Elevated atmospheric carbon dioxide and leaf litter chemistry: Influences on microbial respiration and net nitrogen mineralization
- Univ. of Michigan, Ann Arbor, MI (United States)
- Michigan Technical Univ., Houghton, MI (United States)
- Ohio State Univ., Columbus, OH (United States)
Elevated atmospheric CO{sub 2} has the potential to influence rates of C and N cycling in terrestrial ecosystems by altering plant litter chemistry and slowing rates of organic matter decomposition. We tested the hypothesis that the chemistry of leaf litter produced at elevated CO{sub 2} would slow C and N transformations in soil. Soils were amended with Populus leaf produced under two levels of atmospheric CO{sub 2} (ambient and twice-ambient) and soil N availability (low and high). Kinetic parameters for microbial respiration and net N mineralization were determined on soil with and without litter during a 32-wk lab incubation. Product accumulation curves for CO{sub 2}-C and inorganic N were fit to a first order rate equation [y=A(1-e{sup -kt})] using nonlinear regression analyses. Although CO{sub 2} treatment affected soluble sugar concentration in leaf litter (ambient =120 g kg{sup -1}, elevated =130 g kg{sup -1}), it did not affect starch concentration or C/N ratio. Microbial respiration, microbial biomass, and leaf litter C/N ratio were affected by soil N availability but not by atmospheric CO{sub 2}. Net N mineralization was a linear function of time and was not significantly different for leaves grown at ambient (50 mg N kg{sup -1}) and elevated CO{sub 2} (35 mg N kg{sup -1}). Consequently, we found no evidence for the hypothesis that leaf litter produced at elevated atmospheric CO{sub 2} will dampen the rates of C and N cycling in soil. 35 refs., 1 fig., 4 tabs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 420856
- Journal Information:
- Soil Science Society of America Journal, Vol. 60, Issue 5; Other Information: PBD: Sep-Oct 1996
- Country of Publication:
- United States
- Language:
- English
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