SIMULATION OF SOIL WATER DYNAMICS IN LAYERED SOILS

Abstract

A numerical model of soil water dynamics was devised to simulate infiltration, drainage, evaporation and water storage in texturally layered profiles. The layers consisted of sandlike, loamlike and claylike soil of known hydraulic properties. Data presented on the flow patterns of the variously stratified profiles illustrated the interactions between soil and weather variables which govern profile water storage. Fine-textured layers tended to impede infiltration but may promote drainage of overlying layers. Top layers of coarse texture tended to inhibit evaporation. Since the relative hydraulic conductivities of layers of different textures varied as soil moisture suction changed, it is difficult to predict the dynamic behavior of composite profiles without the benefit of a comprehensive simulation model. Shortcomings of the present model are discussed.