中国农产品虚拟水与资源环境经济要素的时空匹配分析

Analysis on the Spatial-Temporal Matching of Crops Virtual Water Versus Resources-Environment-Economy Factors in China

虚拟水是当今水科学的研究热点,被认为是解决水资源与粮食安全的重要策略。本文在计算中国各地区农产品虚拟水总量的基础上,计算出1996年—2006年中国各地区农产品虚拟水与水资源、耕地、人口、化肥施用和水土流失治理以及GDP等要素的基尼系数,对中国农产品虚拟水与资源环境经济要素匹配的时间变化规律进行研究。计算结果表明:中国农产品虚拟水与水资源、化肥施用近10年来地域匹配差异呈振荡特征,虚拟水与水资源匹配程度最差;中国农产品虚拟水与耕地、水土流失治理地域差异性在缓慢减小,匹配程度在变好;中国农产品虚拟水与人口、GDP地域差异性在缓慢扩大,匹配程度在下降。之后对上述规律进行了分析。在空间上,将全国分为八大区域,以2006年为例,通过计算各区农产品虚拟水-资源环境经济要素不平衡指数,分析各地区农产品虚拟水与资源环境经济要素在空间上的匹配规律,找出各类影响外部不公平性的主要地区。同时,本文研究结论表明:虚拟水战略有其现实局限性,对其作用应该有客观的评价,对其适用性应该有清醒的认识。

For a water-scare region it would be a correct strategy to produce and export products with relatively low virtual water content and to import products having higher virtual water content. Virtual water has become a focus of water sciences, and has been regarded as a major countermeasure to address the issues of food security and water security. In the present work, on the base of the calculation of the total quantity of virtual water of main crops, the authors computed the Gini coefficient of crops virtual water versus six resources-environment-economy factors, i.e., population, cultivated land, water resources, consumption of chemical fertilizer, management of soil-water erosion and GDP. In addition, the temporal distribution of differences in crops virtual water versus the six factors during the period 1996 to 2006 in China was examined in detail. Results indicated that the Gini coefficients of crops virtual water versus water resources and chemical fertilizer were oscillating, showing a least matching degree for crops virtual water versus water resources. It was also found that the coefficients of crops virtual water versus cultivated land and management of soil-water erosion progressively decreased with years, showing a matching degree becoming better and better. The Gini coefficients of crops virtual versus population and GDP were found to slowly increase, showing a matching degree becoming worse with time. Regarding spatial distribution characteristics, the authors divided China into eight studied regions, and calculated the imbalance index of crops virtual water versus the six resources-environment-economy factors for the partitioned regions. The spatial matching characteristics of crops virtual water versus the six resources-environment-economy factors in year 2006 were analyzed, indicating that the main regions affected the outer parts. The outside fairness of the virtual water system for China＇s agricultural products was found to be relatively low, suggesting that the Huang-huai-hai and Northeast regions were the most prominent areas. In summary, the findings of the study would assist policy makers in formulating reasonable agricultural policies to guarantee national food security and meanwhile to account for sustainable development of resources, environment and economy. Water resources availability does not affect differences in virtual water at all whereas regional cultivated land plays a crucial role in virtual water. To this end, the virtual water strategy has certain limitations, which accounts for virtual water trades only in the aspect of the levels of water resources abundance. In this case, we should formulate and evaluate the virtual water strategy with caution and consider the applicability of the concept of virtual water.