LOCATION BACKBONE IA+IL MNEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Mollic Hapludalfs
TYPICAL PEDON: Backbone sandy loam, on a west-facing, convex slope of 4 percent, in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 inches; very dark gray (10YR 3/1) sandy loam, gray (10YR 5/1) dry; weak fine granular structure; very friable; neutral; abrupt smooth boundary. (6 to 9 inches thick)
BE--8 to 17 inches; brown (10YR 4/3) and dark grayish brown (10YR 4/2) sandy loam; few streaks of very dark gray (10YR 3/1) from the Ap horizon; weak fine subangular blocky structure; very friable; neutral; clear smooth boundary. (6 to 10 inches thick)
Bt1--17 to 24 inches; brown (10YR 4/3) and dark yellowish brown (10YR 4/4) sandy loam; weak fine prismatic structure parting to weak fine and very fine subangular blocky; very friable; few distinct dark brown (10YR 3/3) clay films on faces of peds; neutral; clear wavy boundary. (6 to 15 inches thick)
2Bt2--24 to 30 inches; brown (10YR 4/3) and dark yellowish brown (10YR 3/4) clay loam; moderate fine subangular blocky structure; very firm; common distinct dark brown (7.5YR 3/2) clay films on faces of peds; about 5 percent small chert fragments; neutral; abrupt wavy boundary. (0 to 10 inches thick)
2R--30 inches; hard fractured limestone bedrock.
TYPE LOCATION: Winneshiek County, Iowa; about 1/2 mile north of Spillville; about 1700 feet west and 1140 feet north of the southeast corner of sec. 18, T. 97 N., R. 9 W.; USGS Fort Atkinson quadrangle; lat. 43 degrees 12 minutes 55.2 seconds N. and long. 91 degrees 56 minutes 56.8 seconds W., NAD 83
RANGE IN CHARACTERISTICS:
Depth to bedrock--20 to 40 inches
Content of clay in the particle-size control section (weighted average)--12 to 18 percent
Content of sand in the particle-size control section (weighted average)--55 to 80 percent
A or Ap horizon:
Hue--10YR
Value--3
Chroma--1 or 2
Texture--sandy loam, fine sandy loam, or loamy sand
Clay content--5 to 18 percent
Reaction--moderately acid to neutral
BE or E horizon:
Hue--10YR
Value--4 or 5
Chroma--2 or 3
Texture--sandy loam, fine sandy loam, or loamy sand
Clay content--5 to 18 percent
Reaction--strongly acid to neutral
Bt horizon:
Hue--10YR
Value--3 to 5
Chroma--3 to 5
Texture--sandy loam
Clay content--12 to 18 percent
Reaction--strongly acid to neutral
2Bt horizon:
Hue--5YR, 7.5YR, or 10YR
Value--3 to 5
Chroma--3 to 6
Texture--clay loam, sandy clay loam, or clay
Clay content--32 to 42 percent
Rock fragment content--0 to 10 percent, mostly chert or limestone fragments
Reaction--moderately acid to neutral
Some pedons have a 2BC horizon that is very channery, very flaggy, extremely channery, or extremely flaggy. It is loam, clay loam, or sandy clay loam in the fine-earth fraction. This horizon is 0 to 10 inches thick.
COMPETING SERIES: These are the Billet,
Brownchurch,
Desker,
Kingsley,
Oronoco,
Pardeeville, and
Ulster series.
Billett--do not have bedrock within 40 inches
Brownchurch--do not have bedrock within 40 inches
Desker--do not have bedrock within 40 inches
Kingsley--do not have bedrock within 40 inches
Oronoco--do not have bedrock within 40 inches
Pardeeville--do not have bedrock within 40 inches
Ulster--do not have bedrock within 40 inches
GEOGRAPHIC SETTING:
Parent material--moderately coarse or coarse textured eolian material and a thin layer of residuum overlying limestone bedrock at a depth of 20 to 40 inches
Landform--convex ridges and back slopes on uplands
Slopes--2 to 18 percent
Elevation--850 to 1600 feet above sea level
Mean annual air temperature--45 to 50 degrees F.
Mean annual precipitation--30 to 34 inches
Frost-free period--150 to 180 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Marlean,
Nordness,
Rockton, and
Winneshiek soils.
Marlean--are in landscape positions similar to those of the Backbone soils and have more than 35 percent rock fragments in the particle-size control section
Nordness--are on shoulder slopes and have limestone bedrock within 20 inches
Rockton--are in landscape positions similar to those of the Backbone soils and have more than 18 percent clay in the particle-size control section
Winneshiek--are in landscape positions similar to those of the Backbone soils and have more than 18 percent clay in the particle-size control section
DRAINAGE AND PERMEABILITY:
Drainage class--well drained
Permeability--moderately rapid in the eolian material and moderately slow in the residuum
Surface runoff potential--low or medium
USE AND VEGETATION:
More gently sloping areas are cultivated. Corn, small grains, and legume hay are the principal crops. Land use of more strongly sloping areas consists of permanent pasture or woodland. Native vegetation is deciduous trees (oak and hickory) and tall prairie grasses.
DISTRIBUTION AND EXTENT:
LRR M, MLRAs 95B, 104, 105, 108; northeastern Iowa, northern Illinois, and southern Minnesota. This series is of small extent.
MLRA OFFICE RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Bremer County, Iowa, 1965
REMARKS:
Diagnostic horizons and features recognized in this pedon:
particle-size control section--the zone from a depth of 17 to 30 inches (Bt1 and 2Bt2 horizons);
series control section--the zone from the surface to a depth of 30 inches (Ap, BE, Bt1, and 2Bt2 horizons);
ochric epipedon--the zone from the surface to a depth of 17 inches (Ap and BE horizons);
argillic horizon--the zone from a depth of 17 to 30 inches (Bt1 and 2Bt2 horizons);
udic moisture regime.
Cation-exchange class is inferred from lab data from similar soils in the surrounding area.
Taxonomy version--Second Edition, 1999.
Typical pedon location was moved due to urban development on former site.