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Elevated Atmospheric Carbon Dioxide and Leaf Litter Chemistry: Influences on Microbial Respiration and Net Nitrogen Mineralization
Author(s) -
Randlett Diana L.,
Zak Donald R.,
Pregitzer Kurt S.,
Curtis Peter S.
Publication year - 1996
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1996.03615995006000050041x
Subject(s) - mineralization (soil science) , plant litter , chemistry , cycling , environmental chemistry , soil respiration , nitrogen cycle , carbon dioxide , nitrogen , respiration , carbon cycle , soil water , organic matter , dissolved organic carbon , carbon dioxide in earth's atmosphere , zoology , soil carbon , ecosystem , botany , nutrient , ecology , biology , archaeology , organic chemistry , history
Elevated atmospheric CO 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 2 would slow C and N transformations in soil. Soils were amended with Populus leaf litter produced under two levels of atmo‐spheric CO 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 2 ‐C and inorganic N were fit to a first order rate equation [ y = A (1 − e − kt )] using nonlinear regression analyses. Although CO 2 treatment affected soluble sugar concentration in leaf litter (ambient = 120 g kg −1 , elevated = 130 g kg −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 2 . Net N mineralization was a linear function of time and was not significantly different for leaves grown at ambient (50 mg N kg −1 ) and elevated CO 2 (35 mg N kg −1 ). Consequently, we found no evidence for the hypothesis that leaf litter produced at elevated atmospheric CO 2 will dampen the rates of C and N cycling in soil.