Also see:  Sustainable Community Development | Prime Directive | What is Meant by Development | Choice of Lifestyle | Institutionalized Resistance | Social Service | Hydrological Continuum | The Hidden Domain of Soil | My History in Sustainable Community | Educating for Sustainability | Giving Children a Voice

We shall not cease from exploration. And the end of all our exploring will be to arrive where we started and know the place for the first time.—T. S. Eliot


Chris Maser

"We belong to a mystery that will never belong to us," says poet John Daniel, "yet it is freely given to all who desire it. Though we distance ourselves, and fail to see, it is granted everywhere and all the time. It does not fail us [although we may fail it]." Soil is a part of the vast mystery to which we belong. "To forget how to dig the earth and tend the soil is to forget ourselves," wrote Mahatma Gandhi.

Many cultures have emphasized the trusteeship of the soil through religion and philosophy because it is the crucible in which the non-living and living components of life are joined to form the great "placenta" of the Earth. The biblical Abraham, in his covenant with God, was instructed:  "Defile not therefore the land which ye shall inhabit, wherein I dwell."¹ The Chinese philosopher Confucius saw in the Earth's thin mantle of soil the sustenance of all life and the minerals treasured by human society. A century later in Greece, Aristotle thought of soil as the central mixing pot of air, fire, and water, which formed all things.

In spite of the durability of such beliefs, most people cannot grasp their profundity because the ideas are intangible on the one hand and the march toward specialization increasingly isolates us, the "modern human," from Nature and our place in it on the other. The apparent invisibility of the soil stems from the fact that it's as common as air and, like air, is a birthright belonging to everyone, so no one, and thus is taken for granted.

For example, the Federal Bureau of Soils stated in 1878 that:  "The soil is the one indestructible, immutable asset that the nation possesses. It is the one resource that cannot be exhausted." While to many people soil seems "invisible" and thus indestructible, it's a seamless whole—the complexity of which is all but unknown even to soil scientists. "Each soil," says author Hans Jenny, "is an individual body of nature, possessing its own character, life history, and powers to support plants and animals."

Although soil seems "invisible" and thus indestructible to many people, it's a seamless whole that's all but unknown in its complexity, even to soil scientists. Whether most people understand it or not, soil is important for at least seven reasons:  First, soil is the repository of life and, as such, is the stage upon which the human drama and its many constructs are physically supported and played out. Second, soil plays a central role in the decomposition of dead organic matter, and in so doing adds to its store of potential nutrients. Third, soil stores elements that, in the proper proportions and availability, act as nutrients for the plants growing in it. Fourth, soil shelters seeds and provides physical support for their germination and roots as the plants grow and mature into adults, which produce seed and so perpetuate the cycle. Fifth, soil is the nursery for spores of the microbes, as well as decomposer and mycorrhizal fungi, that latter of which nourish the myriad plants. Sixth, soils of various kinds, acting in concert, are a critical factor in regulating the major elemental cycles of the Earth—those of carbon, nitrogen, sulfur, and so on. And seventh, soil both purifies and stores water.²

Human society is inextricably tied to the soil for reasons beyond measurable riches, for the wealth of the Earth is archived in soil, a wealth that nurtures culture even as it sustains life, as illustrated by the following quotes: "The social lesson of soil waste is that no man has the right to destroy soil even if he does own it in fee simple. The soil requires a duty of man, which we have been slow to recognize" (H. A. Wallace, 1938). "In the old Roman Empire, all roads led to Rome. In agriculture [and forestry] all roads lead back to the soil from which farmers [and those in the forestry profession] make their livelihood" (G. Hambrige, 1938).

Whereas both of these statements are as true now as the day they were uttered, it is the doom of people that they too soon forget. For example, nearly twenty percent of the vegetated surface of the Earth had already been degraded by human activities more than a decade ago,³ and modern technology in the form of machines and chemicals, if not wisely used, increasingly enables humanity to accelerate that degradation much faster than Nature can heal the old soil or create that which is new. "Obviously, agriculture involves the rearranging of nature to bring it more in line with human desires," asserts ecologist and author Donald Worster, "but it does not require exploiting, mining, or destroying the natural world."

