What the yield monitor does monitors is always flowing through, but the rate at which it’s flowing might change. Therefore, the data could change depending on the speed of the flow. The yield monitor measure grain coming through the tank, but there could be huge delays after the grain goes through the header to the grain elevator. If there is a huge change, the monitor smooths it over mathematically and averages the numbers. The most important points that these inaccuracies matter is upon entering or exiting the fields. At the first, the combine begins, but won’t finish processing its first bit of grain for 15 second. During that time it travels 110 ft and harvests 4/10 of an acre. This is all before the yield monitor has registered a good reading.
Software usually makes up for such delays and corrects the data. In the end, the map won’t be a perfect depiction of yield, but good enough for looking at how yield differed across a farm.
This, and GPS data, along with mapping software can make a beautiful map that shows the grain harvested and the moisture of that grain. The real utilization of these maps is to incorporate them into future planning and decisions about the farm.
Sensors for Yield and Moisture
To measure the flow of grain, there is a sensor where the clean grain streams. The sensor might measure: how hard the grain hits the plate, how much light comes through the grain, the weight of the grain for a measured time, or how much grain is on the elevator. The most popular measurement is how hard the grain his the plate which is at the end of the elevator. Calibration is dependent on how fast the elevator goes, what kind of plant, how moist the grain is. Moisture and yield data must be measured at the same time to get accurate readings.
How to Calibrate and Have an Accurate Yield Monitor
A monitor needs calibration for accuracy. At the start of each crop’s harvest, the machine needs to be calibrated to that grain. It is best to use several loads to calibrate. Then, monitor the machine and re-do the calibration if needed. This is particularly important when the moisture of the grain changes (as the season goes on), or if there are other big changes to the crop. To calibrate the machine, simply record the moisture content and weight of the first few loads in a lot of different conditions (like different speeds of flow or operating speeds). Look at the yield monitor’s manual for exact instructions.
A yield monitor’s accuracy doesn’t just come from how it’s made, but also from how it’s calibrated. A manufacturing company might make training videos or session available for good calibration. Yield monitors are all quite different in how they need to be calibrated, but all of the calibration methods include weighing loads of grain – which isn’t easy for all farmers, logistically.