Simulated and measured soil wetting patterns for overlap zone under double points sources of drip irrigation

Abstract

Water resource scarcity is a serious problem hampering agricultural development in the arid and semiarid region. Drip irrigation is one of the most useful methods that is widely used in the arid and semiarid region. Intersection is a however, common event under drip irrigation and the crops are always planted in the overlap zone, hence a suitable design and operation of the system is very important for crop yield. In this study, experimental and simulated soil wetting pattern of overlap were investigated for drip irrigation at different emitter discharge, irrigation volume and emitter spacing, respectively. Simulations of the water content and wetting front were close to the observed data. To evaluate the effects of various parameters on wetting, additional simulations were carried out with HYDRUS. After the simulation under the HYDRUS environment, we therefore recommended a larger irrigation volume, larger wetting pattern; and when the emitter spacing is shorter, then the wetting patterns should be larger. Due to the heterogeneity of soil texture, the horizontal and vertical distance are almost uniformly in the loam and silt, inversely in loamy sand.

Key words: Drip irrigation, HYDRUS, intersection, soil wetting pattern.