雨强对黄土坡面土壤水分入渗及再分布的影响

基于典型黄土的坡地人工降雨实验，对比研究了降雨、入渗及再分布规律；以雨强为主要影响因素，分析了降雨入渗及水分再分布过程中水土物质迁移的定量关系．结果表明，雨强变化对黄土坡面降雨入渗及土壤水分再分布的微观水分运动过程具有重要影响．雨强增大时，入渗和再分布湿润锋均随降雨历时延长而逐渐增加，但水分再分布过程的湿润锋增加速率比入渗慢得多；入渗湿润锋与时间关系可用幂函数表示，同时可表示为雨强的幂函数关系．再分布湿润锋与时间也存在定量关系．雨强越大，初始和稳定的土壤水分入渗率越高，累积入渗量随降雨时间增加得越快．此外，雨强越大，坡顶与坡脚湿润锋深度差异越小，坡面再分布过程的土壤含水量在各层的差异和递减趋势越明显．

Effects of rainfall intensity on rainfall infiltration and redistribution in soil on Loess slope land

With simulation test, this paper studied the patterns of rainfall infiltration and redistribution in soil on typical Loess slope land, and analyzed the quantitative relations between the infiltration and redistribution and the movement of soil water and mass, with rainfall intensity as the main affecting factor. The results showed that rainfall intensity had significant effects on the rainfall infiltration and water redistribution in soil, and the microcosmic movement of soil water. The larger the rainfall intensity, the deeper the wetting front of rainfall infiltration and redistribution was, and the wetting front of soil water redistribution had a slower increase velocity than that of rainfall infiltration. The power function of the wetting front with time, and also with rainfall intensity, was fitted well. There was also a quantitative relation between the wetting front of rainfall redistribution and the duration of rainfall. The larger the rainfall intensity, the higher the initial and steady infiltration rates were, and the cumulative infiltration increased faster with time. Moreover, the larger the rainfall intensity, the smaller the wetting front difference was at the top and the end of the slope. With the larger rainfall intensity, both the difference of soil water content and its descending trend between soil layers became more obvious during the redistribution process on slope land.