Glossary of Soil Science Terms - Browse
wash (dry wash) (colloquial: western USA) The broad, flat-floored channel of an ephemeral stream, commonly with very steep to vertical banks cut in alluvium. Note: When channels reach intersect zones of ground-water discharge they are more properly classed as “intermittent stream” channels. Synonym arroyo. Compare gully (Hawley and Parsons, 1980).
washover fan A fan-like deposit of sand washed over a barrier island or spit during a storm and deposited on the landward side. Washover fans can be small to medium sized and completely subaerial, or they can be quite large and include subaqueous margins extending into adjacent lagoons or estuaries. Large fans can be subdivided into sequential parts: ephemeral washover channel (microfeature) cut through dunes or beach ridges, subaerial washover fanback-barrier flats, (subaqueous) washover-fan flat, (subaqueous) washover-fan slope. Subaerial portions can range from barren to completely vegetated (Subaqueous Soil Subcommittee, 2005).
washover-fan apron (not preferred) use washover-fan flat.
washover-fan slope A subaqueous extension of a washover-fan flat that slopes toward deeper water of a lagoon or estuary and away from the washover-fan flat. Compare washover-fan flat (Subaqueous Soil Subcommittee, 2005).
washover-fan flat A gently sloping, fan-like, subaqueous landform created by overwash from storm surges that transports sediment from the seaward side to the landward side of a barrier island ( Jackson, 1997). Sediment is carried through temporary overwash channels that cut through the dune complex on the barrier spit (Fisher and Simpson, 1979; Boothroyd et al., 1985; Davis, 1994) and spill out onto the lagoon-side platform where they coalesce to form a broad belt. Also called storm-surge platform flat (Boothroyd et al., 1985) and washover fan apron ( Jackson, 1997). Compare washover fan slope (Subaqueous Soil Subcommittee, 2005).
wasteland Land not suitable for, or capable of, producing materials or services of value. Compare miscellaneous areas.
water [soil survey] A generic map unit for any permanent, open body of water (pond, lake, reservoir, etc.) that does not support rooted plants (Schoeneberger and Wysocki, personal communication, 2013).
water balance A procedure whereby water inputs and outputs are accounted for in a given soil leaving a balance called the storage.
water repellent soil Refer to soil hydrophobicity, water drop penetration time.
water (or matric) suction (no longer used in SSSA publications) The preferred term is matric potential. Refer to soil water, soil water potential.
water content Refer to soil water, water content.
water drop penetration time (WDPT) A measure of soil water repellency which uses the imbibition time of drops of prescribed aqueous solutions as a discriminator.
water retention A property of soil that results from the attraction of the soil matrix for water.
water table The upper surface of ground water or that level in the ground where the water is at atmospheric pressure.
water table, perched A saturated layer of soil that is separated from any underlying saturated layers by an unsaturated layer.
water tension Refer to soil water, soil water potential.
water use efficiency Dry matter or harvested portion of crop produced per unit of water consumed.
water-lain moraine A terminal, end, or recessional moraine formed subaqueously by a glacier that terminated in a water body (e.g., glacial lake, sea, or ocean). A water-lain moraine may occur at the present land surface as a result of isostatic rebound or lake drainage. Compared to a land-based moraine of similar origin, a water-lain moraine displays sediment (till) modification by wave and/or current action and has a somewhat subdued topography (Schoeneberger and Wysocki, personal communication, 2013).
water-release curve Refer to soil water characteristic.
water-retention curve Refer to soil water characteristic.
water-soluble phosphate That part of the phosphorus in a fertilizer that is soluble in water as determined by prescribed chemical tests.
water-stable aggregate A soil aggregate that is stable to the action of water such as falling drops, or agitation as in wet-sieving analysis.
waterlogged An informal term for materials saturated or nearly saturated with water.
waterway (a) A general term for a way or channel, either natural (as a river) or artificial (as a canal), for conducting the flow of water. (b) A navigable body or stretch of water available for passage; a watercourse. Compare drainageway. ( Jackson, 1997).
wave-built terrace A gently sloping coastal feature at the seaward or lakeward edge of a wave-cut platform, constructed by sediment brought by rivers or drifted along the shore or across the platform and deposited in the deeper water beyond. Compare submerged wavebuilt terrace, beach plain, strand plain ( Jackson, 1997).
wave-cut terrace (not recommended) use wavebuilt terrace.
wave-cut platform A gently sloping surface produced by wave erosion, extending into the sea or lake from the base of the wave-cut cliff. This feature represents both the wave-cut bench and the abrasion platform. Compare submerged wave-cut platform ( Jackson, 1997).
