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What do mushrooms, Christopher Columbus, small pox, climate change, and your dinner all have in common? Read these five amazing soil facts to fin out!
Ever notice how much organic farmers, permaculture practitioners, and agroecology advocates talk about soil? Why is that? It’s just stupid ol’ dirt, dangit! A sterile, inert, lifeless medium that we have to plow, fertilize, and poison in order to grow our food in.
Who cares about soil? What’s there to know?
Lots actually. In fact, now more than ever, it’s critically important that you know what soil is, how it works, and why life as we know it would be (and will be) impossible without healthy, living soil covering the surface of our planet.
5 amazing soil facts
Fact 1: There are more living organisms in a handful of soil than there are people on earth.
Presently, there are about 7.5 billion human beings living on the soil surface of our planet. It’s hard to wrap our minds around such a big number…
To put those digits into historical perspective:
- At the dawn of agriculture, 8 – 10,000 BCE, there were about 4 million people on earth;
- During the U.S. Revolutionary War in the 1770s-1780s, there were about 800 million people on earth;
- In 1969, when the first man walked on the moon, there were about 3.7 billion people on earth.
A stock market bubble? Nope, that’s global human population growth since the dawn of agriculture. Image credit: El T – originally uploaded to en.wikipedia as Population curve.svg. The data is from the “lower” estimates at census.gov (archive.org mirror)., Public Domain, Link
Yep, there are a lot of us here.
Thus it’s important to consider the “magnification effect” that our collective behaviors have. If 4 million people do something, it might not be that bad. If 7.5 billion people do something, it might cause mass disruption to global ecosystems.
Since we all depend on soil for our survival (as we’ll discuss further below), the more people we have on earth, the more important it becomes for us to understand, appreciate, and create healthy living soils.
On that note, what’s actually in soil?
If you were to walk out into a mature forest or a farm where the soil was being well-managed (example: organic no-till farm), gather a handful of soil, and put it under a microscope, you’d likely be amazed.
Here’s what you’d see:
- 10-50 billion aerobic bacteria;
- up to 100 million different fungal cells (e.g. mushrooms) including strands of fungal hyphae that connect them into a functioning network;
- hundreds or thousands of arthropods and micro-arthropods;
- thousands of different algae, protozoa, and nematodes.
It’s also important to note that the majority of the microscopic species and subspecies in each of the above categories have yet to be classified, e.g. soil scientists don’t know exactly who they are or what they do.
Welcome to “inner space,” the vast and mysterious unknown beneath our feet!
The variety and quantity of microorganisms in a particular soil sample vary greatly depending on:
- where you are on the planet,
- what season it is,
- what plants are growing in the spot where the soil sample was taken, and
- whether or not the soil has been previously damaged by people or natural phenomenon such as fires and floods.
Soil in a particular location is akin to a fingerprint.
Regardless, after a thorough evaluation of your soil under a microscope, you’d find that there are probably 50-100x more living critters in your handful of soil than there are people on earth.
So what the heck are all those critters doing down there?
Fact 2: Soil Microorganisms Farm Plants and Plants Farm Soil Microorganisms
Understanding Plant Succession
Which comes first: the chicken or the egg? Which comes first: the fungi or the trees?
If you understand how plant succession works (see image above), you might know that the typical US garden or farm stays between a Stage 2-3 on a plant succession scale.
Annual plants (our primary food crops) are basically nature’s “scabs.” They’re fast-growing plants that rapidly cover exposed soil and put carbon-rich biomass back into the soil to allow for plant succession to continue onward towards the final forest stages of succession.
Nature uses plants to cover/protect its exposed living “skin” (e.g. the soil) with shade and decomposing biomass (leaves, twigs, etc.). That biomass is slowly eaten and incorporated into the soil by microbial decomposers, which then release those nutrients in a bioavailable form to plants. And the cycle repeats.
Why does soil cover itself?
