Field Evaluation of Layered Green-Ampt Infiltration Model Considering Temporal Variation of Physical Properties

Abstract

A layered Green-Ampt infiltration model considering temporal variation of tilled soil was evaluated with a field experiment on a freshly tilled soil and a soil planted in soybeans under natural rainfalls. Field tests were conducted on a sandy loam soil for two years (1989 to 1990). Temporal variation due to rainfall since last tillage of porosity, hydraulic conductivity and capillary pressure on tilled soil was investigated in 1989 and incorporated into the model as a function of cumulative rainfall energy and porosity. Field data from 1989 were used for model calibration and data from 1990 were used for model verification. A parameter optimization technique was used to calibrate three model parameters, surface roughness, rainfall kinetic energy and final crust conductivity. Using the calibrated parameters from 1989, the model was partially verified with six rainfall events in 1990. The simulated results of the layered model were in good agreement with measured data.