Key Laboratory of Agricultural Water Resources, Hebei Laboratory of Agricultural Water-saving, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang 050021, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Agricultural Water Resources, Hebei Laboratory of Agricultural Water-saving, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang 050021, China.
Sci Total Environ. 2018 Jun 1;626:11-21. doi: 10.1016/j.scitotenv.2018.01.071. Epub 2018 Jan 12.
While agriculture places the greatest demand on water resources, increasing agricultural production is worsening a global water shortage. Reducing the cultivation of water-consuming crops may be the most effective way to reduce agricultural water use. However, when also taking food demand into consideration, sustaining the balance between regional water and food securities is a growing challenge. This paper addresses this task for regions where water is unsustainable for food production (Beijing-Tianjin-Hebei Region for example) by: (i) assessing the different effects of wheat and maize on water use; (ii) analyzing virtual water and virtual land flows associated with food imports and exports between Beijing-Tianjin-Hebei and elsewhere in China; (iii) identifying sub-regions where grain is produced using scarce water resources but exported to other regions; and (iv) analyzing the potentiality for mitigating water shortage via Land-Water-Food Nexus. In the Beijing-Tianjin-Hebei Region, the study reveals that 29.76 bn m of virtual water (10.81 bn m of blue virtual water) are used by wheat and maize production and 8.77 bn m of virtual water used in nearly 2 million ha of cropland to overproduce 12 million ton of maize for external food consumption. As an importing-based sub-region with high population density, Beijing & Tianjin imported mostly grain (wheat and maize) from Shandong Province. Then, Hebei Province, as an exporting-based sub-region with severe water shortage, overproduced too much grain for other regions, which aggravated the water crisis. To achieve an integrated and sustainable development of the Beijing-Tianjin-Hebei Region, Hebei Province should stop undertaking the breadbasket role for Beijing & Tianjin and pay more attention to groundwater depletion. The analysis of the Land-Water-Food Nexus indicates how shifts in cultivated crops can potentially solve the overuse of water resources without adverse effects on food supply. It also provides meaningful information to support policy decisions about regional cropping strategies.
虽然农业对水资源的需求最大，但农业生产的增加正在加剧全球水资源短缺。减少耗水作物的种植可能是减少农业用水的最有效途径。然而，当考虑到粮食需求时，在区域水资源和粮食安全之间保持平衡是一个日益严峻的挑战。本文针对那些水资源无法维持粮食生产的地区（如京津冀地区），通过以下方法来解决这一问题：（一）评估小麦和玉米对水资源利用的不同影响；（二）分析京津冀地区与中国其他地区之间粮食进出口所涉及的虚拟水和虚拟土地流动；（三）确定那些使用稀缺水资源生产粮食但却将其出口到其他地区的次区域；（四）通过土地-水-粮食关系分析缓解水资源短缺的潜力。研究结果表明，在京津冀地区，小麦和玉米的生产消耗了 297.6 亿立方米的虚拟水（其中 108.1 亿立方米为蓝水），297.6 亿立方米的虚拟水用于近 200 万公顷农田的生产，以生产 1200 万吨用于外部粮食消费的玉米。作为一个以进口为基础、人口密度高的次区域，北京和天津主要从山东省进口粮食（小麦和玉米）。然后，河北省作为一个以出口为基础、水资源严重短缺的次区域，为其他地区生产了过多的粮食，加剧了水资源危机。为实现京津冀地区的综合可持续发展，河北省应停止为北京和天津承担粮食供应基地的角色，更加关注地下水的枯竭问题。土地-水-粮食关系的分析表明，通过调整种植作物，可以在不影响粮食供应的情况下，潜在地解决水资源过度利用的问题。它还为支持关于区域种植策略的政策决策提供了有意义的信息。
