Sigaye MH, Nigussei A , Lulie B , Mekuria R and Kebede K
The study was carried out to determine the influence of organic and inorganic fertilizers on maize yield and soil fertility; to determine economically optimum organic and inorganic fertilizer combinations for maize production. The study was performed in a randomized complete block design consisting of 10 treatments and 3 replications. The treatments were: Control, 100% of R-NP (138 N and 92 P), 100% of vermicompost, 100% of conventional compost, 25% R-NP +75% of vermicompost, 50% of R-NP + 50% of vermicompost, 75% of R-NP+25% of from vermicompost, 25% of R-NP +75% of conventional compost, 50% of R-NP+50% of conventional-compost, 75% of R-NP +25% of conventional-compost. All rates of vermicompost and conventional compost were applied based on N equivalence. Results indicate that applications of inorganic fertilizers with a combination of organic source fertilizers were increases maize yield and yield components and improves the nutrient status of the soil. The highest maize grain yield (7494.3 kg ha-1) and above-ground biomass yield (18718.0 kg ha-1) was obtained from the applications of 50% recommended NP fertilizer plus 50% vermicompost which is based on the recommended N equivalent respectively. Similarly, we found that a combination of both inorganic and organic fertilizers application also is the best strategy to improve major soil nutrients, maintain soil fertility. The economic analysisrevealed thatthe highest net benefit of (108,872.00 ETB ha-1) was obtained from the application of 50% recommended NP fertilizer plus 50% vermicompost. Yet, the lowest yield and net benefit value were attained from the control or unfertilized plot. Therefore, this study suggests that an appropriate proportion of organic fertilizer with inorganic fertilizer not only for higher yield maize production with an assurance of potential economic returnsto the small hold farmers but also improve and maintain the soil fertility and should be adopted with similarsoil type and agro-ecologies.