Impacts of increasing CO2 and temperature due to climate change on wheat yield in Khuzestan province: A simulation study

The current study was implemented by using general circulation models (GCMs) aiming at predicting the future climate change as well as its impacts on wheat yield in seven locations of Khuzestan province including Ahwaz, Dezful, Ezeh, Behbahan, Bandar Mahshahr, Ramhormoz and Omidiye. Accordingly, general circulation model of HadCM3 (United Kingdom Met Office Hadley) under three emission scenarios (B1, A1B and A2) for three time periods (2011-30, 2046-65, 2080-2099) were investigated. LARS-WG software was used to generate daily climate parameters. The outputs of LARS-WG were used as inputs for APSIM crop simulation model to simulate growth and development of wheat under future climate change. According to the results obtained, the future minimum and maximum temperatures in Khuzestan will have increasing trend. Simulation results also showed that grain yield, biomass yield and leaf area index (LAI) substantially increased in all locations under future climate compared with the baseline period. Compared to the baseline, the highest wheat grain yield in the future would be obtained in Izeh and Ramhormoz (7691 and 6596 kg ha-1, respectively). Overall, it is concluded that over the coming decades, the wheat grain yield in Khuzestan province will have increasing trend largely due to an increase in LAI (which is highly correlated with grain yield). Other growth characteristics such as length of growing season had less impact on grain yield compared with the LAI under climate change in all study locations. Also, locations with cooler temperature in the baseline (i.e. Izeh) will produce higher grain yield in the future.