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The Earth Beneath Our Feet

The views expressed are those of the author and are not necessarily those of Scientific American.


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Healthy soil begets healthy plants, says the Dirt Doctor. (photo courtesy of shutterstock)

Some people take Earth Day more literally than others. Howard Garrett is one of them. Better known as the Dirt Doctor, Garrett believes that the health of the planet begins with the earth beneath our feet; it starts with cultivating strong vibrant soil, and blossoms outwards from there.

“Without healthy soil, we won’t have healthy plants, animals or people,” says Garret over the phone from his home in Dallas, Texas, where he advocates for natural organic gardening, landscaping and living.

The soil, he says, is a living entity that’s frequently mistreated. To thrive, it needs to be biologically active and chemically and physically balanced. This means it needs the right ratio of nitrogen, potassium, phosphorous and trace elements like calcium and magnesium. It also needs microorganisms, insects and other animals, as well as good tillage and drainage. This equation ensures a bevy of benefits, including improved plant growth, innate disease and pest resistance, better water filtration, and decreased erosion.

Intensive cultivation, chemical applications and limited crop rotations harm this balance. In turn, the soil suffers and so does its counterparts – water, food, biodiversity and climate.

Ohio State University soil scientist Rattan Lal has a principle that sums up this cycle of deterioration, it’s the law marginality. It states that marginal soils, which are cultivated with marginal inputs, produce marginal yields and support marginal standards of living. Taking it one step further, Lal also says that the process of restoring these marginal soils will not only improve food security, biodiversity and water quality, it can help mitigate climate change.

In an era of soaring concentrations of atmospheric carbon, soil can be an incredible source of atmospheric carbon and a powerful sponge for absorbing it. One example is in Lal’s home state of Ohio (and the greater Midwest corn belt region), which has lost 50 percent of its soil carbon over the last 150 years due to cultivation. This means that most soil in the region has lost about 15 tons of soil per acre over that period.

On the global scale, the soils of the world have been stripped of approximately 100 billion tons of carbon, or 75 to 80 percent of its carbon pool, since the first days of agricultural production. If this soil could be returned to a relatively healthy state, Lal believes it would be similar to drawing down 25 ppm of carbon dioxide (CO2) from the atmosphere. The current level of CO2 in the atmosphere is 394 ppm.

Research from the Rodale Institute, an organization that promotes organic agriculture, says that organic farming can sequester more than 1,000 pounds of carbon per acre of soil. Non-organic soil management can have the opposite effect – a carbon deficit.

Simply, soil health can have far reaching beneficial effects on the environment. Regenerative agriculture embraces this notion. It aspires to strengthen soil productivity through traditional organic practices such as composting, cover cropping, and reducing or eliminating tillage. And the idea is catching on, albeit slowly, says the Dirt Doctor.

“We’re fighting an uphill battle to have healthy soil,” says Garrett, who when asked about the significance of Earth Day as it relates to soil health get a bit cynical before finding the silver lining. “We’re dealing with it every day. It ought to be a 365-day deal.”

Robynne Boyd About the Author: Robynne Boyd began writing about people and the planet when living barefoot and by campfire on the North Shore of Kauai, Hawaii. Over a decade later and now fully dependent on electricity, she continues this work as an editor for IISD Reporting Services. When not in search of misplaced commas and terser prose, Robynne writes about environment and energy. She lives in Atlanta, Georgia.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. jtdwyer 7:40 am 04/23/2012

    Isn’t it very difficult to maintain healthy soil without sufficient water? How does soil respond to drought?

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  2. 2. jgrosay 7:14 pm 04/23/2012

    Ancient french people feared the sky falling down on their heads, others threaten you of eating the earth beneath your feet, come it from it comes, we are in an unstable position, and those who don’t realize it will fare poorly. (Ramon Tamames said the last sentence)

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  3. 3. CharlieinNeedham 12:33 am 04/24/2012

    Where did the earth come from?

    Very few realize that the earth is a remnant of an exploded supernova.

    We know that because complex atoms(that is those other than hydrogen and helium) are only created by fusion inside stars. And most of earth is composed of complex elements

    Thus the earth got here in pieces, from a star that exploded long, long ago, and far, far away. http://topdocumentaryfilms.com/nova-origins/

    The earth, and all the rocky/solid planets (Mercury, Venus, Mars) assembled from the accretion of many smaller objects under the effect of gravity for objects in their own orbit, and from collisions with objects in more elliptical orbits.

    Now that exploding supernova may likely also have been the source of the hydrogen and helium that coalesced at the center of the solar system to create our sun.

    Without the mass of the sun at the center of the solar system to provide the gravity to keep all those solid elements in orbit, the earth never could have formed.

    And if the mass of the sun had not been so great to initiate fusion, the sun would not have been able to generate heat, and the earth would have only been a cold, lifeless planet.

    But where did the water on earth come from?

    Believe it or not, most scientists think it came from comets that are high in water content colliding with early earth!

    And where did the oxygen in our atmosphere come from?

    Believe it or not, the first atmosphere was very toxic, and contained virtually no oxygen.

    It was early life in the form of cyanobacteria that released oxygen as a byproduct of photosynthesis, led to the large amount of oxygen into the atmosphere! http://www.scientificamerican.com/article.cfm?id=origin-of-oxygen-in-atmosphere

    (And obviously animals and us humans could not have existed without oxygen.)

    So I am very happy the good old earth is plenty lucky.

    It was lucky to be formed from the remnants of an exploded star.

    It was lucky the sun ignited to give it heat and light.

    It was lucky comets brought it water for the oceans.

    It was lucky life in the form of cyanobacteria evolved to give earth oxygen in the atmosphere.

    Happy Earth day planet Earth!

    And here’s a toast that your lucky streak continues!

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