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ARS Home » Midwest Area » St. Paul, Minnesota » Soil and Water Management Research » Research » Publications at this Location » Publication #72710
Title: NATURAL ABUNDANCE ISOTOPE IDENTIFICATION OF CARBON IN EARTHWORM CASTS

Author
item Linden, Dennis
item Clapp, Charles
item TROJAN M D - MN POLLUTION CONTROL AGCY

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/3/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The role of earthworms in the cycling of carbon from plant residues into soil organic matter has been known for eons. Soil organic matter is affected by the physical ingestion and translocation and by the mixing and enhanced microbial respiration which occurs within the earthworm gut. Casts from three common earthworm species Aporrectodea tuberculata, Lumbriscus rubellus, and Lumbriscus terrestris, which range from a small subsurface dweller and feeder to a large surface-feeder and deep-dweller, were collected periodically and frozen immediately for later analysis of total and isotope carbon. Individuals of each species were incubated in three soils ranging in carbon content between 1.5 to 3.0 percent. The earthworms were fed either corn or soybean residues for several weeks. Results indicate that fecal deposition carbon content can be doubled and the increase is related to the relative consumption of soil and residues and that the increased carbon in the worm casts is entirely due to fresh residue.