Language is a funny thing, especially English as it is a linguistic conglomerate which makes for lots of potential fun. And for botanists and horticulturalists, nothing is more fun that when someone tries to make sense out of soil versus dirt.
Here I will pass along neither dictionary nor professorial opinion, but the New England yankee wisdom dispensed by my Father, the gardener. If anyone referred to the material in his garden as dirt, he'd reply, "It's soil." "Dirt is something you find under your finger nails and in certain kinds of books and movies." No one ever has been accused of using soily language, so this distinction always made a certain sense to me.
Of course as a biologist I know that soil is a complex substance, part inorganic and part organic. A cubic centimeter of soil, a volume about the size of a sugar cube for those of you somewhat metrically challenged, could harbor some 8-20 million organisms. Even the smell of soil, that earthy odor, comes from the metabolic activities of certain bacteria.
So something might start out as dirt, but if composted correctly, it can become soil. And in this I note that for years I have used two layers of newspaper covered with straw to mulch my kitchen garden. Although the data is not publishable, I'm quite certain that the opinion pages of our local newspaper compost the most quickly and thoroughly.
The Geology of Star Trek: I. Minerals, Crystals and Alien Life Forms
34 minutes ago in History of Geology