Abstract
The aim of this study is to evaluate soil water movement and water consumption in crop fields based on the crop root distribution and daily soil evaporation. A nu-merical model based on HYDRUS-1D was introduced to simulate the soil water movement under different distribu-tions of crop root. A concept of dual crop coefficient was used to separately quantify soil evaporation and transpira-tion for the boundary condition of the soil surface and the root extraction. Soil evaporation reduction coefficient was introduced to estimate the soil evaporation reduction with the decrease of soil water content. Field measurement was performed in a broccoli field to verify the model assump-tion. Simulated volumetric water contents near the surface assuming a uniform root distribution were quite different from observed data. Hence simulated and measured wa-ter consumptions according to the soil moisture depletion method did not agree well. When the root growth process and the soil evaporation reduction coefficient were taken in account in the soil water analysis, simulated volumetric water content and water consumption had good agreement with the measured ones.
