LOCATION NECESSITY LAEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, active, thermic Aquic Fraglossudalfs
TYPICAL PEDON: Necessity silt loam, on less than 1.0 percent slope in cotton field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 6 inches; brown (10YR 4/3) silt loam; few fine faint brown mottles; weak medium granular structure; friable; common fine roots; medium acid; abrupt wavy boundary. (4 to 10 inches thick)
Bt--6 to 17 inches; yellowish brown (10YR 5/4) silty clay loam; common medium faint grayish brown (10YR 5/2) and common fine distinct strong brown mottles; moderate medium subangular blocky structure; friable; few fine roots; common fine pores; few faint clay films on faces of peds; few medium reddish brown concretions; strongly acid; clear wavy boundary. (5 to 15 inches thick)
B/E--17 to 25 inches; pale brown (10YR 6/3) silt loam; common medium distinct brown (7.5YR 4/4) mottles; the A portion is grayish brown (10YR 5/2) silt loam and makes up to 30 percent of the horizon; weak medium subangular blocky structure; friable; pockets of slightly brittle material in B portion; few fine roots; few fine pores; common faint clay films on faces of peds; common fine and medium reddish brown concretions; strongly acid; clear irregular boundary. (5 to 20 inches thick)
E--25 to 28 inches; light brownish gray (10YR 6/2) silt loam; few fine faint brown mottles; weak medium subangular blocky structure; friable; slightly brittle; common fine and medium pores; common fine and medium brown concretions; strongly acid; clear irregular boundary. (0 to 6 inches thick)
Btx1--28 to 38 inches; brown (10YR 4/3) loam; common medium faint brown (7.5YR 4/4) mottles; weak very coarse prismatic structure parting to moderate medium subangular blocky; slightly hard, brittle; common fine and medium pores; few faint clay films on faces of peds; few medium brown concretions; few dark stains on faces of peds; tongues and interfingers of light brownish gray silt loam between prisms make up about 10 percent of horizon; strongly acid; clear wavy boundary. (10 to 20 inches thick)
Btx2--38 to 52 inches; strong brown (7.5YR 4/4) loam; common medium distinct yellowish brown (10YR 5/4) mottles; common brown (7.5YR 5/2) ped coatings; weak very coarse prismatic structure parting to moderate medium subangular blocky; firm, brittle; common medium pores; few faint clay films on faces of peds; few dark stains on surfaces of peds; common thin gray silt coatings between prisms; strongly acid; clear smooth boundary. (10 to 20 inches thick)
BC--52 to 67 inches; brown (7.5YR 4/4) clay loam; weak medium subangular blocky structure; friable; common faint films on vertical faces of peds; few distinct gray silt coatings on faces on peds; strongly acid; clear smooth boundary. (5 to 20 inches thick)
TYPE LOCATION: Franklin Parish, Louisiana; 3.0 miles southwest of Fort Necessity; 15 feet north of State Highway 872 right-of-way; northwest 1/4 southwest 1/4, sec. 22, T. 12 N., R. 6 E.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 50 to 80 inches. Depth to the fragipan ranges from 20 to 37 inches. Sand content ranges from 10 to 35 percent with less than 15 percent coarser than very fine sand in the upper 20 inches of the argillic horizon. Reaction, except for those surface layers that have been limed, ranges from medium acid to very strongly acid above the fragipan, from slightly acid to very strongly acid in the Btx and BC horizons and from mildly alkaline to very strongly acid in the C horizon. The effective cation exchange capacity typically ranges from 15 to 50 percent, saturated with exchangeable aluminum within 30 inches of the surface.
The A horizon has hue of 10YR, value of 4 to 6, and chroma of 1 or 3. Texture is very fine sandy loam or silt loam.
The Bt horizon has hue of 10YR, value of 4 to 6, and chroma of 3 to 6. Texture is loam, silt loam, clay loam, or silty clay loam. The clay content ranges from 18 to 32 percent. Mottles are in shades of gray, yellow, or brown. Fine and medium black, brown, or red concretions range from few to common.
The E horizon has hue of 10YR, value of 5 to 7, and chroma of 2 or 3. Mottles are in shades of brown or gray. Texture is silt loam. Fine or medium black, brown, or red concretions range from few to many.
The Btx horizon has hue of 7.5YR or 10YR, value of 4 or 5, and chroma of 2 to 6. texture is loam, silt loam, or clay loam. Mottles are in shades of gray, yellow, or brown. Concretions range from none to common. The brittle matrix ranges from 60 to 80 percent of the horizontal cross section.
The BC horizon has hue of 7.5YR or 10YR, value of 4 to 6, and chroma of 3 to 6. Texture is loam, silt loam, or clay loam. Concretions range from none to common. Mottles in shades of gray or brown range from none to common.
The C horizon has hue of 7.5YR or 10YR, value of 4 to 6, and chroma of 3 to 6. Texture is clay loam, loam, very fine sandy loam, or loamy fine sand.
COMPETING SERIES: These are the Bude and Calloway series in the same family and the Coteau series. Bude and Calloway soils do not have an argillic horizon above the fragipan. Coteau soils do not have fragipan horizons. Also, Bude soils have less than 10 percent sand in the upper parts of the solum and Calloway soils have less than 10 percent sand throughout the solum.
GEOGRAPHIC SETTING: Necessity soils are on nearly level areas and on low ridges and knolls on Pleistocene age stream terraces of former channels of the Arkansas River. Slopes are mainly less than 1 percent, but range up to 5 percent along narrow drainageways. The climate is warm and humid. The average annual precipitation ranges from 45 to 55 inches. The mean annual temperature ranges from 60 to 70 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Deerford, Dexter, Egypt, Foley, Forestdale, Gigger, Gilbert and Liddieville series. Deerford soils are on slightly lower lying areas and have natric horizons. Dexter and Gilbert soils are on higher ridges and have redder hues. Egypt soils are on slightly lower lying areas and have lower sand content. Foley soils are in depressions and have natric horizons. Forestdale soils are in depressions and have fine textured argillic horizons. Gilbert soils are in depressions and have lower chroma. Liddieville soils are on high lying convex ridges and have a fine-loamy argillic horizon.
DRAINAGE AND PERMEABILITY: Necessity soils are somewhat poorly drained. Runoff is slow. Permeability is slow. A water table is perched above the fragipan from December to April.
USE AND VEGETATION: Used mainly for growing cotton and soybeans and as pastureland.
DISTRIBUTION AND EXTENT: Louisiana, and possibly Arkansas and Oklahoma. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Franklin Parish, Louisiana; 1979.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon..................0 to 6 inches (Ap)
Albic horizon ..................25 to 28 inches (E)
Argillic horizon................6 to 17 inches (Bt)
Fragipan................28 to 62 inches (Btx1,Btx2)
Glossic features.............28 to 38 inches (Btx1)
Aquic moisture regime