The Food Nightmare Beneath Our Feet: We're Running Out of Soil
By Larry Gallagher Ode April 28, 2010
Each year the world loses an estimated 83 billion tons of soil. What does this mean for food production and what can we do about it?
John Jeavons is saving the planet one scoop of applesauce at a time. Jeavons stands at the front of the classroom at Ecology Action, the experimental farm he founded on the side of a mountain above Willits, in Northern California’s Mendocino County. For every tablespoon of food he sucks down his gullet, he scoops up six spoonfuls of dirt, one at a time for dramatic effect, and dumps them into another bowl. It’s a stark message he’s trying to get across to the 35 people who have come from around the country to get a tour of his farm -- simplified, to be sure, but comprehensible: For every unit of food we consume, using the conventional agricultural methods employed in the U.S., six times that amount of topsoil is lost. Since, according to the U.S. Food and Drug Administration, the average person eats a ton of food each year, that works out to 12,000 pounds (5,443 kilograms) of topsoil. John Jeavons estimates that using current farming practices we have 40 to 80 years of arable soil left.
If you don’t already know the bad news, I’ll make it quick and dirty: We’re running out of soil. As with other prominent resources that have accumulated over millions of years, we, the people of planet Earth, have been churning through the stuff that feeds us since the first Neolithic farmer broke the ground with his crude plow. The rate varies, the methods vary, but the results are eventually the same. Books like Jared Diamond’s Collapse and David Montgomery’s Dirt: The Erosion of Civilizations lay out in painful detail the historic connections between soil depletion and the demise of those societies that undermined the ground beneath their feet.
According to the International Soil Reference and Information Centre (ISRIC), as of 1991, human activity has brought about the degradation of 7.5 million square miles (19.5 million square kilometers) of land, the equivalent of Europe twice over. The Food and Agriculture Organization of the U.N. has estimated that the value of lost soil nutrition in South Asia amounts to some $10 billion a year. Each year, says Montgomery, the world loses 83 billion tons of soil.
Still, these abstract facts have a way of eluding our comprehension. When we put a human face on them they begin to sink home. The U.N. Convention to Combat Desertification (UNCCD) has estimated that desertification in Sub-Saharan Africa will drive 60 million people from their homes in the next 20 years. While agriculture has thus far been able to keep pace with growing demand, it has done so by borrowing soil fertility from the future. But whether a global crisis is 20, 50 or 200 years away, the point remains the same: We as a species would be wise to take better care of our dirt.
In the hyper-abstracted economics of today, it is easy to forget that land is one of the irreducible foundations of all economies. As the world economy has deflated in the last year, it has driven many people all over the world back to earth, if only to grow a few tomatoes in their backyards. In 2009, the Associated Press reported a 19 percent increase in residential seed sales in the U.S., a bump known in the business as “recession gardening.” When the Obamas planted a garden on the White House lawn, it was at once an economic, environmental and spiritual gesture -- a nod, if nothing else, to the primacy of dirt.
Like most everybody else on our little planet, save for a few hunter-gatherers and breatharians, I have been a silent accomplice in this process. So I have decided to take matters into my own hands, largely figuratively and more than a little bit literally, and see what I can do to minimize my soil footprint. In the course of this exploration, I will follow my interaction with dirt as it moves in a cycle, through the food I eat, as that food leaves my body, and, ultimately, as I myself leave my body.
With this in mind, I made the pilgrimage up from San Francisco to sit at the feet of John Jeavons, who has probably spent as much of his life thinking about building soil as anyone who has ever lived. Jeavons started his career in the 1960s as a systems analyst at Stanford University. When the spirit moved him to pursue agriculture as a vocation, he brought that kind of analytical thinking with him. These are the questions that drove him: How many calories does a person need to survive? What is the smallest plot of land needed to grow those calories for one person for one year? How much land do we need to feed all the people on the planet?
Jeavons has devoted his career to answering these questions and spreading that information around the globe. A small but significant chunk of that learning can be found in his book How to Grow More Vegetables Than You Ever Thought Possible on Less Land Than You Can Imagine, first published in 1974, which has sold half a million copies and gone through multiple editions.
The premise from which Jeavons operates is that nearly all farming on the planet, be it organic or conventional, First World or Third, takes more than it gives. Most organic farming, for example, borrows soil nutrition, in the form of compost or manure that has been generated elsewhere. Jeavons’ standard for sustainable land stewardship proposes a very simple, obvious benchmark: It must generate at least as much topsoil as it uses. And as the world grows smaller and each scrap of arable land becomes less expendable, borrowing nutrition from some other piece of land is not solving the problem, he argues, but simply moving it around.
