The vernal equinox is from March 20 (or 21) to April 4 (or 5) end of each year. This year, the vernal equinox starts on March 21st and ends on April 5th. The vernal equinox is one of the festivals that reflect the changes of the four seasons. In ancient China, it was customary to indicate the beginning of the four seasons with the establishment of spring, summer, autumn and winter. The spring equinox, summer solstice, fall equinox and winter solstice are in the middle of the seasons. On the day of the equinox, the sun's rays directly on the equator, the earth's ` day and night time is equal, so the ancient equinox is also known as the "day and night", folk "spring and autumn equinox, day and night" of the proverb.
After the vernal equinox, most of the winter crops in southern China entered the spring growth stage. In central China, there is a "spring equinox wheat up, a moment worth a thousand dollars" of agricultural proverbs. Most of the southern region of the temperature continues to rise, but generally not as fast as the rain to the equinox period. late March average temperature in northern South China more than 13 ℃ to 15 ℃, South China more than 15 ℃ to 16 ℃. Most areas of the plateau has been snow melt ice, the average temperature of about 5 ℃ to 10 ℃. Most of the southern part of China and other valleys have the highest temperature, the average has reached about 18 ℃ to 20 ℃. South in addition to the edge of the mountainous areas, the average ten seven, eight years of average daily temperatures rose steadily to more than 12 ℃, conducive to rice, corn and other crops such as sowing, afforestation is also very suitable. However, before and after the vernal equinox in South China often have a stronger cold air invasion, the temperature drops significantly, the lowest temperature can be as low as 5 ℃ below. Sometimes there is a small cold air followed by the formation of a sustained several days of low temperature and rain, which is unfavorable to agricultural production. According to this feature, should make full use of the weather forecast, seize the cold end of the warm head timely sowing.
Vernal equinox this day direct sunlight on the equator, day and night are almost equal, the difference is that the northern hemisphere is spring, the southern hemisphere is the fall, and then the position of direct sunlight gradually north, the northern hemisphere has been a gradual increase in solar radiation, the weather is warming up day by day, while the day grows longer and shorter, the darkness of the night is gradually shorter. Vernal equinox, by the influence of the convergence of cold and warm air masses, rain is also going to be more. This is not, this year's spring equinox, the province did not have the sun patronized, replaced by a cloud layer thick, rain like a note.
As the saying goes: "Spring equinox wheat get up, fertilizer to follow. A spring rain a warm, busy plowing after the spring rain. Spring busy season is about to start, spring management, spring plowing, spring planting is about to enter a busy stage. After the vernal equinox, overwintering crops enter the growth stage, to strengthen field management. As the temperature rises quickly, the water demand is relatively large, farmers should strengthen the water storage and moisture conservation.