LOCATION HUMBARSPRINGS COEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Aridic Calciustolls
TYPICAL PEDON: Humbarsprings gravelly loam - grassland. (Colors are for dry soil unless otherwise noted.)
A--0 to 7 inches; dark grayish brown (10YR 4/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; weak medium granular structure; slightly hard, friable, nonsticky and nonplastic; common fine roots; 5 percent calcium carbonate equivalent; strongly effervescent; 20 percent gravel and 5 percent cobbles; slightly alkaline (pH 7.8); clear wavy boundary. (7 to 10 inches thick.)
Bw--7 to 10 inches; brown (10YR 5/3) gravelly loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine roots; 5 percent calcium carbonate equivalent; violently effervescent; 20 percent gravel and 5 percent cobbles; moderately alkaline (pH 8.0); gradual wavy boundary. (3 to 6 inches thick.)
Bk1--10 to 22 inches; pale brown (10YR 6/3) gravelly sandy clay loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few fine roots; 15.0 percent calcium carbonate equivalent; common fine distinct carbonate masses; violently effervescent; 20 percent gravel and 5 percent cobbles; moderately alkaline (pH 8.4); abrupt wavy boundary. (10 to 14 inches thick.)
2Bk2--22 to 35 inches; light yellowish brown (10YR 6/4) gravelly sand, dark yellowish brown (10YR 4/4) moist; single grain; loose, loose, nonsticky and nonplastic; 20 percent calcium carbonate equivalent; common medium distinct carbonate masses; violently effervescent throughout; 16 percent gravel; moderately alkaline (pH 8.4); abrupt wavy boundary. (10 to 20 inches thick.)
2Bk3--35 to 60 inches; very pale brown (10YR 8/2) gravelly loamy fine sand, pale brown (10YR 6/3) moist; massive; soft, very friable, nonsticky and nonplastic; 35.0 percent calcium carbonate equivalent; violently effervescent; 25 percent gravel; strongly alkaline (pH 8.6).
TYPE LOCATION: Las Animas County, Colorado, approximately 1,250 feet east and 1,200 feet north of the southwest corner of section 6, T. 33 S., R. 51 W.; latitude 37 degrees 11 minutes 46 seconds N. and longitude 103 degrees 11 minutes 12 seconds W.
RANGE IN CHARACTERISTICS:
Soil Moisture: moist intermittently from April through August, driest period is December through February. Ustic moisture regime bordering on aridic
Mean annual soil temperature: 49 to 54 degrees F.
Mean summer soil temperature: 70 to 76 degrees F.
Thickness of the mollic epipedon: 7 to 16 inches
Depth to lithological discontinuity: 20 to 30 inches
Depth to carbonates: 0 to 7 inches
Particle size control section: (weighted average)
Clay content: 18 to 27 percent clay
Sand content: 45 to 65 percent
Rock fragment content: 20 to 35 percent
A Horizon:
Hue: 7.5YR or 10YR
Value: 3 to 5 dry, 2 or 3 moist
Chroma: 2 or 3
Reaction: slightly alkaline or moderately alkaline
Rock fragments: 15 to 35 percent
Bw and Bk1 Horizons:
Hue: 7.5YR or 10YR
Value: 4 to 6 dry, 3 to 5 moist
Chroma: 2 to 4
Texture of the fine earth fraction: loam or sandy clay loam
Clay content: 18 to 27 percent
Rock fragments: 15 to 45 percent, dominantly gravel.
Reaction: slightly alkaline or moderately alkaline
Calcium carbonate equivalent: 1 to 5 percent in the Bw, 5 to 15 percent in the Bk1
2Bk Horizons:
Hue: 7.5YR or 10YR
Value: 6 to 8 dry, 4 to 6 moist
Chroma: 2 to 4
Texture of the fine earth fraction: sand, fine sand, loamy fine sand, loamy sand
Clay content: 0 to 8 percent
Rock fragments: 5 to 45 percent, dominantly gravel
Reaction: moderately alkaline or strongly alkaline
Calcium carbonate equivalent: 15 to 40 percent
COMPETING SERIES: These are the
Graystone (WY),
Greenhope (WY),
Guy (NM),
Laird (CO) and
Sidney (NE) series.
Graystone soils: averages less than 15 percent rock fragments
Greenhope soils: do not have strongly contrasting 2Bk horizons.
Guy soils: depth to strongly contrasting 2C horizon is greater than 30 inches.
Laird soils: averages less than 15 percent rock fragments
Sidney soils: have a paralithic contact at depths of 40 to 60 inches.
GEOGRAPHIC SETTING:
Parent material: alluvium from mixed sources of the Ogallala and Dakota formations
Landform: fans and terraces bordering major drainage systems
Slopes: 3 to 12 percent
Elevations: 5,000 to 6,500 feet
Mean annual air temperature: 51 to 53 degrees F.
Mean annual precipitation: 14 to 16 inches
Wettest period: April through August
Driest period: December through February
Frost-free days: 125 to 155 days
GEOGRAPHICALLY ASSOCIATED SOILS:
These are the
Ayon,
Capulin and
Chicosa soils. Ayon and Chicosa soils average more than 35 percent rock fragments in the control section and are on fan remnants. Capulin soils average more than 18 percent clay in the control section and have an argillic horizon.
DRAINAGE AND PERMEABILITY: Well to somewhat excessively drained, medium runoff, moderately rapid to moderate permeability
USE AND VEGETATION: These soils are used as rangeland and as sources of sand and gravel. Native vegetation is mainly blue grama, sideoats grama, little bluestem and sand dropseed.
DISTRIBUTION AND EXTENT: Southeastern Colorado in the Aridic-ustic moisture regime; LRR G, MLRA 67. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado.
SERIES PROPOSED: Las Animas County, Colorado 1996
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: the zone form 0 to 7 inches. (A and Bw horizons)
Cambic horizon: the zone from 10 to 22 inches. (Bk horizon)
Calcic horizon: the zone from 22 to 60 inches.
Lithilogical discontinuity: 22 inches
Modified by Lee Neve in January 2002 to update the classification from the fine-loamy family to coarse-loamy.
Keys to Soil Taxonomy used: Eighth Edition, 1998