LOCATION CHESEBRO OR

Established Series
Rev. MPK-JVC-JBF
01/2011

CHESEBRO SERIES

The Chesebro series consists of very deep, well drained soils that formed in volcanic ash flow and colluvium derived from volcanic rock. Chesebro soils are on hills and mountains. Slopes are 15 to 65 percent. The mean annual precipitation is about 330 mm and the mean annual temperature is about 6 degrees C.

TAXONOMIC CLASS: Ashy-skeletal, glassy, frigid Vitrandic Argixerolls

TYPICAL PEDON: Chesebro very cobbly ashy loam--on a mountain sloping 28 percent to the north at an elevation of 1,540 meters--rangeland. (Colors are for dry soil unless otherwise noted. When the soil was described on June 5, 2002 the soil was dry from the surface to 8 cm and moist below to about 150 cm deep.)

A1--0 to 10 cm; dark grayish brown (10YR 4/2) very cobbly ashy loam, very dark brown (10YR 2/2) moist; weak fine and very fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and many fine roots; many very fine interstitial pores; 15 percent fine gravel, 15 percent coarse gravel, 15 percent cobbles, 5 percent stones, and 5 percent boulders; neutral (pH 6.6); clear smooth boundary. (5 to 18 cm thick)

A2--10 to 23 cm; dark grayish brown (10YR 4/2) very stony ashy loam, very dark brown (10YR 2/2) moist; weak coarse and medium granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and many fine roots; many very fine interstitial and common very fine tubular pores; 10 percent fine gravel, 15 percent coarse gravel, 15 percent cobbles, and 15 percent stones; neutral (pH 6.6); clear wavy boundary. (10 to 30 cm thick)

AB--23 to 61 cm; brown (10YR 5/3) very cobbly ashy loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure parting to moderate coarse and medium granular; soft, very friable, slightly sticky and slightly plastic; many very fine and many fine roots; many very fine tubular pores; 10 percent fine gravel, 15 percent coarse gravel, 15 percent cobbles, and 10 percent stones; neutral (pH 6.8); gradual smooth boundary. (0 to 38 cm thick)

Bt1--61 to 91 cm; yellowish brown (10YR 5/4) very gravelly ashy loam, dark yellowish brown (10YR 3/4) moist; weak coarse subangular blocky structure parting to moderate medium subangular blocky; slightly hard, very friable, moderately sticky and moderately plastic; common very fine, common fine, and common medium roots; many very fine tubular pores; 10 percent fine gravel, 30 percent coarse gravel, 10 percent cobbles, and 5 percent stones; few distinct clay films on faces of peds; neutral (pH 7.0); gradual smooth boundary. (13 to 30 cm thick)

Bt2--91 to 152 cm; yellowish brown (10YR 5/4) very cobbly ashy loam, dark yellowish brown (10YR 3/4) moist; weak medium and fine subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; few very fine and few fine roots; many very fine tubular pores; 10 percent fine gravel, 10 percent coarse gravel, 15 percent cobbles, and 5 percent stones; few distinct clay films on faces of peds; neutral (pH 7.2).

TYPE LOCATION: Lake County, Oregon; in the Glass Buttes about 1.5 miles northeast of the radio tower atop the summit of Glass Butte; approximately 1,200 feet north and 1,500 feet west of the southeast corner of section 15, T. 23 S., R. 22 E.; USGS Glass Butte 7.5 minute topographic quadrangle; latitude 43 degrees 34 minutes 27.0 seconds N and longitude 120 degrees 03 minutes 39.6 seconds W;, NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter and spring, dry in summer and fall; xeric moisture regime that borders on aridic.
Mean annual soil temperature: 6 to 8 degrees C.
Mollic epipedon thickness: 50 to 76 cm.
Depth to base of argillic horizon: 114 to 150 cm.
Depth to bedrock: Greater than 150 cm.

Particle-size control section - Clay content: 22 to 32 percent.
Rock fragments: 40 to 60 percent, mainly gravel and cobbles. Lithology of fragments are volcanic rocks such as rhyolite and rhyodacite.
Volcanic glass content: 30 to 75 percent in coarse silt through fine sand fractions with more glass concentrated in the fine sand fraction.

A and AB horizons
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 2 to 4 percent.

Bt horizons
Value: 4 or 5 dry, 2 through 4 moist.
Chroma: 2 through 4, dry or moist.
Texture: Very gravelly ashy loam, very gravelly ashy sandy clay loam, very cobbly ashy loam or very cobbly ashy clay loam.
Reaction: Neutral or slightly alkaline.

COMPETING SERIES: These are the Eep, Lyonman, Monasterio, Tourn, Vetash, Warnermount and Willowak series.
Eep soils have mollic epipedons 25 to 50 cm thick and have depth to base of the argillic horizon of less than 100 cmLyonman and Tourn soils are moderately deep to paralithic contacts. Monasterio and Warnermount soils are moderately deep to lithic contacts. Vetash soils have mollic epipedons that include part of the argillic horizon and have surface horizons dominated by gravel. Willowak soils are 50 to 100 cm to paralithic contact and 76 to 100 cm to lithic contact.

GEOGRAPHIC SETTING: Chesebro soils are on hills and mountains. They typically occur on north-facing backslope positions. These soils formed in volcanic ash flow and colluvium derived from volcanic rocks such as rhyolite and rhyodacite. Slopes are 15 to 65 percent. Elevations range from 1,360 to 1,955 meters. The climate is semiarid and characterized by cool, moist winters and warm, dry summers. The mean annual precipitation is 250 to 360 mm, the mean annual temperature is 4 to 7 degrees C., and the frost-free period is 50 to 80 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cabinspring, Derallo, and Jacksplace soils. Cabinspring soils are moderately deep to lithic contacts, have a subhorizon of the argillic horizon with 40 to 50 percent clay, have an aridic moisture regime, and are on south and west-facing slopes. Derallo soils are deep to paralithic contacts, have a mollic epipedon that is less than 50 cm thick, have an aridic moisture regime, and are on south and west-facing slopes. Jacksplace soils are moderately deep to lithic contacts, have mollic epipedons that are 23 to 30 cm thick, have an aridic moisture regime, and are on lava plateaus.

DRAINAGE AND PERMEABILITY: Well drained; high surface runoff; moderate permeability; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Chesebro soils are used for livestock grazing and wildlife habitat. The historic plant community is mountain big sagebrush, snowberry, antelope bitterbrush, Idaho fescue, and bluebunch wheatgrass.

DISTRIBUTION AND EXTENT: South-central Oregon. These soils are not extensive with about 4,900 acres of the series mapped to date. MLRA 23.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.

SERIES ESTABLISHED: Lake County (Northern Part), Oregon, 2006.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 61 cm (A1, A2, and AB horizons).
Argillic horizon - The zone from 64 to 152 (Bt1 and Bt2 horizons).
Vitrandic intergrade feature - The zone from the soil surface to 30 inches (A1, A2, and AB horizons and part of the Bt1 horizon).
Particle-size control section and ashy substitute class with glassy mineralogy - The zone from 64 to 114 cm (Bt1 horizon and part of the Bt2 horizon).

ADDITIONAL DATA: The typical pedon at the series type location is reference sampled for the Soil Survey Laboratory (SSL), Lincoln, NE, as soil survey sample number S02OR-037-001 (pedon # 03N0328). Selected data including optical glass counts are available. Volcanic glass content has also been determined locally in the Reno MO by optical grain counts using a polarizing petrographic microscope.

National Cooperative Soil Survey
U.S.A.