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How To Measure Grain Loss

So, you’ve decided to get dirty by getting down on your hands and knees and rummaging through the straw behind a combine to see exactly how many kernels the machine is throwing over. But how do you make sense of what you find? It’s unlikely you can avoid losses altogether.

For last year’s harvest issue ofGrainews,Les Hill, manager of business development and technical services at PAMI (Prairie Agricultural Machinery Institute), gave us his best advice on how to measure and interpret combine losses. In case you’ve forgotten what he said and used that issue to start a fire in the wood stove last winter, here’s what you need to do.

First, you want to start by using a catch pan to make finding and collecting grain loss samples much easier. Putting a broom handle on a rubber pan that has an area of one square foot will allow you to easily place it in exactly the right spot. Taking a one-square-foot sample makes calculating the loss in bushels per acre a much easier process, unless you really enjoy a mathematical challenge.

Once you have the sample collected, remove all the MOG (material other than grain). Then weigh the kernels on an accurate scale.

Next, determine the concentration factor. That is the ratio of the header (or swather) width to the width of the discharge at the back of the combine. For example, a combine equipped with a 30-foot header and a five-foot discharge width has a concentration factor of six (30/5 = 6).

Finally, use the accompanying chart (found in the June 2010 issue or on the Canola Council of Canada website) to relate the weight of the sample collected to overall pounds of loss per acre. Make your bushel-per-acre conversions from there.

And what target range should you aim for? Both Hill and Kelly Kravig, platform marketing manager for Case IH combines and headers, agree that reaching 99 per cent efficiency with your combine is an achievable goal.

Hill points out that while missing that target by only one or two per cent may not sound like much, any excess loss comes directly out of a farm’s profits. The more grain you leave in the field, the lower your profit margin. So, the time you spend fine tuning combine adjustments could be the most valuable hours or minutes you spend in a season.



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