Analysis of County Scale Cultivated Land Pressure in the Central Region of the Three Gorges Reservoir Area:A Case Study of 27 Towns in Fengjie County,Chongqing

Taking 27 towns in Fengjie County of Chongqing City as focal areas we analyzed cultivated land pressure and discuss correlations between pressure on cultivated land and soil erosion based on the theory of landscape ecology,GIS and using statistical techniques. The results show that the distribution of cultivated land across the study area has different lithology,landform and gradients due to physiographic conditions. The spatial differences in cultivated land pressure are distinct. According to the degree of deviation of the pressure index of cultivated land about 1,we divided the study area into four parts:region of no pressure,fringe area,region of low pressure and region of high pressure. In the northern area, its cultivated land pressure is less than the southern that it was due to the large number of sloping cultivated land, alleviated the pressure of cultivated land. However, from the comprehensive strength of soil erosion, the north is greater than the south. That is to say the ecological damage is serious. Therefore, although a large number of reclaiming sloping cultivated land can temporarily alleviate the pressure of the cultivated land, it can accelerate the speed of the water and soil loss in the long run, causing even severe pressure of cultivated land. Relieving cultivated land pressure in the study area,preserving ecological balance by combining urbanization processes,and promoting the shift to non-agricultural industries solving the problem of food by the allopatric supply are needed. We also recommend protecting cultivated land of middling and classy when we withdraw from cultivated land for ecology and adjusting the agricultural structure to form a situation based on cultivating food crops and animal husbandry,forestry,fruit growing and pharmacy.