LOCATION HUMESTON IA+MO

Established Series
Rev. LDL-JES-RJB
06/2015

HUMESTON SERIES

The Humeston series consists of very deep, poorly drained soils formed in alluvium. These soils are on foot slopes and flood plains. Slope ranges from 0 to 5 percent. Mean annual temperature is about 10 degrees C. Mean annual precipitation is about 850 millimeters (33.5 inches).

TAXONOMIC CLASS: Fine, smectitic, mesic Argiaquic Argialbolls

TYPICAL PEDON: Humeston silty clay loam, on a nearly level bottom land, in a pasture. (Colors are for moist soil unless otherwise noted.)

A--0 to 28 centimeters (0 to 11 inches); black (10YR 2/1) silty clay loam, dark gray (10YR 4/1) dry; moderate medium granular structure; friable; common fine roots throughout; slightly acid; abrupt smooth boundary.

E1--28 to 41 centimeters (11 to 16.1 inches); dark gray (10YR 4/1) silt loam, gray (10YR 6/1) dry; moderate medium platy structure; friable; common fine roots throughout; few distinct gray (10YR 6/1) dry, silt coats on horizontal faces of peds; common distinct very dark gray (10YR 3/1) organic stains on horizontal faces of peds; common fine distinct dark yellowish brown (10YR 4/4) masses of oxidized iron on horizontal faces of peds; moderately acid; clear smooth boundary.

E2--41 to 64 centimeters (16.1 to 25.2 inches); dark gray (10YR 4/1) silt loam, gray (10YR 6/1) dry; strong coarse platy structure; friable; common fine roots throughout; common distinct light gray (10YR 7/1) dry, silt coats on horizontal faces of peds; few distinct very dark gray (10YR 3/1) organic stains on horizontal faces of peds; common fine distinct dark yellowish brown (10YR 4/4) masses of oxidized iron throughout; moderately acid; clear smooth boundary.

BE--64 to 78 centimeters (25.2 to 30.7 inches); dark gray (10YR 4/1) silty clay loam; weak thin platy structure parting to moderate fine subangular blocky; friable; few distinct light gray (10YR 7/2) dry, silt coats on all faces of peds; few distinct very dark gray (10YR 3/1) organic stains on all faces of peds; common fine distinct dark yellowish brown (10YR 4/4) masses of oxidized iron throughout; moderately acid; clear smooth boundary.

Btg1--78 to 102 centimeters (30.7 to 40.2 inches); very dark gray (10YR 3/1) silty clay loam; moderate fine subangular blocky structure; friable; common fine roots throughout; common distinct black (10YR 2/1) organoargillans on all faces of peds; common fine distinct dark yellowish brown (10YR 4/4) masses of oxidized iron throughout; slightly acid; clear smooth boundary.

Btg2--102 to 130 centimeters (40.2 to 51.2 inches); very dark gray (10YR 3/1) silty clay loam; moderate medium subangular blocky structure; firm; few fine roots throughout; common distinct black (10YR 2/1) organoargillans on all faces of peds; common fine prominent brown (7.5YR 4/4) masses of oxidized iron throughout; slightly acid; clear smooth boundary.

Btg3--130 to 158 centimeters (51.2 to 62.2 inches); very dark gray (2.5Y 3/1) silty clay; weak fine prismatic structure parting to moderate fine angular blocky; firm; very few fine roots throughout; few distinct black (10YR 2/1) organoargillans on all faces of peds; common fine faint dark grayish brown (2.5Y 4/2) iron depletions throughout; common fine prominent strong brown (7.5YR 4/6) masses of oxidized iron throughout; slightly acid; clear smooth boundary.

Btg4--158 to 183 centimeters (62.2 to 72 inches); very dark gray (2.5Y 3/1) silty clay loam; moderate medium prismatic structure; firm; very few fine roots throughout; few distinct black (10YR 2/1) organoargillans on vertical faces of peds; common fine faint dark grayish brown (2.5Y 4/2) iron depletions throughout; common fine prominent strong brown (7.5YR 4/6) masses of oxidized iron throughout; slightly acid; clear smooth boundary.

BCg--183 to 200 centimeters (72 to 78.7 centimeters); dark grayish brown (2.5Y 4/2) silty clay loam; weak medium prismatic structure; firm; very few fine roots; very few distinct very dark gray (10YR 3/1) organoargillans on vertical faces of peds; many fine prominent strong brown (7.5YR 4/6) masses of oxidized iron throughout; slightly acid.

TYPE LOCATION: Major Land Resource Area (MLRA) 109-Iowa and Missouri Heavy Till Plain, Wayne County, Iowa subset; about 3 miles south and 4 miles east of Humeston; located about 2,520 feet south and 160 feet west of the northeast corner of section 31, T. 70 N., R. 22 W.; USGS Humeston topographic quadrangle; lat. 40 degrees 49 minutes 9.02 seconds N. and long. 93 degrees 25 minutes 22.88 seconds W., NAD 83.

