LOCATION ARABRAB CO+AZ NM
Established Series
Rev. BWC/DAD/TWH
11/2011
ARABRAB SERIES
The Arabrab series consists of shallow and very shallow, well drained soils that formed in reworked eolian deposits, slope alluvium derived from sandstone, or slope alluvium over residuum derived from sandstone. Arabrab soils are on structural benches, mesas, cuestas, hills, and ridges. Slopes range from 1 to 60 percent. Mean annual precipitation is about 15 inches and the mean annual temperature is about 48 degrees F.
TAXONOMIC CLASS: Loamy, mixed, superactive, mesic Lithic Haplustalfs
TYPICAL PEDON: Arabrab fine sandy loam, pinyon-juniper woodland at an elevation of 7,360 feet. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 2 inches (0 to 6 cm); slightly decomposed needles and twigs, abrupt smooth boundary. (0 to 2 inches thick)
A--2 to 7 inches (6 to 19 cm); brown (7.5YR 4/3) fine sandy loam, dark brown (7.5YR 3/4) moist; weak medium granular structure; soft, friable, slightly sticky and nonplastic; noneffervescent; 10 percent channers, 2 percent flagstones; moderately alkaline (pH 8.0); clear wavy boundary. (2 to 7 inches thick)
Bt--7 to 12 inches (19 to 31 cm); yellowish red (5YR 5/6) sandy clay loam, yellowish red (5YR 4/6) moist; moderate medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few faint clay films on faces of peds; noneffervescent; 5 percent channers; slightly alkaline (pH 7.8); abrupt wavy boundary. (2 to 17 inches thick)
R--12 inches (31 cm); unweathered sandstone with top 1 cm weathered.
TYPE LOCATION: Montrose County, Colorado; about 18 miles southwest of Delta; about 900 feet west and 1,450 feet north of the southeast corner of section 2, T. 49 N., R. 13 W.; Cottonwood Basin USGS Topo Quad.; Latitude 38 degrees, 32 minutes 14 seconds N, longitude 108 degrees, 16 minutes 57 seconds W. NAD 1927.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section is affected by precipitation that is evenly distributed throughout the year with the exception of a slight increase in the spring and a more significant increase in the late summer. Melt water from snowpack causes these soils to be moist into April and early May. The soil is driest during late May and June. The soil has an ustic moisture regime bordering on aridic.
Mean annual soil temperature: 47 to 53 degrees F
Depth to argillic horizon: 2 to 4 inches
Depth to lithic contact: 6 to 20 inches
Lithology of rock fragments: sandstone
Particle-size control section:
Clay content: 18 to 35 percent
A horizon:
Hue: 5YR to 10YR
Value:3 to 5 dry or moist
Chroma: 2 to 4 dry or moist
Texture: sandy loam, fine sandy loam, loamy sand, or loam
Rock fragments: 0 to 75 percent
Calcium carbonate equivalent: 0 to 10 percent
Reaction: neutral to moderately alkaline
Bt horizon:
Hue: 5YR to 10YR
Value: 4 to 6 dry, 3 to 5 moist
Chroma: 3 to 6 dry or moist
Texture: sandy clay loam, clay loam, or loam
Rock fragments: 0 to 30 percent
Calcium carbonate equivalent: 0 to 10 percent
Reaction: neutral to moderately alkaline
Btk horizon (present in some pedons)
Hue: 5YR to 10YR
Value: 4 to 7 dry, 3 to 5 moist
Chroma: 2 to 6 dry or moist
Texture: sandy clay loam, clay loam, or loam
Rock fragments: 0 to 30 percent
Calcium carbonate equivalent: 1 to 15 percent
Reaction: neutral to moderately alkaline
Some pedons may have Bk horizons directly above the lithic contact.
COMPETING SERIES: These are the
Atarque,
Pescado,
Simitarq,
Valena, and
Verite series.
Atarque: have soil moisture control sections that are drier during April and early
May.
Pescado: have basalt rock fragments.
Simitarq: contain more than 35 percent clay in the lower Bt horizon
Valena: have granite rock fragments.
Verite: have typic ustic soil moisture regimes.
GEOGRAPHIC SETTING:
Parent material: reworked eolian material, slope alluvium derived from sandstone, or slope alluvium over residuum derived from sandstone
Landform: structural benches, mesas, cuestas, hills, and ridges
Slopes: 1 to 60 percent
Elevation: 6,300 to 8,500 feet
Mean annual temperature: 45 to 51 degrees F
Mean annual precipitation: 12 to 16 inches
Freeze-free period: 100 to 150 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are moderately deep
Evpark soils and the very deep
Parkelei soils.
DRAINAGE AND PERMEABILITY: well drained, low to high runoff, moderate permeability
USE AND VEGETATION: This soil is used for cordwood production, wildlife habitat, and livestock grazing. Vegetation is a twoneedle pinyon-Utah juniper woodland with an understory of blue grama, galleta, Indian ricegrass, bottlebrush squirreltail, junegrass, stemless goldenweed, pricklypear cactus, and Wyoming big sage.
DISTRIBUTION AND EXTENT: Colorado Plateau region of western and southwestern Colorado, northeast Arizona, northwest New Mexico, and southwest Utah. LRR D, MLRAs 35 and 36. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Uncompahgre Area, Montrose County, Colorado. 1984.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: The zone from 2 to 12 inches. (A and Bt horizons)
Ochric epipedon: The zone from 0 to 7 inches. (Oi and A horizons)
Argillic horizon: The zone from 7 to 12 inches. (Bt horizon)
Lithic contact: The contact with sandstone at 19 inches. (R layer)
The 3/2004 revision moved the type location to better represent the concept of the series.
The assignment of the cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.
Keys to Soil Taxonomy Eleventh Edition, 2010.
National Cooperative Soil Survey
U.S.A.