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Take another look at straight-combining canola

Saskatchewan researchers examine straight-combining canola and make some recommendations to reduce losses for those willing to try it


At a summer research field day in Swift Current last July, quite a few farmers raised their hands when researcher Chris Holzapfel asked how many had experience with straight-combining canola. Holzapfel looked a little surprised, until he remembered that many farmers in southwest Saskatchewan are new to canola and probably don’t have a swather handy.

But even if you have a swather on deck, you might want to think about straight-combining some of the canola on your farm.

In 2011 and 2012, Holzapfel of the Indian Head Agricultural Research Foundation (IHARF), with the help of several sponsors including SaskCanola and the Manitoba Canola Growers, led a team of researchers looking at straight-combining canola.

In two years of trials in four different locations across Saskatchewan, swathing was better in some years and locations, while in some situations straight-combining led to less shattering, Holzapfel told farmers attending Canola Day on Nov. 5 in Weyburn, Sask. Results depended primarily on weather and timing, he said.

If you’re in a situation where straight-combining makes sense, there are things you can do to decrease potential losses. However, there isn’t much you can do about wind. Indian Head had as much wind as anywhere else in 2012. When researchers went out to measure losses about a month after straight-combining, they found a 62 per cent yield loss.

Part of this loss may have been caused by sclerotinia, but wind was a big issue. On Aug. 25, winds at the Indian Head station were 80 km per hour. As Holzapfel says, that’s “difficult to plan for.” On 32 of the 40 days before harvest, wind speeds were greater than 31 km per hour.

If you’re going to try straight-cutting your canola, here are four factors to think about first.

1. Pod Sealants

Pod sealants have been available in Western Canada since 2008. These products are designed to reduce shattering losses in any pod-forming plant. Holzapfel and his team tried three brands: Pod Ceal DC, pod-Stik and Desikote Max.

While there were a few cases where pod sealants led to lower shattering losses, after measuring seed left on the ground post-harvest, Holzapfel told farmers in Weyburn, “In most cases — seven out of eight cases —we had no significant benefits from using the pod sealant.”

Holzapfel estimates the cost of applying pod sealant is likely equivalent to the cost of swathing. Aerial application would do less damage, but would also make pod sealant even more expensive.

Holzapfel says, “When we looked at the big picture, we just didn’t see a return on investment.”

2. Glyphosate

When it came to using glyphosate pre-harvest, Holzapfel found no significant impact on the yield that made it into the combine. However, he said using glyphosate was still “a nice way to get rid of some of that variability you always see.” Glyphosate also brings the benefit of weed control.

3. Header choice

At the Swift Current site, Holzapfel measured seed loss at harvest using four different types of headers: rigid, draper and stripper headers, as well as BISO header extensions. (BISO header extensions are imported from Europe, where they’ve been designed specifically for use in rapeseed. They can be attached to existing headers, but do not fit on all types. They are currently available in widths only up to 30 feet.)

Holzapfel said they “definitely got the best gains with the BISO header extension.” The next best option was the draper header, with a rigid header coming third.

4. Variety choice

Although, as Holzapfel says, “Polish canola is a little less prone to shattering,” to make his research more relevant, he looked at 12 different high-yielding Argentine hybrids. In 2011, trials were started in Indian Head, Scott and Swift Current to look at the importance of varieties.

While his research isn’t fully compiled yet, Holzapfel is willing to make some preliminary comments. Overall, the research found that LibertyLink varieties produced the least shattering, followed by Clearfield seed, with Roundup Ready taking third place.

Holzapfel saw a lot of variability, but says, “One variety in particular came out to be much better.” Bayer’s Invigor 5440 was the best performer of the 12 varieties.

“In most locations, especially where we had pretty high losses, it was doing a little bit better.” Holzapfel says, “Invigors do hold up fairly well overall. But that’s not always the case.”

This information was kind of a by-product of the original study. “Our real intent was to evaluate the pod sealants,” says Holzapfel, “but this was something that came out.”

But as he reminded the Weyburn audience, variety choice can’t fix everything. “If you take anything home from this, none of these varieties are shatter proof,” Holzapfel says.

Swathing pros

Swathing has many benefits.

1. Timing: When swathing, “you knock it down and it’s ready when you are,” says Holzapfel. This is a way to even out maturity, and desiccate green weeds. Once your crop is swathed, you can be more flexible about harvest dates, working around other crops’ maturity as necessary.

2. Maturity: Swathing can even out maturity (especially important in an uneven field), and can desiccate green weeds.

3. Avoid shattering loss: This is the biggest factor. Holzapfel says, “it comes down to risk.” One year of bad loss may have paid for the purchase of a swather, and maybe even hiring someone to run it.

Straight-combining pros

As Holzapfel has found, straight-combining isn’t all downside.

1. Timing: “There is a fairly narrow window of optimal timing for swathing,” Holpazel says. “If you’ve got a lot of acres to get over, limited manpower and equipment, and other crops to deal with,” you may want to have two options. If you can’t get to every field at just the right time to swath, maybe it makes sense to leave some canola standing, and plan to get the timing right with your combine.

2. Costs: Of course, straight-combining will save you the costs of swathing, and the labour you need to have on hand to get it done at the right time.

3. Reduced risk under some conditions: In cases where you have a lodged crop or sparse stubble, you may not have much of a stand to hold your swath in place, incrasing your chance of blowing.

4. Seed quality: Leaving your crop standing all the way to maturity results in larger seeds, and higher oil content. Overall, he found a six per cent increase in seed size — an increase in weight from 3.2 to 3.4 grams per 1,000 seeds. This balanced out a roughly six per cent increase in shattering losses.

This isn’t an economic factor to consider now — as Holzapfel says, “farmers don’t get paid for oil” — but some day, processors may reward farmers financially for providing seed with higher oil content.

Because this study used small plots, straight-combining is at a slight disadvantage. There are more edges per acre in smaller fields, and plants on the edges of a field have less protection from wind and weather.

Overall, Holzapfel says, “Don’t be afraid to try straight-combining.” But remember, he says, “there are some risks.” †

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