You probably see this every day, but most people don't notice it. What is it?
These are earthworm castings. Earthworms basically eat their way through the soil. In the process, they digest and absorb some of the nutrients, but they also break down parts of the soil, making it richer in nitrogen and phosphates. This also mixes the soil, aerate the soil, and makes it easier for rain to penetrate the soil. All in all, they have quite an impact on the soil.