Spatial Variability and Long-Term Trends in Mass Balance of N and S in Central European Forested Catchments

Abstract

Acid deposition linked to SO₂ emissions has provoked a large-scale acidification of soils and waters in Europe. Losses of nutrients caused by soil acidification, enhancement of forest growth by nitrogen deposition, and climatic stress were determinant factors of the large scale spruce decline in central Europe. Beginning in the mid-1970s after the petrol crisis in western Europe, and more recently following the political and economic changes in Eastern Europe, a large reduction in SO₂ emissions and acid deposition has occurred over Europe. Simultaneously, the deposition of nitrogen compounds has remained stable or increased. These changes in S and N deposition have been often reflected by nitrate and sulphate concentrations in runoff. However, internal soil processes may interact in such a way that the trends in deposition may not be seen in the stream clearly (Durka et al. 1994). The relative influence of these processes is difficult to quantify as there has been only few long-term investigations integrating both the stand spatial variability and the role of recharge areas. This chapter focuses on the mean and long-term fate of S and N inputs at the catchment scale and present comparative budgets at the forest stand and whole-catchment scales. The comparison reflects the environmental changes along the west east cross-section through central Europe.