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Étude structurale et dynamique des fractions lipidiques et organiques réfractaires de sols d'une chronoséquence forêt/maÏs (Cestas, sud-ouest de la France)

Katell Quénéa
Abstract : Soil organic matter (OM) is an important pool of carbon on Earth. The OM stock depends on biologic factors, thus soil OM constitutes the global carbon cycle compartment the more sensitive to anthropic and climatic disturbances. In the course of biodegradation, OM represents an atmospheric CO2 source, hence a better knowledge of its structure and dynamic modelling is necessary and to forecast atmospheric CO2 variation, linked to environmental modifications. Different kinetic pools have been distinguished in soil OM which residence times vary from years to millennia. The more important residence time pools represent a stable stock of carbon poorly submitted to disturbance. The qualitative determination and quantitative estimation of this stock of carbon still has to be improved. During this work, we have studied the structure and dynamic of lipids, often considered as relatively stable, and of a chemically refractory fraction, obtained by a protocol including acid and basic hydrolyses. This fraction can present a resistance to biodegradation. Thus, we have studied two sandy soils (podzols) belonging to a chronosequence: a forest soil converted to maize cropping. Lipid composition determination in three particle-size fractions (sand, silt and clay) of these two soils, especially by GC-MS, makes possible to have access to substantial information on their source and dynamic. Spectroscopic methods (13C NMR, FTIR) combine to pyrolytic methods and chemical oxidations provide information on refractory organic matter (ROM) chemical composition and structure. Soil comparison has revealed the corn cropping influence on lipids and ROM. Moreover natural 13C abundance makes possible to obtain data on OM, lipids and ROM dynamic.
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https://pastel.archives-ouvertes.fr/pastel-00001071
Contributor : Ecole Chimie Paristech <>
Submitted on : Tuesday, February 22, 2005 - 8:00:00 AM
Last modification on : Tuesday, February 22, 2005 - 8:00:00 AM
Long-term archiving on: : Thursday, September 30, 2010 - 6:23:29 PM

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Katell Quénéa. Étude structurale et dynamique des fractions lipidiques et organiques réfractaires de sols d'une chronoséquence forêt/maÏs (Cestas, sud-ouest de la France). Chemical Sciences. Chimie ParisTech, 2004. English. ⟨pastel-00001071⟩

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