Modeling the effects of crop management on food barley production under a midcentury changing climate in northern Ethiopia

A crop simulation model was calibrated to (i) identify optimal planting date and quantify the impacts of nitrogen fertilizer and planting date on barley yield, and (ii) evaluate the responses of barley yield to climate change factors at Adigudom area, northern Ethiopia. Response of barley to seven planting dates at 10-days increments from 20-Jun and nine fertilizer rates at 16 kg/ha increments from 0 kg N/ha under five different soil types were evaluated. There were three irrigation treatment levels: I-0 (no irrigation application); I-1 (deficit irrigation: 4 irrigations); and I-2 (full irrigation). Response of barley to midcentury (2040-2069) climate data from three global climate models under higher emission scenario was evaluated. The model simulated the barley biomass, yield, days to flowering and maturity satisfactorily. The optimal planting window for coarse, medium and fine textured soils were July 1 to July 20, July 1 to July 30 and July 20 to August 10, respectively. The optimal N fertilizer for the respective soils was 64, 32 and 32 kg N/ ha, respectively. The difference between the simulated rainfed yield under optimal N fertilizer and on farm yield was estimated to be 1.1 Mg/ha. About 0.6 +/- 0.4 and 0.5 +/- 0.2 Mg/ha of the yield losses were due to nitrogen deficit and inappropriate planting date, respectively. Average barley grain yield is expected to decrease by 6-11% during the midcentury. This study showed that timely planting and N management along with elevated CO2 could contribute to yield enhancement and minimize the risk associated with future climate change.