Wednesday, December 5, 2018

Dec 5 World Soil Day and...


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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