Climate change impacts modeling on winter wheat yield under full and deficit irrigation in Myandoab-Iran

In this research, impact of climate change on wheat yield was simulated using SWAP in Myandoab, Iran. Field data of wheat in 2004-2005 and 2005-2006 periods were used for calibration and validation of the SWAP, respectively. The HadCM3 outputs, for A1B, A2 and B1 scenarios and 2046-2065 periods, were used in SWAP and wheat yield in mentioned period was compared with base period. Three irrigation levels, based on meeting 100, 70 and 50% of the crop ET demand, were used to study the climate change effects on wheat yield in full and deficit irrigation conditions. The results showed that temperature and reference evapotranspiration will increase in 2055s. Temperature increase cause to decrease crop growing period and crop evapotranspiration. The results showed that the negative impact of temperature increase has dominated to the positive impact of CO2 concentration and the yield is reduced. For full irrigation situation, the reduction will be 24.1, 22.4 and 20.8% in A1B, A2 and B1, respectively. Reduction in yield can be related to the shorter maturity period of the crop. The results showed that under deficit irrigation, the yield is also decreased but this decrease rate of yield is higher in full irrigation.