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Predicting carbon content in illitic clay fractions from surface area, cation exchange capacity and dithionite‐extractable iron
Author(s) -
Kahle M.,
Kleber M.,
Jahn R.
Publication year - 2002
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1046/j.1365-2389.2002.00487.x
Subject(s) - chemistry , dithionite , clay minerals , cation exchange capacity , silicate , total organic carbon , loess , carbon fibers , fraction (chemistry) , mineralogy , environmental chemistry , geology , soil water , soil science , materials science , chromatography , composite material , biochemistry , organic chemistry , composite number , enzyme , geomorphology
Summary We used the specific surface area (SSA), the cation exchange capacity (CEC) and the content of dithionite‐extractable iron (Fe d ) to predict the content of organic carbon in illitic clay fractions of topsoils from loess. We determined SSA (BET‐N 2 method) and CEC of clay fractions after removing organic C or reducing oxides or both. The CEC and the SSA of the carbon‐ and oxide‐free clay fraction explained 56% and 54% of the variation in C content, respectively. The Fe d content of the clay fractions was strongly and negatively related to the C content, and with the SSA of the carbon‐free clay fraction it predicted C content almost completely ( R 2 = 0.96). The results indicate that the amount of cations adhering to the silicate clay minerals and the size of the silicate mineral surface area are important properties of the mineral phase for the storage potential of C. The reason for the negative relation between iron oxides and C content remains unclear.