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The straight goods on straight cutting canola

Researchers are investigating factors affecting the success of straight cutting canola.


November 23, 2007
By Carolyn King

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The advantages of straight cutting compared to swathing of canola include lower fuel costs, saved time, reduced equipment wear and possibly higher yields. But straight cutting also has risks, especially the risk of increased yield losses due to seedpod shattering while the crop is standing. To help growers with their harvest decisions, a three year study is investigating factors affecting the success of straight cutting.

The study is testing the idea that canola crops with a higher yield potential are better candidates for straight cutting than crops with a lower yield potential. “As potential yield increases, the branches and pods intertwine with each other, knitting the canopy together, so in a high wind situation, the crop canopy will move as a whole,” explains Dr. Paul Watson of the Alberta Research Council. In contrast, when the canopy is thin, the plants can move independently from one another in the wind so the branches can slap against each other, greatly increasing the risk of the seedpods being shattered or knocked off.

Watson is working on this research with Dr. Neil Harker and Stewart Brandt, both from Agriculture and Agri-Food Canada. The Alberta Canola Producers Commission funds the project, which started in 2005. Field plots are located at Vegreville and Lacombe, Alberta, and Scott, Saskatchewan.

The researchers are comparing the effects of four factors on straight cutting yields and profits: low and high seeding rates (two and six pounds per acre), low and high fertility (zero and 120 pounds per acre of nitrogen), early and late timing of weed removal (three leaf stage and five leaf stage), and early and late harvest time (20 percent moisture and 10 percent moisture). High seeding rate, high fertility and early weed removal all contribute to a higher potential yield and a denser crop canopy. As well, the researchers have some swathed plots to make comparisons with straight cutting. For all plots, they are collecting data on yield, yield loss due to shatter and to ejection from the combine, crop density, canopy interlock and percentage of green seed.

Thus so far, the study’s results show straight cutting is a viable option, with some straight-cut treatments equal to or better than the best swath treatment at all locations. The results also show, “If you use all of the best farming practices – good fertility, good seed density and early weed removal – then the chances of being successful with straight cutting are increased,” notes Watson.

A related finding is that in poorly productive areas, growers must do more things right to make straight cutting work, while in highly productive areas, there is more room for mistakes. Watson explains, “So in a highly productive area like the Lacombe area, if you get even a little bit right, then the chance you’ll be successful with straight cutting are improved. In Vegreville, you have to have good fertility or else you can’t straight cut. And in Scott, you need both good fertility and good seed density to be successful.”

Watson concludes, “Straight cutting seems to work fairly well in most areas, but there is still some work to be done that will help to reassure farmers intending to straight cut that they’re
not going to lose all their yield before they can get it into the combines and the bins.”

Agronomist John Mayko with the Canola Council of Canada also sounds a note of caution: “Especially over the last five or six years with the need to cut costs, more and more growers have been looking at straight cutting. And many of them are trying it, having reasonable success, and are continuing with it. But growers need to make sure they have fields that are suitable candidates for straight cutting. Growers who go into it thinking, ‘I swathed last year. Now this year I’m selling my swather and I’m going to straight cut everything’ could end up with some disasters on their hands.”

One producer’s approach
Watson got the idea for the study from speaking to Wilson Lovell, who farms near Lacombe. Lovell has been successfully straight cutting canola for many years. He says, “I was anxious to get some research done because straight cutting really has worked well for us, and it’s nice to share things that work.” He is hoping that Watson’s study will find out why straight cutting works so well for him and what factors might affect its success for other farmers.

Lovell’s move to straight cutting came out of his attempts about 15 years ago to swath Polish canola later, in order to let the crop mature a little longer so the seeds could reach a larger size. He says, “Although the later swathing was helping, our swathing losses were also more noticeable. So we decided to try straight cutting a little bit. We didn’t straight cut the whole farm the first year. It was about a three year phase-in.”

He adds, “We just carried the later swathing to the next logical step because straight cutting is the ultimate on letting the crop mature.”

Lovell switched to Argentine varieties about 10 years ago. At the time, specialists recommended Polish varieties for straight cutting because those varieties were not as prone to shattering as the Argentines. So Lovell started swathing again, but gradually switched back to straight cutting as he found that straight cutting the Argentines worked well for him.

