LOCATION BOROBEY OR

Established Series
Rev. JSC-TDT-JVC-JBF
12/2010

BOROBEY SERIES

The Borobey series consists of very deep, somewhat excessively drained soils that formed in pumiceous volcanic ash over alluvium derived from volcanic rocks. Borobey soils are on valley floors and lake terraces. Slopes are 0 to 15 percent. The mean annual precipitation is about 280 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Ashy, glassy, frigid Vitritorrandic Haploxerolls

TYPICAL PEDON: Borobey ashy sandy loam--on a 2 percent slope under sagebrush steppe at an elevation of 1,310 meters--rangeland. (Colors are for dry soil unless otherwise noted.)

A--0 to 10 cm; grayish brown (10YR 5/2) ashy sandy loam, very dark grayish brown (10YR 3/2) moist; weak thick platy structure; soft, very friable, slightly sticky and nonplastic; many very fine roots; many very fine interstitial pores; neutral; clear smooth boundary. (5 to 25 cm thick)

AB--10 to 53 cm; brown (10YR 5/3) ashy sandy loam, dark brown (10YR 3/3) moist; massive; soft, very friable, slightly sticky and nonplastic; common very fine roots; many very fine interstitial pores; neutral; clear wavy boundary. (13 to 76 cm thick)

Bq--53 to 130 cm; pale brown (10YR 6/3) ashy sandy loam, dark yellowish brown (10YR 3/4) moist; moderate fine subangular blocky structure; hard, firm and brittle, slightly sticky and slightly plastic; few very fine roots; common very fine tubular pores; neutral; abrupt smooth boundary. (23 to 100 cm thick).

2Bwb--130 to 152 cm; pale brown (10YR 6/3) clay loam, dark yellowish brown (10YR 3/4) moist; moderate fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine roots; common very fine tubular pores; neutral.

TYPE LOCATION: Deschutes County, Oregon; between Millican and Brothers about 900 feet south of U.S. Highway 20; in the northwest quarter of the northwest quarter of the northwest quarter of section 12, T. 20 S., R. 16 E.; USGS Millican SE 7.5 minute topographic quadrangle; latitude 43 degrees 51 minutes 12 seconds N and longitude 120 degrees 45 minutes 59 seconds W; NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter and spring but are dry in the moisture control section about 115 to 120 days consecutively in the four-month period following the summer solstice; aridic soil moisture regime that borders on xeric.
Mean annual soil temperature: 7 to 8 degrees C.
Mollic epipedon thickness: 25 to 43 cm.
Depth to firm, brittle horizons: 25 to 100 cm.
Depth to buried horizons: 100 to more than 150 cm.
Depth to bedrock or duripan: more than 150 cm.
Vitrandic intergrade properties: Volcanic glass content: 40 to 60 percent in coarse silt through fine sand fractions; Phosphate retention: 15 to 25 percent; Oxalate extractable aluminum plus one-half the oxalate extractable iron: 0.3 to 0.6 percent.

Particle-size control section - Clay content: Averages 5 to 15 percent.
Rock fragments: 0 to 30 percent, mainly gravel. Lithology of fragments are volcanic rocks such as basalt.

A horizon
Chroma: 2 or 3, dry or moist.
Organic matter content: 0.5 to 3 percent.
Reaction: Neutral or slightly alkaline.
Other features: Some pedons have thin subhorizons with dry value of 6, but are value 5 when the upper 18 cm of soil is mixed. A and AB horizons

AB horizon
Chroma: 2 or 3, dry or moist.
Texture: Ashy sandy loam, gravelly ashy sandy loam, gravelly ashy loamy sand, gravelly ashy sandy loam, ashy very fine sandy loam, or ashy fine sandy loam; some pedons have thin A horizons with texture of ashy loamy sand.
Rock fragments: 0 to 25 percent gravel, 0 to 5 percent cobbles.
Organic matter content: 0.5 to 3 percent.
Reaction: Neutral or slightly alkaline.

Bq horizon
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 through 4, dry or moist.
Texture: Ashy sandy loam, gravelly ashy sandy loam, ashy loamy fine sand, or ashy fine sandy loam.
Clay content: 4 to 18 percent.
Sand content: 55 to 80 percent.
Rock fragments: 0 to 25 percent gravel, 0 to 5 percent cobbles.
Consistence: Firm and brittle when moist.
Reaction: Neutral through moderately alkaline.
Salinity (EC): 0 to 2 mmhos/cm.
Other features: Some pedons have two Bq horizons.

