Measures to prevent cold waves
When the cold wave comes, 5-7 in the morning is the time when the temperature is the lowest, and it is also the key time for cold resistance. At this time, only relying on greenhouse insulation may cause freezing damage to vegetables in the greenhouse. It is necessary to use external force to increase the temperature in the greenhouse to avoid freezing temperature. appearance.
(1) Heating facilities in the shed
The simplest and most direct method is to use an open flame to heat up, and place anti-frost candles or charcoal braziers around the shed, but attention should be paid to the safety of the use of open flames to prevent accidents such as carbon monoxide poisoning. Use high-power light bulbs to supplement light and increase temperature, turn on the lights for 3-4 hours in the morning and evening on cloudy days. Vegetables grow and strengthen their resistance, but keep the darkness of night 8 to allow the plants to respond to the dark. A small atmospheric pressure hot water boiler can also be used to input hot water and hot air into the shed through pipes to increase the temperature in the shed. Where conditions permit, heating equipment such as fan heaters can also be used, and the heating effect is obvious, but the cost is high.
(2) Supplementary carbon dioxide
When the temperature is low, the shed is closed, and carbon dioxide is supplemented artificially to enhance the coldness and increase the yield. Burning coal, oil and other combustibles in the shed can produce carbon dioxide, but the more commonly used method is to use dilute sulfuric acid and ammonium bicarbonate to chemically react to generate carbon dioxide gas in a simple gas fertilizer generator, and release it through pipelines in In the greenhouse; organic fertilizer, manure and rice straw can also be added to slowly release carbon dioxide as a supplement under the action of microorganisms.
(3) fumigant to drive away the cold
On a cloudy and rainy night, due to the clouds in the sky, the heat in the field is not easily radiated, so the temperature difference between day and night will not be too large. Using this principle, burning fumigants such as chlorothalonil, sulfamethoxazole and ketendazine in the greenhouse can form a thin layer of smoke on the top of the greenhouse to prevent the heat around the greenhouse from radiating to the high altitude, thereby reducing the amount of heat. Dispersion, to achieve the effect of heat preservation, while the fumigant can also prevent pests and diseases to achieve a multiplier effect. It is worth noting that the amount of smoke produced by fumigation should not be too strong, so as not to cause smoke and phytotoxicity to crops. In addition, the fumigant emits smoke quickly after ignition, and the applicator should leave the shed immediately to prevent poisoning.