David Montgomery and Anne Bikle bought a modest house in Seattle. They discovered that the glaciers that passed through that part of the world long ago left them with very little topsoil in their backyard. They began dumping a lot of organic matter in their space and creating a manure tea to feed their plants. After a few years, they had soil and lush foliage to show for their efforts.
David is a geologist, used to thinking in geological time. It surprised him that by actively adding organic matter to the soil, he and Anne could actually speed up the rate of soil creation relative to nature’s timeframe. They both began to wonder how this could be and this led them to discovering the hidden world of soil microbes and their relationship to plants.
Of particular interest to gardeners is the first part of the book that so clearly explains in an accessible manner the interactions between the microbes in the soil (primarily bacteria, protists, and fungi) and plants. Research over the last 10 to 20 years has illuminated the incredible partnerships between beasties we can’t even see and plant roots, resulting in a sharing of resources and information in ways not previously dreamed of.
David and Anne make a very strong case for encouraging these relationships by not tilling the soil and adding a lot of mulch. And they illustrate what is lost when the opposite happens – soil is disturbed by tilling and plants are fed chemicals, resulting in basically sterile soil.
When Anne suffered a battle with cancer, the two began to look more closely at what supports human health and drew parallels between a healthy human gut and healthy soil, in that there is much more communication between the microbes in our guts and our immune system than we had imagined and keeping this inner microbiome healthy is very important to our overall health, as is supporting healthy soils.
Along the way they describe how microbes were discovered and how for a long time were seen only as enemies, aka disease-producers. So our first knowledge and awareness of microbes was in a battle against pathogens. There follows a long section on what the good microbes in our gut do and how to encourage them. While the center section is long and detailed, it is important in that it makes a case that the vast majority of microbes are beneficial and we need to cultivate them.
Page 254: “A couple of decades ago, it would have sounded crazy to argue that plants and microbes in the soil run a biological barter system that functions as a plant‘s defense system and allows us to harvest nutrient-laden plant foods essential to our health. Even more unbelievable would have been the notion that bacteria communicate with our immune system, helping it to precisely mete out inflammation to repel pathogens and recruit helpful commensals. These surprising new truths carry fundamental implications for the way we view, and should treat, a wide range of seemingly unrelated maladies. In medicine, as in agriculture, what we feed our soils—inner and outer—offers a prescription for health forged on the anvil of geologic time….Put bluntly, many practices at the heart of modern agriculture and medicine—two arenas of applied science critical to human health and well-being—are simply on the wrong path. We need to learn how to work with rather than against the microbial communities that underpin the health of plants and people.”
One of the best parts of this book is the readability and ease of understanding of complex topics. If you are on a quest to better understand our soils and the importance of cultivating their health, this is a good place to start.
Book Review by Ann Guthals