LOCATION LACROL IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Vertic Palexerolls
TYPICAL PEDON: Lacrol silt loam--on a 25 percent northeast facing slope in rangeland at 5,800 feet elevation. (Colors are for dry soil unless otherwise stated. When described, the soil was dry to a depth of 60 inches.)
A--0 to 2 inches; brown (10YR 4/3) silt loam, very dark brown (10YR 2/2) moist; weak very fine and fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and few fine roots; many very fine irregular pores; 5 percent gravel and 2 percent cobbles; neutral (pH 7.0); clear wavy boundary. ((2 to 8 inches thick)
EB--2 to 7 inches; brown (10YR 5/3) clay loam, very dark grayish brown (10YR 3/2) moist; weak very fine and fine subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; common very fine and few fine and medium roots; common very fine irregular pores; 10 percent gravel; neutral (pH 7.0); abrupt wavy boundary. (5 to 9 inches thick)
Bt--7 to 15 inches; brown (7.5YR 4/3) clay, dark brown (7.5YR 3/3) moist; moderate fine and medium prismatic structure parting to strong fine, medium and coarse subangular blocky; extremely hard, extremely firm, very sticky, and very plastic; few very fine and fine roots; few very fine irregular pores; many distinct clay films in pores and on faces of peds; 2 percent gravel; slightly alkaline (pH 7.4); clear wavy boundary. (8 to 15 inches thick)
Btk1--15 to 25 inches; brown (7.5YR 5/4) clay, dark brown (7.5YR 3/4) moist; strong fine, medium, and coarse subangular blocky structure; very hard, very firm, very sticky and very plastic; few very fine and fine roots; few very fine irregular pores; many distinct clay films in pores and on faces of peds; slightly effervescent; moderately alkaline (pH 8.0); gradual wavy boundary. (10 to 16 inches thick)
Btk2--25 to 31 inches; brown (7.5YR 5/4) clay, dark brown (7.5YR 4/4) moist; strong fine, medium, and coarse subangular blocky structure; hard, firm, very sticky and very plastic; few very fine and fine roots; few very fine irregular pores; many prominent clay films in pores and on faces of peds; slightly effervescent; moderately alkaline (pH 8.4); gradual wavy boundary. (6 to 15 inches thick)
Btk3--31 to 60 inches; light brown (7.5YR 6/4) clay, brown (7.5YR 5/4) moist; weak fine prismatic structure parting to strong fine, medium, and coarse subangular blocky; hard, firm, very sticky, and plastic; few very fine irregular pores; many faint clay films in pores and on faces of peds; slightly effervescent; strongly alkaline (pH 8.6).
TYPE LOCATION: Lemhi County, Idaho; about 2 miles SW of Tendoy, Idaho; about 1,800 feet north and 1,400 feet west of the southeast corner of section 25, T. 19 N., R. 23 E.
Latitude - 44 degrees, 57 minutes, 02 seconds North
Longitude - 113 degrees, 40 minutes, 23 seconds West
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 41 to 45 degrees F.
Mollic epipedon thickness - 7 to 16 inches
Depth to perched water table - 6 to 14 inches in March to May
Total linear extensibility in the upper 40 inches - 6.0 to 8.0 cm
Control section; percent clay - 40 to 60
Rock fragments - 0 to 30 percent
Depth to secondary carbonates - 15 to 60 inches or more
Moisture regime - xeric
A horizon Value - 4 or 5 dry, 2 or 3 moist
Chroma - 1 through 3 dry or moist
EB horizon
Hue - 7.5YR or 10YR Value - 5 or 6 dry, 3 through 5 moist Chroma - 2 through 4 dry or moist
Texture - L, CL, GR-CL, GR-L
Rock fragments - 0-20 percent
Bt horizon
Hue - 2.5YR, 7.5YR, or 10YR
Value - 4 through 7 dry, 3 through 5 moist
Chroma - 2 through 6 dry or moist
Texture - C, GR-C, SIC
Btk horizon
Hue - 7.5YR or 10YR
Value - 5 through 7 dry, 3 through 6 moist
Chroma - 3 through 6 dry or moist
Texture - C, GR-C, CB-C, CL, GR-CL, SIC
Rock fragments - 0 to 20 percent
COMPETING SERIES: These are the Booth, Campcreek, Carryback, Crowcamp, Tippett and Zumwalt series. Booth, Carryback and Zumwalt soils are moderately deep. Campcreek soils are on terrace escarpments and are well drained. Crowcamp soils have an aridic moisture regime, are somewhat poorly drained and have a mollic epipedon 20 to 30 inches thick. Tippett soils have an A horizon 8 to 12 inches thick that has vitrandic properties.
GEOGRAPHIC SETTING: Lacrol soils are on foothills and mountain sideslopes and have slopes of 15 to 35 percent. The soils formed in mixed lacustrine sediments. Elevations are 4,500 to 6,800 feet. The climate is cold and moist in winter and spring and dry in summer. Average annual precipitation is 13 to 16 inches. Average annual temperature is 39 to 44 degrees F. Frost-free period is 50 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cronks, Friedman, Klug, Millhi, Povey, Shenon, and Venum soils. Cronks and Venum soils are on foothills and mountains, and have clayey-skeletal control sections. Venum soils have ochric epipedons. Friedman soils are on mountains and have clayey-skeletal control sections and have overthickened mollic epipedons. Klug and Povey soils are on mountains and have loamy-skeletal control sections. Povey soils have overthickened mollic epipedons. Millhi soils are on foothills and have ochric epipedons. Shenon soils are on fan terraces and have fine-loamy control sections.
DRAINAGE AND PERMEABILITY: Moderately well drained; medium runoff; very slow permeability.
USE AND VEGETATION: Rangeland. Vegetation is mainly threetip sagebrush and Idaho fescue.
DISTRIBUTION AND EXTENT: East-central Idaho. These soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Lemhi County, Idaho, 1999.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 15 inches (A, EB, and Bt horizons)
Argillic horizon - The zone from 7 to 15 inches (Bt, Btk1, Btk2, and Btk3 horizons)
Particle-size control section - The zone from 7 to 27 inches (Bt1, Btk1, and part of Btk2 horizons)