LOCATION ROUBIDEAU COEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Aridic Haplustalfs
TYPICAL PEDON: Roubideau loam in grassland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 2 inches; brown (7.5YR 5/3) loam, dark brown (7.5YR 3/3) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine roots throughout; noneffervescent; neutral (pH 7.0); abrupt smooth boundary.
A2--2 to 6 inches; brown (7.5YR 5/3) loam, dark brown (7.5YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine roots throughout; few medium discontinuous tubular pores; noneffervescent; neutral (pH 7.0); abrupt smooth boundary.
Bt1--6 to 12 inches; brown (7.5YR 5/4) loam, brown (7.5YR 4/4) moist; moderate medium subangular blocky structure; very hard, firm, slightly sticky and slightly plastic; common very fine roots throughout; few very fine discontinuous tubular pores; few faint patchy clay films on faces of peds and in pores; noneffervescent; neutral (pH 7.0); clear smooth boundary.
Bt2--12 to 23 inches; brown (7.5YR 5/4) loam, brown (7.5YR 4/4) moist; moderate medium prismatic structure; very hard, firm, slightly sticky and slightly plastic; common very fine roots throughout; common very fine discontinuous tubular pores; few faint patchy clay films on faces of peds and in pores; noneffervescent; neutral (pH 7.0); clear smooth boundary.
Bt3--23 to 36 inches; strong brown (7.5YR 5/6) loam, strong brown (7.5YR 4/6) moist; moderate medium subangular blocky structure; very hard, firm, slightly sticky and slightly plastic; common fine roots throughout; few very fine vesicular pores and few fine discontinuous tubular pores; common faint continuous clay films on faces of peds and in pores; noneffervescent; slightly alkaline (7.4); clear wavy boundary.
Bt4--36 to 38 inches; strong brown (7.5YR 5/6) channery loam, strong brown (7.5YR 4/6) moist; moderate medium subangular blocky structure; very hard, firm, slightly sticky and slightly plastic; common medium roots throughout; common faint continuous clay films on faces of peds and in pores; noneffervescent; 5 percent sandstone gravel and 15 percent sandstone channers; slightly alkaline (pH 7.4); clear smooth boundary.
2R--38 inches; brownish yellow Cliffhouse sandstone.
TYPE LOCATION: Montezuma County, Colorado; about 50 feet west of the Y intersection on Long Mesa, Mesa Verde National Park; about 3,200 feet north and 100 feet west of the southeast corner of sec. 31, T. 35 N., R 15 W. USGS Wetherill Mesa, Colorado topographic quadrangle; lat. 37 degrees 14 minutes 52 seconds N. and long. 108 degrees 32 minutes 11 seconds W., NAD27
RANGE IN CHARACTERISTICS:
Soil moisture regime: ustic bordering on aridic
Soil temperature regime: mesic
Mean annual soil temperature: 52 degrees F
Depth to lithic contact: 20 to 40 inches to hard sandstone
Particle-size control section:
Clay content: 18 to 35 percent
A horizon:
Hue: 7.5YR or 10YR
Value: 5 to 7 (3 to 6 moist)
Chroma: 1 to 4
Rock fragments: 0 to 5 percent gravel
Reaction: neutral or slightly alkaline
Bt horizon:
Hue: 5YR or 7.5YR
Value: 5 to 7 (4 to 6 moist)
Chroma: 3 to 6
Texture: loam, clay loam, or silty clay loam
Rock fragments: 0 to 20 percent in the lower part and next to bedrock, mainly gravel and channers
Reaction: neutral or slightly alkaline
COMPETING SERIES: These are the Altega, Amal, Buick, Chita, Elpedro, Keiser, Klinedraw, Moncha, Oshoto, Pulpit, Sharps, Verde, Wetherill, and Wiley series. Altega, Amal, Buick, Chita, Elpedro, Keiser, Oshoto, Moncha, Wetherill, and Wiley soils are very deep. Klinedraw and Sharps soils are moderately deep to paralithic contact. Pulpit soils contain visible secondary carbonates in the lower part of the solum. Verde soils have a fragipan-like horizon.
GEOGRAPHIC SETTING:
Parent material: eolian material derived from sandstone
Landform: mesas
Slopes: 1 to 6 percent
Elevation: 6,800 to 7,800 feet
Mean annual temperature: 47 to 50 degrees F
Mean annual precipitation: 16 to 19 inches
Precipitation is fairly evenly distributed throughout the year with July and August being slightly wetter and June being slightly dryer.
Frost-free period: 130 to 150 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Morefield and Arabrab series. All soils are found in the same area. Morefield soils are very deep and Arabrab soils are shallow.
DRAINAGE AND PERMEABILITY: well drained, low or medium runoff, moderately slow permeability
USE AND VEGETATION: Used as wildlife habitat. Native vegetation is pinyon, juniper, shrubs, junegrass, and bluegrass.
DISTRIBUTION AND EXTENT: Southwest Colorado. LRR D, MLRA 36. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Montezuma County, Colorado. Western Colorado Reconnaissance Survey, 1939.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: from 0 to 6 inches. (A1, A2)
Argillic horizon: from 6 to 38 inches. (Bt1, Bt2, Bt3, Bt4)
Lithic contact: at 38 inches.
Particle size control section: The zone from 6 to 26 inches. (Bt1, Bt2, Bt3)
The type location was changed in 1996 to better reflect the concepts of this series.
Classified according to Soil Taxonomy Second Edition, 1999