LOCATION MILREN WYEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Ustic Paleargids
TYPICAL PEDON: Milren sandy loam-rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 2 inches; brown (10YR 5/3) sandy loam, brown (10YR 4/3) moist; weak medium granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots; 10 percent subrounded pebbles; neutral (pH 7.0); abrupt smooth boundary. (1 to 4 inches thick)
E--2 to 3 inches; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; weak medium platy structure parting to weak medium granular; soft, very friable, nonsticky and nonplastic; many very fine, fine, and few medium roots; 10 percent subrounded pebbles; mildly alkaline (pH 7.4); abrupt broken boundary. (1/2 to 2 inches thick)
Bt--3 to 11 inches; brown (7.5YR 4/4) sandy clay, brown (10YR 4/3) moist; moderate medium prismatic structure parting to strong medium subangular blocky; very hard, firm, very sticky and very plastic; common very fine, fine, and few medium roots; continuous thick clay films on all faces of peds; 5 percent subrounded pebbles; moderately alkaline (pH 8.0); gradual wavy boundary. (6 to 12 inches thick)
Btk--11 to 16 inches; pale brown (10YR 6/3) sandy clay loam, brown (10YR 5/3) moist; weak medium prismatic structure parting to moderate medium subangular blocky; slightly hard, very friable, slightly sticky and slightly plastic; common very fine, fine, and few medium roots; few thin clay films on faces of peds; strongly effervescent, carbonates disseminated and as few large threads, seams, and soft masses; moderately alkaline (pH 8.2); clear wavy boundary. (5 to 10 inches thick)
Bk--16 to 23 inches; very pale brown (10YR 7/3) loam, pale brown (10YR 6/3) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; few very fine, fine, and medium roots; violently effervescent, carbonates disseminated and as many large soft masses and in threads and seams; 2 percent subrounded fine pebbles; strongly alkaline (pH 8.6); gradual wavy boundary. (5 to 25 inches thick)
C1--23 to 51 inches; very pale brown (10YR 7/4) fine sandy loam, yellowish brown (10YR 5/4) moist; massive; soft, very friable, nonsticky and nonplastic; strongly effervescent, carbonates disseminated; 2 percent semirounded pebbles; strongly alkaline (pH 8.6); gradual wavy boundary.
C2--51 to 56 inches; pale brown (10YR 6/3) fine sandy loam, brown (10YR 5/3) moist; massive; soft, very friable, nonsticky and nonplastic; slightly effervescent, carbonates disseminated; 2 percent semirounded pebbles; strongly alkaline (pH 8.6); clear wavy boundary.
C3--56 to 65 inches; very pale brown (10YR 7/3) loamy fine sand, pale brown (10YR 6/3) moist; massive; soft, very friable, nonsticky and nonplastic; slightly effervescent, carbonates disseminated; strongly alkaline (pH 8.6)
TYPE LOCATION: Fremont County, Wyoming; approximately 480 feet south and 1,300 feet east of the NW corner of sec. 4, T. 31 N., R. 90 W.
RANGE IN CHARACTERISTICS: Depth to the base of the argillic horizon ranges from 13 to 25 inches. Depth to bedrock exceeds 60 inches. The mean annual soil temperature ranges from 36 to 45 degrees F., and the mean summer soil temperature ranges from 59 to 62 degrees F. Rock fragments range from 0 to 15 percent throughout the entire soil to 60 inches or more.
The A horizon has hue of 2.5Y or 10YR, value of 4 through 6 dry, 3 through 5 moist, and chroma of 2 or 3. EC ranges from 0 to 2 mmhos. Reaction is neutral or mildly alkaline.
The E horizon has hue of 2.5Y or 10YR, value of 6 or 7 dry, 4 through 6 moist, and chroma of 2 or 3. Texture is loam, sandy loam, or fine sandy loam. EC ranges from 0 to 2 mmhos. Reaction is neutral or mildly alkaline.
The Bt argillic horizon has hue of 10YR or 7.5YR, value of 4 through 6 dry, 3 through 5 moist, and chroma of 2 through 4. Texture is clay, sandy clay, or heavy clay loam with 35 to 60 percent clay. Reaction ranges from neutral through moderately alkaline.
The Btk horizon has hue of 10YR or 7.5YR, value of 5 or 6 dry, 4 or 5 moist, and chroma of 2 through 4. Texture is clay, sandy clay, clay loam, or sandy clay loam. This horizon is typically part of the diagnostic argillic. Clay ranges from 30 to 60 percent but averages more than 35 percent when prorated for the entire argillic horizon. EC ranges from 0 to 2 mmhos. Reaction is moderately or strongly alkaline.
The Bk horizon has hue of 2.5Y or 10YR, value of 5 through 7 dry, 4 through 6 moist, and chroma of 2 through 4. Texture is loam, clay loam, sandy clay loam, sandy loam, or fine sandy loam. Calcium carbonate equivalent typically ranges from 4 to 14 percent but may range to 20 percent in discontinuous strata. This horizon does not meet the requirements of a calcic. EC ranges from 0 to 4 mmhos. Reaction is moderately or strongly alkaline.
The C horizon has hue of 5Y through 10YR, value of 5 through 7 dry, 4 through 6 moist, and chroma of 2 through 4. Texture is typically fine sandy loam, sandy loam, loam, or sandy clay loam above 40 inches. Thin strata of coarser material may occur below 40 inches. EC ranges from 0 to 4 mmhos. Reaction is moderately or strongly alkaline.
COMPETING SERIES: These are the Coalmont and Phillips series. Coalmont soils have a paralithic contact at 20 to 40 inches. Phillips soils have a high bulk density till at a depth less than 40 inches.
GEOGRAPHIC SETTING: Milren soils are on relict fan aprons, fan piedmonts, and terraces in cold intermountain basins and uplands. These soils formed in moderately fine textured alluvium weathered from clay-bearing sedimentary rock. Slopes range from 0 to 10 percent. Elevations range from 6,000 to 7,800 feet. The mean annual precipitation ranges from 9 to 14 inches of which about half falls as snow and rain during April, May, and early June. The mean annual temperature ranges from about 34 to 45 degrees F. The frost-free season is estimated to range from 80 to 110 days depending upon elevation, aspect, and air drainage.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Abston, Bluerim, Bosler, Cragosen, and Rock River soils and the competing Coalmont soils. Abston soils have over 15 percent exchangeable sodium in the Bt horizon and have bedrock at 20 to 40 inches. Bosler soils have fine loamy over sandy or sandy-skeletal substrata control sections. Cragosen soils are loamy-skeletal and do not have any diagnostic subsurface horizons. Rock River soils have less than 35 percent clay in the control section and lack the abrupt textural clay increase.
DRAINAGE AND PERMEABILITY: Well drained; slow or medium runoff; slow permeability.
USE AND VEGETATION: Rangeland and wildlife habitat. Native vegetation is thickspike wheatgrass, big sagebrush, bottlebrush squirreltail, Indian ricegrass, and mutton bluegrass.
DISTRIBUTION AND EXTENT: South-central and southwestern Wyoming. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Sublette County, Wyoming; 1985.