LOCATION NEFF OK+AREstablished Series
The Neff series consists of very deep, moderately well drained, moderately slowly permeable soils that formed in loamy alluvium. These nearly level or very gently sloping soils are on broad flood plains in the valleys of the Ouachita Mountains, MLRA 119, and Arkansas Valley and Ridges, MLRA 118. They are saturated in winter and spring. Slope is dominantly less than 1 percent but ranges up to 3 percent. Mean annual temperature is 63 degrees F., and mean annual precipitation is 46 inches.
TAXONOMIC CLASS: Fine-silty, siliceous, active, thermic Aquultic Hapludalfs
TYPICAL PEDON: Neff silt loam--on a very gently undulating 0.5 percent slope, in pasture. (Colors are for moist soil unless otherwise stated.)
A--0 to 14 inches; brown (10YR 4/3) silt loam; brown (10YR 5/3) dry; weak fine granular structure; friable; neutral; gradual smooth boundary. (7 to 16 inches thick)
BA--14 to 23 inches; dark yellowish brown (10YR 4/4) silt loam; weak medium subangular blocky structure; friable; few patchy clay films on faces of peds; few fine distinct light brownish gray (10YR 6/2) and common medium faint brown (10YR 5/3) iron depletions; few fine yellowish brown and black concretions; strongly acid; gradual smooth boundary. (0 to 13 inches thick)
Bt--23 to 57 inches; dark yellowish brown (10YR 4/4) silty clay loam; weak medium subangular blocky structure; friable; patchy clay films on faces of peds; many medium distinct light brownish gray (10YR 6/2) and pale brown (10YR 6/3) iron dpletions; common fine yellowish brown and black concretions; strongly acid; gradual smooth boundary. (28 to 49 inches thick)
BC--57 to 82 inches; dark yellowish brown (10YR 4/4) silty clay loam; weak medium subangular blocky structure; friable; patchy clay films on faces of peds; common fine and medium distinct gray (10YR 6/1) and common fine and medium faint light yellowish brown (10YR 6/4) iron depletions; common fine yellowish brown and black concretions; very strongly acid.
TYPE LOCATION: LeFlore County, Oklahoma; about 4 miles southwest of Poteau; 1,450 feet west and 850 feet north of the southeast corner of Sec. 15, T. 6 N., R. 25 E.
RANGE IN CHARACTERISTICS: Solum thickness is more than 60 inches.
The A horizon has hue of 10YR, value of 4 or 5, and chroma of 2 to 4. It is loam or silt loam and the clay content ranges from 15 to 25 percent. Reaction ranges from medium acid to very strongly acid, except where it has been limed and then it ranges to neutral.
The BA horizon has hue of 10YR, value of 4 to 6, and chroma of 2 to 4. Iron depletions and accumulations are in shades of gray or brown. Texture is loam or silt loam and the clay content ranges from 18 to 26 percent. Reaction ranges from medium acid to very strongly acid.
The Bt horizon has hue of 10YR, value of 4 to 8, and chroma of 2 to 4. Iron accumulations and depletions are in shades of gray and brown. Texture is silt loam or silty clay loam and the clay content ranges from 25 to 35 percent. Reaction ranges from slightly acid to very strongly acid.
The BC horizon has hue of 10YR, value of 4 or 5, and chroma of 3 or 4. Iron accumulations and depletions are in shades of gray, brown, or yellow. Texture is silt loam or silty clay loam and the clay content ranges from 18 to 35 percent. Reaction ranges from slightly acid to very strongly acid. Sandstone fragments less than 3 inches in diameter make up 0 to 15 percent by volume.
COMPETING SERIES: There are no other series in this family. Soils in closely related families include the Arney and Treharne series with mixed mineralogy and mesic temperature regime, and the Nikful series with fine textural family and smectitic mineralogy.
GEOGRAPHIC SETTING: Neff soils are on broad nearly level or very gently sloping flood plains in the valleys of the Ouachita Mountains and the Arkansas Valley and Ridges. Slopes are 0 to 3 percent. These soils formed in loamy alluvium. The climate is humid. Mean annual precipitation ranges from 40 to 56 inches. Mean annual temperature ranges from 61 degrees to 64 degrees F. Thornthwaite annual P-E indices range from 64 to 76.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cupco, Dela, Kenn, Pocola, Rexor, and Speer series. Cupco and Pocola soils occur on slighty concave areas. Dela soils occur on similar landscapes closer to the stream channel, are coarse-loamy, and relatively younger. Kenn soils commonly occur upstream closer to the source of sediments, and are fine-loamy. Pocola soils have more than 35 percent clay content in the control section and aquic moisture regime. Rexor soils occur on slightly higher convex areas. Speer soils have a fine-loamy control section, are well drained, and occur on similar landscape positions.
DRAINAGE AND PERMEABILITY: Neff soils are moderately well drained. Runoff is slow, and permeability is moderately slow. A water table is at a depth of 0.5 to 2.5 feet in winter and spring. These soils are subject to occasional or frequent flooding for brief or very brief periods from November to June.
USE AND VEGETATION: Used mainly for growing tame pasture for beef cattle. Minor areas are used for woodland or used for growing soybeans. The main trees are green ash, sweetgum, water oak, and willow oak.
DISTRIBUTION AND EXTENT: Arkansas Valley and Ridges, MLRA 118, and the Ouachita Mountains, MLRA 119, of eastern Oklahoma and western Arkansas. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Latimer County, Oklahoma; 1980.
REMARKS: These soils were formerly included in the Rexor series. ADDITIONAL DATA: Oklahoma State University, sample 74-OK-40-6.