LOCATION SIGNALHILL CO
Established Series
Rev. CRP/JCK
04/2019
SIGNALHILL SERIES
The Signalhill series consists of moderately deep, well drained soils that formed in slope alluvium, colluvium or slide deposits over residuum. These soils are on structural benches, dipslopes, fan remnants, escarpments, scarp slopes and landslides. Slopes are 3 to 65 percent. Mean annual precipitation is about 356 mm, and mean annual air temperature is about 8.3 degrees C.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Aridic Haplustalfs
TYPICAL PEDON: Signalhill loam, on a 5 percent slope in native rangeland at an elevation of 2,218 meters (colors are for dry soil unless otherwise noted).
A--0 to 12 cm; dark grayish brown (10YR 4/2) gravelly fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine, fine, medium, and coarse roots; 15 percent gravel and 10 percent cobbles; neutral (pH 7.2); clear wavy boundary. (5 to 13 cm thick)
Bt1--12 to 32 cm; brown (7.5YR 5/3) very gravelly sandy clay loam, brown (7.5YR 4/3) moist; weak coarse subangular blocky structure parting to weak fine and medium subangular blocky; slightly hard, friable, moderately sticky and moderately plastic; many fine and very fine, and common medium and coarse roots; few fine dendritic tubular pores; 65 percent distinct clay films on all ped faces; 25 percent gravel and 12 percent cobbles; neutral (pH 7.0); clear wavy boundary.
Bt2--32 to 56 cm; reddish brown (5YR 5/4) very gravelly sandy clay loam, reddish brown (5YR 4/4) moist; weak medium and coarse subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common very fine, fine, medium and coarse roots; 55 percent distinct clay films on all ped faces; 35 percent gravel and 15 percent cobbles; slightly alkaline (pH 7.6); clear wavy boundary. (Combined thickness of Bt horizons is 46 to 78 cm)
R--56 to 152 cm; hard sandstone bedrock.
TYPE LOCATION: Montrose County, Colorado; about 1 kilometer North and 488 kilometers West of the southeast corner of section 18 T 49N, R 7W; USGS Grizzly Ridge Topographic Quadrangle; 38 degrees, 30 minutes, 50.9 seconds N, 107 degrees, 42 minutes, 6.2 seconds W.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 8 to 11 degrees C
Particle-size control section (weighted average):
Clay content - 20 to 35 percent
Rock fragment content - 35 to 75 percent gravel, cobbles and stones
A horizons
Hue: 7.5YR or 10YR
Value: 4 or 5 dry; 3 or 4 moist
Chroma: 2, 3 or 4
Texture: fine sandy loam or sandy loam
Clay content: 12 to 18 percent
Rock fragments: 10 to 35 percent; 10 to 25 percent gravel, 5 to 20 percent cobbles, 0 to 5 percent stones
Reaction: pH 6.8 to 7.4
Bt horizons
Hue: 5YR, 7.5YR or 10YR
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 3 or 4
Texture: sandy loam or sandy clay loam
Clay content: 18 to 35 percent
Rock fragments: 35 to 75 percent; 25 to 50 percent gravel, 5 to 40 percent cobbles, 0 to 15 percent stones
Reaction: pH 7.0 to 7.8
COMPETING SERIES:
Casto (AZ) - are very deep; have secondary calcium carbonate accumulation
Espiritu (NM) - are very deep; have secondary calcium carbonate accumulation
Snavee (WY) - are very deep; have secondary calcium carbonate accumulation
Wauquie (NM) - are very deep; have secondary calcium carbonate accumulation
Wetoe (CO) - are very deep
GEOGRAPHIC SETTING:
Landform - structural benches, dipslopes, fan remnants, escarpments, scarp slopes and landslides
Elevation - 1,829 to 2,286 meters
Slope - 3 to 65 percent
Parent material - slope alluvium, colluvium or slide deposits over residuum
Mean annual precipitation - 305 to 406 mm
Mean annual air temperature - 7.2 to 10.0 degrees C
Frost-free period - 105 to 155 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Signalhill soils are used for livestock grazing and wildlife habitat. Native vegetation is mainly twoneedle pinyon, western wheatgrass, Sandberg bluegrass, Wyoming big sagebrush, Indian ricegrass and Utah juniper.
DISTRIBUTION AND EXTENT: Signalhill soils are of small extent in southwestern Colorado. MLRA 36 and 48A.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Montrose County, Colorado - Ridgway Area, Colorado, Parts of Delta, Gunnison, Montrose, and Ouray Counties, 2019.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from 0 to 12 cm (A horizon)
Argillic horizon - from 12 to 56 cm (Bt1 and Bt2 horizons)
Lithic contact - at 56 cm (R horizon)
Particle-size control section - from 12 to 56 cm (Bt1 and Bt2 horizons)
Signalhill soils have a mesic temperature regime and an ustic moisture regime bordering on aridic.
National Cooperative Soil Survey
U.S.A.