LOCATION LAGNAF UTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Pachic Argixerolls
TYPICAL PEDON: Lagnaf gravelly loam - range. (Colors are for air dry soil unless otherwise noted.)
A1--0 to 6 inches; dark grayish brown (10YR 4/2) gravelly loam, very dark brown (10YR /2) moist; moderate very fine subangular blocky structure; soft, friable, slightly sticky and slightly plastic; few medium, coarse and fine and common very fine roots; few medium, common fine, and many very fine random tubular pores; 5 percent cobbles, 25 percent gravel; neutral (pH 7.3); clear smooth boundary. (4 to 7 inches thick)
A2--6 to 14 inches; dark brown (7.5YR 4/2) gravelly loam, very dark brown (7.5YR 2/2) moist; moderate fine and very fine subangular blocky structure; slightly hard, firm, sticky and plastic; few medium and fine and common very fine roots; few medium, common fine, and many very fine random tubular pores; 5 percent cobbles and 25 percent gravel; neutral (pH 7.3); gradual smooth boundary. (2 to 8 inches thick)
BAt--14 to 22 inches; brown (7.5YR 4/3) gravelly clay loam, dark brown (7.5YR 3/2) moist; moderate medium subangular blocky structure parting to moderate fine and very fine subangular blocky; hard, firm, sticky and plastic; few medium, fine and very fine roots; few medium, common fine and many very fine random tubular pores; 5 percent cobbles and 25 percent gravel; neutral (pH 7.3) clear wavy boundary. (6 to 8 inches thick)
Bt1--22 to 31 inches; brown (7.5YR 5/3) gravelly clay loam, dark brown (7.5YR 3/2) moist; moderate medium subangular blocky structure parting to strong fine and very fine subangular blocky; hard, firm, sticky and plastic; few medium, fine and very fine roots; few medium, common fine and very fine random tubular pores; common moderately thick clay films on faces of peds; 5 percent cobbles, and 25 percent gravel; neutral (pH 7.2); clear smooth boundary. (5 to 18 inches thick)
Bt2--31 to 39 inches; brown (7.5YR 5/3) very gravelly clay loam, dark brown (7.5YR 3/3) moist; moderate medium subangular blocky structure parting to moderate fine and very fine subangular blocky; very hard, firm, sticky and plastic; few medium, fine and very fine roots; few medium, common fine and very fine random tubular pores; common moderately thick clay films on faces of peds; 10 percent cobbles and 30 percent gravel; neutral (pH 7.2); gradual wavy boundary. (6 to 12 inches thick)
BC--39 to 47 inches; brown (7.5YR 5/3) very gravelly clay loam, dark brown (7.5YR 3/3) moist; moderate fine and very fine subangular blocky structure; very hard, firm, sticky and plastic; few medium, fine, and very fine roots; few fine and common very fine random tubular pores; 10 percent cobbles and 25 percent gravel; slightly alkaline (pH 7.4); gradual wavy boundary. (8 to 10 inches thick)
C--47 to 63 inches; brown (7.5YR 5/3) very stony sandy loam, dark brown (7.5YR 3/2) moist; massive; loose, very friable, nonsticky, and nonplastic; few medium, fine and very fine roots; few fine and common very fine random tubular pores; 10 percent stones, 10 percent cobbles and 25 percent gravel; slightly alkaline (pH 7.4).
TYPE LOCATION: Iron County, Utah; one mile southwest of Chalk Hollow Pond in the Black Mountains; southwest quarter of section 7, T. 31 S., R. 8 W.
RANGE IN CHARACTERISTICS: The mollic epipedon is 35 to 50 inches thick or more. The solum thickness ranges from 38 to 50 inches. The depth to bedrock is more than 60 inches. Rock fragments range from 15 to 25 percent in the A horizon; 20 to 35 percent within the upper twenty inches of the Bt horizon and 25 to 40 in the lower part of the Bt horizon; and 25 to 50 percent in the C horizon. The mean annual soil temperature ranges from 45 to 47 degrees F. The mean summer soil temperature is 59 to 64 degrees F. The soil moisture regime is xeric bordering on aridic.
