When is the best time to hit the herbicide after "meat in the field" soybean (soybean) seedling? How to play? What should be paid attention to?

Soybean, also known as soybean, is a common crop in China, which is widely planted because of its high planting prospects, and if you want to have a high yield of soybean, you must do a good job of weeding. When is the best time to hit the herbicide after soybean seedlings? How to play? What should be paid attention to?

First of all, we learn about the common herbicides in soybean fields and what common weeds are in soybean fields. Gramineae has Codonopsis mandshurica, barnyard grass, sargassum grass, dogtail grass and so on. Broad-leaved grass has amaranth, iron amaranth, Xanthium sibiricum, purslane and so on. Of course, quinoa (ash vegetable), spinach, field twirl, duck foot grass are also indispensable.

Weeding time after seedling:

After emergence, the control was carried out at the stage of 1-3 compound leaves and 2-5-leaf weeds of soybean, while the best application period of herbicides after seedling was 3-5-leaf stage of barnyardgrass and 2-4-leaf stage of broad-leaved weeds (general plant height was about 5 cm). It is difficult to control duckfoot grass before 3 leaves and after 3 leaves. When the pesticide is applied too early, the weeds emerge unevenly, and the weeds can not be killed without contact with the pesticide. When the pesticide is applied too late, the resistance of soybean is weakened, the resistance to weeds is enhanced, and the control is more difficult, so it is necessary to increase the dosage, which not only increases the cost, but also easily causes drug damage.

Types of herbicides:

Generally for isoxazone, prednisone, fluorosulfen, trifluorocarboxylate, ethyl carboxyfluoxane and other agents, single or compound, there are safe and conventional ones on the market, and the price is different. When weeding, choose the appropriate herbicide according to the situation.

What kind of medicine should I use?

To control Gramineae weeds, use 5% quizalofop EC 60ml / mu, or 50ml / mu with 15% EC, 30ml / mu with 10.8% efficient EC, or 50ml / mu with 6.9% Weiba concentrate, or spray 80ml / mu with 12.5% EC and spray 20kg of water.

To control broad-leaf weeds, use 25% Huwei, Longwei, fluorosulfonate and other water agents per mu, or use 44% grams of atrazine water agent 8 ml, or use 24% weed incinerator 4 ml 6 ml, spray 2 kg of water.

Note:

Note: what is a soybean compound leaf, that is, there are three leaves on a petiole as a compound leaf. Soybean reaching three such compound leaves is called triple leaf stage! The time of use of herbicides on soybeans is also important not to use herbicides after heavy rain or when there is more dew.

Factors affecting the efficacy of herbicides:

1. Grass age: the effect of grass age on soybean herbicides is self-evident. When buying herbicides, the salesperson will also tell you to use the herbicides at the 2-4 leaf stage of weeds, because when it is too early, the weeds have not yet come out, and the herbicides after seedlings have no sealing effect, and they will continue to grow weeds, and they will find that there are still many weeds in the follow-up fields, while weeding is too late, weed resistance is enhanced, and it is not easy to control weeds. If the dosage is increased, soybean is easy to cause drug damage, so, after research, when weeds have 2-4 leaves, pesticide application is the best time.

2. Temperature: temperature plays a very important role in any crop when using herbicides. For soybeans, the suitable temperature for herbicides is 15-25 degrees Celsius. If the temperature is too low, below 13 degrees, or too high, above 30 degrees, medication is not recommended. Because the temperature is too low, the metabolism of soybean slows down, the sensitivity to herbicides increases, the resistance is weak, and it is prone to drug damage, and if the temperature is too high, it will lead to the evaporation of the liquid too fast, and the ability of weeds to absorb the solution will also be reduced. both of them will weaken the efficacy of herbicides and fail to achieve the purpose of weeding. So in the higher temperature weather, it is recommended to choose before 10:00 in the morning, after 15:00 in the afternoon.

3. Humidity: the quality of soil moisture in the field also has a very important influence on the efficacy of herbicides. If the field is too dry, weeds will close some of their stomata for their own growth and prevent water from evaporating too fast. Under such a premise, if you hit the herbicide, the amount of the liquid absorbed by the weeds is very small, which can not play the effect of weeding. So do not hit the herbicide in the case of drought, you can carry out irrigation, or by other means, spray it after the soil moisture is better.