Americas and Oceania Group - International Plant Nutrition Institute

Americas and Oceania Group
Australia/New Zealand Region: Dr. Robert Norton
Oceania
Wheat Grain Nutrient Content for Southeastern Australia
Project Leader: Rob Norton, IPNI, Horsham, Victoria. E-mail: rnorton@ipni.net.
Project Cooperators: Alan Bedggood (ACAS Ltd), Robert Wheeler (South Australian Research and Development
Institute), Frank Mcrae (Industry and Investment, New South Wales), Angela Clough (Victorian Department of
Primary Industries), and Harpreet Gill (Agrisearch Services Pty Ltd.).
Grain nutrient concentrations for macronutrients and micronutrients were analyzed from more than 70 NVT
(National Variety Trials) sites across southeastern Australia. All nutrients tested showed significant differences
among regions. Values for the macronutrient P were the most variable (3,329 ± 661 mg/kg) and was more
than the commonly used value of 2,900 mg/kg. The variation in grain P content could not be related to soil
P test, fertilizer application or grain yield although values varied among regions and states. Sulphur and K
levels also showed significant differences among regions, while grain zinc (Zn) levels seemed lowest in
regions characterized by alkaline soils.
These data suggest that regional or even paddock-based nutrient concentrations may be required when
constructing nutrient balances. It may also be useful to use grain micronutrient content as a monitoring
tool to indicate the need for fertilizer additions. These results will be published at the Australian Society of
Agronomy annual meeting in October 2012. ANZ-01
Growth, Yield, and Water Use of Wheat Under Elevated Carbon Dioxide
Project Leader: Glenn Fitzgerald, Victorian Department of Primary Industries, Horsham, Victoria.
E-mail: glenn.fitzgerald@dpi.vic.gov.au.
Project Cooperators: Saman Seneweera (The University of Melbourne), Garry O’Leary (Victorian Department
of Primary Industries), Sabine Posch (The University of Melbourne), and Michael Tausz (The University of
Melbourne).
A significant effect of global warming—both as a cause and an effect—is an increase in global
atmospheric carbon dioxide concentration [CO 2 ]. Elevated [CO 2 ] increases plant growth and yield—termed
the “fertilization effect” because in C3 plants photosynthesis is not carbon dioxide saturated. The extra
growth requires additional N, and other nutrients, even though the amount of N in C3 plant tissue grown for
long periods under elevated [CO 2 ] declines, which then results in lower grain N (i.e. protein) content. The
plants become more efficient for the amount of N contained, but if the N decline did not occur, the yield
response would be larger. There is no information to guide agronomists and breeders towards managing and
developing improved varieties to meet and maximize this response. The project has moved from quantifying
and modeling the effects of climate change, to investigating the underlying physiological responses and the
variation within wheat in those responses so that improved cultivars can be designed for the future.
Seven cultivars of spring wheat were grown at either ambient [CO 2 ] (~384 µmol/mol) or elevated [CO 2 ]
(700 µmol/mol) in temperature-controlled glasshouses under natural sunlight. Yields increased by 38% on
average but some cultivars showed a larger photosynthetic response than others. It was shown that the leaf N
content and leaf thickness were correlated with grain yield response. Results of this study show cultivars of
wheat do differ in their response to elevated [CO 2 ] and there are traits that can be used to select cultivars to
IPNI Interpretive Summaries 55