LOCATION PACON                   UT

Established Series
Rev. LDS/JWB
04/2011

PACON SERIES

The Pacon series consists of shallow, well drained soils that formed in colluvium and/or slope alluvium over residuum weathered from limestone, sandstone and shale. Pacon soils are on structural benches. Slopes range from 2 to 15 percent. Mean annual precipitation is about 25 centimeters and the mean annual temperature is about 8.9 degrees C.

TAXONOMIC CLASS: Loamy, mixed, superactive, mesic Lithic Ustic Haplocalcids

TYPICAL PEDON: Pacon gravelly fine sandy loam, on a southwest facing, structural bench, 6 percent slope in rangeland, at an elevation of 1844 meters. (Colors are for dry soil unless otherwise noted.) When described on May 11 1992 the soil was dry to 13 centimeters and moist below. The surface is covered by 20 percent gravel, and 5 percent cobbles.

A--0 to 8 centimeters; light brown (7.5YR 6/3) gravelly fine sandy loam, brown (7.5YR 4/3) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine, fine and medium, few coarse roots; about 20 percent gravel and 3 percent cobbles, slightly effervescent, (3 percent calcium carbonate equivalent), carbonates are disseminated; moderately alkaline (pH 7.9); abrupt wavy boundary. (5 to 13 centimeters thick)

Bw--8 to 20 centimeters; brown (7.5YR 5/4) loam, strong brown (7.5YR 4/6) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and plastic; common very fine, fine and medium, few coarse roots; about 10 percent gravel and 1 percent cobbles; slightly effervescent, (6 percent calcium carbonate equivalent), carbonates are disseminated; moderately alkaline (pH 8.2); clear wavy boundary. (5 to 18 centimeters thick)

Bk--20 to 38 centimeters; light brown (7.5YR 6/4) gravelly loam, brown (7.5YR 4/4) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and plastic; common very fine, fine and medium, few coarse roots; about 15 percent gravel and 2 percent cobbles; strongly effervescent, (17 percent calcium carbonate equivalent), carbonates occur as pendants on rock fragments and common fine threads; moderately alkaline (pH 8.4); clear wavy boundary. (10 to 23 centimeters thick)

BCk--38 to 48 centimeters; pink (7.5YR 7/4) gravelly loam, brown (7.5YR 5/4) moist; massive; slightly hard, friable, slightly sticky and plastic; common very fine, fine and medium, few coarse roots; about 15 percent gravel, 5 percent channers and 5 percent cobbles; violently effervescent, (23 percent calcium carbonate equivalent), carbonates occur as pendants on rock fragments, coatings on bedrock and as common to many fine threads; moderately alkaline (pH 8.4); abrupt wavy boundary. (0 to 13 centimeters thick)

R--48 to 58 centimeters; interbedded sandstone and limestone.


TYPE LOCATION: Emery County, Utah; about one mile north west of Flat Top mountain; located about 2,400 feet west and 150 feet north of the SE corner of sec. 17, T. 17 S., R. 12 E.; Flattop Mountain USGS quad; lat. 39 degrees 20 minutes 19 seconds N. and long. 110 degrees 35 minutes 41 seconds W., NAD 83

RANGE IN CHARACTERISTICS:

Soil moisture: The soil moisture control section is affected by precipitation that peaks from July to October and falls evenly throughout the remainder of the year; aridic (torric) moisture regime bordering on ustic.
Mean annual soil temperature: 8.3 to 11.1 degrees C
Depth to lithic contact: 25 to 51 centimeters to sandstone or limestone
Depth to calcic horizon: 10 to 25 centimeters

Particle-size control section (weighted average):
Clay content: 18 to 27 percent
Sand content: 35 to 70 percent
Rock fragments: 15 to 35 percent

A horizon:
Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 to 4
Texture: gravelly fine sandy loam, gravelly loam or very bouldery loam
Clay content: 12 to 27 percent
Rock fragments: 15 to 60 percent
Calcium carbonate equivalent: 1 to 15 percent
EC (mmhos/cm): 0 to 2
SAR: 0 to 2
Reaction: slightly or moderately alkaline

