World Soil Day:
International Volunteer Day for Economic
and Social Development
December 5, 2018
“How
can I stand on the ground every day and not feel its power? How can I live my life stepping on
this
stuff and not wonder at it?” William
Bryant Logan, Dirt, The Ecstatic Skin of the Earth, 2007.
The most important natural resource
on Earth is perhaps the least noticed, least appreciated, and least studied of
all the natural assets essential to human flourishing. News outlets provide near-daily reports on
air, water, and energy resources, along with frequent stories about forests,
fisheries, oceans, game/wildlife populations, and mineral resources. But when did you last read or hear a story
about soil? Do you even know what soil is? Do you ever think
about it other than soiled laundry? Have
you ever worried that we might “run out” of soil? Perhaps you should. Soils and soil health are ultimately the source
of most of what we eat.
Most
folks tend to think of soil merely as “dirt,”
a sterile substrate made of ground-down, weathered rocks that gets tracked into
the house and constantly needs to be cleaned out. That idea is partly true, because soil
generally consists of about half solid material, most of which is weathered
rock particles (sand, silt, and clay) and the rest of which is organic material
(plants, animals, microorganisms, and their wastes). The other half of
soil consists of pores, which are tube-like openings between soil particles
that hold air and water needed by plant roots and by the billions of mostly
microscopic organisms that live in the soil.
This
interesting mixture of solids and air/water-filled pores is different in
different places all over the Earth.
Some soil is dry, light-colored, and sandy, while other soil is dense,
heavy, and black with carbon. Have you
ever noticed? Some soil is red and
filled with iron oxides, while other soil is blue-black and slippery, formed in
the low-oxygen conditions of wetlands.
Some soil seems to be bursting with nutrients because plants grow
luxuriously there, accompanied by earthworms and lots of diverse insect species,
while other soil appears poisoned or blighted in some way because nothing grows,
no matter how much it is coaxed to produce.
Our
knowledge of soils and the science of how they work developed relatively recently. In 1886, Russian Vasily Dokuchaev was the
first to postulate that five “soil-forming factors” are responsible for
creating or forming a soil. The factors
are: (1) parent material (i.e., geological material such as basalt, granite,
limestone, shale, etc., which contain differing combinations of minerals); (2)
climate; (3) topography; (4) biota (plant, animal, microbial life);
and (5) time. Together, these factors
explain how the massive layers of rock in the Earth’s crust have been slowly, inexorably covered by thin layers of soil that differ in their chemical, physical,
and biological properties, providing for different uses of these resources in
different areas.
For
instance, soils formed under tall-grass prairies, such as those in Iowa, the
Ukraine, Mongolia, and the Pampas area of Argentina, are deep, rich, highly
fertile soils that are very productive agriculturally. These regions have become the breadbaskets of
the world. Soils formed under forests,
such as those in northern Michigan, Maine, and Canada, can be very sandy,
acidic, and low in nutrients. This lowers
agricultural value but is usable as timber lands or dug out as construction
materials. Soils formed in the
low-oxygen conditions of wetlands are highly fertile peat or muck soils that
can be used to grow lush crops (if drained) or dug up and burned as fuel (as in
the United Kingdom). Soils formed under
forests in hot, humid climates such as Brazil, China, and Malaysia contain high
percentages of kaolinite clay minerals, making them exceptionally useful soils
for creating fine pottery.
Importantly,
while soil is created at different rates depending on the interactions of the
five soil-forming factors in specific areas, soil generally forms exceptionally slowly. The U.S. Department of Agriculture’s Natural
Resource Conservation Service estimates that, on average, it takes about 500 years to form one inch of soil. Given this fact, it is worrisome, to say the
least, to learn that we are depleting our soil resources about 18 times faster,
on average, than it is being replenished.
In other words, under current conventional, highly industrialized
agricultural practices, we are losing approximately one inch of soil every 28
years. This vital natural resource is
being depleted far faster than it is being replaced.
