Always learning growing Canola
- By: "Farm Tender" News
- Cattle News
- May 18, 2018
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In 1991, canola plantings across Australia covered 151,000 hectares. By 2016-17 – just 25 years later – that area had ballooned to 2.3 million hectares, with growers producing more than four million tonnes of the oilseed.
According to the Australian Oilseeds Federation, more than half of total production is exported to Europe and countries such as Japan, Pakistan and Bangladesh, contributing almost $1 billion to the Australian economy.
These days, there is no denying the importance of this small, black oilseed to the Australian grains industry. While 1991 may seem a lifetime ago to some, in terms of best practice agronomy adoption, canola is still considered the ‘new kid on the block’.
Agronomist and GRDC Western Panel member Michael Lamond says canola has been a very profitable crop for many Australian growers in the past two decades, but it can cause major headaches in more challenging years, particularly for growers in less-reliable rainfall regions.
In Western Australia, 2017 was one of those challenging years, with high summer rainfall in many areas giving growers confidence to plant early. But minimal or no opening rains saw staggered germination of canola crops across the wheatbelt.
Mr Lamond says the flow-on effects of staggered germination were significant when it came to managing the crops’ agronomy throughout the season. “We had a really tough start to the 2017 season, so growers were trying to establish canola in a drying profile,” he says.
Staggered germination meant plants in the same paddock were sometimes eight weeks apart in maturity. “As a result, some growers did not know when to spray for weeds, when to control disease and when to apply fertiliser right throughout the season,” he says.
“Ultimately, what we saw in many farm businesses was that growers backed off from all of those pest and weed controls, and reduced their fertiliser applications, so these crops could not take advantage of the soft finish.”
As is the case with other crops, the timing of nitrogen application is critical. “In WA, growers tell me that liquid nitrogen plus sulfur at the start of flowering beats any granular fertiliser up-front,” Mr Lamond says.
He says 2017 demonstrated the level of risk involved in growing canola. “Regardless of the season, if you are going to plant canola, you have to commit the dollars to the crop to ensure you achieve full potential at harvest time.
“We saw a big range of canola yields, even within individual farm businesses, and part of that was due to finishing rains and the season, but some of that was also due to the decisions made during the season.”
Seeding depth
After the tough start to the 2017 season, Mr Lamond says growers were asking questions about seeding depth. “It is a common view that canola should only be put down about 10 millimetres, but with subsoil moisture underneath and a drying topsoil, the conditions last year really opened up the conversation about how deep you can plant canola and still see a germination.”
Many might have been tempted to go deeper than 10mm, particularly given the warm conditions, he says.
WA Department of Primary Industries and Regional Development (DPIRD) crop agronomy research officer Martin Harries says a $5.9 million GRDC investment into the Tactical Break Crop Agronomy Project in WA has demonstrated the best germination results were achieved at seeding depths of about 10mm. Total GRDC investment into tactical break crop agronomy over six years has been $7 million, with $6.5 million co-investment from WA DPIRD.
Seeding depth trials have been sown at Eradu, Mingenew, Binnu, Dalwallinu and Merredin over the past five years.
“Farmers can play with seed depth a bit to try and chase moisture to around 20mm but, generally, if sowing depth increases too much, the research shows that establishment rates will be reduced,” Mr Harries says.
“If you are looking to chase moisture below that traditional 10mm level, our trials showed that the hybrids performed better than the open-pollinated varieties when sown deeper, due to their larger seed size.”
NSW experience
Research by the NSW Department of Primary Industries in Coonamble, Nyngan and Trangie has supported the WA findings.
Wagga Wagga Agricultural Institute agronomist Rohan Brill says while maximum recommended sowing depths are different for growers in the western region than those in the eastern states, the findings in the two regions were consistent.
“The research has shown that, ultimately, early-sown canola yields better in most cases,” Mr Brill says.
Mr Brill and Mr Harries agree that if you need to chase moisture to ensure early establishment, the key is in the size and quality of the seed.
“Since the soil surface dries out more rapidly in early to mid-April compared to mid-May, seed may need to be planted slightly deeper than optimal,” Mr Brill says.
“But as with the WA research, our trials showed that all varieties had reduced establishment at the 5 centimetre sowing depth compared to the 2.5cm sowing depth, with the exception of Pioneer® 44Y84 (CL), which had the largest seed.
“At the 7.5cm sowing depth the difference between varieties and seed size became more marked, as the largest-seeded variety achieved 50 per cent establishment compared to 20 per cent establishment for the smallest-seeded variety.”
In this early planting situation, Mr Brill says, growers should pay close attention to seed quality. “Sowing large seed (more than five grams per 1000 seeds) results in an increased likelihood of achieving an adequate establishment.”
He advises growers who retain open-pollinated seed on-farm for their own use to clean the seed with a 2mm screen.
Mr Lamond agrees that the conditions have to be right for growers to consider deeper sowing and cautions that any paddock where this deeper planting occurs must have good cover to minimise wind erosion.
