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Yield Monitor Performance in Hilly Terrain

Location: Moscow, Idaho

Combines: John Deere 9870 STS

Crop Type: Wheat, Chickpeas, Beans

The Challenge:

Giving farmers a yield monitor that works in a region with notoriously hilly fields and the confidence to make farm management decisions based on quality yield maps.

The Solution:

FarmTRX Yield Monitoring technology addresses the design limitations of common factory yield monitors in hilly and non-uniform terrain.

Why Does it Matter:

Farmers need accurate yield data in order to put a dollar value on their farming decisions, no matter the field conditions.

Overcoming Yield Monitor Inaccuracy in Steep Topography

For crop consultant Doug Johnson, traditional yield monitors just haven’t been reliably accurate enough to justify the cost for his clients. The hilly topography of the region renders most mass deflector plate style monitors inaccurate, leaving his customers at a disadvantage with fewer options for yield mapping their fields.

Johnson serves farmers in the rolling hills of the Palouse, an agricultural region of the Inland Pacific Northwest famous for its hilly terrain. In their Northern Idaho region some fields boast 30 to 40-degree verticals, that’s ski-slope steep. That steep and rolling terrain undermines the accuracy of traditional factory yield monitors.

So when Johnson learned how FarmTRX Yield Monitors work differently from most factory systems, and could perform despite his challenging harvest conditions, he was intrigued enough to trial FarmTRX.

For Johnson, the difference in FarmTRX’s yield measurement technology meant being able to get accurate yield maps, no matter how hilly his client’s fields.

Of course the proof is in the doing, so after learning about how FarmTRX works differently, Johnson agreed to a field trial. Johnson’s client, farmer Clint Zenner, installed a FarmTRX Yield Monitor on his John Deere 9870 STS combine which was already equipped with the factory yield monitor.

Harvest was already underway when the field trial was proposed, but a rainy-day delay was enough time to install the system. With patent-pending QuickConnect technology for the optical sensors, installation can be completed on any combine with a clean grain elevator in under three hours, no matter the make, age or model.

Why FarmTRX?

Many factory yield monitors use a mass deflector plate system of measurement. Installed at the top of the grain elevator, a mass deflector plate measures yield mass based upon the impact force of the grain hitting it as it exits the elevator and falls into the hopper.

But, when harvesting uphill, gravity reduces the impact force. Conversely, when harvesting downhill, the impact is increased by gravity. If a farmer decides to harvest a slope at an angle, then some grain misses the plate altogether.

With FarmTRX, yield is measured by the mass volume. Two optical sensors, a transmitter and receiver, are installed on either side of the clean grain elevator. They capture yield volume on each paddle as it passes, measuring the “blocked” time when the receiver does not see the transmitted beam. Since grain is measured as it’s moving up the elevator, not as it impacts against a plate, field slopes don’t affect the accuracy of recorded yield.

“FarmTRX were the best results we’ve ever seen. We saw consistency and accurate yield mapping of the slopes and the soil,”


Greater Yield Map Accuracy than the Factory System

To understand how FarmTRX measured up against the factory yield monitor, Zenner diligently calibrated both systems on his John Deere 9870 STS the following season. After harvesting, Zenner compared the weigh ticket results from the elevator for one of his typical hilly fields.

The elevator proved that total yield for the field was 24,937 bushels. The FarmTRX Yield Monitor was within 2.7% or 677 bushels in recorded yield, while the factory monitor was off by 11.7% or 2,911 bushels.

To Upgrade Equipment or Not?

Besides accuracy, Zenner discovered that FarmTRX Yield Monitors have a high degree of sensitivity to small yield differences, information that would ultimately help him make an important farm management decision.

The yield map for one of Zenner’s fields showed striping often seen due to multiple combine miscalibrations or variety trials. For instance, if a farmer plants two varieties with a 16-row planter (eight rows of one kind and eight rows of another) they typically harvest them separately with a 8-row combine header to compare varietal performance. This can visually show up on a yield map as striping.

But the team at FarmTRX knew that Zenner’s field was harvested with a single combine and wasn’t in varietal trials. So, the pattern didn’t make sense. When asked, Zenner explained that this chickpea field had a constant 6-7 degree slope to it. The striping in the yield map resulted from harvest loss as chickpeas rolled off the front of the combine header on a downhill pass.

Traditional yield monitors typically struggle to register anything below 15 bushels per acre, even in flat, easy conditions. But the FarmTRX Yield Monitor is sensitive enough to register down to four bushels per acre and small, but important, differences in yield.

For Zenner, this level of yield sensitivity provided valuable decision-making information. He had considered investing in an expensive flex-draper header to minimize header loss during downhill passes. But before using the FarmTRX system, he had no way to know how much yield he was actually losing. The yield map determined only a 4% yield difference between his uphill and downhill passes, not enough to justify an expensive equipment purchase using resources that could be put back into the farm elsewhere.

Zenner can rely on his FarmTRX yield maps to explore the effect of different harvesting techniques on yield loss and retention. For instance, he can trial harvesting slopes at a slight angle and monitor the yield data to evaluate return.

For farmers who are comparing varieties, FarmTRX’s yield measurement sensitivity means there is no need to follow a complicated (and confusing) harvest process harvesting a trial field in two batches. Instead, they can harvest the whole field and use the yield data to compare varietal differences.

This level of fidelity is also helpful for organic growers with weed infestations that may end up as low-yield areas that otherwise wouldn’t record any yield on a traditional factory yield monitor.

Sold on FarmTRX Yield Monitors

Convinced of the Yield Monitor’s accuracy and performance in hilly terrain, Johnson has since become a reseller, encouraging his clients to rely on FarmTRX for capturing their yield data.

“FarmTRX yield monitors have improved my business and provided my customers with verifiable results they can rely on,” Johnson says.