Analysis of the impact of recent low temperature rain and snow weather on agricultural production

Since mid-December, large-scale winds and snowfall have occurred in China, and winter wheat, rapeseed and open field vegetables have suffered from freezing damage in some areas. At the same time, windy and cool weather has a significant adverse impact on animal husbandry and facility agriculture. The weak snowfall occurred in the southern part of North China and most of Huanghuai, which was conducive to soil growth, but the drought in most areas was not effectively alleviated; precipitation in some parts of the south was too high, which caused the farmland soil to be too wet and affected the normal growth of crops. All localities should strengthen crop field management, and do a good job in cold and anti-freezing of livestock, greenhouses, and economic fruit trees to reduce disaster losses.

The impact of low temperatures, rain, snow and windy weather on agricultural production. Since mid-December, there have been a wide range of low-temperature rain and snow in China. The temperature in most parts of the country has dropped by 5-10 °C, the eastern part of the northwestern region, the central and western Inner Mongolia, Shanxi, Shandong and the western Jianghuai, Jianghan and most of the Jiangnan. The range is 10~14°C, and the local area is 15～17°C. There are 5~6 winds in most parts of the north of Huanghuai and parts of the south of the Yangtze River.

Figure 1 Actual picture of the maximum daily temperature drop in the country (December 12-15, 2010)

At present, winter wheat in Xinjiang, the northwestern part of China, and northern North China have stopped growing into the wintering period. Most of the northern winter wheat areas in northern Xinjiang have more than 5 cm of stable snow cover, which is conducive to winter wheat safely wintering. The minimum temperature in the winter wheat area of ​​most of North China and the eastern part of Huanghuai fell to -15~-5°C, which prompted the winter wheat to stop growing and enter the wintering period normally. The lowest temperature in the western part of Huanghuai and the northern part of Jianghuai fell to -7~-2°C, which was beneficial to winter wheat to resist cold, but some winter wheat with weak seedlings suffered from freezing damage. The lowest temperature in the central and southern Jianghuai, Jianghan, Jiangnan, northern South China, and the southwestern part of the country fell to -4 to 0 °C, causing ice and atrophy in winter wheat and rapeseed leaves in some areas, and cold vegetables such as exposed vegetables, potatoes, sugar cane and flue-cured tobacco. However, due to the short duration of the low temperature, the frozen crops can basically resume growth after the temperature rises.

Since mid-December, weak snowfall has occurred in the central and southeastern parts of the northwestern region, southern North China, and most of the Huanghuai area, which is conducive to soil growth. In some areas, the drought has been moderated to a certain extent, but precipitation is small, North China and Huanghuai. The drought in the region has not been effectively alleviated. The abundant precipitation in the south is conducive to the drought relief in the early drought-stricken areas and the increase of reservoir water storage, but the precipitation in southern Anhui, most of the south of the Yangtze River, northern part of southern China, and southeastern Guizhou is 50-100 mm, southwestern Zhejiang, central Jiangxi, and Hunan. The precipitation in the south, northwestern Fujian and northeastern Guangxi reached more than 100 mm (Fig. 2). The precipitation caused the farmland soil to be over-wet, and some low-lying plots showed water accumulation. The winter wheat and rapeseed roots were affected by waterlogging, and the growth and development were affected. It is not conducive to the formation of strong seedlings; at the same time, the wet and cold weather also significantly reduces the photosynthesis of crops, slows the growth of vegetables, and is prone to disease, affecting yield and quality.

Figure 2 Accumulation of national precipitation (mm) from December 11 to 16, 2010

In addition, the windfall is not conducive to northern animal husbandry activities, affecting livestock grazing, pasture transition, winter lamb production, resulting in livestock feed shortage, high mortality rate of young; northern Xinjiang, northeastern Inner Mongolia, most of the northeast, and central and eastern Jiangnan snow The depth is 10-20 cm, which reduces the temperature and light transmission in the greenhouse, affects the normal growth of vegetables, and easily causes some greenhouses to collapse due to a large amount of snow cover. In addition, the low temperature and snowfall cause the southern fruit trees to be frozen and bamboo. When economic forests are bent and broken, they also affect the safe wintering of poultry, livestock and aquatic products.

Future weather impacts on agricultural production and production recommendations. It is expected that in the next 10 days, the temperature change in most parts of China will be large. From the 17th, the temperature in most areas will rebound significantly, which is conducive to the recovery of frozen crops in the early stage. After 22 days, due to the influence of strong cold air, the temperature in the central and eastern regions will show a significant downward trend, which will reproduce crop growth. Negative Effects.

From 23 to 24, the amount of snowfall (rain) in northern Xinjiang, eastern Inner Mongolia, northeastern region, North China, Huanghuai, eastern Sichuan, and Tibet is generally 1 to 5 mm, which is bound to drought in North China, Huanghuai and northern Jianghuai. The mitigation effect; the precipitation in the eastern part of the Jianghuai, Jiangnan, South China and Southwest China is generally 10 to 25 mm, and some areas in the south of the Yangtze River and northern China are 30 to 60 mm, which will aggravate the soil over-wet condition and is not conducive to crop growth. Suggest:

1. Strengthen crop field management to mitigate adverse weather effects. In the north, wheat fields that are not covered with stable snow cover should be repressed, fertilized and covered to prevent drought and freeze, so as to ensure winter wheat safely. In the southern region, snow in the field should be removed in time, and measures such as cultivating and covering soil and applying wax fertilizer should be taken to increase soil temperature and prevent freezing damage of winter wheat and rapeseed. At the same time, it is necessary to grasp the clearing of the ditch and reduce the soil moisture of the farmland to avoid aggravation of wetness.

2. Do a good job in cold-proof and anti-freezing work such as animal husbandry and facility agriculture. In the northern pastoral areas, it is necessary to strengthen the sheds and barns in a timely manner, coordinate the arrangement and transportation of forage materials, increase reserves, and prepare for disaster prevention and disaster relief in response to the “white disaster”. Greenhouse greenhouses should be repaired and reinforced with scaffolding, and multi-layer covered insulation or artificial heating measures should be used to keep warm and warm. At the same time, snow should be removed from the top of the greenhouse to prevent snow from crushing the greenhouse. The southern region should also pay attention to the cold insulation of vegetables, flowers and fruit trees, and also take effective measures to prevent colds in livestock and aquaculture.