Abstract
Hysteretic behavior between soil matric potential and water content relationship is reviewed in concern with its models. Mechanistic models, namely (1)inkbottle model,(2) contact angle model, (3) air entrapment and solution/dissolution model, and ⑷ capillary condensation model, have been proposed to explain the hysteresis. However, none of these models has explained quantitative aspects of the hysteresis so far. Alternatively, quantitative models involving empirical ones, namely (1)domain model coupled with similarity hypothesis, (2) interpolation model,(3)linear model, and (4) parameter scaling model, were incorporated into numerical simulation of soil water dynamics. In these models, the domain model with similarity hypothesis appears to be the most appropriate for the reasons that which has theoretical background, good estimation in high hydraulic conductivity area, and no “pumping” effect To clarify effects of soil water hysteresis under in situ conditions and to improve the quantitative models applicable to long-term monitoring of soil water movement are in great necessity.
