Pachic (subgroup) (Figure 79).
Pachic (subgroup).—A taxonomic term used at the subgroup level (an extragrade) for soils with a mollic, melanic, or umbric epipedon that is 50 cm or more thick or, in some cold soils, 40 cm or more thick. These soils commonly are in landscape positions that are fairly stable and have well developed subsoil horizons, such as argillic or calcic horizons. The thick epipedon is thought to be the result of factors causing relatively deep natural incorporation of organic matter into the subsoil rather than the incremental accumulation of fresh sediment to the surface layer. See Cumulic subgroup.
Figure 79.—Soil profile and landscape of Dolason soil (fine-loamy, mixed, superactive, mesic Pachic Humixerept). The Dolason series consists of very deep, well drained soils formed in colluvium and residuum derived from siltstone, mudstone, and sandstone. Dolason soils are on mountains and have slopes of 9 to 75 percent. Elevations are 153 to 1032 meters (0 to 3390 feet). The umbric epipedon ranges from 50 to 100 centimeters thick. This soil is used for livestock grazing, recreation, wildlife habitat, and watershed.
Pachic (subgroup) (Figure 79).
Pachic (subgroup).—A taxonomic term used at the subgroup level (an extragrade) for soils with a mollic, melanic, or umbric epipedon that is 50 cm or more thick or, in some cold soils, 40 cm or more thick. These soils commonly are in landscape positions that are fairly stable and have well developed subsoil horizons, such as argillic or calcic horizons. The thick epipedon is thought to be the result of factors causing relatively deep natural incorporation of organic matter into the subsoil rather than the incremental accumulation of fresh sediment to the surface layer. See Cumulic subgroup.
Figure 79.—Soil profile and landscape of Dolason soil (fine-loamy, mixed, superactive, mesic Pachic Humixerept). The Dolason series consists of very deep, well drained soils formed in colluvium and residuum derived from siltstone, mudstone, and sandstone. Dolason soils are on mountains and have slopes of 9 to 75 percent. Elevations are 153 to 1032 meters (0 to 3390 feet). The umbric epipedon ranges from 50 to 100 centimeters thick. This soil is used for livestock grazing, recreation, wildlife habitat, and watershed.