紫色土坡耕地降雨入渗试验研究

在田间条件下,利用人工模拟降雨研究了坡度、降雨、耕作方式对紫色土坡耕地入渗过程的影响.试验结果表明:雨强对入渗过程有重要影响.当雨强在19.62～111..69 mm/h之间变化,稳定入渗率随雨强增加而增大.坡度对入渗的影响比较复杂.在5°～25°范围内,随坡度增加,稳定入渗率表现出升-降-升的变化趋势,在10°与20°分别存在极大值与极小值.中耕显著增加了水分入渗,特别在高强度降雨下,中耕使稳定入渗率增加1倍以上,入渗补给系数增大50%以上.入渗率随降雨历时增加而减小,二者关系可以用乘幂函数描述.累积入渗量可以用降雨历时的线性函数来表示.

Experimental study on rainfall infiltration in sloping farmland of purple soil

In field conditions, rainfall simulation experiments were conducted to study the influence of slope, rainfall and tillage on infiltration in sloping farmland of purple soil. The results indicate that the rain intensity has significant effect on infiltration. When the rain intensities change from 19 to 111 mm/h, stable infiltration rates get higher with rain intensities increasing. The relationship between slope gradient and infiltration is very complex. When slope gradients change from 5° to 25°, the stable infiltration rate displays a tendency of increasing first, decreasing then and increasing again. Stable infiltration rate reaches the maximum and minimum when slope gradient equal to 10° and 20° respectively. Compared with under non-tillage, water infiltration increases under intertillage, especially under the storm events, stable infiltration rate has one fold increase and coefficient of recharge from precipitation increases of more than 50%. Infiltration rate decreases with rainfall duration increasing and their relationship can be discribed by a power function. But the relationship between accumulative infiltration and rainfall duration can be discribed by a linear function.