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Yield Monitor Calibration: Getting Accurate Data

Harvest · October 2025 · 5 min read

Yield monitor data drives variable-rate prescriptions, land rental negotiations, and management decisions worth thousands of dollars. But uncalibrated monitors can be off by 5–15%, producing maps that mislead rather than inform. Proper calibration and data cleaning are essential for trustworthy yield data.

Multi-Load Calibration

Calibrate your yield monitor using at least 3–5 weigh-wagon or scale-ticket loads that span the range of yields you expect. Include loads from both high- and low-yielding areas. Single-load calibrations are insufficient because the relationship between mass flow sensor readings and actual yield is not perfectly linear across all flow rates.

Recalibrate when switching crops, changing header widths, or at the start of each season.

Moisture Correction and Sensor Maintenance

Yield monitors measure wet weight and correct to a standard moisture using the onboard moisture sensor. Verify moisture accuracy against a handheld meter or elevator moisture readings. An offset of 1–2 points of moisture causes a proportional error in reported yield.

Header Height Delays and Data Cleanup

Yield monitors record a time delay between when grain is cut and when it reaches the sensor. Incorrect delay settings shift yield data forward or backward along the pass. Set the delay according to your manufacturer's recommendations and verify by checking that high and low spots on the yield map match known field features.

After harvest, clean your data by removing start-and-stop pass artifacts, narrow passes, and outlier points. Most precision ag software includes tools for filtering these common errors before generating final yield maps.

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