Looking at the clod of soil, I see tiny sparkles as a few of the larger, individual particles reflect the sun's brilliance off their facets. And it occurs to me that poet Robert Blake's insight is correct—each grain of sand, each particle of soil does indeed reflect the universe, not only by tossing back a glint of the sun by day and the soft light of the moon by night but also by its long history through the atomic interchange.

The atomic interchange of soil is the result of two opposing geological forces—the fiery volcanism that builds mountains and the erosive powers that work to level them. As a volcano is built by fire from within, so it is eroded by wind, water, and ice from without. It defies gravity in its growing and falls to gravity in its dying. As with all mountains, volcanoes are "born," "die," and return, in concert with the creative novelty of all "living" things on Planet Earth, to the Great Mystery from which they came.


Soil is a combination of four main components:  minerals, water, air, and organic material. Sand, silt, and clay are the three basic building blocks of soil, whereas the water within a soil system dissolves the minerals, which constitute the primary source of nutrients for the plants. Air in the soil is needed for plant respiration and for microorganisms to obtain oxygen.

Although soil is derived from the minerals in rocks, termed "parent materials," laid down by the geological processes, as well as water and air, it is built up and enriched by the plants that live and die in it. It is further enriched by the animals that feed on the plants, void their bodily wastes, and eventually die, decay, and return to the soil as organic matter, such as little "humpety-backed" springtails and earwigs with their terminal "prongs." 
Springtail Earwig

Soil, the properties of which vary from place to place within a landscape, is by far the most alive and biologically diverse part of terrestrial ecosystems. The processes whereby soil develops are divided into two categories of weathering, physical and chemical, both of which depend on:  (1) properties of the "parent" rock, such as its physical and chemical composition; (2) patterns of regional and local climate; and (3) the kinds of organisms that are available and capable of becoming established in the newly forming soil, wherein they add organic material.

Physical Weathering:  Physical weathering refers to the mechanical fragmentation of rock through the actions of freezing and thawing, wetting and drying, heating and cooling, and/or transportation by wind, water, or ice.

Chemical Weathering:  A rock's primary mineral composition reflects the temperature, pressure, and chemical makeup during its formation, often at a high temperature deep within the Earth. At the Earth's surface, where temperatures and pressures are lower, water and various inorganic and organic acids, as well as other chemical compounds, mediate a tenuous state of ever-changing balance. As rocks adjust to the environment at the Earth's surface, the primary minerals may be transformed into secondary minerals through chemical weathering.

Minerals weather at different rates, depending on their chemical composition and crystalline structure. Small pieces of rock and small grains of mineral break down more rapidly than large ones because small ones have a much greater surface area compared to their mass than do big ones. For this reason, a particular rock may be more susceptible to physical decomposition than to chemical decomposition. Nevertheless, initial weathering, aided by bacteria and "rock-eating" fungi, must precede the formation of soil from hard rocks. Once soil is formed, however, the intensity of chemical breakdown is generally greater in the surrounding organic matter of the soil than in the rock itself.

The Addition of Organic Material to Mineral Soil:  One of the first recognizable manifestations of organic material in soil is the formation of a dark layer near the soil's surface. This organic material comes from bacteria, fungi, lichens, arthropods, and higher plants, such as grasses and herbs capable of becoming established in raw, mineral soil. In fact, their presence greatly increases the rate at which soil is formed because they not only add to the organic layer but also act as catalysts for chemical reactions.

There are distinct differences, however, in the distribution of organic material in soils. These differences depend on climate, slope, and the type of vegetation growing on the site, as well as the activities of animals. As might be expected under this scenario, soils of grassland and prairie contrast distinctly with those of a forest in the way they process and distribute organic material.

In the mid-western United States, for example, oak forest and prairie coexist in distinct patches under a similar regime of climate. Both types of vegetation have a similar amount of organic material, which includes live vegetation, vegetative litter on the surface of the soil, and organic material within the soil. But in the oak forest more than half the total organic material is tied up in the trees aboveground, whereas ninety percent of the organic material in the prairie is found within the soil.

As organic material is decomposed, it passes through many forms, but in the final analysis usually ends up as carbon dioxide, which is released back into the atmosphere. There are, in addition to the atmospheric releases, some relatively stable carbon compounds known as "humus," which lend soil its dark color. The decomposed organic material that lends soil its dark color is termed humus, the Latin word meaning "the ground, soil" or alternatively the New-Latin word humos, which means "full of earth."

