[ASC-media] WILL WA WHEAT YIELDS WEATHER CLIMATE CHANGE?: Crop Doctor
brendon at iinet.net.au
Wed Dec 12 02:00:36 CET 2007
WILL WA WHEAT YIELDS WEATHER CLIMATE CHANGE? 12.12.2007
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While rain-fed agriculture is likely to remain a feature of WA broadscale
enterprises, the nature and stability of future climate has implications for
the grains industry long term.
Winter rainfall in the past 30 years has substantially declined in
south-west WA and this is consistent with global climate change models,
making WA a logical region for climate change studies.
A GRDC-funded research project has generated and tested daily climate files
for current conditions and for the middle of the 21st century.
Principal researchers, Dr Imma Farre and Dr Ian Foster of DAFWA, used the
data to identify changes in wheat production, or quality, from current to
Dr Foster indicated that seasonal risk statistics, such as the timing and
occurrence of frost events, were derived from daily temperature extremes.
Eight locations represented the range of rainfall zones (high, medium, low)
and agricultural regions (north, central and south). Three typical soil
types sandy, duplex and clay, with 59, 86 and 116mm of plant-available
water, respectively, were chosen.
Simulated climate data demonstrated that for the mid 21st century in
southern WA, temperature and carbon dioxide concentrations would increase
and growing season rainfall decrease.
Total annual rainfall reductions tended to be higher in the high-rainfall
locations. The highest seasonal rainfall reduction was predicted for April -
June, resulting in later sowing opportunities and decreasing expected
Yield consistently declined in the low rainfall zones and increased in some
high rainfall locations and waterlogging-prone soils. Heavier soil types,
such as clay, were more vulnerable to climate change than lighter soils.
In most locations, the positive effect of elevated carbon dioxide on crop
yields was more than offset by the negative effect of increased temperatures
and lower rainfall. Increasing atmospheric concentration of carbon dioxide
would also lower grain protein levels, if no changes to fertiliser
management were considered.
Dr Farre indicated that adjusting farm management practices, such as
fertiliser management and cultivar choice, may be necessary to counteract
some of the negative impacts of climate change.
She also suggested that future improvements to climate models should add
confidence to regional climate projections. Data obtained in the GRDC study
forms an objective basis for a range of future impact and adaption studies.
The Crop Doctor is GRDC Managing Director, Peter Reading, Tel 02 6166 4500
More Information: Dr Ian Foster, Tel 08 9368 3642, Dr Imma Farre, Tel 08
Brendon Cant & Associates
Public Relations & Marketing
4 Gugeri St
Claremont WA 6010
Tel 08 9384 1122
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