Effect of bradyrhizobium inoculum and levels of phosphorus on the yield and quality of soybean

Background: Soybean is one of the major oil seed crops in Bangladesh. Combine application of Rhizobium inoculation and phosphorus fertilizer could be an important factor to get maximum yield and quality of soybean. Objective: To evaluate the effect of Bradyrhizobium inoculum and levels of phosphorus on yield and quality of soybean varieties. Methodology: The experiment evaluated three factors namely, varieties, Bradyrhizobium inoculum and phosphorus levels. The three varieties were: i) Binasoybean-1 ii) Binasoybean-2 and iii) BARI Soybean-6. Bradyrhizobium inoculum levels were: i) control (no inoculum), ii) 50% of recommended dose (RD) (25 g kg-1 seed) iii) 100% of RD (50 g kg-1 seed). The phosphorus levels were: i) control (no phosphorus) ii) 50% of RD (18 kg ha-1), iii) 100% of RD (36 kg ha-1). The experiment was laid out in a randomized complete block design with three replications. Data were recorded on yield, yield contributing characters and quality parameters of seeds. Results: Binasoybean-1 performed superiorly in terms of all the yield and yield contributing characters. Application of 100% of RD of Bradyrhizobium inoculum and application of 100% of RD of phosphorus also showed superior performance. Considering the interaction effect, the findings of the study indicate that Binasoybean-1 responded well to the application of 100% of RD of phosphorus and 100% of RD of Bradyrhizobium and gave maximum seed yield. The highest protein content (39.21%) was found in Binasoybean-2, 50% of RD of phosphorus with no Bradyrhizobium inoculum and the highest oil content was found (19.33%) in Binasoybean-2, no phosphorus and 50% of RD of Bradyrhizobium inoculum. Implication: Binasoybean-1 with the application of 100% of RD of phosphorus and 100% of RD of Bradyrhizobium might be recommended to obtain higher yield soybean in Bangladesh. Conclusion: From this study it may be concluded that recommended dose of phosphorus and Bradyrhizobium is beneficial for a higher yield of Binasoybean-1.