LOCATION ROBINETTE OREstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Pachic Argixerolls
TYPICAL PEDON: Robinette silt loam, rangeland. (Colors are
for moist soil unless otherwise noted.)
A1--0 to 3 inches; very dark brown (10YR 2/2) silt loam,
dark grayish brown (10YR 4/2) dry; weak fine and very fine
granular structure; soft, very friable, nonsticky and
nonplastic; many very fine and fine roots; common very fine
and fine continuous, vertical, tubular pores; neutral (pH
6.8); clear smooth boundary. (2 to 6 inches thick)
A2--3 to 13 inches; very dark brown (10YR 2/2) silt
loam, dark grayish brown (10YR 4/2) dry; moderate fine and
medium subangular blocky structure; slightly hard, friable,
slightly sticky and slightly plastic; common very fine and
fine roots; common very fine and fine continuous, vertical,
tubular pores; neutral (pH 6.8); clear smooth boundary. (5
to 10 inches thick)
Bw--13 to 29 inches; dark brown (10YR 3/3) silty clay
loam, brown (10YR 4/3) dry; moderate fine and medium
subangular blocky structure; slightly hard, friable,
slightly sticky and slightly plastic; common very fine
roots; common very fine continuous tubular pores; neutral
(pH 6.8); gradual wavy boundary. (6 to 17 inches thick)
Bt1--29 to 44 inches; dark brown (10YR 3/3) silty clay
loam, brown (10YR 4/3) dry; moderate medium and coarse
subangular blocky structure; hard, firm, sticky and plastic;
common very fine roots; common very fine continuous tubular
pores; many moderately thick clay films on face of peds and
line pores; neutral (pH 6.8); gradual wavy boundary. (8 to
18 inches thick)
2Bt2--44 to 53 inches; brown (7.5YR 4/4) extremely
cobbly clay, strong brown (7.5YR 5/6) dry; moderate medium
and coarse subangular blocky structure; hard, firm, sticky
and plastic; few very fine roots; few very fine
discontinuous irregular pores; continuous thick clay films
on face of peds and line pores; about 25 percent gravel and
50 percent cobbles; neutral (pH 7.0); abrupt irregular
boundary. (7 to 14 inches thick)
2R--53 inches; basalt.
TYPE LOCATION: Baker County, Oregon; 6 miles SE of Halfway;
225 feet north and 200 feet east of the SW corner, sec. 28,
T. 8 S., R. 47 E.
RANGE IN CHARACTERISTICS: The thickness of the solum and
depth to bedrock is 40 to 60 inches. The mean annual soil temperature ranges from 47 to 52 degrees F. The thickness
of the mollic epipedon is 20 to 44 inches thick. The soils
are usually moist but are dry at depths of 4 to 12 inches
for 60 to 80 days during the summer. Depth to the 2Bt
horizon (argillic horizon) is 40 to 51 inches.
The A horizon has hue of 10YR or 7.5YR, value of 2 or 3
moist and 4 or 5 dry, and chroma of 2 or 3 moist and dry.
It has 0 to 10 percent gravel.
The Bw and Bt1 horizons have hue of 10YR through 5YR, value
of 2 through 4 moist and 3 through 5 dry, and chroma of 2
through 4 moist and 3 through 6 dry. It is silty clay loam
or clay loam with 27 to 35 percent clay. It has 0 to 15
percent gravel.
The 2Bt horizon has hue of 7.5YR of 5YR, value of 3 or 4
moist, 4 or 5 dry and chroma of 3 or 4 moist and 5 or 6 dry.
It has 40 to 60 percent clay, 20 to 30 percent gravel and 40
to 55 percent cobbles.
COMPETING SERIES: These are the
Banning,
Coolbrith,
Dotta,
Drews,
Gorman,
Harriman,
Supan,
Van Dusen,
Waha and
Wapinitia series. All of these soils except for the Gorman
soils have the argillic horizon occurring above 40 inches.
The Banning soils are dry for 45 to 60 days, have a mean
annual soil temperature of 52 to 56 degrees F, and are
somewhat poorly drained. The Coolbrith soils are somewhat
poorly drained and over 60 inches deep to bedrock. The
Dotta soils are over 60 inches deep to bedrock. The Drews
soils are dry for 100 to 115 days and are over 60 inches
deep to bedrock. The Gorman soils have a mean annual soil temperature of about 57 degrees F, have 20 to 28 percent
clay in the control section and contain 15 to 25 percent
coarse and very coarse sand throughout the profile. The
Harriman soils are dry for 80 to 120 days, have a paralithic
contact at 40 to 60 inches and have an influence of
diatomaceous earth. The Supan series description needs
updating; the soils are assumed to have a mean annual
soil temperature above 52 degrees F. The Van Dusen soils
have 25 percent or less coarse fragments in the argillic
horizon and are over 60 inches deep to bedrock. The Waha
soils are 20 to 40 inches deep to a lithic contact. The
Wapinitia soils have a solum 20 to 36 inches thick.
GEOGRAPHIC SETTING: Robinette soils are on hills at
elevations of 2,500 to 4,000 feet. Slopes are 2 to 12
percent. It is found on patterned land locally referred to
as biscuit-scabland. Robinette is the biscuit. The soils
formed in colluvium from basalt with an influence of loess
and volcanic ash in the upper horizons. Winters are cold
and moist, and summers are warm and dry. The mean annual precipitation is 14 to 20 inches. The mean annual
temperature is 45 to 50 degrees F. The frost-free period is
100 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Gwinly and
Rockly soils. Gwinly soils are clayey-skeletal, shallow and
are on scablands and gentle to steep side slopes. Rockly
soils are loamy-skeletal, very shallow and are on scablands
and gentle to steep side slopes.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is slow to
medium. Permeability is moderate over slow.
USE AND VEGETATION: These soils are used for range,
wildlife habitat and watershed purposes. Native vegetation
is bluebunch wheatgrass, Idaho fescue, Sandberg bluegrass,
big sagebrush and rabbitbrush.
DISTRIBUTION AND EXTENT: Northeastern Oregon. The series
is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Baker County Area, Oregon; 1988.