LOCATION LARIM WY+MT
Established Series
Rev. PSD/KLS
05/2023
LARIM SERIES
The Larim series consists of very deep, well drained soils that formed in mixed alluvium generated during the late Pleistocene. They are on relict terraces, escarpment caps, and remnant pediment toeslopes. Slopes are typically 2 to 15 percent but range from 0 to 35 percent. The mean annual precipitation is about 305 mm and the mean annual air temperature is about 8 degrees C.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Ustic Calciargids
TYPICAL PEDON: Larim very gravelly sandy loam-rangeland on a SW facing terrace with slope of 3 percent. (Colors are for dry soil unless otherwise stated.)
A--0 to 8 cm; brown (10YR 5/3) very gravelly sandy loam, brown (10YR 4/3) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine, fine, and medium roots; 35 percent rounded gravel; slightly effervescent, finely disseminated carbonates; slightly alkaline (pH 7.6); abrupt smooth boundary. (5 to 15 cm thick)
Bt--8 to 20 cm; brown (7.5YR 5/4) very gravelly sandy clay loam, brown (10YR 4/3) moist; weak coarse prismatic structure parting to moderate medium subangular blocky; slightly hard, friable, sticky and plastic; thin continuous clay films on all faces of peds; common fine, very fine, and medium roots; 50 percent rounded gravel; noneffervescent; neutral; clear wavy boundary. (0 to 25 cm thick)
Btk--20 to 38 cm; brown (10YR 5/3) very gravelly 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; thin common clay films on faces of peds, carbonates masking some clay films on vertical faces of peds; common fine, very fine, and medium roots; 50 percent rounded gravel; strongly effervescent, few fine and medium soft masses of lime; moderately alkaline; abrupt smooth boundary. (8 to 30 cm thick)
2Bk--38 to 86 cm; very pale brown (10YR 7/3) very gravelly loamy sand, pale brown (10YR 6/3) moist; single grained except where weakly cemented by carbonates; slightly hard, very friable, few very fine, fine, and medium roots; 50 percent rounded gravel; violently effervescent, many fine and medium soft masses and weak pendants of lime; moderately alkaline; gradual wavy boundary. (38 to 64 cm thick)
2C--86 to 152 cm; brownish yellow (10YR 6/6) very gravelly loamy sand, yellowish brown (10YR 5/4) moist; single grained; slightly hard, very friable; 50 percent rounded gravel; strongly effervescent, finely disseminated carbonates; moderately alkaline.
TYPE LOCATION: Washakie County, Wyoming; NE1/4, NE1/4, sec. 21, T. 45 N., R. 95 W.
RANGE IN CHARACTERISTICS:
Soil moisture - usually dry, but mostly moist during May and June
Mean annual soil temperature - 9 to 12 degrees C
Depth to the base of the argillic horizon - 28 to 50 cm
Depth to continuous horizons of carbonate accumulation - 10 to 33 cm
Depth to a lithologic discontinuity (very gravelly or extremely gravelly sand or loamy sand) - 28 to 50 cm
Particle-size control section:
Clay content - 22 to 35 percent
Sand content - more than 35 percent fine sand or coarser
Rock fragment content - 35 to 60 percent--35 to 60 percent rounded gravel, 0 to 10 percent rounded cobbles
A horizon
Hue: 2.5Y through 7.5YR
Value: 4 through 6 dry, 3 through 5 moist
Chroma: 2 or 3 dry or moist
Organic carbon content: more than 0.6 percent in this horizon at 5 to 10 cm deep, but the horizon does not meet the requirements of a mollic epipedon in color when it exceeds 10 cm in thickness.
Texture: sandy loam or loam
Rock fragment content: 20 to 45 percent rounded gravel
Reaction: pH 6.1 to 7.8
Bt horizon
Hue: 2.5Y through 7.5YR
Value: 4 through 6 dry, 3 through 5 moist
Chroma: 3 or 4 dry or moist
Texture: sandy clay loam or clay loam
Rock fragment content: 35 to 60 percent--35 to 60 percent rounded gravel, 0 to 10 percent rounded cobbles
Reaction: pH 6.6 to 7.8
Btk horizon
Hue: 2.5Y through 7.5YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 or 4 dry or moist
Texture: sandy clay loam or clay loam
Rock fragment content: 35 to 60 percent--35 to 60 percent rounded gravel, 0 to 10 percent rounded cobbles
Reaction: pH 7.9 to 9.0
2Bk horizon
Hue: 2.5Y through 10YR
Value: 6 or 7 dry, 5 or 6 moist
Chroma: 2 through 4, dry or moist
Texture: loamy sand or sand
Calcium carbonate equivalent: 7 to 14 percent, qualifying as a calcic horizon
Rock fragment content: 40 to 80 percent--40 to 80 percent rounded gravel, 0 to 10 percent rounded cobbles
Reaction: pH 7.9 to 9.0
C horizon
Hue: 2.5Y through 10YR
Value: 6 or 7 dry, 5 or 6 moist
Chroma: 4 through 6, dry or moist
Texture: loamy sand or sand
Calcium carbonate equivalent: 7 to 14 percent, qualifying as a calcic horizon
Rock fragment content: 40 to 80 percent--40 to 80 percent rounded gravel, 0 to 10 percent rounded cobbles
Reaction: pH 7.9 to 9.0
COMPETING SERIES:
Musofare (NM) - are moderately deep
Samala (CO) - have an argillic base more than 70 cm deep
Sedillo (NM) - are dry during
May and June
GEOGRAPHIC SETTING:
Landform - relict terraces, escarpment caps, and remnant pediment toeslopes
Elevation - 1,450 to 2,250
Parent material - mixed alluvium generated during the late Pleistocene
Mean annual air temperature - 7 to 9 degrees C
Mean annual precipitation - 280 to 410 mm
Precipitation pattern - peak periods of precipitation occur during spring and summer
Frost-free period - 110 to 150 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderate to rapid permeability.
USE AND VEGETATION: Larim soils are used as native pastureland. Native vegetation is needleandthread grass, pricklypear, fringed sagebrush, blue grama, Indian ricegrass, bluebunch wheatgrass, yucca.
DISTRIBUTION AND EXTENT: Larim soils are of moderate extent in north central Colorado, southcentral Montana and northern Wyoming; MLRAs 32, 49, 58A, 67B.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Larimer County, Colorado, 1971
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 8 cm (A horizon)
Argillic horizon - 8 to 38 cm (Bt and Btk horizons)
Lithologic discontinuity - 38 to 152 cm (2Bk and 2C horizons)
Particle-size control section - 8 to 38 cm (Bt and Btk horizons)
Larim soils have a mesic soil temperature regime and an aridic soil moisture regime bordering on ustic.
Converted to metric, formatting updated to current standards, and competing series section updated. 04/2020
National Cooperative Soil Survey
U.S.A.