LOCATION RICOT COEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Typic Argiustolls
TYPICAL PEDON: Ricot loam in grassland. (Colors are for dry soil unless otherwise noted.)
A--0 to 8 inches; brown (7.5YR 4/2) loam, dark brown (7.5YR 3/2) moist; strong fine granular structure; soft, very friable, slightly sticky and slightly plastic; neutral (pH 7.2); clear smooth boundary. (4 to 10 inches thick)
BAt--8 to 12 inches; brown (7.5YR 5/3) loam, dark brown (7.5YR 3/2) moist; moderate fine subangular blocky structure parting to coarse granular; slightly hard, very friable, slightly sticky and slightly plastic; few faint clay films on faces of peds and in pores; neutral (pH 7.2); clear smooth boundary. (3 to 5 inches thick)
Bt--12 to 16 inches; reddish brown (5YR 5/3) clay loam, reddish brown (5YR 4/3) moist; moderate fine subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; common distinct clay films on faces of peds and in pores; a thin stone line of gravel and cobbles occurs at the lower margin of this horizon; neutral (pH 7.0); clear smooth boundary. (4 to 10 inches thick)
2Bt1--16 to 28 inches; reddish brown (5YR 5/4) clay, reddish brown (5YR 4/4) moist; weak coarse prismatic structure parting to moderate coarse angular blocky; very hard, friable, moderately sticky and moderately plastic; many distinct clay films on faces of peds and in pores; 2 percent igneous gravel, 5 percent cobbles and 5 percent stones; neutral (pH 7.0 ); clear wavy boundary. (5 to 25 inches thick)
2Bt2--28 to 34 inches; reddish brown (5YR 5/4) clay, reddish brown (5YR 4/4) moist; weak coarse prismatic structure parting to moderate coarse angular blocky; very hard, friable, moderately sticky and moderately plastic; many distinct clay films on faces of peds and in pores; 2 percent igneous gravel; 5 percent cobbles and 5 percent stones; slightly effervescent; moderately alkaline (pH 7.9); gradual wavy boundary. (0 to 24 inches thick)
2Bk1--34 to 38 inches; reddish brown (5YR 5/4) clay, reddish brown (5YR 4/4) moist; weak medium angular and subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; few distinct clay films on faces of peds and in pores; 2 percent igneous gravel; 5 percent cobbles and 5 percent stones; many fine masses, seams, filaments, and threads of calcium carbonate; violently effervescent; moderately alkaline (pH 8.0); gradual wavy boundary. (3 to 6 inches thick)
2Bk2--38 to 60 inches; light reddish brown (5YR 6/4) stony clay loam, reddish brown (5YR 5/4) moist; massive; extremely hard, very firm, moderately sticky and moderately plastic; 5 percent igneous gravel; 10 percent cobbles and 15 percent stones; many fine masses, seams, filaments, and threads of calcium carbonate; violently effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Montezuma County, Colorado; about 1,100 feet south and 240 feet east of the northwest corner of sec. 11, T. 36 N., R. 13 W.; Millwood USGS quad; lat. 37 degrees 23 minutes 48 seconds N. and long. 108 degrees 15 minutes 36 seconds W., NAD 27
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 45 to 47 degrees F
Surface rock fragments: 0 to 5 percent igneous gravel cobble or stones
Depth to lithologic discontinuity: 15 to 30 inches
Depth to secondary calcium carbonate: 12 to 50 inches
Depth to the base of the argillic horizon: 17 to 50 inches
Thickness of the mollic epipedon: 10 to 16 inches
Particle-size control section: 35 to 50 percent clay
A horizon:
Hue: 5YR or 7.5YR
Value: 3 to 5 dry, 2 or 3 moist
Chroma: 1 to 3 dry or moist
Rock fragments: 0 to 5 percent
Reaction: neutral or slightly alkaline
Bt horizon:
Hue: 5YR or 7.5YR
Value: 5 to 7 dry, 3 to 6 moist
Chroma: 2 to 6 dry or moist
Texture: clay or clay loam
Rock fragments: 0 to 5 percent
Calcium carbonate equivalent: 0 to 5 percent
Reaction: neutral to moderately alkaline
2B horizon:
Hue: 5YR or 7.5YR
Value: 5 to 7 dry, 3 to 6 moist
Chroma: 2 to 6 dry or moist
Texture: clay or clay loam
Rock fragments: 10 to 35 percent, mostly cobbles and stones
Calcium carbonate equivalent: 0 to 10 percent
Reaction: neutral to moderately alkaline
COMPETING SERIES: These are the Absarokee, Acree, Bearpaw, Brolliar, Delson, Herm, Morapos, Nortez, Peninsula, Pramiss, Reget, Tamaneen, Tomasaki, Tukuhnik, and Work series.
Absarokee, Brolliar, Nortez, Pramiss, and Reget soils have either a lithic or a paralithic contact above a depth of 40 inches.
Bearpaw, and Work soils have hues of 10YR or yellower.
Delson and Herm soils are noncalcareous throughout and lack consistent horizons of secondary carbonate accumulation.
Acree soils lack stones in the lower part of the solum.
Morapos and Tamaneen soils are yellower than 5YR in the control section.
Peninsula soils have a calcic horizon.
Tukuhnik soils have a lithic contact at a depth of 40 to 60 inches.
Tomasaki soils do not have accumulations of secondary calcium carbonates.
GEOGRAPHIC SETTING:
Parent material: eolian material overlying outwash derived from mixed sources
Landform: hills, mountains, and mesas
Slopes: 1 to 12 percent
Elevation: 7,100 to 8,500 feet
Mean annual temperature: 43 to 47 degrees F
Mean annual precipitation: 15 to 20 inches
Precipitation is fairly evenly distributed throughout the year with July and August being slightly wetter and June being slightly dryer.
Frost-free period: 80 to 100 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Granath and Hesperus series. Granath soils have fine-silty solums and are formed entirely in eolian material on mesas and hills. Hesperus soils have thicker mollic epipedons and have less than 15 percent rock fragments above a depth of 40 inches in drainageways.
DRAINAGE AND PERMEABILITY: well drained, medium to very high runoff, slow permeability
USE AND VEGETATION: They are used principally as grazing land. Native vegetation is Gambel's oak, western wheat, native bluegrass, and Indian ricegrass.
DISTRIBUTION AND EXTENT: Southwest Colorado. LRR E, MLRA 48A. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Cortez Area, Colorado, Parts of Dolores and Montezuma Counties, 1997.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: The zone from 0 to 12 inches. (A and BAt)
Argillic horizon: The zone from 12 to 34 inches. (Bt, 2Bt1, 2Bt2)
Lithologic discontinuity: The zone from 16 to 60 inches. (2Bt1, 2Bt2, 2Bk1, 2Bk2)
Particle-size control section: The zone from 12 to 32 inches. (Bt, 2Bt1, 2Bt2)
Soil Taxonomy Second Edition, 1999.
These soils are borderline mesic-frigid. Future temperature studies are needed to resolve this issue.