Better Frost Decisions September 2022

ISSUE 5 | SEPTEMBER 2022

BETTER FROST DECISIONS Knowledge to inform grower and adviser decisions for pre-season planning, in-season management and post-frost event responses

IN THIS ISSUE The chance of spring frost and which regions rank the coldest Preparing for frost response New frost work from GRDC

Cold Mallee morning on vetch

WELCOME

Frost in spring of 2022 is best understood as a random process Peter Hayman and Dane Thomas, SARDI Climate Applications Frost risk matters in every season, but it is difficult to imagine a season where the stakes are as high as 2022.

The extremely high input costs can only be offset if grain is harvested and sold for potentially good prices. Even urea prices of $1300/tonne can be profitable with wheat prices at $400/tonne, providing the 40 to 50% of the nitrogen fertiliser is recovered in the grain.

A badly frosted crop has low fertiliser recovery as the price received from the reduced yield won’t balance the high input costs no matter what happens to grain prices.

Table 1 (page 2) shows the number of nights colder than ≤2 degrees C in the last two years. We have used four sites with long term records so that we can get a sense of the ranking of the last two years.

The six months from May to October shows the rankings. Firstly May, June and July have been grouped and then the business end of the season that includes August, September and October. The ranking and the long term average is based on 66 winters and 65 springs for Yongala, Kyancutta and Mildura (since 1957) and 53 winters and 52 springs for Ararat (since 1970).

Continued....

The second issue for the year comes as we enter September, a month that brings nervous tension to many growers that live and farm in frost prone regions.

We continue our regular catch up with Dr Peter Hayman and we also check in with FAR Australia's Research Director Dr Kenton Porker to hear about the new GRDC investment in frost research.

In our podcast we also chat to Agriculture Victoria Research Agronomist Dr Jason Brand and then head to the EP to hear the latest on the season and the frost site at Tooligie with Josh Hollitt, Josh Hollitt Consulting.

Next issue due October 2022.

Table 1 Number of nights <= 2 degrees C

Yongala in the Upper North of South Australia is the coldest site followed by Ararat, Kyancutta and then Mildura.

Local experience will point out that Yongala is in an elevated valley and can be bitterly cold. As expected, there are more frosts in the three months of May, June and July than August, September and October. In 2021, at all four sites, May to July had fewer cold nights than average and this was most likely due to the very wet July last year.

The 11 cold nights at Ararat was less than half the average of 24 and the second lowest number since 1970.

Only Kyancutta on EP had more cold nights in August to October, the other three sites experienced average or less frosty finish to the season.

The start of this winter cropping season (May, June and July) has recorded more cold nights at Kyancutta, the average number at Yongala and fewer than average at Mildura and Ararat.

An obvious question is what will happen in the important months of August to October when frosts can severely impact yield.

A reasonable question is whether there is any relationship between the number of cold nights early in the season (May June July) and later in the season.

In other words, should we expect some persistence or memory in the seasonal frostiness whereby seasons that start frosty tend to stay frosty.

It is not unreasonable to expect patterns arising from persistence in weather and climate. Some seasons seem to start raining and other seasons just seem to miss out.

Unfortunately using the 65 years at Kyancutta, Yongala and Mildura and the 52 years at Ararat we found no relationship. The r values that measure correlation are all low and indicate that this process is best understood as random.

As we showed in the last newsletter, there is not a strong signal for frost from a negative or positive Indian Ocean Dipole.

In the late 1990s, the climate scientist Neville Nicholls used to include a quote on his email signature from the Dr Who movie “I love humans, they can find patterns in anything”.

All of us, researchers, agronomists and farmers are good at recognising patterns, that is one of our superpowers as humans. The problem is that we look for pattens that are not there in tea leaves, palms of hands and weather records.

Continued....

Vegetative frost on barley, morning of -2 degree C

Weather records are extremely useful to learn from the past, to put seasons in context and compare sites. These records help us say something meaningful about frost risk and, with records of rainfall, evaporation, radiation and hot days, to calculate optimal flowering windows.

Because we have the weather records we can use statistics to challenge our intuition that a frosty start to a year means something about the finish.

Unfortunately, frost remains a real risk for the coming spring and it is best understood as random.

Following developments such as the new GRDC project led by Dr Kenton Porker on manipulating crops within the season may suggest some opportunities for novel in-season approaches that may help growers avoid frost damage.

Because we don’t know what will happen in spring it is wise to consider ways to prepare for a ‘softer fail’ rather than a ‘hard fail.’ This will differ on each farm. In some cases, working out hay and grazing options and being prepared to make an assessment of damage after a cold night.

Projects such as this that keep you in touch with grower groups and the latest science on frost are valuable.

