Acidification and Nitrogen Eutrophication of Austrian Forest Soils

Abstract

We evaluated the effect of acidic deposition and nitrogen on Austrian forests soils. Until thirty years ago air pollution had led to soil acidification, and concerns on the future productivity of forests were raised. Elevated rates of nitrogen deposition were believed to cause nitrate leaching and imbalanced forest nutrition. We used data from a soil monitoring network to evaluate the trends and current status of the pH and the C : N ratio of Austrian forest soils. Deposition measurements and nitrogen contents of Norway spruce needles and mosses were used to assess the nitrogen supply. The pH values of soils have increased because of decreasing proton depositions caused by reduction of emissions. The C : N ratio of Austrian forest soils is widening. Despite high nitrogen deposition rates the increase in forest stand density and productivity has increased the nitrogen demand. The Austrian Bioindicator Grid shows that forest ecosystems are still deficient in nitrogen. Soils retain nitrogen efficiently, and nitrate leaching into the groundwater is presently not a large-scale problem. The decline of soil acidity and the deposition of nitrogen together with climate change effects will further increase the productivity of the forests until a limiting factor such as water scarcity becomes effective.

Forest floor vegetation response to nitrogen deposition in Europe

“…This could be expected as most oligotrophic forest species prefer acidic soils (Diekmann, ) and reach their optimum under dry conditions (Cornwell & Grubb, ). Owing to this dependency, we cannot judge how strong the role of soil recovery from acidification, which has occurred in many parts of Europe in recent decades (Kirk et al ., ; Jandl et al ., ; Akselsson et al ., ), was in increasing the eutrophication effect on acidophytic plant species. Species that tolerate dry conditions (Ellenberg value < 4) are seldom common species in European forests.…”

Compositional changes in thermophilous oak forests in Poland over time: do they correspond to European trends?

“…However, the rise in soil pH, as a result of reduced SO 2 pollution in the 21st century, was recently recorded in the soils of Austrian forest communities (Jandl et al. ) and in the soils of England and Wales (Kirk et al. ).…”

Nitrogen deposition and its impact on forest ecosystems in the Czech Republic - change in soil chemistry and ground vegetation

“…The effect of N input on the forest ecosystem is complex and disputable -from fertilisation (Solberg et al 2004, Jandl et al 2012 to acidification (Zapletal 1998, 2001, 2006, Augustin et al 2005, Vícha et al 2012. Also its potential to cause a loss of diversity in understory vegetation in forest stands is complex (Okland 1995, Wamelink et al 2008, Kreutzer et al 2009, Buriánek et al 2013.…”

“…In connection with higher N input to the forest stands, a positive fertilization effect on growth is likely. For instance, Austrian forest soil is still deficient in N and stands respond positively to higher N deposition (Jandl et al 2012). The positive effect of N on forest growth is mentioned by, among others, Solberg et al (2004Solberg et al ( , 2009).…”