The Spatial And Temporal Evolution Of Green Agricultural Water Use Efficiency In The Yangtze River Economic Zone And Its Dominants

Water scarcity and famine are two of the most significant challenges facing humanity.Improving the efficiency of agricultural water resource use can effectively alleviate these issues.The Yangtze River Economic Belt is an important food-producing region in China,and analyzing its agricultural water use efficiency patterns can offer valuable guidance for agricultural development in the basin and beyond.However,the environmental externalities of agricultural production have been overlooked in current research on agricultural water efficiency,leading to misguided agricultural investment and policy decisions.Additionally,the application of organic biomass fertilizers can cause bias in measuring the grey water footprint of agriculture by fixing nitrogen.Therefore,it is crucial to eliminate fixed nitrogen from agricultural systems,improve the accuracy of the grey water footprint of agriculture,and use this measure to assess the externalities of agricultural production accurately.Ultimately,obtaining a green efficiency of agricultural water resources will enable a proper understanding of the current situation of green water use in agriculture.Unlike previous studies,this research considers the agricultural grey water footprint as an undesired output and takes into account the errors caused by nitrogen fixation in agriculture when calculating the agricultural grey water footprint to obtain the agricultural green water resource efficiency.By analyzing nitrogen fixation intensity,grey water footprint emissions,and green water efficiency of agricultural water resources in 11 provinces and cities in the Yangtze River Economic Zone from 2000 to 2020,this study compares the differences in green water efficiency of agriculture under two models of integrated planting-livestock production and separate planting-livestock production.The Logarithmic Mean Index Method(LMDI)is used to decompose agricultural nitrogen fixation intensity,revealing the spatial and temporal variation patterns and internal links between the green efficiency of agricultural water resources and the grey water footprint of agriculture.This analysis leads to three main conclusions:(1)the influencing factors and fluctuation patterns of nitrogen fixation intensity,(2)the relationship between the spatial and temporal variation of the agricultural grey water footprint and its geographical distribution,internal structure,and the regional economy,and(3)the spatial and temporal patterns of variation and factors influencing the green efficiency of agricultural water resources.