What is the best time to weed wheat before winter?

After wheat seedlings emerge, an important part of pre-winter management is weeding . Farmers all know that there are two key periods for weeding winter wheat, one before winter and the other after spring . So, when is the best time to apply wheat herbicides before winter?

Pre-winter weeding (mid-to-late November)

Post-seedling weeding should be carried out when the wheat seedlings have grown to 3 leaves and 1 heart . At this time, the weeds have just emerged from the ground, and the herbicide is most effective.

Because the effect of herbicides is closely related to the temperature, special attention should be paid to temperature changes when weeding before winter. When the temperature is below 5℃, do not apply herbicides ! Otherwise, if the temperature is too low, not only will the herbicide be ineffective, but it will also easily cause herbicide damage.

For pre-winter weeding of wheat, we should apply herbicides on sunny days with no wind and suitable temperature. The best time to apply herbicides is after 9 am and before 4 pm , as the herbicides are easily absorbed by weeds during this period and the weed control effect is better.

Post-spring weeding (late February to early March)

  Post-spring weeding is generally done after the beginning of spring, when wheat enters the greening stage and before the jointing stage . During this period, wheat and weeds will resume growth after wintering. Weeding at this time can kill weeds between ridges and allow wheat to grow quickly.

However, since weeds are larger after spring and the amount of pesticides used is high, some weeds are not easy to kill and the weed control effect may be poor. In addition, it is forbidden to use herbicides when wheat is jointing, otherwise it will cause pesticide damage, affect the normal growth of wheat, and lead to reduced wheat production.

Comparing weeding before winter and weeding after spring, the effect of weeding before winter is better than that after spring. This is because the weeds before winter have just grown out of the ground, the weeds are smaller, and the resistance to pesticides is poor. Spraying herbicides at this time saves medicine and money, and the effect is good.

Therefore, if farmers can weed before winter, they should seize the favorable opportunity and apply herbicides in time when the wheat seedlings emerge and grow to 3 leaves and 1 heart .

How to judge winter wheat with 3 leaves and 1 heart

The 3-leaf 1-heart stage of wheat generally refers to the period after the wheat seedlings emerge, when the seedlings grow 3 complete leaves and 1 heart leaf (which has not yet unfolded).

Under normal circumstances, it takes about 7 days for wheat sown at the right time to germinate. Usually, it takes about 10 days from germination to 2 leaves and 1 heart, and about 7 days from 2 hearts and 1 leaf to 3 leaves and 1 heart. Therefore, 25-30 days after sowing winter wheat is the most suitable time to carry out pre-winter wheat weeding .