LOCATION TAJO AZEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Petrocalcic Paleustolls
TYPICAL PEDON: Tajo gravelly loam-rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 3 inches; brown (10YR 5/3) gravelly loam, dark brown (10YR 3/3) moist; moderate medium platy and moderate fine granular structure; slightly hard, friable, slightly sticky and nonplastic; common very fine roots; many interstitial pores; 25 percent hard pebbles; very slightly effervescent; slightly alkaline (pH 7.6); abrupt smooth boundary. (2 to 4 inches thick.)
B1--3 to 14 inches; brown (10YR 5/3) clay loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; hard, friable, sticky and plastic; few very fine roots; many very fine interstitial and common very fine tubular pores; 10 percent hard pebbles; slightly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (8 to 12 inches thick.)
B2--14 to 28 inches; grayish brown (10YR 5/2) clay loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; hard, friable, sticky and plastic; very few very fine roots; common very fine interstitial pores; 5 percent hard pebbles, 5 percent hard cobbles; strongly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (10 to 20 inches thick.)
Bk--28 to 40 inches; white (10YR 8/1) weakly cemented, lime fragments and gravel, very pale brown (10YR 8/3) moist; massive; violently effervescent; moderately alkaline (pH 8.4); abrupt wavy boundary. (0 to 14 inches thick.)
2Bkm--40 to 46 inches; white (10YR 8/1) indurated hardpan cemented with lime, very pale brown (10YR 8/2) moist; massive; violently effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (4 to 12 inches thick.)
2Ck--46 to 60 inches; white (10YR 8/1) weakly to strongly cemented cinder, very pale brown (10YR 8/2) moist; massive; violently effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (8 to 20 inches thick.)
TYPE LOCATION: Yavapai County, Arizona. SE 1/4 SE 1/4, sec. 3, T. 20 N., R. 6 W.
RANGE IN CHARACTERISTICS:
Depth to Bkm horizon: 20 - 40 inches
Depth to bedrock: 60 - 70 inches
Soil moisture: Intermittently moist in some parts of July-September, and December-February. Aridic ustic moisture regime.
Air temperature: 47 - 59 degrees F.
Rock fragments: 10 - 30 percent hard gravel
A horizon
Hue: 7.5YR or 10YR
Value: 3 to 5 dry, 3 moist
Chroma: 2 or 3 moist or dry
Texture: gravelly loam, gravelly clay loam (15 to 35 percent clay)
Reaction: Neutral to slightly alkaline
B horizon
Hue: 7.5YR or 10YR
Value: 4 or 5 dry, 2 to 4 moist
Chroma: 2 or 3 moist or dry
Texture: clay loam, gravelly clay loam (18 - 35 percent clay)
Reaction: slightly to moderately alkaline
Bk horizon
Hue: 10YR
Value: 8 dry or moist
Chroma: 1 or 2 dry, 2 or 3 moist
Texture: Weakly to strongly indurated solum and cinders
Reaction: Moderately to strongly alkaline
COMPETING SERIES: This is the Scorup series. Scorup soils have hue of 5YR and have a fine sandy loam argillic horizon.
GEOGRAPHIC SETTING: The Tajo soils are on fan terraces with slope gradients of 0 to 15 percent. Elevations are 5,000 to 6,000 feet. They formed in pyroclastics and basalt. The climate is semiarid. The average annual precipitation is 12 to 14 inches and occurs mainly as summer thunderstorms and as rain and snow during the winter months. The average annual temperature is about 53 degrees F. Frost-free season is 120 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Apache, Springerville, Cabezon, Cross and Thunderbird series. The Apache soils are shallow to bed rock and lack a petrocalcic horizon. Springerville soils are deep fine- textured soils that crack widely and deeply upon drying. Cabezon and Cross soils are shallow to bedrock. Thunderbird soils lack a petrocalcic horizon.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is medium. Permeability of the soil is moderately slow.
USE AND VEGETATION: These soils are used as range land. The principal vegetation is blue grama, tobosa, cholla cactus, saltbush, winterfat, wolf berry and Russian thistle.
DISTRIBUTION AND EXTENT: North central Arizona. The series is of moderate extent. MLRAs 38 & 35.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Yavapai County, Arizona, Western part, 1971.