LOCATION PEARCE AZEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, calcareous, thermic Lithic Torriorthents
TYPICAL PEDON: Pearce extremely stony loam rangeland and wildlife habitat. (Colors are for dry soil unless otherwise noted.)
A--0 to 2 inches; yellowish brown (10YR 5/4) extremely stony loam, dark yellowish brown (10YR 4/4) moist; weak fine granular structure; slightly hard, very friable, nonsticky and nonplastic; few very fine roots; many fine irregular pores; 25 percent gravel, 20 percent cobble, 20 percent stone; strongly effervescent, 30 percent calcium carbonate equivalent; moderately alkaline (pH 8.0); abrupt smooth boundary. (1 to 3 inches thick)
Bk--2 to 7 inches; yellowish brown (10YR 5/4) extremely stony loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; few very fine roots; few very fine tubular pores; 25 percent gravel, 20 percent cobble, 20 percent stone; strongly effervescent, 34 percent calcium carbonate equivalent; lime coats and pendants on underside of some rock fragments; moderately alkaline (pH 8.0); abrupt smooth boundary. (3 to 19 inches thick)
2R--7 inches: limestone.
TYPE LOCATION: Located at a latitude of 36 degrees, 03 minutes, 06 seconds north and a longitude of 114 degrees, 01 minutes, 34 seconds west. About 1,900 feet south and 1,400 feet east of the northwest corner of section 29, T. 31 N., R. 16 W. Gila and Salt River Base Meridian.
RANGE IN CHARACTERISTICS:
Soil moisture - Intermittently moist in some part of the soil moisture control section during December through February and for less than 20 cumulative days during July - September. Driest during May and June. Typic aridic soil moisture regime.
Rock fragments: 15 to 30 percent stone, 15 to 30 percent cobble and 20 to 35 percent gravel on the surface and in the profile.
Clay content: 7 to 18 percent
Depth to bedrock: 4 to 20 inches
Organic matter: less than 1 percent
Calcium carbonate equivalent: 5 to 35 percent. Does not qualify as a calcic.
Reaction: slightly or moderately alkaline
A and Bk horizons
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 or 4, dry or moist
Texture: loam, sandy loam
COMPETING SERIES: These are the Akela (NM), Beach (TX), Chatticup (NV), Dalvord (CA), Galehills (NV), Haleburu (NV), Hindu (AZ), Hulda (AZ), Noble Pass (CA), Paintrocks (CA), Razorback (AZ), Sutra (AZ), Tecopa (CA), Terlingua (TX) and Upspring (CA) soils. Akela soils are usually dry from October through May. Beach soils have hue of 2.5YR or 5YR. Chatticup soils contain 60 to 89 percent rock fragments- with 25 to 40 percent in the 2 to 5 mm fraction and have formed from granite. Dalvord do not have a required Bk horizon with visible accumulations of calcium carbonate and have formed in granite. Galehills soils are drier in the soil moisture control section due to a mean annual precipitation of 3 to 5 inches and formed in sandstone conglomerate. Haleburu soils are strongly alkaline in the lower part and formed in volcanic bedrock. Hindu soils are moist for more than 20 cumulative days during July-September. Hulda soils are dominantly coarse and very coarse in the sand fraction. Noblepass soils are dry in the summer and formed in andesite and rhyolite. Paintrocks soils are less than 3 inches deep to a paralithic contact and formend in granite. Razorback have rock fragments that are dominated by cobble and stone and formed in extrusive igneous rock. Sutra soils have less than 60 percent rock fragments in the particle size control section and are dominated by gravel . Terlingua soils are dry in the winter and formed from igneous rock. Tecopa and Upspring soils are usually dry from June through November, Tecopa soils formed in quartz and schist and Upspring soils formed in extrusive igneous rock.
GEOGRAPHIC SETTING: Pearce soils are on mesas, hills and mountains at elevations of 1,600 to 3,000 feet. Slopes range from 4 to 75 percent. These soils formed in alluvium and colluvium from limestone. The mean annual precipitation is 6 to 12 inches. The mean annual air temperature is 57 to 70 degrees F. The frost-free period is 200 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Detrital, Greyeagle, Huevi, Skelon and Tyro soils. Detrital and Huevi soils are very deep. Tyro and Greyeagle soils have a hardpan above 20 inches. Skelon soils have a hardpan at 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; medium to very high runoff; moderate permeability.
USE AND VEGETATION: Used for recreation and wildlife habitat. Vegetation includes white bursage, Nevada Mormon tea, creosote bush, fluff grass and big galleta.
DISTRIBUTION AND EXTENT: Northwestern Arizona. Pearce soils are of moderate extent. MLRA is 30.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Mohave County, Arizona; Soil survey of Mohave County, Arizona, Central Part; 2005. Name derived from Pearce Ferry on the Colorado River.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 2 inches (A horizon)
Entisol feature - The absence of diagnostic subsurface horizons
Lithic contact - The boundary at 7 inches (2R horizon)
Classified according to Keys to Soil Taxonomy Ninth Edition, 2003.