Milorganite: The Essence of Earth Day

It’s fitting that Wisconsin, the origin of Earth Day, is home to the world’s longest-running and nation’s largest recycling program: Milorganite.

Earth Day, which began in 1970 at the prompting of then Wisconsin U.S. Senator Gaylord Nelson, evokes images of volunteers clearing debris from shorelines, elementary school students planting trees, and communities collecting hazardous materials from homeowners to protect land and water. Earth Day was the birth of the modern environmental movement.

But how does Milorganite—a fertilizer—fit into Earth Day’s focus on environmental stewardship?...