Grain yields must be corrected for moisture, otherwise wetter heavier grain will skew yields higher while drier, lighter grain will appear to decrease yields, says Matt Digman, University of Wisconsin Biological Systems Engineer.

“Changes in corn variety, moisture content and individual kernel density can lead to measurement error. It is recommended that a calibration load be entered every 2-3 weeks, or more often, if there are noticeable changes in crop condition,” he points out in a recent piece he wrote.

The moisture sensor’s calibration also needs periodic adjustment as conditions change. This process usually includes taking a few representative samples from the grain tank to the elevator for analysis; the values from the elevator are then used to update the combine’s calibration.

Calibration load recommendations vary depending on manufacturer. Some may have the operator find a consistently yielding, level area of the field, harvesting at an average rate while others have the operator harvest at varying rates throughout the calibration period. Those using non-linear calibrations may require the operator to harvest more than one calibration load, each time varying the harvest rate. Most operators’ manuals provide step-by-step instructions. It is important to follow the instructions specified by your operator’s manual. This process may seem involved, but most machines allow the operator to continue harvesting until the calibration load weigh ticket returns so harvesting is not impeded by a calibration update.

For more detailed information, read “Monitoring Your Yield Monitor.”