LOCATION SPUDROCK AZEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Typic Haplustepts
TYPICAL PEDON: Spudrock very flaggy sandy loam - woodland. (Colors are for dry soil unless otherwise noted.)
Oi--1 to 0 inches; slightly decomposed forest litter of pine needles and oak leaves.
A--0 to 5 inches; brown (10YR 5/3) very flaggy sandy loam, dark brown (10YR 3/3) moist; moderate fine granular structure; slightly hard, very friable, nonsticky and nonplastic; common very fine roots; common fine tubular pores; 25 percent flagstones and 10 percent channers; neutral (pH 6.8); clear smooth boundary. (1 to 6 inches thick)
Bw--5 to 17 inches; pale brown (10YR 6/3) very channery fine sandy loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; common medium roots; common medium tubular pores; few thin dark brown (10YR 3/3) organic coats lining pores and on faces of peds; 40 percent channers and gravel; moderately acid (pH 6.0); gradual smooth boundary. (10 to 25 inches thick)
BC--17 to 24 inches; light yellowish brown (10YR 6/4) very channery fine sandy loam, dark yellowish brown (10YR 4/4) moist; massive; slightly hard, very friable, slightly sticky and nonplastic; common medium roots; common medium tubular pores; 35 percent channers and gravel; slightly acid (pH 6.2); abrupt smooth boundary. (0 to 19 inches thick)
2Cr--24 to 60 inches; variegated very pale brown (10YR 7/3) and yellow (10YR 7/6) partially weathered gneiss (grus), brown (10YR 5/3) and yellowish brown (10YR 5/6) moist; few fine roots in fractures.
TYPE LOCATION: Pima County, Arizona; 1800 feet north and 2450 feet east of the southwest corner of section 24, T.14 S., R.17 E. in the Saguaro National Monument-Eastern part.
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 ustic soil moisture regime.
Soil temperature - 47 to 59 degrees F.
Rock fragments - 35 to 70 percent gravel, channers and flagstones
Depth to bedrock - 20 to 40 inches
Organic matter content - Greater than 1 percent in the surface
Reaction - Moderately acid to neutral
A horizon
Hue: 10YR, 7.5YR
Value: 3 through 6 dry, 2 through 5 moist
Chroma: 2 through 6, dry or moist
Bw horizon
Hue: 10YR, 7.5YR
Value: 5, 6, or 7 dry, 4, 5, or 6 moist
Chroma: 2 through 6, dry or moist
Texture: Sandy loam, fine sandy loam, loamy fine sand (5 to 20 percent clay)
BC horizon
Hue: 10YR, 7.5YR
Value: 5, 6, or 7 dry, 4, 5, or 6 moist
Chroma: 2 through 6, dry or moist
Texture: Sandy loam, fine sandy loam (5 to 20 percent clay)
An E horizon is present in some pedons.
COMPETING SERIES: There are no competitors.
GEOGRAPHIC SETTING: Spudrock soils are on hills and mountains. Slopes range from 15 to 85 percent. They formed in slope alluvium from gneiss and schist. Elevation ranges from 5300 to 8700 feet. The mean annual precipitation is 20 to 30 inches occurring as summer thunderstorms and winter rain and snow. Mean annual air temperature is 45 to 57 degrees F. The frost-free period is 140 to 195 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cortaro, Lemmon and Far soils. Cortaro soils are shallow. Lemmon soils have argillic horizons. Far soils have a mollic epipedon and a lithic contact.
DRAINAGE AND PERMEABILITY: Well drained; rapid runoff; moderately rapid permeability.
USE AND VEGETATION: Used mainly for timber production, recreation, wildlife habitat and watershed. Vegetation is mainly silverleaf oak, Arizona white oak, Mexican pinyon, alligator juniper and ponderosa pine with an understory of manzanita, bullgrass, prairie junegrass, Fenders ceonothus, datil yucca, mountain muhly, muttongrass, skunkbush sumac, wax current and sacahista.
DISTRIBUTION AND EXTENT: Southeastern Arizona. This soil is moderately extensive in the higher mountains. MLRA is 41.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Pima County, Arizona; Soil survey of Pima County, Arizona, Eastern Part; 1985.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 5 inches (A horizon)
Cambic horizon - The zone from 5 to 17 inches (Bw horizon)
Paralithic contact - The boundary at 24 inches (2Cr horizon)