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27 results found
Nitrogen (N) deposition and its impact on terrestrial and aquatic ecosystems is a concern facing federal land managers at the Lye Brook Wilderness in Vermont and other protected areas throughout the northeastern United States. In this study, we compared N production in soils with N concentrations…
Author(s): John L. Campbell, Christopher Eagar, William H. McDowell, James W. Hornbeck
Keywords: nitrification, nitrogen, nitrogen mineralization, soil water, stream chemistry, wilderness area
Source: Water, Air, and Soil Pollution. 122: 63-75.
Year: 2000
Long- and short-term effects of urban site factors on net N-mineralization and nitrification rates were investigated in oak stands along an urban-rural land-use transect in the New York City metropolitan area. We used reciprocal transplants of undisturbed soil cores between urban and rural forests…
Author(s): Richard V. Pouyat
Keywords: N-mineralization, nitrification, earthworms, exotic species, forests, buried bags, soil organic matter, urban
Source: Urban Ecosystems. 5: 159-178.
Year: 2001
Atmospheric nitrogen deposition to forested ecosystems is a concern because of both geochemical and biological consequences for ecosystem integrity. High levels of prolonged N deposition can lead to "N saturation" of the ecosystem. The Bear Brook Watershed in Maine is a long-term, paired forested…
Author(s): Sultana Jefts, Ivan J. Fernandez, Lindwey E. Rustad, D. Bryan Dail
Keywords: nitrogen cycling, nitrogen mineralization, nitrification, N saturation
Source: Forest Ecology and Management. 189: 189-205.
Year: 2004
We examined 813C and 815N in needle (current and 1-year-old) and soil samples collected on two occasions (July and September 1999) from a 15-year-old loblolly pine (Pinus taeda L.) stand in an irrigation and fertilization experiment to investigate whether these treatments leave specific isotope…
Author(s): Woo-Jung Choi, Scott X. Chang, H. Lee Allen, Daniel L. Kelting, Hee-Myong Ro
Keywords: 13C/12C, 15N/14N, carbon isotope discrimination, nitrification, water use efficiency, Pinus taeda
Source: Forest Ecology and Management 213: 90-101
Year: 2005
Describes factors causing cation export in leachate in low base saturated forested sand soils. Reports the effects of varying acid precipitation and litter-humus treatments on ion movement and interaction.
Author(s): A. Ray Harris, Douglas M. Stone
Keywords: ANC, acid precipitation, nitrification, cation movement
Source: Research Paper NC-305. St. Paul, MN: U.S. Dept. of Agriculture, Forest Service, North Central Forest Experiment Station
Year: 1992
A stand-replacement prescribed fire in an over-mature lodgepole pine (Pinus contorta Dougl. ex Loud.)-subalpine fir (Abies lasiocarpa (Hook.) Nutt.) stand (snag area) and in a mature lodgepole pine thicket (thicket area) resulted in lower plant diversity within the first year…
Author(s): Arthur R. Tiedemann, Paul M. Woodard
Keywords: Forest succession, forest floor, understory vegetation, fuels, soil physical properties, wildlife, snags, downed wood, microbial populations, nitrification, nitrogen fixation, small mammals, birds, elk
Source: Gen. Tech. Rep. PNW-GTR-535. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 26 p
Year: 2002
Nitrogen uptake and cycling was examined using a six-week tracer addition of 15N-labeled ammonium in early spring in Waer Branch, a first-order deciduous forest stream in eastern Tennessee. Prior to the 15N addition, standing stocks of N were determined for the major biomass compartments. During…
Author(s): Patrick J. Mullholland, Jennifer L. Tank, Diane M. Sanzone, Wilfred M. Wollheim, Bruce J. Peterson, Jackson R. Webster, Judy L. Meyer
Keywords: ammonium uptake length, 15N, gross primary production, nitrate uptake length, nitrification, nitrogen cycling, respiration, stable isotope, stream ecosystem, tracer addition
Source: Ecological Monographs. 70(3). 2000. p. 471-493
Year: 2000
This study quantified relationships of understory vascular plant species composition and richness along environmental gradients over a broad spatial scale in second-growth oak forests in eastern North America. Species frequencies were recorded in 108 25 x 25 m plots in four study sites extending…
Author(s): Todd F. Hutchinson, Ralph E.J. Boerner, Louis R. Iverson, Steve Sutherland, Elaine Kennedy Sutherland
Keywords: gradient analysis, moisture index, nitrification, nitrogen mineralization, species richness, understory
Source: Plant Ecology. 144: 177-189.
Year: 1999
Nitrification, the chemoautotrophic process by which NH4-N is converted to NO,-N, is an integral biogeochemical transformation in stream ecosystems. Previous research has shown that experimental addition of dissolved organic C inhibits rates of nitrification, and that NH4
Author(s): Olyssa S. Starry, H. Maurice Valett
Keywords: nitrification
Source: J. N. Am. Benthol. Soc., Vol. 24(4): 753-768
Year: 2005
Virtually complete nitrification of the available ammonium in soil and nitrification activity in the forest floor are important factors predisposing forests in the San Bernardino Mountains of southern California to nitrogen (N) saturation. As a result, inorganic N in the soil solution is dominated…
Author(s): Mark E. Fenn, Mark A. Poth
Keywords: Nitrogen saturation, California, western forests, mixed conifer forests, nitrate, nitrification, nitrogen mineralization, trace gas emissions, nitric oxide, nitrogen excess, nitrogen deposition, soil solution
Source: The Scientific World 1:1-7
Year: 2001