Study on Control Interface of One-dimensional Vertical Infiltration of Soil

Based on water infiltration of field soil under different structural conditions,the phenomenon was revealed that the control interface of steady infiltration rate of soil was depressed by analyzing and comparing the characteristics and differences of infiltration process between well-structured surface soil with bulk density of 1.2 to 1.4 g/cm3 and particularly loose surface soil with bulk density of 1.0 to 1.2 g/cm3.Positions of infiltration control interface under different conditions of surface soil structures were fixed on the basis of analysis of relations between the bulk density and steady infiltration rate of soil.The results indicate that the control interface of well-structured soil was at the upper layer,while the control interface of particularly loose soil was at the plow pan,and the infiltration type of the former belonged to non-pressure irrigation while the latter belonged to pressure infiltration of unsaturated soil.