Professor of Earth and Space Sciences at the University of Washington, and author of Dirt: The Erosion of Civilizations, David Montgomery wrote:
substantial progress in soil conservation, the United States Department
of Agriculture estimates that millions of tons of topsoil are eroded
annually from farmers' fields in the Mississippi River basin. Every
second, North America's largest river carries another dump truck's load
of topsoil to the Caribbean. Each year, America's farms shed enough soil
to fill a pickup truck for every family in the country. This is a
phenomenal amount of dirt. But the United States is not the biggest
waster of this critical resource. An estimated twenty-four billion tons
of soil are lost annually around the world — several tons for each
person on the planet. Despite such global losses, soil erodes slowly
enough to go largely unnoticed in anyone's lifetime."
Read why the loss of topsoil is important to each of us: Does Dirt Need Saving?