LOCATION CRONKS IDEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Calciargidic Argixerolls
TYPICAL PEDON: Cronks very cobbly loam on a 16 percent east-facing slope at an elevation of 5,200 feet on rangeland. (Colors are for dry soil unless otherwise noted. When described on November 7, 1979, the soil was dry throughout.)
A--0 to 10 inches; brown (10YR 5/3) very cobbly loam, very dark grayish brown (10YR 3/2) moist; weak thin platy structure parting to weak fine granular; slightly hard, very friable, slightly sticky and nonplastic; many very fine roots; many very fine and fine irregular pores; 15 percent gravel, 25 percent cobbles; slightly acid (pH 6.2); clear wavy boundary. (3 to 12 inches thick)
Bt1--10 to 14 inches; brown (10YR 5/3) very cobbly clay, dark yellowish brown (10YR 4/4) moist; strong fine and medium angular blocky structure; hard, firm, moderately sticky and moderately plastic; many very fine roots; many very fine tubular pores; many distinct thick clay films lining pores and on faces of peds; 15 percent gravel; 25 percent cobbles; neutral (pH 6.6); clear wavy boundary. (3 to 5 inches thick)
Bt2--14 to 36 inches; brown (10YR 5/3) very cobbly clay, olive brown (2.5Y 4/3) moist; strong very fine and medium angular blocky structure; very hard, very firm, very sticky and very plastic; common very fine roots; many very fine tubular pores; many distinct clay films lining pores and on faces of peds; 15 percent gravel; 25 percent cobbles; neutral (pH 7.1); clear wavy boundary. (8 to 24 inches thick)
Bk--36 to 55 inches; pale brown (10YR 6/3) very cobbly silt loam, grayish brown (2.5Y 5/2) moist; moderate very fine angular blocky structure; slightly hard, very friable, slightly sticky, and slightly plastic; few very fine roots; many very fine tubular pores; 15 percent gravel; 30 percent cobbles; strongly effervescent; common fine and medium generally rounded and irregular shaped carbonate filaments or threads and in soft masses; slightly alkaline (pH 7.7); clear wavy boundary. (10 to 22 inches thick)
C--55 to 70 inches; pale brown (10YR 6/3) very cobbly clay loam, light olive brown (2.5Y 5/3) moist; massive; slightly hard, very friable, moderately sticky and moderately plastic; few very fine roots; many very fine and fine tubular pores; 15 percent gravel; 30 percent cobbles; slightly effervescent; moderately alkaline (pH 8.1).
TYPE LOCATION: Lemhi County, Idaho; about 1,800 feet west and 1,800 feet south from the northeast corner, sec. 28, T. 19 N., R. 21 E.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 39 to 45 degrees F.
Mollic thickness - 8 to 13 inches
Control section; Percent clay - 40 to 50
Rock fragments - 35 to 60
Depth to secondary lime - 14 to 36 inches
A horizon
Value - 3 to 5 dry, 2 or 3 moist
Chroma - 2 or 3, dry or moist
Bt horizon
Hue - 2.5Y, 7.5YR, or 10YR
Value - 5 or 6 dry, 3 to 5 moist
Chroma - 2 through 4, dry or moist
Texture - CBV-C, GRV-CL, GRV-C, CBV-CL
Bk and C horizons
Hue - 2.5Y, 7.5YR, or 10YR
Value - 5 to 7 dry, 4 to 6 moist
Chroma - 2 to 4, dry or moist
Texture - CBV-SIL, CBV-CL, CBV-L, GRX-L
Rock fragments - 35 to 60 percent
COMPETING SERIES: These are the Carstump and Golsum soils. Carstump and Golsum soils are moderately deep.
GEOGRAPHIC SETTING: Cronks soils are on foothills and mountains and have slopes of 6 to 60 percent. Elevations are 4,500 to 7,500 feet. The soils formed in mixed slope alluvium and colluvium derived dominantly from quartzite and andesite. The climate is cold and moist in winter and spring and dry in summer. Average annual precipitation is 11 to 13 inches. Average summer air temperature is 60 to 66 degrees F. Average annual air temperature is 37 to 44 degrees F. Frost-free period is 60 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Custco, Dacont, Dawtonia, Frailton, and Venum soils on mountains and foothills. Dacont, Dawtonia, and Custco have loamy-skeletal argillic horizons. Frailton soils are less than 20 inches to a paralithic contact. Venum soils have an ochric epipedon.
DRAINAGE AND PERMEABILITY: Well drained; medium to very rapid runoff; permeability is slow.
USE AND VEGETATION: Rangeland. Vegetation is mainly Wyoming big sagebrush and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: East-central Idaho. These soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Lemhi County, Idaho, 1999.
REMARKS: Diagnostic horizons and features recognized in the pedon are:
Mollic epipedon - The zone from the soil surface to a depth of 10 inches (A horizon)
Argillic horizon - The zone from 10 to 36 inches (Bt1 and Bt2 horizons)
Calcic horizon - The zone from 36 to 55 inches (Bk horizon)
Particle-size control section - The zone from 10 to 30 inches (Bt1 and part of the Bt2 horizons)