塑料大棚栽培蔬菜,常因施肥方法不当,同时忽视通风换气,使棚内有毒气体过量造成气害,而气害又常被误诊为病害,导致歉收甚至绝收。一、气害种类1.氮气。由于施用过量尿素、硫酸铵等速效化肥,或施肥方法不当,如施用未经腐熟的有机肥,在棚内高温条件下分解产生氨气,就会危害蔬菜,使叶缘组织出现水渍状斑点,严重时整叶萎蔫枯死,常被误诊为霜霉病或其他病症。对氨气敏感的蔬菜有黄 Plastic greenhouse cultivation of vegetables, often due to inappropriate methods of fertilization at the same time ignore the ventilation, the greenhouse gas poisoning caused by excessive, and gas hazards are often misdiagnosed as disease, leading to poor harvest or even income. First, the type of gas 1. Nitrogen. Due to the application of excessive urea, ammonium sulfate and other quick-acting fertilizers, or improper fertilization methods, such as the application of uncompounded organic fertilizer, decomposed in the greenhouse under high temperature ammonia produced, it will endanger the vegetables, leaves marginal tissue water spots In severe cases, the whole leaf withered wilt died, often misdiagnosed as downy mildew or other illnesses. Ammonia-sensitive vegetables have yellow