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Bioreactor field day proves to be a learning day

By Janet Kubat Willette

Date Modified: 09/16/2010 10:38 AM

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WASECA COUNTY, Minn. — There is more scrutiny than ever before on what's coming out of the tile outlet, Leonard Binstock said.

Binstock, of the Agricultural Drainage Management Coalition, spoke at an early August bioreactor field day that included classroom time at the Southern Research and Outreach Center in Waseca and a visit to a bioreactor under construction near Waldorf.

Things like nutrient trading in the Chesapeake Bay and efforts to rein in non-point pollution sources will impact agricultural drainage, he said.

"Those things are going to be coming, whether we like it or not, they're going to be coming," Binstock said.

He encourages drainage contractors and landowners to be proactive in addressing those concerns. Drainage contractors may want to suggest landowners install bioreactors or controlled drainage. Government financial incentives may be available for landowners to install water conservation practices, either through the Conservation Stewardship Program or other programs.

In the last five years, the federal government has invested a significant amount of dollars in on-farm research projects through 319 Clean Water Act grants, Binstock said. Without that funding, some of the projects wouldn't have been installed.

A 319 grant provided 75 percent cost share for the $14,508 project visited on the field day, said John Billings, Cobb River Watershed Project coordinator. The project included controlled drainage, installation of a bioreactor, stream bank stabilization and installation of a creek buffer.

The Greater Blue Earth River Basin Alliance applied for the 319 grant through the Minnesota Pollution Control Agency to address non-point source pollution problems within the Watonwan, Blue and Le Sueur River Watersheds, Billings said. The 319 grants are administered through the MPCA, which reports back to the federal Environmental Protection Agency.

The Waldorf area project is in the Cobb River Watershed, which is within the Le Sueur River Watershed. The Le Sueur River Watershed has issues with turbidity and sediment, said Scott MacLean, watershed project manager in the MPCA Mankato office.

The practices installed on the property will, hopefully, if adopted at a large enough scale, start to address the issues of turbidity on a larger scale, MacLean said.

The combination of practices installed on the site show there's no one cure all to address all water quality issues, MacLean said. It demonstrates that a variety of practices are needed to address stream impairments.

The woodchip bioreactor will denitrify the tile water that flows through, reducing the nitrogen reaching Bull Run Creek that flows along one side of the field, he said. The controlled drainage helps hold back some water by raising the water table slightly, MacLean said. Hopefully, the controlled drainage will make the system less flashy and result in less soil erosion.

Under certain situations, controlled drainage may even increase yields, MacLean said. Richard Cooke, associate professor in the Department of Agricultural and Biological Engineering at the University of Illinois in Urbana-Champaign said that in general the yield benefit appears to be minimal.

The stream bank stabilization and buffer should also help keep sediment from entering Bull Run Creek, MacLean said.

This project and another nearby one are two examples of landowners being proactive, MacLean said. Hopefully, by being proactive, landowners will be able to get ahead of any kind of regulations, he said. The two sites are also good demonstration sites for other producers.

On the field day, the bioreactor was a 12 foot by 22 foot hole with a fourth generation control structure on one end. Participants talked about what size tile to use and how the bioreactor would work. They walked over to look at where the tile would outlet into Bull Run Creek.

Since then, the hole has been filled with woodchips, said Mark Dittrich of the Minnesota Department of Agriculture. The work is done and the oats, bromegrass, perennial rye and timothy seed planted and covered with a straw blanket are growing.

It was challenging to fit the bioreactor at the site, he said. It is sandwiched between a telecommunications line, a tile line and the ditch buffer.

Twenty-six acres will drain through the bioreactor, with an overflow to be sure not to restrict drainage. The field was first tiled in November 2009, Dittrich said. The tile water is managed by three water gates and a control structure. The water gates are manufactured by Agri Drain Corporation of Adair, Iowa.

The water gates are fully automatic and float operated, according to company literature. They are completed buried. The gates maintain a one foot increase in water elevation between the downstream side of the valve and the upstream side, according to the literature.

Dittrich describes the bioreactor as a bathtub with the water coming in at about the same height as where it's going out. The water is in an eight-inch tile line throughout the bioreactor, kind of like a ring around the bathtub.

The MDA, Agricultural Drainage Management Coalition, Waseca County NRCS and SWCD, the Blue Earch County SWCD and the MPCA all cooperated on the project. Private contractors also provided services.

The next step will be to secure funding to monitor the water coming out of the bioreactor. Dittrich hopes to apply for funding through the 3/8ths amendment.