LOCATION NAPIER                  IA+MO NE

Established Series
Rev. FFR-JFH-JRH
09/2016

NAPIER SERIES

The Napier series consists of very deep, well drained soils on foot slopes, upland drainageways, and alluvial fans. These soils formed in local colluvium and alluvium derived from loess. Slopes range from 0 to 20 percent. Mean annual air temperature is about 11 degrees C. Mean annual precipitation is about 790 millimeters.

TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Cumulic Hapludolls

TYPICAL PEDON: Napier silt loam, on a 3 percent slope, in a cultivated field, at an elevation of 312 meters (1,025 feet) above sea level. (Colors are for moist soil unless otherwise noted.)

Ap--0 to 20 centimeters; very dark brown (10YR 2/2) silt loam, very dark grayish brown (10YR 3/2) dry; moderate fine granular structure; friable; many roots and pores; slightly acid to neutral; gradual smooth boundary.

A--20 to 74 centimeters; very dark brown (10YR 2/2) silt loam, very dark grayish brown (10YR 3/2) dry; weak very fine subangular blocky and fine granular structure; friable; many roots and pores; many root channels and worm casts; neutral; gradual smooth boundary. (Combined thickness of the A horizon is 46 to 86 centimeters.)

BA--74 to 94 centimeters; dark brown (10YR 3/3) silt loam, brown (10YR 5/3) dry; weak very fine subangular blocky and fine granular structure; friable; few fine roots; many pores; few worm casts; few very dark brown (10YR 2/2) coats on surfaces along root channels; neutral; diffuse smooth boundary. (0 to 30 centimeters thick)

Bw--94 to 122 centimeters; brown (10YR 4/3) silt loam; weak very fine subangular blocky structure; very friable; few roots; many pores; some dark brown (10YR 3/3) worm casts and organic coats; neutral; diffuse smooth boundary. (15 to 102 centimeters thick)

C--122 to 152 centimeters; brown (10YR 4/3) silt loam; massive; very friable; slightly effervescent in the lower part; slightly alkaline.

TYPE LOCATION: Major Land Resource Area (MLRA) 107B-Iowa and Missouri Deep Loess Hills, Fremont County, Iowa subset; about 1.6 kilometers (1 mile) east and 3.2 kilometers (2 miles) south of Thurman; about 598 meters (1,960 feet) south and 341 meters (1,120 feet) east of the northwest corner of section 18, T. 69 N., R. 42 W.; USGS Tabor SW quadrangle; lat. 40 degrees 46 minutes 50.51 seconds N. and long. 95 degrees 43 minutes 26.23 seconds W., WGS 84.

RANGE IN CHARACTERISTICS:
Depth to calcium carbonate--greater than 91 centimeters
Thickness of the mollic epipedon--60 to 102 centimeters
Content of clay in the particle-size control section (weighted average)--20 to 27 percent
Content of sand in the particle-size control section (weighted average)--less than 10 percent
The thickness of the mollic epipedon and depth to carbonates usually decrease with increase in slope gradient

Ap or A horizon:
Hue--10YR
Value--2 or 3
Chroma--1 or 2
Texture--silt loam
Clay content--20 to 27 percent
Sand content--less than 10 percent
Reaction--slightly acid or neutral
Moist bulk density--1.20 to 1.30 g/cc

BA horizon (when present):
Hue--10YR
Value--3
Chroma--3
Texture--silt loam
Clay content--20 to 27 percent
Sand content--less than 10 percent
Reaction--slightly acid to moderately alkaline
Moist bulk density--1.25 to 1.30 g/cc

Bw horizon:
Hue--10YR
Value--4
Chroma--3 or 4
Texture--silt loam
Clay content--20 to 27 percent
Sand content--less than 10 percent
Reaction--slightly acid to moderately alkaline
Moist bulk density--1.25 to 1.30 g/cc

In most pedons, dark organic coats mask higher chroma interior colors

Bk horizon (when present):
Hue--10YR
Value--4 or 5
Chroma--3 or 4
Texture--silt loam
Clay content--20 to 27 percent
Sand content--less than 10 percent
Reaction--slightly alkaline or moderately alkaline
Moist bulk density--1.25 to 1.30 g/cc

C horizon:
Hue--10YR
Value--4 or 5
Chroma--3 or 4
Texture--silt loam
Clay content--20 to 27 percent
Sand content--less than 10 percent
Reaction--slightly acid to moderately alkaline
Moist bulk density--1.25 to 1.30 g/cc

