Plant and Soil

, Volume 323, Issue 1–2, pp 309–322

Soil carbon dynamics following afforestation of a tropical savannah with Eucalyptus in Congo

  • Daniel Epron
  • Claire Marsden
  • Armel Thongo M’Bou
  • Laurent Saint-André
  • Rémi d’Annunzio
  • Yann Nouvellon
Regular Article

Abstract

Soil organic matter is a key factor in the global carbon cycle, but the magnitude and the direction of the change in soil carbon after afforestation with Eucalyptus in the tropics is still a matter of controversy. The objective of this work was to understand the dynamics of soil carbon in intensively managed Eucalyptus plantations after the afforestation of a native savannah. The isotopic composition (δ) of soil carbon (C) and soil CO2 efflux (F) were measured on a four-age chronosequence of Eucalyptus and on an adjacent savannah. δF was used to partition F between a C3 component and a C4 component, the latter corresponding to the decomposition of a labile pool of savannah-derived soil carbon (CSL). The mean residence time of CSL was 4.6 years. This further allowed us to partition the savannah-derived soil carbon into a labile and a stable (CSS) carbon pool. CSL accounted for 30% of soil carbon in the top soil of the savannah (0–5 cm), and only 12% when the entire 0–45 cm soil layer was considered. The decrease in CSL with time after plantation was more than compensated by an increase in Eucalyptus-derived carbon, and half of the newly incorporated Eucalyptus-derived carbon in the top soil was associated with the clay and fine silt fractions in the 14-year-old. stand. Increment in soil carbon after afforestation of tropical savannah with Eucalyptus is therefore expected despite a rapid disappearance of the labile savannah-derived carbon because a large fraction of savannah-derived carbon is stable.

Keywords

13Chronosequence Eucalyptus Soil carbon Savannah Tropical plantation 

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  • Daniel Epron
    • 1
    • 2
    • 5
  • Claire Marsden
    • 1
    • 3
    • 4
  • Armel Thongo M’Bou
    • 1
    • 3
  • Laurent Saint-André
    • 4
  • Rémi d’Annunzio
    • 3
    • 4
  • Yann Nouvellon
    • 3
    • 4
  1. 1.Nancy Université, Université Henri Poincaré, Faculté des Sciences, UMR 1137, Ecologie et Ecophysiologie ForestièresVandoeuvre les NancyFrance
  2. 2.INRA, UMR 1137, Ecologie et Ecophysiologie ForestièresCentre de NancyChampenouxFrance
  3. 3.UR2PI, BP 1291Pointe-NoireRepublic of Congo
  4. 4.CIRAD, UPR-80Montpellier cedex 5France
  5. 5.UMR INRA UHP ‘Ecologie et Ecophysiologie Forestières’Université Henri PoincaréVandoeuvre cedexFrance

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