University of Tehran Press Iranian Journal of Soil and Water Research 2008-479X 52 10 2021 12 22 Investigation the Effect of Climate Change and Planting Date on Maize Yield using WOFOST Model Investigation the Effect of Climate Change and Planting Date on Maize Yield using WOFOST Model 2515 2527 85533 10.22059/ijswr.2021.327604.669034 FA Pezhman Salarieh MSc Student of Irrigation and Drainage, Sari Agricultural Sciences and Natural Resources University Mojtaba Khoshravesh 1- Department of Water Engineering, Faculty of Agricultural Engineering, Sari Agricultural Sciences and Natural Resources University, Sari, Iran. 0000-0001-8635-3322 Reza Norooz Valashedi Assistant Professor, Water Engineering Department, Sari Agricultural Sciences and Natural Resources University, Sari, Iran. 0000-0003-1543-0866 Alireza Kiani Agricultural Engineering Department, Golestan Agricultural and Natural Resources Research and Education Center, Gorgan, Iran 0000-0002-2345-5089 Journal Article 2021 07 22 Given the advancement of technology and the growing population in the world, the need to recognize and pay attention to the phenomenon of climate change is inevitable. The purpose of this study is to investigate the changes in maize yield for future years in Gorgan with a change in planting date. In this research, the grain yield of maize SC late maturing for future conditions was investigated using WOFOST model in Gorgan city based on different deficit irrigation treatments and different planting dates. Irrigation treatments including 100% (T1), 75% (T2) and 50% (T3) of water requirement. For this purpose, using SDSM statistical model and HadCM3 general circulation model for all scenarios, the fifth microscale report was performed in the next two thirty-year periods (2020-2050 and 2050-2080). Data for the period 1980-1995 were used to calibrate the SDSM model and data for the period 1995-2010 were used for validation. The WOFOST model was calibrated by the measurement data of 1391 and then the data of 1392 were used for validation. Statistical indices of root mean square error (RMSE), compatibility index (d), model efficiency coefficient (E), explanation coefficient (R²) and residual coefficient (CRM) related to grain yield simulation in calibration period was equal to 0.217 tons per hectare, 0.97, 0.94, 0.93 and 0.15, respectively and in the validation period, was obtained 0.241 tons per hectare, 0.98, 0.93, 0.96 and 0.14, respectively. The numbers obtained indicate the good performance of the WOFOST model. Also, the maize grain yield was simulated for four different planting dates in three treatments of T1, T2 and T3. In the period 2020-2050, the lowest yield was predicted 4.3 tons per hectare in T3 treatment under the RCP8.5 scenario on 2 June, which is a decrease of 32.81% compared to the base period. In the period 2050-2080, the lowest yield was predicted 3.3 tons per hectare in T3 treatment under the RCP8.5 scenario on 2 June, which is a decrease of 48.43% compared to the base period. The best planting date for corn in Gorgan city is June 23, which can be used for better management of cultivation and irrigation in Gorgan. Given the advancement of technology and the growing population in the world, the need to recognize and pay attention to the phenomenon of climate change is inevitable. The purpose of this study is to investigate the changes in maize yield for future years in Gorgan with a change in planting date. In this research, the grain yield of maize SC late maturing for future conditions was investigated using WOFOST model in Gorgan city based on different deficit irrigation treatments and different planting dates. Irrigation treatments including 100% (T1), 75% (T2) and 50% (T3) of water requirement. For this purpose, using SDSM statistical model and HadCM3 general circulation model for all scenarios, the fifth microscale report was performed in the next two thirty-year periods (2020-2050 and 2050-2080). Data for the period 1980-1995 were used to calibrate the SDSM model and data for the period 1995-2010 were used for validation. The WOFOST model was calibrated by the measurement data of 1391 and then the data of 1392 were used for validation. Statistical indices of root mean square error (RMSE), compatibility index (d), model efficiency coefficient (E), explanation coefficient (R²) and residual coefficient (CRM) related to grain yield simulation in calibration period was equal to 0.217 tons per hectare, 0.97, 0.94, 0.93 and 0.15, respectively and in the validation period, was obtained 0.241 tons per hectare, 0.98, 0.93, 0.96 and 0.14, respectively. The numbers obtained indicate the good performance of the WOFOST model. Also, the maize grain yield was simulated for four different planting dates in three treatments of T1, T2 and T3. In the period 2020-2050, the lowest yield was predicted 4.3 tons per hectare in T3 treatment under the RCP8.5 scenario on 2 June, which is a decrease of 32.81% compared to the base period. In the period 2050-2080, the lowest yield was predicted 3.3 tons per hectare in T3 treatment under the RCP8.5 scenario on 2 June, which is a decrease of 48.43% compared to the base period. The best planting date for corn in Gorgan city is June 23, which can be used for better management of cultivation and irrigation in Gorgan. https://ijswr.ut.ac.ir/article_85533_28982e4cf11285dad8a8ce2be1467606.pdf