Main causes and remedial measures of wheat freezing damage

In recent years, due to changes in climatic conditions, wheat freeze damage has occurred, which has affected wheat production to varying degrees. Freezing damage refers to the phenomenon that the cell tissue of wheat is frozen and damaged at a low temperature below 0 °C.

First, the main cause of wheat freezing damage

1. Poor quality of land preparation

Due to the large area of ​​wheat straw returning to the field, and the low cost of rotary tillage and land preparation, some farmers have used rotary tillage for many years, resulting in extensive land preparation and loose soil. Especially when the soil is soiled, the soil cracks are large. Wheat seedlings are extremely susceptible to freezing.

2. improper selection of varieties

The cold resistance of the selected varieties is poor, and it is easy to suffer from freezing damage when the winter cold wave comes suddenly with sudden temperature changes or continuous low temperature weather. For example, in 2004, the weak spring varieties such as Yumai 34 and Zhengmai 9023 were planted in our city. Due to the high temperature before winter, some wheat fields were prolonged or even knotted. After the winter solstice, strong cooling and snowfall occurred and the duration was longer. Long, leading to large-scale freezing damage. According to statistics, the frozen area of ​​wheat in the city reached 71,733 hm2.

3. The broadcast amount is not reasonable

Sowing early will cause wheat to grow long before winter. If the planting is too late and the amount of sowing is too large, it will form a single-stalk seedling and weak seedling without any tiller. The cold-resistant ability is poor and it is vulnerable to freezing damage.

4. Sowing too deep

The best sowing depth of wheat is 3~4cm. When the sowing is too deep, the wheat is weak after emergence. If the seeding is too shallow, the soil is less than 3cm. The tillering section is in a cold and warm environment, and it is easy to cause freezing damage.

5. Watering is not timely

The soil was in poor condition and was not watered in time before the cold current.

Second, the remedial measures after the occurrence of wheat freeze damage

1. Strengthen fertilizer and water management

For the wheat fields where the main stem and the large tillers have frozen, the nitrogen fertilizer should be applied in time to promote the rapid growth of small tillers. After thawing in the field, 10 kg of urea is applied per 667 m2, and dredging is required. Watering should be carried out in time after fertilization in wheat field; 15 kg of urea per 667 m2 combined with watering in wheat jointing stage. Generally, in the frozen wheat field, only the leaves are frozen and dead, and there is no dead cockroach. In early spring, it should be timely slashed, the ground temperature should be raised, the wheat seedlings should be promoted to green, and the topdressing and watering should be carried out during the rising period to increase the tillering rate.

2. Do a good job of foliar spray

Spraying potassium dihydrogen phosphate aqueous solution on the heavily damaged plots to promote the robustness and stability of the straw, and provide a guarantee for the stable growth of wheat.

3. Grasp the prevention and control of pests and diseases

Increase the prevention and control of pests and diseases, and timely control the pests and diseases such as wheat midge, aphids and scab.

4. Interplanting other crops as appropriate

For crops with serious damage and insufficient population, cotton, corn, vegetables and other crops may be interplanted as appropriate to compensate for the losses caused by insufficient spikes.