Phenology of slight cold solar terms

In ancient China, the slight cold was divided into three stages: the first stage was Yanbei Township, the second stage was that magpies began to build nests, and the third stage was that pheasants began to swim.

These geese began to migrate from the warm areas in the south to the north. Although this migration did not completely reach the northernmost part of China, they continued to stay away from the tropics in summer. At this time, the magpie sensed the smell of yang and began to build a nest. This is the response of birds to the recovery of yang in spring. Pheasants also felt the growth of yang and began to sing, which is a further confirmation of the coming spring.

According to China's long-term meteorological records, the slight cold solar terms are colder than the severe cold solar terms in the north, and there is a saying that slight cold is better than severe cold in the north. However, for some areas in the south, the lowest temperature in the whole year will still appear in the great cold solar terms, while the slight cold in the north of China is colder than the great cold, because there is less surface residual heat, which has been released to the minimum by the slight cold.

rural activity

Due to the large span between north and south in China, different regions will have different production agriculture for the same slight cold solar terms. There is not much farm work in most parts of the north, so we have winter vacation. The main tasks are heat preservation, fertilization and fertilizer accumulation in vegetable pits and sheds. In the south, winter fertilizer should be applied to crops such as wheat and rape, while in Hainan and most parts of South China, it is mainly to prevent cold and freeze and store fertilizer.

As the saying goes, the winter practice lasts for three or nine days, and the slight cold solar term lasts for three or nine days. That is to say, the solar term from the winter solstice starts to count as nine days, with a cycle of nine days, in which 18 to 18 is called Erjiu, 19 to 27 is called Erjiu, and so on. The slight cold solar term is between 29 and 39, which can be said to be the coldest in a year.