You can get much of this out of his books, but to get a direct transmission it helps to visit the farm when it is operating in full force. Ecology Action sits 700 feet (213 meters) up on the edge of a ridge, with a sumptuous view of the Willits Valley. There are many reasons Jeavons ended up on this particular plot of land, but none has to do with the quality of the soil, which was judged marginally acceptable for grazing when he picked it up in 1982. He enjoys working with the challenges of sub-optimal soil and limited sunlight, and is up-front about the fact that, by the standards of Grow Biointensive, as he calls his system, the gardens here are only moderately productive.
By the standards of the average visitor, however, the garden is exploding with life. Rye grass and Jerusalem artichoke wave across at beds of quinoa and amaranth. What looks like a casual paradise is actually a closely monitored science project. Every leaf that leaves the premises is weighed and recorded. Interns from around the world buzz through like bees, tending beds and fruit trees. The catch, if indeed it is a catch, is that Jeavons’ methods work best on a small scale, on relatively small plots of land, executed by people who are paying attention and care enough to expend the necessary labor. And while he believes his methods can be scaled up, his philosophy in general is that civilization needs to scale down, localize, put more elbow grease and less fossil fuel into the food chain.
At the heart of Jeavons’ system is a maniacal focus on composting. Now, when he uses the term he is not merely referring to the quaint re-circulation of leftover bits of lunch. Jeavons recommends that a gardener devote a full 60 percent of planting space to growing crops the principal purpose of which is to add biomass to compost piles. Cereal grains, giant overgrown daikon gone to seed and six-foot-tall (two-meter-tall) cardoons are among the many plants born to die and rot un-tasted, cut down and fed through the system, capturing more carbon with each generation.
On average, around the world, it takes 500 years for nature to produce an inch of topsoil. Number crunchers claim modern farming techniques increase erosion at 10 to 40 times the rate of nature. When his system is operating at peak productivity, Jeavons can grow food and increase topsoil at 60 times the rate of nature.
After I left Ecology Action, I began to see soil nutrition everywhere. The stalks of feral fennel growing in the middle of the road, the otherwise-useless clumps of bamboo decorating my front yard: All started looking like more carbon sources for my compost pile. A bushy tomato planted too late to fruit, a radish gone to seed -- what I used to see as gardening failures, I now see as dinner for the next generation of plants.
At 7:42 a.m. on Friday, in Vacaville, California, Truck No. 17246 backs onto the ramp at Jepson Prairie Organics and regurgitates its contents into a massive heap. The sight of a 24-ton trailer tilted up on end, spewing rotten vegetables, cardboard and yard trimmings into a small hill stirs me on many levels: mechanical, biological and olfactory. This is the first of some 400 tons of organic material hauled out from San Francisco each day and put through the composting mill. At the end of 60 days, most of the resultant matter will be trucked to vineyards in Napa and Sonoma counties. Some small percentage of it will make it to organic farms in the area.
Jepson is a subsidiary of Recology, the waste management company that hauls away my trash in San Francisco. The folks at the composting facility have worked too long tweaking their system to turn their secrets over to their competitors, so they’re cagey about revealing the details of their process. All you and I need know is that they sort, they grind and they blow the green waste into long windrows, which they aerate each day with a huge industrial windrow-turner. The combination of central valley sunshine and bacterial action helps get the row hot enough to break down in 30 days. The compost is given another month to cool and age before it is carted to its next destination.
Walking through the massive windrows, I get a chance to talk to Bob Shaffer, a composting guru who works as a consultant to both Jepson and the wineries who use its product. He’s been a student of the soil since he began gardening for himself 35 years ago. Shaffer explains it is not simply the sheer volume of soil that is at issue, but the quality of that soil. He gives me a quick lesson in soil mechanics: “Plants, in conjunction with microbes in soil, produce what are called polysaccharides. These polysaccharides can loosely be called gums, glues and gels. They stick the soil together, make it harder for water and wind to blow it away.”
The hidden story in farming, says Shaffer, is the decline of soil health in general. “It adds up over years and ends up in soil erosion,” he says, “kind of like the buildup to the dust-bowl. As the humus level -- the amount of the degraded organic material in the soil -- drops and drops, the polysaccharide content drops and drops, and finally the soil loses its ability to adhere and stay in place even if we have mulches and ongoing measures to prevent it.”
When I hear “dustbowl,” I tend to think of a past problem, sepia tints of Okies squinting in the wind. But China has been working on its own massive dustbowl for years, overgrazing and over-farming in fragile grasslands resulting in the displacement of millions of people and in annual dust storms that blow through Beijing like a plague.
Before things get to that point, Shafer says, more communities need to start closing the loop, to bring as much organic material as possible back to the farms. The Environmental Protection Agency estimates that nearly a quarter of all municipal waste comes from food scraps and yard trimmings. (Organics buried in landfills also generate methane, which is 23 times as potent a greenhouse gas as carbon dioxide.) “It’s not the whole solution,” he says, “but it’s a start.”