CLIMATE CHANGE IMPACTS AND ADAPTATION FOR CROP MANAGEMENT OF WINTER WHEAT AND MAIZE IN THE SEMI-ARID REGION OF IRAN

Climate change is expected to lead to declining crop yields in semi-arid regions due to higher temperatures and more severe droughts, which calls for adaptations in crop management. We used the WOFOST and AquaCrop crop simulation models to examine the response of crop yield in winter wheat and maize to a set of climate change scenarios up to 2040 in the semi-arid climate of Mashhad in north-east Iran. Modelled climate change from six AOGCMs including GFCM21, HADCM3, INCM3, IPCM4, MPEH5 and NCCCSM under IPCC SRES A2 and B1 emission scenarios was used. The crop models were calibrated and validated against 7 years of observed crop yield data, confirming that the models adequately simulated yields of wheat and maize in the study area. The bootstrap method was used to estimate the uncertainty of crop yield projections. The results showed a mean yield decrease of 10-34% for winter wheat and 8-18% for maize, depending on the crop model and climate change scenario. The period of flowering to maturity of winter wheat and maize would be shortened on average by 9 and 5 days, respectively. Changes in crop management were considered for adaptation to climate change. Simulation results indicated that early sowing of winter wheat and late sowing of maize enhanced yield and water productivity across all climate change scenarios and that late-maturity cultivars of winter wheat and early-maturity hybrids of maize generally have higher productivity than standard cultivars. Increasing heat tolerance of the crops and changing irrigation management of winter wheat were also found to be beneficial adaptation options. (c) 2019 John Wiley & Sons, Ltd.