LOCATION EDGAR MTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Haplocalcidic Haplustepts
TYPICAL PEDON: Edgar loam - grassland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 3 inches; pale brown (10YR 6/3) loam, dark brown (10YR 4/3) moist; moderate fine and medium platy structure; soft, very friable, nonsticky, nonplastic; many very fine roots; few fine tubular pores; many very fine interstitial pores; neutral; clear boundary. (2 to 4 inches thick)
B2--3 to 9 inches; brown (10YR 5/3) loam coated with dark grayish brown (10YR 4/2), dark brown (10YR 4/3) coated with very dark grayish brown (10YR 3/2) moist; moderate medium prismatic structure that separates to moderate medium blocks; hard, very friable, slightly sticky, slightly plastic; many very fine roots; many fine and very fine tubular pores; neutral; clear boundary. (6 to 10 inches thick)
B3--9 to 12 inches; light olive brown (2.5Y 5/4) loam, olive brown (2.5Y 4/4) moist; weak medium prismatic structure; hard, very friable, slightly sticky, slightly plastic; many very fine roots; many very fine and fine tubular pores; strong effervescence; moderately alkaline (pH 8.2); clear boundary. (2 to 8 inches thick)
C1ca--12 to 24 inches; pale yellow (2.5Y 7/3) loam, light olive brown (2.5Y 5/3) moist; massive; hard, very friable, slightly sticky, slightly plastic; common very fine roots; common very fine and fine tubular pores; violent effervescence with many soft, white accumulations of lime; moderately alkaline (pH 8.4); gradual boundary. (10 to 20 inches thick)
C2--24 to 60 inches; pale yellow (5Y 7/3) light clay loam, olive (5Y 5/4) moist; massive; hard, very friable, slightly sticky, slightly plastic; few very fine roots; common very fine and fine tubular pores; violent effervescence; moderately alkaline (pH 8.4).
TYPE LOCATION: Treasure County, Montana; near SE corner of NW1/4 of SW1/4 of sec. 7, T.6N., R.38E.
RANGE IN CHARACTERISTICS: The Edgar soils are usually dry between depths of 4 and 12 inches but are not dry in all parts above 12 inches for more than half the time that soil temperature at 20 inches is more than 41 degrees F. The mean annual soil temperature is 48 degrees to 50 degrees F. The solum is 11 to 15 inches thick. The soil between depths of 10 and 40 inches is loam or light clay loam with 18 to 30 percent clay and 16 to 30 percent percent fine and coarser sands. The soil is neutral to mildly alkaline in the noncalcareous part of the solum and moderately to strongly alkaline in the C horizons. An Ap horizon ranging from 4 to 7 inches thick in cultivated fields has hue of 2.5Y or 10YR, value of 5 or 6 dry and 4 moist, and chroma of 2 or 3. The B2 horizon has moderate or strong prismatic structure, has hue of 2.5Y or 10YR and value of 5 or 6 dry and chroma of 2 through 4. The Cca horizon has hue of 5Y or 2.5Y and dry value of 7 or 8. It contains about 20 to 30 percent CaC03 equivalent.
COMPETING SERIES: These are the Harvey, La Fonda, McRae, Remmit, Thedalund and Zigweid series. Harvey soils lack cambic horizons. La Fonda soils have hue of 5YR. McRae soils lack calcic horizons. Remmit soils have less than 18 percent clay in their 10- to 40-inch control section. Thedalund soils lack cambic and calcic horizons. Zigweid soils have sola 15 to 30 inches thick.
GEOGRAPHIC SETTING: Edgar soils are on nearly level to sloping and undulating alluvial fans, river and stream terraces and upland plains. They formed in unconsolidated calcareous loam materials of mixed mineralogy. Mean annual temperature is 45 degrees to 50 degrees F. and the average annual precipitation is 8 to 14 inches.
PRINCIPAL ASSOCIATED SOILS: These are the Hesper, Keiser, Midway, Nihill, Toluca and Wanetta soils. Hesper, Keiser, Toluca and Wanetta soils have argillic horizons. Midway and Nihill soils lack cambic and calcic horizons and Midway soils rest on clay loam shale bedrock at shallow depths.
DRAINAGE AND PERMEABILITY: Well-drained; slow to medium runoff; moderately permeable.
USE AND VEGETATION: Used for irrigated and nonirrigated cropland and for range. Native grasses are western wheatgrass, prairie junegrass, needle-and-thread and blue grama.
DISTRIBUTION AND EXTENT: Edgar soils occur in southeastern Montana where they are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Treasure County, Montana, 1961.
REMARKS: The Edgar soils were formerly classified as Brown soils.
OSED scanned by SSQA. Last revised by state on 9/71.