Will there be a cold spring in 2022? What is the omen? How should crops be prevented? Answer in one article!
After beginning of spring, the weather turned warmer, and everything recovered and was full of vitality.
After entering the spring, we often hear the topic of "late spring cold", which is mainly caused by long-term rainy weather or frequent invasion of cold air, or under the control of cold anticyclone, the strong radiation cooling in sunny nights is more frequent in spring.
So will there be a cold spring in 2022? What are the signs of late spring cold? How should crops prevent late spring cold? The following small series will answer for you.
What is a cold spring?
Late spring cold generally refers to the phenomenon that the temperature rises rapidly in early spring, but it is lower in late spring when the temperature is normal.
In terms of time, after the vernal equinox in March, the temperature rose sharply in some years, and suddenly cold air went south, or under the control of cold high pressure, there was a phenomenon that the temperature was low due to strong radiation cooling on the ground on a clear night.
Late spring cold is a concept used in agrometeorology, because in April and May of late spring cold, the wheat in the Yellow River basin is in the green period, and the temperature drop will cause cold damage to crops. If the average temperature at this stage (usually April-May) is more than 2 degrees lower than normal, it is considered as severe cold weather in late spring.
In fact, to put it simply, in the process of heating up in spring, the temperature drops obviously because of the invasion of cold air, which is harmful to crops. This kind of "warm before spring, cold after spring" weather is called late spring cold.
Agrometeorological experiments show that the average daily temperature is less than12℃ and the maintenance period is more than 3 days, which is not conducive to seedling growth.
If the cooling is accompanied by rainy weather, the harm is even greater, which is a relatively recognized indicator.
In southern China, the spring sowing time comes first and then comes, and the period and intensity index of the cold spring are also slightly different.
Will there be a cold spring in 2022? What is the omen?
Recently, the rain and snow in the south will continue, wet and cold. On the contrary, the weather in the north will be fine and the temperature will rise obviously, but there will also be a wide range of rain and snow in the north. It was very cold this spring, the coldest in recent years.
In fact, there is a greater possibility of a cold spring in 2022. According to the news released by the meteorological department, La Nina incident has been formed, which has affected the frequent cold air in China and has a strong force. The temperature in the central and eastern regions is mainly cold, and there is a greater possibility of extreme cold wave events.
China is a typical country with monsoon climate. March and April are the time when the wind direction in winter changes to the summer monsoon, so it is often attacked by cold air, and it is more prone to late spring cold.
In fact, the Yellow River basin is most affected by the cold in late spring, and the temperature is relatively low in winter. In terms of time, cold air comes early and goes late, which means that winter is too long and may be postponed, which may lead to lower temperature and cold weather in beginning of spring solar terms than in previous years. This probability is very high.
The omen of late spring cold is that it is warm and cold at first, and sometimes it is colder than winter.
Because spring is the transitional season from winter to summer, the summer monsoon in the high-pressure area slowly advances from the sea to the land, and the two cold and warm air masses, winter monsoon and summer monsoon, control each other, with frequent cyclone activities and changeable weather.
If it continues to be cold in spring, we should pay attention to cold protection and warmth according to the weather changes, and increase or decrease clothes in a timely and moderate manner, which can follow the law of "spring covering".
How to prevent crops from getting cold in late spring?
In fact, the late spring cold is harmful to the growth of crops in spring. If protective measures are not taken in time, many crops will reduce production or even freeze to death. Even if they survive, the output and quality will be seriously reduced.
For the northern rural areas, the late spring cold will freeze wheat, cotton, peanuts and vegetables, which has a great impact on the growth of crops.
For southern rural areas, the appearance of late spring cold will lead to the rot of rice seeds and seedlings, delay sowing and affect the normal growth of rice.
First, early rice seedling protection
There are two main ways to plant early rice, one is to sow directly in the field, the other is to raise seedlings in a small field first, and then transplant the seedlings into the field.
