling to Characterize Solute Transport in a Layered Agricultural Volcanic Soil
Peculiarities of volcanic soils may influence the movement of solutes through the vadose zone. Bromide transport in a volcanic soil was analyzed by TDR and inverse modeling. Characterization of bromide transport highlighted a delay in bromide breakthrough, which relates to the high Fe and Al oxihydroxides contents typical of these soils.
Published online 13 May 2005; doi:10.2136/vzj2004.0094
Vadose Zone J 2005 4: 300-309. [Abstract] [Full Text] [Figures Only] [PDF]  

Francisco J. Jiménez-Hornero, Juan V. Giráldez, and Ana Laguna

Simulation of Tracer Dispersion in Porous Media Using Lattice Boltzmann and Random Walk Models
The lattice Boltzmann and Random Walk models are presented for describing pore-scale transport processes. Results show that both approaches are valid alternatives to conventional models.
Published online 13 May 2005; doi:10.2136/vzj2004.0090
Vadose Zone J 2005 4: 310-316. [Abstract] [Full Text] [Figures Only] [PDF]  

Karl Vanderlinden, Juan V. Giráldez, and Marc Van Meirvenne

Soil Water-Holding Capacity Assessment in Terms of the Average Annual Water Balance in Southern Spain
Spatial estimation of the soil water-holding capacity at the regional scale from scarce soil data requires the use of pedotransfer functions and geostatistics. A regional assessment of the average annual water balance in southern Spain suggests that available pedotransfer functions underestimate regional soil water-holding capacity.
Published online 13 May 2005; doi:10.2136/vzj2004.0099
Vadose Zone J 2005 4: 317-328. [Abstract] [Full Text] [Figures Only] [PDF]  

S. Bolado Rodríguez, A. Alonso-Gaite, and J. Álvarez-Benedí

Characterization of Nitrogen Transformations, Sorption and Volatilization Processes In Urea Fertilized Soils
Nitrogen transformations in soils following urea application were monitored in controlled laboratory batch experiments. Rate data for N transformations and coupled sorption processes were determined from the experimental data and are presented as a function of temperature, soil moisture content, and initial concentration of applied urea.
Published online 13 May 2005; doi:10.2136/vzj2004.0102
Vadose Zone J 2005 4: 329-336. [Abstract] [Full Text] [Figures Only] [PDF]  

Daniel Ronen, Ellen R. Graber, and Yael Laor

Volatile Organic Compounds in the Saturated–Unsaturated Interface Region of a Contaminated Phreatic Aquifer
Temporal analysis of profiles of volatile organic compounds within the saturated-unsaturated interface region of a contaminated phreatic aquifer is presented. The profiles were obtained with a passive multilayer sampler that allows detection of differences as great as 24000 micrograms TCE per liter of air between samples located at a vertical interval of only 12 cm.
Published online 13 May 2005; doi:10.2136/vzj2004.0100
Vadose Zone J 2005 4: 337-344. [Abstract] [Full Text] [Figures Only] [PDF]  

Roberto Rodríguez, Lucila Candela, and Antonio Lloret

Experimental System for Studying the Hydromechanical Behavior of Porous Media
An automated laboratory apparatus used to study the hydraulic properties of variably saturated porous media is described. Accurate temporal measures of temperature, water content, and soil suction inside the sample can be made. A unique feature of the apparatus is that it is capable of quantifying behavior for media undergoing shrinkage or swelling.
Published online 13 May 2005; doi:10.2136/vzj2004.0105
Vadose Zone J 2005 4: 345-353. [Abstract] [Full Text] [Figures Only] [PDF]  

REVIEWS AND ANALYSES:

Wa'il Y. Abu-El-Sha'r and Jehad Y. Al-Zou'by

Significance of Well Locations and Flow Rates in Bioventing Systems Design
The optimal well locations and flow rates to maximize mass removal of subsurface contaminants using bioventing systems, subject to certain physical and budgetary constraints, were explored. Wells placed on the centerline of the contaminant plume achieved best results. Findings were applied to a field case study.
Published online 13 May 2005; doi:10.2136/vzj2004.0055
Vadose Zone J 2005 4: 354-359. [Abstract] [Full Text] [Figures Only] [PDF]  

Frédérick Delay, Philippe Ackerer, and Charles Danquigny

Simulating Solute Transport in Porous or Fractured Formations Using Random Walk Particle Tracking: A Review
Random walk may be an efficient numerical method to simulate solute transport in saturated or unsaturated porous material. Topics covered in this review include theoretical aspects of the methods, various numerical implementations including reactive transport, and continuous time and time domain random walk.
Published online 13 May 2005; doi:10.2136/vzj2004.0125
Vadose Zone J 2005 4: 360-379. [Abstract] [Full Text] [PDF]  

BOOK REVIEWS:

Warren Busscher

Soil Tillage in Agroecosystems.
Published online 13 May 2005; doi:10.2136/vzj2003.0016br
Vadose Zone J 2005 4: 442. [Full Text] [PDF]  

Thomas Harter

Groundwater Recharge in a Desert Environment: The Southwestern United States.
Published online 13 May 2005; doi:10.2136/vzj2004.0001br
Vadose Zone J 2005 4: 443-444. [Full Text] [PDF]  

George F. Vance

Soil and Water Chemistry: An Integrated Approach.
Published online 13 May 2005; doi:10.2136/vzj2004.0002br
Vadose Zone J 2005 4: 445. [Full Text] [PDF]  

D. Wang

Agrometeorology: Principles and Applications of Climate Studies in Agriculture.
Published online 13 May 2005; doi:10.2136/vzj2004.0004br
Vadose Zone J 2005 4: 446. [Full Text] [PDF]  

Ruth H. Ellerbrock

Pesticide Residues: Significance, Management and Analysis.
Published online 13 May 2005; doi:10.2136/vzj2004.0007br
Vadose Zone J 2005 4: 447. [Full Text] [PDF]  

Maria Inés Dragila

Principles of Soil Physics.
Published online 13 May 2005; doi:10.2136/vzj2004.0012br
Vadose Zone J 2005 4: 448. [Full Text] [PDF]  

Laosheng Wu

An Introduction to the Environmental Physics of Soil, Water and Watersheds.
Published online 13 May 2005; doi:10.2136/vzj2004.0013br
Vadose Zone J 2005 4: 449. [Full Text] [PDF]  

Hector Causarano

Fundamentals of Soil Ecology.
Published online 13 May 2005; doi:10.2136/vzj2004.0014br
Vadose Zone J 2005 4: 450. [Full Text] [PDF]  

Markus Berli and Dani Or

Unsaturated Soil Mechanics.
Published online 13 May 2005; doi:10.2136/vzj2005.0002br
Vadose Zone J 2005 4: 451. [Full Text] [PDF]  

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