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大棚栽培蔬菜,应注意抓好“三防”。“三防”是指防盐化、防高温、防肥害,只有抓好了“三防”,大棚蔬菜才能高产优质,取得较高的经济效益。1.防盐化导致大棚土壤盐化的原因,一是大棚内不受降雨的影响,其盐分不能随雨水流失和淋浴;二是大棚内灌水次数多,土壤团粒结构遭到破坏,大孔隙减少,盐水不能下渗;三是生施人粪尿,使一些硫化物硝酸盐等残存于土壤中;四是化肥施用量过大。
Greenhouse cultivation of vegetables, should pay attention to grasp the “three defenses.” “Three defenses” means salinization prevention, high temperature prevention and anti-fatal damage. Only by doing so can the high-yielding and high-quality greenhouses produce high economic benefits. 1. Salinization causes the saltification of greenhouse soil causes, first, the greenhouse is not affected by rainfall, the salt can not rainwater loss and shower; Second, the number of irrigation in the greenhouse, soil aggregate structure is destroyed, the reduction of macropores , Salt water can not penetrate; third is imposing human excrement, so that some sulfide nitrate remaining in the soil; Fourth, excessive fertilizer application.