Gley soil sample from Sheffield

Gley soil in soil science is a type of hydric soil which exhibits a greenish-blue-grey soil color due to wetland conditions. Soil science is the study of Soil as a Natural resource on the surface of the Earth including soil formation, classification and mapping A hydric soil is a soil that formed under conditions of saturation flooding or ponding long enough during the growing season to develop anaerobic conditions in the upper part Soil color often indicates Soil moisture status and is used for determining Hydric soils Often described by using general terms such as dark brown yellowish brown A wetland is an area of Land consisting of Soil that is Saturated with Moisture, such as a Swamp, Marsh, or Bog On exposure to the air, gley colors are transformed to a mottled pattern of reddish, yellow or orange patches. During gley soil formation (a process known as Gleying), the oxygen supply in the soil profile is restricted due to soil moisture at saturation. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the A soil horizon is a specific layer in the Soil which measures parallel to the soil surface and possesses physical characteristics which differ from the layers above and Water content or moisture content is the quantity of Water contained in a material such as Soil (called soil moisture) rock, Anaerobic micro-organisms support cellular respiration by using alternatives to free oxygen as electron acceptors. An anaerobic organism is any Organism that does not require Oxygen for growth and may even die in its presence Cellular respiration is the set of the metabolic reactions and processes that take place in Organisms cells to convert biochemical energy from This is most often the case when the sesquioxide of iron, ferric oxide is reduced to ferrous oxide by the removal of oxygen. A sesquioxide is an Oxide containing three atoms of Oxygen with two Atoms (or radicals of another element Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Iron(III oxide —also known as ferric oxide, Hematite, red iron oxide, synthetic maghemite, colcothar, or simply Rust —is Iron(II oxide, also known as ferrous oxide, iron oxide/oxidized iron or more commonly rusted These reduced mineral compounds produce the gley soil color.

Gley soils may be sticky and hard to work, especially where the gleying is caused by surface water, held up on a slowly permeable layer. However, some ground-water gley soils have permeable lower horizons, including some sands, for example in hollows within sand dune systems, known as slacks, and in some alluvial situations. Permeability in the Earth sciences (commonly symbolized as κ, or k) is a measure of the ability of a material (typically a rock or unconsolidated A soil horizon is a specific layer in the Soil which measures parallel to the soil surface and possesses physical characteristics which differ from the layers above and Alluvium (from the Latin, alluvius, from alluere, "to wash against" is Soil or Sediments deposited by a river or other running

Groundwater gley soils develop where drainage is poor because the water table (phreatic surface) is high, whilst Surface-water gleying occurs when precipitation inputs at the surface do not drain freely through the ground. Drainage is the natural or artificial removal of surface and sub-surface water from a given area The water table is the level at which the ground water pressure is equal to Atmospheric pressure. The term phreatic is used in Earth sciences to refer to matters relating to ground water below the static Water table (the word originates from the Greek In Meteorology, precipitation (also known as one class of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric A reducing environment exists in the saturated layers, which become mottled greyish-blue or brown because of the content of ferrous iron and organic matter. Iron(II oxide, also known as ferrous oxide, iron oxide/oxidized iron or more commonly rusted The presence of reddish or orange mottles indicates localised re-oxidation of ferrous salts in the soil matrix, and is often associated with root channels, animal burrows or cracking of the soil material during dry spells.

A stagnohumic gley soil in a forest plantation in mid-Wales, U. K. The organic-rich topsoil is over a grey and orange mottled subsoil developed in glacial till ("boulder clay")

Most soil classifications divide the gley soils into surface-water gleys (also known as stagnogleys) and gleys proper, or groundwater gleys, the former having a slowly pemeable lower subsoil, leading to a "perched" water table, the latter being in low ground or basin situations where the natural groundwater table is constantly high enough to influence the soil profile. Till is unsorted glacial sediment Glacial drift is a general term for the coarsely graded and extremely heterogeneous Sediments of glacial origin Soil classification deals with the systematic categorization of Soils based on distinguishing characteristics as well as criteria that dictate choices in use

See also

• Anaerobic respiration
• Redox