Canola growers often lose 2 bu./ac. out the back of the combine, and losses can easily reach 5 bu./ac. if the combine is pushed beyond its threshing capacity.
Every combine will have a sweet spot where the settings and ground speed are just right for the conditions and losses are within the acceptable range of 0.5-1 bu./ac.
The only way to find that sweet spot is to first set the combine concave spacing, cylinder/rotor speed, fan speed, and sieve and chaffer spacing to match the canola harvesting conditions, then use a drop pan to measure the losses for these settings. If losses are too high for your liking, adjust these settings or reduce ground speed until losses are acceptable. Use the links below to find more on measuring losses.
The Harvest Loss app from the Saskatchewan Soil Conservation Association can make it easier to quantify the seed loss from harvesting operations by converting a seed loss measurement taken during harvest into a loss per acre. The user enters the amount of seed in a sampling area of known size, either in weight, volume, or kernel number. The cutting width and sieve width are entered to determine the concentration factor. The app uses bushel or seed weight to calculate losses. These can be expressed in total loss (lbs/acre or bu/acre), as a percentage of yield, or as a cost.
Source : AlbertaCanola