Land use history and status of land desertification in the Heihe River basin

An analysis, over historical times, of the influence of natural factors such as climate, geological activity, existing landforms, and the activity of aeolian sands on the desertification of oases and other lands in the Heihe River basin of northwestern China revealed that desertification occurred more or less quickly according to whether the prevailing climate was cold or warm, respectively. In the 1990s, the area of desertified lands in the lower reaches of the Heihe River (Ejin region) was 29.1% greater than in the mid 1980s. However, the rate of desertification in the middle reaches of the Heihe River basin was relatively slower, only 9.4% from 1949 to 1990 (or 0.27% per year). Since 1990, the rate of desertification has been stable. By 2000, the total area of land desertification in the mid to lower reaches of the Heihe River basin was 13,508.4 km2, or 11.8% of the region monitored. Of the total land desertification area, the regions of Linze, Gaotai, Sunan, Jiuquan, Jia Yuguan, and Jinta accounted for 1.70, 1.71, 1.43, 0.85, 0.28, and 9.39%, respectively, whereas the Ejin region’s 11,434.64 km2 accounted for 84.65%, indicating that land desertification in the lower Heihe River basin was particularly severe. The causes responsible for the occurrence and development of land desertification in the Heihe River basin were analyzed.