LOCATION MILCAN OR

Established Series
Rev. JSC-AON-TDT-JVC-JBF
04/2011

MILCAN SERIES

The Milcan series consists of moderately deep to a duripan, somewhat excessively drained soils that formed in volcanic ash and alluvium derived from volcanic rocks. Milcan soils are on lava plains. Slopes are 0 to 5 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 Durixerolls

TYPICAL PEDON: Milcan gravelly ashy sandy loam--on a lava plain sloping 1 percent under mountain big sagebrush at an elevation of 1,442 meters--rangeland. (Colors are for dry soil unless otherwise noted.)

A1--0 to 20 cm; grayish brown (10YR 5/2) gravelly ashy sandy loam, very dark grayish brown (10YR 3/2) moist; massive; soft, very friable, nonsticky and nonplastic; many roots; many irregular pores; about 25 percent gravel; neutral (pH 7.3); clear smooth boundary. (5 to 25 cm thick)

A2--20 to 43 cm; brown (10YR 5/3) ashy loamy sand, dark brown (10YR 3/3) moist; massive; soft, very friable, nonsticky and nonplastic; many roots; many irregular pores; about 5 percent gravel; slightly alkaline (pH 7.5); gradual smooth boundary. (15 to 30 cm thick)

AB--43 to 61 cm; pale brown (10YR 6/3) ashy sandy loam, dark brown (10YR 3/3) moist; massive; soft, very friable, nonsticky and nonplastic; common roots; many irregular pores; about 5 percent gravel; slightly alkaline (pH 7.4); clear smooth boundary. (0 to 25 cm thick)

Bq--61 to 97 cm; pale brown (10YR 6/3) ashy sandy loam, dark brown (10YR 3/3) moist; massive; slightly hard, friable, slightly sticky and nonplastic; few roots; many irregular pores; about 10 percent gravel; many durinodes and pockets of firm, brittle soil material; slightly alkaline (pH 7.4); abrupt wavy boundary. (13 to 60 cm thick)

2Bkqm--97 to 152 cm; pale brown (10YR 6/3) cemented material, dark brown (10YR 3/3) moist; platy structure; indurated by secondary silica; slightly effervescent.

TYPE LOCATION: Deschutes County, Oregon; between Pine Mountain and Pine Ridge in the NE1/4 of the NE1/4 of the SW1/4 of section 34, T. 20 S., R. 16 E.; USGS Millican SE 7.5 minute topographic quadrangle; latitude 43 degrees 47 minutes 32 seconds N and longitude 120 degrees 47 minutes 54 seconds W; NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry, moist in winter and spring; aridic moisture regime that borders on xeric.
Mean annual soil temperature: 7 to 8 degrees C.
Mollic epipedon thickness: 25 to 50 cm.
Depth to duripan: 50 to 100 cm.
Depth to bedrock: More than 150 cm.
Vitrandic intergrade properties: Volcanic glass content: 30 to 60 percent in coarse silt through fine sand fractions; phosphate retention is 15 to 25 percent; acid oxalate extractable aluminum plus one-half the acid oxalate extractable iron is 0.3 to 0.6 percent.

Particle-size control section - Clay content: 5 to 15 percent.
Rock fragments: 0 to 25 percent, mainly pebbles. Lithology of fragments are volcanic rocks such as basalt.

A1 horizon
Value: 4 or 5 dry, 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 1 or 2 percent.

A2 and AB horizons
Value: 4 through 7 dry, 3 or 4 moist.
Chroma: 2 or 3, dry or moist.
Texture: Ashy loamy sand, gravelly ashy loamy sand, ashy sandy loam, or gravelly ashy sandy loam.
Rock fragments: 0 to 25 percent gravel.
Reaction: Neutral or slightly alkaline.
Organic matter content: 0.5 to 2 percent.

Bq horizon
Texture: Ashy sandy loam, gravelly ashy sandy loam, ashy fine sandy loam, ashy loamy fine sand, or gravelly ashy loamy fine sand.
Rock fragments: 0 to 25 percent gravel
Reaction: Neutral through moderately alkaline.

COMPETING SERIES: These are the Greenmountain, Meld, and Sliptrack series. Greenmountain, Meld, and Sliptrack soils have argillic horizons.

GEOGRAPHIC SETTING: Milcan soils are on lava plains. These soils formed in volcanic ash and alluvium derived from volcanic rocks. The volcanic ash deposits are from ancestral Mt. Mazama (Crater Lake) and Newberry Crater. Slopes are 0 to 5 percent. Elevations range from 1,310 to 1,525 meters. The climate is semiarid and characterized by cold, moist winters and warm, dry summers. The mean annual precipitation is 200 to 300 mm. The mean annual temperature is 6 to 7 degrees C. The frost-free period is 50 to 90 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Borobey and Stookmoor soils. Borobey soils are very deep and have a hard, firm brittle layer within 100 cm of the soil surface. Stookmoor soils are moderately deep to lithic contacts and have a hard, firm brittle layer above the bedrock contact.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat excessively drained; high surface runoff; high saturated hydraulic conductivity.

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

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 43 cm (A1 and A2 horizons).
Durinodes - The zone from 61 to 97 cm (Bq horizon).
Vitrandic intergrade feature - The zone from the soil surface to 76 cm (A1, A2, and AB horizons and part of the Bq horizon).
Duripan - The zone from 97 to 152 cm (2Bkqm horizon).
Particle-size control section and ashy substitute class with glassy mineralogy - The zone from 25 to 97 cm (AB and Bq horizons and part of the A2 horizon).

ADDITIONAL DATA: Partial laboratory data are available for this pedon from the Soil Survey Laboratory, Lincoln, NE, as soil survey sample number S89OR-017-002 (pedon # 89P0789). Soil characterization data on two pedons (S79OR-017-6 and S79OR-017-7) reported in Oregon State University Soils Laboratory.

National Cooperative Soil Survey
U.S.A.