Taking on the challenge of improving water quality and reducing soil erosion is nothing new for Randy and Carol Miller. It’s been the Miller’s guiding philosophy since they started farming full time in northern Polk County back in the 1970s.
Over the years the Polk County Farm Bureau members have planted buffer strips along creeks and installed grass waterways. They have adopted a conservation tillage system to reduce soil erosion. And they have reworked their fertilization program to feed the plants at the right time and reduce nutrient losses.
"I guess our philosophy is that we want to improve the water quality as much as possible and do everything we can to reduce soil erosion," Randy said. "We want to keep the soil on our farm and improve the water quality. It just makes sense to us."
So, when the Millers decided to update old and ineffective tiling on a field near Elkhart, they knew they wanted to find a way to improve the quality of water leaving the tile.
Randy, along with their son, Dennis, who farms with them, got the idea to install a bioreactor while attending a drainage workshop put on by Iowa State University (ISU) in Nashua.
Following the workshop, the Millers studied a lot of literature on conservation structures, and consulted with local conservation officials to determine the best placement and size of the bioreactor on their field.
The right thing to do
"After a while we just knew it was the right thing to do," Randy said about the bioreactor. "We wanted to reduce our nutrient loss and help the environment and this seems like the best way to do it."
The Miller also met Jacob Handsaker, Iowa Farm Bureau Federation Young Farmer Committee chair, at the Nashua workshop. They hired him to tile the field, and to build the bioreactor.
With the tiling completed, Handsaker is in the process of digging a 25-foot-wide by 100-foot-long trench at the end of the tile line to create the bioreactor. The trench will be filled with wood chips to create the de-nitrification process.
As water from the tile flows through the bioreactor, the wood chips will convert nitrate in drainage water to nitrogen gas which will dissipate into the atmosphere. Research by ISU and others has shown that bioreactors are very effective at removing nitrate from tile water, with removal rates typically more than 40 percent.
A long process
Planning and installing the bioreactor has not been simple or quick, Carol Miller noted. Over the past several months, the Millers worked closely with the local office of the U.S. Department of Agriculture’s (USDA) Natural Resources Conservation Service and others to design the bioreactor for their field.
"All of these things are really new, so everyone is kind of getting up to speed on it," Carol said.
The Millers had originally hoped to install a saturated buffer on their field, in addition to the bioreactor. A saturated buffer, developed by ISU and USDA researchers working in Ames, diverts a portion of tile drainage water into riparian buffer to remove nitrates.
However, changes in the landscape by neighboring landowners meant that a saturated buffer would not work on the Millers’ field near Elkhart.
Still, the Millers remain very interested in the saturated buffer technology, and hope find a way to employ it in the future.
As they have added more conservation practices to their own farm, the Millers have seen steady growth in the awareness of water quality and conservation among central Iowa farmers.
"There are just a lot of farmers doing these things now," Randy said of the conservation and water quality work. "Everyone is doing something a little different, because what works for one farm may not be right at all for another one."
It’s important that farmers have the options, Carol added. "We need a lot of different options so you can choose what works, like we did," she said. "It would be far less effective if farmers were locked into regulations that prescribe conservation practices for every farm."