“Information about placing canola on forages is very limited, so caution is a definite must here”
Producers who have made the decision to put canola into fields previously in forages do so with a degree of risk, says Anastasia Kubinec, oilseed business specialist with Manitoba Agriculture.
“Information about placing canola on forages is very limited, so caution is a definite must here,” Kubinec told one of Alberta’s Canola College meetings here.
She said that to create the best canola stand, forages need to be thoroughly terminated before the canola crop is seeded. Kubinec said that for a field that was in perennial grasses or has cloddy soil, wheat or flax may be a better option in the first year.
She said an examination of the seedbed is crucial. Soil full of clods could create problems for canola emergence. Canola needs good moisture conditions and forage residues in the soil should be breaking up. Soil testing is very important when planning to grow canola after forage, she stressed.
Earlier forage termination will generally increase the moisture level in the soil, leaving more available for the canola. Good forage control and termination will reduce the amount of moisture consumed by volunteers. The method used for forage termination will have an impact on soil conditions, as will the type of forage previously grown in the field.
Kubinec said trials by Stewart Brandt of Agriculture Canada in Scott, Saskatchewan have found canola yields could be reduced by 15 per cent if forage termination was not done properly. Volunteer forage and regrowth could present problems.
“Your costs could be quite high as you try to control that,” said Kubinec. She said producers may want to delay seeding of canola for an additional year, as volunteer forages can also interfere with canola quality at the time of harvest.
Perennial forages can be tough to kill and not all herbicides will kill them. Kubinec said producers should check labels to ensure in-crop herbicides will not damage canola. She recommended consideration of the right herbicide-tolerant system.
“If you have a lot of weeds in your field or you can’t control your weeds, you’re not going to get the genetic yield potential out of your canola,” she said. “You need to make sure you’re combining the herbicide tolerance system to the weeds that you have.”
Producers using a no-till system need to watch their thatch layer, said Kubinec. Seeding deeper is an good option as seeding canola inside a thatch will reduce moisture avaiability. She said increasing seeding rates may also be a good strategy.
A pure alfalfa stand may be a little more suitable for canola as it has more nitrogen. If the forage stand was mixed, it may require additional nitrogen.