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Research article - Peer-reviewed, 2016

Differences in substrate use efficiency: impacts of microbial community composition, land use management, and substrate complexity

Bölscher, Tobias; Wadsö, Lars; Börjesson, Gunnar; Herrmann, Anke;

Abstract

Microbial substrate use efficiency is an important property in process-based soil organic matter models, but is often assumed to be constant in mechanistic models. However, previous studies question if a constant efficiency is appropriate, in particular when evaluating carbon (C) cycling across temperatures and various substrates. In the present study, we evaluated the relation between substrate use efficiency, microbial community composition and substrate complexity in contrasting long-term management regimes (47-49 years of either arable, ley farming, grassland, or forest systems). Microbial community composition was assessed by phospholipid fatty acid analysis and three indices of substrate use efficiencies were considered: (i) thermodynamic efficiency, (ii) calorespirometric ratio, and (iii) metabolic quotient. Three substrates, d-glucose, l-alanine, or glycogen, varying in complexity, were added separately to soils, and heat production as well as C mineralization was determined over a 32-h incubation period at 12.5 A degrees C. Microbial communities from forest systems were most efficient in utilizing substrates, supporting our hypothesis that maturing ecosystems become more efficient. These changes in efficiency were linked to microbial community composition with fungi and Gram-negative bacteria being important biomarkers. Despite our initial hypothesis, complex substrate such as glycogen was utilized most efficiently. Our findings emphasize that differences in land use management systems as well as the composition of soil organic matter need to be considered when modelling C dynamics in soils. Further research is required to establish and evaluate appropriate proxies for substrate use efficiencies in various ecosystems.

Keywords

Microbial carbon use efficiency; Microbial community; Land use; Substrate complexity; Isothermal calorimetry

Published in

Biology and Fertility of Soils

2016, volume: 52, number: 4, pages: 547-559
Publisher: SPRINGER

Authors' information

Bölscher, Tobias
Swedish University of Agricultural Sciences, The Department of Chemistry and Biotechnology
Wadsö, Lars
Lund University
Swedish University of Agricultural Sciences, Department of Soil and Environment
Swedish University of Agricultural Sciences, The Department of Chemistry and Biotechnology

Associated SLU-program

SLU Network Plant Protection

UKÄ Subject classification

Soil Science

Publication Identifiers

DOI: https://doi.org/10.1007/s00374-016-1097-5

URI (permanent link to this page)

https://res.slu.se/id/publ/77244