APPLICATION OF THE MODEL NICCCE TO THE SOLLING SPRUCE SITE

A model for turnover of C and N in coniferous ecosystems has been appl ied to the long-term data set available for the Selling spruce site in Germany. The model (NIICCCE; NItrogen Isotopes and Carbon Cycling in Coniferous Ecosystems) simulates water and heat transport, primary pro duction, and turnover of C and N for coniferous forest on a multi-laye r soil profile. Application of the model to the Selling site involved calibration to the specific soil conditions and tree species present a t this site. Observed amounts of throughfall, pressure heads of soil w ater, and chloride concentrations at various depths were satisfactory reproduced by the model, as well as concentrations and fluxes of C and N in various tree compartments. Leaching of nitrate below the rooting zone, amounting to 18 kmol ha(-1) over a 17-year period, was simulate d well, but some annual and seasonal variations of nitrate concentrati ons could not be reproduced by the model. In particular the large annu al variations in nitrate concentrations observed below the litter laye r were not satisfactory reproduced.