Abstract

Modeling the Impacts of Climate Change on Chickpea Production in Adaa Woreda (East Showa Zone) In the Semi-Arid Central Rift Valley of Ethiopia

Mengesha Lemma Urgaya

Since agriculture is highly dependent on Mother Nature such as soil, water and climatic conditions, the extreme weather events and climatic conditions have major impacts on agriculture. Likewise, climate change has become one of important up growing issues and the biggest concern of mankind as a consequence of scientific evidence about the increasing concentration of greenhouse gases (GHG) in the atmosphere. Therefore, simulating future climate on chickpea production is very essential for the study area. The Future climate was simulated based on one Global Climate Model (HadGEM2-ES) with three time period and two representative concentration pathways (RCP s). Moreover, DSSAT V4.6 model was calibrated, evaluated and used for simulating yield of chickpea under baseline and future climate. To do that the model was calibrated and evaluated using experimental phonological and yield data obtained from Debrezeit Agricultural Research Center (DARC). The result show that the projected rainfall showed a decreasing trend over the 2020s by -1.5% and 2050s by -4.5% under RCP 4.5 whereas it showed an increasing trend over the 2080s by 12.1% when simulated under RCP 8.5. While the maximum and minimum temperature in Adaa woreda projected to rise under RCP 4.5 and RCP 8.5 scenarios in different rate. The temperature trend generally showed greater warming in the coming 2010 to 2099 in both emission scenarios. The days to flowering, maturity and yield of Arerti variety simulated by the model was calibrated and evaluated by Root Mean Square Error (RMSE), Index of agreement (IA) and coefficient of determination (R2). Therefore, RMSE, IA and R2 were revealed a very nice agreement with observed data’s set. These indicates good relationships of the observed with simulated values of the model. Similar to the model calibration, the performance of the model evaluation indicates a very good agreement with the observed data. Then, it was convincing enough to undertake climate change impact analysis using this model (DSSAT - CROPGRO). The result showed that planting time could be used as climate change adaptation strategy in the study area. Accordingly early planting (on July 20) was found to have significant increase of chickpea yield when compared to normal (August 20) and late (September 10) planting in the study area. To adapt to the changing climate, early planting, moisture conservation during less availability of water and drainage during water logging and climate adviser service would be better option.