叶面施肥即根外追肥,是将肥料溶解在水中,再用喷雾器等将液肥喷施在作物叶片上的施肥方法。叶面肥施肥比根部施肥提供养分快,还能避免养分在土壤中的固定和退化,提高养分利用率。叶面施肥要做到“六要”。一要掌握好浓度。叶菜类蔬菜喷施叶面肥,浓度过高,会造成药害,灼伤叶片,危害人体;浓度过低,不仅会增加工作量,而且还达不到补充作物养分的要求。一般常用肥料最佳浓度为:尿素2%,磷酸二铵0.2%—1%,硫酸锌0.05%— Foliar fertilization is the root top dressing, is the fertilizer dissolved in water, and then spraying the liquid fertilizer and other fertilizers applied to crop foliage fertilization methods. Foliar fertilization than the root fertilization to provide nutrients faster, but also to avoid nutrient fixation in the soil and degradation, improve nutrient utilization. Foliar fertilizer to be done “six to ”. First, to master the concentration. Leafy vegetables spraying foliar fertilizer, the concentration is too high, will cause injury, burns leaves, endangering the human body; concentration is too low, not only will increase the workload, but also not enough to meet the requirements of crop nutrients. Commonly used fertilizer best concentration: urea 2%, diammonium phosphate 0.2% -1%, zinc sulfate 0.05% -