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Conservation in action

By Staff | Apr 15, 2016

DURING AN APRIL 11 visit to Greene County, Gov. Terry Branstad learned how this bioreactor, which was installed in 2008 on Mike and Kathy Bravard’s farm north of Jefferson, helps reduce nitrates.

JEFFERSON – It doesn’t look like much. Just a simple metal box standing in a filter strip in Mike Bravard’s Greene County farm field. All eyes were on this humble bioreactor, however, when Gov. Terry Branstad toured Bravard’s farm on April 11.

“As the governor of Iowa, it’s important to be informed about agriculture,” said Branstad, as the sound of water flowing into the bioreactor was overpowered by blustery spring winds whipping across the countryside. “I’m proud that we’ve made water quality a top priority.”

A denitrifying bioreactor like the one on the Bravard farm is essentially a buried trench filled with a carbon source (commonly wood chips) through which tile water is allowed to flow. Microorganisms colonize on this carbon source.

Using wood chips as a food source, the microorganisms begin breaking down nitrate in the water and expelling the nitrate as dinitrogen gas, a primary atmospheric component.

During his Greene County visit, Branstad learned that across Iowa there are 40 bioreactors, including this one installed in Bravard’s field in 2008. While the bioreactors’ contribution to nitrate reduction varies with annual precipitation patterns, they can reduce nitrate loads up to 60 percent.

GOV. TERRY BRANSTAD, left, visits with Greene County farmer Mike Bravard about the merits of conservation drainage, which is described in this booklet from the Iowa Soybean Association.

“Clean drinking water ranks high on our priority list, along with providing safe, economical food,” said Bravard, who also uses conservation tillage, nitrogen stabilizers, cover crops, terraces, riparian buffers and grass waterways to protect water quality and soil health. “We want to share in the solution to improving water quality by experimenting with multiple conservation efforts.”

Following Branstad’s visit to Greene County, members of the Iowa House spent two hours publicly debating the proper way to finance and monitor new, state-sponsored water quality initiatives. On a 65-33 vote, the Iowa House passed HF 2451, which would provide $478 million over 13 years to water quality projects from a water metering tax and the gambling-funded state infrastructure account.

Iowa Secretary of Agriculture Bill Northey commended the Iowa House for recognizing the need for significant, long-term funding for water quality.

“This bipartisan funding plan will allow us to accelerate efforts to address water quality issues on our farms and in our cities,” said Northey. He thanked Branstad for his leadership with long-term water quality funding. “We have a significant need for more infrastructure focused on water quality to achieve the aggressive goals for water quality that we all share.”

The bill now goes to the Iowa Senate where it faces an uncertain future in its current form. Senate Majority Leader Mike Gronstal has indicated Democrats will unveil their own approach to addressing the state’s water quality challenges.

Other lawmakers are bringing a unique perspective to the water quality debate. Rep. Mike Sexton, R-Rockwell City, said it would be wise to re-evaluate whether 10 parts per million, the current safe drinking water limit for nitrate, is the correct level, or whether it’s an unnecessarily low threshold. “It’s time we take a serious look at this,” said Sexton, who farms in Calhoun County and toured the Bravard farm with Branstad.


In the meantime, farmers like Bravard are continuing to invest in conservation tools to protect Iowa’s water quality. On the farm where his bioreactor is located, approximately 46 acres are drained into the system, which is designed to filter nitrates from water runoff before the water enters a nearby stream that empties into West Buttrick Creek, a tributary of the Raccoon River.

Bioreactors have no adverse effects on crop production and are designed so they don’t restrict drainage. A control structure determines the amount of tile flow that is diverted into a bioreactor.

During periods of high flow, excess water bypasses the bioreactor and continues to flow through the existing field tile.

Bravard’s bioreactor includes a 25-by-50-foot pit, 6 feet deep, with a 5-foot layer of wood chips, with 1 foot of soil covering it. When this bioreactor was installed in 2008, it was the largest known bioreactor in the United States.

Today, many bioreactors can handle tile water from 100 acres or more. A typical bioreactor installation costs $8,000 to $12,000, although the cost will vary with the bioreactor’s size, according to the Iowa Soybean Association. There is no one-size-fits-all solution when it comes to conservation, noted Bravard, a third-generation farmer who received the ISA’s Environmental Stewardship Award in 2016. “What works well on our farm may not be the best solution for other farms, due to the layout of the land, soil types and other factors.”

Working together

A willingness to try new things is the key, said Roy Bardole, who farms with his family near Rippey. “There are lots of the good kind [of farmers] in Greene County who are trying to see how cover crops and other options fit together to reach conservation goals.”

Conservation isn’t free, however. “Farmers make a significant investment in conservation practices,” Bardole said. “Also, Mother Nature is always in control, so implementing new conservations practices is a learning experience.”

Bravard and wife, Kathy, and their four children plan to continue partnering with the ISA and other specialists to improve environmental stewardship on their farm every day.

“It’s important to always focus on the long-term goals of why farmers are good stewards of the land,” Bravard said. “We want to leave the land in better shape for future farmers to succeed and continue a legacy of love and respect for the land.”

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