Effects of cropping system and fertilizer application on growth and yield of sorghum and groundnut in Igbariam, Nigeria

Abstract

This study evaluated the effects of cropping system and Nitrogen: Phosphorus: Potassium (NPK) fertilizer application on the growth and yield of sorghum (Sorghum bicolor L. Moench) and groundnut (Arachis hypogaea L.) under sole and intercropping systems in Igbariam, southeastern Nigeria. Field experiments were conducted during the 2024 and 2025 cropping seasons using a factorial arrangement in a randomized complete block design with three replications. Four NPK (12:12:17 + 2MgO) fertilizer rates (0, 100, 200 and 300 kg ha⁻¹) were evaluated under sole and intercrop production systems. Data collected on growth and yield components were subjected to analysis of variance, and treatment means were separated using the Least Significant Difference test at the 5% probability level. Results obtained showed that the cropping system and fertilizer application significantly influenced the growth and yield of both crops. Sole sorghum generally exhibited superior vegetative growth and yield attributes compared to intercropped sorghum, while sole groundnut consistently outperformed intercropped groundnut in plant height, leaf production, and reproductive development. Fertilizer application significantly enhanced crop growth and yield, with the greatest responses generally recorded at 200-300 kg ha⁻¹. Although intercropping resulted in some competitive effects that reduced crop performance, adequate fertilizer application partially mitigated these effects and improved crop productivity. These results indicated that balanced nutrient management is essential for sustaining productivity in sorghum–groundnut intercropping systems. Under the conditions of this study, application of 200–300 kg ha⁻¹ NPK (12:12:17 + 2MgO) is recommended for improved growth and productivity, particularly where sole cropping or well-managed intercropping systems are practiced.