LOCATION LONGBRANCH OREstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Pachic Argixerolls
TYPICAL PEDON: Longbranch silt loam, on a 25 percent
north-facing slope, rangeland. (Colors are for moist soil
unless otherwise noted.)
A1--0 to 4 inches; very dark gray (10YR 3/1) silt loam,
grayish brown (10YR 5/2) dry; moderate very fine granular
structure; soft, very friable, nonsticky and nonplastic;
many very fine and fine roots; many very fine and fine
irregular pores; 5 percent gravel; neutral (pH 6.6); clear
smooth boundary. (4 to 6 inches thick)
A2--4 to 22 inches; very dark grayish brown (10YR 3/2)
silt loam, grayish brown (10YR 5/2) dry; moderate fine and
medium subangular blocky structure; slightly hard, very
friable, slightly sticky and slightly plastic; common very
fine and fine and few medium roots; many very fine and fine
tubular pores; 10 percent gravel; neutral (pH 6.8); abrupt
wavy boundary. (8 to 18 inches thick)
2BA--22 to 30 inches; very dark grayish brown (10YR 3/2)
gravelly clay loam, brown (10YR 5/3) dry; moderate fine and
medium subangular blocky structure; slightly hard, friable,
slightly sticky and slightly plastic; common very fine and
fine and few medium roots; many very fine and fine tubular
pores; 20 percent gravel and 5 percent cobbles; neutral (pH
7.0); clear smooth boundary. (8 to 12 inches thick)
2Bt--30 to 38 inches; yellowish brown (10YR 5/4) very
gravelly clay, light yellowish brown (10YR 6/4) dry;
moderate medium and coarse angular blocky structure; hard,
firm, sticky and plastic; few very fine roots; common very
fine and fine tubular pores; common moderately thick clay
films on ped faces and line pores; 30 percent gravel and 10
percent cobbles; neutral (pH 7.2); gradual smooth boundary.
(8 to 10 inches thick)
2Btk1--38 to 45 inches; yellowish brown (10YR 5/4) very
cobbly clay, light yellowish brown (10YR 6/4) dry; moderate
medium and coarse subangular blocky structure; hard, firm,
sticky and plastic; no roots; common very fine and fine
tubular pores; many thick clay films on ped faces and line
pores; strongly effervescent with segregated lime blotches;
30 percent gravel and 25 percent cobbles; mildly alkaline
(pH 7.6); clear smooth boundary. (5 to 10 inches thick)
2Btk2--45 to 52 inches; light yellowish brown (10YR 6/4)
extremely cobbly clay loam, very pale brown (10YR 7/4) dry;
weak fine and medium subangular blocky structure; slightly
hard, friable, slightly sticky and slightly plastic; no
roots; many very fine and fine tubular pores; few thin clay
films line pores; strongly effervescent; 45 percent cobbles
and 20 percent gravel; mildly alkaline (pH 7.8); gradual
smooth boundary. (6 to 15 inches thick)
3R--52 inches; highly fractured greenstone.
TYPE LOCATION: Baker County, Oregon; located in the SE1/4SE1/4SW1/4SW1/4 of section 14, T. 12 S., R. 41 E.
RANGE OF CHARACTERISTICS: These soils are usually moist,
but are dry between depths of 4 and 12 inches for 45 to 90 consecutive days following the summer solstice. The mean
annual soil temperature is 42 to 47 degrees F. Depth to
bedrock is typically 40 to 60 inches but may be greater than
60 inches in some pedons. The solum is neutral to mildly
alkaline. The thickness of the mollic epipedon is 20 to 30
inches. Depth to the 2Bt horizon is 20 to 30 inches.
The A horizon has value of 2 or 3 moist, 3 through 5 dry and
chroma of 1 or 2 moist and dry. It has 0 to 10 percent
gravel and 0 to 5 percent cobbles.
The 2BA horizon has value of 3 or 4 moist, 4 or 5 dry and
chroma of 2 or 3 moist and dry. It is silty clay loam or
clay loam, with 27 to 35 percent clay. It has 20 to 30
percent gravel and 0 to 10 percent cobbles and stones.
The 2Bt horizon has value of 4 or 5 moist, 5 or 6 dry and
chroma of 3 or 4 moist and dry. It is silty clay or clay,
with 40 to 50 percent clay. It has 20 to 30 percent gravel
and 10 to 30 percent cobbles and stones. The lower portion
of this horizon is strongly to violently effervescent, with
the lime concentrated in segregated blotches.
The 2Btk horizon has value of 5 or 6 moist, 6 or 7 dry and
chroma of 3 or 4 moist and dry. It is loam or clay loam,
with 20 to 30 percent clay. It has 20 to 40 percent gravel
and 30 to 50 percent cobbles and stones. The upper portion
of this horizon is strongly to violently effervescent, with
the lime concentrated in the segregated blotches.
COMPETING SERIES: These are the
Menbo(T),
Royst, Shepan,
and
Snell series. Menbo and Snell soils are 20 to 40 inches
deep to a lithic contact. Royst soils are 20 to 40 inches
deep to a paralithic contact. Shepan soils have 20 to 40
percent gravel in the surface, lack the loess influence and lithologic discontinuity at the argillic horizon.
GEOGRAPHIC SETTING: Longbranch soils are on stable to
meta-stable north-facing side slopes of hills. Elevations
range from 3,800 to 5,700 feet. Slope is 12 to 50 percent.
The soils formed in loess over colluvium from greenstone.
The mean annual precipitation is 12 to 16 inches. The mean
annual temperature is 40 to 45 degrees F. The frost-free
period is 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Ateron,
Durkee and
Roostercomb soils. Ateron soils are 10 to 20
inches deep and are clayey-skeletal. Durkee soils are 20 to
40 inches deep, are fine textured, and have a calcic
horizon. Roostercomb soils are 20 to 40 inches deep and clayey-skeletal.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is medium
to rapid. Permeability is slow.
USE AND VEGETATION: These soils are used for rangeland and
wildlife habitat. The native vegetation is mainly mountain
big sagebrush, wax currant, Idaho fescue and basin wildrye
with minor amounts of prairie junegrass and green
rabbitbrush.
DISTRIBUTION AND EXTENT: East central and northeastern
Oregon. The soils are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Baker County Area, Oregon; 1988.
REMARKS: Diagnostic horizons and features in this pedon
are:
Mollic epipedon - the zone from the surface of the soil to a
depth of approximately 30 inches (A1, A2, 2BA horizons).
Argillic horizon - the zone from approximately 30 to 45
inches (2Bt, 2Btk horizons).
Pachic feature - mollic epipedon to a depth of 30 inches.