LOCATION BOLAN IAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Typic Hapludolls
TYPICAL PEDON: Bolan loam, on a convex slope of 2 percent, in a grazed pasture. (Colors are for moist soil unless otherwise noted.)
Ap--0 to 23 centimeters; black (10YR 2/1) exterior and very dark brown (10YR 2/2) interior loam, very dark grayish brown (10YR 3/2) dry; moderate fine granular structure; friable; neutral; clear smooth boundary.
A--23 to 36 centimeters; very dark brown (10YR 2/2) exterior and very dark grayish brown (10YR 3/2) interior loam, dark grayish brown (10YR 4/2) dry; weak fine and very fine granular structure; friable; neutral; gradual wavy boundary.
BA--36 to 48 centimeters; dark yellowish brown (10YR 3/4) loam; weak fine subangular blocky structure; friable; dark brown (10YR 3/3) organic stains on faces of peds; neutral; gradual wavy boundary.
Bw--48 to 77 centimeters; dark yellowish brown (10YR 4/4) loam; weak medium subangular blocky structure; friable; dark yellowish brown (10YR 3/4) organic stains on faces of peds; moderately acid; gradual wavy boundary.
BC--77 to 115 centimeters; dark yellowish brown (10YR 4/4) fine sandy loam; weak medium subangular blocky structure; very friable; moderately acid; gradual wavy boundary.
C1--115 to 155 centimeters; dark yellowish brown (10YR 4/4) loamy fine sand; single grain; loose; moderately acid; gradual wavy boundary.
C2--155 to 200 centimeters; brown (10YR 4/3) and brown (10YR 5/3) fine sand; single grain; loose; few fine prominent strong brown (7.5YR 4/6) iron-manganese masses at top of horizon; slightly acid.
TYPE LOCATION: Major Land Resource Area (MLRA) 104-Eastern Iowa and Minnesota Till Prairies, Worth County, Iowa subset; located about 1,130 feet east and 510 feet north of the southwest corner of section 7, T. 98 N., R. 19 W.; USGS Manly topographic quadrangle; lat. 43 degrees 18 minutes 52 seconds N. and long 93 degrees 08 minutes 14 seconds W.; NAD 83.
RANGE IN CHARACTERISTICS:
Thickness of the mollic epipedon--25 to 49 centimeters
Depth to carbonates--more than 120 centimeters
Clay content of the particle-size control section (weighted average)--14 to 18 percent
Sand content of the particle-size control section (weighted average)--40 to 60 percent
Ap or A horizon:
Hue--10YR
Value--2 or 3
Chroma--1 or 2
Texture--loam, silt loam, or sandy loam
Clay content--12 to 27 percent
Sand content--25 to 75 percent
Rock fragment content--0 percent
Reaction--pH 5.6 to 7.3
Thickness--25 to 49 centimeters
AB horizon (when present)
Hue--10YR
Value--3
Chroma--2
Texture--loam, silt loam, or sandy loam
Clay content--12 to 27 percent
Sand content--25 to 75 percent
Rock fragment content--0 percent
Reaction--pH 5.6 to 7.3
Thickness--0 to 12 centimeters
BA horizon (when present):
Hue--10YR
Value--3 or 4
Chroma--3 or 4
Texture--loam or sandy loam
Clay content--12 to 25 percent
Sand content--40 to 70 percent
Rock fragment content--0 percent
Reaction--pH 5.6 to 7.3
Thickness--0 to 23 centimeters
Bw horizon:
Hue--10YR
Value--3 to 6
Chroma--3 to 6
Texture--loam, fine sandy loam or loamy sand
Clay content--7 to 20 percent
Sand content--40 to 85 percent
Rock fragment content--0 percent
Reaction--pH 5.6 to 7.3
Thickness--15 to 36 centimeters
BC horizon:
Hue--10YR
Value--4 or 5
Chroma--4 to 6
Texture--fine sandy loam, loamy fine sand, or loamy sand
Clay content--7 to 15 percent
Sand content--60 to 90 percent
Rock fragment content--0 percent
Reaction--pH 5.6 to 7.3
Thickness--15 to 40 centimeters
C horizon:
Hue--10YR
Value--4 to 6
Chroma--3 to 6
Texture--loamy fine sand, sandy loam, or sand
Clay content--2 to 10 percent
Sand content--75 to 95 percent
Rock fragment content--0 percent
Reaction--pH 5.6 to 7.3
Some pedons have narrow bands of iron and clay accumulation and thin lenses of silt loam below a depth of 125 centimeters
Some pedons have loamy till below a depth of 150 centimeters
COMPETING SERIES: These are the
Augusta Lake,
Aureola,
Bertram,
Dickinson,
Elrick,
Etter,
Filley,
Gardencity,
Olin,
Ridgeport,
Roine,
Wadenill, and
Zenor series.
