LOCATION RUBIO                   IA+IL

Established Series
Rev. JAL-JWH-RJB
06/2015

RUBIO SERIES


The Rubio series consists of very deep, poorly and very poorly drained soils formed in loess on uplands and high stream terraces. They are slowly permeable. Slopes range from 0 to 2 percent. Mean annual temperature is about 51 degrees F, and mean annual precipitation is about 33 inches.

TAXONOMIC CLASS: Fine, smectitic, mesic Vertic Albaqualfs

TYPICAL PEDON: Rubio silt loam - on a nearly level upland divide in a cultivated field. (Colors are for moist soil unless otherwise stated.)

Ap-- 0 to 8 inches; very dark gray (10YR 3/1) silt loam, very dark grayish brown (10YR 3/2) kneaded, gray (10YR 5/1) dry; 5 percent streaks and pockets of grayish brown (10YR 5/2) subsurface material; weak fine subangular blocky structure parting to weak fine granular; friable; few fine roots; few fine tubular pores; neutral; abrupt smooth boundary. (6 to 9 inches thick)

E-- 8 to 14 inches; dark gray (10YR 4/1) and grayish brown (10YR 5/2) silt loam, white (10YR 8/1) dry; moderate medium platy structure; friable; few fine roots; few fine tubular pores; few fine distinct dark yellowish brown (10YR 4/4) redox concentrations; few fine irregular masses of iron-manganese; slightly acid; clear smooth boundary. (4 to 10 inches thick)

Btg1--14 to 18 inches; dark gray (10YR 4/1) and gray (10YR 5/1) silty clay loam; strong very fine subangular blocky structure; friable; few fine roots; few fine tubular pores; few faint dark gray (10YR 4/1) clay films on faces of peds; common fine distinct dark yellowish brown (10YR 4/4) redox concentrations; few fine irregular masses of iron-manganese; slightly acid; gradual smooth boundary.

Btg2--18 to 22 inches; dark gray (5Y 4/1) silty clay loam; moderate medium prismatic structure parting to strong very fine subangular blocky; firm; few fine roots; few fine tubular pores; common distinct olive gray (5Y 4/2) clay films on faces of peds; few fine prominent strong brown (7.5YR 5/8), common fine prominent yellowish brown (10YR 5/8), and common fine prominent light olive brown (2.5Y 5/6) redox concentrations; few fine irregular masses of iron-manganese; moderately acid; gradual smooth boundary.

Btg3--22 to 30 inches; gray (5Y 5/1) silty clay; moderate medium prismatic structure parting to strong very fine subangular blocky; firm; few fine roots; few fine tubular pores; common distinct olive gray (5Y 4/2) clay films on faces of peds; common fine prominent light olive brown (2.5Y 5/4) and common fine prominent yellowish brown (10YR 5/8) redox concentrations; few fine irregular masses of iron-manganese; moderately acid; gradual smooth boundary.

Btg4--30 to 39 inches; olive gray (5Y 5/2) and light olive gray (5Y 6/2) silty clay loam; moderate medium prismatic structure parting to moderate fine subangular blocky; firm; few fine roots; few fine tubular pores; common distinct olive gray (5Y 4/2) clay films on faces of peds; common fine prominent light olive brown (2.5Y 5/6) and common fine prominent yellowish brown (10YR 5/8) redox concentrations; few fine irregular masses of iron-manganese; moderately acid; gradual smooth boundary.

Btg5--39 to 46 inches; olive gray (5Y 5/2) silty clay loam; weak medium prismatic structure parting to moderate fine subangular blocky; friable; few fine roots; few fine tubular pores; common distinct olive gray (5Y 4/2) clay films on faces of peds; few fine prominent light olive brown (2.5Y 5/6) and few fine distinct olive (5Y 5/4) redox concentrations; few fine irregular masses of iron-manganese; moderately acid; gradual smooth boundary. (Combined thickness of the Btg horizons is 22 to 37 inches.)

BCg--46 to 60 inches; olive gray (5Y 5/2) silty clay loam; weak medium prismatic structure parting to weak medium subangular blocky; friable; few faint dark gray (10YR 4/1) clay films on faces of peds; common fine prominent light olive brown (2.5Y 5/6) and common fine prominent yellowish brown (10YR 5/8) redox concentrations; few fine irregular masses of iron-manganese; slightly acid; gradual smooth boundary. (0 to 16 inches thick)

Cg--60 to 80 inches; olive gray (5Y 5/2) silty clay loam; massive; friable; common fine prominent light olive brown (2.5Y 5/6) and common fine prominent yellowish brown (10YR 5/8) redox concentrations; few fine irregular masses of iron-manganese; neutral.

