LOCATION EGUAJE COEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, mesic Calcidic Argiustolls
TYPICAL PEDON: Eguaje cobbly clay loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 5 inches; dark grayish brown (10YR 4/2) cobbly clay loam, very dark brown (10YR 2/2) moist; moderate medium and fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; 10 percent pebbles, 10 percent cobbles, 6 percent stones; neutral (pH 7.0); clear smooth boundary. (3 to 7 inches)
Bt-- 5 to 14 inches; brown (10YR 4/3) very cobbly clay loam; dark brown (10YR 3/3) moist; moderate medium and fine subangular blocky structure; hard, firm, sticky and plastic; common distinct clay films on ped faces; 20 percent pebbles, 20 percent cobbles; neutral (pH 7.3); abrupt smooth boundary. (7 to 12 inches)
Btk1-- 14 to 19 inches; brown (10YR 5/3) very gravelly clay, brown (10YR 4/3) moist; moderate fine subangular blocky structure; hard, firm, sticky and plastic; few distinct clay films on ped faces; 30 percent pebbles; 10 percent cobbles, 5 percent stones; common fine masses of calcium carbonate; 17 percent calcium carbonate equivalent; violently effervescent; moderately alkaline (pH 8.0); gradual smooth boundary. (3 to 9 inches)
Btk2-- 19 to 28 inches; pale brown (10YR 6/3) very gravelly clay loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; slightly hard, firm, sticky and plastic; 35 percent pebbles, 20 percent cobbles; common fine masses of calcium carbonate; 34 percent calcium carbonate equivalent; violently effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (7 to 12 inches)
Bk--28 to 60 inches; very pale brown (10YR 7/3) very cobbly clay loam, brown (10YR 4/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; 25 percent pebbles, 30 percent cobbles; 40 percent calcium carbonate equivalent; violently effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Las Animas County, Colorado; approximately 8 miles southeast of Kim, Colorado on the Tecolote Mesa; about 500 feet west and 1,050 feet south of the northeast corner of Sec. 20, T. 33 S., R. 52 W.; Kim South USGS quadrangle; Latitude 37 degrees, 09 minutes, 33 seconds north; Longitude 103 degrees, 15 minutes, 54 seconds west.
RANGE IN CHARACTERISTICS:
Soil moisture: Ustic moisture regime bordering on aridic. Moist in some part April through August. Driest December though February.
Mean annual soil temperature: 48 to 52 degrees F.
Mean summer soil temperature: 68 to 72 degrees F.
Thickness of the mollic epipedon: 7 to 20 inches thick.
Depth to secondary calcium carbonate: 10 to 19 inches
Depth to the base of the argillic horizon: 20 to 40 inches.
Depth to the calcic horizon: 10 to 25 inches.
Particle size control section: (weighted average)
Clay content: 35 to 45 percent
Rock fragments content: 35 to 70 percent, dominantly gravel and cobbles.
The surface is commonly covered with 5 to 20 percent stones.
A horizon
Hue: 7.5YR to 2.5Y
Value: 3 or 4 dry, 2 or 3 moist
Chroma: 2 or 3
Rock fragment content: 15 to 45 percent
Reaction: neutral or slightly alkaline.
Bt horizon
Hue: 7.5YR to 2.5Y
Value: 3 to 5 dry, 2 to 4 moist
Chroma: 2 or 3
Texture: very cobbly clay loam or very cobbly clay
Clay content: 35 to 50 percent.
Rock fragment content: 35 to 60 percent
Reaction: neutral or slightly alkaline.
Btk horizon
Hue: 7.5YR to 2.5Y
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 or 4
Texture: very gravelly clay loam, very cobbly clay loam, very gravelly clay
Clay content: 35 to 50 percent
Rock fragment content: 35 to 70 percent
Calcium carbonate equivalent: 15 to 35 percent, increasing with depth
Bk horizon
Hue: 7.5YR to 2.5Y
Value: 5 to 7 moist, 4 to 6 moist
Chroma: 3 to 6
Texture: very cobbly clay loam or very cobbly loam
Rock fragment content: 35 to 70 percent
Reaction: moderately alkaline or strongly alkaline
Calcium carbonate equivalent: 20 to 45 percent
COMPETING SERIES: There are no competing series. A closely similar soil is the
Delenbaw (AZ) series.
Delenbaw soils: do not have a calcic horizon and have hue of 2.5YR or 5YR in the argillic horizon.
GEOGRAPHIC SETTING:
Parent material: colluvium and residuum from basalt
Landform: undulating basalt capped mesas and lava plateaus.
Slopes: 1 to 15 percent
Elevation: 5,500 to 7,000 feet
Mean annual precipitation: 15 to 17 inches
Mean annual temperature: 50 to 53 degrees F.
The frost-free period: 125 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Apache, Ayon, Demayo, and Torreon soils.
Apache and
Demayo soils: have a lithic contact at depths of less than 20 inches and are on summits and shoulders.
Ayon soils: do not have an argillic horizon and are on backslopes and summits
Torreon soils: average less than 35 percent rock fragments in the particle size control section and are on nearly level areas.
DRAINAGE AND PERMEABILITY: Well drained; runoff is medium on 1 to 5 percent slopes and high on 5 to 15 percent slopes; permeability is moderately slow.
USE AND VEGETATION: Eguaje soils are used primarily for livestock grazing and wildlife habitat. Vegetation is mainly blue grama, western wheatgrass, sideoats grama, little and big bluestems, and small amounts of shrubs.
DISTRIBUTION AND EXTENT: Southeastern Colorado. LRR G, MLRA 70. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES PROPOSED: Las Animas County, Colorado, 1989. The name is pronounced E-gwa-hay. The name is taken from a major drainage in the area.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Particle size control section: 5 to 25 inches. (Bt, Btk1 and parts of the Btk2 horizons)
Mollic epipedon: 0 to 14 inches. (A and Bt horizons)
Argillic horizon: 5 to 28 inches. ( Bt, Btk1 and Btk2 horizons)
Calcic horizon: 14 to 60 inches. (Btk1, Btk2, Bk horizons)
Taxonomic Version: Second Edition, 1999
ADDITIONAL DATA: Laboratory pedon number: S88CO-071-002.