Why do you say "a year's plan lies in spring"?

A year's plan starts with spring. How did spring come? Astronomically speaking, the alternation of seasons in a year is determined by the orbital position of the earth around the sun. At different times, the earth is in different positions in its orbit around the sun and receives different sunlight in different places on the earth. So there will be a big difference between cold and heat. The four seasons of the earth are not only periodic changes in temperature, but also periodic changes in the length of day and night and the height of the sun, which leads to changes in spring, summer, autumn and winter. In short, it was formed during the rotation of the earth.

According to the degree change of solar longitude (solar longitude or celestial longitude), the ancient summer calendar created 24 solar terms. Every 15 degrees, the longitude of the Yellow River is a solar time. Then, according to tradition, the season of the year is in spring, which follows the ancient summer calendar, that is, the current lunar calendar, which means that farmers will start farming and sowing in the spring when the four seasons begin.

Spring is the season for planting crops. Spring has come, which makes hibernating animals, sleeping plants and migrating birds feel warmer in winter. In spring, the northern hemisphere of the earth began to tilt towards the sun, receiving more and more direct sunlight, the temperature began to rise, and the ice and snow gradually melted. The water level of the river also began to rise. Everything needs a certain temperature, humidity and light to grow. Spring is the transitional season between winter and summer.

In spring, the temperature begins to rise and the light begins to increase. Sowing at this time will promote crop growth and accumulate accumulated temperature at a suitable temperature. But the light at this time is not as strong as in summer, which can provide the required light intensity for crops. In spring, plants begin to sprout and grow, many flowers bloom, and birds begin to migrate to find their most comfortable environment. During this period, many animals are also in estrus, so China also calls spring the season of "the revival of everything". For farmers, spring is the season to sow crops. However, the study of spring is not limited to this. The deeper metaphor is to warn people to make all plans as early as possible, grasp and do as early as possible, and do more as early as possible to lay a good foundation for the work throughout the year.