Dr. Peter Heyman and others explain how grain growers should think about frost risk. A 65-year local record shows the worst frost window runs from late September through late October. The best approach balances frost danger against heat and moisture risks, shaped by your experience, business situation, and personality.
Questions this video answers
65 years
Late September to late October
128 pages
About 10% frost damage
Chapters
Frost risk management is very much an individual thing. So how should a grain grower approach it? What shapes a grower's attitude to frost risk management is a complex blend of their experience, business constraints, age and personality. Climate application scientist Dr. Peter Heyman has been thinking about frost risk for much of his working life and says it requires a particular mindset.
One definition of risk is putting numbers on uncertainty. So we know there'll be frost, we don't know how many there'll be or when they'll be happening. What we have to do is say, can we put some numbers on that, on the likelihood of frost for different regions using the local records? And that helps us manage that risk because we're looking at the trade offs there.
Peter Heyman has crunched the numbers. This is an example of the earliest and latest days where temperatures were less than zero. A grain grower at NIL in Victoria can see over the past 65 years the frost risk spans from well before flowering to well after. However, the numbers indicate the greatest risk has occurred between late September and and late October. They are numbers that can influence future cereal variety choice and sowing decisions.
Why we need to think about risk too is because this is a very important trade off, because we would. In terms of taking some frost risk has real benefits. So there's rewards in terms of flowering wheat flowering earlier and the benefits of that. And there's a cost of taking no frost risk of flowering too late, in which case there's a heat stress and there's moisture.
Most frost risk management strategies are too conservative, with many growers making what they think are the right decisions. However, they're not necessarily good decisions. It's a realisation. A group of agricultural consultants came to after pooling their experiences and insights gained from working with grain growers in GRDC's grain and graze program.
The difference between a good decision and a right decision is a good decision is one where you understand the consequences. If you take that decision, you have least regret if it does go wrong. So you actually understand the downside and you try and make a more favourable outcome by putting strategies in place to help a right decision. In contrast, you can only tell in hindsight.
These insights have been published as a resource tool called Farm Decision Making. A wealth of information plus case studies are included in its 128 pages. It highlights key concepts considered essential to good decision making and how decisions are influenced.
I believe there are three influences on our decisions we call the head, the heart and the gut. The head's the logical or the facts and figures. The heart is around some of the emotional side of things. So your preferences, your values, your beliefs. And then the third one, what we call the gut, is around your intuition, and that's really based on the experience that you've had. And people's personalities will determine just how much of those three are really influential in making a decision.
Personality can have a major impact on a grain grower's frost risk plan. Peter Heyman recalls an old mentor saying the fear of frost can do more damage than frost itself and then challenge growers to take a calculated risk.
Bill Singel, who was an early researcher in Frost, used to say, if you have about 10% frost damage, that's often success because that means you've actually pushed up against the frost risk and had a bit of frost damage. So actually a little bit of frost damage means that you've actually pushed against it again.
Using NIL as the example, plotting the latest state of less than zero degree temperatures over the past 65 years helps reinforce the need to develop a frost risk management plan based on many years rather than the past few seasons and have a recovery strategy as part of the plan.
Engineers talk about fail safe systems and safe fail systems. So actually if there is a damage, can they put stock in? Can they cut for hay? And some of these, there's very clever ways that people in some situations are able to think through that.
Find more information on frost risk management tips and tactics for recovering from frost and farm decision making online at the grdc.
