Abstract:
Climate variability has been shown to have significant impacts on global and
regional food production particularly the common staple food crops in
tropical sub-humid climatic zone. However, the extent and nature of these
impacts still remain uncertain. This study investigates the impacts of the
variability of climatic variables on some food crops grown in the major
ecological zones of Nigeria (rainforest, guinea savanna, sudan savanna and
sahel) using Stepwise Multiple Regression Analysis and variability indices.
Meteorological (monthly rainfall, minimum temperature, maximum
temperature, sunshine hours and relative humidity) and crop yield data
(yam, maize, cowpea, millet and sorghum) from 1985 to 2006 were used for
the study. The magnitude of the coefficients of correlation (r) was taken as
a first approximation of the impacts using the bivariate correlation analysis.
Variability indices results (z-value) established the fact that cumulative
climate variability particularly rainfall during growing season are significant.
The analysis further shows the negative impacts of unfavourable climate
conditions that resulted in reduced crop yields in the 1980’s to 1990’s period.
The predictive model generated for the crops were significant at α ≤ 0.05 (pvalue)
and showed that April, June and September rainfall as well as
sunshine duration (SS) during the growing season were the most significant
yield predictors of the crops studied. The statistical models further showed
that at least 50% of the variation in the yield of crops studied in all the zones
could be explained by the predictor variables.