Dynamic Study On Soil Erosion In Heilongjiang Based On USLE Model

The impact of human activities on environment and global change grow deeply. The erosion of the soil was accelerated because of unreasonable land utilization and the climatologic change. It is a big threat to ecological security and habitation, and it will stunt the sustainable development of economy and society. In this paper, combining the characteristic of study area, several kinds of erosion of soil models were compared. At last the Universal Soil Loss Equation (USLE) was used to calculate the erosion degree of the soil in Heilongjiang Province in 1990 and 2005.Based on two periods of Land Use Data obtained from the TM Images (a spatial resolution of 30 m) of 1990 and 2005, together with 1:50000 topographic map, SRTM data, the soil data, NDVI data, rainfall data and field investigation data, all the factors of the model's was ascertained, which contain rainfall erosion power(R), soil erosion value(K), terrain factor(LS), water and soil maintenance measures(P), the equation of erosion of soil(USLE) was established, and the parameters were modified. The various factors of soil erosion were overlaid based on remote sensing and GIS platform and the soil loss amount was figured out, which uses a pixel (30m) as elemental. So the spatial distribution of erosion of soil in 1990 and 2005 was obtained.The results showed that the soil erosion area is 6.7251 million hectare in 1990 and 8.9214 million hectare in 2005, which account for 14.22 percent and 18.87 percent respectively of total area. It has a dynamic increase of 4.65 percent in Heilongjiang during fifteen years. The erosion area of mild and severe erosion showed a gradually upward trend. The main soil erosion area of Heilongjiang province is located in Songnen Plain.