LOCATION GRADCO IDEstablished Series
TAXONOMIC CLASS: Ashy-skeletal, glassy, frigid Vitrixerandic Haplocalcids
TYPICAL PEDON: Gradco channery fine sandy loam--on a 16 percent north-facing slope at 6,400 feet elevation in rangeland. (Colors are for dry soil unless otherwise stated. When described on October 27, 1983, the soil was dry to 2 inches and moist to 24 inches.)
A--0 to 2 inches; light yellowish brown (10YR 6/4) channery fine sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine and few fine roots; many very fine irregular pores; 25 percent channers, 5 percent flagstones; slightly alkaline (pH 7.5); clear wavy boundary. (2 to 4 inches thick)
Bk--2 to 7 inches; light yellowish brown (10YR 6/4) very flaggy fine sandy loam, yellowish brown (10YR 5/4) moist; weak fine and medium subangular blocky structure parting to weak fine granular; soft, very friable, slightly sticky and slightly plastic; many very fine, common fine and few medium roots; common very fine and fine irregular and tubular pores; 25 percent channers, 30 percent flagstones; common lime coatings less than 1 mm thick on undersides and some sides of rock fragments; slightly effervescent; slightly alkaline (pH 7.6); clear wavy boundary. (3 to 6 inches thick)
Bkq1--7 to 14 inches; light yellowish brown (10YR 6/4) extremely flaggy fine sandy loam, yellowish brown (10YR 5/4) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine and few medium and coarse roots; common very fine and fine irregular and tubular pores; 20 percent channers, 45 percent flagstones; lime and silica coatings 1 to 2 mm thick on undersides and some sides of rock fragments; many visible soft masses of secondary lime, 15 percent calcium carbonate; strongly effervescent; strongly alkaline (pH 8.8); gradual wavy boundary. (3 to 8 inches thick)
Bkq2--14 to 24 inches; brownish yellow (10YR 6/6) extremely flaggy loam, yellowish brown (10YR 5/4) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and few fine and medium roots; few very fine irregular pores; 30 percent channers, 45 percent flagstones; lime and silica coatings 1 to 3 mm thick on undersides and some sides of rock fragments; many visible soft masses of secondary lime, 10 percent calcium carbonate; strongly effervescent; strongly alkaline (pH 8.7); abrupt wavy boundary. (5 to 12 inches thick).
Bky--24 to 33 inches; light yellowish brown (10YR 6/4) extremely flaggy loam, dark yellowish brown (10YR 4/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; few very fine irregular pores; 5 percent channers, 80 percent flagstones; thin coatings of segregated gypsum on 2 percent of rock fragments; minor pockets of sandy loam texture, 13 percent calcium carbonate; strongly effervescent; moderately alkaline (pH 8.3); abrupt wavy boundary. (7 to 12 inches thick)
Cr--33 inches; fractured, platy tuff; dead root mats on top of flagstones.
TYPE LOCATION: Custer County, Idaho; approximately 2 miles south of Grand View Canyon and 1/2 mile west of Highway 93, about 2,000 feet south and 2,400 feet east from the northwest corner of section 35, T. 12 N., R. 20 E. Latitude - 44 degrees, 19 minutes, 43 seconds North; Longitude - 114 degrees, 04 minutes, 11 seconds West.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 41 to 45 degrees F.
Control section; percent clay - 12 to 18
Rock fragments - 40 to 85 percent
Depth to calcic horizon - 5 to 15 inches
Depth to paralithic contact - 20 to 40 inches
Volcanic glass content - 30 to 50 percent
A horizon
Hue - 2.5Y or 10YR
Value - 3 or 4 moist
Chroma - 2 through 4 dry and 3 or 4 moist
Bk, Bkq, and Bky horizons
Hue - 10YR, 7.5YR, or 2.5Y
Value - 3 through 5 moist
Chroma - 3 through 6 dry, 3 or 4 moist
Texture - FLX-L, CBV-L, GRV-L, FLV-FSL, FLX-FSL
Rock fragments - 40 to 85 percent
Reaction - Slightly to strongly alkaline
Calcium carbonate equivalent - 10 to 20 percent
Gypsum content - 0 to 5 percent
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Gradco soils are on foothills, mountains, and ridges. These soils formed in residuum and colluvium from tuff. Slopes are 15 to 60 percent. Elevations are from 5,000 to 7,000 feet. The climate is cold and moist in winter and dry in summer. The average annual precipitation is 7 to 11 inches; average annual temperature is 39 to 43 degrees F.; and the frost-free period is 60 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dacont, Dawtonia, Farvant, Frailton, and Sactus soils. Dacont soils are on foothills and mountains and have a mollic epipedon and an argillic horizon. Dawtonia soils are on foothills and mountains and have an argillic horizon. Farvant soils are on foothills and ridges and are shallow to tuff. Frailton soils are on foothills and mountains and are shallow to tuff. Sactus soils are on ridges and summits and are very shallow to hard bedrock.
DRAINAGE AND PERMEABILITY: Well drained. Medium to rapid runoff; moderate permeability.
USE AND VEGETATION: Rangeland. Vegetation is mainly Wyoming big sagebrush, bluebunch wheatgrass, and common winterfat.
DISTRIBUTION AND EXTENT: East-central Idaho. These soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Custer County, Idaho, 1999.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon the zone from 0 to 7 inches (A and Bk horizons)
Calcic horizon - The zone from 7 to 14 inches
Particle-size control section - The zone from 10 to 33 inches (part of the Bkq1, the Bkq2, and the Bky horizons)