Increasing levels of nitrogen deposition associated with industry and agriculture can drive soils toward a toxic level of acidification, reducing plant growth and polluting surface waters, according to a new study published online in Nature Geoscience.
The study, conducted in the Tatra Mountains of Slovakia by the University of Colorado, University of Montana, Slovak Academy of Sciences, and the U.S. Geological Survey, shows what can happen when nitrogen deposition in any part of the world increases to certain levels levels similar to those projected to occur in parts of Europe by 2050, according to some global change models.
On the basis of these results, the authors warn that the high levels of nitrogen deposited in Europe and North America over the past half century already may have left many soils susceptible to this new stage of acidification. The results of this further acidification, wrote the authors, are highly reduced soil fertility and leaching of acids and toxic metals into surface waters.
A long history of human-influenced nitrogen deposition has left soils in the Western Tatra Mountains of Slovakia highly acidic. The study reveals that the increased nitrogen load in the region triggers the release of soluble iron into alpine grassland soils. This iron release is indicative of extreme soil acidification, comparable to conditions seen in soils exposed to acid mine drainage.
"Recovery from such extreme chemical change could only occur in geologic time, which is why soil is considered a non-renewable resource," said USGS scientist Jill Baron, who helped analyze and interpret the study results.
In addition to this research, Dr. Baron has investigated the impacts of nitrogen deposition in Rocky Mountain National Park for 26 years. "The Rocky Mountains and the Tatra Mountains represent the two ends of the atmospheric deposition effects trajectory," Dr. Baron said. "The effects of nitrogen deposition in Rocky Mountain Natio
|Contact: Jill Baron|
United States Geological Survey