Tactics for minimising frost damage on Eyre Peninsula
Tactics for minimising frost damage on Eyre Peninsula
Author: Rhaquelle Meiklejohn, Brett Masters, Andrew Ware (EPAG Research) | Date: 23 Jul 2024
Take home messages
- High frost-risk areas on Eyre Peninsula can experience over 30 frost events from June to October.
- The large time range where damaging frosts can occur made it difficult to identify a flowering time or varietal phenology that was able to avoid frost damage in high-risk areas, but barley consistently experienced less damage than wheat.
- Canopy temperatures were consistently warmer in ameliorated sandy soils compared to their more natural state. However, this didn’t always reduce crop damage from frost events.
- Understanding your risk and zones within a paddock can support improved economic outcomes for growers through slightly different management.
Background
Extensive crop damage and financial losses were driven by frost events occurring across large areas of Central and Eastern Eyre Peninsula over the four years leading up to 2022. This GRDC-funded project aimed to enhance the knowledge and confidence of growers in the Eyre Peninsula's frost-prone areas, enabling them to adopt and implement practices that minimise the impact of frost on their profitability.
While growers understand that a complete solution to avoiding damage from frost is not currently possible, several strategies were identified by local advisors and growers for their potential to reduce frost damage. These strategies were evaluated to develop localised information on their optimal implementation.
Method
A combination of field trials located at Tooligie and grower paddock demonstration strips situated across the frost prone areas of Eyre Peninsula were used to evaluate a range of management strategies considered useful to reduce frost damage.
The strategies evaluated included:
- Determining whether longer-maturing varieties should be planted to avoid frost damage and whether fast-maturing varieties can be planted early to mature before frost events occur.
- Assessing the potential advantage of planting mixtures of varieties with differing maturity times. This approach could mitigate the impact of a frost event on one variety by having another variety with a different maturity time continue to grow unaffected.
- Investigating reports of certain nutrients and products that can be applied to crops to either enhance plant resilience against frost or reduce the levels of ice-nucleating bacteria.
- Exploring anecdotal evidence suggesting that soil amelioration practices on sandy soils might reduce frost damage.
These strategies were identified by a project steering committee, consisting of five experienced local consultants, in consultation with Mick Faulkner, a consultant from Mid-North South Australia with considerable experience in frost research, as well as frost researchers from Western Australia.
Results and discussion
Varietal Phenology
This trial showcased various sowing time and variety combinations available to growers to avoid frost exposure. Extending this work over two contrasting growing seasons highlighted the complexity of making these decisions without reliable frost and rainfall forecasts. Multiple frost events, both early and late in the season, made it challenging to consistently choose a wheat variety and sowing time strategy that reduced frost risk without the benefit of hindsight. Barley consistently achieved higher yields across several phenology and sowing time combinations than wheat in frosty environments.
Crop Type
In 2022, a trial of different crop types demonstrated the varied reactions of crops like canola, beans, lentils, and vetch to frosty environments. Growers and advisors sought to understand the relative frost damage risk across a range of break crops, especially given the growing importance of these crops in the farming system and the decline in livestock production. The recent expansion of lentil cultivation across central and upper Eyre Peninsula necessitated more knowledge about frost impacts on lentils and the suitability of alternative break crops such as faba beans. The work conducted in 2022 found that lentils experienced more frost damage than faba beans.
Nutritional Amendments and Ice-Nucleating Bacteria Control Products
This trial aimed to assess the value of various products purported to improve crop resilience to frost damage. Claimed mechanisms included foliar transpiration inhibition, nutrition-based sugar enhancement, plant health enhancement, floret sterility reduction, and antibacterial properties. Over two years in high frost incidence environments, none of the products demonstrated a yield benefit beyond correcting well-documented nutritional deficiencies, such as low potassium levels in sandy soils.
Zoning
Frost damage consistently affects certain landscape areas due to topography and air movement. Consequently, some paddock areas incur significant frost damage, while nearby areas remain unaffected. With advancements in precision farming equipment, growers can now manage high frost risk areas differently. To evaluate the benefits of such management, phenology, crop type, and nutritional amendment trials were mirrored in both high and moderate frost risk zones within the same paddock. Data showed that high-risk zones experienced more severe frost damage, and strategies like sowing longer-season wheat varieties (winter varieties) and various barley varieties had higher value in high-risk zones. This demonstrated the value of managing zones differently. Collecting data over additional seasons will be crucial for modelling yields and frost damage accurately, aiding growers and advisors in making informed management decisions based on frost risk.
Soil Amelioration
Anecdotal evidence from growers and previous research in Western Australia suggested a potential relationship between soil amelioration on sandy soils and frost mitigation. Data and observations from eight sites over 2022 and 2023 allowed direct comparisons between ameliorated and original soil compositions. Six of the eight site comparisons found that soil amelioration occasionally reduced daily canopy temperature fluctuations, with temperature differences increasing as conditions became more extreme. Some events were up to a few degrees warmer during the coldest overnight periods. Instances where amelioration did not result in warmer temperatures were found on heavier textured soils. Understanding the underlying mechanisms may help quantify the soil-temperature interaction level needed to reduce frost damage.
Conclusion
Between 2017 and 2021, large areas of Eyre Peninsula suffered from severe frost. In 2022 and 2023, various strategies were evaluated to minimise frost damage. These strategies included assessing varietal phenology and sowing times, using mixtures of varieties with different maturities, applying nutritional and ice-nucleating bacteria products, zoning, and soil amelioration.
The project found that high-risk areas can experience over 30 frost events from June to October, making it difficult to avoid frost solely through variety selection and sowing time. Identifying high-risk frost areas and managing them differently proved valuable.
Additionally, the project demonstrated that ameliorated sandy soils had warmer canopy temperatures during frost events.
Acknowledgements
The research undertaken as part of this project is made possible by the significant contributions of growers through both trial cooperation and the support of the GRDC, the authors would like to thank them for their continued support. The active participation and direction provided by the consultants (Mick Faulkner, Michael Hind, Ed Hunt, George Pedler, Josh Hollitt and Andy Bates) involved in the project is gratefully acknowledged. AIR EP for their support and facilitation of the project. The EPAG Research team for assistance with the management and collection of data across the trials and demonstration sites. The assistance of the multiple growers who hosted trials and demonstration sites over the two years the project ran is also gratefully acknowledged.
Contact details
Rhaquelle Meiklejohn, Research Agronomist, EPAG Research
7 Seaton Avenue, Port Lincoln
0497 070 638
rhaquelle@epagresearch.com.au
GRDC Project Code: AIP2203-001SAX,