Gross Nitrogen transformation rates and Microbial Population Dynamics Under Field and Laboratory Conditions from Two Different Ecosystems: 15N Study. (S03-silva432868-oral)
Authors:
G. Silva* - EPA, Ada, OK
Abstract:
Change of soil and environmental conditions can influence microbial activities and subsequent soil nitrogen (N) transformation processes. The objective of this study was to compare gross N
transformation rates from two ecosystems using disturbed and undisturbed soils. Soil samples (Vertic Argiustolls, USDA) were analyzed at 2, 4, 6, 8 and 12 weeks to determine gross N transformation rates and microbial community changes in the laboratory using disturbed soil lysimeters and in the field using undisturbed soil cores. The average gross N mineralization rate was significantly greater (p -1 d-1 respectively) and in old-field soil (1.0 and 1.1 mg kg-1 d-1 respectively). The similar gross mineralization rates from the two different techniques used in this study could be due to the overwhelming impact of other factors besides soil mixing. In contrast, gross nitrification rates did not differ between ecosystems in either techniques, but were significantly (p 4+ for microbes under field conditions due to root NH4+ uptake. Total aerobic microbial and actinomycete populations were significantly greater in forest soil, but both populations were significantly (p
Speaker Information: Gunadasa Silva, EPA, Ada, OK, Robert S. Kerr Research CenterP.O. Box 1198, Ada, OK 74820; Phone: 580 436 8562; E-mail: [email protected]
Session Information: Tuesday, November 4, 2003, 7:55 AM-11:00 AM Presentation Start: 7:55 AM
Keywords: gross mineralization; nitrification; microbs; 15N
