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Protecting Water and Soil
In early May, corn is up in a strip-tilled 45-acre field on the farm of Arlo and Claudia Van Diest near Webster City, Iowa. At the edge, water flows from an 8-inch tile outlet into Lower White Fox Creek. Any nitrates that might be in its clear water are invisible. So is a 3-foot-deep trench buried under a grass buffer at the field’s edge. It’s filled with a 10-yard-wide strip of wood chips stretching 126 feet behind the outlet. Microbes living on the wood remove up to 70% of the nitrates that would reach the creek. Van Diest is among a dozen farmers in Iowa trying out new bioreactors.
“They’re kind of an experimental thing, although we know they do work,” he says.
Van Diest has been conservation-minded for decades, trying several ways to lower tillage until he learned about strip-till at the Commodity Classic in 2000. He’s cut nitrogen rates by about 15%.
This year, “all of our corn acres, we’re going to be sidedressing with anhydrous,” says Ryan Davison, Van Diest’s granddaughter’s husband, who now manages 1,200 acres of the 2,300-acre operation.
In recent years, Van Diest has even loaned strip-till equipment to neighbors.
“He has done so much to promote the practice,” says Heath Ellison, agriculture and natural resources manager for the Iowa Soybean Association. ISA has calculated the energy savings of the farm’s switch to strip-till: 2 gallons per acre of diesel fuel equivalent.
The Van Diest farm was a stop on a recent tour of farms organized by the United Soybean Board. It’s part of the USB Confluence Project on watershed management.
Roger Wolf, head of environmental programs for the Iowa Soybean Association, has worked for decades to help improve the Raccoon River watershed, the source of drinking water for more than a tenth of Iowa’s population.
He’s seen progress. A study published in agronomy and soil science journals shows sediment in the river down sharply from a peak in the 1970s.
“We’re proud of the commitment the industry has made,” says Wolf. “Having said that, we’re not saying it’s done. We’ve got a lot of work to do.” ISA is teaming up with other groups on solutions to the vexing challenge of managing nitrogen.
Laura Foell and her family have used no-till on their Schaller, Iowa, farm since 1996. As a USB director, she sees the importance of sustainability – whether she’s convincing Europeans to buy U.S. beans or working with food companies to deliver a product certified as sustainable.
“In the U.S., we’ve had 75 years of conservation laws – since the Dust Bowl,” she says. USDA spot checks are proof of sustainability. Yet, she doesn’t dismiss concerns at water utilities. “As farmers, we are looking at how we can do continuous improvements,” she says.