Lateral hydraulic performance of subsurface drip irrigation based on spatial variability of soil: Simulation

Abstract

Soil physical properties (initial water content, bulk density, and mass fractal dimension) have a major influence on subsurface drip capillary water systems. The spatial distribution of lateral hydraulic performance varies along with the spatial variability of soil and is thus highly complex. In this paper, initial soil water content, soil bulk density, and mass fractal dimension generated according to a Gaussian distribution were used as input variables to a nonlinear lateral hydraulic mathematical model of subsurface drip irrigation. The numerical simulation indicated the following. 1) The greater the initial moisture content, soil bulk density and mass fractal dimension, the smaller was the lateral distribution of emitter discharge, and the smaller was the deviation rate of lateral flow. 2) The greater the standard deviation of initial moisture content, soil bulk density, and mass fractal dimension, the higher was the deviation rate of lateral flow, and the more laterally dispersed was the emitter discharge. 3) The greater the initial moisture content, soil bulk density, mass fractal dimension, and inner lateral diameter, the greater was the uniformity of lateral flow; The higher the inlet lateral pressure and emitter spacing, the lower was the uniformity of lateral flow; The uniformity of lateral flow increased with slope in the range −0.0003 to 1 and decreased with the increase of slope in the range 0–0.0005. The improved lateral hydraulic model by taking into account the influence of soil physical properties on subsurface drip capillary water systems, which permits identification of the critical points of the irrigation lateral