Effect of Future Climate Change on Wheat Yield and Water Use Efficiency Under Semi-arid Conditions as Predicted by APSIM-Wheat Model

Abstract

Any change in environmental conditions will affect crop growth and development and have an effect on crop productivity. The objective of the current study was to investigate the effect of climate change on irrigated wheat production and water use efficiency in Fars province in Iran. Accordingly, a general circulation model (HadCM3) was applied for two emission scenarios (A1B and A2) for three periods (2011–30, 2046–65 and 2080–2099) at nine locations in Fars province in central Iran. The APSIM (Agricultural Production Systems sIMulator) crop model was used to simulate growth and development of wheat as well as water use efficiency under future climate scenarios. The results indicated that the increase in CO2 concentration to 674 ppm in 2099 under A1B neutralized the negative effects of high temperature during the growing season and improved crop yield. The results indicate that, by the end of the century under the A2 emission scenario 10–15% of Fars province will have a grain yield of more than 10 t ha−1 and about 65% will have a grain yield of 8–10 t ha−1. Averaged across locations, scenarios and periods, water use efficiency increased by 3.56 kg ha−1 mm−1 in the future scenarios over baseline. Overall, the improved water use efficiency under future climate change was largely the result of a significant increase in yield (from 6989.5 kg ha−1 at baseline to 8416.5 kg ha−1 in all future scenarios) and decreased evapotranspiration (from 506.8 mm at baseline to 478 mm in all future scenarios).