LOCATION MCCREATH IA+MNEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Aquic Hapludolls
TYPICAL PEDON: McCreath silty clay loam, in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 6 inches; black (10YR 2/1) silty clay loam, very dark gray (10YR 3/1) dry; weak fine granular and weak fine subangular blocky structure; friable; moderately acid; clear smooth boundary.
A1--6 to 11 inches; black (10YR 2/1) silty clay loam, very dark gray (10YR 3/1) dry; moderate fine granular structure; friable; moderately acid; gradual smooth boundary.
A2--11 to 17 inches; very dark brown (10YR 2/2) silty clay loam, dark grayish brown (10YR 4/2) dry, some mixing of very dark grayish brown (10YR 3/2) and very dark grayish brown (2.5Y 3/2) peds near bottom of horizon; moderate fine subangular blocky structure; friable; few fine dark concretions (oxides); moderately acid; gradual wavy boundary. (Combined thickness of the A horizon is 16 to 20 inches.)
Bw1--17 to 25 inches; dark grayish brown (10YR 4/2) silty clay loam; moderate fine subangular blocky structure; friable; many narrow, very dark gray streaks, apparently old worm casts and root channels; many fine dark concretions (oxides); many fine and few medium tubular pores; slightly acid; gradual smooth boundary.
Bw2--25 to 35 inches; olive brown (2.5Y 4/3) silty clay loam; weak medium prismatic structure parting to weak fine subangular blocky; friable; many very fine faint brown (10YR 5/3) Fe concentrations; many soft dark accumulations (oxides); many fine and very fine tubular pores; slightly alkaline; gradual smooth boundary. (Combined thickness of the Bw horizon is 12 to 20 inches.)
Bk--35 to 44 inches; light olive brown (2.5Y 5/4) silt loam; weak coarse prismatic structure parting to weak subangular blocky; friable; common fine faint grayish brown (2.5Y 5/2) Fe depletions and common very fine distinct brown (10YR 5/3) Fe concentrations; common calcium carbonate concretions up to 1 cm in diameter; many soft dark accumulations (oxides); many fine and few medium tubular pores; strongly effervescent; moderately alkaline; clear wavy boundary. (0 to 10 inches thick)
2BC--44 to 49 inches; light olive brown (2.5Y 5/4) gravelly loam; moderate medium prismatic structure; friable; common fine faint grayish brown (2.5Y 5/2) Fe depletions; common fine and medium tubular pores; pebble band with material 3/4 to 3 inches in diameter, most pebbles have carbonate coats about 1 mm thick on lower surfaces; strongly effervescent; moderately alkaline; clear smooth boundary. (0 to 6 inches thick)
2C--49 to 60 inches; yellowish brown (10YR 5/4) clay loam; massive; firm; common fine distinct grayish brown (2.5Y 5/2) Fe depletions; few lime concretions; some pebbles and stones; strongly effervescent; moderately alkaline.
