[Temporal and spatial variation of land degradation in alluvial oasis at northern slope of Tianshan Mountain].

Taking the Fubei Farm, a farming oasis of Sangong River watershed at the northern slope of Tianshan Mountain as study area, and by the methods of geostatistics, GIS and RS, this paper studied the temporal and spatial variation of land degradation in topsoil (0-20 cm) and its relationship with landscape structure. The results showed that in this oasis, human activity was the key factor resulting in the increase of landscape fragmentation and diversity. From 1983 to 2005, the land degradation area decreased by 26.69%, and the degradation degree was higher in the regions adjacent to desert than in those further inside the oasis. Gray desert soil was degraded much more seriously than saline soil and aquic soil. The regions of poor land quality had an alleviated degradation, with 65.38% of land area improved, while those of good land quality had an aggravated degradation, with 33.38% of land area degraded.