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United States Department of Agriculture

Agricultural Research Service

Title: Unsaturated Soil Hydraulic Properties in the Region Near Saturation

item Logsdon, Sally

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: October 24, 1997
Publication Date: N/A

Technical Abstract: Several techniques can be used to obtain unsaturated soil hydraulic properties in the wet end of the curve. Tension infiltrometers determine unsaturated hydraulic conductivity as a function of negative head, K(h), which presents a hysteresis problem. Although individual measurements may be rapid, there is large spatial and temporal variability, necessitating a large number of samples. To obtain subsurface measurements, destructive pits must be dug. The measurements can be combined with a tedious rotated core desorption procedure to get water content (theta) as a function of h for both ascending and descending curves, and hence K(theta). These measurements have shown that near saturation, there is a large change in K with a small change in theta. This wet region may need to be described separately from the rest of the theoretical curve, or with multiple inflections in the curve.

Last Modified: 4/21/2015
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