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| Effects of slope grade and cover of Robinia pseudoacacia on runoff and soil loss from loess slopes under simulated rainfall |
| Song Weifeng1,Yu Xinxiao2,Zhang Ying2 |
| 1.Department of Environmental Science and Engineering,Southwest Forestry College,650224,Kunming;2.College of Water and Soil Conservation,Beijing Forestry University,100083,Beijing: China |
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Abstract The experiment of simulated rainfall was carried out by using the soil taken from the artificial forest of Robinia pseudoacacia from Caijiachuan of Jixian County of Shanxi Province in the Loess Plateau.The young trees of Robinia pseudoacacia were planted as a vegetation cover for the experiment slopes.The amount of runoff and soil erosion was collected from slopes of different slope grades with the cover of Robinia pseudoacacia.The results showed that under a given condition of certain rainfall intensity and slope grade,with increasing of slope grade,the generation of runoff and soil loss starts earlier,the runoff velocity is higher,the crown interception percentage and the runoff amount increases,the soil loss yield increases;The relation between the crown interception of forest and the slope grade is I=29.556α-0.311(R2=0.987 4),and the relation between the soil loss from covered slope and the slope grade is W=0.116 84α3.005 9(R2=0.979 5);Under the same condition of slope grade,the runoff and soil loss from Robinia pseudoacacia covered slope is less than that from the bare soil slopes,showing a difference of 15%-25% in the average velocity of runoff,15%-48% in runoff,10%-117% in soil loss,55.5%-133% in the average sediment concentration.
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Received: 27 August 2007
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