Iowa State professor eyes reduction in Corn Belt's nitrogen runoff

Farmers can reduce levels of nitrogen runoff flowing into the Mississippi River by increasing levels of perennial bioenergy grasses.
Farmers can reduce levels of nitrogen runoff flowing into the Mississippi River by increasing levels of perennial bioenergy grasses. | File photo

A recent study led by an Iowa State University agronomist shows that the Corn Belt can reduce levels of nitrogen runoff flowing into the Mississippi River and Gulf of Mexico by increasing levels of perennial bioenergy grasses.

“This study adds to the portfolio of evidence that perennials can be a major part of the solution to nutrient runoff,” ISU Assistant Professor of Agronomy Andy VanLoocke, one of the study’s co-authors, said. “This is a process that we’ll continue to refine, but it adds to the conversation.”

Nutrient runoff, including nitrogen and phosphorus, into the Gulf of Mexico has created a hypoxic, or low-oxygen zone, that cannot fully support an aquatic ecosystem, leading to dead zones. Using computer models, VanLoocke looked at how various levels of perennial grasses can impact nutrient runoff, finding that the perennials could reduce runoff by more than 70 percent. 

“The new research shows that a perennial market would have positive effects on water quality,” VanLoocke said. “With this model in place, we’ll be able to play with more scenarios and land-use practices. Our goal is to give as much information as possible about what’s possible with the landscape.”

The study was published in Global Change Biology Bioenergy, a peer-reviewed academic journal.