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Classification, Properties, and Management of Aridisols

Soil Taxonomy

Aridisols Slide 6

This presentation illustrates the classification, properties, and management of aridic soils using the technical language of soil classification developed in the book Soil Taxonomy by the Natural Resource Conservation Service of the United States Department of Agriculture, formerly the Soil Conservation Service. Through its use, reproducible soil identification can be made anywhere in the world. Published in 1975, Soil Taxonomy is now used by more than 45 countries as a national soil classification system. Since 1975, the knowledge gained through world application has led to significant changes in the system. The current edition (9th) can be accessed on the Web.

Aridisols Slide 7

Soil Taxonomy classifies soils at six levels or categories based on diagnostic soil horizons and soil climatic conditions. The broadest category is Order. Lower categories, in which classes are successively more narrowly defined, are the Suborder, Great Group, Subgroup, Family, and Series.

Aridisols Slide 8

Soil class names have meaning. They are composed of descriptive syllables, mostly from Latin and Greek roots. For example, the syllable "id" is used as a suffix to all names in the Aridisol Order. "Id" comes from the Latin word aridus meaning dry.

Aridisols Slide 9

The Aridisol soil Order is one of eleven Orders recognized in Soil Taxonomy. (Originally ten Orders, the eleventh, Andisol, has been added to distinguish at the highest level those soils derived from volcanic-glass.) Before we examine the taxonomic hierarchy of the Aridisol Order, we'll discuss the two main criteria used to classify Aridisols: the aridic soil moisture regime and diagnostic soil horizons.

Aridisols Slide 10

Five soil moisture regimes characterize the presence or absence of groundwater or water held at a tension in the soil at which it is available to most plants. This graph depicts the soil water balance in an aridic soil moisture regime. The orange area represents the soil moisture deficit which occurs when evapotranspiration exceeds precipitation. Under these conditions plants do not have water continuously available except for brief periods.

Aridisols Slide 11

Thus, all Aridisols require irrigation to support cultivated crops.

Introduction to Aridic Soils | Soil Taxonomy | Introduction to Soil Horizons | The Horizons | Suborders and Great Groups | Argid Suborder | Orthid Suborder | Subgroups | Families | Non-Aridisols | Irrigation | Saline Soils | Sodic and Saline-Sodic Soils | Final Considerations

Last revised: 24 November 2003
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