acid A substance containing hydrogen ions which can be neutralized by an
alkali. The
pH of acid is below 7. An
acid soil has a
pH of less than 7. Acidity in a soil may be due to the
leaching out of
cations when
precipitation exceeds
evapotranspiration. The cations are replaced by hydrogen ions. Other factors promoting acidity in a soil include the nature of the vegetation, and thus the
humus, and the acidity of the parent rock. Examples of acid soils are
podzols and
brown earths.
The term ‘acid’ as applied to rocks has an entirely different meaning. See
acid rock.
Комментариев нет:
Отправить комментарий