Effects of Selected Organic Amendments on Growth and Yield of Bambara Groundnut (Vigna subterranea L.) in Abuja, Nigeria

Abstract

Objective: This study was conducted to evaluate the comparative effectiveness of three organic materials—cassava peels (E1), neem leaves (E2), and poultry manure (E3)—on growth characteristics and yield performance of three Bambara groundnut (Vigna subterranea L.) varieties: Maibergo (V1), Karu (V2), and Giiwa (V3) under field conditions in Abuja, Nigeria. Methods: Field trials were conducted at the Teaching and Research Farm of Yakubu Gowon University, Abuja, using a Randomized Complete Block Design (RCBD) with three replications across 2024 and 2025 planting seasons. Growth parameters (plant height, leaf area, number of branches) and yield components were measured at 4, 8, and 12 weeks after sowing (WAS). Results: Cassava peel treatment significantly enhanced vegetative growth, producing the highest mean plant height (27.67 cm) and leaf area (21.68 cm²) at 12 WAS. Among varieties, Maibergo consistently showed superior performance with maximum plant height (27.68 cm) and leaf area (30.86 cm²) at 12 WAS. Significant variety × extract interactions (p ≤ 0.05) were observed, with the V1E1 combination (Maibergo + cassava peel) achieving optimal plant height (28.93 cm). Poultry manure extract significantly increased branching, particularly benefiting the Giiwa variety at 4 WAS and 12 WAS. Most importantly, cassava peel amendment increased pod yield by 30% compared to untreated controls, demonstrating superior economic returns. Conclusion: Cassava peel emerged as the most effective organic amendment for enhancing Bambara groundnut production, offering dual benefits of improved vegetative growth and substantial yield increases. The significant variety-specific responses indicate that targeted organic amendment strategies can optimize production outcomes. These findings provide practical guidance for smallholder farmers seeking sustainable alternatives to synthetic fertilizers, supporting both food security and environmental sustainability in sub-Saharan African agricultural systems.