LOCATION COALKILN IDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, carbonatic Pachic Calcicryolls
TYPICAL PEDON: Coalkiln stony loam--rangeland. (Colors are for air-dry soil unless otherwise noted.)
Oi--0 to 1 inch; undecomposed leaves, needles and twigs. (1/2 to 1 inch thick)
Oe--1 to 3 inches; slightly decomposed organic material. (1/2 to 2 inches thick)
A1--3 to 7 inches; dark grayish brown (10YR 4/2) stony loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and slightly plastic; few very fine and medium and many fine roots; common very fine irregular pores; 10 percent gravel, 3 percent cobbles, and 2 percent stones; slightly alkaline (pH 7.4), clear smooth boundary. (2 to 10 inches thick)
A2--7 to 20 inches; grayish brown (10YR 5/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and many coarse roots; many very fine tubular pores; slightly effervescent; 10 percent gravel and 5 percent cobbles; slightly alkaline (pH 7.5); clear irregular boundary. (13 to 20 inches thick)
Bk1--20 to 27 inches; brown (10YR 5/3) very gravelly loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many medium and common coarse roots; many very fine irregular pores; violently effervescent (50 percent calcium carbonate equivalent); common distinct calcium carbonate coatings on underside of rock fragments; 30 percent gravel and 10 percent cobbles; slightly alkaline (pH 7.5); gradual wavy boundary. (5 to 15 inches thick)
Bk2--27 to 40 inches; pale brown (10YR 6/3) very gravelly loam, brown (10YR 4/3) moist; weak, fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many medium and common coarse roots; many very fine irregular pores; violently effervescent (50 percent calcium carbonate equivalent); 30 percent gravel and 15 percent cobbles; slightly alkaline (pH 7.6); clear wavy boundary. (8 to 15 inches thick)
Bk3--40 to 63 inches; light yellowish brown (10YR 6/4) extremely gravelly loam, dark yellowish brown (10YR 4/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; common fine roots; few very fine tubular pores; violently effervescent (55 percent calcium carbonate equivalent); 40 percent gravel and 25 percent cobbles; slightly alkaline (pH 7.8).
TYPE LOCATION: Custer County, Idaho; about 21 miles east of Clayton, Idaho; about 2,000 feet south and 1,500 feet west of the northeast corner of sec. 4, T. 10 N., R. 21 E. Latitude - 44 degrees, 13 minutes, 36 seconds North; Longitude - 113 degrees, 58 minutes, 31 seconds West.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 38 to 42 degrees F.
Average summer soil temperature - 43 to 47 degrees F.
Thickness of the mollic epipedon - 16 to 30 inches
Depth to calcic horizon - 16 to 30 inches
Soil moisture regime - udic
Particle-size control section:
Clay content - averages 18 to 24 percent
Rock fragment content - averages 35 to 70 percent
Calcium carbonate equivalent - 40 to 50 percent
A horizons:
Value - 3 through 5 dry and 2 or 3 moist
Chroma - 2 or 3 dry or moist
Reaction - neutral or slightly alkaline
Rock fragments - 15 to 35 percent
Calcium carbonate equivalent - averages 0 to 40 percent
Bk horizons:
Value - 5 to 7 dry and 3 or 4 moist
Chroma - 3 or 4 dry or moist
Texture - GRV-L, GRX-L
Rock fragments - 35 to 85 percent
Calcium carbonate equivalent - 35 to 55 percent
COMPETING SERIES: These are the Hardol (NV) and Meegero (ID) series. Hardol soils have a depth to the calcic horizon of 30 to 40 inches lack an O horizon and are xeric. Meegero soils have an average summer soil temperature of 47 to 50 degrees F and lack an O horizon and are xeric.
GEOGRAPHIC SETTING: Coalkiln soils are on mountainsides at elevations of 7,000 to 9,000 feet. They are typically on northern exposures and have slopes of 25 to 70 percent. These soils formed in colluvium and slope alluvium from limestone. Average annual precipitation is 20 to 26 inches and average annual air temperature ranges from 36 to 40 degrees F. The frost-free season is about 20 to 50 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Skibo and Zeelnot series. Skibo soils are on convex south-facing slopes. Zeelnot soils are on ridges and mountains.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.
USE AND VEGETATION: These soils are used for woodland, grazable woodland, and wildlife habitat. Potential natural vegetation is an overstory of Douglas fir and an understory dominated by pine reedgrass.
DISTRIBUTION AND EXTENT: Central Idaho. This series is 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 3 to 27 inches (A1, A2, Bk1 horizons)
Pachic feature - a mollic epipedon thicker than 16 inches.
Calcic horizon - the zone from 20 to 63 inches (Bk1, Bk2, Bk3 horizons)
The soil is calcareous to the mineral soil surface after mixing the upper 7 inches of the mineral soil surface.
Particle-size control section - the zone from 13 to 43 inches (part of the A2 horizon, the Bk1, Bk2, and part of the Bk3 horizons)
In the past and presently these soils were considered udic but they may be xeric; need more review.
All depths to diagnostic horizons and features are measured from the top of the first mineral horizon.