The use of greenhouses for winter off-season vegetable production is a great innovation in the history of vegetable development in the world. However, due to the heavy snow weather in winter, it is often under the condition of low temperature and low illumination, which brings certain difficulties to the production of vegetables. Without scientific management, it will cause undue economic losses to vegetable farmers. Regardless of the technical requirements for greenhouse vegetable production in winter, as long as good “three levels†and “two points†are taken care of, the greenhouse vegetable production in winter can be carried out smoothly, and the purpose of increasing production and income can be achieved, satisfying the desire of people to eat summer vegetables in winter.
One and three levels
1, temperature off
Solar greenhouse vegetable production in winter is primarily temperature management. The problem often arises in production is low temperature barriers. If the greenhouse temperature is lower than 20°C, normal flowering, pollination, fruit formation, or fruit formation may not occur; if the temperature of the greenhouse is lower than 16°C before 15 o'clock in the afternoon until 22 o'clock in the morning, then the temperature in the leaves Nutrients cannot be transferred and accumulate on the leaves, leading to blisters, thickened leaves, dark greens, dwarf plants, melons, flower toppings, etc.; if the temperature is lower than 10°C in the middle of the night, it will cause cold damage, and leaves yellow Change, dryness, death. For this reason, the effective measure in production practice is to use the temperature four-stage management method.
2, humidity off
The high humidity in the greenhouse in winter is very unfavorable for the normal growth and development of vegetables, and it encounters low temperature and high humidity. It easily induces diseases such as downy mildew, angular spot disease, gray mold, sclerotinia, and late blight. phenomenon. The main measure is ventilation and humidity.
3, light off
Without sunlight, plants cannot carry out photosynthesis. The main measures adopted in lighting management are: first, cover the cover as soon as possible; second, encounter rain and snow, but also insist on seeing light; third, if it is continuous cloudy; when it meets a sunny day, it must be covered. Fourth, the dust on the shed film is often removed; the fifth is to hang a light curtain on the back wall of the greenhouse.
Two or two points
1, CO2 fertilization
Winter greenhouse vegetable production is carried out in a relatively closed environment. The raw material CO2 needed for photosynthesis of vegetables is seriously insufficient. In general, the CO2 saturation point required for vegetable production is 1000-1500 ppm, while the CO2 concentration in the atmosphere is only 300 ppm, and the CO2 concentration in the greenhouse is only 150 ppm from 9:00 am to 10:00 am. Increased CO2 production can increase production by 20-30%.
2, application methods
If diseases occur in the greenhouse in winter, they need to be treated with pesticides. They should be selected in the morning on a sunny day and combined with air release and dehumidification. However, it is best to use dust or aerosols to reduce the humidity in the foliage and in the greenhouse.
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