Soil solution chemistry and element budgets of three Scots pine ecosystems along a deposition gradient in north-eastern Germany

Since 1993 we are studying three Scots pine ecosystems along a deposition gradient in north-eastern Germany (formerly GDR). Dramatic reductions of pollutant emissions are reported for the period since 1989/90. S-deposition is high at the sites Roesa and Taura (25 kg S ha(-1)yr(-1)) compared to Neuglobsow. Inputs of basic cations, especially Ca, by alkaline dust immissions decrease in the order Roesa > Taura > Neuglobsow solution data show high concentrations of Ca and SO4 at Roesa decreasing drastically along the deposition gradient. The elevated pH values reflect the impact of alkaline dust deposition particularly in the organic surface layer at Roesa. The site Taura received less base cation deposition and is marked by the lowest pH values throughout the soil profile combined with increased Al concentrations in the solution of the mineral soil. Thus, the composition of the soil solutions clearly reflects the different deposition regimes of the past. The element budgets show that large amounts of base cations, sulfur, and, at Taura, also aluminum are actually released from the soils that were previously stored.