RISK ASSESSMENT OF SOIL EROSION AND EFFECTS ON SOIL NUTRIENTS IN RED ERODED SOIL OF SOUTH CHINA

摘要

Soil erosion which endangers the human survival and development has been an important environmental problem around the world for a long time. The complexity and diversity presents in Zhuxi Small Watershed which is one of the thirty typical monitoring watersheds in China. The information which include rainfall, slope, soil, vegetation and land use, was obtained by combining 3S techniques with field investigation and the evaluation model on soil erosion risk was established by using these data. The soil erosion risk was divided by 5 types, including micro-degree risk, light risk, moderate risk, high risk and violent risk, and the distribution map of soil erosion risk was compiled also. The results showed that: Light risk and moderate risk were the main types and their area proportion was above 90%, areas of high risk and violent risk accounted for only 6.72% and 0.2% respectively, it could be inferred that ecosystem was not very vulnerable and unreasonable human activities could be the main reasons for the strong soil erosion in this region. Soil erosion risk type was the dominant factor affecting the contents of soil nutrients which could decrease soil nutrient contents Comparisons with field investigation showed that the result was in conformity with actual conditions proving the reasonability and applicability of the evaluation model.