Why does the application of herbicides cause freezing damage to wheat? How to prevent and remedy?

In the case of frequent cold waves and droughts, improper use of herbicides in wheat fields is prone to freezing injury.

So why does wheat freeze when herbicides are applied? How to prevent and remedy? Today, Bian Xiao will share with you the causes, prevention and remedies of freezing injury caused by herbicide application in wheat. Let's have a look!

Cause of occurrence

Reasons for drug selection In many areas, hypertonic isoproturon and benzene sulfonic acid have been used in wheat fields. Isoproturon and bensulfuron? Isoprotron, chlorosulfonic acid? Isoproturon and other herbicides containing isoproturon.

After the application of these herbicides, the cold wave is easy to cause freezing injury.

Frequent cold waves According to statistics, there were five cold waves from June 20th, 2008 to June 20th, 2009. Such frequent cold wave weather is likely to lead to freezing injury in wheat fields using the above herbicides.

A survey of high-dose and high-concentration liquid medicine was carried out in villages and towns such as Tuojia, Liuhan, Gaoyou and Longqiao. It was found that the dosage of frozen medicine was increased in all the seriously damaged fields, and the dosage of 50% isoproturon was increased to more than 230 grams in some fields, and some fields were mixed with fenoxaprop-p-ethyl.

When the cold wave is frequent, with the increase of dosage, it is inevitable that the wheat field will be frozen.

According to the investigation, water shortage and high concentration of liquid medicine are also one of the reasons for the injury of frozen drugs.

Drought The winter drought in 2008 is also an important cause of freezing injury.

According to the investigation, the wheat field with low soil moisture and dry border surface is seriously damaged by freezing.

In the same field, in a wet place, the damage caused by frozen medicine is relatively light, and the aboveground parts of wheat seedlings do not freeze to death, while in a dry and white place, all the aboveground parts of wheat seedlings freeze to death.

It shows that high humidity in the field has cold resistance and heat preservation effect on wheat seedlings, which can prevent freezing injury.

Agriculture is extensive. Farming is relatively extensive, and no wheat is planted. The root system of wheat seedling is shallow, and the tillering node is not protected by soil layer, so the freezing injury is serious.

Wheat with big seedlings and weak seedlings has relatively strong cold resistance, and vice versa.

Strong seedlings are less harmful, while weak seedlings and diseased seedlings are relatively more harmful.

Freezing injury caused by soil factors mostly occurs in sandy land, but not in clay land.

preventive measure

First of all, according to the weather forecast to determine the appropriate medication period.

The current weather forecast has been relatively accurate, especially the application of satellite cloud images, which can accurately predict the weather situation in the future 1 week.

As long as you pay attention to the weather forecast, you can avoid taking medicine in bad weather.

Secondly, strictly control the dosage of isoproturon, do not arbitrarily increase the dosage, and use enough water.

Thirdly, pay attention to the appropriate soil moisture when using drugs to prevent freezing injury.

Do not use medicine when the soil is dry, which will also affect the efficacy of isoproturon.

If the wheat field is dry, you can add water to moisturize before using the medicine.

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In the wheat field where freezing injury occurs, corresponding measures should be taken to remedy it according to the specific situation.

In the field where the survival rate of tillering node is 70% ~ 80%, fertilizer and water management should be strengthened to promote the recovery of wheat seedlings.

The survival rate of tillering nodes is 30% ~ 40%, especially for wheat with large area soil preparation and sandy soil. The tillering nodes were exposed to the soil surface, so the wheat seedlings could not resume their growth. Therefore, we can consider planting other crops.