"When the Europeans first arrived in North America, the average depth of the topsoil was 53.34 cm (1Â¾ ft) and it was rich in the types of symbiotic organisms necessary for plant roots to absorb minerals from the soil. Today North America averages around 15.24 cm (6 in) of topsoil and most if it is exhausted of nutrients and much is devoid of life."

Source : "Threshold: The Progressive Plan to Pull America Back from the Brink". Book by Thom Hartmann, p.22, July 23, 2009.

Thom Hartmann

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