NSW Department of Primary Industries, Wagga Wagga NSW, Australia.
Canola is one of the major crops planted across Australia’s wheatbelt. Water shortages and uneven distribution of water resources are the key limitations for Australia canola productivity. This is expected to be aggravated in the warmer and dryer future climates with higher rainfall variability, leading to a threat to Australia canola industry. However, the increase of atmospheric CO2 concentration has the potential to increase crop yield and water use efficiency (WUE). Therefore, there is a need to conduct a comprehensive assessment by combining the impacts of the changes in future climate and atmospheric CO2 concentrations on canola yield and WUE for providing a fundamental insight for future Australia canola industry. In this study, we tested APSIM-Canola module against the experimental data, collected in 2013-2014 and 2016 in Wagga Wagga. The tested model was then used to predict canola yield and WUE in both historical and future climatic conditions. The simulation results showed ASPIM-Canola module captured the variations of canola yield across fertilizer applications and climatic variations. Comparisons between historical and projected future climates, there is an overall tendency for a decline of cumulative rainfall in canola growing seasons and an increase of air temperature. As a consequence, the increasing temperature and decreasing rainfall leads to a clear decline of canola yield and WUE, however, this negative impact could be offset by the positive impact of increasing atmospheric CO2 concentration on canola yield and WUE. This scenario analysis provides a foundation towards understanding changes in Australia’s canola cropping systems.