%0 Journal Article
%T Continuous soil carbon storage of old permanent pastures in Amazonia
%A Stahl, C.
%A Fontaine, S.
%A Klumpp, K.
%A Picon-Cochard, C.
%A Grise, M.M.
%A Dezecache, C.
%A Ponchant, L.
%A Freycon, V.
%A Blanc, L.
%A Bonal, D.
%A Burban, B.
%A Soussana, J.-F.
%A Blanfort, V.
%J Global Change Biology
%D 2017
%V 23
%N 8
%@ 1365-2486
%F Stahl_etal2017
%O exported from refbase (http://php.ecofog.gf/refbase/show.php?record=783), last updated on Mon, 29 Jan 2018 09:15:44 -0300
%X Amazonian forests continuously accumulate carbon (C) in biomass and in soil, representing a carbon sink of 0.42–0.65 GtC yr−1. In recent decades, more than 15% of Amazonian forests have been converted into pastures, resulting in net C emissions (~200 tC ha−1) due to biomass burning and litter mineralization in the first years after deforestation. However, little is known about the capacity of tropical pastures to restore a C sink. Our study shows in French Amazonia that the C storage observed in native forest can be partly restored in old (≥24 year) tropical pastures managed with a low stocking rate (±1 LSU ha−1) and without the use of fire since their establishment. A unique combination of a large chronosequence study and eddy covariance measurements showed that pastures stored between −1.27 ± 0.37 and −5.31 ± 2.08 tC ha−1 yr−1 while the nearby native forest stored −3.31 ± 0.44 tC ha−1 yr−1. This carbon is mainly sequestered in the humus of deep soil layers (20–100 cm), whereas no C storage was observed in the 0- to 20-cm layer. C storage in C4 tropical pasture is associated with the installation and development of C3 species, which increase either the input of N to the ecosystem or the C:N ratio of soil organic matter. Efforts to curb deforestation remain an obvious priority to preserve forest C stocks and biodiversity. However, our results show that if sustainable management is applied in tropical pastures coming from deforestation (avoiding fires and overgrazing, using a grazing rotation plan and a mixture of C3 and C4 species), they can ensure a continuous C storage, thereby adding to the current C sink of Amazonian forests.
%K carbon storage
%K CN coupling
%K deep soil
%K mixed-grass pasture
%K native forest
%U http://dx.doi.org/10.1111/gcb.13573
%P 3382-3392