WOOD CHIP BIOREACTORS
Woodchip bioreactors and saturated buffers dominated discussions at a farm field day hosted by the Toquam Family Farm in Dodge County on Friday, June 28.
The Toquam Family Farm is located about seven miles northeast of Blooming Prairie. The Toquam Family Farm spans three generations: Orlo, his son Roger and Roger's three sons, Brennen, Josh and Isaiah. All were present at the field day.
Early in the morning, Roger, a Ripley Township Board member, ironically was closing roads in Ripley Township due to flooding conditions caused by heavy rains the night before.
A host of experts on drainage water management shared experiences with new farm field drainage practices, mainly with woodchip bioreactors and with saturated buffers.
The Toquams were approached by the Dodge County Soil & Water Conservation Board and the Zumbro Watershed District to construct a bioreactor for the purpose of managing drainage water on their properties. Ellingson Companies constructed a wood chip bioreactor on the Toquam property in Ripley Township.
Another reactor is to be constructed on Toquam property located in Westfield Township of Dodge County. This project is in the Cedar River Watershed.
Roger Toquam said his family is interested and concerned about conservation practices, which will make them better stewards of their land.
The Minnesota Natural Resources Conservation Service (NRCS) funded an agreement in August 2018 with Ecosystem Services Exchange (ESE) to increase technical assistance available to producers in the southern portion of the state to reduce nitrate loading of Minnesota watercourses.
This three-year agreement places an emphasis on watersheds draining into the Mississippi River Basin.
The agreement provided for 10 training sessions for NRCS and partner organization staff. The three-year project also includes 210 site reviews, 70 drainage water management plans and designs for 50 saturated buffers and 40 bioreactors.
The morning session and part of the afternoon session centered around presentations from:
• Mark Dittrich, Minnesota Department of Agriculture
• Paul Sweeney, Ecosystem Services Exchange
• Keegan Kult, Agricultural Drainage Management Coalition
• Dave Jones, United States Department of Agriculture Natural Resource Conservatonn Service
• Andry Ranaivoson, University of Minnesota Southwest Research and Outreach Center
• Gary Feyereisen, USDA Agricultural Rsearch Service
• Mike Tveten, Ellingson Drainage
• Ray Thomas, Ellingson Drainage
Later in the afternoon, field day attendees took a tour of the wood chip bioreactor being constructed on the Toquam property in Ripley Township.
Prior to the start of the field day agenda, Paul Sweeney of Ecosystem Services Exchange took time with this writer to explain the various facets of drainage water management.
What is a woodchip bioreactor?
Go to the Internet and learn that bioreactors are essentially subsurface trenches filled with a carbon source, mainly wood chips, through which water is allowed to flow just before leaving the drain to enter a surface water body. The carbon source in the trench serves as a substrate for bacteria that break down the nitrate through denitrification or other biochemical processes.
Organisms from the soil colonize the woodchips. Some of them break down the woodchips into smaller organic particles. Others “eat” the carbon produced by the woodchips, and “breathe” the nitrate from the water. Just as humans breathe in oxygen and breathe out carbon dioxide,
Sweeney says bioreactors reduce nitrate levels leaving a farm field via tile. The bioreactors intercept tile water and direct it into the bioreactor, Sweeney explained.
The biology within the reactor breaks down the nitrate into nitrogen gas, Sweeney further explained. The excess water then leaves the reactor and goes to the stream or ditch, he said.
With a wood chip bioreactor, it is hoped that 40 to 60% reduction in nitrates will be achieved. The objective is to reduce the nitrates going down stream. If the nitrates are not removed, the drinking water standard is exceeded.
Sweeney said that Minnesota Nutrient Reduction Strategy states that 43% of the nitrates leaving Minnesota via the Mississippi River comes from tile drainage.
Sweeney says the reduction of nitrate levels is achieved by employing these practices:
1) Drainage water management
2) Woodchip bioreactors
3) Saturated buffers
Sweeney reports that there is considerable interest in this program from local producers in Steele County and Dodge County. There is no cost to the producers.
Tom Gile of the Board of Water and Soil Resources says that producers must select a farm field practice that will work for them. "Treat the water before it gets into the stream," he said.
These drainage water management practices represent a learning experience, Gile said.
Lunch was served by the Dodge Center Lions Club.
The list of other sponsors of the field day included: Dodge Soil & Water Conservation District, Minnesota Department of Agriculture, Ecosystem Servces Exchange, United States department of Agriculture natural Resources Conservation Service, USDA Agriculture Research Service, Al-Corn, Clean Water Land & Legacy Amendment, University of Minnesota SWROC, Compeer Financial, Dodge County Corn & Soybean Growers, Minnesota Agricultural Water Resource Center, Nutrien Ag Solutions and Claremont Insurance Agency.