LOCATION HEATHCOAT ID+COEstablished Series
TAXONOMIC CLASS: Fine, smectitic Vertic Argicryolls
TYPICAL PEDON: Heathcoat gravelly silt loam--on an 8 percent north- by northeast-facing slope at 7,300 feet elevation in rangeland. (Colors are for dry soil unless otherwise stated. When described on July 21, 1981, the soil was dry to 18 inches and moist below this depth.)
A1--0 to 2 inches; very dark grayish brown (10YR 3/2) gravelly silt loam, very dark brown (10YR 2/2) moist; weak very fine, fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and few fine and medium roots; many very fine irregular pores; 15 percent gravel; slightly acid (pH 6.2); clear wavy boundary. (1 to 4 inches thick)
A2--2 to 6 inches; very dark grayish brown (10YR 3/2) loam, very dark brown (10YR 2/2) moist; moderate very fine, fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; many very fine and few fine, medium and coarse roots; common very fine irregular pores; many faint clay films lining pores and on faces of peds; 10 percent gravel; neutral (pH 6.7); clear wavy boundary. (2 to 7 inches thick)
Bt1--6 to 10 inches; dark grayish brown (10YR 4/2) clay loam, very dark grayish brown (10YR 3/2) moist; weak very fine and fine prismatic structure parting to moderate very fine, fine and medium subangular blocky; slightly hard, friable, moderately sticky and moderately plastic; common very fine and few fine, medium and coarse roots; common very fine irregular and few very fine tubular pores; many distinct clay films lining pores and on faces of peds; 10 percent gravel; neutral (pH 7.0); clear wavy boundary. (2 to 8 inches thick)
Bt2--10 to 13 inches; brown (10YR 5/3) clay, dark brown (10YR 4/3) moist; weak very fine and fine prismatic structure parting to moderate very fine, fine and medium subangular blocky; hard, friable, moderately sticky and moderately plastic; common very fine and few fine, medium and coarse roots; few very fine irregular and tubular pores; many distinct clay films lining pores and on faces of peds; 5 percent gravel; lime and silica coatings less than 1mm thick on undersides of coarse fragments; slightly effervescent; slightly alkaline (pH 7.6); clear wavy boundary. (2 to 5 inches thick)
Btk--13 to 17 inches; pale brown (10YR 6/3) clay, yellowish brown (10YR 5/4) moist; moderate very fine and fine prismatic structure parting to moderate fine and medium subangular blocky; hard, firm, moderately sticky and modeately plastic; common very fine and few fine roots; many very fine tubular pores; many distinct clay films lining pores and on faces of peds; 2 percent gravel; lime and silica coatings less than 1mm thick on undersides of coarse fragments; strongly effervescent; slightly alkaline (pH 7.7); gradual wavy boundary. (2 to 6 inches thick)
2Btkb1--17 to 37 inches; very pale brown (10YR 7/3) silty clay, light yellowish brown (10YR 6/4) moist; strong medium and coarse prismatic structure; hard, firm, moderately sticky and moderately plastic; common very fine and few fine roots; common very fine tubular pores; many distinct clay films lining pores and on faces of peds; 15 percent visible secondary lime on ped faces and in old root channels; violently effervescent; slightly alkaline (pH 7.8); gradual wavy boundary. (14 to 26 inches thick)
2Btkb2--37 to 47 inches; very pale brown (10YR 7/3) silty clay, pale brown (10YR 6/3) moist; strong medium and coarse prismatic structure; hard, firm, moderagely sticky moderately and plastic; few very fine roots; common very fine tubular pores; many prominent clay films lining pores and on faces of peds; strongly effervescent; slightly alkaline (pH 7.8); abrupt wavy boundary. (5 to 15 inches thick)
3Btkb3--47 to 60 inches; very pale brown (10YR 8/3) very gravelly clay loam, light yellowish brown (10YR 6/4) moist; massive; slightly hard, very friable, moderately sticky and moderately plastic; common very fine tubular and few very fine irregular pores; few faint clay films lining pores and on faces of peds; 30 percent gravel, 15 percent cobbles; lime and silica coatings less than 1mm thick on undersides of coarse fragments; violently effervescent; moderately alkaline (pH 7.9).
