Soil is the digestive system of the earth. Think about it: organisms in the soil consume, digest, and recycle organic matter—just like your stomach digests the food you eat. Like your gut, the soil is a living organ, teeming with microorganisms that are tasked with exchanging nutrients and keeping plants and ecosystems healthy. And like your diet, improper “food”—what we add to the soil—can make it very sick or very healthy.