Impacts of climate change on durum wheat (Triticum turgidum L var durum) production: analysis of future adaptation measures in the Central Rift Valley of Ethiopia

Assessing impact of climate change on durum wheat production and analysis of future adaptation measures bears enormous advantages in general and in Ethiopia in particular, owing to the country’s low adaptative capacity.The analysis shows that climate change will reduce durum wheat production in Central Rift Valley through time horizons i.e till the year 2030s, 2050s and 2080s.This study was conducted to characterize climate, assess its impact on durum wheat production and identify management options for the climate future dates in Ada'a district of the Central Rift Valley of Ethiopia. Daily climate data, normalized large scale Hadley Centre coupled Model version 3 model predictors and crop and soil data were analysed. Past and present climate variability characterization was assessed through seasonal rainfall amount, monthly rainfall statistics and dry spell length using R analytical tool and INSTAT climate guide. Temperature variability was examined in terms of pattern and trend. For future projection, Climate change scenarios for rainfall, minimum and maximum temperatures were developed for the period 2001-2099 by using the Hadley Centre coupled Model version 3 under A2a and B2a Special Report on Emission Scenarios using Statistical Downscaling Model version 4.1software. Decision Support System for Agro-technology Transfer, crop model was used to simulate future changes in durum wheat yield (Ude and Yerer cultivars) and to determine best adaptation measures in Ada'a area under modified environment. Seasonal rainfall amount was found to decrease with significance for 42 years period (P<0.05) while monthly rainfall statistics showed a high variation(CV of 80.6 to 34.4 % across months). Minimum and maximum temperatures showed an increasing trend at inter annual scale (0.21ºC per decade and 0.14ºC per decade respectively). The future projection analysis showed a decreasing trend of annual rainfall and increasing trend for temperatures during the period from 2001-2099. Accordingly, the average annual minimum temperature was found to rise in 2020, 2050 and 2080s for A2a and to decrease for B2a emission scenarios. While maximum temperature was predicted to increase in 2020, 2050s and 2080s under both emission scenarios. In 2080s, the average annual maximum temperature increment would be high for B2a scenarios. The crop model simulation indicated a positive impact on the cultivars in all time slice except in 2030 with Yerer. Furthermore, for Ude, yield will increase between 11.89 to 49.58 % across climate change scenarios relative to the baseline due to climate change by 2100s while for Yerer wheat yield will increase between 0.21 to 10.75 % across climate change scenarios relative to baseline due to climate change by 2100s. As adaptation options under changed climate conditions, Ude is the best than Yerer. And best agricultural practices have been found to be a combination of late planting date, high plant population and high fertilizer application rate. The cultivar has been found to be more sensitive on high fertilizer application rate. Therefore, growing Ude cultivar under future climate condition with improved management options such as high fertilizer application rate, improved soil water and planting in third dekad of July could ensure high yields during a good rainy season. Likewise, good yield could also be observed during a poor rainy season.