Response of Maize (Zea mays L.) Yield to Climatic Elements in a Rainforest Agro-Ecology

Abstract

Owing to the prevailing climate change which has drastically reduced the duration of the wet season that supports naturally cultivated maize in a typical rainforest ecology of Ife, Southwestern (SW) Nigeria, this study determined the climatic factor(s) favouring maize yield in the agro-climatic zone. Grain yield data obtained from five maize varieties grown in 42 environments, at Ife – Teaching and Research Farm of Obafemi Awolowo University, along with weather data captured electronically and automatically at the Farm, were analyzed using variance, correlation, regression, and path coefficient analyses. Grain yield was a significant correlate of solar radiation (r = 0.58**) and soil temperature (r = 0.39*). Subsequent stepwise multiple regression analysis isolated total solar radiation as the single most important causal factor for increased yield, albeit, with a low R² = 34%. Fitting the regression model up to quartic level did not increase the R² value. Other climatic factors affecting grain yield included minimum temperature, heat unit, and maximum air relative humidity, all acting indirectly through total solar radiation. At this and similar agro-ecologies, maize must be planted from March to early April and late July to August for the early and late season crops, respectively.