How many leaves of wheat should be weeded? What's

For wheat farmers, they will be busy weeding soon after the emergence of wheat. When it comes to weeding time of wheat, it is customary to judge by the number of wheat leaves.

Normally, when the wheat grows to 3-5 leaves, it is the peak time for wheat weeding, and also the time when most farmers are used to spraying herbicides. However, some farmers think that the 3-5 leaf stage of wheat is too early, which will delay the time of wheat weeding.

From the growth habits of wheat and weeds, combined with the characteristics of herbicides, when the wheat grows to 3-5 leaves, most weeds in the field are 2-4 leaves. From the perspective of wheat itself, its antidote is relatively strong at this time. After herbicide is sprayed on the leaves, it will not easily cause harm.

From the perspective of weeds themselves, the individuals are relatively small at this time, and their own resistance is weak. After absorbing the herbicide solution, they are very vulnerable to damage, and thus achieve the effect of weeding.

From many years of practical planting experience, when the wheat grows to 3-5 leaves, it is the best time to spray herbicides. If the herbicide is sprayed too early or too late, it will cause certain impact.

For example, when the wheat is just emerging and leaves 1-3, when the wheat is just sprouting and exposed, its resistance is very weak. If herbicide is sprayed at this time, there are two effects.

First, farmers use whole field spray when spraying herbicides, which will lead to the absorption of herbicide solution by wheat seedlings. At this time, the antidote of wheat seedlings is weak, and herbicide damage is easy to occur.

Second, during the period when wheat just emerged, weeds in the field also just emerged, and many weeds emerged later than wheat. At this time, herbicides are sprayed after seedling, only with contact effect, but no sealing effect. If weeds do not emerge, they cannot contact the herbicide solution. Most of the herbicides are sprayed to the surface, which cannot achieve the purpose of weeding after seedling. After a few days, there will be a lot of weeds in the field. Therefore, it is not recommended to spray herbicides before 3 leaves of wheat.

When the wheat grows to 5 leaves, spraying herbicides at this time also has two effects.

First, at this time, the resistance of wheat in the field is relatively strong, but the weeds in the field are growing well. The later the herbicide is sprayed, the stronger the resistance of the weeds. Although the probability of the occurrence of chemical damage to wheat is reduced, the control effect of weeds is also reduced.

Secondly, if the wheat has not been sprayed with herbicide after it enters the jointing stage, the little helper will not recommend that you spray herbicide again. The herbicide mentioned above is not used as early as possible. Here, the herbicide is not sprayed as late as possible. Once the wheat enters the jointing stage, it is more sensitive to herbicides, reducing the weeding effect and increasing the probability of wheat damage.

Therefore, it is not recommended to apply herbicides after 5 leaves of wheat. However, with the improvement of land preparation quality, there are relatively few weeds in some plots when the wheat leaves are 3-5, and no weed control was carried out years ago. After the wheat returns to green, the weeds in the field will gradually increase. It is also possible to spray herbicides at this time. However, it should also be noted that once the wheat enters the jointing stage, herbicides should not be used again.

Next, let's extend the question of how to choose wheat herbicides. Weeds in wheat fields can be divided into broad leaf weeds and sharp leaf weeds. The herbicides on the market can also be divided into broad leaf weed herbicides, sharp leaf weed herbicides and herbicides that can be used for both grass and broadleaf.

Common broad-leaved weeds in wheat fields include Artemisia scoparia, Veronica, Shepherd's purse, Sargassum esculenta, Fanzhou, etc. The corresponding broad-leaved weed herbicides in the market include bensulfuron methyl, cloflupyroxyacetic acid, 2 methyl 4 chloride, oxadiazon, difluoroxadiamide, chlorsulfuron methyl, etc.

Common sharp leaf weeds in wheat fields include wild oats, sorghum, broom grass, bromegrass, kentucky bluegrass, Aegilops tauschii, etc. The corresponding herbicides in the market for wheat sharp leaf include acetoxyfop, fenoxaprop-p-ethyl, chlorsulfuron, methyl disulfonate, etc. Among them, methyl disulfonate is a specific herbicide for controlling Jiejie wheat.

Near the end, we will briefly talk about some precautions when weeding wheat, and the remedial measures for accidental harm.

1. After the average temperature of the day is lower than 10 ℃, it is not recommended to spray herbicides. Under low temperature, it will not only reduce the effect of herbicides, but also increase the probability of drug damage.

2. In windy weather, it is not recommended to spray herbicides. In overcast weather, when it is about to rain or drop sharply, it is also not recommended to apply herbicides.

3. For wheat fields with poor wheat emergence, weak growth and yellowing wheat seedlings, herbicide spraying should also be suspended to promote wheat recovery before weeding.

4. Before using the wheat herbicide, it is recommended to dilute it twice, and do not increase the dosage privately. In addition, do not re spray or miss spraying during the use process, so as to improve the weeding effect and avoid the occurrence of drug damage.

If the wheat is harmed by medicine due to human factors or weather factors, farmers should not worry. First, they should spray clean water in time, then spray plant growth regulators such as brassinogen and gibberellin, and at the same time add potassium dihydrogen phosphate to promote the recovery of wheat growth. The more timely the remedy is, the less the wheat is affected by the medicine.

To sum up, the best time for weeding wheat is the 3-5 leaf period. Early or late weeding has more or less influence.

Ask everyone, when did you weed the wheat in previous years?