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.
10. Check for leaks. Losses do not always come out the back end. Before making any adjustment to cylinder speed, concave spacing, fan speed or sieve spacing, check over the combine to make sure you don’t have any leaks. Look for holes and cracks on the pickup, feederhouse, elevator, shoe seals, separator covers and the grain tank.
9. Check the combine operators’ manual and look at the range of settings for canola. Are you within those ranges? If not, try that first. Try one variable at a time and check losses between each adjustment. Check that the automatic settings on newer combines are calibrated. For example, if the chaffer setting on the monitor says 18mm, take a ruler and check that the chaffer spacing is in fact 18mm.
8. Adjust fan speed to the point where seed is just beginning to blow over.
7. Open chaffer and sieve settings as wide as you can tolerate.
6. Avoid over-threshing. Straw pulverized into small pieces that drop down to the sieves will reduce air flow and separation — and increase losses. Cracked seed is another sign of overthreshing. Consider lowering the cylinder speed or widening the concave setting. This adjustment may also make it possible to drive faster and keep losses constant.
5. Don’t assume canola separates easily. Unthreshed pods in the chaff mean the combine is underthreshing. Increase cylinder or rotor speed, narrow the concave setting, add concave blanks, or slow down.
4. Rotaries work best with a narrow windrow, like a ribbon. Conventional walker combines work best with a wider swath that creates an even mat over the full width of the cylinder and walkers.
3. Feed canola as uniformly as possible into the combine. Take time ahead of harvest to smooth out bunches left by the swather. Losses as these big bunches move through the combine can be huge. Note that smoothing out piles is best done at or shortly after swathing. By combining time, these piles are brittle and more likely to shatter..
2. Measure the actual loss out the back of each combine. See the article in this issue for tips how to do that.
1. Travel at speeds that match a level of acceptable loss. It may take just a small decrease in speed — say 0.2 or 0.3 mph — to provide a significant reduction in losses. The loss curve tends to remain fairly flat until ground speed reaches a critical point when combine capacity is taxed, then the loss curve can rise steeply.
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