LOCATION STUNNER CO+NM WYEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Ustic Calciargids
TYPICAL PEDON: Stunner loam - grassland. (Colors are for dry soil unless otherwise noted.)
A--0 to 4 inches; light brownish gray (10YR 6/2) loam, dark grayish brown (10YR 4/2) moist; moderate very fine granular structure; soft, very friable; 3 percent gravel; many dark mineral grains in the sand and silt fractions; neutral (pH 7.2); clear smooth boundary. (2 to 5 inches thick)
BA--4 to 7 inches; brown (10YR 5/3) loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure parting to moderate medium granular; slightly hard, very friable; few thin clay films on peds and in root channels; 2 percent gravel; many dark colored magnetic mineral grains in the sand and silt fractions; neutral (pH 7.2); clear smooth boundary. (0 to 4 inches thick)
Bt--7 to 14 inches; brown (7.5YR 5/3) clay loam, brown (7.5YR 4/3) moist; moderate medium prismatic structure parting to moderate fine subangular blocky; slightly hard, very friable; peds are very hard; nearly continuous clay films on peds and in root channels; many dark colored magnetic mineral grains in the sand and silt fractions; slightly alkaline (pH 7.4); clear smooth boundary. (4 to 16 inches thick)
Bk1--14 to 25 inches; brown (7.5YR 5/3) clay loam, brown (7.5YR 4/3) moist; weak medium prismatic structure parting to weak medium subangular blocky; hard, friable; peds are very hard; thin clay skins on some faces of peds; discontinuous clay skins in root channels; many dark colored mineral grains in the sand and silt fractions; secondary calcium carbonate as concretions and in thin seams and streaks; violently effervescent; moderately alkaline (pH 8.2); gradual smooth boundary. (3 to 5 inches thick)
Bk2--25 to 36 inches; very pale brown (10YR 7/3) loam, pale brown (10YR 6/3) moist; massive; hard, friable; many dark colored mineral grains; secondary calcium carbonate as concretions and in thin seams and streaks much finely divided secondary carbonate; violently effervescent; moderately alkaline (pH 8.4); gradual wavy boundary. (8 to 24 inches thick)
Bk3--36 to 60 inches; pale brown (10YR 6/3) loam, brown (10YR 5/3) moist; massive; hard, friable; many dark colored mineral grains; secondary carbonate as concretions and in thin seams and streaks; strongly effervescent but with less carbonate than in the horizon above; moderately alkaline (pH 8.4).
TYPE LOCATION: Rio Grande County, Colorado; approximately 500 feet south and 500 feet west of the E1/4 corner of Sec. 13, T. 39 N., R. 6 E.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: is 41 to 46 degrees F (5.0 to 7.8 degrees C)
Mean summer soil temperature: is 61 to 66 degrees F (16.1 to 18.9 degrees C)
Exchangeable sodium: ranges from 0 to 15 percent
Electrical conductivity: conductivity: 0 to 14 millimhos within the epipedon and argillic horizon
Depth to uniformly calcareous material: 6 to 30 inches (15 to 76 centimeters)
Depth to the base of the argillic horizon: 10 to 40 inches (25 to 102 centimeters)
Depth to calcic horizon: 8 to 40 inches (20 to 102 centimeters)
Rock fragments: 0 to 30 percent in a major part of the solum and Bk horizons above a depth of 40 inches (102 centimeters) and fragments range in size from 1 to 10 inches (3 to 25 centimeters) in diameter.
A horizon:
Hue: 5Y to 7.5YR
Value: 4 to 6 dry, 3 or 4 moist
Chroma: 2 or 3
Reaction: slightly acid through moderately alkaline
Bt horizon:
Hue: 5Y to 7.5YR
Value: 3 to 6 dry, 3 to 5 moist
Chroma: 2 to 4
Texture: loam and clay loam
Reaction: slightly acid through moderately alkaline
Btk horizon (if present)
Hue: 5Y to 7.5YR
Value: 5 or 6 dry; 3 to 5 moist
Chroma: 3 or 4
Texture clay loam and loam
Calcium carbonate equivalent: 5 to 15 percent
Reaction: moderately alkaline
Bk or C: (if present)
Hue: 5Y to 7.5YR
Value: 5 to 8 dry, 4 to 7 moist
Chroma: 2 to 4.
Clay content: 18 to 35 percent
Sand content: 15 to 35 percent fine or coarser sand
Calcium carbonate equivalent: 15 to 50 and decreases with depth
Reaction: moderately through strongly alkaline
COMPETING SERIES: These are the
Alogia (WY),
Anchutz (WY),
Antonito (NM),
Cushool (WY),
Cutback (WY),
Fluetsch (CO),
Fonce (CO),
Grubrob (CO),
Hickey (UT),
Potrio (CO),
Rock River (CO),
Trinchera (CO) and
Wycolo (WY) series.
Alogia soils have secondary gypsum and have a fluctuating seasonal water table at 40 to 60 inches.
Anchutz, Hickey and Rock River soils: have more than 35 fine percent fine sand or coarser throughout the Bt and Bk horizons.
Antonito and Grubrob soils: have a lithic contact above 40 inches
Cushool soils: have a paralithic contact at 20 to 40 inches.
Cutback soils: can have a lithologic discontinuity consisting of tuffaceous skeletal material at 15 to 24 inches (38 to 61 centimeters).
Fluetsch soils: have more than 35 percent fine or coarser sand in the argillic horizon.
Fonce soils: have more than 35 percent fine sand and coarser sand in the particle control section and have loamy-skeletal substratum above 40 inches.
Potrio soils: have lithic contact at 40 to 60 inches
Trinchera soils: do not have rock fragment content that ranges from 15 to 30 percent in the solum.
Wycolo soils: have a paralithic contact at depths of 20 to 40 inches.
GEOGRAPHIC SETTING:
Parent material: formed in thick calcareous medium to moderately fine alluvium and eolian deposits derived principally from basic igneous materials, limestone and sandstone and outwash derived from granite, gneiss, and schist.
Landform: alluvial fans, outwash fans, fan remnants, plateaus and valley filling side slopes.
Slopes: 1 to 20 percent
Elevation: is 6,500 to 8,500 feet (1,981 to 2,591 meters)
Mean annual air temperature: 39 to 45 degrees F (3.9 to 7.2 degrees C)
Mean annual precipitation: 8 to 15 inches (203 to 381 millimeters)
Precipitation pattern: Peak periods of precipitation in spring and early summer
Mean summer temperature: 60 to 64 degrees F (15.5 to 17.8 degrees C)
Frost-free period: ranges from 75 to 110 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Platoro,
Kibin,
Trinchera, and
Villa Grove soils.
Platoro soils have sand and gravel substratums above a depth of 40 inches and lack calcic horizons.
Kibin soils are pachic.
Villa Grove soils have a mollic epipedon and lack a calcic horizon.
Trinchera soils have more than 35 fine percent fine sand or coarser throughout the Bt and Bk horizons.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate or moderately slow permeability.
USE AND VEGETATION: These soils are used principally as native pastureland or for irrigated cropland. Native plants are snakeweed, blue grama, winterfat, and ring muhly.
DISTRIBUTION AND EXTENT: San Luis Valley Area of south-central Colorado, northwestern Colorado, New Mexico and Wyoming; LRR E, MLRA 51 at the type location, and 48A; LRR D, MLRA 34, 36. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Rio Grande County, Colorado, 1972.
REMARKS: Diagnostic features include an argillic horizon at 7 to 14 inches and a calcic horizon from 14 to 36 inches.
Last updated by the state 2/99
Taxonomic version: Tenth edition, 2006