Iowa farms using low-tech systems to filter fertilizer-borne nitrates from water

Photo: A worker shovels wood chips in a bioreactor trench in a farm field, on March 28, 2023, near Roland, Iowa. Low-tech systems called bioreactors and streamside buffers help filter nitrates from rainwater before it can reach streams and rivers. (AP Photo/Charlie Neibergall)

Nick Helland’s central Iowa farm looks much like every other nearby farm on this chilly March day, with corn stubble stretching from a gravel road up over a low hill to the northern horizon.

But look closely, and you can see patches of muddy ground where a few months ago crews buried low-tech systems called bioreactors and streamside buffers that filter fertilizer-borne nitrates from water as it drains from Helland’s field into nearby Big Creek and eventually the Des Moines River.

The underground devices work. The question is whether one Iowa county’s promising new approach to an old problem can be expanded enough to finally address nitrate pollution that, for years, has endangered drinking water, made more than half the state’s waterways unfit for fish or humans, and fueled a giant dead zone nearly 1,000 miles away in the Gulf of Mexico.

Polk County is doing it by making it painless for farmers — handling all the logistics and arrangements for the systems — and throwing in payments of $1,000 per site. Installations have exploded in the past two years, to 104, after only a handful were installed the eight years before that.

“They paid me and they paid […]

Full article: Iowa farms using low-tech systems to filter fertilizer-borne nitrates from water