Impact of alteration in soil hydraulic variables on collective infiltration using HYDRUS-1D

Following HYDRUS-1D model calibration of the infiltration process, the impact of a 20% change in soil hydraulic parameters (0.8 to 1.2 parameter values) on cumulative infiltration was examined. Infiltration is most sensitive during the short irrigation period under intermittent irrigation when the soil is dried and wetted successively, whereas it is the most sensitive during the long irrigation period under daily irrigation when the soil is wetted continuously. In fact, as soil permeability increases, infiltration becomes more sensitive to parameter changes. The daily and intermittent irrigations with poor irrigation water quality, respectively, were found to have the highest and lowest values of the sensitivity index. The findings indicated that Ks was the parameter that was the most sensitive, followed by θs, n, α and θr with l being the least sensitive parameter. As a result, Ks and θs will be the only two parameters used to optimise the model. © 2024 Inderscience Enterprises Ltd.