Matters needing attention in greenhouse vegetable management in low temperature, rain and snow weather

Management of rain and snow weather shed

At present, the cold spell is approaching, the emergence of low-temperature rain and snow weather, in order to prevent low-temperature freezing damage of strawberries and vegetables in the greenhouse, all villages should earnestly strengthen low-temperature anti-freezing. The specific comments are as follows:

First, we should pay attention to the cover of grass grass. According to the temperature of the day, the temperature of the greenhouse should be about 18 ℃ one hour after the cover, which is higher than 18 ℃ late cover and lower than 18 ℃ morning cover. On the night of overcast and snowy weather, a layer of cold-proof plastic film is covered on the grass curtain, which can increase the indoor temperature by 2 ℃ to 3 ℃. If raising seedlings in the shed, we should also build a small arch shed on the seedling bed, so that the effect of heat preservation and moisture conservation will be better.

Second, we should pay attention to supplementary lighting. Greenhouse vegetable production is not afraid of cold weather, but not enough light in even overcast and snowy days. Therefore, it is very important to enhance and supplement the light in the greenhouse to ensure the normal growth of vegetable plants. The method is that a reflective film can be hung on the back wall of the shed to increase the light intensity of the cultivation bed, and an electric lamp can also be installed in the shed. Under the condition of weak light in the overcast, snow and sky, the lights can be turned on for about 3 hours in the morning and evening, which can not only supplement the light, but also increase the temperature in the greenhouse and promote plant photosynthesis.

Third, we should pay attention to adjusting the air in the shed. In the cold season, the greenhouse is almost in a closed state because of low temperature and less ventilation, so it is easy to cause excess oxygen and insufficient carbon dioxide in the air, which has a great impact on the respiration of vegetable plants. Carbon dioxide fertilization technology, such as the reaction of sulfuric acid with ammonium bicarbonate, can be used to adjust the air composition in the greenhouse, supplement the content of carbon dioxide, and enhance the cold resistance of vegetable plants.

Fourth, we should pay attention to foliar spraying fertilizer liquid. Under the condition of low temperature and weak light, the ability of root system of greenhouse vegetables to absorb nutrients was greatly weakened, and the ability of photosynthesis to produce nutrients was even worse. At this time, we should use little or no growth hormones as far as possible, and the effect of foliar spraying fertilizer solution is more obvious.

Fifth, we should pay attention to irrigation to preserve soil moisture and protect roots. In the critical period of vegetable plant growth, choosing sunny weather (the temperature in the greenhouse is above 20 ℃), dark irrigation or drip irrigation under plastic film can effectively prevent frost damage. This is because the specific heat of water is higher than that of air, the heat dissipation is slow, the soil water content in the greenhouse is moderate, the heat preservation performance is good, and the roots of vegetable plants can be protected from freezing damage.

Sixth, attention should be paid to strengthening post-snow management. In the overcast and snowy weather, the temperature in the shed is relatively low and the plants are dormant; but once the weather clears up, the temperature in the shed rises rapidly, which is easy to cause the leaves to lose water and wilt. In order to prevent the plant from wilting, the cover grass should be lifted repeatedly and water can be sprayed on the leaf surface if necessary, so that the temperature can rise slowly, so that the vegetable plant can have a process of adaptation to the environment, and it will take 2 to 3 days to resume normal growth. Otherwise, it will cause "ten days to be suppressed, one day to grow abruptly" and the seedlings will flash, so that when the temperature drops again, it is more likely to produce frost injury.