LOCATION OUTPOST AZ+NMEstablished Series
TAXONOMIC CLASS: Clayey over loamy, mixed, active, calcareous, mesic Vertic Torrifluvents
TYPICAL PEDON: Outpost sandy clay loam -- on a nearly level floodplain sloping 1 percent to the northeast at 5,235 feet elevation -- rangeland. (Colors are for dry soil unless otherwise noted. When described, the soil was moist from 4 to 23 inches and otherwise dry throughout.)
A--0 to 3 inches; pale brown (10YR 6/3) and reddish yellow (5YR 6/6) sandy clay loam, brown (10YR 4/3) and yellowish red (5YR 4/6) moist; moderate very thick platy structure parting to weak coarse granular; soft, very friable, sticky and slightly plastic; few fine and very fine roots; few fine and very fine irregularly shaped pores; few laminae and thin lenses of silt loam; few thin cracks 2 to 5 mm wide; strongly effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (2 or 3 inches thick)
Cy1--3 to 11 inches; pale brown (10YR 6/3) and reddish yellow (5YR 6/6) clay loam; brown (10YR 4/3) and yellowish red (5YR 4/6) moist; weak coarse subangular blocky structure; slightly hard, friable, sticky and plastic; common very fine roots; few fine tubular pores; few laminae and thin lenses of silt loam; few thin cracks 2 to 5 mm wide; secondary very fine sand sized gypsum segregated in very few fine irregularly shaped accumulations as filaments; strongly effervescent; strongly alkaline (pH 8.6); gradual smooth boundary. (3 to 13 inches thick)
Cy2--11 to 19 inches; pale brown (10YR 6/3) and reddish yellow (7.5YR 6/6) silty clay, brown (10YR 4/3) and strong brown (7.5YR 4/6) moist; weak coarse subangular blocky structure; very hard, firm, very sticky and very plastic; common very fine roots; few very fine tubular pores; few laminae of silt loam and very fine sandy loam; common pressure faces (stress cutans); few thin cracks 5 to 10 mm wide; secondary very fine sand sized gypsum segregated in very few fine irregularly shaped accumulations as filaments; strongly effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (3 to 17 inches thick)
Cssy1--19 to 27 inches; pale brown (10YR 6/3) and light brown (7.5YR 6/4) silty clay, brown (10YR 4/3) and brown (7.5YR 4/4); moderate medium subangular blocky structure; very hard, firm, very sticky and very plastic; common very fine roots; few fine and very fine tubular pores; few thin lenses of silt loam; few intersecting slickensides; few thin cracks 5 to 10 mm wide; secondary very fine sand sized gypsum segregated in few fine irregularly shaped accumulations as filaments; strongly effervescent; moderately alkaline (pH 8.4); gradual wavy boundary. (0 to 8 inches thick)
Cssy2--27 to 35 inches; light brownish gray (10YR 6/2) and light brown (7.5YR 6/4) silty clay, dark grayish brown (10YR 4/2) and brown (7.5YR 4/4); moderate medium subangular blocky structure; very hard, firm, very sticky and very plastic; few very fine roots; few very fine tubular pores; few thin lenses of silt loam; few intersecting slickensides; very few thin cracks 2 to 5 mm wide; secondary very fine sand sized gypsum segregated in common fine irregularly shaped accumulations as filaments; strongly effervescent; moderately alkaline (pH 8.0); abrupt wavy boundary. (0 to 10 inches thick)
Cy1'--35 to 49 inches; pale brown (10YR 6/3) and light brown (7.5YR 6/4) sandy loam, brown (10YR 4/3) and brown (7.5YR 4/4) moist; weak coarse subangular blocky structure; soft, very friable, slightly sticky and nonplastic; few very fine roots; few fine and very fine tubular pores; few strata of fine sandy loam; secondary very fine sand sized gypsum segregated in very few fine irregularly shaped accumulations as filaments; strongly effervescent; slightly alkaline (pH 7.4); clear smooth boundary. (5 to 30 inches thick)
Cy2'--49 to 58 inches; pale brown (10YR 6/3) stratified fine sandy loam, brown (10YR 5/3) moist; massive; slightly hard, very friable, slightly sticky and nonplastic; few very fine roots; few very fine tubular pores; few strata of sandy loam and few laminae of silt loam; secondary very fine sand sized gypsum segregated in very few fine irregularly shaped accumulations as filaments; strongly effervescent; slightly alkaline (pH 7.6); clear smooth boundary. (0 to 27 inches thick)
Cy3'--58 to 80 inches; pale brown (10YR 6/3) stratified loamy sand, brown (10YR 5/3) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine roots; few strata of fine sandy loam and few laminae of silty clay loam; secondary very fine sand sized gypsum segregated in few fine irregularly shaped accumulations as filaments in silty strata; strongly effervescent; slightly alkaline (pH 7.4).
