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The mechanics of straight cutting canola

It’s a question more canola growers ask with every harvest. 
Do I go straight cut or swath?

Frankly, it’s not always easy to make harvest decisions because a lot can depend on variables beyond a grower’s control. But of the factors that a grower can control, the research until now has been weighted fairly heavily toward the crop itself — varietal suitability, optimal harvest timing and so on.

What about harvest equipment? “We’ve been raising the flag on that for a number of years,” says Nathan Gregg, a project manager in applied agricultural services for the Prairie Agricultural Machinery Institute (PAMI) in Humboldt, Sask. One of the main concerns with straight cutting is shatter loss, and PAMI wanted to study the role equipment plays in that loss.

Then, in 2014, a consortium of funders (see “Better together” below), including Western Grains Research Foundation came together to find out what kind of combine headers work best in a straight-cut system. “We are the principal investigators in a collaborative research team, and 2014 was the first year of a three-year study,” says Gregg.

What’s interesting about all of this is that while the Canadian canola producers are tying themselves in knots about straight cutting, it’s the dominant canola harvest system in Europe. They even have combine headers specifically designed for the job. Couldn’t we just use those?

Perhaps, says Gregg. But the fact is that growing conditions in Western Canada, not to mention our far shorter harvest window, may not make this a practical solution for all growers in all years. “Our purpose with this research is, if there is going to be a progression to straight cutting, what can a farmer do — because not everyone can afford to go and buy a specialized header,” says Gregg. “We want to find out what adjustments farmers can make to achieve successful straight cutting.”

In the first year of the study, the main goal was to establish some benchmarks for shatter losses using four different equipment configurations (known as treatments) on two different canola varieties. Three of the four treatments were for straight cutting, while the fourth was standard swathing to act as a check. For straight cutting, the study used a draper header, rigid auger header and a European-style header, which has a hydraulically extendable cutter bar that allows the knife to be placed beneath the reel instead of behind it.

All four treatments were used on a standard canola hybrid (InVigor L130) and a shatter-resistant hybrid (InVigor L140P) on two field sites (Indian Head and Swift Current) set up in a replicated split block design (each block is split in half, with one variety on either side, and each half of the block receives all four treatments; treatments have four replicates, or blocks, in the field). “We used field-scale machinery with 35-foot headers, so these are not your four-foot plots,” says Gregg.

“We targeted optimal harvest dates,” says Gregg. “So we swathed the check at the optimal time according to industry guidelines and that became the start date of our trial.

Now, canola seeds are pretty small and bouncy, so collecting shatter losses was no easy task, and researchers aimed to look at losses prior to, as well as during, straight cutting.

“We wanted to get a sense of losses from just leaving the canola standing, so we put collection pans out in the standing crop on the day we swathed the check,” he says. “We put 40 or 50 trays across the whole field to get a sense of overall loss for each variety.”

Shatter loss collection got even more intense once straight cutting began. “We strategically placed the pans between the rows so that any losses from the reel, knife — any part of the header — would be collected,” he says. “We put 10 pans across the width of the header at four locations within each treatment.” The split block design means that there were 960 collection pans at each field site, for a total of 1,920 shatter loss samples to analyze — in addition to the pre-harvest collections.

Other than the headers, everything stayed the same during harvest, from driving speed to reel, knife and threshing speeds. “We didn’t want to throw in confounding or confusing data,” says Gregg. It makes sense: for example, if they had used a faster reel speed on the draper header and wound up with higher shatter losses, how could they be sure those losses were attributable to the header and not the reel speed?

“Next year, we’ll be able to play a bit with other factors,” he says. Header height and angle, reel speed and height, knife speed, crop dividers/vertical side-knife, reel position, auger/draper speed — these are but a few of the variables that could be looked at in coming years. “We needed a little field time to narrow the scope and see which ones matter.”

Gregg and the PAMI team have cleaned and weighed this year’s shatter loss samples, and are now in the midst of data analysis. Still, he says there are a few anecdotal observations to share. “I can say fairly definitively that the shatter-resistant variety did outyield the non-resistant variety,” he says. “I don’t know by how much yet, or if it’s a statistically significant difference, but at one location where we had a significant wind event, you could actually see that in the field.”

As for the header configurations: “All treatments worked well,” says Gregg. “You couldn’t pick one out and say that it just didn’t work at all. Going in, we thought we might see more loss at the crop divider, and based on the shatter trays, there seemed to be more loss at the edges of the headers. How much of that is attributable to the vertical knife at the crop divider, we don’t know yet.”

The next two years of the project aim to find that out, and more. “The reason we’re doing this is because farmers are asking questions,” says Gregg. “Some have tried and failed, others have had great successes. People are asking — how do you actually do this?”

And how do they cost it, too? “There may be an economic advantage to not doing that swath operation,” Gregg says. “But we wanted to put a cost to straight cutting — because you know you’re going to have some costs. We want to be able to say, if you have a rigid header, that X is the economic impacts to using it to straight cut your canola.

“I don’t think this is going to be a one-size-fits-all solution,” says Gregg, explaining that this research is not meant to come up with a “winner” in terms of a header design or modification that is the ideal for straight cutting in all conditions — that’s impossible.

“But hopefully, over the three years of the study, which is a minimum of six site years, we can see some trends over the diversity of conditions, and give farmers the full spectrum of possibilities so that they can make informed decisions about equipment for straight cutting canola.”

Better together

It is said that we are stronger when we work together, and nowhere is this more apparent than in the long list of participants in PAMI’s three-year project looking at canola straight-cut harvest systems.

Funding is being provided by:

  • Western Grains Research Foundation
  • Saskatchewan Ministry of Agriculture and the Canada-Saskatchewan Growing Forward 2 bilateral agreement, administered through the Saskatchewan Agriculture Development Fund
  • SaskCanola

Project Partners are:

  • Indian Head Agricultural Research Foundation
  • Wheatland Conservation Area Inc.
  • Harvest systems and statistician consultants

Project co-operators are:

  • Honey Bee Manufacturing
  • Case New Holland
  • Bayer Crop Science

Western Grains Research Foundation (WGRF) is a farmer-funded and -directed non-profit organization investing primarily in wheat and barley variety development for the benefit of western Canadian producers. Through investments of more than $57 million, WGRF has assisted in the development and release of more than 100 new wheat and barley varieties over the past decade and a half, many of which are today seeded to large portions of the cropland in Western Canada. WGRF also invests in research on other western Canadian crops through the endowment fund. In fact, since 1981 the WGRF endowment fund has supported a wealth of innovation across Western Canada, providing over $26 million in funding for more than 230 diverse research projects.

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