LOCATION PASTERN UT+AZ

Established Series
Rev. DTH/MJD/VLP/WWJ/RKS/HCD
12/2022

PASTERN SERIES

The Pastern series consists of very shallow and shallow over hardpan, well drained, moderately permeable soils that formed in mixed alluvium and eolian material derived dominantly from sandstone, conglomerate and limestone. Pastern soils are on pediments, fan terraces and structural benches, and have slopes of 2 to 20 percent. The average annual precipitation is about 10 inches and the mean annual temperature is about 52 degrees F.
TAXONOMIC CLASS: Loamy, mixed, superactive, mesic, shallow Ustic Petrocalcids
TYPICAL PEDON: Pastern gravelly fine sandy loam--rangeland. (Colors are for air-dry soil unless otherwise stated)
A--0 to 1 inch; reddish brown (5YR 5/4) gravelly fine sandy loam, reddish brown (5YR 4/4) moist; moderate fine and very fine subangular blocky structure parting to moderate very fine granular; soft, very friable; common very fine and fine roots; many very fine interstitial pores; 35 percent gravel on the surface, and 8 percent angular gravel in the matrix; strongly calcareous, carbonates are disseminated; moderately alkaline (pH 8.2); abrupt smooth boundary. (0 to 2 inches thick)
Bw1--1 to 5 inches; yellowish red (5YR 5/6) fine sandy loam, yellowish red (5YR 4/6) moist; moderate coarse and very coarse prismatic structure parting to weak medium and coarse subangular blocky; slightly hard, very friable, slightly sticky; common very fine, fine, and few coarse roots; common very fine, fine and few coarse tubular pores; 5 percent angular gravel; strongly calcareous, carbonates are as coating on the underside of gravel; moderately alkaline (pH 8.2); clear wavy boundary. (3 to 5 inches thick).
Bw2--5 to 13 inches; yellowish red (5YR 5/6) fine sandy loam, yellowish red (5YR 4/6) moist; weak medium and coarse subangular blocky structure; slightly hard, very friable, slightly sticky; common very fine, fine, and few coarse roots; common very fine, fine, and few coarse tubular pores; 7 percent angular gravel; very strongly calcareous, carbonates are as coatings on undersides of gravel; moderately alkaline (pH 8.2); clear wavy boundary. (3 to 9 inches thick).
Bk--13 to 18 inches; pink (5YR 7/4) gravelly fine sandy loam, reddish yellow (5YR 6/6) moist; massive; slightly hard, very friable, slightly sticky; few very fine and coarse roots; common very fine, fine and few coarse tubular pores; 20 percent gravel including pockets up to 40 percent; very strongly calcareous, carbonates are disseminated and weakly cemented in places; moderately alkaline (pH 8.4); abrupt wavy boundary. (2 to 6 inches thick).
Bkm--18 inches; pinkish white (5YR 8/2) carbonate-cemented hardpan; roots matted on top of the hardpan.
TYPE LOCATION: Grand County, Utah - Central Part, about 1 1/2 miles south of Dubinky Well, about 1,000 feet east and l00 feet north of the southwest corner of sec. 36. T. 24 S., R. 18 E.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 52 to 57 degrees F.
Soil moisture: The soils are dry 50 to 75 percent of the time cumulative, when the soil temperature is greater than 4l degrees F. and are not moist for 90 consecutive days, when the soil temperature is greater than 47 degrees F. The moist period occurs during the 4 months following the summer solstice. Ustic aridic moisture regime.
Depth to petrocalcic horizon: 7 to 20 inches
Thickness of petrocalcic horizon: 6 to 36 inches
Depth to bedrock: greater than 60 inches
Rock fragments (particle-size control section): 5 to 35 percent
Clay content (particle-size control section): 5 to 18 percent
A horizon
Hue: 7.5YR, 5YR, or 2.5YR
Calcium carbonate: slightly calcareous or moderately calcareous
Bw horizon
Hue: 7.5YR, 5YR, or 2.5YR
Value: 5 or 6 dry, 4 moist
Chroma: 3 to 6
Texture: fine sandy loam, loam, but has thin lenses of gravelly fine sandy loam
Reaction: moderately alkaline or strongly alkaline
Calcium carbonate: moderately calcareous or strongly calcareous
Bk horizon
Value: 5 to 8 dry, 4 to 7 moist
Chroma: 3 to 6
Texture: gravelly fine sandy loam, or gravelly loam
Rock fragments: 15 to 35 percent gravel
Calcium carbonate: strongly calcareous or very strongly calcareous
COMPETING SERIES: These are Pastura (NM), Promontory (AZ), Rolie (AZ) and Tassi (AZ) series. Pastura, and Rolie soils have more than 20 percent clay in the particle-size control section. In addition, Pastura soils are moist in May and June. Promontory soils have rhyolite bedrock directly below the hardpan. Tassi soils have limestone bedrock directly below the hardpan.
GEOGRAPHIC SETTING: Pastern soils are on pediments, fan terraces and structural benches. Slope ranges from 2 to 20 percent. Elevations range from 4,300 to 5,600 feet. These soils formed in mixed alluvium, residuum and eolian material derived dominantly from sandstone, conglomerate and limestone. Mean annual air temperature is 49 to 55 degrees F. and the average annual precipitation is 8 to 14 inches. The precipitation is distributed evenly throughout the year with a slight bulge in July, August, September and October. The driest months are April, May and June. The freeze-free period is about 140 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are ThumbRock, Begay, Factory, Mido and Rizno soils. The ThumbRock soils are 20 to 40 inches deep to hard sandstone. The Begay soils are more than 60 inches deep. Factory soils have a petrocalcic horizon at a depth of 20 to 40 inches. The Mido soils are more than 60 inches deep and have sandy particle-size control sections. Rizno soils have bedrock at a depth of 4 to 20 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.
USE AND VEGETATION: Used mainly for livestock grazing. The potential vegetation is mainly blackbrush, blue grama, galleta and Mormon-tea.
DISTRIBUTION AND EXTENT: Southeastern Utah and Northern Arizona; MLRAs 34 and 35. The series is of moderate extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Henry Mountain Area, Utah, 1985.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface to 1 inch (A horizon).
Cambic horizon - the zone from 1 to 13 inches (Bw1, Bw2 horizon).
Petrocalcic horizon - the carbonate cemented hardpan at 18 inches (Bkm horizon).
Particle-size control section - the zone from 10 to 40 inches.
Classified according to Keys to Soil Taxonomy Ninth Edition, 2004.
Classification changed from Ustollic Paleorthid to Ustic Petrocalcids in 12/94.
Removed Esplin from competing series section because it changed to the Ustalfic Petrocalcids subgroup, tdc 08/2019
ADDITIONAL DATA: NSSL sample number S82UT-037-004.

National Cooperative Soil Survey
U.S.A.