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Harvard Forest Symposium Abstract 2010

  • Title: The Effects of Soil Warming and Nitrogen Deposition on Soil Water Quality
  • Primary Author: Brian Godbois (University of New Hampshire - Main Campus)
  • Additional Authors: Alix Contosta (University of New Hampshire - Main Campus); Serita Frey (University of New Hampshire - Main Campus)
  • Abstract:

    Soil warming caused by global climate change as well as atmospheric nitrogen (N) deposition, caused by emissions from industry, transportation, and power plants, are two environmental disturbances with global significance. The objective of this research project was to determine the effects of soil warming and N deposition on soil water quality. Several previous studies on the individual impacts of N deposition or climate warming on soils have been published, but never a study on the simultaneous effect of both treatments on soil water quality. For this project soil water samples were collected monthly from the Soil Warming × Nitrogen Addition experiment located at the Harvard Forest Long Term Ecological Research site in Petersham, Massachusetts. The Folin-Ciocalteau method was used to analyze the concentration of phenol carbon (C), a measure of soil water quality. A non-parametric ANOVA was applied to examine differences in phenol C among treatments for each sampling date. The concentration of soluble phenolic C, a fraction of the dissolved organic matter (DOM) in soil water, was not significantly affected by simultaneous warming and nitrogen fertilization treatments. There was however, a strong seasonal pattern of average concentrations of soluble phenolic C across all treatments. Previous studies have shown that N fertilization can inhibit the production of oxidative enzymes which allow microorganisms to utilize phenolic C, resulting in an accumulation of recalcitrant DOM within the soil water pool. However, in this study, it appears that microbial utilization of phenol C was not impacted by either warming or N additions.

  • Research Category: Soil Carbon and Nitrogen Dynamics