- 行业: Earth science
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An international scientific society that fosters the transfer of knowledge and practices to sustain global soils. Based in Madison, WI, and founded in 1936, SSSA is the professional home for 6,000+ members dedicated to advancing the field of soil science. It provides information about soils in ...
A map showing the distribution of soils or other soil map units in relation to the prominent physical and cultural features of the earth's surface. The following kinds of soil maps are recognized in the USA:
* detailed soil map-A soil map on which the boundaries are shown between all soils that are significant to potential use as field management systems. The scale of the map will depend upon the purpose to be served, the intensity of land use, the pattern of soils, and the scale of teh other cartographic materials available. Traverses are usually made at 400-m, or more frequent, intervals. Commonly a scale of 10 cm = 1609 m is now used fro field mapping in the USA
* detailed reconnaissance soil map-A reconnaissance map on which some areas or features are shown in greater detail than usual, or than others.
* generalized soil map-A small-scale soil map which shows the general distribution of soils within a large area and thus in less detail than on a detailed soil map. Generalized soil maps may vary from soil association maps of a county, on a scale of 1 cm = 633 m, to maps of larger regions showing associations dominated by one or more great soil groups.
* reconnaissance soil map-A map showing the distribution of soils over a large area as determined by traversing the area at intervals varying from about 800 m to several kilometers. The units shown are soil associations. Such a map is usually made only for exploratory purposes to outline areas of soil suitable for more intensive development. The scale is usually much smaller than for detailed soil maps.
* schematic soil map-A soil map compiled from scant knowledge of the soils of new and undeveloped regions by the application of available information about the soil-formation factors of the area. Usually on a small scale ( 1:1 000 000 or smaller).
Industry:Earth science
Total volume of water infiltrated per unit area of soil surface during a specified time period. Contrast with infiltration flux or rate.
Industry:Earth science
The capacity of a soil to function within ecosystem boundaries to sustain biological productivity, maintain environmental quality, and promote plant and animal health.
Industry:Earth science
The relative proportions of the various soil separates in a soil as described by the classes of soil texture shown in Fig. 1. The textural classes may be modified by the addition of suitable adjectives when rock fragments are present in substantial amounts; for example, ""stony silt loam."" (For other modifiers see also rock fragments.) The sand, loamy sand, and sandy loam are further subdivided on the basis of the proportions of the various sand separates present. The limits of the various classes and subclasses are as follows:
* clay - Soil material that contains 40% or more clay, <45% sand, and <40% silt.
* clay loam - Soil material that contains 27 to 40% clay and 20 to 45% sand.
* loam - Soil material that contains 7 to 27% clay, 28 to 50% silt, and <52% sand.
* loamy sand - Soil material that contains between 70 and 91% sand and the percentage of silt plus 1.5 times the percentage of clay is 15 or more; and the percentage of silt plus twice the percentage of clay is less than 30.
** loamy coarse sand - Soil material that contains 25% or more very coarse and coarse sand, and <50% any other one grade of sand.
** loamy sand - Soil material that contains 25% or more very coarse, coarse, and medium sand, <25% very coarse and coarse sand, and <50% fine or very fine sand.
** loamy fine sand - Soil material that contains 50% or more fine sand (or) <25% very coarse, coarse, and medium sand and <50% very fine sand.
** loamy very fine sand - Soil material that contains 50% or more very fine sand.
* sand - Soil material that contains 85% or more of sand; percentage of silt, plus 1.5 times the percentage of clay, shall not exceed 15.
** coarse sand - Soil material that contains 25% or more very coarse and coarse sand, and <50% any other one grade of sand.
** sand - Soil material that contains 25% or more very coarse, coarse, and medium sand, <25% very coarse and coarse sand, and <50% fine or very fine sand.
** fine sand - Soil material that contains 50% or more fine sand (or) <25% very coarse, coarse, and medium sand and <50% very fine sand.
** very fine sand - Soil material that contains 50% or more very fine sand.
* sandy clay - Soil material that contains 35% or more clay and 45% or more sand.
* sandy clay loam - Soil material that contains 20 to 35% clay, <28% silt, and >45% sand.
* sandy loam - Soil material that contains 7 to 20% clay, more than 52% sand, and the percentage of silt plus twice the percentage of clay is 30 or more; or less than 7% clay, less than 50% silt, and more than 43% sand.
** coarse sandy 1oam - Soil material that contains 25% or more very coarse and coarse sand and <50% any other one grade of sand.
** sandy loam - Soil material that contains 30% or more very coarse, coarse, and medium sand, but <25% very coarse and coarse sand, and <30% very fine or fine sand, or <15% very coarse, coarse, and medium sand and <30% either fine sand or very fine sand and 40% or less fine plus very fine sand.
** fine sandy loam - Soil material that contains 30% or more fine sand and <30% very fine sand (or) between 15 and 30% very coarse, coarse, and medium sand, or >40% fine and very fine sand, at least half of which is fine sand, and <15% very coarse, coarse, and medium sand.
** very fine sandy loam - Soil material that contains 30% or more very fine sand and <15% very coarse, coarse, and medium sand (or) >40% fine and very fine sand, more than half of which is very fine sand and <15% very coarse, coarse, and medium sand.
* silt - Soil material that contains 80% or more silt and <12% clay.
* silty clay - Soil material that contains 40% or more clay and 40% or more silt.
* silty clay loam - Soil material that contains 27 to 40% clay and <20% sand.
* silt loam - Soil material that contains 50% or more silt and 12 to 27% clay (or) 50 to 80% silt and <12% clay.
Industry:Earth science
Si<sub>4</sub>Mg<sub>3</sub>O<sub>10</sub>(OH)<sub>2</sub> A trioctahedral magnesium silicate mineral with a 2:1 type layer structure but without isomorphous substitution. May occur in soils as an inherited mineral.
Industry:Earth science
A transient localized soil property which is a combined measure of a given pedon's, horizon's, or other soil subunit's solid phase adhesive and cohesive status. This property is most easily affected by changes in soil water content and bulk density, although other factors including texture, mineralogy, cementation, cation composition and organic matter content also affect it. In situ characterization with soil penetrometer is the most common agricultural measure of soil strength, although measurements of other engineering components of strength on disturbed samples are also regarded as valid characterizations.
Industry:Earth science
A transient localized soil property which is a combined measure of a given pedon's, horizon's, or other soil subunit's solid phase adhesive and cohesive status. This property is most easily affected by changes in soil water content and bulk density, although other factors including texture, mineralogy, cementation, cation composition and organic matter content also affect it. In situ characterization with soil penetrometer is the most common agricultural measure of soil strength, although measurements of other engineering components of strength on disturbed samples are also regarded as valid characterizations.
Industry:Earth science
(i) The rate of diffusion of oxygen through soil as defined by Fick's law. (ii) A measurement of diffusion governed oxygen reduction rate at the surface of platinum microelectrodes used to assess the oxygen supplying ability of the soil relative to the needs of plant roots, usually referred to as soil ODR.
Industry:Earth science
The tendency for a soil particle or soil mass to resist hydration, usually quantified using the water drop penetration time test. See also soil wettability, water drop penetration time.
Industry:Earth science
A great soil group of the intrazonal order and calcimorphic suborder, formed on calcium-rich parent materials under deciduous forest, and possessing a high base status but lacking a pronounced illuvial horizon.
Industry:Earth science
