it ain't just dirt

This post is an excerpt from _A Nation of Farmers: Defeating the Food Crisis on American Soil_, by Sharon and I. You can find out more about the book by clicking here. The proof reading just came to a close and the book will be available very shortly. It occurred to me, while proofing reading the two sections that I'm about to post, that they describe our sad situation with regards to soil, the basis for life on this planet, and how we might turn around our treatment of this life-giving medium as we shift away from industrial agriculture. I thought those of you planning your gardens might want to know more about the community of life that makes up soil and how to foster this community.

The soil requires a duty of man which he has been slow to recognize.

—Henry A. Wallace

It’s fair to say that we’re picking on industrial agriculture here when poor practices of resource management have occurred throughout the history agriculture. What makes our most recent failure to manage our natural resources so scary is the scale at which we are failing. Hugh H. Bennett and W.C. Lowdermilk said, “Soil erosion is as old as agriculture. It began when the first heavy rain struck the first furrow turned by a crude implement of tillage in the hands of prehistoric man. It has been going on ever since, wherever man’s culture of the earth has bared the soil to rain and wind.” But soil loss and degradation are now happening at an alarming rate and they’re happening most dramatically here at home. Each year in the US we lose more than 1 million acres due to soil degradation, not to mention the 2 million more lost to land development.[i]

When examined more closely, the phrase “land development” seems to be a contradiction in terms—the development of land often results in the destruction of its capacity to produce food. Francis Moore Lappé et al. point out in World Hunger 12 Myths, that it is not in the underdeveloped global South where soil is being lost at the greatest rate. North America is now the continent with the most severe desertification problem. Since widespread farming began in the United States in the 18th century, an estimated 30 percent of total farmland has been abandoned because of erosion, salinization, and waterlogging. Fully one-third of the topsoil in the United States has been lost. Today about 90 percent of US cropland is losing soil faster than it can rebuild, and more than half of US pastureland is overgrazed and subject to high rates of erosion.[ii]

In this country we are losing soil 17 times faster than it can be replaced.[iii] In fact more than half of the incredibly rich Midwestern prairie soils that underlie the bread basket of the US, and indeed the world, have been lost to wind and water erosion during the past 100 hundred years.[iv] And now that this soil has been swept out to sea by the rivers and the streams of our nation, it will never be available to us for farming. How long will it take to wash away the other half?

It seems we’ve become very careless with our treatment of the soil here in the US, and sadly the same is true of the treatment of our soils worldwide. Almost sixty million tons of topsoil are lost each day. And this shouldn’t surprise us. Citizens in overdeveloped nations have supported the transformation of countless acres of poor-world subsistence farms and sustainably managed ecosystems into industrial farmland for the production of commodities for export. This means that many more people in the underdeveloped world find themselves unable to provide food and fuel for themselves. Sadly a feedback loop has been created whereby hungry people, in order to feed their families, destroy the soil that kept them from starvation. In other parts of the world, biomass, including trees, shrubs and other perennial plants, is stripped from large areas and massive amounts of soil are lost because of a shift in agricultural management practices, overgrazing and cutting for fuel to heat and cook.

This need for food and fuel, coupled with distorted economic priorities, which are often at odds with long-term security, results in massive soil loss in the developing world. Pressures from the developed world bear down to increase the destruction. Every year thousands of square miles of rainforest are cleared, much of it at the order of fast food companies like McDonalds (and by extension anyone who eats there) who need land over seas for cheap beef production. As Dr. M.E. Ensminger, former chair of the Department of Animal Science at Washington State University, says in Animal Science,

Is a quarter pound of hamburger worth a half ton of Brazil’s rainforest? Is 67 square feet of rainforest—an area about the size of one small kitchen—too much to pay for one hamburger? Should we form cattle pastures to produce hamburgers in the Amazon, or should we retain the rainforest and the natural environment? These and other similar questions are being asked too little and too late to preserve much of the great tropical rainforest of the Amazon and its environment. It took nature thousands of years to form the rainforest, but it took a mere 25 years for people to destroy much of it. And when a rainforest is gone, it’s gone forever.[v]

This is true all over the world as large land owners employ dubious land use tactics to displace small local land owners. In this case, those who recognize the value of soil and its potential to provide for those who know how to care for it are no longer in charge of the stewardship of this resource, having been replaced by multinational corporations with economic goals that supersede the care of this precious resource.

