Effects of Continuous and Intermittent Water Supply on Infiltration Characteristics of a Purple Soil Under Ponding Condition

Infiltration process,in general,is closely related to surface runoff,soil erosion,loss of soil fertility and non-point source pollution.Two series of soil column experiments were performed to study the characteristics of one-dimensional vertical infiltration into a purple clay soil.One was the simulation under the condition of continuous water supply at different ponding water depths and the other was that under intermittent water application at the same water depths.Results indicated that there was no significant effect of ponding water depth on infiltration rate and cumulative infiltration when ponding water depth is between 1 and 10 cm.Soil bulk density and initial water content had great impacts on the infiltration characteristics under the condition of continuous water supply at some ponding depth,which means that infiltration rate and cumulative infiltration increase with the decreased soil bulk density and initial water content.The curves of infiltration into the purple soil are discontinuous under intermittent water application at some water depth.The process in the first period was the same as that under the condition of continuous water supply,and however,infiltration rate and cumulative infiltration were both less than those under the condition of continuous water supply in the second period.The characteristics of infiltration into the purple soil under intermittent water application show significant relation to the cycle and rate of water supply.