Evaluation of 11 terrestrial carbon-nitrogen cycle models against observations from two temperate Free-Air CO2 Enrichment studies.
Bottom Line: Nonetheless, many models showed qualitative agreement with observed component processes.The results suggest that improved representation of above-ground-below-ground interactions and better constraints on plant stoichiometry are important for a predictive understanding of eCO2 effects.Improved accuracy of soil organic matter inventories is pivotal to reduce uncertainty in the observed C-N budgets.
Affiliation: Biogeochemical Integration Department, Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, D-07745, Jena, Germany.Show MeSH
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Mentions: With eCO2, observed NUE at Duke Forest increased by 5 ± 2%, mainly because of a shift of allocation towards lower C : N tissue (wood), whereas the 4 ± 3% decline in foliar N had little effect on NUE (Fig.7). Despite the initially observed increase in NUE at ORNL FACE, NUE did not change over the course of the experiment (+2 ± 5%), as the effects of increased tissue C : N were compensated by increased allocation towards N-rich roots.
Affiliation: Biogeochemical Integration Department, Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, D-07745, Jena, Germany.