Temperature and rainfall are important variables that affect maize yield, and as such this study aimed at evaluating the impact of onset, cessation of rainfall and temperature on maize yield in Akure. To achieve this objective, climatic parameters comprising daily rainfall and temperature (maximum and minimum temperature) 1981-2016 for Akure, were obtained from the archives of the Nigerian Meteorological Agency, NiMet. Annual maize yield data for the same period 2000-2016 were obtained from Ondo State Agricultural Development Programme. Walter’s method, as modified by [1], was then used to determine the onset, cessation and length of growing season. The significance of the annual trend of these climatic parameters was also tested using an approach involving z-test and p-value analysis. Likewise, the significance of all the climatic parameters contributing to maize yield was also determined based on the p-value approach under a null hypothesis. The coefficients of determination (R2) and Pearson correlation coefficient (r) in relation to the SLR and MLR models were calculated. The result showed a slight decreasing trend of rainfall, increasing trend of maximum, minimum and maize yield. Their associated p-values are 0.6925, 0.5794, 0.5136 and 0.0630, which showed that the trend over the years was not statistically significant at the 1%, 5% and 10% levels; however maize yield was significant at 10% significant level. The mean onset, cessation and length of growing season for Akure were 8th March ± 9, 21st October ± 21 and 239 days ± 27 days. The relationship between maize yield and all climatic variables in association with SLR model showed that rainfall was the major contributing variable to maize yield in Akure, Ondo State at all significant levels (p-value (0.009539) < 0.01, 0.05 and 1 r = 61%, R2 = 37%). The p-value in association with MLR model, also showed that rainfall was significant at 5% and 10%. P (0.019412) < 0.1 and 0.05, r = 72%, R2 = 51%.
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