Journal of Conference Abstracts

Integrated Assessment of Soil Chemical Status in Switzerland. 1. Integration of Existing Models and Derivation of Regionalised Input from Available
Sources of Information

Mattius Alveteg¹ (Mattias.Alveteg@chemeng.lth.se), D. Kurz² (GeoSci@aol.com)
& H. Sverdrup¹ (Harald.Sverdrup@chemeng.lth.se)

¹ Department of Chemical Engineering II, Lund, Sweden.

² EKG Geo-Science, Bern, Switzerland.

A regional soil acidification model was developed by integration and adaptation of existing models. The regional model consists of the dynamic multi-layer soil chemistry model SAFE, its steady-state version InitSAFE, the atmospheric deposition and nutrient uptake reconstruction model MakeDEP, and a routine with empirical relations concerning depth-dependent parameters. The empirical relations used were essentially the same as those applied earlier in regional applications of the PROFILE model for calculation of critical loads. The SAFE model calculates the development of base saturation, pH, base cation concentration, etc. The InitSAFE model is used to calculate initial pH and concentrations of base cations, assuming steady-state, or close to steady-state at the beginning of the simulation period. Thus, the simulation should be started before acidification begins. The MakeDEP model was adapted to the conditions in central Europe, favoring small scale harvesting, rather than large clearcuts, and introducing historical removal of leaves and needles by farmers. The regional model was built in a modular fashion to facilitate validation, refinement, and replacement of the different submodules. A scheme for the extraction of input to the regional model from available information of different geographical detail was also developed. Basic data sources considered were

(1) National surveys such as the National Forest Inventory, covering site specific information

(2) available point measurements of parameter values

(3) Literature sources.

All requested parameters were, however, not generally available on a regional scale with sufficient resolution. Input required for the model calculations was therefore derived from the available data sources by means of transfer algorithms including spatial interpolation. Interpolation was done by mutually allocating parameter values and sites considered to conventionally mapped entities such as geological units, soil type and other kinds of geographical information. The exercise resulted in a data base of the requested 68 site specific parameter values covering climatic, deposition and land use parameters, as well as stand characteristics and soil properties.