“Dirt”-y movie tells how we’ve sold our soils

The last page of every issue of Edible San Francisco contains this anonymous quotation: “Despite its artistic pretensions and its many accomplishments, humankind owes its existence to a six-inch layer of topsoil and the fact that it rains.” One could even go so far and say that most life — plants, birds, reptiles, insects, and mammals — also owes its existence to this thin layer of topsoil. Unfortunately, humanity has been taking topsoil for granted, and paying the price in many ways, from re