USU Research Looking At The Root Of Plant-soil Interactions

Oct 16, 2020

Credit Elizabeth Materna, USFWS

To improve restoration and agricultural practices, USU scientists are studying how soil microbes and moisture affect native and nonnative plants.

“In general, plants accumulate bacteria and fungi that eat their roots. Nonnative plants, because they've been introduced from a different ecosystem, they're lacking some of those pests and they can grow really well. It all is happening because of this plant-microbe communication. If we can stop that communication, then you prevent the positive feedbacks for weeds. And so it sort of tips the competitive balance back towards the native plants,” said Andrew Kulmatiski, an associate professor at Utah State University. Kulmatiski studies interactions between plants and the soil they grow in.

Soil microbes play a big part in how well plants grow, and invasive plants use that to their advantage. But, Kulmatiski said, adding activated carbon to the soil can stop unwanted microbe communication in its tracks.

“Activated carbon is like a molecular sponge. It just will hold on to any organic compound. It's like cutting the phone lines. Nobody can talk to each other. And so then you don't get these positive feedbacks for weeds and negative feedbacks for native plants.” Kulmatiski said.

Soil microbes aren’t the end of the story. Kulmatiski said precipitation has a big effect on the soil too, and the plants within it.

“Here at Hardware Ranch, we were looking at precipitation intensity with climate change, you get fewer larger precipitation events because warmer air can hold more water and then that means that more water that actually gets deeper into the soil. That tends to help shrub and tree growth.” Kulmatiski said. “So it's a potential explanation for the shrub encroachment we've seen in the past 50 years around the world. For a long time, people thought that it was because of fire suppression or overgrazing and CO2 fertilization. But it seems like larger precip events are also driving that increase.”