Are Nutrient Management Plans Working? Here’s What the Latest Water Quality Data Shows

As a sixth-generation farmer, Jeff O’Connor has seen his family farm change through the generations. The one common thread is a love of taking care of the land. 

“I can’t tell you how many times I’ve heard my family say, ‘Take care of the land, and it’ll take care of you,’” the Kankakee, Illinois, farmer said. “It’s made it easier for me to look at different ways to take care of the land as we learn more about the science behind what goes on in the soil.”

Bringing science to actionable and practical insights to reduce nutrient runoff has been the task of a multi-state effort, developed in response to the U.S. Environmental Protection Agency’s (EPA) 2008 Gulf Hypoxia Action Plan. The plan called for 12 states in the Mississippi, Atchafalaya, and Ohio River basins to reduce the amount of nitrogen and phosphorus in their rivers making their way to the Gulf of Mexico, also known as the Gulf of America, where they contribute to the hypoxia or dead zone. “It’s a voluntary initiative,” explained Laura Gentry, director of water quality science at IL Corn. “States were given a couple of directives, but the main one was to reduce nitrogen and phosphorus losses by 45% by 2035.” 

Nutrient loads in the water have impacts locally as well, said Matt Helmers, a professor of agricultural and biosystems engineering at Iowa State University (ISU). “Local water quality is a concern too,” he said. “Some communities have trouble meeting the drinking water standard for nitrate, and phosphorus can promote algae growth in our streams and lakes.” 

Most of the land in Midwestern states is used for agriculture, and agriculture is the primary non-point source for nutrients entering streams, Helmers explained. “It’s not necessarily from mismanagement of those nutrients,” he said. “If we get rainfall at the wrong times, we see water leave our fields, and nutrients with it. Our corn and soybean cropping is a leaky system, and we have to implement practices to reduce those leaks.”

Are Plans Working? 

Illinois 

The Illinois Nutrient Loss Reduction Strategy (NLRS) had an interim goal of a 25% reduction in phosphorus and a 15% reduction in nitrogen loss by 2025. The most recent biennial report, in 2023, shows Illinois is seeing an increase in the five-year average of total phosphorus and nitrate-nitrogen losses, said Andrew Margenot, soil science professor at the University of Illinois in Urbana. “[From 2017–2021], the average annual load of nitrate went up 4%, and total phosphorus increased by 35% over the baseline,” he explained. “That’s not a great place to be, until you realize how much rainfall we got.” 

According to the 2023 NLRS report, river flow, or water yield, over the same period was 23% higher than the baseline. “The amount of nutrients we lose, especially nitrate-nitrogen, is strongly influenced by how much rainfall moves through the system,” Margenot said. “This is important because farmers can be doing all the right things, but if it rains more, we’re going to see more nitrate.”

When rates are normalized for flow, factoring in rainfall, Illinois showed a reduction in relation to the increase in precipitation. “Is it where we want to be?” Margenot questioned. “It’s not. But I’d say we’re moving in the right direction.” 

When it comes to phosphorus (P), it’s more complicated. Margenot explained that P is lost mostly as sediment: soil particles with phosphorus bound to them. As sediments enter waterways, they slowly migrate downstream; this is called the legacy effect of P losses. “What it means is that sediment that was lost carrying phosphorus, even as far back as a century ago, is still in circulation in our streams,” he said. 

Illinois’ phosphorus loss increase is a prime example of the legacy P effect. Research in Illinois shows that farmers have not been applying P over the amount that was taken off with harvesting crops since 1990, Margenot explained. “There’s evidence that more P is coming out of the state’s croplands than is going on as fertilizer, yet we see a 35% increase in P losses over baseline as the latest five-year average,” he said. Legacy P could explain this sudden increase. “This is a big challenge because it means farmers can do everything right and we may still see P increases because of sediments eroded 50 or more years ago.”

Understanding other non-point sources of phosphorus, such as streambank erosion, is important to solving the problem, said Courtney Briggs, president of the Agricultural Nutrient Policy Council. “We can implement best management practices on every single farm and we’re still not going to see the outcomes we want, unless we really look at this holistically and understand every source,” she said.

Indiana

Indiana has focused on the promotion and adoption of farmer practices and set goals around those rather than track specific water quality targets, explained Ben Wicker, executive director of the Indiana Agriculture Nutrient Alliance. “In the past, we have not had a good dataset that has shown what our contribution is, and a good way to track water quality reduction,” he said. “One of the other challenges in tying goals specifically to water quality is we’re always going to have an extended lag time between practice adoption and those water quality improvements, as well as the overall complexity of these systems.” 

