LOCATION GERDA NDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Leptic Torrertic Natrustolls
TYPICAL PEDON: Gerda loam, in native pasture. (Colors are for dry soil unless otherwise noted)
E--0 to 2 inches; light brownish gray (2.5Y 6/2) loam, dark grayish brown (2.5Y 4/2) moist; moderate medium and thick platy structure; hard, friable, slightly sticky and slightly plastic; many very fine and fine roots throughout; common very fine and fine tubular pores; neutral; abrupt wavy boundary. (0 to 3 inches thick)
Btn--2 to 11 inches; dark grayish brown (2.5Y 4/2) silty clay, very dark grayish brown (2.5Y 3/2) moist; moderate coarse columnar structure parting to strong medium subangular blocky; extremely hard, extremely firm, sticky and plastic; common very fine roots between peds; common very fine tubular pores; many continuous prominent clay films on faces of peds and in pores; moderately alkaline; clear wavy boundary. (3 to 12 inches)
Btkny--11 to 19 inches; light olive brown (2.5Y 5/3) silty clay, olive brown (2.5Y 4/3) moist; moderate coarse prismatic structure parting to moderate medium subangular blocky; hard, firm, sticky and plastic; common very fine roots between peds; common very fine tubular pores; common discontinuous distinct clay films on faces on vertical and horizontal faces of peds; common fine irregular masses of gypsum; common fine irregular masses of lime; violently effervescent; strongly alkaline; gradual wavy boundary. (5 to 40 inches)
Bky--19 to 29 inches; grayish brown (2.5Y 5/2) silty clay loam, dark grayish brown (2.5Y 4/2) moist; moderate medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; common very fine roots throughout; common very fine tubular pores; common fine irregular masses of gypsum; common fine irregular masses of lime; violently effervescent; strongly alkaline; gradual wavy boundary. (0 to 30 inches)
Bk--29 to 44 inches; light brownish gray (2.5Y 6/2) silty clay, grayish brown (2.5Y 5/2) moist; weak fine and medium subangular blocky structure; hard, firm, sticky and plastic; few very fine tubular pores; common fine irregular masses of lime; violently effervescent; strongly alkaline; gradual wavy boundary. (0 to 20 inches)
C--44 to 80 inches; light brownish gray (2.5Y 6/2) silt loam, grayish brown (2.5Y 5/2) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine tubular pores; strongly effervescent; strongly alkaline.
TYPE LOCATION: Billings County, North Dakota. 590 feet north and 710 feet west of the southeast corner of section 29, T. 137 N., R. 100 W.
RANGE IN CHARACTERISTICS:
Soil Temperature - 40 to 45 degrees F.
Mollic Thickness - 7 to 16 inches after mixing
Depth to Visible Salts - 5 to 16 inches
A horizon - some uncultivated pedons have a thin A horizon
Combined thickness of A and E horizons - 1 to 5 inches
E horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 (3 or 4 moist)
Chroma: 2 or 3
Texture: loam or silt loam
Clay content: 15 to 27 percent
Reaction: slightly acid or neutral
Btn horizon - 2.5Y or 10YR
Value: 4 or 5 (3 moist)
Chroma: 2 or 3
Texture: silty clay, clay, silty clay loam or clay loam
Clay content: 35 to 50 percent
Reaction: slightly alkaline to strongly alkaline
Some pedons have a Btkn horizon.
Btkny horizon - 2.5Y, 5Y or 10YR
Value: 5 or 7 (4 or 5 moist)
Chroma: 2 to 4
Texture: silty clay, silty clay loam, clay loam or clay
Clay content: 35 to 45 percent
Reaction: slightly alkaline to strongly alkaline
Bky horizon - 2.5Y or 5Y
Value: 5 or 6 (4 or 5 moist)
Chroma: 2 or 3
Texture: silty clay loam, clay loam or silty clay
Clay content: 27 to 45 percent
Reaction: slightly alkaline to strongly alkaline
C horizon - 2.5Y, 5Y or 10YR
Value: 6 or 7 (4 or 5 moist)
Chroma: 2 to 4
Texture: silt loam, loam, sandy loam, silty clay loam, silty clay or clay
Clay content: 15 to 45 percent
Reaction: slightly alkaline to strongly alkaline
Some pedons have a BC or Cy horizon.
COMPETING SERIES: There are no competing series in the same family.
GEOGRAPHIC SETTING:
Landform - fans or flats on uplands
Elevation - 2,000 to 4,000 feet
Slope- 0 to 9 percent
Parent material - alluvium
Climate - cool, with long, cold winters; moist springs; warm summers.
Mean annual precipitation - 14 to 16 inches
Mean annual air temperature - 39 to 45 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kirby, Kremlin, Maltese, Patent and Scairt soils. Kirby soils are on hills of uplands. They have fractured or shattered porcelanite at depths of 11 to 20 inches. Kremlin and Patent soils are on fans. They are fine-loamy and do not have a natric horizon. Maltese and Scairt soils occupy similar landscape positions as the Gerda soils. Maltese soils have visible salts below a depth of 16 inches and are on micro-highs. Scairt soils have soft bedrock at depths of 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; very slow permeability; runoff is negligible to very high depending on slope.
USE AND VEGETATION: The Gerda soils are used as rangeland. The native vegetation is western wheatgrass, green needlegrass, inland saltgrass, and Nuttall saltbush.
DISTRIBUTION AND EXTENT: These soils are of moderate extent in southwestern North Dakota and possibly northwestern South Dakota and southeastern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Billings County, North Dakota, 05/2000.
REMARKS: Diagnostic horizons and features in this pedon: mollic epipedon - the zone from the surface of the soil to a depth of 11 inches after mixing the upper 7 inches (E and Btn horizons); natric horizon - the zone from 2 to 19 inches (Btn and Btkny horizons).