The grain crops in the north and the south are interactive in different periods.
China is an important grain country, and people have been planting grain on a large scale since the Neolithic Age. However, affected by the natural geographical environment and production technology, the production cycle of each grain is different. Some crops with strong vitality and adaptability can grow in a wider geographical area, such as wheat, rice, millet and millet. However, some crops can only reproduce in a specific environment, such as some tropical crops, which are very regional.
In different historical periods of our country, the grain crops in the north and the south have influenced each other. In addition, there are some exotic crops, such as potatoes, peanuts and sweet potatoes that we eat today, all of which are foreign goods.
1. The formation and change of grain structure in China from prehistoric times to Qin and Han dynasties.
Most of the food crops in the historical period were inherited on the basis of prehistoric agriculture. At present, through archaeological discoveries of various cultures, we can know that the distribution of crops in China is different between the north and the south, with millet as the main crop in the north and rice as the main crop in the south.
The definition of "five grains" is constantly changing.
Millet has appeared in Longshan culture, Yangshao culture, Majiayao culture and Qijia culture known in the north. Millet has also been found in areas outside the Yellow River basin, such as Karuo culture in Tibet and Ang Ang Creek culture in the northeast.
By the middle of Yangshao culture, millet had been planted in large areas in the Central Plains, which not only met people's demand for stable grain, but also provided a foundation for the development of civilization and the formation of a larger human settlement.
In the south of prehistoric society, rice was the main food crop, such as Daxi culture, Liangzhu culture and Qujialing culture in the Yangtze River basin. Although rice also appears in the Yellow River Basin, its geographical distribution is very limited, and only the Weihe River and Luo Yi River Basin have found traces of rice. During the Shang and Zhou Dynasties, wheat originated in West Asia began to be introduced into China.