LOCATION XANKEY NMEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Typic Haplustalfs
TYPICAL PEDON: Xankey very cobbly loam, extremely stony -- on a planar backslope sloping 36 percent to the west at 7,860 feet elevation -- forest. Surface covered with discontinuous layer of needles, leaves, and twigs. (Colors are for dry soil unless otherwise noted. When described, the soil was moist from 6 to 30 inches and otherwise dry.)
A-- 0 to 6 inches; dark brown (7.5YR 3/2) very cobbly loam, black (7.5YR 2/1) moist; moderate thick platy structure parting to moderate medium granular; slightly hard, very friable, slightly sticky and nonplastic; common medium and fine and few very fine roots; common very fine irregularly shaped pores; 30 percent cobbles, 10 percent stones, 5 percent pebbles, and 2 percent boulders; neutral (pH 6.8); abrupt smooth boundary. (2 to 8 inches thick)
Bt1-- 6 to 14 inches; brown (7.5YR 4/4) very cobbly sandy clay loam, dark brown (7.5YR 3/4) moist; moderate fine subangular blocky structure; hard, firm, sticky and slightly plastic; common medium and few coarse and very fine roots; few very fine irregularly shaped and common fine tubular pores; common thin clay films on faces of peds and lining pores; 30 percent cobbles, 15 percent stones, and 5 percent pebbles; neutral (pH 6.8); clear smooth boundary. (5 to 12 inches thick)
Bt2-- 14 to 30 inches; brown (7.5YR 5/4) very stony sandy clay loam, brown (7.5YR 4/4) moist; moderate coarse subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common coarse and medium and few fine and very fine roots; common fine and very fine tubular pores; many thin clay films on faces of peds and lining pores; 25 percent stones, 20 percent cobbles, and 5 percent pebbles; neutral (pH 7.0); gradual smooth boundary. (7 to 20 inches thick)
2BC-- 30 to 37 inches; light brown (7.5YR 6/4) sandy loam, brown (7.5YR 4/4) moist; weak coarse subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; common very fine and few medium and fine roots; common very fine and few fine tubular pores; 5 percent pebbles and 5 percent cobbles; neutral (pH 7.0); clear smooth boundary. (5 to 13 inches thick)
2C1-- 37 to 44 inches; light gray (10YR 7/2) sandy loam, light brownish gray (10YR 6/2) moist; massive; soft, very friable, slightly sticky and nonplastic; common very fine and few medium and fine roots; common very fine tubular pores; 5 percent pebbles and 5 percent cobbles; neutral (pH 7.0); gradual smooth boundary. (7 to 20 inches thick)
2C2-- 44 to 63 inches; very pale brown (10YR 7/3) sandy loam, brown (10YR 5/3) moist; massive; soft, very friable, slightly sticky and nonplastic; common very fine and few fine roots; few very fine tubular pores; 5 percent pebbles and 5 percent cobbles; slightly alkaline (pH 7.8).
TYPE LOCATION: San Juan County, New Mexico; on the Navajo Indian Reservation about 8.5 miles west-northwest of Sanostee; 875 feet west and 1,825 feet north of the southeast corner of sec. 24, T.26N., R.21W.; Latitude 36 degrees 28 minutes 16 seconds N and Longitude 109 degrees 1 minute 36 seconds W.
RANGE IN CHARACTERISTICS:
Soil moisture - Typically, 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 moist in all parts less than 40 percent of the time (cumulative), when the soil temperature at 20 inches is 41 degrees F or higher. Typic ustic moisture regime.
Soil temperature - 44 to 47 degrees F.
Mean summer soil temperature - 61 to 65 degrees F.
Reaction - neutral to slightly alkaline
Silicate clay content, control section weighted average - 20 to 30 percent
Rock fragments content, control section weighted average - 35 to 60 percent
Depth to base of Argillic horizon - 24 to 40 inches
Depth to lithologic discontinuity of loamy material - 29 to
40 inches
A horizon
Hue: 5YR or 7.5YR.
Value: 3 or 4 dry, 2 or 3 moist.
Chroma: 2 or 3.
