Title
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Soil carbon stocks after conversion of Amazonian tropical forest to grazed pasture : importance of deep soil layers
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Author
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Abstract
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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. |
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Language
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English
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Source (journal)
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Regional environmental change. - Heidelberg, 1999, currens
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Publication
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Heidelberg
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2016
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ISSN
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1436-3798
[print]
1436-378X
[online]
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DOI
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10.1007/S10113-016-0936-0
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Volume/pages
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16
:7
(2016)
, p. 2059-2069
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ISI
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000383772100018
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Full text (Publisher's DOI)
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Full text (publisher's version - intranet only)
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