Dynamic Monitoring And Decision Analysis On Returning Cropland To Forestry (Grass) Based On RS & GIS

Soil erosion has already become the important factor of restricting sustainable development of economics and society, because of improper land use, land degradation and desertification in China have been aggravating .The project of returning cropland to forestry (grass) is a great project and important method to improve ecological environment and accelerate economic development in China. By using RS and GIS technology based on TM (ETM+) data of 2000, 2002, 2005,1 : 100,000 DEM and 1 : 100,000 soil erosion data, the author discussed the area, distribution and the forest-grassland pattern of returning cropland to forestry (grass) in Pengyang. The study includes four steps: Firstly, it investigated the land use change in the past five years, through getting the land use data by visual interpretation of TM images and extracted the cropland and wasteland in order to monitor dynamic change of returning cropland to forestry (grass) in Pengyang. Secondly, through the research method of spatial analysis of GIS, combining the principle of returning cropland to forestry (grass), the author anglicized the area and distribution of cropland under the condition of soil erosion, aspect, slope, river, residential point etc. Thirdly, the author finding the suitable place is overlain with slope , river, soil erosion and residential point to decide where trees need to be planted and where grass need to be planted. At the same time, the order of converting the land for forest and the distribution of economic forest and the forest-grassland pattern are discussed. Finally, we got the best model of returning cropland to forestry (grass) in Pengyang.The results show: (1) RS is a fast and effective method for Monitoring Dynamic Change of returning cropland to forestry (grass). During this period, the cultivated area of Pengyang reduced by 20688hm , and wasteland afforest 29641hm~2, the project of returning cropland to forestry (grass) is in good state of development. (2) GIS technology provides valid methods and basis to realize the automatization and standardization of returning cropland to forestry (grass). It shows that the model of returning cropland to forestry (grass) is very useful .It provides us a successful example for returning cropland to forestry (grass) in Ningxia.