Source: People's Daily
Source: People's Daily
The twenty-four solar terms are a time knowledge system created by Chinese observing the heavens and the earth and recognizing nature, as well as the basic observance of arranging agricultural production and coordinating agricultural activities, and it is also a living system in which Chinese society responds to the times and guides practice, and is a typical representative of the achievements of the Chinese of China's excellent traditional culture. On February 4, 2022, Lichun, the countdown to the opening ceremony of the Beijing Winter Olympics began in the time rotation of the traditional Chinese calendar, and the twenty-four solar terms flashed one by one on the big screen, starting from "rain" and finally marching to "Lichun". Through the 24 solar terms, the countdown is integrated with ancient poetry and contemporary Chinese images full of vitality, and the Chinese rhyme is transmitted to the world.
Twenty-four solar terms
Whether it is the lunar or solar calendar
Cheng Zhuo, an associate researcher at the Purple Mountain Observatory of the Chinese Academy of Sciences, introduced that the calendars produced in the history of human civilization can basically be divided into 3 categories: solar calendar, lunar calendar and luni-solar calendar. Calendars based primarily on the cycle of change of seasons, i.e., the year of regression, are called solar calendars, such as the current Gregorian calendar. The calendar based mainly on the lunar phase yin and sun, that is, the synodic month, is called the lunar calendar. The calendar that takes into account the return year and the synodic month is called the luni-solar calendar, and the traditional Chinese calendar is a typical representative of the luni-solar calendar.
"The lunar calendar is the current traditional calendar on the mainland. According to the national standard "Calculation and Promulgation of the Lunar Calendar" drafted by the Purple Mountain Observatory of the Chinese Academy of Sciences, the New Year is the first lunar day of the lunar month, which means that the first day of each lunar month must be the New Year. Each lunar month reflects the full cycle of moon phase changes and therefore belongs to the lunar part of the luni-solar calendar. The twenty-four solar terms in the lunar calendar reflect the different positions of the Earth in orbit around the Sun, that is, the regression year cycle, and therefore belong to the solar part of the luni-solar calendar. ”
Dr. Zhao Yanan, Director of Agricultural History Research of the Agricultural Museum of China, introduced that as the part of the solar calendar of the lunar calendar, the twenty-four solar terms are also the benchmark for calculating the number nine, summer volt, spring society, autumn society and other time points, such as people are accustomed to counting nine from the winter solstice or the second day of the winter solstice, and the third Geng day after the summer solstice as the beginning of the volt day.
Wang Kechao, director of science popularization at the Purple Mountain Observatory of the Chinese Academy of Sciences, said that it is worth mentioning that the regression year cycle adopted by the Han Dynasty Primeval Calendar was 365.25 days, and the Song Dynasty calendar was more accurate to 365.2425 days, which is the same as the return year cycle of the current Gregorian calendar, but more than 300 years earlier than the exercise time of the Gregorian calendar. For more than 2,000 years, the Chinese calendar has calculated the twenty-four solar terms without interruption. Since the founding of New China, the Astronomical Almanac and Civil Almanacs compiled by the Purple Mountain Observatory of the Chinese Academy of Sciences have also published 24 solar terms every year.
A description of climatic phenology
Whether there is universality
The twenty-four solar terms originated in the Yellow River Basin. Looking at China, which is vast from east to west, with very different climates from south to north, is the description of the twenty-four solar terms universally applicable everywhere?
Han Guirong, chief forecaster of the Jiangsu Meteorological Observatory, introduced that the twenty-four solar terms were originally formulated according to the shift of the bucket to the stars, the Seven Stars of the Big Dipper rotated in a cycle, and the handle rotated clockwise for a cycle, which is called one "year". The current establishment of the twenty-four solar terms is based on the "annual apparent movement of the sun", that is, the solar ecliptic longitude. Although the two establishment methods are different, the reason for the rotation of the stars is that the Earth orbits the sun, so the intersection time between the two is basically the same.
"The twenty-four solar terms characterize the position of the Earth in orbit and the correspondence between the seasons and the climate, and it is very scientific. Since it is science, it is universal. Therefore, the twenty-four solar terms are generally applicable to the Yangtze River Basin of the mainland and even the northern hemisphere, and even the southern hemisphere can learn from its definition and connotation. Han Guirong introduced that taking the first solar terms as an example, it means that everything in the northern hemisphere has begun to recover, which is a trend. Of course, the mainland is vast, the north-south span is large, on the day of "Lichun", Heilongjiang may still be snowing, Hainan Island is already sunny, even in Jiangsu Province there are temperature differences, but the trend of "spring back to the earth, gradually warming" is the same.
