LOCATION COCOCO                  AZ

Established Series
Rev. JMH/MJA
02/2025

COCOCO SERIES

The Cococo series consists of very deep, well drained soils that formed in broadly stratified alluvium derived predominantly from dolomite. Cococo soils are on washes and stream terraces between structural benches. Slopes range from 0 to 3 percent. Mean annual precipitation is about 18 inches and the mean annual temperature is about 54 degrees F.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Torrifluventic Haplustepts

TYPICAL PEDON: Cococo-Maryrussell complex, 0 to 3 percent slopes (Colors are for dry soil unless otherwise noted.)

A--0 to 2 inches, brown (7.5YR 5/3) loam, brown (7.5YR 4/3) moist; weak fine granular structure; loose, friable; strongly effervescent; slightly alkaline; clear smooth boundary.

BA--2 to 10 inches, brown (7.5YR 5/3) silt loam, brown (7.5YR 4/3) moist; weak very fine subangular blocky structure; soft, friable; strongly effervescent; slightly alkaline; gradual wavy boundary.

Bt1--10 to 20 inches, brown (7.5YR 5/3) loam, brown (7.5YR 4/3) moist; moderate fine subangular blocky; slightly hard, firm; violently effervescent; moderately alkaline; clear wavy boundary.

Bt2--20 to 31 inches, brown (7.5YR 5/3) loam, brown (7.5YR 4/3) moist; moderate fine angular blocky; hard, very firm; violently effervescent; moderately alkaline; gradual smooth boundary.

C--31 to 71 inches, brown (7.5YR 5/3) clay loam, brown (7.5YR 4/3) moist; moderate very fine angular blocky; hard, very firm; 3 percent gravel; violently effervescent; slightly alkaline.

TYPE LOCATION: Coconino County, Arizona; Geographic Coordinate System 35 degrees 51 minutes 39.5 seconds north and 112 degrees 11 minutes and 47.2 seconds west

RANGE IN CHARACTERISTICS:
Soil moisture regime: ustic bordering on aridic
Mean annual soil temperature: 50 to 54 degrees F
Rock fragment content: 0 to 5 percent
Particle-size control section:
Clay content: 20 to 30 percent

A horizon
Hue: 7.5YR or 10YR
Value: 4 or 5 (3 or 4 moist)
Chroma: 2 or 3, dry or moist
Calcium carbonate equivalent: 2 to 10 percent
Reaction: slightly alkaline or moderately alkaline

B horizon
Hue: 7.5YR or 10YR
Value: 4 or 5 (3 or 4 moist)
Chroma: 2 or 3, dry or moist
Texture: loam or clay loam
Calcium carbonate equivalent: 2 to 15 percent
Sodium Adsorption Ratio (SAR): 0 to 2
Reaction: slightly alkaline or moderately alkaline

C horizon
Hue: 7.5YR or 10YR
Value: 4 or 5 (3 or 4 moist)
Chroma: 2 or 3, dry or moist
Texture: loam or clay loam
Calcium carbonate equivalent: 10 to 15 percent
Sodium Adsorption Ratio (SAR): 0 to 2
Reaction: slightly alkaline or moderately alkaline

COMPETING SERIES: There is no competing series.

GEOGRAPHIC SETTING:
Parent material: alluvium derived predominantly from limestone and dolomite
Landform: washes and stream terraces
Slopes: 0 to 3 percent
Elevation: 5,500 to 6,700 feet
Mean annual air temperature: 50 to 54 degrees F
Mean annual precipitation: 14 to 18 inches
Precipitation peaks in July and August, and in winter months. May and June are much drier.
Frost-free period: 135 to 165 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Maryrussell soils. Maryrussell soils have an argillic horizon, and are on terrace deposits generally higher in the stratigraphy than Cococo soils.

DRAINAGE AND PERMEABILITY: well drained, moderately rapid permeability

USE AND VEGETATION: These soils are used principally as grazing land and habitat. Native vegetation is mainly sagebrush, fourwing saltbush, algerita, blue grama, muttongrass, and broom snakeweed.

DISTRIBUTION AND EXTENT: Northern Arizona. MLRA 35.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.

SERIES ESTABLISHED: Coconino County, Arizona.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: from 0 to 2 inches. (A horizon)
Cambic horizon: from 10 to 31 inches. (Bt horizons).

Soil horizons do not have a sufficient accumulation of argillans to classify as argillic.
Name is derived from Coconino County
Taxonomic Version: Keys to Soil Taxonomy, Twelfth Edition, 2014
________________________________________

---

National Cooperative Soil Survey
U.S.A.