Anthropogenic nitrogen (N) deposition effects on soil organic carbon (C) decomposition remain controversial, while the role of plant species composition in mediating effects of N deposition on soil organic C decomposition and long-term soil C sequestration is virtually unknown. Here we provide evidence from a 5-year grassland field experiment in Minnesota that under elevated atmospheric CO2 concentration (560 ppm), plant species determine whether N deposition inhibits the decomposition of soil organic matter via inter-specific variation in root lignin concentration. Plant species producing lignin-rich litter increased stabilization of soil C older than 5 years, but only in combination with elevated N inputs (4 g m-2 year -1). Our results suggest that N deposition will increase soil C sequestration in those ecosystems where vegetation composition and/or elevated atmospheric CO2 cause high litter lignin inputs to soils.
Copyright 2008 Elsevier B.V., All rights reserved.
- Carbon isotopes
- Elevated CO
- Grassland species
- Nitrogen isotopes
- Root litter
- Soil carbon sequestration
- Soil organic matter decomposition