Monitoring sandy desertification of Minqin oasis, northwest China by remote sensing and GIS

Sandy desertification of Minqin oasis was monitored by the combined use of remote sensing and GIS. After interactive interpretation of the landsat TM (1986) and ETM+ (2000) images, sandy desertification map and land-use map were compiled and analyzed by GIS softwares, Arc/View and ArcGIS. Results show that: (1) in 2000, the total sandy desertification land area was about 4087.5649 km², in which the area of the slightly sandy desertification land occupied 1.54%, the moderately land 6.60%, the severely land 14.78% and the very severely land 77.08%; (2) three sandy desertification types were identified: grassland desertification, farmland desertification and dune reactive or encroach which occupied about 1784.9233 km², 178.9948 km² and 2123.6468 km² in area respectively; (3) from 1986 to 2000, the most important change was the increase of farmland, mainly converted from grassland, salinized land, sand land and woodland. But, all these reclaiming actions were at the risk of sandy desertification, especially, the rapid development of sand land reclamation has badly damaged the periphery environment of the oasis and accelerated the sandy desertification. Some constructive countermeasures, for the ecological protection and the ecological refugee settlement of Minqin oasis, are proposed in the paper.