Agronomic and Economic Parameter Estimates of Cocoyam as Influenced by Fertilizer and Environment

The effects of fertilizer and environment on agronomic traits and economic parameters in cocoyam were assessed at the Njala Agricultural Research Centre experimental site during the 2014/2015 and 2015/2016 cropping seasons. The fertilizer types used were 200 kg ha^–1 NPK 15-15-15, 2000 kg ha^–1 Rabbit Manure (RM), and no fertilizer (control). The trial was established in the open field and mango tree forest environments using a randomized complete block design. Findings revealed that fertilizer and environment significantly (p<0.05) affected cocoyam leaf area, plant span, plant height, disease severity, cormel and corm yields, dry matter contents in leaf, petiole, corm, cormel and root organs, and economic parameters. Application of 2000 kg ha^–1 RM (6.75 t ha^–1) and 200 kg ha^–1 NPK (5.65 t ha^–1) had significantly (p<0.05) highest cormel produced in the forest environment comprising 60% forest cover than those grown in the open field. Fertilizer application and environment significantly (p<0.05) affected the Partial Factor Productivity (PFP) and Agronomic Efficiency (AE) of cocoyam corm and cormel. The PFP and AE values were higher for cormels and corms produced in the open field and forest environments using 200 kg ha^–1 NPK 15-15-15 than those obtained using the 2000 kg ha^–1 RM. The significant influence of fertilizer and environment on traits suggests that increasing yields and maximizing profits require the use of appropriate production environments, fertilizers, and improved farming practices that could be exploited for increased productivity of cocoyam.