Harvest losses can add up at higher speeds

BALGONIE, Sask. — There is a tradeoff between pushing hard at harvest and losing bushels out the back end of the combine.

Nathan Gregg, project manager of applied agricultural services at the Prairie Agricultural Machinery Institute, said it’s understandable that farmers want to take crop off as fast as possible, especially if rain is coming.

However, they also need to understand what they could be losing and whether the economics make sense.

He told producers at the Indian Head Agricultural Research Foundation’s annual crop management seminar that losses of one to two bu. per acre are common, but he has seen it as high as 15 bu. per acre.

Even the lowest losses can be significant.

Gregg used an example of 160 acres of canola, worth $10 per bu. and combined with a 40-foot header.

At three m.p.h., or 14.5 acres per hour, one bu. per acre is lost over the 11 hours it takes to complete the field.

Pushing the combine to four m.p.h. allows the operator to combine 19.4 acres an hour, but the loss climbs to three bu. per acre over 8.2 hours.

The time saved on the field is 2.8 hours.

“It’s fair to assign a value to that,” Gregg said.

The Saskatchewan rental rate guide suggests $250 to $400 per hour, and Gregg chose $300 for the example.

“You just saved $840,” he said.

However, the cost of losing one bu. per acre at three m.p.h. is $1,600, or $145 per hour.

At four m.p.h., the loss is $4,800 or $585 per hour.

“There’s a difference of $440 an hour just by going that one m.p.h. faster,” Gregg said.

“So it cost $2,360 to go one m.p.h. faster.”

He said each producer must calculate that cost against the cost of leaving a crop in the rain.

“Too often, we don’t make that economic calculation,” he said.

“You’d be surprised how quickly any losses would offset any gains you expect to make by saving a grade or being done early.”

Gregg said farmers have misconceptions about their combines, and clearing them up could help manage losses better.

The main one he hears is that farmers can go faster because they have a new combine and more capacity. He said that’s true, but they need to add “at a specified loss rate” to their statement.

“Really, I can make any combine go seven m.p.h. in 50 bu. wheat, depending on how much I want to end up in the tank behind me.”

Another misconception is that more power equals more capacity.

Gregg said that’s true sometimes, but there are times of day and weather conditions when extra power means nothing.

Another misconception is that keeping the machine full will reduce loss. This began when rotary combines were first introduced in the 1990s and the industry thought that multiple exposure and grain-on-grain threshing would work better.

“There’s a tiny morsel of truth in that a rotary does work better when there’s some material in there to thresh against,” he said.

However, putting more material in will eventually equal more coming out the back.

Farmers also tend to believe that their losses can’t be that bad when they use a state-of-the-art machine. They think they should be able to drive faster than their neighbour who uses an older machine.

Gregg said it’s important to remember that combines weren’t necessarily built for Saskatchewan conditions.

“By and large, these machines have been developed around a corn and soybean market,” he said.

As well, improvements made in engineering and design don’t all come at once.

For example, using a larger header can easily put 20 percent more material into the feed.

“Suddenly we’re asking our combine, even if we have optimized it, to do 125 percent of what it was doing before,” Gregg said.

Combines shouldn’t be set and left untouched because weather and crop conditions will change over the course of a day.

Loss monitors are a useful tool, but many people don’t really understand how they work or what information they are providing. Gregg said he’s been in the combine with operators who complain the monitor has been reading high all day, so they turn down the sensitivity and receive a false sense of security.

He advised farmers to read the manuals to make sure they know how monitors work.

He also said they need to leave their comfortable combine cabs and get down in the dirt to check their losses. They can use a trap to catch what’s coming out the back and measure losses.

“All of this equals dollars — dollars we could have in our pockets,” he said.

PAMI and other organizations provide loss calculators on their websites.

Contact karen.briere@producer.com

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