积水条件下连续和间歇供水对土壤入渗特性的影响

土壤入渗与地表径流、土壤侵蚀、土壤养分流失和面源污染等密切相关。通过对紫色土中的黏壤土进行不同积水深度下连续供水和相同积水深度下间歇供水的土柱模拟实验,对紫色土一维垂向入渗特性进行了研究。结果表明,当积水深度为1～10cm时,积水深度对累积入渗量及入渗率基本上没有影响;积水深度一定时,连续供水下土壤容重和初始含水率对紫色土入渗特性有较大影响,累积入渗量和入渗率随土壤容重和初始含水率的增加而减少;积水深度一定时,间歇供水下紫色土入渗曲线为间断的非连续曲线,第1周期与连续供水的入渗过程一致。从第2周期开始,间歇供水的累积入渗量及入渗率均小于同条件下的连续供水,间歇供水的紫色土入渗特性与供水周期及循环率等密切相关。

Effects of Continuous and Intermittent Water Supply on Infiltration

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.