By farmathand

Every farmer wants to get the most out of their hard work and one way to do that is to minimize combine losses during harvest. We connected with Derek Rude A.Sc.T. from PAMI (Prairie Agricultural Machinery Institute) and asked him some pointers to manage combine losses. Check it out!


How can farmers get the maximum efficiency out of their combines?
There are various sources of combine losses. The losses could originate at the header, grain leaks, threshing, separating, or cleaning systems. To get maximum efficiency out of your combine, the first step is to quantify the losses and determine if they are acceptable to your operation. Instead of relying only on visual check, quantify your loss in bu/ac for the information to be most meaningful. If the losses are not acceptable the next step is to determine where the majority of the loss is coming from. We use a plastic dishpan on the end of a broomstick and take a sample of the separator and cleaning shoe loss separately to visually see where the majority of the loss is coming from. To inspect for unthreshed loss disengage the chopper and inspect the condition of the straw to see if there are any unthreshed seeds in the head or pod.

Research over many years has shown that as feed rate increases loss increases. This information can be shown on a loss curve. Typically the feed rate (x axis) versus loss (y axis) curve will be quite flat until the capacity of the threshing, separating, or cleaning systems is exceeded. Once the capacity of one of these combine systems has been exceeded the loss increases exponentially as feed rate increases. The farmer should be targeting maximum productivity at their acceptable loss level which means that the combine should be operated at a feed rate where the loss curve is just starting to increase in slope. Determining loss at a range of speeds will allow the farmer to find this point of maximum productivity at a reasonably low loss level.

How to minimize losses in dry harvest conditions?
Typically you are looking at a dry canola situation when the crop material is very dry and brittle such that the crop material breaks down as soon as it enters the combine. What typically happens then is much of the crop material breaks up into small pieces and ends up being introduced to the cleaning system. To reduce the amount of crop material being introduced to the cleaning system you can install separator and or concave blanks to block off some of the concave and separator area. Another suggestion is to reduce the rotor or cylinder speed and or increase the concave clearance to reduce the threshing and separating aggressiveness which can also reduce the amount of crop material being introduced at the cleaning system.

What is an acceptable amount of loss?
It is not reasonable to expect that a combine is going to be 100 percent efficient in all crops and conditions. Typically around 1 to 2 percent loss should be achievable regardless of the type of combine you have or the crop condition you are in. There are some exceptions in challenging crop conditions where the loss can only be reduced to 3 to 4 percent at reasonable ground speeds; it’s not very common but it can occur. Measure your losses in bu/ac, for example if a typical yield is 50 bu/ac for canola then a 1 bu/ac loss (2 percent of 50 bu) is reasonable.

What is the best way to measure harvest losses?
The best way to measure losses is to drop a loss pan then clean the catch sample. The loss can be quatified by weight, by volume, or by seed count. The area of the drop pan will factor into the math required to determine the loss amount per acre. It is recommended to disengage the chopper and spreaders when doing loss checks to ensure the entire header width of crop material and loss is being collected in the loss pan.

There is a PDF version of a loss calculator here or an online calculator that can be very handy for all of the smart phone users here.

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