How is the earthworm's digestive system adapted for extracting relatively small amounts of food from large amounts of ingested soil?

In order to extract the small amount of nutrients present in the soil, earthworms must ensure that the soil resides within their bodies for longer periods of time. This is achieved by the earth worm's relatively long intestines. The intestines comprise two-thirds of the earth worm's body, meaning they provide a large surface area as well as a longer time for the absorption of nutrients.