LOCATION PEATROSS UT

Tentative Series
SAC/SJJ/SAC
11/2018

PEATROSS SERIES

The Peatross series consists of very deep, somewhat poorly drained soils that formed in alluvium derived from sedimentary rocks. Peatross soils occur on stream terraces or floodplain-steps. Slopes range from 0 to 4 percent. Mean annual precipitation is about 360 mm(14 in) and the mean annual temperature is about 6.5 degrees C(43 F).

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Oxyaquic Haplustolls

TYPICAL PEDON: Peatross loam, 1 percent slope on cropland at an elevation of 1,870 meters. (Colors are for dry soil unless otherwise noted.)

Ap--0 to 18 cm; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; strong fine and medium subangular blocky structure; moderately hard, friable, slightly sticky and slightly plastic; many very fine, fine, and common medium roots; strongly effervescent; moderately alkaline, pH 7.9; abrupt smooth boundary. (15 to 26 cm thick)

C1--18 to 23 cm; brown (7.5YR 5/4) loamy sand, brown (7.5YR 4/4) moist; single grain; loose, loose, nonsticky and nonplastic; many very fine, fine, and common medium roots; common fine strong brown (7.5YR 5/6) moist, iron masses; violently effervescent; moderately alkaline, pH 7.9; abrupt smooth boundary. (0 to 15 cm thick)

Bwb1--23 to 35 cm; brown (7.5YR 5/4) loam, brown (7.5YR 4/3) moist; moderate medium subangular blocky structure; moderately hard, friable, slightly sticky and slightly plastic; common very fine, fine, and medium roots; common fine distinct red (2.5YR 4/6) moist, iron masses; strongly effervescent; moderately alkaline, pH 8.0; clear smooth boundary.

Ab--35 to 46 cm; dark brown (7.5YR 3/3) clay loam, very dark brown (7.5YR 2.5/2) moist; weak medium subangular blocky structure; moderately hard, friable, moderately sticky and moderately plastic; common very fine, fine, and medium roots; few fine distinct yellowish red (5YR 4/6) moist, iron masses; strongly effervescent; moderately alkaline, pH 7.9; clear smooth boundary. (0 to 15 cm thick)

Bwb2--46 to 56 cm; brown (7.5YR 4/4) clay loam, dark brown (7.5YR 3/4) moist; weak medium subangular blocky structure; moderately hard, friable, moderately sticky and moderately plastic; common very fine, fine, and medium roots; common fine distinct strong brown (7.5YR 4/6) moist, iron masses; strongly effervescent; moderately alkaline, pH 8.0; clear smooth boundary.

Bwb3--56 to 83 cm; brown (7.5YR 5/4) sandy clay loam, brown (7.5YR 4/4) moist; weak medium subangular blocky structure; moderately hard, friable, slightly sticky and slightly plastic; common very fine, fine, and medium roots; common fine distinct strong brown (7.5YR 4/6) moist, iron masses; strongly effervescent; moderately alkaline, pH 8.2; clear smooth boundary. (Combined thickness of the Bw horizons is 19 to 55 cm)

C2--83 to 118 cm; brown (7.5YR 5/4) sandy loam, brown (7.5YR 4/4) moist; massive; moderately hard, friable, slightly sticky and nonplastic; common very fine, fine, and medium roots; few fine distinct yellowish red (5YR 4/6) moist, iron masses; strongly effervescent; moderately alkaline, pH 8.0; clear smooth boundary.

C3--118 to 152 cm; 70 percent brown (7.5YR 5/4) and 30 percent pink (7.5YR 7/4) sandy loam, 70 percent brown (7.5YR 5/4) and 30 percent light brown (7.5YR 6/4) moist; massive; loose, very friable, slightly sticky and nonplastic; common very fine, fine, and medium roots; common fine distinct yellowish red (5YR 4/6) moist, iron masses; violently effervescent; moderately alkaline, pH 8.0.

