Monday, September 05, 2011
Calibrate Your Yield Monitor For Profitability and Better Management
Many Cornbelt farmers are already harvesting, because of early maturity driven by the heat and lack of moisture; and others are trying to prevent grain loss from weak stalks that are in jeopardy of a stiff breeze. Nevertheless, getting the best field data possible from a weather-ravaged crop in still important, and it all begins with proper calibration of your yield monitor.
If you are using your yield monitor to make future farming decisions, it needs to be properly calibrated says John Barker of Ohio State University. His guide to calibration says every unit is subject to errors, despite manufacturer efforts of accuracy. Barker says it may take 3-5 test loads of 50-100 bushels each in a weigh wagon for a good calibration. He suggests each test including a variety of flow rates, accomplished by different combine speeds. Also consider periodic recalibration throughout the harvest season, particularly if you are harvesting grain with higher moisture levels. The moisture sensor should be calibrated, as well as the temperature sensor.
Barker offers an extensive checklist to ensure your yield monitor is properly calibrated:
1) Before you begin using it in the field, ensure the unit itself is working properly. Put the data from the prior season in a separate computer file, and delete those from the unit. Check out the data storage devices to make sure they are working properly. The unit may have software upgrades available, so contact the supplier or visit their website to check.
Since it was last used, rodents may have visited its cables and data can be garbled if cables are damaged. Check and replace if necessary. Also check the moisture sensor if it is mounted in the combine elevator to ensure it is clean and any mechanical clean out devices are working and the doors will shut. Inspect the flow sensor along with wear on any of the paddles, and check their proper spacing. Deflector plates should also be checked and replaced if worn. If you will be using a used combine for the first time, ensure the yield monitor was installed properly by the prior owner. Cables should be isolated from other wiring and not part of a bundle because of potential interference from wires carrying voltage.
2) Before calibration, Barker says ensure that your memory devices are installed and no memory errors are occurring. You should be receiving a good GPS signal for accurate readings. If you monitor has a switch that is turned on and off by the header height, check to ensure it is operating properly. Set the proper width of the platform or number of rows being harvested, and engage the separator to determine if the monitor is picking up the correct speed from the elevator.
What scales will you be using to weigh your test grain? Calibrate your weigh wagon and leave it at one point in the field so it does not lose its calibration being hauled through a rough field. If you are going to an elevator, the scales are likely certified, but make sure you are using the same scales throughout your testing.
3) During the calibration process, Barker suggests making your temperature corrections in field conditions, and not rely on the monitor to correct the temperature difference from the machine shed to the field. Moisture tests should also be made on representative samples from each test load. Speed calibration should be made in the field on typical rows, not on a roadway or over a waterway where wheel slippage is different. Make your flow rate corrections at different flow rates, since it varies in the field, and don’t start or stop on a turn when grain is not flowing into the combine. If you are using the monitor for test plots, re-calibrate your monitor if you are harvesting different types of grain. Barker says high oil corn will have a different weight than conventional corn. He also suggests recalibrating with wide moisture variations of the grain.
4) During harvest, Barker says corrections are necessary if there are problems indicated by the monitor, particularly if sensors are not working or the DGPS signal is not being received, and don’t forget to turn it back on, if it was turned off at some point. He also recommends periodic recalibration if the harvest season is long or if there is more than a 5% variation in test weights or 10 degree change in temperature. While the monitor will store vast amounts of data, back up your data storage to ensure an electrical system failure or nearby lightning strike does not erase it. Re-calibration is also needed if you replace some of the components or adjust the elevator chains.
Summary:
Yield monitors can be valuable equipment to not only record important field data, but give instant feedback on problems you detect in a field. The weak link in the chain is whether the monitor was properly calibrated and continues to provide accurate information. Many things can cause a monitor to provide inaccurate data, and preventing those problems can ensure your monitor is a valuable tool in your management system.
Posted by Stu Ellis on 09/05 at 12:00 AM | Permalink