Bodenversauerung in den Flächen des Interkantonalen Walddauerbeobachtungsprogramms

Abstract

Soil acidification is followed in Swiss forest observation plots differing in soil chemistry. Soil solution samples from suction cups show clearly increasing soil acidification between 1998 and 2011, although the rate has declined in many cases during the last five years. The most rapid decline is currently observed in plots with medium to high base saturation. Nitrogen addition experiments and time series after thinning out forests confirm the important role of nitrogen input and nitrate leaching for the acidification process. It is suggested that the slowdown of acidification since 2003 has several reasons: reaching of the aluminium buffer range in the very acidic plots, decreased nitrate leaching in a series of dry years, reduction of acid deposition.