Ferdowsi University of Mashhad Water and Soil 2008-4757 25 2 2011 06 22 Study on Climate Change Effect on Net Irrigation Requirement Study on Climate Change Effect on Net Irrigation Requirement 34553 10.22067/jsw.v0i0.9485 FA M. Soleymani Nanadegan Department of Irrigation and Drainage Engineering, College of Agriculture and Natural Resource, University of Tehran M. Parsinejad Department of Irrigation and Drainage Engineering, College of Agriculture and Natural Resource, University of Tehran 0000-0002-0653-8309 Sh. Araghinejad Department of Irrigation and Drainage Engineering, College of Agriculture and Natural Resource, University of Tehran A. Massah Bavani Department of Irrigation and Drainage Engineering, College of Aboureihan, University of Tehran Journal Article 2011 08 21 Abstract In this study, impact of climate change on net irrigation requirement (In) and yield of wheat using CGCM3 climate projection model, one of the AOGCM models, in Behshahr area is evaluated. changes in temperature and precipitation were simulated run under the IPCC scenario A2 for 2011-2040, 2041-2070 and 2071-2100 periods. This work was done by using statistical and proportional downscaling techniques. For In estimating, Potential evapotranspiration (ETo) and effective rainfall (Pe) were calculated using Hargreaves – Samani equation and USDA method, respectively. Impact of water deficit on crop yield was estimated using the linear crop-water production function developed by FAO. Results showed that Net irrigation requirement (In) will increase when sowing date is moved toward winter season which would be of further limitations under climate change conditions. For the specific proposed sowing dates, the relative crop yield reduction (YD) was not significantly changed in the future compared to base period. If the sowing date is moved forward to winter season, YD will increase due to a higher evapotraspiration and lower available effective rainfall. Keywords: Climate change, Net irrigation requirement, Wheat yield, General Circulation Model, CGCM3 Abstract In this study, impact of climate change on net irrigation requirement (In) and yield of wheat using CGCM3 climate projection model, one of the AOGCM models, in Behshahr area is evaluated. changes in temperature and precipitation were simulated run under the IPCC scenario A2 for 2011-2040, 2041-2070 and 2071-2100 periods. This work was done by using statistical and proportional downscaling techniques. For In estimating, Potential evapotranspiration (ETo) and effective rainfall (Pe) were calculated using Hargreaves – Samani equation and USDA method, respectively. Impact of water deficit on crop yield was estimated using the linear crop-water production function developed by FAO. Results showed that Net irrigation requirement (In) will increase when sowing date is moved toward winter season which would be of further limitations under climate change conditions. For the specific proposed sowing dates, the relative crop yield reduction (YD) was not significantly changed in the future compared to base period. If the sowing date is moved forward to winter season, YD will increase due to a higher evapotraspiration and lower available effective rainfall. Keywords: Climate change, Net irrigation requirement, Wheat yield, General Circulation Model, CGCM3 https://jsw.um.ac.ir/article_34553_8f279c77c332ff9a8c080e916cd21063.pdf