Winter herbicides are also incompatible or absent pesticide products . Herbicides are excellent in removing weeds, but if you want to maximize the efficacy of herbicides, you need to master the correct method of herbicide use . The small series for you to analyze it in detail.
First, the principle of selectivity of herbicides
Lawns and weeds occur at the same time, and most weeds and turfgrasses belong to higher plants. Therefore, herbicides are required to have special selectivity or selectivity by proper use, so that they can be safely and effectively applied to the lawn. The selectivity principle of herbicides is as follows.
1. Difference and time difference selectivity
Displacement selectivity means that some herbicides are highly toxic to the lawn. When applying, the selectivity of weeds and lawns in the soil or spatial position can be used to obtain selectivity; time difference selectivity refers to the toxicity to the lawn. Herbicide , the selectivity formed by the difference between turf and weed germination and morning and evening emergence.
2. Morphological selectivity
The selectivity obtained by using the morphological differences between the turf and the weeds is called morphological selectivity. The shape of the plant leaves, the structure of the leaf surface, and the location of the growth point are directly related to the attachment and absorption of the liquid, so these differences often affect the resistance of the plant. For example, monocots and dicots are very different in morphology from each other. With herbicide sprays, dicots are more sensitive to agents than monocots.
3. Physiological selectivity
The selectivity due to differences in the absorption and transport of herbicides by stems or leaves of plants is called physiological selectivity. Plants that are easily absorbed and transported with herbicides are often sensitive to herbicides.
4. Biochemical selectivity
The selectivity due to differences in biochemical reactions of herbicides in plants is called biochemical selectivity. This selectivity is safe in turf applications and is a true selectivity for herbicides.
5. Use protective substances or safeners to obtain selectivity
Some herbicides are less selective and can be selectively selected using a protective substance such as activated carbon or a safener (NA).
Second, the use of herbicides
Soil treatment method
The application of the herbicide to the soil is referred to as soil treatment. According to different treatment periods, it can be divided into soil treatment before sowing, soil treatment before sowing, and soil treatment after seedling.
(1) Soil treatment before sowing The crops are treated with herbicides before sowing or transplanting. The specific application methods can be divided into the following two types. 1 Soil surface treatment before sowing: The herbicide is applied to the soil surface before planting. For example, flowers, turf, vegetables, etc. are applied to control weeds such as metolachlor before transplanting. 2 Mixing soil before sowing: The herbicide is applied to the soil surface before planting, and the method of uniformly mixing into the shallow soil layer is called pre-sowing mixed soil treatment.
(2) Soil treatment before sowing The soil is treated after the crop has not been planted after sowing, and the soil treatment before sowing or the soil treatment before seedling is called. Most soil treatments are applied by this method, including the replacement of important herbicides such as ureas, triazines and amides.
(3) Post-emergence soil treatment The turf growth period is treated with soil or flower transplanting and slow seedling treatment, which is called post-emergence soil treatment. For example, after the flower is transplanted, the weeds have not been unearthed or applied at the seedling stage, such as butachlor or chlorpyrifos. In order to avoid the adhesion of the agent to the plant, granules or agents are often mixed with the wet soil to avoid phytotoxicity.
2. Stem and leaf treatment
The method of spraying the herbicide directly onto the growing weed stems and leaves is called stem and leaf treatment. The method of stem and leaf treatment generally adopts a spray method, because the spray method makes the agent easy to adhere and penetrate into the weed tissue, and can obtain better medicine effect. According to the period of administration, it is divided into the treatment of stems and leaves before sowing and the treatment of stems and leaves during the growth period.
(1) Before the sowing, the stems and leaves are treated. Before the plants are planted or the flowers are transplanted, the weeds that have grown are sprayed with the chemicals. Herbicide is generally required to have a broad spectrum, and the agent is easily absorbed by the foliage, and falling on the soil does not affect the planting. Commonly used agents are paraquat and glyphosate. However, this method of application can only eliminate the weeds that have grown, and it is difficult to control the weeds.
(2) Stem and leaf treatment during the growth period The method of applying the herbicide to treat the stems and leaves of the weeds after the emergence of the lawn is called the stem and leaf treatment during the growth period. Herbicides are therefore required to have a high selectivity between the lawn and weeds.
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