Krista Kirkham, Nature Conservancy assistant aquatic ecologist, gives details on cover crop research at the Franklin Demonstration Farm in Lexington, Ill. The tour was hosted by the McLean County Soil and Water Conservation District.
Krista Kirkham, Nature Conservancy assistant aquatic ecologist, gives details on cover crop research at the Franklin Demonstration Farm in Lexington, Ill. The tour was hosted by the McLean County Soil and Water Conservation District.

LEXINGTON, Ill. — A demonstration farm that focuses on conservation-oriented agricultural practices that benefit water quality in nearby streams has taken its research another step forward.

Research at the Franklin Demonstration Farm over the past seven years has found that wetlands significantly reduce the amount of nitrate and phosphorous runoff into the Mackinaw River Watershed. New studies are focusing on the affects of cover crops to further reduce nutrient loss.

“We’re trying to determine how effective these wetlands are in reducing nitrogen and phosphorous, but also what size do they need to be to have that kind of effectiveness,” Krista Kirkham, Nature Conservancy assistant aquatic ecologist, said during a recent tour of cover crop sites in McLean County.

“We started to build in this research by adding a cover crop,” she said.

This marks the third year of the cover crop research. The plots are located on the farm’s east side and a wetland system on the west side to compare the effectiveness of both systems in reducing nutrient loss in streams.

Various methods of applications and the type of crops are both examined in the corn-soybean rotation.

A cover crop mixture of cereal rye and radishes was applied aerially this year in corn, and annual rye was planted with a drill after soybeans the previous year.

“The tenant didn’t have to change his management practices because he does a burndown in the spring,” Kirkham said.

“This is a big learning process for us. This is the first time we’ve delved into cover crops and learning what to expect for the producers. We’re planning to do this project for a number of years,” she said.

The research is through a partnership between the Nature Conservancy, McLean County Natural Resources Conservation Service, University of Illinois and Illinois State University.

The cover crop research has two primary objectives.

“The main part is we’ve been doing wetland research on this farm for about seven years, but we wanted to incorporate the addition of cover crops to see if they can further reduce nutrients coming into tile drainage water, specifically in wetlands, and we think they will,” Kirkham said. “We want to be able to monitor that, and we’re lucky we have a nice research design to be able to do that.

“We have a side of the farm that drains into wetlands that we put the cover crops on and the other side of the farm also drains into wetlands with no cover crops, so we have a control and we have an experimental.”

The flow and content of water entering and exiting both the wetland and cover crop areas will be monitored to compare the effectiveness of each system.

“The second goal is for demonstration. We want to be able to show producers and landowners what they look like on a farm and have them be able to come out and ask questions, and we want to be able get enough data for not only just cover, but also more soil organic data, showing the nutrients in the soil itself to show improvements that way,” Kirkham said.

Soil testing will be conducted every other year through a partnership with ISU’s Agriculture Department.

Research at the site has shown the benefits of a wetlands system.

“Over the seven years, we’ve found these wetlands can reduce nitrate concentration anyway from 19 (percent) to about 47 percent, and phosphorous concentrations are reduced 45 (percent) to 55 percent,” Kirkham said.

“That’s not really considering the cover crop aspect yet. That’s pretty strong to be able to take to producers. Of course, the bigger the wetland, the more you’re going to see.

“We’re seeing some very significant reductions with the wetlands, and we’re hoping that with the addition of cover crops we’ll see even less nitrates and phosphorous coming through.”