Earthworms, the hardworking invertebrates that grace the upper layers of soil, have long been considered helpful in our home gardens. Earthworms are prolific munchers, grinding up organic material and sediment grains that make up soils. Although they are very different animals, worms, like many poultry, have gizzards.
Click here for original story, The earthworm effect: Unraveling soil weathering dynamics
Source: Phys.org