COMPETING SERIES: These are the Allison, Anthon, Huntsville, Ivan, Judson, Kahola, Kennebec, Kenridge, Lindstrom, Rossville, Sturkie, and Worthen series.
Allison--have a clay content that averages 27 to 35 percent in the particle-size control section
Anthon--have a rock fragment content of 5 to 30 percent in the lower two thirds of the series control section
Huntsville--are stratified with textures ranging from very fine sandy loam to fine sand in the lower third of the series control section and do not have a cambic horizon
Ivan--are calcareous throughout series control section
Judson--have a clay content that averages 30 to 35 percent in the particle-size control section
Kahola--have carbonates within depths of 38 to 102 centimeters
Kennebec--have a mollic epipedon more than 102 centimeters thick, have a clay content of 18 to 30 percent in the particle-size control section, and have a matrix chroma of 1 or 2 throughout the series control section
Kenridge--have redoximorphic features between depths of 86 to 152 centimeters, have a clay content that averages 30 to 35 percent in the particle-size control section, and have a matrix chroma of 1 or 2 throughout the series control section
Lindstrom--have moist bulk density range of 1.30 to 1.40 g/cc in lower third of the series control section and have a reaction range of moderately acid to neutral in lower third of the series control section
Rossville--are in areas where mean annual precipitation ranges from 860 to 1,020 millimeters
Sturkie--have a sand content of more than 10 percent in the series control section and are in areas where mean annual air temperature ranges from 12 to 14 degrees C
Worthen--have a mollic epipedon 61 to 91 centimeters thick, have a clay content of 15 to 26 percent in the lower half of the series control section, and have matrix chroma of 3 to 6 in the lower third of the series control section

GEOGRAPHIC SETTING:
Parent material--local colluvium and alluvium derived from loess
Landform--foot slopes, upland drainageways, and alluvial fans
Slopes--0 to 20 percent
Elevation--290 to 395 meters (950 to 1,300 feet) above sea level
Mean annual air temperature--8 to 12 degrees C (47 to 54 degrees F)
Mean annual soil temperature--9 to 13 degrees C (49 to 56 degrees F)
Mean annual precipitation--710 to 840 millimeters (28 to 33 inches)
Frost-free period--145 to 175 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hamburg, Ida, Kennebec, and Monona soils.
Hamburg--are on the moderately steep to very steep convex shoulders or backslopes on uplands at the higher elevations, have a clay content of 6 to 12 percent in the particle-size control section and have carbonates within a depth of 15 centimeters
Ida--are on uplands at the higher elevations, have a clay content of 18 to 25 percent in the particle-size control section, and have carbonates within a depth of 25 centimeters
Kennebec--are at the lower elevations on flood plains and have a frequently saturated zone within a depth of 0.9 meter in normal years
Monona--are on uplands at the higher elevations, have carbonates within depths of 61 to 183 centimeters, have a mollic epipedon 25 to 51 centimeters thick, and have a clay content of 20 to 30 percent in the particle-size control section

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--a frequently saturated zone does not occur within a depth of 1.8 meters (6 feet) during April to June in normal years
Saturated hydraulic conductivity--1.00 to 10.00 micrometers per second (moderately high)
Surface runoff potential--negligible to medium

USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn, soybeans, small grains, and hay. The native vegetation is big bluestem, little bluestem, indiangrass, switchgrass, and other grasses of the tall grass prairie.

DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic section--Dissected till plains
MLRA--Iowa and Missouri Deep Loess Hills (107)
LRR M; western Iowa, eastern Nebraska, and Missouri, along the tributaries of the Missouri River and the bluffs adjoining the Missouri River valley
Extent-large

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana

SERIES ESTABLISHED: Holt County, Missouri, 1947

REMARKS:
Particle-size control section--the zone from a depth of 25 to 100 centimeters (A, BA, and Bw horizons);
series control section--the zone from the surface to a depth of 150 centimeters (A, BA, Bw, and C horizons).

Diagnostic horizons and features recognized in this pedon:
mollic epipedon--the zone from the surface to a depth of 84 centimeters (Ap, A, and BA horizons);
cambic horizon--the zone from a depth of 94 to 122 centimeters (Bw horizon);
udic moisture regime.

Cation-exchange class is supported by lab sample numbers S1958IA085006, S1995IA047003, and S1996IA193027, KSSL.

Taxonomy version--Keys to Soil Taxonomy, twelfth edition, 2014.

The Napier and Worthen series are currently separated on a geographic basis. Differences in morphology, if any, are not known. The Lindstrom, Huntsville, and Worthen series need further study to aid in differentiation.

ADDITIONAL DATA:
Laboratory data--Kellogg Soil Survey Laboratory, Lincoln, Nebraska, pedon numbers S1958IA085006, S1995IA047003, and S1996IA193027.

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National Cooperative Soil Survey
U.S.A.