LOCATION STREVELL IDEstablished Series
The Strevell series consists of very deep, well-drained soils that have
moderate permeability. They have formed in mixed alluvium on coalesced
fan terraces and have slopes of 1 to 12 percent. The average annual
temperature is about 46 degrees F; the average annual precipitation is
about 10 inches.
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Xeric Haplocalcids
TYPICAL PEDON: Strevell silt loam - rangeland. On a 2 percent smooth
slope, west aspect, 4,920 feet elevation. The profile was moist
throughout when described. Colors are for air dry soil unless
otherwise stated. This profile was described on May 19, 1982.
A--0 to 2 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3)
moist; moderate coarse platy structure parting to moderate fine platy;
soft, very friable, slightly plastic; common very fine roots; many very
fine vesicular pores; moderately effervescent; 1 percent pebbles;
strongly alkaline (pH 8.6); abrupt smooth boundary. (1 to 4 inches
thick)
Bw--2 to 7 inches; very pale brown (10YR 7/3) silt loam, brown
(10YR 4/3) moist; weak very coarse prismatic structure parting to
moderate medium subangular blocky; slightly hard, very friable,
slightly sticky and slightly plastic; common very fine roots; many very
fine tubular pores; moderately effervescent; 1 percent pebbles; very
strongly alkaline (pH 9.4); clear smooth boundary. (2 to 8 inches
thick)
Bk1--7 to 13 inches; very pale brown (10YR 7/3) silt loam, dark
yellowish brown (10YR 4/4) moist; weak medium and coarse subangular
blocky structure; slightly hard, very friable; common very fine roots;
many very fine tubular pores; strongly effervescent; 1 percent pebbles;
very strongly alkaline (pH 9.2); clear smooth boundary. (5 to 15
inches thick)
Bk2--13 to 25 inches; very pale brown (10YR 8/3) silt loam,
yellowish brown (10YR 5/4) moist; massive; slightly hard, very friable,
slightly sticky and slightly plastic; few very fine roots; many very
fine and few fine tubular pores; violently effervescent; 2 percent
pebbles; strongly alkaline (pH 9.0); clear smooth boundary. (10 to 20
inches thick)
Bk3--25 to 31 inches; white (10YR 8/2) silt loam, brown (10YR 5/3)
moist; massive; slightly hard, very friable; common very fine tubular
pores; 15 percent nodules that are very hard dry and friable moist;
violently effervescent; 2 percent pebbles; strongly alkaline (pH 8.6);
clear wavy boundary. (8 to 15 inches thick)
2Bkz--31 to 42 inches; very pale brown (10YR 7/3) very gravelly
loam, brown (10YR 4/3) moist; massive; slightly hard; very friable;
many very fine and few fine tubular pores; strongly effervescent
matrix; violently effervescent lime segregated into few fine
irregularly shaped soft masses and filaments; salt segregated into
common fine irregularly shaped soft masses and filaments; 45 percent
pebbles; moderately alkaline (pH 8.4); gradual wavy boundary. (5 to 15
inches thick)
2Ckz--42 to 50 inches; very pale brown (10YR 7/3) very gravelly
loam, brown (10YR 4/3) moist; massive; slightly hard; very friable;
many very fine irregular pores; moderately effervescent matrix;
violently effervescent lime segregated into few fine irregularly shaped
soft masses and filaments on the underside of pebbles; salt segregated
into few fine irregularly shaped soft masses and filaments; 5 percent
cobbles and 45 percent pebbles; moderately alkaline (pH 8.4); gradual
wavy boundary. (5 to 20 inches thick)
3C--50 to 60 inches; pale brown (10YR 6/3) extremely gravelly loamy
coarse sand, dark yellowish brown (10YR 4/4) moist; single grained;
loose and loose; many very fine irregular pores; moderately
effervescent matrix; violently effervescent lime segregated into few
fine irregularly shaped soft masses and filaments on the underside of
pebbles; 3 percent cobbles and 70 percent pebbles; moderately alkaline
(pH 8.2).
TYPE LOCATION: Cassia County, Idaho; about 1000 feet east and 400 feet
north of the southwest corner of sec. 14, T.15S., R.27E.
RANGE IN CHARACTERISTICS:
Particle size control section - 10 to 15 percent clay, 5 to 30 percent
rock fragments
Depth to secondary lime - 4 to 10 inches
Depth to calcic horizon - 10 to 20 inches
Depth to first lithologic discontinuity - 25 to 40 inches
A horizons
Value- 6 or 7 dry, 4 or 5 moist
Chroma- 2 through 4
Reaction - moderately through very strongly alkaline
Bk horizons
Value- 6 through 8 dry, 4 through 7 moist
Chroma- 2 through 4
Texture - L, SIL, GR-L, or GR-SIL
Coarse fragment content - 0 to 30 percent
Reaction - moderately through very strongly alkaline
2Bkz horizons
Value- 7 or 8 dry, 4 through 7 moist
Chroma- 2 through 4
Texture - GRV-L or GRV-SL
Rock fragment content - 35 to 55
Reaction - moderately or strongly alkaline
3C horizons
Value- 5 through 8 dry, 4 through 6 moist
Chroma- 2 through 4
Texture - GRV-S, GRV-SL, GRV-LS, GRX-COS, GRX-LCOS, CBV-S
Rock fragment content - 40 to 75 percent
Reaction - mildly or moderately alkaline
COMPETING SERIES: These are the Bertelson, Declo, Eccles, Escalante,
Palisade, and Somsen series. Bertelson soils formed in alluvium
derived from volcanic tuff and igneous rocks and have a bulk density of
less than 1.2 gr/cc. Declo soils average less than 15 percent gravel
in the control section and lack very gravelly horizons. Eccles and
Escalante soils have moderately coarse and coarse textures throughout
the control section. Palisade soils lack coarse fragments and a
lithologic discontinuity in the control section. Somsen soils are
moderately deep to bedrock.
GEOGRAPHIC SETTING: Strevell soils are on coalesced fan terraces.
Slopes range from 1 to 12 percent. Elevation ranges from 4,400 to
5,600 feet. The soil formed in mixed alluvium. The average annual
precipitation is about 8 to 12 inches; the average annual air
temperature is about 45 to 47 degrees F; and the frost-free season is
95 to 130 days. Strevell soils are normally saline. Where this soil
is used for irrigated crops, the soil is nonsaline to slightly saline.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Darkbull, Declo, and
Mellor soils. Darkbull soils have a skeletal control section. Mellor
soils have a natric horizon and a fine silty control section. They are
on fan terraces.
DRAINAGE AND PERMEABILITY: Well drained; moderately permeable; slow to
medium runoff.
USE AND VEGETATION: Strevell soils are used for rangeland and
irrigated crops. The native vegetation is Greasewood, bottlebrush
squirreltail, shadscale, and Nuttall saltbush.
DISTRIBUTION AND EXTENT: This series is moderately extensive in south
central Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Cassia County, Idaho, 1986.
REMARKS: Diagnostic horizons and features recognized in this pedon
are:
Ochric Epipedon - The zone from the surface to 10 inches (A, Bw, Bk1
horizons)
Calcic Horizon - The zone from 13 to 31 inches (Bk2 and Bk3 horizons)
Particle Size Control Section - The zone from 10 to 40 inches (Bk1,
Bk2, Bk3, and 2Bkz horizons)
National Cooperative Soil Survey