With this season’s crop in the bin, it’s time to plan how to keep next year’s yields trending upward, says Ken Ferrie, Farm Journal field agronomist. That requires examining what went right and what went wrong in every field.
Here’s how the process works for Ferrie and his Crop-Tech Consulting staff:
1. Review the past season.
“Calibrated yield maps are the best tool, if you have them, but include every layer of data you have — planting and application maps, scouting reports, drone or satellite imagery,” Ferrie says. “Determine why every field performed as it did, whether good or bad. Have all equipment operators and scouts present — when something unusual shows up, one of them might remember the cause, such as animal or wind damage. You’ll get more buy-in on next year’s plan because they’ll realize the importance of every individual and every operation.”
2. Were yield differences caused by nature or man?
“Man-made problems usually show up on a map as straight lines or streaks,” Ferrie says. “They might match up to passes with tillage tools, planters, sprayers or nitrogen applicators.”
3. Is the yield difference real or only on the map?
Review all applications to determine if the difference resulted from a software or equipment issue. “If you find streaks were caused by the monitor, you usually can recalibrate them to get them closer to the actual yield,” Ferrie says. Some software problems to watch for:
- With most yield monitors, speeding up might give you a false lower yield reading; slowing down gives a false higher reading.
- Dirty or gummed-up moisture or pressure sensors might record a false yield change. Causes can include mud picked up while harvesting downed corn and sap from black nightshade berries.
- Calibrating the monitor in mid-field might cause a change in yield. “Better to recalibrate at the end of the field,” Ferrie says.
- Multiple combines in the same field might cause streaking because of different calibrations. “If you verify that harvest loss is equal between the machines, identify the most accurate combine and use software to calibrate the others to it,” Ferrie advises.
4. Straight-line streaking might be hybrid-related.
“If one hybrid appears to perform differently, you’ll need to review scale tickets to get the actual yield,” Ferrie advises. “Even calibrated monitors have trouble picking up actual yield changes between hybrids due to changes in moisture and test weight. For that reason, you should not use only combine monitors to evaluate hybrid plots.
“On the other hand,” Ferrie continues, “monitors can show how hybrids respond to management zones. Querying out management zones can help reveal hybrid weaknesses and strengths. For example, some can’t stand wet feet and others can’t handle drought.
“If you base decisions only on scale tickets, you might drop a hybrid for poor performance,” he adds. “But monitor data might reveal that it shines in certain management zones. This could happen with a defensive hybrid (suited to low populations) in a field with mostly offensive soil (highly productive, suited to high populations). Some of our most valuable time with yield maps is learning which hybrids or varieties belong in which field.”
5. Some streaks are not hybrid-related.
Put on your detective hat and analyze various layers of data, such as planter downforce; smoothness of ride; ground contact; and insecticide, fungicide and/or fertilizer applications, especially when it comes to sidedressing.
“If streaks appear on aerial images taken during the growing season, we can learn when an issue first showed up,” Ferrie says. “Then we might be able to pin the issue to herbicide or fungicide streaking.”
6. After identifying all man-made streaks, study management zones.
“Look for correlations between yield and features like soil type, topography and poor drainage,” Ferrie says. “Each year will be different. In dry years, light ground shows up as poor yield. In wet years, low ground and sidehill seeps show up as low yield.
“Knowing where we ran out of water, we can vary next year’s plant population to match the soil’s water-holding capacity,” he adds. “Knowing which zones ran out of nitrogen, we can change the nitrogen rate or timing or use a stabilizer.”
7. What if new zones show up?
If no one knows what caused them, visit the site. “If tillage hasn’t been done, take stand counts and predict ear count based
on stalk diameter to determine if stalk or ear count was reduced,” Ferrie explains. “If the zone has been tilled, pull soil samples to check fertility levels and nematodes.”
Finally, write a plan for each field, continuing successful practices and fixing the problems. “If you write your plan down, you’re much more likely to follow it,” Ferrie says.
