Climatic characteristics of Tomb-Sweeping Day gas

Qingming is a solar term representing phenology, which means sunny weather and lush vegetation. As the saying goes, "Qingming breaks snow, Grain Rain breaks frost." When the weather is clear, the climate in South China is warm and the spring is strong. However, before and after Tomb-Sweeping Day, cold air still invaded from time to time, even making the average daily temperature lower than 12℃ for more than three consecutive days, resulting in rotten seedlings of middle rice and dead seedlings of early rice. Therefore, it is necessary to avoid warm tail and cold head when sowing and transplanting rice. In the northwest plateau, livestock are weak under the influence of severe winter and insufficient forage, so it is necessary to guard against the harm of strong cooling weather after spring to old, weak and young livestock. "There are many rains during the Qingming Festival" is a portrayal of the spring rain in the south of the Yangtze River by Du Mu, a famous poet in the Tang Dynasty. But in some areas, this is not the case. Especially in the western part of South China, it is often in the spring drought period, and the rainfall in early April is generally only 10 to 20 mm, which is less than half of that in the south of the Yangtze River. Although there are many spring rains in eastern South China, the rainfall in early April is generally only 20 to 40 mm, so natural precipitation is not enough for agricultural production, so it must be replenished by storing water years ago. In addition, May-June is the month with the most hail in a year, so the prevention of hail disaster should be strengthened. During the Qingming period, the average daily temperature in most parts of the country has risen to above 12℃ except the northeast and northwest regions. From north to south to the inside and outside of the Great Wall, there are busy scenes of spring ploughing everywhere. "In the Qingming Festival, the wheat grows for three days", the wheat in the south of Huanghuai is about to start heading, the rape has blossomed, and the wheat in the northeast and northwest regions has also entered the jointing stage. In the later stage, we should pay close attention to fertilizer and water management and pest control. Dry farming in the north, early and middle rice in the south of the Yangtze River is in a suitable season for mass sowing, so we should seize the opportunity, seize the sunny day and sow early. Pear blossoms are getting clearer and clearer. At this time, when many kinds of fruit trees enter the flowering stage, attention should be paid to artificial pollination to improve the fruit setting rate. Early rice planting in South China should be cleaned up and fertilized in time. Corn, sorghum and cotton will also be planted everywhere. "Before tomorrow's tea, there will be two buds", and the new buds of tea trees will grow vigorously, so attention should be paid to pest control; Famous tea producing areas are mined one after another, and strict scientific mining is needed to ensure the yield and quality.