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The Earth Beneath Our Feet

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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."

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

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