Reinds,G.J., Posch,M., de Vries,W., Slootweg,J. and Hettelingh,j.-P.(2008): Critical loads of sulphur and nitrogen for terrestrial ecosystems in Europe and Northern Asia using different soil chemical criteria. Water Air Soil Pollut., 193, 269-287.

『異なる土壌化学基準を用いたヨーロッパと北部アジアにおける陸域生態系に対するイオウと窒素の臨界負荷量』

『Abstract
　A critical load data base was developed for Europe and Northern Asia using the latest data bases on soils, vegetation, climate and forest growth. Critical loads for acidity and nutrient nitrogen for terrestrial ecosystems were computed with the Simple Mass Balance model. The resulting critical loads are in accordance with critical loads from previous global empirical studies, but have a much higher spatial resolution. Critical loads of acidity are sensitive to both the chemical criterion and the critical limit chosen. Therefore a sensitivity analysis of critical loads was performed by employing different chemical criteria. A critical limit based on an acid neutralizing capacity (ANC) of zero resulted in critical loads that protect ecosystems against toxic concentrations of aluminium and unfavourable Al/Bc ratios, suggesting that ANC could be an alternative to the commonly used Al/Bc ratio. Critical loads of nutrient nitrogen are sensitive to the specified critical nitrate concentrations, especially in areas with a high precipitation surplus. If limits of 3-6 mg N l-1 are used for Western Europe instead of the widely used 0.2 mg N l-1, critical loads double on average. In low precipitation areas, the increase is less than 50％. The strong dependence on precipitation surplus is a consequence of the simple modelling approach. Future models should explore other nitrogen parameters (such as nitrogen availability) instead of leaching as the factor influencing vegetation changes in terrestrial ecosystems.

Keywords: Critical loads; Acidification; Eurasia; Soil and land cover; Uncertainties; Equivalent criteria』

1. Introduction
2. Methods
　2.1. The critical load model
　2.2. Chemical criteria
　2.3. Geographical data bases
　2.4. Meteorology and hydrology
　2.5. Base cation deposition and weathering
　2.6. Nutrient uptake, nitrogen immobilization and denitrification
　2.7. Al-H relationship and organic acids
3. Results
　3.1. Input data
　3.2. Critical loads of acidity (sulphur)
　3.3. Critical loads of N
　3.4. Sensitivity of critical loads
　　3.4.1. sensitivity to the selection of receptors
　　3.4.2. Sensitivity to criteria
　　　Critical load of acidity
　　　Critical load for eutrophication
4. Discussion and conclusions
Acknowledgement
Open access
Appendix
　Simple mass balance (SMB) models
　Critical load of nutrient nitrogen
　Critical loads of acidity
　Derivation of the critical ANC leaching
References

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