What are the characteristics of paddy field cultivation techniques in ancient southern China?

South China refers to the vast area south of the Huaihe River in Qinling Mountains, where rice is mainly grown? In ancient southern China, rice cultivation was mainly carried out by raising seedlings and transplanting. Soil cultivation requires flat fields and rotten soil to facilitate transplanting? This is obviously different from dryland agriculture in the north? The paddy field cultivation technology in South China has gradually formed a technical system of paddy-upland rotation and combination of paddy and upland, and paddy field cultivation has formed a trinity of tillage, harrowing and tillage. Dry farming adopts the techniques of "ditching", soil preparation and drainage, which improves the farming techniques of ridge farming and flat farming?

During the Qin and Han Dynasties, the southern part of China was still a region with a vast territory and a sparse population and backward production, and extensive farming techniques such as fire tillage and hydroponics were mostly used. Simply put, burning water is burning weeds and irrigating water to grow rice? This is recorded in many history books?

The Book of Pinghuai quoted the imperial edict of Emperor Wu of the Han Dynasty in dealing with the victims in Shandong: "The south of the Yangtze River will be burned and the hungry will be fed between the Yangtze River and the Huaihe River?"

Seven or eight hundred years later, when "Geography of Sui Shu" recorded the paddy field farming methods in the south of the Yangtze River, it was also said that "the customs of the south of the Yangtze River, burning water, eating fish and rice, and fishing and hunting were the businesses"?

Judging from the above records, from the Han Dynasty to the Sui Dynasty, the cultivation of paddy fields in the south of this period was summarized as "burning paddy fields" in Yan Tie Lun Tong You Pian, Han Shu Wu Di Ji, Han Shu Geography and many poems of the Six Dynasties.

At the beginning of the Tang Dynasty, some people still called Jiangnan "the black phoenix poured it, and the fire plowed the water"? This farming method has been going on for 800 years or more without any change?