There are grasses and broad-leaved weeds in the wheat field. How to use herbicides with good results?

Sowing for more than 40 days in most winter wheat planting areas in China is the best time for chemical weeding. So when gramineous and broad-leaved weeds appear in wheat fields, how to use herbicides is the best? With this question, let's talk about weeding management in wheat fields today.

First, how to choose herbicides for weeding in wheat fields?

The selection of herbicides in wheat field is a key factor related to our weeding. There are many kinds of weeds in wheat field, so different herbicides should be selected for different weeds. Such as Aegilops tauschii, Aegilops tauschii, oats, broadleaf weeds such as Descendants, shepherds, shepherds, shepherds and shepherds have different herbicides.

At the same time, the span and difference of winter wheat planting areas in China are also relatively large, and the temperature, humidity and farming methods in each area are different, resulting in different grass phases in wheat fields.

Northern areas: For example, Hebei, Shandong and other northern areas, the weeds are mainly Aegilops tauschii, Bromus, Wild Oats, Descurainia sophia and Capsella bursa-pastoris. For Bromus and Oats, you can choose sulfuron-methyl or fenoxaprop-p-ethyl, and for Descurainia sophia and shepherd's purse, you can choose sodium carbon tetrachloride, tribenuron-methyl, 2,4-di-isooctyl ester or fomesafen. Because there is Aegilops tauschii, methyl disulfonate should be added. South China: In southern China, such as Jiangsu and Anhui, weeds in wheat fields are mainly wild oats, milkweed, Japanese milkweed, hard grass, sedge, chickweed and erigeron breviscapus. For these weeds, we can choose fenoxaprop-p-ethyl or fenoxaprop-p-ethyl plus fluroxypyr and fomesafen for control. 2. Is weeding in wheat field better before or after the year?

Many farmers don't know whether weeding in wheat fields is better before or after the year. Personally, I think it is better to weed years ago. There are several reasons:

The effect of chemical weeding was good years ago: because the weed plants were still young before winter, the resistance to herbicides was weak, and the wheat was not closed before winter, the herbicide liquid could directly contact the surface of weeds, but after the year, the pesticide content of weeds would be significantly reduced because of the closure of wheat. Low cost of weeding before winter: Because weeds are tender and effective before winter, weeds can be removed according to normal pesticide dosage. Weeding after overwintering, because weeds have grown up and have strong drug resistance, the normal dosage of weeding may not achieve the ideal effect. At the same time, some may need to use pesticides for weeding many times, so the cost is relatively high. Weeding before winter is safer: because herbicides themselves have a certain impact on the growth of wheat, the less herbicides are used before winter, the less the impact will definitely be. Weeding after the year is not good for the next crop: if the application time is late, it will affect the normal growth of the next crop. Therefore, based on the above factors, I think the effect of weeding before winter should take precedence over weeding after the year.

Third, matters needing attention in weeding in wheat fields

Weeding before winter should mainly include the following items:

1, seedling age and grass period of wheat

Chemical weeding can only be carried out after 40 days of wheat sowing. Before weeding, we should look at the seedling age of wheat. Due to the different depth of sowing, the emergence time is also different. For wheat with late emergence, see if the goal of three leaves and one heart has been achieved. If not, the weeding time should be postponed to avoid phytotoxicity; In addition, it depends on the grass period of weeds in wheat field, and different weeds should choose different herbicides. If there are many broad-leaved weeds, we should choose herbicides with broad-leaved weeds as the main ones, and vice versa.

2. Pay attention to the temperature when weeding.

When weeding in winter, low temperature weeding is very easy to cause phytotoxicity, so the minimum temperature should not be lower than 2 degrees and the average temperature should not be lower than 5 degrees. If it is Aegilops tauschii, the average temperature should not be lower than 8 degrees, and the best temperature should be above 10 degrees. You can choose to spray at noon on sunny days (165438+ between 0 am and 2 pm). Large growers can choose to spray drugs between 10 and 3 pm.

In recent days, the temperature began to drop, with an average of five or six degrees. The lowest temperature in some areas has reached below zero, and chemical weeding cannot be carried out in this weather.

Wheat herbicide is very sensitive to low temperature, especially methyl disulfonate used to control Aegilops tauschii, which can easily cause wheat phytotoxicity at low temperature. Because of the strict requirements on the use environment of methyl disulfonate, the average temperature should be above 10℃ when spraying, and there will be no obvious cooling or rain and snow weather for three days.

3, pay attention to the dosage and water consumption

Weeding in winter must be strictly in accordance with the herbicide instructions and water quantity, and remember not to blindly increase the dosage. In addition, secondary dilution is necessary.

In short, when choosing herbicides, we should choose herbicides according to the types of weeds in wheat fields, and we should not blindly use drugs. In addition, farmers must choose the spraying date according to the requirements of chemical herbicides and weather forecast. If there is no suitable weather for spraying before, chemical weeding can be carried out after turning green in.