I've spent the past few weeks talking about yield monitor calibration. The first article talked about how during calibration you are teaching the monitor to convert pressure against the flow sensor to pounds of grain. We also discussed that pressure against the flow sensor is related to grain flow. As a reminder, grain flow is a function of swath width, ground speed and crop yield. You can see those blogs below.
As you calibrate an Ag Leader system your goal should be to encompass the entire range of grain flow your machine will see during the harvest season. This means your high flow target should be near your machine's threshing capacity because for short periods during the harvest season you will run your machine near or at its capacity. This usually happens when you go through an area of extremely high yield. Conversely, you should account for the low end of flow as well. Extreme low flow is usually a function of harvesting low yielding areas.
To calibrate the system accurately, you need to find an area of consistent yielding crop where you can get five to six loads of around 3,000 pounds of grain per load. So if you are in corn that is yielding 150 bu. per acre your loads should cover about 0.35 acres. With an eight row head the length of a calibration run should be 770 feet.
The point is that you do not need a huge area of consistent yielding crop to calibrate your system.
Once you pick out your calibration area you should run each load at a different speed. To determine the proper speeds for each of the calibration loads, I have put together a set of tools that I usually share with the groups who hire me to put on calibration clinics. These tools allow you to gauge your high speed load to your machine's capacity and your low speed to the lowest yield you will see during harvest. The tools then help you to evenly divide the rest of the loads between the high and low.
If you are interested in these tools contact me (firstname.lastname@example.org) and we can work together to arrange getting these guides to you. Also, if you have a Brookside agronomic consultant in your area, you can contact them to receive these tools.
When you calibrate a John Deere monitor (prior to the 2012 S series systems) you must represent your calibration curve with one high flow point and one low flow point. For those of you with a 2012 S series combine follow the Ag Leader directions above as you are using Ag Leader components on your machine.
For older machines your goal should be to place your high flow point where you run your machine a majority of the time from the standpoint of flow. Your low flow point is going to be dictated by the monitor itself. When it comes to determining your high flow point I have tools for this as well. For the low flow point you should follow the directions in the manual for the optional flow compensation calibration. For soybeans or lower flow crops the flow compensation may not be necessary.
The entire procedure laid out in these four articles usually requires a four-hour presentation to fully cover the details. To really learn the ins and outs of calibration I have found this is what it takes. We have gone over Ag Leader and John Deere but we have not talked about the systems that come on Agco, CAT or the Trimble monitors. Each has its own set of dos and don'ts. If you or your group are interested in a more in-depth explanation let me know and we can schedule a clinic for you.