Modelling the impacts of climate change on faba bean (Vicia faba L.) production in Welmera area, central Ethiopia

Climate change is affecting agricultural production and other aspects of life but only limited number of studies took interest in characterizing and projecting climate and its impact on crop production at local level. The threat to agricultural sector is more serious in Ethiopia, where climate is influenced by diverse topography and varying landscape features. This study was conducted in Welmera area to model the impacts of climate change on production of two faba bean (Vicia faba L.) varieties (Tums and Gora). Historical climate and crop yield data were obtained from the National Meteorological Agency of Ethiopia and Holeta Agricultural Research Center, respectively. Future climate data were downscaled by an average ensemble of four GCMs (BSS-CSM1-1, HadGEM2-ES, MIROC-ESM, NorESM1-M) in near- and mid-century (2030s and 2050s) under both RCP 4.5 and RCP 8.5. Rainfall by near-century will increase by up to 50% depending on the concentration pathway considered compared to the baseline period (1988–2017). The projected average rainfall total of belg season (FMAM) will increase by 88.17% under RCP 4.5 scenario and 95.38% under RCP 8.5 scenario in near-century. The future projection revealed that the highest mean monthly rainfall and temperature changes will occur in July (147.3 mm/month) and August (0.24 °C/month) under RCP8.5. However, in August and September mean monthly rainfall will decrease dramatically by 50.85 % and 31.05% from 2020 to 2079 under RCP 8.5 and RCP 4.5, respectively. The yield of Tumsa variety will decrease by up to 24.19% under RCP8.5 in mid-century. Gora variety will see an increase of yield by 18.24% under RCP 4.5 in mid-century and 28.03% under RCP 8.5 in near-century. Overall, the area will experience an increase and a decrease in faba bean yield for both varieties in the upcoming decades in the study area. Performance evaluation of the models showed that they were able to predict future yield faba bean varieties in the area with acceptable accuracy. Inconsistency of future climate variables and impact on fababean production underscores the need to develop location-specific adaptation strategies. Further studies that consider wider area could be necessary to better understand the impact of future climate on faba bean production in the study area and similar agroecologies in the country.