LOCATION NAPA SD+IA NE
Established Series
Rev. JLD-RAL-GHC
04/2020
NAPA SERIES
The Napa series consists of very deep, poorly drained and very poorly drained, very slowly permeable soils that formed in clayey alluvium. These soils occur on flood plains and stream terraces. Slope ranges from 0 to 2 percent. Mean annual precipitation is about 690 millimeters (27 inches) and mean annual air temperature is about 10 degrees C (50 degrees F)at the type location.
TAXONOMIC CLASS: Fine, smectitic, mesic Typic Natraquerts
TYPICAL PEDON: Napa silt loam, on a level slope of less than one percent, in grass. (Colors are for moist soils unless otherwise stated.)
E--0 to 1.5 centimeters (0 to 0.5 inches); very dark gray (10YR 3/1) silt loam, gray (10YR 6/1) dry; weak thin platy structure; hard, friable, slightly sticky and slightly plastic; many very fine and few fine roots; few fine vesicular and tubular pores; slightly alkaline; abrupt smooth boundary. (1 to 2.5 centimeters (1/8 to 1 inch) thick)
Btnz1--1.5 to 18 centimeters (0.5 to 7 inches); black (2.5Y 2.5/1) silty clay, dark gray (2.5Y 4/1) dry; weak coarse and moderate medium columnar structure parting to moderate medium subangular blocky; very hard, firm, sticky and plastic; many very fine and few fine roots; common very fine vesicular and tubular pores; common tonguing of E horizon on tops of columns; common fine nests of gypsum and common fine threads of salt; moderately alkaline; clear smooth boundary.
Btnz2--18 to 43 centimeters (7 to 17 inches); black (2.5Y 2.5/1) silty clay, dark gray (2.5Y 4/1) dry; weak coarse subangular blocky structure parting to moderate medium subangular blocky; very hard, firm, sticky and plastic; common very fine roots; common very fine vesicular and tubular pores; common fine and medium nests of gypsum and few fine threads of salt; moderately alkaline; clear smooth boundary. (Combined thickness of the Btnz horizons is 15 to 61 centimeters (6 to 24 inches)
Btnzg1--43 to 66 centimeters (17 to 26 inches); very dark gray (5Y 3/1) and black (5Y 2.5/1) silty clay, dark gray (5Y 4/1) and gray (5Y 5/1) dry; weak coarse subangular blocky structure parting to moderate medium subangular blocky; very hard, firm, sticky and plastic; few very fine roots; common very fine vesicular and tubular pores; common fine and medium nests of gypsum and few fine threads of salt; few fine prominent dark yellowish brown (10YR 4/6) redoximorphic concentrations; slightly effervescent; moderately alkaline; clear smooth boundary.
Btnzg2--66 to 84 centimeters (26 to 33 inches); very dark gray (5Y 3/1) silty clay, gray (5Y 5/1) dry; weak coarse subangular blocky structure parting to moderate medium subangular blocky; very hard, firm, sticky and plastic; few very fine roots; common very fine vesicular and tubular pores; common fine and medium nests of gypsum and other salts; common fine prominent dark yellowish brown (10YR 4/6) redoximorphic concentrations; slightly effervescent; moderately alkaline; abrupt smooth boundary. (Combined thickness of the Btnzg horizons is 25 to 89 centimeters (10 to 35 inches).
Bksszg1--84 to 124 centimeters (33 to 49 inches); dark gray (5Y 4/1) silty clay, gray (5Y 6/1) dry; weak medium subangular blocky structure; very hard, firm, sticky and plastic; few very fine roots between peds; common very fine vesicular and tubular pores; few black (N 2/0) streaks 1 to 3 mm thick; common to many prominent intersecting slickensides; common fine and medium nests of gypsum and other salts; few fine iron- manganese concretions, few fine and medium manganese concretions coated with hard masses of carbonate; common fine and medium soft masses of carbonate; many fine and common medium prominent dark yellowish brown (10YR 4/6) redoximorphic concentrations; strongly effervescent; moderately alkaline; gradual wavy boundary.
