LOCATION KNIGHT IL

Established Series
Rev. GOW-JCD-WMT
01/2011

KNIGHT SERIES

The Knight series consists of very deep, poorly drained soils. Knight soils are on outwash plains, stream terraces and flood plain steps. Knight soils formed in loess or silty material and are underlain by loamy or coarser textured outwash. Slope is usually less than 2 percent. Mean annual temperature is about 11.1 degrees C (52 degrees F), and mean annual precipitation is about 965 mm (38 inches) near the type location.

TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Argiaquic Argialbolls

TYPICAL PEDON: Knight silt loam - on a south facing slope about 1 percent in a cultivated field at an elevation of about 162 meters (530 feet) above mean sea level. (Colors are for moist soil.)

Ap--0 to 25 centimeters (0 to 10 inches); black (10YR 2/1) silt loam; moderate very fine subangular blocky structure (compacted); friable; few fine roots; neutral; abrupt smooth boundary. [Combined thickness of the A horizons is 25 to 61 centimeters (10 to 24 inches).]

Eg--25 to 41 centimeters (10 to 16 inches); gray (10YR 5/1) silt loam; moderate medium platy structure; friable; few fine roots; few distinct dark grayish brown (10YR 4/2) organic stains on faces of peds; few fine distinct dark brown (7.5YR 3/4) extremely weakly cemented iron-manganese oxides in the matrix; neutral; clear smooth boundary. [Combined thickness of the Eg horizons is 13 to 51 centimeters (5 to 20 inches).]

BEg--41 to 56 centimeters (16 to 22 inches); light brownish gray (2.5Y 6/2) silt loam; moderate coarse platy structure parting to moderate fine subangular blocky; friable; few fine roots; few distinct dark grayish brown (10YR 4/2) organic stains on faces of peds; few fine prominent dark brown (7.5YR 3/4) extremely weakly cemented iron-manganese oxides in the matrix; neutral; gradual smooth boundary. [0 to 23 centimeters (0 to 9 inches) thick]

Btg1--56 to 89 centimeters (22 to 35 inches); light brownish gray (2.5Y 6/2) silty clay loam; moderate medium prismatic structure parting to moderate medium subangular blocky; friable; few faint gray (2.5Y 6/1) silt coats on faces of peds, common distinct grayish brown (10YR 5/2) clay films on faces of peds and few distinct dark grayish brown (10YR 4/2) clay films on surfaces along pores; few fine distinct black (7.5YR 2.5/1) iron-manganese concretions in the matrix and few fine prominent strong brown (7.5YR 4/6) extremely weakly cemented iron-manganese oxides in the matrix; slightly acid; gradual smooth boundary.

Btg2--89 to 135 centimeters (35 to 53 inches); varigated strong brown (7.5YR 5/6) and (7.5YR 4/6) and light brownish gray (2.5Y 6/2) silty clay loam; weak coarse prismatic structure; friable; few faint gray (2.5Y 6/1) silt coats on faces of peds; few distinct grayish brown (10YR 5/2) clay films on faces of peds and few distinct dark grayish brown (10YR 4/2) clay films on surfaces along pores; few fine distinct black (7.5YR 2.5/1) iron-manganese concretions in the matrix; slightly acid; gradual smooth boundary. [Combined thickness of the Btg horizon is 56 to 89 centimeters (22 to 35 inches).]

BCg--135 to 178 centimeters (53 to 70 inches); varigated light brownish gray (2.5Y 6/2) and strong brown (7.5YR 5/6) and (7.5YR 4/6) silt loam; weak coarse prismatic structure; friable; few distinct dark grayish brown (10YR 4/2) clay films on surfaces along pores; few fine distinct black (7.5YR 2.5/1) iron-manganese concretions and few fine distinct strong brown (7.5YR 4/6) masses of oxidized iron in the matrix; neutral; abrupt smooth boundary. [0 to 51 centimeters (0 to 20 inches) thick]

2Cg1--178 to 201 centimeters (70 to 79 inches); grayish brown (10YR 5/2) stratified sandy clay loam and sandy loam; massive; friable; few fine prominent strong brown (7.5YR 4/6) masses of oxidized iron and few fine distinct black (7.5YR 2.5/1) iron-manganese concretions in the matrix; 5 percent gravel; neutral; gradual smooth boundary.

2Cg2--201 to 224 centimeters (79 to 88 inches); dark grayish brown (10YR 4/2) gravelly sandy clay loam; massive; friable; few fine distinct black (7.5YR 2.5/1) iron-manganese concretions and few fine prominent strong brown (7.5YR 4/6) extremely weakly cemented iron-manganese oxides in the matrix; 15 percent gravel, neutral.