Soil covers itself because exposed soil is irradiated by the sun, killing the microorganisms that hold it together and make it work. This die-off diminishes the soil’s water-, nitrogen-, and carbon-cycling capacities, not to mention its ability to fight diseases/pathogens and degrade pollutants.
That’s why exposed, tilled soil soon becomes dead soil, and dead soil washes away during storms or blows away when the wind blows. (See US Dust Bowl or the Middle East region for examples of these processes in action on both short and long-term time scales.)
What many people don’t realize is that “succession” isn’t just an above-ground phenomenon occurring in plants. In fact, what’s happening below the soil surface is equally or more important than what you can see with your eyes above the soil surface.
Annual, weedy plants tend to prefer bacterially-dominated soils with far less fungi than you’d find in a forest soil. That’s why/how annual plants are the first ones to grow on the soil surface of disrupted ecosystems… They’re the “scabs” of the plant world.
That’s why these early colonizing plants are referred to as ‘Pioneer Plants’.
That’s also why our farms that grow only annual plants have a fungal to bacterial biomass ratio of about 1:1 (the same as a grassland ecosystem). Conversely, a deciduous forest (hardwoods) will have a 5:1 – 10:1 ratio, and a coniferous forest (softwoods) will have a fungi-bacteria soil biomass ratio between 100:1 – 1000:1.
Interestingly, the more fungi in the soil, the more carbon the soil will store. (source)
Annual plants cultivate and promote specific strains of beneficial aerobic bacteria in their rhizosphere (the zone immediately around their root systems). In turn, those bacteria cultivate and promote annual plants.
As microbial succession continues underground, the relatively immobile bacteria (e.g. they can’t move fast or far) start glueing the soil together into aggregates so they don’t get washed out of the rhizosphere when water flushes through the soil system during rains.
Then in comes the highly mobile fungi that can produce thousands of linear miles of branching hyphae below the soil surface, bringing back nutrients and water to their plant hosts from distances far beyond the plant’s rhizosphere as well as protecting the plant roots from disease/infection.
When you see a mushroom on the soil surface, you’re simply seeing the “fruit” of a large underground organism. Of course, there are the functional equivalent of predatory and scavenger fungi as well, whose role is to eat or decompose sick, dying, or dead trees.
Neat fact: the largest organism on earth is a 2.5 mile wide saprobic Honey Mushroom (Armillarea ostoyae).
As the soil becomes more fungal-dominated, it ushers in the above-ground woody pioneer plant species and trees that grow in later stages of plant succession.
You might not have noticed at the time, but you’ve seen the amazing processes of plant and soil succession play out on vacant parking lots, abandoned yards, cleared fields, etc. thousands of times. Ecological succession is happening all around you right now!
Non-Autonomous Life Forms
If you’re starting to think you’re not that special compared to a tree or a handful of soil, despair not!
As it turns out, human beings contain more bacterial cells than human cells. We also have a huge range of other species living in and on us that make us work.
We refer to all of these organisms in the collective as our “microbiome.” That means you’re a superorganism!
Now, back to plants… Every tree species on earth forms symbiotic relationships with some combination of endomycorrhiza fungi (inside the root), ectomycorrhizae fungi (outside the root), and bacteria.
Why? Because those microorganisms feed the trees nutrients and water that would otherwise be unavailable to the tree roots alone. In exchange, the trees feed these microorganisms sugars and other goodies via their root exudates that they make via photosynthesis.
In fact, almost as much of a tree’s energy goes into feeding its symbiont microscopic workers as goes into feeding the tree itself.
Mycorrhizal fungi also serve to protect and connect the trees together into a functioning emergent superorganism that we call a “forest,” allowing for exchanges of information and nutrients across vast distances—and even between different plant species.
Without beneficial microorganisms, trees would wither and die or be attacked by pathogenic microorganisms. Without the tree root exudates, the fungi and bacteria would have no food. It’s mutualism at work, or perhaps more aptly: a collaborative regenerative economy.
