Seeking Safer, Saner Agriculture Through Mycorrhizal Fungi

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To promote the beneficial fungi that boost plants’ access to nutrients, farmers and gardeners should till the soil as little as possible and use natural methods to suppress weeds. Here, stalks decompose in a no-till field in Ohio.

We are especially proud of our story, Mycorrhizal Fungi: The Amazing Underground Secret to a Better Garden, which explains one key way we can improve our gardens: by supporting the astonishing partnership soil fungi form with plants.

New scientific understanding of this relationship has emerged over the past few decades, and we now know that invisible networks of super-thin fungal threads (hyphae) are the principal structures for nutrient uptake for plants — not plant roots alone, as we had previously thought.

Scientists have discovered that this partnership is more than 400 million years old. So far, they have identified more than 6,000 species of these fungi — called “mycorrhizae” — that support crop and tree growth.

These extensive fungal networks interconnect with roots, making plants more drought-tolerant and extending plants’ access to many nutrients by up to 2,500 times! Plus, the fungal threads help hold topsoil particles together, protecting the soil from erosion.

The fungi-plant relationship is symbiotic, meaning that both organisms benefit from it. The fungi deliver nutrients to the plant and, in return, the plant releases 10 to 20 percent of the carbohydrates it produces to the fungi. If there are no plants to feed them, these beneficial fungi die.

To promote this fungi-plant partnership, we should change several things about how we farm and garden. First, we should till the soil as little as possible. Second, we should avoid using chemical pesticides. And, third, we should never leave soil bare, even in winter. Instead, we should cultivate cover crops to keep live plants growing in our beds and fields year-round.

Many organic gardeners and farmers already know something about this myco-rrhizal (meaning fungi-root) arrangement, so they try to reduce tilling, reject pesticides and plant cover crops to protect the mycorrhizae. But conventional industrial farming depends heavily on routine applications of pesticides that are toxic to the entire ecosystem. We hope farmers pay attention to this new knowledge and explore its potential to lead us to a more sustainable system.

Changing old habits is always hard. Can farmers find ways to modify their machinery so it disturbs the soil less? Many have already made the big switch to low-till methods, but in large-scale operations that practice currently depends on herbicides for weed control. Will they investigate ways to eliminate herbicides and suppress weeds with cover crops that in turn support the mycorrhizae and generate essential nitrogen? Some farmers already pull seed drills or spinners behind combines to sow winter cover crops as they harvest, and some collect a bonus by grazing their livestock on established winter cover crops.

But the chemical companies can profit more by defending the status quo. Vested interests, determined to sell more and more herbicide-tolerant, genetically modified crop varieties, will certainly not blaze the trail to explore the potential of plants’ ancient partnership with mycorrhizal fungi. It is up to our wisest farmers to push for more research and lead the way to safer, saner, more sustainable ways to grow our food.

(If you want to become a wiser farmer, we recommend these resources: Acres USA, The Stockman Grass Farmer, and the Sustainable Agriculture Research & Education program.)