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You searched for: Journal name Vadose zone journal Remove constraint Journal name: Vadose zone journal Publication year rev 7994-2006 Remove constraint Publication year rev: 7994-2006 Publication Year 2006 Remove constraint Publication Year: 2006 Subject term soil pore system Remove constraint Subject term: soil pore system
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1. Applicability of Uni- and Bimodal Retention Functions for Water Flow Modeling in a Tropical Acrisol

Author:
Klaus Spohrer; Ludger Herrmann; Joachim Ingwersen; Karl Stahr
Source:
Vadose zone journal 2006 v.5 no.1 pp. 48-58
ISSN:
1539-1663
Subject:
simulation models; soil pore system; tropical soils; unsaturated hydraulic conductivity; soil water characteristic; soil water movement; Thailand
Abstract:
... Modeling soil water fluxes is an important part of many agricultural and environmental investigations and applications. A prerequisite for accurate modeling results is a sound parameterization of the soil hydraulic functions. The aim of this study was to investigate whether the unimodal retention function is sufficient to simulate the soil water regime of an Acrisol in Northern Thailand. The van G ...
DOI:
10.2136/vzj2005.0047

2. Bimodal Probability Law Model for Unified Description of Water Retention, Air and Water Permeability, and Gas Diffusivity in Variably Saturated Soil

Author:
Tjalfe G. Poulsen; Per Moldrup; Seiko Yoshikawa; Toshiko Komatsu
Source:
Vadose zone journal 2006 v.5 no.4 pp. 1119-1128
ISSN:
1539-1663
Subject:
soil heterogeneity; volcanic ash soils; Andisols; soil vapor extraction; mathematical models; soil pore system; permeability; air; water; soil water retention; soil transport processes; saturated hydraulic conductivity; unsaturated hydraulic conductivity; vadose zone; diffusivity
Abstract:
... Air and water permeabilities and gas diffusivity as functions of soil fluid phase (air or water) contents are governing chemical transport and fate processes in the vadose zone, and have frequently been identified as the three main transport parameters determining time and efficiency during soil vapor extraction (soil venting) at polluted soil sites. A mathematically flexible function that can acc ...
DOI:
10.2136/vzj2005.0146

3. Characterizing Pore-Scale Configuration of Organic Immiscible Liquid in Multiphase Systems With Synchrotron X-Ray Microtomography

Author:
G. Schnaar; M. L. Brusseau
Source:
Vadose zone journal 2006 v.5 no.2 pp. 641-648
ISSN:
1539-1663
Subject:
porous media; sandy soils; sand; tetrachloroethylene; soil pore system; tomography; X-radiation; spatial distribution; soil water; soil pollution
Abstract:
... The objective of this study was to examine the pore-scale distribution and morphology of organic immiscible liquid in natural porous media containing three immiscible fluids. High-resolution, three-dimensional images of an organic liquid (tetrachloroethene) in both three-phase (water–air–organic liquid) and two-phase (water–organic liquid) systems were obtained using synchrotron X-ray microtomogra ...
DOI:
10.2136/vzj2005.0063

4. Colloid Mobilization from a Variably Saturated, Intact Soil Core

Author:
Janna M. Levin; Janet S. Herman; George M. Hornberger; James E. Saiers
Source:
Vadose zone journal 2006 v.5 no.2 pp. 564-569
ISSN:
1539-1663
Subject:
soil colloids; soil transport processes; unsaturated conditions; unsaturated flow; soil pore system; diffusion; infiltration (hydrology)
Abstract:
... Colloids may transport contaminants through unsaturated soils to the groundwater, and colloid mobilization is associated with transient hydrological events and sustained, steady flow. We examined mechanisms of colloid mobilization from an intact, unsaturated soil core during relatively steady flow. We collected the core from a site where soils contain 26% clay and infiltration occurs only at capil ...
DOI:
10.2136/vzj2005.0102

5. Dependence of the Electrical Conductivity on Saturation in Real Porous Media

Author:
R. P. Ewing; A. G. Hunt
Source:
Vadose zone journal 2006 v.5 no.2 pp. 731-741
ISSN:
1539-1663
Subject:
porous media; infiltration (hydrology); electrical conductivity; porosity; soil pore system; soil salinity; saturated conditions
Abstract:
... Archie's Law for the porosity and saturation dependence of electrical conductivity, σ(θ) = aσbϕᵐ(θ/ϕ)ⁿ (where σ is electrical conductivity, the subscript b denotes the brine or bulk solution, ϕ is porosity, θ is volume wetness, and a, m, and n are fitting parameters) was recently derived by applying continuum percolation theory to fractal porous media. We have recast Archie's Law in terms of satur ...
DOI:
10.2136/vzj2005.0107

