Abstract

Even though, there is a general understanding on the impact of climate change and variability on agricultural crops,the spatial and temporal variability of these impacts remains yet uncertain. Thus, modeling the likely impact of climate change on cereal crops at local level is crucial for developing possible future options of adaptation and mitigation strategies. This research was conducted with the objective of modeling the impact of climate change and variability on sorghum production. Hence, calibration and evaluation of agricultural production system simulator (APSIM) model was conducted using four years research data (2006 to 2009) and its performance was assessed using coefficient of determination (r2), root mean square error (RMSE) and index of agreement (d). According to the HadGEM2-ES model, an increase of maximum (5.9°C) and minimum (6.4°C) temperature was revealed in the end term (2080s) over the base year. Similarly precipitation was predicted to increase by 27% in the end term while almost constant for the other periods. The monthly accumulated heat unit was increased in all periods and this has shortened the maturity date of sorghum by about a week compared to the historical. Keeping the current sowing window (April) and other management activities the same, future Sorghum yield has simulated to decrease between 5% and 24%. Using both the historical and predicted climate data, sowing on March followed by April has shown a reasonable yield advantage in both RCPs. The response of the different sorghum cultivars to the future climate changes should further be studied for deciding which cultivar could give a better yield for the future under different management options.

Keywords: GDD; APSIM; HadGEM2-ES; Climate; Modeling