Modelling the Impacts of Climate Change on Soybeans Water Use and Yields in Ogun-Ona River Basin, Nigeria

Abstract

African countries such as Nigeria are anticipated to be more susceptible to the impacts of climate change due to reliance on rainfed agriculture. In this regard, the impacts of climate change on crop water requirements (CWR), yields and crop water productivity (CWP) of soybean in the Ogun-Ona River Basin, Nigeria, were evaluated for the baseline period (1986–2015) and future period (2021–2099) under Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios using AquaCrop Version 6.1. Future climate projections from the Swedish Meteorological and Hydrological Institute’s climate models (HadGEM2-ES and RCA4) were used in simulating the future scenarios. The results show that for the baseline period, CWR and yield are increasing while CWP shows a slight increase. For the future period, the CWR is projected to fluctuate and depend on the rainfall pattern. Meanwhile, carbon dioxide fertilization has positive effects on yield and is projected to increase up to 40% under RCP 8.5. The results of this study certainly offer useful information on suitable adaption measures which could be implemented by stakeholders and policymakers to improve soybean productivity in Nigeria.