Nitrogen saturation and soil N availability in A high-elevation spruce and FIR forest

• Published in: Water, air, and soil pollution Vol. 120; no. 3-4; pp. 295 - 313
• Main Author: GARTEN, C. T
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01.06.2000; Springer Nature B.V
• Subjects: Abies fraseri; AVAILABILITY; Earth sciences; Earth, ocean, space; Elevation; Environmental monitoring; ENVIRONMENTAL SCIENCES; Exact sciences and technology; Field study; FIRS; FORESTS; Geochemistry; LEACHING; MINERALIZATION; MOUNTAINS; National parks; NITRATES; NITRIFICATION; NITROGEN; NORTH CAROLINA; ORGANIC MATTER; Organic soils; PARTICULATES; Picea rubens; SATURATION; Soil and rock geochemistry; Soil organic matter; SOILS; SPRUCES; Surficial geology; TENNESSEE; USA, Great Smoky Mts. Natl. Park; North Carolina; Appalachians; United States; Great Smoky Mountains; Tennessee; USA, Great Smoky Mountains Natl. Park; particulate matters; gymnosperms; nitrogen; Plantae; topography; vegetation; leaching; nitrates; North America; mineralization; Pinaceae; Abies; organic materials; Coniferales; Spermatophyta; statistical analysis; soils; Picea; national parks
• ISSN: 0049-6979; 1573-2932
• DOI: 10.1023/A:1005270012802

A field study was conducted during the summer of 1995 to gain abetter understanding of the causes of nitrate (NO^sub 3^-N)leaching and ongoing changes in soil nitrogen (N) availabilityin high-elevation (1524-2000 m) spruce (Picea rubens) andfir (Abies fraseri) forests of the Great Smoky MountainsNational Park, Tennessee and North Carolina, U.S.A. Indicatorsof soil N availability (total soil N concentrations,extractable NH^sub 4^-N, extractable NO^sub 3^-N, and C/N ratios)were measured in Oa and A horizons at 33 study plots. Dynamicmeasures included potential net soil N mineralization determinedin 12-week aerobic laboratory incubations at 22 °C.Potential net nitrification in the A horizon was correlated (r =+0.83, P < 0.001) with total soil N concentrations. Mostmeasures of soil N availability did not exhibit significanttrends with elevation, but there were topographic differences.Potential net soil N mineralization and net nitrification in theA horizon were higher in coves than on ridges. Relative amountsof particulate and organomineral soil organic matter influencedpotential net N mineralization and nitrification in the Ahorizon. Calculations indicate that soil N availability andNO^sub 3^-N leaching in high-elevation spruce and fir forests ofthe Great Smoky Mountains National Park will increase inresponse to regional warming.[PUBLICATION ABSTRACT]