Six key points of soil fumigation in greenhouse
Soil chemical fumigation is an effective method to control root knot nematodes and soil borne diseases. However, some vegetable farmers failed to effectively control the pests and diseases in the shed due to improper methods of soil fumigation. Therefore, the following points should be paid attention to when fumigating soil chemicals:
1. Fumigation time should be timely.
Soil fumigation should be carried out immediately after the harvest of the previous crop. At this time, most root knot nematodes gather on the soil surface, which is easier to kill. Otherwise, the effect of soil disinfection after diseases and pests migrate to the deep soil will be reduced, leading to some bacteria escape by luck, which will happen again in the next year.
2. The medicament should be properly selected.
The main soil fumigants on the market are methyl bromide, cotton wool, etc. These agents have a certain role in the prevention and removal of fungi, bacteria, nematodes, but many are highly toxic and highly toxic products, which are not safe for humans and animals. Therefore, it is recommended to choose efficient, low toxic and environmentally friendly soil fumigants and disinfectants.
3. The environmental conditions should be suitable.
Disinfection with soil fumigant, the mechanism of sterilization (insect) is mostly: after the chemical agent is applied to the soil, the original liquid or solid changes into gas, and the gas diffuses among the soil particles, killing the pathogenic and harmful organisms in the soil that can cause plant disease, so as to prevent disease. Therefore, it is required that: ① the permeability of the soil is good. Before soil fumigation, the plot to be treated shall be turned over 20-30cm. ② The soil moisture is suitable. In general, the soil fumigation effect is best when the soil moisture content is 50% - 70%. ③ The soil temperature is reasonable. The ideal temperature can make the pests in a "living" state, which is convenient for the fumigant to play a better role. Generally, the ideal soil temperature is 15 cm, 15-20 ℃.
4. Prevent reinfection after fumigation.
The fumigant only eliminated the existing pests and diseases in the soil, and there was no effective period, so it was powerless to deal with the reintroduced pests and diseases. The plot where nematodes and other pests and diseases are found soon after fumigation may not be fumigated well, but caused by the re infection of pests and diseases, such as seedlings with pests and diseases. Some are soil particles with diseases and insects washed by rainwater after fumigation, and diseases and insects outside the shed are brought in with shoes. Attention should be paid to these matters, and try to cut off the channel for nematodes to enter again.
5. Do not turn the soil too deep after smoking.
If the soil after fumigation is turned much deeper than that before fumigation, or even if it is not turned before fumigation, it will turn up nematodes and other diseases and pests that are not suffocated in the deep layer.
6. Supplement organic fertilizer after fumigation.
The soil disinfection fumigant will not only kill harmful organisms, but also kill beneficial organisms. Therefore, the sterilized soil should be fertilized with bio organic fertilizer to supplement the number of beneficial organisms.