TYPE LOCATION: Duchesne County, Utah; about 13 kilometers (8 miles) southeast of Tabiona, Utah; about 2,100 feet east and 540 feet south of the NW corner of sec. 21, T. 2 S., R. 6 W.; Blacktail Mountain USGS quad; Lat. 40 degrees 17 minutes 52 seconds N. and Long. 110 degrees 34 minutes 12 seconds W., WGS 84

RANGE IN CHARACTERISTICS:
Soil moisture regime is Ustic, oxyaquic subclass
Mean annual soil temperature: 6.5 to 8.0 degrees C, but can be as low as 5.5 degrees C at higher elevations.
Thickness of the mollic epipedon: 15 to 26 cm
Depth to cambic horizon: 25 to 50 cm
Depth to redox concentrations: 18 to 40 cm
The soil is endosaturated between the depths of 15 to 152 cm, during the months of April through November. The water table can be naturally occurring, or the result of irrigation.

Particle-size control section (weighted averages):
Clay content: 20 to 25 percent
Rock fragment content: 0 to 10 percent
Calcium carbonate content: 8 to 30 percent

A and Ap horizon(s):
Hue: 7.5YR or 10YR
Value: 3 to 5 dry, 2 or 3 moist
Chroma: 2 or 3
Texture: loam, silt loam, clay loam, or fine sandy loam
Clay content: 10 to 28 percent
Rock fragment content: 0 to 5 percent
Reaction: moderately alkaline (7.9-8.4)

Bw horizons:
Hue: 7.5YR or 10YR
Value: 4 to 6 dry, 3 to 5 moist
Chroma: 2 to 4
Texture: loam, clay loam, sandy clay loam, or silt loam
Clay content: 20 to 30 percent
Rock fragment content: 0 to 5 percent
Calcium carbonate equivalent: 20 to 30 percent
Reaction: moderately alkaline (7.8-8.4)

C or CB horizons:
Hue: 7.5YR or 10YR
Value: 5 to 7 dry, 4 to 6 moist
Chroma: 2 to 4
Texture: loamy sand, sandy loam, loam, or silty clay loam
Clay content: 6 to 28 percent
Rock fragment content: 0 to 15 percent
Calcium carbonate equivalent: 3 to 30 percent
Reaction: moderately alkaline (7.6-8.4)
Some pedons have lower horizons with hues of 2.5Y and up to 60 percent cobbles and gravels

COMPETING SERIES: This is the McManus series. McManus soils have visible secondary carbonates at a depth of 18 to 36 cm.

GEOGRAPHIC SETTING:
Parent material: alluvium derived from sedimentary rocks
Landform: stream terraces, floodplain-steps, or flood plains
Slopes: 0 to 4 percent
Elevation: 1,760 to 2,340 meters
Mean annual temperature: 5.5 to 7.0 degrees C, but can be as low as 4.5 degrees C at higher elevations.
Mean annual precipitation: Typically 300 to 410 mm, but can extend to 500 mm at higher elevations.
Precipitation pattern: Wettest months are October to May. Driest months are June to September.
Frost-free period: Typically 90 to 110 days, but can be as low as 70 days at higher elevations.
Flooding Frequency: Rare, with brief duration during the months of March to May

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Pescar and Dancehall series. The Dancehall soils are on alluvial fans and contain more than 35 percent coarse fragments in the particle size control section. The Pescar soils are on floodplains, are poorly drained, and have subsoils with greater than 35 percent coarse fragments.

DRAINAGE AND PERMEABILITY: somewhat poorly drained, low runoff, moderately slow permeability (0.2-0.6 in/hr)

USE AND VEGETATION: Peatross soils are primarily used for cropland and hayland. Native vegetation consists of Narrowleaf cottonwood, Blue wildrye, Basin wildrye, Drummond willow, and Chokecherry.

DISTRIBUTION AND EXTENT: Central Utah Mountains; LRR E, MLRA 48; LRU 48A. The series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES PROPOSED: Duchesne County, Utah, 2016; The name is taken from an old historic homestead.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: the zone from 25 to 100 cm. (lower part Bwb1, Ab, Bwb2, Bwb3, and upper part of C2 horizon).
Mollic epipedon: 0 to 18 cm depth. (Ap horizon).
Cambic horizon: 23 to 83 cm depth. (Bwb1, Ab, Bwb2, and Bwb3 horizons).

The assignment of the cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.

Taxonomic Version: Classified according to Keys to Soil Taxonomy, Twelfth Edition, 2014.

National Cooperative Soil Survey
U.S.A.