Keep nitrates in the soil and out of the stream by installing a practice called a saturated buffer as part of the tile drainage outlet.
Jim Jordahl is the program and operations director for the Iowa Agriculture Water Alliance. He says saturated buffers are installed at the tile line near a stream, and new tile lines are placed parallel to the stream. The water flow is then diverted to the new lateral tile lines.
"These lines are perforated, and that flow goes through the soil slowly and through the vegetative area back toward the stream," says Jordahl. "And the idea is that we can remove the nitrate that’s in that tile flow by being taken up into the plants that are in that riparian area, or just the actions of bacteria can turn that nitrate into a harmless nitrogen gas."
Like most edge-of-field conservation practices, the area has to meet specific criteria before a saturated buffer can be installed. It doesn’t bring a direct economic benefit to the landowner, but it’s still advantageous.
"The bulk of the benefit really goes to the end users downstream," he says. "Because of that, we have a number of financial assistance or cost share type programs that can defray most if not all of the cost for these practices. So, farmers and landowners that just want to be proactive and do all they can and stay on the cutting edge of these kinds of practices."
Jordahl says saturated buffers remove a lot of nitrate, are low maintenance, relatively simple to install, and low cost.