This year temperatures are on the low side, how should wheat be protected from freezing?
According to the weather forecast, this year is a year with extremely low temperatures, so this winter may be very cold, and therefore extra attention should be paid to protecting wheat from freezing. Take care to help wheat suffer less from the harmful effects brought by the weather. So how should wheat be protected from freezing?
Symptoms of wheat freeze injury:
Winter freeze injury is the freeze injury caused by cold wave cooling after wheat enters winter and during the overwintering period. According to the plant symptom manifestations after wheat is frozen, winter freeze injury can be divided into two categories:
The first category is severe freeze injury, that is, the main stem and large tillers are frozen to death, and the heart leaves dry up, generally occurring in wheat fields that have already jointed. Because wheat has entered the jointing stage, its cold resistance is significantly reduced, and especially the main stem and large tillers, whose development process is earlier than that of small tillers, are most susceptible to damage.
The second category is general freeze injury, with symptoms of yellow-white dry and withered leaves, but the main stem and large tillers are not frozen to death. The first category of freeze injury will affect yield, while the second category of freeze injury basically has no effect on yield.
Measures for protecting wheat from freezing:
1. Choose the right time for winter irrigation
Proper winter irrigation is beneficial for wheat to overwinter safely. Winter irrigation can increase the heat capacity of the soil and at the same time promote the growth and development of wheat seedlings. Strong and robust wheat seedlings are conducive to freezing resistance. At the same time, note that winter irrigation should be done when the temperature is around 4 degrees Celsius. If it is below 4 degrees Celsius, there will be a risk of freeze injury. The result will be the opposite of what is desired. The temperature must be well controlled. Remember: if it only thaws and does not freeze, watering is too early; if it only freezes and does not thaw, it is too late; freezing at night and thawing during the day is just right for watering. That is, before the arrival of cold air and a large temperature drop, carry out one winter irrigation.
2. Control vigorous growth and promote sturdy growth
When freeze injury occurs during the wheat overwintering period, spraying wheat seedlings with a 0.3%-0.5% chlormequat solution or hoeing to cut roots can inhibit plant growth and resist or reduce the occurrence of freeze injury.
3. Fertilization
In early spring, when wheat turns green, promptly spray potassium dihydrogen phosphate as well as humic acid, seaweed acid, and amino acid foliar fertilizers. Spraying potassium dihydrogen phosphate can strengthen roots and seedlings, while humic acid and seaweed acid foliar fertilizers can provide wheat with resistance. At the same time, they can quickly promote the greening of wheat.
4. Sow an appropriate amount
During this year's wheat harvest, seed germination occurred, and the germination rate and germination vigor dropped significantly, so when sowing, the sowing amount can be appropriately increased, but it should not be increased too much. If the sowing amount is too large, the wheat seedlings will be dense and grow tall, making them prone to freeze injury. For the specific sowing amount, it is recommended to ask the local seed dealer and determine it after understanding the germination rate of the variety in detail.
5. Compacting after sowing
It is beneficial for wheat to overwinter. Compacting the soil can close the gaps in the soil, thereby improving the soil's heat preservation capacity. Especially after straw is returned to the field, compacting is even more necessary.
6. Mound soil around the roots
Before overwintering, when the wheat seedlings are about to stop growing, in combination with hoeing, mound soil around the roots. This can effectively prevent wheat from freezing during the overwintering period, and it is especially obvious in years with severe freeze injury, generally increasing yield by 5%-10%.
7. Cover with manure
After wheat enters the overwintering period, spread a layer of manure along the rows (commonly known as “warm furrow manure”), which can avoid wind, preserve moisture, increase temperature, prevent freezing, and supplement nutrients for the greening and growth of wheat seedlings. The suitable thickness of manure cover is 3-4 cm, and about 5 carts of manure are applied per mu. When insufficient, priority for covering should be given to late-sown wheat fields, shallow-sown wheat fields, sandy wheat fields, and wheat fields sown with weakly winter-hardy varieties.
8. Cover with straw
Before winter, spread 300-400 kg per mu of wheat bran, chopped wheat straw, or other plant waste between the wheat rows. This preserves moisture, prevents freezing, and after decomposition can also improve the soil and build up soil fertility. It is an effective measure for wheat to resist drought, prevent freezing, and increase yield.