To the top

Page Manager: Webmaster
Last update: 9/11/2012 3:13 PM

Tell a friend about this page
Print version

Decoupling of priming and… - University of Gothenburg, Sweden Till startsida
Sitemap
To content Read more about how we use cookies on gu.se

Decoupling of priming and microbial N mining during a short-term soil incubation

Journal article
Authors Birgit Wild
J. Li
Johanna Pihlblad
P. Bengtson
Tobias Rütting
Published in Soil Biology and Biochemistry
Volume 129
Pages 71-79
ISSN 0038-0717
Publication year 2019
Published at Department of Earth Sciences
Pages 71-79
Language en
Links dx.doi.org/10.1016/j.soilbio.2018.1...
Keywords Chitin, Decomposition, Extracellular enzymes, Lignin, Phospholipid fatty acids, Protein, Carbon, Depolymerization, Enzymes, Fatty acids, Microorganisms, Phospholipids, Proteins, C and N cycling, Lignin depolymerization, Priming effects, Protein depolymerization, Soil respiration, SOM decomposition, Soils
Subject categories Soil Science, Earth and Related Environmental Sciences

Abstract

Soil carbon (C) and nitrogen (N) availability depend on the breakdown of soil polymers such as lignin, chitin, and protein that represent the major fraction of soil C and N but are too large for immediate uptake by plants and microorganisms. Microorganisms may adjust the production of enzymes targeting different polymers to optimize the balance between C and N availability and demand, and for instance increase the depolymerization of N-rich compounds when C availability is high and N availability low (“microbial N mining”). Such a mechanism could mitigate plant N limitation but also lie behind a stimulation of soil respiration frequently observed in the vicinity of plant roots (“priming effect”). We here compared the effect of increased C and N availability on the depolymerization of native bulk soil organic matter (SOM), and of 13C-enriched lignin, chitin, and protein added to the same soil in two complementary ten day microcosm incubation experiments. A significant reduction of chitin depolymerization (described by the recovery of chitin-derived C in the sum of dissolved organic, microbial and respired C) upon N addition indicated that chitin was degraded to serve as a microbial N source under low-N conditions and replaced in the presence of an immediately available alternative. Protein and lignin depolymerization in contrast were not affected by N addition. Carbon addition enhanced microbial N demand and SOM decomposition rates, but significantly reduced lignin, chitin, and protein depolymerization. Our findings contrast the hypothesis of increased microbial N mining as a key driver behind the priming effect and rather suggest that C addition promoted the mobilization of other soil C pools that replaced lignin, chitin, and protein as microbial C sources, for instance by releasing soil compounds from mineral bonds. We conclude that SOM decomposition is interactively controlled by multiple mechanisms including the balance between C vs N availability. Disentangling these controls will be crucial for understanding C and N cycling on an ecosystem scale. © 2018 The Authors

Page Manager: Webmaster|Last update: 9/11/2012
Share:

The University of Gothenburg uses cookies to provide you with the best possible user experience. By continuing on this website, you approve of our use of cookies.  What are cookies?