Dig it, of course.
I apologize for grossing out many readers in advance, but a soil scientist at Oregon State University once informed a group of us "All soil is feces." The question is how many guts that feces has been through. Most soil is built-up from soil-building microscopic animals. And you guessed it, much is recycled. Those insects, arthropods, etc. eat feces, organic waste, and humus to create soil. And before you get all disturbed, according to Gifford Pinchot, all plant life on earth requires soil for survival (along with air, water, light, and most recently mycorrhizal fungi). As animals, every one of us is also dependent on soil for survival as well.
Anyone hunting on soil is supported by 20-30 million tiny legs every step they take. It has been estimated every cubic foot of soil contains over 1 million organisms. Most of these are impossible to see without a microscope. The largest soil-building organism locally is a centipede. It is extremely poisonous. The active ingredient is potassium cyanide. A bird which picks up the centipede is unlikely to pick up another one. And it may not survive the first encounter. Cup it in your hand for a short 5 seconds, and you can smell the odor of bitter almonds given off, even on a very cold day without touching it.