LOCATION COULSTONE MO

Established Series
Rev. FJG-RLT
11/2021

COULSTONE SERIES

The Coulstone series consists of very deep, somewhat excessively drained soils of the uplands. Permeability is moderately rapid. These soils formed in colluvium and residuum from acid sandstone with lenses of cherty limestone or cherty dolomite. Slope gradients range from 5 to 60 percent. Mean annual temperature is about 55 degrees F, and mean annual precipitation is 44 inches.

TAXONOMIC CLASS: Loamy-skeletal, siliceous, semiactive, mesic Typic Paleudults

TYPICAL PEDON: Coulstone very gravelly silt loam - on a south-facing slope of 7 percent under mixed hardwoods at an elevation of 1260 feet. (Colors are for moist conditions unless otherwise stated.)

Oi--0 to 1 inch; loose pine needles and oak leaves. Some partially decomposed; many fine roots on surface. (1/2 to 2 inches thick)

A--1 to 2 inches; dark gray (10YR 4/1) very gravelly silt loam, light gray (10YR 7/2) dry; weak fine granular structure; very friable; 50 percent chert and sandstone gravel; extremely acid; clear smooth boundary. (1 to 4 inches thick)

E1--2 to 5 inches; dark grayish brown (10YR 4/2) very gravelly silt loam; weak fine granular structure; very friable; 45 percent chert and sandstone gravel; extremely acid; clear smooth boundary.

E2--5 to 12 inches; brown (10YR 5/3) very gravelly silt loam; weak fine granular structure; very friable; 40 percent chert and sandstone gravel; strongly acid; gradual smooth boundary.

E3--12 to 19 inches; brown (10YR 5/3) very gravelly loam; weak fine granular structure; friable; 40 percent chert and sandstone gravel and 10 percent chert and sandstone cobbles; strongly acid; clear smooth boundary. (Combined thickness of the E horizon is 10 to 28 inches.)

Bt1--19 to 27 inches; yellowish brown (10YR 5/4) very gravelly sandy loam; weak medium and coarse angular blocky structure; friable; reddish brown and yellowish red stains which appear to be clay films lining tubular pores and on sand particles; 50 percent chert and sandstone gravel and 10 percent chert and sandstone cobbles; very strongly acid; gradual smooth boundary.

Bt2--27 to 38 inches; very pale brown (10YR 7/4) very gravelly sandy loam; weak medium and coarse angular blocky structure; firm; thin, many faint reddish brown clay films on faces of peds; 50 percent chert and sandstone gravel and 5 percent sandstone cobbles; very strongly acid; clear smooth boundary. (combined thickness of the Bt horizon is 7 to 36 inches.)

2Bt3--38 to 53 inches; reddish brown (5YR 4/4) very gravelly clay loam; weak fine subangular blocky structure; firm; few faint reddish brown clay films on faces of peds; 45 percent sandstone gravel and 10 percent sandstone cobbles; very strongly acid; clear smooth boundary.

2Bt4--53 to 63 inches; mottled red (2.5YR 4/8) and yellowish red (5YR 4/6) very gravelly silty clay; weak fine subangular blocky structure; many faint clay films on faces of peds; 60 percent chert gravel; very strongly acid; clear smooth boundary.

TYPE LOCATION: Dent County, Missouri; on a ridge southeast of the weather station in the Sinking Experimental Forest; 2640 feet east and 660 feet north of the southwest corner, sec. 3, T. 32 N., R. 3 W; Loggers Lake quadrangle, lat. 37 degrees 15 minutes 21 seconds N. long. 91 degrees 29 minutes 28 seconds W.

RANGE IN CHARACTERISTICS: Thickness of the solum and depth to bedrock is greater than 60 inches. These soils have both angular chert fragments and rounded sandstone fragments up to 24 inches in diameter. Bouldery or stony phases are allowed. Rock fragment content ranges from 15 to 75 percent and of this up to 30 percent may be larger than 3 inches.

The A horizon has hue of 10YR or 7.5YR, value of 3 to 5, and chroma of 1 to 4. The AE and E horizons have hue of 10YR or 7.5YR, value of 4 to 6, and chroma of 2 to 4. They are the gravelly, very gravelly or extremely gravelly analogues of loam, sandy loam, fine sandy loam or silt loam. Reaction is strongly acid to extremely acid.

The Bt horizon has hue of 10YR to 5YR, value of 3 to 7 and chroma of 3 to 8. It is the very gravelly or very stony analogues of sandy loam or loam. Reaction is extremely acid to moderately acid.

The 2Bt horizon has hue of 10R to 10YR, value of 4 to 6, and chroma of 4 to 8. It is the gravelly or very gravelly analogues of clay loam, silty clay, clay, sandy clay, or sandy clay loam. Reaction is extremely acid to strongly acid.

COMPETING SERIES: These are the Bouldin and Clarksville series. The Bouldin soils do not have coarse fragments of chert. Clarksville soils have control sections with less than 35 percent sand content coarser than very fine and are dominated by chert gravel.

GEOGRAPHIC SETTING: The Coulstone soils are on steep side slopes and narrow ridgetops. They formed in a thick regolith from acid sandstones with lenses of cherty limestones or cherty dolomites. Slope gradients range from about 5 to 60 percent. Mean annual temperature ranges from 54 to 57 degrees F, and mean average annual precipitation ranges from 40 to 45 inches.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Clarksville soils and the Bender, Hobson, Lebanon, Nixa, and Plato soils. Clarksville soils are on similar landscapes. Bender soils are moderately deep over bedrock and on similar positions. Hobson, Lebanon, Nixa, and Plato soils have fragipans and commonly are on less sloping higher landscape positions.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained. Runoff is medium to high. Permeability is moderately rapid.

USE AND VEGETATION: Native vegetation is oak or oak/pine forest. Some areas are used for pasture and small areas are cropped to corn, small grain, and sorghum.

DISTRIBUTION AND EXTENT: Coulstone soils are in the Ozark Highland region (MLRA 116A) in southern Missouri. The series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia

SERIES ESTABLISHED: Dent County, Missouri, 1972.

REMARKS: Diagnostic horizons and features recognized in this series are: ochric epipedon - the zone from the surface of the soil to a depth of 19 inches (Oi, A, E1, E2, and E3 horizons);
argillic horizon - the zone from approximately 19 to 63 inches or more (Bt1, Bt2, 2Bt3, and 2Bt4 horizons);
udic moisture regime.

National Cooperative Soil Survey
U.S.A.