LOCATION NISHNA             IA+MN NE

NISHNA SERIES

TAXONOMIC CLASS: Fine, smectitic, calcareous, mesic Cumulic Vertic Endoaquolls

TYPICAL PEDON: Nishna silty clay, with a slope of less than 1 percent, on a flood plain, at an elevation of about 293 meters above mean sea level, in a cultivated field. (All colors are for moist soil unless otherwise stated.)

Ap--0 to 18 centimeters; black (10YR 2/1) silty clay, very dark gray (10YR 3/1) dry; moderate medium subangular blocky structure parting to weak fine granular; friable; very few silt coats of grayish brown (10YR 5/2) dry; many roots; many pores; neutral; clear smooth boundary.

A1--18 to 41 centimeters; black (N 2/0) silty clay, very dark gray (N 3/0) dry; moderate fine subangular blocky structure; firm; sheen on faces of peds; many roots; many fine pores; slightly effervescent; slightly alkaline; clear smooth boundary.

A2--41 to 66 centimeters; black (10YR 2/1) silty clay, very dark gray (10YR 3/1) dry; moderate medium and fine subangular blocky structure; firm; few roots; few fine pores; gray lime flecks and small lime concretions; slightly effervescent; moderately alkaline; clear smooth boundary.

Bkg--66 to 91 centimeters; very dark gray (N 3/0) silty clay, dark gray (N 4/0) dry; moderate fine subangular blocky structure; firm; few roots; few fine pores; many soft and hard small lime accumulations; slightly effervescent; moderately alkaline; clear smooth boundary.

Cg--91 to 152 centimeters; dark gray (5Y 4/1) silty clay; very weak fine subangular blocky structure grading to massive; firm; few fine roots; few fine pores; many soft and hard lime accumulations; strongly effervescent; moderately alkaline.

TYPE LOCATION: Major Land Resource Area (MLRA) 107B - Iowa and Missouri Deep Loess Hills; Fremont County, Iowa subset; about 1 1/2 miles west and 1 mile north of Randolph; located about 1,320 feet east and 1,320 feet north of the southwest corner of section 5, T. 70 N., R. 41 W.; USGS Tabor NE topographic quadrangle; latitude 40 degrees 53 minutes 30 seconds N. and longitude 95 degrees 35 minutes 23 seconds W., NAD 83.

RANGE IN CHARACTERISTICS:
Mollic epipedon thickness--60 to more than 152 centimeters.
Sand content throughout-0 to 15 percent
Clay content (particle-size control section)-35 to 46 percent
This soil has carbonates throughout, except Ap horizons are usually leached of carbonates
Depth to redoximorphic concentrations (if present)--greater than 90 centimeters
Some pedons have snail shell fragments.
Depth to silt or sand stratification (if present)-greater than 120 centimeters
Electrical conductivity--0 mmhos/cm
Gypsum content--0 percent

A horizon:
Hue--10YR or neutral
Value--2 or 3
Chroma--0 or 1
Texture--silty clay loam or silty clay
Clay content--35 to 45 percent
Calcium carbonate equivalent--0 to 30 percent
Reaction--pH 7.4 to 8.4 (slightly alkaline or moderately alkaline); Ap horizons are pH 6.6 to 8.4 (neutral to moderately alkaline)
Moist bulk density--1.25 to 1.35 g/cc
Thickness--46 to 150 centimeters
In overwash phases, a texture of silt loam with clay content of 20 to 27 percent is within the range of characteristics.

Some pedons have a buried soil at a depth of 45 to 90 centimeters

Bg horizon (if present):
Hue--10YR, 2.5Y, 5Y, or is neutral
Value--3 or 4
Chroma--0 or 1
Texture--silty clay
Clay content--40 to 50 percent
Calcium carbonate equivalent--5 to 30 percent
Reaction--slightly alkaline or moderately alkaline
Moist bulk density--1.30 to 1.40 g/cc
Thickness--15 to 45 centimeters

Bkg horizon:
Hue--10YR, 2.5Y, 5Y, or neutral
Value-3 or 4
Chroma--0 or 1
Clay content--38 to 50 percent
Calcium carbonate equivalent--5 to 30 percent
Reaction--pH 7.4 to 8.4 (slightly alkaline or moderately alkaline)
Moist bulk density--1.30 to 1.40 g/cc
Thickness--15 to 56 centimeters

Cg horizon:
Hue10YR, 2.5Y, 5Y or neutral
Value--3 or 4
Chroma--0 or 1
Texture--silty clay or clay
Clay content--50 to 60 percent
Calcium carbonate equivalent--5 to 30 percent
Reaction--pH 7.4 to 7.4 (slightly alkaline or moderately alkaline)
Moist bulk density--1.35 to 1.45 g/cc

COMPETING SERIES: These are the Baltic, Delvada, James, and Knoke.
Baltic--have gypsum above 100 centimeters.
Delvada--have salinity throughout with measured electrical conductivity of 2 to 32 mmhos/cm.
James--have visible salts and an electrical conductivity of 8 to 20 mmhos/cm.
Knoke--have sand content of 15 to 30 percent in the 25 to 100 centimeter particle-size control section.

