ASSESSING IMPACT OF CLIMATE CHANGE ON SORGHUM (Sorghum bicolor L.) AND WHEAT (Triticum aestivum L.) PRODUCTION IN NORTHERN ETHIOPIA

Agriculture is the most vulnerable sector to the impacts of climate change and climate variability and needs high demand for quantitative information on the impacts. In this case, a crop model, Decision Support System for Agro-technology Transfer, and global climate models were used to assess climate impacts on sorghum and wheat yields and to explore specific adaptation options for mid (2040-2069) and end (2070-2099) centuries under medium (RCP4.5) and highest (RCP8.5) emission scenarios in northern Ethiopia. The crop simulation model was calibrated and validated using crop experimental, soil and historical climate data sets from Enderta and Kobo sites. With this, the simulation experiment was carried out for early maturing sorghum cultivars (Teshale and Melkam) and Mekele-1 wheat cultivar using historical climate data of Sirinka (1985-2014), Kobo (1985-2014) and Enderta. (1981-2010) and future climate change scenario data downscaled from general circulation models. The simulation result revealed that sorghum yield is expected to decrease by 1.2-23% conditional to emission scenarios, period of analysis, variety and the study location considered. Whereas, wheat yield is expected to increase by 2.2-6.6% depending on the emission scenarios considered by 2050s while yield is predicted to decline by 2.3% at the end of the century under the highest emission scenarios. Result of thesensetivity analysis indicated that Teshale variety is highly sensitive to environmental change from the baseline climate at Kobo and Sirinka. On the other hand, regardless of rainfall variation, a rise in temperature up to 3 oC would result in an increase in yield by 2.3-13.8% for melkam variety. However, the rise of atmospheric CO2 by 540 and 750 ppm from the current level would result in an increase of yield from 4.5 to 6.9% for sorghum and up to 25.7% for wheat. However, adaptation practices such as, increasing fertilization and increasing plant population would offset the adverse impacts of climate change on sorghum and wheat production. Mid-June planting for sorghum production at Sirinka and Kobo gives better yield than normal and late planning; while mid-June and mid-July planting would intensify the negative impactsof climate change at Enderta. All in all, change in planting date at Enderta would not reward wheat production under the changing climate