“Despite all our accomplishments, we owe our existence to a six-inch layer of topsoil and the fact that it rains.”
– Paul Harvey
My father’s quest to build topsoil from dump treasures
My dad was a soil man. No he wasn’t a pedologist (a scientist who studies soil), but more of a naturalist or recreational agrologist who consumed stacks of Harrowsmith magazine. We lived on the Canadian Shield, where my father’s self-assigned mission was to make soil on our little slice of granite-bedrock dominated heaven. I was that weird kid who spent a lot of time at the local dump. And, while most families were there to throw stuff away, my time there was a Herzog-esque saga, loading rotten logs, old newspapers, and anything that looked like it might decompose into a giant green trailer. We were the only folks in our rural neighbourhood who drove to the dump empty and returned home full.
The strange mission of making soil on granite bedrock
When we got home, the placement would start. Wheelbarrows of discarded fill, leaves, and compost would make their way into our outback, covering the pink granite, to my mother’s chagrin. Branches, stumps full of dry rot, even discarded pets and hunting refuse (I wish I was joking). And so it went, over the years, stretching into decades as my father proudly proclaimed to anyone who would listen: “I bet we have at least three inches more topsoil than anyone else!” It was a quixotic quest that, to this day, I find baffling.
He was right, though. Soil is incredibly important. My father was trying to game a natural system that takes eons. It’s estimated that it can take anywhere from 100 to 1000 years to create an inch of topsoil, although this varies with location and climate.
Understanding soil horizons: A crash course in what’s beneath our feet
Soil itself is an incredibly engaging and complex topic. While most of us are concerned with how it makes our gardens grow, one would be remiss to skip over a basic understanding of what lies below our feet. So here’s a crash-course in pedology to make trenching that next drainage ditch around your perimeter a little more interesting.
Soils are characterized by horizons [listed here from the top down – Ed.]
O) Organics. Your grass, leaves, sticks, etc. (Tree planters know this as “duff.”)
A) Topsoil, the good stuff that makes your plants grow. A combo of decomposed organics from above and minerals from below.
E) The eluviated layer. Primarily sands, silts, and other resistant materials.
B) Subsoil, aka minerals that have leached downwards.
C) This is the parent material or the deposit from which the soil developed. If you’re digging a drainage ditch, you’ll be swearing a lot at this stage.
R) Bedrock. Sandstones, shales, granite, basalts, limestones, quartzite, etc. Typically quite deep in the Comox Valley.
The incredible ecosystem living in every cubic centimeter
Of course this presents a really simplified overview. Even more interesting is what lives in the soil itself—primarily in that top layer. It’s a rich habitat that sustains much of our terrestrial life. For example, in a single cubic centimetre of soil, it’s estimated that there can be over 11 km of fungal mycorrhizal strands, in addition to hundreds of thousands of mites and rotifers. That same cubic centimetre is home to 100 million to a billion bacteria.
North America’s topsoil crisis: Half our soil lost in 150 years
It’s hard to over-exaggerate the value of soil. Yet, here in North America, it’s estimated that we have lost over half of our topsoil in the last 150 years. Whenever we disturb the soil through agriculture, timber harvesting, or other industrial activities, it becomes susceptible to erosion from wind, heavy rains, runoff, and fire activity. It has only been through our increasing reliance on artificial fertilizers and other technology that we haven’t sustained a major decrease in agricultural yields.
Everything from our food supply to our forest resiliency is predicated upon having healthy soils. After my father finally sold the property, the new owners scraped the soil down to the original bedrock for aesthetic reasons. It was then that I finally glimpsed the importance of his vision—and the value of my childhood days spent at the local dump.
Check out our article from Comox Valley Collective Vol. 8 on composting tips.
