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| Titel |
Phosphorus transformations as a function of pedogenesis: A synthesis of soil phosphorus data using Hedley fractionation method |
| VerfasserIn |
X. Yang, W. M. Post |
| 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 ; 8, no. 10 ; Nr. 8, no. 10 (2011-10-17), S.2907-2916 |
| Datensatznummer |
250006162
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| Publikation (Nr.) |
 copernicus.org/bg-8-2907-2011.pdf |
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| Zusammenfassung |
| In spite of the importance of phosphorus (P) as a limiting nutrient in
terrestrial ecosystems, our understanding of terrestrial P dynamics and our
ability to model P cycling are hampered by the lack of consistent
measurements of soil P. The Hedley fractionation method provides a
comprehensive assessment of soil P and has been widely used in recent
decades. Here we expand an earlier study that summarized Hedley P data from
the literature to create a larger Hedley P database and further investigate
the relationships between distributions of different forms of P and the
stages of soil development. Our expanded Hedley P database generally
supports what the Walker and Syers (1976) conceptual model predicts: the
gradual decrease and eventual depletion of primary mineral P (mainly apatite
P); the continual increase and eventual dominance of occluded P; and the
overall decrease of total P during soil development. However the analysis
disagrees with Walker and Syers (1976) in that we found labile inorganic
P(Pi) and secondary mineral Pi (non-occluded P in Walker and Syers' model) to
be a significant fraction of total P throughout all soil orders with
different weathering stages. By analyzing the Hedley-labile P and vegetation
P demand, we found that the amount of labile P is much greater than
vegetation demand, even in highly weathered soils commonly considered P
limited. We conclude that labile P measured by Hedley fractionation method
should not be defined as plant available P since most of this labile P
likely ends up as immobilized by microbes. Our analysis of the database also
shows that carbon (C) and nitrogen (N) in soil organic matter are closely
linked in all soil orders, but P is decoupled from C and N in highly
weathered soils with larger variations of nitrogen:organic P (N:Po) ratio
and higher mean values of N:Po ratio, compared to slightly and
intermediately weathered soils. |
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