Agricultural Water-Land Nexus In The Middle And Lower Reachs In Yangtze River Drivern By Comsumption And The Regulation Strategies

Agricultural land and water resources are crucial limiting factors for food production,and their balanced management is meaningful for improving agricultural productivity and ensuring food security.As a core area of agricultural production and a key economic development zone in China,the middle and lower reaches of the Yangtze River face the problem of uneven distribution of agricultural water and soil resources in the process of agricultural intensification,which restricts their agricultural production efficiency and sustainable development.Meanwhile,deepening trade integration has led to some cities buying agricultural products and services from other regions to meet local consumption needs,resulting in the transfer of hidden agricultural land and water resources in traded goods between regions and further affecting the matching of agricultural land and water resources.Moreover,population growth,economic development,and changes in consumption patterns,and other socioeconomic transformation factors can change the degree and direction of this impact.Therefore,conducting a nexus analysis of virtual agricultural water and land resources caused by consumption and exploring the linkage between the two under the situation of socio-economic transformation can help optimize and regulate the agricultural land and water resources in the middle and lower reaches of the Yangtze River.Based on this,this study used the method of per unit area water resources to clarify the baseline of the water and soil resource matching in the middle and lower reaches of the Yangtze River.Using the multi-regional input-output method,the study analyzed the virtual agricultural water and land footprint caused by consumption and virtual agricultural water and land transfer in a typical year in the region.The study also used structural decomposition analysis to identify the main socio-economic driving factors of changes in the agricultural water and land footprint.Additionally,combining with association theory,the study constructed a framework for the association between water resource consumption and land resource utilization,as well as virtual water resource and virtual land resource,from multiple perspectives such as "spatial and temporal correlation of agricultural water and soil matching," "correlation of agricultural water and soil resource efficiency," and "dynamic correlation of agricultural water and soil footprint." Finally,the study simulated the changes in agricultural water and soil utilization and their association under different social transformation models,providing reference strategies for optimizing and regulating water and soil resources in the middle and lower reaches of the Yangtze River.The main results are as follows:(1)From 2012 to 2017,the water and soil matching in the middle and lower reaches of the Yangtze River showed a spatial distribution pattern of "low on the north bank and high on the south bank," and the overall matching degree showed a trend of first increasing and then decreasing.(2)Economically developed and densely populated cities,such as Wuhan,Nanjing,and Changsha,consume a larger agricultural water and land footprint,and tend to import goods with a high water or land content from smaller cities with high co毫米ercialization of agricultural products,such as Tongling,Huaibei,and Chizhou,to alleviate local water and soil resource pressure.(3)From 2012 to 2017,the overall agricultural water and land footprints in the middle and lower reaches of the Yangtze River showed a decreasing-increasing trend.Different driving factors contributed differently to the changes in the two footprints.The agricultural water intensity effect and economic development effect had the largest contribution to the changes in the agricultural water footprint,with contribution rates of-45.43% and 44.12%,respectively.The agricultural land use intensity effect and economic development effect had the largest contribution to the changes in the agricultural land footprint,with contribution rates of-46.54% and 43.81%,respectively.(4)Results from a multi-perspective analysis of the water-soil association in the middle and lower reaches of the Yangtze River show that: the spatiotemporal correlation analysis based on the Moran index indicates a significant positive correlation between the agricultural water and soil matching degree in the region,which is gradually increasing,and two urban clusters with "high-high" and "low-low" agricultural water-soil matching degree are formed on both sides of the Yangtze River,respectively,affected by the radiation of high or low agricultural water-soil matching degree.The correlation analysis of the agricultural water and land resource matching efficiency based on MRIO indicates that in 2012,2015,and 2017,there were 16,17,and 17 key cities with high water resource consumption and high land resource utilization,which are mainly located in the middle reaches of the Yangtze River.The dynamic correlation analysis of the agricultural water and soil footprint based on SDA indicates that the degree of synergy between the two types of footprints is different in different time periods(2012-2015 and 2015-2017),with a higher degree of synergy in the latter(95.13%)than in the former(83.13%).Furthermore,the contribution of different driving factors to the dynamic correlation of the two types of footprints is different,with the resource intensity effect being the most significant,followed by population growth,economic development,and industrial restructuring,while the change in demand structure has almost no contribution.