How to correctly use herbicides in forest nurseries?
Can herbicides be used when growing Schisandra chinensis? Will they cause phytotoxicity? 1. Soil residual phytotoxicity 1. Symptoms. In the middle of the growth period, the leaves wilt, and in the morning and evening the leaves recover and become upright, the plant becomes stunted and stops growing, similar to drought, and the root system develops slowly. 2. Causes. The phytotoxicity of triazine, sulfonylurea, imidazolinone, etc....
How are herbicides used in forest nurseries? How can they be used well?Controlling weeds in nurseries has long been a difficult problem in forestry nursery production. Weeds grow rapidly, not only competing with seedlings for nutrients and water, but also serving as intermediate hosts for many pests and diseases. At present, the methods for controlling weeds are manual pulling, cultivation, plastic film mulching, etc., while the simplest and most effective method is to use chemical herbicides.
1. Mechanism of use
1. According to the different herbicide resistance of seedlings and weeds, herbicides can be selected that can control weeds without causing harm to seedlings, and different seedlings react differently to the same herbicide. Some seedlings can use their own enzyme systems to convert harmful substances in herbicides into non-toxic substances, thereby avoiding harm.
2. According to the differences in morphological structure between seedlings and weeds, the main manifestation is the difference in root distribution. Under normal circumstances, seedling roots are distributed relatively deep, while weed roots are mostly distributed in the surface layer of the soil; secondly, it is manifested in the differences between monocotyledonous and dicotyledonous plants and the differences in the distribution of aboveground parts, mainly the height difference between the aboveground parts of seedlings and weeds. Herbicides can be applied selectively to achieve the purpose of controlling weeds and protecting seedlings.
3. According to the different growth times of seedlings and weeds, pre-emergence herbicides or post-emergence herbicides can be selected at the appropriate time.
2. Methods of use
1. For nurseries preparing to take cuttings or transplant young seedlings, use pre-emergence herbicides or soil disinfectants, such as potassium permanganate and prometryn, with a dosage of 50-80 milliliters per 667 sq m, which can effectively control weeds from harming seedlings during one growing season.
2. For large seedlings in the growing period, broad-spectrum herbicides can be used for directed spraying. For example, when there are many dicotyledonous weeds in the nursery, 10.8% haloxyfop-R-methyl EC + 23.5% oxyfluorfen EC can be mixed at 1:1, which can effectively control annual monocotyledonous and dicotyledonous weeds and has no effect on seedling growth. When annual grass weeds grow to 3-4 leaves, use 10% quizalofop-p-ethyl EC 40-50 milliliters per 667 sq m, or 5% quizalofop-p-tefuryl EC 40-50 milliliters, diluted with 50 kilograms of water for spraying. When applying the pesticide, strictly control the dosage, and do not spray the solution on the leaf parts of the seedlings to prevent phytotoxicity.
3. In autumn, for plots where seedlings have already been lifted from the nursery, non-selective herbicides and soil disinfectants can be used for spraying. Such as glyphosate and Nongminle, and deep plowing should be carried out to achieve the dual purpose of controlling weeds and pests and diseases.
3. Precautions
1. Herbicides should be applied strictly according to the seedling species, the different growth stages of the seedlings, and the type of herbicide, so as to avoid phytotoxicity.
2. Herbicides should be applied on sunny days without wind. The higher the temperature, the faster the herbicide takes effect. It is not suitable to apply the pesticide in strong wind, fog, or when there are dew drops on the leaves.
3. Low soil moisture is not conducive to the effectiveness of herbicides. Irrigation can be carried out after application to ensure efficacy.
4. In the early stage of weed growth, the resistance to the pesticide is weak, the dosage is small, and the effect is good, while in the later stage of weed growth, the dosage is large and the effect is poor. Therefore, weed control should focus on controlling them when small, early, and completely.
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