LOCATION MOBU                    WA

Established Series
Rev. KH/TDT
01/2011

MOBU SERIES

The Mobu series consists of very deep, well drained soils formed in loess over glaciolacustrine sediment. These soils are on terraces and terrace escarpments. Slopes are 3 to 45 percent. The mean annual precipitation is about 13 inches, and the mean annual air temperature is about 46 degrees F.

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

TYPICAL PEDON: Mobu silt loam - rangeland. (Colors are for dry soil unless otherwise stated. All textures are apparent field textures).

A1-- 0 to 2 inches; grayish brown (10YR 5/2) silt loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic, many very fine and fine roots, many very fine and fine tubular and interstitial pores; slightly acid (pH 6.4); abrupt smooth boundary.

A2-- 2 to 11 inches; grayish brown (10YR 5/2) silt loam, very dark brown (10YR 2/2) moist; weak medium prismatic structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine tubular and interstitial pores; neutral (pH 6.8); clear smooth boundary. (Combined thickness of the A horizon is 10 to 20 inches)

Bw-- 11 to 15 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots, many very fine and fine tubular and interstitial pores; neutral (pH 7.0); clear smooth boundary. (4 to 22 inches thick)

2C-- 15 to 30 inches; light gray (10YR 7/2) silt loam, grayish brown (10YR 5/2) moist, massive; hard, firm, slightly sticky and moderately plastic, few very fine and fine roots; common very fine and tubular and interstitial pores; common medium to large faint dark grayish brown (10YR 4/2) relic redox features; slightly alkaline (pH 7.4); clear wavy boundary (2 to 22 inches thick)

2Ck1-- 30 to 36 inches; light gray (2.5Y 7/2) silt loam, grayish brown (2.5Y 5/2) moist; massive; very hard, very firm, slightly sticky and moderately plastic; few very fine and fine roots; common very fine and fine interstitial pores; soft powdery secondary carbonates in seams and in pores; common medium to large faint dark grayish brown (10YR 4/2) relic redox fearures; slightly effervescent; moderately alkaline (pH 8.0); abrupt smooth boundary.

2Ck2-- 36 to 60 inches; light gray (2.5Y 7/2) silt loam, grayish brown (2.5Y 5/2) moist; massive; very hard, very firm, slightly sticky and moderately plastic; few very fine and fine roots; common very fine and fine interstitial pores; common medium to large faint dark grayish brown (10YR 4/2) relic redox features; strongly effervescent; moderately alkaline (pH 8.0). (Combined thickness of the 2Ck horizon is more than 25 inches thick)

TYPE LOCATION: Okanogan County, Washington; about 1 mile east of the community of Synarep; about 260 west and 300 feet north of the southeast corner sec. 16, T. 35N., R 28E. (Latitude 119 degrees, 19 minutes, 41 seconds North; longtitude 48 degrees, 31 minutes, 33 seconds West NAD 83).

RANGE IN CHARACTERISTICS: The mean annual soil temperature is 46 to 50 degrees F. The soils are usually moist, but are dry in all parts between a depth of 8 and 24 inches for 90 to 105 consecutive days following the summer solstice. Depth to soft powdery secondary carbonate accumulations is 18 to 36 inches. The particle-size control section is 10 to 18 percent clay and less than 15 percent coarser than fine sand or coarser by weighted average. The mollic epipedon is 10 to 20 inches thick.

A horizon:
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3 dry or moist

Bw horizon:
Hue: 10YR or 2.5Y
Value: 5 to 7 dry, 3 to 5 moist
Chroma: 2 to 4 dry or moist
Reaction: neutral to slightly alkaline

2C horizon:
Hue: 10YR or 2.5Y
Value: 5 to 7 dry, 3 to 5 moist
Chroma: 2 to 4 dry or moist
Reaction: neutral to slightly alkaline

2Ck horizons:
Value: 6 or 7 dry, 4 to 6 moist
Chroma: 2 to 4 dry or moist
Texture: stratified very fine sandy loam, silt loam and silty clay loam.

COMPETING SERIES: This is the Olical series. Olical soils are deep or very deep to bedrock and are moderately to strongly alkaline in the lower part of the subsoil.

GEOGRAPHIC SETTING: Mobu soils are on terraces and terrace escarpments which are commonly dissected. These soils formed in loess over calcareous glaciolacustrine sediments. Slopes are 3 to 45 percent. Elevation is 1,200 to 3,500 feet. The climate is characterized by warm, dry summers and cold, moist winters. The mean annual precipitation is 11 to 14 inches. The mean January temperature is about 25 degrees F; mean July temperature is about 70 degrees F; and the mean annual air temperature is 46 to 50 degrees F. The frost-free season is 120 to 135 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Conconully, Disautel, Emdent, Ewall, Haley, and Owhi series. Conconully, Disautel, and Owhi soils are coarse-loamy. Emdent soils are somewhat poorly drained and have a sodium adsorption ratio greater than 13 in the upper 20 inches. Ewall soils are sandy. Haley soils are coarse-loamy over sandy or sandy-skeletal.

DRAINAGE AND PERMEABILITY: Well drained, slow to very rapid runoff; moderate permeability.

USE AND VEGETATION: Principal uses are hay and pasture, dryland, small grains, domestic livestock grazing, and wildlife habitat. The native vegetation is bluebunch wheatgrass, Idaho fescue, Sandberg bluegrass, threetip sagebrush, rabbitbrush, and arrowleaf balsamroot. Some areas have widely scattered ponderosa pine.

DISTRIBUTION AND EXTENT: North-central Washington. MLRA 8. The series is of slight extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Okanogan County, Washington, 2008.

REMARKS: Diagnostic horizon and features recognized in this pedon:
Mollic epipedon from the surface to 11 inches
Some pedons have a cambic horizon
Depth to secondary calcium carbonate accumulation: 30 inches
This soil was separated from the Nespelem series because Nespelem is currently defined as having a duripan.

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National Cooperative Soil Survey
U.S.A.