LOCATION OTROIZO AZEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, mixed, thermic Aridic Ustorthents
TYPICAL PEDON: Otroizo stony sandy loam - recreation and wildlife habitat. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 1 inch; pine and oak leaf litter.
Oe--1 to 2 inches; very dark grayish brown (10YR 3/2) decomposed pine and leaf litter, black (10YR 2/1) moist; 30 percent rubbed fiber; noneffervescent; strongly acid (pH 5.4); abrupt smooth boundary. (Combined thickness of the O horizons is 0 to 4 inches)
A--2 to 6 inches; pale brown (10YR 6/3) gravelly sandy loam, brown (10YR 4/3) moist; moderate medium and strong fine granular structure; soft, very friable, slightly sticky and nonplastic; common very fine and few fine and medium roots; many very fine and few fine, medium and coarse irregular pores; 15 percent gravel, 5 percent cobble, 5 percent stone; noneffervescent; strongly acid (pH 5.4); clear smooth boundary. (2 to 6 inches thick)
C--6 to 62 inches; somewhat variegated pinkish white (7.5YR 8/2) to pinkish gray (7.5YR 6/2) very stony loamy sand, dark gray (7.5YR 4/1) moist; massive; soft, very friable, nonsticky and nonplastic; common very fine, fine, medium and few coarse roots; many very fine, common fine and few medium and coarse irregular pores; 15 percent gravel, 20 percent cobble, 15 percent stone and boulder; noneffervescent; slightly acid (pH 6.4).
TYPE LOCATION: Chiricahua National Monument; located at a latitude of 32 degrees, 22 seconds North and longitude of 109 degrees, 20 minutes, 55 seconds West.
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. Aridic ustic soil moisture regime.
Soil temperature: 59 to 64 degrees F.
Organic matter: 0.1 to 0.5 percent in the particle-size control section
Rock fragments: 45 to 60 percent, dominated by cobble, stone and boulders
Clay content: averages 4 to 8 percent in the particle-size control section
Reaction: strongly acid or slightly acid
A horizon
Hue: 7.5YR, 10YR
Value: 4, 5 or 6 dry, 3 or 4 moist
Chroma: 2 or 3, dry or moist
C horizon
Hue: 7.5YR, 10YR
Value: 6 through 8 dry, 4 or 5 moist
Chroma: 1 or 2, dry or moist
Texture: sand or loamy sand
The content of boulder and stone mask any recognizable horizonation
COMPETING SERIES: This is the Shamizo (AZ) series. Shamizo soils have more than 65 percent coarse fragments in the particle-size control section, are neutral or slightly alkaline throughout and are subject to flooding.
GEOGRAPHIC SETTING: Otroizo soils are on stream terraces at elevations of 5,400 to 5,800 feet. Slopes range from 3 to 5 percent. These soils formed in stream alluvium from rhyolite tuff. The mean annual precipitation is 20 to 23 inches and occurs as thunderstorms during July to September and as gentle rains during December to February. The mean annual air temperature is 58 to 62 degrees F. The frost-free period is 160 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the Massai soils. Massai soils have more than 8 percent clay in the particle-size control section.
DRAINAGE AND PERMEABILITY: Excessively drained; slow runoff; rapid permeability.
USE AND VEGETATION: Used for recreation and wildlife habitat. Vegetation includes silverleaf oak, netleaf oak, Chihuahua pine, Arizona cypress, Arizona madrone and bull grass.
DISTRIBUTION AND EXTENT: Southern Arizona. Otroizo soils are of limited extent. This soil occurs in LRR-D, MLRA 41.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Cochise County, Arizona. Soil survey of Chiricahua National Monument; 1997.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 4 inches (A horizon)
Entisol feature - The absence of diagnostic subsurface horizons
Classified according to Soil Taxonomy Second Edition, 1999.