LOCATION HAMMACK KY+TNEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, semiactive, mesic Glossic Paleudalfs
TYPICAL PEDON: Hammack silt loam, on a smooth convex 4 percent slope. (Colors are for moist soil.)
Ap--0 to 8 inches; brown (10YR 4/3) silt loam; weak fine granular structure; very friable; common fine roots; neutral; abrupt smooth boundary. (5 to 10 inches thick)
Bt--8 to 28 inches; brown (7.5YR 4/4) light silty clay loam; moderate fine and medium subangular blocky structure; friable; few fine roots; few fine pores; few clay films; medium acid; abrupt smooth boundary. (15 to 30 inches thick)
2B/E--28 to 42 inches; brown (7.5YR 4/4) extremely gravelly clay loam; few fine faint yellowish red mottles; weak fine subangular blocky structure; firm; few clay films; 70 percent fragments of chert, one-half are smaller than three inches; E portion makes up about 10 percent and consists of light brownish gray (10YR 6/2) and pale brown (10YR 6/3) silt coatings around fragments of chert and some peds; few fine black concretions; strongly acid; clear smooth boundary. (5 to 25 inches thick)
2Bt1--42 to 55 inches; red (2.5YR 4/6) very gravelly silty clay; common fine distinct strong brown mottles; moderate fine and very fine angular blocky structure; firm; few fine pores; many clay films; 40 percent fragments of chert, one-half are smaller than three inches; few fine black concretions; very strongly acid; clear smooth boundary. (0 to 20 inches thick)
2Bt2--55 to 84 inches; red (2.5YR 4/6) gravelly clay; common medium prominent very pale brown (10YR 7/4), pinkish gray (7.5YR 7/2), reddish yellow (7.5YR 6/6) and few medium faint reddish brown mottles; moderate medium parting to fine and very fine angular blocky structure; very firm; few fine pores; many clay films; 15 percent fragments of chert, one-half are smaller than three inches; few fine black concretions; very strongly acid.
TYPE LOCATION: Todd County, Kentucky; 100 yards north of farm road and 100 yards west of large pond, 1 mile west of Kentucky 104, 4.5 miles south of Trenton, about 9 miles southwest of Elkton.
RANGE IN CHARACTERISTICS: The solum thickness ranges from 6 to more than 10 feet. Depth to limestone ranges from 8 to 30 feet. The soil ranges from medium acid to very strongly acid, except where limed; the Ap and upper B horizons range to neutral. The upper solum formed in loess and ranges from about 20 to 40 inches thick. Fragments of chert range from 0 to 5 percent in the upper sola, from 35 to 80 percent in the 2B/E horizon, and from 0 to 80 percent in individual horizons of the 2Bt with a weighted average of 15 to 50 percent.
The A horizon has hue of 10YR or 7.5YR, values of 4 or 5, and chroma of 2 to 4. It is a silt loam or silty clay loam. It has weak fine or medium granular and/or subangular blocky structure.
Some pedons have BE horizons 3 to 8 inches thick with colors and textures like that of the A horizon.
The Bt horizon has hue of 7.5YR or 5YR, values of 4 or 5, and chroma of 4 or 6. Some pedons are mottled in shades of brown and in the lower few inches shades of gray. The texture is silty clay loam or silt loam. It has weak or moderate, medium fine or very fine, subangular or angular blocky structure and is friable or firm.
The 2B/E horizon has hue of 10YR, 7.5YR, or 5YR; values of 4 or 5; and chroma of 4 or 6. Some pedons are mottled in shades of brown and gray. It is gravelly, or very gravelly or extremely gravelly silt loam and gravelly, very gravelly, or extremely gravelly silty clay loam. It has weak or moderate, medium to very fine subangular and angular blocky structure and is firm and/or brittle. The E portions are silt coatings that constitute from 5 to 15 percent of the horizon. It has hue of 10YR or 7.5YR, values of 6 or 7, and chroma of 1 through 4.
The 2Bt horizon has hue of 5YR or 2.5YR, values of 3 through 5, and chroma of 4 or 6, and has few or common mottles in shades of yellow, brown, gray, or red. It is commonly clay or silty clay, and their gravelly or very gravelly analogues. Some pedons have subhorizons of clay loam or rarely silty clay loam and their gravelly analogues. It has moderate or strong, very fine through coarse angular blocky structure and is firm or very firm.
Some pedons have 2C horizons with a matrix and mottles in shades of yellow, brown, red, or gray and textures like the 2Bt horizons.
COMPETING SERIES: The Fourche series is the only cometing series in the same family. Similar soils are the Crider, Evangeline, Mountview, and Pembroke series. Fourche soils have less than 15 percent fragments in the 2B horizon. Crider soils have less than 15 percent chert in the 2B horizons. Evangeline soils lack 2B horizons formed in cherty limestone residuum and have thermic soil temperatures. Pembroke soils have values of 2 or 3 in the Ap horizons. Mountview soils have less than 35 percent base saturation and have a thermic soil temperature regime.
GEOGRAPHIC SETTING: Hammack soils are on ridgetops and sideslopes. Slopes range from 2 to 60 percent. Some areas have karst topography. The regolith is 20 to 40 inches of loess, over residuum from cherty limestone. These soils are in areas having 45 to 50 inches annual precipitation which is normally evenly distributed throughout the year. The average annual air temperature ranges from 54 degrees to 59 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Crider and Pembroke series and the Baxter and Nicholson series. Baxter soils have more than 35 percent clay and 15 to 35 percent chert in the upper 20 inches of the argillic horizon. Nicholson soils have fragipans.
DRAINAGE AND PERMEABILITY: Well drained, runoff is medium or rapid. Permeability is moderate.
USE AND VEGETATION: Most areas are used for hay, pasture, small grain, corn, soybeans, and tobacco. Some of the steeper areas are in forest consisting of oak, hickory, gum, maple, hackberry, and poplar.
DISTRIBUTION AND EXTENT: The Pennyroyal region of Kentucky. The extent is moderate.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Christian County, Kentucky; 1977.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: 0 to 8 inches (Ap)
Argillic horizon: 8 to 84 inches (Bt, 2B/E, 2Bt1, & 2Bt2)
Skeletans present in 2B/E horizon.