How did sweet potatoes affect population growth in south China?

The introduction of sweet potatoes to China in the 16th century played a pivotal role in supporting rapid population growth during the Qing period.12

As a crop originating in the Americas, the sweet potato provided a robust agrarian foundation that allowed for the cultivation of marginal, hilly, and sandy lands that were previously unsuitable for traditional staples like rice. By enabling the use of these "virgin heights" and remote mountain districts, sweet potatoes significantly expanded the total amount of productive land available for food production.34

Beyond increasing the overall food supply, the sweet potato served as a critical form of insurance against famine. This reliability helped stabilize the food supply, allowing the population to expand even in areas where indigenous cereals could not thrive. Consequently, the adoption of these New World crops facilitated a period of sustained demographic increase, with China’s population doubling between 1762 and 1834.345