Incorporation of organic material into the surface of the soil, where the dark layer of "topsoil" forms, is rapid when considered in the scale of geological time—but exceedingly slow when considered in the scale of a human life. Be that as it may, as organic material increases in mineral soil, so generally does plant growth.

Molecules of humus also act as weak acids and produce the "glue" that aggregates particles of soil to form its structure, such as the pores, that allow microbiological activity to exist, as well as the infiltration of water, which flushes carbon dioxide from the soil and allows oxygen to fill the pores. The porous nature of the soil provides a mechanism for holding in place oxygen, water, and chemicals that are required for chemical interactions. In fact, the cycling of carbon through soil influences both the speed with which water can infiltrate it and how long the water can be stored before plants absorb it and "transpire" (a plant's version of "perspiring") it back into the atmosphere. In addition, soil quite literally resembles a discrete entity that lives and breathes through a complex mix of interacting organisms—from viruses and bacteria, to fungi, to earthworms and isopods (such as sowbugs), to moles, gophers, and ground squirrels. In essence, soil is perhaps the most alive part of the Earth's terrestrial habitat. Sowbug.

The activities of all these organisms in concert are responsible for developing the critical properties that underlie the basic fertility, health, and productivity of soil. The complex, biologically driven functions of the soil, in which soil organisms are the regulators of most processes that translate into a soil's productivity, may require decades to a few centuries to develop. And there are no quick fixes if soil is extensively damaged during intensive agriculture or intensive forestry—even by something as simple as soil compaction.

The compaction of soil has a negative array of cascading, cumulative effects that range from decreased air and water in the soil itself to killed roots, slowing the growth of plants, suppressing the growth of mycorrhizal fungi, increasing the mortality of micro flora and fauna—all of which reduces the productive capacity of the soil. Although soil appears to be a solid substance composed of inorganic and organic matter, which you can hold in the palm of you hand and roll around between your fingers, it's much more than that.

Healthy soil has spaces filled with air between the particles and chunks that comprise its matrix. These pockets of air are created by all the organisms living in the soil, which range from microbes to larger animals, as well as fungi and the roots of plants. Most of these organisms depend on the availability of air and water moving through the soil in order to perform their vital, ecological functions that, in concert, create and maintain the soil's health and so that of field and forest. In this sense, healthy soil acts more like than a sponge than a brick because air normally constitutes half or more of its total volume.

To clearly understand this, fill a gallon pail with intact soil from a field or forest, where no machinery has been used. If you then compress it, you will find that at least half of the volume was air. Just as we humans require air to breathe, so does every living thing in the soil. Clearly, therefore, compacting the soil, which eliminates the air and thereby increases the soil's density, is suffocating to everything that must breathe in order to live.

Compaction of soil also reduces its ability to absorb and store water, which simulates a drought for those organisms that do survive the initial compression of their habitat, particularly in fine-textured clays and silts. Over time, compacted soil is more prone to actual drought than is healthy, friable soil.⁴


Organisms in the soil, such as bacteria, fungi, one-celled animals called protozoa, and worms, mites, spiders, centipedes, and insects of all kinds play critical roles in maintaining its health and fertility. These organisms perform various functions in the cycling of chemicals required as nutrients for the growth of green plants. Some of these functions are: (1) fixing nitrogen, which is the conversion of elemental nitrogen from the atmosphere by certain bacteria into organic combinations or forms readily usable in biological processes; (2) decomposing (recycling) plant material by bacteria and fungi; (3) improving the structure of the soil by such organisms as certain fungi that form a symbiotic relationship with the roots of certain plants—mycorrhizae—and produce a substance called "glycoprotein" (glomalin) and so increase soil aggregation;⁵ (4) mediating the soil's pH, a determinant of what plants and animals can live where and what chemical reactions can take place where; and (5) controlling disease-causing organisms through competition for resources and space. Without the organisms to perform these functions, the plant communities we see on the surface of the Earth (including agricultural fields) would not exist.

As the total productivity of an ecosystem increases, the biological diversity within the soil's food web also seems to increase and vise versa. As the number of interactions among decomposers (organisms that decompose organic material), their predators, and the predators of the predators increases, so do the nutrients retained in the soil as they cycle and recycle through the organisms.

