LOCATION ORWET                   NE+SD

Established Series
Rev. LGR
03/2020

ORWET SERIES

The Orwet series consists of very deep, poorly drained soils formed in stratified sandy alluvium on flood plains. Permeability is rapid. Slopes range from 0 to 2 percent. The mean annual precipitation is about 24 inches, and the mean annual temperature is about 48 degrees F.

TAXONOMIC CLASS: Sandy, mesic Typic Calciaquolls

TYPICAL PEDON: Orwet loam - native meadow. (Colors are for moist soil unless otherwise stated.)

Ak--0 to 18 inches; black (10YR 2/1) loam, gray (N 5/0) dry; moderate fine and very fine granular structure; slightly hard, friable; moderately alkaline; violent effervescence, 20 percent calcium carbonate equivalent; clear smooth boundary. (10 to 20 inches thick)

AC--18 to 24 inches; dark gray (5Y 4/1) loamy sand, gray (5Y 5/1) dry; weak fine and very fine granular structure; soft, very friable; few fine faint yellowish brown (10YR 5/6) iron masses in the matrix; neutral; gradual smooth boundary. (0 to 10 inches thick)

C1--24 to 46 inches; gray (5Y 5/1) sand, gray (5Y 6/1) dry; single grain; loose; common medium distinct yellowish brown (10YR 5/6) and many, small reddish brown (5YR 5/4) iron masses in the matrix; neutral; diffuse smooth boundary. (20 to 40 inches thick)

C2--46 to 60 inches; gray (5Y 5/1) sand, gray (5Y 6/1) dry; single grain; loose; many medium prominent yellow (10YR 7/6) and reddish brown (5YR 5/4) iron masses in the matrix; neutral.

TYPE LOCATION: Pierce County, Nebraska; about 2 miles west and 1 mile north of Foster; 570 feet west and 240 feet south of the northeast corner, sec. 30, T. 27 N., R. 3 W.

RANGE IN CHARACTERISTICS: The thickness of the mollic epipedon ranges from 10 to 20 inches. Free carbonates extend to depths of 10 to 30 inches. The calcium carbonate equivalent ranges from 15 to 28 percent and, in some pedons, the AC horizon contains free carbonates.

The Ak horizon has hue of 10YR or 2.5Y, value of 2 or 3 and 3 through 5 dry, and chroma of 0 to 1. It typically is a loam but the range includes sandy loam, fine sandy loam or silt loam. It is slightly alkaline or moderately alkaline.

The AC horizon has faint or distinct redoximorphic features ranging from reddish yellow to yellowish brown. It typically is loamy fine sand or loamy sand but range includes fine sandy loam or sand. It is neutral in horizons lacking free carbonates and moderately alkaline where there are free carbonates.

The C horizon has hue of 10YR, 2.5Y or 5Y, value of 5 or 6 and 6 or 7 dry, and chroma of 1 or 2. Redoximorphic features are distinct or prominent and range from dark brown to yellow. Common reddish brown masses of iron-manganese are throughout the C horizon. The C horizon commonly is sand but ranges from loamy fine sand to sand. Thin stratified finer textured sediments are in some pedons.

COMPETING SERIES: There are no other series in the same family.

GEOGRAPHIC SETTING: Orwet soils formed in stratified sandy alluvium on flood plains. Slopes range from 0 to 2 percent. Mean annual temperature ranges from 47 to 50 degrees F, and mean annual precipitation ranges from 20 to 24 inches.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Elsmere, Lawet, Leshara, Loup, Ord, and Ovina soils. The Elsmere, Leshara, Ord, and Ovina soils lack calcic horizons and have lower water tables during the growing season. Elsmere and Ovina soils are on slightly higher landscapes and Ovina soils are coarse-loamy. Leshara soils are fine-silty and on similar landscapes. Ord soils are fine-loamy and Loup soils lack calcic horizons and both are on similar positions on the landscape.

DRAINAGE AND PERMEABILITY: Orwet soils are poorly drained. Runoff is slow. Permeability is rapid. These soils rarely flood. Depth to the seasonal high water table ranges from 1 to 2 feet.

USE AND VEGETATION: Mostly in meadows and pasture. Native vegetation when in excellent condition, is mainly big bluestem, switchgrass, indiangrass, prairie cordgrass, and tall sedges. Where drained small areas are used as cropland.

DISTRIBUTION AND EXTENT: Northeast Nebraska and southeastern South Dakota. The series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota

SERIES ESTABLISHED: Pierce County, Nebraska, 1970.

REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon--the zone from the surface to a depth of approximately 18 inches (Ak horizon); calcic horizon--0 to 18 inches (Ak horizon); and aquic condition--redoximorphic features were at a depth of 18 to 60 inches.

The Orwet soils now include the poorly drained soils with calcic horizons formerly included in the Ord and Wann series.

In Nebraska, the native vegetative cover is an herbaceous wetland community commonly inhabited with sedges (Carex emoryi, C. laeviconica, C. pellita, C. vulpinoidea), flat stem spikerush, (Eleocharis compressa), Kentucky bluegrass (Poa Pratensis), prairie cordgrass (Spartina pectinate). Source: Terrestrial Ecological Systems and Natural Communities of Nebraska, Version IV. S.B. Rolfsmeier and G. Steinauer. Nebraska Natural Heritage Program, Nebraska Game and Parks Commission. 2010

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National Cooperative Soil Survey
U.S.A.