Straight-cut canola demands dry-down chemistry

Research and grower experience prove that straight cutting canola results in larger seeds, fewer green seeds, less dockage, better weed control, minor yield increases and zero risk of losing swaths in a big wind.

Straight cutting also offers a way for a grower to stay on schedule even as the farm expands.

It’s estimated that half of all canola acres will be straight cut by 2020. In a 2015 survey, three-quarters of growers expressed an interest in trying it.

But eliminating one field operation means adding another. Instead of swathing, it’s critical to make a herbicide application, according to Angela Brackenreed, agronomist with the Canola Council of Canada.

A pre-harvest herbicide application is very important for straight-cutting,” Brackenreed said.

“Something that’s difficult for producers to get used to in straight-cutting is that the stalks can be very green. That can make it difficult to feed through the combine. A pre-harvest application can really facilitate that and make it easier to combine the canola.”

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The pre-harvest herbicide should be applied at 70 to 80 percent pod-colour change, giving pods more time to fill. The crop is ready for harvest when seed colour is below two percent green. It’s often necessary to use at least 10 gallons per acre of water to get good coverage because the crop is often taller than the weeds.

Brackenreed emphasized that a pre-harvest herbicide is not the same thing as a desiccant. A desiccant prevents future maturity of the crop and locks in the number of green pods.

A herbicide treatment dries down the weeds but may still allow the canola plants to continue maturing to a certain degree.

She said one combination that growers use is an application of glyphosate tank-mixed with Heat LQ herbicide.

“Heat LQ does dry down the canola crop. Heat is saflufenacil, a Group 14. Heat has some systemic activity, but it’s mostly contact activity. So it’s a little slower acting than a product like diquat, Reglone.

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“So you can get some minor maturity and seed fill after application. Honestly, it’s a strange point to make. I don’t really know that it would push a person one way or the other. I think what’s maybe nice about Heat is that it’s not as concerning to lock in green seed. The timing isn’t quite as critical as with Reglone.

“The distinction between a desiccant and a pre-harvest aid is important. Some people think that with a desiccant you bring on maturity. You don’t. You really run the risk of locking in green seed and there are quality issues.”

According to BASF, Heat LQ in trials has given a more uniform crop dry-down of 8.33 percent compared to naturally ripened or glyphosate-alone treated stands. BASF stated that growers also saw better broadleaf weed control and easier combining after using Heat LQ.

Brackenreed added that straight cutting comes down to efficiency.

“ Swathing is obviously a slow process. It’s more manpower and another piece of equipment. But some larger farms look at it the other way. If you swath, timing isn’t as critical. If you have a lot of canola, you can put some of it down in a swath and it can sit there for weeks sometimes without losing quality or seed loss. With straight cut, it’s important you get to that crop when it’s ready to go.”

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For more information, contact Brackenreed at 204-720-6923 or brackenreeda@canolacouncil.org.