Increased anthropogenic deposition of nitrogen (N) and land-use changes associated with planted forests have important implications for sustainable forest management and associated water quality. The purpose of the research for this dissertation was to explore how N deposition will affect the long-term health, productivity, and carbon (C) and N sequestration of conifer and hardwood forest types by examining the mechanisms controlling N cycling and NO3-N production in two watersheds with contrasting vegetation at the Fernow Experimental Forest (FEF), West Virginia. I utilized watershed C and N budgets to account for differences in stream export of NO3-N from streams draining adjacent watersheds containing (i) planted Norway spruce (Picea abies) and (ii) native Appalachian hardwoods. I also investigated spatial and temporal patterns of dissolved C and N across both watersheds and identified key soil properties associated with NO3-N in soil solution and streamwater. In a third study, I performed a soil inoculation and incubation experiment, which utilized soil from both watersheds, mixed in ratios in order to create a gradient of soil chemical and biotic characteristics. Important differences in biogeochemical cycling of C and N were documented in the watersheds after nearly 40 years of influence by contrasting vegetation. Total C and N pools were 28% and 35% lower in the spruce watershed than the hardwood watershed, respectively. Results also identify vegetation-mediated differences in soil characteristics, with lower soil pH and base cations, and higher extractable aluminum and C:N ratios measured in the spruce soil as compared to the native hardwood soil. Establishment of a spruce monoculture at the FEF significantly altered N cycling, depleted N stores, increased soil acidity, and altered organic matter dynamics, thus leading to low net nitrification rates. Carbon and N properties and processes in the soil profile should be taken into consideration in forests managed for ecosystem services including C sequestration and improvement or maintenance of water quality through alleviation of N inputs into aquatic ecosystems. / Ph. D.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/26860 |
| Date | 06 May 2010 |
| Creators | Kelly, Charlene Nicole |
| Contributors | Forestry, Schoenholtz, Stephen H., Zipper, Carl E., Adams, Mary Beth, Berry, Duane F., Webster, Jackson R., Burger, James A. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | Kelly_CN_D_2010.pdf |
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