The f ield trial results show ed that Radiant -S could effectively cont rol the grasses and broadleafw eeds in spring soybean f ield .The optium applicat ion timing w as at 2nd trifoliate -leaf stage of soybean , 3 -5leaves of g rass w eeds and 3 -7 cm hig h of broadleaf w eeds .The suitable dosage w as Radiant -S 1650 -1800ml/hm2 .These dosages were safe to spring soy bean .