LOCATION LENZBURG IL+MO

Established Series
Rev. RDW-JWC-RAL
03/2020

LENZBURG SERIES

The Lenzburg series consists of very deep, well drained soils on surface-mined areas. These soils formed in materials that have been excavated during surface mining operations. Some areas have been graded. The regolith dominantly is fine earth material that contains till pebbles or fragments of bedrock that are shale, siltstone, sandstone, or limestone. Slope ranges from 0 to 70 percent. Mean annual precipitation is about 38 inches, and mean annual temperature is about 53 degrees F.

TAXONOMIC CLASS: Fine-loamy, spolic, mixed, active, calcareous, mesic Anthroportic Udorthents

TYPICAL PEDON: Lenzburg silt loam - on a graded area with a 4 percent convex slope in a field of fescue and alfalfa. (Colors are for moist soils unless otherwise stated.)

Ap--0 to 3 inches (0 to 8 cm); mixed brown (10YR 4/3), light brownish gray (10YR 6/2), yellowish brown 10YR 5/6), and yellowish red (5YR 5/6) silt loam; pale brown (10YR 6/3) dry; weak fine granular structure; friable, slightly hard; about 7 percent rock fragments of till pebbles and channers and flags of limestone and siltstone; slightly effervescent; slightly alkaline; abrupt wavy boundary. (Thickness ranges from 0 to 10 inches.)

AC--3 to 6 inches (8 to 15 cm); mixed yellowish brown (10YR 5/4), light brownish gray (10YR 6/2), and strong brown (7.5YR 5/6) silt loam; moderate medium platy structure; friable, hard and slightly hard; about 9 percent rock fragments of till pebbles and channers and flags of limestone and siltstone; strongly effervescent; slightly alkaline; abrupt wavy boundary. (Thickness ranges from 0 to 10 inches.)

C1--6 to 10 inches (15 to 25 cm); brown (10YR 4/3) silt loam; strong thick horizontal layers; massive; firm, hard; few light brownish gray (10YR 6/2) silty clay loam soil fragments; few distinct very dark gray (10YR 3/1) coatings on faces of soil fragments; about 11 percent rock fragments of till pebbles and channers and flags of limestone and siltstone; strongly effervescent; slightly alkaline; abrupt wavy boundary.

C2--10 to 33 inches (15 to 84 cm); mixed brown (7.5YR 4/4) and pale brown (10YR 6/3) clay loam; massive; firm, hard; few vertical cleavage planes; few gray (10YR 5/1) soil fragments throughout, and few yellowish red (5YR 5/6) soil fragments in the lower part; about 9 percent rock fragments of till pebbles and channers and flags of limestone and siltstone; strongly effervescent; slightly alkaline; clear smooth boundary.

C3--33 to 45 inches (84 to 114 cm); mixed dark yellowish brown (10YR 4/4) and pale brown (10YR 6/3) clay loam; massive; firm, hard; few gray (10YR 6/1) and grayish brown (10YR 5/2) soil fragments; about 10 percent rock fragments of till pebbles and channers and flags of limestone and siltstone; strongly effervescent; slightly alkaline; clear smooth boundary.

C4--45 to 60 inches (114 to 152 cm); mixed brown (7.5YR 4/4) and gray (10YR 5/1) channery clay loam; very firm, very hard; few yellowish red (5YR 5/8) soil fragments; about 17 percent rock fragments of limestone; strongly effervescent; slightly alkaline.

TYPE LOCATION: Lenzburg silt loam, 1 to 7 percent slopes, at an elevation of 525 feet; Randolph County, Illinois; approximately 12 feet south and 580 feet east of the center of sec. 22, T. 5 S., R. 6 W.; USGS Steeleville, IL. topographic quadrangle; lat. 38 degrees 4 minutes 55 seconds N. and long. 89 degrees 44 minutes 54 seconds W. or UTM zone16 258966E 4218479N, NAD 83.

RANGE IN CHARACTERISTICS: The individual subhorizons within the C horizon are variable in thickness. Content of rock fragments in the particle-size control section averages from 5 to 35 percent by volume. Rock fragments are disordered relative to any plane in the profile and commonly are gravel and cobbles, but include stones and small boulders. Between 5 and 15 percent of the rock fragments are 3 inches in diameter or larger. In a few pedons, bridging of rock fragments by fine earth material forms small voids. Soil fragments and isolated peds of relict genetic horizons of pre-mined soils are randomly distributed throughout and also are disordered relative to any plane in the profile. Soil fragments have identifiable properties such as redoximorphic features, clay films, or coatings that are characteristic of their previous formation. The series control section is neutral to moderately alkaline and contains carbonates. The organic carbon content decreases irregularly with depth because of mixing and the presence of coal and other carbonaceous material. Depth to bedrock is more than 6 feet.