Fact 3: Plowing & Tilling Soil Is Like Bulldozing a Human City
If you think of the planet as one giant emergent superorganism, then soil is akin to the “skin” of the earth.
What does your body do when you scrape off your skin? It forms a scab and starts repairing the skin.
What does earth do when we scrape off or plow the soil surface? It begins repairing its skin with “weeds” above ground, supported by a diversity of microorganisms below ground (initially dominated by bacteria).
As we discussed in #2 above, earth’s skin is constantly trying to return to a state of stability and health, which looks to our eye like a mature forest, tundra, grassland, etc—depending on the specific climate, geography/topography, and the creatures living above and below the soil surface.
Perpetual damage and injury…The above ground critter that has proven to be far and away the most destructive to soil and plant ecosystems is human beings. Using ever more brilliant and highly advanced technologies, we rip down forests in order to plant a few types of annual weedy grain plants to feed ourselves.
To maintain Stage 2-3 on the plant succession scale, we till the soil a few times per year, which destroys the complex cities/civilizations of microbial life that the soil once harbored, especially the vast networks of mycorrhizal fungi. We then add insult to injury by using:
a) Synthetic fertilizers
Fossil-fuel intensive synthetic nitrogen fertilizers which cause massive bacterial blooms in the soil that rapidly deplete the soil humus (aka carbon reserves), and rid the soil of the microorganisms responsible for naturally cycling nitrogen.
Our replacement nitrate inputs then wash through our dead soil and into our aquifers and waterways causing a wide range of human health and environmental problems. This point was hammered home by research conducted at the 100 year old Morrow Plots by University of Illinois soil scientists and has been supported by myriad other research around the world as well.
Another negative externality: our fertilizers actually cause our crop plants to be much more attractive to pest insects.
b) Synthetic pesticides
When our soils are no longer able to harbor living biological systems, we resort to the blunt, primitive tools of human chemistry to try to replace the functions that were once maintained by the biology we destroyed.
Without the protective and nurturing benefits inherent in a system with a high degree of “food web complexity,” systemic imbalances and overpopulations of pathogens and pests become the norm, not the exception.
Rather than addressing the problems we’ve created using biomimicry/agroecology, we often try to “fix” them with more/newer poisons, which create more negative feedback loops, which we then fix with more/newer poisons, which then… you get the point.
Image: How the nitrogen cycle works in a functional ecosystem. There is no such thing as “waste” here. Nothing is lost. Everything is reused. The same is true of the carbon cycle, the methane cycle, the water cycle, etc. Image credit: Cicle_del_nitrogen_de.svg: *Cicle_del_nitrogen_ca.svg: Johann Dréo (User:Nojhan), traduction de Joanjoc d’après Image:Cycle azote fr.svg. derivative work: Burkhard (talk) Nitrogen_Cycle.jpg: Environmental Protection Agency derivative work: Raeky (talk) – Cicle_del_nitrogen_de.svg Nitrogen_Cycle.jpg, CC BY-SA 3.0, Link
New York City was not built in a single year by a single person with a single skill set. Likewise, massively diverse sets of microorganisms are required to build the processes, structures, and networks necessary for healthy soil and plant systems.
If you remember one thing from this section, make it this: when the biology in your soil is tuned to the plants you’re growing, you don’t have to use synthetic fertilizers or pesticides.
Your soil microorganisms feed your plants the exact quantities and ratios of nutrients they need when they need them, and your plants feed and nurture the microorganisms in return. In addition, your plants benefit from heightened pest and disease-resistance. Predatory nematodes and fungi eat the root-eating nematodes; ladybugs eat the aphids; pathogenic fungi are kept away by endo and ectomycorrhizae fungi; etc..
Don’t believe us?
How do you think it is that a mature forest or grassland ecosystem grows stronger and more resilient each year with zero human input, but our industrial farms require constant inputs of fertilizers and poisons to produce a yield?
Fact 4: Restoring Global Soil Health Could Stop Climate Change
As we all sang in school, “In 1492, Columbus sailed the ocean blue!”
