Calcareous substances contain mostly calcium carbonate
or other calcium salts. A soil that contains more than 2%
calcium carbonate (often dong with magnesium
carbonate) and produces vigorous effervescence when
treated with 0.1N hydrochloric acid, is termed
calcareous soil. Calcareous soil is classified depending
on the calcium carbonate content as slightly calcareous,
moderately calcareous and highly calcareous.
Brown calcareous soils are well-drained soils with a
medium to heavy texture. They are slightly acidic in the
surface layers and calcareous underneath and are
developed over limestone or calcareous sandstone.
