LOCATION BACOBI AZEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Typic Haplargids
TYPICAL PEDON: Bacobi fine sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 2 inches; light brown (7.5YR 6/4) fine sandy loam, brown (7.5YR 4/4) moist; weak thin platy structure; soft, very friable, nonsticky and nonplastic; common very fine roots; common very fine vesicular pores; strongly effervescent; moderately alkaline (pH 7.9); abrupt smooth boundary. (1 to 3 inches thick)
Bw--2 to 6 inches; brown (7.5YR 5/4) very fine sandy loam, brown (7.5YR 4/4) moist; weak medium subangular blocky structure; slightly hard, very friable, nonsticky and slightly plastic; many very fine roots; many very fine interstitial pores; strongly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (3 to 6 inches thick)
Bt--6 to 15 inches; brown (7.5YR 5/4) fine sandy loam, strong brown (7.5YR 4/6) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and plastic; many very fine roots; many very fine tubular pores; common clay bridging of sand grains, few thin patchy clay films on faces of peds; strongly effervescent; moderately alkaline (pH 7.9); clear smooth boundary. (4 to 11 inches thick)
Btk1--15 to 26 inches; mixed brown (7.5YR 5/4) and dark yellowish brown (10YR 4/4) sandy clay loam, brown (7.5YR 4/4) and dark yellowish brown (10YR 4/4) moist; moderate medium subangular blocky structure; hard, firm slightly sticky and plastic; common very fine roots; common very fine tubular pores; common clay bridging of sand grains, few thin patchy clay films on faces of peds; strongly effervescent, common fine rounded lime masses; moderately alkaline (pH 8.0); clear smooth boundary. (6 to 13 inches thick)
Btk2--26 to 33 inches; brown (7.5YR 5/4) fine sandy loam, brown (7.5YR 4/4) moist; weak medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; common very fine roots; few very fine tubular pores; common clay bridging of sand grains, few thin patchy clay films on faces of peds; strongly effervescent, common fine rounded lime masses; moderately alkaline (pH 8.1); clear smooth boundary. (5 to 9 inches thick)
Bk--33 to 36 inches; brown (7.5YR 5/4) fine sandy loam, brown (7.5YR 4/4) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; common very fine tubular pores; strongly effervescent, many very fine rounded lime masses; moderately alkaline (pH 8.2); abrupt smooth boundary. (1 to 5 inches thick)
2Cr--36 to 60 inches; interbedded sandstone and shale (gypsiferous mudstone).
TYPE LOCATION: Coconino County, Arizona on the Hopi Reservation; 2700 feet west and 2000 feet south of the northeast corner of section 29, T.28 N., R. 14 E.
RANGE IN CHARACTERISTICS:
Soil moisture - Intermittently moist in some part of the soil moisture control section in December-March and July-September. Driest during May and June. Typic aridic soil moisture regime.
Soil temperature - 53 to 59 degrees F.
Depth to bedrock - 20 to 40 inches
Control section - Clay content: 14 to 27 percent.
Rock fragments - Less than 10 percent pebbles
Calcium carbonate equivalent - 2 to 15 percent in any one horizon
Reaction - Moderately alkaline or strongly alkaline
Solum thickness - 20 to 40 inches
SAR- 2 to 6, but ranges from 1 to 10
A horizon
Hue: 7.5YR, 5YR
Value: 4, 5 or 6 dry, 4 or 5 moist
Chroma: 4 or 6, dry or moist
Bw horizon
Hue: 7.5YR, 5YR
Value: 5 dry, 4 moist
Chroma: 4 or 6, dry or moist
Texture: Fine sandy loam, very fine sandy loam, sandy clay loam (10 to 15 percent clay)
Bt horizon
Hue: 7.5YR, 10YR
Value: 4, 5, or 6 dry, 3, 4, or 5 moist
Chroma: 4 or 6, dry or moist
Texture: Fine sandy loam, sandy clay loam (ranges from 14 to 27 percent clay but averages more than 18 percent).
Bk horizon (when present)
Hue: 7.5YR, 10YR
Value: 4, 5, or 6 dry, 3, 4, or 5 moist
Chroma: 4 or 6, dry or moist
Texture: Fine sandy loam, sandy loam, sandy clay loam (14 to 27 percent clay)
COMPETING SERIES: These are the Frisite (WY), Grazane (AZ), Griffy (WY), Kiki (NM), Neiber (WY), Papoose (NV), Redlands (CO), Saddle (WY), and Starmountain (AZ) and Tijeras (NM) soils. Frisite, Griffy, Papose, Redlands, Starmountain and Tijeras soils are very deep. Kiki soils have a lithic contact within 40 inches. Neiber and Saddle soils have yellower hue and soil temperatures of 47 to 49 degrees F. Grazane soils average more than 27 percent clay in the control section.
GEOGRAPHIC SETTING: Bacobi soils are on plateaus. Slopes' are 1 to 7 percent. Elevations range from 4700 to 5900 feet. The soils formed in eolian deposits over slope alluvium derived from sedimentary rocks. The mean annual precipitation is 6 to 11 inches. Mean annual air temperature is 52 to 55 degrees F. The frost-free period is 165 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Jocity, Monue, Sheppard, and Tewa soils. These soils are very deep.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used mainly for livestock grazing and wildlife habitat. Vegetation is mainly galleta, alkali sacaton, Indian ricegrass, and shadscale
DISTRIBUTION AND EXTENT: Northern Arizona. The series is of small extent. MLRA 35.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona.
SERIES ESTABLISHED: Coconino County, Arizona; Soil survey of the Hopi Area, Parts of Coconino and Navajo Counties; 1985.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 3 inches (A horizon)
Argillic horizon - The zone from 6 to 33 inches (Bt, Btk1 and Btk2)
Paralithic contact - The boundary at 36 inches (2Cr horizon)
Classified according to Keys to Soil Taxonomy Ninth Edition, 2003
ADDITIONAL DATA: Gallup BIA Lab Data; Sample S82AZ0l7-l29