农业水价综合改革对干旱区节水和农户收入的影响研究

Agricultural water price has been lower than the cost of water supply for a long period of time is considered to be the most important cause of waste of agricultural water resources. In the comprehensive reform of agricultural water price, it is proposed that the economic leverage of water price should be brought into full play, and should establish a reasonable water price formation mechanism to promote water conservation, water use planning, and the improvement of water resources utilization efficiency and efficiency. However, it is still controversial whether the price lever can achieve the goal of saving water，and raising water price will increase the burden on peasants and affect farmers' food production decisions. Water price reform is crucial to the formation of water-saving agriculture, and it is related to the interests of farmers and food security. Taking Zhangye City in the arid region as an example, this study will construct a multi-objective linear optimization model over the irrigation districts level by combining the water resources model with the economic behavior model of farmers based on a large number of farmer field survey data，to discuss in depth on the policy effect of comprehensive reform of water price, reveal the essential relationship between water prices and water saving in agriculture, farmers’ income, and food production, portray the price curve of water demand, and research on the precision subsidies and incentive subsidies for water price, in order to provide empirical references for the formation mechanism of water price in arid regions.

灌溉水价长期低于供水成本，被认为是造成农业水资源过渡浪费的重要原因。农业综合水价改革提出要充分发挥水价的经济杠杆作用，通过建立合理的水价形成机制，促进节约用水、计划用水，促进水资源利用效率和效益的提高。但价格杠杆能否达到节水的目标争议颇大，同时提高水价会增加农民负担，影响农户生产决策。水价改革对于节水农业形成至关重要，关系农户利益及粮食安全。本研究拟以干旱区张掖市为例，通过大量农户实地调研，获取一手数据，将水资源模型嵌入农户经济行为模型中，构建灌区层面多目标线性优化模型，深入讨论干旱区水价综合改革的政策效果，揭示水价与农业用水、农户收入、粮食生产之间的本质关系，刻画干旱区用水需求价格曲线，提出适合干旱区的水价精准补贴和节水奖励机制，为建立健全干旱区水价形成机制提供科学参考。

建立健全合理反映供水成本、有利于节水和农田水利体制机制创新、与投融资体制相适应的农业水价形成机制，是我国农业水价综合改革的核心。水价综合改革对于节水农业形成至关重要，关系农户利益及粮食安全。该研究以西北干旱区黑河中游为例，系统梳理流域水价改革变迁历程，揭示干旱区农业水价形成机制，综合评估了水价改革节水效应及对农户收入、粮食安全产生的广泛影响。干旱区农业水价综合改革分步推进，当前先将农业水价提高到供水成本，然后再设计分类水价政策。研究发现：（1）当前水价改革不会对干旱区节水、种植结构调整及粮食安全产生重大影响。农户对于水价上涨的经济和心理承受能力较强，流域用水浪费现象仍然存在。其背后的真正机制在于干旱区水资源影子价格高（0.88-4.0元/m3左右），提高后的水价（0.182元/m3）虽覆盖70%供水成本。但远低于水资源经济市场价值（影子价格反映），综合考虑成本和收益，农户用水对于价格弹性小。（2）不同分类水价政策效应的影响机制存在较大差异。分作物水价政策有利于粮食安全保障，会促进耕地开垦。分季节水价政策节水作用不明显，会极大增加农户灌溉成本。超额累进水价政策是有效手段，可有效压缩超额水权部分用水量，促进节水。需要严格的水资源管理制度和精准计量设施为基础。（3）精准补贴和节水奖励加大财政压力，对于减轻农户负担作用微乎其微。不能弥补农户因灌溉水价上涨造成的结构调整损失，而且分解到单个农户、单个地块来说，金额极小，在当前非农收入在农户收入中占比不断提高背景下，属于“撒胡椒面”式补贴，无法有效激励农户实施节水。（4）高效节水灌溉技术可以提高用水效益，但并不能够降低整个区域农业用水量。在经济利益的驱动下，节约的用水会被农户用于开垦新的耕地，高效节水技术存在用水反弹。水价政策在抑制用水需求和耕地开垦方面作用有限，必须采取严格的耕地管控和水资源管理行政手段。