255-1 Nitrogen Fertilizer Recovery of Wheat Under Elevated Carbon Dioxide and Supplementary Irrigation In Southern Australia.



Tuesday, October 18, 2011: 1:05 PM
Henry Gonzalez Convention Center, Room 213B, Concourse Level

Shu Kee Lam, University of Melbourne, Horsham, VIC 3401, AUSTRALIA, Rob Norton, International Plant Nutrition Institute, Horsham, Australia, Roger Armstrong, Victoria Department of Primary Industries, Horsham, Australia and Deli Chen, University of Melbourne, Victoria, Australia
The effects of elevated [CO2] on growth, nitrogen (N) uptake and fertilizer-15N recovery by spring wheat (Triticum aestivum L. cv. Yitpi) were investigated under ambient (380 mmol mol–1) and elevated (550 mmol mol–1) [CO2] at the Australian Grains Free-Air Carbon dioxide Enrichment (AGFACE) experiment in southern Australia over a 2-year period. 15N-enriched (10.22 atom%) granular urea was applied to PVC microplots at 50 kg N ha–1 at rainfed and supplementary irrigated conditions for three experimental periods (2008 normal sowing (2008NS), 2008 late sowing (2008LS) and 2009 normal sowing (2009NS)). Elevated [CO2] increased the total biomass of wheat grown at 2008NS and rainfed plots of 2009NS by 27-58% and a concurrent total N uptake by 19-44%, while tissue N concentration remained unchanged. At these growth periods, the amount of plant N derived from soil increased by 20-50% under elevated [CO2], but that derived from fertilizer remained unchanged. At late sowing (warmer and drier), elevated [CO2] had no effect on wheat biomass, tissue N concentration and N uptake. In general, elevated [CO2] did not alter the percentage of fertilizer recovery in plant and in soil for any experimental periods. Supplementary irrigation increased grain yield by 94 and 37% for 2008LS and 2009NS, respectively. These results indicate that higher fertilizer application rate will be necessary in this wheat field under future [CO2] environments, whereas yield gains in future hotter and drier climates will be lower than in higher rainfall zones.

 

Keywords

Free-air carbon dioxide enrichment (FACE), supplementary irrigation, nitrogen uptake, nitrogen fertilizer recovery, wheat

See more from this Division: S04 Soil Fertility & Plant Nutrition
See more from this Session: Nutrient Losses