雨前土壤含水量对紫色土坡耕地地表产流过程的影响

Effect of Soil Water Content before Rainfall on Surface Runoff Yield Process in Farmland in Purple Slope Land

[目的]为紫色土侵蚀的相关研究提供参考。[方法]试验在盐亭站7个不同坡度、不同土层厚度的径流小区进行,每小区进行两种土壤含水量(10%和20%)的降雨试验,研究雨前土壤含水量对紫色土坡耕地地表产流过程的影响。[结果]当雨前土壤含水量较高时,地表产流较快且径流上升较快,在降雨6 min后开始产流,产流10 min后地表径流达到稳定;而土壤含水量较低时,降雨10 min后才开始产流,产流25 min后地表径流达到稳定;当产流稳定后,2种土壤含水量条件下的稳定入渗率差异不明显,相对偏差小于10%。雨前土壤含水量较高时,地表径流量较大。[结论]雨前土壤含水量对地表产流过程的影响主要体现在降雨初期。

[ Objective ] The study was to provide the reference for the related research of purple soil erosion. [ Method ] The test was clone in 7 runoff plots with different soil slopes and thicknesses in Yanting station. In each spot the rainfall experiments with 2 kinds of soil water content（ 10% and 20% ）was made, and the effect of soil water content before rainfall on the surface runoff yield process in farmland in purple slope land was studied. [ Result] When the soil water content before rainfall was higher, the surface runoff yield was faster and the runoff rose more quickly. The runoff yield began after rainfall for 6 min and the surface runoff was stable after runoff for 10 min. When the soil water content was lower, the runoff began after rainfall for 10 min, and 25 min later runoff got stable. When the runoff yield was stable, the stable infiltration rate of 2 kinds of soil water content hadn no obvious difference and the related deviation was smaller than 10%. When the soil water content before rainfall was higher, the surface runoff was bigger. [ Conclusion ] The effect of soil water content before rainfall on the surface rainfall runoff process was embodied mainly in the early period of rain.