the process by which nutrients move from the soil to plants, animals and back to the soil again. These nutrients are then used by the plant and thus the cycle continues.

Any solution where there are more hydrogen ions present than hydroxide ions, such a solution will have a pH less than 7.

Refers to cations having an acid effect i.e. hydrogen (the most common) and aluminium, ammonium and to a lesser extent some other metal trace elements.

Any soil with a pH less than 7.

A reference to the level of acidity within a chemical environment. When pH greater than 7, the environment is alkaline. When pH less than 7 it is acid.

Microscopic organisms lacking chlorophyll. They obtain their energy from organic matter.

Cations with an alkaline rather than acid effect i.e. calcium, magnesium, potassium and sodium.

A general reference to the living animal and microbial life within the soil.

The living organisms found in a particular area i.e. soil biomass.

The ability of soil to either resist changes in pH, or changes in the concentration of nutrients in soil solution.