Swathing is less common in Ontario than harvesting directly and is primarily conducted in Northern Ontario. Swathing may be beneficial in short-season areas or where a producer has a lot of canola acres to harvest because of the opportunity to harvest earlier. Swathing may offer more complete dry-down of plants and may be preferred on fields with uneven maturity. For more information on evaluating maturity and equipment settings for swathing, consult the Canola Encyclopedia at www.CanolaCouncil.org.
The optimum stage to swath canola is when 50%–60% of seeds on the main stem have changed colour. Farms with large areas of canola can start swathing at 30% colour change to ensure that most acres can be swathed at near-optimum maturity without the risk of over-ripening, which leads to pod shattering.
When staging maturity, examine only those pods on the main stem. The pods at the bottom of a canola plant ripen first, so the pods at the top may still be green when the field is ready for swathing. Do not let premature ripening caused by Sclerotinia or Alternaria influence optimum staging to swath. Most of the crop yield will come from healthy plants. Pick a point at which most of the field is at the correct stage, ensuring that in less mature areas the seeds are green, firm and no longer translucent. Seed that does not ‘squish’ when rolled between fingers but is still green is adequately mature for swathing.
It often helps to swath when the crop is moist from dew or during a light drizzle. Leave the stubble tall enough, 25–30 cm (10–12 in.), to support the swath and anchor it in the field, and to minimize combine wear. Canola ripens and dries quickly in the swath. Usually 5–10 good drying days will lower the moisture so that seeds in the upper pods are firm. Canola seed can drop by 1% moisture or more per hour in the swath.
Combining
Green seed issues occur when chlorophyll is not degraded or cleared from within the seed. Check harvested samples by crushing seeds on a strip of paper and determining the percent of distinctly green seeds. No. 1 and No. 2 Canada canola grades may contain a maximum of 2.0% and 6.0% of green seeds, respectively. Hot or windy weather can result in seed moisture content that indicates it is harvest ready, before there has been sufficient time for green chlorophyll to disappear. Several dews or a light rain can help to clear the green colour from seed.
When harvesting canola swaths, adjust the pick-up speed and height so the pick-up runs just under the swath and it is gently lifted. Slowing down the combine travel speed can dramatically reduce harvest losses. Monitor and make adjustments throughout the day to minimize harvest losses. 54 seeds/m2 (5 seeds/ft2) on the ground equates to a loss of 1 kg/ha (0.9 lb/acre). Average harvest losses range from 10–50 kg/ha (9–45 lb/acre).