LOCATION TALLBOY ORTentative Series
TAXONOMIC CLASS: Fine, smectitic, frigid Pachic Ultic Argixerolls
TYPICAL PEDON: Tallboy gravelly loam--on a 5 percent slope at an elevation of 4,925 feet--forestland. (Colors are for dry soil unless otherwise noted. The soil was moist throughout when it was described on July 15, 1998.) The soil surface is covered by a two inch layer of undecomposed to slightly decomposed pine needles.
A1--0 to 2 inches; dark grayish brown (10YR 4/2) gravelly loam, very dark brown (10YR 2/2) moist; strong thin platy structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and common fine roots; common fine and common medium interstitial and tubular pores; 10 percent pebbles, 5 percent cobbles, and 2 percent stones; slightly acid (pH 6.5); abrupt smooth boundary. (2 to 4 inches thick)
A2--2 to 7 inches; grayish brown (10YR 5/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; strong thick platy structure parting to strong medium granular; slightly hard, friable, slightly sticky and slightly plastic; few very fine, common fine, common medium, and few coarse roots; common fine and common medium interstitial and tubular pores; 10 percent pebbles and 5 percent cobbles; neutral (pH 6.6); abrupt smooth boundary. (4 to 15 inches thick)
A3--7 to 21 inches; gray (10YR 5/1) loam, very dark gray (10YR 3/1) moist; moderate medium subangular blocky structure; soft, friable, slightly sticky and slightly plastic; few very fine, common fine, common medium, and few coarse roots; common fine and common medium tubular pores; 10 percent pebbles; neutral (pH 6.6); clear smooth boundary. (0 to 15 inches thick)
Bt1--21 to 34 inches; brown (10YR 5/3) clay loam, dark brown (10YR 3/3) moist; strong medium subangular blocky structure; slightly hard, firm, moderately sticky and moderately plastic; few very fine, common fine, common medium, and few coarse roots; common fine and common medium tubular pores; common faint and few distinct clay films on faces of peds; 10 percent pebbles; neutral (pH 6.6); gradual smooth boundary. (6 to 14 inches thick)
2Bt2--34 to 46 inches; light brown (7.5YR 6/3) very cobbly clay, brown (7.5YR 4/3) moist; strong medium subangular blocky structure parting to moderate fine angular blocky; slightly hard, firm, moderately sticky and moderately plastic; few very fine, few fine, and few medium roots; few very fine and few fine tubular pores; common distinct clay films on faces of peds; 15 percent pebbles, 20 percent cobbles, and 5 percent stones; neutral (pH 6.8); clear wavy boundary. (8 to 14 inches thick)
2Crt--46 to 56 inches; light brown (7.5YR 6/4) weathered basalt, brown (7.5YR 4/4) moist; few distinct clay films on pararock fragments and few seams of illuvial clay lining fractures in the bedrock. (6 to 18 inches thick)
2R--56 inches; hard, unweathered basalt.
TYPE LOCATION: Klamath County, Oregon; about 0.75 mile west of Barnes Creek and 0.75 mile north of the Gerber Road along the Fremont National Forest boundary; 350 feet south and 150 feet west of the northeast corner of section 25, T. 38 S., R. 13 E.; USGS Horsefly Mountain 7.5 minute topographic quadrangle; 42 degrees 15 minutes 9 seconds north latitude and 121 degrees 6 minutes 54 seconds west longitude, NAD 27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in winter and spring and dry in summer and fall; xeric moisture regime that borders on aridic.
Mean annual soil temperature - 45 to 47 degrees F.
Mean summer soil temperature - 59 to 61 degrees F.
Mollic epipedon thickness - 20 to 35 inches, includes the Bt1 horizon in some pedons.
Argillic horizon thickness - 16 to 30 inches.
Depth to base of argillic horizon - 40 to 50 inches.
Depth to bedrock - 40 to 50 inches to a paralithic contact. The paralithic material below the contact is weathered basalt. Hard, unweathered bedrock is typically within 70 inches.
Particle-size control section - Clay content: 35 to 45 percent; Rock fragments: 15 to 30 percent, mainly pebbles and cobbles. Lithology of fragments is basalt.
Other features - Some pedons lack A3 horizons.
A1 horizon - Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Clay content: 18 to 24 percent.
Rock fragments: 15 to 35 percent.
Reaction: Slightly acid or neutral.
Organic matter content: 2 to 4 percent.
A2 horizon - Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Texture: Gravelly loam, cobbly loam, or very cobbly loam.
Clay content: 20 to 27 percent.
Rock fragments: 15 to 40 percent.
Reaction: Slightly acid or neutral.
Organic matter content: 2 to 4 percent.
Bt1 horizon - Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Clay loam or cobbly clay loam.
Clay content: 32 to 40 percent.
Rock fragments: 10 to 30 percent.
Reaction: Slightly acid or neutral.
Organic matter content: 1 to 3 percent.
Bt2 horizon - Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Clay, cobbly clay loam, or very cobbly clay.
Clay content: 37 to 50 percent.
Rock fragments: 10 to 40 percent.
Reaction: Slightly acid or neutral.
Organic matter content: 0.5 to 2 percent.
COMPETING SERIES: These are the Bertag, Kiyi, Sweiting, and Top series. Bertag, and Kiyi soils are very deep. Sweiting soils are moderately deep to lithic contacts. Top soils do not have subhorizons in the particle-size control section with more than 30 percent rock fragments, do not have paralithic material in the series control section, and have texture of silty clay loam or silty clay in the argillic horizon.
GEOGRAPHIC SETTING: Tallboy soils are on plateaus. They typically occur on summit or toeslope positions. These soils formed in slope alluvium and residuum derived from basalt and tuff. Slopes are 0 to 15 percent. Elevations range from 4,900 to 5,300 feet. The climate is characterized by cold, wet winters and warm, dry summers. The mean annual precipitation is 18 to 20 inches. The mean annual temperature is 43 to 45 degrees F., the mean January temperature is 25 to 28 degrees F., and the mean July temperature is 56 to 60 degrees F. The frost-free period is 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Casebeer, Devaul, Dranket, Mound, Norcross, and Pankeybasin soils. Casebeer and Norcross soils are clayey and shallow to thin duripans over bedrock. Devaul soils are deep to lithic contacts and have mollic horizons less than 20 inches thick. Dranket and Pankeybasin soils are fine and moderately deep to duripans over bedrock. Mound soils are clayey-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; medium surface runoff; slow permeability.
USE AND VEGETATION: Tallboy soils are used for timber production, wildlife habitat, livestock grazing, and recreation. The native vegetation is a forest canopy of ponderosa pine with an understory of Ross sedge, Idaho fescue, and squawcarpet.
DISTRIBUTION AND EXTENT: Southcentral Oregon. These soils are not extensive. MLRA 21.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES PROPOSED: Klamath County (Gerber Block of Fremont National Forest Area), Oregon, 1999. The name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 34 inches (A1, A2, A3, and Bt1 horizons).
Argillic horizon - The zone from 21 to 46 inches (Bt1 and Bt2 horizons).
Paralithic contact - The boundary at 46 inches to underlying soft, weathered bedrock (Crt layer).
Particle-size control section - The zone from 21 to 40 inches (Bt1 horizon and part of the Bt2 horizon).