LOCATION HOXOH NMTentative Series
TAXONOMIC CLASS: Ashy-skeletal, glassy, frigid Lithic Haplustolls
TYPICAL PEDON: Hoxoh gravelly ashy loam--on a summit of an undulating plateau sloping 6 percent to the east-northeast at 8,355 feet elevation--forestland. (Colors are for dry soil unless otherwise noted. When described on September 1, 2000, the soil was slightly moist from 6 to 17 inches and otherwise dry.)
Oi--0 to 2 inches; slightly decomposed needles, twigs, and cones; clear smooth boundary. (1 to 3 inches thick)
A--2 to 7 inches; dark grayish brown (10YR 4/2) gravelly ashy loam, very dark brown (10YR 2/2) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; few coarse, few medium, few fine, and few very fine roots; common very fine irregularly shaped pores; 15 percent gravel and 5 percent cobbles; neutral (pH 7.2); gradual wavy boundary. (5 to 7 inches thick)
Bw--7 to 17 inches; brown (10YR 5/3) very gravelly ashy loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; few medium and few fine roots; few fine tubular pores; 40 percent gravel, 10 percent cobbles, and 5 percent stones; slightly alkaline (pH 7.4); abrupt wavy boundary. (7 to 12 inches thick)
R--17 inches; strongly cemented rhyolitic tuff bedrock.
TYPE LOCATION: Bandelier National Monument, Los Alamos County, New Mexico; USGS Bland 7.5 minute topographic quadrangle; about 5 miles southwest of Los Alamos; Latitude 35 degrees 49 minutes 42.80 seconds North and Longitude 106 degrees 22 minutes 56.79 seconds West, NAD 27.
RANGE IN CHARACTERISTICS: (Depths given are measured from the mineral soil surface)
Soil moisture - The soil moisture control section (SMCS) is moist in all parts from January to May and intermittently moist in some part from June to December. The SMCS is dry in all parts less than 40 percent of the time when the soil temperature at 20 inches is above 41 degrees F. The soil moisture regime is typic ustic.
Average annual soil temperature: 45 to 47 degrees F
Thickness of mollic epipedon: 10 to 20 inches
Organic matter content: 2 to 4 percent in mollic epipedon
Depth to lithic contact: 10 to 20 inches
Lithology of rock fragments: Rhyolitic tuff
Oxalate extractble Al + 1/2Fe: .01 to .10 percent
Particle-size control section:
Rock fragment content: total range is 35 to 60 percent
Volcanic glass content: 50 to 70 percent in the coarse silt plus sand fraction
A horizon
Value: 3 or 4 dry, 2 or 3 moist
Chroma: 2 or 3, dry or moist
Clay content: 8 to 18 percent
Rock fragments: total range is 15 to 35 percent
15 to 25 percent gravel
0 to 10 percent cobbles
Bw horizons
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 2 or 3, dry or moist
Texture: very gravelly ashy loam or very gravelly ashy sandy loam
Clay content: 8 to 18 percent
Sand content: 40 to 60 percent
Fine sand or coarser content: 30 to 50 percent
Rock fragments: total range is 35 to 60 percent
25 to 45 percent gravel
5 to 15 percent cobbles
0 to 5 percent stones
COMPETING SERIES: There are no competing series. A similar soil in another family is the Cymery series. Cymery soils do not have mollic epipedons.
GEOGRAPHIC SETTING: Hoxoh soils are on summits and shoulders of interfluves on undulating plateaus. They formed in slope alluvium and residuum derived locally from Quaternary Age rhyolitic tuff. Slopes are 1 to 15 percent. Elevation ranges from 7,600 to 8,600 feet. The mean annual precipitation is 20 to 24 inches with about 45 percent falling as rain from high-intensity convective thunderstorms between July and September. The mean annual air temperature is 43 to 45 degrees F. The frost-free period is 110 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cajete, Cymery, Jemez, and Tschicoma soils. Cajete soils are ashy-pumiceous, are very deep, and occur on north-facing backslopes of undulating plateaus. Cymery soils are ashy-skeletal, do not have mollic epipedons, and are on summits and shoulders of undulating plateaus. Jemez soils are fine-loamy, have argillic horizons, and are on summits and shoulders of interfluves. Tschicoma soils are fine-loamy, have argillic horizons, and occur on footslopes and toeslopes of interfluves.
DRAINAGE AND PERMEABILITY: Well drained; medium surface runoff; permeability is moderately rapid.
USE AND VEGETATION: Hoxoh soils are used for recreation and wildlife habitat. Present vegetation includes ponderosa pine, Douglas fir, New Mexico locust, Gambel oak, quaking aspen, nodding brome, and mountain muhly
DISTRIBUTION AND EXTENT: Hoxoh soils are of small extent on the southwestern Jemez Volcanic Field part of the Southern Rocky Mountain province in northcentral New Mexico. The MLRA is 48A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Los Alamos County, New Mexico; Bandelier National Monument Soil Survey, 2000. Hoxoh is a coined name.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from 2 to 17 inches. (A and Bw horizons)
Lithic contact -Strongly cemented rhyolitic tuff bedrock at 17 inches. (2R layer)
Particle-size control section - The zone from 12 to 17 inches (part of the Bw horizon)
Classified according to Soil Taxonomy Second Edition, 1999.