LOCATION SPENS                   WA+ID

Established Series
Rev. NCD/RWL/RJS
10/2016

SPENS SERIES

The Spens series consists of very deep, somewhat excessively drained soils formed in glacial outwash and colluvial material of mixed mineralogy. Spens soils are on terrace escarpments, treads and kames. Slopes are 15 to 90 percent. The mean annual precipitation is about 18 inches and the mean annual temperature is about 47 degrees F.

TAXONOMIC CLASS: Sandy-skeletal, mixed, mesic Typic Xerorthents

TYPICAL PEDON: Spens extremely gravelly loamy sand, range. (Colors are for dry soil unless otherwise stated.)

A--0 to 7 inches; grayish brown (10YR 5/2) extremely gravelly loamy sand, very dark grayish brown (10YR 3/2) moist; weak fine and medium granular structure; soft, friable, nonsticky and nonplastic; many fine and medium roots; 65 percent gravel; neutral (pH 6.6); clear wavy boundary. (3 to 9 inches thick)

C1--7 to 17 inches; brown (10YR 5/3) extremely gravelly loamy sand, dark yellowish brown (10YR 3/4) moist; single grain; loose; common fine roots; 55 percent gravel and 10 percent cobbles; neutral (pH 6.8); clear wavy boundary. (8 to 15 inches thick)

C2--17 to 60 inches; brown (10YR 5/3) extremely gravelly loamy coarse sand; dark yellowish brown (10YR 3/4) moist; single grain; loose; few fine roots; 65 percent gravel and 10 percent cobbles; neutral (pH 6.8).

TYPE LOCATION: Stevens County, Washington; about 2 miles east of Long Lake Dam, 2,400 feet south and 1,600 feet west of the northeast corner of section 16, T.27N., R.40E., WM.

RANGE IN CHARACTERISTICS:
Soil moisture regime dry 60 to 90 consecutive days following summer solstice between depths of 12 and 35 inches
Mean annual soil temperature 47 to 52 degrees F.
Rock fragments 35 to 80 percent in particle-size control section dominantly of gravel size
Calcium carbonate and silica accumulations underside of some gravel and cobbles

A horizon
Value - 4 to 6 dry, 2 or 3 moist
Chroma - 2 to 4, moist or dry.
Texture loamy sand, loamy coarse sand
Rock fragment content 35 to 80 percent total
Gravel content 35 to 75 percent
Cobble content 0 to 10 percent
Stone content 0 to 15 percent
Reaction slightly acid or neutral
AC horizon present in some pedons

C horizon
Hue 10YR, 2.5Y or is multi-colored
Value - 5 to 7 dry, 3 to 5 moist
Chroma - 2 to 4, dry or moist
Texture - loamy sand, loamy coarse sand or coarse sand
Rock fragment content 35 to 80 percent
Gravel content 20 to 55 percent
Cobble content 2 to 50 percent
Stone content 0 to 5 percent
Reaction slightly acid to slightly alkaline

COMPETING SERIES: These are the Atter, Carlsborg, Marblespring and Valcreek series. Atter soils have a mean annual soil temperature of 52 to 59 degrees F. and are dry for more than 90 consecutive days. Carlsborg soils have Bw horizons and a solum depth greater than 10 inches thick. Marblespring soils are dominated by fine gravel in the particle-size control section, have E&Bt horizons and have a solum depth greater than 10 inches thick. Valcreek soils are 20 to 40 inches deep to a paralithic contact.

GEOGRAPHIC SETTING: Spens soils are on outwash terraces, terrace escarpments, treads and kames. Slopes range from 15 to 90 percent. The soils formed in gravelly glacial outwash of mixed mineralogy. Elevation ranges from 1,300 to 4,000 feet. The climate is characterized by warm, dry summers and cool, moist winters. The mean annual precipitation is 15 to 22 inches. The mean annual temperature is 46 to 50 degrees F. The frost-free season is 100 to 140 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dart, Marble, and Springdale soils. Dart and Marble soils are sandy throughout and are on outwash terraces. Springdale soils have a cambic horizon and are on outwash terrace treads and risers.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; slow to medium runoff; very rapid permeability.

USE AND VEGETATION: These soils are used mainly for grazeable woodland, recreation, and wildlife habitat. Potential natural vegetation is mainly widely spaced ponderosa pine with an understory of bluebunch wheatgrass, red threeawn, needleandthread, lupine, eriogonum and arrowleaf balsamroot.

DISTRIBUTION AND EXTENT: Northeastern Washington. MLRA 43. The series is moderately extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Lincoln County, Washington, 1978.

REMARKS: Diagnostic horizons and features recognized in this pedon include:
Ochric epipedon the zone from 0 to 7 inches (A horizon)
Particle-size control section the zone from 10 to 40 inches that averages 73 percent rock fragments (part of the C1 and C2 horizons)

---

National Cooperative Soil Survey
U.S.A.