Australia’s wheat yield potential has declined 27% over the last 25 years according to new research from CSIRO scientists.
Despite wheat yields tripling (due technological advances) between 1900-1990, there was no increase at all from 1990-2015.
The study found Australia’s wheat-growing zone has experienced an average rainfall decline of 2.8 mm (or 28%) per cropping season, and a maximum daily temperature increase of around 1℃ from 1990 to 2015.
If accurate, Australia’s $5 billion per annum wheat industry, which contributes around 12% of wheat traded worldwide, could be at serious risk.
“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,” CSIRO team leader Dr Zvi Hochman said.
“[However] wheat farmers are making the most of developments in farming technology and adapting them to their needs,” he added.
Farmers are currently managing to maintain yields at 1990 levels of around 1.74 tonnes per hectare, nation wide, allowing growers to close the gap between potential and actual yield.
“1990 was a watershed year for Australia’s wheat industry, with a continued decline trend in yield potential since that year,” Dr Hochman said.
The study also found the loss of yield potential was not distributed evenly throughout Australia, with some areas not being affected at all, while others reducing potential by up to 100kg yearly.
Wide annual variation in climate, yield potential and actual yields are normal in Australia.
“Assuming the climate trends we have observed over the past 26 years continue at the same rate, even if farmers continue to improve their practices, it is likely that the national wheat yield will fall,” Dr Hochman said.
“We estimate that the recent average yield of 1.74 tonnes per hectare will fall to 1.55 tonnes per hectare by 2041.
“The 2016 season is expected to result in a bumper crop, however, our preliminary estimates show that yield potential in 2016 was about the same as in 2010.
“So, yield potential was high, but not exceptional.
The CSIRO noted although the study focused on wheat, the findings would be broadly applicable to other cereal grains, pulses and oilseed crops, which grow in the same regions and same season as wheat.