Study On The Coupling Relationship Of Landscape Pattern And Soil Erosion In Watersheds Of Farming-pastoral Zone

The research on the coupling relationship between the soil erosion and the land use pattern in small watershed has been one of the most important science problems which concerned by the international scientists. The combination of the soil loss in small watershed, the effective utilization and the evolution of the land cover structure is the important content for agricultural sustainable development. It is also the weak point of soil erosion research. The change of land utilization cover is an important element in the changes of landscape structure. The land use pattern links with the soil and water loss tightly, the changes of land use can decrease or increase the runoff and the amount of soil erosion. Using theory and methods of the landscape ecology, the principle and methods of GIS, revealing the relationship between the watershed landscape structure and the soil erosion to offers some basis for the ecologic environment reconstruction and the sustainable development.This paper has taken the Dagoutou watershed in Naiman country of Inner Mongolia of Farming-pastoral zone as the research object. With the help of the GIS application software and the Landscape Structure Analysis software, We made a partial treatment and analysis, imitated the soil erosion character in watershed and the relationship with its the forest-grass vegetation; analyzed the change of soil erosion in different landscape structures in the river valley,and then studied the advantages and disadvantages of the land use pattern in the northeast and the analysis on the optimized pattern. The result showed that the space structure forms of landscape patch and the connectivity are the key of the erosion and the sand creating, it can decrease the runoff and holding soil by adjusting the land use pattern.Used the Arcview software, it stacked the land use pattern dynamic graph and soil erosion dynamic graph of Dagoutou watershed in 1986, 1997 and 2005, the coupling relationship between the soil erosion in small watershed and the land use pattern is establishmented,it showed that micro-erosion happens in every land use pattern in the three periods.In order to analyze the influence of the landscape structure dynamic, We had set scenery model. We showed and analyzed the situation of the change of the soil erosion in different watershed landscape structures. The result showed: the soil erosion amount in the eight covers changes regularly, the forest-grass vegetation recovery is the main way to watershed management and soil erosion treatment. With the area of the forest-grass vegetation and the cover rate are increasing, their influences on the soil erosion are stronger. So, it can prevent soil erosion and induce the sediment amounteffectively. At the same time, the combination of the vegetation measures and the engineering measures can avoid appearance of the critical value of the forest-grass vegetation. So, it not only can guarantee the ecological benefit,but also the economic benefit, and will get twice the result with half the effort.