LOCATION AUT AZEstablished Series
TAXONOMIC CLASS: Fine-loamy, carbonatic, mesic Aridic Calciustolls
TYPICAL PEDON: Aut gravelly loam - rangeland. (Colors are for dry unless otherwise noted.)
A1--0 to 2 inches; brown (10YR 5/3) gravelly loam, dark brown (10YR 3/3) moist; weak thin platy structure parting to weak very fine granular; slightly hard, very friable, nonsticky and nonplastic; many fine roots; common very fine and fine vesicular and irregular pores; 15 percent basalt pebbles; strongly effervescent; moderately alkaline (pH 8.0); abrupt smooth boundary. (2 to 6 inches thick)
A2--2 to 7 inches; brown (10YR 5/3) gravelly loam, dark brown(10YR 3/3) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; many very fine roots; few fine tubular and irregular pores; 15 percent basalt pebbles; strongly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (4 to 10 inches thick)
A3--7 to 12 inches; brown (10YR 4/3) cobbly loam, dark brown (10YR 3/3) moist; weak to moderately subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; many very fine roots; few fine tubular and irregular pores; 20 percent cobbles; violently effervescent; moderately alkaline (pH 8.0); gradual wavy boundary. (3 to 10 inches thick)
Bk1--12 to 17 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; many very fine roots; few fine tubular pores; violently effervescent; moderately alkaline (pH 8.0); gradual wavy boundary. (4 to 8 inches thick)
Bk2--17 to 26 inches; light brownish gray (10YR 6/2) very cobbly loam, yellowish brown (10YR 5/4) moist; massive; slightly hard, friable, slightly sticky and nonplastic; many very fine roots; 20 percent pebbles and 15 percent cobbles; violently effervescent; moderately alkaline (pH 8.0); diffuse broken boundary. (2 to 10 inches thick)
Bk3--26 to 38 inches; very dark gray (2.5Y 3/1) cobbly loam, black (2.5Y 2.5/1) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; one-half inch lime fragments and 15 percent lime-coated pebbles, 25 percent lime-coated cobbles; lime coating is strongly cemented and is white (7.5YR 8/1) dry and pinkish white (7.5YR 8/2) moist; porous basalt fragments are partially filled with lime; violently effervescent; moderately alkaline (pH 8.0); abrupt wavy boundary. (3 to 12 inches thick)
2R--38 inches; basalt; common carbonate coatings in joints.
TYPE LOCATION: Coconino County, Arizona; approximately 18 miles north of Williams; 1,200 feet east of the SW corner of sec. 33, T. 25 N., R. 2 E.
RANGE IN CHARACTERISTICS:
Soil Moisture - Intermittently moist in some parts of the SMCS in July-September and December-February. Aridic ustic moisture regime.
Depth to calcic horizon - 15 to 20 inches
Depth to bedrock - 20 to 40 inches
Rock Fragments - 5 to 30 percent pebbles
A horizon - Hue: 7.5YR or 10YR
Value: 4 or 5
Chroma: 2 or 3
Texture: L (15 to 25 percent clay)
Organic matter: more than 1 percent
Reaction: Mildly to moderately alkaline
Bk horizon: Hue: 7.5YR or 10YR
Value: 3 through 5
Chroma: 2 or 3
Texture: GR-L, L (15 to 25 percent clay)
Reaction: Mildly or moderately alkaline
Carbonates More than 40 percent
COMPETING SERIES: This is the Conlen series. Conlen soils are very deep.
GEOGRAPHIC SETTING: The Aut soils are at elevations of 5,000 to 6,800 feet on plateaus and mesas. Slopes range from 0 to 8 percent. The soils formed in alluvium from limestone and basalt. The mean annual temperature ranges from 49 to 54 degrees F. The average annual precipitation ranges from 11 to 14 inches and occurs as summer thunderstorms and as rain and snow in the winter. The frost-free season ranges from 120 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Apache, Cross, Lynx, Wilaha, Thunderbird, and Ziegler soils. Apache and Cross soils have bedrock at a depth of less than 20 inches. Thunderbird, Wilaha and Ziegler soils have an argillic horizon. Lynx soils lack bedrock within a depth of 40 inches and lack a calcic horizon within a depth of 60 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.
USE AND VEGETATION: These soils are used for grazing. The native vegetation is blue grama, black grama, alkali sacaton, sideoats grama, galleta, needle-and-thread, indian ricegrass, fourwing saltbush, winterfat, juniper and pinyon pine.
DISTRIBUTION AND EXTENT: Northern Arizona. These soils are moderately extensive. MLRA 35.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Coconino County Area, Arizona, Central Part 1980.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 12 inches (A1, A2 and A3 horizons)
Calcic horizons - 17 to 38 inches (Bk2 and Bk3 horizons)
Aridic feature - dry in some part of the moisture control section for 0.6 or more of the time.
Classified according to Keys to Soil Taxonomy Ninth Edition, 2003
ADDITIONAL DATA: NSSL sample S77 AZ-5-9.