Modelling the Impacts of Climate Change on Irrigated Wheat Yield Under Water Limited Conditions in Khorasan Razavi Province

The current study was conducted in six locations of Khorasan Razavi province (Ghoochan, Gonabad, Mashhad, Sabzevar, TorbateHeydariyeh and TorbateJam). At first, future climate (2050) was generated using long term climate data of baseline (2010-1980) and by AgMIP method on two climates scenario (RCP4.5, RCP8.5). A Global Circulation Model namely MPI-ESM-MR along with APSIM-Wheat model were used for growth and yield simulation of wheat under water-limited conditions. Simulating results showed that average changes in growth season temperature will be increased as 14.4 and 18.6 percent in the studied areas in future in comparison with baseline for RCP4.5 and RCP8.5, respectively (1.41 and 1.83 °C compared with the baseline). Also, results indicated that the length of growing season and days to flowering will be declined 13 to 24.6 days and 13.2 to 30.4 days, respectively. In this research, the grain yield had positive changes in future in most of the studied locations due to the interaction of temperature and CO2. The results of this study also revealed that changing sowing date could result in an increase in grain yield in future. Locations with higher baseline temperature well responded to two weeks earlier in sowing date while locations with lower baseline temperature had good performance in sowing date of two weeks later which resulted in further yield increase in the future. Overall, the findings of this study suggested that changing sowing date in future could further increase wheat grain yield which is highly important for food security, according to the increasing demand in future.