The A horizon has hue of 5YR, 10YR, 2.5Y, or 5Y; value of 2 to 6 (4 to 7 dry); and chroma typically of 2 to 4 but ranging from 1 to 6. Dark coatings are on the faces of peds in some pedons. The A horizon is silt loam, silty clay loam, clay loam, or loam; or the gravelly, stony, or channery analogs. Typically it has weak or moderate, fine or medium structure.

The C horizon has a wide range of colors. Dominant colors are in hue of 7.5YR or 10YR, value of 4 to 6, and chroma of 1 to 6. Some pedons have color value of 2 or 3 (see remarks). Some included peds or soil fragments are grayer and some are browner than these colors. Redoximorphic iron depletions with chroma of 2 or less are relict and not indicative of soil drainage. They occur at random depth, spacing, and orientation in the soil. The C horizon is silty clay loam, silt loam, loam, silty clay, or clay loam; or the channery, gravelly, or cobbly analogs. Thin strata or small pockets of coarser or finer textured material are in some pedons. In some pedons there is evidence of weakly expressed post-mining genetic soil structure in the upper part of the C horizon or in an AC horizon. Some of the included peds or soil fragments of previous genetic horizons do not contain carbonates. Stony phases are recognized. An acid substratum phase has been recognized, where, below a depth of 48 inches, it contains refuse material from the coal washing operation.

COMPETING SERIES: This is the Lenzwheel series. Schuline series is in a closely related family. Lenzwheel soils have less than 5 percent rock fragments in the particle-size control section that are 3 inches in diameter or larger. Schuline soils have a superactive cation-exchange activity class.

GEOGRAPHIC SETTING: Lenzburg soils are on crests and slopes of cast overburden material from surface mining. Slope gradients commonly are 3 to 30 percent and range from 0 to 70 percent. The soils formed in regolith that consists of a mixture that is dominated by calcareous loamy till and contains components of loess and residuum of weathered interbedded siltstone, sandstone, shale, or limestone. Some areas contain refuse material from coal processing, locally known as gob or slurry, in the substratum at a depth of 48 inches or more. Mean annual precipitation is 34 to 42 inches, and mean annual temperature is 48 to 57 degrees F., frost-free period is 160 to 200 days, and elevation is 350 to 1,000 feet above mean sea level.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Morristown and Rapatee soils on surface-mined areas, and the Darmstadt, Elco, Hickory, Ipava, Marseilles, Sable, and Stoy soils on adjacent or nearby undisturbed areas. Morristown soils contain more rock fragments throughout and are on similar nearby areas. Rapatee soils are on nearby areas that have had the darkened surface layers of pre-mined soils replaced at the surface. Darmstadt, Ipava, Sable, and Stoy soils are on nearby level or gently sloping summits and interstream divides. Elco soils are on side slopes of drainageways and on some ridgetops. Hickory and Marseilles soils are on side slopes of valleys and incised drainageways.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained. The potential for surface water runoff is low to very high. Saturated hydraulic conductivity is moderately high (1.41 to 4.23 micrometers/second). Permeability is moderately slow.

USE AND VEGETATION: Many areas that have a stony surface or steep slopes are seeded to grass-legume mixtures or fescue and are used for pasture. Other areas have a mixture of deciduous trees, or are in pine plantations and are used for recreation or wildlife habitat. Some areas have been graded and used for meadow, small grain, or row crops.

DISTRIBUTION AND EXTENT: Illinois and Missouri and possibly in Indiana, Kentucky, and Ohio; extent is moderate, and mainly in MLRA(s) 108A, 108B, 113, 114B, 115B and 115C.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Indianapolis, Indiana

SERIES ESTABLISHED: Henry County, Illinois, 1981.

REMARKS: These soils were formerly mapped as mine spoils, strip mines, Orthents, or other miscellaneous categories. Soil colors with value of 2 or 3 result from finely divided coal or black shale and are not result of current genetic soil development.

Diagnostic horizons and features in this pedon include:
Ochric epipedon - 0 to 6 inches (Ap and AC horizons).

03/2020 Updated Taxonomic Class based on Keys to Soil Taxonomy, Twelfth Edition, 2014.

ADDITIONAL DATA: Data for several pedons in Illinois have been collected and are on file at the NRCS state office in Champaign, Illinois.

National Cooperative Soil Survey
U.S.A.