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United States Department of Agriculture

Agricultural Research Service

Title: Effect of Soil Aggregate Size Distribution on Water Retention

Authors
item Guber, A - MOSCOW STATE UNIV
item RAWLS, WALTER
item Shein, E - MOSCOW STATE UNIV
item PACHEPSKY, YAKOV

Submitted to: Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 10, 2003
Publication Date: November 7, 2003
Citation: Guber, A.K., Rawls, W.J., Shein, E.V. and Pachepsky, Y.A. 2003. Effects of soil aggregate size distribution on water retention. Soil Science. 168:223-233.

Interpretive Summary: Quantitative information on soil water retention is in demand in hydrology, agrometeorology, agronomy, contaminant transport, and other soil-related disciplines of earth and environmental sciences. Soil aggregate composition is an important characteristic of soil structure and, as such, has been expected to affect soil water retention. Soil aggregate composition had a significant influence for all water retention characteristics; therefore, if aggregate size distribution parameters are available in soil databases or feasible to measure, they can be useful in estimating of soil water retention from soil physical properties.

Technical Abstract: Quantitative information on soil water retention is in demand in hydrology, agrometeorology, agronomy, contaminant transport, and other soil-related disciplines of earth and environmental sciences. Soil aggregate composition is an important characteristic of soil structure and, as such, has been expected to affect soil water retention. Our objective was to see whether and how aggregate size distributions affect soil water retention from saturation to the wilting point. Soil properties were studied for samples of Podzoluvisols, Planosols, Chernozems, Fluvisols, Calcisols, and Gleysols. Cumulative particle size and aggregate size distributions were used in regression trees to see what fractions provide the least heterogeneous groups of samples as judged from values of water retention at matric potentials of -10, -33, and -1500 kPa as well as from van Genuchten parameters of the water retention curves, all on gravimetric basis. Soil aggregate composition provided important grouping parameters for almost all water retention characteristics in this work. Contents of either small aggregates (<0.25 mm, <0.5 mm, <1 mm) or large aggregates (>7 mm, >10mm) were the groupng variables in most cases for parameters of the van Genuchten equation. No aggregate size distribution parameters have been included in the regression tree for the water content at -10 kPa whereas contents of aggregates of medium sizes affect water content at -33 and -1500 kPa. Aggregate size distribution parameters, if available in soil databases or feasible to measure, can be useful in estimating parameters of soil water retention from other soil properties.

Last Modified: 9/29/2014
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