BARLEY YIELD ESTIMATION IN RESPONSE TO PROJECTED CLIMATE CHANGE IN BASONA WERANA DISTRICT NORTH SHEWA ZONE OF AMHARA REGION, ETHIOPIA

Abstract

This study examines the impact of future climate change on barley yields in the Basona Werana District using the Decision Support System for Agrotechnology Transfer (DSSAT) model, complemented by an analysis of climate extremes through ETCCDI indices. The research leverages historical weather data from the Ethiopian Meteorological Institute and future climate projections under two Shared Socio-economic Pathways (SSPs) scenarios (SSP245 and SSP585) from the Coupled Model Intercomparison Project Phase 6 (CMIP6) models. The study employs Mann-Kendall test and Sen's slope estimator for annual trend analyses to assess changes in climate extremes. Expert Team on Climate Change Detection and Indices (ETCCDI) indicate significant trends in temperature extremes, with increases in indices such as frequency of warm nights (TN90p), Warm Days (TX90p), hottest night (TNx), and warmest day (TXx), while indices like frequency of cool days (TX10p) and cold nights (TN10p) show decreasing trends. Precipitation extremes present mixed trends with few significant changes. The DSSAT model, calibrated with experimental data from two barley cultivars, demonstrated strong performance with a root mean squared error (RMSE) of 0.162 t/ha, R² of 0.99, and d-index of 0.95 for calibration, and RMSE of 0.593 t/ha, R² of 0.833, and d-index of 0.887 for validation. Projected barley yields under SSP585 are expected to decline by 12.95% to 32.31% in the mid-century and by 17.39% to 43.14% by the end-century. Even under the medium-emission SSP245 scenario, declines are projected to be 9.78% to 29.39% in the mid-century and 13.12% to 40.08% by the end-century. These results underscore the urgent need for adaptive measures in farming practices to mitigate the adverse effects of climate change and ensure the long-term viability of barley production in the Basona Werana District.