Study on Soil Erosion Law of Typical Small Watershed-Luoyugou Watershed in Gully Region of the Loess Plateau

摘要

The basic characteristics of soil erosion in Luoyugou Small Watershed are analyzed in this paper. Based on both methods of fixed — point observation and typical investigation, the watershed is divided into 3 erosion regions, 9 erosion types and 6 erosion belts. The soil erosion amount on slopes was measured and calculated, results of which were verified by using Universal Soil Loss Equation, and moreover, the gravity erosion amount in canals was calculated and its source was analyzed, which shows that the proportion of slope to canal of annual sediment discharge is 50:50 in the years of normal sediment output, and the ratio of output and transportation of slope, canal and gravitational erosion is 1.0, 0.47 , O. 68 and the average is 0. 68 in small watershed. Accumulative ratio of output and transportation in canal presents peak value in the trunk canal of level 4. Slope is the main source of flood and fine silt, and the canal is the centralized origin of bed load and gravitational erosion. The study provides theoretical basis for farther disclosing the law of soil erosion and water loss in the gully region of the Loess Plateau.