INTEGRATED ASSESSMENT OF SOIL CHEMICAL STATUS - 1 - INTEGRATION OF EXISTING MODELS AND DERIVATION OF A REGIONAL DATABASE FOR SWITZERLAND

A regional soil acidification model was developed by integration and a daptation of existing models. The regional model consists of the dynam ic multi-layer soil chemistry model SAFE, its steady-state version INI TSAFE, the atmospheric deposition and nutrient uptake reconstruction m odel MAKEDEP, and a routine with empirical relations concerning depth- dependent parameters. A scheme for the extraction of input to the regi onal model from available information of different geographical detail also was developed. Basic data sources considered were: 1) national s urveys such as the National Forest Inventory, covering site specific i nformation, 2) available point measurements of parameter values, and 3 ) literature sources. Not all parameters were available on a regional scale with sufficient resolution. Input required for the model calcula tions therefore was derived from the available data sources by means o f transfer algorithms including spatial interpolation. Interpolation w as done allocating parameter values determined at reference sites to c onventionally mapped entities such as geological units, soil type, and other kinds of geographical information. The exercise resulted in a d ata base of the required 68 site-specific parameter values covering cl imatic, deposition and land use parameters, as well as stand character istics and soil properties.