PEDOLOGIC CLASSIFICATION OF PEAT

Peat is classified in the order Histosols in the U.S. Department of Agriculture pedologic classification system. Histosols constitute one of the 10 orders of the hierarchical system that was developed from 1951 to 1974. (It was published as Soil Taxonomy, A Basic System of Soil Classification for Making and Interpreting Soil Survey, USDA Agriculture Handbook 436, 1975.) Histosols, unlike other soils, developed primarily from organic parent material and are saturated with water unless they are artificially drained. They are characterized by low bulk densities and are subject to large degrees of subsidence when drained; therefore, they present unique problems for use and management. The formation of Histosols, the differentiae used in classification, and the properties identified that affect engineering use are discussed.