LOCATION LUTHER IAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Aeric Endoaqualfs
TYPICAL PEDON: Luther loam, on a slope of less than 1 percent, in a forested pasture. (Colors are for moist soil unless otherwise stated.)
A--0 to 10 centimeters; very dark grayish brown (10YR 3/2) loam, gray (10YR 5/1) dry; moderate fine subangular blocky structure parting to moderate fine granular; friable; many very fine roots; many fine tubular pores; common distinct very dark gray (10YR 3/1) coats on faces of peds; about 2 percent rock fragments; slightly acid; clear smooth boundary. (5 to 13 centimeters thick)
E1--10 to 18 centimeters; dark grayish brown (10YR 4/2) loam, light brownish gray (10YR 6/2) dry; moderate fine subangular blocky structure parting to moderate fine granular; friable; many very fine roots; common very fine tubular pores; common distinct very dark gray (10YR 3/1) coats on faces of peds; about 2 percent rock fragments; slightly acid; clear smooth boundary.
E2--18 to 25 centimeters; dark grayish brown (10YR 4/2) loam, light brownish gray (10YR 6/2) dry; weak medium platy structure parting to weak fine subangular blocky; very friable; common very fine roots; many very fine irregular pores; common distinct very dark grayish brown (10YR 3/2) coats on faces of peds; common distinct gray (10YR 5/1) uncoated silt and sand grains on faces of peds; about 2 percent rock fragments; slightly acid; clear smooth boundary.
E3--25 to 38 centimeters; dark grayish brown (10YR 4/2) loam, light brownish gray (10YR 6/2) dry; moderate fine subangular blocky structure; friable; common very fine roots; common very fine irregular and tubular pores; common distinct very dark grayish brown (10YR 3/2) coats on faces of peds; common distinct gray (10YR 5/1) uncoated silt and sand grains on faces of peds; about 2 percent rock fragments; slightly acid; clear smooth boundary. (Combined thickness of the E horizon is 20 to 36 centimeters.)
Bt1--38 to 46 centimeters; dark grayish brown (10YR 4/2) clay loam; moderate medium subangular blocky structure; firm; common very fine roots; common very fine irregular and tubular pores; common distinct very dark grayish brown (10YR 3/2) clay films on faces of peds; about 2 percent rock fragments; moderately acid; clear smooth boundary.
Bt2--46 to 56 centimeters; dark grayish brown (10YR 4/2) clay loam; weak medium prismatic structure parting to moderate medium angular blocky; firm; few very fine roots; few very fine irregular and tubular pores; common distinct very dark grayish brown (10YR 3/2) clay films on faces of peds and along surfaces of pores; about 2 percent rock fragments; moderately acid; clear smooth boundary.
Bt3--56 to 71 centimeters; brown (10YR 5/3) clay loam; weak medium prismatic structure parting to weak medium angular blocky; firm; few very fine roots; few very fine tubular pores; common distinct dark grayish brown (2.5Y 4/2) clay films on faces of peds and along surfaces of pores; few manganese concretions; common fine faint grayish brown (2.5Y 5/2) redoximorphic depletions; few fine prominent strong brown (7.5YR 5/6) redoximorphic concentrations; about 2 percent rock fragments; slightly acid; clear smooth boundary.
Btg--71 to 91 centimeters; grayish brown (2.5Y 5/2) clay loam; weak medium prismatic structure parting to weak medium angular blocky; firm; few very fine roots; few very fine tubular pores; common distinct dark grayish brown (2.5Y 4/2) clay films on faces of peds and along surfaces of pores; common distinct dark grayish brown (2.5Y 4/2) coatings on faces of peds; many manganese concretions; common medium prominent strong brown (7.5YR 5/6) redoximorphic concentrations; about 2 percent rock fragments; neutral; clear smooth boundary. (Combined thickness of the Bt horizon is 45 to 105 centimeters.)
Cg1--91 to 112 centimeters; mottled grayish brown (2.5Y 5/2) and light brownish gray (2.5Y 6/2) loam; massive; friable; few very fine roots; few fine tubular pores; many manganese concretions; many medium prominent yellowish brown (10YR 5/8) redoximorphic concentrations; about 2 percent rock fragments; slightly effervescent; moderately alkaline; clear smooth boundary.
Cg2--112 to 152 centimeters; mottled grayish brown (2.5Y 5/2) and yellowish brown (10YR 5/8) loam; massive; friable; few very fine irregular and tubular pores; about 2 percent rock fragments; slightly effervescent; moderately alkaline.
