VERIFICATION OF QUICK CAPILLARY RISE APPROACH FOR DETERMINING PORE GEOMETRICAL CHARACTERISTICS IN SOILS OF VARYING TEXTURE

Abstract

Capillary rise experiments were conducted with water in soils of varying texture to verify the validity of the recently proposed Quick Capillary Rise (QCR) approach. We verified it by straight line plots obtained between wetting front rise velocity dZ/dt and the inverse of the wetting front rise 1/Z in the first time segment. The values of the penetration coefficient lM and hydraulic conductivity Ko derived from the QCR approach matched those measured independently. Equivalent pore radius r predicted from the QCR approach was found to be higher and linearly related to mean pore radius re determined experimentally from the soil water desorption curve. The values of pore shape factor G ranged from 121 to 138 in different soils. Soil wettability in terms of Cosa decreased with fineness in soil texture in both QCR and Hammond and Yuan methods. The wetting front potential Z* was found to be much lower than the apparent maximum height of capillary rise Z**. Our study shows that the simple and inexpensive QCR approach may be used to determine geometrical, contact, and hydraulic characteristics in soils of varying texture.