LOCATION WUKOKI AZEstablished Series
TAXONOMIC CLASS: Ashy-skeletal over fragmental or cindery, mixed, mesic Vitrandic Haplocambids
TYPICAL PEDON: Wukoki extremely gravelly loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 2 inches; brown (10YR 5/3) extremely gravelly loam, dark brown (7.5YR 3/2) moist; weak thick platy structure; slightly hard, very friable, slightly sticky and slightly plastic; few fine roots; many very fine and fine vesicular pores; 75 percent cinders; slightly alkaline (pH 7.7); clear smooth boundary. (1 to 3 inches thick)
A2--2 to 10 inches; brown (10YR 5/3) very gravelly loam, dark brown (7.5YR 3/2) moist; weak fine granular and subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; few very fine and fine tubular and common very fine interstitial pores; 40 percent cinders; slightly alkaline (pH 7.8); clear wavy boundary. (0 to 8 inches thick)
Bw1--10 to 15 inches; pale brown (10YR 6/3) very gravelly loam, dark yellowish brown (10YR 3/4) moist; weak very fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; few very fine and fine tubular and common very fine interstitial pores; 50 percent cinders; strongly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (2 to 5 inches thick)
Bw2--15 to 18 inches; light yellowish brown (10YR 6/4) extremely gravelly loam, dark yellowish brown (10YR 3/4) moist; weak very fine granular structure appearing massive in place; soft, very friable; common very fine and fine roots; common very fine interstitial pores; 60 percent cinders; violently effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (2 to 10 inches thick)
2Ck--18 to 65 inches; dark gray (10YR 4/1) cinders, black (10YR 2/1) moist; single grained; cinders in upper 15 to 20 inches have coatings of calcium carbonate, decreasing with depth; violently effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Coconino County, Arizona; about 28 miles north of Flagstaff on the Co-Bar Ranch; 2,000 feet east and 250 feet south of the northwest corner of section 36, T.26 N., R.7 E.
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. Ustic aridic soil moisture regime.
Soil temperature: 48 - 57 degrees F.
Rock fragments: averages 40 to 75 percent cinders by volume; 65 to 75 percent cinders on the surface
Depth to cinders: 10 to 20 inches
A horizon
Hue: 7.5YR, 10YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 2 to 4, dry or moist
Bw horizon
Hue: 7.5YR, 10YR
Value: 5 or 6 dry, 3 or 4 moist
Chroma: 3 or 4, dry or moist
Texture: Loam, coarse sandy loam (average 18 to 25 percent clay)
C horizon
Hue: 2.5YR to 10YR
Value: 3 or 4 dry, 2 or 3 moist
Chroma: 1 or 2, dry or moist
Cinders: averages 95 to 100 percent by volume
COMPETING SERIES: This is Lomaki (AZ) series. Lomaki soils have cinders at depths of 20 to 40 inches.
GEOGRAPHIC SETTING: Wukoki soils are on hills, fan terraces, and cinder cones at elevations of 4,800 to 6,000 feet. Slopes range from 1 to 60 percent. The soils formed in pyroclastics and cinders. Mean annual precipitation is 8 to 14 inches. Mean annual air temperature is 46 to 55 degrees F. The frost-free period is 120 to 165 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aut, Tuweep, and Winona soils and the competing Lomaki soils. Aut soils have bedrock at moderate depths. Tuweep soils are fine-loamy. Winona soils are shallow over bedrock.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; slow to medium runoff; moderately rapid permeability.
USE AND VEGETATION: These soils are used for livestock grazing and wildlife habitat. Vegetation is mainly black grama and blue grama, winterfat and rabbitbrush.
DISTRIBUTION AND EXTENT: Northern Arizona. This series is moderately extensive. MLRA 35 & 39.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Coconino County; Soil survey of Coconino County Area, AZ, Central Part; 1980.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 10 inches (A1, A2 horizons)
Cambic horizon - The zone from 10 to 18 inches (Bw1, Bw2 horizons)
Cinder deposit at a depth of 18 inches
Classified according to Soil Taxonomy Second Edition, 1999; Keys to Soil Taxonomy Tenth Edition, 2006.
ADDITIONAL DATA: NSSL sample S77AZ-005-003