Bksszg2--124 to 168 centimeters (49 to 66 inches); dark gray (5Y 4/1) silty clay, gray (5Y 6/1) dry; weak medium subangular blocky structure; very hard, firm, sticky and plastic; few very fine roots between peds; common very fine vesicular and tubular pores; common to many prominent intersecting slickensides; common fine and medium nests of gypsum and other salts; few fine and medium iron-manganese concretions; common fine soft masses of carbonate; many fine and medium prominent dark yellowish brown (10YR 4/6) redoximorphic concentrations; strongly effervescent; moderately alkaline; abrupt smooth boundary. (Combined thickness of the Bksszg horizons is 25 to 112 centimeters (10 to 44 inches)
Ayssgb--168 to 200 centimeters (66 to 80 inches); very dark gray (5Y 3/1) silty clay, dark gray (5Y 4/1) dry; weak medium subangular blocky structure; very hard, firm, sticky and plastic; common very fine vesicular and tubular pores; few prominent nonintersecting slickensides; common fine and medium nests of gypsum with coats of soft masses of carbonate; few fine carbonate concretions; few fine prominent dark yellowish brown (10YR 4/4) redoximorphic concentrations; strongly effervescent; moderately alkaline. (Thickness of Ayssgb horizon is 0 to 38 centimeters (0 to 15 inches) thick)
TYPE LOCATION: Clay County, South Dakota; about 2.4 kilometers (1.5 miles) north and 2.4 kilometers (1.5 miles) west of Meckling; located about 427 meters (1,400 feet) north and 32 meters (105 feet) east of the southwest corner of sec. 15, T. 93 N., R. 53 W.; USGS Meckling quadrangle; lat. 42 degrees 52 minutes 13 seconds N. and long. 97 degrees 06 minutes 06 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Depth to nests of salts and gypsum: 1 to 41 centimeters (1/8 to 16 inches)
Depth to carbonates: 13 to 114 centimeters (5 to 45 inches)
Thickness of the mollic epipedon: 51 to 127 centimeters (20 to 50 inches)
Particle-size control section (weighted average):
Clay content: 45 to 60 percent
Sand content: 1 to 5 percent fine sand and coarser than fine sand
Ap horizon (if it occurs):
Hue: 10YR, 2.5Y, or is neutral
Value: 2 or 3
Chroma: 0 or 1
Texture: silty clay or clay
Clay content: 40 to 60 percent
Sand content: 1 to 8 percent
Calcium carbonate equivalent: 0 to 10 percent
Reaction: slightly acid to slightly alkaline
Note: Some pedons may have an Ap horizon incorporating the E and upper Btnz horizon
E horizon:
Hue: 10YR
Value: 3 or 4, 5 to 7 dry
Chroma: 1
Texture: silt loam or silty clay loam
Clay content: 15 to 35 percent
Sand content: 1 to 8 percent
Calcium carbonate equivalent: 0 to 5 percent
Reaction: neutral to moderately alkaline
Btnz, Btnzg, Btnyssg, or Btnysszg horizon:
Hue: 10YR, 2.5Y, 5Y, or is neutral
Value: 2 to 5, 3 to 7 dry
Chroma: 0 or 1
Texture: clay or silty clay
Clay content: 45 to 60 percent
Sand content: 1 to 5 percent
Calcium carbonate equivalent: 0 to 15 percent
Reaction: slightly alkaline to strongly alkaline
These horizons have few or common nests of salts
Bksszg horizon:
Hue: 2.5Y or 5Y
Value: 3 to 5, 5 to 7 dry
Chroma: 1 or 2
Texture: clay, silty clay, or silty clay loam
Clay content: 27 to 60 percent
Sand content: 1 to 20 percent
Calcium carbonate equivalent: 5 to 25 percent
Reaction: slightly alkaline to strongly alkaline
This horizon has few to many, faint to prominent redoximorphic features, few to common accumulations of carbonate, and few to common nests of gypsum and other salts
Ayssgb horizon (if it occurs):
Hue: 2.5Y or 5Y
Value: 2 or 3, 3 to 5 dry
Chroma: 1 or 2
Texture: clay, silty clay, or silty clay loam
Clay content: 27 to 60 percent
Calcium carbonate equivalent: 0 to 25 percent
Reaction: slightly to strongly alkaline
This horizon has few to many, faint to prominent redoximorphic features, few to common accumulations of carbonate, and few to common nests of gypsum and other salts
Cyzg horizon (if it occurs):
Hue: 2.5Y or 5Y
Value: 4 to 6, 6 to 8 dry
Chroma: 1 or 2
Texture: clay, silty clay, or silty clay loam
Clay content: 27 to 60 percent
Sand content: 1 to 20 percent
Calcium carbonate equivalent: 0 to 25 percent
Reaction: slightly alkaline to strongly alkaline
This horizon has few to many, faint to prominent redoximorphic features, few to common accumulations of carbonate, and few to common nests of gypsum and other salts
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Parent material: clayey alluvium
Landform: flood plains and stream terraces
Slope: 0 to 2 percent
Elevation: 274 to 457 meters (900 to 1,500 feet) above sea level
Mean annual air temperature: 7 to 13 degrees C (45 to 55 degrees F)
Mean annual precipitation: 460 to 910 millimeters (18 to 36 inches)
Frost-free period: 130 to 190 days
GEOGRAPHICALLY ASSOCIATED SOILS:
These are the
Blencoe,
Gayville,
James,
Lamo,
Luton,
Onawa, and
Salmo soils.
