EXPANSION OF RICE CULTIVATION IN IMPERIAL CHINA
Wet rice cultivation required the warmer and wetter climate that is present in South China. The vast territory controlled by Imperial China was generally categorized into distinctive geographic regions of north and south. The west-east stretching boundary region that separated northern China from southern China was formed by two major topographical features with the Qingling Mountains dominating the boundary region in the west and the Huai River controlling the boundary region in east. The most prominent topographical feature of northern China is the Yellow River, while the most prominent topographical feature of southern China is the Yangtze River.
The Middle Imperial Period began with the Sui Dynasty in 581 and ended with Song Dynasty in 1279. During the Middle Imperial Period from 609 to 1200, the population of northern China shrank 3.8% from 31.4 million to 30.2 million people and the population of southern China grew 629.8% from 10.3 million people to 75.3 million people. In 609, 75.3% of people lived in the north and 24.7% lived in the south. In 1200, 28.6% of people lived in the north and 71.4% of people lived in the south. The demographic distribution of Imperial China between the north and the south essentially reversed from 609 to 1200, with southern China increasing from one-fourth to three-fourths of the total population and northern China decreasing from three-fourths to one-fourth of the total population.
During the reign of the Sui Dynasty from 581 to 618, the major waterways of the Grand Canal were constructed between the Yellow River in the northern capital region and the Yangtze River in the southern rural region. The Grand Canal was the main transportation system that supported the proliferation of rice farming because it enabled crops grown in the south to be efficiently shipped to distant end markets in the north.
During the Tang Dynasty from 618 to 907, China initially flourished in the early Tang period with peace and stability until the outbreak of the An Lushan Rebellion in 755 began a long era of regional instability throughout northern China. Although the Tang Dynasty were ultimately able to quell the An Lushan Rebellion after nearly 14 years of gruesome warfare, Imperial China had sustained such devastating losses that the strength of the central authority in the north became dwarfed by the power of regional military governors. Until the Song unification in 960, Northern China would continue to face many periods of rebellion and warfare that caused a significant southward population shift.
During the Northern Song Dynasty from 960 to 1127, the reestablishment of strong centralized imperial rule in China created a historic era of economic expansion and technological advancement that greatly improved farming practices for wet rice cultivation. There were innovations in wet rice agriculture with fertilization techniques for enriched soil, seed varieties for greater yields, and engineering designs for superior irrigation
During the Southern Song Dynasty from 1127 to 1279, the imperial capital in the north was lost to foreign invasions and relocated to the south that accompanied large populations of refugees to migrate to the south. Initially, large numbers of migrants settled along the Yangtze River near the imperial capital. Following significant territorial gains by the Mongols, more migrants settled further southward around the Pearl River and reclaimed significant coastal lands for rice cultivation.
Canal construction supported the proliferation of rice farming because it enabled crops grown in southern China to be efficiently shipped to distant end markets in the north. Regional instability throughout northern China compelled significant populations of migrants to relocate in the south. Technological innovation greatly improved farming practices for wet rice cultivation. Foreign invasion in northern China provoked large refugee populations to flee southward.
Robert Hartwell, “Demographic, Political, and Social Transformations of China, 750-1550,” Harvard Journal of Asiatic Studies 42, no. 2 (Dec. 1982): 369.