LOCATION AINSWORTH IAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Typic Hapludalfs
TYPICAL PEDON: Ainsworth silt loam, on a convex slope of about 2 1/2 percent, in a cultivated field, at elevation of about 197 meters above mean sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 23 centimeters; dark grayish brown (10YR 4/2) and brown (10YR 4/3) silt loam, light brownish gray (10YR 6/2) and pale brown (10YR 6/3) dry; weak fine granular structure; weak platy structure in lower 3 centimeters of horizon; friable; slightly acid; abrupt smooth boundary. (15 to 23 centimeters thick)
Bt1--23 to 46 centimeters; dark yellowish brown (10YR 4/4) and brown (10YR 4/3) silty clay loam; moderate fine subangular blocky structure; firm; few distinct clay films on faces of peds; many light gray (10YR 7/2) dry silt coats on faces of peds; few dark concretions (iron and manganese oxides); neutral; gradual smooth boundary.
Bt2--46 to 76 centimeters; yellowish brown (10YR 5/4) and brown (10YR 4/3) silty clay loam; moderate medium subangular blocky structure; firm; common clay films on faces of peds; many light gray (10YR 7/2) dry silt coats on faces of peds; few dark concretions (iron and manganese oxides); strongly acid; gradual smooth boundary.
Bt3--76 to 94 centimeters; yellowish brown (10YR 5/4) and brown (10YR 4/3) silty clay loam; weak fine prismatic structure parting to weak fine subangular blocky; friable; few clay films on faces of peds; common light gray (10YR 7/2) dry silt coats on faces of peds; few dark concretions (iron and manganese oxides); strongly acid; gradual smooth boundary. (Combined thickness of the Bt horizon is 60 to 100 centimeters.)
2Bt4--94 to 111 centimeters; yellowish brown (10YR 5/4) and brown (10YR 4/3) loam; weak medium prismatic structure; friable; few clay films on faces of peds; few light gray (10YR 7/2) dry silt coats on faces of peds; few dark concretions (iron and manganese oxides); few medium distinct strong brown (7.5YR 5/6) redoximorphic concentrations; few fine distinct light brownish gray (10YR 6/2) redoximorphic depletions; moderately acid; gradual smooth boundary. (0 to 25 centimeters thick)
2BC--111 to 132 centimeters; yellowish brown (10YR 5/4) fine sandy loam; weak medium prismatic structure; friable; moderately acid; clear wavy boundary. (0 to 25 centimeters thick)
2C1--132 to 153 centimeters; yellowish brown (10YR 5/4) fine sandy loam; single grain; loose; moderately acid; gradual wavy boundary.
2C2--153 to 203 centimeters; strong brown (7.5YR 5/6) and yellowish brown (10YR 5/4) sand; single grain; loose; moderately acid.
TYPE LOCATION: Major Land Resource Area (MLRA) 108C-Illinois and Iowa Deep Loess and Drift, West Central Part; Washington County, Iowa subset; about 2 miles south of Crawfordsville; located about 1,570 feet east and 1,100 feet north of the southwest corner of section 27, T. 74 N., R. 6 W.; USGS Crawfordsville topographic quadrangle; lat. 41 degrees 10 minutes 50 seconds N. and long. 91 degrees 32 minutes 15 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Depth to sandy sediments--100 to 150 centimeters
Depth to carbonates--greater than 180 centimeters
Clay content in the particle-size control section (weighted average)--35 to 38 percent
Sand content in the particle-size control section (weighted average)--less than 5 percent
Ap horizon:
Hue--10YR
Value--4 or 5
Chroma--2 or 3
Texture--silt loam or silty clay loam
Clay content--20 to 30 percent
Sand content--less than 5 percent
Rock fragment content--0 percent
Reaction--moderately acid to neutral
A horizon (when present):
Hue--10YR
Value--3 or 4
Chroma--2 or 3
Texture--silt loam or silty clay loam
Clay content--20 to 30 percent
Sand content--less than 5 percent
Rock fragment content--0 percent
Reaction--moderately acid to neutral
Thickness--0 to 13 centimeters
E horizon (when present):
Hue--10YR
Value--4 to 6
Chroma--2 or 3
Texture--silt loam
Clay content--18 to 25 percent
Sand content--less than 5 percent
Rock fragment content--0 percent
Reaction--strongly acid to slightly acid
Some pedons have a BE horizon as much as 20 centimeters thick
Bt horizon:
Hue--7.5YR or 10YR
Value--4 or 5
Chroma--3 or 4
Texture--silty clay loam
Clay content--35 to 40 percent
Sand content--less than 5 percent
Rock fragment content--0 percent
Reaction--very strongly acid to neutral
2Bt horizon (when present):
Hue--7.5YR or 10YR
Value--4 or 5
Chroma--2 to 4
Texture--loam or clay loam
Clay content--20 to 30 percent
Sand content--15 to 35 percent
Rock fragment content--0 percent
Reaction--very strongly acid to moderately acid
2BC horizon (when present):
Hue--7.5YR or 10YR
Value--4 or 5
Chroma--2 to 4
Texture--sandy loam, loam, or fine sandy loam
Clay content--10 to 18 percent
Sand content--45 to 75 percent
Rock fragment content--0 to 5 percent, mixed lithology
Reaction--very strongly acid to moderately acid
2C horizon:
Hue--7.5YR or 10YR
Value--4 or 5
Chroma--3 to 6
Texture--fine sandy loam, sand, or loamy sand
Clay content--5 to 15 percent
Sand content--70 to 95 percent
Rock fragment content--0 to 5 percent, mixed lithology
Reaction--very strongly acid to moderately acid
COMPETING SERIES: These are the
Bonnefemme,
Brevator,
Clinton,
Haymarket,
Lunt,
Mirerock, and
Welda series.