GEOGRAPHIC SETTING:
Parent material-alluvium
Landform-flood plain; back swamp positions often some distance from the main stream channel
Slope--0 to 2 percent
Elevation--185 to 335 meters above mean sea level
Mean annual air temperature--4 to 13 degrees C.
Mean annual precipitation--485 to 1040 millimeters
Frost-free period--140 to 220 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bremer, Calco, Colo, Marshall, Nevin, Nodaway, and Zook soils.
Bremer--are on higher landscape positions, have carbonates deeper than 152 centimeters, and are in the Argiaquolls Great Group.
Calco-have 24 to 35 percent clay in the particle-size control section and are in the Cumulic Endoaquolls Subgroup.
Colo--are on higher landscape positions, have carbonates deeper than 150 centimeters, and are in the Cumulic Endoaquolls Subgroup.
Marshall--are formed in loess on adjacent side slopes of uplands and stream terraces.
Nevin--are on higher landscape positions, have carbonates deeper than 150 centimeters, have 30 to 35 percent clay in the particle-size control section, and are in the Argiudolls Great Group.
Nodaway--are on higher landscape positions and are in the fine-silty particle-size class.
Zook--are on higher landscape positions and have carbonates at 150 to more than 200 centimeters

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage-water saturation occurs between 0 to 30 centimeters from March through June in years with normal precipitation (when precipitation is within one standard deviation of the 30-year mean of annual precipitation) (poorly drained). This saturation is considered apparent.
Ponding-up to 30 centimeters deep (very poorly drained)
Saturated Hydraulic Conductivity-0.01 to 0.10 micrometers per second.
Flooding--occasional (5 to 50 percent chance) or rare (1 to 5 percent chance) for brief periods (2 to 7 days)

USE AND VEGETATION: Native vegetation includes prairie cordgrass, sedges, river bulrush and other species of the tall grass prairie that are tolerant of wetness. Corn and soybeans are the principal crops when adequate drainage is possible. Some small grain and hay is also grown.

DISTRIBUTION AND EXTENT:
Physiographic Division-Interior Plains
Physiographic Province-Central Lowland
Physiographic Sections-Western Lake; Dissected Till Plains
Land Resource Region-Central Feed Grains and Livestock Region (M)
Major land Resource Areas:
-Rolling Till Prairie (102A)
-Loess Uplands (102C)
-Central Iowa and Minnesota Till Prairies (103)
-Nebraska and Kansas Loess-Drift Hills (106)
-Iowa and Minnesota Loess Hills (107A)
--Iowa and Missouri Deep Loess Hills (107B)

Extent-moderate; 11,115 hectares (27,454 acres) have been correlated.

MLRA OFFICE RESPONSIBLE: MLRA Soil Survey Regional Office 10 (St. Paul, Minnesota); MLRA Soil Survey Office 10-6 (Atlantic, Iowa).

SERIES ESTABLISHED: Fremont County, Iowa, 1974.

REMARKS: Diagnostic horizons and features recognized in the Typical Pedon include:
Control sections:
--Soil moisture-10 to 30 centimeters
--Particle-size--25 to 100 centimeters
--Mineralogy class-25 to 100 centimeters
--Cation-Exchange activity class-25 to 100 centimeters
--Calcareous and reaction class-25 to 50 centimeters
--Soil Temperature-50 centimeters
--Series-0 to 150 centimeters
Mollic epipedon--0 to 91 centimeters (Ap, A1, A2 and Bkg horizons)
Aquic conditions:
--Endosaturation-0 to 152 centimeters
--Reduced matrix-66 to 152 centimeters
Soil moisture regime--aquic
Soil temperature regimemesic

Vertic subgroup based on linear extensibility greater than 6.0 centimeters between the surface and a depth of 100 centimeters.

Taxonomy version--Keys to Soil Taxonomy, tenth edition, 2006.