Evaluating the effect of initial soil moisture content on the infiltration characteristics using Empirical and Hydrus 1D Models

Abstract In irrigation water management, it's critical to understand the infiltration rate and its properties. The study aimed to evaluate the ability of some empirical equations and Hydrus 1D models to predict soil infiltration and evaluate the effect of initial soil moisture content on infiltration characteristics. The experiment was conducted at Arba Minch demonstration farmland using a double-ring infiltrometer, and the performance of the various infiltration models (Horton’s, Philip’s, Kostiakov, and Modified Kostiakov) and Hydrus 1D were evaluated in the study area at five different initial water contents. The results showed that the Horton and Hydrus 1D models were fitted with the observed infiltration for the soil with three initial water contents (0.13, 0.256, 0.31, 0.354, and 0.375), and the goodness of fits was evaluated by R2 and RMSE with a range between 0.9967–0.997, 0.93–0.94 and 0.0054–0.006 and 0.024, respectively. Hence, Horton and Hydrus 1D, models could be used successfully to evaluate the cumulative infiltration of soil for the study area. Therefore, in this study, the Hydrus 1D model well captured the infiltration rates at different initial soil moisture contents.