Chemical composition of the organic matter in forest soils: The humus layer
- 1 January 1988
- journal article
- research article
- Published by Wiley in Journal of Plant Nutrition and Soil Science
- Vol. 151 (5), 331-340
- https://doi.org/10.1002/jpln.19881510512
Abstract
Decomposition and humification were studied within three types of forest humus (mull, moder, and mor) by means of CPMAS 13C NMR spectroscopy combined with degradative methods. The NMR data show that O‐alkyl carbon decreases in all soils, and alkyl as well as carboxyl carbon increase as depth and decomposition increase; the percentage of aromatic carbon remains constant at about 25%. With increasing depth the amount of carbon that can be identified as belonging to specific compound classes by wet chemical methods decreases from 60% to 40%. Microbial polysaccharides and the proportion of non polysaccharide O‐alkyl carbon increase with depth. A selective preservation of recalcitrant, condensed lignin structural units is also observed. In order to relate the spectroscopic and chemical data from investigations of whole soils with studies of humification, samples were fractionated into fulvic acid, humic acid, and humin fractions. The fulvic acid fraction contains large concentrations of carbohydrates irrespective of the soil horizon. The humic acid fraction contains less polysaccharides, but high amounts of alkyl carbon and aromatic structures. The percentage of aromatic carbon existing in the humic acid fraction increases with depth, probably reflecting the amount and degree of oxidative decomposition of lignin. A loss of methoxyl and phenolic groups is evident in the 13C NMR spectra of the humic acid fraction. The humin fraction resembles relatively unchanged plant‐derived materials as evident from the lignin parameters and carbohydrate contents. All the observed data seem to indicate that humic acids originate form oxidative degradation of humin or plant litter.Keywords
This publication has 22 references indexed in Scilit:
- CHEMICAL COMPOSITION OF THE ORGANIC MATTER IN FOREST SOILSSoil Science, 1988
- CHEMICAL COMPOSITION OF THE ORGANIC MATTER IN FOREST SOILSSoil Science, 1988
- Decomposition in forest humus layers studied by CPMAS 13C NMR, pyrolysis-field ionization-mass spectrometry and CuO oxidationScience of The Total Environment, 1987
- Organic compounds in cryofolists developed on limestone under subalpine coniferous forest, BavariaGeoderma, 1985
- CP‐MAS‐ 13 C‐NMR‐Spektren organischer Lagen einer TangelrendzinaJournal of Plant Nutrition and Soil Science, 1985
- Intermediate Steps pf Microbial Lignin Degradation as Elucidated by13C NMR Spectroscopy of Specifically13C-Enriched DHP-LigninsHolzforschung, 1985
- Decomposition kinetics of straw saccharides and synthesis of microbial saccharides under field conditionsEuropean Journal of Soil Science, 1984
- Decomposition Dynamics of Fine Roots in Forested EcosystemsOikos, 1984
- Incorporation of a Wide Variety of Organic Substrate Carbons into Soil Biomass as Estimated by the Fumigation ProcedureSoil Science Society of America Journal, 1981
- Short NoteHolzforschung, 1979