LOCATION VARRO TXEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, calcareous, thermic Typic Udifluvents
TYPICAL PEDON: Varro clay loam--forested.
(Colors are for moist soil unless otherwise stated.)
A--0 to 7 inches; dark grayish brown (10YR 4/2) clay loam, few fine distinct mottles of yellowish brown; weak subangular blocky and granular structure; hard, friable; few fine roots and decaying leaves; calcareous; moderately alkaline; abrupt smooth boundary. (4 to 12 inches thick)
C--7 to 60 inches; grayish brown (2.5Y 5/2) clay loam; thin strata of light brownish gray (2.5Y 6/2) loam and slightly more clayey strata of dark grayish brown (2.5Y 4/2) up to 1/4-inch thick; few thin strata very dark gray (10YR 3/1) silty clay below 40 inches; massive; hard, friable; few fine roots; calcareous; moderately alkaline.
TYPE LOCATION: Red River County, Texas; south of Clarksville on State Highway 37 to Farm Road 196; west of Farm Road 196 for 4 miles to private road; south on private levee road 2.5 miles; site is 1,300 feet south of levee road in woods on Lamar-Red River County Line.
RANGE IN CHARACTERISTICS: Depth of alluvium ranges from about 10 to 40 feet. The control section is stratified loam, silt loam, silty clay loam, and clay loam. The clay content averages between 20 and 30 percent. Bedding planes are evident throughout the soil below the A horizon and range from less than an inch to about two inches thick. It is mildly alkaline or moderately alkaline and calcareous throughout.
The A horizon has colors with hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 2 to 4. Some pedons have moist values of 3 but these horizons are less than 7 inches thick. The texture is mainly loam, clay loam or silty clay loam.
The C horizons have colors with hue of 10YR or 2.5Y, value of 4 to 7, and chroma of 2 to 4. Thin strata of black or very dark gray are in some pedons. The 2 chroma colors are inherited from the high lime parent material.
COMPETING SERIES: There are no other series in this family. Similar competing soils include the Bunyan, Clemville, Colorado, Energy, Norwood, and Severn series. Bunyan soils are noncalcareous and members of the Ustic moisture regime. Clemville and Norwood soils have fine-silty control sections. Colorado and Energy soils are dry for longer periods and members of the Ustic moisture regime. Severn soils have coarse-silty control sections.
GEOGRAPHIC SETTING: Varro soils are on nearly level natural levees in flood plains of streams. Slopes are mainly less than 1 percent, but range up to 2 percent. These soils formed in stratified, calcareous alluvium. The climate is warm and humid to moist sub- humid. The average annual precipitation ranges from about 38 to 55 inches. The average annual temperature ranges from about 64 to 70 degrees F. The Thronthwaite P-E index ranges from 50 to 80.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Kaufman, Kemp, and Trinity soils. Kaufman and Trinity soils have fine textured control sections. Kemp soils are members of an aquic subgroup. All of these soils are in similar flood plain positions.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; medium internal drainage; moderate permeability. Where unprotected, flooding occurs at intervals of about one to three times each year but water usually remains on the surface for less than 48 hours during any one flooding.
USE AND VEGETATION: Used for pasture and cropland, with some areas in woodland pasture. The original vegetation includes elm, cottonwood, hackberry, pecan trees, greenbrier, buck brush, and coarse bunch grasses.
DISTRIBUTION AND EXTENT: Mainly in the Blackland Prairie, Texas Claypan, and Coastal Plain of eastern Texas. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Red River County, Texas; 1972.