Simulating the Effect of Irrigation Water Salinity on Maize Yield under Climate Change Conditions in Ahvaz Region

In this research, the amount of maize yield was simulated under condition of different water salinities and climate change scenarios in Ahvaz region. Combined CSIRO-MK3.5 model and emission scenarios A1B, A2, and B1 were used as future (2021-2050 and 2070-2100) climate change scenarios (considering 1981-2010 as reference period). Additionally, AquaCrop model was used to predict the impact of climate change scenarios on maize yield under conditions of five salinity treatments including: (S0: Karoon river water (salinity: 2.3 dS/m); S1 (salinity: 3.5 dS/m), S2 (salinity: 4.5 dS/m); S3(salinity: 5.5 dS/m); and S4 (salinity: 6.5 dS /m). In order to show the impact of climate change alone, the amount of yield for each salinity treatment under different scenarios was compared with the same treatments yield under the reference scenario. Results showed that in the 2021-2050 period, the difference between maize yields for different scenarios was negligible compared to the reference scenario. However, in the 2070-2100 period, yield reduction under A1B scenario was %15, under B1 scenario 24%, and under A2 scenario, it was 35 percent. The results of salinity and climate change impacts together showed that, in the first future period, maximum reduction of yield would happen under the S4 B1N1 scenario (37 percent) and for the second future period, it would be under S4A2N2 scenario (58 percent). Finally, it was determined that the trend of yield reduction under salinity treatments was linear in all scenarios.