By S.K. Rosina Newton
As the sun moves higher in the sky, warming our bones and our soil, we might find ourselves more frequently drawn outside. We venture into our personal landscapes just outside the door, onto the trails of our neighborhood park, or even Nichols Arboretum, looking for more signs of life emerging from the earth.
What is our personal connection with this green world outside? Some of us have started a spring vegetable garden, some of us hike or play regularly in the wild, and some of us might not know anything about plants—we just know what looks beautiful to us or how good we feel after spending time outdoors.
Having a yard—our little corner of Earth—is a great opportunity. What we do here reflects our creativity, as well as our understanding of nature. Our home’s landscape is a microcosm of the huge subject we call the environment. Our choices here can have surprising effects on our own health and on our greater environment as well.
Soon after graduating from Texas A&M University, with a horticulture degree under my belt, I mentioned to a fellow agriculture graduate that I wanted to use organic fertilizers. My friend said, “That plant can’t tell the difference between a nitrogen molecule that comes from an organic fertilizer and a nitrogen molecule that comes from a synthetic!” At the time I didn’t know enough to have a comeback; my alma mater didn’t teach organic horticulture back then. Now, after 30 years “in the field” in Texas, New York, and now Michigan, I’ve learned there is so much more than meets the eye when we are talking about plants.
John Muir wrote in My First Summer in the Sierra, “When we try to pick out anything by itself, we find it hitched to everything else in the Universe.” We know that “life is all connected,” but what does that truly mean? To try and answer that, let’s start at the beginning: all of life on earth depends on plants. Plants are called producers because they can take the sun’s light energy and—through the miracle of photosynthesis—turn it into food for themselves. Every living thing on earth depends on this primary food energy from plants.
Remember the food web that we learned about in school? The plant is breakfast for a caterpillar; a bird eats the caterpillar; and a fox eats the bird. There is also a soil food web happening under our feet, too. In Teaming with Microbes, authors Jeff Lowenfels and Wayne Lewis say, “A mere teaspoon of good garden soil … contains a billion invisible bacteria, several yards of equally invisible fungal hyphae, several thousand protozoa, and a few dozen nematodes.”
In the wild—whether in the Amazon rain forest or a temperate forest in Michigan—a healthy ecosystem has its own sustainable system of fertility, pest, and disease control and maintenance. Leaves fall, animals and microbes defecate, and plants and animals die. The microorganisms living throughout the soil consume these ingredients in the process of decomposition, turning them into available fertility for the plants. The final product of decomposition is what we call organic matter. This, mixed with the broken-down native bedrock, is the recipe for soil.
In other words, there is no need for a human being to go into the wild jungles with a bag of fertilizer and bug spray to maintain the plants. In native ecosystems around the world, there are connections between plants and microbial life that perform all the functions necessary to keep the vegetation going and to keep pests in check. Only in recent decades has science really begun to discover the true extent of these complex plant-microbe relationships.
Some of these discoveries about plant-microbe relationships seem to be straight out of a science fiction story. In his 2015 book The Hidden Life of Trees, Peter Wohlleben echoes what Lowenfels says, “There are more life forms in a handful of forest soil than there are people on the planet.” He goes on to say that if caterpillars begin eating the leaves of one tree in a healthy forest, the tree can respond several ways. It will pump distasteful and harmful tannins out to the leaves. It also releases a compound into the air that attracts predators to eat the caterpillars. Not only that, he reports that trees “also warn each other using chemical signals sent through the fungal networks around their root tips. ... Surprisingly, news bulletins are sent via the roots not only by means of chemical compounds but also by means of electrical impulses that travel at the speed of a third of an inch per second. … Once the latest news has been broadcast, all oaks in the area promptly pump tannins through their veins.”
Arbuscular Mycorrhizal Fungi—this is the name for the type of fungus that has this specific beneficial connection with plants. Eighty percent of all plants on earth are connected to AM fungi! In addition to helping trees communicate, they assist with everyday maintenance of plants. By penetrating inside the plant roots, these fungi are able to deliver more nutrients, minerals, and moisture than the plant can get for itself. In the most prevalent symbiotic relationship on earth, these fungi supply the materials plants need, and in return the plant gives the fungi sugars it produced through photosynthesis.
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Right here in Ann Arbor, there are studies being done that are shedding more light on these incredible connections. On a chilly evening in February, I sat down at Black Diesel Coffee with Professor Mark Hunter to talk about the invisible world of plant-microbe connections. He is the Earl E. Werner Distinguished University Professor of Ecology and Evolutionary Biology at the University of Michigan. In the late 1980s he worked with the original “talking tree guy” Professor Jack Schultz at Penn State who did some of the earliest studies on plant-to-plant communication. Professor Hunter has been at U-M for 14 years. He and his graduate students are revealing some magnificent discoveries.
Professor Hunter says this “trading partnership” between plants and AM fungi is 460 million years old. “Everything a plant does, whether it’s communicating with other plants, communicating with insects, pollinators … is influenced by mycorrhizal fungi.”
In a series of studies, he and two of his students, Nate Haan and Rachel Vannette, discovered that wildflower plantings across Ann Arbor failed wherever there was a lack of AM fungi. It is remarkable enough to notice that plants are able to better succeed when they are placed in a soil rich with their fungal allies. But the influence of these fungi goes even further. Professor Hunter and his student, Leiling Tao, discovered that when Monarch butterflies sipped on the nectar of milkweed plants that were grown in soil lacking AM fungi, they were more susceptible to a parasitic disease. If Monarchs were given milkweed grown in fungal-rich soil to dine on, they were more resistant.
