Management practices can enhance soil microbiome functions in plant defense

The soil microbiome is critical for the ecosystem, and agricultural practices that promote microbial diversity can support plant health and help protect against pests. But it is unclear which practices are most beneficial, and what motivates farmers to choose them.

In a new study, researchers from the University of Illinois Urbana-Champaign and Cornell University analyzed surveys and soil samples from 85 organic farmers in New York to investigate the interaction between beliefs, management practices and soil microbiome functions.

“Our goal was to build a socio-ecological model that looks at how farmer beliefs about the soil microbiome mediate their management practices, and how those practices in turn affect ecological responses,” said lead author Elias Bloom, postdoctoral research associate at Cornell University.

Co-authors on the study are Clare Casteel, associate professor in the School of Integrative Plant Science at Cornell University, and Shadi Atallah, associate professor in the department of agricultural and consumer economics, which is part of the College of Agricultural, Consumer and Environmental Sciences at the University of Illinois.

In a previous study, the researchers discussed how farmer beliefs about the microbiome affected their management practices. In the current study, they combined information about practices with laboratory analysis of soil samples the farmers provided. They conducted DNA sequencing to determine which species of microbes were present in the soil samples and correlated that with the management practices the farmers reported using.

They also mixed microbiome extracts from the soil samples with potting soil and grew pea plants, then introduced aphids to the plants to evaluate their pest-suppressing abilities.

Casteel said, “Conducting these experiments in the field is challenging because so many factors influence plant health. By bringing field soil into the lab, we're able to control these influences and focus on the soil microbiome, helping us build stronger evidence."