Asian Journal of Research and Review in Agriculture

The application of nitrogen fertilizer should be based on soil test results and expected nutrient requirements of the crop, due to its dynamic nature in the soil-plant system and its potential negative environmental impacts. An on-farm trial was conducted during the 2022 and 2023 main cropping seasons at Gedeb woreda in Gedeo Zone, South Ethiopia. The objective was to evaluate wheat varieties and N fertilizer rates on yield and yield components and determine the economically optimum N rate for the study area. The trial was conducted using a randomized complete block design with three replications. Five levels of varieties, namely Shorima, Wane, Deka, Lemu, and Shaki, and five levels of nitrogen fertilizer rates (0, 23, 46, 69, and 92 kg nitrogen ha⁻¹) were used for the study. The main effect of variety and nitrogen rate was significant (p < 0.05) for plant height, number of spikes per m², number of tillers per m², thousand seed weight, seed number per spike, and grain yield ha⁻¹. However, the interaction result of the varieties and nitrogen had no significant effect on all measured parameters. The pooled data result showed that Lemu produced the maximum grain yield of 3807.8 kg ha⁻¹, while Shaki and Wane produced the lowest grain yield. Likewise, the application of N fertilizer up to 92 kg N ha⁻¹ can increase wheat yield, but the rate had no significant difference with 69 kg nitrogen ha⁻¹. The profitable rate for wheat production, considering both yield increase and fertilizer costs, was 46 kg nitrogen ha⁻¹. In addition, a simple correlation analysis was also made to see the relationships between grain yield and yield components. Therefore, the studied yield attributes had shown a positive and significant correlation with grain yield. Overall, the Lemu variety and 46 kg nitrogen fertilizer rate ha⁻¹ were selected to achieve better yield and profit. Therefore, it can be suggested for large-scale wheat production.