Weather variability in derived savannah and rainforest agroecologies in Nigeria: Implications for crop yields and food security

Abstract

Weather variability and its effects on agricultural and food systems are burgeoning global concerns. This study examined the effects of weather variability in the derived savannah and rainforest agroecologies, on crop yields in Southwest Nigeria, and what it portends for food and nutrition security in the region. The trends in the distribution of rainfall and temperature were analysed using the Sens method. The effects of weather variability on crop yield and inferences on what it portends for food security were determined using a stepwise regression model. The results revealed that rainfall fluctuations decreased the yields of cassava (Manihot esculenta) and yam (Dioscorea spp.) in the derived savannah; while a decrease in temperature may support improved yields for maize (Zea mays), sorghum (Sorghum bicolor) and cowpea (Vigna unguiculata). The increase in yields of cocoa (Theobroma cacao) and cocoyam (Colocasia esculenta) would be hampered by increasing maximum temperatures in the rainforest agroecology. Increasing rainfall and temperature would impact warmer conditions that support rapid crop putrefaction, flooding, droughts, challenging postharvest crop management, pest and disease proliferation, and ultimately, reduced crop yields. On the other hand, perpetually low rainfall and temperature conditions will cause poor seedling emergence and growth, seed and total crop loss. It is, therefore, imperative that effective climate adaptation and mitigation mechanisms be put in place across the agroecologies in the region.