LOCATION PURPLEHEART             AZ

Established Series
Rev. JPQ/GWA/JMH
02/2025

PURPLEHEART SERIES

The Purpleheart series consists of deep or very deep, well drained soils that formed in residuum of lava fields and bottoms of hillslopes. Purpleheart soils are on in-filled low positions. Slopes range from 0 to 8 percent. Mean annual precipitation is about 20 inches and the mean annual temperature is about 48 degrees F.

TAXONOMIC CLASS: Fine, smectitic, mesic Typic Paleustalfs

TYPICAL PEDON: Purpleheart-Pluto complex (Colors are for dry soil unless otherwise noted.)

A--0 to 3 inches (0 to 8 cm); dark brown (7.5YR 3/3) gravelly silty clay loam, very dark brown (7.5YR 2.5/3) moist; strong fine granular; slightly hard, very friable, moderately sticky, moderately plastic; common very fine and fine pores; common very fine and fine roots throughout; 5 percent cobbles and 15 percent gravel; noneffervescent; neutral (pH 6.6); abrupt wavy boundary.

Bt1--3 to 6 inches (8 to 15 cm); reddish brown (5YR 4/3) clay, dark reddish brown (5YR 3/3) moist; moderate fine angular blocky; moderately hard, firm, very sticky, very plastic; common very fine and fine pores; common very fine and fine, and few medium roots throughout; 20 percent distinct clay films on rock fragments and 10 percent faint clay films on all faces of peds; 2 percent gravel; noneffervescent; slightly acid (pH 6.4); abrupt wavy boundary.

Bt2--6 to 17 inches (15 to 43 cm); reddish brown (2.5YR 4/4) clay, red (2.5YR 4/6) moist; strong fine and medium angular blocky; extremely hard, extremely firm, very sticky, very plastic; few very fine and fine pores; few very fine, fine, medium, coarse, and very coarse roots throughout; 25 percent prominent clay films on all faces of peds; 2 percent gravel; noneffervescent; slightly acid, (pH 6.4); clear wavy boundary

Bt3--17 to 25 inches (43 to 64 cm); yellowish red (5YR 5/6) clay, yellowish red (5YR 4/6) moist; moderate fine and medium angular blocky; very hard, very firm, very sticky, very plastic; common very fine and fine pores; few very fine, fine, medium and coarse roots throughout; 5 percent faint clay films on all faces of peds and 20 percent prominent clay films on rock fragments; 2 percent gravel; noneffervescent; neutral (pH 7.0); abrupt wavy boundary

R--25 to 60 inches (64 to 152 cm); indurated basalt bedrock

TYPE LOCATION: Coconino County, Arizona; located about 11.3 kilometers (7.0 miles) east of Williams, Arizona; USGS Quadrangle Sitgreaves Mountain; Latitude 35.26247, Longitude -112.06213, Datum WGS84.

RANGE IN CHARACTERISTICS:
Soil moisture regime: typic ustic
Mean annual soil temperature: 46 to 50 degrees F
Rock fragment content: 0 to 15 percent
Depth to lithic contact: over 50 centimeters to bedrock
Particle-size control section:
Clay content: 35 to 60 percent

A horizon
Hue: 5YR or 7.5YR
Value: 3 or 4 (2.5 or 3 moist)
Chroma: 2 or 3, dry or moist
Calcium carbonate equivalent: 0 to 2 percent
Reaction: slightly alkaline or moderately alkaline

Bt horizons
Hue: 2.5YR to 7.5YR
Value: 4 or 5 (3 or 4 moist)
Chroma: 3 to 6, dry or moist
Texture: clay
Calcium carbonate equivalent: 0 to 2 percent
Sodium Adsorption Ratio (SAR): 0 to 2
Reaction: slightly acidic to slightly alkaline

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING:
Parent material: residuum derived from basalt
Landform: weathered lava fields
Slopes: 0 to 8 percent
Elevation: 6,500 to 7,600 feet
Mean annual air temperature: 45 to 49 degrees F
Mean annual precipitation: 18 to 24 inches
Precipitation peaks in July and August, and in winter months. May and June are much drier.
Frost-free period: 120 to 140 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Pluto and Procky soils. Pluto soils are not in depositional positions, have a mollic and an argillic horizon. Pluto soils have been complexed with Purpleheart soils. Procky soils have more fragments, are in colluvial positions, or related to relict faults or summits.

DRAINAGE AND PERMEABILITY: well drained, slow permeability

USE AND VEGETATION: These soils are used principally as grazing land. Native vegetation is mainly ponderosa pine, Gambel oak, blue grama, and Arizona fescue.

DISTRIBUTION AND EXTENT: Northern Arizona. MLRA 39.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.

SERIES ESTABLISHED: Coconino County, Arizona.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: from 0 to 8 centimeters. (A horizon)
Argillic horizon: from 8 to 64 centimeters. (Bt horizons).
Lab pedon: 09N0983
Name is derived from nearby Purple Heart Trail
Taxonomic Version: Keys to Soil Taxonomy, Thirteenth Edition, 2022
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National Cooperative Soil Survey
U.S.A.