FARMER/DAKOTA FARMER, February 2002
An ongoing study in the Minnesota River Valley hopes to find the "holy grail" of nitrogen (N) application:
How much N do you need to get the yields you want—without wasting money or sending unused N through ground and surface water?
Watonwan County farmer Bob Swanson farms a lot closer to Butterfield Creek than the Minnesota River, but he understands what he does on his land impacts the entire watershed.
"We're about 30 miles from the Minnesota River, but the water gets there."
Swanson joined seven other farmers in southcentral Minnesota to participate in the first year of a three-year study that originated at the Center for Agricultural Partnerships (CAP) in Asheville, N.C.
CAP was joined by other organizations such as the Minnesota Corn Growers Association and the University of Minnesota's Precision Agriculture Center in the project. Blue Earth County Consulting is providing management of the project for CAP.
The goal wasn't just to discover economical levels of the N application, but to share that information with other farmers in the project.
"It's the start of building a database," says study participant and Blue Earth County farmer Pat Duncanson.
That information can provide producers with the knowledge they need to save money. Duncanson says recent spikes in anhydrous prices (reaching more than 20 cents per pound) have forced farmers to rethink how they determined just how much N is going to be needed.
"In the past, it's been a lot cheaper to apply a little too much (N) to meet a crop's needs," he says.
Karyn Wassman, a senior field technician with Blue Earth County Consulting and project manager, outlined the details and criteria for the study:
Wassman says the weird weather of the crop season, a wet spring followed by drought, didn't damage the results from the first year of the study.
"We had a few fields that were drought-stressed," she says, "but overall the fields yielded about the same."
Wassman says economic N application rates came in at between 90 and 120 pounds for "optimum economic yields" determined by each test plot's average yield history.
"An extra 30 pounds may have produced a couple extra bushels," Wassman says, "but it wouldn't necessarily be economically sound."