One might think the economic impact associated with soil loss might get their attention. The global loss of more than 75 billion tons of soil each year is worth $400 billion annually. US agricultural losses due to the need for irrigation and nutrient replacement associated with soil loss are estimated at $28 billion alone.[vi] And there are other costs too, described by Dale Allen Pfeiffer as,

the offsite costs of soil erosion: roadway, sewer, and basement siltation; drainage disruption; foundation and pavement undermining; gullying of roads; earth dam failures; eutrophication of waterways; siltation of harbors and channels; loss of reservoir storage, loss of wildlife habitat and disruption of stream ecology; damage to public health; and increased water costs.[vii]

But what makes this enormous loss of soil so alarming is just how long it took to create this precious resource. It takes more than 500 years in nature to build one inch of healthy topsoil,[viii] and it takes a minimum of six inches of soil to grow food.[ix] Much more is definitely desirable. That’s at least 3,000 years’ worth of natural soil building for the start to finish in an agriculturally productive land base. As Franklin Delano Roosevelt declared, “A nation that destroys its soil, destroys itself.”[x]

In recent years, chemical fertilizers and pesticides have in part compensated for the loss of soil humus, and we have been able to overlook lost soil productivity. As the feedstock for such chemicals becomes more costly and scarce, however, it is likely that we will experience the true extent of the damage we’ve done to ourselves through damage to our soils.

So what is the alternative? What cyclical model is available to us? Well, there is some good news. Though the process by which soils build up by breaking down organic material and eventually stabilize that material into what we call humus is naturally a slow one, it can proceed much more rapidly with active human participation. Historically most successful older societies have managed to avoid degrading their soils.

We work against nature by not returning organic material to the soil and we do worse with our practices that strip vegetation from the ground and cause erosion and with the poisonous chemicals we spray on our crops. We can, however, reverse this damage with healthy soil management practices and begin to build soil. Pesticides and concentrated chemical fertilizers damage healthy soil by destroying the microscopic life that makes up the soil; what soil is left after it is blown and washed away through poor cultivation techniques. So the first step is clearly to stop these practices, to add organic matter, to end tillage, not by pouring on more Round Up but by making use of organic strategies for sustainable planting.

This means cultivating small plots of land with a much more hands-on approach. Turning under thousands of acres at a time with enormous earth-churning machines should give way to increasing the amount of food we grow with practices of reduced tillage or no-till strategies. By this we do not mean the drenching of soil with herbicides and planting resistance crops into the ground—that is what many people mean when they speak of zero-tillage. But as the Rodale Institute has found, organic no-till agriculture can outyield both conventional chemical no-till and conventional tilled organic practices.[xi]

The healthy soil of a carefully managed quarter-acre Victory Garden can be administered easily with a shovel and a hoe. Water and wind erosion can be almost eliminated, and organic material in the form of compost and manure can be used to maintain soil health and fertility. For larger farms, the use of crimper and other tractor or horse attachments can minimize erosion, and the returning of manures to soil can improve humus levels. Using other strategies like compost teas and manure teas can result is a bloom of micro fauna that helps to repopulate barren soil with its natural inhabitants and fertilize it in a more natural way.

