LOCATION LAWET NE+SD

Established Series
Rev. MK-RRZ-GHC
03/2020

LAWET SERIES

The Lawet series consists of very deep, poorly drained and very poorly drained soils formed in loamy alluvium on flood plains. Permeability is moderate or moderately slow. Slopes range from 0 to 2 percent. The mean annual precipitation is about 660 millimeters (26 inches), and the mean annual air temperature is about 9 degrees C (49 degrees F) at the type location.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Typic Calciaquolls

TYPICAL PEDON: Lawet loam with a slope of less than 2 percent in a native meadow. (Colors are for dry soil unless otherwise stated.)

Ak--0 to 25 centimeters (0 to 10 inches); dark gray (N 4/0) loam, black (10YR 2/1) moist, moderate fine and very fine granular structure; slightly hard, friable; violent effervescence (18 percent calcium carbonate equivalent); moderately alkaline; clear smooth boundary. (18 to 36 centimeters (7 to 14 inches) thick)

ABk--25 to 46 centimeters (10 to 18 inches); gray (N 5/0) sandy clay loam, very dark gray (10YR 3/1) moist, moderate fine and very fine granular structure; hard, firm; violent effervescence (20 percent calcium carbonate equivalent); moderately alkaline; gradual smooth boundary. (8 to 25 centimeters (3 to 10 inches) thick)

Bk1--46 to 64 centimeters (18 to 25 inches); gray (N 6/0) sandy clay loam, dark gray (10YR 4/1) moist, moderate fine and very fine granular structure; hard, firm; violent effervescence (20 percent calcium carbonate equivalent); moderately alkaline; clear smooth boundary.

Bk2--64 to 79 centimeters (25 to 31 inches); gray (5Y 6/1) sandy loam, gray (5Y 5/1) moist, moderate and weak very fine granular structure; slightly hard, very friable; violent effervescence (12 percent calcium carbonate equivalent); moderately alkaline; clear smooth boundary.

Bk3--79 to 140 centimeters (31 to 55 inches); gray (5Y 6/1) sandy clay loam, gray (5Y 5/1) moist, many medium prominent reddish brown (5YR 4/4) moist mottles; weak medium and very fine subangular blocky structure; slightly hard, firm; small accumulations of lime; violent effervescence (22 percent CaC03 equivalent); moderately alkaline; gradual smooth boundary. (Combined thickness of Bk horizons is 15 to 102 centimeters (6 to 40 inches))

Cg--140 to 152 centimeters (55 to 60 inches); light olive gray (5Y 6/2) sandy loam, light greenish gray (5GY 7/1) moist, massive; slightly hard, firm; neutral.

TYPE LOCATION: Pierce County, Nebraska; about 3.2 kilometers (2 miles) west and 3.2 kilometers (2 miles) north of Foster; 649 meters (2130 feet) south and 40 meters (130 feet) west of the northeast corner, section 19, T. 27 N., R. 3 W.

RANGE IN CHARACTERISTICS:
Soil moisture: Lawet soils are saturated in most parts of the soil moisture control section. They are moist in some part of the soil moisture control section for more than 90 cumulative days in the 120 days following the summer solstice.
Depth to secondary carbonates: Typically, at or very near the surface of the soil
Depth to redoximorphic features: Iron concentration which are distinct or prominent with hues of 5YR or 7.5YR, value of 3 to 5, and chroma of 3 to 6 are above 102 centimeters (40 inches)
Depth to endosaturation: 0 to 61 centimeters (0 to 24 inches) from surface of the soil
Thickness of the mollic epipedon: 18 to 61 centimeters (7 to 24 inches)
Thickness of the solum: 41 to 140 centimeters (16 to 55 inches)

