Soil degradation poses a major challenge to sustainable yam (Dioscorea rotundata) production in tropical regions due to continuous cultivation and declining soil fertility. This study presents the first field-based two-year factorial evaluation of cocoa pod husk biochar (CPHB) combined with poultry manure (PM) on yam performance in a degraded tropical Alfisol at Owo, southwestern Nigeria.
The experiment was arranged in a factorial design with three CPHB rates (0, 15.0, and 30.0 t ha-1) and three PM rates (0, 10.0, and 20.0 t ha-1), replicated three times over two consecutive years (2023 and 2024). Results showed that CPHB and PM, applied singly or in combination, significantly (p