LOCATION GYPNEVEE                WY+SD

Established Series
Rev. JWW
06/2011

GYPNEVEE SERIES

The Gypnevee series consists of deep and very deep, well drained soils that formed in material weathered from gypsum or gypsiferous siltstone. Gypnevee soils are on ridges and hillslopes on uplands. Slopes range from 0 to 30 percent. The mean annual precipitation is about 406 mm and the mean annual air temperature is about 9 degrees C.

TAXONOMIC CLASS: Loamy over fine-gypseous, mixed over hypergypsic, superactive, mesic Aridic Ustorthents

TYPICAL PEDON: Gypnevee silt loam, rangeland. (Colors are for dry soil unless otherwise stated.)

A--0 to 13 cm; reddish brown (5YR 5/4) silt loam, dark reddish brown (5YR 3/4) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; few fine roots; strongly effervescent; moderately alkaline; clear smooth boundary. (10 to 20 cm thick)

AC--13 to 41 cm; light reddish brown (5YR 6/4) silt loam, yellowish red (5YR 4/6) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; few very fine and fine roots; strongly effervescent; moderately alkaline; clear smooth boundary. (15 to 30 cm thick)

C1--41 to 51 cm; pink (5YR 7/4) silt loam, yellowish red (5YR 4/6) moist; weak coarse subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; strongly effervescent; 50 percent gypsum and calcium carbonate, mainly disseminated, throughout; slightly alkaline; clear smooth boundary.

C2--51 to 117 cm; reddish yellow (5YR 7/6) silt loam, yellowish red (5YR 5/6) moist; massive; soft, very friable, slightly sticky and slightly plastic; strongly effervescent, 60 percent gypsum and calcium carbonate in soft rounded masses, threads and seams; slightly alkaline. (Combined thickness of the C horizon is 63 to 110 cm)

Cr--117 to 152 cm; reddish brown gypsum.

TYPE LOCATION: Crook County, Wyoming; NW1/4 NW1/4 of Sec. 4, T. 50N., R.62W. Duling Hill Quadrangle, 44 degrees 21 minutes 14 seconds north latitude and 104 degrees 18 minutes 40 seconds west longitude; NAD 83.

RANGE IN CHARACTERISTICS:

Mean annual soil temperature: 9 to 11 degrees C
Depth to bedrock: typically is 102 to 152 cm; however, some pedons have bedrock between 152 and 177 cm

Particle-size control section:
Calcium carbonate plus gypsum: 40 to 60 percent

A Horizon:
Hue: 7.5YR, 5YR, or 2.5YR
Value: 5 to 7, 4 to 6 moist
Chroma: 3 to 6
Texture: loam, silt loam, or very fine sandy loam
Reaction: slightly alkaline or moderately alkaline

AC Horizon:
When present, has properties similar to the A and C horizons. Some pedons do not have an AC horizon

C Horizon:
Hue: 7.5YR, 5YR or 2.5YR
Value: 5 to 7, 4 to 6 moist
Chroma: 3 to 6
Texture: loam, silt loam, or very fine sandy loam
Clay content: 18 to 35 percent
Gypsum content: 40 to 60 percent
Calcium carbonate content: 15 to 40 percent
Few secondary carbonates and gypsum masses occur in some pedons
Reaction: slightly alkaline or moderately alkaline

COMPETING SERIES: There are no competing series in this family.

GEOGRAPHIC SETTING:
Parent material: alluvium and residuum weathered from reddish sedimentary rock (siltstone) high in gypsum
Landform: ridges and hillslopes on uplands; sinkholes 6 m to 92 m in diameter are commonly associated with the landscapes
Slopes: 0 to 30 percent
Elevation: 900 to 1,585 meters
Mean annual temperature: 7 to 10 degrees C
Mean annual precipitation: 355 to 510 mm
Precipitation pattern: Over one-half the mean annual precipitation falls as snow and rain during the period March through June
Frost-free season: 100 to 130 days

GEOGRAPHICALLY ASSOCIATED SOILS: All of these soils have less than 40 percent gypsum plus carbonates in the mineralogy control section; additionally,
Nevee - occurs on similar landscape positions as Gypnevee soils
Tilford and Vale- are fine-silty and have mollic epipedons; they occur on lower landscape positions than Gypnevee soils

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; moderately low and moderately high saturated hydraulic conductivity; low to high runoff, depending on slope.

USE AND VEGETATION: Gypnevee soils are used for rangeland, pasture, hayland, and wildlife habitat. Native vegetation is little bluestem, western wheatgrass, needleandthread, and blue grama.

DISTRIBUTION AND EXTENT: The Red Valley physiographic area in the Black Hills Foothills of Wyoming and South Dakota; LRR G, MLRA 61. The series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado

SERIES ESTABLISHED: Lawrence County, South Dakota, March, 1977.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Soil moisture: Aridic-ustic
Ochric epipedon - 0 to 13 cm (A horizon)
Strongly contrasting particle -size adn mineralogy control section: loamy over fine-gypseous and mixed over hypergypsic
Hypergypsic mineralogy - over 40 percent gypsum in C horizons
Paralithic contact - 117 cm (Cr horizon)

Taxonomy Version: Keys to Soil Taxonomy, Eleventh Edition, 2010

The series soil moisture regime is revised to aridic-ustic to reflect more current precipitation data and better understanding of soil moisture characteristics within the series domain. Depth to bedrock is revised to include very deep components of the same soil

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National Cooperative Soil Survey
U.S.A.