Modeling Impacts of Climate Change on Bread Wheat (Triticum Aestivum l.) Productivity in Bale Highlands, South Eastern Ethiopia: Case of Robe Area

Abstract

Wheat is one of the food security crops in Ethiopia which is critically sensitive to the impacts of climate change. However, the factors of climate change are very local; hence a local-level and crop-specific understanding of the impact is extremely important. With this understanding, a study is conducted at Sinana district in Bale Highlands to model the impacts of climate change on bread wheat production and analysis under future climate scenarios. Historical climate data (1984-2016), projected climate data downscaled using the ensemble of all GCMs, were analyzed to understand the local level climate change. The future climate is analyzed regarding changes in annual rainfall, seasonal rainfall, and monthly rainfall statistics using INSTAT v3.37 software analytical tools respectively. Observed agronomic and soil data were used to calibrate and validate the Crop model of the Decision Support for Agrotechnology Transfer (DSSAT) model. The model was used to simulate the impact of future climate changes and variability in bread wheat yield of Madda walabu and Sofumer varieties at Sinana district in Bale highlands. The results revealed that climate change caused variability in bread wheat productivity in the Sinana district within different time slices. There is a negative impact simulated at the Robe area except in the 2080s under RCP4.5 and 2050s and 2080s under RCP8.5 scenarios. Madda walabu yield is simulated to decrease up to -21.4% at Robe by 2050s under the RCP4.5 scenario relative to the baseline due to climate change impacts. For Sofumer, an increase in grain yield from the baseline condition was 7.0 % and 11.6 % by the near century (2030s) under both RCP4.5 and RCP8.5 scenarios respectively. Also, much yield reduction is experienced the 2050’s and 2080’s by 15.6 % and 27.0 % under RCP4.5. The decrease was expected by 21.9 % and 23.9 % in 2050 and 2080’s under RCP8.5 respectively. Therefore; climate change had a severe impact that justifies the need for a site-specific study. Therefore, future agricultural practices should benefit from agro-weather advisory services for farming decisions in the study of the area.