Impacts of reactive nitrogen (N) inputs on ecosystem carbon (C) dynamics are highly variable, and the underlying mechanisms remain unclear. Here, we proposed a new conceptual framework that integrates plant, microbial and geochemical mechanisms to reconcile diverse and contrasting impacts of N on soil C. This framework was tested using long-term N enrichment and acid addition experiments in a Mongolian steppe grassland. Distinct mechanisms could explain effects of N on particulate and mineral-associated soil C pools, potentially explaining discrepancies among previous N addition studies. While plant production predominated particulate C changes, N-induced soil acidification strongly affected mineral-associated C through decreased microbial growth and pH-sensitive associations between iron and aluminium minerals and C. Our findings suggest that effects of N-induced acidification on microbial respiration and geochemical properties should be included in Earth system models that predict ecosystem C budgets under future N deposition/input scenarios.
Reconciling multiple impacts of nitrogen enrichment on soil carbon: plant, microbial and geochemical controls.
C. Ye,Dima Chen,S. Hall,Shang Pan,Xuebin Yan,Tongshuo Bai,Hui Guo,Yi Zhang,Yongfei Bai,Shuijin Hu
Published 2018 in Ecology Letters
ABSTRACT
PUBLICATION RECORD
- Publication year
2018
- Venue
Ecology Letters
- Publication date
2018-08-01
- Fields of study
Medicine, Environmental Science
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
CITATION MAP
EXTRACTION MAP
CLAIMS
CONCEPTS
- earth system models
Large-scale models used to simulate coupled climate, ecosystem, and biogeochemical processes.
Aliases: ESMs
- geochemical properties
Soil chemical and mineral characteristics that influence carbon stabilization.
Aliases: soil geochemistry, geochemical conditions
- integrated conceptual framework
A proposed framework that links plant, microbial, and geochemical pathways to interpret nitrogen effects on soil carbon.
Aliases: conceptual framework, framework
- iron and aluminium minerals
Soil mineral phases containing iron and aluminium that can bind organic carbon.
Aliases: Fe and Al minerals, iron/aluminium minerals
- microbial growth
The increase or accumulation of microbial biomass in soil.
Aliases: microbial biomass growth
- microbial respiration
The release of carbon dioxide by soil microbes during decomposition.
Aliases: soil respiration
- mineral-associated soil carbon pool
The soil carbon fraction bound to mineral surfaces and fine particles.
Aliases: mineral-associated C, MAOC
- nitrogen enrichment
Experimental addition of reactive nitrogen to the grassland ecosystem.
Aliases: N enrichment, nitrogen addition, reactive nitrogen input
- particulate soil carbon pool
The soil carbon fraction associated with particulate organic matter.
Aliases: particulate C, POM-associated carbon
- plant production
Aboveground and belowground plant biomass generation in the steppe grassland.
Aliases: primary production, plant biomass production
REFERENCES
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