基于省际间粮食贸易的虚拟水综合效益分析

虚拟水概念丰富水资源的形态与内涵，其价值不仅表现在人口-粮食-贸易为纽带的虚拟水贸易上,还表现在其社会属性上。基于虚拟水的双重价值，结合全国粮食各地产消平衡数据,构建线性优化模型,估算我国粮食省际间贸易的虚拟水流动格局，从资源、经济、环境3方面出发分析虚拟水流动引发的综合效益。结果发现：我国粮食省际间贸易的虚拟水流动格局表现为北水南运的特点，同实体水的南水北调形成互补，水资源南北互通；资源效益而言，我国省际间粮食贸易的虚拟水流动格局在全国范围内共节约了152.96亿m3的水资源，占总的虚拟水流动量的15.79%，表面的水资源节约现象背后隐藏着缺水区输水给丰水区的反常现象以及广大富水地区水资源利用效率低下的严重问题；经济效益总体上是增加的，工业增加值为6.77万亿元。经济效益增加分布较为集中，经济效益减损分布较为分散，效益减损需要构建地区补偿机制；环境效益结果不佳，农作物绿水占用指数高的地区在透支当地农业生态绿水情况下大量输出虚拟水，将会对其陆地自然生态系统造成严重威胁并制约当地社会经济发展。根据结果得出政策启示，为水资源管理、区域发展及生态安全提供新思考：引入实体水与虚拟水结合的水资源管理方式；构建协调区域发展的虚拟水补偿机制；维持绿水与蓝水结构平衡的生态安全。 关键词： 省际间粮食贸易；虚拟水流动；资源效益；经济效益；环境效益

Comprehensive Benefits Analysis of Virtual Water Based on Inter Provincial Trade

The concept of virtual water is rich in the form and connotation of water resources, and Its value is reflected in, not only the virtual water trade taking population, grain and trade as a link, but also the social attributes. Based on the double value of virtual water, combined with the equilibrium data of national grain production and consuming, a linear optimization model was built to estimate the virtual water flow pattern of China's inter-provincial grain trade. Then the comprehensive benefit caused by virtual water flow was analyzed from the aspects of resources, economy and environment. The result shows that the virtual water flow of China's inter-provincial grain trade manifests the characteristics that the North water flows to the South. It is complementary to the South-to-North Water Diversion Project of physical water. That realize the interflow of water resources between north and south. In terms of resource efficiency, the virtual water flow pattern of inter-provincial grain trade in China has saved 15.296 billion cubic meters of water resources in the whole country, accounting for about 15.79％ of the total virtual water flow. What behind the surface water conservation is the anomalous phenomenon that water transfers from deficient area to sufficient area and that the serious problems of low utilization efficiency of water resources in the widespread water sufficient area. When it comes to economic benefits, the overall is increased, with industrial added value reaching 6.77 trillion yuan. The distribution of increased economic benefits on the contrary, the distribution of detracted economic benefits more dispersed, and the derogation of benefits requires the construction of regional compensation mechanism. Then we turn it to environment benefits, it is poor, and areas with high crop green water occupancy index output a large number of virtual water in the case of local agricultural ecological green water on overdraft. It will be a serious threat to the terrestrial natural ecosystems and restrict the development of local economy. According to the results, we can get some policy implications and provide new ideas for water resources management, regional development and ecological security. The policy implications include advocating water resource management method combined physical water with virtual water, constructing a virtual water compensation mechanism for coordinated regional development and maintaining ecological security with a balance between green water and blue water.