What are the seasonal characteristics of October?
Every year1October 8 or 9, when the sun reaches longitude 195, it is cold dew. "Twenty-four solar terms" said: "In September, the dew is cold and will condense." Cold dew means that the temperature is lower than that of the white dew, and the dew on the ground is colder and will soon condense into frost. In the cold dew season, Nanling and the vast area to the north have entered autumn, and the northeast and northwest regions have entered or are about to enter winter. In the capital Beijing, you can see the first frost in many years. In addition to the perennial snow on the Qinghai-Tibet Plateau, it has generally begun to snow in the northeast and northern Xinjiang.
After the cold dew, the cold air in the north has a certain influence, and most parts of China are controlled by cold high pressure, and the rainy season is over. The weather is often warm during the day and cool at night, with clear skies and Wan Li, which is very beneficial to the autumn harvest. Thunderstorms have disappeared in most parts of Chinese mainland, and only Yunnan, Sichuan and Guizhou can hear thunder. The precipitation in June 5438+ 10 in North China is generally only half or less than that in September, while in Northwest China it is only a few millimeters to more than 20 millimeters. Drought and lack of rain often bring difficulties to timely sowing of winter wheat and become one of the main limiting factors for high yield of dry land wheat.
At this time, it is still autumn rain in Hainan and Southwest China, and rainy weather will also occur in Jianghuai and Jiangnan in a few years, which will have a certain impact on autumn harvest and autumn planting.
"Cold dew doesn't pick cotton, and first frost doesn't complain." . When the weather is good, we should pay close attention to harvesting cotton. When the temperature drops early, we can take it back when the temperature is not too low. One-season late rice is about to mature in Jianghuai and Jiangnan, and double-season late rice is filling. Pay attention to intermittent irrigation to keep the fields moist. The southern rice areas should also pay attention to prevent the harm of "cold dew wind". North China should hurry to sow wheat. At this time, in case of drought and little rain, we should try our best to accumulate soil moisture, grab soil moisture for sowing, and ensure that sowing is completed before and after the first frost. We must not passively wait for rain to lead to planting early crops and late wheat. Before and after the cold dew is the suitable sowing date for direct seeding rape in the Yangtze River basin, and the variety arrangement should be that Gan Lan-type varieties should be sown first, and then cabbage-type varieties should be sown. Those who sow green manure in the south of Huaihe River should be cleaned up, and those who have emerged should be cleaned and drained to prevent waterlogging. The tuber swelling of sweet potato in North China Plain gradually stopped, and the probability that the morning temperature was lower than 10℃ or lower gradually increased. According to the weather conditions, we should pay close attention to harvesting and strive to finish it before the first frost, otherwise potato tubers will "harden their hearts" because they are frozen underground for too long, reducing the value of eating, feeding and industrial utilization, and cannot be stored or used as seeds.
The solar term of the first frost is1October 23rd or 24th every year, 10. According to the "Twenty-four solar terms": "In mid-September, the gas is cold and condensed, and the dew is like frost." It can be seen that the first frost refers to the beginning of frost. However, China has a vast territory, and the climate varies greatly from place to place. "The first frost in the first frost" reflects the climate characteristics of the Yellow River Basin. As far as the annual frost days are concerned, there are frost and snow in some parts of the Qinghai-Tibet Plateau even in summer, and the annual frost days are over 200, which is the place with the largest number of frost days in China. The annual frost days in eastern Tibet, southern Qinghai, Qilian Mountains, western Sichuan Plateau, northwestern Yunnan, Tianshan Mountains, Altai Mountains, western mountainous areas of northern Xinjiang, northeast China and eastern Inner Mongolia all exceed 100 days, and the vast areas south of Huaihe River, Hanshui River and east of Dongpo of Qinghai-Tibet Plateau are all below 50 days, with only the annual frost days in the south of 25 north latitude, Sichuan Basin, south of Fuzhou and coastal areas of Guangdong and Guangxi being/kl.
The appearance of frost shows that the lowest ground temperature has reached below 0℃, which will have a certain impact on crops. The first frost in autumn is called the first frost. The earlier the first frost, the greater the harm to crops. The first frost in all parts of China is gradually delayed from north to south and from mountainous areas to plains. Except for areas with frost all the year round, frost first appeared in the north of Daxing 'anling, usually at the end of August. The first frost in most parts of Northeast China, Inner Mongolia and Northern Xinjiang is mostly in September. 10 Frost has appeared in Shenyang, Chengde, Yulin, Qamdo and Lhasa. 165438+1Frost has been seen in Shandong Peninsula, Zhengzhou, Xi 'an and northwest Yunnan in early October; Frost did not appear in eastern China, Hanshui and Yunnan provinces until the beginning of 65438+February. First frost from Xiamen and Guangzhou to Baise and Simao is 65438+1early October after the New Year.
In the first frost season, the cool autumn wind blew to Guangzhou, the flower city. The average temperature in the northeast, eastern Inner Mongolia and most of the northwest has been below 0℃, the soil has frozen, and the winter crops have stopped growing and entered the wintering period. For soybean harvest in North China, spring varieties should be selected for late wheat that has not been sown, and seedlings should be checked and replanted for those that have emerged. The Yangtze river basin is in the golden season of winter wheat sowing. Rape has generally entered the two-leaf stage, so it is necessary to sow in time, weed in intertillage and control aphids. Late-maturing rape that has not been planted due to floods in disaster areas can be sown with wet ash manure first, and then sown indoors to accelerate the emergence of seedlings. "If the first frost doesn't harvest the crops, it will lose a reed one day." When the late rice is ripe, we should pay close attention to harvesting to prevent birds from damaging the seeds. The Chinese cabbage in North China is about to be harvested, so it is necessary to strengthen the later management.
In the first frost season, most parts of China enter the dry season, so we should attach great importance to forest protection and fire prevention.