根外追肥,是在作物生长发育期间将水溶性肥料的低浓度溶液喷施于作物叶面等地上部分的一种施肥方法。特别是农作物生长后期,仍然需要消耗大量的营养物质,但此时作物的根系已逐渐衰老,吸收养分的能力降低,如进行土壤施肥,不但营养吸收利用缓慢,而 Root top dressing, is a fertilization method of spraying low concentrations of water-soluble fertilizers on top of crops such as foliage during crop growth and development. In particular, the latter part of the crop still needs to consume a large amount of nutrients, but at this time the root system of the crop has gradually become senescent and the ability to absorb nutrients is reduced. For example, soil fertilization not only slows the absorption and utilization of nutrients,