LOCATION LARPENTEUR IAEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Aquic Hapludolls
TYPICAL PEDON: Larpenteur silt loam, on a 1 percent slope, in a cultivated field, at an elevation of 1,055 feet above sea level. (Colors are for moist soils unless otherwise stated.)
Ap--0 to 8 inches; black (10YR 2/1) loam, very dark grayish brown (10YR 3/2) dry; weak fine granular structure; friable; few fine roots; slightly effervescent; slightly alkaline; abrupt smooth boundary.
A--8 to 14 inches; very dark grayish brown (2.5Y 3/2) and dark brown (10YR 3/3) loam, dark grayish brown (10YR 4/2) dry; weak fine subangular blocky structure; friable; few fine roots; strongly effervescent; moderately alkaline; gradual smooth boundary. (Combined thickness of the A horizon is 10 to 24 inches.)
Bg--14 to 20 inches; dark grayish brown (2.5Y 4/2) loam; weak medium subangular blocky structure; friable; few fine roots; strongly effervescent; moderately alkaline; gradual smooth boundary.
Bk--20 to 36 inches; olive brown (2.5Y 4/4) loam; weak medium subangular blocky structure; friable; few fine roots; few fine and medium rounded carbonate nodules and few fine rounded carbonate concretions; few prominent strong brown (7.5YR 4/6) and few fine distinct light olive brown (2.5Y 5/6) redoximorphic concentrations; strongly effervescent; moderately alkaline; gradual smooth boundary. (Combined thickness of the B horizon is 16 to 30 inches.)
Cg--36 to 60 inches; grayish brown (2.5Y 5/2) loam; massive; friable; very few distinct very dark grayish brown (10YR 3/2) organic stains on faces of peds; few fine prominent yellowish brown (10YR 5/6) redoximorphic concentrations; strongly effervescent; moderately alkaline.
TYPE LOCATION: Monona County, Iowa; about 900 feet west and 1,500 feet north of the southeast corner of sec. 13, T. 85 N., R. 45 W.; USGS Hornick quadrangle; lat. 42 degrees 10 minutes 21 seconds N. and long. 96 degrees 1 minute 31 seconds W., NAD 27
RANGE IN CHARACTERISTICS:
Depth to carbonates--0 to 10 inches
Thickness of the mollic epipedon--10 to 24 inches
Depth to the base of the cambic horizon--30 to 54 inches
Content of clay in the particle-size control section (weighted average)--20 to 30 percent
Content of sand in the particle-size control section (weighted average)--5 to 15 percent fine sand or sand coarser than fine sand
A or Ap horizon:
Hue--10YR or 2.5Y
Value--2 or 3
Chroma--1 to 3
Texture--silt loam, silty clay loam, or loam
Clay content--20 to 30 percent
Sand content--15 to 35 percent
Reaction--neutral to moderately alkaline
Moist bulk density--1.35 g/cc to 1.45 g/cc
BA horizon (if it occurs):
Hue--10YR or 2.5Y
Value--3 or 4
Chroma--2 or 3
Texture--silt loam, clay loam, or loam
Clay content--20 to 27 percent
Sand content--15 to 40 percent
Reaction--slightly alkaline or moderately alkaline
Moist bulk density--1.35 g/cc to 1.45 g/cc
Bw or Bg horizon:
Hue--10YR or 2.5Y
Value--4 or 5
Chroma--2 to 4
Texture--silt loam or loam
Clay content--20 to 27 percent
Sand content--15 to 40 percent
Reaction--slightly alkaline or moderately alkaline
Moist bulk density--1.35 g/cc to 1.45 g/cc
Bk or Bkg horizon:
Hue--10YR or 2.5Y
Value--4 or 5
Chroma--2 to 4
Texture--silt loam or loam
Clay content--20 to 27 percent
Sand content--15 to 35 percent
Reaction--slightly alkaline to strongly alkaline
Moist bulk density--1.35 g/cc to 1.45 g/cc
C horizon:
Hue--10YR or 2.5Y
Value--4 or 5
Chroma--2 to 4
Texture--silt loam or loam
Clay content--18 to 27 percent
Sand content--15 to 55 percent
Reaction--slightly alkaline to strongly alkaline
Moist bulk density--1.35 g/cc to 1.45 g/cc
Some pedons have silty clay loam textures below a depth of 40 inches
COMPETING SERIES: These are the
Amana,
Breeds,
Grantcenter,
Joy,
Joyce,
Kingston,
Klinger,
Klingmore,
Lakefield,
McCreath (T),
Minden,
Muscatine,
Nerwoods,
Okabena (T),
Primghar, and
Ransom series.
