Analytical Description and Evaluation of Soil Infiltration Processes Under Horizontal Moistube Irrigation

In the optimal design and operation of moistube irrigation systems, a wetted body and its components are important factors. This study presents an analytical characterization of the soil wetted body under horizontal moistube irrigation. In the laboratory experiment, the temporal and spatial changes in the wetted body during irrigation were observed. Specifically, the maximum wetting distances in the horizontal, vertical upward, and vertical downward directions on the soil profile were measured every 30 min. Additionally, images documenting the wetted body’s changes at different time points were recorded throughout the experiment. On this basis, by locating the soil profile of the wetted body in a coordinate system, the main motion equations describing the temporal and spatial changes in the wetted body’s soil profile were derived. Through integral processing of these motion equations, an analytical model for the wetted body under horizontal moistube irrigation was constructed. Finally, the model was validated using the experimental data. The results show that the model outcomes are consistent with the natural movement of water in the soil. Therefore, when characterizing the size of the wetted body under horizontal moistube irrigation using the soil profile area, the proposed method, which involves analyzing the shape and components of the wetted body’s soil profile at different time points and determining its soil profile size by integrating four distinct parabolas, is feasible.