LOCATION BLACKASH                AZ

Established Series
MWB/JMH/DJP
10/2013

BLACKASH SERIES

The Blackash series consists of very deep, excessively drained soils that formed in tephra derived from volcanic rock. Blackash soils are on cinder cones and lava fields. Slopes range from 2 to 60 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 Celsius)

TAXONOMIC CLASS: Ashy, glassy, nonacid, frigid Vitrandic Ustorthents

TYPICAL PEDON: Blackash gravelly coarse sand - woodland. (Colors are for dry soil unless otherwise noted.)

C1--0 to 2 inches (0 to 5 cm); black (7.5YR 2.5/1) and reddish brown (5YR 4/3) gravelly coarse sand, dark reddish brown (5YR 3/3) and black (7.5YR 2.5/1), moist; 3 percent clay; single grain; loose, nonsticky and nonplastic; many very fine roots; 27 percent cinder fragments; noneffervescent; slightly alkaline, pH 7.4; clear smooth boundary.

C2--2 to 7 inches (5 to 18 cm); brown (7.5YR 4/3) gravelly loamy sand, dark brown (7.5YR 3/2), moist; 4 percent clay; weak fine granular structure; loose, nonsticky and nonplastic; many very fine and fine roots; many fine irregular pores; 31 percent cinder fragments; noneffervescent; neutral, pH 7.2; abrupt smooth boundary.

C3--7 to 16 inches (18 to 41 cm); black (7.5YR 2.5/1) and brown (7.5YR 4/3) gravelly loamy coarse sand, dark brown (7.5YR 3/2) and black (7.5YR 2.5/1), moist; 4 percent clay; weak fine granular structure; soft, loose, nonsticky and nonplastic; many medium, fine, and very fine roots; many fine irregular pores; 30 percent cinder fragments; noneffervescent; neutral, pH 7.2; gradual smooth boundary.

C4--16 to 60 inches (41 to 152 cm); black (7.5YR 2.5/1) and 5 percent brown (7.5YR 4/3) gravelly coarse sand, black (7.5YR 2.5/1) and 5 percent dark brown (7.5YR 3/2), moist; 3 percent clay; single grain; loose, nonsticky and nonplastic; many medium, fine, and very fine roots; many fine irregular pores; 23 percent cinder fragments; noneffervescent; slightly alkaline, pH 7.6.

TYPE LOCATION: Sunset Crater National Monument, Coconino County, Arizona; Geographic Coordinate System: 35 degees 21minutes 46.70 seconds north, 111degrees 29 minutes 32.60 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 10 percent
Rock fragments: 15 to 35 percent cinders
Volcanic glass: 30 to 40 percent

C Horizons
Hue: 5YR, 7.5YR, 10YR
Value: 2 to 4, dry or moist
Chroma: 1 to 3, dry or moist
Texture: coarse sand, sand, loamy coarse sand, loamy sand
Reaction: neutral to slightly alkaline

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Blackash 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 2 to 60 percent. These soils formed in 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 Sunsetcrater (AZ), Cinderhill (AZ), and Kana`a (AZ) soils. Cinderhill soils have a Ashy-skeletal particle size and have greater than 35 percent rock fragments or cinders in the control section. Kana'a soils have a Cindery particle size and have greater than 60 percent rock fragments or cinders in the control section. Sunsetcrater soils have a diagnostic cambic horizon with 18 to 30 percent clay in the particle size control section.

DRAINAGE AND PERMEABILITY: Excessively drained; low to negligible runoff; rapid 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. Blackash soils are of small extent. This soil is named after a lava flow 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)

Volcanic glass - the zone from 10 to 40 inches (25 to 100 cm) (C3 and C4 horizons)

Particle size control section - the zone from 10 to 40 inches (25 to 100 cm) (C3 and C4 horizons)

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

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National Cooperative Soil Survey
U.S.A.