Performance of agro-climate indices and wheat grain yield in a changing climate

© 2016 Inter-Research. This study aimed to assess the performance of 8 agro-climate indices and wheat yield in 2030 and 2050 at 3 locations (Moree, Dubbo and Wagga Wagga) on a north-south climatic gradient in eastern New South Wales, Australia, by coupling downscaled outputs of 4 climate models with a mechanistic wheat model. These locations represent the transition of grain production systems from those with summer-dominant to those with winter-dominant rainfall. Simulation showed (1) ambiguous results in the frequency changes of frost occurrence across locations, phenophases, study period and sowing times; (2) a substantial increase in the frequency of heat stress during the flowering period across sowing times, study periods and locations; (3) a decrease in pre-and postflowering rainfall in most cases; (4) no change in soil water deficit (SWD) in 2030 in 31 out of 42 cases (the combination of 7 sowings, 2 phenophases and 3 locations) and a decrease (by 0.2) or no change in SWD in 2050 in 18 out of 42 cases; and (5) a decrease, increase, or absence of change in wheat yield depending on locations, with sowing times in 2030 increasing more or decreasing less. Changes in wheat grain yield reflected the changing patterns of agro-climate indices. The concurrent occurrence of heat stress and terminal drought at wheat reproductive stages will pose significant challenges for sustainable development of the wheat industry in the future