Abstract

EM (effective microorganisms) is a commercial biofertilizer mainly consists of photosynthetic and lactic acid bacteria, yeast and actinomycetes. The present study was undertaken to investigate the effect of EM application and two strains of nitrogen fixing Bradyrhizobium japonicum (TAL- 102 and MN-S) on plant growth, nodulation and yield of black gram [Vigna mungo (L.) Hepper] in different soil amendment systems including unamended soil, farmyard manure (FYM) @ 5 g 100 g^-1, Trifolium alexandrinum green manure (GM) @ 4 g 100 g^-1 and recommended dose of NPK fertilizers. Nodule number was significantly enhanced by inoculation of either of the two B. japonicum strains in NPK and un-amended soils. A marked increase in nodule biomass was also recorded due to B. japonicum inoculation in these 2 types of soils. Grain yield was significantly increased by 46% due to either of the two B. japonicum strains in NPK amended soil. EM application markedly enhanced nodule number in FYM amended soil. Conversely, EM application in combination with either of the two B. japonicum strains resulted in pronounced reduction both in number and biomass of nodules in NPK fertilizers amendment. EM application significantly enhanced grain yield by 48% in NPK amendment without B. japonicum inoculation.

Key words: Black grams, Bradyrhizobium japonicum, effective microorganisms, nitrogen fixation, soil amendments.