Research On Landuse Pattern Optimization For The Target Of Controlling Erosion In Watershed

This paper based on the map and table such as land-use map and topographic map and the field data of Baerdungou small watershed in Kulun County, with the use of Geographic Information System(GIS), established database, and used the methods of spatial analysis and mathematical statistics, analyzed the landscape ecology of land use status of the small watershed, proposed many indexes of landscape index, the results showed that: the landscape types were less, there were not relatively obvious dominant landscape types, the patch distribution was more uniform, and the landscape fragmentation was higher in the small watershed.The terrain is very complex in the small watershed, the relationship between terrain, soil physical and chemical properties, soil erosion and land use was close, through analyzing the survey data, the following conclusions can be drawn:(1) The general terrain of the small watershed was higher in north lower in south, the ravine system were fully developed in the region, the channels were cross, and showed a treelike development, the land use types showed a pattern of"not concentrated, not continuity".(2) The soil physical properties and soil water status of cultivated land were the best, that of forestland were slightly inferior, forest and pasture compound took the middle position, secondly for grassplot, the poorest were for agroforestry; on the aspect of soil chemical properties: cultivated land>grassplot>forest and pasture compound>forestland>agroforestry. On the whole, the soil physical properties and soil water status of cultivated land were the best, that of agroforestry were the poorest.(3)Because of the interrupt of human factors, the soil erosion degree of cultivated land, water and other land were low, the soil erosion of grassplot and part of forestland were relatively serious.Combined with geographic information database and field survey data, with the use of comprehensive index method, evaluated the land resource use in Baerdungou small watershed, the evaluation chose 10 evaluation factors such as slope, topography positions, soil organic matter and so on, determined weights by using expert grade method, calculated the synthesis score, by using grading method, cultivated land was divided into four grades, forestland was divided into three grades, grassplot was divided into two grades.Based on the results of land resource evaluation, optimized the land use of Baerdungou small watershed by using linear programming method, through variable set up, condition restriction and analysis of objective function, obtained the optimal mode of land use pattern of the watershed, the optimization results showed that: the area of cultivated land decreased by 7.91% generally, but the cultivated land quality somewhat increased; the area of forestland changed obviously, increased by 14.16% generally; the area of grassplot decreased by 6.38% generally; the area of grassplot had a little decrease, the area of other land increased by 0.32%. The results were accord with the principle of ecological security, local conditions and preventing and controlling erosion, achieved the target of land use pattern optimization in the small watershed.