LOCATION HERM CO+NM UT
Established Series
Rev. JPP-TWH-KLS
02/2018
HERM SERIES
The Herm series consists of very deep, well drained soils that formed in slope alluvium derived principally from interbedded sandstone and shale and in some pedons have eolian influence in the upper layers. Herm soils are on mountain slopes, hillslopes, and structural benches. Slopes range from 0 to 50 percent. The mean annual precipitation is about 508 mm and the mean annual temperature is about 4.4 degrees C.
TAXONOMIC CLASS: Fine, smectitic, frigid Typic Argiustolls
TYPICAL PEDON: Herm loam, on a west facing, simple, 5 percent slope in rangeland at an elevation of 2,469 meters. (Colors are for dry soil unless otherwise noted.) Described on October 1, 1986.
A--0 to 15 cm; dark grayish brown (10YR 4/2) loam, black (10YR 2/1) moist; moderate medium granular structure; soft, friable, slightly sticky and slightly plastic; common fine and few medium roots; few very fine pores; neutral (pH 6.8); clear smooth boundary. (8 to 25 cm thick)
AB--15 to 33 cm; dark brown (10YR 3/3) clay loam, very dark gray (10YR 3/1) moist; moderate medium subangular blocky structure parting to moderate medium granular; hard, firm, sticky and plastic; common fine and few medium roots; few very fine pores; neutral (pH 6.6); clear smooth boundary. (0 to 20 cm thick)
Bt1--33 to 43 cm; grayish brown (10YR 5/2) clay loam, dark grayish brown (10YR 4/2) moist; strong medium angular and subangular blocky structure; hard, firm, very sticky and very plastic; few distinct clay films on faces of peds; few fine and few medium roots; few very fine pores; neutral (pH 6.6); gradual wavy boundary.
Bt2--43 to 114 cm; brown (10YR 5/3) clay loam, brown (10YR 4/3) moist; strong medium angular and subangular blocky structure; very hard, very firm, very sticky and very plastic; many prominent clay films on faces of peds; common very fine and few fine roots; neutral (pH 6.6); gradual wavy boundary. (combined thickness of the Bt horizons is 51 to 127 cm)
BC--114 to 152 cm; grayish brown (10YR 5/2) clay loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; hard, firm, sticky and plastic; 5 percent gravel, 9 percent cobble; neutral (pH 7.0).
TYPE LOCATION: Montezuma County, Colorado; about 10 kilometers northeast of Mancos, Colorado, along Forest Service Road 566, about 91 meters north of the road; located about 335 meters south and 518 meters east of the northwest corner of Sec. 7, T. 36 N., R. 12 W.; Rampart Hills USGS quad.; Lat. 37 degrees, 23 minutes, 51 seconds N., and Long. 108 degrees, 13 minutes, 19 seconds W., NAD 27.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 5.0 to 7.8 degrees C.
Mean annual summer soil temperature: 10.0 to 12.8 degrees C. with an O horizon, and 15.0 to 17.2 degrees C. without an O horizon.
Thickness of the mollic epipedon: 25 to 41 cm
Depth to calcium carbonate: if present, 91 to 152 cm
Particle-size control section: 35 to 55 percent clay, 15 to 50 percent silt, 10 to 45 percent sand, and 0 to 30 percent rock fragments, but typically less than 5 percent. They consist of pebbles, cobble and stones mostly derived from sandstone, but have diorite fragments in some pedons.
