LOCATION SUNSETCRATER            AZ

Established Series
MWB/JMH/DJP
04/2022

SUNSETCRATER SERIES

The Sunsetcrater series consists of very deep, well drained soils that formed in coarse tephra deposited over clayey tephra derived from volcanic rock. Sunsetcrater soils are on cinder cones and lava fields. Slopes range from 1 to 35 percent. The mean annual precipitation is about 18 inches (457 millimeters) and the mean annual air temperature is about 44 degrees F. (6.7 degrees Celcius)

TAXONOMIC CLASS: Ashy-skeletal, glassy, frigid Andic Haplustepts

TYPICAL PEDON: Sunsetcrater extremely gravelly loamy sand - woodland. (Colors are for dry soil unless otherwise noted.)

C1--0 to 2 inches (0 to 5 cm); very dark gray (7.5YR 3/1) extremely gravelly loamy sand, black (7.5YR 2.5/1), moist; 6 percent clay; single grain; loose, nonsticky and nonplastic; many very fine roots; 84 percent cinder fragments; noneffervescent; slightly alkaline, pH 7.6; clear smooth boundary.

C2--2 to 7 inches (5 to 18 cm); dark gray (7.5YR 4/1) extremely gravelly loamy sand, very dark gray (7.5YR 3/1), moist; 7 percent clay; weak fine granular structure; loose, nonsticky and nonplastic; many very fine, fine, and medium roots; few very fine irregular pores; 65 percent cinder fragments; noneffervescent; slightly alkaline, pH 7.4; abrupt smooth boundary.

C3--7 to 12 inches (18 to 30 cm); very dark gray (7.5YR 3/1) extremely gravelly coarse sand, black (7.5YR 2.5/1), moist; 5 percent clay; single grain; loose, nonsticky and nonplastic; many very fine, fine, and medium roots; 88 percent cinder fragments; noneffervescent; slightly alkaline, pH 7.4; abrupt wavy boundary.

2Bw--12 to 21 inches (30 to 53 cm); brown (7.5YR 5/4) very gravelly sandy clay loam, brown (7.5YR 4/4), moist; 26 percent clay; moderate fine subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; many very fine, fine, medium, and coarse roots; many very fine and fine tubular pores; 53 percent cinder fragments; noneffervescent; slightly alkaline, pH 7.6; abrupt wavy boundary.

2C--21 to 60 inches (53 to 152 cm); light brown (7.5YR 6/4) and very dark gray (7.5YR 3/1) extremely gravelly loamy sand, brown (7.5YR 4/4) and black (7.5YR 2.5/1), moist; 8 percent clay; single grain; loose, nonsticky and nonplastic; common very fine, and few fine roots; 84 percent cinder fragments; noneffervescent; slightly alkaline, pH 7.6.

TYPE LOCATION: Sunset Crater National Monument, Coconino County, Arizona; Geographic Coordinate System: 35 degrees 21 minutes 39.50 seconds north, 111 degrees 32 minutes 0.50 seconds' 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. Typic ustic soil moisture regime.

Soil Temperature: 44 to 48 degrees Fahrenheit (6.6 to 8.8 degrees Celsius)

Particle-size control section (weighted average)
Clay content: 1 to 30 percent
Rock fragments: 35 to 85 percent cinders
Volcanic glass: 30 to 40 percent

C horizons
Hue: 5YR, 7.5YR
Value: 2.5 to 4 dry, 2.5 or 3 moist
Chroma: 1 or 2, dry or moist
Texture: coarse sand, loamy sand
Clay: 1 to 10 percent
Rock fragments: 60 to 88 percent cinders
Reaction: neutral to slightly alkaline

2Bw horizon
Hue: 5YR, 7.5YR
Value: 3 to 5 dry, 3 or 4 moist
Chroma: 3 or 4, dry or moist
Texture: sandy clay loam
Clay: 20 to 30 percent
Rock fragments: 35 to 55 percent cinders
Reaction: neutral to slightly alkaline

2C horizon
Hue: 5YR, 7.5YR
Value: 3 to 6 dry, 3 or 4 moist
Chroma: 1 to 4, dry or moist
Texture: loamy sand
Clay: 2 to 10 percent
Rock fragments: 60 to 88 percent cinders
Reaction: neutral to slightly alkaline

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Sunsetcrater soils are on cinder cones and lava fields at elevations of 6,500 to 7,500 feet (1,981 to 2,286 meters). Slopes range from 1 to 35 percent. These soils formed in coarse tephra deposited over clayey tephra derived from volcanic rock. The mean annual precipitation is 18 to 22 inches (457 to 559 millimeters) and occurs as thunderstorms during July to September and as snow December to February. The mean annual air temperature is 42 to 46 degrees Fahrenheit (5.5 to 7.7 degrees Celsius). The frost-free period is 100 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blackash (AZ), Cinderhill (AZ), and Kana`a (AZ) soils. Blackash soils have a Ashy particle size and have less than 35 percent rock fragments or cinders in the control section. Cinderhill soils do not have a cambic horizon. Kana'a soils have a Cindery particle size and have greater than 60 percent rock fragments or cinders in the control section.

DRAINAGE AND PERMEABILITY: Well drained; high runoff; moderate to very rapid permeability.

USE AND VEGETATION: Used primarily for wildlife habitat, recreation, and grazable woodland. Ponderosa pine is dominant with sand bluestem, blue grama, and apache plum.

DISTRIBUTION AND EXTENT: Northern Arizona. Sunsetcrater soils are of small extent. This soil is named after a park near the type location. MLRA 39 Land Resource Unit 39.1 above the Mogollon Rim.

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

SERIES ESTABLISHED: Sunset Crater National Monument, Coconino County, Arizona; Soil Survey of Oak Creek-San Francisco Peaks Area, AZ, Part of Coconino County; 2013

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

Ochric epipedon - the zone from 0 to 2 inches (0 to 5 cm) (C1 horizon)

Cambic horizon - the zone from 12 to 21 inches (30 to 53 cm) (2Bw horizon)

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) (C3, 2Bw, 2C horizons)

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

ADDITIONAL DATA: Laboratory Data NSSL Pedon # S2012AZ005001

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National Cooperative Soil Survey
U.S.A.