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The straight goods on straight cutting crops

Straight cutting has the potential to make canola harvest much more efficient, so we ask one of the West’s top researchers about the state of the art

man harvesting a canola swath

Just 20 years ago, virtually every acre of Western Canada was swathed before it ever saw a combine. But then a few things started to fall into place — mainly cheaper off-patent glyphosate — that meant farmers could stop the growth of their crops and get them to dry them down more quickly and uniformly. Soon the sight of straight combining cereal crops became more and more common, to the point where today, it has taken over a significant chunk of the harvest.

But not in canola, the region’s most economically significant crop. In canola, the plant’s design works against straight cutting. In particular, the pods can be easily shattered and their seeds spilled out, making growers nervous about adopting any system that would see plants left to mature and dry while standing.

Some growers have seen success with the system. A 2009 survey by the Canola Council of Canada showed 14.6 per cent of growers were straight combining at least some of their canola, and 13.8 per cent of those surveyed said they’d like to do more. Even so, recent estimates suggest those numbers have moved only slightly, with most surveys saying the number is still below 15 per cent of harvested acres.

But nobody seems to have given up on the system completely. The benefits of further streamlining operations during a busy and stressful part of the season simply make too much operational and economic sense. So the research continues.

Some of the most recent research is actually quite promising, including a University of Saskatchewan study that found canola harvest losses were approximately 10 per cent, regardless of whether the crop was swathed or straight cut, suggesting that swathing has risks, but those risks are simply different, not greater than, the risks associated with swathing canola.

Country Guide was fortunate enough to get one of the region’s leading straight-cut canola researchers to take a break from harvesting his research trials at the Indian Head Agricultural Research Foundation site, just east of Regina on the Trans-Canada Highway. Chris Holzapfel, the organization’s research manager, says over time the two systems can provide similar results, but there is the potential for losses under either.

“If you look at the big picture, both systems work well, and I would expect similar yields between the two over time,” Holzapfel said. “Swathing tended to be a bit better in years where harvest was delayed or frequent rains or heavy winds were encountered during the most vulnerable crop stage, when it’s ready to combine. In contrast, straight combining sometimes produced higher yields. I can only really attribute this to larger seed size, which is also a function of timing of swathing.”

When canola is swathed at the optimal time — no earlier than about 60 per cent seed colour change — the seed size result can actually be similar. However, Holzapfel says there’s little doubt that’s a very narrow window for covering a lot of ground in a hurry, meaning the actual results out in the field are frequently less than optimal.

“It can be very difficult for growers to cover all of their acres at the optimal time,” Holzapfel agreed. This leads to perhaps his most important recommendation for growers pondering trying out straight cutting canola. Begin incrementally, Holzapfel advises. Don’t ratchet your risks by shifting too fast.

“Growers need to find the balance between swathing and straight combining that works for them,” Holzapfel said. “If they’re new to straight combining, I always recommend starting with limited acres first to gain confidence and experience.”

Some of the larger growers with the most experience straight combining seem to have found such a balance, Holzapfel said. Taking great care to maximize seed size by not starting too early, they swath where they can. When the crop gets too advanced, they then stop and leave their remaining canola for straight cut.

Most growers use either glyphosate or a desiccant to halt crop growth and begin the drying-down process. Holzapfel stresses that it’s important to remember glyphosate is not a desiccant, and it obviously will only work on Liberty Link and Clearfield canola, not Roundup Ready varieties.

A key area of risk is harvest timing, something Holzapfel has examined in his research. They first combined as near as possible to optimal timing, then delayed harvest two to four weeks, measuring pod shatter under each scenario. Holzapfel says “not surprisingly” these tests showed higher losses with delayed harvest.

“If you can be right on top of it, losses will almost always be minor, but when weather gets bad and things get delayed, the risk increases,” Holzapfel said.

All this has led to a search for better techniques and technology to minimize these risks. One is an array of commercial pod sealants that are applied to the crop at roughly the 40 per cent colour change stage, when the pods are still pliable. The coatings will prevent shattering during combining, but so far the results have been inconclusive, Holzapfel said. When losses are low due to a good harvest, no benefit is seen, and when it’s a real train wreck, nothing seems to help.

“We seemed to get the best results when yield losses due to shattering occurred, but were not too extreme,” Holzapfel said. “With a delayed harvest, pod drop accounts for a large percentage of total seed losses and pod sealants are not designed to protect against pod drop, which may be another reason for the inconsistent results.”

There’s also a lot of interest in better harvesting equipment, something Holzapfel says research organizations like Wheatland Conservation Area have been tackling. “I do believe that having the right equipment for the job will be an important factor for success.”

One promising technology is a European header extension. There are several brands, all with the same shared design premise, Holzapfel said.

“It positions the knife farther ahead, so that the canola is cut and above the table before coming into contact with the reel and being moved into the throat of the combine,” Holzapfel said.

Several of the newest North American header designs allow operators to adjust the knife position on the go and may offer many of the same benefits.

“They may be well-suited to straight combining canola but still useful for cereal and pulse crops, which was one of the criticisms of the older extensions — that they were only useful for canola,” Holzapfel said.

European research clearly shows a reduction in shattering losses when the knife is positioned as far ahead as possible. IHARF is partnering on a project with other organizations to evaluate different header types, but the 2014 season is the first harvest, so no results are available yet.

A final research area involves looking at varietal differences, but Holzapfel says it’s not as cut and dried as saying which can or cannot be straight combined. “The reality is we have generally been able to successfully straight combine all the cultivars successfully, and the environment and timing of harvest operations are going to be the main factors.”

Holzapfel also noted that new hybrids, such as L140P and 45H32, promise improved tolerance to shattering and pod drop, and may be a significant improvement. However, 2013 was the first season they looked at these new offerings, and it happened to be a season with very low overall shattering pressure, meaning most of the cultivars under examination fared well.

Said Holzapfel: “Overall I think good agronomy, proper timing of operations and perhaps a bit of luck play a bigger role in determining the overall extent of losses in any given year than genetic differences.”

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