Optimization of Vermicompost Rates based on the Nitrogen and Phosphorus Requirements of Bread Wheat (Triticum aestivum L.) in Northwestern Amhara, Ethiopia

Declining soil fertility and dependence on inorganic fertilizers threaten sustainable wheat production in Ethiopia. A three-year field experiment at Adet Agricultural Research Center evaluated the effects of integrating vermicompost (VC) with NP fertilizer on bread wheat productivity, soil fertility, and economic returns. The experiment used a randomized complete block design with five VC rates (0, 3, 6, 9, and 12 t ha^-1^) and three NP levels (0, 50%, and 100% of the recommended rate). The VC × NP interaction significantly affected biomass and grain yield. The highest biomass (6,859.6 kg ha^-1^) and grain yield (4,125.5 kg ha^-1^) were obtained with 9 t ha^-1^ VC plus 50% NP. Vermicompost also increased soil organic carbon. This treatment produced the highest net benefit (ETB 192,305.9 ha^-1^) and marginal rate of return (240.3%). Integrating VC with NP fertilizer enhanced wheat productivity, improved soil fertility, and increased economic returns under Ethiopian conditions.