LOCATION DERAPTER OR

Established Series
Rev.RJK/TDT
12/2022

DERAPTER SERIES

The Derapter series consists of deep, well drained soils that formed in colluvium weathered from basalt. Derapter soils are on hill slopes and have slopes of 30 to 70 percent. The mean annual precipitation is about 12 inches and the mean annual temperature is about 44 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Calciargidic Argixerolls

TYPICAL PEDON: Derapter very stony sandy loam, on a slope of 40 percent in rangeland. (Colors are for moist soil unless otherwise noted.)

A1--0 to 3 inches; dark brown (10YR 3/3) very stony sandy loam, brown (10YR 5/3) dry; weak fine granular structure; loose, nonsticky and nonplastic; common very fine and medium, and many fine roots; few very fine irregular pores; 20 percent stones, 10 percent cobbles, and 10 percent gravel; neutral; clear smooth boundary.

A2--3 to 12 inches; dark brown (10YR 3/3) very stony sandy loam, grayish brown (10YR 5/2) dry; moderate medium granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine, fine and medium, and few coarse roots; many very fine and common fine irregular and tubular pores; 20 percent stones, 10 percent cobbles, and 10 percent gravel; neutral; clear wavy boundary. (Combined thickness of the A horizon is 10 to 15 inches)

Bt1--12 to 17 inches; brown (10YR 4/3) very stony sandy clay loam, pale brown (10YR 6/3) dry; moderate coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and coarse, and common fine and medium roots; few very fine, and common fine and medium irregular and tubular pores; many distinct clay films on faces of peds; 20 percent stones, 10 percent cobbles, and 10 percent gravel; slightly alkaline; clear wavy boundary.

Bt2--17 to 23 inches; dark yellowish brown (10YR 4/6) very stony sandy clay loam, brownish yellow (10YR 6/6) dry; moderate coarse subangular blocky structure; hard, friable, sticky and plastic; few very fine, and common fine and medium roots; few very fine and common fine and medium irregular and tubular pores; common distinct clay films on faces of peds; 20 percent stones, 10 percent cobbles, and 10 percent gravel; moderately alkaline; gradual wavy boundary.

Btk--23 to 31 inches; yellowish brown (10YR 5/6) very stony sandy clay loam, yellow (10YR 7/6) dry; moderate medium subangular blocky structure; slightly hard, friable, sticky and plastic; few very fine and medium, and many fine roots; few very fine and medium, and common fine irregular and tubular pores; common faint clay films on faces of peds; slightly effervescent; few medium rounded segregated lime in soft masses; 20 percent stones, 10 percent cobbles, and 10 percent gravel; moderately alkaline; gradual wavy boundary. (Combined thickness of the Bt and Btk horizon is 15 to 30 inches)

Bk--31 to 51 inches; dark yellowish brown (10YR 4/6) very gravelly sandy loam, yellow (10YR 7/6) dry; massive; soft, very friable, slightly sticky and slightly plastic; few fine and medium roots; many very fine and common fine irregular and tubular pores; strongly effervescent; common medium rounded segregated lime in soft masses; 10 percent stones, 10 percent cobbles, and 30 percent gravel; moderately alkaline; clear smooth boundary. (15 to 25 inches thick)

R--51 inches; fractured basalt

TYPE LOCATION: Lake County, Oregon; about 0.5 miles north of Highway 140, along the Sweeny Canyon Road, above the Rodgers Ranch; in the SW 1/4 SW 1/4 of section 13, T. 39 S., R. 23 E.

RANGE IN CHARACTERISTICS: The soils are moist in winter and spring. They are warmer than 41 degrees F. from April 15 to November 1, and they are dry throughout after July 1. The mean annual soil temperature is 44 to 47 degrees F. The mollic epipedon is 10 to 15 inches thick and does not include any part of the Bt. Depth to bedrock is 40 to 60 inches. Depth to secondary carbonates is 20 to 40 inches. It has 35 to 60 percent rock fragments, primarily cobbles and stones, and 25 to 35 percent clay in the particle-size control section.

The A horizon has value of 4 or 5 dry, 2 or 3 moist and chroma of 2 or 3 moist and dry. It has 10 to 25 percent gravel, and 10 to 35 percent cobbles and stones.

The Bt and Btk horizon has value of 6 or 7 dry, 3 to 5 moist, and chroma of 3 to 6 dry and moist. It is clay loam or sandy clay loam. It has 5 to 20 percent gravel and 15 to 40 percent cobbles and stones. It has few or common distinct or faint clay films on peds and in pores. It is neutral to moderately alkaline.

The Bk horizon has value of 6 or 7 dry, 3 or 4 moist and chroma of 4 to 6 dry and moist. It is loam or sandy loam with 20 to 50 percent gravel and 0 to 25 percent cobbles and stones. It is mildly or moderately alkaline.

COMPETING SERIES: This is the Majuba series. Majuba soils are moderately deep to bedrock.

GEOGRAPHIC SETTING: Derapter soils are on south facing hill slopes at elevations of 5,200 to 7,600 feet. Slopes range from 30 to 70 percent. The soils formed in colluvium weathered from basalt. The climate is characterized by cold moist winters and hot dry summers. The mean annual precipitation is 11 to 16 inches. The mean annual temperature is 45 to 47 degrees F., mean January temperature is 27 to 29 degrees F., and mean July temperature is 59 to 61 degrees F. The frost-free period is 50 to 90 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Lonegrave, Lambring and Westbutte soils. Lonegrave soils have a mesic soil temperature regime and have an ochric epipedon. Lambring and Westbutte soils are on north slopes and have a mollic epipedon over 20 inches thick and lack carbonates and an argillic horizon.

DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.

USE AND VEGETATION: Derapter soils are used for livestock grazing and wildlife habitat. Native vegetation is mainly mountain big sagebrush, antelope bitterbrush, Idaho fescue, and bluebunch wheatgrass.

DISTRIBUTION AND EXTENT: Southeastern Oregon; MLRA 23. The series is of minor extent.

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:

Mollic epipedon: the zone from 0 to 12 inches (A1 and A2 horizons)

Argillic horizon: the zone from 12 to 31 inches (Bt1, Bt2, Btk horizons)

Soft powdery secondary lime from 23 to 51 inches (Btk, Bk horizons)

The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Reno MLRA office, without review of the soil series property data. The remainder of this document has not been updated.

National Cooperative Soil Survey
U.S.A.