APPLICATION OF THE MODEL NUCSAM TO THE SOLLING SPRUCE SITE

The NUtrient Cycling and Soil Acidification Model (NUCSAM) was applied to a spruce site at Selling, Germany, within the scope of a workshop on comparison of forest soil atmosphere models. Simulated trends and d ynamics in the concentrations of SO4, Al and base cations and in pH be tween 1970 and 1990 compared favourably with time series of measured d ata during that period. Dynamics and concentrations of NO3 in the subs oil were overestimated. Simulation results for the period 1990-2090 fo r two deposition scenarios showed ongoing acidification (pH decrease) of the soil at the present acid load and a rapid response of soil solu tion chemistry to reduced acid input, but there was a long time delay before favourable Al/Ca ratios were reached.