LOCATION SHOWLOW AZ+NMEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aridic Argiustolls
TYPICAL PEDON: Showlow gravelly loam - grazeable woodland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 1 inch; brown (7.5YR 5/2) gravelly loam, dark brown (7.5YR 3/2) moist; weak thick platy structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many fine irregular and vesicular pores; 20 percent gravel; noneffervescent; neutral (pH 6.8); abrupt smooth boundary. (1 to 3 inches thick)
A2--1 to 3 inches; dark grayish brown (10YR 4/2) gravelly loam, very dark brown (10YR 2/2) moist; moderate fine platy structure; slightly hard, friable, slightly sticky and plastic; common fine and medium roots; few fine irregular and tubular pores; 20 percent gravel; noneffervescent; neutral (pH 6.9); abrupt smooth boundary. (2 to 4 inches thick)
2Bt1--3 to 12 inches; reddish brown (5YR 5/3) clay loam, dark reddish brown (5YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, friable, sticky and plastic; many fine roots and few coarse roots; many very fine tubular pores; few faint clay films on faces of peds; noneffervescent; neutral (pH 6.9); gradual smooth boundary. (5 to 10 inches thick)
2Bt2--12 to 24 inches; reddish brown (5YR 4/3) clay, dark reddish brown (5YR 3/4) moist; moderate coarse prismatic structure parting to moderate medium and coarse subangular and angular blocky; hard, firm, sticky and plastic; many fine roots; many very fine tubular pores; many distinct clay films on faces of peds; noneffervescent; neutral (pH 7.1); clear smooth boundary. (10 to 15 inches thick)
2Btk--24 to 31 inches; reddish brown (2.5YR 4/4) clay, dark reddish brown (2.5YR 3/4) moist; moderate coarse and medium angular and subangular blocky structure; very hard, very firm, very sticky and very plastic; few fine and coarse roots; few very fine tubular pores; 5 percent gravel; many continuous prominent clay films on faces of peds and lining pores; few slickensides; few fine to medium flecks of calcium carbonate in the lower portion of this horizon, strongly effervescent; slightly alkaline (pH 7.5); clear wavy boundary. (6 to 12 inches thick)
3Bk--31 to 44 inches; reddish brown (5YR 5/4) gravelly sandy clay loam, reddish brown (5YR 4/4) moist; massive; very hard, firm, slightly sticky and slightly plastic; few fine roots; few very fine tubular pores; 20 percent gravel; common medium faint flecks of calcium carbonate, slightly effervescent; slightly alkaline (pH 7.6); clear wavy boundary. (8 to 15 inches thick)
3C--44 to 60 inches; reddish brown (5YR 4/4) very gravelly sandy clay loam, dark reddish brown (5YR 3/4) moist; massive; very hard, firm, slightly sticky and slightly plastic; 35 percent gravel; slightly alkaline (pH 7.7).
TYPE LOCATION: Navajo County, Arizona; about 2.1 miles east of the Aripine Post Office on Arizona Highway 160 on the north side of the road, near the east 1/4 corner of section 12, T.11 N., R.18 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. Aridic ustic soil moisture regime.
Soil temperature: 47 to 59 degrees F.
Rock fragments: 0 to 35 percent gravel and cobble, and 0 to 15 percent stones
Hue: 5YR, 7.5YR, 10YR
Value: 3 through 5 dry, 2 or 3 moist
Chroma: 1 through 3, dry or moist
Reaction: moderately acid or neutral
Bt or Btk horizons
Hue: 2.5YR, 5YR, 7.5YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 2 through 6 dry, 2 through 8 moist
Calcium carbonate: none to less than 15 percent calcium carbonate equivalent as segregated masses, flecks or filaments
Reaction: neutral to moderately alkaline
Bk or C horizon
Hue: 5YR, 7.5YR, 10YR
Value: 4 through 6 dry, 3 through 6 moist
Chroma: 2 through 6 dry, 2 through 8 moist
Calcium carbonate: less than 15 percent calcium carbonate equivalent as segregated masses, flecks or disseminated
Reaction: slightly or moderately alkaline
A buried argillic horizon is present at depths greater than 40 inches in some pedons.
COMPETING SERIES: These are the Bethune (CO), Blackpipe (SD), Boneek (SD), Boquillas (AZ), Chapin (CO), Collbran (CO), Collide (CO), Emigrant (WY), Huggins (SD), Kube (SD), Leyden (CO), Loma (CO), Nuncho (WY), Nunn (CO), Querc (WY), Raku (CO), Rednun (CO), Richfield (KS), Ryus (KS), Savo (SD), Standley (CO), Thunderbird (AZ), Weld (CO), and Wormser (CO) series. Bethune, Blackpipe, Boquillas, Chapin, Emigrant, Huggins, Leyden, Querc, Thunderbird and Wormser soils have bedrock at depths of 20 to 40 inches. Boneek, Loma, Richfield and Savo soils contain less than 15 percent fine sand or coarser in the control section. Collbran soils imply they contain more than 15 percent calcium carbonate equivalent. Collide and Rednun soils have hues of 2.5YR or 5YR in the control section. Kube soils have bedrock at depths of 40 to 60 inches. Nuncho soils are moist in the moisture control section during April, May and June. Nunn soils have soil temperatures of 47 to 48 degrees F. and are moist in the moisture control section during May and June. Rednun soils have an early spring rainfall component. Ryus soils are calcareous throughout. Sofia soils have soil temperatures of 48 to 50 degrees F. Standley soils have hue of 10YR or yellower in the argillic horizon. Weld soils average less than 15 percent rock fragments below the Bt horizon..
GEOGRAPHIC SETTING: Showlow soils are on fan terraces, hills and plateaus. Elevations are 4,200 to 7,000 feet. Slopes range from 0 to 50 percent. The soils formed in mixed gravelly alluvium and colluvium from pyroclastics, basalt, sandstone, sandy shale, limestone, and granite. The climate is continental. The mean annual precipitation ranges from 14 to 18 inches, occurring as summer thunderstorms and winter rain and snow. The mean annual air temperature is 45 to 57 degrees F. The frost-free period is 120 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Ashfork, Boquillas, and Thunderbird soils and the Cabezon, Cross, Seligman, and Springerville soils. Cabezon and Cross soils have a lithic contact at a depth of less than 20 inches. Seligman soils have a paralithic contact at a depth of less than 20 inches. Springerville soils have intersecting slickensides.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; slow or very slow permeability.
USE AND VEGETATION: Used for livestock grazing, wildlife habitat and fuelwood production. Vegetation is pinon pine, Utah, juniper, blue grama, junegrass, bottlebrush squirreltail, Arizona fescue, mountain brome, mountain muhly, and western wheatgrass.
DISTRIBUTION AND EXTENT: Central and northern Arizona. The series is extensive. MLRAs 38 and 39.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Navajo County, Arizona; Holbrook-Showlow Area; 1962.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from 0 to 12 inches (A1, A2, 2Bt1 horizons)
Argillic horizon - the zone from 3 to 31 inches (2Bt1, 2Bt2, 2Btk horizons)
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006.
Revised for the correlation of AZ675, 5/2009, WWJ