跨流域调水背景下粮食区域贸易对 粮食种植结构的影响——基于“实体水-虚拟水”流动视角.

Water is the lifeblood of agriculture. Different from land resources, water resources can flow across regions. Based on the perspective of ‘physical water and virtual water’ flow and using the panel data of 31 provinces (autonomous regions and municipalities) in China from 2004 to 2020, this paper used the dynamic spatial Durbin model to estimate the impact of regional grain trade on the pro⁃ portion of grain planting and that of rice, wheat, and corn in the context of inter-basin water transfer. The results showed that: ① For grain output areas, the impact of ‘physical water and virtual water’ flow decreased, the overall proportion of grain planting increased, and the proportion of corn planting among the grains decreased. It showed that the increase of water resource pressure in grain output areas played a greater role in promoting the induced technological change of grain production and strengthening the regional production division than limiting them, and there was a ‘paradox of irrigation efficiency’, that is, the progress of water-saving technology led to the increase of high water consumption crops. ② For grain input areas, the impact of ‘physical water and virtual water’ flow increased, the proportion of grain planting decreased, the proportion of short-term rice and corn planting increased, the proportion of rice (high water consumption crop) planting increased more, the proportion of long-term rice and corn planting decreased, and the proportion of corn (low water consumption crop) planting decreased more. It showed that the regional division of labor and strengthening of grain production reduced the proportion of grain planting in grain input areas, but the internal structure of grain was developing in the direction of more water consumption. ③ Under the current ‘physical water and virtual water’ flow, the grain input areas had a negative spatial spill⁃ over effect on the grain planting proportion in the output areas and the corn planting proportion among the grains, which showed that the reduction of water resource pressure in the grain input areas had a negative impact on the grain production in the grain output areas, and intensified the phenomenon of ‘paradox of irrigation efficiency’ in the internal structure of grain. The grain output areas had no significant impact on the grain planting proportion in the grain input areas. In the short term, the planting proportion of rice and corn was reduced, and the planting proportion of rice, a high water consuming crop, was reduced more, the planting proportion of rice and corn increased in the long term, and the planting proportion of corn, a low water consuming crop, increased more, indicating that the grain out⁃ put areas promoted the development of the internal structure of grain in the grain input areas in the direction of water saving. Finally, this paper puts forward the policy implications of implementing the overall management of ‘physical water and virtual water’, vigorously promoting the development of water-saving agriculture in grain output areas, and establishing regional grain virtual water compensation systems. [ABSTRACT FROM AUTHOR]