农业节水的核心问题是提高水分利用率和水分利用效率。重点阐述了提高田间水平的水分利用率和水分利用效率的有关理论。特别从叶片水平、群体水平、产量水平 3个不同层次详细论述了作物水分利用效率与环境因子关系的理论 ,以及从理论出发得出的提高不同层次作物水分利用效率的可能途径。强调农业节水的科学基础是一个涉及多学科的综合理论体系 ,农业节水的措施也应该是建立在这一综合理论体系上的综合技术体系。最后 ,对为加强农业节水科学基础而应进一步强化的研究方向提出了几点建议 The key problem of water saving in agriculture is to improve water use efficiency and water use efficiency. It mainly elaborates the related theory of raising water use efficiency and water use efficiency at field level. In particular, the theories of crop water use efficiency and environmental factors are discussed in detail at three different levels: leaf level, population level and yield level, and the possible ways to improve the water use efficiency of different levels from the theory. Emphasizing that the scientific basis of water saving in agriculture is a multidisciplinary and comprehensive theoretical system, and the measure of water saving in agriculture should also be an integrated technical system based on this comprehensive theoretical system. Finally, some suggestions are put forward for further strengthening the scientific foundation of agricultural water saving