Soil Erosion and Sediment Yield Models of Different Land Types in Small Basins in the Hilly Loss Region

On the basis of rules of the soil erosion and sediment yield of the hilly Loess region, and through analyses of the data of field observation from 1955 to 1980 and the data of many artificial rainfalls , we built soil erosion and sediment yield equations of different land types, which had abundant types of soil erosion including hillslope, loess, red_soil and cave, then developed the hillslope submodel, the valley slope submodel and the channel submodel. This research made full use of the powerful function of spatial analysis of geographical information system(GIS), and constructed the database of the small basin. We revised the arithmetic according to the complex physiognomy conditions of the Hilly Loess region and abstracted the drainage networks from digital elevation model(DEM). After the models calculation of the image through the interface between the models and the image, we drew following conclusions: slope farming was the primary sources of sediment, and gully slope played the important role in the whole small basin, and the conflux process of water and soil influenced deeply the lower_slope. At the same time, we have finished testing in Yandaogou small basin, and made extension and application in Yanwang small basin.