江苏省灌溉水变化驱动效应研究

Change in Irrigation Water Usage in Jiangsu Province and the Underlying Reason

【目的】确定经济系统中各要素对江苏省灌溉水变化的节水贡献。【方法】利用CROPWAT模型,量化了2002—2017年江苏省农作物灌溉水量,基于量化结果结合结构分解模型分析江苏省农作物用水的驱动效应,在江苏省投入产出表的框架下分析产业经济和贸易经济对降低灌溉用水量的可行性。【结果】生产结构和消费结构调整是近年来遏制灌溉水量攀升的关键驱动因素,2002—2017年分别削减192.9亿m3和106.2亿m3的灌溉用水量,江苏省通过发展食品制造业(生产经济占比从53%增加至64%)和国际贸易引入高耗水经济作物降低灌溉用水量。【结论】实现经济政策节水的核心在于农产品产业链(以食品制造业为主)的整体升级和高耗水农产品的对外转移,即通过提高农产品附加值和国际引入高耗水经济作物实现农业经济节水。

【Objective】Agriculture is the greatest water consumer.Reducing irrigation water usage is hence a priority in developing sustainable agriculture for many countries.While developing water-saving irrigation technologies is essential to achieving this goal,changing social activity and national and international trade can also play an important role.Taking Jiangsu province as an example,this paper analyzes the impact of non-technological factors on reducing irrigation water usage over the past 20 years.【Method】The CropWat model was used to calculate the change in water used for irrigation from 2002 to 2017 first.The results were then combined with a structural decomposition model to analyze the driving forces behind the change in irrigation water usage,from which we calculated the contribution of different factors to the changes.Based on an input-output table,we also analyzed the role of industrial and trade economies in reducing irrigation water.【Result】Change in agricultural production structures and food consumption was the key factors holding the increase in irrigation water usage over the past two decades,with the former reducing irrigation water usage by 19.29 billion m3 and the latter by 10.62 billion m3,during the studied period.The development of food industry combined with international trading by importing water-consuming cash crops over the past two decades also helped reduce the irrigation water usage.【Conclusion】The key to achieving water saving through changing economic policies is to restructure agricultural production chains and reducing cultivation of high-water-consuming crops.