The good yield of greenhouse vegetables has attracted more and more farmers' friends to participate in planting. How to effectively manage greenhouse vegetables in winter and spring? On January 29, the reporter interviewed Teng Youde, a vegetable expert from the Provincial Academy of Agricultural Sciences. He introduced the main points of winter and spring management of greenhouse vegetables in detail.
Prevention of common diseases in greenhouses
"Greenhouse vegetables are cultivated in protected areas and are produced in a unique and small environment. Therefore, for some common diseases, farmers' friends must understand and prevent them," Teng Youde said.
In common diseases, ammonia harms the most. "Usually when urea or other nitrogenous fertilizers are used excessively in greenhouses, or if unfamiliar organic fertilizers are used, a large amount of ammonia can easily be produced, which will cause harm to vegetables." The symptoms of vegetable ammonia damage are stains on the edges of the leaves, and thus change. Brown dead.
How to prevent it? "First, strictly control the amount of use, many or no urea; Second, do not apply organic fertilizers that are not fully cooked; Third, strictly according to the amount of standard application, each time nitrogen fertilizer 0.4-0.6 kg / square meter, carbon ammonia less than 0.8 kg per square meter If the dosage is not enough, we can adopt a small number of times the principle." Teng Youde introduction.
Since greenhouses use relatively more chemical fertilizers, over time, the salt accumulation in the soil will exceed the scope of vegetable adaptation and cause salt damage. "If salt is present, it will show the shortness of the plant, the thicker leaves, and the symptoms of dry or browned leaves and flowering and falling of fruits when they are severe." Teng Youde proposes a method to prevent and treat salt, "do not apply or less cure. When chlorides are applied, they are combined with organic fertilizers; when chemical fertilizers are applied, they are applied in strips or holes; when the temperature is high, the amount and times of chemical fertilizers are appropriately reduced; watering or irrigation is used to reduce the soil salt concentration.
Teng Youde also reminded that the number of greenhouse vegetable crops is too many, and the occurrence of pests and diseases will be relatively heavy. After the vegetables are harvested, it can be improved by making use of crop rotation. In addition, the garden soil should be disinfected prior to sowing or planting vegetables in the second season, which can effectively prevent blight and root rot. The method is to use 40% of carbendazim, or 50% thiophanate, or 70% of pentachloronitrobenzene, 8 to 10 grams of vegetables per square meter, 3 kilograms of water, and about 6 kilograms of soil. Stir and mix evenly, sprinkle in the vegetables and disinfect it.
Pay attention to cold-proof seedlings at the seedling stage
Teng Youde introduced that in the period of vegetable seedlings, attention should be paid to temperature control. It is necessary to prevent cold seedlings from being caused by too low a temperature, and to prevent the temperature from being too high and causing seedlings to steepen. In the temperature control, the general night temperature is 5-7 degrees lower than the day, cloudy and rainy days, the temperature is lower than the sunny days, soil temperature is slightly higher than the temperature, these are the need to pay attention. When growing seedlings in a seedbed with culture soil, no top dressing may be applied or applied. After the emergence and seedling stage, the moisture content in the air should be higher. After sub-seedling survival or before planting, proper control of moisture. Attention should be paid to the hardening of the seedlings. Before and after the planting, the temperature should be gradually reduced and watering should be reduced. The seedlings should be adapted to the external environment after the planting.
Scientifically regulate greenhouse temperature
"According to the needs of crop growth, it is very important to carry out temperature control. There are three methods: insulation, warming and cooling." Teng Youde said that he introduced three methods of insulation, one is to cover the entire plastic film, that is, to cover the greenhouse. Plastic film, which is also called double-film insulation, can prevent evaporation of water, maintain the temperature of the greenhouse, and can increase the temperature of the ground by 2-3 degrees. Second, it sets up a small arch shed, that is, a small arch shed can be built in the greenhouse, also called double shed insulation. Keep the temperature within the small arch shed above 10 degrees; third, cover the straw curtain, that is, cover the straw curtain on the shed or in the shed, it can also play the role of insulation, but the disadvantage is that there is moisture, often making the indoor humidity high, affecting The growth of vegetables, it should pay attention to the occasional use.
To prevent chilling or injury caused by low temperatures in the shed, warming measures must also be taken. There are four ways: one is to raise the temperature in the shed, the other is to heat the lighting in the shed, and the third is to heat the electricity, that is, to use the electric heating line to heat it. The fourth is to provide a place where the conditions are, install the steam pipe, and use steam to raise the shed. temperature.
How to scientifically regulate temperature? “In the winter season, the emphasis is on warming; in early spring, attention should be paid to insulation. After the spring temperature rises, attention should be paid to cooling.†There are many ways to reduce the temperature. The first is to sprinkle water, that is, to sprinkle water in the shed to reduce the temperature inside the shed; Membrane, that is, part or all of the shed film is opened, and the temperature in the shed is lowered by ventilation; thirdly, the shed door is opened, that is, the shed door is opened, and the temperature in the shed is distributed to cool the shed.
Timely regulation of light and humidity
Now thanks to the higher income from vegetable cultivation, farmers' friends are also willing to invest. When building large sheds, high quality shed films are generally used.
How to adjust the light so that the vegetables grow better? Teng Youde introduced, "For membranes with water droplets, metronidazole metronidazole can be used. This is a powdery, high-concentration, easy-to-use, low-cost, film-free, bactericidal effect. Improve lighting conditions in the shed, but also prevent the water droplets from getting infected.Set up a silver reflective film, enhance the direct light intensity on the northern side of the greenhouse, and increase the temperature of the shed. According to the test, the illuminance can generally be increased by 9% to 40%, and the temperature of the shed can be increased by 1.5 - 3 degrees. Under the condition of permitting heat preservation, part or all of the shed film can be peeled off to increase the light. In the summer when the light is strong, the shade net can be covered to reduce the direct light intensity and prevent direct rainstorm."
The humidity in the greenhouse is too large and the vegetables are susceptible to disease. Therefore, it is very important to regulate the humidity. Membrane drip irrigation, underground infiltration and other facilities can be used to save water, save labor, reduce evaporation, reduce greenhouse humidity, destroy pathogen infection and survival conditions, and suppress and reduce the incidence of vegetable diseases.
Covering the mulch in the shed can greatly reduce surface water evaporation and effectively reduce the humidity in the early spring shed. Uncovering the film, opening the film, and appropriately strengthening ventilation can also effectively reduce the humidity in the booth.
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