The A horizon has hue of 10YR or 7.5YR and value of 2 or 3 moist. This horizon is neutral or slightly alkaline and ranges from 6 to 14 inches thick.
The BAt and Bt1 horizons have hue of 10YR or 7.5YR, value of 2 or 3 moist, and chroma of 2 or 3 dry. It is gravelly loam or gravelly clay loam. This horizon is neutral or slightly alkaline.
The Bt2 horizon has hue of 10YR or 7.5YR, value of 4 through 6 dry, 2 through 4 moist, and chroma of 2 through 4 dry. It is dominantly gravelly sandy clay loam or gravelly clay loam, but is very gravelly clay loam in the lower part in some pedons. This horizon is neutral or slightly alkaline and ranges from 12 to 30 inches thick.
The BC and C horizons have hue of 10YR or 7.5YR, value of 5 or 6 dry, 3 or 4 moist and chroma of 2 through 4. It is very gravelly loam, very gravelly sandy loam, very gravelly clay loam, very stony sandy loam or very gravelly sandy clay loam. This horizon is neutral or slightly alkaline.
COMPETING SERIES: These are the Bly (OR), Carey Lake (ID), Dunford (UT), Hades (UT), Hurryback (ID), Krueger T(UT), Mahogan (CA), Marotz (ID), Moffspring T(ID), Nagle (OR), Sag (OR), Strom (ID) and Tusk (NV) series. Bly soils are influenced to some extent by ash, and reaction is usually slightly acid in the Bt horizon and not slightly alkaline in any part. Carey Lake soils have less than 10 percent rock fragments in the particle size control section and also contain relict mottles from 42 to 72 inches that were evidence of a high water table before a permanent change in drainage. Dunford are 20 to 40 inches deep to fractured andesite bedrock. Hades and Krueger soils have less than 20 percent rock fragments within the particle size control section. Hurryback soils contain less than 20 percent rock fragments in the upper 20 inches of the Bt horizon. Mahogan soils are 30 to 40 deep to hard extrusive igneous bedrock. Marotz soils are formed in glacial drift influenced by loess and have buried argillic horizons. Moffspring soils are moderately well drained and have a seasonal high water table at 3 to 6 feet from April to June. Nagle soils are calcareous at depths of 17 to 22 inches. Sag soils are 40 to 60 inches deep to slightly weathered fractured basalt bedrock. Strom soils are somewhat poorly drained and have a water table at 24 inches in the spring and recedes to below 50 inches in late summer and autumn. Tusk soils have mollic epipedons of less than 35 inches.
GEOGRAPHIC SETTING: These soils occur on rolling mountain slopes and old dissected alluvial fans at elevations of 7,200 to 8,400 feet. Slopes range from 15 to 40 percent. These soils formed in residuum and alluvium from basic and intermediate igneous rocks. The mean annual air temperature is 43 to 45 degrees F., and the frost free period is 70 to 100 days. The mean summer temperature is 60 to 65 degrees F. The average annual precipitation is 14 to 16 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bamos, Kinghorn, Pernty, Red Butte, and Tiki soils. Kinghorn, Pernty, Red Butte and Tiki soils have more than 35 percent rock fragments in the control section. Bamos, Kinghorn, Red Butte, and Tiki soils have a mesic temperature regime. Kinghorn and Tiki soils lack a mollic epipedon. Pernty soils are less than 20 inches deep to bedrock. Bamos and Red Butte soils have an aridic moisture regime and have layers of carbonate accumulation.
DRAINAGE AND PERMEABILITY: Well drained; moderate runoff; moderately slow permeability.
USE AND VEGETATION: Used mainly for rangeland, wildlife habitat and recreation. Vegetation is dominantly big sagebrush, bitterbrush, bluebunch wheatgrass and blue grama.
DISTRIBUTION AND EXTENT: Southern Utah. MLRA 47B. This soil is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Iron County, Utah; Iron-Washington Area, Utah 1997. MLRA 47B
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Pachic feature - a mollic epipedon that is deeper than 20 inches.
Argillic horizon - the zone from 14 to 39 inches.
Keys to Soil Taxonomy: Classified according to the Eighth Edition, 1998.
ADDITIONAL DATA: NSSL sample S74UT-021-006.