Many new farm practices are being implemented at the Van Zante Creek Water Quality Improvement Project continues north of Pella.
It’s a part of the Iowa Nutrient Reduction Strategy, which aims to reduce the amount of nitrogen and phosphorus entering Iowa’s water bodies by 45 percent. According to Watershed Coordinator Terry McNeely, in-field practices are implemented within an agricultural field and are the first line of defense to minimize the amount of sediment, nutrients and pollutants leaving farm fields by reducing erosion and water runoff. Edge-of-field practices are implemented at an outside edge of a field and serve as a second line of defense to improve water quality by trapping and filtering pollutants leaving the field before they reach the surface waterbody.
A newer edge-of-field practice in Iowa is the bioreactor. A bioreactor is a buried trench filled with a carbon source, commonly wood chips. The wood chips provide a food source for microorganisms. When tile water is diverted into the trench, the microorganisms are able to break down nitrate in the water and release it as harmless nitrogen gas to the atmosphere.
Bioreactors are suitable for many locations and can be installed in conjunction with existing and new tile. Most current bioreactor designs are successful at reducing the amount of nitrate in drainage areas from 30 to 80 acres. To date, most bioreactors in Iowa are about 100 to 120 feet long and 10 to 25 feet wide. Typically, no land is taken out of production for a bioreactor. Because bioreactors tend to have an orientation that is long and narrow, they fit well in edge-of-field buffer strips and grassed areas. The lifespan of a bioreactor is estimated to be 15 to 20 years, after which the woodchips would be replaced to continue effectively treating water.
To learn more about bioreactors or the Van Zante Creek Watershed Project, contact Watershed Coordinator Terry McNeely at 641-842-5314. To learn more about Iowa’s Water Quality Initiative and Nutrient Reduction Strategy, click here.