Kansas State University

K-State researchers receive nearly $1 million to study carbon cycle science in tallgrass prairie

Submitted by Division of Biology

Kansas State University researchers in the Division of Biology recently received a $998,261 award from the Office of Biological and Environmental Research in the Department of Energy to dig deeper into the impacts of landscape change and drought on carbon storage in grasslands.

The project, "Using root and soil traits to forecast woody encroachment dynamics in mesic grassland," is led by Jesse Nippert, associate professor of biology, with Lydia Zeglin, assistant professor of biology, and collaborators Kate McCulloh, assistant professor at the University of Wisconsin-Madison, and Kevin Wilcox, assistant professor at the University of Wyoming.

"Soil contains plant roots, microbes, water and a large amount of carbon originating from dead plants and microbes, from the surface to a meter or more deep," Zeglin said. "Plant root growth brings new carbon into the soil, and stimulates microbial decomposition activity. If decomposition proceeds all the way to carbon dioxide, carbon is released back into the atmosphere."

As woody plants are increasing in many Kansas grasslands, they could add more carbon to subsurface soil or stimulate microbial activity that depletes existing carbon stocks. The new study will identify changes in soil carbon pools in grasslands as a consequence of increased woody plant growth and increased drought frequency and intensity.

"Low water availability also affects the amount and structure of root growth, and decomposition activity, and thus the distribution of carbon inputs to the soil," Nippert said. "Shrub encroachment and drought happen concurrently, making it a particular challenge to predict changes in the net ecosystem carbon balance."

This project will use rainfall exclusion experiments at the Konza Prairie Biological Station as a platform for data collection. Nippert and colleagues will perform detailed investigations of root and soil traits at varying soil depths, to capture the varying dynamics of grasses and shrubs, and the impacts of frequent drought. The data will then be used to model the carbon balance of grasslands, including the new information on the relationship between shrub encroachment, drought and carbon cycling. The details of these coupled plant-soil-microbial interactions will improve the representation of subsurface processes in Earth System Models and bring greater clarity to forecasts of dynamic changes in ecosystem structure in grasslands and rangelands, in the Flint Hills and beyond.

More information on the funding program, objectives and the list of funded projects can be found online.