Introduction and application of herbicide products in soybean field

Herbicide in soybean field is an essential product for weeding in soybean field, which has very good control effect on all kinds of weeds. In this paper, the common herbicide products in soybean field were introduced, and their application methods were explained in detail. Details are as follows:

Main weed species and their occurrence regularity in soybean field

Weeds in soybean fields can be divided into three categories, namely annual gramineous weeds, annual broadleaf weeds and perennial weeds. Common main weed species are:

Annual gramineous weeds: mainly barnyard grass, green bristlegrass, golden bristlegrass, wild millet, crabgrass and wild oats.

Annual broad-leaved weeds: mainly Grifola frondosa (Grifola frondosa), Xanthium sibiricum, Amaranthus retroflexus, Solanum nigrum (black star), cauliflower, Amaranthus ferruginea, Elsholtzia Elsholtzia (wild perilla), spinosad, Rambo grass (Polygonum sibiricum), Rumex sibiricum, Commelina communis (L.

Perennial weeds: mainly equisetum arvense (Ajuga), sonchus oleraceus, Cirsium japonicum (Sargassum), reed, etc.

The soybean field was overgrown with weeds from sowing to early August. Weeds in early spring were dominant from sowing to the end of May, and weeds in late spring were dominant from the beginning of June. In recent years, broad-leaved weeds such as Commelina communis, Rambo grass, Polygonum hydropiper, Xanthium sibiricum, Solanum nigrum, Saussurea involucrata, Pogostemon Pogostemonis, Cirsium japonicum and Cirsium japonicum have gradually replaced gramineous weeds such as barnyard grass, wild oats and Setaria viridis. Cirsium japonicum, chicory and Commelina communis, which are called "three dishes", have become the difficulties in weed control in soybean fields.

Introduction of herbicide products in soybean field

Common herbicides before seedling in soybean field

Acetochlor (50% acetochlor, 90% acetochlor, 90% saint-farmer, 90% hennessy)

Acetochlor is generally used for soil treatment and can be used before sowing or before sowing. It is best to apply the pesticide 3-5 days after sowing and before emergence. It should be noted that the application of pesticides in the soil arching period of soybean will cause phytotoxicity, especially in the case of mixing with broad-leaved weeds, and the application of pesticides in the soil arching period of soybean may lead to a decrease in yield. The dosage of herbicide for soil sealing should be adjusted according to soil type and organic matter content.

Chlorsulfuron (bissulfuron, bissulfuron)

Chlorsulfuron can be used before and after soybean seedling, but it is easy to cause phytotoxicity after seedling, so it is generally not recommended. Usually used for soil treatment after sowing and before emergence of soybean, 60-75g of 20% chlorimuron-ethyl is used per hectare, 3-5 days after sowing and before emergence of soybean. Chlorsulfuron-methyl is mainly used to control broad-leaved weeds in soybean fields, and can control weeds such as Xanthium sibiricum, Lamb grass, ferret petals, Perilla frutescens, Polygonum cuspidatum and Chenopodium album. It has inhibitory effect on Cirsium japonicum, Polygonum hydropiper, Potamogeton crispus and Gramineae weeds, but it has poor efficacy on Stellaria, Commelina communis and Solanum nigrum.

Azithromycin (Seck, Dimethylhydrazine)

Generally speaking, soil treatment with azithromycin is carried out 3-5 days before soybean emergence. Atrazine is mainly used to control broad-leaved weeds such as amaranth, ragweed, Chenopodium album, Polygonum hydropiper, chickweed and xanthium sibiricum.

Isoxazole (Wanmiling, Tian, Doucaoling)

The clomazone can be used for closed weeding of soybean before and after sowing, and can also be used for early stem and leaf treatment after sowing. It can control annual gramineous weeds and broad-leaved weeds, such as barnyard grass, green bristlegrass, crabgrass, green bristlegrass, Solanum nigrum, Elsholtzia, Oxytropis, Portulaca oleracea, abutilon, wild watermelon seedlings, Chenopodium album, Xanthium sibiricum, Rambo grass, etc. Effective on perennial weeds such as Cirsium japonicum, Cirsium japonicum and Chicory.

Glyphosate (Agricultural University, Klinda, Haolida, Nongminle)

It is suitable for weed control in early spring in newly reclaimed land and other plots with more perennial weeds. Spraying glyphosate 2-3 days before the emergence of soybean after the weeds are in full bloom can control the perennial weeds that have been unearthed, which can not only achieve the purpose of effectively controlling weeds, but also have strong absorption and conduction, which can kill the underground parts of plants, thus reducing the harm in the next year.

