Vegetables in greenhouse in winter beware of harmful gas hazards

Vegetables in greenhouse often suffer from air and wind damage in winter, which reminds vegetable farmers to pay attention to it.

I. the harm and prevention of gas damage

Air damage often fumigates vegetables in a short time, resulting in a significant reduction in vegetable production and a serious decline in quality.

1. Ammonia. A large number of organic fertilizers such as undermature chicken manure, human manure, cake fertilizer and urea were applied in the greenhouse, which could be fermented and decomposed in high temperature for 3 to 4 days to produce a large amount of ammonia. Ammonia invaded from the stomata of the leaves, and the damaged parts were mainly leaves. The injured part was flooded, the leaf color became light, white or lavender, and the leaf edge was burned. The damage occurred in the whole greenhouse, and the upper leaves of the plant were heavy, which could cause the plant to die. Cucumbers, tomatoes, chili peppers and celery are the most sensitive to ammonia and suffer the most.

two。 Nitrous acid gas. After a large amount of organic fertilizer and ammonium nitrate were applied in the greenhouse, a large amount of nitrite gas was emitted from the soil when the soil changed from alkaline to acidic. The damaged leaves had irregular chlorotic white spots or brown spots, and when the concentration reached 10 mg / kg, the veins also became white and withered. Vegetables such as tomato, eggplant, lettuce and pepper are sensitive to nitrous acid.

Preventive measures: first, it is necessary to apply reasonable fertilization. in the greenhouse, do not apply a large number of undermature organic fertilizers such as chicken manure, cake fertilizer, human manure and urine, as well as chemical fertilizers such as urea and diammonium phosphate. Compost made by enzyme bacteria or fully mature organic fertilizer can be used. Formula fertilization is adopted to reduce the use of chemical fertilizer. At the same time, pay attention to the selection of reasonable fertilization methods, urea, diammonium phosphate and other chemical fertilizers should be buried and watered to avoid the volatilization of harmful gases as far as possible. The second is ventilation. In the management of vegetables in the greenhouse, attention should be paid to regular ventilation to reduce the accumulation of harmful gases in the greenhouse. After topdressing, it is necessary to strengthen ventilation when the temperature is high at noon to speed up the emission of harmful gases.

Second, the harm and prevention of wind damage

Chuantang wind is a rapid convection of cold air caused by lax closure of shed doors or vents in winter, which has a great impact on the growth of vegetables. After a gust of cold wind, vegetables grow poorly in light and wilt leaves and drop flowers and fruits in heavy cases. Although it is less destructive than gas damage, it often gives vegetable farmers a headache. The most effective measure to prevent the wind in the hall is to set up a wind shield at the entrance and vent to cushion the direct blowing of the wind to vegetables. Especially in the doorway, in addition to setting a wind shield, the shed door had better hang a cotton door curtain, which can effectively prevent the entry of the wind through the hall. For the vegetables harmed by the wind, foliar fertilizer or plant growth regulator should be sprayed in time to promote their growth as soon as possible.

Chen Shuqiao, Plant Protection Station of Xinji City