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Glossary on Soil Science (3)  (the end)
作者:eclin  文章来源:本站原创  点击数  更新时间:2006-4-25 23:17:19  文章录入:eclin  责任编辑:ahaoxie

 

Glossary on Soil Science (3)

Saturated Soil : Soil that contains the maximum amount of water possible. In such soils, all the pores are filled with water.

Silty Clay: Soil material that contains 40% or more clay and 40% or more silt.

Soil : The naturally occurring unconsolidated material on the surface of the earth that has been  influenced by parent material, climate (including the effects of moisture and temperature), macro-and micro-organisms, and relief, all acting over a period of time to produce soil that may differ from the material from which it was derived in many physical, chemical, mineralogical, biological, and morphological properties.

Soil Atmosphere: The gaseous phase of the soil, being that volume not occupied by solids or liquids.

Soil Bulk Density: The mass of dry soil per unit bulk volume (Mg m-3 or g cm-3). The bulk volume is determined before the soil is dried to constant weight at 105° C.

Soil Colloids: Soil colloids are substances of very small particle size, either mineral (e.g. clay) or

organic (e.g. humus), which therefore have a large surface area per unit volume.

Soil pH: The pH of a solution in equilibrium with soil. It is determined by means of a glass, quinhydrone, or other suitable electrode or indicator at a specified soil-solution ratio in a specified

solution, usually distilled water, 0.01 M CaCl , or 1 M KCl.

Soil Pores: The part of the bulk volume of soil not occupied by soil particles.

Soil Water: Soil water is understood to be the equilibrium solution in the soil; pure water refers to the chemically pure compound H O. Water in soil is subject to several force fields originating from

the presence of the soil solid phase, the dissolved salts, the action of external gas pressure, and the

gravitational field.

Solubility : The quantity of solute that dissolves in a given quantity of solvent to form a saturated

solution. The solubility of a substance depends on the temperature. Generally, for a solid in a

liquid, solubility increases with temperature; for a gas, solubility decreases.

Transformation : The process of changing the form of a substance.

Transpiration : Water lost from the surface of a plant, mainly via the stomata.

Water Table: The upper surface of groundwater or that level in the ground where the water is at atmospheric pressure.

Weathering : The breakdown of rocks and minerals at and below the Earth’s surface by the action of physical and chemical processes.

 

The end!

 

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