These discoveries are truly astonishing! Thinking about the implications of this in relation to our own health: are our vegetables and fruits grown in soil that is rich with AM fungi?
I talked with David Saturn Klingenberger, the founder and Chief Fermenting Officer of The Brinery in Ann Arbor. He expressed it very clearly. “There is a direct correlation between the microbes in the soil and the microbes in our gut. We are not separate from the soil—we have coevolved with it. A healthy soil is directly related to a healthy human body.”
Let’s explore this even further. There is a community of microbes living inside and outside our bodies that is analogous to the plant-soil-microbe system. In fact, we are more bacteria than we are human! Yes, the cells of bacteria, archaea, protozoans, and fungi living on and in our healthy human body outnumber our human cells. We have been learning only in the last decade or so how completely dependent we are on our human microbe allies.
This is perhaps why our ancestors included fermented foods and beverages in their diet, and why authentic sauerkraut, kimchi, and kombucha have become so popular. Fermented foods are nature’s probiotics and eating them helps to restore and maintain a healthy balance of beneficial microbes in our bodies.
I asked Rachel Kanaan about this. She is cofounder and co-brewer, with her husband Tarek, of Unity Vibration Kombucha in Ypsilanti. She says these microbes in our gut are “involved in many other important processes besides just the act of digestion—including your metabolism, body weight, and immune regulation, as well as your brain functions and mood.”
We are learning that being “too clean”—using antibacterial personal soaps and household cleaners, for example—is not good for us. It is comparable to taking antibiotics too frequently or unnecessarily. We simply need to preserve and increase the beneficial microbes of our bodies in order to stay healthy.
So, besides eating more fermented foods, how do we take all this information home, so that we can benefit from the microbial life that coevolved with us? I spoke to a number of local organic farmers, who were all very aware of the rich benefits of a living soil and were eager to share their methods with us. They have much in common, but one major choice is to avoid the synthetic fertilizers, pesticides, and especially fungicides that would destroy the microbial life on plants and in soil.
Richard Andres of Tantré Farm in Chelsea said, “We make a concerted effort to keep as much root in the ground as possible, because it’s where the fungi live.” At home, when our vegetable gardening season is over, that means we can simply cut off the top of the dead plants rather than pulling them up or tilling.”
Ben Kasmenn, the Farm Manager at Gateway Farm in Plymouth reinforced this principle. “First and foremost, we limit the amount of tillage we do in order to preserve the soil structure and integrity. We also rely on cover crops and compost to help feed the microbes and provide proper airflow, waterflow, and nutrient cycling. There are many other more specific techniques, all geared to preserving and growing a diverse, thriving, soil community. The microbes in the soil are the cornerstone to all life on this planet. Plants want to grow, and with a functioning microbiome in the soil they will grow without our help.”
Hannah Rose Weber, Farmer/Partner at Green Things Farm in Ann Arbor added, “Enabling and encouraging the microbial life in our soil by moving toward more no-till practices that do not disturb soil life is one very impactful thing we can do to help microbes help us. A more diverse soil biome means that no one pest or disease can easily take over and infect our crops, allowing us to spend more time growing and harvesting food and less time reacting to problems. Feeding the soil by planting cover crops and amending with compost is our way of preventing issues before they happen.”
Richard Andres at Tantré also shared that they keep 75% of the farm in pasture, along with native woods and wetlands. Professor Hunter said that “By far the best way to get native fungi into your soil is to grow native plants” and to amend the soil by adding compost. Compost and other organic matter, such as a natural, undyed mulch, can be added on top of the soil without tilling. These materials not only add native fungi and other microbes, but they provide food and protection for the microbes, enlivening our soil.”
And how does this help our greater environment? First of all, whenever we plant natives we are restoring habitat for native pollinators, birds, and other beneficial creatures. Not only that, Dr. Elaine Ingham, world-renowned soil scientist and microbiologist shared the following recently with Sustainable Living Guide.
As those fungi grow, they lay down massive amounts of carbon on the insides of the fungal tubes that they leave behind. And so when we get that fungal biomass growing in your soil, the way your healthy plants require, we can sequester up to—so far, we’re seeing—11 tons of carbon sequestered per acre per year. And that’s just when we’re measuring the biology in the top three or four feet of the soil.
Well, remember that that’s not as far down as roots go. Roots will go down 15, 20, 30, 100, 150 feet. And so, we can be sequestering carbon all the way down. We could take all that elevated CO2 in the atmosphere and within just a few years, we could put it all back into the soil from whence it came.
Now, as we move into spring and summer in Michigan, as life returns to our favorite places in nature, we realize we are seeing only part of this amazing story. Countless invisible colleagues living on plants and in the soil, along with beneficial insects and other allies, are protecting and promoting growth in plants wherever we go. When we are managing our vegetable gardens, lawns, or shrubs at home, we know our most productive choices will be to protect and contribute to this living system as best as we can, so our little corner of Earth can be solving some of the world’s most pressing environmental problems. As stewards, we are teaming up with the life around us, supporting our community, and enjoying its bounty.
Rosina Newton is an organic home and garden coach, environmental educator, and permaculture designer. She has planted trees, and taught children and adults in Texas, New York, and now Michigan. You can find support for your gardening interests at https://newearthhomeandgarden.com/
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