Effects of Combined NPS Fertilizer and Goat Dung on Onion (Allium cepa L.) Growth and Yield in the Tanqua Abergelle District, Ethiopia

Onion production is mostly facilitated by the Gereb Giba small-scale irrigation system, making it one of the major vegetable crops. Inadequate soil fertility management techniques and nutrient deficits are the primary causes of the research area's decreased onion crop productivity. As a result, fertilizer applications are a crucial input to boost onion yields, with the rate of application primarily determined by the soil's fertility. The research was conducted with the intention of the objective is to assess the impact of NPS and goat dung fertilizer combinations on onion variety yield and yield-related characters, as well as the physicochemical parameters of the soil and the economic feasibility of combining goat dung and NPS fertilizer on onion. To implement the study, a randomized complete block design with sixteen treatments was employed. Results of the analysis of variance indicate that there is a significant difference between the 16 treatments for the combined application of inorganic (NPS) and organic (goat dung) fertilizers in response to onion. The target area's soil textural class is sandy clay loam, which has low levels of organic carbon and total nitrogen. The study's findings indicated that the application of 84 kg N ha-1+76 kg P2O5 ha-1+14 kg sulfur ha-1 with 7.5 t ha-1 organic (15.1 t/ha) was superior in terms of marketable yields, as was the case with 63 kg N ha-1+57 kg P2O5 ha-1+10.5 kg sulfur ha-1 (14.6 t/ha) and 84 kg N ha-1+76 kg P2O5 ha-1+14 kg sulfur ha-1 fertilizer (14.8 t/ha) with 15 t ha-1 goat dung. On the other hand, 21 kg N ha-1+19 kg P2O5 ha-1+3.5 kg sulfur ha-1 fertilizer with 3.75 t ha-1 goat dung (11.15 t/ha) was found to be inferior. Therefore, based on the cost-benefit analysis and its production, farmers in the Gereb giba area and other similar agro-ecologies are advised to apply 15 t ha-1 of goat dung along with 63 kg N ha-1, 57 kg P2O5 ha-1, and 10.5 kg sulfur ha-1 of inorganic fertilizer (14.6 t/ha). This combination is both economically feasible and highly recommended.