Ecosystems

, Volume 12, Issue 1, pp 158–178

A Cross-Site Comparison of Factors Influencing Soil Nitrification Rates in Northeastern USA Forested Watersheds

  • Donald S. Ross
  • Beverley C. Wemple
  • Austin E. Jamison
  • Guinevere Fredriksen
  • James B. Shanley
  • Gregory B. Lawrence
  • Scott W. Bailey
  • John L. Campbell
Article

DOI: 10.1007/s10021-008-9214-4

Cite this article as:
Ross, D.S., Wemple, B.C., Jamison, A.E. et al. Ecosystems (2009) 12: 158. doi:10.1007/s10021-008-9214-4

Abstract

Elevated N deposition is continuing on many forested landscapes around the world and our understanding of ecosystem response is incomplete. Soil processes, especially nitrification, are critical. Many studies of soil N transformations have focused on identifying relationships within a single watershed but these results are often not transferable. We studied 10 small forested research watersheds in the northeastern USA to determine if there were common factors related to soil ammonification and nitrification. Vegetation varied between mixed northern hardwoods and mixed conifers. Watershed surface soils (Oa or A horizons) were sampled at grid or transect points and analyzed for a suite of chemical characteristics. At each sampling point, vegetation and topographic metrics (field and GIS-based) were also obtained. Results were examined by watershed averages (n = 10), seasonal/watershed averages (n = 28), and individual sampling points (n = 608). Using both linear and tree regression techniques, the proportion of conifer species was the single best predictor of nitrification rates, with lower rates at higher conifer dominance. Similar to other studies, the soil C/N ratio was also a good predictor and was well correlated with conifer dominance. Unlike other studies, the presence of Acer saccharum was not by itself a strong predictor, but was when combined with the presence of Betula alleghaniensis. Topographic metrics (slope, aspect, relative elevation, and the topographic index) were not related to N transformation rates across the watersheds. Although found to be significant in other studies, neither soil pH, Ca nor Al was related to nitrification. Results showed a strong relationship between dominant vegetation, soil C, and soil C/N.

Keywords

acidic depositionammonificationnitrogen transformationsconifersAcer saccharumPicea rubenssoil calcium

Supplementary material

10021_2008_9214_MOESM1_ESM.doc (96 kb)
(DOC 140 kb)

Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • Donald S. Ross
    • 1
  • Beverley C. Wemple
    • 2
  • Austin E. Jamison
    • 3
  • Guinevere Fredriksen
    • 4
  • James B. Shanley
    • 5
  • Gregory B. Lawrence
    • 6
  • Scott W. Bailey
    • 7
  • John L. Campbell
    • 8
  1. 1.Department of Plant and Soil ScienceUniversity of VermontBurlingtonUSA
  2. 2.Geography DepartmentUniversity of VermontBurlingtonUSA
  3. 3.Blue Ridge DivisionChesapeake Wildlife HeritageCharlottesvilleUSA
  4. 4.Ecology & Evolutionary BiologyCornell UniversityIthacaUSA
  5. 5.United States Geological SurveyMontpelierUSA
  6. 6.United States Geological Survey, Water Resources DivisionTroyUSA
  7. 7.United States Forest ServiceHubbard Brook Experimental ForestNorth WoodstockUSA
  8. 8.United States Forest ServiceDurhamUSA