Increased Abundance of Earthworms Under Nitrogen-Fixing Plants Compared to Non-Nitrogen Fixing Plant
Updated: Aug 30, 2019
By: Natalia Furr, Nayla Swanson, Sydney Memminger, Carrie DeJaco
Plant communities affect soil chemistry, which in turn affects organisms within the soil. Soil-inhabiting organisms such as earthworms, which play a very important role in decomposition and nutrient cycling, may be encouraged or inhibited in their contributions to the ecosystem by the types of plants growing in the soil. This study, conducted in North Carolina, investigated the abundance of earthworms in the soil under plants that fix nitrogen and under those that don’t. It was hypothesized that more earthworms would be in the soil under nitrogen-fixing plants than would be under non-nitrogen-fixing plants because the earthworms would be attracted to the more nutrient-rich plant matter of the nitrogen-fixers. We assessed earthworm abundances and length in the soil underneath 3 plants, each of 3 nitrogen-fixing species and 3 non-nitrogen-fixing species. Under the nitrogen-fixing plants, there were significantly greater numbers of earthworms and the worms were longer than those found in the soil under the non-nitrogen-fixing plants. Our results suggest that more rapid nutrient cycling may occur under the nitrogen-fixing plants than under the non-nitrogen fixing plants.