中文摘要：

节水灌溉技术采用率低下已成为制约西北干旱地区农村经济可持续发展的关键。理论研究发现,信贷约束对具有资本密集型特质的节水灌溉技术采用产生影响,而社会资本对信贷约束具有一定的缓解作用。基于此,本文使用甘肃张掖483户农户调研数据,首先,将通过意愿调查法获得的农户金额约束、利率约束和期限约束数据资料表征农户信贷约束程度,并应用探索性因子分析法构建社会资本指数;其次,运用Probit模型实证分析信贷约束、社会资本对节水灌溉技术采用的影响;再次,分别引入社会资本与金额、利率和期限约束的交互项,检验社会资本对信贷约束的缓解效应;最后,通过稳健性检验与边际效应分析对实证结果和影响程度进行检验。结果发现：（1）信贷约束的三个维度——金额约束、利率约束和期限约束分别对节水灌溉技术采用行为具有显著的抑制作用,而社会资本对农户采用节水灌溉技术具有积极促进作用。金额约束每增加1万元,节水灌溉技术采用概率降低1.96%;利率约束每上升1%,采用概率下降0.77%;期限约束每延长1年,采用概率下降2.39%;农户社会资本每提高一个档次,采用概率提升21.04%。（2）社会资本通过民间借贷等形式,对技术采用过程中的金额与利率约束有显著的缓冲功能;受民间借贷期限不稳定等因素的影响,社会资本对期限约束的缓解效应并不明显。（3）户主年龄、受教育程度、所在村庄与乡镇的距离以及是否接受过技术推广服务均对节水灌溉技术采用行为有显著影响。

英文摘要：

Low rate of water-saving irrigation technology adoption has become the key issue to the sustainable development of the arid area in northwest China. By theoretical studies, we find that credit constraints may have some impacts on the adoption of water-saving irrigation technology which has the qualities of capital intensive technology, and social capital can ease credit constraint. Based on the survey of 483 farmer households in Zhangye of Gansu Province, firstly, tihs paper gives three index to credit constraints by contingent valuation method and buihs social capital index by factor analysis method ; secondly, we analyse the influence of credit constraints and social capital on the adoption of water-saving irrigation technology by Probit model ; thirdly, we add the interaction of social capital and amount, interest rate and term constraints to test the mitigation effect of social capital on credit constraints in the decision making process ; lastly, we prove the robustness of models and measure the marginal effect. The results shows that ： （1） credit constraints come from amount, interest rate and time limit the adoption of water saving irrigation technology significantly, while social capital can promote the adoption effectively. When amount constraint adds 10 000 yuan, interest rate raises 1% and time constraint extends 1 year, the probability of adoption drops 1.96% , 0.77% and 2. 39% respectively. When social capital improves a grade, the probability raises 1.96%. （2）Social capital buffers the amount and rate constraints through the private lending. However, it can＇t buffer time constraint, because the time of private loan is not stable. （3）Householders＇ age, education level, the distance of village to town, and whether to accept a technical extension services influence the adoption of water-saving irrigation technology significantly.