It is only through this belowground food web that plants can obtain the nutrients necessary for their growth. Without the belowground food web, the aboveground food web—including us humans—would cease to exist.

Due to the ever-changing complexities of soil, we humans would be wise to develop the humility necessary to accept that we will never fully understand it; only then will we have the requisite patience to protect the organisms that perform the functions through which soil is kept healthy. Soil health cannot be maintained through applications of inorganic fertilizer, which not only disrupt the biophysical governance of the soil's infrastructure but also "addicts" soil to the petrochemicals in order to grow the desired plants. Moreover, much fertilizer may be lost as it leaches downward through the soil into the groundwater, which it then contaminates, because neither the soil nor the organisms in the soil's disrupted food web can retain all of the added chemicals, such as nitrogen.⁶ "Once polluted," admonishes ecologist and author Eugene P. Odum, "groundwater is difficult, if not impossible, to clean up, since it contains few decomposing microbes and is not exposed to sunlight, strong water flow, or any of the other natural purification processes that cleanse surface water."

In some cases, adding fertilizer even acts like a biocide, killing the organisms in the soil's food web, thereby further degrading the soil. It's therefore much wiser to work in harmony with the soil and the organisms that govern its infrastructure because they are responsible for the processes that provide nutrients to the plants.

The development of soil depends on self-reinforcing feedback loops, wherein organisms in the soil provide the nutrients for plants to grow, and plants in turn provide the carbon—the organic material—that selects for and alters the communities of soil organisms. One influences the other, and both determine the soil's development and health.

Although the soil food web is a prime indicator of the health of a terrestrial ecosystem, soil processes can be disrupted by such things as:  (1) decreasing bacterial or fungal activity, (2) decreasing the biomass of bacteria or fungi, (3) altering the ratio of fungal to bacterial biomass in a way that is inappropriate to the system, (4) reducing the number and diversity of protozoa, and (5) reducing the number of nematodes (roundworms as opposed to segmented worms, like earthworms) and/or altering their community structure.

A model of a soil food web, composed of interactive strands, is enlightening because it shows there are higher-level predators in the system whose function is to prevent the predators of bacteria and fungi from becoming so abundant they alter how the system functions. In turn, these higher-level predators serve as food for still higher-level predators. For example, mites, predatory roundworms, and small insects are eaten by organisms, which spend much of their time above ground. Similarly, predators in the third, fourth, and fifth upper strands of the food web are eaten by spiders, centipedes, ants, and beetles; that in turn are eaten by salamanders, birds, shrews, and mice; that in turn are eaten by snakes, still other birds, weasels, foxes, and so on.

With this view, it stands to reason that if part of the belowground biological diversity is lost, the soil as a system will function differently and may not produce a chosen crop in a way that meets our expectations (economic or otherwise) or may even produce a plant community not to our human liking, such as field of "weeds" instead of a commercially valuable crop. Should the predators in the soil be lost, which disrupts its governance, the mineral nitrogen in the soil may be lost, which in turn may cause poor growth in the plants and so the production of few seeds. Conversely, too many predators can overuse the bacteria and fungi, which results in slower decomposition of organic material that is needed to fuel the system of nutrient uptake by the plants. A reduction or loss in any part of the food web affects at least two strands of the web at other levels.⁷


Now let's consider soil from the "eye" of a bacterium to the infinity of space. The dimension of scale is important, because it adds greatly to our perception of diversity in the landscape that supports our agricultural fields and tree farms, as well as our perception of the way one part of the landscape relates to another. And both perceptions are necessary for us to make the wisest possible decisions concerning the best use of such things as our backyard gardens, agricultural fields, and national forests.

Scale is a progressive classification in size, amount, importance, rank, or even a relative level or degree. When dealing with diversity, however, we often overlook space or distance as a dimension of diversity.

Space and distance as a scale of diversity is right in our own backyard—and always has been. If, for example, you study a pinch of soil through a high-powered microscope, you will see things that you never imagined to be living in your backyard, but you cannot see the roses or even your house as long as you focus your attention into the microscope.

