Fitzgerald, G.J., Tausz, M., O'Leary, G., Mollah, M.R., Tausz-Posch, S., Seneweera, S., Mock, I., Low, M., Partington, D.L., McNeil, D. and Norton, R.M. 2016. Elevated atmospheric [CO2] can dramatically increase wheat yields in semi-arid environments and buffer against heat waves. Global Change Biology 22: 2269-2284.
Working at the Australian Grains Free Air CO2 Enrichment facility, Fitzgerald et al. (2016) compared wheat (Triticum aestivum) growth and yield under ambient (aCO2 370 ppm) and elevated (eCO2 550 ppm) atmospheric CO2 concentrations at two dryland sites (Horsham and Walpeup) over a three-year period of working with two cultivars, two sowing times and two irrigation treatments. And what did they learn by so doing?
The eleven Australian researchers report that (1-3) "mean yield stimulation due to eCO2 was 24% at Horsham and 53% at Walpeup, with some treatment responses greater than 70%," that (4) "under supplemental irrigation, eCO2 stimulated yields at Horsham by 37% compared to 13% under rain-fed conditions," and that (5) "heat wave effects were ameliorated under eCO2 as shown by  reductions of 31% and 54% in screenings [percent of grain less than 2 mm] and  10% and 12% larger kernels (Horsham and Walpeup)."
Last of all, in terms of the bigger picture, Fitzgerald et al. report that "the large responses to eCO2 under dryland conditions have not been previously reported and underscore the need for field level research to provide mechanistic understanding for adapting crops to a changing climate."Posted 16 November 2016