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  2. USDA soil taxonomy - Wikipedia

    en.wikipedia.org/wiki/USDA_soil_taxonomy

    Extragrade features are aberrant properties which prevent that soil from being included in another soil classification. About 1,000 soil subgroups are defined in the United States. [6] A soil family category is a group of soils within a subgroup and describes the physical and chemical properties which affect the response of soil to agricultural ...

  3. 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.

  4. Soil survey - Wikipedia

    en.wikipedia.org/wiki/Soil_survey

    The most current soil survey data is made available for high end GIS users such as professional consulting companies and universities. Typical information in a published county soil survey includes the following: [1] a brief overview on how to use the survey; a general soil map for comparing the sustainability of large sections of the county

  5. Unified Soil Classification System - Wikipedia

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

    The Unified Soil Classification System (USCS) is a soil classification system used in engineering and geology to describe the texture and grain size of a soil. The classification system can be applied to most unconsolidated materials, and is represented by a two-letter symbol.

  6. Soil texture - Wikipedia

    en.wikipedia.org/wiki/Soil_texture

    Soil texture is a classification instrument used both in the field and laboratory to determine soil classes based on their physical texture. Soil texture can be determined using qualitative methods such as texture by feel, and quantitative methods such as the hydrometer method based on Stokes' law .

  7. World Reference Base for Soil Resources - Wikipedia

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

    Since the 19th century, several countries developed national soil classification systems. During the 20th century, the need for an international soil classification system became more and more obvious. From 1971 to 1981, the Food and Agriculture Organization (FAO) and UNESCO published the Soil Map of the World, 10 volumes, scale 1 : 5 M). [2]

  8. Soil type - Wikipedia

    en.wikipedia.org/wiki/Soil_type

    A soil type is a taxonomic unit in soil science. All soils that share a certain set of well-defined properties form a distinctive soil type. [1] Soil type is a technical term of soil classification, the science that deals with the systematic categorization of soils. Every soil of the world belongs to a certain soil type. Soil type is an ...

  9. Soil morphology - Wikipedia

    en.wikipedia.org/wiki/Soil_morphology

    Since the origin of agriculture, humans have understood that soils contain different properties which affect their ability to grow crops. [4] However, soil science did not become its own scientific discipline until the 19th century, and even then early soil scientists were broadly grouped as either "agro-chemists" or "agro-geologists" due to the enduring strong ties of soil to agriculture.