TYPE LOCATION: Keokuk County, Iowa; about 6 miles west of Keota; 1800 feet west and 220 feet north of the southeast corner of section 24, T. 76 N., R. 11 W. U.S.G.S. Harper, Iowa - Iowa Topographic Quadrangle; latitude 41 degrees, 22 minutes, and 1 seconds N., longitude 92 degrees, 4 minutes, and 15 seconds W.

RANGE IN CHARACTERISTICS: Solum thickness typically is more than 48 inches, and it ranges from 42 to 72 inches. Carbonates are lacking to depths of 60 or more inches. These soils are moderately acid or strongly acid in the most acid part.

The A or Ap horizons have hue of 10YR, value of 3, and chroma of 1 or 2. Texture is silt loam.

The E horizon has hue of 10YR, value of 4 or 5, and chroma of 1 or 2. Texture is silt loam.

The Btg horizon has hue of 10YR, 2.5Y, or 5Y, value of 4 or 5, and chroma of 1, or is olive gray (5Y 5/2). Redox concentrations have 7.5YR, 10YR, 2.5Y or 5Y hue; value of 4 through 6; and chroma of 3 through 8. Redox depletions of 10YR, 2.5Y, or 5Y hue, value of 4 to 6, and chroma of 1 or 2 are evident in interiors of peds in the lower part of the Btg horizon. The upper part of the argillic horizon contains 35 to 42 percent clay. Textures are silty clay loam or silty clay. Some coatings of silt are evident in the upper part of the Btg horizon.

The BCg and C horizons have hue of 5Y, value of 4 or 5, and chroma of 1 or 2. The BCg and C horizons are silty clay loam with clay content ranging from 32 to 38 percent.

COMPETING SERIES: These are the Adco, Appanoose, Awbrig, Belinda. Brooklyn, Chariton, Cisne, Cowden, Denny, Glensted, Putnam, and Wagner series. Adco, Appanoose, Awbrig, Belinda, Chariton, Glensted, and Putnam soils average more than 42 percent clay in the particle size control section. Brooklyn and Cisne soils contain more sand in the sola. Cowden soils contain layers below the sola that contain more sand. Denny soils average less than 32 percent clay in the lower part of the control section. Wagner soils have strata in the lowest part of the control section with as much as 90 percent sand.

GEOGRAPHIC SETTING: Rubio soils are in slight depressions or on nearly level, broad, upland divides, and on broad, nearly level high stream terraces. Slopes are less than 2 percent. Rubio soils formed in loess of Wisconsin age which ranges from 10 to 16 feet in thickness and contains less than 5 percent sand. Carbonates are usually lacking in the loess, but thin, discontinuous layers of secondary carbonates are below a depth of 60 inches in some places. Mean annual air temperature ranges from about 50 to 52 degrees F, and mean annual precipitation ranges from 32 to 34 inches. The annual frost free period ranges from about 155 to 180 days. Elevation ranges from about 650 to 1350 feet above mean sea level.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Givin and Ladoga soils. The somewhat poorly drained Givin soils are on the nearly level divides and high stream benches and generally border the Rubio soils. The moderately well drained Ladoga soils are on convex slopes at lower elevations.

DRAINAGE AND PERMEABILITY: Rubio soils are poorly or very poorly drained. The poorly drained areas are on the nearly level broad divides and the very poorly drained areas are in depressions. Surface runoff typically is very slow, and permeability is slow. The intermittent perched seasonal high water table is +.5 to 1 foot for some time from November through July during most years.

USE AND VEGETATION: Commonly used for cultivated crops. Corn, soybeans, small grains, and meadow are grown. Native vegetation was both trees and prairie grasses. See Additional Data section for native vegetative cover in Iowa.

DISTRIBUTION AND EXTENT: Southeastern Iowa. They are inextensive and are in MLRA 108 and 109.

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

SERIES ESTABLISHED: Jefferson County, Iowa, 1957.

REMARKS: Diagnostic horizons and features recognized in this pedon are: ochric epipedon - the zone from the surface to a depth of 14 inches (Ap and E horizons); albic horizon - the zone from approximately 8 to 14 inches (E horizon); argillic horizon - the zone from approximately 14 to 46 inches (Btg1, Btg2, Btg3, Btg4, and Btg5 horizons); udic moisture regime.

ADDITIONAL DATA: In Iowa, the native vegetative cover is a mixed herbaceous and woody community commonly inhabited with Green Ashes, American Elms, Common Hackberries, Eastern Cottonwoods, American Sycamores, Silky Dogwoods, Black Willows, Wild Black Currants, Riverbank Grapes, Grays Sedges, Hop Sedges, Virginia Wildryes, Stiff Bedstraws, White Avens, Wood Nettles, False Nettles, Canadian Clearweeds, and Common Bonesets. Source: Iowa State Office, Natural Resources Conservation Service, Des Moines, IA.


National Cooperative Soil Survey
U.S.A.