China has a long history of rice cultivation. In ancient books such as "Guanzi" and "Lu Jia Xinyu", there are records of sowing "five grains" in the Shennong era of about 27th century BC. Rice is listed as one of the five grains. one. "Historical Records·Xia Benji" records that "Yu ordered rice to benefit the common people, so that it can be planted in humid areas", which shows that in the 21st century BC, the Chinese people had already begun to fight against nature, dredge the "Nine Rivers", and use the "humid rivers". Develop rice in wet areas. About 4,200 years ago, rice cultivation has advanced from the middle and lower reaches of the Yangtze River to the middle reaches of the Yellow River. During the Warring States Period, due to the application of iron farm tools and plows, intensive farming began. At the same time, large-scale water conservancy projects were built for the development of rice, such as the Zhangshui Canal in Hebei (445-396 BC), Dujiangyan in Sichuan (256 BC), Zheng Guoqu of Shaanxi Province (246 BC), etc. Terraces first appeared in Sichuan during the Western Han Dynasty. In the 630s of the 6th century, Jia Sixie of the Northern Wei Dynasty's "Essentials for Qi Min" specifically described water and upland rice cultivation techniques. The "Guangzhi" of Jin Dynasty also records the development of green manure in rice fields to increase the source of organic fertilizer and improve soil fertility. It reflects that the rice planting technology at that time had reached a certain level. After the Wei, Jin, Southern and Northern Dynasties, China's economic center of gravity gradually moved southward. During the Tang and Song Dynasties for more than 600 years, Jiangnan became the center of rice production in the country. The Taihu Basin became the rice production base. All the rice needed by Beijing's military and civilians depended on water transportation from the south of the Yangtze River. At that time, due to the emphasis on water conservancy construction, reclamation of rivers, lakes and sea troughs, improvement of agricultural tools, soil fertilization, double cropping of rice and wheat, and variety renewal, a relatively complete system of patchwork cultivation was initially formed in the Jiangnan rice area. China is rich in rice seed resources. By the end of the Ming Dynasty and the beginning of the Qing Dynasty, the number of rice varieties in 223 prefectures and counties in 16 provinces recorded in the "Zhi Provincial Chronicle" reached more than 3,400. In addition, new progress has been made in seedling cultivation, water and fertilizer management, etc. Since the founding of the People's Republic of China in 1949, on the basis of inheriting and developing the fine traditions of intensive farming in the past, and using modern agricultural science and technology, rice production has achieved great development. By 1984, the country's rice planting area reached 33.178 million hectares, with an average yield of 5370.0 kilograms per hectare, and the total rice output reached 178.255 million tons, which were approximately 29%, 170% and 266% higher than in 1949 respectively.