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| Titel |
Intra- versus inter-site macroscale variation in biogeochemical properties along a paddy soil chronosequence |
| VerfasserIn |
C. Mueller-Niggemann, A. Bannert, M. Schloter, E. Lehndorff, L. Schwark |
| 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 ; 9, no. 3 ; Nr. 9, no. 3 (2012-03-30), S.1237-1251 |
| Datensatznummer |
250006858
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| Publikation (Nr.) |
 copernicus.org/bg-9-1237-2012.pdf |
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| Zusammenfassung |
| In order to assess the intrinsic heterogeneity of paddy soils, a set of
biogeochemical soil parameters was investigated in five field replicates of
seven paddy fields (50, 100, 300, 500, 700, 1000, and 2000 yr of wetland
rice cultivation), one flooded paddy nursery, one tidal wetland (TW), and
one freshwater site (FW) from a coastal area at Hangzhou Bay, Zhejiang
Province, China. All soils evolved from a marine tidal flat substrate due to
land reclamation. The biogeochemical parameters based on their properties
were differentiated into (i) a group behaving conservatively (TC, TOC, TN,
TS, magnetic susceptibility, soil lightness and colour parameters, δ13C,
δ15N, lipids and n-alkanes) and (ii) one encompassing more labile
properties or fast cycling components (Nmic, Cmic, nitrate,
ammonium, DON and DOC). The macroscale heterogeneity in paddy soils was
assessed by evaluating intra- versus inter-site spatial variability of
biogeochemical properties using statistical data analysis (descriptive,
explorative and non-parametric). Results show that the intrinsic
heterogeneity of paddy soil organic and minerogenic components per field is
smaller than between study sites. The coefficient of variation (CV) values
of conservative parameters varied in a low range (10% to 20%),
decreasing from younger towards older paddy soils. This indicates a
declining variability of soil biogeochemical properties in longer used
cropping sites according to progress in soil evolution. A generally higher
variation of CV values (>20–40%) observed for labile parameters implies
a need for substantially higher sampling frequency when investigating these
as compared to more conservative parameters. Since the representativeness of
the sampling strategy could be sufficiently demonstrated, an investigation
of long-term carbon accumulation/sequestration trends in topsoils of the
2000 yr paddy chronosequence under wetland rice cultivation restricted was
conducted. Observations cannot be extrapolated to global scale but with
coastal paddy fields developed on marine tidal flat substrates after land
reclamation in the Zhejiang Province represent a small fraction (<1%) of
the total rice cropping area. The evolutionary trend showed that the
biogeochemical signatures characteristic for paddy soils were fully
developed in less than 300 yr since onset of wetland rice cultivation. A
six-fold increase of topsoil TOC suggests a substantial gain in CO2
sequestration potential when marine tidal wetland substrate developed to
2000 yr old paddy soil. |
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