Finding the right fungus

First steps taken to identify and promote fungi beneficial in cropping systems

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Do you have fungus? Your fields certainly do, though the varieties vary based on several factors.

While tillage levels, rotational diversity and cover crops affect fungi type, they don’t appear to have a significant impact on population.

These conclusions come from a University of Guelph study that analyzed fungal communities in long-term horticultural and corn crop trials.

Why it matters: Micro-organisms play an important role in field ecosystems. Determining which fungi help or hinder specific crops and how fungal populations could be controlled, could boost quality and yield.

Kari Dunfield, professor in the university’s School of Environmental Sciences and one of the project’s lead researchers, says the long-term trials showed how production causes microbial communities to shift.

This identification, says Dunfield, is the first step in determining whether specific fungi are affecting crop yield and quality, for good or ill.

After analyzing fungal populations in horticulture rotations with cover crops and a no cover crop control, Dunfield and her colleagues found little difference.

Cover crops appeared to not significantly change fungal populations and what changes did occur appeared random. This unexpected result appears counterintuitive given conventional understandings of the relationship between crop diversity and soil microbiology.

“There wasn’t an obvious shift. There are trends and shifts depending on what cover crops are there, but you don’t see a completely different situation. You don’t see any communities,” she says. “We’re looking at microbes that are present. I think covers will shift communities, but in the no-cover system they’re still there because they have a lot of things they can survive on.

“You have to consider the system. Bare soil would probably be a different story.”

Another component of the study looked for fungal population differences in corn-based systems, from straight corn to rotations containing corn, soybeans, wheat, clover and alfalfa. Conventionally tilled and no-till controls were also included in each system.

Like the impact of cover crops, or lack thereof, the researchers were intrigued to find conventional tillage did not appear to reduce fungal populations. Conversely, more crop species did not equate to higher populations.

What did occur in each case were population shifts. More species in the rotation changed the types of fungus present in the soil. Similarly, the type of fungus present in tillage systems were completely different than those in no-till systems.

Dunfield says this poses the question — what types of fungus do different agronomic practices promote and are they helpful or harmful?

“What can we do to promote the ones we want there and minimize the ones we don’t want there?” she says. “We know in corn-soy-wheat rotations we have more resilience in yields. Maybe the idea is we change the microbe populations to withstand (stresses) in the growing season.

“Are there key organisms we should be looking for? That’s one of the things we’re doing next.”

About the author

Contributor

Matt McIntosh

Matt is a freelance writer based between Essex County and Chatham-Kent. He is interested in all things scientific, as well as rock n' roll, hunting and history. He also works with his parents on their sixth-generation family farm.

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