In the production of greenhouse vegetables Levin greenhouse construction process, often as a result of fertilization, antifreeze chosen heating and inferior films and other reasons that produce some harmful greenhouse gases, such as ammonia, nitrogen dioxide, and not be discharged in time to go when heated sulfur dioxide and carbon monoxide, as well as some of the harmful gases released from low-quality films, resulting in damage to vegetable production. Effective preventive measures can greatly reduce the harm of harmful greenhouse gases produced vegetables. A timely discovery of harmful gases harm ventilation, ventilation should be immediately discharged harmful gases, in order to reduce the extent of the plants suffer. Ventilation principle amount is leaked from small and large and airy open-top windows, not to use the bottom window ventilation. Avoid cloudy no ventilation, even in rain and snow, but also a little pass noon while the wind. Second, rational fertilization fertilization not excessive, especially to avoid partial nitrogen, and for cake fertilizer, animal manure and other organic fertilizer, must be administered after going to full maturity. Topdressing urea and other fertilizers to moderate, with the water or deep Shi Shi timely casing. Third, pay attention to the studio to produce regular checks of big films with or without ammonia or nitrite gases, can take films ritual precision pH test paper strips soaked in water droplets will then colorimetric card with colorimetric read the pH reached 8.2 Ammonia can be considered when harm occurs, to 6:00 can be considered harmful nitrous gas will occur. If harmful gases, the first to be replaced regular manufacturers of films, followed by liming may be appropriate and nitrification inhibitors, and a large number of irrigation eliminate the hazards of ammonia or nitrite gas produced. Fourth, pay attention to the fire heated antifreeze sealed when, to use less sulfur coal quality to fully burn, not pay attention to the stove and flue leak smoke, the best use of electric heating wire heating wire for heating and air frost warm. 4.24 For more information, please log on vegetable greenhouse construction www.wfdapeng.com