Different varieties of herbicides have their own characteristics, such as selectivity, herbicidal range, absorption and transmission and grass killing principles. Practice has proved that the long-term use of one or the same type of herbicide in one place, the resistance of weeds is gradually increased, the weed community in the farmland changes, and the difficulty of chemical herbicides is improved. For this reason, a dosage form in which two or more herbicides are used in combination has been widely used in production. The advantages are as follows:
1. The mixing effect of herbicides
(1) Expanding the scope of grass killing: There are many kinds of weeds in the farmland, broadleaf weeds and monocotyledon weeds, 1 year old and perennial weeds, often mixed and growing, and each herbicide has a certain range of grass killing, so The herbicides with different selectivity and different action sites are scientifically mixed, and the herbicide is obviously enlarged.
(2) Prolonged application of the drug: After the herbicide is mixed, the application period can be extended.
(3) Reducing residual toxicity: After reasonable mixing of herbicides, the residual toxicity is small, the residual effect period is short, and the crops are safe.
(4) Improve the herbicidal effect: After the herbicide is reasonably mixed, it has obvious synergistic effect.
(5) The effect of increasing yield is obvious: after the herbicides are scientifically mixed, the herbicidal effect is obvious, and the crops are safe and the yield increase is obvious.
2, the principle of mixed herbicides
For the mixed use of herbicides, scientific matching should be carried out according to the characteristics of herbicides, weed species and crop types, and some compatibility tests should be carried out. Only when the physical and chemical properties and herbicidal effects are excellent, the mixed use can be determined.
(1) Mixed principle
First, the mixture must have synergistic or additive effects, and has physical and chemical compatibility, no precipitation, stratification and condensation, and no inhibition or phytotoxicity to crops.
Second, the herbicidal spectrum of mixed single agents should be different to increase the site of action and expand the range of herbicides, but the period of use and the method of application must be consistent.
The third is to combine the characteristics of quick-acting and slow-acting, combining the contact type with the systemic type, combining the long-lasting period with the short-lasting period, combining the large diffusivity and the small diffusion in the soil, and the crops. The absorption sites are combined differently.
Fourth, the combination of herbicides and their respective dosages should be determined according to factors such as field weed community, species, occurrence degree, soil texture, organic matter content, crop types, and crop growth period. The mixed amount of herbicide should be single. 1/2-1/3 of the dosage of the agent must not exceed the single dosage on the same crop to achieve economic, safe and effective purposes.
The effect of mixed herbicides is affected by many factors. When using a large area of ​​mixed materials, the small area test should be carried out under different conditions according to different ratios to obtain reliable herbicidal effects and phytotoxicity data to determine the optimal ratio. And after the herbicidal effect is stable, it will be promoted for large-area applications.
(2) Common herbicide mixed varieties: According to the principle of mixed herbicides, it is generally processed directly from the factory into a variety of preparations.
(3) Herbicides are mixed with insecticides and chemical fertilizers: herbicides are mixed with insecticides, plant growth regulators, fertilizers, etc., and are generally used now and are not suitable for long-term release.
A. Mixture of herbicides and insecticides: Some herbicides are mixed with insecticides to have synergistic effects. Such as the combination of carbaryl, acesulfame and enemy, the herbicidal effect of the enemy is significantly improved.
B. Mixing of herbicides and plant growth agents: When some herbicides are added to plant growth regulators, the herbicidal activity is significantly improved. Such as glyphosate and defoligent
C. Mixing herbicides with chemical fertilizers: Mixing herbicides with chemical fertilizers can improve efficiency, reduce costs, and increase production.
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