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| Titel |
Changes in soil carbon stocks in Brazil due to land use: paired site comparisons and a regional pasture soil survey |
| VerfasserIn |
E. D. Assad, H. S. Pinto, S. C. Martins, J. D. Groppo, P. R. Salgado, B. Evangelista, E. Vasconcellos, E. E. Sano, E. Pavão, R. Luna, P. B. Camargo, L. A. Martinelli |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 10 ; Nr. 10, no. 10 (2013-10-01), S.6141-6160 |
| Datensatznummer |
250085342
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| Publikation (Nr.) |
 copernicus.org/bg-10-6141-2013.pdf |
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| Zusammenfassung |
| In this paper we calculated soil carbon stocks in Brazil studying 17 paired
sites where soil stocks were determined in native vegetation, pastures and
crop-livestock systems (CPS), and in other regional samplings encompassing
more than 100 pasture soils, from 6.58 to 31.53° S,
involving three major Brazilian biomes: Cerrado, Atlantic Forest, and the
Pampa. The average native vegetation soil carbon stocks at 10, 30 and 60 cm
soil depth were equal to approximately 29, 64, and 92 Mg ha−1,
respectively. In the paired sites, carbon losses of 7.5 Mg ha−1 and
11.6 Mg ha−1 in CPS systems were observed at 10 cm and 30 cm soil
depths, respectively. In pasture soils, carbon losses were similar and equal
to 7.5 Mg ha−1 and 11.0 Mg ha−1 at 10 cm and 30 cm soil depths,
respectively. Differences at 60 cm soil depth were not significantly
different between land uses. The average soil δ13C under native
vegetation at 10 and 30 cm depth were equal to
−25.4‰ and −24.0‰, increasing to
−19.6‰ and −17.7‰ in CPS, and to
−18.9‰, and −18.3‰ in pasture
soils, respectively; indicating an increasing contribution of C4 carbon
in these agrosystems. In the regional survey of pasture soils, the soil
carbon stock at 30 cm was equal to approximately 51 Mg ha−1, with an
average δ13C value of −19.67‰. Key
controllers of soil carbon stock in pasture sites were sand content and mean
annual temperature. Collectively, both could explain approximately half of
the variance of soil carbon stocks. When pasture soil carbon stocks were
compared with the average soil carbon stocks of native vegetation estimated
for Brazilian biomes and soil types by Bernoux et al. (2002) there was a
carbon gain of 6.7 Mg ha−1, which is equivalent to a carbon gain of
15% compared to the carbon soil stock of the native vegetation. The
findings of this study are consistent with differences found between
regional comparisons like our pasture sites and plot-level paired study
sites in estimating soil carbon stocks changes due to land use changes. |
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