LOCATION SANMOSS TXEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, thermic Pachic Haplustolls
TYPICAL PEDON: Sanmoss very gravelly loam - rangeland (colors are for dry soil unless otherwise noted).
A1--0 to 10 inches; reddish brown (5YR 5/3) very gravelly loam, dark reddish brown (5YR 3/3) moist; moderate fine subangular blocky structure; slightly hard, friable; many fine roots; 50 percent igneous gravel; neutral; clear smooth boundary.
A2--10 to 24 inches; reddish brown (5YR 5/3) very gravelly loam, dark reddish brown (5YR 3/3) moist; moderate fine subangular blocky structure; slightly hard, friable; many fine roots; 50 percent igneous gravel; noneffervescent; neutral; clear smooth boundary (combined thickness of A horizons 20 to 30 inches).
Bk--24 to 60 inches; brown (7.5YR 5/4) extremely gravelly loam, dark brown (7.5YR 3/4) moist; weak fine subangular blocky structure; slightly hard, friable; few fine roots; 80 percent igneous gravel; few masses of calcium carbonate; violently effervescent; moderately alkaline; clear smooth boundary (10 to 40 inches thick).
C--60 to 80 inches; brown (7.5YR 5/4) very gravelly loam, dark brown (7.5YR 3/4) moist; massive; few fine roots; 35 percent igneous gravel; few carbonate filaments; violently effervescent; moderately alkaline.
TYPE LOCATION: Jeff Davis County, Texas. From the Jeff Davis-Culberson county line on Texas Highway 118, 7.5 miles south on Texas Highway 118, and 100 feet west in range. Echo Canyon USGS topographic quadrangle; Latitude 30 degrees, 57 minutes, 6.2 seconds North; Longitude 104 degrees, 9 minutes, 43.1 seconds West; 580,046 m Easting; 3,424,552 m Northing; UTM zone 13; NAD 83 datum.
RANGE IN CHARACTERISTICS:
Soil moisture: Intermittently moist in some part of the soil moisture control section during July-September. Aridic ustic moisture regime.
Mean annual soil temperature: 58 to 64 degrees
Mean annual precipitation: 14 to 18 inches
Thickness of mollic epipedon: 20 to 30 inches
Particle size control section (weighted average)
Clay content: 18 to 35 percent
Igneous rock fragment content: 35 to 80 percent gravel, 0 to 25 percent cobbles, and 0 to 10 percent stones
Organic matter content: greater than 1.0 percent in the upper 20 inches; decreasing regularly with depth
Reaction: neutral to moderately alkaline
Depth to secondary lime accumulation: 12 to 40 inches.]
A horizon
Hue: 5YR, 7.5YR, 10YR
Value: 3 to 5 dry, 1 to 3 moist
Chroma: 1 to 3, dry or moist
Clay content: 18 to 35 percent
Rock fragment content: 25 to 50 percent igneous gravel
Reaction: neutral to moderately alkaline
Calcium carbonate equivalent: 0 to 5 percent
Bk horizons
Hue: 5YR, 7.5YR, 10YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 4 or 5, dry or moist
Clay content: 18 to 35 percent
Rock fragment content: 35 to 50 percent igneous gravel, cobbles, and stones
Reaction: Slightly alkaline to moderately alkaline
Calcium carbonate equivalent: 2 to 5 percent
C horizon
Hue: 5YR, 10YR
Value: 4 or 5, dry or moist
Chroma: 4 or 5, dry or moist
Clay content: 18 to 35 percent
Rock fragment content: 35 to 50 percent igneous gravel, cobbles, and stones
Reaction: Slightly alkaline to moderately alkaline
Calcium carbonate equivalent: 2 to 5 percent
COMPETING SERIES: These are the
Enash (NM) and
Santo Tomas (NM) series.
Santo Tomas soils are in the ustic aridic moisture regime and Enash and Santo Tomas soils have mollic epipedon that are more than 30 inches thick. Enash and Santo Tomas soils are noncalcareous in all sub horizons.
GEOGRAPHIC SETTING:
Parent material: gravelly and very gravelly alluvium derived from siliceous igneous rocks
Landform: alluvial fans and terraces of late-Pleistocene age
Mean Annual Precipitation: 14 to 18 inches
Precipitation pattern: Precipitation falls mostly during the months of July through September. The driest months are March and April. Additional run-on moisture is received from adjacent mountains
Slope gradients: 1 to 15 percent; usually 5 to 10 percent
Mean annual air temperature: 59 to 64 degrees
Elevation: 4500 to 6500 feet
Frost-free period: 160 to 200 days
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Brewster, Boracho, Espy, Mainstay, and Medley series. Medley soils occur in complex map units with Sanmoss soils. Medley soils occur along drainageways and low terraces, whereas Sanmoss soils are situated on alluvial fans adjacent to the bedrock uplands. Brewster, Boracho, Espy, Mainstay soils occur within other, adjacent map units. Brewster and Mainstay soils are on rolling to very steep hills and mountains, and are shallow to igneous bedrock. Mainstay soils have argillic horizons. Boracho and Espy soils are on Pleistocene age, caliche cemented alluvial fans and piedmont slopes. They are shallow to petrocalcic horizons. Espy soils are non-skeletal.
DRAINAGE AND PERMEABILITY: Well-drained; medium runoff; moderate permeability.
USE AND VEGETATION: Used for livestock grazing and wildlife habitat. Vegetation is a mid- and short-grass prairie with scattered woody plants. Grasses include sideoats grama, cane bluestem, blue grama, hall's panicum, black grama, sand muhly, threeawn species, and hairy grama. Woody species include roseberry juniper, cholla, algerita, butterflybush, prickly pear, and oak species.
DISTRIBUTION AND EXTENT: Davis Mountains of Trans-Pecos Texas; LRR D, MLRA 42, Southern Desertic Basins, Plains, and Mountains; Mixed Prairie Ecological Zone. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Brewster County, Texas, Main Part, 2001
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: the zone from 0 to 24 inches (A1 and A2 horizons)
Pachic feature: the over-thickened mollic epipedon with regular decreasing organic matter
Cambic horizon: the zone from 24 to 60 inches (Bk horizon)
Classified according to Soil Taxonomy, Second Edition, 1999.
Update competing series section 4/11/08, CEM