The savings on fuel, time and equipment wear from omitting swathing and the improved yields have made straight cutting the way to go for Lovell. “Our yields with straight cutting run from 10 to 35 percent better than with swathing, depending on how green the canola is when swathed. I know Paul’s research isn’t showing that big a yield advantage to straight cutting, but that’s what we’ve measured here with our yield monitors.”

Lovell emphasizes the importance of a dense crop canopy for successful straight cutting. “You want the canopy to mesh together and make a solid mat, preferably lean over at about 30 degrees,” he explains. He adds, “We’ve had wind that would roll swaths – our neighbours were out there trying to find their swaths. And I’ve crawled underneath the canopy and you do not see the shattering loss.”

Mayko says achieving the dense, slightly lodged canopies needed for straight cutting requires adequate moisture for the crop as well as appropriate production practices. “Moderate to heavy seeding rates are helpful because they tend to result in more main stems and less side branching, so the plants are more likely to lean or lodge later in the season. Growers should also look at fertilizing adequately. A crop that is well nourished is likely to have more weight in the top part of the canopy, in the pods, and more likely then to lean over. And a third factor might be to choose a variety with less lodging resistance.”

Lovell uses several, key management practices to increase success. He seeds early and uses a seeding rate between five and seven pounds per acre, and applies between 90 and 110 pounds per acre of nitrogen. Lovell takes weeds out early and often, so he really prefers Roundup Ready canola. He likes to do a pre-seed burnoff and then hit the weeds twice in-crop with a half litre of Roundup.”

He harvests right after the first frost. “Once the canola is mature, we look forward to the frost to dry it down. We’re drying down the green material – not green seeds – the little pieces of stems and everything that show up in the sample.”

All of Lovell’s bins have aeration systems as well as sensors to detect heat. Right after putting the canola in the bins, he turns the air on for a couple of days to cool the seeds. He stresses that growers must be very careful when storing straight-cut canola with green dockage in it. “Especially if you have air-tight bins, then you really need to watch it or you could have trouble with spoilage.”

Lovell recognizes that straight cutting can be risky when he leaves the crop standing for a long time, sometimes into October. “Don’t ever get hail the day before you want to combine!” he laughs.  Although Lovell has done some swathing in years when the canola was very late to mature, it has never worked to his advantage. “The last time we swathed was three years ago. Our canola was greener than grass and it was the 10th of September and we were sure it wouldn’t get ripe. So we swathed the greenest areas to get rid of some of the green seed count. But as it turned out, it didn’t freeze until October and the areas that we swathed yielded 30 percent less than the somewhat riper hills that we straight cut.”

He adds, “You really have to work with the mental aspect of straight cutting. When all your neighbours are out there swathing and you’re sitting on your deck watching your canola blow in the breeze, it takes getting used to. On the other hand, after your canola gets ripe and you happen to get rain, then you can go out and combine while your neighbour is sitting on his deck because his swaths are wet!”

Harvesting and storage tips when straight cutting
John Mayko outlines some harvesting and storage considerations for straight-cut canola:
Generally he recommends that growers straight cut as soon as possible after the canola reaches nine to 10 percent moisture, because the longer the crop is standing, the greater the likelihood of hail, wind or other factors affecting it.

Growers should ensure the sheet metal around the header mounts is in good condition to avoid losing seeds through cracks or holes.

Usually in straight-cut canola, the seeds and pods are quite dry, but the stems are tougher and moister than they would be in a swathed crop. Some growers apply a desiccant, like Reglone (diquat), or a harvest aid, like Roundup (glyphosate), to dry down the crop before straight cutting. If growers do not dry it down, then the combine might require more power to handle the tougher stems. On the plus side, however, those tough, wet stems do not get broken up as much when they go through the combine. With less fine material, it is easier for the combine to separate the seed from the straw. So, often the sample will have lower levels of dockage than a swathed sample.

Growers need to have bins with aeration to cool down the grain properly and keep it in condition. If they bin the crop at higher moistures, especially greater than nine or 10 percent and especially
if they are using bigger bins, they can have spoilage problems if the grain is not conditioned properly.