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| Titel |
Soil organic matter dynamics under different land use in grasslands in Inner Mongolia (northern China) |
| VerfasserIn |
L. Zhao, W. Wu, X. Xu, Y. Xu |
| 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. 18 ; Nr. 11, no. 18 (2014-09-22), S.5103-5113 |
| Datensatznummer |
250117605
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| Publikation (Nr.) |
 copernicus.org/bg-11-5103-2014.pdf |
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| Zusammenfassung |
| We examined bulk soil properties and molecular biomarker distributions in
surface soils from Inner Mongolian grasslands in order to understand the
responses of soil organic matter to different land use. A total of 16 soils
were collected from severely degraded grassland by overgrazing (DG), native
grassland without apparent anthropogenic disturbance (NG),
groundwater-sustaining grassland (GG) and restored grassland from previous
potato cropland (RG). Compared to NG, soil organic carbon content was lower
by 50% in DG, but higher by six-fold in GG and one-fold in RG. The
δ13C values of soil organic carbon were
–24.2 ± 0.6‰ in DG, –24.9 ± 0.6‰ in NG,
–25.1 ± 0.1‰ in RG and –26.2 ± 0.6‰ in GG,
reflecting different degradation degrees of soil organic matter or different
water use efficiencies. The soils in DG contained the lowest abundance of
aliphatic lipids (n-alkanes, n-alkanols, n-alkanoic acids, ω-hydroxylalkanoic acids and α-hydroxyalkanoic acids) and lignin-phenols, suggesting selective
removal of these biochemically recalcitrant biomarkers with grassland
degradation by microbial respiration or wind erosion. Compared to NG, the
soils in GG and RG increased ω-hydroxylalkanoic acids by
60–70%, a biomarker for suberin from roots, and increased α-hydroxylalkanoic acids by 10–20%, a biomarker for both cutin and
suberin. Our results demonstrate that the groundwater supply and
cultivation–restoration practices in Inner Mongolian grasslands not only
enhance soil organic carbon sequestration, but also change the proportions of
shoot- versus root-derived carbon in soils. This finding has important
implications for the global carbon cycle since root-derived aliphatic carbon
has a longer residence time than the aboveground tissue-derived carbon in
soils. |
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