Abstract:
Studying climate change and variability at a local scale is curial for devising proper
strategies that enhance adaptive capacity. In view of this, this study was conducted in
Welmera District, to assess; the impacts of climate change on faba bean (Vicia faba
L.) production. Historical climate and crop yield data were obtained from National
Meteorological Agency of Ethiopia and Holeta Agricultural Research Center respectively.
After quality control, consistency check and homogeneity test on rainfall and temperature
data; trend, variability, correlation and regression analysis were carried out by statistical
software InStat_v3.36, XLSTAT2014 and SPSS_v20 were used. Future climate data was
downscaled by average ensemble of four GCMs climate models (BSS-CSM1-1, HadGEM2-ES,
MIROC-ESM and NorESM1-M) under RCP4.5 and RCP8.5. The time period centered 2030s
and 2050s were considered. The results indicated that the average of main rainy season
(JJAS) for Holeta station started on the 3rd decade of May. The annual, kiremt, belg and bega
seasonal rainfall amount were found to be decreased by a factor of 8.53, 4.7, 2.32 and 0.8
mm/year, respectively. The mean maximum and minimum temperature revealed an increasing
trend by 0.005 and 0.06 0C changes/year. Moreover, the correlation of kiremt start of rain and
kiremt rainy day had negative impact on Gora yield with (r=-0.407 and -0.369) respectively.
Similarly, kiremt start of rainy season and mean air temperature had negative impacts (r=-
0.482 and r=-0.605) where moderate and strong correlated with Tumsa yields and
statistically significant at p-value levels (0.01 and 0.05) in the study area. The coefficient of
determination was analyzed with (R2 =56.0% and 74.4%) of total variance in Gora and Tumsa
yields respectively were explained jointly by climatic events. The future projection of highest
mean monthly rainfall and air temperature changes occur during faba bean growing season
will in July (147.3%) mm/months and August (0.24 0C/month) under RCP8.5. However, in
August and September mean monthly rainfall will be dramatically decrease by 50.85 % and
31.05% mm/month in the 2020 up to 2079 under RCP 8.5 and RCP 4.5 respectively. Tumsa
yield will significantly decline by 24.19% under RCP8.5 mid-century. If future study consider
using different climate and crop models with more appropriate adaptation management
options incorporate is better for further study
