Three pronged initiative tackles frost
Frost has emerged as the biggest risk to Wickepin grower Shane Hill’s cropping business in the past 10 years, with frost damage causing average annual yield losses of up to 25 per cent.
Mr Hill and his wife Kerry farm 5500 hectares in the Western Australian grainbelt with Mr Hill’s brother Dean and his wife Karen. Their cropping program comprises 3500 hectares of wheat, 1000ha of canola, 400ha of lupins and 400ha of feed barley.
The Hills are trialling several different management strategies to help mitigate frost risk and are taking a keen interest in the work being undertaken through the Grains Research and Development Corporation’s (GRDC) National Frost Initiative (NFI) by their local grower group, the Facey Group.
GRDC estimates that the direct cost of frost to Australian grain growers is about $400 million per year across the nation.
With the exception of 2013 and 2014, when there was almost no frost damage on his property, Mr Hill says frost has continued to bite into his crop productivity and yields.
“Probably through the 1990s, we had a couple of severe frost incidences but then in 2005 we got hammered by frost – it hit about 50 per cent of our wheat yield,” Mr Hill said.
“In 2008, it was probably about 70 per cent.
“Since then, in 2011, we had fairly significant frost damage in places; 2012 was bad; and then again in 2015 we had more damage than I thought - maybe 10 per cent yield was hit by patches of frost.”
In 2012, Mr Hill said he calculated that frost was costing his cropping operation about 0.8 tonnes/ha per year across their long-term yield average.
“After a couple of reasonable years, it’s dropped back to about 0.5t/ha that we’re losing - that’s 25 to 30 per cent of our yield, on average,” he said.
“Our average yield prior to 2013 was probably about 1.7t/ha (five-year average), which should have been closer to 2.4t/ha if we didn’t have any frost.”
Mr Hill said research into frost mitigation tactics was vital, but conceded no ‘silver bullet’ would address this issue - with a package of various measures necessary to reduce risk.
“It seems that every frost is different and every year is different,” Mr Hill said.
“I don’t think there’s any one management tool that’s 100 per cent effective.
“Delaying sowing to miss the cereal flowering window is probably just as fraught with danger in terms of hitting a heat, moisture and drought stress period at the end of the year.
“I’ve found that frost in the flowering window is not the one that costs our business heaps of money, it’s more dangerous to have a frost at grain-fill later on.
“And we’re finding that quite often it’s the later sown crops that get smashed more with frost than the early sown crops.
“This year, our worst affected farm was the farm we seeded last, and in 2012 that was the case as well.”
Management changes the Hills have made to help mitigate frost risk have included changing wheat varieties from Wyalkatchem to the less frost-susceptible Mace.
“We’ve altered our rotations a bit, in that there’s definitely more barley sown on some of the frost-prone areas,” Mr Hill said.
The Hill family has also experimented with stubble retention and stubble burning.
“The variety ranking of frost susceptibility is potentially a valuable tool and stubble management is interesting and worth investigating,” Mr Hill said.
GRDC has long acknowledged the severe implications of frost on crop production and since 1999 has invested about $13.5 million in more than 60 frost-related projects nationally.
In 2014, GRDC increased investments into frost research through the establishment of the five-year NFI.
This is an integrated program with a three-pronged approach addressing genetics, management and environment to mitigate the effects of frost.
The focus of genetics research is to develop more frost-tolerant wheat and barley germplasm and rank current wheat and barley varieties for susceptibility to frost.
NFI steering committee chair and GRDC Western Regional Panel chairman Peter Roberts said besides the direct costs of frost, growers were further losing yield trying to farm around the issue.
He said growers in WA, particularly, were sowing later to try to avoid a September frost.
“The big kicker for us in the future is to be able to take advantage of long seasons - we know that’s where the increased yield is,” Mr Roberts said.
“Work being done by the CSIRO and other researchers has shown that the longer the season, the longer the season variety, the higher the potential yield.
“Growers don’t take advantage of that because they’re worried about getting hit by frost, so we lose every year by sowing later.”
Mr Roberts said gains were already being made through genetics research being carried out by the NFI.
“Should we be able to find genetic variation in certain varieties, particularly wheat or barley, then the next question is, can we exploit that,” he said.
“Certainly from a variety or genetic point of view, we’re not yet at any stage where we can say that a grower should grow one variety over and above another to avoid frost totally.
“The project has allowed us to rank varieties in terms of frost tolerance and these are miniscule differences, but every quarter of a degree is helpful when you’re out there in the paddock.
“We do know now how to identify frost damage in crops a lot better than we did five years ago.
“Having a farming system that delivers profits each year is the aim of the game, rather than trying to hit the highs and take out the lows. It’s about trying to manage that risk.”
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