How to use herbicides in vegetable fields safely? Master these key application points
Weeds in vegetable fields are a major problem in vegetable production. Hand weeding is both labor-intensive and backbreaking, so the vast number of vegetable growers need to use herbicides in vegetable production. However, vegetables come in many varieties, have short growing periods, high multiple-cropping indexes, and complex crop rotations, and there are also many types of herbicides. If used improperly, they can easily cause herbicide damage, or even total crop loss...
Weeds in vegetable fields are a major problem in vegetable production. Hand weeding is both labor-intensive and backbreaking, so the vast number of vegetable growers need to use herbicides in vegetable production. However, vegetables come in many varieties, have short growing periods, high multiple-cropping indexes, and complex crop rotations, and there are also many types of herbicides. If used improperly, they can easily cause herbicide damage, or even total crop loss. Through several years of herbicide trials, demonstrations, and investigative research, I have found that the following points must be observed when using herbicides in vegetable fields:
1. Reasonably select herbicide varieties
There are many herbicide varieties. Different herbicides have different target weeds, and different vegetables have different adaptability to herbicides. Therefore, reasonably selecting herbicides is crucial. According to trials and demonstrations, the following herbicides are safe and low-toxicity for vegetables.
① 48% trifluralin emulsifiable concentrate, 100-150 milliliters per mu, suitable for Chinese cabbage, pak choi, celery, radish, carrot, kidney bean, and cowpea, applied as soil treatment before sowing and before transplanting tomato, pepper, eggplant, cabbage, and cauliflower.
② 25% nitrofen wettable powder 300-400 grams, used for soil treatment before sowing kidney bean, cowpea, carrot, celery, and coriander and before transplanting cucumber, tomato, pepper, and cauliflower. It can also be mixed with 50% prometryn wettable powder 50 grams for a better effect.
③ 50% prometryn wettable powder 200-250 grams per mu, used for soil treatment before sowing celery, old-root Chinese chives, carrot, and coriander.
④ 33% pendimethalin emulsifiable concentrate, 100-150 milliliters per mu, suitable for soil treatment before sowing kidney bean, potato, pea, directly sown Chinese chives, and cruciferous crops and before transplanting solanaceous vegetables.
⑤ 20% napropamide emulsifiable concentrate, 250-300 milliliters per mu, suitable for soil treatment before sowing radish, Chinese cabbage, and kidney bean and before transplanting eggplant, tomato, pepper, cabbage, potato, and watermelon.
2. Improve application quality
The level of herbicide control efficacy on weeds and the timing and quality of application to vegetables are closely related. Therefore, the following issues must be noted:
① Master the application rate. "Two accuracies" must be achieved, namely accurate field area and accurate calculated herbicide amount. In fields with high organic matter content, microorganisms decompose herbicides, and clay adsorbs herbicides, so the application rate for such fields should be appropriately increased. Conversely, for lean fields and sandy fields, the application rate should be reduced as appropriate.
② Master the application timing. Trifluralin, napropamide, nitrofen, prometryn, and pendimethalin are all soil-treatment agents, which mainly take effect through absorption by weed young roots and young shoots, inhibiting weed growth. They are generally applied after crop sowing but before emergence or before transplanting. Quizalofop-p-ethyl is a foliar-treatment agent, which is absorbed into the plant through weed stems and leaves and destroys their meristematic tissues. The appropriate application time is the 3- to 6-leaf stage of grass weeds.
③ Soil-treatment agents must be sprayed after rain or after watering, that is, when soil moisture content is 20%-30%. Except that after spraying trifluralin, soil should be mixed to a depth of 2-3 cm in time to prevent photodegradation, other types of herbicides generally require protecting the soil-surface herbicide film, and mixing soil and trampling should be avoided.
④ Master the water dilution volume for application. Dilute the herbicide with 25-30 kilograms of water per mu, and spray evenly. The sprayer used must not leak, spurt, drip, or spill.
⑤ When using herbicides in solar greenhouses and plastic tunnels, attention should be paid to ventilation at high temperatures to avoid herbicide damage.
⑥ Cucumber, lettuce, and garland chrysanthemum are sensitive to trifluralin and prometryn; celery and carrot are sensitive to napropamide; Chinese chives, Welsh onion, and other Liliaceae vegetables as well as spinach are sensitive to nitrofen, and they are also very sensitive in fields where these herbicides were used on the previous crop. When using them, application and following crops should be avoided. The effect of herbicides in controlling weeds in vegetable fields and their safety to vegetables are closely related to local climate, soil texture, vegetable varieties, and cultivation methods. Therefore, the use of every herbicide should follow the principle of "trial, demonstration, extension" to achieve labor-saving, safe, efficient, and high-yield results.