Experimental Study on Law of Runoff-Erosion-Sediment Yield under Field Simulated Rainfall Condition

Rainfall and runoff are the main dynamic factors which cause soil erosion on the Loess Plateau.Research on processes of rainfall,runoff and sediment yield can serve as development of process-based mode of soil erosion,soil and water conservation,and ecology construction on loess region.The rule of erosion sediment and runoff infiltration and dependency relation were studied under different site conditions using field simulated rainfall trails.The results show that the runoff on barren land were 11 and 1.5 times greater than that on forest grass land and slope farmland and grass land,the sediment production on barren land were 260 and 9 and 2 times greater than that on forest grass land and grass land and slope farmland,the seeping rate of forest grass land were 4 and 3 and 2 times greater than that on grass land and barren land and slope farmland;Cumulative runoff power function increase with cumulative sediment increase,sediment production linearity increase with sediment concentration increase,they have perfectly correlativity;The process of runoff and sediment is divided into 3 stages that develop period and active phase and stable stage;The regulation mechanism of grass land on water and sediment have the water and soil conversation function that direct sediment retaining,and forest grass land have the water and soil conversation function that water storage and sediment.The results are significantly meaningful for understanding the runoff process.The results also can provide reliable experimental support for related model research.