Pigeons sing on the house in spring, and apricot flowers are white on the edge of the village. What is phenological knowledge?

Apricot Blossom White means that in mid-April, China has the solar term Grain Rain, which is the last solar term of the Spring Festival. It is the best season for seedlings, transplanted melons and beans. The arrival of solar terms in Grain Rain means that the cold wave weather basically ends and the temperature rises rapidly, which is very beneficial to the growth of cereal crops. The ancients further divided Grain Rain into three stages: the first stage was when Ping began to live; The second time, the cuckoo blows feathers; For the third time, Dai Sheng fell on the mulberry tree, among which the cuckoo is the cuckoo, and the cuckoo sings to remind people not to delay sowing in farming season. Therefore, the phenological knowledge contained in the evidence poem is that the cold of late spring has passed, the earth is warming up, and spring ploughing begins.