The varieties of rice, in the early written records of the "Guanzi - ground staff" chapter, recorded the names of 10 rice varieties and their suitable soil conditions for planting. Later generations of agricultural books and even some poetic writings, there is often a description of rice varieties.
China's ancient working people in the process of rice cultivation, in the type of paddy field, farming time, sowing and seedling, irrigation, fertilization, pest control, harvesting, etc., has accumulated a wealth of experience.
Yuan dynasty agronomist Wang Zhen's "Book of Agriculture" divided fields into nine categories: well fields, district fields, nursery fields, paddies, cabinet fields, rack fields, terraces, painted fields and sand fields. The six categories related to rice cultivation are paddy field, cabinet field, rack field, terrace field, tu field and sand field.
The paddocks in the Taihu Lake area originated in the Spring and Autumn Period, and were gradually developed from the Warring States Period to the Qin Dynasty, and further expanded in the Han Dynasty. Early reclamation, because the water surface is large, the downstream water drainage is smooth, food production increased significantly.
In order to solve the flooding problem, the ancients will be the paddock and excavation of ponds at the same time, which gradually formed a cross-pond longitudinal Pu of the coccyx, around the Weiqibu of the ponds of the Weiqibu polders system.
Shelf field, also known as turnip field, is in the swamp with wooden stakes as a frame, selecting water plants such as Mushroom root and soil mixed, spread on the shelf, planting rice. Crops planted in this way float on the water surface, with the water high and low, not flooded. In the Song and Yuan dynasties, there were such rack fields in Jiangnan, Huaidong and Liangguang.
The ancients in order to expand the arable land, to the mountainous areas to the field is terraced, to the water to the field is the paddock. Such as Sichuan, Hunan and other provinces of the "edge of the field", northern Guangdong and Gandong "row of fields". There are also ancient books called "mouth field", "thunder field", "mountain field", "rock field" and so on.
On the farming system of rice, rice is generally grown only one season a year. Since the early rice varieties, planting range gradually to the Yellow River Basin, where the summer sunshine is longer, and in the southern part of the local area, it can be planted two or even three seasons a year. For example, the emergence of three-season rice in the Ming Dynasty is.
From the song dynasty to the qing dynasty, double-season intercropping rice has been fujian, zhejiang coastal area of the main farming system; double-season rice proportion is very small. Winter wheat was planted in late rice fields in the Taihu Lake basin from the Tang and Song dynasties, and continues to this day.
The above farming systems, gradually formed throughout history, are the reasons for the increase in the compound seed index in China's rice areas and the continuous increase in grain production, while soil fertility has never declined.
After the primitive rice farming was differentiated into dry rice and water rice, rice was initially direct seeded. North and South are the same. As for the invention and application of seedling technology, the reasons are different. The northern seedling transplantation, out of the mitigation of grass, the southern seedling transplantation, although the same role in mitigating grass, but with the development of replanting system is closely related to the development of the system, especially after the development of multi-cropping
System, transplantation is to solve the seasonal contradiction of the effective measures.
The irrigation water for rice was initially utilized in natural rivers, which were opened up into rice paddies where rice could be planted by digging large and small ditches, storing water in sloping ponds, and preventing the intrusion of external water with embankments, and other measures, which were already quite well-developed farmland water conservancy projects. Typical, for example, is the Dujiangyan, which has been in use for more than 2,000 years and is the basic guarantee of Sichuan's granary.
The focus of rice production in the south, the Qin and Han dynasties in the south is not fully developed, so the water conservancy repair more to the north, to the Tang and Song dynasties later, the center of gravity of the national economy moved to the Yangtze River Basin, the population increased, rice paddies opened up, and the guarantee of water conservancy conditions are also followed by the development of very soon. In addition, the ancients in the field high water low places with turning carts, tube wheel, bailing bucket, orange pulley and other irrigation tools.
On the irrigation technology of paddy fields, as early as in the Western Han Dynasty, "Flood Sheng Zhi Shu" that is, there is a pithy account: rice seedlings in the spring when the weather is still cold, the water temperature to keep warmer, so that the field of water to stay in the field, more sunshine, so the water inlet and outlet to be in the same straight line. In summer, to prevent the water temperature from rising too quickly, let the water inlet and outlet staggered, so that the field water flow, which is conducive to cooling.
Discussions on fertilization of paddy fields were first seen in the Southern Song Dynasty agronomist Chen Jie's "Chen Jie's Book of Agriculture". Among them are the arguments that the ground can always be new and strong, using manure as medicine and applying fertilizers according to soil conditions, which are still of guiding significance today.
In the relationship between base fertilizer and fertilizer applied to rice, all generations of agricultural books are heavy base fertilizer, because the fertilizer is the most difficult to grasp. But the long period of practical experience so that the ancient farmers gradually created a look at the seedling color fertilizer technology, which in the late Ming Dynasty "Shen's agricultural book" has a detailed account.
Tangpu dike system