LOCATION NORCROSS                OR

Established Series
Rev. CWL-JVC
05/2011

NORCROSS SERIES

The Norcross series consists of shallow to a duripan, well drained soils that formed in volcanic ash over residuum derived from basalt. Norcross soils are on lava plateaus. Slopes are 0 to 10 percent. The mean annual precipitation is about 400 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Clayey, smectitic, frigid, shallow Vitrandic Durixerolls

TYPICAL PEDON: Norcross very cobbly ashy loam--on a 1 percent slope at an elevation of 1,508 meters--rangeland. (Colors are for dry soil unless otherwise noted. The soil was dry throughout when it was described on November 5, 1997.)

A1--0 to 8 cm; light brown (7.5YR 6/3) very cobbly ashy loam, dark brown (7.5YR 3/3) moist; weak thick platy structure parting to moderate thin platy; hard, friable, slightly sticky and slightly plastic; many very fine and few fine roots; common fine and common medium vesicular pores; 15 percent gravel, 20 percent cobbles, and 5 percent stones; neutral (pH 7.2); abrupt smooth boundary. (5 or 8 cm thick)

A2--8 to 15 cm; brown (7.5YR 5/3) cobbly ashy loam, dark brown (7.5YR 3/3) moist; weak thin platy structure parting to moderate medium granular; soft, very friable, slightly sticky and slightly plastic; common very fine, common fine, and few medium roots; common fine and common medium tubular pores; 15 percent gravel and 12 percent cobbles; neutral (pH 7.2); clear smooth boundary. (0 to 13 cm thick)

Bt1--15 to 25 cm; brown (7.5YR 5/3) cobbly ashy clay loam, dark brown (7.5YR 3/4) moist; moderate medium subangular blocky structure parting to weak fine angular blocky; slightly hard, firm, moderately sticky and moderately plastic; common very fine, few fine, and few medium roots; common fine and common medium tubular pores; common faint clay films on faces of peds; 5 percent gravel and 15 percent cobbles; slightly alkaline (pH 7.4); abrupt smooth boundary. (8 to 20 cm thick)

Bt2--25 to 46 cm; brown (7.5YR 5/4) clay, dark brown (7.5YR 3/4) moist; strong medium prismatic structure parting to strong medium angular blocky; very hard, very firm, moderately sticky and very plastic; few very fine and few fine roots; few fine tubular pores; few pressure faces; common distinct clay films on faces of peds; slightly alkaline (pH 7.5); clear smooth boundary. (8 to 25 cm thick)

Bt3--46 to 50 cm; light brown (7.5YR 6/3) clay, brown (7.5YR 4/4) moist; moderate medium prismatic structure parting to moderate medium and strong fine angular blocky; hard, firm, moderately sticky and very plastic; few very fine and few fine roots; few very fine and few fine tubular pores; common pressure faces; common distinct and few faint clay films on faces of peds; slightly alkaline (pH 7.6); abrupt smooth boundary. (0 to 18 cm thick)

Bqm--50 to 79 cm; pink (7.5YR 7/4) cemented material, strong brown (7.5YR 4/6) moist; strong thick platy structure; very rigid; indurated by secondary silica; widely spaced fractures in the upper inch; thin laminar caps of opal on top of peds; slightly alkaline (pH 7.8); abrupt wavy boundary. (5 to 66 cm thick)

R--79 cm; hard vesicular basalt.

TYPE LOCATION: Klamath County, Oregon; about 0.25 mile west of the CCC road on the access road to the Barnes Valley Creek boat launch, 75 feet north of the road and close to the range trend plot stake; approximately 1,000 feet north and 150 feet west of the southeast corner of section 21, T. 39 S., R. 14 E.; USGS Gerber Reservoir 7.5 minute topographic quadrangle; latitude 42 degrees 10 minutes 6 seconds N and longitude 121 degrees 3 minutes 27 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: 7 to 8 degrees C.
Mean summer soil temperature: 15 to 16 degrees C.
Mollic epipedon thickness: 18 to 38 cm; includes the Bt1 horizon, and in some pedons also includes the Bt2 horizon, when the upper 18 cm of soil is mixed.
Argillic horizon thickness: 18 to 40 cm.
Depth to base of argillic horizon 30 to 50 cm.
Depth to duripan: 30 to 50 cm.
Duripan thickness: 5 to 66 cm.
Depth to bedrock: 46 to 117 cm to a lithic contact.
Vitrandic intergrade properties: Occurs in horizons from the soil surface to at least 18 cm in depth within horizons having clay content of less than about 40 percent.
Reaction: Neutral or slightly alkaline.
Other features: Some pedons have Btq horizons.

Particle-size control section - Clay content: 45 to 55 percent.
Rock fragments: 0 to 10 percent, mainly gravel and cobbles. Lithology of fragments is dominantly basalt.

