Consider swathing canola now — or at least a few days before the next expected killing frost, according to Manitoba Agriculture, Food and Rural Development’s oilseed specialist Anastasia Kubinec.
And if standing canola is frozen, be prepared to swath it as soon as possible, she said in an interview Monday.
Swathing too soon can reduce canola yields and potentially lock in green seed colour, but yield and quality can also suffer after a killing (-2.2 C or lower) frost, she said.
“Even if they’re at 20 to 30 per cent seed colour change and it sits (in the swath) for three weeks it’s probably going to be OK,” Kubinec said. “The important thing is if it’s standing and they get a -2 C for a couple of hours… you need to look at your fields and if those pods are starting to dry down really quickly you do need to knock it down to try and save those pods.”
Heavy speckling on canola pods is a sign of severe frost damage, which can result in pods drying quickly, popping open and spilling seed or detaching from the canola plant and falling to the ground, she said during the CropTalk Westman webinar. Either way, yield is lost.
If pod speckling is light and pods are still pliable Kubinec recommends watching the crop closely.
Freezing green-seeded canola can lock in the green colour because killing the plant stops the enzymes that normally remove the green from mature canola seed, Kubinec said. However, the wet-dry cycle swathed canola normally goes through over a number of weeks can help remove the green colour.
“Normally we say swath at 60 per cent seed colour change but as soon as the calendar turns to September… we say if you’ve hit 40 per cent and it looks like a frost is coming knock it down,” Kubinec said.
The least mature canola Kubinec has seen is in southwestern Manitoba, west of Highway 10 and south of Highway 2.
“That’s the stuff that’s at risk if we get a frost,” she said. “Most of the other canola is past that 30 per cent colour change and guys are probably knocking it down already.”
Wet weather delayed spring seeding in much of western Manitoba this year.
— Allan Dawson is a reporter for the Manitoba Co-operator at Miami, Man.