关键词: 坡度, 侵蚀

Abstract: The effects of slope gradient on slope erosion was through its impacting on slope soil stability,soil depth,soil infiltration,ad slope flow velocity.Field observation shows that with the increase of slope gradient,the stability of soil on slope surface decreases.Under long time erosion of slope flow,soil grains on slope surface become coarser and the depth of soil become thinner.Thus,during raining periods,the volume of infiltration decreases and the volume of runoff increases,which was confirmed by field experiments.Experiment in the suburb of Zhangjiakou City,Hebei Province showed that both the total infiltration and the final infiltration were inversely proportional to slope gradient under 15°.When slope Is great than 15°-18°,the infiltration does not vary with slope obviously.The amount of drop splash is related to rate of drop diameter and depth of surface sheet flow and slope degree.When the depth of sheet flow is less than drop diameters,the existence of sheet flow actually enforces the splash,until the depth of sheet is equal to the drop diameter,when the splash reaches its maximum.Then,the splash reduces as the sheet depth increase.Under certain amount of precipitation,the volume of runoff increases with slope,and so does the depth of sheet flow,until the slope gradient reaches 18.3°(Foster,R.L.and Martin,G.L,1969).h,the drop splash increases with slope gradient and reaches its maximum when slope gradient is 18.3°(Palmer,R.S.,1963).

Key words: Slope gradient, Soil erosion