This project is part of the GRDC Riskwi$e program.

The main themes UNFS will look to address for the RiskWISE project for 2024 will be focusing on:

• Crop selection and sequencing will primarily leverage existing information across long-term farming systems trials in South Australia and Victoria, which have a strong focus on complex decision making.
• Frost and heat effects: This sub-theme is included to identify, model, and understand key risks associated with climatic heat and frost effects on crops. This theme is influenced by both management strategies; including varietal selection and time of seeding, and climatic risk; seasonal outcomes of heat and frost, effects of autumn rainfall influencing emergence and flowering date. The impact of heat stress in spring, which has a large impact on yield cannot be reliably estimated prior to sowing but good decisions are made with a range of spring temperature conditions in mind. What is known is that as critical reproductive phases shift later in spring, the risk of heat stress increases. Crop and pasture species are largely spring types but sown prior to winter. While frosts are not predictable more than a few days in advance, the decisions are made weeks and months before. The damage from one hot day is never complete but the damage from one severe frost can be. The area impacted by frost can also increase exponentially with increasing frost intensity. Heat risk can be somewhat mitigated by sufficient PAW whereas frost damage is often independent of PAW status. Frost risk is more closely related to position in the landscape than heat risk.

This project is supported through funding from the SA Grains Industry Trust.

Project description: 

This project focuses on frost risk management and decision-making support for growers in the Upper North region. It includes the establishment of two replicated frost trial sites to explore the impact of crop type, variety, sowing time, phenology, and nitrogen treatments. Extension activities funded by the SA Drought Hub include local discussion sessions with growers, peer-to-peer workshops, a focus field day or bus trip incorporating multiple trial sites, a presentation at the UNFS Annual Expo on risk-related investment decisions, and a post-harvest review to evaluate trial outcomes and plan future activities. The project aims to build grower capacity in managing frost risk and making informed seasonal decisions.

Key achievements and results: 

2024 project update

In 2024, the project was well received by Upper North farmers, with strong interest in its focus on managing seasonal risk, particularly frost, amid challenging dry conditions. The dry season heightened the relevance of the RiskWi$e themes, prompting valuable discussions and learning through SA Drought Hub-funded activities. Farmers welcomed the opportunity to host a long-term frost trial site, with engagement and feedback indicating that the content was timely and useful. Trial management and the single extension activity were successful, though the dry season limited plot performance and restricted the number of events held at the site.

2025 project update

In 2025, the nitrogen trial site, co-located with the frost trial, continued investigating how different nitrogen rates and sowing densities of Calibre wheat impact productivity, profitability, and frost risk. Despite well-designed treatments (ranging from 0–300 kg/ha N and low vs high plant densities), extreme seasonal conditions- below-average rainfall, severe frost events, and high temperatures- led to poor crop performance across all treatments, with no significant differences in yield or quality observed.

Extension efforts have focused on helping farmers and advisors better understand the risks and rewards of nitrogen application under variable seasonal conditions. The frost trial has been well supported by the local farming and advisor community, with strong engagement through field events and crop walks. These activities have prompted meaningful discussion, highlighting continued demand for locally relevant strategies to manage frost and nitrogen risk in the Upper North.

Further information:

Read the project final report here: Frost Mitigation Strategies for the Upper North

Project Images