Taking a one-water approach

WEBSTER CITY – When it comes to Iowa’s water quality, one thing is clear – farmers are finding new solutions to protect this precious resource.

The Iowa Soybean Association showcased these efforts during a recent Environmental Discovery Tour in north-central Iowa.

“Managing nitrogen, controlling erosion and protecting water quality are important to all of us,” said Arlo Van Diest, who has farmed in the Webster City area for 50 years and hosted tour guests at one of his fields.

Van Diest is a pioneer in strip-tillage for one-pass fertilizer application and planting, having bought his first strip-till machine in 2001. He told the 45 participants, including state lawmakers and other rural and urban leaders, that his soils are now in better shape, his corn and soybeans establish better roots and the crops yield as well or better than crop in no-till or conventional tillage systems.

“I’ve also worked with the ISA through their environmental programs and On-Farm Network to study the right amount of nutrient application rates for our fields,” said Van Diest, whose family manages approximately 2,300 acres of cropland and incorporates cover crops to protect soil and water quality.

“We’ve voluntarily reduced fertilizer rates, wherever feasible,” he said.

ISA hosted its event on Oct. 24 to offer a first-hand look at conservation practices in action.

“We want to create opportunities for both rural and urban folks to see what’s going on in Iowa’s watersheds and talk to the farmers who are invested in these issues,” said Roger Wolf, ISA’s director of environmental programs and services.


Farmers showed that there’s a lot going on in their fields to protect water quality. Tim Smith, who farms near Eagle Grove, explained the various conservation practices he’s using on his 850-acre farm, including 25 acres he has enrolled in the Conservation Reserve Program.

In 2011, Smith and his wife, Lana, began participating in the Upper Mississippi River Basin Initiative program through the Natural Resources Conservation Service.

On 320 acres located in the Boone River watershed, the Smiths have planted cereal rye cover crops, use strip-till and implement various nutrient management practices.

“A lot of people are watching agriculture today,” Smith said. “The tools and the science are available to help farmers protect water quality, and there are a lot of groups like ISA that can help you get started.”

The Smiths, who have received an Iowa Farm Environmental Leader award from the Iowa Department of Natural Resources, have also installed a bioreactor on tile drainage lines from one field to reduce nitrates.

Van Diest has also installed a bioreactor on one of his fields near Webster City and has used it as an edge-of-field drainage water treatment system for five years.

Bioreactors sound complicated but work on a simple principle, said Keegan Kult, ISA’s environmental project manager. With a typical bioreactor, a trench is dug and filled with wood chips, covered with geo-textile fabric and topped with soil. In Van Diest’s field, the bioreactor comes off the field’s 8-inch tile lines.

Drainage water is routed into a bioreactor through an inflow water control structure. Bacteria living in the soil and wood chips use nitrate for respiration in the anaerobic conditions.

An outflow water control structure keeps the water in the bioreactor long enough for the bacteria to remove nitrate before the water flows away.

Control structures can by-pass the bioreactor during high-flow events.

“Bioreactors offer a proven method for denitrification,” said Kult, who noted that a bioreactor can lead to a 40 to 60 percent reduction in nitrates from a field, in addition to reducing phosphorus levels.

Bioreactors usually cost $8,000 to $12,000, and have a lifespan of 12 to 15 years, he said.

State Rep. Dave Deyoe, R.-Nevada, said he had not seen a bioreactor before and was impressed with the technology.

“I think everyone is interested in what we can do to improve water quality in Iowa, Deyoe said. “As a member of both the ag and environmental protection committees, I wanted to see how the state’s new water quality initiative is being implemented.

“I commend the ISA for stepping up to the plate and leading on environmental and conservation issues through the programs they are offering farmers.”

Finding solutions

Deyoe and other tour participants also learned more about how an oxbow in a pasture is protecting water in White Fox Creek in Hamilton County.

An oxbow is a meander of a river or stream that has been cut off from the present flow as the stream channel has migrated within its floodplain.

“An oxbow functions kind of like a little wetland and offers the potential for innovative tile line nitrate treatment practices,” said Kult, who noted that the ISA is working with the Nature Conservancy to study oxbows’ roles in environmental protection.

“Oxbows also offer habitat for fish and wildlife,” he said.

Farmers and groups like ISA are also looking beyond Iowa’s creeks and farm fields to collaborate with urban leaders to addresses water quality management in the state.

ISA works closely with groups like the Iowa League of Cities to keep the lines of communication open.

“We don’t want to make folks on the land the enemy,” said Dustin Miller, ILC’s governmental affairs manager, who participated in a panel discussion during the ISA’s tour. “That’s not a winning strategy to advance clean water.”

Collaborating and studying new solutions is the way to strike a balance between maximizing production agriculture while protecting natural resources, Wolf said.