Economy of The Song Dynasty - Agriculture

Agriculture

There was a massive expansion of ploughland during the Song dynasty. The government encouraged people to reclaim barren lands and put them under cultivation. Anyone who opened up new lands and paid taxes were granted permanent possession of the new land. Under this policy, the cultivated land in the Song Dynasty is estimated to have reached a peak number of 720 million mu, and was not surpassed by later Ming and Qing Dynasties.

Irrigation of arable land was also greatly fostered during this period. Prominent statesman and economist Wang Anshi issued the Law and Decree on Irrigation in 1069 that encouraged expansion of the irrigation system in China. By 1076, about 10,800 irrigation projects were completed, which irrigated more than 36 million mu of public and private land. Major irrigation projects included dredging the Yellow River at northern China and artificial silt land in the Lake Tai valley. As a result of this policy, the crop in China tripled. Agricultural yields were about 2 tan (a unit of about 110 pounds or 50 kilograms) of grain per mu during the Song Dynasty, compared with 1 tan during the early Han and 1.5 tan during the late Tang.

The economic development of China under the Song dynasty was marked by improvements in farm tools, seeds, and fertilizers. The Song government inherited the curved iron plough invented in the Tang Dynasty (618–907) as described in detail in Lu Guimeng's The Classic of the Plough. The Song Dynasty improved on the Tang Dynasty curved iron plough and invented a special steel plough design specifically for reclaiming wasteland. The wasteland plough was not made of iron, but of stronger steel, the blade was shorter but thicker, and particularly effective in cutting through reeds and roots in wetlands in the Huai River valley. A tool designed to facilitate seedling called "seedling horse" was invented in Song Dynasty; it was made of jujube wood and paulownia wood. Song Dynasty farms used bamboo water wheels to harness the flow energy of rivers to raise water for irrigation of farmland.

The water wheel was about 30 chi in diameter, with ten bamboo watering tubes fastened at its perimeter. Some farmers even used three stage watering wheels to lift water to a height of over 30 chi.

High yield Champa paddy seeds, Korean yellow paddy, Indian green pea, and Middle East watermelon were introduced into China during this period, greatly enhancing the variety of farm produce. Song farmers emphasized the importance of night soil as fertilizer. They understood that using night soil could transform barren wasteland into fertile farmland. Chen Pu wrote in his Book of Agriculture of 1149: "The common saying that farmland becomes exhausted after seeding three to five years is not right, if frequently top up with new soil and cure with night soil, then the land becomes more fertile".