Water-entry value as an alternative indicator of soil water-repellency and wettability

Soil water-repellency is an increasingly important consideration in hydrology. In this paper, we relate the degree of soil water-repellency and wettability to the critical water-entry value of a soil. A water-pending method was used for simple measurement of water-entry value in repellent soils. A tension-pressure infiltrometer method was demonstrated for measuring water-entry value in both repellent and wettable soils. The measurement techniques were used to detect a sudden breakdown of repellency under a sufficiently high water pressure. Experimental results have proven that the water-entry value, in terms of soil water potential, is positive in repellent soils, and negative in wettable soils or soil conditions. The water-entry value is shown to be an easily measured indicator of repellency or wettability that provide an assessment of hydraulic effects of soil physical, chemical and biological properties. (C) 2000 Elsevier Science B.V. All rights reserved.