Work continues on farms in hopes of protecting Lake Erie
While cooler NAPOLEON — fall temperatures arrive, agricultural field research into the causes of western Lake Erie algal blooms remains a hot issue, with more scientific detective work on the horizon.
Through grants provided by the U.S. Department of Agriculture, Gov. Mike DeWine’s H2Ohio program, major universities, and other sources, teams of researchers are still gathering samples and hoping to fine-tune ways the agricultural community can keep more of its nutrient-laden water on its fields and lose less into creeks and streams whose waters eventually flow into the lake.
One such research project involves “legacy phosphorus” fields.
Soil tests show such fields contain far more phosphorus than they need, in large part because of past agricultural practices when testing was rare and little was known about overapplication of fertilizers, according to Jay Martin, a professor in Ohio State University’s Department of Food, Agricultural, and Biological Engineering.
Martin is part of a team working with a group of Northwest Ohio farm operators who have such highly enriched soil. Many have asked for anonymity. Researchers have agreed to respect that in order to get more cooperation.
“We’ve known for some time those (legacy phosphorus) fields have a disproportionate amount of phosphorus running off their fields,” Martin said. “We had to find farmers willing to work with us.”
Although researchers are only midway through a fiveyear collection effort, Martin said it is believed that only about 5% of Northwest Ohio farms fall into the category of legacy phosphorus far
At least one of those fields is in Henry County, where the current operator, New Vision Farms of Napoleon, is cooperating with researchers, because it wants to be a good steward of the land.
“Our goal is to pass it on to the next generation in better shape than we found it,” said Mark Hoorman, New Vision Farms’ agronomy manager.
He said it’s in farmers’ best interest not to waste fertilizer in the first place.
“That’s what a lot of people don’t understand,” Hoorman said. “Phosphorus is so expensive, why waste it?”
Another thing many don’t grasp is that more phosphorus doesn’t always equate to a better yield, he said.
New Vision hasn’t been getting the yields it wanted from one 150-acre Henry County field it began managing about five years ago, and some of that field’s weakest performing sections are where the legacy phosphorus is highest, Hoorman said.
It is looking into other ingredients the soil there may lack, such as calcium, and has no plan to add more phosphorus as long as soil tests continue to show that running high, he said.
“That our ultimate goal: to use up what’s there,” Hoorman said.
In addition to soil tests, some of northwest Ohio’s legacy phosphorus fields have contraptions on them for what’s known as “edgeof-field” research, which has been expanded over the years by U.S. Department of Agriculture researcher Kevin King, and others.
Machines collect rainwater flowing off fields’ surfaces and underground through drainage tiles, allowing researchers to examine the quality of discharges year-round into creeks, rivers and streams.
Bottles containing such samples are collected at regular intervals. The devices even have their own internal heating mechanisms to keep them from freezing in the winter.
Why some fields hold in a lot of phosphorus and others don’t is a mystery, Martin said.
It’s also not known why plants on some fields seem to take up phosphorus more efficiently than others, he said.
Legacy fields could be ones that had overapplication of manure in years past, but that’s not the only reason.
New Vision is believed to have inherited a field where excessive sludge from wastewater treatment plants was applied in years past. Overapplication of synthetic phosphorous pellets could also explain it, but that is less common because of commercially made fertilizer’s high cost, Martin said.
Hoorman said he was surprised when soil tests showed how much phosphorus was in one of the fields New Vision now operates. Levels vary, even within sections of each field themselves.
“I think it’s extremely important to get the science down on this, instead of just making statements,” Hoorman said.