Since June has arrived, its about time we should be preparing for wheat harvesting. And this is the perfect time for us to set up a precision yield mapping system in the harvester. This of course is essential because we need to have an optical representation of our field and its spacial differences in terms of wheat yield. If our theory is correct, we expect better yield in places with high NDVI index values. So yield map will look similar to the NDVI map in terms of different colors.
For this experiment, we are going to use a CASE 2388 AXIAL FLOW harvester. In order to understand how this set of sensors work, you have first to understand how a modern harvester works. Watch the following video for this purpose:
So, its important to understand that in the final stage of harvest, grain is transferred in the silo with the so called grain elevator. You can see this elevator in the previous video in minute 1:40. What happens is that when the harvester passes from a place with high yield, the elevator carries more grain than it would curry when passing from a place with less yield. In the top of the elevator, grain is thrown in the silo. What we did is to install a load cell in a place that grain is going to hit. So the more grain you have, the bigger the force is applied in the load cell. Check out the image for better understanding.
Except for these values, we need to acquire GPS signal and grain moisture in order to conduct proper normalization in data. Moisture sensor is installed also in the side of the elevator so as to take small samples of grain and calculate moisture constantly. Check once again the image for better understanding.
After this is finished, what we need to do is to calibrate the system so as to acquire correct data. And of course this is because every combine is different and the system is universal. Calibration is quite easy actually. The only thing you have to do is when you finish harvesting a field, you have to check the average production calculated in the yield mapping system and then weight the actual yield. Then you can add the real weight in the system settings and all values measured will be normalized.
Check out some photos from the harvester onsite!
Let's hope we will have measurements very soon! Stay tuned for updates.