Soil carbon stocks after conversion of Amazonian tropical forest to grazed pasture : importance of deep soil layers
Stahl, Clément (University of Antwerp. Department of Biology)
Freycon, Vincent (CIRAD (Organization))
Fontaine, Sébastien (Institut national de la recherche agronomique (França). Unité de Recherche sur l'Ecosystème Prairial)
Dezécache, Camille (CIRAD (Organization))
Ponchant, Lise (CIRAD (Organization))
Picon-Cochard, Catherine (Institut national de la recherche agronomique (França). Unité de Recherche sur l'Ecosystème Prairial)
Klumpp, Katja (Institut national de la recherche agronomique (França). Unité de Recherche sur l'Ecosystème Prairial)
Soussana, Jean-Françoise (Institut national de la recherche agronomique (França). Unité de Recherche sur l'Ecosystème Prairial)
Blanfort, Vincent (CIRAD (Organization))

Date:	2016
Abstract:	Recent studies suggest that carbon (C) is stored in the topsoil of pastures established after deforestation. However, little is known about the long-term capacity of tropical pastures to sequester C in different soil layers after deforestation. Deep soil layers are generally not taken into consideration or are underestimated when C storage is calculated. Here we show that in French Guiana, the C stored in the deep soil layers contributes significantly to C stocks down to a depth of 100 cm and that C is sequestered in recalcitrant soil organic matter in the soil below a depth of 20 cm. The contribution of the 50-100 cm soil layer increased from 22 to 31 % with the age of the pasture. We show that long-term C sequestration in C4 tropical pastures is linked to the development of C3 species (legumes and shrubs), which increase both inputs of N into the ecosystem and the C:N ratio of soil organic matter. The deep soil under old pastures contained more C3 carbon than the native forest. If C sequestration in the deep soil is taken into account, our results suggest that the soil C stock in pastures in Amazonia would be higher with sustainable pasture management, in particular by promoting the development of legumes already in place and by introducing new species.
Grants:	European Commission 266018 European Commission 610028
Note:	Altres ajuts: these projects are co-funded by European regional development fund (ERDF / FEDER, 2007-2013).
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	C3 contribution ; Deep soil C ; Native forest ; Old pasture ; Mixed-grass pasture
Published in:	Regional environmental change, Vo. 16, Issue 7, (October 2016) , p. 2059-2069, ISSN 1436-378X

DOI: 10.1007/s10113-016-0936-0

Post-print 31 p, 2.5 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > CREAF (Centre de Recerca Ecològica i d'Aplicacions Forestals) > Imbalance-P
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