Title: Effect of soil compaction and organic matter removal on two earthworm populations and some soil properties in a hardwood forest

Author: Jordan, D.; Hubbard, V. C.; Ponder, F., Jr.; Berry, E. C.

Year: 1999

Publication: Pedobiologia 43(1999): 802-807

Abstract: Earthworms can alter the physical, chemical, and biological properties of a forest ecosystem. Any physical manipulation to the soil ecosystem may, in turn, affect the activities and ecology of earthworms. The effects of organic matter removal (logs and forest floor) and soil compaction on earthworm activities were measured in a central hardwood region (oakhickory) forest in the Missouri Ozarks. Soils in this region are characterized by a cherty residuum that is primarily of the Clarksville series (Loamy-skeletal, mixed, mesic Typic Paledults). Earthworms were collected from a 15 cm depth each spring and fall for 2 years by the handsorting method and estimated on a per meter square basis. Two earthworm species, Diplocardia ornata and Diplocardia smithii, were the most dominant native species found in the site. Organic matter removal decreased the average individual biomass of both species. However, these species responded differently to soil compaction. Soil compaction affected D. ornata adversely and D. smithii favorably. This suggests that the degree of soil compaction was not restrictive to D. smithii (2-mm dia) but it was to D. ornata (5 mm dia). Moreover, the apparent better soil environmental conditions resulting from the remaining organic matter in compacted soil enhanced D. smithii population and growth. Sampling position affected D. ornata but not D. smithii. Other factors influencing the ecology and activity of these two species will require further study.