Temporal and Spatial Analysis: The Impact of Virtual Water Flows on Agricultural Production Efficiency in China

Panel data from 30 provinces in China spanning the years from 2007 to 2022 were selected. Regional virtual water flows were calculated based on the principle of social equity, and agricultural production efficiency was measured using the Super-SBM model, which overcomes the issue of being unable to measure efficiency values when they exceed 1 for decision-making units. Based on the aforementioned estimation results, methods such as ArcGis and kernel density estimation were employed to illustrate the changing trends of virtual water flows and agricultural production efficiency in key years. Additionally, a fixed-effects model was used to explore the relationship between the two. The following conclusions are drawn: (1) The overall pattern of virtual water trade in grain exhibits a “north-to-south grain transportation” flow, with the volume of transfers increasing annually, which is contrary to the spatial distribution of water resources. Regions with a net outflow of virtual water in grain are mostly concentrated in major grain-producing areas such as the northeast, while provinces with a net inflow are mainly concentrated in economically developed regions such as South China, Southeast China, and the middle and lower reaches of the Yangtze River. (2) The average agricultural production efficiency shows a fluctuating upward trend, with an overall “S”-shaped pattern in a horizontal view, and the overall differences in production efficiency among provinces have widened. (3) Agricultural production efficiency exhibits an inverted “U”-shaped trend with the increase in virtual water flows, a conclusion that remains valid after a series of robustness tests. Therefore, corresponding suggestions are proposed based on the above conclusions, including formulating a scientific virtual water trade strategy and improving agricultural production efficiency.