CR 72:83-99 (2017)  -  DOI:

Spatiotemporal changes in wheat phenology, yield and water use efficiency under the CMIP5 multimodel ensemble projections in eastern Australia

Bin Wang1,2,*, De Li Liu2, Senthold Asseng3, Ian Macadam4,6, Xihua Yang5, Qiang Yu

1School of Life Sciences, Faculty of Science, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia
2NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Wagga Wagga, NSW 2650, Australia
3Agricultural & Biological Engineering Department, University of Florida, 221 Frazier Rogers Hall, PO Box 110570, Gainesville, FL 32611-0570, USA
4Climate Change Research Centre and ARC Centre of Excellence for Climate System Science, University of New South Wales, Sydney, NSW 2052, Australia
5New South Wales Office of Environment and Heritage, Parramatta, NSW 2150, Australia
6Present address: Met Office, FitzRoy Road, Exeter EX1 3PB, UK
*Corresponding author:

ABSTRACT: The New South Wales (NSW) wheat belt is one of the most important regions for winter crops in Australia; however, its agricultural system is significantly affected by water stress and ongoing climate change. Statistically downscaled scenarios from 13 selected global climate models with RCP4.5 and RCP8.5 scenarios were combined with crop simulation models to simulate wheat productivity and water use. We projected that multi-model median yields could increase by 0.2% for RCP4.5 and 9.0% for RCP8.5 by 2061-2100. Although RCP4.5 showed a small decrease in median yield in the dry southwestern parts of the wheat belt, the higher CO2 concentration in RCP8.5 compensated some of the negative effects, resulting in 12.6% yield increase. Our results show that drier areas would benefit more from elevated CO2 than would the wetter areas. Without the increase in CO2 concentration, wheat yields decrease rapidly under RCP4.5 by 2061-2100 and much more so under RCP8.5 compared to the present. A decline in growing season length and a decrease in rainfall resulted in reduced crop water consumption. As a consequence, simulated evapotranspiration decreased by 10.2% for RCP4.5 and 16.9% for RCP8.5 across the NSW wheat belt. Increasing yields combined with decreasing evapotranspiration resulted in a simulated increase in water use efficiency by 9.9% for RCP4.5 and 29.7% for RCP8.5. Wheat production in water-limited, low-yielding environments appears to be less negatively impacted or in some cases even positively affected under future climate and CO2 changes, compared to other growing environments in the world.

KEY WORDS: Global climate model · Wheat yield · Water use efficiency · Evapotranspiration · Agricultural Production System Simulator · APSIM

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Cite this article as: Wang B, Liu DL, Asseng S, Macadam I, Yang X, Yu Q (2017) Spatiotemporal changes in wheat phenology, yield and water use efficiency under the CMIP5 multimodel ensemble projections in eastern Australia. Clim Res 72:83-99.

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