Why can farmers in the Sichuan Basin grow crops for nearly the entire year?

Farmers in the Sichuan Basin are able to grow crops for nearly the entire year primarily because the region is sheltered from cold polar air masses by the surrounding mountains. This protective geography results in a mild, humid climate that is significantly warmer than would otherwise be expected for the region's latitude.123

The eastern basin experiences more than 300 frost-free days annually, which facilitates a nearly year-round growing season. This favorable climate, combined with fertile soil and sophisticated irrigation systems—such as the ancient Dujiangyan system—allows for highly intensive land use and a diverse range of agricultural production. While some areas utilize a dongshuitian (winter water-storage field) system where fields are left fallow during the winter to store water for spring paddy fields, the overall environmental conditions remain conducive to continuous agricultural activity.1432