How about the development of agricultural technology in Song Dynasty?

A major change in agriculture in the Song Dynasty was that rice planting and yield rose to the first place in the country. This is mainly because in the early Northern Song Dynasty, rice planted in the south was popularized to the north by the policy of planting rice free of rent. Moreover, Zhancheng rice with early maturity, strong drought resistance and low requirements for soil fertility was introduced from Vietnam, and yellow rice with full grains was introduced from North Korea. In addition, wheat in the north has also begun to be vigorously promoted to the south. In the Southern Song Dynasty, Chen (date of birth and death is unknown) wrote Chen Nongshu on 1 149. This is the earliest book about agricultural technology in southern rice areas in China. All previous agricultural books were mainly based on agricultural production technology in northern China.