Climate Change Effects On Maize (Zea Mays) Production In Nigeria And Strategies For Mitigation

Although Nigeria is the leading producer of maize in Africa, effects of climate change especially high temperature, and irregular changes in precipitation are critically limiting its crop yield. In order to sustain high crop yield of maize in spite of the climate change and the rapid increasing population in the country, there is urgent need to study the responses of maize crop to variables of climate change so as to design effective coping strategies. The objective of this study therefore was to study the impacts of key climatic variables on maize production in Nigeria and to identify effective mitigation and coping measures. Secondary data on the trend of maize production and maize yield responses to changes in climates across five agro-ecological zones in Nigeria were studied. The result showed that the predicted maize yield at current CO2 level decreased with increase in temperature in all the agro-ecological zones. The reduction in yield was more pronounced in the humid forest and semi-arid agro-ecological zones with 18% and 13% yield reduction, respectively while the least was observed in the derived and southern guinea savannas with 7% yield reduction. Doubling the current level of CO2 showed increases in yields at low temperature change of between 1-2oC, but the yield was consistently reduced in all the zones with higher temperature changes of between 3-4oC. Changes in rainfall amount of +20% when the current CO2 was doubled did not have any significant impact on maize yield. Increase in temperature showed reduction in the days to flowering and maturity across the agro-ecological zones. The simulated yields and days to physiological maturity of the four maize cultivars (early, medium, late and very late maturing varieties) under the current and doubled CO2 using UKMO (United Kingdom Meteorological Office) scenario showed that the varieties with longer days to maturity recorded higher crop yield consistently in all the agro-ecological zones. This suggests that the yield reducing tendencies of maize in a hotter climate as in Nigeria could be mitigated through appropriate choice of cultivar, adjustment of management practices and time of planting, provision of adequate irrigation facilities among other recommendations made in this study.