pH-Änderungen der Böden im Bereich des Forstamtes Rothenbuch seit 1982

In the forest district of Rothenbuch with an area of about 6100 ha, 88 observation points have been installed, where pH-measurements were carried out since 1982. Statistical analysis of the data shows that about 40 to 50% of the variance of pH can be explained by known influential factors. The pH_KCl in 15-17 cm depth is more strongly affected by the geological parent material, whereas pH_H2O (0-2 cm), pH_H2O (15-17 cm) and pH_KCl (0-2 cm) show a more marked influence of stand structure, ground vegetation and liming. In unlimed pure hardwood stands, pH_H2O in the uppermost mineral soil is influenced by the microbiological milieu, which depends on regional climatic conditions and the interior climate of the stand. During the observation period, a clear pH-decrease as well as a clear pH-increase could be noted at individual measuring points. The pH-shifting depends on the initial pH-value. Observation points with rather high resp. rather low initial pH-values show a marked pH-decrease resp. pH-increase. In the range around pH 4.0, on the average only small pH-fluctuations occur. Although there might be a trend of acidification caused by atmospheric deposition, this cannot be proven by the data of this study. This is due to the fact, that there are many influences affecting the measured pH-value and that soils derived from sandstone are a priori rather acidic.