LOCATION SELPATS WYEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Ustic Calciargids
TYPICAL PEDON: Selpats sandy clay loam -- on a south facing convex slope of one percent, in a cultivated field. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 25 centimeters (0 to 10 inches); brown (10YR 5/3) sandy clay loam, brown (10YR 4/3) moist; moderate coarse clods parting to weak fine subangular blocky structure; slightly hard, very friable, sticky and plastic; many very fine and few fine roots; common fine discontinuous irregularly shaped pores; slightly alkaline (pH 7.8); abrupt smooth boundary. (15 to 28 centimeters (6 to 11 inches) thick)
Bt1--25 to 36 centimeters (10 to 14 inches); brown (10YR 5/3) sandy clay loam, brown (10YR 4/3) moist; weak fine and medium subangular blocky structure parting to weak very fine and fine subangular blocky; slightly hard, friable, sticky and plastic; common fine and very fine and few medium roots; few very fine continuous vesicular pores; few distinct clay films on faces of peds and bridging of mineral grains; slightly alkaline (pH 7.6); clear wavy boundary.
Bt2--36 to 48 centimeters (14 to 19 inches); pale brown (10YR 6/3) clay loam, brown (10YR 5/3) moist; weak medium and coarse prismatic structure parting to moderate fine and medium subangular blocky; hard, friable, sticky and plastic; common very fine and few fine roots; many very fine and few fine continuous vesicular pores; many prominent clay films on faces of peds and in pores; slightly alkaline (pH 7.6); clear irregular boundary. (Combined thickness of the Bt horizon is 10 to 30 centimeters (4 to 12 inches) thick)
Btk--48 to 61 centimeters (19 to 24 inches); pale brown (10YR 6/3) loam, brown (10YR 5/3) moist; weak medium and coarse prismatic structure parting to weak fine subangular blocky; hard, friable, slightly sticky and slightly plastic; common very fine roots; many very fine, common fine and few medium continuous vesicular pores; few distinct clay films on faces of peds and in pores; strong effervescence; calcium carbonate as few distinct soft masses and seams; moderately alkaline (pH 8.0); gradual wavy boundary. (13 to 33 centimeters (5 to 13 inches) thick)
2Bk--61 to 152 centimeters (24 to 60 inches); very pale brown (10YR 7/3) very gravelly sandy loam, brown (10YR 5/3) moist; massive; slightly hard, very friable, nonsticky and slightly plastic; few very fine roots; violent effervescence; calcium carbonate as common prominent soft masses, seams and pendants on the undersides of rock fragments; 35 percent gravel and 5 percent cobbles; moderately alkaline (pH 8.2).
TYPE LOCATION: Platte County, Wyoming; 640 meters (2100 feet) north and 335 meters (1100 feet) west of the southeast corner of section 9, T 24 N, R 68 W., 42 degrees 3 minutes 56 seconds north latitude and 105 degrees 0 minutes 19 seconds west longitude.
RANGE IN CHARACTERISTICS:
Base of the argillic horizon: 30 to 64 centimeters (12 to 25 inches)
Skeletal lithologic discontinuity: 38 to 99 centimeters (15 to 39 inches)
Rock fragment content: typically 0 to 5 percent above the discontinuity and 35 to 70 percent below
Moisture control section: dry for more than half of the time cumulative that the soil temperature at a depth of 51 centimeters (20 inches) is 5 degrees C. (41 degrees F.) or warmer
Moisture control section: dry for at least 60 consecutive days from July 1 to October 15 and 90 cumulative days during this period.
Average annual soil temperature: 8 to 11 degrees C. (47 to 51 degrees F.)
A or Ap horizon:
Hue: 10YR
Value: 4 or 5, 3 or 4 moist
Chroma: 3 or 4
Texture: fine sandy loam, sandy clay loam or gravelly sandy loam
Reaction: moderately alkaline
Bt horizon:
Hue: 10YR
Value: 5 or 6, 4 or 5 moist
Chroma: 3 or 4
Texture: sandy clay loam, clay loam, gravelly modifiers occur in some areas
Btk and Bk horizons:
Hue: 10YR
Value: 5 or 6
Chroma: 3 or 4
Texture: very fine sandy loam, loam or gravelly sandy loam
Calcium carbonate equivalent: 9 to 14 percent
2Bk horizon:
Hue: 10YR
Value: 6 or 7, 5 to 7 moist
Chroma: 3 or 4
Calcium carbonate equivalent: 8 to 30 percent and decreases with depth
COMPETING SERIES: These are the
Alvey,
Barx,
Cerrillos,
Clovis,
Fernando,
Flaco,
Horchata,
Los Alamos,
Maysdorf, Millet,
Palabria,
Progresso,
Sanostee,
Scholle,
Solirec,
Spenlo,
Threetop,
Tuweep and
Wineg.
Alley and Solirec soils do not have a skeletal lithologic discontinuity.
Barx, Cerrillos, Clovis, Fernando, Los Alamos, Maysdorf, Scholle, Spenlo,
Flaco, Horchata, Palabria, Progresso, Sanostee and Threetop soils have a lithic contact.
Millet and Tuweep soils are intermittently moist in some part of the moisture control section from July 1 to October 15.
Wineg soils consist of mixed alluvium dominantly from granite, basalt, schist and sandstone.
GEOGRAPHIC SETTING:
Landform: hillslopes, plateaus and stream terraces
Parent material: alluvium and eolian deposits
Slopes are 0 to 6 percent
Elevation: 1311 to 1676 meters (4300 to 5500 feet)
Average annual precipitation: 36 to 41 centimeters (14 to 16 inches)
Average annual air temperature: 8 to 9 degrees C. (46 to 48 degrees F.)
Frost-free period: 115 to 130 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Clapper,
Forkwood,
Hiland,
Recluse, and
Sweatbee soils.
Clapper soils are on terrace treads and have a loamy-skeletal particle size control section and are calcareous throughout the profile.
Forkwood, Hiland and Recluse lack skeletal textures within 60 inches and occur on similar landscapes.
Recluse soils also have a mollic epipedon.
Sweatbee soils have a coarse-loamy particle size control section and are on similar landscapes.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage: well drained
Runoff: medium
Saturated Hydraulic Conductivity: moderately high
USE AND VEGETATION: These soils are used mainly for dry fallow and irrigated cropland, hayland, rangeland and wildlife habitat.
The native vegetation is needleandthread, western wheatgrass, prairie junegrass, threadleaf sedge and silver sagebrush.
Wheat and oats are the principal crops grown on dryland.
Short season corn, sugar beets, beans and alfalfa are the principal crops grown on irrigated cropland.
DISTRIBUTION AND EXTENT: Selpats soils occur in eastern Wyoming. This series is of limited extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Platte County, Wyoming, 1989
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: 0 to 25 centimeters (0 to 10 inches) (Ap)
Argillic horizon: 25 to 48 centimeters (10 to 19 inches) (Bt1,Bt2)
Calcic horizon: 61 to 155 centimeters (24 to 60 inches) (2Bk)
SIR- WY1009
LRR = G
Modified format by LRM in 3/2006 to include metric conversion, update competing series and change permeability to saturated hydraulic conductivity.