大豆雖然能靠根瘤固定大氣中遊離的氮，但是這隻占其需要量的３０％～５０％，qiyudehaixuturanggongying。suoyigeidadouzhuishidanfeinenggouzhuangganzengzhi
，kuodayemianmianji
，zengqiangguanghezuoyong，tigaokangninengli。dilijiaochadedikuai
，youmiaoqijiuyinggaizhuishi。dadoujinrukaihuaqihou，jiujinruleshengzhishengchangshiqi，zhegeshiqishidadouzhenggeshengchangfayuguochengzhongxufeizuiduodeshiqi。yinci，dadouchuzaimiaoqizhuishidanfeiwai，shihuaqihaiyingzhuifeiyici（氮、磷配肥合施用更好）。在盛花期進行葉麵噴肥也能獲取較好的效果。