Decomposition and Release of ^15N from Fine Roots
Collaborators:	Mark Harmon, Tiffany van Huysen, Hua Chen (OSU)
Funding:	NSF International Programs

Root decomposition and nitrogen (N) dynamics are poorly understood controls of soil organic matter formation, ecosystem N cycling, and ecosystem responses to disturbance and climate change. Previous work indicates that N dynamics of decomposing roots differ from that observed in aboveground litter in Pacific Northwest forests in unexpected ways. Fine roots display net N release in the earliest phases of decomposition, while coarse roots release N at very high C:N (average C:N = 140) relative to “critical” C:N ratios developed for soils.

This project uses decomposition of ¹⁵N labeled roots in the field to examine relationships between mass loss, N release, and the fate of fine-root N in the soil environment. Cooperative studies further seek to understand how climate (e.g, temperature, precipitation) and substrate quality (e.g., initial lignin/N concentration ratio) influence mass loss and N dynamics of 6 species decomposing fine roots in Pacific Northwest, USA, and Taiwan. This research will yield new insights into belowground C and N dynamics of both the temperate and subtropical forests

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