TYPE LOCATION: Lemhi County, Idaho; about 300 feet west and 1,700 feet south of the northeast corner of sec. 27, T. 13 N., R. 27 E.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 39 to 42 degrees F. Average summer soil temperature - 52 to 57 degrees F.
Mollic epipedon thickness - 7 to 15 inches
Depth to lime - 8 to 24 inches
Depth to calcic horizon - 10 to 30 inches
Control section - percent clay 35 to 50
Coarse fragments - 0 to 30 percent
A horizon
Value - 3 or 4 dry, 2 or 3 moist
Chroma - 1 or 2 dry or moist
Reaction - slightly acid to neutral
Bt horizons
Hue - 10YR or 7.5YR
Value - 4 through 7 dry, 3 through 6 moist
Chroma - 2 through 4 dry or moist
Texture - CL, C, SIC, SICL, SC, GR-SCL, GR-CL, GR-C
Reaction - neutral to slightly alkaline
Btkb horizon
Hue - 10YR to 5Y
Value - 6 through 8 dry, 5 through 7 moist
Chroma - 3 or 4 dry or moist
Texture - SIC, C, SCL, GRV-CL, CL, CBV-CL, CB-CL
Reaction - slightly alkaline or moderately alkaline
COMPETING SERIES: These are the Beaverdam, Blackhorse (T), Brinkert, Buckskin, Gothic, Heath, Jerry, Judy, Little Horn, Mayoworth, Owen Creek, Piltz, Sessions, Sneffels, Trout Creek, and Youman series. The Beaverdam, Jerry, and Sessions soils lack calcic horizons. Blackhorse soils are carbonatic below 12 inches. Brinkert and Gothic soils range from 40 to more than 60 inches to uniformly calcareous material. Buckskin soils are noncalcareous. Heath soils are not dry for 45 consecutive days in the 4 months that follow the summer solstice. Judy, Little Horn and Sneffels soils have a lithic contact at 20 to 40 inches. Mayoworth, Owen Creek, Piltz, and Trout Creek soils have a paralithic contact at depths of 20 to 40 inches or immediately below the solum if the solum is thicker than 40 inches. Youman soils have hues redder than 7.5YR.
GEOGRAPHIC SETTING: Heathcoat soils are on fan terraces, hills, mountains and plateaus and have slopes of 1 to 50 percent. Elevations range from 6,500 to 8,500 feet. The soils formed in uplifted lacustrine sediments, colluvium from shale, and alluvial deposits over glacial till. The climate is cold and moist in winter and spring, and cool and dry in summer. Average annual precpitation is 13 to 16 inches, and average annual temperature is 37 to 40 degrees F. The frost-free period is 30 to 75 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the proposed Brabas (T), Chamberlain (T), Escarlo (T), Goldhill (T), and Oxhead (T) soils. Brabas, Goldhill, and Oxhead soils are on hills and lack mollic epipedons. Chamberlain soils are on fan terraces and outwash fans and have loamy-skeletal control sections. Escarlo soils are on hills and lack argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; slow permeability.
USE AND VEGETATION: Rangeland. Vegetation is mainly mountain big sagebrush and Idaho fescue.
DISTRIBUTION AND EXTENT: East-central Idaho and northwestern Colorado. These soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Moffat County Area, Colorado, 1991.
REMARKS: Diagnostic features recognized in this pedon are:
Mollic epipedon - the zone from 0 to 10 inches (the A1, A2, and Bt1 horizons)
Argillic horizon - the zone from 6 to 17 inches (Bt1, Bt2, and Btk horizons)
Calcic horizon - the zone from 17 to 60 inches (2Btkb1, 2Btkb2, and 3Btkb3 horizons)
Vertic subgroup - linear extensibility is over 6 cm between 0 and 100 cm.
The particle-size control section is the zone from 6 to 26 inches or the upper 20 inches of the argillic (Bt1, Bt2, BtK, and part of the 2Btkb1 horizons)
This series has a xeric moisture regime but borders on aridic.