水-能-粮-土关联下长江经济带农业用水量时空特征及驱动因素分析

Study on Spatial-temporal Characteristics and Driving Factors of Agricultural Water Use in the Yangtze River Economic Zone Based on the Perspectives of Water-Energy-Food-Land Nexus

我国是水资源紧缺的国家,水资源时空分布与耕地、人口的分布也不相适应,农业发展因此受阻,研究农业用水量驱动因素对农业节水具有重要意义。选取农业经济占全国总量40%以上的长江经济带为研究对象,以水-能源-粮食-土地纽带关系为视角选取农业用水量的影响因素,运用对数平均迪氏指数分解法的方法将其时空演变驱动效应解析为人口规模效应、用水定额效应、土地利用效应、机械利用效应、人均机械动力效应以及农业就业结构效应,分析了影响农业用水量时空变化的主要驱动因素。结果表明:(1)人均机械动力效应和人口规模效应是农业用水增量的主要因素;(2)农业就业结构效应和机械利用效应是其减量的主要因素;(3)驱动效应在不同省市对农业用水量的影响具有异质性;(4)长江经济带农业用水量驱动效应存在时间和空间可相互转化的关联关系。因此,建议通过正反双向调节各驱动效应、分省市差异化制定节水政策以降低农业用水量,相邻省份优势互通,合作发展以缩小长江经济带区域内部农业用水量差异。

China is a country with scarce water resources,and the spatial-temporal distribution of water resources is not compatible with arable land and population.Agricultural development is thus hindered,it is important to study the drivers of agricultural water use to save water.This study selected the Yangtze River Economic Zone as the research object,the agricultural economy of which accounts for more than 40%of the national total,and selected the influencing factors of agricultural water consumption against the perspective of water-energy-food-land nexus.The LMDI method was used to analyze its spatial-temporal evolution and the driving effects related to population scale effect,irrigation quota effect,land use effect,machinery use effect,per capita mechanical power effect and agricultural employment structure effect.The results indicated that:(1)The per capita mechanical power effect and the population size effect are the main factors for the incremental water use in agriculture;(2)The agricultural employment structure effect and the machinery use effect are the main factors in the reduction of water use;(3)The driving effect is heterogeneous across provinces and cities in terms of its impact on agricultural water consumption;(4)There is a temporally and spatially interchangeable correlation between the driving effects of agricultural water use in the Yangtze River Economic Zone.Therefore,it is recommended to reduce agricultural water consumption by regulating each driver effect in positive and negative mutual directions and differentiating water conservation policies by province and city.In addition,neighboring provinces can take advantage of interoperability and achieve a cooperative development in order to minimize differences in agricultural water consumption within the Yangtze River Economic Zone.