Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 22, 1998
Publication Date: N/A
Technical Abstract: Equations describing hydraulic conductivity (K) as a function of water content were developed before preferential flow was given much consideration. Recent technique developments have allowed K measurements in soils near saturation, and have shown a large decline in K for a small change in water content. Many popular equations have expected a flat response of K as a function of water content for the region near saturation. The purpose of this study was to combine tension infiltrometers with drainage and evaporation methods for determining K as a function of water content. Undisturbed columns were instrumented with automated time domain reflectometry and tensiometers for measurement of water content and pressure head. The three regions (tension infiltrometer, drainage, evaporation) covered a larger range of the K curve than any one method. A logistic equation described the curve better than existing published equations.