Through the located observation trial in runoff plot in Suining Water and Soil Conservation Station

using the way of data analyzing

the laws of soil erosion on sloping farmland in Suining group purple soil. The results showsed: runoff is enlarged along with the increase of rainfall

and the relativity between the erosion and the rainfall is unapparent; the erosion thickness of sloping land

erosion amount and the loss amount of nutriment are all become big along with the increase of the cultivated land gradient;y=-30.666-1.326x_1-2.343x_2 23.646x_3 can describe the relation between soil erosion amount and rainfall

meant rainfall density

depth of muddy runoff well.