HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (16) Citing Articles via Google Scholar Google Scholar Articles by Kahle, M. Articles by Jahn, R. Search for Related Content PubMed Articles by Kahle, M. Articles by Jahn, R. GeoRef GeoRef Citation Agricola Articles by Kahle, M. Articles by Jahn, R. Related Collections Carbon Sequestration Isotopes Soil Organic Matter

DIVISION S-2—SOIL CHEMISTRY

Carbon Storage in Coarse and Fine Clay Fractions of Illitic Soils

^a Institut für Bodenkunde und Pflanzenernährung, Martin-Luther-Universität Halle-Wittenberg, Weidenplan 14, 06108 Halle, Germany
^b Earth Science Division, Lawrence Berkeley National Lab., MS 90-1116, Berkeley, CA 94720

^* Corresponding author (kahle{at}landw.uni-halle.de).

The storage of organic C in coarse (0.2–2 µm) and fine (<0.2 µm) clay fractions of illitic topsoils from loess was investigated in terms of the effect of particle size and mineral phase properties. We compared (i) C functional groups by ¹³C nuclear magnetic resonance spectroscopy (NMR), (ii) the stable C isotope ratio (¹³ C ratio) of organic pools, and (iii) residence time of C by ¹⁴C analyses. To investigate relationships between C storage and the size of mineral surface area or the amount of hydrous oxides, specific surface areas (SSAs, BET-N₂ method) and the content of dithionite-extractable Fe (Fe_d) were analyzed. The chemistry of the organic matter stored in clay subfractions was different. Compared with coarse clay, fine clay contained relatively (i) more ketonic/aldehyde, carboxyl and phenolic C, and (ii) less anomeric, O-alkyl, and methoxyl/N-alkyl C, and had (iii) a lower C content and C/N ratio and (iv) a higher ¹³C ratio. In 11 out of 14 fractions, C had turnover times of few centuries or less. In fine clay, the increase in SSA resulting from oxidation of organic matter explained 66% of the variation in C content, in coarse clay 97%. We calculated loadings of mineral surface area with C and Fe_d. Carbon loading exceeded Fe_d loading in coarse clay while it was of the same range in fine clay. The results may be interpreted as an indication that a certain portion of the mineral surface area controls the C content in both clay subfractions. The character of the important surface may differ between the subfractions.

Abbreviations: CPMAS, cross polarization magic-angle spinning • Fe_d, dithionite-extractable Fe • NMR, nuclear magnetic resonance • SSA, specific surface area • SSA(c), specific surface area of clay fraction after C removal • SSA, increase in SSA after removal of organic matter • ¹³C ratio, stable C isotope ratio

This article has been cited by other articles:

				C. Rasmussen, M. S. Torn, and R. J. Southard Mineral Assemblage and Aggregates Control Carbon Dynamics in a California Conifer Forest Soil Sci. Soc. Am. J., September 29, 2005; 69(6): 1711 - 1721. [Abstract] [Full Text] [PDF]

				K. M. Dontsova and J. M. Bigham Anionic Polysaccharide Sorption by Clay Minerals Soil Sci. Soc. Am. J., June 2, 2005; 69(4): 1026 - 1035. [Abstract] [Full Text] [PDF]

				R. Mikutta, M. Kleber, K. Kaiser, and R. Jahn Review: Organic Matter Removal from Soils using Hydrogen Peroxide, Sodium Hypochlorite, and Disodium Peroxodisulfate Soil Sci. Soc. Am. J., January 1, 2005; 69(1): 120 - 135. [Abstract] [Full Text] [PDF]