LOCATION CHICOSA COEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Aridic Calciustepts
TYPICAL PEDON: Chicosa gravelly loam, on a north facing, 12 percent slope in rangeland at an elevation of 6060 feet. (Colors are for dry soil unless otherwise noted.) When described on November 11, 1985 the soil was moist from 0 to 20 inches. The surface is covered by 15 percent gravel, 5 percent cobbles.
A--0 to 6 inches (0 to 15 cm); dark grayish brown (10YR 4/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; soft, friable, nonsticky and nonplastic; 15 percent gravel, 5 percent cobbles; slightly effervescent (3 percent calcium carbonate equivalent); slightly alkaline; clear smooth boundary. (4 to 6 inches thick)
Bw--6 to 20 inches (15 to 51 cm); light brown (7.5YR 6/4) very gravelly loam, strong brown (7.5YR 4/6) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; 40 percent gravel, 5 percent cobbles; strongly effervescent (7 percent calcium carbonate); moderately alkaline; abrupt smooth boundary. (10 to 15 inches thick)
2Bk--20 to 37 inches (51 to 94 cm); very pale brown (10YR 8/3) extremely gravelly sandy loam, pale brown (10YR 6/3) moist; massive; very hard, friable, nonsticky and nonplastic; common masses and filaments of lime; 55 percent gravel, 10 percent cobbles; strongly effervescent (18 percent calcium carbonate); moderately alkaline; gradual smooth boundary. (12 to 24 inches thick)
2C--37 to 72 inches (94 to 183 cm); brown (10YR 5/3) extremely gravelly loamy sand, brown (10YR 4/3) moist; massive; loose, loose, nonsticky and nonplastic; 60 percent gravel, 10 percent cobbles; strongly effervescent (4 percent calcium carbonate); moderately alkaline.
TYPE LOCATION: Las Animas County, Colorado; located about 100 feet north and 900 feet east of the southwest corner of sec. 8, T. 33 S., R. 63 W.; Trinidad East USGS quad; lat. 37 degrees 10 minutes 40 seconds N. and long. 104 degrees 29 minutes 01 seconds W., NAD 1983.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section is moist intermittently April through August, dry October through February; ustic moisture regime bordering on aridic.
Mean annual soil temperature: 48 to 52 degrees F
Mean summer soil temperature: 68 to 74 degrees F
Depth to lithic contact: 72 or more inches
Depth to calcic horizon: 14 to 30 inches
Thickness of the cambic horizon: 10 to 15 inches
Depth to lithologic discontinuity: 14 to 30 inches
Particle-size control section (weighted average):
Clay content: 10 to 22 percent
Sand content: 45 to 75 percent
Rock fragments: 35 to 65 percent
A horizon:
Hue: 7.5YR or 10YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 2 or 3
Clay content: 18 to 27 percent
Texture of the fine earth fraction: loam or fine sandy loam
Rock fragments: 15 to 60 percent
Calcium carbonate equivalent: 0 to 5 percent
Reaction: slightly alkaline or moderately alkaline
Bw horizon:
Hue: 5YR or 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 to 6
Texture of the fine earth fraction: loam, clay loam, sandy clay loam
Clay content: 18 to 30 percent
Rock fragments: 35 to 60 percent
Calcium carbonate equivalent: 2 to 15 percent
Reaction: slightly alkaline or moderately alkaline
A BCk horizon is present in some pedons
2Bk horizon:
Hue: 7.5YR or 10YR
Value: 6 to 8 dry, 5 or 6 moist
Chroma: 3 or 4
Texture of the fine earth fraction: sandy loam, loam
Clay content: 8 to 18 percent
Rock fragments: 35 to 75 percent
Calcium carbonate equivalent: 15 to 40 percent
Reaction: moderately alkaline or strongly alkaline
2C horizon:
Hue: 7.5YR or 10YR
Value: 5 to 7 dry, 4 to 6 moist
Chroma: 2 to 4
Texture of the fine earth fraction: loamy sand, loamy coarse sand, coarse sandy loam, coarse sand
Clay content: 1 to 15 percent
Rock fragments: 35 to 75 percent
Calcium carbonate equivalent: 1 to 15 percent
Reaction: moderately alkaline or strongly alkaline
COMPETING SERIES: These are the
Buckndoe (WV),
Katzine (UT),
Saraton (WY),
Tinaja (NM),
Upler (NM), and
Yatne (UT) series.
Buckndoe soils: have a cemented hardpan at depths of 40 to 60 inches.
Katzine soils: are dry
May and June and average less than 18 percent clay in PSCS.
Saraton soils: have a paralithic contact at deths of 20 to 40 inches.
Tinaja soils: lack a cambic horizon and average 18 to 30 percent clay in PSCS.
Upler soils: have a calcic horizon at depths of 5 to 11 inches and a moisture control section that is evenly distributed throughout the year.
Yatne soils: are driest in May and June, with wet periods in August and December.
GEOGRAPHIC SETTING:
Parent material: sandy and gravelly alluvium
Landform: fan remnant, terrace, fans
Slopes: 1 to 25 percent
Elevation: 4,800 to 6,500 feet
Mean annual temperature: 48 to 54 degrees F
Mean annual precipitation: 12 to 16 inches
Precipitation pattern: continental climate
Wettest period: April through August
Driest period: November through February
Frost-free period: 120 to 155 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Baca, Kandrix, Kimera, and Midway series. The Baca soils average less than 35 percent rock fragments, have greater than 35 percent clay and are on gently sloping treads. Kandrix and Kimera soils average less than 35 percent rock fragments and are on gently sloping treads. The Midway soils are less than 20 inches to paralithic contact and are on risers.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained, medium runoff, and moderately rapid permeability.
USE AND VEGETATION: Rangeland and wildlife habitat. The native vegetation is blue grama, sideoats grama, little bluestem, sand dropseed, Gambel's oak, true mountain mahogany, pinyon and juniper.
DISTRIBUTION AND EXTENT: Southeastern Colorado; LRR E and G, MLRA 49, 67, and small amounts in 69; moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Las Animas County, Colorado, 2007. Las Animas and parts of Huerfano County soil survey area, Colorado. The name is from a major drainage in the area.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: The zone from 10 to 40 inches. (Part of the Bw, 2Bk, and part of the 2C horizons)
Ochric epipedon: The zone from 0 to 6 inches. (A horizon)
Cambic horizon: The zone from 6 to 20 inches. (Bw horizon)
Calcic horizon: The zone from 20 to 37 inches. (2Bk horizons)
Lithologic discontinuity: At 20 inches. (2Bk and 2C horizons)
Remarks: This soil was determined to have a consistent cambic horizon and lithologic discontinuity, separating this from the Ildefonso series. In addition, the soil moisture regime was determined to be dominantly aridic-ustic.
The assignment of the cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.
Taxonomic Version: Keys to Soil Taxonomy Tenth Edition, 2006