Modeling of Wetting Pattern Under a Linear Drip Source Buried in Layered Soil

Abstract

This study aims to model the wetting patterns of the homogeneous and stratified soil profile, and to derive an equation to estimate the discharge rate during the application time. The study included conducting 8 experiments to monitor the progress of the wetting patterns over time in a homogeneous and stratified soil profile. Two types of soils were used (silty clay loam and sandy Loam). The emitter was installed at a depth of 45 cm below the soil surface, and soil profiles were prepared in two different sequences and the location of the interface between the soils was changed (at the dripper, 10 cm below the dripper, 10 cm above the dripper). The results showed that there is a good agreement between the measured and estimated advancement distances, where the determination coefficient R2 ranges between 0.826 to 0.989. Moreover, the results showed that the emitter discharge gradually decreases and continues to decline with the continuation of the operating time until it reaches an almost constant value. This reduction in emitter discharge increases by increasing the clay content, soil bulk density, emitter depth, and initial moisture content. The results also showed that the largest wetting front advance distance in the horizontal and vertical directions was in the sandy loam soil profiles, while it was the least valued in the silty clay loam profiles for the same operating time. The interface between the layers also helped in the horizontal and vertical diffusion, especially when the silty clay loam soil was placed below the dripper, which helped in the spreading of water in the horizontal and vertical direction upwards.