60 percent on main stem | Canola council says growers should hold off as long as possible to allow crop to mature
Swathing unevenly developed canola in wet conditions has a bright side. It can mean fewer losses and better quality.
“Swathing on those really hot, dry days is not ideal because it can lead to higher green seed content. Whereas swathing under these cooler, cloudier, even in a light rain shower isn’t a bad thing because it seems to help with the green seed,” said agronomist Warren Ward of the Canola Council of Canada.
“If it was just a light shower here and there and not really saturating the field then that’s almost ideal swathing conditions,” said Ward, based in Yorkton, Sask.
Canola in eastern Saskatchewan is highly variable, which typically corresponds to later maturity.
He said in some areas it’s almost like having two crops in the same field because of the different development stages the plants are in.
According to the council’s research, the best stage to swath is when there’s a 60 percent seed colour change on the main stem.
The council’s swathing guide states “delaying swathing of any canola variety up to this stage can typically improve yield and quality through increased seed size, reduced green seed and higher oil content, while avoiding economic shattering losses prior to or during swathing.”
Ward said growers with large canola acreages should wait until they see at least a 30 percent seed colour change before starting the swather.
“When you start looking at some of these fields that have a lot of variability — maybe there’s frost in the forecast, or excessive rains — a lot of other factors do come into play as well,” he said.
“If growers can hold off as long as possible before they do pull out the swather, that’s generally going to allow some of those later plants to advance more.”
Another consideration to watch for is the amount of branching and the maturity of seeds on them.
“That seed colour change is based on the seeds on the main stem, but if you have a plant with a lot of branches you really need to pay attention to those side branches as well, because they will be contributing as much or more to the yield potential as that main stem would be,” he said.
At this stage in the game, it’s almost a judgment call.
“Some of these fields that do have variable stages, a person just has to make the best guess at which part of the field is going to contribute most of the yield and manage based on that,” he said.
“At the end of the day, logistics are going to be that some fields are probably getting swathed too early and some of them will probably be too late.
“The weather being what it is right now, maybe they have more time to think about it.”