• Header height sensor: While most people don’t pay much attention to this sensor it is important to check it and make sure it is working correctly. This sensor engages and disengages the logging mechanism for the yield monitor. Incorrect acreage leads to incorrect yield estimates.

• Distance calibration: This is very minor, but it is a good idea to recalibrate or verify it is working correctly. Again, incorrect acreage estimates lead to incorrect yield estimates.

• Vibration calibration: Make sure that before you get started harvesting you do a vibration calibration. This will correct the system for the vibration of the machine, especially when the header is engaged. It is recommended this be done each time you change the header on the combine.


Calibration is the most important step in collecting accurate data.

• Mass flow sensor: Harvest 5 individual loads around 100 bushels each. Weigh each individual load using a weigh wagon or truck scale. Record each weight. Once completed enter each load into the yield monitor for calibration. Note: The John Deere yield monitor requires you to enter each harvest load after each weight. For AgLeader or CIH you enter the weights at the end of the 5 harvested loads.

• Moisture sensor: While collecting the harvest weight loads, collect a moisture sample with either a handheld moisture tester or at an elevator. Most yield monitors only want one moisture reading to calibrate, so either take an average of the 5 readings or select one that is most representative of the group. I like an average.

Once these 2 steps are done you should be ready to go.

One word of caution. As the season progresses and the crops get dryer it is important to do a calibration check periodically. Grain test weight and moisture will affect the accuracy of the data.

As we get closer to cotton harvest time I will send you some information regarding cotton yield monitors. We are getting an increase in cotton yield monitors in the state with growers buying modulating pickers.

So to help with this, Edisto REC, with the help from Clemson Extension administration, made a commitment in the last few months to purchase a portable scale to calibrate these systems.

If you have any questions, or need help with calibration, please feel free to give me a call at 803-284-3343 (office) or 803-300-1-31 (mobile). You can also e-mail me at whende2@clemson.edu.