LOCATION PESCAR                  CO+UT WY

Established Series
Rev. RFB/JPP/SJJ
02/2016

PESCAR SERIES

The Pescar series consists of very deep, poorly drained soils that formed in stratified calcareous alluvium derived from mixed sources. Pescar soils are on flood plains. Slopes range from 0 to 4 percent. Mean annual precipitation is about 20 inches (510 mm) and mean annual temperature is about 42 degrees F. (5.5 deg. C).

TAXONOMIC CLASS: Coarse-loamy over sandy or sandy-skeletal, mixed, superactive, calcareous, frigid Aquic Ustifluvents

TYPICAL PEDON: Pescar loam, on a south facing, simple, 1 percent slope in grassland at an elevation of 6,350 feet (1,936 m). (Colors are for dry soil unless otherwise noted.)

A--0 to 20 cm; light brownish gray (10YR 6/2) loam stratified with thin lenses of loamy fine sand, dark grayish brown (10YR 4/2) moist; moderate fine granular structure; soft, very friable; strongly effervescent; slightly alkaline; clear smooth boundary. (10 to 30 cm thick)

Cg--20 to 56 cm; pale brown (10YR 6/3) loam stratified with loamy fine sand, brown (10YR 5/3) moist; common medium distinct redox features of yellowish brown (10YR 5/6) moist, and gray (N 6/0) moist; massive; soft, very friable; strongly effervescent; slightly alkaline; clear wavy boundary. (15 to 56 cm thick)

2C--56 to 152 cm; pale brown (10YR 6/3) very gravelly sand stratified with lenses of loamy sand, brown (10YR 5/3) moist; common medium distinct redox features of yellowish brown (10YR 5/6) moist; single grain; loose; 45 percent gravel, strongly effervescent; moderately alkaline.

TYPE LOCATION: Archuleta County, Colorado; about 4 miles south of Piedra, Colorado; located in the NW 1/4 section 25, T. 34 N., R. 5 W.; Chimney Rock USGS quad; lat. about 37 degrees 10 minutes 00 seconds N. and long. about 107 degrees 20 minutes 48 seconds W., NAD 27

RANGE IN CHARACTERISTICS:
Soil moisture regime: Ustic, transitional to aquic.
Mean annual soil temperature: 44 to 47 degrees F. (6.5-8.0 deg. C)
Mean summer soil temperature: 59 to 63 degrees F. (15.0-17.0 deg. C)
Depth to calcareous material: 0 to 10 inches (0 to 25 cm)
Depth to sandy-skeletal material: 18 to 30 inches (46 to 76 cm)
Depth to endosaturation: 8 to 20 inches (20 to 50 cm)

Particle-size control section:
Clay content: 5 to 18 percent in the upper part, 0 to 5 percent in the lower part.
Content of fine and coarser sand: 40 to 50 percent in the upper part.
Rock fragment content: 0 to 10 percent in the upper part, 35 to 80 percent in the lower part.

A horizon:
Hue: 7.5YR to 5Y
Value: 5 to 7 dry, 4 to 6 moist
Chroma: 1 to 4, dry and moist
Texture: L or FSL
Rock fragment content: 0 to 10 percent
Calcium carbonate equivalent: 0 to 5 percent
Reaction: neutral or slightly alkaline

Cg horizon:
Hue: 7.5YR to 5Y
Value: 6 or 7 dry, 4 or 5 moist
Chroma: 2 or 3, dry and moist
Texture: stratified loam to loamy fine sand
Rock fragment content: 0 to 10 percent
Calcium carbonate equivalent: 0 to 5 percent
Reaction: neutral to moderately alkaline

2C horizon (2Cg in some pedons):
Hue: 5Y to 7.5YR
Value: 6 or 7 dry, 4 or 5 moist
Chroma: 2 or 3, dry and moist
Texture: GRV-S, GRV-LS, GRX-S
Rock fragment content: 35 to 80 percent
Calcium carbonate equivalent: 0 to 5 percent
Reaction: neutral to moderately alkaline

COMPETING SERIES: There are currently no other series in this family. The Green River soil is similar but is coarse-loamy.

GEOGRAPHIC SETTING:
Parent material: stratified calcareous alluvium derived from mixed sources.
Landform: flood plains
Slopes: 0 to 4 percent
Elevation: 6,500 to 8,000 feet (1,980-2,440 m)
Mean annual air temperature: 42 to 45 degrees F. (5.5-7.0 deg. C)
Mean annual precipitation: 18 to 22 inches (460-560 mm)
Wettest months: July and August.
Driest months: May and June.
Frost-free period: 90 to 110 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Carracas and Rogert soils. Both are on hill slopes.
Carracas soils have a paralithic contact within 50 cm of the surface.
Rogert soils have a lithic contact within 50 cm of the surface.

DRAINAGE AND PERMEABILITY: Poorly drained; low or very low runoff; moderately rapid permeability. These soils are frequently flooded for brief periods during the months of April to September.

USE AND VEGETATION: Used for livestock grazing. Native vegetation is tufted hairgrass, bluegrass, western wheatgrass, slender wheatgrass, clover, cottonwood, baltic rush, sedges, clematis and willows.

DISTRIBUTION AND EXTENT: Southwestern Colorado, Southern Wyoming and Northern Utah. LRR E, MLRA 48A and 47. This series is of moderate extent.

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

SERIES ESTABLISHED: Archuleta County (Piedra Area), Colorado, 1974. The name is taken from a creek.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from 0 to 20 cm. (A horizon)
Aquic feature: Based on redox depletions and seasonal saturation, 20 to 56 cm horizon (Cg horizon)
Redox concentrations: The zone from 20 to 152 cm. (Cg and 2C horizons)
Redox depletions: The zone from 20 to 56 cm. (Cg horizon)
Endosaturation: The presence of an apparent water table (upper boundary) at 20 cm during the months of March to June.
Particle size control section: The zone from 25 to 100 cm. (parts of the Cg and 2C horizons)

A revision in 06/2002 changed the depth to saturation from 46 to 76 cm, to 20 to 50 cm. This restricted this soil to the Aquic subgroup, and excludes Oxyaquic.

Keys to Soil Taxonomy: Classified according to the Eighth Edition, 1998

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National Cooperative Soil Survey
U.S.A.