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United States Department of Agriculture

Agricultural Research Service

Title: Effects of Soil Structure on Water Retention

Authors
item Rawls, Walter
item Pachepsky, Yakov - DUKE UNIVERSITY
item Sobecki, T - USDA, NRCS
item Lin, H - UNIV WISC-STEVENS POINT

Submitted to: American Society of Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 28, 1999
Publication Date: October 28, 1999

Technical Abstract: Procedures for predicting soil water retention have been developed to use various levels of soil information; however, soil survey qualitative structure class which is reliably estimated in the field and part of every soils description has never been incorporated into the procedures. Using a national soil database, we investigated the usefulness of incorporating the eeffect of soil structure (grade, size, and shape) on the prediction of water retained at -6 kPa, -10 kPa, -33 kPa, and -1500 kPa matric potential. Texture classes were the most important in describing water retention, but within a texture classes soil structure primarily shape and grade had a significant effect. The overall order of importance of structure classes are shape, grade, and size; however, for water retention less than -33 kPa, size and grade are most important; while for water retention greater than -33 kPa, shape and grade are the most important. Shape and grade were found to be most important in the surface horizons. Soil structure information was not important when using quantitative information such as percent sand, silt, clay, organic matter, and bulk density.

Last Modified: 10/25/2014
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