Leopold Center for Sustainable Agriculture

Grazing and fire as management tools

Back to Leopold Letter Winter 2009

By ALLISON SEVERSON, Communications Assistant

Where there’s smoke, there’s fire — and in Iowa fire seldom is viewed as positive, even on the southern Iowa expanses of the Grand River Grasslands.

The Patch-Burn Grazing Team, an Iowa State University restoration ecology team whose work is funded in part by the Leopold Center’s Ecology Initiative, is working to change that perception. Team members are looking at both the promise and the practice for adoption of a grasslands management technique called patch-burn grazing.

The site for their work is the Grand River Grasslands Conservation Opportunity Area, a 70,000-acre tallgrass prairie restoration landscape that straddles the Iowa-Missouri border. The research includes more than 1,000 acres managed in one of three ways for this project:

  • prescribed fire only,
  • grazing, then burning the entire site once every three years, and
  • burning one-third of the area each year, and allowing access by cows for grazing, referred to as patch-burn grazing or fire-and-grazing interaction.

North American prairie ecosystems evolved in the context of both fire and grazing, but this practice largely has been abandoned as a management tool in recent decades. The team hopes to show nearby landowners the benefits of controlled burning and grazing.

“This project uses a new method of burning called fire-and-grazing interaction, which allows animals to follow the fire that is applied to specific portions of the landscape where the fresh, new, green growth emerges,” said David Engle, a professor in natural resource ecology and management at Oklahoma State University, who began the project while at Iowa State University.

When asked about carbon output from the burning, Engle said research shows that burning grasslands is a carbon-neutral process; released carbon is offset by carbon turnover in the soil. “There is no more sustainable agricultural enterprise than livestock grazing on perennial forage plants,” he added.

Ryan Harr, a scientist in the natural resource ecology and management department at ISU, said the purpose of using fire is to clear the landscape of old vegetation and woody debris. “The result is new vegetation that can be used for cattle production,” he noted.

Iowa grasslands are being threatened by several invasive species. Eastern redcedar spreads at an exponential rate in grasslands that have not been burned in more than a decade. Sericea lespedeza is a noxious weed unpalatable to cattle and can not be controlled by current herbicides.

“Both of these species could be more effectively controlled with patch-burn grazing than with traditional grazing management,” said Lois Wright Morton, sociologist and principal investigator on the project, “but bringing that knowledge into adoption and action is another challenge for our team.” 

Diane Debinski, professor in the department of ecology, evolutionary and organismal biology, is studying insect responses to patch-burn grazing because of their importance as pollinators, for nutrient cycling, as food for songbirds and as predators for crop pests. “We can build a structure that looks like a grassland, but does it act like a grassland?” she asked.

A long-term goal is to develop a framework for implementing the fire-grazing model at several sites under the jurisdiction of the Iowa Department of Natural Resources and the Iowa chapter of The Nature Conservancy. “We would like to develop a model that can be used by any private landowner who wants to use the burning practice,” said Wright Morton.

Leopold Center Ecology Initiative leader Jeri Neal hopes producers will see the practical application of the patch-burn tool to make existing grazing operations more profitable, especially in southern Iowa where they compete with row-crop agriculture.

“Patch-burn grazing seems like a tool that might bridge the gaps between programs and practices on the land,” she said. “This project will help Iowans figure out if we can make this work.”

Back to Leopold Letter Winter 2009