TYPE LOCATION: Apache County, Arizona; on the Navajo Indian Reservation about 7.5 miles south-southwest of Rock Point; 1,850 feet east and 1,200 feet south of the northwest corner of section 18, T.37 N., R.25 E.; Latitude 36 degrees 27 minutes 6 seconds North and Longitude 109 degrees 41 minutes 30 seconds West.
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 56 degrees F.
Clay content - control section weighted average is 35 to 60 percent in the upper part and 8 to 15 percent in the lower part
Reaction - moderately to strongly alkaline in upper part and slightly to moderately alkaline in lower part
Cracking- few to common, 2 to 15 mm wide; averaging more than 5 mm wide through a thickness greater than 30 cm
Slickensides- few small intersecting surfaces are present in C horizons above the major lithologic discontinuity in layer(s) more than 15 cm thick.
AC horizon
Hue: 5YR through 10YR
Value: 5 or 6 dry, 3 through 5 moist
Chroma: 3 through 6, dry or moist
Salinity, mmhos/cm: 0 to 2
C and Css horizons
Hue: 5YR through 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 through 6, dry or moist
Texture: clay loam, silty clay loam, silty clay
Clay content: 35 to 60 percent
Salinity, mmhos/cm: 2 to 8
Gypsum content: 1 to 5 percent
Upper C' horizons
Hue: 5YR through 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 through 6, dry or moist
Texture: stratified sandy loam to silt loam
Clay content: 8 to 15 percent
Salinity, mmmhos/cm: 4 to 8
Gypsum content: 0 to 1 percent
Lower C and C' horizons
Hue: 5YR through 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 through 6, dry or moist
Texture: stratified loamy sand to silty clay loam
Clay content: 15 to 25 percent
Salinity: 4 to 8 dS/m
Gypsum content: 0 to 1 percent
COMPETING SERIES: There are no competitors.
GEOGRAPHIC SETTING: Outpost soils are on floodplains. They formed in alluvium derived from sandstone and shale. Slopes are 0 to 2 percent. Elevation ranges from 5,000 to 6,000 feet. The mean annual precipitation is 6 to 8 inches with 35 to 60 percent falling as rain or run-on moisture following prolonged, high-intensity, convective thunderstorms between July and September. The mean annual air temperature is 52 to 54 degrees F. The frost-free period is 140 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aneth, Mack, Redlands, and Sogzie soils. Aneth soils are sandy, contain buried loamy horizons, and occur on adjacent eolian-mantled surfaces. Mack soils are fine-loamy, have argillic and calcic horizons, and occur on high stream terraces. Redlands soils are fine-loamy, have argillic horizons, and occur on fan terraces. Sogzie soils are coarse-loamy, have argillic and calcic horizons, and occur on mesas and undulating plateaus.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; slow permeability in the upper part and moderate permeability in the lower part. These soils are subject to occasional, very brief periods of flooding between July and September.
USE AND VEGETATION: Used for livestock grazing. Present vegetation is alkali sacaton, galleta, fourwing saltbush, black greasewood, and Russian thistle.
DISTRIBUTION AND EXTENT: Outpost soils are of small extent on the Blanding Basin and Tyende Saddle portions of the Colorado Plateau province in northeast Arizona. 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 3 inches (A horizon)
Entisol feature - The lack of a diagnostic epipedon or diagnostic subsurface horizons
Major lithologic discontinuity - The abrupt change to loamy material at about 35 inches (2C1, 2C2, and 2C3 horizons)
A strongly contrasting particle-size class within a depth of 40 inches
Vertic properties - The presence of cracks wider than 5 mm and slickensides in a layer more than 30 cm thick which is within 125 cm of the soil surface (C2, Cyss1, Cyss2 horizons)
Keys to Soil Taxonomy - Soils classified according to the Eighth Edition, 1998.
ADDITIONAL DATA: Salinity values determined with an Instant EC salinity kit. Sodicity values determined for three horizons by Inter-Mountain Laboratories, Inc.