Canadian growers seek step-change agronomy
GroundCover™ Issue: 110 | Author: Sarah Clarry
In Alberta, Canada, a four-month growing season means time is scarce; however, according to grower and agronomist Steve Larocque, “scarcity drives innovation.”
At the GRDC Update in Temora, New South Wales, an audience member asked Steve Larocque where the best place in the world was to be a grain farmer.
“Three Hills, Alberta, Canada,” Steve said, without hesitating.
It would be easy to view this as a parochial answer from a proud Canadian grower and agronomist. But Mr Larocque is a Nuffield Scholar who has visited five continents, studying the ways in which others deal with the obstacles they face growing grain. He knows from experience that Canadian growers have great conditions in which to grow grain, even if harvest has to be rushed to avoid the snow.
He was also asked which countries, of all the places he has visited, are doing well.
“Countries that don’t receive government support – New Zealand, Australia, Argentina, Brazil. They have to be innovative to be competitive. Scarcity drives innovation,” Mr Larocque said.
He also noted that such innovation soon becomes global: “Australian growers are water limited. Controlled traffic was something I took out of Australia to improve water use efficiency (WUE) back at home.”
So why is Three Hills, Alberta, the best place in the world to be a grain grower?
“We have a forgiving climate, great soils … and government support,” he said. “We’re very comfy in Canada. There’s not a lot of incentive to do things differently.”
However, Mr Larocque does want to do things differently. Even coming off a record season in Canada in 2013, he sees a world of difference between the yields Canadian growers are realising now and the yields they could be getting.
His presentation at the GRDC Updates outlined how crops do not reach their maximum yield potential – which he estimates could be up to 70 per cent higher – due to multiple stress factors (Figure 1). He split these stresses into abiotic and biotic.
Abiotic stresses include:
- mechanical stress (such as wind);
- agricultural chemicals;
- soil type;
- gases; and
Biotic stresses include:
- viruses; and
He believes agronomy, more than genetics or any other factor, is the key to unlocking some of that lost potential yield.
Such improvements include controlled-traffic farming (CTF), nitrogen use efficiency, managing soil and root temperatures, and using sensor technology such as the GreenSeeker® for real-time mapping and variable-rate nitrogen application.
Steve first encountered CTF during a trip to Australia in 2009 when he visited Robert Ruwoldt at Horsham, Victoria.
He found himself back in Australia another three times to visit more than 30 CTF farms from Dalby, Queensland, to Esperance, Western Australia. Impressed by the possibilities of managing variable rainfall patterns through improved soil structure and WUE, he implemented the system on his return home.
He now runs a nine-metre system on 3m axle spacings with Trimble RTK two-centimetre guidance. His equipment includes a 9m Concord seeder, an 18m Spray Coupe boomsprayer, an 18m FAST 8100 side dress nitrogen toolbar and a John Deere 9750 header with a 9m front.
He has also introduced CTF to many of his clients in western Canada. After four years of proving the CTF system on his farm, he has now given the green light to clients to start making the transition.
“I found no production risk with CTF and we can manage financial risk by converting equipment over time. CTF offers a way to improve yields with very little rain or excessive rain, which is what we tend to get in western Canada.”
Nitrogen Use Efficiency
With just 110 days from sowing to harvest (Table 1), Canadian growers have a tight growing-season schedule. The usual grower practice is to apply all nitrogen up-front at sowing. However, the typical nitrogen uptake by a wheat crop is:
- 30 per cent by GS31;
- 40 per cent between GS31 and GS39; and
- 30 per cent from GS39 to GS87.
To meet the growing plants’ needs, Mr Larocque uses a split application of 60 per cent up to flag leaf (GS39) and the remaining 40 per cent after flag leaf early ear emergence.
There is a 20-day window from GS30 to flowering where growers can apply nitrogen. GS30 coincides with the region’s longest daylight hours (18 hours), warmest temperatures and highest soil-moisture content. This combination makes for rapid transitions from one growth stage to the next.
Growers need a form of nitrogen that is immediately available. Mr Larocque uses a FAST 8100 side dress toolbar to coulter in liquid nitrogen between the rows to a depth of 75 millimetres, where roots have immediate access.
Initial trials have shown a 15 per cent reduction in applied nitrogen (N) is possible without a yield penalty. Trials in 2013 also showed a 45 per cent yield increase from an additional 60 kilograms N/hectare at flag leaf when N was limiting; although 2013 was a year with optimal rainfall and cooler conditions during grain fill.
The next step for Mr Larocque is to combine GreenSeeker® technology with the side dress nitrogen toolbar to solve the last piece of the puzzle: “How much nitrogen do we need and where do we need it?”
Trials in western Canada have shown a six to 15 per cent reduction in nitrogen use with no yield penalty when top dressing liquid nitrogen in wheat and canola using GreenSeeker® technology.
“Marrying the side dress toolbar with a GreenSeeker® could add up to some serious nitrogen use efficiency,” Mr Larocque said.
Root heat index
Mr Larocque’s research has also found that high soil temperatures during grain fill can have a large bearing on yield.
Heat stress during grain fill reduces kernel weight by three per cent for every 1°C above 20°C, up to 60 per cent when the root temperature exceeds 30°C.
He says the soil temperature has a much greater impact on biomass and yield than ambient temperature or soil moisture.
He recommends the following measures to keep soil temperatures down:
- stubble retention;
- row spacing;
- plant density;
- proper residue distribution;
- inter-row sowing;
- tall stubbles; and
- reducing compaction.
In addition to the 12,140ha he manages as part of his consultancy, Mr Larocque distributes his agronomic advice to clients and subscribers via a weekly newsletter, Beyond Agronomy News.
From his most recent trip to Australia, Mr Larocque said he is taking back three key lessons.
First, a greater understanding of moisture use efficiency at depth, where subsoil moisture is three times more efficient at producing grain than surface moisture.
Second, that deep banding manure is an effective way to increase yields by 60 to 100 per cent in sodic soils. Finally, and perhaps not surprisingly, modelling around WUE.
“Although not perfect, the French–Schultz moisture use efficiency model to predict wheat yield based on rainfall and evaporation has piqued my interest to see what we can produce with one millimetre of rain compared with the Aussies,” he said.
GRDC Project Code ORM00005
Region North, Overseas, South, West