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| Titel |
Insights into biogeochemical cycling from a soil evolution model and long-term chronosequences |
| VerfasserIn |
M. O. Johnson, M. Gloor, M. J. Kirkby  , J. Lloyd |
| 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 ; 11, no. 23 ; Nr. 11, no. 23 (2014-12-10), S.6873-6894 |
| Datensatznummer |
250117723
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| Publikation (Nr.) |
 copernicus.org/bg-11-6873-2014.pdf |
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| Zusammenfassung |
| Despite the importance of soil processes for global biogeochemical cycles,
our capability for predicting soil evolution over geological timescales is
poorly constrained. We attempt to probe our understanding and predictive
capability of this evolutionary process by developing a mechanistic soil
evolution model, based on an existing model framework, and comparing the
predictions with observations from soil chronosequences in Hawaii. Our soil
evolution model includes the major processes of pedogenesis: mineral
weathering, percolation of rainfall, leaching of solutes, surface erosion,
bioturbation, the effects of vegetation in terms of organic matter input and
nutrient cycling and can be applied to various bedrock compositions and
climates. The specific properties the model simulates over timescales of tens
to hundreds of thousand years are, soil depth, vertical profiles of elemental
composition, soil solution pH and organic carbon distribution. We demonstrate
with this model the significant role that vegetation plays in accelerating
the rate of weathering and hence soil profile development. Comparisons with
soils that have developed on Hawaiian basalts reveal a remarkably good
agreement with Na, Ca and Mg profiles suggesting that the model captures well
the key components of soil formation. Nevertheless, differences between
modelled and observed K and P are substantial. The fact that these are
important plant nutrients suggests that a process likely missing from our
model is the active role of vegetation in selectively acquiring nutrients.
This study therefore indirectly indicates the valuable role that vegetation
can play in accelerating the weathering and thus release of these globally
important nutrients into the biosphere. |
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