The question is, how soon is too soon to combine after swathing? There is not set length of time that canola must stay in the swath before combining. If moisture is below 10% and green is below 2%, go combining. Two to three weeks of curing is just an estimate.
Canola at 10% moisture is at risk of spoilage when binned at 20°C. At 25-30°C, the spoilage risk is that much greater. Canola at 8% moisture is also at risk if not cooled immediately after storage.
The first 4-6 weeks are critical. Canola in storage keeps respiring during that time, releasing moisture into the air around the seed. This moisture moves with air currents inside the bin, and in the fall and winter, this moisture concentrates at the top of the central core.
A recent canola bag storage study concluded that:
—Harvest bags are best used as a short term storage solution under Prairie conditions.
—Dry canola (less than or equal to 10% moisture) can be stored for up to eight months and 12% moisture content canola can be stored for up to five months without any significant change in quality or grade using harvest bags during autumn and winter.
—Canola above 12% moisture content should be stored only for three to four weeks in the harvest bags to avoid quality and quantity losses.
Cutting canola hot can lead to fast dry down, which can trap green in the seeds. If canola green counts are still high (No.1 canola requires 2% or less) and seed moisture levels have dropped below 10%, further green clearing is unlikely…unless conditions change.
Canola seed moisture needs to get back up to 20% with temperatures remaining at 15°C or warmer for chlorophyll-clearing enzymes to restart and produce significant curing. An inch of rain will not lift canola at 7-8% moisture anywhere close to 20%. Several days of heavy dew, high humidity and additional rain events may be required.
Swathing canola when temperatures are hot can cause two potential problems for the crop:
1. Rapid dry down due to hot conditions does not give the green-clearing enzymes enough time to reduce chlorophyll levels in the seed, and green counts can be elevated.
2. Very dry pods can shatter if swathed on a hot day.
If late season hail damages pods, then these pods have a higher potential for shattering as they dry. Swathing early to save these pods may not be worthwhile if these pods represent only a small percentage of the yield potential of the crop.
Canola binned hot, even if it has low moisture, low dockage and low green, should still be put on aeration. This will even out the temperature throughout the bin, and help remove some of the moisture from respiring seed. Even at low moisture, air movements within the bin could concentrate this moisture.
Growers can lose up to 5 bu./ac. of canola during harvest, with many of those losses occurring as canola enters and exits the combine. Combine losses should be less than 1 bu./ac., and hopefully more like half a bushel.
Here are the top 10 tips to keep combine losses to a minimum…
Research conducted by the Canola Council of Canada over approximately 28 site-years indicates that significant yield increases can be achieved by waiting until 50-60% seed colour change on the main stem before swathing. Swathing at 50-60% SCC resulted in 8% more yield than swathing at 30-40% SCC, 12% more yield than at 10-20% SCC, and 19% more yield than swathing before 10% SCC.
The optimal swath timing for canola yield and quality is when 60% of seeds on the main stem are showing some colour change. Seed colour change (SCC) is considered any amount of yellow or brown on the seed.