LOCATION RATTLER MTEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive Ustic Argicryolls
TYPICAL PEDON: Rattler stony loam - native sod. (Colors are for dry soil unless otherwise noted.)
A--0 to 7 inches; dark gray (10YR 4/1) stony loam, very dark brown (10YR 2/2) moist; weak fine crumb structure grading in lower part to medium subangular blocky structure that separates to moderate fine granular structure; soft grading to slightly hard, very friable, nonsticky, nonplastic grading to slightly sticky, slightly plastic; many very fine roots; many very fine and fine interstitial pores; 15 percent stones and cobbles; noncalcareous; neutral; clear wavy boundary.
Bt--7 to 13 inches; reddish brown (5YR 4/4) clay, dark reddish brown (5YR 3/3) moist; moderate medium and coarse subangular blocky structure that separates to fine subangular blocky structure; very hard, very firm, very sticky, very plastic; many very fine roots; common very fine and fine tubular pores; varnish-like coatings on all peds; 10 percent stones and cobbles; noncalcareous; neutral; clear wavy boundary. (5 to 10 inches thick)
Btk--13 to 30 inches; reddish brown mottled with reddish brown (5YR 5/4) and yellowish brown (10YR 5/4) clay grading to gravelly clay in the lower part, mixed reddish brown (5YR 4/4) and strong brown (7.5YR 5/6) moist; moderate medium and fine subangular blocky structure; very hard, firm, very sticky, very plastic; few very fine roots; few very fine and fine tubular pores; varnish-like coatings on all peds; 10 percent gravel and cobbles becoming 20 percent in lower part; strongly calcareous with lime crusts on lower side of rock fragments in upper part and entirely around some rock fragments in lower part; moderately alkaline; gradual irregular boundary. (10 to 20 inches thick)
2Bk--30 to 38 inches; reddish yellow (5YR 6/6) very gravelly clay, yellowish red (5YR 5/6) moist; weak medium subangular blocky structure; very hard, firm, moderately sticky, very plastic; few very fine roots and tubular pores; 50 percent gravel and cobbles; very strongly calcareous with lime crusts coating rock fragments; moderately alkaline; gradual boundary. (5 to 10 inches thick)
3C1--38 to 41 inches; pink (5YR 8/4) gravelly clay loam, reddish yellow (5YR 6/6) moist; massive; slightly hard, friable, sticky, plastic; strongly calcareous; moderately alkaline; abrupt boundary.
4C2--41 to 55 inches; light reddish brown (5YR 6/4) clay, reddish yellow (5YR 6/6) with thin strata of weak red (10R 5/4) moist; massive; very hard, very firm, very sticky, very plastic; strongly calcareous; moderately alkaline.
TYPE LOCATION: Granite County, Montana; 1,400 feet south and 500 feet east of NW corner of sec. 22, T.11N., R.12W.
RANGE IN CHARACTERISTICS: The hue in the B and C horizons is 7.5YR through 10R. Depth to calcareous soil is 10 to 24 inches. Depth to the very gravelly clay horizon is 20 to 36 inches. Mean annual soil temperature is 44 to 47 degrees F. and average summer soil temperature is 55 to 59 degrees F.
The A horizon has hue of 10YR through 5YR, value of 3 or 4 dry and chroma of 1 or 2.
The Bt horizon has hue of 7.5YR through 10R, value of 4 or 5 dry, 3 or 4 moist, and chroma of 3 through 5. It contains 35 to 60 percent clay and 10 to 30 percent rock fragments. CaC03 equivalent in zone of lime accumulation is estimated at 5 to 15 percent.
COMPETING SERIES: These are the Bangtail, Bridger, Duckcreek, Echard, Melville, Mollet, Sevier, Sicklesteets, Sluice, Tarrete and Terrad series. Bangtail, Duckcreek, and Sevier soils have a paralithic contact at 20 to 40 inches. Bridger, Echard, and Melville soils have hue yellower than 7.5YR and the Echard soils have estimated more than 60 percent ash materials. Mollet soils do not have a zone of lime accumulation. Sevier soils Sicklesteets and Sluice soils have ochric epipedons. Tarrete soils have more than 60 percent clay and have slickenside structural aggregates. Terrad soils have summer soil temperature warmer than 59 degrees F.
GEOGRAPHIC SETTING: Rattler soils are on high outwash benches and fans at elevations of 4,200 to 5,500 feet. Mean annual precipitation is 16 to 22 inches. Mean annual temperature is 39 to 42 degrees F. Mean summer temperature is less than 60 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Donald and Loberg soils and the competing Sicklesteets and Terrad soils. Donald soils have hue of 7.5YR and yellower. Loberg soils have ochric epipedons developed under forest cover.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: Chiefly for range but more gently sloping, stone-free phases are used for both irrigated and dryland farming with hay and small grains the principal crops. Native vegetation is bluebunch wheatgrass, Idaho fescue, rough fescue, bluegrasses, big sagebrush, lupine, and arrowleaf balsamroot.
DISTRIBUTION AND EXTENT: Widely distributed in western Montana valleys. They are extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Granite County (Philipsburg-Drummond Area), Montana, 1972.