LOCATION GRUBBS AR
Established Series
Rev. LBW
02/2013
GRUBBS SERIES
The Grubbs series consists of very deep, moderately well drained, very slowly permeable soils that formed in silty and clayey sediments. These soils are on escarpments and along the perimeters of late Pleistocene aged terraces in the Western Lowlands of the lower Mississippi Valley; MLRA 131. Slope ranges from 0 to 8 percent..
TAXONOMIC CLASS: Fine, mixed, active, thermic Albaquic Hapludalfs
TYPICAL PEDON: Grubbs silt loam - cultivated. (Colors are for moist soil unless otherwise stated)
Ap--0 to 5 inches; brown (10YR 4/3) silt loam; moderate medium and coarse granular structure; friable; many fine and medium roots; many medium pores; slightly acid; abrupt smooth boundary. (4 to 8 inches thick)
Bt1--5 to 12 inches; yellowish red (5YR 5/6) silty clay loam; moderate medium subangular blocky structure; friable; many fine roots; common fine and medium pores; few faint clay films lining some pores; few medium distinct pale brown (10YR 6/3) iron depletions; moderately acid; gradual wavy boundary.
Bt2--12 to 20 inches; red (2.5YR 4/6) silty clay; moderate medium subangular blocky structure; firm; common fine roots; common fine and medium pores; many distinct clay films on faces of peds and lining pores; many fine prominent light brownish gray (10YR 6/2) and few medium prominent yellowish brown (10YR 5/4) iron depletions; very strongly acid; clear wavy boundary.
Bt3--20 to 26 inches; yellowish brown (10YR 5/4) silty clay; moderate medium subangular blocky structure; firm; common fine and few medium roots; common fine and very fine and few medium pores; common distinct clay films on faces of peds and lining pores; common fine and medium distinct grayish brown (10YR 5/2) iron depletions and few medium prominent yellowish red (5YR 4/6) iron accumulations; few fine brown iron-manganese concretions; very strongly acid; clear wavy boundary. (Combined thickness of the Bt horizon ranges from 18 to 30 inches)
Btg1--26 to 40 inches; light brownish gray (10YR 6/2) silty clay loam; moderate medium subangular blocky structure; firm; common fine roots; common fine and medium pores; common distinct clay films on faces of some peds and lining pores; many medium distinct dark yellowish brown (10YR 4/4), few medium distinct strong brown (7.5YR 4/6) and few fine faint pale brown (10YR 6/3) iron accumulations; many medium distinct white (10YR 8/2) clay depletions on faces of peds in upper 5 inches; few medium prominent black (10YR 2/1) manganese accumulations on faces of peds; few medium brown iron-manganese concretions; strongly acid; clear smooth boundary.
Btg2--40 to 52 inches; grayish brown (10YR 5/2) silt loam; moderate medium subangular blocky structure; friable; few fine roots; common fine and medium pores; common distinct clay films on faces of some peds and lining pores; many medium distinct dark yellowish brown (10YR 4/4) iron accumulations and common medium pale brown (10YR 6/3) iron depletions; few fine and medium brown iron-manganese concretions; few medium prominent black (10YR 2/1) manganese accumulations on faces of some peds; strongly acid; gradual wavy boundary. (Combined thickness of the Btg horizon ranges from 24 to 36 inches.)
B't--52 to 64 inches; brown (10YR 4/3) silt loam; moderate coarse subangular blocky structure; friable; few fine roots; common very fine, fine and medium pores; common distinct clay films mainly in pores; common coarse distinct grayish brown (10YR 5/2) and few medium distinct pale brown (10YR 6/3) iron depletions; few fine and medium brown iron-manganese concretions; few medium prominent black (10YR 2/1) manganese accumulations on faces of some peds; few medium white (10YR 8/2) powdery barite masses; slightly acid; gradual smooth boundary. (0 to 15 inches thick)
BC--64 to 76 inches; brown (10YR 4/3) silt loam; moderate coarse subangular blocky structure; friable; common very fine, fine and medium pores; common coarse distinct grayish brown (10YR 5/2) and few fine distinct pale brown (10YR 6/3) iron depletions; few fine and medium brown iron-manganese concretions; few medium prominent black (10YR 2/1) manganese accumulations on ped faces; few medium white (10YR 8/2) powdery barite masses; neutral. (0 to 15 inches thick)
TYPE LOCATION: Woodruff County, Arkansas; SE1/4SE1/4NW1/4 sec. 24, T. 6 N., R. 3 W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 50 to 80 inches or more. An abrupt texture change occurs between the A or E horizon and the underlying Bt horizon. Reaction is moderately acid or slightly acid in the A horizon, very strongly acid to moderately acid in the E, Bt and Btg horizons and strongly acid to mildly alkaline in the B't, BC and C horizons.
