THE grain industry is gearing up for climate change, with a novel research experiment at Horsham hoping to find out how crops cope under higher atmospheric carbon-dioxide levels.
According to Roger Armstrong, of the Department of Primary Industries' Future Farming Systems Research Division, climate change is expected to result in reduced rainfall and warmer weather, but one positive aspect is that higher atmospheric carbon-dioxide levels may increase crop growth.
Prof Armstrong heads a joint DPI and University of Melbourne research team looking at the carbon-dioxide fertilisation effect in wheat and field pea crops.
The team includes PhD student Raymond Lan, DPI soil scientist Nicole Mathers and DPI senior technical officer Roger Perris. With funding from the Department of Agriculture, Fisheries and Forestry and the Grains Research and Development Corporation, the research team is running a free air carbon dioxide enrichment experiment at the DPI's research farm near Horsham, using three different soil types.
While a number of FACE experiments are being run around the world, the Horsham project is believed to be the first of its type.
The research team took core samples 30cm in diameter and one-metre deep from soils at Horsham, Walpeup and Hamilton.
Prof Armstrong said this represented 99 per cent of the Victorian soils sown to grain crops.
Eight in-ground bunkers were established in a wheat paddock, each holding 50 "cores" from a mix of the three soil types.
Half were sown to wheat and the other half to field peas.
Prof Armstrong said carbon dioxide was pumped out at plant-height level around the bunkers using a sophisticated network of pipes.
He said the aim was to subject the plots to atmospheric carbon-dioxide levels of 550ppm - the level expected in 2070.
He said current atmospheric carbon-dioxide concentrations were about 370-380ppm.
These had risen exponentially since the Industrial Revolution of the late 18th and early 19th centuries and are believed to be one of the causes of climate change.
Prof Armstrong said other FACE experiments had shown that soil nitrogen was progressively reduced with elevated carbon-dioxide levels.
He said the Horsham experiment was also looking at carbon and nitrogen cycling, particularly with the nitrogen fixation by field peas.
This 2009-10 harvest is the first year of what the research team expects to be a six-year project.
Data on crop growth; grain yield; nitrogen uptake; nitrogen fixation, above and below ground; soil water use; and root growth is handed over to the DPI's crop simulation modellers for analysis.
Prof Armstrong said the first year's results showed a 17 per cent stimulation in wheat growth but this was not significantly different statistically.
He said elevated carbon-dioxide levels had no growth effect on field peas.
"There was a slight stimulation of nitrogen fixation but it was not significantly different," he said.
"In the cores where we planted field peas, we will sow them to wheat next season to see what nitrogen benefits there are to the subsequent crop.
"What we expect to see over the years is that crops will become more and more nitrogen deficient because more and more nitrogen is tied up in the soil."
Prof Armstrong said unless nitrogen fertiliser was applied to crops, elevated carbon-dioxide levels were expected to result in less nitrogen available to plants.
