SPECIAL PUBLICATION NO. 27


sod peat mining Peat mining process in which the top layer of peat is
cut and compressed by the machinery before being extruded onto the
field to dry.

soil A natural, three dimensional body at the Earth's surface which
has properties resulting from the integrated effect of climate and organic
matter on present rock material, as conditioned in response to topogra-
phy; capable of supporting plant material.

solvent extraction Process which selectively separates components
of an organic substance by means of reacting with a solvent. The
absorbed compounds are subsequently stripped from the solvent.

sphagnum moss peat (American Society of Testing and Materials
(ASTM) classification) Peat which must contain at least 66.66 percent
Sphagnum moss fibers, by weight. NOTE: The ASTM is presently in the
process of revising this classification. The above term will no longer be
used.

stoichiometric proportions With reference to a compound or a phase,
pertaining to the exact proportions of its constituents specified by its
chemical formula. It is generally implied that a stoichiometric phase does
not deviate measurably from its ideal composition.

subsidence The lowering of the upper surface of a peat deposit due
to a reduction in volume; caused by a number of factors: shrinkage due
to dessication, consolidation due to loss of bouyant force of water or
loading, compaction due to tillage, erosion by wind, fire damage or bio-
chemical oxidation.

sulfur An orthorhombic mineral, the native nonmetallic element S. It
occurs in yellow crystals or in masses or layers often associated with
limestone, gypsum and other minerals; used in the production of sulfuric
acid, in petroleum refining, chemical production, iron and steel, paper,
industrial explosives and many other uses.

swamp A water-saturated area, intermittently or permanently cov-
ered with water, having shrub and tree-type vegetation.

synthesis gas Those gases produced during gasification of peat
which can be upgraded by hydrocracking to produce synthetic natural
gas.

talc An extremely soft, whitish, greenish or grayish monoclinic min-
eral: Mg3Si4010(OH)2. It has a characteristic soapy or greasy feel and a
hardness of 1 on Mohs' scale, and it is easily cut with a knife. Talc is a
common secondary mineral derived by alteration (hydration) of non-
aluminous magnesium silicates (such as olivine, enstatite and tremolite)


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