Application technology of herbicides in soybean field

In recent years, the application area of soybean herbicides has increased year by year, and the problems such as poor weeding effect and crop damage caused by man-made reasons often occur in the production. therefore, the application technology of herbicides in soybean field is introduced as follows. First, how to use herbicides scientifically in soybean fields. The suitable herbicide varieties were selected according to the kinds of weeds in crop field. Any variety of herbicide has its own herbicide spectrum, including broad leaf control, narrow leaf control (Gramineae, Cyperaceae), and some narrow leaf and broad leaf weeds, but no matter how good a herbicide is, it is impossible to effectively control all the weeds in the field, so before using herbicides, it is necessary to find out what weeds are in the field and distinguish which are major weeds and which are secondary weeds. Herbicides should be selected according to the principle of main weeds and secondary weeds in the field. For example, it is very effective to control annual broad-leaf weeds such as Chenopodium, amaranth, Polygonum, Xanthium, Elsholtzia splendens, abutilon and Solanum nigrum in soybean field, but perennial broad-leaved weeds such as chicory and thorn in the field are also very effective at the same time. It is not good to use weeds burning and Pushite to control broad-leaved weeds, so we should choose broad-leaved weeds in the field, such as Kuocaoqing, Tian Yi, Guangmianling, Golden sickle and so on. In order to control the field of borage, thorn herb. Therefore, before using herbicides, we must investigate and understand the types of weeds in the field, use targeted drugs, and do not look at what drugs are given by others. Second, soil characteristics determine the dosage and efficacy of soil treatment herbicides. Soil characteristics mainly refer to soil texture, organic matter content, soil moisture and soil preparation quality. For clayey soil and soil with high content of organic matter, the adsorption capacity of colloid (colloidal particles are organic and inorganic fine particles contained in soil) is strong, and herbicides are adsorbed more, so a high amount within the recommended dosage should be used as appropriate to ensure the herbicidal effect; while sandy soil and soil with low organic matter content, their adsorption capacity is weak and easy to leach, and a low amount of recommended dosage should be used as appropriate to avoid drug damage. Good soil moisture is conducive to the desorption of herbicides adsorbed by soil colloids and released in soil solution to be absorbed by weeds; soil moisture is not good, herbicides firmly absorbed by soil colloids can not be released into soil solution to be absorbed by weeds, the weeding effect is poor. Therefore, if the soil moisture is not good and there is no irrigation condition, do not force soil closure to kill weeds, but should be changed to post-seedling stem and leaf treatment. When the soil is closed, the soil preparation quality must be good, and the soil should be leveled and raked fine without big soil bumps, so that a medical film can be formed on the soil surface after spraying, and the weeds will touch the film and die after being unearthed. If the quality of soil preparation is not good, it will affect the formation of the film, thus affecting the effect of weeding. Third, the correct choice of spraying period. When chemical weeding is suitable for soil treatment, it is suitable for soil treatment, and when it is not suitable for soil treatment, it should be treated with stems and leaves after seedlings. Medication must be carried out in a timely manner. Most of the herbicides treated in soil are effective on weed sprouts. If some weeds have been unearthed too late, the weeding effect will not be very good. Generally speaking, the herbicide must be applied within 5 days after sowing. When applying herbicide, the surface of the soil is dry, and the herbicide is easily absorbed by the soil particles. It is necessary to use irrigation and rainfall to leach the herbicide into the 0--5cm soil to exert its efficacy, or to use mechanical mixture to reach the 2--5cm soil to exert its efficacy. The application of herbicides in stems and leaves after seedlings should be appropriate and late, but not too late. Generally speaking, when weeds are applied at 2 murmur3-leaf stage and 2-Murray 4-leaf stage after soybean seedlings, weeds emerge unevenly too early, and weeds need to be re-applied or other weed control measures should be taken after emergence (except for pesticides such as Pushter and isoxanone, which can be used for both soil treatment and stem and leaf treatment. If the herbicide is applied too late, the weeds will be large, the resistance will be strong, and the efficacy will be significantly reduced, and if some herbicides are applied too late, the dosage will have to be increased appropriately, which is not safe for crops. In addition, sometimes in order to catch up with rain during spraying, it is also common to catch up with rain, especially in large-scale production, because