Stay off the swather until most of the canola turns. Canola Council of Canada agronomy specialist David Vanthuyne says many canola fields are going to mature at different stages this year. He advises growers to hold off swathing until sufficient seed colour change has taken place.
Vanthuyne says averaging out seed colour change on a number of plants in several locations within a given field will be the most profitable approach this year.
“Staging will be critical”, he says, “some plants may be at 60 to 70% seed colour change while others may only be at 20 to 30% seed colour change. The trick is too capture as much yield as possible by delaying swathing long enough, avoiding shattering losses, but allowing as much seed colour change as possible on less mature plants.”
“When seeds in the bottom half of the plant have changed colour,” Vanthuyne says, “seeds in the top, or last formed pods, will be firm and roll between the fingertips. At this stage of maturity the risk of locking in green seed can be minimized.”
To be considered sufficiently “colour changed”, green seeds must have at least small patches of colour or spotting. Seeds slowly turn from green to light yellow or reddish-brown to black, depending on the weather and variety. Seed colour change within pods on the main stem will advance about 10% every two to three days under normal environmental conditions.
“We’ve extended the swathing recommendation window to up to 60% seed colour change from our old recommendation of 30 to 40%”, Vanthuyne says. “Unfortunately this year, variations in maturity in many areas will make determining when to swath more difficult.”
The Canola Council agronomy specialist advises growers to start inspecting canola fields approximately 14 days after flowering ends.
“After assessing the main stem, look at seeds from pods on the side branches to ensure they are firm with no translucency, especially in fields with low plant populations where typically the plants have numerous branches,” Vanthuyne says.
Under normal growing conditions, sampling the field every two to three days and averaging the percent seed colour change will give growers an accurate assessment of the overall maturity of the crop. Plant densities, soil type, topography, variety choice and weather will affect the rate of seed maturation. Vanthuyne says it’s a good idea to walk out and sample at least five plants in different areas of the field.
Some varieties will show pod colour change long before the seeds do, while the opposite holds true as well. That why it’s so important to check for seed colour change, not pod colour change.
Vanthuyne says that to catch most of the crop at or near the optimum stage, growers with large acreages may need to start swathing their earliest maturing fields prior to 40% to maintain an average seed colour change of 40 to 60% for the bulk of the crop.
Hot, dry and windy weather causes rapid seed moisture loss and seed colour change. “We’ve seen seeds on the main stem change from 10% to 50% in just a few days under these conditions,” he cautions.
Swathing late in the day and during the night will reduce shattering of riper plants and also minimize green seed issues by slowing the initial dry down of the swaths. “At the very least avoid swathing during the heat of the day, especially at 30 plus degrees,” stresses Vanthuyne.
“Patience and averaging seed colour change will be the key this year,” says Vanthuyne.
For a free copy of the Canola Council’s Time of Swathing Guide, contact admin@canola-council.org or (204) 982-2100. An on-line version is available at: http://www.canola-council.org/properstage.aspx
For more information in your area, contact:
Derwyn Hammond, Manitoba (204) 729-9011;
Jim Bessel, North Saskatchewan (306) 373-6771;
David Vanthuyne, Eastern Saskatchewan (306) 946-3588;
Doug Moisey, Parkland East (East Central AB & NW SK) (780) 645-3624;
Matthew Stanford, Chinook (Southern AB & SW SK) (403) 758-6660;
John Mayko, Parkland West (West Central AB) (780) 764-2593;
Anne Vos, Peace Region, (780) 835-4632
This press release is part of the Canola Council’s Canola Advantage program. The program is supported regionally by:
Alberta Canola Producers Commission;
Saskatchewan Canola Development Commission;
Manitoba Canola Growers Association;
Canola Council of Canada;
Peace River Agriculture Development Fund; and
B.C. Ministry of Agriculture, Food and Fisheries