SCALING OF INFILTRATION AND REDISTRIBUTION OF WATER ACROSS SOIL TEXTURAL CLASSES

Authors: Ahuja, Lajpat; Kozak, Joseph

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/14/2004
Publication Date: 11/2/2004
Citation: Ahuja, L.R., Kozak, J.A. 2004. Scaling of infiltration and redistribution of water across soil textural classes. ASA-CSSA-SSSA Annual Meeting Abstracts. Seattle, WA. 10/31-11/4,2004.

Interpretive Summary: Results with a empirically based one-parameter model showed that the pore-size distribution index (lambda) described in the Brooks and Corey formulation of soil hydraulic properties can scale the soil-water retention curves below the air-entry pressure head values across dissimilar soils. It is shown here that the'nair-entry pressure and saturated hydraulic conductivity are also strongly related to lambda, and thus all hydraulic parameters may be estimated from lambda. The major objective here was to examine how these relationships to lambda lead to relationships for infiltration and soil water contents during redistribution across soil textural classes. The Root Zone Water Quality Model simulated infiltration for four rainfall intensities and redistribution for four initial wetting depths in eleven textural class mean soils. All infiltration results across textural classes were scaled quite well by using the lambda-derived normalization variables based on the dimensional analysis of the Green-Ampt model. Additionally, we present infiltration, as well as redistribution, as explicit functions of lambda. These functions can be used to approximately estimate infiltration and soil water contents across soil types for other soils and conditions by interpolation. This study enhances our understanding of the soil water relationships among soil textural classes.

Technical Abstract: Results with a empirically based one-parameter model showed that the pore-size distribution index (lambda) described in the Brooks and Corey formulation of soil hydraulic properties can scale the soil-water retention curves below the air-entry pressure head values across dissimilar soils. It is shown here that the'nair-entry pressure and saturated hydraulic conductivity are also strongly related to lambda, and thus all hydraulic parameters may be estimated from lambda. The major objective here was to examine how these relationships to lambda lead to relationships for infiltration and soil water contents during redistribution across soil textural classes. The Root Zone Water Quality Model simulated infiltration for four rainfall intensities and redistribution for four initial wetting depths in eleven textural class mean soils. All infiltration results across textural classes were scaled quite well by using the lambda-derived normalization variables based on the dimensional analysis of the Green-Ampt model. Additionally, we present infiltration, as well as redistribution, as explicit functions of lambda. These functions can be used to approximately estimate infiltration and soil water contents across soil types for other soils and conditions by interpolation. This study enhances our understanding of the soil water relationships among soil textural classes.