In case of late spring cold, the early rice is still in the stage of seedling raising. Before the cooling and strong convective weather come, the greenhouse film for early rice seedling raising should be strengthened, and the dual-mode heat preservation and seedling protection can be covered in conditional areas; At the same time, properly spraying phosphate fertilizer before cooling to enhance the stress resistance of rice seedlings and prevent cold air from causing rice seeds to rot.
Direct seeding early rice should take defensive measures according to local conditions, and those that have not been soaked should be postponed to avoid rotten seeds and seedlings caused by low temperature and rainy weather; Rice seeds that have been soaked to accelerate germination and have not yet been put into the field should be thinned and aired, and should be sown in time after the weather improves; Drainage of sown paddy fields should be strengthened to prevent root rot and bud rot caused by long-term flooding; Paddy fields that have emerged should be properly watered to protect seedlings during low temperature and rainy weather.
Second, wheat prevention.
Wheat is affected by the phenomenon of late spring cold, mainly because the sowing date of wheat is too early; Secondly, because of the poor cold resistance of wheat in the process of growth and development.
Therefore, the main measure to prevent the growth of wheat from being affected by late spring cold is to improve the cold resistance of wheat itself.
For example, cultivating cold-resistant wheat varieties; Greenhouse heating in spring is a very effective method.
On the other hand, from the point of view of growth and development, it is also a very effective measure to prevent the low temperature weather of wheat planting in late spring by appropriately sowing late, delaying the start time of wheat growth and development and perfectly staggering the time difference with the low temperature weather in late spring.
Third, vegetable prevention.
1, low temperature hardening seedlings.
After the seedlings come out, the seedbed should be ventilated. With the warming of the weather, the ventilation rate should be gradually increased, and the seedlings should be exercised at low temperature to improve their cold resistance and adapt to the outdoor low temperature environment.
2. Increase protective facilities.
There are two ways: first, erect a wind wall to block cold air and prevent the surface from further cooling; Second, furrow planting, covering with plastic film, etc. , increase the heat preservation and incubation of seedbeds and vegetable fields.
3. Temporary heating.
When the cold current comes, we can build a simple coal stove or install electric lights for temporary heating in the seedling shed or production shed to raise the temperature in the shed and prevent freezing injury.
4, the right amount of water.
Before frost occurs, spraying water on the surface of plants with a sprayer can slow down the body temperature of plants, increase the frost resistance of plants, increase the content of water vapor in the atmosphere, release the heat of condensation of water vapor, and reduce freezing damage.
Fourth, fruit tree prevention.
1. water.
In orchards prone to late spring cold and with irrigation conditions, water should be poured 1 ~ 2 times before and after germination to reduce the temperature of orchards, postpone germination and avoid late spring cold.
2. Spray salt water.
Pay attention to the weather forecast, spray 10% ~ 15% salt water on the trees before the low-temperature freezing injury comes to increase the concentration of cell fluid in the trees to prevent freezing injury; The heat release of water vapor condensation can reduce the freezing injury of trees.
3. It's smoking.
When the cold current comes, smoke in the orchard as soon as possible: it is best to smoke at night when the temperature drops to 0℃.
6 ~ 7 dry branches and weeds are piled up per mu, and some soil is pressed after burning to improve the smoking effect.
Step 4 spray fertilizer.
Spraying 0.2% ~ 0.3% potassium dihydrogen phosphate aqueous solution on budding fruit trees before freezing injury can increase the cold resistance of the trees, thus reducing the freezing injury.
Generally speaking, there is a great possibility of late spring cold in 2022, so farmers need to collect weather forecasts in time and take corresponding measures to prevent cold and freeze.
In the process of planting crops, drought resistance and frost resistance have always been a very important aspect. If prevention and management are not done well, it is likely to lead to crop failure and affect farmers' planting efficiency and daily life, so it is necessary to take precautions against late spring cold.