LOCATION MAMOU LAEstablished Series
TAXONOMIC CLASS: Fine-silty, siliceous, active, thermic Aeric Albaqualfs
TYPICAL PEDON: Mamou silt loam--in pasture on a convex 2 percent side slope. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 6 inches; grayish brown (10YR 5/2) silt loam; weak fine granular structure; friable; common fine roots; few black stains; common fine distinct yellowish brown (10YR 5/4) iron accumulations; many fine black masses; slightly acid; clear smooth boundary. (3 to 8 inches thick)
E--6 to 11 inches; yellowish brown (10YR 5/4) silt loam; weak medium subangular blocky structure; friable; few fine roots; common fine pores; common fine distinct grayish brown (10YR 5/2) iron depletions; few medium red masses; slightly acid; abrupt wavy boundary. (3 to 10 inches thick)
Btg1--11 to 19 inches; mixed dark gray (10YR 4/1), very dark gray (10YR 3/1), and dark red (2.5YR 3/6) silty clay loam; surfaces of peds are very dark gray (10YR 3/1); weak coarse prismatic structure parting to strong medium subangular blocky; firm; few fine roots along surface of peds; few fine pores; many prominent clay films on surfaces of peds; few fine black and brown masses; slightly acid; clear wavy boundary. (6 to 18 inches thick)
Btg2--19 to 26 inches; yellowish brown (10YR 5/4) silty clay loam with dark grayish brown (10YR 4/2) coatings on surface of peds; moderate medium subangular blocky structure; firm; few fine roots; few fine pores; many prominent clay films on surface of peds; many medium black stains on surfaces of peds; few fine red and black masses; slightly acid; diffuse wavy boundary. (4 to 14 inches thick)
C--26 to 64 inches; mixed light yellowish brown (10YR 6/4) and yellowish brown (10YR 5/4) loam; massive; common medium distinct strong brown (7.5YR 5/8) iron concentrations; firm; few medium brown concretions with red interiors; neutral.
TYPE LOCATION: Evangeline Parish, Louisiana; 5 miles south of Mamou; 1.2 miles west of Fenris Junction, 72 yards south of highway; NW1/4SE1/4 sec. 2, T. 6 S., R 1 W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 20 to 50 inches. Weighted average clay content of the A and E horizons ranges from 5 to 15 percent and 25 to 35 percent in the Bt horizon. Thickness of the A and E horizons and depth to the abrupt textural change ranges from 6 to 18 inches.
The A or Ap horizon has hue of 10YR, value of 4 or 5, and chroma of 1 or 2. Texture is silt loam, loam, or very fine sandy loam. Yellowish or grayish brown iron concentrations range from none to common. Reaction ranges from very strongly acid to slightly acid.
The E horizon has hue of 10YR, value of 4 to 6, and chroma of 3 to 6. Texture is silt loam, loam, or very fine sandy loam. Yellowish or grayish brown iron concentrations range from none to common. Iron depletions with chroma of 2 or less range from few to many. Reaction ranges from very strongly acid to slightly acid.
The Bt horizon has ped coatings with hue of 10YR or 2.5Y, value of 3 to 5, and chroma of 1 or 2. Ped interiors have hue of 7.5YR or 10YR, value of 3 to 6, and chroma 4 to 8 with grayish and reddish iron depletions and concentrations, or have mixed colors in shades of gray, brown, and red. Reaction ranges from very strongly acid to slightly acid
The C horizon has mixed colors in shades of brown, red, or gray. Texture is loam, silt loam, or silty clay loam. Some pedons have thin clayey strata. Reaction ranges from slightly acid to slightly alkaline.
COMPETING SERIES: There are no other series in this family. Series in similar families are the Acadiana, Crowley, Dundee, Homa, Patoutville, Springfield, Tenot, and Zachary series. Acadiana, Crowley, and Springfield soils have a fine particle-size control section. In addition, Crowley soils do not have chroma of 3 or more in the E or upper Bt horizons. Dundee, Houma, Springfield, and Tenot soils are in the thermic temperature regime. In addition, Dundee soils do not have an E horizon. Homa soils have a very-fine particle-size control section. Patoutville soils are in a superactive family and have less than 10 percent sand in the Bt horizons. Tenot soils have less than 10 percent sand and sola more than 50 inches thick. Zachary soils are poorly drained and have grayer soil colors in the Bt horizon.
GEOGRAPHIC SETTING: Mamou soils are on the inside slopes of the natural levee of long, narrow, constructional stream channels of the late Pleistocene age Prairie Terrace Formation. Slope ranges from 1 to 3 percent. The soil formed in silty and sandy deltaic alluvium. Mean annual temperature ranges from 68 to 70 degrees F. Mean annual precipation ranges from 55 to 65 inches. Frost free days range from 280 to 350. Elevation ranges from 50 to 150 feet. Thornthwaite P-E index ranges from 60 to 80.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Acadiana, Crowley, and Patoutville series and the Mowata and Kinder series. Acadiana soils are on the same to slightly lower landscape positions. The poorly drained Mowata soils are on lower concave landscape positions. The somewhat poorly drained Crowley and poorly Kinder soils are on nearly level areas lower in the landscape.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Permeability is slow. Runoff is medium. Water is perched at depths of 0.5 to 1.0 foot for short periods mostly during the winter and spring.
USE AND VEGETATION: Used mainly for growing cotton, corn, sweet potatoes, rice, soybeans, and pasture. Native vegetation is tall prairie grasses.
DISTRIBUTION AND EXTENT: Gulf Coast Prairie of Southwest Louisiana and possibly Texas (MLRA 150A, LRR T). The series is moderately extensive.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Evangeline Parish, Louisiana; 1970.
REMARKS: These soils were formerly included in the Crowley series.
Diagnostic horizons and features recognized in this pedon are;
Ochric epipedon--0 to 11 inches (Ap & E horizons).
Abrupt textural change--the contact at 11 inches has a clay increase that doubles within 3 inches.
Argillic horizon--11 to 26 inches (Btg horizons).
Aeric feature--chroma of 3 or more in more than 40 percent of the argillic horizon to a depth of 30 inches.
ADDITIONAL DATA: none
TAXONOMIC VERSION: Keys to Soil Taxonomy, Ninth Edition, 2003.