Soil and water

Indiana University researchers study the link between agricultural management, soil microbes and drought resilience

Indiana University researchers are studying how microbes can make plants resistant to drought to help farmers make the right management decisions.

“Microbes play an important role in the life of plants and animals, both positively and negatively,” explained Lana Bolin, Ph.D. candidate for the biology department at IU. “On the one hand, microbes can be pathogenic and harm other organisms. On the other hand, microbes can be extremely beneficial to other organisms. Plants generally benefit from bacteria and fungi that help them acquire nutrients and ward off pathogens.

The researchers collected soil from 70 farms in Indiana, Illinois and Michigan and brought them to a greenhouse at IU. They then inoculated corn plants grown under water-stressed or well-watered conditions with soil.

“At the end of the experiment, we will weigh and count the corn kernels produced to see how our microbial and watering treatments affected corn yield,” Bolin told Indiana Environmental Reporter.

The project, a collaboration between ecologists and sociologists, also involved in-depth interviews with farmers to understand how they manage their fields, including decisions about irrigation, cover crops and tillage methods.

The researchers said they could draw a link between agricultural management practices and drought tolerance. In some cases, microbes have grown with these practices

“Drought doesn’t reduce plant growth as much if plants are grown with microbes from dry environments, compared to when they’re grown with microbes from humid environments. And we don’t have a clue. very clear why that is,” Bolin said. “One possibility is that the traits that microbes express that help them survive drought also benefit plants.”

Researchers found that drought reduced plant height by 15 to 47 percent, depending on which farm the microbes came from.

Some bacteria create a sticky substance called biofilm that helps them survive drought stress, and these biofilms can coat plant roots and prevent water loss from roots during drought.

“Another possibility is that plants can tell which microbes are most beneficial, and they might increase the fitness of those beneficial microbes in some way. But that’s an open question, and we hope the approach with our research.

Researchers are still collecting data on this experiment, but substantial variations between farms in the resilience they impart to plants in terms of growth have been observed.