6. Effects of Soil Porosity on Slope Stability and Debris Flow Runout at a Weathered Granitic Hillslope

Author:
Muhammad Mukhlisin; Ken'ichirou Kosugi; Yoshifumi Satofuka; Takahisa Mizuyama
Source:
Vadose zone journal 2006 v.5 no.1 pp. 283-295
ISSN:
1539-1663
Subject:
landslides; mathematical models; soil pore system; saturated conditions; soil water content; porosity; granite; infiltration (hydrology); rain; hills
Abstract:
... Accurate models of rainfall infiltration are needed for analysis and prediction of slope failure induced by heavy rainfall. In this study, a numerical model was developed to simulate two-dimensional rainwater infiltration into an unsaturated hillslope, the formation of a saturated zone, and the resultant changes in slope stability. This model was subsequently used to analyze the effects of soil po ...
DOI:
10.2136/vzj2005.0044

7. Equivalent Soil Pore Geometry to Determine Effective Water Permeability

Author:
E. Unsal; J. H. Dane
Source:
Vadose zone journal 2006 v.5 no.4 pp. 1278-1280
ISSN:
1539-1663
Subject:
soil pore system; permeability; water; soil water content; mathematics and statistics
Abstract:
... Knowledge of hydraulic properties is essential for predicting flow and transport in porous media. Previously, Unsal et al. presented a procedure to determine an equivalent pore size distribution and pore geometry of a sandstone core using effective air permeability values as a function of volumetric water content in conjunction with a genetic algorithm for optimization purposes. They also showed h ...
DOI:
10.2136/vzj2006.0034

8. Field Testing of a Soil Corer Air Permeameter (SCAP) in Desert Soils

Author:
Karletta Chief; Ty P. A. Ferré; Bart Nijssen
Source:
Vadose zone journal 2006 v.5 no.4 pp. 1257-1263
ISSN:
1539-1663
Subject:
saturated hydraulic conductivity; agricultural soils; gases; mathematical models; soil pore system; permeameters; flow; desert soils; measurement; permeability; Arizona
Abstract:
... Measurements of air permeability are useful both directly, to assess gas phase movement through soils, and indirectly as a proxy for soil hydraulic conductivity. Several designs have been presented for field-based air permeameters; however, none are suitable for use in gravelly desert soils. We designed an air permeameter compatible with a standard soil corer to facilitate insertion into desert so ...
DOI:
10.2136/vzj2006.0063

9. Gas Transport Parameters in the Vadose Zone: Development and Tests of Power-Law Models for Air Permeability

Author:
Ken Kawamoto; Per Moldrup; Per Schjønning; Bo V. Iversen; Toshiko Komatsu; Dennis E. Rolston
Source:
Vadose zone journal 2006 v.5 no.4 pp. 1205-1215
ISSN:
1539-1663
Subject:
soil profiles; mathematical models; soil pore system; unsaturated hydraulic conductivity; diffusivity; porosity; soil air; air; soil transport processes; vadose zone; permeability
Abstract:
... The soil-air permeability (k ₐ) and its dependency on air-filled porosity (ε) govern convective air and gas transport in soil. For example, accurate prediction of k ₐ(ε) is a prerequisite for optimizing soil vapor extraction systems for cleanup of soils polluted with volatile organic chemicals. In this study, we measured k ₐ at different soil-water matric potentials down to 5.6-m depth, totaling 2 ...
DOI:
10.2136/vzj2006.0030

10. Gas Transport Parameters in the Vadose Zone: Gas Diffusivity in Field and Lysimeter Soil Profiles

Author:
Kawamoto, K.; Moldrup, P.; Schjonning, P.; Iversen, B.V.; Rolston, D.E.; Komatsu, T.
Source:
Vadose zone journal 2006 v.5 no.4 pp. 1194-1204
ISSN:
1539-1663
Subject:
vadose zone; diffusivity; soil profiles; lysimeters; gases; flow; soil air; soil transport processes; soil texture; mathematical models; soil pore system; permeability
Abstract:
... The main soil-gas transport parameters, gas diffusivity and air permeability, and their variations with soil type and air-filled porosity play a key role in soil-gas emission problems including volatilization of toxic chemicals at polluted sites and the production and emission of greenhouse gases. Only limited information on soil-gas transport parameters across the vadose zone is available, especi ...
DOI:
10.2136/vzj2006.0014