Amana--do not have carbonates within a depth of 60 inches and have a variable coarse silt to fine silt ratio in the series control section
Breeds--have a shale paralithic contact within a depth of 60 inches
Grantcenter--have a depth to carbonates range of 24 to 60 inches
Joy--do not have carbonates within a depth of 40 inches
Joyce--have more than 70 percent sand in the lower third of the series control section
Kingston--have a depth to carbonates range of 20 to 40 inches
Klinger--have a moist bulk density range of 1.8 g/cc to 2.0 g/cc in the lower two thirds of the series control section
Klingmore--have a moist bulk density range of 1.8 g/cc to 2.0 g/cc in the lower third of the series control section
Lakefield--have a sand content of less than 15 percent fine sand and sand coarser than fine sand in the lower half of the series control section
McCreath(T)--have a moist bulk density range of 1.6 g/cc to 1.8 g/cc in the lower third of the series control section
Minden--do not have carbonates within a depth of 60 inches and have a sand content of less than 10 percent throughout the series control section
Muscatine--do not have carbonates in the upper two thirds of the series control section and have less than 5 percent sand in the particle-size control section
Nerwoods--have carbonates between depths of 40 to 80 inches and have a sand content of more than 15 percent in the upper third of the series control section
Okabena(T)--have carbonates between depths of 20 to 40 inches and have 2 to 8 percent rock fragments in the lower third of the series control section
Primghar--have a sand content of less than 3 percent throughout the particle-size control section
Ransom--have carbonates between depths of 22 to 40 inches and have 2 to 8 percent rock fragments in the lower half of the series control section
GEOGRAPHIC SETTING:
Parent material--medium to moderately fine textured calcareous alluvium
Landform--old stream meanders and natural levees on flood plains
Slopes--0 to 2 percent
Elevation--700 to 1,200 feet above sea level
Mean annual air temperature--47 to 52 degrees F.
Mean annual precipitation--26 to 32 inches
Frost-free period--145 to 175 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Blencoe,
Grantcenter,
Napa,
Tieville, and
Woodbury soils.
Blencoe--are at the lower elevations, have 40 to 52 percent clay in the upper two thirds of the particle-size control section, and have a depth to carbonates range of 25 to 40 inches
Grantcenter--are in landform positions similar to those of the Larpenteur soils and have a depth to carbonates range of 24 to 60 inches
Napa--are in the lower landscape positions and have nests of gypsum and other salts within a depth of 16 inches
Tieville--are at the lower elevations, have a clay content of 40 to 60 percent in the particle-size control section, and have carbonates within 10 inches
Woodbury--are at the lower elevations, have a clay content of 40 to 55 percent in the particle-size control section, and have a depth to carbonate range of 36 to 60 inches
DRAINAGE AND PERMEABILITY:
Drainage class--somewhat poorly drained--a saturated zone occurs within depths of 1 to 3 feet during April to June in most years and is considered apparent
Permeability--moderate
Surface runoff potential--low
Flooding--rare flooding for brief or very 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, soybean and small grains. The native vegetation is big bluestem, indiangrass, switchgrass, and other grasses of the tall grass prairie.
DISTRIBUTION AND EXTENT:
LRR M, MLRA 107; flood plains of the Missouri River in Iowa and possibly in Missouri, Nebraska and South Dakota. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Monona County, Iowa, 1995
REMARKS:
Particle-size control section--the zone from a depth of 10 to 40 inches (A, Bg, Bk, and Cg horizons);
series control section--the zone from the surface to a depth of 60 inches (Ap, A, Bg, Bk, and Cg horizons).
Diagnostic horizon and features recognized in this pedon:
mollic epipedon--the zone from the surface to a depth of 14 inches (Ap and A horizons);
cambic horizon--the zone from a depth of 14 to 36 inches (Bg and Bk horizons);
calcic horizon--the zone from a depth of 20 to 36 inches (Bk horizon);
udic moisture regime.
Cation exchange activity class is supported by lab sample number S92IA-133-001, NSSL.
Taxonomy version--second edition, 1999.
Larpenteur soils were formerly included with the Colo and Zook series or mapped as a calcareous variant of these series in previous surveys. Larpenteur soils were formerly mapped as Colo, moderately deep to silt loam phase.
ADDITIONAL DATA:
Laboratory data--Iowa State University Ames, Iowa, pedon number 98-IA-193-012A;
Laboratory data--National Soil Survey Laboratory, Lincoln, Nebraska, pedon number S92IA-133-001, (http://ssldata.sc.egov.usda.gov/).