What is soil

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What is soil?

• You have 3 minutes to develop a group consensus
  definition.

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Merriam-Webster Online Dictionary

• Main Entry 3soil, noun1 firm land EARTH2
  a the upper layer of earth that may be dug or
  plowed and in which plants grow b the
  superficial unconsolidated and usually weathered
  part of the mantle of a planet and especially of
  the earth3 COUNTRY, LAND ltour native soilgt4
  the agricultural life or calling5 a medium in
  which something takes hold and develops

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Wikipedia The Free Encyclopedia
http//en.wikipedia.org/wiki/Soil

• Soil is material capable of supporting plant
  life. Soil forms through a variety of soil
  formation processes, and includes weathered rock
  "parent material" combined with dead and living
  organic matter and air.
• Soils are vital to all life on Earth because they
  support the growth of plants, which supply food
  and oxygen and absorb carbon dioxide and
  nitrogen.

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OneLook Dictionary Searchhttp//onelook.com/?wso
illsa

• Quick definitions (soil)
• noun   the part of the earth's surface
  consisting of humus and disintegrated rock
• noun   the geographical area under the
  jurisdiction of a sovereign state (Example
  "American troops were stationed on Japanese
  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")
• noun   the state of being covered with unclean
  things
• verb   make soiled, filthy, or dirty (Example
  "Don't soil your clothes when you play outside!")

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discoveryschool.com

• Whats the difference between soil and dirt? Dirt
  is what you find under your fingernails. Soil is
  what you find under your feet. Think of soil as a
  thin living skin that covers the land. It goes
  down into the ground just a short way. Even the
  most fertile topsoil is only a foot or so deep.
  Soil is more than rock particles. It includes all
  the living things and the materials they make or
  change.

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discoveryschool.com, contd

• There is no soil on Mars or Venus. How come?
  Those planets have plenty of rocks. Mars has
  windstorms that erode rocks into dust. Venus has
  an acid atmosphere that cooks rocks into new
  chemicals. But there's still something missing.
  Without life, there is no soil. Living things
  haven't just made a home in the soil on our
  planet. Life actually made the soil as we know it.

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Definitions (simplified)

• Soil is a dynamic, heterogeneous, three-phase,
  porous media
• Perspective Soil Physics
• Soil is the outer layer of the earths crust
  capable of supporting plant growth (Pearson,
  1967, Principles of Agronomy)
• Perspective Botany, Agronomy, Horticulture, ...
• Soil is unconsolidated, surficial material.
• Perspective Geology, Engineers

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Definitions, Byers, et al., Formation of Soil,
1938

• Soils are natural media for the growth of plants.
  They are mixtures of fragmented and partly or
  wholly weathered rocks and minerals, organic
  matter, water, and air, in greatly varying
  proportions, and have more or less distinct
  layers or horizons developed under the influence
  of climate and living organismsSoils are dynamic
  in character the product of the action of
  climate and living organisms upon the parent
  material, as conditioned by the local relief.
• Yearbook of Agriculture

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Definitions, Simonson, What Soils Are, 1957

• The soil is the link between the rock core of the
  earth and the living things on its surface. It is
  the foothold for the plants we grow.
• The soil mantle of the earth is far from uniform,
  but all soils have some things in common.
• Every soil consists of mineral and organic
  matter, water, and air
• Every soil occupies space ...
• Every soil has a profile
• Yearbook of Agriculture

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Definitions, Hillel, Introduction to Soil
Physics, 1982

• Soil refers to the weathered and fragmented outer
  layer of the earths terrestrial surface.
• The soil is a heterogeneous, polyphasic,
  particulate, disperse, and porous system, in
  which the interfacial area per unit volume can be
  very large. The disperse nature of the soil and
  its consequent interfacial activity give rise to
  such phenomena as adsorption of water and
  chemicals, ion exchange, adhesion, swelling and
  shrinking, dispersion and flocculation, and
  capillarity.

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Definitions, Daubenmire, Plants and Environment,
1974

• Soil any part of the earths crust in which
  plants are anchored the muddy bottoms of ponds,
  porous rock surfaces into which cryptogams send
  their rhiziods, peat, raw gravel deposited by
  glaciers, etc.
• Soil may be defined as the weathered superficial
  layer of the earths crust with which are mingled
  living organisms and products of their decay.
• A Textbook of Autecology, 3rd ed.

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Definitions, Spangler Handy, 1982, Soil
Engineering

• Soils are natural materials which occur in
  infinite variety over the earth and whose
  engineering properties may vary widely from place
  to place within the relatively small confines of
  a single engineering project
• The properties of soils are continuously changing
  as the amount of moisture fluctuates and other
  environmental influences vary and may change
  dramatically under load
• Soil is used as construction material

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Definition, Soil Science Glossary, SSSA

• (i) The unconsolidated mineral or organic
  material on the immediate surface of the earth
  that serves as a natural medium for the growth of
  land plants.

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Definition, Soil Science Glossary, SSSA, contd

• (ii) The unconsolidated mineral or organic matter
  on the surface of the earth that has been
  subjected to and shows effects of genetic and
  environmental factors of climate (including
  water and temperature effects), and macro- and
  microorganisms, conditioned by relief, acting on
  parent material over a period of time. A
  product-soil differs from the material from which
  it is derived in many physical, chemical,
  biological, and morphological properties and
  characteristics.

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Definition, Joffe, 1949, modified by Birkeland,
1999

• Soil is a natural body consisting of layers
  (horizons) of mineral and/or organic constituents
  of variable thicknesses, which differ from the
  parent materials in their morphological,
  physical, chemical, and mineralogical properties
  and their biological characteristics.

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Definition, Soil Taxonomy, 2nd ed.

• Soil is a natural body comprised of solids
  (minerals and organic matter), liquid, and gases
  that occurs on the land surface, occupies space,
  and is characterized by one or both of the
  following horizons, or layers, that are
  distinguishable from the initial material as a
  result of additions, losses, transfers, and
  transformations of energy and matter or the
  ability to support rooted plants in a natural
  environment.

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Definition, Soil Taxonomy, 2nd ed.

• The upper limit of soil is the boundary between
  soil and air, shallow water, live plants, or
  plant materials that have not begun to decompose.
  Areas are not considered to have soil if the
  surface is permanently covered by water too deep
  (typically more than 2.5 meters) for the growth
  of rooted plants.

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Definition, Soil Taxonomy, 2nd ed.

• The lower boundary that separates soil from the
  nonsoil underneath is most difficult to define.
  Soil consists of horizons near the earth's
  surface that, in contrast to the underlying
  parent material, have been altered by the
  interactions of climate, relief, and living
  organisms over time. Commonly, soil grades at its
  lower boundary to hard rock or to earthy
  materials virtually devoid of animals, roots, or
  other marks of biological activity. For purposes
  of classification, the lower boundary of soil is
  arbitrarily set at 200 cm.