LOCATION BURCHAM IAEstablished Series
TAXONOMIC CLASS: Fine-silty over clayey, mixed, superactive, mesic Aquic Hapludolls
TYPICAL PEDON: Burcham silt loam, on a slope of about 1 percent, on a flood plain, in a cultivated field, at an elevation of about 306 meters (1,005 feet) above sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 18 centimeters (0 to 7 inches); black (10YR 2/1) silt loam, very dark gray (10YR 3/1) dry; weak fine subangular blocky structure; friable; neutral; clear smooth boundary.
A--18 to 28 centimeters (7 to 11 inches); black (10YR 2/1) silt loam, dark gray (10YR 4/1) dry; weak fine subangular blocky structure; friable; neutral; clear smooth boundary. [Combined thickness of the A horizon is 25 to 46 centimeters (10 to 18 inches).]
AB--28 to 36 centimeters (11 to 14 inches); very dark gray (10YR 3/1) and dark grayish brown (10YR 4/2) silt loam, grayish brown (10YR 5/2) dry; weak very fine subangular blocky structure; very friable; few very fine pores; slightly alkaline; clear smooth boundary. [0 to 13 centimeters (0 to 5 inches) thick]
Bg1--36 to 43 centimeters (14 to 17 inches); dark grayish brown (2.5Y 4/2) silt loam; weak very fine subangular blocky structure; very friable; common very fine pores; some very dark gray (10YR 3/1) organic fillings; common fine prominent strong brown (7.5YR 5/6) redoximorphic concentrations; slightly alkaline; clear smooth boundary.
Bg2--43 to 66 centimeters (17 to 26 inches); dark grayish brown (2.5Y 4/2) and olive brown (2.5Y 4/4) silt loam; weak very fine subangular blocky structure; very friable; many very fine and few fine pores; some very dark gray (10YR 3/1) worm casts; common fine prominent strong brown (7.5YR 5/6) redoximorphic concentrations; few fine faint gray (10YR 6/1) redoximorphic depletions; slightly effervescent; moderately alkaline; abrupt smooth boundary. [Combined thickness of the Bg horizon is 18 to 36 centimeters (7 to 14 inches).]
2Cg--66 to 152 centimeters (26 to 60 inches); dark grayish brown (2.5Y 4/2) and dark gray (5Y 4/1) silty clay; massive, but parts along angular blocky planes of weakness; very firm; common very fine pores; shiny coats on some faces of peds; few dark oxides; common fine prominent brown (7.5YR 4/4) and few fine prominent dark reddish brown (5YR 3/4) redoximorphic concentrations; few fine faint grayish brown (2.5Y 5/2) redoximorphic depletions; slightly effervescent; slightly alkaline.
TYPE LOCATION: Major Land Resource Area (MLRA) 107B-Iowa and Missouri Deep Loess Hills; Harrison County, Iowa subset; about 5 miles west of Missouri Valley; about 107 meters (350 feet) north and 774 meters (2,540 feet) east of the southwest corner of section 15, T. 78 N., R. 45 W.; USGS Modale quadrangle; lat. 41 degrees 33 minutes 08 seconds N. and long. 96 degrees 0 minutes 19 seconds W, NAD 83.
