HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Poulsen, T. G. Articles by Komatsu, T. Search for Related Content PubMed Articles by Poulsen, T. G. Articles by Komatsu, T. GeoRef GeoRef Citation Agricola Articles by Poulsen, T. G. Articles by Komatsu, T. Related Collections Air Permeability Volcanic Soils Soil Physics

ORIGINAL RESEARCH

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

^a Section for Environmental Engineering, Dep. of Life Sciences, Aalborg University, Sohngaardsholmsvej 57, DK-9000 Aalborg, Denmark
^b Dep. of Hilly Land Agriculture, National Agricultural Research Center for Western Region, Ikano 2575, Zentsuji, Kagawa, 765-0053, Japan
^c Dep. of Biological and Environmental Sciences, Graduate School of Science and Engineering, Saitama University, 255, Shimo-okubo, Sakura-ku, Saitama, 338-8570 Japan. T.G. Poulsen, currently: Section for Environmental Engineering, Dep. of Life Sciences, Aalborg University, Sohngaardsholmsvej 57, DK-9000 Aalborg, Denmark
^* Corresponding author (tgp{at}bio.aau.dk)

Received 12 December 2005.

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 accurately describe data for both soil water retention and all three transport parameters as functions of fluid phase contents in undisturbed soil with bi- or multimodal pore structure is required for numerical simulation studies. In this study, a bimodal probability law (BPL) model with a total of six fitting parameters is compared with new and literature data for soil water retention and the three transport parameters measured on undisturbed soils. Saturated and unsaturated hydraulic conductivity (K) at six matric potentials (pF) were measured on four volcanic ash soils (Andisols) where data for soil water retention, air permeability (k_a), and relative gas diffusivity (D_p/D₀) were already available. The BPL model accurately described data for soil water retention and the three transport parameters (K, k_a, D_p/D₀) for the four Andisols and other soils with bimodal porosity behavior. BPL model parameters did not correlate well between transport processes, however, an existing model for relating saturated hydraulic conductivity to air permeability at –100 cm H₂O matric potential performed well for 10 bimodal Andisols. Results indicate that relations between fluid phase transport parameters at given matric potentials may be valid across soil types and useful in the BPL model.

Abbreviations: BPL, bimodal probability law

This article has been cited by other articles:

				T. G. Poulsen and H. Blendstrup Predicting Air Permeability in Porous Media with Variable Structure, Bulk Density, and Water Content Vadose Zone J., November 26, 2008; 7(4): 1223 - 1229. [Abstract] [Full Text] [PDF]

				A. C. Resurreccion, P. Moldrup, K. Kawamoto, S. Yoshikawa, D. E. Rolston, and T. Komatsu Variable Pore Connectivity Factor Model for Gas Diffusivity in Unsaturated, Aggregated Soil Vadose Zone J., April 14, 2008; 7(2): 397 - 405. [Abstract] [Full Text] [PDF]