Influence Of Land Use Types On Slope Soil Erosion Amount In Granit Red Soil Region

Modern soil erosion is a dynamic process under nature and human activities, and become one of main problem of resources and environment nowadays. The soil erosion on slope not only causes land fragmentation and ecological imbalance but also leads to sediment deposition in river, lake and reservoir. The damage is more serious in red soil area with granite. The research is made in Wushui basin of Hengyang County, Hunan. And the soil properties were investigated in woodlands, open woodlands, abandoned lands, sloping farmlands, and drylands, respectively. The soil anti-erodibility was analyzed, and the features of runoff and sediment were studied in five land use types in 19 precipitation events. The regression equations of runoff and soil erosion based on rainfall characteristic parameters were established. The law of soil and water loss was obtained about five land use types. The results of this thesis can provide scientific bases for localland use management.The results showed that: 1) The effect of land use types on soil properties are obvious. Compared with abandoned lands, drylands and sloping farmlands, both the soil bulk density and the sand contents are smaller with respect to the contents of large water-stable-aggregates increasing, while capillary porosity and water capacity are enhanced for woodlands and open woodlands. 2) There are significant differences in soil anti-erodibility in different land uses. The order of the PCA analysis comprehensive index is woodlands, open woodlands, abandoned lands, sloping farmlands, and dryland. 3) The amount of water and soil loss is different in five land use types in precipitation events. The abandoned lands ranked first, followed by sloping farmlands, drylands, open woodlands and woodlands for runoff and sediment production of different land use types, produced in 19 rainfall events. The erosion of woodlands and open woodlands are normal, suggesting that the two landuses are effective for both soil and water conservation and ecological protection.4) Compared with abandoned lands, drylands and sloping farmlands, the change of runoff and soil erosion is slow with different precipitation conditions for woodlands and open woodlands. The correlation between soil and water erosion and various factors is also smaller in woodlands and open woodlands. 5) The regression equations based on rainfall characteristics parameters about different land use types were established for forecasting the runoff and soil erosion in Wushui basin.