Changes of Desertification from 1985 to 2000 in South of Korqin Sandy Land

Based on the desertification data obtaining from TM image from 1985 to 2000, with the software of ARC/INFO and Access, desertification land composition and its distribution are studied, and also, changes character in area, degree and spatial from 1985 to 2000 are analyzed. The conclusions as follows: The desertification land area in the south of Korqin sandy land is large with the ratio between 44% and 50%. The main desertification type is moderate. With the effecting of topography and the main wind directions, there are some features in the distribution of desertification land. The serious and severe desertification land mainly distributed in the patches in the west region, several desertification degrees interlaced in the east with the extension from east to west, and the north region is the region with the light and moderate desertification lands. From 1985, the area of desertification land enlarged and the degree of it mitigated. The main degrees of desertification land of stable are the severe and moderate, the main degrees of desertification land of upgrading are light upgrading and middle upgrading, and on the other hand, the main degree of desertification land of degrading is light degrading. The changing trend among desertification degrees is that the potential desertification land developed into light and moderate desertification land, and the serious and severe developed into moderate desertification land, which with great relationship to the people's attitude to all kinds of desertification degrees and the selection of controlling area. The desertification land of light degree and the potential desertification land should be give much more attention in order to avoiding its upgrading and the new desertification land coming into being.