Response of forest seedling/soil microcosms to elevated CO{sub 2} and soil temperature, water, and light: Carbon and nitrogen mineralization and allocation
- Oregon State Univ., Corvallis, OR (United States)
Soils from 500-year-old old-growth Douglas-fir forests in the western Oregon Cascade Mtns. (945m and 1325m sites) were {open_quotes}incubated{close_quotes} for 32 weeks in controlled-environment chambers. Objectives were (1) to determine the interacting effects of soil temperature and atmospheric CO{sub 2} on N availability in soils, growth of Douglas-fir seedlings, and resulting C & N fluxes among trees, soils, and the atmosphere, and (2) to model these interactions with a version of Fregro linked with the GEM soil-decomposition model. The experiment was a split-plot with a factorial treatment combination containing two leves each of atmospheric CO{sub 2} (350/700 ppm), soil temperature (13.8/17.7{degrees}C), soil C & N (1325m soils had 2.3x more C and 1.25x more N than 945m soils), and vegetation (+/-seedlings). Each wholeplot (chamber) treatment (CO{sub 2} x temperature) was replicated three times. Photosynthetic photon flux density, soil temperature, and volume of added water were determined for each pot and analyzed as covariates. Responses measured include differences in soil C & N mineralization and total soil C & N in the presence/absence of seedlings, the extent to which subsequent seedling growth offsets potential {open_quote}system{close_quote} losses of C & N, and allocation of C & N to foliage and fine roots. Previously reported early results (ESA, 1994) suggest that (1) as hypothesized, soil temperatures is the main driver of changes in both N mineralization and biomass production in seedling microcosms, (2) allocation is primarily influenced by atmospheric CO{sub 2} concentration, and (3) a soil type x soil temperature x CO{sub 2} interaction influences seedling growth.
- OSTI ID:
- 107100
- Report Number(s):
- CONF-9507129-; ISSN 0012-9623; TRN: 95:006512-0016
- Journal Information:
- Bulletin of the Ecological Society of America, Vol. 76, Issue 3; Conference: 80. anniversary of the transdisciplinary nature of ecology, Snowbird, UT (United States), 30 Jul - 3 Aug 1995; Other Information: PBD: Sep 1995
- Country of Publication:
- United States
- Language:
- English
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