soil

The living skin of the earth — a mixture of mineral particles, organic matter, water, air, and billions of organisms per handful, formed over centuries by the interaction of rock, climate, biology, and time. Soil is not dirt. Dirt is soil that has been displaced, removed from the system that made it. Soil is a community, stratified into layers called horizons, each with its own character and function. A single teaspoon of healthy soil contains more microorganisms than there are people on the planet.