USDA Classification of Soils

In the classification established by the staff of the United States Department of Agriculture (USDA) there are six categories in the soil taxonomy  

Suborder (60). Suborders are subdivisions of orders that emphasize gentic homogeneity. The presence or absence of properties associated with wetness, climatic environment, major parent material, and vegetation. 

Family. Families are sound in soils with a subgroup having similar physical and chemical properties affecting their response to management and especially to the penetration of plant roots. Differences in texture, mineralogy, temperature, and soil depth are bases for family differentiation. 

Series (ca. 17,000 in the U.S.). Its differentiating characteristics are based primarily on the kind and arrangement of horizons, color, texture, structure, consistence, reaction of horizons, chemical, and mineralogical properties of the horizons. 

Soil order Suborders Alfisols Aqualfs Boralfs Udalfs Ustalfs Xeralfs 

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