Abstract :
Combined inoculation of potted common bean plants with Rhizobium and Azospirillum significantly increased both upper and total nodule number and N2-fixation as compared with inoculation with Rhizobium alone. At an Azospirillum concentration of 108 cfu ml−1, the combined inoculation reduced root and shoot dry weight accumulation in comparison with Rhizobium alone and with uninoculated controls. However, when the combined inoculation was performed using a lower Azospirillum concentration (5 × 106 cfu ml−1), positive effects on plant growth were observed, although the enhancement of nodulation and N2-fixation were not as great as observed at the higher Azospirillum concentration. Field application of these findings are discussed.
