中国粮食作物灌溉用水效率时空特征及驱动因素——以稻谷、小麦、玉米为例

在中国粮食生产与水资源分布日益不平衡的背景下,提高灌溉用水效率是保障粮食安全和水资源安全的战略需要。本文运用投入导向型DEA和面板Tobit模型,探究了2008—2017年中国稻谷、小麦和玉米的灌溉用水效率的时空特征和驱动因素差异。结果表明：中国稻谷、小麦和玉米灌溉用水效率均有较高提升空间,其中稻谷和小麦在研究期内呈现波动上升趋势,而玉米则呈现倒“U”型趋势。空间分布方面,玉米各主产区的灌溉用水效率基本超过全国平均水平,其主要问题为效率值波动较大;而稻谷和小麦主产区中,华南双季稻区、北部冬麦区和长江中下游冬麦区的灌溉用水效率及增长幅度较低。进一步的驱动因素分析表明,资源环境的变化更易驱动玉米灌溉用水效率;现有节水灌溉条件下农田水利设施对不同粮食作物灌溉用水效率的驱动方向和作用程度差异较大;经济社会发展对3种粮食作物灌溉用水效率均有较大驱动力。基于以上研究,本文对因地制宜制定实施粮食水资源管理政策提出了针对性建议。

Driving factors and spatiotemporal differentiation of irrigation water use efficiency in China

Under the background of increasing imbalance between grain production and water resource distribution in China, it is imperative to improve irrigation water use efficiency to guarantee food security and water resource security.Using input-oriented data envelopment analysis (DEA) and panel Tobit model, this study explored the spatial and temporal characteristics and driving factors of irrigation water use efficiency of China’s rice, wheat, and corn in 2008-2017. The results show that irrigation water use efficiency of rice, wheat, and corn in China had a largeroom for improvement. Among these crops, the water use efficiency of rice and wheat showed an upward trend during the study period, while corn showed an inverted “U” trend. In terms of spatial distribution, the irrigation water use efficiency of the main production areas of corn was basically higher than the national average level, butthe efficiency value fluctuated greatly. Among the main production areas of rice and wheat, the irrigation water use efficiency values and growth rates ofdouble cropping rice areas in South China, winter wheat areasin North China, and winter wheat areasin the middle and lower Yangtze River Basin were relatively low. Further driving factor analysis showed that the change of resourcesand environment was more likely to affect the irrigation water use efficiency of corn; under the existing water-saving irrigation conditions, farmland water conservancy works had differentdriving effects on irrigation water use efficiency of the different types of graincrops; economic and social developmentisa great driving force for the irrigation water use efficiency of the three graincrops. Based on the above conclusion, this article put forward some targeted suggestions for formulating and implementing agriculturalwater management policies based on local conditions.