LOCATION PICABO IDEstablished Series
TAXONOMIC CLASS: Coarse-silty, carbonatic, frigid Oxyaquic Calcixerolls
TYPICAL PEDON: Picabo silt loam--on a 1 percent slope at an elevation of 4,900 feet in rangeland. When described October 5, 1983, the profile was moist throughout. (Colors are for dry soil unless otherwise noted.)
Ak--0 to 4 inches; grayish brown (10YR 5/2) silt loam, dark brown (10YR 3/3) moist; weak very fine and fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and common fine roots; many very fine and fine interstitial and few very fine tubular pores; strongly effervescent (44 percent calcium carbonate); strongly alkaline (pH 8.8); gradual wavy boundary. (3 to 7 inches thick)
ABk--4 to 9 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak very thin and thin platy structure, parting to weak very fine granular; soft, very friable, slightly sticky and slightly plastic; common very fine and few fine and medium roots; many very fine and few fine interstitial pores; strongly effervescent (49 percent calcium carbonate); strongly alkaline (pH8.5); clear smooth boundary. ( 5 to 8 inches thick)
Bk1--9 to 16 inches; light brownish gray (10YR 6/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak thin and medium platy structure parting to weak very fine and fine granular; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and few fine and medium roots; few very fine tubular and common very fine and fine interstitial pores; strongly effervescent (60 percent calcium carbonate); moderately alkaline (pH 8.3); clear wavy boundary. (5 to 10 inches thick)
Bk2--16 to 23 inches; light gray (10YR 7/1) loam, gray (10YR 5/1) moist; weak very fine and fine subangular blocky structure; slightly hard, very friable, sticky and plastic; common very fine and few fine and medium roots; few very fine interstitial, common very fine and few fine tubular pores; violently effervescent (66 percent calcium carbonate); moderately alkaline (pH 8.0); gradual wavy boundary. (5 to 9 inches thick)
Bkg1--23 to 32 inches; light gray (10YR 7/1) silt loam, gray (10YR 6/1) moist; weak very fine, fine and medium subangular blocky structure; hard, friable, moderately sticky and moderately plastic; few very fine, fine and medium roots; common very fine and fine tubular pores; violently effervescent (66 percent calcium carbonate); moderately alkaline (pH 8.0); gradual wavy boundary. (6 to 12 inches thick)
Bkg2--32 to 39 inches; light gray (10YR 7/1) silt; gray (10YR 5/1) moist; weak very fine, fine and medium subangular blocky structure; hard friable, moderately sticky and moderately plastic; few very fine roots; common very fine tubular pores; about 5 percent pebble sized irregular shaped calcium carbonate cemented concretions; violently effervescent (69 percent calcium carbonate); moderately alkaline (pH 7.9); abrupt smooth boundary. (5 to 9 inches thick)
2Bkg3--39 to 51 inches; white (5Y 8/1) gravelly silt loam, light gray (5Y 7/2) moist; massive; very hard, firm, moderately sticky and moderately plastic; few very fine roots; common fine tubular pores; 30 percent pebble sized irregular shaped calcium carbonate cemented concretions; violently effervescent (77 percent calcium carbonate); moderately alkaline (pH 7.9); gradual wavy boundary. (8 to 14 inches thick)
3Bkg4--51 to 53 inches; pale yellow (5Y 8/2) silt loam, light olive gray (5Y 6/2) moist; few fine faint light yellowish brown (2.5Y 6/7) dry redox concentrations; massive, very hard, firm, moderately sticky and moderately plastic; few very fine roots; few fine and medium tubular pores; strongly effervescent (25 percent calcium carbonate); moderately alkaline (pH 7.9); abrupt smooth boundary. (2 to 5 inches thick)
4BCkg--53 to 55 inches; gray (2.5Y 6/0) silt loam, bluish gray (5B 5/1) moist; many medium and large distinct olive yellow (2.5Y 6/6) dry mottles; massive; hard, firm, slightly sticky and moderately plastic; common very fine and fine tubular pores; slightly effervescent (1 percent calcium carbonate); moderately alkaline (pH 7.9); abrupt wavy boundary. (2 to 5 inches thick)
5Cg1--55 to 61 inches; gray (2.5Y 5/0) very fine sandy loam, dark bluish gray (5B 4/1) moist; few fine and medium faint olive yellow (2.5Y 6/6) dry redox concentrations; massive; hard, firm, slightly sticky and slightly plastic; common very fine and fine tubular pores; moderately alkaline (pH 8.0); abrupt wavy boundary. (4 to 8 inches thick)
6Cg2--61 to 72 inches; dark gray (2.5Y 4/0) extremely gravelly loamy sand, dark bluish gray (5B 4/1) moist; single grain; loose, very friable; 55 percent pebbles, 10 percent cobbles; slightly alkaline (pH7.8).
