1. Select a suitable insect net according to the charac […]
1. Select a suitable insect net according to the characteristics of vegetables
For the production of vegetables, a white or silver-gray net of 20 to 32 mesh is preferred. For shade-tolerant vegetables, black insect-repellent nets should be used to enhance the shading effect; Xiguang vegetables should use white insect-repellent nets with few meshes and large meshes; the virus-damaged vegetables use silver-gray nets to prevent disease and disease. Under the premise of effectively preventing the main pest of the smallest shape on vegetables - aphids, the mesh should be as small as possible to facilitate ventilation.
2. Soil disinfection and chemical weeding before covering to kill eggs and germs remaining in the soil and control weed growth.
(1) Before the cover, the soil is ploughed, sun-dried, and disinfected. The methods of spraying, watering, and poisonous soil are used to kill the soil pathogen and cut off the transmission route. It can be sprayed with 3 to 4 kilograms per 667 square meters or trichlorfon and phoxim for soil treatment. It can also be treated with 2 to 5 kilograms per 667 square meters of Miller granules to kill underground pests. Tiger, donkey, etc.
(2) In order to protect the tightness of the insect-proof net, it is not advisable to enter the net for manual weeding and seedlings. Therefore, before applying the insect-repellent net, the herbicide is applied to the weeds with more weeds to prevent weeding, providing a favorable growth environment for crop production. After sowing, spray 72% of the herbicide 80-100 ml per 667 square meters.
(3) Fine soil preparation, applying sufficient base fertilizer, generally no longer topdressing in the growing season. When the organic fee is applied, the skilled manure is applied to avoid the application of the manure with the eggs and the bacteria to the vegetable field.
3. Implementation of full growth period coverage
There is not much shading in the insect-proof nets. It is not necessary to expose the night cover or cover the weather. It should be closed cover during the whole growth period, until the harvest is not revealed. When covering the greenhouse, the insect-proof net can be directly covered on the scaffolding, and the surrounding area is compacted with soil or brick to prevent the pests from swimming into the spawning. The net must be pressed with a pressure cable to prevent the wind from blowing the net. When the small arch shed is covered, the height of the shed should be higher than the height of the vegetable crop. Generally, the arch height is more than 90 cm, so that the leaves are not close to the insect net, and the pests outside the net are taken to eat the leaves and lay eggs.
4. Do a good job of comprehensive supporting measures. Under the premise of covering the insect-proof net, adopt comprehensive measures such as selecting heat-resistant and disease-resistant varieties, applying sufficient maturity, pollution-free organic fertilizer, rational use of biological pesticides, and selecting non-polluting water sources. It adopts methods such as changing crops and pre-sowing soil insecticide treatment.
5. Attention to the problem
(1) Insect net is made of polyethylene as raw material, which is drawn by drawing and has a certain shading and cooling effect. However, during the process of use, the pressure is tight, the air circulation is not smooth, and the temperature and humidity are relatively increased. The study found that the higher the outside temperature, the greater the increase in temperature and humidity in the net, and the greater the effect of warming and humidifying the shed. High temperature and high humidity are bound to be unfavorable to the growth of vegetables. It is easy to cause rotten seeds, rotten seedlings, long lengths, lighter leaves, slender plants, and severe seedlings and dead. Therefore, it is advisable to use a greenhouse cover in production and pay attention to controlling the humidity in the shed. According to the experience of Suzhou, from July to August, it can only be covered by greenhouses. In September, it can be covered with greenhouses, covered with small sheds, and covered with flat covers.
(2) Because the insect net has strong moisture retention, the field management is more dry than the open field. Watering the cabbage is changed from water in the morning and evening to water in the morning, and it is generally not watered at night.
(3) After covering the insect net, the vitamin C and the clean vegetable rate are higher than the open field, and the appearance color is better than the open field. It is popular in the market, but the chlorophyll content in the leaves is reduced, and the nitrate content is increased compared.