A1 horizon
Hue: 10YR or 7.5YR.
Value: 4 through 6 dry, 2 or 3 moist; A dry value of 6 is only in thin subhorizons in some pedons and the upper 18 cm when mixed has a dry value of 5.
Chroma: 2 or 3, dry or moist.
Organic matter content: 2 to 4 percent.
Volcanic glass content: 15 to 30 percent in coarse silt through fine sand fractions.
Oxalate extractable aluminum plus one-half oxalate iron: 0.2 to 0.4 percent.

A2 horizon (when present)
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 2 or 3 moist; A dry value of 6 is only in thin subhorizons in some pedons and the upper 18 cm when mixed has a dry value of 5.
Chroma: 2 or 3, dry or moist.
Texture: Cobbly ashy loam, cobbly ashy clay loam, very cobbly ashy loam, or very cobbly ashy clay loam.
Clay content: 22 to 36 percent.
Rock fragments: 20 to 45 percent.
Organic matter content: 1 to 4 percent.
Volcanic glass content: 15 to 30 percent in coarse silt through fine sand fractions.
Oxalate extractable aluminum plus one-half oxalate iron: 0.2 to 0.4 percent.

Bt1 or 2Bt1 horizon
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 through 4, dry or moist.
Texture: Ashy clay loam, cobbly ashy clay loam, clay, or cobbly clay.
Clay content: 36 to 46 percent.
Rock fragments: 0 to 25 percent.
Organic matter content: 0.2 to 3 percent.
Volcanic glass content: 10 to 25 percent in coarse silt through fine sand fractions.
Oxalate extractable aluminum plus one-half oxalate iron: 0.2 to 0.4 percent.

Bt2 or 2Bt2 horizon
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Clay or cobbly clay.
Clay content: 40 to 55 percent.
Rock fragments: 0 to 25 percent.
Organic matter content: 1 to 3 percent.
Other features: Some pedons have texture of ashy clay loam in thin subhorizons.

Bt3 or 2Bt3 horizon (when present)
Value: 5 through 7 dry, 3 or 4 moist.
Chroma: 3 through 6, dry or moist.
Clay content: 45 to 60 percent.
Rock fragments: 0 to 10 percent, mainly cobbles.


Bqm horizon
Value: 7 or 8 dry, 4 through 6 moist.
Chroma: 3 through 6, dry or moist.
Cementation: Indurated or very strongly cemented.

COMPETING SERIES: This is the Dunres series. Dunres soils average 35 to 45 clay in the particle-size control section and have 60 to 80 percent volcanic glass in the mollic epipedon.

GEOGRAPHIC SETTING: Norcross soils are on lava plateaus. They typically occur on summit positions. These soils formed in volcanic ash over residuum derived from basalt. Slopes are 0 to 15 percent. Elevations range from 1,310 to 1,710 meters. The climate is subhumid and characterized by cold, moist winters and warm, dry summers. The mean annual precipitation is 300 to 500 mm. The mean annual temperature is 6 to 7 degrees C, The frost-free period is 50 to 80 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Casebeer, Devaul, Dranket, and Mound soils. Casebeer soils lack a mollic epipedon. Devaul, Dracket and Mound soils are deeper than 50 cm..

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

USE AND VEGETATION: Norcross soils are used for livestock grazing, wildlife habitat, and recreation. The native vegetation is Idaho fescue, Sandberg's bluegrass, bluebunch wheatgrass, low sagebrush, and western juniper.

DISTRIBUTION AND EXTENT: South-central Oregon. These soils are moderately extensive. MLRA 21.

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

SERIES ESTABLISHED: Lake County (Northern Part), Oregon, 2006. The series was proposed as part of the Gerber Block of the Fremont National Forest Area, Klamath County, Oregon in 1998. The name is from a spring in the Fremont NF survey area.

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 and part of the Bt1 horizon).
Argillic horizon - The zone from 15 to 50 cm (Bt1, Bt2, and Bt3 horizons).
Vitrandic intergrade feature - The zone from the soil surface to 25 cm (A1, A2, and Bt1 horizons).
Duripan - The zone from 50 to 79 cm (Bqm horizon).
Lithic contact - The boundary at 79 cm to underlying hard bedrock (R layer).
Particle-size control section - The zone from 15 to 50 cm (Bt1, Bt2, and Bt3 horizons).

ADDITIONAL DATA: Volcanic glass content determined locally by optical grain counts using a polarizing petrographic microscope. The typical pedon for the series from the Gerber Block of the Fremont National Area and one pedon from Lake County, Oregon, Northern Part were sampled and glass was counted in upper horizons. Oxalate extractable aluminum plus one-half oxalate extractable iron values are estimated.

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National Cooperative Soil Survey
U.S.A.