LOCATION PESOWYO                 WY SD

Established Series
Rev. JWW
06/2011

PESOWYO SERIES

The Pesowyo series consists of moderately deep, well drained soils formed in residuum derived primarily from limestone and calcaeous sandstone. They are on mountain hillslopes. Slopes range from 6 to 60 percent. The average annual precipitation is about 455 mm and the average annual temperature is about 6 degrees c.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Typic Haplustolls

TYPICAL PEDON: Pesowyo channery clay loam, on a south facing hillslope of 6 percent in a ponderosa pine savannah.

Oi--0 to 2 cm; decomposing forest litter.

A--2 to 15 cm; very dark grayish brown (10YR 3/2) channery clay loam, black (10YR 2/1) moist; moderate medium granular structure; soft, friable, slightly sticky and nonplastic; common fine and coarse roots; 20 percent channers; slightly alkaline; clear, smooth boundary. (10 to 20 cm thick)

Bw--15 to 41 cm; dark grayish brown (10YR 4/2) very channery clay loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; slightly hard, firm, sticky and plastic; common fine and coarse roots; 35 percent channers; slight effervescence in lower part; slightly alkaline; clear, smooth boundary. (18 to 30 cm thick)

Bk--41 to 61 cm; light yellowish brown (10YR 6/4) very channery clay loam, dark yellowish brown (10YR 4/4) moist; massive; slightly hard, firm, sticky and plastic; few fine and coarse roots; 50 percent gravel and channers; carbonates occur as common medium soft masses and common fine filaments; strong effervescence; moderately alkaline; abrupt wavy boundary. (23 to 59 cm thick)

R--61 cm; hard, fractured limestone.

TYPE LOCATION: Weston County, Wyoming; 1,980 feet east and 330 feet north of the southwest corner of Sec. 18, T. 48 N., R. 61 W.

RANGE IN CHARACTERISTICS:
Thickness of mollic epipedon: 18 to 38 cm


Particle-size control section (weighted average):
Clay content: 18 to 35 percent
Rock fragments: 35 to 60 percent limestone and/or sandstone channers

A horizon
Hue: 10YR or 2.5Y
Value: 3 or 4, 2 or 3 moist
Chroma: 1 or 2
Texture: L, CL (fine-earth fraction)
Reaction: neutral to moderately alkaline

Bw horizon
Hue: 10YR or 2.5Y
Value: 3 to 5, 2 or 3 moist
Chroma: 2 or 3
Texture: L,CL (fine-earth fraction)
Reaction: neutral to moderately alkaline

Bk horizon
Hue: 10YR or 2.5Y
Value: 5 to 7, 4 or 5 moist
Chroma: 2 to 4
Texture: L, CL (fine-earth fraction)
Calcium carbonate equivalent: 8 to 15 percent
Reaction: moderately or strongly alkaline

R horizon
Very strongly cemented to indurated limestone and/or calcareous sandstone

COMPETING SERIES:
Aguja - formed in colluvium derived from tuff; moderately deep to paralithic contact
Finleypoint, Flott, Labre, Perma, Renegade, Sandia, Slimbutte, Subwell, Towave, Vigilante, Walstead, Wanagan, Wimper - depth to bedrock is greater than 100 cm
Kutler - formed in residuum derived from grus
Peso - moisture control section is the driest in April, May, and June; has 70 to 90 percent coarse fragments in the particle-size control section
Veatch - have 8 to 18 percent clay in the particle-size control section

GEOGRAPHIC SETTING:
Parent material: slope wash and reworked residuum weathered from limestone
Landform: structural benches, bedrock-controlled dipslopes, and high fan aprons
Landscape: mountains
Slopes: 3 to 60 percent
Elevation: 1,280 to 1,890 meters
Mean annual air temperature: 4 to 8 degrees C
Mean annual precipitation: 405 to 510 mm
Precipitation pattern: In most years, more than half of the annual precipitation occurs as snow and rain from April through July
Frost-free period: 80 to 110 days

GEOGRAPHICALLY ASSOCIATED SOILS:
Cordeston - are very deep and fine-loamy; they occur in valleys and drainageways below Pesowyo soils
Corpening and Rockerville (T) - are shallow to hard bedrock; additionally Corpening siols have less than 35 percent rock fragments throughout; they occur on similar landscape positions as Pesowyo

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; slow to rapid runoff, depending on slope; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Pesowyo soils are used for livestock grazing, wildlife habitat, and recreation. Native vegetation consists of scattered Ponderosa pine and juniper, along with Columbia needlegrass, western wheatgrass, sedges, snowberry, prairie thermopsis, and serviceberry.

DISTRIBUTION AND EXTENT: Pesowyo soils occur on the Limestone Bench, High Precipitation and Red Valley, High Elevation physiographic areas of the Black Hills Foothills (MLRA 61), and on the Mixed Low Limestone Plateau and Low Limestone Plateua, High Precipitation physiographic areas of the Black Hills (MLRA 62); LRR G; South Dakota and Wyoming. The series is of limited extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado

SERIES ESTABLISHED: Weston County, Wyoming; 1983.

REMARKS
Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: The zone from 25 to 61 cm (Bw and Bk horizons)
Mollic epipedon: The zone from 0 to 41 cm (Oi, A and Bw horizons)
Lithic contact: 61 cm (R horizon)
Other features: Common medium soft masses and common fine filaments of secondary calcium carbonate (Bk horizon)

Taxonomic Version: Keys to Soil Taxonomy, Eleventh Edition, 2010

---

National Cooperative Soil Survey
U.S.A.