Effect of Agroforestry and Conventional Cropping Systems on Potato ( Solanum tuberosum L.) Productivity and Pest Management in Menoua Division, West Cameroon

Abstract

This study assessed the agronomic performance, pest and disease dynamics, and economic profitability of three potato production systems—conventional system with chemical inputs (CS), agroforestry system with Gliricidia sepi um biomass (AFS), and a control system without any inputs (CP)—in the Menoua Division of West Cameroon. A randomized complete block design was employed to evaluate growth parameters, tuber yield, pest and disease incidence, and financial returns over a single cropping cycle. The conventional system produced the highest tuber yield (38.97 t/ha), followed by AFS (25.42 t/ha), while the control system yielded the least (10.53 t/ha). Growth parameters, including plant height, crown diameter, leaf area, and number of lateral branches, were significantly superior under CS, although AFS gradually caught up at mid-growth stages due to sustained nutrient release from Gliricidia biomass. Downy mildew ( Phytophthora infestans ) severity and incidence were effectively suppressed in both CS and AFS, with no significant differences observed between them at 76 days after sowing (DAS), while CP exhibited the highest disease pressure. For insect pests, AFS consistently outperformed both CS and CP in minimizing incidence and severity of leaf-eating caterpillars and whiteflies. While CS achieved early pest suppression through chemical control, its effectiveness declined over time, resulting in pest levels similar to or exceeding those of the control by late growth stages. Economic analysis revealed that CS generated the highest absolute profit but incurred the highest production costs. In contrast, AFS demonstrated highly competitive profitability (324.61%) and strong value-cost ratio (VCR 4.24), offering substantial economic benefits while reducing dependence on costly external inputs. These findings highlight agroforestry as a sustainable and economically viable alternative for smallholder potato producers, delivering strong agronomic performance, effective pest management, and improved financial returns under resource-limited conditions.