Application of chemical herbicides after soybean seedlings

Soybean post-emergence herbicide weeding is the continuation and development of pre-emergence herbicide weeding. It has the characteristics of high herbicidal rate, energy saving, convenient use, strong safety and little impact on the crops. Commonly used post-emergence chemical herbicides have the ability to cover grass, stabilize the kill, take the net, Huwei, grass, and bentazon.
(1) Post-emergence herbicide herbicidal effect The herbicidal effect of post-emergence herbicide is closely related to the density of weeds, grass age, species, temperature and humidity. 〖1〗 With weed density, grass age and species relationship Bean field weed density is small, grass age is small and the time of unearthing is concentrated, the selected herbicide and weed community are opposite, the grass killing effect is good; poor effect. 〖2〗 Relationship with temperature and humidity When temperature and humidity turn high, weeds have strong ability to absorb drugs. The agent has great activity in weeds, and the effect of drug is fast, and the effect of killing grass is good; otherwise, the effect of killing grass is low. Relationship between 〖3〗 and Bean Coverage Beans When the soybean plants are short, the leaves are small, and the weeds are small, the grass and beans have a small coverage and the grass killing effect is good; on the contrary, the pea sprouts are large and the weeds are more The grass and the beans have a large coverage, and some weeds are not exposed to the medicine when spraying, and the effect is poor.
(2) Application technology of post-emergence herbicide: 〖1〗 Spraying time After 2 leaves of soybean, the weeds are suitable for 2 to 4 weeks. 〖2〗 How to use There are three ways to use post-emergence herbicides, because the appropriate application method is selected according to the type of weeds in the bean field. Weed species are relatively simple, and should be selected in a targeted manner, used alone; there are many types of weeds, should choose to kill different weeds, mixed application; for mixed application of herbicides that will cause phytotoxicity, should be separated by a certain time , alternate use.
(3) Commonly used post-emergence herbicides: 〖1〗 Huwei is a 25% water agent. The control object is broadleaf grass. The recommended dosage per hectare is 1 to 1.25 liters of Huwei water, 300 to 400 liters of water, and 0.1% to 0.2% of washing powder. Matters needing attention: a, rain after 4 to 6 hours after spraying has no effect on the efficacy. b. The drug has a long residual period, and the dosage should not be too large, otherwise it will cause phytotoxicity to the later crops. c, do not mix with the stable, grass grass mixed use, if necessary, can be used interchangeably, otherwise it is prone to phytotoxicity. d, Huwei will have slight phytotoxicity on soybean leaf surface, and it can resume growth after one week without affecting the yield. e. Please check the instructions before use. If surfactant has been added, no detergent is needed, otherwise it will cause phytotoxicity. 〖2〗 Bentazon is a 25% aqueous solution, a 48% aqueous solution or a 50% wettable powder. Control objects are broadleaf weeds and sedge weeds. The recommended dosage is 48 to 3 liters of 48% flexazone water per hectare, 300 to 400 liters of water, and 0.1% to 0.2% detergent powder. Precautions; a, this drug has a poor effect on the comfrey. b. Can not be used in combination with stable killing, grass, and catching, but can be applied separately. c. When the weather is high, the soil moisture is high, and the weed seedlings grow vigorously, the drug effect is good. d. Re-spray in case of rain within 8 hours of application. e. Pay attention to safety and prevent the liquid from splashing on the skin and eyes. If it is contaminated, rinse it with water immediately. 〖3〗 Take the net for the content of 20% emulsifiable concentrate and 12.5% ​​of the oil emulsion. The control object is an annual grass weed, and a large number can also prevent perennial grass weeds, reeds, and white stalks. The recommended dosage is 20% per hectare or 12.5% ​​oil emulsion, 1 to 1.5 liters, 300-400 ml water, and 3 to 5 leaf stage in grass weeds. Matters needing attention: a, bean field broadleaf weeds for a long time, can be mixed with herbicides to control broadleaf weeds, but can not be mixed with bentazon, weeds, can only be applied separately. b. Prevent the pesticide from drifting to nearby grass crops. c. Do not pour the remaining liquid into paddy fields, lakes or rivers. Wash the instrument after spraying. 〖4〗 The grass can be 12.5% ​​emulsifiable. It can prevent annual and perennial grass weeds. The recommended amount per hectare is 0.75 to 1 liter, 300 to 400 liters of water, and sprayed at the 3 to 5 leaf stage of grass weeds. Note: a, can be mixed with some agents to control broadleaf weeds. b. This medicine exerts a quick effect and it rains 2 hours after spraying, which has no effect on the efficacy. c. This medicine is toxic to fish and should be used when using. e. Avoid splashing liquid or contaminated skin. If accidental contact, rinse immediately with water. 〖5〗 Huwei and cover grass can be mixed with the recommended dosage of 25% per hectare of Huwei water agent 1.25 liters and 12.5% ​​grass emulsifiable concentrate 0.75 ~ 1 liter, 300 to 400 liters of water, 2 to 4 leaves of broadleaf weeds During the period, the annual grass weeds were sprayed at the 3~5 leaf stage. The mixed agent can simultaneously control broadleaf and annual grass weeds. The precautions are the same as the two herbicides used alone.
In addition, the above herbicides may also be alternately sprayed before and after. If the first spray, Hu Wei, interval 1 to 2 days spray to catch net or grass grams; first spray benzene dasong, one day after a spray to catch net or grass grams.
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