Western Canadian researchers and canola growers are building a body of evidence and experience that will help those who want to try straight combining canola. This article describes practices that can reduce the risk.

What we know about straight combining canola

By Jay Whetter

Published on 1 September, 2017

The key argument in favour of straight combining canola is the savings in time, labour and possibly machinery. On a farm with limited labour available at harvest, not having to swath canola can free up a lot of time and labour for combining. If farms decide to straight combine all canola, selling the swather may be an option.

The major benefit for swathing over straight combining, and this is a big one for many growers, is harvest timing. Standing canola can take longer to be harvest-ready. When it is ready, growers historically had a fairly narrow window to get the job done before shattering losses become excessive. Shatter-tolerant varieties have greatly reduced this risk, but harvest-readiness can still take longer for standing crop.

Another potential downside to straight combining is that when seeds and pods are ready, stems may be somewhat tough, making the combine work harder. Uneven crop and green weeds can also slow the harvest process. Pre-harvest sprays will dry down biomass to reduce or eliminate this factor.

Even with improvements in genetics and the option to use a dry-down spray, growers may still experience more flexibility with harvest timing when they swath canola.

Studies suggest that, on average, late-swathed and straight combined canola will yield about the same. The key is swath timing. An early-swathed canola crop has shown to be the lowest yielding of all treatments. Seed quality seems to be the same for both.

Risk factors for straight combined canola

Variety. Studies at Indian Head Agricultural Research Farm (IHARF) found that any variety can be straight combined successfully under low risk conditions. A well-knit crop with good pod integrity, low winds and timely harvest make for lower risk. However, when IHARF added varieties with pod-shatter tolerance in later years of the study, these varieties maintained their yield in a broader range of circumstances, especially if harvest is delayed.

Field choice. Flatter fields tend to have more even maturity. On rolling hills, hill tops may be prone to shatter losses and pod drop while waiting for the rest of the field to reach harvest readiness.

Stand establishment. An early-established and uniform crop with sufficient plants to narrow the range of seed maturity at harvest and to provide knitting together of mature plants will help improve harvest timing and harvestability of a standing canola crop.

Disease. Diseased plants dry down earlier and can make for uneven maturity. They also tend to lodge more. Diseased pods are more likely to shatter or drop prematurely. Limiting disease can improve harvest results for straight combining and swathing.

Weeds. Fields with a lot of late-season weeds should get a pre-harvest herbicide or be swathed.

Pre-harvest spray. Canola fields that mature early in the harvest window, are weed-free and have a good uniform stand may not need a pre-harvest spray to help with straight combining. The Prairie Agricultural Machinery Institute (PAMI) ran a trial of pre-harvest aids in 2016, comparing three treatments – Reglone, a Heat/glyphosate tank mix and natural ripening – against swathed checks. The study showed no statistical difference in yield for the four treatments, but treatments did influence harvest timing and combine efficiency. Reglone-treated plots were ready the same day as swathed treatments. Heat/glyphosate treated plots were harvested three weeks after application (partly due to a rain delay). Naturally ripened plots were ready at the same time as the Heat/glyphosate treatments. For the naturally-ripened canola, high green matter in the stand made harvest difficult. The PAMI report concluded: “Straight cut treatments with harvest aids had a higher cost of production, but the benefits of timeliness or ease of harvest may provide sufficient benefit to warrant this cost for certain operations.”

Combine header. Various studies have looked at headers. PAMI just finished a three-year study comparing rigid auger, draper and extended-knife headers. It concluded that all headers did the job within acceptable limits, but the extendable knife (PAMI used New Holland’s Varifeed in its study) did have lower losses, in general. Other studies came to similar conclusions about extendable-knife headers.

Harvest timing. The general recommendation is to straight combine canola as soon as possible after the seed falls below two per cent green content and is dry enough to store. Delays can increase shattering losses for varieties without shatter tolerance.

Lodging. Some lodging can be beneficial for straight combining canola. A slight lean tends to knit together plants to so they don’t move as freely in the wind. Heavily lodged crop, especially if lodged in all directions, might be a better candidate for swathing.

Weather. Weather factors that influence the harvest decision include:

Wind. Mature crop whipping in the wind can increase shatter losses. While swaths can also roll in the wind, the risk is probably higher with standing crop.

Hail. Hailed canola fields often grow back at various stages. While straight combining works best for an even-maturity crop, leaving a hailed crop standing for straight combining may allow more of the later pods
to mature and contribute to yield. Desiccation may
be required.

Fall rain or snow. Standing crop is often ready to combine sooner after these events, but heavy snow can push down standing crop, making it difficult to pick up.

Frost. Frost provides some natural desiccation that may help soften weeds and green stems for straight combining. Harvest may need to occur shortly after a frost.

Storage. In cases where straight combining results in higher levels of green dockage (either from crop material or weeds), this would increase the storage risk — as high moisture dockage could be a start-point for spoilage.

