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

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Schulten, H.-R. Articles by Leinweber, P. Search for Related Content PubMed Articles by Schulten, H.-R. Articles by Leinweber, P. Agricola Articles by Schulten, H.-R. Articles by Leinweber, P.

Dithionite-Citrate-Bicarbonate-Extractable Organic Matter in Particle-Size Fractions of a Haplaquoll

Fachhochschule Fresenius, Dep. of Trace Analysis, Dambachtal 20, 65193 Wiesbaden, Germany

P. Leinweber

Inst. for Structural Analysis and Planning in Areas of Intensive Agriculture (ISPA), Univ. Vechta, P.O. Box 1553, Driverstrasse 22, 49364 Vechta, Germany

*Corresponding author.

ABSTRACT

The influence of the dithionite-citrate-bicarbonate (DCB) extraction on soil organic matter (SOM) in five particle-size fractions of a Haplaquoll was studied by pyrolysis-field ionization mass spectrometry. By treatment with DCB, 4 to 19 g kg^–1 of organic C (C_dcb; 17.8–44.4% of total C), 2.2 to 20.3 g kg^–1 of Fe (Fe_dcb; 13.6–29.7% of total Fe), and 0.4 to 8.4 g kg^–1 of Al (Al_dcb; 0.6–8.0% of total Al) were extracted from the size fractions. The pyrolysis-field ionization mass spectra recorded before and after DCB extraction and the proportions of six important compound classes of SOM showed that lipids, alkylaromatics, and lignin dimers were preferentially extracted. In the extraction residues of clay, fine silt, and medium silt, increases in total ion intensities, weight-averaged molecular weights of the pyrolysate, and characteristic shifts in the pyrolysis thermograms toward lower temperatures were observed. These properties indicated a general destabilization of the SOM structure due to DCB extraction. We explained these results by the solubility of these SOM constituents in alkali or by associations with pedogenic oxides that stabilized the SOM structure. The results pointed also to unknown, possibly selective, losses of C species when DCB extraction is used to improve the quality of solid-state (cross polarization/magic angle spinning)-¹³C nuclear magnetic resonance spectra.

Received for publication February 10, 1994.