TYPE LOCATION: Blaine County, Idaho, about 2 miles south and 3/4 miles east of Gannett; 1,100 feet west and 40 feet north of the southeast corner of section 14, T 1 S., R. 19 E.
RANGE IN CHARACTERISTICS:
Mollic epipedon - In some pedons, the mollic epipedon may have color values greater than 5.5 dry and 3.5 moist, due to high concentrations of calcium carbonate present (greater than 40 percent).
Average annual soil temperature - 42 to 47 degrees F.
Depth to calcium carbonate nodules - 36 to 50 inches
Depth to water table - 2 to 4 feet from October to May
Ak horizon
Hue - 10YR or 2.5Y
Value - 5 or 6 dry and 3 through 5 moist
Chroma - 1 through 3 dry or moist
Sodium absorption ratio - 25 to 40
Reaction - moderately to strongly alkaline
Bk horizon
Hue - 10YR, 2.5Y or 5Y
Value - 6 or 7 dry and 3 through 6 moist
Chroma - 1 or 2 dry and 1 through 3 moist
Textures - L or SIL
Irregular shaped gravel sized calcium carbonate concretions - range
from 0 to 5 percent
Total clay - 10 to 18 percent
Carbonate clay - 6 to 11 percent
Sodium absorption ratio - 1 to 10
Reaction - moderately to strongly alkaline
2Bkg horizon
Value - 7 or 8 dry and 6 or 7 moist
Chroma - 1 or 2 dry and 2 or 3 moist
Textures - GR-SIL or SIL
Irregular shaped pebble sized calcium carbonate concretions - range
from 10 to 35 percent
Total clay - 30 to 38 percent
Carbonate clay - 25 to 30 percent
3Bkg, 4BCkg and 5Cg horizons
Hue - 5Y, 2.5Y or 5B
Value - 5 through 8 dry and 4 through 6 moist
Chroma - 0, 2 or 4 dry and 1 through 4 moist
Textures - FSL, VFSL, L, and SIL
Reaction - neutral to strongly alkaline
6Cg horizon
Hue - 5Y, 2.5Y, 5B, 10YR
Value - 4 or 5 dry or moist
Chroma - 0 or 2 dry and 1 through 3 moist
Textures - GRV-LS, GRV-S, and GRX-LS
Coarse fragments - range from 35 to 70 percent
Reaction - neutral to slightly alkaline
COMPETING SERIES: This is the similar Zunhall series. Zunhall soils have more than 18 percent clay in the control section.
GEOGRAPHIC SETTING: Picabo soils are on stream terraces and flood plains. Slopes range from 0 to 2 percent. Elevation ranges from 4,700 to 5,000 feet. The soil formed in alluvium from mixed sources. The average annual precipitation is 12 to 16 inches, most of which falls as snow and early spring rains. The average annual air temperature is about 40 to 45 degrees F. The frost free season is 70 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bruneel, Hapur, and Bickett soils. Bruneel soils are 20 to 40 inches to gravel and do not have calcium carbonate concretions. Hapur soils are poorly drained. Bickett soils are very poorly drained and are dominantly composed of organic matter. These soils occur on the same landscape.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; moderate permeability; the water table is at 2 to 4 feet from October to May.
USE AND VEGETATION: Mainly used for cropland and pastureland. Natural vegetation includes shrubby cinquefoil, wildrose, redtop, saltgrass, and sedges.
DISTRIBUTION AND EXTENT: The series is inextensive in south central Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Blaine County, Idaho, 1985.
REMARKS: Diagnostic horizons and features present in this series are:
Mollic epipedon - the zone from the surface of the soil to approximately 16 inches (Ak, ABk, and Bk1 horizons)
Calcic horizon - the zone from the soil surface to approximately 51 inches
Oxyaquic Calcixerolls feature - the soils to a depth of 1 meter are continuously saturated for more than 90 consecutive days