Evaluation of Nitrogen-fixing Inoculants for Enhanced Production of Groundnut (<i>Arachis hypogea L.</i>) in Pawe District, North Western Ethiopia

Groundnut (Arachis hypogea L.) cultivation in Ethiopia is dominated by smallholder farmers who use little or no inputs, often resulting in low yields. The use of effective rhizobia isolates was considered an ecologically and environmentally sound approach for groundnut production. A field experiment was conducted in the Pawe district in Metekel zone, Benishangul Gumuz National Regional State (BGNRS) during the 2022 cropping season on five farmers’ field to evaluate the effectiveness of nitrogen-fixing inoculants of groundnut, namely, Dibate-modermo. The experiment consisted of four treatments; T1=negative control (without chemical fertilizer and inoculant), T2= NPS fertilizer at a rate of 100kg ha<sup>-1</sup>, T3=NEM isolate, and T4=Dibate-modermo isolate. It was laid out in a randomized complete block design with five replications. Five composite soil samples were collected from 0-20 cm depth before planting and analyzed for selected soil properties. The treatments were not replicated per farm; instead, farmers were used as a replicates. Results of the analysis of variance (ANOVA) indicated that plant height, number of nodules, branches, seeds, and pods per plant, haulm yield, and grain yield were significantly affected by the application of treatments. The highest grain yield was obtained with inoculation of Dibate-modermo isolate, which increased grain yield by 49.9% as compared to the untreated plots. Similarly, this isolate resulted in the highest net benefit (75,460.8ETB ha<sup>-1</sup>) with acceptable MRR (2667.7%). Hence, mass production and utilization of Dibate-modermo isolate is recommended for enhanced production and improved productivity of groundnut in the area.