LOCATION OTERO CO+KS NE NM OK WYEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, calcareous, mesic Aridic Ustorthents
TYPICAL PEDON: Otero sandy loam - grassland. (Colors are for dry soil unless otherwise noted.)
A--0 to 15 centimeters (0 to 6 inches); grayish brown (10YR 5/2) sandy loam, dark grayish brown (10YR 4/2) moist; weak very fine granular structure; soft, very friable; strongly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (8 to 20 centimeters (3 to 8 inches) thick)
AC--15 to 36 centimeters (6 to 14 inches); light brownish gray (10YR 6/2) sandy loam, dark grayish brown (10YR 4/2) moist; very weak medium subangular blocky structure parting to weak coarse granular; soft, very friable; strongly effervescent; moderately alkaline (pH 8.0); gradual smooth boundary. (0 to 23 centimeters (0 to 9 inches) thick)
C--36 to 152 centimeters (14 to 60 inches); very pale brown (10YR 7/3) sandy loam, brown (10YR 5/3) moist; massive; slightly hard, very friable; secondary calcium carbonate occurring discontinuously and at variable depths in the form of soft masses, and in thin seams and streaks; violently effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Baca County, Colorado; approximately 563 meters (1,848 feet) west and 61 meters (200 feet) north of the southeast corner of Sec. 6, T. 31 S., R. 50 W.
RANGE IN CHARACTERISTICS:
Soil moisture: moist in some part of the moisture control section for about 40 to 90 cumulative days while the soil temperature is 5 degrees C. (41 degrees) or higher; moist intermittently April though August
Moisture regime: ustic bordering on aridic
Mean annual soil temperature: 8 to 14 degrees C. (47 to 58 degrees F.)
Mean summer soil temperature: 15 to 26 degrees C. (59 to 79 degrees F.)
Depth to secondary calcium carbonate: at the surface, but are noncalcareous for 3 to 25 centimeters (1 to 10 inches) in some pedons.
The weighted average organic carbon content surface 15 inches: 0 to 1 percent, and the organic carbon decreases uniformly with increasing depth
Sand/clay ratios: 3 to 15
Particle size control section:
Clay content: 5 to 18 percent
Silt content: 5 to 35 percent
Sand content: 50 to 82 percent, with 15 to 35 percent being fine or coarser sand
Rock fragment content: typically less than 2 percent, ranges from 0 to 15 percent.
A horizon or AC (if present):
Hue: 7.5YR to 5Y
Value: 4 to 7, and 3 to 6 moist
Chroma: 2 to 4
Where the value is as dark as 5 dry and 3 moist, the horizon is too thin or contains too little organic matter to be a mollic epipedon.
Reaction: neutral to moderately alkaline
Texture: typically sandy loam but includes fine and very fine sandy loams, loam, loamy very fine sand, and loamy fine sand
C horizon:
Hue: 7.5YR to 5YR
Value: 6 or 7, 4 to 6 moist
Chroma: 3 or 4
Calcium carbonate equivalent: 0 to 4 percent
Amount and distribution of visible secondary calcium carbonate is erratic.
Texture: fine sandy loam, sandy loam, and loamy very fine sand.
COMPETING SERIES: These are the
Ashollow,
Lindrith, and
Pitchdraw series.
Ashollow soils formed in residuum from sandstone and do not have visible secondary calcium carbonate in the control section.
Lindrith soils are dry in
May and June.
Pitchdraw soils have a paralithic contact at depths of 51 to 102 centimeters (20 to 40 inches).
GEOGRAPHIC SETTING:
Landscape: hills, and alluvial plains
Landform: fans, blowouts, terraces, hills, ridges, and plains (Surfaces are frequently wind-reworked and have a low dune-like relief)
Slopes: 0 to 20 percent.
Parent material: alluvial sediments that have been wind-modified in many places
Mean annual precipitation: 33 to 43 centimeters (13 to 17 inches), with peak periods of precipitation during April through August
Mean annual air temperature: 9 to 12 degrees C. (48 to 54 degrees F.)
Mean summer temperature: 20 to 23 degrees C. (68 to 74 degrees F.)
Frost free period: 120 to 165 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Mitchell,
Nelson,
Olnest, and
Vona soils.
Mitchell soils are coarse-silty.
Nelson soils have an ustic aridic moisture regime.
Olnest and Vona soils have an argillic horizon.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage well or somewhat excessively drained
Runoff: low to medium
Saturated hydraulic conductivity: high
USE AND VEGETATION: These soils are used for native rangeland or for dry and irrigated cropland.
Native vegetation consists of tall and short grass associations with some yuccas and sand sage.
DISTRIBUTION AND EXTENT: Eastern Colorado, western Nebraska, and southeastern Wyoming. LRR G, MLRA 67; The series is of large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Arkansas Valley Area, Colorado, 1926.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: 0 to 15 centimeters (0 to 6 inches) (A horizon)
The classification is revised from an Ustic Torriorthent to an Aridic Ustorthent. Last updated by the state 3/94.
Changes to the moisture pattern reflect peak periods of precipitation at the type location in Baca County, Colorado.
Modified by Lee Neve in January 2002 to make changes in the format to semitab.
Taxonomic Version: Second Edition, 1999
Modified format by LRM in 1/2006 to include metric conversion and change permeability to saturated hydraulic conductivity.