Indiana’s focus regarding agriculture has been farmer attitudes and practice adoption rates for solutions including soil sampling, farm plans for nutrient management, cover crops, no-till, and timing of nutrient applications, Wicker explained. Surveys in 2023 showed gains in adoption for each of these areas compared with 2014. 

“This is going to be a story of continuous adaptation and continuous improvement,” Wicker said. “Regardless of the overall number or percentage acres, I think every farmer needs to take a look at how they’re utilizing nutrients, what practices they’re implementing on their farm, and understand how to be productive and profitable into the future, knowing that there will continue to be economic pressures, as well as these environmental pressures.”

Iowa

“Progress measurement is a big priority of ours,” said Ben Gleason, executive director of the Iowa Nutrient Research and Education Council (INREC). This has been accomplished using ag retailer sales data and farm records to track progress on practices such as crop rotation, cover crops, nutrient application methods and timing, tillage practices, and manure use. 

According to INREC survey results, Iowa has seen an increase of cover crops from nearly 1.6 million acres in 2017 to over 3.8 million acres in 2023. In 2023, 63% of Iowa cropland acres are using no-till or conservation tillage. And the INREC survey’s seven-year average shows 92.4% of phosphorus applications are made only at or below optimum soil test levels.

“Looking at our survey results and the in-field practices, I would say we are making progress,” Gleason said. “We have a lot of work to do to reach our ultimate goals, and it’ll include both in-field and edge-of-field practices.”

Taking Action to Reduce Losses

With myriad conservation strategies available, ISU’s Helmers encourages farmers to be proactive in being part of the solution to reduce downstream nutrient delivery. 

In-Field Strategies

Nutrient management, no-till, and cover crops have helped make a difference on Michael Ganschow’s central Illinois farm, where he raises 2,700 acres of corn, soybeans, and wheat. 

Ganschow said he has found banding his fertilizer and strip-tillage help maximize his efficiency, as well as prevent runoff and erosion from his rolling ground and lighter soils. “The last thing we want to do is spend money on fertilizer and lose it,” Ganschow said.

Near Kankakee, O’Connor has found cover crops to be important not only for the soil health benefits but also nutrient loss reductions. When his local water company compared water samples over the spring season on similar fields, one with cover crops, and one without, the results took O’Connor by surprise. “We were seeing reductions in nitrate loss of 60%–70% with cover crops,” he said. 

Cover crops cost money and introduce risk for a yield drag, according to the University of Illinois’ Margenot. “When it comes to nitrate loss reductions, cover crops are the best thing we can do,” he said. “But we have to balance the risks with the benefits.” 

No-till soybeans have been O’Connor’s standard for 25 years, and in corn since 2013. His interest in no-till was initially to reduce expenses. “It requires less fuel, less wear and tear, and results in less erosion,” he said.

Edge-of-Field Strategies

For fields where nutrient loads are still high despite in-field strategies, edge-of-field solutions, including saturated buffers, bioreactors, and wetlands, can help capture water as it leaves the field and treat it before it’s released, Helmers said. “Even when we do the best job in the field, we still lose some nitrate,” he said. “Edge-of-field practices help further reduce the nutrients that are lost.”

Ganschow uses several edge-of-field techniques on his farm, including a bioreactor that treats tile effluent. A bioreactor uses a wood-chip-filled trench to filter nitrate out of water from tile. To properly size the bioreactor, it’s important to know what the drainage area is, Ganschow explained. Space can be a challenge with edge-of-field practices. His bioreactor treats 17 acres and is 15 feet wide by 30 feet long. Larger fields require more space to be effective. 

O’Connor has used CRP pollinator habitat and buffers to filter water from field edges and reduce nitrate loss. In addition to the nutrient runoff benefits, the pollinator habitat adds a bit of beauty to his community in summer, as well as habitat for pheasants. “There can be value beyond just what the dollars are for the program itself,” O’Connor said.

It’s Voluntary…for Now

“I think over the last 15 years, we have seen a lot of successes,” the Agricultural Nutrient Policy Council’s Briggs said. “We should celebrate the progress that’s been made because it’s significant, but no one is waving any victory flags. There’s more work to be done, and this work is difficult.”

Continuing to show improvement and gains is important, said Wicker of the Indiana Agriculture Nutrient Alliance. Regardless of whether it’s the Gulf of Mexico or a local stream, when questions come about the source of nutrients, each entity will be asked what is being done to improve nutrient loss efficiency. “We need to make sure that within ag, we have our practices and our continuous improvement as a good sound defense for why we do things the way we do,” he said.

The level of implementation needed in Iowa, as well as other states, to meet the Hypoxia Task Force goal far exceeds current levels of implementation, Helmers said. “It’s not going to be easy, but we’re all in this together, and we all need to be part of implementing these solutions.”