different herbicides have different physical and chemical properties and processing dosage forms, there are differences in the interval between spraying and rainfall. We should pay close attention to the local weather forecast before spraying and strive to finish spraying the day before the rain. In this way, weeds can not only fully absorb pesticides, but also accelerate the transmission of agents in weeds, and weeds grow and develop fast and have poor drug resistance after rain, and the weeding effect is good. In general, the efficacy was not affected by rain 0.5 hours after spraying Kekuole, but not affected by rain within 1 hour after spraying with Jing Gao Ke, Jing Jian de, Naopojing, Shoulotong, Jindou and Pushi. Huwei, Bentazon (Paicaodan) and Baocheng did not affect the efficacy 4 hours after spraying, and rain 6 hours after spraying weeds did not affect the efficacy. Fourth, choose appropriate herbicides to avoid the damage of long residual herbicides to the following crops. In recent years, due to the neglect of herbicide soil residual toxicity, the damage of subsequent sensitive crops occurred from time to time, involving rice, vegetables, melons and other crops. At present, the main long-residual herbicides used in soybean fields are Pushite, chlorosulfuron, Guangmianling, Kuocaoqing and so on. Special attention should be paid to their residue dynamics in soil and their safety to different crops. To grow corn, choose land that did not have chlorosulfuron last year. To grow rice (including seedbed soil), you should choose land that did not use chlorosulfuron and chlorosulfuron last year. When planting wheat, we should choose the land where the active ingredient of isoxanone per mu is less than 50g. To grow sugarbeet, we should choose the land where chlorosulfuron and imipramine were not used in the first 4 years, azoxachlor and imipramine were not used in the previous 2 years, and hypertonic fluorosulfonate was not used in the previous year. To grow vegetables (tomato, eggplant, pepper, cabbage, radish), choose the land that has not used chlorosulfuron and imidazuron in the previous 3 years. To grow potatoes, choose land that has not used chlorosulfuron or chlorpyrimidine for 3 years. To grow pumpkins, watermelons, zucchini and cucumbers, choose land that has not used chlorosulfuron and imidazuron in the previous 3 years. In addition, the use of long residual herbicides should be viewed relatively. Some herbicides have good control effects, and the harm of long residual effects can be avoided by changing the application method. For example, Pushte is a long residual herbicide, we only use it for stem and leaf treatment, and when the stem and leaf treatment is mixed with other herbicides similar to the herbicide spectrum, it can also be used by adding spray auxiliaries to reduce the amount of raw drugs or using stem and leaf seedling application to reduce the herbicide entering the soil as much as possible, so that the problem of long residual effect will not occur. Fifth, the scientific mixed use of herbicides and the amount of spray. In order to expand the herbicide spectrum, herbicides should be mixed frequently. The main problem that should be paid attention to in mixed use is that the mixed herbicides should not have antagonistic effect, and if there is antagonism to reduce the drug effect, it is best not to be mixed. For example, 25% golden sickle water agent is effective in the control of duckweed, borage pod, bauhinia, thorn herbicide, etc., but should not be mixed with sulfonylurea herbicides (chlorosulfuron, Baocheng, Baoshou, etc.); if the mixed herbicides have significant synergistic effect, the dosage should be reduced appropriately. If the mixture has neither antagonism nor synergism, the herbicides with different herbicide spectrum are used according to the normal dosage, and the herbicides with the same herbicide spectrum can be halved as appropriate. At present, the main problem in the production of spraying liquid is that under the condition of drought, it is mistakenly believed that the amount of spraying liquid should be increased, and the amount of spraying liquid should be increased from the traditional 150--200L/ hectare to 300--400L/ hectares. in fact, the larger the spraying quantity, the better. It is appropriate to apply 200L/ hectare before seedling. For example, spraying 1000L per hectare is only equivalent to rainfall 0.1mm, which is neither economical nor helpful to exert the efficacy. The amount of spray for the treatment of stems and leaves after seedlings should also not be too large, because if the amount of spray is large, the fog droplets are easy to become big, and if the spray droplets are too large, it is easy to fall from the leaves of weeds and lose their efficacy, and the appropriate amount of spray is about 100--130L/ hectares. when spraying, such as severe soil drought and air relative humidity below 65%, the amount of spray should be added to the stems and leaves after seedlings, 0.5% Rue 1.0% vegetable oil spray aids Xiaobao or Xindebao. It can not only reduce the dosage by 30%, but also obtain stable efficacy.