Yield and yield component responses of sorghum (Sorghum bicolor (L.) Moench) varieties to nitrogen application in West Armachiho and West Belesa, North Western Ethiopia

Abstract

Sorghum is the most important cereal crop grown in Ethiopia. However, the average productivity in the study areas is very low. A field experiment was conducted in West Armachiho and West Belesa, during the 2023 main cropping season to evaluate the effect of nitrogen rates and sorghum varieties on crop productivity. Treatments consisted of a factorial arrangement of four levels of nitrogen fertilizer rates (0, 46, 92, and 138 kg N ha-1) and three sorghum varieties (Melkam, Girana-1, and local). The experiment was laid out in a randomized complete block design with three replications. The collected data were analyzed using R Software (R Package, Version 4.5), and significant treatment means were compared using the LSD test. Significant effects of nitrogen rates and varieties were observed on sorghum yield and related parameters. Most yield-related parameters showed the highest value at combination of Melkam variety and 138 kg N ha⁻¹ application. The interaction effect of N-rates and varieties was significant (p=6.22×10⁻⁴) on grain yield. The highest grain yield (5.3 t ha⁻¹) was recorded from 138 kg N ha⁻¹ applied to the Melkam variety. The maximum net benefit (USD 2,901.8) with a 365.3% Marginal Rate of Return (MRR) was obtained from 138 kg N ha⁻¹ applied to the Melkam variety. Therefore, based on the agronomic performance and partial budget analysis results, 138 kg N ha⁻¹ with the Melkam variety increased sorghum yield, while integrated soil fertility management, including crop residue retention, is recommended for fertility-depleted soils in West Belesa, West Armachiho, and similar agroecologies.