University of Tehran perss Journal of Crops Improvement 2008-8337 24 4 2022 12 22 The Effect of Climate Change on Yield Potential and Water Productivity of Forage Maize in Iran The Effect of Climate Change on Yield Potential and Water Productivity of Forage Maize in Iran 1247 1263 86955 10.22059/jci.2022.334981.2648 FA Hosna Fayazi Department of Agronomy, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. E-mail: h.fayaz222@gmail.com Ebrahim Zeinali Corresponding Author, Department of Agronomy, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. E-mail: e.zeinali@gau.ac.ir Afshin Soltani Department of Agronomy, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. E-mail: Afshin.Soltani@gau.ac.ir Benyamin Torabi Department of Agronomy, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. E-mail: b.torabi@gau.ac.ir 0000-0002-9788-3828 Journal Article 2021 12 03 Global climate change is among the most important agricultural and food security challenges. This study tries to investigate the effect of climate change on potential yield and water productivity of forage maize (<em>Zea mays</em> L.) in Iran. Two scenarios of RCP4.5 and RCP8.5 are used to predict the future climate (2050s) and climate data of 2001-2015 have been used as the base period. Potential yield is estimated using SSM-iCrop2 model according to the GYGA protocol and the climate changes for both scenarios are applied in the model. The results show that the climate change will not have a considerable effect on forage maize yield compared to the current conditions (85.6 ton ha^-1) and will only lead to an increase of 0.9% and 1.6% in on both scenarios, respectively. This may be attributed to maize being a C4 plant and thus non-effectiveness of CO₂ increase on its growth. Also, the temperature will remain in optimum range for maize in most of the main regions for forage maize cultivation areas in Iran. Water productivity in both scenarios will increase by 0.4% and 1.6%, compared to current conditions (10.4 kg m^-3), respectively, which may be due to increased CO₂ concentration and more closure of stomata. Also, improved water productivity in forage maize may be attributed to increase yield potential due to the fact that no considerable changes are observed in terms of the required water, evapotranspiration and irrigation times.   Global climate change is among the most important agricultural and food security challenges. This study tries to investigate the effect of climate change on potential yield and water productivity of forage maize (<em>Zea mays</em> L.) in Iran. Two scenarios of RCP4.5 and RCP8.5 are used to predict the future climate (2050s) and climate data of 2001-2015 have been used as the base period. Potential yield is estimated using SSM-iCrop2 model according to the GYGA protocol and the climate changes for both scenarios are applied in the model. The results show that the climate change will not have a considerable effect on forage maize yield compared to the current conditions (85.6 ton ha^-1) and will only lead to an increase of 0.9% and 1.6% in on both scenarios, respectively. This may be attributed to maize being a C4 plant and thus non-effectiveness of CO₂ increase on its growth. Also, the temperature will remain in optimum range for maize in most of the main regions for forage maize cultivation areas in Iran. Water productivity in both scenarios will increase by 0.4% and 1.6%, compared to current conditions (10.4 kg m^-3), respectively, which may be due to increased CO₂ concentration and more closure of stomata. Also, improved water productivity in forage maize may be attributed to increase yield potential due to the fact that no considerable changes are observed in terms of the required water, evapotranspiration and irrigation times.   https://jci.ut.ac.ir/article_86955_db9e4d2ef601dae334d26b11611b6fe2.pdf