LOCATION BLENCOE IA+MO NE SDEstablished Series
TAXONOMIC CLASS: Clayey over loamy, smectitic over mixed, superactive, mesic Aquertic Hapludolls
TYPICAL PEDON: Blencoe silty clay, on a slope of about 1/2 percent, on a flood plain in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 15 centimeters; black (10YR 2/1) silty clay, very dark gray (10YR 3/1) dry; moderate fine subangular blocky structure; firm; many roots; few fine pores; neutral; clear smooth boundary.
A--15 to 30 centimeters; black (10YR 2/1) silty clay, dark gray (10YR 4/1) dry; moderate fine subangular blocky structure; firm; many roots; few fine pores; neutral; clear smooth boundary. (Combined thickness of the A horizons is 25 to 43 centimeters.)
BA--30 to 46 centimeters; very dark grayish brown (2.5Y 3/2) silty clay, grayish brown (2.5Y 5/2) dry; faces of peds very dark gray (10YR 3/1), moderate fine subangular blocky structure; firm; black (10YR 2/1) organic stains on faces of peds; few fine roots; very few fine pores; neutral; clear smooth boundary.(0 to 18 centimeters thick)
Bg--46 to 71 centimeters; dark grayish brown (2.5Y 4/2) silty clay; weak medium prismatic structure parting to weak fine subangular blocky; firm; few faces of peds have black (10YR 2/1) organic stains; many root channels; few black iron and manganese oxides; neutral; clear smooth boundary. (20 to 71 centimeters thick)
BCg--71 to 81 centimeters; dark grayish brown (2.5Y 4/2) silty clay loam; weak medium prismatic structure; friable; common root channels; few fine pores; few black iron and manganese oxides; few fine prominent strong brown (7.5YR 5/6) redoximorphic concentrations; neutral; clear smooth boundary. (0 to 13 centimeters thick)
2Cg--81 to 152 centimeters; grayish brown (2.5Y 5/2) silt loam; massive; friable; numerous roots and pores; few worm holes and worm casts; distinct calcium carbonate threads; distinct calcium carbonate concretions; few fine prominent strong brown (7.5YR 5/6) redoximorphic concentrations; strongly effervescent; moderately alkaline.
TYPE LOCATION: Fremont County, Iowa; about 5 miles north and 3 miles west of Hamburg; about 1,220 feet east and 1,840 feet south of the northwest corner of sec. 31, T. 68 N., R. 42 W. 40 degrees, 40 minutes, 7 seconds north latitute; 95 degrees, 42 minutes, 42 seconds west longitude; NAD 83.
RANGE IN CHARACTERISTICS:
Depth to carbonates--38 to 102 centimeters
Depth to cambic horizon--30 to 61 centimeters
Depth to redox concentrations--30 to 102 centimeters
Thickness of mollic epipedon--30 to 61 centimeters
Depth to loamy alluvium--51 to 102 centimeters
Content of clay in the particle-size control section (weighted average)--40 to 52 percent in the clayey alluvium and 5 to 24 percent in the loamy alluvium
Content of sand in the particle-size control section (weighted average)--1 to 15 percent fine sand and sand coarser than fine sand in the clayey alluvium and 15 to 70 percent fine sand and sand coarser than fine sand in the loamy alluvium
A or Ap horizon:
Hue--10YR or neutral
Value--2 or 3
Chroma--0 to 2
Texture--silty clay or silty clay loam
Clay content--30 to 55 percent
Sand content--1 to 20 percent
Reaction--slightly acid to slightly alkaline
AB or BA horizon:
Hue--10YR or 2.5Y
Value--2 or 3
Chroma--1 or 2
Texture--silty clay or silty clay loam
Clay content--38 to 55 percent
Sand content--1 to 20 percent
Reaction--slightly acid or neutral
Bg horizon:
Hue--10YR or 2.5Y
Value--4 or 5
Texture--silty clay loam or silty clay
Clay content--35 to 50 percent
Sand content--1 to 10 percent
Calcium carbonate equivalent--0 to 32 percent
Reaction--neutral or slightly alkaline
BC or BCg horizon (if it occurs):
Hue--10YR or 2.5Y
Value--4 or 5
Chroma--2 to 4
Texture--silty clay loam or silty clay
Clay content--35 to 50 percent
Sand content--1 to 20 percent
Calcium carbonate equivalent: 0 to 20 percent
Reaction: neutral or slightly alkaline
2Cg or 2C horizon:
Hue--10YR or 2.5Y
Value--4 to 6
Chroma--1 to 3
Texture--silt loam, very fine sandy loam, or loamy very fine sand
Clay content--5 to 24 percent
Sand content--15 to 70 percent
Calcium carbonate equivalent--5 to 30 percent
Reaction--slightly alkaline to strongly alkaline
Some pedons have fine sand or loamy fine sand 3C horizons at depths below 152 centimeters.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Parent material--51 to 102 centimeters of clayey alluvium and underlying loamy alluvium
Landform--flood plains and flood-plain steps
Slopes--0 to 2 percent
Elevation--152 to 366 meters above sea level
Mean annual air temperature--8 to 13 degrees C.
Mean annual precipitation--635 to 991 millimeters
Frost-free period--145 to 180 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Cooper,
Keg,
Luton,
Salix, and
Woodbury soils.
Cooper--are at slightly higher elevations and have less than 35 percent clay in the silty alluvium part (upper part) of its particle-size control section.
Keg--are at the higher elevations, do not have saturated zones within a depth of 183 centimeters, and have less than 35 percent clay in the particle-size control section.
Luton--are in lower landscape positions and have saturated zones within a depth of 30 centimeters
Salix--are at slightly higher elevations and have saturated zones within a depth of 90 to 183 centimeters.
Woodbury--are in lower landscape positions, have saturated zones within a depth of 30 centimeters, and have 28 to 36 percent clay in the lower part of the particle-size control section.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--somewhat poorly drained--a saturated zone occurs within a depth of 30 to 90 centimeters during April to June in most years and is considered apparent
Saturated hydraulic conductivity0.42 to 4.23 micrometers per second (moderately low or moderately high) in the clayey alluvium and 4.23 to 14.11 micrometers per second (moderately high or high) in the loamy alluvium
Surface runoff potential--low
Flooding--occasional or rare flooding for very brief to long periods during the months of February to November resulting from precipitation events and snowmelt
USE AND VEGETATION:
Most areas are cultivated. Principal crops are corn, soybeans, and small grain. Some areas have been drained by open ditches and land grading. The native vegetation is big bluestem, indiangrass, switchgrass, and other grasses of the tall grass prairie.
DISTRIBUTION AND EXTENT:
LRR M, MLRAs 102B, 102C, 107B and 115B; flood plains of the Missouri River in Iowa, Missouri, Nebraska and South Dakota. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Monona County, Iowa, 1951.
REMARKS:
Diagnostic horizons and features recognized in this pedon:
Particle-size control section--the zone from a depth of 25 to 100 centimeters (A, BA, Bg, BCg, and 2Cg horizons);
Series control section--the zone from the surface to a depth of 150 centimeters (Ap, A, BA, Bg, BCg, and 2Cg horizons);
Mollic epipedon--the zone from the surface to a depth of 46 centimeters (Ap, A, and BA horizons);
Cambic horizon--the zone from a depth of 46 to 81 centimeters (Bg, and BCg horizons);
Udic soil moisture regime.
Taxonomy version: Second Edition, 1999.