The Simulation Research On The Soil Water Infiltration Process Under The Drip Irrigation

Research on soil moisture movement of drip irrigation under the condition of point sources, is the right design system and the premise and basis of field crops to high water management. In order to understand the movement of soil moisture and water distribution of drip irrigation, the soil water content in the process of soil water movement was monitored continuously by multicenter soil water apparatus and the data were recorded timely for non-crop growth under the conditions of the two-point source drip irrigation. This paper studied initial soil water content, drippers space, dripper discharge and dripper water on soil moisture content, shape and range of wetting, and the effect of soil moisture movement on interference effect of two-point source infiltration. Taking into account the distribution of soil moisture infiltration overlap in humid and distribution, to determine appropriate dripper discharge and dripper space of the sandy-loam soil, for the irrigation system designed to provide reliable and reasonable theory. The main results are as follows:(1) The horizontal and vertical movement distance of soil wetting front accorded good power function relation with infiltration time on the intersection side and underside of dripper; at the beginning of infiltration, movement velocity of soil wetting front is faster, with the extension of infiltration, movement velocity decreases, and the vertical direction of the wetting front movement velocity is greater than the horizontal direction of the wetting front movement velocity.(2) Under the same conditions, the wetting distance of soil on the intersection side was bigger than un-intersection side, and the region was larger than single-point source of infiltration. The soil moisture of wetting front on intersection side is bigger 2%-3% than the soil moisture of same depth, but not more than field moisture capacity.(3) When dripper discharge, dripper space and infiltration time are specified, the wetting front movement velocity and range of high initial soil water content is greater than low initial soil. With the initial soil water content increasing, the range of high moisture content areas is increase, soil water content is increase at the same location also.(4) When dripper water are specified, small dripper discharge of the range of wetting front slightly larger than the larger dripper discharge, but with the dripper discharge increasing, soil water content is increase at the same location. Dripper discharge are specified, the shorter dripper space is, the greater degree of superposition, the surface of the moist of same dripper water is smaller, rate of the downward movement is fast, wetting is narrow and deep.(5) Considered ratio of the horizontal and vertical movement distance wetting front, irrigation time, re-distribution process and interference effect, in drip irrigation system design and selection, the dripper discharges is to choose the larger emitter, the dripper space should choose a smaller distance to the sandy-loam soil with strong infiltration ability. For the dripper discharges of 4.0L/h of drip emitter, the dripper space 40cm more appropriate choice.