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Modelling long-term cation supply in acidified forest stands.
P Warfvinge1, U Falkengren-Grerup, H Sverdrup
1Department of Chemical Engineering II, Lund Institute of Technology, PO Box 124, S-221 00 Lund, Sweden.
Environmental Pollution (Barking, Essex : 1987)
|January 1, 1993
Summary
Acid deposition caused soil acidification in southern Sweden, decreasing soil base saturation. The Soil Acidification in Forest Ecosystems (SAFE) model revealed weathering and cation exchange buffer acidity, but budget studies alone cannot differentiate their long-term versus short-term effects.
Area of Science:
- Environmental Chemistry
- Forest Ecology
- Soil Science
Background:
- Observed decrease in soil base saturation at three southern Sweden stands between 1949-1984.
- Acid deposition is a significant environmental stressor impacting forest ecosystems.
Purpose of the Study:
- To explain the observed decrease in soil base saturation using a dynamic soil chemistry model.
- To investigate the role of acid deposition in soil acidification.
Main Methods:
- Utilized the Soil Acidification in Forest Ecosystems (SAFE) model.
- Incorporated physical processes (leaching, accumulation) and chemical processes (cation exchange, weathering, nutrient uptake).
- Quantified sources and sinks of base cations in the soil system.
Main Results:
- Acid deposition was identified as the cause of soil acidification.
- Weathering, deposition, and depletion of exchangeable base cations supplied similar amounts of cations to the soil solution.
- Distinguished between long-term resistance (weathering) and short-term buffering (cation exchange).
Conclusions:
- Dynamic soil chemistry modeling is crucial for understanding complex soil acidification processes.
- Budget studies alone are insufficient to differentiate buffering mechanisms.
- Forest soil acidification is a complex process influenced by multiple chemical and physical factors.