There is a lot of evidence that the best time to swath canola is at the 50 to 60 per cent seed colour change stage, but every year assessing seed colour change and actually swathing at that ideal time can pose quite a challenge,” says Angela Brackenreed, Manitoba agronomy specialist for the Canola Council of Canada.
While most farmers can seed a tremendous number of acres in spring really quickly, getting those same acres harvested takes a lot longer. Not every acre is likely to be swathed at just the right time.
The best time to swath
“Personally, I prefer swathing as late as possible without risking inducing shattering losses,” says Brackenreed. “In practise, that means starting to swath around the 50 per cent seed colour change (SCC) and targeting being completed at about 75 per cent SCC. There is about a 10 per cent change in seed colour every two to three days, so this gives you about a week to complete swathing.”
But farmers can start planning for swathing canola long ahead at seeding. “Planning for swathing canola should start before ever entering the field to seed,” says Brackenreed. “Choosing varieties with different days to maturity and possibly breaking up canola seeding operations are considerations, however, the latter is not always feasible given a particular farm’s manpower and equipment, and the type of seeding window we have to work with.”
- From the Manitoba Co-operator: Swath canola when 60 per cent of main stem seeds turn colour
Up until fairly recently it was recommended to swath canola at the 30 to 40 per cent SCC. “Now the recommendation is to swath at 50 to 60 per cent seed colour change ideally,” says Brackenreed. “However, if you have a lot of canola to swath you may have to start a bit earlier.” Every year, there are many farmers that don’t swath at the ideal time usually because of time, equipment or labour constraints. There will also be fields that do not mature evenly and it becomes a necessity to swath at a less than ideal time.
The SCC recommendations are made based on seeds on the main stem. “This has been brought into question lately as a lot of farmers are comfortable with thinner stands where there is much more branching happening,” explains Brackenreed. “Typically most of the yield comes from the main stem, but when there is a lot of branching, that may not hold true. In low plant populations where there is significant branching I recommend consider the SCC on the whole plant, not just the main stem.”
Brackenreed also points out that canola ripens from the bottom up and the inside out, so a plant with a lot of branches will take longer to mature.
Brackenreed is an advocate of straight cutting canola, and advises that a mix of both straight cutting and swathing can alleviate the problem of swathing at improper times.