Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: October 27, 1999
Publication Date: N/A
Technical Abstract: Microbial parameters were characterized for a wetland system that is associated with a first-order stream in an agricultural ecosystem. The wetland soil generally consists of a histosol (150 to 200 cm) above an aerobic sand aquifer. The histosol has been buried by a post-settlement deposit(ca. 20 cm)consisting of mineral soil eroded from the agricultural fields. The top layer of the mineral deposit (ca. 5 cm) is enriched with organic matter recently deposited in the wetland through litter fall. Biological parameters such as denitrification potential, respiration, and microbial biomass were measured at various depths within the wetland soil. The highest biological activities and denitrification potentials were found in the uppermost mineral layer containing recently added organic material with at least an order of magnitude less activity in the underlying histosol. Soil denitrification potential closely paralleled respiration and biomass measurements. This work shows that the carbon associated with the buried histosol is largely unavailable for biological activity. It also demonstrates the importance of current carbon deposition on wetland function and indicates the significant impact of surrounding agricultural activity on the biological function of riparian wetland systems.