转换灌溉方式对农户种植决策和经济的影响——以河北省张北县为例

国内外研究表明节水灌溉技术具有田块尺度上的节水效益和对作物的增产效果。但从社会-经济-生态复合系统的角度，灌溉方式的转变是否会改变农户的种植决策和农业生产行为仍有待深入研究。本文以河北省张北县为例，通过实地调研建立了柯布-道格拉斯生产函数等模型，研究了转换灌溉方式对农户种植决策和福利的影响。结果发现，高效率的灌溉方式可以使旱作作物、低耗水作物和普通耗水作物的水分生产力提高25.0%~347.7%；但同时也促使了研究区域88.9%的农户种植用水强度更大、收益更高的经济作物，以期获得投资的回报；灌溉方式改变会影响农业生产的投入和产出，高效率的灌溉方式会增加灌溉设施建设成本（6.6%~16.2%），增加农药投入（2~4倍）、减少劳动力投入（20.6%~59.3%）。研究结果证明转换灌溉方式后，农户作为农业生产的基本单元，在追求利润最大化的动机驱动下，会改变其种植决策和农业生产行为，从而改变农户的经济效益。本文的研究结果可为进一步深入分析节水灌溉对区域农业生产的用水影响提供科学依据。

Effect of irrigation method on farmers' planting decision and the economy: A case in Zhangbei County, Hebei Province

Owing to drought and water shortage in North China, water-saving irrigation is considered an effective measure to reduce agricultural water consumption. Domestic and foreign studies have shown the effect of water-saving irrigation technology on water saving and crop yield increase at the field scale. However, from the perspective of the socio-economic-ecological compound system, the shift of irrigation methods can change the farmers'' planting decision and agricultural production behavior, which has a complex effect on the regional agricultural water use. Taking Zhangbei County of Hebei Province as an example, through field investigation and model simulation, we analyzed the effect of irrigation methods conversion on farmers'' planting decisions and welfare. It was found that high-efficiency irrigation methods improved water productivity of crops by 25.0%-347.7%. Under the same input of other factors and the same amount of water resources, higher yields and benefits were obtained through the adoption of high-efficiency irrigation methods. In the case of scarce water resources, the same output was achieved with relatively less water resources. Secondly, when farmers adopted high-efficiency irrigation practices, 88.9% of the local farmers grew more water intensive cash crops with higher yields to obtain higher investment returns. At the same time, farmers also tended to shift from minimizing material inputs to maximizing profits. For crops with lower yields, compensating the cost of irrigation facilities with the benefits of using high-efficiency irrigation methods was often difficult, and farmers were less motivated to change irrigation practices. Thirdly, changes in irrigation methods affected the input and output of agricultural production, increased the construction cost of irrigation facilities by 6.6%-16.2%, the input of pesticides by 2-4 times, and decreased labor input by 20.6%-59.3%. With the economic situation of yearly increase in labor costs, the reduction in labor input owing to drip irrigation and the increase in labor productivity were likely to be the primary reasons why farmers were willing to choose high-efficiency irrigation methods. The results of the study explained why farmers choose to change the irrigation method, how the individual planting decisions of farmers change, and the economic effect on farmers after the transition. As the transformation of individual farmers'' irrigation methods and their planting decisions had a direct effect on the water use of regional agricultural production, the results of this study provided a scientific basis for further analysis of the effect of water-saving irrigation on regional agricultural production.