On August 7th or 8th every year, beginning of autumn is considered as the time when the sun reaches 135. Twenty-four solar terms: "July Festival, set up a word to solve spring (beginning of spring). Autumn is also awkward, and this is the thing. " Beginning of autumn generally indicates that hot summer is coming and autumn is coming. After beginning of autumn, although the summer heat is hard to get rid of for a while, there is still the afterglow of "autumn tiger". beginning of autumn is also called beginning of autumn, but the general trend is that the weather is getting colder and colder. Due to the different climates in different parts of the country, the start time of autumn is also inconsistent. In climatology, autumn begins with the day when the daily average temperature drops steadily below 22℃ every five days. This division method is in line with the local reality, but it is quite different from the date of beginning of autumn in the middle and lower reaches of the Yellow River. After beginning of autumn, early rice harvest, late rice transplanting and autumn crops entered an important growth and development period in central China. Autumn means that summer is cool and autumn begins. The ancients regarded beginning of autumn as an important moment at the turn of summer and autumn, and always attached great importance to this solar term. In ancient China, beginning of autumn was divided into three periods: "A cool breeze blows gently; Second, wait for the white deer to be born; Third-class chilling. " This means that after beginning of autumn, people will feel cool when it is windy, and the wind at this time is different from the hot air in summer; Then, there will be fog on the earth in the morning; And cicadas who feel gloomy and sing in autumn also begin to sing. According to records, the plane tree planted in the basin was moved into the temple by Li Qiuqiu Palace in the Song Dynasty. It's time for "beginning of autumn". Tai Shigong shouted, "Autumn is here." After the play, the phoenix tree dropped one or two leaves to express autumn. In fact, according to the standard of climatic division of seasons, the beginning of autumn is when the average daily temperature drops below 22℃ in the second half of the year. There are few areas in China where "beginning of autumn" falls in autumn, except the summer-free areas which are connected in winter and spring and autumn. Qiu Lai's earliest Heilongjiang and northern Xinjiang will also fall in mid-August. Generally speaking, the autumn wind in the capital Beijing begins to cool down in early September, and the autumn around Qinhuai begins in mid-September. In early June, the autumn wind blew to Lishui, Zhejiang, Nanchang, Jiangxi and Hengyang, Hunan. In the first half of June, the news of autumn reached Leizhou Peninsula, and the footsteps of autumn reached Yaxian County, Hainan, which is the "Tianya Haijiao". It is almost New Year's Day. "It's so hot after autumn", the temperature is still high in most parts of China around beginning of autumn, and all kinds of crops grow vigorously. Mid-season rice blooms and bears fruit, round stems overnight, soybean pods, corn ears, cotton bolls and sweet potato tubers expand rapidly, and the demand for water is very urgent. The drought in this period will cause irreparable damage to the final harvest of crops. Therefore, there are sayings that "the rice turns into rice after three rains in beginning of autumn" and "the autumn rain is falling, and gold is everywhere". Double-night growth is in a high-temperature to low-temperature environment, so we must seize the favorable opportunity of high temperature, topdressing and ploughing to strengthen management. At present, it is also an important period for cotton to protect peaches and catch autumn peaches. "Cotton beginning of autumn, the height is pulled together." In addition to applying quick-acting fertilizer to the fields with poor growth, topping, pruning, removing old leaves and wiping redundant buds should be carried out in time to reduce boll rot and boll dropping and promote normal maturity and boll spitting. Autumn ploughing in tea garden should be carried out as soon as possible. As the agricultural proverb says, "seven gold diggers and eight silver diggers", autumn tillage can eliminate weeds, loosen soil and improve water conservation and storage capacity. If combined with fertilization, autumn shoots can grow better. Before and after beginning of autumn, the northern Chinese cabbage should be sown quickly to ensure sufficient heat conditions before the low temperature comes, and strive for high yield and high quality. Sowing is too late, the growth period is shortened, the growth of vegetable trees is small, and the core is not solid. Beginning of autumn season is also a concentrated period of many crop diseases and insect pests, such as yellow rice borer, rice leafhopper, rice planthopper, cotton bollworm and corn borer. Therefore, it is necessary to strengthen prediction and prevention. The sowing of winter wheat in the north is about to begin, and preparations such as soil preparation and fertilization should be made as soon as possible. Calculation of beginning of autumn date [y * d+c]-Interpretation of L formula: Y= two digits after the number of years, D=0.2422, L= leap year, 2 1 century C=7.5, and 20th century =8.35. For example, the date of beginning of autumn in 2088 = [88× 0.2422+7.5]-[88/4] = 28-22 = 6, and August 6th is beginning of autumn. Exception: The calculation result in 2002 is 1 day.