Bradyrhizobium occurrence in nodules of perennial horsegram.

The introduction of a forage legume into a tropical pasture should decrease the need for N fertilizer, provided biological N fixation (BNF) contributes enough to compensate for exported N. Macrotyloma axillare (perennial horsegram) is a suitable legume for composing mixed pastures, and our hypothesis is that the isolation of indigenous rhizobia from roots and rhizosphere is the way of achieving an efficient inoculant to maximize BNF to the legume. Nodules and rhizosphere soil taken from M.