The Fernow Watershed Acidification Study: ecosystem acidification, nitrogen saturation and base cation leaching
- Download PDF (307117)
- This publication is available only online.
Water, Air, and Soil Pollution: Focus. 7: 267-273.
In 1989, a watershed acidification experiment was begun on the Fernow Experimental Forest in West Virginia, USA. Ammonium sulfate fertilizer (35.5 kg N ha−1 yr−1 and 40.5 kg S ha−1 yr−1) was applied to a forested watershed (WS3) that supported a 20-year-old stand of eastern deciduous hardwoods. Additions of N and S are approximately twice the ambient deposition of nitrogen and sulfur in the adjacent mature forested watershed (WS4), that serves as the reference watershed for this study. Acidification of stream water and soil solution was documented, although the response was delayed, and acidification processes appeared to be driven by nitrate rather than sulfate. As a result of the acidification treatment, nitrate solution concentrations increased below all soil layers, whereas sulfate was retained by all soil layers after only a few years of the fertilization treatments, perhaps due to adsorption induced from decreasing sulfate deposition. Based on soil solution monitoring, depletion of calcium and magnesium was observed, first from the upper soil horizons and later from the lower soil horizons. Increased base cation concentrations in stream water also were documented and linked closely with high solution levels of nitrate. Significant changes in soil chemical properties were not detected after 12 years of treatment, however.
Keywordsacidic deposition base cation leaching forest soils nitrogen saturation soil solution chemistry
Adams, Mary Beth; Kochenderfer, James N.; Edwards, Pamela J. 2007. The Fernow Watershed Acidification Study: ecosystem acidification, nitrogen saturation and base cation leaching. Water, Air, and Soil Pollution: Focus. 7: 267-273.