Implementation of DRBEM with predictor-corrector for infiltration in four layered heterogeneous soil under impermeable and non-impermeable conditions

This research focuses on the steady infiltration problem in a furrow irrigation channel consisting of four heterogeneous soil layers (Horizon O, A, B, and C), incorporating the root water uptake process. The rectangular irrigation channel is analyzed under both impermeable and permeable conditions. The problem is formulated as a mathematical model using a nonlinear partial differential equation (PDE). After being transformed into a linear PDE, the equation is determined using the Dual Reciprocity Boundary Element Method (DRBEM) combined with a predictor-corrector scheme. The implementation of DRBEM to solve the model is carried out in two stages. In the first stage, the model is solved without considering root water uptake, and the resulting solution is used to estimate the water pressure response function using the predictor-corrector scheme. In the second stage, DRBEM is applied again with the root water uptake process. The numerical solution obtained represents the suction potential value. The study examines water infiltration characteristics across the four heterogeneous soil layers influenced by root water uptake. The results reveal distinct water movement patterns, with the uppermost layer showing divergent behavior and the lowest layer showing convergent behavior. Additionally, the infiltration in impermeable and permeable channels shows that the permeable condition results in greater water infiltration. These suggest higher water absorption, leading to increased soil water content.