TYPE LOCATION: O'Brien County, Iowa; about 3 miles west of Hartley; located about 480 feet north and 1,770 feet west of the southeast corner of section 34, T. 97 N., R. 40 W.; USGS Plessis topographic quadrangle; lat. 43 degrees 10 minutes 20 seconds N. and long. 95 degrees 33 minutes 06 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Mollic epipedon thickness--16 to 20 inches
Depth to glacial till--40 to 60 inches
Depth to carbonates--24 to 50 inches
Clay content of the particle-size control section (weighted average)--28 to 35 percent
Sand content of the particle-size control section (weighted average)--less than 3 percent fine sand and sand coarser than fine sand
Additional feature--A coarse textured lag line may occur at the contact of the loess and till
Ap or A horizon:
Hue--10YR or is neutral
Value--2 or 3
Chroma--0 to 2
Texture--silty clay loam
Reaction--moderately acid to neutral
Bg horizon:
Hue--10YR or 2.5Y
Value--4 or 5
Chroma--2 or 3
Texture--silty clay loam
Reaction--slightly acid to slightly alkaline
Bk or C horizon (when present):
Hue--10YR or 2.5Y
Value--4 or 5
Chroma--2 to 4
Texture--silty clay loam or silt loam
Reaction--slightly alkaline or moderately alkaline
Additional feature--common to many secondary carbonate accumulations in the Bk horizon
2BC horizon (when present):
carbonate coats and/or redoximorphic features occur along prismatic structural faces
2C horizon:
Hue--10YR or 2.5Y
Value--4 or 5
Chroma--2 to 4
Texture--loam or clay loam
Clay content--24 to 32 percent
Sand content--30 to 45 percent
Reaction--slightly alkaline or moderately alkaline
Moist bulk density--1.6 to 1.8 g/cc
COMPETING SERIES: These are the
Amana,
Breeds,
Grantcenter,
Joyce,
Kingston,
Klinger,
Klingmore,
Larpenteur,
Nerwoods,
Okabena,
Primghar, and
Ransom series.
Amana--do not have a loamy glacial till materials in the series control section
Breeds--have a paralithic contact in the lower third of the series control section
Grantcenter--do not have a loamy glacial till materials in the series control section
Joyce--have coarse textured material in the lower third of the series control section
Kingston--do not have a loamy glacial till materials in the series control section
Klinger--have loamy glacial till at depths of 20 to 40 inches
Klingmore: have a bulk density of 1.8 to 2.0 g/cc in the lower third of the series control section
Larpenteur--do not have a loamy glacial till materials in the series control section
Nerwoods--have more than 10 percent sand in the upper loamy mantle
Okabena--have a bulk density of 1.4 to 1.6 g/cc in the lower third of the series control section
Primghar--do not have loamy glacial till materials in the series control section
Ransom--have loamy materials at depths of 24 to 40 inches
GEOGRAPHIC SETTING:
Parent material--40 to 60 inches of loess overlying glacial till
Landform--broad, nearly level to convex upland areas with little dissection on till plains and on treads and risers on stream terraces
Slope--0 to 5 percent
Elevation--1,000 to 1,500 feet above sea level
Mean annual air temperature--45 to 50 degrees
Mean annual precipitation--24 to 30 inches
Frost-free period--145 to 170 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Annieville,
Gillett Grove, and
Sac soils.
Annieville--are on higher landscape positions on more convex areas and are moderately well drained
Gillett Grove--are in lower landscape positions in swales and drainageways and are poorly drained
Sac--are on higher landscape positions on more convex areas and are moderately well drained
DRAINAGE AND PERMEABILITY:
Drainage--somewhat poor - seasonal high saturation occurs in the spring of the year at depths as shallow as 1 foot in normal years
Permeability--moderate in the loess and moderate or moderately slow in the glacial till
Surface runoff potential--negligible to low
USE AND VEGETATION: Most areas are cultivated. The principal crops are corn and soybeans with some small grain and hay. The native vegetation is tall prairie grasses.
DISTRIBUTION AND EXTENT: MLRA - Iowa and Minnesota Loess Hills (107A); LRR M; northwestern Iowa and southwestern Minnesota. McCreath soils are of moderate extent.
MLRA OFFICE RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Clay County, Iowa, 2002.
REMARKS:
Diagnostic horizons and features recognized in this pedon include:
Mollic epipedon - zone from the surface to a depth of approximately 17 inches (Ap, A1, and A2 horizons);
Cambic horizon - zone from approximately 17 to 35 inches (Bw1, Bw2);
Calcic horizon - zone from 35 to 44 inches (Bk horizon);
Aquic moisture regime.
This soil was previously included in the Primghar series. Based on MLRA correlation, soils that have 40 to 60 inches of loess over glacial till will be correlated to this series. Soils that have more than 60 inches of loess will be correlated to the Primghar series.