Double-Cropping Rice in Jiangnan

Timeline

1. 1000–1127Suzhou · JiangsuDuring the Northern Song, Jiangnan polder-field hydraulics and rice-growing techniques steadily improved; farmers began experimenting with replanting late rice after the early rice harvest, combined with river-network irrigation and green manure, laying the technical and hydraulic foundation for the double-cropping system.
2. 1127–1220Lin'an · ZhejiangAfter the Song court moved south, population and tax burdens shifted southward; Jiangnan farmers systematically perfected the early-late rice double-cropping rotation, combined with the introduction of early-maturing varieties such as Champa rice and maintenance of polder hydraulics, significantly raising annual output per unit of cultivated land and supporting the capital's and towns' grain supply.
3. 1221–1230Liangzhe Circuit · Liangzhe CircuitBy the 1220s, double-cropping rice had become the norm in Liangzhe, Fujian, and Jiangxi; farmers scheduled early rice transplanting and late rice replanting according to the solar terms, with mature polder hydraulics and manure application; Jiangnan became the Southern Song's most stable grain base, supporting the finances and military supplies of the Ningzong and Lizong reigns.
4. 1279South of the Yangtze · JiangnanDouble-cropping rice expanded further into South China during the Yuan, Ming, and Qing, becoming one of the most important agricultural technological legacies in Chinese economic history; modern hybrid rice and mechanization continued to evolve on this basis, and Jiangnan remains one of China's principal rice-producing regions to this day.