Impacts of rainfall and temperature variation on maize (Zea mays L.) yields: A case study of Mbeya Region, Tanzania

Abstract

Based on the multiple regression model the impacts of rainfall and temperature on maize (Zea mays L.) yields in Mbeya region have been analyzed. Overall, findings revealed that the seven selected variables, that is, January maximum temperature, February maximum temperature, April maximum temperature, Rainfall from February to April, Rainfall during growing season, December rainfall and October maximum temperature influenced maize yields in the region by 65.4%. Diversely, the results showed 34.6% wasn’t explained by the model, meaning that there are other factors apart from temperature and rainfall could be used to explain the variation of maize (Z. mays) yield in the region. Furthermore, taking 1990 -2012 as baseline period, the model projection for a period of 2020-2042 shows that maize (Z. mays) yield may change from 1.5% to 2.3%, 2.6% to 3.6% and 2.4% to 3.5 %, as a result of separate future influence of 10% decrease in rainfall, 1⁰C raise in temperature and combined influence of both temperature and rainfall change, respectively. Nevertheless, the findings from this study, reveals that Mbeya region may still be potential maize (Z. mays) growing region in the prescribed period provided the magnitude change of both future rainfall and temperature hold and other factors not explained by the model do not change significantly. Therefore, the government must focus to conduct more research on uses of appropriate maize (Z. mays) varieties to obtain the maximum maize (Z. mays) crop yield in the region.