目前,正是作物生长旺盛时期,急需为之补充肥料。在多种追肥方法中,有一种叫做根外追肥。根外追肥与根部施肥不同,它是通过作物叶部直接向作物供给养分。这种施肥方法的优点,一是可以防止养分在土壤中被固定或转化。例如,磷肥中的磷酸根易被土壤固定,赤霉素、B_9等生理活性物质在土壤中易转化失效,根外追肥则没有这些弊病。二是叶部对养分的吸收运转比根部快,所以根外追肥供给养分迅速,适于防治作物缺素症。在作物 At present, it is the period of vigorous growth of crops that urgently needs to be supplemented with fertilizers. In a variety of top-dressing methods, there is a called top-dressing. Top dressing and root fertilization different, it is through the crop leaves directly to the crop supply of nutrients. The advantages of this method of fertilization, one is to prevent nutrients in the soil is fixed or transformed. For example, phosphates in phosphate fertilizers tend to be fixed in the soil, gibberellin, B_9 and other physiologically active substances in the soil easily transformed failure, root top dressing is not these drawbacks. Second, the Ministry of leaf absorption and operation of nutrients faster than the roots, so top-grade fertilizer supply nutrients quickly, suitable for the prevention and treatment of crop-deficiency disease. In the crop