Abstract
The effects of different types of additional fertilizations (a compound fertilizer and Chiyoda-kasei) on the root-associated microbes of napa cabbage grown in an Andosol field were investigated by molecular community ana-lyses. Most of the closest known species of the bacterial sequences whose relative abundance significantly differed among fertilizers were sensitive to nitrogen fertilization and/or related to the geochemical cycles of nitrogen. The fungal community on the roots of napa cabbage was dominated by two genera, Bipolaris and Olpidium. The relative abundance of these two genera was affected by the types of fertilizers to some extent and showed a strong negative correlation.