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  2. USDA soil taxonomy - Wikipedia

    en.wikipedia.org/wiki/USDA_soil_taxonomy

    The soil suborders within an order are differentiated on the basis of soil properties and horizons which depend on soil moisture and temperature. Forty-seven suborders are recognized in the United States. [6] The soil great group category is a subdivision of a suborder in which the kind and sequence of soil horizons distinguish one soil from ...

  3. Soil matrix - Wikipedia

    en.wikipedia.org/wiki/Soil_matrix

    In soils, clay is a soil textural class and is defined in a physical sense as any mineral particle less than 2 μm (8 × 10 −5 in) in effective diameter. Many soil minerals, such as gypsum , carbonates, or quartz, are small enough to be classified as clay based on their physical size, but chemically they do not afford the same utility as do ...

  4. World Reference Base for Soil Resources - Wikipedia

    en.wikipedia.org/wiki/World_Reference_Base_for...

    The soil belongs to the first RSG, for which it fulfils the set of criteria. The qualifiers available for use with a particular RSG are listed in the key, along with the RSG. Their number is from 40 to 79. All applying qualifiers must be added to the soil name. Qualifiers: The principal qualifiers are added before the name of the RSG.

  5. Unified Soil Classification System - Wikipedia

    en.wikipedia.org/wiki/Unified_Soil...

    Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests Soil Classification Group Symbol Group Name COARSE-GRAINED SOILS. More than 50% retained on No.200 Sieve Gravels. More than 50% of coarse fraction on No. 4 Sieve Clean Gravels. Less than 5% fines Cu ≥ 4 and 1 ≤ Cc ≤ 3 GW Well-graded gravel Cu < 4 and/or Cc < 1 or ...

  6. Soil - Wikipedia

    en.wikipedia.org/wiki/Soil

    Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from soil by restricting the former term specifically to displaced soil. Soil measuring and surveying device

  7. List of minerals - Wikipedia

    en.wikipedia.org/wiki/List_of_minerals

    Amethyst crystals – a purple quartz Apophyllite crystals sitting right beside a cluster of peachy bowtie stilbite Aquamarine variety of beryl with tourmaline on orthoclase Arsenopyrite from Hidalgo del Parral, Chihuahua, Mexico Aurichalcite needles spraying out within a protected pocket lined by bladed calcite crystals Austinite from the Ojuela Mine, Mapimí, Durango, Mexico Ametrine ...

  8. List of minerals recognized by the International ...

    en.wikipedia.org/wiki/List_of_minerals...

    The International Mineralogical Association (IMA) is the international scientific group that recognises new minerals and new mineral names. However, minerals discovered before 1959 did not go through the official naming procedure. Some minerals published previously have been either confirmed or discredited since that date.

  9. Soil classification - Wikipedia

    en.wikipedia.org/wiki/Soil_classification

    Soil texture triangle showing the USDA classification system based on grain size Map of global soil regions from the USDA. For soil resources, experience has shown that a natural system approach to classification, i.e. grouping soils by their intrinsic property (soil morphology), behaviour, or genesis, results in classes that can be interpreted for many diverse uses.