The Rice-Fish-Duck system in Congjiang County of southwest China's Guizhou Province has a long history and is a unique model of sustainable use of water and soil resources. The approach by the Dong people saves resources by growing rice, fish and ducks in the same paddies. By leveraging the differences in the cultivation periods of rice, fish and ducks, a self-improving food chain model has been formed in the paddy fields. It is a virtuous eco-cycle in which traditional methods of farming and folk customs are harbored.