The A horizon has hue of 10YR, value of 4 or 5 and chroma of 3 or 4, or with value of 4 and chroma of 2. Texture is silt loam.
The E horizon, where present, has hue of 10YR, value of 5 or 6 and chroma of 1 or 2. Texure is silt loam or silt. Iron and accumulations are in shades of brown or red.
The Bt horizon has hue of 2.5YR or 5YR, value of 4 or 5, and chroma of 4 or 6. Iron accumulations and depletions are shades of brown, red or gray. Texture is silty clay loam, silty clay or clay.
The Btg horizon has hue of 10YR, value of 5 or 6 and chroma of 2. Iron accumulations and depletions are in shades of brown, red or gray. Texture is silty clay, silty clay loam or silt loam.
The B't horizon has hue of 10YR or 7.5YR, value of 4 or 5 and chroma of 3 to 6. Iron accumulations and depletions are in shades of brown, red or gray. Texture is silt loam or silty clay loam.
The BC horizon has hue of 10YR, value of 4 to 6 and chroma of 2 to 6. Iron accumulations and depletions are in shades of brown or gray. Texture is silt loam or silty clay loam.
The C horizon, where present, has hue of 10YR, value of 4 to 6, and chroma of 2 to 4. Iron accumulations and depletions are in shades of brown or gray. Texture is silt loam.
COMPETING SERIES: There no other series in this family.
GEOGRAPHIC SETTING: The Grubbs soils are on level to nearly level terrace treads immediately adjacent to the escarpment and on the nearly level to gently sloping escarpments of terraces in the Western Lowlands of the Lower Mississippi Valley; MLRA 131. Slopes are 0 to 8 percent. These soils exhibit the "Red Edge" effect, namely being better drained and containing less sodium than adjacent soils on the terrace tread. The average annual precipitation near the type location is about 50 inches; the average annual temperature is 61 degrees F.
PRINCIPAL ASSOCIATED SOILS: These include the Foley, Hillemann, Jackport, Overcup, and Tuckerman. Foley soils occur on lower terraces. They are poorly dained and contain a natric horizon. Hillemann soils occur on higher terraces. Hillemann soils are somewhat poorly drained and contain a natric horizon. Jackport and Overcup soils are on terrace treads. Jackport soils are poorly drained and in a smectitic mineralogy family. Overcup soils are poorly drained and in a smectitic mineralogy family. Tuckerman soils occur along drains below escarpments. They are poorly drained and in fine-loamy particle-size family.
DRAINAGE AND PERMEABILITY: Moderately well drained. Runoff is negligible to very high depending on slope. Permeability is very slow. A perched seasonal water table at about 24 to 30 inches during winter and early spring.
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USE AND VEGETATION: Most areas are cleared and cultivated. The main crops are rice, wheat and soybeans. Native vegetation was hardwood forest of sweetgum, pecan, and oaks.
DISTRIBUTION AND EXTENT: Lower Mississippi Valley; MLRA 131, mainly in Arkansas and Louisiana. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: AUBURN, ALABAMA
SERIES ESTABLISHED: Woodruff County, Arkansas; 1966.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epeipedon-surface to a depth of 5 inches. (Ap horizon)
Argillic horizon-5 to 64 inches (Bt1, Bt2, Bt3, Btg1, Btg2 and B't horizons)
Abrupt texture change between the Ap and Bt1 horizons.
The Grubbs series would have been classified as a claypan Planosol intergrading to Gray-Brown Podzolic great soil group in the 1938 soils classification system.
National Cooperative Soil Survey
U.S.A.