From Canola Council of Canada
We know canola losses occur out the back of the combine. Are losses high enough to warrant the time spent to reduce them? They certainly will be for some combines and in some conditions.
“Combines could be throwing over 5 bu./ac. and growers may not even realize it because those seeds are so difficult to see once they hit the ground,” says Angela Brackenreed, agronomy specialist for the Canola Council of Canada. “A pan is the best way to see these losses.”
Growers have a few pan options; there are pros and cons to every style, but any one of them is better than not measuring at all. They can buy or build a one-foot-square pan to mount on a stick held under the back of the combine. Deep sides will limit seed bounce out of the pan. They can toss a wide flat pan under the combine as it goes by. Or they can buy a more elaborate pan that attaches to the belly of the combine and can be dropped from the cab. The advantage with this pan is that the combine operator can also measure harvest losses. Brackenreed bought one of these to try out this fall.
“It works off an electromagnet bolted to the underside of the combine. It runs off the cigarette lighter receptacle in the cab, and to drop the pan you just unplug the cord,” she says.
The first step when using any style ofpan is to disengage the chaff spreader and straw chopper and move them out of the way. This allows straw, chaff and thrown-over seeds to drop straight down over the pan.
Once the combine is fully engaged and working through a typical stretch of crop, drop the pan. When using the pan on a stick, move the pan into position upside down so it doesn’t gather any losses ahead of time. Then quickly flip it over and stop walking. This procedure provides the same result as throwing the pan.
Remove straw and chaff from the sample, preserving only the seed. Measure the seed in the pan by weight or volume.
Calculate the loss based on one square foot. If the pan is two square feet, for example, divide the weight or volume by two to get the total for one square foot.
Here are a few scenarios:
- If the cut width (straight cut or swathed) is 30 feet, the combine’s discharge width is five feet, and the canola seed loss per square foot is five grams, the yield loss out the back of the combine is 1.5-2 bu./ac.
- If the loss for that same combine is 10 grams per square foot, the yield loss is over 3 bu./ac.
- If the same combine has a 40 foot header and the drop pan has 10 grams per square foot, the yield loss is closer to 2.5 bu./ac.