SEASONAL AND ANNUAL PATTERNS OF CLIMATIC ELEMENTS IN BENUE STATE AND THEIR IMPLICATIONS FOR YAM PRODUCTION

Abstract

Yam (Dioscorea spp.) is a critical food security crop in Benue State, Nigeria, yet production remains highly sensitive to climatic variability. This study examined the influence of climatic elements on yam growth and yield through analysis of thirty-five years (1988–2022) of climatological data. Climate elements; rainfall, maximum, minimum, and mean temperature, relative humidity, and solar radiation were analyzed using trend analysis and regression modeling to establish relationships with yam phenological development. Results revealed distinct seasonal patterns characteristic of tropical savanna climate, with rainfall concentrated between April and October (peak: 232.27mm in September) and a pronounced dry season from November to March. Annual rainfall exhibited high interannual variability (600–1600mm) with a statistically weak positive trend (R² = 0.055), indicating that year-to-year fluctuations dominate the rainfall regime. Maximum temperatures ranged between 33.0°C and 34.5°C, with peaks during March–April exceeding optimal thresholds for yam physiology, while minimum temperatures occasionally dropped below 20°C during harmattan periods, impeding metabolic processes. Relative humidity fluctuated clearly (50–95%), with extended high-humidity periods increasing pathogenic risks, while solar radiation variability approximately 4 -7 hours directly influenced photosynthetic capacity during tuber bulking phases. The study concludes that yam production is highly vulnerable to interannual climatic variability, particularly temperature extremes at critical phenological stages and erratic rainfall distribution. It is recommended that policymakers promote climate-resilient strategies including heat-tolerant yam varieties, adjusted planting schedules aligned with historical climatic windows, supplemental irrigation infrastructure, and humidity management practices to mitigate disease pressure and stabilize yields under increasing climate uncertainty.