The Dirt on Dirt

Did you know that soil is alive or, to be more precise, that it should be full of life? This concept fascinated me when I was first informed of it. I had seen worms and beetles in my garden but had never considered the health of soil being equated to the living things that were in it. In fact, one teaspoon of soil has more living organisms than there are people on Earth. How is this possible? Aren’t there seven billion of us now? Well, it turns out that it’s true and this critical piece of information impacts us all. The health of the soil = the health of the people. Let’s explore this idea.

WHAT EXACTLY IS SOIL?
According to The Rodale Book of Composting, soil is a combination of sand, clay, and silt. How these components group together is referred to as aggregates. The element of soil that supports life is the humus. Humus is some combination of organic matter such as grass clippings, twigs, and leaves you’ve raked up, manure, and it can even include the decay of dead animals. Ashes to ashes, right? It is the humus that gives the life in the soil its opportunity to thrive.

WHAT LIVES IN THE SOIL?
Earth’s soils are inhabited by a variety of life forms, many still to be discovered. But we have a pretty good idea of who has taken up house. The smallest living creatures in our gardens include bacteria, actinomycetes, protozoa, and fungi. These guys are all microscopic in size but are the most abundant residents of the soil. Life forms you can see with your naked eye include mites, millipedes, centipedes, snails, slugs, spiders, beetles, ants, and earthworms.

According to “Sustainable Good Foods Consultant” David Cohlmeyer, “A prime indicator of healthy soil is that the biology can quickly spring into action to break down large amounts of organic material in a few weeks. The best single measurement of healthy soil is the percentage of organic matter.”

A NETWORK OF DECOMPOSERS
So what happens when your grass clippings meet some of the billions of bacteria in your garden? The activity of a living soil is fascinating and complex and most of it cannot be seen by the naked eye.

The physical decomposers are the worms and bugs. They chomp at the bigger pieces of organic matter and break it down for the smaller guys.

The chemical decomposers are the bacteria, actinomycetes, protozoa, and fungi. These microscopic soil dwellers start the process of breaking down any organic matter. They are experts in releasing minerals and nutrients into the soil. They don’t have teeth so they use acids and enzymes to break down what remains of the twigs and leaves. Fungi, my personal favourite, have many roles in soil health: they can break down organic matter, send messages through the soil to plants and other fungi, and help hold soil together to reduce erosion.

David Montgomery, co-author with Anne Biklé of The Hidden Half of Nature, notes that, “Forest networks of fungal hyphae (a long, branching filamentous structure of a fungus) are the largest forms on Earth, forming subterranean networks that extend for miles. A single teaspoon of fertile soil can contain a half mile of fungal hyphae. ”There is a network of life thriving, communicating, cooperating, and creating below ground.

HEALTHY PLANTS
So why are soil organisms doing all this work? Now that we have set the stage we can talk about the food we grow in soil. Fresh, whole food should be full of nutrients; the nutrients must come from the soil. After the big bugs break down the larger matter, the bacteria and fungi go to work releasing nutrients into the earth. Plant roots grow deep in the sand, silt, clay, and humus looking for nutrition. In healthy soil, plant roots spark a relationship with the bacteria and fungi. The plant will release carbohydrates into what is referred to as the rhizosphere, the area around the roots of a plant. The carbohydrates feed the soil organisms and they, in return, provide nutrients for the plant to grow. While incredibly complex when we consider all the chemical reactions happening in healthy soil, we can simplify by saying there is symbiotic relationship between plants and soil.

SO WHAT’S THE PROBLEM?
Unfortunately we have adopted many agricultural processes that disrupt the balance of soil health: pesticides, fungicides, chemical fertilizers, and soil tillage to name just a few. We are quite simply wiping out the life in the soil. After the Second World War it was thought we could replace the work of soil organisms with fertilizers and agrichemicals. It turns out that this is not true.

THE HUMAN MICROBIOME
Much like antibiotics wipe out the good bacteria in our guts, chemical pesticides reduce the amount of beneficial life in the soil. It is now widely accepted that the overuse of antibiotics has had a detrimental impact on our well-being. The National Institutes of Health’s Human Microbiome Project was founded in 2008 to determine the role of human microorganisms and human health. It’s still early on in the studies, but bacteria and other microorganisms in our digestive system do play a key role in our overall health. The parallel between a plant’s rhizosphere and the human colon is striking.

In their book, Montgomery and Biklé state: “People are dialed into the same biologically based defense strategy as plants.” They go so far as to say that, “The root is the gut and the gut is the root.” If healthier soils produce healthier foods, this directly affects gut health. As the interest in the human microbiome grows, it seems logical to investigate the soil’s microorganisms simultaneously. We’re onto something.

NUTRIENT DEFICIENCY
Lifeless soil cannot produce healthful food. Synthetic fertilizers cannot replace the work of soil organisms. As a consequence of modern agriculture, nutrient levels of whole foods have eroded in the last fifty years.

In a 2004 study at the University of Texas at Austin, Dr. Donald R. Davis compared the nutrient content of fruits and vegetable from 1950 and 1999. His team observed a “consistent decline” in key nutrients including protein, calcium, phosphorus, iron, and vitamin C. In addition to soil deficiency, it appears that when developing plant variety traits, size and yield have superseded nutrition and flavour profiles.

When we consider modern agriculture practices, plant variety development, and the increased reliance on processed foods in our modern diet, a nutrient deficit becomes inevitable.

Luckily, some key people have been turned on by the human and soil health connection. David Cohlmeyer is currently working with Dalhousie and Guelph universities on a project to demonstrate that there is a correlation between biologically active soil and (phyto)nutrients. Cohlmeyer says, “It is safe to say that healthy soil produces more flavourful food. I like to assume that appealing (natural) flavours are our bodies’ way to guide us to select the most nutritious food.”

CLIMATE CHANGE
There’s more to the equation “health soil = healthy people.” We can expand on the benefits of healthy soil to the health of the planet. It turns out the Earth’s soils sequester huge amounts of carbon. Unfortunately deforestation, erosion, and the loss of soil microorganisms reduce the soil’s ability to hold onto carbon, thus contributing to climate change. Rebuilding organic matter in our farmers’ fields could be part of our climate change solutions. Healthy soil is a natural resource we must value and protect.

SOLUTIONS
The average Canadian might feel at a loss as to how to contribute to rebuilding soil health. It can seem so far removed from our daily reality; very few of us, after all, are farmers. Every single one of us, however, is an eater. You have already made a difference by reading about and understanding the importance of soil health and human health. You can now make educated choices when you eat:

• Choose organic. The Organic Center out of Washington, D.C. has done several studies on the elevated nutrient content of organic foods. This is, in most part, due to the natural treatment of soils in the organic agricultural system. There are consequences to cheap, conventional food. David Cohlmeyer so eloquently remarks, “The question is not why is organic so expensive but why is conventional food so cheap?”
• Shop at your local farmers’ market and ask the vendors about their soil health management practices.  
• Compost your food and grow an edible garden. Even your small vegetable plot can make a difference. When asked for her thoughts on this, Anne Biklé responded, “On a small scale, say that of a neighbourhood, school, or park, something tangible like a vermicomposting project or a food or community garden, can give people—especially young kids—a way to get involved with soil stewardship. People tend to take better care of, and develop an appreciation for, the things they understand.”
• Get political. Ask your local political leaders if they consider soil to be an important natural resource. Ask them if there is a longterm plan in place to preserve and protect our soils.
• Join and support local environmental stewardship movements, such as Food and Water First. This highly effective group of citizens works to protect Class 1 farmland in Ontario.

Food and Water First
www.foodandwaterfirst.com