Effects of biofertilizers, lime and inorganic NPSB fertilizers on nodulation, growth and yield of soybean (Glycine max L. Merrill) in Assosa Zone, Western Ethiopia

The productivity of soybean in Assosa Zone particularly in Assosa and Bambassi districts is very low due to poor soil fertility management practices which resulted in severe soil acidity and low N-fixing inoculant in the soil. Hence, this experiment was conducted during the main cropping season of 2019 and 2020 in Assosa and Bambassi districts to evaluate the effect of biofertilizers, lime, and inorganic NPSB fertilizers on nodulation, growth, and yield of soybean (Glycine max L. Merrill). Factorial combinations of four biofertilizer inoculants [without biofertilizer (B1), SB12 biofertilizer at the recommended rate of 500 g ha( -1) (B2), MAR1495 biofertilizer at the recommended rate of 500 g ha(-1) (B3) and SB12 plus MAR1495 biofertilizers at their recommended rates (B4); two lime rates named without lime (L1) and lime at 5 ton/ha (L2); two inorganic NPSB fertilizers NPSB at 9.5-23-3.5-0.05 (F1) and NPSB at 19-46-7-0.1 (F2) at their recommended rates for soybean] were laid out in a randomized complete block design (RCBD) with three replications. Effective nodules, leaf area index, and grain yield were collected and analyzed using SAS 9.1.3 version software. Results of the experiment showed that effective nodules per plant, leaf area index, and grain yield were affected by biofertilizers, lime, inorganic fertilizers, and their interactions significantly (p < 0.01) at both locations and years. Finally, the interaction of SB12 + MAR1495, lime at 5 t/ha and NPSB at 19-46-7-0.1, and the interaction of SB12, lime at 5 t/ha and NPSB at 19-46-7-0.1 gave the maximum grain yield at Assosa and Bambassi, respectively.