September 7, 2004
Expert: Yield monitor calibration ensures data that computes
WEST LAFAYETTE, Ind. - A finely tuned combine can make a farmer's job less stressful during fall harvest. These days that means not only engines, tires and mechanical parts in peak condition, but also the high-tech gadgets that calculate corn and soybean yields.
While farmers are checking and rechecking their harvest machinery they would do well to include yield monitors on their to-do lists, said Stephen Hawkins, assistant director of Purdue University Agricultural Centers.
Poorly calibrated yield monitors result in inaccurate data, Hawkins said. Wrong data can, in turn, lead to misguided management decisions.
Hawkins urged farmers to inspect yield monitor components and related electronic equipment now before the harvest rush begins. Hawkins and Jeff Boyer, superintendent of Davis-Purdue Agricultural Center in Farmland, Ind., will address yield monitor issues during "Tips and Tricks for Accurate Yield Estimation," an afternoon tour stop at Purdue's 2004 Agronomy Field Day.
The free field day takes place from 8:30 a.m. to 3:30 p.m. Sept. 14 at Purdue's Agronomy Center for Research and Education (ACRE). ACRE is located five miles west of Purdue's West Lafayette, Ind., campus on U.S. 52.
Other field day tours look at corn demonstration plots, hybrid tests and research, pests, grain quality and autosteer technologies.
Yield monitors, introduced about a dozen years ago, measure grain volume as a farmer drives a combine along a field. The data is stored on a computer memory card, or PCMCIA, where it can be downloaded onto a laptop or desktop PC. If working properly, a yield monitor can determine bushels per acre to within a 3 percent margin of error.
To ensure the equipment performs as intended, farmers should follow the manufacturer's recommendations for installing and calibrating a yield monitor, Hawkins said.
"The moisture blade has to be cleaned and calibrated, and the elevator sensor needs to be installed properly and recording the right speed," Hawkins said. "Producers should make sure all the components are in good shape. They should check the wiring because mice like to chew on them, and that could cause errant readings. Producers also need to take the PCMCIA card out of the console and download it periodically so that they capture data."
In addition to routine yield monitor maintenance, farmers must use the equipment correctly, Hawkins said.
"There are five basic rules for yield monitor systems," he said. "Calibration loads should weigh between 5,000 pounds and 16,000 pounds to get enough weight and flow rate as it ramps up from zero and back down. Second, keep the speed constant for each load that is done. Third, perform the calibration on a field area that has uniform yield. You can check this by pulling some hand samples and making observations.
"Harvesting less than a full header width can help develop the low flow rates for the calibration curve. A farmer also can use low flow rates for generating the calibration curve on the low end by slowing the combine speed. Finally, make sure to keep notes. If you calibrate only once a year, a lot of times you'll have to relearn some of the details."
Hawkins offered these additional yield monitor tips:
• Consider the yield tracking differences between crops, grain moisture levels and harvesting speed. A farmer may need to calibrate a yield monitor more than once per field if conditions vary.
"When setting up these calibration loads, be mindful of which crop you are in. Is it a different hybrid? Is it wetter or drier? Is your groundspeed changing dramatically? All those things can affect the calibration load information and, consequently, the yield calculations for the field," Hawkins said. "If yield monitor calculations are off or aren't calibrated correctly, they can give inaccurate readings."
• Run calibration tests in fields with consistent yield levels. If using a six-row header, slowly shift to a five-row simulation, then four, and on down to one. "Many times you'll have to manually enter that as you're going through point rows or finishing a field," Hawkins said.
• Inspect the impact plate within the yield monitor carefully. If dirt or other material has built up on the plate where incoming grain makes contact, the yield monitor might fail to record the complete volume.
• Review yield monitor operating procedures beforehand. If necessary, make a "cheat sheet" and hang it inside the combine.
"One farmer we worked with forgot to push a certain button when he was recording loads," Hawkins said. "He harvested 800 acres without recording one bit of data."
For more information about Agronomy Field Day, including directions to ACRE, visit the event Web site.
Writer: Steve Leer, (765) 494-8415, sleer@purdue.edu
Source: Stephen Hawkins, (765) 494-8370, shawkins@purdue.edu
Ag Communications: (765) 494-2722; Beth Forbes, forbes@purdue.edu
Agriculture News Page
Related Web site:
Purdue Department of Agronomy
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