Geospatial Analysis of Rainfall and Temperature Variations Effect on Maize (Zea Mays) Yield

Climatic variation results from the gradual warming of our planet, which accounted for the variability of the weather globally. This variation in turn affects agricultural crop production negatively; this often necessitates price increase and hence food scarcity. Maize is an important food in Nigeria, especially in the south-west Nigeria. Maize farmers are in need of data to better plan crops planting and monitor rate of yield. Thus, the study examined the relationship between the inter-annual climate variability (temperature and rainfall) and the maize yield in south-western states of Nigeria. Annual maize yield data for years 1991–2007 were collected from the Federal Ministry of Agriculture, Nigeria, while temperature and rainfall data were obtained from the Nigerian Meteorological Station. Analysis of the relationship between climate variation of temperature, precipitation on maize yield and maps of the respective parameters was produced using GIS for selected years. The results of the work include production of geospatial variation maps of the rainfall, temperature and maize yields and the correlation of the variables in study area. Ekiti State had the highest rainfall value of 182.86 cm, while Ogun State had the least rainfall value of 110.81 cm. Projecting for the year 2017, Ondo and Ekiti states would have a joint highest rainfall value of 190.13 cm while Ogun State may have rainfall value of 110.25 cm. For temperature, Ogun State had the highest temperature value of 32.21 °C while Lagos State had the lowest temperature value of 31.39 °C. By prediction, Ogun State will have mean annual temperature of 32.08 °C by the year 2017, while Lagos State would have the least temperature value of 31.43 °C. Mean annual maize yield on temperature-based is highest for the year 2012 at Osun State (1.81 tonne value) and lowest at Ogun (1.43 tonne). Mean annual maize yield, however, varied from state to state. By the year 2017, mean annual maize yield would decline to 1.46 tonne for Osun State and least in Ogun State with 1.16 tonne. The study depicted a general pattern, but the results change from state to state. The findings from the study will help governments and farmers to better plan crops production activities in order to address the problem of increasing food security.