If you use a ten-power hand lens to look at the same pinch of soil, you cannot see what you saw through the microscope, but you can see more of the way the particles of soil and some of the larger soil organisms, such as oribatid mites, relate one to another. But as long as you are looking through the hand lens, you still cannot see the roses or your house. Oribatid mite

On the other hand, if you put the pinch of soil back where you got it, stand up straight, and look down, you have still a different scale of diversity. Now you see a wider patch of soil, but without the detail. If you climb onto the roof of your house and look down on the patch of soil, you now see even less detail of the soil, but you see the roses growing out of the soil, and you see your house. Imagine, therefore, what you would see if you hovered in a helicopter 100 feet, 1,000 feet, or 10,000 feet above the patch of soil in your backyard. What would you see from a satellite in outer space?

Let's look for a moment at the scale of distance and space in still another way. What would you see in your backyard if you were a microorganism peeking out of the soil from under a grain of sand? What would you see in your backyard if you were an ant, a mouse, a cat, or a dog? Then again, what would you see if you were a sparrow, first feeding on the ground, then flying into a tree, and then flying to the other end of the neighborhood?

Scale, as we perceive it, is an aspect of diversity in distance and space. Diversity includes every conceivable scale, such as time, viewed from every conceivable place in distance and space simultaneously, from the viewpoint of a soil bacterium, to the viewpoint of an ant, to the viewpoint of a sparrow, and beyond.


Even though protection of soil and its fertility can be justified economically, our human connection with the soil escapes most people. One problem is that traditional, linear economics deals with short-term, tangible commodities, such as agricultural crops, rather than with long-term intangible values, such as the future prosperity of our children. We begin to see that the traditional, linear economic system is not tenable in the face of biological reality when we recognize that land, labor, and capital are finite, and that every ecosystem has a carrying capacity supported by labor and energy.

Decades of poor farming practices in southern Chile left a legacy of eroded soil for all generations.

Those who analyze the soil by means of traditional, linear economic analyses weigh the net worth of protecting the soil only in terms of the expected short-term revenues from future harvests, and they ignore the fact that it's the health of the soil, which produces the yields. In short, they see the protection of the soil as a cost with no benefit because the standard method for computing soil-expectation values commonly assumes that productivity of the soil will either remain constant or increase—but never decline.

Given that reasoning, which is both short-sighted and flawed, it's not surprising that those who attempt to "manage" the land—rather than "take care of it"—seldom see protection of the soil's productivity as cost effective. But if we could predict the real effects of this economic reasoning on long-term yields, we might have a different view of the invisible costs associated with ignoring the health of the soil.

One of the first steps along the road to protecting the fertility of soil is to ask how the various ways humans treat an ecosystem affect its long-term productivity, particularly that of the soil itself. In turn, understanding the long-term effects of human activities requires that we know something about ecosystem stable and productive, such as habitat diversity and health. With such knowledge, we can turn our often "misplaced genius," as soil scientist David Perry rightly calls it, to the task of maintaining the sustainability and resilience of the soil's fertility. Protecting the soil's fertility is buying an ecological insurance policy for our children. " … care of the earth," says farmer and author Wendell Berry, "is our most ancient and most worthy and, after all, our most pleasing responsibility. To cherish what remains of it, and to foster its renewal, is our only legitimate hope."

After all, soil is a bank of elements and water that provides the matrix for the biological processes involved in the cycling of nutrients, which are elements that become nutrients under the right conditions of concentration and availability to plants. In fact, of the sixteen chemical elements required for life, plants obtain all but three—carbon, hydrogen, and oxygen—from the soil. The soil stores these essential elements in undecomposed litter and in living tissues and recycles them from one reservoir to another at rates determined by a complex of biological processes and climatic factors.

As soil scientist W. C. Lowdermilk wrote in 1939, "If the soil is destroyed, then our liberty of choice and action is gone, condemning this and future generations to needless privations and dangers." To rectify society's careless actions, Lowdermilk composed what has been called the "Eleventh Commandment," which demands the full and unified attention of every gardener, farmer, and forester if we are to fulfill our God-given roles as trustees of the soil for the benefit of the present generation and all those of the future:

Thou shalt inherit the Holy Earth as a faithful steward, conserving its resources and productivity from generation to generation. Thou shalt safeguard thy fields from soil erosion, thy living waters from drying up, thy forests from desolation, and protect thy hills from overgrazing by thy herds, that thy descendants may have abundance forever. If any shall fail in this stewardship of the land, thy fruitful fields shall become sterile stony ground and wasting gullies, and thy descendants shall decrease and live in poverty or perish from off the face of the earth.⁸

Here, it is important to keep in mind that however you view it, a pinch of fertile soil—like good quality water— is one of the pillars of sustainable community. Destroy the fertility of your community's soil, and nothing else you do will much matter because the soil is the stage upon which your community's life-play ultimately depends.