TYPE LOCATION: Major Land Resource Area (MLRA) 103-Central Iowa and Minnesota Till Prairies, Boone County, Iowa subset; about 2.5 miles southwest of Boone; located about 1,950 feet north and 1,720 feet east of the southwest corner of section 8, T. 83 N., R. 26 W.; USGS Boone West topographic quadrangle; lat. 42 degrees 0 minutes 49 seconds N. and long. 93 degrees 54 minutes 21 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Depth to carbonates--70 to 152 centimeters
Clay content of the particle-size control section (weighted average)--30 to 35 percent
Sand content of the particle-size control section (weighted average)--30 to 45 percent
Rock fragment content--1 to 8 percent, mixed lithology
A horizon:
Hue--10YR
Value--3; if cultivated, value of 3 or 4
Chroma--1 or 2
Texture--loam or silt loam
Clay content--12 to 26 percent
Sand content--10 to 45 percent
Reaction--moderately acid to neutral
E horizon:
Hue--10YR
Value--4 or 5
Chroma--1 or 2
Texture--loam or silt loam
Clay content--12 to 25 percent
Sand content--30 to 45 percent
Reaction--moderately acid or slightly acid
Bt or Btg horizon:
Hue--10YR or 2.5Y
Value--4 or 5
Chroma--2 or 3
Texture--clay loam or sandy clay loam
Clay content--25 to 38 percent
Sand content--25 to 50 percent
Reaction--strongly acid to neutral
C or Cg horizons:
Hue--10YR or 2.5Y
Value--5 or 6
Chroma--2 to 8
Texture--loam or sandy loam
Clay content--4 to 25 percent
Sand content--40 to 60 percent
Reaction--slightly alkaline or moderately alkaline
COMPETING SERIES: These are the
Great Piece,
Jimtown,
Pinicon, and
Warnut series.
Great Piece--have a sand content that averages more than 50 percent in the lower half of the series control section
Jimtown--have a clay content that averages 18 to 27 percent in the particle-size control section and have a rock fragment content that averages 15 to 60 percent in the lower third of the series control section
Pinicon--have a clay content that averages 24 to 28 percent in the particle-size control section
Warnut--have a clay content that averages 18 to 28 percent in the particle-size control section
GEOGRAPHIC SETTING:
Parent material--till
Landform--slightly convex and nearly level glaciated uplands adjacent to major streams and their tributaries
Slope--0 to 3 percent
Elevation--300 to 400 meters above sea level
Mean annual air temperature--6 to 10 degrees C
Mean annual precipitation--585 to 890 millimeters
Frost-free period--155 to 200 days
GEOGRAPHICALLY ASSOCIATED SOILS: Members of the typical catena include
Ames,
Dundas, and
Hayden soils.
Ames--are at lower landscape positions on flats or slight depressions and have a frequently saturated zone from the surface to a depth of 0.3 meters during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Dundas--are on landscape positions similar to those of the Luther soils and have a frequently saturated zone from the surface to a depth of 0.3 meters during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Hayden--are at lower landscape position on convex side slopes and do not have frequently saturated zone within a depth of 1.8 meters during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--somewhat poorly drained--a frequently saturated zone occurs at a depths between 0.3 and 1.0 meters during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Saturated hydraulic conductivity--1.00 to 10.00 micrometers per second
USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn, soybeans, small grains, and legume hay. Some areas are pastured or forested. The native vegetation is deciduous trees (oak, hickory).
DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic section--Western lake section
MLRA--Central Iowa and Minnesota Till Prairies (103)
LRR M; north-central Iowa
Extent--small
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Webster County, Iowa, 1969.
REMARKS:
Particle-size control section--the zone from a depth of 38 to 88 centimeters;
series control section--the zone from the surface to a depth of 150 centimeters.
Diagnostic horizons and features recognized in this pedon include:
Ochric epipedon--the zone from the surface of the soil to a depth of 38 centimeters (A, E1, E2, and E3 horizons);
albic horizon--the zone from a depth of 10 to 38 centimeters (E1, E2, and E3 horizons);
argillic horizon--the zone from a depth of 38 to 91 centimeters (Bt1, Bt2, Bt3, and Btg horizons);
aquic moisture regime.
Cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.
Taxonomy version--Keys to Soil Taxonomy, tenth edition, 2006.