LOCATION SHUMBEGAY AZ+NMEstablished Series
TAXONOMIC CLASS: Sandy, mixed, mesic Typic Torriorthents
TYPICAL PEDON: Shumbegay loamy fine sand -- on a hummocky low stream terrace sloping 1 percent to the west at 4,950 feet elevation -- rangeland. (Colors are for dry soil unless otherwise noted. When described, the soil was moist from 1 to 5 inches.)
A--0 to 2 inches; light reddish brown (5YR 6/4) loamy fine sand, reddish brown (5YR 4/4) moist; moderate thick platy structure parting to weak medium granular; soft, very friable, nonsticky and nonplastic; few fine and very fine roots; few very fine vesicular pores; soil surface has a thin black cryptogam crust; strongly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (1 to 3 inches thick)
Btn--2 to 6 inches; red (2.5YR 5/6) loamy fine sand, red (2.5YR 4/6) moist; weak medium prismatic structure parting to moderate coarse subangular blocky; hard, friable, slightly sticky and nonplastic; few fine and common very fine roots; common very fine tubular pores; very few faint clay films on faces of peds and common faint clay bridging of sand grains; strongly effervescent; strongly alkaline (pH 9.0); clear smooth boundary. (3 to 5 inches thick)
BCn--6 to 10 inches; reddish yellow (5YR 6/6) loamy fine sand, yellowish red (5YR 5/6) moist; weak coarse subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; few coarse and fine and common very fine roots; few fine and very fine tubular pores; slightly effervescent; strongly alkaline (pH 9.0); clear wavy boundary. (0 to 11 inches thick)
Cn1--10 to 37 inches; reddish yellow (5YR 6/6) fine sand, yellowish red (5YR 4/6) moist; massive; soft, very friable, nonsticky and nonplastic; few fine and common very fine roots; few very fine tubular pores; few 1-2 cm lenses of very fine sandy loam; slightly effervescent; strongly alkaline (pH 8.8); gradual smooth boundary. (16 to 27 inches thick)
Cn2--37 to 80 inches; reddish yellow (5YR 6/6) loamy fine sand, yellowish red (5YR 4/6) moist; massive; soft, very friable, nonsticky and nonplastic; few fine and very fine roots; few very fine tubular pores; few 1-2 cm lamina of silt loam; slightly effervescent; strongly alkaline (pH 8.6).
TYPE LOCATION: Apache County, Arizona; on the Navajo Indian Reservation about .75 mile south of the Mexican Water Trading Post; 3,350 feet south and 2,150 feet east of the northwest corner of section 31, T.41 N., R.26 E.; Latitude 36 degrees 54 minutes 51 seconds N and Longitude 109 degrees 35 minutes 59 seconds W.
RANGE IN CHARACTERISTICS:
Soil moisture - The soil moisture control section is intermittently moist in some part from July to October and December to mid-April. Driest during May and June. Typic aridic soil moisture regime.
Soil temperature - 54 to 58 degrees F.
Clay content - less than 8 percent
Calcium carbonate equivalent - 1 to 3 percent
Organic carbon content - less than 0.29 percent
Salinity, dS/m - less than 2
Reaction - slightly to strongly alkaline in the surface and strongly alkaline in the B and C horizons
A horizon
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 4 through 6, dry or moist
Btn horizon
Hue: 2.5YR, 5YR
SAR: 13 to 30
BCn horizon
Value: 4 or 5 moist
Chroma: 6 through 8, dry or moist
SAR: 5 to 30
Texture: fine sand, loamy fine sand
Cn horizons
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 4 through 6, dry or moist
SAR: 5 to 30
Texture: loamy fine sand, fine sand; with lenses and thin strata of very fine sandy loam, fine sandy loam, silt loam
COMPETING SERIES: These are the Aneth (UT), Luning (NV), Soda Lake (NV), Soolake (NV), and Yerington (NV) series. Aneth soils have SAR of less than 13. Soda Lake soils have a Bw horizon, lime accumulations below 18 inches and contain few to 20 percent durinodes below 24 inches. Luning soils are moist 10 to 20 days cumulative between July and October due to convection storms. Soolake soils have a soil temperature that ranges form 48 to 53 degrees F., and do not have secondary lime accumulations at 12 to 24 inches. Yerington soils have a Bk horizon and do not have thin Btn horizons.
GEOGRAPHIC SETTING: Shumbegay soils are on hummocks and stable dunes of low stream terraces and structural benches. They formed in eolian material and alluvium derived from Triassic and Jurassic sandstone and siltstone. Slopes are 0 to 25 percent. Elevation ranges from 4,700 to 5,800 feet. The mean annual precipitation is 5 to 8 inches, with 35 to 60 percent falling as rain from high-intensity thunderstorms between July and September. The mean annual air temperature is 52 to 56 degrees F. The frost-free period is 140 to 170 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aneth and Tyende soils on structural benches, and the Gotho and Uzona soils on low stream terraces. Aneth soils occur on eolian-mantled summits of benches. Tyende soils occur on adjacent summits of benches as areas below stable dunes. Gotho soils are fine-loamy and occur on low stream terrace surfaces that have less accumulation of eolian material. Uzona soils are fine textured and occur in broad areas on low stream terraces.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; medium runoff; moderately rapid permeability due to high sodium content and thin strata of loamy textures.
USE AND VEGETATION: Shumbegay soils are used for livestock grazing. Present vegetation is black greasewood, alkali sacaton, Torrey seepweed, sand dropseed, and Indian ricegrass.
DISTRIBUTION AND EXTENT: Shumbegay soils are of small extent on the Tyende Saddle (Chinle and Walker Creek Valley areas) and Red Rock Bench (Red Wash area) portions of the Colorado Plateau province in northeast Arizona and northwest New Mexico. MLRA 35.
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:
Ochric epipedon - The zone from 0 to 2 inches (A horizon)
Entisol feature - The absence of diagnostic subsurface horizons. The Btn horizon does not qualify as a Natric horizon, because it is less than 6 inches (15 cm) thick.
Keys to Soil Taxonomy - Soils classified according to the Eighth Edition, 1998.
ADDITIONAL DATA: Organic carbon and calcium carbonate values are estimated. Salinity values were determined with an Instant EC salinity kit. The series type location was sampled for determination of particle-size and SAR, and the samples analyzed at a local soils laboratory in Farmington, New Mexico. A sample of black greasewood leaves taken at one sample site averaged 7 percent sodium on a dry weight basis. Release of this accumulated sodium may provide a possible source of sodium for pedogenesis.
Updated competing series section.