Improvement of Rhizobial Inoculants: A Key Process in Sustainable Soybean Production

Symbiotic nitrogen fixation has important role in sustainable soybean production because of utilization of atmospheric nitrogen for soybean nutrition. Pre-sowing soybean seed inoculation with selected rhizobial strains is used to improve the amount of symbiotically fixed nitrogen. Besides strain selection, suitable inoculant formulation is important for the success of inoculant application. The aim of this research is the evaluation of symbiotic efficiency and compatibility of Bradyrhizobium japonicum strains with soybean cultivar as well as possibility of using different inoculant formulation in soybean production. During two years of field trials in eastern Slavonia, nodule dry weight, nitrogen content in plant, seed yield, 1000 seeds weight, protein and oil content in seed were determined. Results of this study indicate that inoculant formulation as well as the use of selected strains affects nodulation, symbiotic and agronomic properties of soybean. Despite the differences in results in both experimental years, it can be concluded that the strains used as well as inoculant formulations are suitable for soybean inoculation in agroecological conditions of eastern Slavonia