基于三维生态足迹的重庆市农业用水生态效率水平测度、脱钩关系及驱动因素分析
An Analysis of Agricultural Water Eco-efficiency in Chongqing: Measurement, Decoupling Relationships and Driving Forces Based on a Three-dimensional Ecological Footprint Model
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摘要: 农业水资源的有效供给是促进农业可持续发展的关键。以农业用水为研究对象, 将农业用水三维生态足迹作为非期望产出指标纳入农业用水生态效率指标体系, 基于2015-2021年重庆市37个区(县)的面板数据集, 运用超效率SBM(slack based measure)模型和Malmquist-Luenberger(ML)生产率指数对农业用水生态效率进行静态和动态相结合的综合评价, 采用Tapio脱钩模型分析农业用水生态效率与经济增长的脱钩关系, 运用Kaya恒等式和对数平均迪氏指数(LMDI)方法分析农业用水生态效率的驱动因素。结果表明: (1)重庆市农业用水三维生态足迹整体上呈上升趋势, 主城新区最高, 中心城区最低。(2)重庆市农业用水静态生态效率总体呈增长态势, 但未能达到有效水平, 仍存在较大的提升空间; 区域生态效率空间聚集性减弱, 区域差异显著。(3)重庆市农业用水动态生态效率整体呈现先下降再上升变化, 测度结果与静态效率结果一致, 但数值要高于静态结果。中心城区增速最快, 主城新区增速最慢。农业用水生态效率主要来源于技术进步。(4)重庆市农业用水生态效率与经济增长主要脱钩类型为强脱钩、弱脱钩和扩张负脱钩, 脱钩关系并不理想。(5)重庆市农业用水生态效率主要受到经济水平的正向影响, 劳动力与技术水平对生态效率具有负向抑制作用。基于此, 建议通过改良土壤与作物种植结构、推广节水灌溉技术和完善水利基础设施等方式, 进一步提升农业用水的有效利用水平。Abstract: The effective supply of agricultural water resources is critical for promoting sustainable agricultural development. This study constructs an agricultural water eco-efficiency evaluation system by incorporating the three-dimensional ecological footprint of agricultural water use as an undesirable output indicator. Utilizing panel data from 37 districts/counties in Chongqing (2015-2021), we implemented an integrated analytical framework combining: static assessment via the super-efficiency SBM model; dynamic evolution analysis through ML productivity index; decoupling relationship examination using the Tapio model; and driving factor decomposition via Kaya identity and LMDI method. Key findings reveal: (1) The three-dimensional ecological footprint of agricultural water exhibited an upward trend, peaking in the Main Urban New Area while remaining lowest in the Central Urban Area. (2) Static eco-efficiency demonstrated gradual improvement yet remained suboptimal, with significant regional disparities and weakened spatial agglomeration, demonstrating that there's much room for improvement. (3) Dynamic eco-efficiency followed a U-shaped trajectory, outperforming static measurements, driven primarily by technological progress. Efficiency growth rates varied substantially across regions: the Central Uban Area experienced the fastest growth, while the Main Urban New Area presented the slowest growth. (4) Four decoupling states were identified between eco-efficiency and economic growth: strong decoupling, weak decoupling, and expansion negative decoupling, indicating that the decoupling relationship was not ideal. (5) Economic development exerted positive impacts while labor input and technology adoption showed inhibitory effects on eco-efficiency. Thus, to enhance agricultural water utilization efficiency, it is suggested that such measures should be taken, including optimizing soil-crop systems through structural adjustments, promoting water-saving irrigation technologies and improving water infrastructure.