Northern frost risk
The Grains Research and Development Corporation (GRDC) has invested around $13.5 million in more than 60 frost-related projects since 1999, in recognition of the severe impacts of frost on crop production.
Queensland Alliance for Agriculture and Food Innovation (QAAFI) Research Scientist Jack Christopher says his GRDC funded frost research shows that while warmer temperatures may reduce the frequency of frost events, it also increases the rate of crop development bringing crops to the susceptible, post heading stages earlier.
“These results indicate that continued research into reducing frost risk remains a high priority despite increasing temperatures,” Dr Christopher said.
“Indeed, the situation analysis of national frost impacts we have undertaken indicates losses remain substantial, at around 10% even where people are using best practice management techniques.
“That figure is even higher in the northern grain region as potential yield is also reduced due to late sowing.”
Analysis led by Dr Karine Chenu of QAAFI used data collected from nearly 3000 weather stations across Australia to determine the frequency of frost events in each cropping region.
"We wanted to quantify losses for each region to guide research investments chasing frost resistance versus frost avoidance,” Dr Christopher said.
"By using the frost damage and climate data collected at research sites in past years we can determine the minimum temperature required to produce frost damage in each of the major cropping regions.”
Dr Christopher said that work led by Dr. Troy Frederiks at the Department of Agriculture and Fisheries Queensland indicates that the current best strategy to maximise long term crop yields was to time crop heading, flowering and grain filling to target the short window of opportunity after the main frost risk period has passed and before day time maximum temperatures become too high.
“Variety guides and decision support software are useful in matching cultivars to sowing opportunities in local regions, and a historic comparison of on-farm and district minimum temperatures can allow growers to fine-tune management to better suit their particular property and individual paddocks.
“Mixing up sowing dates and using crops with different phenology can help to spread risk.
“In-crop temperature measurements are useful to determine whether a crop may have been exposed to damaging temperatures,” he said.
If crop temperature at canopy height drops below -3.5C after awn emergence, crops should be assessed for damage.
But Dr Christopher warns current variety ratings based on floret damage aren’t always useful, as floret damage ratings are yet to be correlated with more significant head and stem damaging frosts.
“Results from this frost situation analysis will provide valuable insights, allowing GRDC to focus research resources,” he said
“By quantifying the economic impact of frost the potential impact of research into improved frost management and genetic frost resistance can be estimated.
“They also provide valuable insights for managing frost risk now.”
Growers can hear more about Dr Jack Christopher’s frost research at the Gilgandra grower update on July 20.
Dr Jack Christopher,
Queensland Alliance for Agriculture and Food Innovation
07 4639 8813
0429 897 129
GRDC Project Code UQ00071