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.