Abstract
The one-step outflow process was numerically analyzed for a soil in which water diffusivity was an exponential function of volumetric water content especially for durations after the initial stage. 1) The soil water diffusivity ratio was well expressed with a one-term power function of distance from the open end. The power was greater than 2 in the initial stage, came down to 2.00 quickly and was maintained at this value throughout the middle stage, and then gradually decreased to 1.75 during the final stage. 2) The reciprocal of the soil water diffusivity at the open end was almost a linear function of time during the middle stage. 3) The time course of the cumulative volume outflow was expressed parametrically with two algebraic functions of the open end water diffusivity ratio. 4) The equilibrium soil water content can be estimated from the outflow data with the algebraic functions.
