Integrated soil fertility management using organic and inorganic fertilizers is recognized as absolute soil fertility management aims to increase yield, a better option for improving agronomic efficiency, providing a more balanced supply of nutrients, and saving the cost of production. Considering the importance of integrated soil fertility management for crop production an experiment comprised of eleven sole and integrated nutrient management practices was conducted on smallholder farmers' fields around Ambo for highland maize laid in a randomized block experimental design with three replications. Yield and yield components of the highland maize variety (Jibat) were significantly affected by the sole and integrated use of vermicompost and NPS fertilizer rate. Significantly higher (6187 kg ha-1) was obtained with the application of 92/69/30 kg NPS ha-1 followed by (5193 kg ha-1) with 50:50 vermicompost based on N equivalency and NPS fertilizer rate. Application of 92/69/30 kg NPS ha-1 gave the highest net return of EB 32265 with the highest marginal rate return of 713 % followed by the net return of EB 27167 and marginal rate return of 295 % from the application of 50:50 % recommended NPS with vermicompost based on N equivalency in Vertisols of Ambo. Therefore the application of 92/69/30 kg NPS ha-1 and 50:50 % recommended NPS with vermicompost based on N equivalency produced better grain yield and was economically feasible and recommended for highland maize production in Vertisol of Ambo and similar agro-ecologies.
Keywords: Integrated soil fertility management, NPS, vermicompost, highland maize, variety
