LOCATION BIGHAWK                 AZ

Established Series
DJP/JIC/JMH
10/2013

BIGHAWK SERIES

The Bighawk series consists of very deep, somewhat excessively drained soils that formed in alluvium from pyroclastics and cinders. Bighawk soils are on alluvial fans, and plateaus. Slopes range from 1 to 5 percent. The mean annual precipitation is about 12 inches and the mean annual air temperature is about 52 degrees F. (11.1 degress C.)

TAXONOMIC CLASS: Ashy-skeletal, glassy, mesic Vitrandic Haplocambids

TYPICAL PEDON: Bighawk gravelly sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)

A--0 to 2 inches (0 to 5 cm); brown (10YR 5/3) gravelly sandy loam, brown (10YR 4/3), moist; 12 percent clay; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many interstitial pores; 30 percent cinders; strongly effervescent, 8 percent calcium carbonate equivalent; moderately alkaline, pH 8.0; clear smooth boundary.

Bk1--2 to 12 inches (5 to 30 cm); brown (10YR 5/3) very gravelly sandy loam, dark grayish brown (10YR 4/2), moist; 13 percent clay; moderate medium granular parts to weak thin platy structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots throughout; many carbonate coats around rock fragments, carbonate, finely disseminated throughout; 40 percent cinders; violently effervescent, 10 percent calcium carbonate equivalent; moderately alkaline, pH 8.0; gradual smooth boundary.

Bk2--12 to 19 inches (30 to 47 cm); brown (10YR 5/3) very stony sandy loam, dark grayish brown (10YR 4/2), moist; 14 percent clay; weak fine granular and fine angular blocky structure; soft, very friable, slightly sticky and nonplastic; many very fine and common fine roots throughout; many carbonate coats around rock fragments, carbonate, finely disseminated throughout; 15 percent stones and 20 percent cinders; violently effervescent, 12 percent calcium carbonate equivalent; moderately alkaline, pH 8.4; gradual smooth boundary.

Bk3--19 to 24 inches (47 to 60 cm); brown (10YR 5/3) very gravelly sandy loam, dark grayish brown (10YR 4/2), moist; 15 percent clay; massive; soft, very friable, slightly sticky and nonplastic; common very fine roots throughout; many carbonate coats around rock fragments, carbonate, finely disseminated throughout; 40 percent cinders; violently effervescent, 12 percent calcium carbonate equivalent; moderately alkaline, pH 8.4; gradual smooth boundary.

Bk4--24 to 60 inches (60 to 152 cm); brown (10YR 5/3) extremely gravelly sandy loam, dark grayish brown (10YR 4/2), moist; 12 percent clay; massive; loose, nonsticky and nonplastic; many carbonate coats around rock fragments, carbonate, finely disseminated throughout; 60 percent cinders; violently effervescent, 13 percent calcium carbonate equivalent; strongly alkaline, pH 8.6.

TYPE LOCATION: Wupatki National Monument, Coconino County, Arizona; Geographic Coordinate System: 35 34' 23.5'' north, 111 30' 32.6'' west NAD83.

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: 52 to 56 degrees Fahrenheit (11.1 to 13.3 degrees Celsius)

Particle-size control section (weighted average)
Clay content: 12 to 18 percent
Rock Fragments: 35 to 55 percent cinders
Volcanic Glass: 30 to 40 percent

Depth to cambic horizon: 2 to 19 inches (5 to 47 cm)

A Horizon
Hue: 7.5YR, 10YR
Value: 3 to 5 dry, 2.5 to 4 moist
Chroma: 1 to 3, dry or moist
Texture: sandy loam
Clay: 8 to 14 percent
Calcium carbonate equivalent: 5 to 10 percent
Rock fragments: 20 to 60 percent cinders
Reaction: slightly alkaline to moderately alkaline

Bk Horizons
Hue: 7.5YR, 10YR
Value: 4 to 7 dry, 4 to 6 moist
Chroma: 2 to 4, dry or moist
Texture: sandy loam, fine sandy loam, loam
Clay: 10 to 18 percent
Calcium carbonate equivalent: 5 to 15 percent
Rock fragments: 35 to 60 percent cinders
Reaction: moderately alkaline to strongly alkaline

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Bighawk soils are on alluvial fans of cinders at elevations of 5,370 to 5,720 feet (1,638 to 1,744 meters). Slopes range from 1 to 5 percent. These soils formed in alluvium derived from cinders. The mean annual precipitation is 10 to 14 inches (254 to 356 millimeters) and occurs as thunderstorms during July to September and as gentle rains and snowfall during December and January. The mean annual air temperature is 50 to 54 degrees Fahrenheit (10.0 to 12.2 degrees Celsius). The frost-free period is 135 to 165 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Flaco (AZ), Chedeski (AZ), and Peshlaki (AZ), soils. Flaco soils have calcic and argillic horizons, are moderately deep, and have more than 14 percent clay and less than 35 percent gravel fragments in the particle size control section. Chedeski and Peshlaki soils are very shallow and shallow to bedrock, and have less than 27 percent clay in the particle size control section.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; very low runoff; moderate or moderately rapid permeability.

USE AND VEGETATION: Used for livestock grazing and wildlife habitat. Vegetation includes galleta, oneseed Juniper, Russian thistle, black grama, needle and thread, and alkali sacaton.

DISTRIBUTION AND EXTENT: Northern Arizona. Bighawk soils are of moderate extent. This soil is named after the valley at the type location. MLRA 35 Land Resource Unit 35.1.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona

SERIES ESTABLISHED: Wupatki National Monument, Coconino County, Arizona; Soil Survey of Coconino County Area, AZ, Central Part; 2013

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - the zone from 0 to 2 inches (0 to 5 cm) (A horizons)

Cambic horizon - the zone from 2 to 19 inches (5 to 47 cm) (Bk1 and Bk2 horizons)

Volcanic glass - exceeds 30 percent in mineral class control section

Particle size control section - the zone from 10 to 40 inches (25 to 100 cm) (Bk horizons)

Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Eleventh Edition, 2010

ADDITIONAL DATA: Laboratory Data NSSL Pedon # S2012AZ005004
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National Cooperative Soil Survey
U.S.A.