![Hier klicken, um den Treffer aus der Auswahl zu entfernen](images/unchecked.gif) |
Titel |
The association of soil organic matter with mineral surfaces depends on clay
content in an arable Cambisol |
VerfasserIn |
Steffen A. Schweizer, Angelika Koelbl, Carmen Hoeschen, Carsten W. Mueller, Ingrid Koegel-Knabner |
Konferenz |
EGU General Assembly 2017
|
Medientyp |
Artikel
|
Sprache |
en
|
Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 19 (2017) |
Datensatznummer |
250141236
|
Publikation (Nr.) |
EGU/EGU2017-4719.pdf |
|
|
|
Zusammenfassung |
The amount and distribution of mineral-associated soil organic matter (MOM) depends on the
availability of adsorptive mineral surface area. In soils with low content of fine-sized mineral
particles, the available mineral surface is limited in comparison to soils with high content of
fine-sized mineral particles. Accordingly, the spatial distribution of MOM from soils with
various contents of fine-sized mineral particles should reflect different structural organization
of organo-mineral associations. In this study, we analyzed MOM and further indicators
of its binding in the topsoil (020 cm) of an arable Cambisol. The sampled site
showed a gradient in the content of clay-sized particles (6-35 %) under similar soil
management and biomass input. We obtained fine silt-sized (26.3 μm) and clay-sized
(0.22 μm) mineral-associated (>1.6 g cm3) fractions from a combined density
and size fractionation. We measured solid-state 13C nuclear magnetic resonance
spectra and analyzed the specific surface area of the fractions by N2-BET with and
without NaOCl oxidation. The spatial distribution of MOM was determined by
nanoscale secondary ion mass spectrometry (NanoSIMS) at a lateral resolution of
approximately 100 nm. We found that the mineral-associated carbon concentration of
the fine silt and clay-sized fractions decreased from 80 to 40 mg g−1 when the
content of clay-sized particles increased from 6 to 15 %. In the clay-rich soils the
mineral-associated carbon remained constant at approximately 40 mg g−1 for higher
contents of clay-sized particles from 15 to 30 %. In addition, the 12C and 12C14N ion
distributions obtained from NanoSIMS indicated a much higher coverage of mineral surface
with MOM in the sandy soils than in the clay-rich soils. Our data shows that both the
concentration and coverage of MOM is increased in soils with a lower content of
fine-sized mineral particles, when the input of organic material to the soil is similar. |
|
|
|
|
|