The impact of frost appears to be worsening for growers on South Australia’s central and lower Eyre Peninsula, but a new GRDC investment is looking to equip the industry with greater knowledge and skills to mitigate the effects of the climatic scourge commonly known as ‘Jack’.

Agricultural Innovation and Research Eyre Peninsula (AIR EP) is delivering the ‘Tactics to minimise frost damage on the Eyre Peninsula’ investment through GRDC’s National Grower Network (NGN) over the 2022 and 2023 seasons, with the main trial site at Tooligie Hill - on the border of the central and lower EP areas.

AIR EP executive officer Naomi Scholz says the temperature at Tooligie Hill plummeted below zero on 38 occasions in 2021, making it an ideal location for a frost trial.

“We have partnered with EPAG Research to sow two trial sites on that property, one of which is on sandy soil in a ‘high-frost-risk’ location and another in a zone of the paddock with a higher clay content in a ‘medium-frost-risk’ location, with mirrored treatments,” she says.

“The ultimate aim of the project is to increase knowledge and give growers the confidence to adopt and implement the best management practices to minimise the impact of frost on profitability.

“As part of the project, we have established a project steering committee of local advisers, plus Mick Faulkner from the Mid North Frost Learning Centre, to provide advice on trial and demonstration site location, questions to answer and frost management activities to test.

“They will also facilitate frost discussion groups made up of local farmers impacted by frost to discuss various strategies available to mitigate frost risk and introduce them to strategies being trialled in this project.”

Theories on incidence

One of the project steering committee members is Michael Hind, an agronomist with Bates Agricultural Consulting. Mr Hind says there are several theories as to why the incidence and severity of frost seems to be worsening in the area.

“There are farms to the north and the south of the Hincks Wilderness Protection Area which have been affected by frost in five out of the last six years,” he says.

“In some years, the frosted areas have been a total wipe-out, whereas in other years the growers have managed to reap a small amount of grain.

“One of the theories is that the native scrub from Hincks is affecting the climate and airflow around it, or it may have something to do with the topography of the area.

“With this project, we want to find out why these frosts are happening and then perhaps we can manage it better.”

Limited options

Mr Hind says some of the more-traditional methods of frost management – cutting the affected area for hay or grazing it with livestock – are not an option for many growers in the area given the move to continuous cropping and a lack of access to export hay markets.

Instead, the trials will examine different times of sowing and crop phenology, crop types, nutrition treatments and the effects of soil amelioration in mitigating frost damage.

The project arose from a smaller GRDC investment in 2021 which enabled EPAG Research and AIR EP to engage Dr Peter Hayman from the South Australian Research and Development Institute. Dr Hayman’s knowledge was used to set up data loggers in frost-prone areas, providing valuable local data.

“A lot of climate data for the central EP comes from the Bureau of Meteorology’s site at Kyancutta, which is more than 90 kilometres away from Tooligie Hill,” Mr Hind says. “From those data loggers, we were able to see the severity of the 38 different frost events at Tooligie Hill in 2021, which got down to -6°C.”

A significant element of the project is the establishment of satellite demonstration sites within the boundary of Karkoo to Wharminda to Mangalo to Kimba to Warramboo.

“The trial design and treatments have very much been driven by grower feedback and by a much-smaller trial we conducted with GRDC investment in 2021,” Mr Hind says.

“We will be hosting a spring field day at the main site at Tooligie Hill this year and next year, which we expect will attract considerable interest from growers.”

More information: Naomi Scholz, 0428 540 670, eo@airep.com.au; Michael Hind, 0448 873 338, michael@batesag.com

Warm reception for local research

Over the past five seasons, Tim Zacher has seen the frosted area on his properties increase with no clear explanation as to why.

For that reason, he welcomes GRDC’s investment in local research to determine the best management strategies and minimise the impact of frost on growers’ bottom lines.

Host grower Tim Zacher with children Kate and Nathan at the Tooligie Hill trial site. Photo: Supplied

Tim is hosting the main demonstration site for GRDC’s ‘Tactics to minimise frost damage on the Eyre Peninsula’ investment over the 2022 and 2023 seasons on leased country at Tooligie Hill.

Together with his family, Tim grows wheat, barley, canola, peas and lentils. He estimates that the average frosted area on his properties makes up 15 per cent of his total cropped land, with about 30 per cent of the farm where the trial site is located experiencing major frosts.

“The lower-lying areas are always the worst-affected, as we have undulating country where cold air can get trapped in the hollows, and areas with sandy soils are always affected,” he says.

“It’s not just the area of frost expanding, but the duration of frost events as well. Last year we had consistent frost events spanning a six-week period, running into October and November.”

With no livestock to graze frosted crops and no nearby hay market, Tim has no option but to take crops through to harvest and incur a significant yield penalty.

“We have previously cut hay in 2018 and 2019 when hay prices were high and we could mitigate the hay contractor and transport costs, but hay prices have since fallen so we have stayed away from it in the years since.

“The fact grain prices have firmed up in recent years is another reason we choose not to cut hay.

“We’re trying some new strategies here, which include different times of sowing and variety choice. One of our early sown wheat paddocks in a frost-sensitive area has three different varieties in it – Vixen (PBR), Scepter (PBR) and Denison (PBR) – so we have some variation in flowering time.

“We have also done some deep ripping with a Bednar Terraland in frost-prone country, which we used a contractor for. Visually, the crops seem to perform better through the frosts but I don’t have any long-term data to see an improvement in yield.”

While Tim knows he will not be able to eliminate frost damage completely, he is hoping the research will arm him with more knowledge regarding the agronomic options available to lessen the impact.

“Ultimately it would be great to find varieties or crop types that are more resilient or resistant to frost on the central EP,” he says. “The question around the effect of deep ripping is one I find really interesting, so hopefully the research will be able to quantify that.”

More information: Tim Zacher, 0448 873 338, tkzacher@bigpond.com