- 行业: Earth science
- Number of terms: 26251
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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 ...
Crystallization into two or more chemically identical but crystallographically distinct forms.
Industry:Earth science
A suborder of the intrazonal soil order, consisting of saline and sodic soils formed under imperfect drainage in arid regions and including the great soil groups Solonchak or Saline soils, Solonetz soils, and Soloth soils.
Industry:Earth science
In soil survey a map unit that is a miscellaneous area, which is barren alluvial areas of unstablilized sand silt, clay or gravel reworked by frequently by stream activity.
Industry:Earth science
Movement of ions and water into the plant root from diffusion along a chemical potential gradient.
Industry:Earth science
A subdivision of a soil order comprising a large group of soils in which sesquioxides increased relative to silica during soil formation.
Industry:Earth science
Design curves giving prescribed rates of surface runoff for different levels of crop production, and which may vary according to size of drainage area.
Industry:Earth science
Any organic or inorganic material of natural or synthetic origin (other than liming materials) that is added to a soil to supply one or more plant nutrients essential to the growth of plants. These may include:
* acid-forming - Fertilizer that, after application to and reaction with soil, increases residual acidity and decreases soil pH.
* blended - A mechanical mixture of different fertilizer materials.
* bulk-blended - A physical mixture of dry granular fertilizer materials to produce specific fertilizer ratios and grades. Individual granules in the bulk blended fertilizer do not have the same ratio and content of plant food as does the mixture as a whole.
* complete - A chemical compound or a blend of compounds that contains significant quantities of all three primary nutrients, N, P, and K. It may contain other plant nutrients.
* compound - A fertilizer formulated with two or more plant nutrients.
* controlled-release - A fertilizer term used interchangeably with delayed release, slow release, controlled availability, slow acting, and metered release to designate a controlled dissolution of fertilizer at a lower rate than conventional water-soluble fertilizers. Controlled-release properties may result from coatings on water-soluble fertilizers or from low dissolution and/or mineralization rates of fertilizer materials in soil.
* granular - Fertilizer particles sized between an upper and lower limit or between two screen sizes, usually within the range of 1 to 4 mm and often more closely sized. The desired size may be obtained by agglomerating smaller particles, crushing and screening larger particles, controlling size in crystallization processes, or prilling.
* injected - Placement of fertilizer into the soil either through use of pressure or nonpressure systems.
* inorganic - A fertilizer material in which carbon is not an essential component of its basic chemical structure.
* liquid - Fertilizer wholly or partially in solution that can be handled as a liquid, including clear liquids and liquids containing solids in suspension.
* mixed - Two or more fertilizer materials blended or granulated together into individual mixes. The term includes dry mix powders, granulated, clear liquid, suspension, and slurry mixtures.
* organic - A material containing carbon and one or more plant nutrients in addition to hydrogen and/or oxygen.
* pop-up - Fertilizer placed in small amounts in direct contact with the seed.
* salt index - The ratio of the decrease in osmotic potential of a solution containing a fertilizer compound or mixture to that produced by the same weight of NaNO3 x 100.
* sidedressed - A fertilizer application usually banded to the side of crop rows after plant emergence.
* slow-release - See fertilizer, controlled-release.
* starter - A fertilizer applied in relatively small amounts with or near the seed usually during planting for the purpose of accelerating early growth of the crop plants.
* suspension - A fluid fertilizer containing dissolved and undissolved plant nutrients. The undissolved plant nutrients are kept in suspension with a suspending agent, usually a swelling type clay. The suspension must be flowable enough to be mixed, pumped, agitated, and applied to the soil in a homogeneous mixture.
* top-dressed - A non-incorporated surface application of fertilizer to a soil after the crop has been established.
Industry:Earth science
One of the eight classes of land in the land capability classification of the U. S. Natural Resource Conservation Service; distinguished according to the risk of land damage or the difficulty of land use; they include:
Land suitable for cultivation and other uses.
* Class I - Soils that have few limitations restricting their use.
* Class II - Soils that have some limitations, reducing the choice of plants or requiring moderate conservation practices.
* Class III - Soils that have severe limitations that reduce the choice of plants or require special conservation practices, or both.
* Class IV - Soils that have very severe limitations that restrict the choice of plants, require very careful management or both.
Land generally not suitable for cultivation (without major treatment).
* Class V - Soils that have little or no erosion hazard, but that have other limitations, impractical to remove, that limit their use largely to pasture, range, woodland, or wildlife food and cover.
* Class VI - Soils that have severe limitations that make them generally unsuited for cultivation and limit their use largely to pasture or range, woodland, or wildlife food and cover.
* Class VII - Soils that have very severe limitations that make them unsuited to cultivation and that restricts their use largely to grazing, woodland, or wildlife.
* Class VIII - Soils and landforms that preclude their use for commercial plant production and restrict their use to recreation, wildlife, water supply, or aesthetic purposes.
Industry:Earth science
Formerly in the U. S. soil classification systems prior to publication of USDA Soil Taxonomy (1975). (i) The lowest unit in the natural system of soil classification; a subdivision of a soil series and consisting of or describing soils that are alike in all characteristics including the texture of the A horizon or plow layer; (ii) In Europe, roughly equivalent to a great soil group.
Industry:Earth science