RANGE IN CHARACTERISTICS:
Thickness of mollic epipedon--25 to 46 centimeters (9.8 to 18.1 inches)
Depth to carbonates--more than 180 centimeters (70.9 inches)
Clay content of the particle-size control section (weighted average)--35 to 42 percent
Sand content of the particle-size control section (weighted average)--less than 10 percent

A or Ap horizon:
Hue--10YR
Value--2 or 3
Chroma--1
Texture--silt loam or silty clay loam
Clay content--20 to 30 percent
Sand content--less than 10 percent
Reaction--strongly acid to neutral
Thickness--25 to 46 centimeters (9.8 to 18.1 inches)

E horizon:
Hue--10YR
Value--3 to 5
Chroma--1
Texture--silt loam
Clay content--15 to 26 percent
Sand content--less than 10 percent
Reaction--very strongly acid to moderately acid
Thickness--15 to 36 centimeters (5.9 to 14.2 inches)

BE horizon:
Hue--10YR
Value--2 to 4
Chroma--1
Texture--silty clay loam or silt loam
Clay content--24 to 35 percent
Sand content--less than 10 percent
Reaction--very strongly acid to moderately acid
Thickness--0 to 20 centimeters (0 to 7.9 inches)

Btg horizon:
Hue--10YR to 5Y, or is neutral
Value--2 or 3
Chroma--0 or 1
Texture--silty clay loam or silty clay
Clay content--35 to 48 percent
Sand content--less than 10 percent
Reaction--very strongly acid to slightly acid
Thickness--40 to 110 centimeters (15.8 to 43.3 inches)

BCg or Cg horizon (when present):
Hue--10YR to 5Y
Value--3 to 5
Chroma--1 or 2
Texture--silty clay loam
Clay content--30 to 38 percent
Sand content--less than 10 percent
Reaction--very strongly acid to slightly acid

COMPETING SERIES:
These are the Arbela, Leslie, and Tetonka series.
Arbela--have a matrix value of 4 or 5 in the argillic horizon and have a sand content of more than 5 percent in all parts of the series control section
Leslie--have a matrix value of 3 to 6 in the argillic horizon and have a sand content that averages less than 5 percent in the series control section
Tetonka--have a reaction range of neutral to moderately alkaline in the lower third of the series control section

GEOGRAPHIC SETTING:
Parent material--alluvium
Landform--concave foot slopes and slightly concave backswamps of floodplains
Slope--0 to 5 percent
Elevation--155 to 460 meters above sea level
Mean annual air temperature--8 to 13 degrees C
Mean annual precipitation--660 to 1,040 millimeters (26 to 40.9 inches)
Frost-free period--155 to 220 days

GEOGRAPHICALLY ASSOCIATED SOILS:
These are the Colo, Kennebec, Vesser, and Wabash soils.
Colo--are at slightly lower landscape positions on floodplains, have a mollic epipedon more than 90 centimeters (35.4 inches) thick and have a clay content that averages 27 to 35 percent in the particle-size control section
Kennebec--are at slightly higher landscape positions on floodplains and have a clay content that averages 18 to 35 percent in the particle-size control section
Vesser--are at slightly higher landscape positions on foot slopes or alluvial fans and have a clay content that averages 30 to 35 percent in the particle-size control section
Wabash--are at slightly lower landscape positions on floodplains, have a mollic epipedon 90 to 115 centimeters (35.4 to 45.3 inches) thick and have a clay content that averages 45 to 60 percent in the particle-size control section

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--poorly drained--a frequently saturated zone typically occurs at the soil surface to a depth of 0.3 meter (11.8 inches) at some time during most years.
Saturated hydraulic conductivity--1.0 to 10.00 micrometers per second in the surface and subsurface horizons and 0.01 to 1.0 micrometers per second in the argillic horizon and substratum
Flooding--rarely or occasionally flooded for brief duration from precipitation events and snowmelt

USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn and soybeans. Some areas are in permanent pasture. The native vegetation is big bluestem, little bluestem, switchgrass, other grasses of the tall grass prairie and scattered deciduous trees. See Additional Data section for native vegetative cover in Iowa.

DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowlands
Physiographic sections--Dissected till plains
MLRAs--Iowa and Missouri Deep Loess Hills (107B); Illinois and Iowa Deep Loess and Drift, West-Central Part (108C); Illinois and Iowa Deep Loess and Drift, Western Part (108D); and Iowa and Missouri Heavy Till Plain (109)
LRR M; southern Iowa and northern Missouri
Extent--moderate

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

SERIES ESTABLISHED:
Lucas County, Iowa, 1940.

REMARKS:
Particle size control section--the zone from a depth of 78 to 128 centimeters (30.7 to 50.4 inches);
series control section--the zone from the surface to a depth of 183 centimeters (72 inches).

Diagnostic horizons and features recognized in this pedon include:
mollic epipedon--the zone from the surface to a depth of 28 centimeters (11 inches) (A horizon);
albic horizon--the zone from a depth of 28 to 64 centimeters (11 to 25.2 inches) (E1 and E2 horizons);
argillic horizon--the zone from a depth of 78 to 183 centimeters (30.7 to 72 inches) (Btg1, Btg2, Btg3, and Btg4 horizons);
aquic moisture regime.

This update relocates the type location to better represent the central concept of the Humeston series.

Taxonomy version--Keys to Soil Taxonomy, eleventh edition, 2010.

ADDITIONAL DATA:
Laboratory data--National Soil Survey Laboratory, Lincoln, Nebraska-user pedon id 71IA185002 (http://ssldata.sc.egov.usda.gov/).

In Iowa, the native vegetative cover is a herbaceous wetland community commonly inhabited with Prairie Cordgrasses, Bluejoint Grasses, Fox Sedges, Oval Sedges, Inland Rushes, New England Asters, Foxglove Penstemons, Cool Mountain Mints, Prairie Sundrops, Winged Loosestrifes, and Saw-Tooth Sunflowers. Source: Iowa State Office, Natural Resources Conservation Service, Des Moines, IA.

National Cooperative Soil Survey
U.S.A.