Soil Classification in the United States. Soil Morphology, Genesis, and Classification (SPS 350). Why classify soils?. Whenever we call things by group names, or give them labels that inform us of their important properties, we are doing classification.
Soil Morphology, Genesis, and Classification (SPS 350)
Suitability for different uses
Method of soil formation
Hierarchical soil classification groups soils into increasing levels of generality between these two concepts –pedons and polypedons
Agric (A or B)
SulfuricSoil subsurface diagnostic horizons
Diagnostic subsurface horizons form below the soil surface. Usually, they are B horizons but diagnostic subsurface horizons may include parts of A or E horizons. Some soils do not have a diagnostic subsurface horizon.
1. Soil Moisture Regimes
(refers to the presence or absence of water saturated conditions or plant-available soil water at a defined section of the soil (control section)
(Based on mean tempt. differences of soils at 50 cm depth)
Great groups are subdivisions of suborders.
Great groups are defined largely by the presence or absence of diagnostic horizons and the arrangement of those horizons.
Formed by adding formative elements to the suborder names (Table 3.7 of Textbook, pp. 113)
Examples of Great group names:
(See next figure for complete structure of Soil Taxonomy)