LOCATION GOODTACK                OR

Established Series
Rev. CWL-MPK-JVC-JBF
03/2011

GOODTACK SERIES

The Goodtack series consists of shallow to a duripan, well drained soils that formed in volcanic ash over residuum derived from basalt or tuff-breccia. Goodtack soils are on lava plateaus and hills. Slopes are 0 to 20 percent. The mean annual precipitation is about 250 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Ashy, glassy, frigid, shallow Vitritorrandic Durixerolls

TYPICAL PEDON: Goodtack ashy very fine sandy loam--on a plateau sloping 8 percent to the west at an elevation of 1,404 meters--rangeland. (Colors are for dry soil unless otherwise noted. The soil was dry throughout when described on October 17, 2002.)

A1--0 to 8 cm; grayish brown (10YR 5/2) ashy very fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium platy structure parting to weak coarse, medium and fine granular; soft, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine interstitial pores; slightly alkaline (pH 7.6); clear smooth boundary. (5 to 15 cm thick)

A2--8 to 18 cm; brown (10YR 5/3) ashy fine sandy loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine and common fine roots; many very fine interstitial and common very fine tubular pores; slightly alkaline (pH 7.6); clear smooth boundary. (8 to 18 cm thick)

Bt--18 to 33 cm; pale brown (10YR 6/3) ashy fine sandy loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, common fine, and common medium roots; common very fine tubular pores; common faint brown (10YR 5/3) clay films on faces of peds; slightly alkaline (pH 7.6); clear smooth boundary. (10 to 33 cm thick)

Btq--33 to 48 cm; pale brown (10YR 6/3) ashy sandy clay loam, dark grayish brown (10YR 4/2) moist; moderate fine and medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; common very fine, few fine, and few medium roots; common very fine tubular pores; common faint brown (10YR 5/3) clay films on faces of peds; common faint silica coats on faces of peds; 5 percent gravel-size detached fragments of duripan; slightly alkaline (pH 7.8); clear smooth boundary. (0 to 15 cm thick)

Bqkm--48 to 117 cm; very pale brown (10YR 8/2) cemented material; strong thick platy structure parting to strong medium platy; very rigid; indurated by secondary silica; thin laminar caps of opaline silica on top of horizon; strongly effervescent; secondary carbonates segregated as coats on faces of peds; abrupt smooth boundary. (18 to 70 cm thick)

R--117 cm; unweathered basalt.

TYPE LOCATION: Lake County, Oregon; about 1 mile north of the northeastern corner of the Lost Forest Research Natural Area on road 6121-0-00; approximately 750 feet north and 1,500 feet east of the southwest corner of section 12, T. 25 S., R. 20 E.; USGS Moonlight Butte 7.5 minute topographic quadrangle; latitude 43 degrees, 24 minutes, 56 seconds N and longitude 120 degrees, 16 minutes, 17 seconds W; NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter and spring, dry in summer and fall; aridic moisture regime that borders on xeric.
Mean annual soil temperature: 7 to 8 degrees C.
Mollic horizon thickness: 18 to 46 cm; includes the Bt horizon in some pedons.
Depth to duripan: 40 to 50 cm.
Depth to bedrock: 50 to 112 cm to a lithic contact.

Particle-size control section - Clay content: 18 to 26 percent.
Rock fragments: averages 0 to 10 percent, mainly pebbles. Lithology of fragments are basalt, tuff-breccia, or moderately cemented to indurated duripan fragments.
Volcanic glass content: 30 to 75 percent in coarse silt through fine sand fractions.

A1 horizon
Value: 5 or 6 dry, 3 or 4 moist; Averages 5 dry and 3 moist when mixed.
Chroma: 2 or 3, dry or moist.
Organic matter content: 1 to 3 percent.
Reaction: Neutral or slightly alkaline.

A2 horizon
Texture: Ashy fine sandy loam or ashy sandy loam.
Clay content: 8 to 14 percent.
Rock fragments: 0 to 10 percent.
Organic matter content: 1 to 3 percent.

Bt horizon
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 or 3, dry or moist.
Texture: Ashy sandy clay loam, ashy fine sandy loam, or ashy loam.
Clay content: 18 to 26 percent.
Rock fragments: 0 to 10 percent.
Pararock fragments: 0 to 10 percent.

Btq horizon (when present)
Value: 5 or 6 dry.
Chroma: 2 or 3, dry or moist.
Bqkm horizon
Cementation: Moderately cemented to indurated by secondary silica.

COMPETING SERIES: This is the Senra series. Senra soils have 27 to 35 percent clay in the particle-size control section.

GEOGRAPHIC SETTING: Goodtack soils are on lava plateaus and hills. These soils formed in volcanic ash over residuum derived from basalt or tuff-breccia. Slopes are 0 to 20 percent. Elevations range from 1,310 to 1,585 meters. The climate is arid with cold, moist winters and warm, dry summers. The mean annual precipitation is 200 to 330 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 Borobey and Lastcall soils and the competing Senra soil. Borobey soils are very deep, do not have argillic horizons, and do not have duripans. Lastcall soils are moderately deep to lithic contacts and do not have duripans.

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

USE AND VEGETATION: Goodtack soils are used for livestock grazing. The native vegetation is basin big sagebrush, mountain big sagebrush, Idaho fescue, Thurber's needlegrass, and bluebunch wheatgrass. Some sites have scattered western juniper.

DISTRIBUTION AND EXTENT: South-central Oregon. These soils are extensive with about 127,000 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. The name is coined.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 18 cm (A1 and A2 horizons).
Argillic horizon - The zone from 18 to 48 cm (Bt and Btq horizons).
Vitrandic intergrade feature - The zone from the soil surface to 48 cm (A1, A2, Bt, and Btq horizons).
Duripan - The zone from 48 to 117 cm (Bqkm horizon).
Lithic contact - The boundary at 117 cm to underlying hard bedrock (R layer).
Particle-size control section and ashy substitute class with glassy mineralogy - The zone from 18 to 51 cm (Bt and Btq horizons).

A revision in January 2003 updated the taxonomic class from Ashy, glassy, frigid Vitritorrandic Durixerolls, moved the type location to a more representative area, and changed the series concept from a moderately deep to a shallow soil.

---

National Cooperative Soil Survey
U.S.A.