What is in this article?:
- Aerial images can identify or confirm a problem and its extent.
- Getting the image is only the first step. The real value comes in specific identification of crop problems by ground-truthing and follow-up plans that make sense economically.
- In most cases, interpretations and opinions from experienced agronomists or crop advisors are helpful in both correctly identifying and solving problems.
Light green lines in a 2012 cornfield show nitrogen deficiency resulting from a malfunctioning manure drag hose, right down to the width of the applicator.
Consider a three-way look at your crop — from above and below and at ground level. That means a close-up look at plant roots and soil for clues to plant growth, plus aerial images to detect, confirm, and define a problem.
I learn things from aerial images I didn’t pay attention to before,” says David Feldeverd of Melrose, Minn. An example, he says, is how much nitrogen is left in the soil in the second year after he’s plowed down alfalfa.
“I don’t like to over-apply nitrogen, so I follow University of Minnesota guidelines,” Feldeverd says. “But the aerial photos of my land this year show I’m running out of nitrogen in the second year after alfalfa, especially in sandy, irrigated soils. I think they’re giving too much credit to nitrogen from alfalfa in the second year.”
Feldeverd also confirmed a manure drag hose malfunction that left nitrogen-deficient strips. “We thought we could see it in knee-high corn,” he says, “but with the photos you could see it right down to the width of the 24-foot applicator.
“It’s amazing what you can pick up from these photos,” says Feldeverd, who’s in his fourth year of a five-year EQIP contract for water quality improvement on his farm. He’s testing nitrogen use in on-farm strip trials with help from the Stearns County Soil and Water Conservation District and the Iowa Soybean Association’s On-Farm Network.
The aerial photos from GeoVantage are included as part of the cornstalk nitrate test package the Iowa Soybean Association On-Farm Network uses with field strip trials to assess how much nitrogen a crop uses. Feldeverd is one of a 34 farmers enrolled in the Guided Stalk Nitrate Sampling program. A dozen farmers have replicated strip trials. When they get together each December with Stearns SWCD conservationist Mark Lefebvre, the aerial images start the discussion of their nitrogen programs, basal stalk nitrate results and yields. “They’re all pretty interested in the aerial images,” Lefebvre says. The interpretation includes input and guidance from an experienced rep of the On-Farm Network.
“Aerial images put you in the right part of the field and can give you advance warning to crop problems,” says Terry Panbecker, manager of high-tech Midwest Agronomic Professional Services (MAPS) in Ft. Dodge, Iowa. “Ground-truthing is absolutely essential.” His MAPS technology division is owned by New Co-op in Ft. Dodge and offers precision-ag solutions to ag retailers in several Midwest states.
Crop advisor clients use aerial images to scout fields, assess stands and find or verify prevented planting areas or plant damage from aerial hail and anhydrous, he says.