Despite Conservation Changes, Iowa Sends More Nitrates Downriver

Iowa is a leading contributor to the so-called dead zone in the Gulf of Mexico. The low-oxygen area the size of Connecticut can kill fish and sea life. And it’s largely fueled by the runoff from Midwestern farm fields. Five years after the state created a plan to slow this process, researchers say Iowa isn't moving fast enough to cut its nutrient runoff.

Rob Stout is proud of the native plants he's growing on his farm near the West Fork of the Crooked Creek in Southeast Iowa. A keen observer can spot a monarch butterfly caterpillar clinging to the grasses. Red-winged blackbirds fly low.

“There’s some purple coneflower, some pale cornflower. Bee balm over there, with the purple," Stout pointed out. "You come out here and if it’s quiet and not windy, it is just abuzz with bees. Bees and little critters.”

Stout farms 1,100 acres in Washington County: half corn and half soybeans. He also has 9,000 hogs. And he’s one of a handful of farmers that’s taking steps to cut the amount of runoff from his fields.

Nitrogen and phosphorous from fertilizers flow downstream, where the nutrients spur algae growth, potentially poison drinking water, and starve sea life in the Gulf of Mexico, including commercial fish and shrimp populations. 

Underneath the prairie grasses and wildflowers on Stout's farm is one of his recent additions, called a bioreactor. It’s more or less a large underground pit of woodchips. But it cost $14,000, half of which Stout paid. A state grant for conservation practices picked up the other half.

“It was almost $5,000 worth of woodchips,” Stout explained.

The woodchips filter nitrogen out of the water that runs under the fields through underground pipes called tiles. This bioreactor treats runoff from approximately 67 of Stout's 1,100 acres. It's a fraction of his land, but he's been impressed with the results.

The Iowa Soybean Association routinely tests Stout’s water. And the results vary, but he said the bioreactor can remove 50 percent, and as much as 90 percent of the nitrates from the water that passes through it.

“Out of the bioreactor, it’s always been under 10 parts per million, which is the drinking water standard," Stout said. "In fact the last one I saw was under 1 part per million.”

But the bioreactor is only one part of Stout’s system. He doesn’t till his land, and he grows cover crops, both of which can reduce erosion and boost microbial activity, keeping valuable, nutrient-rich soil on the landscape and out of the waterways. And he’s also worked with other farmers across the West Fork Crooked Creek Watershed to build terraces, and establish wetlands, ponds and native plants, all of which scientists believe reduce nutrient runoff.

“I want to see other people do it, too. I don’t want to be just an island here. And I’m not. But I’d like everybody do it. Everybody to be no-tilling and using cover crops and doing the best job of conservation we can," Stout said. "It’s good for everybody.”

This kind of personal investment, multi-pronged approach and collaboration is what state officials want to see. Five years ago, Iowa implemented a statewide Nutrient Reduction Strategy, with goals to cut the state’s runoff by 45 percent. 

But the strategy is voluntary; farmers don't have to adopt conservation practices. And recent research shows what Stout and people like him are doing, is not enough.

University of Iowa research engineer Chris Jones recently reviewed the state’s nutrient runoff data from 1999 to 2016. His analysis shows during that timeframe Iowa sent disproportionate amounts of nitrates downstream, relative to its land size and water usage.

“We determined that nitrate loadings here in Iowa had increased about 40 to 50 percent,” Jones said.

According to Jones' research, on average Iowa is responsible for 29 percent of the nitrate load in the Mississippi-Atchafalaya Basin; 45 percent of the load in the Upper Mississippi Basin (north of the confluence with the Missouri); and 55 percent of the load in the Missouri River.

While agricultural runoff from other states and wastewater runoff from municipal areas is also a factor, Jones said there is a direct connection to the scale of corn and soybean production.

“It’s so much more observable here because we have so many acres in corn and soybean production,” Jones said.

One factor that sets Iowa apart from other Corn Belt states in the magnitude of ecological transformation of the landscape. What was largely a prairie ecosystem some 200 years ago, with thousands of plants and animals and natural processes for filtering and cycling water, is now largely "working land", much of it devoted to growing two species: corn and soybeans. 

Ecologist and author Connie Mutel said the prairie ecosystem processed water differently, forming bogs, fens and marshes with grassroots reaching deep into the ground, sometimes as much as 20 feet. Mutel explained how water moves through Iowa's landscape has fundamentally changed.

"And so the water largely falls on those compacted, hardened soils and runs off into adjacent waterways. Because of the large quantities running into the waterways, those waterways are actually human creations," Mutel explained. "They're not natural."

Those waterways "continue to erode greatly and carry not only large quantities of sediment, the soil itself, but also the pollutants down into adjacent rivers, and from there into the Mississippi and into the Gulf of Mexico," she said.

In order to reduce nutrient runoff, the challenge then for researchers, policymakers, producers and landowners is to simulate some of the natural processes that were a part of the prairie ecosystem.  

Jones said there’s no question that conservation practices reduce nutrient runoff. But there aren’t always clear benefits for farmers. While some approaches like cover crops can reduce erosion and improve soil health, some farmers report they can adversely affect yields the next year. Putting in ponds, wetlands, prairie strips or bioreactors often means more work and added costs.

Still, Iowa Agriculture Secretary Mike Naig said more farmers are getting involved in what he sees as a long-term approach.

“Last year we had 1,000 first-time users of cover crops who participated in our cost-share program," Naig said. "So even in a tough economy, ag economy, we are still seeing folks willing to invest and try.”

But critics have said the adotion of conservation practices is not happening fast enough. A recent survey from Iowa State University showed just 4 percent of the state’s farmland has cover crops. And only 20 percent of farmland owners were willing to pay into conservation-related planting costs.

Research backs up the efficacy of approaches like bioreactors, wetlands, prairie strips and others. Chris Jones said now it's a matter of galvanizing the public support and funding necessary to enact system-wide change.

“At this point it’s not really a scientific problem," Jones said. "It’s a socio-economic question.”

Looking out over a soybean field on his Washington County farm, Rob Stout estimated he spends an extra $17 an acre on planting cover crops. For him that tallies out to around about $18,000 a year. Stout said he sees it as a worthwhile and longterm investment in soil health and productivity. Underneath Stout's feet, microbes are actively breaking down last winter's cover crop of cereal rye, churning it into fuel for this year's soybeans.

But a time when median farm income is falling and debts are growing, conservation is not a priority for a lot of farmers.

“It’s fear of change. One more added step. People are busy. Crop margins are really, really tight right now. The prices of corn and beans aren’t good," Stout said. "They think, one more expense. What’s another 17 bucks an acre then? And I’m hardly breaking even or losing money?” 

Naig says between public and private funding, $420 million went towards water quality conservation in Iowa in 2017. But researchers say this is a multi-billion dollar problem. It’s not clear if that amount of money will ever come.