Field evaluation and comparison of two models for simulation of soil-water dynamics

The growing interest in simulation of water and solute movement in soils is in response to the need for development of solutions for various agricultural and environmental management problems. In order to be able to adopt models for simulation of the effects of various soil management practices with confidence, it is important that the capabilities of these models and credibility of their results be tested. In this study, predicted soil-water contents by the simple LEACHW and comprehensive ecosys models are compared against field measurements using TDR during a selected period with heavy precipitation. A detailed examination of actual soil-water status, during and after intense precipitation events showed an underestimation of actual drainage fluxes by LEACHW. Such events contribute most in the production of drainage fluxes. Differences in algorithm adopted by the two models are presented and discussed. The algorithm of ecosys resulted in more dynamic water fluxes between layers, which has resulted in better-predicted results than LEACHW, especially at the soil surface. Overall, performance of the two models was found to be reasonable for prediction of soil-water. Copyright (C) 2003 John Wiley Sons, Ltd.