LOCATION GREENVINE TXEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Leptic Udic Haplusterts
TYPICAL PEDON: Greenvine clay loam--pasture. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 7 inches; very dark gray (10YR 3/1) clay loam, black (10YR 2/1) moist; moderate medium subangular blocky structure; very hard, firm; many fine and medium roots; moderately acid; clear smooth boundary.
A--7 to 18 inches; very dark gray (10YR 3/1) clay, black (10YR 2/1), moist; moderate coarse angular blocky structure parting to moderate very fine angular blocky; very hard, very firm; common fine roots; few fine and very fine pores; very few slickensides; moderately acid; gradual wavy boundary. (combined A subhorizons 4 to 20 inches thick)
Bss1--18 to 30 inches; dark gray (10YR 4/1) clay, black (10YR 2/1) moist; moderate coarse angular blocky structure parting to moderate fine angular blocky; very hard, very firm; common fine and medium roots, few fine and very fine pores; few coarse fragments 5 to 10mm across of silica enriched siltstone; common large slickensides; neutral; gradual wavy boundary.
Bss2--30 to 38 inches; light gray (10YR 6/1) clay, dark gray (10YR 4/1) moist; many coarse distinct grayish brown (10YR 5/2) moist and common medium distinct light yellowish brown (2.5Y 6/4) moist redox concentrations; weak coarse platy structure parting to strong fine angular blocky; very hard, very firm, sticky and plastic; few fine roots along cleavages; common slickensides; few fine iron-manganese masses; slight effervescence; slightly alkaline; clear wavy boundary. (combined Bss subhorizons 10 to 20 inches thick)
Cr1--38 to 55 inches; light brownish gray (2.5Y 6/2) tuffaceous siltstone, grayish brown (2.5Y 5/2) moist; common medium faint light olive brown (2.5Y 5/4) redox concentrations; few very dark gray (10YR 3/1) streaks along cracks; dominantly rock structure that is platy, but parts to weakly conchoidal; few fine roots along cleavages; common thin patchy calcium carbonate coatings along bedding planes; matrix is noncalcareous; slightly alkaline; clear irregular boundary.
Cr2--55 to 63 inches; light gray (2.5Y 7/2) tuffaceous siltstone, light brownish gray (2.5Y 6/2) moist; dominantly rock structure that is platy but parts to weakly conchoidal; few fine calcium carbonate masses between bedding planes; matrix is noncalcareous; neutral.
TYPE LOCATION: Washington County, Texas; 9 miles north of Brenham on Texas 36; 3 miles east on F. M. 390; 1.5 miles northwest on County Road 58; 1 mile northeast in pasture.
RANGE IN CHARACTERISTICS: Solum thickness and depth to a paralithic contact ranges from 20 to 40 inches. Depth to carbonates ranges from 6 inches to the depth of the paralithic contact. Texture of the A horizon is clay loam, clay or silty clay. Texture of the B horizon is clay or silty clay. Slickensides begin at a depth of about 15 inches. When dry, these soils have cracks more than 1/2 of and inch wide that extend from the surface to a depth of 20 inches or more for 90 to 150 cumulative days during most years. Cycles of microdepression and microknolls are repeated each 10 to 15 feet. In undisturbed areas ther is gilgai microrelief with microknolls 4 to 12 inches higher than microdepressions. The boundary between the A and B horizon is wavy with amplitude of 10 to 25 inches.
The A horizon averages more than 12 inches thick in 50 percent or more of the pedon. The color has hue of 10YR or N, value of 2 to 5, and chroma of 1 or less. Slickensides and pressure faces range from none to very few. Reaction ranges from strongly acid to neutral in microdepressions and neutral to moderately alkaline in microknolls. The boundary is clear wavy or gradual wavy.
The Bss horizon has hue of 10YR, 2.5Y, and 5Y, value of 4 to 6, and chroma of 1 or 2. Low chroma colors are not indicative of present day wetness. Slickensides range from few to common. The reaction is neutral or slightly alkline alkaline. It is very slightly effervescent in some pedons.
Some pedons have a Bkss horizon. It has colors with hue and value like the Bss horizon. However, the chroma ranges to 4. Calcium carbonate threads, masses, or concentrations range from common to many.
The Cr horizon is weakly or strongly cemented clayey tuff, clayey shale or fine grained tuffaceous sandstone.
COMPETING SERIES: These are the Crawford, Dalco, and San Saba soils. Dalco soils are very slightly to strongly effervescent with a paralithic contact of chalk. Crawford and San Saba soils have lithic contact of limestone at a depth of 24 to 40 inches. Crawford soils also have hue redder than 7.5YR in the Bss horizon.
GEOGRAPHIC SETTING: Greenvine soils are on gently sloping to moderately sloping convex uplands. Slopes range from 1 to 8 percent, but are mainly 1 to 3 percent. The soils formed in residuum weathered from tuffaceous shales, siltstones, or fine grained sandstones of the Catahoula and similar geological formations. The mean annual temperature ranges from 65 to 70 degrees F. and mean annual precipitation ranges from 34 to 40 inches. Frost free days range from 260 to 290 days and elevation ranges from 200 to 550 feet. Thornthwaite P-E indices range from 48 to 64.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Arol, Burlewash, Falba, Rehburg, and Shalba series. Arol, Burlewash, Falba, and Rehburg soils have argillic horizons, and do not have large slickensides. Arol and Falba soils are on lower wetter positions. Burlewash and Rehburg soils are on similar upland positions. Shalba soils are on slightly higher convex positions. Shalba soils do not have vertic properties.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is very slow. However, water enters the soil rapidly when it is dry and cracked. Runoff is medium on 1 to 3 percent slopes, high on 3 to 5 percent slopes, and very high on slopes greater than 5 percent.
USE AND VEGETATION: Used mainly for improved bermudagrass pasture. A few areas are used for cropland. Native vegetation consists of mid and tall prairie grasses.
DISTRIBUTION AND EXTENT: Southern Claypan Area of Texas (MLRA 87A). The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Washington County, Texas, 1978.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 30 inches. (Ap, A and Bss horizons)
Cambic horizon - 18 to 38 inches. (Bss horizon)
Low chroma colors are not indicative of present day wetness.
Large slickensides - 18 to 38 inches.
Cracks that remain open between 90 and 150 cumulative days during most years.
Paralithic contact - at 38 inches.
ADDITIONAL DATA: Soil characterization data from type location - Lab. nos. 1953-1958; pedon No.583TX-447-01 by Texas A&M University.