Just dirt? Really?! I’ve always thought you would at least need chemically pure elements in precise amounts. Would any old dirt have enough of whatever elements are needed for, say that T-bone? Could you use the same dirt for everything? I suppose you could recycle garbage into useful &/or edible stuff?
It is close to magic, for me.
Well, "chemically pure" and "precise amounts" take on new meanings when you can manipulate matter at the atomic scale. Each robot selects the atoms it needs one at a time - multiplied by trillions of robots, each running at incedible speeds.
Consider what a cow is made of - the plants that it eats! And the plants? Add some carbon dioxide and nitrogen from the air and yes, dirt.
We are mainly carbon and water, after all. Now there may be some trace elements missing from your shovelful of dirt, so a few miniscule vials and that should be it.