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There are 12 soil orders (the top hierarchical level) in soil taxonomy. [2] [3] The names of the orders end with the suffix -sol. The criteria for the different soil orders include properties that reflect major differences in the genesis of soils. [4] The orders are: Alfisol – soils with aluminium and iron.
The US soil taxonomic hierarchy includes orders, suborders, great groups, subgroups, families and series, with each series representing a unique kind of soil. In the United States, over 19,000 soil series have been identified. [1]
This is a list of U.S. state soils. A state soil is a soil that has special significance to a particular state . Each state in the United States has selected a state soil, twenty of which have been legislatively established.
USDA soil taxonomy, with 10 soil orders came out in 1975. It was revised into the 2nd edition with 12 soil orders in 1999. In 1933 Franklin D. Roosevelt created the Soil Erosion Service under the Department of the Interior. Hugh Hammond Bennett, after a 30-year career with the Bureau of Chemistry and Soils, was first chief and within 2 years ...
This is the list of the 32 Reference Soil Groups in the sequence of the key (Chapter 4 of the WRB Manual), including the codes (Chapter 6 of the WRB Manual). This list is mainly taken from Table 2 (Chapter 1) of the WRB Manual. [1] Soils with thick organic layers. HS Histosol (with thick organic layers) Soils with strong human influence
Ultisol, commonly known as red clay soil, is one of twelve soil orders in the United States Department of Agriculture soil taxonomy. The word "Ultisol" is derived from "ultimate", because Ultisols were seen as the ultimate product of continuous weathering of minerals in a humid, temperate climate without new soil formation via glaciation .
Soil texture triangle showing the USDA classification system based on grain size. 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.
Oxisols are a soil order in USDA soil taxonomy, best known for their occurrence in tropical rain forest within 25 degrees north and south of the Equator. In the World Reference Base for Soil Resources (WRB), [1] they belong mainly to the ferralsols, but some are plinthosols or nitisols. Some oxisols have been previously classified as laterite ...