LOCATION COXWELL NMEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, thermic Ustic Haplargids
TYPICAL PEDON: Coxwell gravelly sandy loam (colors are for dry soil unless otherwise stated). The surface is covered with 50 percent pebbles and 10 percent cobblestones.
A--0 to 3 inches; brown (10YR 5/3) gravelly sandy loam, dark brown (10YR 3/3) moist; weak fine granular structure; slightly hard, very friable, nonsticky and nonplastic; many fine roots; many fine interstitial pores; 30 percent fine angular granitic gravel; neutral (pH 7.0); clear smooth boundary (2 to 7 inches thick).
Bt1--3 to 13 inches; reddish brown (5YR 5/4) gravelly clay loam, reddish brown (5YR 4/4) moist; weak medium prismatic structure parting to weak medium subangular blocky; hard, friable, moderately sticky and slightly plastic; common fine roots; many very fine interstitial pores; clay bridges between and coatings on sand grains, clay films in pores; 30 percent fine angular granitic gravel; neutral (pH 7.2); clear wavy boundary (4 to 12 inches thick).
Bt2--13 to 17 inches; reddish yellow (5YR 6/6) very gravelly clay loam, yellowish red (5YR 4/6) moist; weak medium subangular blocky structure; hard, friable, moderately sticky and slightly plastic; common fine roots; many very fine and fine interstitial pores; clay bridges between and coatings on sand grains, clay films in pores; 40 percent fine angular granitic gravel; neutral (pH 7.2); clear wavy boundary (4 to 10 inches thick).
Bt3--17 to 22 inches; reddish yellow (5YR 6/6) very gravelly sandy clay loam, yellowish red (5YR 5/6) moist; weak coarse subangular blocky structure; hard, friable, moderately sticky and slightly plastic; few fine roots; common fine interstitial pores; clay coatings on sand grains and clay films lining pores; 60 percent fine angular granitic gravel; neutral (pH 7.2); clear wavy boundary (5 to 13 inches thick).
Bt4--22 to 33 inches; reddish yellow (7.5YR 6/6) extremely gravelly sandy clay loam, strong brown (7.5YR 5/6) moist; weak coarse subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few fine roots; common pores; 80 percent fine angular granitic gravel; neutral (pH 7.2); clear wavy boundary (5 to 13 inches thick).
Cr--33 to 40 inches; granitic rock weathered to saprolite that parts to individual crystals about 1/4 inch in diameter.
TYPE LOCATION: Dona Ana County, New Mexico; on U. S. Highway 70, 1 mile east of the Observation Part on San Augustin Pass, in road cut on north side of highway; NW1/4 SE1/4 sec. 32, T.21S., R.4E.
RANGE IN CHARACTERISTICS:
Soil moisture: Ustic aridic moisture regime
Depth to weathered granite: 20 to 40 inches
Reaction: neutral or slightly alkaline
A horizon
Hue: 7.5YR, 10YR
Value: 5 or 6 dry, 3 or 4 moist
Chroma: 3 or 4, dry or moist
Texture: gravelly sandy loam, gravelly sandy clay loam.
Bt horizon
Hue: 2.5YR to 7.5YR
Value: 4 to 6 dry, 3 to 5 moist
Chroma: 4 to 6.
Texture: gravelly or very gravelly clay loam, or sandy clay loam
(What about the extremely gravelly layer at 22 to 33 inches)?
Effervescence: noncalcareous or slightly calcareous in the lower B horizon.
COMPETING SERIES: These are the Caralampi (AZ), Hartpeak (CA), Holliday (NM), Hoppswell (NV), Hyrhy (AZ), Maloy (AZ), and Monza (NM) series. The Caralampi, Holliday, Hoppswell, and Maloy soils are more than 60 inches deep. Monza soils have a shallow to very shallow argillic horizon overlying fractured paralithic Monzonite that extend to more than 20 inches. Hartpeak soils are moderately deep to a lithic contact.
GEOGRAPHIC SETTING: Coxwell soils formed in gravelly alluvial sediments over weathered granitic bedrock. Coxwell soils are on ridges along mountain toe slopes and have slopes of 5 to 15 percent. Elevations range from 4,800 to 6,000. The alluvial sediments are derived from weathered granite. The mean annual temperature is 59 degrees to 62 degrees F., and the mean annual precipitation is 9 to 12 inches. The frost-free season is 185 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aladdin and Sonoita soils. These soils are more than 60 inches deep and have less than 15 percent gravel in the 10 to 40 inch control section.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately slow permeability.
USE AND VEGETATION: Used mainly for rangeland and military purposes. Native vegetation is dominantly black grama, sideoats grama, Arizona cottontop, soap tree yucca and annuals.
DISTRIBUTION AND EXTENT: Southern New Mexico where it is inextensive. MLRA 42
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Dona Ana County, New Mexico, 1977.
REMARKS:
Diagnostic horizon and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 3 inches (A horizon)
Argillic horizon - the zone from 3 to 33 inches (Bt1, Bt2, Bt3, and Bt4) horizons)
Particle size control section - the zone from 3 to 23 inches (Bt1, Bt2 and Bt3 and 1 inch of the Bt4 horizons)
Paralithic- the contact from 33 to 40 inches (Cr horizon)
Updated competing series section 3/13/08, CEM