总水势概念的定义、计算及应用条件  

Definition,calculation and application of total water potential

作　　者：景卫华[1] 贾忠华[2] 罗纨[1] 

机构地区：[1]西安理工大学水资源研究所,西安710048 [2]西安理工大学环境研究所,西安710048

出　　处：《农业工程学报》2008年第2期27-32,共6页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金资助项目(50209015);西安理工大学科技创新基金资助项目

摘　　要：SPAC系统理论中引入能量观点认为水分运移取决于其驱动力-水势差(即能量差)的大小和水流的阻力。但目前水势定义的本质是等温条件下摩尔吉布斯函数之差,并不能涵盖总能量。该文首先提出"总水势"的概念来表达水分的总能量,按照总能量观点对其进行定义;然后对构成总能量的每个分势进行了分析计算;最后,探讨了总水势的物理意义和限制条件,以了解实际应用中出现的一些误区。According to the theory of Soil-Plant-Atmosphere Continuum （SPAC）, water movement in the SPAC system depends on the driving force -water potential gradient （i.e. energy gradient） and flow resistance. However, the essence of present conception of water potential is the difference value of molar Gibbs function of water under isothermal condition, it does not cover the total energy of water in a considered system. A total water potential concept that expresses total energy of moisture in a given system was proposed, and methods for quantifying each component of the total water potential were presented. Finally, the physical meaning and the limitations of the total water potential were discussed to understand some mistake of total water potential application.

关 键 词：水势 总水势 吉布斯能势 摩尔吉布斯能函数 SPAC系统 

分 类 号：S152.72[农业科学—土壤学]