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Visualizing the transfer of organic matter from decaying plant residues to soil mineral surfaces controlled by microorganisms

Vidal, Alix; Klöffel, Tobias; Guigue, Julien; Angst, Gerrit; Steffens, Markus; Hoeschen, Carmen and Mueller, Carsten W. (2021) Visualizing the transfer of organic matter from decaying plant residues to soil mineral surfaces controlled by microorganisms. Soil Biology and Biochemistry, 160, p. 108347.

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Document available online at: https://www.sciencedirect.com/science/article/abs/pii/S0038071721002200


Summary

The interface between decaying plant residues and soil minerals represents an essential soil microenvironment at which soil organic matter forms. The high amount of microbial products and residues within this hot spot of microbial activity fosters the formation of mineral-associated organic matter. Besides classical quantitative analyses, our understanding of processes controlling soil organic matter formation greatly benefits from microscopic observations and measurements, which provide spatially resolved information at a meaningful scale for microbial processes and for the association between organic and mineral particles. We studied carbon and nitrogen transfer from fresh-plant residues to the mineral soil, through a litter decomposition experiment in an artificial soil mixture. Needles of Norway spruce (Picea abies L.) were placed in microbatch containers filled with an artificial soil mixture free of soil organic matter. Containers were buried in fresh organic layer material from a Norway spruce stand and incubated for 14 and 42 days. We applied nanoscale secondary ion mass spectroscopy (NanoSIMS) to investigate the spatial distribution of mineral and organic compounds at the needle vicinity and into the mineral soil (0–550 μm from the needle). After 14 days, we depicted the formation of mineral-associated organic matter in the surrounding of the decaying needles. After 42 days, we observed substantial colonization of the needles and the detritusphere by saprotrophic fungi. The fungal hyphae extended into the mineral matrix of the artificial soil acting as vectors for the transfer of litter-derived carbon and nitrogen into the bulk soil. This resulted in an increase of the area covered by organic matter in the detritusphere, with up to 10% of the total investigated area classified as organic matter closely associated with mineral surfaces. Our results provide evidence that the carbon and nitrogen derived from litter decomposition transformed by microorganisms is transferred as mineral-associated organic matter, heterogeneously distributed from the litter source, and still detected 550 μm away from the latter. The close association of newly formed soil organic matter and fine sized minerals suggests that the formation of mineral-associated OM and likely also microaggregates is directly driven by microbial activity in the vicinity of hot spots for plant carbon input (e.g. the detritusphere).


EPrint Type:Journal paper
Keywords:Norway spruce, Artificial soil mixture, NanoSIMS, Mineral-associated organic matter, Microaggregates, Saprotrophic fungi, Abacus, FiBL10125
Agrovoc keywords:
Language
Value
URI
English
organic matter
http://aims.fao.org/aos/agrovoc/c_5387
English
saprotroph -> saprophytes
http://aims.fao.org/aos/agrovoc/c_14083
English
Fungi
http://aims.fao.org/aos/agrovoc/c_3145
Subjects: Knowledge management > Research methodology and philosophy > Specific methods
Soil > Nutrient turnover
Research affiliation: Switzerland > FiBL - Research Institute of Organic Agriculture Switzerland > Soil > Soil quality > Soil functions
Czech Republic > Other institutions
Germany > University of Munich - TUM
Sweden > University of Uppsala
DOI:10.1016/j.soilbio.2021.108347
Deposited By: Forschungsinstitut für biologischen Landbau, FiBL
ID Code:42759
Deposited On:09 Nov 2021 08:28
Last Modified:11 Jan 2022 12:43
Document Language:English
Status:Published
Refereed:Peer-reviewed and accepted

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