Soil vs. dirt

The radio program Living on Earth has been running excerpts from "Home Ground: Language for an American Landscape," a book by renowned nature writer Barry Lopez ("Crossing Open Ground," "Arctic Dreams," "Of Wolves and Men") that defines landscape terms such as pack ice, blind creek, and cascade. On a recent program, they featured a definition that Ethicurean readers might enjoy:

Soil. Erosion, volcanic eruption, earthquakes, floods, tectonic grinding, landslides, and other natural forces act continuously on the earth’s crustal rock, creating various types of debris—gravel deposits, mudflats and the tidal estuaries of creeks, cobble terraces, and beaches of black lava sand. When chemical agents, such as phosphorus and nitrogen, infuse this debris, and biological entities including microbes and earthworms work material into it organic enough to support plants, it becomes soil. A soil that is chemically or organically exhausted, that’s been pulverized or become deeply parched, that has been invaded by decomposing rock, or that’s been fouled by sewage or industrial pollution to the point where it no longer can support plant life, is called dirt.

To hear Lopez himself reading the definition, download an MP3 or stream the audio from Living on Earth.

More information about the book can be found at the Home Ground Project’s webpage.

5 Responsesto “Soil vs. dirt”

  1. Amber says:

    I will never forget my introductory soil science course when the professor said soil is what plants grow in and dirt is what you wash off your face.

  2. Kim says:

    Ha! I was just going to post that my soils prof used to say, “Dirt is just misplaced soil.”

  3. Ooh, since it looks like we have people here with soil knowledge, I have a question. I have noticed that the onions I have been forced to get this winter from the grocery store until my CSA begins again in May have been remarkably strong, both in terms of their flavor and the way they sting my eyes. Yet, the onions I get from my CSA almost never bother me when I’m slicing them up for this or that dish.

    Is this because there is just more growth pressure on these onions – that is, too many of them growing in dirt on big megafarms, not soil on small family farms like my CSA?

  4. Kim says:

    Well, I studied more soil physics and less anything-to-do-with-living-things. But I have to wonder if it isn’t the breed of onion that’s making the difference?

  5. Robert says:

    It is definitely the variety of onion, but could partially be due to the soil content, though not necessarily that they are “growing in dirt on big megafarms”.  The part of the onion that stings your eyes is a natural compound that is exuded when you pierce the cell walls.  It is for all intents and purposes a sulfur compound that, when it hits the moisture in your eyes, turns to sulfuric acid.  At least that is the simple explanation.