China faces a water shortage issue, especially for agriculture. The study looked at how grain production and trade impact water resources from 2004 to 2013. They found that the North imports water-intensive products from the South and exports water-extensive products. This leads to a large transfer of water resources from North to South, with about 10% of irrigation water in the North used for crop production being transferred annually. The South-North Water Diversion Project helps somewhat, but more focus is needed on managing water demand rather than just increasing crop trade between regions.