Effect of Water Supply Pressure on Soil WaterMovement in Different Soil Textures under SubsurfaceIrrigation with Porous Pipe

摘要

Numerical simulation of soil water movement is one of effective measuresto study the dynamic regular pattern of soil water. With the help of HYDRUS-2Dcomputer program, the numerical simulation of soil water transport was conductedwithin the pressures of water supply from 100 cmH2O to 1000 cmH2O in different soiltextures of Meadow Brown Soil under subsurface irrigation with porous pipe in thepaper. Results show that numerical simulations are convergent under the watersupply pressure within 100～1000cmH2O in loam soil, 100～600 cmH2O in loam sandsoil and 100～400 cmH2O in clay soil, respectively. The time for the wetting front ofsubsurface irrigation water reaching into the soil surface, 60cm below and 70cmlateral to the porous pipe buried 30cm soil depth was decreasing with the increasingof water supply pressure. It was monotonously on the decrease within the pressure of100～1000cmH2O and 100～400 cmH2O water supply pressures in both loam soil andclay soil, but invariableness as the water supply pressure over 500cmH2O in loamsand soil. The effect of subsurface irrigation with porous pipe was better as applied inloam soil than in both loam sand soil and clay soil. The rate of water movement wasenhanced as the increasing of water supply pressure within the certain range of waterpressure. The results of determined in field are agreed with those in numericalsimulation.