Lessons learned from the 2014 frosts: A grower case study
Author: Alistair Lawson | Date: 17 Nov 2014
Like many growers across southern Australia, frost has been yet another hurdle for Grant Alday to overcome in the 2014 growing season.
Farming in the Victorian Mallee between Sea Lake and Lascelles with his wife Bron, parents David and Jean and a full-time employee, frost has been something Grant has come to expect most seasons. However, it was the severity and extent of the frosts this year which brought parts of the Alday cropping program undone.
One particular area of the Aldays’ property has been historically prone to frost. It comprises a mixture of low lying sandy loam with the worst areas affected making up about 420 hectares, which is split into three paddocks. Those paddocks have sandy soils with a rolling topography that drains cool air in from a larger area.
In the past, Grant has tried to sow later on the problem area to mitigate frost damage, thinking that was his only significant option.
“We were stem frosted this year and as crushing as it was, it was the final straw in us deciding to search for some answers to the problems we have with those paddocks,” Grant said. “Our focus is still frost at flowering, despite the fact that stem frost was so widespread this season.”
This year, Grant recorded significant frosts on July 13 and over four consecutive days in the first week of August. The July frost caused obvious damage to lupins and one wheat variety quite quickly. By the time the August frosts expressed damage, the degree of loss was confronting.
“At that stage, we had not had a rain more than 7 millimetres since sowing,” Grant said. “Following those frosts, our lupins looked like they had been sprayed out – now they’re dead – and our Kord wheat had leaf burn straight away.”
Grant estimated about 1200ha of the property was severely frosted, of which 580ha of lupins and peas were sprayed out. Other crops to bear the brunt of frost damage included some of the barley and canola.
“In one area, there is 10 metres separating lupins from lentils and while the lupins were quite badly damaged, the lentils were fine,” Grant said. “My guess for that is the lentils must not have used up the soil moisture reserves like the lupins did.”
Assessment and economics
Damage, particularly in wheat, was assessed soon after the frosts. The degree of loss was difficult to assess over a number of locations, varieties, elevations and sowing dates.
“We could see there was plenty of loss, but we felt it was too difficult to appraise it accurately,” Grant said.
Knowing they did not have the biomass in the cereals for hay, Grant waited 2-3 weeks to better understand the damage.
“When we did go out and reassess, the damage was as bad as we thought it would be,” Grant said. “But the regrowth – especially from the Kord – was heartening and gave us hope of achieving some kind of yield.”
It was too late for Grant to change tack on inputs as 44 tonnes of urea had already been stored in the silo due to the dry winter. The frost damage, combined with moisture stress, also meant he had reversed his decision to bring in extra labour for harvest.
After weighing up the economics – and a ‘heads-up’ to the bank manager – Grant decided cutting the vetch for hay was going to be the only way they could recoup some of their costs. If the season had been better more of the vetch would have been brown manured.
“If income looks strong leading up to harvest I’m prepared to terminate vetch. It could go hay or be brown manured,” Grant said. “This year we ended up going for hay and I’m confident we’ve made the right call.
“There’s very strong demand around for hay and I’ve already sold some of this season’s cut for $240 a tonne.”
With the extreme frost events this year and the historic problem area, Grant decided enough was enough. In September, he and David headed across the border to Loxton for one of the Grains Research and Development Corporation’s (GRDC) frost workshops.
“We’re not just losing yield on those regularly frosted paddocks, we’re also losing quality,” Grant said. “It can take three weeks from start to finish to harvest a paddock because the regrowth from the frost damage is a real issue with logistics.”
As a result of the workshop, Grant better understands the production areas and make-up of his soils and the role they play in the severity of frosts.
He says he is considering delving some of the frost-prone country to see if he can bring some clay to the surface.
“There could be a double benefit in improving the soil moisture-holding capacity of the soil,” he said.
“We didn’t understand how important soil moisture is to releasing heat in freezing temperatures and giving the plant a buffer against frost. Even things like the colour of the soil – the white sands are more susceptible to frost damage.
“The other thing for us will be crop choice. We have persisted in growing a range of crops for a balanced rotation but we now understand that on a couple of paddocks this is a futile exercise. A narrow, low input rotation, with barley as the cornerstone will be the lesser evil. We won’t fight topography, we’d rather let the cold air drain than hold it back over a larger area.”
Grant is determined not to be too focused on frost as heat stress is just as big an issue. However, he said it is part of a package they needed to balance up.
“The GRDC frost workshop was a day well spent,” he said. “There were no silver bullets, however it gave us a deeper understanding of the causes of frost and provided us with a level of acceptance that frost is a part of our farming reality. We will now tailor our expectations and fine-tune our management practices to ensure a level of long-term profitability.”
More informationGrant Alday, Sea Lake, firstname.lastname@example.org