LOCATION BOQUILLAS AZEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aridic Argiustolls
TYPICAL PEDON: Boquillas gravelly loam - grazeable woodland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 3 inches; brown (7.5YR 5/2) gravelly loam, dark brown (7.5YR 3/2) moist; moderate thin platy structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; common fine vesicular pores; 20 percent hard gravel; slightly alkaline (pH 7.4); clear smooth boundary. (2 to 4 inches thick)
A2--3 to 6 inches; brown (7.5YR 5/2) clay loam, dark brown (7.5YR 3/2) moist; weak fine and medium subangular blocky structure; slightly hard, friable, sticky and plastic; common very fine, fine and few medium roots; few fine interstitial pores; 10 percent hard gravel; slightly alkaline (pH 7.6); abrupt smooth boundary. (3 to 8 inches thick)
2Bt1--6 to 12 inches; dark reddish gray (5YR 4/2) gravelly clay, dark reddish brown (5YR 3/2) moist; moderate fine and medium subangular blocky structure; hard, firm, sticky and plastic; common fine and coarse roots; few very fine interstitial pores; 25 percent hard gravel; common faint clay films on faces of peds; slightly alkaline (pH 7.6); clear smooth boundary. (6 to 10 inches thick)
2Bt2--12 to 19 inches; dark reddish brown (5YR 3/3) gravelly clay, dark reddish brown (5YR 3/3) moist; strong medium and coarse prismatic structure parting to moderate very fine and fine subangular blocky; very hard, very firm, very sticky and very plastic; common very fine, few fine and coarse roots; few very fine interstitial pores; 15 percent hard gravel; few faint clay films on faces of peds; common pressure faces; slightly alkaline (pH 7.6); clear smooth boundary. (5 to 8 inches thick)
2Bt3--19 to 23 inches; dark reddish brown (5YR 3/4) gravelly clay, dark reddish brown (5YR 3/4) moist; strong medium and coarse prismatic structure parting to strong medium subangular blocky; very hard, very firm, very sticky and very plastic; few very fine, fine and coarse roots; few very fine interstitial pores; few faint clay films on faces of peds; 25 percent gravel; common pressure faces; slightly alkaline (pH 7.6); clear wavy boundary. (2 to 4 inches thick)
3Bk--23 to 38 inches; reddish brown (5YR 4/4) very gravelly clay loam, dark reddish brown (5YR 3/4) moist; massive; very hard, friable, sticky and plastic; few fine and medium roots; 40 percent gravel and 10 percent cobble, calcium carbonate coated; many soft calcium carbonate masses; strongly effervescent; slightly alkaline (pH 7.8); abrupt wavy boundary. (2 to 16 inches thick)
4Cr--38 inches; hard siliceous tuff; can be dug with a spade after soaking with water.
TYPE LOCATION: Coconino County, Arizona; about 2 miles north of Mount Floyd; SE 1/4, NW 1/4 of section 33, T.24 N., R.4 W.
RANGE IN CHARACTERISTICS:
Soil moisture: Intermittently moist in some part of the soil moisture control section during July-August and December-January. Driest during May and June. Aridic ustic soil moisture regime.
Soil Temperature: 52 to 56 degrees F.
Rock fragments: 5 to 35 percent gravel and cobble
Depth to bedrock: 20 to 40 inches
A horizon
Hue: 7.5YR, 10YR
Value: 4 or 5 dry
Chroma: 2 through 4, dry or moist
Reaction: neutral or slightly alkaline
Bt horizon
Hue: 5YR, 7.5YR
Value: 4 through 6 dry, 3 or 4 moist
Chroma: 2 through 4, dry or moist
Texture: clay loam, clay (35 to 45 percent clay)
Reaction: neutral or slightly alkaline
Bk horizon
Hue: 5YR, 7.5YR
Value: 4 through 6 dry, 3 or 4 moist
Texture: clay loam, clay (30 to 40 percent clay)
Calcium carbonate equivalent: less than 15 percent
COMPETING SERIES: These are the Bethune (CO), Blackpipe (SD), Boneek (SD), 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), Showlow (AZ), Standley (CO), Thunderbird (AZ), Weld (CO) and Wormser (CO) series. Chapin and Thunderbird soils have a lithic contact at depths of 20 to 40 inches. Boneek, Collbran, Collide, Kube, Loma, Nuncho, Nunn, Querc, Raku, Rednun, Richfield, Savo, Showlow, Sofia, Standley, and Weld soils do not have bedrock at depths less than 40 inches. Chapin and Wormser soils formed from sandstone and in addition, Bethune, Wormser and Leyden soils have hue of 10YR or yellower. Ryus soils are calcareous throughout. Blackpipe, Emigrant and Huggins soils are moist in the soil moisture control section during May and June.
GEOGRAPHIC SETTING: Boquillas soils are on plateaus and mesas at elevations of 5,800 to 6,300 feet. They formed in alluvium from basaltic, pumiceous, and siliceous tuff; rhyodacite, dacite, and rhyolite. Slopes range from 1 to 15 percent. Mean annual precipitation is 14 to 18 inches. The mean annual air temperature is 50 to 54 degrees F. The frost-free period ranges is 120 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cabezon, Faraway, Lynx, Seligman and Springerville soils and the competing Ashfork and Thunderbird soils. Cabezon, Faraway and Seligman soils have a lithic or paralithic contact at depths less than 20 inches. Faraway, Lynx, and Springerville soils do not have argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; slow permeability.
USE AND VEGETATION: Boquillas soils are used for livestock grazing, fuelwood production and wildlife habitat. Vegetation is mainly oneseed juniper, blue grama, sideoats grama, sand dropseed, bottlebrush squirrel tail, algerita, and broom snakeweed.
DISTRIBUTION AND EXTENT: North central Arizona. The series is not extensive. MLRA 39.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Coconino County, Arizona; Soil survey of Coconino County Area, Arizona, Central Part: 1980.
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 6 to 23 inches (2Bt1, 2Bt2, 2Bt3 horizons)
Paralithic contact - The boundary at 38 inches (4Cr horizon)