LOCATION SANDARK NM+AZEstablished Series
TAXONOMIC CLASS: Sandy, mixed, frigid Entic Haplustolls
TYPICAL PEDON: Sandark loamy fine sand -- on a fan terrace sloping 7 percent to the northeast at 7,965 feet elevation -- forest. (Colors are for dry soil unless otherwise noted.) The surface is covered with 2 inches of slightly decomposed pine needles and other forest litter.
A--0 to 5 inches; dark grayish brown (10YR 4/2) loamy fine sand, very dark brown (10YR 2/2) moist; moderate medium subangular blocky structure parting to weak medium granular; soft, very friable, slightly sticky and nonplastic; common medium and very fine roots; few fine and very fine tubular pores; slightly acid; clear smooth boundary. (4 to 12 inches thick)
Bw1--5 to 16 inches; brown (7.5YR 4/3) loamy fine sand, dark brown (7.5YR 3/3) moist; moderate coarse subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine and common medium roots; few very fine and fine tubular pores; neutral; clear wavy boundary. (6 to 20 inches thick)
Bw2--16 to 27 inches; brown (7.5YR 4/2) loamy fine sand, dark brown (7.5YR 3/2) moist; moderate coarse subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine and common medium roots; few very fine and fine tubular pores; neutral; clear smooth boundary. (6 to 20 inches thick)
Bw3--27 to 36 inches; brown (7.5YR 4/3) fine sand, dark brown (7.5YR 3/3) moist; moderate medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine and medium roots; few very fine tubular pores; neutral; clear smooth boundary. (0 to 12 inches thick)
E and Bt--36 to 66 inches; brown (10YR 5/3) fine sand (E part), brown (10YR 4/3) moist, with brown (7.5YR 5/4) loamy fine sand lamellae (Bt part), brown (7.5YR 4/4) moist; massive; slightly hard, very friable, nonsticky and nonplastic; few medium and very fine roots; few very fine tubular pores; clay coatings on sand grains in few thin discontinuous lamellae less than 0.5 inches thick; neutral.
TYPE LOCATION: San Juan County, New Mexico; on the Navajo Indian Reservation about 2.5 miles west-northwest of Toadlena; 100 feet west and 1,500 feet south of the northeast corner of sec. 11, T.23N., R.20W.; Latitude 36 degrees 14 minutes 44 seconds N and Longitude 108 degrees 56 minutes 6 seconds W.
RANGE IN CHARACTERISTICS:
Soil moisture - Typically the soil moisture control section is moist in all parts from January to May and intermittently moist in some part from June to December. Typic ustic moisture regime.
Soil temperature - 41 to 45 degrees F.
Depth to base of mollic epipedon - 14 to 40 inches
Silicate clay content, control section weighted average - 2 to 8 percent
Rock fragments - less than 10 percent
Reaction - slightly acid to neutral
Organic matter - 1 to 3 percent in the epipedon
A horizon - Hue: 7.5YR or 10YR
Value: 2 through 5 dry, 2 or 3 moist
Chroma: 1 through 3
Texture: loamy fine sand or loamy sand
Bw horizon - Hue: 7.5YR or 10YR
Value: 2 through 5 dry, 2 through 4 moist
Chroma: 2 or 3
Texture: loamy sand, fine sand, or loamy fine sand
E and Bt horizon - Hue: 7.5YR or 10YR
Value: 4 through 8 dry, 3 through 6 moist
Chroma: 2 through 6
Texture: loamy fine sand, loamy sand, or fine sand
Lamellae: sum of thickness is less than 6 inches within 2 m
COMPETING SERIES: These are the Lihen (MT), Schaller (ND), and Telfer (ND) series. These soils are moist in May and June.
GEOGRAPHIC SETTING: Sandark soils are on fan terraces and toeslopes. Sandark soils formed in alluvium derived from Tertiary sandstone. Slopes are 1 to 15 percent. Elevations range from 7,400 to 9000 feet. The mean annual precipitation is 18 to 24 inches. The mean annual air temperature is 39 to 43 degrees F. The frost-free period is 60 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Deza, Klizhin and Yahmore soils. The Deza soil does not have a mollic epipedon. The Klizhin and Yahmore soils have coarse-loamy control sections.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; slow or medium runoff; rapid permeability.
USE AND VEGETATION: Sandark soils are used for timber production and livestock grazing. Present vegetation is ponderosa pine, and Douglas fir, with an understory of Gamble oak, western brackenfern, Oregongrape, snowberry, mountain muhly, mountain brome, and silvery lupine.
DISTRIBUTION AND EXTENT: Sandark 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: Shiprock Area, Parts of San Juan County, New Mexico and Apache County, Arizona; 1993.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to a depth of about 36 inches (A, Bw1, Bw2, and Bw3 horizons)
Keys to Soil Taxonomy - Soils classified according to the Eighth Edition, 1998.