Universität zu Köln

Ahrens, Bernhard, Guggenberger, Georg, Rethemeyer, Janet, John, Stephan, Marschner, Bernd, Heinze, Stefanie ORCID: 0000-0002-2524-7355, Angst, Gerrit, Mueller, Carsten W., Koegel-Knabner, Ingrid, Leuschner, Christoph, Hertel, Dietrich, Bachmann, Joerg, Reichstein, Markus ORCID: 0000-0001-5736-1112 and Schrumpf, Marion (2020). Combination of energy limitation and sorption capacity explains C-14 depth gradients. Soil Biol. Biochem., 148. OXFORD: PERGAMON-ELSEVIER SCIENCE LTD. ISSN 0038-0717

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Abstract

During the last decade, a paradigmatic shift regarding which processes determine the persistence of soil organic matter (SOM) took place. The interaction between microbial decomposition and association of organic matter with the soil mineral matrix has been identified as a focal point for understanding the formation of stable SOM. Using an improved version of the vertically resolved SOM model COMISSION (Ahrens et al., 2015), this paper investigates the effect of a maximum sorption capacity (Q(max)) for mineral-associated organic matter (MAOM) formation and its interaction with microbial processes, such as microbial decomposition and microbial necromass production. We define and estimate the maximum sorption capacity Q(max) with quantile regressions between mineral-associated organic carbon (MAOC) and the clay plus silt (<20 mu m) content. In the COMISSION v2.0 model, plant- and microbial-derived dissolved organic matter (DOM) and dead microbial cell walls can sorb to mineral surfaces up to Q(max). MAOC can only be decomposed by microorganisms after desorption. We calibrated the COMISSION v2.0 model with data from ten different sites with widely varying textures and Q(max) values. COMISSION v2.0 was able to fit the MAOC and SOC depth profiles, as well as the respective C-14 gradients with soil depth across these sites. Using the generic set of parameters retrieved in the multi-site calibration, we conducted model experiments to isolate the effects of varying Q(max) point-of-entry of litter inputs, and soil temperature. Across the ten sites, the combination of depolymerization limitation of microorganisms due to substrate scarcity in the subsoil and the size of Q(max) explain C-14 depth gradients in OC.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Ahrens, Bernhard UNSPECIFIED UNSPECIFIED UNSPECIFIED Guggenberger, Georg UNSPECIFIED UNSPECIFIED UNSPECIFIED Rethemeyer, Janet UNSPECIFIED UNSPECIFIED UNSPECIFIED John, Stephan UNSPECIFIED UNSPECIFIED UNSPECIFIED Marschner, Bernd UNSPECIFIED UNSPECIFIED UNSPECIFIED Heinze, Stefanie UNSPECIFIED orcid.org/0000-0002-2524-7355 UNSPECIFIED Angst, Gerrit UNSPECIFIED UNSPECIFIED UNSPECIFIED Mueller, Carsten W. UNSPECIFIED UNSPECIFIED UNSPECIFIED Koegel-Knabner, Ingrid UNSPECIFIED UNSPECIFIED UNSPECIFIED Leuschner, Christoph UNSPECIFIED UNSPECIFIED UNSPECIFIED Hertel, Dietrich UNSPECIFIED UNSPECIFIED UNSPECIFIED Bachmann, Joerg UNSPECIFIED UNSPECIFIED UNSPECIFIED Reichstein, Markus UNSPECIFIED orcid.org/0000-0001-5736-1112 UNSPECIFIED Schrumpf, Marion UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-321754
DOI:	10.1016/j.soilbio.2020.107912
Journal or Publication Title:	Soil Biol. Biochem.
Volume:	148
Date:	2020
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Place of Publication:	OXFORD
ISSN:	0038-0717
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language SOIL ORGANIC-MATTER; EUROPEAN BEECH; CARBON; DECOMPOSITION; MODEL; STABILIZATION; RADIOCARBON; TRANSPORT; TURNOVER; CLIMATE Multiple languages Soil Science Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/32175