FACEing South: The Australian Grains Free Air CO2 Enrichment (AGFACE) Experiment - Effects of Elevated CO2 On Wheat Production.

The Australian Grains Free Air CO₂ Enrichment (AGFACE) experiment in Victoria, Australia creates elevated atmospheric [CO₂] (eCO₂) levels expected to occur in 2050 to study wheat production under a range of environments. One main objective was to generate data to improve and validate crop models under relatively low water inputs (230-460 mm). This will help inform industry to develop adaptation policies for climate change. Between 2007-2009 there were 3 physical facilities: (1) the core site at Horsham where measurements were collected on the impacts of irrigation (2 levels), different temperatures at heading (2 times of sowing), nitrogen inputs (2 levels) and cultivar (2-8 varieties) on wheat production under ambient (380 ppm) and eCO2 (550 ppm) levels; (2) Walpeup, where CO₂ by time of sowing was investigated in a warmer, drier climate, and (3) in a SoilFACE experiment at Horsham where a CO₂ (2 levels) by soil type (3 types) by rotation (wheat and field pea) experiment commenced in 2009. Results indicate increased biomass and yield of 17% to 50% due to eCO₂, depending on year, location and treatment. Grain and leaf N concentrations were both reduced but total N uptake increased. Pests and diseases responded differentially to eCO₂, with crown rot (Fusarium pseudograminerarum) showing increased fungal biomass. In 2009, 8 varieties of wheat were sown that incorporated a range of traits expected to respond to eCO₂ including sink strength, transpiration efficiency and early vigor. Results indicate that medium tillering types had greater yield response to eCO₂. Early simulation modelling results scaled to the landscape show that drier regions will experience decreased yield, despite the CO₂ “fertilization” effect. Beginning in 2010, the AGFACE Horsham site will include a range of field pea and wheat varieties in annual rotation to study the interacting effects of the treatments on the agronomy and physiology of this system. The overall FACE program will be described.