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| Runoff and sediment yield on slope land in initial stages of conversion of cropland to forest in Northwestern Hunan Province |
| Zhou Gang1,2,Tian Yuxin2,Chen Guoyu3,Fu Zhengliang3,Bao Wen3 |
| 1.College of Soil and Water Conservation,Beijing Forestry University,100083,Beijing;2.Hunan Forestry Academy,410004,Changsha;3.Soil and Water Conservation Monitoring Station of Hunan Province,410007,Changsha:China |
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Abstract In order to evaluate ecological benefits of conversion of cropland to forest in Northwestern Hunan Province scientifically,11 types of conversion of cropland to forest were studied with permanent investigation in 3 rock type areas in Rvrezai small watershed there.The results showed that,1)Both the surface runoff and sediment yields were reduced on the slope lands of afforestation,29.45% of surface runoff and 47.02% of sediment were reduced in the board-shale areas,56.54% of surface runoff and 64.04% of sediment were reduced in the granite areas with terracing,14.16% of surface runoff and 36.27% of sediment were reduced in the lime-rock areas in initial stages of conversion of cropland to forest.2)The surface runoff and sediment yields were reduced greatly by terracing,and average surface runoff and sediment yields on terrace is only 34.92% and 3.66% of that on slope land respectively.3)The surface runoff and sediment yields were decreased greatly with the rainfall declining.The surface runoff and sediment yields caused by the rainfall more than 50mm were 52.17%、70.79% respectively of that in the whole one year.
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Received: 07 November 2007
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