Common herbicides after seedling in soybean field

Huwei (fomesafen) is a herbicide for controlling broad-leaved weeds, which has a wide weed control spectrum. After the application of pesticide, contact drug spots will appear on soybean leaves, which is a normal phenomenon and has no obvious influence on soybean growth, and new leaves will not be harmed by drugs. It is worth noting that in recent years, when corn was planted in the soybean field after the use of Huwei, serious residual phytotoxicity appeared. When using huwei, you must not overdo it and strictly control it within the recommended dose range. It needs to be mixed with gramineous weed herbicides.

Bentazon is a herbicide for controlling broad-leaved weeds, which has a wide weed control spectrum, has special effects on Xanthium sibiricum and is safe for soybean. It needs to be mixed with gramineous weed herbicides.

Burning grass (tribenuron-methyl) is a kind of herbicide for controlling broad-leaved weeds, which has a wide weed control spectrum. After applying the pesticide, soybean leaves will appear contact poison spots, which are slightly heavier than those produced by Huwei. It is a normal phenomenon, which has no obvious influence on soybean growth and will not cause phytotoxicity to new leaves. It needs to be mixed with gramineous weed herbicides.

Ruflufenpropathrin is a broad-spectrum herbicide for controlling broad-leaved weeds. After the application of pesticide, soybean leaves will appear contact poison spots, which are slightly more serious than weed burning. It is a normal phenomenon, which has no obvious influence on soybean growth and will not cause phytotoxicity to new leaves. It needs to be mixed with gramineous weed herbicides.

The five herbicides, Nabujing (Bisultap), chlorhexidine (ketene), propafenone (propafenone), high-efficiency gaifen (propafenone) and propafenone (quizalofop-ethyl), are all herbicides for controlling gramineous weeds, and the weeding effect is similar. When controlling perennial gramineous weeds, high dose or double dose is needed.

How to use herbicides scientifically in soybean field

(1) Select the appropriate herbicide varieties according to the types of weeds in farmland. Any herbicide has a certain weeding spectrum, including broadleaf herbicides, narrow-leaf herbicides (Gramineae, Cyperaceae), and some narrow-leaf herbicides and broadleaf herbicides. However, no matter how good the herbicide is, it is impossible to effectively control all weeds in the field. Therefore, before using herbicides, we must find out which weeds are in the field and distinguish which are the main weeds and which are the secondary weeds.

The selection of herbicides follows the principle of controlling the main weeds and the secondary weeds. For example, annual broad-leaved weeds such as Chenopodium album, amaranth, Polygonum hydropiper, Xanthium sibiricum, Perilla frutescens, sweet potato, Solanum nigrum and so on. It is very effective in soybean field, but at the same time, perennial broadleaf weeds such as sonchus sonchifolia and sonchus sonchifolia are also very common. It is impossible to control broadleaf weeds by burning grass and decomposing, so broadleaf weeds should be selected. Therefore, before using herbicides, we must investigate and understand the types of weeds in the field and use drugs in a targeted manner. Don't look at what medicine people are using, just look at what medicine they are using.

(2) Soil characteristics determine the dosage and efficacy of herbicides in soil treatment. Soil characteristics mainly refer to soil texture, organic matter content, soil water content and soil preparation quality. Cohesive soil and soil with high organic matter content have strong adsorption ability to colloid (colloid particles are organic and inorganic fine particles contained in soil) and absorb many herbicides, so high dosage within the recommended dosage range should be used as appropriate to ensure weeding effect; However, sandy soil and soil with low organic matter content have weak adsorption capacity and are easy to leach, so low recommended dosage should be used as appropriate to avoid phytotoxicity.

Good soil moisture is conducive to the desorption of herbicides adsorbed by soil colloids and their release into soil solution to be absorbed by weeds; The soil moisture is not good, and the herbicide firmly adsorbed by soil colloid can not be released into the soil solution and absorbed by weeds, so the weeding effect is poor. Therefore, if the soil moisture is not good and there is no irrigation condition, it is not necessary to forcibly seal the soil to kill grass, but to treat the stems and leaves after seedling emergence.

When collecting soil, the quality of soil preparation must be good, and the rake should be flat and fine, so that a film can be formed on the soil surface after spraying, and weeds will die when they contact the film. If the quality of soil preparation is not good, it will affect the formation of drug film, thus affecting the weeding effect.

