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| Relationship between sediment reduction benefit and control degree of soil erosion in region from Hekouzhen to Longmen |
| Ran Dachuan1,2,Liu Bin3,Bai Zhigang4,Wang Hong5 |
| 1.Water Resource Institute of Yellow River of YRCC,450003,Zhengzhou;2.State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Soil and Water Conservation,Chinese Academy of Science,712100,Yangling,Shaanxi;3.Xifeng Soil and Water Conservation Experimental Station of YRCC,745000,Qingyang,Gansu;4.Suide Soil and Water Conservation Experimental station of YRCC,718000,Suide,Shaanxi;5.Tianshui Soil and Water Conservation Experimental Station of YRCC,741000,Tianshui,Gansu: China |
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Abstract Relationship between sediment reduction benefits and control degree of soil erosion in region from Hekouzhen to Longmen was studied and results indicated:1)sediment reduction benefit positively correlated to control degree of soil erosion, the relationship could be divided into high benefit value zone and low benefit value zone according to the benefit range of sediment reduction,but sediment reduction rates per unit in the two zones are similar.When control degree in the low benefit zone is less than 15%,there is almost no sediment reduction benefit.Therefore,for the four typical tributaries namely "Kuyuhe,Tuweihe,Huangfuchuan and Zhujiachuan",control degree needs to be above 30% if above 10% of sediment reduction benefit is required.2)If the relationship is divided into three zones of high benefit value,medium benefit value,and low benefit value,10% of control degree increase in high benefit value zone will result in 8% increase in sediment reduction.Correspondingly,10% of control degree increase in medium value benefit zone and low benefit value zone will lead to 8% and 3.4% increase in sediment reduction respectively.Therefore,in order to construct the first defense line for soil erosion,low benefit value zone which locates in Kuyehe River basin and Huangfuchuan River basin is commanded to be selected firstly.
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Received: 20 January 2006
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