Bonnefemme--have a lithic contact within a depth of 100 centimeters
Brevator--have a clay content of 35 to 50 percent in the lower third of the series control section
Clinton--a sand content of less than 5 percent in the lower third of the series control section
Haymarket--are in areas that have a mean annual precipitation range of 910 to 1,120 millimeters and may contain rock fragments of diabase or basalt
Lunt--are in areas that have a mean annual precipitation range of 960 to 1,120 millimeters and have a rock fragment content, mainly quartz, of 1 to 10 percent in the upper half of the series control section
Mirerock--are in areas that have a mean annual precipitation range of 910 to 1,120 millimeters and have a paralithic contact within a depth of 100 centimeters
Welda--contain less than 20 percent sand in the lower third of the series control section
GEOGRAPHIC SETTING:
Parent material--100 to 150 centimeters of silty alluvium and the underlying sandy sediments
Landform--treads and risers on stream terraces
Slope--0 to 18 percent
Elevation--168 to 213 meters above sea level
Mean annual air temperature--9 to 12 degrees C
Mean annual precipitation--780 to 870 millimeters
Frost-free period--160 to 180 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Coppock,
Koszta,
Lawson, and
Okaw soils.
Coppock--are at lower landscape positions on flood plains and have an average clay content of 27 to 35 percent in the particle-size control section
Koszta--are at slightly lower landscape positions on stream terraces and have an average clay content of 27 to 35 percent in the particle-size control section
Lawson--are at lower landscape positions on flood plains commonly adjacent to the stream channels and have mollic epipedons that are greater than 60 centimeters thick
Okaw--are at higher landscape positions on nearly level areas on stream terraces and have an average clay content of 40 to 60 percent in the particle-size control section
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--moderately well drained--a frequently saturated zone occurs at a depth of 1 meter during April to June in normal years and is considered apparent
Saturated hydraulic conductivity--1.0 to 10.0 micrometers per second (moderately high) in the silty sediments and 10.0 to 100 micrometers (high) in the underlying sandy sediments
Surface runoff potential--negligible to medium
Flooding--rarely flooded for brief or very brief duration
USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn and soybeans. Oats and legume-grass hays are also grown in some areas. A few areas remain in native hardwoods.
DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic section--Dissected till plains
MLRAs--Illinois and Iowa Deep Loess and Drift (108) and Iowa and Missouri Heavy Till Plain (109)
LRR M; southern and southeastern Iowa
Extent--small
MLRA OFFICE RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Henry County, Iowa, 1982.
REMARKS:
Particle-size control section--the zone from a depth of 23 to 73 centimeters;
series control section--the zone from the surface to a depth of 150 centimeters.
Diagnostic horizons and features recognized in this pedon include:
ochric epipedon--the zone from the surface to a depth of 23 centimeters (Ap horizon);
argillic horizon--the zone from a depth of 23 to 111 centimeters (Bt1, Bt2, Bt3, and 2Bt4 horizon);
udic moisture regime.
Taxonomy version--Keys to Soil Taxonomy, tenth edition, 2006.
ADDITIONAL DATA:
Laboratory data--National Soil Survey Laboratory, Lincoln, Nebraska - user pedon ID 03IA183001 (http://ssldata.nrcs.usda.gov/).