Champa rice

Timeline

1. 900–1011Coastal plains of the Champa kingdom · ChampaChampa farmers bred rice with shorter growth cycles and stronger drought tolerance in the tropical monsoon environment, adapting to local rain and heat conditions and providing the varietal basis for later northward spread.
2. 1012–1030Huainan, Liangzhe, and other areas · LiangzheSong Zhenzong sent envoys to obtain rice seed from Champa and ordered Jianghuai officials to promote its cultivation; its early-maturing traits allowed some areas to achieve rice-wheat double cropping or shorten the growth cycle, opening the way for transformation of Jiangnan's agricultural structure.
3. c. 1131–1140Jiangnan East Circuit, Liangzhe Circuit · JiangnanAfter the Jingkang Incident, northern populations migrated south; Champa rice spread further across Jiangnan hills and plains, combined with water conservancy repairs and polder development, supporting grain supply for military needs and the tax base in the early Southern Song.