[目的]共和盆地位于青藏高原的半干旱区, 属于典型的高寒沙地, 是青海省土地荒漠化最严重的区域之一.乌柳是当地退化草地恢复的主要树种, 乌柳林的稳定性是其可持续管理的关键.研究夏季乌柳林的水分来源以分析它们在半干旱区能否维持稳定性.[方法]利用稳定氢、氧同位素技术研究了夏季4个林龄乌柳林的水分来源, 比较乌柳林的木质部水分与各潜在水源的稳定氢、氧同位素值, 确定7月乌柳林主要利用的水源.[结果]不同林龄乌柳林可利用不同深度的土壤水或地下水.其中, 2年生乌柳林主要利用地表下25 cm的土壤水, 占总水源的75.5％;10年生乌柳林主要利用地表下25～75 cm的土壤水和地下水, 占总水源的73.9％;20年生乌柳林主要利用地表下50～75 cm的土壤水和地下水, 占总水源的67.7％;30年生乌柳林主要利用地表下25 cm的土壤水和地下水, 占总水源的69.6％.随着林龄的增加 (从10 a到30 a), 乌柳林对地下水的依赖性逐渐增强.[结论]乌柳林通过调整水分利用策略来适应共和盆地的半干旱气候.利用稳定的深层土壤水和地下水有助于长期维持乌柳林稳定性, 建议将乌柳作为高寒沙地和其他半干旱地区退化植被恢复的主要树种推广.“,”[Objective]The Gonghe Basin is located in a semiarid zone of the Qinghai-Tibet Plateau, which is a typical alpine sandy region.It is one of the most severely desertified areas of Qinghai Province.The Salix cheilophila is mainly used in the restoration of degraded grassland in the interdune areas of the Gonghe Basin.The stability of S.cheilophila plantations is dependent on sustainable management.Our objective was to evaluate whether the long-term stability of S.cheilophila plantations could be maintained in the semiarid zone by analyzing their water sources during summer.[Method]The water sources of different S.cheilophila plantations of different ages were studied through stable hydrogen and oxygen isotope techniques.The stable hydrogen and oxygen isotope ratios of S.cheilophila xylem water were compared with those of soil water at different depths (25, 50, 75, 100, 150, 200 cm) and ground water to determine the main water source for S.cheilophila plantations of different ages in July.[Result]The S.cheilophila plantations of different ages mostly used different depths of soil water or ground water.At two years of age, the S.cheilophila plantations mainly used25 cm soil water, which accounted for 75.5％of its total water source.At ten years of age, the S.cheilophila plantation mainly used 25-75 cm soil water and ground water, which accounted 73.9％to its total water source.At twenty years of age, the S.cheilophila plantation mainly used 50-75 cm soil water and ground water, which accounted 67.7％of its total water source.At thirty years of age, the S.cheilophila plantation mainly used 25 cm soil water and ground water, which accounted 69.6％to its total water source, respectively.With the increase in plantation age, the dependence of the S.cheilophila plantations on ground water increased, particularly from 10 years to 30 years of age.[Conclusion]The water use strategy of the S.cheilophila plantations adjusted to adapt to the semiarid climate.The long-term stability of the plantations was maintained by use of stable ground water or deep soil water in the Gonghe Basin.It is suggested that the S.cheilophila could be widely used in the restoration of degraded alpine sandy regions and other semiarid zone.