LOCATION LASTCALL                OR

Established Series
Rev. SJS-JVC-JBF
04/2011

LASTCALL SERIES

The Lastcall series consists of moderately deep, well drained soils that formed in volcanic ash and residuum derived from basalt. Lastcall soils are on lava plateaus. 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 Argixerolls

TYPICAL PEDON: Lastcall ashy sandy loam--on the summit of a plateau sloping 2 percent to the southeast at an elevation of 1,468 meters--rangeland. (Colors are for dry soil unless otherwise noted. When described on June 9, 1999, the soil was dry throughout.)

A1--0 to 5 cm; brown (10YR 5/3) ashy sandy loam, dark brown (10YR 3/3) moist; moderate medium platy structure parting to weak very fine granular; slightly hard, very friable, nonsticky and nonplastic; few very fine and common fine roots; common very fine dendritic tubular pores; 5 percent gravel; slightly alkaline (pH 7.4); clear smooth boundary. (5 to 15 cm thick)

A2--5 to 18 cm; brown (10YR 5/3) ashy sandy loam, dark brown (10YR 3/3) moist; moderate medium granular structure parting to weak very fine granular; slightly hard, very friable, nonsticky and nonplastic; common very fine and few fine roots; common very fine dendritic tubular pores; 5 percent gravel; slightly alkaline (pH 7.6); clear smooth boundary. (13 to 33 cm thick)

BA--18 to 33 cm; brown (10YR 5/3) ashy sandy loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure parting to moderate fine subangular blocky; slightly hard, friable, nonsticky and nonplastic; few very fine and fine roots; common very fine dendritic tubular pores; 5 percent gravel; slightly alkaline (pH 7.6); clear smooth boundary. (0 to 15 cm thick)

Btq--33 to 53 cm; pale brown (10YR 6/3) cobbly ashy sandy clay loam, dark yellowish brown (10YR 3/4) moist; moderate medium subangular blocky structure parting to moderate fine subangular blocky; moderately hard, firm, moderately sticky and moderately plastic; few very fine roots; common very fine dendritic tubular pores; 20 percent very weakly cemented durinodes; common faint clay films on faces of peds and lining pores; 5 percent gravel and 10 percent cobbles; slightly alkaline (pH 7.6); clear smooth boundary. (0 to 36 cm thick)

Bt--53 to 79 cm; pale brown (10YR 6/3) cobbly ashy sandy clay loam, dark yellowish brown (10YR 3/4) moist; moderate medium and fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine roots; common very fine dendritic tubular pores; common distinct clay films on faces of peds and lining pores; 10 percent gravel and 10 percent cobbles; slightly alkaline (pH 7.8); clear smooth boundary. (10 to 46 cm thick)

R--79 cm; hard, fractured basalt; thin (<2 mm) silica coats lining fractures.

TYPE LOCATION: Lake County, Oregon; about 3 miles south-southeast of Saddle Butte and west of the North Fork of Peters Creek; approximately 1,425 feet north and 50 feet west of the southeast corner of section 35, T. 23 S., R. 18 E.; USGS Last Chance Lake 7.5 minute topographic quadrangle; latitude 43 degrees 31 minutes 57 seconds N and longitude 120 degrees 30 minutes 58 seconds W; NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter and spring; dry in summer from July through October; aridic moisture regime that borders on xeric.
Mean annual soil temperature: 7 to 8 degrees C.
Mollic epipedon thickness: 18 to 38 cm.
Depth to base of argillic horizon: 66 to 86 cm.
Depth to bedrock: 66 to 86 cm to a lithic contact.
Volcanic glass content: 35 to 75 percent in the very fine sand and fine sand fractions.

Particle-size control section - Clay content: 20 to 35 percent.
Rock fragments: 10 to 20 percent, mainly cobbles. Lithology of fragments are basalt.

A1 horizon
Value: 3 or 4 moist.
Chroma: 2 or 3, dry or moist.
Consistence: Slightly hard or hard dry, very friable or friable moist.
Organic matter content: 1 to 3 percent.

A2 horizon
Value: 3 or 4 moist.
Chroma: 2 or 3, dry or moist.
Texture: Ashy sandy loam or ashy loamy sand.
Clay content: 5 to 15 percent.
Rock fragments: 5 to 10 percent, mainly gravel.
Consistence: Slightly hard or hard dry, very friable or friable moist.
Organic matter content: 1 to 3 percent.

BA horizon (when present)
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 or 3, dry or moist.
Texture: Ashy sandy loam or ashy loamy sand.
Clay content: 5 to 15 percent.
Rock fragments: 5 to 10 percent, mainly gravel.
Organic matter content: 1 or 2 percent.

Btq horizon (when present)
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 through 4, dry or moist.
Texture: Cobbly ashy sandy clay loam or ashy sandy clay loam.
Clay content: 20 to 28 percent.
Rock fragments: 10 to 20 percent.
Durinodes: 15 to 20 percent very weakly cemented or weakly cemented.

Bt horizon
Value 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Cobbly ashy sandy clay loam or ashy sandy clay loam.
Clay content: 20 to 34 percent.
Rock fragments: 10 to 25 percent.
Other features: Some pedons have texture of ashy sandy loam.

COMPETING SERIES: These are the Ashdos, Ashtre, Millenium, and Stauffer series.

Ashdos and Ashtre soils are moderately deep to paralithic contacts. Millenium and Stauffer soils are very deep.

GEOGRAPHIC SETTING: Lastcall soils are on lava plateaus. They formed in volcanic ash and residuum derived from basalt. Slopes are 0 to 15 percent. Elevations range from 1,250 to 1,585 meters. The mean annual precipitation is 250 to 300 mm, the mean annual temperature is 6 to 7 degrees C, and the frost-free period is 50 to 80 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Goodtack, Kunceider, and Senra soils. Goodtack and Senra soils are shallow to duripans. Kunceider soils are ashy-skeletal, shallow to lithic contacts, and do not have argillic horizons.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; very high surface runoff; moderately high or high saturated hydraulic conductivity.

USE AND VEGETATION: Lastcall soils are used for livestock grazing and wildlife habitat. The present vegetation is low sagebrush, Idaho fescue, Thurber's needlegrass, and western juniper.

DISTRIBUTION AND EXTENT: South-central Oregon. These soils are moderately extensive. MLRA 23.

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

SERIES ESTABLISHED: Lake County (Northern Part), Oregon, 2006. The name is coined.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 33 cm (A1, A2, and BA horizons).
Argillic horizon - The zone from 33 to 79 cm (Btq and Bt horizons).
Vitrandic intergrade feature - The zone from the soil surface to 79 cm (A1, A2, BA, Btq, and Bt horizons).
Durinodes - The zone from 33 to 53 cm (Btq horizon).
Lithic contact - The boundary at 79 cm to underlying hard bedrock (R layer).
Particle-size control section and ashy substitute class with glassy mineralogy - The zone from 33 to 79 cm (Btq and Bt horizons).

ADDITIONAL DATA: Volcanic glass content determined locally by optical grain counts using a polarizing petrographic microscope.

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National Cooperative Soil Survey
U.S.A.