Infiltration model for furrow irrigation

Infiltration rates of soils are spatially and temporally variable, which complicates surface irrigation management. The variability is magnified when water supplies are limited because crops in some portions of the field are intentionally stressed. Soil water content and soil cracking effects need to be considered to better model deficit irrigation with surface systems. A two-dimensional (2D) infiltration model that incorporates the effects of surface sealing, soil cracking, and initial soil water content was developed. The model was compared with a finite difference solution of the Richards equation for vertical infiltration for two surface seal conditions. To further test the model, simulated data were compared with field experiments. Including infiltration through cracks provided a better agreement between observed and simulated data than when cracks were ignored. Simulations showed that the majority of the infiltration through cracks took place during the first few minutes of infiltration. In the future the infiltration model will be combined with other models to simulate deficit irrigation management for surface irrigation systems.