Waiting to swath canola leads to higher yields

The Canola Council of Canada (CCC) says growers who give canola crops time for all seeds to reach maturity can see a 10 per cent increase in yield. Agronomy Specialist Shawn Senko recommends swathing when the main stem shows at least 60 per cent seed colour change. 

Evidence for this later cutting time has been gathered over the years, starting with a Canola Council study from the early 2000s. Results showed that canola swathed at 60-70 per cent seed colour change (SCC) yielded 11 per cent more than fields swathed at 30-40 per cent. In 2013, Indian Head Agricultural Research Foundation compared two swath timings – 20-30 per cent and 50-60 per cent SCC – and found that waiting a week until canola reached the more advanced stage increased yields by nearly nine per cent. BASF trials found that 60 per cent SCC is the “sweet spot” for hybrids without the pod-shatter trait. For hybrids with the pod-shatter trait, BASF trials showed higher yields for canola swathed at 80 per cent and highest yields for canola straight combined.

A 2020 Canola Council survey of 1,000 canola growers suggests many are cutting too early, and leaving yield on the table. Of the growers who swath all or some of their canola, the survey found that half of them target an SCC of less  than 60 per cent when deciding to swath.

At 60 per cent SCC on the main stem, seeds from the bottom third of the stem will have completely turnedbrown-black in colour. Seeds from the middle third will be mostly brown, with some speckling and mottling. Seeds from the top third will still be green but firm to roll. Seeds that are mushy when rolled between the thum band finger are not physiologically mature and will shrivel up after cutting. With the main stem showing this level of maturity,seeds from side branches should also be firm to roll. If they’re not, growers may want to leave the field standing a little longer.

SCC will typically increase by about 10 percentage points every two or three days (quicker under hot dry conditions, slower under cool moist conditions), so waiting a week can provide a big boost inyield and potential profit.