Effect of N Rates and Seeding Rates on Agronomic Efficiency, Partial Factor Productivity, Grain Yield, and Grain Quality of Wheat under Irrigation in West Shewa, Ethiopia

Recently, wheat research has been established in Ethiopia for irrigated areas with the goal of developing high-yielding, higher-quality wheat cultivars. Nonetheless, two of the most crucial production variables are the N rate and the seeding rate, both of which need for the determination of ideal rates. Hence, a field experiment was conducted to determine the optimum N rate and seeding rate for bread wheat production under irrigated conditions in West Shewa highland areas during 2020–21 on different soil types. A factorial combination of seeding rates (125, 150, and 175 kg/ha) and N rates (0, 23, 46, 89, and 111 kg/ha N) with consideration of 19 kg of N content in 100 kg NPS fertilizer that was applied uniformly for all experimental plots except for those without fertilizer (zero rate plot) at sowing. The experiment was laid out in an RCB design with three replications. Most of the interactions were non-significant for grain yield and other parameters, while the main effects of seeding rates and N rates showed a significant effect on grain yield and other parameters measured. The highest test weight, agronomic efficiency, and partial factor productivity were recorded for the black soil type. Agronomic efficiency showed an unpredictable trend, while partial factor productivity showed a decreasing trend with an increasing seeding rate and N rate. Depending on the agronomic and economic analysis results, it can be concluded that a seeding rate of 175 kg/ha and an N rate of 111 kg/ha were found to be optimal for the production of the wheat variety ‘Kakaba’ under irrigation in the highlands of west Shewa.