New podcast release Better Frost Decisions Podcast out now!

This month we chat to: Our regular Dr Peter Hayman, SARDI Climate Applications is back to compare the temperature in different regions. Where it is likely to be the coldest and how are the regions fairing on the frost scale in 2022?

Will this affect the incidence of frost in spring?

Dr Jason Brand, Pulse Research Agronomist Agriculture Victoria, who is in the field in the Vic Mallee inspecting lentil crops. How do pulses tolerate frost?

Dr Kenton Porker, Research Director FAR Australia, on new management strategies that will be investigated as part of GRDC's new investment in frost.

Josh Hollitt, Josh Hollitt Consulting, to get an update on the Tooligie site on Eyre Peninsula and hear how the season is tracking.

Better Frost Decisions on Facebook Be prepared for a timely frost response If you live and farm in a frost prone environment you know all too well that a crop can be there one spring day and gone the next if an untimely frost event occurs.

To support growers through this nerve wracking time of year, the Better Frost Decisions Facebook page has been launched to provide you with access to the information you need when you need it.

Barley frosted at grain fill

Over the next few months this group will provide you with the resources to: identify frost damage assess your options for frosted crops plan for next season reflect and review on the frost event(s) and your response.

Frost experts and agronomists are on standby to answer questions and share ongoing content using this online platform to support southern region growers in the field.

Join our online frost community so when it comes to making the tough decisions on frosted crops you're not alone!

We hope you don’t need us, but if severe frost does strike this year, this group is here to provide you with up-to-date information about identifying and responding to frost during the 2022 season, as well as to help you plan for future seasons.

Can we reduce frost damage in early sown crops and high-risk areas with in season management tools?

The new GRDC investment in frost is taking a different approach to frost research, looking beyond genetic screening to investigate management options that may become 'farmer ready' within a short time frame if proven to be successful.

The new project, involves some 13 research and farming system group collaborators is led by FAR Australia's Research Director, Dr Kenton Porker.

By 2025, the project aims to validate and quantify the opportunities in adopting a range of different in season management practices to avoid frost damage nationally.

Some of the practices that will be tested in conjunction with altering genetics and sowing date and include: mechanical and chemical defoliation the use of growth regulators the use of cryoprotectants and bactericides other agronomic management decisions & novel practices.

Growers may have heard about one or more of these strategies in the past, with various claims made about their effectiveness when it comes to mitigating frost damage.

However, this project will take a deep dive into the different approaches and fine tune strategies that may have potential.

As strategies are climate dependent each region will require different strategies dependent on germination opportunity, heat and drought risk and the ability to produce biomass at sub optimal conditions.

This work will complement other GRDC research investments, with much work still to take place in beating frost.

Dr Kenton Porker is leading the new frost project.

FAR2203-001RTX "Enhancing Frost Tolerance and/ or Avoidance in wheat, barley and canola crops through in season agronomic manipulation A strong collaborative research team will be able to validate strategies in different environments.

Collaborators: FAR Australia, DPIRD, CSIRO, Living Farm, University of Adelaide, SARDI, NSW DPI, Charles Sturt University, EP Ag Research, Birchip Cropping Group, Mallee Sustainable Farming, Frontier Farming Systems, Federation University.

Tactics to minimise frost damage on the Eyre Peninsula update The frost trial site at Tooligie explores an array of frost management strategies across two different frost risk zones.

These strategies include soil amelioration, phenology, time of sowing, nutrition, preventative foliar applications and crop type.

18 different cereal varieties and 16 different mixtures were sown on both 19 April (reaching GS31-32 by 23 June) and on 18 May (reaching GS31-32 by 3 August).

Since reaching growth stage 31 the Kyancutta BoM weather station has recorded 6 frost events. Down in the canopy level at Tooligie, tiny tags recorded 19 events.

Tiny tags were also placed 5cm below the soil surface. At the ground level, temperatures were warmer in the evenings and cooler during the day, when compared to the air around it.

A 50cm deep Bednar ripper strip was run parallel to both the high and medium risk trials.

The canopy temperature in the ripped strip has been around half a degree warmer most nights and especially warmer during the more severe frost events (28 June and 6, 9, 10, 14, 15, 18, 19, 21, 24, 27, 28 July) (Figure 1.).

GRDC Project code: AIP2203-001SAX Prepared by Rhaquelle Meiklejohn, EPAG Research

Figure 1. Difference in canopy temperature as a result of amelioration (ripped – unripped). The fluctuations follow a daily cycle, demonstrating warmer nights and cooler days.

Above: Frost damage already visible in August in varieties like Calibre and Vixen in the first time of sowing (19 April).