Swathing Canola and Seed Color Change

Pros and Cons of Chemfallow

Best time of year for many farmers is harvest time, since this is when one gets to see all their hard work is paying off. Although the itch to get out into the field to start swathing is there, keep in mind that swathing to early or on hot days can result in shrinkage and yield loss. According to the Canola Council of Canada, the optimum stage to swath is up to an average of 60% SCC on the main stem. It is important to note that sunscald can make pods look riper than they actually are, a scout through the field prior to swathing can help determine if that is the case. Research has found that swathing at 60% seed colour change (SCC) resulted in 8% more yield than swathing at 30-40% SCC (Canola Council of Canada). Weather impacts the rate of change in seed colour change. An average fall day, moisture loss may be 1-2% points per day. Warm to hot and windy conditions, moisture loss can be 2-3% points per day. A rough guide is that a 10% increase in SCC occurs with about 5% points of moisture loss. Swathing during daytime temperatures in the 30s or high 20s should also be avoided. Swathing at night is beneficial because of the cooler temperatures and moisture from dew. Despite the temptation to get out in the field, focus on correct timing and your patience will pay off. Happy harvesting!


By Nadine Robin, A.Ag