Comparative study of carrier based materials for Rhizobium culture formulation

In the present investigation four carriers -bagasillo, peat, charcoal and coal were evaluated for the production of bioinoculants. The bacteria used for bioinoculant development were Rhizobium trifolii (MTCC-905) and Rhizobium meliloti (MTCC-100). Both bacterial strains were inoculated in all the four carriers separately. The bacterial population was determined in each carrier up to six month storage. Bagasillo maintain maximum population count 9.39 and 9.40 log cfu/gm for Rhizobium trifolii (MTCC-905) and Rhizobium meliloti (MTCC-100) respectively while coal supported minimum population count 7.28 for Rhizobium meliloti and 7.58 for Rhizobium trifolii. Finally the impact of six month stored inoculants on plant productivity was determined. Bagasillo with Rhizobium meliloti enhanced the seedling biomass by 47% while with Rhizobium trifoliiby 55%. Peat and charcoal with Rhizobium meliloti enhanced the seedling biomass by 34% and 28% respectively and with Rhizobium trifolii by 45% and 30% respectively. Coal with Rhizobium melilotishowed 08% increase of seedling biomass and with Rhizobium trifolii seedling biomass was enhanced by 10%. The bagasillo-based inoculant was much better than any other carrier-based inoculant taken in the study in enhancing the seedling biomass and the nodule number. The present study suggested the use of bagasillo as an efficient and cheaper carrier material.