Improved mycorrhizal colonization, nodulation status, biomass production and nutrient uptake in soybean due to inoculation with Bradyrhizobium japonicum

A pot culture experiment consisting of two cultivars (Viz., Kalitur and Lee), four different strains of Bradyrhizobium japonicum (SB 103, SB 113, SB 117 and SB 119) and uninoculated control was conducted using unsterilized sandy-loam soil under green house conditions. In both the cultivars VAM colonization by indigenous propagules improved significantly (P¼0.05) due to inoculation with various bradyrhizobial strains. Significant enhancement in synthesis of number of nodules, nodule dry biomass and nitrogenase activity was recorded due to bradyrhizobial inoculation. Amount of Nz-fixed in CVs. Kalitur and Lee due to inoculation with B. japonicum strains varied between 150.16 to 329.14 and 79.60 to 200.13 mg plant1, respectively. Improved VAM colonization due to introduced bradyrhizobia enhanced the P-uptake substantially in both the cultivars and thus complementing the process of Nz-fixation and dry biomass production.