Want to share your experiences – good and bad – with straight combining canola? Email the editor, Jay Whetter, at whetterj@canolacouncil.org

Kevin Serfas | Turin, Alberta

Do you straight combine canola?
No, not yet. With the winds we get in southern Alberta, straight combining canola was not an option for us before the evolution of pod-shatter resistant (P) varieties. Last year, we grew an InVigor pod-shatter resistant variety on two fields but didn’t straight cut it. It allowed me to see what the trait is like. We switched half of our acres to pod-shatter resistant varieties this year, and we might try straight cutting a bit of it. Even if we swath it, timing isn’t as critical. Agronomically, the P varieties are lower performing than non-P varieties, but our P fields last year yielded about 7 bu./ac. higher than non-P. I think it was because they didn’t have any top-of-swath shattering.

Describe your land. Does this make a difference to straight combining success?
We have a little bit of everything. In fields with a lot of variability in topography, I don’t think there’d be a situation where we could straight cut without some desiccation or Roundup. We notice the differences when straight cutting barley and wheat, so they could be worse with canola.

What do you think would be the most important steps for success with straight combining canola?
I expect steps for success, besides the pod-shatter resistant varieties, would be an evenly dried-down crop and a decent header. I think we have one in our John Deere drapers.

What is the biggest risk?
After seeing pod-shatter resistance, I’m not sure wind would be the biggest issue anymore. I’m not sure what the biggest risk will be now that I have faith in the technology.

Would you expect a difference in overall profitability between straight combining and swathing?
Seed with the pod-shatter resistance trait is about $10 per acre more. Whether you swath or straight combine the variety, you’re going to get at least a one-bushel benefit from reduced harvest losses. We have a sprayer already and I’m not going to sell the swather, so whether we spray or swath canola, it will not change our equipment investment.

Anything else you’d like to add?
At the end of the day, a big part of the decision is personal preference, geography and how your farm is set up. We have lots of tools available to us as farmers. We use the ones that fit best with our operations.

Dennis Reimer | Hudson Bay, Saskatchewan

Do you straight combine canola?
Yes. It saves us the extra pass of swathing. We suspected that swathing was causing us yield loss because we had a lot of late, immature seeds in the swath. Waiting to straight combine gave them time to mature. In the earlier years, we confirmed a 3 bu./ac. advantage with weigh wagon comparisons. It has been as low as 1 bu./ac., but in that case the swather had GPS guidance but the combine didn’t. So the combine was running fuller with the swaths, which may have meant lower harvest losses.

What percentage of your canola do you straight combine?
100 per cent

How many years have you been doing it?
We started in 1997. My son Darryl encouraged us to try 40 acres.

Describe your land. Does this make a difference to straight combining success?
Our land is reasonably flat with peaty pockets. Flat land does provide an advantage. Knolls are often riper and more subject to wind loss.

What are the most important steps for success with straight combining?
In our experience, not seeding canola too early is important. We want the crop to mature in September so we are not combining in hot weather. In cooler conditions, the risk of shelling diminishes.

Under what circumstances would you decide to swath a crop instead of straight combine?
If the cereals were all combined and the canola wasn’t ready, I’d probably wish we had some swathed canola to combine.

What varieties have you straight cut?
We have used InVigor varieties from the beginning. When the pod-shatter P varieties came along, that’s when we finally decided to sell the swather.

What type of combine header do you use?
MacDon draper headers with pea augers.

Do you use a pre-harvest spray?
Not usually. We tried it once.

What is the biggest risk?
Last year we had 350 acres that got snowed on and never got harvested. We decided to just harrow it and burn it this spring. As a result, we got 95 per cent of this year’s crop seeded. A lot of swathed crop was left out all winter as well, and while the swaths could be salvaged, some of those farmers fiddling to harvest that canola only got 50 per cent of this year’s
crop seeded.

In 2011, the year of wind, we had one field that was 50 per cent shelled out across about half the field. Pods were actually knocked off the stem intact – that’s how windy it was. But over the rest of our 1,200 acres of canola, I got out of the combine a lot to check on shattering, and it seemed to be no more than 10 per cent loss. Swathed crops were also blown around badly that year. Some guys were lucky to harvest 50 per cent of the yield with swathed crops. So both were at risk.

That was the year that really told me straight combining was not as risky as people thought. However, if the wind had come a week later, it would have made the situation a lot worse for standing canola. The swathed crop would have been harvested and the standing crop would have been that much riper and at even greater risk. Swathed canola can usually be harvested earlier – that’s true – but for us, by the time our cereals are harvested, the standing canola is ready. And if swathed crop is still out by late September, it can take a lot longer than standing canola to dry down and be harvest-ready.

What difference in overall profitability is there between straight combining and swathing?
We don’t have to own a $100,000 swather or need to hire a man to run the swather while cereals are ready to be combined. The extra yield from straight combining is always profit.

Describe the biggest mistake/disaster you’ve had with straight combining?
I can’t say we’ve made any major mistakes. The year of wind was bad but it was no worse than with swathed canola. Last year, my son-in-law tried straight combining canola for the first time. It was a specialty variety and he had excessive shelling in the standing crop, but his swathed crops were fine. He had an immediate disaster. We never had that negative first experience.

Anything else you’d like to add?
You will always combine standing canola slower than picking up a swath. We combine at two to 3.5 mph whereas a combine can go four mph with swaths. But for a $30 per acre difference in yield, we feel it’s worth the time.