LOCATION SAMALA CO

Established Series
Rev. MJB/CRP/JCK
04/2019

SAMALA SERIES

The Samala series consists of very deep, well drained soils that formed in slope alluvium derived from mixed sources. Samala soils are on cuesta dip slopes, fan remnants, and structural benches. Slopes are 0 to 15 percent. Mean annual precipitation is about 279 mm, and mean annual air temperature is about 11 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Ustic Calciargids

TYPICAL PEDON: Samala gravelly sandy loam, 3 percent slope at an elevation of 1,972 meters. The surface is covered by 35 percent gravel and 3 percent cobbles. (Colors are for dry soil unless otherwise noted.)

A--0 to 12 cm; light brown (7.5YR 6/4) very gravelly sandy loam, brown (7.5YR 4/3) moist; weak fine granular structure; soft, friable, slightly sticky and slightly plastic; common fine and medium roots; 30 percent gravel and 10 percent cobbles; slightly effervescent; slightly alkaline (pH 7.6); abrupt wavy boundary. (10 to 15 cm thick)

Btk1--12 to 31 cm; pink (7.5YR 7/3) very cobbly sandy clay loam, brown (7.5YR 4/4) moist; weak medium subangular blocky structure; slightly hard, firm, moderately sticky and moderately plastic; common fine and medium roots; 5 percent faint clay films on faces of peds; 20 percent calcium carbonate masses in the matrix and 20 percent carbonate coats on rock fragments; 25 percent gravel and 15 percent cobbles; strongly effervescent; moderately alkaline (pH 8.0); clear wavy boundary.

Btk2--31 to 53 cm; pink (7.5YR 8/3) very gravelly sandy loam, pink (7.5YR 7/4) moist; weak medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common fine roots; 5 percent distinct clay films on faces of peds; 25 percent calcium carbonate masses in the matrix and 25 percent carbonate coats on rock fragments; 30 percent gravel and 10 percent cobbles; violently effervescent; moderately alkaline (pH 8.2); clear wavy boundary.

Btk3--53 to 81 cm; pink (7.5YR 8/3) very gravelly sandy loam, pink (7.5YR 7/4) moist; weak medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few fine roots; 5 percent faint clay films on faces of peds; 30 percent calcium carbonate masses in the matrix; 30 percent gravel and 10 percent cobbles; violently effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (combined thickness of the Btk horizons is 30 to 100 cm)

Bk--81 to 152 cm; pinkish white (7.5YR 8/2) very cobbly sandy loam, pink (7.5YR 7/3) moist; weak fine and medium subangular blocky structure; hard, firm, moderately sticky and slightly plastic; 35 percent calcium carbonate masses in the matrix; 25 percent gravel and 15 percent cobbles; violently effervescent; moderately alkaline (pH 8.2).

TYPE LOCATION: Montrose County, Colorado; located about 640 meters east and 610 meters south of the northwest corner of sec. 20, T. 48 N., R. 9 W.; Montrose West USGS quad; lat. 38 degrees 24 minutes 6 seconds N. and long. 107 degrees 52 minutes 55 seconds W.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 10 to 13 degrees C
Depth to secondary calcium carbonate - 10 to 15 cm
Depth to argillic base - 70 to 100 cm
Particle-size control section (weighted average):
Clay content: 18 to 35 percent
Rock fragments: 35 to 70 percent - 35 to 60 percent gravel, 10 to 30 percent cobbles

A horizons
Hue: 7.5YR or 10YR
Value: 4, 5 or 6 dry or moist
Chroma: 3 or 4 dry or moist
Texture: sandy loam, loam or sandy clay loam
Clay content: 12 to 25 percent
Rock fragments: 15 to 65 percent - 15 to 65 percent gravel, 0 to 15 percent cobbles
Reaction: pH 7.4 to 8.2

Btk horizons
Hue: 7.5YR or 10YR
Value: 6, 7 or 8 dry, 4, 5, 6 or 7 moist
Chroma: 3 or 4 dry or moist
Texture: sandy loam or sandy clay loam
Clay content: 18 to 35 percent
Rock fragments: 35 to 70 percent - 35 to 60 percent gravel, 10 to 30 percent cobbles
Calcium carbonate equivalent: 15 to 40 percent
Reaction: pH 8.0 to 8.4

Bk horizons:
Hue: 7.5YR or 10YR
Value: 6, 7 or 8 dry or moist
Chroma: 2, 3 or 4 dry or moist
Texture: sandy loam or sandy clay loam
Clay content: 12 to 25 percent
Rock fragments: 35 to 70 percent - 35 to 60 percent gravel, 10 to 30 percent cobbles
Calcium carbonate equivalent: 15 to 40 percent
Sodium adsorption ratio: 0 to 4
Reaction: pH 8.0 to 8.6

COMPETING SERIES:
Larim (WY) - have a lithologic discontinuity; have an argillic base less than 70 cm deep
Musofare (NM) - are moderately deep to a lithic contact
Sedillo (NM) - do not have secondary calcium carbonate above 15 cm; have an argillic base less than 70 cm deep

GEOGRAPHIC SETTING:
Elevation - 1,585 to 2,134 meters
Landform - dip slopes, fan remnants and structural benches
Slope - 0 to 15 percent
Parent material - slope alluvium
Mean annual air temperature - 9 to 12 degrees C
Mean annual precipitation - 203 to 305 mm
Precipitation pattern - even yearly distribution with slight increase in spring and significant increase in late summer
Frost-free period - 120 to 165 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Barx and Barboncito soils.

DRAINAGE AND PERMEABILITY: Well drained, moderate permeability.

USE AND VEGETATION: Samala soils are used mainly for rangeland. Native vegetation is James' galleta, Indian ricegrass, Wyoming big sagebrush, fourwing saltbush, squirreltail and scattered Utah juniper.

DISTRIBUTION AND EXTENT: Samala soils are of minor extent in western Colorado. MLRA 36.

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 81 cm (Btk1, Btk2, and Btk3 horizons)
Calcic horizon from - 12 to 152 cm (Btk1, Btk2, Btk3 and Bk horizons)
Particle-size control section from - 12 to 62 cm (Btk1, Btk2, and part of Btk3 horizon)

Samala soils have a mesic temperature regime and an aridic moisture regime bordering on ustic.

National Cooperative Soil Survey
U.S.A.