Soil chemical response to drastic reductions in deposition and its effects on the element budgets of three Scots pine ecosystems

Abstract

During the last 15–20 years the environmental effects of acidic deposition, in particular soil acidification, were studied with different research approaches, ranging from the evaluation of element budgets of whole watersheds to experiments with soil samples in the laboratory, both with and without manipulation (Matzner, 1989; Marschner, 1990; Johnson and Lindberg, 1992; Schaaf, 1992; Beier et al., 1993; Koopmans et al., 1995; Bredemeier et al., 1995; Matzner and Murach, 1995; Moldan et al., 1995; Visser and van Breemen, 1995). In our study, the experimental sites are located along a gradient of atmospheric pollutant deposition, especially with respect to sulfur and alkaline dust. Additionally, the present soil chemical properties of the experimental sites reflect different periods of pollutant deposition with corresponding soil chemical properties of forest ecosytems in Western Europe and thus, can be regarded as the result of a temporal gradient. This gradient ranges from the early 1970s, influenced by high deposition loads of sulfur and dust (site ‘Rösa’) to the early 1980s where the soil chemistry was affected by less alkaline dust but still high sulfur immissions (site ‘Taura’). Since presently the three sites are characterized by relatively low deposition loads, the project can be seen as a ‘roof experiment without roof. Therefore, we are able to study simultaneously the development of the soil chemistry of three soils representing different situations of deposition loads.