Most of us, especially city dwellers, probably don’t give much thought to what’s beneath our feet. Unless you’re a gardener, the idea of soil may be more akin to dirt – the stuff you have to scrape off your shoes before you track it in the house, or wash off of your car periodically. But healthy soil is a key component in the cycle of life on earth. Without it, we wouldn’t be here.
What we choose to eat has a direct impact on soil health. Commodity monocrop agriculture, with its heavy tilling and chemical use, actually destroys the soil’s ecosystem. But food produced in a regenerative way, with cover crops, organic practices, and well-managed grazing, can repair damaged soils and recreate the thriving cycle of soil, water, plants, and animals on which life depends.
Dr. Patrick O’Neill of Soil Health Services, PBC in Alamosa, Colorado, says the most important aspect of soil is its ability to hold water, which allows plants to transfer energy from the sun into feed for ruminant animals, which then enrich the soil, and allows the whole cycle to start over again. “Soil is the medium for intercepting water, for having water for plants to grow, and then for allowing water to infiltrate into aquifers and eventually to come back out as transpiration through plants. So, at its most fundamental, that’s one of the biggest reasons why soil is important.”
In order for soil to perform its role in the water cycle, a teeming network of bacteria and fungi—known as the soil microbiome—works in concert with nematodes, insects, and plant roots to create spaces in the soil so it can act like a sponge to soak up rain and snowfall. The microbes also feed on the exudate from plant roots, turning it into nutrients that then nourish the plant in return.
There’s another important aspect to soil health, and that’s its ability to store carbon. The process of carbon sequestration removes carbon dioxide, a greenhouse gas, from the atmosphere and locks it into the soil. Excess tillage and leaving fields unplanted for part of the year allows the carbon to escape back into the air where it contributes to climate change, but healthy pastures with healthy soil can mitigate that damage.
What part do grazing animals play? Ruminants (cattle, sheep, goats, bison, deer, and elk) eat plant matter that contains lignin, a complex carbon-containing molecule that gives plants their rigid shape. Unlike the microbes in the soil (and people), grazing animals can digest the lignin, and then deposit what’s left on the soil surface in the form of manure. The carbon and nutrients then are further digested by insects, fungi, and bacteria, locking the carbon into the soil and keeping the cycle running. Without grazing, the plant matter would eventually form a solid mat on the surface of the soil, which slows its decay, releases carbon into the atmosphere, and keeps water from penetrating the soil, thus interrupting the cycle.
Grazing allows the carbon from the biomass “to cycle more rapidly into the microbial space in the soil and then form deeper depositions of carbon and longer stored carbon over time,” says O’Neill. “And beyond that, if the plants are managed thoughtfully and the movements of grazing animals are managed thoughtfully, you can get a positive feedback loop. If your grazing animal takes a portion of the plant’s above ground biomass and leaves behind ample leaves for regrowth and restoration of that same plant canopy and root system, you can get what’s effectively a system pumping carbon into the soil instead of a net outflow of carbon from the soil.”
Is it a complex system? Yes. But you don’t have to be a soil scientist or even a rancher or farmer to do your part to keep the system thriving. All you have to do is buy organic, grassfed meat produced on well-managed grasslands by ranchers who are stewards of the land—and the soil cycle.