- 行业: Earth science
- Number of terms: 26251
- Number of blossaries: 0
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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 plant nutrient found in relatively small amounts( <100 mg kg-1) in plants. These are usually B, Cl, Cu, Fe, Mn, Mo, Ni, Co, and Zn.
Industry:Earth science
A relationship between two organisms whereby one organism (predator) engulfs and digests the second organism (prey).
Industry:Earth science
A generic class of compounds used as phosphorus fertilizers. Manufactured by the reaction of anhydrous ammonia with orthophosphoric acid or superphosphoric acid to produce either solid or liquid products.
Industry:Earth science
A low mound, knob, hummock, or short irregular ridge, composed of stratified sand and gravel deposited by a subglacial stream as a fan or delta at the margin of a melting glacier; by a supraglacial stream in a low place or hole on the surface of the glacier; or as a ponded deposit on the surface or at the margin of stagnant ice.
Industry:Earth science
A method for estimating microbial numbers in soil based on dilution to extinction.
Industry:Earth science
(i) As a general term, refers to either a discrete non-expansible mica of detrital or authigenic origin or to the micaceous component of interstratified systems, as in illite-smectite. If used to refer to the species, it should meet the following requirements: a) The micaceous layers ideally are non-expansible; b) the octahedral sheet is dioctahedral and aluminous; c) the interlayer cation is primarily potassium; and (4) the composition deviates from that of muscovite in two main ways: 1) A phengitic component is present in which substitution of R2+ cations for octahedral Al is balanced by addition of tetrahedral Si beyond the ideal Si:Al ratio of 3:1 for muscovite. This substitution gives the octahedral sheet an overall negative charge of about 0. 2 to 0. 3 per formula unit. 2) Interlayer vacancies or water molecules amounting to about 0. 2 to 0. 4 atoms per formula unit are compensated by additional tetrahedral Si cations beyond those required by the phengitic component. Where reference is made to the species illite, a clear statement should be made to that effect in order to avoid confusion with the general usage. (ii) In soil taxonomy, the presence of a 1 nm x-ray diffraction peak and greater than or equal to 4% K2O is used to denote the presence of illite.
Industry:Earth science
A hard layer, containing calcium carbonate, gypsum, or other binding material, exposed at the surface in a desert region.
Industry:Earth science
A forest humus type characterized by intimate incorporation of organic matter into the upper mineral soil (i.e. a well developed A horizon) in contrast to accumulation on the surface. (Sometimes differentiated into the following Groups: Vermimull, Rhizomull, and Hydromull).
Industry:Earth science
A mineral soil horizon that is characterized by the illuvial accumulation of amorphous materials composed of aluminum and organic carbon with or without iron. The spodic horizon has a certain minimum thickness, and a minimum quantity of extractable carbon plus iron plus aluminum in relation to its content of clay.
Industry:Earth science
A soil capable of being molded or deformed continuously and permanently, by relatively moderate pressure, into various shapes.
Industry:Earth science
