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Calibrate Your Combine Yield Monitors!

Updated September 15, 2020
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Anthony Bly

SDSU Extension Soils Field Specialist

Additional Authors: David Karki
Farmer calibrating a yield monitor insde a combine cab.

The equipment associated with precision farming is a considerable investment and is a great tool for gaining knowledge about your farming operation, soils, crop varieties and hybrids, fertility program and planting equipment. The yield monitor is often overlooked as the critical piece of equipment when the crops are ready for harvest. Just seeing the varying yields on the screen while combining across the field is not the whole reason for having a yield monitor. Without a properly calibrated grain yield monitor, the farm cannot successfully assess the true yield information to use in accurate decision making for managing soil variability and crop management. Proper calibration solidifies the investment made in the precision equipment. Harvest pressure is immense when the crop is ready, but a well-planned approach and proper calibration will help get the job done much more effectively. Don’t think that mistakes made during harvest or wrong yield data can be corrected after the fact. Basically, the old adage of “Junk in = Junk out” is very true!

What to include in your grain yield monitor calibration plan?

  • Make sure your monitor controller screen is ready for this year’s data. Is there enough room in the internal storage or the external USB. Move last year’s data to an appropriate folder or even get a new USB storage device for the upcoming year. Review the owner’s manual so you understand and re-fresh your memory of the calibration procedure.
  • Power up the yield monitor and components and make sure everything is working and there are no error codes that would indicate a potential problem. Check all the components and wiring to make sure everything is connected well and wires have not become damaged.
  • Verify the scale on your weigh wagon or grain cart is accurate. This may include loading out some of last year’s grain and checking the weight on a certified scale at your local grain elevator.
  • Think about a field you might want to start combining and develop a plan for how you will vary the grain flow across the mass flow sensor. Don’t use headlands, end rows and poor field areas. There are two ways to vary the flow across the sensor. One can vary the speed of the combine to increase or decrease the flow or keep the combine speed constant and vary the width of cut at the header or the number of rows for corn. With either approach, the larger the area combined for each calibration load the better. Your yield monitor manual will suggest the quantity of grain and number of calibration points to combine for each approach.
  • Understand that re-calibration is needed as grain moisture or test weights may vary by farm location and crop variety/hybrid. A rule of thumb is that different mass flow sensor calibrations are needed for grain above and below 20%.
  • Do not forget to calibrate the grain moisture sensor to values measured at your local grain elevator or your own moisture sensor if you know that it corresponds with a certified grain moisture tester.
  • Temperature and vibration calibrations are extremely important as well. As temperature changes during harvest one should make adjustments as needed. Vibration calibration usually are conducted with an empty machine running at full rpm with the header lowered to operational height.
  • Back up your data. When harvest is slow due of poor weather conditions, use this time to back up your data.
  • Always consult your manual or quick reference guides for your specific system. Many are available on-line and can be quickly downloaded to your mobile device.
  • A well calibrated yield monitor will help increase the value of all other precision farming equipment. The timeliness of harvest when the crop is ready is very critical, but making a right plan for calibrating the combine yield monitor before harvest is also equally (if not more) important. Doing it frequently or whenever time allows will definitely help understand how to manage the data not only for this year but also the subsequent years.

Happy harvesting and always think of safety first!