Having learned nothing from the agricultural disaster, today's industrial forestry will leave its own legacy of depleated soils in southern Chile for the generations yet to come.


  1. The Holy Bible, Authorized King James Version. World Bible Publishers, Iowa Falls, IA. Numbers 35:34.

  2. The discussion about the importance of soil in this paragraph is based on:  (1) G.C. Daily, P.A. Matson, and P.M. Vitousek. 1997. Ecosystem services supplied by soil. Pp 113-132. In:  G. Daily, editor. Nature's Services:  Societal Dependence on Natural Ecosystems. Island Press, Washington, D.C. and (2) Gretchen C. Daily, Susan Alexander, Paul R. Ehrlich, and others. 1997. Ecosystem Services:  Benefits Supplied to Human Societies by Natural Ecosystems. Issues in Ecology 2:1-16.

  3. L.R. Oldeman, V. van Engelen, and J. Pulles. 1990. The extent of human-induced soil degradation. Annex 5 of L.R. Oldeman, R.T.A. Hakkeling, and W.G. Sombroek, World Map of the Status of Human-Induced Soil Degradation: An Expanatory Note, rev. 2d ed. Wageningen: International Soil Reference and Information Centre.

  4. The discussion of the formation of soil is based on:  (1) Mark Ferns. 1995. Geologic Evolution of the Blue Mountains Region, The Role of Geology in Soil Formation. Natural Resource News 5:2-3,17; (2) James L. Clayton. 1995. Processes of Soil Formation. Natural Resource News 5:4-6; (3) Alan E. Harvey.1995. Soil and the Forest Floor: What It Is, How It Works, and How To Treat It. Natural Resource News 5:6-9; (4) Elaine R. Ingham. 1995. Organisms in the Soil:  The Functions of Bacteria, Fungi, Protozoa, Nematodes, and Arthropods. Natural Resource News 5:10-12, 16-17; (5) Bernard T. Bormann, Deane Wang, F. Herbert Bormann, and others. 1998. Rapid plant-induced weathering in an aggrading experimental ecosystem. Biogeochemistry 43:129-155; (6) Michael Snyder. 2004. Why is Soil Compaction a Problem in Forests? North Woodlands 11:19; and (7) A. G. Jongmans, N. van Breemen, U. Lundström, and others. 1997. Rock-eating fungi. Nature 389:682-683.

  5. Matthias C. Rillig, Sara E. Wright, Michael F. Allen, and Christopher B. Field. 1999. Rise in carbon dioxide changes soil structure. Nature 400:628.

  6. This paragraph is based on:  (1) Albert Tietema, Claus Beier, Pieter H.B. de Visser, and others. 1997. Nitrate leaching in coniferous forest ecosystems:  The European field-scale manipulation experiments NITREX (nitrogen saturation experiments) and EXMAN (experimental manipulation of forest ecosystems). Global Biogeochemical Cycles 11:617-626 and (2) Paul J. Squillace, Michael J. Morgan, Wayne W. Lapham, and others. 1999. Volatile Organic Compounds in Untreated Ambient Groundwater of the United States, 1985-1995. Environmental Science & Technology 33:4176-4187.

  7. The preceding five paragraphs are based on:  Elaine R. Ingham. 1995. Organisms in the Soil:  The Functions of Bacteria, Fungi, Protozoa, Nematodes, and Arthropods. Natural Resource News 5:10-12, 16-17

  8. W.C. Lowdermilk. 1975. Conquest of the Land Through 7,000 Years. Agricultural Information Bulletin No. 99, U.S. Department of Agriculture, Soil Conservation Service, U.S. Government Printing Office, Washington, D.C. 30 pp.




Chris Maser
Corvallis, OR 97330

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