LOCATION RANDCORE OREstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, nonacid, mesic Lithic Xerorthents
TYPICAL PEDON: Randcore extremely stony loam, on a nearly level basalt tableland at 3,360 feet elevation in rangeland. (Colors
are for moist soils unless otherwise noted.)
A1--0 to 1 inch; dark brown (7.5YR 3/4) extremely stony loam,
brown (7.5YR 5/4) dry; weak medium platy structure; soft, very friable, nonsticky and nonplastic; few very fine roots; common
very fine vesicular pores; 60 percent stones and 5 percent
gravel; slightly acid; abrupt smooth boundary. (1 to 2 inches
thick)
A2--1 to 6 inches; dark brown (7.5YR 3/4) loam, brown (7.5YR
5/4) dry; soft, very friable, nonsticky and nonplastic; very few roots; common very fine and fine irregular and few tubular and vesicular pores; 5 percent gravel; slightly acid; abrupt wavy boundary. (3 to 9 inches thick)
2R--6 inches; hard basalt.
TYPE LOCATION: Jackson County, Oregon; about 1 mile east of the intersection of Copco Road and the Oregon-California border,
about 100 feet west of the southeast corner of sec. 10, T. 41 S.,
R. 4 E.
RANGE IN CHARACTERISTICS: The soils are usually moist but are
dry throughout for 80 to 110 consecutive days in the four months
that follow the summer solstice. The mean annual soil
temperature is 47 to 53 degrees F. Depth to a lithic contact is
4 to 10 inches. The particle-size control section averages 12 to
25 percent clay with 5 to 15 percent gravel and 45 to 70 percent stones. Some of the stones are loose on the soil surface.
The A horizon has value of 3 or 4 moist and 4 or 6 dry, and
chroma of 3 or 4 moist and dry. It is silt loam or loam.
COMPETING SERIES: These are the
Etsel and
Flybow series. The
Etsel soil is somewhat excessively drained, occurs on slopes of
30 to 85 percent, gravel is the dominant rock size fragment and
the mean annual soil temperature is over 53 degrees F. The
Flybow soil is on slopes of 5 to 75 percent and cobbles are the dominant rock size fragment.
GEOGRAPHIC SETTING: The Randcore series consists of very
shallow, moderately well drained soils on basalt tablelands.
This landscape consists of patterned ground with the Randcore
series being the intermound component and the Shoat series being
the mounds. Slopes range from 0 to 5 percent. Elevation is
2,000 to 3,800 feet. These soils formed in loess over basalt.
The mean annual precipitation is 18 to 25 inches. The mean
annual temperature is 45 to 52 degrees F. The frost-free period
is 100 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the
Shoat series.
Shoat soils have a cambic horizon and are well drained.
DRAINAGE AND PERMEABILITY: Moderately well drained. The soil is ponded or runoff is very slow during periods of heavy
precipitation and during winter months. Permeability is
moderate.
USE AND VEGETATION: The soils are used for range and wildlife habitat. Native vegetation is annual hairgrass, mouse barley, Pacific foxtail and Canada Bluegrass.
DISTRIBUTION AND EXTENT: Southwestern Oregon and northern California. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Jackson County Area, Oregon, 1988.
REMARKS:
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.