Inproceedings,
The effect of elevated carbon dioxide on the growth and yield of wheat in the Australian Grains Free Air Carbon dioxide Enrichment (AGFACE) experiment
Global Issues. Paddock Action, Proceedings of 14th Agronomy Conference 2008, (21-25 sep 2008)
Abstract
Current predictions indicate that Australia is likely to be particularly challenged by the impacts of rising atmospheric carbon dioxide and the consequent perturbations in climate. The Australian Grains Free Air Carbon dioxide Enrichment (AGFACE) project in Horsham, Victoria was designed to simulate predicted atmospheric carbon dioxide levels in the year 2050. The experiment measures the interacting effects of carbon dioxide (ambient aCO2 \~380 ppm, elevated eCO2 \~550 ppm), irrigation (rainfed, irrigated), higher temperatures during grain fill (time of sowing), nitrogen (0, +), and variety (Yitpi, Janz) on wheat growth and production. Carbon dioxide was injected over the crop in open-air 12 m rings from emergence (July) until maturity (December) in 2007. Crop development was not affected by eCO2. The effect of eCO2 was to increase crop biomass at maturity by 20\% (P<0.001) and anthesis root biomass increased by 49\% (P=0.004). Harvest index was not affected but mean grain yield across all treatments increased from 2.68 t/ha under aCO2 to 3.23 t/ha under eCO2. Both sowing time and additional water affected growth and yield but there were no significant interactions among these factors and eCO2. The effect of higher carbon dioxide was to slightly increase the number of kernels per spikelet (P=0.055). Water use, the sum of rainfall and change in soil water from sowing to maturity was 387 mm with no differences among the treatments other than irrigation. There were no significant interactions between carbon dioxide and genotype or nitrogen treatment on growth or yield. These data will be used to calibrate crop simulation models to assist with developing strategies to assist the grains industry adapt to the changing climate.