Zhu Tianzhong, assistant librarian of the Agricultural History Research Department of the China Agricultural Museum, said that due to the fluctuation of global temperature in thousands of years, especially during the peak and trough periods, some solar terms will become longer, and other solar terms will become shorter, that is, the phenomenon of "expansion and drift" will occur. Therefore, the adaptability of some of the solar terms accumulated in the history of each place will also be affected, but people will correct it according to the specific conditions at that time. In short, in terms of the timing law of climate, phenology and other changes, the twenty-four solar terms have a wide range of adaptability.
For modern agriculture
How instructive
Since the formation of the twenty-four solar terms, it has been a bellwether for agricultural production on the mainland. The times are developing with each passing day, and now that agriculture has gradually bid farewell to the traditional planting mode of watching the sky and eating, how much guiding significance does the twenty-four solar terms still have for today's agricultural production?
The growth and development of crops is inseparable from factors such as light, temperature, gas, heat, and water, and the twenty-four solar terms still have guiding significance for today's agricultural production. Mao Fengwu, deputy director of the Henan Agricultural Technology Extension Station, introduced it.
The spring equinox, summer solstice, autumn equinox, and winter solstice in the twenty-four solar terms are used to indicate the length of day and night; the sting, qingming, small fullness, and mango seeds contain phenological characteristics, which reveal that climatic conditions are constantly changing; rain, valley rain, light snow, and heavy snow indicate the amount of precipitation; small summer, large summer, summer heat, small cold, and large cold indicate changes in temperature. These laws still have certain guiding significance for today's agricultural production, especially the agricultural proverbs related to local agricultural production formed according to the twenty-four solar terms in various places, which are easy to grasp and disseminate, and still play a role in agricultural production. It is embodied in the following aspects:
First, it provides a timescale for modern agricultural sowing and harvesting. The 24 solar terms such as mango seeds, cold dew, and frost fall are of great significance in guiding the sowing and harvesting of crops. For example, mango seeds are the dividing point of the timing of crop cultivation, a time when temperatures rise significantly, rainfall is abundant, and air humidity is high, making it suitable for cereal crops such as late rice. As the agricultural proverb goes, "Mango seeds are planted, busy harvesting and busy planting."
Second, it provides climate projections for modern agricultural field management. Through the general characteristics of temperature, rain and sunshine, the 24 solar terms can provide short-term climate predictions for modern agricultural field management. The winter solstice, for example, represents the coldest time of the year, during which the quality of field management is extremely important for the following year's harvest. Taking Henan wheat as an example, it should be irrigated in advance to protect winter water and ensure that seedlings can safely overwinter.
Third, it provides early warning warning for modern agricultural disaster prevention and mitigation. The combination of the twenty-four solar terms with production experience by working people can reflect to some extent the critical period of disasters. For example, the Qingming festival, the agricultural proverb said, "Before and after the Qingming Dynasty, I am afraid of the evening frost, and I should be on guard when the sky is sunny and there is no wind."
Yu Zhanyao, deputy research librarian of the Agricultural History Research Department of the China Agricultural Museum, introduced that in recent years, the mainland has implemented the strategy of rural revitalization, and the twenty-four solar terms have played a more unique and diversified role in guiding agriculture, forming many agricultural festivals related to solar terms. For example, the state holds the Chinese Farmers' Harvest Festival every autumn equinox, and various forms of harvest celebrations are held in various places. At the same time, traditional festivals and folk customs activities are also very rich, such as the Internet Festival held in Guyu in ZhouGezhuang Village, Jimo District, Qingdao, Shandong, the Frost Festival held in Tianhe County, Guangxi, and the Winter Solstice Festival held in Sanmen County, Zhejiang Province. The integration of festival folklore and farmhouses has also created unique rural tourism projects, which have promoted the integration of agricultural culture and tourism and injected more vitality into the development of modern agriculture. (Reporters Shi Fang, Ma Yuefeng, Yao Xueqing, Tang Zhongke)
People's Daily ( 2022-02-18, 15th edition)