TYPE LOCATION: Logan County, Illinois; about 4 miles south east of Lawndale, 330 feet north and 2170 feet east of the southwest corner of sec. 9, T.20 N., R.1W.; lat. 40 degrees 11 minutes 39 seconds N. and long. 89 degrees 12 minutes 53 seconds W. or UTM zone 16 311490E 4451657N, NAD 83

RANGE IN CHARACTERISTICS:
Thickness of the mollic epipedon: 25 to 61 cm (10 to 24 inches)
Depth to the top of the argillic horizon: greater than 51 cm (20 inches)
Depth to the base of the argillic horizon: 114 to 152 cm (45 to 60 inches), some pedons have development into the underlying loamy or coarse textured material.
Particle size control section: averages 27 to 35 percent clay. The soil horizons to a depth of 137 cm (54 inches) have less than 10 percent sand. Sand content in the underlying material ranges from 15 to 95 percent.
Depth to carbonates: greater than 137 cm (54 inches)

Ap and A horizons
Hue: 10YR
Value: 2 or 3
Chroma: 1 or 2
Texture: silt loam
Reaction: strongly acid to neutral

Eg and/or BEg horizons:
Hue: 10YR. 2.5Y or 5Y
Value: 4 to 6
Chroma: 2 or less, the lower part commonly has redox accumulations of higher chroma.
Texture: silt loam
Reaction: strongly acid to neutral

Btg and/or BCg horizons;
Hue: 10YR, 2.5Y or 5Y
Value: 4 to 6
Chroma: 2 or less, redoximorphic features have higher chroma.
Texture: dominantly silty clay loam, but is silt loam in the upper or lower parts in some pedons.
Content of clay: 22 to 35 percent
Reaction: strongly acid to neutral

Some pedons have a 2BCg horizon with colors similar to the 2C or 2Cg horizons.

2C or 2Cg horizon:
Hue: 10YR, 2.5Y or 5Y
Value: 4 to 6
Chroma: 1 to 6
Texture: typically stratified sandy clay loam, sandy loam, silt loam, loam, sand, or their gravelly or very gravelly analogues. Content of clay: 5 to 30 percent
Rock fragments: 0 to 60 percent
Reaction: slightly acid to moderately alkaline
Carbonates: present in some pedons

COMPETING SERIES: These are the Corley, Ebbert, Edgington, Marissa, Normal, Speed, Thorp, and Vesser series. Corley soils have part of the mollic epipedon below the albic horizon. Ebbert, Marissa, and Speed soils have mean annual soil temperature of more than 12.8 degrees C (55 degrees) in the soil temperature control section. Edgington soils do not have loamy materials within a depth of 183 cm (72 inches). Normal soils have a matrix color with greater than 2 chroma in one or more horizons in the upper part of the series control section. Thorp soils have horizons with more than 10 percent sand within a depth of 137 cm (54 inches). Vesser soils contain more than 10 percent sand in the upper part of the series control section.

GEOGRAPHIC SETTING: Knight soils are on outwash plains, stream terraces, and flood plain steps. Slope is usually less than 2 percent. They formed in less than 183 cm (72 inches) of loess or silty material and are underlain by loamy or coarse textured outwash. Mean annual air temperature ranges from about 9.4 to 14.4 degrees C (49 to 58 degrees F), and annual precipitation ranges from about 610 to 1295 mm (24 to 51 inches) near the type location.

GEOGRAPHICALLY ASSOCIATED SOILS: They are the Elburn, Plano, Proctor, and Tama soils. All lack E horizons, are better drained, and are at somewhat higher elevations in the same general landscape.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Poorly drained. Potential for surface runoff is negligible. Saturated hydraulic conductivity is moderately high to high (1.41 to 14.11 micrometers per second) in the upper part of the solum and moerately high to high (4.23 to 42.34 micrometers per second) in the lower part of the solum and substratum. Permeability is moderately slow or moderate in the upper part of the solum and moderate to moderately rapid in the lower part of the solum and in the substratum. In normal years, the apparent seasonal high water table is at the surface to 31 cm (1 foot) below the surface in spring. Ponding depth is generally less than 15 cm (0.5 foot) above the surface. A rarely flooded phase has is recognized.

USE AND VEGETATION: Most areas are cultivated. Principal crops are corn, soybeans, and small grains. Native vegetation is prairie grasses tolerant of prolonged periods of wetness.

DISTRIBUTION AND EXTENT: Central and northeastern Illinois. The extent is small in MLRAs 95B, 108A, and 108B

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana

SERIES ESTABLISHED: Kendall County, Illinois, 1941.

REMARKS: With this update (3/2006) the type location is relocated to a new site. Diagnostic horizons and features recognized in this pedon are: Mollic epipedon -- the zone from the surface to a depth of 25 centimeters (10 inches) Albic horizon -- the zone from 25 to 56 centimeters [10 to 22 inches (Eg and BEg horizons)] Argillic horizon -- the zone from 56 to 135 centimeters [22 to 53 inches (Btg1 and Btg2 horizon)]

National Cooperative Soil Survey
U.S.A.