LOCATION TOPOCK AZEstablished Series
TAXONOMIC CLASS: Clayey, mixed, superactive, thermic, shallow Typic Haplargids
TYPICAL PEDON: Topock extremely gravelly sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 2 inches; reddish brown (5YR 5/3) extremely gravelly sandy loam, dark reddish brown (5YR 3/3) moist; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many fine irregular pores; 70 percent gravel; noneffervescent; neutral (pH 7.2); abrupt wavy boundary. (1 to 3 inches thick)
Bt1--2 to 5 inches; reddish brown (5YR 4/4) gravelly sandy clay, reddish brown (5YR 4/3) moist; moderate medium subangular blocky structure; very hard, very firm, very sticky and very plastic; common very fine roots; few fine tubular pores; common distinct clay films on faces of peds; 25 percent gravel; noneffervescent; neutral (pH 7.2); clear wavy boundary. (4 to 8 inches thick)
Bt2--5 to 12 inches; yellowish red (5YR 4/6) sandy clay, yellowish red (5YR 4/6) moist; strong medium subangular blocky structure; very hard, very firm, very sticky and very plastic; few very fine roots; few very fine tubular pores; common distinct clay films on faces of peds; 10 percent gravel; noneffervescent; slightly alkaline (pH 7.6); abrupt irregular boundary. (4 to 9 inches thick)
2Cr--12 to 23 inches; weathered granite; clear irregular boundary. (3 to 20 inches thick)
2R--23 inches; granite.
TYPE LOCATION: Mohave County, Arizona; located at a latitude of 34 degrees, 41 minutes, 05 seconds North and a longitude of 113 degrees, 43 minutes, 38 seconds west; 2,500 feet south and 2,000 feet west of the northeast corner of section 33, T. 16 N., R. 14 W.
RANGE IN CHARACTERISTICS:
Soil Moisture - Intermittently moist in some part of the soil moisture control section during December - February and for more than 20 days cumulative during July - September. Driest during May and June. Typic aridic soil moisture regime.
Depth to weathered bedrock: 10 to 20 inches
Depth to unweathered bedrock: 20 to 40 inches
Soil Temperature: 61 to 66 degrees F.
A horizon
Hue: 5YR, 7.5YR
Value: 5 or 6 dry, 3 or 4 moist
Chroma: 3 or 4, dry or moist
Bt horizon
Hue: 5YR, 7.5YR
Value: 4 through 6 dry, 3 or 4 moist
Chroma: 3 through 6, dry or moist
Texture: Clay, sandy clay (35 to 60 percent clay)
Rock fragments: 5 to 35 percent gravel
COMPETING SERIES: This is the Mutang (AZ) series. Mutang soils are moist in the soil moisture control section for less than 20 days cumulative from July to September.
GEOGRAPHIC SETTING: Topock soils are on hills and mountains. Slopes range from 5 to 35 percent. These soils formed in mixed igneous and metamorphic alluvium. Elevations range from 2,400 to 4,800 feet. The mean annual precipitation is 10 to 12 inches. The mean annual air temperature is 59 to 64 degrees F. The frost-free period is about 200 to 230 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cellar, Continental and Dona Ana soils. Cellar soils do not have argillic horizons. Continental and Dona Ana soils are very deep.
DRAINAGE AND PERMEABILITY: Well drained; very high runoff; slow permeability.
USE AND VEGETATION: Used for livestock grazing and wildlife habitat. Vegetation includes black grama, sideoats grama, desert needle grass, California juniper, broom snakeweed and turpentine bush.
DISTRIBUTION AND EXTENT: Western Arizona. This series is of moderate extent. MLRA is 40. The name is from a local community.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Mohave County, Arizona; Soil survey of Mohave County, Arizona, Southern Part; 2005.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 2 inches (A horizon)
Argillic horizon - the zone from 2 to 12 inches (Bt1, Bt2 horizons)
Paralithic contact - the boundary at 12 inches (2Cr horizon)
Lithic contact - the boundary at 23 inches (2R horizon)
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006.