Human civilization, of course, is
built on the many services soil provides.
Most obviously, soil provides a medium in which plants grow. Plants (including trees) supply humans with
food, building materials, clothes, and feed for animals. Plants also generate oxygen in the process of
producing their own food from carbon dioxide and water, and we humans benefit
by breathing that oxygen. Soil is filled
with microrganisms and macroorganisms, called “detritivores,” that eat dead
organisms, tissues, and wastes, turning all these formerly living beings into
nutrients that plants can take up for their own growth. This conveniently prevents the planet from
being buried in dead leaves, twigs, and bodies! In addition, soil filters water as it makes
its way down through the soil profile, removing contaminants.
Without
soil, very few of these essential services would be available to us free of
charge. Soil is also used to produce
clay bricks, pottery vessels, cookware, drainage pipes, roofing tiles, and
other useful and beautiful items. In the
past century, we learned that soil can supply us with important medicines such
as penicillin and other antibiotics derived from soil bacteria. Research is actively underway for more
life-saving cures, including possibly for cancer. There is also a vital health benefit of people
being directly exposed to nature’s soil.
Individuals like farmers and gardeners who are routinely exposed to soils
have better immune systems -- our primary defense against most infectious
pathogens.
Increasingly
important in the context of climate change which even the US military and intelligence
agencies consider in the national security assessments, we know that
mycorrhizal fungi and other microrganisms living in soil sequester enormous
quantities of carbon, offsetting anthropogenic carbon emissions if they are allowed
to live and thrive. This climate factor,
combined with food production, discovery of new medicines and other soil
factors bond soil directly to our individual and national security.
History teaches lessons about the
importance of studying soil science, but only if we have the eyes to see and
ears to hear. Around 4000 B.C., the
Mesopotamian cultures of Babylonia, Sumeria, and Akkadia built the first cities
of the Western world in the fertile plains between the Tigris and Euphrates
Rivers, in present-day Iraq. They
cultivated thousands of acres near the rivers, growing wheat and barley and
developing the plow, the potter’s wheel, and other useful farming implements. For a few centuries, their success was
stunning. It was achieved using large-scale diversions of river water into the
fields to irrigate the crops and resulting in massive food production that
fueled rapid societal growth and development.
Their crop management model, however, had a fatal flaw: salt.
The Tigris and Euphrates carry large salt loads, and their water’s
continual application to Mesopotamian fields caused the salt content of the
soils to rise to levels far beyond those any crop plants could tolerate. After decades of trying different techniques
to continue food production in these soils, the Mesopotamians ultimately
abandoned most of their fields by 1000 B.C.
Today, three thousand years later, the lands are still barren.
Unfortunately, the Mesopotamian
story is not unique. Many other cultures
through the ages, including the Romans, the medieval Europeans, and others,
have engaged in imprudent soil management practices that yielded short-term
economic gains and adequate food supplies but, over the longer term, resulted
in declining fertility, ruined soils, and eventually societal collapse. Some folks today, eyeing the lopsided
soil-loss-versus-replenishment rates of our breadbasket soils in Iowa and
elsewhere around the world, are concerned that history may once again be repeating
itself, if nothing is done to address the degradation of precious soil
resources.
Soil
is a miraculous, complex, living thing that needs our persistent attention,
respect, gratitude, and care. A new
international focus on “soil health” will hopefully bring the importance and
value of soil to the fore, driving policy changes in the United States and
worldwide to preserve this critical resource, and all the benefits it supplies,
into the future. Human security and sustainable
civilizations included. More informed political attention is urgently
needed in every nation and international body.
Next time you are walking through your yard,
garden, park, or pasture, honor the life that is hidden below your
feet. It is literally the foundation for our sustenance and very
existence. If enough people volunteer their time to improving the health
of our soils, our environment, and each other -- we can better enhance both our
world's economic and social development and global security for all.
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