摘 要 ：对科尔沁沙地近50年来沙漠化土地面积、水资源可利用性、土地利用与草地植物生产力的变化进行了分析.结果发现：科尔沁沙地的土地沙漠化在经历了20世纪50—80年代中期的快速发展之后，80年代后期发生了逆转.在过去的50年中，西辽河径流量持续减小，1999年在西辽河中游的内蒙古自治区通辽市段断流;近20年来，位于科尔沁沙地腹地的西湖水位下降近10 m, 2001年干涸.科尔沁沙地草场的地上生物量由1937年的520 g·m-2下降到2005年的197 g·m-2.产生这种结果的主要原因是土地利用方式的变化，即基于灌溉的沙漠化治理规模的扩大和灌溉农田面积的增加,导致用水量增加.这也是科尔沁沙地实现土地沙漠化持续逆转面临的严峻挑战.
Abstract:Analyses of the changes in desertified land area, water resource a vailability, land use, and plant productivity in Horqin Sandy Land in recent 50 years showed that from 1950 to the late 1980s, the land desertification in Horqin Sa ndy Land had a rapid expansion, but reversed since then. The annual runoff of Xi liaohe River decreased consistently, and in 1999, the middle reach at Tongliao s ection was dried up. In recent 20 years, the water table of Xihu Lake was decrea sed by about 10 m, and dried up in 2001. The above-ground biomass of grasslands decreased from 520 g·m-2 in 1937 to 197 g·m-2 in 2005. The main c ause of these results was the change of land use pattern, i.e., the overuse of w ater resources for re-vegetation or cropland irrigation. Water resources reduct ion was the major challenge to the desertification reversion in Horqin Sandy Lan d.