TY - JOUR
T1 - Stabilisation of soil organic matter by interactions with minerals as revealed by mineral dissolution and oxidative degradation
AU - Eusterhues, Karin
AU - Rumpel, Cornelia
AU - Kleber, Markus
AU - Kögel-Knabner, Ingrid
N1 - Funding Information:
This project is financially supported by the priority program 1090 “Soils as sinks and sources for CO 2 - mechanisms and regulation of carbon stabilisation in soils” of the Deutsche Forschungsgemeinschaft. The radiocarbon analyses were carried out at the Leibniz Laboratory, Universität Kiel. We thank Maria Greiner for support in the laboratory and Kai Uwe Totsche for helpful discussion. Valuable comments were provided by Jeff Baldock, an anonymous reviewer and Claude Largeau.
PY - 2003
Y1 - 2003
N2 - Soil organic matter is known to contain a stable fraction with an old radiocarbon age. Size and stabilisation processes leading to the formation of this old soil carbon pool are still unclear. Our study aims to differentiate old organic matter from young and labile carbon compounds in two acid forest soils (dystric cambisol, haplic podzol). To identify such fractions soil samples were exposed to oxidation with Na2S2O8 and to dissolution by hydrofluoric acid (HF). A negative correlation between 14C activity and carbon release after dissolution of the mineral matrix by HF indicates a strong association of stabilised carbon compounds with the mineral phase. A negative correlation between the 14C activity and the relative proportion of carbon resistant to oxidation by Na 2S2O8 shows that young carbon is removed preferentially by this treatment. The fraction remaining after oxidation represents a certain stabilised, long residence time carbon pool. This old fraction comprises between 1 and 30% of the total soil organic carbon in the surface horizons, but reaches up to 80% in the sub-surface horizons. Old OC is mainly stabilised by organo-mineral associations with clay minerals and/or iron oxides, whereas intercalation in clay minerals was not found to be important.
AB - Soil organic matter is known to contain a stable fraction with an old radiocarbon age. Size and stabilisation processes leading to the formation of this old soil carbon pool are still unclear. Our study aims to differentiate old organic matter from young and labile carbon compounds in two acid forest soils (dystric cambisol, haplic podzol). To identify such fractions soil samples were exposed to oxidation with Na2S2O8 and to dissolution by hydrofluoric acid (HF). A negative correlation between 14C activity and carbon release after dissolution of the mineral matrix by HF indicates a strong association of stabilised carbon compounds with the mineral phase. A negative correlation between the 14C activity and the relative proportion of carbon resistant to oxidation by Na 2S2O8 shows that young carbon is removed preferentially by this treatment. The fraction remaining after oxidation represents a certain stabilised, long residence time carbon pool. This old fraction comprises between 1 and 30% of the total soil organic carbon in the surface horizons, but reaches up to 80% in the sub-surface horizons. Old OC is mainly stabilised by organo-mineral associations with clay minerals and/or iron oxides, whereas intercalation in clay minerals was not found to be important.
UR - http://www.scopus.com/inward/record.url?scp=0344927805&partnerID=8YFLogxK
U2 - 10.1016/j.orggeochem.2003.08.007
DO - 10.1016/j.orggeochem.2003.08.007
M3 - Article
AN - SCOPUS:0344927805
SN - 0146-6380
VL - 34
SP - 1591
EP - 1600
JO - Organic Geochemistry
JF - Organic Geochemistry
IS - 12
ER -