Organic carbon content: 0.6 to 1.2 percent.
Rock fragments: Total range is 35 to 60 percent; 5 to 10 percent pebbles; 25 to 30 percent cobbles; 5 to 15 percent stones; 0 to 5 percent boulders.
Bt horizons
Hue: 5YR or 7.5YR.
Value: 4 through 6 dry, 3 through 5 moist.
Chroma: 3 through 6.
Texture: very cobbly sandy clay loam or very stony sandy clay loam. Clay content: 20 to 30 percent.
Rock fragments: Total range is 35 to 60 percent; 0 to 5 percent pebbles; 20 to 30 percent cobbles; 15 to 25 percent stones.
2BC and 2C horizons
Hue: 5YR through 10YR.
Value: 5 through 7 dry, 4 through 6 moist.
Chroma: 2 through 6.
Texture: sandy loam or cobbly sandy loam.
Rock fragments: Total range is 10 to 25 percent; 5 to 15 percent pebbles; 5 to 10 percent cobbles.
COMPETING SERIES: These are the Colomex (NM), Laventana (NM), Macmeal (MT), Mocmont (MT), Namon (UT), Sheek (CO), Skyview (MT), Sonsela (NM), Tecolote (CO), Towaoc (CO), Trapps (MT), Vision (MT), Wahatoya (CO), Ymark (MT), Yourame (MT), and Yreka (MT) series. Ymark soils are deep. Macmeal, Trapps, and Yourame soils have accumulations of calcium carbonate. Colomex soils formed in stratified alluvium and have an abrupt change to sandy textures within 40 inches. Laventana soils have albic horizons. Mocmont soils have glossic horizons. Namon soils are deep to a lithic contact of sandstone. Sheek soils have moderately slow permeability. Skyview and Wahatoya soils are moderately deep. Sonsela soils are more moist and lack loamy substrata within 40 inches. Tecolote soils have an albic horizon. Towaoc soils have more than 18 percent clay. Vision soils formed in mixed igneous, metamorphic, and sedimentary parent material. Yreka soils have mixed E/Bt horizons. In addition, Macmeal, Mocmont, Skyview, Trapps, Vision, Wahatoya, Ymark, Yourame, and Yreka soils are moist in May and June.
GEOGRAPHIC SETTING: Xankey soils are on backslopes below mesas and stable landslides. They formed in colluvium derived from Tertiary sandstone and basalt. Slopes are 25 to 70 percent. Elevation ranges from 7,500 to 8,500 feet. The mean annual precipitation is 16 to 20 inches with more than 50 percent falling as snow from winter storms. The mean annual temperature is 42 to 45 degrees F. The average frost-free period is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kunz, Tuntsa, and Yahmore soils. Kunz soils are fine-loamy and occur on adjacent footslopes. Tuntsa soils are coarse-loamy, lack argillic horizons, and occur on non-wooded footslopes. Yahmore soils are coarse-loamy, have thick mollic epipedons, and occur on footslopes.
DRAINAGE AND PERMEABILITY: Well drained; rapid runoff; moderate permeability
USE AND VEGETATION: Xankey soils are used for timber production and livestock grazing. Present vegetation is ponderosa pine and Douglas fir with an understory of muttongrass, bottlebrush squirreltail, earth sedge, Gambel oak, Bailey yucca, Oregongrape, and pinyon.
DISTRIBUTION AND EXTENT: Xankey soils are of small extent on the Defiance Uplift-Chuska Mountains portion of the Colorado Plateau province in northwest New Mexico and northeast Arizona. MLRA 39.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: San Juan County, New Mexico, Shiprock Area Soil Survey, 1993. Xankey is a coined name.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to a depth of about 6 inches. (A horizon)
Argillic horizon - The zone from 6 to about 30 inches. (Bt1 and Bt2 horizons)
Major lithologic discontinuity - The change from skeletal to loamy material at about 30 inches (2BC, 2C1, and 2C2 horizons)
Classified according to Soil Taxonomy Second Edition, 1999; Keys to Soil Taxonomy Tenth Edition, 2006.
ADDITIONAL DATA: Organic carbon values are estimated.