Soil Basics

Electron micrograph of a soil fungus

Soil is an amazing substance. A complex mix of minerals, air, water, and countless microorganisms, soils forms at the surface of land and comes in many types. Put another way, soil is the thin, outermost layer of Earth’s crust, and like our own skin, we can’t live without soil.

Why? Soil performs many critical functions in almost any terrestrial ecosystem, whether a farm, forest, prairie, or city.

  • Most of our food comes directly or indirectly from plants anchored in, and nourished by, soil
  • Soils modify the atmosphere by emitting and absorbing dust and gases, including carbon dioxide, methane, and water vapor
  • Soils provide habitat for soil organisms--mostly microscopic creatures that account for most of the life on Earth
  • Much of the water we drink and use every day has been filtered and purified by soil
  • Soils process and recycle nutrients, including carbon, so that living things can use them over and over again
  • Soils serve as the foundation for the construction of roadbeds, dams, and buildings

Like our skin, soil is easy to take for granted—and to damage.


Soil Scientists: Who We Are, What We Do

Phil Small
March 19, 2015

As an art major at the University of California–Davis, consulting soil scientist Phil Small says he always dug clay much more than the...

Amy Densborn in lab with students
March 10, 2015

Amy Densborn, a teacher at Lewis Cass Junior and Senior High School in Walton, IN was selected as the recipient of a $1,500 grant from Soil...

January 09, 2015

This month, we profile retired USDA-ARS plant physiologist and research leader Betty Klepper, who was elected the first female Fellow of the Soil...

group photo with Bill Shuster
December 18, 2014

Bill Shuster is a research hydrologist with the USEPA, based in Cincinnati, OH. He recently overheard his daughter explaining his work to her...

What's Soil Got to Do with... Food?

Screen shot of video about soil and food

... Water?

Screen shot of video about soil and water

... Medicine?

Screen shot of video about soil and medicine