On a warm summer evening in July, landowners, farmers, and community citizens gathered together at Iowa State’s Field Extension Education Laboratory to learn what they can about the benefits and a little science behind denitrifying bioreactors. A denitrifying bioreactor is a subsurface trench at the edge of a field usually filled with hardwood chips, installed to reduce nitrate concentration in the tile water that it diverts. The wood chips are the carbon source that contains the bacteria needed to breakdown the nitrates in the water to convert into nitrogen gas.
The participants were able to see a bioreactor in action and heard from Iowa Learning Farms expert, Liz Juchems about the benefits to having a bioreactor and how it can help in the effort to improving water quality. She explained that using bioreactors alone in the state in all of the identified appropriate areas would reduce the nitrates that end up in our waterways by 43%, which exceeds the 41% goal of the Iowa Nutrient Reduction Strategy.
Jace Klein, agriculture engineering technician, spoke about the process of designing and implementing a bioreactor, “Tricky part of bioreactor installation is finding the tile outlet. Good tile maps are the unicorn of the Midwest.” Klein also went on to explain that bioreactors can remove up to 90% of the nitrates in the water but in cases of large amounts of rain, the water will bypass and the bioreactor will only treat around 50% of the total water.
Local landowner, Joe Reutter, spoke about his experience with the bioreactor that was implemented 8 months ago in Boone County. Results showed inflow of water at 15 ppm (milligrams per liter) and outflow of water at 3 ppm (milligrams per liter). That is an 80% reduction of nitrates! Joe took advantage of one of the cost-share opportunities provided by Prairie Rivers of Iowa among the others that we offer!
Every conservation practice we implement is another step in the right direction to build soil health and is slowly but surely improving water quality not only in our local streams, but the entire South Skunk Watershed and beyond!