Evaluation of best performing indigenous Rhizobium strains on productivity of faba bean in Gumer District, south-eastern Ethiopia

Abstract

Biological fixation of atmospheric nitrogen by legumes is a known way to recycle nitrogen into a plant-available form. The efficiency of nitrogen fixation depends on the legume genotype and requires a host-specific Rhizobia strain for nodule formation and yield enhancement. A field experiment was designed to evaluate performance of Rhizobium strains on yield and yield components of faba bean under rainy conditions during two consecutive main growing seasons (2019 and 2020). Experiments consisted of a control, 121 kg NPS ha^-1, FB 04, FB 1018 and FB 1035, each strain treated separately with 60 kg ha^-1 nitrogen, phosphorus and sulfer (NPS) and Triple superphosphate (TSP) and placed in a randomized complete block design with three replications. Rhizobium inoculation showed a highly significant (p ≤ 0.05) effect on yield and yield attributes compared to un-inoculated (negative control) treatment. Over the years, the results showed that the inoculated plants gave a significant increase (p ≤ 0.05) in nodule number and a benefit in grain yield compared to the un-inoculated plants (negative control). Among inoculated treatments numerically, the highest yield (5.87 t ha^-1) was recorded with FB 1018 inoculated together with 60 kg ha^-1 TSP  compared to those without inoculation (absolute control) which gave 2.48 t ha^-1. All Rhizobia inoculate of faba bean showed better nodule formation to increase yield and it is recommended that farmers in the study area and similar agro-ecologies use this technology.

Keywords: Faba bean, Nodulation, Rhizobium Strains, Yield