Response of Field Pea (Pisum sativum L.) to Rhizobium Inoculation and NPS Fertilizer Applications in Western Ethiopia

Background and Objective: The low attention of smallholders and low soil fertility are the main reasons for the low productivity of field peas in Western Ethiopia. Thus, a study was conducted to investigate the effects of Rhizobium inoculation and NPS fertilizer rates on nodulation, yield and yield components of field peas and to identify economically profitable treatments that can maximize the productivity of field peas in the study area. Materials and Methods: Two levels of Rhizobium inoculation (No inoculation and EAL301), two field pea varieties (Jidha and Lammiif) and five rates of NPS fertilizer (0, 25, 50, 75, 100 kg NPS ha^–1) were arranged in Randomized Complete Block Design (RCBD) with three replications and all collected yield and yield related parameters were analyzed using R statistical software. Results: Phenological and growth parameters were influenced by the main effects of varieties whereas harvest index was influenced by varieties and NPS fertilizer rates. On the other hand, pod numbers per plant and seed yield were significantly affected by the three-way interaction of Rhizobium, varieties and NPS fertilizer rates. The highest grain yield (2800 kg ha^–1) was obtained from the application of 100 kg NPS ha^–1+Rhizobium inoculation which was followed the by application of 100 kg NPS ha^–1 for the lammiif variety. The highest net benefit (93490 and 82290 Birr ha^–1) and MRR (1596.0 and 1593.3%) were recorded from the application of 100 and 100 kg NPS ha^–1+EAL301 strain. Conclusion: Thus, the application of 100 kg NPS ha^–1 only or the application of 100 kg NPS ha^–1+EAL301 strain inoculation is recommended for field pea production in western highlands of Oromia and similar agro-ecologies.