LOCATION COGLIN OREstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Xeric Paleargids
TYPICAL PEDON: Coglin extremely stony loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 2 inches; light brownish gray (10YR 6/2) extremely stony loam, very dark grayish brown (10YR 3/2) moist; weak thin platy structure; soft, very friable, sticky and slightly plastic; many very fine and fine roots; many very fine discontinuous vesicular pores; 20 percent gravel, 15 percent cobbles and 40 percent stones; neutral (pH 6.8); abrupt wavy boundary. (2 to 5 inches thick)
2Bt--2 to 7 inches; dark yellowish brown (10YR 4/4) clay, dark brown (10YR 4/3) moist; strong fine prismatic structure; extremely hard, very firm, sticky and very plastic; common very fine and fine roots; few very fine discontinuous irregular pores; 10 percent fine gravel; many continuous prominent clay films in pores and on ped faces; neutral (pH 7.2); clear wavy boundary. (3 to 15 inches thick)
3C--7 to 16 inches; yellowish brown (10YR 5/6) silty clay loam, dark yellowish brown (10YR 4/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; 10 percent gravel; mildly alkaline (pH 7.8); clear smooth boundary. (5 to 12 inches thick)
4Ck--16 to 60 inches; dark yellowish brown (10YR 4/4) silty clay loam, dark yellowish brown (10YR 4/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; 5 percent gravel; strongly effervescent, lime segregated in common irregular filaments and seams; moderately alkaline (pH 8.4).
TYPE LOCATION: Lake County, Oregon; NE1/4, NW1/4, SW1/4 of section 31, T. 36 S., R. 23 E.
RANGE IN CHARACTERISTICS: The soils are dry for more than half the time when soil temperature is greater than 41 degrees F. The soil temperature is above 41 degrees F.
f.om about March 15 to about November 15. The mean annual soil temperature is 45 to 47 degrees F. Depth to soft powdery secondary lime is 10 to 30 inches. Depth to bedrock is over 60 inches. The particle-size control section has an average of 35 to 45 percent clay. There is a clay increase of 15 to 25 percent absolute between the A and 2Bt horizons. The combined A and 2Bt horizon thickness is 5 to 20 inches.
The A horizon has hue of 10YR, value of 3 or 4 moist, 6 dry and chroma of 2 moist and dry. It has 15 to 20 percent gravel, 15 to 20 percent cobbles and 30 to 40 percent stones. It is a loam with a high percentage of volcanic ash. The sand fraction is mostly very fine and fine sand. It has 1 to 2 percent organic matter.
The 2Bt horizon has hue of 7.5YR or 10YR, value of 4 moist, 4 to 6 dry, and chroma of 3 or 4 moist and 4 dry. It has 5 to 15 percent fine gravel. Clay films are faint to prominent. Structure is moderate to strong prismatic parting to angular blocky. It is clay with 40 to 50 percent clay content. It has 1 to 2 percent organic matter.
The 3C horizon has hue of 7.5YR or 10YR, value of 4 moist, 5 or 6 dry and chroma of 3 or 4 moist and 4 to 6 dry. It has 5 to 20 percent fine gravel, and 0 to 10 percent cobbles. It is silty clay loam or clay loam with 30 to 40 percent clay.
The 4Ck horizon has hue of 7.5YR or 10YR, value of 4 moist, 4 to 6 dry and chroma of 4 moist and 4 to 6 dry. It has 5 to 20 percent fine gravel and 0 to 10 percent cobbles. It is silty clay loam or clay loam with a clay content of 30 to 40 percent in the upper part and ranges to silt loam or loam below a depth of 40 inches. This horizon may contain thin lenses of brittle material 1 to 3 inches thick. It is strongly or violently effervescent.
COMPETING SERIES: These are the Freznik, Toney, and Zoesta series. Freznik soils are 20 to 40 inches to a lithic contact. Toney soils are 20 to 40 inches to a paralithic contact. Zoesta soils have a combined A and Bt thickness of 30 to 40 inches and typically have durinodes beneath the Bt horizon.
GEOGRAPHIC SETTING: Coglin soils are on tablelands at elevations of 5,000 to 6,000 feet. Slopes range from 2 to 15 percent. These soils formed in colluvium and residuum from basalt and tuff. The climate is characterized by cold moist winters and hot dry summers. The mean annual temperature is 40 to 45 degrees F. The mean annual precipitation is 10 to 16 inches. The frost-free period is 50 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Drakesflat, Fertaline, Ratto, and Hart series. Drakesflat soils are moderately deep to bedrock. Fertaline and Ratto soils are moderately deep to a duripan. Hart soils have greater than 45 percent clay in the particle-size control section.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
DISTRIBUTION AND EXTENT: Tableland areas of Southeastern Oregon, MLRA 23. The series is not extensive.
USE AND VEGETATION: Coglin soils are used for livestock grazing and wildlife habitat. Native vegetation is black sagebrush, Sandberg bluegrass and bottlebrush squirreltail.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Lake County, Oregon, Southern Part; 1991.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon
Argillic horizon - from 2 to 7 inches
Pale feature - absolute clay increase of 20 percent between the A and 2Bt horizons.
Particle-size control section - the zone from 2 to 40 inches.
NSTH 17, RECLASSIFICATION ONLY, 3/95