What is soil?

  • (noun): Material in the top layer of the surface of the earth in which plants can grow (especially with reference to its quality or use).
    Example: "Good agricultural soil"
    Synonyms: land, ground
    See also — Additional definitions below


Soil is a natural body consisting of layers (soil horizons) that are primarily composed of minerals which differ from their parent materials in their texture, structure, consistency, colour, chemical, biological and other characteristics. It is the unconsolidated or loose covering of fine rock particles that covers the surface of the earth. Soil is the end product of the influence of the climate (temperature, precipitation), relief (slope), organisms (flora and fauna), parent materials (original minerals), and time. In engineering, soil is referred to as regolith, or loose rock material: this is the 'drift deposit' lying on top of the 'solid geology'. However, in horticulture, the term 'soil' is defined as the humic layer of topsoil, or the depth of regolith containing organic material that influences and has been influenced by plant roots and may range in depth from centimetres to many metres. Expressions such as lunar soil or Martian soil are commonly used for extraterrestrial regolith, even though there is no known biological component.

Read more about Soil.

Some articles on soil:

Hans Jenny (pedologist)
... Hans Jenny (7 February 1899 – 9 January 1992) was a soil scientist and expert on pedology (the study of soil in its natural environment), particularly the processes of soil formation ...
Cone Penetration Test
... used to determine the geotechnical engineering properties of soils and delineating soil stratigraphy ... It was initially developed in the 1950s at the Dutch Laboratory for Soil Mechanics in Delft to investigate soft soils ... Today, the CPT is one of the most used and accepted in soil methods for soil investigation worldwide ...
FAO Soil Classification
... a supra-national classification, also called World Soil Classification, which offers useful generalizations about soils pedogenesis in relation to the ... It was first published in form of the UNESCO Soil Map of the World (1974) (scale 1 5 M.) ... Originally developed as a legend to the Soil Map of the World, the classification was applied by United Nations sponsored projects ...
Ecological Facilitation - Mechanisms - Refuge From Physical Stress
... increased the fitness of marsh elder (Iva) shrubs in lower elevations, where soil salinity was higher ... The rush shaded the soil, which decreased evapotranspiration, and in turn decreased soil salinity ... However, at higher elevations where soil salinity was lower, marsh elder fitness was decreased in the presence of the rush, due to increased ...
Soil - Reclamation
... Soils which contain high levels of particular clays, such as smectites, are often very fertile ... tropical areas, however, struggle to retain organic matter in the soils they work ... with adding bentonite, one of the smectite family of clays, to the soil ...

More definitions of "soil":

  • (verb): Make soiled, filthy, or dirty.
    Example: "Don't soil your clothes when you play outside!"
    Synonyms: dirty, begrime, grime, colly, bemire
  • (noun): The geographical area under the jurisdiction of a sovereign state.
    Example: "American troops were stationed on Japanese soil"
    Synonyms: territory
  • (noun): The part of the earth's surface consisting of humus and disintegrated rock.
    Synonyms: dirt

Famous quotes containing the word soil:

    Our own country furnishes antiquities as ancient and durable, and as useful, as any; rocks at least as well covered with lichens, and a soil which, if it is virgin, is but virgin mould, the very dust of nature. What if we cannot read Rome or Greece, Etruria or Carthage, or Egypt or Babylon, on these; are our cliffs bare?
    Henry David Thoreau (1817–1862)

    A man’s destination is not his destiny,
    Every country is home to one man
    And exile to another. Where a man dies bravely
    At one with his destiny, that soil is his.
    —T.S. (Thomas Stearns)

    An underground grower, blind and a common brown;
    Got a misshapen look, it’s nudged where it could;
    Simple as soil yet crowded as earth with all.
    Richard Wilbur (b. 1921)