利用塑料大棚栽培蔬菜,往往由于施肥方法不当等原因,忽视了棚内通风,使棚内氨气、亚硝酸气、氯气、乙烯、一氧化碳等有毒有害气体过量蓄积,为害蔬菜。为了防止棚室内有毒气体为害发生,在管理上应注意以下几点: 1.不用未经充分腐熟的粪肥或新鲜厩肥作基肥。未经腐熟的有机肥在发酵过程中产生的亚硝酸气体、二氧化硫、硫化氢等有毒气体会为害蔬菜。 2.不施用碳酸氢肥作追肥。因为施用碳酸氢铵后棚内会产生高浓度的氨气,致使蔬菜氨中毒。追肥中以施尿素、硫铵为好,施后应立即浇水,或穴施覆土。 3.低温季节追肥后,应适当增加放风量,排除有毒气体。 4.对大棚加温。不用含硫量高的劣质煤,而且要等到煤正常燃烧后再将煤炉搬人 The use of plastic greenhouse cultivation of vegetables, often due to improper fertilization methods and other reasons, neglected shed ventilation, so shed ammonia, nitrous acid, chlorine, ethylene, carbon monoxide and other toxic and harmful gases over-accumulation of harmful vegetables. In order to prevent harmful indoor greenhouse gas hazards occurred in the management should pay attention to the following points: 1. Do not use inadequate maturity of manure or fresh manure as a base fertilizer. Nitrogenous gas, sulfur dioxide, hydrogen sulfide and other toxic gases produced by the decomposed organic fertilizer during fermentation will be harmful to vegetables. 2. Do not apply bicarbonate fertilizer for top dressing. Because the use of ammonium bicarbonate shed will produce high concentrations of ammonia, resulting in vegetable ammonia poisoning. Top dressing to urea, ammonium sulfate is good, immediately after the application of watering, or hole soil. 3. After the season dressing, should be appropriate to increase the amount of ventilation, excluding toxic gases. 4. Warm the greenhouse. Do not use low sulfur content of high-quality coal, but also to wait until the normal combustion of coal and then move the coal stove