Grain loss is the only harvest cost that never shows up on an invoice. It leaves the machine, lands on the ground, and the first evidence most people see is a green stripe next spring where the combine was running.
The frustrating part is that it is measurable in about ten minutes, and almost nobody measures it.
The loss monitor tells you a direction, not a number
Loss monitors are genuinely useful and routinely misunderstood. They count impacts on a sensor and give you a relative reading. They do not know how many bushels per acre you are losing, because they do not know your yield, your ground speed, or how much of the material is actually grain.
What a loss monitor is good for: telling you that something changed. You were at a steady reading, you went over a hill or into a different variety, and the number moved. That is worth knowing.
What it is not good for: deciding whether your loss is acceptable. For that you need to look at the ground.
The drop pan method, honestly described
Catch what comes out the back over a known area, separate the grain from the chaff, and count it. A commercial drop pan makes this easier, but a shallow box of known dimensions works.
The important details:
- Catch behind the machine while it is running at normal speed in normal crop, not at the headland
- Catch separately behind the shoe and behind the straw walkers or rotor if you want to know which one is losing, rather than just that something is
- Do it more than once. One sample in one spot is a guess
- Account for the spread width. If your machine spreads residue wider than your header, grain is landing outside your catch area and the count is low
Then convert. Count the kernels in your sample, divide by the catch area, and compare against seeds per bushel for that crop. Several provincial agriculture departments publish seeds-per-pound figures for prairie crops and those are worth having on the phone rather than working from memory.
What the number means
Here is where it gets interesting, and where the discussion is usually too simple.
Zero loss is achievable and almost always a bad trade. A combine set to lose nothing is a combine running slowly enough that you are paying for the lost acres per day somewhere else: in overtime, in weather risk, in the extra machine you needed to buy to get the crop off.
The right question is not "how do I get to zero" but "what is this loss costing me, and what would it cost me to reduce it?" At current canola prices, a loss that sounds alarming as a percentage may be worth less per acre than the extra day of combining it takes to avoid, and the opposite is just as often true.
Work it out in dollars per acre and the decision usually makes itself.
Where the loss is coming from
Catching separately behind the shoe and behind the separator tells you which half of the machine to work on, and they have different cures.
Shoe loss usually means the cleaning system is overloaded. Too much material, not enough air, sieves wrong for the conditions, or straw chopped too fine and loading the shoe.
Separator loss means grain is still in the straw when it leaves. Rotor speed, concave setting, feed rate, or straw that is simply too tough to let go of the grain at the speed you are running.
Header loss is the one that gets forgotten, and in canola it can be the biggest of the three. Shattering at the cutterbar, grain bouncing off the reel, material going over the back of the table. Check it by catching ahead of the machine, before anything has gone through.
Do it once a season and you will keep doing it
The first time most people measure their actual loss, the number surprises them in one direction or the other. Either it is far lower than feared, and they speed up and gain days; or it is higher than expected, and a half hour of adjustment pays for itself in a single field.
Either outcome is worth ten minutes.
Talk to our team
Our service departments have worked through loss problems on most of the machines running in this area, and the first conversation usually costs nothing.
Book a service appointment or browse used equipment.
