Prediction of climatic factors and water productivity of grain corn field (Zea mays L.) in the conditions of climate change

The study was conducted to simulate the effects of climate change on maize growth, production and water productivity. The evaluated factors included solar radiation, temperature, water consumption and evapotranspiration. The CERES-Maize model was used to simulate the evaluated characteristics. The results of GCM showed according to RCP4.5 and RCP8.5 scenarios, total radiation from 3418 under baseline conditions, will reach to 3983 and 3984 for near future period and 4006 and 4023 MJ/m2 for far future period, respectively. Under basal condition, average temperature was 22°C which based on RCP4.5 and RCP8.5, it will increase 2.3% and 4.3% in near future, and 8.5% and 17.2% in far future, respectively. Water consumed, water use efficiency and evapotranspiration in near climate change in RCP4.5 varied as 9.1, -5.4 and 7.7 -0.18 % and in RCP8.5 varied as, 9.2, -11.6 and 6.7% compared to baseline conditions, respectively. These values for RCP4.5 in far climate change were 9.7, -23.7 and 6.9% and for RCP8.5 were 10.1, -50.7 and 5.7%, respectively. Regarding to effect of sowing date, in climate change condition, by sowing the studied cultivars at late dates compared to the early dates and common date, water use efficiency was improved. Among the studied cultivars, Simon cultivar had the highest water use efficiency. In general, according to results, sowing of Simon cultivar in May 25 which had the highest water use efficiency, it can suggest as a suitable strategy to reduce the negative effects of climate change on maize production in Kermanshah region.