Image: Depiction of Columbus “discovering” the New World. He looks like a nice, friendly fellow! Image credit: L. Prang & Co., Boston – This image is available from the United States Library of Congress‘s Prints and Photographs division under the digital ID cph.3b49587. Public Domain, Link.
Columbus was no doubt brave and ambitious for making it across the Atlantic Ocean from Europe. However, his esteem has rightfully diminished in recent years as revelations of his and his men’s depravity emerged. Rape, murder, torture, slavery, and cutting off the ears and noses of natives was par for the course in their genocidal quest for precious metals and jewels.
Unbeknownst at the time, but Columbus and his men would also set off a chain of events that had a far greater global impact than what they could do with their own swords and matchlocks. As chance would have it, the Native American populations they encountered had virtually no immunity to the germs the Europeans brought with them.
Population collapse, ecological regeneration
Between 1492 and 1601, it’s estimated that up 90% of the human population in the Americas died from small pox and measles. (A relatively small number were killed directly by European invaders, although this should still be considered a genocide.)
Most native ethnic groups throughout the Americas practiced some form of agriculture. (Often their diets were heavily supplemented by hunting and gathering foraged foods as well.)
As their populations were wiped out by virulent European diseases, an estimated 50 million hectares of land soon progressed forward on the plant succession scale, returning to forest. For reference, 50 million hectares is about 200,000 square miles, an area larger than the entire state of California, which is about 158,000 square miles.
What impact did this depopulation event have? Trees and their symbiotic soil microorganisms took a giant collective breath in, removing and storing a massive quantity of greenhouse gases from the atmosphere and sequestering them in the soil microorganisms and to a smaller degree in the carboniferous structure of the trees/plants themselves.
Climatologists call this the “Orbis Spike.” Shortly thereafter, the earth entered the “Little Ice Age.”
So, germs carried by Christopher Columbus & Co killed the Native Americans which allowed forests to regrow which sucked in atmospheric carbon which caused a dramatic cooling of the global climate which resulted in mass havoc around the globe (including in Columbus’s home country Spain).
What Happened Next? What Happens Next? Choices…
You’re probably vaguely aware of what happened next: over the proceeding centuries, Europeans spread throughout the Americas. With the forced assistance of 28 million African slaves, they tore the forests back down and plowed the soils, re-releasing the carbon, methane, etc. back into the atmosphere.
What you’re probably not well-aware of is that — centuries later — we humans could use our newfound agricultural knowledge to actually stop global warming while also producing more than enough food to feed the world’s population far into the future. The bad news is that we’re currently taking the opposite approach and operating like ecological conquistadors.
As it turns out, soil contains more carbon than the atmosphere and all the vegetative matter on earth combined. Let us repeat that: soil contains more carbon than the atmosphere and all the vegetation on earth combined.
Interestingly, new research shows that certain types of symbiotic fungi—ectomycorrhizal and ericoid mycorrhizal (EEM)—can lead to 70% more carbon sequestration in the soil than other types of fungi. None of this information has been considered in current global climate models, so a great challenge for soil and climate scientists will be assessing precisely how much greenhouse gas the world’s soils might sequester under various management practices and farming systems.
This is where regenerative, organic agricultural practices come into play.
Yes, using holistic, ecologically-sound organic approaches, we can still grow our annual cereal crops at the same yield-per-acre AND without destroying/tilling soil, using synthetic nitrogen fertilizers, pesticides, and herbicides.
We can also utilize radically advanced, regenerative “forest agriculture” biomimicry approaches that are as cutting-edge today as they were thousands of years ago when humans first invented them. What we can’t continue to do is use the industrial, chemically-dependent, one-size-fits all model that is now considered “conventional” agriculture.
What about those terrible cows and other ruminants we grow and eat for protein? Used intelligently under Holistic Planned Grazing techniques—which would put an end to growing and feeding grains to ruminants on CAFOs—these animals can be as good for soil health and greenhouse gas sequestration as any other regenerative farming techniques.