We have wasted much that nature can do to aid us in food production in chemical agriculture. Pesticides and chemical fertilizers destroy the community of living soil. The top six inches of soil is the most densely populated ecosystem on the planet. It is a mysterious world of micro and macro fauna that recycles the dead and provides for the living. It is this subterranean community that we all depend on for our survival. Permaculturalist Scott A. Meister points out, “In fact, there is more life below the surface of the earth, than above it.” He says of healthy soil,

It’s important to have soil biota such as microflora and fauna (bacteria, fungi, actinomycetes, and algae) micro, meso and macro-fauna such as centipedes, worms and termites. These soil biota are the managers, or underground stewards of the earth. Some serve as highway makers, others as transporters, others act like the underground internet. Termites and ants are the earthmovers, as well as digesters and soil makers. Worms, specifically, break down organic material into smaller forms that can be digested by the smaller beings such as bacteria and fungi, in order that the minerals can be more easily taken up by plants. Worm castings (worm poop) are nature’s best fertilizer, and worms can create 60 tons of worm cast per acre per year.[xii]

We must regain respect for the well being of this community and foster its health if we are to return to a sensible way of growing food.

Beyond fixing soil is the more basic task of maintaining the fertility of the soil that remains and fully returning to the practice of sustainable soil management. John Jeavons, author of How To Grow More Vegetables and the man largely responsible for popularizing the form of French intensive gardening in this country, suggests that to farm sustainably in a biointensive manner—a manner that produces a lot of food in a relatively small amount of space—requires that 60 percent of all gardened areas be devoted to growing compostable crops. These crops, which include grains, also produce food, but much of their value is in the fertility they provide—this means a new way of looking at our food crops. In other words, he says that more than half of all the plants we actively grow under such a system should be put back into the ground in an effort to feed the soil. It is possible to work with nature to speed up the process of soil formation through processes like growing crops for compost and recycling the carbon and nitrogen in fallen leaves and other discarded plant material, as well as food waste, in an effort to increase the amount of healthy soil available for agricultural production.

However, our ability to foster healthy soils will go beyond the support of sustainable agricultural practices. Not only will we need rich soils to feed the growing population of people on this planet but soil building might also become a major tool in our effort to stabilize atmospheric levels of carbon and combat the climate change associated with global warming.

Francisco de Orellana, a Spanish conquistador who explored the Amazon River basin in the 16th century, spoke of a vastly populated region thought by most modern historians to have supported only sparse numbers of humans. The reason for this was that it was assumed that because tropical rainforest have notoriously poor soils it was unlikely that such soils could support high numbers of humans.

Recently however, archeologists have made a discovery that might support Orellana’s report. It appears that coexisting groups of Amazon inhabitants from 400 to 1200 ad utilized a soil-building technique that resulted in terra preta or “black earth”—a type of soil made up of plant and animal remains mixed with charcoal. The result was an astoundingly fertile soil that could have supported many more inhabitants through increased agricultural yields than the sparse population in the Amazon basin previously estimated by researchers. Michael Tennesen, writing for Discover, goes on to explain,

As thrilling as this evidence is to archaeologists, it may also have very practical importance as a modern weapon against some of our most urgent ecological problems. Soil scientist Johannes Lehmann of Cornell University believes that the mysterious dark earth holds clues to creating sustainable farming practices and even to combating global warming.… First, because the enriched soil remains fertile for a long time, its use would discourage farmers from moving on and burning more forest to open up new fields. Second, because of the added charcoal, terra preta holds up to 10 times as much carbon as unaltered soils. The late Wim Sombroek—a legendary soil scientist whose long interest in terra preta earned him the epithet “the godfather of dark earth”—began to wonder if dark earth could be used to sequester carbon. Lehmann’s studies have shown that it can: Fifty percent of the original carbon in plants and trees used to make biochar remains in the terra preta soils after the conversion.[xiii]

So it appears that a low-tech alternative such as adding charcoal to our soil could work not only to repair depleted soils but also help with some of the much needed work of sequestering carbon. That is, there are ways in which we can revitalize the soil and thus avoid the false choice of making it temporarily productive with hydro-chemical concoctions or simply stopping such fertilization efforts and starving to death.

