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| Titel |
Spatial heterogeneity of soil organic carbon in a small alpine catchment (Grindelwald, Switzerland) |
| VerfasserIn |
U. Poppe, N. Kuhn |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250025870
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| Zusammenfassung |
| Soils represent a major pool in the global carbon cycle. Their behaviour as a carbon reservoir
in global climate and environmental issues is far from fully understood. Surface soil organic
carbon (SOC) pools and turnover times are particularly sensitive to a range of factors, such as
climate, vegetation, topography, soil properties, soil and crop management and other
anthropogenic conditions. These factors are important to formulate process-based C cycling
models and to evaluate the influence of future land use and climate changes on SOC content.
Mountain environments are strongly affected by and highly sensitive to climate change
(geomorphology, vegetation), while also experiencing significant land use change. Little
attention has so far been given to the spatial heterogeneity of alpine SOC stocks.
In mountain environments, relief exerts a strong control on factors which control
SOC, e.g. through meso-climatic differences, but surface processes such as mass
wasting and water erosion. While the general relationships between environmental
variables and SOC are known, there is uncertainty regarding the specific quantitative
relationships between SOC and environmental variables. Particularly, the interaction
between geomorphic processes, soil thickness and soil carbon storage is not well
understood.
A priori reasoning suggests that spatial patterns of SOC in mountain areas are closely
correlated to the spatial patterns of terrain attributes that influence soil-forming
processes. In this study, we examined the relationships between SOC stocks and
climate, topography (elevation, slope, curvature,) and land use along an elevation
transect from Grindelwald Grund to the ridge of Kleine Scheidegg in the canton of
Bern. Soil samples were collected across a range of elevations, slope, curvature,
soil texture, vegetation types, and terrain positions. Topographic variables (e.g.
elevation, slope, curvature) were extracted from a high resolution digital elevation
model. SOC concentration of the soil samples was determined by Loss on Ignition.
For each sample, carbon densities Cdens (in g/cm2) were estimated for the topsoil
layer.
Our results show large differences in SOC across the landscape. The high spatial
variability is related most strongly to bed rock geology (lithology and soil type) and land use.
Somewhat surprisingly, site location relative to visible evidence of surface processes is of
minor importance. This lack of correlation at the scale of the study area appears
to indicate that geomorphic processes control the thickness of soils and thus C
content only on a smaller scale. This fact will be tested with a higher spatial sampling
density. Our results also indicate that SOC in mountainous environments is controlled
by a range of factors and that only some of them are affected by climate change. |
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