What is the relationship between long summer climate change and agricultural activities?

Long summer is a long summer on May 5 or 6 every year, when the sun reaches 45 degrees of the Yellow Meridian. According to the classification of meteorology, only when the average daily temperature exceeds 22 degrees for five consecutive days can summer really enter.

At this time, only the southern region really enters the summer. At this time, some parts of the northeast and northwest have just entered the spring, and the average temperature in most parts of the country is between 18 and 20 degrees, which is the mid-spring and late-spring season of "all kinds of red and purple contending for the wild".

The daily average temperature in the middle and lower reaches of the Yangtze River is 19℃ to 22℃, and the rainfall is 90mm to110mm. In spring, flower crops should be harvested in time. As the agricultural proverb says, "There are many kinds of seedlings in summer, and Man Cang will reap more millet." Before and after the long summer, it is also the red season for transplanting early rice in the north and south of the Yangtze River.

There is still little precipitation in North China and Northwest China. Coupled with windy and strong evaporation in spring, soil drought often seriously affects the normal growth of crops, especially the influence of dry and hot wind on wheat before and after filling and milk ripening.

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