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Use of 13 C to monitor soil organic matter transformations caused by a simulated forest fire
Author(s) -
Fernandez Irene,
Cabaneiro Ana,
GonzálezPrieto Serafín J.
Publication year - 2004
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.1345
Subject(s) - chemistry , humin , mineralization (soil science) , environmental chemistry , organic matter , biodegradation , soil organic matter , lolium perenne , soil water , humic acid , soil science , botany , organic chemistry , nitrogen , environmental science , fertilizer , poaceae , biology
Soil organic matter (SOM) transformations caused by heating were analyzed using the stable carbon isotope 13 C as a tracer to follow C mineralization dynamics and C transfers between different organic compartments. A 13 C‐labelled soil, obtained by incorporation of 13 C‐enriched Lolium perenne phytomass into a pine forest soil, was heated for 10 min at 385°C to reproduce conditions typical of a forest fire and changes in total C content, potential C mineralization activity and C distribution between the different soil organic fractions were determined. Changes caused by heating on the potential soil C mineralization, determined by laboratory aerobic incubation, reveal alterations to the SOM biodegradability; some stabilized SOM showed an increase in biodegradability, whereas less stabilized SOM became more resistant to microorganisms. Chemical fractionations of SOM allowed us to monitor changes in its composition. As a consequence of heating, the less polymerized humic fractions were the most strongly affected, with the total disappearance of fulvic acids. A significant increase in the quantity and degree of polymerization of the humic acids at the expense of other more 13 C‐enriched substances was also found. Finally, a large decrease in humin was observed, its solubilizable part disappearing completely, probably as a consequence of the incorporation of the byproducts into the free organic matter fraction. Copyright © 2004 John Wiley & Sons, Ltd.