wave-worked till plain A glaciated land area that has the characteristics of a till plain, but that was also inundated by a glacial lake. The area possesses a gently undulating till-topography rather than a distinctive, low-relief lake plain surface. Lacustrine sediments, however, are absent or occur only sparsely, but a wave/ current-modified, surficial mantle may commonly exist atop the till. Topographic highs, which were once islands, may possess shore features (e.g., wave-cut scarps, strandlines, beach deposits). Compare till-floored lake plain (Schoeneberger and Wysocki, personal communication, 2013).
wavelength Distance between two repetitive points on a sine wave.
weathering The breakdown and changes in rocks and sediments at or near the earth’s surface produced by biological, chemical, and physical agents or combinations of them. Compare chemical weathering and mechanical weathering.
wedge soil structure A type of soil structure. Compare soil structure and soil structure types.
weeding Refer to tillage, weeding.
weight The force which an object exerts in a gravitational field because of its mass; weight = mg.
weir A low dam or overflow structure specified geometry placed across an open channel to measure the discharge from a unique water level-discharge relationship called the rating curve.
welded soil (not preferred) Refer to overprinted soil.
welded tuff A glass-rich, pyroclastic rock composed of volcanic ash indurated at the time of deposition by the welding together of its glass shards under the combined action of the heat retained by particles, the weight of overlying material, and hot gasses. It is generally composed of silica pyroclasts and appears banded or streaked ( Jackson, 1997).
welding (a) Consolidation of sediments (especially of clays) by pressure resulting from the weight of superincumbent material or from earth movement, characterized by cohering particles brought within the limits of mutual molecular attraction as water is squeezed out of the sediments. (b) The diagenetic process whereby discrete crystals and/or grains become attached to each other during compaction, often involving pressure solution and pressure transfer ( Jackson, 1997).
well A pipe perforated for a prescribed interval (depth increment) in order to equilibrate with the adjoining aquifer for measurement of the depth to the free-water surface, that is, water table.
well drained A soil drainage class characterized by the lack of any evidence of seasonal high water tables in the top 91 cm (36 in) of the soil profile.
wet density Ratio of the wet mass of soil to the bulk volume of soil.
wet prairies Refer to marsh.
wetland Land that has (i) a predominance of hydric soils; and (ii) is inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and under normal circumstances does support, a prevalence of hydrophytic vegetation typically adapted for life in saturated soil conditions.
wettability Refer to soil wettability.
wetting front The boundary between the wetted region and the dry region of soil during infiltration.
wheel track planting Refer to tillage, wheel track planting.
white rot fungus Fungus that attacks lignin, along with cellulose and hemicellulose, leading to complete decomposition of wood; some members are important in bioremedtiation of xenobiotics that resemble lignin, that is, polycyclic aromatic hydrocarbons.
wild-flooding Refer to irrigation, wild-flooding.
wilting coefficient (no longer used in SSSA publications) A calculated value of the approximate wilting point or permanent wilting percentage. Calculated as follows:Wilting coefficient = Hygroscopic coefficient/0.68orWilting coefficient = Moisture equivalent/1.84
wilting point Refer to permanent wilting point.
wind gap A former water gap now abandoned by the stream that formed it, suggesting stream piracy or stream diversion (Hawley and Parsons, 1980).
wind-tidal flat A broad, low-lying, nearly-level sand flat that is alternately inundated by ponded rainwater or by wind-driven bay or estuarine water from storm surges or seiche. Frequent salinity fluctuations and prolonged periods of subaerial exposure preclude establishment of most types of vegetation except for mats of filamentous blue-green algae. Compare tidal flat (Subaqueous Soil Subcommittee, 2005; Fisk, 1959).
windbreak Refer to erosion, windbreak.
window [tectonic] An eroded area of a thrust sheet, commonly a basin or valley floor, that exposes the incongruous bedrock stratigraphy beneath the thrustsheet; a particular structural or stratigraphic relationship is implied, rather than a particular topographic form. Common in the Appalachian and Rocky Mountain margins( Jackson, 1997; Thornbury, 1969; Schoeneberger and Wysocki, personal communication, 2013). Synonym: fenster.
windthrow Refer to tree-tip.
windthrow mound Refer to tree-tip mound.
woody organic materials Refer to organic materials.
woody peat [soil taxonomy] An accumulation of organic material that is predominantly composed of trees, shrubs, and other woody plants. Compare herbaceous peat, moss peat, sedimentary peat, peat, muck, and mucky peat. (Soil Survey Staff, 1993).
work A term used to indicate the energy required to move an object a certain distance.