Your Reading List

A $75,000 Lesson: Use Your Yield Monitor

Josh Fankhauser figures a lesson learned from a 100-acre pea plot on his southern Alberta farm is potentially

either saving or making him an extra $75,000 a year every time he grows peas.

That sounds like a pretty exceptional return, but Fankhauser discovered paying attention to information collected by a simple yield monitor (and the corresponding yield map) from that 100 acres of pea seed led him to correct a dry down practice on the bulk of his pea crop that was costing him money.

Fankhauser, who is part of the family-run Lamb Farms Ltd. at Claresholm, about an hour northwest of Lethbridge, learned from the yield monitor that the unsprayed 100-acre block of peas being saved for seed yielded 10 bushels per acre more than the rest of the 1,500 acres of peas he had sprayed prior to the 2009 harvest.


While it may not be an exact figure, assuming he had been able to harvest an extra 10 bushels per acre over the entire 1,500 acres of peas, at $5 per bushel, in theory he would have grossed an extra $75,000 from the crop.

“We do a lot of research trials on our farm, but I think our mistakes teach us more than things we had planned,” says Fankhauser. “In one sense, we learned the way we were desiccating peas cost us $75,000 that one year. But if you flip that around now that we have made changes, we have the potential to increase our returns by $75,000.”

Fankhauser recently described this learning experience, and emphasized the value of using information collected by a yield monitor, at the annual conference of the Southern Alberta Conservation Association.

Fankhauser made the point that information collected from even a basic yield-monitoring and mapping system can be valuable to farmers, but they need to make use of the information.


A pre-harvest application of glyphosate is a common practice on Fankhauser’s farm. Applied just prior to harvest, glyphosate is a useful tool to help pulse crops dry down and also to control weeds, he says. But to protect seed viability and germination any crop being saved for seed should not be treated as it can affect germination if applied at the wrong time.

“We applied the glyphosate, but then after harvest looking at the yield map the 100 acres saved for seed showed up as this green patch —–higher yielding area — on the map,” says Fankhauser. “And we could see the yield on the 100 acres was about 10 bushels per acre higher than the rest of the crop.

“I did some investigation, and spoke to pulse crop specialists and realized that I had desiccated the crop too early. And that is what made the difference.” Pulse crop specialists say spraying a crop even a week or 10 days too early can adversely affect pod fill and seed weight, which ultimately reduces yield.


Fankhauser delayed his timing of pre-harvest glyphosate in 2010 and again using the yield monitor and mapping, along with check strips, did not see any significant yield differences between treated and untreated.

“We felt we had corrected the problem, but it was important to confirm that the following year,” he says.

Lamb Farms uses two John Deere combines to harvest their crop. A model 9600 machine has no yield monitor and a model 9660 does have a yield monitor. Fankhauser, who is keen on getting the most value of precision farming tools, makes a point of driving the 9660.


“We just have a basic system; the point is that you don’t need to make a big investment in technology, but we do need to make use of the information it provides,” he says. “In our case a mistake in the timing of glyphosate potentially cost us This yield map of the pea seed field shows a large area that is predominantly green (highest yield) bordered by areas that are spotted with blue and black areas that are lower yielding.

$75,000. But now, we have corrected that, thanks to our yield monitor and mapping, which cost $5,000. Hopefully we won’t have any more $75,000 mistakes. It doesn’t take long for a system to pay for itself.”

Fankhauser says it is important for farmers not to be afraid to talk about mistakes, because they are important learning tools.

Using the tools of yield monitor, yield mapping and auto steer he is able to conduct on-farm research trials every year to learn something. For example, using field trials with check strips, the information showed it made sense to reduce fungicide treatments, as yield information from those trials showed yields between treated and untreated crops were not significant. Fankhauser also regularly runs on-farm trials comparing new crop varieties, and he is just beginning on-farm trials into the benefits of variable-rate fertilizer application.

He also has a situation now where yield mapping will hopefully help him solve a production mystery in one part of a field. Yield mapping showed he has a clearly defined area in one field, roughly 200 feet wide and a half mile long, which is producing 10 bushels per acre less than the surrounding field. “So far there is no explanation for it, but when I see something like that, I want to investigate further to see what is causing the yield difference,” he says.

“On farm research plots need to be properly planned, but it is not that difficult,” he says. Fankhauser says it is important to make sure both research plots and check strips are large enough to be meaningful and easy to manage, and they should be created in the most uniform part of the field to minimize variability due to soil type and topography. It is also important the combine operator is paying attention so plots and check strips are properly harvested.

“Aside from this experience with the field peas, I would say overall using the information of yield mapping is making me an extra $10 per acre on my farm,” he says. “It is an important tool for helping you adjust inputs, and also in optimizing yield.”


So what is the proper timing for applying a pre-harvest treatment of glyphosate to dry down field peas? The label recommendation is to apply glyphosate when 75 to 80 per cent of pods are brown, and the average seed moisture is below 30 per cent. When the pods at the bottom, lower third of the plant are dry and the pea seeds rattle in the pod when shaken is another indicator of proper timing. Also do a thumbnail test on pea seed from the top of the plant. If you can split the pea with your thumbnail and no water emerges, the crop is at ready to be sprayed.

LeeHartisafieldeditorforGrainewsin Calgary,Contacthimat403-592-1964orby emailat [email protected]


We just have a basic system; the point is that you don’t need to make a big investment in technology, but we do need to make use of the information it provides

About the author

Field Editor

Lee Hart

Lee Hart is editor of Cattleman’s Corner based in Calgary.



Stories from our other publications