LOCATION YELLOWHORSE AZEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Leptic Udic Haplusterts
TYPICAL PEDON: Yellowhorse cobbly loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 2 inches; reddish brown (5YR 4/3) cobbly loam, dark reddish brown (5YR 3/3) moist; weak thin platy structure; slightly hard, friable, slightly sticky and slightly plastic; many fine and very fine roots; common very fine vesicular and tubular pores; 5 percent gravel, 20 percent cobble and 5 percent stones; noneffervescent; neutral (pH 7.2); abrupt smooth boundary. (1 to 7 inches thick)
Bt--2 to 10 inches; reddish brown (5YR 4/3) clay loam, dark reddish brown (5YR 3/3) moist; moderate medium subangular blocky structure; very hard, firm, sticky and plastic; common fine and very fine roots; common fine and very fine tubular and interstitial pores; many pressure faces and few faint clay films lining pores; 5 percent gravel; noneffervescent; slightly alkaline (pH 7.4); abrupt smooth boundary. (5 to 15 inches thick)
Btss--10 to 24 inches; reddish brown (5YR 4/4) clay, reddish brown (5YR 4/3) moist; strong coarse angular blocky structure; extremely hard, extremely firm, very sticky and very plastic; few very fine roots; common fine interstitial pores; many pressure faces and many intersecting slickensides forming wedges; few faint clay films lining pores; 5 percent gravel; noneffervescent; slightly alkaline (pH 7.6); abrupt irregular boundary. (5 to 20 inches thick)
R--24 inches; basalt.
TYPE LOCATION: Mohave County, Arizona; about 13.8 miles south of the Arizona-Utah state line and 16.9 miles east of the Arizona-Nevada state line; about 1900 feet south and 200 feet west of the northeast corner of section 12, T.39 N., R.14 W.; 36 degrees, 48 minutes, 18 seconds north latitude and 113 degrees, 44 minutes, 08 seconds west longitude.
RANGE IN CHARACTERISTICS:
Soil Moisture: Intermittently moist in some part of the soil moisture control section during July - September and December - February. Driest during May and June. Typic ustic soil moisture regime.
Soil temperature: 47 to 56 degrees F.
Organic Matter: 1 to 2 percent in mollic epipedon
Depth to bedrock: 20 to 40 inches
Cracking: Deep, wide cracks are open from 90 to 150 days cumulative.
A horizon
Hue: 5YR, 7.5YR or 10YR
Value: 3 to 5 dry, 2 or 3 moist
Chroma: 2 to 4, dry or moist
Reaction: neutral to slightly alkaline
Rock fragments: 0 to 5 percent stones, 5 to 20 percent cobble, 5 to 10 percent gravel
Bt horizon
Hue: 5YR, 7.5YR
Value: 3 to 5 dry, 3 or 4 moist
Chroma: 2 to 6, dry or moist
Texture: Clay loam, clay (35 to 60 percent clay)
Reaction: neutral to slightly alkaline
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Yellowhorse soils are on mesas and plateaus and have slopes gradients that range from 1 to 10 percent. These soils formed in colluvium and residuum alluvium derived dominantly from basalt and other volcanic rocks. Elevations range from 5900 to 7200 feet. The mean annual air temperature is 45 to 50 degrees F. Mean annual precipitation is 17 to 25 inches. The frost-free period is 120 to 135 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Luzena, Delenbaw, and Pocum series. Luzena soils have a lithic contact within 20 inches of the surface. Delenbaw soils contain more than 35 percent rock fragments. Pocum soils have a petrocalcic horizon within 20 inches of the surface.
DRAINAGE AND PERMEABILITY: Well drained; low to medium runoff; very slow permeability.
USE AND VEGETATION: Yellowhorse soils are used for livestock grazing, wildlife habitat and timber production. The present vegetation is ponderosa pine, Gambel oak, juniper, big sagebrush, Utah serviceberry, black sagebrush, crested wheatgrass, intermediate wheatgrass, western wheatgrass and junegrass.
DISTRIBUTION AND EXTENT: Northwestern Arizona. This series is of small extent. MLRA is 35.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Mohave County, Arizona; Soil survey of Shivwits Area, Arizona, Part of Mohave County; 1994.
REMARKS: Formerly classified as Udic Chromusterts.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from 0 to 10 inches (A and Bt horizons)
Intersecting slickensides - The zone from 10 to 24 inches (Btss horizon)
Lithic contact - The boundary at 24 inches (2R horizon)
Classified according to Soil Taxonomy Second Edition, 1999; Keys to Soil Taxonomy Tenth Edition, 2006.