Table of Contents
"Soil" may be only slightly fancier a term than "dirt", but the upgrade in dignity is merited. Whatever you want to call the stuff that carpets the planet, it is vitally, fearsomely important to the future of the human species. And right now the world's topsoil is being treated like dirt.
Dirt. Eeew! But "Topsoil"? Okay...let's Talk.
What is topsoil anyway? Like ... pulverized rocks? Whatever it is, it's a dull subject -- until tracked into the house as garden-variety dirt, whereupon there is angry yelling from parent types. (I know -- I'm one of them). Yeah, our food grows from dirt (both meats and veggies, necessarily); but it's just ... dirt. Of course stuff grows out of it! What's the big deal?
But call the stuff "topsoil" and you have quietly changed the tenor of the subject. "Dirt" may be a hassle, and the scourge of your snowy white Jack Purcells®, but topsoil gives life.
Globally, 95% of our food grows from, and depends on, this topmost layer of dirt1. But lock-step farming practices over the past 50 years or so have been fixated on a forward-marching cycle of ever-increasing yield. "Grow or die" seems to be the unquestioned mantra, from corporate America to the beleaguered family farm.
As bio-engineering and chemistry have fulfilled the early promise of ever-increasing food crop yields (produced with the ostensible goal of feeding a swelling global population) our topsoil has become truly screwed.
Our Topsoil Has Become Truly Screwed
Our topsoil—the world's topsoil—is exhausted. How does soil get exhausted? The same way all of us do. Soil isn't just a dead substrate to throw seeds at. Stuff grows out of soil because soil is alive and seething with organic chemistry. How alive is soil? Okay -- it's been estimated (by the sort of 'numbers people' we can trust with this jazz) that all the people who have ever lived upon the Earth number about 117,000,000,000,000 (117 billion)2. Two hefty handfuls of healthy soil contain just about that many living microorganisms.
But our zeal to increase yield, efficiency, and profits has distracted us, lethally. Our topsoil is leaving us, and it's not always a story of chemistry being wantonly sprayed all over everything. Topsoil is under a double threat -- on the one hand it has been chemically overworked — all but stripped of life energy by decades of well-intentioned experimentation and lab-based productivity boosts.
On the other hand, our compromised topsoil can barely clutch the Earth any more and is being blown all to hell by the elements; scattered by the wind and washed away by the rain. There are farming traditions, we're discovering, that are better left behind.
Tilling a crop field -- turning the soil over in prep for next season's planting, a familiar and almost comforting visual trope — so loosens the soil it becomes vulnerable to being blown away by wind, washed away by rain.
Turning the soil that way is also like uprooting a major metropolitan city and sending its inhabitants naked into the countryside. Constant churning of the soil exposes, to above-ground elements, the heavily interdependent microbial life and biochemistry that undergirds the nutrient-infused character of soil.
One practice that is gaining traction with smaller farms is that of using cover crops3 to hold a field in place between growing seasons. The cover crop protects the soil by busying it with living vegetation when it would otherwise be fallow and tilled, and awaiting next season's planting. The cover crop, typically a grass, or clover, or alfalfa, absorbs the impact of falling rain and otherwise prevents the exposed soil from being blasted by the elements.
And because the soil is engaged with the living cover crop, it's acting like healthy and purposeful soil; sequestering CO2 from the atmosphere and directing it to spur and fuel organic dynamism in the soil, which the cover crop keeps vitally alive. The cover crop also keeps the soil supple and "fluid" so it doesn't become course and clotted for the coming food crop. The cover crop gives its all to maintaining a home for the crazily diverse microbiome that is indispensable to making food grow.
One odd citizen of the microbiome is mycorrhizae fungi4, which benevolently invades the root system of a plant to bring it more water and nutrients. What does the fungus get out of the deal? The plant hands the fungus all the photosynthesized carbohydrates it can eat. This is classic symbiosis -- two ancient pals keeping each other fed and watered through countless eons.
Cover crops are incorporated into the soil before they mature, adding an element of green compost to the coming food crop. No-till practices are already being implemented in about 51 percent of soybean, cotton, corn and wheat grown in the U.S.5
Cover crops, though, are only used in about 5 percent of U.S. crops.
Fertilizer and Weed Killer: A Feedback Disaster
When World War 2 ended we had more nitrogen than we knew what to do with. Nitrogen had been a key ingredient of the explosives we were using in the war. When the conflict ended, the issue turned from "what do we need to blow up?" to "how are we going to feed a decimated Europe?"
Nitrogen fit almost too neatly into its new mission of fomenting a generation of desperately needed food crops. The wrecked European continent was starving on its feet and we had the capacity, the materials, and the ingenuity to devise new methods of expanding food crop production to meet the need.
Farmers jumped at the chance to partake of these new postwar agricultural practices. The horrors of the 1930s Dust Bowl, in which drought burned and then howling winds scattered hundreds of thousands of acres of dead topsoil, were still fresh in their minds.
Green Revolution's Ominous Legacy
The new nitrogen-based chemical fertilizers were lavished on the food crops. The resulting plants grew so plentifully and so lushly, this agricultural epoch came to be called the Green Revolution—so seemingly successful was science in vanquishing hunger and rejuvenating America's farmers.
But wave after wave of nitrogen and phosphate-boosting produced crops that were a nutrient-compromised shadow of their former selves; a deficiency initially obscured by the incredibly robust volume of production, and the use to which it was put feeding millions of the postwar hungry.
But comparing the nutritional content of our food crops between 1950 and 1999 leaves no doubt about the steady nutritional decline of these agricultural products4-1. Our excited optimizing of agriculture brought a sort of blight to our foodstuffs; the blight of a hollowed out nutritional profile.
When the compromised plants couldn't defend themselves from sub-soil predators, pesticides were developed to take care of that issue, with the result that a new vanguard of crops evolved that were actually fertilizer and chemical- dependent5. Meanwhile, the chemicals—all harmless to humans, we were told— seeped into the groundwater and evaporated into the air.
Today these chemicals are woven inextricably into the fabric of our living ecosystem. If we stopped using these chemical stimulants and weed killers today (unlikely given the $57.2 billion global market for nitrogenous fertilizers), it's been estimated it would take some 50 years for the topsoil to rebound.
Back to Basics: Save our Topsoil
Throughout these decades of chemically ramped-up food production, the topsoil has become little more than a half-living matrix for growing nutritionally compromised plant matter.
Most ominously, certain measurable epidemics of dementia, and Parkinson's disease—to name three disorders whose incidences massively spiked—seemed to coincide with introductions of new weed-killing chemicals in the ag marketplace6.
We don't need to reinvent agriculture, we need to de-invent it—get back to when watching grass grow was an exercise in boredom, and not a mechanized war with nature herself. Now ... repeat after me: "Dirt Rules".