Columbia subject headings:
Acid rain--Environmental aspects.
Acid soils.
Nitrogen cycle.
Soil acidity.
Soil management.
Sulfur cycle.
Harvard subject headings:
Acid rain--Environmental aspects
Acid soils.
Nitrogen cycle.
Soil acidity.
Soil management.
Sulfur cycle.
Princeton subject headings:
Acid rain--Environmental aspects.
Acid soils.
Nitrogen cycle.
Soil acidity.
Soil management.
Sulfur cycle.