Grain Yield and Yield‐Related Traits of Sorghum ( <i>Sorghum bicolor</i> (L.) Moench) as Influenced by Integrated Application Rates of Inorganic Fertilizer and Farmyard Manure in Oromia, Ethiopia

Sorghum is among the major crops in Ethiopia due to its numerous benefits as both food and livestock feed, which is grown in a wide range of agroecologies throughout the country. Regardless of its benefits, its productivity is constrained by the decline of soil fertility and age‐old cultivation practices. The farmers in the area were also deprived of resources and incapable of meeting the nutrient requirements of their crops through inorganic fertilizers due to the high cost associated with them. In this view, a field experiment was conducted in 2022 and 2023 at Bako, Gute, and Bilo‐Boshe experimental sites, western Ethiopia, to determine the optimum integrated rates of NPSB and N fertilizer, and farmyard manure for sorghum production. The trials were laid out in a randomized block design with a factorial arrangement in three replications. The treatment consisted of four NPSB/N levels (25%, 50%, 75%, and 100% of the previously recommended rates) and four rates of farmyard manure (0, 3, 6, and 9 t·ha −1 ). The analysis of variance was done using Genstat software, and the Duncan multiple range test was used to compare treatment means. The result of the analysis of the variance revealed that the interaction of various levels of applied NPSB/N and farmyard manure rates significantly affected the grain yield, dry biomass, and the harvest index across locations and seasons. The highest grain yield (5.4 t·ha −1 ) with an acceptable marginal rate of return (MRR) of 192.1% and a value‐to‐cost ratio of ETB 8.7 per unit investment was achieved when 75% NPSB/N combined with 3 t farmyard manure ha −1 rates. Therefore, the combined use of the aforementioned rates was agronomically and economically feasible and advised for improved sorghum production in the study areas.