The Heresy of Better Solutions
So why aren’t all biotech companies, conventional farmers, and policy makers making these things happen now?
This isn’t a new mobile app, machine or patentable biotechnology that’s going to bring wealth and/or power to a small handful of companies or superpowers. Hence, our westernized brains are going to have great difficulty understanding and/or implementing approaches that aren’t reductionistic and instead require holistic, systems-based collaborative thinking.
Also, entrenched interests rightfully feel threatened by these approaches. A novel, disruptive ecologically sane approach is bad enough on its own right. The fact that this approach has the potential to deleteriously impact our ability to extract money from modern slaves and the natural Commons while pumping that plunder to the top of a wealth pyramid is downright heretical.
Fact 5: Soil Is Our Most Precious Resource, and It’s Almost Gone
Alright, if you’ve made it this far, you now have some appreciation for how healthy, living soil is vital to you and the planet you call home.
President Franklin D. Roosevelt said it best: “A nation that destroys its soils destroys itself. Forests are the lungs of our land, purifying the air and giving fresh strength to our people.”
So how are we doing? Short answer: we’ve got a lot of thinking and working to do. And time is not our friend.
Half of the topsoil on the planet has been lost in the last 150 years. In the US, we lose 6 pounds of soil to erosion for each pound of food we produce.
Over the past 50 years, we’ve been able to get far larger yields of commodity crops per acre of land, but those yield increases have come at an enormous price: nutrient depletion, loss of microbial life, soil compaction, soil erosion, water pollution, carbon pollution, desertification, sedimentation/infill of waterways, increased floods, etc.
Nope, more chemical fertilizer and “icides” won’t help the problem; they’re one of the primary causes of the problem.
During the past 40 years, nearly one-third of the world’s cropland (1.5 billion hectares) has been abandoned because of soil erosion and degradation. –David Pimentel and Mario Giampietro, Food, Land, Population and the U.S. Economy
Don’t Soil Your Shorts Just Yet…
Now, we’re going to scare you, but don’t worry because we’re going to finish with some good news. In this fascinating interview with TIME Magazine, University of Sydney and Rothamsted Research’s Scientific Director Dr. John Crawford weighed in on our global, manmade soil problems:
“A rough calculation of current rates of soil degradation suggests we have about 60 years of topsoil left. Some 40% of soil used for agriculture around the world is classed as either degraded or seriously degraded – the latter means that 70% of the topsoil, the layer allowing plants to grow, is gone. Because of various farming methods that strip the soil of carbon and make it less robust as well as weaker in nutrients, soil is being lost at between 10 and 40 times the rate at which it can be naturally replenished. Even the well-maintained farming land in Europe, which may look idyllic, is being lost at unsustainable rates.
Final Thoughts: The Good News (and Some Homework)
Conventional wisdom says that it can take up to 1,000 years to form 1 inch of soil. This means it would take millions of years for nature to undo the damage we’ve done.
So is it time to get out our “end is nigh” signs and head to the street corner? We think there are more productive ways to address the problem than doom and gloom.
The rate at which soil is “naturally replenished” by nature operating on her seemingly slow, geologic timescale doesn’t mean we human beings can’t replenish our soil at far faster rates than natural processes would normally allow.
We don’t ever want to present a problem as big and scary as this one without concurrently presenting a solution…
This is where the good news comes in AND you get your homework assignment! At some point this evening or this weekend, we want you to take a few minutes to watch this presentation by one of our personal heroes; a person who is considered by many to be the world’s preeminent soil microbiologist, Dr. Elaine Ingham.
She’s not just an intellectual giant with good ideas, she’s actively working with small and large ecologically-minded farmers around the world to implement the solutions to our soil woes right now. And, yes, the information in this presentation will make you a radically better and more knowledgeable organic gardener or farmer:
We hope you enjoyed these FIVE AMAZING SOIL FACTS! We also hope you’ll consider improving some of your consumption patterns and perhaps even start your own organic/permaculture garden.