Oecologia

, Volume 177, Issue 3, pp 811–821

Increase in soil stable carbon isotope ratio relates to loss of organic carbon: results from five long-term bare fallow experiments

  • Lorenzo Menichetti
  • Sabine Houot
  • Folkert van Oort
  • Thomas Kätterer
  • Bent T. Christensen
  • Claire Chenu
  • Pierre Barré
  • Nadezda A. Vasilyeva
  • Alf Ekblad
Ecosystem ecology - Original research

DOI: 10.1007/s00442-014-3114-4

Cite this article as:
Menichetti, L., Houot, S., van Oort, F. et al. Oecologia (2015) 177: 811. doi:10.1007/s00442-014-3114-4

Abstract

Changes in the 12C/13C ratio (expressed as δ13C) of soil organic C (SOC) has been observed over long time scales and with depth in soil profiles. The changes are ascribed to the different reaction kinetics of 12C and 13C isotopes and the different isotopic composition of various SOC pool components. However, experimental verification of the subtle isotopic shifts associated with SOC turnover under field conditions is scarce. We determined δ13C and SOC in soil sampled during 1929–2009 in the Ap-horizon of five European long-term bare fallow experiments kept without C inputs for 27–80 years and covering a latitudinal range of 11°. The bare fallow soils lost 33–65 % of their initial SOC content and showed a mean annual δ13C increase of 0.008–0.024 ‰. The 13C enrichment could be related empirically to SOC losses by a Rayleigh distillation equation. A more complex mechanistic relationship was also examined. The overall estimate of the fractionation coefficient (ε) was −1.2 ± 0.3  ‰. This coefficient represents an important input to studies of long-term SOC dynamics in agricultural soils that are based on variations in 13C natural abundance. The variance of ε may be ascribed to site characteristics not disclosed in our study, but the very similar kinetics measured across our five experimental sites suggest that overall site-specific factors (including climate) had a marginal influence and that it may be possible to isolate a general mechanism causing the enrichment, although pre-fallow land use may have some impact on isotope abundance and fractionation.

Keywords

Stable carbon isotope ratio Isotope fractionation Rayleigh distillation Natural abundance Soil organic carbon 

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Lorenzo Menichetti
    • 1
  • Sabine Houot
    • 2
  • Folkert van Oort
    • 3
  • Thomas Kätterer
    • 4
  • Bent T. Christensen
    • 5
  • Claire Chenu
    • 6
  • Pierre Barré
    • 7
  • Nadezda A. Vasilyeva
    • 6
    • 8
  • Alf Ekblad
    • 9
  1. 1.Department of Soil and EnvironmentSwedish University of Agricultural SciencesUppsalaSweden
  2. 2.INRA, UMR Environnement et Grandes CulturesThiverval-GrignonFrance
  3. 3.INRA, Unité PessacVersaillesFrance
  4. 4.Department of EcologySwedish University of Agricultural SciencesUppsalaSweden
  5. 5.Department of AgroecologyAarhus University, AU-FoulumTjeleDenmark
  6. 6.AgroParisTech, UMR 7618 BIOEMCO, Bâtiment EGERThiverval-GrignonFrance
  7. 7.Laboratoire de Geologie, UMR8538, Ecole Normale SupérieureParisFrance
  8. 8.North-Eastern Federal UniversityYakutskRussia
  9. 9.School of Science and TechnologyÖrebro UniversityÖrebroSweden

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