In autumn and winter, there is one autumn rain and another cold, and the temperature often drops cliff-like. When encountering a cold current, the temperature drops rapidly and then recovers. If you want to extend the growth period of vegetables in the arch shed, the foundation of the sunshine board greenhouse is to improve the daily heat preservation of the shed. Generally, you can add a shed film, non-woven fabric, etc. on the arch shed.
1. Set up non-woven fabrics on both sides and north side of the arch shed.
The two sides of the arch shed have a large contact area with the outside world, and the heat loss is faster. Generally speaking, the initial chilling damage is on both sides of the arch. Therefore, vegetable farmers should cover both sides of the arch shed with non-woven fabrics, straw curtains, etc., which can greatly improve its thermal insulation. Especially for the east-west arch shed, a layer of straw wind barrier can be set on the north side to reduce air flow and heat loss.
In addition, vegetable farmers must pay special attention to repairing damaged parts to ensure that there are no omissions between the vents and the ground, and to reduce the air circulation inside and outside the arch shed at night.
2. Set up a shed
Shed film is the most commonly used heat preservation method for vegetable farmers. Adding a layer of film to cover can increase the temperature in the shed by 2-4°C. When the outside temperature drops below 8°C, a set of film should be added to the arch shed to increase the night temperature in the shed as much as possible to promote the growth of vegetables.
After adding a shed film, it is necessary to strengthen the temperature and humidity control, especially when the ventilation becomes poor, it is easy to produce dripping, and the humidity in the shed increases greatly. It is necessary to strengthen the prevention and control of humidity-loving bacteria and fungal diseases, such as bacterial keratoderma and soft rot Diseases, fungal gray mold, sclerotinia, downy mildew, etc. Vegetable farmers can use air disinfection tablets for air disinfection every 3-4 days to control the spread of airborne fungal diseases; spray chlorobromoisocyanuric acid, zinc thiazole, thiazolium and other agents at intervals of 5-7 days. When medicament, the stems and leaves and the ground should be sprayed to reduce the spread of surface pathogens.
Enhance the cold resistance of vegetables
The difference in cold resistance of vegetables is very important for extending the growth period of vegetables. The cold resistance of the same plant is not static, but constantly changes with weather, water and fertilizer and other conditions. Under adversity conditions such as continuous rainy days, the photosynthetic product of the plant is insufficient, and the cold resistance will be significantly reduced. Inorganic salts, soluble sugars, amino acids, nucleotides, etc., all have a vital impact on the cold resistance of plants. One of the most important purposes of cultivating strong trees that we usually emphasize is to strengthen the accumulation of organic products, ensure adequate nutrient supply for plants, and maintain the stability of plant resistance.
The adaptation of plants to adversity is also affected by the regulation of hormones. Growth inhibitors such as abscisic acid and ethylene can significantly improve the cold resistance of plants, while growth promoters such as gibberellin and 2,4-D can reduce the cold resistance of plants. In recent years, the effect of using functional substances such as chitin and alginic acid on vegetables has been verified. Chitin can induce physiological changes of vegetables themselves and produce substances that improve vegetable resistance. After spraying with alginic acid, it can induce the differentiation of flower buds, improve the stress resistance of vegetables, and the effect is obvious.
Before the arrival of the cold current, vegetable growers can spray plants with total nutrient foliar fertilizer, amino acids, sugar or glucose, together with alginic acid, chitin, ethylene, etc., which can effectively supplement plant nutrition and improve resistance under adversity conditions.
Strengthen management after the cold current
After the cold wave, the weather quickly turns fine, and the temperature in the shed generally rises relatively quickly. Management must be strengthened to reduce secondary damage to vegetables after the cold wave. One is to pay attention to the slow temperature rise. At this time, vegetable farmers should ventilate early to keep the temperature in the shed rising steadily. The highest temperature in the morning is best not to exceed 25°C to ensure that the vegetable affected tissues have time to recover. The second is to spray water to increase humidity. Ventilate early after a sunny day, and the humidity in the shed will drop quickly. When the plants are found to be wilting, you should immediately spray warm water on the plants to increase the humidity in the shed and reduce the intensity of leaf transpiration. The third is to supplement nutrients. When spraying water, you can also add chitin, photosynthetic dynamic total nutrient foliar fertilizer, white sugar, etc. to supplement foliar nutrition and promote rapid recovery of leaf function.