“I have heard stories where canola seed planted deep in a very exposed paddock had to battle with wind erosion where soil covered-in the furrow, making it almost impossible for the seed to germinate. This is an important consideration when looking at which paddocks you can apply this strategy to,” he says.
Low-rainfall zones
Mr Lamond says it was a tough lesson for many growers with heavier soils in low-rainfall regions.
“We have had such success with canola over the past decade, so the crop has been pushed into those heavier soils in the more marginal rainfall areas, and paddock and soil type selection have not been as strict as perhaps they should have been,” he says.
“2017 highlighted the fragility of the crop in the more marginal areas.”
Reducing resistance
Mr Lamond says another concern looking forward is the lack of variability in varieties planted in WA.
According to the WA DPIRD/GRDC 2018 Canola Variety Guide for WA, almost 40 per cent of all plantings in 2016 were the open-pollinated, triazine-tolerant ATR-Bonito variety.
“This is a high-yielding, short-season variety that is well suited to large areas of WA’s south-eastern regions,” he says.
“Growers should be aware that the blackleg resistance rating for ATR-Bonito has been reclassified to moderately susceptible for the 2018 season. Therefore, alternating varieties, using seed dressings and a good overall farm rotation are all required to avoid blackleg becoming a major issue again.”
Early vigour
Mr Lamond says growers in WA’s northern wheatbelt are favouring hybrid canola varieties for their early vigour as well as for weed control. “In the lower-rainfall regions, quick establishment is critical to the crop’s success, so hybrids are now grown for this early vigour. In the north it is critical for the crop to establish quickly on limited moisture, so these hybrids are proving very suitable in these lower-rainfall zones,” he says.
Research findings
The GRDC-funded WA Tactical Break Crop Agronomy Project has involved 153 trials since 2013. Some of the findings from these trials include:
* best economic plant density for hybrid and open-pollinated varieties; at about 20 plants/m2 for both RR and TT hybrids and 30 plants/m2 for TT OP types
* likely yield from low density/poorly established crops. For example, hybrid types achieving 80 per cent of optimum density yield at only 7 plants/m2 and open pollinated at 15 plants/m2
* delayed nitrogen application to up to eight weeks post-emergence is unlikely to result in large yield or oil penalties in the low-rainfall area, enabling growers to play the season
* wider row spacings up to 50cm being suitable for the northern WA regions and
* the yield benefits of early sowing in different WA environments, yield gains of 40kg/ha/day when sowing in mid-April compared to late April in the northern region.
Mr Harries believes the findings played a big part in helping growers navigate the tough 2017 season. “In particular, we were able to advise against spraying-out low-density crops because our trial results showed that even with 10 plants per square metre, canola would still achieve a high proportion of its yield potential,” he says.
Also, the findings on the later application of nitrogen allowed growers to play the season more than they would have been able to five years ago. “This is all part of the evolving research and agronomy behind growing canola in Australia,” he says.
Snapshot
Growers: David and Steve Knipe
Location: Northam, Western Australia
Farm size: 5000 hectares
Enterprises: cropping and livestock (sheep)
Grains: barley, wheat, canola, export hay
Average annual rainfall: 400 millimetres
Soil types: gravels, river loams, heavy red and grey clays
Soil pH: 4.6
Successful plan took time
Northam, WA, grain grower David Knipe has been growing canola for the past decade, but says he has only managed to get the system right in recent years.
In 2018, David, who farms with his brother Steve, will drop his plantings to just 400 hectares – the smallest area of canola he has sown for some years – but he says the highly profitable oilseed will always be part of his rotation.
After trying different varieties over several years, and testing different fertiliser methods and compounds, David now has a well-established agronomy plan for his canola and is consistently achieving yields of about 2.4 tonnes per hectare.
The Knipes use 80 litres/ha of liquid nitrogen at emergence and another 20 litres/ha at eight weeks post-emergence. “We then put on another 50 litres at bulking stage,” David says.
Liquid fertilisers, he says, give far greater bang for his buck than anything granular. “Granular is cheaper but the plant appears more responsive to the liquid application. Liquid is also easier to store, easier to handle and is only a phone call away if we need to increase our application rates.”
Since the canola plant has such a large leaf, David says his main agronomy role is to keep the leaf greener, for longer, by applying fertiliser and reducing any stresses on the plant.
“A larger, greener leaf will mean the plant has greater vigour, thereby producing more seed pods.”
So, regardless of the year and despite the expense, he applies Prosaro® 420 SC foliar fungicide (prothioconazole and tebucanazole) to a large percentage of his canola crops. “I am a big believer in Prosaro®; it is a must if you grow canola in higher-rainfall regions,” he says.
“Last year was a tough start and the establishment of our canola crops was not flash,” he says. “So we took a gamble and sprayed our worst-looking crop with Prosaro® and it yielded much better than initially anticipated.”
Likewise, in years when they have had good early crop establishment and high rainfall, investment in fungicides has given the crops a big yield kick.
David also says being flexible in planning crop rotations is important to allow his business to take advantage of higher prices or to avoid seasonal challenges.
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