LOCATION TIMBERG MTEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, frigid Typic Haplustolls
TYPICAL PEDON: Timberg silty clay loam, cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 7 inches; dark reddish gray (5YR 4/2) silty clay loam, dark reddish brown (5YR 3/2) moist; strong fine granular structure; hard, friable, moderately sticky and moderately plastic; common fine and very fine roots; slightly alkaline (pH 7.6); abrupt wavy boundary. (7 to 10 inches thick)
Bw--7 to 12 inches; weak red (2.5YR 5/2) silty clay loam, reddish brown (2.5YR 4/4) moist; strong fine subangular blocky structure, very hard, friable, moderately sticky and moderately plastic; common fine and very fine roots; many fine and very fine pores; moderately effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (4 to 8 inches thick)
Bk--12 to 28 inches; weak red (10R 5/2) silty clay, dusky red (10R 3/3) moist; moderate fine and medium blocky structure; very hard, friable, moderately sticky and moderately plastic; common fine and very fine roots; many fine and very fine pores; common soft masses of segregated lime; strongly effervescent; moderately alkaline (pH 8.3); clear wavy boundary. (12 to 18 inches thick)
C--28 to 35 inches; weak red (10R 5/2) silty clay; weak red (10R 4/2) moist; extremely hard, very firm, moderately sticky and very plastic; few fine and very fine roots; many fine and very fine pores; few shale fragments; strongly effervescent; strongly alkaline; diffuse boundary.
Cr--35 to 60 inches; clay shale; few roots between plates in the upper few inches.
TYPE LOCATION: Cascade County, Montana; 300 feet west and 600 feet north of SE corner of SW1/4 of sec. 26, T.18N., R.SE.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact is usually 30 to 40 inches, but ranges from 20 to 40 inches. The solum is 20 to 30 inches thick and includes all or nearly all the regolith. The control section is silty clay loam, clay loam, silty clay, or clay and has 35 to 50 percent clay and 40 to 50 percent silt plus very fine sand. The mean annual soil temperature ranges from 41 to 44 degrees F. The mollic epipedon is 7 to 10 inches thick.
The Al or Ap horizon has hue of 7.5YR or 5YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3. It has slightl effervescence. Reaction is neutral to moderately alkaline.
The Bw horizon has hue of 5YR through 10R, value of 5 or 6 dry, 4 or 5 moist, and chroma of 3 through 6. It has moderate or strong blocky structure and has prismatic structure in some pedons. This horizon is slightly to strongly effervescent; Reaction is slightly or moderately alkaline.
The Bk horizon has hue of 5YR through 10R. It has weak to moderate blocky structure and has moderate to strong effervescence with few to common masses of segregated lime. Reaction is slightly or moderately alkaline.
COMPETING SERIES: These are the Litimber and Loken series. These soils are very deep.
GEOGRAPHIC SETTING: Timberg soils are on high upland sedimentary plains and foothills at elevations of 3,400 to 4,600 feet. They formed in reddish colored, clayey materials weathered from the underlying reddish colored, weakly consolidated shale. Slope is 0 to 45 percent. The climate is cool, moist-semiarid, with long, cold dry winters and moist springs and summers. Mean annual precipitation ranges from 14 to 19 inches, most of which falls in spring or early summer. Mean annual temperature ranges from 40 to 42 degrees F., mean January temperature from 18 to 25 degrees F., and mean July temperature from 64 to 66 degrees F. The (32 degree F.) growing season is 100 to 135 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Armington, Castner, Kuro and Ringling soils and the competing Big Timber Darret and Litimber soils. Armington soils are heavy clay soils. Castner soils have a lithic contact within depth of 20 inches. Kuro soils have an ochric epipedon and have a parhlithic contact within depth of 20 inches. Ringling soils have a fragmental particle-size class.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used for both nonirrigated cropland and for range. The principal native vegetation is bluebunch wheatgrass, green needlegrass, western wheatgrass, Fairie junegrass and Idaho fescue.
DISTRIBUTION AND EXTENT: Timberg soils occur along the foothills of the Rocky Mountains in western Montana, and are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Cascade County, Montana, 1969.