With harvest quickly approaching, it’s time to make sure your combine is prepped and ready for the field. If you are going to harvest test plots or other strip trials with your combine, there are some additional steps you should consider to ensure high-quality data from test plots.
Evaluate status of yield monitor components
Many growers harvested downed crops because of the 2020 derecho. While it is recommended you inspect your combine and its yield monitoring components every year, it may be especially important this year for many. Debris in fields in 2020 (like metal from buildings, wood, etc.), as well as crops with more dirt due to being downed, may have prematurely worn components on your machine and could cause your yield monitor accuracy to be impacted.
Inspecting critical components like the impact plate, clean grain elevator paddles and chain tension as well as the crop moisture sensor to ensure they are in good condition and ready for harvest will help produce high-quality yield data. It’s important to remember that any adjustments made to the clean grain elevator chain tension will impact how the crop hits the yield monitor impact sensor, and is cause to recalibrate the yield monitoring system.
Calibrate the yield monitoring system
Ensuring the combine has a good multipoint calibration is a key first step to ensuring accuracy. Make sure the speed and yield of the crop being harvested in your trial area is similar to at least one point included in your multipoint calibration. This ensures the flow rate the machine will be operating at while harvesting your trial has a similar, scale-verified calibration point. It’s also important to do multipoint calibrations with weights from a well-calibrated grain cart or weigh wagon.
Crop moisture is often the biggest culprit for errors in yield monitoring systems. Ensure the multipoint calibration being used was developed with a crop of similar moisture. Moisture differences of as little as 2.5% could cause yield measurement errors of up to 5%. For step-by-step information on calibrating your combine’s yield monitor, the Iowa State University’s Digital Ag team provides an online interactive monitor guide.
Understand crop flow delays within machine
If harvesting continually through a strip trial or check block in a field, it’s important to understand delays in crop flow that are inherent with combine harvesters. On average, it takes about 13 seconds for grain to get from the combine head to the mass flow sensor. This delay depends on a variety of factors, such as header width, ground speed and the type of crop being harvested. Most commercial yield monitors attempt to correct for some of this delay in the display. By verifying that your GPS offsets and other machine parameters are properly set up, you can ensure the display will correct for this to the best of its ability. Failure to properly set up your display could result in the test block or strip trial not lining up correctly with other datasets, making analysis difficult.
It’s important to also understand that crop from the outside of the head takes longer to reach the feeder house than rows near the center of the head. This results in crop being merged along the forward travel distance of the combine. This distance changes based on header width and travel speed. Consider this when harvesting field trials and plots.
If continually harvesting through multiple plots, it will take a significant distance for all the grain from the first plot to pass by the yield sensor before you are completely measuring only grain from the second plot. When harvesting field trials, it’s recommended that a plot length be no less than 100 feet to account for this delay and collect the most accurate data.