Augusta Lake--have a sand content of less than 50 percent in the lower third of the particle-size control section
Aureola--have carbonates within a depth of 100 centimeters
Bertram--have a lithic contact with limestone bedrock within a depth of 100 centimeters
Dickinson--have a sand content that averages 60 to 80 percent in the particle-size control section
Elrick--have a sand content that averages 65 to 80 percent in the particle-size control section
Etter--have sandy residuum from sandstone within a depth of 100 centimeters and have a rock fragment content of 2 to 35 percent in the lower third of the series control section
Filley--have a clay content that averages 5 to 18 percent and have a sand content that averages 52 to 85 percent in the particle-size control section
Gardencity--have a sand content that averages 15 to 50 percent in the particle-size control section and have a clay content of 9 to 15 percent in the lower third of the series control section
Olin--have a clay content of 18 to 27 percent in the lower half of the series control section
Ridgeport--have carbonates within a depth of 120 centimeters
Roine--have a clay content of 25 to 33 percent in the lower third of the series control section
Wadenill--have a rock fragment content of 5 to 15 percent in the series control section
Zenor--have carbonates within a depth of 100 centimeters
GEOGRAPHIC SETTING:
Parent material--loamy eolian material or alluvial sediments
Landform--convex slopes on till plains, moraines, dissected till plains and treads and risers on stream terraces in river valleys
Slope--0 to 14 percent
Elevation--155 to 520 meters above sea level
Mean annual air temperature--6 to 11 degrees C
Mean annual precipitation--585 to 965 millimeters
Frost-free period--155 to 205 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Dickinson,
Lawler,
Saude, and
Waukee soils.
Dickinson--are on landscape positions similar to those of the Bolan soils and have a sand content that averages 60 to 80 percent in the particle-size control section
Lawler--are on slightly lower landscape positions on stream terraces and have a frequently saturated zone at depths of 0.3 to 1 meter during the wettest parts of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Saude--are on landscape positions similar to those of the Bolan soils and have a rock fragment content of 5 to 50 percent in the lower third of the series control section
Waukee--are on landscape positions similar to those of the Bolan soils and have a rock fragment content of 10 to 50 percent in the lower half of 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 in years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Saturated hydraulic conductivity--1.00 to 10.00 micrometers per second in the upper materials and 10.00 to 100.00 micrometers per second in the underlying materials
USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn, legume hay, small grains, and soybeans. The native vegetation is big bluestem, indiangrass, switchgrass, and other grasses of the tall grass prairie.
DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic sections--Dissected till plains and Western lake section
MLRAs--Central Iowa and Minnesota Till Prairies (103),
Eastern Iowa and Minnesota Till Prairies (104),
Iowa and Minnesota Loess Hills (107A), and
Illinois and Iowa Deep Loess and Drift, West-Central Part (108C)
LRR M; north-central, northwestern, and east-central Iowa
Extent--small
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota; MLRA SSO 10-11 (Waverly, Iowa)
SERIES ESTABLISHED: Worth County, Iowa, 1972.
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 to a depth of 36 centimeters (Ap and A horizons);
cambic horizon--the zone from a depth of 36 to 115 centimeters (BA, Bw, and BC horizons);
udic moisture regime.
This unit was formerly mapped as Waukegan loam, and subsequently as Saude, Wadena, or Waukee soils.
Type location revisited 8/2009. Location moved slightly due to error with previous locale not in correct delineation.
Cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.
Taxonomy version--Keys to Soil Taxonomy, tenth edition, 2006.