LOCATION SKIBO IDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, carbonatic Xeric Calcicryolls
TYPICAL PEDON: Skibo very stony loam--on a 26 percent slightly concave, southeast-facing slope at 7,150 feet elevation in rangeland. (Colors are for dry soil unless otherwise stated. When described on October 9, 1984 the soil was moist throughout.)
Oi--0 to 1 inch; slightly decomposed leaves and twigs. (0 to 1 inch thick)
A--1 to 5 inches; dark grayish brown (10YR 4/2) very stony loam, very dark brown (10YR 2/2) moist; weak very fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine and fine interstitial and tubular pores; 25 percent gravel, 35 percent cobbles, 5 percent stones; slightly alkaline (pH 7.6); clear wavy boundary. (2 to 15 inches thick)
Bk1--5 to 10 inches; brown (10YR 5/3) extremely cobbly loam, dark brown (10YR 3/3) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and few very fine roots; common very fine and fine interstitial and tubular pores; 25 percent gravel, 35 percent cobbles, 5 percent stones; lime coatings less than 1 mm thick on undersides and some sides of rock fragments; slightly effervescent; slightly alkaline (pH 7.8); gradual wavy boundary. (0 to 6 inches thick)
Bk2--10 to 20 inches; yellowish brown (10YR 5/4) extremely cobbly loam, brown (10YR 4/3) moist; moderate fine and medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few very fine and fine roots; common very fine and fine interstitial and tubular pores; 35 percent gravel, 25 percent cobbles, 15 percent stones; lime coatings 1 to 2 mm thick on all surfaces of rock fragments; violently effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (5 to 12 inches thick)
Bk3--20 to 27 inches; pale brown (10YR 6/3) extremely gravelly loam, brown (10YR 5/3) moist; moderate fine and medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few very fine and fine roots; common very fine and fine interstitial and tubular pores; 35 percent gravel, 25 percent cobbles, 10 percent stones; lime coatings 1 to 2 mm thick on all surfaces of rock fragments; violently effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (5 to 12 inches thick)
Bk4--27 to 35 inches; light gray (10YR 7/2) extremely gravelly loam, pale brown (10YR 6/3) moist; massive; slightly hard, firm, slightly sticky and slightly plastic; few very fine roots; common very fine and fine interstitial and tubular pores; 50 percent gravel; 20 percent cobbles, 10 percent stones; lime coatings 1 to 2 mm thick on all surfaces of rock fragments; common soft masses of secondary lime; violently effervescent; moderately alkaline (pH 8.2); gradual smooth boundary. (6 to 14 inches thick)
Bk5--35 to 61 inches; light gray (10YR 7/2) extremely gravelly fine sandy loam, brown (10YR 5/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; common very fine and fine interstitial and tubular pores; 60 percent gravel, 5 percent cobbles, 5 percent stones; lime coatings 1 to 2 mm thick on all surfaces of rock fragments; common visible soft masses of secondary lime; violently effervescent; moderately alkaline (pH 8.4).
TYPE LOCATION: Custer County, Idaho; approximately 1 mile southwest of Willow Creek Summit, about 1,500 feet south and 650 feet east from the northwest corner of section 9, T. 10 N., R. 21 E.
Latitude - 44 degrees, 12 minutes, 50 seconds North
Longitude - 113 degrees, 59 minutes, 17 seconds West
RANGE IN CHARACTERISTICS:
The soil moisture control section is dry for one-half to three-fourths of the time when the soil temperature is above 41 degrees F.; dry for 45 to 70 consecutive days.
Average annual soil temperature - 34 to 42 degrees F.
Average summer soil temperature - 46 to 55 degrees F. (without an O horizon)
Mollic epipedon thickness - 8 to 12 inches
Particle-size control section; percent total clay - 13 to 22 percent carbonate free clay
Rock fragments - 55 to 85 percent (greater than 5 percent stones)
Calcium carbonate equivalent - 40 to 80 percent
Depth to calcic horizon - 2 to 15 inches
A horizon
Value - 3 or 4 dry, 2 or 3 moist
Chroma - 1 through 3, dry or moist
Bk horizon
Value - 5 through 7 dry, 3 through 6 moist
Chroma - 1 through 4, dry or moist
Texture - CBX-L, GRX-L, GRX-FSL, GRV-L, CBX-SL
Rock fragments - 55 to 90 percent
Reaction - slightly alkaline or moderately alkaline
COMPETING SERIES: These are the Canyoung, Fritz, Gepton, Hanson, Hardhart, Pahreah, Skaggs, Zeale and Zeelnot series. Canyoung soils have a mean summer soil temperature of 54 to 59 degrees F. Fritz soils are dominated by gravel size coarse fragments throughout the profile. Gepton soils have a cambic horizon. Hanson soils have a udic moisture regime. Hardhart and Pahreah soils are 20 to 40 inches to a lithic contact. Skaggs soils are 20 to 40 inches to a paralithic contact. Zeale soils are dry for 100 to 125 consecutive days. Zeelnot soils lack an O horizon.
GEOGRAPHIC SETTING: Skibo soils are on mountains. These soils formed in colluvium from limestone. Slopes are 20 to 70 percent. Elevations are 6,600 to 9,000 feet. The climate is cold and moist in winter and spring, and cool and dry in the summer. The average annual precipitation is 16 to 20 inches; average annual temperature is 32 to 40 degrees F.; and the frost-free period is 10 to 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are Adek, Meegernot, Nitchly, and the competing Zeale soils on mountains. Adek soils have a mollic epipedon. Meegernot soils are not calcareous to the soil surface. Nitchly soils have an aridic soil moisture regime.
DRAINAGE AND PERMEABILITY: Well drained. Medium runoff; moderate permeability.
USE AND VEGETATION: Rangeland. Vegetation is mainly curlleaf mountain mahogany and bluebunch wheatgrass.
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:
Mollic epipedon - The zone from 1 to 9 inches
Calcic horizon - The zone from 5 to 61 inches
The soil is calcareous to the mineral soil surface after mixing the upper 7 inches of the mineral soil surface.
Xeric soil moisture regime.
Particle-size control section - The zone from 11 to 41 inches
All depths to diagnostic horizons and features are measured from the top of the first mineral horizon.