LOCATION ARTHUR                  IA

Established Series
Rev. WND-DBO-TWN
10/2012

ARTHUR SERIES

The Arthur series consists of very deep, well drained soils that formed in 50 to 100 centimeters of loess and underlying stratified sandy eolian material. Arthur soils are on interfluves and side slopes on dissected till plains. Slope ranges from 2 to 14 percent. Mean annual air temperature is about 9 degrees C. Mean annual precipitation is about 710 millimeters.

TAXONOMIC CLASS: Fine-silty over sandy or sandy-skeletal, mixed, superactive, mesic Typic Hapludolls

TYPICAL PEDON: Arthur silty clay loam, on a convex slope of about 3 percent, in a cultivated field. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 15 centimeters; very dark brown (10YR 2/2) silty clay loam, dark grayish brown (10YR 4/2) dry; weak fine and very fine granular structure; friable; few very fine roots; slightly acid; abrupt smooth boundary. (17 to 36 centimeters thick)

BA--15 to 28 centimeters; very dark grayish brown (10YR 3/2) and dark brown (10YR 3/3) silty clay loam, grayish brown (10YR 5/2) and brown (10YR 5/3) dry; weak fine and very fine subangular blocky structure; friable; few very fine roots; common very dark brown (10YR 2/2) worm casts and surfaces lining pores, and few brown (10YR 4/3) worm casts; neutral; clear smooth boundary. (0 to 16 centimeters thick)

Bw1--28 to 43 centimeters; brown (10YR 4/3) silty clay loam; common dark brown (10YR 3/3) coats on faces of peds; weak fine and very fine subangular blocky structure; friable; few very fine roots; common very dark brown (10YR 2/2) and very dark grayish brown (10YR 3/2) worms casts and surfaces lining pores; neutral; clear smooth boundary.

Bw2--43 to 61 centimeters; brown (10YR 4/3) silty clay loam; weak medium and fine subangular blocky structure; friable; few very fine roots; dark brown (10YR 3/3) on few faces of peds; neutral; clear wavy boundary.

Bw3--61 to 81 centimeters; yellowish brown (10YR 5/4) silty clay loam; weak medium subangular blocky structure; friable; few very fine roots; common brown (10YR 4/3) coats on faces of peds; neutral; clear wavy boundary. (Combined thickness of the Bw horizon is 33 to 66 centimeters.)

2BC--81 to 102 centimeters; yellowish brown (10YR 5/4) stratified loamy sand, sand and sandy loam; weak medium subangular blocky structure; very friable; very few, very fine roots; neutral; clear wavy boundary (10 to 30 centimeters thick)

2C1--102 to 183 centimeters; light yellowish brown (10YR 6/4) stratified sand and loamy sand; single grain; loose; very few very fine roots to a depth of 152 centimeters; few 1 to 5 centimeter thick layers of brown (10YR 4/3) and brown (10YR 5/3) loam and silt loam; neutral, clear wavy boundary.

2C2--183 to 198 centimeters; light yellowish brown (10YR 6/4) stratified sand and loamy sand; single grain; loose; slightly alkaline.

TYPE LOCATION: Major Land Resource Area (MLRA) 107-Iowa and Missouri Deep Loess Hills, Ida County, Iowa subset; about 1.5 miles south and 0.5 east of Arthur; located about 2,400 feet west and 150 feet north of the southeast corner of section 25, T. 87 N., R. 39 W.; USGS Odebolt West topographic quadrangle; lat. 42 degrees 18 minutes 45 seconds N. and long. 95 degrees 19 minutes 51 seconds W., NAD 83.

RANGE IN CHARACTERISTICS:
Mollic epipedon thickness--17 to 49 centimeters
Depth to stratified sandy eolian material--50 to 100 centimeters
Clay content in the upper two thirds of the particle-size control section (weighted average)--24 to 32 percent
Clay content in the lower third of the particle-size control section (weighted average)--2 to 10 percent
Sand content of the upper two thirds of the particle-size control section (weighted average)--5 to 15 percent
Sand content of the lower third of the particle-size control section (weighted average)--80 to 95 percent
Rock fragment content--0 percent

Ap or A horizon:
Hue--10YR
Value--2 or 3
Chroma--1 to 3
Texture--silty clay loam
Clay content--27 to 34 percent
Sand content--5 to 15 percent
Reaction--moderately acid to neutral

Most pedons have an AB or BA horizon

Bw horizon:
Hue--10YR
Value--4 or 5
Chroma--3 or 4
Texture--silty clay loam or silt loam
Clay content--24 to 32 percent
Sand content--5 to 15 percent
Reaction--slightly acid or neutral

2BC horizon:
Hue--10YR
Value--4 to 6
Chroma--3 to 6
Texture--stratified loamy sand, sand, and sandy loam
Clay content--less than 10 percent
Sand content--more than 80 percent
Reaction--neutral or slightly alkaline

Some pedons have a 2BC horizon, more than 13 centimeters thick, with a texture of loamy sand or sand

2C horizon:
Hue--10YR
Value--4 to 6
Chroma--3 to 6
Texture--stratified sand and loamy sand--thin layers of material with textures ranging from sandy loam to silt loam are common
Clay content--less than 5 percent
Sand content--more than 80 percent
Reaction--neutral or slightly alkaline

COMPETING SERIES: These are the Allendorf, Baytown and Waukegan series.
Allendorf--have a rock fragment content of 10 to 60 percent in the lower third of the series control section
Baytown--have a paralithic contact of sandstone within a depth of 100 centimeters
Waukegan--have a clay content that averages 18 to 24 percent in the upper half of the particle-size control section

GEOGRAPHIC SETTING:
Parent material--50 to 100 centimeters of loess underlain by stratified sandy eolian material
Landform--interfluves and side slopes on dissected till plains
Slope--2 to 14 percent
Elevation--427 to 442 meters above sea level
Mean annual air temperature--7 to 10 degrees C
Mean annual precipitation--660 to 790 millimeters
Frost-free period--155 to 175 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dickman, Galva, Marshall and Monona soils.
Dickman--are in landscape positions similar to the Arthur soils and have a sand content that averages more than 60 percent in the upper half of the particle-size control section
Galva, Marshall, and Monona--are in landscape positions similar to the Arthur soils and formed entirely in loess and have a sand content of less than 10 percent throughout the series control section

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained--a frequently saturated zone does not occur within a depth of 1.8 meters during April to June in normal years
Saturated hydraulic conductivity--1.00 to 10.00 micrometers per second (moderately high) in the upper mantle and 10.00 to 100.00 micrometers per second (high) in the underlying sandy material
Surface runoff potential--low or medium

USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn, soybeans, small grains, and legume 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; northwestern Iowa
Extent--small

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

SERIES ESTABLISHED: Ida County, Iowa, 1989.

REMARKS:
Particle-size control section--the zone from a depth of 25 to 100 centimeters;
series control section--the zone from the surface to a depth of 150 centimeters.

Diagnostic horizons and features recognized in this pedon include:
mollic epipedon--the zone from the surface of the soil to a depth of 28 centimeters (Ap and BA horizons);
cambic horizon--the zone from a depth of 28 to 102 centimeters (Bw1, Bw2, Bw3, 2BC horizons);
udic moisture regime.

Cation-exchange class is inferred from lab data for similar soils in the surrounding area.

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

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National Cooperative Soil Survey
U.S.A.