Australia’s yield potential suffered dramatic decline since 1990, a study has found

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Australia’s yield potential has experienced a 27% decline over the past 25 years despite the use of best practices and current technology, CSIRO scientists say.

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Their recent research found that Australia’s wheat-growing zone had suffered an average rainfall decline of 2.8 mm or 28% per cropping season, in addition to experiencing a maximum daily temperature increase of around 1 degree Celsius from 1990 to 2015.

CSIRO team leader Dr Zvi Hochman said the findings were consistent with the higher end of future climate change projections for the wheat zone over the coming 26 years, indicating a risk to the future prosperity of Australia’s wheat industry.

“Our results are a serious concern to the future livelihood of wheat farmers in marginal growing areas and to the Australian economy, as well as future global food security,” Dr Hochman said.

“Wheat farmers are making the most of developments in farming technology and adapting them to their needs. However, their best efforts are merely enabling them to keep pace with the impacts of a changing climate.”

The research, which analysed records from 50 weather stations across Australia’s wheat growing regions, also concluded that the loss of yield potential is not evenly distributed across the country’s wheat zone.

“While some areas have not suffered any decline, others have reduced yield potential by up to 100kg per hectare per year,” Mr Hochman said, stressing that annual variation in climate, yield potential and actual yields were normal in Australia.

Operating under the assumption that the climate trends observed over the past 26 years will continue at the same rate, the research also predicts that the national wheat yield would probably continue to fall even if farmers continued to improve their practices.

“We estimate that the recent average yield of 1.74 tonnes per hectare will fall to 1.55 tonnes per hectare by 2041,” Mr Hochman continued.

The study, published in the journal Global Change Biology, also suggests that the findings are broadly applicable to other cereal grains, pulses and oilseed crops, which grow in the same regions and same season as wheat.