Techniques for growing vegetables in greenhouses?

eight key points of vegetable cultivation techniques in greenhouse (greenhouse) 1. Balanced fertilization with formula The total salt content in the soil required for the normal growth of greenhouse vegetables is 2~3 mg/kg. If the root system exceeds 65 mg/kg, it will die due to reverse osmosis, and the yield will naturally decrease. The temperature and humidity in the greenhouse are high, the organic fertilizer decomposes quickly, and the phosphorus availability is 2~3 times higher than that in the open air. Nitrogen volatilization is large, and excessive fertilization can easily cause fertilizer damage. In the greenhouse, more phosphorus and potassium fertilizers should be applied, less nitrogen fertilizers should be applied, and cake fertilizers, human excrement and urine, and green manure stalks that have not been cooked should not be applied. Top dressing should be "eat less and eat more meals" to prevent excessive concentration. Generally, the cow dung of greenhouse chickens planted for more than three years is controlled within 25 kg each, and the chemical fertilizer is reduced by about 5%. For plots with high total salt concentration, pay attention to the application of organic cattle fertilizer, humic acid fertilizer and EM bacterial fertilizer, improve the ratio of soil carbon to nitrogen, loosen the soil for ventilation, dissolve salt and reduce fertilizer damage. At the same time, boron, zinc and magnesium are supplemented to balance soil nutrition. Second, the number of seedlings left in greenhouse vegetables with dense planting and sparse seedlings directly affects the yield. According to the determination, the nutrient consumption of 2 tomato plants in 1 square meter is 5%, and the fruit can get 5%; If four plants are planted per square meter, the vegetative body consumes 7%~8% of photosynthetic products, and the products can only account for 2%~3%. On the contrary, close planting will lead to low yield, and plants will grow up in vain because of competition for sunlight, and poor ventilation will easily infect various true and bacterial diseases. At the same time, in winter, the temperature is low, the light is weak, the photosynthesis is poor, and the synthesis of carbohydrates is less, so it must be planted sparsely. Generally, close planting in the early stage, thinning plants in the middle stage and thinning branches in the later stage, based on the principle that leaves and branches are not crowded, make full use of space and improve the total output and benefit of greenhouse. Third, the prevention and management of vines in greenhouse vegetables generally have weak plants and deep roots at seedling stage. Water control and plants should be controlled to promote roots, so that the underground part absorbs about 6% of photosynthetic products, and the underground and aboveground absorption accounts for 5% in the middle and late stage. In the early stage, the plant consumed 6% of nutrients and the reproductive growth accounted for 4%. 5% in the medium term; Late reproductive growth accounts for 6%~7%, and vegetative growth only accounts for 3%~4%. That is, to ensure a certain assimilated leaf area in the early stage, to control vines to promote fruit and improve yield in the later stage. Excessive vines will inevitably affect the nutrient accumulation of products, and the consumption of photosynthetic products is large and the yield is low. Therefore, overgrowth of vines is not a good vegetable. Fourth, scientifically fight drugs to treat diseases At present, the main way for vegetable farmers to solve vegetable diseases and insect pests in greenhouse is to fight drugs, but how to fight drugs well is also very particular. First, we must identify the disease and choose the right medicine. Generally, agents containing copper and zinc should be selected, which can not only sterilize, but also enhance the ability of plants to resist the invasion of germs and promote crop growth. Second, improving the ecological environment, reducing the humidity in the shed, such as drip irrigation under the film, reducing the number of plants and enhancing ventilation and light transmission can reduce pests and diseases and reduce the number of pesticides. Third, the death of seedlings caused by soil-borne bacteria should be prevented by medication at seedling stage. If it is not solved well in the early stage, the disease will be infected in the seedling stage and attack in the later stage, and the pathogen and bacteria have invaded the plant, and the effect of diligent pesticide application is not good. 5. Reasonable use of "greenhouse gas" In the process of greenhouse vegetable cultivation, especially in winter and spring, it is easy to produce harmful gases due to long-term sealing conditions, which is harmful to greenhouse vegetables. For example, nitrate nitrogen fertilizer and immature organic fertilizer are applied to the soil in greenhouse, which will produce a large amount of nitrous acid gas in the process of decomposition and decay. When it reaches a certain concentration in greenhouse, it will hurt solanaceae vegetables, making the ground leaves scalded like boiling water, and in severe cases, mesophyll will turn white and die. At the same time, greenhouse vegetables are particularly short of carbon dioxide when they are exposed to sunlight in the morning. Therefore, in winter and spring, for all kinds of vegetables that have been digested overnight, a proper amount of carbon dioxide gas fertilizer is added between the sun exposure in the next morning, which can make vegetables grow fast, prolong the growth period and increase production. When the temperature is high at noon, open the vent regularly to ventilate and reduce gas damage. 6. Drip Irrigation under Plastic Film Sunlight Greenhouse belongs to a closed and semi-closed environment, with slow evaporation and diffusion of water. Generally, the transpiration of plants and the evaporation of soil water are only equivalent to 5% of that in the open field, especially at night, on cloudy days and when the temperature is low, the relative humidity of the air is often saturated. Excessive humidity in greenhouse is the main cause of vegetable diseases. If the greenhouse vegetables are irrigated by drip irrigation under plastic film instead of flood irrigation, the greenhouse environment can be greatly improved, the humidity can be reduced, the greenhouse temperature can be increased, and the vegetable diseases can be reduced, so as to achieve the purpose of increasing production and quality. Greenhouse vegetables are covered with plastic film. According to the measurement, the indoor humidity at night can reach 95%~1% before plastic film mulching, and it will drop to 75%~8% after plastic film mulching. The incidence of drip irrigation under plastic film is 1%~15% lower than flood irrigation, saving water by 6% and increasing yield by 4%. Therefore, drip irrigation under plastic film is the most ideal irrigation method for greenhouse vegetables. Seven, arrange appropriate stubble times Many vegetable farmers believe that greenhouse construction costs a lot of money, and the land cannot be left idle all year round, so the main stubble is covered with secondary stubble, and the secondary stubble is the same as the main stubble. As a result, it is not as good as 251. In fact, it is better to plant one crop a year after a long winter, and two crops a year in spring and autumn. The old plants of eggplant, pepper, tomato and cucumber can be regenerated for one crop, and when the price is low, the seedlings should be set aside to dry the ground. In summer, leave a period of time to dig deep into the rain to press salt, expose to the sun for sterilization, close the shed to kill insects, and cure the soil, so that the main crop will have fewer problems and earn thousands of dollars or even more than 1 thousand yuan. Eight, master the greenhouse temperature Many vegetable farmers believe that the higher the greenhouse temperature, the faster the vegetables will grow. In fact, this is not the case. There is an upper limit requirement for the highest temperature for vegetable growth, that is, the highest temperature is 25℃~3℃. For different vegetables, the highest temperature is also different. The optimum temperature of warm cucumber and eggplant is 25℃~32℃, and the suitable temperature of cold-resistant vegetables such as celery and leek is 15℃~22.