Twenty-four solar terms: vernal equinox

March 2 1 day is the vernal equinox among the 24 solar terms. The vernal equinox solar terms begin when the sun moves to the Yellow River at 0 degrees. This day is half a spring, so it is called the vernal equinox. On this day in spring, the sun shines directly on the equator, and day and night are almost equal. After that, the direct sunlight gradually moved northward, and the days were long and the nights were short.

In spring, the East Asian trough is obviously weakened, and the ridge activity in the westerly belt is obviously enhanced. From Mongolia to the northeast of China, there are often low-pressure activities and cyclones. Low pressure activities bring cold air to the south, while strong winds cool the cold air in the north. When the long wave trough moves eastward, under the influence of the intersection of cold and warm air masses, there will be continuous rainy and cold weather in late spring.

Proverbs about vernal equinox and solar terms can be divided into four categories: one is about the equal length of day and night, such as "vernal equinox and autumnal equinox divide day and night equally" and "eat vernal equinox and grow a line every day"; One is to predict the late weather according to the sunny and rainy days at the vernal equinox, such as "there will be rain at the vernal equinox and flood at the autumn equinox"; One is to predict the weather in the later period according to the cold and warm weather, such as "the vernal equinox is not cold" and "the vernal equinox is not warm and the autumn equinox is not cold". Another is to predict the weather in the later period according to the wind, such as "the west wind is rainy at the vernal equinox", "the vernal equinox is warm, wet in May and then dry and sunny" and so on.

Spring and summer crops have entered the spring growth stage, so field management should be strengthened. Planting cotton in nutrition bowl should choose cold tail and warm head, and proceed in time.