(3) Correct selection of spraying period. When chemical weeding is carried out, the soil should be treated when it is suitable, and the stems and leaves after seedling should be treated when it is not suitable. We must seize the opportunity to take medicine in time. Most herbicides used in soil treatment are effective on weed buds. If some weeds are unearthed too late, the weeding effect will not be very good. Generally speaking, herbicides must be applied within 3-5 days after sowing. When applying pesticides, the soil surface is dry and herbicides are easily adsorbed by soil particles. It is necessary to use irrigation and rainfall to leach herbicides into 0-5 cm soil to exert their efficacy, or to use mechanical soil mixing to achieve 2-5 cm soil to exert their efficacy. Herbicide should be applied late after seedling, but not too late. Generally speaking, it should be applied at 2-3 leaf stage and 2-4 leaf stage after soybean seedling stage. If the weeds are applied too early, the emergence of weeds will be uneven, and the weeds after emergence need to be applied again or other weeding measures (except pesticides that can be used for soil treatment and stem and leaf treatment, such as Pust and clomazone). If the herbicide is applied too late, the weeds will flourish and the efficacy will be obviously reduced. Moreover, if some herbicides are applied too late, the dosage must be increased accordingly, which is not safe for crops.

In addition, spraying pesticides sometimes catches up with rain, especially in large-scale production. Because of the different physical and chemical properties and processing dosage forms of different herbicides, the interval between spraying pesticides and rain is also different. Therefore, we should pay close attention to the local weather forecast before spraying pesticides and strive to finish spraying one day before rain. In this way, weeds can not only fully absorb chemicals, but also accelerate the conduction of chemicals in weeds after absorbing chemicals. After rain, weeds grow fast, have poor drug resistance and have good weeding effect. In general, it is not affected by rain for 0.5 hours after application, but for 1 hour after application, for 4 hours after application and for 6 hours after application.

(4) Choose suitable herbicides for the crops before and after, so as to avoid the damage of long-acting herbicides to the crops after. In recent years, due to ignoring the residual toxicity of herbicides in soil, sensitive crops in the following crops have been harmed from time to time, involving rice, vegetables, melons and other crops. At present, the long-residue herbicides used in soybean fields mainly include Prost, chlorimuron-ethyl, clomazone, broadleaf grass and so on. Therefore, we should pay special attention to its residue dynamics in soil and its safety to subsequent crops.

To plant corn, you should choose the land that has not been covered with chlorimuron-ethyl in the previous year. Planting rice (including seedbed soil) should choose the land that has not used imazethapyr and chlorimuron-ethyl in the previous year. When planting wheat, it is necessary to choose land with no more than 50g of effective components of clomazone per mu. When planting sugar beet, we should choose the land that has not used chlorimuron-ethyl and imazethapyr in the first four years, azosulfuron-ethyl and imazethapyr in the first two years, and high permeability fomesafen in the last year. Planting vegetables (tomato, eggplant, pepper, cabbage, radish) should choose the land that has not used chlorimuron-ethyl and imazethapyr in the previous three years. Choose a place where you haven't used imazethapyr and chlorimuron-ethyl for 3 years to grow potatoes. When planting pumpkins, watermelons, zucchini and cucumbers, you should choose places where chlorimuron-ethyl and imazethapyr have not been used in the previous three years.

In addition, the use of long-residue herbicides should also be treated relatively. Some herbicides have good control effect, and the harm of long residual effect can be avoided by changing the application method. For example, Pust is a kind of herbicide with long residue, so we only use it for stem and leaf treatment, and the stem and leaf treatment is half mixed with other herbicides with similar weed control spectrum. We can also reduce the dosage of the original drug by adding spray additives or try to use the method of applying herbicide with stem and leaf seedlings to reduce the herbicide entering the soil, so that there will be no problem of long residual effect.

(5) The scientific mixing of herbicides and the dosage of spraying liquid. In order to expand the weed control spectrum, herbicides should be mixed frequently. The main problem that should be paid attention to when mixing is that several herbicides cannot have antagonistic effect. If they are antagonistic and reduce the efficacy, it is best not to mix them. For example, 25% aqueous solution of golden sickle has good control effect on Commelina communis, chicory, equisetum arvense and Echinococcus japonicus, but it can't be mixed with sulfonylurea herbicides (chlorimuron-ethyl, baocheng, baoqu, etc.). ); If the mixed drugs have significant synergistic effect, the dosage should be appropriately reduced as appropriate; If the mixture has neither antagonistic effect nor synergistic effect, herbicides with different weed control spectra should be used according to the normal dosage, and herbicides with the same weed control spectrum can be used in half as appropriate.

At present, the main problem in production is to increase the spraying amount under drought conditions, and the spraying amount is increased from the traditional 150-200 L/ha to 300-400 L/ha. In fact, the spraying amount is not as large as possible, and 200 L/ha before seedling is appropriate, such as spraying 1000L/ha. Don't spray too much after the post-treatment of stem and leaf seedlings, because if the spraying amount is large, the fog drops will be easy to be large, and if the fog drops are too large, the liquid medicine will easily roll down from the leaves of weeds and lose its efficacy. The spraying amount is about 100- 130 L/ha. When the soil is seriously dry and the air relative humidity is lower than 65%, the spraying amount should be 0.5.