HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Ahuja, L. R. Articles by Swartzendruber, D. Search for Related Content PubMed Articles by Ahuja, L. R. Articles by Swartzendruber, D. GeoRef GeoRef Citation Agricola Articles by Ahuja, L. R. Articles by Swartzendruber, D.

An Improved Form of Soil-Water Diffusivity Function¹

ABSTRACT

The soil-water diffusivity D() is expressed by a functional form which becomes infinite as the soil-water content approaches a constant value, such as the saturated or near-saturated value. The function begins at the origin, and shows an approximately exponential rise in the intermediate soil-water content range. When combined with a previously suggested form of unsaturated hydraulic conductivity function K(), qualitatively reasonable forms for the relationship between water content and suction head can be inferred. A computer program was developed to determine the characterizing parameters in the function by a least-squares fit to experimental data for horizontal water absorption. The program used an optimum seeking technique with numerical solutions of the flow equations as obtained by Philip's method. For different types of soils and several bulk densities, the new functional form was compared with the commonly used exponential expression for D(), and was found to be more representative, particularly for soils which show a very rapid increase in D() as saturation is approached.

¹ Journal Paper no. 4435, Purdue Univ. Agr. Exp. Sta., Lafayette, Ind. Contribution from the Dep. of Agronomy. Partial support was from funds provided by the US Dep. of Interior, Office of Water Resources Research, as authorized under the Water Resources Research Act of 1964. Presented before Div. S-1, Soil Science Society of America, Aug. 24, 1970, at Tucson, Ariz.

² Post-Doctoral Research Associate, and Professor of Soils, respectively.

Received for publication May 24, 1971. Accepted for publication August 27, 1971.