Thread by @lefineder

Under the Qing dynasty, China experienced a massive expansion in population, growing from 50-150 million persons in the Ming Era to around 400 million by the mid 19th century.

The main reasons for this extraordinary expansion🧵

Was first its military expansion, by 1760, the Qing, under the "Ten Great Campaigns of conquest," had incorporated a massive amount of new land.

In the following decades, a mass movement of Han people into this new farmland significantly expanded agricultural production.

Another equally important factor is an increase in crop yields.
Data on rice yields shows a slight improvement over time, but a far greater factor is the introduction of new world crops into China.

Qing data from over 1300 counties relating to whatever maize is grown in the county allows us to map the spread of New World crops in China.

From the end of the Ming to mid 19th century, maize went from being utilized in 10% of counties to all counties.

Consequantly multiple studies indicate a significant increase in crop yields per mu of land over this period.

Another possible factor is a relative decline in the frequency of natural disasters.

Interestingly, the combined effects of the decline in mortality due to the decrease in disasters and of the increase in population possibly meant that the situation in China was becoming more Malthusian, with per capita GDP declining toward subsistence.

Graphs from:
"China’s Extraordinary Population Expansion and Its Determinants during the Qing Period, 1644-1911" - Kent Deng.
And also from the Cambridge Economic History of China, vol 1