OSU Researcher Studies Farm Runoff

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The grasses planted to the right of the tree line help curb fertilizer, such as phosphorus, that could get into the stream that runs through Bret Davis' farm in Delaware. Ohio State scientists are studying runoff at 30 farms in the state.(Photo: WOSU News)
The grasses planted to the right of the tree line help curb fertilizer, such as phosphorus, that could get into the stream that runs through Bret Davis' farm in Delaware. Ohio State scientists are studying runoff at 30 farms in the state.(Photo: WOSU News)

Scientists believe that farm fertilizer containing the chemical phosphorus recently caused unsafe levels of toxic algae in drinking water in Toledo. One of the main sources of phosphorus is farm runoff. But phosphorus is essential to crops. Ohio State University scientists are looking for a solution.

Ohio State soil scientist Libby Dayton is working with the U.S. Department of Agriculture to find out just how much fertilizer drains out of Ohio farm fields.
Dayton is studying 30 farms in the Scioto, Grand Lake St. Marys and Western Lake Erie Basin watersheds. The latter two have the most serious problems with toxic algae.

“We have…monitoring equipment at the edge of their field, and we’re collecting, on most fields, a surface or tile runoff. So we’re collecting all the water that’s coming off of their field,” Dayton said.

This is the project’s second year. In addition to collecting runoff and soil samples, Dayton said the farmers share their field management methods.

“We can see everything they’re doing on the field and relate that to what we see coming off the field on an event basis, every rainfall event, every runoff event,” she said. “And that helps us quantify what was going on in the field at that time and how it relates to what we see coming off the field.”

The researchers’ goal is to make sure the state’s Phosphorus Risk Index accurately reflects the amount of phosphorus farm runoff.

The Phosphorus Risk Index – or P Index – was originally created to assess runoff risk, but now it provides management practices and regulations. Farmers use it as a guide to develop fertilizer plans for their crops.

Dayton said updating the index will be invaluable to farmers as they try to reduce phosphorus runoff.

“It isn’t helpful if you tell a farmer, well, you have a bad P Risk Index score if then you don’t offer…practices [that will] decrease your P Index score,” Dayton said. “That’s what the farmers are asking us for. They’re asking us for what can we do, what can we change, and will it really help? And so that’s the tool that we’re ultimately trying to deliver to the farmer.”

Bret Davis owns a farm north of Delaware.

“We have a mix of corn and soybeans. We farm about 3,800 acres between my stepson and myself,” he said.

Davis is not part of the P Index study, but he’s very interested in its findings. Davis, who began farming in 1978, says fertilizing practices have changed considerably just in the last five years.

“For every half acre in our field we know exactly what goes on that half acre,” he said. “So that we’re not putting on any more than we need but we put on enough to grow that crop.”

Davis said he planted large filter strips around a stream near his soybean field to quell the runoff.

“Can we go look at it? Sure. Sure. Jump in the four wheeler there and we’ll take a ride.”

Davis cranks up his four wheeler and drives it across the street to a dirt path. Soybeans are plants on either side of it.

“As you see here this is an old quarry…This is the starting sides of the stream. And here on the backside, you can see as the stream goes out of the quarry, I’ll so you the filter strips that are on both sides of that stream.”

The field strips Davis talks about are tall, natural grasses he planted about six years ago. They’re between 30 and 60 feet wide.

“It doesn’t look like much, but it’s just a natural buffer that we keep nutrients out of the streams because this stream feeds into the Olentagny [River],” he said.

OSU’s Libby Dayton has collected thousands of samples in the edge of field testing. She said so far, the analysis has shown significant runoff differences between farms.

“By seeing that, I think we’ll be able to offer some really good insights to help reduce for the farmers that may be having a problem,” Dayton said. “The good news is that many of the farmers, there’s very, very little coming off the fields. We have a lot of farmers that are doing a really good job and already initiating best management practices.”

A $1 million USDA grant funded the project. Ohio farmer groups provided $1.5 million.

  • Keith Pritchard

    Much more than Ohio needs to be involved. The Maumee has roots in two rivers converging in Indiana as do rivers and streams going to Grand Lake St. Marys. Also, Lakes Huron and St Claire coming down towards Toledo are bordered by Michigan ( as well as a questionable processing by Detroit) as well as Ontario the bread basket of Canada that borders those lakes plus Lake Erie. Ohio is a smaller contributor than most think and has done a lot already to clean things up. Toledo’s water treatment was also dated. They complain about cattle and dairy manure but birds and poultry have much higher amounts of phosphorous, and I can’t imagine the huge over populations of canadian geese don’t have some effect, especially since they are grass eaters near water. As well most issue of the toxic blooms came after the rapid invasion of zebra mussels. Since they have a proclivity to eat the beneficial algae that supports the lake ecosystems over the toxic cyanobacteria forms the toxic algae have been opportunistic in filling the vacuum of nature left by them eating much of the good algae. No coincidence the toxic forms started coming back in the 90′s after the mussels took over. I would suspect more would be beneficial to find a likely genetic method of changing the diet (maybe to a preference of toxic algae)or controlling the populations of the mussels.