LOCATION HATKNOLL AZEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Typic Calciargids
TYPICAL PEDON: Hatknoll silty clay loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 3 inches; brown (7.5YR 4/3) silty clay loam, dark brown (7.5YR 3/4) moist; weak thin platy structure; hard, firm, sticky and plastic; common very fine roots; few very fine tubular pores; 5 percent gravel; noneffervescent; moderately alkaline (pH 8.0); abrupt smooth boundary. (2 to 5 inches thick)
Bt1--3 to 12 inches; brown (7.5YR 4/4) silty clay, dark brown (7.5YR 3/4) moist; strong fine prismatic structure parting to strong fine subangular blocky; very hard, firm, very sticky and very plastic; common very fine roots; many very fine tubular pores; common thin clay films on ped faces and in pores; 5 percent gravel; noneffervescent; moderately alkaline (pH 8.2); clear wavy boundary. (3 to 10 inches thick)
Bt2--12 to 20 inches; brown (7.5YR 4/4) silty clay, dark brown (7.5YR 3/4) moist; strong fine subangular blocky structure; very hard, firm, very sticky and very plastic; common very fine roots; many very fine tubular pores; common moderately thick clay films on ped faces and in pores; 5 percent gravel; noneffervescent; moderately alkaline (pH 8.2); clear wavy boundary. (6 to 12 inches thick)
Bt3--20 to 25 inches; reddish brown (5YR 4/4) gravelly silty clay, reddish brown (5YR 4/4) moist; strong fine subangular blocky structure; very hard, firm, very sticky and very plastic; few very fine roots; many very fine tubular pores; common thin clay films on ped faces and in pores; 20 percent gravel; noneffervescent; moderately alkaline (pH 8.2); clear wavy boundary. (0 to 9 inches thick)
2Bk1--25 to 36 inches; light brown (7.5YR 6/4) loam, brown (7.5YR 5/4) moist; moderate fine subangular blocky structure with discontinuous areas of weak thin platy; very hard, friable, slightly sticky and slightly plastic; few very fine roots; many very fine tubular pores; violently effervescent, few fine soft lime masses; moderately alkaline (pH 8.4); clear smooth boundary. (6 to 15 inches thick)
2B--36 to 60 inches; light brown (7.5YR 6/4) loam, brown (7.5YR 5/4) moist; weak fine subangular blocky structure with discontinuous areas of weak thin platy; very hard, friable, slightly sticky and slightly plastic; few very fine roots; many very fine tubular pores; violently effervescent, lime disseminated; moderately alkaline (pH 8.4).
TYPE LOCATION: Mohave County, Arizona; about 19 miles south of Colorado City; 1,000 feet south and 300 feet east of the northwest corner of section 33, T. 38 N., R. 7 W.
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. Typic aridic soil moisture regime.
Soil Temperature: 57 to 59 degrees F.
Rock Fragments: less than 15 percent
Depth to Calcic: 20 to 30 inches
A horizon
Hue: 5YR, 7.5YR
Value: 4 through 6 dry, 3 through 5 moist
Chroma: 3 or 4, dry or moist
Bt horizon
Hue: 5YR, 7.5YR
Value: 4 through 6 dry, 3 through 5 moist
Chroma: 4 or 6, dry or moist
Bk and B horizon
Hue: 5YR, 7.5YR
Value: 6 through 8 dry, 5 or 6 moist
Chroma: 4 or 6, dry or moist
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Hatknoll soils are on fan terraces at elevations of 4,700 to 5,000 feet. They formed in alluvium from basalt and pyroclastics. Slopes range from 1 to 10 percent. Mean annual precipitation is 7 to 11 inches. The mean annual air temperature is about 55 to 57 degrees F. The frost-free period is 165 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brinkerhoff, Clayhole, Grieta, Jocity, Kinan and Moab series. Brinkerhoff and Clayhole soils have horizons high in gypsum. Grieta and Jocity soils are fine-loamy. Kinan soils are coarse-loamy. Moab soils are loamy-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; slow or medium runoff; slow permeability.
USE AND VEGETATION: Used mainly for livestock grazing. Vegetation is mainly galleta, green rabbitbrush, snakeweed and fourwing saltbush.
DISTRIBUTION AND EXTENT: Northern Arizona. MLRA is 35. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Mohave County, Arizona; Soil survey of Mohave County Area, Arizona, Northeastern Part, and Part of Coconino County; 1992.
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 3 to 25 inches (Bt1, Bt2, Bt3 horizons)
Calcic horizon - The zone from 25 to 36 inches (2Bk horizon)
Classified according to Soil Taxonomy Second Edition, 1999
The classification was changed from fine, smectitic, mesic Typic Haplargids to fine, smectitic, mesic Typic Calciargids in 2003