LOCATION HOPE COEstablished Series
TAXONOMIC CLASS: Fine-silty, carbonatic, mesic Typic Calcigypsids
TYPICAL PEDON: Hope silty clay loam, on a west facing, 4 percent slope in broad alluvial flat at an elevation of 5,340 feet. (Colors are for dry soil unless otherwise noted.) When described on July 17, 1998 the soil was dry. The surface is covered by 1 percent gravel.
A--0 to 3 inches; light yellowish brown (10YR 6/4) silty clay loam, brown (10YR 5/3) moist; moderate very fine granular structure; soft, very friable, slightly sticky and slightly plastic; 3 percent gypsum; 20 percent calcium carbonate equivalent; violently effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary.
Bw--3 to 10 inches; light yellowish brown (10YR 6/4) silty clay loam, brown (10YR 5/3) moist; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and few fine roots throughout; few very fine discontinuous tubular pores; 3 percent gypsum; 20 percent calcium carbonate; 10 percent parachanners; violently effervescent; moderately alkaline (pH 8.2); clear smooth boundary.
Bky1--10 to 19 inches; light yellowish brown (10YR 6/4) silty clay loam, brown (10YR 5/3) moist; weak fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine, few fine, and common medium roots throughout; few very fine discontinuous tubular pores; few fine cylindrical gypsum threads; 14 percent gypsum; 34 percent calcium carbonate equivalent; violently effervescent; moderately alkaline (pH 8.2); clear smooth boundary.
Bky2--19 to 40 inches; pale brown (10YR 6/3) silt loam, light olive brown (2.5Y 5/3) moist; massive; moderately hard, very friable, slightly sticky and slightly plastic; common very fine, few fine, and common medium roots throughout; few very fine discontinuous tubular pores; few fine cylindrical gypsum threads and few medium rounded nests of gypsum throughout; 14 percent gypsum; 29 percent calcium carbonate equivalent; violently effervescent; moderately alkaline (pH 8.0); clear smooth boundary.
Bky3--40 to 58 inches; pale brown (10YR 6/3) gypsiferous silt loam, olive brown (2.5Y 4/3) moist; massive; moderately hard, very friable, slightly sticky and slightly plastic; common very fine and medium roots throughout; few very fine discontinuous tubular pores; few fine cylindrical gypsum threads and few medium rounded nests of gypsum throughout; 18 percent gypsum; 31 percent calcium carbonate equivalent; violently effervescent; moderately alkaline (pH 8.0); clear smooth boundary.
Bky4--58 to 80 inches; pale brown (10YR 6/3) silty clay loam, olive brown (2.5Y 4/3) moist; massive; moderately hard, very friable, slightly sticky and slightly plastic; common very fine and medium roots throughout; few very fine discontinuous tubular pores; few fine cylindrical gypsum threads and few medium rounded nests of gypsum throughout; 9 percent gypsum; 28 percent calcium carbonate equivalent; violently effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Montezuma County, Colorado; about 6 miles south of Towaoc; located about 900 feet west and 400 feet north of the southeast corner of sec. 10, T. 33 N., R. 18W.; Sentinel Peak SE, Colorado, USGS quad; lat. 37 degrees 6 minutes 48 seconds N. and long. 108 degrees 47 minutes 42 seconds W., NAD 27
RANGE IN CHARACTERISTICS:
Soil moisture: Typic aridic moisture regime
Mean annual soil temperature: 54 to 58 degrees F
Depth to gypsum accumulations: 5 to 20 inches
Particle-size control section (weighted average):
Clay content: 20 to 35 percent
Rock fragments: 0 to 2 percent
A horizon: (Thickness 2-6 inches)
Hue: 10 YR
Value: 5 or 6 dry or moist
Chroma: 3 to 5
Texture: silty clay loam
Clay content: 27 to 35 percent
Rock fragments: 0 to 5, mainly gravel
Calcium carbonate equivalent: 10 to 25 percent
EC (mmhos/cm): 0 to 2
Gypsum: 1 to 5 percent
SAR: 0 to 3
Reaction: moderately alkaline
Bw horizon: (Thickness 3-10 inches)
Hue: 10YR
Value: 5 or 6 dry or moist
Chroma: 3 or 4
Texture: silty clay loam, silt loam or loam
Clay content: 20 to 35 percent
Rock fragments: 0 to 2 percent
Pararock fragments: 0 to 15 percent
Calcium carbonate equivalent: 10 to 25 percent
EC (mmhos/cm): 0 to 2
Gypsum: 1 to 5 percent
SAR: 0 to 3
Reaction: moderately alkaline
Bky horizon: (Thickness 20-80 inches)
Hue: 10YR or 2.5Y
Value: 4 to 6 dry or moist
Chroma: 3 or 4
Texture: silty clay loam, silt loam or loam (some layers may be gypsiferous)
Rock fragments: 0 to 2 percent
Pararock fragments: 0 to 15 percent
Calcium carbonate equivalent: 20 to 35 percent
EC (mmhos/cm): 2 to 4
Gypsum: 5 to 25 percent
SAR: 0 to 3
Reaction: moderately alkaline
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Parent material: alluvium and slope alluvium derived from Mancos Shale
Landform: alluvial flats
Slopes: 1 to 6 percent
Elevation: 4,700 to 5,700 feet
Mean annual temperature: 52 to 56 degrees F
Mean annual precipitation: 7 to 10 inches
Precipitation pattern: Uniform with slight dip in May and June and slight increase in July and August.
Frost-free period: 135 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Persayo, Cornmeal, and Cowboy series. The Persayo soils are shallow and are on hills. The Cornmeal soils have a natric horizon and are on similar positions. The Cowboy soils have higher clay content and are in drainageways.
DRAINAGE AND PERMEABILITY: Well drained, medium runoff, moderately slow permeability.
USE AND VEGETATION: Rangeland. Native vegetation is alkali sacaton, galleta, and shadscale.
DISTRIBUTION AND EXTENT: Montezuma County, Colorado, Ute Mountain Indian Reservation; MLRA 35; small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona.
SERIES ESTABLISHED: Montezuma County, Colorado, Ute Mountain Area, Colorado and New Mexico, 2005.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Series control section: The zone from 0 to 79 inches.
Particle-size control section: The zone from 10 to 40 inches. (Bky1, Bky2 horizons)
Ochric epipedon: The zone from 0 to 3 inches. (A horizon)
Gypsic horizon: The zone from 10 to 80 inches. (Bky1, Bky2, Bky3, Bky4 horizons)
Calcic Horizon: The zone from 10 to 19 inches. (Bky1)
The assignment of the cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.
ADDITIONAL DATA: Calcium carbonate equivalence was determined using a field calcimeter. Gypsum content was determined using a HACH kit. EC was determined using a portable conductivity meter from a saturated extract.
Classified according to Keys to Soil Taxonomy Ninth Edition, 2003