Skip to Main Content
A Cross-Site Comparison of Factors Influencing Soil Nitrification Rates in Northeastern USA Forested WatershedsAuthor(s): Donald S. Ross; Beverley C. Wemple; Austin E. Jamison; Guinevere Fredriksen; James B. Shanley; Gregory B. Lawrence; Scott W. Bailey; John L. Campbell
Source: Ecosystems. 12(1): 158-178.
Publication Series: Scientific Journal (JRNL)
Station: Northern Research Station
View PDF (686.07 KB)
DescriptionElevated 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.
- Check the Northern Research Station web site to request a printed copy of this publication.
- Our on-line publications are scanned and captured using Adobe Acrobat.
- During the capture process some typographical errors may occur.
- Please contact Sharon Hobrla, email@example.com if you notice any errors which make this publication unusable.
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationRoss, Donald S.; Wemple, Beverley C.; Jamison, Austin E.; Fredriksen, Guinevere; Shanley, James B.; Lawrence, Gregory B.; Bailey, Scott W.; Campbell, John L. 2009. A Cross-Site Comparison of Factors Influencing Soil Nitrification Rates in Northeastern USA Forested Watersheds. Ecosystems. 12(1): 158-178.
Keywordsacidic deposition, ammonification, nitrogen transformations, conifers, Acer saccharum, Picea rubens, soil calcium
- Initial tree regeneration response to natural-disturbance-based silviculture in second-growth northern hardwood forests
- Effect of Sugar Maple Root Exudate on Seedlings of Northern Conifer Species
- Comparative growth trends of five northern hardwood and montane tree species reveal divergent trajectories and response to climate
XML: View XML