Effect of Rhizobium Inoculation, NPS Fertilizer and Vermicompost on Nodulation and Yield of Soybean (<i>Glycine max</i> (l). Merrill) at Bako, Western Ethiopia

Abstract

In Ethiopia, acidity-related soil fertility problems are the main production constraints, reducing productivity of major crops grown in the country. The experiment was carried out to determine influence of Blended NPS fertilizer, Seed Inoculation with Rhizobium Bacteria and Vermicompost (VC) application on soybean nodulation and yield of soybean. Factorial combinations of Rhizobium (uninoculated, inoculated), three VC levels (0, 1 and 2 t ha^-1) and three NPS levels (50%, 75% and 100% of 100 kg NPS ha^-1) were laid out in Randomized Complete Block Design (RCBD) with three replications. The results showed that the highest number of nodule per plant (32.0) and number of effective nodule per plant (31.4) were recorded at the combination of 2 tons VC ha^-1 and 75 kg NPS ha^-1 while the highest aboveground biomass (8953 kg ha^-1) was recorded at the combination of 2 tons VC ha^-1 with 100 kg NPS ha^-1. Likewise, the combination VC 2 tons ha^-1 with Rhizobium inoculation (TAL-379) gave the highest number of effective nodules per plant (26.3). On the other hand, three factors interaction of Rhizobium inoculation, VC and NPS rates significantly influenced the number of primary branches (NPB), number of pod per plant, seed yield and harvest index where the highest number of pods per plant (87.6), maximum seed yield (4180 kg ha^-1) and maximum harvest index (47%) were recorded from the plots treated with 100 kg NPS ha^-1 + 2 t VC ha^-1 inoculated with Rhizobium TAL-379 strain. Thus, considering the importance of integrated nutrient management in climate mitigation and adaptation; combined application of 2 t VC ha^-1 and 75 kg NPS ha^-1 inoculated with Rhizobium strain TAL-379 had resulted in better and optimum yield of 3870 kg ha^-1 and is tentatively recommended for use.