Soil carbon stocks after conversion of Amazonian tropical forest to grazed pasture: Importance of deep soil layers

Stahl Clément, Freycon Vincent, Fontaine Sébastien, Dezécache Camille, Ponchant Lise, Picon-Cochard Catherine, Klumpp Katja, Soussana Jean-François, Blanfort Vincent. 2016. Soil carbon stocks after conversion of Amazonian tropical forest to grazed pasture: Importance of deep soil layers. Regional Environmental Change, 16 (7) : 2059-2069.

https://doi.org/10.1007/s10113-016-0936-0

Article de revue ; Article de recherche ; Article de revue à facteur d'impact

	Version Online first - Anglais Accès réservé aux personnels Cirad Utilisation soumise à autorisation de l'auteur ou du Cirad. Stahl et al. 2016 Regional Environmental Change.pdf Télécharger (794kB) \| Demander une copie
	Version publiée - Anglais Accès réservé aux personnels Cirad Utilisation soumise à autorisation de l'auteur ou du Cirad. art%3A10.1007%2Fs10113-016-0936-0.pdf Télécharger (938kB) \| Demander une copie

Quartile : Q1, Sujet : ENVIRONMENTAL STUDIES / Quartile : Q2, Sujet : ENVIRONMENTAL SCIENCES

Liste HCERES des revues (en SHS) : oui

Thème(s) HCERES des revues (en SHS) : Géographie-Aménagement-Urbanisme-Architecture

Résumé : 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.

Mots-clés Agrovoc : forêt, forêt tropicale, séquestration du carbone, cycle du carbone, déboisement, pâturages, matière organique du sol, couverture végétale, écosystème forestier, plante d'abroutissement, plante fourragère, utilisation des terres