LOCATION LARKIN ID+WA
Established Series
Rev. RJB/CKN/RWL/SHB
06/2016
LARKIN SERIES
Landscape--Columbia hills
Landform--loess hills, structural benches, plateaus
Slope--0 to 60 percent
Parent material--typically loess, but in some areas loess over residuum derived from basalt or loess mixed with a small amount of volcanic ash in upper part
Mean annual air temperature--about 8 degrees C
Mean annual precipitation--about 585 mm
Depth class--very deep
Drainage class--well drained
Soil moisture regime--xeric
Soil temperature regime--mesic
Soil moisture subclass--typic
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Ultic Argixerolls
TYPICAL PEDON: Larkin silt loam, forested, on a 22-percent, convex, west-facing slope at an elevation of 925 m (The soil was described on April 28, 1977.)
Oi--0 to 3 cm; slightly decomposed needles, leaves, grass, and twigs
Oe--3 to 4 cm; moderately decomposed needles, leaves, grass, and twigs
A1--4 to 15 cm; silt loam, dark grayish brown (10YR 4/2) dry, very dark brown (10YR 2/2) moist; weak fine subangular blocky structure parting to fine granular; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, fine, and medium and few coarse roots; many very fine and fine irregular pores; worm holes throughout; neutral (pH 6.6); clear wavy boundary
A2--15 to 28 cm; silt loam, brown (10YR 5/3) dry, very dark grayish brown (10YR 3/2) moist; weak fine and medium subangular blocky structure parting to moderate fine and medium granular; slightly hard, friable, slightly sticky and slightly plastic; many very fine and medium and common coarse roots; many very fine and fine and few medium continuous tubular pores; worm holes throughout; slightly acid (pH 6.4); clear wavy boundary
AB--28 to 43 cm; silt loam, brown (10YR 5/3) dry, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine, fine, and medium and common coarse roots; many very fine and fine and common medium continuous tubular pores; few light gray (10YR 7/2) silt coatings on faces of peds; worm holes throughout; slightly acid (pH 6.4); clear wavy boundary
Bt1--43 to 58 cm; silt loam, yellowish brown (10YR 5/4) dry, dark yellowish brown (10YR 4/4) moist; weak medium prismatic structure parting to moderate fine and medium subangular blocky; hard, firm, slightly sticky and slightly plastic; common very fine and coarse and many fine and medium roots; many very fine and fine and common medium continuous tubular pores; few faint brown (7.5YR 5/4) clay films on faces of peds; light gray (10YR 7/2) silt coating on faces of peds; worm holes throughout; slightly acid (pH 6.2); clear smooth boundary
Bt2--58 to 94 cm; silt loam, yellowish brown (10YR 5/4) dry, dark yellowish brown (10YR 4/4) moist; moderate medium and coarse prismatic structure parting to strong fine subangular blocky; very hard, very firm, slightly sticky and slightly plastic; many very fine, common fine and medium, and few coarse roots; many very fine and fine and common medium continuous tubular pores; common faint brown (7.5YR 5/4) clay films on faces of peds; common light gray (10YR 7/2) silt coating on faces of peds; worm holes throughout; moderately acid (pH 6.0); clear wavy boundary
Btc1--94 to 130 cm; silt loam, yellowish brown (10YR 5/4) dry, dark yellowish brown (10YR 4/4) moist; moderate medium and coarse prismatic structure parting to moderate fine subangular blocky; very hard, very firm, sticky and plastic; many very fine and common fine, medium, and coarse roots; many very fine and common fine, medium, and coarse roots; many very fine, fine, and medium continuous tubular pores; many distinct reddish brown (5YR 5/4) clay films on faces of peds and in pores; common light gray (10YR 7/2) silt coating on faces of peds; many fine (less than 2 mm) iron and manganese concretions; worm holes throughout; moderately acid (pH 6.0); gradual wavy boundary
Btc2--130 to 157 cm; silt loam, yellowish brown (10YR 5/4) dry, dark yellowish brown (10YR 4/4) moist; weak coarse prismatic structure parting to moderate fine subangular blocky; very hard, firm, moderately sticky and slightly plastic; common fine, medium, and coarse and many very fine roots; many very fine, fine, and medium continuous tubular pores; many prominent and distinct reddish brown (5YR 5/4) clay films on faces of peds and in pores; many fine (less than 2 mm) iron and manganese concretions; few light gray (10YR 7/2) silt coating on faces of peds; worm holes throughout; slightly acid (pH 6.2)