A horizon:
Hue: 10YR, 2.5Y or Neutral
Value: 3 to 5 dry, 2 or 3 moist
Chroma: 0 or 1
Texture: typically loam and less commonly very fine sandy loam, fine sandy loam, sandy clay loam, silt loam, and silty clay loam
Calcium carbonate equivalent: typically, 15 to 40 percent, however within 38 centimeters (15 inches) of the soil surface the calcium carbonate may be as low as 12 percent in some pedons.
Reaction: slightly alkaline or moderately alkaline

Bk horizon:
Hue: 10YR, 5Y, 2.5Y or Neutral
Value: 5 to 7 dry, 4 or 5 moist
Chroma: 0 to 2
Texture: sandy clay loam, clay loam, loam, very fine sandy loam, or silty clay loam
Calcium carbonate equivalent: 15 to 40 percent
Reaction: slightly alkaline or moderately alkaline

Cg horizon:
Hue: 10YR, 2.5Y, 5Y, 5GY, or neutral
Value: 5 to 7 dry, 4 to 7 moist
Chroma: 0 to 2
Texture: sandy clay loam, loam, clay loam, sandy loam, or very fine sandy loam; coarse textured strata, that contain smaller amounts of calcium carbonate than the finer textured strata, are below a depth of 102 centimeters (40 inches) in some pedons
Reaction: neutral to moderately alkaline

COMPETING SERIES: These are the Harps, Revere, and Roshe Springs series in the same family.
Harps soils have thicker sola and formed in glacial till.
Revere soils have less sand in the lower half of the series control section and are formed in glacial till.
Roshe Springs soils have a calcium carbonate equivalent ranging from 40 to 80 percent.

GEOGRAPHIC SETTING: Lawet soils are level or nearly level. They are on flood plains and commonly at the upper end of stream valleys in sand-loess transition areas. Slope gradients range from 0 to 2 percent. Lawet soils formed in loamy alluvium. The range of mean annual air temperature is 8 to 11 degrees C (47 degrees to 52 degrees F) and the range of mean annual precipitation is 460 t0 760 millimeters (18 to 30 inches).

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Coleridge, Gibbon, Lamo, Lex, Ord, and Orwet soils, which are on similar landscapes. The Coleridge, Gibbon, Lamo, Lex, and Ord soils do not have calcic horizons and are somewhat poorly drained. The Coleridge, Gibbon, and Lamo soils are in the fine-silty family. Lex soils are moderately deep over coarse sand or gravelly sand. Ord soils are in the coarse-loamy family. Orwet soils are in the sandy family.

DRAINAGE AND PERMEABILITY: Poorly drained, but some areas are very poorly drained. Runoff is slow. Permeability is moderate or moderately slow. The seasonal high-water table in the poorly drained soil ranges from a depth of 0 to 61 centimeters (0 to 24 inches).

USE AND VEGETATION: Lawet soils are mostly in meadow and pasture. Native vegetation, when in excellent condition, is mainly big bluestem, little bluestem, switchgrass, indiangrass, and prairie cordgrass. Small areas are used as cropland, but in many areas, adequate drainage is difficult to provide. See Remarks section for native vegetative cover in Nebraska.

DISTRIBUTION AND EXTENT: Nebraska. The series is moderately extensive.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Salina, Kansas.

SERIES ESTABLISHED: Pierce County, Nebraska, 1970.

REMARKS: Lawet soils were previously mapped in the Gibbon, Lamo, and Leshara series. A somewhat poorly drained phase has been mapped and will need future investigations for possible new series. Phases recognized to date include drained, wet, ponded, and saline-alkali.

OSD modification RRZ 7/2002: Within 38 centimeters (15 inches) of the soil surface the calcium carbonate equivalent may be as low as 12 percent.

Diagnostic horizons and features recognized in this pedon are:
mollic epipedon--the zone from the surface of the soil to a depth of about 46 centimeters (18 inches) (Ak and ABk horizons)
calcic horizon--the zone from surface of the soil to about 140 centimeters (55 inches) (Ak, ABk, Bk1, Bk2, and Bk3 horizons).

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

National Cooperative Soil Survey
U.S.A.