LOCATION POPCORN AZEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, carbonatic, thermic Aridic Lithic Ustorthents
TYPICAL PEDON: Popcorn very gravelly clay loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 3 inches; brown (7.5YR 5/3) very gravelly clay loam, brown (7.5YR 4/3), moist; 32 percent clay; weak fine subangular blocky parting to moderate fine and medium granular structure; soft, very friable, moderately sticky and moderately plastic; common very fine and fine roots; common very fine and fine and common medium pores; 35 percent gravel and 5 percent cobbles comprised of limestone; violently effervescent, 44 percent calcium carbonate equivalent; moderately alkaline (pH 8.4); clear wavy boundary. (1 to 8 inches thick)
AC--3 to 13 inches; brown (7.5YR 5/2) very gravelly clay loam, brown (7.5YR 4/2), moist; 34 percent clay; moderate medium and coarse subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common very fine and fine and common medium roots; common very fine and fine and few medium pores; 45 percent gravel and 5 percent cobbles comprised of limestone; violently effervescent, 44 percent calcium carbonate equivalent; strongly alkaline (pH 8.6); clear wavy boundary. (4 to 16 inches thick)
R--13 to 60 inches; limestone bedrock.
TYPE LOCATION: Gila County, Arizona; located about 1,490 feet north and 890 feet west of the southeast corner of Section 11, Township 4N, Range 20E; Latitude: 33 degrees, 42 minutes, 9.0 seconds N; Longitude: 110 degrees, 13 minutes, 23.8 seconds W. NAD83; Topographic quadrangle: Forks Butte, Arizona.
RANGE IN CHARACTERISTICS:
Soil moisture - Intermittently moist in some part of the soil moisture control section during July-September and December-March. Driest during May and June. Aridic ustic soil moisture regime.
Soil temperature - 59 to 64 degrees F.
Particle-size control section (weighted average)
Clay content: 20 to 35 percent
Rock Fragments: 35 to 70 percent
Calcium carbonate equivalent: more than 40 percent based on whole soil
less than 20 mm
Depth to bedrock: 4 to 20 inches
Organic matter content: 0.5 to 3 percent
Reaction: slightly alkaline to strongly alkaline (pH 7.4-8.8)
A horizon
Hue: 7.5YR, 10YR
Value: 4 to 7 dry, 3 to 5 moist
Chroma: 2 to 3, dry or moist
Texture: loam, clay loam
Rock fragments: 25 to 70 percent by volume, mostly gravel
AC or C horizon
Hue: 7.5YR, 10YR
Value: 4 to 8 dry, 3 to 7 moist
Chroma: 2 to 4, dry or moist
Texture: loam, clay loam
Rock fragments: 25 to 70 percent by volume, mostly gravel
Some pedons contain a layer less than 3 inches thick of weathered bedrock above the lithic contact.
COMPETING SERIES: There are no competing series
GEOGRAPHIC SETTING:
Popcorn soils formed in residuum and slope alluvium derived from limestone and occur on hills and mountains. Elevation ranges from 4,000 to 6,000 feet. Slope ranges from 10 to 50 percent. Mean annual air temperature ranges from 57 to 62 degrees F. Mean annual precipitation ranges from 16 to 20 inches. Frost-free period ranges from 160 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Oversight and
Yarbam soils.
Oversight soils occur on lower foot slopes and alluvial fans and are very deep. Yarbam soils occur on similar positions and have a mollic epipedon.
DRAINAGE AND PERMEABILITY: Well drained; moderate or moderately slow permeability; medium or high runoff.
USE AND VEGETATION: These soils are used for livestock grazing and wildlife habitat. Present vegetation is one-seed juniper, pinyon, turbinella oak, Emory oak, manzanita, mountain mahogany, catclaw, agave, beargrass, sideoats grama, hairy grama, three-awn, and bullgrass.
DISTRIBUTION AND EXTENT: Central Arizona. The Popcorn series is of small extent. This soil occurs in LRR-D, MLRA 38.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: San Carlos Indian Reservation, Arizona, Parts of Gila and Graham Counties, (AZ675), 2009. The name comes from nearby Popcorn Canyon.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 3 inches (A horizon)
Lithic contact - the boundary at 13 inches (R horizon)
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006.