South Perth, Western Australia
February 14, 2008
Crop simulation modelling using
climate change predictions points to increased risk to wheat
production for the Western Australian wheatbelt according to the
Department of Agriculture
and Food.
 Speaking
today at the department’s Agribusiness Crop Updates, crop
modeller Imma Farré said future climate, without allowing for
adaptation strategies, would see a decline in average wheat
yields for most of the wheatbelt.
However, she said future yields could increase in high rainfall
regions and on soils prone to waterlogging, where the decrease
in rainfall would mean a reduction in waterlogging.
“Climate change projections for the mid 21st century for
southern Western Australia indicate an increase in temperatures,
a decrease in rainfall and higher CO2 concentrations from
current conditions,” Dr Farré said
“These changes, without considering changes in technology,
varieties and other adaptation strategies, show an increase in
the frequency of years with low wheat yields and a decrease in
the frequency of high yielding years for most of the wheatbelt.”
Dr Farré said downscaled climate data from a tested Global
Climate Model was used as input into a crop simulation model to
evaluate wheat yields under future climate in a range of
representative locations and soil types.
“Simulations were run for 27 wheatbelt locations and two soil
types representing a range of rainfall zones and agricultural
regions,” she said.
“The simulations were run assuming present technology, current
varieties and current agronomy packages.
“The results showed heavier clay soils were more vulnerable to
climate change than light textured soils and would experience
greater yield penalties.
“Low and medium rainfall locations experienced a higher
frequency of low yielding years. Therefore wheat cropping on low
rainfall locations and heavy soils would be more risky than
under the current climate.”
Dr Farré said the largest projected yield decline in the future
was at Mullewa with a 24 per cent decline on clay soil and 17
per cent on lighter duplex soil.
“The largest projected yield increase was 14 per cent at
Wandering on duplex soil and seven per cent on clay,” Dr Farré
said.
“The projected yield decrease was due to lower rainfall and
higher temperatures, which caused shorter growth duration and
more water deficit in most locations.
“The yield increase in some high and medium rainfall locations
was due to the positive effect of increased CO2 levels and
reduction of waterlogging effects.
“In most locations, increased CO2 levels did not overcome the
negative effect of lower rainfall, delayed sowing and increased
temperatures.”
The department is working with its partners in Agriculture
Research WA and producers groups to examine climate change
projections and consider options for the future.
The Department of Agriculture and Food’s Crop Updates is
supported by the Grains Research and Development Corporation.
For more information on this year’s event visit
www.agric.wa.gov.au/cropupdates |
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