soil

soil

(soyl),

Dirt.

Farlex Partner Medical Dictionary © Farlex 2012

soil

the uppermost layer of the earth's crust that supports the majority of terrestrial plant life together with many animals and microorganisms. Soil derives from the erosion of the rock strata and contains minerals and variable amounts of organic material derived from organisms which live or have lived upon it. Soils are affected by climate, living organisms, parent rock, relief, groundwater and age, and usually contain various ‘horizons’, the succession of which is called the ‘soil profile’. MULL soils tend to be alkaline and ‘Mor’ soils acid. Soils may be heavy clay, loam (sand and clay), peaty (large amounts of dead plant material), chalky light or sandy

Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005