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Títol:
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Factors regulating carbon mineralization in the surface and subsurface soils of Pyrenean mountain grasslands
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Autor/a:
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García-Pausas, Jordi; Casals, Pere; Camarero, Lluís; Huguet, Carme; Thompson, Roy; Sebastià, Ma. T.; Romanyà i Socoró, Joan
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Notes:
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Although a large amount of soil carbon (C) is stored in subsurface soils, most studies on soil C dynamics
focus on the upper layers. The aim of this study is to assess the factors that regulate C mineralization in
mountain grassland soils under standard laboratory conditions to compare regulation mechanisms at
surface and subsurface horizons. For this purpose soil samples of surface and subsurface horizons from
35 locations were incubated under laboratory conditions, CO2 efflux rates were measured and microbial
biomass C (MBC) and net N mineralization were determined. We also analysed the samples for pH,
extractable C after fumigation (Cfe), potentially mineralizable N (PMN), reactive and non-reactive P, sum
of exchangeable bases and clay content in order to assess the influence of soil characteristics on C
mineralization. The influence of climate of each site on soil C mineralization under the same laboratory
conditions was also explored for surface and subsurface horizons. C mineralization in surface horizons
related positively with Cfe content, suggesting that microbial activity in this horizon was mainly regulated
by the availability of C. By contrast, in subsurface horizons, C mineralization related with PMN and
was independent of measured C fractions, suggesting that microbial activity in subsurface horizons was
limited by the availability of N and that the available forms of C were more stable in these horizons. The
effects of local climate on laboratory C mineralization were significant in both soil horizons, with lower
rates of C mineralization being recorded in soils from wetter and warmer sites. This fact, suggested that
the C stabilisation mechanisms in mountain grassland soils may be affected by the climate in which soils
develop.
This study was partially funded by the European Commission (EMERGE and CarboEurope-IP projects), by the Spanish Ministry of Science and Education (CARBOPAS and Agroeco projects) and INIA (Balangeis project). CEAM is financially supported by Generalitat Valenciana and Bancaixa. |
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Matèries:
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-Carbon mineralization
-Climate
-Microbial biomass carbon
-Mountain grasslands |
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Drets:
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(c) Elsevier Ltd., 2008
info:eu-repo/semantics/restrictedAccess |
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Tipus de document:
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article
publishedVersion |
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Publicat per:
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Elsevier
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Compartir:
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