LOCATION BIGHAMS AZEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Ustic Haplocalcids
TYPICAL PEDON: Bighams very fine sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 2 inches; brown (7.5YR 5/4) very fine sandy loam, brown (7.5YR 4/2) moist; weak medium platy structure; soft, very friable, nonsticky and slightly plastic; common very fine roots; many very fine vesicular pores; slightly effervescent, 3 percent calcium carbonate equivalent; slightly alkaline; abrupt smooth boundary. (1 to 3 inches thick)
Bw1--2 to 9 inches; brown (7.5YR 5/4) fine sandy loam, brown (7.5YR 4/2) moist; weak fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; strongly effervescent, 7 percent calcium carbonate equivalent; slightly alkaline; clear smooth boundary. (3 to 8 inches thick)
Bw2--9 to 17 inches; brown (7.5YR 5/4) fine sandy loam, brown (7.5YR 4/4) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; violently effervescent, 11 percent calcium carbonate equivalent; slightly alkaline; abrupt smooth boundary. (4 to 10 inches thick)
2Bk1--17 to 23 inches; light brown (7.5YR 6/4) sandy clay loam, brown (7.5YR 5/4) moist; weak medium subangular blocky structure; hard, friable, slightly sticky and moderately plastic; many very fine roots; few very fine tubular pores; many fine irregular lime masses; violently effervescent, 25 percent calcium carbonate equivalent; slightly alkaline; clear smooth boundary. (3 to 7 inches thick)
2Bk2--23 to 35 inches; white (N 8/) sandy clay loam, pinkish white (7.5YR 8/2) moist; weak medium subangular blocky structure; very hard, friable, moderately sticky and moderately plastic; few very fine roots; few very fine tubular pores; many fine irregular lime masses and filaments; violently effervescent 30 percent calcium carbonate equivalent; slightly alkaline; abrupt smooth boundary. (9 to 12 inches thick)
3Cr--35 to 53 inches; partially weathered sandstone and mudstone with few very fine roots oriented along plates.
TYPE LOCATION: Navajo County, Arizona; about 3 miles south-southwest of Keams Canyon; about 500 feet east and 2800 feet south of the northwest corner of sec. 3, T. 27 N., R. 20 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. Ustic aridic soil moisture regime.
Soil temperature - 52 to 54 degrees F.
Depth to paralithic contact - 20 to 40 inches
Depth to calcic horizon - 8 to 25 inches
Carbonates- 15 to 40 percent calcium carbonate equivalent as, lime masses and other secondary accumulations
Organic matter content - Averages more than 0.7 percent in the upper 15.7 inches
Reaction - Slightly alkaline or moderately alkaline
A horizon
Hue: 5YR, 7.5YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 to 6 dry, 2 to 6 moist
Calcium carbonate in A horizon is less than 5 percent
Bw horizon
Hue: 5YR, 7.5YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 to 6 dry, 2 to 6 moist
Calcium carbonate in the Bw horizon range from 5 to 12 percent
Bk horizon
Hue: N8/0, 5YR, 7.5YR
Value: 6 to 8 dry, 5 to 8 moist
Chroma: 1 to 4 dry, 2 to 4 moist
Texture: fine sandy loam, sandy clay loam
Calcium carbonate equivalent: 15 to 40 percent
COMPETING SERIES: These are Abra (AZ), Bowdish (CO), Copeman (WY), Creel (NM), Darvey (NM), Hernandez (NM), Honlu (UT), Kimera (CO), Numa (CO), Peachsprings (AZ), and Xenmack (NM) series. Abra, Copeman, Darvey, Hernandez, Honlu, Kimera, Peachsprings, and Numa soils are deep and very deep. Bowdish soils have a lithic contact at 20 to 40 inches. Xenmack soils contain 5 to 10 percent calcium carbonate equivalent. Creel, Kimera, and Numa soils attempt to reflect the effects of soil-forming agents unique to the Great Plains.
GEOGRAPHIC SETTING: Bighams soils are on undulating plateaus, hills, and hillslopes. These soils formed in eolian deposits over slope alluvium derived dominantly from interbedded sandstone and mudstone. Slope ranges from 1 to 8 percent. Elevation is 6300 to 6700 feet. The average annual precipitation is 10 to 14 inches, the average annual air temperature is 50 to 52 degrees F, and the frost-free period is 120 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Begay, Mido, and Milok soils. Begay soils are coarse-loamy and lack calcic horizons. Mido soils are deep and sandy and on dunes. Milok soils are deep and coarse-loamy.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is medium. Permeability is moderate.
USE AND VEGETATION: Bighams soils are used for livestock grazing. The vegetation is mainly needle and thread, Indian ricegrass, blue grama, Stansbury cliffrose, scattered Utah juniper and pinyon.
DISTRIBUTION AND EXTENT: Northeastern Arizona. These soils are of minor extent. MLRA 35.
MLRA OFFICE RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Navajo County, Arizona, 1985. Hopi Area, Parts of Coconino and Navajo Counties.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 2 inches (A horizon)
Cambic horizon - the zone from 2 to 17 inches (Bw horizons)
Calcic horizon - the zone from 17 to 35 inches (2Bk horizons)
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006.
Name is from Bighams Lake on the Hopi Indian Reservation.
ADDITIONAL DATA: Lab data provided by BIA lab, Gallup, New Mexico, sample number S82017 AZ-123.
Updates and revisions for the correlation of Ft. Defiance (AZ715), February 26, 2008, DWD.