The origin of Great Cold Composition is 450 words.

The Great Cold is the last of the twenty-four solar terms, and it is called "Great Cold" when the sun reaches 300 degrees of the yellow meridian around 65438+1October 20th every year. Great cold refers to extremely cold weather. Time-sharing, time-sharing, time-sharing and time-sharing quote three rites and meanings: "Great cold is the middle, shaped by slight cold, so it is called great ... extremely cold, so it is called great cold." At this time, the cold wave frequently goes south, which is the cold period of the year in most parts of China. The wind is strong, the temperature is low, and the snow on the ground does not melt, showing a cold scene of ice and snow.

In ancient China, the Great Cold was divided into three stages: "One stage is chicken milk; Second, the symptoms of bird disease; Three times, the water is strong. " In other words, in the great cold solar terms, chicks can be hatched; Falcons such as eagles are in a state of strong predation ability, hovering in the air to find food to supplement their body energy to resist the cold; In the last five days of the year, the ice in the water has frozen to the center of the water, and it is the strongest and thickest.

During the severe cold solar term, the atmospheric circulation is relatively stable, and the adjustment period of circulation is about 20 days. When this circulation is adjusted, there will often be a wide range of rain and snow weather and strong winds to cool down. When the west of 80 degrees east longitude is a long wave ridge and East Asia is a coastal trough, under the influence of northwest wind flow control and constantly supplemented cold air, China will have a sustained low temperature.

Like slight cold, great cold is also a solar term indicating the degree of cold weather. Modern meteorological observation records show that in some areas of China, severe cold is not as good as slight cold, but in some years and a few coastal areas, the annual minimum temperature will still appear in the severe cold solar terms. Therefore, it is necessary to continue to do a good job in the cold protection of crops, especially to protect livestock from wintering.

For some crops, a proper low temperature is necessary in a certain growth period. Wheat and rape with strong winterness need lower temperature through vernalization stage, otherwise they cannot grow and develop normally. Most parts of southern China are warm all the year round. Wheat and rape sown too early tend to grow too vigorously, jointing and bolting ahead of time, and their cold resistance is greatly weakened, which makes them vulnerable to low temperature frost. It can be seen that selecting crop varieties according to local conditions, sowing and planting in time and taking effective measures to promote and control are important links to win high yield.

Slight cold and severe cold are the periods with the least rainfall in a year. During the cold solar term all the year round, the rainfall in most parts of the south only increased slightly compared with the previous period, with 5 ~10mm in most parts of the south and only1~ 5mm in the mountainous areas of the northwest plateau. During the winter drought and the overwintering of crops in South China, the water consumption is small, and the contradiction between supply and demand of farmland water is generally not prominent. However, "if you are bitter and cold, don't complain about the rain and snow. Snow is reserved for next year's wheat." In the case of scarce rain and snow, it is undoubtedly beneficial to the growth of early spring crops to water in different areas according to different farming habits and conditions.

During this period, the cold wave frequently goes south, which is a rather cold period in most parts of China in a year. Railway, post and telecommunications, petroleum, maritime transportation and other departments should pay special attention to take measures as soon as possible to prevent severe weather such as strong winds and blizzards. Agriculture should strengthen the cold and antifreeze of livestock and wintering crops.