针对内陆干旱草原区水资源日益短缺，开展区内草地生态需水的研究，可为区域草原生态建设规划和水资源配置提供参考。选取肃南裕固族自治县作为内陆干旱草原区的典型代表区，采用联合国粮农组织（FAO）推荐的干旱区受破坏非完全覆盖的天然植被生态需水计算方法，研究了区域植被生长季（3月－10月）参考作物蒸散发量随时间的趋势性变化及其空间分布特征，分析了不同草地类型生态需水定额和有效降雨量的特征关系，并通过对各乡镇天然草地生态需水量与生态缺水量计算发现：肃南县在不同水文年均存在一定的生态缺水现象，明花乡表现最为严重，生态环境脆弱，应积极改变牧区发展模式，保护草地生态系统的和谐与稳定。

Estimation of ecological water requirement for natural grassland can provide reference for regional grassland ecological construction planning and water resources allocation,in order to solve the regional water shortage problems.The methods of estimating ecological water requirement for non-pristine and non-full coverage natural vegetation were proposed by FAO.The Sunan Yugu Autonomous County in the typical western pastoral areas was chosen as a case study in this paper.The reference crop evapotranspiration of vegetation in the regional and its trend in the crop growing season from March to October were computed.The characteristics of the relationship between effective precipitation and ecological water requirement quota for different grassland types were also investigated.It is found that the Sunan County had a shortage of ecological water requirement at all different hydrological years,while comparing demands and supply.The situation is more serious in the Minghua,implying its fragile ecological environment.The regional development planning should be adjusted to ensure the harmony and stability of grassland ecosystems.

国家重点研发计划（2016YFC0400301）