Effect of Sulfur and Bradyrhizobium Inoculation on Nodulation and Yield of Soybean (<i>Glycine max</i> L.) on Nitisols of Southwestern Ethiopia

Abstract

A field experiment was conducted at Jimma Agricultural Research Center (JARC) during 2017/18 growing season to evaluate the effect of integrated use of Bradyrhizobium strain and sulfur fertilization on nodulation and yield of soybean. The experiment consisted of four levels of S (0, 20, 30 and 40 kg ha^-1) and three Bradyrhizobium strains (MAR-1495, SB-12 and Murdock) arranged factorially in completely randomized block design (RCBD) with three replications. Grain and straw yield increased due to inoculation of Bradyrhizobium strain whether used alone or in combination with S. Nodulation, parameters (nodule number per plant and nodule dry weight) and number of pods per plant were highly significantly influenced due to combined use of Bradyrhizobium strains with sulfur fertilization. The yield and yield components namely (grain yield, hundred seed weight, biomass yield and harvest index) were highly significantly (P < 0.01) affected by individual application of sulfur and inoculation of Bradyrhizobium strains alone. Accordingly, the highest grain yield (1496.35 kg ha^-1) was obtained from application of S at a rate of 30 kg ha^-1 corresponding 30.96% yield advantages compared with control and 1548.55 kg ha^-1 grain yield was recorded due to inoculation with Murdock strain corresponding to 30.32% increase over MAR-1495 strain. The results clearly suggested that proper application of S along with Bradyrhizobium strain affect nodulation, grain and straw yield of soybean.