PI-PARMELEE, EDWARDS, STINNER, and GROFFMAN: Recent research indicates that earthworms are significant organisms in affecting key transformations of carbon and nitrogen in agroecosystems. Earthworms can increase the cycling of carbon and nitrogen by interacting with the microbial community and by altering soil structural properties. Deqpite increasing evidence that earthworms have a major role in nutrient cycling processes in agroecosystems, little research has addressed the role of earthworms on ecosystem-level flux of nutrients in the field. Established enclosures will be used where earthworm populations have been either reduced, left un-manipulated, or increased. The research will address the question of what are the ecosystem-level effects of earthworms on the conservation and loss of carbon and nitrogen in agroecosystems. This research is important because it will, for the first time, examine how a specific group of soil invertebrates can control the balance between storage and loss of nutrients in ecosystems. The research will develop a model approach for investigating the effects of key organisms on ecosystem-level flux by combining studies of biological, chemical, and physical processes. The research also is relevant to basic ecosystem questions concerning nutrient cycling processes, and will provide essential data to evaluate sustainability in agroecosystems because of the focus on storage and loss of nutrients.
