水资源安全视角下我国粮油虚拟水贸易实证研究

[目的]通过测算我国粮油虚拟水进出口量,估算粮油虚拟水贸易对农业用水的贡献率,以期为我国实施农产品虚拟水贸易战略缓解农业用水短缺问题提供有益借鉴。[方法]文章利用标准彭曼公式估算2001—2017年我国粮油单位质量虚拟水含量,进而计算出2001—2017年我国粮油虚拟水进出口量,进一步计算我国粮油虚拟水贸易对农业用水的贡献率。[结果](1)我国粮油单位质量虚拟水平均含量由高到低依次为棉籽、大豆、油菜籽、花生、大米、小麦和玉米;(2) 2001—2017年我国粮油虚拟水贸易一直处于净进口状态,并且净进口量整体呈增长趋势,2001—2017年我国粮油虚拟水净进口量累计达2.216万亿m3,相当于节约了同等数量粮油生产用水量;(3)我国油料虚拟水净进口量远远高于粮食虚拟水净进口量,大豆和油菜籽是虚拟水净进口最多的油料,并且其进口市场集中度很高;(4) 2001—2017年我国粮油虚拟水贸易对农业用水的贡献率不断提高,由8%增至40%。[结论]虚拟水贸易大大节约了我国农业用水量,在一定程度上缓解了我国农业用水短缺问题,为我国节约水资源和实施水资源可持续发展战略提供了新的发展思路。

EMPIRICAL STUDY ON CHINA'S GRAIN AND OIL VIRTUAL WATER TRADE FROM THE PERSPECTIVE OF WATER RESOURCES SECURITY

By measuring the import and export of China''s grain and oil virtual water, the present study estimates the contribution rate of grain and oil virtual water trade to agricultural water consumption, which could provide significant implications for the implementation of the agricultural product virtual water trade strategy in alleviating agricultural water shortage in China. This study employed the standard Penman formula to calculate the virtual water content of China''s grain and oil per unit mass from 2001 to 2017. Based on these estimates, this study then calculated the import and export volume of grain and oil virtual water and the contribution rate of grain and oil virtual water trade to agricultural water consumption. The results showed that the virtual level per unit mass of China''s grain and oil from high to low was in the order: cottonseed, soybean, rapeseed, peanut, rice, wheat, and corn. From 2001 to 2017, China''s grain and oil virtual water trade had been in a state of net import which was generally increasing. During the same period, the volume of China''s grain and oil virtual water net import sumed up to 2.216 trillion m³, which was equivalent to the same amount of water for grain and oil production had been saved. The net import of virtual water for oilseed was much higher than the net import of virtual water for grain in China. In particular, the volume of net import of virtual water of soybean and rapeseed tended to be the largest among the selected oilseeds. Meanwhile, import markets of soybean and rapeseed were highly concentrated. The contribution rate of China''s grain and oil virtual water trade to agricultural water consumption increased from 8% in 2001 to 40% in 2017. It is concluded that the virtual water trade has a profound impact on the reduction of China''s agricultural water consumption, which could alleviate the shortage of agricultural water significantly. The finding of the present study provides significant implications for China to save water resource and implement sustainable water development strategy.