A common impact plate sensor, which is located at the top of a combine’s clean grain elevator.

Information from yield monitors can help you make better decisions on hybrid selection and placement. It can also help identify yield-influencing factors that you may not see from simple field observations. However, your interpretation and decisions are only as good as the quality of your yield monitor data – and that requires accurate calibration.

Getting your yield monitor ready for harvest involves a series of steps to make sure that the estimation of each data factor is accurate. Pay particular attention to the following components:

Mass Flow Sensor – Impact Sensor

• What it does: Measures grain flow (lb/sec) through the clean grain elevator in the combine.
• Why calibrate? Because of what it measures, this is by far the most important calibration of all.

Moisture Sensor

• What it does: Measures grain moisture content.
• Why calibrate? Calibration ensures that the moisture sensor in the clean grain elevator accurately estimates grain moisture content. Moisture sensors will adequately measure grain moisture when in the 10 – 33% range.

Temperature Sensor

• What it does: Measures temperature
• Why calibrate? This helps ensure mass flow sensor and moisture sensors are interpreting content correctly.

Lag Time Settings

• What they do: Measure time it takes grain to travel from the header to the mass flow sensor.
• Why calibrate? Total travel time typically ranges between 10-15 seconds. Subtracting 1-2 seconds from total measured time should remove the time that grain travels from the mass flow sensor to entering the bin. This compensation for grain flow delay allows for more accurate yield mapping.

Header Position Settings

• What they do: Controls when yield data should and shouldn’t be recording
• Why calibrate? Proper settings ensure false yield data is not being recorded while no crop is being harvested (for example, when turning at ends of rows).

Header Cut Width Setting

• What it does: Determines number of rows by row spacing
• Why calibrate? Incorrect setting of harvest width or harvesting a partial header width can lead to incorrect yield estimates. Weight calibrations should be performed again if header width changes in season.

Reference your owner’s manual for calibration methods specific to your equipment.

Quick Tips for Calibration

• Harvest and calibrate using a wide range of hybrids with different grain moisture
• Harvest a minimum of 3,000 lbs. per calibration load
• Use a minimum of 4-8 calibration loads to properly calibrate
• Harvest each calibration load at different load rates. For example, use different harvest speeds (e.g., 3 mph, 4 mph, 5 mph) for each load.
• Calibrate separately for each individual crop planned to harvest
• Make sure the weigh wagon or grain catch cart scales used for calibration are accurate
• Do not unload on the go while calibrating

For additional recommendations, speak to your local NK® retailers.

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