RANGE IN CHARACTERISTICS:
Thickness of the mollic epipedon--25 to 60 centimeters (10 to 24 inches)
Depth to clayey alluvium--38 to 102 centimeters (15 to 40 inches)
Depth to carbonates--38 to 50 centimeters (15 to 25 inches)
Content of clay in the upper half of the particle-size control section (weighted average)--18 to 25 percent
Content of clay in the lower half of the particle-size control section (weighted average)--40 to 50 percent
Content of sand in the upper half of the particle-size control section (weighted average)--5 to 50 percent
Content of sand in the lower half of the particle-size control section (weighted average)--less than 15 percent fine sand and sand coarser than fine sand
A or Ap horizon:
Hue--10YR
Value--2 or 3
Chroma--1 or 2
Texture--silt loam or very fine sandy loam
Clay content--15 to 27 percent
Sand content--5 to 50 percent
Reaction--neutral or slightly alkaline
AB horizon (if it occurs):
Hue--10YR
Value--3 or 4
Chroma--1 to 3
Texture--silt loam or very fine sandy loam
Clay content--15 to 27 percent
Sand content--5 to 50 percent
Reaction--neutral or slightly alkaline
Bg or Bw horizon:
Hue--10YR or 2.5Y
Value--4 or 5
Chroma--2 to 4
Texture--silt loam or very fine sandy loam
Clay content--18 to 24 percent
Sand content--5 to 50 percent
Reaction--slightly alkaline or moderately alkaline
Some pedons have a thin 2BCg horizon
2Cg or 2Cyg horizon:
Hue--10YR to 5Y
Value--4 to 6
Chroma--1 or 2
Texture--silty clay
Clay content--40 to 50 percent
Sand content--less than 15 percent
Reaction--slightly alkaline or moderately alkaline
Some pedons have horizons that contain gypsum crystals
COMPETING SERIES: This is the
Hornick series.
Hornick--have a clay content that averages more than 40 percent in the upper one quarter of the series control section
GEOGRAPHIC SETTING:
Parent material--38 to 102 centimeters (15 to 40 inches) of silty alluvium and the underlying clayey alluvium
Landform--nearly level to slightly convex meander scars or escarpments on low intermediate flood plains
Slopes--0 to 2 percent
Elevation--274 to 335 meters (900 to 1,100 feet) above sea level
Mean annual air temperature--8 to 11 degrees C (47 to 52 degrees F)
Mean annual precipitation--660 to 813 millimeters (26 to 32 inches)
Frost-free period--145 to 175 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Blencoe,
Blend,
Keg,
Lakeport, and
Salix soils.
Blencoe--are at slightly lower elevations, have a clay content of 40 to 52 percent in the upper two thirds of the particle-size control section and have a clay content of 18 to 24 percent in the lower third of the particle-size control section
Blend--are at slightly lower elevations and have a frequently saturated zone within a depth of 0.3 meters (1 foot) during April to June in normal years
Keg--are at slightly higher elevations and have a clay content of 18 to 26 percent throughout the particle-size control section
Lakeport--are at slightly lower elevations and have a clay content of 35 to 45 percent throughout the particle-size control section
Salix--are at slightly higher elevations and have a clay content of 27 to 35 percent throughout the particle-size control section
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--moderately well and somewhat poorly drained--a frequently saturated zone occurs at a depth of 0.3 meters (1 foot) during April to June in normal years and is considered perched
Saturated hydraulic conductivity--4.23 to 14.11 micrometers per second (moderately high) in the silty alluvium and 0.01 to 1.41 micrometers per second (low or moderately low) in the underlying clayey alluvium
Surface runoff potential--negligible or low
Flooding--rare flooding for brief periods during the months of February to November resulting from precipitation events and snowmelt
USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn, soybeans, small grains, and meadow. Some areas are irrigated. 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 section--Dissected till plains
MLRA--Iowa and Missouri Deep Loess Hills (107)
LRR M; along the Missouri River in Iowa and possibly Missouri, Nebraska, and South Dakota
Extent--small
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Harrison County, Iowa, 1971.
REMARKS:
Particle-size control section--the zone from a depth of 25 to 100 centimeters (10 to 39 inches) (A, AB, Bg1, Bg2, and 2Cg horizons);
series control section--the zone from the surface to a depth of 150 centimeters (59 inches) (Ap, A, AB, Bg1, Bg2, and 2Cg horizons).
Diagnostic horizons and features recognized in this pedon:
mollic epipedon--the zone from the surface to a depth of 36 centimeters (0 to 14 inches) (Ap, A, and AB horizons);
cambic horizon--the zone from 36 to 66 centimeters (14 to 26 inches) (Bg1 and Bg2 horizons);
udic moisture regime.
Cation-exchange class is inferred from lab data for similar soils in the surrounding area.
Taxonomy version--Keys to Soil Taxonomy, ninth edition, 2003.
ADDITIONAL DATA:
Laboratory data--Iowa State University, Ames, Iowa