LEFT BEHIND One study found roughly two bushels are left behind on every acre of a canola field
Cinderella has a dark side.
Canola, the golden child of Prairie farmers, has become a major weed issue and reached No. 5 in the 2010 Alberta weed survey.
“It’s never been in the Top 10 before, suggesting tighter acres and rotations, but also higher prevalence in relative abundance,” said Neil Harker, research scientist and weed ecologist with Agriculture Canada at Lacombe.
“This is a relative abundance rank compared to other weeds.”
Harker has been studying harvest losses and presented his findings at a recent Alberta Canola Industry seminar.
On average, about six per cent of a canola crop is left behind after harvest, he said.
“There are a lot of sources of harvest loss,” said Harker. “It can happen after combining as well as behind the combine and behind the swath, depending on what happens during swathing. It can also happen based on the type of stand that you have, the pod-filling process and how uniform that is.”
One study found about 3,600 seeds are left behind on every square metre of a canola field — roughly two bushels per acre. That’s about 20 times the seeding rate, and therefore a good reason “to develop genotypes with very low secondary dormancy and reduce the volunteer issue,” said Harker.
One study found the germination rate to be about three per cent.
“We lost a lot to fatal germination in the fall and there were some that were eaten by beetles and other animals,” said Harker.
Research is ongoing into the factors contributing to harvest losses, but they seem to be going up.
“We’re certainly not improving, and we’re losing more seeds per metre — higher yields probably have something to do with that,” said Harker.
Researchers found straight cutting resulted in higher losses than swathing, but losses for both methods were lower when harvesting was done in the morning. Combine manufacturer and type made little difference to harvest losses. Higher seeding rates and good stand densities also reduced losses.