dpilot83 - 2/20/2013 15:05

In this thread I've had some dialogue with a few people in regards to how to post-process yield data. Before that conversation I was under the impression that you could get some useful data even if calibration wasn't perfect. Now I'm leaning towards the calibration process being extremely important, especially if multiple combines are involved.

We hire all of our harvesting done. The crew we hire runs six S670's with 2630's. I just talked to them and throughout the conversation I sensed the same disenchantment with technology that I have frequently felt when upgrading equipment with high expectations for good results. He explained to me that when they were down south cutting irrigated corn (before our corn was ready) they spent a lot of time carefully calibrating two of the machines. When they were done with that field the machines indicated that the field had yielded within 1 bpa of what the other machine said. At the end of the next field the first combine said that the field had averaged 20 bpa higher than the second combine said. At the end of the third field the first combine said that the field yielded 20 bpa lower than the second combine said.

After their initial and thorough yield calibration process, they did not change anything, they were just harvesting. The operators of the two machines were brothers and partial owners of the crew so they knew what they were doing.

This description is in stark contrast to what I frequently read on NAT and hear from others. Many times I hear that a properly calibrated yield monitor will read within 1% to 2% of what the scale tickets say. I know there is variability in fields but these combines were just following each other back and forth staying close together on fields 1 mile long so that the grain cart could be more efficient. There is no way that they could have experienced yields that were 20 bpa apart from one another.

So what's the problem? Are John Deere yield monitors not as accurate as Ag Leader monitors still even after they have Ag Leader sensors and an Ag Leader style calibration process? Is our harvest crew doing something wrong? Is it something else? Any thoughts would be much appreciated. Thanks.