Study on Grassland Degradation at the Middle and Lower Reaches of Tarim River by Monitoring Land Use

Based on GIS technology and TM images (during 1990～2000),the dynamic change of land use pattern at the middle and lower reaches of Tarim river is shown in this paper.The results indicate that the proportion of high coverage and middle coverage grassland is decreasing in this area,and the proportion lower coverage grassland increases at the expense of the natural Populus euphratica and the cultivated land wasted.At the same time,the natural grassland is disappearing and degrading toward desert at the lower reaches of Tarim river.In a word,the whole tendency of degradation is desertification.Some suggestions are discussed in this paper for restoring the degraded natural grassland in this region.