A horizon
Hue: 5YR to 10YR
Value: 3 to 5 dry, 2 or 3 moist
Chroma: 1 to 3, dry or moist
Texture: loam, clay loam
Clay content: 15 to 35 percent
Rock fragments: 0 to 30 percent, mostly stone and cobble of sandstone and diorite composition
Reaction (pH): 6.1 to 7.8
BA or AB horizon (where present)
Value: 3 to 5 dry, 2 or 3 moist
Chroma: 2 or 3 dry or moist
Texture: silty clay loam, silt loam, or loam
Clay content: 15 to 35 percent
Rock fragments: 0 to 30 percent, sandstone and shale gravel
Reaction (pH): 6.1 to 7.8
Bt1 horizon
Hue: 5YR to 10YR
Value: 4 to 6 dry, 2 to 4 moist
Chroma: 2 to 4, dry or moist
Texture: clay loam, clay, silty clay loam
Clay content: 35 to 55 percent
Rock fragments: 0 to 15 percent, sandstone and shale gravel
Reaction (pH): 6.1 to 7.8
Bt2 horizon
Hue: 10YR or 2.5Y
Value: 5 to 7 dry, 4 to 6 moist
Chroma: 3 to 6, dry or moist
Texture: clay loam, clay, silty clay loam
Clay content: 35 to 55 percent
Rock fragments: 0 to 15 percent, sandstone and shale gravel
Reaction (pH): 6.1 to 7.3
BC horizon (a Bk or C horizon in some pedons)
Hue: 10YR or 2.5Y
Value: 5 to 7 dry, 4 to 7 moist
Chroma: 2 to 6, dry or moist
Texture: clay loam, clay, silty clay loam
Clay content: 35 to 45 percent
Rock fragments: 0 to 30 percent, sandstone and shale gravel and cobble
Calcium carbonate equivalent: 0 to 5 percent
Reaction (pH): 6.6 to 8.4
COMPETING SERIES:
Absarokee (MT) - are moderately deep to paralithic contact
Acree (CO) - have diagnostic horizons of calcium carbonate accumulation
Barela (NM) - are deep to lithic contact
Capillo (NM) - are deep to paralithic contact
Dandrea (AZ) - are moderately deep to paralithic contact
Delson (CO) - have hues of 7.5YR and redder in the lower part of the Bt horizon
Ekah (MT) - have horizons of calcium carbonate accumulation
Morapos (C) - have horizons of calcium carbonate accumulation
Moreno (NM) - have hues of 7.5YR and redder in the lower part of the Bt horizon
Nortez (CO) - are moderately deep to lithic contact
Pramiss (CO) - are moderately deep to paralithic contact
Ricot (CO) - have a lithologic discontinuity
Tamaneen (MT) - have a diagnostic calcic horizon
Tukuhnik (UT) - are deep to lithic contact
Work (MT) - have horizons of calcium carbonate accumulation
Zau (CO) - are moderately deep to paralithic contact
GEOGRAPHIC SETTING:
Landform - mountain slopes, hillslopes, and structural benches
Elevation - 2,070 to 2,900 meters
Slopes - 0 to 50 percent
Parent material - slope alluvium derived from shale and sandstone; some pedons are influenced by eolian materials in the upper horizons
Mean annual air temperature - 3.3 to 7.2 degrees C.
Mean annual precipitation - 356 to 635 mm
Precipitation pattern - July and August are the wettest months, receiving slightly more precipitation than other months. May and June are the driest months, receiving the least precipitation, however the soils are still moist from snowmelt through mid-June.
Frost-free period - 75 to 115 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; slow permeability.
USE AND VEGETATION: These soils are used for timber production, livestock grazing, and wildlife habitat. Native vegetation consists of, Gambel oak, snowberry, Arizona fescue, mountain muhly, mountain brome, bluegrass, junegrass, and forbs; with or without an overstory of ponderosa pine.
DISTRIBUTION AND EXTENT: Southwestern Colorado, southeastern Utah and northern New Mexico. LRR D, E; MLRA 36, 48A. This series is of moderate extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Paonia Area, Colorado, 1976.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: 0 to 33 cm (A and AB horizons)
Argillic horizon: 33 to 114 cm (Bt1 and Bt2 horizons)
Particle-size control section: 33 to 83 cm (Bt1 and part of the Bt2 horizon)
Herm soils have a frigid temperature regime and are in an ustic soil moisture regime with a typic subclass.
National Cooperative Soil Survey
U.S.A.