Editor’s note: This commentary is by Ron Krupp, who is the author of “The Woodchuck’s Guide to Gardening” and “The Woodchuck Returns to Gardening.” and is working on his third Vermont garden book called, “The Woodchuck’s Guide to Landscape Plants and Ornamentals.”
Dr. Rich Bartlett, the head of the UVM Plant and Soil Science Department, taught me about what makes soil healthy, when I worked as a graduate student for him in the 1980s. He taught me about the symbiotic relationship between mycorrhizal fungi and the roots of plants.
In Latin, mycorrhizal means fungus-root. A white fungal network called hyphae, not plant roots, is the principal structure not only for the uptake of important nutrients in the plant kingdom, but also for carbon sequestration in the soil – so critical in our world of climate disruption.
Polish scientist Franciszek Kamienski gets credit for discovering in the 1880s that the fungus and plant combination was a mutually beneficial partnership.
What is called a mushroom is merely the temporary structure some fungi grow to produce spores. The main body of a fungus typically consists of a network of fine-branching threads known as “hyphae” mentioned above. While you’ll sometimes see them massed together, spread like a web across a decomposing log, they’re usually hidden underground and essentially invisible to us; the individual filaments are only a single cell wide.
The network of fungal hyphae is called a “mycelium.” As it turns out, the largest known creature on Earth is neither a blue whale nor a redwood tree; it’s the several-hundred-ton mycelium of one humongous fungus that’s between 2,000 and 8,000 years old in Oregon’s Blue Mountains. By contrast, the mycelia of most species are small, but they’re as common as, well, dirt. If you pick up a pinch of soil almost anywhere, you’ll have miles of hyphae in your hand.
The outer walls of hyphae contain gluey compounds that cause fine particles of earth to clump together on and around the threads. This process is a major factor in building soil structure and making the ground less vulnerable to erosion.
During photosynthesis, plants use solar energy to extract carbon molecules from carbon dioxide in the air to make carbohydrates or sugars. Ten to twenty percent of the carbon-based sugars are later exuded from the plant’s roots, feeding bacteria and fungi in the nearby soil. In turn, these microorganisms symbiotically transform soil minerals into nutrients that feed plants and help them fight disease, increase drought resistance and trap carbon in the soil for decades, even centuries.
Mycelial networks play a valuable role in sequestering carbon. Twenty years ago in an experiment by the Rodale Institute of Kutztown, Pennsylvania, found that there was much more microbial activity in organic soils as compared to conventional chemical soils. They concluded that the solution to global warming was right beneath our feet. In 2015, the institute produced a white paper stating: “We can sequester more than 100% of current annual CO2 emissions with a switch to widely available and inexpensive Regenerative Organic Agriculture practices.”