LOCATION DIMYAW MTEstablished Series
TAXONOMIC CLASS: Fine, smectitic, calcareous, frigid Typic Ustorthents
TYPICAL PEDON: Dimyaw silty clay - native grassland. (Colors are for dry soil unless otherwise noted.)
A11--0 to 1 inch; light brownish gray (2.5Y 6/2) silty clay, dark grayish brown (2.5Y 4/2) moist; strong fine granular structure; hard, firm, sticky, plastic; mildly alkaline (pH 7.8); clear boundary. (1 to 4 inches thick)
A12--1 to 8 inches; olive gray (5Y 5/2) silty clay, olive gray (5Y 4/2) moist; weak medium prismatic and fine blocky structure; very hard, firm, sticky, plastic; common fine roots and pores; mildly alkaline (pH 7.8); clear boundary. (4 to 8 inches thick)
C1ca--8 to 14 inches; pale olive (5Y 6/3) silty clay, olive (5Y 5/3) moist; weak thin platy structure; very hard, firm, sticky, plastic; common fine roots; calcareous, many threads and soft nodules of lime; moderately alkaline (pH 8.2); gradual boundary. (4 to 8 inches thick)
C2--14 to 60 inches; pale olive (5Y 6/3) silty clay, olive (5Y 5/3) moist; massive; very hard, firm, sticky, plastic; few fine roots and pores; few thin strata of hard siltstone; common threads of lime (pH 8.4).
TYPE LOCATION: Dawson County, Montana; about 2,100 feet west and 1,100 feet south of NE corner of sec. 23, T.16N., R.57E.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 43 degrees to 47 degrees F. The soils have hue of 2.5Y or 5Y, dry value of 5 or 7, moist value of 4 through 6, and chroma of 2 through 4. All horizons range from clay loam to silty clay with clay content ranging from 36 to 50 percent. Estimated cation exchange capacity ranges from 50 to 60 millequivalents per 100 grams of clay. Soft sedimentary beds underlie the C1ca horizon in some pedons but these beds do not restrict root distribution.
COMPETING SERIES: These are the Epsie, Kuro, Lambert, Lisam, Midway, and Wayden series. Epsie and Lisam soils have 50 to 60 percent clay and are usually dry. Kuro soils have paralithic contact with red shale at depths of about 15 inches and have hues ranging from 5YR through 10R. Lambert soils have less than 35 percent clay and have from 5 to 10 Percent fine and coarser sands. Midway soils are usually dry and have a mesic temperature regime. Wayden soils have paralithic contact at a depth of less than 20 inches.
GEOGRAPHIC SETTING: Dimyaw soils are on rolling to steep and broken sedimentary uplands. They formed in calcareous, clayey, soft to weakly consolidated sediments. Mean annual precipitation is 10 to 14 inches. Mean annual temperature is 40 degrees to 45 degrees F., mean January temperature is 10 degrees to 25 degrees F., and mean July temperature is 66 degrees to 72 degrees F. The frost-free season is 90 to 135 days.
PRINCIPAL ASSOCIATED SOILS: These are the Regent and Ringling soils and the competing Lambert soil. Regent soils have a mollic epipedon. Ringling soils have a fragmental control section.
DRAINAGE AND PERMEABILITY: Well drained and somewhat excessively drained; medium to rapid runoff; slow permeability.
USE AND VEGETATION: These soils are used mainly for range. Principal vegetation is western wheatgrass, bluebunch wheatgrass, green needlegrass, blue grama, and numerous forbs.
DISTRIBUTION AND EXTENT: Eastern and northern plains of Montana and in adjacent areas in North and South Dakota. The series is extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Dawson County, Montana, 1971.
REMARKS: The Dimyaw soils were formerly classified as Lithosols. They were originally included in the Midway series.
OSED scanned by SSQA. Last revised by state on 5/73.