And there is more good news about how our ability to help recreate healthy topsoil and sequester carbon can further help. Joel Salatin operates Polyface Farm a “family owned, multi-generational, pasture-based, beyond organic, local-market farm and informational outreach in Virginia’s Shenandoah Valley.” His strategy of pasturing animals relies on perennial grasses in a rotating system. The grasses feed cows, who then move on to other pastures. Chickens are then allowed to follow the cows to pick through the manure and graze on the grass not eaten by the cows. The combination of cow and chicken manure fertilizes the grasses, which are then allowed to regrow before the pasturing cycle is repeated. The fields are never tilled. This might sound like a simple, unimportant description of farm animals being raised for meat, but it isn’t.

Peter Bane, editor of Permaculture Activist, describes the possibility in an article entitled, “Storing Carbon in Soil: The Possibilities of a New American Agriculture.” After hearing Salatin describe his 500-acre farm in the Shenandoah Valley in Virginia and its soil-stewardship practices, Bane was moved to do some math. Salatin said that in 1961, when his family first arrived on their current plot of land, soil testing revealed 1.5 percent organic matter. A subsequent test in 2007 revealed 8 percent.

In 46 years of rotational grazing without the addition of any fertilizers except composted manures from the animals’ winter bedding (supplemented with woodchips and other carbon from local sources, but minus the animals that leave the land), Polyface has built up 6.5% additional carbon in their pasture soils while taking a profitable return from the sale of meat. They use essentially no toxic inputs, and need very little machinery…. An acre of soil covers 43,560 square feet. The top six inches, which is where most of the carbon is stored, weigh about 1900 tons per acre. The annual increment of increase in soil carbon at Polyface is 0.14%, about 2.7 tons per year.… A [more?] reasonable estimate of land [agricultural land in the US] with more than 30 inches of rainfall per year (the average in the Shenandoah Valley is 32" per year) is 800 million acres. That’s about 2/3 of the area east of the Dakotas, roughly from Omaha and Topeka east to the Atlantic and south to the Gulf of Mexico. It’s mostly growing corn and soybeans now, and they are mostly going to animal feed or industrial uses: paint and ink ethanol, fizzy drinks, and junk food, none of which is good either for people or livestock. If that land were farmed as the Salatins farm Polyface in Virginia, it could sequester 2.2 billion tons (2 billion metric tonnes) of carbon per year. That’s equal to present gross US atmospheric releases, not counting the net reduction from carbon sinks of existing forests and soils.[xiv]

Bane goes further to suggest that if carbon is traded at $50 per ton, such a shift represents a $100 billion boon for American agriculture. “Who needs subsidies from Washington?” he adds.
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[i] Pfeiffer, p. 13.

[ii] Lappé et al., p. 45.

[iii] Pimental Journal of the Environment, Development and Sustainability, Vol. 8, 2006.

[iv] Pfeiffer, p. 12.

[v] M.E. Ensminger, Animal Science, Prentice Hall, 1990, p .21 .

[vi] R. Lal, “Soil Erosion Impact on Agronomic Productivity and Environment Quality,” Critical Reviews in Plant Sciences, 17, 1998, pp. 319–464.

[vii] Pfeiffer, p. 16.

[viii] Pimental and Giampietro, Food, Land Population and the U.S. Economy, http://dieoff.org/page40.htm (accessed Nov. 25, 2008).

[ix] David Pimental. et al., “Will Limits of the Earth’s Resources Control Human Numbers?,” Environment Development and Sustainability, Issue 1 1999, p. 4.

[x] Letter to all State Governors on a Uniform Soil Conservation Law, February 26, 1937

[xi] http://www.newfarm.org/columns/research_paul/2007/0107 /notill.shtml (accessed Aug. 25, 2008).

[xii] http://permaculturetokyo.blogspot.com/2007/02/healthy-life-from-healthy-soil.html (accessed Aug. 25, 2008).

[xiii] Michael Tenneson, “Black Gold of the Amazon,” Discover, April 2007, http://discovermagazine.com/2007/apr/black-gold-of-the-amazon (accessed Nov. 25, 3008).

[xiv] Peter Bane, “Storing Carbon in Soil: The possibilities of a New American Agriculture,” Permaculture Activist, Autumn, 2007.