Bw horizon:
Hue: 7.5YR or 10YR
Value: 5 to 7 dry, 4 or 5 moist
Chroma: 3 to 6
Texture: loam, bouldery loam
Clay content: 15 to 27 percent
Rock fragments: 0 to 35 percent
Calcium carbonate equivalent: 2 to 15 percent
EC (mmhos/cm): 0 to 2
SAR: 0 to 2
Reaction: slightly or moderately alkaline

Bk horizon:
Hue: 7.5YR to 2.5Y
Value: 6 or 7 dry, 4 to 6 moist
Chroma: 2 to 6
Texture: gravelly loam, clay loam, very channery fine sandy loam
Clay content: 15 to 35 percent
Rock fragments: 0 to 50 percent
Calcium carbonate equivalent: 15 to 45 percent
EC (mmhos/cm): 0 to 4
SAR: 0 to 2
Reaction: moderately or strongly alkaline

BCk horizon:
Hue: 7.5YR to 2.5Y
Value: 6 or 8 dry, 5 to 7 moist
Chroma: 2 to 4
Texture: very channery loam
Clay content: 18 to 27 percent
Rock fragments: 35 to 50 percent mostly angular gravel and channers
Pararock fragments: 0 to 10 percent soft sandstone or shale
Calcium carbonate equivalent: 15 to 40 percent
EC (mmhos/cm): 0 to 4
Gypsum: 0 to 2 percent
SAR: 0 to 4
Reaction: moderately alkaline

COMPETING SERIES: These are the Petaca, Pinon, Shalako and Wayneco series.
Petaca soils formed in material weathered from basalt
Shalako and Wayneco soils have less than 18 percent clay in the particle size control section
Pinon soils have a mean annual soil temperature of 11.1 to 13.9 degrees C.

GEOGRAPHIC SETTING:
Parent material: coluvium and/or slope alluvium over residuum derived from mixed sedimentary rocks mostly calcareous sandstone or limestone with some shale.
Landform: Cuestas, mesas, structural benches and ridges
Slopes: 2 to 20 percent
Elevation: 1524 to 2195 meters
Mean annual temperature: 7.2 to 10.0 degrees C
Mean annual precipitation: 229 to 305 millimeters
Precipitation pattern: peak periods between July to October and evenly distributed throughout the remainder of the year.
Frost-free period: 120 to 150 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gerst, Lazear and Molen series. The Gerst soils are shallow to soft shale and are on side slopes of shale hills. The Lazear soils lack a calcic horizon and are in more convex positions. The Molen soils are moderately deep and are in more concave positions.

DRAINAGE AND PERMEABILITY: Well drained, Medium runoff, Moderate permeability.

USE AND VEGETATION: These soils are used as rangeland. Potential vegetation is Salina wildrye, galleta and Indian rice grasses, shadscale, fourwing saltbush, Utah Juniper, pinyon pine and black sagebrush. This soil has been correlated to the Semidesert shallow loam (Salina wildrye) R034XY230UT and Semidesert shallow loam (Utah juniper-pinyon) R034XY233UT range sites in Utah.

DISTRIBUTION AND EXTENT: Eastern Utah; LRR D, MLRA 34B; moderate extent.

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

SERIES ESTABLISHED: Emery County, Utah, Emery area soil survey, Utah, 2011. The name Pacon is coined from Pace Canyon in the soil survey area.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: The zone from 10 to 48 centimeters. (Bk and BCk horizons)
Ochric epipedon: The zone from 0 to 8 centimeters. (A horizon)
Calcic horizon: The zone from 8 to 48 centimeters. (Bk and BCk horizons)
Lithic contact: The contact with interbedded sandstone and limestone at 48 centimeters. (R horizon)

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

Taxonomic Version: Eleventh Edition, 2010

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National Cooperative Soil Survey
U.S.A.