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RECORD NUMBER: 574 OF 2348

OLS Field Name OLS Field Data
Main Title Experimental Inducement of Nitrogen Saturation at the Watershed Scale.
Author Kahl, J. S. ; Norton, S. A. ; Fernandez, I. J. ; Nadelhoffer, K. J. ; Driscoll, C. T. ;
CORP Author Maine Univ. at Orono. ;Marine Biological Lab., Woods Hole, MA. Ecosystems Center. ;State Univ. of New York Coll. of Environmental Science and Forestry, Syracuse. Dept. of Civil Engineering.;New Hampshire Univ., Durham. Complex Systems Research Center.;Corvallis Environmental Research Lab., OR.
Publisher c1993
Year Published 1993
Report Number EPA/600/J-93/254;
Stock Number PB93-212603
Additional Subjects Watersheds ; Land pollution ; Water pollution ; Acidification ; Forest land ; Nitrogen cycle ; Air pollution ; Ecosystems ; Water quality ; Nitrogen oxides ; Air land interactions ; Deposition ; Trees(Botany) ; Experimental design ; Nutrients ; Reprints ; Nitrogen saturation
Holdings
Library Call Number Additional Info Location Last
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Status
NTIS  PB93-212603 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. NTIS 11/22/1993
Collation 6p
Abstract
Atmospheric nitrogen deposition to forested ecosystems in excess of vegetative demand may lead to a condition of terrestrial 'nitrogen saturation'. The subsequent increases in N export to surface waters are symptomatic of fundamental changes in terrestrial nutrient processing. The authors have experimentally induced incipient N saturation in a paired-catchment experiment at the Bear Brook Watershed in Maine (BBWM). Using modest loading rates of N compared to typical forest fertilization rates or the N pool in forest soils, the experiment has resulted in large increases in NO3(-) concentrations in streams. Nitrate flux from the treated catchment has increased from 200 to more than 500 equiv/ha/yr. Seasonal patterns in stream NO3(-) concentrations have been fundamentally altered by the treatment, with NO3(-) loss now occurring nearly all year from the experimental watershed. These results suggest that N saturation, soil acidification, and altered N cycling in forested watersheds may be induced at lower rates of N deposition than previously believed.