TYPE LOCATION: Latah County, Idaho, about 4 km north of Viola, Idaho; about 122 m south and 357 m west of the northeast corner of section 30, T. 41 N., R. 5 W.; latitude 46.8728398, longitude -117.0065100, datum WGS 84 (coordinates estimated from PLSS data)
RANGE IN CHARACTERISTICS:
Thickness of mollic epipedon--25 to 50 cm
Base saturation--50 to 75 percent in some part between depths of 25 and 75 cm
Soil moisture control section--dry 45 to 75 days
Mean annual soil temperature--8 to 12 degrees C
Content of clay in particle-size control section (weighted average)--20 to 35 percent
Oi horizon
Thickness--0 to 5 cm
Oe horizon
Thickness--0 to 3 cm
A horizon, and Ap horizon (where present)
Hue--10YR, 7.5YR
Value--4 or 5 dry, 2 or 3 moist
Chroma--2 or 3 dry or moist
Texture--silt loam, silty clay loam
Content of clay--15 to 27 percent
Content of rock fragments--0 to 5 percent
Reaction--5.1 to 7.3
Combined thickness--10 to 45 cm
AB horizon (where present)
Hue--10YR, 7.5YR
Value--4 to 6 dry, 2 to 4 moist
Chroma--2 or 3 dry, 3 or 4 moist
Texture--silt loam, silty clay loam
Content of clay--15 to 27 percent
Content of rock fragments--0 to 5 percent
Reaction--5.6 to 7.3
Thickness--0 to 25 cm
Bt and Btc horizons
Hue--10YR, 7.5YR
Value--4 to 6 dry, 3 to 5 moist
Chroma--3 to 6 dry or moist
Texture--silt loam, silty clay loam
Content of clay--18 to 35 percent
Content of rock fragments--0 to 5 percent
Reaction--5.6 to 7.3
Combined thickness of Bt horizon--40 to 95 cm
Combined thickness of Btc horizon--25 to 50 cm or more
2Bt/E horizon (where present)
Bt part
Hue--10YR, 7.5YR
Value--3 or 4 dry or moist
Chroma--3 or 4 moist
Content of clay--20 to 24 percent
Content of rock fragments--0 to 5 percent
E part
Value--5 to 7 dry or moist
Chroma--3 or 4 dry or moist
Reaction--6.1 to 7.3
2Bt horizon (where present)
Value--5 or 6 dry, 3 or 4 moist
Chroma--3 to 6 dry or moist
Content of clay--27 to 35 percent
Content of rock fragments--0 to 5 percent gravel
Reaction--5.6 to 7.3
COMPETING SERIES:
Hillsboro--mean annual soil temperature of 12 to 13 degrees C; stratified loamy and sandy material below a depth of 100 cm
GEOGRAPHIC SETTING:
Elevation--365 to 1125 m in Idaho; as high as 1375 m in Washington
Mean annual precipitation--460 to 760 mm
Mean annual air temperature--7 to 11 degrees C
Frost-free period--90 to 180 days (9 years in 10 and 1 year in 10, respectively)
GEOGRAPHICALLY ASSOCIATED SOILS:
Driscoll--on summits and shoulder slopes; fine particle-size class; moderately well drained; albic horizon
Latahco--formed in alluvium; on bottomland
Southwick--on backslopes; albic horizon
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained
Saturated hydraulic conductivity (Ksat)--moderately high
USE AND VEGETATION:
Use--dominantly crop production; some timber production
Potential natural vegetation--dominantly ponderosa pine, mallow ninebark, common snowberry, elk sedge, and bluebunch wheatgrass
DISTRIBUTION AND EXTENT: Northern Idaho and eastern Washington; MLRA 9; moderate extent
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Latah County, Idaho; 1944
REMARKS:
Diagnostic horizons and other features in this pedon (depths measured from top of first mineral horizon)
*Mollic epipedon--zone from 4 to 43 cm
*Argillic horizon--43 to 157 cm
*Particle-size control section--zone from 43 to 94 cm
In Clearwater County, Idaho, some areas of Larkin soil are underlain by loess and residuum derived from basalt and have 2B/E and 2Bt horizons.
Further MLRA-wide investigation is needed to determine the extent and influence of volcanic ash.
6/2016--This official series description (OSD) was updated as part of the final correlation of the Spokane County, Washington, soil survey. The formatting was updated according to SSR1 Technical Note 11--Content and Format of Official Series Descriptions (revised 12/2015).
National Cooperative Soil Survey
U.S.A.