When he looks at Elk Run Creek near his family’s farm in northern Carroll County, Brian Hoffman thinks back to how much he enjoyed spending time there as a boy.
“We’d pack a picnic lunch on Sundays and meet up with the neighbor kids to go fishing,” said Hoffman, who raises corn, soybeans and cattle south of Auburn where he grew up with eight siblings. “We always had lots of fun.”
Hoffman never dreamed Elk Run Creek would become a focal point years later with the 2013 debut of the Iowa Nutrient Reduction Strategy, which serves as a guide to reduce nitrogen and phosphorus entering the state’s many waterways by 45 percent.
While Hoffman supports water quality improvements, he was still a bit hesitant when the Iowa Soybean Association (ISA) approached him a few years ago about installing a bioreactor to help remove nitrates from tile lines before the water reaches the creek.
“I was a little leery, because I didn’t know what to expect or whether it would work,” said Hoffman, who is president of the Carroll County Farm Bureau.
Like many farmers, Hoffman was also concerned about the confidentiality of data related to his farming practices.
The more he talked with ISA staff about this unique opportunity, however, the more confident he became, especially since the bioreactor wouldn’t cost him a dime due to cost-share funds. “It was a deal where we couldn’t lose,” he said.
Cutting nitrate levels
It took less than a day to install the $11,800 bioreactor in an area of Hoffman’s cattle pasture along Elk Run Creek. After crews dug a trench and installed a liner, the pit was filled with wood chips comprised of ground-up wood pallets supplied by Koster Grinding near Carroll.
The bioreactor functions like an underground filter. Water from the tile line is redirected into the wood chips, where microbes convert nitrate in the water into nitrogen gas before the water flows into Elk Run Creek.
On average, bioreactors reduce nitrogen leaving the tile drainage by 43 percent, according to the North Raccoon Farm to River Partnership, an Iowa water quality initiative spearheaded by Agriculture’s Clean Water Alliance. Results have been even better with Hoffman’s bioreactor, which is reducing nitrate levels from 40 acres of his 75-acre field near Elk Run Creek.
“This bioreactor has cut nitrate levels by 75 percent,” said Hoffman, a third-generation farmer whose family has farmed this land since the mid-1960s. “I’m amazed.”
Terraces enhance conservation
Hoffman’s willingness to adopt new solutions has inspired other farmers. “We now have three bioreactors in the neighborhood,” said Hoffman, who noted that his bioreactor is projected to last 10 to 15 years before the wood chips need to be replaced.
Hoffman has also invested in in-field practices like grass waterways and terraces to keep soil in place and protect water quality. “While our land is considered to be flat ground around here, I was still having some issues with washouts and gullies After I started adding terraces about five years ago, I couldn’t believe the positive difference, and neither could my landlord.”
When a 9.5-inch rain pounded the area on August 12, 2018, no gullies washed out in the terraced areas. “Without terraces, some fields had 10-foot swaths of washed-out areas,” said Hoffman, who farms with his brother Mark and son, Josh.
There are no drawbacks to the terraces or the bioreactor, said Hoffman, who hopes his family’s land becomes a Century Farm someday. “We’ve got to start somewhere to improve water quality. Our philosophy is to leave things better than we found it.”
Maulsby is a freelance writer in Lake City.