A field experiment was conducted for three consecutive cropping seasons (2015-2017) on farmers’ fields in Welmera, Ada’a Berga and Ejere district of Oromiya Regional State. The objectives of this study were to evaluate the influence of organic and inorganic fertilizers on growth and yield of barley and soil chemical properties. The treatments included eleven selected combinations of organic and inorganic nutrient sources, including farmyard manure (FYM), vermicompost, compost, nitrogen (N), phosphorus (P) and boron (B). The design was randomized complete block with three replications. Results showed that barley yield and yield components, and soil chemical properties were significantly affected by the application of organic and inorganic fertilizer sources. The highest barley grain yield of 4277 kg ha-1 was obtained from the applications of half doses of vermicompost (3.8 t ha-1) based on the recommended N equivalent and half doses of the recommended N and P fertilizers (30 kg N ha-1 N and 34.5 P2O5 kg ha-1), followed by 3911 kg ha-1 due to the application of the full recommended inorganic N and P fertilizers (60 kg N ha-1 and 69 kg P ha-1). The highest biomass yield of 9937 kg/ha was obtained from the applications of the full recommended N and P rates (60 kg N ha-1 and 69 kg P2O5 ha-1). Application of organic fertilizer significantly improved soil organic carbon from 1.26 % to 1.56%, N from 0.14% to 0.23% and phosphorous from 7.84 mg kg-1 to 12.59 mg kg-1. The result also showed that the highest marginal rate of return was obtained from the application of 50% vermicompost based on N equivalent) + 50% N and P, which is economically the most feasible alternative on Nitisols of central Ethiopian highlands.
