LOCATION CASTANA IAEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Entic Hapludolls
TYPICAL PEDON: Castana silt loam, on a southwest-facing, slope of 16 percent, in a pasture. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 inches; very dark grayish brown (10YR 3/2) silt loam; brown (10YR 5/3) dry; weak fine granular structure; friable; many very fine roots; few fine rounded carbonate nodules; strongly effervescent; slightly alkaline; abrupt smooth boundary.
A--8 to 18 inches; very dark grayish brown (10YR 3/2), and dark brown (10YR 3/3) silt loam; brown (10YR 5/3) dry; weak fine and very fine granular structure; friable; many very fine roots; few fine rounded carbonate nodules; strongly effervescent; moderately alkaline; clear smooth boundary. (Combined thickness of the A horizon is 10 to 24 inches.)
AC--18 to 30 inches; brown (10YR 4/3) silt loam; weak fine prismatic structure parting to weak fine granular; friable; very dark grayish brown (10YR 3/2) organic coatings on faces of peds; few fine rounded carbonate nodules; strongly effervescent; moderately alkaline; clear smooth boundary. (0 to 20 inches thick)
C1--30 to 40 inches; brown (10YR 4/3) silt loam; massive; friable; dark brown (10YR 3/3) organic coatings on faces of peds; few fine rounded carbonate nodules; strongly effervescent; moderately alkaline; gradual smooth boundary.
C2--40 to 50 inches; brown (10YR 4/3) silt loam; massive, with evidence of parting along planes of weakness; friable; few fine rounded carbonate nodules; strongly effervescent; moderately alkaline; gradual smooth boundary.
C3--50 to 60 inches; brown (10YR 4/3) and brown (10YR 5/3) silt loam; massive, with evidence of parting along planes of weakness; friable; few fine rounded carbonate nodules; strongly effervescent; moderately alkaline.
TYPE LOCATION: Monona County, Iowa; about 2 miles northwest of Castana; about 900 feet north and 2,490 feet east of the southwest corner of sec. 28, T.84 N., R.44 W.; USGS Castana quadrangle; lat. 42 degrees 3 minutes 15 seconds N. and long. 95 degrees 58 minutes 23 seconds W., NAD 83
RANGE IN CHARACTERISTICS:
Depth to carbonates--0 to 10 inches
Maximum calcium carbonate equivalent--6 to 10 percent
Content of clay in the particle-size control section (weighted average)--18 to 24 percent
Content of sand in the particle-size control section (weighted average)--1 to 6 percent
Some pedons have sand content in the particle-size control section (weighted average)--10 to 25 percent dominated by very fine sand
A or Ap horizon:
Hue--10YR
Value--2 or 3
Chroma--2 or 3
Texture--silt loam or loam
Reaction--neutral to moderately alkaline
AC horizon:
Hue--10YR
Value--4 or 5
Chroma--3 or 4
Texture--silt loam
Reaction--slightly or moderately alkaline
C horizon:
Hue--10YR
Value--4 or 5
Chroma--3 or 4
Texture--silt loam
Reaction--slightly or moderately alkaline
COMPETING SERIES:
There are no competing series.
GEOGRAPHIC SETTING:
Parent material--silty local alluvium and colluvium from loess
Landform--foot slopes
Slopes--5 to 30 percent
Elevation--900 to 1,200 feet above sea level
Mean annual air temperature--47 to 53 degrees F.
Mean annual precipitation--26 to 32 inches
Frost-free period--145 to 175 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Hamburg,
Ida, and
Napier soils.
Hamburg--are at higher elevations and do not have a mollic epipedon
Ida--are in landform positions similar to those of the Castana soils or are at higher elevations and do not have a mollic epipedon
Napier--are in the slightly lower landscape positions and do not have carbonates within a depth of 36 inches
DRAINAGE AND PERMEABILITY:
Drainage class--well drained--a saturated zone does not occur within a depth of 6 feet during April to June in most years
Permeability--moderate
Surface runoff potential--high
USE AND VEGETATION:
Most areas are cultivated. Corn, soybeans, small grain, and legume hay are the principal crops. The more steeply sloping areas are in pasture or timber and pasture. The native vegetation is tall prairie grasses.
DISTRIBUTION AND EXTENT:
LRR M, MLRA 107; western Iowa and possibly northwestern Missouri, principally along the Missouri River and its tributaries. This series is of moderate extent.
MLRA OFFICE RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Monona County, Iowa, 1956.
REMARKS:
Diagnostic horizons and feature recognized in this pedon:
particle-size control section--the zone from a depth of 10 to 40 inches (A, AC and C1 horizons);
series control section--the zone from the surface to a depth of 60 inches (Ap, A, AC, C1, C2, and C3 horizons);
mollic epipedon--from the surface to a depth of 18 inches.(Ap and A horizons);
udic moisture regime.
Cation-exchange class is inferred from lab data for similar soils in the surrounding area.
Taxonomy version--Second Edition, 1999.
Most descriptions available appear to have mollic epipedons less than 24 inches thick, although data tends to indicate that organic carbon content of 1 percent extends to depths of 30 inches in many pedons.