A stoichiometric approach to estimate sources of mineral-associated soil organic matter

© 2023 John Wiley & Sons Ltd..

Mineral-associated soil organic matter (MAOM) is the largest, slowest cycling pool of carbon (C) in the terrestrial biosphere. MAOM is primarily derived from plant and microbial sources, yet the relative contributions of these two sources to MAOM remain unresolved. Resolving this issue is essential for managing and modeling soil carbon responses to environmental change. Microbial biomarkers, particularly amino sugars, are the primary method used to estimate microbial versus plant contributions to MAOM, despite systematic biases associated with these estimates. There is a clear need for independent lines of evidence to help determine the relative importance of plant versus microbial contributions to MAOM. Here, we synthesized 288 datasets of C/N ratios for MAOM, particulate organic matter (POM), and microbial biomass across the soils of forests, grasslands, and croplands. Microbial biomass is the source of microbial residues that form MAOM, whereas the POM pool is the direct precursor of plant residues that form MAOM. We then used a stoichiometric approach-based on two-pool, isotope-mixing models-to estimate the proportional contribution of plant residue (POM) versus microbial sources to the MAOM pool. Depending on the assumptions underlying our approach, microbial inputs accounted for between 34% and 47% of the MAOM pool, whereas plant residues contributed 53%-66%. Our results therefore challenge the existing hypothesis that microbial contributions are the dominant constituents of MAOM. We conclude that biogeochemical theory and models should account for multiple pathways of MAOM formation, and that multiple independent lines of evidence are required to resolve where and when plant versus microbial contributions are dominant in MAOM formation.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:30

Enthalten in:

Global change biology - 30(2024), 1 vom: 04. Jan., Seite e17092

Sprache:

Englisch

Beteiligte Personen:

Chang, Yi [VerfasserIn]
Sokol, Noah W [VerfasserIn]
van Groenigen, Kees Jan [VerfasserIn]
Bradford, Mark A [VerfasserIn]
Ji, Dechang [VerfasserIn]
Crowther, Thomas W [VerfasserIn]
Liang, Chao [VerfasserIn]
Luo, Yiqi [VerfasserIn]
Kuzyakov, Yakov [VerfasserIn]
Wang, Jingkuan [VerfasserIn]
Ding, Fan [VerfasserIn]

Links:

Volltext

Themen:

7440-44-0
Carbon
Journal Article
Meta-analysis
Mineral-associated organic matter
Minerals
Particulate organic matter
Plant carbon
Soil
Soil carbon
Soil organic matter dynamics

Anmerkungen:

Date Completed 29.01.2024

Date Revised 29.01.2024

published: Print

Citation Status MEDLINE

doi:

10.1111/gcb.17092

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM367638940