New Buffers Could Reduce Nitrogen Runoff

Scientists from the University of Illinois have researched a new conservation practice known as saturated buffers and say it could reduce nitrogen from agricultural drainage by 5 to 10 percent.

“It might not sound like much, given that agricultural drainage only represents a portion of the nitrogen getting into the Mississippi. But 5 to 10 percent is pretty good for an inexpensive, passive system that farmers can put in and forget about,” said Reid Christianson from the university who co-authored the study.

Saturated buffers are vegetated strips of land—as little as 30 feet wide—between tile-drained agricultural fields and waterways. Ordinarily, tile pipes carrying drainage water from the fields empty directly into ditches or streams. With a saturated buffer, the water is re-routed to a perforated pipe running below the surface and parallel to the stream. Water then flows through the soil of the saturated buffer into the stream. Along the way, soil microbes naturally remove up to 44 percent of the nitrogen.