Soil erosion dynamics of Sanjiang Plain in past 50 years

During the past 50 years, Sanjiang Plain, which is one of the most important areas for commercial production of China, has experienced soil loss due to improper land use .For this study land use maps for 1954 1976 1986 and 2000 were obtained based on Landsat satellite image and historical topographic map along with expert knowledge. DEM data, soil maps and rainfall data were also obtained. Using GIS and USLE, we selected appropriate methods to calculate each factor in the USLE and evaluated the soil erosion of the Sanjiang plain over the past 50 years .Results showed that light erosion dominated the Sanjiang plain and acute soil erosion was almost nonexistent .The area affected by soil erosion has increased over the past 50 years, with eroded area in 2000 was 1 .4 times of the area in 1954.The intensity of soil erosion has increased especially high-intensity erosion level for which the ratio of soil erosion increased more than that of low-intensity erosion. Muling basin had the largest eroded area and Naolihe basin had the largest increment of erosion area. This study provides a scientific basis for erosion control in the Sanjiang plain and provides reasonable suggestions for management and decision-making in terms of agricultural and development policies.