A Kansas State University researcher received a grant to study how prairie animals help the soil.


Lydia Zeglin, microbial ecologist and professor of biology at K-State, received $650,000 from the National Science Foundation's Faculty Early Career Development Program to research interactions between the tallgrass prairie's bison and cattle and soil microbes.


The interactions between grazers and soil microbes are vital for prairie biodiversity and may affect how soil can help provide a remedy for nitrogen pollution.


"We know how important grasslands are for carbon storage, but intact prairie ecosystems are also sponges for nitrogen," Zeglin said. "This is in part because the soil microbes can pick up nitrogen quickly and help keep it in the soil for a long time, even after plant tissue has decomposed."


Plants need nitrogen — a building block of proteins, DNA and other essential molecules — for healthy growth. These microbes help the environment. According to Zeglin, soil microbes keep nitrogen from leaching into the groundwater, streams, rivers and lakes.


"There may be a balance between the plant uptake and the microbial activity that regulates good plant growth versus potential for pollution," Zeglin said. "There's a concept called nitrogen retention, which is sort of the beneficial ecosystem service that we are interested in making sure we are measuring and sustaining."


Zeglin's preliminary research suggests that cattle and bison may provide a service to the ecosystem by helping microbes spread useful nutrients across the prairie.


"Grasslands evolved with bison and other large animals," Zeglin said. "One intriguing consideration is that bison and cattle can move microbes around as they pass across the landscape. They also redistribute nitrogen as they move around, which might help cultivate certain types of soil bacteria and archaea (microorganisms).


“Our plan is to collect samples in a way that enables distinguishing between the two mechanisms."


Feces from livestock, including cattle and bison, help add nutrition to the soil. In addition to carbon sequestration (removing carbon dioxide from the atmosphere), some microbes are beneficial to helping plants grow.


“There is primarily more available nitrogen in digested material than undigested,“ Zeglin said. ”The animals carry microbes through their guts and deposit them elsewhere.“


Zeglin's research will test soil from multiple prairie locations with a citizen scientist approach.


"Our ultimate goal is to understand the nitrogen cycle in all prairie soils better," Zeglin said. "We will be working with The Nature Conservancy, ranchers and students to contribute soil samples from bison- and cattle-grazed areas across the Flint Hills."


According to Zeglin, there is little research examining how the animals’ movement positively affects the soil.


“I’m most intrigued with the ideas of connectivity and dispersal around the prairie landscape,” she said.


During the next five years, Zeglin and her students, including graduate students, will perform detailed investigations of soil microbial diversity and activity to learn whether soil chemistry determines microbial diversity, or vice versa.