西北干旱区作物灌溉技术效率及影响因素

水资源短缺是制约西北干旱区可持续发展的硬约束,提高作物灌溉技术效率、压缩农业灌溉用水是缓解水资源供需矛盾的可能途径之一。基于2014年张掖市农户调研数据,采用DEA-Tobit模型,分析了黑河流域中段不同类型灌区作物灌溉技术效率及其影响因素。结果表明：（1）典型灌区主要作物灌溉技术效率均存在改进空间,节水潜力较大。在其他投入保持不变的情况下,如果典型灌区主要作物灌溉技术效率达到目前的最高水平,平原灌区生产同样产量的制种玉米和大田玉米,灌溉用水可分别减少34.47%和38.15%;北部荒漠灌区生产同样产量的棉花、制种西瓜和玉米套小麦,灌溉用水可分别减少48.42%、34.82%和22.99%;沿山灌区生产同样产量的小麦、马铃薯、大麦和大田玉米,灌溉用水可分别减少14.48%、30.75%、25.50%和35.96%。（2）不同灌区之间作物灌溉技术效率的变异系数与作物种植面积占比呈负向关系,同一灌区内部种植相同作物的农户生产管理水平存在明显差异。（3）农地细碎化程度和农户耕地面积扩大会降低作物灌溉技术效率,改善耕地质量能提高北部荒漠灌区作物灌溉技术效率,增加井水灌溉会提高平原灌区大田玉米和沿山灌区作物灌溉技术效率,灌溉次数与多数作物灌溉技术效率呈“倒U型”关系,而农户耕作需求及其对风险态度的影响需结合具体情况进行判断。合理确定种植规模、加快农地空间优化,因地制宜地改善耕地质量,完善水利设施、合理使用井灌、增强河水灌溉放水的灵活性,是提升黑河流域作物灌溉技术效率的主要途径。

Technical efficiency of crop irrigation and its determinants in the arid areas of Northwest China

The shortage of water resources has become a hard constraint to the sustainable development of the arid areas of Northwest China. Increasing the technical efficiency of crop irrigation (TECI) and reducing agricultural irrigation water use may be one of the possible ways to ease the contradiction between water supply and demand. Based on the survey data of farmers in Zhangye city in 2014, this paper uses the DEA-Tobit model to analyze the TECI and its determinants in different types of irrigation zones in the middle reaches of the Heihe River Basin. The results show that there is a certain improvement space of TECI of main crops in the typical irrigation zones. With the other inputs unchanged, if the TECI reaches the current highest level in different types of irrigation zones, in order to produce the same amount of the seed maize and maize, the irrigation water can be reduced by 34.47% and 38.15% in the plain irrigation zone; in order to produce the same amount of the cotton, seed watermelon and maize-wheat (inter-corn), the irrigation water can be reduced by 48.42%, 34.82% and 22.99% in the northern desert irrigation zone; in order to produce the same amount of the wheat, potato, barley and maize, the irrigation water can be reduced by 14.48%, 30.75%, 25.50% and 35.96% in the mountain irrigation zone. In addition, the coefficient of variation of the TECI in different irrigation zones is negatively related to the proportion of cropland area, and there is a significant difference in the production management level of farmers who grow the same crop in the same irrigation zone. What's more, the fragmentation degree of cultivated land and the expansion of cultivated area have negative effects on the TECI in different irrigation zones, improving the quality of cultivated land has a significant positive effect on main crops in the northern desert irrigation zone. Increasing well water irrigation has a positive effect on crops such as maize in plain irrigation zone and wheat, potato, maize in mountain irrigation zone, and there is an inverted U-shaped relationship between irrigation frequency and the TECI. However, the influence of farmers' demand for cultivation and the attitude towards risk need to be judged based on specific conditions. Therefore, determining the production scale, accelerating the optimization and reorganization of cultivated land and improving the quality of cultivated land, rationally guiding the use of well irrigation, and enhancing the water conservancy facility and the flexibility of river water irrigation are the main ways to improve the TECI in the Heihe River Basin.