The occurrence of weeds in wheat field is becoming more and more serious. In the choice of control time, it is better to spray herbicides before the year, which can be conducive to weed control.
There are the following favorable factors to control weeds in wheat fields:
1. Pre-winter weed seedlings are small, poor resistance, drug resistance, less drug use, low cost. According to the data, the cost per acre of chemical weeding before winter is only 2/3 of the cost of conventional drug weeding in spring.
2. Before winter application, the wheat seedling is not sealed, the field closure is small, the weeds grow naked, the spraying area is large, and the control effect is good.
3. The effect of overwintering malignant weeds such as pig seedlings, barley plants and wild oats, especially the grass weeds in wheat fields, is poor in spring, but the effect of removal before winter is good.
4. The unearthed amount of weeds before winter accounts for more than 90% of the total number of weeds, and the unearthed amount in the next year is less than 10%. Overwintering weeds and wheat are unearthed at the same time, competing for nutrients and water.
5. Herbicide before winter, long safety interval, safe for the next crop.
6. Pre-winter application can prevent drug damage to adjacent sensitive crops.
Precautions for weeding wheat fields in winter:
1, wheat spraying herbicide, there is a hard requirement for temperature, should pay attention to the temperature changes in a few days before and after spraying. Some herbicides are more sensitive to temperature, and the effect of weeding is slow when sprayed at low temperatures. If you encounter large temperature drop, rain and snow weather after spraying, it is also prone to drug damage. Generally spraying herbicides, when the daily average temperature is above 5℃ and the temperature changes greatly, the spraying should be stopped. The best temperature for wheat weeding in winter is above 8 ° C on average, remember that it is the average temperature, although some wheat herbicides also have the effect of low temperature resistance, it is recommended to stop application when the minimum temperature is below 0 ° C, so as not to affect the control effect and even drug damage. In contrast to the application in the evening when the temperature is high in summer, the winter wheat field weeding is recommended at noon when the temperature is high, which is more conducive to the drug effect and improve the weed control effect.
2, spraying herbicide years ago, after 3 leaves of wheat, resistance is strong. Before the 3rd leaf stage, the wheat seedling is small and prone to herbicide damage. Generally, after 3 leaf stage, the plots with strong wheat seedling growth should be sprayed with herbicides, which should not cause drug damage. If there are weak yellow seedlings, serious disease seedlings, do not recommend spraying.
3, herbicide should be evenly sprayed, not heavy spray. Some farmers see more weeds, they will spray more, which is also prone to drug damage. When the soil humidity in the field is too large and there is water, herbicides cannot be sprayed, which is prone to drug damage. When there is a strong wind, herbicide should not be sprayed to avoid the drug drifting to other fields.
4, if the conditions for spraying can not be met before the year, that is, when the seedling age is small and the temperature is not up to it, the herbicide should be sprayed after the year, the wheat should be well weeded after this period, when the temperature reaches, the drug should be used as soon as possible to reduce the harm of weeds to wheat.
5. For example, in areas with high resistance of pig seedlings, the mixing effect of difluosulachlor and clofluropyloxyacetic acid is better, and in areas with serious resistance of Artemisia plantaris and shepherd's purse, it is recommended to use dimethyl tetrachloride + difluosulachlor + zoxalone formula.
6, for the grass weeds such as wheat, wild oats, brome and other weeds harm more serious plots, can choose methyl disulfonon and acetylide, azolinoxate for control. It should be noted that the use of methyl disulfonon is prone to drug damage, keratin-type durum wheat and wheat with higher protein content are more sensitive to this, the use of methyl disulfonon needs to be above 8℃, similar to the control of broad-leaved weed herbicides, after application of cooling, frost, rain and snow weather is easy to cause drug damage.
7, the selection of wheat herbicides, especially herbicides containing azoxalone ingredients, can not be more cream pesticides mixed use, must master the correct use of procedures before use - the first two dilution of the agent, the sprayer first with half a bucket of water, the dilution of the good liquid medicine added, fully stirred, the water filled, and then continue to stir evenly.
8, as far as possible to do not heavy spraying does not leak spraying, heavy spraying area is easy to form a heavier drug damage.
9, spraying herbicides in wheat fields, not only depends on the temperature of the day, but also depends on the climate change of at least four days after spraying, and abnormal weather such as cooling, rainfall, snow, or sudden rise in temperature within four days is also the main factor causing herbicide damage.
Winter wheat field weeding precautions
2023 12/04