David R. Montgomery on the Soil Science Revolution

David R. Montgomery, author and Professor of Geomorphology at the University of Washington, explains how advances in technology are helping soil scientists explore the connections between soil life and plants.

Transcript: The real revolution in understanding the role of microbial soil life and soil fertility can be ascribed in great part to gene sequencing. New technologies that allowed essentially a new pair of glasses for scientists to look at the microbial world and see the interactions among communities of organisms and actually test ideas for who’s doing what and how that all works. It used to be that soil ecologists thought that everything was everywhere, that there was a low abundance of same microbes all over the world. But as people started to look into it, what they’re seeing are that—there’s very uniquely adapted communities of microorganisms in the different zones around roots of different plants. There’s different communities. And the functional groups are fairly similar. There’s microbes that break down organic matter, that facilitate nutrient transfer, that communicate with plants, but the species are different. So the whole understanding of that world and their connections has been revolutionized in the last 20-30 years. Even through the ability to use radioisotope tagged molecules to trace them through living systems are techniques that have opened the window on the mechanisms of how these connections work that were a mystery to the people who first proposed the relationships, say between soil fertility and mycorrhizal fungi back in the 1930s. People like Sir Albert Howard who had connections between the soil health, the health of soil life, and the health of crops—the fertility of the land—but he didn’t have the mechanisms for how they work. So new technologies have been giving us insight into how those processes actually work, and if there’s one thing scientists are really good at, it’s pooh-poohing things that we don’t understand the mechanisms for. You can look at the adoption of plate tectonics in my field of geology. Until it was understood how continents could move around the surface of the earth, it was considered a crazy idea. Now it’s in all the textbooks. The ideas of symbioses in soil life and the connections between microbial life and plant health have gone through a similar kind of revolution where we can now see how they work in ways that allow us to ask more sophisticated questions and get beyond the question of “is there a connection?”