Blencoe: are in the slightly higher landscape positions, have a clay content of 18 to 24 percent in the lower half of the series control section, and do not have a natric horizon
Gayville: are in the slightly higher landscape positions and have a clay content of 35 to 45 percent in the particle-size control section
James: are in landscape positions similar to the Napa soils, have buried horizons within a depth of 152 centimeters (60 inches), and do not have a natric horizon
Lamo: are in the slightly higher landscape positions and do not have a natric horizon
Luton: are in landscape positions similar to the Napa soils, have a depth to carbonates range of 38 to 91 centimeters (15 to 36 inches), and do not have a natric horizon
Onawa: are in the slightly higher landscape positions, have a clay content of 10 to 18 percent in the lower two thirds of the series control section, and do not have a natric horizon
Salmo: are in landscape positions similar to the Napa soils, have a clay content of less than 45 percent in the particle-size control section, and do not have a natric horizon
DRAINAGE AND PERMEABILITY:
Drainage class: poorly and very poorly drained; these soils are frequently saturated at the soil surface during the wettest portions of normal years and is considered perched
Permeability: very slow
Surface runoff potential: low or negligible
Flooding: rarely or occasionally flooded for very brief or brief periods during the months of February to November from precipitation events and snowmelt
Ponding: some areas are ponded for very brief or brief periods during the months of February to November from precipitation events and snowmelt
USE AND VEGETATION:
Most areas are in rangeland or hayland. The native vegetation includes cordgrass, western wheatgrass, nuttall alkaligrass, saltgrass and perennial forbs. See Additional Data section for native vegetative cover in Iowa and Nebraska.
DISTRIBUTION AND EXTENT:
LRR M, MLRAs 53C, 55C, 102B, 102C and 107; southeast South Dakota, Iowa, and Nebraska. This series is of small extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Salina, Kansas.
SERIES ESTABLISHED: Clay County, South Dakota, 1953.
REMARKS:
Particle-size control section: the zone from 1.25 to 51 centimeters (0.5 to 20 inches) (Btnz1, Btnz2, and Btnzg1 horizons);
Series control section: the zone from the surface to a depth of 203 centimeters (80 inches) (E, Btnz1, Btnz2, Btnzg1, Btnzg2, Bksszg1, Bksszg2, and Ayssgb horizons).
Diagnostic horizons and features recognized in this pedon:
Mollic epipedon: the zone from the surface to a depth of about 84 centimeters (33 inches) (E, Btnz1, Btnz2, Btnzg1, and Btnzg2 horizons).
Argillic (Natric) horizon: the zone from about 2.5 to 84 centimeters (1 inch to 33 inches) (Btnz1, Btnz2, Btnzg1, and Btnzg2 horizons);
Buried horizon: the zone from 168 to 203 centimeters (66 to 80 inches) (Ayssgb horizon);
Moisture regime: aquic
Taxonomy version: Second Edition, 1999.
ADDITIONAL DATA:
Laboratory data--National Soil Survey Laboratory, Lincoln, Nebraska pedon S93SD-027-072 (http://ssldata.nrcs.usda.gov/).
In Iowa, the native vegetative cover is an herbaceous wetland community commonly inhabited with Prairie Cordgrasses, Big Bluestems, Switchgrasses, Grays Sedges, Fox Sedges, Tall Tickseeds, and Great St. John Worts. Source: Iowa State Office, Natural Resources Conservation Service, Des Moines, IA.
In Nebraska, the native vegetative cover is an herbaceous wetland community commonly inhabited with inland saltgrass (Distichlis spicata), foxtail barley (Hordeum jubatum), annual marsh-elder (Iva annua), Plains bluegrass (Poa arida), saltwort (Salicornia rubra), prairie cordgrass (Spartina pectinata), seablite (Suaeda calceoliformis). 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.