11. Modeling the Relationship between Soil Bulk Density and the Water Retention Curve

Author:
S. Assouline
Source:
Vadose zone journal 2006 v.5 no.2 pp. 554-563
ISSN:
1539-1663
Subject:
soil water characteristic; soil density; bulk density; soil water retention; mathematical models; soil pore system
Abstract:
... Increases in the soil bulk density during compaction may influence many aspects of the soil–water–plant–atmosphere system. An empirical approach is suggested that could model the effect of an increase in soil bulk density on the water retention curve (WRC). Two expressions of the WRC are considered. Relationships between their parameters and the bulk density of a compacted soil were calibrated and ...
DOI:
10.2136/vzj2005.0083

12. Nitrous Oxide and Ammonia Emissions from Urine-Treated Soils

Author:
Olga Singurindy; Brian K. Richards; Marina Molodovskaya; Tammo S. Steenhuis
Source:
Vadose zone journal 2006 v.5 no.4 pp. 1236-1245
ISSN:
1539-1663
Subject:
urine; soil treatment; gas emissions; nitrous oxide; ammonia; soil texture; sand; soil water content; soil depth; soil pore system; wind; denitrification; denitrifying microorganisms; evaporation; volatilization
Abstract:
... Urine-treated soils have been implicated as an important source of gaseous N losses to the atmosphere. The goal of our research was to quantify NH₃ and N₂O emissions from urine under different simplified and controlled soil conditions and to relate these results to urinary-N transformation processes in soil. We studied the influence of soil texture (coarse vs. fine sand), moisture distribution wit ...
DOI:
10.2136/vzj2006.0073

13. Numerical Analysis of Coupled Water, Vapor, and Heat Transport in the Vadose Zone

Author:
Hirotaka Saito; Jiri Šimůnek; Binayak P. Mohanty
Source:
Vadose zone journal 2006 v.5 no.2 pp. 784-800
ISSN:
1539-1663
Subject:
mathematical models; water vapor; soil pore system; soil water content; soil temperature; unsaturated conditions; soil air; soil thermal properties; energy balance; heat transfer; vadose zone; soil water movement; California
Abstract:
... Vapor movement is often an important part in the total water flux in the vadose zone of arid or semiarid regions because the soil moisture is relatively low. The two major objectives of this study were to develop a numerical model in the HYDRUS-1D code that (i) solves the coupled equations governing liquid water, water vapor, and heat transport, together with the surface water and energy balance, ...
DOI:
10.2136/vzj2006.0007

14. The Dual Gravimetric Hot-Air Method for Measuring Soil Water Diffusivity

Author:
J. S. Tyner; L. M. Arya; W. C. Wright
Source:
Vadose zone journal 2006 v.5 no.4 pp. 1281-1286
ISSN:
1539-1663
Subject:
soil pore system; diffusivity; water; measurement; analytical methods; clay loam soils; silt loam soils; soil water content
Abstract:
... The hot-air method provides rapid measurement of a soil's unsaturated hydraulic diffusivity function. The original method consists of blowing hot air across one end of a soil column for a short period, and then quickly extruding, dissecting, and oven drying the soil to provide the soil water content profile, which is used to calculate the soil's unsaturated hydraulic diffusivity. This research pre ...
DOI:
10.2136/vzj2006.0079

15. Tomographical Imaging and Mathematical Description of Porous Media Used for the Prediction of Fluid Distribution

Author:
P. Lehmann; P. Wyss; A. Flisch; E. Lehmann; P. Vontobel; M. Krafczyk; A. Kaestner; F. Beckmann; A. Gygi; H. Flühler
Source:
Vadose zone journal 2006 v.5 no.1 pp. 80-97
ISSN:
1539-1663
Subject:
porous media; sand; soil pore system; computed tomography; image analysis; mathematical models; soil water movement; prediction; unsaturated conditions
Abstract:
... Flow and transport processes in porous media depend on the geometric properties of their pores, where the diameters typically range from micrometers to millimeters. In this study, we mapped the pore structure of glass bead and sand columns using tomography with X-rays, thermal neutrons, and synchrotron radiation. Utilizing X-rays from tubes, we mapped two 2.5- and 5.3-cm-diam. sand samples that co ...
DOI:
10.2136/vzj2004.0177