Soil—writer William Bryant Logan has called it “the ecstatic skin of the earth.” How appropriate for a medium so teeming with life. According to Discovery Education, “Each shovel of soil holds more living things than all the human beings ever born.” And those are just the ones we’ve identified so far.

Living on uplifted limestone as I do, I have a deep appreciation for soil. Anywhere that gives a little when I walk, that doesn’t have to be “tilled” with a pry bar, is a good place to put a plant. With luck, and a little rain at the right time, that blend of organic material and minerals we call soil will nurture that plant to maturity. And with even more luck to protect it from insects and bad weather, that plant will bloom or fruit and bring me a great deal of pleasure.

“How can I stand on the ground every day and not feel its power?” Logan writes in Dirt, now the basis for a feature length documentary. “How can I live my life stepping on the stuff and not wonder at it?” How can we? Unfortunately, it’s easy.

Indeed, we can go a lifetime without thinking about the origin of our soil. Is it the product of weathered rocks? The bodies of long-dead sea creatures? Was it born of the movement of glaciers? Or spewed as a hot, viscous liquid from somewhere far below the surface of the earth?

“’Dust thou art, and unto dust shalt thou return.’ All we go down to the dust,” reads The Burial of the Dead, Rite I. They are sobering words, but not frightening to one who knows the soil whereof he or she was made.