2Bwb horizon (when present)
Texture: Loam or clay loam.
Clay content: 15 to 30 percent.
Reaction: Neutral through moderately alkaline.
Salinity (EC): 0 to 2 mmhos/cm.
C horizon (when present)
Value: 4 through 6 dry, 3 or 4 moist.
Chroma: 2 through 4, dry or moist.
Texture: Ashy loamy sand, ashy sandy loam, gravelly ashy loamy sand, very gravelly ashy loamy coarse sand, or very gravelly ashy sandy loam.
Clay content: 3 to 18 percent.
Rock fragments: 0 to 50 percent gravel.
Reaction: Neutral through moderately alkaline.
Salinity (EC): 0 to 2 mmhos/cm.

COMPETING SERIES: These are the Boltz, Bonnick, Emamount, Embal, Frentera, Gardone, Oatmanflat, Picturerock, Stookmoor, Tuffcabin, and Wegert series.

Boltz soils are moderately deep to paralithic contacts. Bonnick and Gardone soils do not have firm, brittle horizons over 6 inches thick within 40 inches of the soil surface. Emamount soils do not have Bq horizons that are brittle, have 18 to 27 percent clay in the particle-size control section, and have endosaturation between 150 and 180 cm from the soil surface. Embal soils have mollic epipedons 50 to 90 cm thick and have irregular decrease in organic carbon with depth. Frentera, Stookmoor, and Wegert soils are moderately deep to lithic contacts. Oatmanflat and Tuffcabin soils have buried duripans within 150 cm of the soil surface. Picturerock soils do not have firm, brittle horizons within 100 cm of the soil surface and have horizons with identifiable secondary carbonates.

GEOGRAPHIC SETTING: Borobey soils are on valley floors, lake terraces, and depressions on lava plateaus. These soils formed in pumiceous volcanic ash over alluvium derived from volcanic rocks. Slopes are 0 to 15 percent. Elevations range from 1,280 to 1,620 meters. The climate is semiarid and characterized by cold, moist winters and warm, dry summers. The mean annual precipitation is 8 to 12 inches. The mean annual temperature is 6 to 7 degrees C., mean January temperature is -3 to -2 degrees C., and the mean July temperature is 15 to 16 degrees C. The frost-free period is 50 to 90 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Gardone and Stookmoor soils.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; low surface runoff; moderately rapid permeability; moderately high saturated hydraulic conductivity in the surface and subsurface horizons, moderately slow permeability in the firm, brittle horizon, and moderate to moderately slow permeability in the buried horizon.

USE AND VEGETATION: Borobey soils are used for livestock grazing and wildlife habitat. Potential native vegetation is mountain big sagebrush, Idaho fescue, Thurber's needlegrass, western needlegrass, and Ross sedge.

DISTRIBUTION AND EXTENT: Central Oregon. These soils are moderately extensive. MLRA 23.

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

SERIES ESTABLISHED: Deschutes County (Upper Deschutes River Area), Oregon, 1992.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 38 cm (A horizon and part of the AB horizon). Dark Munsell colors extend to 53 cm, but organic matter content is less than one percent below 38 cm.
Duric feature - The zone from 53 to 130 cm (Bq horizon).
Vitrandic intergrade feature - The zone from the soil surface to 76 cm (A and AB horizons and part of the Bq horizon).
Major lithologic discontinuity - The abrupt change to non-ashy material at 130 cm.
Buried horizon - The zone from 130 to 150 cm (2Bwb horizon).
Particle-size control section and ashy substitute class with glassy mineralogy - The zone from 25 to 100 cm (parts of the AB and Bq horizons).

This series was revised in 1999 to eliminate the Deep depth class. The phase of Borobey which is deep to a duripan from the Upper Deschutes River Area soil survey needs correlation to another series.

ADDITIONAL DATA: The typical pedon at the series type location was reference sampled for the Soil Survey Laboratory (SSL), Lincoln, NE, as soil survey sample number S89OR-017-001. Data for optical grain counts of volcanic glass content, oxalate extractions for iron, aluminum, and silicon, and phosphate retention are available for the first three horizons of the typical pedon.

National Cooperative Soil Survey
U.S.A.