Assessing Climate and Weather Patterns on Cocoa Yield Trends in Oyo State, Nigeria

Climate variables like temperature and rainfall are crucial direct inputs to the agricultural industry; therefore, any changes or fluctuations in these variables will inevitably have a big impact on crop production. Climate change and extreme weather events are already leading to low yields of crops in developing countries like Nigeria. Data were collected at the meteorological station located at International Institute of Tropical Agriculture (IITA) and Oyo State Cocoa Development Unit, Ibadan for Thirty years (1985-2014). Non-parametric Mann-Kendall trend analysis and standard parametric methods of linear and quadratic regression analysis were performed on the variables in order to determine the trend direction and magnitude of change over time together with the Sen.’s slope. Annual trend statistics for cocoa yield and climatic variables were analyzed in Oyo State, South Western Nigeria, using the Mann-Kendall test for trend and Sen’s slope estimate using the meteorological and cocoa yield data. The annual cocoa yield showed a significant increase at the rate of 468.02 tons/year (P<0.001) in Oyo State while there was an insignificant increasing trend in the rainfall pattern at the rate of 0.32 mm/yr. We observed a significant increase in annual Tmax, Tmin, and Tmean at a rate of 0.02/yr. it was also observed that rainfall has the most grievous impact on cocoa yield among all climatic variables. However, the objective of the study is to assess climate and weather patterns effects on cocoa yield trends in Oyo state, Nigeria. Farmers should take measures for effective adaptation strategies to mitigate the impact of future change in climate variable on cocoa yield in the study area.