LOCATION GREENSCOMBE OREstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Typic Haploxerolls
TYPICAL PEDON: Greenscombe loam, rangeland. (Colors are
for moist soil unless otherwise noted.)
A1--0 to 6 inches; very dark grayish brown (10YR 3/2)
loam, grayish brown (10YR 5/2) dry; moderate fine and medium subangular blocky structure; soft, very friable, slightly
sticky and slightly plastic; common fine and few medium
roots; common very fine tubular and irregular pores; mildly
alkaline (pH 7.4); gradual wavy boundary. (5 to 8 inches
thick)
A2--6 to 11 inches; dark brown (10YR 3/3) loam, grayish
brown (10YR 5/2) dry; moderate fine and medium subangular
blocky structure; soft, very friable, slightly sticky and
slightly plastic; few fine and medium roots; common very
fine and fine tubular pores; mildly alkaline (pH 7.6); clear
wavy boundary. (5 to 8 inches thick)
2Bw--11 to 19 inches; dark yellowish brown (10YR 3/4)
sandy clay loam, brown (10YR 5/3) dry; moderate medium and
coarse subangular blocky structure; slightly hard, friable,
sticky and plastic; few fine and medium roots; common fine
tubular pores; 10 percent gravel; mildly alkaline (pH 7.8);
gradual wavy boundary. (5 to 10 inches thick)
2C1--19 to 26 inches; dark yellowish brown (10YR 3/6)
sandy clay loam, yellowish brown (10YR 5/4) dry; weak fine
and medium subangular blocky structure; slightly hard,
friable, slightly sticky and slightly plastic; few medium
roots; common fine tubular pores; 10 percent gravel; mildly
alkaline (pH 7.8); gradual wavy boundary. (5 to 10 inches
thick)
2C2--26 to 30 inches; dark yellowish brown (10YR 3/6)
gravelly sandy loam, yellowish brown (10YR 5/6) dry;
massive; loose, nonsticky and nonplastic; common fine
tubular pores; 30 percent gravel; mildly alkaline (pH 7.6).
(0 to 6 inches thick)
3Cr--30 inches; weathered quartz diorite.
TYPE LOCATION: Baker County, Oregon; about 4 miles east of
North Powder, in the SE1/4SW1/4 sec. 32, T. 6 S., R. 40 E.
RANGE IN CHARACTERISTICS: These soils are usually moist but
are dry in all parts between 4 and 12 inches for 60 to 80
consecutive days during the summer. Mean annual soil
temperature is about 47 to 51 degrees F. Depth to weathered
bedrock ranges from 20 to 40 inches. Reaction ranges from
neutral to mildly alkaline. Thickness of the mollic
epipedon is 10 to 16 inches.
The A horizon has value of 2 or 3 moist, 4 or 5 dry, and
chroma of 2 or 3 moist and dry. It has 0 to 10 percent
gravel.
The 2Bw horizon has value of 3 or 4 moist, 4 through 6 dry,
and chroma of 3 or 4 moist and dry. It is sandy clay loam,
clay loam, or loam. It has 5 to 15 percent gravel and 20 to
35 percent clay.
The 2C horizon has value of 3 or 4 moist, 5 or 6 dry and
chroma of 3 through 6 moist and dry. It is sandy loam or
sandy clay loam, and has 5 to 35 percent gravel.
COMPETING SERIES: These are the
Crowshaw,
Laki,
Odo, and
Tocaloma series. The Crowshaw, Laki, and Odo soils
are deeper than 40 inches to bedrock. Tocaloma soils
are medium to slightly acid, and have mean annual soil
temperature of 55 to 59 degrees F.
GEOGRAPHIC SETTING: Greenscombe soils are on low hills at
elevations 3,200 to 3,800 feet. Slopes are 2 to 35 percent.
The soils formed in aeolian materials over colluvium derived
from quartz diorite. The mean annual precipitation is 12 to
16 inches. The mean annual temperature is 45 to 50 degrees
F. The frost-free period is 100 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Brownscombe,
Keating, and
North Powder soils. Brownscombe and North
Powder soils have an aridic moisture regime. The Keating
soils have a clayey argillic horizon and are formed from
greenstone.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium
runoff; moderate permeability.
USE AND VEGETATION: Rangeland. The native vegetation is
Idaho fescue, bluebunch wheatgrass, Sandberg bluegrass,
Thurber needlegrass, and big sagebrush.
DISTRIBUTION AND EXTENT: Eastern Oregon. The series is of
small 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 11 inches (A1 and A2 horizons).
Cambic horizon - the zone from approximately 11 to 19 inches
(2Bw horizon).
Paralithic contact - weathered quartz diorite at about 30
inches.