LOCATION MIKKALO                 OR+WA

Established Series
Rev. TAD/AON/RWL
09/2019

MIKKALO SERIES

Landscape-- hills, plateaus, canyonlands
Landform--hillslopes, structural benches, canyons
Slope--0 to 60 percent
Parent material--loess and a small amount of volcanic ash in the upper part
Mean annual precipitation--about 250 mm
Mean annual air temperature--about 10 degrees C
Depth class--moderately deep
Drainage class--well drained
Soil moisture regime--aridic
Soil temperature regime--mesic
Soil moisture subclass--xeric

TAXONOMIC CLASS: Coarse-silty, mixed, superactive, mesic Calcidic Haploxerolls

TYPICAL PEDON: Mikkalo silt loam in an area of grassland

A1--0 to 8 cm; silt loam, grayish brown (10YR 5/2) dry, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; neutral (pH 6.8); gradual wavy boundary

A2--8 to 28 cm; silt loam, grayish brown (10YR 5/2) dry, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; neutral (pH 6.8); gradual wavy boundary

Bw1--28 to 41 cm; silt loam, brown (10YR 5/3) dry, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; slightly alkaline (pH 7.4); gradual wavy boundary

Bw2--41 to 69 cm; silt loam, pale brown (10YR 6/3) dry, brown (10YR 4/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; slightly alkaline (pH 7.6); gradual smooth boundary

Bk1--69 to 89 cm; silt loam, very pale brown (10YR 7/3) dry, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; many very fine tubular pores; 5 percent gravel 2 to 10 mm in diameter; slightly effervescent; slightly alkaline (pH 7.8); abrupt wavy boundary

Bk2--89 to 97 cm; silt loam, very pale brown (10YR 8/2) dry, brown (10YR 5/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; few very fine tubular pores; 15 percent gravel 2 to 10 mm in diameter; strongly effervescent; few streaks and splotches of soft powdery lime; moderately alkaline (pH 8.4); gradual wavy boundary

2R--97 cm; lime-coated basalt

TYPE LOCATION: Gilliam County, Oregon; about 6 m north of gravel road in the SE1/4SE1/4NE1/4 of section 19, T. 1 S., R. 21 E.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature--10 to 12 degrees C
Soil moisture--usually dry in all parts between depths of 10 and 30 cm one-half to three-fourths of the time when soil temperature is above 5 degrees C
Depth to bedrock--50 to 100 cm
Thickness of mollic epipedon--18 to 41 cm
Particle-size control section--silt loam; 8 to 12 percent clay; less than 15 percent material coarser than very fine sand
Depth to secondary carbonates--41 to 75 cm

A horizon
Value--4 or 5 dry, 2 or 3 moist
Chroma--2 or 3 dry or moist
Structure--granular, platy, subangular blocky
Reaction--6.1 to 7.3
Combined thickness--15 to 41 cm

Bw horizon
Value--5 or 6 dry, 3 or 4 moist
Chroma--3 or 4 dry or moist
Structure--subangular blocky, prismatic
Reaction--6.1 to 8.4
Combined thickness--10 to 58 cm

Bk horizon
Value--6 to 8 dry, 4 to 6 moist
Chroma--2 or 3 dry or moist
Reaction--7.4 to 9.0
Calcium carbonate content--5 to 15 percent
Combined thickness--18 to 56 cm

COMPETING SERIES:
Ellisforde--no lithic contact within a depth of more than 150 cm; lacustrine sediment at a depth of 50 to 100 cm
Hodad--calcic horizon and secondary carbonates at a depth of 18 to 51 cm
Neeley--no lithic contact within a depth of more than 150 cm; calcic horizon and secondary carbonates at a depth of 18 to 66 cm
Ritzville--no lithic contact within a depth of more than 150 cm

GEOGRAPHIC SETTING:
Elevation--90 to 850 m
Climate--semiarid; cool, moist winters; warm, dry summers
Mean annual precipitation--230 to 310 mm
Mean January air temperature--about -2 degrees C
Mean July air temperature--about 22 degrees C
Mean annual air temperature--about 9 to 12 degrees C
Frost-free season--115 to 180 days

GEOGRAPHICALLY ASSOCIATED SOILS:
Ritzville--in similar positions

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained
Saturated hydraulic conductivity (Ksat)--moderately high

USE AND VEGETATION:
Use--production of small grain, livestock grazing
Native vegetation--bluebunch wheatgrass, green rabbitbrush, big sagebrush, balsamroot, yarrow

DISTRIBUTION AND EXTENT: Eastern Oregon and eastern Washington; MLRA 8; moderate extent

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Morrow County, Oregon; 1977

REMARKS:
Diagnostic horizons and other features in this pedon
*Mollic epipedon--zone from the surface to a depth of 41 cm
*Cambic horizon--zone from 41 to 69 cm
*Secondary carbonates--zone from 69 to 97 cm

---

National Cooperative Soil Survey
U.S.A.