After entering the winter, the growth of crops and weeds is relatively slow, but relatively, weeds grow faster and grow faster than crops. Therefore, it is necessary to carry out chemical weeding on winter crops. However, when the herbicide is used at low temperatures in winter, the effect is not as obvious as the season of high summer and autumn temperatures, and sometimes it will not be seen in a short period of time. The main reason is that the herbicide is used on the one hand under low temperature conditions. The effect release is worse. On the other hand, the weed ability of the weeds is also reduced, and the medicament is slowly absorbed and decomposed by the weeds, so that the effect is reduced or even completely ineffective. Therefore, the use of herbicides at low temperatures, in addition to the choice of herbicides on the road, technically should also master the following points.
1. It is not conducive to the exertion of the efficacy of the drug in the winter when the weather is cold, which is not conducive to the effect of the drug. Therefore, it should be applied during the period when the temperature is relatively high. At this time, the physiological metabolism of weeds is relatively strong, which is conducive to the conduction of the agent in the weeds, the metabolic decomposition is difficult, and it is easy to receive a good herbicidal effect. For example, after entering December, weeds are used to control weeds in wheat fields. It is basically difficult to kill weeds, especially herbicides such as isoproturon. When the temperature is too low, they should not be used. It should be postponed until the end of February or 3 When the temperature rises at the beginning of the month, according to the growth of weeds in the field, appropriate herbicides are used to prevent them.
2 The application should be thoughtful and evenly used in the high temperature period in winter. Some weeds are blocked by growth and finally dead, but low-temperature weeding has no such effect, and we cannot rely on the pesticide to kill the weeds. Therefore, the application of the drug should be strictly in accordance with the dilution factor, and the amount of water should not be reduced at will. When spraying, pay attention to thoroughness, no heavy spray, no leakage, and all herbicides should be sprayed with herbicides.
3. It is necessary to have certain patience to use herbicides during low temperature seasons in winter, and the display time of the efficacy is obviously longer than that of the herbicides used in high temperature seasons. For example, rapeseed fields and vegetable fields can be used to control bluegrass, and general farmland needs 12 The phenomenon of grass dryness will occur in -15 days, and the foxtail grass that is used to control farmland in the high temperature stage in summer will generally die within 5-7 days. Therefore, you should wait patiently after taking the medicine. As long as the timing is well grasped, the liquid medicine is sprayed into place and generally does not need to be re-medicated.
4. Choose a variety of methods of use Some herbicides are mixed with soil to make toxic soil, or mixed with fertilizer to make poisonous fertilizers. It is safe to use at low temperatures in winter, and the efficacy is also stable. If you use oatmeal enemy, you can mix 500g oats with 50kg of fine soil, sand or 7.5kg of urea or 15kg of superphosphate. Spray a small amount of water when mixing, so that the medicine and soil or fertilizer are fully mixed. Immediately after the application, the ground is smashed, and the soil or fertilizer is thoroughly mixed with the soil to improve the herbicidal effect.
5. Adding nitrogen fertilizer to improve herbicidal effect When using 2,4-D sodium salt in wheat field, ammonium nitrate, ammonium sulfate and urea are mixed, which can significantly improve the herbicidal effect of 2,4-D sodium salt. Because the addition of chemical fertilizer reduces the tension and pH of the surface of the solution, the adhesion of the pesticide is enhanced, thereby improving the herbicidal performance of the herbicide.
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